Disc brake - Revision history

Headbomb: ce

2024-08-14T20:17:11Z

← Previous revision		Revision as of 20:17, 14 August 2024
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	===Cracking===		===Cracking===
	Cracking is limited mostly to drilled discs, which may develop small cracks around the edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe-duty environments. Manufacturers that use drilled discs as [[Original Equipment Manufacturer\|OEM]] typically do so for two reasons: appearance, if they determine that the average owner of the vehicle model will prefer the look while not overly stressing the hardware; or as a function of reducing the [[unsprung weight]] of the brake assembly, with the engineering assumption that enough brake disc mass remains to absorb racing temperatures and stresses. A brake disc is a [[heat sink]], but the loss of heat sink mass may be balanced by increased surface area to radiate away heat. Small hairline cracks may appear in any cross-drilled metal disc as a normal wear mechanism, but in severe cases, the disc will fail catastrophically. No repair is possible for the cracks, and if the cracking becomes severe, the disc must be replaced. These cracks occur due to the phenomenon of low cycle fatigue as a result of repeated hard braking.<ref name="2013_rashid_discbrakes">{{cite journal\|last1=Rashid\|first1=Asim \|last2=Strömberg \|date=17 October 2015 \|title=Sequential simulation of thermal stresses in disc brakes for repeated braking \|url= http://hj.diva-portal.org/smash/get/diva2:618167/FULLTEXT01 \|journal=Proceedings of the Institution of Mechanical Engineers, Part J, Journal of Engineering Tribology \|volume=227 \|issue=8 \|pages=919{{ndash}}929 \|doi=10.1177/1350650113481701 \|s2cid=3468646 \|access-date=18 February 2024}}</ref>		Cracking is limited mostly to drilled discs, which may develop small cracks around the edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe-duty environments. Manufacturers that use drilled discs as [[Original Equipment Manufacturer\|OEM]] typically do so for two reasons: appearance, if they determine that the average owner of the vehicle model will prefer the look while not overly stressing the hardware; or as a function of reducing the [[unsprung weight]] of the brake assembly, with the engineering assumption that enough brake disc mass remains to absorb racing temperatures and stresses. A brake disc is a [[heat sink]], but the loss of heat sink mass may be balanced by increased surface area to radiate away heat. Small hairline cracks may appear in any cross-drilled metal disc as a normal wear mechanism, but in severe cases, the disc will fail catastrophically. No repair is possible for the cracks, and if the cracking becomes severe, the disc must be replaced. These cracks occur due to the phenomenon of low cycle fatigue as a result of repeated hard braking.<ref name="2013_rashid_discbrakes">{{cite journal\|last1=Rashid\|first1=Asim \|last2=Strömberg \|date=17 October 2015 \|title=Sequential simulation of thermal stresses in disc brakes for repeated braking \|url= http://hj.diva-portal.org/smash/get/diva2:618167/FULLTEXT01 \|journal=Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology \|volume=227 \|issue=8 \|pages=919{{ndash}}929 \|doi=10.1177/1350650113481701 \|s2cid=3468646 \|access-date=18 February 2024}}</ref>

	===Rusting===		===Rusting===

Quack5quack: /* Design */Grammar fix (need adverb not adjective)

2024-08-14T17:10:27Z

Design: Grammar fix (need adverb not adjective)

← Previous revision		Revision as of 17:10, 14 August 2024
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	The development of disc-type brakes began in England in the 1890s. In 1902, the [[Lanchester Motor Company]] designed brakes that looked and operated similarly to a modern disc-brake system even though the disc was thin and a cable activated the brake pad.<ref name="hemmings1">{{cite web\|last=Lentinello \|first =Richard \|title=The first car with disc brakes really was . . . \|url= https://www.hemmings.com/magazine/hsx/2011/04/The-first-car-with-disc-brakes-really-was------/3698201.html \|work=Hemmings Sports & Exotic Car \|date=April 2011 \|access-date=26 November 2017}}</ref> Other designs were not practical or widely available in cars for another 60 years. Successful application began in airplanes before World War II. The [[Tiger I\|German Tiger]] tank was fitted with discs in 1942. After the war, technological progress began in 1949, with caliper-type four-wheel disc brakes on the [[Crosley]] line and a Chrysler non-caliper type. In the 1950s, there was a demonstration of superiority at the [[1953 24 Hours of Le Mans]] race, which required braking from high speeds several times per lap.<ref name="GiganticLeap"/> The [[Jaguar Cars\|Jaguar]] racing team won, using disc brake-equipped cars, with much of the credit being given to the brakes' superior performance over rivals equipped with [[drum brake]]s.<ref name="GiganticLeap"/> Mass production began with the 1949–1950 inclusion in all Crosley production, with sustained mass production starting in 1955 [[Citroën DS]].<ref name="hemmings1"/>		The development of disc-type brakes began in England in the 1890s. In 1902, the [[Lanchester Motor Company]] designed brakes that looked and operated similarly to a modern disc-brake system even though the disc was thin and a cable activated the brake pad.<ref name="hemmings1">{{cite web\|last=Lentinello \|first =Richard \|title=The first car with disc brakes really was . . . \|url= https://www.hemmings.com/magazine/hsx/2011/04/The-first-car-with-disc-brakes-really-was------/3698201.html \|work=Hemmings Sports & Exotic Car \|date=April 2011 \|access-date=26 November 2017}}</ref> Other designs were not practical or widely available in cars for another 60 years. Successful application began in airplanes before World War II. The [[Tiger I\|German Tiger]] tank was fitted with discs in 1942. After the war, technological progress began in 1949, with caliper-type four-wheel disc brakes on the [[Crosley]] line and a Chrysler non-caliper type. In the 1950s, there was a demonstration of superiority at the [[1953 24 Hours of Le Mans]] race, which required braking from high speeds several times per lap.<ref name="GiganticLeap"/> The [[Jaguar Cars\|Jaguar]] racing team won, using disc brake-equipped cars, with much of the credit being given to the brakes' superior performance over rivals equipped with [[drum brake]]s.<ref name="GiganticLeap"/> Mass production began with the 1949–1950 inclusion in all Crosley production, with sustained mass production starting in 1955 [[Citroën DS]].<ref name="hemmings1"/>

	Disc brakes offer better stopping performance than drum brakes because the disc is more readily cooled. Consequently, discs are less prone to the [[brake fade]] caused when brake components overheat. Disc brakes also recover ~~quicker~~ from immersion (wet brakes are less effective than dry ones).<ref name="GiganticLeap"/>		Disc brakes offer better stopping performance than drum brakes because the disc is more readily cooled. Consequently, discs are less prone to the [[brake fade]] caused when brake components overheat. Disc brakes also recover more quickly from immersion (wet brakes are less effective than dry ones).<ref name="GiganticLeap"/>

	Most drum brake designs have at least one leading shoe, which gives a [[Servomechanism\|servo-effect]]. By contrast, a disc brake has no self-servo effect, and its braking force is always proportional to the pressure placed on the brake pad by the braking system via any brake servo, brake pedal, or lever. This tends to give the driver a better "feel" and helps to avoid impending lockup. Drums are also prone to "bell mouthing" and trap worn lining material within the assembly, causing various braking problems.{{Cn\|date=August 2024}}		Most drum brake designs have at least one leading shoe, which gives a [[Servomechanism\|servo-effect]]. By contrast, a disc brake has no self-servo effect, and its braking force is always proportional to the pressure placed on the brake pad by the braking system via any brake servo, brake pedal, or lever. This tends to give the driver a better "feel" and helps to avoid impending lockup. Drums are also prone to "bell mouthing" and trap worn lining material within the assembly, causing various braking problems.{{Cn\|date=August 2024}}

GraemeLeggett: /* Judder or shimmy */ citation issues

2024-08-13T07:59:48Z

Judder or shimmy: citation issues

← Previous revision		Revision as of 07:59, 13 August 2024
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	[[File:Ferrari F430 Challenge Brake.JPG\|thumb\|[[Reinforced carbon–carbon\|Reinforced carbon]] brake disc on a [[Ferrari F430]] [[Ferrari Challenge\|Challenge]] race car]][[File:Oreca 07 No.99 JDC-Miller Motorsports 2018 12 Hours of Sebring.jpg\|thumb\|Front disk brakes glowing during a race]]		[[File:Ferrari F430 Challenge Brake.JPG\|thumb\|[[Reinforced carbon–carbon\|Reinforced carbon]] brake disc on a [[Ferrari F430]] [[Ferrari Challenge\|Challenge]] race car]][[File:Oreca 07 No.99 JDC-Miller Motorsports 2018 12 Hours of Sebring.jpg\|thumb\|Front disk brakes glowing during a race]]

	In racing and high-performance road cars, other disc materials have been employed. [[Reinforced carbon–carbon\|Reinforced carbon]] discs and pads inspired by aircraft braking systems such as those used on [[Concorde]] were introduced in [[Formula One]] by [[Brabham]] in conjunction with [[Dunlop Rubber\|Dunlop]] in 1976.<ref>{{cite book \|last=Henry \|first=Alan \|year=1985 \|title=Brabham, the Grand Prix Cars \|page=163 \|publisher=Osprey \|isbn=978-0-905138-36-7 }}</ref> [[Reinforced carbon–carbon\|Carbon–carbon]] braking is now used in most top-level motorsport worldwide, reducing [[unsprung weight]], giving better frictional performance and improved structural properties at high temperatures, compared to cast iron. Carbon brakes have occasionally been applied to road cars, by the French Venturi sports car manufacturer in the mid-1990s for example, but need to reach a very high [[operating temperature]] before becoming truly effective and so are not well suited to road use. The extreme heat generated in these systems is visible during night racing, especially on shorter tracks. It is not uncommon to see the brake discs glowing red during use.		In racing and high-performance road cars, other disc materials have been employed. [[Reinforced carbon–carbon\|Reinforced carbon]] discs and pads inspired by aircraft braking systems such as those used on [[Concorde]] were introduced in [[Formula One]] by [[Brabham]] in conjunction with [[Dunlop Rubber\|Dunlop]] in 1976.<ref>{{cite book \|last=Henry \|first=Alan \|year=1985 \|title=Brabham, the Grand Prix Cars \|page=163 \|publisher=Osprey \|isbn=978-0-905138-36-7 }}</ref> [[Reinforced carbon–carbon\|Carbon–carbon]] braking is now used in most top-level motorsport worldwide, reducing [[unsprung weight]], giving better frictional performance and improved structural properties at high temperatures, compared to cast iron. Carbon brakes have occasionally been applied to road cars, by the French Venturi sports car manufacturer in the mid-1990s for example, but need to reach a very high [[operating temperature]] before becoming truly effective and so are not well suited to road use. The extreme heat generated in these systems is visible during night racing, especially on shorter tracks. It is not uncommon to see the brake discs glowing red during use.{{Cn\|date=August 2024}}

	===Ceramic composites===		===Ceramic composites===
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	Often uneven pad transfer is confused for disc warping.<ref>{{cite web \|url=http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths \|first=Carroll \|last=Smith \|title=Warped- Brake Disc and Other Myths \|website=Stoptech.com \|access-date=18 January 2014 \|archive-date=11 January 2014 \|archive-url=https://web.archive.org/web/20140111042612/http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths \|url-status=dead }}</ref> The majority of brake discs diagnosed as "warped" are the result of uneven transfer of pad material. Uneven pad transfer can lead to thickness variation of the disc. When the thicker section of the disc passes between the pads, the pads will move apart and the brake pedal will raise slightly; this is pedal pulsation. The thickness variation can be felt by the driver when it is approximately {{convert\|0.17\|mm\|in\|4\|abbr=on}} or greater (on automobile discs).		Often uneven pad transfer is confused for disc warping.<ref>{{cite web \|url=http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths \|first=Carroll \|last=Smith \|title=Warped- Brake Disc and Other Myths \|website=Stoptech.com \|access-date=18 January 2014 \|archive-date=11 January 2014 \|archive-url=https://web.archive.org/web/20140111042612/http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths \|url-status=dead }}</ref> The majority of brake discs diagnosed as "warped" are the result of uneven transfer of pad material. Uneven pad transfer can lead to thickness variation of the disc. When the thicker section of the disc passes between the pads, the pads will move apart and the brake pedal will raise slightly; this is pedal pulsation. The thickness variation can be felt by the driver when it is approximately {{convert\|0.17\|mm\|in\|4\|abbr=on}} or greater (on automobile discs).

	Thickness variation has many causes, but three primary mechanisms contribute to the propagation of disc thickness variations. The first is the improper selection of brake pads. Pads that are effective at low temperatures, such as when braking for the first time in cold weather, often are made of materials that decompose unevenly at higher temperatures. This uneven decomposition results in the uneven deposition of material onto the brake disc. Another cause of uneven material transfer is the improper break-in of a pad/disc combination. For proper break-in, the disc surface should be refreshed (either by machining the contact surface or by replacing the disc) every time the pads are changed. Once this is done, the brakes are heavily applied multiple times in succession. This creates a smooth, even interface between the pad and the disc. When this is not done properly the brake pads will see an uneven distribution of stress and heat, resulting in an uneven, seemingly random, deposition of pad material. The third primary mechanism of uneven pad material transfer is "pad imprinting." This occurs when the brake pads are heated to the point that the material begins to break down and transfer to the disc. In a properly broken-in brake system (with properly selected pads), this transfer is natural and is a major contributor to the braking force generated by the brake pads. However, if the vehicle comes to a stop and the driver continues to apply the brakes, as is customary in cars with an [[automatic transmission]], the pads will deposit a layer of material in the shape of the brake pad. This small thickness variation can begin the cycle of uneven pad transfer.		Thickness variation has many causes, but three primary mechanisms contribute to the propagation of disc thickness variations. The first is the improper selection of brake pads. Pads that are effective at low temperatures, such as when braking for the first time in cold weather, often are made of materials that decompose unevenly at higher temperatures. This uneven decomposition results in the uneven deposition of material onto the brake disc. Another cause of uneven material transfer is the improper break-in of a pad/disc combination. For proper break-in, the disc surface should be refreshed (either by machining the contact surface or by replacing the disc) every time the pads are changed. Once this is done, the brakes are heavily applied multiple times in succession. This creates a smooth, even interface between the pad and the disc. When this is not done properly the brake pads will see an uneven distribution of stress and heat, resulting in an uneven, seemingly random, deposition of pad material. The third primary mechanism of uneven pad material transfer is "pad imprinting." This occurs when the brake pads are heated to the point that the material begins to break down and transfer to the disc. In a properly broken-in brake system (with properly selected pads), this transfer is natural and is a major contributor to the braking force generated by the brake pads. However, if the vehicle comes to a stop and the driver continues to apply the brakes, as is customary in cars with an [[automatic transmission]], the pads will deposit a layer of material in the shape of the brake pad. This small thickness variation can begin the cycle of uneven pad transfer.{{Cn\|date=August 2024}}

	Once the disc has some level of variation in thickness, uneven pad deposition can accelerate, sometimes resulting in changes to the crystal structure of the metal that composes the disc. As the brakes are applied, the pads slide over the varying disc surface. As the pads pass by the thicker section of the disc, they are forced outwards. The foot of the driver applied to the brake pedal naturally resists this change, and thus more force is applied to the pads. The result is that the thicker sections see higher levels of stress. This causes uneven heating of the surface of the disc, which causes two major issues. As the brake disc heats unevenly it also expands unevenly. The thicker sections of the disc expand more than the thinner sections due to seeing more heat, and thus the difference in thickness is magnified. Also, the uneven distribution of heat results in the further uneven transfer of pad material. The result is that the thicker-hotter sections receive even more pad material than the thinner-cooler sections, contributing to a further increase in the variation in the disc's thickness. In extreme situations, this uneven heating can cause the crystal structure of the disc material to change. When the hotter sections of the discs reach extremely high temperatures ({{convert\|1200\|-\|1300\|°F\|°C\|disp=or}} <!-- {{convert\|1200\|-\|1300\|°F\|°C\|abbr=off\|disp=or}} -->), the metal can undergo a [[Phase transition\|phase transformation]] and the carbon which is dissolved in the steel can precipitate out to form carbon-heavy carbide regions known as [[cementite]]. This [[iron carbide]] is very different from the cast iron the rest of the disc is composed of. It is extremely hard, brittle, and does not absorb heat well. After cementite is formed, the integrity of the disc is compromised. Even if the disc surface is machined, the cementite within the disc will not wear or absorb heat at the same rate as the cast iron surrounding it, causing the uneven thickness and heating characteristics of the disc to return.		Once the disc has some level of variation in thickness, uneven pad deposition can accelerate, sometimes resulting in changes to the crystal structure of the metal that composes the disc. As the brakes are applied, the pads slide over the varying disc surface. As the pads pass by the thicker section of the disc, they are forced outwards. The foot of the driver applied to the brake pedal naturally resists this change, and thus more force is applied to the pads. The result is that the thicker sections see higher levels of stress. This causes uneven heating of the surface of the disc, which causes two major issues. As the brake disc heats unevenly it also expands unevenly. The thicker sections of the disc expand more than the thinner sections due to seeing more heat, and thus the difference in thickness is magnified. Also, the uneven distribution of heat results in the further uneven transfer of pad material. The result is that the thicker-hotter sections receive even more pad material than the thinner-cooler sections, contributing to a further increase in the variation in the disc's thickness. In extreme situations, this uneven heating can cause the crystal structure of the disc material to change. When the hotter sections of the discs reach extremely high temperatures ({{convert\|1200\|-\|1300\|°F\|°C\|disp=or}} <!-- {{convert\|1200\|-\|1300\|°F\|°C\|abbr=off\|disp=or}} -->), the metal can undergo a [[Phase transition\|phase transformation]] and the carbon which is dissolved in the steel can precipitate out to form carbon-heavy carbide regions known as [[cementite]]. This [[iron carbide]] is very different from the cast iron the rest of the disc is composed of. It is extremely hard, brittle, and does not absorb heat well. After cementite is formed, the integrity of the disc is compromised. Even if the disc surface is machined, the cementite within the disc will not wear or absorb heat at the same rate as the cast iron surrounding it, causing the uneven thickness and heating characteristics of the disc to return.{{Cn\|date=August 2024}}

	===Scarring===		===Scarring===
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	==Common problems==		==Common problems==
	{{Unreferenced section\|date=January 2016}}

	===Squeal===		===Squeal===
	Sometimes a loud noise or high-pitched squeal occurs when the brakes are applied. It mostly occurs on old [[car]]s and those who were produced or acquired some time ago. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs (known as ''force-coupled excitation''). This type of squeal should not negatively affect brake-stopping performance. Techniques include adding [[chamfer]] pads to the contact points between the caliper pistons and the pads, the bonding insulators (damping material) to the pad backplate, the brake shims between the brake pad and pistons, etc. All should be coated with an extremely high temperature, high solids lubricant to help reduce squeal. This allows the metal-to-metal parts to move independently of each other and thereby eliminate the buildup of energy that can create a frequency that is heard as brake squeal, groan, or growl. It is inherent that some pads are going to squeal more given the type of the pad and its usage case. Pads typically rated to withstand very high temperatures for extended periods tend to produce high amounts of friction leading to more noise during brake application.<ref name="Hawk"/>		Sometimes a loud noise or high-pitched squeal occurs when the brakes are applied. It mostly occurs on old [[car]]s and those who were produced or acquired some time ago. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs (known as ''force-coupled excitation''). This type of squeal should not negatively affect brake-stopping performance. Techniques include adding [[chamfer]] pads to the contact points between the caliper pistons and the pads, the bonding insulators (damping material) to the pad backplate, the brake shims between the brake pad and pistons, etc. All should be coated with an extremely high temperature, high solids lubricant to help reduce squeal. This allows the metal-to-metal parts to move independently of each other and thereby eliminate the buildup of energy that can create a frequency that is heard as brake squeal, groan, or growl. It is inherent that some pads are going to squeal more given the type of the pad and its usage case. Pads typically rated to withstand very high temperatures for extended periods tend to produce high amounts of friction leading to more noise during brake application.<ref name="Hawk"/>

	Cold weather combined with high early-morning humidity (dew) often worsens brake squeal. However, the squeal generally stops when the lining reaches regular operating temperatures. This more strongly affects pads meant to be used at higher temperatures. Dust on the brakes may also cause squeal and commercial brake cleaning products are designed to remove dirt and other contaminants. Pads without a proper amount of transfer material could also squeal, this can be remedied by bedding or re-bedding the brake pads to brake discs.		Cold weather combined with high early-morning humidity (dew) often worsens brake squeal. However, the squeal generally stops when the lining reaches regular operating temperatures. This more strongly affects pads meant to be used at higher temperatures. Dust on the brakes may also cause squeal and commercial brake cleaning products are designed to remove dirt and other contaminants. Pads without a proper amount of transfer material could also squeal, this can be remedied by bedding or re-bedding the brake pads to brake discs.{{Cn\|date=August 2024}}

	Some lining wear indicators, located either as a semi-metallic layer within the brake pad material or with an external "sensor", are also designed to squeal when the lining is due for replacement. The typical external sensor is fundamentally different from the noises described above (when the brakes are applied) because the wear sensor noise typically occurs when the brakes are not used. The wear sensor may only create a squeal under braking when it first begins to indicate wear but is still a fundamentally different sound and pitch.<ref name="Hawk"/><ref>Centric Parts, FAQ's 2010.</ref>		Some lining wear indicators, located either as a semi-metallic layer within the brake pad material or with an external "sensor", are also designed to squeal when the lining is due for replacement. The typical external sensor is fundamentally different from the noises described above (when the brakes are applied) because the wear sensor noise typically occurs when the brakes are not used. The wear sensor may only create a squeal under braking when it first begins to indicate wear but is still a fundamentally different sound and pitch.<ref name="Hawk"/><ref>Centric Parts, FAQ's 2010.</ref>

	===Judder or shimmy===		===Judder or shimmy===
	A brake judder is usually perceived by the driver as minor to severe vibrations transferred through the chassis during braking.<ref>Abdelahamid, M.K. (1997), "Brake judder analysis: Case studies", SAE, Technical Paper Series, no. 972027.</ref><ref>de Vries, A. et al. (1992), "The brake judder phenomenon", SAE Technical Paper Series, no. 920554.</ref><ref name=Engel>Engel, G.H. et al. (1994), "System approach to brake judder", SAE Technical Paper Series, no. 945041.</ref><ref>Gassmann, S. et al. (1993), "Excitation and transfer mechanism of brake judder", SAE Technical Paper Series, no. 931880.</ref><ref>Jacobsson, H. (1996), "High speed disc brake judder – the influence of passing through critical speed", In EuroMech – 2nd European Nonlinear Oscillations Conference, Prague, no. 2, pp. 75–78.</ref><ref>Jacobsson, H. (1997), "Wheel suspension related disc brake judder", ASME, no. DETC97/VIB-4165, pp. 1–10.</ref><ref>Jacobsson, H. (1998), "Frequency Sweep Approach to Brake Judder, Licentiate of engineering", Chalmers University of Technology Sweden.</ref><ref>Jacobsson, H. (1999), SAE Technical Paper Series, no. 1999-01-1779, pp. 1–14.</ref><ref>Stringham, W. et al. (1993), "Brake roughness – disc brake torque variation", disc distortion and vehicle response, SAE Technical Paper Series, no. 930803.</ref>		A brake judder is usually perceived by the driver as minor to severe vibrations transferred through the chassis during braking.<ref>Abdelahamid, M.K. (1997), "Brake judder analysis: Case studies", SAE, Technical Paper Series, no. 972027.</ref><ref>de Vries, A. et al. (1992), "The brake judder phenomenon", SAE Technical Paper Series, no. 920554.</ref><ref name=Engel>Engel, G.H. et al. (1994), "System approach to brake judder", SAE Technical Paper Series, no. 945041.</ref><ref>Gassmann, S. et al. (1993), "Excitation and transfer mechanism of brake judder", SAE Technical Paper Series, no. 931880.</ref><ref>Jacobsson, H. (1996), "High speed disc brake judder – the influence of passing through critical speed", In EuroMech – 2nd European Nonlinear Oscillations Conference, Prague, no. 2, pp. 75–78.</ref><ref>Jacobsson, H. (1997), "Wheel suspension related disc brake judder", ASME, no. DETC97/VIB-4165, pp. 1–10.</ref><ref>Jacobsson, H. (1998), "Frequency Sweep Approach to Brake Judder, Licentiate of engineering", Chalmers University of Technology Sweden.</ref><ref>Jacobsson, H. (1999), SAE Technical Paper Series, no. 1999-01-1779, pp. 1–14.</ref><ref>Stringham, W. et al. (1993), "Brake roughness – disc brake torque variation", disc distortion and vehicle response, SAE Technical Paper Series, no. 930803.</ref>{{Excessive citations inline\|date=August 2024}}

	The judder phenomenon can be classified into two distinct subgroups: ''hot'' (or ''thermal''), or ''cold'' judder.		The judder phenomenon can be classified into two distinct subgroups: ''hot'' (or ''thermal''), or ''cold'' judder.

GraemeLeggett: /* Design */ cites needed

2024-08-13T07:26:02Z

Design: cites needed

Citation bot: Added date. Removed parameters. | Use this bot. Report bugs. | Suggested by Abductive | Category:Railway brakes | #UCB_Category 13/24

2024-08-05T06:31:23Z

Added date. Removed parameters. | Use this bot. Report bugs. | Suggested by Abductive | Category:Railway brakes | #UCB_Category 13/24

← Previous revision		Revision as of 06:31, 5 August 2024
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	[[File:Disk brake dsc03682.jpg\|thumb\|Close-up of a disc brake on a [[Renault]] car]]		[[File:Disk brake dsc03682.jpg\|thumb\|Close-up of a disc brake on a [[Renault]] car]]

	A '''disc brake''' is a type of [[brake]] that uses the [[#Calipers\|calipers]] to squeeze pairs of [[#Brake pads\|pads]] against a disc or a rotor<ref>{{cite web\|last=Deaton \|first=Jamie Page \|title=How Brake Rotors Work \|url= https://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors.htm \|publisher=HowStuffWorks \|date=11 November 2008 \|access-date=26 November 2017}}</ref> to create [[friction]].<ref>{{cite encyclopedia \|title=Disc brake \|url= https://www.merriam-webster.com/dictionary/disc%20brake \|dictionary=Merriam-Webster Dictionary \|date=16 November 2017 \|access-date=26 November 2017}}</ref> There are two basic types of brake pad friction mechanisms: abrasive friction and adherent friction. <ref>{{Cite web \|year=2023 \|title=Abrasive friction and adherent friction \|url=https://www.centricparts.com/media/wysiwyg/technical-bulletins/TECH_BULLETIN_C22-01.pdf \|website=Centricparts \|page=1 ~~\|format=PDF~~}}</ref> This action slows the rotation of a shaft, such as a [[vehicle]] [[axle]], either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into [[heat]], which must be dispersed.		A '''disc brake''' is a type of [[brake]] that uses the [[#Calipers\|calipers]] to squeeze pairs of [[#Brake pads\|pads]] against a disc or a rotor<ref>{{cite web\|last=Deaton \|first=Jamie Page \|title=How Brake Rotors Work \|url= https://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors.htm \|publisher=HowStuffWorks \|date=11 November 2008 \|access-date=26 November 2017}}</ref> to create [[friction]].<ref>{{cite encyclopedia \|title=Disc brake \|url= https://www.merriam-webster.com/dictionary/disc%20brake \|dictionary=Merriam-Webster Dictionary \|date=16 November 2017 \|access-date=26 November 2017}}</ref> There are two basic types of brake pad friction mechanisms: abrasive friction and adherent friction. <ref>{{Cite web \|year=2023 \|title=Abrasive friction and adherent friction \|url=https://www.centricparts.com/media/wysiwyg/technical-bulletins/TECH_BULLETIN_C22-01.pdf \|website=Centricparts \|page=1 }}</ref> This action slows the rotation of a shaft, such as a [[vehicle]] [[axle]], either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into [[heat]], which must be dispersed.

	[[Hydraulic brakes\|Hydraulically]] [[Actuator\|actuated]] disc brakes are the most commonly used mechanical device for slowing motor vehicles. The principles of a disc brake apply to almost any rotating shaft. The components include the disc, [[master cylinder]], and caliper, which contain at least one cylinder and two [[Brake pad\|brake pads]] on both sides of the rotating disc.		[[Hydraulic brakes\|Hydraulically]] [[Actuator\|actuated]] disc brakes are the most commonly used mechanical device for slowing motor vehicles. The principles of a disc brake apply to almost any rotating shaft. The components include the disc, [[master cylinder]], and caliper, which contain at least one cylinder and two [[Brake pad\|brake pads]] on both sides of the rotating disc.
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	[[File:Tōkyū 7000 series EMU 011.JPG\|thumb\|A railroad [[bogie]] and disc brakes]]		[[File:Tōkyū 7000 series EMU 011.JPG\|thumb\|A railroad [[bogie]] and disc brakes]]

	Still-larger discs are used for [[railroad car]]s, [[tram]]s, and some [[airplane]]s. [[Passenger car (rail)\|Passenger rail cars]] and [[light rail vehicle]]s often use disc brakes outboard of the wheels, which helps ensure a free flow of cooling air. Some modern passenger rail cars, such as the [[Amfleet\|Amfleet II cars]], use inboard disc brakes. This reduces wear from debris and provides protection from rain and snow, which would make the discs slippery and unreliable. However, there is still plenty of cooling for reliable operation. Some airplanes have the brake mounted with very little cooling, and the brake gets hot when stopping. This is acceptable as there is sufficient time for cooling, where the maximum braking energy is very predictable. Should the braking energy exceed the maximum, for example during an emergency occurring during take-off, aircraft wheels can be fitted with a [[fusible plug]]<ref>{{cite web\|url= https://patents.google.com/patent/US4628953A/en \|title= Fusible plug safety device for venting aircraft tires}}</ref> to prevent the tire bursting. This is a milestone test in aircraft development.<ref>{{cite web\|url= https://www.airbus.com/newsroom/press-releases/en/2014/07/a350-xwb-msn001-successfully-conducted-maximum-energy-rejected-take-off-test.html \|title=A350 XWB MSN001 successfully conducted 'Maximum Energy Rejected Take-Off' test}}</ref>		Still-larger discs are used for [[railroad car]]s, [[tram]]s, and some [[airplane]]s. [[Passenger car (rail)\|Passenger rail cars]] and [[light rail vehicle]]s often use disc brakes outboard of the wheels, which helps ensure a free flow of cooling air. Some modern passenger rail cars, such as the [[Amfleet\|Amfleet II cars]], use inboard disc brakes. This reduces wear from debris and provides protection from rain and snow, which would make the discs slippery and unreliable. However, there is still plenty of cooling for reliable operation. Some airplanes have the brake mounted with very little cooling, and the brake gets hot when stopping. This is acceptable as there is sufficient time for cooling, where the maximum braking energy is very predictable. Should the braking energy exceed the maximum, for example during an emergency occurring during take-off, aircraft wheels can be fitted with a [[fusible plug]]<ref>{{cite web\|url= https://patents.google.com/patent/US4628953A/en \|title= Fusible plug safety device for venting aircraft tires}}</ref> to prevent the tire bursting. This is a milestone test in aircraft development.<ref>{{cite web\|url= https://www.airbus.com/newsroom/press-releases/en/2014/07/a350-xwb-msn001-successfully-conducted-maximum-energy-rejected-take-off-test.html \|title=A350 XWB MSN001 successfully conducted 'Maximum Energy Rejected Take-Off' test\|date=14 June 2021 }}</ref>

	=== Automotive use ===		=== Automotive use ===

OldsVistaCruiser: /* Scarring */Added content

2024-07-27T17:30:52Z

Scarring: Added content

← Previous revision		Revision as of 17:30, 27 July 2024
Line 162:		Line 162:
	Scarring (US: Scoring) can occur if brake pads are not changed promptly when they reach the end of their service life and are considered worn out. Once enough of the friction material has worn away, the pad's steel backing plate (for glued pads) or the pad retainer rivets (for riveted pads) will bear upon the disc's wear surface, reducing braking power and making scratches on the disc. Generally, a moderately scarred or scored disc, which operated satisfactorily with existing brake pads, will be equally usable with new pads. If the scarring is deeper but not excessive, it can be repaired by machining off a layer of the disc's surface. This can only be done a limited number of times as the disc has a minimum rated safe thickness. The minimum thickness value is typically cast into the disc during manufacturing on the hub or the edge of the disc. In [[Pennsylvania]], which has one of the most rigorous auto safety inspection programs in North America, an automotive disc cannot pass a safety inspection if any scoring is deeper than {{convert\|.015\|in\|mm}}, and must be replaced if machining will reduce the disc below its minimum safe thickness.		Scarring (US: Scoring) can occur if brake pads are not changed promptly when they reach the end of their service life and are considered worn out. Once enough of the friction material has worn away, the pad's steel backing plate (for glued pads) or the pad retainer rivets (for riveted pads) will bear upon the disc's wear surface, reducing braking power and making scratches on the disc. Generally, a moderately scarred or scored disc, which operated satisfactorily with existing brake pads, will be equally usable with new pads. If the scarring is deeper but not excessive, it can be repaired by machining off a layer of the disc's surface. This can only be done a limited number of times as the disc has a minimum rated safe thickness. The minimum thickness value is typically cast into the disc during manufacturing on the hub or the edge of the disc. In [[Pennsylvania]], which has one of the most rigorous auto safety inspection programs in North America, an automotive disc cannot pass a safety inspection if any scoring is deeper than {{convert\|.015\|in\|mm}}, and must be replaced if machining will reduce the disc below its minimum safe thickness.

	To prevent scarring, it is prudent to periodically inspect the brake pads for wear. A tire rotation is a logical time for inspection, since rotation must be performed regularly based on vehicle operation time and all wheels must be removed, allowing ready visual access to the brake pads. Some types of alloy wheels and brake arrangements will provide enough open space to view the pads without removing the wheel. When practical, pads that are near the wear-out point should be replaced immediately, as complete wear-out leads to scarring damage and unsafe braking. Many disc brake pads will include some sort of soft steel spring or drag tab as part of the pad assembly, which drags on the disc when the pad is nearly worn out. This produces a moderately loud squealing noise, alerting the driver that service is required. This will not normally scar the disc if the brakes are serviced promptly. A set of pads can be considered for replacement if the thickness of the pad material is the same or less than the thickness of the backing steel. In Pennsylvania, the standard is {{Convert\|1/32\|inch\|mm}} for ~~bonded~~ pads and 2/32" for ~~riveted~~ pads.		To prevent scarring, it is prudent to periodically inspect the brake pads for wear. A tire rotation is a logical time for inspection, since rotation must be performed regularly based on vehicle operation time and all wheels must be removed, allowing ready visual access to the brake pads. Some types of alloy wheels and brake arrangements will provide enough open space to view the pads without removing the wheel. When practical, pads that are near the wear-out point should be replaced immediately, as complete wear-out leads to scarring damage and unsafe braking. Many disc brake pads will include some sort of soft steel spring or drag tab as part of the pad assembly, which drags on the disc when the pad is nearly worn out. This produces a moderately loud squealing noise, alerting the driver that service is required. This will not normally scar the disc if the brakes are serviced promptly. A set of pads can be considered for replacement if the thickness of the pad material is the same or less than the thickness of the backing steel. In Pennsylvania, the standard is {{Convert\|1/32\|inch\|mm}} for riveted pads and 2/32" for bonded pads.

	===Cracking===		===Cracking===

OldsVistaCruiser: /* Scarring */

2024-07-27T17:29:41Z

Scarring

← Previous revision		Revision as of 17:29, 27 July 2024
Line 162:		Line 162:
	Scarring (US: Scoring) can occur if brake pads are not changed promptly when they reach the end of their service life and are considered worn out. Once enough of the friction material has worn away, the pad's steel backing plate (for glued pads) or the pad retainer rivets (for riveted pads) will bear upon the disc's wear surface, reducing braking power and making scratches on the disc. Generally, a moderately scarred or scored disc, which operated satisfactorily with existing brake pads, will be equally usable with new pads. If the scarring is deeper but not excessive, it can be repaired by machining off a layer of the disc's surface. This can only be done a limited number of times as the disc has a minimum rated safe thickness. The minimum thickness value is typically cast into the disc during manufacturing on the hub or the edge of the disc. In [[Pennsylvania]], which has one of the most rigorous auto safety inspection programs in North America, an automotive disc cannot pass a safety inspection if any scoring is deeper than {{convert\|.015\|in\|mm}}, and must be replaced if machining will reduce the disc below its minimum safe thickness.		Scarring (US: Scoring) can occur if brake pads are not changed promptly when they reach the end of their service life and are considered worn out. Once enough of the friction material has worn away, the pad's steel backing plate (for glued pads) or the pad retainer rivets (for riveted pads) will bear upon the disc's wear surface, reducing braking power and making scratches on the disc. Generally, a moderately scarred or scored disc, which operated satisfactorily with existing brake pads, will be equally usable with new pads. If the scarring is deeper but not excessive, it can be repaired by machining off a layer of the disc's surface. This can only be done a limited number of times as the disc has a minimum rated safe thickness. The minimum thickness value is typically cast into the disc during manufacturing on the hub or the edge of the disc. In [[Pennsylvania]], which has one of the most rigorous auto safety inspection programs in North America, an automotive disc cannot pass a safety inspection if any scoring is deeper than {{convert\|.015\|in\|mm}}, and must be replaced if machining will reduce the disc below its minimum safe thickness.

	To prevent scarring, it is prudent to periodically inspect the brake pads for wear. A tire rotation is a logical time for inspection, since rotation must be performed regularly based on vehicle operation time and all wheels must be removed, allowing ready visual access to the brake pads. Some types of alloy wheels and brake arrangements will provide enough open space to view the pads without removing the wheel. When practical, pads that are near the wear-out point should be replaced immediately, as complete wear-out leads to scarring damage and unsafe braking. Many disc brake pads will include some sort of soft steel spring or drag tab as part of the pad assembly, which drags on the disc when the pad is nearly worn out. This produces a moderately loud squealing noise, alerting the driver that service is required. This will not normally scar the disc if the brakes are serviced promptly. A set of pads can be considered for replacement if the thickness of the pad material is the same or less than the thickness of the backing steel. In Pennsylvania, the standard is 1/~~32″~~.		To prevent scarring, it is prudent to periodically inspect the brake pads for wear. A tire rotation is a logical time for inspection, since rotation must be performed regularly based on vehicle operation time and all wheels must be removed, allowing ready visual access to the brake pads. Some types of alloy wheels and brake arrangements will provide enough open space to view the pads without removing the wheel. When practical, pads that are near the wear-out point should be replaced immediately, as complete wear-out leads to scarring damage and unsafe braking. Many disc brake pads will include some sort of soft steel spring or drag tab as part of the pad assembly, which drags on the disc when the pad is nearly worn out. This produces a moderately loud squealing noise, alerting the driver that service is required. This will not normally scar the disc if the brakes are serviced promptly. A set of pads can be considered for replacement if the thickness of the pad material is the same or less than the thickness of the backing steel. In Pennsylvania, the standard is {{Convert\|1/32\|inch\|mm}} for bonded pads and 2/32" for riveted pads.

	===Cracking===		===Cracking===

184.96.194.142: /* Bicycles */

2024-06-25T18:14:10Z

Bicycles

← Previous revision		Revision as of 18:14, 25 June 2024
Line 101:		Line 101:
	[[File:Santa Cruz 2013 Tallboy Al 11.jpg\|thumb\|upright\|Rear disc brake caliper and disc on a mountain bike]]		[[File:Santa Cruz 2013 Tallboy Al 11.jpg\|thumb\|upright\|Rear disc brake caliper and disc on a mountain bike]]

	[[Bicycle\|Bike]] disc brakes may range from simple, mechanical (cable) systems, to expensive and powerful, multi-piston hydraulic disc systems, commonly used on [[Downhill mountain biking\|downhill racing bikes]]. Improved technology has seen the creation of vented discs for use on [[Mountain bike\|mountain bikes]], similar to those on cars, introduced to help avoid [[Brake fade\|heat fade]] on fast alpine descents. ~~Although less common, discs~~ are also used on [[Road bicycle\|road bicycles]] for all-weather cycling with predictable braking, ~~although~~ ~~drums~~ are sometimes preferred as harder to damage in crowded parking, where discs are sometimes bent. Most bicycle brake discs are made of steel. Stainless steel is preferred due to its anti-rust properties.<ref>{{cite book\|title=Sutherland's Handbook for Bicycle Mechanics Chapter 11 - Brakes \|first=Howard \|last=Sutherland \|page=13 \|year=2004 \|edition=7th \|publisher=Sutherland's Bicycle Shop Aids \|url= http://www.sutherlandsbicycle.com/Chapter11.pdf \|archive-url= https://web.archive.org/web/20131014223452/http://www.sutherlandsbicycle.com/Chapter11.pdf \|archive-date=14 October 2013 \|access-date=15 February 2015}}</ref> Discs are thin, often about 2 mm. Some use a two-piece floating disc style, others use a one-piece solid metal disc. Bicycle disc brakes use either a two-piston caliper that clamps the disc from both sides or a single-piston caliper with one moving pad that contacts the disc first, and then pushes the disc against the non-moving pad.<ref>{{cite web \|title=Mechanical Road Disc Brake Roundup \|work=Gravelbike \|date=10 September 2016 \|url=https://www.gravelbike.com/mechanical-road-disc-brake-roundup/ \|access-date=2021-03-30 \|language=en-US \|archive-date=1 March 2021 \|archive-url=https://web.archive.org/web/20210301100458/https://www.gravelbike.com/mechanical-road-disc-brake-roundup/ \|url-status=dead }}</ref> Because energy efficiency is so important in bicycles, an uncommon feature of bicycle brakes is that the pads retract to eliminate residual drag when the brake is released.{{Clarify\|date=May 2017\|reason=Don't brake pads retract slightly for all types of disc brakes?}} In contrast, most other brakes drag the pads lightly when released to minimize initial operational travel.{{Clarify\|date=May 2017\|reason=Brake pads usually drag slightly in other applications?}}		[[Bicycle\|Bike]] disc brakes may range from simple, mechanical (cable) systems, to expensive and powerful, multi-piston hydraulic disc systems, commonly used on [[Downhill mountain biking\|downhill racing bikes]]. Improved technology has seen the creation of vented discs for use on [[Mountain bike\|mountain bikes]], similar to those on cars, introduced to help avoid [[Brake fade\|heat fade]] on fast alpine descents. Discs are also used on [[Road bicycle\|road bicycles]] for all-weather cycling with predictable braking. By 2024, almost all road bikes are equipped with disc brakes, just like Mountain bikes. Drums are sometimes preferred as harder to damage in crowded parking, where discs are sometimes bent. Most bicycle brake discs are made of steel. Stainless steel is preferred due to its anti-rust properties.<ref>{{cite book\|title=Sutherland's Handbook for Bicycle Mechanics Chapter 11 - Brakes \|first=Howard \|last=Sutherland \|page=13 \|year=2004 \|edition=7th \|publisher=Sutherland's Bicycle Shop Aids \|url= http://www.sutherlandsbicycle.com/Chapter11.pdf \|archive-url= https://web.archive.org/web/20131014223452/http://www.sutherlandsbicycle.com/Chapter11.pdf \|archive-date=14 October 2013 \|access-date=15 February 2015}}</ref> Discs are thin, often about 2 mm. Some use a two-piece floating disc style, others use a one-piece solid metal disc. Bicycle disc brakes use either a two-piston caliper that clamps the disc from both sides or a single-piston caliper with one moving pad that contacts the disc first, and then pushes the disc against the non-moving pad.<ref>{{cite web \|title=Mechanical Road Disc Brake Roundup \|work=Gravelbike \|date=10 September 2016 \|url=https://www.gravelbike.com/mechanical-road-disc-brake-roundup/ \|access-date=2021-03-30 \|language=en-US \|archive-date=1 March 2021 \|archive-url=https://web.archive.org/web/20210301100458/https://www.gravelbike.com/mechanical-road-disc-brake-roundup/ \|url-status=dead }}</ref> Because energy efficiency is so important in bicycles, an uncommon feature of bicycle brakes is that the pads retract to eliminate residual drag when the brake is released.{{Clarify\|date=May 2017\|reason=Don't brake pads retract slightly for all types of disc brakes?}} In contrast, most other brakes drag the pads lightly when released to minimize initial operational travel.{{Clarify\|date=May 2017\|reason=Brake pads usually drag slightly in other applications?}}

	===Heavy vehicles===		===Heavy vehicles===

InternetArchiveBot: Rescuing 1 sources and tagging 0 as dead.) #IABot (v2.0.9.5

2024-06-09T23:16:17Z

Rescuing 1 sources and tagging 0 as dead.) #IABot (v2.0.9.5

← Previous revision		Revision as of 23:16, 9 June 2024
Line 76:		Line 76:

	===In the U.S.===		===In the U.S.===
	In 1963, the [[Studebaker Avanti]] was factory-equipped with front disc brakes as standard equipment.<ref name="cv">{{cite web \|url= http://www.pointhappy.com/cvcars/avanti.htm \|title=The Avanti — Born in Palm Springs \|publisher=Point Happy Interactive \|access-date=14 December 2015}}</ref> This [[Bendix Corporation\|Bendix]] system licensed from Dunlop was also optional on some of the other Studebaker models.<ref>{{cite web\|title=1963–1964 Studebaker Avanti\|url= http://auto.howstuffworks.com/1963-1964-studebaker-avanti.htm \|website=How Stuff Works \|date=17 December 2007 \|access-date=14 December 2015}}</ref> Front disc brakes became standard equipment on the 1965 [[Rambler Marlin]].<ref>{{cite web\|title=Introduction to the 1965–1967 AMC Marlin \|url= http://auto.howstuffworks.com/1965-1967-amc-marlin.htm/printable \|website=How Stuff Works \|date=26 October 2007 \|access-date=14 December 2015}}</ref> The Bendix units were optional on all [[American Motors]]' [[Rambler Classic]] and [[AMC Ambassador\|Ambassador]] models as well as on the [[Ford Thunderbird (fourth generation)\|Ford Thunderbird]], and the [[Lincoln Continental]].<ref name="whatsnewAMC">{{cite magazine \|title=What's new at American Motors \|magazine=Popular Science \|volume=185 \|issue=4 \|pages=90–91 \|date=October 1964 \|url= https://books.google.com/books?id=1yUDAAAAMBAJ&q=What's+new+at+American+Motors+1965&pg=PA90 \|access-date=14 December 2015}}</ref><ref>{{cite book\|last=Long \|first=Brian \|title=The Book of the Ford Thunderbird from 1954 \|year=2007 \|publisher=Veloce Publishing \|isbn=978-1-904788-47-8\|url= https://books.google.com/books?id=6Xrl9QmUyRAC&q=disc+brakes+1965+Ford+Thunderbird&pg=PA104 \|page=104 \|access-date=11 November 2010}}</ref><ref>{{cite web\|title=1964–1965 Lincoln Continental\|url= http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|website=How Stuff Works\|date=27 November 2007\|access-date=14 December 2015\|archive-date=12 June 2011\|archive-url= https://web.archive.org/web/20110612180708/http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|url-status=dead}}</ref> A four-wheel disc brake system was also introduced in 1965 on the [[Chevrolet Corvette (C2)\|Chevrolet Corvette]] Stingray.<ref>{{cite web\|title=1965 Corvette\|url= http://auto.howstuffworks.com/1965-corvette.htm \|website=How Stuff Works \|date=14 December 2015 \|access-date=14 December 2015}}</ref> Most U.S. cars switched from front drum brakes to front disk brakes in the late 1970s and early 1980s.		In 1963, the [[Studebaker Avanti]] was factory-equipped with front disc brakes as standard equipment.<ref name="cv">{{cite web \|url= http://www.pointhappy.com/cvcars/avanti.htm \|title=The Avanti — Born in Palm Springs \|publisher=Point Happy Interactive \|access-date=14 December 2015}}</ref> This [[Bendix Corporation\|Bendix]] system licensed from Dunlop was also optional on some of the other Studebaker models.<ref>{{cite web\|title=1963–1964 Studebaker Avanti\|url= http://auto.howstuffworks.com/1963-1964-studebaker-avanti.htm \|website=How Stuff Works \|date=17 December 2007 \|access-date=14 December 2015}}</ref> Front disc brakes became standard equipment on the 1965 [[Rambler Marlin]].<ref>{{cite web\|title=Introduction to the 1965–1967 AMC Marlin \|url= http://auto.howstuffworks.com/1965-1967-amc-marlin.htm/printable \|website=How Stuff Works \|date=26 October 2007 \|access-date=14 December 2015}}</ref> The Bendix units were optional on all [[American Motors]]' [[Rambler Classic]] and [[AMC Ambassador\|Ambassador]] models as well as on the [[Ford Thunderbird (fourth generation)\|Ford Thunderbird]], and the [[Lincoln Continental]].<ref name="whatsnewAMC">{{cite magazine \|title=What's new at American Motors \|magazine=Popular Science \|volume=185 \|issue=4 \|pages=90–91 \|date=October 1964 \|url= https://books.google.com/books?id=1yUDAAAAMBAJ&q=What's+new+at+American+Motors+1965&pg=PA90 \|access-date=14 December 2015}}</ref><ref>{{cite book\|last=Long \|first=Brian \|title=The Book of the Ford Thunderbird from 1954 \|year=2007 \|publisher=Veloce Publishing \|isbn=978-1-904788-47-8\|url= https://books.google.com/books?id=6Xrl9QmUyRAC&q=disc+brakes+1965+Ford+Thunderbird&pg=PA104 \|page=104 \|access-date=11 November 2010}}</ref><ref>{{cite web\|title=1964–1965 Lincoln Continental\|url= http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|website=How Stuff Works\|date=27 November 2007\|access-date=14 December 2015\|archive-date=12 June 2011\|archive-url= https://web.archive.org/web/20110612180708/http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|url-status=dead}}</ref> A four-wheel disc brake system was also introduced in 1965 on the [[Chevrolet Corvette (C2)\|Chevrolet Corvette]] Stingray.<ref>{{cite web\|title=1965 Corvette\|url=http://auto.howstuffworks.com/1965-corvette.htm\|website=How Stuff Works\|date=14 December 2015\|access-date=14 December 2015\|archive-date=12 June 2011\|archive-url=https://web.archive.org/web/20110612173401/http://auto.howstuffworks.com/1965-corvette.htm\|url-status=dead}}</ref> Most U.S. cars switched from front drum brakes to front disk brakes in the late 1970s and early 1980s.

	===Motorcycles and scooters===		===Motorcycles and scooters===

2605:59C8:7C7:7210:2FCA:41AD:6E09:D5D3: /* In the U.S. */

2024-05-09T21:01:19Z

In the U.S.

← Previous revision		Revision as of 21:01, 9 May 2024
Line 76:		Line 76:

	===In the U.S.===		===In the U.S.===
	In 1963, the [[Studebaker Avanti]] was factory-equipped with front disc brakes as standard equipment.<ref name="cv">{{cite web \|url= http://www.pointhappy.com/cvcars/avanti.htm \|title=The Avanti — Born in Palm Springs \|publisher=Point Happy Interactive \|access-date=14 December 2015}}</ref> This [[Bendix Corporation\|Bendix]] system licensed from ~~Dulop~~ was also optional on some of the other Studebaker models.<ref>{{cite web\|title=1963–1964 Studebaker Avanti\|url= http://auto.howstuffworks.com/1963-1964-studebaker-avanti.htm \|website=How Stuff Works \|date=17 December 2007 \|access-date=14 December 2015}}</ref> Front disc brakes became standard equipment on the 1965 [[Rambler Marlin]].<ref>{{cite web\|title=Introduction to the 1965–1967 AMC Marlin \|url= http://auto.howstuffworks.com/1965-1967-amc-marlin.htm/printable \|website=How Stuff Works \|date=26 October 2007 \|access-date=14 December 2015}}</ref> The Bendix units were optional on all [[American Motors]]' [[Rambler Classic]] and [[AMC Ambassador\|Ambassador]] models as well as on the [[Ford Thunderbird (fourth generation)\|Ford Thunderbird]], and the [[Lincoln Continental]].<ref name="whatsnewAMC">{{cite magazine \|title=What's new at American Motors \|magazine=Popular Science \|volume=185 \|issue=4 \|pages=90–91 \|date=October 1964 \|url= https://books.google.com/books?id=1yUDAAAAMBAJ&q=What's+new+at+American+Motors+1965&pg=PA90 \|access-date=14 December 2015}}</ref><ref>{{cite book\|last=Long \|first=Brian \|title=The Book of the Ford Thunderbird from 1954 \|year=2007 \|publisher=Veloce Publishing \|isbn=978-1-904788-47-8\|url= https://books.google.com/books?id=6Xrl9QmUyRAC&q=disc+brakes+1965+Ford+Thunderbird&pg=PA104 \|page=104 \|access-date=11 November 2010}}</ref><ref>{{cite web\|title=1964–1965 Lincoln Continental\|url= http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|website=How Stuff Works\|date=27 November 2007\|access-date=14 December 2015\|archive-date=12 June 2011\|archive-url= https://web.archive.org/web/20110612180708/http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|url-status=dead}}</ref> A four-wheel disc brake system was also introduced in 1965 on the [[Chevrolet Corvette (C2)\|Chevrolet Corvette]] Stingray.<ref>{{cite web\|title=1965 Corvette\|url= http://auto.howstuffworks.com/1965-corvette.htm \|website=How Stuff Works \|date=14 December 2015 \|access-date=14 December 2015}}</ref> Most U.S. cars switched from front drum brakes to front disk brakes in the late 1970s and early 1980s.		In 1963, the [[Studebaker Avanti]] was factory-equipped with front disc brakes as standard equipment.<ref name="cv">{{cite web \|url= http://www.pointhappy.com/cvcars/avanti.htm \|title=The Avanti — Born in Palm Springs \|publisher=Point Happy Interactive \|access-date=14 December 2015}}</ref> This [[Bendix Corporation\|Bendix]] system licensed from Dunlop was also optional on some of the other Studebaker models.<ref>{{cite web\|title=1963–1964 Studebaker Avanti\|url= http://auto.howstuffworks.com/1963-1964-studebaker-avanti.htm \|website=How Stuff Works \|date=17 December 2007 \|access-date=14 December 2015}}</ref> Front disc brakes became standard equipment on the 1965 [[Rambler Marlin]].<ref>{{cite web\|title=Introduction to the 1965–1967 AMC Marlin \|url= http://auto.howstuffworks.com/1965-1967-amc-marlin.htm/printable \|website=How Stuff Works \|date=26 October 2007 \|access-date=14 December 2015}}</ref> The Bendix units were optional on all [[American Motors]]' [[Rambler Classic]] and [[AMC Ambassador\|Ambassador]] models as well as on the [[Ford Thunderbird (fourth generation)\|Ford Thunderbird]], and the [[Lincoln Continental]].<ref name="whatsnewAMC">{{cite magazine \|title=What's new at American Motors \|magazine=Popular Science \|volume=185 \|issue=4 \|pages=90–91 \|date=October 1964 \|url= https://books.google.com/books?id=1yUDAAAAMBAJ&q=What's+new+at+American+Motors+1965&pg=PA90 \|access-date=14 December 2015}}</ref><ref>{{cite book\|last=Long \|first=Brian \|title=The Book of the Ford Thunderbird from 1954 \|year=2007 \|publisher=Veloce Publishing \|isbn=978-1-904788-47-8\|url= https://books.google.com/books?id=6Xrl9QmUyRAC&q=disc+brakes+1965+Ford+Thunderbird&pg=PA104 \|page=104 \|access-date=11 November 2010}}</ref><ref>{{cite web\|title=1964–1965 Lincoln Continental\|url= http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|website=How Stuff Works\|date=27 November 2007\|access-date=14 December 2015\|archive-date=12 June 2011\|archive-url= https://web.archive.org/web/20110612180708/http://auto.howstuffworks.com/1964-1965-lincoln-continental.htm/printable\|url-status=dead}}</ref> A four-wheel disc brake system was also introduced in 1965 on the [[Chevrolet Corvette (C2)\|Chevrolet Corvette]] Stingray.<ref>{{cite web\|title=1965 Corvette\|url= http://auto.howstuffworks.com/1965-corvette.htm \|website=How Stuff Works \|date=14 December 2015 \|access-date=14 December 2015}}</ref> Most U.S. cars switched from front drum brakes to front disk brakes in the late 1970s and early 1980s.

	===Motorcycles and scooters===		===Motorcycles and scooters===

← Previous revision		Revision as of 06:31, 5 August 2024
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	[[File:Disk brake dsc03682.jpg\|thumb\|Close-up of a disc brake on a [[Renault]] car]]		[[File:Disk brake dsc03682.jpg\|thumb\|Close-up of a disc brake on a [[Renault]] car]]

	A '''disc brake''' is a type of [[brake]] that uses the [[#Calipers\|calipers]] to squeeze pairs of [[#Brake pads\|pads]] against a disc or a rotor<ref>{{cite web\|last=Deaton \|first=Jamie Page \|title=How Brake Rotors Work \|url= https://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors.htm \|publisher=HowStuffWorks \|date=11 November 2008 \|access-date=26 November 2017}}</ref> to create [[friction]].<ref>{{cite encyclopedia \|title=Disc brake \|url= https://www.merriam-webster.com/dictionary/disc%20brake \|dictionary=Merriam-Webster Dictionary \|date=16 November 2017 \|access-date=26 November 2017}}</ref> There are two basic types of brake pad friction mechanisms: abrasive friction and adherent friction. <ref>{{Cite web \|year=2023 \|title=Abrasive friction and adherent friction \|url=https://www.centricparts.com/media/wysiwyg/technical-bulletins/TECH_BULLETIN_C22-01.pdf \|website=Centricparts \|page=1 ~~\|format=PDF~~}}</ref> This action slows the rotation of a shaft, such as a [[vehicle]] [[axle]], either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into [[heat]], which must be dispersed.		A '''disc brake''' is a type of [[brake]] that uses the [[#Calipers\|calipers]] to squeeze pairs of [[#Brake pads\|pads]] against a disc or a rotor<ref>{{cite web\|last=Deaton \|first=Jamie Page \|title=How Brake Rotors Work \|url= https://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors.htm \|publisher=HowStuffWorks \|date=11 November 2008 \|access-date=26 November 2017}}</ref> to create [[friction]].<ref>{{cite encyclopedia \|title=Disc brake \|url= https://www.merriam-webster.com/dictionary/disc%20brake \|dictionary=Merriam-Webster Dictionary \|date=16 November 2017 \|access-date=26 November 2017}}</ref> There are two basic types of brake pad friction mechanisms: abrasive friction and adherent friction. <ref>{{Cite web \|year=2023 \|title=Abrasive friction and adherent friction \|url=https://www.centricparts.com/media/wysiwyg/technical-bulletins/TECH_BULLETIN_C22-01.pdf \|website=Centricparts \|page=1 }}</ref> This action slows the rotation of a shaft, such as a [[vehicle]] [[axle]], either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into [[heat]], which must be dispersed.

	[[Hydraulic brakes\|Hydraulically]] [[Actuator\|actuated]] disc brakes are the most commonly used mechanical device for slowing motor vehicles. The principles of a disc brake apply to almost any rotating shaft. The components include the disc, [[master cylinder]], and caliper, which contain at least one cylinder and two [[Brake pad\|brake pads]] on both sides of the rotating disc.		[[Hydraulic brakes\|Hydraulically]] [[Actuator\|actuated]] disc brakes are the most commonly used mechanical device for slowing motor vehicles. The principles of a disc brake apply to almost any rotating shaft. The components include the disc, [[master cylinder]], and caliper, which contain at least one cylinder and two [[Brake pad\|brake pads]] on both sides of the rotating disc.
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	[[File:Tōkyū 7000 series EMU 011.JPG\|thumb\|A railroad [[bogie]] and disc brakes]]		[[File:Tōkyū 7000 series EMU 011.JPG\|thumb\|A railroad [[bogie]] and disc brakes]]

	Still-larger discs are used for [[railroad car]]s, [[tram]]s, and some [[airplane]]s. [[Passenger car (rail)\|Passenger rail cars]] and [[light rail vehicle]]s often use disc brakes outboard of the wheels, which helps ensure a free flow of cooling air. Some modern passenger rail cars, such as the [[Amfleet\|Amfleet II cars]], use inboard disc brakes. This reduces wear from debris and provides protection from rain and snow, which would make the discs slippery and unreliable. However, there is still plenty of cooling for reliable operation. Some airplanes have the brake mounted with very little cooling, and the brake gets hot when stopping. This is acceptable as there is sufficient time for cooling, where the maximum braking energy is very predictable. Should the braking energy exceed the maximum, for example during an emergency occurring during take-off, aircraft wheels can be fitted with a [[fusible plug]]<ref>{{cite web\|url= https://patents.google.com/patent/US4628953A/en \|title= Fusible plug safety device for venting aircraft tires}}</ref> to prevent the tire bursting. This is a milestone test in aircraft development.<ref>{{cite web\|url= https://www.airbus.com/newsroom/press-releases/en/2014/07/a350-xwb-msn001-successfully-conducted-maximum-energy-rejected-take-off-test.html \|title=A350 XWB MSN001 successfully conducted 'Maximum Energy Rejected Take-Off' test}}</ref>		Still-larger discs are used for [[railroad car]]s, [[tram]]s, and some [[airplane]]s. [[Passenger car (rail)\|Passenger rail cars]] and [[light rail vehicle]]s often use disc brakes outboard of the wheels, which helps ensure a free flow of cooling air. Some modern passenger rail cars, such as the [[Amfleet\|Amfleet II cars]], use inboard disc brakes. This reduces wear from debris and provides protection from rain and snow, which would make the discs slippery and unreliable. However, there is still plenty of cooling for reliable operation. Some airplanes have the brake mounted with very little cooling, and the brake gets hot when stopping. This is acceptable as there is sufficient time for cooling, where the maximum braking energy is very predictable. Should the braking energy exceed the maximum, for example during an emergency occurring during take-off, aircraft wheels can be fitted with a [[fusible plug]]<ref>{{cite web\|url= https://patents.google.com/patent/US4628953A/en \|title= Fusible plug safety device for venting aircraft tires}}</ref> to prevent the tire bursting. This is a milestone test in aircraft development.<ref>{{cite web\|url= https://www.airbus.com/newsroom/press-releases/en/2014/07/a350-xwb-msn001-successfully-conducted-maximum-energy-rejected-take-off-test.html \|title=A350 XWB MSN001 successfully conducted 'Maximum Energy Rejected Take-Off' test\|date=14 June 2021 }}</ref>

	=== Automotive use ===		=== Automotive use ===

← Previous revision		Revision as of 07:26, 13 August 2024
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	Disc brakes offer better stopping performance than drum brakes because the disc is more readily cooled. Consequently, discs are less prone to the [[brake fade]] caused when brake components overheat. Disc brakes also recover quicker from immersion (wet brakes are less effective than dry ones).<ref name="GiganticLeap"/>		Disc brakes offer better stopping performance than drum brakes because the disc is more readily cooled. Consequently, discs are less prone to the [[brake fade]] caused when brake components overheat. Disc brakes also recover quicker from immersion (wet brakes are less effective than dry ones).<ref name="GiganticLeap"/>

	Most drum brake designs have at least one leading shoe, which gives a [[Servomechanism\|servo-effect]]. By contrast, a disc brake has no self-servo effect, and its braking force is always proportional to the pressure placed on the brake pad by the braking system via any brake servo, brake pedal, or lever. This tends to give the driver a better "feel" and helps to avoid impending lockup. Drums are also prone to "bell mouthing" and trap worn lining material within the assembly, causing various braking problems.		Most drum brake designs have at least one leading shoe, which gives a [[Servomechanism\|servo-effect]]. By contrast, a disc brake has no self-servo effect, and its braking force is always proportional to the pressure placed on the brake pad by the braking system via any brake servo, brake pedal, or lever. This tends to give the driver a better "feel" and helps to avoid impending lockup. Drums are also prone to "bell mouthing" and trap worn lining material within the assembly, causing various braking problems.{{Cn\|date=August 2024}}

	The disc is usually made of [[cast iron]]. In some cases, it may be made of composites such as [[reinforced carbon–carbon]] or [[ceramic matrix composite]]s. This is connected to the ''wheel'' and the ''axle''. To slow down the wheel, friction material in the form of [[brake pad]]s, mounted on the [[brake caliper]], is forced mechanically, [[hydraulic brake\|hydraulically]], [[pneumatics\|pneumatically]], or [[electromagnet]]ically against both sides of the disc. [[Friction]] causes the disc and attached wheel to slow or stop.		The disc is usually made of [[cast iron]]. In some cases, it may be made of composites such as [[reinforced carbon–carbon]] or [[ceramic matrix composite]]s. This is connected to the ''wheel'' and the ''axle''. To slow down the wheel, friction material in the form of [[brake pad]]s, mounted on the [[brake caliper]], is forced mechanically, [[hydraulic brake\|hydraulically]], [[pneumatics\|pneumatically]], or [[electromagnet]]ically against both sides of the disc. [[Friction]] causes the disc and attached wheel to slow or stop.
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	The brake disc is the rotating part of a wheel's disc brake assembly, against which the brake pads are applied. The material is typically [[gray iron]],<ref name=Intro-Ihm/> a form of [[cast iron]]. The design of the discs varies. Some are solid, but others are hollowed out with fins or vanes joining the disc's two contact surfaces (usually included in the casting process). The weight and power of the vehicle determine the need for ventilated discs.<ref name="whatsnewAMC"/> The "ventilated" disc design helps to dissipate the generated heat and is commonly used on the more heavily loaded front discs.		The brake disc is the rotating part of a wheel's disc brake assembly, against which the brake pads are applied. The material is typically [[gray iron]],<ref name=Intro-Ihm/> a form of [[cast iron]]. The design of the discs varies. Some are solid, but others are hollowed out with fins or vanes joining the disc's two contact surfaces (usually included in the casting process). The weight and power of the vehicle determine the need for ventilated discs.<ref name="whatsnewAMC"/> The "ventilated" disc design helps to dissipate the generated heat and is commonly used on the more heavily loaded front discs.

	Discs for motorcycles, bicycles, and many cars often have holes or slots cut through the disc. This is done for better [[heat dissipation]], to aid surface-water dispersal, to reduce noise, to reduce mass, or for marketing cosmetics.		Discs for motorcycles, bicycles, and many cars often have holes or slots cut through the disc. This is done for better [[heat dissipation]], to aid surface-water dispersal, to reduce noise, to reduce mass, or for marketing cosmetics.{{Cn\|date=August 2024}}

	Slotted discs have shallow channels machined into the disc to aid in removing dust and gas. Slotting is preferred in most racing environments to remove gas and water and deglaze brake pads. Some discs are both drilled and slotted. Slotted discs are generally not used on standard vehicles because they quickly wear down brake pads; however, removing of material is beneficial to race vehicles since it keeps the pads soft and avoids [[Glass transition\|vitrification]] of their surfaces. On the road, drilled or slotted discs still have a positive effect in wet conditions because the holes or slots prevent a film of water from building up between the disc and the pads.		Slotted discs have shallow channels machined into the disc to aid in removing dust and gas. Slotting is preferred in most racing environments to remove gas and water and deglaze brake pads. Some discs are both drilled and slotted. Slotted discs are generally not used on standard vehicles because they quickly wear down brake pads; however, removing of material is beneficial to race vehicles since it keeps the pads soft and avoids [[Glass transition\|vitrification]] of their surfaces. On the road, drilled or slotted discs still have a positive effect in wet conditions because the holes or slots prevent a film of water from building up between the disc and the pads.

	Two-piece discs are when the center mounting part of the disc is manufactured separately from the outer friction ring. The central section used for fitment is often called the bell or hat because of its shape. It is commonly manufactured from an alloy such as a [[7075 aluminium alloy\|7075 alloy]] and hard [[anodised]] for a lasting finish. The outer disc ring is usually manufactured from [[Gray iron\|grey iron]]. They can also be from [[steel]] or [[Ceramic matrix composite\|carbon ceramic]] for particular applications. These materials originated from motorsport use and are available in high-performance vehicles and aftermarket upgrades. Two-piece discs can be supplied as a fixed assembly with regular nuts, bolts, and washers or a more complicated floating system where drive bobbins allow the two parts of the brake disc to expand and contract at different rates, therefore, reducing the chance a disc will warp from overheating. Key advantages of a two-piece disc are a saving in critical [[Un sprung weight\|un-sprung weight]] and the [[Dissipation factor\|dissipation]] of heat from the disc surface through the alloy bell (hat). Both fixed and floating options have their drawbacks and advantages. Floating discs are prone to rattle and collection of debris and are best suited to motorsport, whereas fixed are best for road use.<ref>{{cite web\|url= https://www.apracing.com/Info.aspx?InfoID=35&ProductID=1594 \|title=AP Racing - Race Car - Brake Discs - Ventilated Discs \|website=apracing.com \|access-date=2018-11-21}}</ref>		Two-piece discs are when the center mounting part of the disc is manufactured separately from the outer friction ring. The central section used for fitment is often called the bell or hat because of its shape. It is commonly manufactured from an alloy such as a [[7075 aluminium alloy\|7075 alloy]] and hard [[anodised]] for a lasting finish. The outer disc ring is usually manufactured from [[Gray iron\|grey iron]]. They can also be from [[steel]] or [[Ceramic matrix composite\|carbon ceramic]] for particular applications.{{Cn\|date=August 2024}} These materials originated from motorsport use and are available in high-performance vehicles and aftermarket upgrades. Two-piece discs can be supplied as a fixed assembly with regular nuts, bolts, and washers or a more complicated floating system where drive bobbins allow the two parts of the brake disc to expand and contract at different rates, therefore, reducing the chance a disc will warp from overheating. Key advantages of a two-piece disc are a saving in critical [[Un sprung weight\|un-sprung weight]] and the [[Dissipation factor\|dissipation]] of heat from the disc surface through the alloy bell (hat). Both fixed and floating options have their drawbacks and advantages. Floating discs are prone to rattle and collection of debris and are best suited to motorsport, whereas fixed are best for road use.<ref>{{cite web\|url= https://www.apracing.com/Info.aspx?InfoID=35&ProductID=1594 \|title=AP Racing - Race Car - Brake Discs - Ventilated Discs \|website=apracing.com \|access-date=2018-11-21}}</ref>

	==History==		==History==
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	Many early implementations for automobiles located the brakes on the [[inboard brake\|inboard]] side of the [[driveshaft]], near the [[differential (mechanics)\|differential]], while most brakes today are located inside the wheels. An inboard location reduces the [[unsprung weight]] and eliminates a source of heat transfer to the tires.		Many early implementations for automobiles located the brakes on the [[inboard brake\|inboard]] side of the [[driveshaft]], near the [[differential (mechanics)\|differential]], while most brakes today are located inside the wheels. An inboard location reduces the [[unsprung weight]] and eliminates a source of heat transfer to the tires.

	Historically, brake discs were manufactured worldwide with a concentration in Europe and America. Between 1989 and 2005, the manufacturing of brake discs migrated predominantly to China.		Historically, brake discs were manufactured worldwide with a concentration in Europe and America. Between 1989 and 2005, the manufacturing of brake discs migrated predominantly to China.{{Cn\|date=August 2024}}

	===In the U.S.===		===In the U.S.===