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brake (n.)
1.foot pedal that moves a piston in the master brake cylinder
2.a restraint used to slow or stop a vehicle
3.an area thickly overgrown usually with one kind of plant
4.large coarse fern often several feet high; essentially weed ferns; cosmopolitan
5.any of various ferns of the genus Pteris having pinnately compound leaves and including several popular houseplants
6.anything that slows or hinders a process"she wan not ready to put the brakes on her life with a marriage" "new legislation will put the brakes on spending"
brake (v. intr.)
1.cause to stop by applying the brakes"brake the car before you go into a curve"
2.stop travelling by applying a brake"We had to brake suddenly when a chicken crossed the road"
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Merriam Webster
BrakeBrake (brāk), imp. of Break. [Arhaic] Tennyson.
BrakeBrake, n. [OE. brake fern; cf. AS. bracce fern, LG. brake willow bush, Da. bregne fern, G. brach fallow; prob. orig. the growth on rough, broken ground, fr. the root of E. break. See Break, v. t., cf. Bracken, and 2d Brake, n.]
1. (Bot.) A fern of the genus Pteris, esp. the Pteris aquilina, common in almost all countries. It has solitary stems dividing into three principal branches. Less properly: Any fern.
2. A thicket; a place overgrown with shrubs and brambles, with undergrowth and ferns, or with canes.
Rounds rising hillocks, brakes obscure and rough,
To shelter thee from tempest and from rain. Shak.
He stayed not for brake, and he stopped not for stone. Sir W. Scott.
Cane brake, a thicket of canes. See Canebrake.
BrakeBrake (brāk), n. [OE. brake; cf. LG. brake an instrument for breaking flax, G. breche, fr. the root of E. break. See Break, v. t., and cf. Breach.]
1. An instrument or machine to break or bruise the woody part of flax or hemp so that it may be separated from the fiber.
2. An extended handle by means of which a number of men can unite in working a pump, as in a fire engine.
3. A baker's kneading though. Johnson.
4. A sharp bit or snaffle.
Pampered jades . . . which need nor break nor bit. Gascoigne.
5. A frame for confining a refractory horse while the smith is shoeing him; also, an inclosure to restrain cattle, horses, etc.
A horse . . . which Philip had bought . . . and because of his fierceness kept him within a brake of iron bars. J. Brende.
6. That part of a carriage, as of a movable battery, or engine, which enables it to turn.
7. (Mil.) An ancient engine of war analogous to the crossbow and ballista.
8. (Agric.) A large, heavy harrow for breaking clods after plowing; a drag.
9. A piece of mechanism for retarding or stopping motion by friction, as of a carriage or railway car, by the pressure of rubbers against the wheels, or of clogs or ratchets against the track or roadway, or of a pivoted lever against a wheel or drum in a machine.
10. (Engin.) An apparatus for testing the power of a steam engine, or other motor, by weighing the amount of friction that the motor will overcome; a friction brake.
11. A cart or carriage without a body, used in breaking in horses.
12. An ancient instrument of torture. Holinshed.
Air brake. See Air brake, in the Vocabulary. -- Brake beam or Brake bar, the beam that connects the brake blocks of opposite wheels. -- Brake block. (a) The part of a brake holding the brake shoe. (b) A brake shoe. -- Brake shoe or Brake rubber, the part of a brake against which the wheel rubs. -- Brake wheel, a wheel on the platform or top of a car by which brakes are operated. -- Continuous brake . See under Continuous.
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⇨ definición de brake (Wikipedia)
brake (n.)
bracken, brake pedal, curb, pasture brake, Pteridium aquilinum
brake (v.)
Ver también
⇨ American rock brake • air brake • brake assistance system • brake band • brake cylinder • brake disc • brake disk • brake drum • brake failure • brake light • brake lining • brake man • brake pad • brake pedal • brake pie clamp • brake pipe anchor • brake pipe clamp • brake rotor • brake shoe • brake system • hand brake • purple rock brake • rock brake
⇨ Advanced Brake Warning • Air brake • Air brake (aircraft) • Air brake (commercial vehicle) • Air brake (road vehicle) • All Gas. No Brake. • Anti-lock Brake Controller • Audi Shooting Brake • Band brake • Bicycle brake • Bicycle brake systems • Bike brake • Blended brake • Boom brake • Brake (Unterweser) station • Brake (carriage) • Brake (charity) • Brake (disambiguation) • Brake (sheet metal bending) • Brake (surname) • Brake Assist • Brake Bros Ltd • Brake Gangwayed • Brake My Wife, Please • Brake Post Office Stowage Van • Brake Standard Open • Brake Standard Open (Micro-Buffet) • Brake bleeding • Brake fade • Brake fluid • Brake force • Brake house • Brake lining • Brake on a wheel • Brake on the wheel • Brake pad • Brake run • Brake shoe • Brake shoes • Brake specific fuel consumption • Brake test • Brake to Vacate • Brake van • Brake's Cove, Newfoundland and Labrador • Brake, Lower Saxony • Brake, West Virginia • Brake-by-wire • Break-brake distinction • Break-brake merger • Brian Brake • Cable-actuated brake • Colin Brake • Collision Warning Brake Support • Cornering Brake Control • Counter-pressure brake • Countersteam brake • De Prony brake • Dead man's brake • Dead-man's brake • Disc brake • Disk brake • Driver's brake valve • Driving Brake Standard Open • Drum brake • E-brake • Eddy current brake • Electro-pneumatic brake system on British railway trains • Electromagnetic brake • Electronic brake force distribution • Electronically Controlled Brake • Emergency Brake Assist • Emergency Brake Light • Emergency brake • Emergency brake (train) • Energy Regeneration Brake • Exhaust brake • Handy Brake National Wildlife Refuge • Hayes Brake • Heberlein brake • Hydraulic brake • Inboard brake • Jack Brake • Jake brake • John Brake • Knorr brake • Kunze-Knorr brake • Leading/trailing drum brake • Lippe-Brake • Mark Brake • Mathews Brake National Wildlife Refuge • Maximum brake torque • Monro Muffler and Brake • Morgan Brake National Wildlife Refuge • Muzzle brake • New York Air Brake • Overrun brake • Parking brake • Patricia Brake • Power brake • Press brake • Railway air brake • Railway brake • Regenerative brake • Richard Brake • Rod-actuated brake • Rotor (brake) • Sensotronic Brake Control • Shear/press-brake • Shooting-brake • Solenoid brake • Steam brake • The Raymond Brake • Third brake light • Tom Brake • Track brake • Trailer brake controller • Twin leading drum brake • Vacuum brake • Vehicle brake • Water brake • Watson Brake • Westinghouse Air Brake Company • Westinghouse Brake and Signal Company Ltd
brake (n.)
pedal; treadle; foot pedal; foot lever[Classe]
poste de conduite d'une auto (fr)[DomainDescrip.]
brake (n.)
brake[ClasseHyper.]
voiture à cheval (fr)[DomainDescrip.]
poste de conduite d'une auto (fr)[DomainDescrip.]
véhicule à deux roues (dans le même axe) (fr)[DomainDescrip.]
brake (n.)
ensemble d'arbres (fr)[Classe]
(thickness)[Caract.]
brake (n.)
brake (n.)
bracken, fern[Hyper.]
genus Pteris, Pteris[membre]
brake (n.)
constraint, restraint[Hyper.]
brake (v. intr.)
faire réduire la vitesse (fr)[Classe]
(brake)[termes liés]
brake (v. intr.)
Wikipedia
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2010) |
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes.
Most commonly brakes use friction to convert kinetic energy into heat, though other methods of energy conversion may be employed. For example regenerative braking converts much of the energy to electrical energy, which may be stored for later use. Other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert kinetic energy into electric current in the brake disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic energy into different forms, for example by transferring the energy to a rotating flywheel.
Brakes are generally applied to rotating axles or wheels, but may also take other forms such as the surface of a moving fluid (flaps deployed into water or air). Some vehicles use a combination of braking mechanisms, such as drag racing cars with both wheel brakes and a parachute, or airplanes with both wheel brakes and drag flaps raised into the air during landing.
Since kinetic energy increases quadratically with velocity (), an object moving at 10 m/s has 100 times as much energy as one of the same mass moving at 1 m/s, and consequently the theoretical braking distance, when braking at the traction limit, is 100 times as long. In practice, fast vehicles usually have significant air drag, and energy lost to air drag rises quickly with speed.
Almost all wheeled vehicles have a brake of some sort. Even baggage carts and shopping carts may have them for use on a moving ramp. Most fixed-wing aircraft are fitted with wheel brakes on the undercarriage. Some aircraft also feature air brakes designed to reduce their speed in flight. Notable examples include gliders and some World War II-era aircraft, primarily some fighter aircraft and many dive bombers of the era. These allow the aircraft to maintain a safe speed in a steep descent. The Saab B 17 dive bomber used the deployed undercarriage as an air brake.
Friction brakes on automobiles store braking heat in the drum brake or disc brake while braking then conduct it to the air gradually. When traveling downhill some vehicles can use their engines to brake.
When the brake pedal of a modern vehicle with hydraulic brakes is pushed, ultimately a piston pushes the brake pad against the brake disc which slows the wheel down. On the brake drum it is similar as the cylinder pushes the brake shoes against the drum which also slows the wheel down.
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Brakes may be broadly described as using friction, pumping, or electromagnetics. One brake may use several principles: for example, a pump may pass fluid through an orifice to create friction:
Brakes are often described according to several characteristics including:
Most modern vehicles use a vacuum assisted brake system that greatly increases the force applied to the vehicle's brakes by its operator.[1] This additional force is supplied by the manifold vacuum generated by air flow being obstructed by the throttle on a running engine. This force is greatly reduced when the engine is running at fully open throttle, as the difference between ambient air pressure and manifold (absolute) air pressure is reduced, and therefore available vacuum is diminished. However, brakes are rarely applied at full throttle; the driver takes the right foot off the gas pedal and moves it to the brake pedal - unless left-foot braking is used.
Because of low vacuum at high RPM, reports of unintended acceleration are often accompanied by complaints of failed or weakened brakes, as the high-revving engine, having an open throttle, is unable to provide enough vacuum to power the brake booster. This problem is exacerbated in vehicles equipped with automatic transmissions as the vehicle will automatically downshift upon application of the brakes, thereby increasing the torque delivered to the driven-wheels in contact with the road surface.
Although ideally a brake would convert all the kinetic energy into heat, in practice a significant amount may be converted into acoustic energy instead, contributing to noise pollution.
For road vehicles, the noise produced varies significantly with tire construction, road surface, and the magnitude of the deceleration.[2] Noise can be caused by different things. These are signs that there may be issues with brakes wearing out over time.
A significant amount of energy is always lost while braking, even with regenerative braking which is not perfectly efficient. Therefore a good metric of efficient energy use while driving is to note how much one is braking. If the majority of deceleration is from unavoidable friction instead of braking, one is squeezing out most of the service from the vehicle. Minimizing brake use is one of the fuel economy-maximizing behaviors.
While energy is always lost during a brake event, a secondary factor that influences efficiency is "off-brake drag", or drag that occurs when the brake is not intentionally actuated. After a braking event, hydraulic pressure drops in the system, allowing the brake caliper pistons to retract. However, this retraction must accommodate all compliance in the system (under pressure) as well as thermal distortion of components like the brake disc or the brake system will drag until the contact with the disc, for example, knocks the pads and pistons back from the rubbing surface. During this time, there can be significant brake drag. This brake drag can lead to significant parasitic power loss, thus impact fuel economy and vehicle performance.
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