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Hydraulic brake

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The hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing ethylene glycol, to transfer pressure from the controlling mechanism to the braking mechanism

History

Fred Duesenberg originated hydraulic brakes on his 1914 racing cars and Duesenberg was the first automotive marque to use the technology on a passenger car in 1921. This braking system could have earned him a fortune if he had patented it. In 1918 Malcolm Lougheed (who later changed the spelling of his name to Lockheed) developed a hydraulic brake system.[1]

Construction

The most common arrangement of hydraulic brakes for passenger vehicles, motorcycles, scooters, and mopeds, consists of the following:

  • Brake pedal or lever
  • A pushrod (also called an actuating rod)
  • A master cylinder assembly containing a piston assembly (made up of either one or two pistons, a return spring, a series of gaskets/ O-rings and a fluid reservoir)
  • Reinforced hydraulic lines
  • Brake caliper assembly usually consisting of one or two hollow aluminum or chrome-plated steel pistons (called caliper pistons), a set of thermally conductive brake pads and a rotor (also called a brake disc) or drum attached to an axle.

The system is usually filled with a glycol-ether based brake fluid (other fluids may also be used).

At one time, passenger vehicles commonly employed drum brakes on all four wheels. Later, disc brakes were used for the front and drum brakes for the rear. However disc brakes have shown better heat dissipation and greater resistance to 'fading' and are therefore generally safer than drum brakes. So four-wheel disc brakes have become increasingly popular, replacing drums on all but the most basic vehicles. Many two-wheel vehicle designs, however, continue to employ a drum brake for the rear wheel.

The following description uses the terminology for and configuration of a simple disc brake.

System operation

The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%.[2] Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm3.[3] Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average.[4] According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transit

See also

References

  1. ^ Csere, Csaba (January 1988), "10 Best Engineering Breakthroughs", Car and Driver, vol. 33, no. 7, p. 61

Patents

  • US 2746575  Disc brakes for road and other vehicles. Kinchin 1956-05-22
  • US 2591793  Device for adjusting the return travel of fluid actuated means. Dubois 1952-04-08
  • US 2544849  Hydraulic brake automatic adjuster. Martin 1951-03-13
  • US 2485032  Brake apparatus. Bryant 1949-10-08
  • US 2466990  Single disk brake. Johnson Wade C, Trishman Harry A, Stratton Edgar H. 1949-04-12
  • US 2416091  Fluid pressure control mechanism. Fitch 1947-02-12
  • US 2405219  Disk brake. Lambert Homer T. 1946-08-06
  • US 2375855  Multiple disk brake. Lambert Homer T. 1945-05-15
  • US 2366093  Brake. Forbes Joseph A. 1944-12-26
  • US 2140752  Brake. La Brie 1938-12-20
  • US 2084216  V-type brake for motor vehicles. Poage Robert A. and Poage Marlin Z. 1937-06-15
  • US 2028488  Brake. Avery William Leicester 1936-02-21
  • US 1959049  Friction Brake. Buus Niels Peter Valdemar 1934-05-15
  • US 1954534  Brake. Norton Raymond J 1934-04-10
  • US 1721370  Brake for use on vehicles. Boughton Edward Bishop 1929-07-16
  • DE 695921  Antriebsvorrichtung mit hydraulischem Gestaenge.... Borgwar Carl Friedrich Wilhelm 1940-09-06
  • GB 377478  Improvements in wheel cylinders for hydraulic brakes. Hall Frederick Harold 1932-07-28
  • GB 365069  Improvements in control gear for hydraulically operated devices and particularly brakes for vehicles. Rubury John Meredith 1932-01-06
  • Erjavec, Jack (2004). Automotive Technology: A Systems Approach, Delmar Cengage Learning. ISBN 1-4018-4831-1
  • Allan and Malcolm Loughead (Lockheed) Their Early Lives in the Santa Cruz Mountains including the invention of the hydraulic brake.


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