A universal joint

A universal joint, U joint, Cardan joint or Hardy-Spicer joint is a joint in a rigid rod that allows the rod to 'bend' in any direction. It consists of a pair of ordinary hinges located close together, but oriented at 90° relative to each other. Illustration of a universal joint created by Wapcaplet in Blender, composited in the GIMP. File links The following pages link to this file: Universal joint Categories: GFDL images ... Illustration of a universal joint created by Wapcaplet in Blender, composited in the GIMP. File links The following pages link to this file: Universal joint Categories: GFDL images ... Gerolamo Cardano or Jerome Cardan or Girolamo Cardan (September 24, 1501 - September 21, 1576) was a celebrated Italian Renaissance mathematician, physician, astrologer, and gambler. ... Clarence W. Spicer is known for inventing the Spicer joint, a type of Universal joint. ... A joint (articulation) is the location at which two bones make contact (articulate). ... A hinge is a mechanical device that connects two solid objects, allowing rotation between them. ...

Universal joints are common wherever a driveshaft needs to turn a corner; a driveshaft with a universal joint can freely rotate through the universal joint, and no gears are required to couple the two ends. The most obvious example of this application of a universal joint is in the driveshafts of automobiles, a technology known as the Hotchkiss drive. Cardan driveshaft with universal joints A driveshaft or driving shaft or Cardan shaft is a mechanical device for transferring power from the engine or motor to the point where useful work is applied. ... Karl Benzs Velo model (1894) - entered into the first automobile race An automobile is a wheeled passenger vehicle that carries its own motor. ... The dominant form of power transmission for front-engine, rear-drive cars in the twentieth century is called the Hotchkiss drive. ...

However, when the two shafts are at an angle other than 180°, the driven shaft does not rotate with the same speed as the drive shaft; the more the angle goes toward 90° the jerkier the movement gets (clearly, when the angle β = 90° the shafts would even lock).

The angular speed ω₂ of the driven shaft, as a function of the angular speed of the driving shaft ω₁ and the angle of the driving shaft φ₁, is found using: Angular frequency is a measure of how fast an object is rotating In physics (specifically mechanics and electrical engineering), angular frequency ω (also called angular speed) is a scalar measure of rotation rate. ...

and the angular acceleration, Angular acceleration is the rate of change of angular velocity over time. ...

Angular speed ω2 of driven shaft for different angles β

Download high resolution version (970x604, 46 KB)Universal joint, driven shaft angular speed ω2, graph of the function ω2 = ω1 · COS β/(1-SIN2 β · SIN2 φ1) for ω1 = 1, angle between shafts β = 15°, 30°, 45° and 60° and for one revolution (φ1 = 0. ... Download high resolution version (970x604, 46 KB)Universal joint, driven shaft angular speed ω2, graph of the function ω2 = ω1 · COS β/(1-SIN2 β · SIN2 φ1) for ω1 = 1, angle between shafts β = 15°, 30°, 45° and 60° and for one revolution (φ1 = 0. ...

Universal joints in a driveshaft

To prevent the jerky rotation of the axle or driven shaft there usually are two U-joints in a three part shaft assembly. The second U-joint will convert the jerky movement back to an even, uniform speed of the third shaft - if both the driving and the driven shaft are parallel.
Image File history File links Download high resolution version (1870x1555, 333 KB) Cardan_Shaft Picture made on my own File links The following pages link to this file: Universal joint Driveshaft ... Image File history File links Download high resolution version (1870x1555, 333 KB) Cardan_Shaft Picture made on my own File links The following pages link to this file: Universal joint Driveshaft ... Parallel is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. ...

CV joint

homokinetic joint

Another way to prevent jerky movement is to use a constant velocity (CV) or 'homokinetic' joint ('homo' meaning 'same', 'kinetic' meaning 'movement' or motion). A homokinetic joint has the same function as a U joint but is constructed with a cage and steel balls moving in grooves, inside a 'dome' (see picture). Homokinetic joint (CV joint) scan from a 1972 SAAB workshop manual This work is copyrighted. ... Homokinetic joint (CV joint) scan from a 1972 SAAB workshop manual This work is copyrighted. ... Cross-section through a typical outer CV joint (Saab 96) Constant Velocity Joints or homokinetic or CV joints allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. ... In physics, motion means a change in the position of a body with respect to time, as measured by a particular observer in a particular frame of reference. ...

1. driveshaft from the transmission,
2. steel balls (in this case 6) in a 'cage'. The balls run in grooves in the dome.
3. cage, splined to the driveshaft
4. spherical 'dome' and outer driveshaft, part of the hub of the wheel.

For a CV joint ω₂ = ω₁ for any angle β. In mechanics, a transmission or gearbox is the gear and/or hydraulic system that transmits mechanical power from a prime mover (which can be an engine or electric motor), to some form of useful output device. ... A spline consists of a long strip of wood (a lath, not to be confused with lathe) fixed in position at a number of points. ... A sphere (< Greek σφαίρα) is a perfectly symmetrical geometrical object. ...

History

The concept of the universal joint is based on the design of gimbals, which have been in use since antiquity. One anticipation of the universal joint was its use by the ancient greeks on ballistae. The first person known to have suggested its use for transmitting motive power was Gerolamo Cardano, an Italian mathematician, in 1545, although it is unclear whether he produced a working model. In Europe, the device is often called the Cardan joint or Cardan shaft. Robert Hooke produced a working universal joint in 1676, giving rise to an alternative name, the Hooke's joint. It was the American car manufacturer Henry Ford who gave it the name universal joint. A gimbal is a device using Euler angles to measure the rotation of an object in three dimensions and to control that rotation. ... The ballista (Latin, from Greek ballistēs, from ballein to throw, plural ballistae) was a powerful ancient weapon, similar to a giant crossbow, which ejected heavy darts or spherical stone projectiles of various sizes. ... Gerolamo Cardano or Jerome Cardan or Girolamo Cardan (September 24, 1501 - September 21, 1576) was a celebrated Italian Renaissance mathematician, physician, astrologer, and gambler. ... Events February 27 - Battle of Ancrum Moor - Scots victory over superior English forces December 13 - Official opening of the Council of Trent (closed 1563) Battle of Kawagoe - between two branches of Uesugi families and the late Hojo clan in Japan. ... A portrait, claimed by historian Lisa Jardine to be of Robert Hooke Robert Hooke, FRS (July 18, 1635 - March 3, 1703) was an English polymath who played an important role in the scientific revolution, through both experimental and theoretical work. ... Events January 29 - Feodor III becomes Tsar of Russia First measurement of the speed of light, by Ole Rømer Bacons Rebellion Russo-Turkish Wars commence. ... Further information: Ford Motor Company Time Magazine, January 14, 1935 Henry Ford (July 30, 1863 – April 7, 1947) was the founder of the Ford Motor Company. ...

See also

• gear coupling

A gear coupling is a mechanical device for transmitting torque between two shafts that are not coaxial. ...

References

• Theory of Machines 3 from National University of Ireland