Ads
related to: helical rack and pinion gear and rail packages
Search results
Results from the WOW.Com Content Network
A rack and pinion has roughly the same purpose as a worm gear with a rack replacing the gear, in that both convert torque to linear force. However the rack and pinion generally provides higher linear speed — since a full turn of the pinion displaces the rack by an amount equal to the pinion's pitch circle whereas a full rotation of the worm screw only displaces the rack by one tooth width.
The trains are fitted with one or more cog wheels or pinions that mesh with this rack rail. This allows the trains to operate on steep gradients of 100% (45 degrees) or more, well above the 10% maximum for friction-based rail. The rack and pinion mechanism also provides more controlled braking and reduces the effects of snow or ice on the rails.
A crossed helical gear is a gear that operate on non-intersecting, non-parallel axes. The term crossed helical gears has superseded the term spiral gears. There is theoretically point contact between the teeth at any instant. They have teeth of the same or different helix angles, of the same or opposite hand.
A disadvantage of helical gears is a resultant thrust along the axis of the gear, which must be accommodated by appropriate thrust bearings. However, this issue can be circumvented by using a herringbone gear or double helical gear, which has no axial thrust - and also provides self-aligning of the gears. This results in less axial thrust than ...
Therefore, regardless of the worm's size (sensible engineering limits notwithstanding), the gear ratio is the "size of the worm wheel - to - 1". Given a single-start worm, a 20-tooth worm wheel reduces the speed by the ratio of 20:1. With spur gears, a gear of 12 teeth must match with a 240-tooth gear to achieve the same 20:1 ratio.
Carl Roman Abt (16 July 1850 – 1 May 1933 [1]) was a Swiss mechanical engineer, inventor and entrepreneur.He made groundbreaking innovations in rack-and-pinion railways, giving his name to one of the most widely used systems developed for mountain railways, the Abt rack system.
Ads
related to: helical rack and pinion gear and rail packages