Manufacturing Processes-2

Muhammad Sajjad BSME-01113138+923337179484

Rack and Pinion

Rack and Pinion

GearsA gear is a component

within a transmission device that transmits rotational force to another gear or device. A gear is different from a pulley in that a gear is a round wheel that has linkages ("teeth" or "cogs") that mesh with other gear teeth, allowing force to be fully transferred without slippage.

A rack and pinion gear system composed of two gears. The normal round gear is called “pinion” gear and straight or flat gear is called “Rack” gear.

Rack and Pinion

Rack and PinionA rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. The circular pinion engages teeth on a linear "gear" bar which is called the “rack“.

Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel. For example, in a rack railway, the rotation of a pinion mounted on a locomotive or a railcar engages a rack between the rails and pulls a train along a steep slope.

The rack and pinion is also used to convert between rotary and linear motion. The rack is the flat, toothed part, and the pinion is the gear. Rack and pinion can convert from rotary to linear of from linear to rotary motion.

Rack-and-pinion SteeringRack and Pinions are commonly used in the steering system of cars to convert the rotary motion of the steering wheel to the side to side motion in the wheels.The steering ratio is defined by the ratio of pinion revolutions(steering wheelrevolutions) to rack travel. Suitable toothing of the rack allows the ratio to be made variable over the travel. This lowers the actuating force or reduces the travel for steering corrections.

Rack and pinion steering is quickly becoming the most common type of steering on cars, small trucks. It is actually a pretty simple mechanism. A rack-and-pinion gear set is enclosed in a metal tube, with each end of the rack sticking out from the tube. A rod, called a tie rod, connects to each end of the rack.

The pinion gear is attached to the steering shaft. When you turn the steering wheel, the gear spins, moving the rack.

The rack-and-pinion gear set does two

things:It converts the rotational motion of the

steering wheel into the linear motion needed to turn the wheels.

It provides a gear reduction, making it easier to turn the wheels.

On most cars, it takes three to four complete revolutions of the steering wheel to make the wheels turn from lock to lock (from far left to far right).

The primary components of the rack and pinion steering system are:

Rubber bellowsPinionRackInner ball joint or socketTie-rod

ChainA chain is a series of connected links which are typically

made of metal. A chain may consist of two or more links.Chains are usually made in one of two styles, according

to their intended use:Those designed for lifting, such as when used with a 

hoist; for pulling; or for securing, such as with a bicycle lock, have links that are torus shaped, which make the chain flexible in two dimensions (The fixed third dimension being a chain's length.)

Those designed for transferring power in machines have links designed to mesh with the teeth of the sprockets of the machine, and are flexible in only one dimension. They are known as roller chains, though there are also non-roller chains such as block chain.