The pinion is a spur gear, and mates with a toothed bar or rod that can be thought of as a spur gear with an infinitely large radius of curvature. Rack and pinion allows torque to be converted to linear force.

Sector gear is merely a segment of a spur gear, such as one half or one quarter of the circumference, but still attached to the axle in the normal fashion. The bending strength (РџС“) of gear tooth is given by These gears can be fitted only to parallel axles (Fig. These are Flat with teeth projecting radially in the plane of the wheel, 'straight-cut gears'. There is actually some loss of output power due to friction. Conservation of energy requires that the amount of power delivered by the output gear or shaft will never exceed the power applied to the input gear, regardless of the gear ratio. A gearbox is not an amplifier or a servomechanism. This is the principle of the automobile transmission, allowing selection between various mechanical advantages. The larger gear is known as a wheel and the smaller as a pinion. The teeth (or cogs) of a gear are shaped to minimize wear, vibration and noise, and to maximize the efficiency of power transmission.Р”Вifferent-sized gears are often used in pairs for a mechanical advantage, allowing the torque of the driving gear to produce a larger torque in the driven gear at lower speed, or a smaller torque at higher speed. To transmit power through right angle drive, because the crankshaft and rear axle are normally at right angles to each other.Р”Р„ gear is a toothed wheel designed to transmit torque to another gear or toothed component. To alter the ratio of wheel speed and engine speed in order to suit be field conditions. To make reduced speed available, to rear wheels of the tractor. To transmit power from the engine to the rear wheels of the tractor. Speed varies according to the field requirements and so a number of gear ratios are provided to suit the varying conditions. Today's four- and five-speed automatic transmissions need torque converters with coolant, radiators and hoses - all of which cause loss of power and efficiency.

Transmission's primary job is to allow engine to operate in four or five different speeds. The transmission uses gears to make more effective use of the engine and keeps the engine operating at an appropriate speed. This is done by suitable design of gear and shafts. So the gear box is fitted between engine and rear wheel for variable torque and speed. If the engine hp is constant, it is obvious that for higher torque at wheels, low speed is required and vice-versa. The purpose of transmission is to reduce the engine speed and increase the torque available at the rear wheels of the tractor because

Helical gear design procedure ppt