Connecting Methods of Bevel Gears, Straight bevel gears, hypoid gears, spiral bevel gears, worm and worm wheel gear – Automobile studymaterial


Connecting methods of bevel gears

Based on the arrangement of the
teeth in the pinion gear, the connecting methods with crown wheel are classified in to four different types.

1. Straight bevel gears
2. Spiral bevel gears
3. Hypoid gears
4. Worm and worm wheel

Straight bevel gears

In this type the gear teeth are cut in straight and connected at the center of the pinion. To operate this more amount of energy is required. In addition, when it is in operation, it produces more noise and it wears quickly.

Spiral bevel gears

In this type of gears the teeth are cut
in the inclined position. Hence the teeth are very well in mesh with the other teeth and the energy is transferred very softly and uniformly. In this type the axis of the crown wheel and the pinion are arranged
in the same axis. This gear works without any noise and lasts for a long time.


1. It has a strong arrangement.
2. It is more efficient.
3. Silent and smooth in operation.


1. Arranging the parts is very difficult.
2. It is more expensive.

Hypoid gears

In this type of gears the teeth are
cut in spiral shape. In this arrangement the pinion gear is placed just below the center of the crown gear and hence the height of the chassis is reduced.

This type is mostly used in heavy
vehicles. During its operation more heat is generated in it. Hence for reducing the heat generated, more amount of lubricating oil is required. It functions smoothly and works for long time.


1. Safe to operate and it is less noisy in
2. The height of chassis is less.
3. It can withstand maximum amount of rotational torque.


1. It has low ground clearance.
2. Assembling and dismantling the parts is difficult. Repairing the parts is difficult.

3. It requires lubricating oil which must withstand high pressure.


1. It is used mostly in the vehicles which are used for aged persons and patients.
2. It is used mostly in foreign cars.

Worm and worm wheel

In this type of gear in worm and
worm wheel are used instead of pinion and crown wheel. The worm in this arrangement is located
as per the design either above or below the Worm Wheel. It is used mainly in heavy vehicles. It gives a smooth, superior and stable motion of operation. Worm is made of nickel and stabilized steel. Worm wheel is made up off phosphorous bronze material.


1. Reduces the speed very quickly.
2. Transmission power is high.
3. Noiseless in operation.
4. By placing the worm at the upper side the ground clearance is increased.


1. Assembling and repairing of parts is difficult.
2. It needs special lubricating oil.
3. It has very less ground clearance.
4. High cost and heavy weight.
5. It is suitable only for heavy vehicles.

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