Types of Gear

Gears are classified by the relative position between two meshing gears, relative velocity of meshing gears, profile of tooth of gears, position of meshing gears shaft and type of meshing. These all gears are classified as follow.



A. According to the position of shaft axes

1. Parallel shaft

a. Spur gears
b. Helical gears
c. Rack and pinion

2. Intersecting shaft

a. Straight bevel gears
b. Spiral bevel gears

3. Neither parallel nor intersecting shaft

a. Spiral gears
b. Worm and Worm wheel



B. According to velocity of the gears

1. Low velocity gears
2. Medium velocity gears
3. High velocity gears



C. According to type of meshing of gears

1. Externally meshing gears
2. Internally meshing gears

A. According to the position of shaft axes

In this category gears are classified by position of meshing gears shaft and relation between meshing gears shaft they are as follow.

1. Parallel shaft

In this type, meshing gear shafts are in parallel to each other and they are as follow.

a. Spur gears

Spur gears are a type of parallel shaft gears and known by their teeth. Gears are with teeth parallel to gear shaft are known as Spur Gears.

b. Helical gears

Helical gears have teeth at some angle with respect to gear shaft axis called as helix angle.

c. Rack and pinion

Rack is straight strip with teeth and pinion is a circular gear. Rack and pinions are used to convert rotary motion into reciprocating or reciprocating into rotary motion.

2. Intersecting shaft

The shafts of meshing gears are intersecting to each other are come in intersecting shaft gears.

a. Straight bevel gears

The straight gears teeth are form on a conical surface and parallel to gear axis are known as straight bevel gears.

b. Spiral bevel gears

The gears teeth forms on conical surface with at some angle with gear axis are known as spiral bevel gears.

3. Neither parallel nor intersecting shaft

Axes of this type of gears are neither parallel nor intersecting. These are as follow.

a. Spiral gears

Spiral gears also called as skew gears. Gears with high helix angle (angle between teeth gear and axis of gear) and use for transmitting power between two shafts which are neither parallel nor intersecting are called as spiral gears.

b. Worm and Worm wheel

Gears are use for transmitting power between shafts which are none intersecting to each other and their axes are in a right angle to each other, this type of gears are known as worm and worm wheel. Worm and worm wheel also use for reducing speed in large scale.

B. According to velocity of the gears

Gears are classified by relative velocity between two meshing gears are as follows.

1. Low velocity gears

Relative velocity between two meshing gears is said to be low at, velocity is less than 3 m/sec and known as low velocity gears.

2. Medium velocity gears

Relative velocity between two meshing gears is said to be medium at, velocity is between 3 to 15 m/sec and known as medium velocity gears.

3. High velocity gears

Relative velocity between two meshing gears is said to be high at, velocity is more than 15 m/sec and known as high velocity gears.

C. According to type of meshing of gears

Gears are classified as the contact between gears and position of gears is as follows.

1. Externally meshing gears

Gears which are mesh to each other externally are called as externally meshing gears.

2. Internally meshing gears

Gears which are mesh to each other internally are called as internally meshing gears.