# Types of Gears

There are many types of gears. Gear is generally defined as the rotating circular machine part which is having the teeth cut on its surface and these teeth mesh with the other teeth to transmit the torque and speed. Gear devices can generally change the torque, speed, and direction of a power source.

Two or more meshing gears that are working in a particular sequence are also called a gear train or a transmission. Gears are the main elements in the transmission system. The main thing is to know that if there is any misalignment or if the gear run out then it will result in chatter, noise, vibrations, and loss of power.

So now, first of all, we will check what are the advantages and disadvantages of gear drive.

• The gear drive transmits the exact velocity ratio
• It has high efficiency and reliable service
• It can be used to transmit the large power
• Moreover, it has a compact layout.

• The first main disadvantage is the manufacture of gears requires very special equipment and tools.
• Moreover, if there is an error in cutting teeth then it may cause noise and vibrations during the operation.

## Types of Gears

There are different types of gears. Gears can be classified as follows:

1. On the basis of the position of the axis of shafts
2. According to the peripheral velocity of the gear
3. According to the type of gear

let’s look at how we can classify the gears on the basis of the peripheral velocity of the gear. So according to the velocity of the gear, these are classified as low-velocity, medium-velocity, and high velocity. Let’s look at the difference between all these and how we classify them.

### 1. On the basis of the position of the axis of shafts

#### a.) Low-Velocity Gears

Low-velocity gears are defined as the gears having a velocity of less than 3 m/s.

#### b.) Medium-Velocity Gears

Medium-Velocity Gears are defined as the gas having a velocity between 3 to 15m/s.

#### c.) High-Velocity Gears

High-Velocity Gears are defined as gears which are having speed of more than 15m/s.

### 2. According to the Type of Gearing

There are different types of gears, according to the type of gearing, the gears may be classified as

• External gearing
• Internal gearing
• Rack and pinion.

Now, we will discuss each one by one.

#### a.) External Gearing

External Gearing is defined as the gears when the gears of two shafts mesh with each other externally. Out of these two gears, the bigger one is called the spur wheel, and the smaller one is called the pinion. The motion of both the gears will be different i.e if one will rotate in a clockwise direction, then the other will be rotating in an anticlockwise direction.

#### b.) Internal Gearing

Internal gearing is defined as when the gears of two shafts mesh with each other internally. Out of these two gears, the bigger one is called the annular wheel, and the smaller one is called the pinion. The motion in the internal bearing will always be in the same direction i.e if one is rotating in the clockwise the other will also rotate in the clockwise direction.

#### c.) Rack and Pinion

Rack and pinion are defined as when the gear of a shaft meshes with the others internally or externally in a straight line, such types of gear are called rack and pinion. Out of these both gears, the straight one is called the rank and the circular wheel is called the pinion. With the help of this gearing, we can convert rotary motion into linear motion and vice-versa.

### 3. On the basis of the position of the axis of shafts

There are different types of gears according to position of axis of shafts. We can divide the gears on the basis of the position of the axis of the shaft in the following ways:

• Parallel
• Intersecting
• Non-intersecting and non-parallel.

We will discuss each of them one by one:

#### a.) Parallel Gears

##### i.) Spur Gears

In the parallel gears, the teeth of the gears are parallel to the axis of the shaft. This arrangement is also spur gearing. Due to this arrangement, there is a radial reaction load on the shaft but not the axial loads. Spur gears are excellent when running at medium speed but it tends to be noisy at higher speed.

##### ii.) Helical Gears

Helical gears are those gears, which have teeth oriented at an angle to the axis of the shaft. This is just opposite to the spur gear, in which teeth are parallel to the axis of the shaft. This arrangement can carry more load as there is more than one tooth in contact during operation. Helical gear is smoother in operation and does not produce as much noise as spur gears. A disadvantage is that it produces thrust load while operating and it needs to be considered when the helical gears are used.

##### iii. ) Double Helical Gears

Double helical gears are kind of helical gears in which two helical faces are placed next to each other. The biggest advantage is that it eliminated the thrust load and provides a smoother operation than helical gears.

#### b.) Non-Parallel or Intersecting

##### i.) Bevel Gears

Bevel gears are used to transmit the power, where the shaft intersects at an angle. This arrangement is also called bevel gearing. These bevel gears are more costly and do not produce much torque. When in bevel gearing, two shafts intersect at an angle of 90 degrees, it is called miter gear.

#### c.) Non-intersecting and non-parallel

##### i.) Worm Gear

A worm gear is when a screw-type shape is there on the shaft and the mating gear is known as a worm wheel and transmits power through right angles on non-intersecting. These gear are good at high shock load applications but it has very low efficiency as compared to other gears. These gears produce thurst loads.

##### ii.) Hypoid Gear

Hypoid Gears are like spiral gears but they operate on shafts that do not intersect. These are almost always designed to operate at a 90-degree angle.

You might have understood different types of gears. If you have any questions, kindly comment down below.