What are Pneumatic Motors? Types of pneumatic motors

Technical Studies – Study 23


Pneumatic motor is a rotary actuator that converts pneumatic energy into mechanical rotary motion. Pneumatic motors are widely used due to their advantages.


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Advantages of pneumatic motors are –

  • Torque and speed of pneumatic motors can be adjusted easily.
  • Pneumatic motors are safe to operate in explosive environments.
  • It is overload safe.

Types of pneumatic motors:

According to the design and applications, the pneumatic motors are categorized into five types –

  • Piston Motor
  • Gear Motor
  • Vane Motor
  • Turbo Motor
  • Roots Motor

Piston Motor:

Piston motor is designed using several pistons for trouble free operation. piston motors are of two types –

  • Axial piston motor
  • Radial piston motor

Axial piston motor:

Axial piston motor has five or more pistons arranged axially and connected to a swash plate. The swash plate is connected to the motor shaft by bevel gears. When compressed air is applied to the motor the pistons get activate and impact a rotary motion to the swash plate. The swash plate transmits the rotary motion to the motor shaft by the bevel gears.

These motors can operate in both clockwise and anti-clockwise direction.

Axial piston motor
Radial piston motor:

Generally, in radial piston motor five or six pistons are organized radially. These piston rods are connected to the motor shaft. The motor shaft rotates due to the force from the piston rods.

These motors can produce high power at low speed. The power of this motor is affected by number of pistons used, piston speed, piston area and input pressure.

Radial piston motor

Gear motor:

Gear motors are designed for high power applications up to 45 KW. These motors have two connected gears, one inlet port and one outlet port. The torque of this motor depends on the pressure of the air applied to the tooth of the gears.

When compressed air is applied to the inlet of this motor, it influences the tooth of the gears and forces them to rotate and exhausts through the outlet port. By using helical gears the efficiency of this motor can be increased.

Pneumatic motor
Gear motor

Vane motor:

The construction of vane motor is similar to the sliding vane rotary compressor. The shaft of this motor is eccentric in design. This creates chambers in half part of the motor.

When compressed air is applied to this motor the chambers get filled and force the vanes to move. Due to pressure the vanes start moving and make the motor shaft to rotate.

Vane motors are widely used in manufacturing industries. Because of low weight and simple design vane motors are used in hand tools. Almost all pneumatic tools used in manufacturing industries use vane motors.   

Pneumatic motor
Vane motor


Turbo motor:

Turbo motor produces very low torque compared to other pneumatic motors. These motors are capable of producing high speed up to 100000 rpm. Turbo motors are used in very high speed applications, such as small tool grinders, dental drills etc.

Pneumatic motor
Turbo motor

Roots motor:

These motors are same as gear motor. In this motor instead of gears two roots are connected. Below there is a diagram of roots motor.   

Pneumatic motor
Roots motor


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