Gas motor (pneumatic motor) is also a kind of pneumatic actuating element. Its function is equivalent to a motor or a hydraulic motor, that is, the output torque, and the drag mechanism is rotating.

1. Classification and characteristics of gas motor

The air motor can be divided into blade type gas motor, piston type gas motor and gear type gas motor according to the structure form. The most common are the piston type gas motor and the blade type gas motor. Vane gas motor is simple and compact, but it has low speed torque and low speed performance. It is suitable for medium and low power machinery. It is widely used in mines and pneumatic tools. Piston type air motor has a larger output power at low speeds, the low-speed performance is good, suitable for large loads and low-speed torque of the machine, such as crane, winch, winch, machine etc..

Compared with the hydraulic motor, the gas motor has the following characteristics:

(1) work safety. It can work in flammable and explosive places and is not affected by high temperature and vibration.

(2) it can be fully loaded for a long time while the temperature rise is smaller.

(3) it can be stepless speed regulation. The control of the intake flow can adjust the speed and power of the motor. The rated speed is transferred to hundreds of thousands of parts per minute.

(4) high starting torque. It can be carried directly with the load.

(5) simple structure, convenient operation, easy maintenance and low cost;

(6) the output power is relatively small, and the maximum is only about 20kW.

(7) large amount of air consumption, low efficiency and great noise.

2. The working principle of the gas motor

Figure 4 (a) is the working principle of a blade type gas motor. The main structure and working principle of hydraulic vane motor which is similar, mainly includes a radial with 3 ~ 10 bladed rotor, eccentrically mounted on the stator and rotor on both sides of the front cover (not shown in the figure), leaves in the groove of the rotor radial sliding blade through the bottom of the compressed air, rotor the rotation is by centrifugal force and the bottom of the blade pressure blade pressed on the inner surface of the stator. The stator has a semicircular trench that provides compressed air and exhaust gas.

When the compressed air enters the stator from the A port, the blade will drive the rotor to rotate counterclockwise and produce the torque. The exhaust gas is discharged from the exhaust port C, while the residual gas in the stator cavity is discharged from the B port. If you need to change the direction of the rotation of the gas motor, just change the inlet and exhaust port.