Vane Air Motor Basics: Working Principle & Features

What is a vane air motor?

The vane air motor is a device that can convert the pressure of compressed air into rotational mechanical energy. The most widely used in pneumatic transmission are vane and piston types. It is mainly composed of motor housing, connecting rod, crankshaft, piston, cylinder, valve and so on. The compressed air enters the valve core to make it rotate, and at the same time, the compressed air is fed into the surrounding cylinders in turn by the rotation of the valve core. Due to the expansion of the compressed air in the cylinder, the piston rod and the crankshaft are pushed to rotate. When pushed to the "bottom dead center", the valve spool also moves to the first exhaust position.

How does a vane air motor work?

• The air enters the inlet chamber "a". Vane 2 has just sealed off the chamber "b" between itself and vane 3. The pressure in chamber "b" is still the inlet pressure. This pressure acts on vane 3, moving it in a clockwise direction.
  
• The vanes have rotated further and the expansion process in chamber "b" has started. The pressure in it is thereby reduced but there is still a net force moving the rotor forward as the area of vane 3 is larger than the area of vane 2 in chamber "b". Furthermore the inlet pressure acts on vane 2 in the inlet chamber "a".
• The vanes have moved further. Chamber "b" is now being emptied through the outlet and there is no more contribution from this chamber. The force moving the rotor forward now comes from the force on vane 1 and vane 2.
  

Due to this simple principle the energy of the compressed air is converted into rotational motion from chamber to chamber, and the motor turns.

What are the features of vane air motor?

Because the vane air motor has some prominent features, in some industrial occasions. It is more suitable than electric motors and hydraulic motors, these features are:

1. It has explosion-proof performance. Due to the characteristics of the working medium air of the air motor and the consideration of structural design, it can not generate sparks during work, so it is suitable for explosion, high temperature, dusty occasions, and can be used for extremely humid air environment without the risk of leakage.
2. The soft characteristics of the motor itself enable it to work at full load for a long time, with a small temperature rise and overload protection.
3. It has high starting torque and can start with load.
4. It is easy to press. The operation is simple, and it can realize stepless speed regulation.
5. Compared with the motor, the unit power size is small and the weight is light. It is suitable for installation in small places and hand tools.