The design and working principle of the vane air motor
Vane air motors are produced with power ratings up to approximately 5 kW. It has a basic design and consists of only a few components.
Design
A slotted rotor rotates eccentrically in the chamber formed by the cylinder and cylinder end plates. Because the rotor is off-center and its diameter smaller than that of the cylinder, it creates a crescent-shaped chamber. The rotor slots contain air motor vanes that move freely, dividing the chamber into separate working sections of varying sizes. The combination of centrifugal force and the pressure of compressed air pushes the air motor vanes against the cylinder wall to seal each chamber. The effectiveness of this sealing process directly impacts air motor efficiency, as it depends on minimizing internal leakage.
1. Front end plate
2. Rotor
3. Vane
4. Cylinder
5. Rear end plate
Working principle
Working principle of an air motor
A. The air enters the inlet chamber “a.” Vane 2 has just sealed off 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.
B. The vanes have rotated further and the expansion process in chamber “b” has started. The pressure in the chamber is reduced, but there is still a net force moving the rotor forward as vane 3 has a larger area than vane 2 in chamber “b.” Additionally, the inlet pressure applies force to vane 2 within the inlet chamber "a."
C. 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.
Thanks to this principle, the energy of the compressed air is converted into rotational motion as it moves from one chamber to another, causing the motor to turn.
Thanks to this principle, the energy of the compressed air is converted into rotational motion as it moves from one chamber to another, causing the motor to turn.