Hydraulic motors

A hydraulic motor turns flow into rotation. Two figures define it: displacement, which sets the torque at a given pressure, and the flow available, which sets the speed. The rest comes down to the mechanical strength of the shaft and its bearing.

The orbital motor, with internal gear teeth, gives high torque at low to medium speed in a compact package: it is the most common choice on conveyors, augers and auxiliary drives. The gear motor runs fast at moderate torque. The piston motor is about efficiency and transmitted power, particularly in hydrostatic transmissions. Low-speed high-torque motors do away with the mechanical reduction gearbox.

• Always check the permissible radial and axial load on the shaft before fitting a pulley or a sprocket.
• The drain line goes straight back to the tank, with no back pressure: a badly connected drain wrecks the shaft seals.
• A spring-applied multi-disc brake holds the load once the motor has stopped; it does not replace a service brake.

We work out the motor from the function it has to drive, and supply the brake, counterbalance valve and valving that go with it.