Radial piston motor

The radial piston motor is a mechanical drive that converts the pressure of an inflowing gas or liquid into rotary motion. It is particularly suitable for applications with high torques and low speeds. Originally from hydraulics, the radial piston principle has also been used in pneumatics for years.

In the radial piston engine, gas (pneumatics) or a liquid (hydraulic) flows centrally into the interior of the engine, where the pressure is transmitted to movable pistons that are arranged in a star-shaped manner. The pistons are provided with rollers and run on a curve built into the interior of the housing. Depending on the position of the pistons, compression and expansion alternate. Where the curve describes a valley, the pistons have more space and allow the medium to flow in; at the mountain, the piston is pushed back and the medium in it is compressed. This creates the rotation of the cylinder in which the radial pistons are incorporated. Only a minimum of compressed air is required.

Like the vane motor, the radial piston motor as a purely pneumatic drive is basically suitable for use in ATEX zones, i.e. in potentially explosive environments. Some models, such as the ATEX motors from PTM mechatronics, are already ATEX-certified ex works.

Compared to the vane motor, the radial piston motor is characterized by a significantly lower energy consumption – up to 90 percent savings potential – and a higher torque. It is therefore the much more efficient solution for applications with low speeds and high torque. The use of a transmission to achieve high torques is not necessary.


  • high energy efficiency: economical and powerful
  • high torque and high efficiency even without additional transmission
  • no starting torque required, full torque right from the start
  • resilient to a standstill
  • suitable for use in an ATEX environment (some are already ATEX-certified ex works)
  • suitable for use with water
  • suitable for use in clean rooms
  • suitable for applications with speeds of 30 to 300 revolutions per minute (without transmission) 
Leistungsstarke Druckluftmotoren, effizient mit hohem Wirkungsgrad und Drehmoment

Compressed air motors

We generate movement in special environments: ATEX-certified, stainless steel, clean room classified, IP68 waterproof, ferrite-free, acid / chemical-resistant and sterilizable with hydrogen peroxide.

Energie sparen Umwelt schützen


Our radial piston motors are the most efficient air motors – we prove this with facts and figures:

PTM Wiki

There is even more worth knowing in our PTM Wiki.

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