Radial piston motors – find manufacturers and suppliers

Radial piston motors are hydraulic drives that are driven by the pressure of hydraulic fluid and generate mechanical energy in the form of a rotary movement.

In contrast to other hydraulic motors (e.g. axial piston or gear motors), radial piston motors are characterized by high torque at low speeds.

Below you will find the function and design of radial piston motors, an overview of types, their areas of application and their advantages:

How radial piston motors work:

Radial piston motors can operate with a constant or variable delivery volume, enabling infinitely variable speed control.

1. Hydraulic oil is fed into the motor under pressure.
2. The pressure of the hydraulic oil moves the radially arranged pistons outwards (cam ring) or inwards (crankshaft), depending on the design.
3. The pistons press against a cam ring or a crankshaft, creating a rotary movement.
4. The used oil is drained via the return line and the process is repeated.

Design of radial piston engines:

Typical radial piston engines consist of the following main components:

1. The housing contains all moving parts and carries the hydraulic oil.
2. The pistons are arranged radially around a central axis and are moved by the hydraulic pressure.
3. The cylinder block contains the pistons and the lines for the hydraulic oil.
4. The cam ring or crankshaft converts the piston movement into a rotary movement.
5. The hydraulic connections regulate the oil flow for forward and reverse movement.

Types of radial piston engines:

There are different designs that are suitable for different applications:

1. Internal rotor radial piston motor:
   Pistons push against a central crankshaft.
   These types generate high torques with a compact design.
   Use: Mobile applications (e.g. construction machinery).
2. External rotor radial piston motor:
   Pistons press against an external cam ring.
   This design has a very high efficiency and high power density.
   Application: Stationary machines and heavy-duty applications.
3. Radial piston motor with adjustable displacement:
   Enables variable volume flow for speed control.
   Ideal for applications with varying loads.
   Application: Industrial equipment and vehicles with variable requirements.

Use of radial piston motors:

1. Mobile machinery and vehicles:
As a drive for crawler tracks, excavators and concrete pumps.
To drive harvesters, mowers and tractors.
In forestry machines such as cable winches or log splitters.

2. Industrial applications:
In heavy-duty cranes and lifting systems to move heavy loads safely.
In conveyor technology as a drive for conveyor belts and turntables.
Control of large rollers and presses in rolling mills and in steel production.

3. Shipping and offshore:
For ship drives in controllable pitch propellers, winches and for driving anchor chains.
On oil rigs to drive drilling rigs and cable winches.

4. Wind energy and renewable energies:
Pitch control in wind turbines for torque control of rotors.
Hydraulic generator drives for efficient energy conversion.

Advantages of radial piston motors:

• High torque at low speeds. Particularly suitable for heavy-duty applications.
• High efficiency due to low internal friction losses.
• Robust and durable and therefore particularly suitable for harsh environments.
• Infinitely variable speed control is achieved by adjusting the oil flow.
• Radial piston motors can easily change the direction of rotation.
• The motors can absorb high load peaks for short periods.

Radial piston motors are the first choice for applications with high torque and low speed. They are particularly suitable for heavy-duty and industrial applications where robust, durable and powerful drives are required. Despite their higher weight and more complex design, they offer excellent efficiency and a long service life.

Here are the most important aspects to look out for when buying radial piston motors:

Purchasing radial piston motors requires a thorough analysis of technical specifications, economic factors and logistical conditions.

• Carefully determine the technical requirements necessary for the application:
• Torque (Nm): Determine the torque required for your application.
• Select a suitable speed, as radial piston motors are optimized for low speeds.
• Check whether the motor is compatible with your hydraulic system (typically: 100-450 bar).
• Determine the required hydraulic volume flow.
• There are different types depending on the application:
• Internal rotor radial piston motors are compact and have a high power density. They are suitable for mobile applications.
• External rotor radial piston motors have the highest efficiency and the highest torque. They are ideal for heavy industrial systems.
• Adjustable radial piston motors enable variable torque and speed control.
• High efficiency reduces energy losses and saves operating costs.
• The low internal friction minimizes wear.
• Optimum heat dissipation is important for continuous operation and high-load applications.
• Check whether the connections are compatible with your hydraulic pump.
• Do the flange or shaft connections match your machine?
• Is precise control via proportional valves possible?
• Check certifications such as ISO 9001 (quality management) or ATEX (explosion protection).
• Pay attention to CE marking and compliance with the Machinery Directive 2006/42/EC.
• Look for high-quality materials such as hardened steel or wear-resistant alloys that extend the service life and offer protection against corrosion.
• High-quality seals prevent leaks and increase service life.
• Low-wear bearings and pistons reduce maintenance costs and downtimes.
• Is there a simple maintenance option without special tools?
• Are spare parts such as seals, pistons and bearings readily available?
• Does the manufacturer offer service or maintenance contracts?
• Compare prices and possible discounts.
• Efficient motors reduce oil consumption and energy costs.
• Durable motors save maintenance costs in the long term. Does the manufacturer offer service or maintenance contracts?
• How many operating hours does the manufacturer specify?
• Is there a warranty period of 12-24 months or more?
• Are the motors available for immediate delivery or are there long waiting times?
• Are there alternative models if the desired motor is not available?
• Do the motors comply with relevant safety guidelines?
• Check whether the motors are suitable for use in potentially explosive atmospheres (ATEX)
• Is the motor protected against overload and overheating?
• Check whether additional safety devices (e.g. pressure relief valves) are required?
• Check whether the motor has an environmentally friendly design and whether biological or environmentally compatible hydraulic oils are compatible.

When purchasing radial piston motors, technical specifications, quality, costs and environmental aspects should be carefully analyzed. Thorough manufacturer research will help reduce long-term costs and achieve the best performance for your application.

Radial piston motors can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Radial piston motors from all over the world can be found on Exportpages.