Rotary actuator, torsional fatigue test bench


The most advanced rotary torsional fatigue test bench is a crucial factor for production quality assurance and new product development. The reliability of stress and fatigue strength in materials, components and assemblies have become the fundamental condition for high quality levels. To cope with automotive, aerospace, military and other industry new quality requirements, the high speed with hydrostatic bearing and servo hydraulic performance hydraulic servo rotary cylinder is very suitable for rotary torsional fatigue test bench and high dynamic applications.

The rotary torsional fatigue test with rotary actuator can be performed on automotive propeller shafts, axle shafts, axle housings, crankshafts, ball joints, couplings and other rotary parts using in automobiles, aircraft, carriages, electric motors and machines. The fatigue tests can perform static load and dynamic load which should be configured independently. Electro hydraulic servo test tables bench with angle and (or) torque control are used for static, quasi static and fatigue component testing under pure torque loads.

The torque generating by a rotary actuator is associated with the component-under-test through a rigid coupling. This structural design can basically eliminate the load superposition by bent loading and lateral force and the impact of misalignment. Through the fixture adapter, the specimen fixture can be quickly and easily connected. It is suitable for a variety of alternating torque applications. Various measurement data can be detected by encoder, angle sensor, torque sensor and pressure sensor.


(1) Torsional actuator, (5) Test piece


The torsional fatigue test bench uses the servo hydraulic cylinder or servo electric cylinder to perform torsional fatigue loading on the test piece. The loading type is flexible and diverse, such as sine wave, triangle wave, linear, random wave, load spectrum input, etc. Waveform parameters are user definable. Multiple loading heads can operate synchronously or with certain phase difference. The torsional fatigue test bench system includes various loading methods such as tension, twist, and combination.

The measurement and control system adopts advanced digital servo control mode and high precision closed loop control, which can provide accurate and reliable control and data monitoring. The system also provides reliable fatigue failure determination methods, such as stress and strain monitoring, to capture the fatigue failure of the test piece.


Gearbox closed loop rotary torsional fatigue test bench


In a closed loop rotary torsional fatigue test bench, all torque loaded components form a mechanical closure system which is driven by an external drive unit such as motor providing necessary torque. Due to the gear engagement or bearing friction for friction, the closed power flow system generates power loss, but the power loss can be basically compensated by the external drive unit.

In a closed system, the torque is applied by a rotary actuator. If the built-in installation method is applied, the drive shaft should be divided into two parts and rotary actuator is installed in the cross section. If the cantilever installation method is applied, the rotary actuator is suspended at the end of the shaft.



Rotary torsional fatigue test bench can complete heavy-duty vehicle transmission’s


  • Fatigue life test
  • Efficiency test
  • Run-in test
  • Gear wear test


Large drive shaft torsional fatigue life test bench projects


  • Driving shaft, axle, coupling static torsional rigidity test bench
  • Driving shaft, axle, coupling static torsional strength test bench
  • Drive axle assembly static torsional test bench
  • Drive axle assembly bevel gear support rigidity test bench


Heavy-duty transmission parts rotation test bench projects


  • Transmission shaft torsional fatigue test bench
  • Transmission parking gear and click fatigue test bench
  • Click spring assembly durability test bench

How does a rotary actuator work?


A circular ring chamber is formed between the hollow cylinder and shaft. By using the rotary vane fixing on the shaft and partition fastening to the housing, the circular chamber is divided into two working chambers. If one working chamber is pressurized by hydraulic pressure, a torque is then generated. The torque on the reciprocal side is created when another working chamber is pressured. This makes the cylinder performing desired rotary movement on the drive shaft.

The latest highly dynamic rotary actuator is developed to meet the growing demands on high-frequency swivel movements, especially in the field of test rig technology. This series actuators have an axial and radial hydrostatic bearing on the output shaft. Through the experience and the co-engineering with our customers, a cylinder has been developed which allows the sufficient internal oil exchange in ​​high frequency area.

This series of rotary actuator can provide the ideal combination of torque and frequency due to the high power density. This can create the new standards in modern test rig technology.


High speed rotary actuator for torsional fatigue test bench


1. Hydrostatic storage

  • Perfect for very high speed
  • Optimized fluid exchange within the drive
  • Wear free
  • Very long service life


2. Two chamber system

  • Double acting drive
  • More torque at specified pressure
  • Drive is better balanced and therefore more even


3. Sealed design

  • Minimization of wear
  • Reduction of heat generation
  • Very long service life without maintenance or change of wear parts


4. Valve block

  • For servo-hydraulic control
  • DIN ISO standardized connections
  • Minimizes the length between the valve and the pressure chamber


ModelMaximum operating pressure (bar)Specific torque (Nm per bar)Maximum torque (Nm)Max. rotating speed (° per sec)Clamping angle (°)

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