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This is what characterises our servo hydraulic actuator :
  • Optimal price-performance ratio
  • Suitable for testing tasks with long strokes
  • As single-rod or double-rod cylinder
  • With integrated position transducer
  • Low dead weight
  • Optionally with mounting plate for control valve

Sensor technology and valves for servo hydraulic actuators
Perfect for dynamic industrial and testing tasks

For the necessary sensitivity, Hänchen offers suitable sensor technology components and valves – everything for highly dynamic, precise drives with high energy density.

Force transducer

Force transducers use strain gauge or piezo technology and measure the tensile and compressive forces of the hydraulic cylinder. They are mounted directly to the piston rod and thus measure the load on the piston rod statically or dynamically. Force transducers are used, for example, to monitor or control the cylinder force.

Force transducer work on strain gauge or piezo technology and measure the tensile and compressive forces of the hydraulic cylinder
Valves

Control valves regulate the flow rate in proportion to the electrical control signal. Depending on the application, valves with hydraulic pilot control or valves directly controlled by a proportional solenoid are used. Valves with zero overlap of the valve control edges are particularly suitable for hydraulic control tasks.

Continuous valves for Hänchen servo hydraulic actuator
Proximity switch

Pressure-resistant inductive proximity switch detect the end positions of the stroke in the hydraulic cylinder without contact or wear. The signal is used to control or monitor the hydraulic cylinder. Hydraulic cylinder with proximity switches also have adjustable cushioning.

Pressure-resistant inductive proximity switches detect the end positions of the stroke in the hydraulic cylinder, operating without contact or wear.
Position transducers

Position transducers electronically indicate the position of the piston rod. An analogue or digital position signal can be generated via the stroke. This can be used, for example, as an actual value signal in the position control circuit or for monitoring limit values of position or speed. The position transducer can be integrated directly into the cylinder, creating a mechanically protected system in a compact design.

Hydraulic cylinder with position transducers

Condition Monitoring
for hydraulic cylinders

For the operation of the hydraulic cylinder in an Industry 4.0 environment, additional sensors can provide data for condition monitoring:

  • Pressure transducer in the chambers analyse the friction behavior
  • Temperature and color sensors provide information on the condition of the fluid
  • Online particle counters indicate the degree of contamination of the system
  • Flow sensors on the functional oil channel provide an indication for a seal replacement.

Series of servo hydraulic actuators from Hänchen
For controlled movements

Servo hydraulic actuator series 120
  • bore 40 mm to 180 mm
  • working pressure up to 150 bar
  • as single-rod cylinder and double-rod cylinder
  • cylinder in round-head design
  • various mounting types
  • honed and chrome-plated piston rod
  • test pressure = 1.5 x max. working pressure
Servo hydraulic actuator series 160
  • bore 50 mm to 125 mm
  • working pressure up to 160 bar
  • as single-rod cylinder
  • cylinder in round-head design according to ISO 6020-1
  • various mounting types
  • honed and chrome-plated piston rod
  • test pressure = 1.5 x max. working pressure
Servo hydraulic actuator series 300
  • bore 50 mm to 140 mm
  • working pressure up to 300 bar
  • as single-rod cylinder and double-rod cylinder
  • cylinder in round-head design
  • various mounting types
  • honed and chrome-plated piston rod
  • test pressure = 1.5 x max. working pressure
Test hydraulic actuator series 320
  • bore 28 mm to 320 mm
  • working pressure up to 320 bar
  • as double-rod cylinder
  • honed and chrome-plated piston rod
  • test pressure = 1.5 x max. working pressure

Hydraulic actuators are suitable for hydrodynamic applications. You can find out more about this under test actuator.

Suitability of the servo cylinder series according to frequency range

The required dynamics of the drive determine the cylinder's type of effect. With fast control valves, even single-rod cylinders achieve a high profile quality at high frequencies.

The limit values shown in the diagram are intended as guidelines for your design. They depend on various operating conditions - we will help you with your selection.

Suitability of the servo cylinder series according to frequency range

Equipment servo hydraulic actuator
Sealing and guiding systems

The sealing system in the cover and on the piston are the core of a hydraulic cylinder and determine its application possibilities. This defines the friction characteristics and stick-slip behavior of the industrial hydraulic cylinder, the achievable speeds, and how side loads affect it. For servo hydraulic actuators operated in an oscillating manner, we recommend the Servoslide® synthetic guide or PTFE wear rings as the guiding system in the cover.

Overview of sealing systems on the cover
Overview of sealing systems on the piston

Servoseal cylinder
The modern method of testing

By using our Servoseal® seals in the slim series 120 and 300, the need for massive test actuators is eliminated in applications with frequencies up to 25 Hz.

Your advantages at a glance:

  • Virtually no friction and therefore no wear
  • Function without leak oil flow at the cover and leakage across the piston
  • No minimum amplitude required
  • strokes from 1 mm to over 1,000 mm

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Servoseal cylinder
The modern method of testing

By using our Servoseal® seals in the slim series 120 and 300, the need for massive test actuators is eliminated in applications with frequencies up to 25 Hz.

Your advantages at a glance:

  • Virtually no friction and therefore no wear
  • Function without leak oil flow at the cover and leakage across the piston
  • No minimum amplitude required
  • strokes from 1 mm to over 1,000 mm

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Servoseal cylindersPlay video: Please activate the YouTube cookie.

Questions about Servoseal cylinders
Cost-effective test actuators for endurance tests

What is Servoseal® and what makes this seal special?

Servoseal® is a dynamic sealing system for pistons and covers, developed by Hänchen itself and tested on its own seal test stand. An integrated carbon retaining ring prevents the seal from being pressed too strongly against the sliding surface by the hydraulic pressure. As a result, Servoseal® combines very low friction with minimal leakage and is also suitable for tests with small movement amplitudes. This enables precise, energy-efficient, and economical test actuators with low flow rate requirements.

For many testing tasks, a test actuator with a Servoseal® sealing system is suitable. The Servoseal® significantly reduces leakage across the piston and cover and requires less flow rate compared to gap seals. This often allows for the use of smaller valves and hydraulic components, which lowers investment and operating costs. At the same time, the low friction ensures precise and energy-efficient movement. 

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Accessories and tools for servo hydraulic actuators
Mounting elements and system components

You can find our standard accessories and tools in the HÄKO product configurator to match your selected cylinder.

Accessories
Hydraulic cylinder accessories

Do you need suitable accessories for your servo hydraulic actuator?
We can supply you with:

  • spherical rod eyes
  • circular flanges
  • mounting plates
  • clevis brackets
  • screws
    and much more
More information about mounting elements
Control block: Hydraulic block with valves
Control block

Is reliable hydraulic control necessary for the functional actuation of your hydraulic cylinder?
The control block integrates the required valves, e.g., for 

  • Activation: jerk-free and smooth start-up
  • Shut-off: Disconnecting drive axles from the fluid supply
More information about the control block
Technical data of servo hydraulic actuators
for industrial and test applications

Type of effect: single-rod cylinder, double-rod cylinder | Sealing systems: Basic design, Servocop®, Servoseal®*, Servofloat® |
Speeds: up to 2 m/s | Stroke: 1 - 1,500 mm

Series 120 Series 160 Series 300
Bore
(mm) 		Rod Ø
(mm) 		Force F1 | F2
(kN)
 Max. pressure**
(bar)		 Force F1 | F2
(kN)		 Max. pressure**
(bar)		 Force F1 | F2
(kN)		 Max. pressure**
(bar)		  
40 25 18,8 | 11,5 150 --- --- --- ---
50 25
28
30
40		 29.5 |
---
29.5 |

 22.1
---
18.8
---		 150
---
150
---
31,4 |


 ---
21.6
---
---		 ---
160
---
---

58.9 |
58.9 |		 ---
---
37.7
21.2		 ---
---
300
300
60 30
40
50		 42.4 |
42.4 |

 31.8
23.6
---		 150
150
---

---
---
---		 ---
---
---
84,8
84,8		 ---
47.1
25.9		 ---
300
300
63 36 --- --- 49,9 | 33,6 160 --- ---
80 40
45
50
60		 75.4 |

75.4 |

 56.5
---
45.9
---		 150
---
150
---
80,4 |		 ---
55.0
---
---		 ---
160
---
---

150.8 |
150.8 |		 ---
---
91.9
66.0		 ---
---
300
300
100 50
56
60
80		 117.8 |
---
117.8 |

 88.4
---
75.4
---		 150
---
150
---
125,7 |


 ---
86.3
---
---		 ---
160
---
---

235.6 |
235.6 |		 ---
---
150.8
84.8		 ---
---
300
300
125 60
70
80
100		 184.1 |

184.1 |

 141.7
---
108.7
---		 150
---
150
---
196,3 |


 ---
134.8
---
---		 ---
160
---
---

368.2 |
368.2 |		 ---
---
217.4
132.5		 ---
---
300
300
140 80
100		 230.9 |
230.9 |		 155,5
113,1		 150
150		 ---
---		 ---
---
461,8 |		 ---
226.2		 ---
300
160 80
100		 301.6 |
301.6 |		 226,2
183,8		 150
150		 ---
---		 ---
---
603,2 |		 ---
367.6		 ---
300
180 100
120		 381.7 |
381.7 |		 263,9
212,1		 150
150		 ---
---		 ---
---
763,4 |		 ---
424.1		 ---
300
200 100
120
140		 628.3 |
628.3 |

 471.2
402.1
---		 200
200
---		 ---
---
---		 ---
---
---

942,5 |		 ---
---
480.7		 ---
---
300
220 120
140
160		 760.3 |
760.3 |

 534.1
452.4
---		 200
200
---		 ---
---
---		 ---
---
---

1.140,0 |		 ---
---
537.2		 ---
---
300
250 120
140
180		 981.7 |
981.7 |

 755.6
673.9
---		 200
200
---		 ---
---
---		 ---
---
---

1.472,0 |		 ---
---
709.2		 ---
---
300
300 160
200		 1.413,7 |

 1,011.6
---		 200
---		 ---
---		 ---
---
2.120,6 |		 ---
1,178.2		 ---
300

* Not for series 160
** When pivot mounting the pressure is limited to 120 bar.

F1 = force extending when extend the cylinder | F2 = force retracting when retraction the cylinder
For double-rod cylinders, retracting and extend correspond to the value F2.

APPLICATION REPORT
Wing test stand / Aircraft industry
APPLICATION REPORT
Material Test Stand / Aircraft Industry
APPLICATION REPORT
Grinding machine / Railway industry
APPLICATION REPORT
Cooling bed in the rolling mill / Steel mill
APPLICATION REPORT
Blade angle adjustment / Wind turbines
APPLICATION REPORT
Low-pressure die casting plants / Foundry

FAQ - servo hydraulic actuator
Technical questions on application

Which position transducers and interfaces are available for Hänchen servo hydraulic actuators?

Our servo hydraulic actuators are available with various position transducers and interfaces to ensure flexible integration into your control system (PLC/IPC). As standard, we offer analog interfaces (+/- 10V or 4-20 mA) as well as digital, absolute interfaces such as SSI, CANopen, EtherCAT, or Profibus DP.

The selection of the control valve is a compromise between dynamics, control accuracy, and cost. For highly dynamic applications, servo valves with a high response frequency are suitable. For less demanding positioning tasks, proportional valves with integrated electronics can also be a good and economical alternative. It is important that the nominal flow rate (flow rate) of the valve is matched to the cylinder and the required speed.

Servo hydraulic actuators are found wherever force, motion, and position need to be precisely and dynamically controlled. Classic examples include: Material test machines that apply defined load cycles to components; driving and flight simulators that generate realistic movements; presses with controlled processes; control dampers in power plants, or the control of roll gaps in the steel and paper industry.

What requirements does a servo hydraulic actuator place on the hydraulic fluid and its cleanliness?

For a long service life and consistently high control quality, fluid condition is of central importance. We recommend standard hydraulic oils according to DIN 51524 with ISO VG 32 to VG 68. The oil cleanliness is crucial: For servo valve applications and gap sealing systems, we require a cleanliness class of at least 16/13/10 according to ISO 4406. Good filtration is the most economical insurance for your system. Particles in the oil can block the control valve and cause premature wear of the seals.

The decision depends on the application. Hydraulic servo hydraulic actuators demonstrate their strengths when very high forces are required in a small installation space (high power density). They are extremely robust against shock loads and offer excellent heat dissipation via the hydraulic fluid. In applications with the highest demands on force control or very high load changes, hydraulics are often superior.

Depending on the control, a servo hydraulic actuator can regulate position, speed, or force. Many applications combine these control parameters, for example, precise positioning followed by force control. This allows complex motion sequences to be realized reliably and reproducibly.

General Mechanical Engineering Knowledge
on servo hydraulic actuators

What is a servo hydraulic actuator?

A servo hydraulic actuator is a hydraulic cylinder combined with a position transducer and controlled valve technology. This allows it to continuously monitor and precisely regulate its position, speed, or force. Unlike a conventional hydraulic cylinder, it does not just move between end positions but can precisely approach any desired position.

A servo hydraulic actuator operates in a closed control circuit (Closed Loop). The process is as follows:

  1. Setpoint Specification: The controller (e.g., a PLC) specifies a target position, speed, or force.
  2. Actual Value Acquisition: The position transducer integrated into the cylinder continuously measures the current position of the piston rod and reports this "actual value" back to the controller.
  3. Control Deviation: The controller compares the setpoint with the actual value. The difference is the control deviation.
  4. Actuating Signal: Based on this deviation, the controller calculates an actuating signal for the control valve.
  5. Action: The valve opens and directs a precisely metered oil flow rate into the corresponding cylinder chamber, causing the piston rod to move and minimizing the control deviation. This process repeats many hundreds or thousands of times per second.

The four most important key performance indicators are:

  • Positioning Accuracy: How precisely can the cylinder reach a specified target position?
  • Repeatability: How well can the cylinder repeatedly approach the same position? This is often more critical than absolute accuracy.
  • Dynamics/Response Behavior: How quickly can the cylinder react to a change in the setpoint? (e.g., measured in Hz).
  • Precise Control of Force and Speed: The fundamental performance parameters that define which load can be moved at what speed.
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