SEHB - hydraulic closed-loop controled brake for trams

  rendered hydraulic control unit Copyright: ifas

The actual braking torque of hydraulic disc brakes is directly dependent on the prevailing coefficient of friction and is therefore subject to strong fluctuations. With conventional brake systems there is no recording of the braking torque, so that control is not possible at present. The aim of this project is therefore the research, development and validation of prototypes of hydraulic-mechanical disc brakes with controlled braking torque.

Benefit Procedure
Reproducible braking effect

Function synthesis on the basis of brake systems relevant to practice

Optimal utilization of the potential braking power

Development of hydraulic-mechanical controllers for active and passive brakes

Minimization of environmental influences Verification on the ifas brake test bench

Equipment of a reference vehicle and verification



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Development and research of hydraulic brake torque control

Prototype of a control unit for passive rail vehicle brakes Copyright: ifas Prototype of a mechanical-hydraulic controller with mechanical rectification and fail-safe behaviour for a passive rail vehicle brake

Prototypes of the controller unit for rail vehicle brakesder

Braking torque control is developed using the example of rail vehicle brakes. Both active and passive brake types are being specifically investigated. To increase the robustness and reliability of the system, the complete implementation is chieved hydraulically-mechanically without electronic components.

  Response Surface conventional brake Copyright: ifas Parameter study: Responsesurface of the standardized braking torque of the uncontrolled (left) and the controlled system (right)

Simulative parameter study

The design and the verification of the functionality of the prototypes is first simulated in AMEsim™. Previous findings show a significantly lower scattering of braking torques. With controlled braking, the braking torque can be kept constant over a wide range of friction coefficients. Only when the physical limits are exceeded a drop in braking torque can be detected. A significant influence on the control has to be expected from the vertical brake disc offset resulting from the vehicle suspension.

  Draft of a brake test bench Copyright: ifas Brake Test Bench

Brake Test Bench

For the experimental investigation of the prototypes, a brake test bench is being developed which allows realistic operation in the full performance range of the brakes. The friction conditions at the brake pads can be specifically influenced by a wetting system.


Upcoming research on the controlled brake

In the further course of the project, the developed test bench will be set up, put into operation and then the prototypes of the brakes will be tested experimentally. The results will be used to verify the built up simulation and optimize the prototypes. After functional verification, an installation in a reference vehicle is planned in order to prove the functionality under real operating conditions.



The project „Schienenfahrzeugbremse mit hydraulisch-mechanisch geregeltem Bremsmoment“ (MU 1225/40-1) was financed by the Deutschen Forschungsgemeinschaft (DFG).

The successful implementation is made possible by the kind support of HANNING & KAHL GmbH & Co KG (H&K).

At this point we would like to express our explicit thanks to both the DFG and our application partner H&K.

  Copyright: DFG   Company logo Hanning & Kahl Copyright: H&K  


Bordovsky, Patik; Merkel; Philip Amos; Murrenhoff, Hubertus; Reinertz, Olivier; Schmitz, Katharina: Development of a Prototype Valve for a Hydro-mechanical Braking-torque Control used on Railway Disc Brakes, 2018, Ostrava/ 24th Internation Conference on Hydraulics and Pneumatics (ICHP2018)/ VŠB - Technical University of Ostrava

Bordovsky, Patrik;Adipoor, Sara Hamed; Murrenhoff, Hubertus; Reinertz, Olivier Georg: Simulation of an Active Disc Brake with a Hydro-Mechanical Torque Control , 2018, Samara,Russland/ 2018 Global Fluid Power Society PhD Symposium, GFPS2018

Merkel, Philip Amos; Murrenhoff, Hubertus* ; Reinertz, Olivier Georg* ; Schmitz, Katharina:

Hydro-Mechanical Closed-Loop Brake Torque Control for Railway Disc Brakes, 2020, 2nd International Railway Symposium Aachen, IRSA 2019, 2019-11-26 - 2019-11-28, Aachen, Germany, Seiten/Artikel-Nr: 594-607