End of line testing for double and single clutches in heavy duty applications
When standard isn’t enough: This custom-built test rig for truck clutches is designed to handle extreme mechanical forces, high precision requirements, and complex testing scenarios. High-performance End of Line (EoL) test rigs are critical for validating component functionality and quality prior to delivery. In many projects, our customers benefit from our modular EoL platform, which covers a wide range of driveline components – from electric axles and gearboxes to hybrid modules and clutches.
However, some applications demand more. For instance, in the development and validation of heavy-duty components, standard platforms often reach their limits – particularly when extreme forces, highly dynamic actuators, and specialized sensor setups are required.
One such application is the development of a dedicated EoL test rig for truck clutches. In this case, a completely custom solution was necessary. While key principles from our platform – such as robust construction, automation, and high data transparency – remain relevant, the test rig was designed from the ground up to meet the mechanical and functional challenges of heavy-duty clutch testing.
Versatile testing scenarios for the function and part parameters
Our EoL test rig for truck clutches facilitates the development of new clutch systems by verifying components through test runs focused on function and durability. Equipped with a telemetry system, it measures clutch temperatures up to 400 °C at 10 non-contact measurement points. It also features precise torsional moment transducers to measure torques up to 10,000 Nm with an accuracy class of 0.05%.
Test setups accommodate clutch dimensions up to 430 mm, enabling the following test scenarios:
- Friction torque test
- Vehicle run-up test (in different modes)
- Transfer torque at different clutch release bearing positions
- Brake wear test
- Constant torque wear test
- Wear-resistant test
The test bench is also capable of carrying out the necessary curve analyses, such as:
- Torque at the exact moment when the drive axle starts to rotate to determine the static friction coefficient
- Flywheel mass cycle with defined closing speed
- Measurement of the disengagement force before and after a test
Machine data and process flow
The testing process begins with manual pre-fixing of the clutch onto a special mounting plate, ensuring optimal preparation. An innovative quick-fixing system allows the prepared mounting plates to be efficiently attached to the test stand, significantly reducing setup times and enabling more frequent test cycles.
To specifically handle truck clutches, the test rig is equipped with high performance components to adapt to the higher force applied to the component, such as:
- A large main drive with a power input of 900 kW, providing a torsional moment of up to 10,000 Nm
- The option to variably equip the inertia
- The ability to actuate the clutch either with a servo-hydraulic loading unit up to 20 kN (2 tons) or, for other clutch variants, with a proportional pressure control valve up to 10 bar
- The machine bed and drive trains are FEM-calculated (finite element method) to ensure long-term mechanical stability
While the design philosophy draws on our modular EoL approach – focusing on robustness, precision, and efficiency – this system is a tailor-made solution, engineered to meet the extreme requirements of heavy-duty clutch testing.
Safety, monitoring, and data integration
The system places high priority on safety and process reliability:
- Retractable safety covers
- Real-time vibration monitoring to detect setup errors or component failure
- Continuous torque monitoring compared against expected values to flag deviations early
In the event of anomalies — such as unexpected imbalance — the machine stops the test sequence automatically, ensuring protection of both the test object and the system itself
All test results are directly transmitted to our measuring system, ensuring immediate analysis and seamless integration. The intuitive Human Machine Interface (HMI) provides a dynamic graphical display of the current machine status and sensor values, offering comprehensive and real-time monitoring at a glance. Measuring curves and detailed tables showcase all measured values, all made available through real-time data collection.
April 2025
