HOERBIGER: Multi-component transducers for a transmission test rig

In industrial plants, usually only one load component is measured. Then extensive mechanical decoupling of the parasitic influences may be necessary.

Various transducer designs with different nominal (rated) measuring ranges and nominal measuring range conditions are used for the components. HBM has developed a 2-component transducer for the synchronization process simulating test benches made by HOERBIGER, the transmission manufacturer and the associated components.

This has been designed in such a way that axial force and friction moment are acquired simultaneously. The transducer also had to fit in the tight mounting clearance of existing test benches and needed the input shaft to run through a central hole. The oil mist environment and the presence of hot oil surrounding the lower half of the test benches were major challenges for which HBM found a good solution. The transducer achieves extremely good accuracy, with a composite error of ≤ 0.05 % f. s. and an equally low reversibility error.

Temperature sensitivity during operation, when the oil reaches temperatures of up to 110 °C, is also extremely low. Very good stability is certified during the entire service life test of several thousand cycles. The crosstalk, that generally limits the accuracy of multi-component transducers, has been minimized in all phases of development and manufacture. In order to further reduce measurement error during operation, an individual compensation matrix is needed for each multi-component transducer. This is included in the scope of supply, together with the sensitivity and the crosstalk as a percentage.

The output basis for the compensation matrix is the straight lines determined from the measured values, in accordance with the best-fit method.