High accuracy while maintaining necessary torque overload ranges
Transmission test stands encounter large transient torque loads, particularly on the output driveline. During development, shift tuning events can ring the driveline resonances. The peak torques generated can be as much as 8 to 10 times the initial loading. Inadequately sizing the transducer for these overloads can result in driving the signals into the nonlinear range of the sensor, causing erroneous transient signals and measurement errors, and potential damage to the sensor. HBM’s T10F and T32 FNA products provide the high accuracy required over full range, while maintaining the overload capability Allison need.
Multiple torque ranges for increased resolution and accuracy of low measurement ranges Transmission development is frequently characterized by spin losses of the unit under test. These drag torque measurements are minuscule compared to the nominal torques of the input and output.
Traditionally, a low range torque transducer would be installed, or a separate test stand would be used to measure these spin losses. Setups on the test stand are time consuming and costly. Therefore, a transducer with high resolution and accuracy over both high and low ranges is desirable.
Using HBM’s PME MP60 measuring amplifier, Allison is able to have the transducer calibrated for two (or more) ranges and scale the output for increased resolution to their data acquisition system. Thus, the low torque range accuracy is improved for precise determination of spin losses, without the need for a secondary transducer change or alternate test setup.