The internal air gap measurement equipment for dynamic pressure motor

The size of internal air gap of dynamic pressure motor is an important index to determine its performance and running stability. In order to improve the precision and automation degree of the internal air gap measurement for dynamic pressure motor, an automatic measurement equipment was developed based on modular design concept. The equipment was mainly composed of clamping module, automatic forcing module, and displacement measurement module. During measurement, the stator was mounted by clamping module with a flexible support at two ends. Then an external force was loaded by forcing module, which was a 3-D electric precision motion platform integrating one triaxial force transducer. A relative displacement was generated because of the internal air gap. And the relative displacement increased until the rotor and stator touched each other. Thus the air gap was transformed into an external micro displacement. Finally, the displacement was measured by measurement module, a 2-D precision motion platform integrating double inductive probes, with relative measurement principle. Experimental results showed that the measurement accuracy was about 0.2μm.