Sensor-embedded Linear Ball Bearing for Linear Guide Way Pre-load and Straightness Monitoring

A cost-effective sensor-embedded smart linear guideway type (LGT) recirculating linear ball bearing is proposed. Two kinds of sensors are installed on this linear ball bearing. The first one is an optical mouse sensor which provides the positioning information. The second one is a tactile load cell, called Force Sensitive Resistor (FSR) which measures the forces from the guide ways. With these sensors, the recirculating linear ball bearing is utilized to monitor the position and the onset of preload loss and, moreover; the straightness and parallelism of linear guide ways. By tracking the change of force sensed by the FSR along the guide way, the LGT linear bearing preload degradation and the guide way alignment can be on-line monitored automatically without taking off the worktable. The performance of this proposed sensor-embedded smart linear ball bearing is assessed experimentally.