In-Process Measurement of Contact Pattern Variations in Rotating Main Bearing of Machine Tools Using Ultrasonic Waves Method.

Abstract

It can be pointed out that characteristics of machine tool joints have a significant effect on the static, dynamic and thermal behavior of a machine tool as a whole. To clarify various characteristics of the joint, it is basically essential to evaluate the contact pressure and its distribution. With regard to the measurement of the static contact pressure of the joint, one of the authors has already proposed a method using ultrasonic waves. In contrast, the joint behavior in the machine work condition is not revealed as yet. In this study, therefore, an ultrasonic waves method for the in-process measurement of contact pattern variations has been proposed, and its characteristics have also been investigated. The objective of the study is the joint between the bearing and its housing in the main spindle system. The method has a remarkable feature in that it is continuously applicable in operation without changing the state of contact at the joint. From the experimental results, it is ascertained that the proposed method is available for detecting the contact pattern variations significantly influenced by the thermal expansion of the outer ring of the bearing.