Yutaka Igarashi

Effects of Grease Types on Vibration and Acoustic Emission of Defective Linear-Guideway Type Recirculating Ball Bearings

In this paper, vibrations and acoustic emissions (AEs) of defective linear-guideway type recirculating ball bearings under grease lubrication were measured. The experimental results show that the vibration and AE amplitudes (the pulse amplitudes, the RMS values) of both the normal and defective bearings have a tendency to be reduced when a grease with higher base oil viscosity is used. Under the same type of grease, the RMS values of the vibrations and AE of the defective bearings increase as the defect angle increases. However, the increases of the RMS values due to increased defect angle are reduced when a grease with higher base oil viscosity is used.Copyright

Effects of Ball Groupings on Ball Passage Vibrations of a Linear Guideway Type Ball Bearing (Pitching and Yawing Ball Passage Vibrations)

The effects of ball groupings on the pitching and yawing ball passage vibrations of linear guideway type ball bearings (linear ball bearings) under low speed operation were studied. For this study, the test linear ball bearings (which can retain the ball grouping in operation) with three types of ball groupings were manufactured, and the pitching and yawing ball passage vibrations of each test linear ball bearing were measured using a laser autocollimator. Moreover, a calculation method of the ball passage vibrations for a linear ball bearing with an arbitrary ball grouping was presented. According to the presented method the ball passage vibrations for three types of ball groupings were calculated. The experimental and calculated results show that the occurrence of the pitching and yawing ball passage vibrations was affected by the ball groupings. For the occurrence, the waveforms, and the amplitude of the pitching and yawing ball passage vibrations for the ball groupings, the calculated results based on the presented method almost matched with the experimental results.Copyright

Vibration and Acoustic Emission of Linear-Guideway Type Recirculating Linear Ball Bearings With One Artificial Defect in the Carriage

In machines with linear-guideway type recirculating linear ball bearings (linear bearings), to prevent shutdown of machines caused by unexpected-failures of linear bearings, there has been an increasing demand for the development of defect (especially flaking) detection techniques of linear bearings by using vibration or acoustic emission (AE) measurements. Although studies [1–3] on vibrations of linear bearings without defects have been carried out, work on vibrations and AE of defective linear bearings are few [4, 5].Copyright