Bearing diagnostic device for machine tool

Abstract

The invention provides a bearing diagnostic device for a machine tool. The device is capable of detecting abnormality of a bearing in a precise and low-cost manner at an early time prior to possible damage to a machine tool. The bearing diagnostic device includes a rotation speed detector and a calculating apparatus which detect the rotation speed of a spindle at a certain specific rotation speed; a temperature sensor and a calculating apparatus which detect the temperature of the spindle; a friction torque calculating part which calculates a friction torque of the bearing; a rolling speed calculating part which calculates the rolling sped of the bearing; a bearing pre-pressing estaimation part which estimates the pre-pressing of the bearing; a lubricant viscosity estimation part which estimate the lubricant viscosity of the bearing; a bearing characteristics calculating part which, based on the friction torque, the rolling speed, the pre-pressing, and the lubricant viscosity, calculates bearing characteristics; a storage apparatus which stores a reference bearing characteristics; and a determination apparatus which compares the bearing characteristics calculated by the bearing characteristics calculating part and the reference bearing characteristics stored in the storage apparatus, and determines the presence of abnormality.

Description

technical field

[0001] The present invention relates to a bearing diagnostic device for detecting abnormality of a rolling bearing used for a shaft support of a rotary shaft on a machine tool. Background technique

[0002] In a rotating shaft device having a rotating shaft such as a spindle installed in a machine tool, a rolling bearing (hereinafter simply referred to as a "bearing") for supporting the rotating shaft includes an inner ring, an outer ring, and a plurality of bearings arranged between the two rings. The rolling elements (rollers, etc.) and the cage for keeping the distance between the rolling elements, the inner ring rotates integrally with the rotating shaft, and the outer ring is fixed by being fitted into a main shaft housing or the like.

[0003] Examples of abnormalities occurring in this bearing include poor lubrication, contamination of foreign matter, abrasion, excessive load, and the like. If these abnormalities occur, poor rotation or thermal sticki...

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