Bearing state diagnostic apparatus

Abstract

Provided is a bearing state diagnostic apparatus in which a sound generated from a bearing (21-23) is detected by a sound sensor (75), a detected value of the sound sensor (75) is compared with data which was previously formed, thereby diagnosing a state of the bearing (21-23), wherein at least one sound sensor (75) is disposed at a position separated away from an outer surface of a cylindrical support body (12, 24, 25) in which at least one bearing (21-23) is accommodated, the corresponding bearing (21-23) and sound sensor (75) are in communication with each other through a detection sound propagation path (71-73).

Description

technical field [0001] The present invention relates to a bearing state diagnosis device that detects, for example, a sound generated by a rolling bearing that supports a main shaft of a machine tool, and diagnoses the state of the rolling bearing based on the detected detection value. Background technique [0002] Bearings are used in many mechanical rotating machines, etc. Among bearings, rolling bearings are generally composed of an inner ring, an outer ring, a plurality of rolling elements, and cages for holding the rolling elements at equal intervals. The inner ring rotates with the shaft, and the outer ring is assembled and fixed on the housing. The bearing is filled with lubricating oil or lubricating oil is supplied to the bearing. During the rotation of the main shaft, an oil film is formed between the inner ring and the outer ring and the rolling elements. [0003] Although there is no problem when the bearing rotates normally, there may be cases where the machine...

AI Technical Summary

Problems solved by technology

In this case, compared with a machine of the same structure that does not incorporate a sensor when the machine is assembled, it is necessary to perform wiring processing and sensor fixing, which generally increases the number of assembly man-hours. In addition, when the sensor fails and needs to be replaced , there is the possibility that more time must be spent

Moreover, since it is necessary to select a smaller sensor according to the size and structure of the machine, there may be problems such as high sensor price, unsatisfactory performance, and few types of options.

In addition, when the machine is composed of a plurality of bearings, the same number of sensors as the number of bearings is required, so there are problems such as high device cost and complicated components of the device and machine.

However, if the installation position of the sensor is separated from the vicinity of the bearing, for example, by assembling the outer circumference and end surface of the housing, the replacement of the sensor and the simplification of the components can be realized, but the S / N ratio is lowered.

In this case, of course, it is difficult to install a sensor on each bearing, and it becomes a structure in which one sensor diagnoses multiple bearings. Similarly, if a machine is composed of multiple bearings with similar specifications, there may be difficulties. Judging which bearing has a problem, etc.

[0006] In JP-A-2005-164314, even if it is a device that uses a sensor that can detect sound to diagnose the state of the bearing, since the change in the pressure transmitted in the air is measured, if the position of the sensor is far away from the For bearings, there is a possibility that the S / N ratio may decrease due to the influence of the sound around the machine, the sound from other than the bearing, the air temperature around the machine, etc.

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