JPH01221633A - Composite sensor for bearing fault detection - Google Patents

Abstract

PURPOSE:To make a warning display and also display abnormal vibration before the temperature of a bearing, etc., reaches its critical temperature by detecting the variation rate of the ambient temperature and vibration of the bearing. CONSTITUTION:A head 11 which is applied to an object of measurement is fitted with a flat plate type link 12 which has a tail 13 atop in a cantilever shape. Said link 12 and tail 13 function as a spring and a mass for detecting the vibration. Thermocouple groups 15a-15d are fitted on the surface of the link 12 and connected in a bridge shape. For the purpose, the temperature difference between the head 11 and tail 13 is detected by said bridge connection to measure the temperature variation rate of the head 11. A warning is therefore generated before the temperature of the bearing, etc., reaches its critical temperature. Further, the vibration of the vibrator consisting of the link 12 and tail 13 is detected to detect the abnormal vibration of the bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a composite sensor for detecting bearing failure, which detects failure based on the temperature change rate, vibration, etc. of the bearing.

[Prior art] In conventionally known bearing abnormality monitoring devices,
Normality or abnormality is often determined based on information about the temperature or vibration of a bearing, and in many cases, a threshold value of the temperature or vibration level + α value under normal conditions is simply set and input. If the signal value exceeds this value, a signal is issued to notify of an abnormality or the machine operation is stopped.

On the other hand, the rate of temperature change, that is, the rate of temperature change, can also be effectively used to monitor abnormalities in the bearing. This temperature change rate is a differential value of temperature with respect to time, and can be determined digitally or electrically. If this information is used as information for temperature control, etc., it is possible to predict future trends in temperature change, and therefore it is possible to make early decisions regarding abnormal temperature rises, etc.

However, digitally differentiating signals generally requires expensive equipment, and electrically differentiating signals requires an electrical differentiation circuit that is susceptible to noise. To deal with these problems, Nara et al. developed a temperature change rate sensor as shown in Fig. Proceedings of the Physical Society of Japan Academic Conference (see J).The sensor has a cylindrical cross-section i as shown in the same figure, and consists of a head 1 that touches the object to be measured, a link 2 attached to the head, and a link 2 attached to the head. It consists of a tail 3 attached to the tip of the link and a cover 4 that keeps the inside in a vacuum and thermally isolates it from the outside.In this case, the temperature difference between the head l and the tail 3 is the temperature of the head l and the tail l. The value is approximately proportional to the temporal rate of change of Thermocouples are used.

As mentioned above, this temperature change rate sensor can be effectively used to detect abnormal temperature rises in bearings, but
It cannot be said that bearing abnormalities can be effectively detected by simply detecting the rate of temperature change, and it is necessary to use a vibration sensor or the like in combination.

[Problem M to be solved by the invention] The technical problem of the present invention is to use the temperature change rate sensor described above and make it possible to detect vibration and temperature by making some modifications to it, and to detect bearing failures early. The purpose of this invention is to obtain a composite sensor for bearing failure detection that makes possible the following.

[Means for Solving the Problems] In order to solve the above problems, the temperature change rate sensor of the present invention is provided by attaching a link with a tail at the tip in the form of a cantilever to the head that touches the object to be measured. and the tail serve as a spring and mass that constitute a vibrator for detecting vibrations, thermally isolated from the outside by a cover,
A group of thermocouples that measure the temperature difference between the head and the tail and function as a thin metal wire strain gauge are attached to the surface of the link, and a part of the group of thermocouples can be used for temperature detection.

[Function] If the head of the composite sensor is operated with the head attached to or near a part of the bearing, and the temperature difference between the head and the tail is measured as the temporal rate of change in the temperature of the head using a group of thermocouples, the bearing, etc. It becomes possible to issue a warning or reduce the load by predicting the point in time when the temperature will reach a certain dangerous temperature.

Additionally, if the thermocouple group is used as a thin metal wire strain gauge to detect the vibration of the vibrator made up of links and tails at the same time as the above temporal temperature change rate, the same measures as above can be taken due to abnormal vibration. becomes possible.

Furthermore, when the temperature of the bearing gradually rises to a dangerous temperature, the temperature is detected by a part of the thermocouple, and similar measures are taken when the temperature exceeds a certain threshold. Can be done.

[Embodiment] FIGS. 1 to 4 show an embodiment of a composite sensor for bearing failure detection according to the present invention.

This composite sensor for bearing failure detection is intended to detect a bearing failure in the t period, and is capable of detecting the temperature change rate, vibration, and even temperature of the bearing with a single sensor. In other words, by knowing the rate of temperature change around the bearing,
Before the temperature of the bearing, etc. reaches the dangerous temperature, it is predicted that it will reach the dangerous temperature after a certain time, and the same sensor will also detect vibration, and even if there is no risk of reaching the dangerous temperature, the vibration will be detected as abnormal. If it is large, a signal indicating an abnormality is output. Furthermore, if the temperature rises very gradually but continuously and reaches a dangerous temperature, it cannot be detected using the above temperature change rate, so thermocouples that measure the local rate of change are used to measure the temperature in proportion to the temperature. This outputs a signal that

The configuration of the above bearing failure detection sensor is shown in Figures 1 and 2.
As shown in the figure, a flat plate-like glue 12 with a tail 13 at the tip is attached in a cantilever shape to the head 11 that is applied to the object to be measured, and the cover 14 covers them airtight to create a vacuum inside. thermally isolated from the outside. The link 12 and tail 13 function as a spring and mass that constitute a vibrator for detecting vibrations.

To measure the temperature difference between the head it and the tail 13, which is approximately proportional to the temporal rate of change in the temperature of the head 11, as shown in FIG.
5a - 15d and connect them as shown in Figure 4, the thermocouple group! Head It and tail occurring in 5a-15d! A direct current voltage proportional to the temperature difference of 3 is measured with a voltmeter 16 to determine the temperature change rate of the head 11. At the same time, the thermocouple groups 15a to 15d are connected in a Wheatstone bridge to connect thin metal wires using an alternating current carrier wave. Use it as a strain gauge.

As described above, the link 12 is a spring, and the tail 13 is configured to be able to detect vibrations of a penetrating vibrator. Also,
One element 17 of the same thermocouple group is used for temperature detection and is connected to a thermocouple thermometer.

In addition, the DC component flowing through the Wheatstone bridge for distortion measurement is cut with an external capacitor 18.
In the voltmeter 18 for measuring the rate of temperature change, the effects of the alternating current component of the carrier wave and noise are removed by averaging.

The thermal characteristics of the sensor are determined by the cross-sectional area and length of the link 12, the volume of the tail 13, the specific heat, and their thermal conductivity, and are also important characteristics as a vibrator for vibration measurement. The frequency is determined by the moment of inertia of the link 12, the length, the modulus of longitudinal elasticity, and the moment of inertia of the tail 13 relative to the head portion. Although these values may not always satisfy the conditions required for the above-mentioned sensor, depending on the relationship between the vibration frequency to be measured and the natural frequency of the sensor, it is possible to use the acceleration type, velocity type, or displacement type depending on the relationship between the vibration frequency to be measured and the sensor's natural frequency. It becomes possible to use it not only for precision measurement but also as a sensor for detecting bearing failures.

It is to be noted that it is advantageous to use vapor deposition, submerging, and knee etching techniques to fabricate the thermocouple groups 15a to 15d.

The composite sensor having the above configuration is used by installing the head 11 on a part of the bearing or in the vicinity thereof for the purpose of early detection of bearing failure.The voltmeter 16 mentioned above measures the temperature of the head 11 and tail 13. By measuring the difference as a temporal rate of change in the temperature of the head 11, before the temperature of the bearing etc. reaches a certain dangerous temperature, an alarm can be issued or the load can be reduced in anticipation of the temperature approaching the dangerous temperature. It becomes possible to take such measures.

Further, at the same time as the temperature change rate, thermocouple groups 15a to 15
Use d as a total bending wire strain gauge and link! By detecting the vibration of the vibrator composed of the bearing 2 and the tail 13, even if there is no risk of the bearing reaching a dangerous temperature, if the vibration is abnormally large, it is possible to take the same measures as described above. Become. In order to detect this vibration, it is necessary to attach the sensor to the bearing so that the flat surface of the flat link 12 is orthogonal to the direction of vibration.

Roughly speaking, if the temperature of the bearing increases very gradually but continuously and reaches a dangerous temperature, it is impossible to detect an abnormality based on the above temperature change rate, so only one pair of series thermocouples is used to set the reference junction to room temperature or A signal proportional to the temperature is taken out as zero degrees, and if the temperature exceeds a certain tXJ value, an alarm is issued.

It is possible to take measures such as reducing the load.

〔Effect of the invention〕

According to the composite sensor for bearing failure detection of the present invention described in detail above, a temperature change rate sensor capable of measuring the temperature difference between the head and the tail as a temporal change rate of the head temperature is used, and a slight modification is made thereto. By adding this, vibration and temperature can also be detected.

Bearing failures can be detected early.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the composite sensor for detecting bearing failure of the present invention, Fig. 2 is a plan sectional view thereof, Fig. 3 is a sectional view of the link in the above embodiment, and Fig. 4 is the link above. FIG. 5 is a cross-sectional view showing the structure of a known temperature change rate sensor. 11.Head, 12.Link, 13.Fist tail, 14-.Cover. 15a-15d4・Thermocouple group. Figure 1 Figure 2 Figure 3 is the slope d M5 figure

Claims (1)

[Claims] 1. A link with a tail at the tip is attached in a cantilever shape to the head that touches the object to be measured, and the link and tail serve as a spring and mass that constitute a vibrator for detecting vibrations. thermally isolated from the outside,
A bearing characterized in that a thermocouple group that measures the temperature difference between the head and tail and simultaneously functions as a thin metal wire strain gauge is attached to the surface of the link, and a part of the thermocouple group can be used for temperature detection. Composite sensor for failure detection.