JPS62151621A - Device for detecting abnormality in rolling bearing - Google Patents

Abstract

PURPOSE:To securely detect the damage of a rolling bearing by outputting the compared result of an acceleration vibration level when a rotation speed agrees with a reference rotation speed. CONSTITUTION:At the point of time when the rotation speed (c) of a rotary shaft 2 agrees with a reference rotation speed Rs, and only when a vibration level (b) resulting from the damage of a rolling bearing 3 becomes above the allowable level As in the reference rotation speed Rs, an AND circuit 12 is satisfied, sending out a warning signal (g) from a latch circuit 17. Accordingly, merely by setting only the allowable level As in an allowable-level setting device 11, a damage 19 more than allowable level that has developed on the rolling bearing 3 can be securely grasped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rolling bearing abnormality detection device for detecting damage to a rolling bearing that supports a rotating shaft of a rotating device.

[Prior Art] In general, as a means of detecting abnormal conditions such as damage to rolling bearings that support the rotating shafts of various rotating equipment, including electric motors and generators, an acceleration detector is attached to the outer surface of the rolling bearing. The rolling bearing is rotated and the acceleration vibration level of the rolling bearing detected by the acceleration detector is measured. It is known from experience that the acceleration vibration level caused by damage to a rolling bearing increases approximately in proportion to the square of the rotational speed of the rotating shaft supported by the rolling bearing. If a predetermined tolerance level is exceeded, it is determined that an abnormal situation such as damage has occurred in this rolling bearing.

In actual measurements, the acceleration signal detected by the acceleration detector attached to the outer surface of the rolling bearing includes not only the vibration frequency caused by this rolling bearing damage, but also
An acceleration signal having a frequency corresponding to the rotation speed is superimposed due to unbalance around the rotation axis of the rotating part of the rotating equipment itself.

Therefore, the first order of the rotational frequency corresponding to the above rotational speed,
A bandpass filter or a bypass filter is used to remove secondary, . . . , frequency components.

[Problems to be Solved by the Invention] However, as mentioned above, the acceleration vibration level due to damage to rolling bearings changes approximately in proportion to the square of the rotational speed, so the permissible level also changes depending on the rotational speed. There is a need. On the other hand, rotating equipment generally does not operate at a constant speed, but instead repeatedly accelerates and decelerates, and is operated at various rotational speeds. Therefore, the tolerance level for detecting damage to rolling bearings installed in such rotating equipment also needs to be set to a value corresponding to the square of the rotational speed.

However, setting each tolerance level for each rotational speed in proportion to the square of the rotational speed requires a very complicated circuit.

Also, in order to eliminate this inconvenience, certain 2! It is conceivable to set a permissible level at a semi-rotational speed in advance, and to sound a warning buzzer or turn on a warning lamp when the acceleration vibration level exceeds this permissible level. If the temperature is increased above this level, a problem arises in which a warning buzzer sounds or a warning lamp lights up even though the actual damage is below the allowable level.

The present invention has been made based on such circumstances, and its purpose is to output a comparison result of acceleration vibration level only when the rotation speed matches a reference rotation speed set as an allowable level. Therefore, it is an object of the present invention to provide a rolling bearing abnormality detection device that has a simple configuration and can reliably detect damage to a rolling bearing.

[Means for Solving the Problems] In the rolling bearing abnormality detection device of the present invention, an acceleration signal detected by an acceleration detector that detects vibration acceleration of a rolling bearing that supports a rotating shaft of a rotating equipment is provided. Among them, only the vibration level of the vibration frequency component caused by damage to the rolling bearing is passed through the filter, and the tolerance level setting device determines the tolerance level of the vibration frequency component caused by the damage at a predetermined thread rotation speed of the rotating shaft. A comparator compares the vibration level output from the filter with an allowable level, and outputs a level over signal when the vibration level is higher than the allowable level. In addition, when the rotational speed of the rotating shaft of the rotating equipment detected by the rotational speed detection device matches the reference rotational speed, a speed matching signal is output from the matching circuit, and this matching signal and the level override output from the comparator are output. An AND signal with the signal is calculated by an AND circuit, and a latch circuit latches the AND signal output from the logic circuit to output a warning signal.

[Operation] With the rolling bearing abnormality detection device configured as described above, the acceleration signal of the rolling bearing detected by the acceleration detector is filtered to remove only the vibration level of the frequency component caused by damage to the rolling bearing. taken out and compared in a comparator with an acceptable level of damage at a reference rotational speed;
If this permissible level is exceeded, a level over signal is sent to the AND circuit at the next stage. On the other hand, a coincidence signal to which the rotational speed of the rotating shaft is inputted from the rotational speed detection device is sent to the AND circuit only when the rotational speed matches the base thread rotational speed. Therefore, the latch circuit to which the AND signal is input from the AND circuit outputs a warning signal when the level over signal and the match signal match.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a rolling bearing abnormality detection device according to an embodiment. In the figure, reference numeral 1 denotes a rotating device including, for example, a motor 1 and a generator, and a rotating shaft 2 of the rotating device 1 is supported by a rolling bearing 3 in a casing of the rotating device 1. This rolling bearing 3, as shown in FIGS. 2(a) and (b),
An annular outer ring 4 fixed to the body of the rotating device 1, an inner ring 5 fixed to the rotating shaft 2, and a plurality of rolling elements 6 inserted between the outer ring 4 and the inner ring 5. It is configured.

An acceleration detector 7 for detecting acceleration vibrations of the rolling bearing 3 is freely attached to the outer surface of the rolling bearing 3, and the acceleration signal a detected by the acceleration detector 7 is amplified by an amplifier 8. After that, it is manually input to the band pass filter 9.

The pass frequency band of the band-pass filter 9 is set to include the frequency component of acceleration vibration that occurs when the inner ring 5 of the rolling bearing 3 is damaged. Normally, the frequency of acceleration vibration due to damage to the inner ring 5 is determined by the dimensions and shape of the rolling bearing 3, and is a high value that does not depend on the rotational speed of the rotating shaft 2. Therefore, in the bandpass filter 9 of the embodiment, the pass frequency band is 10K.
The frequency is set between Hz and 40KHz. Note that this bandpass filter 9 converts the acceleration signal that has passed through the above frequency band into a DC vibration level b and outputs it.

The vibration level b output from the bandpass filter 9 is input to (10) input terminals of the comparator 10. To the (-) input terminals of this comparator 10, the allowable level AS output from the allowable level setter 11 is input manually. This allowable level setter 11 is constructed of a constant voltage circuit as shown in the figure, and generates an acceleration signal caused by damage to the rolling bearing 3 when the rotational speed of the rotating device 1 reaches a preset reference rotational speed R5. The permissible level AS of direct current corresponding to (-) is sent to the (-) input terminals of the comparator 10.

When the vibration level b of the bandpass filter 9 inputted to the (+) input terminals exceeds the permissible level AS inputted to the (=) input terminals, the comparator 10 outputs an H level level over signal e from the output terminal. is sent to one input terminal of the AND circuit 12.

On the other hand, a rotation pulse detector 13 for detecting the rotation speed of the rotation shaft 2 is attached to the rotating device 1, and a pulse signal detected by the rotation pulse detector 13 is counted by a counter 14 for a predetermined period of time. , rotational speed C to one input terminal of the matching circuit 15. therefore,
The rotation pulse detector 13 and the counter 14 constitute a speed detection device. The reference rotation speed R5 is input from the rotation speed setter 16 to the other input terminal of the matching circuit 15. Then, the rotational speed C input from the counter 14
is the rotational speed R8 manually inputted from the rotational speed setting device 16.
Only when they match, an H level match signal d is sent to the other input terminal of the AND circuit 12.

The AND signal f output from the AND circuit 12 is input to the latch circuit 17. This latch circuit 17 receives the input H
A warning signal g is sent to the output terminal 18 to which a warning buzzer, warning lamp, etc. are connected while latching the AND signal f of the level.
Output.

The operation of the rolling bearing abnormality detection device configured as described above will be explained with reference to FIGS. 3 and 4. For example, if slight damage 19 occurs in the inner ring 5 of the rolling bearing 3, as shown in FIG. A high frequency vibration waveform 20 caused by the damage 19 is superimposed. This high frequency vibration 20 is an impact vibration generated when the rolling elements 6 pass through a damaged area 19 of the inner ring 5, and is actually a vibration modulated by the natural frequency of the rolling bearing 3. Normally, the natural frequency of the rolling bearing 3 is about 10 KHz due to its structure, and the bandpass filter 9
is set so that only the vibration component of approximately 10 Hz passes through. By passing through this band-pass filter 9, the vibration waveform 20 caused by the damage 19 becomes the DC vibration level b shown in FIG.

Then, when the rotating device 1 starts rotating at time 1o and its rotational speed C increases apart from the linear characteristic shown in FIG. 4, as the rotational speed C increases, the bandpass filter 9 outputs The vibration level b input to the (+) input terminals of the comparator 10 increases in proportion to the square of the rotational speed C, as described above. When the rotational speed C matches the reference rotational speed R6 set in the rotational speed setter 16 at time t1, the matching circuit 15 outputs a pulsed matching signal d. Note that at this point, the vibration level b manually applied to the comparator 10 has not reached the allowable level AS, so the output signal of the comparator 10 remains at the L level.

Then, when the rotation speed C of the rotating device 1 further increases and the vibration level b exceeds the allowable level AS at time t2, the comparator 10 sends a level over signal e of H level to the AND circuit 12. .

When the rotational speed C of the rotating device 1 decreases, the vibration level b also decreases accordingly. Then, at time t3, when the vibration level b falls below the allowable level As, the level-over signal e output from the comparator 10 returns to the L level. The rotational speed C further decreases and the reference rotation speed RS
A pulse-like coincidence signal d is output at time t4 when it crosses . In this way, when the rotational speed C crosses the reference rotational speed R5, the AND circuit 12 is not established unless the vibration level b exceeds the allowable level AS, so a warning signal is sent from the latch circuit 17 to the output terminal 18. g is never sent.

For example, if the vibration level b exceeds the allowable level AS at time t5, and the rotational speed C exceeds the reference speed R5 at time t6 when the vibration level b does not fall below the allowable level As, that is, when the speed increases match signal d
If the level over signal e is output earlier, the H level over level signal e and the coincidence signal e are input to the AND circuit 12. Therefore, this AND circuit 12
is established, and an H-level AND signal f is sent to the latch circuit 17. Once the logical product signal f at H level is input, the latch circuit 17 latches the logical product signal f and sends out a warning signal g to the output terminal 18. As a result, a warning buzzer connected to the output terminal 18 sounds or a warning lamp lights up.

Once the AND signal f at H level is latched by the latch circuit 17, the match signal d of the match circuit 15 returns to L level, and even if the established state of the AND circuit 12 is canceled,
The latch state will not be released unless a reset signal is input to the latch circuit 17 from the outside. Therefore, the warning buzzer and warning lamp will not stop unless the warning buzzer and warning lamp are released.

With the rolling bearing abnormality detection device configured in this way, when the rotational speed C of the rotating shaft 2 matches the reference rotational speed R5, the vibration level b caused by the damage 19 of the rolling bearing 3 reaches the reference rotational speed. Tolerance level AS in RS
Only when it exceeds , the AND circuit 12 is established and the latch circuit 17 sends out the warning signal g.

As mentioned above, the vibration level b of the acceleration vibration caused by the damage 19 to the rolling bearing 3 is approximately 2 of the rotational speed C.
Since it changes in proportion to the product of You can understand this with certainty.

Also, since only one point is required for the tolerance level As to be set,
The entire device can be simplified and manufacturing costs can be reduced.

[Effects of the Invention] As described above, according to the present invention, the comparison result of the acceleration vibration level is output only when the rotational speed matches the reference rotational speed in which the permissible level is set. Therefore, damage to the rolling bearing can be detected reliably with a simple configuration, and it is possible to reduce the manufacturing cost and improve the reliability of the entire device.

[Brief explanation of drawings]

The figures show a rolling bearing sound emitting device according to an embodiment of the present invention, and FIG. 1 is a schematic block diagram showing a 14-structure structure, FIG. 2 (a) is a front view showing a rolling bearing, Same figure (
b) is a folded view showing the same rolling bearing, FIG. 3 is a waveform diagram showing an acceleration signal detected by an acceleration detector, and FIG. 4 is a time chart showing the operation. DESCRIPTION OF SYMBOLS 1... Rotating equipment, 2... Rotating shaft, 3... Rolling bearing, 4... Outer ring, 5... Inner ring, 6... Rolling element,
7... Acceleration detector, 8... Amplifier, 9... Bandpass filter, 10... Comparator, 11... Tolerance level setter, 12... AND circuit, 13... - Rotation pulse detector, 14... Counter, 15... Matching circuit, 16... Rotation speed setter, 17... Latch circuit,
18...Output terminal, 19...Damage, 20...Vibration waveform, As...Tolerance level, R5...Reference rotation speed. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (1)

[Claims] an acceleration detector that detects the acceleration vibration level of a rolling bearing that supports a rotating shaft of a rotating device; vibration of a vibration frequency component caused by damage to the rolling bearing of the acceleration vibration level signal detected by the acceleration detector; a filter that allows only the vibration level to pass through; an allowable level setter that outputs an allowable level of the vibration frequency component caused by the damage at a predetermined reference rotational speed of the rotating shaft; and the vibration level output from the filter; a comparator that compares the vibration level with the permissible level and outputs a level over signal when the vibration level is higher than the permissible level; a rotation speed detection device that detects the rotation speed of the rotation shaft; a matching circuit that outputs a speed matching signal when the detected rotational speed matches the reference rotational speed; an AND signal of the matching signal output from the matching circuit and the level over signal output from the comparator; A rolling bearing abnormality detection device comprising: an AND circuit that outputs an output; and a latch circuit that latches the AND signal and outputs a warning signal.