JPS6236525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration detection device that detects shaft vibration of a rotating body such as a generator, a turbine, or a motor.

A conventional device of this type is shown in FIG. In the figure, 1 is a cross-sectional view of the shaft of the rotating body (the arrow indicates the direction of rotation), 2 is the case of the rotating body, 3 is a vibration detector with pick-ups 4 and 5 housed inside, 5a, 5b is a component of the pickup 5, 6a and 6b are high frequency oscillators, 7 is an adder, 8
a, 8b, and 8c represent comparators, and Pa, Pb, and Pc represent determination outputs of the comparators 8a, 8b, and 8c, respectively.

Next, the operation will be explained. The high frequency wave emitted by the oscillator 6b is supplied to the pickup 4 to obtain a voltage proportional to the gap between the pickup 4 and the rotating body 1, which is input to the comparator 8c and the adder 7.
When vibration occurs in the rotating body 1 and the gap between the rotating body 1 and the pick-up 4 becomes smaller (larger), the eddy current in the pick-up 4 increases (decreases), and the eddy current from the oscillator 6b to the comparator 8c increases. The output to the adder 7 becomes larger (smaller). The comparator 8c detects an increment (decrease) from a predetermined initial value, and if this value is greater than a certain value, a signal is output to the output Pc indicating that there is vibration. This signal Pc is determined by detecting the relative vibration between the case 2 and the rotating body 1 because the pick-up 4 is attached to the rotating body case 2, and if there is no vibration in the case 2. then the signal
This means that Pc correctly detects the vibrations of the pick-up 4 and the rotating body 1, that is, the rotating body 1. If the vibration in case 2 cannot be ignored, it is necessary to remove the vibration in case 2 from the signal Pc, and the pick-up 5 takes measures for this. The pick-up 5 has an inertial structure. That is, the component 5a has inertia and does not move even if the case 2 vibrates. On the other hand, since the element 5b is vibrating together with the case 2, the pick-up 5 is detecting the vibration between the elements 5a and 5b, which means that the vibration of the case 2 is being detected. Therefore, the output Pa of the comparator 8a operates to output when the vibration of the case 2 exceeds a certain value. Next, the oscillator 6a added to the adder 7,
The value from 6b is now added in a subtractive manner, i.e. the signal from 6a is removed from the signal from 6b, and the output of adder 7 is the same as that of pick-up 4 and rotation regardless of the presence or absence of vibration in case 2. This means detecting vibrations between the bodies 1. Therefore, comparator 8b
The output Pb is used to determine the magnitude of vibration between the pick-up 4 and the rotating body 1, and is used to determine the vibration of the rotating body. These output signals Pa, Pb, and Pc are vibrations above a certain level, and are used as a signal to stop a rotating body or to generate an alarm for large vibrations.

The conventional devices described above have already been widely put into practical use, and there are no problems under normal circumstances. However, it has the following drawbacks.

(1) When there is a scratch on the shaft of the rotating body, the distance (gap) between the rotating body 1 and the pick-up 4 appears to change, making it appear as if vibration has occurred. This becomes a problem as the accuracy of vibration detection increases, and there is a risk of false detection.

(2) Increasing the precision of machining the shaft of the rotating body 1 increases the machining cost, making the vibration detection system expensive.

(3) Since a defect is known only when the vibration value exceeds a certain level, it is not possible to know about changes over time, which is a requirement for maintenance.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by computer processing the information obtained from the vibration pickup,
The purpose of the present invention is to provide a vibration detection device that is inexpensive, highly accurate, and satisfies requirements beyond maintenance.

The vibration detection device according to the present invention includes a pickup that outputs each output in response to each vibration of a rotating body and a case of the rotating body, and a plurality of reference values of a time-varying pattern corresponding to each output of the pickup. a setting device for setting in advance a plurality of different operating state patterns for the rotating body and the case of the rotating body; and a determination device that determines a failure status of the rotating body based on comparison results regarding a rotating body of the comparing device and a plurality of different operating state patterns in the case of the rotating body, the determining device The vibration of the rotating body is detected based on the determination result.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an embodiment of this invention, in which 9
a, 9b, 9c are setting devices 10a, 1 for presetting the standard of the time change pattern of vibration output;
0b, 10c are comparison devices that compare the outputs of the setting devices 9a, 9b, 9c with the outputs of the transmitter 6a, adder 7, and transmitter 6b, and 12 are the respective comparison devices 10a, 1.
A determination device which determines the failure status of the rotating body 1 according to the determinations of 0b and 10c and issues an alarm or a command to stop the rotating body 1; 13 is a computer; 10a, 10b, 1
0c is built in, P is the output signal.
Note that the same reference numerals in FIG. 2 indicate the same or corresponding parts as in FIG. 1.

Next, the operation shown in FIG. 2 will be explained. The components other than the computer 13 in FIG. 2 are the same as in FIG. 1. Pick
The magnitude of the vibration detected by ups 5 and 4 is determined by the setting device 9a, the comparing device 10a and the setting device 9, respectively.
c, applied to the comparator 10c. Also pick
The magnitudes of the vibrations detected by ups 5 and 4 are calculated by an adder 7 and the difference is output, and the difference output is given to a setting device 9b and a comparator 10b. With this connection, the vibrations detected by the pick-up 4 are determined by the comparator 10c. Comparator 10c
compares the setting pattern of the setting device 9c, which is preset from the vibration generation pattern, with the currently occurring vibration generation pattern, and provides a signal of the difference to the determination device 12. The setting pattern of the setting device 9c is set according to the state of the rotating body 1, or is set by storing the vibration pattern at the time of manufacture (for example, during a trial run). In this way, even if the rotating body is scratched and the gap between the pickup 4 and the rotating body 1 changes due to the scratch, if there is no vibration, the vibration pattern will not change and the comparator 10c will determine that there is no vibration. I will do it. The output of the comparator 10c gives a difference from the time of manufacture, so if this value is monitored, changes over time can be known. The output of the comparator 10c is used by the determination device 12 to issue an alarm when the value exceeds a certain value, to stop the rotating body 1, and to store data in a recorder. The vibration output detected by the pick-up 5 is processed by the setting device 9a and the comparator 10a as in the case of the pick-up 4, and the output of the comparator 10c is the difference between the manufacturing time and the current value (pattern difference). is generated as output. The difference between pick-ups 4 and 5 is derived by an adder 7, and the value is similarly processed by a setting device 9c and a comparator 10b. Fig. 2 also shows that the vibration outputs of the pick-ups 4 and 5 are directly introduced into the determination device 12, but this is the same function as the pick-up in Fig. 1.
This indicates that the detected value of UP is processed as vibration information of the rotating body 1, and if necessary, the comparison device 1
This indicates that it can be used in addition to 0a, 10b, and 10c. FIG. 2 13 shows a computer, and the comparison device, setting and comparison of time change patterns, etc. can be easily realized. Further, the computer may be a small device such as a μ-P (microprocessor) and may be used exclusively for vibration detection, or may be shared with other devices.

In the above description of the embodiment, it was explained that the setting device is used to set the vibration pattern during manufacturing.
It is also possible to install a plurality of similar setting devices and comparison devices to provide a plurality of setting patterns at different times. In this way, fine-grained vibration detection is possible by providing separate setting patterns for different operating conditions (for example, immediately after the rotating body is started, and during rated operation, etc.) and performing selective operation. Although the above description has been made using a non-contact type pickup that uses high frequency, other methods such as a contact type may also be used. Also, in the explanation of Fig. 2, the case where pick ups 4 and 5 are applied together is shown.
In practical use, it may be possible to omit the adder 7 that knows the difference, omit the pick-up of one of them, etc.

As described above, since the present invention is configured to detect vibrations based on changes, vibrations can be detected correctly even if there are scratches, etc., and therefore machining of the shaft surface of a rotating body can be carried out easily. Since it does not need to be rough, a vibration detection system can be made at low cost, with high accuracy, and by monitoring the magnitude of the change, it is possible to know the change over time.

[Brief explanation of the drawing]

FIG. 1 shows a conventional vibration detection device, and FIG. 2 is a configuration diagram showing an embodiment of the vibration detection device according to the present invention. In the figure, 1 is a rotating body, 2 is a case of the rotating body 1, 3 is a vibration detection device that houses pick-ups 4 and 5, 6a and 6b are high frequency oscillators, 7 is an adder, and 9a, 9b, and 9c are Setting device, 10a, 10
b and 10c are comparison devices, and 12 is a determination device.
Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A pickup that outputs each output in response to each vibration of the rotating body and the case of the rotating body, and a plurality of standard values of the time-varying pattern corresponding to each output of the pickup, of the rotating body and the rotating body. a setting device that sets in advance a plurality of different operating state patterns for each case, and a comparison device that compares the plurality of different operating state patterns for the rotating body and the case of the rotating body set by the setting device with the output of the pickup. and a determination device that determines the failure status of the rotary body based on the comparison results regarding the rotary body and a plurality of different operating state patterns in the case of the rotary body of the comparison device, A vibration detection device characterized in that it is configured to detect vibrations of.