JPH0523699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an abnormality inspection device for a rotating machine.

(Prior art) Conventionally, in this type of abnormality inspection equipment, frequency analysis is performed by changing the rotation speed of each rotating machine as a product to be inspected in stages, and based on the result of this frequency analysis, each rotating machine is There is a system that detects frequency components corresponding to abnormal sounds and tests whether there is an abnormality in each rotating machine.

(Problems to be Solved by the Invention) However, in such a configuration, the above-mentioned change in the rotational speed is made constant over multiple stages, which makes the inspection complicated and time-consuming. To deal with this, a frequency component corresponding to the abnormal sound generated from the rotating machine is extracted using a filter while the rotational speed of the rotating machine is continuously changed, and the peak value, impulse value, and
It is also conceivable to test the loudness of the abnormal sound based on the average value or the like. However, since the sound pressure level of the abnormal sound changes as the rotation speed changes, there is a problem in that the detection sensitivity for the abnormal sound of the rotating machine is poor, leading to a decrease in detection accuracy.

SUMMARY OF THE INVENTION Therefore, in order to cope with the above-mentioned problems, the present invention provides an abnormality inspection device that can accurately and quickly test whether or not there is an abnormality in a rotating machine.

(Means for solving the problem) In solving the problem, the configuration of the present invention is as follows:
As illustrated in FIG. 1, a first detection means 2 detects the rotation speed or a physical quantity related thereto as a first detection symbol when the rotating machine 1 is driven to change its rotation speed; , a second detection means 3 that detects the sound pressure or mechanical vibration generated from the rotating machine 1 as a second detection signal, and a relationship between these two values according to changes in each value of the first and second detection signals. a first determining means 4 for determining a regression line representing the regression line; a second determining means 5 for determining a reference line parallel to the regression line based on the regression line; a third determining means 6 for determining a corresponding area and determining a range of change in the value of the first detection signal specified by this area and the reference line, and when the determined area is not within a predetermined allowable area; Alternatively, a determining means 7 is provided which determines that there is an abnormality in the rotating machine 1 when the determined change range is not within a predetermined allowable range.

(Function) By configuring the present invention in this way, when the rotation speed of the rotating machine 1 is changed, the first determining means 4 detects the first and second signals from the first and second detecting means 2 and 3. The second determining means 5 determines a reference line based on the regression line, and the third determining means 6 determines the reference line and the first
and determining the area and the change width according to each value of the second detection signal, and the determining means 7 determines that when the determined area is not within the determined allowable area, or the determined change width is within the predetermined allowable width. It is determined that there is an abnormality in the rotating machine 1 only when it is not within the range.

(Effect) As described above, by effectively utilizing the regression line determined by the first determining means 4, the relationship between the reference line based on this regression line and each value of the first and second detection signals is determine the area and the change width,
Based on one or the other of these two determination results, the rotating machine 1
Therefore, the presence or absence of an abnormality in the rotating machine 1 can be detected at high speed and accurately based on both the area and the width of change, which correspond to the magnitude of the abnormality in the rotating machine 1.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an example in which the abnormality inspection device according to the present invention is applied to an alternator G for a vehicle.

This abnormality inspection device has a microphone 10 and a rotation speed sensor 20.
receives the rotation sound generated from the alternator G as the alternator G rotates, and generates a rotation sound signal. The rotation speed sensor 20 detects the rotation speed N of the alternator G and generates a rotation speed signal at a frequency proportional to this detection result. Note that the alternator G is driven by a drive device D.

The amplifier 30 amplifies the rotational sound signal from the microphone 10 and generates it as an amplified signal. The filter 40 extracts a frequency component corresponding to the abnormal rotation sound of the alternator G from the amplified signal of the amplifier 30 and generates it as a filter signal. Effective value conversion circuit 5
0 is generated as an effective value signal by converting the level of the filter signal from the filter 40 into an effective value. The logarithmic conversion circuit 60 logarithmically converts the level of the effective value signal from the effective value conversion circuit 50 into a sound pressure Ls.
Generates Ls as a sound pressure signal. A-D converter 7
0 digitally converts the level of the sound pressure signal from the logarithmic conversion circuit 60 and generates it as a sound pressure digital signal.

The amplifier 80 amplifies the rotational speed signal from the rotational speed sensor 20 and generates an amplified signal. F-V converter 9
0 converts the frequency of the amplified signal from the amplifier 80 into a voltage proportional to the frequency and generates it as a rotation speed voltage signal. The AD converter 100 digitally converts the rotational speed voltage signal from the F-V converter 90 and generates a rotational speed digital signal. The microcomputer 110 executes a computer program based on the outputs from both the A-D converters 70 and 100 according to the flowchart shown in FIG. Performs the necessary calculation processing. However, the above computer program is stored in the ROM of the microcomputer 110 in advance.

In this embodiment configured as described above, when inspecting the alternator G for abnormality, the rotation speed N of the alternator G is changed over time t as shown in FIG.
It is assumed that the alternator G is driven by the drive device D so that the change linearly changes as the time progresses.
When the device of the present invention is operated in such a state, the microphone 10 generates the rotation sound generated from the alternator G as a rotation sound signal, and the rotation speed sensor 20 generates the rotation speed N of the alternator G as a rotation speed signal. .

Next, the amplifier 30 amplifies the rotational sound signal from the microphone 10 and generates a signal, which is passed through the filter 40.
extracts the frequency component corresponding to the abnormal rotation sound of alternator G from the amplified signal and generates it as a filter signal, the effective value conversion circuit 50 converts the filter signal into an effective value signal, and the logarithmic conversion circuit 60 converts the same effective value signal. The level of Ls is logarithmically converted into a sound pressure Ls and this is generated as a sound pressure signal, and the A/D converter 70 converts the sound pressure signal into a sound pressure digital signal. Further, the amplifier 80 generates the rotation speed signal from the rotation speed sensor 20 as an amplified signal, and the F-V converter 90
converts the amplified signal from the amplifier 80 into a rotation speed voltage signal, and the AD converter 100 converts the rotation speed voltage signal into a rotation speed digital signal.

In the above operating process, as the rotational speed N increases linearly with the passage of time t as shown in Fig. 4, the sound pressure Ls corresponding to the abnormal rotation noise generated from the alternator G increases as shown in Fig. 5. As shown by curve 1, it is assumed that the rotational speed N changes as the rotational speed N changes. As the apparatus of the present invention operates, the microcomputer 110 starts executing the computer program at step 200a according to the flowchart shown in FIG.
Sound pressure digital signal from converter 70 and A-D
A rotational speed digital signal from the converter 100 is input as time t elapses. In such a case, the rotation speed N is temporarily stored in the microcomputer 110 so as to increase linearly with the passage of time t, and the sound pressure Ls is stored as a curve l as the rotation speed N linearly increases. It is temporarily stored in the microcomputer 110 as specified by.

When the arithmetic processing in step 210 is thus completed, the microcomputer 110 creates a regression line P in step 220 as follows. Now, in FIG. 5, it is assumed that the sound pressure Ls is represented by the Y coordinate, the rotational speed N is represented by the X coordinate, and the regression line P is represented by Y=aX+b. Therefore, as shown in Figure 5, if the coordinates on the curve l are (Xi, Yi), then S(XX)=ΣXi ² −n() ² …… (3) S(YY)=ΣYi ² −n() ² …… (4) S(XY)=ΣXiYi−n…… (5) a=S (XY)/S(XX)...(6) b=-a...(7) holds true. Therefore, by taking n pieces of (Xi, Yi) on the curve l and calculating from both equations (1) and (2) as well as from equations (3) to (7), the regression line P is obtained as shown in Figure 5. You can get it as follows.

Thereafter, in step 230, the microcomputer 110 determines a reference line Q by shifting the regression line P upward in FIG. 5 by α dB (for example, 2 dB) in order to improve the S/N ratio. In such case,
Each shaded area in FIG. 5 is a region of sound pressure Ls corresponding to abnormal rotation noise from alternator G. computer program steps
Proceeding to 240, the microcomputer 110
In the following manner, each of the hatched areas is calculated as the abnormal sound area S=S ₁ or S=S ₂ , and each of the hatched areas is calculated as each rotation speed width ΔN ₁ or ΔN ₂ specified by the reference line Q. Calculate. That is, ΔYi=Yi−(aXi+b)...(8) ΔXi=X _i+1 −Xi...Based on both equations (9) and equations (6) and (7), ΔYi and ΔXi when ΔYi>0 By calculating S=ΣΔXi·ΔYi (10) ΔN=ΣΔXi (11), S=S ₁ or S ₂ and ΔN=ΔN ₁ or ΔN ₂ are obtained. However, equations (1) to (11) are stored in advance in the ROM of the microcomputer 110. Note that in the range of rotation speeds excluding ΔN ₁ and ΔN ₂ , in step 240, ΔN=0, S=
It is calculated as 0.

As described above, when the abnormal sound area S and the rotation speed width ΔN are calculated in relation to the reference line Q according to the increase in the rotation speed N of the alternator G, the step
If S=S ₁ <S ₀ and S=S ₂ <S ₀ in 240, then
The microcomputer 110 determines "NO" at step 250. Then, even if ΔN=ΔN ₁ <ΔN ₀ in step 240, ΔN=ΔN ₂ >ΔN ₀
If so, the microcomputer 110 determines "YES" in step 260, and in step 270, an abnormality display necessary for flashing the indicator lamp 130 indicating that the abnormal sound from the alternator G exceeds the permissible limit is displayed. A signal is generated for a predetermined period of time. On the other hand, S=S ₂ in step 240
If S _{is 0} or more, the microcomputer 110 determines "YES" in step 250, and proceeds to step 270.
An abnormality display signal is generated for a predetermined period of time.
As described above, when the abnormality display signal is generated from step 270, the drive circuit 120 causes the display lamp 130 to flash for the predetermined period of time. however,
The code S ₀ shown in step 250 is the alternator G
(hereinafter referred to as "allowable abnormal area")
On the other hand, the code ΔNo shown in step ₂₆₀ represents the allowable range of the rotational speed width ΔN that defines the abnormal sound area ΔS (hereinafter referred to as the allowable rotational speed width ΔNo).
represent. Note that So and ΔNo are stored in the ROM of the microcomputer 110 in advance. Also,
In the calculation results performed in step 240 as described above, S ₁ <S ₀ , S ₂ <S ₀ , ΔN ₁ <ΔN ₀ and ΔN ₂
<If ΔNo holds true, the microcomputer 110 sequentially outputs "NO" at each step 250 and 260.
In step 280, a normal display signal necessary for continuous lighting of the display lamp 130 indicating that no abnormal noise is generated from the alternator G is generated, and in response to this, the drive circuit 120 turns on the display lamp 130. Lights up continuously for a predetermined period of time.

As explained above, based on the calculation results at each step 220 to 240 regarding the alternator G, if the determination at either step 250 or 260 becomes "YES", the indicator lamp 130 will turn to the predetermined position. Since the light is flashing for a certain period of time, it can be recognized that the alternator G is making abnormal noise. On the other hand, if the determinations in both steps 250 and 260 are both "NO",
Since the indicator lamp 130 is lit continuously for the predetermined period of time, it can be recognized that the alternator G does not generate any abnormal noise. In such a case, curve l (see Figure 5)
In relation to the shape of and the reference line Q, S≧S ₀ and ΔN
Since the occurrence of abnormal noise in the alternator G is determined in response to the establishment of at least one of ≧ΔN ₀ , it is possible to ensure an improvement in inspection accuracy. Furthermore, since the measurement is performed after continuously changing the rotational speed, the inspection speed can be shortened.

Incidentally, when the other two alternators were inspected using the apparatus of the present invention in the same manner as alternator G, one of the alternators was found to be of good quality in terms of abnormal noise, as shown in FIG. Also,
The other alternator is as shown in Figure 7.
We were able to inspect the abnormal noise and find that it was of poor quality.

In carrying out the present invention, in cases where it is difficult to detect abnormal sounds of the alternator G due to the influence of background noise, or where poor quality of the alternator G is clearly identified in the form of mechanical vibrations of the alternator, A vibration sensor may be used instead of the microphone 10, and the vibration detection results from this vibration sensor may be used to conduct the inspection in the same manner as described above, or the detection results from the microphone 10 and the vibration sensor may be combined. It may also be carried out.

Furthermore, in carrying out the present invention, if the rotational speed of the alternator G increases or decreases linearly as shown in FIG. 4, the rotational speed N
Instead, even if the determination in step 260 is made based on the rotation time of the alternator G, substantially the same effect as in the embodiment described above can be achieved. In addition, if a linear change in the rotational speed as shown in Fig. 4 cannot be expected, the sound pressure Ls can be sampled at low rotational speed intervals based on the detected rotational speed.
Substantially the same effects as in the previous embodiment can be achieved.

Further, in carrying out the present invention, the present invention is of course not limited to the alternator G, and can of course be applied to abnormality inspections of various rotating machines such as various generators and electric motors.

In addition, in carrying out the present invention, there are steps to be taken.
The sum of S (S ₁ + S ₂ ) and the sum of ΔN (ΔN ₁ +ΔN ₂ ) at 240 is calculated at each step 250 and 260.
The determination may be made by comparing with S ₀ and ΔN ₀ .

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the structure of the invention described in the claims, FIG. 2 is a block diagram showing an embodiment of the invention, and FIG. 3 is a flowchart showing the operation of the microcomputer shown in FIG. Fig. 4 is an explanatory diagram of the driving state of the alternator, Fig. 5 is an explanatory diagram for creating a regression line and a reference line, and Figs. 6 and 7 are explanatory diagrams of the test results of other alternators. . Explanation of symbols, G... Alternator, 10...
Microphone, 20... Rotation speed sensor, 110...
...Microcomputer.

Claims (1)

[Claims] 1. A first detection symbol that detects the rotation speed or a physical quantity related thereto in a state in which the rotating machine is driven to change its rotation speed.
a detection means; a second detection means for detecting sound pressure or mechanical vibration generated from the rotating machine as a second detection signal; a first determining means for determining a regression line representing the relationship; a second determining means for determining a reference line parallel to the regression line based on the regression line; and a second determining means corresponding to an area where the value of the second detection signal exceeds the reference line. a third determining means for determining an area to be detected and a range of change in the value of the first detection signal specified by this area and the reference line; An abnormality inspection device for a rotating machine, comprising a determining means for determining that there is an abnormality in the rotating machine when the determined change range is not within a predetermined allowable range.