JP3221202B2 - Dynamic balance testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic balance testing machine suitable for measuring the unbalance of a rotating specimen.
More particularly, the present invention relates to a dynamic balance tester capable of calculating an unbalance amount of a test specimen whose shaft is bent during rotation.

[0002]

2. Description of the Related Art In a well-known dynamic balance tester, a pair of shafts of an elongated cylindrical specimen such as a motor rotor is supported by a holder, and vibration or vibration of the holder when the specimen is driven to rotate by a belt is measured. Measure the centrifugal force with the pickup. An output signal from the pickup is input to an arithmetic circuit, and the unbalance amount and the unbalance position of the left and right shaft portions 2 are calculated and displayed. For example, when correcting imbalance manually, if the rotor is bent, an ordinary testing machine displays the weight and position of the weight to be added as if there is no deflection, The weight and position of the weight to be added are empirically determined, and a correction weight is added to a predetermined position of the specimen.

[0003]

Conventionally, a specimen is regarded as a rigid body, that is, assuming that the axis does not bend during rotation, and to correct the left and right based on a measurement signal from a pair of left and right pickups. Since the predetermined unbalance amount between the two surfaces is calculated and displayed, there is the following problem. As shown in FIG. 6, a specimen in which shaft portions 52 protruding from both ends of a specimen main body 51 which is a rotating body are connected via an elastic coupling 53 such as rubber has a completely unbalanced structure. Even if corrected, when the shaft portion 52 is supported on the holder and rotated, the shaft center is bent and rotated as shown in FIG. In the case where there is an imbalance in such a specimen in which the axis rotates while bending, and in the case where there is an imbalance in a rigid specimen in which the axis rotates without bending, the indication is displayed on the display. Even if the imbalance amounts are equal,
The weight of the weight added for correction is different.

FIG. 2 is a diagram in which the horizontal axis represents the weight of the weight added to the center of the specimen and the vertical axis represents the static imbalance. Assuming that the unbalance of the specimen has been corrected to almost zero in advance, if the specimen is a rigid body, the static unbalance amount is also directly proportional to the increase in the weight of the added weight, as indicated by the broken line a. To increase. However, when the specimen elastically deforms as shown in FIG. 7, the weight of the additional weight and the static imbalance amount are not directly proportional, and as shown by the solid line b, compared to the case of the rigid specimen. The amount of static imbalance is large due to the elastic deformation. In other words, the weight of the weight to be added to correct the unbalance amount displayed on the display needs to be smaller in the elastically deformed specimen than in the rigid specimen.

However, the solid line b in FIG. 2 also differs depending on the degree of the elastic deformation, and based on the unbalance amount calculated and displayed on the basis of the rigid specimen,
It is difficult even for an expert to judge the weight of the weight added to the elastically deformed specimen. Therefore, it is necessary to correct the imbalance while controlling the added weight, and there is a problem that workability is poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dynamic balance tester capable of calculating an unbalance amount of a specimen which rotates with its axis of rotation flexing particularly during measurement.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a dynamic balance testing machine capable of calculating the unbalance amount of a specimen rotating with its shaft center bent, and the unbalance amount of a rotationally driven specimen is calculated. Detecting means for detecting a corresponding vibration or centrifugal force, and an unbalance amount for calculating an unbalance amount of the specimen from the vibration or centrifugal force detected by the detecting means, assuming that the specimen does not bend during rotation. Operation means and weights of various sizes are added to the substantially central portion of a rotating dummy specimen whose axis is flexed and the unbalance amount is corrected to substantially zero in advance, and the weight is detected by the detection means at that time. Correspondence calculating means for calculating the correspondence between the unbalance amount calculated by the calculating means based on the detection result and the weight of the added weight, and Correspondence calculated by correspondence relation calculation means Based on the engagement, characterized by comprising a correction means for correcting the unbalance amount calculated by said calculating means. The correspondence between the detection result of the detection means and the weight of the additional weight is determined, and for a specimen whose shaft is bent and rotated, the detection result of the detection means is corrected based on the previously obtained correspondence. Alternatively, the unbalance amount may be obtained.

[0008]

[Action] A dummy specimen whose axis is flexed and rotates with an unbalanced amount corrected to substantially zero in advance is prepared, and weights of various sizes are added to a substantially central portion thereof. The unbalance amount is obtained for each weight by the unbalance calculation means based on the detected result. The correspondence calculating means calculates a correspondence between the weight of the added weight and the calculated unbalance amount, for example. For a specimen whose axis is flexed and rotated at the time of unbalance measurement, the arithmetic means is operated based on the correspondence between the weight of the weight added to the dummy specimen and the unbalance amount detected at that time. The unbalance amount of the specimen is corrected by the correction means. When the correspondence between the detection result of the detection means and the weight of the additional weight is determined, the detection result of the detection means is determined based on the above-described correspondence relation for a specimen whose shaft is bent and rotated. And an unbalance amount is calculated based on the corrected detection result.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing one embodiment of a dynamic balance tester to which the present invention is applied. The shafts 2 and 3 at both ends of the specimen 1 are held on bearings 6 and 7 elastically supported by springs 4 and 5, and the specimen 1 is rotated by a motor 17 via a belt 8. Pickups 9 and 10 for measuring vibration displacement due to imbalance of the test sample 1 are connected to the bearings 6 and 7, respectively, and detection signals from the pickups 9 and 10 are supplied to arithmetic / logic circuits via amplification / filter circuits 11 and 12, respectively. 13 14 is a mark marked on the reference position of the specimen, 15 is a photo sensor arranged opposite to the mark,
The signal of the photo sensor 15 is taken into the arithmetic circuit 13 via the amplifier 16.

The arithmetic circuit 13 includes an arithmetic unit 13a and a storage unit 1
3b and a correction unit 13c. The arithmetic unit 13a is configured to detect the detection signals from the pickups 9 and 10 and the photo sensor 15
The unbalance amount and the unbalance position are calculated based on the reference position signal from the CPU. Here, the unbalance amount and the unbalance position are calculated as a rigid test piece whose axis does not bend during rotation. The storage unit 13b stores correction data as follows.

Prior to the measurement, an elastically deformable type dummy specimen as shown in FIGS. 6 and 7 in which the imbalance has been corrected to almost zero is prepared in advance. The dummy specimen is set on a dynamic balance tester, and a weight is added to the center of the specimen to measure the unbalance amount. The weight x of the additional weight is increased for each predetermined unit, and the unbalance amount is measured for each weight. When the unbalance measurement value based on the detection signal from the left pickup 9 is represented by a vector amount L, and the unbalance measurement value based on the detection signal from the right pickup 10 is represented by a vector amount R, the static unbalance amount S is L + R.
A graph shown by a solid line b in FIG. 2 is obtained in which the weight x of the additional weight is plotted on the horizontal axis and the static imbalance vector amount S is plotted on the vertical axis. The correspondence between the weight x of the additional weight and the static imbalance amount S is stored in the storage unit 13b.

The operation unit 13a represents the curve b as a function of y = f (x) from the data of the curve of the solid line b by a least squares method or a broken line approximation method, and an inverse function f (x) of this function. ^{Find -1} . The solid line c in FIG.
(X) A curve indicated by ^-1 . here,

Assuming that f (x) × f (x) ⁻¹ = 1 (1) is satisfied, the inverse function f (x) ⁻¹ becomes

F (x) ⁻¹ = 1 / f (x) (2) Thus, the operation unit 1
3a represents the solid line c in FIG.

Y = f (x) ⁻¹ = 1 / f (x) (3), and the preparation for measurement is completed.

A specimen of the type shown in FIG. 6 for which the user wants to know the amount of unbalance is set in a dynamic balance tester and an unbalance test is started. A static unbalance amount S is obtained from the unbalance vector amounts L and R calculated based on the outputs from the left and right pickups 9 and 10, and this S is substituted into y in the equation (3) to elastically deform the specimen. Is displayed on the display 21L or 22R. Therefore, the operator adds the weight of the additional weight displayed on the display to the center of the test sample and performs the dynamic balance test again. Then, the same operation is repeated until the unbalance amount displayed on the display becomes equal to or less than the allowable value.

Thereafter, the dynamic imbalance on the left and right surfaces of the test specimen whose static imbalance has been corrected is measured. The left and right unbalance amounts and unbalance positions are displayed on the indicators 21L and 21R by the unbalance vector amounts L and R based on the output signals from the left and right pickups 9 and 10. The operator corrects the two surfaces by adding an additional weight of a predetermined weight to a predetermined position based on the display content of the display. Note that reference numeral 19 in FIG.
Indicates the corrected weight of each side.

FIG. 3 is a flowchart showing a procedure when such measurement and correction work is automated. In step S1, the specimen is rotated and the output signals from the pickups 9 and 10 are read. In step S2, it is determined whether the correction of static imbalance has been completed.
Then, the static imbalance amount S is calculated from the measured values of the left and right pickups 9, 10. Next, in step S4, based on equation (3), the weight x of the weight to be added to correct the static imbalance of the elastically deformed specimen is calculated, and in step S5, the value is displayed on the display 21L or 21R. indicate.
Thereafter, in step S6, the process waits until the additional weight is added and the correction operation is completed.
7, an unbalance test is performed again, output signals from the right and left pickups 9 and 10 are read, and a static unbalance amount and a two-side unbalance amount are calculated based on the output signals of the pickups in step S8. It is determined whether the value has become equal to or less than the allowable value. If this step S8 is affirmed, the operation ends, and if it is denied, the process returns to step S2.

In step S2, if the static imbalance correction has been completed, the process proceeds to step S9, where a two-plane balance calculation is performed based on the measurement signals from the left and right pickups 9 and 10, and the unbalance vector amounts L and R are calculated. Is calculated, and step S1
When the value is 0, the unbalance amounts of the respective surfaces are displayed on the indicators 21L and 21R, and the process proceeds to step S6.

In the above description, as shown in FIG. 2, the correction calculation of the unbalance amount is performed based on the correspondence between the weight of the additional weight and the static unbalance amount, but FIGS. 4 (a) and 4 (b). The corresponding relationship between the detection signals SL and SR from the left and right pick-ups and the weight x of the additional weight as shown in FIG. 3 is obtained, and each output signal from the pickup is corrected by the corresponding relationship.
That is, g1 ^-1 (x) and g2 ^-1 corresponding to the characteristic C in FIG.
(X) may be multiplied and corrected, and the unbalance amount may be calculated based on the corrected detection signal.

FIG. 5 shows an example of the configuration. The same parts as those in FIG. 1 are described with the same reference numerals. Outputs of the left and right pickups 9 and 10 are input to amplifiers 11 and 12. The outputs of the amplifiers 11 and 12 are A / D converters 31,
At 32, it is converted to a digital value and input to the correction units 33L and 33R. The correction units 33L and 33R are shown in FIG.
Based on the correspondence shown in (b), the detection signals of the left and right pickups are added to the function g1 corresponding to the characteristic C in FIG.
^-1 (x) and g2 ^-1 (x), and the resulting signal is input to the CPU 34. The CPU 34 calculates the static imbalance amount S from the corrected detection signal, and displays the weight to be added for correction based on the static imbalance amount S on the display 35L,
Display at 35R.

In the above description, as shown in FIG. 6, the axis of the specimen is connected via an elastic body such as rubber, and when the specimen is set on the dynamic balance testing machine and rotated, the axis of the specimen is aligned. 7
Although the case of bending as shown in (a) has been described, the present invention is not limited to such a specimen, but is elongated such that the shaft center is bent as shown in FIG. The same correction calculation can be performed for a specimen having high rigidity.

In the configuration of the above embodiment, the pickups 9 and 10 are the detecting means, the calculating section 13a is the unbalance amount calculating means and the first and second unbalance amount calculating means, and the storage section 13b is the correspondence calculating section. And the correction unit 13c constitutes a correction unit.

[0021]

As described above in detail, according to the present invention, various sizes of weights are added to a dummy specimen whose axis is bent and whose unbalance amount has been corrected to almost zero beforehand and rotates. , The detected value or unbalance amount at that time is obtained,
The correspondence between the weight of the added weight and the detected detection signal or the calculated unbalance amount is calculated, and the calculation is performed by the calculation means for the specimen whose shaft is bent and rotated during the unbalance measurement. Since the unbalance amount of the specimen is corrected based on the above-described correspondence relationship, or the detection signal from the detection means is corrected based on the above-described correspondence relationship, and the unbalance amount is calculated, the shaft center is bent and rotated. The efficiency of the correction work is improved even with the test specimen which is performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of a dynamic balance tester according to the present invention.

FIG. 2 is a diagram for explaining a relationship between an additional weight and a corresponding static imbalance amount;

FIG. 3 is a flowchart showing an example of a measurement procedure of the dynamic balance tester according to the present invention.

FIG. 4 is a diagram showing a correspondence relationship used in a correction unit of the dynamic balance tester in FIG. 5;

FIG. 5 is a diagram showing the overall configuration of another embodiment of the dynamic balance tester according to the present invention.

FIG. 6 is a diagram illustrating an example of a specimen that rotates with its axis bent.

7A is a diagram illustrating a state where the axis of the test sample in FIG. 6 is bent during rotation, and FIG. 7B is a diagram illustrating a case where the entire test sample main body is bent when rotating at high speed.

[Explanation of symbols]

 1 Specimen 9, 10 Pickup 13a Operation unit 13b Storage unit 13c, 33L, 33R Correction unit 21L, 21R, 35L, 35R Display

Claims (2)

(57) [Claims] 1. A dynamic balance tester capable of calculating an unbalance amount of a specimen rotating with an axis bent, and detecting a vibration or a centrifugal force corresponding to the unbalance amount of the rotationally driven specimen. Detecting means for calculating the unbalance amount of the test object from the vibration or centrifugal force detected by the detecting means assuming that the test object does not bend during rotation; and Weights of various sizes are added to a substantially central portion of a dummy specimen whose axis is bent and rotated, which has been corrected to substantially zero in advance, and the arithmetic means is based on a detection result detected by the detection means at that time. And a correspondence calculating means for calculating a correspondence between the unbalance amount calculated in the above and the weight of the added weight; and for a specimen whose axis is bent and rotated, the correspondence calculation means calculates the correspondence. Based on the corresponding relationship A dynamic balance tester, comprising: a correcting unit configured to correct the unbalance amount calculated by the unit. 2. A dynamic balance tester capable of calculating an unbalance amount of a specimen rotating with an axis bent, and detecting a vibration or a centrifugal force corresponding to the unbalance amount of the rotationally driven specimen. Detecting means for adding weights of various sizes to a substantially central portion of a rotating dummy specimen whose axis is bent and whose unbalance amount has been corrected to substantially zero in advance, and which is detected by the detecting means at that time. Calculating means for calculating the correspondence between the detection result and the weight of the added weight; correcting the detection result detected by the detection means based on the correspondence calculated by the correspondence calculation means. A dynamic balance tester comprising: a correcting means for calculating an unbalance amount based on a detection signal corrected by the correcting means.