JPH07218372A - Dynamic balancing testing machine - Google Patents

Abstract

PURPOSE:To provide a dynamic balancing testing machine which can calculate the unbalancing amount of a rotating specimen due to deflection of a rotary shaft center at the time of measuring. CONSTITUTION:A dummy specimen rotated due to deflection of a shaft center in which an unbalancing amount is previously corrected to substantially zero is prepared, weights of various sizes are added to its substantially center, and static unbalancing amounts are obtained for respective added weights by a calculator 13a based on detected results detected by pickups 9, 10 at this time. Corresponding relationship between the weight of the added weight and the detected static unbalancing amount is stored in a memory 13b. The calculator 13a calculates a function for representing a curve stored in the memory 13b. The unbalancing amount of the element under test calculated by the calculator 13a is corrected by a corrector 13c based on the function indicating the relationship for the rotation specimen due to the deflection of the shaft center at the time of measuring the unbalance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic balance tester suitable for measuring the imbalance of a rotating test piece,
In particular, the present invention relates to a dynamic balance tester capable of calculating an unbalanced amount of a test piece in which the shaft center is bent during rotation.

[0002]

2. Description of the Related Art In a known dynamic balance tester, a pair of shaft portions of a slender columnar specimen such as a motor rotor is supported by a holder, and vibration or vibration of the holder when the specimen is rotated by a belt is performed. The centrifugal force is measured with a pickup. The output signal from the pickup is input to the arithmetic circuit, and the unbalance amount and the unbalance position of the left and right shafts 2 are calculated and displayed. For example, when manually correcting the imbalance, if the rotor has a bend, the normal tester displays the weight and position of the weight to be added as if there is no bend, so the operator can check the displayed contents. The weight and the position of the weight to be added are empirically determined, and the correction weight is added to the predetermined position of the specimen.

[0003]

Conventionally, the specimen is regarded as a rigid body, that is, it is assumed that the shaft center does not bend during rotation, and the left and right are corrected based on the measurement signals from the pair of left and right pickups. Since a predetermined amount of imbalance between the two surfaces is calculated and displayed, there are the following problems. As shown in FIG. 6, the test piece main body 51, which is a rotating body, has shaft portions 52 protruding from both ends thereof connected to each other through elastic body couplings 53 such as rubber. Even if it is corrected, when the shaft portion 52 is supported on the holder and rotated, the shaft center bends and rotates as shown in FIG. 7A. There is a disproportion between the case where there is an imbalance in the specimen that causes the shaft to bend and rotate, and the case where there is a disproportion in the case where the specimen has a rigidity that causes the shaft to rotate without bending. Even if the unbalanced amount is the same,
Weights added for correction are different.

FIG. 2 is a diagram in which the horizontal axis represents the weight of the weight added to the center of the test piece, and the vertical axis represents the static unbalance amount. Assuming that the unbalance of the test piece is corrected to almost zero in advance, if the test piece is a rigid body, as shown by the broken line a, the static unbalance amount is also in direct proportion to the increase in the weight of the weight to be added. 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 in direct proportion, and as shown by the solid line b, compared with the case of the rigid specimen. A large amount of static imbalance appears due to elastic deformation. That is, the weight of the weight to be added to correct the unbalance amount displayed on the display unit needs to be smaller in the elastically deformed sample than in the rigid sample.

However, the solid line b in FIG. 2 differs depending on the degree of elastic deformation, and based on the unbalance amount calculated and displayed with the rigid sample as a reference,
It is difficult for a skilled person to judge the weight of the weight added to the elastically deformed sample. Therefore, it is necessary to correct the imbalance while adjusting the weight to be added, which causes a problem of poor workability.

An object of the present invention is to provide a dynamic balance tester capable of calculating an unbalanced amount of a test piece which rotates due to bending of a rotation axis during measurement.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a dynamic balance tester capable of calculating the unbalance amount of a rotating sample with its shaft center flexed. An unbalance amount that calculates the unbalance amount of the test piece on the assumption that the test piece does not bend during rotation from the detection means that detects the corresponding vibration or centrifugal force and the vibration or centrifugal force detected by this detection means. Weights of various sizes are added to the arithmetic means and the dummy test piece whose axial center is bent and rotated in which the unbalance amount is corrected to substantially zero in advance, and the weight is detected by the detecting means at that time. Correspondence calculation means for calculating a correspondence relationship between the unbalance amount calculated by the calculation means based on the detection result and the weight of the added weight, and the test piece whose axis is bent and rotated, Correspondence calculated by correspondence 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 obtained, and for the test piece whose axis is bent and rotates, the detection result of the detection means is corrected based on the correspondence obtained in advance. Alternatively, the unbalance amount may be obtained.

[0008]

[Function] A dummy test piece is prepared in which the unbalance amount is corrected to substantially zero in advance and the shaft is bent and rotated, and weights of various sizes are added to the substantially central portion thereof, and at that time, it is detected by the detection means. The unbalance amount is obtained for each weight by the unbalance calculation means based on the detection result. The correspondence calculating means calculates, for example, the correspondence between the weight of the added weight and the calculated unbalance amount. For a specimen that rotates with its axis bent during imbalance measurement, the calculation means calculates 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 sample 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 obtained as in claim 2, the detection result of the detection means is based on the above-mentioned correspondence relation for the test piece whose axis is bent and rotates. And the unbalance amount is calculated based on the corrected detection result.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an embodiment of a dynamic balance testing machine to which the present invention is applied. The shafts 2 and 3 at both ends of the sample 1 are held on bearings 6 and 7 elastically supported by springs 4 and 5, and the sample 1 is rotated by a motor 17 via a belt 8. Pickups 9 and 10 for measuring the vibrational displacement due to the imbalance of the test piece 1 are connected to the bearings 6 and 7, respectively, and the detection signals from the pickups 9 and 10 are passed through amplification / filter circuits 11 and 12 to an arithmetic circuit. Taken in 13. Reference numeral 14 is a mark printed at the reference position of the test piece, and 15 is a photo sensor arranged to face 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 the correction part 13c are provided. The calculation unit 13a includes a detection signal from the pickups 9 and 10 and a photo sensor 15
The unbalance amount and the unbalanced position are calculated based on the reference position signal from. Here, the unbalance amount and the unbalance position are calculated as a rigid test piece whose axis is not bent during rotation. The correction data is stored in the storage unit 13b as follows.

Prior to the measurement, dummy elastically deformed dummy specimens as shown in FIGS. 6 and 7 in which the imbalance is corrected to almost zero are prepared in advance. This dummy test piece is set in the dynamic balance tester, and a weight is added to the center of the test piece to measure the amount of unbalance. The weight x of the additional weight is increased for each predetermined unit, and the unbalance amount is measured for each weight. When the unbalanced measured value based on the detection signal from the left pickup 9 is represented by a vector amount L and the unbalanced measured 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.
The graph shown by the solid line b in FIG. 2 is obtained in which the horizontal axis represents the weight x of the additional weight and the vertical axis represents the static unbalance vector amount S. The correspondence between the weight x of the additional weight and the static imbalance amount S is stored in the storage unit 13b.

Here, the computing 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 the least square method or the polygonal line approximation method, and the inverse function f (x) of this function. ^-1 is asked. The solid line c in FIG. 2 is the inverse function f
It is a curve shown by (x) ⁻¹ . here,

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

## EQU2 ## It can be obtained as f (x) ^-1 = 1 / f (x) (2). In this way, the calculation unit 1
3a is the solid line c in FIG.

## EQU3 ## Calculation is performed as y = f (x) ^-1 = 1 / f (x) (3) to complete the preparation for measurement.

An unbalance test is started by setting a test piece of the type shown in FIG. 6 in which the amount of unbalance is desired to be set in a dynamic balance tester. The static imbalance amount S is calculated from the imbalance 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 of the equation (3) to elastically deform the sample. The weight x of the additional weight necessary for correcting the imbalance of the above 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 piece, and performs the dynamic balance test again. Then, the same operation is repeated until the unbalance amount displayed on the display unit becomes equal to or less than the allowable value.

After that, the dynamic imbalance between the left and right surfaces of the specimen whose static imbalance has been corrected is measured. The left and right unbalance amounts and unbalance positions are displayed on the display devices 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. Based on the display content of the display, the operator adds an additional weight of a predetermined weight to a predetermined position to perform the two-sided correction. Note that reference numeral 19 in FIG.
Indicates the corrected weights on the left and right sides.

FIG. 3 is a flow chart showing a procedure for automating such measurement and correction work. In step S1, the sample is rotated and the output signals from the pickups 9 and 10 are read. In step S2, it is determined whether the static imbalance correction is completed. If not, step S3
The static unbalance amount S is calculated from the measured values of the left and right pickups 9 and. Next, in step S4, the weight x of the weight added to correct the static imbalance of the elastically deformed sample is calculated based on the equation (3), and the calculated value is displayed in the display 21L or 21R in step S5. indicate.
After that, in step S6, the additional weight is added to wait until the correction work is completed, and when the correction work is completed, the step S6 is performed.
In step 7, the unbalance test is performed again, the output signals from the left and right pickups 9 and 10 are read, and in step S8, the static unbalance amount and the two-side unbalance amount are calculated based on the output signals of the pickups, and both are It is determined whether or not the value is below the allowable value. If this step S8 is affirmed, the work is ended, and if not, the process returns to step S2.

In step S2, if the static imbalance correction is completed, the process proceeds to step S9, in which the two-face balance calculation is performed based on the measurement signals from the left and right pickups 9 and 10 to calculate the imbalance vector amounts L and R. Is calculated, and step S1
When the value is 0, the unbalance amount of each surface is displayed on each of the display devices 21L and 21R, and the process proceeds to step S6.

In the above, as shown in FIG. 2, the unbalance amount correction calculation is performed based on the correspondence between the weight of the additional weight and the static unbalance amount. As shown in each of the above, the respective correspondence relationship between the detection signals SL and SR from the left and right pick-ups and the weight x of the additional weight is obtained, and the respective output signals from the pickup are corrected by this correspondence relationship,
That is, g1 ^-1 (x) and g2 ^-1 corresponding to the characteristic C of FIG.
A configuration may be used in which (x) is multiplied for correction, and the unbalance amount is calculated based on the corrected detection signal.

FIG. 5 shows an example of the configuration. The same parts as those in FIG. 1 are designated by the same reference numerals for description. The 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 converter 31,
It is converted into a digital value at 32 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 function g1 corresponding to the characteristic C of FIG.
^-1 (x) and g2 ^-1 (x) are multiplied, 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 weight to be added based on this value to correct the weight 35,
Display on 35R.

In the above, as shown in FIG. 6, the shaft of the test piece is connected through the elastic body such as rubber, and when the test piece is set in the dynamic balance tester and rotated, the axis of the test piece is set to the figure. 7
Although the case of bending as shown in (a) has been described, the present invention is not limited to such a test piece, and a long and slender shaft whose center is bent by centrifugal force during high-speed rotation as shown in FIG. 7 (b). The same correction calculation can be performed on a specimen having high rigidity.

In the structure of the above embodiment, the pickups 9 and 10 serve as the detection means, the computing unit 13a serves as the unbalance amount computing means and the first and second unbalance amount computing means, and the storage unit 13b computes the correspondence relationship. The correction unit 13c constitutes a correction unit.

[0021]

As described in detail above, according to the present invention, weights of various sizes are added to the dummy test piece whose unbalance amount is corrected in advance to substantially zero and which is bent and rotates. , Find the detected value or unbalanced amount at that time,
The correspondence between the weight of the added weight and the detected detection signal or the calculated unbalance amount was calculated, and for the specimen whose shaft center flexed and rotated during the unbalance measurement, it was calculated by the calculating means. The unbalance amount of the sample is corrected based on the above correspondence, or the unbalance amount is calculated after correcting the detection signal from the detection means according to the above correspondence, so that the shaft center bends and rotates. The efficiency of the correction work is improved even for the specimen to be used.

[Brief description of 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 illustrating a relationship between an additional weight and a static imbalance amount corresponding to the additional weight.

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 testing machine of FIG.

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 showing an example of a test piece whose axis is bent and rotates.

7A is a diagram showing a state where the shaft center of the specimen of FIG. 6 is bent during rotation, and FIG. 7B is a diagram showing a case where the entire specimen main body is bent during high-speed rotation.

[Explanation of symbols]

 1 Specimen 9, 10 Pickup 13a Calculation part 13b Storage part 13c, 33L, 33R Correction part 21L, 21R, 35L, 35R Indicator

Claims (2)

[Claims] 1. A dynamic balance tester capable of calculating an unbalanced amount of a test piece that rotates with its axis bent, and detects vibration or centrifugal force according to the unbalanced amount of the rotationally driven test piece. An unbalance amount calculating means for calculating the unbalance amount of the sample under the assumption that the sample is not bent during rotation from the vibration or centrifugal force detected by the detecting means; Weights of various sizes are added to the substantially central portion of the dummy test piece whose axis is bent and rotated, which has been corrected to substantially zero in advance, and the arithmetic means is based on the detection result detected by the detection means at that time. Correspondence calculating means for calculating the correspondence between the unbalance amount calculated in step 1 and the weight of the added weight; and for the sample whose axis is bent and rotated, the correspondence calculating means is used. Based on the correspondence relationship A dynamic balance testing machine, comprising: a correction unit that corrects the unbalance amount calculated by the unit. 2. A dynamic balance tester capable of calculating an unbalanced amount of a test piece that rotates by bending its axis, and detects vibration or centrifugal force according to the unbalanced amount of the test piece that is rotationally driven. Detecting means for adjusting the unbalance amount to approximately zero in advance, by adding weights of various sizes to the substantially central portion of the dummy test piece whose shaft center bends and rotates, and which is detected by the detecting means at that time. Correspondence detection means for calculating a correspondence relation between the detection result of the weight and the weight of the added weight; the detection result detected by the detection means is corrected based on the correspondence relation calculated by the correspondence relation calculation means. A dynamic balance testing machine, comprising: a correction unit for performing the calculation; and an unbalance calculation unit for calculating an unbalance amount based on the detection signal corrected by the correction unit.