JPH0617843B2 - Eccentricity compensation method for dynamic balance tester - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentricity compensating method for compensating for eccentricity of a mounting jig of a dynamic balance testing machine for mounting a device under test.

2. Description of the Related Art Since the mounting jig for mounting the DUT is not ideal and has eccentricity, it is necessary to compensate for it. Therefore, conventionally, an unbalanced DUT is first mounted on a mounting jig at 0 degree to measure the eccentricity vector, and then at a mounting angle of 180 degrees to measure the eccentricity vector again. Or measure each eccentricity vector at an angle of 180 degrees to each other. Then, the two eccentricity vectors obtained by this measurement are combined, and the eccentricity vector of only the attachment jig from which the unbalance amount of the test object is removed is taken out. Since the eccentricity compensation vector has the same length as that of the eccentricity vector and is 180 degrees different in direction, a compensation voltage corresponding to the eccentricity compensation vector is generated by the compensation voltage generating circuit.

Problems to be Solved by the Invention When a compensation voltage is generated by the above method, for example, when the DUT is an elastic body such as a tire, a detachment error or the like that occurs when the DUT is attached to a mounting jig, etc. It was difficult to prevent the accuracy of eccentricity compensation from deteriorating due to the mounting error.

The present invention has been invented to solve the above problems, and an object of the present invention is to provide an eccentricity compensation method for a dynamic balance tester capable of performing highly accurate eccentricity compensation even when the DUT is an elastic body. I am trying.

Means for Solving the Problems In order to achieve the above object, an eccentricity compensating method for a dynamic balance testing machine of the present invention is performed by sequentially changing a mounting angle of a DUT with respect to a mounting jig over the entire circumference. A step of measuring a plurality of times, a step of plotting a plurality of eccentricity vectors obtained by the measurement on a graph and combining them, and a compensating voltage generating circuit for compensating an eccentricity compensation voltage corresponding to the eccentricity compensation vector obtained by the combining And the step of generating by.

Action Desorption errors occur in random directions when measuring over the entire circumference. In the step of synthesizing the eccentricity vector obtained at this time, the desorption errors in random directions cancel each other out, and the decentering compensation vector obtained as a result has less influence by the desorption error. Then, the eccentricity of the mounting jig is compensated on the basis of the eccentricity compensation vector in which the influence of the detachment error is reduced.

Embodiment FIG. 1 is a block diagram of a dynamic balance testing machine used in one embodiment of the present invention. In the figure, the spindle 11 rotates a mounting jig 12 to which a tire 13 as a test object is mounted,
The mechanical vibration generated at that time is guided to the pickup 21, converted into an electric signal, and then guided to the amplifier circuit 22. The amplifier circuit 22 is provided with a pickup signal cutoff switch 32 for setting its output to 0V. The output of the amplifier circuit 22 is connected to one input of an adder circuit 24 via a calibration circuit 23, and the compensating voltage generating circuit 27 for generating the eccentricity compensating voltage of the mounting jig 12 in the X and Y directions is connected to the other input. The output of is connected through a chopper circuit 28. The output of the adder circuit 24 is guided to the synchronous rectification circuit 25 that separates the components in each of the X and Y directions, and is output as a DC voltage indicating the amount in each direction. The two outputs are guided to the display circuit 26 and converted into a signal indicating the amount of unbalance and a signal indicating the angle of unbalance, and an unbalance amount meter 30 indicating the amount of unbalance.
Swing the unbalanced angle meter 31. The rotation detector 14 generates one rotation pulse each time the mounting jig 12 makes one rotation, and this rotation pulse is sent to the rectangular wave generation circuit 29. Then, in this output, two pulses appearing which are 90 degrees out of phase with each other and which are synchronized with the rotation pulse. The two pulses are sent to the synchronous rectification circuit 25 and the chopper circuit 28, respectively. The configuration for detecting the mechanical vibration on the left side of the main shaft 11 is shown, but the mechanical vibration on the right side is also displayed by the configuration similar to the above.

The operation will be described below.

The pickup signal cutoff switch 32 is switched so that the output of the amplifier circuit 22 becomes the signal from the pickup 21, and the tire 13 with a weight is attached to the attachment jig 12. When the main shaft 11 is rotated by a drive unit (not shown), the main shaft 11 vibrates due to the eccentricity of the mounting jig 12 and the imbalance of the tire 13, and a voltage proportional to the vibration is generated in the pickup 21. The calibration circuit 23 calibrates the corrected surface separation and the unbalance amount meter 30.

The trial weight is removed from the tire 13 and rotated, and the instructions of the unbalance amount meter 30 and the unbalance angle meter 31 are read. Then, the tire 13 is rotated 45 degrees with respect to the mounting jig 12, and the instruction is read in the same manner as above. Tires 13 in 45 degree sequence
When the instruction is read while rotating with respect to the mounting jig 12, eight eccentricity vectors are obtained.

FIG. 2 is a graph showing eight eccentricity vectors and eccentricity compensation vectors. With respect to the eccentricity vector obtained by eight times of measurement, the tip portions (a to h) are plotted with 0 as the origin, and the circumference k connecting the tip portions (a to h) is drawn. The vector obtained by combining the eccentricity vectors is indicated by a vector m directed from the origin 0 of the graph to the center P of the circumference K, and the vector n obtained by rotating the direction of this vector m by 180 degrees becomes the eccentricity compensation vector.

Return to FIG. When the pickup signal is cut off by the pickup signal cut-off switch 32, the instructions of the unbalance amount meter 30 and the unbalance angle meter 31 become zero. Next, the compensation voltage generation circuit 27 causes the compensation voltage generation circuit 27 to generate an eccentricity compensation voltage so that the instruction becomes a value corresponding to the eccentricity compensation vector n.

The same operation as above is performed for the block that displays the vibration on the right side of the main shaft 11.

Note that the present invention is not limited to the above-mentioned examples, and the DUT 13 can be applied to a rotating body made of an elastic body in addition to the tire, and the angle is sequentially changed with respect to the mounting jig 12. The rotation angle when attaching the DUT 17 is not limited to 45 degrees, and can be any angle such as 30 degrees or 60 degrees. The smaller the angle, the more the eccentricity is compensated. It is possible to improve accuracy.

Effect of the Invention Since the DUT is measured by sequentially changing the mounting angle with respect to the mounting jig over the entire circumference to compensate the eccentricity of the mounting jig, the accuracy can be improved even when the DUT is an elastic body. It is possible to provide an eccentricity compensating method for a dynamic balance tester capable of performing high eccentricity compensation.

[Brief description of drawings]

FIG. 1 is a block diagram of a dynamic balance tester used in an embodiment of the present invention, and FIG. 2 is a graph showing eight eccentricity vectors and eccentricity compensation vectors. 12 ... Mounting jig, 13 ... DUT, 27 ... Compensation voltage generation circuit, n ... Eccentricity compensation vector.

Claims (1)

[Claims] 1. In an eccentricity compensation for compensating the eccentricity of a mounting jig by mounting an object to be tested on a mounting jig of a dynamic balance testing machine and measuring an eccentricity vector, the mounting object is fixed to the mounting jig. A step of measuring a plurality of times of measuring the mounting eccentricity vector by sequentially changing the mounting angle with respect to the tool, a step of plotting a plurality of eccentricity vectors obtained by the measurement and synthesizing them, and And a step of generating an eccentricity compensation voltage corresponding to the eccentricity compensation vector obtained by combining by a compensation voltage generating circuit.