JP7257946B2 - METHOD AND DEVICE FOR MECHANICAL COUPLING DETERMINATION - Google Patents

Description

The present disclosure relates to a method for determining mechanical coupling of a rotational position detector and a device for determining mechanical coupling.

Patent Literature 1 below discloses a method of measuring an error of a position detector as a product based on the position of a master position detector.

JP 2014-153294 A

In a rotational position detector that measures errors based on a master detector and creates correction data, in order to mechanically connect the master detector and this rotational position detector, for example, a tapered male and female are used. It is considered to have a structure to fasten with screws, tighten the screws by a robot or the like, and perform automatic measurement. If the machining is bad and the taper angles do not match, a large runout will occur during measurement. For this reason, if the stator side of the position detector of Patent Document 1 is fixed by a coupling, an error due to mechanical coupling that cannot be absorbed by the coupling will be mixed in the correction data, degrading the accuracy of the rotational position detector. I have an exacerbating problem. In addition, even if the taper coupling is incompletely tightened, the problem of error due to mechanical coupling also occurs.

An object of the present invention is to determine the quality of such mechanical coupling. This enables, for example, inspection of a rotational position detector that guarantees high position detection accuracy.

A method for determining a mechanical connection according to the present invention is a method implemented in the inspection of a rotational position detector using a tester, wherein A) the tester has a tapered or straight shape at its tip. a tester rotating shaft having a portion, a fixed portion that supports the tester rotating shaft, and a master detector that detects the rotational position of the tester rotating shaft, and B) the rotational position detector is the fitting portion a detector rotating shaft formed with a fitted portion to be fitted to the detector rotating shaft; a rotor provided on the detector rotating shaft; a stator provided around the rotor; a housing to which the stator is fixed; a coupling fixed to the housing; and a calculator for calculating the rotational position of the detector rotating shaft based on the electromagnetic action of the rotor on the stator; The fitted portion of the rotating shaft of the device is concentrically fitted to the fitting portion of the rotating shaft of the tester and screwed to perform mechanical coupling, and the rotational position detector of the A coupling is screwed to the fixed part of the tester to provide a mechanical connection, and D) the method comprises calculating the rotational position calculated by the calculating part based on the rotational position detected by the master detector. A positional angular error is obtained, and based on the magnitude of an error component of 20 cycles or less obtained by Fourier transforming the angular error, the mechanical coupling about the detector rotation axis or the coupling A determination is made as to whether the mechanical coupling is good or bad.

In the pass/fail judgment, the pass/fail of the mechanical coupling can be judged by comparing the low-order error component of 20 cycles or less with, for example, a judgment value obtained in advance by experiment.

A device for determining a mechanical connection according to the present invention includes means for inputting an angle error of a rotation axis obtained by an inspection of the rotation position detector which is performed by mechanically coupling the rotation position detector to a tester; means for performing a Fourier transform on the error; means for determining whether the mechanical coupling between the tester and the rotational position detector is good or bad based on the magnitude of the error component of 20 cycles or less obtained by the Fourier transform; characterized by comprising

According to the present invention, it is possible to determine the quality of the mechanical connection between the tester and the rotational position detector, such as the rotation axis. Therefore, for example, it can be expected to improve the accuracy of inspection of the rotational position detector by a tester.

Fourier transform is performed on the angular error when the screw is incompletely tightened, and inverse Fourier transform is performed on the error of 3 to 20 cycles per rotation that appears only in an abnormal state. It is a figure which shows the joint structure of the rotational position detector and master detector which concern on this embodiment.

An embodiment of a method for determining a mechanical coupling error of a rotational position detector according to this embodiment will be described below with reference to the drawings. FIG. 2 is a diagram showing a coupling structure between a rotational position detector and a master detector. The rotational position detector consists of a detection rotor 1, a center bolt 2, a housing 6, a shaft 3, bearings 4, 5, a stator 7, a die 8, a substrate 9, and a coupling 10. Bearings 4, 5 are press-fitted to the shaft 3. The bearings 4 and 5 are bonded to the housing 6 so that there is no bearing clearance. The detection rotor 1 is a magnetic rotor plate with 125 irregularities arranged along the circumference. 3 is glued and fixed.

The stator 7 is a punched core made of silicon steel or the like, has pole teeth arranged opposite to the detection rotor 1, and is wound around the pole teeth to output a sine wave detection signal corresponding to the unevenness of the detection rotor 1. A rotational position is calculated at 9, which is fixed to the housing 6 via a die 8 and a substrate 9 by screwing. Further, the coupling 10 is screw-fixed to the housing 6 at two points with a phase of 180 degrees.

The tester consists of a shaft 20, bearings 21, 22, a fixed part 23, a coupling 24, a motor 25, and a master detector 30. The bearings 21, 22 are press-fitted to the shaft 20, and the bearings 21, 22 The motor 25 is rotated by a control device (not shown), and the rotation is caused by the shaft 20 and the master detector 30 fixed to the shaft 20 via the coupling 24. , rotates the shaft 3 of the rotary position detector coupled to the shaft 20 .

In order to measure the correction value of the rotational position detector, the shaft 3 is fixed to the shaft 20 of the tester with the center bolt 2 using an electric screwdriver held by a robot (not shown), and the coupling 10 is fixed by the screw 31. Then, when the motor 25 is rotated by screwing the motor 25 onto the fixed portion 23 of the tester at two points of 180 degrees phase, the difference between the positions of the rotational position detector and the master detector is Determined by the controller.

In the inspection method configured in this way, if the taper angles of the shafts 3 and 20 do not match due to a processing error or the like, a large deflection occurs during measurement and cannot be absorbed by the coupling 10. , 2-cycle errors are mixed in the correction data, degrading the accuracy of the rotational position detector. In addition, if the screws are not completely tightened, the tapered portions are loosely connected, causing slippage and looseness, which causes an error of 3 to 20 cycles.

By screwing the coupling 10 at two 180-degree diagonal points, the spring characteristics of the coupling 10 can absorb the one-period motion error caused by misalignment. However, if the shape of the coupling 10 is not completely symmetrical, the spring characteristics will not be symmetrical, and a motion error of one or two cycles will remain. Further, when the taper is loosely screwed, the rotational rigidity due to the coupling changes depending on the rotational phase. For this reason, the transmission of rotational motion fluctuates irregularly due to the force generated by misalignment. This results in a position detection error, and this error component appears within 20 cycles.

FIG. 1 shows the Fourier transform of the angle error when the screw is incompletely tightened, and the inverse Fourier transform of the error of 3 to 20 cycles per rotation that appears only in an abnormal state. If the difference between the maximum value and the minimum value of this error exceeds the pass/fail judgment criteria, the product inspection is rejected, thereby preventing the wrong correction value from being written into the product and shipped. Establishing such an inspection standard is a very important technology for automatic production by robots.

In addition, if the taper angle does not match due to processing error, etc., the error measured in the same way is Fourier transformed, and if the amount of error in one cycle or two cycles per rotation exceeds the pass/fail judgment criteria, product inspection can be rejected.

Therefore, according to the present embodiment, the pass/fail judgment value for such a mechanical coupling error is determined based on the periodic component contained in the measured error, thereby ensuring a high position detection accuracy. can be expected to realize the inspection of

1 detection rotor, 2 center bolt, 3 shaft, 6 housing, 4, 5 bearing, 7 stator, 8 die, 9 substrate, 10 coupling, 20 shaft, 21, 22 bearing, 23 fixed part, 24 coupling, 25 motor , 30 master detector, 31 screw.

Claims (2)

A method practiced in testing a rotary position detector using a tester, comprising:
A) the tester is
a tester rotating shaft having a tapered or straight fitting portion at the tip;
a fixed part that supports the tester rotating shaft;
A master detector that detects the rotational position of the tester rotating shaft,
B) the rotational position detector,
a detector rotating shaft formed with a fitted portion that fits into the fitting portion;
a rotor provided on the detector rotating shaft;
a stator provided around the rotor;
a housing to which the stator is fixed;
a coupling secured to the housing;
a calculation unit that calculates the rotational position of the detector rotation shaft based on the electromagnetic action of the rotor on the stator,
C) At the time of inspection,
The fitted portion of the detector rotating shaft is concentrically fitted to the fitting portion of the tester rotating shaft and screwed to perform mechanical coupling,
the coupling of the rotational position detector is screwed to the fixed portion of the tester for mechanical coupling;
D) in the method,
Obtaining an angular error of the rotational position calculated by the calculation unit based on the rotational position detected by the master detector;
Based on the magnitude of the error component of 20 cycles or less obtained by Fourier transforming the angular error, the quality of the mechanical coupling about the detector rotation axis or the mechanical coupling about the coupling make a decision,
A method for determining mechanical coupling, characterized by: means for inputting an angular error of the rotational axis obtained by testing the rotational position detector by mechanically coupling the rotational position detector to the tester;
means for performing a Fourier transform on the angular error;
means for judging whether the mechanical coupling between the tester and the rotational position detector is good or bad based on the size of the error component of 20 cycles or less obtained by the Fourier transform;
A mechanical coupling determination device comprising:

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