JPH08247883A - Rotor imbalance measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object of the present invention to provide an imbalance measuring device for a rotating body capable of reliably measuring even a slight imbalance. [Structure] An unbalance measuring device 20 for a rotating body of a grindstone rotating device 10 having a motor 14, rotating bodies 11, 12, 14a rotated by the motor 14, and a housing 15 for mounting the motor 14. This measuring device 2
Reference numeral 0 denotes a rotation angle detection sensor 17 which is attached to the motor shaft 14a and detects this rotation angle when the rotating body rotates,
Attached to the housing 15 and the housing 15
And a stable base portion 21 interposed between the force detecting sensor 22 and the stable base portion 21. The force detecting sensor 22 detects a change in the force applied to the housing 15 by the rotation of the rotating body, and the rotation angle and the force detecting sensor detected by the rotation angle detecting sensor 17. And a processing device 23 for measuring the position and amount of the imbalance based on the fluctuation of the force detected by 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body unbalance measuring device for measuring the position and amount of unbalance of a rotating body, and more particularly to a rotating mechanism of an ultra-precision machine. The present invention relates to an unbalance measuring device for a rotating body including a grindstone to be used and a shaft to which the grindstone is attached.

[0002]

2. Description of the Related Art In general, when a motor or the like rotates, a rotor or other rotating body swirls due to a weight imbalance with respect to a rotating shaft, which affects the stator side as well, so that the entire apparatus housing the motor is affected. It is known that vibration occurs and causes various adverse effects. For example, in an automobile, if there is a weight imbalance in the tire portion, unpleasant vibration is generated in the vehicle while traveling, or the tire shaft receives repeated force, and as a result, the shaft is damaged,
A serious accident may occur.

In the grindstone rotating device of the ultra-precision processing machine, which performs processing requiring accuracy of 1 μm or less, which is called ultra-precision processing, the problem of imbalance is a particularly important problem in terms of processing accuracy. In particular, in a rotating body such as a grindstone for processing a workpiece and a shaft attached with the grindstone,
Since it rotates at several thousands to tens of thousands rpm, even if there is a slight imbalance, it is clear that vibration of several μm level or more occurs in the grinding wheel rotating device, adversely affecting the processing accuracy of the ultra-precision processing machine. It has become.

Conventionally, the problem of imbalance has been dealt with by correcting the imbalance by weighting a specific portion of the rotating body or making a hole to balance the weight. For example, in automobile tires, weights for unbalance correction are used, and even in general motors,
When assembling the motor, a hole is made in a part of the rotor to adjust the imbalance. Even in a grindstone rotating device of an ultra-precision processing machine, unbalance correction called balancing is performed on a grindstone and a rotating body such as a shaft to which the grindstone is attached.

In the case of correcting imbalance, a balancing machine is generally used to attach a rotating body such as a tire or a motor shaft to the balancing machine, and a vibration detection for detecting a vibration built in the balancing machine. Based on the signal from the sensor and the signal of the rotation angle detection sensor that detects the rotation angle, calculate the position and amount of unbalance, and attach a weight corresponding to the amount of unbalance to the position, I am making holes and making corrections.

On the other hand, in the ultra-precision processing machine, it is not possible to take out only the rotating body composed of the grindstone for processing the work and the shaft to which the grindstone is mounted, and mount it on the balancing machine. Therefore, in this case, the vibration detecting sensor and the rotation angle detecting sensor having the same configuration as the balancing machine are attached to the grindstone rotating device of the ultra-precision processing machine. FIG. 3 is a block diagram schematically showing a configuration of a grindstone rotating device of an ultra-precision processing machine and a conventional measuring device for measuring imbalance of a rotating body of the grindstone rotating device. As shown in FIG.
Grinding stone 11, grindstone 1 for processing a workpiece (not shown)
1, a shaft portion 12 for mounting 1, a bearing 13, a motor 14 mounted on the shaft portion 12 for rotating the shaft portion 12 and the grindstone 11, a housing 15 for mounting the motor 14, and a motor for rotating the motor 14. It is composed of a drive unit 16. Further, the measuring device 30 is attached to the bearing 13, and the vibration detection sensor 31 and the shaft portion that detect the vibration applied to the grindstone rotating device 10 by rotating the shaft portion 12 and the grindstone 10 with the rotation of the motor 14. Rotation angle detection sensor 32 provided adjacent to the upper flange 12a of 12 and vibration detection sensor 3
A processing device 33 is provided for measuring the position and the amount of the imbalance of the rotating body based on the signal output from 1 and the signal output from the photo sensor 32. This vibration detection sensor 31 is called a piezoelectric type acceleration pickup, and a weight (not shown) housed therein moves due to the vibration generated in the grindstone rotating device 10, whereby it is fixed to the grindstone rotating device 10. The piezoelectric element provided between the housing (not shown) of the vibration detection sensor 31 and the weight is subjected to shearing force to generate electric charge, and a signal based on this electric charge is output.

When the grindstone rotating device 10 thus constructed is activated, a motor drive signal is given from the motor driving device 16 to the motor 14, and the shaft portion 12 and the grindstone 11 rotate as the motor 14 rotates. To do. Shaft 1
When there is an imbalance in the rotating bodies such as 2 and the grindstone 11, vibration occurs in the grindstone rotating device 10, and thereby a signal is given from the vibration detection sensor 31 to the processing device 33. On the other hand, as the shaft portion 12 and the grindstone 11 rotate, the rotation angle detection sensor 32 outputs signals indicating these rotation angle positions. Therefore, the processing device 33 measures the position where the rotor is unbalanced and the amount thereof based on the signal from the vibration detection sensor 31 and the signal from the rotation angle detection sensor 32.

[0008]

However, in the conventional measuring device for measuring the imbalance of the rotating body of the grindstone rotating device of the ultra-precision processing machine as described above, the vibration to be detected by the vibration detecting sensor of the measuring device. Is the vibration of the entire grindstone rotating device caused by the imbalance of the rotating body, so the amount of vibration that can be detected by the vibration detection sensor is not only the amount of imbalance of the rotating body only, but also the rigidity of the grindstone rotating device. It also depends on Therefore, in the conventional measuring device, even if the unbalance amount of the rotating body is large, if the rigidity of the grindstone rotating device to which the measuring device is attached is high, the vibration generated in the device is not so large, which is a particular problem in the grindstone rotating device. There is a problem that an imbalance of several g or less cannot be detected.

Further, the measuring device attached to the grindstone rotating device is not only necessary but often obstructive when the ultra-precision processing machine actually processes a workpiece, and the measuring device must be detachable. There was a problem that there was. Further, there is a problem that it is necessary to secure a space for accommodating the removed measuring device. Also, by attaching a vibration detection sensor or a rotation angle detection sensor, the vibration characteristics of the grindstone rotating device itself change, so after measuring the imbalance of the rotating body and correcting the imbalance, remove the measuring device. There is also a problem that the vibration state of the grindstone rotating device changes when the workpiece is machined.

It is an object of the present invention to provide an imbalance measuring device for a rotating body, which is capable of surely measuring even a slight imbalance.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating mechanism having a motor, a rotating body rotated by the motor, and a housing for accommodating and mounting the motor. A rotational body imbalance measuring device for measuring an unbalance of a body, comprising: a rotation angle detection means attached to the rotating body, for detecting a rotation angle of the rotating body when the rotating body rotates; and the housing. Mounted on the housing and interposed between the housing and a stable base, the force detecting means for detecting a change in the force applied to the housing by the rotation of the rotating body, and the rotation angle detecting means. Measuring means for measuring the position and the amount of the imbalance based on the rotation angle thus obtained and the fluctuation of the force detected by the force detecting means. It is achieved by the rotation of the unbalance measuring apparatus equipped with a.

In a preferred aspect of the present invention, the force detecting means is composed of a piezoelectric load washer.

[0013]

According to the present invention, the force detecting means for detecting the fluctuation of the force is attached to the housing and is interposed between the housing and the stable base portion. Therefore, regardless of the rigidity of the rotating mechanism of the rotating body. First, the imbalance of the rotating body can be detected, and as a result, even a slight imbalance can be reliably measured.

[0014]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram schematically showing the configuration of a measuring device according to an embodiment of the present invention and a grindstone rotating device of an ultra-precision machine in which the imbalance of a rotating body is measured by the measuring device, and FIG. It is a partial schematic sectional view which shows the rotating mechanism of a measuring device and a grindstone rotating device in detail.

The grindstone rotating device 10 is a work (not shown).
A grindstone 11 for machining a grindstone, a shaft 12 for mounting the grindstone, a bearing 13 mounted on the housing 15, a motor 14 mounted on the shaft 12 for rotating the shaft 12 and the grindstone 11, and a motor 14. A housing 15 for mounting and a motor driving device 16 for rotating the motor 14 are provided. These constituent parts of the grindstone rotating device 10 are the same as those of the grindstone rotating device shown in FIG. Further, the grindstone rotating device 10 has a rotation angle detection sensor 17 near the motor shaft of the motor 14 for detecting the rotation angle of the motor 14 and giving a signal corresponding to the detected rotation angle to the motor drive device 16. ing.

On the other hand, the measuring device 20 comprises the housing 1
5 and a stable base 21 for installing the grindstone rotating device 10, for example, a force detection sensor 22, a rotation angle detection sensor 17, and a force detection sensor 22 that are interposed between the ground surface.
And processing means 2 for measuring the position and amount of unbalance generated in the rotating body based on signals from these.
3 and a display device 24 connected to the processing means 23 and capable of displaying the position and amount of imbalance measured by the device.

As shown in more detail in FIG.
Is a cylindrical body 11a that processes the work by its outer periphery contacting a work (not shown), a grindstone shaft 11b, and a cylindrical grindstone flange that functions as a correction plate for correcting imbalance. 11c. The shaft portion 12 includes an upper flange 12a firmly connected to the grindstone flange 11c and a lower flange 12b firmly connected to the motor shaft 14a of the motor 14.
And an intermediate portion 12c surrounded by the bearing 13.

The bearing 13 fixed to the housing 15 is provided with a large number of holes (not shown), and pressurized air is supplied from an air source (not shown) to the bearing 13
An air bearing is formed between the inner peripheral surface of the shaft and the intermediate portion 12c of the shaft portion 12.

The motor 14 is provided with a motor shaft 14a including a shaft flange 14b connected to the lower flange 12b, a rotor 14c attached at a predetermined position on the outer periphery of the motor shaft 14a, and a rotor 14c so as to face the rotor 14c. And a motor casing 14f for mounting the stator 14d and rotatably supporting the lower end portion 14e of the motor shaft 14a. The motor casing 14f is fixed to the housing 15. Further, the lower end portion 14e of the motor shaft 14a projects downward and terminates inside the rotation angle detection sensor 17, which will be described in detail later. In this embodiment, the motor shaft 14a
Also constitutes a part of the rotating body.

In the grindstone rotating device 10 of this embodiment,
Four legs 18 are provided on the bottom of the housing 15 at angular intervals of 90 degrees, and one of them is provided with a force detection sensor 21. The housing 15 is fixed to the legs 18 by a suitable attachment (not shown),
Further, the leg portion 18 is fixed to the stable base portion 21. That is, the housing 15, the legs 18, and the stable base 21 are configured so as not to move relative to each other.

The rotation angle detecting sensor 17 is attached to a lower portion of the motor casing 14f, and has a lower end portion 14e of the motor shaft 14a, a rotary encoder (not shown) rotatable with the rotation of the motor shaft 14a, and a light emitting element. And a light receiving element (both not shown).

As described above, the force detecting sensor 22 provided on one of the four leg portions 18 is composed of a piezoelectric load washer in this embodiment, and the grindstone rotating device 1
An electric charge is generated by a change in a certain unidirectional force applied to one of the legs 18 by the vibration generated at 0. In addition, when the ultra-precision processing machine is processing a workpiece, the output signal of the force detection sensor 22 is given to a computer (not shown) or the like to detect fluctuations in the processing force of the ultra-precision processing machine. Can be used for

The measurement of the unbalance of the rotating body by using the grindstone rotating device 10 and the measuring device 20 thus constructed will be described below.

When the operator starts the motor drive device 16, a motor drive signal is given from the motor drive device 16 to the motor 14. When the motor 14 rotates, the shaft portion 12 and the grindstone 11 rotate as the motor shaft 14a rotates. Since the rotary encoder (not shown) of the rotation angle detection sensor 17 provided at the lower end portion 14e of the motor shaft 14a is provided with slits (not shown) at predetermined intervals, the rotation of the motor 14 is accompanied. The light emitted from the light emitting element (not shown) by the rotation of the rotary encoder passes through the slit and is received by the light receiving element, or is reflected by the portion of the encoder where the slit is not formed. Therefore, a signal composed of pulses at predetermined intervals is generated based on the light received by the light receiving element, and this signal is output from the rotation angle detection sensor 17.

The signal output from the rotation angle detection sensor 17 is given to the motor drive device 16. The motor drive device 16 determines the number of rotations of the motor based on the given signal and outputs an appropriate motor drive signal to the motor 14.

The grindstone 11, the shaft portion 12 and the motor shaft 14a
If there is an unbalance in the rotating body, the unbalance causes vibration of the grindstone rotating device 10 during rotation of the rotating body, and this vibration causes the housing 1 of the grindstone rotating device 10 to vibrate.
The force applied to the leg 18 fixed to the 5 and the stable base 21 varies. Therefore, the force detection sensor 22 provided on one of the four legs 18 outputs a signal based on the fluctuation of the force to the processing device 23. The force applied to the leg portion 18 does not depend on the rigidity of the housing 15 of the grindstone rotating device 10 or the like.

On the other hand, the signal output from the rotation angle detection sensor 17 is also given to the processing device 23. Therefore, the processing device 23 determines, based on the signal output from the rotation angle detection sensor 17 and the signal output from the force detection sensor 22, the angular position and the amount of the change in force, that is, the rotational body. The position and amount of the imbalance are measured, and these are displayed on the display device 24 connected to the processing device 23.

Based on the angular position and the amount of fluctuation displayed on the display device 24, the operator sets a predetermined size in the portion of the grindstone flange 11c of the grindstone 11 corresponding to the position where the imbalance occurs. Make a hole, or in this part,
By attaching the additional weight, the imbalance of the rotating body can be corrected.

According to this embodiment, the rotation angle detection sensor 17
Of the force from a signal from the wheel rotating device 10 and one of the four legs 18 fixed to the housing 15 of the grinding wheel rotating device 10 and the stable base 21 and caused by a small vibration generated in the wheel rotating device 10. Based on the signal from the force detection sensor 22 capable of detecting even a small amount of imbalance, the processing device 23 is configured to measure the position and amount of the imbalance of the rotating body, so that a slight imbalance occurs. Can be measured reliably.

Further, according to this embodiment, the rotation angle detecting sensor 17 is attached to the motor casing 14f of the motor 14, and the force detecting sensor 22 is fixed to the housing 15 of the grindstone rotating device 10 and the stable base 21. Since it is provided on one of the four legs 18
Even when the grindstone rotating device 10 is actually used for processing a work, the convenience can be prevented from being impaired.

Further, according to this embodiment, the output signal of the rotation angle detection sensor 17 is output by the motor drive device 16 to the motor 1.
4 can be used to measure the rotation speed, and
The output signal of the force detection sensor 22 can also be used to detect fluctuations in the processing force of the ultra-precision processing machine when the grindstone rotating device 10 is used to process a workpiece. Therefore, it becomes possible to measure the imbalance of the rotating body without attaching a separate sensor to the grindstone rotating device 10 itself of the ultra-precision processing machine.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is one.

For example, in the above-described embodiment, the force detection sensor 22 is provided on one of the four leg portions 18 fixed to the housing 15 and the stable base portion 21. 22 is provided such that one side thereof is fixed to a predetermined position of the side wall of the housing 15 and the other side is fixed to a stable base portion that is substantially upright from the ground surface such as a pillar of a building. The force detection sensor 22 and the stable base portion may be configured not to move relative to each other.

Further, in the above embodiment, the force detection sensor 22 is configured to detect a change in force in one direction, but the present invention is not limited to this. Detect the horizontal and vertical components of
Obviously, it may be configured to output a signal corresponding to each. In this case, it is necessary to provide a correction plate for correcting the imbalance of the horizontal component and a correction plate for correcting the imbalance of the vertical component.

[0035]

According to the present invention, it is possible to provide an imbalance measuring device for a rotating body, which is capable of reliably measuring even a slight imbalance.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of a measuring device according to an embodiment of the present invention and a grindstone rotating device of an ultra-precision processing machine in which an imbalance of a rotating body is measured by the measuring device. is there.

FIG. 2 is a partial schematic cross-sectional view showing in more detail the rotating mechanism of the measuring device and the grindstone rotating device.

FIG. 3 is a block diagram schematically showing a configuration of a grindstone rotating device of an ultra-precision processing machine and a conventional measuring device for measuring imbalance of a rotating body of the grindstone rotating device.

[Explanation of symbols]

 10 Grinding Wheel Rotating Device 12 Shaft Part 13 Bearing 14 Motor 15 Housing 16 Motor Driving Device 17 Rotation Angle Detection Sensor 20 Measuring Device 21 Stable Base 22 Force Detection Sensor 23 Processing Device

Claims (2)

[Claims] 1. A rotating body for measuring an imbalance of the rotating body in a rotating mechanism having a motor, a rotating body rotated by the motor, and a housing for accommodating the motor and mounting the motor. An unbalance measuring device, which is attached to the rotating body, detects rotation angle of the rotating body when the rotating body rotates, and rotation angle detecting means, which is attached to the housing and stable with the housing. A force detecting unit that is interposed between the rotary unit and a base unit to detect a change in the force applied to the housing when the rotating body rotates, and the rotation angle and the force detecting unit detected by the rotation angle detecting unit. A rotation comprising: a position where the imbalance occurs and a measuring unit that measures the amount of the imbalance based on the fluctuation of the force detected by the rotation. Unbalance measuring device. 2. The unbalance measuring device for a rotating body according to claim 1, wherein the force detecting means is composed of a piezoelectric load washer.