JPH0631622A - Balance correcting device - Google Patents

Abstract

PURPOSE:To quickly correct the unbalance of a rotor and make a correcting device compact. CONSTITUTION:A balance correcting device is provided with ultrasonic motors 15a, 15b generating traveling waves on stators 24a, 24b around the axis of a rotor 6 via the vibration of piezoelectric elements 26a, 26b to rotate rotors 27a, 27b, and the rotors 27a, 27b are provided with unbalance adjustment sections 31a, 31b for correcting the unbalance of the rotor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance correction device for correcting unbalance of a rotating body.

[0002]

2. Description of the Related Art Conventionally, as a technique of this kind, in order to automatically correct an unbalance of a grindstone, a liquid injection nozzle connected to a pressure pump is arranged to face a pocket provided around an axis of a mounting flange of the grindstone. To do. A liquid balance correction device has been proposed which corrects the unbalance of the grindstone by selectively injecting the liquid ejected from the liquid ejection nozzle into a plurality of pockets.

However, in the liquid type balance correction device, there is a limit to the followability of the liquid injection, and due to this limit, the rotational speed of the grindstone is several 1000 rpm to a maximum of 1000.
There is a problem that it is limited to 0 rpm.

Further, when the rotation of the grindstone is stopped, the liquid flows down from the pocket, and the balance state is lost. Therefore, there is a problem that the imbalance of the grindstone must be corrected every time the grindstone is rotated.

Further, since the liquid jet nozzle is arranged so as to face the grindstone, there is a problem that the balance correction device becomes large in size. As a countermeasure against this, there has been proposed a balance correction device in which a balance correction member is provided on a mounting flange of a grindstone and a part of the balance correction member is removed to correct the unbalance of the grindstone.

[0006]

However, in this balance correction device, not only is it necessary to provide a balance correction member for removing on the grindstone flange side, but also a removal device for removing this balance correction member is provided outside. There is a problem in that the device itself must be provided and the device itself becomes large.

The present invention has been made to solve the above problems, and an object thereof is to provide a balance correction device capable of quickly correcting the imbalance of a rotating body and achieving compactness. Especially.

[0008]

In order to solve the above problems, in the first invention, a traveling wave is generated in the stator by the vibration of the piezoelectric element about the axis of the rotating body,
The gist of the invention is to provide an ultrasonic motor for rotating the rotor by the traveling wave and to provide the rotor with an unbalance adjusting unit for correcting the unbalance of the rotating body.

According to a second aspect of the present invention, there are provided a vibration detector for detecting vibration including vibration of the rotating body, an origin detecting sensor for detecting an origin of the rotating body, a detection signal of the vibration detector and an origin detecting sensor. Calculation control means for calculating an unbalance angle and an unbalance amount of the vibration based on an origin signal, and signal transmission means for transmitting the unbalance angle and the unbalance amount obtained by the calculation control means as a command signal, Signal receiving means for receiving a command signal from the signal transmitting means, and rotation control of the rotor of the ultrasonic motor based on the command signal received by the signal receiving means, and an imbalance adjusting section provided on the rotor. The gist of the present invention is to provide a rotation control means for rotating and moving the to correct the balance of the rotating body.

[0010]

Therefore, according to the first aspect of the invention, the traveling wave is generated in the stator of the ultrasonic motor by the vibration of the piezoelectric element, and the rotor is rotated. Then, the unbalance of the rotating body is corrected by rotationally driving the unbalance adjusting unit provided on the rotor to an angle for correcting the unbalance.

According to the second invention, when the rotating body rotates, the vibration detector detects the vibration including the vibration of the rotating body and outputs the vibration detection signal to the arithmetic control means. Further, the origin detection sensor detects the origin and outputs an origin signal to the arithmetic control means. Then, the calculation control means calculates the unbalance angle and the unbalance amount based on the vibration detection signal and the origin signal. Further, the unbalance angle and the unbalance amount obtained by the arithmetic control means are transmitted from the signal transmitting means to the signal receiving means as command signals. The command signal received by the signal receiving means is output to the rotation control means.

At this time, the rotation control means controls the rotation of the rotor of the ultrasonic motor based on the command signal to rotationally move the unbalance adjusting section provided on the rotor to correct the balance of the rotating body.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a balance correction device for a grinding machine will be described below with reference to FIGS.

As shown in FIG. 1, a holder 2 is fixed to a main shaft 1 of a column head H of a grinding machine by a nut 3. A flange 5 is attached and fixed to the holder 2 with a screw 4. And this flange 5
A grindstone 6 is sandwiched and fixed between the holder 2 and the holder 2.

A vibration detector 7 is attached to the upper part of the column head H so as to detect the vibration generated in the entire grinding machine including the vibration of the grindstone 6. Further, an origin detection sensor 8 is provided on the base end side of the spindle 1 of the column head H, and the origin of the grindstone 6 is detected by detecting the magnetism of the magnet 8a attached to the spindle 1, and the grindstone is also detected. The number of rotations of 6 is detected. The vibration detector 7 and the origin detection sensor 8 are connected to an external control circuit 9 and are configured to output respective detection signals to the external control circuit 9. A light emitting element 10 as a signal transmitting means is attached to the side surface of the external control circuit 9 on the side of the grindstone 6 on the central axis of the spindle 1.

A balance correction device 11 for correcting the unbalance of the grindstone 6 is fixed to the front surface of the flange 5 with a bolt 12. This balance correction device 11
Is attached on the basis of the center of rotation of the spindle 1, so that the grindstone 6 can be smoothly rotated.

The structure of the balance correction device 11 will be described in detail below. In this automatic balance adjusting device 11, a through hole 13a is formed near the center of the front surface of the case 13.
Inside the balance correction device 11, the through hole 1
The light receiving element 14 as a signal receiving means is attached so as to coincide with 3a.

Further, the case 13 of the balance correction device 11
Inside, a first ultrasonic motor 15a and a second ultrasonic motor 15b having the same structure are arranged side by side coaxially with the main shaft 1.

Since the first ultrasonic motor 15a and the second ultrasonic motor 15b have the same structure, the first ultrasonic motor 15a and the second ultrasonic motor 15b are used. In the description of the structure of 1), for convenience of description, the structure relating to the first ultrasonic motor 15a will be described by adding a subscript a to the number. The structure of the second ultrasonic motor 15b is replaced by adding a subscript b to the number of the structure corresponding to that of the first ultrasonic motor 15a, and description will be appropriately added as necessary.

As shown in FIG. 4, the first ultrasonic motor 1
A base 17a is fixed in the main body case 16a that constitutes 5a, and a storage space 18a is formed by the base 17a and the case 16a. The base 17
A mounting portion 19a is formed on the inner surface of the center of a, and
A storage recess 20a is provided on the lower surface of the center of the base 17a. An insertion hole 21 is formed at the center of the base 17a.
a is formed, and the tip of the rotary shaft 22a is inserted into the storage space 18a through the insertion hole 21a. Also,
The rotating shaft 22a is rotatably supported by a bearing 23a arranged in the storage recess 20a. The rotary shaft 22a is fixed to the inner ring of the bearing 23a.

A stator 24a is fixedly mounted on the mounting portion 19a of the base 17a. That is, the stator 2
A through hole 25a is formed in the center of 4a, and
The protrusion formed to project on a is inserted and fixed in the through hole 25a. A pair of semi-circular piezoelectric elements 26a is attached to the bottom surface of the stator 24a.

A high-frequency voltage having a phase difference of 90 deg is applied to the pair of piezoelectric elements 26a by a drive circuit 33 described later. Therefore, the pair of piezoelectric elements 26a expands and contracts, and a traveling wave traveling in one direction is generated on the surface of the stator 24a.

A rotor 27 is provided on the upper surface of the stator 24a.
a is placed. An insertion hole 28a is transparently provided at the center of the rotor 27a, and the rotary shaft 22a is inserted through the insertion hole 28a. The tip of the rotary shaft 22a is in a state of protruding above the rotor 27a.

An elastic member 29a is placed on the upper surface of the rotor 27a, and the elastic member 29a is mounted on the rotary shaft 22.
The rotor 27a is pressed downward by a nut 30a that is screwed into the male screw 22a formed at the tip of a. Therefore, the rotor 27a is placed in pressure contact with the upper surface of the stator 24a. When a high frequency voltage having a phase difference of 90 deg is applied to the pair of piezoelectric elements 26a by the drive circuit 33, a traveling wave traveling in one direction is generated on the surface of the stator 24a. Therefore, the rotor 27a is rotated by the traveling wave in the direction opposite to the traveling wave. still,
The rotor 27 is generated by the traveling wave generated in the stator 24a.
Each a can be rotated in the same direction or can be rotated in a relative direction.

Further, on the outer peripheral edge of the rotor 27a,
A weight 31a having a mass m as an imbalance adjusting unit is fixed. Then, the weight 31a is attached to the rotor 27.
a while rotating the second ultrasonic motor 15
Also in b, the unbalance of the grindstone 6 is corrected by rotating the weight 31b having the same mass m by the rotor 27b. As shown in FIG. Control circuit 3 for first ultrasonic motor 15a and second ultrasonic motor 15b
2, the drive circuit 33 and the drive source 34 are attached.
It should be noted that this balance correction device 11 has the weights 31a, 31
Any imbalance other than b will not occur.

Next, the electrical configuration of the balance correction device 11 will be described with reference to FIG. FIG. 3 shows an electric block diagram of the balance correction device 11. The vibration detector 7 detects the vibration generated in the entire grinding machine and outputs the vibration detection signal S to the external control circuit 9. ing. The origin detection sensor 8 detects the magnetism of the magnet 8a attached to the spindle 1, detects the rotation speed of the grindstone 6, and outputs the origin signal Q that detects the origin mark 8a to the external control circuit 9. Has become.

As shown in FIG. 6, the vibration detection signal S is generally a sine wave or a waveform approximated to a sine wave, and the origin signal Q indicates the origin for the vibration detection signal S.

Then, the external control circuit 9 obtains the time from the output of the origin signal Q to the maximum value of the vibration detection signal S based on the vibration detection signal S and the origin signal Q, From that time, the angle (unbalance angle) α ° with respect to the magnet 8a is calculated, and the maximum value (unbalance amount) u of the vibration detection signal S is calculated.

Further, the external control circuit 9 encodes the unbalance angle α ° and the unbalance amount u as command signals. The encoded command signal is transmitted by the light emitting element 10 to the light receiving element 14 of the balance correction device 11.
Sent to.

Based on the command signal transmitted to the light receiving element 14, the control circuit 32 determines the unbalance angle α ° of the entire grinding machine, the unbalance amount u, and the unbalance vector U of the entire grinding machine. . Further, the control circuit 32 is adapted to obtain a weight imbalance vector V generated by the mass m of the weights 31a and 31b. Then, the control circuit 32 obtains the unbalance vector U1 of the grindstone 6 based on the unbalance vector U and the weight unbalance vector V of the entire grinding machine, and calculates the unbalance angle α1 ° of the grindstone 6 and the unbalance amount u1. I am asking for it.

Since the control circuit 32 cancels the unbalance vector U1 of the grindstone 6, the unbalance angle α1 °.
And the weights 31a and 31b based on the unbalance amount u1
It is designed to calculate how much to rotate.
The result calculated by the control circuit 32 is output to the drive circuit 33 as a rotation command signal.

The drive circuit 33 applies a high frequency voltage to the piezoelectric elements 26a and 26b in the ultrasonic motors 15a and 15b based on the rotation command signal from the control circuit 32, and the rotor 27 is rotated.
The weights 31a and 31b are rotationally moved by rotating a and 27b. Then, the unbalance U1 of the grindstone 6 is offset to correct the rotation of the grindstone 6.

Next, the operation and effect of the balance adjusting device 11 configured as described above will be described. First,
As shown in FIG. 1, when the spindle 1 is rotated and the grindstone 6 is rotated, the vibration detector 7 detects the vibration of the entire grinding machine and outputs it as a vibration detection signal S to the external control circuit 9. Further, the origin detection sensor 8 outputs the origin detection signal Q to the external control circuit 9 by detecting the magnet 8a. Then, the external control circuit 9 determines the unbalance angle α of the entire grinding machine based on the vibration detection signal S and the origin detection signal Q.
And the unbalance amount u are calculated.

Further, as shown in FIG. 6, the unbalance angle α ° and the unbalance amount u are coded in the external control circuit 9, and the coded command signal is used as the light emitting element 1.
It is sent from 0.

The command signal transmitted from the light emitting element 10 is received by the light receiving element 14 and output to the control circuit 32. Then, the control circuit 32 obtains the unbalance angle α °, the unbalance amount u, and the unbalance vector U of the entire grinder based on the coded command signal.

For example, in the state shown in FIGS. 5A and 5B, the control circuit 32 obtains the unbalance vector U of the entire grinding machine based on the unbalance angle α ° and the unbalance amount u, and the weight 31a. , 31b to obtain the weight imbalance vector V. Here, the unbalance vector U of the grinder mainly comprises a grindstone unbalance vector U1 of the grindstone 6 and a weight unbalance vector U. Therefore, the control circuit 32 obtains the grindstone unbalance vector U1 by subtracting the weight unbalance vector V from the unbalance vector U, and also obtains the unbalance amount u1 and the unbalance angle α1 °.

The control circuit 32 uses the unbalance vector U
1. Calculate how much the weights 31a, 31b of the rotors 27a, 27b should be rotationally moved based on the unbalance amount u1 and the unbalance angle α1, and output the calculation result to the drive circuit 33 as a rotation command signal. To do.

The drive circuit 33 applies a high frequency voltage to the piezoelectric elements 26a and 26b of the ultrasonic motors 15a and 15b based on the rotation command signal of the control circuit 32, and the rotor 27 is rotated.
The weights 31a and 31b are rotationally moved by rotating a and 27b. Then, the unbalance vector U1 of the grindstone 6 is offset by the weight unbalance vector V. As a result, the imbalance of the grindstone 6 can be corrected.

Therefore, by using the ultrasonic motors 15a and 15b in which the unbalance adjusting weights 31a and 31b are attached to the rotors 27a and 27b, the mechanism for adjusting the unbalance of the grindstone 6 is simplified, The device itself can be made compact.

In general, the ultrasonic motor is a friction drive type actuator, and the rotor can be held at that position even when the power is cut off. Therefore, even if the rotation of the grindstone 6 is stopped, the weights 31a and 31b do not move. Therefore, it is not necessary to correct the unbalance of the grindstone 6 every time the grinding machine is started. Moreover, since it is sufficient to drive the first ultrasonic motor 15a and the second ultrasonic motor 15b only when it is desired to rotationally drive the weights 31a and 31b, it is possible to achieve low power consumption.

The present invention is not limited to the above-described embodiments, but can be implemented as follows with appropriate modification of a part of the configuration without departing from the spirit of the invention. (1) In the above embodiment, two ultrasonic motors are used, but one ultrasonic motor may be used.
In this case, the unbalance amount of the grindstone 6 is constant, and the same amount of weight as the unbalance amount is fixed to the ultrasonic motor.

(2) In the above embodiment, the rotors 27a, 2a
7b includes weights 31a and 31 as unbalance adjustment masses.
Although b is fixed, a new rotary plate may be fixed to each of the rotors 27a and 27b, and weights for mass adjustment may be fixed to those rotary plates.

(3) In the above embodiment, the weights 31a and 31b as the unbalance adjusting mass are attached to the rotors 27a and 27b.
The rotors 32a, 3b are fixed to the rotors 32a, 3b by forming holes in the rotors 27a, 27b or by making the rotors 27a, 27b eccentric with respect to the rotating shafts 22a, 22b.
A mass difference may be provided in 2b, and the imbalance may be adjusted by this mass difference.

(4) In the above embodiment, light communication is performed using the light emitting element 10 and the light receiving element 14, but the wireless method is not particularly limited, and, for example,
It may be transmitted by radio waves.

(5) In the above embodiment, the weights 31a, 31
b had the same mass m, but the weights 31a, 3
The masses of 1b need not be the same.

[0046]

As described in detail above, according to the present invention, there is an excellent effect that the imbalance of the rotating body can be quickly corrected and the size can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a state in which a balance correction device is fixed to a rotating body of a grinding machine in one embodiment showing the present invention.

FIG. 2 is a schematic plan sectional view showing the structure of the balance correction device in one embodiment.

FIG. 3 is an electrical block diagram of a balance correction device in one embodiment.

FIG. 4 is a sectional view showing a schematic configuration of an ultrasonic motor in one embodiment.

FIG. 5A is an explanatory diagram showing a weight fixed to a rotor and an unbalanced state at that time in one embodiment, and FIG. 5B is a vector diagram showing each vector.

FIG. 6 is a diagram showing a vibration detection signal and an origin signal in one embodiment.

[Explanation of symbols]

6 ... Grinding stone as rotating body, 7 ... Vibration detector, 9 ... External control circuit as arithmetic and control unit, 10 ... Light emitting element as signal transmitting means, 14 ... Light receiving element as signal receiving means, 1
5a, 15b ... Ultrasonic motor, 24a, 24b ... Stator, 26a, 26b ... Piezoelectric element, 27a, 27b ... Rotor, 31a, 31b ... Weight as imbalance adjusting section, 32 ... Control circuit as rotation control means, 33 ... Drive circuit as rotation control means, S ... Detection signal, α ... Unbalance angle, u ... Unbalance amount.

Claims (2)

[Claims] 1. A stator (24) is provided around the axis of a rotating body (6) by vibration of piezoelectric elements (26a, 26b).
a, 24b) to generate a traveling wave and the rotor (27a, 27b) is rotated by the traveling wave.
5a, 15b), and the rotor (27a, 27b)
The balance correction device is characterized in that an unbalance adjustment unit (31a, 31b) for correcting the unbalance of the rotating body (6) is provided in the. 2. A vibration detector (7) for detecting a vibration including a vibration caused by an imbalance of the rotating body (6), and an origin detecting sensor (8) for detecting an origin of the rotating body (6). An unbalance angle (α °) and an unbalance amount (u) of the vibration are calculated based on the detection signal (S) of the vibration detector (7) and the origin signal (Q) of the origin detection sensor (8). Arithmetic control means (9), signal transmitting means (10) for transmitting the unbalance angle (α °) and the unbalance amount (u) obtained by the arithmetic control means (9) as a command signal, and the signal transmission Signal receiving means (14) for receiving a command signal from the means (10), and rotors (27) of the ultrasonic motors (15a), (15b) based on the command signal received by the signal receiving means (14).
a) and (27b) are rotationally controlled so that the rotor (27a,
27b), an unbalance adjustment unit (31a),
A balance correction device comprising: rotation control means (32, 33) for rotationally moving (31b) to correct the balance of the rotating body (6).