JPS6082072A - Stepping motor - Google Patents

Abstract

PURPOSE:To enable to reduce the size and a stepping angle of a stepping motor by providing a plurality of piezoelectric elements at the periphery of a shaft, controlling the elements, providing means for driving any of the elements in a tangential direction and controlling it. CONSTITUTION:A rotational shaft 12 is rotatably supported by bearings 13, 14 provided at the center of a motor vessel 10 and a flange 11. Rotation transmitting means 17 formed of piezoelectric elements are provided at the periphery of a rotational shaft 12, and formed in a cylindrical shape. Electrodes 19, 20 of thin film state are provided on the inner and outer peripheries of the means 17. Rotary drive means 24 are contacted with a moving member 23. Rotating preventing means 18 is provided at the periphery of the shaft 12. A control voltage is applied to the means 17, 18, 24 synchronously with a clock pulse to rotate the shaft 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel stepping motor using a piezoelectric element used in electronic equipment and the like.

[Prior Art] Stepping motors, which are generally referred to as precision motors, are easy to position using digital control, and are therefore being used in various fields with the recent development of digital control technology. A conventional stepping motor like this consists of a stator with multiple teeth formed on the inner periphery and a gear-shaped rotor with multiple teeth formed on the outer periphery and a built-in permanent magnet.
By exciting the coil wound around the stator, J is set such that a rotation angle (step angle) is generated on the rotating shaft.
has been completed.

Therefore, if the conventional stepping motor J3 configured in this way is to be replaced in order to reduce the rotation angle for each step, the number of teeth formed on the stator and then on the rotor will be reduced. A method is used to form as many as possible. However, since there are limits to mechanical microfabrication, there is a drawback that the volume of the stepping motor becomes larger when the rotation angle is reduced.

[Object of the Invention] The present invention provides a compact stepping motor with a small step angle, which eliminates the disadvantages of conventional devices.
The purpose is to

[Structure of the Invention] The present invention relates to a stepping motor used in electronic equipment, etc., which is composed of a rotating shaft and a piezoelectric element, and the rotation of the rotating shaft is prevented or enabled by controlling the voltage applied to the piezoelectric element. a rotation preventing means for switching; a rotation transmitting means comprising a piezoelectric element and switching between a state of being fixed to the rotating shaft and a state of releasing the fixing to the rotating shaft by controlling the voltage applied to the piezoelectric element; A rotational drive means for rotating the transmission means, and a rotational drive power supply for controlling the rotation of the rotating shaft by applying electricity to each of the rotation stopper stage rotation transmission means and the rotational drive means. It is characterized by

[Principle of the Invention] As shown in FIG. 1, the present invention comprises sandwiching both sides of, for example, a crystal piece as a piezoelectric element 1 formed with an appropriate thickness between electrodes 2 and 3 made of metal plates, voltage [switch S
When turned on and applied, the piezoelectric element 1 having the thickness t shown by the solid line shrinks into the piezoelectric element 1' having the thickness t' shown by the broken line in FIG. Further, the shrunk piezoelectric element 1' (shown by the broken line) returns to its original thickness t (shown by the solid line) when the switch S is turned off and the application of the voltage is stopped. The present invention uses minute piezoelectric elements to mechanically move the electric signal 8 with a fast response speed.
This was done by taking advantage of the property that it can be converted into

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing one embodiment of the present invention;
The figure is an A-A sectional view of the embodiment shown in Fig. 2, and Fig. 4 is a cross-sectional view of the embodiment shown in Fig. 2.
It is a B-BrM plane view of the example shown in the figure. In the figure,
Reference numeral 10 denotes a cylindrical container at the right bottom of the stepping motor, and a flange 11 is provided at the opening of the motor container 1o. 12 is a rotating shaft, and the rotating shaft 12 is rotatably supported by bearings 13 and 14 provided at the center of the motor container 1o and the flange 11. 15
and 16 are rings for preventing movement of the beams 11 and holders 13 and 14 in the axial direction. Reference numeral 17 denotes a rotation transmitting means that is provided around the rotating shaft 12 and is composed of a piezoelectric element formed in a cylindrical shape. Thin film electrodes 19 and 20 are provided on the inner and outer peripheries of the rotation transmitting means 17, and the portion of the rotating shaft 12 in contact with the electrodes 19 is insulated. A high voltage is periodically applied between the respective electrodes from the rotational drive power source E. Therefore, as shown in FIG. 5(a), for example, when the high voltage from the power source E is not applied when the switch S is off, the rotation transmitting means 17 and the rotating shaft (not shown in the figure) are connected to each other. 1
2, a minute gap is formed between them, and the rotating shaft 12 is in a released state. Furthermore, when the voltage applied to the electrodes 19 and 20 is turned on, the inner diameter of the rotation transmission means 17 uniformly decreases in the direction of the arrow as shown in FIG. 5(b), and the rotation transmission The minute gap formed between the means 17 and the rotating shaft 12 disappears, and the device is fixed to the rotating shaft 12. Reference numeral 18 denotes a rotation preventing means provided around the rotating shaft 12 with a minute gap, and the rotation preventing means 18 is shown in FIG.
As shown in b), it has a ring-shaped shape 1, which is used to uniformly press the outer circumference of the rotating shaft 12 and fix it when the rotation preventing means 18 contracts and fixes the rotating shaft 12. This rotational closing means 18 is attached to the motor container 10 by a support shaft 27a.

27b. Moreover, the rotation closing means 18
Thin-film electrodes 21 and 22 are provided on the inner and outer peripheries of the electrode, and the electrodes 21 and 22 are formed in such a way that a periodic high voltage is not applied to the electrodes 21 and 22 from a power source E (not shown in FIG. 4). ing. Therefore, by turning on and off the high voltage applied from the power source E, the rotation transmitting means 17
Similarly, the rotating shaft 12 is released or fixed. 2
3 is a moving member fixed to the outer periphery of the rotation transmitting means 17. 24, one side is in contact with the moving member 23 and the other side is -E-
The rotary drive means 24 (consisting of a rod-shaped piezoelectric element) is fixed to the container 10 via an insulator 25, and a high voltage from the power supply is applied to the electrodes at both ends of the rotary drive means 24. Then, the rotational drive means 24 is tangentially contracted (
Alternatively, the elastic force of the spring 26 causes the moving member 23 to move by the amount that the rotary drive means 24 has contracted. Therefore, at this time, if a high voltage is applied to the rotation transmission means 17 provided around the rotation shaft 12 and the rotation transmission means 17 is fixed to the rotation shaft 12, the rotation transmission means 17 becomes integral with the rotation shaft 12. and rotate clockwise by Δθ°. Next, when rotating the rotation transmitting means 17 in the opposite direction by 1 Δθ° and returning it to the original position, first the rotation transmitting means 17
Turn off the voltage applied to the rotation transmission means 17 to release the fixation to the rotation shaft 12, and in this state, the rotation drive means 2
Turn off the high voltage applied to 4. As a result, the rotation drive 24 expands and returns to its original state, and the rotation transmission means 17
rotates by 1 Δθ°, but this rotation is not transmitted to the rotating shaft 12, and the rotating shaft 12 can maintain its state of being rotated by Δθ°. In order to completely prevent the rotation of the rotating shaft 12, it is necessary to fix the rotating shaft 12 to the motor container 10 by using the rotation preventing means 18 described above.

The case where the rotating shaft 12 is rotated in the device configured in this way will be explained with reference to FIGS. 5(a) and 5(b).

Here, when rotating the rotating shaft 12 in the direction shown by arrow A in FIG. 3 (clockwise rotation direction), as shown in FIG.
, P3 are applied to the rotation transmitting means 171, the rotation blocking means 181, and the rotation driving means 24. Until the rotation start signal is applied to the power source E at time t1, P2 for preventing rotation of the rotating shaft 12 is kept in the on state, and the rotation preventing means 18 is in a contracted state. At time t1, the waveform of Pl turns on and rotation transmission 1
Means 17 are fixed to the rotating shaft 12. Thereafter, the voltage at P2 is turned off and the rotating shaft 12 is opened. P2
After P3 is turned off, the voltage of P3 is turned on and the rotational drive means 24 is contracted. When the rotary drive means 24 is reduced,
The moving part fixed to the rotation transmitting means 17 (the 23rd is the part that the rotation driving means 24 is compressed by being pressed by the spring 26) moves, and the rotation transmitting means 17 fixed to the moving part vU23 is The rotating shaft 12 fixed to the rotation transmitting means 17 also rotates by △0 in the clockwise direction.
Rotate by °. After P3 is turned on, P2 is turned off.'
Ru. In addition to this, a rotation preventing means 18 fixes the rotating shaft 12. When P2 is turned on and IC and Pl are turned off, a minute gap is formed between the rotating shaft 12 and the rotation driving means 17, and the rotation transmitting means 17 releases the rotating shaft 12. Here, when P3 is referred to as an OFF state, the rotational drive means 24 in contact with the moving member 23 returns to its original state, that is, expands against the pressing force of the spring 26 by the contracted amount, and therefore the rotational transmission means 17 Becomes the initial state. The time is defined as (2. One step operation is completed at this t1~1lz(Δti, and this is repeated as △(1, △t2. △(3... △tn), etc.) 12 t; Continue one rotation.

When rotating in the direction of the arrow in Fig. 3 (counterclockwise), reverse the voltage waveform of P3 and apply the voltages of P+, P2, and P3 according to the timing chart shown in Fig. 6(b). The rotating shaft 12 rotates counterclockwise. Therefore, the one-time step angle of the rotating shaft 12 at this time depends on the moving distance of the moving member 23. Therefore, by shifting the contraction or expansion of P3 that comes into contact with the moving member 23 by -C control depending on the applied voltage value, it is possible to control the single step angle of the rotating shaft 12. .

Furthermore, the axial torque of the rotating shaft 12 can be increased by increasing the shaft diameter of the portion of the rotating shaft 12 that passes through the rotation transmitting means 17.

Incidentally, the present invention is not limited to the above embodiments, and various modifications are possible. In this embodiment, a ring-shaped rotation transmission means 17 and a rotation prevention means 18 are provided around the rotation shaft 12. For example, the rotation prevention means 18 is provided with an insulator 2 as shown in FIG.
It is divided into four parts like 18a, 18b, 18c, and 18d through 8, and is provided with electrodes 21a, 22 respectively.
It may be provided as in a. Further, although the rotational drive means 24 is formed of a piezoelectric element, the rotational drive means 24 can be formed by an air cylinder, an oil cylinder, etc. that drives the rotational drive means in a vertical direction.
A similar effect can be obtained by controlling the amount of water produced.

[Effects] As described above, the present invention provides a stepping motor that is controlled by a digital signal, in which a plurality of piezoelectric elements are provided around the shaft body for controlling the length, and any one of the piezoelectric elements provided around the shaft body. By controlling the motor in the tangential direction, there is no need to form multiple teeth on the inner and outer peripheries like in conventional stepping motors, and the minute expansion and contraction characteristics of the piezoelectric element can be controlled. The present invention provides a small and novel stepping motor with a small step angle because of its application.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the operating principle of a piezoelectric element used in the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
Figure 3 shows that A-AItI'1i7Ii in Figure 2 is 1 and 4th.
The figure is a [3-B [i3i] side view of FIG. 2, and FIG. 5(a). 6(b) and 6(a) and 6(b) are diagrams for explaining the present invention in detail, and FIG. 7 is a diagram showing another embodiment of the present invention. 10 Varnish chipping motor container, 11: Flange, 12
: Rotating shaft, 13.11!1: Bearing, 14, 15: Ring, 17: Rotation transmission means, 18 - Rotation prevention means, 1.9
,20.・21, 22: Electrode, 23: Moving member, 24:
Rotation drive means, 25: Insulator. 26: Spring, 27(a), (1+): Support material. 28: Insulator. Patent Applicant Hiki Electronics Co., Ltd. Representative Imu - Husband Figure 1 Figure 4 to End/b 2 Figure 2 Figure 7

Claims (1)

[Claims] a rotating shaft, a rotation preventing means which is made of a piezoelectric element and which blocks or enables rotation of the rotating shaft by controlling the voltage applied to the piezoelectric element, and a voltage which is made of a piezoelectric element and which is applied to the piezoelectric element. a rotation transmission means (1) that changes the state of being fixed to the rotation shaft and the state of releasing the fixation to the rotation shaft by control of the rotation transmission means; a rotation drive means for rotating the rotation transmission means; and the rotation prevention means 1. A stepping motor comprising: a rotational drive power source that applies electrical signals to each of a rotational transmission means and a rotational drive means to control rotation of the rotating shaft.