JPS63287375A - Oscillatory wave motor - Google Patents

Abstract

PURPOSE:To enlarge a working range, by changing a pressure contacting force between an oscillating unit and a driven object, and by setting a pressure varying device for changing a driving force. CONSTITUTION:Of an electrostriction element 1, an oscillating unit 2, an oscillation absorber 4, a base 5, a stationary shaft 6, and the like, an oscillatory wave motor is composed. An electrostriction element 12 is retained between the base 5 and the oscillation absorber 4, and is worked as a pressure changing element. Then, the electrostriction element 12 is formed so that a displacement in the shaft core of the stationary shaft 6 may generate, and when a driving force is increased, then voltage is applied to so that the thickness of the electrostriction element 12 may decrease, and the pressure of a frictional contact section is reduced, and the driving force is reduced. On the other hand, when the driving force is reduced, then the thickness of the electrostriction element 12 is increased, and the ununiformity of the driving force can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vibration wave motor comprising a vibrating body that generates vibration waves and an object that is in frictional contact with the vibrating body and is driven by the vibration waves. In particular, the present invention relates to a vibration wave motor equipped with a pressure variable device that changes the frictional contact force.

[Prior Art] A conventional vibration wave motor has a configuration as shown in FIG. 10, for example.

In FIG. 10, 1 is an electrostrictive element, for example, PZT.
(lead zirconate titanate), 2 is a vibrating body made of an elastic material, to which the electrostrictive element 1 is adhered. The vibrating body 2 and the electrostrictive element 1 are held on a base 5 via a vibration absorber 4. 3 is a driven substance, bearing 11
It is rotatably supported by a fixed shaft 6 via a bushing 10. The lower end of the fixed shaft 6 is attached to the base 5, and the upper end is screwed. Further, a spring 9 is fitted to the upper end of a bush 10 on the fixed shaft 6, and a nut is screwed in through a washer 8. Object 3 driven by this
is pressed against the vibrating body 2.

In principle, a vibration wave motor that is driven by vibration waves:
A vibrating body 2 and an object 3 driven by frictional contact with the vibrating body 2
Since it is necessary to bring them into pressure contact, mechanical means such as a spring 9 and a nut are used to achieve a moderately constant pressure contact.

[Problems to be Solved by the Invention] As mentioned above, in the conventional vibration wave motor, the vibrating body 2 and the driven object 3 are brought into pressure contact with each other with a moderate constant pressing force. There is unevenness in the driving force caused by changes in the frictional contact area due to surface conditions and eccentricity of the contact part of the object 3 being driven, and because it was not possible to change the unevenness of the driving force, the range of use is limited. There was a problem. The present invention attempts to solve these problems. That is, an object of the present invention is to provide a vibration wave motor that can be used in a wide range of applications by changing the unevenness of the driving force.

[Means for Solving the Problems] A pressurizing force variable device is provided which changes the driving force by changing the pressurizing contact force between the vibrating body of the vibration wave motor and the driven object.

[Operation] Since the pressurizing force variable device is provided, it is possible to change the pressurizing contact force between the vibrating body and the driven object to change the driving force as desired.

[Example code] FIG. 1 shows a first embodiment of the invention.

In FIG. 1, 1 is an electrostrictive element, 2 is a vibrating body, 3 is a driven object, 4 is a vibration absorber, 5 is a base, 6 is a fixed shaft,
7 is a nut, 8 is a washer, 9 is a spring, 10 is a bush, and 11 is a bearing, which is the same as the conventional one shown in FIG. 10. 12 is an electrostrictive element, and a base 5
The fixed shaft 6 is held between the fixed shaft 6 and the vibration absorber 4, and is arranged so that the fixed shaft 6 is displaced in the axial direction by voltage. That is, the electrostrictive element 12 constitutes the main part of the pressurizing force variable device, and functions as a pressurizing force varying element, as will be described later.

As mentioned above, in the vibration wave motor driven by vibration waves, it is necessary to pressurize the vibrating body 2 and the object 3 that is driven by frictional contact with the vibrating body 2, and this pressurizing force and driving force are as follows. It has the characteristics shown in Figure 4. Therefore, when the driving force becomes uneven due to changes in the friction contact area due to the surface condition of the friction contact part or eccentricity, etc., the O-
The unevenness of the driving force can be reduced by using the characteristics between the A points. In other words, when the driving force becomes large, the pressurizing force is decreased to make the driving force smaller, and conversely, when the driving force becomes small, the pressurizing force is increased to increase the driving force. , it is possible to reduce the unevenness of the driving force.

The fifth is a block diagram showing an example of means for detecting unevenness in driving force and controlling the unevenness.

To explain further, in the embodiment shown in FIG. 1, the electrostrictive element 12 is used as the pressurizing force changing element, and is arranged so that the fixed shaft 6 is deformed in the axial direction. Sometimes, a voltage is applied to reduce the thickness of the electrostrictive element 12, reducing the pressing force on the frictional contact portion and reducing the driving force. Conversely, when the driving force becomes small, a voltage is applied so as to increase the thickness of the electrostrictive element 12, increasing the pressing force on the frictional contact portion and increasing the driving force. In this way, the unevenness of the driving force can be reduced. Note that if the opposite setting is made, the unevenness of the driving force can be increased. Furthermore, if the spring 9 is omitted to eliminate the pressing force at the friction contact part, and the electrostrictive element 12 is applied with a laminated electrostrictive element that can have a stroke,
Since the frictional force between the vibrating body 2 and the driven object 3 can also be changed freely, an actuator that can be used in a wider range can be constructed.

FIG. 2 shows a second embodiment of the invention, and FIG. 3 similarly shows a third embodiment. In these embodiments, an electrostrictive element 13 that changes the pressing force of the frictional contact portion is arranged on the spring 9 side, and the electrostrictive element 13 has the same effect as the electrostrictive element 12 explained in FIG. do.

FIG. 6 shows a fourth embodiment of the invention.

In this embodiment, a magnetic body 14 and an electromagnetic coil 15 are used as the force varying element of the force variable device, and the attractive force of the magnetic body 14 and the electromagnetic coil 15 is used to change the force applied to the frictional contact portion. be.

That is, the magnetic body 14 is fixed to the object 3 to be driven,
The electromagnetic coil 15 is fixed to the base 5, and the magnetic body 14
and the electromagnetic coil 15 face each other with a slight distance from each other. In such a configuration, for example, when the driving force of the vibration wave motor becomes small, the current of the electromagnetic coil 15 is increased to increase the adsorption force of the magnetic body 14, and the pressing force of the friction contact portion is increased to increase the driving force. Try to make it larger.

On the other hand, when the driving force becomes large, the opposite operation is performed to reduce the driving force.

FIG. 7 shows a fifth embodiment of the present invention.

This embodiment includes a permanent magnet 16 fixed to the object 3 to be driven and an electromagnetic coil 17 fixed to the housing 18.
This changes the pressure applied to the friction contact area. That is, the permanent magnets 16 and 1 and the magnetic coil 17 face each other with a slight distance from each other, and the direction of current is determined in the electromagnetic coil 17 so as to repel the permanent magnet 16. In such a configuration, for example, when the driving force becomes small, the current of the electromagnetic coil 17 is increased to increase the repulsive force with the permanent magnet 16, and the pressing force of the friction contact portion is increased to increase the driving force. do it like this. On the other hand, when the driving force becomes large, the opposite operation is performed to reduce the driving force.

FIG. 8 shows a sixth embodiment of the invention.

In this embodiment, a permanent magnet 19 fixed to an object 3 to be driven, and a permanent magnet 20 and an electromagnetic coil 21 fixed to a base 5 face each other with a slight distance from each other. The direction of the permanent magnet 20 is determined so as to attract it, and the vibrating body 2 is brought into pressurized contact with the object 3 driven by the attraction force. In such a configuration, by increasing/decreasing the current of the electromagnetic coil 21 and changing the direction of the current, it is possible to change the pressing force of the frictional contact part, so that the unevenness of the driving force can be reduced as described above. .

FIG. 9 shows a seventh embodiment of the invention.

In this embodiment, a permanent magnet 16 fixed to an object 3 to be driven, and a permanent magnet 22 and an electromagnet 23 fixed to a housing 18 face each other with a slight distance apart. Directed to repel,
The object 3 driven by the repulsive force and the vibrating body 2 are brought into pressure contact. In such a configuration, the electromagnetic coil 2
By increasing/decreasing the current and changing the direction of the current in step 3, it is possible to change the pressing force on the frictional contact portion, so it is possible to reduce the unevenness of the driving force as described above.

In the above explanation, we mainly talked about reducing the unevenness of the driving force, but it is also possible to increase the unevenness of the driving force, and although we talked about rotary type vibration wave motors, linear type It can also be applied to vibration wave motors.

[Effects of the Invention] The present invention includes a pressurizing force variable device that changes the driving force by changing the pressurizing contact force between the vibrating body of the vibration wave motor and the driven object, so that it is possible to change the unevenness of the driving force. Therefore, the range of use can be expanded from those that require small unevenness of driving force to those that require large unevenness of driving force, and the setting of the driving force can be expanded. It also becomes easier.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing a first embodiment of the present invention;
Fig. 2 is a partially cutaway side view of the main part similarly showing the second embodiment, Fig. 3 is a partially cutaway side view of the main part similarly showing the third embodiment, and Fig. 4 is a friction contact of the vibration wave motor. FIG. 5 is a block diagram showing an example of means for controlling unevenness of the driving force, and FIG. 6 is a partial diagram showing the fourth embodiment of the present invention. FIG. 7 is a partially cutaway side view of the fifth embodiment, and FIG. 8 is a partially cutaway side view of the fifth embodiment.
FIG. 9 is a partially cutaway side view showing the seventh embodiment; FIG. 10 is a partially cutaway side view showing an example of the conventional technique. 1... Electrostrictive element 2... Vibrating body 3... Driven object 4... Vibration absorber 5... Base
6...Fixed shaft 7...Nut
8...Washer 9...Spring 10.
...Bushing 11...Bearing 12.13.
... Electrostrictive element 14 ... Magnetic body 15 ... Electromagnetic coil 16 ... Permanent magnet 17 ... Electromagnetic coil 18 ... Housing 19. 20 ... Permanent magnet 21 ... as magnetic coil 22 ...Permanent magnet 2
3... Electromagnetic coil Fig. 1 Fig. 27 Fig. 3 Dormitory Fig. 4 Fig. 5 Fig. Book Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 6 4 ]

Claims (1)

[Claims] (1) In a vibration wave motor consisting of a vibrating body that generates vibration waves and an object that is in frictional contact with the vibrating body and driven by the vibration waves, pressurized contact between the vibrating body and the driven object A vibration wave motor characterized by being equipped with a pressurizing force variable device that changes driving force by changing force.