JPH03253270A - Oscillatory wave motor - Google Patents

Abstract

PURPOSE:To prevent an oscillation body from overheating to stabilize a characteristic of a motor and, at the same time, to prevent coming-off of a piezo-electric body by forming a thermal conduction path for radiating heat generating in the oscillation body to a radiation member through a thermal conduction member. CONSTITUTION:Temperature rising in a motor caused by heating of a stator 5 is conducted and radiated to a case 1 from a cover 2 through a thermal conduction member 16 brought into contact with the lower face 4-a of a piezo-electric body 4 and the inside 2-b of the cover 2 by holding between them instead of a path to be conducted and radiated through the cover 2 to case 1 from the stator 5. According to the constitution, overheating of the stator 5 is prevented, variation in resonance frequency of an oscillation body caused by overheating is eliminated to stabilize the characteristic of a motor and, at the same time, deterioration or coming-off of adhesives can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a progressive vibration wave type vibration wave motor.

[Prior Art] A proposal regarding the structure of a vibration wave motor that utilizes bending vibration of a piezoelectric body is disclosed in Japanese Patent Laid-Open No. 63-73887.

The above proposal is 1) Small and compact vibration wave motor 2> Vibration wave motor with excellent heat dissipation 3) Highly efficient vibration wave motor 4) Vibration wave motor with easy pressure adjustment It provides:

Since the driving principle of the vibration wave motor is well known, it will not be explained in detail, but will be briefly explained below.

In a vibration wave motor, a piezoelectric element is bonded with adhesive to one side of an elastic body made of metal, for example, formed in an annular shape, and two groups of piezoelectric elements for driving formed on the piezoelectric element have different phases. By applying an alternating voltage, two standing waves are excited on the elastic body, and these standing waves are combined to form a progressive vibration wave, which is a bending vibration.

On the other hand, on the other side of the elastic body, an annular member, for example, is pressurized via a pressure means such as a spring, and the member is moved by friction drive caused by progressive vibration waves formed in the elastic body. or move the elastic body.

A conventional example will be explained with reference to FIG.

2 is a cover of the motor, and 1 is a case. A piezoelectric body 4 is fixed to the annular elastic body 3, and these constitute a stator (vibrating body) 5.

Note that the stator 5 generates heat due to thermal energy generated by electrostriction due to energization of the piezoelectric body 4, and the structure is such that the increase in motor temperature due to the heat generation of the stator 5 is conducted and dissipated from the stator 5 to the cover 2 and the case 1. It has become.

Reference numeral 8 denotes a rotor constructed by fixing a slider 7 to a ring 6. This rotor 8 is pressed against the stator 5 by the pressing force of a spring 10 with a rubber body 9 in between, and rotates integrally with a shaft 11. . The pressing force can be adjusted very easily since the thickness of the shim 12 is appropriately selected and adjusted and then held by the snap ring 13. The shaft 11 is rotatably supported by bearings 14 and 15 attached to the case 1 and the cover 2, respectively.

[Lesson 1 that the invention attempts to solve! ! ! ] By the way, in the above conventional example, the transmission path of the thermal energy generated in the stator 5 during driving is heat radiation from the surface of the stator 5,
There are three paths: one from the drive surface to the rotor, and the other from the stator thin wall portion 3-a to the cover 2 and case 1 through the stator mounting portion 3-b. The thermal energy conducted to the rotor 8 is very small, and most of it is transferred from the third path from the stator thin wall section 3-a to the cover 2 via the attachment section 3-b.
, will be conducted and dissipated to case 1.

In this case, the amount of heat conducted per unit time is proportional to the cross-sectional area perpendicular to the conduction direction, so in the conventional example, the cross-sectional area of the thin-walled portion 3-a for providing flexibility is extremely small, and the amount of heat conducted per unit time is The amount of heat that can be conducted and dissipated to the outside of the motor is extremely small, which may lead to overheating of the stator 5, resulting in deterioration of the motor characteristics due to the temperature dependence of the stator resonance frequency, and the adhesive that fixes the piezoelectric body 4 and the elastic body 3. In some cases, strength reduction or peeling occurred.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration wave motor that solves these conventional problems, stabilizes motor characteristics by preventing overheating of a vibrating body, and prevents peeling of a piezoelectric body.

[Means for Solving the Problems] The gist of the present invention is to apply an alternating current voltage to an electro-mechanical energy conversion element bonded to an elastic body, thereby causing the elastic body to move forward. It has a vibrating body that forms elastic vibration waves, and a member that is pressed against the vibrating body through a pressure means, and the member and the vibrating body are moved relative to each other by the progressive vibration waves formed in the elastic body. In a vibration wave motor to be moved, at least one heat conductive member is disposed in contact with the vibrating body or with a gap therebetween, and the heat generated in the vibrating body is radiated to the heat radiating member via the heat conductive member. A vibration wave motor is characterized in that a heat conduction path is formed.

[Function] The vibration wave motor configured as described above directly guides the heat generated in the vibrating body to the heat radiating member via the heat conducting member.

[Embodiments] The present invention will be described in detail below based on embodiments shown in the drawings.

In the description of the embodiment, members having the same structure as those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

Embodiment 1 FIG. 1 is a sectional view showing Embodiment 1 of a vibration wave motor according to the present invention.

The structure of the vibration wave motor of this embodiment has substantially the same basic structure as that of the conventional example shown in FIG. be.

In other words, the increase in motor temperature due to heat generation in the stator 5 is
Apart from the path for conducting and dissipating from the stator 5 to the cover 2 and the case 1, the piezoelectric body 4 is sandwiched between the lower surface 4-a of the piezoelectric body 4 and the inner surface 2-b of the cover 2 and comes into contact with each of the aforementioned surfaces. A heat conductive member 16 is arranged. The heat of the stator 5 is conducted and dissipated from the cover 2 to the case 1 through the heat conduction member 16.

Contact surface 1B- of lower surface 4-a of piezoelectric body 4 and heat conductive member 16
a, the inner surface 2-b of the cover 2, and the contact surface 16-b of the heat conductive member 16 each have a large contact area, so that the thermal energy generated in the stator 5 is quickly conducted and dissipated, preventing overheating of the stator 5. To prevent.

For example, if Sumitomo 3M's Fluorinert (trade name) Liquid Heat Sink (registered trademark), in which a heat-absorbing liquid is packaged in a plastic film, is used as the heat-conducting member 16, it will deform along the shape of the contact area and increase the contact area. However, it further improves heat conduction, hardly restricts vibration of the stator, and does not cause a decrease in efficiency.

The heat conduction member 16 has a wavelength (
λ), a plurality of them are arranged at intervals of one wavelength (λ). This is because the height of the amplitude of the traveling wave is the same at the placement position of each heat conductive member 16, so that the vibration of the vibrating body is not affected, and good contact between the multi-thermal conductive member 16 and the vibrating body is achieved. Due to the fact that sex is obtained.

In addition, it is most effective from the point of view of thermal conductivity to bring the heat conductive member 16 into direct contact with the vibrating body as in this embodiment, but in consideration of the influence on the vibration of the vibrating body, heat conduction Member 16
It is also effective to place them facing each other with a slight distance between them.

Furthermore, by increasing the heat dissipation area by providing heat dissipation fins or the like on the case 1 and the cover 2, the heat dissipation effect is further improved.

Embodiment 2 FIG. 2 is a sectional view showing Embodiment 2 of the vibration wave motor according to the present invention.

In this embodiment, a fan 17 is fixed to one end 11-a of the shaft 11 of the vibration wave motor in the first embodiment described above.

That is, the heat of the stator 5 is radiated from the stator 5 through the path of the cover 2, and from the stator 5 to the heat conductive member 1.
6 to the cover 2 and case 1, and is quickly dissipated by the wind sent by the fan 17 that rotates during operation.

[Effects of the Invention] As explained above, according to the present invention, the heat of the stator is dissipated by sandwiching a heat conductive member between a vibrating body such as the stator and a heat dissipating member such as a cover to provide a heat conduction path. It conducts and dissipates quickly to prevent overheating of the stator, eliminate changes in the resonant frequency of the vibrating body due to overheating, stabilize the motor characteristics, and fix the vibrating body to an electro-mechanical energy conversion element such as a piezoelectric body. This eliminates adhesive deterioration and peeling, and provides an extremely stable and highly reliable vibration wave motor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of a vibration wave motor according to the present invention, FIG. 2 is a sectional view of a second embodiment, and FIG. 3 is a sectional view of a conventional vibration wave motor. 1...Motor case 2...Cover 3...
Elastic body 4... Piezoelectric body 5... Stator (vibrating body) 6... Ring 7... Slider
8... Rotor 9... Rubber ring 10.
...Rice spring 11...Shaft 12...Spacer 13...Snap ring 14.15-...Bearing 16...Heat conduction member 17...Fan and 4 other people

Claims (1)

[Scope of Claims] 1. A vibrating body that forms progressive vibration waves in the elastic body by applying an alternating current voltage to an electro-mechanical energy conversion element bonded to the elastic body, and a means for applying pressure to the vibrating body. A vibration wave motor that has a member that is pressed into contact with the vibrating body and moves the member and the vibrating body relative to each other by a progressive vibration wave formed in the elastic body, the vibrating body having at least one heat conductive member. A vibration wave motor characterized in that the vibration wave motor is arranged so as to be in contact with each other or with a gap therebetween, and to form a heat conduction path for radiating heat generated in the vibrating body to a heat radiating member via the heat conduction member. 2. The vibration wave motor according to claim 1, wherein the heat radiation member is a cover or a case of the vibration wave motor. 3. The vibration wave motor according to claim 1, wherein a plurality of heat conductive members are arranged at intervals of one wavelength of the traveling wave formed in the elastic body. 4. The vibration wave motor according to claim 1, 2 or 3, wherein the heat radiation member is provided with a concave portion or a convex portion for increasing the heat radiation area. 5. The vibration wave motor according to claim 1, 2, 3 or 4, further comprising a cooling means using air blowing.