JPH09219981A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a motor which can always ensure a pressurized contact condition between a stator and a motor with a simple construction, maintain rotation transmitting efficiency, and equalize rotation driving. SOLUTION: This motor is provided with a housing 9, on which an inner circumferential part of a stator 4 is fixed and supported. On the other hand, a flange part 15 is fitted at the external side of a rotor 7. Pressurizing force from a disc spring 14 works upon the flange part 15 through a plate 17 which includes a circular body 16, and the rotor 7 and the stator 4 are brought into pressurized contact by a pressurizing action. Namely, a pressurizing point upon the flange part 15 of the rotor 7 is provided on the external side, to the fixing and supporting position of the stator 4, with a contact part between the rotor 7 and the stator 4 between. Therefore, the deflecting direction of the rotor 7 and the stator 4 which results from various kinds of factors such as a pressurizing action by the disc spring 14 is made the same as each other, thus always ensuring a contact condition between the rotor 7 and the stator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor using a traveling wave excited by mechanical resonance in a vibrator composed of an electrostrictive element, a piezoelectric element, a magnetostrictive element, etc. The present invention relates to an ultrasonic motor capable of always ensuring a contact portion between a stator and a rotor to maintain rotation transmission efficiency and uniform rotation driving.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 4 and 5, an ultrasonic motor has a stator 4 formed by attaching a disk-shaped piezoelectric vibrator 1 to the back surface of an elastic body 3 formed around a disk 2. A shaft hole 6 is provided in the center of the disk 5, and a circular rotor 7 formed in the periphery is pressed against the surface of the elastic body 3 of the stator 4. Further, a thick portion 2 ′ having a shaft insertion hole 8 formed at the center of the disc 2 of the stator 4 is fixed to a central thick portion 9 ′ of the bottom plate of the housing 9, and the bearing 10 is attached to the thick portion 9 ′.
A shaft 11 rotatably attached via a shaft is loosely fitted in the shaft insertion hole 8 of the disk 2 of the stator 4 and is press-fitted and fixed in the shaft hole 6 of the disk 5 of the rotor 7. Further, the disk 5 is always provided on the stator 4 by means of a disc spring 14 or the like, which is received by a plate 13 supported by a nut 12 at the end of the shaft 11.
Since it is biased to the side, the pressing by the disc spring 14 and the like is performed inside the contact surface between the rotor 7 and the elastic body 3 of the stator 4.

[0003]

However, in the pressurization with the above-mentioned structure, the supporting portion of the stator 4 and the point of action of pressurizing the rotor 7 are on the same side with respect to the contact surface, As shown in FIG. 5, the disk 5 and the disk 2 are flexed by the pressing force of the spring, flexed by the vibration of the stator, or flexed due to metal fatigue such as change with time. Bends in the opposite direction.

As a result, the contact surface between the stator 4 and the rotor 7, which are in pressure contact with each other, opens to the outside, resulting in poor contact, which deteriorates the rotation transmission efficiency and causes unevenness in rotation drive, resulting in non-uniformity. .

The present invention has been made in order to solve the above problems, and an object thereof is to always ensure a pressure contact state between a stator and a rotor with a simple structure,
It is intended to maintain the rotation transmission efficiency and make the rotation drive uniform.

[0006]

In order to achieve the above object, in the first aspect of the present invention, there is provided a super structure including a housing, a stator to which a vibrator is attached, and a rotor which rotates by being in pressure contact with the stator. The sonic motor has a pressurizing means for generating pressurizing force for the pressurizing contact, and a pressurizing force distributing means for distributing and applying the pressurizing force of the pressurizing means, and the stator is provided in the housing. It is fixedly supported by the peripheral portion, and the pressing action point by the pressing force distribution means is provided outside the supporting position of the stator with the contact portion between the stator and the rotor being sandwiched.

According to the second aspect of the invention, in an ultrasonic motor comprising a housing, a stator provided with a vibrator, and a rotor which rotates by being in pressure contact with the stator, the ultrasonic motor is used for the pressure contact. A pressurizing means for generating a pressurizing force and a pressurizing assisting means for imparting the pressurizing force of the pressurizing means evenly, and the stator is fixedly supported by the inner peripheral portion of the housing. The pressurizing action point is provided on the outer side of the supporting position of the stator with the contact portion between the stator and the rotor being sandwiched therebetween.

[0008]

With the above means, in both the first and second inventions,
The stator is fixedly supported on the housing at the inner peripheral portion, and
The point of pressurizing action on the rotor is provided outside the support position of the stator with the contact portion between the stator and the rotor being sandwiched. Therefore, the rotor is deflected toward the stator side and the stator is deflected in the same direction as the rotor due to fatigue such as pressurizing action on the rotor, vibration due to the stator, and temporal change. Therefore, the contact portion between the stator and the rotor, which are in pressure contact with each other, does not open and the contact state is maintained, whereby the rotation transmission efficiency is maintained and the rotor is uniformly driven without uneven rotation.

In particular, in the first aspect of the invention, since the pressing force of the pressurizing means is distributed by the pressing force distribution means to bring the rotor and the stator into pressure contact, the pressing force is distributed to an appropriate position to operate. Can be made.

Further, in the second aspect of the present invention, since the pressing force of the pressurizing means is uniformly applied by the pressing assisting means to bring the rotor and the stator into pressure contact, the pressing force is appropriately balanced. Can act on position.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention.

A disk-shaped piezoelectric vibrator 1 is provided with a stator 4 attached to the back surface of an elastic body 3 formed around the disk 2,
A circular hole 7 is formed in the center of the circular plate 5 and a circular rotor 7 formed in the periphery of the circular plate 5 is made to correspond to the surface of the elastic body 3 of the stator, and a flange portion 15 is provided outside the rotor 7.
Are integrally formed.

A shaft insertion hole 8 is formed in the center of the disk 2 of the stator 4.
The thick portion 2'having a hole is fixed to the central thick portion 9'of the bottom plate of the housing 9, and the shaft 11 rotatably attached to the thick portion 9'via a bearing 10 is a circle of the stator 4. It is loosely fitted in the shaft insertion hole 8 of the plate 2 and the shaft hole 6 of the disc 5 of the rotor 7. A plate 17 having a circular body 16 in contact with the surface of the flange portion 15 of the rotor 7 opposite to the elastic body 3 side is provided with a shaft 17 formed in a shaft hole 18 formed at the center thereof.
Is fixed by press-fitting, and the plate 17 is constantly urged toward the stator 4 side by the disc spring 14 or the like received by the plate 13 supported by the nut 12 at the end of the shaft 11.

The disc spring 14 constitutes a spring member as a pressing means of the present invention. Further, the plate 17 having the circular body 16 constitutes a plate member and a pressurizing assisting means as a pressing force distributing means of the present invention.

With the above structure, when the rotor 7 and the stator 4 are bent by the pressure applied to the outer flange portion 15 of the rotor 7, the rotor 7 is bent toward the stator 4 and the stator 4 is bent in the same direction as shown in FIG. Therefore, the surface contact between the two is maintained.

Further, in the above structure, the pressing force generated from the disc spring 14 is applied to the outer flange portion 15 of the rotor 7 via the plate 17 having the circular body 16.
Therefore, the plate 17 having the circular body 16 can apply a uniform and balanced pressure force to the rotor 7, and the rotor 7 can be smoothly driven without an unbalanced load. Moreover, plate 1
Due to the presence of 7, the disc spring 14 having a small diameter can be used as shown in the drawing, and the decrease of the pressing force of the disc spring 14 and the deterioration of the spring property can be prevented or suppressed.

FIG. 3 shows another embodiment of the present invention, in which the stator 4 and the rotor 7 are formed in an annular shape, and are formed on the inner circumference of the annular elastic body 21 so as to project. The flange portion 22 is engaged with and supported by a step portion 24 formed at the tip of a cylindrical housing 23.

In the figure, parts designated by the same reference numerals indicate the same constituent parts.

[0019]

As described in detail above, according to the first and second aspects of the present invention, a good contact state is maintained even if the rotor and the stator that comes into contact with the rotor bend due to the pressure applied to the rotor. As a result, the rotation transmission efficiency is maintained without being lowered, and accordingly, the rotation drive is not uneven, and uniform and good rotation can be obtained.

According to the first aspect of the invention, in addition to the above effects, the pressing force of the pressurizing means is distributed by the pressing force distributing means to bring the rotor and the stator into pressure contact.
The pressing force can be distributed to appropriate positions to act.

According to the second invention, in addition to the above effects,
Since the pressure applied by the pressure applying means is applied by the pressure assisting means without bias to bring the rotor and the stator into pressure contact with each other, it is possible to apply the pressure applied to a proper balanced position.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the bending is generated.

FIG. 3 is a sectional view showing the configuration of another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a conventional example.

FIG. 5 is a cross-sectional view showing a state in which the bending is generated.

[Explanation of symbols]

1 ... Disc-shaped piezoelectric vibrator as a vibrator, 4 ... Stator,
7 ... Rotor, 9 ... Housing, 14 ... Belleville spring which constitutes a spring member as a pressing means, 15 ... Flange part 16,
17 ... A circular body and a plate constituting a plate member and a pressurizing assisting means as a pressing force distributing means.

Claims (4)

[Claims] 1. An ultrasonic motor comprising a housing, a stator to which a vibrator is attached, and a rotor that rotates by being in pressure contact with the stator, wherein a pressing force for generating the pressing contact is generated. A pressurizing unit and a pressurizing force distributing unit that distributes and applies the pressurizing force of the pressurizing unit, and the stator is fixedly supported by the inner peripheral portion of the housing,
The ultrasonic motor, wherein the pressing action point by the pressing force distribution means is provided outside the support position of the stator with the contact portion between the stator and the rotor being sandwiched therebetween. 2. The pressurizing means is a spring member, and the pressurizing and distributing means is a disk-shaped plate member, and the pressurizing force of the spring member is applied via the plate member to the pressurizing action point of the rotor. 5. The method according to claim 1, wherein
The described ultrasonic motor. 3. An ultrasonic motor comprising a housing, a stator to which a vibrator is attached, and a rotor which rotates by being in pressure contact with the stator, wherein a pressing force for generating the pressing contact is generated. A pressurizing means and a pressurizing assisting means for imparting the pressurizing force of the pressurizing means without imbalance, and the stator is fixedly supported by the inner peripheral portion of the housing,
An ultrasonic motor, wherein the pressing action point by the pressing assist means is provided outside the supporting position of the stator with the contact portion between the stator and the rotor being sandwiched therebetween. 4. The rotor according to claim 1, wherein the rotor has a flange portion extending to the outside of the contact portion, and the pressurizing point presses the flange portion. The described ultrasonic motor.