JP4572578B2 - Vibration actuator and manufacturing method thereof - Google Patents

Description

  The present invention relates to a vibration actuator that generates vibration in an elastic body, extracts vibration energy as an output, and obtains a driving force, and a method of manufacturing the vibration actuator.

Conventionally, in this type of vibration actuator, the accuracy (flatness, surface roughness, etc.) of the contact surface between the stator and the rotor greatly affects the motor performance. Therefore, after the surface treatment is performed on the elastic body, post-processing is necessary to obtain flatness.
In addition, in a stator of a traveling wave type ultrasonic motor provided with a stator having comb teeth, a technique for manufacturing the stator at a low cost is also known (for example, Patent Document 1).

FIG. 5 is a process diagram illustrating a method for manufacturing a stator in a conventional vibration actuator, and FIG. 6 is a cross-sectional view illustrating a side surface of the conventional stator.
In order to manufacture the stator 3, first, a masking layer is formed on the piezoelectric body bonding planned surface 31 c of the elastic body 31 cut into a predetermined shape [# 201], and the entire elastic body 31 is plated as a surface treatment. [# 202] Then, the masking layer is peeled off [# 203].
Then, the piezoelectric body 32 is heat-bonded to the piezoelectric body bonding planned surface 31c [# 204], and finally, post-processing for cutting the lapping margin Ra is performed [# 205].

  However, in the above-described conventional method, in order to ensure the flatness of the stator 3 required for the vibration actuator, the contact surface must be plated thicker in consideration of the amount to be shaved by post-processing, For example, in the case of PTFE-containing Nip plating, the thickness of the lap allowance Ra for post-processing is about 20 μm, which is wasteful, and the post-processing work time for cutting the lap allowance Ra is also long and troublesome. It was.

  Further, when the elastic body 31 and the piezoelectric body 32 are heat-bonded, the coefficient of thermal expansion of the two is different, so the stator 3 may be deformed, and uneven sliding and sliding at the rotor edge may occur. Since the width is reduced, problems such as the occurrence of uneven rotation, an increase in the starting rotational speed, and the generation of abnormal noise may occur.

JP-A-11-332262

  An object of the present invention is to provide a vibration actuator that can reduce the time and labor of post-processing for ensuring flatness and can obtain stable driving characteristics even with a stator that is deformed by heat bonding, and a method for manufacturing the vibration actuator. It is.

The present invention solves the above problems by the following means. In order to facilitate understanding, description will be made with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited to this.
According to the first aspect of the present invention, the elastic body (31) and the elastic body have different coefficients of thermal expansion, are joined to the elastic body (31), and the electromechanical transducer (32) excites the elastic body (31). And a rotor (4) in pressure contact with the elastic body (31) of the stator (3) and moving relative to the stator (3) by vibration. The contact portion in pressure contact with the rotor (4) of the elastic body (31) has a mirror-finished surface and a coating layer covering the mirror-finished surface (31a), and the elastic The body (31) is heated and joined to the electromechanical transducer (32), so that the contact portion is inclined in a middle convex or a middle concave, and the rotor (4) is connected to a moving object. First portion (41c) and the elastic body 31) connecting the first part (41c) and the second part (41a) with the second part (41a) having a contact surface in pressure contact with the contact part, A portion (41c) and a third portion (41b) having lower rigidity than the second portion (41a), and the third portion (41b) bends, whereby the elastic body (31) The vibration actuator is characterized in that the contact surface of the second portion (41a) is aligned with the inclined contact portion.

The invention according to claim 2 is the vibration actuator according to claim 1, wherein the mirror-finished surface (31a) has a center line average roughness of 1 μm or less.

According to a third aspect of the invention, the elastic body (31) and the elastic body have different thermal expansion coefficients, and are joined to the elastic body (31) to excite the elastic body (31). ), A first part (41c) connected to the object to be moved, and a second part having a contact surface in pressure contact with the contact part of the elastic body (31) ( 41a), the first part (41c) and the second part (41a) are connected, and the third part 41a) is lower in rigidity than the first part (41c) and the second part (41a). And a rotor (4) that is in pressure contact with the elastic body (31) of the stator (3) and moves relative to the stator (3) by vibration. In the manufacturing method, the rotor (4) of the elastic body (31). A mirror surface processing step (# 101) for mirror-processing the portion that is in pressure contact with, and a coating layer forming step for forming a coating layer that covers the mirror-finished surface after the mirror surface processing step (# 101), After the coating layer forming step (# 103), the step of heating and bonding the elastic body (31) and the electromechanical transducer (32), and bending the third portion (41b) The contact surface of the second portion (41a) of the rotor (4) is aligned with the contact portion of the elastic body (31) inclined in a middle convex shape or a concave shape by a joining step, and the stator (3) An assembling step of assembling the rotor (4).

Invention 請 Motomeko 4 is a method of manufacturing a vibration actuator according to claim 3, between the mirror-finished step (# 101) and the covering layer forming step (# 103), said electromechanical transducer (32 ), A masking layer forming step (# 102) for forming a masking layer on the planned bonding surface, and after the covering layer forming step (# 103), the masking layer is peeled off (# 104), It is a manufacturing method of a vibration actuator provided with the joining process (# 105) which joins the said electromechanical conversion element (32).

  According to the present invention, the contact surface of the elastic body is mirror-finished, and the coating layer that covers the contact surface is formed, so that the flatness of the contact surface can be ensured without performing post-processing, whereby post-processing This eliminates the need for work time and labor, and eliminates the need for lapping, thus reducing costs.

  In addition, since it includes an inclination corresponding portion that matches the contact surface of the rotor according to the inclination of the contact surface of the stator, even when the contact surface of the stator is inclined, the contact surface between the stator and the rotor is always parallel, Stable drive characteristics can be obtained.

  It is an object of the present invention to provide a vibration actuator that can reduce post-processing time and labor for ensuring flatness, and that can provide stable driving characteristics even with a stator that is deformed by heat bonding, and a method for manufacturing the same. The contact surface of the elastic body is mirror-finished to form a coating layer that covers the contact surface, and the rigidity of the fin portion is made lower than the rigidity of the hammer portion and the connection portion.

FIG. 1 is a sectional view showing an embodiment of a vibration actuator according to the present invention, FIG. 2 is a process diagram showing a method of manufacturing the vibration actuator according to this embodiment, and FIG. 3 is a stator and rotor according to this embodiment. FIG. 4 is a view showing the action of the fin portion.
As shown in FIG. 1, the stator (stator) 3 includes an elastic body 31, a piezoelectric body 32, and a support body 35.
The elastic body 31 is made of comb-like SUS, brass or the like that is joined to the piezoelectric body 32 and generates a progressive vibration wave on a contact surface 31a facing the rotor 4 described later by the excitation of the piezoelectric body 32.
The contact surface 31a of the elastic body 31 is mirror-finished and has a center line average roughness of 1 μm or less, and the contact surface 31a is covered with a PTFE-containing Nip plating (coating layer).
The piezoelectric body 32 is an electromechanical transducer such as PZT or ceramics that excites the elastic body 31 by a drive signal.
The support body 35 has a fixed ring 33 and a presser ring 34, and is a part that supports the elastic body 31 via the thin plate portion 31b.

The rotor (moving element) 4 is in pressure contact with the elastic body 31 of the stator 3 and moves relative to the stator 3 by vibration, and has a rotor base material 41 and a sliding material 42.
The rotor base material 41 includes a hammer part 41a having a sliding member 42 bonded to the lower part, a connection part 41c connected to a moving object (not shown), and a fin part (which connects the hammer part 41a and the connection part 41c). The rigidity of the fin part 41b is lower than the rigidity of the hammer part 41a and the connection part 41c.
The sliding member 42 is a member that is joined to the lower portion of the hammer portion 41a and is in pressure contact with the contact surface 31a of the elastic body 31 at the contact surface 42a.

Next, a method for manufacturing the vibration actuator according to the present embodiment will be described with reference to FIGS.
(1) The contact surface 31a of the elastic body 31 is mirror-finished [# 101].
(2) A masking layer is formed on the piezoelectric body bonding planned surface 31c of the elastic body 31 [# 102].
(3) The entire elastic body 31 is plated as a surface treatment to form a coating layer [# 103].
(4) The masking layer is peeled off to expose the piezoelectric material bonding planned surface 31c [# 104].
(5) The piezoelectric body 32 is bonded to the piezoelectric body bonding planned surface 31c using a high temperature curing type adhesive. At this time, since the elastic body 31 and the piezoelectric body 32 have different coefficients of thermal expansion, when the temperature is returned to room temperature, the stator 3 is inclined (center convex on the contact surface side) [# 105].
(6) The contact surface 42a of the rotor 4 is aligned with the contact surface 31a of the inclined stator 3, and the stator 3 and the rotor 4 are assembled [# 106].
Here, the operation of the fin portion 41b will be described. As shown in FIG. 4, the rigidity of the fin portion 41b is lower than the rigidity of the hammer portion 41a and the connecting portion 41c. The fin part 41b bends flexibly, and the contact surface 31a and the contact surface 42a come into surface contact. In the figure, the alternate long and short dash line is the rotation center of the vibration actuator.

  As described above, according to the present embodiment, the post-process is not required by mirror finishing, the cost for the lapping can be reduced, and the vibration actuator with less manufacturing variation can be stably manufactured by omitting the post-process. .

  Further, since the contact surface 42a of the rotor 4 is aligned with the contact surface 31a of the inclined stator 3, the contact surface 31a of the stator 3 and the contact surface 42a of the rotor 4 maintain parallelism, and drive characteristics do not vary.

  Furthermore, since the rigidity of the fin part 41b in the rotor 4 is lowered, the parallelism between the contact surfaces can be easily ensured.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
In the above-described embodiment, the inclination corresponding portion has been described with the example of the fin portion 41b having low rigidity. However, the rotor 4 may be manufactured so that the contact surface side of the rotor 4 is indented and may be used as the inclination corresponding portion. Also, contrary to the above-described embodiment, when the contact surface side of the stator 3 is indented, the rotor 4 is manufactured so that the contact surface side of the rotor 4 is indented in accordance with the shape. May be.

It is sectional drawing which shows the Example of the vibration actuator by this invention. It is process drawing which shows the manufacturing method of the vibration actuator by a present Example. It is sectional drawing which shows the side surface of the stator and rotor by a present Example. It is a figure which shows the effect | action of a fin part. It is process drawing which shows the manufacturing method of the stator in the conventional vibration actuator. It is sectional drawing which shows the side surface of the conventional stator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Stator 31 Elastic body 31a Contact surface 31b Thin plate part 32 Piezoelectric body 33 Fixed ring 34 Presser ring 35 Support body 4 Rotor 41 Rotor base material 41a Hammer part 41b Fin part 41c Connection part 42 Sliding material 42a Contact surface

Claims (4)

A stator having an elastic body and an electromechanical conversion element that is different in thermal expansion coefficient from the elastic body, is joined to the elastic body, and excites the elastic body;
A rotor in pressure contact with the elastic body of the stator and moving relative to the stator by vibration;
In a vibration actuator comprising:
The contact portion that is in pressure contact with the rotor of the elastic body has a mirror-finished surface and a coating layer that covers the mirror-finished surface,
The elastic body is heated and bonded to the electromechanical transducer, so that the contact portion is inclined in a middle convex or a middle concave,
The rotor includes a first portion connected to the moving target object, a second portion having a contact surface in pressure contact with the contact portion of the elastic body, the first portion, and the second portion. And the third portion having a lower rigidity than the first portion and the second portion, and the third portion is bent, whereby the inclined contact portion of the elastic body is formed. Aligning the contact surfaces of the second part;
Vibration actuator characterized by The vibration actuator according to claim 1,
The mirror-finished surface has a center line average roughness of 1 μm or less,
Vibration actuator characterized by A stator having an elastic body and an electromechanical conversion element that is different in thermal expansion coefficient from the elastic body, is joined to the elastic body, and excites the elastic body;
A first portion connected to a moving object, a second portion having a contact surface in pressure contact with the contact portion of the elastic body, and the first portion and the second portion; A rotor that has a first portion and a third portion that is less rigid than the second portion, is in pressure contact with the elastic body of the stator, and moves relative to the stator by vibration;
In a manufacturing method of a vibration actuator comprising:
Mirror surface processing step of mirror processing the portion of the elastic body that is in pressure contact with the rotor;
A coating layer forming step of forming a coating layer that covers the mirror-finished surface after the mirror finishing step;
After the coating layer forming step, a bonding step of heat bonding the elastic body and the electromechanical conversion element;
By bending the third portion, the contact surface of the second portion of the rotor is aligned with the contact portion of the elastic body inclined in a middle convex or a concave shape by the joining step, and the stator and the An assembly process for assembling the rotor;
A method of manufacturing a vibration actuator comprising: In the manufacturing method of the vibration actuator according to claim 3,
A masking layer forming step of forming a masking layer on the planned joining surface of the electromechanical transducer between the mirror surface processing step and the coating layer forming step,
The manufacturing method of a vibration actuator provided with the joining process which peels the said masking layer and joins the said electromechanical conversion element to the said joining plan surface after the said coating layer formation process.

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