JP5627448B2 - Vibration type driving device - Google Patents

Description

  The present invention relates to a vibration type driving device called an ultrasonic actuator or the like that has a vibrating body and a moving body and drives the moving body, and particularly relates to the shape of the moving body or the vibrating body.

Conventionally, a vibration type driving device (ultrasonic actuator) that drives a moving body by vibration generated by the vibrating body is known.
The vibrating body in such a vibration type driving apparatus is generally composed of an elastic body and a piezoelectric element as an electro-mechanical energy conversion element disposed on the elastic body.
For example, a piezoelectric element having two driving phases is disposed at a position spatially having a phase difference of 90 ° with respect to the elastic body, and two alternating currents having a phase difference of 90 ° with respect to the two driving phases. Two bending vibrations are generated on the elastic body by applying a signal.
The moving body is moved relative to the vibrating body by the drive signal obtained by combining the two bending vibrations.
A friction member for obtaining an appropriate frictional force is bonded, applied, or formed on the contact surface of at least one of the vibrating body and the moving body.

The friction member wears as the moving body is slid with respect to the vibrating body. However, the life of the vibration type driving device can be increased by delaying the wear.
It has been confirmed that the contact surface pressure between the moving body and the vibrating body is one of the factors that determine the wear rate. By reducing these contact surface pressures, the life of the vibration-type drive unit can be increased. It becomes.
As a method for reducing the contact surface pressure, it is conceivable to increase the area of the contact portion.
Further, it is necessary to give elasticity to the contact portion so as not to generate abnormal noise during driving.
In order to solve these two factors, for example, as in Patent Document 1 shown in FIG. 18, an ultrasonic motor having a structure in which a contact portion is formed of a beam-like member and supports both ends of the contact portion has been proposed. .
As shown in FIG. 18, this ultrasonic motor is composed of a vibrating body in which a piezoelectric body is coupled to an elastic substrate, and a carbon fiber reinforced composite reinforced with carbon fibers, and a beam structure under both-end support conditions. It consists of a moving body.
The moving body includes a moving body beam portion, a moving body first protrusion extending from both ends of the beam portion, and a moving body second protrusion extending from the beam portion on the contact surface side with the vibrating body. It is configured.
Since the material of the moving body is resin and the moving body has a beam portion having a two-step projection structure, an effect for absorbing the undulation of the contact surface between the moving body and the vibrating body occurs. Accordingly, the uniform contact between the moving body and the vibrating body can be stably maintained.

Japanese Patent No. 03049931

FIG. 19 shows the result of simulating the contact surface pressure with a structure like the vibration type driving device described in Patent Document 1.
FIG. 19 shows a distribution of contact surface pressure at the contact portion between the driven portion and the vibrating body when a force is applied to the driven portion and brought into pressure contact with the vibrating body, and the surface pressure is higher toward the top of the graph. It is shown that.
As described above, in the structure of the conventional example, the contact surface pressure is concentrated on both ends of the second protrusion due to the deflection of the beam portion, which causes a problem in improving the durability of the vibration type driving device.
In order to improve the durability of such a vibration type driving device, it is desirable not only to increase the contact area between the moving body and the vibrating body but also to disperse the entire pressure on the contact surface.

  The present invention solves the above-mentioned problems and expands the contact area between the moving body and the vibrating body in order to reduce the contact surface pressure, while improving the durability by dispersing the contact surface pressure entirely on the contact surface. It is an object of the present invention to provide a vibration type driving device that can be realized.

The vibration-type driving device of the present invention includes an oscillating unit that is attached with an electro-mechanical energy conversion element and vibrates when a driving voltage is applied to the electro-mechanical energy conversion element.
A vibration-type driving device having a driven portion that is in frictional contact with the vibration portion and the contact portion and moves relative to the vibration portion by vibration of the vibration portion;
The contact portion is supported by two support portions made of a material having a spring property, protruding from either the driven portion or the vibrating portion to the other side thereof,
Between the two support parts, a region is formed in which the interval is narrower than the width of the contact part supported by these support parts.

  According to the present invention, in order to reduce the contact surface pressure, the contact area between the moving body and the vibrating body is expanded, while the durability can be improved by dispersing the contact surface pressure over the entire contact surface. The vibration type driving device can be realized.

It is a figure which shows the structural example of the vibration type drive device in Example 1 of this invention. It is a figure which shows the structural example of the to-be-driven part in the vibration type drive device of Example 1 of this invention. It is a figure which shows the modification of the to-be-driven part in the vibration type drive device of Example 1 of this invention. It is a figure which shows the result of having calculated the surface pressure distribution in the vibration type drive device of Example 1 of this invention. It is a figure which shows the modification of the to-be-driven part in the vibration type drive device of Example 2 of this invention. It is a figure which shows the drive state of the vibration part in the vibration type drive device of Example 2 of this invention. It is a figure which shows the other structural example of the to-be-driven part in the vibration type drive device of Example 2 of this invention. It is a figure which shows the structural example of the vibration type drive device in Example 3 of this invention. It is a figure which shows the structural example of the to-be-driven part in the vibration type drive device of Example 3 of this invention. It is a figure which shows the modification of the to-be-driven part in the vibration type drive device of Example 3 of this invention. It is a figure which shows the result of having calculated the surface pressure distribution in the vibration type drive device of Example 3 of this invention. It is a figure which shows the structural example of the vibration type drive device in Example 4 of this invention. It is a figure which shows the structural example of the to-be-driven part in the vibration type drive device of Example 4 of this invention. It is a figure which shows the modification of the to-be-driven part in the vibration type drive device of Example 4 of this invention. It is a figure which shows the result of having calculated the surface pressure distribution in the vibration type drive device of Example 4 of this invention. It is a figure which shows the structural example of the vibration type drive device in Example 5 of this invention. It is a figure which shows the structural example of the vibrating body in the vibration type drive device of Example 5 of this invention. It is a figure which shows the vibration type drive device in patent document 1. FIG. It is a figure which shows the result of having calculated surface pressure distribution by the structure similar to the structure in patent document 1. FIG. It is a figure explaining the state in which the elliptical orbit-like feed movement generate | occur | produces on the upper surface of a vibrating body with the vibration wave in the vibration type drive device of Example 1 of this invention. (A) is a figure which shows the structural example of the piezoelectric vibrator which has arrange | positioned several protrusion in Example 5 of this invention. (B-1) is a diagram showing one bending vibration mode of the two bending vibration modes of the piezoelectric vibrator, and (b-2) is the other bending vibration mode of the two bending vibration modes of the piezoelectric vibrator. FIG. (A) (b) is a figure explaining the preparation method of the to-be-driven part in Example 1 of this invention.

In the present invention, an electro-mechanical energy conversion element is attached, and a vibration part that vibrates when a drive voltage is applied to the electro-mechanical energy conversion element, and frictional contact through the vibration part and the contact part, And a driven part that moves relative to the vibrating part due to vibration of the vibrating part, wherein the contact part is provided by either the driven part or the vibrating part. Projecting on the other side, supported by two support parts made of a deformable and recoverable material, and the distance between the two support parts is larger than the width of the contact part supported by these support parts. A narrowing region is formed.
A material capable of deformation and restoration of the support portion of the present invention is required to have a certain spring property or elasticity. In the present invention, stainless steel can be used as the material of the support portion. Specifically, it is preferable to use SUS420J2. In addition, SUS440C, SUS420F, etc. which are martensite diameter SUS can be used.
As a manufacturing method of the support portion of the present invention, cutting or pressing can be used. And it is preferable to process a support part integrally by these processing methods. Moreover, it can also join, after processing a support part divided into several members, such as an outer side support part, an inner side support part, and a contact part. In addition, when machining the space surrounded by the contact part, the main ring part, and the support part, accurate machining is performed by using a tool having an arcuate blade that matches R of the support part. A mode for carrying out the present invention capable of creating a shape will be described by the following examples.

[Example 1]
As a first embodiment, a configuration example of a vibration type driving device to which the present invention is applied will be described.
FIG. 1A is a perspective view of the vibration type driving apparatus in the present embodiment, and FIG. 1B shows a cut model of the vibration type driving apparatus in the present embodiment.
Here, the vibration type driving apparatus of the present embodiment will be described first.
The vibration type driving apparatus of the present embodiment includes an oscillating portion that is attached with an electromechanical energy conversion element and vibrates when a driving voltage is applied to the electromechanical energy conversion element.
The driven portion that is in frictional contact with the vibrating portion via the contact portion is configured to move relative to the vibrating body by the vibration of the vibrating portion. Their specific configuration is shown in FIG.
In FIG. 1, 1 is a driven portion, 2 is a vibrating body (vibrating portion), 3 is an electro-mechanical energy conversion element, 4 is a pressure spring for bringing the driven portion into pressure contact with the vibrating body, 10 Is a drive shaft, and 11 is a vibrating body support portion for supporting the vibrating body.
The pressure spring 4 is formed in a thin plate shape, and is fixed to the drive shaft 10 in a state of being elastically deformed so that a reaction force is applied in the contacting direction, whereby the driven portion 1 and the vibrating body. 2 is in pressure contact.
Two alternating voltages are passed through the electromechanical energy conversion element 3 joined to the vibrator 2 with a predetermined phase difference, and a traveling vibration wave is generated in the vibrator comprising the vibrator 2 and the electromechanical energy conversion element 3. Exciting.
Due to this vibration wave, an elliptical orbit-like feeding motion is generated on the upper surface of the vibrating body 2 as shown in FIG.
By this feed movement, the driven part 1 that receives the pressure part (pressure spring) 4 and is in pressure contact with the vibrating body 2 is driven relative to the vibrating body 2.

FIG. 2 is a cross-sectional view of a driven portion of the vibration type driving device according to the present embodiment.
In FIG. 2, the driven part 1 includes a main ring part 5, two support parts including a first support part 6 and a second support part 7 made of a deformable and recoverable material, and these two support parts. And a contact portion 8 having a beam-like structure supported by the. In the present invention, the deformable / restorable material includes a material having springiness or elasticity.
A space portion 9 is formed between the two support portions and the main ring portion and allows the deformation of the two support portions to escape.
As shown in FIG. 2, the first support portion 6 and the second support portion 7 have a central portion of the contact portion 8 such that a part thereof is narrower than the width of the contact portion 8. It is comprised so that an arc may be drawn toward a direction.

In this way, by forming a region between the two support portions where the interval is narrower than the width of the contact portion supported by these support portions, the two support portions are mutually attached when pressurized. It can be transformed to approach.
That is, when the driven portion 1 is in pressure contact with the vibrating body 2 by the pressing portion 4, the two support portions 6 and 7 have small arc strings as shown in FIG. Deform to approach each other.
Due to this deformation, the connecting portion between the two support portions 6 and 7 and the contact portion 8 moves in a direction away from the vibrating body 2, so that a moment is generated in the directions of arrows A and B, and the contact portion 8 is The deformation becomes a convex shape in the direction of the vibrating body 2.
At this time, as shown in FIG. 4, the surface pressure at the contact portion between the driven portion 1 and the vibrating body 2 has a maximum value away from both ends, and the surface pressure is not zero even near the center. Therefore, the surface pressure can be dispersed over the entire surface of the contact portion 8. Here, a method for creating a driven part in the present embodiment will be described. As shown in FIG. 22, the main ring upper part 51, the main ring outer peripheral side lower part 52 formed integrally with the first support part 6, and the main ring inner part formed integrally with the second support part 7. The driven portion is configured by separately forming the circumferential lower portion 53 and the contact portion 8 by cutting and joining them. In addition to using an adhesive as a joining method, joining may be performed by metal brazing such as soldering, welding by laser or electric resistance heat, or the like. The upper part of the main ring and the contact part may be formed by pressing.

[Example 2]
As a second embodiment, a configuration example of a vibration type driving device having a different form from the first embodiment will be described.
FIG. 5 is a cross-sectional view of a driven portion of the vibration type driving device in the present embodiment, and the overall structure of the vibration type driving device is the same as that of the first embodiment.
In FIG. 5, since the thickness of the second support portion 7 is larger than the thickness of the first support portion 6 due to a deformable and recoverable material, the rigidity on the inner peripheral side is higher than the rigidity on the outer peripheral side. Yes.
FIG. 6 is a view of the deformation of the contact portion during vibration of the vibration portion of the vibration type driving device according to the present embodiment as viewed from a plane parallel to the radial direction.
As shown in FIG. 6, the vibration part and the driven part are formed in an annular shape, and the vibration part of the vibration type drive device has a vibration inclined in the axial direction around a certain point. The height differs between the inner peripheral side and the outer peripheral side.
Therefore, as in this embodiment, the difference in the rigidity of the contact part of the driven part between the inner peripheral side and the outer peripheral side makes the deformation amount on the outer peripheral side larger than the deformation amount on the inner peripheral side. It is possible to make a difference in the amount of displacement between the support portions on the inner peripheral side and the outer peripheral side.
As a result, the contact surface 8 is easily deformed along the contact surface of the vibrating body, so that the surface pressure can be more effectively dispersed.
In addition, as shown in FIG. 7, the rigidity of the inner peripheral side and the outer peripheral side is determined by making a difference in the diameter of the arc constituting the support portion between the inner peripheral side and the outer peripheral side, and making the shape different in size. A difference may be provided.

[Example 3]
As a third embodiment, a configuration example of a vibration type driving device having a different form from the above embodiments will be described.
FIG. 8A is a perspective view of the vibration type driving apparatus in the present embodiment, and FIG. 8B shows a cut model of the vibration type driving apparatus in the present embodiment.
FIG. 9 is a diagram showing the configuration of the driven portion of the vibration type driving device in this embodiment.
In FIG. 8, 13 is a driven part, 2 is a vibrating body, 3 is an electro-mechanical energy conversion element, and 12 is a pressure spring for bringing the vibrating body into pressure contact with the driven part. Reference numeral 14 denotes a vibrating body support portion that supports the vibrating body. Reference numeral 15 denotes a vibrating body support portion 14 that is supported by the vibrating body support portion 14 via a bearing 16 so as to receive the driven portion and rotate relative to the vibrating body support portion 14. Rotating part.
In this embodiment, the pressurizing part is a wave washer, but a spring such as a coil spring may be used.
The driven portion 13 is composed of a main ring portion 17, a first support portion 18 and a second support portion 19 made of a deformable and recoverable material, and a beam-like structure supported by these two support portions. The contact portion 20 is provided between the two support portions and the main ring portion. And the space part 21 for releasing the deformation | transformation of the said 2 support part is formed.
As shown in FIG. 9, one of the two support portions 18 and 19 is directed toward the center of the contact portion so that a part of the two support portions 18 and 19 is narrower than the width of the contact portion 20. It is configured to bend in a “reverse character” and the other in a “U” shape and face each other.

By adopting such a configuration, when the driven portion 13 is brought into pressure contact with the vibrating body 2 by the pressure portion 4, the two support portions 18 and 19 are moved as shown in FIG. The apex part is deformed so as to go to the contact part.
Due to this deformation, a moment is generated in the direction of arrows A and B at the connection portion between the two support portions 18 and 19 and the contact portion 20, and the contact portion 20 has a convex shape in the direction of the vibrating body 2. The deformation that becomes.
At this time, as shown in FIG. 11, the surface pressure at the contact portion between the driven portion 1 and the vibrating body 2 is the maximum value away from both ends, and the surface pressure is applied except at the center of the contact portion. Yes. As a result, the surface pressure can be dispersed over the entire surface of the contact portion 8.
As described above, by making the support portion linear, substantially the same effect can be obtained with a simpler structure than that of the first embodiment.
In addition, since the central portion of the motor can be opened by providing the pressing portion on the vibrating body side, a configuration suitable for driving an optical member such as a lens can be obtained.
In addition, in order to provide a difference in rigidity between the inner peripheral side and the outer peripheral side as in the second embodiment, a difference may be provided in the shape such as thickness and size.

[Example 4]
As a fourth embodiment, a configuration example of a vibration type driving device having a different form from the above embodiments will be described.
FIG. 12A is a perspective view of the vibration type driving apparatus in the present embodiment, and FIG. 12B shows a cut model of the vibration type driving apparatus in the present embodiment. FIG. 13 is a diagram showing the configuration of the driven portion of the vibration type driving device in this embodiment.
In FIG. 12, 22 is a driven part, 2 is a vibrating body, 3 is an electro-mechanical energy conversion element, 23 is a pressing part for pressing and contacting the driven part to the vibrating body, 24 is a drive shaft, Reference numeral 25 denotes a vibrating body support portion that supports the vibrating body.
The driven portion 22 includes a main ring portion 26, a first support portion 27 and a second support portion 28 made of a deformable and recoverable material, and a beam-like structure supported by these two support portions. The contact portion 29 is provided between the two support portions and the main ring portion. And the space part 30 for releasing the deformation | transformation of the said 2 support part is formed.
As shown in FIG. 13, the width L2 of the connecting portion of the contact portion 29 is larger than the width L1 of the connecting portion between the first support portion 27 and the second support portion 28 and the main ring portion 26. It is configured to be wider.

With such a configuration, when the driven portion 22 is in pressure contact with the vibrating body 2 by the pressure portion 23, the two support portions 27 and 28 are arc strings as shown in FIG. Deforms and approaches in the direction of decreasing.
And since the connection part of the said two support parts 27 and 28 and the said contact part 29 floats from the said vibrating body 2, a moment generate | occur | produces in the direction of the arrow A and B, and the said contact part 29 of the said vibrating body 2 exists. Deforms to become convex in the direction.
At this time, as shown in FIG. 15, the pressure distribution in the contact portion is wider than that in the previous example, and the surface pressure can be dispersed over a wide range.

Thus, the surface pressure can be dispersed by making the width of the contact portion wider than the width of the connection portion between the main ring portion and the two support portions.
Unlike Example 1 to Example 3, it is possible to omit the configuration of separating the two support parts again from the closest approach part of the two support parts, so it becomes possible to shorten the length of the two support parts, It can be set as the structure reduced in the thickness direction.
In addition, in order to provide a difference in rigidity between the inner peripheral side and the outer peripheral side as in the second embodiment, a difference in thickness and shape may be provided.
Further, as in the third embodiment, a spring may be provided on the surface of the vibrating body that faces the contact surface between the vibrating body and the driven portion.

[Example 5]
As a fifth embodiment, a configuration example of a vibration type driving device having a different form from the above embodiments will be described.
FIG. 16A is a perspective view of the vibration type driving apparatus in the present embodiment, and FIG. 16B shows a cut model of the vibration type driving apparatus in the present embodiment. FIG. 17 is a diagram showing the configuration of the contact portion of the vibrator of the vibration type driving device in the present embodiment.
In FIG. 16, 31 is a vibrating body, 32 is a driven part, 33 is an electromechanical energy conversion element, the driven part 32 is composed of a magnet, and the vibrating body 31 is a magnetic body. A pressing force by magnetic force acts between the driven part and the vibrating body.
Here, a basic driving configuration of the vibrator will be briefly described. FIG. 21A is a diagram showing a basic configuration of a piezoelectric vibrator equivalent to the one mounted in the present embodiment.
In this embodiment, there is one protrusion, but the driving principle is the same, and a plurality of protrusions may be arranged as shown in FIG. The details of the driving method are described in JP-A-2004-320846.

FIG. 21B is a diagram showing two bending vibration modes of the piezoelectric vibrator.
The vibration mode in FIG. 21 (b-1) represents one bending vibration mode (referred to as a feed mode) of the two bending vibration modes.
This feed mode is a secondary bending motion in the long-side direction (arrow X direction) of the rectangular vibrator 106, and has three nodes parallel to the short-side direction (arrow Y direction).
Here, the protrusion 108 is disposed in the vicinity of a position that becomes a node by the vibration in the feed mode, and the direction of the arrow X (= direction parallel to the surface on which the electro-mechanical energy conversion element is joined) by the vibration in the feed mode. Reciprocate at
Moreover, the vibration mode shown in FIG. 21 (b-2) represents the other bending vibration mode (called a push-up mode) of the two bending vibration modes.
This push-up mode is a primary bending vibration in the short-side direction (arrow Y direction) of the rectangular vibrating body 106, and has two nodes parallel to the long-side direction (arrow X direction).

Here, the nodes in the feed mode and the nodes in the push-up mode are substantially orthogonal in the XY plane.
In addition, the protrusion 108 is disposed in the vicinity of a position that becomes an antinode due to the vibration in the push-up mode, and the arrow Z direction (= direction perpendicular to the surface where the electro-mechanical energy conversion element is bonded) ) Reciprocate.
By generating the vibrations in the feed mode and the push-up mode described above with a predetermined phase difference, an elliptical motion is generated at the tip of the protrusion 108, and the arrow X direction (= electro-mechanical energy conversion element in FIG. 21 is joined). The driving force is given in a direction parallel to the surface. The vibrating body 31 is a protrusion comprising a diaphragm 34, a contact portion 37 with the driven portion, and two support portions 35 and 36 made of a deformable and recoverable material for supporting the contact portion in a beam shape. It consists of parts.
A space 38 is provided between the projection and the diaphragm to allow deformation of the two support portions.
As shown in FIG. 17, an arc is drawn toward the center of the contact portion 37 so that at least a part of the two support portions 35 and 36 is narrower than the width of the connection portion with the contact portion 37. It is configured as follows.
With such a configuration, it is possible to disperse the surface pressure in the contact portion 37 when the driven portion is brought into pressure contact as in the first embodiment.
In the present embodiment, the protrusion has the same shape as that of the first embodiment, but may have the same shape as that of the third and fourth embodiments. Moreover, it is good also as a structure which uses a spring as a pressurizing means.

In the present invention, as described above, the contact portion supported by the two support portions protruding from the driven portion or the vibration portion to the other side thereof is configured. When the vibrating part and the driven part come into pressure contact, the narrow region moves to the contact part side.
As a result, a moment in which the vicinity of the connection portion between the contact portion and the two support portions is separated from the contact portion acts, and the contact portion is deformed into a convex shape on the contact side, and the surface pressure is distributed throughout the contact portion. It becomes possible to make it.
In addition, the present invention can improve the durability of the vibration type drive device, particularly in a special environment, and therefore can be applied to all fields where the durability of the vibration type drive device (ultrasonic actuator) is required. Is possible.

1: Driven part 2: Vibrating body 3: Electro-mechanical energy conversion element 4: Pressurizing part (pressurizing spring)
5: Main ring part 6: First support part 7: Second support part 8: Contact part 9: Space part 10: Drive shaft 11: Vibration body support part

Claims (6)

A vibration unit attached with an electro-mechanical energy conversion element and vibrating when a drive voltage is applied to the electro-mechanical energy conversion element;
A vibration-type driving device having a driven portion that is in frictional contact with the vibration portion and the contact portion and moves relative to the vibration portion by vibration of the vibration portion;
The contact portion is supported by two support portions made of a material having a spring property, protruding from either the driven portion or the vibrating portion to the other side thereof,
A vibration type driving device characterized in that a region is formed between the two support portions, the interval of which is narrower than the width of the contact portion supported by these support portions.   The space part for releasing the deformation of the two support parts is formed between the driven part or the vibration part and the two support parts. Vibration type drive device. The vibrating portion and the driven portion are formed in an annular shape, and the contact portion is supported by the two support portions protruding from the driven portion toward the contact portion,
There is a difference in rigidity between the inner peripheral side and the outer peripheral side by making a difference in the thickness of the support portion between one support portion on the inner peripheral side and the other support portion on the outer peripheral side in the two support portions. The vibration type driving apparatus according to claim 1, wherein the vibration type driving apparatus is provided. The vibrating portion and the driven portion are formed in an annular shape, and the contact portion is supported by the two support portions protruding from the driven portion toward the contact portion,
There is a difference in rigidity between the inner peripheral side and the outer peripheral side by making a difference in the size of the support portion between one support portion on the inner peripheral side and the other support portion on the outer peripheral side in the two support portions. The vibration type driving apparatus according to claim 1, wherein the vibration type driving apparatus is provided. A region where the interval is narrower than the width of the contact portion,
The one of the two support parts is configured to be bent in a reverse shape in the direction of the central portion of the contact portion and the other in a reverse shape, and facing each other. The vibration type driving device according to claim 1 or 2. A region where the interval is narrower than the width of the contact portion,
The width of the connecting portion with the contact portion is wider than the width of the connecting portion with either one of the driven portion or the vibrating portion in the two support portions. The vibration type driving device according to claim 1 or 2.

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