JP2024000619A - Oscillatory wave driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillatory wave driving device capable of suppressing the generation of abnormal noise.

SOLUTION: The oscillatory wave driving device is for moving a transducer whose oscillation is excited by an electrical-mechanical energy conversion element and a friction member that is in contact with the transducer at a contact surface relatively in a first direction. The oscillatory wave driving device has: a holding member for holding the transducer; a pressurizing member for pressurizing the transducer in a second direction orthogonal to the contact surface; a support member for supporting the holding member displaceable in the second direction while limiting displacement in the first direction; and a viscoelastic member arranged between the holding member and the support member in the second direction.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a vibration wave drive device.

When driving a friction-driven vibration wave drive device (ultrasonic motor) whose drive source is deformation due to the piezoelectric effect of a piezoelectric element, a vibrator to which the piezoelectric element is bonded vibrates. Since the vibrator makes frictional contact with the friction member, vibrations caused by the frictional contact are transmitted to the vibrator in addition to the vibrations of the piezoelectric element. When this vibration is transmitted to the holding member that holds the vibrator, the vibration of the holding member generates abnormal noise, making it impossible to maintain quietness. Patent Document 1 discloses that in order to suppress vibration of the holding member in the pressing direction, the holding member, the holding member holding frame, and the pressing member are arranged at positions that do not overlap with the plurality of members when viewed from the pressing direction. A configuration is disclosed that includes a vibration damping member that contacts a plurality of members. Patent Document 2 discloses a configuration in which a vibration damping member is provided between a holding member and a surface of a holding member holding frame in a direction perpendicular to the pressing direction in order to suppress vibration in a direction perpendicular to the pressing direction of the holding member. is disclosed.

JP 2021-2967 Publication JP2019-126220A

However, in the configuration of Patent Document 1, damping is performed only by the damping force in the bending direction, so the vibration suppression effect is low and there is a risk that abnormal noise may occur. Further, in the configuration of Patent Document 2, the damping effect against a mode that vibrates in the pressurizing direction, which is a mode that mainly generates abnormal noise, is low, and there is a possibility that abnormal noise may be generated.

An object of the present invention is to provide a vibration wave drive device that can suppress the generation of abnormal noise.

A vibration wave drive device as one aspect of the present invention provides a vibration wave drive device that uses vibration waves to relatively move a vibrator whose vibration is excited by an electro-mechanical energy conversion element and a friction member that contacts the vibrator at a contact surface in a first direction. The drive device includes a holding member that holds the vibrator, a pressure member that presses the vibrator in a second direction perpendicular to the contact surface, and a pressurizing member that presses the vibrator in a second direction while limiting displacement in the first direction. The device is characterized in that it has a support member displaceably supported in the second direction, and a viscoelastic member disposed between the holding member and the support member in the second direction.

According to the present invention, it is possible to provide a vibration wave drive device that can suppress the generation of abnormal noise.

1 is a perspective view of a vibration wave drive device of Example 1. FIG. FIG. 3 is a cross-sectional view of a driving force extraction section of the vibration wave drive device according to the first embodiment. 1 is an exploded perspective view of the vibration wave drive device of Example 1. FIG. 1 is a cross-sectional view in the X-axis direction of the vibration wave drive device of Example 1. FIG. FIG. 3 is an explanatory diagram of a holding member, a holding member holding frame, and a viscoelastic member in Example 1. FIG. FIG. 3 is a perspective view of a holding member and a holding member holding frame of Example 1. FIG. FIG. 3 is a diagram of the vibration wave drive device of Example 1 viewed from the positive direction of the Y-axis. FIG. 7 is an explanatory diagram of a retaining member, a retaining member holding frame, and a viscoelastic member in Example 2; FIG. 7 is a perspective view of a holding member and a holding member holding frame of Example 2; FIG. 7 is a perspective view of a holding member and a convex portion provided on a holding member holding frame of Example 2; FIG. 7 is an explanatory diagram of a holding member, a holding member holding frame, and a viscoelastic member in Example 3; FIG. 7 is a perspective view of a holding member and a holding member holding frame of Example 3; FIG. 7 is an explanatory diagram of a holding member, a holding member holding frame, and a viscoelastic member in Example 4. FIG. 7 is a perspective view of a holding member and a holding member holding frame of Example 4;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to the same members, and duplicate explanations will be omitted.

The vibration wave drive device of each embodiment is suitable for, for example, a digital single-lens reflex camera with interchangeable lenses, a digital still camera, a digital video camera, a digital video camera with interchangeable lenses, and the like.

In each example, the direction of relative movement of the vibrator and the friction member is the X-axis direction (drive direction, first direction), the direction perpendicular to the X-axis, and the direction in which the vibrator is pressed against the friction member (pressing direction). ) is the Y-axis direction (second direction), and the direction perpendicular to the X-axis direction and the Y-axis direction is the Z-axis direction. The Y-axis direction is perpendicular to the contact surface of the friction member with the vibrator. Further, in each axis, the direction of the arrow is defined as a positive direction, and the direction opposite to the direction of the arrow is defined as a negative direction. In each example, the pressing direction is the positive direction of the Y axis. Note that the coordinate system in each embodiment is for convenience of explanation, and the present invention is not limited thereto.

1 to 4 are a perspective view, a sectional view of a driving force extraction section, an exploded perspective view, and a sectional view in the X-axis direction of the vibration wave drive device 100 of this embodiment, respectively.

The vibration wave drive device 100 is a direct-acting type linear actuator that generates a driving force in the X-axis direction. A connecting groove portion 17a provided in the driven portion 17 is connected to the protrusion-shaped driving force extraction portion 16a shown in FIG. 2 in a state where it is biased by a spring (not shown). The vibration wave driving device 100 can move the driven portion 17 in the X-axis direction.

First, the mechanism by which the vibration wave drive device 100 generates the driving force will be explained. As shown in FIG. 3, the vibration wave drive device 100 is composed of a piezoelectric element (electrical-mechanical energy conversion element) 1 and a boss plate 2, which are fixed to each other with an adhesive or the like, and vibrations are excited by the piezoelectric element 1. It has a vibrator 3. The flexible substrate 12 is mechanically and electrically connected to the piezoelectric element 1 using an anisotropic conductive paste or the like. The piezoelectric element 1 is provided with two divided electrodes. By applying two-phase high-frequency voltages having a temporal phase difference of π/2 to the two electrodes, an elliptical motion is generated in the protrusion 2a of the boss plate 2 shown in FIG. 4. At this time, by changing the frequency and phase difference of the high-frequency voltage applied to the piezoelectric element 1, the rotation direction and ellipse ratio of the ellipse can be changed as appropriate. Therefore, the vibrator 3 moves relative to the friction member 14 by frictionally contacting the friction member 14 fixed to the base member 13 and performing an elliptical motion due to the pressing force from the pressure plate 8. Generate driving force. That is, the vibrator 3 moves relative to the friction member 14 in the X-axis direction.

Next, a structure for transmitting the pressurizing force from the pressurizing plate 8 to the vibrator 3 will be explained. The pressing force is generated by the pressing plate 8, the tension coil spring 7, the felt 5, the transmission member 6, and the move plate 16. In the stretched state, the tension coil spring 7 has a first end connected to the move plate 16 and a second end connected to the pressure plate 8, and generates a pressure force in the direction of contraction. The generated pressing force acts on the vibrator 3 via the felt 5 and the transmission member 6.

Next, the connection of the vibrator 3, the holding member 4 that holds the vibrator 3, and the holding member holding frame (supporting member) 11 will be explained. As shown in FIGS. 3 and 4, the boss plate 2 is formed with two holes 2b spaced apart in the X-axis direction. The holding member 4 includes fixing pins 4a inserted into the two holes 2b. After the pin 4a is inserted into the hole 2b, it is fixed with an adhesive or the like. The holding member holding frame 11 is connected to the move plate 16 by screws 20 and engages with the holding member 4. The holding member holding frame 11 supports the holding member 4 so that it can be displaced in the Y-axis direction while limiting displacement in the X-axis direction.

At each end of the holding member 4 in the X-axis direction, the holding member 4 is placed on the inside with the roller member 9 in between, and the holding member holding frame 11 is placed on the outside. The plate spring 10 is fixed to the holding member holding frame 11 by adhesive or the like, and urges the holding member 4 in the X-axis direction via the roller member 9. Thereby, the roller member 9 elastically urges the holding member 4 in the X-axis direction. That is, the holding member 4 is urged against the holding member holding frame 11 via the roller member 9. The holding member 4 is not only urged in the X-axis direction with respect to the holding member holding frame 11, but also movable in the Y-axis direction by rolling of the roller member 9. With this configuration, the holding member 4 has a degree of freedom of movement in the Y-axis direction and a degree of freedom of tilting around the Z-axis with respect to the holding member holding frame 11.

With the above configuration, the holding member 4 and the holding member holding frame 11 have no play in the X-axis direction, which is the driving direction, and almost no sliding resistance occurs in the Y-axis direction due to the rolling action of the roller member 9. It is possible to realize connections that do not require

In the holding member 4, almost no sliding resistance occurs in the Y-axis direction, so if excitation occurs due to vibrations from other members, for example, vibrations around the Z-axis in the direction of the arrow shown in FIG. 4 are unnecessary. Vibration is likely to occur. Therefore, in this embodiment, a viscoelastic member 19 such as a rubber material or a gel material is arranged between the holding member 4 and the holding member holding frame 11 in the Y-axis direction. Thereby, the holding member holding frame 11 and the viscoelastic member 19 play the role of a damper, and unnecessary vibrations of the holding member 4 can be suppressed.

Hereinafter, the arrangement location of the viscoelastic member 19 and its effects will be explained.

FIGS. 5A and 5B are an exploded perspective view and a view from the negative direction of the X-axis of the holding member 4, the holding member holding frame 11, and the viscoelastic member 19, respectively. 6(a) and 6(b) are perspective views of the holding member 4 and the holding member holding frame 11, respectively. The holding member 4 and the holding member holding frame 11 each include a surface (first surface, third surface) 4b and a surface (second surface, fourth surface) 11a that face each other. Viscoelastic member 19 is arranged between surfaces 4b and 11a.

Next, vibration suppression of the holding member 4 will be explained with reference to FIG. FIG. 7 is a diagram of the vibration wave drive device 100 of this embodiment viewed from the positive direction of the Y-axis. The holding member holding frame 11 is fastened to the move plate 16 with screws 20. The move plate 16 engages with the ball base 15 via three ball members 18 (rolling members). The ball base 15 is fastened to the base member 13 with screws 21. The base member 13 is fastened to the lens barrel with screws (not shown). Since the move plate 16 fastened with the screws 20 engages with the ball base 15 via the three ball members 18, the degree of freedom of the holding member holding frame 11 is restricted in the Y-axis direction and the rotational direction around the Z-axis. .

With the above configuration, by disposing the viscoelastic member 19 between the holding member 4 and the holding member holding frame 11, when the holding member 4 attempts to displace in the Y-axis direction or the rotational direction around the Z-axis, the holding member The holding frame 11 and the viscoelastic member 19 serve as a damper. Thereby, vibration of the holding member 4 can be suppressed.

In the configuration of Patent Document 1, the contact areas of the vibration damping member and other members do not overlap when viewed from the Y-axis direction. In such a configuration, for example, with respect to vibrations around the Z axis shown in FIG. It is difficult to suppress vibrations around the shaft. On the other hand, in this embodiment, the viscoelastic member 19 is arranged between the surfaces 4b and 11a that are formed to face each other in the Y-axis direction, as shown in FIGS. 4 and 5. That is, in this embodiment, when viewed from the Y-axis direction, at least a part of the contact point between the holding member 4 and the viscoelastic member 19 is the same as the contact point between the holding member holding frame 11 and the viscoelastic member 19. at least partially overlap. The space between the surfaces 4b and 11a is the same position in the X-axis direction as the positions of both ends of the holding member 4 in the X-axis direction, and is a position where vibrational displacement around the Z-axis is large. As a result, damping in the pressurizing direction can be applied at positions where vibrational displacement around the Z-axis is large, so that vibrations around the Z-axis can be effectively suppressed.

Note that if a large amount of unnecessary force in the Y-axis direction is applied to the vibrator 3, the pressure transmitted from the pressure plate 8 to the vibrator 3 is likely to be inhibited, resulting in deterioration of drive characteristics and damage to the piezoelectric element 1 and boss plate. Problems such as adhesive peeling described in No. 2 may occur. Therefore, in order to reduce the reaction force in the Y-axis direction from the viscoelastic member 19, it is preferable to use a material with low hardness for the viscoelastic member 19. For example, butyl rubber or the like may be used as the viscoelastic member 19.

The vibration wave drive device of this embodiment has the same basic configuration as the vibration wave drive device 100 of the first embodiment. In this embodiment, only the different configurations from the first embodiment will be explained, and the explanation of the same configurations will be omitted.

8(a) and 8(b) are diagrams showing a part of an exploded perspective view and a cross-sectional view of the XY plane of the holding member 42, the holding member holding frame (supporting member) 112, and the viscoelastic member 192, respectively. be. The holding member 42 and the holding member holding frame 112 each include a surface (first surface) 42a and a surface (second surface) 112a that face each other. The surfaces 42a are formed at both ends of the holding member 42 in the X-axis direction. Viscoelastic member 192 is disposed between surfaces 42a and 112a. In this embodiment, for example, butyl rubber or the like is used as the viscoelastic member 19.

9(a) and 9(b) are perspective views of the holding member 42 and the holding member holding frame 112, respectively. A convex portion (first convex portion) 42b having a pointed tip is provided on the surface 42a. A convex portion (second convex portion) 112b having a pointed tip is provided on the surface 112a. In this embodiment, the convex portions 42b and 112b have conical tips. The protrusions 42b and 112b are provided so as to bite into the viscoelastic member 192. As a result, the wedged convex portion 112b and the viscoelastic member 192 play the role of a damper, suppressing vibrations of the holding member 42. Furthermore, since the convex portion 42b bites into the viscoelastic member 192, a damping effect is exerted not only on vibrations in the Y-axis direction, such as vibrations around the Z-axis, but also on translational vibrations in the X-axis direction. Ru.

In this embodiment, the holding member 42 and the holding member holding frame 112 are configured such that the convex portions 42b, 112b abut against the viscoelastic member 192. Therefore, the reaction force in the Y-axis direction received from the viscoelastic member 192 can be made smaller than in surface contact, and the pressing force applied to the vibrator 3 is less likely to be inhibited.

The convex portions 42b are provided at two positions in the X-axis direction, as shown in FIG. Three protrusions 42b are provided at each position. The same applies to the convex portion 112b. As shown in FIG. 10, the convex portions 42b and 112b are provided so as not to overlap when viewed from the Y-axis direction. Thereby, even if the amount of bite of the convex portions 42b, 112b changes due to component tolerances, the viscoelastic member 192 can be deformed in the plane direction (the positive direction and the negative direction of the Y axis) as the deformable portion 192a. Therefore, the pressing force can be dispersed and the reaction force can be reduced.

The vibration wave drive device of this embodiment has the same basic configuration as the vibration wave drive device 100 of the first embodiment. In this embodiment, only the different configurations from the first embodiment will be explained, and the explanation of the same configurations will be omitted.

11(a) and 11(b) are diagrams showing a part of an exploded perspective view and a cross-sectional view of the XY plane of the holding member 43, the holding member holding frame (supporting member) 113, and the viscoelastic member 193, respectively. be. The holding member 43 and the holding member holding frame 113 each include a surface (first surface) 43a and a surface (second surface) 113a that face each other. Viscoelastic member 193 is arranged between surfaces 43a and 113a. In this embodiment, for example, as the viscoelastic member 193, a substance (material) having high fluidity such as gel and hardening through a chemical reaction is used.

12(a) and 12(b) are perspective views of the holding member 43 and the holding member holding frame 113, respectively. The surface 43a is the bottom surface of the recess 43b provided in the holding member 43. The viscoelastic member 193 is arranged in the recess 43b. A convex portion 113b is formed on the surface 113a. In this embodiment, the convex portion 113b bites into the viscoelastic member 193 from an oblique direction with respect to the Y axis. When configured to bite perpendicularly to the Y-axis, the reaction force from the viscoelastic member 193 has a large damping effect against vibrations in the Y-axis direction; Since the only damping effect is due to the frictional force of the elastic member 193, the effect is small. In this embodiment, since it bites into the viscoelastic member 193 at an angle with respect to the Y-axis, a reaction force from the viscoelastic member 193 acts against vibrations in the X-axis direction, making it possible to increase the damping effect. Thereby, the biting convex portion 113b and the viscoelastic member 193 play the role of a damper, and vibration of the holding member 43 can be suppressed. Furthermore, since the convex portion 113b bites into the viscoelastic member 193 from an oblique direction with respect to the Y-axis, it not only damps vibrations in the Y-axis direction such as vibrations around the Z-axis, but also damps translational vibrations in the X-axis direction. It can also exert a damping effect against Note that the holding member 43 may be provided with a convex portion, and the holding member holding frame 113 may be provided with a recessed portion.

In this example, the viscoelastic member 193 is injected from the outside after the vibration wave drive device 100 of Example 1 is assembled to the motor state and the pressure applied to the vibrator 3 is set, and then hardened. As a result, the extra pressure from the convex portion 113b does not act on the viscoelastic member 193, so no reaction force is generated in the Y-axis direction from the viscoelastic member 193, and the pressure applied to the vibrator 3 is not inhibited. Further, even if the dimensions change due to component tolerances, the viscoelastic member 193 and the convex portion 113b stably play the role of a damper, so that vibrations of the holding member 43 can be damped. Although the viscoelastic member 193 may be injected after assembly, the viscoelastic member 193 may be injected in advance and cured after assembly.

The vibration wave drive device of this embodiment has the same basic configuration as the vibration wave drive device 100 of the first embodiment. In this embodiment, only the different configurations from the first embodiment will be explained, and the explanation of the same configurations will be omitted.

In Examples 1 to 3, the viscoelastic member is provided at the longitudinal end of the holding member, but in this embodiment, it is provided at the lateral end of the holding member.

13(a) and 13(b) are an exploded perspective view and a cross-sectional view on the YZ plane of the holding member 44, the holding member holding frame (supporting member) 114, and the viscoelastic member 194, respectively. The holding member 44 and the holding member holding frame 114 each include a surface (first surface) 44a and a surface (second surface) 114a that face each other. Viscoelastic member 194 is disposed between surfaces 44a and 114a. In this embodiment, for example, butyl rubber or the like is used as the viscoelastic member 194.

14(a) and 14(b) are perspective views of the holding member 42 and the holding member holding frame 112, respectively. In this embodiment, the surfaces 44a are provided on two sides of the holding member 44 parallel to the X-axis direction. The viscoelastic members 194 are provided on two sides of the holding member 44 parallel to the X-axis direction. As a result, the holding member holding frame 114 and the viscoelastic member 194 play the role of a damper, and can exert a strong damping effect not only against vibrations in the Y-axis direction but also against rotational vibration modes around the X-axis.

Further, by forming the surfaces 44a and 114a in the shapes shown in the second embodiment and the third embodiment, the influence of the reaction force from the viscoelastic member 194 can be suppressed.

The disclosure of this embodiment includes the following configurations.
(Configuration 1)
A vibration wave drive device that relatively moves in a first direction a vibrator whose vibration is excited by an electro-mechanical energy conversion element and a friction member that contacts the vibrator at a contact surface,
a holding member that holds the vibrator;
a pressing member that presses the vibrator in a second direction perpendicular to the contact surface;
a support member that restrains the holding member in the first direction and the second direction;
A vibration wave drive device comprising: a viscoelastic member disposed between the holding member and the supporting member in the second direction.
(Configuration 2)
The holding member and the supporting member each include a first surface and a second surface facing each other,
The vibration wave drive device according to configuration 1, wherein the viscoelastic member is disposed between the first surface and the second surface.
(Configuration 3)
The holding member and the supporting member each include a third surface and a fourth surface facing each other,
The vibration wave drive device according to configuration 2, wherein the viscoelastic member is disposed between the third surface and the fourth surface.
(Configuration 4)
When viewed from the second direction, at least a portion of the contact point between the holding member and the viscoelastic member overlaps with at least a portion of the contact point between the support member and the viscoelastic member. A vibration wave drive device according to any one of features 1 to 3.
(Configuration 5)
4. The vibration wave drive device according to any one of configurations 1 to 3, wherein at least one of the holding member and the support member includes a convex portion that bites into the viscoelastic member.
(Configuration 6)
The vibration wave drive device according to configuration 5, wherein the convex portion has a conical tip.
(Configuration 7)
The holding member includes a first convex portion that bites into the viscoelastic member,
The support member includes a second convex portion that bites into the viscoelastic member,
7. The vibration wave drive device according to any one of configurations 1 to 6, wherein the first convex portion and the second convex portion do not overlap when viewed from the second direction.
(Configuration 8)
7. The vibration wave drive device according to configuration 5 or 6, wherein the convex portion is formed at an angle with respect to the second direction.
(Configuration 9)
9. The vibration wave drive device according to any one of configurations 1 to 8, wherein the viscoelastic member is disposed at a longitudinal end of the holding member.
(Configuration 10)
9. The vibration wave drive device according to any one of configurations 1 to 8, wherein the viscoelastic member is disposed at an end in the transverse direction of the holding member.
(Configuration 11)
11. The vibration wave drive device according to any one of configurations 1 to 10, wherein the viscoelastic member is a rubber material.
(Configuration 12)
11. The vibration wave drive device according to any one of configurations 1 to 10, wherein the viscoelastic member is a gel material.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

1 Piezoelectric element (electrical-mechanical energy conversion element)
3 Vibrator 4 Holding member 8 Pressure plate (pressure member)
11 Holding member holding frame (supporting member)
14 Friction member 19 Viscoelastic member 100 Vibration wave drive device

Claims (12)

A vibration wave drive device that relatively moves in a first direction a vibrator whose vibration is excited by an electro-mechanical energy conversion element and a friction member that contacts the vibrator at a contact surface,
a holding member that holds the vibrator;
a pressing member that presses the vibrator in a second direction perpendicular to the contact surface;
a support member that supports the holding member so as to be movable in the second direction while limiting displacement in the first direction;
A vibration wave drive device comprising: a viscoelastic member disposed between the holding member and the supporting member in the second direction. The holding member and the supporting member each include a first surface and a second surface facing each other,
The vibration wave drive device according to claim 1, wherein the viscoelastic member is arranged between the first surface and the second surface. The holding member and the supporting member each include a third surface and a fourth surface facing each other,
The vibration wave drive device according to claim 2, wherein the viscoelastic member is arranged between the third surface and the fourth surface. When viewed from the second direction, at least a portion of the contact point between the holding member and the viscoelastic member overlaps with at least a portion of the contact point between the support member and the viscoelastic member. The vibration wave drive device according to claim 1 or 2. The vibration wave drive device according to claim 1 or 2, wherein at least one of the holding member and the supporting member includes a convex portion that bites into the viscoelastic member. The vibration wave drive device according to claim 5, wherein the convex portion has a conical tip. The holding member includes a first convex portion that bites into the viscoelastic member,
The support member includes a second convex portion that bites into the viscoelastic member,
The vibration wave drive device according to claim 1 or 2, wherein the first convex portion and the second convex portion do not overlap when viewed from the second direction. The vibration wave drive device according to claim 5, wherein the convex portion is formed at an angle with respect to the second direction. The vibration wave drive device according to claim 1 or 2, wherein the viscoelastic member is arranged at a longitudinal end of the holding member. The vibration wave drive device according to claim 1 or 2, wherein the viscoelastic member is arranged at an end in the transverse direction of the holding member. The vibration wave drive device according to claim 1 or 2, wherein the viscoelastic member is a rubber material. The vibration wave drive device according to claim 1 or 2, wherein the viscoelastic member is a gel material.