JP7094799B2 - Vibration type motor and drive - Google Patents

Description

The present invention relates to a vibration type motor and a drive device using the vibration type motor.

The vibration type motor is a motor that has the characteristics of high output and quietness while being relatively small, and is used for driving an optical lens in an image pickup device such as a camera, for example.

In the form of a vibration type motor, a vibrator provided with a plurality of protrusions is vibrated to cause an elliptical motion at the tip of the protrusions, and a driving force is generated between the protrusions and a friction member that frictionally slides to generate a driven body. There is a form to drive.

In the vibration type motor of such a form, it is preferable to make the surface pressure in contact with the friction member uniform at each protrusion in order to suppress drive unevenness such as a direction difference.

Patent Document 1 proposes a mechanism in which a pressurizing transmission mechanism to a vibrator is composed of a plurality of members that can rotate with each other in order to make the surface pressure of each protrusion uniform.

Japanese Unexamined Patent Publication No. 2017-200400

In the vibration wave motor described in Patent Document 1, the tilt of the vibrator holding mechanism and the pressurizing mechanism is configured so as not to give an unnecessary moment to the vibrator, whereby the surface pressure of the protrusion of the vibrator is made uniform. ing. However, even if the cushioning member arranged between the transmission member and the oscillator in the pressurizing mechanism is biased and crushed, drive unevenness may occur. In order to prevent the cushioning member from being biased and crushed, it is preferable that the transmission member in contact with the cushioning member tilts following the oscillator or the oscillator holding member that holds the oscillator.

However, in the vibration wave motor described in Patent Document 1, the transmission member and the oscillator holding member are formed of a thin member in order to reduce the thickness. Therefore, if the positioning portion of the transmission member in contact with the cushioning member is provided at the end in the driving direction so that the transmission member can easily follow the vibrator or the vibrator holding member due to the contact and friction of the positioning portion, the positioning portion is sufficient. It is difficult to obtain a large amount of friction. In order to obtain a sufficient amount of hooking, it is necessary to increase the thickness of the parts around the positioning portion, and it is difficult to achieve both thinning and thinning.

Therefore, an object of the present invention is to provide a vibration type motor which is compact and suppresses drive unevenness.

In order to achieve the above object, the vibration type motor according to the present invention has a vibrator and a friction member in contact with the vibrator, and the vibrator and the friction member are vibrated by vibrating the vibrator. A vibration type motor that relatively moves the vibrator, a holding member that holds the vibrator, a pressure member that generates a pressure to press the vibrator on the friction member, and a third member that transmits the pressure. It has one transmission member and a second transmission member arranged between the vibrator and the first transmission member, and the first transmission member transmits to the second transmission member. A notch or a hole is provided at a position shifted in the moving direction in which the vibrator and the friction member move relative to the pressurizing center of the pressing force that presses the vibrator against the friction member. The holding member is provided with a portion notched by the notch or a protrusion arranged in the hole, and the second transmission member is provided with a contact portion that comes into contact with the protrusion. It is characterized by being.

According to the present invention, it is possible to provide a vibration type motor which is compact and suppresses drive unevenness.

An exploded perspective view of the vibration type motor according to the embodiment of the present invention. The figure which shows the assembly state of the vibration type motor which concerns on embodiment of this invention. The figure which shows the drive characteristic of a vibration type motor The figure explaining the structure which does not cause bias in the collapse of the cushioning member in the vibration type motor which concerns on embodiment of this invention. The figure explaining the application example to the lens drive device of the vibration type motor which concerns on embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described. 1 and 2 are views showing the vibration type motor 1 according to the embodiment of the present invention. 1 is an exploded perspective view of the vibrating motor 1, FIG. 1A is a view of the vibrating motor 1 from above, and FIG. 1B is a view of the vibrating motor 1 from below. .. 2A and 2B are views showing an assembled state of the vibrating motor 1, FIG. 2A is a view of the vibrating motor 1 from above, and FIG. 2B is a view of the vibrating motor 1 from below. It is a figure. In this embodiment, the vibrator 111 side is the upper side and the friction member 113 side is the lower side in the direction in which the vibrator 111 and the friction member 113 overlap.

The oscillator 111 has a structure in which, for example, a plate-shaped piezoelectric element 111a and an elastic member 111b having two protrusions 111c are attached. The piezoelectric element 111a is, for example, PZT (lead zirconate titanate), and the elastic member 111b is, for example, a metal plate. When an appropriate AC voltage is applied to the piezoelectric element 111a, an elliptical motion can be generated at the tip of the protrusion 111c. The oscillator holding member 112 is, for example, a resin frame, and holds the oscillator 111 by being directly adhered to the oscillator 111. A flexible substrate, which is a power feeding member 126, is attached to the piezoelectric element 111b, and an AC voltage is applied to the piezoelectric element 111b via the flexible substrate.

The friction member 113 is, for example, a metal plate, and is in frictional contact with the protrusion 111c of the vibrator 111 on the sliding surface 113a. Further, the friction member 113 is screw-fixed to the motor housing 124. In the present embodiment, the vibrator 111 moves with respect to the friction member 113 by generating an elliptical motion at the tip of the protrusion 111c, and the movement direction of the vibrator 111 is parallel to the D1 direction. The structure may be such that the vibrator 111 and the friction member 113 move relative to each other by vibrating the vibrator 111, and the friction member 113 may move with respect to the vibrator 111.

The pressurizing member 114 is, for example, four tension springs, which are arranged around the movable frame 118. Each of the pressurizing members 114 generates a tensile force, and the resultant force presses the vibrator 111 in the pressurizing direction (D2 direction) by the pressing force (F1).

The first transmission member 115 and the second transmission member 116 are, for example, metal plates. The second transmission member 116 is arranged between the oscillator 111 and the first transmission member 115. A pressure member 114 is attached to the first transmission member 115, and a cushioning member 117 is attached to the second transmission member 116. The cushioning member 117 is made of a material such as felt that does not easily hinder the vibration of the oscillator 111 even if it comes into contact with the oscillator 111. A ball protrusion 115a is arranged on the first transmission member 115, and the ball protrusion 115a abuts on the second transmission member 116. As a result, the second transmission member 116 is held so as to be relatively rotatably around the spherical protrusion 115a with respect to the first transmission member 115. The first pressurizing member 115 transmits the force generated by the pressurizing member 114 to the second transmission member 116, and the second pressurizing member transmits the pressurizing force (F1) to the vibrator 111 via the cushioning member 117. do.

The movable frame 118 is a resin frame body arranged so as to surround the periphery of the vibrator holding member 112. A rolling roller 119 is arranged between the movable frame 118 and the vibrator holding member 112, and the urging spring 120 urges the rolling roller 119 toward the vibrator holding member 112. The urging force of the urging spring 120 suppresses play between the movable frame 118 and the vibrator holding member 112 in the moving direction of the vibrator 111.

The movable guide member 121 and the fixed guide member 122 are, for example, metal plates. The movable guide member 121 is fixed to the movable frame 118 and has a guide groove 121a extending in the moving direction of the vibrator 111. Further, the fixed guide member 122 has a guide groove 122a and a guide surface 122b at a position facing the guide groove 121a, and the rolling ball 123 is sandwiched between the guide groove 122a, the guide surface 122b and the guide groove 121a. Guides the oscillator 111 in a direction parallel to the D1 direction. The fixing guide member 122 is fixed to the motor housing 124 by screws or a fixing plate 125.

Summarizing the above, the pressurizing member 114, the first transmission member 115, the second transmission member 116, and the cushioning member 117 generate a pressing force F1 that pressurizes the vibrator 111 against the friction member 113 and transmits the pressure to the vibrator 111. Functions as a pressurizing mechanism. Further, the movable frame 118, the rolling roller 119, the urging spring 120, the movable guide member 121, the fixed guide member 122, and the rolling ball 123 guide the vibrator 111 so as to be relatively movable with respect to the friction member 113. Functions as a holding mechanism for.

Next, the drive unevenness of the vibration type motor will be described. FIG. 3 is a diagram showing the drive characteristics of the vibration type motor, and FIG. 3A shows the drive characteristics when the surface pressure of the protrusion 111c of the vibrator 111 is uniform and the cushioning member 117 is biased and crushed. ing. On the other hand, FIG. 3B shows the driving characteristics when the surface pressure of the protrusion 111c of the vibrator 111 is uniform and the crushing of the cushioning member 117 is not biased. The vibration type motor 1 amplifies the elliptical motion of the protrusion 111c by utilizing the resonance of the vibrator 111, and controls the drive speed by the frequency (vibration frequency) of the AC voltage applied to the piezoelectric element 111a. The solid lines in FIGS. 3A and 3B represent the speed of the vibrator 111 in the D1 direction with respect to the vibration frequency, and the broken line in the figure indicates the D1 direction of the vibrator 111 with respect to the vibration frequency. Represents the speed in the opposite direction.

When the cushioning member 117 is biased and crushed, there is a difference in drive speed as shown by ΔV in FIG. 3A, whereas when the cushioning member 117 is crushed without bias, FIG. 5B is shown. As shown by ΔV in the middle, the direction difference of the driving speed can be suppressed.

In the vibration type motor 1 of the present embodiment, for example, when the movable frame 118 is tilted with respect to the vibrator 111, the tilt of the movable frame 118 is absorbed by the rolling of the rolling roller 119, and the vibrator holding member 112 and the vibrator are used. Unnecessary moments are not transmitted to 111. As a result, the surface pressure of the protrusion 111c of the vibrator 111 is kept uniform. Further, for example, when the tensile force generated by the pressure member 114 varies and the first transmission member 115 is tilted, the first transmission member 115 and the second transmission member 116 rotate relatively. Therefore, the inclination of the first transmission member 115 is absorbed, and unnecessary moments are not transmitted to the second transmission member 116, the cushioning member 117, and the oscillator 111. As a result, the surface pressure of the protrusion 111c of the vibrator 111 is kept uniform.

The configuration in which the crushing of the cushioning member 117 in the vibration type motor 1 of the present embodiment is not biased will be described in detail below.

FIG. 4 is a diagram illustrating a configuration that does not cause bias in the collapse of the cushioning member 117 in the vibration type motor 1. 4 (a) is a view of the movable part of the vibration type motor 1 viewed from above, and FIG. 4 (b) is a view in which the pressure member 114 and the transmission member 115 are hidden from FIG. 4 (a). 4 (c) is a sectional view taken along the line AA of FIG. 4 (a).

In FIG. 4A, the first transmission member 115 has a notch portion 115a at a position deviated from the pressurizing center P1 in a direction parallel to the direction D1 when viewed from above. Further, the oscillator holding member 112 has a protruding portion 112a arranged in a portion notched by the notched portion 115a.

Further, in FIG. 4B, the second transmission member 116 has a convex positioning portion 116a (contact portion) in the vicinity of the end portion in the moving direction of the vibrator 111. The contact between the positioning portion 116a and the protruding portion 112a determines the position of the second transmission member 116 with respect to the vibrator holding member 112 in the moving direction of the vibrator 111.

For example, when the first transmission member 115 is tilted as shown by M1 in FIG. 4C due to an impact from the outside, the spherical protrusion 115a of the first pressurizing member 115 rotates and the second transmission member 115. As shown by M2, 116 tilts and a frictional force F2 is generated. If the second transmission member 116 is tilted as shown by M2 due to the frictional force F2, the cushioning member 117 may be biased and crushed, resulting in drive unevenness as shown in FIG. 3A.

As described above, in the vibration type motor 1 of the present embodiment, when the first transmission member 115 tilts and the frictional force F2 is generated as shown by M1, the second transmission member 116 moves from the pressurizing center P1 to the direction D1. It is in contact with the oscillator holding member 112 at a point P2 displaced in the parallel direction. At this time, the force that the second transmission member 116 urges the oscillator holding member 112 in the direction parallel to the direction D1 is defined as the urging force F3. Then, at the point P2, a frictional force F4 corresponding to the urging force F3 acts between the second transmission member 116 and the vibrator holding member 112.

Therefore, the movement of the second transmission member 116 and the cushioning member 117 tilting in the direction indicated by M2 is suppressed by the frictional force F4. Since the positioning portion 116a of the second transmission member 116 is provided at the end of the vibrator 111 in the moving direction, a larger frictional force F4 acts on the rotation in the direction indicated by M2.

With such a configuration, the posture of the second transmission member 116 easily follows the vibrator holding member 112, so that the cushioning member 117 is prevented from being biased and crushed, and the drive unevenness as shown in FIG. 3 (b) is prevented. Suppressed drive characteristics can be obtained.

Further, in the vibration type motor 1, the vibrator holding member 112 is provided with a protruding portion 112a extending in the vertical direction to sufficiently secure the engagement amount L1 of the positioning portion 116a of the second transmission member 116. In the thin vibration type motor 1, both the oscillator holding member 112 and the second transmission member 116 are made of thin members. Therefore, if the oscillator holding member 112 is not provided with the projecting portion 112a extending in the vertical direction, it is difficult to secure a sufficient amount of the positioning portion 116a, and the positioning portion 116a of the transmission member 116 is the oscillator holding member 112. There is a risk of riding on. When the positioning portion 116a rides on, the cushioning member 117 is biased and crushed, resulting in drive unevenness as shown in FIG. 3A.

As described above, in the vibration type motor 1 of the present embodiment, by providing the vibrator holding member 112 with a protruding portion 112a extending in the vertical direction, it is possible to obtain a driving characteristic in which driving unevenness is suppressed. Further, since the notch portion 115a is provided in the first transmission member 115 and the protruding portion 112a is arranged in the portion notched by the notch portion 115, it is possible to suppress the increase in size in the vertical direction.

For example, when the notch portion 115a is not provided in the first transmission member 115, the first transmission member 115 is arranged so as to be displaced upward in FIG. 4 (c) in order to avoid the protrusion 112a in FIG. 4 (c). It is necessary to do so, and the thickness L2 of the movable portion becomes thick.

Further, the first transmission member 115 is a member that transmits the force generated by the pressurizing member 114 to the pressurizing center P1, and component rigidity in the path from each pressurizing member 114 to the pressurizing center P1 is required. Depending on the arrangement of the notch 115a, the component rigidity of the path from the pressurizing member 114 to the pressurizing center P1 may decrease, so it may be necessary to increase the thickness of the transmission member 115 in order to prevent the decrease in rigidity. There is. However, in the vibration type motor 1 of the present embodiment, since the notch portion 115a is provided at a position deviated from the pressurizing center P1 in the moving direction of the vibrator 111, the path from the pressurizing member 114 to the pressurizing center P1. It is easy to secure the rigidity of parts. As a result, it is not necessary to increase the thickness of the transmission member 115, and it is possible to suppress the increase in size in the vertical direction.

Further, in the vibration type motor 1 of the present embodiment, as shown in FIG. 4A, the groove portion 112b, which is a positioning portion for positioning the first transmission member 115 on the vibrator holding member 112, is the moving direction of the vibrator 111. It is provided near the center in. The first transmission member 115 is provided with a convex portion that engages with the groove portion 112b, and the position of the first transmission member 115 with respect to the vibrator holding member 112 in the moving direction of the vibrator 111 is determined.

In the pressurizing mechanism of the vibration type motor 1, in order to make the surface pressure of the protrusion 111c of the vibrator 111 uniform, it is desired that the center of the pressurizing P1 and the center of the vibrator 111 exactly coincide with each other. Since the pressurizing center P1 is located at the position of the spherical protrusion 115b of the transmission member 115, the oscillator 111 and the transmission member 115 need to be positioned relatively accurately. Therefore, it is preferable that the positioning of the oscillator holding member 112 and the transmission member 115 is performed near the center of the oscillator holding member 112 and the first transmission member 115. The shape of the positioning portion for positioning the vibrator holding member 112 and the first transmission member 115 is not limited to the above configuration.

Further, it is preferable that the first transmission member 115 freely rotates with respect to the vibrator holding member 112 so as not to transmit an unnecessary moment to the vibrator 111. Therefore, in the vibration type motor 1 of the present embodiment, the positioning portion for positioning the vibrator holding member 112 and the transmission member 115 is arranged separately from the protruding portion 112a, and the vibrator 111 is located more than the protruding portion 112a. It is located on the center side.

Further, in the vibration type motor 1 of the present embodiment, four tension springs are arranged around the movable frame 118 as the pressurizing member 114. Specifically, as shown in FIG. 4A, the pressure center P1 is arranged so as to be located at the intersection of the diagonal lines of the rectangle formed by the four tension springs in the plane orthogonal to the pressure direction D2. There is.

Due to such an arrangement, the notch portion 115a is not arranged on the line segment connecting the pressurizing member 114 and the pressurizing center P1, and the component rigidity in the path from each pressurizing member 114 to the pressurizing center P1 is cut. It is not easily affected by the notch 115a.

Next, an example of a drive device to which the vibration type motor 1 of the present embodiment is applied will be described with reference to FIG.

FIG. 5 is a diagram illustrating an example of application of the vibration type motor 1 to a lens driving device. 5 (a) is a cross-sectional view of the lens driving device of the vibrating motor 1, FIG. 5 (b) is a view of the connection mechanism between the vibrating motor 1 and the lens holding frame 214 from above, FIG. 5 (c). Is a view of the connection mechanism between the vibration type motor 1 and the lens holding frame 214 as viewed from below.

As shown in FIG. 5A, a lens barrel 21 is detachably attached to the camera body 22, and the camera body 22 is provided with an image sensor 22a. The mount 221 of the camera body 22 has a bayonet portion for attaching the lens barrel 21 to the camera body 22. The lens barrel 21 has a fixed barrel 211 and is in contact with the flange portion of the mount 221. The fixed cylinder 211 and the mount 221 are fixed to screws (not shown). Further, the front lens barrel 212 for holding the lens G1 and the rear lens barrel 213 for holding the lens G3 are fixed to the fixed cylinder 211. The lens barrel 21 further includes a lens holding frame 214 to hold the lens G2. The lens holding frame 214 is further held so as to be movable in a straight line by a guide bar 215 held by the front lens barrel 212 and the rear lens barrel 213. The vibration type motor 1 is fixed to the rear lens barrel 213 with screws or the like (not shown).

As shown in FIG. 5B, in the lens holding frame 214, a driving force transmitting member 216 that transmits the driving force of the vibration type motor 1 to the lens holding frame 214 is provided with light from the lens G2 with respect to the lens holding frame 214. It is held rotatably around the axis. The driving force transmission member 216 is provided with a V-groove portion 216a, and the protrusion 118a provided on the movable frame 118 of the vibration type motor 1 comes into contact with the V-groove portion 216a. By connecting the driving force transmission member 216 and the movable frame 118 by the V-groove portion 216a and the protrusion 118a, the lens holding frame 214 moves with the movement of the vibration type motor 1.

In the lens drive device 2 using the vibration type motor 1, the radial dimension L3 is affected by the thickness of the vibration type motor 1. Therefore, by using the thinned vibration type motor 1, the radial dimension L3 of the lens driving device 2 can be miniaturized. Further, by using the vibration type motor 1 in which the drive unevenness is suppressed for the lens drive, it is possible to realize a higher speed and higher precision lens drive.

As described above, the lens drive device has been described as an example of the drive device using the vibration type motor 1, but the driven body driven by the vibration type motor 1 is not limited to the lens holding frame. For example, it may be a drive device in which an image pickup device, a stage, or the like is a driven body driven by a vibration type motor 1.

Further, the connecting mechanism for connecting the vibration type motor 1 and the driven body is not limited to the above configuration, and for example, the direction in which the V-groove portion is formed and the protruding direction of the protrusion portion may be different from the above configuration. However, the members formed by the V-groove portion and the protrusion portion may be different from the above configurations.

Further, in the above embodiment, the positioning portion 116a is provided at the center of the transmission member 116 in the Y-axis direction (direction orthogonal to the pressurizing direction and the moving direction of the vibrator 111) in FIG. 4A. , May be provided at other positions. Further, the positioning portion 116a may be provided at a plurality of positions away from the center of the transmission member 116 in the Y-axis direction of FIG. 4A. In such a configuration, the cutout portion 115a and the protruding portion 112a may be appropriately provided according to the position and number of the positioning portions 116a. For example, a plurality of protrusions 112a corresponding to the number of positioning portions 116a may be arranged between the wide notches 115a, or a plurality of positioning portions 116a may be arranged between the wide notches 115a. A configuration in which a wide protrusion 112a that can be contacted is arranged may be used.

Further, in the above embodiment, the protruding portion 112a of the vibrator holding member 112 is arranged in the portion notched by the notch portion 115a of the first transmission member 115, but instead of the notch portion 115a. A hole may be provided. That is, a hole portion is provided at a position separated by a predetermined distance from the end of the first transmission member 115 in the moving direction of the vibrator 111, and a protruding portion having a shape arranged in the hole portion serves as a vibrating portion holding member. It may be a provided configuration.

1 Vibration type motor 2 Lens drive device 111 Oscillator 112 Oscillator holding member 113 Friction member 114 Pressurizing member 115 First transmission member 116 Second transmission member

Claims (8)

A vibration type motor having an oscillator and a friction member in contact with the oscillator, and vibrating the oscillator to relatively move the oscillator and the friction member.
A holding member that holds the oscillator and
A pressurizing member that produces a pressurizing force that pressurizes the vibrator against the friction member, and a pressurizing member.
The first transmission member that transmits the pressing force and
It has a second transmission member arranged between the oscillator and the first transmission member, and has.
The first transmission member is a moving direction in which the vibrator and the friction member move relative to a pressurizing center of a pressing force that presses the vibrator to be transmitted to the second transmission member to the friction member. A notch or hole is provided at the position shifted to
The holding member is provided with a portion notched by the notch or a protrusion arranged in the hole.
The second transmission member is a vibration type motor provided with a contact portion that comes into contact with the protrusion. The vibration type motor according to claim 1, wherein the protruding portion extends in a pressurizing direction in which the vibrator pressurizes the friction member. The vibration type according to claim 1 or 2, wherein the second transmission member is positioned with respect to the holding member in the moving direction by abutting the protruding portion and the contact portion. motor. The vibration type motor according to claim 3, wherein the first transmission member is positioned with respect to the holding member at a position closer to the pressurizing center than the contact portion in the moving direction. The vibration type motor according to any one of claims 1 to 4, wherein the contact portion is provided at the end of the second transmission member in the moving direction. The pressurizing member is arranged at a plurality of positions surrounding the holding member in a plane orthogonal to the pressurizing direction.
One of claims 1 to 5, wherein the notch or hole is not arranged on a line segment connecting the pressurizing member and the pressurizing center in a plane orthogonal to the pressurizing direction. The vibration type motor described in the section. The vibration type motor according to any one of claims 1 to 6, wherein the first transmission member can be tilted with respect to the holding member in the moving direction. The vibration type motor according to any one of claims 1 to 7.
The driven body driven by the vibration type motor and
A drive device characterized by having.

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