JP6708472B2 - Vibration wave motor and optical device equipped with the vibration wave motor - Google Patents

Description

The present invention relates to a drive device, and more particularly to a vibration wave motor.

2. Description of the Related Art Conventionally, a vibration wave motor has been widely used as a drive source for optical devices such as cameras and lenses by utilizing features such as high torque output, high positioning accuracy, and quietness. In recent years, in a multi-group zoom lens configuration, a vibration wave motor having a relatively simple structure and a small size has been desired, and it is required to reduce the size of the drive device and improve the drive efficiency.

For example, Patent Document 1 discloses a vibration type driving device that uses a holding member that holds a vibrator that includes a connecting portion that extends in the longitudinal direction from the vibrator (see FIGS. 1 and 2). In addition, Patent Document 2 discloses a technique for improving driving efficiency by dividing a holding member that holds a vibrator and a power take-out member. Specifically, an ultrasonic motor is disclosed in which a holding member that holds a vibrator and a holding member that holds a pressure mechanism including a power take-out portion are connected via a roller and a leaf spring ( See FIG. 2). With such a configuration, it is movable in the pressurizing direction and is connected in the relative moving direction without rattling, so that the driving efficiency is improved.

JP, 2011-254587, A JP, 2005-126692, A

However, although the driving efficiency is improved in the above-described conventional technique, since the connecting portion of the holding member that holds the vibrator is formed in the longitudinal direction of the vibrator, the size of the drive device in plan view becomes large. I will end up.

Then, the objective of this invention is providing the downsized vibration wave motor, without reducing driving efficiency.

To achieve the above object, the present invention includes a vibrator, a biasing member, and a holding member that holds the vibrator, and the vibration generated in the vibrator causes friction between the vibrator and the vibrator. A vibration wave motor in which a contacting friction member moves relatively, wherein the biasing member biases the vibrator in the direction of the friction member, and the vibrator moves in the biasing direction of the biasing member. The holding member includes an extending portion extending from the vibrator , the holding member includes a guide portion near a position facing the extending portion, and a rolling member is narrowed between the extending portion and the guide portion. Characterized by being carried.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the vibration wave motor which reduced the drive device, without reducing drive efficiency.

It is a disassembled perspective view of the vibration wave motor 3 of embodiment of this invention. It is a perspective view of the vibration wave motor 3 of embodiment of this invention. It is sectional drawing in the relative movement direction of the vibration wave motor 3 of embodiment of this invention. It is sectional drawing in the Y-axis direction of the vibration wave motor 3 of embodiment of this invention. (A), (B) It is a perspective view of diaphragm 102 of vibration wave motor 3 of an embodiment of the present invention. (A) It is a front view which shows the structure of the diaphragm 102 and the vibrator holding member 105 of the vibration wave motor 3 of embodiment of this invention. FIG. 7B is a bottom view showing the configurations of the diaphragm 102 and the vibrator holding member 105. FIG. 6C is a cross-sectional view in the Y-axis direction showing the configurations of the diaphragm 102 and the vibrator holding member 105. (A) It is a front view showing a mode of vibration of diaphragm 102 of vibration wave motor 3 of an embodiment of the present invention. FIG. 6B is a bottom view showing the mode of vibration of diaphragm 102. FIG. 6C is a cross-sectional view in the Y-axis direction showing a vibration mode of the diaphragm 102. (D) It is a partial enlarged view of the extension part 102e. (A) It is a bottom view showing the diaphragm 1102 in Example 1 of the present invention. FIG. 6B is a bottom view showing the diaphragm 2102 according to the second embodiment of the present invention. FIG. 6C is a bottom view showing the diaphragm 3102 according to the third embodiment of the present invention. It is sectional drawing of the imaging device which applied the vibration wave motor 3 of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the relative movement direction of the moving portion 100 of the vibration wave motor 3 is the X-axis direction, the direction in which the vibrator 101 receives the biasing force is the Z-axis direction, and the direction orthogonal to both the X-axis direction and the Z-axis direction is the Y-axis direction. It is defined as.

FIG. 1 shows an exploded perspective view of a vibration wave motor 3 (ultrasonic motor) according to the present invention. 2 is a perspective view of the vibration wave motor 3, FIG. 3 is a cross-sectional view of the vibration wave motor 3 in the X-axis direction which is a relative movement direction, and FIG. 4 is a cross-sectional view of the vibration wave motor 3 in the Y-axis direction. The vibration wave motor 3 in the present embodiment is configured by each member described below.

Referring to FIG. 1, the moving unit 100 of the vibration wave motor 3 includes a vibrator 101, a vibrator holding member 105, an elastic member 106, a spring guide 107, a spring 108 (biasing member), a biasing mechanism holding member 109, and the like. Has been done. The stationary portion that does not move is composed of the friction member 111, the base 112, the cover plate 113, and the like. The vibration wave motor 3 shown in FIG. 1 includes a friction member 111 as a stationary portion that does not move, but the vibrator 101 is used as a member other than the vibration wave motor 3 (for example, a part of the lens holding member 4 in FIG. 9). They may be brought into frictional contact, and the vibration wave motor 3 may not include the friction member 111.

The vibrator 101 is composed of a diaphragm 102 as an elastic body and a piezoelectric element 103. The vibrating plate 102 and the piezoelectric element 103 are fixed by a known adhesive material or the like, and the piezoelectric element 103 excites vibration of a frequency in the ultrasonic range by applying a voltage. The diaphragm 102 includes a protrusion 102a (see FIG. 5), and the protrusion 102a is in contact with the friction member 111 while being biased by a biasing force of a spring 108 described later. When the vibration plate 102 and the piezoelectric element 103 are bonded to each other, the resonance phenomenon occurs in the vibrator 101 by exciting the piezoelectric element 103 with a vibration having a frequency in an ultrasonic region, for example. At this time, two types of standing waves are generated in the oscillator 101, so that a substantially elliptical motion is generated at the tip of the protrusion 102 a of the diaphragm 102.

The vibrator 101 further includes an extending portion 102e as a connecting portion with a vibrator holding member 105 described later. A spherical rolling member 104 is sandwiched between the extending portion 102e and the vibrator holding member 105. The vibrator holding member 105 and the biasing mechanism holding member 109 are fixed by a known technique such as bonding.

The urging mechanism holding member 109 has a holding hole for receiving the elastic member 106 and the spring guide 107. By sandwiching the spring 108 between the biasing mechanism holding member 109 and the spring guide 107, the spring 108 generates a biasing force in the biasing direction 122 indicated by the arrow.

The elastic member 106 is arranged between the piezoelectric element 103 and the spring guide 107. The elastic member 106 prevents the piezoelectric element 103 from being damaged by preventing direct contact between the spring guide 107 and the piezoelectric element 103.

The biasing mechanism holding member 109 includes three moving side guide portions. On the other hand, the cover plate 113 as the fixed portion also includes a fixed side guide portion having a predetermined length in the X-axis direction. The three spherical rolling members 110 are sandwiched by the moving side guide portion of the biasing mechanism holding member 109 and the fixed side guide portion of the cover plate 113. It should be noted that although the movable guide portion and the fixed guide portion described above have a movable range limiting portion for limiting the movable range of the rolling member 110, the description thereof will be omitted in the description of the present embodiment.

The vibration wave motor 3 further includes a base 112. The base 112 and the cover plate 113 are fixed in the Z-axis direction by screws (not shown) or the like. Further, on the bottom surface side of the base 112, the friction member 111 is fixed with screws or the like (not shown).

Next, the biasing force generated in the spring 108 will be described. The biasing force of the spring 108 is transmitted to the vibrator 101 via the elastic member 106. Then, the protrusion 102a included in the diaphragm 102 makes frictional contact with the friction member 111 while being pressed by the transmitted biasing force (pressurized contact state). Here, the biasing direction 122 of the spring 108 is substantially perpendicular to the friction member 111 and substantially coincides with the Z-axis direction. On the other hand, the pressure reaction force from the friction member 111 is received by the cover plate 113 via the moving portion 100 and the three rolling members 110.

When a drive voltage is applied to the piezoelectric element 103 in this pressure contact state, the elliptical motion generated in the vibrator 101 is efficiently transmitted to the friction member 111. As a result, the moving unit 100 can move back and forth in the relative movement direction 121 indicated by the arrow. The power take-out portion 109p (see FIG. 4) included in the urging mechanism holding member 109 is connected to the lens holding member 4 (see FIG. 9) via a connecting member (not shown). It becomes possible to move to a position.

Next, the configuration of the diaphragm 102 of the vibration wave motor 3 of the present invention will be described. 5A and 5B show perspective views of the diaphragm 102 of the vibration wave motor 3 of the present invention. The diaphragm 102 has a flat plate portion 102b, and the flat plate portion 102b is formed with a protrusion 102a and a plurality of extending portions 102e. The protrusion 102a protrudes from the flat plate 102b, and the height of the protrusion is set to a desired height required to amplify the amplitude of the above-described substantially elliptical motion. The extending portion 102e is formed to extend in the X-axis direction, and is bent in the −Z-axis direction at the bent portion 102f (root portion) to extend in the urging direction 122. There is. The long side of the bent extending portion 102e extends in the X-axis direction.

A standing wall portion 102w for receiving a rolling member 104, which will be described later, is formed at the end portion on the opposite side in the long side direction of the extending portion 102e provided with the bent portion 102f, while changing its direction in the Y-axis direction. There is. In the embodiment shown in FIG. 5B, a pair of the plurality of extending portions 102e is arranged so as to face each other, and the respective standing wall portions 102w face each other and are configured to be separated from each other. There is. Since the standing wall portion 102w has a shape that is separated in the Y-axis direction, the standing wall portion 102w can receive the rolling member 104 and connect the diaphragm 102 and the vibrator holding member 105. Is possible. A rolling surface 102r is formed on the side of the standing wall portion 102w that receives the rolling member 104.

In the embodiment shown in FIG. 5A, the extending portions 102e are arranged so as to face each other in the X-axis direction, and a gap 102s is provided in a portion where the extending portions 102e are adjacent to each other. However, the notch may be provided instead of the gap 102s.

In the related art, as shown in FIG. 2 of Patent Document 1, for example, the diaphragm includes a connecting portion extending from the flat plate portion in the X-axis direction. The length in the X-axis direction is the sum of the length of the flat plate portion and the length of the connecting portion, and the connecting portion of the diaphragm extending in the X-axis direction is a factor that hinders downsizing of the device. Was there.

Therefore, in the present invention, as shown in FIGS. 5(A) and 5(B), the diaphragm 102 forms an extending portion 102e as a connecting portion in the urging direction 122, and the extending portion 102e extends in the X-axis direction of the prior art. The space required for constructing the extended connecting portion is unnecessary. With such a configuration, the device can be downsized.

Next, a method of connecting the vibrator 101 and the vibrator holding member 105 will be described. 6A is a front view of the vibration wave motor 3 in which the diaphragm 102 and the vibrator holding member 105 are connected, FIG. 6B is a bottom view, and FIG. 6C is a cross-sectional line VIC- in FIG. 6B. The cross-sectional view in VIC is shown. The vibrating plate 102 has a substantially rectangular shape, and is substantially fitted to the vibrator holding member 105 from the Z-axis direction. The vibrator holding member 105 has a guide portion near a position facing the extending portion 102e. 105c is provided. The rolling member 104 is sandwiched between the standing wall portion 102w of the extending portion 102e and the guide portion 105c, so that the vibrator 101 and the vibrator holding member 105 are connected to each other. In the present embodiment, the rolling member 104 is sandwiched between the standing wall portion 102w and the guide portion 105c of the vibrator holding member 105. However, if the rolling member 104 is sandwiched, the means will be provided. Does not matter.

A plurality of rolling members 104 are provided and are arranged along the Y-axis direction that is orthogonal to the direction of relative movement. With the above configuration, the vibrator 101 is movable in the biasing direction 122 of the spring 108 with respect to the vibrator holding member 105 due to the rolling of the rolling member 104, and there is play in the relative movement direction 121. It is connected to the vibrator holding member 105 in the absence. As a result, it becomes possible to hold the vibrator 101 without lowering the driving efficiency.

Further, in this embodiment, the protrusion 102a is formed between the flat plate 102b and the friction member 111, and the extension 102e, the vibrator holding member 105, and the guide 105c are flat in the biasing direction 122. It is located between the portion 102b and the friction member 111. That is, in constructing the vibrator holding member 105, by effectively utilizing the space excluding the protrusion 102a, interference with the piezoelectric element 103 and the elastic member 106 in the unit of the vibration wave motor 3 is eliminated. Therefore, further miniaturization becomes possible in each of the Z-axis direction which is the thickness direction of the unit of the vibration wave motor 3, the X-axis direction which is the longitudinal direction, and the Y-axis direction which is the lateral direction.

In the present embodiment, the extending portion 102e is provided on the vibrating plate 102 that constitutes the vibrator 101. However, another component that extends in the relative movement direction 121 is fixed to the piezoelectric element 103 or the vibrating plate 102. It may be equipped with.

Next, a vibration mode of the diaphragm 102 having the extending portion 102e will be described with reference to FIGS. 7A is a front view of the diaphragm 102, FIG. 7B is a bottom view of the diaphragm 102, FIG. 7C is a cross-sectional view of the diaphragm 102 in the X-axis direction, and FIG. 7D is an enlarged view of the extending portion 102e. The figure is shown. Note that FIG. 7D shows the displacement of the extending portion 102e in the Z-axis direction due to bending vibration, which will be described later, in an enlarged manner to simplify the description.

When the vibrator 101 is excited with vibrations having a frequency in the ultrasonic range, two types of standing waves of vibrations are generated. A curve 133 and a curve 134, which are shown by alternate long and short dash lines, imitate one state of those vibrations respectively represent the primary bending vibration and the secondary bending vibration. The dotted line 135 represents the neutral plane of those vibrations, and the dotted line 136 and the straight line 137 represent the nodes and antinodes of the respective vibrations.

As shown in FIG. 7A, the bent portion 102f (root portion) of the extending portion 102e is provided at the position of the antinode 137 of the secondary bending vibration excited by the vibrator 101 in the X-axis direction. ing. The extending portion 102e extends from the diaphragm 102 in the urging direction 122 to form a pair of adjacent standing wall portions 102w, and a gap 102s (notch) is provided between the standing wall portions 102w. There is. If the extending portion 102e does not have the gap 102s, the extending portion 102e may be distorted in the X-axis direction due to vibration, which may hinder ultrasonic vibration. Therefore, by providing the gap 102s in this manner, it is possible to reduce the inhibition of ultrasonic vibration due to the distortion of the extending portion 102e.

As described above, the bent portion 102f of the extending portion 102e is provided at the position of the antinode 137 of the secondary bending vibration excited by the vibrator 101. Therefore, the bent portion 102f only displaces in the Z-axis direction according to the secondary bending vibration indicated by the curve 134. As a result, as shown in FIG. 7D, the standing wall portion 102w of the extending portion 102e is displaced in the Z-axis direction, but the strain in the X-axis direction is hardly generated, so that the rolling member 104 rolls. Is hard to be hindered. As a result, the driving force by ultrasonic vibration can be efficiently obtained.

(Example 1)
FIG. 8A is a first embodiment of the present invention and shows a bottom view of a state in which the diaphragm 1102 and the vibrator holding member 1105 are connected. In the first embodiment, the extending portion 1102e has elasticity, and the rolling member 104 is urged toward the guide portion 1105c of the vibrator holding member 1105 by the urging force f due to this elasticity, and at the same time, the extending portion 1102e. And the guide portion 1105c. In particular, the extending portion 1102e has a notch or gap 1102s, and the rolling member 104 is biased by elastically deforming the notch or gap 1102s. The extending portion 1102e extends in the urging direction 122 so as to wrap the vibrator holding member 1105 from the outside.

(Example 2)
FIG. 8B is a second embodiment of the present invention and shows a bottom view of a state in which the diaphragm 2102 and the vibrator holding member 2105 are connected. In the second embodiment, the member of the vibrator holding member 2105 extending in the X-axis direction is biased in the Y-axis direction by the spring force F of the compression spring SP, and the biasing force f by this spring force F causes the rolling member 104 to move. I am urged. The extending portion 2102e extends in the urging direction 122 so as to wrap the vibrator holding member 2105 from the outside, as in the first embodiment.

(Example 3)
FIG. 8C is a bottom view of the third embodiment of the present invention in a state where the vibration plate 3102 and the vibrator holding member 3105 are connected. In the first embodiment described above, the extension 1102e extends from the outside of the vibrator holding member 1105. However, in the third embodiment, the vibrating plate 3102 is connected so as to enter the inside of the frame-shaped vibrator holding member 3105, and the extending portion 3102e extends in the urging direction 122 inside the vibrator holding member 3105. .. The rolling member 104 is urged by the elastic urging force f of the extending portion 3102e or by the urging force f of the resin spring of the vibrator holding member 3105 made of a resin material. May be.

(Application example)
FIG. 9 shows the configuration of an imaging device as an optical device to which the vibration wave motor 3 according to the present invention can be applied. A case where the vibration wave motor 3 is mounted on the image pickup apparatus will be described, but this does not limit the present invention. Further, although an image pickup apparatus in which an image pickup lens unit 1 and a camera body 2 described later are integrated will be described, the image pickup lens unit 1 may be a replaceable lens barrel as an optical device.

In FIG. 9, the imaging lens unit 1 and the camera body 2 form a main body of the imaging device. Inside the imaging lens unit 1, the lens holding member 4 that holds the focus lens is connected to the vibration wave motor 3, and the vibrator 101 that constitutes the vibration wave motor 3 moves to cause the lens holding member 4 to emit light. It is movable in a direction substantially parallel to the axis 6. At the time of image pickup, the lens holding member 4 moves in a direction substantially parallel to the optical axis 6, and the subject image is formed at the position of the image pickup element 5, so that a focused image can be generated. The lens holding member 4 moved by the vibration wave motor 3 may hold a zoom lens instead of the focus lens. Further, the lens holding member 4 may hold the correction lens used for image blur correction by making the moving direction of the lens holding member 4 by the vibration wave motor 3 substantially orthogonal to the optical axis 6.

As described above, according to the present invention, it is possible to provide the vibration wave motor 3 capable of maintaining the driving efficiency and being downsized. Although the preferred embodiments and examples of the present invention have been described, the present invention is not limited to these and various modifications and changes can be made within the scope of the invention. For example, in the above-described embodiments and examples, the configuration in which the vibrator 101 of the vibration wave motor 3 moves and the friction member 111 does not move is described, but the vibrator 101 may not move but the friction member 111 may move. .. In this configuration, the power take-out portion may be provided in the friction member 111 or a member that moves together with the friction member 111.

1 Photographic lens unit (imaging device)
3 Vibration Wave Motor 101 Vibrator 102 Vibrating Plate 102a Protrusion 102b Flat Plate 102e Extending Part 103 Piezoelectric Element 104 Rolling Member 105 Transducer Holding Member (Holding Member)
105c Guide part 108 Spring (biasing member)
111 Friction member 137 Vibration antinode

Claims (12)

Oscillator
A biasing member,
A holding member for holding the vibrator,
A vibration wave motor in which the vibrator and a friction member that makes frictional contact with the vibrator move relative to each other by vibration generated in the vibrator,
The biasing member biases the vibrator in the direction of the friction member,
The vibrator includes an extension portion extending from the vibrator in a biasing direction of the biasing member,
The holding member includes a guide portion in the vicinity of a position facing the extension portion,
A vibration wave motor, wherein a rolling member is sandwiched between the extending portion and the guide portion. The vibration wave motor according to claim 1, wherein the extending portion has a notch or a gap, and the rolling member is biased by elastically deforming the notch or the gap. .. The vibration wave motor according to claim 1, wherein the extending portion has a shape of two opposing standing walls. The vibration wave motor according to any one of claims 1 to 3, wherein a plurality of the rolling members are provided and sandwiched along a direction orthogonal to the direction of the relative movement. The vibration wave motor according to claim 1, wherein the vibrator includes a piezoelectric element and a vibration plate. The vibration wave motor according to claim 5, wherein the vibrating plate of the vibrator has the extending portion extending in the biasing direction. The vibrating plate includes a flat plate portion and a projection portion that projects from the flat plate portion and makes frictional contact with the friction member, and the extending portion is provided between the flat plate portion and the friction member in the biasing direction. The vibration wave motor according to claim 5 or 6, characterized in that. The vibrating plate includes a flat plate portion and a projection portion that projects from the flat plate portion and makes frictional contact with the friction member, and the extension portion is provided on a side where the projection portion is provided in the biasing direction. The vibration wave motor according to any one of claims 5 to 7. 9. The vibration wave motor according to claim 5, wherein the vibration plate having a substantially rectangular shape is substantially fitted to the holding member. The vibration wave motor according to any one of claims 1 to 9, wherein the extending portion extends from a vicinity of an antinode of vibration of the vibrator. The vibration wave motor according to any one of claims 1 to 9, wherein the vibration wave motor is an ultrasonic wave motor in which the vibration has a frequency in an ultrasonic wave region. An optical device equipped with the vibration wave motor according to claim 1.

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