JP2019221072A - Vibration wave motor and drive unit with vibration wave motor - Google Patents

Abstract

To provide a miniaturized vibration wave motor.SOLUTION: A vibration wave motor 3 of the present invention comprises: a vibrator 104 consisting of a piezoelectric element 103 and a diaphragm 102; a friction member 101 contacting the vibrator 104 by friction; pressurization means 109 for pressurizing the vibrator 104 to the friction member 101 to be energized; and holding member 112 for holding the friction member 101, in which the vibrator 104 and the friction member 101 relatively move, the pressurization means 109 is constituted of a rotation member 111 having a rotating shaft 111a extending along a direction of relative movement and an elastic member 110 for energizing the rotation member 111 in a rotation direction, and the holding member 112 holds the friction member 101 near both ends in the direction of relative movement of the friction member 101.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibration wave motor and a driving device including the vibration wave motor.

  Conventionally, in an ultrasonic motor, a driving force is obtained by pressing a vibrator that periodically vibrates by application of a high-frequency voltage to a friction member and making contact therewith. In such an ultrasonic motor, a desired driving force is generated by pressing a pressure contact portion between the vibrator and the friction member at a predetermined value. In Patent Literature 1, a pressure member of the vibrator is arranged on the back surface where the vibrator contacts the friction member, and the vibrator is pressed against the friction member.

JP-A-2015-126692

  However, in Patent Literature 1, since the members are arranged to be stacked, it is difficult to reduce the size of the unit in the thickness direction.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a downsized vibration wave motor.

  In order to solve the above problems, a vibration wave motor according to the present invention includes a vibrator including a piezoelectric element and a vibrating plate, a friction member that comes into frictional contact with the vibrator, and pressing the vibrator against the friction member. And a holding member for holding the friction member. The vibrator and the friction member move relative to each other, and the pressing means extends along the direction of the relative movement. A rotating member having a rotating shaft and an elastic member for urging the rotating member in a rotating direction, wherein the holding member is located near both ends in the direction of the relative movement of the friction member. The friction member is held.

  According to the present invention, it is possible to provide a downsized vibration wave motor.

(A) It is a top view of the vibration wave motor 3 of this invention. (B), (C) It is sectional drawing. (A), (B) is a figure which shows the case where the movable part 117 of the vibration wave motor 3 of this invention is located in an end part. (C) It is a figure showing a comparative example. FIG. 3 is a cross-sectional view illustrating a driving device including the vibration wave motor 3 of the present invention.

(Example)
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the direction of relative movement between a later-described vibrator 104 and the friction member 101 is the X-axis direction, the pressing direction of the pressing unit 109 is the Z-axis direction, and the direction orthogonal to the X-axis direction and the Y-axis direction is Y. Defined as the axial direction. The vibration wave motor 3 (ultrasonic motor) in the present embodiment is configured by the following members.

  FIG. 1A is a plan view of the vibration wave motor 3 of the present invention. FIG. 1B is a cross-sectional view of the vibration wave motor 3 along a cross section line IB-IB of FIG. 1A, and FIG. 1C is a vibration wave motor 3 of a cross section line IC-IC of FIG. Are respectively shown in cross section.

  The vibrator 104 includes a vibrating plate 102 which is a vibrating body having elasticity and a piezoelectric element 103. The vibration plate 102 and the piezoelectric element 103 are fixed by a known adhesive or the like, and the piezoelectric element 103 excites vibration (ultrasonic vibration) having a frequency in an ultrasonic region by applying a voltage.

  The vibrator 104 is fixed to the vibrator holding member 105 with a known adhesive or the like. The vibrator holding member 105 is connected to the movable frame 107 via a thin plate 108. By being connected by the thin sheet metal 108, the vibrator holding member 105 and the movable frame 107 can be relatively moved in the Z-axis direction without a load while being connected without play in the Y-axis direction and the X-axis direction. The movable frame 107 is fixed to the movable rail member 115. As described above, the vibrator 104, the vibrator holding member 105, the movable frame 107, the thin plate 108, and the movable rail member 115 constitute the movable portion 117.

  An elastic member 110 composed of a tension spring or the like connects the rotating member 111 and the movable rail member 115 and applies a pressing force in the Z-axis direction for bringing the vibrator 104 into frictional contact with the friction member 101. The rotating member 111 has a rotating shaft 111a on one side (first side) in the Y-axis direction orthogonal to the direction of relative movement, and the other side (second side) facing the one side. The elastic member 110 is engaged on the side. The rotating shaft 111a extends along the direction of relative movement, and a rotating connecting portion 115a of the movable rail member 115 is engaged with the rotating shaft 111a, and the rotating member is rotated about the rotating shaft 111a. 111 is configured to be rotatable. That is, the rotation shaft 111a and the rotation connection portion 115a form a hinge structure. In the present invention, the hinge structure is shorter than the length of the rotation member 111 in the direction of relative movement. Also, in FIG. 1A, two elastic members 110 are provided, but only one of the rotation shaft 111a or the elastic member 110 is provided substantially at the center in the relative movement direction of the vibration wave motor 3. It may be arranged. The rotating member 111 further includes a spherical projection 111b constituting a pressure unit substantially at the center in the direction of relative movement, and comes into contact with the buffer member 106 via the spherical projection 111b to transmit a pressing force. I have. The buffering member 106 prevents direct contact between the pressing portion of the rotating member 111 and the piezoelectric element 103, and prevents the piezoelectric element 103 from being damaged. Pressing means 109 is constituted by the elastic member 110 and the rotating member 111.

  The vicinity of both ends of the friction member 101 is held by the connecting portion 112a of the holding member 112. The holding member 112 also holds a fixed-side rail member 113, and the holding member 112, the friction member 101, and the fixed-side rail member 113 form a fixed portion 116.

  The movable-side rail member 115 has two grooves (not shown) extending in the X-axis direction, which are movable-side guides, and the rolling balls 114 are arranged in the respective grooves. On the other hand, the fixed-side rail member 113 disposed opposite to the movable-side rail member 115 is also provided with two grooves (not shown) extending in the X-axis direction, which are fixed-side guide portions. The rolling ball 114 is sandwiched between the fixed-side guide portion of the fixed-side rail member 113 and the movable-side guide portion of the movable-side rail member 115. With this configuration, the movable portion 117 is guided straight in the X-axis direction. .

  The vibration plate 102 has a contact portion 102a, and the contact portion 102a is in contact with the friction member 101 in a state where the friction member 101 is pressed and urged by the pressing force of the elastic member 110. When a driving voltage is applied to the piezoelectric element 103, ultrasonic vibration is excited, and a resonance phenomenon occurs in the vibrator 104. At this time, two types of standing waves are generated in the vibrator 104, and substantially elliptical motion occurs in the contact portion 102a of the diaphragm 102. When the contact portion 102a of the diaphragm 102 and the friction member 101 are in a pressure contact state, the elliptical motion generated at the contact portion 102a is efficiently transmitted to the friction member 101. As a result, the movable part 117 moves in the X-axis direction with respect to the fixed part 116.

  FIG. 1B shows a thickness T1 of the friction member 101 in the pressing direction, a thickness T2 of the vibrator 104 in the pressing direction, and a thickness T3 of the elastic member 110 in the pressing direction. In the conventional configuration, since the members are arranged so as to be stacked, it is difficult to reduce the size of the entire apparatus in the pressing direction. In the present invention, the rotation member 111 is configured to be rotatable around the rotation connection portion 115a, and the rotation member 111 is urged by the elastic member 110 in the rotation direction. Therefore, the elastic member 110 can be arranged so as not to be stacked on the friction member 101 and the vibrator 104, and the unit can be reduced in the pressing direction. Here, the position of the thickness T3 in the pressing direction is arranged to overlap both the thickness T1 and the thickness T2. Such an arrangement may be used because the effects of the invention can be obtained.

  Further, as shown in FIGS. 1A and 1B, the rotating member 111 comes into contact with the cushioning member 106 at a spherical projection 111b substantially at the center of the projection surface of the vibrator 104 viewed from the pressing direction. Transmits pressure. With this configuration, even when the rotation angle of the rotation shaft 111a of the rotation member 111 and the rotation connection portion 115a of the movable rail member 115 is inclined from an angle orthogonal to the Z axis, the pressing force is always stable. The power is transmitted to the buffer member 106.

  FIGS. 2A and 2B show a state in which the vibration wave motor 3 of the present invention is located at the drive end in the direction of relative movement, and the movable part 117 is in the direction of relative movement with the fixed part 116. Is located at the drive end of the vibration wave motor 3 in the unit. Note that FIG. 2B illustrates a cross-sectional view taken along a cross-sectional line IIA-IIA in FIG. That is, the vibrator 104 is located at the end of the friction member 101 in the direction of relative movement. At this time, the connecting portion 112a between the elastic member 110 and the holding member 112 overlaps when viewed from the Y-axis direction orthogonal to the direction of relative movement between the vibrator 104 and the friction member 101. With this configuration, it is possible to reduce the size of the relative movement as well as the size of the pressing direction.

  Next, with reference to FIGS. 2B and 2C, the downsizing in the direction of the relative movement will be described more specifically. FIG. 2C shows a comparative example with respect to FIG. In FIG. 2B, the length in the direction of relative movement of the connecting portion 112a of the holding member 112 is the length L1, the size in the direction of relative movement of the movable portion 117 is the length L2, and the length of the relative movement of the vibration wave motor 3 is L2. The dimensions with the length in the direction as the length L3 are shown. In the configuration of the vibration wave motor 3 of the present invention, since the elastic member 110 and the connecting portion 112a overlap in the Y-axis direction, in the driving range R of the movable portion 117, the movable portion 117 is driven by the stroke S in the direction of relative movement. It is possible.

  On the other hand, in a comparative example that does not adopt the configuration of the present invention, as shown in FIG. 2C, the elastic member 110 and the connecting portion 112a do not overlap in the Y-axis direction, so that the elastic member 110 interferes with the connecting portion 112a. I have. Therefore, in order to secure the same drive range R and stroke S as in the present invention, it is necessary to consider the length L4 in the direction of relative movement of the two elastic members 110, and as a result, the length in the longitudinal direction of the device is required. The dimension becomes the length L3 ′, which is longer than the length L3 of the vibration wave motor 3.

  Comparing the present invention and a comparative example, when the stroke S in the direction of the relative movement is the same, the size of the direction of the relative movement can be reduced by adopting the configuration of the present invention. Alternatively, in both cases, when the dimension of the vibration wave motor 3 in the direction of relative movement is set to the length L3, the driveable stroke S can be lengthened by adopting the configuration of the present invention. With the above configuration, the thickness and length of the vibration wave motor 3 can be reduced, the device can be downsized, and stable pressurization can be realized.

(Application example)
FIG. 3 shows a configuration of an imaging device to which the present invention can be applied. Note that, in the present description, a case will be described in which a driving device including the vibration wave motor 3 is mounted on an imaging device, but the present invention is not limited thereto. Also, an imaging device in which an imaging lens unit 1 and a camera body 2 described later are integrated will be described, but the imaging lens unit 1 may be an interchangeable lens.

  In FIG. 3, an imaging device body is configured by an imaging lens unit 1 and a camera body 2. The optical lens 4 is connected to the movable part 117 of the vibration wave motor 3 inside the imaging lens unit 1, and the optical lens 4 moves the optical axis 6 ( (In the X-axis direction). The lens barrel including the optical lens 4 and the vibration wave motor 3 constitute a driving device of the present invention. In a driving device in which the optical lens 4 is a focusing lens, the focusing lens moves in a direction substantially parallel to the optical axis 6 at the time of imaging, and a subject image is formed at the position of the imaging device 5 to form a focused image. Can be generated. Although FIG. 3 illustrates an example in which the driven body driven by the vibration wave motor 3 is the optical lens 4, if the driving apparatus includes a driven body driven by the vibration wave motor 3, for example, The present invention is also applicable to a driving device in which the driving body is the image sensor 5 or a stage.

3 Vibration wave motor 4 Optical lens 101 Friction member 102 Vibration plate 103 Piezoelectric element 104 Vibrator 109 Pressurizing means 110 Elastic member 111 Rotating member 111a Rotating shaft (hinge structure)
111b Spherical projection 112 Holding member 112a Connection 115a Rotating connection (hinge structure)

Claims (11)

A vibrator composed of a piezoelectric element and a vibrating plate,
A friction member that makes frictional contact with the vibrator;
Pressing means for pressing the vibrator against the friction member;
Holding member for holding the friction member,
The vibrator and the friction member relatively move,
The pressurizing means includes a rotating member having a rotating shaft extending along the direction of the relative movement, and an elastic member for urging the rotating member in the rotating direction,
The vibration wave motor, wherein the holding member holds the friction member near both ends in the direction of the relative movement of the friction member.   The rotating member includes the rotating shaft on a first side surface in a direction orthogonal to the direction of the relative movement, and the elastic member is provided on a second side surface facing the first side surface, The vibration wave motor according to claim 1, wherein an elastic member biases the rotating member, and the vibrator is pressed by rotating the rotating member. The holding member includes a connecting portion for holding the friction member near the both ends of the friction member,
The elastic member and the connecting portion overlap at a position of a drive end of the relative movement of the vibrator and the friction member when viewed from a direction orthogonal to a direction of the relative movement. 3. The vibration wave motor according to 1 or 2.   4. The elastic member according to claim 1, wherein a position in a pressing direction of urging the vibrator against the friction member overlaps with the vibrator or the friction member. 5. The vibration wave motor according to the paragraph.   2. The rotating member transmits a pressing force to the vibrator through a spherical projection at substantially the center of a projection plane of the vibrator viewed from a pressing direction of the pressing unit. The vibration wave motor according to any one of claims 1 to 4.   The vibration wave motor according to any one of claims 1 to 5, wherein the rotation shaft forms a hinge structure, and the hinge structure is shorter than a length of the rotation member in the direction of the relative movement. .   The vibration wave motor according to any one of claims 1 to 6, wherein the elastic member is configured by a tension spring, and one of the tension springs is disposed in the direction of the relative movement.   The vibration wave motor according to any one of claims 1 to 6, wherein one of the rotation shaft and the elastic member is disposed only at a substantially center of the direction of the relative movement.   The vibration wave motor according to any one of claims 1 to 8, wherein the vibrator generates vibration having a frequency in an ultrasonic range, and the vibration wave motor is an ultrasonic motor.   The driving device including the vibration wave motor according to claim 1, further comprising a driven body driven by the vibration wave motor.   The driving device according to claim 10, wherein the driven body is an optical lens.

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