JP2019083664A - Vibration wave motor, lens device, and imaging apparatus - Google Patents

Abstract

To provide a compact vibration wave motor.SOLUTION: A vibration wave motor (1) includes: a vibrator (100) including a piezoelectric element (103) and a vibrator (101); a friction member (104) in frictional contact with the vibrator; a pressure member (111) for pressing the vibrator to the friction member; and guide means (118) for linearly guiding a relative movement between the vibrator and the friction member. The vibrator and the friction member move relative to each other by vibration generated in the vibrator. The guide means has a pressure holding portion (112a) for holding the pressure member.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vibration wave motor applicable to a lens device or the like.

  Patent Document 1 discloses an ultrasonic motor that relatively drives a sliding member by pressing a vibrator that periodically vibrates by application of a high frequency voltage to the sliding member.

JP, 2015-126692, A

  The ultrasonic motor disclosed in Patent Document 1 includes a vibrator, a friction member, pressing means for pressing the vibrator against the friction member, and a guide member for guiding the drive of the vibrator.

  However, since the pressing means disclosed in Patent Document 1 is disposed so as to be stacked in the pressing direction of the vibrator, the size in the thickness direction of the ultrasonic motor is increased. In addition, since the guide portion is disposed at a position different from the pressurizing means, the size of the ultrasonic motor is increased. As a result, it is difficult to miniaturize the ultrasonic motor.

  Then, this invention aims at providing a small vibration wave motor, a lens apparatus, and an imaging device.

  An oscillatory wave motor according to one aspect of the present invention comprises a vibrator including a piezoelectric element and a vibrator, a friction member in frictional contact with the vibrator, and a pressure member for pressing the vibrator against the friction member. A guide means for linearly guiding relative movement between the vibrator and the friction member, wherein the vibrator and the friction member move relative to each other by vibration generated in the vibrator, and the guide means And a pressure holding unit for holding the pressure member.

  A lens apparatus as another aspect of the present invention includes the vibration wave motor and an optical system driven by the vibration wave motor.

  An imaging device as another aspect of the present invention includes the lens device and an imaging element that photoelectrically converts an optical image formed through the lens device.

  Other objects and features of the present invention will be described in the following embodiments.

  According to the present invention, it is possible to provide a compact vibration wave motor, a lens device, and an imaging device.

It is a perspective view of a vibration wave motor in this embodiment. It is an exploded perspective view of a vibration wave motor in this embodiment. It is a side sectional view of a vibration wave motor in this embodiment. It is front sectional drawing of the vibration wave motor in this embodiment. It is a principal part perspective view of a vibration wave motor in this embodiment. It is principal part sectional drawing which shows the positional relationship of the vibration wave motor in this embodiment. It is principal part sectional drawing of the imaging device in this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the vibration wave motor 1 in the present embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a perspective view of a vibration wave motor 1. FIG. 2 is an exploded perspective view of the vibration wave motor 1. FIG. 3 is a side sectional view of the vibration wave motor 1. FIG. 4 is a front sectional view of the vibration wave motor 1. FIG. 5 is a perspective view of an essential part of the vibration wave motor 1.

  A vibrator 101 is fixed to the vibrator holding member 102 by welding, a known adhesive, or the like. The piezoelectric element 103 is fixed to the vibrating body 101 by a known adhesive or the like. The vibrator 100 is constituted by the vibrator 101 and the piezoelectric element 103. When a high frequency voltage is applied to the piezoelectric element 103, the vibrating body 101 causes resonance. The vibrator 100 is configured to generate ultrasonic vibration when a high frequency drive voltage is applied. As a result, the tip of the pressure contact portion 100 a formed in the vibrator 100 causes elliptical vibration.

  By changing the frequency or the phase of the high frequency voltage applied to the piezoelectric element 103, it is possible to appropriately change the rotation direction and the elliptic ratio to generate a desired movement. For this reason, the driving force for relatively moving is generated by bringing the vibrator 100 into pressure contact with the frictional contact surface 104 a of the friction member 104 which is the other part, and the vibrator 100 is frictionally moved against the vibrator 100 with respect to the friction member 104. It is possible to advance and retract in the relative movement direction (X-axis direction) with the member 104. Thus, the vibrator 100 and the friction member 104 move relative to each other by the ultrasonic vibration generated in the vibrator 100.

  In the holding case 105 for holding the vibrator holding member 102 and the pressure holding member 110 described later, a connecting means 116 including a roller 106 b and a plate spring 107 is incorporated. The plate spring 107, which is an urging member having a predetermined elasticity, abuts on the holding case 105. The roller 106 b is sandwiched between the plate spring 107 and the vibrator holding member 102 and is movable in the pressure direction (Z-axis direction). In the present embodiment, the connection means 116 includes the roller 106 b and the leaf spring 107, but the roller 106 b is not limited to this as long as it can freely move in the Z-axis direction. The plate spring 107 is not limited to this as long as it has a biasing function.

  The vibrator holding member 102 is urged in the relative movement direction (X-axis direction) between the vibrator 100 and the friction member 104 through the roller 106b by the urging force of the plate spring 107, and the holding housing 105 is in the X-axis direction. It is urged to. The biasing force at this time is generated in a direction (X-axis direction) orthogonal to the pressing direction (Z-axis direction) of the vibrator 100. As a result, the roller 106 a incorporated in the other is also held between the holding housing 105 and the vibrator holding member 102.

  With the above configuration, no rattling occurs in the relative movement direction (X-axis direction) between the vibrator 100 and the friction member 104, and the rollers 106a and 106b slide in the pressure direction (Z-axis direction). It is possible to realize the connection means 116 in which the dynamic resistance does not substantially occur. At this time, the biasing force of the plate spring 107 is set to be larger than the inertial force due to acceleration / deceleration that occurs at the start and stop of operation of the holding housing 105 and the driven unit. By this setting, relative displacement in the relative movement direction (X-axis direction) between the vibrator 100 and the friction member 104 due to the inertial force at the time of driving occurs between the vibrator holding member 102 and the vibrator 100 and the holding housing 105. Therefore, stable drive control can be realized.

  Reference numeral 110 denotes a pressure holding member, and reference numeral 111 denotes a plurality of pressure springs (pressure members) for pressing the vibrator 100 against the friction member 104. The pressure holding member 110 and the pressure member 111 constitute a pressure means 117. Reference numeral 118 denotes guide means for guiding the relative movement between the vibrator 100 and the friction member 104 in a straight line. The guide means 118 includes rolling members 114 a, 114 b, 114 c, a first guide member 113, and a second guide member 112. The first guide member 113 is a fixing member which holds and fixes the rolling members 114 a to 114 c in a rollable manner. The second guide member 112 is a movable member which holds the rolling members 114 a to 114 c so as to be able to roll and move. The second guide member 112 is connected to the vibrator 100 via the vibrator holding member 102, the connection unit 116, and the holding housing 105. The second guide member 112 moves substantially integrally with the vibrator 100 in the relative movement direction of the vibrator 100 and the friction member 104. The second guide member 112 is also a member for transmitting the driving force generated by the vibrator 100 to the outside.

  The pressure holding member 110 has a connecting portion for connecting and holding the pressure member 111. The second guide member 112 is provided with a pressure holding unit 112 a that connects and holds the pressure member 111. The pressing member 111 includes a first hook portion 111 c as a connecting portion connected and held by the second guide member 112, and a second hook portion 111 d as a connecting portion connected and held by the pressure holding member 110. Have. The pressure member 111 is disposed between the connecting portion provided on the pressure holding member 110 and the pressure holding portion 112 a of the second guide member 112. As a result, a tensile spring force is generated between the pressure holding member 110 and the second guide member 112, and the pressure holding member 110 is pulled in the Z-axis direction by the spring force generated by the pressure member 111. Similarly, the second guide member 112 is drawn in the Z-axis direction by the spring force generated by the pressure member 111.

  In the present embodiment, when viewed from the direction (X-axis direction) orthogonal to the pressure direction (Z-axis direction) of the pressure member 111, the first guide member 113 overlaps with at least a part of the pressure member 111. There is. That is, the end of the connecting portion 111 c side of the pressing member 111 with the second guide member 112 (the connecting side with the second guide member 112) is connected with the first end portion 111 a and the pressure holding member 110. The end of the portion 111 d side (the side connected to the pressure holding member 110) is referred to as a second end 111 b. At this time, the first guide member 113 is disposed between the first end 111a and the second end 111b (within the range of the distance 111h) in the pressing direction (Z-axis direction).

  The pressure holding member 110 is provided with a pressure portion 110 a formed by a substantially hemispherical protrusion, and the pressure portion 110 a abuts on the elastic member 109. The pressure holding member 110 is configured to press and hold the piezoelectric element 103 with the elastic member 109 interposed therebetween, and a spring force generated in the pressure member 111 is a pressure direction of the vibrator 100 via these members ( Work in the Z axis direction). As a result, the pressure contact portion 100 a of the vibrator 100 and the frictional contact surface 104 a of the frictional member 104 can be brought into frictional contact with each other. The elastic member 109 prevents direct contact between the pressure portion 110 a of the pressure holding member 110 and the piezoelectric element 103, and prevents damage to the piezoelectric element 103.

  The second guide member 112 is fixed to the holding case 105 by a known technique such as adhesion or screwing. The second guide member 112 holds the rolling member 114 for guiding the holding housing 105 in the relative movement direction (X-axis direction) of the vibrator 100 and the friction member 104 which are the optical axis direction. A portion 112b. The rolling holding portion 112 b is disposed on the side opposite to the pressing holding portion 112 a that holds the pressing member 111 in connection. That is, the pressure holding portion 112a which is the above-described pressure holding function and the rolling holding portion 112b which is the rolling holding function are disposed integrally on the front and back. As a result, since pressure holding and rolling holding can be performed substantially the same, space saving is realized, and downsizing of the vibration wave motor 1 becomes possible.

  The first guide member 113 is provided with an opening (a relief) 113 a into which the friction member 104 is inserted. Thereby, interference of the first guide member 113 with the friction member 104 can be avoided. The friction member 104 and the first guide member 113 are fixed to the ground plate 115 by a known technique such as screwing. The first guide member 113 is provided with a V-shaped groove or a flat surface on the surface facing the second guide member 112. The first guide member 113 rectilinearly guides the rolling members 114 a to 114 c by holding the rolling members 114 a to 114 c between the first guide member 113 and the second guide member 112 and rolling them. Thus, the holding housing 105 can be supported so as to be able to advance and retract along the relative movement direction (X-axis direction) of the vibrator 100 and the friction member 104 which are the optical axis direction. That is, as shown in FIG. 5, by holding the rolling members 114b (114a, 114c) between the first guide member 112 and the second guide member 113, which are opposed to each other, the vibrator 100 causes friction. When moving relative to the member 104, it is guided so as to be able to drive straight.

  Next, with reference to FIG. 6, the positional relationship of the vibration wave motor 1 will be described. FIG. 6 is a cross-sectional view of the main part showing the positional relationship of the vibration wave motor 1. 6A to 6C, when the moving member including the second guide member 112 is driven (moves) rectilinearly in the X-axis direction, the end, the center, and the end on the opposite side The positional relationship of the moving member located in the part is shown.

  In the state of FIG. 6A, the rolling member 114c is disposed at a position farther than the first hook portion 111c of the pressing member 111 in the X-axis direction with the vibrator 100 as a reference. When the vibrator 100 and the friction member 104 move relative to each other, the second guide member 112 moves substantially integrally with the vibrator 100. At this time, the rolling member 114c moves in the X axis direction while rolling. FIG. 6 (b) shows the positional relationship in the state after the rolling member 114c has moved. Since the second guide member 112 and the rolling member 114c have different amounts of movement in the X-axis direction, the positional relationship between the pressure holding portion 112a holding the pressing member 111 and the rolling member 114c changes. The rolling member 114 c is disposed at a position closer to the first hook portion 111 c of the pressing member 111 in the X-axis direction with reference to the vibrator 100. That is, the rolling member 114 c passes through the inside of the first hook portion 111 c of the pressing member 111.

  Next, focusing on the rolling member 114b, in the state of FIG. 6B, the rolling member 114b is closer to the first hook portion 111c of the pressing member 111 in the X-axis direction based on the vibrator 100. It is placed in position. When the vibrator 100 and the friction member 104 move relative to each other from the state shown in FIG. 6B, the second guide member 112 moves substantially integrally with the vibrator 100. The rolling member 114 b moves in the X axis direction while rolling. FIG. 6C shows the positional relationship in the state after the rolling member 114b has moved. The amounts of movement of the second guide member 112 and the rolling member 114 b differ from each other in the X-axis direction. For this reason, the rolling member 114b is disposed at a position farther than the first hook portion 111c of the pressing member 111 in the X-axis direction with reference to the vibrator 100. That is, the rolling member 114 b passes through the inside of the first hook portion 111 c of the pressing member 111.

  As described above, the rolling members 114 a to 114 c are disposed so as to pass through the inside of the first hook portion 111 c when the vibrator 100 and the friction member 104 move relative to each other. Therefore, the diameter of the first hook portion 111c needs to be set larger than the diameter of the rolling members (rolling balls) 114a to 114c. Here, if the size of the pressing member 111 is set to match the entire size based on the first hook portion 111c, the pressing member 111 becomes large, and the size of the vibration wave motor 1 becomes large. In order to avoid this, as shown in FIG. 4, the coil portion 111 e of the pressure member 111 is configured to gradually increase in diameter toward the first hook portion 111 c. As a result, it is possible to avoid enlargement of the vibration wave motor 1 while sufficiently securing the diameter of the first hook portion 111c through which the rolling members 114a to 114c pass.

  As described above, the guide unit 118 includes the pressure holding unit 112 a that holds the pressure member 111. That is, the guide means 118 has both a mechanism for linearly guiding relative movement between the vibrator 100 and the friction member 104 and a mechanism for holding the pressure member 111 for pressing the vibrator 100 against the friction member 104. Therefore, the vibration wave motor 1 can be miniaturized as compared with the configuration in which the straight advance guide mechanism and the holding mechanism of the pressure member are separately provided.

  Next, with reference to FIG. 7, the lens barrel (lens apparatus) provided with the vibration wave motor 1 in the present embodiment will be described. FIG. 7 is a cross-sectional view of an essential part of the imaging device 10. Note that, since the lens barrel is substantially rotationally symmetric, only the upper half (the upper side of the optical axis OA) of the imaging device 10 is shown in FIG.

  As shown in FIG. 7, the imaging device 10 is configured to include a camera body 2 and a lens barrel (lens device) 3 that is detachable from the camera body 2. However, the present embodiment is not limited to this, and is also applicable to an imaging device in which a camera body and a lens barrel are integrally configured.

  The camera body 2 has an imaging device 4 such as a CMOS sensor or a CCD sensor. The imaging device 4 photoelectrically converts an optical image formed through an optical system (imaging optical system) including the lenses G1 to G3 and outputs image data. The lens barrel 3 is fixed to the mount 5 of the camera body 2. The lens barrel 3 has a fixed barrel 6. The front barrel 7 holding the lens G1 and the rear barrel 8 holding the lens G3 are fixed to the fixed barrel 6. The lens barrel 3 has a lens holding frame (focus lens holding frame) 9. The lens holding frame 9 holds a lens (focus lens) G2. The lens holding frame 9 is held by the guide bar 12 held by the front barrel 7 and the rear barrel 8 so as to be able to move straight in the direction (optical axis direction) along the optical axis OA. A flange (not shown) is formed on the base plate 115 of the vibration wave motor 1 and is fixed to the rear barrel 8 with a screw or the like.

  With such a configuration, when the movable portion including the vibrator holding member 102 of the vibration wave motor 1 is driven, the driving force of the vibration wave motor 1 causes the vibrator holding member 102 and the second guide member (moving member) 112 to It is transmitted to the lens holding frame 9 via the lens. The lens holding frame 9 is guided by the guide bar 12 and moves rectilinearly.

  According to the present embodiment, a compact vibration wave motor, a lens device, and an imaging device can be provided.

  As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

100 vibrator 101 vibrator 103 piezoelectric element 104 friction member 111 pressure member 112 a pressure holding portion 118 guide means

Claims (11)

A vibrator comprising a piezoelectric element and a vibrator;
A friction member in frictional contact with the vibrator;
A pressure member for pressing the vibrator to the friction member;
And guide means for linearly guiding relative movement between the vibrator and the friction member,
The vibrator and the friction member move relative to each other by vibration generated in the vibrator,
The vibration wave motor characterized in that the guide means has a pressure holding portion for holding the pressure member. The guide means is
A rolling member,
A first guide member rotatably holding the rolling member and fixed;
And a second guide member that holds the rolling member in a rollable manner and is movable.
The rolling member is sandwiched by the first guide member and the second guide member,
The oscillatory wave motor according to claim 1, wherein the second guide member includes the pressing and holding unit. The second guide member has a rolling holding portion for holding the rolling member,
The vibration wave motor according to claim 2, wherein the pressure holding unit is disposed to face the rolling holding unit. When viewed from the direction orthogonal to the pressing direction of the pressing member, the first guide member overlaps at least a part of the pressing member,
The vibration wave motor according to claim 2 or 3, wherein the first guide member is provided with an opening into which the friction member is inserted.   The first guide member is a pressure that holds the first end of the pressure member on the side of connection with the second guide member in the pressure direction of the pressure member, and a pressure that holds the pressure member. The vibration wave motor according to any one of claims 2 to 4, wherein the vibration wave motor is arranged between the holding member and the second end on the connection side.   The second guide member is disposed at a position further away from the first guide member with respect to the vibrator in the pressing direction of the pressing member. The oscillatory wave motor according to any one of 5. The pressure member has a first hook portion held by the second guide member,
The rolling member is arranged so as to pass through the inside of the first hook portion when the vibrator and the friction member move relative to each other. The vibration wave motor according to any one of the items. The pressure member has a coil portion,
The oscillatory wave motor according to claim 7, wherein a diameter of the coil portion increases toward the first hook portion.   The vibration wave motor according to any one of claims 1 to 8, wherein the vibrator and the friction member move relative to each other by ultrasonic vibration generated in the vibrator. A vibration wave motor according to any one of claims 1 to 9,
And an optical system driven by the vibration wave motor. A lens apparatus according to claim 10;
An imaging device for photoelectrically converting an optical image formed through the lens device;