JP2017200357A - Vibration wave motor and electronic apparatus mounting vibration wave motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration wave motor in which compaction and improvement of reliability are compatible.SOLUTION: In a vibration wave motor having a transducer, compression means for compressing the transducer against a slide member coming into contact therewith, a transmission member for transmitting a compression force by the compression means to the transducer, and a limit member for limiting the movement range of the transducer, where the transducer and slide member move relatively by a vibration generated in the transducer, the transmission member includes a first abutment part, the limit member includes a second abutment part abutting against the first abutment part, and the transmission member rotates when the transducer moves and the first and second abutment parts collide.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vibration wave motor.

  Vibration wave motors (ultrasonic motors), which are widely used as camera and lens drive sources by taking advantage of features such as high torque output, high positioning accuracy, and quietness, require both miniaturization and improved reliability. ing. Patent Document 1 discloses an ultrasonic motor that can be miniaturized by providing a stopper on a vibrator and restricting a moving range.

JP2015-126692A

  However, in the technique disclosed in Patent Document 1, when an impact is applied to the motor unit, there is a problem that wear or damage is likely to occur between the vibrator and the friction member.

  In view of such a problem, an object of the present invention is to provide a vibration wave motor capable of achieving both reduction in size and improvement in reliability.

  A vibration wave motor according to one aspect of the present invention includes a vibrator, a pressurizing unit that pressurizes the vibrator against a sliding member that contacts the vibrator, and a pressure applied by the pressurizing unit. A vibration wave that includes a transmission member that transmits to the vibrator and a restriction member that restricts a movement range of the vibrator, and the vibrator and the sliding member move relative to each other due to vibration generated in the vibrator. In the motor, the transmission member includes a first contact portion, the limiting member includes a second contact portion that contacts the first contact portion, and the transmission member includes the vibration member. The child moves and rotates when the first contact portion and the second contact portion collide with each other.

  According to the present invention, it is possible to provide a vibration wave motor capable of achieving both reduction in size and improvement in reliability.

It is sectional drawing of an imaging device provided with the ultrasonic motor which concerns on embodiment of this invention. It is a block diagram of an ultrasonic motor. It is explanatory drawing of the limiting method of the movement range of an ultrasonic motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a cross-sectional view of an imaging apparatus that is an electronic apparatus including an ultrasonic motor that is a vibration wave motor according to an embodiment of the present invention. The imaging device of the present embodiment includes an imaging lens unit 1 and a camera body 2. Inside the imaging lens unit 1, an ultrasonic motor 3 and a focusing lens 4 attached to the ultrasonic motor 3 are arranged. An image sensor 5 is disposed inside the camera body 2. The focusing lens 4 is moved in parallel with the optical axis O by the ultrasonic motor 3 during photographing. The subject image is formed at the position of the image sensor 5, and the image sensor 5 generates a focused image. In the present embodiment, the ultrasonic motor 3 is mounted on the imaging apparatus, but the present invention is not limited to this. The ultrasonic motor 3 may be mounted on an electronic device different from the imaging device, for example, a lens barrel that can be attached to and detached from the imaging device. The ultrasonic motor 1 may be used not to move the focusing lens 4 parallel to the optical axis O but to move the shake correction lens in a direction orthogonal to the optical axis O.

  FIG. 2 is a configuration diagram of the ultrasonic motor 3. 2A to 2D are a perspective view, an exploded perspective view, a front view, and a side sectional view of the ultrasonic motor 3, respectively.

  The friction member (sliding member) 101 and the guide support member (rail plate) 113 are fixed to the base plate (base) 112 with screws or the like. The base 112 includes a second contact portion 118 and a fourth contact portion 120 that limit a moving range of the moving portion 121 described later. The pressurizing spring (pressurizing means) 110 is connected at four positions via a spring hook portion provided with a pressure transmitting member (transmitting member) 111 and a driving force transmitting member (movable plate) 115, respectively. A pressing force is applied to cause frictional contact with the friction member 101. The pressure transmission member 111 includes a first contact portion 117. In this embodiment, the pressure spring 110 applies pressure to the vibrator 104 at four positions. However, it is possible that a plurality of pressure means can apply pressure to the vibrator 104 at different positions. For example, the present invention is not limited to this. Further, the pressure applied by the pressure spring 110 is orthogonal to the relative movement direction of the moving unit 121 described later.

  The vibrator 104 includes a diaphragm 102 and a piezoelectric element 103. The diaphragm 102 and the piezoelectric element 103 are fixed with an adhesive or the like. The diaphragm 102 includes a contact portion that is a protruding portion provided on a surface opposite to the surface on the pressure transmission member 111 side, and the contact portion is a friction member in a state in which the contact portion is pressurized by the pressure of the pressure spring 110. 101 is contacted. The piezoelectric element 103 excites ultrasonic vibration by applying a voltage. A resonance phenomenon occurs in the vibrator 104 by exciting ultrasonic vibration in the piezoelectric element 103 in a state where the vibration plate 102 and the piezoelectric element 103 are bonded. At this time, two types of standing waves are generated in the vibrator 104, and a substantially elliptical motion is generated in the contact portion of the diaphragm 102.

  The vibrator holding member (first holding member) 105 holds the vibrator 104 with an adhesive or the like. A pressurizing mechanism holding member (second holding member) 107 that is a holding housing for holding the pressure transmission member 111 includes cylindrical rollers (rolling members) 108 a and 108 b and a leaf spring (biasing member) 109. And is connected to the vibrator holding member 105. The pressurizing mechanism holding member 107 includes a power take-out portion (not shown) and a third contact portion 119 connected to the driven body.

  The elastic member 106 is disposed between the piezoelectric element 103 and the pressure transmission member 111. The elastic member 106 prevents the rotation center portion 116 of the pressure transmission member 111 and the piezoelectric element 103 from coming into direct contact in order to prevent damage to the piezoelectric element 103.

  The pressure mechanism holding member 107 and the movable plate 115 are fixed with screws or the like. The movable plate 115 is formed with three V-groove movement guide portions, and rolling balls 114a to 114c are fitted into the movement guide portions, respectively. The rail plate 113 is formed with three groove-shaped fixed side guide portions. The rolling ball 114 is sandwiched between a moving side guide portion formed on the movable plate 115 and a fixed side guide portion formed on the rail plate 113. In this embodiment, the three fixed-side guide portions formed on the rail plate 113 are two V-grooves and one is a bottomed flat groove, but are grooves in which the rolling ball 114 can roll. I just need it.

  In the present embodiment, in order to reduce the thickness of the ultrasonic motor 3 in the Z-axis direction, a plurality of pressure springs 110 are arranged apart from each other so as to surround the vibrator 104 rather than being stacked on the vibrator 104. Yes. In the present embodiment, the pressurizing spring 110 can be made smaller by generating the pressurizing force with the plurality of pressurizing springs 110. The pressurizing force transmission member 111 is supported by a pressurizing spring 110 so as to be rotatable about a rotation center portion 116. The pressure spring 110 presses the vibrator 104 to the friction member 101 in the direction of arrow D (pressing direction) through the elastic member 106 with the rotation center portion 116 as a pressing point, so that the contact portion of the diaphragm 102 is added. The friction member 101 is brought into contact with the pressure member 110 while being pressurized by the pressure of the pressure spring 110. When a voltage is applied to the piezoelectric element 103 in this state, a substantially elliptical motion generated in the vibrator 104 is efficiently transmitted to the friction member 101. At this time, the moving unit 121 including the vibrator 104, the vibrator holding member 105, the elastic member 106, the pressure mechanism holding member 107, the pressure spring 110, the pressure transmission member 111, and the movable plate 115 has an optical axis O. It can move relative to the friction member 101 in parallel with the (X axis).

  Next, connection means for connecting the vibrator holding member 105 and the pressure mechanism holding member 107 will be described. The connecting means includes rollers 108 a and 108 b and a leaf spring 109. As shown in FIG. 2, the rollers 108 a and 108 b are disposed between the vibrator holding member 105 and the pressure mechanism holding member 107 so as to be movable along the Z axis. The leaf spring 109 is disposed between the pressure mechanism holding member 107 and the roller (second rolling member) 108b and has a biasing force parallel to the X axis. The leaf spring 109 biases the vibrator holding member 105 in the direction of arrow B via the roller 108b, and biases the pressurizing mechanism holding member 107 in the direction of arrow C. Accordingly, the roller (first rolling member) 108a is sandwiched between the vibrator holding member 105 and the pressure mechanism holding member 107.

  With the configuration described above, the vibrator holding member 105 and the pressure mechanism holding member 107 can move along the Z axis by the rolling of the rollers 108a and 108b. Therefore, the vibrator holding member 105 and the pressure mechanism holding member 107 can be connected without hindering the ultrasonic vibration generated in the vibrator 104. Further, since the vibrator holding member 105 and the pressurizing mechanism holding member 107 can be connected without any play in the direction parallel to the X axis, that is, in the moving direction of the moving unit 121, there is no response delay due to play. As a result, driving efficiency can be improved.

  Further, the urging force of the leaf spring 109 is set to be larger than the inertial force due to acceleration / deceleration generated when the driving of the vibrator 104 is started and stopped. Thereby, since the relative displacement along the moving direction of the moving part 121 due to the inertial force at the time of driving does not occur in the vibrator 104 and the vibrator holding member 105, stable drive control can be realized.

  In the present embodiment, the connecting means 116 includes the rollers 108a and 108b and the leaf spring 109, but the present invention is not limited to this as long as it includes a rolling member and a biasing member. For example, a ball or the like may be used instead of the roller.

  In this embodiment, the rollers 108a and 108b are used as the rolling members constituting the connecting means, but the present invention is not limited to this as long as it can move along the Z axis. For example, a ball or the like may be used instead of the roller. In this embodiment, the plate spring 109 is used as the urging member constituting the connecting means. However, the urging member can eliminate the play between the vibrator holding member 105 and the pressure mechanism holding member 107. The present invention is not limited to this as long as it is present.

  Next, a load that occurs when the movement range of the moving unit 121 is limited will be described. The moving unit 121 moves within a predetermined moving range, but in order to restrict the moving range of the moving unit 121 when an impact is applied to the moving unit 121 due to vibration or external force, the moving unit 121 or a non-driving body (not driven) An abutting portion that abuts with (shown) is required. However, when the moving unit 121 collides with the non-driven body, when the weight of the driven body is heavy or a strong impact is applied to the moving unit 121 due to an external force or the like, wear between the vibrator 104 and the friction member 101 occurs. Damage occurs, and the adhesion between the diaphragm 102 and the piezoelectric element 103 is peeled off. For this reason, it is necessary to reduce the impact force applied to the vibrator 104. In the present embodiment, the third contact portion 119 of the pressurizing mechanism holding member 107 is in contact with the fourth contact portion 120 of the base 112 so that the movement range of the moving portion 121 can be limited. is there. However, as described above, the vibrator 104 is connected to the pressure mechanism holding member 107 without any backlash. Therefore, when an impact is applied to the pressure mechanism holding member 107, the vibration is not reduced and the vibration is not reduced. It is transmitted to the child 104. For this reason, wear and damage are likely to occur between the vibrator 104 and the friction member 101, and sufficient reliability cannot be obtained.

  Next, with reference to FIG. 3, a method for limiting the movement range of the moving unit 121 according to the present embodiment will be described. FIG. 3 is an explanatory diagram of a method for limiting the movement range of the moving unit 121. FIG. 3A is a diagram illustrating a state in which the first contact portion 117 of the pressure transmission member 111 is in contact with the second contact portion 118 of the base 112. FIG. 3B is a diagram illustrating a state in which the pressure transmission member 111 rotates around the rotation center portion 116. FIGS. 3C and 3D are diagrams in which some of the components are omitted from FIGS. 3A and 3B for ease of explanation.

  As described above, the moving unit 121 can move relative to the friction member 101 in parallel with the optical axis O (X axis) by the substantially elliptical motion of the vibrator 104. As shown in FIG. 3A, when the moving part 121 moves to the limit position of the moving range, the first contact part 117 of the pressure transmission member 111 is the second contact part 118 of the base 112. Abut. At this time, as shown in FIG. 3B, the pressurizing force transmission member 111 rotates in the direction of arrow E around the axis AA in FIG. The axis A-A is orthogonal to the pressurizing direction (arrow D direction) of the pressing force of the pressurizing spring 110 and the moving direction of the moving unit 121. Strictly speaking, it is not necessary to be orthogonal, and even if it is shifted by several degrees, it is regarded as substantially orthogonal (substantially orthogonal). The pressure spring 110 expands and contracts by the rotation of the pressure transmission member 111. In this embodiment, the pressurizing spring 110 is used as the pressurizing unit. However, the present invention is not limited to this as long as the vibrator 104 can be pressurized and the pressurizing force transmission member 111 can be rotated. Not. For example, an elastic member different from the pressure spring 110 may be used.

  In the present embodiment, as shown in FIG. 3C, in the Z-axis direction, the position of the apex of the rotation center portion 116, that is, the position of the contact point between the pressure transmission member 111 and the elastic member 106, The position of the contact portion 117 is shifted by a predetermined distance ΔZ. With such an arrangement, the pressure transmission member 111 can be easily rotated.

  In the present embodiment, the contact surface that contacts the first contact portion 117 of the second contact portion 118 is formed as an inclined surface having a predetermined angle with respect to the X axis. By forming in this way, the pressurizing force transmission member 111 can be easily rotated. The contact surface of the second contact portion 118 may be a curved surface. That is, the contact surface of the second contact portion 118 may be either one of a slope and a curved surface.

  In the present embodiment, when the movement range of the moving unit 121 is limited, the pressurizing spring 110 expands and contracts by rotating the pressurizing force transmission member 111, so that the impact energy applied to the moving unit 121 is applied to the pressing spring 110. It can be converted into elastic energy. Therefore, the impact load applied to the vibrator 104 can be reduced.

  The above-described energy conversion is simply expressed by the following formula (1).

  Here, M is the mass of the moving part 121, V is the speed of the moving part 121 before the pressure transmission member 111 contacts the base 112, k is the spring constant of the pressure spring 110, and ΔL is the pressure spring. The amount of expansion / contraction of 110, v is the speed of the moving part 121 after expansion / contraction of the pressure spring 110.

  When the first contact portion 117 contacts the second contact portion 118 from the equation (1), the moving speed of the moving portion 121 decreases due to the expansion and contraction of the pressure spring 110, but the moving portion 121 moves due to inertia. Continue. The position and orientation when the moving unit 121 is stopped are required to be highly reproducible and recoverable at the start of the next drive. Therefore, in the present embodiment, after the state shown in FIG. 3B, the third contact portion 119 of the pressurizing mechanism holding member 107 contacts the fourth contact portion 120 of the base 112. Unlike the second contact portion 118, the third contact portion 119 and the fourth contact portion 120 are formed to be orthogonal to the X axis. Strictly speaking, it is not necessary to be orthogonal, and even if it is shifted by several degrees, it is regarded as substantially orthogonal (substantially orthogonal). Therefore, when the third contact portion 119 contacts the fourth contact portion 120, the posture of the moving portion 121 can be corrected, and the moving range of the moving portion 121 can be limited at a desired position. . With this configuration, the moving range of the moving unit 121 can be limited at a desired position in a state where the moving speed of the moving unit 121 is reduced due to the expansion and contraction of the spring 110. The impact force applied to 104 can be reduced.

  As described above, in the present embodiment, it is possible to provide a vibration wave motor capable of both reducing the size and improving the reliability.

  As mentioned above, although 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. For example, although the ultrasonic motor 3 of the present embodiment includes the friction member 101 as a fixed portion that does not move, the vibrator 104 is in frictional contact with a member other than the ultrasonic motor 3 (for example, a part of the lens holding frame). The ultrasonic motor 3 may not include the friction member 101. In the present embodiment, the second abutment portion 118 and the fourth abutment portion 120 are provided on the base 112 that holds the friction member 101, but a member different from the base 112 is used as the vibrator 104 or the like. You may use as a limiting member which restrict | limits the moving range of the moving part 121. FIG. That is, a contact portion is provided on a member different from the base 112, and the second contact portion of the base 112 is positioned at the positions of the second contact portion 118 and the fourth contact portion 120 of the base 112. Instead of 118 and the fourth contact portion 120, a contact portion of a member different from the base 112 may be disposed.

3 Ultrasonic motor (vibration wave motor)
101 Friction member (sliding member)
104 vibrator 110 pressurizing spring (pressurizing means)
111 Pressure transmission member (Transmission member)
112 Base (Restricted member)
117 1st contact part 118 2nd contact part

Claims (11)

A vibrator,
A pressurizing means for pressurizing the vibrator against a sliding member in contact with the vibrator;
A transmission member for transmitting the pressure applied by the pressurizing means to the vibrator;
A limiting member that limits the movement range of the vibrator,
A vibration wave motor in which the vibrator and the sliding member move relatively by vibration generated in the vibrator;
The transmission member includes a first contact portion,
The limiting member includes a second contact portion that contacts the first contact portion,
The transmission member is a vibration wave motor that rotates when the vibrator moves and the first contact portion and the second contact portion collide with each other.   The vibration wave motor according to claim 1, wherein the transmission member is rotatably supported by the pressurizing unit.   3. The vibration wave motor according to claim 1, wherein the transmission member rotates about an axis orthogonal to a pressing direction of the pressing unit and a moving direction of the vibrator.   4. The position according to claim 1, wherein a position of the first contact portion is different from a position of a rotation center of the transmission member in a pressing direction of the pressing unit. Vibration wave motor.   5. The vibration wave according to claim 1, wherein a surface of the second contact portion that is in contact with the first contact portion is one of a slope and a curved surface. motor. A holding member for holding the pressurizing means and the transmission member;
The holding member includes a third contact portion,
The limiting member includes a fourth contact portion that contacts the third contact portion,
6. The third abutting portion abuts on the fourth abutting portion after the first abutting portion abuts on the second abutting portion. The vibration wave motor according to any one of the above.   The vibration wave motor according to any one of claims 1 to 6, wherein the transmission member is rotated by the expansion and contraction of the pressurizing unit.   The vibration wave motor according to claim 1, wherein the pressurizing unit is an elastic member.   The vibration wave motor according to claim 1, wherein the pressurizing unit is a spring.   The said vibrator | oscillator is equipped with the piezoelectric element which excites an ultrasonic vibration by applying the vibration plate and voltage which contact the said sliding member, The Claim 1 characterized by the above-mentioned. Vibration wave motor. An electronic apparatus comprising the ultrasonic motor according to claim 1.