JP6271901B2 - Ultrasonic motor and optical apparatus equipped with ultrasonic motor - Google Patents

Description

  The present invention relates to an ultrasonic motor applied to a digital camera and the like, and an optical apparatus including the ultrasonic motor.

  2. Description of the Related Art Conventionally, in this type of ultrasonic motor and optical apparatus with an ultrasonic motor, a technique for driving a sliding member by pressing a vibrator that periodically vibrates by application of a high-frequency voltage to the sliding member is known.

JP 2001-292484 A

  However, in the prior art disclosed in the above-mentioned patent document, the function of supporting the vibration node of the vibrating body 14 (corresponding to the vibrator of the present case) and the vibration body and the rail 11a (sliding of the present case) by pressurizing the vibrating body. The spring member 17 and the plurality of rubber sheets 15, 16, and 18 have a function of generating a frictional force (corresponding to a member), and the spring member 17 is placed between the fixing plate 19 and the vibrating body 14 with rubber. It is installed via a sheet.

  For this reason, for example, when an impact force is applied due to vibration drop or the like, the so-called wobbling operation, which is a focusing operation by a minute reciprocating motion, and the inertial force by acceleration / deceleration at the time of starting and stopping, etc. The relative position of the plate is shifted, and there arises a problem that the position in the driving direction of the vibrating body 14 with respect to the rail 11a cannot be controlled with high accuracy. There is no technical disclosure regarding how to solve this problem.

  Accordingly, an object of the present invention is to provide an ultrasonic motor that can be driven with high accuracy and an optical apparatus including the ultrasonic motor.

In order to achieve the above object, an ultrasonic motor of the present invention includes a vibrator that vibrates ultrasonically when a high-frequency voltage is applied, and a sliding that is movable relative to the vibrator when the vibrator is pressurized. A member, a base on which the vibrator is fixed, a support member that holds the base and supports the vibrator so as to advance and retreat, and a connecting member that connects the base and the support member. The connecting member has the base and the support member so that there is no backlash in the moving direction of the sliding member and flexibility in the direction in which the vibrator is pressed against the sliding member. It is connected.
In order to achieve the above object, an optical apparatus including the ultrasonic motor of the present invention includes an ultrasonic motor and a lens holder that is held by a guide bar so as to be movable in the optical axis direction and has a focusing lens. The sliding member is sandwiched between the vibrator and the lens holder, and the lens holder is moved in the moving direction of the sliding member by driving the ultrasonic motor, so that the focusing lens is optically moved. It is characterized by moving in the axial direction and performing a focusing operation.

  By configuring as described above, unlike the conventional example, the position of the vibrator does not shift due to the effects of drop impact, wobbling, inertial force due to acceleration / deceleration, etc. It is possible to provide an ultrasonic motor that can be driven smoothly and an optical device including the ultrasonic motor.

It is a principal part disassembled perspective view of the optical apparatus provided with the ultrasonic motor which shows 1st Example of this invention. It is a perspective view which shows the structure of the principal part of an ultrasonic motor. It is an expansion perspective view of a connection member. It is a principal part disassembled perspective view of the optical apparatus provided with the ultrasonic motor which shows 2nd Example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same parts are denoted by the same reference numerals.

[First embodiment]
FIG. 1 is an exploded perspective view of an essential part of an optical apparatus equipped with an ultrasonic motor, showing a first embodiment of the present invention. The optical apparatus has a focus drive mechanism applied to an ultrasonic motor and a digital camera. The rectangular vibrator 101 includes joined portions 101e at both ends in the longitudinal direction. The joined portion 101e is fixed to the joining portion 102b of the base 102 by welding or the like, and thereby the vibrator 101 is fixed to the base 102.

  The connecting member 103 includes a fixed hole portion 103a, and the connecting member 103 is fixed to the base 102 by inserting the screw 104 into the screw hole 102a formed in the fixed hole portion 103a and the base 102. . The support member 105 that supports the vibrator 101 includes a screw portion 105 b, and the support member 105 is fixed to the connection member 103 by inserting the screw 106 through the screw portion 105 b and the fixed hole portion 103 b of the connection member 103. .

  FIG. 2 is a perspective view showing a configuration of a main part of the ultrasonic motor. As shown in FIG. 2, the vibrator 101 constituting the main part of the ultrasonic motor is constituted by a vibrator body 101a and piezoelectric elements 101c and 101d. The piezoelectric elements 101c and 101d are set so that when a high frequency voltage is applied, the vibrator body 101a resonates by ultrasonic vibration in the longitudinal direction and the lateral direction, respectively.

  As a result, the tip of the pressure contact portion 101b formed on the vibrator body 101a causes an elliptical motion as shown in FIG. 2, and rotates by changing the frequency and phase of the high-frequency voltage applied to each of the piezoelectric elements 101c and 101d. Desired motion can be generated by appropriately changing the direction and ellipticity ratio. Therefore, a relative driving force is generated by a frictional force with the sliding member 107 (see FIG. 1) that is movable (slidable) relative to the vibrator 101 in contact with the piezoelectric elements 101c and 101d. The child 101 itself can be moved back and forth along the optical axis.

  Referring now to FIG. 1, the roller holder 108 includes a plurality of rotating rollers 109 that are sliding resistance reducing members. The roller 109 is rotatably fixed by a roller pin 110. The engaged portion 108a of the roller holder 108 is engaged with the engaging claw portion 105a of 105 at the time of assembly, and the sliding member 107 is clamped between the press contact portion 101b and the roller 109. As a result, when the vibrator 101 moves back and forth along the optical axis, the roller 109 rolls on the contact surface of the sliding member 107, and the vibrator 101 can move forward and backward along the optical axis without resistance. Making it possible.

  The lens holder 11 is an optical element, forms a part of a photographing lens applied to an optical device such as a digital camera, and includes a focusing lens 111b that moves in the optical axis direction and performs a focusing operation. . The lens holder 111 is supported by two guide bars 112 and 113 so as to advance and retreat in the optical axis direction. The guide bars 112 and 113 are arranged in parallel with each other across the lens holder 111 and above and below the lens holder 111. The guide bars 112 and 113 are preferably arranged in parallel to the optical axis.

  A driving protrusion (not shown) formed on the support member 105 is engaged with the driven portion 111a of the lens holder 111 provided on the guide bar 112 side. Thus, when the ultrasonic motor is driven, the lens holder 111 can be driven and controlled to a predetermined position in the optical axis direction. The guide bars 112 and 113 and the sliding member 107 are held by a known fixing means on a ground plate (not shown). The guide bar 112 and the lens holder 111 constitute a focus driving mechanism applied to the digital camera.

  A pressure plate 114 that pressurizes the vibrator 101 is provided between the base 102 and the connecting member 103. As will be described later, a plurality of pressure arm portions 103 c (see FIG. 3) provided on the connecting member 103 abuts on the pressure plate 114 and applies a pressing force to the contact surface of the pressure plate 114. There are at least two pressing arm portions 103c.

  The pressure plate 114 is sized to loosely fit into a through hole 102 c provided in the base 102. For this reason, the pressure applied to the pressure plate 114 from the pressure arm 103 c is directly applied to the vibrator 101 without going through the base 102.

  As a result, by pressing the vibrator 101 against the sliding member 107 with a necessary load, a frictional force is generated, and the vibrator 101 itself can be advanced and retracted along the optical axis as described above.

  FIG. 3 is an enlarged perspective view of the connecting member. As described above, the fixed hole 103a of the connecting member 103 and the base 102 to which the vibrator 101 is welded are fastened by the screw 104 (see FIG. 1). Further, the mounting screw portion 105 b and the fixed hole portion 103 b of the support member 105 are fastened by the screw 106.

By this fastening, the connecting member 103 has sufficient flexibility by the function of the arm portion 103f in the pressurizing direction with respect to the support member 105, and is supported without play in the optical axis direction that is the moving direction of the sliding member 107. Has realized that. Therefore, unlike the conventional example, it is possible to prevent the position of the vibrator 101 from being displaced and the feed control accuracy from being deteriorated due to the influence of drop impact, wobbling, inertial force due to acceleration / deceleration, and the like.

  As described above, a plurality of pressure arm portions 103 c are formed inside the space defined by the fixed hole portions 103 a provided at the four corners of the connecting member 103. The pressurizing arm portion 103c includes a first extension portion 103d extending along the optical axis from the vicinity of the fixed hole portion 103b, and a second extension portion extending in the opposite direction by folding back at the tip. 103e. This realizes a spring having a small spring constant even in a limited space. The pressurizing arm portion 103c, the first extending portion 103d, and the second extending portion 103e constitute a pressurizing unit. Further, the tip portion 103g of the pressure arm portion 103c constitutes a pressure portion.

  In the connecting member 103, the four distal end portions 103g of the pressure arm portion 103c are arranged in the direction of the pressure plate 114 (from the plane that the bottom surface of the fixed hole portion 103a defines so that the pressure plate 114 can be surely contacted. It is provided to protrude a predetermined distance in the pressurizing direction).

  In the assembled state, since the locked portion 108a of the roller holder 108 and the locking claw portion 105a of the support member 105 are engaged, the pressure arm portion 103c of the connecting member 103 vibrates via the pressure plate 114. A force for pressing (pressing) the child 101 against the sliding member 107 is generated.

  As a result, the pressure contact portion 101b of the vibrator 101 is pressed and held against the sliding member 107, generates a relative driving force by the action of the high frequency voltage applied to the vibrator 101, and moves the vibrator 101 itself along the optical axis. It is possible to move forward and backward. At this time, the sliding frictional resistance due to the reaction force of the pressing force is reduced by the action of the roller 109, and the loss of the driving force can be avoided.

[Second Embodiment]
FIG. 4 is an exploded perspective view of an essential part of an optical apparatus equipped with an ultrasonic motor, showing a second embodiment of the present invention. The optical apparatus has a focus drive mechanism applied to an ultrasonic motor and a digital camera.

  Since the configuration is almost the same as the first embodiment, only the connection member 401 and the coil spring 402 for pressurization having different configurations will be described. Other members having the same function are denoted by the same reference numerals as in FIG.

The fixed hole 401a of the connecting member 401 and the base 102 to which the vibrator 101 is welded are fastened by screws (not shown) as in the first embodiment. Further, the mounting screw portion 105c (see FIG. 4) of the support member 105 and the fixed hole portion 401b are fastened by screws (not shown). By this fastening, the connecting member 401 is sufficiently flexible by the function of the arm portion 401c in the pressurizing direction with respect to the supporting member 105 as in the first embodiment, and is supported without play in the optical axis direction. Is realized. Therefore, similarly to the first embodiment, it is possible to prevent the position of the vibrator 101 from being displaced due to the impact of drop impact, wobbling, acceleration / deceleration, and the like, thereby preventing the feed control accuracy from being deteriorated.

  A plurality of coil springs 402 as pressure means are provided below the connecting member 401. In the second embodiment, two coil springs 402 are provided, but this number is not limited to two, and other numbers may be used.

The coil spring 402 is disposed between the two arm portions 401 c of the connecting member 401, and one end is supported by the wall on the back side of the upper surface of the support member 105 and the other end is supported by the spring receiving portion 403 a of the pressure plate 403. In the assembled state, as in the first embodiment, since the locked portion 108a of the roller holder 108 and the locking claw portion 105a of the support member 105 are engaged, the coil spring 402 is compressed and the pressure plate 403 is compressed. The force which presses the vibrator | oscillator 101 to the sliding member 107 via is generated. It suffices that at least two arm portions 401c are provided, and two or more arm portions 401c may be provided.

  The pressure plate 403 is sized to loosely fit into a through hole 102 c provided in the base 102. Therefore, the pressing force applied from the coil spring 402 to the pressure plate 403 is directly applied to the vibrator 101 without passing through the base 102.

  As a result, the pressure contact portion 101b of the vibrator 101 is pressed against the sliding member 107, generates a relative driving force by the action of the high frequency voltage applied to the vibrator 101, and uses the vibrator 101 itself as an optical axis. It is possible to advance and retreat along. At this time, the sliding frictional resistance due to the reaction force of the pressing force is reduced by the action of the roller 109, and the loss of the driving force can be avoided.

  Specific examples of the ultrasonic motor and the optical apparatus including the ultrasonic motor according to the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and is shown in the scope of the claims. Any form can be used.

The connecting member 103 that pressurizes the vibrator 101 against the sliding member 107 can be integrated with or separate from the pressing means.

  Improve the controllability and reliability of optical equipment.

101 vibrator 102 base 103, 401 connecting member 104, 106 screw 105 support member 107 sliding member 108 roller holder 109 roller 110 roller pin 111 lens holder 112, 113 guide bar 114, 113 pressure plate 402 coil spring

Claims (6)

A vibrator that vibrates when a high-frequency voltage is applied;
A sliding member in which the vibrator is pressurized and relatively movable with respect to the vibrator;
A base on which the vibrator is fixed;
A support member that holds the base and supports the vibrator so as to freely advance and retract;
A connecting member that connects the base and the support member;
The connection member is fixed to the base, and the support member is connected to the connection member to be connected,
The connecting member connects the base and the supporting member so that there is no backlash in the moving direction of the sliding member and flexibility in the direction in which the vibrator is pressed against the sliding member. A vibration motor characterized by that. The vibration motor according to claim 1,
The connecting member has an arm portion extending in a direction in which the vibrator and the sliding member relatively move,
The tip of the arm is fixed to the base,
A vibration motor comprising pressurizing means for pressurizing the vibrator to the sliding member, wherein the pressurizing means is provided integrally with or separately from the connecting member. The vibration motor according to claim 2,
The vibration motor characterized in that the pressurizing means is provided integrally with the connecting member. The vibration motor according to claim 2 or 3,
The arm portions provided on the connecting member are disposed in at least two places,
The vibration motor is characterized in that the pressurizing means is disposed between the two arm portions. The vibration motor according to any one of claims 1 to 4,
The vibration motor is an ultrasonic motor in which the vibrator is ultrasonically vibrated by application of a high frequency voltage. A vibration motor according to any one of claims 1 to 5,
A lens holder that is held movably in the optical axis direction by a guide bar and has a focusing lens;
The sliding member is sandwiched between the vibrator and the lens holder, and the lens is moved in the moving direction of the sliding member by driving the vibration motor, whereby the focusing lens is moved to the optical axis. An optical apparatus characterized by moving in a direction to perform a focusing operation.

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