JP2014054033A - Vibration wave drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable rod-like ultrasonic vibrating body capable of preventing conduction failure caused by cut-off of a flexible printed board without introducing performance deterioration of a vibrating body.SOLUTION: In a vibrating body having a third elastic body that extends in a direction orthogonal to an axial direction of the vibrating body and includes a slide surface on which a movable body slides outside an outer diameter of an electro-mechanical energy conversion element, and a second elastic body that includes an outer diameter outside the outer diameter of the electro-mechanical energy conversion element, an end part of a cover coat for insulation coating a copper foil conductive part of a flexible printed board is disposed inside the outer diameter of the second elastic body.

Description

  The present invention relates to a vibration wave drive device, which forms an elliptical motion on the surface of a vibrating body by an electro-mechanical energy conversion element, and is used in a so-called super lens used for a camera lens or OA device that relatively moves the vibrating body and the moving body. The present invention relates to a sonic motor.

  A vibration wave actuator that vibrates a vibrating body by a strain generating element that generates mechanical distortion in response to an applied electric field or magnetic field, converts the vibration of the vibrating body into a continuous or intermittent mechanical motion, and outputs the vibration ( The vibration wave driving device) is currently used in various fields.

  Among the piezoelectric actuators using the piezoelectric element, an actuator called an ultrasonic motor can constitute a continuous rotation type rotational drive source.

  For this reason, this is already mounted in an optical device such as a camera as a drive source in place of the conventional rotary electromagnetic drive motor, and the drive control technology for such an ultrasonic motor has been almost established.

  Thus, although the technique regarding an ultrasonic motor is almost established, the technique which improves the reliability of a motor needs further improvement.

  A vibration wave driving device (ultrasonic motor) that excites vibrations of the same bending mode in a plurality of different planes is disclosed in, for example, Patent Document 1 and the driving principle and the like are described in detail in these. The vibrator disclosed in these is composed of an electromechanical energy conversion element and an elastic member. The vibrating body has an electro-mechanical energy conversion element sandwiched and fixed by elastic members from both sides.

  Such a vibration wave driving device that excites vibrations of the same shape in bending mode in a plurality of different planes generates an elliptical motion in the surface particles of the vibrating body, and continuously drives the moving body in pressure contact therewith. Thus, driving is possible.

  A pattern electrode is formed on the piezoelectric element, and a substantially sine wave AC voltage having a time phase of 90 ° is sequentially applied to each electrode.

  When an AC voltage is applied at a frequency near the natural frequency of the vibration mode to be excited, the vibrating body resonates due to a bending moment applied to the vibrating body due to expansion and contraction of the piezoelectric element.

  The vibration modes excited with respect to alternating voltages different by 90 ° have the same shape and different phases, and an elliptical motion is formed on the surface particles of the vibrating body by synthesis. Since the vibration wave driving device that excites the vibration of the same bending mode in a plurality of different planes is a mode in which the vibration mode has the same deformation distribution, the resonance frequency hardly changes depending on the vibration direction. There is a feature that almost no adjustment is required to match the resonance frequencies of the two.

Japanese Patent Laid-Open No. 4-91671

  FIG. 7 shows a configuration of a conventional vibrating body. The piezoelectric element 103 and the flexible printed circuit board 104 are disposed between the first elastic body 101A, the third elastic body 101C, and the second elastic body 101B. The outer diameters of the first elastic body, the second elastic body, the third elastic body, the piezoelectric element 103, and the holding portion 104A are processed to substantially the same dimensions. The end portion 104D1 of the cover coat portion 104D on the piezoelectric element side of the flexible printed circuit board 104 is disposed outside the outer diameter portion of the piezoelectric element 103. In the flexible printed circuit board 104, a conducting part 104 </ b> B extends from a clamping part 104 </ b> A that is clamped and clamped between the second elastic body 101 </ b> B constituting the vibrating body 100 and the piezoelectric element 103. The extending end of the conducting portion 104B has a connecting portion 104C for connecting to a not-shown conducting connector, and is covered with the cover coat portion 104D for electrical insulation except for necessary portions. Yes.

  In the configuration of the vibrating body and the flexible printed circuit board of the conventional example, cutting is performed at a portion not covered with the cover coat portion 104D of the conductive portion 104B of the protruding portion from the vibrating body of the flexible printed circuit board when assembling the rod-shaped ultrasonic vibrating body. As a result, poor conduction occurred. A portion of the conductive portion 104B that is not covered with the cover coat portion 104D is likely to bend the flexible printed circuit board at a right angle, particularly in the direction indicated by the arrow.

  It is also conceivable to reinforce with an elastic member such as an adhesive so that bending stress or the like is not applied to the portion of the flexible printed circuit board 104B that is not covered with the cover coat portion 104D. However, applying an adhesive corresponds to applying a damping component to the vibrator. Since this vibrating body converts electrical energy into mechanical vibration energy and obtains a mechanical output, an increase in energy for vibration leads to a decrease in performance of the vibrating body, which is not desirable.

  An object of the present invention is to provide a highly reliable rod-shaped ultrasonic vibration body that prevents conduction failure due to breakage of a flexible printed circuit board without degrading the performance of the vibration body.

  In the vibration wave driving device of the present invention, an electromechanical energy conversion element is provided between the first elastic body and the second elastic body via a third elastic body disposed on the first elastic body side. The vibrator and the vibrator are brought into contact with each other and moved relative to the vibrator by a traveling wave excited by the vibrator by applying a driving signal to the electromechanical energy conversion element through a flexible printed board. A vibration wave drive device having a moving body, wherein the sliding surface extends in a direction orthogonal to the axial direction of the vibrating body, and the moving body slides outside the outer diameter of the electro-mechanical energy conversion element. And a vibrating body having a second elastic body having an outer diameter outside the outer diameter of the electro-mechanical energy conversion element, wherein the copper foil conduction portion of the flexible printed board is Insulating coating And wherein placing the ends of the cover coat to the inside of the outer diameter of the second elastic body.

  A cutting prevention means is provided so that the stress at the end of the cover coat is dispersed.

  The cutting prevention means is characterized in that the end portion of the cover coat is formed in a curved shape.

  The curved shape is formed in a waveform shape.

  The extending part of the flexible printed circuit board from the electro-mechanical energy conversion element is formed in a curved shape.

  ADVANTAGE OF THE INVENTION According to this invention, without applying a reinforcement member etc. to a flexible printed circuit board, the conduction defect by the cut of a flexible printed circuit board can be prevented simply and cheaply, and a reliable vibrating body can be provided.

The figure which shows the structure of the vibrating body of Example 1 of this invention. The top view of the flexible printed circuit board used in Example 1 of the present invention The top view of the flexible printed circuit board used in Example 2 of the present invention The top view of the flexible printed circuit board used in Example 3 of the present invention The figure which shows the structure of the vibrating body of Example 4 of this invention. The figure which shows the structure of the vibration wave drive device of this invention The figure which shows the structure of the conventional vibrating body

  The mode for carrying out the present invention will be described with reference to the following examples.

[Example 1]
As a first embodiment, a configuration example of a vibration wave driving device that causes an elliptical motion in a friction drive unit of a vibrating body and relatively moves a moving body that contacts the friction drive unit of the vibrating body will be described.

  First, an example of the configuration of the vibration type motor 100 will be described with reference to FIG.

  In FIG. 6, reference numeral 100 denotes a vibration wave driving device (vibration type motor).

  The shaft 106 is inserted into a through hole provided at the center of the first elastic body 101A, the third elastic body 101C, the piezoelectric element 103, the flexible substrate 104, and the second elastic body 101B. A step is provided in the middle of the shaft 106, and this step hits a step provided on the inner wall of the first elastic body 101A. A screw is formed at the tip (lower end) portion of the shaft 106, and the first fastening member 105A, which is a fastening member, is fitted to the screw and tightened. Thereby, the 2nd elastic body 101B, the flexible printed circuit board 104, the piezoelectric element 103, the 3rd elastic body 101C, and the 1st elastic body 101A can be fixed. On the side of the third elastic body 101C that comes into contact with the piezoelectric element 103, a recess 115 is provided so that they are in contact with each other on the outer periphery.

  The contact spring 108 fixed to the rotor 107 that is the moving body 102 is in pressure contact with the surface of the friction drive unit 112 on the side that is not in contact with the piezoelectric element 103 of the third elastic body 101C.

  The contact spring 108 has elasticity, is fixed to the rotor 107 and rotates integrally. Reference numeral 109 denotes a gear (output member) as an output means, which allows the rotor 107 to move in the direction of the rotation axis and is fitted with the rotor 107 and two detents 113 so as to follow the movement of the rotor 107 in the rotational motion. Match. Reference numeral 110 denotes a pressurizing unit such as a coil spring, which is disposed between the spring receiving portion 114B of the rotor 107 and the spring receiving portion 114A of the gear 109, and pressurizes the rotor 107 so as to push it down toward the third elastic body 101C. ing.

  The gear 109 is axially supported by a fixed member 111 coupled to the shaft 106, and the position in the axial direction is regulated by the fixed member 111.

  A screw is also formed at the tip (upper end) portion of the shaft 106 that is not fitted with the first fastening member 105A. The second fastening member 105B is fitted to this screw, and the shaft 106 is fixed to the fixing member 111. Is fixed.

  The fixing member 111 is provided with a screw hole, and the vibration type motor can be attached to a desired location by fixing the fixing member 111 to the desired location using a screw.

  For example, as described in a patent document (Japanese Patent No. 3416233), the piezoelectric element 103 has electrode films formed on both sides of one piezoelectric body, and the electrode film on one side is divided into four electrode films. , A (+), A (−), B (+), and B (−) phases.

  The four regions where the electrode films are formed are polarized in the thickness direction of the piezoelectric element 103 so that A (+) and A (−) and B (+) and B (−) are opposite to each other. , A phase, and B phase.

  When a drive signal is applied to the one group electrode, one region of the piezoelectric element 103 expands in the thickness direction and the other region contracts in the thickness direction.

  In addition, a drive signal whose phase is shifted by 90 degrees is applied to the other group of piezoelectric bodies.

  Then, the vibration body has two bending vibrations such that the first elastic body 101A is swung left and right (one is a direction in which the amplitude direction is perpendicular to the axial direction of the shaft 106, and the other is 90 degrees from the other direction. Phase out of phase) occurs.

  When these vibrations are combined, elliptical motion is formed in the friction drive unit 112 on the surface of the third elastic body 101C.

  If the contact spring 108 is brought into pressure contact with the friction drive unit 112 on the surface of the third elastic body 101C where the elliptical motion is excited, the moving body 102 including the contact spring 108 and the rotor 107 is subjected to the elliptical motion. Move as if pushed out.

  Next, the configuration of the vibrator in the present embodiment will be described with reference to FIGS. 1 and 2.

  The piezoelectric element 103 and the flexible printed circuit board 104 are disposed between the first elastic body 101A, the third elastic body 101C, and the second elastic body 101B. The outer diameter of the second elastic body 101B is configured to be larger than the outer diameter of the piezoelectric element 103. An end portion 104D1 of the cover coat portion 104D on the piezoelectric element side of the flexible printed circuit board 104 is disposed inside the outer diameter portion of the second elastic body. With such a configuration, it is almost impossible to bend at a right angle during assembly at a portion not covered by the cover coat portion 104D of the conductive portion 104B protruding from the vibrating body of the flexible printed circuit board 104, and cutting due to stress concentration. Can be prevented. FIG. 2 is a top view of the flexible printed circuit board 104 of FIG. The end portion 104D1 on the clamping portion 104A side of the cover coat portion 104D is configured in a linear shape. The outer diameter of the piezoelectric element 103 is processed so as to be smaller than the outer diameter of the sandwiching portion 104A as indicated by a dotted line.

[Example 2]
As a second embodiment, a configuration example different from the first embodiment will be described with reference to FIG.

  The flexible printed circuit board 104 has a conducting part 104B extending from a clamping part 104A that is fastened and clamped. The extending end of the conducting portion 104B has a connecting portion 104C for connecting to a not-shown conducting connector, and is covered with the cover coat portion 104D for electrical insulation except for necessary portions. Yes. The end portion 104D1 on the clamping portion 104A side of the cover coat portion 104D is formed in an arc shape. With such a configuration, stress concentration at the end portion 104D1 of the cover coat portion 104D can be reduced as compared with the linear shape.

[Example 3]
As a third embodiment, a configuration example having a different form from the first and second embodiments will be described with reference to FIG.

  The flexible printed circuit board 104 has a conducting part 104B extending from a clamping part 104A that is fastened and clamped. The extending end of the conducting portion 104B has a connecting portion 104C for connecting to a not-shown conducting connector, and is covered with the cover coat portion 104D for electrical insulation except for necessary portions. Yes. The end portion 104D1 on the clamping portion 104A side of the cover coat portion 104D is formed in a waveform shape. By adopting such a configuration, stress concentration at the end portion 104D1 of the cover coat portion 104D can be reduced as compared with the arc shape.

[Example 4]
As a fourth embodiment, a configuration example different from the first, second, and third embodiments will be described with reference to FIG.

  The piezoelectric element 103 and the flexible printed circuit board 104 are disposed between the first elastic body 101A, the third elastic body 101C, and the second elastic body 101B. The outer diameter of the second elastic body 101B is configured to be larger than the outer diameter of the piezoelectric element 103. Then, the flexible printed circuit board 104 is formed in an arc shape starting from a position where the flexible printed circuit 104 comes into contact with the outer diameter portion of the piezoelectric element 103. Is fixed.

  With this configuration, it is possible to relieve stress caused by contact between the edge of the second elastic body and the flexible printed circuit board due to vibration of the vibrating body and tensile stress caused by vibration of the vibrating body.

100 Vibration wave drive (vibration type motor)
101A, 101B, 101C Elastic body 102 Moving body 103 Piezoelectric element 104 Flexible printed circuit board 104A Nipping part 104B Conducting part 104C Connection part 104D Cover coat part
104D1 Cover coat end 105A, 105B Tightening member 106 Shaft 107 Rotor 108 Contact spring 109 Gear (output member)
110 Spring 111 Fixing member 112 Friction drive part (sliding surface)
113 Detents 114A, 114B Spring receiving portion 115 Recess 116 External member

Claims (5)

Via a third elastic body arranged on the first elastic body side, a vibrating body provided with an electromechanical energy conversion element between the first elastic body and the second elastic body, and contact with the vibrating body And a vibration wave drive device having a moving body that moves relative to the vibration body by a traveling wave excited by the vibration body by applying a drive signal to the electro-mechanical energy conversion element through a flexible printed board. A third elastic body having a sliding surface extending in a direction orthogonal to the axial direction of the vibrating body and on which the moving body slides outside the outer diameter of the electro-mechanical energy conversion element; In the vibrating body having the second elastic body having an outer diameter outside the outer diameter of the electro-mechanical energy conversion element,
An oscillatory wave drive device characterized in that an end portion of a cover coat for insulatingly covering the copper foil conducting portion of the flexible printed board is disposed inside the outer diameter of the second elastic body. 2. The vibration wave driving device according to claim 1, wherein a cutting prevention means is provided so that the stress at the end of the cover coat is dispersed. The vibration wave driving device according to claim 1, wherein the cutting prevention means configures an end portion of the cover coat in a curved shape. 4. The vibration wave driving device according to claim 1, wherein the curved shape is formed in a waveform shape. 5. The vibration wave drive device according to any one of claims 1 to 4, wherein an extended portion of the flexible printed circuit board from the electro-mechanical energy conversion element is formed in a curved shape.