JP5717822B2 - Vibration wave motor - Google Patents

Description

  The present invention relates to a vibration wave motor, and more particularly to a vibration wave motor characterized by a support structure for a vibrator.

  Conventionally, ultrasonic motors (vibration wave motors) of various structures such as a rotary type and a linear type have been proposed, but the components of those mechanical parts are basically the same.

  That is, the constituent elements are an elastic body and an electro-mechanical energy conversion element (or magnetostrictive element) constituting the vibrator, a supporting member that supports the vibrator, and a driven body that contacts and frictionally drives a part of the vibrator. And a pressure applying means for applying pressure to the vibrator and the driven body, and a bearing guide member.

  FIG. 8 is a configuration diagram of a linear vibration wave motor according to a conventional example (Patent Document 1). (A) is a front view, (b) is a side view.

  The horizontally-long rectangular parallelepiped piezoelectric element 15 includes a holding member 19 that holds the piezoelectric element 15, a leaf spring 20 that biases the piezoelectric element 15 toward the driven body 17, and a driving contact portion 16 that contacts the driven body 17. And are provided.

  The holding member 19 is formed of a side wall portion 22 that holds the piezoelectric element 15 in the Y direction, a base portion 23, and a substantially cylindrical pin portion 18 that protrudes from the side wall portion 22 in the Y direction.

  Further, since the pin portion 18 is formed in a substantially cylindrical shape, the piezoelectric element 15 is supported so as to be rotatable around the pin portion 18 and can flexibly follow the change of the driven body 17.

  When an alternating electric field is applied to the piezoelectric element 15 by a power source (not shown) and a power supply means, a bending vibration mode in the XZ plane and an expansion / contraction mode in the X direction are simultaneously excited in the vibrator constituted by the piezoelectric element 15. Thus, an elliptical motion is formed in the drive contact portion 16. As a result, the driven body 17 that contacts the driving contact portion 16 by the leaf spring 20 is frictionally driven in the X direction.

  In this conventional example, the linear bearing guide is not shown, but if the upper part (from the members 15 to 23) from the piezoelectric element 15 is the fixed side, the driven body 17 is in the X direction (direction in which the driving force is received). It is guided so that it is restrained.

  The drive system using this linear vibration wave motor has a simple structure and can be directly driven compared to the drive system in which a rotary electromagnetic motor is linearly converted as in the past. It has the effect of improving.

  Patent Document 2 discloses a technique that uses magnetic force as pressurizing means in a linear vibration wave motor.

JP 2006-211839 A JP 2006-340443 A

  The support portion in Patent Document 1 is composed of a pin portion 18, a holding member 19 that engages with the pin portion and restricts the posture of the vibrator, and a leaf spring 20, and presses the vibrator against the driven body 17. Thus, the position and orientation of the vibrator are defined. For this reason, the structure becomes larger in the thickness direction, which is not suitable for downsizing the entire motor.

  In this structure, since there is no damping member between the vibrator-holding member-plate spring, slight leakage vibration due to driving of the vibrator or unnecessary vibration propagated from the friction part at the time of driving becomes an excitation source. There was a problem that it was easy to generate abnormal noise.

  An object of the present invention is to provide a vibration wave motor that can be reduced in size and cost by simplifying and thinning a support structure of a vibrator.

In order to achieve the above object, the vibration wave motor according to claim 1 includes a sheet-like member and a plurality of vibrators provided on the sheet-like member and spaced apart from each other , and the plurality of vibrators. Each has an elastic body and an electro-mechanical energy conversion element connected to the elastic body, and a conductive member is provided between the sheet-like member and each of the plurality of vibrators. Features.

  According to the vibration wave motor of the present invention, the support structure of the vibrator can be simplified and thinned, and the size and cost can be reduced.

1 is a perspective view of a vibration wave motor according to a first embodiment of the present invention. It is sectional drawing of the vibration wave motor of FIG. It is a block diagram of the vibrator | oscillator part which is the principal part of the vibration wave motor which concerns on the 2nd Embodiment of this invention. It is AA sectional drawing of FIG. It is a block diagram of the vibrator | oscillator part which is the principal part of the vibration wave motor which concerns on the 3rd Embodiment of this invention. It is a block diagram of the vibrator | oscillator part which is the principal part of the vibration wave motor which concerns on the 4th Embodiment of this invention. It is a block diagram of the vibrator | oscillator part which is the principal part of the vibration wave motor which concerns on the 5th Embodiment of this invention. It is a block diagram of the linear vibration wave motor which concerns on a prior art example.

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

(First embodiment)
FIG. 1 is a perspective view of a vibration wave motor according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the vibration wave motor of FIG.

  1 and 2, a piezoelectric element 2 as an electro-mechanical energy conversion element is joined to a rectangular elastic body 1 made of a soft magnetic material such as iron. In addition, a flexible printed circuit board 4 (hereinafter referred to as “flexible”) whose base part 4-1 is made of a resin (for example, a polyimide film) is joined to the other surface of the piezoelectric element 2. The elastic body 1 and the piezoelectric element 2 constitute a vibrator.

  Two protrusions 3-1 and 3-2 are formed on one surface of the elastic body 1, and these contact with the contact surface 5-1 of the driven body 5 to generate a frictional driving force.

  The driven body 5 is composed of a permanent magnet magnetized so that the contact surface side is an N pole (or S pole) and the opposite surface side is an S pole (or N pole), and is composed of a soft magnetic body. A suction force is generated between the elastic body 1 of the vibrator and the protrusion 3 (3-1, 3-2), and a pressing force is generated between the two parts.

  The flex 4 includes a base portion 4-1, an electrode portion 4-2 connected to the electrode terminal portion of the piezoelectric element 2, a connect portion 4-4 for electrical connection with an external power feeding portion (not shown), Furthermore, it is comprised by the electroconductive part 4-3 (a) 4-3 (b) which electrically connects these both parts.

  Further, the flex 4 of the present embodiment is provided with a portion to be fixed between the connecting portion 4-4 and the electrode portion 4-2, and is screwed to the housing 7 with screws 6 (6-1, 6-2) or the like. Stop and fix the vibrator.

  When an alternating electric field is applied to the flex 4 from a power source (not shown), a desired vibration is excited in the vibrator, and an elliptical motion is generated in the protrusions 3-1 and 3-2. The body 5 is frictionally driven in the X-axis direction.

  Here, the flex 4 is a power supply source to the piezoelectric element 2 and has a function also serving as a support member for the vibrator.

  This flex 4 is roughly divided into the following three parts.

  First, a vibration part V that is joined to the piezoelectric element 2 and vibrates together with the piezoelectric element 2, a fixing part C that fixes the flexible cable 4 to a housing such as a product, and a position between the vibration part V and the fixing part C. Then, these two parts are connected to each other to support the piezoelectric element 2 (vibrator) (FIG. 1).

  Of particular importance is this support S. The support portion S correctly defines the positional relationship with the driven body 5 at the time of initial assembly, and maintains the correct posture even when the vibrator receives an external force such as a reaction force of the driving force or an inertial force during reversal. Hold as is.

  Further, the support portion S has a flexible characteristic in the follow direction so that the piezoelectric element 2 can always obtain a stable contact state following the undulation of the contact surface 5-1 of the driven body 5 or the like. Is required.

  In order to satisfy these functions, the support portion S is configured to reduce the rotational rigidity around the X axis and the rigidity of the displacement in the Z-axis direction and increase the rigidity in the XY plane.

  Therefore, the conductive part 4-3 (copper foil in the present embodiment) formed on the sheet-like base part 4-1 is used as a reinforcing part, and the conductive part 4-3 (a) of the support part S and 4-3 (b) is arranged so as to be widened to the outer peripheral side in the width direction. Thereby, the rigidity in the XY plane of the flexible film which is a thin film sheet (sheet member) is increased.

  In addition, a cover film or the like is applied to the support portion S to form a laminated structure of sheet members, and by making many interface portions composed of them, unnecessary vibrations propagating through the flex 4 are caused by slipping at these interfaces. It has a damping structure.

  This prevents abnormal noise caused by the vibration of the flex 4 that has been generated in the past, and also prevents leakage vibration of the vibrator from propagating to the housing, amplifying noise, or adversely affecting other sensors. can do.

  In the conventional vibration wave motor, since the support member for transmitting the driving force is made of a highly rigid metal or the like, the parts are large and the motor structure is complicated. However, according to the vibration wave motor of the present embodiment, the motor configuration can be simplified by supporting the piezoelectric element 2 that constitutes the vibrator with the sheet member (support portion S of the flex 4). Can be miniaturized.

(Second Embodiment)
FIG. 3 is a configuration diagram of a vibrator part which is a main part of the vibration wave motor according to the second embodiment of the present invention.

  In the present embodiment, the flex 4 is configured to branch out and extend in both sides (Y direction) and the X direction of the vibrator, and has a support function on both sides in the Y direction, and extends in the X direction. It is the structure which supplies electric power in the part.

  Further, in the present embodiment, in addition to fixing both sides of the flexible cable 4 with screws 6, the flexible resin 4 is sandwiched by pressing plates 8 (8-1, 8-2) to the end portion in the X direction to the casing 7 (7 −1, 7-2) so that the displacement in the XY plane of the vibrator can be constrained.

  4 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 4, the connection unit 4-4 extends in the X direction and then curls in the Z direction to connect to a power supply unit (not shown) and holds the vicinity of the connection unit 4-4 in a housing or the like. So that it is fixed. By doing so, the connecting portion 4-4 composed of a plurality of layers serves as a damping material, and has an effect of suppressing unnecessary vibrations propagating from the piezoelectric element 2 constituting the vibrator to the flex 4.

(Third embodiment)
FIG. 5 is a configuration diagram of a vibrator part which is a main part of a vibration wave motor according to the third embodiment of the present invention.

  This embodiment shows an example in which one of the casings in the second embodiment has a movable structure and tension is applied to the flex 4.

  One housing 7 is fixed and the other housing 9 is movable. The housing 9 is provided with a spring receiving portion 11 for receiving the leaf spring 10, and the leaf spring 10 in the −Y direction with respect to the fixing portion C of the flex 4 sandwiched between the holding plate 8 and the housing 9. A structure in which a spring force is applied. In this way, the tension in the Y direction is applied to the support portion S of the flex 4.

  Thereby, the rigidity in the XY plane of the thin sheet-like support part S can be increased, and the stable vibrator can be supported.

(Fourth embodiment)
FIG. 6 is a configuration diagram of a vibrator part which is a main part of a vibration wave motor according to the fourth embodiment of the present invention.

  In the above-described embodiments, the example has been shown in which the vibrator support portion (support portion S of the flexible cable 4) is a laminated structure of sheets, and vibration is attenuated to prevent abnormal noise and the like. Further, the sheet lamination pattern in the vibration part is devised. This reduces unnecessary vibration of the vibrator.

  The vibrator is composed of a piezoelectric element 2, an elastic body 1 having protrusions 3-1, 3-2, and a flex 4, and when driving the vibrator, a secondary mode of out-of-plane bending and expansion and contraction are performed. It is assumed that the elliptical motion is excited by the synthesis of the primary mode.

  The secondary mode, which is the drive mode, is deformed so that there are three vibration nodes as shown in the lower side of FIG. 6 (M2). The electrode pattern of the piezoelectric element 2 for exciting the secondary mode is a portion of the vibration antinode so that the center of the vibration antinode (arrow (1)) and the center of the electrode coincide with each other as shown by the broken line in the figure. As is well-known, it is good to provide in.

  Here, + and − indicate the direction of polarization in the thickness direction of the piezoelectric element 2.

  On the other hand, in this vibrator, there is a primary mode of out-of-plane bending as one of unnecessary vibrations that are easily excited by friction driving. As shown in the lower side of FIG. 6, the deformation of this mode is a place where the central portion of the piezoelectric element 2 becomes an antinode of vibration, and this portion is effective for exciting vibration and applying damping force. It can be seen that it is.

  This part is a node of vibration for the drive mode and is also a place with little influence.

  Therefore, in the present embodiment, a conductive member formed of copper foil or the like is laminated in the vicinity of the center of the piezoelectric element 2 to form an electrode portion, and a lead member is provided from the vicinity toward the support portion S of the flex 4. The laminated portion was formed near the center in the width direction of the support portion.

  In this way, even when the vibrator is excited in the first-order mode of out-of-plane bending, the laminated vibrating portion and support portion S effectively attenuate only in this mode. Such abnormal noise can be prevented from occurring.

  In this embodiment, in order to reinforce the support part S of the flexible cable 4, the reinforcing members 12 are arranged on both end surfaces, and the damping effect of the support part S is improved together with the reinforcement.

(Fifth embodiment)
FIG. 7 is a configuration diagram of a vibrator part which is a main part of a vibration wave motor according to the fifth embodiment of the present invention.

  In the present embodiment, an example is shown in which a plurality of vibrators are arranged on one sheet, and the structure for driving a large number of units is further simplified.

  Piezoelectric elements 2-10 to 2-13 are bonded to the resin sheet 13 formed in a ring shape by bonding or the like, and a part of the electrode part and the lead part made of a conductive member such as copper foil Is bonded between the sheet 13 and the piezoelectric elements 2-10 to 2-13.

  The lead portions made of a conductive material each extend radially and are joined to four narrow sheet portions integrally provided with the sheet 13 by bonding or the like to form a support portion, and further extend outwardly therefrom. Connection terminal portions 4-10 to 4-13 are formed.

  For fixing to the product body, such as a housing, a part of the radially extending support part is fixed so as to be sandwiched from above and below by the ring-shaped fixing member 14, and the four vibrators are simultaneously supported to set the position. Do.

  As a result, a drive structure for a plurality of vibration wave motors can be realized with a simple structure.

  As described above, by configuring the support portion of the vibrator with a laminate of thin sheet members, the support portion structure can be simplified and reduced in size, and the vibration damping effect in the laminated portion can be positively achieved. By using it, an effect can be obtained even for abnormal sounds that have been a problem in the past.

  In the present embodiment, polyimide sheet is used as an example of the sheet member. However, the present invention is not limited to this material, and it is needless to say that it may be a thin-film organic material. Moreover, although the copper-based lead material has been described as an example of the reinforcing member, the effect can also be obtained by laminating a plurality of resin materials having a higher elastic modulus than the flex.

DESCRIPTION OF SYMBOLS 1 Elastic body 2 Piezoelectric element 3 Protrusion 4 Flexible printed circuit board 5 Driven body 6 Screw 7 Case 8 Holding plate 9 Case (movable)
10 leaf spring 12 reinforcing member 13 sheet member

Claims (8)

A sheet-like member;
A plurality of vibrators provided on the sheet-like member and spaced apart from each other ;
Each of the plurality of vibrators includes an elastic body and an electro-mechanical energy conversion element connected to the elastic body ,
A vibration wave motor, wherein a conductive member is provided between the sheet-like member and each of the plurality of vibrators.   The vibration wave motor according to claim 1, wherein the sheet-like member has a ring shape. Said conductive member, said sheet-like member or al integrally provided with part of the sheet member extending, vibration wave motor according to claim 1 or 2, characterized in that to form the supporting portion .   The said support part is comprised by the laminated body comprised with the said ring-shaped sheet member which consists of organic type materials, and the reinforcement member whose elastic modulus is higher than this laminated body, The characterized by the above-mentioned. Vibration wave motor.   4. The vibration wave motor according to claim 3, wherein the support portion is composed of a ring-shaped sheet member made of resin and a copper-based lead material.   The vibration wave motor according to claim 4, wherein the laminate of the sheet members is made of resin.   The vibration wave motor according to claim 4, wherein the reinforcing member is made of a copper-based lead material.   The vibration wave motor according to claim 1, wherein the sheet-like member is a flexible printed circuit board that is electrically connected to the electromechanical energy conversion element.

Images