JP2011176938A - Vibration wave motor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent piezoelectric characteristic degradation, cracking, and peeling of a piezoelectric material required for exciting an elastic body. <P>SOLUTION: Multiple projections 201c are formed in either surface 201a of an elastic body 201. The films of the raw material of the piezoelectric material 202 and a stress relaxing body 204 are formed on the other surface 201b of the elastic body 201 in positions corresponding to the projections 201c by an aerosol deposition method. The stress relaxing body 204 is provided with a gap D1 against the piezoelectric material 202 and relaxes stress applied to the piezoelectric material 202 when the piezoelectric material 202 is burned. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vibration wave motor having a piezoelectric body formed by forming and firing a raw material film by an aerosol deposition method, and a method for manufacturing the vibration wave motor.

  In general, a vibration wave motor has an annular vibrating body, and this vibrating body is configured by joining a piezoelectric element to a metal elastic body. When a high-frequency voltage whose phase is different in time is applied to the two-phase electrode group formed on the piezoelectric element, two standing wave vibrations are excited in the elastic body by the vibration of the piezoelectric element, and these two standing waves are excited. Vibrations are combined into traveling waves, and the surface of the elastic body moves elliptically. When the rotating body is brought into pressure contact with the surface of the elastic body, the rotating body can be driven to rotate.

  As the above-described piezoelectric element, there is a method in which a bulk material of PZT (lead zirconate titanate) is machined for cutting or polishing to obtain dimensional accuracy after firing, and then the above-described electrode group is arranged and polarized. It has been put into practical use. Then, the bulk material and the elastic body described above are bonded and integrated using an epoxy or acrylic thermosetting adhesive, and this is used as a vibrating body.

  In recent years, attention has been focused on micro electro mechanical systems (MEMS). In this field, it has been studied to further integrate sensors and actuators using piezoelectric ceramics, and to produce these elements by film formation for practical use. As one of them, an aerosol deposition method, which is known as a film forming technique for ceramics and metals, has attracted attention (see Non-Patent Document 1).

  The aerosol deposition method is a method of forming a film by generating an aerosol from raw material powder, injecting the aerosol onto a substrate, and depositing the powder by collision energy at that time. By using the aerosol deposition method, a piezoelectric body having a thickness of 10 μm or more can be efficiently formed.

  With reference to FIG. 6, an elastic body of a general vibration wave motor and a process of forming a piezoelectric body by an aerosol deposition method and further forming an electrode will be described. FIG. 6A shows a perspective view of the metallic elastic body 101 used for the vibration body of the vibration wave motor as viewed from above. The elastic body 101 is formed in an annular shape and has a plurality of convex portions 101a. The plurality of convex portions 101a are annularly arranged at equal intervals, and a plurality of grooves 101b are formed between them.

  As shown in FIG. 6B, the elastic body 101 has a piezoelectric body 102 formed on the surface of the elastic body 101 opposite to the surface on which the plurality of convex portions 101a are formed by an aerosol deposition method. Be filmed. Thereafter, the piezoelectric body 102 is fired at 500 ° C. to 700 ° C. or more to form a plurality of electrodes 103 having an appropriate shape for exciting the vibration necessary for driving the vibration wave motor, as shown in FIG. To do. Then, by applying an AC voltage to each electrode 103, a traveling wave is excited in the vibrating body 100, and a rotating body (not shown) in contact with the convex portion 101a is rotated.

Jun Akira, “The 3rd exploration of next-generation mechanical design, high-speed ceramic coating using the impact adhesion phenomenon of ultrafine particles”, Mechanical Design, Nikkan Kogyo Shimbun, Volume 45, No. 6 (May 2001) No.), p. 92-96

  Incidentally, as described above, the piezoelectric body formed on the elastic body by the aerosol deposition method usually needs to be fired at 500 ° C. to 700 ° C. in order to obtain good piezoelectric characteristics. This process is called a baking process. However, in the firing process, stress is generated in the piezoelectric body due to the difference in thermal expansion coefficient between the piezoelectric body and the elastic body, the piezoelectric characteristics of the piezoelectric body are reduced, cracks are generated, the piezoelectric body is peeled off from the elastic body, etc. As a result, there has been a problem that the characteristics of the vibration wave motor are deteriorated.

  Accordingly, an object of the present invention is to provide a vibration wave motor and a method of manufacturing the vibration wave motor that can suppress a decrease in the piezoelectric characteristics, cracks, or separation of the piezoelectric body necessary for exciting the elastic body. Is.

  The present invention includes an elastic body having a pair of surfaces including one surface and the other surface opposite to the one surface, and a plurality of convex portions formed on the one surface, and the elastic body A vibration wave motor that rotates the rotating body by vibration of the elastic body, the other surface of the elastic body, corresponding to the plurality of convex parts A piezoelectric body formed and fired by an aerosol deposition method, a plurality of electrodes disposed on the piezoelectric body and energizing the elastic body by application of an alternating voltage, and the elastic body The other surface is provided with a stress relaxation body that is provided with a gap between the piezoelectric body and that relieves stress applied to the piezoelectric body during firing.

  The present invention also includes an elastic body having a pair of surfaces including one surface and the other surface opposite to the one surface, and a plurality of convex portions formed on the one surface, and the elastic body. A rotating body opposed to the plurality of convex portions, and a method of manufacturing a vibration wave motor that rotates the rotating body by vibration of the elastic body. A first film forming step of forming a piezoelectric material by a aerosol deposition method at a position corresponding to the convex portion of the elastic body, and a gap with the piezoelectric material film on the other surface of the elastic body. A second film forming step for forming a stress relaxation body for relaxing stress applied to the piezoelectric body, and a raw material film for the piezoelectric body formed in the first film forming step together with the stress relaxation body. And a firing step of firing to form the piezoelectric body. Than is.

  According to the present invention, when the piezoelectric body is formed by firing, the stress applied to the piezoelectric body is relieved by the stress relaxation body due to the difference in thermal expansion coefficient between the elastic body and the piezoelectric body. Thereby, the fall of the piezoelectric characteristic of a piezoelectric material, a crack, and peeling can be suppressed. Even if cracks or peeling occurs in the stress relaxation body, since the stress relaxation body is provided with a gap from the piezoelectric body, the cracks and peeling of the stress relaxation body do not affect the piezoelectric body. Accordingly, it is possible to suppress a decrease in the performance of the vibration wave motor.

It is a schematic diagram of the film-forming apparatus which forms ceramics into a film by the aerosol deposition method. It is explanatory drawing of the vibration wave motor which concerns on 1st Embodiment of this invention, (a) is sectional drawing of a vibration wave motor, (b) is a perspective view of an elastic body. It is explanatory drawing explaining the manufacturing process of the vibrating body of the vibration wave motor which concerns on 1st Embodiment of this invention, (a) is the figure which formed the piezoelectric material and the stress relaxation body into a film in the elastic body, (b) is piezoelectric It is the figure which formed the electrode film on the body. It is explanatory drawing explaining the manufacturing process of the vibrating body of the vibration wave motor which concerns on 2nd Embodiment of this invention, (a) is the figure which formed the piezoelectric material and the stress relaxation body into a film in the elastic body, (b) is piezoelectric It is the figure which formed the electrode film on the body. It is explanatory drawing explaining the manufacturing process of the vibrating body of the vibration wave motor which concerns on 3rd Embodiment of this invention, (a) is the figure which formed the piezoelectric material and the stress relaxation body into the film in the elastic body, (b) is piezoelectric It is the figure which formed the electrode film on the body. It is explanatory drawing explaining the manufacturing process of the vibrating body of the conventional vibration wave motor, (a) is a figure of the elastic body before film-forming, (b) is the figure which formed the piezoelectric body into a film on the elastic body, (c) FIG. 4 is a diagram in which an electrode is formed on a piezoelectric body.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an explanatory diagram showing a schematic configuration of a film forming apparatus using an aerosol deposition method according to the first embodiment of the present invention. A film forming apparatus 1 shown in FIG. 1 includes a film forming unit 2 and an aerosol generating unit 3, and forms a ceramic film on a substrate by an aerosol deposition method. The aerosol generating unit 3 includes an aerosol generator 30 and a mass flow controller 32 that adjusts the amount of gas injected from the gas supply source 33 into the aerosol generator 30 by the gas transport pipe 31. The base end portion of the aerosol transport pipe 4 is inserted into the upper part of the aerosol generator 30. The aerosol generating unit 3 configured as described above disperses the ceramic fine particle powder in the gas to form an aerosol, and conveys the aerosol to the film forming unit 2 through the aerosol conveying tube 4. The film forming unit 2 has a vacuum chamber 20 that is evacuated (depressurized) by a vacuum pump 21, and sprays aerosol 6 onto the substrate 7 in a reduced-pressure atmosphere from a nozzle 5 disposed at the tip of the transfer tube 4. To form a film. The substrate 7 is fixed to the XY stage 8 and forms a film while moving the substrate 7 in the X-axis direction and the Y-axis direction.

  In the first embodiment, a piezoelectric raw material such as PZT (lead zirconate titanate) is used as the ceramic, and a metal elastic body of a vibration wave motor is installed as the substrate 7. By forming a piezoelectric material film by the aerosol deposition method, a piezoelectric film having a uniform composition of about 10 to 100 μm can be formed in one film forming process. Further, a mask 9 having a shape corresponding to the desired shape of the piezoelectric material to be formed on the substrate 7 is placed between the nozzle 5 and the substrate 7, thereby forming a film having a desired shape on the substrate 7. be able to.

  As shown in FIG. 2A, the vibration wave motor 50 includes a rotating body 60, a vibrating body 70 that rotates the rotating body 60 by vibration, a pressurizing mechanism 80 that presses the rotating body 60 against the vibrating body 70, It has.

  The vibrating body 70 has an elastic body 201 formed in an annular shape. The elastic body 201 has a pair of surfaces including one surface 201a and the other surface 201b opposite to the surface 201a. The vibrating body 70 is bonded and fixed to one surface 201 a of the elastic body 201, the sliding material 71 that contacts the rotating body 60, the piezoelectric body 202 formed on the other surface 201 b of the elastic body 201, and the piezoelectric body And a plurality of electrodes 203 formed on 202.

  The piezoelectric body 202 is an electro-mechanical energy conversion element, and converts input electric energy into vibration energy. The rotating body 60 contacts the sliding member 71, and the rotating body 60 is pressurized by the pressurizing mechanism 80. The pressurizing mechanism 80 includes a pressurizing spring 81 and a spring receiver 82, and the spring receiver 82 is fixed to the rotating shaft 90. The rotating body 60 and the pressing spring 81 are integrated with the rotating shaft 90 via the spring receiver 82. Rotate. The rotating body 60, the vibrating body 70 and the pressurizing mechanism 80 are covered with a housing 91. The housing 91 includes a base portion 92 and a case portion 94. A bearing 93 is attached to the base portion 92 of the housing 91, and a bearing 95 is attached to the case portion 94. The bearings 93 and 95 support the rotary shaft 90 in a freely rotatable manner. An insertion hole 92a through which the rotation shaft 90 is inserted is formed at the center of the base 92 of the housing 91, and an annular shape that protrudes inward of the housing around the insertion hole 92a and supports the vibrating body 70 (elastic body 201). The support portion 92b is formed.

  On one surface 201a of the elastic body 201, as shown in FIG. 2B, a plurality of convex portions 201c are formed. The plurality of convex portions 201c are arranged in an annular shape at equal intervals, and a groove 201d extending in the radial direction is formed between adjacent convex portions 201c. As shown in FIG. 2A, the rotating body 60 is disposed relative to the plurality of convex portions 201 c via the sliding material 71.

  A hole 201e through which the rotation shaft 90 is inserted is formed at the center of the elastic body 201, and a thin portion 201f having a thickness smaller than the convex portion 201c and the groove 201d is formed around the hole 201e. The thin portion 201f is formed in an annular shape. The elastic body 201 includes an annular inner peripheral part 201A and an annular outer peripheral part 201B formed outside the inner peripheral part 201A. The inner peripheral portion 201A is a thin portion 201f formed thinner than the outer peripheral portion 201B, and the outer peripheral portion 201B has a plurality of convex portions 201c and a plurality of grooves formed on one surface thereof along the circumferential direction. 201d is formed. The inner peripheral portion 201A is fixed to a support portion 92b formed on the base portion 92 of the housing 91 by press fitting or adhesion so that the outer peripheral portion 201B does not contact the housing 91. Since the inner peripheral portion 201A is formed to be thin, it prevents the outer peripheral portion 201B having the convex portion 201c and the groove 201d from being disturbed.

  A piezoelectric body 202 and a plurality of electrodes 203 are formed on the other surface 201 b of the elastic body 201. The piezoelectric body 202 is formed at a position corresponding to the plurality of convex portions 201c and the plurality of grooves 201d, and the length in the radial direction is set to be the same as the length in the radial direction of the plurality of convex portions 201c. It is formed into a shape. That is, the piezoelectric body 202 is formed on the outer peripheral portion 201B. The plurality of electrodes 203 are formed on the piezoelectric body 202. An AC voltage is applied to the electrode 203 and the elastic body 201 is excited. Thus, by forming the electrode 203 at a location corresponding to the convex portion 201c and the groove 201d, excitation of vibration is facilitated and rotation of the rotating body 60 is easily generated.

  By the way, the piezoelectric body 202 is a ceramic formed by an aerosol deposition method, and is fired at a temperature of 500 ° C. to 700 ° C. in order to improve the piezoelectric characteristics of the piezoelectric body 202. At this time, stress is generated in the piezoelectric body 202 due to a difference in thermal expansion coefficient between the piezoelectric body 202 and the elastic body 201. Specifically, since the elastic body 201 and the piezoelectric body 202 are formed in an annular shape, the elastic body 201 and the piezoelectric body 202 expand mainly in the radial direction during firing, but the difference in thermal expansion coefficient. As a result, a stress is generated in the radial direction in the piezoelectric body 202. Therefore, in the first embodiment, the stress relaxation body 204 is formed on the other surface 201b of the elastic body 201 with a gap from the piezoelectric body 202. The stress relaxation body 204 is formed on the inner peripheral portion 201 </ b> A of the elastic body 201.

  Since the stress relaxation body 204 exerts its effect in the firing process among the manufacturing processes for manufacturing the vibrating body 70, the manufacturing process of the vibrating body 70 will be described in detail with reference to FIG. This manufacturing process includes a film forming process, a baking process, and an electrode forming process.

  First, the film forming process will be described. As shown in FIG. 3A, PZT which is a raw material of the piezoelectric body 202 is formed on the other surface 201b of the elastic body 201 by an aerosol deposition method. At this time, the film is formed using the mask 9 of FIG. In the mask 9, openings corresponding to the shapes of the piezoelectric body 202 and the stress relaxation body 204 are formed. By forming a film using the mask 9, the other surface 201b of the elastic body 201 has The raw material film of the piezoelectric body 202 and the stress relaxation body 204 are formed simultaneously. In other words, the process of forming the raw material of the piezoelectric body 202 (first film forming process) and the process of forming the stress relaxation body 204 (second film forming process) are performed simultaneously. That is, the stress relaxation body 204 is formed by forming a film of the same raw material as that of the piezoelectric body 202 by the aerosol deposition method. In this way, by using the same raw material as the piezoelectric body 202 as the stress relaxation body 204, it is not necessary to provide a separate process for forming the stress relaxation body 204 separately, and the stress relaxation is performed simultaneously with the raw material film to be the piezoelectric body 202. The body 204 can be formed. Therefore, the productivity of the vibrating body 70, and hence the vibration wave motor 50, is improved. The piezoelectric body 202 and the stress relaxation body 204 are formed on the other surface 201b of the elastic body 201 with a thickness of about 10 to 100 μm. The raw material film of the piezoelectric body 202 and the stress relaxation body 204 are formed in an unconnected state on the other surface 201b of the elastic body 201 with a gap D1.

  Next, the formed raw material film to be the piezoelectric body 202 is fired together with the stress relaxation body 204 to form the piezoelectric body 202 (firing step). In this firing step, firing is performed at a temperature of 500 ° C. to 700 ° C. in order to improve the piezoelectric characteristics of the piezoelectric body 202.

  Next, a plurality of electrodes (electrode films) 203 shown in FIG. 3B are formed on the piezoelectric body 202 by sputtering or printing (electrode forming step). After this step, a polarization process is performed. The vibrating body 70 is manufactured by the above process. Here, one piezoelectric element is formed by one electrode 203 and the 202 portion of the piezoelectric body facing the electrode 203, and the piezoelectric elements are formed by the number of electrodes 203 shown in FIG.

  The plurality of electrodes 203 are configured to be divided into a first electrode group 203a arranged in a ring shape and a second electrode group 203b arranged in a ring shape inside the first electrode group 203a. That is, the plurality of piezoelectric elements are divided into a first piezoelectric element group arranged in an annular shape and a second piezoelectric element group arranged in an annular shape inside the first piezoelectric element group. Each piezoelectric element in each piezoelectric element group is formed by reversing the polarization direction for each element. Then, AC voltages having different phases are applied to the electrode groups 203a and 203b. As a result, two standing wave vibrations are excited, the two standing wave vibrations are combined into a traveling wave, and the surface 201a of the elastic body 201 moves elliptically. A rotating motion is imparted to the rotating body 60 that is in pressure contact with the convex portion 201 c of the elastic body 201 via the sliding member 71 by the flexural vibration of the elastic body 201.

  Here, the piezoelectric body 202 is formed by the firing operation in the firing step. During this firing, the piezoelectric body 202 is formed due to the difference in thermal expansion coefficient between the ceramic piezoelectric body 202 and the metal elastic body 201. The generated stress is relaxed by the stress relaxation body 204. In other words, stress is applied to the piezoelectric body 202 in the radial direction due to thermal expansion of the elastic body 201, but stress is also applied to the stress relaxation body 204 in the radial direction. As described above, since stress is dispersed by acting on both the piezoelectric body 202 and the stress relaxation body 204, the stress is prevented from concentrating on the piezoelectric body 202. Since the stress relaxing body 204 relieves the stress acting on the piezoelectric body 202 during firing, the piezoelectric characteristics of the piezoelectric body 202 can be prevented from being deteriorated. In addition, the occurrence of cracks in the piezoelectric body 202 can be suppressed, and peeling of the piezoelectric body 202 can be suppressed. Therefore, the manufacturing yield of the vibrating body 70, and hence the vibration wave motor 50, can be improved.

  Further, by using the stress relaxation body 204 as the same raw material as the piezoelectric body 202, the thermal expansion coefficient of the stress relaxation body 204 and the thermal expansion coefficient of the piezoelectric body 202 can be made equal. Therefore, it is possible to effectively suppress the concentration of stress on the stress relaxation body 204. In addition, the influence of the difference in thermal expansion coefficient exerted on the piezoelectric body 202 by the stress relaxation body 204 can be reduced.

  In this firing step, the stress relaxation body 204 has no particular problem even if cracks are generated or peeled off or the piezoelectric characteristics are lowered. That is, since the stress relaxation body 204 is formed with a gap D1 from the piezoelectric body 202, it is not formed continuously with the piezoelectric body 202, and cracks and peeling occur in the stress relaxation body 204. However, the piezoelectric body 202 is not affected by cracks or peeling of the stress relaxation body 204. That is, no cracks or peeling occurs in the piezoelectric body 202 due to cracks or peeling of the stress relaxation body 204. Therefore, it is possible to suppress a decrease in the performance of the vibration wave motor 50.

[Second Embodiment]
Next, the vibration wave motor according to the second embodiment will be described with reference to the drawings showing the manufacturing process of the vibrating body 70A shown in FIG. Note that in the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Since the elastic body 201 is formed in an annular shape, the elastic body 201 expands in the radial direction in the firing step. Therefore, stress acts on the piezoelectric body 202A in the radial direction. Therefore, in the film forming step (first film forming step), as shown in FIG. 4A, the piezoelectric body 202A is formed by being divided in the radial direction. In the second embodiment, as shown in FIG. 4B, the piezoelectric body 202A is divided into a portion (divided piece) 202a corresponding to the first electrode group 203a and a portion (divided piece) corresponding to the second electrode group 203b. ) 202b. Here, the divided pieces 202a and the divided pieces 202b are formed by being divided by the mask 9 (FIG. 1). Therefore, a step of dividing after film formation is not necessary. A gap D2 is provided between the divided piece 202a and the divided piece 202b thus formed. Even if the piezoelectric body 202A is divided into the divided pieces 202a and 202b, the influence on the excitation of the vibration of the elastic body 201 is small. A firing process is performed after the piezoelectric body 202A is formed by an aerosol deposition method, and then an electrode forming process is performed in which the electrode 203 is formed.

  As described above, in the second embodiment, the stress relaxation body 204 is provided in the same manner as in the first embodiment, so that the reduction in the piezoelectric characteristics of the piezoelectric body 202A is suppressed, and the generation and separation of cracks in the piezoelectric body 202A are suppressed. The same effect as the first embodiment is achieved. Furthermore, in the second embodiment, by dividing the piezoelectric body 202A in the radial direction, it is possible to reduce the stress generated in each of the divided pieces 202a and 202b in the firing process. Thereby, generation | occurrence | production of the crack of piezoelectric body 202A, peeling, and the fall of a piezoelectric characteristic can be suppressed more effectively. Therefore, it is possible to improve the manufacturing yield of the vibrating body 70A and thus the vibration wave motor.

  Further, since the piezoelectric body 202A is divided into the divided pieces 202a and 202b corresponding to the respective electrode groups 203a and 203b, the vibration of the elastic body 201 by the piezoelectric body 202A is more than that in the case where the piezoelectric body is integrally formed. The damping action can be reduced. Therefore, the elastic body 201 can be vibrated more effectively.

[Third Embodiment]
Next, the vibration wave motor according to the third embodiment will be described with reference to the drawings showing the manufacturing process of the vibrating body 70B shown in FIG. Note that in the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the film formation process of the piezoelectric body 202B, as shown in FIG. 5A, the piezoelectric body 202B is divided in the radial direction and divided in the circumferential direction. Then, after the firing process, in the electrode forming process, as shown in FIG. 5B, one electrode 203 is formed on each divided piece 202c. In other words, the piezoelectric body 202B is divided for each electrode. Each divided piece 202c is divided into films by the mask 9 (FIG. 1) in the film forming process. Therefore, a step of dividing after film formation is not necessary. Gaps D2 and D3 are provided between the divided pieces 202c formed in this way. Even if the piezoelectric body 202 is divided into the divided pieces 202 c for each electrode 203, the influence on the excitation of vibration of the elastic body 201 is small.

  As described above, in the third embodiment, the stress relaxation body 204 is provided in the same manner as in the first embodiment, so that the reduction of the piezoelectric characteristics of the piezoelectric body 202B is suppressed, and the occurrence of cracks and peeling of the piezoelectric body 202B are suppressed. The same effect as the first embodiment is achieved. Furthermore, in the third embodiment, since the piezoelectric body 202B is divided and formed for each electrode 203, the piezoelectric body is further finely divided than in the second embodiment, so that the piezoelectric body 202B is more effectively produced. Generation of cracks, peeling, and deterioration of piezoelectric characteristics can be suppressed. Therefore, it is possible to improve the manufacturing yield of the vibrating body 70B, and hence the vibration wave motor.

  In the third embodiment, since the piezoelectric body 202B is divided for each electrode 203, the vibration damping action of the elastic body 201 by the piezoelectric body 202B is more effective than when the piezoelectric body 202B is integrally formed. Can be reduced. Therefore, the elastic body 201 can be vibrated more effectively.

  In addition, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. In the above-described embodiment, the case where the stress relaxation body is formed of the same material as the piezoelectric body has been described. However, the present invention is not limited to this, and any other ceramic material may be used as long as the material can relieve stress. The film may be formed. In this case, the stress relaxation body may be formed by the aerosol deposition method. Further, as long as the material can relieve stress, the film may be formed of a material other than the ceramic material. In any case, it is preferable that the thermal expansion coefficient is the same as or close to that of the piezoelectric body.

  Moreover, in the said embodiment, the 1st film-forming process which forms the raw material of a piezoelectric material and the 2nd film-forming process which forms a stress relaxation body are simultaneously performed by one film-forming process (one process). Although the case has been described, the present invention is not limited to this, and each step may be performed separately.

  Moreover, although the said embodiment demonstrated the case where a stress relaxation body was formed in the annular shape inside a piezoelectric material, it is not limited to this. When the elastic body has an inner peripheral portion having a convex portion and an outer peripheral portion formed outside the inner peripheral portion, a stress relaxation body may be provided on the outer peripheral portion. In this case, the stress relaxation body is preferably formed in a ring shape.

  Moreover, although the said embodiment demonstrated the case where an elastic body was a ring shape, it is not limited to a circle, It is possible to apply to all ring shapes, such as a polygon. Further, in the above embodiment, the case where the piezoelectric body and the stress relaxation body are formed in a non-connected state has been described. However, the piezoelectric body and the stress relaxation body have a thin coupling portion that does not affect stress relaxation. And may be linked.

50 Vibration wave motor 60 Rotating body 201 Elastic body 201c Convex parts 202, 202A, 202B Piezoelectric body 203 Electrode 204 Stress relaxation body

Claims (7)

An elastic body having a pair of surfaces composed of one surface and the other surface opposite to the one surface, and a plurality of convex portions formed on the one surface, and the plurality of convex portions of the elastic body A vibration wave motor that rotates the rotating body by vibration of the elastic body.
A piezoelectric body formed on the other surface of the elastic body by an aerosol deposition method at a position corresponding to the plurality of convex portions, and fired;
A plurality of electrodes disposed on the piezoelectric body and exciting the elastic body by application of an alternating voltage;
A vibration wave motor comprising: a stress relaxation body that is provided on the other surface of the elastic body with a gap between the piezoelectric body and that relieves stress applied to the piezoelectric body during firing. .   The vibration wave motor according to claim 1, wherein the stress relaxation body is formed by forming the same raw material as the piezoelectric body by an aerosol deposition method. The plurality of convex portions are arranged in an annular shape,
The vibration wave motor according to claim 1, wherein the piezoelectric body is formed in an annular shape corresponding to the plurality of convex portions. The plurality of electrodes include a first electrode group arranged in an annular shape, and a second electrode group arranged in an annular shape inside the first electrode group,
4. The vibration according to claim 3, wherein the piezoelectric body is formed by dividing in a radial direction a portion corresponding to the first electrode group and a portion corresponding to the second electrode group. Wave motor.   5. The vibration wave motor according to claim 1, wherein the piezoelectric body is divided for each of the electrodes. An elastic body having a pair of surfaces composed of one surface and the other surface opposite to the one surface, and a plurality of convex portions formed on the one surface, and the plurality of convex portions of the elastic body A rotating wave motor, wherein the rotating body is rotated by the vibration of the elastic body.
A first film forming step of forming a raw material of the piezoelectric body by an aerosol deposition method on the other surface of the elastic body and corresponding to the plurality of convex portions;
A second film forming step of forming a stress relaxation body that relaxes the stress applied to the piezoelectric body by forming a gap with the raw material film of the piezoelectric body on the other surface of the elastic body;
A firing step of firing the piezoelectric material film formed in the first film formation step together with the stress relaxation body to form the piezoelectric body. Production method.   7. The film formation using the same raw material in the first film formation process and the second film formation process using a mask corresponding to the shape of the piezoelectric body and the stress relaxation body. The manufacturing method of the vibration wave motor of description.

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