Rotor, stator, and ultrasonic motor

Abstract

Provided is a rotor capable of suppressing sticking.　A rotor 4 according to the present invention is used in an ultrasonic motor 1 comprising a stator 2 that has a vibrator 3 and a vibration generating element (piezoelectric element 13) provided on the vibrator 3, the rotor comprising: a rotor body 4A, and a sliding material 7 provided on the rotor body 4A and in contact with the vibrator 3. The sliding material 7 is made of carbon graphite.

Description

Technical Field

[0001] The present invention relates to a rotor, a stator, and an ultrasonic motor.

Background Art

[0002] Conventionally, various ultrasonic motors have been proposed that vibrate a stator using a piezoelectric element. Patent Document 1 below discloses an example of an ultrasonic motor. In this ultrasonic motor, a rotor is rotated by a progressive vibration wave generated in the stator.

[0003] The stator in Patent Document 1 is formed by adhering a ring-shaped piezoelectric body to a ring-shaped elastic body. A progressive vibration wave is generated in the elastic body due to the vibration of the piezoelectric body. On the other hand, the rotor is formed by adhering a ring-shaped slider material to a ring-shaped rotor base material. The slider material in the rotor is in contact with the elastic body in the stator. When the rotor rotates, the slider material slides on the surface of the elastic body. The slider material in Patent Document 1 is made of resin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When an ultrasonic motor using a slider material made of resin is used in an environment with high humidity, etc., the rotor may stick to the stator, the stator and the rotor may be fixed to each other, and the ultrasonic motor may not be able to start. This phenomenon is called "adhesion".

[0006] When a slider material made of resin slides across the surface of the stator, wear particles, which are finely crushed by mechanical friction, and low-molecular-weight components, which are decomposed by frictional heat, are generated from the slider material. The inventors have found that the low-molecular-weight components generated from the slider material include water-soluble components. The inventors have found that when the water-soluble components, or a mixture of water-soluble components and wear particles, are exposed to moisture and then dried, they exhibit adhesive properties, allowing the stator and rotor to be fixed to each other. This can result in adhesion.

[0007] If seizing occurs, the ultrasonic motor cannot be started even if a drive signal is applied. Therefore, seizing results in a fatal failure of the ultrasonic motor.

[0008] The object of the present invention is to provide a rotor, stator, and ultrasonic motor that can suppress sticking. [Means for solving the problem]

[0009] The rotor according to the present invention is a rotor used in an ultrasonic motor having a stator having a vibrating body and a vibration generating element provided on the vibrating body, and comprises a rotor body and a sliding material provided on the rotor body and in contact with the vibrating body, wherein the sliding material is made of carbon graphite.

[0010] The stator according to the present invention is a stator used in an ultrasonic motor equipped with a rotor, comprising a vibrating body, a vibration generating element provided on the vibrating body, and a sliding material provided on the vibrating body and in contact with the rotor, wherein the sliding material is made of carbon graphite.

[0011] In a broad aspect of the ultrasonic motor according to the present invention, the ultrasonic motor comprises a rotor configured according to the present invention, a vibrating body, and a stator having the vibration generating element provided on the vibrating body.

[0012] In other broad aspects of the ultrasonic motor according to the present invention, the device comprises a stator and a rotor configured according to the present invention. [Effects of the Invention]

[0013] According to the rotor, stator, and ultrasonic motor of the present invention, sticking can be suppressed. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic front cross-sectional view of an ultrasonic motor according to a first embodiment of the present invention. [Figure 2] Figure 2 is a schematic plan view of the stator in the first embodiment of the present invention. [Figure 3] Figure 3 is a schematic plan view of the rotor in the first embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view along line II in Figure 3. [Figure 5] Figure 5 is a schematic front cross-sectional view of a piezoelectric element in a first embodiment of the present invention. [Figure 6] Figure 6 is a schematic plan view of a rotor according to a second embodiment of the present invention. [Figure 7] Figure 7 is a schematic plan view of a rotor according to a third embodiment of the present invention. [Figure 8] Figure 8 is a schematic plan view of a rotor according to a modified example of the third embodiment of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view of a rotor according to a fourth embodiment of the present invention, showing a portion corresponding to the cross-section along line II in Figure 3. [Figure 10] Figure 10 is a schematic cross-sectional view showing a state in which the portion of the rotor shown in Figure 9 according to the fourth embodiment of the present invention is in contact with the vibrating element of the stator, and a traveling wave is generated in the stator. [Figure 11] Figure 11 is a schematic cross-sectional view of a rotor according to a modified example of the fourth embodiment of the present invention, showing a portion corresponding to the cross-section along line II in Figure 3. [Figure 12] FIG. 12 is a schematic bottom view of a stator according to a fifth embodiment of the present invention. [Figure 13] FIG. 13 is a schematic bottom view of a stator according to a sixth embodiment of the present invention. [Figure 14] FIG. 14 is a schematic cross-sectional view taken along line II-II in FIG. 13.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention while referring to the drawings.

[0016] It should be noted that each embodiment described in this specification is exemplary, and it is pointed out that partial substitution or combination of configurations is possible between different embodiments.

[0017] FIG. 1 is a schematic front cross-sectional view of an ultrasonic motor according to a first embodiment of the present invention.

[0018] The ultrasonic motor 1 has a stator 2, a rotor 4, and a shaft member 10. The stator 2 and the rotor 4 are in contact with each other. The rotor 4 is a rotor according to an embodiment of the present invention. The rotor 4 rotates due to the traveling wave generated in the stator 2. As the rotor 4 rotates, the shaft member 10 rotates. The rotation center axis of the ultrasonic motor 1 is located at the portion where the shaft member 10 is provided. Hereinafter, the specific configuration of the ultrasonic motor 1 will be described.

[0019] FIG. 2 is a schematic plan view of the stator in the first embodiment.

[0020] The stator 2 has a plate-shaped vibrating body 3. The vibrating body 3 has a disk shape. The vibrating body 3 has a first main surface 3a and a second main surface 3b. The first main surface 3a and the second main surface 3b face each other.

[0021] A through-hole 3c is provided in the center of the vibrating body 3. As shown in Figure 1, the shaft member 10 is inserted through the through-hole 3c. Note that the position of the through-hole 3c is not limited to the center of the vibrating body 3. The through-hole 3c only needs to be located in the region that includes the rotational axis. Furthermore, the shape of the vibrating body 3 is not limited to a disc shape.

[0022] In this specification, the axial direction Z refers to the direction connecting the first principal surface 3a and the second principal surface 3b, and is aligned with the rotational axis. In this embodiment, the axial direction Z is parallel to the direction in which the shaft member 10 extends. The shape of the vibrating body 3 as viewed from the axial direction Z may be a regular polygon such as a regular hexagon, regular octagon, or regular decagon. In this specification, the term polygon includes cases where the vertices are curved and cases where the vertices are chamfered. Hereafter, viewing from the axial direction Z may be referred to as a plan view.

[0023] The vibrating body 3 is made of a suitable metal. However, the vibrating body 3 does not necessarily have to be made of metal. The vibrating body 3 may be made of other elastic materials, such as ceramics or silicon.

[0024] As shown in Figure 2, a plurality of piezoelectric elements 13 are provided on the first main surface 3a of the vibrating body 3. The piezoelectric elements 13 are vibration generating elements in the present invention. In a plan view, the plurality of piezoelectric elements 13 are dispersed in the circumferential direction. More specifically, the plurality of piezoelectric elements 13 are dispersed along the circumferential direction of the traveling wave so as to generate a traveling wave that circulates around an axis parallel to the axial direction Z. A structure in which a stator 2 generates a traveling wave by dispersing and driving a plurality of piezoelectric elements 13 in the circumferential direction is disclosed, for example, in International Publication No. 2010 / 061508. Therefore, a detailed explanation of the generation of the traveling wave will be omitted.

[0025] Figure 3 is a schematic plan view of the rotor in the first embodiment.

[0026] The rotor 4 comprises a rotor body 4A and a sliding material 7. The rotor body 4A has an annular shape in plan view. A through hole 4c is provided in the center of the rotor body 4A. The shaft member 10 shown in Figure 1 is inserted through the through hole 4c. However, the position of the through hole 4c is not limited to the center of the rotor body 4A. The through hole 4c only needs to be located in a region that includes the rotational axis. Furthermore, the shape of the rotor body 4A is not limited to the above. The outer shape of the rotor body 4A in plan view may be a regular polygon such as a regular hexagon, regular octagon, or regular decagon.

[0027] The sliding material 7 is provided on the rotor body 4A. In plan view, the sliding material 7 has an annular shape. The sliding material 7 is provided so as to surround the through hole 4c of the rotor body 4A. The sliding material 7 is a component that contacts the stator 2 shown in Figure 1. In this embodiment, specifically, it contacts the vibrating body 3 in the stator 2. When the ultrasonic motor 1 is driven and the rotor 4 is rotated, the sliding material 7 on the rotor 4 slides against the surface of the vibrating body 3 in the stator 2.

[0028] The sliding material 7 is made of carbon-graphite. Carbon-graphite refers to a carbon-based material whose degree of graphitization R = D / G is 0.5 or greater and 1.2 or less. More specifically, in the Raman spectrum of carbon-graphite obtained by Raman spectroscopy, the peak value of the D band is D. In the same Raman spectrum, the peak value of the G band is G. Note that the D band is at 1360 cm⁻¹ in the Raman spectrum. -1 This is the frequency band in the vicinity. The G band corresponds to 1580 cm⁻¹ in the Raman spectrum. -1 This is the surrounding frequency band. The degree of graphitization R of carbon-graphite is the value obtained by dividing the peak value D by the peak value G.

[0029] In calculating the degree of graphitization R in this specification, a Raman spectrum of the carbon-graphite material used in the sliding material is obtained by Raman spectroscopy with an incident laser wavelength of 532 nm and a grating type of 600 gr / m. Next, the peak values ​​D and G in the obtained Raman spectrum are determined. Then, using the determined peak values ​​D and G, R = D / G is calculated.

[0030] Furthermore, it is preferable to smooth the Raman spectrum using a Savizky-Golay-2nd filter before determining the peak values ​​D and G.

[0031] If the degree of graphitization R of the carbon-graphite material constituting the sliding material 7 is too high, the lubricity of the sliding material 7 may decrease. On the other hand, if the degree of graphitization R of the carbon-graphite material constituting the sliding material 7 is too low, the wear resistance of the sliding material 7 may decrease.

[0032] To obtain the carbon-graphite material that constitutes the sliding material 7, a carbon solid is obtained, for example, by compressing carbon powder. Subsequently, the carbon solid is subjected to heat treatment to promote the crystallization of a portion of the carbon solid. In other words, a portion of the carbon solid is converted from carbonaceous to graphite. This yields carbon-graphite. However, carbon-graphite is a material obtained by promoting the crystallization of a portion of the carbon solid, and carbon-graphite is a type of amorphous carbon.

[0033] As shown in Figure 3, the rotor body 4A has a rotor base portion 5 and a leaf spring portion 6. The outer shape of the rotor body 4A in plan view is the same as the outer shape of the rotor base portion 5 in plan view. The through hole 4c of the rotor body 4A is provided in the rotor base portion 5. On the other hand, the shape of the leaf spring portion 6 in plan view is an annular shape. The leaf spring portion 6 is provided so as to surround the through hole 4c. The material of the rotor base portion 5 can be any suitable metal or suitable ceramics. The material of the leaf spring portion 6 can be any suitable metal or the like.

[0034] Figure 4 is a schematic cross-sectional view along line II in Figure 3. The dashed line in Figure 4 schematically shows the displacement of the leaf spring section, which will be described later.

[0035] The rotor base portion 5 has a recess 5a. Although not shown in the figure, the shape of the recess 5a in plan view is annular. A leaf spring portion 6 is provided on the rotor base portion 5 so as to cover the recess 5a. The leaf spring portion 6 has a first surface 6a and a second surface 6b. The first surface 6a and the second surface 6b face each other. Of the first surface 6a and the second surface 6b, the first surface 6a is located on the stator 2 side as shown in Figure 1.

[0036] The sliding material 7 is provided on the leaf spring portion 6 of the rotor body 4A. In this specification, when one member is provided on another member, this includes cases where one member is directly provided on another member, and cases where one member is indirectly provided on another member via another layer or the like. In this embodiment, the sliding material 7 is directly provided on the leaf spring portion 6. The sliding material 7 may be joined to the leaf spring portion 6 by a bonding member such as an adhesive.

[0037] All parts of the sliding material 7 overlap with the recess 5a of the rotor base portion 5 in a plan view. The width of the sliding material 7 is narrower than the width of the leaf spring portion 6 and the width of the recess 5a. In this embodiment, the width of the sliding material 7 is the distance between the inner and outer edges of the sliding material 7 when viewed in a plan view. The same applies to the width of the leaf spring portion 6 and the width of the recess 5a.

[0038] Returning to Figure 3, a key feature of this embodiment is that a sliding material 7 is provided on the rotor body 4A of the rotor 4, and the sliding material 7 is made of carbon graphite. This makes it possible to suppress sticking even when the ultrasonic motor 1 using the rotor 4 is used in environments with high humidity. Sticking refers to the phenomenon in which the rotor sticks to the stator, fixing the stator and rotor together, and preventing the ultrasonic motor from starting. The details of the above effect will be explained below.

[0039] When the ultrasonic motor 1 shown in Figure 1 is driven, the sliding material 7 on the rotor 4 slides against the surface of the vibrating body 3 on the stator 2. Even if wear particles are generated from the sliding material 7, which is made of carbon graphite, no water-soluble components that would function as an adhesive are produced. Therefore, even in environments with high humidity where the rotor 4 and stator 2 are exposed to moisture, solidification is unlikely to occur at the contact points between the rotor 4 and stator 2 in the ultrasonic motor 1. This suppresses sticking. As a result, the ultrasonic motor 1 can be used suitably even in harsh environments with high humidity.

[0040] As shown in Figure 4, it is preferable that the rotor base portion 5 has a recess 5a, and that a leaf spring portion 6 is provided on the rotor base portion 5 so as to cover the recess 5a. Furthermore, it is preferable that a sliding material 7 is provided on the leaf spring portion 6. This allows the rotor 4 to rotate efficiently. This will be explained below.

[0041] In the stator 2 shown in Figure 1, the vibration of the piezoelectric element 13, which acts as a vibration generating element, causes the vibrating body 3 to be displaced, generating a traveling wave. When a traveling wave is generated, parts of the vibrating body 3 are displaced greatly, and parts are displaced less greatly. More specifically, when a traveling wave is generated, the displacement is greatest at the wave crest of the traveling wave in the vibrating body 3. The displacement is also large in the parts of the vibrating body 3 surrounding the wave crest. If the contact area between the greatly displaced parts of the vibrating body 3 and the rotor 4 is large, the rotor 4 can be rotated efficiently.

[0042] In this embodiment, as shown in Figure 4, a sliding material 7 is provided on the leaf spring portion 6. Therefore, the leaf spring portion 6 elastically deforms as shown by the dashed line in Figure 4, following the displacement of the vibrating body 3 due to the traveling wave. This allows the wave crest portion and the surrounding portion of the vibrating body 3 to come into contact with the sliding material 7 when a traveling wave is generated. Thus, the contact area between the portion of the vibrating body 3 that undergoes large displacement and the sliding material 7 on the rotor 4 can be increased. Consequently, the frictional force between the vibrating body 3 and the rotor 4 can be increased, and the rotor 4 can be rotated efficiently.

[0043] The configuration in which the rotor base portion 5 has a recess 5a and the leaf spring portion 6 is provided on the rotor base portion 5 so as to cover the recess 5a can also be applied to configurations of the present invention other than this embodiment. However, in the present invention, the rotor body 4A does not necessarily have to have the leaf spring portion 6. The rotor base portion 5 does not necessarily have to have a recess 5a. The sliding material 7 only needs to be provided on the rotor body 4A so as to contact the stator 2.

[0044] The configuration of this embodiment will be described in more detail below.

[0045] As shown in Figure 1, the ultrasonic motor 1 has a first case member 8 and a second case member 9. The second case member 9 is cap-shaped, and the first case member 8 is lid-shaped. The first case member 8 and the second case member 9 constitute the case. A spring member 16, a rotor 4, and a stator 2 are arranged inside the case.

[0046] The first case member 8 has a first cylindrical projection 8a and a second cylindrical projection 8b. The first cylindrical projection 8a protrudes outward from the case. The second cylindrical projection 8b protrudes inward from the case. A portion of the second cylindrical projection 8b is located within the through hole 3c of the vibrating body 3 of the stator 2.

[0047] A through hole 8c is continuously provided in the first cylindrical projection 8a and the second cylindrical projection 8b. A first bearing portion 18 is provided in the portion of the through hole 8c located in the first cylindrical projection 8a. The shaft member 10 is inserted through the through hole 8c and the first bearing portion 18. The shaft member 10 protrudes outward from the through hole 8c of the first case member 8. Note that the configuration of the first case member 8 is not limited to the above.

[0048] The second case member 9 has a cylindrical projection 9a. The cylindrical projection 9a protrudes to the outside of the case. A through hole 9c is provided in the cylindrical projection 9a. A second bearing portion 19 is provided in the through hole 9c. The shaft member 10 is inserted through the through hole 9c and the second bearing portion 19. The shaft member 10 protrudes to the outside of the case from the through hole 9c of the second case member 9. Note that the configuration of the second case member 9 is not limited to the above. For example, a sliding bearing or a bearing may be used for the first bearing portion 18 and the second bearing portion 19.

[0049] The sliding material 7 of the rotor 4 is in contact with the second main surface 3b of the vibrating body 3 in the stator 2. The second main surface 3b includes a contact surface 3d. The contact surface 3d is the portion of the second main surface 3b that is in contact with the rotor 4. The contact surface 3d is planar. More specifically, the contact surface 3d does not have any uneven structure. The contact surface 3d is configured in the same way as the other parts of the second main surface 3b. Therefore, in obtaining the stator 2 of this embodiment, it is not necessary to cut the second main surface 3b of the vibrating body 3. Thus, the productivity of the ultrasonic motor 1 can be increased.

[0050] An elastic member 12 is provided on the rotor base portion 5 of the rotor 4. More specifically, the elastic member 12 sandwiches the rotor 4 together with the stator 2 in the axial direction Z. The elastic member 12 has an annular shape. However, the shape of the elastic member 12 is not limited to the above. As the material of the elastic member 12, for example, rubber or resin can be used. However, the elastic member 12 is not required to be provided.

[0051] A spring member 16 is positioned on the second bearing portion 19 side of the elastic member 12. More specifically, the spring member 16 in this embodiment is a metal leaf spring. A through hole 16c is provided in the center of the spring member 16. The shaft member 10 is inserted through the through hole 16c. The shaft member 10 has a wide portion 10a. The width of the wide portion 10a of the shaft member 10 is wider than the width of other parts of the shaft member 10. The width of the shaft member 10 is a dimension along the direction perpendicular to the axial direction Z of the shaft member 10. The inner circumferential edge of the spring member 16 abuts against the wide portion 10a. This suppresses misalignment between the spring member 16 and the shaft member 10. However, the material and configuration of the spring member 16 are not limited to the above. The configuration of the shaft member 10 is also not limited to the above.

[0052] An elastic force is applied to the rotor 4 from the spring member 16 via the elastic member 12. This causes the rotor 4 to press against the stator 2. In this case, the frictional force between the stator 2 and the rotor 4 can be increased. Therefore, the traveling wave can be effectively propagated from the stator 2 to the rotor 4, and the rotor 4 can be rotated efficiently. Consequently, the ultrasonic motor 1 can be driven more reliably and efficiently.

[0053] As shown in Figure 1, a retaining ring 17 is provided on the shaft member 10. The retaining ring 17 has an annular shape. In plan view, the retaining ring 17 surrounds the shaft member 10. More specifically, the inner circumferential edge of the retaining ring 17 is located inside the shaft member 10. The retaining ring 17 abuts against the first bearing portion 18 from the outside in the axial direction Z. This defines the length between the retaining ring 17 and the wide portion 10a of the shaft member 10, and determines the amount of deflection of the spring member 16. As a result, the elastic force of the spring member 16 can be applied to the rotor 4 as described above. For example, metal or resin can be used as the material for the shaft member 10 and the retaining ring 17.

[0054] As shown in Figure 2, the stator 2 has a plurality of piezoelectric elements 13. The specific configuration of the piezoelectric elements 13 is described below.

[0055] Figure 5 is a schematic front cross-sectional view of the piezoelectric element in the first embodiment.

[0056] The piezoelectric element 13 has a piezoelectric body 14. The piezoelectric body 14 has a third main surface 14a and a fourth main surface 14b. The third main surface 14a and the fourth main surface 14b face each other. The piezoelectric element 13 has a first electrode 15A and a second electrode 15B. The first electrode 15A is provided on the third main surface 14a of the piezoelectric body 14, and the second electrode 15B is provided on the fourth main surface 14b. The shape of the piezoelectric element 13 in plan view is rectangular. However, the shape of the piezoelectric element 13 in plan view is not limited to the above, and may be, for example, elliptical.

[0057] In this embodiment, the stator 2 has four piezoelectric elements 13. However, the number of piezoelectric elements 13 is not limited to the above. The multiple piezoelectric elements 13 can be distributed along the direction of rotation of the traveling wave so as to generate a traveling wave that revolves around an axis parallel to the axial direction Z.

[0058] Alternatively, the stator 2 may have a single piezoelectric element divided into multiple regions. In this case, for example, each region of the piezoelectric element may be polarized in different directions. The shape of the piezoelectric element in plan view may be, for example, an annular shape.

[0059] Here, the first electrode 15A shown in Figure 5 is attached to the first main surface 3a of the vibrating body 3 with adhesive. The thickness of this adhesive is very thin. Therefore, the first electrode 15A is electrically connected to the vibrating body 3.

[0060] As shown in Figure 4, the rotor base portion 5 is provided with a groove 5b that connects to the inner circumferential edge of the recess 5a. Similarly, the rotor base portion 5 is provided with a groove 5c that connects to the outer circumferential edge of the recess 5a. The shapes of the grooves 5b and 5c in plan view are both annular. A leaf spring portion 6 is provided extending from groove 5b to groove 5c. More specifically, the inner circumferential edge of the leaf spring portion 6 is located within groove 5b. The outer circumferential edge of the leaf spring portion 6 is located within groove 5c.

[0061] In this case, with the thickness of the leaf spring portion 6 set to the desired thickness, the thickness of the portion of the leaf spring portion 6 that protrudes from the rotor base portion 5 in the axial direction Z can be reduced. Alternatively, if the dimensions corresponding to the depth of the grooves 5b and 5c are greater than or equal to the dimensions corresponding to the thickness of the leaf spring portion 6, the leaf spring portion 6 can be configured not to protrude from the rotor base portion 5 in the axial direction Z. This makes it difficult for the leaf spring portion 6 to detach from the rotor base portion 5.

[0062] In this embodiment, the rotor base portion 5 having grooves 5b and 5c and the leaf spring portion 6 are fitted together. In this case, the positioning of the leaf spring portion 6 is easier when forming the rotor 4. Therefore, the rotor 4 can be obtained efficiently, and the productivity of the ultrasonic motor 1 can be effectively increased. Note that grooves 5b and 5c are not necessarily required.

[0063] The ultrasonic motor 1 shown in Figure 1 is an example, and the configuration of the ultrasonic motor 1 is not limited to the above. Similarly, the configuration of the stator 2 is not limited to the above. The stator 2 only needs to have a suitable vibrating body 3 and a vibration generating element provided on the vibrating body 3. In the rotor 4 according to the present invention, the sliding material 7 should be provided so as to be in contact with the vibrating body 3 of the stator 2.

[0064] Figure 6 is a schematic plan view of a rotor according to a second embodiment of the present invention. In Figure 6, the dotted line indicates an annular trajectory A.

[0065] The rotor 24 of this embodiment differs from the rotor 4 of the first embodiment in that it has a plurality of sliding members 27. The plurality of sliding members 27 are distributed in an annular track A in a plan view. Apart from the above, the rotor 24 of this embodiment has the same configuration as the rotor 4 of the first embodiment.

[0066] In this embodiment, the annular trajectory A is a circular trajectory. The annular trajectory A corresponds to the trajectory along the circumferential direction of the traveling wave generated in the stator used with the rotor 24 in an ultrasonic motor. Therefore, the multiple sliding materials 27 are dispersed along the circumferential direction of the traveling wave.

[0067] The arrangement of multiple sliding materials 27 in the manner described above reduces the rigidity of the rotor 24 in the circumferential direction of the traveling wave. This makes it easier to effectively follow the displacement of the vibrating body of the stator when a traveling wave is generated in the stator used with the rotor 24. This allows for more reliable contact between the wave crest and surrounding areas of the vibrating body and the sliding material 27 when a traveling wave is generated. Consequently, the contact area between the highly displaced parts of the vibrating body and the sliding material 27 in the rotor 24 can be increased. Therefore, the frictional force between the vibrating body and the rotor 24 can be increased, allowing the rotor 24 to rotate more reliably and efficiently.

[0068] In addition, the multiple sliding materials 27 are made of carbon graphite. As a result, in this embodiment as well, sticking can be suppressed.

[0069] It is preferable that each sliding material 27 is positioned such that its center of gravity is located on the annular track A. This allows the ultrasonic motor to be driven more reliably and stably when the rotor 24 is used in an ultrasonic motor. It is sufficient that any part of the sliding material 27 is located on the annular track A. The center of gravity of the sliding material 27 does not necessarily have to be located on the annular track A.

[0070] Similar to the first embodiment, the width of the sliding material 27 is narrower than the width of the leaf spring portion 6 and the width of the recess 5a in the rotor base portion 5. In this embodiment, the width of the sliding material 27 is the dimension along the direction perpendicular to the annular trajectory A in a plan view of the sliding material 27.

[0071] Figure 7 is a schematic plan view of the rotor according to the third embodiment. In Figure 7, the protruding parts of the sliding material, which will be described later, are shown with hatching.

[0072] The rotor 34 of this embodiment differs from the rotor 4 of the first embodiment in that the sliding material 37 has a plurality of protrusions 37a. Apart from the above, the rotor 34 of this embodiment has the same configuration as the rotor 4 of the first embodiment.

[0073] The sliding material 37 has an annular shape in plan view. The multiple protrusions 37a of the sliding material 37 are distributed in an annular trajectory. In other words, the multiple protrusions 37a are distributed along the circumferential direction of the traveling wave generated in the stator used with the rotor 34 in an ultrasonic motor. The multiple protrusions 37a protrude outward in the axial direction Z from the rotor body 4A side. Therefore, the multiple protrusions 37a protrude toward the vibrating body side of the stator. The multiple protrusions 37a of the sliding material 37 come into contact with the vibrating body.

[0074] In the sliding material 37, multiple protrusions 37a are connected to each other by portions other than the protrusions 37a. More specifically, the sliding material 37 has multiple protrusions 37a and multiple non-protrusions 37b. The thickness of the non-protrusions 37b is thinner than the thickness of the protrusions 37a. Adjacent protrusions 37a are connected to each other by the non-protrusions 37b. The configuration of the sliding material 37 is such that, in the circumferential direction of the traveling wave generated in the stator used with the rotor 34, portions that contact the vibrating body of the stator and portions that are thinner than those portions are alternately provided. This configuration makes it possible to lower the rigidity of the rotor 34 in the circumferential direction of the traveling wave.

[0075] This makes it easier to effectively follow the displacement of the vibrating body of the stator when a traveling wave is generated in the stator used with the rotor 34. This allows for more reliable contact between the wave crest and surrounding portion of the vibrating body and the sliding material 37 when a traveling wave is generated. Therefore, the contact area between the highly displaced portion of the vibrating body and the sliding material 37 in the rotor 34 can be increased. Consequently, the frictional force between the vibrating body and the rotor 34 can be increased, allowing the rotor 34 to rotate more reliably and efficiently.

[0076] In this embodiment, the sliding member 37 corresponds to a single member formed by connecting multiple sliding members 27 in the second embodiment. Specifically, the portion of the sliding member 37 corresponding to the multiple sliding members 27 is a multiple protrusion 37a. Since the sliding member 37 is a single member having the above configuration, the sliding member 37 is easy to handle, and the processing and assembly of the rotor 34 are easy. This makes it possible to increase the productivity of the rotor 34. Furthermore, the strength of the connection between the sliding member 37 and the leaf spring portion 6 in the rotor body 4A can be increased.

[0077] The thickness of the portion of the sliding material 37 other than the protruding portion 37a, i.e., the thickness of the non-protruding portion 37b, is preferably 70% or less of the thickness of the protruding portion 37a, and more preferably 30% or less. This makes it possible to more reliably reduce the rigidity of the rotor 34 in the circumferential direction of the traveling wave.

[0078] In addition, the sliding material 37 is made of carbon graphite. This allows for suppression of sticking, similar to the first embodiment.

[0079] In the sliding material 37, the width of the protruding portion 37a and the width of the non-protruding portion 37b are the same. However, it is not limited to this. For example, in a modified example of the third embodiment shown in Figure 8, in the sliding material 37A, the width of the non-protruding portion 37b is wider than the width of the protruding portion 37a. Because the width of the non-protruding portion 37b is wider, the strength of the connection between the sliding material 37A and the leaf spring portion 6 in the rotor body 4A can be effectively increased.

[0080] The sliding material 37A is made of carbon graphite. This allows for suppression of sticking, similar to the third embodiment.

[0081] Figure 9 is a schematic cross-sectional view of the rotor according to the fourth embodiment, showing a portion corresponding to the cross-section along line II in Figure 3.

[0082] The rotor 44 of this embodiment differs from the rotor 4 of the first embodiment in that the rotor body 44A consists only of the rotor base portion, and the rotor base portion does not have a recess. That is, the rotor 44 does not have a leaf spring portion. The rotor 44 of this embodiment also differs from the rotor 4 of the first embodiment in that it has a soft resin layer 48. Furthermore, the rotor 44 of this embodiment also differs from the rotor 4 of the first embodiment in that the width of the sliding material 7 is the same as the width of the rotor body 44A. Apart from the above points, the rotor 44 of this embodiment has the same configuration as the rotor 4 of the first embodiment.

[0083] In this specification, the soft resin layer 48 refers to a resin layer in which at least one of the Young's modulus and the flexural modulus is relatively low. Specifically, it is preferable that the Young's modulus of the soft resin layer 48 is 80% or less of the Young's modulus of the sliding material 7, or that the flexural modulus of the soft resin layer 48 is 80% or less of the flexural modulus of the sliding material 7.

[0084] For example, epoxy resin, phenolic resin, or polyphenylene sulfide (PPS) resin can be used for the flexible resin layer 48. Alternatively, the flexible resin layer 48 may be a resin layer in which the Young's modulus is adjusted to 80% or less of the Young's modulus of the sliding material 7, or the flexural modulus is adjusted to 80% or less of the flexural modulus of the sliding material 7, by adding additives to an appropriate resin. Alternatively, the flexible resin layer 48 may be a resin layer in which at least one of the Young's modulus and flexural modulus is adjusted to 7 GPa or less, by adding additives to an appropriate resin.

[0085] The soft resin layer 48 is provided between the rotor body 44A and the sliding material 7. That is, the rotor 44 has a structure in which the rotor body 44A, the soft resin layer 48, and the sliding material 7 are laminated in this order.

[0086] More specifically, in this embodiment, all parts of the sliding material 7 are provided on the soft resin layer 48. However, the sliding material 7 may include parts that are not provided on the soft resin layer 48. The rotor 44 is used in an ultrasonic motor together with a stator having a vibrating body. The portion where the sliding material 7 and the soft resin layer 48 are laminated only needs to overlap, in a plan view, with the wave crest portion and the surrounding portion of the vibrating body when a traveling wave is generated in the stator.

[0087] The soft resin layer 48 and the sliding material 7 may be joined together by a separate adhesive or other bonding agent. Alternatively, the soft resin layer 48 may be a bonding agent that joins the rotor body 44A and the sliding material 7.

[0088] As described above, the width of the sliding material 7 and the width of the rotor body 44A are the same. However, for example, the width of the sliding material 7 may be narrower than the width of the rotor body 44A.

[0089] Figure 10 is a schematic cross-sectional view showing the state in which the portion of the rotor shown in Figure 9 according to the fourth embodiment is in contact with the vibrating element of the stator, and a traveling wave is generated in the stator.

[0090] In this embodiment, a portion of the rotor 44 undergoes elastic deformation in response to the displacement of the vibrating body 3 caused by the traveling wave. More specifically, the soft resin layer 48 undergoes elastic deformation. Consequently, the sliding material 7 also deforms, as indicated by the arrows in Figure 10. This allows the sliding material 7 to come into contact with the wave crest portion and surrounding portion of the vibrating body 3 when the traveling wave is generated. Therefore, the contact area between the highly displaced portion of the vibrating body 3 and the sliding material 7 on the rotor 44 can be increased. Consequently, the frictional force between the vibrating body 3 and the rotor 44 can be increased, allowing the rotor 44 to rotate more reliably and efficiently.

[0091] The stator's resonance state changes as the soft resin layer 48 undergoes elastic deformation in response to the displacement of the vibrating body 3 in the stator. Specifically, a portion of the vibration energy in the stator is converted into heat due to the elastic deformation of the soft resin layer 48. In other words, the vibration energy in the stator is absorbed. As a result, the mechanical quality coefficient Qm of the stator's resonance state decreases, and the amplitude of the vibrating body 3 in the stator decreases. Note that the larger the amplitude of the vibrating body 3, the higher the maximum rotational speed of the ultrasonic motor. On the other hand, the elastic deformation of the soft resin layer 48 also widens the frequency range in which the stator resonates. This effect is called the damping effect.

[0092] The damping effect makes it easier to bring the stator into a resonant state, even when there are variations in the stator's vibration. Therefore, even when there are variations in the stator's vibration, the rotor 44 can be rotated smoothly, and the ultrasonic motor can be driven smoothly.

[0093] Furthermore, by adjusting the Young's modulus or flexural modulus of the soft resin layer 48 through the selection of the material for the soft resin layer 48, the balance between the amplitude of vibration in the vibrating body 3 and the frequency range in which the stator resonates can be adjusted. Alternatively, the above balance can also be adjusted by adjusting the thickness of the soft resin layer 48.

[0094] In addition, the sliding material 7 is made of carbon graphite. This makes it possible to suppress sticking, similar to the first embodiment.

[0095] Incidentally, even when the soft resin layer 48 is provided, the leaf spring portion 6 shown in Figure 4 may also be provided. For example, in the modified version of the fourth embodiment shown in Figure 11, the rotor base portion 5 of the rotor body 4A has a recess 5a. The leaf spring portion 6 is provided on the rotor base portion 5 so as to cover the recess 5a. The soft resin layer 48 is provided between the leaf spring portion 6 and the sliding material 7. That is, the sliding material 7 is provided indirectly on the leaf spring portion 6 via the soft resin layer 48. In other words, the leaf spring portion 6, the soft resin layer 48 and the sliding material 7 are laminated in this order.

[0096] In plan view, all parts of the sliding material 7 overlap with the recess 5a of the rotor base portion 5. The width of the sliding material 7 is narrower than the width of the leaf spring portion 6 and the width of the recess 5a.

[0097] The rotor 54 is used in an ultrasonic motor together with a stator having a vibrating body. The leaf spring portion 6 and the soft resin layer 48 elastically deform in accordance with the displacement of the vibrating body caused by the traveling wave. As the soft resin layer 48 elastically deforms, the sliding material 7 also elastically deforms. This allows for more reliable contact between the wave crest portion and the surrounding portion of the vibrating body when a traveling wave is generated and the sliding material 7. Therefore, the contact area between the highly displaced portion of the vibrating body and the sliding material 7 on the rotor 54 can be more reliably increased. Consequently, the frictional force between the vibrating body and the rotor 54 can be increased, and the rotor 54 can be rotated more reliably and efficiently.

[0098] Similar to the fourth embodiment, the damping effect allows the rotor 54 to rotate smoothly and the ultrasonic motor to be driven smoothly, even when there are variations in the stator's vibration. By adjusting the Young's modulus or flexural modulus of the soft resin layer 48 by selecting the material of the soft resin layer 48, the balance between the amplitude of vibration in the stator's vibrating body and the range of frequencies in which the stator resonates can be adjusted. Alternatively, the above balance can also be adjusted by adjusting the thickness of the soft resin layer 48.

[0099] Furthermore, the absorption of vibration energy in the stator also occurs due to the elastic deformation of the leaf spring section 6, which follows the displacement of the vibrating body in the stator. The degree of elastic deformation of the leaf spring section 6 can be adjusted by selecting the material of the leaf spring section 6, adjusting the thickness of the leaf spring section 6, or adjusting the width of the recess 5a in the rotor base section 5. This allows for adjustment of the amount of vibration energy absorbed in the stator due to the elastic deformation of the leaf spring section 6.

[0100] In this modified example, the sliding material 7 is made of carbon graphite. This allows for suppression of sticking, similar to the fourth embodiment.

[0101] The rotor 54 may have, instead of the sliding material 7, a plurality of sliding materials 27 in the second embodiment shown in Figure 6 or a sliding material 37 in the third embodiment shown in Figure 7. In these cases, the circumferential rigidity of the traveling wave generated in the stator used with the rotor 54 can be reduced. This allows for increased friction between the stator vibrator and the rotor 54, similar to the second and third embodiments, enabling the rotor 54 to rotate more reliably and efficiently.

[0102] Similarly, the rotor 44 of the fourth embodiment may have, instead of the sliding material 7, a plurality of sliding materials 27 in the second embodiment shown in Figure 6 or a sliding material 37 in the third embodiment shown in Figure 7. In these cases, the circumferential rigidity of the traveling wave generated in the stator used with the rotor 44 can be reduced. This allows for increased friction between the stator vibrator and the rotor 44, as in the second and third embodiments, enabling the rotor 44 to rotate more reliably and efficiently.

[0103] Figure 12 is a schematic bottom view of a stator according to a fifth embodiment of the present invention.

[0104] The stator 62 of this embodiment differs from the stator 2 of the first embodiment in that it has a sliding material 7. Apart from the above, the stator 62 of this embodiment has the same configuration as the stator 2 of the first embodiment.

[0105] A sliding material 7 is provided on the second main surface 3b of the vibrating body 3 in the stator 62. The sliding material 7 has the same configuration as the sliding material 7 of the rotor 4 in the first embodiment. Specifically, the shape of the sliding material 7 in this embodiment in plan view is an annular shape. The sliding material 7 is made of carbon graphite.

[0106] The sliding material 7 is provided so as to surround the through-hole 3c of the vibrating body 3 in the stator 62. The stator 62 is used together with the rotor in an ultrasonic motor. The sliding material 7 in the stator 62 is a component that comes into contact with the rotor. When the ultrasonic motor is driven, the surface of the rotor slides against the sliding material 7. Therefore, when the ultrasonic motor is driven, relatively speaking, the sliding material 7 in the stator 62 slides against the surface of the rotor.

[0107] The configuration of the rotor used with the stator 62 is not particularly limited. It is sufficient that resin is not used as the material for the part of the rotor that comes into contact with the sliding material 7.

[0108] When driving the ultrasonic motor using the stator 62 of this embodiment, even if wear particles are generated from the sliding material 7 made of carbon graphite, no water-soluble components that function as an adhesive are generated. Therefore, even in environments with high humidity where the rotor and stator 62 are exposed to moisture, solidification is less likely to occur at the contact points between the rotor and stator 62 in the ultrasonic motor. This suppresses sticking. As a result, the ultrasonic motor can be used suitably even in harsh environments with high humidity.

[0109] The stator 62 may have, for example, multiple sliding materials 27 in the second embodiment shown in Figure 6, or a sliding material 37 in the third embodiment shown in Figure 7, instead of the sliding material 7. Alternatively, the stator 62 may have, for example, a sliding material 37A in a modified example of the third embodiment shown in Figure 8, instead of the sliding material 7.

[0110] Figure 13 is a schematic bottom view of the stator according to the sixth embodiment. Figure 14 is a schematic cross-sectional view along the line II-II in Figure 13. Piezoelectric elements are omitted in Figures 13 and 14.

[0111] As shown in Figures 13 and 14, this embodiment differs from the fifth embodiment in that a plurality of protrusions 73e are provided on the second main surface 73b of the vibrating body 73. This embodiment also differs from the fifth embodiment in that a plurality of sliding members 27 are provided. Apart from the above, the stator 72 of this embodiment has the same configuration as the stator 62 of the fifth embodiment. Thus, the vibrating body 73 has a first main surface 73a and a second main surface 73b, and the vibrating body 73 is provided with a through hole 73c.

[0112] As mentioned above, piezoelectric elements are omitted in Figures 13 and 14. However, in this embodiment, as in the fifth embodiment, a plurality of piezoelectric elements are provided on the first main surface 73a of the vibrating body 73.

[0113] The second main surface 73b of the vibrating body 73 is provided with a plurality of protrusions 73e surrounding the through hole 73c. ​​The plurality of protrusions 73e are dispersed in an annular trajectory. Specifically, this annular trajectory is a circular trajectory. In other words, the plurality of protrusions 73e are dispersed along the circumferential direction of the traveling wave generated in the stator 72.

[0114] The multiple protrusions 73e project outward in the axial direction Z from the second main surface 73b of the vibrating body 73. When the stator 72 is used in an ultrasonic motor together with the rotor, the multiple protrusions 73e project toward the rotor.

[0115] Each of the multiple protrusions 73e is provided with one sliding material 27. Therefore, the multiple sliding materials 27 are distributed along the circumferential direction of the traveling wave generated in the stator 72, similar to the multiple protrusions 73e. The multiple sliding materials 27 contact the rotor.

[0116] Multiple sliding materials 27 are made of carbon graphite. This allows for suppression of sticking, similar to the fifth embodiment.

[0117] In addition, in this embodiment, the multiple protrusions 73e project outward from the second main surface 73b in the axial direction Z. As a result, when a traveling wave is generated in the vibrating body 73 of the stator 72, the tips of the multiple protrusions 73e are displaced even more significantly. The rotor then comes into contact with the sliding material 27 provided on the surface of the tips of the protrusions 73e on the second main surface 73b. Therefore, the rotor can be rotated efficiently by the traveling wave generated in the stator 72.

[0118] The displacement of the traveling wave generated in the stator 72 is specifically the displacement due to the deflection deformation of the vibrating body 73. This displacement due to deflection deformation is a displacement in a direction parallel to the axial direction Z. Therefore, when a traveling wave is generated, deflection deformation occurs in the first main surface 73a and the second main surface 73b of the vibrating body 73. As described above, the tips of the multiple protrusions 73e provided on the second main surface 73b are displaced even more significantly.

[0119] However, deflection deformation is unlikely to occur on the surface of the tip of each projection 73e where each sliding material 27 is provided. Therefore, deflection deformation is unlikely to occur even with multiple sliding materials 27. As a result, the energy loss of the stator 72 due to the deflection deformation of multiple sliding materials 27 is reduced. This allows the ultrasonic motor to be driven efficiently.

[0120] Furthermore, in each sliding material 27 made of carbon graphite, there is a concern that cracking may occur due to excessive deflection deformation. In contrast, in this embodiment, deflection deformation is unlikely to occur in each sliding material 27. Therefore, cracking in each sliding material 27 can be suppressed even more reliably.

[0121] The ultrasonic motor according to the present invention may, for example, have a rotor according to the present invention and a suitable stator. Alternatively, the ultrasonic motor according to the present invention may have a suitable rotor and a suitable stator. This makes it possible to suppress sticking.

[0122] Examples of the rotor, stator, and ultrasonic motor configurations according to the present invention are described below.

[0123] <1> A rotor used in an ultrasonic motor, comprising a stator having a vibrating body and a vibration generating element provided on the vibrating body, the rotor comprising a rotor body and a sliding material provided on the rotor body and in contact with the vibrating body, wherein the sliding material is made of carbon graphite.

[0124] <2> Raman spectroscopy was performed using an incident laser wavelength of 532 nm and a grating type of 600 gr / m to obtain the Raman spectrum of the carbon-graphite material used in the sliding material. When the peak value of the D band is D, the peak value of the G band is G, and the degree of graphitization of the carbon-graphite material is R, then R = D / G, and the degree of graphitization R of the carbon-graphite material is between 0.5 and 1.2. <1> The rotor described above.

[0125] <3> The rotor body comprises a rotor base portion having a recess and a leaf spring portion provided on the rotor base portion so as to cover the recess, and the sliding material is provided on the leaf spring portion. <1> or <2> The rotor described above.

[0126] <4> The system further comprises a soft resin layer provided between the leaf spring portion and the sliding material. <3> The rotor described above.

[0127] <5> The rotor body and the sliding material are further provided with a soft resin layer, <1> or <2> The rotor described above.

[0128] <6> The device comprises a plurality of the aforementioned sliding members, wherein, in a plan view, the plurality of sliding members are dispersed and arranged in an annular track. <1> ~ <5> The rotor listed in one of the following.

[0129] <7> The sliding material includes a plurality of protrusions that are dispersed in an annular trajectory in a plan view, and the plurality of protrusions protrude toward the vibrating body. <1> ~ <5> The rotor listed in one of the following.

[0130] <8> A stator used in an ultrasonic motor equipped with a rotor, comprising a vibrating body, a vibration generating element provided on the vibrating body, and a sliding material provided on the vibrating body and in contact with the rotor, wherein the sliding material is made of carbon graphite.

[0131] <9> Raman spectroscopy was performed using an incident laser wavelength of 532 nm and a grating type of 600 gr / m to obtain the Raman spectrum of the carbon-graphite material used in the sliding material. When the peak value of the D band is D, the peak value of the G band is G, and the degree of graphitization of the carbon-graphite material is R, then R = D / G, and the degree of graphitization R of the carbon-graphite material is between 0.5 and 1.2. <8> The status listed.

[0132] <10> <1> ~ <7> An ultrasonic motor comprising a rotor as described in any one of the above, a stator having the vibrating body and the vibration generating element provided on the vibrating body.

[0133] <11> <8> or <9> An ultrasonic motor comprising the stator described in [reference] and the rotor. [Explanation of Symbols]

[0134] 1… Ultrasonic motor 2…Status 3…Vibrating body 3a, 3b…First and second principal surfaces 3c...Through hole 3d…Contact surface 4…Rotor 4A...Rotor body 4c...Through hole 5…Rotor base section 5a…recess 5b,5c…Groove 6…Leaf spring section 6a, 6b… First and second faces 7…Sliding material 8…First case component 8a, 8b... First and second cylindrical protrusions 8c…Through hole 9…Second case component 9a...Cylindrical projection 9c...Through hole 10...Shaft member 10a... Wide section 12…Elastic member 13… Piezoelectric element 14… Piezoelectric material 14a, 14b… Third and fourth main surfaces 15A, 15B... First and second electrodes 16... Spring component 16c...Through hole 17… Retaining ring 18, 19... First and second bearing sections 24...Rota 27…Sliding material 34…Rota 37,37A…Sliding material 37a...Protruding part 37b…Non-protruding part 44...Rota 44A...Rotor body 48…Soft resin layer 54...Rota 62,72…Status 73…Vibrating body 73a, 73b… First and second main surfaces 73c...Through hole 73e…Protrusion

Claims

1. A rotor used in an ultrasonic motor, comprising a stator having a vibrating body and a vibration generating element provided on the vibrating body, The rotor body and A sliding material provided on the rotor body and in contact with the vibrating body, Equipped with, A rotor in which the sliding material is made of carbon graphite.

2. Raman spectroscopy was performed using a Raman method with an incident laser wavelength of 532 nm and a grating type of 600 gr / m to obtain the Raman spectrum of the carbon-graphite material used in the sliding material. When the peak value of the D band is D, the peak value of the G band is G, and the degree of graphitization of the carbon-graphite material is R, then R = D / G. The rotor according to claim 1, wherein the degree of graphitization R of the carbon graphite is 0.5 or more and 1.2 or less.

3. The rotor body comprises a rotor base portion having a recess and a leaf spring portion provided on the rotor base portion so as to cover the recess, The rotor according to claim 1, wherein the sliding material is provided on the leaf spring portion.

4. The rotor according to claim 3, further comprising a soft resin layer provided between the leaf spring portion and the sliding material.

5. The rotor according to claim 1, further comprising a soft resin layer provided between the rotor body and the sliding material.

6. The device comprises multiple sliding materials, The rotor according to claim 1, wherein the plurality of sliding materials are arranged in a dispersed manner in an annular trajectory in a plan view.

7. The rotor according to claim 1, wherein the sliding material includes a plurality of protrusions distributed in an annular trajectory in a plan view, and the plurality of protrusions protrude toward the vibrating body.

8. A stator used in an ultrasonic motor equipped with a rotor, A vibrating body and A vibration generating element provided on the vibrating body, A sliding material provided on the vibrating body and in contact with the rotor, Equipped with, A stator in which the sliding material is made of carbon graphite.

9. Raman spectroscopy was performed using a Raman method with an incident laser wavelength of 532 nm and a grating type of 600 gr / m to obtain the Raman spectrum of the carbon-graphite material used in the sliding material. When the peak value of the D band is D, the peak value of the G band is G, and the degree of graphitization of the carbon-graphite material is R, then R = D / G. The stator according to claim 8, wherein the degree of graphitization R of the carbon graphite is 0.5 or more and 1.2 or less.

10. The rotor according to claim 1, The stator having the vibrating body and the vibration generating element provided on the vibrating body, An ultrasonic motor equipped with [a specific feature].

11. The stator according to claim 8, The rotor and, An ultrasonic motor equipped with [a specific feature].

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