Rotor, stator, and ultrasonic motor

Abstract

The invention provides a rotor capable of suppressing jamming. The rotor (4) is used for an ultrasonic motor (1), the ultrasonic motor (1) is provided with a stator (2), the stator (2) is provided with a vibrating body (3) and a vibration generating element (piezoelectric element (13)) arranged on the vibrating body (3), the rotor (4) is provided with a rotor main body (4A) and a sliding piece (7) arranged on the rotor main body (4A) and contacted with the vibrating body (3), and the sliding piece (7) is made of carbon graphite.

Description

TECHNICAL FIELD

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

[0002] Conventionally, various ultrasonic motors have been proposed which vibrate a stator using a piezoelectric element. One example of an ultrasonic motor is disclosed in Patent Literature 1 described below. In this ultrasonic motor, a traveling vibration wave generated in the stator is used to rotate a rotor.

[0003] The stator in Patent Literature 1 is formed by bonding a ring-shaped piezoelectric body to a ring-shaped elastic body. A traveling vibration wave is generated in the elastic body by vibration of the piezoelectric body. On the other hand, the rotor is formed by bonding a ring-shaped sliding member to a ring-shaped rotor base material. The sliding member in the rotor is in contact with the elastic body in the stator. Moreover, when the rotor rotates, the sliding member slides on the surface of the elastic body. The sliding member in Patent Literature 1 is composed of resin.

[0004] [Related Art]

[0005] [Patent Literature]

[0006] [Patent Literature 1] Japanese Patent Application Laid-Open (kokai) No. 3-074182 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] When an ultrasonic motor using a sliding member composed of resin is used in an environment with high humidity, or the like, there is a case where the rotor adheres to the stator, the stator and the rotor are fixed to each other, and the ultrasonic motor cannot be started. This phenomenon is called "stuck".

[0009] When a sliding member composed of resin slides on the surface of a stator, a wear powder which is finely ground due to mechanical friction, and a low-molecular component which is decomposed due to frictional heat are generated from the sliding member. The present inventors have found that a water-soluble component is contained in the low-molecular component generated from the sliding member. The present inventors have found that, when the water-soluble component, or a mixture of the water-soluble component and the wear powder, is exposed to moisture and then dried, a function as an adhesive is exhibited, and as a result, the stator and the rotor can be fixed to each other. As a result, stuck can occur.

[0010] In the case where stuck occurs, even if a signal for driving is applied, the ultrasonic motor cannot be started. Therefore, stuck becomes a fatal failure of the ultrasonic motor.

[0011] An object of the present application is to provide a rotor, a stator, and an ultrasonic motor which can suppress stuck.

[0012] [Means for Solving the Problems]

[0013] The rotor of the present application is a rotor for an ultrasonic motor having a stator, the stator having a vibration body and a vibration generating element provided on the vibration body, wherein the rotor comprises: a rotor main body; and a sliding member provided on the rotor main body and in contact with the vibration body, the sliding member being composed of carbon graphite.

[0014] The stator of the present application is a stator for an ultrasonic motor having a rotor, wherein the stator comprises: a vibration body; a vibration generating element provided on the vibration body; and a sliding member provided on the vibration body and in contact with the rotor, the sliding member being composed of carbon graphite.

[0015] In one broad aspect of the ultrasonic motor of the present application, the ultrasonic motor comprises: a rotor configured according to the present application; and the stator having the vibration body and the vibration generating element provided on the vibration body.

[0016] In another broad aspect of the ultrasonic motor of the present application, the ultrasonic motor comprises a stator configured according to the present application, and the rotor.

[0017] [Effects of the Invention]

[0018] According to the rotor, the stator and the ultrasonic motor of the present application, seizure can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic front cross-sectional view of an ultrasonic motor of Embodiment 1 of the present application.

[0020] Figure 2 is a schematic plan view of a stator in Embodiment 1 of the present application.

[0021] Figure 3 is a schematic plan view of a rotor in Embodiment 1 of the present application.

[0022] Figure 4 is a schematic cross-sectional view along the line I-I in Figure 3

[0023] Figure 5 is a schematic front cross-sectional view of a piezoelectric element in Embodiment 1 of the present application.

[0024] Figure 6 is a schematic plan view of a rotor of Embodiment 2 of the present application.

[0025] Figure 7 is a schematic plan view of a rotor of Embodiment 3 of the present application.

[0026] Figure 8 ​is a schematic plan view of a rotor of a modification of the 3rd embodiment of the present application.

[0027] Figure 9 is a schematic sectional view of a portion corresponding to a section along the I-I line in Figure 3

[0028] Figure 10 is a schematic sectional view of a portion corresponding to a section along the I-I line in Figure 9

[0029] Figure 11 is a schematic sectional view of a portion corresponding to a section along the I-I line in Figure 3

[0030] Figure 12 is a schematic bottom view of a stator of the 5th embodiment of the present application.

[0031] Figure 13 is a schematic bottom view of a stator of the 6th embodiment of the present application.

[0032] Figure 14 is a schematic sectional view along the II-II line in Figure 13 DETAILED DESCRIPTION

[0033] Hereinafter, specific embodiments of the present application will be described with reference to the drawings, whereby the present application will be apparent.

[0034] Further, each of the embodiments described in this specification is illustrative, and it should be noted that partial substitution or combination of structures is possible between different embodiments.

[0035] Figure 1 is a schematic front sectional view of an ultrasonic motor of the 1st embodiment of the present application.

[0036] The ultrasonic motor 1 has a stator 2, a rotor 4, and a shaft member 10. The stator 2 is in contact with the rotor 4. The rotor 4 is a rotor of an embodiment of the present application. The rotor 4 rotates by a traveling wave generated in the stator 2. The shaft member 10 rotates as the rotor 4 rotates. The center axis of rotation of the ultrasonic motor 1 is located at a portion where the shaft member 10 is provided. Hereinafter, the specific structure of the ultrasonic motor 1 will be described.

[0037] Figure 2 is a schematic plan view of the stator in the 1st embodiment.

[0038] ​​​​The stator 2 has a plate-shaped vibration body 3. The vibration body 3 has a circular plate shape. The vibration 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.

[0039] A through-hole 3c is provided in a central portion of the vibration body 3. As shown in FIG. 1, a shaft member 10 is inserted through the through-hole 3c. Note that the position of the through-hole 3c is not limited to the central portion of the vibration body 3. The through-hole 3c can be positioned in a region including the rotation center axis. Also, the shape of the vibration body 3 is not limited to a circular plate shape. Figure 1

[0040] In the present specification, the axial direction Z refers to a direction connecting the first main surface 3a and the second main surface 3b, and is a direction along the rotation center axis. In the present embodiment, the axial direction Z is parallel to the direction in which the shaft member 10 extends. The shape of the vibration body 3 as viewed from the axial direction Z can be, for example, a regular polygon such as a regular hexagon, a regular octagon, or a regular decagon. In the present specification, a polygon also includes cases in which the portion corresponding to the vertex is a curved line, and cases in which the shape is chamfered. Hereinafter, the case in which the shape is viewed from the axial direction Z will be sometimes referred to as plan view.

[0041] The vibration body 3 is composed of a suitable metal. Of course, the vibration body 3 can not necessarily be composed of a metal. The vibration body 3 can be composed of another elastic body such as ceramic or silicon material, for example.

[0042] As shown in FIG. 1, a plurality of piezoelectric elements 13 are provided on the first main surface 3a of the vibration body 3. The piezoelectric elements 13 are vibration generating elements in the present application. When viewed in plan view, the plurality of piezoelectric elements 13 are arranged dispersedly in the circumferential direction. More specifically, the plurality of piezoelectric elements 13 are arranged dispersedly in the circumferential direction of a traveling wave generated so as to have a center axis parallel to the axial direction Z. In the stator 2, a configuration in which the plurality of piezoelectric elements 13 are arranged dispersedly in the circumferential direction and generate a traveling wave by driving is disclosed, for example, in International Publication No. 2010 / 061508. Therefore, detailed description of generation of the traveling wave is omitted. Figure 2

[0043] Figure 3 is a schematic plan view of the rotor in the first embodiment.

[0044] The rotor 4 has a rotor main body 4A and a slider 7. The shape of the rotor main body 4A when viewed in plan view is a circular ring shape. A through-hole 4c is provided in a central portion of the rotor main body 4A. A shaft member 10 is inserted through the through-hole 4c. Figure 1 ​​The shaft member 10 is shown. However, the position of the through-hole 4c is not limited to the central portion of the rotor body 4A. The through-hole 4c can be located in a region including the rotational center axis. Also, the shape of the rotor body 4A is not limited to the shape described above. The outer shape of the rotor body 4A in plan view can be, for example, a regular polygon such as a regular hexagon, a regular octagon, or a regular decagon.

[0045] The slider 7 is provided on the rotor body 4A. The shape of the slider 7 in plan view is a circular ring shape. The slider 7 is provided so as to surround the through-hole 4c of the rotor body 4A. The slider 7 is a member that contacts the stator 2. Figure 1 The stator 2 shown is a member that contacts the stator 2. In the present embodiment, specifically, the slider 7 of the rotor 4 contacts the vibration body 3 in the stator 2. When the ultrasonic motor 1 is driven to rotate the rotor 4, the slider 7 of the rotor 4 slides on the surface of the vibration body 3 of the stator 2.

[0046] The slider 7 is composed of a carbon graphite. The carbon graphite refers to a carbon-based material in which the graphitization degree R=D / G is 0.5 or more and 1.2 or less. More specifically, the peak value of the D band in the Raman spectrum of the carbon graphite obtained by Raman spectroscopy is D. The peak value of the G band in the Raman spectrum is G. In addition, the D band is a frequency band of 1360 cm -1 or more in the Raman spectrum. The G band is a frequency band of 1580 cm -1 or less in the Raman spectrum. Also, the graphitization degree R of the carbon graphite is a value obtained by dividing the peak value D by the peak value G.

[0047] In calculating the graphitization degree R in the present specification, the Raman spectrum of the carbon graphite for the slider is obtained by Raman spectroscopy in which the wavelength of the incident laser light is set to 532 nm and the type of the grating is set to 600 gr / m. Next, the peak value D and the peak value G in the obtained Raman spectrum are found. Next, R=D / G is calculated using the found peak value D and the peak value G.

[0048] In addition, it is preferable to find the peak value D and the peak value G after smoothing the Raman spectrum by a Savizky-Golay-2nd filter.

[0049] If the graphitization degree R of the carbon graphite that constitutes the slider 7 is too high, the lubricity of the slider 7 can decrease. On the other hand, if the graphitization degree R of the carbon graphite that constitutes the slider 7 is too low, the wear resistance of the slider 7 can decrease.

[0050] When obtaining the carbon-graphite material constituting the sliding member 7, carbon powder is solidified, for example, by compression molding, to obtain a carbon solid. Then, a portion of the carbon solid is crystallized by heat treatment. In other words, a portion of the carbon solid is converted from carbon to graphite. Thus, carbon-graphite is obtained. However, carbon-graphite is a substance that has undergone partial crystallization of the carbon solid; carbon-graphite is a type of amorphous carbon.

[0051] like Figure 3 As shown, the rotor body 4A has a rotor base portion 5 and a leaf spring portion 6. The top view of the rotor body 4A is the same as the top view of the rotor base portion 5. Furthermore, a through hole 4c is provided in the rotor base portion 5 of the rotor body 4A. On the other hand, the leaf spring portion 6 has a ring-shaped shape when viewed from above. The leaf spring portion 6 is provided to surround the through hole 4c. Suitable metals or suitable ceramics can be used as the material for the rotor base portion 5. Suitable metals can be used as the material for the leaf spring portion 6.

[0052] Figure 4 It is along Figure 3 A schematic cross-sectional view of line II in the diagram. Figure 4 The dashed lines in the diagram schematically represent the displacement of the leaf spring section, which will be described later.

[0053] The rotor base portion 5 has a recess 5a. Although not shown, the recess 5a is annular in shape when viewed from above. A leaf spring portion 6 is provided on the rotor base portion 5 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 are opposite to each other. The first surface 6a is located on the first surface 6a of the first surface 6a and the second surface 6b. Figure 1 The stator side 2 is shown.

[0054] The aforementioned sliding member 7 is provided on the leaf spring portion 6 of the rotor body 4A. Furthermore, in this specification, the case of providing other components on a certain component includes cases where other components are directly provided on a certain component, and cases where other components are indirectly provided on a certain component through other layers. In this embodiment, the sliding member 7 is directly provided on the leaf spring portion 6. The sliding member 7 may also be joined to the leaf spring portion 6 by a joining member such as an adhesive.

[0055] All parts of the slider 7 overlap with the recess 5a of the rotor base portion 5 when viewed from above. The width of the slider 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 slider 7 is the distance between the inner and outer peripheries of the slider 7 when viewed from above. The width of the leaf spring portion 6 and the width of the recess 5a are also the same.

[0056] Return to Figure 3The feature of this embodiment is that a sliding member 7 is provided on the rotor body 4A of the rotor 4, and the sliding member 7 is made of carbon graphite. Therefore, even when using the ultrasonic motor 1 utilizing the rotor 4 in environments with high humidity, jamming can be suppressed. Furthermore, jamming refers to the phenomenon where the rotor is adhered to the stator, the stator and rotor are fixed together, and the ultrasonic motor cannot be started. The above effects will be explained in detail below.

[0057] In the driver Figure 1 In the ultrasonic motor 1 shown, the sliding member 7 of the rotor 4 slides on the surface of the vibrating body 3 of the stator 2. At this time, even if wear powder is generated from the sliding member 7, which is made of carbon graphite, no water-soluble components that function as adhesives are produced. Therefore, even in environments with high humidity and where the rotor 4 and stator 2 are exposed to moisture, it is difficult for the rotor 4 and stator 2 to solidify at their contact points in the ultrasonic motor 1. This prevents jamming. Therefore, the ultrasonic motor 1 can be used appropriately even in harsh environments with high humidity.

[0058] like Figure 4 As shown, the rotor base portion 5 preferably has a recess 5a, and a leaf spring portion 6 is provided on the rotor base portion 5 to cover the recess 5a. Furthermore, a sliding member 7 is preferably provided on the leaf spring portion 6. This allows the rotor 4 to rotate efficiently. This will be explained below.

[0059] exist Figure 1 In the stator 2 shown, the vibrating body 3 is displaced due to the vibration of the piezoelectric element 13, which serves as the vibration generating element, thus generating a traveling wave. During the generation of the traveling wave, there are portions of the vibrating body 3 with larger displacements and portions with smaller displacements. More specifically, the displacement is greatest at the crest of the traveling wave in the vibrating body 3. The displacement is also large at the periphery of the crest in the vibrating body 3. When the area of ​​contact between the portion of the vibrating body 3 with the rotor 4 is large, the rotor 4 can rotate efficiently.

[0060] In this embodiment, as Figure 4 As shown, a sliding member 7 is provided on the leaf spring section 6. Therefore, following the displacement of the vibrating body 3 caused by the traveling wave, the leaf spring section 6 moves as follows... Figure 4 The rotor 3 deforms elastically like the dotted line in the diagram. This allows the crest and surrounding portion of the vibrating body 3, which generates a traveling wave, to contact the sliding member 7. Therefore, the contact area between the portion of the vibrating body 3 undergoing a large displacement and the sliding member 7 of the rotor 4 can be increased. Consequently, the frictional force between the vibrating body 3 and the rotor 4 can be increased, enabling the rotor 4 to rotate efficiently.

[0061] The rotor base portion 5 has a recess 5a. A structure in which a leaf spring portion 6 is provided on the rotor base portion 5 to cover the recess 5a can also be applied to structures of the present invention other than this embodiment. However, in the present invention, the rotor body 4A may not necessarily have a leaf spring portion 6. The rotor base portion 5 may not necessarily have a recess 5a. The sliding member 7 can be provided on the rotor body 4A in a manner that contacts the stator 2.

[0062] The structure of this embodiment will be described in more detail below.

[0063] like Figure 1 As shown, the ultrasonic motor 1 has a first housing member 8 and a second housing member 9. The second housing member 9 is cap-shaped, and the first housing member 8 is cover-shaped. The housing is formed by the first housing member 8 and the second housing member 9. Inside the housing, a spring member 16, a rotor 4, and a stator 2 are disposed.

[0064] The first housing member 8 has a first cylindrical protrusion 8a and a second cylindrical protrusion 8b. The first cylindrical protrusion 8a protrudes outward from the housing. The second cylindrical protrusion 8b protrudes inward from the housing. A portion of the second cylindrical protrusion 8b is located within the through hole 3c of the vibrating body 3 of the stator 2.

[0065] Through holes 8c are continuously provided in the first cylindrical protrusion 8a and the second cylindrical protrusion 8b. A first bearing portion 18 is provided in the portion of the first cylindrical protrusion 8a within the through hole 8c. A 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 housing member 8. However, the structure of the first housing member 8 is not limited to the structure described above.

[0066] The second housing member 9 has a cylindrical protrusion 9a. The cylindrical protrusion 9a protrudes outward from the housing. A through hole 9c is provided in the cylindrical protrusion 9a. A second bearing portion 19 is provided in the through hole 9c. A shaft member 10 is inserted through the through hole 9c and the second bearing portion 19. The shaft member 10 protrudes outward from the through hole 9c of the second housing member 9. Furthermore, the structure of the second housing member 9 is not limited to the above-described structure. For example, sliding bearings or rolling bearings may be used for the first bearing portion 18 and the second bearing portion 19.

[0067] The sliding member 7 of the rotor 4 contacts 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 contacts the rotor 4. The contact surface 3d is planar. More specifically, no uneven structure is provided on the contact surface 3d. The contact surface 3d is constructed in the same way as the portion of the second main surface 3b other than the contact surface 3d. Therefore, when obtaining the stator 2 of this embodiment, it is not necessary to cut the second main surface 3b of the vibrating body 3. Therefore, the productivity of the ultrasonic motor 1 can be improved.

[0068] An elastic member 12 is provided on the rotor base portion 5 of the rotor 4. More specifically, the elastic member 12 clamps 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 shape. As a material for the elastic member 12, rubber or resin can be used, for example. However, the elastic member 12 may not be provided.

[0069] A spring member 16 is disposed on the side of the second bearing portion 19 of the elastic member 12. More specifically, the spring member 16 in this embodiment is a leaf spring made of metal. A through hole 16c is provided in the central portion of the spring member 16. A 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 portions of the shaft member 10. In addition, the width of the shaft member 10 is a dimension along a direction orthogonal to the axial direction Z of the shaft member 10. The inner peripheral edge of the spring member 16 abuts against the wide portion 10a. As a result, positional misalignment between the spring member 16 and the shaft member 10 can be suppressed. However, the material and structure of the spring member 16 are not limited to the above. The structure of the shaft member 10 is also not limited to the above structure.

[0070] A spring force is applied to the rotor 4 via the spring member 16 and the elastic member 12. As a result, the rotor 4 is pressed against the stator 2. This increases the friction between the stator 2 and the rotor 4. Therefore, traveling waves can be effectively propagated from the stator 2 to the rotor 4, enabling the rotor 4 to rotate efficiently. Consequently, the ultrasonic motor 1 can be driven more reliably and efficiently.

[0071] like Figure 1 As shown, a retaining ring 17 is provided on the shaft member 10. The retaining ring 17 has an annular shape. When viewed from above, 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 outer side in the axial direction Z. Thus, the length between the retaining ring 17 and the wide portion 10a of the shaft member 10 determines the amount of deflection of the spring member 16. Thus, as described above, the elastic force of the spring member 16 can be imparted to the rotor 4. For example, metal or resin can be used as the material for the shaft member 10 and the retaining ring 17.

[0072] As Figure 2 shown, the stator 2 has a plurality of piezoelectric elements 13. Hereinafter, a specific structure of the piezoelectric element 13 is shown.

[0073] Figure 5 is a schematic front sectional view of the piezoelectric element in the first embodiment.

[0074] 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 includes 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. A shape of the piezoelectric element 13 in plan view is rectangular. In addition, the shape of the piezoelectric element 13 in plan view is not limited to the above, and for example, can be an elliptical shape or the like.

[0075] In the present embodiment, the stator 2 has four piezoelectric elements 13. In addition, the number of the piezoelectric elements 13 is not limited to the above. The plurality of piezoelectric elements 13 can be arranged in a dispersed manner along a circumferential direction of a traveling wave generated so as to circulate around an axis parallel to the axial direction Z.

[0076] Alternatively, the stator 2 can have one piezoelectric element divided into a plurality of regions. In this case, for example, each region of the piezoelectric element can be polarized in a different direction from each other. A shape of the piezoelectric element in plan view is, for example, a circular ring shape.

[0077] Here, Figure 5 The first electrode 15A shown is adhered to the first main surface 3a of the vibrating body 3 by an adhesive. The thickness of the adhesive is very thin. Therefore, the first electrode 15A is electrically connected to the vibrating body 3.

[0078] As Figure 4 shown, the rotor base portion 5 is provided with a groove portion 5b in a manner connected to the inner periphery of the recessed portion 5a. Similarly, the rotor base portion 5 is provided with a groove portion 5c in a manner connected to the outer periphery of the recessed portion 5a. The shapes of the groove portion 5b and the groove portion 5c in plan view are circular ring shapes, respectively. A leaf spring portion 6 is provided from the groove portion 5b to the groove portion 5c. More specifically, the inner periphery of the leaf spring portion 6 is located inside the groove portion 5b. The outer periphery of the leaf spring portion 6 is located inside the groove portion 5c.

[0079] In this case, in a state where the thickness of the plate spring portion 6 is set to a desired thickness, the thickness of the portion of the plate spring portion 6 that protrudes from the rotor base portion 5 in the axial direction Z can be made thin. Alternatively, in a case where a dimension equivalent to the depth of the groove portion 5b and the groove portion 5c is a dimension equivalent to the thickness of the plate spring portion 6 or more, the plate spring portion 6 can be configured not to protrude from the rotor base portion 5 in the axial direction Z. Thus, the plate spring portion 6 is less likely to peel off from the rotor base portion 5.

[0080] In the present embodiment, the rotor base portion 5 having the groove portion 5b and the groove portion 5c is fitted to the plate spring portion 6. In this case, when the rotor 4 is formed, positioning of the plate spring portion 6 is easily performed. Thus, the rotor 4 can be efficiently obtained, and the productivity of the ultrasonic motor 1 can be effectively improved. Note that the groove portion 5b and the groove portion 5c can not necessarily be provided.

[0081] Figure 1 The ultrasonic motor 1 of the present embodiment shown is one example, and the structure of the ultrasonic motor 1 is not limited to the above-described structure. Similarly, the structure of the stator 2 is not limited to the above-described structure. The stator 2 can have only a proper vibration body 3 and a vibration generating element provided on the vibration body 3. In the rotor 4 of the present embodiment, the slide member 7 can be provided so as to contact the vibration body 3 of the stator 2.

[0082] Figure 6 is a schematic plan view of a rotor of a second embodiment of the present application. In Figure 6 In, a single-dot chain line indicates a circular orbit A.

[0083] The rotor 24 of the present embodiment differs from the rotor 4 of the first embodiment in that the rotor 24 has a plurality of slide members 27. The plurality of slide members 27 are dispersedly arranged in the circular orbit A in plan view. The rotor 24 of the present embodiment has the same structure as the rotor 4 of the first embodiment except for the above-described point.

[0084] In the present embodiment, the circular orbit A is a circular ring-shaped orbit. The circular orbit A corresponds to an orbit in a circumferential direction of a traveling wave that is generated in a stator used together with the rotor 24 for an ultrasonic motor. Thus, the plurality of slide members 27 are dispersedly arranged in the circumferential direction of the traveling wave.

[0085] By dispersively arranging the plurality of sliders 27 as described above, it is possible to reduce the rigidity of the circumferential direction of the traveling wave in the rotor 24. Thus, when a traveling wave is generated in a stator used with the rotor 24, it is possible to make the plate spring portion 6 easily and effectively follow the displacement of the vibration body of the stator. Thus, it is possible to make the portion of the wave crest in the vibration body and the portion around the same more reliably contact the sliders 27. Therefore, it is possible to increase the area of the portion of the large displacement in the vibration body that contacts the sliders 27 in the rotor 24. Thus, it is possible to increase the frictional force between the vibration body and the rotor 24, and to more reliably make the rotor 24 rotate efficiently.

[0086] Further, the plurality of sliders 27 are composed of carbon graphite. Thus, in the present embodiment, as in the first embodiment, it is possible to suppress the seizure.

[0087] It is preferable to arrange each of the sliders 27 so that the center of gravity of each of the sliders 27 is located on the annular track A. Thus, in the case where the rotor 24 is used for an ultrasonic motor, it is possible to more reliably and stably drive the ultrasonic motor. In addition, any portion of the slider 27 can be located on the annular track A. The center of gravity of the slider 27 can not necessarily be located on the annular track A.

[0088] As in the first embodiment, the width of the slider 27 is narrower than the width of the plate spring portion 6 and the width of the recess 5a of the rotor base portion 5. The width of the slider 27 in the present embodiment is the dimension of the slider 27 in the direction orthogonal to the annular track A in plan view.

[0089] Figure 7 is a schematic plan view of the rotor of the third embodiment. In Figure 7 In the drawing, hatching is added to indicate the protruding portions of the sliders described later.

[0090] The rotor 34 of the present embodiment differs from the rotor 4 of the first embodiment in that the sliders 37 have a plurality of protruding portions 37a. Except for the above point, the rotor 34 of the present embodiment has the same structure as the rotor 4 of the first embodiment.

[0091] The shape of the slider 37 in plan view is a circular ring shape. The plurality of protruding portions 37a of the slider 37 are dispersively arranged on the annular track. In other words, the plurality of protruding portions 37a are dispersively arranged in the circumferential direction of the traveling wave generated in a stator used with the rotor 34 for an ultrasonic motor. The plurality of protruding portions 37a protrude from the rotor main body 4A side toward the outside in the axial direction Z. Thus, the plurality of protruding portions 37a protrude toward the vibration body side of the above-described stator. The plurality of protruding portions 37a of the slider 37 contact the vibration body.

[0092] In the slide member 37, a plurality of protrusions 37a are connected to each other by portions other than the protrusions 37a. More specifically, the slide member 37 has a plurality of protrusions 37a and a plurality of 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 structure of the slide member 37 is a structure in which portions that contact the vibration body of the stator and portions that are thinner than the portions are alternately provided in the circumferential direction of the traveling wave generated in the stator used with the rotor 34. With this structure, it is possible to reduce the rigidity in the circumferential direction of the traveling wave in the rotor 34.

[0093] Thus, when a traveling wave is generated in the stator used with the rotor 34, it is possible to make the plate spring portion 6 easily and effectively follow the displacement of the vibration body of the stator. Thus, it is possible to make the portion of the wave crest in the vibration body when the traveling wave is generated and the portion around the portion more reliably contact the slide member 37. Therefore, it is possible to increase the area of the portion of the large displacement of the vibration body that contacts the slide member 37 of the rotor 34. Therefore, it is possible to increase the frictional force between the vibration body and the rotor 34, and it is possible to more reliably make the rotor 34 rotate efficiently.

[0094] The slide member 37 in the present embodiment corresponds to one member in which a plurality of slide members 27 are connected in the second embodiment. Specifically, the portions in the slide member 37 that correspond to the plurality of slide members 27 are the plurality of protrusions 37a. The slide member 37 is one member having the above-described structure, and thus the processing of the slide member 37 is easy, and the processing and assembly of the rotor 34 are easy. Thus, it is possible to improve the productivity of the rotor 34. Also, it is possible to improve the connection strength of the slide member 37 and the plate spring portion 6 of the rotor main body 4A.

[0095] The thickness of the portions other than the protrusions 37a in the slide member 37, that is, the thickness of the non-protrusions 37b, is preferably 70% or less, and more preferably 30% or less, of the thickness of the protrusions 37a. Thus, it is possible to more reliably reduce the rigidity in the circumferential direction of the traveling wave in the rotor 34.

[0096] Further, the slide member 37 is composed of carbon graphite. Thus, as in the first embodiment, it is possible to suppress the seizure.

[0097] In the slide member 37, the width of the protrusions 37a is the same as the width of the non-protrusions 37b. However, it is not limited thereto. For example, in the modification example of the third embodiment shown in FIG. 9, in the slide member 37A, the width of the non-protrusions 37b is wider than the width of the protrusions 37a. Since the width of the non-protrusions 37b is wide, it is possible to effectively improve the connection strength of the slide member 37A and the plate spring portion 6 of the rotor main body 4A. Figure 8

[0098] ​The sliding member 37A is made of carbon graphite. Thus, as with the third embodiment, seizure can be suppressed.

[0099] Figure 9 is a schematic cross-sectional view of a portion of the rotor of the fourth embodiment that corresponds to a cross section along the I-I line in Figure 3

[0100] The rotor 44 of the present embodiment differs from the rotor 4 of the first embodiment in that the rotor main body 44A is composed only of the rotor base portion and that 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 the present embodiment also differs from the rotor 4 of the first embodiment in that it has the soft resin layer 48. Further, the rotor 44 of the present embodiment also differs from the rotor 4 of the first embodiment in that the width of the sliding member 7 is the same as the width of the rotor main body 44A. Except for the above points, the rotor 44 of the present embodiment has the same structure as the rotor 4 of the first embodiment.

[0101] In the present 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 be 80% or less of the Young's modulus of the sliding member 7, or that the flexural modulus of the soft resin layer 48 be 80% or less of the flexural modulus of the sliding member 7.

[0102] The soft resin layer 48 can be, for example, an epoxy resin, a phenol resin, or a polyphenylene sulfide (PPS) resin, or the like. Alternatively, the soft resin layer 48 can be a resin layer in which the Young's modulus is adjusted to be 80% or less of the Young's modulus of the sliding member 7, or the flexural modulus is adjusted to be 80% or less of the flexural modulus of the sliding member 7, by adding an additive to an appropriate resin. Alternatively, the soft resin layer 48 can be a resin layer in which at least one of the Young's modulus and the flexural modulus is adjusted to be 7 GPa or less, by adding an additive to an appropriate resin.

[0103] The soft resin layer 48 is provided between the rotor main body 44A and the sliding member 7. That is, the rotor 44 has a structure in which the rotor main body 44A, the soft resin layer 48, and the sliding member 7 are stacked in this order.

[0104] More specifically, in the present embodiment, the entire portion of the sliding member 7 is provided on the soft resin layer 48. Alternatively, the sliding member 7 can include a portion that is not provided on the soft resin layer 48. The rotor 44 is used together with a stator having a vibrating body for an ultrasonic motor. The portion in which the sliding member 7 and the soft resin layer 48 are stacked can overlap, in plan view, with a portion of a wave crest in the vibrating body when a traveling wave is generated in the stator and a portion around the wave crest.

[0105] ​The soft resin layer 48 and the sliding member 7 can also be joined by another joining member such as an adhesive. Alternatively, the soft resin layer 48 can be a joining member that joins the rotor main body 44A and the sliding member 7.

[0106] As described above, the width of the sliding member 7 is the same as the width of the rotor main body 44A. However, for example, the width of the sliding member 7 can be narrower than the width of the rotor main body 44A.

[0107] Figure 10 is a schematic cross-sectional view of a rotor of the fourth embodiment. Figure 9 is a schematic cross-sectional view of a state in which the portion shown by the arrow contacts the vibration body of the stator and a state in which a traveling wave is generated in the stator.

[0108] In the present embodiment, a portion of the rotor 44 elastically deforms in accordance with the displacement of the vibration body 3 caused by the traveling wave. More specifically, the soft resin layer 48 elastically deforms. Along with this, as shown by the arrow in Figure 10 the sliding member 7 also deforms. Thereby, it is possible to bring the portion of the vibration body 3 in which a wave crest is generated when the traveling wave is generated and the portion around the same into contact with the sliding member 7. Therefore, it is possible to increase the area of the portion of the vibration body 3 in which a large displacement occurs in contact with the sliding member 7 of the rotor 44. Therefore, it is possible to increase the frictional force between the vibration body 3 and the rotor 44, and it is possible to more reliably and efficiently rotate the rotor 44.

[0109] The elastic deformation of the soft resin layer 48 occurs in accordance with the displacement of the vibration body 3 in the stator, and thereby the resonance state of the stator changes. Specifically, a portion of the energy of the vibration in the stator is converted into heat along with the elastic deformation of the soft resin layer 48. That is, the energy of the vibration in the stator is absorbed. Therefore, the mechanical quality factor Qm of the resonance state of the stator becomes small, and the amplitude of the vibration body 3 in the stator becomes small. In addition, the larger the amplitude of the vibration body 3, the more the maximum rotational speed of the ultrasonic motor increases. On the other hand, along with the elastic deformation of the soft resin layer 48, it is possible to obtain an effect in which the range of the frequency at which the stator becomes the resonance state becomes wide. This effect is called a damping effect.

[0110] By the damping effect, even in a case in which the vibration of the stator is deviated, it is possible to easily bring the stator into the resonance state. Therefore, even in a case in which the vibration of the stator is deviated, it is possible to appropriately rotate the rotor 44, and it is possible to appropriately drive the ultrasonic motor.

[0111] Furthermore, by the selection of the material of the soft resin layer 48 or the like, the Young's modulus or the flexural modulus of elasticity of the soft resin layer 48 is adjusted, and thereby it is possible to adjust the balance between the size of the amplitude of the vibration of the vibration body 3 and the width of the range of the frequency at which the stator becomes the resonance state. Alternatively, by adjusting the thickness of the soft resin layer 48 or the like, it is also possible to adjust the above-described balance.

[0112] Further, the sliding member 7 is made of carbon graphite. Thus, as in the first embodiment, seizure can be suppressed.

[0113] Further, in the case where the soft resin layer 48 is provided, the soft resin layer 48 can be provided Figure 4 between the plate spring portion 6 and the sliding member 7. For example, in the fourth embodiment shown in FIG. 6, the plate spring portion 6 is provided on the rotor base portion 5. The soft resin layer 48 is provided between the plate spring portion 6 and the sliding member 7. In other words, the plate spring portion 6, the soft resin layer 48, and the sliding member 7 are stacked in this order. Figure 11

[0114] All of the sliding member 7 overlaps the recess 5a of the rotor base portion 5 when viewed from above. The width of the sliding member 7 is narrower than the width of the plate spring portion 6 and the width of the recess 5a.

[0115] The rotor 54 is used for an ultrasonic motor together with a stator having a vibrating body. Following displacement of the vibrating body caused by a traveling wave, the plate spring portion 6 and the soft resin layer 48 elastically deform. Along with the elastic deformation of the soft resin layer 48, the sliding member 7 also elastically deforms. Thus, the portion of the vibrating body where a wave crest is generated when the traveling wave is generated and the portion around the same can be brought into contact with the sliding member 7 more reliably. Therefore, the area where the portion of the vibrating body where a large displacement is generated is in contact with the sliding member 7 of the rotor 54 can be increased more reliably. Thus, 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.

[0116] As in the fourth embodiment, even in the case where the vibration of the stator is deviated due to a damping effect, the rotor 54 can be rotated appropriately, and the ultrasonic motor can be driven appropriately. By adjusting the Young's modulus or the flexural modulus of the soft resin layer 48 through selection of the material of the soft resin layer 48 or the like, the balance between the amplitude of the vibration of the vibrating body of the stator and the width of the range of the frequency at which the stator becomes in a resonance state can also be adjusted. Alternatively, by adjusting the thickness of the soft resin layer 48 or the like, the above balance can also be adjusted.

[0117] Further, the absorption of the energy of the vibration in the stator also occurs along with the elastic deformation of the plate spring portion 6 following displacement of the vibrating body in the stator. By selecting the material of the plate spring portion 6, adjusting the thickness of the plate spring portion 6 or the width of the recess 5a of the rotor base portion 5, or the like, the degree of the elastic deformation of the plate spring portion 6 can be adjusted. Thus, the amount of the energy of the vibration in the stator absorbed along with the elastic deformation of the plate spring portion 6 can be adjusted.

[0118] In this modification, the sliding member 7 is also made of carbon graphite. Thus, as in the fourth embodiment, seizure can be suppressed.​

[0119] The rotor 54 can also have Figure 6 the plurality of sliding members 27 in the second embodiment shown or Figure 7 the sliding member 37 in the third embodiment shown instead of the sliding member 7. In these cases, it is possible to lower the rigidity of the circumferential direction of the traveling wave generated in the stator used with the rotor 54. Thus, as with the second embodiment, the third embodiment, it is possible to increase the frictional force between the vibration body of the stator and the rotor 54, and it is possible to rotate the rotor 54 more reliably and efficiently.

[0120] Likewise, the rotor 44 of the fourth embodiment can also have Figure 6 the plurality of sliding members 27 in the second embodiment shown or Figure 7 the sliding member 37 in the third embodiment shown instead of the sliding member 7. In these cases, it is possible to lower the rigidity of the circumferential direction of the traveling wave generated in the stator used with the rotor 44. Thus, as with the second embodiment, the third embodiment, it is possible to increase the frictional force between the vibration body of the stator and the rotor 44, and it is possible to rotate the rotor 44 more reliably and efficiently.

[0121] Figure 12 is a schematic bottom view of a stator of a fifth embodiment of the present application.

[0122] The stator 62 of the present embodiment differs from the stator 2 in the first embodiment in that it has the sliding member 7. Other than the above point, the stator 62 of the present embodiment has the same structure as the stator 2 of the first embodiment.

[0123] The second main surface 3b of the vibration body 3 in the stator 62 is provided with the sliding member 7. The sliding member 7 has the same structure as the sliding member 7 of the rotor 4 in the first embodiment. Specifically, the shape of the sliding member 7 in the present embodiment when viewed from above is a circular ring shape. The sliding member 7 is composed of carbon graphite.

[0124] The sliding member 7 is provided in a manner that surrounds the through-hole 3c of the vibration body 3 in the stator 62. The stator 62 is used with a rotor for an ultrasonic motor. The sliding member 7 in the stator 62 is a member that comes into contact with the rotor. The surface of the rotor slides on the sliding member 7 when the ultrasonic motor is driven. Therefore, the sliding member 7 in the stator 62 relatively slides on the surface of the rotor when the ultrasonic motor is driven.

[0125] The structure of the rotor used with the stator 62 is not particularly limited. As the material of the portion of the rotor that comes into contact with the sliding member 7, it is possible to use anything other than resin.

[0126] In driving the ultrasonic motor using the stator 62 of the present embodiment, even if abrasive powder is generated from the sliding member 7 composed of carbon graphite, a water-soluble component that functions as an adhesive is not generated. Therefore, even in an environment where humidity is high and the rotor and the stator 62 are exposed to moisture, it is difficult for the portion where the rotor and the stator 62 of the ultrasonic motor are in contact to be consolidated and the like. Thus, seizure can be suppressed. Thus, even in a severe environment where humidity is high, the ultrasonic motor can be appropriately used.

[0127] In addition, the stator 62 can have, for example, the plurality of sliding members 27 of the second embodiment shown in Figure 6 In addition, the stator 62 can have, for example, the plurality of sliding members 27 of the second embodiment shown in Figure 7 In addition, the stator 62 can have, for example, the plurality of sliding members 27 of the second embodiment shown in Figure 8 In addition, the stator 62 can have, for example, the plurality of sliding members 27 of the second embodiment shown in

[0128] Figure 13 is a schematic bottom view of the stator of the sixth embodiment. Figure 14 is a schematic cross-sectional view along the line II-II in Figure 13 In Figure 13 and Figure 14 , the piezoelectric elements are omitted.

[0129] As shown in Figure 13 and Figure 14 , the present embodiment differs from the fifth embodiment in that a plurality of protruding portions 73e are provided on the second main surface 73b of the vibrating body 73. The present embodiment also differs from the fifth embodiment in that a plurality of sliding members 27 are provided. Except for the above points, the stator 72 of the present embodiment has the same structure as the stator 62 of the fifth embodiment. Therefore, the vibrating body 73 has the first main surface 73a and the second main surface 73b, and the through-hole 73c is provided in the vibrating body 73.

[0130] In addition, as described above, in Figure 13 and Figure 14 , the piezoelectric elements are omitted. However, in the present embodiment, a plurality of piezoelectric elements are provided on the first main surface 73a of the vibrating body 73, as in the fifth embodiment.

[0131] On the second main surface 73b of the vibrating body 73, a plurality of protruding portions 73e are provided in a manner of surrounding the through-hole 73c. The plurality of protruding portions 73e are dispersedly arranged in a ring-shaped track. Specifically, the ring-shaped track is a circular ring-shaped track. In other words, the plurality of protruding portions 73e are dispersedly arranged in a circumferential direction of the traveling wave generated in the stator 72.

[0132] The plurality of protrusions 73e protrude from the second main surface 73b of the vibrating body 73 toward the outside in the axial direction Z. When the stator 72 is used with the rotor for the ultrasonic motor, the plurality of protrusions 73e protrude toward the rotor side.

[0133] One sliding member 27 is provided on each of the plurality of protrusions 73e. Therefore, the plurality of sliding members 27 are dispersedly arranged along the circumferential direction of the traveling wave generated in the stator 72, like the plurality of protrusions 73e. The plurality of sliding members 27 are in contact with the rotor.

[0134] The plurality of sliding members 27 are composed of carbon graphite. Thus, in the present embodiment, like the fifth embodiment, seizure can be suppressed.

[0135] Further, in the present embodiment, the plurality of protrusions 73e protrude from the second main surface 73b toward the outside in the axial direction Z. Thus, when the traveling wave is generated in the vibrating body 73 of the stator 72, the tip portions of the plurality of protrusions 73e are displaced further more largely. Further, the rotor is in contact with the sliding members 27 provided on the surface of the tip portions of the protrusions 73e in the second main surface 73b. Therefore, by the traveling wave generated in the stator 72, the rotor can be rotated efficiently.

[0136] Specifically, the displacement of the traveling wave generated in the stator 72 is displacement caused by the flexural deformation of the vibrating body 73. The displacement caused by the flexural deformation is displacement in the direction parallel to the axial direction Z. Therefore, when the traveling wave is generated, the flexural deformation is generated in the first main surface 73a and the second main surface 73b of the vibrating body 73. As described above, the tip portions of the plurality of protrusions 73e provided in the second main surface 73b are displaced further more largely.

[0137] However, it is difficult to generate the flexural deformation on the surface of the tip portions of the protrusions 73e where each of the sliding members 27 is provided. Therefore, it is also difficult to generate the flexural deformation in each of the sliding members 27. Thus, the loss of the energy of the stator 72 accompanying the flexural deformation of the plurality of sliding members 27 is reduced. Thus, the ultrasonic motor can be driven efficiently.

[0138] Further, in each of the sliding members 27 composed of carbon graphite, a crack can be generated accompanying excessive flexural deformation. In contrast, in the present embodiment, it is difficult to generate the flexural deformation in each of the sliding members 27. Therefore, the crack of each of the sliding members 27 can be further reliably suppressed.

[0139] The ultrasonic motor of the present application can be, for example, only with the rotor of the present application and a proper stator. Or, the ultrasonic motor of the present application can be only with a proper rotor and the stator of the present application. Thus, seizure can be suppressed.

[0140] Hereinafter, examples of a manner in which a rotor, a stator, and an ultrasonic motor according to the present application are described are summarized.

[0141] <1> A rotor, wherein the rotor is used for an ultrasonic motor provided with a stator, the stator having a vibration body and a vibration generating element provided on the vibration body, the rotor comprising: a rotor main body; and a sliding member provided on the rotor main body and in contact with the vibration body, the sliding member being composed of a carbon graphite quality.

[0142] <2> The rotor according to <1>, wherein, when a peak value of a D band is set as D, a peak value of a G band is set as G, and a graphitization degree of the carbon graphite quality is set as R in a Raman spectrum of the carbon graphite quality for the sliding member obtained by a Raman spectroscopy analysis method in which a wavelength of incident laser light is set as 532 nm and a kind of grating is set as 600 gr / m, R = D / G, and the graphitization degree R of the carbon graphite quality is 0.5 or more and 1.2 or less.

[0143] <3> The rotor according to <1> or <2>, wherein the rotor main body has a rotor base portion having a recess, and a plate spring portion provided on the rotor base portion in a manner of covering the recess, the sliding member being provided on the plate spring portion.

[0144] <4> The rotor according to <3>, further comprising a soft resin layer provided between the plate spring portion and the sliding member.

[0145] <5> The rotor according to <1> or <2>, further comprising a soft resin layer provided between the rotor main body and the sliding member.

[0146] <6> The rotor according to any one of <1> to <5>, comprising a plurality of the sliding members.

[0147] The plurality of sliding members are dispersedly arranged in a ring-shaped track in plan view.

[0148] <7> The rotor according to any one of <1> to <5>, wherein the sliding member includes a plurality of protrusions dispersedly arranged in a ring-shaped track in plan view, the plurality of protrusions protruding toward the vibration body side.

[0149] <8> A stator, wherein the rotor is used for an ultrasonic motor provided with a rotor, the stator comprising: a vibration body; a vibration generating element provided on the vibration body; and a sliding member provided on the vibration body and in contact with the rotor, the sliding member being composed of a carbon graphite quality.

[0150] <9> The rotor according to <8>, wherein, when a peak value of a D band is set to D, a peak value of a G band is set to G, and a graphitization degree of the carbon graphite quality is set to R in a Raman spectrum of the carbon graphite quality for the slider obtained by a Raman spectroscopy method with a wavelength of incident laser light set to 532 nm and a kind of grating set to 600 gr / m, R = D / G, and the graphitization degree R of the carbon graphite quality is 0.5 or more and 1.2 or less.

[0151] <10> An ultrasonic motor, wherein the ultrasonic motor comprises: the ultrasonic rotor according to any one of <1> to <7>; and a stator having the vibration body and the vibration generating element provided on the vibration body.

[0152] <11> An ultrasonic motor, wherein the ultrasonic motor comprises: the stator according to <8> or <9>; and the rotor.

[0153] [Legend]

[0154] 1, ultrasonic motor; 2, stator; 3, vibration body; 3a, 3b, first main surface, second main surface; 3c, through hole; 3d, contact surface; 4, rotor; 4A, rotor main body; 4c, through hole; 5, rotor base portion; 5a, recessed portion; 5b, 5c, groove portion; 6, plate spring portion; 6a, 6b, first surface, second surface; 7, slider; 8, first housing member; 8a, 8b, first cylindrical protrusion, second cylindrical protrusion; 8c, through hole; 9, second housing member; 9a, cylindrical protrusion; 9c, through hole; 10, shaft member; 10a, wide portion; 12, elastic member; 13, piezoelectric element; 14, piezoelectric body; 14a, 14b, third main surface, fourth main surface; 15A, 15B, first electrode, second electrode; 16, spring member; 16c, through hole; 17, retainer; 18, 19, first bearing portion, second bearing portion; 24, rotor; 27, slider; 34, rotor; 37, 37A, slider; 37a, protrusion portion; 37b, non-protrusion portion; 44, rotor; 44A, rotor main body; 48, soft resin layer; 54, rotor; 62, 72, stator; 73, vibration body; 73a, 73b, first main surface, second main surface; 73c, through hole; 73e, protrusion portion.

Claims

1. A rotor, wherein, This rotor is used in an ultrasonic motor having a stator, the stator having a vibrating body and a vibration generating element disposed on the vibrating body. The rotor includes: Rotor body; and A sliding element, which is disposed on the rotor body and in contact with the vibrating body, The slider is made of carbon graphite.

2. The rotor according to claim 1, wherein, When the Raman spectrum of the carbon-graphite material used in the sliding member is obtained by Raman spectroscopy with the incident laser wavelength set to 532 nm and the grating type set to 600 gr / m, and the peak value of the D band is set to D, the peak value of the G band is set to G, and the graphitization degree of the carbon-graphite material is set to R, then R = D / G. The degree of graphitization R of the carbon-graphite is 0.5 or higher and 1.2 or lower.

3. The rotor according to claim 1 or 2, wherein, The rotor body has: The rotor base portion has a recess; and A leaf spring portion is provided on the rotor base portion in a manner that covers the recess. The sliding member is provided on the leaf spring portion.

4. The rotor according to claim 3, wherein, The rotor also includes a soft resin layer disposed between the leaf spring portion and the sliding member.

5. The rotor according to claim 1 or 2, wherein, The rotor also includes a soft resin layer disposed between the rotor body and the sliding member.

6. The rotor according to any one of claims 1 to 5, wherein, The rotor has a plurality of the aforementioned sliding elements. The plurality of sliders are distributed on a ring-shaped track when viewed from above.

7. The rotor according to any one of claims 1 to 5, wherein, The slider includes a plurality of protrusions distributed in a ring-shaped track when viewed from above, the plurality of protrusions projecting toward the vibrating body.

8. A stator, wherein, This stator is used in ultrasonic motors with rotors. The stator comprises: Vibrating body; and A vibration generating element is disposed on the vibrating body; A sliding element, which is disposed on the vibrating body and in contact with the rotor, The slider is made of carbon graphite.

9. The stator according to claim 8, wherein, When the Raman spectrum of the carbon-graphite material used in the sliding member is obtained by Raman spectroscopy with the incident laser wavelength set to 532 nm and the grating type set to 600 gr / m, and the peak value of the D band is set to D, the peak value of the G band is set to G, and the graphitization degree of the carbon-graphite material is set to R, then R = D / G. The degree of graphitization R of the carbon-graphite is 0.5 or higher and 1.2 or lower.

10. An ultrasonic motor, wherein, The ultrasonic motor comprises: a rotor as described in any one of claims 1 to 7, and The stator has the vibrating body and the vibration generating element disposed on the vibrating body.

11. An ultrasonic motor, wherein, The ultrasonic motor comprises the stator as described in claim 8 or 9; and The rotor.

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