JP2012227997A - Vibratory drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the maximum rotational speed by imparting a shape of suppressing generation of crack to an elastic body in a vibratory drive unit.SOLUTION: The vibratory drive unit has a vibrator configured of an elastic body 7 and an electromechanical energy conversion element which excites the elastic body to vibrate, and a rotor which rotates by friction with the elastic body. The elastic body is provided, at a portion in the axial direction becoming a node of vibration, with a recess 7e opening toward the radial outside of the elastic body and extending in the circumferential direction thereof. Two faces 7e1, 7e2 of the recess provided on the sides facing each other in the axial direction are inclining in the radial direction so as to approach each other in the axial direction toward the inner peripheral side, and a concave face 7e3 is formed between the two faces at a part of the recess on the inner peripheral side.

Description

  The present invention relates to a vibration type driving device called a vibration wave motor or the like that obtains a driving force using vibration excited by an electromechanical energy conversion element.

  Such a vibration type driving device is disclosed in, for example, Patent Document 1. The vibration type driving device includes an elastic body, a vibrator configured by an electro-mechanical energy conversion element that excites vibration in the elastic body, and a rotor that rotates by friction between the vibrating elastic body.

  FIG. 9 shows a configuration of a conventional general vibration type driving device. In this figure, the direction in which the rotation center axes of the rotors 16a and 16b extend is referred to as the axial direction. FIG. 10 shows a partial cross section of the elastic body 107 used in the vibration type driving device shown in FIG. The elastic body 107 has vibration portions 107a and 107b on both sides in the axial direction, and piezoelectric element holding portions 107c and 107d between the vibration portions 107a and 107b. In this elastic body 107, the first elastic body having the vibrating portion 107a and the piezoelectric element holding portion 107c and the second elastic body having the vibrating portion 107b and the piezoelectric element holding portion 107d are joined on the piezoelectric element holding portion side. Have been integrated.

  A piezoelectric element 9 serving as an electro-mechanical energy conversion element is sandwiched and held between the two piezoelectric element holding portions 107c and 107d. Two frequency signals having different phases are input to the piezoelectric element 9 through the flexible substrate 8. In the piezoelectric element 9 to which two frequency signals are input, a portion extending in the axial direction and a portion compressing are generated in the circumferential direction, and these portions sequentially move in the circumferential direction. As a result, the elastic body 107 is excited to vibrate such that it bends with respect to the axial direction and the direction of the bending sequentially changes in the circumferential direction.

  A recess 107e extending in the circumferential direction of the elastic body 107 is formed between the vibration section 107a and the piezoelectric element holding section 107c and between the vibration section 107b and the piezoelectric element holding section 107d in the elastic body 107. The concave portion 107e has a rectangular shape in a cross section perpendicular to the circumferential direction of the elastic body (cross section along the axial direction), and opens toward the radially outer side of the elastic body 107. The portion of the elastic body 107 where the concave portion 107e is formed is less rigid than the other portions. The recess 107e is formed at a position that becomes a node of vibration excited by the elastic body 107. As a result, the amplitude of the vibrating portions 107a and 107b is increased as compared with the case where the concave portion 107e is not formed.

  The vibrator 27 including the elastic body 107 and the piezoelectric element 9 is fixed to a case (not shown) by the support member 10.

  Each of the rotors 16a and 16b includes a turntable 12a and 12b and sliding members 11a and 11b fixed to the turntables 12a and 12b. The sliding members 11a and 11b are brought into pressure contact with the vibrating portions 107a and 107b of the vibrator 27 by the rotary disks 12a and 12b receiving axial biasing forces from the pressure springs 13a and 13b, respectively. The rotors 16a and 16b are rotated by the contact friction between the vibrating portions 107a and 107b and the sliding members 11a and 11b, and the output shaft 1 that rotates integrally with the rotary plates 12a and 12b is rotated. A driving force can be extracted from the output shaft 1 by a gear or the like.

  FIG. 11 shows the relationship between the frequency (Hz) of the frequency signal applied to the piezoelectric element 9 of the vibration type driving apparatus configured as described above and the rotation speed (r / min) of the vibration type driving apparatus. The maximum value of the rotational speed of the vibration type driving device corresponds to the resonance frequency of the vibrator. The frequency of the frequency signal that is actually applied to the piezoelectric element is set in a frequency range corresponding to a rotational speed range higher than the resonance frequency. When the frequency is lowered (closer to the resonant frequency), the rotational speed increases and the frequency is increased. Increasing the value (away from the resonance frequency) decreases the rotational speed.

JP 2003-23780 A

  However, the maximum rotational speed of the vibration type driving device is limited by the mechanical characteristics of the elastic body 107. That is, when the rotational speed exceeds the limit rotational speed shown in FIG. 11, as shown in FIG. 10, cracks C may occur at the corners of the deepest part (innermost peripheral part) of each recess 107e in the elastic body 107. There is. For this reason, the maximum rotational speed is limited so that the rotational speed does not exceed the limit rotational speed.

  Therefore, if the occurrence of the crack C as described above in the elastic body 107 can be suppressed, the maximum rotational speed of the motor can be set higher.

  The present invention provides a vibration type driving device in which the maximum rotational speed can be further increased by giving the elastic body a shape capable of suppressing the occurrence of cracks.

  A vibration type driving device according to one aspect of the present invention includes an oscillator configured by an elastic body and an electro-mechanical energy conversion element that excites vibration in the elastic body, and a rotor that rotates by friction with the elastic body. Have. A portion of the elastic body in the axial direction that serves as a vibration node has a recess that opens outward in the radial direction of the elastic body and extends in the circumferential direction of the elastic body. The two surfaces of the recesses provided on the sides facing each other in the axial direction are inclined with respect to the radial direction so as to approach each other in the axial direction toward the inner peripheral side, A concave curved surface is formed between the two surfaces in the peripheral portion.

  According to another aspect of the present invention, there is provided a vibration type driving apparatus that rotates due to friction between an elastic body and a vibrator that includes an electromechanical energy conversion element that excites vibration in the elastic body and the elastic body. With a rotor. A portion of the elastic body in the axial direction that serves as a vibration node has a recess that opens outward in the radial direction of the elastic body and extends in the circumferential direction of the elastic body. And two surfaces provided on the sides facing each other in the axial direction of the concave portion extend in parallel to the radial direction, and a concave curved surface is provided between the two surfaces in the inner peripheral side portion of the concave portion. Is formed.

  In addition, the apparatus which has the said vibration type drive device and the driven member driven by this also comprises the other one side of this invention.

  According to the present invention, it is possible to suppress the occurrence of cracks in the elastic body by forming the concave portion provided in the elastic body to increase the amplitude of vibration in the shape as described above. The maximum rotation speed can be increased. By using such a vibration type driving device, it is possible to realize a device that is less prone to malfunction due to the occurrence of cracks in the elastic body and that can drive the driven member at a higher speed.

1 is a cross-sectional view showing an overall configuration of a vibration type driving apparatus that is Embodiment 1 of the present invention. Sectional drawing and the partial expanded sectional view which show the shape of the elastic body used for the vibration type drive device of Example 1. FIG. Sectional drawing and the partial expanded sectional view which show the shape of the elastic body used for the vibration type drive device which is Example 2 of this invention. The figure which shows the stress distribution in the elastic body of Example 1,2. FIG. 9 is a partially enlarged cross-sectional view showing a modification (Example 3) of the elastic body described in Examples 1 and 2. FIG. 6 is a partially enlarged cross-sectional view showing the shape of an elastic body used in a vibration type driving apparatus that is Embodiment 4 of the present invention. The figure which shows the manufacturing method of the elastic body in Example 5 of this invention. Sectional drawing and the partial expanded sectional view which show the shape of the elastic body used for the vibration type drive device which is Example 6 of this invention. Sectional drawing which shows the whole structure of the conventional vibration type drive device. Sectional drawing of the elastic body used for the conventional vibration type drive device. The figure which shows the relationship between the frequency of the frequency signal in the conventional vibration type drive device, and rotation speed. FIG. 3 is a schematic diagram illustrating vibration of an elastic body in Example 1.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of a vibration type driving apparatus that is Embodiment 1 of the present invention. In this figure, the direction in which the rotation center axes of the rotors 16a and 16b extend is referred to as the axial direction. The basic configuration of the vibration type driving device is the same as that of the conventional vibration type driving device shown in FIG. FIG. 2 shows a partial cross section of the elastic body 7 used in the vibration type driving apparatus shown in FIG.

  The elastic body 7 has vibration portions 7a and 7b on both sides in the axial direction, and piezoelectric element holding portions 7c and 7d between the vibration portions 7a and 7b. In this elastic body 7, the first elastic body having the vibration part 7a and the piezoelectric element holding part 7c and the second elastic body having the vibration part 7b and the piezoelectric element holding part 7d are joined on the piezoelectric element holding part side. Have been integrated.

  A piezoelectric element 9 as an electro-mechanical energy conversion element is sandwiched and held between the two piezoelectric element holding portions 7c and 7d. Two frequency signals having different phases are input to the piezoelectric element 9 via the flexible substrate 8. In the piezoelectric element 9 to which two frequency signals are input, a portion extending in the axial direction and a portion compressing are generated in the circumferential direction, and these portions sequentially move in the circumferential direction. As a result, the elastic body 7 is excited to vibrate such that it bends with respect to the axial direction and the direction of the bending sequentially changes in the circumferential direction.

  A recess 7e extending in the circumferential direction of the elastic body 7 is formed between the vibration part 7a and the piezoelectric element holding part 7c and between the vibration part 7b and the piezoelectric element holding part 7d in the elastic body 7. The recess 7 e opens toward the radially outer side of the elastic body 7. The portion of the elastic body 7 where the recess 7e is formed has lower rigidity than the other portions. The recess 7e is formed at a position that becomes a node of vibration excited by the elastic body 7. As a result, the amplitudes of the vibrating portions 7a and 7b are enlarged as compared with the case where the concave portion 7e is not formed.

  FIG. 12 shows a state where the elastic body 7 (first elastic body) is bent by vibration. The vibration part 7a is largely bent with respect to the piezoelectric element holding part 7c with the vicinity of the recess 7e in the elastic body 7 as the center (node).

  The vibrator 17 composed of the elastic body 7 and the piezoelectric element 9 is fixed to a case (not shown) by the support member 10.

  Each of the rotors 16a and 16b includes a turntable 12a and 12b and sliding members 11a and 11b fixed to the turntables 12a and 12b. The turntables 12a and 12b are engaged with the rotation engagement members 14a and 14b fixed to the output shaft 1 in the circumferential direction, whereby the turntables 12a and 12b and the rotation engagement members 14a and 14b are output. The shaft 1 rotates as a unit. The output shaft 1 is rotatably supported by bearings (not shown) attached to both sides in the axial direction of the case.

  The rotary members 12a and 12b receive axial biasing forces from the pressure springs 13a and 13b, respectively, so that the sliding members 11a and 11b are pressed against the vibrating portions 7a and 7b of the vibrator 17. The rotors 16a and 16b are rotationally driven by the contact friction between the vibrating vibration parts 7a and 7b and the sliding members 11a and 11b, and the output shaft 1 is rotated through the rotating disks 12a and 12b and the rotation engaging members 14a and 14b. To do. A driving force can be extracted from the output shaft 1 by a gear or the like, and the driven member 30 such as a gear, a pulley, a lever, an arm, or a shaft can be driven using the driving force. The driven member 30 is a component of various devices including a vibration type driving device as a driving source.

  The relationship between the frequency (Hz) of the frequency signal applied to the piezoelectric element 9 of the vibration type driving device configured as described above and the rotation speed (r / min) of the vibration type driving device is shown in FIG. This is basically the same as the relationship in the vibration type driving device. However, in this embodiment, in order to make the maximum rotational speed higher than the conventional one, the shape of the recess 7e is characterized as described below.

  Conventionally, as shown in FIG. 10, the concave portion 107e provided in the elastic body 107 has a rectangular shape in a cross section perpendicular to the circumferential direction (a cross section along the axial direction, hereinafter referred to as a circumferential cross section). However, cracks due to stress concentration were likely to occur at the corners.

  On the other hand, in the present embodiment, in the circumferential cross section, two surfaces (indicated by reference numerals 7e1 and 7e2 in FIG. 1A) provided on the side of the recess 7e facing each other in the axial direction are It inclines with respect to radial direction so that it may mutually approach in an axial direction toward an inner peripheral side. In other words, the two surfaces (hereinafter, referred to as the upper inclined surface 7e1 and the lower inclined surface 7e2) are formed like a truncated cone surface with the top surfaces approaching each other in the axial direction.

  Further, as shown in an enlarged view in FIG. 1B, the inner peripheral side portion of the concave portion 7e has a concave shape toward the radially outer side, and the inner portion of the upper inclined surface 7e1 and the lower inclined surface 7e2. A concave curved surface 7e3 connected to the peripheral end without a step is formed. That is, between the two frustums (upper inclined surface 7e1 and lower inclined surface 7e2), there is provided an inner peripheral end portion formed by a concave curved surface 7e3 smoothly connected to them (so that no corner portion is formed). .

  By forming the inner surface of the recess 7e in this way, the stress around the recess 7e in the vibrating elastic body 7 is smoothly changed along the recess 7e as shown in FIG. Generation of cracks can be suppressed. For this reason, the maximum number of rotations of the vibration type driving device can be made higher than in the prior art.

  By using such a vibration-type drive device as a drive source for the driven member 30 in various devices, it is difficult to cause malfunction due to the occurrence of cracks in the elastic body, and the driven member can be driven at a higher speed. Equipment can be realized.

  The inclined surfaces (7e1, 7e2) may be surfaces having a curvature in the circumferential cross section (for example, convex surfaces).

  FIG. 3A shows the shape of the circumferential cross section of an elastic body (first and second elastic bodies) 7 ′ used in the vibration type driving apparatus that is Embodiment 2 of the present invention.

  Also in the elastic body 7 ′ of the present embodiment, as in the first embodiment, two surfaces (upper inclined surface 7e1 and upper inclined surface 7e1) provided on the inner surface of the recess 7e on the sides facing each other in the axial direction in the circumferential section The lower inclined surfaces 7e2) are inclined with respect to the radial direction so as to approach each other in the axial direction toward the inner peripheral side. That is, the upper inclined surface 7e1 and the lower inclined surface 7e2 are formed like a truncated cone having the top surfaces close to each other in the axial direction.

  In this embodiment, the upper and lower portions of the inner peripheral side of the recess 7e have a concave shape toward the radially outer side as shown in an enlarged view in FIG. 3B, and the upper inclined surface 7e1. And two concave curved surfaces 7e3 and 7e3 'connected to the inner peripheral ends of the lower inclined surface 7e2 without a step.

  Further, between the two concave curved surfaces 7e3 and 7e3 ', an inner peripheral groove portion 7e4 that is recessed toward the inner peripheral side (opens toward the outer peripheral side) and extends in the circumferential direction is formed. That is, the concave curved surfaces 7e3, 7e3 ′ and the concave curved surfaces 7e3, 7e3 ′ smoothly connected to the two conical surfaces (the upper inclined surface 7e1 and the lower inclined surface 7e2) (so that corners are not formed) are connected. An inner peripheral end portion having an inner peripheral groove portion 7e4 provided therebetween is provided. The inner circumferential groove 7e4 has a rectangular circumferential cross section.

No corners are formed from the upper inclined surface 7e1 and the lower inclined surface 7e2 to the concave curved surfaces 7e3, 7e3 '. In addition, since the corners are formed between the concave curved surfaces 7e3, 7e3 'and the inner peripheral groove 7e4, the stress around the periphery is dispersed. Thereby, it is possible to suppress the occurrence of stress concentration around the recess 7e in the vibrating elastic body 7, that is, the generation of cracks. FIG. 4A shows the recess in the elastic body 7 described in the first embodiment. The stress distribution around 7e is shown. Also in Example 1, the stress S is dispersed to some extent, and no stress concentration occurs.

  On the other hand, FIG. 4B shows the stress distribution around the recess 7e in the elastic body 7 ′ described in the second embodiment. In the second embodiment, the stress S is further dispersed as compared with the first embodiment, and the occurrence of stress concentration is more effectively suppressed.

  5A to 5C show a modified example of the elastic bodies 7 and 7 'in the above-described first and second embodiments as a third embodiment. In these modified examples, similarly to the first and second embodiments, the recess 7e is two surfaces provided on the sides facing each other in the axial direction, and approaches each other in the axial direction toward the inner peripheral side. Thus, the upper inclined surface 7e1 and the lower inclined surface 7e2 are inclined with respect to the radial direction. That is, the upper inclined surface 7e1 and the lower inclined surface 7e2 are formed like a truncated cone having the top surfaces close to each other in the axial direction.

  In the modification shown in FIG. 5A, as in the second embodiment, a concave shape is formed outward in the radial direction, and a step is formed at each inner peripheral end of the upper inclined surface 7e1 and the lower inclined surface 7e2. Two concave curved surfaces 7e3 and 7e3 'that are connected to each other are formed. Further, between the two concave curved surfaces 7e3 and 7e3 ', an inner peripheral groove portion 7e5 is formed which is recessed on the inner peripheral side (opens on the outer peripheral side) and extends in the circumferential direction. That is, between the two conical surfaces (upper inclined surface 7e1 and lower inclined surface 7e2), the concave curved surfaces 7e3, 7e3 'smoothly connected to them (so that corners are not formed), and the concave curved surfaces 7e3, 7e3' An inner peripheral end portion having an inner peripheral groove portion 7e5 formed therebetween is provided.

  The inner circumferential groove portion 7e5 is opposed to each other in the axial direction on the inner circumferential side of the two parallel surfaces and two parallel surfaces extending in parallel in the radial direction near the opening of the inner circumferential groove portion 7e5. And two inclined surfaces that are inclined with respect to the radial direction so as to approach each other in the axial direction toward the inner peripheral side. That is, the two inclined surfaces are formed like a truncated cone having a top surface close to each other in the axial direction. These conical surfaces are in contact with each other at an angle of 90 degrees or smaller at the inner peripheral end thereof. As a result, the number of corners formed by the inner circumferential recess 7e5 is increased as compared with the second embodiment, and the stress dispersion is further promoted.

  In the modification shown in FIG. 5B, two concave curved surfaces 7e6 that have a concave shape toward the radially outer side and are connected to the inner peripheral ends of the upper inclined surface 7e1 and the lower inclined surface 7e2 without a step. , 7e7 are formed. These two concave curved surfaces 7e6 and 7e7 are adjacent to each other in the axial direction so that a ridge line extending in the circumferential direction is formed between them. As described above, a plurality of concave curved surfaces may be provided adjacent to each other on the inner peripheral side of the concave portion 7e so as to form a ridge line. In the present embodiment, compared to the first embodiment, the number of corner portions (ridge lines) formed in the inner peripheral side portion of the concave portion 7e is increased to further promote stress dispersion.

  Further, in the modification shown in FIG. 5C, as in the first embodiment, a concave curved surface 7e3 is formed between the upper inclined surface 7e1 and the lower inclined surface 7e2, but these upper inclined surface 7e1 and lower The inclined surface 7e2 and the inner peripheral recess 7e3 are provided with roughness due to unevenness. In the present embodiment, compared to the first embodiment, the number of corners (unevenness) formed in the inner peripheral side portion of the recess 7e is increased to further promote the stress dispersion.

  These modifications can also suppress the occurrence of stress concentration around the recess 7e in the vibrating elastic body, that is, the occurrence of cracks. For this reason, the maximum number of rotations of the vibration type driving device can be made higher than in the prior art.

  The roughness due to the unevenness shown in FIG. 5 (C) may be applied to the elastic bodies 7 and 7 ′ shown in FIG. 3 (Example 2) and FIGS. 5 (A) and 5 (B).

  In FIG. 6, the recessed part 7e of the elastic body used for the vibration type drive device which is Example 4 of this invention is expanded and shown. Also in the present embodiment, as in the first to third embodiments, two surfaces (an upper inclined surface 7e1 and a lower inclined surface) provided on the inner surface of the recess 7e on the sides facing each other in the axial direction in the circumferential cross section. 7e2) are inclined with respect to the radial direction so as to approach each other in the axial direction toward the inner peripheral side. That is, the upper inclined surface 7e1 and the lower inclined surface 7e2 are formed like a truncated cone having the top surfaces close to each other in the axial direction.

  In the present embodiment, the outer peripheral portion from the inner peripheral side of the concave portion 7e to the inner peripheral portion of the concave portion 7e (the portion from the innermost peripheral portion to the vicinity of the inner peripheral ends of the upper inclined surface 7e1 and the lower inclined surface 7e2) A plurality of concave curved surfaces 7e8 are formed toward the side. The radius of curvature of the plurality of concave curved surfaces 7e8 increases from the inner peripheral side to the outer peripheral side of the concave portion 7e. Each concave curved surface 7e8 is formed as a curved surface that becomes concave toward the radially outer side of the elastic body, and extends in the circumferential direction. A ridge line extending in the circumferential direction is formed between the curved surfaces 7e8 adjacent to each other.

  In this way, by forming the plurality of concave curved surfaces 7e8 having a radius of curvature that increases with distance from the innermost peripheral portion of the concave portion 7e, stress can be efficiently dispersed around the concave portion 7e. Occurrence of stress concentration around the periphery, that is, occurrence of cracks can be suppressed.

  The plurality of concave curved surfaces 7e8 on the upper inclined surface 7e1 and the lower inclined surface 7e2 described in the present embodiment are replaced with the elastic bodies 7 of the second and third embodiments shown in FIGS. 3 and 5A to 5C. , 7 '.

  FIG. 7 shows an example of a method for forming the recess 7e in the elastic body described in the first to fourth examples as the fifth example. In FIG. 7, the elastic body demonstrated in Example 1 is shown as a representative.

  Reference numeral 20 denotes a cutting tool 20 attached to a lathe. The elastic body is held and rotated by the chuck of the lathe, and the chuck is moved in the axial direction. Then, the upper inclined surface 7e1, the lower inclined surface 7e2, and the concave curved surface 7e3 of the recess 7e can be formed by cutting the elastic body while moving the nose R of the cutting tool 20 in the radial direction.

  Furthermore, the concave portions of the elastic bodies of Examples 2, 3, and 4 can be formed in the same manner by changing the shape of the cutting tool 20 and the nose radius.

  Moreover, the recessed part 7e of the elastic body of Examples 1-4 can also be formed using not only a lathe but working machines, such as a milling machine and a grinding machine.

  FIGS. 8A to 8C show an elastic body 7 ″ used for the vibration type driving apparatus which is Embodiment 6 of the present invention.

  Unlike the first to third embodiments, the recess 7e provided in the elastic body 7 ″ has an upper surface 7e1 ″ and a lower surface 7e2 ″ that face each other in the axial direction and extend in parallel to the radial direction. Between the upper surface 7e1 ″ and the lower surface 7e2 ″ in the inner peripheral side portion of the recess 7e, there is a concave shape toward the radially outer side, and a step is formed at each inner peripheral end of the upper surface 7e1 ″ and the lower surface 7e2 ″. Two concave curved surfaces 7e3 and 7e3 'that are connected to each other are formed.

  Further, between the two concave curved surfaces 7e3 and 7e3 ′, the inner peripheral groove portion 7e4 described in the second embodiment or the inner peripheral groove portion 7e5 described in the third embodiment is formed.

  Thus, even if the upper surface 7e1 ″ and the lower surface 7e2 ″ of the concave portion 7e are not conical, the concave curved surfaces 7e3, 7e3 ′ and the inner peripheral groove portions 7e4, 7e5 are formed on the inner peripheral side portion of the concave portion 7e. Compared with the case where these are not formed, it is possible to suppress the occurrence of stress concentration around the recess 7e to some extent.

  As shown in FIG. 2 (Embodiment 1), the inner circumferential groove portions 7e4 and 7e5 are not formed between the upper surface 7e1 ″ and the lower surface 7e2 ″ in the inner circumferential side portion of the recess 7e in this embodiment. Only the concave curved surface 7e3 may be formed, or only two concave curved surfaces 7e6 and 7e7 may be formed as shown in FIG. 5B (Example 3).

  Further, the upper surface 7e1, the lower surface 7e2 and the concave curved surface 7e3 (7e3 ', 7e6, 7e7) in this example are roughened by the unevenness described in FIG. 5C (Example 3) and FIG. 6 (Example 4). A plurality of concave curved surfaces having a radius of curvature that increases from the inner peripheral side toward the outer peripheral side may be formed.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

  It is possible to provide a vibration type driving device having a high maximum rotational speed.

DESCRIPTION OF SYMBOLS 1 Output shaft 4 Bearing 7,7 ', 7 "Elastic body 7e Recessed part 9 Piezoelectric element 10 Support member 11 Sliding member 12 Rotary disk 13 Pressure springs 16a and 16b Rotor 17 Vibrator 20 Byte

Claims (7)

A vibration type driving device having an elastic body and a vibrator constituted by an electro-mechanical energy conversion element that excites vibration in the elastic body, and a rotor that rotates by friction with the elastic body,
The elastic body has a concave portion extending in a radial direction of the elastic body and opened in a radial direction of the elastic body in a portion in an axial direction serving as the vibration node.
Two surfaces provided on the opposite sides of the recess in the axial direction are inclined with respect to the radial direction so as to approach each other in the axial direction toward the inner peripheral side,
In addition, the vibration type driving device is characterized in that a concave curved surface is formed between the two surfaces in the inner peripheral portion of the concave portion. A vibration type driving device having an elastic body and a vibrator constituted by an electro-mechanical energy conversion element that excites vibration in the elastic body, and a rotor that rotates by friction with the elastic body,
The elastic body has a concave portion extending in a radial direction of the elastic body and opened in a radial direction of the elastic body in a portion in an axial direction serving as the vibration node.
Two surfaces provided on the sides facing each other in the axial direction of the recess extend in parallel to the radial direction, and a recess is provided between the two surfaces in the inner peripheral portion of the recess. A vibration type driving device characterized in that a curved surface is formed.   The vibration type driving device according to claim 1, wherein a plurality of the concave curved surfaces are formed. The plurality of concave curved surfaces are formed from the inner peripheral side of the concave portion toward the outer peripheral side,
4. The vibration type driving device according to claim 3, wherein a radius of curvature of the plurality of concave curved surfaces increases from an inner peripheral side to an outer peripheral side of the concave portion.   The vibration type driving device according to claim 1, wherein two concave curved surfaces are formed between the two surfaces, and a groove is formed between the two concave curved surfaces.   The vibration type driving device according to claim 1, wherein the two surfaces and the concave curved surface have roughness due to unevenness. A vibration type driving device according to any one of claims 1 to 6,
And a driven member driven by the vibration type driving device.