JP5871763B2 - Ultrasonic motor and lens apparatus having the same - Google Patents

Description

  The present invention relates to an ultrasonic motor that drives a driven part by generating an elliptical vibration in a pressed vibrator, and a lens device using the ultrasonic motor.

  Conventionally, for example, an ultrasonic motor has been adopted as a drive source for a camera or a lens, taking advantage of features such as silent operation, driving from low speed to high speed, and high torque output. The ultrasonic motor disclosed in Patent Document 1 includes an annular driven part having a rotation shaft and a plurality of vibrators including a contact part that comes into contact with the driven part. The vibrator is held in a state where it is pressed by the driven portion, and the contact portion of the vibrator is pressed against the driven portion and is in a so-called pressure contact state. When ultrasonic vibration is excited in the vibrator under the pressure contact state, an elliptical motion is generated in the contact portion of the vibrator, and the driven part is rotationally driven around the rotation axis of the driven part. The pressure contact state of the vibrator to the driven part can be obtained by urging the vibrator against the driven body with a leaf spring having a pressing convex part. By pressing and energizing the vicinity of the center of the vibrator with the pressing convex portion formed on the leaf spring, the contact portion of the vibrator is in pressure contact with the driven portion in a good state.

JP 2006-158052 A Japanese Patent Laid-Open No. 2004-304877

  However, the ultrasonic motor disclosed in Patent Document 1 has a problem that the vibrator is damaged when a large impact is applied due to dropping or malfunction.

  In a normal ultrasonic motor, in order to prevent the generation of sound in the audible range due to the resonance vibration of the rotor due to the ultrasonic vibration of the vibrator, the resonance frequency is set not to enter the audible range by increasing the mass of the rotor. doing. Then, when a large impact is applied in the direction from the rotor to the vibrator, there is a problem that the vibrator is damaged due to a striking force caused by a collision between the rotor, the vibrator, and the holding portion that holds the vibrator. .

  Similarly, for the holding part that holds the vibrator, the resonance frequency is increased by increasing the mass of the holding part in order to prevent the generation of audible sound due to the resonance vibration of the holding part accompanying the ultrasonic vibration of the vibrator. Is set not to enter the audible range. Then, when a large impact is applied in the direction from the vibrator to the rotor, there is a problem that the vibrator is damaged due to a striking force caused by a collision between the rotor, the vibrator, and the holding portion that holds the vibrator. .

The present invention has been made to solve the above problems, it also provides a and difficulty potatoes over data damage vibrator when the drop under or malfunction or the like is applied a large impact due With the goal.

The vibration type motor of the present invention is
A driven part having a contact surface;
A vibrator having a piezoelectric element, and at least one contact portion in contact with said contact surface, said contact portion transmits through the vibration of said excited by the piezoelectric element to the driven part, wherein A vibrator that drives the driven part; and
Pressurizing means for pressing the at least one contact portion against the driven portion;
A holding part for elastically holding the vibrator via the pressurizing means;
An ultrasonic motor comprising:
A part of the holding part forms an impact prevention part,
When the gap in the normal direction of the contact surface between the driven part and the impact prevention part is L1, and the minimum gap generated in the normal direction between the vibrator and the holding part is L2,
L1 <L2
And wherein and Turkey have been met.

According to the present invention, it is possible also to provide with difficulty potatoes over data damage vibrator when the drop under or malfunction or the like is applied large impact caused.

It is a disassembled perspective view of the ultrasonic motor in Example 1 of the present invention. It is a perspective view in the state where each member shown in Drawing 1 was built. It is an expansion perspective view which shows the joining state of a vibrator. (A) And (B) is an expanded sectional view showing the state where each member in Example 1 was incorporated. (C) is an enlarged detail view of part A of (B), showing a component vector of the pressing force of the elastic member. It is a figure which shows the clearance gap between the stopper of a ring base, and a rotor.

  Embodiments of the present invention will be described below with reference to the drawings. The ultrasonic motor of the present embodiment will be described by taking a rotary drive motor unitized as a drive actuator such as a lens barrel for a digital camera as an example, but the usage is not limited to this.

FIG. 1 is an exploded perspective view of an ultrasonic motor according to an embodiment of the present invention. In the drawings, the same members are indicated by the same symbols. Reference numeral 101 denotes a rotor which is a driven portion, which has an annular shape and includes a rotor contact surface 101a with which a vibrator 109 described later is in pressure contact. Reference numeral 102 denotes a diaphragm that comes into contact with the rotor contact surface 101a in a pressurized contact state with pressing, and reference numeral 103 denotes a piezoelectric element that is attached to the diaphragm 102 with an adhesive or the like. In a state where the piezoelectric element 103 is attached to the vibration plate 102, ultrasonic vibration can be generated by applying a voltage to the piezoelectric element 103, and an elliptical motion can be generated in the vibration plate 102. Reference numeral 104 denotes a small base on which the diaphragm 102 having the piezoelectric element 103 is attached and holds them. The vibrator 109 includes a diaphragm 102, a piezoelectric element 103, and a small base 104. In this embodiment, the rotor 101 is rotationally driven by the three vibrators 109 arranged so as to come into pressure contact with the rotor contact surface 101a parallel to the drive direction of the rotor 101. Reference numeral 105 denotes a ring base as a holding unit, which has an annular shape, and holds a vibrator 109, a pressurizing member 106, which will be described later, and a leaf spring 107. A pressure member 106 is fitted into the through hole 105b of the ring base 105 and is held so as to be movable only in a direction substantially perpendicular to the rotor contact surface 101a of the rotor 101. The vibrator 109 is brought into pressure contact with the rotor 101 via the small base 104 by the pressing force of. Reference numeral 107 denotes a leaf spring which is an elastic member. Both ends of the leaf spring are fixed to the ring base 105 with screws 108, and the vibrator and the driven portion are brought into pressure contact with the pressing force of the leaf spring. The pressing member 106 and the leaf spring 107 serve as the pressing unit of the present invention.
As described above, each member is incorporated and unitized as an ultrasonic motor.

  FIG. 2 is a perspective view showing a state in which each member of FIG. 1 is incorporated. In FIG. 2, the configuration around the vibrators 109 arranged in a circle on the rotor 101 is the same in all three places, and in order to prevent complexity of the drawing, reference numerals are attached only to the front side in the drawing. doing. As shown in the figure, a pressing force is applied to the vibrator 109 through the pressure member 106 by the leaf springs 107 fixed by two screws 108 at three locations on the ring base 105, respectively. The child 109 is biased and brought into pressure contact with the rotor contact surface 101a of the rotor 101. The ring base 105 includes a stopper 105 c that projects in the direction of the rotor 101 and serves as an impact prevention unit. The stoppers 105c are arranged between three vibrators 109 arranged along the circumference of the annular shape of the rotor 101, and there are three places like the vibrator 109, all having the same configuration. It has become. As will be described later, the stopper 105c of the ring base 105 has a stopper contact portion 105d facing the rotor contact surface 101a of the rotor 101, and a predetermined size is provided between the stopper surface 105d and the rotor contact surface 101a. A gap having a thickness is provided. This prevents the vibrator 109 and the ring base 105 from colliding and damaging the vibrator 109. When incorporated in an actual lens barrel or the like, the rotor 101 is driven by being connected to a focus mechanism or a zoom mechanism.

  Next, details of components of the ultrasonic motor will be described. FIG. 3 is an enlarged perspective view for explaining the joining state of the diaphragm 102 and the small base 104 in FIGS. 1 and 2 and is a view seen from the rotor 101 side. In the figure, two protrusions are formed on the flat plate portion 102a at the center of the diaphragm 102. Reference numeral 102 b denotes a protrusion contact surface as a contact portion formed on the upper end surface of the protrusion, and is a surface that contacts the rotor contact surface 101 a of the rotor 101. The two projecting contact surfaces are formed on the same plane, and are finished to a uniform surface by polishing or the like during the manufacturing process in order to improve the contact state with the rotor contact surface 101a.

  On the other hand, the piezoelectric element 103 is attached to the back surface side of the flat plate portion 102a shown in FIG. 3 (the surface side opposite to the surface having the two protruding portions) with an adhesive or the like. In addition, the attachment method of the back surface of the flat plate part 102a and the piezoelectric element 103 is not limited as long as it is attached. The piezoelectric element 103 is formed by laminating a plurality of piezoelectric element films. The laminated piezoelectric element 103 is excited by applying a desired AC voltage, and two vibration modes are excited in the diaphragm 102 to which the piezoelectric element 103 is attached. At this time, by setting the vibration phases of the two vibration modes to have a desired phase difference, an elliptical motion as indicated by an arrow in FIG. 3 occurs on the protrusion contact surface 102b. This elliptical motion is generated by three vibrators 109 as shown in FIGS. 1 and 2 and transmitted to the rotor contact surface 101a, whereby the rotor 101 can be driven to rotate. Note that details regarding the laminated structure and vibration mode of the piezoelectric element described above are the same as the contents described in Patent Document 2, and a description thereof will be omitted.

  Next, two joint portions 102 c are formed at both ends of the diaphragm 102 to join the upper surface portion 104 a formed on both sides of the small base 104. The diaphragm 102 is joined to the small base 104 by welding or adhesion at the joint 102c. However, as long as the diaphragm 102 and the small base 104 are joined, the method is not limited. Two arm portions 102d are formed between the two joint portions 102c and the flat plate portion 102a, and the flat plate portion 102a to which the piezoelectric element 103 is attached via the arm portions 102d is the small base 104. Fixed to. The arm portion 102d has a narrow shape with respect to the flat plate portion 102a and the bonding portion 102c as shown in FIG. 3 in order to make it difficult to transmit the vibration generated in the flat plate portion 102a to the bonding portion 102c. In other words, the arm portion 102d realizes a connection configuration in which the small base 104, which is a rigid body, does not inhibit the vibration generated in the flat plate portion 102a. In addition, a predetermined gap 203 is formed between the flat portion 104 b near the center of the small base 104 and a surface (not shown) facing the flat portion 104 b of the piezoelectric element 103.

  4 (A) and 4 (B) are enlarged sectional views showing a state in which each member is assembled, with the rotor 101 on the upper side. One of the three vibrators 109 in FIG. Only the area around the place is enlarged. The remaining two locations have the same configuration and will not be described.

  FIG. 4A shows the center of gravity of all the protrusion contact surfaces including two protrusion contact surfaces 102b that are in contact with the rotor contact surface 101a and parallel to the driving direction of the rotor 101, and the rotor contact surface 101a starting from the center of gravity. The plane containing the normal is the cut plane.

  4B includes the center of gravity of all the contact surfaces of the protrusions that contact the rotor contact surface 101a and the normal line of the rotor contact surface 101a in the diaphragm 102 in FIG. 3, and is orthogonal to the cut surface of FIG. 4A. The surface to be cut is the cut surface.

  However, the total protrusion contact surface includes all the protrusion contact surfaces 102b, and here includes two protrusion contact surfaces 102b. In addition, the center of gravity of the contact surface of all the protrusions (also referred to as the total contact center of gravity) includes an intersection of a center line 201 and a rotor contact surface 101a described later.

4A and 4B, 201 is a center line that passes through the center of gravity of all the protrusion contact surfaces that contact the rotor contact surface 101a of the diaphragm 102 and includes the normal line of the rotor contact surface 101a.
The protrusion contact surface 102b is in contact with the rotor contact surface 101a and is in a pressure contact state. Further, the diaphragm 102 is joined to the small base 104 at two upper surface portions 104a at the joint portions 102c at both ends. A predetermined gap 203 is formed between the piezoelectric element 103 and the flat portion 104 b of the small base 104.

  A hole 104c and an elongated hole 104d are provided on the lower surface side of the small base 104, and two shaft portions 105a formed on the ring base 105 are fitted. A contact portion 104 e is provided at the lower center of the small base 104. This contact portion 104e has an arc shape as shown in the figure in the cross section of FIG. 4A, and has a cylindrical shape extending in the depth direction of the paper (the left-right direction in FIG. 4B). It consists of parts. The contact portion 104e is in contact with the upper end surface 106a of the pressure member 106. Since the upper end surface 106a is formed as a flat surface, the contact with the contact portion 104e is a line contact having a length in the depth direction of the paper surface in FIG. 4A (the left-right direction in FIG. 4B). Become. In the present embodiment, the contact portion 104e is a part of the cylindrical shape having the arc shape as described above. However, if the contact portion 104e and the upper end surface 106a of the pressure member 106 can maintain a straight line contact, The shape is not limited.

  The ring base 105 has a through hole 105b on the surface facing the plate spring as shown in FIG. 1, and the pressure member 106 is fitted into the through hole 105b to come into contact with the plate spring. Thus, it can cooperate with the leaf spring. Note that the central axes of the through-hole portion 105b and the pressure member 106 substantially coincide with the center line 201, that is, the axial direction perpendicular to the rotor contact surface 101a. 4 (A) and 4 (B), the leaf spring 107 is deformed on the lower spherical surface portion 106b of the pressure member 106, and the pressure member 106 is elastically moved toward the small base 104 by an elastic force. Touching in an energized state.

  The leaf spring 107 needs to have a small spring constant to some extent in order to reduce variations in the pressing force due to changes in the deformation amount. Therefore, the leaf spring should be as thin as possible and the length should be as long as possible. The plate spring 107 of the present embodiment uses a thin plate, and is formed in an arc shape in order to make the length as long as possible in an annular ultrasonic motor. By doing so, even if a slight change occurs in the amount of displacement of the pressing member 106 in the pressing direction, the variation in the pressing force can be suppressed to be small. With the configuration described above, the vibrator 109 is pressed against the rotor 101 by the leaf spring 107 via the pressure member 106.

  Next, with reference to FIGS. 4A, 4 </ b> B, and 4 </ b> C, a structure for transmitting a pressing force by the leaf spring 107 will be described. In the following description, the pressing force vector is a force vector including the direction and magnitude of the pressing force in the cross section of each figure.

  First, in FIG. 4A, the small base 104 is in contact with the pressure member 106 at the contact portion 104e. In addition, the small base 104 is in contact with the rotor 101 at the protrusion contact surfaces 102b of the two protrusions, and the center of gravity of each protrusion contact surface 102b is at an approximately equal distance from the center line 201 in the driving direction of the rotor. . On the other hand, regarding the contact between the leaf spring 107 and the pressure member 106, in this embodiment, the leaf spring 107 is formed in an arc shape, so that the support portions at both ends of the leaf spring 107 and the input points of the pressing force (the leaf spring 107 and The contact point of the pressure member 106 does not exist on a straight line. Therefore, the cross section of the leaf spring 107 when the pressing force is generated may be in an inclined state as shown in FIG. In that case, as a result, the vector of the pressing force input to the pressing member 106 by the leaf spring 107 can be illustrated as an arrow 206a. The contact point between the pressing member 106 and the leaf spring 107 does not exist on the center line 201 and shifts to a point 205 on the right side of the center line in FIG.

  FIG. 4C shows an enlarged detailed view around the point 205 in the portion A of FIG. 4B. The pressing force applied to the pressing member 106 by the leaf spring 107 is represented by a vector 206 a and is inclined with respect to the center line 201. Therefore, the pressing force vector 206 a can be decomposed into a component vector 206 b in a direction parallel to the center line 201 and a component vector 206 c in a direction perpendicular to the center line 201.

  As shown in FIGS. 4A and 4B, the pressure member 106 is held by the ring base 105 with a degree of freedom only in a direction substantially parallel to the center line 201. That is, the pressure member 106 can move in a direction substantially parallel to the normal line of the rotor contact surface 101a, but movement in a direction substantially perpendicular to the normal line of the rotor contact surface 101a is restricted. . For this reason, the force (vector 204a) corresponding to the component (vector 206b) in the direction of the center line 201 among the pressing force (vector 206a) pressing the pressing member 106 by the leaf spring 107 is transmitted to the small base 104. .

  On the other hand, the pressing force (vector 204a) transmitted to the small base 104 is transmitted to the rotor contact surface 101a by the projection contact surfaces 102b of the two projections, and each projection contact surface 102b presses the rotor contact surface 101a. The force is a pressing force (vector 204b) that is half the pressing force vector 204a.

  In addition, since the contact between the protrusion contact surface 102b and the rotor contact surface 101a is a surface contact, in actuality, a pressing force uniformly distributed in the surface is presented. However, in order to facilitate understanding, the position of the center of gravity in the surface It is expressed as a vector of the force that works on. In addition, since the contact between the pressure member 106 and the contact portion 104e is a line contact, in reality, a pressing force uniformly distributed on the straight line in contact with the line is exhibited, but this also acts on the center of gravity position on the straight line. It is expressed as a vector. Hereinafter, surface contact and line contact are also expressed by a force vector at the center of gravity.

  Further, a frictional force generated by a component vector 206c in a direction perpendicular to the center line 201 of the pressing force vector 206a input to the pressing member 106 is generated by the leaf spring 107 on the side surface of the pressing member 106. On the other hand, a frictional force is also generated in the fitting at the shaft portion 105a. Since these frictional forces are sufficiently small with respect to the pressing force, they are ignored. In fact, if the finish on this side surface is smoothed to some extent, the influence of the frictional force can be reduced to a negligible level.

  In this embodiment, as described above, the pressure member 106 is generally held with respect to the ring base 105 in a state having a degree of freedom only in the direction of the center line 201. Therefore, the pressing force vector 204 a applied to the small base 104 by the pressing member 106 can be made to substantially coincide with the center line 201. At this time, the magnitude of the pressing force vector 204a is substantially equal to the component vector 206b in a direction parallel to the center line 201 of the pressing force vector 206a by the leaf spring 207. The component vector 206c in the direction perpendicular to the center line 201 of the pressing force vector 206a affects the frictional force at the side surface of the pressing member 106. Note that the side surface of the pressure member 106 and the inner surface of the through-hole portion 105b are finished smoothly, so that the generated frictional force is sufficiently smaller than the pressing force and hinders smooth advancement and retraction of the pressure member 106 in the direction of the center line 201. I don't have to. Finally, the pressing force vector applied to the rotor contact surface 101a by one protrusion 102b is 204b, and the magnitude thereof is half of the pressing force vector 204a. This is because, as shown in FIG. 4A, there are two protrusions 102b at substantially the same distance from the center line 201. Thus, as shown in FIGS. 4A and 4B, the force point of the input pressing force vector 206a is deviated from the center line 201, and the direction is not parallel to the center line 201. The two protrusion contact surfaces 102b can maintain a good pressure contact state with respect to the rotor contact surface 101a of the rotor 101.

  On the other hand, the small base 104 is pressed against the rotor contact surface 101a by the pressing member 106 via the contact portion on the straight line of the contact portion 104e. Therefore, in the cross section in FIG. 4A, the small base 104 can be tilted, and even if a dimensional error or assembly error during manufacturing, or a tilt of the member due to disturbance occurs, a satisfactory addition can be obtained. The pressure contact state can be maintained.

  FIG. 5 shows a state in which each member is incorporated and the rotor 101 is on the upper side, and the side surface of the ultrasonic motor is viewed from the normal direction of the cross section of FIG. Only one of the vibrators 109 is enlarged. The remaining two locations have the same configuration and will not be described.

  FIG. 5 is a diagram showing a state in which no impact is applied between the rotor 101 and the ring base 105 due to a drop or malfunction, and a gap L1 described later has a maximum value. The rotor 101 and the ring base 105 are relatively unmovable in the direction in which the gap L1 is expanded more than in the state of FIG. 5, but the direction in which the gap L1 is narrower than in the state of FIG. 5, that is, the maximum of the gap L1. In the range below the value, it can move relatively.

  In the present embodiment, as shown in the drawing, the ring base 105 is a surface facing the rotor contact surface 101a of the rotor 101, and is along a ring-shaped circumference parallel to the drive direction of the rotor 101. Between the three vibrators 109 arranged in this manner, there is a stopper 105c protruding in the direction of the rotor contact surface 101a. The stopper 105c may be formed integrally with the ring base 105, or may be attached to the ring base 105 by screw fixing, welding, or the like, but if the stopper 105c exists on the ring base, The method is not limited.

  The stopper 105c attached to the ring base 105 has a stopper contact portion 105d at a portion facing the rotor contact surface 101a, and the gap between the stopper contact portion 105d and the rotor contact surface 101a is shown in FIG. As shown, a gap L1 is provided. In addition, if the said clearance gap L1 is provided, the shape of the stopper 105c and the stopper contact part 105d, the number of attachments of the stopper 105c, and the attachment position to the stopper 105c ring base 105 will not be limited.

In a state where the vibrator 109 applies a predetermined amount of pressure to the rotor 101 by the leaf spring 107 and no impact due to a drop or malfunction is applied between the rotor 101 and the stopper 105c, the rotor contact surface 101a and the stopper 105c Let L1 be the gap in the normal direction of the rotor contact surface. On the other hand, when the minimum clearance in the normal direction of the rotor contact surface between the vibrator 109 and the ring base 105 in the above state is L2, the following conditional expression (1) is established for L1 and L2. doing.
L1 <L2 (1)

  By having the gap relationship as in the above conditional expression (1), even when an impact is applied in the direction of narrowing the gap L1 between the rotor contact surface 101a and the stopper 105c, the vibrator 109 is connected to the ring base 105. The rotor contact surface 101a and the stopper contact portion 105d of the stopper 105c provided on the ring base 105 come into contact with each other before they collide with each other. The leaf spring 107 is elastically deformed when the rotor contact surface 101a and the stopper contact portion 105d are in contact with each other.

  On the other hand, when an impact is applied upward in the drawing, the ring base 105 moves upward against the downward elastic force of the leaf spring 107, and the rotor 101 stops at the position shown in FIG. Further, when a large impact is applied downward in the drawing, the rotor 101 moves downward against the upward elastic force of the leaf spring 107, and the ring base 105 is stationary at the position shown in FIG. To do. That is, the relative position between the rotor 101 and the ring base 105 approaches even when a large impact is applied in any direction in the vertical direction of the drawing. However, as described above, there is the gap L1 between the rotor 101 and the stopper 105c of the ring base 105, and there is a conditional expression (1) between the minimum gap L2 between the vibrator 109 and the ring base 105. ) Is established. Therefore, even if the relative position of the rotor 101 and the ring base 105 approaches, the rotor contact surface 101a and the stopper contact portion 105b of the stopper 105c come into contact with each other, and further relative movement is restricted.

  As described above, even when the rotor 101 contacts the stopper 105c of the ring base 105, a gap L3 (= L2-L1) remains between the vibrator 109 and the ring base 105. The gap L3 prevents direct collision between the rotor 101, the vibrator 109, and the ring base 105, and as a result, damage to the vibrator 109 can be prevented.

  As described above, in the ultrasonic motor that drives the driven part by the ultrasonic vibration generated in the vibrator, the ring base 105 is provided with the stopper 105 c that protrudes toward the rotor contact surface 101 a of the rotor 101. In this way, even when a large impact is applied in the direction from the rotor 101 to the vibrator 109 or the direction from the vibrator 109 to the rotor 101 due to a drop or malfunction, the vibrator 109 and the ring It is possible to prevent the vibrator 109 from being damaged by directly colliding with the base 105.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary. For example, in the embodiments, description has been made with a rotor or ring base having an annular shape, but these shapes are not limited to an annular shape. For example, the same effect can be obtained even in a configuration in which the vibrators are linearly arranged and reciprocated linearly.

  By configuring the lens apparatus having the ultrasonic motor of this embodiment as a driving unit for driving a focus lens, a zoom lens, and the like, a lens apparatus that can enjoy the effects of the present invention can be realized.

101 Rotor (driven part)
101a Rotor contact surface (contact surface)
102 Diaphragm 102b Projection contact surface (contact part)
103 Piezoelectric element 104 Small base 104e Abutting part 105 Ring base (holding part)
105c Stopper (Shock prevention part)
105d Stopper contact portion 106 Pressure member 107 Leaf spring 109 Vibrator L1 Clearance between rotor and stopper

Claims (6)

A driven part having a contact surface;
A vibrator having a piezoelectric element and at least one contact portion in contact with the contact surface, transmitting vibrations excited by the piezoelectric element to the driven portion via the contact portion; A vibrator for driving the drive unit;
Pressurizing means for pressing the at least one contact portion against the driven portion;
A holding part for elastically holding the vibrator via the pressurizing means;
With
The holding portion has a shock prevention unit,
Resulting in the normal direction of the gap of the contact surface between the said contact surface with the impact prevention portion of the driven unit L1, in the normal direction between said contact portion and said holding portion of said vibrator When the minimum gap is L2,
L1 <L2
Vibration motor relation is satisfied, wherein the said contact surface with the impact prevention portion of the driven part, wherein contactable der Rukoto. In the range where the holding portion and the driven portion have the gap L1 equal to or less than a predetermined maximum value,
The vibration type motor according to claim 1, wherein the vibration type motor is relatively movable in the normal direction. 3. The vibration type motor according to claim 1 , wherein the impact prevention unit protrudes in the normal direction from the holding unit with respect to the driven unit . The driven part and the holding part each have an annular shape,
4. The vibration type motor according to claim 3, wherein the vibrator is disposed between the two impact prevention parts along the circumference of the annular shape of the holding part.   5. The vibration type motor according to claim 1, wherein the vibration type motor is an ultrasonic motor in which the vibration excited by the piezoelectric element is an ultrasonic vibration. 6.   A lens apparatus comprising the vibration type motor according to claim 1.

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