JP6708471B2 - Vibration wave motor and optical device equipped with the vibration wave motor - Google Patents

Description

The present invention relates to a vibration wave motor.

Conventionally, in an ultrasonic motor, a sliding member is driven by applying a high-frequency voltage to a vibrator that periodically oscillates to bring the vibrator into contact with the sliding member. In Patent Document 1, the vibrator is freely movable in a pressing direction with respect to a frame member to be held, is in contact with a sliding member without a gap, and is biased in a relative moving direction. It has a structure that can be connected without play.

JP, 2005-126692, A

However, in Patent Document 1, since the metal leaf spring is used as the biasing member that constitutes the connecting means, if the metal leaf spring is also downsized as the unit is downsized, the biasing member It becomes difficult to secure an elastic displacement region for generating a desired biasing force. Therefore, the urging force is insufficient, or the urging member is plastically deformed with a small displacement amount, so that the play absorption region is extremely small. For this reason, it has been difficult to further reduce the size of the connecting means in the conventional urging means using a metal leaf spring.

An object of the present invention is to provide a vibration wave motor in which the entire unit is downsized.

In order to achieve the above object, a vibration wave motor according to the present invention includes a vibrator that vibrates by an applied high-frequency voltage, a vibrator base to which the vibrator is fixed, and a frame that holds the vibrator base. A vibration wave having a member and a connecting means for connecting the vibrator base and the frame member to each other, and the vibrator and the sliding member that is in frictional contact with the vibrator due to the vibration relatively move. In the motor, the vibrator base is connected to the frame member by the connecting means at one position on one side in the relative movement direction, and is not in contact with the frame member on the opposite side to the one side. The connecting means includes one rolling member and a magnetic force member, and the vibrator base and the frame member are biased by the magnetic force generated by the magnetic force member via the rolling member. It is characterized by

According to the present invention, it is possible to provide a vibration wave motor in which the entire unit is downsized.

It is a sectional view of the vibration wave motor 3 of the present invention in the Y-axis direction. (A) It is sectional drawing of the vibration wave motor 3 of this invention in the X-axis direction. (B) It is an enlarged view. (A) It is an exploded perspective view which shows the connection means of the conventional structure. (B) It is an exploded perspective view showing the connecting means 121 of the present invention. (A) ~ (C) is a diagram showing the relative operation of the vibrator 100 and the vibrator base 102 of the present invention. (A), (B) It is a figure which shows Example 1 and Example 2 of the vibration wave motor 3 of this invention. It is sectional drawing which shows the application example which applied the vibration wave motor 3 of this invention to the lens barrel 2 of an optical device.

Hereinafter, the vibration wave motor 3 (ultrasonic motor) of the embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, the outline of the present invention will be described. In the present invention, even if the space in one direction cannot be secured due to space saving, the magnetic force is used in the structure of the connecting means 121 to secure the volume space (space) which is the product of the width and the thickness. If so, a biasing force can be obtained. Further, by keeping the distance between the member that generates the magnetic force and the magnetic member constant, a stable biasing force can be obtained, and there is no fear of elastic deformation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same parts are designated by the same reference numerals. In addition, the moving direction of the vibrator 100 of the vibration wave motor 3 is the X-axis direction, the pressing direction in which the vibrator 100 is pressed is the Z-axis direction, and the direction orthogonal to both the X-axis direction and the Z-axis direction is the Y-axis direction. It is defined as. FIG. 1 is a cross-sectional view (cross-sectional view in a direction perpendicular to the moving direction) of a vibration wave motor 3 showing an embodiment of the present invention, and FIG. 2A is a vibration showing the embodiment of the present invention. It is a principal part sectional drawing in the moving direction of the wave motor 3. FIG. 2B is an enlarged view of a portion that constitutes the connecting means 121 described later. Further, although the present embodiment will be described by taking the direct acting (linear) vibration wave motor 3 as an example, the vibration wave motor 3 can be applied to a rotary type and other types.

The vibration wave motor 3 includes a diaphragm 101. The diaphragm 101 is fixed to the vibrator base 102 holding the vibrator 100 by adhesion or the like. The vibrator base 102 has a frame shape and is made of resin or metal thicker than the diaphragm 101.

A piezoelectric element 103 is fixed to the vibration plate 101 with an adhesive or the like. The piezoelectric element 103 is set so that when a high frequency voltage is applied, the diaphragm 101 resonates in each of the longitudinal direction and the lateral direction. The vibrating plate 101 and the piezoelectric element 103 form the vibrator 100. The vibrator 100 is configured to vibrate at a frequency in the ultrasonic range when a high frequency voltage is applied.

As a result, as shown in FIG. 2A, the tip of the press contact portion 101a formed on the vibration plate 101 causes an elliptical motion. By changing the frequency and the phase of the high-frequency voltage applied to the piezoelectric element 103, it is possible to appropriately change the rotation direction and the ellipticity to generate a desired movement. As a result, a driving force for relatively moving is generated by frictionally contacting the slider 115 as a sliding member which is a counterpart component, and the vibrator 100 is moved in a relative movement direction indicated by an arrow X (a direction perpendicular to the paper surface of FIG. 2(A) can be driven in the left-right direction. Note that this relative movement direction corresponds to the optical axis OL direction in the lens barrel in which the vibration wave motor 3 described later is incorporated. The slider 115 is fixed to a unit support member 117, which will be described later, by fastening means (screws). In the present embodiment, the vibrator 100 moves and the slider 115 does not move, but the vibrator 100 may not move but the slider 115 may move. Further, the slider 115 may not be included in the constituent requirements of the vibration wave motor 3, and a part of the members other than the vibration wave motor 3 may be used as the sliding member.

In FIGS. 2A and 2B, the frame member 105 is connected to the vibrator base 102 to which the vibrator 100 is fixed by the connecting means 121. In FIG. 2A, a cylindrical roller 106 that is a rolling member is provided at one location on one side outside the location of the pressure contact portion 101a of the diaphragm 101. That is, the roller 106 is provided at one position in the moving direction of the vibrator 100.

The view enclosed by the broken line circle in FIG. 2B is an enlarged cross-sectional view of the connecting means 121. An extension portion 105a extending downward is formed on the frame member 105, and is a magnet 107a and a magnetic member that form a magnetic force member 107 between the connecting portion 102b of the vibrator base 102 and the extension portion 105a. Two magnetic metal plates 107b1 and 107b2 and a roller 106 are incorporated. The magnet 107a having a predetermined magnetic force is fixed to the connecting portion 102b of the vibrator base 102 together with the right side magnetic sheet metal 107b1. The other left side magnetic sheet metal 107b2 is fixed to the extending portion 105a of the frame member 105. At this time, due to the magnetic force generated between the magnet 107a and the left side magnetic metal plate 107b2, the vibrator base 102 and the frame member 105 are connected in the left-right direction of FIG. It is movable in the pressing direction Z. In this way, the roller 106 and the magnetic force member 107 constitute the connecting means 121 of the present invention.

The magnetic force at this time is applied in a direction (direction equal to the relative movement direction) orthogonal to the pressing direction Z of the vibrator 100 described later. With the above configuration, there is no play in the relative movement direction, and in the pressing direction Z (vertical direction in FIG. 2A), the sliding resistance is hardly generated by the action of the roller 106. Means 121 can be implemented. At this time, the urging force of the magnet 107a is larger than the inertial force due to acceleration/deceleration that occurs when the frame member 105 and the driven parts (the focus lens holding frame 15 and the focus lens G2 in FIG. 6) to be described later start and stop. Is set. With this setting, the vibrator base 102, the vibrator 100, and the frame member 105 can realize stable drive control without relative displacement in the moving direction due to inertial force during driving.

The pressure plate 108 is configured to press and hold the piezoelectric element 103 with an elastic member 109 having flexibility, which will be described later, interposed therebetween. The pressure spring 110 is incorporated between the spring holding member 111 and the spring base plate 112, and is configured as a pressure spring unit. At this time, since the large-diameter portion 111a provided at the tip of the spring holding member 111 is loosely fitted in the fitting portion 112a of the spring base plate 112, the large-diameter portion 111a resists the spring force of the pressure spring 110 after the fitting. Can maintain the unit state.

On the outer diameter portion of the spring base plate 112, bayonet protrusions 112b are formed at several positions in the circumferential direction. In the assembled state, the bayonet protrusion 112b defines the position in the pressing direction Z by the bayonet engaging portion 105c formed on the frame member 105. At this time, the pressing portion 111 b provided at the tip of the spring holding member 111 presses the vibrator 100 against the slider 115 via the pressing plate 108 and the elastic member 109 by the urging force of the pressing spring 110. Therefore, the vibrator 100 and the slider 115 can be brought into frictional contact with each other. The pressure spring 110, the spring holding member 111, and the spring base plate 112 constitute the pressure means 120.

The moving plate 113 forming a part of the guide portion is fixed to the contact portion 105b of the frame member 105 by adhesion or screwing. Grooves 113a having a plurality of V-shaped cross sections for guiding the frame member 105 in the optical axis direction are formed on the moving plate 113, and the balls 114 are arranged in the grooves 113a. The cover plate 116 is fixed to the unit supporting member 117 with screws.

The cover plate 116 also constitutes a part of the aforementioned guide portion, and the cover plate 116 is provided with a groove portion 116a having a V-shaped cross section at a position facing the groove portion 113a of the moving plate 113, and the groove portion 113a. The ball 114 is held by the groove portion 116a. With such a configuration, it is possible to support the frame member 105 so as to be able to move back and forth along the moving direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2A). The linear motion type vibration wave motor 3 according to the embodiment of the present invention is completed with the above configuration.

FIG. 3A is an exploded perspective view showing the structure of the connecting means of the vibrator 200 according to the prior art, and FIG. 3B is an exploded perspective view showing the structure of the connecting means 121 of the vibrator 100 of the present invention. Is. In the case of the configuration of the conventional technique, the leaf spring 207 is used to bias the vibrator base 202 toward the frame member 205 in the relative movement direction, and two rollers 206a and 206b are required. The leaf spring 207 is fixed to the vibrator base 202 by an adhesive means (not shown) or the like, and urges the frame member 205 in the negative direction of the X axis of FIG. 3A via the roller 206a with the connecting portion 202a as an end. To do. Then, the frame member 205 is urged toward the connecting portion 202b of the vibrator base 202 via the roller 206b on the right side of the paper surface of FIG. At this time, the movement restriction of the vibrator base 202 by the bias is the same as that of the configuration of the present invention.

Here, the vibration wave motor 3 is limited in space in the Y-axis direction in FIG. 3A because it is incorporated in a lens barrel portion of an optical device to be described later. In the configuration of the related art, when the dimension in the Y-axis direction is shortened, the length L of the beam of the leaf spring 207 is shortened, so that it is difficult to secure the elastic displacement region for obtaining the biasing force. That is, it is very difficult to reduce the dimension in the Y-axis direction with the configuration of the conventional technique.

On the other hand, in the structure of the connecting means 121 of the present invention shown in FIG. 3B, the magnetic force generated by the magnet 107a has a thickness in the X-axis direction, a width in the Z-axis direction, and a Y-axis direction. It is determined by the volume, which is the product of the dimensions. That is, even when the dimension in the Y-axis direction in FIG. 3(A) is short, if the above-mentioned volume can be obtained, it is possible to obtain a biasing force that satisfies the requirements of the present invention. Further, in FIG. 3B, the magnet 107a and the roller 106 are always in contact with each other, and since the distance is constant, a stable biasing force can be obtained. With such a configuration, the connecting means 121 for connecting the vibrator 100 relative to the frame member 105 in the pressurizing direction Z and connecting the vibrator 100 without play in the relative moving direction can be downsized, and the unit can be downsized. It is possible to provide the vibration wave motor 3 whose size is reduced.

Next, the relative operation of the vibrator base 102 including the vibrator 100 and the frame member 105, which is realized by the connecting means 121 of the present invention, will be described with reference to FIGS. The drawing enclosed by the broken line circle in each drawing shows an enlarged sectional view of the connecting means 121. In FIG. 4(A), the roller 106 contacts the magnetic sheet metal 107b2 on the frame member 105 side at the contact point 106a at the left end of the roller 106, and similarly contacts the substantially central portion of the magnet 107a in the Z-axis direction at the contact point 106b at the right end. It shows the state. Then, the positional relationship between the vibrator base 102 and the frame member 105 in a so-called normal state in which the two pressure contact portions 101a of the diaphragm 101 are located on the reference line 300 shown by a broken line parallel to the X-axis direction is shown. Has been done.

FIG. 4B shows a state in which the vibrator base 102 is lowered downward in the Z-axis direction relative to the frame member 105. That is, the state in which it is lower than the normal state, that is, the two pressure contact portions 101 a of the diaphragm 101 is lower than the reference line 300. At this time, the roller 106 rotates clockwise, and the left and right contact points 106 a and 106 b with the vibrator base 102 and the frame member 105 move in opposite directions on the circumference of the roller 106. In this way, the relative movement in the vertical direction with a small sliding resistance is possible while maintaining the backlash in the horizontal direction on the paper surface. Further, even when the vibration plate 101 and the vibrator base 102 are relatively raised with respect to the frame member 105, the same operation is possible by the roller 106 rotating in the reverse direction.

FIG. 4C shows a state in which the vibrator base 102 is rotated clockwise relative to the frame member 105. At this time, the roller 106 does not rotate, and the contact point 106b with the vibrator base 102 side shifts downward in the Z-axis direction. In this way, relative movement in the turning direction with less sliding resistance is possible while keeping the back-and-left direction in the plane of the drawing free from play. Further, even when the oscillator base 102 rotates counterclockwise relative to the frame member 105, the same operation can be performed by shifting the contact point to the opposite direction, that is, the upward direction.

Rotation of the vibrator 100 and the vibrator base 102 connected thereto about a straight line connecting two contact points where the two pressure contact portions 101a of the vibrator 100 contact the slider 115 is called rolling. In order to prevent this rolling, a sliding guide (not shown) may be provided in which the vibrator base 102 and the frame member 105 contact or slide in a direction orthogonal to the relative movement direction. The sliding guide is in the shape of a wall, and has a role of guiding the vibrator base 102 and the frame member 105 so as not to shift.

As described above, the frame member 105 and the vibrator base 102 to which the vibrator 100 is fixed are connected via the roller 106, the magnet 107a, and the magnetic metal plates 107b1 and 107b2. As a result, it is possible to arrange the connecting means 121 in a narrow space, which does not rattle in the relative movement direction and has a small sliding resistance.

(Example 1)
Example 1 of the present invention will be described with reference to FIG. In the first embodiment, the magnet 107a is polarized so as to have the center 301 of the pole, and the roller 106 formed of magnetic metal has the pole of the magnet 107a in the stable position in the direction perpendicular to the biasing force of the magnetic force. It is located at the center 301. In a certain neighboring area (stable area) centered on this stable position, the roller 106 can roll stably and freely without being largely restricted in the vertical direction of the paper surface. At this time, since the amount of displacement of the elliptic motion of the diaphragm 101 in the pressing direction Z is sufficiently small with respect to this stable region, the magnetic force does not become rolling resistance.

Further, since the biasing force due to the magnetic force passes through the center of the roller 106, a moment that rotates the vibrator base 102 is unlikely to occur. That is, the urging force of the magnetic force acts as a force to make the roller 106 stand at the neutral position, and the roller 106 can be positioned at the center 301 of the pole. Then, the force to make it stand functions as a function of preventing the frame member 105 and the vibrator base 102 from coming off. Further, the magnetic force lines 303 by the magnetic force member 107 are formed as a closed magnetic path by sandwiching both sides of the magnet 107a with the magnetic metal plates 107b1 and 107b2. Therefore, the influence of the magnetic force on the outside of the magnetic force member 107 can be suppressed.

(Example 2)
Next, FIG. 5B shows a second embodiment of the present invention. The roller 106 is located at the center 302 of the pole of the magnet 107a, which is another stable position other than the above in the direction perpendicular to the biasing force. In a constant neighborhood area (stable area) centered on this stable position, the roller 106 can roll freely and stably without being subject to large restrictions in the vertical direction of the paper surface, as described above. In this way, the roller 106 can be positioned according to the polarization state of the magnet 107a. Further, in the second embodiment as well, the magnet 107a is sandwiched by the magnetic metal plates 107b1 and 107b2 to form a closed magnetic path, so that the influence of the magnetic force on the outside of the magnetic force member 107 can be suppressed.

(Application example)
FIG. 6 is a sectional view showing an application example in which the vibration wave motor 3 of the present invention is mounted on the lens barrel 2 which is an optical device. In this application example, the case where the lens barrel 2 is an interchangeable lens that can be exchanged with the camera body 1 will be described. Since the lens barrel 2 is substantially axisymmetric, only the upper half of the lens barrel 2 is shown. Further, in FIG. 6, the lens barrel 2 is attachable/detachable to/from the camera body 1, but the imaging device, which is an optical device, may have the vibration wave motor 3 built therein.

A lens barrel 2 is detachably attached to the camera body 1, and an image pickup device 1a is provided in the camera body 1. The mount 11 has a flange portion and a bayonet portion for attaching the lens barrel 2 to the camera body 1. The fixed barrel 12 contacts the flange portion of the mount 11 and fixes the mount 11 with screws (not shown). The front barrel 13 holding the first lens G1 and the rear barrel 14 holding the third lens G3 are fixed to the fixed barrel 12.

The focus lens G2 is held by the focus lens holding frame 15. The focus lens holding frame 15 is connected to an output section (not shown) of the vibration wave motor 3 and is movable linearly by a known guide bar 16 held by the front lens barrel 13 and the rear lens barrel 14. There is. A flange portion (not shown) is formed on the unit supporting member 117 of the vibration wave motor 3 and is fixed to the rear lens barrel 14 with a screw.

When the vibrator 100 that is the drive unit of the vibration wave motor 3 is driven with the above-described configuration, the driving force of the vibration wave motor 3 is transmitted to the focus lens holding frame 15 via the driving force transmission unit 104. It The focus lens holding frame 15 linearly moves on the guide bar 16 by the driving force of the vibrator 100. The vibration wave motor 3 may be used not only for moving the focus lens, but also for moving the zoom lens and the image shake correction lens.

The application examples of the vibration wave motor 3 and the optical device incorporating the vibration wave motor 3 according to the embodiments and examples of the present invention have been described in detail above, but the present invention is not limited to the above embodiments and examples. Various forms can be taken without departing from the scope of the claims.

2 lens barrel (optical equipment)
3 vibration wave motor 100 vibrator 102 vibrator base 105 frame member 106 roller (rolling member)
107 magnetic force member 107a magnets 107b1 and 107b2 magnetic sheet metal (magnetic member)
115 Slider (sliding member)
120 pressurizing means 121 connecting means 303 magnetic field lines

Claims (12)

A vibrator that vibrates due to the applied high-frequency voltage,
A vibrator base on which the vibrator is fixed,
A frame member for holding the vibrator base,
A connecting means for connecting the vibrator base and the frame member,
A vibration wave motor in which the vibrator and a sliding member in frictional contact with the vibrator move relative to each other by the vibration,
The vibrator base is connected to the frame member by the connecting means at one location on one side in the relative movement direction, and is in non-contact with the frame member on the opposite side to the one side,
The connecting means is composed of one rolling member and a magnetic force member, and the vibrator base and the frame member are biased by the magnetic force generated by the magnetic force member via the rolling member. Vibration wave motor characterized by. The vibration wave motor according to claim 1, wherein the rolling member and the magnetic force member are arranged along a direction of the relative movement. The magnetic force member is composed of a magnet and two magnetic members, one magnetic member is provided on the vibrator base and the other magnetic member is provided on the frame member, and the connecting means is the rolling member. 3. The vibration wave motor according to claim 1, wherein the vibration wave motor is sandwiched between the magnet and the one magnetic member, and the vibrator base and the frame member are connected to each other. 4. The rolling member is made of magnetic metal, and the magnetic force member positions the rolling member in a direction perpendicular to the direction of the relative movement depending on a polarization state of the magnetic member. The vibration wave motor according to the item. The vibration wave motor according to any one of claims 1 to 4, wherein a sliding guide is provided between the vibrator base and the frame member. In the rolling member, a force that tends to settle at a neutral position of the magnetic force generated by the magnetic force member is generated, and the force serves as a retaining action between the vibrator base and the frame member. The vibration wave motor according to any one of claims 1 to 5. The vibration wave motor according to any one of claims 1 to 6, wherein the rolling member is made of magnetic metal, and the biasing force of the magnetic force generated by the magnetic force member is strengthened. The vibration wave motor according to any one of claims 1 to 7, wherein the magnetic force line generated by the magnetic force member is closed between the members forming the coupling means. Said transducer pressurizing means for pressurizing and further perforated to said sliding member, said magnetic member and said Rukoto is polarized in the pressing direction of the pressing means, any of claims 1 to 8 The vibration wave motor according to item 1. The vibration wave motor according to any one of claims 1 to 9, wherein the vibration wave motor is an ultrasonic motor that vibrates at a frequency in an ultrasonic range. The magnetic force acts as a retainer for the frame member and the oscillator base when the relative position of the oscillator base and the frame member changes in a direction perpendicular to the relative movement direction. The vibration wave motor according to any one of claims 1 to 10, characterized in that. An optical device equipped with the vibration wave motor according to claim 1.

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