JP6808344B2 - Electronic devices equipped with vibration wave motors and vibration wave motors, lens barrels, imaging devices - Google Patents

Description

The present invention relates to a vibration wave motor.

Vibration wave motors (ultrasonic motors), which are widely used as drive sources for cameras and lenses by taking advantage of their features such as high torque output, high positioning accuracy, and quietness, are required to achieve both improved drive efficiency and miniaturization. ing. In Patent Document 1, in order to improve the driving efficiency, it is movable in the pressurizing direction between the vibrator holding member to which the ultrasonic vibrator is fixed and the pressurizing mechanism holding member, and in the moving direction. An ultrasonic motor having a connecting means for connecting without play is disclosed.

JP-A-2015-126692

However, although the ultrasonic motor of Patent Document 1 can improve the driving efficiency, it is difficult to reduce the size because the outer size of the ultrasonic motor when viewed in a plan view is enlarged by the rolling member and the leaf spring constituting the connecting means. ..

In view of such problems, it is an object of the present invention to provide a vibration wave motor capable of achieving both improvement in drive efficiency and miniaturization.

Vibration wave motor according to one aspect of the present invention, the transducer and a pressure means that pressurize the vibrator to the sliding member in contact with the vibrator, the vibration of the pressure applied by the pressurizing means A transmission member that transmits to a child, a first holding member that holds the oscillator, a second holding member that holds the transmission member, and a connecting means that connects the first and second holding members. A vibration wave motor in which the vibrator and the sliding member move relative to each other due to vibration generated in the vibrator, and a plurality of pressurizing means are separated from each other around the vibrator. The connecting means is arranged in parallel with a rolling member that moves the first and second holding members relative to the pressurizing direction of the pressurizing means and a rolling member that moves the vibrator and the sliding member relative to each other. A urging member for urging the first and second holding members is provided, the urging member is held by the second holding member, and the rolling member is the first and second holding members. It is characterized in that it is sandwiched by the oscillator and comes into contact with the first holding member on the central side of the oscillator in the relative movement direction of the oscillator and the sliding member.

According to the present invention, it is possible to provide a vibration wave motor capable of achieving both improvement in drive efficiency and miniaturization.

It is sectional drawing of the image pickup apparatus provided with the ultrasonic motor which concerns on embodiment of this invention. It is a block diagram of an ultrasonic motor. It is a partially enlarged view of an ultrasonic motor.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is a cross-sectional view of an imaging device which is an electronic device including an ultrasonic motor which is a vibration wave motor according to an embodiment of the present invention. The image pickup apparatus of this embodiment includes an image pickup lens unit 1 and a camera body 2. Inside the image pickup lens unit 1, an ultrasonic motor 3 and a focusing lens 4 attached to the ultrasonic motor 3 are arranged. An image sensor 5 is arranged inside the camera body 2. The focusing lens 4 is moved in parallel with the optical axis O by the ultrasonic motor 3 at the time of photographing. The subject image is imaged at the position of the image sensor 5, and the image sensor 5 generates a focused image. In the present embodiment, the ultrasonic motor 3 is mounted on the image pickup apparatus, but the present invention is not limited to this. The ultrasonic motor 3 may be mounted on an electronic device different from the image pickup device, for example, a lens barrel that can be attached to and detached from the image pickup device. Further, the ultrasonic motor 1 may be used not for moving the focusing lens 4 in parallel with the optical axis O but for moving the shake correction lens in a direction orthogonal to the optical axis O.

FIG. 2 is a block diagram of the ultrasonic motor 3. 2 (a) to 2 (d) are a perspective view, an exploded perspective view, a front view, and a side sectional view of the ultrasonic motor 3, respectively. FIG. 3 is a partially enlarged view of the ultrasonic motor 3. 3 (a) is a partially enlarged view of FIG. 2 (c), and FIG. 3 (b) is a partially enlarged view of FIG. 2 (d).

The friction member (sliding member) 101 and the guide support member (rail plate) 113 are fixed to the main plate (base) 112 by screws or the like. The pressurizing spring (pressurizing means) 110 is connected at four positions via spring hooks provided by the pressurizing transmission member (transmission member) 111 and the driving force transmission member (movable plate) 115, respectively, to connect the vibrator 104. A pressing force is applied to the friction member 101 for frictional contact. In the present embodiment, the pressure spring 110 applies the pressing force to the vibrator 104 at four positions, but the pressing force can be applied to the vibrator 104 at different positions by the plurality of pressing means. For example, the present invention is not limited to this. Further, the pressing force by the pressure spring 110 is orthogonal to the relative moving direction of the moving portion 120 described later.

The vibrator 104 includes a diaphragm 102 and a piezoelectric element 103. The diaphragm 102 and the piezoelectric element 103 are fixed by an adhesive or the like. The diaphragm 102 includes a contact portion which is a protruding portion provided on a surface opposite to the surface on the pressure transmitting member 111 side, and the contact portion is a friction member in a state of being pressurized by the pressure of the pressure spring 110. Contact 101. The piezoelectric element 103 excites ultrasonic vibration by applying a voltage. When the piezoelectric element 103 excites ultrasonic vibration in a state where the diaphragm 102 and the piezoelectric element 103 are adhered to each other, a resonance phenomenon occurs in the vibrator 104. At this time, two types of standing waves are generated in the vibrator 104, and a substantially elliptical motion is generated in the contact portion of the diaphragm 102.

The vibrator holding member (first holding member) 105 holds the vibrator 104 with an adhesive or the like. The pressurizing mechanism holding member (second holding member) 107, which is a holding housing for holding the pressurizing transmission member 111, comprises cylindrical rollers (rolling members) 108a and 108b and a leaf spring (biasing member) 109. It is connected to the vibrator holding member 105 via. The pressurizing mechanism holding member 107 includes a power extraction unit (not shown) connected to the driven body.

The elastic member 106 is arranged between the piezoelectric element 103 and the pressure transmitting member 111. In order to prevent damage to the piezoelectric element 103, the elastic member 106 prevents the pressure portion included in the pressure transmitting member 111 from coming into direct contact with the piezoelectric element 103.

The pressurizing mechanism holding member 107 and the movable plate 115 are fixed with screws or the like. The movable plate 115 is formed with three V-groove movement guide portions, and rolling balls 114a to 114c are fitted in the movement guide portions, respectively. The rail plate 113 is formed with three groove-shaped fixed side guide portions. The rolling ball 114 is sandwiched between a moving side guide portion formed on the movable plate 115 and a fixed side guide portion formed on the rail plate 113. In the present embodiment, the three fixed-side guide portions formed on the rail plate 113 are two V-grooves and one bottomed flat groove, but the rolling ball 114 is a groove capable of rolling. All you need is.

In the present embodiment, in order to reduce the thickness of the ultrasonic motor 3 in the Z-axis direction, the pressure springs 110 are not stacked on the top of the vibrator 104, but are arranged at intervals so as to surround the vibrator 104. There is. In the present embodiment, the pressure spring 110 can be made smaller by generating the pressing force by the plurality of pressure springs 110. The pressure spring 110 pressurizes the vibrator 104 against the friction member 101 in the direction of arrow C (pressurization direction) via the elastic member 106, so that the contact portion of the diaphragm 102 is pressed by the pressing force of the pressure spring 110. In this state, it comes into contact with the friction member 101. When a voltage is applied to the piezoelectric element 103 in this state, the substantially elliptical motion generated in the vibrator 104 is efficiently transmitted to the friction member 101. At this time, the moving portion 120 composed of the vibrator 104, the vibrator holding member 105, the elastic member 106, the pressurizing mechanism holding member 107, the pressurizing spring 110, the pressing force transmitting member 111, and the movable plate 115 is the optical axis O It can move relative to the friction member 101 in parallel with (X-axis).

Next, the connecting means 116 for connecting the vibrator holding member 105 and the pressurizing mechanism holding member 107 will be described. The connecting means 116 includes rollers 108a and 108b and a leaf spring 109. As shown in FIGS. 2 and 3, the rollers 108a and 108b are movably arranged between the vibrator holding member 105 and the pressurizing mechanism holding member 107 along the Z axis. The leaf spring 109 is arranged between the pressurizing mechanism holding member 107 and the roller (second rolling member) 108b, and has an urging force parallel to the X-axis. The leaf spring 109 urges the vibrator holding member 105 in the direction of arrow A and the pressurizing mechanism holding member 107 in the direction of arrow B via the roller 108b. As a result, the roller (first rolling member) 108a is sandwiched between the vibrator holding member 105 and the pressurizing mechanism holding member 107.

With the above configuration, the vibrator holding member 105 and the pressurizing mechanism holding member 107 can move along the Z axis by rolling the rollers 108a and 108b. Therefore, the vibrator holding member 105 and the pressurizing mechanism holding member 107 can be connected without inhibiting the ultrasonic vibration generated in the vibrator 104. Further, since the vibrator holding member 105 and the pressurizing mechanism holding member 107 can be connected in a direction parallel to the X axis, that is, in a moving direction of the moving portion 120, there is no delay in the response due to the backlash. As a result, the drive efficiency can be improved.

Further, the urging force of the leaf spring 109 is set to be larger than the inertial force due to acceleration / deceleration generated at the start and stop of driving of the vibrator 104. As a result, stable drive control can be realized because the oscillator 104 and the oscillator holding member 105 do not undergo relative displacement along the moving direction of the moving portion 120 due to the inertial force during driving.

In the present embodiment, the connecting means 116 is composed of rollers 108a, 108b and a leaf spring 109, but the present invention is not limited to this as long as it includes a rolling member and an urging member. For example, a ball or the like may be used instead of the roller. Further, in the present embodiment, the leaf spring 109 is used as the elastic member constituting the connecting means 116, but the urging member can eliminate the play between the vibrator holding member 105 and the pressurizing mechanism holding member 107. If so, the present invention is not limited to this.

Hereinafter, miniaturization of the external size of the ultrasonic motor 3 viewed in plan with respect to the XY plane will be described. In order to reduce the external size of the ultrasonic motor 3 viewed in plan with respect to the XY plane, the plurality of pressure springs 110 should be brought close to the center of the vibrator 104 located at the intersection of the X-axis and the Y-axis. Need to be placed. However, the connecting means 116 is provided with a structure for preventing the rollers 108a and 108b from falling off, and the leaf spring 109 needs to be increased to some extent in order to have the above-mentioned urging force. Therefore, the connecting means 116 becomes large. As a result, the external size of the ultrasonic motor 3 viewed in a plane with respect to the XY plane cannot be reduced.

Next, the positional relationship between the leaf spring 109 and the roller 108 will be described. In the following description, in the X-axis direction, the side closer to the center of the oscillator 104 is the center side, and the side away from the center of the oscillator 104 (opposite the center side) is the outside. When the vibrator holding member 105 holds the leaf spring 109 within its outer shape, the connecting means 116 is increased in size in order to avoid interference with other parts stacked and arranged at the center of the vibrator 104. Further, when the vibrator holding member 105 holds the leaf spring 109 outside its outer shape, the leaf spring 109 does not fit in the outer shape of the vibrator holding member 105, so that the pressurizing mechanism holding member 107 cannot be incorporated. ..

Therefore, in the present embodiment, the pressurizing mechanism holding member 107 holds the leaf spring 109 in order to reduce the outer size of the ultrasonic motor 3 when viewed in a plan view with respect to the XY plane. Further, the roller 108a abuts on the vibrator holding member 105 on the central side and abuts on the pressurizing mechanism holding member 107 on the outside. The roller 108b abuts on the oscillator holding member 105 on the central side and abuts on the leaf spring 109 held by the pressurizing mechanism holding member 107 on the outside. By holding the leaf spring 109 by the pressurizing mechanism holding member 107, the piezoelectric element 103, the elastic member 106, the pressing force transmitting member 111, etc. are stacked and arranged in the central portion of the vibrator 104 without impairing the assembling property. It is possible to avoid interference with other parts. Therefore, the plurality of springs 110 can be arranged close to the central portion of the vibrator 104, and the outer size of the moving portion 120 viewed in plan with respect to the XY plane can be reduced.

Further, the connecting means 116 needs to be provided with a dropout prevention structure for preventing the rollers 108a and 108b from falling off. In the present embodiment, the vibrator holding member 105 and the pressurizing mechanism holding member 107 are provided with a structure for preventing the rollers 108a and 108b from falling off in the direction of arrow C. Further, since the length of the roller 108a in the Y-axis direction can be shortened, it is possible to provide the pressurizing mechanism holding member 107 with a structure for preventing the rollers 108a and 108b from falling off in the Y-axis direction. On the other hand, the roller 108b in contact with the leaf spring 109 needs to have a size such that the leaf spring 109 has the above-mentioned urging force, so that the length in the Y-axis direction cannot be shortened. Therefore, when the pressurizing mechanism holding member 107 is provided with a structure for preventing the roller 108b from falling off in the Y-axis direction, the outer size of the ultrasonic motor 3 viewed in plan with respect to the XY plane becomes large. Therefore, in the present embodiment, the leaf spring 109 is provided with the fall prevention portion 130 as a fall prevention structure of the roller 108b in the Y-axis direction. With such a configuration, it is possible to further reduce the outer size of the ultrasonic motor 3 in a plan view with respect to the XY plane. In the present embodiment, as shown in FIG. 3A, the fall-off prevention portion 130 is provided by bending both ends of the leaf spring 109, but the roller 108b can be prevented from falling off in the Y-axis direction. The present invention is not limited to this as long as the configuration is simple.

As described above, in the present embodiment, it is possible to provide an ultrasonic motor capable of achieving both improvement in drive efficiency and miniaturization.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof. For example, in the present embodiment, the configuration in which the vibrator 104 of the ultrasonic motor 3 moves and the friction member 101 does not move has been described, but the vibrator 104 may not move and the friction member 101 may move. Further, the ultrasonic motor 3 of the present embodiment includes a friction member 101 as a fixed portion that does not move, but the vibrator 104 is in frictional contact with a member other than the ultrasonic motor 3 (for example, a part of a lens holding frame). The ultrasonic motor 3 may not be provided with the friction member 101.

3 Ultrasonic motor (vibration wave motor)
101 Friction member (sliding member)
104 Oscillator 105 Oscillator holding member (first holding member)
107 Pressurizing mechanism holding member (second holding member)
108 Roller (rolling member)
109 Leaf spring (urging member)
110 Pressurizing spring (pressurizing means)
111 Pressurized pressure transmission member (transmission member)
116 Connecting means

Claims (14)

Oscillator and
A pressurizing means for pressurizing the oscillator against a sliding member in contact with the oscillator,
A transmission member that transmits the pressing force by the pressurizing means to the vibrator,
A first holding member for holding the vibrator and
A second holding member that holds the transmission member and
It has a connecting means for connecting the first and second holding members.
A vibration wave motor in which the vibrator and the sliding member move relative to each other due to the vibration generated in the vibrator.
A plurality of the pressurizing means are arranged around the vibrator so as to be separated from each other.
The connecting means includes a rolling member that moves the first and second holding members relative to the pressurizing direction of the pressurizing means, and the first connecting means parallel to the relative moving direction of the vibrator and the sliding member. And with an urging member to urge the second holding member
The urging member is held by the second holding member and
The rolling member is sandwiched by the first and second holding members, and comes into contact with the first holding member on the central side of the vibrator in the relative movement direction between the vibrator and the sliding member. A characteristic vibration wave motor. The vibration according to claim 1, wherein the urging member includes a fall-out prevention portion having a shape that restricts the movement of the rolling member in a direction orthogonal to the pressurizing direction and the relative moving direction. Wave motor. The vibration wave motor according to claim 1 or 2, wherein a plurality of the pressurizing means are arranged apart from each other so as to surround the vibrator. The vibration wave motor according to any one of claims 1 to 3, wherein the pressurizing direction is orthogonal to the relative moving direction of the vibrator and the sliding member. The claim is characterized in that the urging force of the urging member is set to be larger than the inertial force applied to the first holding member when the vibrator and the sliding member move relative to each other. Item 4. The vibration wave motor according to any one of Items 1 to 4. The rolling member abuts on the first holding member on the center side of the vibrator in the relative movement direction of the vibrator and the sliding member, and the first is on the side opposite to the center side of the vibrator. A first rolling member that comes into contact with the holding member 2 and a second rolling member that comes into contact with the first holding member on the center side of the vibrator and abuts with the urging member on the opposite side. The vibration wave motor according to any one of claims 1 to 5, wherein the vibration wave motor is provided. The vibration wave motor according to claim 6, wherein the length of the first rolling member is shorter than the length of the second rolling member. The vibration wave motor according to any one of claims 1 to 7, wherein the urging member is a leaf spring. The vibration wave motor according to any one of claims 1 to 8, wherein the rolling member is a cylindrical roller. The vibrator according to any one of claims 1 to 9, wherein the vibrator includes a diaphragm that comes into contact with the sliding member and a piezoelectric element that excites ultrasonic vibration by applying a voltage. Vibration wave motor. An electronic device comprising the vibration wave motor according to any one of claims 1 to 10. The vibration wave motor according to any one of claims 1 to 10.
With a lens,
A lens barrel characterized by using the vibration wave motor to move the lens in a direction parallel to the optical axis of the lens or a direction orthogonal to the optical axis of the lens. The lens barrel according to claim 12, wherein the lens barrel is removable from the imaging device. An imaging device including the lens barrel according to claim 12.