JP5669446B2 - Driving mechanism of moving body - Google Patents

Description

The present invention uses a called vibration type driving apparatus and an ultrasonic motor, a driving mechanism of a moving body to drive the moving body.

In the field of the vibration type drive device, a vibration type drive device that generates a linear motion called a so-called linear ultrasonic motor has been developed and put into practical use.
The linear ultrasonic motor has characteristics such that a large output can be obtained as compared with the size and the controllability is excellent.
For this reason, many actuators for driving an optical system such as an optical axis direction drive of a lens group have been proposed, particularly in an actuator that rotationally drives a lens barrel such as a camera.

For driving such a lens group, for example, Patent Document 1 proposes the following vibration actuator.
In this vibration actuator, the moving lens group is fixed to a lens holder, and the lens holder is guided by a first guide bar and a second guide bar so as to be moved in a predetermined direction.
In addition, one vibrator is fixed to the lens holder, and this vibrator and the first guide bar are configured to be pressed and contacted using the elastic force of an elastic body that constitutes the vibration portion of the vibrator. ing.
By the ultrasonic vibration of the vibrator, a relative moving force is generated between the vibrator and the first guide bar, and the lens holder and the moving lens group are linearly moved along the guide bar.
According to this configuration, since the drive output is directly transmitted to the guide bar, the configuration can be reduced in size.
Here, the first guide bar has a function of giving the lens holder freedom of movement in the desired linear movement direction and restricting movement in two directions orthogonal to the movement direction of the lens holder.
The second guide bar has a function of restricting rotation around the central axis of the first guide bar of the lens holder.
By restricting the movement of these lens holders, the lens holders are configured to be given a degree of freedom of only linear movement in a desired direction.

JP-A-8-182354

However, in Patent Document 1 in the above-described conventional example, the elastic force of the elastic body constituting the vibrating portion of the vibrator is used for the pressure contact between the vibrator and the first guide bar. It has the following problems.
That is, in this conventional vibration actuator, the output for moving the first guide bar in pressure contact with the vibrator relative to the ultrasonic vibration of the vibrator is obtained by the friction force of the pressure contact due to the elastic force of the elastic body. It has been.
However, on the other hand, this frictional force acts as a force that inhibits the sliding of the lens holder when the lens holder slides on the guide bar, and prevents smooth sliding of the lens holder.
Therefore, if a frictional force reducing material such as grease is applied to the surface of the guide bar, the output due to the frictional force that moves the first guide bar in pressure contact with the vibrator relative to the ultrasonic vibration of the vibrator is hindered. It will be.
As described above, in the conventional example in which the elastic force of the elastic body of the vibrator is used for the press contact, the frictional force for moving the vibrator and the first guide bar relative to each other is secured, and the lens holder In terms of achieving both smooth sliding with respect to the guide bar, satisfaction is not necessarily obtained.

In view of the above problems, the present invention does not impede the frictional force generated when the relative moving force is generated between the vibrator and the guide bar in frictional contact, and smoothly slides the moving body along the guide bar. it is an object of the invention to provide a driving mechanism capable and Do that moving body.

According to one aspect of the present invention, there is provided a moving body to which a vibrator having at least an electromechanical energy conversion element and an elastic body on which a contact portion is formed is fixed;
A first guide bar and a second guide bar arranged in parallel to hold the movable body slidably,
By applying a driving voltage to the electro-mechanical energy conversion element, a relative moving force is generated between the second guide bar and the contact portion of the vibrator,
A moving body drive mechanism for moving the moving body along the first and second guide bars,
The moving body is held by the first guide bar so as to be movable in the axial direction and the axis of the first guide bar,
The moving body includes a pressurizing unit that pressurizes and contacts the contact portion of the vibrator with the second guide bar.
The vibrator is pressurized and biased to the second guide bar so that the rotational movement of the movable body around the first guide bar axis is restricted by the pressurizing means ,
The present invention relates to a drive mechanism for a moving body in which a contact area between a contact portion of the vibrator and the second guide bar is arranged so as to substantially coincide with a plane including a central axis of the first guide bar .
According to another aspect of the present invention, a movable body having at least an electro-mechanical energy conversion element and an elastic body on which a contact portion is formed is fixed, and the movable body is slidably held. A first guide bar and a second guide bar arranged in parallel, and between the second guide bar contacting the contact portion of the vibrator by applying a driving voltage to the electromechanical energy conversion element Generating a relative moving force, and moving the moving body along the first and second guide bars, wherein the moving body includes an axial direction and an axis of the first guide bar. While being held by the first guide bar so as to be able to move around, the moving body includes a pressurizing unit that pressurizes and contacts the contact portion of the vibrator with the second guide bar, and the pressurizing unit By the mobile body The vibrator is pressed and urged by the second guide bar so that the rotational movement around one guide bar axis is restricted, and the vibrator is opposed to the vibrator with the second guide bar interposed therebetween. A movable body drive comprising: a drop-off prevention portion provided, wherein the drop-off prevention portion is disposed with the gap between the second guide bar and the pressurizing means is a magnetic member. Regarding the mechanism.

According to the present invention, the frictional force caused by the frictional contact when the relative moving force is generated between the vibrator and the guide bar that is in frictional contact is not hindered, and the moving body is smoothly slid along the guide bar. it becomes possible to realize the driving mechanism can be a Do that moving body.

The perspective view explaining the structure of the drive mechanism of the moving body by the vibration type drive device in Example 1 of this invention. The perspective view explaining the structure of the holding | maintenance part vicinity in Example 1 of this invention. Sectional drawing of the drive mechanism of the moving body by the vibration type drive device in Example 1 of this invention. The perspective view explaining the structure of the drive mechanism of the moving body by the vibration type drive device in Example 2 of this invention. The perspective view explaining the structure of the holding | maintenance part vicinity in Example 2 of this invention.

The mode for carrying out the present invention will be described with reference to the following examples.
In the following description of the present embodiment, a configuration example of a driving mechanism of a moving body by a vibration type driving device that linearly moves a lens holding member (moving body) that holds a lens group in the optical axis direction will be described.
However, the present invention is not limited to such a configuration and can be widely applied as a linear motion application.
In the present invention, the terms “parallel” and “vertical” are used as terms defining the positional relationship, but “parallel” and “vertical” in the present invention are theoretically completely “parallel” and “vertical”. As well as a state that can be regarded as substantially “parallel” and “vertical”. The state that can be regarded as substantially “parallel” and “vertical” means a state in which the effects of the present invention are exhibited. According to the knowledge of the present inventors, the deviation of the angle from the theoretical values of “parallel” and “vertical” is preferably within 5 °, more preferably within 1 °.

[Example 1]
As a first embodiment, a configuration example of a moving body driving mechanism using a vibration type driving device to which the present invention is applied will be described with reference to FIG.
The driving mechanism of the moving body by the vibration type driving device of the present embodiment includes a moving body in which a vibrator having an electro-mechanical energy conversion element and an elastic body in which a contact portion is formed is fixed, and sliding the moving body. A first guide bar and a second guide bar, which are freely held and are arranged in parallel, are provided.
Then, due to the elliptical motion of the contact portion of the vibrator generated by the application of the drive voltage to the electro-mechanical energy conversion element, the relative movement is made between the vibrator and the second guide bar contacting the contact portion of the vibrator. Generate power.
Thus, the movable body is configured to be movable along the first and second guide bars.
Specifically, as shown in FIG. 1, the moving body driving mechanism 100 by the vibration type driving device of this embodiment mainly includes a lens holder 2, a lens group 7, a vibrator 1, a pressure magnet 5, It comprises guide bars 3 and 4 and a base (not shown).
The first guide bar 3 and the second guide bar 4 constituted by two guide bars are both held and fixed by a base (not shown) so that both ends of each guide bar are arranged in parallel to each other. .
The vibrator 1 is formed by integrally joining a plate-like diaphragm (elastic body) 11 made of metal and an electromechanical energy conversion element 12.
The lens holder 2 includes a cylindrical holder portion 2a, a holding portion 2b that holds and fixes the vibrator 1 and the pressing magnet 5, and a first guide portion 2c that engages with the first guide bar 3 to act as a guide. Composed.
The two contact portions 11a of the vibrator 1 are in pressure contact with the second guide bar 4 to form a second guide portion.

Next, the configuration in the vicinity of the holding portion 2b of the lens holder (lens holding member) 2 that holds the lens constituting the moving body in this embodiment will be described with reference to FIG.
In the present embodiment, the pressing magnet 5 is held and fixed on the upper surface of the holding portion 2b.
The pressurizing magnet (magnetic member) 5 for constituting the pressurizing means is composed of a permanent magnet 52 and two yokes 51 disposed at both ends of the permanent magnet 52.
The permanent magnet 52 is magnetized in the direction of the arrow described on the permanent magnet 52 in the figure.
Two elastic members 62 are disposed in the holding portion 2b. Both ends of each elastic member 62 are fixed to the holding portion 2b, and the vibrator fixing member 61 is fixed near the center of each elastic member 62.
The support portion 11 b of the vibrator 1 is fixed to the upper surfaces of the two vibrator fixing members 61.

The vibrator 1 is fixed to the holding portion 2b via two elastic members 62, and the vibrator 1 has a degree of freedom so that the two contact portions 11b of the vibrator 1 follow the guide bar 4. Is given.
By holding the vibrator 1 in this manner, a function for compensating for a decrease in contact accuracy with the guide bar 4 caused by component accuracy or the like is provided.
A magnetic circuit is formed between the pressurizing magnet 5 and the guide bar 4, and an attractive force is generated between these members. The pressurizing magnet 5 is disposed at a distance from the guide bar 4, and the guide bar 4 is disposed in contact with the vibrator 1.
A pressing force is applied between the guide bar 4 and the vibrator 1 by the suction force. The guide bar 4 and the vibrator 1 form a second guide part.

The second guide portion forms a guide mechanism using an attractive force by magnetism, and the vibrator 1 and the guide bar 4 are separated by receiving an external force or the like. Have been dealt with.
That is, the lens holder 2 is returned to a desired position when the drop prevention portion 2d provided in the lens holder 2 hits the guide bar.
By applying a desired electrical signal to the vibrator 1, a driving force is generated between the vibrator 1 and the guide bar 4, and the lens holder is driven by this driving force.
Note that the structure and operation of a vibrator that generates an elliptical motion at the contact portion of the vibrator by applying a driving voltage to the electro-mechanical energy conversion element is disclosed in detail in many documents such as JP-A-2005-354787. These descriptions are omitted here.

FIG. 3 shows a cross-sectional view of the vibration type driving device 1 in a plane including the vibrator 1 and orthogonal to the lens optical axis direction.
The first guide part is constituted by a cylindrical guide bar 3 and a guide part 2c having a cylindrical hole in contact with the guide bar 3, and the lens holder 2 has a Z direction and a central axis P1 around the guide bar 3. Degrees of freedom θz.
The position of the vibrator 1 is determined so that the contact surface in contact with the second guide bar 4 coincides with a plane including the central axis P1.
The guide bar 4 is fixed at a position that follows the contact surface of the vibrator 1, and the rotation of the lens holder 2 around the central axis P1 is restricted by the second guide portion.
These first and second guide portions give the lens holder only freedom in the Z direction, so that the lens group is moved only in the optical axis direction.

In the present embodiment, the vibrator is pressure-biased by the second guide bar so that the rotational movement of the movable body around the first guide bar axis is regulated by the pressurizing means.
And the structure which prescribes | regulates the position of a vibrator | oscillator is taken so that the contact surface which contact | connects the 2nd guide bar 4 of the vibrator | oscillator 1 may correspond on the plane containing the central axis P1 as mentioned above. However, the present invention is not limited to such a configuration, and the contact area between the contact portion of the vibrator and the second guide bar is perpendicular to the plane including the axes of the first and second guide bars. What is necessary is just to be comprised so that it may become a predetermined angle except an angle.
For example, each component fixed on the holding portion 2b may be arranged at a position rotated around the axis of the guide bar 4.
Accordingly, since it is sufficient that the rotation around the central axis P1 can be defined as the second guide portion, the contact area between the contact portion of the vibrator and the second guide bar becomes a plane including the axes of the first and second guide bars. On the other hand, it acts as the second guide part except for the orthogonal state.
According to the configuration of the present embodiment described above, it is possible to achieve both the securing of the frictional force for moving the vibrator and the second guide bar relative to each other and the smooth sliding of the lens holder with respect to the guide bar. It becomes possible.

[Example 2]
As a second embodiment, a configuration example of a moving body driving mechanism using a vibration type driving device having a different form from the first embodiment will be described with reference to FIGS. 4 and 5.
As shown in FIG. 4, reference numeral 100 denotes a moving body driving mechanism by the vibration type driving apparatus of this embodiment. Hereinafter, the description of the same configuration as that of the first embodiment will be omitted.

A configuration in the vicinity of the holding portion 2b of the lens holder 2 in the present embodiment will be described with reference to FIG.
One contact portion 11a is formed at the center of the upper surface of the vibrator 11 to come into contact with the guide bar 4 and generate relative movement therebetween.
Two support portions 11b of the vibrator 1 are directly fixed to the holding portion 2b of the lens holder.
In this embodiment, since the contact portion 11a of the vibrator 1 is one place, the contact state between the vibrator 1 and the guide bar 4 is good even if an inclination caused by component accuracy or assembly accuracy occurs. Can maintain a good condition.

DESCRIPTION OF SYMBOLS 1: Vibrator 2: Lens holder 3: Guide bar 4: Guide bar 5: Pressurizing magnet 7: Lens group 100: Driving mechanism of moving body by vibration type driving device

Claims (9)

A moving body to which a vibrator having at least an electro-mechanical energy conversion element and an elastic body on which a contact portion is formed is fixed;
A first guide bar and a second guide bar arranged in parallel to hold the movable body slidably,
By applying a driving voltage to the electro-mechanical energy conversion element, a relative moving force is generated between the second guide bar and the contact portion of the vibrator,
A moving body drive mechanism for moving the moving body along the first and second guide bars,
The moving body is held by the first guide bar so as to be movable in the axial direction and the axis of the first guide bar,
The moving body includes a pressurizing unit that pressurizes and contacts the contact portion of the vibrator with the second guide bar.
The vibrator is pressurized and biased to the second guide bar so that the rotational movement of the movable body around the first guide bar axis is restricted by the pressurizing means ,
A drive mechanism for a moving body , wherein a contact area between the contact portion of the vibrator and the second guide bar is arranged so as to substantially coincide with a plane including a central axis of the first guide bar .   The drive mechanism of the moving body according to claim 1, wherein a contact area between the contact portion of the vibrator and the second guide bar is one. The drive mechanism for a moving body according to claim 1 or 2 , wherein the pressurizing means is constituted by a magnetic member. The driving mechanism for a moving body according to any one of claims 1 to 3 , wherein the moving body is configured by a lens holding member that holds a lens. By applying a driving voltage to the electromechanical energy conversion element, an elliptical motion is generated at the contact portion of the vibrator, and the relative movement between the contact portion of the vibrator and the second guide bar is caused by the elliptical motion. The driving mechanism for a moving body according to any one of claims 1 to 4, wherein a force is generated. A moving body to which a vibrator having at least an electro-mechanical energy conversion element and an elastic body on which a contact portion is formed is fixed;
A first guide bar and a second guide bar arranged in parallel to hold the movable body slidably,
By applying a driving voltage to the electro-mechanical energy conversion element, a relative moving force is generated between the second guide bar and the contact portion of the vibrator,
A moving body drive mechanism for moving the moving body along the first and second guide bars,
The moving body is held by the first guide bar so as to be movable in the axial direction and the axis of the first guide bar,
The moving body is configured with a magnetic pressure unit that pressurizes and contacts the contact portion of the vibrator with the second guide bar,
The vibrator is pressurized and biased to the second guide bar so that the magnetic pressing means regulates the rotational movement of the movable body around the first guide bar axis,
Having a drop-off prevention part provided so as to face the vibrator with the second guide bar interposed therebetween;
The drive mechanism for a moving body, wherein the drop-off prevention unit is disposed with the second guide bar and a gap therebetween. The drive mechanism of the moving body according to claim 1, wherein a contact area between the contact portion of the vibrator and the second guide bar is one. 8. The driving mechanism for a moving body according to claim 6, wherein the moving body is constituted by a lens holding member that holds a lens. By applying a driving voltage to the electromechanical energy conversion element, an elliptical motion is generated at the contact portion of the vibrator, and the relative movement between the contact portion of the vibrator and the second guide bar is caused by the elliptical motion. The driving mechanism for a moving body according to any one of claims 6 to 8, wherein a force is generated.

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