JP3681541B2 - Micro-rotation drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a minute rotation driving device that rotationally drives a member by a minute angle.
[0002]
[Prior art]
Such a minute rotation driving device is used, for example, for the purpose of rotating an optical element in an optical system by a minute angle.
[0003]
Such a micro-rotation driving device is disclosed in, for example, Japanese Patent No. 2537277. The micro-rotation driving device disclosed in Japanese Patent No. 2537277 is used in a scanning optical system used for an image drawing apparatus to rotate a Pechan prism by a micro angle for the purpose of rotating an image. There is a configuration in which a pair of piezo elements is applied to a rectangular rotating body pulled at its four corners by a leaf spring to cause rotational displacement about the virtual center to the rotating body. Have
[0004]
[Problems to be solved by the invention]
Such a conventional micro-rotation driving device requires a driving means such as a pair of piezo elements in order to obtain a rotational displacement, resulting in a problem that the configuration becomes complicated.
[0005]
Further, since the rotating body is pulled by the leaf springs at its four corners, a large force is required to rotate the rotating body. For this reason, it becomes difficult to maintain the linearity of the displacement due to the deformation of the rotating body, the piezo element, and the like, and there arises a problem that accurate rotational driving cannot be performed.
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a micro-rotation driving device that can obtain accurate micro-rotation driving with a simple configuration.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a micro-rotation drive device comprising: a rotary member rotatable about a central axis; and one end of the rotary member rotatably connected to a fixed member, and the other end connected to the rotary member and a first hinge. A connecting member connected via a portion, a driving means for pressing the connecting member in a rotating direction of the connecting member, and the fixing member or the central axis, the fixing member and the central axis being separated from each other It is characterized by comprising tension applying means for applying tension to the first hinge part by moving in the direction.
[0008]
According to a second aspect of the present invention, there is provided the micro-rotation driving device according to the first aspect, wherein the connecting member is connected to the fixing member via a second hinge portion, and the tension applying means is Tension is applied to the first hinge portion and the second hinge portion.
[0009]
According to a third aspect of the present invention, in the minute rotation driving device according to the first or second aspect, the tension applying unit moves the fixing member in a direction away from the central axis. ing.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view of a micro-rotation drive device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the main part thereof, and FIG. 3 is a schematic front view thereof.
[0011]
The minute rotation drive device includes a rotation member 2 having a central shaft 1, a fixing member 5 fixed to a base portion 9 (part of which is shown in FIG. 1) for installing the minute rotation drive device, and these The connecting member 3 for connecting the rotating member 2 and the fixing member 5 and a piezo element 7 for pressing the connecting member 3 are provided. The rotating member 2, the fixing member 5, and the connecting member 3 are integrally formed of metal such as tool steel.
[0012]
The central shaft 1 of the rotating member 2 is rotatably supported by a bearing (not shown) installed on the base portion 9 on which the minute rotation driving device is installed. The central axis 1 is connected to an optical element to be rotationally driven in an optical system such as the above-described Pechan prism.
[0013]
The fixing member 5 is fixed to the base portion 9 by a pair of screws 17 that pass through the through-hole 18 (see FIG. 2) and are screwed into screw holes formed in the base portion 9 where the micro-rotation driving device is installed. ing. The inner diameter of the through hole 18 formed in the fixing member 5 is larger than the outer shape of the screw 17, and the fixing member 5 can move in a direction away from the central axis 1 by the action of the wedge member 8. ing.
[0014]
More specifically, an inclined surface 16 (see FIG. 3) is formed at one end of the fixing member 5, and an inclined surface 15 that contacts the inclined surface 16 is formed on the wedge member 8. . For this reason, if the wedge member 8 is pressed from above by a pair of screws 14, the inclined surface 16 of the fixing member 5 is pressed by the inclined surface of the wedge member 8, and the fixing member 5 moves away from the central axis 1. Will move.
[0015]
The connecting member 3 and the rotating member 2 are connected via the first hinge part 4. The first hinge portion 4 is formed by forming the metal constituting the first hinge portion 4 so as to have a thickness of about 0.2 mm, thereby bending the connecting member 3 and the rotating member 2 with an elastic force. It is to be connected in a state to obtain. That is, this 1st hinge part 4 comprises the elastic hinge of the leaf | plate spring structure using a metal thin plate. For this reason, the rotating member 2 is connected to the connecting member 3 so as to be rotatable.
[0016]
Similarly, the connecting member 3 and the fixing member 5 are connected via the second hinge portion 6. The second hinge portion 6 also bends the connecting member 3 and the fixing member 5 with an elastic force by forming the metal constituting the second hinge portion 6 so as to have a thickness of about 0.2 mm. It is to be connected in a state to obtain. That is, the second hinge portion 6 also constitutes an elastic hinge having a leaf spring structure using a thin metal plate. For this reason, the connecting member 3 is rotatably connected to the fixing member 5.
[0017]
One end of the piezo element 9 is fixed to the base portion 9, and the other end is in contact with a sphere 12 disposed in the recess 11 of the connecting member 3. For this reason, the piezo element 9 functions as a driving unit that presses the connecting member 3 in the rotating direction of the connecting member 3 with respect to the fixing member 5.
[0018]
In the micro-rotation driving device having the above-described configuration, the inclined surface 16 of the fixing member 5 is pressed by the inclined surface 15 of the wedge member 8, and the fixing member 5 is moved away from the central axis 1. After applying tension to the first hinge part 4 and the second hinge part 6, the fixing member 5 is fixed to the base part 9 with the screw 17. In this state, the end of the piezo element 7 in the contracted state opposite to the contact portion with the base portion 9 is in contact with the sphere 12 disposed in the recess 11 of the connecting member 3. The piezo element 7 is disposed.
[0019]
In such a state, by applying a voltage to the piezo element 7, the sphere 12 is pressed by driving the piezo element 7. With the pressing force by the piezo element 7, the connecting member 3 is rotated by a minute angle in the clockwise direction in FIG. 1 about the bending position in the second hinge portion 6. Then, the first hinge portion 4 moves with the rotation of the connecting member 3, and is connected to the connecting member 3 via the first hinge portion 4 with the movement of the first hinge portion 4. The rotating member 2 rotates about the central axis 1 by a minute angle in the counterclockwise direction shown in FIG.
[0020]
At this time, the rotating member 2 and the fixing member 5 are connected to the connecting member 3 by the first hinge portion 4 and the second hinge portion 6 formed by processing metal into a thin plate shape, and thus are small. The rotating member 2 can be easily rotated by the driving force.
[0021]
When the pressing force by the piezo element 7 is released, the rotating member 2 rotates counterclockwise by the tension generated by the action of the wedge member 8 and returns to the original angular position.
[0022]
In the micro-rotation driving device having such a configuration, if the metal thin plate portions constituting the first hinge portion 4 and the second hinge portion 6 are made thin, the rotating member 2 is rotated with a smaller driving force. In addition, the bending stress acting on the first hinge part 4 and the second hinge part 6 is relaxed, and the durability of the first hinge part 4 and the second hinge part 6 is improved. On the other hand, when the first hinge portion 4 and the second hinge portion 6 are thinned, the rigidity thereof is lowered, and there is a problem that the first hinge portion 4 and the second hinge portion 6 are easily affected by external vibrations.
[0023]
However, in the micro-rotation drive device described above, tension is applied to the first hinge portion 4 and the second hinge portion 6 by the action of the wedge member 8, so that the first hinge portion 4 and the second hinge portion 6 Even when the thickness of the hinge portion 6 is reduced, the rigidity of the first hinge portion 4 and the second hinge portion 6 can be improved by the stress hardening effect, and the influence of external vibration or the like can be reduced. It becomes possible to prevent.
[0024]
Further, even in the case where vibration that causes resonance occurs outside the micro-rotation drive device, the pressing force of the screw 14 against the wedge member 8 is adjusted and applied to the first and second hinge portions 4 and 6. By adjusting the applied tension, it is possible to change the eigenvalues of vibrations for the rotating member 2, the connecting member 3, the fixed member 5, etc., thereby preventing the occurrence of resonance.
[0025]
As shown in FIG. 1, the distance between the bending position of the second hinge portion 6 and the bending position of the first hinge portion 4 is a, the bending position of the second hinge portion 6, the piezo element 7 and the sphere 12. If the distance to the contact position is b and the movement amount of the sphere 12 by the piezo element 7 is c, the second hinge part 4 moves by d = c × (a / b). For this reason, even when the same piezo element 7 is used, it is possible to change the rotation angle by the minute rotation driving device by changing the values of a and b described above.
[0026]
Next, another embodiment of the present invention will be described. FIG. 4 is a schematic plan view of a minute rotation driving device according to the second embodiment of the present invention. In addition, about the member same as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
[0027]
In the micro-rotation drive device according to the first embodiment described above, the rotary member 2 is rotated using the pressing force of the piezo element 7 and the tension generated by the wedge member 8, or returned to the original angular position. However, in the second embodiment, a spring 13 that further presses the connecting member 3 in a direction opposite to the pressing direction of the connecting member 3 by the piezo element 7 is further disposed at a position facing the piezo element 7. The rotating member 2 is returned to the original angular position by the pressing force of 13.
[0028]
In the micro-rotation driving device according to the second embodiment, the end of the piezo element 7 in the contracted state is pressed by the spring 13 and the end opposite to the contact portion with the base portion 9 (in FIG. 4). The piezo element 7 is arranged so that the sphere 12 arranged in the recess 11 of the connecting member 3 in a state indicated by a one-point difference line abuts.
[0029]
In such a state, by applying a voltage to the piezo element 7, the sphere 12 is pressed by driving the piezo element 7. With the pressing force by the piezo element 7, the connecting member 3 rotates about a bending position in the second hinge portion 6 by a small angle in the clockwise direction in FIG. 4. Then, the first hinge portion 4 moves with the rotation of the connecting member 3, and is connected to the connecting member 3 via the first hinge portion 4 with the movement of the first hinge portion 4. The rotating member 2 rotates from the position indicated by the one-point difference line in FIG. 4 to the position indicated by the two-point difference line in FIG. 4 beyond the position indicated by the solid line in FIG.
[0030]
Further, when the pressing force by the piezo element 7 is released, the rotating member 2 rotates counterclockwise by the pressing force by the spring 13 and returns to the original angular position indicated by a one-point difference line in FIG.
[0031]
In both the first and second embodiments described above, the fixing member 5 is pressed by the wedge member 8 having the inclined surface 15 that comes into contact with the inclined surface 16 formed on the fixing member 5. 5 is moved in a direction away from the central axis 1, but the fixing member 5 may be directly pressed by a screw or the like to move the fixing member 5 in a direction away from the central axis 1.
[0032]
In both the first and second embodiments described above, the first hinge portion 4 and the second hinge portion 6 are moved by moving the fixing member 5 away from the central axis 1. Although tension is applied, the configuration may be such that tension is applied to the first hinge part 4 and the second hinge part 6 by moving the central shaft 1 in a direction away from the fixing member 5.
[0033]
In both the first and second embodiments described above, the central shaft 1 that is rotatably supported by a bearing (not shown) disposed on the base portion 9 on which the micro-rotation driving device is installed, Although it has the structure fixed with respect to the rotation member 2, as a structure which fixes the center axis | shaft 1 on the base part 9 which installs a micro rotation drive device, and rotates the rotation member 2 with respect to the center axis | shaft 1. Good. In this case, since only the rotating member 2 rotates, the optical element to be rotationally driven in the optical system such as the above-described Pechan prism is connected to the rotating member 2.
[0034]
In both the first and second embodiments described above, the connecting member 3 and the fixing member 5 are connected via the second hinge portion 6, but one end of the connecting member 3 is connected to the other. It is good also as a structure connected so that it can rotate with respect to the fixing member 5 by this rotation connection mechanism.
[0035]
Furthermore, in both the first and second embodiments described above, the piezo element 7 is used as a driving means for pressing the connecting member 3 in the rotating direction. However, other electrostrictive elements and magnetostrictive elements are used. An element may be used.
[0036]
【The invention's effect】
According to the first aspect of the present invention, the rotating member that is rotatable about the central axis, one end of the rotating member is rotatably connected to the fixed member, and the other end is connected to the rotating member and the first hinge portion. The connecting member connected via the connecting member, the driving means for pressing the connecting member in the rotational direction of the connecting member, and the fixing member or the central shaft moving in the direction in which the fixing member and the central shaft are separated from each other. Since the tension applying means for applying tension to the hinge portion is provided, the rotation member can be rotated by a small angle with a small driving force while simplifying the configuration of the entire apparatus, and an accurate minute rotation drive is obtained. It becomes possible.
[0037]
According to the second aspect of the present invention, the connecting member is connected to the fixing member via the second hinge portion, and the tension applying means applies tension to the first hinge portion and the second hinge portion. Therefore, the configuration of the entire apparatus can be simplified, and the rotating member can be rotated by a small angle with a smaller driving force.
[0038]
According to the third aspect of the invention, since the tension applying means moves the fixing member in the direction away from the central axis, it is possible to apply the tension without changing the position of the rotation center, and to rotate. Positioning work for the power member becomes unnecessary.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a minute rotation driving device according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a main part of the minute rotation driving device according to the first embodiment of the present invention.
FIG. 3 is a schematic front view of the minute rotation driving device according to the first embodiment of the present invention.
FIG. 4 is a schematic plan view of a minute rotation driving device according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Center axis 2 Rotating member 3 Connecting member 4 1st hinge part 5 Fixing member 6 2nd hinge part 7 Piezo element 8 Wedge member 9 Base part 11 Recess 12 Sphere 13 Spring 14 Screw 15 Inclined surface 16 Inclined surface 17 Screw 18 Hole

Claims (3)

A rotating member rotatable about a central axis;
One end of which is rotatably connected to the fixed member, and the other end is connected to the rotating member via the first hinge part,
Drive means for pressing the connecting member in the rotating direction of the connecting member;
Tension applying means for applying tension to the first hinge portion by moving the fixing member or the central axis in a direction in which the fixing member and the central axis are separated from each other;
A micro-rotation drive device characterized by comprising: The minute rotation driving device according to claim 1,
The connecting member is connected to the fixing member via a second hinge portion, and the tension applying means applies a tension to the first hinge portion and the second hinge portion. In the minute rotation drive device according to claim 1 or 2,
The tension applying means is a micro-rotation driving device that moves the fixing member in a direction away from the central axis.

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