Drive unit

Abstract

To provide a driving device that can be prevented from breaking.SOLUTION: A base member 4 includes: a frame part 41 for rotatably supporting a movable part by an axial part provided on the inner periphery side; and an elastic structure part 42 extending to the outer periphery side of the frame part. The elastic structure part 42 of the base member 4 is joined to a pedestal 7 so that the difference of the heat deformation amount that happened in the base member 4 and happened in the pedestal 7 can be absorbed by the deformation of the elastic structure part 42, which makes it possible to suppress breakage of the drive device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] Conventionally, a magnetic force type driving device has been proposed in which a movable plate is rotatably supported by a pair of beams on a frame body and a yoke is provided near a permanent magnet, thereby rotating the movable plate (see, for example, Patent Document 1). In the magnetic force type driving device described in Patent Document 1, the oscillation angle of the movable part is increased by conducting current through a coil wound around the yoke so that different magnetic poles appear at the pair of ends of the yoke. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-246362 Summary of the Invention [Problem to be solved by the invention]

[0004] In the drive device described in Patent Document 1, a frame body is disposed on a yoke. That is, in order to stably rotate the movable plate, the frame body (base member) needs to be fixed to some kind of pedestal. However, while the base member is often made of the same material as the movable part, the pedestal may be made of a different material from the base member, and these materials may have different thermal expansion coefficients.

[0005] In this case, when heat is applied to the drive unit, the difference in the amount of thermal deformation between the pedestal and the base member can cause large stresses to be applied to the joint between them and to the base member itself, which could lead to damage.One possible solution is to increase the amount of adhesive used at the joint to absorb the difference in the amount of thermal deformation, but increasing the amount of adhesive increases the impact of cure shrinkage during adhesion, making it more likely that stress will be applied to the joint between the pedestal and the base member and to the base member itself.

[0006] Therefore, an object of the present invention is to provide a drive device that can suppress damage, for example. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the driving device of the present invention described in claim 1 comprises a movable part, a base member having a frame-shaped part and rotatably supporting the movable part by an axis part provided on the inner periphery of the frame-shaped part, a driving means for driving the movable part, and a pedestal to which the base member is fixed, wherein the base member has an elastic structure part extending toward the outer periphery of the frame-shaped part in the in-plane direction of the plane in which the frame-shaped part extends, and the elastic structure part is joined to the pedestal. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a drive device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view showing the drive device. [Figure 3] FIG. 10 is an exploded perspective view showing a state in which a support member is provided in the drive device. [Figure 4] FIG. 2 is a side view showing the drive device. [Figure 5] FIG. 10 is a perspective view showing a drive device according to a second embodiment of the present invention. [Figure 6] FIG. 2 is an exploded perspective view showing the drive device. [Figure 7] FIG. 10 is an exploded perspective view showing a state in which a support member is provided in the drive device. [Figure 8] FIG. 2 is a side view showing the drive device. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below. A drive device according to an embodiment of the present invention includes a movable part, a base member having a frame-shaped part and rotatably supporting the movable part by a shaft provided on the inner periphery of the frame-shaped part, a drive means for driving the movable part, and a pedestal to which the base member is fixed. The base member has an elastic structure extending on the outer periphery of the frame-shaped part, and the elastic structure is joined to the pedestal.

[0010] By joining the elastic structural portion of the base member to the pedestal, the difference in the amount of thermal deformation between the base member and the pedestal can be absorbed by the deformation of the elastic structural portion, thereby suppressing damage to the base member and the connection portion between the shaft portion and the base member. In this case, the elastic structural portion may be a portion having a shape that is more easily elastically deformed than the frame-shaped portion.

[0011] The elastic structure preferably has an orthogonal portion that extends perpendicular to the frame-shaped portion. This allows the elastic structure to be easily formed by simply forming the orthogonal portion so that it protrudes outward from the frame-shaped portion.

[0012] The elastic structure may have a parallel portion extending along the frame portion. This prevents the base member from becoming large even if the dimension of the parallel portion is increased along the frame portion, and makes it easier to absorb differences in the amount of thermal deformation. Note that the orthogonal portion and the parallel portion may be combined.

[0013] The frame-shaped portion may not be joined to the base, or only a portion of the frame-shaped portion may be joined to the base. That is, the joining area of ​​the base member may be set so as to achieve an appropriate balance between the joining strength between the base member and the base and the ease of deformation of the elastic structure.

[0014] It is preferable that the joining members for joining the elastic structures to the base are disposed at a plurality of locations corresponding to the plurality of elastic structures, thereby reducing the amount of joining members used.

[0015] The elastic structure preferably has a non-bonded portion that is continuous with the frame-shaped portion and not bonded to the base, and a bonded portion that is continuous with the non-bonded portion and bonded to the base, which makes it easier to elastically deform the non-bonded portion and reduces stress applied to the frame-shaped portion and the bonded portion due to the difference in thermal deformation between the base member and the base. [Example]

[0016] Each embodiment of the present invention will be specifically described below. In the second embodiment, the same components as those described in the first embodiment and components having similar functions will be assigned the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted.

[0017] [First Example] 1 to 4, the driving device 1A of this embodiment is an optical deflector including a mirror 2, an intermediate frame 3, a base member 4, an inner torsion bar 5, an outer torsion bar 6, a base 7, and a driving means. The driving device 1A is used in a detection device that is mounted on a vehicle and detects the distance to another vehicle, an installed object, etc. by transmitting and receiving light such as infrared light.

[0018] In this embodiment, the inner torsion bar 5 and the outer torsion bar 6 extend approximately perpendicular to each other, the extension direction (axial direction) of the inner torsion bar 5 is the X direction, the extension direction (axial direction) of the outer torsion bar 6 is the Y direction, and the direction approximately perpendicular to the XY plane is the Z direction.

[0019] The mirror 2 is formed in the shape of a plate extending along the XY plane, and its surface 21 is mirror-finished to form a reflective surface. A pair of inner torsion bars 5 is connected to the outer periphery of the mirror 2. Although the mirror 2 is shown as being disk-shaped in the illustrated example, the mirror 2 may be an elliptical plate, a polygonal plate such as a rectangular plate, or any other suitable shape depending on the application.

[0020] The intermediate frame 3 is formed in the shape of a rectangular frame extending along the XY plane, and is disposed so as to surround the mirror 2. A pair of inner torsion bars 5 is connected to the inner periphery of the intermediate frame 3, and a pair of outer torsion bars 6 is connected to the outer periphery. In other words, the mirror 2 is rotatably supported by the intermediate frame 3 via the inner torsion bars 5.

[0021] The base member 4 has a rectangular frame portion 41 that extends along the XY plane and surrounds the intermediate frame 3, and a plurality of elastic structures 42 that extend on the outer periphery of the frame portion 41. A pair of outer torsion bars 6 are connected to the inner periphery of the base member 4. In other words, when the mirror 2, intermediate frame 3, and inner torsion bar 5 form a movable part, the movable part is rotatably supported by the base member 4 via the outer torsion bar 6 that serves as an axis.

[0022] The frame-shaped portion 41 is configured with a first side portion 411 and a second side portion 412 extending along the X direction, and a third side portion 413 and a fourth side portion 414 extending along the Y direction. Each of the multiple elastic structures 42 extends along the Y direction, continuing from the first side portion 411 or the second side portion 412, and extends along the X direction, continuing from the third side portion 413 or the fourth side portion 414. In other words, the entire elastic structure 42 forms an orthogonal portion 421 that extends perpendicular to the frame-shaped portion 41. Because the entire elastic structure 42 is the orthogonal portion 421, it is easier for the elastic structure 42 to elastically deform than the frame-shaped portion 41.

[0023] The mirror 2, intermediate frame 3, base member 4, inner torsion bar 5, and outer torsion bar 6 are integrally formed on a substrate made of, for example, Si, to form a mirror unit 10.

[0024] The pedestal 7 is made of a material such as an aluminum alloy or resin, has higher rigidity than the base member 4, and may have a thermal expansion coefficient different from that of the base member 4. The pedestal 7 is formed in the shape of a rectangular frame extending along the XY plane. In this embodiment, the inner opening of the frame-shaped portion 41 and the inner opening of the pedestal 7 are approximately aligned. The pedestal 7 may have any appropriate shape according to, for example, the shape of the base member 4 or the shape of the object to which the drive unit 1A is attached.

[0025] The driving means is for driving (rotating) the mirror 2 and the intermediate frame 3. The driving method of the driving means is not limited, and may be configured, for example, by a coil and a magnetic element, or by a piezoelectric element.

[0026] Here, the joining structure of the base member 4 to the pedestal 7 will be described in detail. The pedestal 7 is provided with joining members 8 at multiple locations corresponding to the respective tip ends 422 of the elastic structure 42. The elastic structure 42 is joined to the pedestal 7 by hardening the joining members 8. Note that the joining member 8 is preferably an acrylic adhesive, an epoxy adhesive, a permanent film resist, or the like, which retains elasticity even after hardening, but is not limited to these.

[0027] At this time, a tip end 422 of the elastic structure 42 corresponding to the joining member 8 becomes a joining portion joined to the base 7, and a base end 423 corresponding to a position where the joining member 8 is not provided becomes a non-joint portion not joined to the base 7. At this time, the base end 423 is continuous with the frame-shaped portion 41, and the tip end 422 is continuous with the base end 423. In addition, the frame-shaped portion 41 is not joined to the base 7 (the frame-shaped portion 41 does not have a joining portion).

[0028] When fixing the base member 4 to the pedestal 7 as described above, it is preferable to provide a support member 9 to position the base member 4 and the pedestal 7 in the Z direction. The support member 9 is formed in a frame shape to correspond to the frame-shaped portion 41, and is disposed more inward than the joining member 8. Note that the shape of the support member 9 is not limited to a frame shape, as long as it is disposed so that at least a portion of the support member 9 abuts against the frame-shaped portion 41. This makes it possible to prevent the base member 4 from coming too close to the pedestal 7 or from tilting before the joining member 8 hardens.

[0029] With the above configuration, the elastic structure 42 of the base member 4 is joined to the pedestal 7, so that the difference in the amount of thermal deformation that occurs between the base member 4 and the pedestal 7 can be absorbed by the deformation of the elastic structure 42, thereby suppressing damage to the base member 4 and the joint between the base member 4 and the pedestal 7.

[0030] Furthermore, since the entire elastic structure 42 is the orthogonal portion 421, it is sufficient to form the orthogonal portion 421 so as to protrude outward from the frame-shaped portion 41, and the elastic structure 42 can be easily formed.

[0031] Furthermore, the joining members 8 that join the elastic structure 42 to the base 7 are arranged in multiple locations to correspond to each of the multiple elastic structure parts 42, thereby reducing the amount of joining members 8 used.

[0032] Since the elastic structure 42 has a tip portion 422 as a joint portion and a base portion 423 as a non-joint portion, the base portion 423 can be easily elastically deformed, and the stress applied to the frame portion 41 and the joint portion due to the difference in the amount of thermal deformation occurring between the base member 4 and the pedestal 7 can be reduced.

[0033] [Second Example] 5 to 8, the driving device 1B of this embodiment is an optical deflector including a mirror 2, an intermediate frame 3, a base member 4B, an inner torsion bar 5, an outer torsion bar 6, a pedestal 7, and a driving means. That is, the driving device 1B is obtained by replacing the base member 4 of the driving device 1A of the first embodiment with a base member 4B.

[0034] The base member 4B has a frame-shaped portion 41 and eight elastic structures 43. The elastic structures 43 extend from the four corners of the frame-shaped portion 41. The elastic structures 43 have orthogonal portions 431 extending perpendicular to the frame-shaped portion 41 and parallel portions 432 extending along each side of the frame-shaped portion 41. That is, the elastic structures 43 protruding from the corners at both ends of the first side 411 of the frame-shaped portion 41 have orthogonal portions 431 extending along the Y direction and parallel portions 432 extending along the X direction outside the first side 411. The same applies to the elastic structures 43 protruding from the corners at both ends of each of the second to fourth sides 412 to 414. The elastic structures 43 may extend from positions on the sides of the frame-shaped portion 41 that are spaced apart from the outer torsion bar 6, or may extend from the three corners of the frame-shaped portion 41. By making the elastic structure portion 43 extend from a position on the frame-shaped portion 41 that is spaced apart from the outer torsion bar 6, the stress applied to the frame-shaped portion 41 due to the difference in the amount of thermal deformation occurring between the base member 4 and the pedestal 7 can be prevented from being transmitted to the base of the outer torsion bar 6.

[0035] The joining member 8 is provided corresponding to the tip end 432A of the parallel portion 432. That is, the tip end 432A is a joining portion that is joined to the base 7, and the base end 432B, which corresponds to a position where the joining member 8 is not provided, is a non-joint portion that is not joined to the base 7. The base end 432B is continuous with the frame-shaped portion 41, and the tip end 432A is continuous with the base end 432B. Furthermore, the frame-shaped portion 41 is not joined to the base 7 (the frame-shaped portion 41 does not have a joining portion).

[0036] As in the first embodiment, when the base member 4B is fixed to the pedestal 7, it is preferable to provide a support member 9 in order to position the base member 4B and the pedestal 7 in the Z direction.

[0037] With the above configuration, as in the first embodiment, the elastic structure 43 of the base member 4B is joined to the pedestal 7, so that the difference in the amount of thermal deformation occurring between the base member 4B and the pedestal 7 can be absorbed by the deformation of the elastic structure 43, thereby suppressing damage to the base member 4B and the joint between the base member 4B and the pedestal 7.

[0038] Furthermore, since the elastic structure 43 has the parallel portion 432, even if the dimensions of the parallel portion 432 are increased along each side of the frame-shaped portion 41, the base member 4B is less likely to become large, and differences in the amount of thermal deformation can be more easily absorbed.

[0039] The present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.

[0040] For example, in the first and second embodiments, the elastic structure has an orthogonal portion, but the elastic structure may have a portion that extends so as to intersect obliquely with the frame-shaped portion. Also, if the frame-shaped portion is annular, the orthogonal portion may be, for example, a portion of the elastic structure that is orthogonal to a tangent to the circle.

[0041] Furthermore, in the first and second embodiments, the frame-shaped portion 41 does not have a joint with the base 7, but a part of the frame-shaped portion may be joined to the base. For example, one side of the frame-shaped portion may be joined to the base, and the opposite side may be left unjoined, providing an elastic structure portion.

[0042] In the first and second embodiments, the joining members 8 are arranged at multiple locations corresponding to the multiple elastic structures, but a continuous joining member may also be provided. For example, the joining member may be provided in a ring shape according to the positions where the elastic structures are arranged.

[0043] Furthermore, in the first and second embodiments, the elastic structure has a joint portion and a non-joint portion, but in cases where the elastic structure is easily deformed, for example, when the elastic structure has sufficient thickness or when the deformation of the elastic structure is not easily hindered by the joint member, the entire elastic structure may be a joint portion (i.e., the elastic structure does not need to have a non-joint portion).

[0044] Furthermore, in the first and second embodiments, the mirror 2, the intermediate frame 3, and the inner torsion bar 5 constitute the movable part, and the movable part is rotatably supported by the base member 4 via the outer torsion bar 6 as an axis, but the mirror may be the movable part, and the mirror may be rotatably supported by the base member via the axis.

[0045] Although the best configurations and methods for carrying out the present invention have been disclosed above, the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described mainly with reference to specific embodiments, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Therefore, the above-disclosed descriptions limiting the shape, material, etc. are provided as examples to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, descriptions using names of components that are free from some or all of the limitations on shape, material, etc. are included in the present invention. [Explanation of symbols]

[0046] 1A, 1B drive unit 4, 4B Base material 41 Frame-shaped part 42, 43 Elastic structure 422 Tip (joint) 423 Base end (non-joined part) 431 Orthogonal section 432 Parallel section 7. Pedestal 8 Joint materials

Claims

1. A movable part; a base member having a frame-shaped portion and rotatably supporting the movable portion by a shaft portion provided on an inner circumferential side of the frame-shaped portion; a driving means for driving the movable part; a base to which the base member is fixed, the base member has an elastic structure portion extending toward an outer periphery of the frame portion in an in-plane direction of a plane in which the frame portion extends, A drive device characterized in that the elastic structure is joined to the base.

2. 2. The drive device according to claim 1, wherein the elastic structure has an orthogonal portion that extends perpendicular to the frame-shaped portion.

3. 3. The drive device according to claim 1, wherein the elastic structure has a parallel portion extending along the frame-shaped portion.

4. 4. The drive device according to claim 1, wherein the frame-shaped portion is not joined to the base.

5. A drive device as described in any one of claims 1 to 4, characterized in that joining members joining the elastic structure to the base are arranged at multiple locations corresponding to each of the multiple elastic structures.

6. A drive device as described in any one of claims 1 to 5, characterized in that the elastic structure has a non-bonded portion that is continuous with the frame-shaped portion and is not bonded to the base, and a bonded portion that is continuous with the non-bonded portion and bonded to the base.

7. The drive device according to any one of claims 1 to 6, characterized in that the base member having the frame-shaped portion, the shaft portion, and the elastic structure portion is integrally formed with the movable portion so as to form a single substrate.

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