Rotational reciprocating drive actuator and optical scanning device

Abstract

To provide a rotational reciprocating drive actuator which is easy to assemble, whose height is reduced, whose angle is widened and whose amplitude is increased and which can be driven.SOLUTION: A rotational reciprocating drive actuator comprises: a movable body which has a shaft part in which a magnet is fixed to the outer circumference, holds a V-shaped mirror in such a manner that a ridge line part of the V-shaped mirror is along the shaft part, and is supported in a reciprocating and rotatable manner around the shaft via the shaft part; and a unit body which includes: multiple magnetic poles that face the magnet in the radial direction of the shaft part and separate from each other in the peripheral direction of the shaft part, a coil body that forms an electromagnetic drive part that rotates the movable body in a reciprocating manner together with the magnet, and a magnetic element that is arranged between the magnetic poles in the peripheral direction so as to face the magnet in the radial direction of the shaft part and biases the movable body toward the initial position of the reciprocating rotation by suctioning the magnet. The electromagnetic drive part rotates the movable body in a reciprocating manner, and oscillates the V-shaped mirror while maintaining the angle formed by the V-shaped mirror.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotary reciprocating actuator and an optical scanning device. [Background technology]

[0002] Conventionally, rotary reciprocating actuators have been used as actuators for optical scanning devices such as multifunction peripherals, laser beam printers, etc. Specifically, rotary reciprocating actuators rotate the mirror of a scanner back and forth to change the reflection angle of a laser beam and realize optical scanning of an object.

[0003] Known examples of this type of rotary reciprocating actuator include those using a galvanometer motor as disclosed in Patent Document 1. Galvanometer motors include those with the structure disclosed in Patent Document 1, movable coil types in which a coil is attached to a mirror, and various other types.

[0004] Patent document 1 discloses a beam scanner in which four permanent magnets are provided on a rotating shaft to which a mirror is attached so as to be magnetized in the radial direction of the rotating shaft, and a core having magnetic poles around which a coil is wound is arranged on either side of the rotating shaft.

[0005] The beam scanner in Patent Document 1 has a configuration in which a magnet is arranged on the movable body side, i.e., a so-called moving magnet configuration, and unlike a coil-moving type rotary reciprocating drive actuator, heat generated by the coil during operation does not affect the movable body. In other words, in the movable body, heat generated by the coil does not adversely affect the mirror through the rotating shaft, etc., on the surface condition of the mirror, the bonding condition of the mirror to the rotating shaft, the shape of the mirror including warping, etc. Furthermore, when increasing the scanning angle of view to increase the amplitude of the mirror, unlike the moving coil type, there is no need to consider heat generated by the coil when current is applied, so this can be achieved by making the mirror larger and increasing the input current to the coil that moves it. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4727509 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional configuration, although it is possible to widen the angle, that is, to increase the amplitude, by making the mirror larger, the product itself becomes larger as the mirror becomes larger, making it difficult to reduce the height. Also, in the configuration of Patent Document 1, a four-pole magnet is used, which makes assembly complicated and difficult to assemble. In light of these circumstances, there is a demand in the field of scanners for a rotary reciprocating drive device that is easy to assemble, has high precision, has a wide angle, and can be driven at a high amplitude while being low in height.

[0008] The present invention has been made in consideration of the above points, and provides a rotary reciprocating actuator and an optical scanning device that are easy to assemble and can be driven while achieving a low profile, a wide angle, and a large amplitude. [Means for solving the problem]

[0009] One embodiment of the rotary reciprocating actuator of the present invention comprises: a movable body having a shaft portion with a magnet fixed to its outer periphery, holding a V-shaped mirror with a ridge portion of the V-shaped mirror aligned with the shaft portion, and supported so as to be rotatable back and forth around an axis via the shaft portion; a unit main body including: a plurality of magnetic poles facing the magnet in a radial direction of the shaft portion and spaced apart from one another in a circumferential direction of the shaft portion; a coil body forming, together with the magnet, an electromagnetic drive unit that rotates the movable body back and forth; and a magnetic body facing the magnet in the radial direction of the shaft portion and disposed between the plurality of magnetic poles in the circumferential direction, the magnetic body attracting the magnet and urging the movable body toward an initial position of the reciprocating rotation; having The electromagnetic drive unit is configured to rotate the movable body back and forth to oscillate the V-shaped mirror while maintaining the angle formed by the V-shaped mirror.

[0010] One aspect of the optical scanning device of the present invention is The rotary reciprocating actuator having the above configuration; a light irradiation unit that irradiates the V-shaped mirror of the rotary reciprocating actuator with a scanning light; The configuration has the following. Effect of the Invention

[0011] According to the present invention, the assembly is easy, and the actuator can be driven while achieving a low profile, a wide angle, and a high amplitude. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is an external perspective view of a rotary reciprocating actuator according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view passing through the axis of the rotary reciprocating actuator. [Diagram 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 4 is an exploded perspective view of the top surface side of the rotary reciprocating actuator according to one embodiment of the present invention. [Diagram 5] FIG. 5 is an exploded perspective view of the bottom side of the rotary reciprocating actuator. [Figure 6] FIG. 6 is a horizontal cross-sectional view showing the positional relationship between a mirror holding portion and a rotation shaft. [Figure 7] FIG. 7 is a diagram showing a magnetic circuit of a rotary reciprocating actuator according to one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram for explaining the operation of the magnetic circuit of the rotary reciprocating actuator. [Figure 9] FIG. 9 is a diagram for explaining an assembly structure of the rotary reciprocating actuator to a housing. [Figure 10]FIG. 10 shows the main configuration of a scanner system using the rotary reciprocating actuator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] Fig. 1 is an external perspective view of a rotary reciprocating actuator according to an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view passing through the axis of the rotary reciprocating actuator, Fig. 3 is a cross-sectional view taken along line BB in Fig. 2, Fig. 4 is an exploded perspective view of the upper surface side of the rotary reciprocating actuator, and Fig. 5 is an exploded perspective view of the lower surface side of the rotary reciprocating actuator.

[0015] <Overall configuration of rotary reciprocating actuator> The rotary reciprocating actuator 1 is used in, for example, a LiDAR (Laser Imaging Detection and Ranging) device. The rotary reciprocating actuator 1 can also be applied to optical scanning devices such as multifunction peripherals and laser beam printers.

[0016] The rotary reciprocating drive actuator 1 broadly comprises a V-shaped mirror 10, a drive unit 4 having a movable body 2 fixed to the V-shaped mirror 10, and a frame section 60 that supports the V-shaped mirror 10 via the drive unit 4. In the rotary reciprocating drive actuator 1, the drive unit 4 has a unit main body 40 including a core assembly 41 and constituting a fixed body, and the movable body 2, and the drive unit 4 is fixed to the frame section 60, and the movable body 2 has a rotating shaft 20 and a magnet (permanent magnet) 30 fixed to the rotating shaft 20.

[0017] The drive unit 4 includes an electromagnetic drive section including a coil body and a magnet 30 arranged in a core assembly 41, and the electromagnetic drive section rotates the movable body 2 back and forth to oscillate the V-shaped mirror while maintaining the angle formed by the V-shaped mirror.

[0018] The movable body 2 has a rotation shaft 20 with a magnet 30 fixed to its outer periphery, and holds the V-shaped mirror 10 with the ridge of the V-shaped mirror 10 aligned with the rotation shaft 20. The movable body 2 is supported by the unit main body 40 (as well as the frame portion 60 to which the unit main body 40 is fixed) via the rotation shaft 20 so as to be rotatable back and forth around the axis.

[0019] The V-shaped mirror 10 is supported so as to be rotatably driven back and forth relative to the frame portion 60 (specifically, a base portion 61) by a drive unit 4 fixed to the frame portion 60. The frame portion 60 has a plate-shaped base portion 61, a shaft holder 62, and bearings 64, 65, and together with the unit body 40 of the drive unit 4, constitutes a fixed body that supports the movable body 2 so as to be rotatably driven back and forth.

[0020] The components of the rotary reciprocating drive actuator 1, including the drive unit 4 and the frame portion 60, are assembled using fastening members 77, 81, 86a, etc. The fastening member 81 fixes the shaft holder 62 to the base portion 61. Note that the fastening members 77, 81, 86a may be used in any manner as long as they can fix the components to be connected, but it is preferable to fasten the connected objects to each other in the axial direction when assembling the drive unit 4, assembling the frame portion 60, or assembling the drive unit 4 and the frame portion 60.

[0021] That is, the components of the rotary reciprocating drive actuator 1 are fixed to each other by connection or joining in the axial direction. The fastening member may be, for example, a male thread such as a screw or a bolt or a nut, and may be composed of a fastening part and a fastened part that join objects to be joined by being inserted and screwed together in the axial direction.

[0022] The V-shaped mirror 10 is a movable object in the rotary reciprocating actuator 1, and is connected to a rotation axis 20. The V-shaped mirror 10 has two reflective surfaces 12a, 14a adjacent to each other along a ridge line parallel to the rotation axis 20. The V-shaped mirror 10 has a first mirror 12, a second mirror 14, and a mirror holder 16, and is formed by holding the first mirror 12 and the second mirror 14 by, for example, attaching them to the mirror holder 16. In the V-shaped mirror 10, a scanning line is irradiated onto the surfaces (reflective surfaces) 12a, 14a of the first mirror 12 and the second mirror 14, respectively. The V-shaped mirror 10 has a rotating shaft 20 inserted through and fixed to the insertion hole 162 of the mirror holding portion 16. The specific mounting positions of the V-shaped mirror 10 and the rotating shaft 20 will be described later.

[0023] The frame portion 60 supports the V-shaped mirror 10 so as to be rotatable back and forth together with the drive unit 4. The frame portion 60 supports the V-shaped mirror 10 at a position where it is sandwiched between a pair of opposing wall-like portions, a base portion 61 and a shaft holder 62.

[0024] The base portion 61 is flat, and a shaft holder 62 is disposed on one surface (e.g., the front surface) in the axial direction (thickness direction) so as to rise from the base portion 61. The unit body 40 of the drive unit 4 is attached to the other surface (rear surface) of the base portion 61. The base portion 61 and the unit body 40 of the drive unit 4 are fixed together by fastening them in parallel to the axial direction via a fastening member 86a and a fastened member 86b, for example.

[0025] The shaft holder 62 holds the V-shaped mirror 10 of the rotating shaft 20 together with the base portion 61 . The holder 62 has a rising wall portion 624 arranged to rise from the base portion 61 along the axial direction, and an opposing wall portion 626 connected to the tip of the rising wall portion 624 in a bent manner and arranged to face the base portion 61.

[0026] The base portion 61 and the opposing wall portion 626 are arranged opposite each other via the rising wall portion 624, and hold the V-shaped mirror 10 in a position sandwiched between them via the rotating shaft 20 that passes through the opening 612 of the base portion 61, and the cross section is formed to be approximately C-shaped (U-shaped).

[0027] In this way, the frame 60 supports the V-shaped mirror 10, which is disposed between the base 61 and the opposing wall 626, from both sides via the rotation shaft 20. This allows the V-shaped mirror 10 to be supported more firmly than in a configuration in which the V-shaped mirror 10 is supported by the rotation shaft 20 that is cantilevered by the drive unit 4, improving impact resistance and vibration resistance.

[0028] The base portion 61 is formed with a connection hole 614 into which a part of the coil body (coil and bobbin) is inserted in the axial direction. The coil body holders 563, 573 are inserted into the connection hole 614, and the coil ends 52a, 54a arranged on the insertion protrusions are connected to a substrate 67. The substrate 67 is a power supply substrate for supplying power to drive the actuator, and is connected to the coils 52, 54 to supply power. The holders 563, 573 hold terminals 58, and the coil ends 52a, 54a are hooked to the terminals 58, and the coil ends 52a, 54a are dipped (soldered) to the terminals 58.

[0029] The base portion 61 and the opposing wall portion 626 are disposed to face each other with a space therebetween in the axial direction. The base portion 61 and the opposing wall portion 626 rotatably support the rotating shaft 20 passing through each of them via bearings 64 and 65, respectively.

[0030] More specifically, the bearing 64 is provided by being fitted into a bearing housing 66, and the bearing housing 66 is fitted into an opening 612 of the base portion 61 (the base portion 61 functions as a shaft support).

[0031] The bearing 65 is fitted into an insertion hole 627 of an opposing wall portion 626 disposed opposite the opening 612, and has a flange that engages with the surface of the wall portion so as to restrict movement of the rotating shaft 20 towards the one end 21 side.

[0032] On the other hand, the bearing 64 has a flange that restricts movement of the bearing 64 toward the other end 23 side relative to the bearing housing 66, and is fitted into the bearing housing 66. Also, the bearing housing 66 is fixed to the base portion 61 by caulking or the like, and restricts movement of the bearing 64 toward the other end 23 side.

[0033] This makes it possible to easily visually check the attachment state of the bearings 64, 65 to the base portion 61 and the opposing wall portion 626 from the axial direction when attaching the bearings 64, 65 to the frame portion 60 during assembly of the rotary reciprocating drive actuator 1.

[0034] The bearings 64, 65 may be formed of rolling bearings (for example, ball bearings) or sliding bearings for the base portion 61. For example, if the bearings 64, 65 are rolling bearings, the coefficient of friction is low and the rotating shaft 20 can be rotated smoothly, thereby improving the driving performance of the rotary reciprocating drive actuator 1.

[0035] As a result, the rotating shaft 20 is rotatably attached to the frame portion 60 via bearings 64, 65, and the V-shaped mirror 10, which is a movable object, is positioned between a pair of opposing base portions 61 and opposing wall portions 626 so that it can rotate back and forth.

[0036] The rotating shaft 20 is mounted on a base portion 61 and a shaft holder 62 via bearings 64 and 65. The V-shaped mirror 10 is supported between the base portion 61 and the shaft holder 62 via the rotating shaft 20 so as to be rotatable back and forth around the axis of the rotating shaft 20.

[0037] In the rotating shaft 20 , a magnet 30 is disposed at one end 21 that protrudes outward from the base portion 61 via a bearing 64 .

[0038] A cylindrical spacer 28 is fitted onto the rotating shaft 20 at a location between the mirror holding portion 16 of the V-shaped mirror 10 and the opposing wall portion 626 through which the other end 23 of the rotating shaft 20 is inserted.

[0039] The movement of the rotating shaft 20 toward one end 21 of the V-shaped mirror 10 is restricted by a stopper 27, and the movement toward the other end 23 is restricted by the biasing force of a preload spring 26, which biases the magnet 30 toward the one end 21 via a bearing 64.

[0040] The stopper 27 is also called a stop ring, and is attached to the other end 23 of the rotating shaft 20 that passes through the opposing wall portion 626 by fitting it into a portion on the outer surface side of the opposing wall portion 626 so as to protrude in the radial direction.

[0041] The spacer 28, together with the stopper 27, restricts the axial movement of the movable body 2 including the V-shaped mirror 10, the rotating shaft 20, and the magnet 30 to a predetermined range including tolerances, and prevents the magnet 30 from coming off the base part 61. The magnet 30 itself is restricted in its movement toward the other end 23 by a bearing 64.

[0042] The preload spring 26 is fitted onto a portion of the rotating shaft 20 that protrudes outward (toward one end 21) of the frame portion 60 (base portion 61). The preload spring 26 is disposed between the base portion 61 (specifically, the bearing 64) and the magnet 30.

[0043] The preload spring 26 expands and contracts in the axial direction to bias the bearing 64 in the axial direction via the magnet 30. The preload spring 26 applies a constant preload to the bearing 64. By applying a constant preload to the bearing 64, the preload spring 26 absorbs the expansion and contraction of the rotating shaft 20 due to fluctuations in load and the temperature difference between the rotating shaft 20 and the base part 61 during rotation. This reduces fluctuations in the amount of preload on the bearing 64, and a stable amount of preload can be obtained. Therefore, the preload spring 26 prevents high-speed rotation of the rotating shaft 20 and axial vibration of the rotating shaft 20, and allows the rotating shaft 20 to be rotated at a high speed and prevents axial vibration compared to a fixed position preload.

[0044] The preload spring 26 may be a compression spring having a predetermined length corresponding to the space in which it is to be placed and having flat surfaces formed on both ends spaced apart in the predetermined length direction, or more preferably, a conical spring that can accommodate large deflection. By using a conical spring, it is possible to obtain an effective biasing force even when the spring is placed in a limited area.

[0045] In this way, the preload spring 26 is disposed between the bearing (particularly, the ball bearing) 64 and the magnet 30, and by applying a preload to the bearing 64, low sliding properties and high reliability of the rotational drive of the rotating shaft 20 can be maintained, and stable drive can be performed. In other words, the preload spring 26 applies a biasing force to the magnet 30 in advance so as to move the magnet 30 in a direction away from the bearing 64, and restricts the movement of the magnet 30 towards the base part 61 or the bearing 64.

[0046] The magnet 30 is disposed at one end 21 of the rotating shaft 20 at a portion that protrudes outward from the base portion 61. The magnet 30 is disposed, for example, in the drive unit 4 described below. The magnet 30 is driven to rotate back and forth by magnetic flux generated by the drive unit 4. That is, the rotating shaft 20 is driven together with the magnet 30, which rotates back and forth due to the mutual electromagnetic action between the drive unit 4 and the magnet 30, and causes the V-shaped mirror 10 to rotate back and forth.

[0047] Furthermore, since the preload spring 26 is disposed inside the rotary reciprocating drive actuator 1, it is not affected by the outside of the rotary reciprocating drive actuator 1, and a stable preload design can be ensured.

[0048] In addition, the preload spring 26 may be a cylindrical coil spring made by winding a round steel wire in a spiral shape, or a wave spring made by winding a plate-shaped steel wire in a spiral or annular shape to add waves as a spring with a low extension / contraction direction, i.e., a low spring height.

[0049] <Unit body 40> The unit body 40 shown in Figs. 2 to 5 surrounds the magnet 30 of the movable body 2 in a direction perpendicular to the axial direction and constitutes a part of the fixed body.

[0050] The unit body 40 is provided on one axial side of the frame portion 60, that is, on the outer surface (back surface) of the base portion 61, and is driven by energizing the coils 52, 54 and by cooperation with the magnet 30 to move the movable body 2.

[0051] The unit body 40 is formed in a rectangular columnar or plate shape, with one axial surface, or front surface, covered by a base portion 61, and the other axial surface, or back surface, covered by a bottom cover 84. The unit body 40 has a coil body 50 having coils 52, 54 and bobbins 56, 57 around which the coils 52, 54 are wound, a core assembly 41, and a neutral position retaining portion 48.

[0052] In this embodiment, the unit body 40, specifically the core assembly 41, is formed in a rectangular frame-type block shape (specifically, a rectangular parallelepiped shape) with the magnetic poles 420a, 420b disposed on the inside.

[0053] The unit body 40 is formed so as to surround the magnetic poles 420a, 420b arranged inside the outer periphery at the frame-shaped outer periphery of the core assembly 41. The unit body 40 is arranged inside the outer periphery along the rectangle, for example, within the back surface of the base part 61, which is a rectangular area seen from the axial direction relative to the base part 61, and has one magnetic path with the magnet 30 arranged on the magnetic path.

[0054] <Core assembly 41> The core assembly 41 constitutes a magnetic circuit having a magnetic path arranged to surround the magnet 30 and the coils 52, 54 from all four sides in a direction perpendicular to the axial direction. The core assembly 41 has adjacent sides of approximately the same length, and has a square magnetic path. The magnetic path of the core assembly 41 has a shape that surrounds the portion where the coils 52, 54 are extrapolated, the magnet 30, and the magnetic poles 420a, 420b from all four sides in the radial direction of the magnet 30.

[0055] The core assembly 41 includes a first core 42 having a plurality of magnetic poles 420a, 420b integrally therewith, a second core 44 arranged adjacent to the first core and surrounding the plurality of magnetic poles 420a, 420b with the first core 42, and a frame-shaped third core 46 connecting the first core 42 and the second core 44. Core assembly 41 is formed by magnetically coupling first to third cores together.

[0056] The first core 42 to the third core 46 form a single magnetic path in which the magnet 30 is sandwiched between the magnetic poles 420a, 420b, and allow the magnetic flux generated when the coils 52, 54 are energized to pass through the multiple magnetic poles 420a, 420b.

[0057] The first core 42 to the third core 46 are each a laminated core formed by laminating electromagnetic steel sheets (lamination members) such as silicon steel sheets. By making the core assembly 41 have a laminated structure, the first core 42 to the third core 46 can be formed at low cost and with complex shapes.

[0058] <First Core 42> The first core 42 has a plurality of rod-shaped bodies 421 (421a, 421b) arranged in parallel, each having opposing magnetic poles 420a, 420b, a connection side portion 422 and side portions 423a, 423b arranged to surround the rod-shaped bodies 421 on three sides, and an inter-pole portion 424.

[0059] In the first core 42, magnetic poles 420a, 420b are arranged at the tip ends of multiple rod-shaped bodies 421a, 421b. A connection side portion 422 extending perpendicular to the extension direction of the rod-shaped bodies 421a, 421b is connected to the base ends of the rod-shaped bodies 421a, 421b, and both side portions 423a, 423b are protruded parallel to the rod-shaped bodies 421a, 421b from both ends of this connection side portion 422. The connection side portion 422, together with the side portions 423a, 423b on both sides of the connection side portion 422, is arranged in a C-shape surrounding the multiple rod-shaped bodies 421a, 421b from three sides.

[0060] A more specific description will be given of the first core 42. The rod-shaped body 421 (421a, 421b), the connection side portion 422, the side portion 423 (423a, 423b) and the inter-pole portion 424 have an integral structure, and the first core 42 is formed in a so-called comb-tooth shape.

[0061] The magnetic poles 420a, 420b are formed at the tip portions of the rod-shaped bodies 421a, 421b, respectively, in a direction perpendicular to the extending direction of the rod-shaped bodies 421a, 421b, so as to face each other with the magnet 30 interposed therebetween. The magnetic poles 420a, 420b face the magnet 30 in the radial direction of the rotating shaft 20, and are disposed spaced apart from each other in the circumferential direction of the rotating shaft 20.

[0062] The bobbins 56 and 57 of the coil bodies are inserted in the areas adjacent to the magnetic poles 420a and 420b, i.e., in the central areas of the rod-shaped bodies 421a and 421b. When the coils 52 and 54 are excited by passing a current through them, the magnetic poles 420a and 420b at the tips of the rod-shaped bodies 421a and 421b generate polarities according to the direction of current passing through the coils 52 and 54.

[0063] The magnetic poles 420a, 420b each have a shape corresponding to the outer peripheral surface of the magnet 30, for example, a shape curved along the outer peripheral surface of the magnet. These curved shapes are arranged, for example, so as to sandwich the magnet 30 in a direction perpendicular to the extension direction of the rod-shaped bodies 421a, 421b and face each other.

[0064] The rod-shaped bodies 421a and 421b have outer dimensions that provide an outer periphery around which the bobbins 56 and 57 can be fitted from the tip side of the rod-shaped bodies 421a and 421b. The bobbins 56 and 57 can be fitted from the tip side of the extension direction of the rod-shaped bodies 421a and 421b, that is, from the tip of the magnetic poles 420a and 420b, and positioned at a predetermined position.

[0065] The connection side portion 422 constitutes one side of the rectangular core assembly 41. The connection side portion 422 connects the base ends of the rod-shaped bodies 421a, 421b, and is disposed so as to extend in a direction perpendicular to the parallel direction of the rod-shaped bodies 421a, 421b.

[0066] The connecting side portion 422 mainly connects the base end portions of the rod-shaped bodies 421a, 421b to the both side portions 423a, 423b. It is preferable that the both side portions 423a, 423b are in close contact with both ends of the second core 44, but here, they are arranged so that there is a gap between each of the both side portions 423a, 423b and both ends of the second core 44.

[0067] The connecting side portion 422 and both side portions 423a, 423b, together with the second core 44, are provided so as to be stacked on the third core 46 in a state of being in close contact with the third core 46 in the axial direction.

[0068] The connecting side portion 422 enables the multiple magnetic poles 420a, 420b to be positioned precisely so that they do not shift when the core assembly 41, and therefore the drive unit 4, are assembled.

[0069] On the other hand, the inter-pole portion 424 uses the magnetic attraction force generated between the tip inter-pole 424a and the opposing magnet 30 to position the magnet 30 at a neutral position equidistant from both of the multiple magnetic poles 420a, 420b, and at a position that serves as a rotational reference for the reciprocating rotation.

[0070] The interpole portion 424 is provided on the connecting side portion 422 between the rod-shaped bodies 421a, 421b and extends parallel to the rod-shaped bodies 421a, 421b, and faces the outer periphery of the magnet 30 in the radial direction at its tip.

[0071] The inter-pole portion 424 is disposed opposite the neutral position holder 48, and when the neutral position holder 48 attracts the first pole of the magnet 30, it attracts the second pole, which is another pole of the magnet 30, thereby reinforcing the attraction state of the neutral position holder 48. The neutral position holder 48 attracts the magnet 30 with a magnetic pole generated between it and the magnet 30, and holds the magnet 30 in a neutral position where the distances between the magnetic poles 420a, 420b are equal when the magnet 30 rotates back and forth. The neutral position holder 48 will be described in detail later.

[0072] The inter-pole portion 424 is made of a magnetic material and generates a magnetic attraction force between itself and the neutral position holder magnet 30 (more specifically, the pole 32b), and moves the pole 32b of the magnet 30, which is different from the pole 32a that is attracted to the neutral position holder 48, to an opposing position (directly in front). Through this action, the inter-pole portion 424 offsets the axial radial load acting on the movable body 2 due to the magnetic attraction force in the neutral position holder 48. Note that "offsetting the axial radial load" also includes "making it possible to offset the axial radial load".

[0073] The inter-pole (inter-pole surface) at the tip of inter-pole section 424 that faces the outer circumferential surface of magnet 30 is a curved surface that corresponds to the shape of the outer circumferential surface of magnet 30, and has a uniform gap over the entire surface between it and the outer circumferential surface of magnet 30. Inter-pole section 424, together with neutral position holder 48, is disposed so as to surround magnet 30 within core assembly 41, resulting in a layout that occupies the minimum space, enabling a more compact rotary reciprocating drive actuator 1 to be realized.

[0074] <Coil body (coil and bobbin)> 2 to 5, the coils 52, 54 are wound around cylindrical bobbins 56, 57 to form a coil body. The coil body, together with the magnet 30, forms an electromagnetic drive portion that rotates the movable body 2 back and forth.

[0075] The bobbins 56, 57 have flanges 561, 571 at both ends of a cylindrical body around which the coils 52, 54 are disposed. One side of the flanges of each of the bobbins 56, 57 is provided with holding portions 563, 573, part of which protrudes in a direction perpendicular to the axes of the coils 52, 54. The holding portions 563, 573 hold terminals (pin terminals) 58 to which the windings of the coils 52, 54 are connected.

[0076] The holding portions 563 and 573 hold one end of an L-shaped terminal 58 connected to the end of the winding of the coils 52 and 54 so that the other end is exposed to the outside. The coil bodies are respectively inserted around the rod-shaped bodies 421a and 421b of the first core 42 and are disposed adjacent to the magnetic poles 420a and 420b of the first core 42.

[0077] The winding direction of the coils 52, 54 is set so that magnetic flux is suitably generated from one of the multiple magnetic poles of the first core 42 to the other when a current is applied.

[0078] The coil body is arranged in the core assembly 41 with the holding portions 563, 573 protruding upward, and when the core assembly 41 is fixed to the base portion 61, the holding portions 563, 573 are inserted into the connection holes 614 of the base portion 61 to connect the terminals 58 to the substrate 67. That is, the coils 52, 54 are connected to the substrate 67 so that, when current is applied to the coils 52, 54, a magnetic flux is suitably generated from one of the multiple magnetic poles 420a, 420b of the first core 42 to the other.

[0079] <Second Core 44> The second core 44 is formed in a columnar shape with a C-shaped cross section, and forms a magnetic path through which magnetic flux passes to the magnetic poles 420a, 420b when a current is applied to the coils 52, 54.

[0080] The second core 44 has the same thickness (length in the axial direction) as both side portions 423a, 423b, and is disposed so as to be connected to or adjacent to the tip surfaces of both side portions 423a, 423b.

[0081] The second core 44 is fixed to the base portion 61 and the bottom cover 84 in a state of being in close contact with the third core 46 via fastening members 86a inserted into mounting holes (fastening holes) 402 similar to mounting holes (fastening holes) 402 provided at both ends of the connection side portion 422 of the first core 42. The mounting holes 402 have the same diameter as the through hole of the bottom cover 84, and are formed so as to extend parallel to the rotation shaft 20. A neutral position retaining portion 48 is attached to the second core 44 at a central portion in the extension direction and at a portion facing the magnet 30 .

[0082] <Third Core 46> The third core 46 is formed into a rectangular frame plate shape and is attached in face-to-face contact with the rectangular frame-shaped portion formed by both the first core 42 and the second core 44, i.e., the connection side portion 422 and both side portions 423 of the first core 42, and the second core 44.

[0083] The third core 46 has a predetermined thickness surrounding the multiple magnetic poles 420a, 420b by connecting the first core 42 and the second core 44, and forms a square frame-shaped magnetic path connecting the multiple magnetic poles 420a, 420b. The core assembly is fixed to the base portion 61 via the third core 46.

[0084] Specifically, the third core 46 faces the connection side portion 422 and both side portions 423a, 423b of the first core 42 in the extension direction of the rotation shaft 20 and is in surface contact with each other.

[0085] As a result, the third core 46 is disposed around the rotating shaft 20 so as to surround the magnetic poles of the rod-shaped bodies 421 a and 421 b and the coils 52 and 54 , and forms a seamless magnetic path around the rotating shaft 20 .

[0086] The first to third cores 42-43 include an enclosing portion that encloses the coils 52, 54, and can form a flow of magnetic flux that passes from one of the magnetic poles 420a, 420b through the first core 42, the third core 46, the second core 44, the third core 46, and the other magnetic pole of the first core 42 in this order. The enclosing portion includes, for example, both side portions 423a, 423b, the connecting side portion 422, and the entire third core 46. In addition, the frame-shaped enclosing portion of the first to third cores 42-43 encloses the magnetic poles 420a, 420b and the magnet 30 between the magnetic poles 420a, 420b, and therefore it is possible to prevent an external member from coming into contact with the coils 52, 54 from the outside.

[0087] When the drive unit 4 is assembled, the rotating shaft 20 is inserted into the space surrounded by the magnetic poles. The magnet 30 attached to the rotating shaft 20 is located in this space, and the magnetic poles face the magnet 30 at a precise position with an air gap G between them.

[0088] <Magnet 30> The magnet 30 is a ring-shaped magnet in which the S poles 32a and the N poles 32b are alternately arranged in the circumferential direction. The magnet 30 is attached to the circumferential surface of the rotating shaft 20 so as to be located in a space surrounded by the magnetic poles 420a, 420b of the core assembly 41, the neutral position holder 48, and the interpole when the rotary reciprocating actuator 1 is assembled. The magnet 30 is fixed so as to surround the outer periphery of the rotating shaft 20. When the coils 52 and 54 are energized, the first core 42, the second core 44, and the third core 46 including the rod-shaped bodies 421a and 421b are excited, and the magnetic poles 420a and 420b are generated with a polarity according to the energizing direction. As a result, a magnetic force (attraction force and repulsion force) is generated between the magnetic poles 420a and 420b and the magnet 30.

[0089] In this embodiment, magnet 30 is a two-pole magnet magnetized so as to be equally divided into S pole 32a and N pole 32b. As long as the number of magnetic poles of magnet 30 (two in this embodiment) is equal to the number of magnetic poles 420a, 420b of core assembly 41, magnet 30 may have two or more poles depending on the amplitude of the movable body when it is moved.

[0090] The polarity of the magnet 30 is switched at a boundary portion (magnetic pole switching portion) 32c between different magnetic poles (S pole 32a and N pole 32b) in the circumferential direction. When the magnet 30 is held at a position of an initial angle corresponding to the initial position (neutral position, also called the initial position of the movable body 20), the magnetic pole switching portion 32c faces each of the magnetic poles 420a, 420b, so that the drive unit 4 can generate a maximum torque when driven and stably drive the movable body 2.

[0091] By configuring the magnet 30 as a two-pole magnet, the movable object can be easily driven with high amplitude in cooperation with the core assembly 41, and the driving performance can be improved. That is, the V-shaped mirror 10 can achieve amplitude at a wider angle than a configuration in which a single-sided mirror of the same width is used. In the embodiment, the magnet 30 has a pair of magnetic pole switching parts 32c, but it may have two or more pairs of magnetic pole switching parts.

[0092] <Neutral position holding unit (magnet initial angle position holding unit) 48> 2 to 5 is incorporated into the core assembly 41 so as to face the magnet 30 via an air gap G. The neutral position holder 48 is attached to the second core 44, for example, in a position where its magnetic pole faces the magnet 30. The neutral position holder 48 is a magnetic body, and is disposed between the multiple magnetic poles 420a, 420b in the circumferential direction, facing the magnet 30 in the radial direction of the rotating shaft 20. The neutral position holder 48 attracts the magnet 30, and biases the magnet 30 (the movable body 2) toward the initial position (initial angular position) of the reciprocating rotation.

[0093] The neutral position holder 48 is a magnetic body, for example a permanent magnet, and is disposed with its magnetic poles facing the magnet 30, and attracts the magnet 30 by the magnetic attraction force generated between the neutral position holder 48 and the magnet 30.

[0094] Neutral position retaining portion 48, together with rod-shaped bodies 421a, 421b, functions as a magnetic spring forming portion that forms a magnetic spring between magnet 30 and itself. Due to this magnetic spring, in a normal state (when not energized) in which no current is passed through coils 52, 54, the rotational angle position of magnet 30, i.e., the rotational angle position of rotating shaft 20, is held in a neutral position.

[0095] At this time, the pole 32b (N pole shown in FIG. 3) opposite the pole 32a (S pole in FIG. 3) of the magnet 30 that attracts the neutral position holding portion 48 attracts the commutating pole portion 424. As described above, the neutral position holding portion 48 and the commutating pole portion 424 effectively hold the magnet 30, that is, the V-shaped mirror 10 that is the movable object, in the neutral position.

[0096] As described above, the neutral position is a position where the magnet 30 is located at an initial angle that is a reference for the reciprocating motion when the magnet 30 rotates back and forth around the axis. The neutral position is also a neutral position where the magnet rotates left and right at the same distance during reciprocating rotation (oscillation), and is a position where the angles of left and right rotation around the axis during reciprocating rotation are the same. When the magnet 30 is held in the neutral position, the magnetic pole switching portion (boundary portion) 32c of the magnet 30 faces the magnetic poles of the rod-shaped bodies 421a and 421b.

[0097] The mounting posture of the V-shaped mirror 10 is adjusted based on the state in which the magnet 30 is in the neutral position. The neutral position holder 48 may be composed of a magnetic body (non-magnetized magnetic body) that generates a magnetic attraction force between itself and the magnet 30, instead of a permanent magnet (magnetized magnetic body).

[0098] <Positioning cover 82 and bottom cover 84> As shown in FIGS. 2, 4 and 5, one axial surface (upper surface) of core assembly 41 is covered by base portion 61, and the other axial surface (lower surface) is covered by positioning cover 82 and bottom cover 84.

[0099] The positioning cover 82 is formed in a frame shape and is attached so as to determine the position between the magnet 30 and the core assembly 41. It is possible to maintain the distance from the core assembly 41 to the bottom cover 84 and to maintain clearance such as the movable range to provide a suitable drive circuit. The positioning cover 82 is attached so as to overlap the outer surface of the core assembly 41 .

[0100] The positioning cover 82 is provided with a cutout 822 that serves as an escape portion for the magnet 30, and holes such as a through hole, a positioning hole, and a position adjustment hole for fixing to the base portion 61. These holes are formed parallel to the axial direction of the rotating shaft 20. By inserting the fastening member into the through hole, attachment to the base portion 61 or assembly of the drive unit 4, and ultimately assembly of the rotary reciprocating drive actuator 1, can be performed in one axial direction.

[0101] The bottom cover 84 prevents contamination from entering the core assembly from one end (one end surface) of the rotary reciprocating drive actuator 1. The bottom cover 84 is preferably made of a non-magnetic, electrically conductive material with high electrical conductivity, and functions as an electromagnetic shield. In other words, the bottom cover 84 can suppress the incidence of noise into the core assembly 41 and the emission of noise from the core assembly 41 to the outside.

[0102] The bottom cover 84 may be made of a material that is non-magnetic, electrically conductive, and has high thermal conductivity, such as an aluminum alloy, etc. Aluminum alloys offer a high degree of freedom in design and can easily be given the desired rigidity.

[0103] The outer surface (upper surface) of the facing wall portion 626 is formed in a concave shape and functions as a sensor receiving portion 626a. The other end 23 of the rotating shaft 20 protrudes into the facing wall portion 626 and is disposed in the concave sensor receiving portion 626a.

[0104] <Angle detection unit 7> An angle detection unit 7 is disposed on the front (top) side of the opposing wall 626. The angle detection unit 7 detects the rotation angle of the movable body 2 including the magnet 30 and the rotation shaft 20. The rotary reciprocating drive actuator 1 can control the rotation angle position and rotation speed of the movable body during driving, specifically, the V-shaped mirror 10 which is the movable object, via a control unit (not shown) based on the detection result of the angle detection unit 7. The control unit may be mounted on the substrate 67.

[0105] The angle detection unit 7 may use a sensor of either a magnetic type or an optical type. In this embodiment, the angle detection unit 7 has a sensor board 72, an encoder disk 74 housed in the sensor housing portion 626a, an encoder hub 76, and an optical sensor (sensor) 78 having a light source, a light receiving element, and the like.

[0106] The angle detection unit 7 detects the rotation of the encoder disk 74, thereby detecting the rotation angle of the rotating shaft 20 and, ultimately, the V-shaped mirror 10. The encoder disk 74 is fixed to the other end 23 of the rotating shaft 20 in the sensor housing 626a via an encoder hub 76, and rotates integrally with the magnet 30 and the V-shaped mirror 10 around the rotating shaft 20. The rotational position of the encoder disk 74 is the same as the rotational position of the rotating shaft 20.

[0107] The optical sensor 78 is mounted on the sensor board 72, emits light parallel to the axial direction to the encoder disk 74, and detects the rotational position (angle) of the encoder disk 74 based on the reflected light. This makes it possible to detect the rotational positions of the magnet 30 and the V-shaped mirror 10. The optical sensor 78 is mounted on the back surface of the sensor substrate 72 and is therefore accommodated within the sensor accommodating portion 626a by the sensor substrate 72.

[0108] The optical sensor 78 is mounted on a sensor board 72 that is disposed perpendicular to the other end 23 of the rotating shaft 20, and therefore can be easily positioned opposite the encoder disk 74 in the direction of the rotating shaft.

[0109] The sensor board 72 is attached to the upper surface of the opposing wall portion 626 so as to close the sensor receiving portion 626a, thereby closing the sensor receiving portion 626a.

[0110] The sensor board 72 is a board on which an optical sensor 78 is mounted, which detects the rotation angle of the rotating shaft 20. The sensor board 72 is disposed so as to cover the core assembly 41, with the optical sensor 78 positioned to face the magnet 30 side in the axial direction.

[0111] The sensor substrate 72 is fixed to the opposing wall portion 626 via the fixing member 77, preventing the intrusion of unwanted substances from the outside, such as foreign matter, into the sensing portion of the angle detection unit 7. That is, contamination of the sensor housing portion 626a can be prevented.

[0112] In this way, the sensor substrate 72 and the opposing wall portion 626 are detachably fixed by the fixing member 77 while being positioned by the positioning pin 79 through holes formed in the same shape and penetrating in the axial direction.

[0113] In addition to the circuit for detecting the rotational position (angle) of the encoder disk, the sensor substrate 72 may be mounted with a circuit for supplying power to the coils 52 and 54. In this case, the power supply circuit is not mounted on the substrate 67.

[0114] <Position relationship between the V-shaped mirror and the rotation axis> FIG. 6 is a horizontal cross-sectional view showing the positional relationship between the mirror holding portion and the rotation axis.

[0115] As shown in FIGS. 2, 4, and 6, the V-shaped mirror 10 is configured by holding the first mirror 12 and the second mirror 14 with the mirror holding portion 16, and is fixed to the rotation axis 20 such that its center of gravity position CG coincides with (is close to) the center (axis) J of the rotation axis 20.

[0116] The first mirror 12 and the second mirror 14 are each formed in a rectangular plate shape, for example, and are held by the mirror holding portion 16 on the back surface with their surfaces being the reflection surfaces 12a and 14a, respectively. The first mirror 12 and the second mirror 14 are configured such that the distances from the rotation axis 20 to the reflection surfaces 12a and 14a are the same.

[0117] The first mirror 12 and the second mirror 14 are arranged symmetrically about a ridge line parallel to the axis of the rotation axis 20.

[0118] When the V-shaped mirror 10 is viewed from the axial direction, the rotation axis 20 is disposed inside a triangular area formed by the first mirror 12, the second mirror 14, and an imaginary line T connecting the ends of the first mirror 12 and the second mirror 14. In other words, the axis J of the rotation axis 20 is located within a triangular area sandwiched between the imaginary lines T connecting the spaced-apart ends of the mirror parts (the first mirror 12, the second mirror 14) arranged in a V shape.

[0119] The angle at which the first mirror 12 and the second mirror 14 open at a predetermined angle and form a V shape between the first mirror 12 and the second mirror 14 centered on the ridge line is preferably a right angle, but may be an angle less than 90 degrees, i.e., an acute angle.

[0120] The mirror holding portion 16 has a rotating shaft 20 attached thereto, and includes a rotating shaft holding portion 162 having an outer surface capable of holding the first mirror 12 and the second mirror 14 in a V-shape, and holding frames 164, 166 extending in a V-shape from the outer surface of the rotating shaft holding portion.

[0121] The holding frames 164, 166 are, for example, planar, have a length extending along the width direction (direction extending in a V-shape) of the first mirror 12 and the second mirror 14, and are joined to and hold the back surfaces of the first mirror 12 and the second mirror 14. The holding frames 164, 166 are longer than half the width direction of the first mirror 12 and the second mirror 14 on the back surfaces of the first mirror 12 and the second mirror 14, respectively, and are preferably at least 2 / 3 of the length.

[0122] For example, the holding frames 164, 166 are strips formed in a V-shape, and a rectangular column-shaped rotating shaft holding part 162 into which the rotating shaft 20 is inserted and fitted is integrally provided on the back side of the ridge line, thereby forming the mirror holding part 16. This mirror holding part 16 may be made of metal, and is preferably made of aluminum. The first mirror 12 and the second mirror 14 may be made of glass or the like.

[0123] For example, the rotation axis 20 may be provided within a circle r having a predetermined radius (e.g., a radius of 3 mm) centered on the midpoint of a line connecting the midpoints of the widths w of the two mirrors that are the first mirror 12 and the second mirror 14. In addition, the eccentricity e between the center of gravity and the axis of the rotation axis may be set at a position that satisfies w / 2√2-√2x (where x is the distance between the mirror surface and the center of gravity, and w is the width of the mirror).

[0124] In this way, the mirror holding part 16 and the rotating shaft 20 may be joined so that the center of gravity CG of the V-shaped mirror (including the mirror holding part 16, the first mirror 12 and the second mirror 14) is adjacent to the axis J of the rotating shaft 20, and the rotating shaft 20 may be positioned at a position that includes the center of gravity of the mirror holding part 16. Further, the mirror holding portion 16 is provided so as to be located in a region where the rotation shaft 20 or the rotation center of the rotation shaft 20 is sandwiched between the two mirrors in a direction perpendicular to the axial direction.

[0125] The mirror holder 16 includes the first mirror 12 and the second mirror 14 arranged in a V-shape, V-shaped holder frames 164, 166 that fix and hold the mirrors, and a rotation shaft holder 162. The first mirror 12 and the second mirror 14 have ridges formed by butting adjacent sides together to form a V-shape. The holder frames 164, 166 are disposed on the rear surfaces of the mirrors 12, 14.

[0126] Rotating shaft holding portion 162 is a thick portion on the back surface of the V-shaped butted portion of holding frames 164, 166, and has an axis extending parallel to the one side, and fixes holding frames 164, 166. Rotating shaft holding portion 162 is a thick portion provided on the back surface of a corner of the V-shaped holding frame that holds a mirror arranged in a V shape on its back surface.

[0127] In addition, the mirror holding portion 16 has a V-shaped surface 16a that holds a V-shaped mirror (which may be formed from a single mirror) having the first mirror 12 and the second mirror 14, and the opposite side has a W-shaped back surface 16b, resulting in a shape in which a thick portion is provided between the intermediate bending portions (which may be referred to as the intermediate bending portions of the V-shaped mirror 10) on the front and back surfaces of the mirror holding portion 16. The rotating shaft 20 is held by this thick portion.

[0128] Either configuration of the mirror holding unit 16 can ensure the rigidity of the mirror while achieving low inertia drive.

[0129] As a result, eccentricity during reciprocating rotation is prevented, which would result in an increase in the radial load on the bearing 64 and would not cause unwanted vibrations or increased drive noise. The first mirror 12 and the second mirror 14 may be integrally formed into a V-shape.

[0130] Here, the operation of the rotary reciprocating actuator 1 will be described with reference to Figures 7 and 8. Figure 7 is a diagram showing a magnetic circuit of a rotary reciprocating actuator of one embodiment according to the present invention, and Figure 8 is a diagram provided for explaining the operation of the magnetic circuit of a rotary reciprocating actuator of one embodiment according to the present invention.

[0131] 7, the magnetic poles 420a, 420b of the two rod-shaped bodies 421a, 421b of the core assembly 41 are arranged to sandwich the magnet 30 with an air gap G therebetween. As a result, when the coils 52, 54 are not energized, the magnet 30 is held in the neutral position by the magnetic attraction force between the magnet 30 and the neutral position holding part 48, as shown in FIG.

[0132] In this neutral position, one of the S pole 32a and N pole 32b of the magnet 30 (S pole 32a in FIG. 7) is attracted to the neutral position holding portion 48 (see magnetic spring torque FM in FIG. 8). At this time, the magnetic pole switching portions of the magnet 30 are located at positions facing (directly facing) the centers of the magnetic poles 420a, 420b of the core assembly 41. Also, the interpole portion 424 attracts the other of the S pole 32a and N pole 32b of the magnet 30 (N pole 32b in FIG. 7). This allows the magnet 30 to move to the neutral position more effectively.

[0133] When current is applied to the coils 52 and 54, the core assembly 41 is excited, and the magnetic poles 420a and 420b have a polarity according to the direction of current application. For example, as shown in Fig. 8, when current is applied to the coils 52 and 54, a magnetic flux is generated inside the core assembly 41, and the magnetic pole 420a becomes a north pole and the magnetic pole 420b becomes a south pole.

[0134] As a result, the magnetic pole 420a magnetized to an N pole attracts the S pole 32a of the magnet 30, and the magnetic pole 420b magnetized to an S pole attracts the N pole 32b of the magnet 30. Then, a torque in the F direction is generated around the axis of the rotating shaft 20 in the magnet 30, and the magnet 30 rotates in the F direction. Accordingly, the rotating shaft 20 also rotates in the F direction, and the V-shaped mirror 10 fixed to the rotating shaft 20 also rotates in the F direction.

[0135] Next, when current is applied to the coils 52 and 54 in the opposite direction, the flow of magnetic flux generated inside the core assembly 41 becomes the opposite direction to that shown in Fig. 8, and the magnetic pole 420a becomes an S pole, and the magnetic pole 420b becomes an N pole. The magnetic pole 420a magnetized to an S pole attracts the N pole 32b of the magnet 30, and the magnetic pole 420b magnetized to an N pole attracts the S pole 32a of the magnet 30. Then, a torque in the opposite direction to the F direction is generated in the magnet 30 around the axis of the rotating shaft 20, and the magnet 30 rotates in the opposite direction to the F direction. Accordingly, the rotating shaft 20 also rotates, and the V-shaped mirror 10 fixed to the rotating shaft 20 also rotates in the opposite direction to the direction shown in Fig. 8. The rotary reciprocating actuator 1 rotates and reciprocates the V-shaped mirror 10 by repeating the above operations.

[0136] In practice, the rotary reciprocating actuator 1 is driven by AC waves input to the coils 52, 54 from a power supply unit (equivalent to, for example, the drive signal supply unit 103 in FIG. 32). That is, the current flow direction of the coils 52, 54 switches periodically. When the current flow direction switches, the magnet 30 is urged to return to the neutral position by the magnetic attraction force between the neutral position holder 48 and the magnet 30, that is, the restoring force of the magnetic spring (the magnetic spring torque FM shown in FIG. 8 and a torque in the opposite direction). As a result, a torque in the F direction and a torque in the opposite direction to the F direction act alternately on the movable body 2 around the axis. As a result, the movable body 2 is rotary and reciprocatingly driven.

[0137] The following is a brief explanation of the driving principle of the rotary reciprocating actuator 1. In the rotary reciprocating actuator 1 of this embodiment, the moment of inertia of the movable body (movable body 2) is J [kg m 2 ], the spring constant in the torsional direction of the magnetic spring (magnetic poles 420a, 420b, neutral position holder 48, and magnet 30) is K sp [N m / rad], the movable body has a resonant frequency F r It vibrates (reciprocating rotation) at [Hz].

[0138]

number

[0139] Since the movable body constitutes a mass part in the vibration model of the spring-mass system, the resonance frequency F r When an AC wave having a frequency equal to the resonant frequency F of the movable body is input to the coils 52 and 54 from the power supply unit, the movable body is in a resonant state. r By inputting an AC wave having a frequency substantially equal to that of the movable body, the movable body can be vibrated efficiently.

[0140] Below are equations of motion and circuit equations showing the driving principle of the rotary reciprocating actuator 1. The rotary reciprocating actuator 1 is driven based on the equation of motion shown in equation (2) and the circuit equation shown in equation (3).

[0141]

number

[0142]

number

[0143] That is, the moment of inertia of the movable body in the rotary reciprocating actuator 1, J [kg m 2 ], rotation angle θ(t) [rad], torque constant K t [N·m / A], current i(t) [A], spring constant K sp [N m / rad], damping coefficient D [N m / (rad / s)], load torque T Loss [N m], etc. can be changed as appropriate within the range that satisfies formula (2). In addition, the voltage e(t) [V], resistance R [Ω], inductance L [H], and back electromotive force constant K e [V / (rad / s)] can be changed as appropriate within the range that satisfies formula (3).

[0144] In this way, the rotary reciprocating actuator 1 has a moment of inertia J of the movable body and a spring constant K of the magnetic spring. sp The resonant frequency F is determined by r When the coil is energized with an AC wave corresponding to the above, it is possible to obtain a large vibration output efficiently.

[0145] <Assembly structure> FIG. 9 is a diagram for explaining the assembly structure of the rotary reciprocating actuator to the housing. When the rotary reciprocating actuator 1 is attached to the body of a product, the rotary reciprocating actuator 1 is fixed to a fixed base portion 800 provided on the body side (for example, as a part of the body).

[0146] When fixing the rotary reciprocating actuator 1 to the product housing, if the axis of rotation is used as a reference, it is desirable to fix it at a position where the dimensions can be specified from that reference, that is, at a position that is set based on the position of the movable part after the positioning of the movable part is determined, because this allows for highly accurate fixing. Also, it is necessary to fix it while taking into account the effects of disturbances, etc., and it is desirable to fix it at a position close to the center of gravity, for example.

[0147] The fixed base 800 is configured as a U-shaped portion having fixed walls 804, 806 standing opposite to each other with a space therebetween. The rotary reciprocating actuator 1 is fixed to the fixed base 800 so that the core assembly 41 of the drive unit 4 is located inside this U-shape. The rotary reciprocating actuator 1 is fixed to the fixed base 800 by the fastening members 87 inserted through the fastening holes 69, with both side portions of the base 61 abutting against the upper end surfaces of the fixed walls 804, 806 with the standing direction of the fixed base 800 and the axial direction parallel to each other. In addition to the fastening holes 807 into which the fastening members 87 are inserted, the upper end surfaces of the fixed walls 804, 806 are provided with positioning holes (one of which is an elongated hole) 809 into which the positioning pin 616 is inserted.

[0148] When attaching the rotary reciprocating actuator 1 to the fixed base 800, a positioning pin 616 parallel to the axis is inserted into a positioning hole 809 parallel to the axis, and the actuator is rotated around the pin. This adjusts the positions of both the rotary reciprocating actuator 1 and the fixed base 800. A rod or the like is inserted into the positioning cutout to further adjust the positions, and the fixing hole 69 and the fastening hole 807 are aligned, and the fastening member 87 is inserted through both to fasten them.

[0149] Since the axial direction of the rotary shaft 20 is the same as the axial direction of the bearings 64, 65 resulting from the position of the V-shaped mirror 10, the rotary reciprocating actuator 1 can be positioned and fixed to the fixed base 800 with high precision.

[0150] The rotary reciprocating actuator 1 can be manufactured by fixing each part from a direction parallel to the axis, or can be fixed to a housing. Also, a fixing hole 69 is provided in the base part 61 between the driving part (core assembly 41) of the drive unit 4 and the V-shaped mirror 10. Also, the base part 61 is provided with holes and the like for fixing each part including the bearing 64, and the wall part 211B is fixed to the fixed base part 800 using these. These can be positioned and fixed to the fixed base part 800 on the same processed surface, allowing for high-precision fixing.

[0151] In this way, the rotary reciprocating actuator 1 can be positioned and fixed in a direction parallel to the rotary shaft 20 relative to the fixed base (housing) 800, so that the additional dimension is smaller and it is possible to perform highly accurate positioning and fixing compared to fixing with other components. Also, since the center of gravity is between the V-shaped mirror 10 and the core assembly 41, it can be held stably.

[0152] FIG. 10 is a block diagram showing the configuration of a main part of a scanner system 100 using the rotary reciprocating actuator 1. As shown in FIG.

[0153] The scanner system 100 includes, in addition to the rotary reciprocating actuator 1, a laser emission unit (light irradiation unit) 101, a laser control unit 102, a drive signal supply unit 103, and a position control signal calculation unit 104.

[0154] The laser emission unit 101 has, for example, an LD (laser diode) serving as a light source, a lens system for converging the laser light output from the light source, etc. The laser control unit 102 controls the laser emission unit 101. The laser light emitted from the laser emission unit 101 is incident on a mirror 121 of the rotary reciprocating actuator 1.

[0155] The position control signal calculation unit 104 generates and outputs a drive signal for controlling the rotation shaft 20 (mirror 121) to be at the target angular position, with reference to the angular position of the rotation shaft 20 (mirror 121) acquired by the angle detection unit 7 and the target angular position. For example, the position control signal calculation unit 104 generates a position control signal based on the acquired angular position of the rotation shaft 20 (mirror 121) and a signal indicating the target angular position converted using sawtooth waveform data or the like stored in a waveform memory (not shown). The position control signal calculation unit 104 outputs the generated position control signal to the drive signal supply unit 103.

[0156] Based on the position control signal, the drive signal supply unit 103 supplies a drive signal to the coils 52, 54 of the rotary reciprocating actuator 1 so that the angular position of the rotary shaft 20 (mirror 121) becomes a desired angular position. This enables the scanner system 100 to emit scanning light from the rotary reciprocating actuator 1 to a predetermined scanning area.

[0157] <Summary> As described above, the rotary reciprocating actuator 1 according to this embodiment has a movable body 2 having a rotating shaft (shaft) 20 to which a mirror section (movable object) is connected, and a magnet 30 fixed to the rotating shaft 20. It reciprocally rotates a V-shaped mirror 10 as a movable object. The magnet 30 is a ring-shaped magnet with S poles 32a and N poles 32b alternately arranged in the circumferential direction on the outer circumferential surface.

[0158] As a result, the magnet 30 rotates on the movable body 2 side, so there is no effect on the mirror (movable part) on the movable body side due to coil heat during movement, and the input current can be increased to achieve high output. In addition, the initial position retention structure using a magnetic spring allows for a high amplitude actuator.

[0159] In the rotary reciprocating actuator 1, the V-shaped mirror 10 is disposed close to the center of gravity of the rotary shaft 20 so that the axis of the rotary shaft 20 is aligned with the center of gravity of the V-shaped mirror. This reduces inertia and increases the input current, allowing the V-shaped mirror 10 to be driven by preferably increasing the resonance, thereby achieving a low-profile, high-output rotary reciprocating actuator.

[0160] In addition, since the mirror has a V-shape, it is possible to provide a low-profile scanner configuration while ensuring a wide reflective surface for optical scanning in response to the demand for a wide angle of view and a low-profile configuration in an optical scanner configuration. Note that the left and right arrangement of the light emitting and receiving parts via the V-shape mirror 10 may be any configuration.

[0161] Furthermore, the sensor board 72 covers elements of the rotation detection unit, such as the detection unit (encoder disk) of the sensor component, axially outward of the unit body 40 (core assembly 41, positioning cover 82, bottom cover 84). This makes it possible for the sensor board 72 to prevent contamination of the sensor housing portion 626a, and in turn, the air gap G between the magnet 30 and the core assembly 41. In this way, it is possible to prevent foreign matter from entering the air gap G, prevent operational malfunctions, and enable optimal operation.

[0162] Furthermore, since the magnet 30 is arranged inside the drive unit 4 of the rotary reciprocating drive actuator, no magnet is arranged on the outside, and the magnetic flux is not distributed to the outside (front side), reducing leakage magnetic flux to the front side, and the actuator can be arranged even if there are magnetically sensitive products in the vicinity.

[0163] Since the core assembly 41 of the drive unit 4 is in the shape of a rectangular frame block, the installation space for the core assembly 41 can be limited, for example, within a rectangular area (area viewed in the axial direction) on the back surface of the base portion 61, ensuring sufficient magnetic path length and enabling high-amplitude drive of the movable body 2.

[0164] Furthermore, when performing maintenance on the angle detection unit 7, the sensor board 72 can be removed by simply removing the fastening member 77 to expose the sensor components to the outside. The sensor components are, for example, rotation angle inspection components such as the light sensor 78, the encoder disk 74, the encoder hub 76, and other light emitting and light receiving parts on the mounting surface of the sensor board 72. In other words, when a malfunction occurs, the sensor components, which are expensive parts, can be immediately exposed to the outside, allowing for easy repair or replacement without having to discard the entire sensor component.

[0165] Furthermore, when the sensor unit is an optical sensor, it is possible to prevent light interference with the sensor housing portion 626a without using a separate light blocking member.

[0166] Moreover, the movable object is the V-shaped mirror 10 (particularly the mirror 121) that reflects the scanning light. This allows the rotary reciprocating actuator 1 to be used as a scanner that performs optical scanning.

[0167] Moreover, since the unit body 40 has a configuration in which the coils 52, 54 are surrounded by the first to third cores, it is possible to suppress electromagnetic noise generated from the coils 52, 54. In addition, leakage magnetic flux from the magnet 30 and the coils 52, 54 can be suppressed.

[0168] Also, for example, in the embodiment, the case where the rotary reciprocating actuator 1 is resonantly driven has been described, but the present invention can also be applied to the case where it is non-resonantly driven.

[0169] The configuration of the drive unit 4 is not limited to that described in the embodiment. For example, the core may have a magnetic pole portion that is excited by energizing the coil to generate a polarity, and when the rotating shaft is attached to the fixed body, the magnetic pole portion and the outer circumferential surface of the magnet may face each other via an air gap. The coil may have a configuration that appropriately generates a magnetic flux from one side of the magnetic pole portion of the core to the other side when energized.

[0170] Furthermore, the neutral position retaining portion 48 provided on the fixed body is configured to be attached to the second core 44, but this is not limiting and the neutral position retaining portion 48 may be configured to be provided on another component of the fixed body. In these cases, the neutral position retaining portion 48 may be accommodated in the second core 44.

[0171] In the V-shaped mirror 10, the first mirror 12 and the second mirror 14 may be an integrated mirror, and at least one of the first mirror 12 and the second mirror 14 and the mirror holder 16 may be formed integrally. Furthermore, the mirror holder 16 and the rotation shaft 20 may be formed integrally, and the mirror portions of the first mirror 12 and the second mirror 14, the mirror holder, and the rotation shaft may all be formed integrally.

[0172] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0173] The present invention is suitable for use in, for example, LiDAR devices and scanner systems. [Explanation of symbols]

[0174] 1 Rotation Reciprocating Actuator 2 Movable body 4 Drive unit 7 Angle detection unit 10 V-shaped mirror 12 Mirror No. 1 14 2nd Mirror 16 Mirror holder 20 Rotating shaft (shaft) 21 One end 23 Other end 26 Preload spring 27 Stopper 28 Spacer 30 Magnet 32a, 32b pole 32c Magnetic pole switching section 40 Unit body 41 Core Assembly 42 1st Core 44 Second Core 46 3rd Core 48 Position holding part 50 Coil body 52, 54 Coil 52a, 54a Coil ends 56, 57 Bobbin 58 Terminals 60 Frame section 61 Base 62 Axis holder 64, 65 Bearings 66 Bearing housing 67 Substrate 69 Fixed hole 72 Sensor Board 74 Encoder Disk 76 Encoder Hub 77, 81, 86a, 87 Fastening members 78 Light Sensor 79, 616 Positioning pin 82 Positioning cover 84 Bottom cover 86b Attached member 87 Fastening members 420a, 420b End poles 421, 421a, 421b Rod-shaped body 422 Connection edge 423, 423a, 423b and the sides 424 Interpolator 561, 571 flange 563, 573 Holding part 612 Opening 614 Connection hole 624 Rising wall 626 Wall 626a Sensor housing 627 Insertion hole 800 Fixed base 804, 806 Fixed wall section

Claims

1. a movable body having a shaft portion with a magnet fixed to its outer periphery, holding a V-shaped mirror with a ridge portion of the V-shaped mirror aligned with the shaft portion, and supported so as to be rotatable back and forth around an axis via the shaft portion; a unit main body including: a plurality of magnetic poles facing the magnet in a radial direction of the shaft portion and spaced apart from one another in a circumferential direction of the shaft portion; a coil body forming, together with the magnet, an electromagnetic drive unit that rotates the movable body back and forth; and a magnetic body facing the magnet in the radial direction of the shaft portion and disposed between the plurality of magnetic poles in the circumferential direction, the magnetic body attracting the magnet and urging the movable body toward an initial position of the reciprocating rotation; having the electromagnetic driving unit reciprocally rotates the movable body to oscillate the V-shaped mirror while maintaining the angle formed by the V-shaped mirror; Rotary reciprocating drive actuator.

2. The shaft portion has an axis located at a center of gravity of the V-shaped mirror or at a position adjacent to the center of gravity, and fixes the V-shaped mirror.

2. The rotary reciprocating drive actuator of claim 1.

3. The axis of the shaft portion is located within a triangular region between imaginary lines connecting the two separated ends of the mirror portion arranged in a V-shape.

2. The rotary reciprocating drive actuator of claim 1.

4. The unit body is covered with a shaft support on one of its axially opposite surfaces, The shaft support rotatably supports the shaft portion.

2. The rotary reciprocating drive actuator of claim 1.

5. The number of the plurality of magnetic poles is two, the poles being arranged opposite each other with the magnet in between, The magnet has different magnetic poles arranged alternately in the circumferential direction on its outer circumferential surface, a magnetic pole switching portion of a magnetic pole provided on an outer periphery of the magnet is configured to be positioned at an angle facing a central portion of each of the plurality of magnetic poles in the circumferential direction when the magnet is positioned at an initial angle corresponding to the initial position; 2. The rotary reciprocating drive actuator of claim 1.

6. the unit body includes a core assembly having the plurality of magnetic poles, the coil body being disposed therein and surrounding the magnet in the radial direction; The core assembly is composed of a laminated core in which steel plates, which are magnetic bodies, are laminated.

2. The rotary reciprocating drive actuator of claim 1.

7. The coil body is configured to be surrounded on all four sides around the axis by the core assembly.

7. The rotary reciprocating actuator of claim 6.

8. a plate-shaped base portion that fixes the unit body at a back side and positions the V-shaped mirror on the front side via a rotation axis that protrudes to the front side through a through hole in a direction parallel to the axial direction; The base portion and the unit main body are positioned or fixed by a fastening member that is fastened in a direction parallel to the shaft portion.

2. The rotary reciprocating drive actuator of claim 1.

9. a rotation detection unit that is disposed on the opposite side of the unit body to the unit body and that detects rotation of one end of the shaft portion, the rotation detection unit being disposed on the opposite side of the unit body to the unit body in the axial direction of the V-shaped mirror; 2. The rotary reciprocating drive actuator of claim 1.

10. the rotation detection unit has a sensor substrate on which a sensor for detecting rotation of the one end portion is mounted, A wall portion rotatably supports one end of the shaft portion, The sensor substrate is detachably attached to the wall portion so as to cover the one end portion.

10. The rotary reciprocating drive actuator of claim 9.

11. The rotary reciprocating actuator according to claim 1 ; a light irradiation unit that irradiates the V-shaped mirror of the rotary reciprocating actuator with a scanning light; having Optical scanning device.

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