Motor

Abstract

To provide a motor capable of detecting a rotational angle with high accuracy.SOLUTION: A motor 1 comprises: a shaft 2; a rotor 3 supported by the shaft 2; a circuit board 4 having a surface facing the rotor 3 in a longitudinal direction of the shaft 2; a light emission part 5 provided on the surface of the circuit board 4; and a light reception part 6 provided on the surface of the circuit board 4. The light emission part 5 and the light reception part 6 are arranged in a radial direction so as to be separated from each other. A projection part 32 is provided on the surface of the rotation body 3 in the longitudinal direction of the shaft 2. The projection part 32 passes between the light emission part 5 and the light reception part 6 with rotation of the shaft 2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Conventionally, there is known a motor composed of a motor part, a shaft holding part, and a flange. The motor part is composed of a motor magnet, a drive coil, an upper yoke and a lower yoke for forming a gap G in the axial direction, and three hall elements installed in the circumferential direction for detecting the position of the rotating motor magnet and sequentially obtaining signals for switching the current to the drive coil (see Patent Document 1).

[0003] In this motor device, a plurality of magnetic sensors detect magnetic fluxes that change as the rotor rotates, and the rotation angle of the rotor is calculated based on the detection results.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, in the motor disclosed in Patent Document 1, hall elements were used to detect the position of a rotating body (polygon mirror) in the circumferential direction, but it was difficult to output signals from the hall elements in synchronization with the position of the rotating body in the circumferential direction.

[0006] The present invention takes the above problems as an example, and an object thereof is to provide a motor capable of accurately detecting a rotation angle.

Means for Solving the Problems

[0007] To achieve the above object, the motor according to the present invention includes a shaft, a rotating body supported by the shaft, a circuit board having a surface facing the rotating body in the longitudinal direction of the shaft, a light emitting portion provided on the surface of the circuit board, and a light receiving portion provided on the surface of the circuit board. The light emitting portion and the light receiving portion are arranged to be separated from each other in the radial direction, and a protruding portion is provided on the surface of the rotating body in the longitudinal direction of the shaft. The protruding portion passes between the light emitting portion and the light receiving portion as the shaft rotates.

[0008] In the motor according to one aspect of the present invention, the shape of the protruding portion is cylindrical, and through holes are formed on the outer peripheral surface of the protruding portion.

[0009] In the motor according to one aspect of the present invention, the shape of the protruding portion is cylindrical, and a plurality of through holes are formed at predetermined intervals in the circumferential direction on the outer peripheral surface of the protruding portion.

[0010] The motor according to one aspect of the present invention includes a housing having a base portion extending in the radial direction, and the circuit board is supported by the base portion.

[0011] The motor according to one aspect of the present invention includes a stator, and the circuit board is arranged between the rotating body and the stator in the longitudinal direction of the shaft.

[0012] The motor according to one aspect of the present invention includes a bearing, and the bearing is arranged inside the rotating body in the radial direction.

[0013] In the motor according to one aspect of the present invention, the shape of the protruding portion is a cylinder.

[0014] In order to achieve the above object, the motor according to the present invention includes a shaft, a rotating body supported by the shaft, a circuit board having a surface facing the rotating body in the longitudinal direction of the shaft, a light emitting portion provided on the surface of the circuit board, and a light receiving portion provided on the surface of the circuit board. In the longitudinal direction of the shaft, a protruding portion is provided on the surface of the rotating body, and in the radial direction, the light emitting portion and the light receiving portion are arranged to face the outer peripheral surface of the protruding portion. The outer peripheral surface of the protruding portion has a reflecting surface that reflects the light emitted from the light emitting portion to the light receiving portion.

[0015] According to the motor of the present invention, the rotation angle can be accurately detected.

Brief Description of Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0017] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

[0018] [1. First Embodiment] First, with reference to FIGS. 1 to 5, the configuration of a motor according to the first embodiment of the present invention will be described.

[0019] [1-1. Overall Configuration of the Motor] First, with reference to FIGS. 1 and 2, the overall configuration of a motor according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view schematically showing the configuration of a motor 1 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1.

[0020] Hereinafter, for convenience of explanation, in the axial direction of the axis x, the direction of arrow a is defined as the upper side a, and the direction of arrow b is defined as the lower side b. Also, in the direction perpendicular to the axis x (hereinafter also referred to as the "radial direction"), the direction away from the axis x (the direction of arrow c in FIG. 1) is defined as the outer peripheral side c, and the direction toward the axis x (the direction of arrow d in FIG. 1) is defined as the inner peripheral side d. And the circumferential direction around the axis x (the direction of arrow e in FIG. 1) is defined as the circumferential direction e.

[0021] As shown in FIG. 1, a motor 1 according to the first embodiment of the present invention includes a shaft 2 that rotates counterclockwise about an axis x, a rotating body 3 supported by the shaft 2, a circuit board 4 having a surface 4a facing the rotating body 3 (see FIG. 2), a light-emitting unit 5 provided on the surface 4a of the circuit board 4 that emits light (see FIG. 2), and a light-receiving unit 6 provided on the surface 4a of the circuit board 4 that receives light emitted from the light-emitting unit 5 (see FIG. 2).

[0022] Also, as shown in FIG. 2, the motor 1 has a housing 7 that houses the rotating body 3 and the circuit board 4 inside, and a stator 9 that surrounds the shaft 2.

[0023] The shaft 2 has an end 2a disposed on the upper side a in the longitudinal direction (hereinafter referred to as the axis x direction), and an end 2b disposed on the lower side b in the axis x direction, and rotates counterclockwise about the axis x. The upper side a portion of the shaft 2 protrudes upward from the hole 31 of the rotating body 3 described later to the upper side a.

[0024] [1-2. Structure of the Rotating Body] Next, with reference to FIGS. 2 and 3, the structure of the rotating body 3 will be described. FIG. 3 is a perspective view schematically showing the structure of the rotating body 3 of the motor 1.

[0025] As shown in FIGS. 2 and 3, the rotating body 3 has a bottom portion 30a and a cylindrical portion 30b, and has an upper surface 3a on the upper side a in the axis x direction, a surface 3b facing the surface 4a of the circuit board 4, an end surface 3e disposed on the circuit board 4 side, an outer peripheral surface 3c between the upper surface 3a and the end surface 3e and on the outer peripheral side c in the axis x direction, and an inner peripheral surface 3d between the upper surface 3a and the end surface 3e and on the inner peripheral side d in the axis x direction. The rotating body 3 rotates counterclockwise about the axis x as the shaft 2 rotates without contacting the circuit board 4.

[0026] As shown in FIG. 2, a hole 31 through which the upper side a portion of the shaft 2 in the axis x direction is inserted is formed in the upper surface 3a of the rotating body 3. The hole 31 has a cylindrical shape protruding upward in the axis x direction.

[0027] As shown in FIG. 3, in the axis x direction, a protrusion 32 is provided on the surface 3b of the rotating body 3. The shape of the protrusion 32 is cylindrical about the axis x and protrudes from the surface 3b toward the circuit board 4 (see FIG. 2). Further, the protrusion 32 is disposed on the inner peripheral side d from the inner peripheral surface 3d of the rotating body 3. The end surface 32a of the protrusion 32 on the circuit board 4 side is disposed so as to be spaced apart from the surface 4a of the circuit board 4 by a predetermined distance (see FIG. 2).

[0028] The protruding portion 32 is disposed on the lower side b in the axial direction x, and has a cylindrical lower portion 33 that passes between the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) as the shaft 2 rotates, and a cylindrical upper portion 34 disposed on the upper side a of the lower portion 33. The lower portion 33 and the upper portion 34 are part of the protruding portion 32 but are actually integrally arranged.

[0029] The lower portion 33 of the protruding portion 32 is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a (see FIG. 2) of the light receiving portion 6 to the end face 32a in a state where the end face 32a of the protruding portion 32 is disposed to face the circuit board 4. The lower portion 33 of the protruding portion 32 is arranged so as to be spaced apart from the light emitting portion 5 and the light receiving portion 6 by a predetermined distance. When the shaft 2 rotates, the lower portion 33 of the protruding portion 32 passes between the light emitting portion 5 and the light receiving portion 6 without contacting the light emitting portion 5 and the light receiving portion 6 as the shaft 2 rotates.

[0030] The upper portion 34 of the protruding portion 32 is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a (see FIG. 2) to the surface 3b of the rotating body 3 in a state where the end face 32a of the protruding portion 32 is disposed to face the circuit board 4.

[0031] As shown in FIG. 3, a rectangular through hole 35 through which the light emitted from the light emitting portion 5 passes is formed in the outer peripheral surface 32c on the outer peripheral side c of the protruding portion 32 in the circumferential direction e.

[0032] The through hole 35 penetrates from the outer peripheral surface 32c on the outer peripheral side c of the protruding portion 32 to the inner peripheral surface 32d on the inner peripheral side d. Further, a plurality of (four in the first embodiment of the present invention) through holes 35 are formed at equal intervals on the outer peripheral surface 32c of the protruding portion 32.

[0033] Note that although the description will be given for the case where the through holes 35 are formed in the lower portion 33 and the upper portion 34 of the protruding portion 32, it is sufficient that at least a part of the through holes 35 is formed in the lower portion 33 of the protruding portion 32, and they may be formed only in the lower portion 33 of the protruding portion 32.

[0034] [1-3. Configuration of Circuit Board] Next, with reference to FIGS. 4 and 5, the configuration of the circuit board 4 will be described. FIG. 4 is a perspective view showing a state in which the circuit board 4 of the motor 1 and the housing 7 are separated. FIG. 5 is a perspective view showing a state in which the circuit board 4 of the motor 1 and the housing 7 are assembled.

[0035] As shown in FIG. 4, the circuit board 4 extends in the radial direction and has a surface 4a on the side of the rotating body 3, a surface 4b on the side of the stator 9 which is the surface facing the stator 9, and a pair of side surfaces 4c and a pair of side surfaces 4d on the outer peripheral side c between the surface 4a and the surface 4b. The pair of side surfaces 4c extends in the radial direction. The pair of side surfaces 4d face in a direction substantially perpendicular to the pair of side surfaces 4c. The circuit board 4 is disposed between the rotating body 3 and the stator 9 in the axial direction x of the shaft 2 (see FIG. 2).

[0036] As shown in FIG. 5, a light emitting portion 5 and a light receiving portion 6 are provided on the surface 4a of the circuit board 4. The light emitting portion 5 and the light receiving portion 6 are arranged to be separated from each other in the radial direction. Specifically, the light emitting portion 5 is arranged on the outer peripheral side c, and the light receiving portion 6 is arranged on the inner peripheral side d.

[0037] The light emitting portion 5 and the light receiving portion 6 are optical sensors. The light emitting portion 5 is a light source such as an infrared LED (Light Emitting Diode) or a semiconductor laser. The light receiving portion 6 is a photodiode, a phototransistor, or the like.

[0038] As shown in FIG. 4, the circuit board 4 has a hole 41 into which a boss 77 of a housing 7 (to be described later) is inserted, an edge portion 42 which is an edge portion of the hole 41, and a hole 43 through which the shaft 2 and a hole 79 of the housing 7 (to be described later) are inserted. The edge portion 42 is formed in a shape protruding toward the stator 9 side.

[0039] A plurality of holes 41 (two in the first embodiment of the present invention) are formed in the circuit board 4. The holes 41 are respectively formed near a pair of side surfaces 4c and penetrate from the surface 4a of the circuit board 4 to the surface 4b of the circuit board 4. When a boss 77 of the housing 7 (to be described later) is inserted into the hole 41, the circuit board 4 is disposed between the rotating body 3 and the stator 9 in the longitudinal direction (axis x direction) of the shaft 2 (see FIG. 2).

[0040] The edge portion 42 protrudes from the side surface 4c toward the outer peripheral side c. When a boss 77 of the housing 7 (to be described later) is inserted into the hole 41, the edge portion 42 contacts an edge portion 78 of the housing 7.

[0041] The hole 43 is formed at the center or substantially at the center of the circuit board 4 and penetrates from the surface 4a of the circuit board 4 to the surface 4b of the circuit board 4.

[0042] [1-4. Configuration of Housing] Next, with reference to FIGS. 2, 4, and 5, the configuration of the housing 7 will be described.

[0043] As shown in FIG. 5, the housing 7 has an upper housing 71 disposed on the upper side a in the axis x direction and covering the outer peripheral surface 3c of the rotating body 3, and a lower housing 72 disposed on the lower side b in the axis x direction and accommodating the stator 9.

[0044] As shown in Fig. 4, the upper housing 71 has an end face 71a disposed on the upper side a in the axial direction of the axis x, a lower face 71b that is disk-shaped or substantially disk-shaped centered on the axis x and disposed on the lower side b of the end face 71a, and an outer peripheral face 71c that is between the end face 71a and the lower face 71b and on the outer peripheral side c in the axial direction of the axis x. The outer peripheral face 71c is disposed on the outer peripheral side c of the outer peripheral face 3c of the rotating body 3.

[0045] The lower face 71b of the upper housing 71 has a bottom face 73 on the rotating body 3 side that is disposed on the upper side a in the axial direction of the axis x and faces the rotating body 3, and a bottom face 74 on the circuit board 4 side that is disposed on the lower side b in the axial direction of the axis x and faces the circuit board 4.

[0046] As shown in Fig. 5, holes 75 for exposing the light emitting portion 5 and the light receiving portion 6 are formed in the lower face 71b of the upper housing 71. The holes 75 are formed such that the light emitting portion 5 and the light receiving portion 6 disposed on the face 4a of the circuit board 4 can be inserted from the lower side b to the upper side a in the axial direction of the axis x when the circuit board 4 is fixed to the upper housing 71. Specifically, the holes 75 penetrate from the bottom face 73 on the rotating body side to the bottom face 74 on the circuit board 4 side.

[0047] As shown in Fig. 4, the bottom face 74 on the circuit board 4 side has a base portion 76 extending in the radial direction, a boss 77 having a cylindrical shape or a substantially cylindrical shape, an edge portion 78 that contacts the edge portion 42 of the circuit board 4, and a hole portion 79 in which a cylindrical or substantially cylindrical insertion hole 79h through which the shaft 2 is inserted is formed.

[0048] The base portion 76 has claws 80a, 80b for locking a pair of side faces 4d of the circuit board 4 at both ends in the radial direction. The boss 77 protrudes downward b in the axial direction of the axis x from the bottom face 74 on the circuit board 4 side. When a pair of side faces 4d of the circuit board 4 are locked to the claws 80a, 80b and the boss portion 44 is inserted into the hole portion 41 of the circuit board 4, the circuit board 4 is supported with respect to the base portion 76. At this time, the edge portion 78 contacts the edge portion 42 of the circuit board 4.

[0049] The hole portion 79 extends downward b in the axial direction x from the bottom surface 74 on the circuit board side, and when the circuit board 4 is supported by the base portion 76, it is inserted into the hole portion 43 of the circuit board 4.

[0050] As shown in FIG. 2, the upper housing 71 and the lower housing 72 are connected by inserting a protrusion 7a formed on the outer peripheral side c of the upper housing 71 into a hole 7b formed in the lower housing 72.

[0051] Inside the upper housing 71 and the lower housing 72, a rotor 8 including a shaft 2 and a stator 9 surrounding the rotor 8 are accommodated. Also, inside the housing 7, there are a bearing 81a that rotatably supports the upper a portion of the shaft 2 in the axial direction x and a bearing 81b that rotatably supports the lower b portion of the shaft 2 in the axial direction x.

[0052] The bearing 81a and the bearing 81b are arranged inside the rotating body 3 in the radial direction. Specifically, the bearing 81a and the bearing 81b are below the upper surface 3a of the rotating body 3 and on the inner peripheral side d of the protruding portion 32 of the rotating body 3. They are arranged on the inner peripheral side d of the protruding portion 32 of the rotating body 3.

[0053] The rotor 8 has a shaft 2, a core 83 formed annularly so as to surround the shaft 2, and a magnet 84 formed annularly so as to surround the outer peripheral side c surface of the core 83. The upper a portion of the shaft 2 is inserted into the hole portion 31. A bush 82 is attached between the outer peripheral side c surface of the shaft 2 and the inner peripheral side d surface of the hole portion 31.

[0054] The stator 9 has a stator core 91 formed annularly so as to surround the rotor 8, a coil 92 wound around an extending portion (not shown) extending from the stator core 91 to the inner peripheral side d, and an insulator (not shown) that insulates the stator core 91 and the coil 92.

[0055] [1-5. Method for Detecting Rotation Position] Next, a method for detecting the rotation position of the motor 1 will be described.

[0056] When the shaft 2 rotates counterclockwise about the axis x by the rotor 8 and the stator 9, the rotating body 3 supported by the shaft 2 also rotates counterclockwise.

[0057] When the rotating body 3 rotates, the lower portion 33 of the protruding portion 32 passes between the light emitting portion 5 and the light receiving portion 6 without contacting them. At this time, since the through hole 35 formed in the protruding portion 32 passes between the light emitting portion 5 and the light receiving portion 6 as the rotating body 3 rotates, the light receiving portion 6 detects the presence or absence of light reception from the light emitting portion 5. That is, when the through hole 35 passes between the light emitting portion 5 and the light receiving portion 6, the light receiving portion 6 receives the light from the light emitting portion 5. Also, when the portion of the lower portion 33 of the protruding portion 32 other than the through hole 35 faces the light emitting portion 5 and the light receiving portion 6, the light from the light emitting portion 5 is blocked, so the light receiving portion 6 cannot receive the light from the light emitting portion 5. In this way, the presence or absence of light reception occurs, and based on the light reception timing, the rotation angle (rotation position), rotation speed, and rotation speed of the shaft 2 are detected via a control unit (not shown) or the like.

[0058] In this way, in the motor 1, the protruding portion 32 of the rotating body 3 passes between the light emitting portion 5 and the light receiving portion 6, and the rotation position of the shaft 2 is detected based on the light reception timing of the light from the light emitting portion 5 received by the light receiving portion 6. Therefore, compared with the case where the rotation position is detected by detecting the magnetic flux that changes as the shaft 2 rotates, the change in the environmental temperature does not affect the detection accuracy of the rotation angle, and the rotation angle can be detected accurately.

[0059] Further, since the circuit board 4 provided with the light emitting portion 5 and the light receiving portion 6 is supported by the base portion 76 of the housing 7, the light emitting portion 5 and the light receiving portion 6 can be horizontally arranged in the radial direction. In particular, by inserting the boss of the base portion 76 into the hole portion 41 of the circuit board 4, the circuit board 4 can be easily supported by the base portion 76 and can be easily arranged horizontally.

[0060] Furthermore, since it has claws 80a and 80b for locking a pair of side surfaces 4c of the circuit board 4, it is possible to maintain the state in which the circuit board 4 is horizontally arranged in the radial direction of the rotating body 3.

[0061] In addition, since the circuit board 4 provided with the light emitting part 5 and the light receiving part 6 is arranged between the rotating body 3 and the stator 9 in the axial direction of the axis x, it is possible to easily adjust the phases of the shaft 2 and the rotating body 3.

[0062] And the bearings 81a and 81b are arranged on the lower side b in the axial direction of the axis x from the upper surface 3a of the rotating body 3 and on the inner circumferential side d of the protruding part 32 of the rotating body 3. For this reason, the height in the axial direction of the axis x of the motor 1 can be lowered and the whole can be made compact.

[0063] In the first embodiment of the present invention described above, the case where a plurality of through holes 35 through which the light emitted from the light emitting part 5 passes are formed on the outer peripheral surface 32c of the protruding part 32 has been described. However, only one through hole 35 may be formed on the outer peripheral surface 32c. In this case, the light receiving part 6 can detect the rotational speed and the rotational velocity of the shaft 2 based on the light receiving timing of the light from the light emitting part 5.

[0064] [1-6. Modification Example] Next, with reference to FIG. 6, a first modification example and a second modification example of the rotating body 3 of the motor 1 according to the first embodiment described above will be described. FIG. 6 is a diagram for showing a modification example of the rotating body 3 of the motor 1. FIG. 6(a) is a perspective view of a rotating body 103a for showing a first modification example in the motor 1, and FIG. 6(b) is a perspective view of a rotating body 103b for showing a second modification example in the motor 1. Hereinafter, the same reference numerals will be given to the same or similar configurations as those of the motor 1 according to the first embodiment described above, and the description thereof will be omitted.

[0065] As shown in FIG. 6(a), the rotating body 103a has a protruding portion 132a that protrudes from the surface 3b facing the surface 4a of the circuit board 4 toward the circuit board 4 side (see FIG. 2). The protruding portion 132a has a cylindrical shape. This protruding portion 132a is disposed on the inner peripheral side d from the inner peripheral surface 3d of the rotating body 3.

[0066] A plurality (four in this first modified example) of the protruding portions 132a are arranged at equal intervals in the circumferential direction e centered on the axis x. That is, the plurality of protruding portions 132a are arranged at equal angular (90 degrees in this first modified example) intervals about the axis x.

[0067] Further, the protruding portion 132a is disposed on the lower side b in the direction of the axis x, and has a lower portion 133a that passes between the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) as the shaft 2 rotates, and an upper portion 134a disposed on the upper side a in the direction of the axis x of the lower portion 133a. The lower portion 133a and the upper portion 134a are part of the protruding portion 132a but are actually integrally arranged.

[0068] The lower portion 133a of the protruding portion 132a is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a (see FIG. 2) of the light receiving portion 6 to the end face 130a in a state where the end face 130a of the protruding portion 132a is disposed to face the circuit board 4. The lower portion 133a of the protruding portion 132a is arranged so as to be spaced apart from the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) by a predetermined distance. When the shaft 2 rotates, the lower portion 133a of the protruding portion 132a passes between the light emitting portion 5 and the light receiving portion 6 without contacting the light emitting portion 5 and the light receiving portion 6 as the shaft 2 rotates.

[0069] The upper portion 134a of the protruding portion 132a is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a of the light receiving portion 6 (see FIG. 2) to the surface 3b of the rotating body 103a in a state where the end face 130a of the protruding portion 132a is disposed to face the circuit board 4.

[0070] When the rotating body 103a rotates as the shaft 2 rotates, the lower portion 133a of the protruding portion 132a passes between the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) without contacting the light emitting portion 5 and the light receiving portion 6. At this time, the light receiving portion 6 detects the presence or absence of light reception from the light emitting portion 5. That is, when the protruding portion 132a does not pass between the light emitting portion 5 and the light receiving portion 6, the light receiving portion 6 receives the light from the light emitting portion 5. When the lower portion 133a of the protruding portion 132a passes through the light emitting portion 5 and the light receiving portion 6, the light from the light emitting portion 5 is blocked, so that the light receiving portion 6 cannot receive the light from the light emitting portion 5. In this way, the presence or absence of light reception occurs, and based on the light reception timing, the rotation angle (rotation position), rotation speed, and rotation speed of the shaft 2 are detected via a control unit (not shown) or the like.

[0071] In the above-described first modification, the case where a plurality of protruding portions 132a are arranged on the rotating body 103a has been described. However, only one protruding portion 132a may be arranged on the rotating body 103a. Further, although the case where the protruding portion 132a has a cylindrical shape has been described, it may have a square prism shape, a triangular prism shape, a cylindrical shape, or the like.

[0072] As shown in FIG. 6(b), the rotating body 103b has a protruding portion 132b that protrudes from the surface 3b facing the surface 4a of the circuit board 4 toward the circuit board 4 (see FIG. 2). The shape of the protruding portion 132b is a cylindrical shape centered on the axis x. This protruding portion 132b is arranged on the inner peripheral side d of the inner peripheral surface 3d of the rotating body 3.

[0073] The protruding portion 132b is formed with notches 135b that are cut out from the end face 130b toward the surface 3b. A plurality (four in this first modification) of the notches 135b are formed at equal intervals around the axis x.

[0074] Further, the protruding portion 132b is disposed on the lower side b in the axial direction of the axis x, and includes a lower portion 133b that passes between the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) as the shaft 2 rotates, and an upper portion 134b that is disposed on the upper side a in the axial direction of the axis x of the lower portion 133b. The lower portion 133b and the upper portion 134b are part of the protruding portion 132b but are actually integrally arranged.

[0075] The lower portion 133b of the protruding portion 132b is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a (see FIG. 2) of the light receiving portion 6 to the end face 130b in a state where the end face 130b of the protruding portion 132b is disposed to face the circuit board 4. The lower portion 133b of the protruding portion 132b is arranged so as to be spaced apart from the light emitting portion 5 and the light receiving portion 6 (see FIG. 2) by a predetermined distance. When the shaft 2 rotates, the lower portion 133b of the protruding portion 132b passes between the light emitting portion 5 and the light receiving portion 6 without contacting the light emitting portion 5 and the light receiving portion 6 as the shaft 2 rotates.

[0076] The upper portion 134b of the protruding portion 132b is the portion from the position facing the tip 5a (see FIG. 2) of the light emitting portion 5 and the tip 6a of the light receiving portion 6 (see FIG. 2) to the surface 3b of the rotating body 103b in a state where the end face 130b of the protruding portion 132b is disposed to face the circuit board 4.

[0077] When the rotating body 103b rotates as the shaft 2 rotates, the lower portion 133b of the protruding portion 132b passes between the light emitting portion 5 (see FIG. 2) and the light receiving portion 6 (see FIG. 2) without contacting them. At this time, since the notch 135b formed in the protruding portion 132b passes between the light emitting portion 5 and the light receiving portion 6 as the rotating body 103b rotates, the light receiving portion 6 detects the presence or absence of light reception from the light emitting portion 5. That is, when the notch 135b passes between the light emitting portion 5 and the light receiving portion 6, the light receiving portion 6 receives the light from the light emitting portion 5. Also, when a portion of the lower portion 133b of the protruding portion 132b other than the notch 135b faces the light emitting portion 5 and the light receiving portion 6, the light from the light emitting portion 5 is blocked, so the light receiving portion 6 cannot receive the light from the light emitting portion 5. In this way, the presence or absence of light reception occurs, and based on the light reception timing, the rotation angle (rotation position), rotation speed, and rotation rate of the shaft 2 are detected via a control unit (not shown) or the like.

[0078] In the above-described second modification, the case where a plurality of notches 135b are formed in the protruding portion 132b has been described, but only one notch 135b may be formed in the protruding portion 132b.

[0079] [2. Second Embodiment] Next, with reference to FIGS. 7 and 8, the configuration of the motor according to the second embodiment of the present invention will be described. FIG. 7 is a perspective view schematically showing the configuration of the rotating body 203 of the motor according to the second embodiment of the present invention. FIG. 8 is a perspective view schematically showing the configuration of the circuit board 4 and the housing 207 of the motor according to the second embodiment of the present invention. Hereinafter, the same reference numerals will be given to the configurations that are the same as or similar to those of the motor 1 according to the first embodiment described above, and the description thereof will be omitted.

[0080] As shown in FIG. 7, the rotating body 203 has a protruding portion 232 that protrudes from the surface 3b facing the surface 4a of the circuit board 4 toward the circuit board 4 side. The shape of the protruding portion 232 is cylindrical with the axis x as the center. This protruding portion 232 is disposed on the inner peripheral side d from the inner peripheral surface 3d of the rotating body 203.

[0081] The protruding portion 232 is disposed on the lower side b in the axial direction of the axis x, and has a cylindrical lower portion 233 that passes through the inner peripheral side d of the light emitting portion 205 and the light receiving portion 206 (see FIG. 8) described later as the shaft 2 rotates, and a cylindrical upper portion 234 disposed on the upper side a of the lower portion 233. The lower portion 233 and the upper portion 234 are part of the protruding portion 232 but are actually integrally arranged.

[0082] The lower portion 233 of the protruding portion 232 is the portion from the position facing the tip 205a (see FIG. 8) of the light emitting portion 205 and the tip 206a (see FIG. 8) of the light receiving portion 206 to the end face 230 in a state where the end face 230 of the protruding portion 232 is disposed to face the circuit board 4. The lower portion 233 of the protruding portion 232 is arranged so as to be spaced apart from the light emitting portion 205 and the light receiving portion 206 by a predetermined distance. When the shaft 2 rotates, the lower portion 233 of the protruding portion 232 rotates on the inner peripheral side d of the light emitting portion 205 and the light receiving portion 206 without contacting the light emitting portion 205 and the light receiving portion 206 as the shaft 2 rotates.

[0083] The upper portion 234 of the protruding portion 232 is the portion from the position where the tip 205a (see FIG. 8) of the light emitting portion 205 and the tip 206a (see FIG. 8) of the light receiving portion 6 face each other to the surface 3b of the rotating body 3 in a state where the end face 230 of the protruding portion 232 is disposed to face the circuit board 4.

[0084] As shown in FIG. 7, the outer peripheral surface 32c on the outer peripheral side c of the protruding portion 232 has a rectangular reflecting surface 235 that reflects the light emitted from the light emitting portion 205. A plurality of reflecting surfaces 235 (four in the second embodiment of the present invention) are arranged at equal intervals.

[0085] As shown in FIG. 8, the light emitting portion 205 and the light receiving portion 206 are provided on the surface 4a of the circuit board 4 (see FIG. 2). The light emitting portion 205 and the light receiving portion 206 are arranged to face the outer peripheral surface 32c of the protruding portion 232 along the radial direction.

[0086] The housing 207 has an upper housing 271 disposed on the upper side a in the axial direction x to cover the outer peripheral surface 3c of the rotating body 203, and a lower housing 72 disposed on the lower side b in the axial direction x to accommodate the stator 9 (see FIG. 2).

[0087] The lower surface 271b of the upper housing 271 has a bottom surface 273 on the rotating body 3 side disposed on the upper side a in the axial direction x and facing the rotating body 203, and a bottom surface 274 on the circuit board 4 side disposed on the lower side b in the axial direction x and facing the circuit board 4 (see FIG. 2).

[0088] On the lower surface 271b of the upper housing 271, a hole 275 for exposing the light emitting part 205 and the light receiving part 206 is formed. The hole 275 is formed so that the light emitting part 205 and the light receiving part 206 arranged on the surface 4a of the circuit board 4 can be inserted from the lower side b to the upper side a in the axial direction x when the circuit board 4 is fixed to the upper housing 2 71. Specifically, the hole 275 is formed to penetrate from the bottom surface 273 on the rotating body 3 side to the bottom surface 274 on the circuit board 4 side.

[0089] When the rotating body 203 rotates, the lower portion 233 of the protruding portion 232 rotates on the inner peripheral side d of the light emitting part 205 and the light receiving part 206 without contacting the light emitting part 205 and the light receiving part 206. At this time, as the reflecting surface of the protruding portion 232 passes through the inner peripheral side d of the light emitting part 205 and the light receiving part 206 as the rotating body 203 rotates, the light receiving part 206 detects the presence or absence of light reception from the light emitting part 205. That is, when the reflecting surface 235 faces the light emitting part 205 and the light receiving part 206, the light receiving part 206 receives the light from the light emitting part 205. Also, when a portion other than the reflecting surface 235 of the lower portion 233 of the protruding portion 232 faces the light emitting part 205 and the light receiving part 206, the light receiving part 206 cannot receive the light from the light emitting part 205. In this way, the presence or absence of light reception occurs, and based on the light reception timing, the rotation angle (rotation position), rotation speed, and rotation speed of the shaft 2 are detected via a control unit (not shown) or the like.

[0090] In this way, in the motor 1, the protruding portion 232 of the rotating body 203 passes through the inner peripheral side d of the light emitting portion 205 and the light receiving portion 206, and the rotation position of the shaft 2 (see FIG. 2) is detected by the light reception timing of the light from the light emitting portion 205 received by the light receiving portion 206. Therefore, compared with the case where the rotation position is detected by detecting the magnetic flux that changes as the shaft 2 rotates, the change in the environmental temperature does not affect the detection accuracy of the rotation angle, and the rotation angle can be detected with high accuracy.

[0091] In addition, in the second embodiment described above, the case where a plurality of reflecting surfaces 235 are arranged on the outer peripheral surface 32c of the protruding portion 232 has been described. However, one reflecting surface 235 may be arranged on the outer peripheral surface 32cc of the protruding portion 232. Further, the outer peripheral surface 32c of the protruding portion 232 may be a non-reflecting surface that is a reflecting surface and does not reflect the light from the light emitting portion 205 to the light receiving portion 206.

[0092] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the motor 1 according to the above embodiments of the present invention, and includes all aspects included in the concept and claims of the present invention. Further, each configuration may be selectively combined as appropriate so as to achieve at least part of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment can be appropriately changed according to the specific usage mode of the present invention.

[0093] Note that the shape of the rotating bodies 3 and 203 according to the first and second embodiments of the present invention can be appropriately changed as long as the protruding portions 32 and 232 of the rotating bodies 3 and 203 face the light emitting portions 5 and 205 and the light receiving portions 6 and 206, so that the presence or absence of light reception from the light emitting portion 205 of the light receiving portion 206 occurs.

Explanation of Reference Numerals

[0094] 1... motor, 2... shaft, 2a, 2b... ends, 3... rotating body, 3a... upper surface, 3b... surface, 3c... outer peripheral surface, 3d... inner peripheral surface, 3e... end face, 4... circuit board, 4a... surface on the rotating body side, 4b... surface on the stator side, 4c, 4d... side surfaces, 5... light emitting part, 5a... tip, 6... light receiving part, 6a... tip, 7... housing, 7a... protrusion, 7b... hole, 8... rotor, 9... stator, 30a... bottom, 30b... cylindrical part, 31... hole part, 32... protruding part, 32a... end face, 32c... outer peripheral surface, 32d... inner peripheral surface, 33... lower part, 34... upper part, 35... through hole, 36... boundary, 41... hole part, 42... edge part, 43... hole part, 71... upper housing, 71a... end face, 71b... lower surface, 71c... outer peripheral surface, 72... lower housing, 73... bottom surface on the rotating body side, 74... bottom surface on the circuit board side, 75... hole, 76... base part, 77... boss, 78... edge part, 79... hole part, 79h... insertion hole, 80a, 80b... claws, 81a, 81b... bearings, 82... bush, 83... core, 84... magnet, 91... stator core, 92... coil, 103a... rotating body, 103b... rotating body, 130a... end face, 130b... end face, 132a... protruding part, 132b... protruding part, 133a... lower part, 133b... lower part, 134a... upper part, 134b... upper part, 135b... notch, 203... rotating body, 205... light emitting part, 205a... tip, 206... light receiving part, 206a... tip, 207... housing, 230... end face, 232... protruding part, 233... lower part, 234... upper part, 235... reflecting surface, 236... boundary, 271... upper housing, 271b... lower surface, 273... bottom surface on the rotating body side, 274... bottom surface on the circuit board side, 275... hole, a... upper side, b... lower side, c... outer peripheral side, d... inner peripheral side, e... circumferential direction

Claims

1. A shaft, A rotor supported by the shaft; a circuit board having a surface facing the rotor in a longitudinal direction of the shaft; a light emitting portion provided on the surface of the circuit board; a light receiving unit provided on the surface of the circuit board, The light emitting unit and the light receiving unit are disposed apart from each other in a radial direction, A protrusion is provided on a surface of the rotor in the longitudinal direction of the shaft, A motor, wherein the protrusion passes between the light emitting portion and the light receiving portion as the shaft rotates.

2. The shape of the protrusion is cylindrical, The motor according to claim 1 , wherein a through hole is formed in an outer peripheral surface of the protrusion.

3. The shape of the protrusion is cylindrical, The motor according to claim 1 , wherein a plurality of through holes are formed in an outer circumferential surface of the protruding portion at predetermined intervals in a circumferential direction.

4. a housing having a radially extending base; 4. The motor according to claim 1, wherein the circuit board is supported on the base portion.

5. A stator is provided. The motor according to claim 1 , wherein the circuit board is disposed between the rotor and the stator in the longitudinal direction of the shaft.

6. A bearing is provided. The motor according to claim 1 , wherein the bearing is disposed radially inside the rotor.

7. The motor according to claim 1 , wherein the protrusion has a cylindrical shape.

8. A shaft, A rotor supported by the shaft; a circuit board having a surface facing the rotor in a longitudinal direction of the shaft; A light emitting portion provided on a surface of the circuit board; a light receiving unit provided on the surface of the circuit board, A protrusion is provided on a surface of the rotor in the longitudinal direction of the shaft, In the radial direction, the light emitting portion and the light receiving portion are disposed opposite to an outer circumferential surface of the protruding portion, The outer peripheral surface of the protrusion has a reflective surface that reflects light emitted from the light emitting portion to the light receiving portion.

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