motor

Abstract

A motor capable of detecting a rotation angle with high accuracy is provided. [Solution] The motor 1 comprises a shaft 2, a rotating body 3 supported by the shaft 2, a circuit board 4 having a surface facing the rotating body 3 in the longitudinal direction of the shaft 2, a light-emitting unit 5 provided on the surface of the circuit board 4, and a light-receiving unit 6 provided on the surface of the circuit board 4, the light-emitting unit 5 and the light-receiving unit 6 being arranged radially spaced apart from each other, and a protrusion 32 is provided on the surface of the rotating body 3 in the longitudinal direction of the shaft 2, and the protrusion 32 passes between the light-emitting unit 5 and the light-receiving unit 6 as the shaft 2 rotates.

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Conventionally, a motor is known that is composed of a motor section, a shaft holding section, and a flange. The motor section 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 circumferentially to detect the position of the rotating motor magnet and sequentially obtain signals for current switching to the drive coil (see Patent Document 1).

[0003] In this motor device, a magnetic flux that changes with the rotation of the rotor is detected by a plurality of magnetic sensors, and the rotation angle of the rotor is calculated based on the detection result.

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, although hall elements were used to detect the position of a rotating body (polygon mirror) in the circumferential direction, 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 objective, the motor according to the present invention comprises 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 part provided on the surface of the circuit board, and a light-receiving part provided on the surface of the circuit board, wherein the light-emitting part and the light-receiving part are spaced apart from each other in the radial direction, and a protrusion is provided on the surface of the rotating body in the longitudinal direction of the shaft, and the protrusion passes between the light-emitting part and the light-receiving part as the shaft rotates.

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

[0009] In a 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 on the outer circumferential surface of the protruding portion at predetermined intervals in the circumferential direction.

[0010] In one aspect of the present invention, a motor is provided with a housing having a radially extending base portion, the circuit board being supported on the base portion.

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

[0012] In a motor according to one aspect of the present invention, a bearing is provided, wherein the bearing is arranged radially inside the rotating body.

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

[0014] To achieve the above objective, the motor according to the present invention comprises 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 part provided on the surface of the circuit board, and a light-receiving part provided on the surface of the circuit board, wherein a protrusion is provided on the surface of the rotating body in the longitudinal direction of the shaft, and in the radial direction, the light-emitting part and the light-receiving part are arranged facing the outer circumferential surface of the protrusion, and the outer circumferential surface of the protrusion has a reflective surface that reflects light emitted from the light-emitting part to the light-receiving part.

[0015] According to the motor of the present invention, the rotation angle can be detected with high accuracy. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic perspective view showing the configuration of a motor according to the first embodiment of the present invention. [Figure 2] Figure 1, AA is a schematic cross-sectional view showing the configuration of a motor according to the first embodiment of the present invention. [Figure 3] This is a schematic perspective view showing the configuration of the rotating body of a motor according to the first embodiment of the present invention. [Figure 4] This is a perspective view showing the circuit board and housing of a motor according to the first embodiment of the present invention in a separated state. [Figure 5] This is a perspective view showing the assembled circuit board and housing of a motor according to the first embodiment of the present invention. [Figure 6] These figures illustrate modified versions of the rotating body of a motor according to the first embodiment of the present invention. Figure 6(a) is a perspective view showing a first modified version of the rotating body, and Figure 6(b) is a perspective view showing a second modified version of the rotating body. [Figure 7] This is a schematic perspective view showing the configuration of the rotating body of a motor according to a second embodiment of the present invention. [Figure 8] This is a schematic perspective view showing the configuration of the circuit board and housing of a motor according to a second embodiment of the present invention.

Mode for Carrying Out the Invention

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

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

[0019] [1-1. Overall Configuration of the Motor] First, referring to FIGS. 1 and 2, the overall configuration of the motor according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view schematically showing the configuration of the 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 the arrow a is defined as the upper side a, and the direction of the 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 the arrow c in FIG. 1) is defined as the outer peripheral side c, and the direction toward the axis x (the direction of the arrow d in FIG. 1) is defined as the inner peripheral side d. And the circumferential direction centered on the axis x (the direction of the arrow e in FIG. 1) is defined as the circumferential direction e.

[0021] As shown in FIG. 1, the motor 1 according to the first embodiment of the present invention includes a shaft 2 that rotates counterclockwise around the 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 portion 5 provided on the surface 4a of the circuit board 4 that emits light (see FIG. 2), and a light receiving portion 6 provided on the surface 4a of the circuit board 4 that receives the light emitted from the light emitting portion 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 located on the upper side a in the longitudinal direction (hereinafter referred to as the axis x direction) and an end 2b located on the lower side b in the axis x direction, and rotates counterclockwise about axis x. The upper side a portion of the shaft 2 protrudes upward from the hole 31 of the rotating body 3, which will be described later.

[0024] [1-2. Structure of a solid of revolution] Next, the configuration of the rotating body 3 will be described with reference to Figures 2 and 3. Figure 3 is a schematic perspective view showing the configuration of the rotating body 3 of the motor 1.

[0025] As shown in Figures 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 axial x direction, a surface 3b facing the surface 4a of the circuit board 4, an end surface 3e positioned on the circuit board 4 side, an outer surface 3c located between the upper surface 3a and the end surface 3e and on the outer side c in the axial x direction, and an inner surface 3d located between the upper surface 3a and the end surface 3e and on the inner side d in the axial x direction. The rotating body 3 rotates counterclockwise around the axis x as the shaft 2 rotates without contacting the circuit board 4.

[0026] As shown in Figure 2, a hole 31 is formed in the upper surface 3a of the rotating body 3 through which the upper part a in the axial x direction of the shaft 2 is inserted. The hole 31 has a cylindrical shape that protrudes upward a in the axial x direction.

[0027] As shown in Figure 3, a projection 32 is provided on the surface 3b of the rotating body 3 in the axial x direction. The projection 32 is cylindrical with axis x as its center and protrudes from surface 3b toward the circuit board 4 (see Figure 2). The projection 32 is also positioned on the inner side d of the inner circumferential surface 3d of the rotating body 3. The end face 32a of this projection 32 on the circuit board 4 side is positioned to be separated from the surface 4a of the circuit board 4 by a predetermined distance (see Figure 2).

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

[0029] The lower portion 33 of the protrusion 32 is the portion from the position facing the tip 5a of the light-emitting part 5 (see Figure 2) and the tip 6a of the light-receiving part 6 (see Figure 2) to the end face 32a, when the end face 32a of the protrusion 32 is positioned facing the circuit board 4. The lower portion 33 of the protrusion 32 is positioned at a predetermined distance from the light-emitting part 5 and the light-receiving part 6. When the shaft 2 rotates, the lower portion 33 of the protrusion 32 passes between the light-emitting part 5 and the light-receiving part 6 without coming into contact with them as the shaft 2 rotates.

[0030] The upper portion 34 of the protruding portion 32 faces the end face 32a of the protruding portion 32 toward the circuit board 4. In the arranged configuration, this refers to the portion from the position opposite the tip 5a of the light-emitting part 5 (see Figure 2) and the tip 6a of the light-receiving part 6 (see Figure 2) to the surface 3b of the rotating body 3.

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

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

[0033] The description will focus on the case where the through-hole 35 is formed in the lower portion 33 and the upper portion 34 of the protruding portion 32. However, it is sufficient that at least a part of the through-hole 35 is formed in the lower portion 33 of the protruding portion 32, or it may be formed only in the lower portion 33 of the protruding portion 32.

[0034] [1-3. Circuit Board Configuration] Next, the configuration of the circuit board 4 will be described with reference to Figures 4 and 5. Figure 4 is a perspective view showing the motor 1's circuit board 4 and housing 7 separated. Figure 5 is a perspective view showing the motor 1's circuit board 4 and housing 7 assembled.

[0035] As shown in Figure 4, the circuit board 4 extends radially and has a surface 4a on the rotating body 3 side, a surface 4b on the stator 9 side which is opposite the stator 9, and a pair of side surfaces 4c and a pair of side surfaces 4d located on the outer circumference c between surfaces 4a and 4b. The pair of side surfaces 4c extends radially. The pair of side surfaces 4d faces in a direction substantially perpendicular to the pair of side surfaces 4c. The circuit board 4 is positioned between the rotating body 3 and the stator 9 in the x-axis direction of the shaft 2 (see Figure 2).

[0036] As shown in Figure 5, a light-emitting unit 5 and a light-receiving unit 6 are provided on surface 4a of the circuit board 4. The light-emitting unit 5 and the light-receiving unit 6 are spaced apart from each other in the radial direction. Specifically, the light-emitting unit 5 is located on the outer circumference side c, and the light-receiving unit 6 is located on the inner circumference side d.

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

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

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

[0040] The edge portion 42 protrudes from the side surface 4c toward the outer circumference c. When the boss 77 of the housing 7, which will be described later, is inserted into the hole 41, the edge portion 42 comes into contact with the edge portion 78 of the housing 7.

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

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

[0043] As shown in Figure 5, the housing 7 has an upper housing 71 positioned on the upper side a in the axial x direction and covering the outer circumferential surface 3c of the rotating body 3, and a lower housing 72 positioned on the lower side b in the axial x direction and housing the stator 9.

[0044] As shown in Figure 4, the upper housing 71 has an end face 71a located on the upper side a in the axial x direction, a lower surface 71b which is disc-shaped or substantially disc-shaped with respect to the axis x and located on the lower side b of the end face 71a, and an outer peripheral surface 71c which is located between the end face 71a and the lower surface 71b and on the outer peripheral side c in the axial x direction. The outer peripheral surface 71c is located on the outer peripheral side c of the outer peripheral surface 3c of the rotating body 3.

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

[0046] As shown in Figure 5, a hole 75 is formed in the lower surface 71b of the upper housing 71 to expose the light-emitting unit 5 and the light-receiving unit 6. The hole 75 is formed so that when the circuit board 4 is fixed to the upper housing 71, the light-emitting unit 5 and the light-receiving unit 6, which are located on the surface 4a of the circuit board 4, can be inserted from the lower b to the upper a in the axial x direction. Specifically, the hole 75 penetrates from the bottom surface 73 on the rotating body side to the bottom surface 74 on the circuit board 4 side.

[0047] As shown in Figure 4, the bottom surface 74 on the circuit board 4 side has a radially extending base portion 76, a cylindrical or substantially cylindrical boss 77, 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 is formed, through which the shaft 2 is inserted.

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

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

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

[0051] The upper housing 71 and the lower housing 72 house a rotor 8 including a shaft 2 and a stator 9 surrounding the rotor 8. The housing 7 also has a bearing 81a that rotatably supports the upper a portion of the shaft 2 in the x-axis direction, and a bearing 81b that rotatably supports the lower b portion of the shaft 2 in the x-axis direction.

[0052] Bearings 81a and 81b are positioned radially inside the rotating body 3. Specifically, bearings 81a and 81b are located below the upper surface 3a of the rotating body 3, and rotate It is positioned on the inner circumference d of the protruding portion 32 of body 3.

[0053] The rotor 8 includes a shaft 2, a core 83 formed in an annular shape to surround the shaft 2, and a magnet 84 formed in an annular shape to surround the outer surface c of the core 83. The upper part a of the shaft 2 is inserted through the hole 31. A bush 82 is attached between the outer surface c of the shaft 2 and the inner surface d of the hole 31.

[0054] The stator 9 includes a stator core 91 formed in an annular shape to surround the rotor 8, a coil 92 wound around an extended portion (not shown) extending from the stator core 91 toward the inner circumference d, and an insulator (not shown) that insulates the stator core 91 and the coil 92.

[0055] [1-5. Method for detecting rotational position] Next, we will explain how to detect the rotational position of motor 1.

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

[0057] As 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, as the rotating body 3 rotates, the through hole 35 formed in the protruding portion 32 passes between the light-emitting portion 5 and the light-receiving portion 6, so the light-receiving portion 6 can receive light from the light-emitting portion 5 or not. 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 light from the light-emitting portion 5. Also, if 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, and therefore the light-receiving portion 6 cannot receive light from the light-emitting portion 5. In this way, the presence or absence of light reception occurs, and based on the timing of this reception, the rotation angle (rotation position), rotation speed, and rotational speed of the shaft 2 are detected via a control unit (not shown).

[0058] In this 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 rotational position of the shaft 2 is detected by the timing of the light received by the light-receiving portion 6 from the light-emitting portion 5. Therefore, compared to the case where the rotational position is detected by detecting the magnetic flux that changes with the rotation of the shaft 2, changes in ambient temperature do not affect the accuracy of rotational angle detection, and the rotational angle can be detected with high accuracy.

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

[0060] Furthermore, since it has claws 80a and 80b that lock onto 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 positioned horizontally in the radial direction of the rotating body 3.

[0061] Furthermore, since the circuit board 4, on which the light-emitting unit 5 and the light-receiving unit 6 are provided, is positioned between the rotating body 3 and the stator 9 in the axial x direction, it is possible to easily adjust the phase of the shaft 2 and the rotating body 3.

[0062] Furthermore, bearings 81a and 81b are positioned below the upper surface 3a of the rotating body 3 in the axial x direction (b), and on the inner circumference (d) of the protruding portion 32 of the rotating body 3. This allows for a reduction in the height of the motor 1 in the axial x direction, thereby achieving overall miniaturization.

[0063] In the first embodiment of the present invention described above, the case in which multiple through-holes 35 through which light emitted from the light-emitting unit 5 passes are formed on the outer peripheral surface 32c of the protruding unit 32 was explained, but a single through-hole 35 may be formed on the outer peripheral surface 32c. In this case, the light-receiving unit 6 can detect the rotational speed and rotational rate of the shaft 2 based on the timing of receiving light from the light-emitting unit 5.

[0064] [1-6. Variations] Next, with reference to Figure 6, a first and second modified example of the rotating body 3 of the motor 1 according to the first embodiment described above will be explained. Figure 6 is a diagram showing modified examples of the rotating body 3 of the motor 1, where Figure 6(a) is a perspective view of the rotating body 103a showing the first modified example in the motor 1, and Figure 6(b) is a perspective view of the rotating body 103b showing the second modified example in the motor 1. Hereinafter, components that are the same as or similar to those in the motor 1 according to the first embodiment described above will be denoted by the same reference numerals and their descriptions will be omitted.

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

[0066] Multiple projections 132a are arranged at equal intervals in the circumferential direction e centered on the axis x (four in this first modified example). That is, the multiple projections 132a are arranged at equal angle intervals (90 degrees in this first modified example) around the axis x.

[0067] Furthermore, the projection 132a is positioned on the lower side b in the axial x direction and has a lower portion 133a that passes between the light-emitting portion 5 and the light-receiving portion 6 (see Figure 2) as the shaft 2 rotates, and an upper portion 134a positioned on the upper side a in the axial x direction of the lower portion 133a. The lower portion 133a and the upper portion 134a are part of the projection 132a, but are actually arranged as an integrated unit.

[0068] The lower portion 133a of the protrusion 132a is the portion from the position facing the tip 5a of the light-emitting part 5 (see Figure 2) and the tip 6a of the light-receiving part 6 (see Figure 2) to the end face 130a, when the end face 130a of the protrusion 132a is positioned facing the circuit board 4. The lower portion 133a of the protrusion 132a is positioned at a predetermined distance from the light-emitting part 5 and the light-receiving part 6 (see Figure 2). When the shaft 2 rotates, the lower portion 133a of the protrusion 132a passes between the light-emitting part 5 and the light-receiving part 6 without coming into contact with them 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 of the light-emitting portion 5 (see Figure 2) and the tip 6a of the light-receiving portion 6 (see Figure 2) to the surface 3b of the rotating body 103a, when the end face 130a of the protruding portion 132a is positioned facing the circuit board 4.

[0070] As the rotating body 103a rotates in conjunction with the rotation of the shaft 2, the lower portion 133a of the protruding part 132a passes between the light-emitting part 5 and the light-receiving part 6 (see Figure 2) without contacting them. At this time, the light-receiving part 6 determines whether or not it receives light from the light-emitting part 5. That is, when the protruding part 132a does not pass between the light-emitting part 5 and the light-receiving part 6, the light-receiving part 6 receives light from the light-emitting part 5. Also, when the lower portion 133a of the protruding part 132a passes between the light-emitting part 5 and the light-receiving part 6, the light from the light-emitting part 5 is blocked, and therefore the light-receiving part 6 cannot receive light from the light-emitting part 5. In this way, the presence or absence of light reception occurs, and depending on the timing of this reception, the rotation angle (°) of the shaft 2 is controlled via a control unit (not shown) or the like. The rotation position, rotation speed, and rotational velocity are detected.

[0071] In the first modification described above, the case in which multiple protrusions 132a are arranged on the rotating body 103a was explained, but the case in which only one protrusion 132a is arranged on the rotating body 103a is also possible. Furthermore, although the case in which the protrusion 132a is cylindrical was explained, it may also be rectangular prism, triangular prism, cylindrical, etc.

[0072] As shown in Figure 6(b), the rotating body 103b has a projection 132b that protrudes toward the circuit board 4 (see Figure 2) from the surface 3b facing the surface 4a of the circuit board 4. The shape of the projection 132b is cylindrical with axis x as its center. This projection 132b is located on the inner side d of the inner surface 3d of the rotating body 3.

[0073] The protruding portion 132b has a notch 135b formed by cutting out from the end face 130b toward the face 3b. Multiple notches 135b are formed at equal intervals around the axis x (four in this first modified example).

[0074] Furthermore, the protrusion 132b is positioned on the lower side b in the axial x direction and has a lower portion 133b that passes between the light-emitting portion 5 and the light-receiving portion 6 (see Figure 2) as the shaft 2 rotates, and an upper portion 134b positioned on the upper side a in the axial x direction of the lower portion 133b. The lower portion 133b and the upper portion 134b are part of the protrusion 132b, but are actually arranged as an integrated unit.

[0075] The lower portion 133b of the protrusion 132b is the portion from the position facing the tip 5a of the light-emitting part 5 (see Figure 2) and the tip 6a of the light-receiving part 6 (see Figure 2) to the end face 130b, when the end face 130b of the protrusion 132b is positioned facing the circuit board 4. The lower portion 133b of the protrusion 132b is positioned at a predetermined distance from the light-emitting part 5 and the light-receiving part 6 (see Figure 2). When the shaft 2 rotates, the lower portion 133b of the protrusion 132b passes between the light-emitting part 5 and the light-receiving part 6 without coming into contact with them 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 of the light-emitting portion 5 (see Figure 2) and the tip 6a of the light-receiving portion 6 (see Figure 2) to the surface 3b of the rotating body 103b, when the end face 130b of the protruding portion 132b is positioned facing the circuit board 4.

[0077] As the rotating body 103b rotates along with the rotation of the shaft 2, the lower portion 133b of the protrusion 132b passes between the light-emitting portion 5 (see Figure 2) and the light-receiving portion 6 (see Figure 2) without contacting them. At this time, as the rotating body 103b rotates, the notch 135b formed in the protrusion 132b passes between the light-emitting portion 5 and the light-receiving portion 6, so the light-receiving portion 6 can either receive light from the light-emitting portion 5 or not. 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 light from the light-emitting portion 5. Also, if the portion of the lower portion 133b of the protrusion 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, and therefore the light-receiving portion 6 cannot receive light from the light-emitting portion 5. In this way, the presence or absence of light reception is determined, and based on the timing of the light reception, the rotation angle (rotation position), rotation speed, and rotational velocity of shaft 2 are detected via a control unit (not shown).

[0078] In the second modification described above, the case in which multiple notches 135b are formed in the protruding portion 132b was explained, but it is also possible for only one notch 135b to be formed in the protruding portion 132b.

[0079] [2. Second Embodiment] Next, the configuration of the motor according to the second embodiment of the present invention will be described with reference to Figures 7 and 8. Figure 7 is a schematic perspective view showing the configuration of the rotating body 203 of the motor according to the second embodiment of the present invention. Figure 8 is a schematic perspective view showing the configuration of the circuit board 4 and housing 207 of the motor according to the second embodiment of the present invention. Hereinafter, components that are the same as or similar to the motor 1 according to the first embodiment described above will be denoted by the same reference numerals and their descriptions will be omitted.

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

[0081] The projection 232 is positioned on the lower side b in the axial x direction and has a cylindrical lower portion 233 that passes through the inner circumference d of the light-emitting portion 205 and light-receiving portion 206 (see Figure 8), which will be described later, as the shaft 2 rotates, and a cylindrical upper portion 234 positioned on the upper side a of the lower portion 233. The lower portion 233 and the upper portion 234 are part of the projection 232, but are actually arranged as a single unit.

[0082] The lower portion 233 of the protrusion 232 is the portion from the position facing the tip 205a of the light-emitting portion 205 (see Figure 8) and the tip 206a of the light-receiving portion 206 (see Figure 8) to the end face 230, when the end face 230 of the protrusion 232 is positioned facing the circuit board 4. The lower portion 233 of the protrusion 232 is positioned at a predetermined distance from the light-emitting portion 205 and the light-receiving portion 206. When the shaft 2 rotates, the lower portion 233 of the protrusion 232 rotates along the inner circumference d of the light-emitting portion 205 and the light-receiving portion 206 without contacting them as the shaft 2 rotates.

[0083] The upper portion 234 of the protrusion 232 is the portion from the point where the tip 205a of the light-emitting portion 205 (see Figure 8) and the tip 206a of the light-receiving portion 6 (see Figure 8) face each other, to the surface 3b of the rotating body 3, when the end face 230 of the protrusion 232 is positioned facing the circuit board 4.

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

[0085] As shown in Figure 8, a light-emitting unit 205 and a light-receiving unit 206 are provided on surface 4a of the circuit board 4 (see Figure 2). The light-emitting unit 205 and the light-receiving unit 206 are arranged radially, facing the outer peripheral surface 32c of the protruding portion 232.

[0086] The housing 207 includes an upper housing 271 positioned on the upper side a in the axial x direction and covering the outer circumferential surface 3c of the rotating body 203, and a lower housing 72 positioned on the lower side b in the axial x direction and housing the stator 9 (see Figure 2).

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

[0088] The lower surface 271b of the upper housing 271 has a hole 275 that exposes the light-emitting part 205 and the light-receiving part 206. The hole 275 allows the circuit board 4 (see Figure 4) to pass through the upper housing 2 When fixed to 71, the light-emitting part 205 and the light-receiving part 206, which are positioned on the surface 4a of the circuit board 4, are formed to be insertable from the lower side b to the upper side a in the axial x direction. 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] As the rotating body 203 rotates, the lower portion 233 of the protrusion 232 rotates around the inner circumference d of the light-emitting portion 205 and the light-receiving portion 206 without contacting them. In this case, as the rotating body 203 rotates, the reflective surface of the protrusion 232 passes around the inner circumference d of the light-emitting portion 205 and the light-receiving portion 206, so the light-receiving portion 206 can either receive light from the light-emitting portion 205 or not. That is, when the reflective surface 235 faces the light-emitting portion 205 and the light-receiving portion 206, the light-receiving portion 206 receives light from the light-emitting portion 205. Also, if any part of the lower portion 233 of the protrusion 232 other than the reflective surface 235 faces the light-emitting portion 205 and the light-receiving portion 206, the light-receiving portion 206 cannot receive light from the light-emitting portion 205. In this way, the presence or absence of light reception is determined, and based on the timing of the light reception, the rotation angle (rotation position), rotation speed, and rotational velocity of shaft 2 are detected via a control unit (not shown).

[0090] In this motor 1, the protruding portion 232 of the rotating body 203 passes through the inner circumference d of the light-emitting portion 205 and the light-receiving portion 206, and the rotational position of the shaft 2 (see Figure 2) is detected by the timing of the light reception from the light-emitting portion 205 received by the light-receiving portion 206. Therefore, compared to the case where the rotational position is detected by detecting the magnetic flux that changes with the rotation of the shaft 2, changes in ambient temperature do not affect the accuracy of the rotational angle detection, and the rotational angle can be detected with high accuracy.

[0091] In the second embodiment described above, the case in which multiple reflective surfaces 235 are arranged on the outer peripheral surface 32c of the protruding portion 232 was explained, but the reflective surface 235 may be arranged as a single surface on the outer peripheral surface 32cc of the protruding portion 232. Also, the outer peripheral surface 32c of the protruding portion 232 may be a reflective surface and may have a non-reflective surface that does not reflect light from the light-emitting portion 205 to the light-receiving portion 206.

[0092] Although embodiments of the present invention have been described above, the present invention is not limited to the motor 1 according to the above embodiments, but includes all aspects included in the concept and claims of the present invention. Furthermore, each component may be selectively combined as appropriate to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately changed depending on the specific use of the present invention.

[0093] Furthermore, the shape of the rotating body 3,203 according to the first and second embodiments of the present invention can be appropriately modified as long as the protruding portions 32,232 of the rotating body 3,203 face the light-emitting portion 5,205 and the light-receiving portion 6,206, resulting in the presence or absence of light reception from the light-emitting portion 205 to the light-receiving portion 206. [Explanation of Symbols]

[0094] 1…Motor, 2…Shaft, 2a,2b…End, 3…Rotating body, 3a…Top surface, 3b…Surface, 3c…Outer circumference, 3d…Inner circumference, 3e…End face, 4…Circuit board, 4a…Surface on the rotating body side, 4b…Surface on the stator side, 4c,4d…Side, 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…Cylinder part, 31…Hole part, 32… Protruding part, 32a...end face, 32c...outer surface, 32d...inner surface, 33...lower part, 34...upper part, 35...through hole, 36...boundary, 41...hole, 42...edge, 43...hole, 71...upper housing, 71a...end face, 71b...bottom surface, 71c...outer 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, 79...hole, 79 h... Through hole, 80a, 80b... Claws, 81a, 81b... Bearings, 82... Bushings, 83... Core, 84... Magnet, 91... Stator core, 92... Coil, 103a... Rotating body, 103b... Rotating body, 130a... End face, 130b... End face, 132a... Protrusion, 132b... Protrusion, 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...protrusion, 233...lower part, 234...upper part, 235...reflective surface, 236...boundary, 271...upper housing, 271b...bottom 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 circumference side, d...inner circumference side, e...circumferential direction

Claims

1. The shaft and A rotating body supported by the aforementioned shaft, A housing for accommodating the rotating body, In the longitudinal direction of the shaft, a circuit board facing the rotating body and, A stator having a coil, A light-emitting part provided on the rotating body side of the circuit board, A light receiving unit provided on the rotating body side of the circuit board, It includes a control unit, The housing comprises an annular end face in the longitudinal direction of the shaft and an outer circumferential surface forming the end face, The light-emitting unit and the light-receiving unit are separated from each other. In the longitudinal direction of the shaft, the circuit board is located between the stator and the rotating body. The outer circumferential surface of the housing surrounds the rotating body, The rotating body comprises a surface facing the circuit board, a projection provided on the surface facing the circuit board in the longitudinal direction of the shaft, and a cylindrical portion surrounding the projection. The protruding portion passes between the light-emitting portion and the light-receiving portion as the shaft rotates. The rotation angle, rotational speed, or rotational velocity of the shaft is detected at the timing when the light receiving unit receives light from the light emitting unit. A motor in which the phase of the shaft and the phase of the rotating body are adjusted in the circumferential direction.

2. The motor according to claim 1, wherein the light-emitting unit and the light-receiving unit are provided on the side of the circuit board facing the rotating body.

3. The shape of the aforementioned protrusion is cylindrical. The motor according to claim 1, wherein a through hole is formed on the outer circumferential surface of the protruding portion.

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

5. The motor according to claim 1, wherein the shape of the protruding portion is cylindrical.

6. The motor according to any one of claims 1 to 5, comprising a rotor supported on the shaft.

7. The aforementioned housing is referred to as the first housing, The invention comprises a second housing connected to the first housing, The motor according to any one of claims 1 to 6, wherein the second housing accommodates the stator.

8. A rotating body having a cylindrical portion and a cylindrical portion located inside the cylindrical portion in the radial direction, A shaft supporting the rotating body, An optical sensor located inside the cylindrical portion, A housing having an outer surface surrounding the cylindrical portion and a bottom surface, A stator having a coil, It includes a control unit, The optical sensor comprises a light-emitting unit and a light-receiving unit. The outer circumferential surface of the housing forms an annular end face in the longitudinal direction of the shaft, The cylindrical portion passes between the light-emitting part and the light-receiving part as the shaft rotates. The cylindrical portion blocks the light from the light-emitting portion, resulting in the presence or absence of light reception at the light-receiving portion. The rotation angle, rotational speed, or rotational velocity of the shaft is detected based on the timing at which the optical sensor receives light. A motor in which the phase of the shaft and the phase of the rotating body are adjusted in the circumferential direction.

9. The motor according to claim 8, wherein a circuit board is provided between the stator and the rotating body in the longitudinal direction of the shaft.

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