JP2019103206A - Geared motor and pointer type display device, and method for manufacturing rotor - Google Patents

Abstract

To suppress an individual difference between rotors, and suppress variations in rotation positions of an output shaft caused by the individual difference between of the rotors.SOLUTION: A geared motor 100 includes side surfaces 511 and 512 directed to a circumferential direction on an inner peripheral surface of a magnet 50, and a resin part 55 is structured so that at least a part of the side faces of the magnet 50 is exposed to the surface of a body part 56 formed on the inner peripheral side of the magnet 50. Accordingly, in manufacture of a rotor 5, the magnet 50 is positioned in the circumferential direction in a metal mold using the side faces 511 and 512 of the magnet 50, and positions in the circumferential direction of a pinion 58 provided on the resin part 55 and a magnetic pole of the magnet 50 can be aligned. Accordingly, the rotor 5 having a small individual difference between positional relationships between the teeth of the pinion 58 and the magnetic pole of the magnet 50 can be manufactured.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a geared motor and a pointer type display device for transmitting rotation of a rotor to an output shaft via a reduction gear mechanism, and a method of manufacturing a rotor.

  A pointer-type display device used for a meter or the like of an automobile includes a geared motor for transmitting rotation of a rotor to an output shaft through a reduction gear mechanism, and a pointer attached to an end of the output shaft. Patent Document 1 discloses a pointer type display device of this type. The pointer-type display device of Patent Document 1 includes a stopper mechanism that regulates the rotation of the output shaft at the origin position where the pointer points to the zero point of the display scale. The stopper mechanism restricts the movable range of the first gear by bringing the convex portion provided on the first gear, which rotates integrally with the output shaft, into contact with the convex portion on the case side.

Unexamined-Japanese-Patent No. 2016-101013

  In the geared motor used in the pointer-type display device of Patent Document 1, the rotor has a magnet fixed on the outer peripheral side of a resin-made barrel, and a pinion is formed on the resin-made barrel. In this type of rotor, since the angular positions of the magnetic poles of the magnet and the teeth of the pinion are not in a fixed positional relationship during manufacturing, the positions of the magnetic poles of the magnet and the teeth of the pinion for each individual rotor Relationship is different.

Here, the origin alignment in which the rotational position of the output shaft of the geared motor is aligned with the origin position is conventionally performed in the following procedure.
(1) First, the stator coil is excited to rotate the rotor in the first direction, and the first gear rotating integrally with the output shaft is brought into contact with the convex portion on the case side by the stopper mechanism, and the first gear is interposed. Stop the rotor and the output shaft.
(2) Thereafter, a feed operation is performed to rotate the rotor by a predetermined number of drive steps in the direction opposite to the first direction from the stop position by the stopper mechanism, and the output shaft is adjusted to the home position.

  When performing origin alignment by such an operation, if the positional relationship between the teeth of the pinion formed on the rotor and the magnetic poles of the magnet differs among the individual rotors, the first gear by the stopper mechanism in the above (1) The arrangement of the magnetic poles of the magnet when the motor stops is dispersed among the rotors. As a result, the positional relationship between the stator coils and the magnetic poles of the rotor at the stop position by the stopper mechanism also varies among the rotors. As a result, in the feeding operation of (2), the amount of rotation of the rotor varies due to the difference in the positional relationship between the stator coils and the magnetic poles of the rotor, so the rotational position of the output shaft varies. That is, when the excitation of the stator coil is turned off after the home position alignment, the rotational position of the output shaft varies among the rotors.

As described above, in the geared motor in which the positional relationship between the magnetic pole of the magnet and the teeth of the pinion is different for each individual rotor, there is a problem that the individual difference of the rotor causes a deviation from the origin position of the output shaft. For this reason, when this geared motor is used for a pointer-type display device, the position of the pointer deviates from the zero point of the display scale. For example, when the number of magnetic poles of the magnet is 8 and the number of teeth of the pinion is 8, the deviation θ of the angular position between the teeth of the pinion and the magnetic pole of the magnet is 45 ° at maximum. Therefore, when the reduction ratio of the reduction gear mechanism is N, the position of the pointer deviates by a maximum of θ / N ° from the zero point of the display scale due to the individual difference of the rotor. Therefore, accurate display can not be performed.

  In view of the above problems, an object of the present invention is to suppress the variation in the rotational position of the output shaft caused by the individual differences of the rotors.

  In order to solve the above problems, the present invention is a geared motor including a motor unit including a rotor and a stator, an output shaft, and a wheel train for transmitting the rotation of the rotor to the output shaft, the rotor And a ring-shaped magnet that rotates integrally with the resin portion, wherein the inner circumferential surface of the magnet is provided with a side surface facing in the circumferential direction, The resin portion includes a body portion disposed on the inner peripheral side of the magnet, and at least a part of the side surface is exposed to the surface of the body portion.

  According to the present invention, the inner peripheral surface of the magnet is provided with a side surface facing in the circumferential direction, and at least a part of the side surface of the magnet is exposed on the surface of the body formed on the inner peripheral side of the magnet Is configured as. Therefore, when manufacturing the rotor, using the side surface facing the circumferential direction formed on the inner circumferential surface of the magnet, when molding the resin portion, the magnet is positioned in the circumferential direction in the mold and provided in the resin portion The circumferential position of the driven pinion and the magnetic pole of the magnet can be matched. This makes it possible to manufacture a rotor with less individual differences in the positional relationship between the pinion teeth and the magnetic poles of the magnet. And, by using such a rotor, it is possible to reduce the variation in the positional relationship between the rotational position of the output shaft to which the rotation of the pinion is transmitted through the wheel train meshing with the pinion and the magnetic pole of the magnet. Therefore, the variation in the rotational position of the output shaft can be reduced.

  In the present invention, a notch is formed on the inner circumferential surface of the magnet, and the side surface is provided on the inner surface of the notch. Thus, by forming the notch, it is possible to form the side surface facing in the circumferential direction. For example, when the magnet is formed by injection molding, the notch can be formed by providing a convex portion which is an inverted shape of the notch on a center pin disposed in a mold. Therefore, in the mold used for molding the magnet, the positional relationship between the convex portion of the center pin and the magnetic field forming magnet for magnetizing the magnet is determined in advance, thereby predetermining the magnet relative to the magnetic pole. The notch can be formed so as to be in the specified positional relationship.

  In the present invention, the notches are formed at a plurality of places separated from each other in the circumferential direction, and the notches formed at one of the plurality of places have the side surface exposed to the surface of the body portion. . As described above, when notches are provided at a plurality of locations, the side surface of one of the locations can be used as the positioning side surface.

  In the present invention, the notches are preferably arranged at equal angular intervals. In this way, the magnet can be shaped in a well-balanced manner in the circumferential direction.

  In the present invention, it is preferable that at least one of the notches formed at the plurality of locations is a rotation prevention portion that regulates rotation of the magnet in the circumferential direction. In this way, the magnet can be positioned in the circumferential direction. Note that the rotation prevention portion may be a notch having a side surface for positioning, or may be another notch.

  In the present invention, it is preferable that the magnet is a molded article and has a gate mark formed at an angular position different from that of the notch. In this way, the molding material can be well distributed in the cavity. Therefore, the molding quality can be improved.

  In the present invention, the body portion is connected to connect a shaft portion on which the pinion is formed, an annular portion covering an inner peripheral surface of the magnet on an outer peripheral side of the shaft portion, the shaft portion and the annular portion. It is preferable that the inner side surface of the annular portion be recessed radially outward at a portion corresponding to the side surface. In this case, the convex portion of the mold can be fitted into the notch of the magnet, and the magnet can be positioned in the circumferential direction in the mold.

  In the present invention, the magnet may have a configuration in which four S poles and N poles are provided. Further, a configuration in which the number of teeth of the pinion is eight can be adopted. In this case, since the number of teeth of the pinion and the number of poles of the magnetic poles coincide with each other, all the magnetic poles and the teeth of the pinion can be arranged in the same positional relationship all around the rotor.

  Next, according to the present invention, there is provided a pointer type display device using the above geared motor, wherein the pointer is driven by the output shaft in such a pointer type display device. In the geared motor described above, the variation in the positional relationship between the rotational position of the output shaft to which the rotation of the pinion is transmitted through the gear train meshing with the pinion and the magnetic pole of the magnet can be reduced. Can be reduced. Therefore, in the pointer type display device provided with such a geared motor, it is possible to reduce the variation in the rotational position of the pointer driven by the output shaft. For example, it is possible to reduce the variation in the rotational position of the pointer when the excitation of the stator coil is turned off after the home position alignment.

  Further, the present invention is a method of manufacturing a rotor including a resin portion in which a pinion is formed and an annular magnet that rotates integrally with the resin portion, wherein the annular magnet is provided on the outer peripheral side of a center pin. The molding cavity is filled with a molding material to mold the magnet having a notch formed on the inner circumferential surface, and the magnet is magnetized by the magnetic field forming magnet disposed on the outer peripheral side of the magnet molding cavity In the first step, the contact surface on the mold side is brought into contact with the side surface facing the circumferential direction provided in the notch, and the magnet is positioned in the circumferential direction inside the resin portion forming cavity, and the resin And filling the resin in the cavity for molding the part to mold the resin part provided with the pinion, and the second step of integrating the resin part and the magnet. In the first step, the magnet is formed with a predetermined positional relationship between the magnet for forming a magnetic field and a convex portion corresponding to the notch in the center pin, and in the second step, the teeth of the pinion are And forming the resin portion with a predetermined positional relationship between the mold part and the mold part.

  According to the present invention, when manufacturing a magnet, an individual difference is not generated in the positional relationship between the magnetic pole of the magnet and the positioning side surface (side surface facing in the circumferential direction) provided on the inner peripheral surface of the magnet be able to. Further, when forming the resin portion by insert formation, the position of the tooth tip of the pinion is determined with reference to the positioning side surface (side surface facing in the circumferential direction) provided on the inner circumferential surface of the magnet. It can be configured such that individual differences do not occur in the positional relationship with the magnetic poles of the magnet. Therefore, it is possible to manufacture a rotor with less individual differences in the positional relationship between the pinion teeth and the magnetic pole of the magnet.

According to the present invention, in manufacturing the rotor, using the side surface facing the circumferential direction formed on the inner circumferential surface of the magnet, when molding the resin portion, the magnet is positioned in the circumferential direction in the mold; The circumferential position of the pinion provided in the resin portion and the magnetic pole of the magnet can be matched. This makes it possible to manufacture a rotor with less individual differences in the positional relationship between the pinion teeth and the magnetic poles of the magnet. And, by using such a rotor, it is possible to reduce the variation in the positional relationship between the rotational position of the output shaft to which the rotation of the pinion is transmitted through the wheel train meshing with the pinion and the magnetic pole of the magnet. Therefore, the variation in the rotational position of the output shaft can be reduced.

It is explanatory drawing of the geared motor to which this invention is applied. It is sectional drawing of the geared motor of FIG. It is a top view of the geared motor which removed the 2nd case. It is a top view of a 1st case, a stator core, and a rotor. It is a perspective view of a rotor. It is sectional drawing and a cross-sectional perspective view of a rotor. It is an explanatory view showing a top view of a magnet and arrangement of a magnetic pole of a rotor and a tooth tip of a pinion. It is explanatory drawing of the metal mold | die used for injection molding of a magnet. It is explanatory drawing of the origin alignment of the output shaft in the geared motor of FIG. It is explanatory drawing which shows arrangement | positioning of the magnetic pole in the rotor of a comparative example, and the tooth tip of a pinion. It is explanatory drawing of the origin alignment of the output shaft in the geared motor provided with the rotor of a comparative example.

  A geared motor and a pointer type display device to which the present invention is applied will be described below with reference to the drawings. In this specification, of the one side and the other side of the direction in which the axis L of the output shaft 10 of the geared motor 100 extends, the side from which the output shaft 10 protrudes from the case 2 of the geared motor 100 is taken as the output side L1. The side opposite to the side where the output shaft 10 protrudes is described as the non-output side L2. The axis L5 of the rotor 5 and the axis L0 of the first gear 41 of the gear train 4 are parallel to the axis L of the output shaft 10. Therefore, also about axis L0, L5, one side is made into output side L1, and the other side is explained as non-output side L2. Further, in the present specification, with regard to the rotational direction about the axis L, L0, L5, the clockwise direction and the counterclockwise direction when viewed from the counter-output side L2 are respectively clockwise and counterclockwise. The direction is CCW.

(Pointer type display device)
FIG. 1 is a perspective view of a geared motor 100 to which the present invention is applied, and FIG. 2 is a cross-sectional view of the geared motor 100 of FIG. 1 (a cross-sectional view cut at the AA position in FIG. 1A). FIG. 3 is a perspective view of the geared motor 100 with the second case 22 removed. The geared motor 100 of this embodiment is used for a pointer type display device 200 (see FIG. 2). The pointer-type display device 200 includes a geared motor 100 and a pointer 11 driven by the geared motor 100.

(Geared motor)
The geared motor 100 includes a motor unit 1, a case 2 accommodating the motor unit 1, a gear train 4 to which the rotation of the motor unit 1 is transmitted, and an output shaft 10 to which the rotation of the gear train 4 is transmitted. As shown in FIG. 2, a pointer 11 is connected to the tip of the output shaft 10. The motor unit 1 is a stepping motor having a rotor 5 rotatably supported by the case 2 and a stator 6 disposed around the rotor 5.

  The case 2 includes a first case 21 disposed on the output side L1 and a second case 22 disposed on the non-output side L2. The first case 21 includes an end plate portion 212 to which the rotor 5 and the stator 6 are assembled, and a side plate portion 211 which rises from the outer peripheral edge of the end plate portion 212 to the non-output side L2. The end plate portion 212 is formed with a cylindrical portion 213 for supporting the output shaft 10. The output shaft 10 protrudes from the cylindrical portion 213 to the output side L1.

The second case 22 is an end plate 22 facing the end plate 212 of the first case 21 in the direction of the axis L.
And a side plate portion 221 rising from the outer peripheral edge of the end plate portion 222 to the output side L1. The end plate portion 222 is formed with a shaft hole 223 for supporting the output shaft 10. The axial hole 223 penetrates the end plate portion 222. The output shaft 10 is rotatably supported by the cylindrical portion 213 of the first case 21 and the shaft hole 223 of the second case 22. In the side plate portion 211 of the first case 21, convex portions 219 are formed at a plurality of locations, and in the side plate portion 221 of the second case 22, hooks 229 are formed at positions corresponding to the convex portions 219 of the first case 21. ing. The first case 21 and the second case 22 are coupled by engaging the hook 229 and the protrusion 219.

  The rotor 5 is rotatably supported by a support shaft 59 assembled to the case 2. Both ends of the support shaft 59 are held by an axial hole 214 formed in the first case 21 and an axial hole 224 formed in the second case 22. The rotor 5 includes a cylindrical magnet 50 and a resin portion 55 disposed on the inner peripheral side of the magnet 50. The resin portion 55 includes a pinion 58 formed at the end of the non-output side L2. On the outer peripheral surface of the magnet 50, south poles and north poles are alternately arranged at equal angular intervals. In the present embodiment, the magnet 50 and the resin portion 55 are integrated by insert molding. The detailed configuration of the rotor 5 will be described later.

  The wheel train 4 decelerates the rotation of the rotor 5 and transmits it to the output shaft 10. The wheel train 4 includes a first gear 41 and a second gear 42. The first gear 41 includes a large diameter gear 411 that meshes with the pinion 58 of the rotor 5 and a small diameter gear 412 that meshes with the second gear 42. The output shaft 10 is fixed to the second gear 42 by press-fitting or insert molding. The first gear 41 is rotatably supported by the support shaft 49. Both ends of the support shaft 49 are held by an axial hole 216 formed in the first case 21 and an axial hole 226 formed in the second case 22.

  FIG. 4 is a plan view of the first case 21, the stator core 60, and the rotor 5. As shown in FIGS. 3 and 4, the stator 6 has a stator core 60 provided with a plurality of salient poles 61 opposed to the outer peripheral surface of the magnet 50 with a gap. In the present embodiment, the number of salient poles 61 is six. Two of the plurality of salient poles 61 are the main pole 611 around which the coil 9 is wound via the coil bobbin 7, and the other four are the complement poles 612. The two main poles 611 are disposed on the side of the first gear 41 with respect to the axis L5 of the rotor 5.

  The stator 6 has a coil bobbin 7 mounted to two main poles 611 and a coil 9 wound around the main pole 611 via the coil bobbin 7. Two terminal pins 8 are held by the coil bobbin 7. The end of the coil wire drawn from the coil 9 is connected to one end of the terminal pin 8. The other end of the terminal pin 8 is passed through a through hole 217 (see FIG. 4) formed in the end plate portion 212 of the first case 21 and protrudes from the first case 21 to the output L1 (see FIG. 2) ).

  As shown in FIG. 4, the stator core 60 has a diameter in a portion where the two main poles 611 to which the coil bobbin 7 is mounted is longer than the other four copoles 612 and the two main poles 611 are formed. A rectangular portion 62 overhanging in a substantially rectangular shape is provided outward in the direction. The main pole 611 protrudes radially inward from the outer peripheral portion of the rectangular portion 62. The rectangular portion 62 is connected by the connecting portion 63 on the side where the first gear 41 is positioned with respect to the rotor 5. One of the four copoles 612 projects from the connecting portion 63 toward the rotor 5. Further, on the side opposite to the first gear 41 with respect to the rotor 5, there is provided a connecting portion 64 that connects the other three pole poles 612.

In the geared motor 100 of the present embodiment, four pairs of S poles and N poles are formed at equal angular intervals in the magnet 50, and six salient poles 61 are formed in the stator core 60. The six salient poles 61 are arranged at irregular intervals. When the center of one main pole 611 in the circumferential direction is between the S pole and the N pole, that is, the boundary portion between the S pole and the N pole, the two main poles 611 are the periphery of the other main pole The centers of the directions are arranged at angular intervals facing the circumferential center of the south pole or the circumferential center of the north pole. Thereby, the excitation torque for rotating the rotor 5 is obtained.

(Assembly of geared motor)
When assembling the geared motor 100, first, the support shaft 49 of the first gear 41 is press-fit into the shaft hole 216 formed in the first case 21. Further, the support shaft 59 of the rotor 5 is press-fit into the shaft hole 214 formed in the first case 21. Thereafter, the stator 6 having the coil bobbin 7, the coil 9 and the terminal pin 8 attached to the stator core 60 is assembled to the first case 21. At this time, the tip of the support shaft 49 is inserted into the round hole 66 formed in the connecting portion 63 of the stator core 60. Further, a protruding portion 65 protruding outward in the radial direction from the connecting portion 64 of the stator core 60 is fitted in the notch 215 formed in the side plate portion 211 of the first case 21. Then, the stator core 60 is brought close to the end plate portion 212 of the first case 21, and the terminal pins 8 are inserted into the four through holes 217 formed in the end plate portion 212.

  After the stator 6 is assembled to the first case 21, the rotor 5 is assembled to the first case 21. After that, the output shaft 10 to which the second gear 42 is fixed is attached to the cylindrical portion 213 of the first case 21. Then, the first gear 41 is attached to the support shaft 49 such that the first gear 41, the pinion 58 and the second gear 42 mesh with each other. Finally, the second case 22 is placed over and coupled to the first case 21 to form the case 2.

(Geared motor operation)
In the geared motor 100 and the pointer type display device 200 configured as described above, when power is supplied to the coil 9 through the terminal pin 8, the rotor 5 rotates, and such rotation is transmitted to the output shaft 10 through the wheel train 4. Ru. Accordingly, the pointer 11 connected to the output shaft 10 is rotated. At this time, the angular position of the pointer 11 is switched by supplying a predetermined drive pulse to the coil 9, and the pointer 11 can be stopped after being rotated to the target position. In addition, a driving pulse for reverse rotation can be supplied to rotate the pointer 11 to another target position.

(Stopper mechanism)
The geared motor 100 is provided with a stopper mechanism 3 for restricting the rotation range of the output shaft 10 with respect to the case 2. The stopper mechanism 3 contacts the first case 21 and the second gear 42 in the circumferential direction, and regulates the rotation of the output shaft 10 via the second gear 42. As shown in FIG. 2, the second gear 42 projects from the center of the gear portion 421 to the output side L1, and a plate-like gear portion 421 is formed with a tooth portion that meshes with the small diameter gear portion 412 of the first gear 41. A body portion 422 and a shaft portion 423 which protrudes from the center of the gear portion 421 to the non-output side L2 are provided. On the other hand, as shown in FIG. 4, the end plate portion 212 of the first case 21 is formed with an annular convex portion 218 which protrudes to the non-output side L2. The annular convex portion 218 is formed coaxially with the cylindrical portion 213.

  The stopper mechanism 3 includes a stopper convex portion 31 projecting radially outward from the body portion 422 of the second gear 42, and a case side convex portion 32 projecting radially inward from the annular convex portion 218 of the first case 21. Be done. As shown in FIG. 3, the stopper convex portion 31 is disposed on the case side convex portion 32 on the counterclockwise direction CCW side as viewed from the non-output side L2. Therefore, when the rotor 5 is rotated in the clockwise direction CW, the second gear 42 rotates in the same rotational direction (clockwise direction CW) as the rotor 5, and the stopper convex portion 31 abuts on the case side convex portion 32. . Thereby, the rotation range in the clockwise direction CW of the output shaft 10 which rotates integrally with the second gear 42 is restricted via the second gear 42.

In this embodiment, when performing the origin alignment to match the rotational position of the output shaft 10 to the origin position, first, the stopper mechanism 3 stops the rotation of the output shaft 10, and from that state, the rotor 5 is rotated counterclockwise. A drive current to be rotated by the CCW is supplied to the coil 9 to rotate the output shaft 10 in a counterclockwise direction CCW by a predetermined drive step. The origin position of the output shaft 10 is a rotational position at which the pointer 11 is positioned at the zero point of the display scale (not shown). The stop position of the rotor 5 at the time of origin alignment will be described later.

(Structure of resin part and magnet)
FIG. 5 is a perspective view of the rotor 5. FIG. 5A is a perspective view seen from the non-output side L2, and FIG. 5B is a perspective view seen from the output side L1. 6 is a cross-sectional view and a cross-sectional perspective view of the rotor, and FIG. 6 (a) is a cross-sectional view taken along a plane perpendicular to the axis L5 (a cross-section taken along the line B-B in FIG. 5 (a) 6B is a cross-sectional perspective view (cross-sectional view cut at a C-C position in FIG. 6A) cut along a plane parallel to the axis L5. 7 (a) is a plan view of the magnet 50, and FIG. 7 (b) is an explanatory view showing the arrangement of the magnetic poles of the rotor 5 and the tips of the pinions.

  As shown in FIGS. 6 (a) and 7 (a), a notch 51 recessed outward in the radial direction is formed on the inner peripheral surface of the magnet 50. As shown in FIG. On the inner peripheral surface of the magnet 50, an arc-shaped rib 52 extending in the circumferential direction is formed in a portion where the notch 51 is not formed. The notches 51 are formed at a plurality of places separated from one another in the circumferential direction. In this embodiment, the notches 51 are arranged at four equal intervals, and the shapes of the four notches 51 are the same. The four notches 51 each have an inner side surface 510 configured by a side surface 511 facing one side in the circumferential direction, a side surface 512 facing the other side in the circumferential direction, and an arc surface 513 connecting the side surfaces 511 and 512 . As described above, since the four notches 51 each include the side surfaces 511 and 512 facing in the circumferential direction, the notches 51 function as rotation stoppers that restrict the rotation of the magnet 50. Further, one of the four notches 51 functions as a positioning portion 51A when positioning the magnet 50 in the mold when forming the resin portion 55 by insert molding.

  As shown in FIGS. 5B and 6A, the notch 51 serving as the positioning portion 51A has an exposed surface 53 in which a part of the inner side surface 510 is exposed to the surface of the rotor 5. The exposed surface 53 is formed by the side surfaces 511 and 512 and a part of the arc surface 513 in the direction of the axis L5. The resin portion 55 includes a body portion 56 disposed on the inner peripheral side of the magnet 50. An opening 57 is formed in the body 56, and the exposed surface 53 is exposed to the surface of the body 56 through the opening 57.

  As shown in FIG. 6 (b), the body 56 includes a shaft 561 disposed at the radial center of the rotor 5 and an annular portion 562 disposed on the outer peripheral side of the shaft 561. A pinion 58 is formed at the end of the non-output side L2 of the portion 561. The annular portion 562 covers the inner peripheral surface of the magnet 50, and the end of the non-output side L 2 is connected to the shaft portion 561 by the annular connection portion 563. As shown in FIGS. 5B and 6B, a recess 564 is formed between the shaft 561 and the annular portion 562 at the end face of the output side L1 of the trunk 56. As shown in FIGS. 5B and 6A, the recessed portion 564 is formed with radial ribs 565 extending in the radial direction between the shaft portion 561 and the annular portion 562. The radial ribs 565 are formed at a plurality of positions separated from one another in the circumferential direction. In the present embodiment, the radial ribs 565 are arranged at four equal angular intervals. As shown in FIG. 6A, the four radial ribs 565 are respectively positioned in the middle between the notches 51 adjacent in the circumferential direction.

In the resin portion 55, on the inner peripheral surface of the annular portion 562, a notch 566 recessed outward in the radial direction is formed at one position. The notches 566 are provided between the radial ribs 565 adjacent in the circumferential direction. An opening 57 is formed on the inner side surface of the notch 566. Here, the exposed surface 53 of the magnet 50 is located on the same plane as the inner side surface of the notch 566 formed in the resin portion 55. As shown in FIG. 5B, of the inner side surfaces of the notch 566, the side surfaces 567 and 568 located on one side and the other side in the circumferential direction respectively are notches of the magnet 50 used as the positioning portion 51A. It is located on the same plane as the side surfaces 511 and 512 of 51. Further, among the inner side surfaces of the notch 566, the arc surface 569 connecting the side surfaces 567 and 568 is located on the same plane as the arc surface 513 of the notch 51 of the magnet 50 used as the positioning portion 51A.

(Method of manufacturing rotor)
In the present embodiment, the opening 57 and the exposed surface 53 of the rotor 5 are placement marks of a mold component used for circumferentially positioning the magnet 50 in the mold when forming the resin portion 55 by insert molding. is there. The mold for insert molding is provided with a convex portion fitted to the positioning portion 51A, and the magnet 50 is positioned in the circumferential direction by fitting the positioning portion 51A to the convex portion on the mold side. At the time of positioning, a part of the side surfaces 511 and 512 and the arc surface 513 in the direction of the axis L5 abuts on the surface of the convex portion on the mold side (contact surface on the mold side). As a result, in the completed rotor 5, a notch 566 provided with an opening 57 in the resin portion 55 is formed as an arrangement mark of the convex portion on the mold side, and the exposed surface 53 of the magnet 50 is exposed from the opening 57. Do.

  When manufacturing the rotor 5, a first step of manufacturing the magnet 50 by injection molding and a second step of arranging the magnet 50 in a mold and molding the resin portion 55 by insert molding are performed. In the first step, the circumferential position of the positioning portion 51A is determined based on the arrangement of the magnetic poles in the magnet 50. Then, in the second step, the magnet 50 is positioned in the circumferential direction in the mold with reference to the positioning portion 51A provided on the magnet 50. That is, the rotor 5 is manufactured such that the magnetic pole of the magnet 50 and the tip of the pinion 58 have a predetermined positional relationship in the circumferential direction via the positioning portion 51A.

  FIG. 8 is an explanatory view of a mold used for injection molding of the magnet 50. As shown in FIG. The magnet 50 is a polar anisotropic magnet formed by injection molding, and therefore has good magnetic characteristics. The magnet 50 of the present embodiment is a ferrite magnet formed using strontium-based ferrite. FIG. 8 shows a plan view of a first mold 500 that constitutes a magnet injection mold. The first mold 500 is formed with an annular recess 501 that constitutes a magnet molding cavity. In the first mold 500, the magnetic field forming magnet 502 is disposed on the outer peripheral side of the annular recess 501. In the first mold 500, the same number (eight in the present embodiment) of magnetic field forming magnets 502 as the number of magnetic poles of the magnet 50 are radially arranged in a state corresponding to the arrangement of the magnetic poles in the magnet 50.

  In the first mold 500, a center pin 503 is disposed at the center of the annular recess 501. On an outer peripheral surface of the center pin 503, a convex portion 504 which is an inverted shape of the notch 51 of the magnet 50 is formed. In the present embodiment, in the center pin 503, convex portions 504 are formed at four positions at equal angular intervals. Therefore, when the magnet 50 is formed using the first mold 500 in the first step, notches 51 are formed on the inner peripheral surface of the magnet 50 and the magnet 50 is magnetized by the magnetic field forming magnet 502. , And S poles and N poles are alternately formed at four places in the circumferential direction.

  Here, the first mold 500 used in the first step is configured such that the convex portion 504 of the center pin 503 and the magnetic field forming magnet 502 have a predetermined positional relationship in the circumferential direction. Thereby, the magnet 50 has a structure in which the notch 51 and the magnetic pole (S pole and N pole) are disposed at a preset angular position. In this embodiment, since the number of magnetic poles is eight and the number of the notches 51 is four, the magnet 50 in which all the notches 51 have the same positional relationship with respect to the S pole and the N pole is manufactured. For example, in the first mold 500 shown in FIG. 8, for example, the angular position of the convex portion 504 is shifted by 22.5 ° from the angular position of every other magnetic field forming magnet 502. Therefore, in the magnet 50, the angular position of every other magnetic pole in the circumferential direction is offset by 22.5 ° from the angular position of the notch 51, and the notch 51 is at the angular position between the N pole and the S pole. The formed magnet 50 is manufactured. Note that this angular position is an example, and the notch 51 may be formed at the angular position magnetized to the N pole or the S pole, or the notch may be formed at a predetermined angular position between the N pole and the S pole 51 may be formed.

  The mold used in the first step is configured such that the gate position for injecting the molding material does not become uneven with respect to the magnetic pole position. In this embodiment, four south poles and four north poles are provided, and the number of gates is also four. The four gates are provided at equal angular intervals in the circumferential direction. Here, the gate position is arranged to be a position deviated from the notch 51 of the magnet 50. As a result, as shown to Fig.7 (a), the gate trace G1 is formed in the range which the circular arc shaped rib 52 extends in the magnet 50. As shown in FIG.

  In addition, the gate position of the first mold 500 is set so that the magnetic pole deviates also from the weld formed at the position shifted from the magnetic pole of the magnet 50 and at the middle position of the gates adjacent in the circumferential direction. For example, the gate position is set such that the magnetic pole of the magnet 50 is formed in the circumferential direction between the gate position and the weld position. In that case, the gate position is provided at a position shifted by an angle of 1⁄4 of the circumferential pitch of the magnetic field forming magnet 502 with respect to the magnetic field forming magnet 502. In the present embodiment, since the number of magnetic poles is eight, the circumferential pitch of the magnetic field forming magnet 502 is 45 °. Therefore, the gate position is set at a position deviated 11.25 ° from the angular position of the magnetic field forming magnet 502. As a result, as shown in FIG. 7A, the gate mark G1 is formed on the magnet 50 at a position shifted by 11.5 ° from the magnetic pole position (in the present embodiment, the angular position coinciding with the notch 51). .

  Next, in the second step, the magnet 50 is disposed in the resin portion molding cavity provided inside the mold (not shown), and the magnet 50 is positioned in the circumferential direction in the mold. Then, resin is filled in the resin portion molding cavity, and the pinion 58 and the body portion 56 are molded to form the resin portion 55. At this time, for positioning of the magnet 50 in the circumferential direction in the resin part molding cavity, a convex part facing the radial direction outside is provided in the mold provided with the resin part molding cavity, and this convex part is used as the magnet 50. The outer surface of the convex portion and the inner surface of the positioning portion 51A are circumferentially brought into contact with each other by fitting the positioning portion 51A.

  Here, in the mold used in the second step, the inverted shape of the pinion 58 is provided in the resin portion molding cavity. Then, the angular position of the tooth tip in the inverted shape of the pinion 58 provided in the mold and the angular position of the convex portion which is the positioning portion on the mold side for positioning the magnet 50 in the circumferential direction are circumferentially It is configured to have a predetermined positional relationship. More precisely, the angular position of the circumferentially facing side surface (abutment surface abutted against the magnet 50 in the circumferential direction) provided on the convex portion which is the positioning portion on the mold side, and the inverted tip of the pinion 58 The angular position of the lens is configured to be in a positional relationship preset in the circumferential direction.

  In the rotor 5 of this embodiment, when the pitch of the magnetic pole in the circumferential direction of the magnetic pole is Mθ, the magnetic pole of the magnet 50 inserted in the resin portion 55 and the tip of the pinion 58 formed in the resin portion 55 It is provided at a position displaced by 4 in the circumferential direction. In the present embodiment, since the number of magnetic poles is eight, the magnetic poles of the magnet 50 and the tips of the pinions 58 are configured to be angular positions deviated by 11.25 °. As described above, the angular position of the notches 51 in the magnet 50 coincides with the angular position of every other magnetic pole. Therefore, in the mold used in the second step, the angular position of the convex portion, which is the positioning portion on the mold side fitted with the positioning portion 51A, and the angular position of the tooth tip in the inverted shape of the pinion 58 are 11.5. The positions are shifted. Thereby, the rotor 5 of an arrangement | positioning as shown in FIG.7 (b) is manufactured.

(Align with origin)
FIG. 9 is an explanatory diagram of origin alignment of the output shaft 10 in the geared motor 100 of FIG. FIG. 9A shows a state in which the rotation of the rotor 5 is stopped by the stopper mechanism 3. Further, FIG. 9 (b) shows a state of being reversely rotated by one step from the stop position by the stopper mechanism 3. In the present embodiment, the magnetic pole of the magnet 50 is shifted by 1⁄4 (11.25 °) of the circumferential pitch of the magnetic pole with respect to the tooth tip of the pinion 58. Perform the origin alignment according to the following procedures (1) and (2).

(1) First, the rotor 5 is rotated in the clockwise direction CW, and as shown in FIG. 9A, the rotor 5 is rotated to a position where the stopper convex portion 31 abuts on the case side convex portion 32, The rotor 5 is stopped at a position where the rotation of the rotor 5 is restricted by the mechanism 3. At this time, the coils 9 of the stator 6 are excited such that one is an S pole and the other is an N pole, and the rotor 5 is balanced with the rotational direction force received from one coil 9 and the other coil 9. ing. When the pointer 11 is set to the zero point of the display scale in the pointer type display device 200, as shown in FIG. 9A, the output shaft 10 is at the position where the rotation of the rotor 5 is stopped by the stopper mechanism 3. Press 11 in.

(2) Next, from the state of FIG. 9A, the rotor 5 is reversely rotated by one step in the counterclockwise direction CCW. Thereby, the state of FIG. 9 (b) is formed. The drive current of the coil 9 is 90 ° out of phase with the drive current of one coil 9 and the drive current of the other coil 9. Therefore, when the phase of the drive current is advanced by one step (ie, 45 °) in the reverse rotational direction, the coils 9 are both excited to have the N pole. As a result, the rotor 5 rotates 22.5 ° in the counterclockwise direction CCW and stops. Thereby, the output shaft 10 stops at the origin position. In addition, the pointer 11 rotating with the output shaft 10 stops at a position indicating the zero point of the display scale.

(Position shift of the origin when there are individual differences in the rotor)
FIG. 10 is an explanatory view showing the arrangement of the magnetic poles and the tips of the pinions 58 in the rotor 5A of the comparative example. Hereinafter, for comparison with the present embodiment, the deviation of the origin position when there is an individual difference in the arrangement of the magnetic pole and the tooth tip of the pinion 58 will be described with reference to FIGS. 10 and 11. FIG. The rotors 5A and 5B of the comparative example shown in FIGS. 10A and 10B differ from the rotor 5 of the geared motor 100 of this embodiment in that the angular positions of the magnetic poles and the tips of the pinions 58 vary among the individual Is an example of a configuration manufactured in the case of

  In the rotor 5A shown in FIG. 10A, the angular positions of the magnetic pole and the tip of the pinion 58 coincide with each other. On the other hand, in the rotor 5A shown in FIG. 10 (b), the angular positions of the magnetic pole and the tip of the pinion 58 are shifted by 22.5 °. That is, in the rotor 5A shown in FIG. 10A, the angular position of the tooth tips of the pinion 58 is deviated 11.25 ° clockwise in the clockwise direction with respect to the rotor 5 of the present embodiment shown in FIG. . On the other hand, in the rotor 5A shown in FIG. 10B, the angular position of the tip of the pinion 58 is shifted 11.25 ° in the counterclockwise direction CCW relative to the rotor 5 of the present embodiment shown in FIG. There is.

  FIG. 11 is an explanatory view of origin alignment of the output shaft 10 in the geared motor 100A including the rotors 5A and 5B of the comparative example. 11 (a) and 11 (b) respectively rotate the rotor 5A of FIG. 10 (a) and the rotor 5B of FIG. 10 (b) in the clockwise direction CW at the stop position by the stopper mechanism 3 Indicates the stopped state. As shown in FIG. 11A, in the rotor 5A of the comparative example, in the stop position by the stopper mechanism 3, from the coil 9 excited so that one becomes the S pole and the other becomes the N pole, in the clockwise direction CW. Receives the force to rotate.

  After the pointer 11 is pressed into the output shaft 10 in the state of FIG. 11A, the rotor 5A is reversely rotated by one step in the counterclockwise direction CCW. That is, as in the case of FIG. 9B, the phase of the drive current is advanced by one step (ie, 45 °) in the reverse rotation direction, and the coils 9 are excited such that they both become N poles. Thus, the rotor 5A rotates 11.25 ° in the counterclockwise direction CCW and stops. That is, in the rotor 5A of the comparative example, the stop position of the output shaft 10 after the home position alignment is a position rotated 11.25 ° from the stop position by the stopper mechanism 3. Therefore, the stop position (origin position) is deviated 11.25 ° clockwise in the clockwise direction CW from the stop position (origin position) in the case of the present embodiment shown in FIG. 9B.

  Further, as shown in FIG. 11B, in the rotor 5B of the comparative example, the angular position of the tip of the pinion 58 with respect to the magnetic pole is shifted by 22.5 °. When advancing 135 degrees from the case of a), it will rotate to the stop position by the stopper mechanism 3. Therefore, the rotor 5B of the comparative example receives the force to rotate in the clockwise direction CW from the coil 9 excited so that both become the S pole at the stop position by the stopper mechanism 3.

  After the pointer 11 is pressed into the output shaft 10 in the state of FIG. 11B, the rotor 5B is reversely rotated by one step in the counterclockwise direction CCW. That is, as in the case of FIG. 9B, the coils 9 are excited so as to have both N poles. Thus, the rotor 5B rotates by 33.75 ° in the counterclockwise direction CCW and stops. That is, in the rotor 5B of the comparative example, the stop position of the output shaft 10 after the home position alignment is a position rotated 33.75 ° from the stop position by the stopper mechanism 3. Therefore, the stop position (origin position) is shifted 11.25 ° in the counterclockwise direction CCW from the stop position (origin position) in the case of the present embodiment shown in FIG. 9B.

  As described above, in the comparative example, the angular positions of the magnetic pole and the tooth tip of the pinion 58 are different for each individual, and as a result, the stop position (origin position) of the output shaft 10 after origin alignment shifts. It can be seen that the stop position of the pointer 11 fixed to 10 also varies.

(Main effects of this form)
As described above, in the geared motor 100 according to the present embodiment, the inner circumferential surface of the magnet 50 is provided with the side surfaces 511 and 512 facing in the circumferential direction. The resin portion 55 is configured such that at least a part of the side surfaces 511 and 512 of the magnet 50 is exposed on the surface of the body portion 56 formed on the inner peripheral side of the magnet 50. Therefore, when manufacturing the rotor 5, the magnet 50 is positioned in the circumferential direction in the mold for molding the resin portion 55 using the side surfaces 511 and 512 facing the circumferential direction formed on the inner peripheral surface of the magnet 50. Thus, the circumferential alignment of the tooth tips of the pinion 58 provided in the resin portion 55 and the magnetic poles of the magnet 50 can be performed. Thereby, the rotor 5 with few individual differences in the positional relationship between the tip of the pinion 58 and the magnetic pole of the magnet 50 can be manufactured. And, by using such a rotor 5, it is possible to reduce the variation in the positional relationship between the rotational position of the output shaft 10 to which the rotation of the pinion 58 is transmitted through the gear train 4 and the magnetic pole of the magnet 50. . Therefore, the variation in the rotational position of the output shaft 10 can be reduced.

  In the present embodiment, the magnet 50 is provided with side surfaces 511 and 512 facing one side and the other side in the circumferential direction, and both side surfaces 511 and 512 are provided in a mold for molding the resin portion 55. It is made to abut on the contact surface which turns to a peripheral direction. However, only one of the side surfaces 511 and 512 may be brought into contact with the contact surface on the mold side to position the magnet 50 in the circumferential direction.

  In the pointer-type display device 200 using the geared motor 100 of the present embodiment, the variation in the rotational position of the pointer 11 driven by the output shaft 10 can be reduced. For example, it is possible to reduce variation in the rotational position of the pointer 11 when the excitation of the coil 9 is turned off after the home position alignment.

In the method of manufacturing the rotor 5 used in the geared motor 100 of the present embodiment, when manufacturing the magnet, the magnetic pole of the magnet 50 and the positioning side surface (a side surface 511 facing the circumferential direction) provided on the inner peripheral surface of the magnet 50 It is possible to prevent an individual difference from occurring in the positional relationship with 512). Then, when forming the resin portion 55 by insert formation, the pinion 58 is formed on the basis of the positioning side surfaces (side surfaces 511 and 512 facing in the circumferential direction) provided on the inner peripheral surface of the magnet 50. It can be configured such that individual differences do not occur in the positional relationship between the magnetic pole of the magnet 50 and the magnetic pole. Accordingly, it is possible to manufacture the rotor 5 with less individual differences in the positional relationship between the teeth of the pinion 58 and the magnetic poles of the magnet 50.

  In the present embodiment, the notch 51 is formed on the inner circumferential surface of the magnet 50, and the side surfaces 511 and 512 are provided on the inner surface 510 of the notch 51. Thus, by forming the notch 51, it is possible to form the side surfaces 511 and 512 that face in the circumferential direction. For example, in the case where the magnet 50 is formed by injection molding, the notch 51 can be formed by providing the convex portion 504 which is the inverted shape of the notch on the center pin 503 disposed in the first mold 500. . Therefore, in the first mold 500 used for molding the magnet 50, the magnet 50 is defined by determining the positional relationship between the convex portion 504 of the center pin 503 and the magnetic field forming magnet 502 for magnetizing the magnet 50. On the other hand, the notch 51 can be formed to have a predetermined positional relationship with respect to the magnetic pole.

  In the present embodiment, the notches 51 of the magnet 50 are formed at a plurality of places separated from each other in the circumferential direction, and one place among them functions as the positioning portion 51A. Moreover, since the notch 51 formed in multiple places can use the one part or all part as a rotation prevention part, it can position the magnet 50 in the circumferential direction. Further, in the present embodiment, since the notches 51 are arranged at equal angular intervals, the magnet 50 can be shaped to be well-balanced in the circumferential direction. In addition, the notch 51 may be only one place which functions as the positioning part 51A, and one notch 51 can be used as a positioning part 51A and a rotation stopping part.

  The magnet 50 of this embodiment is a molded product, and the gate mark G1 obtained by injecting the molding material into the mold is formed at an angular position different from that of the notch 51. In this way, the molding material can be well spread in the cavity for magnet molding. Therefore, the molding quality of the magnet 50 can be improved.

  The resin portion 55 of the present embodiment includes a body portion 56 disposed on the inner peripheral side of the magnet 50. The body portion 56 has a shaft portion 561 on which the pinion 58 is formed, an annular portion 562 covering the inner peripheral surface of the magnet 50 on the outer peripheral side of the shaft portion 561, and a connection portion 563 connecting the shaft portion 561 and the annular portion 562 And the inner side surface of the annular portion 562 is a notch 566 in which a portion corresponding to the side surface 511, 512 for positioning in the magnet 50 is recessed radially outward. Such a notch 566 is formed as an arrangement mark of the convex portion on the side of the mold when the convex portion of the mold is fitted to the positioning portion 51A of the magnet 50 and the resin portion 55 is formed. Therefore, the magnet 50 can be positioned in the circumferential direction in the mold.

  In the present embodiment, the magnet 50 is provided with four south poles and four north poles, and the number of teeth of the pinion 58 is eight. Therefore, since the number of teeth of the pinion 58 and the number of poles of the magnetic poles coincide with each other, the magnetic poles and the teeth of the pinion 58 can be arranged in the same positional relationship all around the rotor 5.

(Modification)
In the above embodiment, the number of magnetic poles of the magnet 50 is eight, and the number of teeth of the pinion 58 is eight. However, the present invention is also applicable to a rotor having a different number of magnetic poles and teeth. For example, the number of magnetic poles of the magnet 50 may be six, and the number of teeth of the pinion 58 may be nine.

(Other embodiments)
Although the example which applied the geared motor 100 to the pointer type display apparatus 200 was given in the said embodiment, you may apply this invention to apparatuses other than the geared motor 100 for pointer type display apparatuses.

DESCRIPTION OF SYMBOLS 1 ... Motor part, 2 ... Case, 3 ... Stopper mechanism, 4 ... Train wheel, 5, 5A, 5B ... Rotor, 6 ... Stator, 7 ... Coil bobbin, 8 ... Terminal pin, 9 ... Coil, 10 ... Output shaft, 11 ... pointer, 21 ... first case, 22 ... second case, 31 ... convex portion for stopper, 32 ... convex portion on the case side, 41 ... first gear, 42 ... second gear, 49 ... support shaft, 50 ... magnet, DESCRIPTION OF SYMBOLS 51 Notch 51A Positioning part 52 Arc-shaped rib 53 Exposed surface 55 Resin part 56 Barrel 57 An opening 58 Pinion 59 Support shaft 60 Stator core 61 ... Salient pole, 62 ... rectangular section, 63 ... connecting section, 64 ... connecting section, 65 ... projecting section, 66 ... round hole, 100, 100A ... geared motor, 200 ... pointer type display device, 211 ... side plate section, 212 ... End plate portion, 213: tube portion, 214: axial hole, 215: notch , 216: axial hole, 217: through hole, 218: annular convex portion, 219: convex portion, 221: side plate portion, 222: end plate portion, 223: axial hole, 224: axial hole, 226: axial hole, 229 ... Hook 411 411 large diameter gear portion 412 small diameter gear portion 421 gear portion 422 body portion 423 shaft portion 500 first mold 501 annular concave portion 502 magnetic field forming magnet 503 ... Center pin, 504 ... convex part, 510 ... inner side surface, 511, 512 ... side surface, 513 ... arc surface, 561 ... axial part, 562 ... annular part, 563 ... connection part, 564 ... concave part, 565 ... radial rib, 566 ... Notches, 567, 568 ... Side surfaces, 569 ... Arc surface, 611 ... Main pole, 612 ... Copole, CCW ... Counterclockwise direction, CW ... Clockwise direction, G1 ... Gate mark, L ... Axis of output axis, L0 ... Axis of first gear, L5 ... B Other axes, L1 ... output side, L2 ... counter output side

Claims (11)

A geared motor comprising: a motor unit having a rotor and a stator; an output shaft; and a wheel train for transmitting the rotation of the rotor to the output shaft,
The rotor includes a resin portion in which a pinion meshing with the wheel train is formed, and an annular magnet rotating integrally with the resin portion.
A side surface facing in a circumferential direction is provided on an inner circumferential surface of the magnet,
The geared motor according to claim 1, wherein the resin portion includes a body portion disposed on an inner peripheral side of the magnet, and at least a part of the side surface is exposed on a surface of the body portion.   The geared motor according to claim 1, wherein a notch is formed on an inner circumferential surface of the magnet, and the side surface is provided on an inner side surface of the notch. The notches are formed at a plurality of places separated from each other in the circumferential direction,
The geared motor according to claim 2, wherein the notch formed at one of the plurality of locations includes the side surface exposed to the surface of the body portion.   The geared motor according to claim 3, wherein the notches are arranged at equal angular intervals.   5. The geared motor according to claim 3, wherein at least one of the notches formed at the plurality of locations is a detent portion that regulates circumferential rotation of the magnet. The magnet is a molded article,
The geared motor according to any one of claims 2 to 5, further comprising a gate mark formed at an angular position different from that of the notch. The body portion includes a shaft portion on which the pinion is formed, an annular portion covering an inner circumferential surface of the magnet on an outer peripheral side of the shaft portion, and a connection portion connecting the shaft portion and the annular portion. Equipped
The geared motor according to any one of claims 1 to 6, wherein a portion corresponding to the side surface of the inner side surface of the annular portion is recessed radially outward.   The geared motor according to any one of claims 1 to 7, wherein the magnet has four south poles and four north poles.   The geared motor according to any one of claims 1 to 8, wherein the number of teeth of the pinion is eight. A pointer type display device using a geared motor according to any one of claims 1 to 9,
A pointer type display device characterized in that a pointer is driven by the output shaft. A manufacturing method of a rotor comprising a resin portion in which a pinion is formed and an annular magnet rotating integrally with the resin portion,
An annular magnet molding cavity provided on the outer peripheral side of the center pin is filled with a molding material to mold the magnet having a notch formed on the inner peripheral surface, and is disposed on the outer peripheral side of the magnet molding cavity A first step of magnetizing the magnet by the generated magnetic field forming magnet;
The contact surface on the mold side is brought into contact with the side surface facing the circumferential direction provided in the notch, the magnet is positioned in the circumferential direction inside the resin portion forming cavity, and the resin portion molding cavity is formed. Performing a second step of filling the resin and molding the resin portion provided with the pinion, and integrating the resin portion and the magnet;
In the first step, the magnet is formed with a predetermined positional relationship between the magnet for forming a magnetic field and a convex portion corresponding to the notch in the center pin,
In the second step, the resin portion is formed in a predetermined positional relationship between the teeth of the pinion and the mold part.

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