JP2008193798A - Stepping motor and manufacturing method of stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor which is improved in balance between magnetic fields in each phase, thereby stably and uniformly rotates a rotor, and can achieve low vibration and silence. <P>SOLUTION: The stepping motor 1 includes the rotor 10 and a stator 20 arranged in the external peripheral region of the rotor 10. The stator 20 has a stator 21 composed of an A-phase stator 21A and a B-phase stator 21B which are arranged in the direction of a rotating shaft. Each of the A-phase stator and the B-phase stator includes a pair of pole-toothed stator yokes 22, 23 which is arranged in a substantial mirror symmetry in the direction of the rotating shaft, and a bobbin 25 having a recess into which a pole tooth is accommodated. The stator yokes 22, 23 are constituted of casings composed of cylindrical external peripheral parts 22a, 23a, flanges 22b, 23b overhanging from one-side ends of the cylindrical external peripheral parts, and a plurality of pole teeth 22c, 23c protruding in the direction of the rotating shaft from internal peripheral edges of the flanges. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small two-phase PM type stepping motor used for driving a lens or an iris. In particular, the present invention relates to a stepping motor that balances the magnetic force of each phase and, as a result, has a good balance of magnetic force between phases, and a method of manufacturing such a stepping motor.

An example of the structure of a conventional two-phase PM type stepping motor will be described.
FIG. 9 is an exploded perspective view showing the structure of a conventional two-phase PM type stepping motor.
FIG. 10 is a cross-sectional view of the stepping motor of FIG.
The stepping motor 101 includes a rotor 110 and a stator 120 disposed in the outer peripheral area of the rotor 110.
The rotor 110 has a permanent magnet 111 having a plurality of N poles and S poles alternately magnetized on the outer periphery, and a rotating shaft 112. One end of the rotating shaft 112 is supported by a bearing 129 attached to one end of the stator 120 and is urged in the axial direction by a thrust spring 130.
The stator 120 includes a stator 121 having a plurality of magnetic poles facing the magnetic poles of the permanent magnet 111, and a coil 127 (not shown in FIG. 9) that magnetizes the magnetic poles of the stator 121.

  The stator 121 includes an A-phase stator 121A and a B-phase stator 121B arranged in the rotation axis direction. Each phase stator includes a yoke (stator yoke) 122 provided with pole teeth (claw pole) 123, a stator flange 126 provided with pole teeth 124, and a bobbin 125 in which a coil 127 is accommodated. The stator yoke 122 has a cylindrical yoke (casing) 122a and a flange portion 122b projecting inward from the inner peripheral edge of the same portion, and a plurality of pole teeth 123 extend in the rotational axis direction from the inner edge of the flange portion 122b. It protrudes. The central yoke 126 has a ring shape, and a plurality of pole teeth 124 project from the inner edge in the direction of the rotation axis. The pole teeth 123 and 124 are abutted from both sides in the rotation axis direction, and are arranged so as to alternately overlap at equal intervals in the circumferential direction. In each phase stator, the stator yoke 122 is disposed on the outer side in the rotation axis direction, and the stator flange 126 is disposed on the inner side in the same direction.

The coil bobbin 125 is formed with a substantially triangular recess 125a on the inner peripheral surface, and the pole teeth 123 and 124 are accommodated in the recess.
Moreover, the recessed part 125b extended in the circumferential direction is formed in the outer peripheral surface of the coil bobbin 125, and the coil 127 (refer FIG. 10) is accommodated in the recessed part 125b.

The stators 121A and 121B are arranged such that the pole teeth 123 and 124 are displaced from each other in the 1/2 pitch circumferential direction with the coil bobbin 125 sandwiched from both sides, and are fixed by welding or the like. Here, the positional relationship between the pole teeth 123 and 124 depends on the assembly accuracy.
As shown in FIG. 10, the end surface of the stator flange 126 is in contact with the inner surface of the end portion of the stator yoke 122.

  A magnetic field formed by energizing the coil 127 is strengthened by the yoke 122 and the stator flange 126. At this time, as described above, since the structure around the pole teeth 123 on the stator yoke side is different from the structure around the pole teeth 124 on the stator flange side, the structures of the magnetic paths of the two are different. That is, one pole tooth 123 is formed integrally with the stator yoke 122, but the other pole tooth 124 is configured to contact the stator yoke 122 and the stator flange 126. For this reason, it is expected that the balance of the magnetic fields in the phase will not be good, the rotation of the rotor will become non-uniform, and vibration and noise will occur.

  The end surface of the stator flange 126 is in contact with the inner surface of the end portion of the stator yoke 122. However, the amount of magnetic transmission varies depending on the degree of contact area, which affects the strength of the magnetic field of the pole teeth to be excited. Is also expected.

  The present invention has been made in view of the above-described problems, and makes it possible to improve the balance of the magnetic field in each phase, thereby improving the step density of the rotor and achieving low vibration and noise reduction. It is an object of the present invention to provide a stepping motor that can be used.

  A first stepping motor according to the present invention includes a rotor having a permanent magnet and a rotating shaft that are alternately magnetized with a plurality of N poles and S poles on the outer periphery, and a stator having a plurality of magnetic poles facing the magnetic poles of the rotor. And a stator that has a coil that magnetizes the magnetic poles of the stator and that is disposed in an outer peripheral area of the rotor, and the stator is an A-phase stator and a B-phase stator that are arranged in the direction of the rotation axis. A pair of stator yokes with pole teeth, wherein each of the A-phase stator and the B-phase stator is substantially mirror-symmetrical in the rotational axis direction, and the pole teeth A casing portion including a bobbin having a recessed portion to be accommodated, wherein the stator yoke includes a cylindrical outer peripheral portion and a flange portion projecting inwardly from one end of the outer peripheral portion, and the furan It consists of a plurality of pole teeth protruding in the direction of the rotation axis from the inner peripheral edge of the flange portion.

  In the present invention, the A stator and the B stator can also be configured in mirror symmetry.

  Furthermore, in the present invention, it is preferable that the pair of stator yokes are fixed by welding.

  According to the present invention, since the stator yoke and the bobbin constituting each phase stator are formed substantially in mirror symmetry in the rotation axis direction, the magnetic fields in the phases can be balanced. Since the A-phase stator and the B-phase stator can have the same configuration, the balance of the magnetic field between the two-phase stators can be stabilized. Further, by fixing the stator yoke by welding, the magnetic path of the stator is stabilized, and the magnetic balance of the excited pole teeth is stabilized. These are effective in reducing the vibration and noise of the motor. In particular, when a motor is used as a positioning device, positioning accuracy can be improved.

  A second stepping motor according to the present invention includes a rotor having a permanent magnet and a rotating shaft that are alternately magnetized with a plurality of N poles and S poles on the outer periphery, and a stator having a plurality of magnetic poles facing the magnetic poles of the rotor. And a stator that has a coil that magnetizes the magnetic poles of the stator and that is disposed in an outer peripheral area of the rotor, and the stator is an A-phase stator and a B-phase stator that are arranged in the direction of the rotation axis. And adjusting the position of the stator around the rotation axis so that the phase shift of the electrical angle between the A-phase stator and the B-phase stator is 90 °. The B-phase stator is fixed.

  Conventionally, due to errors in parts accuracy and assembly accuracy, the A-phase stator and the B-phase stator are not arranged at positions where the phase of the electrical angle is shifted by 90 °, which is strictly an ideal positional relationship. There was a case. According to the present invention, the A-phase stator and the B-phase stator are configured independently, and the phase shift of the electrical angle of the two-phase stator is measured before the both-phase stator is fixed. Can be reliably adjusted to be 90 °.

  In this invention, it is preferable that the said coil winds a flat coil wire.

  By forming the coil with a rectangular coil wire, the density of the coil wire in the cross section can be increased, and the line product increases. Therefore, the strength of the formed magnetic field can be increased and the torque is improved.

  A stepping motor manufacturing method according to the present invention includes a rotor having a permanent magnet and a rotating shaft, each having a plurality of N poles and S poles alternately magnetized on the outer periphery, and a stator having a plurality of magnetic poles opposed to the magnetic poles of the rotor. And a stator that has a coil that magnetizes the magnetic poles of the stator and that is disposed in an outer peripheral area of the rotor, and the stator is an A-phase stator and a B-phase stator that are arranged in the direction of the rotation axis. A stepping motor manufacturing method, wherein the A-phase stator and the B-phase stator are configured to be independently rotatable around the rotation axis, and the positions of the respective phase stators around the rotation axis are adjusted. For this purpose, a jig having the following a) to o) is used, and a) a core cylinder for positioning the A-phase stator and the B-phase stator around the rotation axis, and b) the rotor is set to be rotatable. , Each phase A pedestal on which one of the stators (fixed stator) is set immovably; c) a moving member that rotates and moves the other stator (movable stator) of the respective phase stators around the rotation axis; D) rotating means for rotating the rotor at a constant speed; e) means for measuring the current generated in each phase stator by the rotation of the rotor; and the electrical angle of each phase stator measured by the current measuring means. Both the stators are fixed after adjusting the position of the movable stator with respect to the fixed stator by the moving member so that the phase shift is 90 °.

  If the jig of the present invention is used, the phase shift of the electrical angle between the A-phase stator and the B-phase stator can be adjusted to 90 ° relatively easily.

  In the present invention, the pair of stator yokes are preferably fixed by welding.

  As is apparent from the above description, a stepping motor in which the A-phase stator and the B-phase stator are substantially mirror-symmetrical so that the magnetic fields in each phase are balanced and the magnetic field balance between the phases is good. Can be provided. With such a stepping motor, low vibration and noise reduction can be achieved, and a stepping motor that can improve feed accuracy even when used in a positioning device can be provided. Moreover, according to the manufacturing method of the stepping motor of the present invention, the phase shift of the electrical angle between the A-phase stator and the B-phase stator can be accurately set to 90 °.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view of a stepping motor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the stator of the stepping motor of FIG.
The stepping motor 1 has a rotor 10 and a stator 20 disposed in the outer peripheral area of the rotor 10.
The rotor 10 has a permanent magnet 11 in which a plurality of N poles and S poles are alternately magnetized on the outer periphery, and a rotating shaft 12. One end of the rotating shaft 12 is supported by a bearing 29 attached to one end of the stator 20 and is urged in the axial direction by a thrust spring 30.
The stator 20 includes a stator 21 having a plurality of magnetic poles facing the magnetic poles of the permanent magnet 11, and a coil 27 (not shown in FIG. 1) that magnetizes the magnetic poles of the stator 21. The stator 21 includes an A-phase stator 21A and a B-phase stator 21B arranged in the rotation axis direction.

  The A-phase stator 21A and the B-phase stator 21B have the same shape, and each phase stator has a pair of pole teeth (claw pole) yokes (stator yokes) 22 and 23 formed substantially mirror-symmetrically and pole teeth. And a bobbin 25 in which a recess is formed. The stator yokes 22 and 23 are composed of a casing portion composed of short cylindrical outer peripheral portions 22a and 23a, flange portions 22b and 23b projecting inward from one end of the outer peripheral portion, and flange portions 22b and 23b of the casing portion. It consists of a plurality of substantially triangular pole teeth 22c, 23c protruding from the periphery in the direction of the rotation axis.

  The stator yokes 22 and 23 are fixed by welding, with the end portions of the outer peripheral portions 22a and 23a of the casing portions on the opposite flange side being fitted together and combined. At this time, the pole teeth 22c and 23c of the stator yokes 22 and 23 are alternately arranged at equal intervals in the circumferential direction as clearly shown in FIG.

  As shown in FIG. 1, the bobbin 25 has a substantially mirror-symmetric outer shape in the rotation axis direction, and the casing portions (outer peripheral portions 22 a and 23 a and flange portions 22 b and 23 b) of the combined stator yokes 22 and 23. And in the space surrounded by the pole teeth 22c and 23c. On the inner peripheral surface of the bobbin 25, a substantially triangular recess 25a for accommodating the respective pole teeth 22c and 23c is formed. Further, an annular recess 25b is formed on the outer peripheral surface of the bobbin 25, and a coil 27 is disposed in the recess 25b as shown in FIG.

  The coil 27 is obtained by winding a thin wire having a flat cross-sectional shape (diameter of 100 μm or less) in the recess 25 b of the bobbin 25. By using such a flat thin wire, the line product is increased by about 10% compared to the coil, and the torque can be improved. The coil 27 is insulated from the pole teeth 22c and 23c by the bobbin 25.

In other words, each of the A-phase stator 121A and the B-phase stator 121B has a substantially mirror-symmetric structure around the joint surface of the stator yokes 22 and 23 (the pole teeth 22c and 23c and the coil bobbin recess 25a are not mirror-symmetrical). Absent).
The A-phase stator 21A and the B-phase stator 21B configured as described above are arranged such that the pole teeth 22c and 23c of each phase are shifted in the 1/2 pitch circumferential direction as shown in FIG. And fixed in the axial direction. As a result, the A-phase stator 121A and the B-phase stator 121B have a substantially mirror-symmetric structure with the joint surface of both stators as the center (the pole teeth 22c and 23c and the coil bobbin recess 25a are not mirror-symmetric).

  As described above, in this stepping motor 1, the stator yokes 22 and 23 and the bobbin 25 constituting the A-phase stator 21A and the B-phase stator 21B are substantially mirror-symmetrical in the rotational axis direction. Therefore, the structure around each pole tooth 22c, 23c can be made the same. Since the A-phase stator 21A and the B-phase stator 21B have the same configuration, the balance of the magnetic field between the two-phase stators can be stabilized.

FIG. 3 is an exploded perspective view showing a configuration of a stepping motor according to another embodiment of the present invention.
4 is a cross-sectional view of the stator of the stepping motor of FIG.
This stepping motor 1 'has substantially the same configuration as the stepping motor 1 of FIG. 1, but has the following structure added thereto.

  An intermediate plate 31 is fixed to an inner stator yoke 22 of one of the A-phase stator 21A and the B-phase stator 21B (A-phase stator 21A in this example). The intermediate plate 31 has a ring-shaped portion 31a fixed to the flange portion 22b of the stator yoke 22 and a lever 31b protruding outward from the outer periphery of the same portion. A ring-shaped intermediate plate 32 is fixed to the flange portion 22b of the inner stator yoke 22 of the other stator (B-phase stator 21B). The intermediate plates 31 and 32 are electrically welded to projections (projections) formed on the end face of the stator yoke 22, and these projections are provided so as not to interfere with the rotation of the stator described later. It is.

Each bobbin 25 is provided with a terminal block 25c. The terminal block 25 c protrudes outward from a window formed on the outer periphery of the inner stator yoke 22. Terminals 26 connected to both ends of each coil 27 are erected on the terminal block 25c.
Further, as shown in FIG. 3, a plurality of notches 23d for positioning when set on a jig to be described later are formed on the inner peripheral edge of the flange portion 23b of the stator yoke 23 outside the B-phase stator 21B. Yes. In addition, the some convex part provided in the flange part 23b is a projection for electric welding.

  At this stage, the A-phase stator 21A and the B-phase stator 21B are independent and are not fixed side by side in the axial direction. Therefore, using jigs described below, appropriate positions of the A-phase stator 21A and the B-phase stator 21B in the direction around the rotation axis are obtained.

FIG. 5 is a perspective view showing the overall configuration of the jig.
This jig 50 is for adjusting the phase difference between the electrical angles of the two-phase stators.
The jig 50 rotates a pedestal (fixed member) 51 for setting one stator (fixed stator, B-phase stator in this example) to be non-rotatable, and the other stator (movable stator, A-phase stator in this example). A rotating stage (moving member) 55 that rotates around an axis.

  A set hole 51a in which the rotor 10 of the motor 1 is rotatably set is formed substantially at the center of the pedestal 51. Around the set hole 51a of the pedestal 51, a fixed stator positioning projection 51b is formed. These protrusions 51b are fitted into fixing holes 23d formed in the flange portion 23b of the stator yoke 23 outside the B-phase stator 21B, and the B-phase stator 21B has the shaft core (of the rotor 10) of the set hole 51a. Set around the rotation axis).

  The pedestal 51 is provided with a probe 52 that connects to a terminal erected on the terminal block 25 c of each bobbin 25. The probe 52 is connected to an oscilloscope (not shown), and an alternating current due to a counter electromotive voltage flowing through each coil 25 is measured by the oscilloscope. Further, the pedestal 51 is rotatably provided with a rotating disk 59 that rotates the rotor 10. An elastic body 61 is attached to the outer periphery of the rotating disk 59, and the disk 59 is disposed so that the elastic body 61 contacts the outer periphery of the rotor 10 set in the set hole 51 a of the pedestal 51. When the rotary disk 59 rotates, the rotor 10 rotates due to friction with the elastic body 61.

  The rotary stage 55 includes a fixed portion 56 and a stage portion 57 that rotates with a dial 58 with respect to the fixed portion 56. The stage unit 57 is arranged such that the center of rotation is the axis of the set hole 51 a of the pedestal 51. A vertical groove 57 a is formed in the stage portion 57. The lever 31b of the intermediate plate 31 fixed to the stator yoke 22 of the A-phase stator 21A is engaged with the vertical groove 57a. Accordingly, when the stage portion 57 is rotated by the dial 58, the A-phase stator 21A rotates around the rotation center of the stage portion 57, that is, the axis of the set hole 51a. The fixed portion 56 and the stage portion 57 are provided with a scale 56a indicating the rotation angle (mechanical angle) of the stage portion 57 around the axis of the set hole 51a of the pedestal 51.

Next, a method for positioning the A-phase stator and the B-phase stator around the rotation axis using the jig 50 will be described.
First, a method for setting the motor 1 ′ on the jig 50 will be described.
FIG. 6 is a diagram illustrating a state in which the motor is set on the jig.
FIG. 7 is a sectional view of the set motor.
First, the rotor 10 is inserted and set in the set hole 51 a of the base 51. Next, the stator 20 is disposed in the outer peripheral area of the rotor 10, but the core cylinder 63 is fitted into the inner hole of the stator 20 in order to arrange the A-phase stator 21A and the B-phase stator 21B coaxially ( A gap is slightly opened between the core cylinder 63 and the magnet 11 so that the rotor 10 can rotate). The core cylinder 63 has a thickness of, for example, about 0.3 mm and is made of a nonmagnetic material (for example, austenitic stainless steel).

  After inserting the core cylinder 63 on the outer side of the rotor 10, the B-phase stator 21B is inserted on the outer side of the core cylinder 63, and the B-phase stator 21B is set on the pedestal 51 so as not to rotate by the notch 23d and the protrusion 51b. To do. Then, the A-phase stator 21 </ b> A is inserted outside the core tube 63 while engaging the lever 31 b with the vertical groove 57 a of the stage portion 57 of the rotary stage 55, and the end of the rotary shaft 12 is fitted to the bearing 29. As a result, as shown in FIG. 7, the A-phase stator 21A and the B-phase stator 21B are aligned in the rotational axis direction, the B-phase stator 21B is set to be non-rotatable, and the A-phase stator 21A rotates around the axis center. Set to be movable.

Next, a method for determining the positions of the A-phase stator and the B-phase stator around the rotation axis will be described.
FIG. 8 is a flowchart for explaining the positioning method.
First, in S1, the rotor 10, the A-phase stator 21A, and the B-phase stator 21B are set on the base 51 as described above.
Next, in S2, the rotating disk 59 is rotated at a constant speed, and the stator 10 is rotated. When the permanent magnet 11 of the rotor 10 rotates in this manner, the strength of the magnetic field between the magnetic poles (pole teeth) of the respective phase stators 21A and 21B around the rotor 10 and the permanent magnet 11 changes, and current flows to each coil 27. Flowing. Therefore, in S3, this current is taken out through the terminal 26 and the probe 52 and measured with an oscilloscope. In S4, the phase of the electrical angle between the alternating current waveform caused by the counter electromotive voltage measured by the coil 27 of the A phase stator 21A and the alternating current waveform caused by the counter electromotive voltage measured by the coil 27 of the B phase stator 21B is examined. . If the phase difference between the A phase and the B phase is not 90 °, the process proceeds to S5, where the rotary stage 55 is rotated to change the position around the rotation axis of the A phase stator 21A.

  At this time, the adjustment is made as follows. In the case of a 20-step stepping motor, the number of poles of each phase stator is 10, so the electrical angle is five times the mechanical angle. That is, the difference between the phase of the electrical angle of the alternating current waveform due to the counter electromotive voltage of each phase stator coil measured by the oscilloscope and the absolute value (α) of the difference from 90 ° is multiplied by 1/5. The difference in mechanical angle. Therefore, the rotary stage is rotated by α / 5 °, the A-phase stator is rotated with respect to the B-phase stator, and the phase difference between the two stators is set to 90 °. For example, when the measured phase difference is 95 °, 1 °, which is 1/5 times 5 ° which is the difference from 90 °, is the mechanical angle difference. Therefore, in the rotary stage 55, the stage portion 57 is rotated by 1 ° in a predetermined direction with the dial 58 while looking at the scale 56a.

  This operation is repeated until the phase difference between the electrical angles of the phase stators 21A and 21B reaches 90 °, and after adjusting the phase difference to 90 °, the process proceeds to S6, and the A-phase stator 21A and the B-phase stator 21B are fixed. . At this time, for example, the outer peripheral portions of the stator yokes of both stators are fixed at several locations by laser spot welding or the like. Thereafter, the stator 20 is removed from the jig 50, and in S7, the stator 20 and the rotor 10 are assembled to assemble the motor. Finally, in S8, an option (such as a mounting plate) is attached and completed.

It is a disassembled perspective view of the stepping motor which concerns on embodiment of this invention. It is sectional drawing of the stator of the stepping motor of FIG. It is a disassembled perspective view which shows the structure of the stepping motor which concerns on other embodiment of this invention. It is sectional drawing of the stator of the stepping motor of FIG. It is a perspective view which shows the whole structure of a jig | tool. It is a figure which shows the state which sets a motor to a jig | tool. It is sectional drawing of the set motor. It is a flowchart explaining the positioning method. It is a disassembled perspective view which shows the structure of the conventional 2 phase PM type | mold stepping motor. It is sectional drawing of the stepping motor of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 10 Rotor 11 Permanent magnet 12 Rotating shaft 20 Stator 21 Stator 22, 23 Stator yoke 25 Bobbin 26 Terminal 27 Coil 29 Bearing 30 Thrust spring 31 Intermediate plate 32 Intermediate plate 50 Jig 51 Base 52 Terminal 55 Rotation stage 56 Base 57 Stage part 58 Dial 59 Rotating disk 61 Elastic body 63 Core cylinder

Claims (7)

A permanent magnet having a plurality of alternating N and S poles on the outer periphery and a rotor having a rotation shaft;
A stator having a plurality of magnetic poles opposed to the magnetic poles of the rotor, a stator for magnetizing the magnetic poles of the stator, and a stator disposed in an outer peripheral area of the rotor;
With
The stator is a stepping motor composed of an A-phase stator and a B-phase stator arranged in the rotation axis direction,
Each of the A-phase stator and the B-phase stator is substantially mirror-symmetrical in the rotational axis direction, and a pair of pole-toothed stator yokes and a bobbin having a recess for receiving the pole teeth Including
The stator yoke includes a cylindrical outer peripheral portion, a casing portion including a flange portion extending inward from one end of the outer peripheral portion, and a plurality of pole teeth protruding in the rotation axis direction from the inner peripheral edge of the flange portion. Stepping motor characterized by that.   2. The stepping motor according to claim 1, wherein the A stator and the B stator are also mirror-symmetrical.   The stepping motor according to claim 1, wherein the pair of stator yokes are fixed by welding. A permanent magnet having a plurality of alternating N and S poles on the outer periphery and a rotor having a rotation shaft;
A stator having a plurality of magnetic poles opposed to the magnetic poles of the rotor, a stator for magnetizing the magnetic poles of the stator, and a stator disposed in an outer peripheral area of the rotor;
With
The stator is a stepping motor composed of an A-phase stator and a B-phase stator arranged in the rotation axis direction,
The A-phase stator and the B-phase stator are fixed after adjusting the position around the rotation axis of both stators so that the phase shift of the electrical angle between the A-phase stator and the B-phase stator is 90 °. Stepping motor characterized by that.   The stepping motor according to any one of claims 1 to 4, wherein the coil is formed by winding a rectangular coil wire. A permanent magnet having a plurality of alternating N and S poles on the outer periphery and a rotor having a rotation shaft;
A stator having a plurality of magnetic poles opposed to the magnetic poles of the rotor, a stator for magnetizing the magnetic poles of the stator, and a stator disposed in an outer peripheral area of the rotor;
With
The stator is a method for manufacturing a stepping motor including an A-phase stator and a B-phase stator arranged in the rotation axis direction,
The A-phase stator and the B-phase stator are configured to be independently rotatable around the rotation axis,
Using a jig having the following a) to o) for adjusting the position of each phase stator around the rotation axis,
A) A core cylinder that positions the A-phase stator and the B-phase stator around the rotation axis;
A) A pedestal on which the rotor is set to be rotatable and one of the stators (fixed stator) is set to be immovable.
C) A moving member that rotates and moves the other stator (movable stator) of the respective phase stators around the rotation axis;
D) rotating means for rotating the rotor at a constant speed;
E) means for measuring the current generated in each phase stator by the rotation of the rotor;
After adjusting the position of the movable stator with respect to the fixed stator by the moving member so that the phase shift of the electrical angle of each phase stator measured by the current measuring means is 90 °, both the stators are fixed. A stepping motor manufacturing method characterized by the above.   The method of manufacturing a stepping motor according to claim 6, wherein the pair of stator yokes are fixed by welding.

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