JP5415751B2 - Stepping motor - Google Patents

Description

  The present invention relates to a stepping motor.

In a conventional permanent magnet (PM) stepping motor, when a yoke, a bearing, and a flange are joined together, the bearing 23 is caulked (hereinafter, caulked) to the flange 19 as shown in FIG. For this reason, the inner diameter of the yoke 18 is formed to be large so that the crimped portion 23 a does not interfere with the yoke 18. Further, as shown in FIG. 6, the flange 20 and the bearing 21 are joined so that the caulking portion 21 a of the bearing 21 is located on the side opposite to the end face of the yoke 18. Further, as disclosed in Patent Documents 1 and 2, there is a configuration in which a bearing is fixed by being press-fitted into a yoke so that a caulking portion is not generated.
Japanese Utility Model Publication No. 6-029388 JP-A-8-149784

  However, the above conventional techniques have the following problems. That is, in the case of FIG. 7, there is a gap between the bearing 23 and the yoke 18 so as to avoid the caulking portion 23 a, so that it is difficult to perform coaxial positioning even using the coaxial positioning jig 25. In the case of FIG. 6, as shown in FIG. 8, the caulking portion 21 a interferes with the end surface of the mounting member 22, and a gap G <b> 1 is generated between the end surface of the mounting member 22 and the flange 20. The position reference when attaching the outer shape of the bearing 21 to the attachment member 22 cannot be used.

  Furthermore, in the case of Patent Documents 1 and 2, the strength for fixing the bearing is insufficient due to the force applied when the bearing is press-fitted into the yoke, and the concentricity tends to go wrong.

  The present invention has been made in view of the above problems, and its object is to position the bearing without interfering with the flange and the yoke, reduce torque cross and detent torque due to deviation of the motor shaft position, and reduce vibration and noise. It is to realize a quality stepping motor.

  Another object of the present invention is to realize a high-quality stepping motor that can reduce the torque cross due to the shift of the axial position, etc., since the flange and the yoke are positioned with high accuracy coaxially by the outer shape of the bearing.

The stepping motor of the present invention that achieves the above object is provided with a yoke in which a plurality of pole teeth formed in a comb shape are alternately arranged in a circumferential direction, an exciting coil that excites the yoke, and a pole having a different outer peripheral surface. a rotor magnet which is magnetized alternately, a bearing for rotatably supporting the shaft portion of the rotor magnet, and a mounting member joined to an end face of the yoke while maintaining the bearing, Bei give a, of the yoke A notch is formed between the plurality of pole teeth by cutting out in the diameter increasing direction, and the bearing is joined to the mounting member at a plurality of locations protruding in the diameter increasing direction of the bearing. A convex portion of the bearing formed when being joined to a member is disposed in a notch between a plurality of pole teeth of the yoke, and a shaft portion of the rotor magnet is rotatably supported by the bearing. The bearing in the state As the axial direction and the axial direction of the yoke is coaxially fitted to the outer diameter of the bearing including a portion of the convex of the bearing joined to said mounting member, the inner diameter portion of the yoke .

  According to the present invention, the bearing is fixed to the flange at a plurality of locations by caulking, and the caulking portion corresponds to the notch portion between the plurality of pole teeth of the yoke, while the coaxiality between the parts depends on the outer shape of the bearing. Positioned with high accuracy. Therefore, the bearing is positioned so as not to interfere with the flange and the yoke, the torque cross and detent torque due to the deviation of the motor shaft position are reduced, and a high-quality stepping motor with less vibration and noise can be realized.

  Further, since the caulking process is not performed on the outer portion of the bearing on the output side of the motor, the bearing can be used as a position reference when the motor is attached to the attachment member.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  The following embodiments are examples as means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the apparatus to which the present invention is applied and various conditions without departing from the spirit of the present invention. The present invention is not limited to the following embodiments.

[First Embodiment]
FIG. 1 is an exploded perspective view of the stepping motor according to the first embodiment of the present invention. 2A shows a state in which the bearing 14 is crimped to a flange 13 as an attachment member, FIG. 2B shows a yoke in which a notch portion is formed between pole teeth, and FIG. 2C shows FIG. 2A. The state which attached the yoke 7 of FIG.2 (b) is each shown.

  As shown in FIG. 1, reference numeral 1 denotes a rotor magnet that is alternately magnetized as poles having different outer peripheral surfaces. 1a is a groove of a predetermined depth provided in the rotor magnet. Reference numeral 2 denotes a shaft portion made of a nonmagnetic material such as stainless steel, which is rotatably supported by the bearings 9 and 14 and on which the rotor magnet 1 is integrally mounted. Reference numeral 15 denotes a washer interposed between the output side end portion of the rotor magnet of the shaft portion 2 and the end surface of the bearing 14 in the thrust direction.

  Reference numerals 3 and 4 denote inner yokes made of a soft magnetic material in which a plurality of pole teeth 3a and 4a are alternately projected in the circumferential direction. Reference numerals 5 and 6 denote excitation coils which are mounted between the inner yokes 3 and 4 and the outer yokes 7 and 8 to excite the yokes. 7 and 8 are outer yokes made of a soft magnetic material in which a plurality of pole teeth 7a and 8a are alternately projected in the circumferential direction, and hold one end surface of the bearing 9 in the thrust direction. Reference numerals 10 and 11 denote stators composed of inner yokes 3 and 4, outer yokes 7 and 8, and exciting coils 5 and 6. Reference numeral 9 denotes a molded bearing that rotatably supports the non-output side of the shaft portion 2 and is press-fitted and fixed to the outer yoke 8. A presser plate 12 is attached to the stator 11 and supports the opposite end portion of the shaft portion 2 in the thrust direction, and covers the outer surface of the stator 11.

  Reference numeral 13 denotes a flange that is attached to the stator 10 and attaches the motor to a predetermined attachment member, and covers the outer surface of the stator 10.

  The stators 10 and 11 are joined and disposed at the joint 16 so that the inner yokes 3 and 4 are back to back in the axial direction. The outer peripheral surface of the rotor magnet 1 is disposed coaxially with the stators 10 and 11 so as to maintain a predetermined gap with the pole teeth 3a, 4a, 7a, and 8a. At this time, the groove portion 1 a of the rotor magnet 1 is disposed so as to face the joint portion 16 of the inner yokes 3 and 4.

  In the above-described configuration, when the exciting coils 5 and 6 are energized, the inner yokes 3 and 4 and the outer yokes 7 and 8 are excited and are attracted to the pole teeth 3a, 4a, 7a, and 8a. Then, torque is generated by repelling or attracting the magnetized magnetic pole of the rotor magnet 1, and the rotor magnet 1 is driven to rotate according to the energization of the exciting coils 5 and 6, and the driving force is transmitted from the shaft portion 2 to the outside. Is done. Here, the bearing 9 is press-fitted into the inner diameter of the pole teeth of the outer yoke 8 and is positioned coaxially with high accuracy with respect to the stators 10 and 11.

  Further, as shown in FIG. 2A, the outer diameter portion of the bearing 14 is press-fitted into the inner diameter portion of the flange 13 as an attachment member and positioned coaxially. Then, a plurality of portions of the outer diameter portion of the bearing 14 are deformed by caulking so as to protrude in the diameter-enlarging direction with respect to the flange 13 to form a caulking portion 14a, thereby being fixed to the inner diameter portion of the flange 13. Thereafter, the outer diameter portion of the bearing and the inner diameter portion of the yoke are fitted so that the plurality of crimped portions 14a are arranged in the notches 7b between the plurality of pole teeth 7a of the yoke 7, as shown in FIG. Combined and positioned coaxially with high accuracy.

  In addition, it is desirable that positioning holes 7 c and 13 a are formed in the outer yoke 7 and the flange 13. Thereby, by positioning both holes 7c and 13a using a positioning tool or the like, the positional relationship in the rotational direction (circumferential direction) of the outer yoke 7 and the flange 13 can be accurately positioned. At the same time, the caulking portion 14 a of the bearing 14 can be accurately positioned in the notch 7 b between the plurality of pole teeth 7 a of the yoke 7.

  However, the positioning here can be performed by using other methods such as detecting the positions of the outer yoke 7 and the flange 13 by image processing instead of the positioning holes. Further, a similar positioning hole may be formed in the outer yoke 8 and the presser plate 12 serving as a cover, and positioning may be performed in the same manner as the flange 13.

  According to the embodiment, since the outer diameter portion of the bearing 14 is press-fitted into the flange 13 and is fixed by caulking, unlike the case where only press-fitting is performed, it is possible to reduce defects such as looseness, dropout, and inclination. .

  Further, the bearing outer diameter portion and the yoke inner diameter portion are fitted and positioned so that the caulking portion 14a which is a convex portion of the bearing outer diameter portion is disposed in the notch portion 7b between the pole teeth 7a of the outer yoke 7. The coaxiality of the stators 10 and 11 with respect to the bearing 14 can be maintained with high accuracy.

  Further, since the caulking portion 14 a that is the convex of the bearing 14 is disposed in the notch 7 b between the pole teeth 7 a of the outer yoke 7, the flange 13 is brought into close contact with the end surface portion of the bearing 14 and the output side end surface portion of the outer yoke 7. Can be attached.

  Therefore, the mounting accuracy of each of the stator, the bearing, and the flange is improved, the torque cross and detent torque due to shaft misalignment are reduced, and a high-quality PM type stepping motor with less vibration and noise can be realized.

[Second Embodiment]
FIG. 4 is a cross-sectional view showing a configuration of a PM type stepping motor according to the second embodiment.

  In FIG. 4, 17 is a pressing plate which is a cover, and 23 is a bearing.

  The bearing 23 is positioned coaxially between the bearing outer diameter portion and the inner diameter portion of the presser plate 17 that is a cover, and the bearing outer diameter portion is crimped and fixed to the presser plate 17 at a plurality of locations. Then, the bearing outer diameter portion and the yoke inner diameter portion are fitted and positioned so that the plurality of crimping portions 23 a are arranged in the notches 8 b between the plurality of pole teeth of the outer yoke 8. As described above, since the plurality of crimped portions 14a and 23a of the bearings 14 and 23 can be arranged in the notches 7b and 8b between the pole teeth 7a and 8a of the outer yokes 7 and 8, the stators 10 and 11 with respect to the bearings 14 and 23 can be arranged. The coaxiality can be maintained with high accuracy.

  1 is the same as the configuration of FIG. 1 except that the opposite end portion of the shaft portion 2 is configured in the same manner as the output end portion, and the shaft portion 2 penetrates both end faces of the stators 10 and 11. The description will be omitted.

  According to the present embodiment, by providing bearings at both end portions of the shaft portion of the motor, it is possible to reduce the shaft misalignment of the bearings at both end portions of the shaft portion, reduce torque cross and detent torque, and reduce vibration and noise. A small high-quality PM-type stepping motor can be realized.

[Third Embodiment]
FIG. 5 is a cross-sectional view showing the configuration of the PM type stepping motor of the third embodiment.

  In FIG. 5, 24 is an angle which is an attachment member when attaching a motor.

  Except that the flange 13 in FIG. 2 is replaced with an angle 24, the configuration is the same as that in FIG.

  According to this embodiment, the motor is suitable for application as a drive device that drives a lens or the like by rotating a screw formed on the shaft portion 2 thereof.

1 is an exploded perspective view of a PM type stepping motor according to a first embodiment of the present invention. (A) is a state in which the bearing is crimped to the flange, (b) is a yoke in which a notch is formed between pole teeth, and (c) is a view showing a state in which the yoke of (b) is attached to (a). is there. It is sectional drawing which shows the structure of PM type | mold stepping motor of 1st Embodiment. It is sectional drawing which shows the structure of PM type stepping motor of 2nd Embodiment. It is sectional drawing which shows the structure of PM type stepping motor of 3rd Embodiment. It is sectional drawing which shows the structure of the conventional PM type stepping motor. It is sectional drawing which shows the structure of the conventional PM type stepping motor. It is sectional drawing which shows the structure of the conventional PM type stepping motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor magnet 1a Groove part 3, 4 Inner yoke 3a, 4a, 7a, 8a Pole teeth 5, 6 Excitation coil 7, 8 Outer yoke 7b, 8b Notch part 7c, 8c Positioning hole 10, 11 Stator 9, 14, 15, 21, 23 Bearings 12, 17 Presser plates 13, 19, 20 Flange 13 a Positioning holes 14 a, 21 a, 23 a Caulking part 15 Washer 16 Joint 18 Yoke 22 Motor mounting part 24 Angle 25 Coaxial positioning jig G1 Gap

Claims (5)

A yoke in which a plurality of pole teeth formed in a comb shape are alternately arranged in the circumferential direction;
An excitation coil for exciting the previous Symbol yoke,
A rotor magnet outside circumferential surface is alternately magnetized to different poles,
A bearing for rotatably supporting the shaft portion of the front SL rotor magnet,
E Bei a mounting member joined to an end face of the yoke while keeping the previous SL bearing, and
A notch portion is formed between the plurality of pole teeth of the yoke and is notched in the diameter increasing direction.
The bearing is joined to the mounting member at a plurality of locations that are convex in the diameter increasing direction of the bearing,
A convex portion of the bearing formed when joined to the mounting member is disposed in a notch portion between a plurality of pole teeth of the yoke, and a shaft portion of the rotor magnet is rotatably supported by the bearing. as the axial direction of the yoke and the axial direction of the bearing in a state in which the is coaxial, and the outer diameter of the bearing including a portion of the convex of the bearing joined to said mounting member, said yoke A stepping motor characterized by fitting an inner diameter part .   After the outer diameter portion of the bearing is press-fitted into the mounting member, the bearing is joined to the mounting member by deforming a plurality of locations of the outer diameter portion of the bearing in the diameter increasing direction. Item 5. A stepping motor according to item 1.   3. The stepping motor according to claim 1, wherein after the bearing is joined to the mounting member, an outer diameter portion of the bearing and an inner diameter portion of the yoke are fitted.   The hole which positions the said attachment member and a yoke with respect to the rotation direction of a shaft part is formed in the end surface where the said attachment member and the said yoke mutually oppose. A stepping motor according to claim 1.   5. The stepping motor according to claim 1, wherein the bearing is disposed at both end portions of the shaft portion of the rotor magnet and supports both end portions of the shaft portion. 6.

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