JP2010057330A - Stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor on which a pitch between terminal pins is hardly reduced even if the stepping motor is miniaturized. <P>SOLUTION: The stepping motor 1 includes terminal pins 23A and 23B all of which are lined up in the direction of the axis L of a rotating shaft 3. Even if the diameter of an enclosure 25 is reduced by design change upon miniaturization of the stepping motor 1, the pitches between the terminal pins 23A and 23B are maintained as they are, so that work of soldering external lines to the terminal pins 23A and 23B does not become difficult. This invention is effective for the stepping motor 1 in which a change in the diameter of the enclosure 25 is greater than a change in the length of the enclosure 25 when the stepping motor is miniaturized. Hence the length of the enclosure 25 is used effectively in arranging the terminal pins 23A and 23B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PM (permanent magnet) type stepping motor used for driving a lens of a camera, driving a pickup lens of a media-related device, and the like.

  Conventionally, as a technology in such a field, there is Japanese Utility Model Publication No. 2-83681. In the stepping motor described in this publication, a rotor and a stator are accommodated in a two-divided housing, and the stator includes a coil wound around a bobbin, a terminal block fixed to the bobbin, and a yoke surrounding the rotor. It consists of. Then, four terminal pins arranged in a line in the diameter direction are fixed to the terminal block disposed in the approximate center of the housing.

Japanese Utility Model Publication 2-83681

  However, when the four terminal pins are arranged in a line in the diameter direction of the housing, the pitch between the terminal pins becomes smaller as the diameter of the motor housing is reduced, that is, as the motor is downsized. There is a problem that the soldering work between the external wiring and the terminal pin becomes difficult.

  An object of the present invention is to provide a stepping motor in which the pitch between terminal pins is not easily reduced even when the size reduction is promoted.

  The stepping motor according to the present invention includes a rotor fixed to a rotating shaft and magnetized alternately with N and S poles, and a coil provided in parallel with the rotor in the axial direction of the rotating shaft. In the stepping motor in which the pair of stators housed in the housing is disposed in the housing, all the terminal pins connected to the coils are aligned in a line in the axial direction of the rotating shaft.

  In this stepping motor, all the terminal pins are aligned in a line in the axial direction of the rotating shaft. Therefore, even when the housing diameter is reduced due to a design change, the size of the stepping motor is reduced. The pitch can be maintained, and the soldering operation between the external wiring and the terminal pins is not deteriorated. The present invention is particularly effective for a stepping motor in which the change in the diameter of the casing is larger than the change in the total length of the casing when the stepping motor is reduced in size, and the entire length of the casing is effectively utilized in arranging the terminal pins. can do.

  The terminal block to which each terminal pin is fixed is preferably provided with a terminal fixing extension that is exposed from the housing and extends in the axial direction of the rotation shaft. Such a configuration is effective when the design of the arrangement interval of the terminal pins is appropriately changed in accordance with the entire length of the housing, and is effective as a device for widening the pitch between the terminal pins.

  Further, when viewed from the rotating shaft side of the housing, the terminal pin is in two parallel planes orthogonal to a straight line extending along the terminal pin and extending through the outer peripheral surface of the housing. It is preferable that they are arranged. In the stepping motor according to the present invention, since the plurality of terminal pins are aligned in a line in the axial direction of the rotation shaft, the terminal pins extend along the terminal pins when viewed from the rotation shaft side of the housing. It is possible to arrange them in two parallel planes that are orthogonal to the straight line and extend through the outer peripheral surface of the housing. Therefore, the protrusion of the terminal pin is unlikely to get in the way in the device (for example, a small camera), and the stepping motor can be saved in space.

  According to the present invention, even if the miniaturization is promoted, the pitch between the terminal pins is hardly reduced, and the terminal pin arrangement suitable for the miniaturization of the stepping motor is enabled.

  Hereinafter, preferred embodiments of a stepping motor according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
As shown in FIGS. 1 and 2, the small stepping motor 1 has a cylindrical shape, and has an outer diameter of about 4 mm and an overall length of about 8 mm. Used for driving pickup lenses of related equipment. The stepping motor 1 has a rotor 5 made of a permanent magnet in which N poles and S poles are alternately magnetized at equal intervals in the circumferential direction on the outer periphery of the rotating shaft 3, and in the axis L direction of the rotating shaft 3, A pair of stators 7 </ b> A and 7 </ b> B are disposed before and after the rotor 5.

  The front stator 7A forms a magnetic circuit with the coil 9A and the yoke 11A that houses the coil 9A. The yoke 11A includes an outer yoke 13A and an inner yoke 15A made of iron. The outer yoke 13A and the inner yoke 15A are magnetic circuits via a sleeve 31a provided on a bearing 31 for supporting the rotation of the rotary shaft 3. Connected. The outer yoke 13A has four magnetic pole teeth 17A extending in the axial direction from the edge of the ring-shaped base portion 14A and forming a comb-tooth shape, and the inner yoke 15A extends from the edge of the ring-shaped base portion 16A. It has four magnetic pole teeth 19A that extend in the axial direction and form a comb-teeth shape.

  The coil 9A is disposed between the base portion 14A of the outer yoke 13A and the base portion 16A of the inner yoke 15A. The magnetic pole teeth 17A and the magnetic pole teeth 19A are alternately disposed on the same circumference, and the rotor 5 Surrounds almost half. In the stepping motor 1 having such a configuration, the outer diameter of the housing 25 can be reduced because the coil 9A and the rotor 5 are arranged in parallel in the direction of the axis L.

  Further, the stator 7A has a terminal unit 21A. Two terminal pins 23A are fixed to a resin terminal block 22A provided on the terminal unit 21A, and each terminal pin 23A is exposed from the coil 9A. An electric wire 9a is wound around each. The coil 9A forms an air-core coil and is held by a resin bobbin 20A formed integrally with the terminal block 22A of the terminal unit 21A. Then, current is supplied from the external power source to the coil 9A via the terminal pin 23A of the terminal unit 21A.

  Next, since the configuration of the stator 7B is the same as that of the stator 7A, the stator 7B will be briefly described. The rear stator 7B forms a magnetic circuit with the coil 9B and the yoke 11B. The yoke 11B includes an outer yoke 13B made of iron and an inner yoke 15B, and the outer yoke 13B and the inner yoke 15B are coupled in a magnetic circuit via a bearing sleeve. The outer yoke 13B has four magnetic pole teeth 17B extending in the direction of the axis L from the edge of the ring-shaped base portion 14B and forming a comb shape. Similarly, the inner yoke 15B also has four magnetic pole teeth 19B that extend in the direction of the axis L from the edge of the ring-shaped base portion and form a comb shape.

  Further, the stator 7B has a terminal unit 21B, and an electric wire 9b exposed from the coil 9B is wound around a terminal pin 23B protruding from a resin terminal block 22B provided in the terminal unit 21B. The coil 9B forms an air-core coil and is held by a resin bobbin formed integrally with the terminal block 22B of the terminal unit 21B.

  In the pair of front and rear stators 7A and 7B configured as described above, the magnetic pole teeth 17A, 19A, 17B, and 19B are arranged to face the outer peripheral surface of the rotor 5, and the magnetic pole teeth 17A of the stator 7A and the magnetic poles of the stator 7B are arranged. The teeth 17B do not coincide with each other in the direction of the axis L, and are shifted by a predetermined angle. The magnetic pole teeth 19A of the stator 7A and the magnetic pole teeth 19B of the stator 7B are also shifted by a predetermined angle. Then, by sequentially switching the direction of the current flowing through the coils 9A and 9B via the terminal pins 23A and 23B of the terminal units 21A and 21B, the rotor 5 rotates stepwise, and accordingly, the rotary shaft 3 also steps. Rotate into a shape.

  Further, the stepping motor 1 has a non-magnetic housing 25 that houses the pair of stators 7A and 7B and the rotor 5. The housing 25 is formed of a stainless material in a C-shaped cross section and has an opening 25c extending in the direction of the axis L. The reason why the opening 25c is formed in the housing 25 is to expose the terminal blocks 22A and 22B of the terminal units 21A and 21B to the outside, and to attach the terminal units 21A and 21B to the housing 25 when the stepping motor 1 is assembled. This is for facilitating insertion in the direction of the axis L from the open end portions 25a and 25b, and for positioning the terminal units 21A and 21B in the circumferential direction.

  Furthermore, as a result of forming the casing 25 in a C-shaped cross section, the casing 25 is opened at both ends in the direction of the axis L, and the base portions 14A of the outer yokes 13A and 13B are opened from the open ends 25a and 25b of the casing 25. 14B is exposed. By adopting such a case 25 that is open at both ends, the internal space of the housing 25 can be expanded in the direction of the axis L. Accordingly, even with the same size motor, the coils 9A and 9B and the rotor 5 inside the housing 25 can be enlarged in the direction of the axis L, so that the output can be increased while maintaining the size. This is extremely effective for further miniaturization of a small PM (permanent magnet) type stepping motor used for driving a lens of a camera, driving a pickup lens of a media-related device, and the like.

  Further, the coil 9A is an air-core coil, and a cylindrical bobbin 20A is inserted into the air-core part 9c of the air-core coil 9A, and the coil 9A comes into contact with the flange part 20a of the bobbin 20A. An ultra-thin insulating film F is disposed between the coil 9A and the base portion 14A of the outer yoke 13A, and the coil 9A and the bobbin 20A are fixed with an adhesive. The coil 9B is the same as the coil 9A. The bobbin is inserted into the air core part of the air core coil, and the coil 9B is in contact with the flange part of the bobbin.

  Further, the bearing 31 that rotatably supports the rotating shaft 3 has a donut-shaped flange portion 31b that protrudes in the radial direction from the sleeve 31a. The sleeve 31a includes the opening portion 14a of the base portion 14A of the outer yoke 13A and the inner side. The yoke 15A is press-fitted into the opening 16a of the base portion 16A, and the outer yoke 13A and the inner yoke 15A are electrically connected by the sleeve 31a.

  A screw gear 35 is press-fitted and fixed to the rotary shaft 3 of the stepping motor 1 configured as described above, and the tip of the screw gear 35 is held by a bearing 37 fixed to the tip of a frame 36 made of a magnetic material. Yes. An end plate 36 a on the base end side of the frame 36 is fixed to the front end portion of the housing 25 by welding. Although not shown, a preload mechanism for urging the rotating shaft 3 in the thrust direction is provided at the rear end of the housing 25.

  Further, four terminal pins 23A and 23B aligned in a line in the direction of the axis L of the rotary shaft 3 are embedded in the terminal blocks 22A and 22B exposed from the opening 25c having a C-shaped cross section. As a result of aligning all the terminal pins 23A and 23B in a line in the direction of the axis L of the rotary shaft 3, even when the diameter of the casing 25 is reduced due to a design change when the stepping motor 1 is downsized, the terminal pins 23A and 23B The pitch between 23B can be maintained, and the soldering operation between the external wiring and the terminal pins 23A and 23B is not deteriorated. Such a configuration is particularly effective when the stepping motor 1 is downsized and the change in the diameter of the case 25 is larger than the change in the overall length of the case 25. The arrangement of the terminal pins 23A and 23B is effective. The full length of the body 25 can be used effectively.

  Further, the terminal block 22A exposed from the casing 25 is integrated with the bobbin 20A and protrudes from the terminal block main body 37a, and protrudes forward from the terminal block main body 37a. A terminal fixing extension 37b extending in the L direction is provided. Similarly, the terminal block 22B exposed from the casing 25 has a terminal block main body 38a that is integrated with the bobbin 20B and protrudes from the casing 25, and protrudes rearward from the terminal block main body 38a. A terminal fixing extension 38b extending in the direction of the axis L is provided. One terminal block main body 37a and the other terminal block main body 38a abut on the center of the casing 25, and one terminal fixing extension 37b and the other terminal fixing extension 38b are substantially the entire length of the casing 25. Line up in a straight line.

  The use of such terminal fixing extensions 37b and 38b is such that when the four terminal pins 23A and 23B are aligned in a straight line in the direction of the axis L of the rotary shaft 3, the terminal pins 23A are matched to the entire length of the casing 25. , 23B is effective when the design is appropriately changed. Further, such a configuration makes it easy to bring the four terminal pins 23A and 23B toward one side and align them in a straight line in the radial direction of the housing 25. Note that the terminal fixing extension portions 37 b and 38 b may extend beyond the entire length of the housing 25 or may be shorter than the entire length of the housing 25. In this case, the four terminal pins 23A and 23B are arranged in a line on the T-plane portion S1 of the terminal blocks 22A and 22B having a T shape as viewed from the outside.

  As another modification of the first embodiment, as shown in FIG. 3, a stepping motor 40 includes a two-divided type casing 41 including a cup-shaped first casing 41 </ b> A and a second casing 41 </ b> B. In the housing 41, the above-described stators 7A and 7B and the rotor 5 are accommodated. In addition, the same code | symbol is attached | subjected to the component which is the same as that of the stepping motor 1 shown in FIG. 1, or equivalent, and the description is abbreviate | omitted.

[Second Embodiment]
As shown in FIG. 4, the stepping motor 43 according to the second embodiment has a casing 44 including a cylindrical first casing 44 </ b> A and a second casing 44 </ b> B divided into two parts in the front and rear directions. The casing 44 accommodates a stator and a rotor having the same configuration as that of the first embodiment. The terminal block 45A exposed from the housing 44 has a terminal block main body 47a that is integrated with the bobbin and protrudes from the housing 44, and protrudes forward from the terminal block main body 47a. A terminal fixing extension 47b extending in the L direction is provided. Similarly, the terminal block 45B exposed from the housing 44 has a terminal block main body 48a that is integrated with the bobbin and protrudes from the housing 25, and protrudes rearward from the terminal block main body 48a. A terminal fixing extension 48b extending in the L direction is provided.

  Then, one terminal block main body 47a and the other terminal block main body 48a abut on the center of the casing 44, and one terminal fixing extension 47b and the other terminal fixing extension 48b are substantially the entire length of the casing 44. Line up in a straight line. The use of such terminal fixing extensions 47b and 48b is such that when the four terminal pins 49A and 49B are aligned in a straight line in the direction of the axis L of the rotary shaft 3, the terminal pins 49A are matched to the entire length of the casing 25. , 49B is effective when the design is appropriately changed. Further, such a configuration makes it easy to bring the four terminal pins 49A and 49B toward one side and align them in a straight line in the radial direction of the housing 44. The terminal fixing extension portions 47 b and 48 b may extend beyond the entire length of the housing 44 or may be shorter than the total length of the housing 44. In this case, the four terminal pins 49A and 49B are arranged in a row on the I-surface portion S2 of the terminal blocks 45A and 45B having a T shape as viewed from the outside.

  As another modification of the second embodiment, as shown in FIGS. 5 and 6, small terminal blocks 51 </ b> A and 51 </ b> B are adopted for the stepping motor 50. Terminal block main bodies 52a and 53a shorter than the radius of the terminal 54, and terminal fixing extensions 52b and 53b extending over substantially the entire length of the casing 54. In this case, the four terminal pins 59A and 59B are arranged in a row on the I-plane portion S3 of the terminal blocks 51A and 51B having a T shape as viewed from the outside.

  Further, as shown in FIG. 6, when viewed from the rotating shaft 3 side of the housing 54, the terminal pins 59A and 59B are orthogonal to a straight line R extending along the terminal pins 59A and 59B and 54 are arranged in two parallel planes P1 and P2 extending through the outer peripheral surface 54a of 54. Therefore, the protrusions of the terminal pins 59A and 59B are unlikely to get in the way of the device (for example, a small camera), and the stepping motor 50 can be saved in space.

  As still another modification of the second embodiment, as shown in FIGS. 7 and 8, the stepping motor 60 has an oval casing 61, and the casing 61 has parallel flat surfaces 61 a and 61 b. Is provided. The terminal pins 62A and 62B are arranged in a line on the I-surface portion S4 of the terminal blocks 63A and 63B having a T shape when viewed from the outside, and with respect to a straight line R extending along the terminal pins 62A and 62B. They are arranged in two planes P1 and P2 that are orthogonal and extend along the flat surfaces 61a and 61b of the housing 61. Therefore, the protrusions of the terminal pins 62A and 62B are less likely to get in the way of the device (for example, a small camera), and the stepping motor 60 can be saved in space.

1 is a perspective view showing a first embodiment of a stepping motor according to the present invention. FIG. 2 is an exploded perspective view of the stepping motor shown in FIG. 1. It is a perspective view which shows the modification of 1st Embodiment. It is a perspective view which shows 2nd Embodiment of the stepping motor which concerns on this invention. It is a perspective view which shows the modification of 2nd Embodiment. It is A arrow directional view of FIG. It is a perspective view which shows the other modification of 2nd Embodiment. It is a B arrow line view of FIG.

Explanation of symbols

  1, 40, 43, 50, 60 ... Stepping motor, 3 ... Rotating shaft, 5 ... Rotor, 7A, 7B ... Stator, 9A, 9B ... Coil, 11A, 11B ... Yoke, 22A, 22B, 45A, 45B, 51A, 51B, 63A, 63B ... terminal block, 23A, 23B, 49A, 49B, 59A, 59B, 62A, 62B ... terminal pins, 25, 41, 44, 54, 61 ... housing, 37b, 38b, 47b, 48b, 52b 53b, terminal fixing extension, 54a, outer peripheral surface of the housing, L, axis, R, straight line, S1, S2, flat surface.

Claims (3)

A pair of rotors that are fixed to the rotating shaft and are alternately magnetized with N poles and S poles, and a coil that is provided in parallel with the rotor in the axial direction of the rotating shaft is housed in a yoke. In the stepping motor in which the stator is disposed in the housing,
All of the terminal pins connected to the coil are aligned in a line in the axial direction of the rotating shaft.   The terminal block to which each of the terminal pins is fixed is provided with a terminal fixing extension portion that is exposed from the housing and extends in the axial direction of the rotating shaft. Stepping motor.   When viewed from the rotating shaft side of the casing, the terminal pin is perpendicular to a straight line extending along the terminal pin and is parallel to two planes extending through the outer peripheral surface of the casing. The stepping motor according to claim 1, wherein the stepping motor is disposed inside the stepping motor.

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