JP2006271165A - Stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality stepping motor which prevents dispersion of properties or vibration and noise by eliminating the backlash among built-in parts. <P>SOLUTION: The stepping motor 100 is provided with a plurality of stators 9 (10) in its axial direction. The stators 9 (10) are equipped with bobbins 16 (17) in the shape of hollow cylinders where collars 16a and 16b (17a and 17b) having openings at their centers are made at both their ends, inner yokes 3 (4) and outer yokes 7 (8) which contact with the collars at both ends of the bobbins and also have a plurality of polar teeth 3a and 7a (4a and 8a) arranged alternately in its circumferential direction, exciting coils 5 (6) which are wound on the bobbins mounted between the inner yoke and the outer yoke, and motor frames 14 (15) which house the above inner yokes, the above outer yokes, the above bobbins, and the above exciting coils. Each bobbin is constituted so that the interval between the outer rims of the collars at both ends may be longer than the interval between the inner brims of the collars at both ends. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stepping motor including a rotor magnet that rotates in a stator.

  2. Description of the Related Art Conventionally, a stepping motor is known in which two motor frames having one end opened are combined so that the openings face each other (see, for example, Patent Document 1). A connection protrusion having a substantially trapezoidal shape is provided at an edge of one end opening of these motor frames, and the motor is abutted with the slopes of the connection protrusions forming the trapezoidal shapes of the two motor frames during assembly. It is configured to adjust internally generated play.

There is also known a stepping motor configured to install a spring in a motor frame and press an internal part from one side to remove the play of the internal part (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 5-33673 Japanese Patent Laid-Open No. 6-22532

However, the conventional stepping motor has the following drawbacks.
(1) Adjustment is required when assembling the stepping motor, causing problems such as variations in the coaxial position.
(2) A spring must be installed in the motor frame, and since a spring space is required, the torque is reduced and it is not suitable for downsizing.

  An object of the present invention is to provide a high-quality stepping motor that prevents variations in characteristics and vibration / noise by eliminating backlash between components incorporated in a motor frame.

  In order to achieve the above object, a stepping motor according to a first aspect of the present invention is provided with a hollow cylindrical bobbin having a central opening formed at both ends thereof, in contact with the flanges at both ends of the bobbin and alternately disposed in the circumferential direction. An inner yoke and an outer yoke having a plurality of pole teeth, an excitation coil wound around the bobbin mounted between the inner yoke and the outer yoke, and the inner yoke, the outer yoke, the bobbin and the excitation coil. A stator including a motor frame to be included; and a rotor magnet disposed in a coaxial relationship in the stator via a plurality of pole teeth and a predetermined gap and alternately magnetized to different poles on a peripheral surface A plurality of the stators are provided in the axial direction, and the outer peripheral distance between the flanges at both ends of the bobbin is longer than the inner peripheral distance between the flanges at both ends.

  According to the present invention, a plurality of stators are provided in the axial direction, and the outer peripheral distance between the flanges at both ends of the bobbin is longer than the inner peripheral distance between the flanges at both ends. This acts so as not to fill a gap (backlash) generated between the inner yoke and the bobbin or between the outer yoke. As a result, it is possible to eliminate backlash between components incorporated and incorporated in the motor frame, to prevent characteristic variations and vibration / noise, and to provide a high-quality stepping motor.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is an exploded perspective view of a stepping motor according to an embodiment of the present invention, and FIG. 2 is a sectional view in the axial direction of the stepping motor.

  The stepping motor 100 shown in FIGS. 1 and 2 is supported by a cylindrical rotor magnet 1 having 10 different poles alternately magnetized on its peripheral surface, and bearings 11 and 12, and the rotor magnet 1 is integrated. And a shaft 2 made of a nonmagnetic material such as stainless steel. The rotor magnet 1 is provided with a substantially annular groove 1a having a predetermined depth at the center in the axial direction.

  Further, the stepping motor 100 includes a pair of stators 9 and 10. The pair of stators 9, 10 has a storage hole that penetrates the rotor magnet 1 in the central direction thereof in the axial direction.

  The stators 9 and 10 include inner yokes 3 and 4, excitation coils 5 and 6, outer yokes 7 and 8, motor frames 14 and 15, and bobbins 16 and 17, respectively. Since the stators 9 and 10 have the same structure, the configuration of the stator 9 will be mainly described, and the corresponding configuration of the stator 10 will be described in parentheses with only numerals.

  The bobbin 16 (17) has a cylindrical body (not shown) around which the exciting coil 5 (6) is wound, and a flange 16a (17a) is provided at one end of the bobbin 16 in addition to the bobbin 16 (17). A flange 16b (17b) is formed integrally with a cylindrical body (not shown) at the end. On the outer periphery of the flange 16b (17b), a terminal portion 16c (17c) for holding a terminal, which is bent at a substantially right angle with respect to the flange 16b (17b) so as not to overlap with a cylindrical body (not shown). Have. The collar 16a (17a) will be described in detail later.

  The inner yoke 3 (4) is made of a soft magnetic material, and has a substantially annular hole at the center for passing through the rotor magnet 1, and is alternately arranged along the circumferential direction of the substantially annular shape. A plurality of (five) pole teeth 3a (4a) are provided. The inner yoke 3 includes a ring-shaped portion 3b that covers the end surface of the flange 16a (that is, abuts against the end surface), and the plurality of pole teeth 3a are bent at substantially right angles from the ring-shaped portion 3b. It is exposed so as to face the inner peripheral surface of the cylindrical body. On the other hand, the inner yoke 4 includes a ring-shaped portion 4b that covers the end surface of the flange 17b (that is, abuts against the end surface), and the plurality of pole teeth 4a are bent substantially at right angles from the ring-shaped portion 4b. It is exposed so as to face the inner peripheral surface of the cylindrical body. The inner yoke 3 (4) includes a protruding portion 3c (4c) having a rectangular cross section, and the protruding portion 3c (4c) is accommodated in the cutout opening 14a (15a) of the motor frame 14 (15).

  The outer yoke 7 (8) is also made of a soft magnetic material, like the inner yoke 3 (4), and has a substantially annular hole at the center for passing through the rotor magnet 1, and the substantially annular shape. A plurality of (five) pole teeth 7a (8a) are alternately arranged along the circumferential direction. The outer yoke 7 includes a ring-shaped portion 7b that covers the end surface of the flange 16b (that is, abuts against the end surface), and the plurality of pole teeth 7a are bent at substantially right angles from the ring-shaped portion 7b. It is exposed so as to face the inner peripheral surface of the cylindrical body. On the other hand, the inner yoke 8 includes a ring-shaped portion 8b that covers the end surface of the flange 17a (that is, abuts against the end surface), and the plurality of pole teeth 8a are bent substantially at right angles from the ring-shaped portion 8b. It is exposed so as to face the inner peripheral surface of the cylindrical body. The outer yoke 7 (8) includes a protruding portion 7c (8c) having a rectangular cross section, and the protruding portion 7c (8c) is accommodated in the cutout opening 14a (15a) of the motor frame 14 (15).

  The pole teeth 3a (4a) and the pole teeth 7a (8a) are different from each other and face each other. Further, the pole teeth 3a (4a) and the pole teeth 7a (8a) are configured such that the width of the pole teeth is gradually narrowed toward the tip direction. The number of pole teeth 3a (4a) and pole teeth 7a (8a) is not limited to five.

  The motor frame 14 (15) is formed in a hollow cylindrical shape having a cut-out opening 14a (15a), one end of which is opened, and the other end passes through the protruding portion 11a (12a) of the bearing 11 (12). A through hole 14b (15b) is provided. The motor frame 14 (15) houses the inner yoke 3 (4), the outer yoke 7 (8), and the bobbin 16 (17) inside, and covers the outer periphery of the exciting coil 5 (6). The motor frames 14 and 15 connect the open ends by a method such as adhesion or welding. At this time, the ring-shaped parts 3b and 4b abut.

  The bearing 11 (12) includes a protruding portion 11a (12a) that is press-fitted into a substantially annular hole (pole tooth inner diameter) of the outer yoke 7 (8), and rotatably supports the shaft 2. The coaxial of the stepping motor 100 is set based on the bearing 11 (12).

  The stators 9 and 10 are joined and arranged in the axial direction, and the rotor magnet 1 is arranged coaxially in the stators 9 and 10 via the pole teeth 3a, 4a, 7a and 8a and a predetermined gap. As shown in FIG. 2, the groove portion 1 a of the rotor magnet 1 is disposed so as to face the joint portion 13 of the inner yokes 3 and 4.

  In the above configuration, when the exciting coils 5 and 6 are energized, the inner yokes 3 and 4, the outer yokes 7 and 8, and the motor frames 14 and 15 are excited, and the pole teeth 3a, 4a, 7a and 8a are excited. The magnetic pole of the rotor magnet 1 repels or attracts the pole teeth 3a, 4a, 7a and 8a to generate torque. As a result, the rotor magnet 1 is rotationally driven in accordance with the energization of the exciting coils 5 and 6, and the driving force is transmitted from the shaft 2 to the outside.

  FIG. 3 is a sectional view of the bobbin 16 (17) in the axial direction.

  As shown in the figure, the flange 16a (17a) of the bobbin 16 extends outwardly from the inner periphery to the outer periphery (the direction in which the flange 16a pushes the inner yoke 3 or the direction in which the flange 17a pushes the outer yoke 8). Inclined, the width S2 between the outer peripheries of the flanges 16a and 16b (17a and 17b) is longer than the width S1 between the inner peripheries of the flanges 16a and 16b (17a and 17b). .

  This configuration acts so as to eliminate a gap (backlash) generated between the inner yoke 3 (4) and the bobbin 16 (17) or between the outer yoke 7 (8) and the bobbin 16 (17).

  As a result, it is possible to eliminate backlash between components incorporated and incorporated in the motor frame, to prevent characteristic variations and vibration / noise, and to provide a high-quality stepping motor.

  The difference in length between the width S1 and the width S2 may be in a range where the exciting coil 5 (6) is elastically deformed or not disconnected, and is preferably about 0.05 to 0.2 mm depending on the amount of play. .

  Further, the bobbin 16 is formed of a material in which the flange 16a (17a) is inclined toward the outside of the bobbin 16 (that is, a material wider than the width S2 between the outer periphery of the flange 16a and the flange 16b (17a and 17b)). May be. Examples of the material include soft materials such as aluminum, copper, and brass, or resins having elasticity.

  In this case, the exciting coil 5 (6) is elastically deformed by winding a large amount of the exciting coil 5 (6) (that is, increasing the coil winding tension to increase the thickness of the exciting coil 5 (6)). Reference numeral 16a (17a) indicates the elastic deformation of the exciting coil 5 (6), between the inner yoke 3 and the bobbin 16, or between the outer yoke 7 and the bobbin 16 (between the inner yoke 4 and the bobbin 17, or between the outer yoke 8 and the bobbin. 17) between the inner yoke 3 (4) and the outer yoke 7 (8), and elastically deforms according to the amount of gap (backlash) generated between the inner yoke 3 (4) and the outer yoke 7 (8).

  As a result, it is possible to eliminate backlash between components incorporated and incorporated in the motor frame, to prevent characteristic variations and vibration / noise, and to provide a high-quality stepping motor.

  Further, as described above, when a force for pressing the inner yoke 3 (4) and the outer yoke 7 (8) is generated, not only the gap (backlash) but also the outer yoke 7 (8) and the motor frame 14 (15) It is possible to eliminate gaps (backlash) generated between the two.

  As described above, according to the present embodiment, the flange 16a (17a) of the bobbin 16 is configured to be inclined outward from the bobbin 16 from the inner periphery to the outer periphery thereof. Acts to fill and eliminate gaps (backlash) generated between the inner yoke 3 (4) and the bobbin 16 (17) and between the outer yoke 7 (8) and the bobbin 16 (17). It is possible to eliminate backlash between components incorporated and incorporated in the housing, prevent characteristic variations and vibration / noise, and provide a high-quality stepping motor. Further, since the width S2 between the outer periphery of the flange 16a and the flange 16b (17a and 17b) is longer than the width S1 between the inner periphery of the flange 16a and the flange 16b (17a and 17b), There is no need for a spring that presses an internal part that has been conventionally required from one side, a spring space in the motor frame is unnecessary, and the stepping motor can be reduced in size.

  In the above embodiment, the flange 16a (17a) is inclined to the outside of the bobbin 16, but not only the flange 16a (17a) but also the flange 16b (17b) or both flanges. Good. Thereby, the backlash between the components included and incorporated in the motor frame can be further eliminated.

  Further, in the above embodiment, the outer yoke 7 (8) is configured separately from the motor frame 14 (15). However, as shown in FIG. 4, the outer yoke 7 (8) is configured of the motor frame 14 (15). And may be configured integrally. In this case, since there is no gap between the outer yoke 7 (8) and the motor frame 14 (15), the positional accuracy of the outer yoke 7 (8) and the motor frame 14 (15) is increased and characteristics variation and Vibration and noise can be further prevented, and a high-quality stepping motor can be provided. Further, it is possible to provide an inexpensive stepping motor with little variation by eliminating play between the motor frame and the outer yoke.

  Moreover, in the said embodiment, although the said width | variety S2 was comprised so that it might become longer than the width | variety S1, the collar 16a (17a) is comprised with soft materials, such as aluminum, copper, and brass, or resin with elasticity. Thus, before the exciting coil 5 (6) is wound, the width S2 is the same as the width S1, but after the exciting coil 5 (6) is wound, the elasticity of the exciting coil 5 (6) is obtained. The width S2 may be longer than the width S1 by elastic deformation of the flange 16a (17a) according to the deformation. Also in this case, the same effect as the effect of the above-mentioned embodiment is produced.

  Further, in the above embodiment, the flange 16a (17a) and the flange 16b (17b) are integrally formed of the same material with the cylindrical body (not shown) of the bobbin 16 (17). Only the cylindrical body may be formed of a non-magnetic material, and the flange 16a (17a) may be formed of a magnetic material that is elastically deformed.

It is a disassembled perspective view of the stepping motor which concerns on embodiment of this invention. It is sectional drawing in the axial direction of a stepping motor. It is sectional drawing in the axial direction of the bobbin 16 (17). It is a disassembled perspective view which shows the modification of the stepping motor of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor magnet 1a Groove part 3 of rotor magnet 3, 4 Inner yoke 3a, 4a, 7a, 8a Pole teeth 5, 6 Excitation coil 7, 8 Outer yoke 9, 10 Stator 14, 15 Motor frame 16, 17 Bobbin 16a, 17a, 16b , 17b brim

Claims (3)

A hollow cylindrical bobbin having a flange having a central opening at both ends, an inner yoke and an outer yoke having a plurality of pole teeth which are in contact with the flanges at both ends of the bobbin and are alternately arranged in the circumferential direction, An excitation coil wound around the bobbin mounted between the yoke and the outer yoke, and a stator including a motor frame that encloses the inner yoke, the outer yoke, the bobbin, and the excitation coil;
A plurality of pole teeth and a rotor magnet disposed in a coaxial relationship in the stator via a predetermined gap and alternately magnetized to different poles on the peripheral surface;
A stepping motor, wherein a plurality of stators are provided in the axial direction, and an outer peripheral distance between flanges at both ends of the bobbin is longer than an inner peripheral distance between flanges at both ends.   The stepping motor according to claim 1, wherein the outer yoke is integrally formed with the motor frame.   2. The stepping motor according to claim 1, wherein the brim is made of a soft material or an elastic resin.

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