JP2007166878A - Stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor capable of reducing a total length in axial direction by adopting a configuration of a longitudinal loading of the motor that is preferable for reduction in diameter, reducing the number of parts, and performing an assembly with the use of a little time and manpower and with high precision, and obtaining high torques satisfactorily also regarding torque characteristics. <P>SOLUTION: Two stators S1, S2 with A phase, B phase are disposed to be sandwiched behind each other in axial direction of a rotor 1. A coil 3 with A phase at one shaft side, and a coil 3 with B phase at the other shaft side with respect to the rotor 1 are disposed concentrically, respectively. The configuration is such that an inner yoke plate 4 and an outer yoke plate 5 are sandwiched within the coil 3 with each phase, and comb teeth-shaped pole teeth 2 extending from these yoke plates 4, 5 toward the rotor 1 side are aligned to be sandwiched in circumferential direction and faces an outer periphery of the rotor 1. The pole teeth 2 are formed at its end in a predetermined concave shape, and the ends of the pole teeth 2 of both phases facing to each other surrounding outer periphery of the rotor 1 are brought into contact with each other to be engaged with each other. The engagement of the ends of the pole teeth 2 of both phases fixes mutual positions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a claw pole type stepping motor. More specifically, the constituent elements of two A-phase and B-phase stators are arranged in front and rear in the axial direction of the rotor, and the outer periphery of the rotor It is related with the improvement of the shape of the stator side inductor (pole tooth) in the two-phase structure which reduced the component located in this.

  One well known type of stepping motor is the claw pole type. This is a structure in which a large number of magnetic poles are arranged on the outer periphery of the rotor, and there are comb-like inductors (pole teeth) on the stator side so that the pole teeth are engaged with each other in the A phase and the B phase. Therefore, it has a merit that the resolution is relatively good and the manufacturing cost can be reduced.

In the claw-pole type stepping motor, as seen in Patent Document 1, etc., the constituent elements of the two stators of the A phase and the B phase are arranged to be sandwiched back and forth in the axial direction of the rotor in order to reduce the diameter. A two-phase stepping motor in which the number of components located on the outer periphery of the rotor is reduced is known. The stepping motor of this Patent Document 1 is called a so-called vertically stacked motor. A phase coil is concentrically arranged on one shaft side with respect to the rotor, and a B phase coil is concentrically arranged on the other shaft side. The inner yoke plate and the outer yoke plate are sandwiched between the coils of each phase, and comb-shaped pole teeth extending from the yoke plate toward the rotor are sandwiched in the circumferential direction so as to face the outer periphery of the rotor. It adopts a configuration to do.
Japanese Patent Laid-Open No. 63-110951

  However, such conventional stepping motors have the following problems. The stepping motor disclosed in Patent Document 1 and the like is a structure suitable for reducing the diameter because there are few components located on the outer periphery of the rotor, but the components such as the coil on the stator side are continuous in the axial direction. Conversely, there is a problem that the total length in the axial direction becomes long.

  Further, since the pole teeth extend from both sides of the rotor shaft toward the center, it is necessary to arrange a ring member at the center in order to separate both the A phase and the B phase. This also becomes a factor of increasing the overall length in the axial direction, increases the number of parts, and takes time for assembly.

  In a two-phase motor, since it is necessary to set a predetermined phase shift value between the A phase and the B phase with an electrical angle, the pole teeth of the A phase and the B phase are arranged so as to be shifted to a predetermined position. Is provided with notches and protrusions for alignment, or a jig member for alignment to adjust positioning during assembly. Therefore, in the conventional configuration, the assembly takes time, the alignment accuracy is lowered, and the design performance cannot be obtained.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and its object is to adopt a configuration of a vertically stacked motor that is preferable for reducing the diameter, to reduce the overall length in the axial direction, to reduce the number of parts, and to perform assembly with high accuracy without trouble. Therefore, an object of the present invention is to provide a stepping motor that can obtain a high torque with good torque characteristics.

  In order to achieve the above-described object, a stepping motor according to the present invention has a rotor made of permanent magnets divided in the circumferential direction and magnetized in multiple poles, and each component of two stators of A phase and B phase. In a stepping motor in which the stator is arranged so as to be sandwiched back and forth in the axial direction of the rotor, and in each stator, the pole teeth as inductors are arranged in a comb shape in the circumferential direction and surrounded by the outer periphery of the rotor. It is configured to have a shape or a concave shape, and the tips of both-phase pole teeth facing each other surrounding the outer periphery of the rotor are brought into contact with each other and engaged with each other.

  Further, the tip of the pole teeth may be formed in an edge where the straight part is appropriately reduced, and may be set in a shape that reduces the contact part in the facing contact of both phases. For example, the tip of the pole teeth can be convex, and the central protrusion can be set as a circular arc part having a predetermined curvature, and the corners on both sides can also be set as circular arc parts having a predetermined curvature.

  By adopting such a configuration, in the present invention, both the A phase and B phase are pole teeth facing each other and meshing with their tips in contact with each other, so that a ring member as in the conventional configuration is not required at the center. Since the tips of the pole teeth are engaged with each other, their positions are determined, and positioning is completed for both the A phase and the B phase.

  Since the positional relationship between both the A phase and the B phase is determined by meshing the tips of the pole teeth, the positional relationship between both phases can be adjusted by appropriately setting the shape of the pole teeth. Since the phase shift relationship in both the A phase and the B phase is determined by the pole tooth shape setting, there is no influence of the tolerance of the positioning member as in the conventional configuration, and the assembly can be performed with high accuracy.

  The tip of the pole tooth may be either a convex shape or a concave shape, as long as both opposing phases can be engaged with each other. In this meshing, it is preferable that the number of parts to be contacted is small and the area is small. This is because, when the area of the contact portion is small, the vicinity of the contact portion is magnetically saturated, and the magnetic flux hardly flows between the A phase and the B phase. And since the magnetic flux is not concentrated at the tip of the pole tooth as compared with the root, the reduction of the torque is not so much. Therefore, even when the tips of the pole teeth are brought into contact, the leakage magnetic flux between the A phase and the B phase becomes a small value, so that the action of reducing torque can be suppressed, and the pole teeth of both phases approach. A large maximum torque can be obtained, which is more preferable.

  In the stepping motor according to the present invention, both the A phase and the B phase have the pole teeth facing each other and are engaged with each other by contacting the tips of the phases, so that the positions of both the A phase and the B phase are determined. Complete. In this case, a member for separating both phases and a member for positioning are unnecessary, the number of parts can be reduced, and assembly can be performed with high accuracy without trouble. And the total length of the motor in the axial direction can be reduced, and the size can be reduced. Even when the tips of the pole teeth are brought into contact with each other, the leakage magnetic flux between the A phase and the B phase becomes a small value, and the pole teeth of both phases approach each other, so that a high torque can be obtained with good torque characteristics.

  1 and 2 show a preferred embodiment of the present invention. In this embodiment, the stepping motor has a rotor 1 made of permanent magnets, and the constituent elements of the two stators S1 and S2 of the A phase and the B phase are arranged to be sandwiched back and forth in the axial direction of the rotor 1, The stators S1 and S2 adopt a two-phase structure in which inductors (pole teeth 2) are arranged in a comb-like shape in the circumferential direction and surrounded by the outer periphery of the rotor 1 to form a so-called vertically stacked motor.

  The two stators S <b> 1 and S <b> 2 of the A phase and the B phase have the same configuration and face each other in the axial direction of the rotor 1. That is, with respect to the rotor 1, an A-phase coil 3 is arranged concentrically on one axis side, and a B-phase coil 3 is arranged concentrically on the other axis side. The plate 4 and the outer yoke plate 5 are sandwiched. Comb-shaped pole teeth 2 extending from the yoke plates 4 and 5 toward the rotor 1 are arranged so as to face the outer periphery of the rotor 1 while being sandwiched in the circumferential direction.

  The rotor 1 has a rotating shaft 10 at the center of a cylindrical permanent magnet, and the surface of the permanent magnet is divided into n parts in the circumferential direction so as to be magnetized into alternating poles of N and S poles. Yes. The magnetic pole 6 may be formed from a single magnet, and these may be connected together to form a cylindrical permanent magnet.

  The rotor 1 and the two stators S1 and S2 disposed so as to be sandwiched between the rotor 1 and the front and rear thereof are accommodated in a cylindrical housing, although not illustrated. The housing is provided with front and rear bracket plates fitted together so that the rotating shaft 10 of the rotor 1 is rotatably supported by a bearing portion.

  The coil 3 has a configuration in which a wire rod is wound around a cylindrical bobbin 7, and is assembled by fitting the hole portion of the bobbin 7 to the cylindrical portion 8 of the inner yoke plate 4.

  The inner yoke plate 4 and the outer yoke plate 5 have a circular substrate 9, and the peripheral edge of the substrate 9 is partially raised to form comb-shaped pole teeth 2 in a line. The inner yoke plate 4 is integrally provided with a cylindrical portion 8 at the center of the substrate 9, and a rotating shaft 10 is rotatably fitted inside the cylindrical portion 8, and the coil 3 is assembled on the outer side of the cylindrical portion 8. ing.

  The array of pole teeth 2 corresponds to the array of magnetic poles 6 of the rotor 1, and the tips of the pole teeth 2 are formed in a predetermined convex shape. These pole teeth 2 face each other in both the A phase and the B phase, and are configured so that the tips of the pole teeth 2 of both phases facing each other surrounding the outer periphery of the rotor 1 are brought into contact with each other and meshed. In this meshing relationship, the A phase and the B phase are displaced by a predetermined amount in the rotational direction, and this positional shift changes according to the meshing relationship, that is, the shape of the meshing tip. In a two-phase motor, since it is necessary to set a predetermined phase shift value by an electrical angle between the A phase and the B phase, the position at which the predetermined phase shift value is obtained by appropriately adjusting the shape of the meshing tip The gap is set.

  Here, the tip of the pole tooth 2 may be either a convex shape or a concave shape as long as the opposite ends of both phases can be engaged with each other, and the mutual positions can be determined by the engagement. And preferably, the edge part which contacts is formed in the edge which reduced the linear part suitably, and is formed in the shape where a mutual contact part reduces in the opposing contact of both phases. In the present embodiment, the shape of the tip is a convex shape as shown in FIG. 3, the central protrusion is set as an arc portion having a predetermined curvature r1, and the corners on both sides are also set as arc portions having a predetermined curvature r2. I have to.

  The tip shape of the pole teeth 2 is not limited to the convex shape as in the present embodiment. The tip shape can be appropriately changed as shown in FIGS. 4A to 4D, for example. The tip shape of the pole teeth 2 may be formed in a sharp shape as shown in FIG. 4A, or may be formed in a blunt shape as shown in FIG. 4B. Alternatively, as shown in FIG. 4 (c), it may be formed in a polygonal pointed shape, or as shown in FIG. 4 (d), it may be formed in a substantially semicircular shape in which the tip edge part is a curved line. Good.

  In this way, the A-phase and B-phase both have the pole teeth 2 facing each other and are brought into contact with each other so that the ring members as in the conventional configuration are not required at the center. And since the front-end | tip of the pole tooth | gear 2 is meshed | engaged, a mutual position is decided and positioning is completed about both A phase and B phase. Therefore, a member for separating both phases and a member for positioning are unnecessary, the number of parts can be reduced, and assembly can be performed with high accuracy without trouble. And the total length of the motor in the axial direction can be reduced, and the size can be reduced.

  In this case, since the positional relationship between both phases A and B is determined by meshing the tips of the pole teeth 2, the positional relationship between both phases can be adjusted by appropriately setting the shape of the pole teeth 2. Since the phase shift relationship in both the A phase and the B phase is determined by the shape setting of the pole teeth 2, there is no influence of the tolerance of the positioning member as in the conventional configuration, and the assembly can be performed with high accuracy.

  Further, the tip of the pole tooth 2 only needs to be able to mesh both facing phases, and the shape thereof can be set appropriately. In this meshing, it is preferable that there are few contact parts and the area is small. This is because, when the area of the contact portion is small, the vicinity of the contact portion is magnetically saturated, and the magnetic flux hardly flows between the A phase and the B phase. And since the magnetic flux is not concentrated on the front-end | tip of the pole tooth 2 compared with the root, the reduction of torque is not so much. Therefore, even when the tip of the pole tooth 2 is brought into contact, the leakage magnetic flux between the A phase and the B phase becomes a small value, and the action of reducing the torque can be suppressed. As a result, high torque can be obtained with good torque characteristics.

  Furthermore, since the A phase and the B phase are structurally symmetric, the magnetic circuits due to the contact of the pole teeth 2 of both phases are substantially the same. Therefore, even when the pole teeth 2 of both phases are brought into contact with each other and engaged, no cogging torque is generated at the same period as the pitch of the magnetic poles 6 of the rotor 1.

  In order to demonstrate the effect of the present invention, analytical calculation is performed for a setting example in which the shape of the tip of the pole tooth is a convex shape as shown in FIG. 3 and a comparative example with a conventional configuration in which the tip of the rectangular pole tooth is non-contacting, The torque characteristics were verified.

As an example of setting the pole teeth according to the present invention, the curvature r1 of the central protrusion and the curvature r2 of the corners on both sides are appropriately changed in the convex shape shown in FIG. To 10 were prepared. As a comparative example, the tip shape of the pole teeth was rectangular, and the A and B phases were not contacted with a predetermined gap, and model numbers 1 to 3 shown in Table 1 were prepared.

  As a result of performing analytical calculations on these models, as shown in Table 1, it was confirmed that the maximum static torque can be obtained in the setting example according to the present invention as well as the conventional value. In model numbers 4 to 7, it was confirmed that the tips of the pole teeth were set so that the contact edges of each other were reduced, and that the maximum static torque could be obtained higher when the contact area was made smaller. The maximum static torque shown in Table 1 has the torque value in model number 1 as a reference value of 100%, and other models show relative values.

  FIG. 5 is a graph showing torque characteristics in one-phase excitation. In the figure, the torque characteristics of model number 7 and model number 1 are shown, and as is clear from the figure, it was confirmed that torque characteristics equivalent to those of the prior art can be obtained.

  That is, torque characteristics can be obtained satisfactorily even if a configuration in which the tips of the pole teeth are brought into contact with each other in the A-phase and B-phase orientations, and as a result, the total axial length of the motor can be reduced, resulting in a smaller size. Can be made. Moreover, if the axial total length is set to be equal to that of the conventional configuration, the area of the pole teeth can be increased and a larger torque can be obtained.

1 is an exploded side view of a preferred embodiment of a stepping motor according to the present invention. It is a side view of the stepping motor shown in FIG. It is an expanded view which expands and shows the front-end | tip part of a pole tooth (inductor). It is an expanded view which expands and shows the tip shape in the other example of a pole tooth (inductor), (A) is an acute angle shape, (B) is an obtuse angle shape, (C) is a polygonal shape, (D) is a substantially semicircle. This is an example of a shape. It is a graph which shows the torque characteristic in 1 phase excitation.

Explanation of symbols

1 rotor 2 pole teeth (inductor)
3 Coil 4 Inner yoke plate 5 Outer yoke plate 6 Magnetic pole 7 Bobbin 8 Tube portion 9 Substrate 10 Rotating shaft S1, S2 Stator

Claims (3)

The rotor is composed of permanent magnets divided in the circumferential direction and magnetized into multiple poles, and the constituent elements of the two A-phase and B-phase stators are arranged so as to be sandwiched back and forth in the axial direction of the rotor. Then, in the stepping motor in which the pole teeth that are the inductors are arranged in a comb shape in the circumferential direction and surrounded by the outer periphery of the rotor,
A stepping motor characterized in that the tips of the pole teeth are convex or concave, and the tips of the pole teeth of both phases facing each other surrounding the outer periphery of the rotor are brought into contact with each other and meshed with each other.   The tip of the pole tooth is formed in an edge where the straight part is appropriately reduced, and is set to a shape that reduces the contact part of each other in the facing contact of both phases. Stepping motor.   The tip of the pole teeth has a convex shape, the central protrusion is an arc portion having a predetermined curvature, and the corners on both sides are also arc portions having a predetermined curvature. Stepper motor.

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