JPH0567189U - Stepping motor - Google Patents

Abstract

(57) [Summary] [Object] To provide a stepping motor in which a coil holding portion is formed by one type of yoke and the coil holding portions can be easily aligned with each other. [Structure] Three notches (52a, 52b, 5) on the side wall
2c) and a cylindrical housing 52, and four yokes 51 of the same shape that fit into this housing. The yoke 51 has a convex portion 51b, and the housing 5
Fit with the two notches (52a, 52b, 52c).
In this way, the housing 52 holds the yoke 51 at a predetermined position and rotation angle, thereby forming a coil holding structure of the stepping motor.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a stepping motor. More specifically, the present invention relates to a stepping motor having a coil holding structure formed by two yokes and one or a plurality of the coil holding parts.

[0002]

[Prior Art]

 As shown in FIG. 1, the coil holding structure of the stator of a small stepping motor that has been conventionally used for autofocus of a video camera has two types of yokes, that is, a yoke A1 and a yoke B2, and a coil 3 from the left and right. By combining them so that they are sandwiched, a coil holding portion for holding the coil 3 is formed.

The yoke A1 has a shape as shown in FIG. 2 and has five magnetic teeth 1a. Moreover, the yoke A1 includes a cylindrical side wall 1c having a cutout 1b. On the other hand, the yoke B2 has the shape shown in FIG. 3, and has five magnetic teeth 2a as with the yoke A1. Further, the yoke B2 has a convex portion 2b, and by fitting the convex portion 2b into the notch 1b of the yoke A1, the positional relationship between the yoke A1 and the yoke B2 is determined. .

In the coil holding portion, the yoke A1 and the yoke B2 are assembled face-to-face as shown in FIG. 4, and the magnetic teeth (1a, 2a) of each yoke are meshed with each other with a predetermined gap therebetween. It will be in a touched state.

[0005]

[Problems to be solved by the device]

 However, in the structure of the conventional example described above, two types of yokes, that is, the yoke A1 and the yoke B2, are required, and therefore two types of molds are required to manufacture each yoke. Further, as shown in FIGS. 2 and 4, the yoke A1 has a complicated shape because the yoke itself has a side wall. For this reason, the process for molding the yoke A1 becomes complicated, and therefore the number of types of dies required for this molding increases, which causes a problem of increasing manufacturing cost.

Further, when assembling into a stepping motor, two sets of coil holding portions formed by the yoke A1 and the yoke B2 are used, and the magnetic teeth (1a, 2a) of each coil holding portion are displaced by a predetermined amount. In the structure of the conventional example, it takes time and effort to adjust the positional relationship between the front and rear holding yokes, which is a problem in terms of product uniformity and mass productivity.

The present invention has been made in view of the above problems, and the coil holding portion is formed by one type of yoke having a simple shape, and the coil holding portions can be easily aligned with each other. It is an object of the present invention to provide a stepping motor which is excellent in product uniformity and mass productivity while reducing the manufacturing cost.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a stepping motor according to the present invention is a coil holding structure in which two yokes are combined to form one coil holding portion, and one or more coil holding portions are formed. And a cylindrical housing having a notch in a side wall, and a yoke having a convex portion that fits in the notch of the housing.

According to another aspect of the invention, there is provided a stepping motor having a coil holding structure in which two yokes are combined to form one coil holding portion and which is formed by one or a plurality of the coil holding portions. A cylindrical housing having a groove on the inner surface of the side wall, and a yoke having a convex portion that fits in the groove of the housing.

[0010]

[Action]

 With the above structure, the coil holding structure is easy to assemble because the mutual positional relationship of the yokes is determined by incorporating the single-shaped yokes into the housing. In addition, since there is only one type of yoke, the manufacturing cost is reduced.

[0011]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a sectional view of a stepping motor having a coil holding structure according to this embodiment. Reference numeral 51 is a yoke for holding the coil 55. Two yokes 51 are set as one set and are combined face-to-face to form a coil holding portion. Reference numeral 52 is a cylindrical housing for holding the yoke 51 in a predetermined positional relationship. Both ends of the housing 52 are covered with flanges 53 and 56, and the housing 52 is housed in a motor case 54 so that two sets of coil holding portions are formed and fixed.

FIG. 6 is a plan view of the yoke 51 according to this embodiment. The yoke 51 in this embodiment is provided with five magnetic teeth 51a and a convex portion 51b for determining the position of the yoke when the housing is mounted. As shown in the figure, when the angle occupied by the magnetic teeth is α and the angle between two adjacent magnetic teeth 51a is β, [(360 ° / number of magnetic teeth) / (number of yokes × 2)] = (α + β) / The convex portion 51b is provided at a position displaced by 8 (that is, 9 ° in this embodiment). Further, the width of the convex portion 51b is h.

FIG. 7 is a perspective view of the housing 52 according to this embodiment. The housing 52 is a cylindrical member, and has three notches (52a, 52b, 52c) on its side wall. The width of each notch (52a, 52b, 52c) is a size that fits into the width (h) of the convex portion 51b of the yoke 51, and these notches (52a, 52b, 52c) and the yoke 51. The relative positions of the respective yokes in the rotation direction and the front-rear direction are determined by fitting with the convex portions 51b. The inner diameter of the housing 52 is determined by the outer diameter of the yoke 51, and the yoke 51 has a size that fits in the housing 52. The above three notches 51a, 51b, 51c are respectively shifted by [(360 ° / number of magnetic teeth) / (number of yokes)] = (α + β) / 4 (that is, 18 ° in this embodiment). Is formed in position. Due to such a positional relationship of the notches, when the yoke 51 is housed face-to-face in the housing 52, the respective magnetic teeth 51a are in a state of meshing with each other. Due to the asymmetric shape of the yoke 51, the two sets of coil holding portions formed by the four yokes 51 are mounted on the housing 52 with a shift of (α + β) / 4.

FIG. 8 is a perspective view showing a state in which the yoke 51 is incorporated in the housing 52. One yoke 51 is attached to each of the notches 52a and 52c, and two yokes 51 are attached to each of the notches 52b. The two yokes 51 attached to the notches 52b are back-to-back and welded to each other by spot welding or the like.

With the above-described structure, the four yokes 51 are positioned by mounting one type of yoke 51 in accordance with each notch of the housing 52.

As described above, according to this embodiment, a coil holding structure having two sets of coil holding portions can be formed by using four yokes 51 of one kind having a simple shape. Since it is possible, only one type of mold is required to mold the yoke. Further, since the positional relationship between the four yokes is determined by the housing 52, the assembling becomes easy, and the uniformity of the products and the mass productivity are improved.

In the present embodiment, the number of magnetic teeth of the yoke is five and the number of yokes used is four, but the number is not limited to this.

<Modification 1> In this embodiment, one convex portion and one notch correspond to one yoke, but the present invention is not limited to this, and as shown in FIG. 9, for example. It is also possible to form the two protrusions (91a, 91b) on the yoke 91 and to provide the housing 92 with the notches (92a, 92b) corresponding to the two protrusions. By providing the plurality of convex portions in this way, the mounting state of the yoke 91 to the housing 92 becomes more stable.

<Modification 2> Further, in the above-described embodiment and modification 1, the position of the yaw is determined by the notch of the housing, but the present invention is not limited to this. For example, as shown in FIG. 10, a groove 102a may be formed on the inner surface of the side wall of the housing 102, and the groove 102a and the convex portion 101a of the yoke may be fitted together. By thus positioning the yoke 101 with the groove 102a of the housing 102, it becomes possible to eliminate the motor case in the above-described embodiment.

[0021]

[Effect of the device]

 As described above, according to the present invention, the coil holding portion is formed by one type of yoke having a simple shape, and the coil holding portions can be easily aligned with each other. Further, due to the structure of the holding coil, the manufacturing cost is reduced, and the stepping motor having excellent product uniformity and mass productivity is provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a conventional stepping motor.

FIG. 2 is a plan view of a coil holding yoke in a conventional stepping motor.

FIG. 3 is a plan view of a coil holding yoke in a conventional stepping motor.

FIG. 4 is a perspective view showing a combination of yokes of a coil holding portion in a conventional stepping motor.

FIG. 5 is a diagram showing a structure of a stepping motor according to the present embodiment.

FIG. 6 is a plan view of a coil holding yoke according to the present embodiment.

FIG. 7 is a perspective view of a housing according to the present embodiment.

FIG. 8 is a perspective view showing a method of assembling the housing and the yoke in the coil holding unit according to the present embodiment.

FIG. 9 is a perspective view showing an assembly of a yoke and a housing according to a modified example 1.

FIG. 10 is a perspective view showing an assembly of a yoke and a housing according to a modified example 2.

[Explanation of symbols]

 51 yoke 51a magnetic tooth 51b convex portion 52 housing 52a, 52b, 52c notch for yoke positioning 53 flange 54 motor case 55 coil

Claims (2)

[Scope of utility model registration request] 1. A stepping motor having a coil holding structure formed by combining two yokes having n magnetic teeth to form one coil holding portion and having one or a plurality of the coil holding portions. In the circumferential direction on the side wall [(360 ° / n) / (number of yokes)]
A cylindrical housing having a plurality of notches spaced apart from each other, and a convex portion that fits into the notches of the housing are arranged in the circumferential direction from the center of the magnetic teeth [(360 ° / n) / (number of yokes × 2)]. A stepping motor, comprising: a yoke that is offset; and the coil holding portion is formed by fitting the yoke to the housing. 2. A stepping motor having a coil holding structure formed by combining two yokes having n magnetic teeth to form one coil holding portion, and having one or a plurality of the coil holding portions. , A cylindrical housing having a plurality of grooves on the inner surface of the side wall and circumferentially spaced apart by [(360 ° / n) / (number of yokes)]; [(360 ° / n) / (number of yokes × 2)] circumferentially offset from the center, and the coil holding portion is formed by fitting the yoke to the housing. Stepping motor to do.