JP2003189584A - Stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor in which a positional deviation of a stator core and a coil bobbin hardly occurs at an assembling time of the stator core and the coil bobbin so that occurrence of a characteristic abnormality, a vibration, a noise or the like can be suppressed and which is stable in quality. <P>SOLUTION: The stepping motor M comprises stators A, B having the recess stator core 20 and the coil bobbin 30 arranged between the stator cores 22. The bobbin 30 has a pair of side plates 31, 32 having central holes, a body 33 for coaxially coupling the holes, a terminal mounting part 34 formed at the plate 31, and a winding 30a. The cores 20, 22 have stator yokes 20a, 22a, and poles 20b, 22b axially extended and having narrower width toward a distal end. The bobbin 30 has a pole containing part 39 of substantially the same shape as those of poles 20b, 22b formed on an inside face of the body 33 thereof. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor, and more particularly to a permanent magnet type stepping motor in which claw pole type stators are laminated.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet type stepping motor comprises a stator core having a plurality of convex magnetic poles and a coil bobbin around which a winding is wound, and the coil bobbin is sandwiched between the two stator cores. Generally, it has a pole type structure).

FIG. 5A is a front view of the coil bobbin 30,
A cross-sectional view taken along the line XX is shown in FIG. The coil bobbin 30 includes a pair of parallel annular side plates 31 and 32.
A cylindrical body 33 that connects them coaxially is integrally resin-molded. A terminal mounting portion 34 is formed on the side plate 31 so as to extend outward in the radial direction and to project axially opposite to the side plate 32 by a predetermined height. A predetermined number of terminals 35 are attached to the terminal attachment portion 34.

Positioning projections 36 and 37 are formed on the side plates 31 and 32 so as to project in the axial direction. The winding 30a is wound around the body 33, and the end of the winding 30a is connected to the terminal 35 so as to be entwined.

FIG. 6 (A) is a front view of a stator core 22 which constitutes a stator with the coil bobbin 30 sandwiched therebetween, and FIG. 6 (B) is a sectional view taken along the line YY. The stator core 22 includes an annular planar stator yoke portion 22a,
And a plurality of magnetic poles 22b extending from the inner edge portion of the stator yoke portion 22a in a substantially right-angled direction.

A positioning hole 22c and a cutout portion 22d are formed in the stator yoke portion 22a. When the stator core 22 is assembled to the coil bobbin 30, the positioning of the stator core 22 and the coil bobbin 30 is performed by fitting the positioning holes 22c of the stator core 22 and the positioning protrusions 36 and 37 of the coil bobbin 30 in a predetermined combination. Be seen.

Positioning hole 22c and positioning protrusion 3
6 and 37 are arranged at predetermined positions in the circumferential direction, and by fitting them in a predetermined combination as described above, a plurality of stator cores 22 arranged in the stepping motor have their magnetic poles 22b. It is displaced by a predetermined angle in the circumferential direction.

The stator core 22 is replaced by the coil bobbin 3
When it is inserted from the side plate 31 side of 0, the coil bobbin 30
A notch 22d is formed in the stator core 22 in order to avoid the axially projecting terminal mounting portion 34 formed on the stator core 22.

[0009]

As described above, when the stator core 22 is assembled to the coil bobbin 30, the stator core 22 and the stator core 22 are inserted so that the positioning protrusions 36 and 37 of the coil bobbin 30 fit into the positioning holes 22c of the stator core 22. After matching the relative positions of the coil bobbins 30, the stator core 22 is attached to the coil bobbins 30.

However, when assembling the stator core 22 and the coil bobbin 30, they may be fitted in a state in which they are slightly displaced from a predetermined position. In this case, since the positioning protrusions 36 and 37 of the coil bobbin 30 are made of synthetic resin, the positioning protrusions 36 and 37 are crushed by the peripheral edge of the positioning hole 22c of the stator core 22.
However, even in that case, there is a disadvantage that the stator core 22 and the coil bobbin 30 are assembled in a state of being displaced from a predetermined position.

Moreover, it is difficult to discriminate the stator assembled in such a shifted state and prevent the stator from flowing out to the subsequent stepping motor assembling step. Then, in the stepping motor in which the stator is assembled, the stator core 22 is not arranged at a predetermined position, and the relative position of the magnetic pole 22b of the stator core 22 is also displaced.
There was a problem that noise was generated.

In view of the above problems, an object of the present invention is to prevent the positional deviation of the stator core and the coil bobbin from occurring when the stator core and the coil bobbin are assembled, and to suppress the occurrence of characteristic abnormality, vibration, noise and the like. To provide a stable stepping motor.

[0013]

According to the stepping motor of claim 1, in the stepping motor having a stator in which a coil bobbin is arranged between two stator cores, the coil bobbin has a central portion. The stator core includes a pair of side plates having holes, a body portion coaxially connecting the central holes of the pair of side plates, a terminal mounting portion formed on one of the side plates, and a winding. And a magnetic pole that is axially extended from the edge of the central hole of the stator yoke portion and has a width that is narrower toward the tip. The inner surface of the body portion of the coil bobbin is substantially the same as the magnetic pole. This is solved by forming at least one magnetic pole housing having the same shape.

When the stator core and the coil bobbin are assembled, if the tip end of the magnetic pole whose width is narrower from the axial direction toward the tip of the stator core is inserted into the magnetic pole accommodating portion of the coil bobbin, the stator core and the coil bobbin are further brought closer to each other.
The magnetic pole whose width is narrower toward the tip is subjected to a component force that automatically rotates in the circumferential direction so as to fit into the magnetic pole housing portion, and the position is corrected.

Therefore, when assembling the stator core and the coil bobbin, it is not necessary to perform highly accurate alignment, and even if the stator core and the coil bobbin are inserted in a state in which they are misaligned with each other, they are automatically corrected, which facilitates the assembly. At the same time, the generation of defective products can be suppressed.

Further, as described in claim 2, since the magnetic pole accommodating portion is formed by the protrusion formed on the inner surface of the body portion of the coil bobbin, when the stator core and the coil bobbin are assembled. Even if they are inserted in a state where they are displaced in the circumferential direction, the function of automatically correcting the positional deviation works by the sliding contact between the ridges and the magnetic poles that are substantially parallel to each other in the circumferential direction, which is preferable. .

Further, as described in claim 3, all the magnetic pole accommodating portions are formed on the inner surface of the body portion of the coil bobbin in the same number as the number of magnetic poles of the two stator cores. Since the magnetic poles are regulated by the magnetic pole accommodating portion, when they are assembled, variations in the characteristics of the stepping motor are less likely to occur, which is preferable.

Further, according to a fourth aspect of the present invention, the stator is coaxially laminated, and at least the side plate or terminal mounting portion of the coil bobbin is engaged with the side plate or terminal mounting portion of the coil bobbin facing the side plate or terminal mounting portion. Since the positioning projections and holes are formed, the circumferential positioning between the stacked stators can be accurately performed, which stabilizes the operating characteristics, which is preferable.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. 1 is an exploded perspective view of a stepping motor of an embodiment, FIG. 2 is a front view of a stator core of the embodiment (A) and a sectional view taken along line AA (B), and FIG. 3 is a front view of a coil bobbin of the embodiment (A). 4B is a partial enlarged view of the coil bobbin of another embodiment.

The same elements as those of the conventional example will be described with the same reference numerals. The arrangement, shape, etc. described below are not intended to limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

As shown in FIG. 1, the stepping motor M of this embodiment has a single concave stator core 2 in which two housings 11 and 12 are provided with magnetic poles 20b constituting a stator.
0, the stator core 22 with the magnetic pole 22b, the winding 30a
The coil bobbin 30 around which is wound, the plate 13, the rotor 40, the outer gear 51 and the internal gear 52 that configure the speed reducer 50, and the like are assembled and configured.

Output side housing (upper side in FIG. 1,
In the following, referred to as “upper housing” 11 includes a speed reducer 5
Hole 11 for exposing the outer gear 51 which constitutes 0
a is formed.

A housing located on the side opposite to the output side (lower side in FIG. 1, hereinafter referred to as "lower side housing") 12
Comprises an extending portion 12a and a cylindrical recess 12b which is continuous with the extending portion 12a and accommodates the stator. A bearing recess (not shown) is formed in the center of the recess 12b. Then, two positioning protrusions 12d (only one is shown) are formed at predetermined positions on the bottom surface on the side wall side in the cylindrical recess 12b.

Further, ribs 12h are formed so as to project in the vertical direction on the side wall inside the cylindrical recess 12b. In this example, three ribs 12h are provided at substantially equal intervals. The concave stator core 20 is press-fitted into the concave portion 12b,
It is held in place by the ribs 12h. Further, a cutout portion 12e for positioning the terminal 35 is formed on the side opposite to the extending portion 12a.

Further, on the upper surface of the four corners of the lower housing 12, there are formed four protrusions 12f for engaging with the holes of the upper housing 11 and caulking and attaching.

As shown in FIG. 1, the stator is composed of two layers of a stator A and a stator B, and has a magnetic pole 22b or a magnetic pole 20.
b having a stator core 22 or a concave stator core 2
0, the coil bobbin 30 has a claw pole type structure.

The upper layer stator A includes two stator cores 2
It is laminated so as to sandwich the coil bobbin 30 between the two, and the lower stator B is laminated so as to sandwich the coil bobbin 30 between the concave stator core 20 and the stator core 22.

As shown in FIG. 2, the stator core 22 is
An annular planar stator yoke portion 22a and eight magnetic poles 22b extending from the inner peripheral end of the stator yoke portion 22a in a substantially perpendicular direction are provided.

The magnetic poles 22b are formed by sheet metal working at regular intervals (45 ° in this example). And magnetic pole 2
The height of 2b is substantially the same as the height of the coil bobbin 30, and is formed in a trapezoidal shape such that the width becomes narrower toward the tip.

Further, the stator core 22 is formed with a cutout 22d in order to avoid the terminal mounting portion 34 formed on the coil bobbin 30 so as to project in the axial direction when the stator core 22 is inserted into the coil bobbin 30. . The magnetic pole 22b is formed at a position that is displaced from the cutout portion 22d by approximately 6 ° in the circumferential direction.

Similar to the stator core 22, the concave stator core 20 is formed with eight magnetic poles 20b at a constant interval (45 ° in this example) by sheet metal working. A cylindrical housing wall 20e is formed on the outer peripheral end of the stator yoke portion 20a of the concave stator core 20 in the same direction as the direction in which the magnetic pole 20b extends.

Further, a cutout portion 20d for positioning the terminal 35 is formed in a part of the housing wall 20e. Although the cutout portion 20d is largely cut out to the front side for convenience of description in the drawing, in reality, when the coil bobbin 30 is inserted into the concave stator core 20, the terminal attachment portion 34 is exposed to the outside. It has been cut out only to the extent that it can be encountered.

The height of the accommodating wall 20e is substantially the same as the height of the lower housing 12. Further, the stator yoke portion 20a has two positioning holes for the lower housing 12.

As shown in FIG. 3, the coil bobbin 30 is provided with a pair of parallel annular side plates 31 and 32 and an integrally resin-molded cylindrical body portion 33 that coaxially connects these side plates. The terminal mounting portion 34 is formed on the base member 31 so as to extend outward in the radial direction and project a predetermined height in the axial direction.

Two terminals 35 are attached to the terminal attachment portion 34. The winding 30a has its end connected to one terminal 35, is wound around the body 33, and is then connected to the other terminal 35 at its end.

Further, 16 guides 38, which are inclined at a predetermined angle from the axial direction, are formed on the inner wall of the body 33 at predetermined positions. The guide 38 forms a magnetic pole housing 39 by two adjacent guides 38. The magnetic pole accommodating portion 39 includes a coil bobbin 30 and a concave stator core 20,
The circumferential end surfaces of the magnetic poles 20b and 22b are configured to abut the guide 38 when the magnetic pole 22 is inserted.

Coil bobbin 30 around which winding 30a is wound
Are sandwiched by the stator core 22 or the concave stator core 20 as described above to form the stator A and the stator B. The stator A and the stator B are stacked and arranged in the recess 12b of the lower housing 12. At this time, the surfaces of the stator A and the stator B facing each other are the side plate 31 side of the coil bobbin 30.

The rotor 40 of this example comprises a rotor body 40a having a magnet and a rotor shaft 40b formed integrally with the rotor body 40a. A gear portion 40c is formed on the output side of the rotor shaft 40b, that is, on the end side of the rotor shaft on the plate 13 side. This gear part 4
0c meshes with the internal gear 52 of the speed reducer 50.

The speed reducer 50 is composed of an internal gear 52 and an outer gear 51 each having upper and lower two-stage gears. The internal gear 52 is pivotally supported by the protruding shaft 13a of the plate 13 and the boss portion 13b.

Next, the assembling of each member of the stepping motor M having the above structure will be described with reference to FIG. Assembling is performed by first sequentially stacking the other constituent members of the lower layer stator B in one concave stator core 20 and further sequentially stacking the respective constituent members of the upper layer stator A. Then, in the lower housing 12, the rotor 40, the stator A and the stator B, the plate 13, the speed reducer 50, and the upper housing 1
The layers are laminated in the order of 1, and finally the projection 12f is heat-crimped and fixed.

The assembly of each member will be described in more detail. First, the coil bobbin 30 of the lower layer stator B is placed in the concave stator core 20. Coil bobbin 30
Is inserted into the concave stator core 20 from the predetermined position in the circumferential direction with an accuracy of about several degrees and is pushed, the slanted guide 38 makes sliding contact with one end surface of the magnetic pole 20b, whereby the coil bobbin 30 moves in the circumferential direction. It receives the component force and is rotated to automatically correct the position.

Next, the stator core 2 is attached to the coil bobbin 30.
Stack two. When the stator core 22 is inserted into the coil bobbin 30, the position correction is performed while the guide 38 and the magnetic pole 22b are in sliding contact with each other as described above.

In this way, the lower layer stator B is assembled, and the magnetic poles 20b of the concave stator core 20 and
The magnetic poles 22b of the stator core 22 are arranged at regular intervals (22.5 ° in this example).

Next, the upper layer stator A is assembled. First, the stator core 22 of the upper layer stator A is arranged on the stator core 22 of the lower layer stator B described above.
The lower layer stator B is placed so as to face the stator core 22 in the opposite direction, that is, with the magnetic pole 22b facing upward. At this time, the notch 22d of the stator core 22 of the upper layer stator A is arranged so as to be aligned with the terminal mounting portion 34 of the lower layer stator B.

Next, the stator core 22 of the upper stator A
The coil bobbin 30 of the upper-layer stator A is placed on the above. At this time, the coil bobbin 30 and the stator core 22 are assembled in the same manner as when the lower layer stator B is laminated. Further, the stator core 22 of the upper layer stator A is placed on the coil bobbin 30 with the magnetic pole 22b facing downward. In this way, also in the upper layer stator A, the magnetic poles 22a of each stator core 22 are arranged at regular intervals (22.5 ° in this example).

When the stator A and the stator B are laminated as described above, the convex magnetic poles of each stator core can be laminated in a state of being displaced by a constant distance (about 11 ° in this example).

Then, the rotor 40 is inserted through the washer 53 from the side of the rotor shaft 40b having no gear portion 40c.

Next, the upper layer stator A and the lower layer stator B laminated as described above are press-fitted into the lower housing 12. At this time, the cutout portion 20d of the concave stator core 20 is directed toward the cutout portion 12e of the lower housing 12, and the positioning projection 12d of the lower housing 12 is engaged with the positioning hole of the concave stator core 20.

Next, the plate 13 is placed. At this time, the upper surface of the stator A contacts the plate 13. Next, the internal gear 52 is pivotally supported by the protruding shaft 13a and meshed with the gear portion 40c of the rotor 40. And
The outer gear 51 is pivotally supported by the protruding shaft 13c.

Finally, the upper housing 11 is mounted, and the upper and lower housings are heat-crimped to integrate the upper and lower housings. At this time, since the stator core 22 of the stator A is pressed by the plate 13, the stator A and the stator B are brought into closer contact with each other. In this way, the stepping motor M is completed.

As described above, according to this embodiment,
It has the following effects. (1) Conventionally, the positioning hole formed in the annular stator yoke portion of the stator core and the positioning protrusion formed in the coil bobbin are accurately positioned and fitted into each other.

In this embodiment, the stepping motor M
Coil bobbin 3 forming the stator A and the stator B of
0 has a concave stator core 2 on the inner wall of its body 33.
Insertion guide 3 for 0 and 22 convex magnetic poles 20b and 22b
8 was formed.

With the coil bobbin 30 having the above structure, the guide 38 of the coil bobbin 30 and the magnetic poles 20b and 22b of the concave stator cores 20 and 22 are slidable even when the coil bobbin 30 and the coil bobbin 30 are inserted with their positions deviated from each other. By touching, the position is automatically corrected.

As a result, the concave stator cores 20, 22 are
When assembling the coil bobbin 30 with the coil bobbin 30, it is not necessary to accurately fit the positioning hole and the positioning protrusion,
Assembly performance is improved. Further, conventionally, there was a case where the stepping motor M had abnormal characteristics, vibration, and noise due to improper fitting due to misalignment of the positioning hole and the positioning projection, but these can be easily prevented. Become.

(2) Further, conventionally, a plurality of positioning holes are formed in the stator core, but the concave stator cores 20 and 22 of the present embodiment are formed with positioning holes as compared with the conventional stator core. Since the number of holes is small and the magnetic flux can be efficiently transmitted correspondingly, the magnetic efficiency of the stepping motor M can be improved.

The embodiment of the present invention may be modified as follows. In the above-described embodiment, the stator A is placed on the stator B in such a manner that the terminal mounting portion 34 of the stator A and the terminal mounting portion 34 of the stator B overlap each other, and the two terminal mounting portions 34 have the concave stator core 20. It comes to face from the notch 20d.

In this case, the stator A and the stator B may be slightly displaced from the predetermined relative positions. Therefore, as shown in FIG. 4, the fitting hole 34a and the fitting projection 34 are formed on the axially outer surface of the terminal mounting portion 34 on the side plate 31.
b may be provided.

In this case, since the terminal mounting portions 34 of the coil bobbins 30 of the stator A and the stator B are laminated so as to face each other, the fitting hole 34a and the fitting protrusion 34b are fitted together. This allows the stator A and the stator B to be accurately aligned. In addition, the fitting protrusion 34
By increasing the height of b, it is possible to maintain a gap between the stator A and the stator B and prevent them from being electrically connected to each other.

A fitting protrusion may be further provided on the side plate 31 in order to stably hold the gap. in this case,
The stator core 22 also needs to be provided with an insertion hole for the fitting protrusion. At this time, even if the stator core 22 and the coil bobbin 30 are inserted with a positional deviation, the fitting protrusion is prevented from coming into contact with the insertion hole and the stator yoke portion 22a of the stator core 22 and being crushed. It is preferable that the diameter of the insertion hole is larger than the diameter of the fitting protrusion.

The fitting hole 34a and the fitting projection 34 are also provided.
Instead of forming b, the coil bobbin 30 may be provided with a protrusion formed on the side plate of the conventional coil bobbin. However, at this time, it is necessary to form holes in the concave stator cores 20 and 22.
Since the positioning of the coil 2 and the coil bobbin 30 is performed by the guide 38, the diameter of the hole may be larger than the diameter of the protrusion.

Further, in the above embodiment, the guide 38 for correcting the positional deviation is formed on the coil bobbin 30 corresponding to all the magnetic poles 20b or 22b of the concave stator cores 20, 22. That is, 8 magnetic poles 2
16 guides 38 to the body 3 with respect to 0b (22b).
3 is formed on the inner side wall.

However, the guide 38 can position the concave stator cores 20 and 22 and the coil bobbin 30 as long as at least the same magnetic pole 20b or 22b is formed in one set (two sets). This is preferable because the weight of the coil bobbin 30 can be reduced.

Further, in the above embodiment, the magnetic pole housing portion 39 is formed on the inner peripheral surface of the body portion 33 by being divided by the two guides 38.
It is also possible to connect the radially inner end faces of the above and to use the space formed between the connecting face and the inner peripheral surface of the body portion 33 as the magnetic pole accommodating portion 39.

With the above construction, when the coil bobbin 30 and the concave stator cores 20 and 22 are inserted while being displaced, when the magnetic poles 20b and 22b move along the guide 38, the magnetic poles 20b and 22b move from the guide 38 to the radial direction. It is preferable because it does not come off inward in the direction.

[0065]

As described above, according to the stepping motor of the present invention, the stator core and the coil bobbin, which are the component parts thereof, are arranged such that the magnetic poles of the stator core are inserted into the coil bobbin at predetermined positions during assembly. Since it is equipped with a structure that fits while the position of the stepping motor is corrected, it provides a stable quality stepping motor that is unlikely to cause positional deviation between the stator core and the coil bobbin, which is the cause of abnormal stepping motor characteristics, vibration, and noise. can do.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a stepping motor according to an embodiment.

FIG. 2 is a front view (A) and A- of a stator core according to an embodiment.
It is an A line sectional view (B).

FIG. 3 is a front view (A) and B- of the coil bobbin of the embodiment.
It is a B line sectional view (B).

FIG. 4 is a partially enlarged view of a coil bobbin of another embodiment.

FIG. 5 is a front view (A) and X- of a conventional coil bobbin.
It is an X-ray sectional view (B).

FIG. 6 is a front view (A) and Y- of a conventional stator core.
It is a Y-line sectional view (B).

[Explanation of symbols]

11 Upper Housing, 11a Hole, 12 Lower Housing, 12a Extension, 12b Recess, 12d
Positioning protrusion, 12e cutout portion, 12f protrusion, 12h rib, 13 plate, 13a protruding shaft, 13b boss portion, 13c protruding shaft, 20 concave stator core, 20a stator yoke portion, 20b
Magnetic pole, 20d notch, 20e housing wall, 22
Stator core, 22a Stator yoke part, 22b
Magnetic pole, 22c positioning hole, 22d notch,
30 coil bobbin, 30a winding, 31, 32
Side plate, 33 body part, 34 terminal mounting part, 3
4a Fitting hole, 34b Fitting projection, 35 Terminal, 36, 37 Positioning projection, 38 Guide,
39 magnetic pole accommodation part, 40 rotor, 40a rotor body, 40b rotor shaft, 40c gear part, 50
Reduction gear, 51 outer gear, 52 internal gear, 53 washer, A, B stator, M
Stepping motor

Claims (4)

[Claims] 1. A stepping motor including a stator having a coil bobbin disposed between two stator cores, wherein the coil bobbin coaxially connects a pair of side plates having a central hole and a central hole of the pair of side plates. And a terminal mounting portion formed on one side plate, and a winding. The stator core includes a stator yoke portion having a central hole, and an axial direction from a central hole edge portion of the stator yoke portion. A stepping motor, wherein at least one magnetic pole accommodating portion having substantially the same shape as the magnetic pole is formed on the inner surface of the body of the coil bobbin. . 2. The stepping motor according to claim 1, wherein the magnetic pole housing portion is formed by a ridge formed on an inner surface of a body portion of the coil bobbin. 3. The inner surface of the body of the coil bobbin includes:
The stepping motor according to claim 1 or 2, wherein the number of the magnetic pole housing portions is equal to the number of magnetic poles of the two stator cores. 4. The stator is coaxially laminated, and at least a side plate or a terminal mounting portion of the coil bobbin is formed with a positioning protrusion and a hole for engaging with a side plate or a terminal mounting portion of the coil bobbin which faces the coil bobbin. The stepping motor according to claim 1, wherein the stepping motor is a motor.