JPH06284675A - Stepping motor - Google Patents

Abstract

PURPOSE:To provide a stepping motor which is provided with a relatively large space and can be constituted in a thin type with high accuracy. CONSTITUTION:This stepping motor 10 is so constituted of a rotor 13 as to include at least one pair of flat annular pole tooth yokes 12a, 12b, 12c, 12d with pole teeth extending toward the inside thereof, annular plane coils 17, 18 respectively provided between each pair of tooth yokes and flat plate-like magnets provided at the center of the pole tooth yokes and magnetized with multi-polarities in the circumferential direction.

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 the structure of a thin stepping motor.

[0002]

2. Description of the Related Art Conventionally, such a stepping motor is constructed, for example, as shown in FIG. In the figure, a stepping motor 1 is supported and arranged annularly so as to be rotatable in a hollow pole tooth assembly 3 disposed around a case 2 and a hollow portion of the pole tooth assembly 3. And a rotor 4 having a magnet 4a. Here, in the rotor 4, the rotation shaft 5 is
It is rotatably supported by a bearing 6 fixed to the case 2.

Here, the pole tooth assembly 3 has four pole tooth yokes 3 which are arranged so as to face each other two by two.
A bobbin including a winding portion of the coil 7 is integrally formed by resin-molding a, 3b, 3c, 3d by insert molding or the like. As a result, the winding portions 8a and 8b where the two windings are to be wound are formed.

The pole tooth yokes are formed as shown in FIG. 7, for example. That is, in FIG. 7, the pole tooth yoke 9 includes an annular flange portion 9a, and a plurality of pole teeth yokes 9a protruding from the flange portion 9a at equal angular intervals so as to stand upright in the figure, and four poles in the illustrated case. It has teeth 9b.

According to the stepping motor 1 thus constructed, each coil 7 wound around the winding portions 8a and 8b is
, By energizing in a predetermined direction and order,
A magnetic pole is generated in each pole tooth of each pole tooth yoke, and the rotor 4 is rotationally driven by the action of the magnetic field.

[0006]

However, in the stepping motor 1 thus constructed, the pole tooth yoke 9 is formed by bending or deep drawing the pole teeth 9b. For this reason, when the stepping motor is miniaturized, the machining accuracy of the pole teeth is limited, and a material such as a silicon steel plate with a small iron loss cannot be used because it is difficult to perform a sharp bending process. There was a problem.

Further, the winding portion 8a of the pole tooth assembly 3,
8b is formed by a bobbin integrally formed with the pole tooth yokes 3a, 3b, 3c, 3d. Therefore, the winding portion 8
Since a and 8b become relatively small, the coil space becomes small. Further, when the size is reduced, it is difficult to wind the coils in a line, and there is a problem that the ratio of the portion that does not contribute to the characteristics is increased.

In view of the above points, the present invention has an object to provide a stepping motor which has a relatively large coil space and is configured to be thin and highly accurate.

[0009]

According to the present invention, there is provided at least a pair of flat annular pole tooth yokes having inwardly extending pole teeth, and between the pair of pole tooth yokes. This is achieved by a stepping motor that includes an annular coil that is disposed and a rotor that is disposed in the center of the pole tooth yoke and that is composed of a magnet that is magnetized in the circumferential direction with multiple poles.

In the stepping motor according to the present invention, preferably, the coil is a plane coil and is an aligned winding coil, a laminated coil or a sheet coil.

In the stepping motor according to the present invention, preferably, the pole tooth yoke is formed by punching a silicon steel plate.

Further, in the stepping motor according to the present invention, preferably, a pattern coil for position detection is formed on the surface of the pole tooth yoke.

Further, in the stepping motor according to the present invention, preferably, the pole tooth yoke and the coil are sequentially fitted and inserted into a cylindrical positioning jig to be positioned and assembled with each other.

[0014]

According to the above structure, since the pole tooth yoke is flat, it is formed by punching or the like.
Therefore, complicated processes such as bending and deep drawing are unnecessary, and the process is easily performed. Further, since the coil disposed between the pole tooth yokes is an annular coil, the pole tooth assembly is thin, and the stepping motor as a whole is thin.

When the coil is a plane coil,
The pole tooth assembly is made even thinner. Further, in the case of an aligned winding coil, a laminated coil or a sheet coil, the number of turns of the coil increases in the same coil space.

When the pole tooth yoke is formed by punching a silicon steel plate, iron loss during operation of the stepping motor is reduced.

When a pattern coil for position detection is formed on the surface of the pole tooth yoke, this pattern coil is formed at the same time as another pattern, so that the position detection coil can be easily formed. Will be obtained.

Further, when the pole tooth yoke and the coil are positioned and assembled with each other by sequentially inserting the pole tooth yoke and the coil into the cylindrical positioning jig, they can be easily assembled with each other. And it can be done accurately.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to FIGS. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows an embodiment of a stepping motor according to the present invention. In FIG. 1, a stepping motor 10 has a hollow pole tooth assembly 12 arranged around a flat case 11, and a stepping motor 10 that is supported and has an annular shape so as to be rotatable in the hollow portion of the pole tooth assembly 12. Rotor 13 with magnet 13a arranged
It consists of and.

Here, the rotor 13 has its rotating shaft 14
Is rotatably supported by a flange 15 that closes the case 11 from above and below, and bearing portions 15a and 16a provided on the bottom plate 16.

In the present embodiment, the pole tooth assembly 12 has four pole tooth yokes 12a, 12b, 12c and 12d arranged so as to face each other two by two.
And pole tooth yokes 12a and 12b which are paired with each other.
In between, the plane coil 17 and the pole tooth yokes 12c, 1
The plane coil 18 is arranged between 2d.

Of the above pole tooth yokes, the pole tooth yoke 12
Each of a and 12d is punched by forming an insulating layer on the surface of a silicon steel plate and pressing. Similarly, the pole tooth yokes 12b and 12c are formed by providing an insulating layer on the surface of a silicon steel sheet, providing a copper pattern on the insulating layer, and then punching by press working.

As shown in FIG. 2, the plane coils 17 and 18 are, for example, tapless coils which are preliminarily aligned and wound, and the pole tooth yokes 12b and 12b are formed by high frequency heating using cream solder. The terminal portion 2 is soldered to the land portions 19 and 20 of the copper pattern 12c.
1, 22 are drawn out.

For example, by peeling off the coil insulation at two points 18a and 18b inside and outside the upper surface of the planar coil 18, these portions 18a and 18b are soldered to the land portion on the lower surface of the pole tooth yoke 12c. Attached.

At the same time, the pole tooth yokes 12a, 12
d is also soldered for positioning. this is,
For example, three places 17a, 1 around the upper surface of the plane coil 17
7b, 17c and the lower surface of the plane coil 18 at three locations around the lower surface of the plane coil 18 by peeling off the coil insulation.
a positioning pattern (not shown) and pole tooth yoke 1
This is performed by joining with the positioning patterns 23, 24, 25 of 2d. The plane coils 17 and 1 are
8 can be formed by a laminated coil or a sheet coil.

The rotor 13 has a magnet 13a.
However, so that S poles and N poles are alternately arranged in the circumferential direction,
It is magnetized in multiple poles, for example, 12 poles.

Stepping motor 10 according to this embodiment
Is performed by using the positioning jig 30 shown in FIG. 3 when assembling the pole tooth assembly 12. That is, in FIG. 3, the positioning jig 30 is
The pole tooth yokes 12a, 12b, 12c, 12d and the plane coils 17, 18 are arranged so that the cylindrical engaging portion 31 that is sequentially inserted and the protruding portion 40 of each pole tooth yoke can be sandwiched. It is composed of two positioning pins 32 (see FIG. 2).

The positioning jig 30 configured as described above
On the other hand, the pole tooth yoke 12d, the plane coil 18, the pole tooth yoke 12c, the pole tooth yoke 12B, the plane coil 17, and the pole tooth yoke 12a are sequentially fitted and inserted. At this time, cream solder is applied to each land to be soldered. When the flat coils 17 and 18 are fitted and inserted, the inner peripheral portions of the flat coils 17 and 18 are
Accurate centering can be performed by inserting the sleeve.

As a result, the inner circumference and the outer circumference of each pole tooth yoke and the plane coil do not contact the rotor 13 and the case 11 when completed. In particular, since the planar coils 17 and 18 can maintain a sufficient clearance with respect to the rotor 13 and the case 11, it is not necessary to form an insulating layer.

Finally, the cream solder can be melted by high-frequency heating, and soldering can be performed at each land portion or the like. Thus, the pole tooth assembly 12 is completed.

Then, a case 11 made of a silicon steel plate or an iron plate is mounted around the pole tooth assembly 12, and a resin flange 15 and a bottom plate 16 are press-fitted from above and below to complete the stepping motor 10.

In the above embodiment, the pole tooth yokes 12a, 12b, 12c, 12d are formed by punching a flat disk to form pole teeth extending inward. As shown in FIG. 4, the flat coil 1 is formed by forging after punching a thin silicon steel plate.
By forming the recessed portion to receive 7 and 18, the coil space of each pole tooth yoke 12a, 12b, 12c and 12d increases. As a result, when the same planar coils 17 and 18 are used, the pole tooth assembly 12 and the stepping motor 10 are made thinner.

Further, on the surface of the pole tooth yoke 12d, as shown in FIG.
As shown in (A), the pattern coil 12e may be formed. In this case, this pattern coil 12e
Is connected as shown in FIG.
It will act as a coil for position detection.

As described above, in the stepping motor of this embodiment, since the pole tooth yoke is flat,
It is formed by punching or the like. Therefore, complicated processes such as bending and deep drawing are not required, and the process can be easily and highly accurately performed.

Since the pole tooth assembly is constructed by stacking the pole tooth yoke and the plane coil,
Since there is no insulating layer, the coil space becomes relatively large. Therefore, the number of turns of the coil is increased and the torque is increased. Further, since the coil arranged between the pole tooth yokes is a plane coil, the coil space is effectively used and a relatively high torque can be obtained.

When the plane coil is an aligned winding coil, a laminated coil or a sheet coil, the number of turns of the coil increases in the same coil space. Therefore,
The torque can be further increased. When the pole tooth yoke is formed by punching a silicon steel plate, iron loss during operation of the stepping motor is reduced. Therefore, a low-loss stepping motor can be obtained.

When a pattern coil for position detection is formed on the surface of one pole tooth yoke, this pattern coil is formed at the same time as other patterns, so that the number of parts does not increase. Further, the position detecting coil can be easily obtained at low cost without increasing the number of steps.

Further, when the pole tooth yoke and the plane coil are positioned and assembled with each other by sequentially inserting the pole tooth yoke and the plane coil into a cylindrical positioning jig, they can be easily assembled with each other. Since it can be performed accurately and accurately, for example, the planar coil can maintain sufficient clearance with respect to the rotor at the inner peripheral portion and to the case at the outer peripheral portion. Therefore, this planar coil does not need to be insulated on its inner and outer circumferences. Thus, the cost will be reduced.

[0040]

As described above, according to the present invention, it is possible to provide a stepping motor in which the coil space can be increased and which is configured to be thin and highly accurate.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a stepping motor according to the present invention.

2 is an exploded perspective view of a pole tooth assembly of the stepping motor of FIG. 1. FIG.

3 (A) is a plan view and FIG. 3 (B) is a cross-sectional view of a positioning jig used when assembling the pole tooth assembly of FIG.

FIG. 4 is a partial cross-sectional view showing another configuration example of the pole tooth yoke.

5 (A) is a plan view and FIG. 5 (B) is a circuit diagram showing an electrical configuration of a pole tooth yoke provided with a pattern coil for position detection.

FIG. 6 is a sectional view showing an example of a conventional stepping motor.

7 is a perspective view of a pole tooth yoke used in the stepping motor of FIG.

[Explanation of symbols]

 10 stepping motor 11 case 12 pole tooth assembly 12a pole tooth yoke 12b pole tooth yoke 12c pole tooth yoke 12d pole tooth yoke 13 rotor 14 rotary shaft 15 flange 16 bottom plate 17 plane coil 18 plane coil 19 land portion 20 land portion 21 terminal portion 22 Terminal part 23 Positioning pattern 24 Positioning pattern 25 Positioning pattern

Claims (7)

[Claims] 1. At least a pair of flat annular pole tooth yokes having inwardly extending pole teeth, an annular coil disposed between the pair of pole tooth yokes, and a pole tooth yoke of the pole tooth yoke. A stepping motor, comprising: a rotor that is arranged in the center and is composed of a magnet that is magnetized in multiple poles in the circumferential direction. 2. The stepping motor according to claim 1, wherein the coil is a plane coil and an aligned winding coil. 3. The stepping motor according to claim 1, wherein the coil is a plane coil and a laminated coil. 4. The stepping motor according to claim 1, wherein the coil is a plane coil and a sheet coil. 5. The stepping motor according to claim 1, wherein the pole tooth yoke is formed by stamping a silicon steel plate. 6. The stepping motor according to claim 1, wherein a pattern coil for position detection is formed on the surface of the pole tooth yoke. 7. The pole tooth yoke and the coil are positioned and assembled with each other by sequentially inserting and fitting them into a cylindrical positioning jig.
The stepping motor according to claim 1.