JPH0837770A - Two-phase motor - Google Patents

Abstract

PURPOSE:To provide a two-phase motor which can be assembled easily thanks to a simple constitution and in which the space factor of a coil is enhanced. CONSTITUTION:A two-phase motor 10 is provided with a pole-teeth assembly which is composed of two sets of pole-teeth yokes 21, with an air-core coil 23 which is housed inside the ring hollow part of the pole-teeth assembly and with a rotor 14 which is provided with a magnet 14a which is supported to be rotatable to face pole teeth of the pole-teeth assembly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-phase motor, and more particularly to a two-phase motor used as a stepping motor or the like.

[0002]

2. Description of the Related Art Conventionally, a two-phase stepping motor is constructed, for example, as shown in FIG. In FIG.
The two-phase stepping motor 1 is supported in a hollow pole tooth assembly 3 arranged around the inside of the case 2, and is supported in a hollow portion of the pole tooth assembly 3 and is supported in an annular multipole manner. And a rotor 4 having a magnetized rotary magnet. The rotation shaft 5 of the rotor 4 is rotatably supported by a bearing 6 fixed to the case 2.

Here, the pole tooth assembly 3 is formed by resin molding by insert molding or the like with respect to four pole tooth yokes, which are arranged so as to face each other two by two. A bobbin having the above is integrally formed. As a result, the winding portions 8a and 8b on which the two windings are to be wound are defined. At this time, the pair of upper pole tooth yokes and the pair of lower pole tooth yokes have a phase of 90 degrees.
It is arranged so as to be offset. Therefore, the winding portion 8a,
The coils 7 wound around 8b are offset by 90 degrees from each other and face the magnets forming the rotor 4 as the A phase and the B phase, respectively.

According to the two-phase stepping motor 1 thus constructed, each coil 7 wound around the winding portions 8a and 8b is energized in a predetermined direction and in order so that each pole A magnetic pole is generated at each pole tooth of the tooth yoke, and the rotor 4 is driven to rotate.

[0005]

However, in the stepping motor 1 having such a structure, as shown in FIG.
As shown in, the coil 7 is wound around the winding portion of the bobbin insert-molded with the pole tooth yoke. Therefore, since the space factor of the coil 7 with respect to the pole tooth yoke is relatively low, there is a problem that a very large torque cannot be obtained.

Further, since the coil 7 is wound by winding a winding wire around a bobbin insert-molded for each pole tooth yoke of the pole tooth assembly 3, the process is complicated, As the cost increases,
There was a problem of poor workability.

In view of the above points, the present invention has as its object the provision of a two-phase motor which is easily assembled with a simple structure and which has an improved coil space factor.

[0008]

According to the present invention, there is provided a pole tooth assembly comprising two sets of pole tooth yokes,
A two-phase motor including an air-core coil coil housed in the annular hollow portion of the pole tooth assembly and a rotor including a magnet rotatably supported so as to face the pole teeth of the pole tooth assembly. Is achieved.

The two-phase motor according to the invention is preferably
A pole tooth assembly has a cup-shaped first pole tooth yoke having an annular groove whose one end in the axial direction is open, and a second pole formed so as to close the open end of the first pole tooth yoke. It consists of a tooth yoke.

The two-phase motor according to the invention is preferably
The first and second pole tooth yokes include pole teeth extending so as to be alternately engageable in the circumferential direction.

The two-phase motor according to the invention is preferably
The first pole tooth yokes of the two sets of pole tooth assemblies are welded back to back.

The two-phase motor according to the invention is preferably
The first and second pole tooth yokes are fixed to each other by crimping.

[0013]

According to the above construction, the stator is constructed by accommodating the air-core coil in the annular hollow portion of the pole tooth assembly. As a result, the coil is arranged without the need for the bobbin, so that the space can be effectively used accordingly.

A pole tooth assembly is formed so as to close a cup-shaped first pole tooth yoke having an annular groove whose one end in the axial direction is open, and an open end portion of the first pole tooth yoke. If it is composed of two pole tooth yokes, each pole tooth yoke is easily formed.

When the first and second pole tooth yokes are provided with pole teeth extending so as to be alternately engageable with each other in the circumferential direction, the pole tooth yokes are formed by a simple structure. It will be.

When the first pole tooth yokes of the two sets of pole tooth assemblies are welded back-to-back with each other, the pole tooth assemblies of each set are easily and securely fixed to each other.

When the first and second pole tooth yokes are fixed to each other by crimping, the second pole tooth yoke can be easily assembled to the first pole tooth yoke.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to FIGS. In addition, since the Examples described below are preferred specific examples of the present invention, various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated.

1 and 2 show an embodiment of an inner rotor type PM stepping motor used as a spindle motor to which the present invention is applied. In the figure, a housing 12 is mounted on a substrate 11. An annular pole tooth assembly 13 is arranged around the housing 12. This pole tooth assembly 1
In the hollow portion of No. 3, a rotor 14 provided with a rotary magnet 14a that is magnetized in multiple rings in an annular shape is supported so as to be rotatable in the hollow portion so as to face the pole tooth assembly 13 from above in the illustrated case. It is placed in a closed state.

Here, the rotor 14 has its rotating shaft 1
4b is rotatably supported by a bearing portion 12a provided at the center of the housing 12, and the substrate 1
1 is in point contact with the thrust bearing 11a fixed on the surface 1 by adhesion or the like.

The pole tooth assembly 13 is constructed by incorporating coils into the two-phase pole tooth yokes.

The pole tooth yoke of each phase is, as shown in FIG.
A cup-shaped first pole tooth yoke 21 having an annular groove whose one end in the axial direction is open, and a second pole formed so as to close the open end portion of the first pole tooth yoke 21. It is composed of a tooth yoke 22. Then, as shown in FIG. 3, the coil 23 is housed in an annular hollow portion defined by the first pole tooth yoke 21 and the second pole tooth yoke 22.

Specifically, the first pole tooth yoke 21 is provided.
Are formed as shown in FIGS. 4 and 5. That is,
In FIG. 4 and FIG. 5, the first pole tooth yoke 21 has an annular groove 21a whose one axial end (lower end in FIG. 5) is open.
Is formed in a cup shape so as to have a plurality of pole teeth 21b, which in the case of FIG. Further, as shown in FIG. 3, the first pole tooth yoke 21 is provided with a cutout portion 21c between the pole teeth 21b.

On the other hand, the second pole tooth yoke 22 is
It is formed as an annular flat plate ring so as to close the open end portion of the first pole tooth yoke 21, and is provided with a plurality of pole teeth 22a rising from a plurality of positions on the inner edge portion thereof. A notch 22b is provided between each pole tooth 22a.
It has. The pole teeth 22a are arranged so that when the first and second pole tooth yokes 21 and 22 are combined, they can alternately engage with the pole teeth 21b of the first pole tooth yoke 21. . Further, the second pole tooth yoke 22 is provided with a claw portion 22c protruding outward from the outer edge thereof.

Further, as shown in FIGS. 2 and 3, two first pole tooth yokes 21 are vertically arranged and welded to each other back to back, and the groove 2 of each first pole tooth yoke 21 is formed.
Air core coils 23 are housed in the respective 1a and are fixed by, for example, double-sided tape or the like. Then, the second pole tooth yoke 22 is assembled to the first pole tooth yoke 21 so as to close the open end portion of the first pole tooth yoke 21.

At this time, in FIG. 2, the pair of upper pole tooth yokes and the pair of lower pole tooth yokes are arranged so as to be out of phase with each other by 90 degrees. As a result, a two-phase yoke is constructed.

Each coil 23 is connected to a conductive pattern formed on the board 11 via a flexible printed board 24, and power is appropriately supplied via a control circuit 15 mounted on the board 11. I'm supposed to get it.

Stepping motor 10 according to this embodiment
Is configured as described above, and by energizing each coil 23 in a predetermined direction and order via the control circuit 15, each pole tooth 21 of each pole tooth yoke 21 and 22 is supplied.
Magnetic poles are generated at b and 22a, and the rotor 14 is driven to rotate.

In this case, each coil 23 is housed in an annular hollow portion defined by the first pole tooth yoke 21 and the second pole tooth yoke 22, and at the same time, the first pole tooth yoke 21. In the second pole tooth yoke 22, the pole teeth 21b and 22a of the second pole tooth yoke 22 are the other notches 21c and 22b.
Since the coil 23 is fixed and held by being crimped inside, no stress acts on the coil 23.

Therefore, the coil 23 can almost completely occupy the annular hollow portion defined by the first pole tooth yoke 21 and the second pole tooth yoke 22. The space factor of the coil 23 with respect to the hollow portion of 22 is improved. Therefore, a larger torque can be obtained by the pole tooth yoke having the same size.

Here, the notch 2 of the second pole tooth yoke 22
2b is used as a relief when soldering the flexible printed circuit board 24 to the end of the coil 23,
The workability of soldering the flexible printed circuit board 24 is improved.

The claw portion 22c protruding outward from the outer edge of the second pole tooth yoke 22 is used when the housing 12 or the substrate 11 is crimped.

As described above, in this embodiment, the air-core coil is housed in the annular hollow portion defined by the first pole tooth yoke and the second pole tooth yoke which constitute the pole tooth assembly. A stator is constituted by. Therefore,
Since the bobbin for winding the coil does not exist in the hollow portion of the pole tooth assembly, the space factor of the coil with respect to the hollow portion of the pole tooth assembly is improved. Thus,
The torque will be increased.

The pole tooth assembly is formed so as to close the cup-shaped first pole tooth yoke having an annular groove whose one end in the axial direction is open, and the open end portion of the first pole tooth yoke. If it is composed of two pole tooth yokes, each pole tooth yoke is easily formed. Therefore, the cost of the pole tooth yoke is reduced.

When the first and second pole tooth yokes are provided with pole teeth extending so as to be alternately engageable with each other in the circumferential direction, the pole tooth yokes are formed by a simple structure. It will be. Therefore, the cost of the pole tooth yoke is reduced. When the first pole tooth yokes of the two sets of pole tooth assemblies are welded back-to-back to each other, the pole tooth assemblies of each set are easily and securely fixed to each other. Therefore, the mutual strength of the pole tooth assemblies of each set can be increased.

When the first and second pole tooth yokes are fixed to each other by crimping, the second pole tooth yoke can be easily assembled to the first pole tooth yoke.
Therefore, the workability of assembly is improved.

In the above embodiment, the case of the inner rotor type PM stepping motor 10 used as a spindle motor has been described, but the present invention is not limited to this, and the present invention can be applied to other types of two-phase motors. Obviously, can be applied.

[0038]

As described above, according to the present invention, it is possible to provide a two-phase motor which can be easily assembled with a simple structure and which has an improved coil space factor. .

[Brief description of drawings]

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

FIG. 2 is a schematic sectional view of the stepping motor of FIG.

FIG. 3 is a partially cutaway perspective view of a pole tooth assembly in the stepping motor of FIG.

4 is a plan view of a first pole tooth yoke in the stepping motor of FIG. 1. FIG.

5 is a sectional view of the first pole tooth yoke of FIG. 4 taken along line XX.

FIG. 6 is a schematic sectional view showing an example of a conventional two-phase stepping motor.

[Explanation of symbols]

 10 stepping motor 11 substrate 12 housing 12a bearing portion 13 pole tooth assembly 14 rotor 14a rotary magnet 14b rotating shaft 15 control circuit 21 pole tooth yoke 21a annular groove 21b pole tooth 21c notch 22 pole tooth yoke 22a pole tooth 22b notch 22c Part 23 Air core coil

Claims (5)

[Claims] 1. A pole tooth assembly including two pairs of pole tooth yokes, an air-core coil coil housed in an annular hollow portion of the pole tooth assembly, and a rotary tooth assembly so as to face the pole teeth of the pole tooth assembly. A two-phase motor comprising a rotor provided with a magnet supported so as to be possible. 2. The pole tooth assembly is formed so as to close a cup-shaped first pole tooth yoke having an annular groove whose one end in the axial direction is open, and an open end portion of the first pole tooth yoke. 2. The two-phase motor according to claim 1, further comprising: 3. The two-phase according to claim 2, wherein the first and second pole tooth yokes have pole teeth extending so as to be alternately engageable with each other in the circumferential direction. motor. 4. The two-phase motor according to claim 2, wherein the first pole tooth yokes of the two sets of pole tooth assemblies are welded back to back. 5. The two-phase motor according to claim 2, wherein the first and second pole tooth yokes are fixed to each other by crimping.