JPH0984282A - Stator for motor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stator for a motor, and a manufacturing method thereof, in which the space factor of the exciting coil (density of winding) can be enhanced while reducing the magnetic loss. SOLUTION: The stator 4 for a motor 2 comprises a stator core 10 provided with eight pole teeth 8 with a constant interval in the inner circumferential surface thereof, and an exciting coil 12 fitted to each the pole tooth 8, wherein the stator core 10 comprises a core block 18 split into a uniform shape for each pole tooth 8, and a steel pipe 20 shrink fitted with the core block 18. Since the split faces 19a, 19b of the core block 18 shrink fitted to the steel pipe 20 are pressed strongly each other, magnetic loss is reduced at the split faces 19a, 19b. Furthermore, since the exciting coil 12 can be wound under a state where the core block 18 is split, the exciting coil 12 can be shaped arbitrarily and the space between the exciting coils 12 can be reduced extremely in the stator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of an electric motor used in various industrial equipment.

[0002]

2. Description of the Related Art Conventionally, for example, in a stepping motor, as shown in FIG. 2 (A), a plurality of pole teeth H serving as magnetic poles are arranged at equal intervals along the circumferential direction of the inner peripheral surface in the central axis direction. The stator (stator) S is composed of a cylindrical stator core (stator core) SC projecting toward and the exciting windings (excitation coils) CL wound around the respective pole teeth H.
1 is configured, and a rotor (rotor) (not shown) is rotatably arranged inside the stator S1. Note that FIG. 2A shows a plan sectional view of the stator S.

Here, in the conventional stepping motor, when the stator S1 is manufactured, as shown by the dotted line in FIG. 2 (A), the same ring-shaped excitation winding can be fitted to each pole tooth H, respectively. The wire CL is preformed separately from the stator core SC, and the exciting winding CL is fitted into each pole tooth H as shown by the arrow in FIG. 2 (A). There is. The excitation winding CL is obtained by directly winding an enamel wire (copper wire coated with enamel) around the pole tooth H.
However, this method cannot be used unless the dimension between the pole teeth H is relatively large.

However, in the conventional motor described above, as shown by the hatched portion K in FIG. 2B, the space between the excitation windings CL fitted in the adjacent pole teeth H becomes large, and the excitation windings are increased. The winding density of the line CL (that is, the space factor of the exciting winding CL) cannot be increased, and the output (torque) of the motor cannot be improved.

To solve this problem, for example,
In JP-A-7-7875, as shown in FIG. 3A, a core block CB divided for each pole tooth H is connected in an annular shape, and the connecting portion is welded M to be fixed. A fixed stator S2 is disclosed.

In this stator S2, as shown in FIG. 3 (B), the exciting winding CL can be wound around the pole teeth H for each core block CB in advance before connecting the core blocks CB. The shape of the excitation winding CL can be arbitrarily formed. Therefore, here, the shape of the excitation winding CL is substantially fan-shaped so that the cross-sectional shape in the direction orthogonal to the axial direction of the stator S2 is larger on the yoke side than on the tip side of the pole tooth H. For example, when the stator S2 is assembled by connecting the core blocks CB, the space K shown in FIG.
Since it is occupied by L, the space factor of the excitation winding CL can be increased.

On the other hand, as shown in FIG. 4 (A), on the other hand, an inner core CI formed in a shape in which each pole tooth H is connected at an end of the stator core SC on the center side, and a cylindrical shape. There is known a stator S3 which is formed of a core and an outer core CO for forming a yoke around the inner core CI and is assembled by shrinking the inner core CI into the outer core CO.

In this stator S3, as shown in FIG. 4 (B), the excitation winding CL is wound around each pole tooth H before the inner core CI is shrink-filled in the outer core CO. ,
The distance between the pole teeth H is wider at the ends that are not connected to each other. Therefore, the ring-shaped excitation winding CL that can be fitted into the pole tooth H is formed in advance, and the cross-sectional shape of the stator S3 in the direction orthogonal to the axial direction has a cross-sectional shape that is closer to the end portion where the pole tooth H is connected. 2B, the space on the open end side is larger than the size shown in FIG. 2B, and by forming the excitation winding CL into each pole tooth H, the space K shown in FIG. Since it is occupied by the line CL, the space factor of the excitation winding CL can be increased.

[0009]

However, in the case of the former stator S2, the welding causes welding to increase the magnetic loss in the stator S2 and, in turn, the motor formed by this stator S2. There was a problem of deteriorating the output of.

That is, as shown in FIG. 5, the stator core SC
Are usually in the range of 0.35 to 0. to prevent eddy currents.
It is composed of a laminated iron core formed by laminating silicon steel plates B each having a thickness of about 5 mm and having an insulating layer formed on the surface thereof. However, in the stator S2, an eddy current flows in the welded portion M. However, the magnetic loss will increase.

Not only that, but in this stator S2, the vicinity of the welded portion M is in a so-called annealed state due to heating during welding, the magnetic permeability changes and magnetic distortion occurs, and the magnetic path is formed. Since it is disturbed, this also increases the magnetic loss, and further, the divided surfaces of the core blocks CB which are connected to each other by welding have low adhesion, and in some cases, a gap E is generated as shown in the figure. In some cases, as a result, the magnetic resistance on the split surface increases, which also increases the magnetic loss.

On the other hand, in the case of the latter stator S3, the pole teeth H
However, since they are connected to each other at the end portion on the side facing the rotor (not shown), there is a problem that magnetic flux leakage occurs between the pole teeth H, resulting in deterioration of the output of the motor. In addition, when the outer core CO and the inner core CI are composed of laminated iron cores, in all the pole teeth H in the work of shrink-fitting, which must be performed quickly,
It is difficult to match the layers of the laminated silicon steel plates, and if the layers of the steel plates are deviated between the outer core CO and the inner core CI, the magnetic path is disturbed and the magnetic loss increases. .

In order to solve the above problems, the present invention provides
It is an object of the present invention to provide a stator of an electric motor that can improve the space factor of the excitation winding and has a small magnetic loss, and a method for manufacturing the stator.

[0014]

In order to achieve the above object, the invention according to claim 1 is formed in a cylindrical shape, and at equal intervals along the circumferential direction of its inner peripheral surface, A stator of an electric motor, comprising: a stator core having a plurality of pole teeth serving as magnetic poles projecting in the direction of the central axis; and an excitation winding wound around each of the pole teeth. The child core has a split core formed by dividing the stator core for each pole tooth, and an annular shape that presses the split core that is cylindrically connected from the outer peripheral side to maintain the connected state of the split core. And a fixing member.

In the stator of the electric motor according to the present invention having the above-mentioned structure, the fixing member presses the split cores, which are connected in a cylindrical shape, from the outer peripheral side of the split cores to maintain the connection state of the split cores. To do. At this time, the split surfaces of the split core are pressed in a direction in which they are in close contact with each other.

That is, since all the split surfaces of the split core are in close contact with each other, the magnetic resistance on the split surfaces is reduced,
Moreover, since no solder is applied to the split surface, no eddy current will flow on the split surface. Therefore, according to the stator of the electric motor of the present invention, since the magnetic loss is small, the magnetic flux can be efficiently generated, and by using the stator, an efficient electric motor can be obtained. .

Further, according to the present invention, since the stator core is formed by connecting the split cores, the exciting windings are previously attached to the pole teeth of each split core before the split cores are connected. Can be wrapped. As a result, not only the workability of winding the exciting winding is improved, but also the exciting winding can be formed in an arbitrary shape, so that the space factor of the exciting winding can be increased, and The output of the electric motor using the stator can be improved.

Further, according to the present invention, since the stator core is composed of the split cores, the pressing device for manufacturing the split cores is smaller than that for manufacturing the integrally formed stator core. The base material pressed by the pressing device can be downsized. Moreover, since the split core has a relatively simple shape, the base material can be effectively used.

Next, the invention described in claim 2 is
In the stator of the electric motor described in the paragraph 1, the fixing member is made of a steel pipe that shrink-fits the split cores connected in a cylindrical shape. Claim 2 constituted in this way
According to the stator of the electric motor described in (1), the split cores connected in a cylindrical shape can be easily and strongly pressed and held,
The magnetic loss on the split surface of the split core can be reduced more reliably.

In the present invention, unlike the outer core CO of the conventional device shown in FIG. 4, the fixing member is not for forming a magnetic path, so that it is not necessary to form a laminated core, The simple steel pipe of can be used. Next, the invention described in claim 3 is the same as claim 1
Alternatively, in the stator of the electric motor according to claim 2, concave portions and convex portions that are fitted to each other when the divided cores are connected in a cylindrical shape are formed on each divided surface of the divided core. Is characterized by.

According to the stator of the electric motor of the third aspect, the contact area between the split cores is large, so that the magnetic resistance on the split surfaces is small, that is, the magnetic loss on the split surfaces. Can be further reduced. Further, when the split cores are connected to each other in a cylindrical shape, the split cores can be easily formed into a connection shape by fitting the recesses and the projections formed on each split surface to each other. Workability can be improved.

Next, a fourth aspect of the present invention is directed to the first aspect.
The stator of the electric motor according to any one of claims 1 to 3 is characterized in that a magnetically permeable adhesive is applied to the split surface of the split core.

According to the stator of the electric motor according to the fourth aspect of the present invention thus constructed, for example, the manufacturing accuracy of the split core is poor, or the split surface of the split core is lacking for some reason. Even if a gap is created between the split surfaces when the cores are connected, since the gap is filled with the magnetically permeable adhesive, the magnetic loss on the split surface is not significantly deteriorated and the reliability of the stator is improved. Can be improved.

When connecting the split cores into a cylindrical shape,
Even before attaching the fixing member, the connected shape can be maintained, and the workability of the stator assembly can be further improved. As the magnetically permeable adhesive, for example, an adhesive in which powder of magnetic material such as ferrite is mixed can be used. In particular, it is desirable to use a magnetic material having a high electric resistance as much as possible so that an eddy current does not flow in the portion coated with the adhesive.

On the other hand, the invention described in claim 5 is the same as claim 2.
A manufacturing method for manufacturing the stator of the electric motor according to, wherein the divided cores are individually divided, and the excitation windings are wound around the pole teeth of each divided core. Connecting the wound split cores in a cylindrical shape, and then shrink-fitting the cylindrically connected split cores into a steel pipe having an inner diameter slightly smaller than the outer diameter of the connected split cores. And

According to the manufacturing method of the fifth aspect, the stator of the electric motor of the second aspect can be obtained. Moreover, since the exciting winding is wound around each pole tooth before connecting the split cores, the exciting winding can be wound in a free shape, and as a result, the exciting winding of the stator is not occupied. It is possible to improve the product ratio, and eventually to obtain a high-output electric motor.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan sectional view of the stepping motor 2 of the embodiment. As shown in FIG. 1A, the stepping motor 2 includes a cylindrical stator 4 and a stator 4.
And a rotor 6 which is rotatably arranged therein.

The stator 4 is formed in a cylindrical shape, and a plurality (eight in this embodiment) of pole teeth 8 (8a to 8h) are equally spaced along the circumferential direction of the inner peripheral surface thereof. And the pole teeth 8a to 8 of the stator core 10
Excitation coils 12 (12a to 1) wound around h, respectively.
2h), each pole tooth 8 around which the exciting coil 12 is wound forms a four-phase, eight-pole magnetic pole.

On the other hand, the rotor 6 is composed of a laminated iron core having six equidistant tooth portions 14 on its outer peripheral portion, and a shaft portion 16 at the center thereof is a bearing (not shown) on a side portion of the stator 4. It is rotatably supported via. That is, in the stepping motor 2 of the present embodiment, the pitch of the pole teeth 8 on the stator 4 side and the pitch of the tooth portions 14 on the rotor 6 side are deviated by 15 °, and a rotating magnetic field is generated in the pole teeth 8. Each excitation coil 1
It has a so-called variable reluctance type (VR type) configuration in which the rotor 6 is rotated by the electromagnetic attraction force from the pole teeth 8 when the energization state to 2 is switched.

Here, the stator core 10 has pole teeth 8a ...
Each of the core blocks 18 (18a to 18h) is formed of a laminated iron core that is evenly divided every 8 h, and a copper steel pipe 20 that surrounds the outer periphery of the core block 18. Of these, as shown in FIG. 1B, the core block 18 has a substantially T-shape in which the pole teeth 8 project from the central portion of the arc portion forming a part of the yoke toward the center of the arc. And the divided surfaces 19a, 1 located at both ends of the arc portion.
9b is a division surface 19b, 19a of the other core block 18.
One of the divided surfaces 19a is formed in a convex shape and the other divided surface 19b is formed in a concave shape so as to be fitted to each other.

On the other hand, in the exciting coil 12 wound around each pole tooth 8 of the stator core 10, the cross-sectional shape in the direction orthogonal to the axial direction of the stator core 10 is larger than the dimension of the tip end of the pole tooth H. The size of the stator core 10 on the yoke side is large and is formed in a substantially fan shape. The exciting coil 12 has a ring-shaped coil spool 22 having the above-mentioned cross-sectional shape and an enamel wire D.
The core block 18 is molded separately from the core block 18 by winding. Then, each exciting coil 12 is wound around each pole tooth 8 by fitting the hollow portion 22a of the coil spool 22 into the pole tooth 8, respectively.

The stator 4 as described above is manufactured as follows. First, the magnetic poles 8a to 8h of the core blocks 18a to 18h are connected to the exciting coils 12a to 1 having a substantially fan-shaped cross section.
Fit 2h respectively. Then, a magnetically permeable adhesive is applied to the divided surfaces 19a and 19b of the core block 18 in which the exciting coil 12 is inserted, and the divided surfaces 19a are formed in a convex shape.
To the concave surface 1 of the other core block 18.
By fitting and adhering to 9b and performing this sequentially,
The eight core blocks 18a to 18h are connected to form a cylindrical core block 18.

At the time of connecting the core blocks 18, the respective layers of the laminated iron core forming the core blocks 18 are connected so that they are all aligned with each other. Then, the core blocks 18 connected in a cylindrical shape are shrink-filled in a steel pipe 20 having an inner diameter slightly smaller than the outer diameter of the connected core blocks 18. That is, the core block 18 is fitted inside the steel pipe 20 in a state where the steel pipe 20 is heated and expanded so that the inner diameter thereof is larger than the outer diameter of the core block 18 connected in a cylindrical shape. After that, when the steel pipe 20 is cooled, the contracted steel pipe 20 presses the core block 18 connected in a cylindrical shape from the outer peripheral side, so that the connection shape of the core block 18 is maintained, whereby the stator 4
Is completed.

In the stepping motor 2 of the present embodiment constructed as described above, the exciting coil 12 fitted into each pole tooth 8 has a substantially fan-shaped cross section in the direction orthogonal to the axial direction of the stator core 10. Is formed in. Therefore, according to the stator 4 of the present embodiment, the space shown by the diagonal line K in FIG. 2B is occupied by the exciting coil 12, so that the space factor of the exciting coil 12 is increased. As a result, the output of the stepping motor 2 using the stator 4 can be improved.

Further, according to this embodiment, the stator core 10
Consists of a core block 18 divided for each pole tooth 8,
Since the exciting coil 12 can be wound around the pole teeth 8 in a state where the core block 18 is individually divided, the winding work can be easily performed. Moreover, the exciting coil 12
Has a very good workability because it is formed by winding the enameled wire D around the coil spool 22 in a predetermined shape in advance and only fitted into the pole teeth 8.

Further, in this embodiment, the dividing surfaces 19a and 19b of the core block 18 are made uneven so that the contact area between the core blocks 18 connected to each other is widened and the core blocks 18 are shrink-fitted. Core block 1
8 is strongly pressed in the direction in which the divided surfaces 19a and 19b are in close contact with each other.

Therefore, according to this embodiment, the dividing surface 19
Since the magnetic resistance at a and 19b is small, that is, the magnetic loss at the split surface is small, the stator 4 can efficiently generate magnetic flux, and the performance of the stepping motor 2 can be improved. Further, according to the present embodiment, since the magnetically permeable adhesive is applied to the dividing surfaces 19a and 19b of the core block 18, a gap is generated between the dividing surfaces 19a and 19b for some reason during manufacturing. Even so, since the magnetically permeable adhesive fills this gap, the magnetic loss at the divided surfaces 19a and 19b having the gap is not significantly increased, and the reliability of the stator 4 is improved. You can

Further, according to this embodiment, the dividing surfaces 19a,
By forming the concave and convex portions 19b and applying the magnetically permeable adhesive to the dividing surfaces 19a and 19b, the connected state of the core block 18 can be easily maintained even before the steel pipe 20 is shrink-fitted. Therefore, the assembly work of the stator 4 can be easily performed.

Furthermore, in this embodiment, the stator core 10
Is composed of the core block 18 divided for each pole tooth 8, the press device for manufacturing the core block 18 can be downsized as compared with the case of manufacturing an integrally molded stator core, and The base material pressed by the pressing device can also be downsized. Further, since the core block 18 has a relatively simple shape (substantially T-shaped), the base material can be effectively used.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be carried out in various modes without departing from the scope of the present invention. . For example, in the above-described embodiment, the exciting coil 12 is formed so that it can be fitted on the pole tooth 8, but the exciting coil 12 may be formed by directly winding the enamel wire D on the pole tooth 8.

In the above embodiment, the exciting coil 1 is formed by winding the enamel wire D on the coil spool 22.
2 is molded, but the exciting coil 12 is the coil spool 2
Instead of using 2, the enameled wire D alone may be formed into a ring shape.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a stepping motor according to an embodiment.

FIG. 2 is an explanatory diagram showing a configuration of a conventional motor stator.

FIG. 3 is an explanatory diagram showing a configuration of a conventional motor stator in which a space factor of an excitation winding is improved.

FIG. 4 is an explanatory diagram showing another configuration of a conventional motor stator in which the space factor of the excitation winding is improved.

5 is an explanatory diagram showing a problem of the stator shown in FIG.

[Explanation of symbols]

2 ... Stepping motor 4 ... Stator 6 ... Rotor 8 (8a-8h) ... Pole teeth 10 ... Stator core 12 (12a-12h) ... Excitation coil 14 ... Tooth portion
16 ... Shaft part 18 (18a-18h) ... Core block 19a, 1
9b ... Dividing surface 20 ... Steel pipe 22 ... Coil spool

Claims (5)

[Claims] 1. A stator core, which is formed in a cylindrical shape, and in which a plurality of pole teeth serving as magnetic poles are provided at equal intervals along a circumferential direction of an inner peripheral surface of the stator core so as to project toward a central axis direction. An exciting winding wound around each of the pole teeth, and a stator core of the electric motor, wherein the stator core is a split core formed by dividing the stator core for each pole tooth, A stator for an electric motor, comprising: an annular fixing member that presses the split cores connected in a cylindrical shape from the outer peripheral side to maintain the connected state of the split cores. 2. The stator of an electric motor according to claim 1, wherein the fixing member is made of a steel pipe that shrink-fits the split cores connected in a cylindrical shape. 3. A concave portion and a convex portion, which are fitted to each other when the split cores are connected in a cylindrical shape, are formed on each split surface of the split core. The stator of the electric motor according to claim 2. 4. The stator of an electric motor according to claim 1, wherein a magnetically permeable adhesive is applied to the split surface of the split core. 5. The manufacturing method for manufacturing the stator of the electric motor according to claim 2, wherein the divided cores are individually divided, and an excitation winding is provided on the pole teeth of each divided core. A steel pipe having windings and connecting the split cores around which the exciting windings are wound in a cylindrical shape, and then the split cores connected in a cylindrical shape having an inner diameter slightly smaller than the outer diameter of the connected split cores. A method for manufacturing a stator of an electric motor, comprising: