JPH08266013A - Electric motor - Google Patents

Abstract

(57) [Summary] [Purpose] In motors used for general and industrial purposes,
Solves problems such as insufficient strength of the can and deterioration of magnetic efficiency due to large magnetic space (magnetic air gap) between the stator and rotor, and direct liquid cooling of the stator windings for compact high output The purpose is to achieve [Structure] A can 3 having a substantially male screw shape having a plurality of grooves on the outer peripheral portion and at least the axial dimension of the stator made of a magnetic material is engaged with a stator 2 having an inner diameter portion having a substantially female screw shape. Then, the stator winding is directly liquid cooled to achieve a small size and high output.
A small and high-output electric motor can be obtained by improving the can strength due to the reinforcing rib effect of the screw portion of the can 3 and reducing the eddy current loss due to the laminated structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to electric motors used for industrial purposes.

[0002]

2. Description of the Related Art In recent years, machines equipped with electric motors tend to be small in size and high in output, and from the viewpoint of energy saving, it is desired that the electric motors to be installed are also small in size and high in output. By efficiently dissipating and cooling the heat generated by the electric motor, it may be possible to achieve a small size and high output. Therefore, it is highly effective to directly cool the stator winding, which is the main heat source in the electric motor.

An electric motor in which a conventional stator winding is directly cooled by, for example, cooling water will be described below.

FIG. 13A is a partial sectional view of a conventional electric motor. In FIG. 13A, 21 is a rotor, 22 is a stator, 23 is a can, 24 is a frame, 25 is a winding,
26 indicates a bracket.

FIG. 13 (b) is a half sectional view of the same motor seen from the direction of arrow KL in FIG. 13 (a). The rotor 21 is rotatably supported by a bracket 26 via a bearing (not shown). The inner surface of the stator 22 has a cylindrical can 2
3 is inserted coaxially. The stator 22 is kept airtight by the frame 24, the bracket 26, and the can 23, and the stator and the windings are efficiently cooled by the cooling liquid.

The can 23 is generally made of a non-magnetic material, for example, austenitic stainless steel, so as to prevent adverse effects on the magnetic circuit such as leakage flux between adjacent teeth of the stator.

[0007]

However, in the above conventional structure, the magnetic space (magnetic air gap) between the stator and the rotor is actually fixed because the can is made of a non-magnetic material. In addition to the space (mechanical air gap) between the child and the rotor, the wall thickness of the can becomes wider, and the magnetic efficiency deteriorates as compared with an electric motor that does not require a can. For this reason, it is desirable that the thickness of the can is as thin as possible, but considering the force that acts on the can such as the liquid pressure of the stator cooling liquid, it is necessary to increase the strength of the can. There was a limit. Therefore, the electric motor using the conventional can has a problem that the characteristics are deteriorated due to the deterioration of the magnetic efficiency as compared with the electric motor which does not require the can, and it is difficult to achieve a small size and high output.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a small-sized and high-output electric motor.

[0009]

To achieve this object, an electric motor according to the present invention has a substantially male screw shape in which a plurality of grooves are arranged in the outer peripheral portion, and at least the axial dimension of the stator is made of a magnetic material. Is provided in a stator having an internal thread portion in the shape of a female thread, or a can having a plurality of L-shaped projection rows or L-shaped projections on the outer peripheral portion and at least the axial dimension of the stator is made of a magnetic material. The L-shaped projection row or the L-shaped projection portion is engaged with a hole or a groove of a stator tooth portion.

[0010]

With this structure, since the can is made of a magnetic material, the magnetic air gap is not increased over the mechanical air gap, and the characteristics of the electric motor due to the use of the can are not deteriorated. Further, since the can is provided with a screw shape, this screw portion gives the effect of a reinforcing rib to the cylindrical can, and the strength of the can is increased. The stator of this electric motor is intended to reduce eddy current loss and the like, that is, iron loss, by stacking electromagnetic steel sheets having a plate thickness of about 0.3 mm to 0.5 mm. The threaded portion of the can engages with the threaded portion of the stator made of laminated steel plates,
The laminated structure reduces eddy current loss and the like, that is, iron loss can be reduced and can strength can be improved without deteriorating the characteristics.

[0011]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a partial sectional view of an electric motor according to the first embodiment of the present invention. In FIG. 1A, 1
Is a rotor provided with a rotary shaft, 2 is a stator, 3 is a can arranged inside the stator 2, 4 is a stator winding, 5 is a frame, and 6 is a bracket. Rotor 1 has both brackets 6
Is rotatably supported coaxially with the stator 2 via a bearing (not shown). The stator 2 includes a stator winding 4.
A can 3 is arranged in the stator inner diameter portion of the space (air gap) between the stator 2 and the rotor 1. Note that FIG. 1 (b)
Shows a half cross-sectional view taken along the arrow A-B along the external thread portion of the can of FIG. FIG. 2 shows a side view of the can 3 and a view from the direction of the rotation axis. 3a is a male screw portion and 3b is a groove portion.

Regarding the electric motor configured as described above,
The operation will be described. This electric motor, like a general electric motor, obtains a rotational torque in the rotor 1 by an electromagnetic force caused by repeating an electric current flowing through a certain phase of the stator winding 4 to excite it. Can 3
The stator 2 and the stator winding 4 which are kept airtight are directly liquid-cooled by a cooling liquid.

In the present invention, since the can 3 is made of a magnetic material,
In a motor using a can made of a general non-magnetic material, the characteristics are not deteriorated due to an increase in magnetic air gap. However, since the can is made of a magnetic material and the pole teeth (hereinafter referred to as teeth) of the stator are connected to each other, the leakage flux between the stator teeth is increased, while the groove 3b of the can is fixed to the stator 2. By arranging between the teeth, the magnetic material in that part is thinned, and magnetic flux saturation occurs in that part,
Leakage magnetic flux between adjacent teeth is reduced. Therefore, although the present invention uses the can made of a magnetic material, the leakage flux can be reduced and the deterioration of the characteristics of the motor is reduced.

Further, since the can has a screw shape, the screw portion 3a serves as a reinforcing rib for the cylindrical can,
In consideration of the cooling liquid pressure and the like, a thin can having a required strength can be obtained. Further, the threaded portion of the can engages with the threaded portion of the stator made of laminated steel plates to form a laminated structure, and eddy current loss, that is, iron loss does not increase in that portion, and deterioration of characteristics can be prevented.

As described above, according to this embodiment, the can has a substantially male screw shape in which a plurality of grooves are arranged on the outer peripheral portion, and at least the axial dimension of the stator is made of a magnetic material, and the inner diameter portion. Due to the configuration of the stator having a substantially female thread shape, the characteristics of the electric motor due to the use of the can are not significantly deteriorated without increasing the magnetic air gap over the mechanical air gap. Further, since the can has a screw shape, the effect of the reinforcing rib is obtained and the can can be made thin. Furthermore, the screw part of the can engages with the screw part of the stator made of laminated steel plates to form a laminated structure, and eddy current loss in that part, that is, iron loss, does not increase, and deterioration of characteristics can be prevented. It is possible to provide an excellent electric motor with high output.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a partial sectional view of the electric motor according to the second embodiment. In FIG. 3, 1 is a rotor, 3 is a can, 4 is a stator winding, 5 is a frame, and 6 is a bracket. The above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that the configuration of the screw portion of the inner diameter portion of the stator 7 is changed. The details are shown in FIGS.
Will be explained.

FIG. 4 is a half sectional view of the stator 7 of this embodiment,
4 is a half cross-sectional view taken along arrow C-D in FIG. 3. Figure 5
Shows the teeth of the stator iron plate 8 forming the stator 7. FIG. 6 shows a development view of the screw portion as seen from the inner diameter side of the stator 7 and a cross-sectional view taken along the arrow EF. 6A, M and N indicate the M and N parts of FIG.

The structure of the threaded portion of the stator 7 is indicated by diagonal lines in the drawing shown in FIG. Stator teeth 8a, 8b with different inner diameters by twisting the tip of the pole teeth by a certain angle θ
The stator iron plates 8 having the above are laminated to form the screw portion by a simple method. At this time, as shown in FIG. 6, the inner diameter of the teeth portion of the stator iron plate is selected and the bending angle is set to an appropriate value so that the shape formed by each tooth becomes a continuous screw shape.

Further, in the present embodiment, the number of teeth is 8, but it is preferable that the width of the teeth (female screw forming portion) is relatively smaller than the inner diameter of the stator (the stator having many slots). It is added that the structure of the section can be done easily. Further, it goes without saying that the present embodiment can be implemented even when the shape of the slots is different or the stator in which the teeth are not evenly spaced.

As described above, according to this embodiment, since the screw shape of the inner diameter portion of the stator can be constructed by a simple method, it is easy to obtain the same effect as that of the first embodiment, and the small size and high output can be obtained. An excellent electric motor can be provided.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 shows a partial sectional view of an electric motor according to the third embodiment. In FIG. 7, 1 is a rotor, 4 is a stator winding, 5 is a frame, and 6 is a bracket. The above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that the configurations of the stator 9 and the can 10 are changed, which will be described below with reference to FIG. FIG. 8 shows a partial cross-sectional view taken along arrow GH in FIG. Reference numeral 9a is a plurality of slots in the teeth portion of the stator 9, and 10a is a can 10.
Showing a plurality of L-shaped protrusions on the outer peripheral portion of the can, and a plurality of L-shaped protrusions 10a of the can in the slots 9a of the stator teeth.
Is engaged.

In the present invention, since the can 10 is made of a magnetic material, deterioration of the characteristics does not occur due to an increase in the magnetic air gap in an electric motor using a can made of a general non-magnetic material. Since the can is made of a magnetic material and the teeth of the stator are connected to each other, the leakage magnetic flux between the stator teeth increases. However, since the L-shaped protrusion 10a reinforces the cylindrical can, the wall thickness of the can can be reduced. Then, by thinning the can, the leakage flux between the adjacent teeth of the stator is saturated and the leakage flux is reduced.

As described above, in this embodiment, the leakage magnetic flux is reduced to reduce the deterioration of the characteristics of the electric motor.

The plurality of L-shaped projections 10a of the can, which engage with the slots 9a of the stator teeth, are always in the same circumferential direction. That is, at the time of assembly, the can is inserted into the inner diameter portion of the stator so that the L-shaped projection of the can is located between the stator teeth, and the can is rotated and engaged.

As described above, since the plurality of L-shaped projections of the can made of the magnetic material are engaged with the plurality of slots of the teeth of the stator, the magnetic air gap is not increased and the can is prevented. The characteristics of the electric motor will not be significantly deteriorated by using it. Further, the plurality of L-shaped projections makes it possible to obtain the required strength with a thin can in consideration of the cooling liquid pressure and the like.

Further, as shown in FIG. 7, the L-shaped protrusion 10a of the can engages with the slot of the stator formed by laminating electromagnetic steel sheets to form a laminated structure, and eddy current loss in that portion, that is, It is possible to prevent an increase in iron loss, prevent deterioration of characteristics, and provide an excellent electric motor that is small in size and high in output.

(Embodiment 4) A fourth embodiment of the present invention will be described below with reference to the drawings.

FIG. 9 is a partial sectional view of an electric motor according to the fourth embodiment of the present invention. In FIG. 9, 1 is a rotor, 4
Is a stator winding, 5 is a frame, and 6 is a bracket. The above is the same as the configuration of FIG. FIG.
The configuration is different from that of FIG. 11 in that the stator 11 and the can 12 are changed, which will be described below with reference to FIG. FIG. 10 is a partial sectional view taken along line GH in FIG.
11a is a plurality of grooves on the teeth of the stator 11,
Shows a plurality of L-shaped projection rows on the outer peripheral portion of the can 12, and has a configuration in which a plurality of L-shaped projection rows 12a of the can are engaged with the grooves 11a of the teeth portion of the stator 11.

In the present invention, since the can 12 is made of a magnetic material, deterioration of characteristics due to an increase in magnetic air gap in an electric motor using a can made of a general non-magnetic material does not occur. By forming the can with a magnetic material and connecting the pole teeth (teeth) of the stator, the leakage flux between the stator teeth increases. However, since the L-shaped projection row 12a reinforces the cylindrical can, the wall thickness of the can can be reduced. By thinning the can, the leakage flux between adjacent teeth of the stator is saturated and the leakage flux is reduced.

Therefore, although a can made of a magnetic material is used, consideration is given to reduce the deterioration of the characteristics of the electric motor by reducing the leakage magnetic flux.

One of the features of this embodiment is that the can 12 has a shape that can be inserted in the axial direction. That is, by assembling the L-shaped protrusion 12a of the can in the axial direction so as to engage with the groove 11a of the tooth portion of the stator 11, there is an effect that the assembly is easy.

Further, by considering the required strength, the number of the projection rows is reduced, or the projection rows are made to have the same projections as in the third embodiment, so that the eddy current loss, that is, the iron loss at that portion is reduced. It is possible to provide an excellent electric motor that is small in size and high in output, because the characteristics can be prevented from being deteriorated without increasing.

(Embodiment 5) A fifth embodiment of the present invention will be described below with reference to FIG.

In FIG. 11, 1 is a rotor, 2 is a stator, 4 is a stator winding, and 5 is a frame. The above is the same as the configuration of FIG. 1 is different from the configuration of FIG. 1 in that the can 13 is made slightly shorter than the axial dimension of the stator 2 and the fitting portion of the non-magnetic bracket 14 with the can 13 is moved toward the stator side. It is the point that the configuration is close.

In this embodiment, the axial dimension of the can 13 is almost the same as that of the stator 2, that is, the magnetic loss is increased only by arranging the magnetic material only in the portion facing the rotor. Leakage magnetic flux leaking through the magnetic material can be reduced. Further, by shortening the axial dimension of the can, the distance between both ends supporting the can is shortened, and the strength is improved.

FIG. 12 is a side view of the can. The can 15 shown in FIG. 12 is composed of a magnetic material 15a and a non-magnetic material 15b. By configuring the can 15 in place of the can 3 in FIG. 1, the same effect as that of this embodiment can be obtained. Although this embodiment is a modification of the can of the first embodiment, it goes without saying that the same effects can be obtained in the second, third, and fourth embodiments by using the same structure as this embodiment.

[0040]

As described above, the present invention has a can made of a magnetic material for at least the axial dimension of the stator having a substantially male thread shape in which a plurality of grooves are arranged on the outer peripheral portion, and a substantially female thread at the inner diameter portion. Engage with a shaped stator, or multiple L
An array of L-shaped projections, or a can provided with at least the axial dimension of the stator provided with L-shaped projections and made of a magnetic material, and a configuration in which the L-shaped projections are engaged with slots in the stator teeth. This prevents the deterioration of the characteristics of the electric motor due to the increase of the magnetic air gap due to the use of the can, and because the can has a screw shape, the effect of the reinforcing rib is given to the can having a cylindrical screw part. The strength of the can is increased and the can can be made thinner. Furthermore, the screw part of the can engages with the screw part of the stator formed by stacking electromagnetic steel plates to form a laminated structure, which reduces eddy current loss, that is, iron loss. It is possible to reduce the noise, prevent the deterioration of the characteristics, and eliminate the unevenness of the inner diameter of the stator, thereby realizing a small size and high output electric motor with reduced wind noise, magnetic noise and torque ripple.

[Brief description of drawings]

FIG. 1A is a partial cross-sectional view of an electric motor according to a first embodiment of the present invention. FIG. 1B is a half cross-sectional view taken along the line AB of FIG. 1A.

FIG. 2 is a view seen from a side surface of the can and a rotation axis direction.

FIG. 3 is a partial sectional view of an electric motor according to a second embodiment of the present invention.

FIG. 4 is a half sectional view taken along the line CD of FIG.

FIG. 5 is a view showing teeth of a stator iron plate of an electric motor according to a second embodiment of the present invention.

FIG. 6 (a) is a development view of a screw portion seen from the inner diameter side of the stator in the same embodiment (b) A cross-sectional view taken along the line EF in FIG. 6 (a)

FIG. 7 is a partial sectional view of an electric motor according to a third embodiment of the present invention.

FIG. 8 is a partial sectional view taken along the line GH in FIG.

FIG. 9 is a partial sectional view of an electric motor according to a fourth embodiment of the present invention.

FIG. 10 is a partial cross-sectional view taken along the arrow IJ of FIG.

FIG. 11 is a partial sectional view of an electric motor according to a fifth embodiment of the present invention.

FIG. 12 is a side view of the can according to the embodiment.

13A is a partial cross-sectional view of a conventional electric motor, and FIG. 13B is a half cross-sectional view of KL in FIG. 13A.

[Explanation of symbols]

 1,21 Rotor 2,7,9,11,22 Stator 3,10,12,13,15,23 Can 3a Male screw part 3b Groove part 4,25 Stator winding 5,24 Frame 6,14,26 Brackets 8a, 8b Stator iron plates 9a, 11a Plural slot holes 10a, 12a on the teeth of the stator Plural L-shaped projections on the outer periphery of the can 15a Magnetic can 15b Non-magnetic can

Claims (5)

[Claims] 1. A can made of a magnetic material, which has a substantially male thread shape by arranging a plurality of grooves in the thread portion of an external thread on the outer periphery of a thin-walled cylinder, has an inner diameter part having a substantially female thread shape. An electric motor characterized by being engaged with a stator. 2. A stator iron plate having different inner diameters, wherein pole teeth portions (teeth) in the inner diameter direction of the stator iron plate are twist-laminated at a constant angle, and the stator has a stator having a substantially female threaded inner diameter portion. The electric motor described. 3. A can having a plurality of L-shaped projections in the same circumferential direction on the outer periphery and at least the axial dimension of the stator being made of a magnetic material, and the L-shaped projections being a stator pole tooth portion. An electric motor characterized by being engaged with a hole or groove of (teeth). 4. A can having at least an axial dimension of a stator, which is provided with a plurality of L-shaped projection rows on the outer peripheral portion, made of a magnetic material; An electric motor characterized by being engaged with a hole. 5. The method according to claim 1, wherein at least one axial dimension of the stator is made of a magnetic material, and at least one end thereof has a can made of a non-magnetic material. Electric motor.