JP2008199711A - Stator - Google Patents

Abstract

In a stator in which a split stator core is fastened by an outer ring, leakage magnetic flux flowing from the split stator core to the outer ring is reduced.
A stator 20 for a motor in which a split stator core 21 having a back yoke portion 21a and a teeth portion 21b projecting inward from the back yoke portion 21a in an annular shape is arranged in an annular shape. An outer ring 30 for fastening that is externally fitted to the outer peripheral surface 21d of the divided stator core 21 is provided, and a non-leakage for reducing leakage magnetic flux is provided between the outer peripheral surface 21d of each divided stator core 21 and the inner peripheral surface 30b of the outer ring 30. A contact portion 30a is provided.
[Selection] Figure 1

Description

  The present invention relates to a motor stator, and more particularly, to reduce leakage magnetic flux flowing from a split stator core to an outer ring in a stator in which a split stator core arranged in an annular shape is fastened using an outer ring.

  Conventionally, as a stator core disposed on the outer periphery of a rotor of a motor, a split stator core obtained by dividing the stator core at a predetermined angle has been used for reasons such as ease of winding and space factor improvement. In the stator composed of the divided stator cores, the coils are wound around the teeth of each of the divided stator cores, arranged in an annular shape, fitted with a shrink-fit ring on the outer periphery thereof, and the shrink-fit ring is cooled. Thus, the inner diameter is reduced, and the outer peripheral surface of the divided stator core is pressed by a shrink-fitting ring to firmly connect the divided stator cores in an annular shape.

A stator core disclosed in Japanese Patent Application Laid-Open No. 2005-354838 (Patent Document 1) is provided as a stator in which a split stator core is integrally formed by this type of shrink fitting ring.
As shown in FIG. 16A, the stator core 1 is configured by connecting a plurality of divided stator cores 2 in the circumferential direction along the periphery of the rotor core 3. As shown in FIG. 16B, the divided stator core 2 includes a back yoke portion 2a, a tooth portion 2b protruding from the back yoke portion 2a toward the inner peripheral side, and a back yoke portion 2a sandwiching the teeth portion 2b. And a coil part 2c wound around the tooth part 2b. The back yoke portion 2a is arranged in a circumferential direction so as to be continuous in an annular shape, and a shrink-fitted ring that is expanded by heating is fitted on the outer peripheral surface of the back yoke portion 2a and then cooled to reduce the inner diameter, thereby dividing the stator core. The two are fixed.

JP 2005-354838 A

While the shrink-fitting ring is an iron ring, the split stator core is often formed of a powdered magnetic material obtained by press-molding magnetic powder made of iron. Since they are mixed and molded, the magnetic permeability of the shrink fitting ring may be higher than the magnetic permeability of the divided stator core.
For this reason, the magnetic flux flowing in the split stator core not only flows from the circumferential end of the back yoke portion of the split stator core to the adjacent split stator core, but also on the shrink-fitting ring that is in contact with the outer peripheral surface of the back yoke portion. Flowing. The magnetic flux flowing through the shrink fitting ring becomes a leakage magnetic flux, and eddy current is generated in the shrink fitting ring by electromagnetic induction, resulting in eddy current loss. The occurrence of the eddy current loss causes a reduction in motor efficiency, and there is room for improvement in these respects.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce leakage magnetic flux flowing from the split stator core to the outer ring in the stator in which the split stator core is fastened by the outer ring.

In order to solve the above problems, the present invention is a stator for a motor in which a split stator core having a back yoke portion and a teeth portion protruding from the back yoke portion into the stator in an annular shape is arranged,
An outer ring fitted on the outer peripheral surface of the split stator core arranged in an annular shape,
There is provided a stator comprising a non-contact portion between an outer peripheral surface of each of the divided stator cores and an inner peripheral surface of the outer ring.
Specifically, the divided stator core is made of a powder magnetic material, and the outer ring is a shrink fitting ring made of a magnetic material, and the magnetic permeability of the outer link is higher than the magnetic permeability of the divided stator core. is there.

In the present invention, as described above, the entire outer peripheral surface of the back yoke portion of the split stator core and the entire inner peripheral surface of the shrink-fitting ring are provided as noncontact portions. The non-contact portion has a lower magnetic permeability than the divided stator core. Because the shrink fit ring itself has higher permeability than the split stator core, magnetic flux also leaks from the contact surface between the outer peripheral surface of the back yoke and the inner peripheral surface of the shrink fit ring to the shrink fit ring. Although the magnetic flux becomes a magnetic flux, it is difficult for the magnetic flux to flow from the outer peripheral surface of the split stator core to the shrink fitting ring in the non-contact portion, and the leakage magnetic flux flowing in the shrink fitting ring is less than that in the case where the non-contact portion is not provided. Can be reduced.
On the other hand, since the outer peripheral surface of the split stator core and the inner peripheral surface of the shrink fitting ring are all in contact with each other except the non-contact portion, the shrink fitting ring can firmly fasten the split stator cores by shrink fitting. .

The non-contact portion is preferably a recess provided on the inner peripheral surface of the outer ring and / or the outer peripheral surface of the back yoke portion of the split stator core.
When the concave portion, which is a non-contact portion, is provided on either the inner peripheral surface of the outer ring or the outer peripheral surface of the split stator core, the machining operation is facilitated.
In addition, when recesses are provided in both the outer ring and the split stator core to form a single recess, the depth of the recesses provided in each of the outer ring and the split stator core can be reduced. The tightening stress can be concentrated in the recesses to prevent the split stator core and the outer ring from being deformed or damaged.

The depth in the radial direction of the recess is preferably increased to such an extent that the split stator core and the outer ring are not deformed or damaged by tightening the outer ring during shrink fitting. The greater the depth in the radial direction of the concave portion, that is, the longer the distance between the bottom surface of the concave portion and the divided stator core or the outer ring, the less the leakage magnetic flux from the divided stator core to the outer ring. The tightening stress of the outer ring concentrates on the recess, and the split stator core and the outer ring are likely to be deformed and damaged.
It is preferable that the area of the concave portion provided on the outer peripheral surface of the split stator core or the inner peripheral surface of the outer ring is widened within a range where shrink fitting with the outer ring is possible. If the area of the recess that is a non-contact part is large, the leakage magnetic flux flowing from the split stator core to the outer ring will be less, but if the area of the recess is too large, the contact surface between the outer peripheral surface of the split stator core and the inner peripheral surface of the outer ring This is because the outer ring cannot sufficiently tighten the split stator core during shrink fitting.

The non-contact portion may be a through hole provided in the outer ring instead of the recess.
When the non-contact portion is a concave portion, the leakage magnetic flux flowing to the shrink fitting ring is reduced in the concave portion, but the magnetic flux may flow to the outer ring through the bottom surface of the concave portion. On the other hand, when the non-contact part is a through hole, the magnetic flux can be prevented from flowing from the outer peripheral surface of the split stator core through the through hole to the shrink fitting ring.

It is preferable that the non-contact portion is positioned on the radially outer side of the tooth portion of each of the divided stator cores.
The magnetic flux flows in the radial direction from the tooth portion through the back yoke portion to the outer ring to become a leakage magnetic flux, and the back yoke portion located at the radially outer side of the tooth portion becomes a path through which the leakage magnetic flux flows to the outer ring. For this reason, by providing the contacted portion at the position of the back yoke portion, the path through which the leakage magnetic flux flows to the outer ring is shortened, and the magnetic flux flowing to the outer ring can be reduced.

The non-contact portion may be filled with a non-magnetic material.
When the non-contact portion is the concave portion or the through hole, the hollow portion of the concave portion or the through hole is filled with a nonmagnetic material made of an insulating resin material.
As described above, when the recess and the through-hole are filled with the nonmagnetic material, the split stator core and the outer ring come into contact with each other through the nonmagnetic material even in the noncontact portion. This can be done, and the divided stators can be fastened more firmly.

The non-contact portion is provided between the entire outer peripheral surface of the back yoke portion of each of the divided stator cores and the inner peripheral surface of the outer link,
A non-magnetic auxiliary ring may be interposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the back yoke portion, and the non-contact portion may be filled with the auxiliary ring.
The auxiliary ring made of the non-magnetic material may be externally fitted with the divided stator cores arranged in an annular shape, or may be fitted inside the outer ring for shrink fitting, together with the outer ring. You may interpose between an outer peripheral surface and an outer ring.

According to the above configuration, by providing the auxiliary ring made of a non-magnetic material on the inner peripheral surface of the outer ring, the outer ring, which is a magnetic material, does not directly contact the back yoke portion, and leakage from the back yoke portion to the outer ring Magnetic flux can be reduced.
On the other hand, since the stress of tightening the outer ring during shrink fitting is relieved by the auxiliary ring and is not directly applied to the back yoke portion, deformation and damage of the split stator core can be prevented.
In order to perform shrink fitting, it is preferable to use a heat resistant resin for the auxiliary ring.

Further, the non-contact portion is provided between the entire outer peripheral surface of the back yoke portion of each divided stator core and the inner peripheral surface of the outer link,
The entire outer peripheral surface of the back yoke portion of the divided stator core may be covered with a nonmagnetic insulating layer, and the noncontact portion may be filled with the insulating layer.

The insulating layer covering the entire outer peripheral surface of the back yoke portion is preferably formed on the divided stator core by outsert molding.
Even when the insulating layer is interposed, the back yoke portion and the outer ring are not in direct contact, and the leakage magnetic flux from the back yoke portion to the outer ring can be reduced. On the other hand, by providing the insulating layer, the stress of tightening the outer ring during shrink fitting is alleviated without being directly applied to the back yoke portion, so that deformation and damage of the split stator core can be prevented.

When the insulating layer is provided on the outer peripheral surface of the back yoke portion in the outsert molding, it is preferable to provide the insulating layer on the outer peripheral surface of the coil winding portion of the tooth portion at the same time.
The insulating layer may be provided as an insulating resin molded product instead of outsert molding, and may be fixed over the divided stator core.
By providing an insulating layer on the outer peripheral surface of the coil winding portion, the coil and the tooth portion can be insulated. In addition, the work process can be reduced by simultaneously forming the insulating layer on the outer peripheral surface of the back yoke portion and the coil winding portion of the tooth portion. Furthermore, the insulating layer provided on the outer peripheral surface of the back yoke portion and the coil winding portion of the tooth portion is formed as an integral insulating resin molded product, so that the insulating resin is respectively applied to the outer peripheral surface of the back yoke portion and the coil winding portion of the tooth portion. The number of parts can be reduced compared to the case where a molded product is provided.

  As described above, according to the stator of the present invention, since the non-contact portion is provided between the outer peripheral surface of the back yoke portion of the split stator core and the inner peripheral surface of the outer ring, no non-contact portion is provided. Compared to the case, the leakage magnetic flux flowing through the shrink fitting ring can be reduced.

Embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a first embodiment of the present invention. As shown in FIG. 1, the stator 20 according to the present invention includes a plurality of divided stator cores 21 arranged in an annular shape around a center point P1, and a grille fitted on the outer peripheral surface 21 d of the back yoke portion 21 a of the divided stator core 21. An outer ring 30 for fitting (hereinafter abbreviated as a shrink fitting ring 30) is provided. The stator 20 is arranged around the rotor 11 to constitute the motor 10.

  The split stator core 21 has a back yoke portion 21a joined to the adjacent split stator core 21, a tooth portion 21b protruding from the back yoke portion 21a inward in the radial direction of the stator 20, and a tooth portion 21b sandwiched between the tips of the tooth portions 21b. And a flange portion 21g provided opposite to the back yoke portion 21a, and a coil 24 is wound around the teeth portion 21b.

The divided stator core 21 is made of a powder magnetic material integrally formed by mixing a magnetic powder with a binder, pressurizing and compressing the binder, and then performing heat treatment. In this way, by molding with the powder compact, the split stator core 21 is axially (Y1), radial (Y2) and circumferential (Y3) as shown in FIGS. 2 (A), (B) and (C). ) Has a three-dimensional shape with irregularities.
That is, the back yoke portion 21a on the outer peripheral side in the radial direction Y2 of the tooth portion 21b having a substantially rectangular cross section protrudes in the axial direction Y1 from both ends in the axial direction Y1 of the teeth portion 21b and also protrudes in the circumferential direction Y3. . The flange 21g provided at the inner peripheral end of the tooth portion 21b protrudes in the circumferential direction Y3, but does not protrude in the axial direction Y1. Further, the peripheral surface of the flange portion 21g facing the rotor 11 has a concave arc shape, and when the divided stator core 21 is assembled in an annular shape, the peripheral surface of the flange portion 21g has the same circular shape with the center point P1 as the center. Placed in.
As shown in the side view of the split stator core 21 in FIG. 2B, the coil housing portion 21h is composed of a space surrounded by the inner peripheral surface of the back yoke portion 21a and the outer peripheral surface of the teeth portion 21b. As shown in the plan view of FIG. 4A, the space is surrounded by the inner peripheral surface of the back yoke portion 21a, the outer peripheral surface of the teeth portion 21b, and the inner peripheral surface of the flange portion 21g. As described above, the back yoke portion 21a protrudes from the teeth portion 21b in the axial direction (Y1) and the circumferential direction (Y3), so that the coil 24 accommodated in the coil accommodating portion 21 can be seen from the axial direction of the back yoke portion 21a. Can be rolled without protruding.

The shrink fitting ring 30 shown in FIG. 4 is made of iron, which is a magnetic material, and the magnetic permeability of the shrink fitting ring 30 is higher than that of the split stator core 21.
As shown in FIG. 3B, the inner peripheral surface 30b of the shrink-fitting ring 30 is at a position corresponding to the radially outer side of the teeth portion 21b of each of the divided stator cores 21 and one end in the axial direction. The other end is provided with a groove 30a which is a non-contact portion. In the present embodiment, the circumferential length L1 of the concave groove 30a is 2/3 of the circumferential length R1 of the tooth portion 21b on the inner circumferential surface of the back yoke portion 21a. Further, the depth L2 in the radial direction of the concave groove 30a is set to ¼ of the thickness R2 of the shrink fitting ring 30.

The stator 20 configured as described above is assembled in the following order.
First, as shown in FIG. 5A, the coil 24 is wound around the tooth portion 21b of each divided stator core 21 in advance.
Thereafter, the divided stator cores 21 are arranged in an annular shape.
In the case of the split stator core 21 not provided with the flange portion 21g, a coil 24 formed by winding a conducting wire in advance in a spiral shape may be inserted into the teeth portion 21b and then arranged in an annular shape. After being arranged in an annular shape, the coil 24 may be attached to the tooth portion 21b of each divided stator core.

Next, as shown in FIG. 5B, the shrink fitting ring 30 is thermally expanded so that the inner peripheral diameter of the shrink fitting ring 30 is larger than the outer peripheral diameter of the divided stator core 21.
As shown in FIG. 5C, the thermally expanded ring 30 for a burning spring is fitted on the outer periphery of the back yoke portion 21 a from above the split stator core 21.
In this state, the shrink fitting ring 30 is shrunk by the temperature drop, the outer peripheral surface 21d of the back yoke portion 21a is pressed by the shrink fitting ring 30, and the divided stator cores 21 are firmly connected in an annular shape. 1. The stator 20 shown in FIG.

In the stator 20 having the above-described configuration, the outer peripheral surface 21d of the back yoke portion 21a of the split stator core 21 and the inner peripheral surface 30b of the shrink-fitting ring 30 are not in contact with each other by the concave groove 30a and are not in contact with each other. As described above, since the contact surface between the outer peripheral surface 21d of the back yoke portion 21a and the inner peripheral surface 30b of the ring 30 for the firing spring, which is a path through which the leakage magnetic flux flows, is provided with the concave groove 30a that is a non-contact portion, In this non-contact portion, the path of the leakage magnetic flux flowing through the shrink fitting ring 30 can be blocked. Therefore, the leakage magnetic flux flowing through the shrink fitting ring 30 can be reduced as compared with the case where the non-contact portion is not provided.
Further, since the outer peripheral surface 21d of the back yoke portion 21a and the inner peripheral surface 30b of the shrink fitting ring 30 are in contact with each other at a portion other than the concave groove 30a, the outer peripheral surface 21d of the back yoke portion 21a of the split stator core 21 is shrink-fitted. The divided stator cores 21 can be firmly connected to each other by being pressed by the use ring 30.

FIG. 6 shows a modification of the first embodiment.
FIG. 6A is a first modified example, and the inner peripheral surface 30b of the shrink-fitting ring 30 does not project from positions corresponding to the radially outer side of the tooth portion 21b (both ends in the circumferential direction of the tooth portion 21b). Position) and a recess 30d is provided at the center in the axial direction Y1.
FIG. 6B shows a second modified example in which a concave groove 30e is provided continuously in the circumferential direction Y3 on the inner peripheral surface 30b of the shrink fitting ring 30 at the center in the axial direction Y1.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

7 and 8 show a second embodiment of the present invention.
A concave groove 21c, which is a non-contact portion, is provided on the outer peripheral surface 21d of the back yoke portion 21a of the split stator core 21 from one end to the other end in the axial direction at a position radially outside the tooth portion 21b.
The circumferential length L1 of the concave groove 21c is 2/3 of the circumferential length R1 of the teeth portion 21b on the inner circumferential surface of the back yoke portion 21a. Moreover, the depth L3 in the radial direction of the concave groove 21c is ¼ of the thickness R3 of the back yoke portion 21a.
Even if it is the said structure, the path | route of the leakage magnetic flux which flows into the ring 30 for shrink fitting can be interrupted | blocked, and the leakage magnetic flux which flows into the ring 30 for shrink fitting can be reduced compared with the case where the non-contact part is not provided. .
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 9 shows a modification of the second embodiment of the present invention.
FIG. 9A shows a first modification in which the concave groove 21e, which is a non-contact portion, is not provided from one end to the other end in the axial direction of the outer peripheral surface 21d of the back yoke portion 21a, but is provided at the central portion in the axial direction. ing.
FIG. 9B shows a second modified example, in which a concave groove 21f that is a non-contact portion is provided at the center portion in the axial direction of the outer peripheral surface 21d of the back yoke portion 21a from one end to the other end in the circumferential direction. Yes. The concave groove 21f is continuous with the concave groove 21f of the adjacent split stator, and becomes a concave groove 21f continuous with the outer peripheral surface 21d of the back yoke portion 21a of the split stator core assembled in an annular shape.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 10 shows a third embodiment of the present invention.
On the outer peripheral surface 21d of the back yoke portion 21a of the divided stator core 21, a groove 21c is provided from one end to the other end in the axial direction at a position radially outside the tooth portion 21b. Further, the inner peripheral surface 30b of the shrink fitting ring 30 is also provided with a groove 30a from one end to the other end in the axial direction at a position corresponding to the radially outer side of the tooth portion 21b. The concave groove 30 a of the shrink fitting ring 30 is formed as an integral groove 25.
According to the above configuration, since the concave grooves 30a and the concave grooves 21c are provided in both the split stator core 21 and the shrink-fitting ring 30, the depth of the concave grooves 30a and the concave grooves 21c can be reduced. The tightening stress of the shrink fitting ring 30 is concentrated on the concave groove 30a and the concave groove 21c, and deformation and damage of the split stator core 21 and the shrink fitting ring 30 can be prevented.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 11 shows a fourth embodiment of the present invention.
The shrink fitting ring 30 is provided with a substantially rectangular through hole 30c instead of the concave groove 30a at a position corresponding to the radially outer side of the tooth portion 21b of the split stator core 21.
According to the above configuration, since the path of the leakage magnetic flux flowing from the split stator core 21 to the shrink fitting ring 30 is blocked by the through hole 30c, it flows to the shrink fitting ring 30 as compared with the case where no contact portion is provided. Leakage magnetic flux can be reduced.
The through holes 30c are not limited to a rectangular shape, and a plurality of through holes 30c may be provided.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 12 shows a fifth embodiment of the present invention.
The concave groove 30a provided on the inner peripheral surface 30b of the shrink fitting ring 30 of the first embodiment is filled with a nonmagnetic resin 26, which is PPS resin, for example.
By filling the nonmagnetic resin 26, the shrink fitting ring 30 and the split stator core 21 are in contact with each other through the nonmagnetic resin 26 even in the recessed groove 30a. This is possible, and the divided stators can be firmly fastened.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. Further, the non-magnetic resin 26 may be filled in the groove 30a of the second embodiment, the third embodiment, and the fourth embodiment.

FIG. 13 shows a sixth embodiment of the present invention.
In the sixth embodiment, a non-magnetic auxiliary ring 30e is fitted to the inner peripheral surface of the shrink fitting ring 30 to form a double ring, and the auxiliary ring 30e is set annularly together with the shrink fitting ring 30. The split stator core 21 is fitted on the outer periphery. In the present embodiment, the back yoke portion 21a and the grilling spring ring 30 are not provided with recesses or through holes that are non-contact portions.
The auxiliary ring 30e is made of a non-magnetic resin such as engineering plastics such as PPS, epoxy-based, LCP, and polyimide.

As described above, when the auxiliary ring 30e made of a non-magnetic material is interposed between the inner peripheral surface of the shrink fitting ring 30 and the back yoke portion 21a of the divided stator core, the shrink fitting ring extends from the back yoke portion 21a. The leakage magnetic flux flowing to 30 can be reduced.
Further, since the auxiliary ring 30e is made of resin and is softer than the divided stator core 21 and the shrink fitting ring 30, the tightening stress of the shrink fitting ring 30 at the time of shrink fitting is relieved by the auxiliary ring 30e. Deformation and damage can be prevented.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

14 and 15 show a seventh embodiment of the present invention.
An insulating layer 33 made of a non-magnetic material is provided on the entire outer peripheral surface 21d of the back yoke portion 21a of the split stator core 21, and the insulating layer 33 is connected to the outer peripheral surface of the back yoke portion 21a and the inner peripheral surface of the shrink fitting ring 30. A non-contact portion is interposed between them.

As shown in FIG. 15, the insulating layer 33 is also provided on the inner peripheral surface 21a-5 of the back yoke portion 21a of the split stator core 21 and the upper and lower surfaces 21a-1 and 21a-2 of the axial direction Y1.
Further, upper and lower surfaces 21b-1, 21b-2 of the tooth portion 21b in the axial direction Y1, both side surfaces 21b-3, 21b-4 in the circumferential direction Y3, and both side surfaces 21g-1, 21g- in the circumferential direction Y3 of the flange portion 21g. 2 and the tooth portion side surface 21g-3 in the radial direction Y2 of the flange portion 21g are also provided with the insulating layer 33.
The insulating layer 33 is not provided on the side surfaces 21a-3 and 21a-4 in the circumferential direction Y2 of the back yoke portion 21a and the side surface 21g-4 on the radial center point P side of the flange portion 21g.
The insulating layer 33 is outsert molded.

The insulating layer 33 made of the non-magnetic material is formed of a resin such as engineering plastics such as PPS, epoxy-based, LCP, and polyimide, for example.
The thickness of the insulating layer 21h is set to 0.3 mm to 0.8 mm on the outer peripheral surface 21d of the back yoke portion 21a. This is because if it is larger than 0.8 mm, tightening by the shrink fitting ring 30 becomes weak, and if it is smaller than 0.3 mm, the leakage magnetic flux tends to flow to the outer ring 30. In this embodiment, it is 0.5 mm.
The insulating layer 33 is resistant to compressive stress of 100 MPa or more due to the physical properties and thickness of the resin material, and does not change even at a temperature of about 150 degrees, and has heat dissipation.

  The thickness of the insulating layer 33 on the side surfaces 21b-1 to 21b-4 of the tooth portion 21b and the side surfaces 21g-1 to 21g-3 of the flange portion 21g is preferably 0.3 mm to 0.5 mm, and in this embodiment 0.4 mm. It is said. This is because if it is larger than 0.5 mm, the space for winding the coil 24 is reduced, and if it is smaller than 0.3 mm, the coil 24 and the tooth portion 21b are hardly insulated.

According to the above configuration, since the nonmagnetic insulating layer 33 is interposed between the outer peripheral surface of the back yoke portion 21 a and the shrink fitting ring 30, the magnetic flux hardly flows and flows into the shrink fitting ring 30. Leakage magnetic flux can be reduced. On the other hand, by providing the insulating layer 33, the tightening stress of the shrink-fitting ring 30 at the time of shrink-fitting is relieved without being directly applied to the back yoke portion 21a, so that deformation and damage of the split stator core 21 are prevented. be able to.
Further, if the insulating layer 33 is provided on the tooth portion 21b simultaneously with the outer peripheral surface 21d of the back yoke portion 21a, it is not necessary to separately provide an insulating layer between the tooth portion 21b and the coil 24. This can reduce the number of parts as well as the number of parts.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In addition, this invention is not limited to the said embodiment, The various form within the claim of this invention is included.

It is a perspective view which shows 1st Embodiment of the stator which is this invention. A split stator core is shown, (A) is a perspective view, (B) is a side view, and (C) is a front view. (A) is a front view of a stator, and (B) is an enlarged view of a main part. It is a perspective view of a ring for shrink fitting. (A)-(C) are explanatory drawings of the assembly process of a stator. (A) of 1st Embodiment is a figure which shows a 1st modification, (B) is a 2nd modification. A 2nd embodiment is shown and (A) is a front view of a stator and (B) is an important section enlarged view. It is a perspective view of a split stator core. It is a figure which shows the modification of 2nd Embodiment, (A) is a 1st modification, (B) is a figure which shows a 2nd modification. It is a figure which shows 3rd Embodiment, (A) is a front view of a stator, (B) is a principal part enlarged view. It is a figure which shows 4th Embodiment, (A) is a perspective view of a stator, (B) is a principal part enlarged view. It is a principal part enlarged view which shows 5th Embodiment. It is a figure which shows 6th Embodiment, (A) is a front view of a stator, (B) is a perspective view of an outer ring. It is a front view of the stator which shows 7th Embodiment. It is (A) perspective view, (B) AA sectional drawing, (C) BB sectional drawing of a split stator core. It is a figure which shows a prior art example.

Explanation of symbols

20 Stator 21 Divided stator core 21a Back yoke portion 21b Teeth portion 21c, 30a Recessed groove 21d Outer peripheral surface of back yoke portion 24 Coil 25 Integrated groove 26 Nonmagnetic resin 30 Shrink fit ring 30b Inner peripheral surface of shrink fit ring 30c Through-hole 30e Auxiliary ring 33 Insulating layer L1 Circumferential length L2 Concave groove radial depth R1 Teeth circumferential length R2 Shrink fit ring thickness P1 Center point

Claims (8)

A stator for a motor in which a split stator core having a back yoke portion and a teeth portion projecting inward from the back yoke portion is arranged in an annular shape,
An outer ring fitted on the outer peripheral surface of the split stator core arranged in an annular shape,
A stator comprising a non-contact portion between an outer peripheral surface of each of the divided stator cores and an inner peripheral surface of the outer ring.   The split stator core is made of a powder magnetic material, and the outer ring is a shrink-fit ring made of a magnetic material, and the magnetic permeability of the outer link is higher than the magnetic permeability of the split stator core. The stator described.   3. The stator according to claim 1, wherein the non-contact portion includes a concave portion provided on an inner peripheral surface of the outer ring and / or an outer peripheral surface of the back yoke portion of the split stator core.   The stator according to claim 1, wherein the non-contact portion includes a through hole provided in the outer ring.   The stator according to any one of claims 1 to 4, wherein the non-contact portion is positioned on a radially outer side of the tooth portion of each of the divided stator cores.   The stator according to claim 1, wherein the non-contact portion is filled with a non-magnetic material. The non-contact portion is provided between the entire outer peripheral surface of the back yoke portion of each of the divided stator cores and the inner peripheral surface of the outer link,
The non-magnetic auxiliary ring is interposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the back yoke portion, and the auxiliary ring is filled in the non-contact portion. Stator. The non-contact portion is provided between the entire outer peripheral surface of the back yoke portion of each of the divided stator cores and the inner peripheral surface of the outer link,
The stator according to claim 1 or 6, wherein the entire outer peripheral surface of the back yoke portion of the divided stator core is covered with a non-magnetic insulating layer, and the non-contact portion is filled with the insulating layer.

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