WO2025220110A1 - Stator and electric motor - Google Patents

Abstract

A stator (1) comprises: an iron core (10) provided with a back yoke (11) and a plurality of teeth (12) that protrude from the back yoke toward a movable element (5) side and that are arranged at intervals along a drive direction of the movable element; a plurality of coils (20) respectively wound around the teeth; and a sealing member (30) providing a liquid-tight seal to each slot formed between mutually adjacent teeth. The sealing member has a first sealing part (31) disposed in a gap between the tips of the mutually adjacent teeth, and a second sealing part (32) disposed, on at least one side of the teeth in the thickness direction, in a position covering the end surfaces at least on the tip side of all the teeth in the thickness direction and the end surfaces of all the first sealing parts in the thickness direction. The second sealing part can be brought into close contact with a housing (6) housing the iron core and the coils. The first sealing part and the second sealing part are integrally formed.

Description

Stator and motor

This disclosure relates to a stator and an electric motor.

A rotating electric machine is known in which a refrigerant is circulated inside each slot to cool coils arranged in multiple slots arranged along the circumferential direction of a cylindrically formed stator core (see, for example, Patent Document 1).
Such a rotating electric machine forms a refrigerant flow path by forming a resin layer at the radially inner opening of each slot and by placing a sealing member between both axial end faces of the stator core and a pair of cases that cover them.

Japanese Patent Application Laid-Open No. 2003-289652

Each of the above seal members is pressed axially outward against the stator core by the corresponding case, but if the axial dimensions of the stator are uneven, a gap may form between the seal member and the stator core. If the refrigerant leaks out of the gap, it will contaminate other components that make up the rotating electrical machine.
Therefore, it is desirable to be able to more reliably seal the flow path of the coolant for cooling the coils attached to the stator core.

One aspect of the present disclosure is a stator comprising: a back yoke; an iron core including a plurality of teeth protruding from the back yoke toward a mover and spaced apart in the drive direction of the mover; a plurality of coils wound around each of the teeth; and a sealing member that liquid-tightly seals each slot formed between adjacent teeth, the sealing member comprising: a first sealing portion disposed in the gap between the tips of the adjacent teeth; and a second sealing portion disposed on at least one side of the teeth in the thickness direction, in a position that covers at least the tip-side end faces of all of the teeth in the thickness direction and the thickness direction end faces of all of the first sealing portions, and that can be tightly fitted to a housing that accommodates the iron core and the coils; the first sealing portion and the second sealing portion being integrally formed.

FIG. 1 is a perspective view illustrating a portion of an electric motor according to an embodiment of the present disclosure. 2 is a schematic view showing a cross section of the electric motor shown in FIG. 1 taken along line AA. FIG. 2 is a perspective view illustrating a portion of a stator core according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view of a portion of a stator according to one embodiment of the present disclosure. 5 is a longitudinal cross-sectional view of a portion of a sealing member included in the stator shown in FIG. 4. FIG. FIG. 5 is a perspective view showing a cross section of a first modified example of a sealing member provided in the stator shown in FIG. 4 . FIG. 5 is a cross-sectional view showing a second modified example of a sealing member provided in the stator shown in FIG. 4 . FIG. 2 is a partial cross-sectional view showing a modification of the electric motor shown in FIG. 1 .

A stator 1 and an electric motor 100 according to an embodiment of the present disclosure will be described below with reference to the drawings.
The electric motor 100 according to this embodiment is, for example, a rotary motor. As shown in Fig. 1, the electric motor 100 includes a cylindrical stator 1 having a central axis along axis X, and a columnar rotor (movable element) 5 arranged coaxially with a predetermined gap inward in the radial direction of the stator 1. The electric motor 100 also includes a housing 6 that accommodates the stator 1, as shown in Fig. 2.

2, the rotor 5 includes a cylindrical main body 51 having a central axis on the axis X, and a shaft 52 that protrudes outward along the axis X from one end face of the main body 51 in the axis X direction. The main body 51 and the shaft 52 are arranged coaxially and are integrally configured. The rotor 5 is supported rotatably about the axis X by a bearing (not shown) attached to a housing 6, which will be described later.
The main body 51 is positioned so as to overlap the stator 1 and the housing 6 in the direction of the axis X, and the shaft 52 is positioned so that its tip protrudes outward from the housing 6 in the direction of the axis X.

As shown in FIGS. 1 and 2 , the stator 1 includes a substantially cylindrical iron core 10 that surrounds the outer circumferential surface of the main body 51 of the rotor 5 from the radially outer side, a coil 20 , and a sealing member 30 .
Core 10 is an integrated laminate formed by stacking a plurality of members, each member being punched into the same shape from thin plates made of a magnetic material such as electromagnetic steel, in the plate thickness direction. That is, in this case, the stacking direction of the plurality of thin plate members is defined as the thickness direction of core 10. As shown in Figures 1 and 3, core 10 includes a cylindrical back yoke 11 whose central axis is axis X, and a plurality of teeth 12 that protrude radially inward from the inner peripheral surface of back yoke 11 and are arranged at equal intervals in the circumferential direction.

A slot S is formed between each pair of teeth 12 that are adjacent to each other in the circumferential direction. As shown in Figure 3, each slot S has a rectangular opening 14 that opens radially inward and extends over its entire length in the direction of the axis X.

The coils 20 are, for example, a group of multiple coils corresponding to three phases, U, V, and W, and are wound around each tooth 12 using distributed winding or concentrated winding. In other words, the coils 20 are arranged so that each phase (U, V, W) is repeated in a predetermined order around the circumference. As a result, when a three-phase AC drive current is input to the coils 20, a magnetic flux is generated that rotates the rotor 5 around the axis X.

As shown in FIG. 2 , the sealing member 30 includes a first sealing portion 31 and a second sealing portion 32 .
4, the first sealing portion 31 is formed by filling a resin material such as epoxy resin or unsaturated polyester into a wall shape having a predetermined thickness at a position that closes the opening 14 of each slot S. When forming the first sealing portion 31, for example, a jig (not shown) that defines a cavity to be filled with molten resin material may be placed using a known method, and the jig may be removed after the filled resin material has hardened.

The first sealing portion 31 has an inner circumferential surface 31i that is continuous circumferentially with the inner circumferential surfaces of the tips of the teeth 12 located on both sides circumferentially about the axis X. The first sealing portion 31 also has an outer circumferential surface 31o that is positioned offset a predetermined distance radially outward from the inner circumferential surface 31i. In other words, the first sealing portion 31 liquid-tightly seals the opening 14 of each slot S, creating an enclosed space (flow path) within each slot S that extends in the direction of the axis X.

2, the second sealing portions 32 are configured by annular members with a substantially rectangular cross section made of a resin material different from that of the first sealing portions 31, and one is disposed on each side of the core 10 in the direction of the axis X. Each second sealing portion 32 is disposed coaxially with the axis X and has an annular bottom surface (end surface) 32b that continuously covers the end surfaces of the tips of all of the teeth 12 on the corresponding side in the direction of the axis X.
Furthermore, the second sealing portion 32 has an inner surface 32i having an inner diameter dimension that is the same as or slightly larger than the inner surface 31i of the first sealing portion 31, and an outer surface 32o having an outer diameter dimension that is the same as or slightly smaller than the outer surface 31o of the first sealing portion 31.

Furthermore, the second sealing portion 32 is integrated with the first sealing portion 31 by insert molding when the first sealing portion 31 is molded. That is, as shown in FIG.
A part of the bottom surface 32b of each second sealing portion 32 is in close contact with the end surface of the tip of the tooth 12 in the direction of the axis X, and the remaining part is connected to the end surface of the first sealing portion 31 in the direction of the axis X.

As shown in Figure 2, the housing 6 is composed of a cylindrical body 61 that surrounds the outer radial side of the core 10, and a pair of lids 62 that are tightly attached to both end faces of the body 61 in the direction of the axis X.

The dimension of the body 61 in the axial X direction is set to be larger than the dimension of the iron core 10 in the axial X direction. The body 61 also has an inner circumferential surface 61i with an inner diameter dimension slightly smaller than the outer diameter dimension of the iron core 10, and the iron core 10 is fastened to the inner circumferential surface 61i along the axial X by press fitting or shrink fitting, etc. In this case, both end faces of the body 61 in the axial X direction are positioned so that they protrude outward in the axial X direction beyond the iron core 10.

The pair of lid portions 62 each have an attachment surface 62a that fits tightly against the end surface of the corresponding side in the axial X direction of the body portion 61. Furthermore, when each attachment surface 62a is fixed to the end surface of the body portion 61 in the axial X direction, the pair of lid portions 62 also have a fitting surface (end surface) 62b that fits tightly against the corresponding second sealing portion 32 around the entire circumference from the outside in the axial X direction.

As a result, annular spaces H1 and H2 are formed on both outer sides of the iron core 10 in the direction of the axis X, sealed liquid-tight by the body 61, the pair of lid portions 62, and the pair of second sealing portions 32. As shown in Figure 2, spaces H1 and H2 are connected to each other via the flow paths defined in each slot S by the first sealing portions 31. In other words, the iron core 10 and the coil 20 wound around the iron core 10 are housed in a single sealed space consisting of spaces H1 and H2 and the flow paths in each slot S.

An inlet 6i, which is connected to an external pump (not shown) and allows a refrigerant such as oil to be poured into the space H1 side of the body 61. On the other hand, an outlet 6o, which discharges the refrigerant in the space H2 to the outside, is provided on the space H2 side of the body 61, and the outlet 6o is connected to a heat exchanger (not shown) that supplies the refrigerant to the external pump.
This allows the refrigerant to be filled and circulated within the sealed space that houses the coil 20, so the electric motor 100 is configured to be able to cool the coil 20 within the sealed space.

The operation of the stator 1 and the electric motor 100 according to this embodiment configured as described above will be described below.
In the following, a method for cooling the coil 20 provided in the stator 1 of the electric motor 100 will be described as an example.

To cool the coil 20, an external pump is first connected to the inlet 6i of the housing 6 of the electric motor 100, and refrigerant is injected into the sealed space formed by the housing 6 and iron core 10 that contains the coil 20. The injected refrigerant fills space H1 and then flows into space H2 through the flow paths formed in each slot S. The inflowing refrigerant then fills space H2 and is sent to an external heat exchanger via the outlet 6o. The refrigerant sent to the heat exchanger is cooled and returned to the pump, where it is again injected into the sealed space through the inlet 6i by the pump.

This allows the refrigerant to flow from the inlet 6i side toward the outlet 6o side within the sealed space formed by the iron core 10 and housing 6 and containing the coil 20. In other words, by allowing the temperature-adjusted refrigerant to flow while in contact with the coil 20 and the surfaces within each slot S, heat generated in the coil 20 and iron core 10 can be recovered, preventing excessive heat generation in the stator 1 and electric motor 100.

Furthermore, in this case, as shown in Figure 4, the first sealing portion 31 is formed to match the opening shape of the opening 14 of each slot S, so each opening 14 can be sealed without any gaps. Therefore, it is possible to more reliably prevent the refrigerant used to cool the coil 20 from leaking from within each slot S toward the rotor 5.

Furthermore, the second sealing portions 32 that seal between both end surfaces of the tip of each tooth 12 in the direction of the axis X and the contact surfaces 62b of the pair of lid portions 62 are formed integrally with the first sealing portions 31 that are fixed in close contact with the inside of each opening 14. As a result, the bottom surfaces 32b of the second sealing portions 32 can be maintained in close contact with both end surfaces of the tip of each tooth 12 in the direction of the axis X.

Furthermore, by insert molding the second sealing portion 32 into the first sealing portion 31, as shown in FIG. 5, even if the dimensions of each tooth 12 in the direction of axis X are uneven, no gaps will form between each tooth 12 and the second sealing portion 32. In other words, even if the bottom surface 32b of the second sealing portion 32 and some teeth 12 are not in close contact due to variations in the dimensions of each tooth 12 in the direction of axis X, the resin material of the first sealing portion 31 can be poured into the gap and positioned there.

As a result, the portions of the bottom surface 32b of the second sealing portion 32 that come into contact with both end surfaces of the teeth 12 in the axis X direction can prevent the refrigerant from leaking from the spaces H1, H2 due to their tight contact with each other. On the other hand, the portions of the bottom surface 32b of the second sealing portion 32 that do not come into contact with either end surface of the teeth 12 in the axis X direction can prevent the refrigerant from leaking from the spaces H1, H2 due to their integral connection with the resin material of the first sealing portion 31.
In this way, by integrally forming the first sealing portion 31 and the second sealing portion 32 that seal the sealed space that houses the coil 20, the sealed space can be sealed more reliably, and leakage of the refrigerant to the outside can be prevented.

In this embodiment, the bottom surface 32b of the second sealing portion 32 is in direct contact with both end surfaces in the direction of the axis X of the tip of each tooth 12. Alternatively, the resin material of the first sealing portion 31 may be continuously disposed in the circumferential direction around the axis X between the second sealing portion 32 and both end surfaces in the direction of the axis X of the tip of each tooth 12.
6, a recess 32c extending around the entire periphery may be provided on the bottom surface 32b of the second sealing portion 32. In this case, the second sealing portion 32 is insert-molded into the first sealing portion 31, so that the resin material of the first sealing portion 31 also fills the recess 32c.

That is, the second sealing portion 32 can be fixed in close contact with both end surfaces of the tip of each tooth 12 in the direction of the axis X, with the resin material of the first sealing portion 31 filled in the recess 32 c interposed therebetween. This allows for more reliable sealing between the second sealing portion 32 and both end surfaces of each tooth 12 in the direction of the axis X.
Furthermore, at the connection portion between the first sealing portion 31 and the second sealing portion 32, the contact area can be increased by the amount of the recess 32c, making the connection between the first sealing portion 31 and the second sealing portion 32 stronger.

Furthermore, instead of the recess 32c having a rectangular cross section as shown in Figure 6, the cross section of the recess 32c may have a shape in which the opening of the recess 32c narrows, such as a dovetail groove. This improves the holding force that tightly adheres the first sealing portion 31 to the second sealing portion 32 against the contraction force that occurs when the resin hardens.

In addition, in this embodiment, for example, as shown in Figure 7, the bottom surface 32b of the second sealing portion 32 may be formed as a rough surface having unevenness of the same size as or larger than both end surfaces of each tooth 12 in the direction of the axis X.
As a result, a small gap is formed between the bottom surface 32b and the opposing end surface of each tooth 12 due to the unevenness of the bottom surface 32b. Therefore, in this case as well, the resin material of the first sealing portion 31 can be disposed between the second sealing portion 32 and each tooth 12, ensuring more reliable adhesion between the two. Furthermore, by roughening the bottom surface 32b of the second sealing portion 32, the contact area with the resin material of the first sealing portion 31 is increased, which has the advantage of improving adhesion between the two. Furthermore, if the gaps formed by the unevenness of the rough surface are continuous in the circumferential direction, the resin material of the first sealing portion 31 filled in those gaps is also continuously disposed in the circumferential direction, further improving sealing performance.

In the present embodiment, the first sealing portion 31 is formed by filling a resin material at a position that closes the opening 14 of each slot S. Alternatively, the first sealing portion 31 may be formed to integrally cover the opening 14 of each slot S and the inner circumferential surface of the tip of each tooth 12.
For example, the inner surface 31i of the first sealing portion 31 in the embodiment shown in Figure 4 may be positioned radially inward from the inner surfaces of each tooth 12, within a range that does not contact the main body portion 51 of the rotor 5.

Furthermore, in this embodiment, the inner peripheral surface 32i and outer peripheral surface 32o of the second sealing portion 32 on both sides in the thickness direction of the core 10 are positioned at the same radial position as the inner peripheral surface 31i and outer peripheral surface 31o of the first sealing portion 31, respectively. Alternatively, the radial position of the inner peripheral surface 32i of at least one second sealing portion 32 does not have to coincide with the inner peripheral surface 31i of the first sealing portion 31, as long as the bottom surface 32b of the second sealing portion 32 is connected to the end face of the first sealing portion 31 in the axial X direction. Similarly, the radial position of the outer peripheral surface 32o of at least one second sealing portion 32 does not have to coincide with the outer peripheral surface 31o of the first sealing portion 31, within the range where the bottom surface 32b of the second sealing portion 32 is connected to the end face of the first sealing portion 31 in the axial X direction.

Furthermore, in this embodiment, the first sealing portion 31 and the second sealing portion 32, which are made of different materials, are integrated by insert molding. Alternatively, the first sealing portion 31 and the second sealing portion 32 may be formed by integral molding using the same material.

In this case, the first sealing portion 31 and the second sealing portion 32 are formed into a single, integrally molded product, eliminating the boundary between them, thereby more reliably sealing the enclosed space in which the coil 20 is housed. Furthermore, this prevents an increase in the number of parts in the sealing member 30, improving the manufacturability of the stator 1 and the electric motor 100 and reducing manufacturing costs.

In addition, in this embodiment, the first sealing portion 31 is formed from a resin material, but the material from which the first sealing portion 31 is formed is not limited to this. Any material can be selected for the first sealing portion 31, as long as it can be filled in a position that covers each opening 14, conforming to the shape of the opening, and can be used to insert-mold the second sealing portion 32.

Furthermore, in this embodiment, the second sealing portion 32 is formed from a resin material different from that of the first sealing portion 31, but the material of the second sealing portion 32 is not limited to this. For example, the second sealing portion 32 may be formed from an elastically deformable material such as rubber or silicone, or a non-magnetic metal material such as stainless steel or an aluminum alloy. Furthermore, if the effect on the magnetic flux used to drive the rotor 5 can be tolerated, a magnetic material may be used as the material of the second sealing portion 32.

In the electric motor 100 according to this embodiment, a seal member 70 may be disposed between the contact surface 62b of the lid portion 62 of the housing 6 and the second sealing portion 32, as shown in FIG.
In this case, for example, a groove 62g having a semicircular cross section and extending around the entire circumference is provided on the contact surface 62b of the lid portion 62. Similarly, a groove 32g having a semicircular cross section and extending around the entire circumference is provided on the surface of the second sealing portion 32 that comes into contact with the contact surface 62b.

As a result, a groove with a circular cross section that extends around the entire circumference is formed between the contact surface 62b of the lid portion 62 and the second sealing portion 32, and a sealing member 70 such as an O-ring can be fitted into the groove, thereby more reliably sealing the gap between the lid portion 62 and the second sealing portion 32.
8, the grooves 62g and 32g are respectively provided in both the lid portion 62 and the second sealing portion 32. Alternatively, if the sealing member 70 can be disposed between the lid portion 62 and the second sealing portion 32, one of the grooves 62g and 32g may be omitted.

Furthermore, while the electric motor 100 according to this embodiment is exemplified as a rotary motor in which the rotor 5 is disposed radially inside the iron core 10 and rotates around the axis X, the electric motor 100 is not limited to this. For example, the electric motor 100 may be an outer rotor type in which the rotor 5 is disposed radially outside the iron core 10. Furthermore, the electric motor 100 may be a linear motor or the like that drives a rotor in a direction along a predetermined axis.

Furthermore, in this embodiment, the inlet 6i and the outlet 6o are provided in the body portion 61 of the housing 6. Alternatively, both or either of the inlet 6i and the outlet 6o may be provided in the lid portion 62 of the housing 6.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the invention, or without departing from the idea and intent of the present invention as derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these.

The following additional notes are provided regarding the above-described embodiment and modifications.
(Appendix 1)
a stator comprising: a back yoke; an iron core having a plurality of teeth protruding from the back yoke toward a movable member and arranged at intervals along the drive direction of the movable member; a plurality of coils wound around each of the teeth; and a sealing member that liquid-tightly seals each slot formed between adjacent teeth, the sealing member comprising: a first sealing portion arranged in the gap between the tips of adjacent teeth; and a second sealing portion arranged on at least one side of the teeth in the thickness direction, in a position covering at least the thickness-wise end faces of the tip sides of all of the teeth and the thickness-wise end faces of all of the first sealing portions, and which can be tightly fitted to a housing that accommodates the iron core and the coils, wherein the first sealing portion and the second sealing portion are integrally formed.
(Appendix 2)
2. The stator according to claim 1, wherein the first sealing portion covers an end surface of each of the teeth on the mover side.
(Appendix 3)
The stator described in Appendix 1 or Appendix 2, wherein the back yoke is formed in a cylindrical shape with the axis as a center axis and surrounds the mover that rotates around the axis, each of the teeth protrudes radially toward the mover, and the second sealing portion is formed in a circular ring shape centered on the axis.
(Appendix 4)
4. The stator according to claim 1, wherein the second sealing portion is integrated with the first sealing portion by insert molding.
(Appendix 5)
5. The stator according to claim 4, wherein a recess that continues along the driving direction is provided on an end surface of the second sealing portion on the tooth side.
(Appendix 6)
5. The stator according to claim 4, wherein the end surface of the second sealing portion on the teeth side is a rough surface having a plurality of concave and convex portions.
(Appendix 7)
4. The stator according to claim 1, wherein the first sealing portion and the second sealing portion are formed by integral molding using the same material.
(Appendix 8)
8. An electric motor comprising: the stator according to any one of Supplementary Note 1 to Supplementary Note 7; the mover arranged with a predetermined gap between it and the stator; and the housing that accommodates the iron core and the coil.
(Appendix 9)
9. The electric motor described in Appendix 8, wherein a groove is provided on at least one of an end surface of the second sealing portion that comes into close contact with the housing and an end surface of the housing that comes into close contact with the second sealing portion, into which a seal member that seals between the second sealing portion and the housing can be placed.

1 Stator 5 Rotor (moving element)
6 Housing 10 Iron core 11 Back yoke 12 Teeth 20 Coil 30 Sealing member 31 First sealing portion 32 Second sealing portion 32b Bottom surface (end surface)
32c: recess 32g: groove 62b: contact surface (end surface)
62g Groove 70 Seal member 100 Motor S Slot X Axis

Claims (9)

a core including a back yoke and a plurality of teeth protruding from the back yoke toward a mover and arranged at intervals along a drive direction of the mover;
a plurality of coils wound around each of the teeth;
a sealing member that liquid-tightly seals each slot formed between the adjacent teeth,
The sealing member is
a first sealing portion disposed in a gap between the tips of the adjacent teeth;
a second sealing portion disposed on at least one side in the thickness direction of the teeth at a position covering end faces in the thickness direction of at least the tip ends of all the teeth and end faces in the thickness direction of all the first sealing portions, and capable of being tightly attached to a housing that accommodates the iron core and the coil;
A stator in which the first sealing portion and the second sealing portion are integrally formed. The stator described in claim 1, wherein the first sealing portion covers the end surface of each tooth facing the mover. the back yoke is formed in a cylindrical shape with the axis line as a center axis and surrounding the mover that rotates about the axis line,
Each of the teeth protrudes radially toward the mover,
3. The stator according to claim 1, wherein the second sealing portion is formed in an annular shape centered on the axis. A stator as described in any one of claims 1 to 3, wherein the second sealing portion is integrated with the first sealing portion by insert molding. The stator described in claim 4, wherein a continuous recess is provided along the drive direction on the end surface of the second sealing portion facing the teeth. A stator as described in claim 4, wherein the end surface of the second sealing portion facing the teeth is a rough surface having multiple irregularities. A stator as described in any one of claims 1 to 3, wherein the first sealing portion and the second sealing portion are formed by integral molding using the same material. The stator according to any one of claims 1 to 7;
the mover disposed with a predetermined gap between it and the stator;
an electric motor comprising the housing that accommodates the iron core and the coil; The electric motor described in claim 8, wherein a groove is provided on at least one of the end surface of the second sealing portion that comes into close contact with the housing and the end surface of the housing that comes into close contact with the second sealing portion, in which a seal member that seals between the second sealing portion and the housing can be placed.