Stator

Abstract

A stator according to the present disclosure is provided with: a stator core which is configured in a cylindrical shape by laminating a plurality of electromagnetic steel sheets, and in which a flow path through which a refrigerant flows extends in the axial direction; and gaskets which are respectively disposed between adjacent electromagnetic steel sheets when the orientation of at least one electromagnetic steel sheet among the adjacent electromagnetic steel sheets is reversed in the axial direction, or between adjacent electromagnetic steel sheets when at least one electromagnetic steel sheet among the adjacent electromagnetic steel sheets is rotated in the circumferential direction, in an elastically deformed state so as to contract along the axial direction. The electromagnetic steel sheets have refrigerant holes that define the flow path, and the gaskets have communication holes that allow the refrigerant holes in the adjacent electromagnetic steel sheets to communicate with one another.

Description

Stator

[0001] The present disclosure relates to a stator.

[0002] The stator may include a cylindrical stator core having a flow path through which a refrigerant flows. When the stator core is composed of a plurality of electromagnetic steel sheets laminated together, the electromagnetic steel sheets have refrigerant holes that define the flow path. When a plurality of electromagnetic steel sheets are laminated, the refrigerant holes of adjacent electromagnetic steel sheets communicate with each other, thereby forming a flow path that penetrates in the axial direction of the stator core in the stator core.

[0003] Thus, when the stator core is composed of a plurality of electromagnetic steel sheets, the adjacent electromagnetic steel sheets are adhered to each other, or varnish or sealing resin is applied to the plurality of laminated electromagnetic steel sheets, so that the refrigerant in the flow path does not leak out from the gaps between the adjacent electromagnetic steel sheets. Also, when the stator core is composed of a plurality of electromagnetic steel sheets, gaskets may be arranged between all adjacent electromagnetic steel sheets so that the refrigerant in the flow path does not leak out from the gaps between the adjacent electromagnetic steel sheets.

[0004] Japanese Patent Application Laid-Open No. 2017-169249

[0005] The electromagnetic steel sheets have warpage. When a plurality of electromagnetic steel sheets are laminated, in order to reduce the influence of warpage in the entire plurality of laminated electromagnetic steel sheets, the direction of the electromagnetic steel sheets is reversed in the axial direction, or the electromagnetic steel sheets are rotated in the circumferential direction. A gap is likely to form between the reversed electromagnetic steel sheet and the adjacent electromagnetic steel sheet, or between the circumferentially rotated electromagnetic steel sheet and the adjacent electromagnetic steel sheet. In a stator core having such a configuration, for example, when a plurality of laminated electromagnetic steel sheets are impregnated with varnish, the above-described gap is sealed by the varnish.

[0006] When a stator core impregnated with varnish is heated or cooled, the varnish sealing the aforementioned gap may not be able to keep up with the expansion and contraction of the stator core as it expands and contracts in the axial direction. If the varnish sealing the aforementioned gap cannot keep up with the expansion and contraction of the stator core, the seal provided by the varnish will weaken. If the seal provided by the varnish is weak, the seal may be destroyed when pressure is applied to the aforementioned gap by the refrigerant flowing through the flow path. If the seal provided by the varnish is destroyed, the refrigerant in the flow path will leak to the outside through the gap between adjacent electrical steel sheets.

[0007] When gaskets are placed between all adjacent electrical steel sheets, the motor has multiple gaskets that do not contribute to the output. Therefore, a motor with gaskets between all adjacent electrical steel sheets can stack fewer electrical steel sheets at a predetermined interval compared to a motor without gaskets between adjacent sheets, resulting in reduced motor output and torque. A motor with gaskets between all adjacent electrical steel sheets incurs gasket costs and increases the manufacturing time of the stator.

[0008] To address the aforementioned problems, there is a need for a stator with a simple configuration that can reliably seal gaps even when there are large gaps between adjacent electrical steel sheets, and that can suppress a reduction in the number of electrical steel sheets that can be laminated.

[0009] The stator of this disclosure comprises a stator core formed by stacking a plurality of electromagnetic steel sheets in a cylindrical shape, with a flow path for a refrigerant extending in the axial direction, and a gasket that is elastically deformed to shrink along the axial direction, positioned between adjacent electromagnetic steel sheets when at least one of the adjacent electromagnetic steel sheets is rotated in the axial direction, or between adjacent electromagnetic steel sheets when at least one of the adjacent electromagnetic steel sheets is rotated in the circumferential direction, wherein the electromagnetic steel sheets have refrigerant holes that define the flow path, and the gasket has communication holes that connect the refrigerant holes of adjacent electromagnetic steel sheets.

[0010] This is a schematic diagram showing the usage state of a stator according to one embodiment of the present invention. This is a front view showing an electrical steel sheet used in a stator according to one embodiment of the present invention. This is a front view showing a gasket used in a stator according to one embodiment of the present invention. This is an explanatory diagram showing the stator core of a stator according to one embodiment of the present invention in a contracted state. This is an explanatory diagram showing the stator core of a stator according to one embodiment of the present invention in an extended state. This is a longitudinal cross-sectional view showing another example of a gasket used in a stator according to one embodiment of the present invention, showing a part of the gasket.

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The stator 1 according to this embodiment will be described with reference to Figures 1 to 3. The stator 1 is used together with a rotor in an electric motor that provides power to rotating machinery. Note that the device in which the stator 1 is used is not limited to an electric motor, but may be a generator, for example. The stator 1 comprises a stator core 2 and a gasket 3. Hereinafter, the axial direction of the stator 1 will be defined as axial direction J1.

[0012] The stator core 2 is cylindrical with openings at both ends in the axial direction J1. In the illustrated example, the outer shape of the stator core 2 is square, and the inner bore of the stator core 2 is circular in cross-section. The outer shape of the stator core 2 is not limited to a square, but can be polygonal. The stator core 2 has a plurality of teeth (not shown) around which a coil (not shown) is wound. The plurality of teeth protrude radially inward from the inner circumferential surface of the stator core 2. The plurality of teeth are arranged in the circumferential direction of the inner circumferential surface of the stator core 2. Inwardly opening slots (not shown) are formed between adjacent teeth. The coil wound on the teeth passes through the slots. The stator core 2 has a flow path 4 through which a refrigerant flows. The flow path 4 is a through-hole with a circular cross-section and extends in the axial direction J1. The refrigerant flowing through the flow path 4 is a liquid, typically cooled water.

[0013] A pair of brackets 5, 5 are positioned at both ends of the stator core 2 along the axial direction J1. Of the pair of brackets 5, 5, one bracket 5 is positioned at one end of the axial direction J1 of the stator core 2, and the other bracket 5 is positioned at the other end of the axial direction J1 of the stator core 2. The stator core 2 and the pair of brackets 5, 5 are fastened together by fastening members 6. Therefore, the stator core 2 has fastening through holes 7 through which the fastening members 6 pass. The fastening through holes 7 penetrate the axial direction J1 of the stator core 2. In the illustrated example, the fastening member 6 is a bolt, which is screwed into a threaded hole provided in the other bracket 5.

[0014] The stator core 2 is constructed by laminating multiple electromagnetic steel sheets 8. As shown in Figure 2, the electromagnetic steel sheet 8 is a rectangular plate in front view and has a hole 9 in the center that defines the inner hole of the stator core 2. The hole 9 is circular in front view and penetrates the stator core 2 in the axial direction J1. The electromagnetic steel sheet 8 has multiple teeth portions 10 on the inner circumferential surface of the hole 9. The teeth portions 10 protrude radially inward from the inner circumferential surface of the hole 9. The multiple teeth portions 10 are arranged in the circumferential direction of the hole 9. In the illustrated example, the teeth portions 10 extend so as they taper towards the radially inward direction of the hole 9.

[0015] The electromagnetic steel sheet 8 has refrigerant holes 11 that define the flow path 4. The refrigerant holes 11 are circular in front view and penetrate the axial direction J1 of the stator core 2. In the illustrated example, the electromagnetic steel sheet 8 has four refrigerant holes 11. The four refrigerant holes 11 are located at the four corners of the electromagnetic steel sheet 8. The number and position of the refrigerant holes 11 can be changed as appropriate. The electromagnetic steel sheet 8 has fastening holes 12 that define fastening insertion holes 7. The fastening holes 12 do not bulge outward from the refrigerant holes 11 and are therefore not continuous with the refrigerant holes 11. That is, the fastening holes 12 do not communicate with the refrigerant holes 11. The fastening holes 12 are circular in front view and penetrate the axial direction J1 of the stator core 2. In the illustrated example, the electromagnetic steel sheet 8 has two fastening holes 12 that sandwich each refrigerant hole 11. The number and position of the fastening holes 12 can be changed as appropriate. The fastening hole 12 is preferably adjacent to the refrigerant hole 11. Here, "adjacent" means, for example, that there is no through hole and / or recess between them.

[0016] The gasket 3 is positioned between predetermined adjacent electrical steel sheets 8, 8. The gasket 3 is elastically deformable so as to shrink along the axial direction J1 of the stator core 2. As shown in Figure 3, the gasket 3 is a rectangular rubber plate in front view and has a hole 13 in the center that defines the inner hole of the stator core 2. The hole 13 is circular in front view and penetrates the axial direction J1 of the stator core 2. The gasket 3 does not have teeth that have the same function as the teeth 10 of the electrical steel sheet 8. That is, the gasket 3 does not have a portion that protrudes radially inward from the inner circumferential surface of the hole 13.

[0017] The gasket 3 has communication holes 14 that connect the refrigerant holes 11, 11 of adjacent electrical steel sheets 8, 8. The communication holes 14 are circular in front view and penetrate through to the axial direction J1 of the stator core 2. In the illustrated example, the gasket 3 has four communication holes 14. The four communication holes 14 are located at the four corners of the gasket 3. The number and position of the communication holes 14 can be changed as appropriate. The gasket 3 also has through holes 15 that connect the fastening holes 12, 12 of adjacent electrical steel sheets 8, 8. The through holes 15 do not bulge outward from the communication holes 14 and are therefore not continuous with the communication holes 14. That is, the through holes 15 do not communicate with the communication holes 14. The through holes 15 are circular in front view and penetrate through to the axial direction J1 of the stator core 2. In the illustrated example, the gasket 3 has two through holes 15 flanking each communication hole 14. The number and position of the through holes 15 can be changed as appropriate. Preferably, the through holes 15 are adjacent to the communication holes 14. "Adjacent" here means, for example, that there are no through holes and / or recesses between them.

[0018] Next, the assembly of the stator 1 according to this embodiment will be described. As shown in Figure 1, the stator core 2 is formed by stacking a plurality of electromagnetic steel sheets 8 in the axial direction J1 of the stator core 2. When stacking a plurality of electromagnetic steel sheets 8, generally, at least one of the adjacent electromagnetic steel sheets 8, 8 is rotated in the axial direction J1 of the stator core 2, or at least one of the adjacent electromagnetic steel sheets 8, 8 is rotated in the circumferential direction of the stator core 2.

[0019] Here, as mentioned above, the locations where the electromagnetic steel sheet 8 is inverted or rotated are defined as predetermined locations. The stator core 2 has three predetermined locations, but is not limited to these; it only needs to have at least one predetermined location. If the stator core 2 has one predetermined location, the predetermined location may be a location where the electromagnetic steel sheet 8 is inverted, as mentioned above, or a location where the electromagnetic steel sheet 8 is rotated, as mentioned above. If the stator core 2 has multiple predetermined locations, all predetermined locations may be locations where the electromagnetic steel sheet 8 is inverted, as mentioned above, or locations where the electromagnetic steel sheet 8 is rotated, as mentioned above. If the stator core 2 has multiple predetermined locations, the multiple predetermined locations may be a combination of locations where the electromagnetic steel sheet 8 is inverted and locations where the electromagnetic steel sheet 8 is rotated, as mentioned above.

[0020] When at least one of the adjacent electromagnetic steel sheets 8, 8 is rotated in the axial direction J1 of the stator core 2, a gasket 3 is placed between the adjacent electromagnetic steel sheets 8, 8. Alternatively, when at least one of the adjacent electromagnetic steel sheets 8, 8 is rotated in the circumferential direction of the stator core 2, a gasket 3 is placed between the adjacent electromagnetic steel sheets 8, 8. The predetermined location can also be described as the location where the gasket 3 is placed.

[0021] In this way, multiple electromagnetic steel sheets 8 and gaskets 3 are stacked, forming a flow path 4 that penetrates in the axial direction J1 and a fastening insertion hole 7 that penetrates in the axial direction J1 in the stator core 2. The flow path 4 is formed when the refrigerant holes 11, 11 of adjacent electromagnetic steel sheets 8, 8 communicate with each other. At the predetermined location mentioned above, the flow path 4 is formed when the refrigerant holes 11, 11 of adjacent electromagnetic steel sheets 8, 8 communicate with each other by a communication hole 14. The fastening insertion hole 7 is formed when the fastening holes 12, 12 of adjacent electromagnetic steel sheets 8, 8 communicate with each other. At the predetermined location mentioned above, the fastening insertion hole 7 is formed when the fastening holes 12, 12 of adjacent electromagnetic steel sheets 8, 8 communicate with each other by a through hole 15.

[0022] Multiple electromagnetic steel sheets 8 and gaskets 3 are laminated together, so that the teeth portions 10, 10 of adjacent electromagnetic steel sheets 8, 8 are laminated together in the axial direction J1 of the stator core 2. As a result, teeth are formed on the stator core 2 that protrude from the inner circumferential surface of the stator core 2. Coils are wound around the teeth of the stator core 2.

[0023] With multiple electromagnetic steel sheets 8 and gaskets 3 stacked together, the stator core 2 and a pair of brackets 5, 5 are fastened together. Specifically, with one bracket 5 positioned at one end of the axial direction J1 of the stator core 2 and the other bracket 5 positioned at the other end of the axial direction J1 of the stator core 2, the fastening member 6 is screwed into a threaded hole formed in the other bracket 5 via the one bracket 5 and the stator core 2. In this way, the stator core 2 and the pair of brackets 5, 5 are fastened together by the fastening member 6.

[0024] When the stator core 2 is fastened to the pair of brackets 5, 5, the gasket 3 is elastically deformed to shrink along the axial direction J1 of the stator core 2 and positioned between adjacent electrical steel sheets 8, 8 at the predetermined locations mentioned above. In this embodiment, the gasket 3 is positioned between one bracket 5 and one end of the axial direction J1 of the stator core 2, and between the other bracket 5 and the other end of the axial direction J1 of the stator core 2. Therefore, when the stator core 2 is fastened to the pair of brackets 5, 5, the gasket 3 is elastically deformed to shrink along the axial direction J1 of the stator core 2 and positioned between the stator core 2 and the brackets 5. At locations other than the predetermined locations mentioned above, the spaces between adjacent electrical steel sheets 8, 8 are sealed, for example, with varnish, as in the conventional method.

[0025] In the case of the stator 1 of this embodiment, the gasket 3 is placed at the predetermined location on the stator core 2 as described above. At the predetermined location, a gap tends to form between adjacent electromagnetic steel sheets 8, 8. As shown in Figure 4, when the stator core 2 is cooled, the stator core 2 shrinks along the axial direction J1. When the stator core 2 shrinks, the already shrunk gasket 3 shrinks further. In this state, the gasket 3 is trying to return to its original state, and as shown by the white arrows in Figure 4, a force acts in the direction of pushing the electromagnetic steel sheet 8. As shown in Figure 5, when the stator core 2 is heated, the stator core 2 stretches along the axial direction J1. When the stator core 2 stretches, the gasket 3 stretches along the axial direction J1 more than its initial state, but maintains its shrunk state. Therefore, when the stator core 2 is stretched, the gasket 3 is trying to return to its original state, and as shown by the white arrows in Figure 5, a force acts in the direction of pushing the electromagnetic steel sheet 8. Thus, according to the stator 1 of this embodiment, the gasket 3 can follow the expansion and contraction of the stator core 2.

[0026] In the case of the stator 1 of this embodiment, the gasket 3 is placed at a predetermined location. Therefore, according to the stator 1 of this embodiment, the number of gaskets 3 can be reduced compared to the conventional case in which gaskets are placed between all adjacent electromagnetic steel sheets.

[0027] In order to ensure uniformity of magnetic flux flow and uniformity of the axial thickness J1 of the stator core 2, it is preferable to provide as many of the aforementioned predetermined locations as possible in the stator 1. Conventionally, providing many of the aforementioned predetermined locations increases the number of places where refrigerant can leak. In contrast, in the stator 1 of this embodiment, a gasket 3 is used, so even if as many of the aforementioned predetermined locations as possible are provided, refrigerant leakage is less likely to occur.

[0028] In electric motors using stator 1, the thickness of the electromagnetic steel sheets 8 is being reduced in order to lower losses. Consequently, the number of electromagnetic steel sheets 8 used in stator 1 tends to increase. In the stator 1 of this embodiment, since the gasket 3 is placed at the predetermined location mentioned above, the reduction in the number of electromagnetic steel sheets 8 can be suppressed. Therefore, with the stator 1 of this embodiment, the high output of the electric motor can be maintained, and reliable sealing of the refrigerant can be ensured.

[0029] In the case of the stator 1 of this embodiment, the multiple fastening insertion holes 7 are adjacent to the flow path 4. Therefore, with the stator 1 of this embodiment, when the stator core 2 and the bracket 5 are fastened together, it is possible to more reliably prevent the refrigerant in the flow path 4 from leaking out from between the adjacent electromagnetic steel plates 8, 8.

[0030] In the case of the stator 1 of this embodiment, the electromagnetic steel sheet 8 has teeth 10 around which the coil is wound, while the gasket 3 does not have teeth around which the coil is wound. Therefore, according to the stator 1 of this embodiment, when the stator 1 is molded with resin, heat transfer is less likely to be obstructed by the teeth of the gasket 3.

[0031] Next, another example of the gasket 3 used in the stator 1 of this embodiment will be described using Figure 6. Note that components having the same reference numerals as those used in the above embodiment have the same function, and therefore their descriptions may be omitted below.

[0032] The gasket 3 in this modified example has a first rubber piece 16, a second rubber piece 17, and a third metal piece 18. The first piece 16 is plate-shaped and is located on one end of the axial direction J1 of the stator core 2. The second piece 17 is plate-shaped and is located on the other end of the axial direction J1 of the stator core 2. The third piece 18 is plate-shaped and is sandwiched between the first piece 16 and the second piece 17. Thus, the gasket 3 only needs to include a portion made of rubber.

[0033] In the gasket 3 of this modified example, the gasket 3 has a third metal piece 18. Therefore, with the gasket 3 of this modified example, the gasket 3 does not bend even when its thickness is reduced, so it can be easily handled while maintaining watertightness.

[0034] According to at least one embodiment described above, the gasket 3 is placed at the predetermined location mentioned above. Therefore, a stator 1 can be provided that has a simple configuration, can reliably seal gaps even when there are large gaps between adjacent electromagnetic steel sheets 8, 8, and can suppress a reduction in the number of electromagnetic steel sheets 8 that can be laminated.

[0035] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0036] In the above embodiment, gaskets 3 were placed at all of the aforementioned predetermined locations, but it is sufficient to place gaskets 3 at at least one of the aforementioned predetermined locations.

[0037] In the above embodiment, the gasket 3 does not have teeth, but it is not limited to this and may have teeth. In this case, it is preferable that the gasket 3 has the same configuration as the electromagnetic steel sheet 8.

[0038] The following further notes are disclosed regarding the above embodiment. (Note 1) The stator (1) is configured in a cylindrical shape by stacking a plurality of electromagnetic steel sheets (8), and comprises a stator core (2) having a flow path (4) through which a refrigerant flows extending in the axial direction, and a gasket (3) which is elastically deformed to shrink along the axial direction, and is positioned between adjacent electromagnetic steel sheets (8) when at least one of the adjacent electromagnetic steel sheets (8) is rotated in the axial direction, or between adjacent electromagnetic steel sheets (8) when at least one of the adjacent electromagnetic steel sheets (8) is rotated in the circumferential direction, wherein the electromagnetic steel sheets (8) have refrigerant holes (11) that define the flow path (4), and the gasket (3) has communication holes (14) that connect the refrigerant holes (11) of adjacent electromagnetic steel sheets (8).

[0039] (Note 2) In Note 1, the stator (1) has fastening through holes (7) that penetrate in the axial direction through which fastening members (6) that fasten the stator (2) to brackets (5) arranged at both ends of the stator core (2) in the axial direction are passed, the electromagnetic steel sheet (8) has fastening holes (12) that define the fastening through holes (7) and do not communicate with the refrigerant holes (11), and the gasket (3) may have through holes (15) that connect the fastening holes (12) of adjacent electromagnetic steel sheets (8) and do not communicate with the communication holes (14).

[0040] (Note 3) In the stator (1), as described in Note 1 or 2, the electromagnetic steel sheet (8) has teeth (10) around which the coil is wound, and the gasket (3) does not have to have teeth around which the coil is wound.

[0041] 1. Stator 2. Stator core 3. Gasket 4. Flow path 5. Bracket 6. Fastening member 7. Fastening insertion hole 8. Electromagnetic steel sheet 10. Teeth section 11. Coolant hole 12. Fastening hole 14. Communication hole 15. Through hole

Claims

1. A stator comprising: a stator core formed by laminating a plurality of electromagnetic steel sheets into a cylindrical shape, with a flow path for a refrigerant extending in the axial direction; and a gasket that is elastically deformed to shrink along the axial direction, positioned between adjacent electromagnetic steel sheets when at least one of the adjacent electromagnetic steel sheets is rotated in the axial direction, or between adjacent electromagnetic steel sheets when at least one of the adjacent electromagnetic steel sheets is rotated in the circumferential direction, wherein the electromagnetic steel sheets have refrigerant holes defining the flow path, and the gasket has communication holes connecting the refrigerant holes of adjacent electromagnetic steel sheets.

2. The stator according to claim 1, wherein the stator core has fastening through holes that penetrate in the axial direction through which fastening members for fastening the stator core and brackets disposed at both ends of the stator core in the axial direction are passed, the electromagnetic steel sheet has fastening holes that define the fastening through holes and do not communicate with the refrigerant holes, and the gasket has through holes that connect the fastening holes of adjacent electromagnetic steel sheets and do not communicate with the connecting holes.

3. The stator according to claim 1 or 2, wherein the electromagnetic steel sheet has teeth on which the coil is wound, and the gasket does not have teeth on which the coil is wound.

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