Foamed insulating material

Abstract

This invention provides a technology for suitably improving the insulation between the stator core and the coil. [Solution] The foamed insulating member is placed between the stator core and the coil to insulate the stator core from the coil. The foamed insulating member comprises an intermediate layer, a first foamed layer provided on the first surface of the intermediate layer and positioned opposite the stator core, and a second foamed layer provided on the second surface opposite the first surface of the intermediate layer and positioned opposite the coil. The foaming agent content in the second foamed layer is higher than the foaming agent content in the first foamed layer.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a foamed insulating member for insulating between a stator core and a coil.

Background Art

[0002] Patent Document 1 discloses a stator including a stator core and a coil inserted into a slot of the stator core. An insulating member is attached to the inner surface of the slot to insulate between the stator core and the coil inserted into the slot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the adhesion between the insulating member, the coil, and the stator core is ensured by pressing the slot from both sides in the circumferential direction. However, in the technology of Patent Document 1, the adhesion is not sufficient, and particularly, an unnecessary space is likely to occur between the insulating member and the coil. When such a space occurs, problems such as a decrease in insulation performance may occur. This specification provides a technology for suitably improving the insulation between the stator core and the coil.

Means for Solving the Problems

[0005] The technology disclosed herein is embodied in a foamed insulating member disposed between a stator core and a coil to insulate the stator core from the coil. The foamed insulating member comprises an intermediate layer, a first foamed layer provided on a first surface of the intermediate layer and positioned opposite the stator core, and a second foamed layer provided on a second surface of the intermediate layer opposite to the first surface and positioned opposite the coil. The foaming agent content in the second foamed layer is higher than the foaming agent content in the first foamed layer.

[0006] The foamed insulating member described above is used by interposing it between the stator core and the coil, and then foaming each foam layer. As a result, the space between the intermediate layer and the stator core, and the space between the intermediate layer and the coil, are filled with the foamed foam layers. Furthermore, the space on the coil side of the foamed insulating member has a more complex shape compared to the space on the stator core side of the foamed insulating member, due to the coil being arranged in multiple layers. However, in the foamed insulating member described above, the foaming agent content in the second foam layer is higher than that in the first foam layer. That is, the second foam layer is foamed to a greater degree than the first foam layer. Therefore, the space between the intermediate layer and the coil can be suitably filled with the foamed second foam layer. As described above, this foamed insulating member can suitably fill the space between the stator core and the coil, improving the insulation between them. [Brief explanation of the drawing]

[0007] [Figure 1] A longitudinal cross-sectional view showing the stator configuration. [Figure 2] Cross-sectional view along line II-II in Figure 1. [Figure 3] A schematic diagram showing the structure of a foamed insulating material. [Modes for carrying out the invention]

[0008] (Examples) Referring to the drawings, a stator 20 comprising the foamed insulating member 10 of the embodiment will be described. The stator 20, together with the rotor located on the inner diameter side of the stator 20, constitutes a motor. Although not particularly limited, the motor can be used in electric vehicles as a prime mover to drive the wheels. Electric vehicles include, for example, battery electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and fuel cell electric vehicles.

[0009] As shown in Figures 1 and 2, the stator 20 comprises a stator core 22 and a plurality of coils 28 wound around the stator core 22. The stator core 22 is made of a soft magnetic material. In this embodiment, the stator core 22 has a structure in which a plurality of electromagnetic steel sheets are laminated. The stator core 22 has a core back 24 that extends cylindrically along the axial direction and a plurality of teeth 26 provided on the inner circumferential surface 24a of the core back 24. As shown in Figure 2, the plurality of teeth 26 are arranged at equal intervals along the circumferential direction. Each tooth 26 protrudes from the inner circumferential surface 24a of the core back 24 toward the central axis. Between the teeth 26, a plurality of slots 27 are formed, which are spaces in which a portion of the coils 28 are housed. Each slot 27 extends radially along the stator core 22. The plurality of slots 27 are arranged at equal intervals along the circumferential direction.

[0010] The coil 28 is wound around the teeth 26 of the stator core 22. As shown in Figure 1, the coil 28 has multiple segment coils 30. The coil 28 is formed by connecting multiple segment coils 30. The segment coils 30 are conductors 32 made of metal or alloy material, and are covered with a coil coating 34 made of insulating material, except for their ends.

[0011] The segment coil 30 is inserted into the slot 27 from one axial end of the stator core 22 and is electrically connected to another segment coil 30 inserted into the slot 27 from the other axial end of the stator core 22 via a connecting member 36. The connecting member 36 is conductive and is a cylindrical member that electrically connects the two segment coils 30 within the slot 27. The conductor 32 of one segment coil 30 is fitted into one end of the connecting member 36, and the conductor 32 of the other segment coil 30 is fitted into the other end of the connecting member 36, thereby electrically connecting the two segment coils 30.

[0012] As shown in Figure 2, a foamed insulating member 10 is placed in the slot 27. The foamed insulating member 10 is placed between the stator core 22 and the coil 28. The foamed insulating member 10 comprises an intermediate layer 12, a first foamed layer 14, and a second foamed layer 16. When the stator 20 is assembled, the first foamed layer 14 and the second foamed layer 16 are already foamed. Therefore, the space between the intermediate layer 12 and the stator core 22 is filled with the first foamed layer 14, and the space between the intermediate layer 12 and the coil 28 is filled with the second foamed layer 16. Note that the foamed insulating member 10 is not shown in Figure 1. Below, with reference to Figure 3, the foamed insulating member 10 in the state before the first foamed layer 14 and the second foamed layer 16 are foamed (i.e., before the stator 20 is assembled) will be described.

[0013] The intermediate layer 12 is a substrate for holding the first foamed layer 14 and the second foamed layer 16. The intermediate layer 12 is made of, for example, a resin. Examples of resins include polyphenylene sulfide. The thickness of the intermediate layer 12 is not particularly limited, but can be, for example, about 100 μm.

[0014] The first foam layer 14 is provided on the first surface 12a of the intermediate layer 12. The first foam layer 14 is composed of, for example, a plurality of beads containing a foaming agent. The thickness of the first foam layer 14 is not particularly limited, but can be, for example, about 35 μm.

[0015] The second foam layer 16 is provided on the second surface 12b of the intermediate layer 12. The second surface 12b is the surface opposite to the first surface 12a of the intermediate layer 12. The second foam layer 16 is composed of, for example, a plurality of beads containing a foaming agent. In this embodiment, the thickness of the second foam layer 16 is greater than the thickness of the first foam layer 14. The thickness of the second foam layer 16 is not particularly limited, but can be, for example, about 55 μm. However, the thickness of the second foam layer 16 does not have to be greater than the thickness of the first foam layer 14. The content of the foaming agent in the second foam layer 16 is higher than the content of the foaming agent in the first foam layer 14.

[0016] When assembling the stator 20, the foamed insulating member 10 shown in Figure 3 is placed along the inner surface of the slot 27 of the stator core 22, and then each segment coil 30 is inserted into the slot 27. That is, the foamed insulating member 10 is positioned so that it is interposed between the inner surface of the slot 27 and the segment coil 30. Subsequently, the stator 20 is heated with steam or the like to foam the first foamed layer 14 and the second foamed layer 16. This fills the space between the stator core 22 and the segment coil 30.

[0017] As shown in Figure 2, the space on the coil 28 side of the intermediate layer 12 has a more complex shape compared to the space on the stator core 22 side of the intermediate layer 12, due to the coil 28 being arranged in multiple layers. However, in the foamed insulating member 10 of this embodiment, the thickness of the second foamed layer 16 is greater than the thickness of the first foamed layer 14, so the second foamed layer 16 has a sufficient volume to fill the space on the coil 28 side. Furthermore, the foaming agent content in the second foamed layer 16 is higher than the foaming agent content in the first foamed layer 14. That is, the second foamed layer 16 is more foamed than the first foamed layer 14. Therefore, the space between the intermediate layer 12 and the coil 28 can be suitably filled with the foamed second foamed layer 16. As described above, the foamed insulating member 10 of this embodiment can suitably fill the space between the stator core 22 and the coil 28, improving the insulation between the two. Furthermore, since the second foamed layer 16 has a higher foaming agent content than the first foamed layer 14, the porosity of the second foamed layer 16 after foaming is higher than that of the first foamed layer 14 after foaming. [Explanation of Symbols]

[0018] 10: Foamed insulating material, 12: Intermediate layer, 12a: First surface, 12b: Second surface, 14: First foamed layer, 16: Second foamed layer, 20: Stator, 22: Stator core, 24: Core back, 26: Teeth, 27: Slot, 28: Coil, 30: Segment coil, 32: Conductor, 34: Coil coating, 36: Connecting member

Claims

[Claim 1] A foamed insulating member disposed between the stator core and the coil, for insulating the space between the stator core and the coil, The middle class, A first foamed layer is provided on the first surface of the intermediate layer and is positioned opposite the stator core, A second foamed layer is provided on the second surface of the intermediate layer, which is located opposite to the first surface, and is positioned opposite the coil, Equipped with, The content of the foaming agent in the second foam layer is higher than the content of the foaming agent in the first foam layer. Foamed insulating material.

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