Motor stator and motor

Abstract

The present invention relates to a motor stator, comprising a stator core (1) and a stator winding (2); the stator core (1) has a plurality of radially extending conductor slots (11); the stator winding (2) has a plurality of conductor members (21), the conductor members (21) being respectively and axially inserted into the conductor slots (11), so as to form a multilayer structure in the radial direction; insulating spacers (22) are wound on the segments of at least some of the conductor members (21) that are accommodated in the conductor slots (11), wherein the insulating spacers (22) can form in the conductor slots (11) cooling channels between the conductor members (21) and / or between the conductor members and the conductor slots, so as to guide a cooling liquid used for cooling the conductor members (21).

Description

Electric machine stator and electric machine TECHNICAL FIELD

[0001] The present invention relates to the field of electric machines, in particular to a drive electric machine for a vehicle, and in particular to an electric machine stator having an electric machine stator structure for in-slot cooling. BACKGROUND

[0002] In the design of conventional electric machines, the stator structure and cooling scheme are important factors affecting the performance and service life of the electric machine. The stator core is usually composed of a plurality of stacked stator core sheets, and conductor slots are formed in the periphery of the stator core sheets. In the use of conventional electric machine stators, the conductor pieces are prone to performance degradation or damage due to heat accumulation. In order to improve the cooling effect of the electric machine, the prior art uses the method of injecting cooling liquid into the conductor slots for cooling.

[0003] An electric machine stator structure is known from WO 2023232180 A1, comprising a stator core and a stator winding, the stator winding comprising a plurality of slots and conductor elements in the slots, the conductor elements having a plurality of bends which together form a wave-shaped course of the conductor elements, so that a coolant flowing through the slots can reach a cavity realized by the wave-shaped conductor elements. The conductor elements in the slots form an oil channel space. The stator winding is elastically fixed by the wave shape. Since the stator winding is fixed in the conductor slots by the wave shape, the conductor wires and the conductor slots should be designed to be fixed with interference. Higher assembly forces are generated during insertion, which can cause changes in the shape of the conductor wires and even damage to the insulation.

[0004] Conventional electric machines usually use a drop-in paint process to fill the in-slot space to fix the winding and transfer heat. However, if the gap between the stator winding and the conductor slots is too small, the in-slot oil cooling of the stator cannot be performed after the drop-in paint process, and the cooling effect is relatively low compared to in-slot oil cooling. The existing insulation materials and cooling schemes still have room for improvement in terms of structural complexity, cooling efficiency and installation convenience, for example, the winding of the WO 2023232180 A1 scheme does not effectively fix the conductor pieces. If the conductor pieces are not well fixed in the conductor slots, the conductor pieces are prone to vibration wear during operation, and the conductor insulation layer is at risk of wear and tear, thereby reducing the reliability and durability of the electric machine.

[0005] SUMMARY

[0006] The technical problem to be solved by the present invention is to provide an improved electric machine stator and electric machine, which can solve the problems of low cooling efficiency and unstable fixation of conductor pieces in the prior art.

[0007] The technical problem is solved by the motor stator designed according to the application. The motor stator comprises a stator core and a stator winding, the stator core has a plurality of radially extending conductor slots, and the stator winding has a plurality of conductor pieces, which are respectively inserted into the conductor slots in the axial direction and form a multi-layer structure in the radial direction. A spacer insulating piece is wound on the section of at least part of the conductor pieces contained in the conductor slots, and the spacer insulating piece in the conductor slots can form a cooling channel between the conductor pieces for guiding the cooling liquid to cool the conductor pieces. The conductor pieces in the conductor slots are laminated structures, and the conductor pieces are usually fixed by drop painting, so it is difficult to form a cooling channel for the cooling liquid to flow through between them. If the cooling channel is formed by the wave-shaped conductor pieces, the assembly force will be too high due to the interference fit. According to the design of the application, by winding the spacer insulating piece on at least part of the conductor pieces, a gap is formed between the laminated structures of the conductor pieces and / or between the conductor pieces and the conductor slots for forming the cooling channel for the cooling liquid to flow through, which improves the cooling efficiency. In addition, winding the spacer insulating piece on at least part of the conductor pieces also forms a pressing force on the surrounding conductor pieces, thereby improving the stability of the conductor pieces in the conductor slots, so that the stator winding is more stable. According to the type of motor stator and the structure of the winding, the spacer insulating piece can be wound on all or part of the conductor pieces according to actual needs, as long as the cooling channel is formed between the conductor pieces by the spacer insulating piece and the fixation of the conductor pieces in the conductor slots can be strengthened. This design enables the conductor pieces to be effectively cooled, and also prolongs the service life of the motor.

[0008] According to a preferred embodiment of the present application, the conductor member is an S-shaped winding, a U-shaped winding, an X-shaped winding or an I-shaped winding, and the spacer insulation member has a shape corresponding to the conductor member. The S-shaped winding (also commonly referred to as S-winding), the U-shaped winding (also commonly referred to as Hair-pin), the X-shaped winding (also commonly referred to as X-pin) or the I-shaped winding (also commonly referred to as I-pin) are common stator winding forms, and the spacer insulation member can be designed to closely fit the conductor member. Since the spacer insulation member can be made of a more flexible material and follow the corresponding shape of the conductor member, the spacer insulation member can absorb most of the compression force due to assembly, thus avoiding damage to the conductor member caused by large assembly force. Preferably, the spacer insulation member has a spiral shape. When spirally wound, the spacer insulation member generally does not overlap, and in this case, the space between the spacer insulation members forms a spiral hollow portion on the surface of the conductor member, which can form a cooling channel. The spiral design can increase the length of the cooling channel and improve the cooling efficiency. It is also preferred that the conductor member is designed as a flat wire. Generally, if a flat wire is used as a conductor member, a cooling channel cannot be provided due to the small gap between the conductor members. However, with the design of the present application, the spacer insulation member can be wound on the flat wire to form a cooling channel, and the flat wire design is advantageous for increasing the filling rate of the conductor member, thereby increasing the electrical conductivity of the stator.

[0009] According to a preferred embodiment of the present application, the spacer insulation member is a foamed insulation paper. The foamed insulation paper expands after the temperature rises, thereby fixing the conductor member and solving the problem of unstable fixation of the conductor member. During assembly, since a gap needs to be reserved for the subsequent expansion of the foamed insulation paper, the assembly force can be greatly reduced, and the assembly difficulty is reduced. Since the foamed insulation paper provides a large compression force due to expansion during use, it is considered a preferred solution that the conductor member forms a 2N-layer structure in each conductor slot, wherein the conductor member is wound in a spaced manner, i.e., only one layer of the two adjacent layers is provided with a spacer insulation member. Such a multi-layer structure design can reduce the stress between the conductor members while ensuring the cooling effect of the stator. It is also preferred that if the conductor member is a U-shaped winding, such as a hairpin winding, the spacer insulation member is wound on one leg of the conductor member, so that the same pretreatment can be performed on all winding conductor members, and the assembly complexity can be reduced. It is also considered that the spacer insulation member can be directly injection molded on the conductor member or attached to the conductor member, which saves the assembly steps and also improves the stability of the spacer insulation member on the conductor member.

[0010] According to a preferred embodiment of the present application, an insulation layer is arranged on the inner wall of the conductor slot. The arrangement of the insulation layer can prevent the conductor member from directly contacting the stator core, and further improve the insulation performance. It is further preferred that the insulation layer is formed by injection molding in the conductor slot. The injection-molded insulation layer can better fit on the conductor slot, and improve the insulation effect and production efficiency.

[0011] According to a preferred embodiment of the present application, the conductor slot has a slot opening, and the slot opening is sealed by a sealing member. The arrangement of the sealing member can prevent the cooling liquid from leaking, and ensure the effectiveness of the cooling channel.

[0012] The technical problem to be solved by the present application can also be solved by an electric machine. The electric machine comprises a stator, wherein the stator has the technical features described above. The electric machine has the characteristics of good cooling effect and stable conductor member fixation, and can significantly improve the performance and reliability of the electric machine. BRIEF DESCRIPTION OF DRAWINGS

[0013] The features, advantages, and technical effects of the exemplary embodiments of the present application will be described below with reference to the accompanying drawings. The accompanying drawings show:

[0014] Fig. 1 shows a partial perspective view of a stator of an electric machine;

[0015] Fig. 2 shows a partial enlarged view of a stator core;

[0016] Fig. 3 shows an embodiment of an insulation member;

[0017] Fig. 4 shows a perspective view of a stator winding designed according to the present application.

[0018] It should be noted that, in the description herein, unless otherwise explicitly specified and limited, the terms “axial”, “radial” and “circumferential” are all based on the central axis of the stator assembly. Specifically, the “axial” is the direction of extension of the central axis of the stator assembly or the direction extending parallel to the central axis; the “radial” is the direction perpendicular to the central axis of the stator assembly and intersecting the central axis; and the “circumferential” is the direction around the central axis of the stator assembly. DETAILED DESCRIPTION

[0019] Figure 1 shows a partial perspective view of a motor stator. For the sake of clarity, only half of the stator is shown in Figure 1. As shown, the motor stator is composed of a stator core 1 and a stator winding 2. A plurality of conductor slots 11 are evenly arranged in the circumferential direction of the stator core 1, and extend in the radial direction. An insulation layer 12 is arranged in the conductor slots 11. The insulation layer 12 can be formed on the inner wall of the conductor slots 11 by injection molding or by using slot paper. The insulation layer 12 can prevent the conductor pieces 21 from being damaged by contacting the stator core 1, and can provide additional insulation between the conductor pieces 21 and the stator core 1. The stator winding 2 is composed of conductor pieces 21. The conductor pieces 21 can be wave-shaped windings, U-shaped windings or I-shaped windings. The conductor pieces 21 of the stator winding 2 are inserted into the conductor slots 11 from the axial direction, and a plurality of groups of conductor pieces 21 are arranged in the radial direction in each conductor slot 11, thereby forming a multi-layer structure as shown in Figure 1, typically a 2N-layer structure. In the embodiment shown in Figure 1, a 6-layer structure is formed in each conductor slot 11. In the prior art, in order to fix the conductor pieces 21 in the conductor slots 11, the conductor pieces 21 are typically fixed by interference fit resulting from the wave shape of the conductor pieces 21 pressing against each other. Especially in the case of flat wire conductor pieces 21, the conductor pieces 21 are not completely fixed, and a large pressure is generated during assembly, which can cause changes in the shape of the conductor wire and even damage to the insulation.

[0020] Figure 2 shows a partial enlarged view of the stator core 1. In this embodiment, the conductor pieces 21 are, for example, U-shaped hairpin windings, and a 6-layer structure is formed in each conductor slot. A spacer insulation 22 is wound around the outer layer of the conductor pieces 21, and the spacer insulation 22 can form cooling channels for the flow of cooling liquid between the conductor pieces 21 and / or between the conductor pieces 21 and the conductor slots 11. The preferred material for the spacer insulation 22 is foamed insulation paper, which can expand when the temperature rises during operation of the stator, thereby firmly fixing the conductor pieces 21. As shown in the embodiment of Figure 2, not every conductor piece 21 is provided with a spacer insulation 22. In order to save costs and increase the space for oil channels, the spacer insulations 22 can be wound in a staggered arrangement in one conductor slot 11. For example, in the 6-layer structure shown in Figure 2, the first, third and fifth layers of hairpin conductor pieces 21 can be wound with foamed insulation paper (of course, the second, fourth and sixth layers can also be selected). The foamed insulation paper expands when heated, compressing the space in the conductor slot, so that all the conductor pieces 21 in the conductor slot can be better fixed, thereby solving the problem of vibration wear and durability risk.

[0021] Figure 3 shows an embodiment of the spacer insulation 22, which is designed in a spiral shape. The spacer insulation 22 is wound without overlapping in a spiral winding, forming a spiral hollow portion outside the conductor member 21, thus forming a cooling channel for the coolant. In this embodiment, the conductor member 21 is a U-shaped winding, for example a hairpin winding. The hairpin winding usually has two legs, and the spacer insulation 22 is wound only on one of the two leg portions of the hairpin winding, thus achieving the spacer winding of the conductor member 21 in a very simple manner. The spacer insulation 22 is preferably fixed to the conductor member 21 by means of adhesion or injection molding, facilitating transportation and assembly together with the conductor member 21.

[0022] The conductor slot 11 shown in Figure 2 has a slot opening 13 facing the radially inner side, and the insulation layer 12 is adhered to the peripheral wall of each conductor slot 11. The slot opening 13 is sealed by a sealing member 14 to prevent oil leakage. According to another embodiment, the conductor slot 11 can also be designed as a closed slot, thus eliminating the sealing member 14, but the closed slot can affect the electromagnetic performance of the conductor member 21.

[0023] Figure 4 shows a schematic perspective view of the stator winding designed according to the present application. The foamed insulation paper 22 designed according to the present application is spirally wound and adhered to one leg of the hairpin winding, thus being arranged in a staggered manner within one conductor slot 11, forming a spacer winding. During operation of the stator, the foamed insulation paper 22 expands due to heat, forming gaps between the conductor members 21 in the conductor slot 11, i.e. forming oil cooling channels. In addition, the effective fixation between the conductor members 21 is achieved by the thermal expansion of the foamed insulation paper 22, ensuring that the stator core is not affected by vibration wear and tear, thus improving the durability of the conductor.

[0024] It is apparent that the above-described embodiments of the present application are merely illustrative in nature and are not intended to limit the embodiments of the present application. Various changes or modifications can be made to the embodiments described above based on the teachings of the present application. It is not necessary to describe all such changes or modifications in this specification. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application should be included in the scope of the claims of the present application.

[0025] List of Reference Signs

[0026] 1 Stator core

[0027] 11 Conductor slot

[0028] 12 Insulation layer

[0029] 13 Slot opening

[0030] 14 Sealing member

[0031] 2 stator winding

[0032] 21 conductor member

[0033] 22 spacer insulation, foamed insulation paper

Claims

1. An electric machine stator comprising a stator core (1) and a stator winding (2), wherein the stator core (1) has a plurality of radially extending conductor slots (11), the stator winding (2) has a plurality of conductor pieces (21) which are respectively inserted axially into the conductor slots (11) and form a multi-layer structure in the radial direction, wherein a spacer insulation (22) is wound on a section of at least one of the conductor pieces (21) which is accommodated in the conductor slot (11), through which spacer insulation (22) cooling channels can be formed between the conductor pieces (21) and / or between the conductor pieces (21) and the conductor slot (11) for conducting a cooling liquid for cooling the conductor pieces (21).

2. The motor stator of claim 1, wherein, The conductor pieces (21) are S-shaped windings, U-shaped windings, X-shaped windings or I-shaped windings, and the spacer insulation (22) has a shape which is adapted to the conductor pieces (21).

3. The motor stator of claim 1, wherein, The spacer insulation (22) has a helical shape.

4. The motor stator of claim 2, wherein, The conductor pieces (21) are flat wires.

5. The motor stator of any one of claims 1 to 4, wherein, The spacer insulation (22) is foamed insulation paper.

6. The motor stator of claim 5, wherein, The conductor pieces (21) form a 2N-layer structure in each of the conductor slots (11), wherein the conductor pieces (21) are wound in a spaced manner.

7. The motor stator of claim 5, wherein, The conductor pieces (21) are U-shaped windings, and the spacer insulation (22) is wound on one of the legs of the conductor pieces (21).

8. The motor stator of any one of claims 1 to 4, wherein, The spacer insulation (22) is fixed to the conductor pieces (21) by means of an adhesive or injection molding.

9. The motor stator of any one of claims 1 to 4, wherein, An insulation layer (12) is provided in the conductor slots (11), wherein the insulation layer (12) is adhered to the inner wall of the conductor slots (11).

10. The motor stator of claim 9, wherein, The insulation layer (12) is injection molded in the conductor slots (11).

11. The motor stator of any one of claims 1 to 4, wherein, The conductor slots (11) have slot openings (13) which are sealed by a sealing element (14).

12. An electric machine characterized by The electric machine has an electric machine stator according to any one of claims 1 to 11.

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