Motor stator, manufacturing method thereof and motor

Abstract

The invention provides a motor stator, a manufacturing method thereof and a motor. The motor stator comprises an iron core and a winding which are assembled together. The winding includes a plurality of linear conductors having a cavity, and each linear conductor includes an insertion portion and an axial end portion. The axial end portions of the pair of linear conductors are connected together, and the axial end portions are provided with openings communicated with the cavity, so that each linear conductor forms a flow path from the opening of the axial end portion on one side of the axial direction to the opening of the axial end portion on the other side of the axial direction through the cavity, and therefore the cooling fluid can cool the winding through the flow path. Therefore, under the condition that the flow path for the cooling fluid to flow through is formed in the winding, the adverse effect of the winding on the insulation performance of the winding and the connectivity of the flow path due to conductor bending and flow path processing is reduced.

Description

Technical Field

[0001] The present application relates to the structure of an electric machine, and particularly to an electric machine stator, a manufacturing method thereof, and an electric machine including the electric machine stator. Background Art

[0002] Currently, electric machines are often used as power sources for outputting torque in pure electric vehicles or hybrid electric vehicles, and further an electric bridge drive system is constituted by using an electric machine and a transmission. With the development of the electric bridge drive system, higher performance is required, which requires effective cooling of the electric machine.

[0003] In an existing oil-cooled electric bridge drive system, a cooling fluid (such as oil) directly contacts a conductor for better heat transfer, for example, the axial end portions of the windings of the electric machine stator extending from the iron core are cooled by using a spraying method or a dripping method. However, after in-depth analysis of the thermal simulation results of the electric machine stator, it is found that if the portion of the winding located in the slots of the iron core can be directly cooled, rather than only the above-mentioned axial end portions of the winding, the performance of the electric machine can be significantly improved. Based on the above discovery, in a cooling structure of an electric machine stator having a waveform winding, a continuous hollow linear conductor is bent multiple times to form a waveform winding, and then openings are formed at the bent portions of the linear conductor, whereby the cavity inside the linear conductor and the formed openings are used to form a flow path for the cooling fluid to flow through. However, in such an electric machine stator having a waveform winding, each bending of the linear conductor will have an adverse effect on the insulation characteristics, and the cavity inside the linear conductor may be blocked, and the processing of forming openings after the linear conductor is bent will further have a more adverse effect on the insulation characteristics of the bent portions. Summary of the Invention

[0004] The present application is made in view of the state of the above-mentioned prior art. An object of the present application is to provide an electric machine stator and a manufacturing method thereof, by using which, when a flow path for a cooling fluid to flow through is formed inside the winding, the adverse effects on the insulation performance of the winding and the connectivity of the flow path caused by conductor bending and flow path processing can be reduced. Another object of the present application is to provide an electric machine including the above-mentioned electric machine stator.

[0005] In order to achieve the above object, the present application can adopt the following technical solutions.

[0006] The present application provides an electric machine stator as follows, including:

[0007] An iron core, which includes a plurality of slots spaced apart circumferentially in the electric machine stator; and

[0008] A winding, which is installed on the iron core and includes a plurality of linear conductors having cavities. Each of the linear conductors includes an insertion portion located in the slot and axial ends located on both axial sides of the insertion portion. The axial ends of paired linear conductors are connected together, and an opening communicating with the cavity is formed at each axial end, so that at least a part of the linear conductors form a flow path from the opening at the axial end on one axial side through the cavity to the opening at the axial end on the other axial side, whereby a cooling fluid can flow through the flow path to cool the winding.

[0009] In an alternative embodiment, the insertion portion of each linear conductor is located in only one of the slots, and the insertion portion extends linearly along the axis of the motor stator.

[0010] In another alternative embodiment, the axial end includes a twisted portion and a connecting portion. The two ends of the twisted portion are connected to the insertion portion and the connecting portion and are twisted relative to the insertion portion by a predetermined angle. The axial ends of paired linear conductors are connected to each other through the connecting portion.

[0011] In another alternative embodiment, the opening is formed on the axial end face of the connecting portion.

[0012] In another alternative embodiment, it further includes a conductive portion. Each conductive portion is located between the axial ends of paired linear conductors, so that the axial ends of paired linear conductors are connected together through the conductive portion.

[0013] In another alternative embodiment, the conductive portion contains a silver alloy, and the conductive portion is fixed to the axial end by sintering a nano silver alloy.

[0014] In another alternative embodiment, the side surface of the axial end is connected to the conductive portion.

[0015] The present application also provides a manufacturing method of the motor stator according to any one of the above technical solutions, characterized in that it includes:

[0016] An insertion step, in which a single wire that extends linearly and is pre-formed with the cavity and the opening is provided, and the single wire is inserted into the corresponding slot of the iron core of the motor stator, so that both ends of the single wire protrude from both axial sides of the iron core;

[0017] A twisting step, in which, in a state where the single wire is held in the slot, both ends of each single wire are twisted to form the linear conductor; and

[0018] A connecting step, in which axial ends of paired said linear conductors are connected together, whereby the multiple linear conductors form a predetermined electrical circuit.

[0019] The present application also provides a motor, characterized in that it includes the motor stator according to any one of the above technical solutions.

[0020] In an alternative solution, it further includes a housing and a connecting ring. The iron core of the motor stator is fixed to the housing and the connecting ring abuts or is mounted to the iron core. The housing, the connecting ring and the iron core enclose an annular flow path extending along the circumferential direction, and one of the axial ends of all the linear conductors is located in the annular flow path.

[0021] By adopting the above technical solutions, the present application provides a novel motor stator. In this motor stator, an iron core and a winding are assembled together. The iron core includes a plurality of slots spaced apart in the circumferential direction of the motor stator, and the winding is mounted on the iron core. Further, the winding includes multiple linear conductors having cavities, and each linear conductor includes an insertion portion and an axial end. The insertion portion is inserted into the slot of the iron core and is located in the slot, and the two axial ends are respectively located on the axial two sides of the insertion portion. Further, the axial ends of paired linear conductors are connected together, and an opening communicating with the cavity is formed at the axial end, so that each linear conductor forms a flow path from the opening at the axial end on one axial side through the cavity to the opening at the axial end on the other axial side, whereby the cooling fluid can cool the winding via the flow path. In this way, since the winding is formed by connecting mutually independent segmented linear conductors to form a predetermined structure and electrical circuit, not only can the number of bends of the conductor be greatly reduced, but also the cavity and the opening of the flow path can be pre-processed on the linear conductor. Thus, when a flow path for the cooling fluid to flow through is formed inside the winding, the adverse effects of conductor bending and flow path processing on the insulation performance and flow path connectivity of the winding are reduced. Further, the present application also provides a motor including the above motor stator, which has the same beneficial effects.

[0022] In addition, the present application also provides a manufacturing method of the above motor stator. The manufacturing method includes an insertion step, a twisting step and a connecting step. In the insertion step, a single wire extending linearly and pre-formed with a cavity and an opening is provided, and the single wire is inserted into the corresponding slot of the stator iron core, so that both ends of the single wire protrude from the axial two sides of the iron core of the stator. In the twisting step, while the single wire is held in the slot, both ends of each single wire are twisted to form a linear conductor. In the connecting step, axial ends of paired linear conductors are connected together, whereby multiple linear conductors form a predetermined electrical circuit. Thus, the large-scale industrial production of the motor stator of the present application can be realized by a relatively simple manufacturing method. Description of the Drawings

[0023] Figure 1A is a front view schematic diagram showing a motor stator according to an embodiment of the present application.

[0024] Figure 1B shows Figure 1A a side view schematic diagram of the motor stator in

[0025] Figure 1C shows Figure 1A an enlarged schematic diagram of a partial structure of the motor stator in

[0026] Figure 1D shows Figure 1A another enlarged schematic diagram of a partial structure of the motor stator in

[0027] Figures 2A to 2C is for explaining Figure 1A an illustrative schematic diagram of a manufacturing method of the motor stator in

[0028] Figure 3 is a cross-sectional schematic diagram showing a bridge drive system including a motor according to the present application, in which the cross-hatching is omitted.

[0029] Description of Reference Numerals

[0030] 1 Stator; 11 Iron Core; 12 Winding; 121 Linear Conductor; 121p Opening; 1211 Insertion Portion; 1212 Axial End; 1212t Torsion Portion; 1212e Connection Portion; 122 Conductive Portion

[0031] 2 Housing; 21 Cylindrical Main Body; 22 Side Wall

[0032] 3 Connection Ring

[0033] 4 Rotor

[0034] S Annular Flow Path; W1 First Intermediate; W2 Second Intermediate; A Axial; R Radial; C Circumferential Detailed Embodiments

[0035] The following describes exemplary embodiments of the present application with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not used to exhaust all feasible ways of the present application, nor to limit the scope of the present application.

[0036] In the present application, unless otherwise specifically stated, "axial", "radial" and "circumferential" respectively refer to the axial, radial and circumferential directions of the motor stator (iron core). "Axial side" refers to, for example, Figure 3 the right side in Figure 3On the left side; "radially outer" refers to the side along the radial direction away from the central axis of the motor, and "radially inner" refers to the side along the radial direction approaching the central axis of the motor.

[0037] The motor stator according to an embodiment of the present application will be described below with reference to the accompanying drawings of the specification.

[0038] In this embodiment, as Figures 1A to 1D shown, the motor stator 1 according to an embodiment of the present application includes an iron core 11 and a winding 12 assembled together. The iron core 11 has an overall cylindrical structure, and the iron core 11 can be formed by laminating and fixing a plurality of silicon steel sheets in the axial direction A. Further, the iron core 11 includes a yoke portion and a plurality of tooth portions. The yoke portion extends continuously in the circumferential direction C over the entire circumference. The plurality of tooth portions project from the yoke portion toward the radially inner side, and the plurality of tooth portions are arranged at intervals in the circumferential direction C, so that a plurality of slots uniformly distributed at intervals in the circumferential direction C are defined by the plurality of tooth portions. Axial ends of these slots are open toward the outside, the radially outer ends of the slots are closed, and the radially inner ends are open.

[0039] In this embodiment, as Figure 1A and Figure 1D shown, the winding 12 includes a plurality of independent linear conductors 121 and a conductive portion 122. The linear conductors 121 are connected together through the conductive portion 122 to form a predetermined structure and an electrical circuit. The linear conductor 121 can be a flat copper single wire with a rectangular cross-section, and the flat copper single wire can be formed by a strip conductor coated with an insulating layer. Specifically, the linear conductor 121 includes an insertion portion 1211 and two axial end portions 1212 (see Figure 2C ). The insertion portion 1211 of each linear conductor 121 is inserted into and located in one slot of the iron core 11, and the insertion portion 1211 extends linearly along the axial direction A. The two axial end portions 1212 are not only located on the axial sides of the insertion portion 1211, but also project from the iron core 11 toward the axial sides. Each axial end portion 1212 includes a torsion portion 1212t and a connection portion 1212e. Both ends of the torsion portion 1212t are connected to the insertion portion 1211 and the connection portion 1212e and are twisted relative to the insertion portion 1211 at a predetermined angle. The axial end portions 1212 of the paired linear conductors 121 are connected to each other through the connection portion 1212e, and electrical connection is achieved via the conductive portion 122.

[0040] In order to form a flow path inside the winding 12 for the cooling fluid to flow through, the linear conductor 121 is formed into a hollow structure, thereby forming a cavity that extends from the axial end 1212 on one axial side along the extending direction of the linear conductor 121 to the axial end 1212 on the other axial side. In addition, openings 121p communicating with the cavity are formed at both axial ends 1212 of the linear conductor 121, whereby each linear conductor 121 forms a flow path from the opening 121p at one axial end 1212 through the cavity to the opening 121p at the other axial end. In this embodiment, the side surfaces of the connection portions 1212e of the axial ends 1212 of the paired linear conductors 121 are connected to each other via the conductive portion 122 to achieve electrical connection. Therefore, in order to prevent the openings 121p of the connection portions 1212e from being blocked, the openings 121p are formed on the axial end faces of the connection portions 1212e. That is, the openings 121p in this embodiment are formed on the axial end faces of the connection portions 1212e, rather than on the side surfaces or side walls (or circumferential surfaces / walls) of the axial ends 1212. Compared with drilling holes in the side surfaces or side walls of the axial ends 1212 to form openings, the winding of the present application can avoid the insulation risks brought about by drilling.

[0041] In this embodiment, each conductive portion 122 is located between the axial ends 1212 of the paired linear conductors 121, such that the axial ends 1212 of the paired linear conductors 121 are mechanically and electrically connected through the conductive portion 122. The conductive portion 122 contains a silver alloy, and the axial ends 1212 of the linear conductor 121 can be electrically connected by using the low-temperature sintering nano-silver alloy technology. For example, after the conductive portion 122 is arranged between the axial ends 1212 of the paired linear conductors 121, the entire motor stator 1 can be placed in a heating appliance and heated at a temperature of, for example, 150 degrees (maximum 180 degrees) for 20 to 30 minutes, thereby causing the atoms of the silver alloy material to diffuse into the linear conductor 121 to form a dense crystal, whereby the paired linear conductors 121 are configured into a firm whole through the conductive portion 122 and electrical connection is achieved. It can be understood that since the temperature required for sintering the nano-silver alloy is relatively low, the heat generated during the processing can be significantly reduced. After the heat is reduced, the adverse effects on the structure of the hollow linear conductor 121 are significantly reduced, such that after the entire winding 12 is formed, the cooling fluid can flow smoothly along the flow path of the winding 12. Moreover, the melting point of the conductive portion 122 after sintering will increase significantly, thereby not only meeting the requirements for electrical conductivity and structural strength, but also meeting the other operating conditions requirements of the motor stator 1.

[0042] The manufacturing method of the above-mentioned motor stator 1 will be described below.

[0043] The manufacturing method of the motor stator 1 according to an embodiment of the present application includes an insertion step, a twisting step, and a connection step that are sequentially performed. In the insertion step, as Figure 2A shown, a single wire that linearly extends and is preformed with a cavity and an opening 121p can be provided as the first intermediate W1. The insulating layers of the two end portions of the single wire are removed by a predetermined length to form a second intermediate W2 as Figure 2B shown. After the iron core 11 is installed in place, multiple single wires are inserted into the corresponding slots of the iron core 11 of the electronic stator 1 such that the two end portions of the single wire protrude from the two axial sides of the iron core 11 of the motor stator 1. Further, in the twisting step, after all the single wires are installed in place, a dedicated tool can be used to perform a twisting operation on the single wires. Specifically, while the single wires are held in the slots, the two end portions of each single wire are twisted by a predetermined angle using the above-mentioned tool, thereby forming a linear conductor 121 as Figure 2C shown. Further, in the connection step, a conductive portion 122 is arranged between the axial end portions 1212 of the paired linear conductors 121, and the axial end portions 1212 of the paired linear conductors 121 can be connected together by a welding method such as nano-silver welding, whereby multiple linear conductors 121 form a predetermined electrical circuit. In this way, the twisted linear conductors 121 are used to form a motor stator as Figures 1A to 1D shown.

[0044] It can be understood that the statement in the present application that the conductive portion 122 is arranged between the axial end portions 1212 of the paired linear conductors 121, the conductive portion 122 is located between the axial end portions 1212 of the paired linear conductors 121, etc. only means that there may be a conductive portion 122 between the axial end portions 1212 of the paired linear conductors 121, and does not mean that the conductive portion 122 only exists between the axial end portions 1212 of the paired linear conductors 121.

[0045] The following describes a motor including the above-mentioned motor stator 1 and a bridge drive system including the motor.

[0046] As Figure 3As shown, a motor according to an embodiment of the present application includes a motor stator 1, a housing 2, a connecting ring 3, and a motor rotor 4 assembled together. The motor stator 1, the motor rotor 4, and the connecting ring 3 are disposed inside the housing 2. The motor stator 1 may have the structure described in the above embodiments. The housing 2 includes a cylindrical main body 21 and a side wall 22 formed integrally, and the side wall 22 extends radially inward from the cylindrical main body 21. The iron core 11 of the motor stator 1 is located radially inside the cylindrical main body 21 and fixed to the cylindrical main body 21, whereby the motor stator 1 and the housing 2 are fixed relative to each other. The connecting ring 3 is formed in a circular ring shape, one end of the connecting ring 3 abuts or is mounted to the iron core 11 of the motor stator 1, and the other end is fixed to the side wall 22 of the housing 2. Thus, the iron core 11 of the motor stator 1, the housing 2, and the connecting ring 3 surround and form an annular flow path S extending in the circumferential direction, and one axial end 1212 (the axial end 1212 located on one axial side) of all the linear conductors 121 is located in the annular flow path S. In addition, no similar annular flow path S is formed on the other axial side of the motor, so the other axial end 1212 (the axial end 1212 located on the other axial side) of all the linear conductors 121 is not immersed in the cooling flow path. In addition, the motor rotor 4 is located radially inside the motor stator 1 and has an air gap with the motor stator 1.

[0047] Further, as Figure 3 shown, the bridge drive system includes the above-mentioned motor and a transmission. The housing 2 of the motor and the housing of the transmission can be mounted together, and the rotor shaft of the motor rotor 4 extends to the position where the transmission is located and is in transmission connection with the gear transmission mechanism inside the transmission. The cooling fluid (such as oil) from the transmission can be pumped into the annular flow path S through a pumping device, so that the axial ends 1212 located on one axial side of all the linear conductors 121 of the winding 12 are immersed in the cooling fluid, and then the cooling fluid can flow along the flow path in each linear conductor 121 to the other axial side of the linear conductor 121. In this process, the cooling fluid can effectively cool the winding 12, especially the part of the winding 12 located inside the iron core 2. Therefore, the motor according to the present application is a so-called oil-cooled motor, and the bridge drive system according to the present application is an oil-cooled bridge drive system.

[0048] By adopting the above technical solution, in the motor stator 1 according to the present application and the motor including the motor stator 1, since the winding 12 is formed by connecting mutually independent segmented linear conductors 121 to form a predetermined structure and electrical circuit, not only can the excessive bending times like a long conductor be avoided, but also the cavities and openings 121p of the flow path can be pre-processed on the linear conductor 121 without drilling openings after bending. Thus, when a flow path for the cooling fluid to flow through is formed inside the winding 12, the adverse effects of conductor bending and flow path processing on the insulation performance and flow path connectivity of the winding 12 are reduced.

[0049] Even compared with the hairpin winding, the winding of the present application has obvious advantages. The bending angle of the linear conductor 121 of the present application is small, and the influence of bending on the insulating layer is small. Without forming openings by drilling on the side or side wall of the conductor, the winding of the present application can avoid the insulation risk brought by drilling.

[0050] It should be understood that the above embodiments are merely exemplary and do not limit the present application. Those skilled in the art can make various modifications and changes to the above embodiments under the teaching of the present application without departing from the scope of the present application. The following is a supplementary description of the technical solution of the present application.

[0051] i. It can be understood that the motor according to the present application can be applied not only to the above-mentioned bridge drive system, but also to other vehicle power systems, such as a hybrid system.

[0052] ii. In the above embodiments, the opening 121p is formed on the end face of the connection portion 1212e of the axial end 1212 of the linear conductor 121, but the present application is not limited thereto. For example, in an alternative solution, without affecting the linear conductor 121 from realizing a predetermined electrical circuit, the opening 121p can be formed on the axial end 1212, that is, the side face of the connection portion 1212e or the torsion portion 1212t that is not used for connecting to the conductive portion 122, and multiple openings 121p can be formed on each connection portion 1212e.

[0053] iii. In the technical solution of the present application, since the cooling fluid continuously flows along the flow path inside the winding 12, the cooling fluid can cool the hottest part of the motor stator 1 (the part of the winding 12 located inside the iron core 1). This can greatly improve the heat dissipation capacity of the motor stator 1, thereby improving the heat dissipation efficiency and the performance of the motor including the motor stator 1.

Claims

1. A motor stator, characterized in that, Comprising: A core (11), which includes a plurality of slots spaced apart circumferentially (C) of the motor stator (1); And A winding (12), which is mounted on the core (11) and includes a plurality of linear conductors (121) having cavities. Each of the linear conductors (121) includes an insertion portion (1211) located in the slot and axial ends (1212) located on both axial sides of the insertion portion (1211). The axial ends (1212) of paired linear conductors (121) are connected together, and an opening (121p) communicating with the cavity is formed at each of the axial ends (1212), such that at least a part of the linear conductors (121) forms a flow path from the opening (121p) of the axial end (1212) on one axial side through the cavity to the opening (121p) of the axial end on the other axial side, whereby a cooling fluid can flow through the flow path to cool the winding (12).

2. The motor stator according to claim 1, characterized in that, The insertion portion (1211) of each of the linear conductors (121) is located in only one of the slots, and the insertion portion (1211) extends linearly along the axial direction (A) of the motor stator (1).

3. The stator of an electric machine according to claim 2, characterized in that, The axial end (1212) includes a torsion portion (1212t) and a connection portion (1212e). Both ends of the torsion portion (1212t) are connected to the insertion portion (1211) and the connection portion (1212e) and are twisted relative to the insertion portion (1211) by a predetermined angle. The axial ends (1212) of paired linear conductors (121) are connected to each other through the connection portion (1212e).

4. The motor stator according to claim 3, characterized in that, The opening (121p) is formed on the axial end face of the connection portion (1212e).

5. The motor stator according to any one of claims 1 to 4, characterized in that, It further includes a conductive portion (122). Each of the conductive portions (122) is located between the axial ends (1212) of paired linear conductors (121), such that the axial ends (1212) of paired linear conductors (121) are connected together through the conductive portion (122).

6. The stator of an electric machine according to claim 5, characterized in that, The conductive portion (122) contains a silver alloy, and the conductive portion (122) is fixed to the axial end (1212) by sintering a nano silver alloy.

7. The motor stator according to claim 5, characterized in that, The side surface of the axial end (1212) is connected to the conductive portion (122).

8. A manufacturing method of the motor stator according to any one of claims 1 to 7, characterized in that, Comprising: An insertion step, in which a single wire that extends linearly and pre - forms the cavity and the opening (121p) is provided, and the single wire is inserted into the corresponding slot of the core (11) of the motor stator (1), such that both ends of the single wire protrude from both axial sides of the core (11); A torsion step, in which, in a state where the single wire is held in the slot, both ends of each single wire are twisted, thereby forming the linear conductor (121); and A connection step, in which the axial ends (1212) of paired linear conductors (121) are connected together, whereby the plurality of linear conductors (121) form a predetermined electrical circuit.

9. A motor, characterized in that, Including the motor stator (1) according to any one of claims 1 to 7.

10. The motor according to claim 9, characterized in that, It further includes a housing (2) and a connecting ring (3). The iron core (11) of the motor stator (1) is fixed to the housing (2), and the connecting ring (3) abuts against or is mounted to the iron core (11). The housing (2), the connecting ring (3) and the iron core (11) enclose an annular flow path (S) extending along the circumferential direction (C), and one axial end (1212) of all the linear conductors (121) is located in the annular flow path (S).

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