Electric motor and vehicle powertrain

Abstract

This application provides an electric motor and a power system for vehicles. The motor incorporates a cooling structure in which an annular flow path is formed on one axial side of the iron core using an iron core, a winding bobbin, and a connecting ring. An axial flow path is also formed between adjacent windings in each winding slot of the iron core using the iron core and the winding bobbin, with each axial flow path communicating with the annular flow path. Cooling fluid (e.g., cooling oil) guided into the annular flow path effectively cools the portion of the winding located within it, and cooling fluid entering the axial flow path from the annular flow path effectively cools the portion of the winding located within the axial flow path. This effective cooling of the motor (especially the windings) improves the motor's continuous output power and extends its service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric machines, and in particular to an electric machine with a cooling structure and a vehicle power system comprising the same. BACKGROUND

[0002] Electric machines are used to output torque and power, and the cooling of the electric machine is very important for the electric machine to output specified torque and power. The cooling capacity of the cooling structure of the electric machine is a decisive factor affecting the sustained output power of the electric machine. In the prior art, the structure of most cooling systems is designed to have a nozzle to directly spray cooling fluid (such as cooling oil) onto the stator to take away heat. SUMMARY

[0003] The inventor found that the hottest part on the stator is located on the winding, and the cooling fluid in the cooling structure of the existing electric machine cannot directly flow through the surface of the winding, which results in that the cooling fluid cannot take away enough heat from the stator in time. Therefore, the temperature of the stator of the existing electric machine is very high during operation, which makes the insulation performance of the electric machine at risk of failure, and reduces the service life of the electric machine.

[0004] The present application is made in view of the above state of the art. One object of the present application is to provide an electric machine, the cooling structure of which can effectively cool the stator of the electric machine and reduce the adverse effects caused by the excessively high temperature of the stator during operation of the electric machine. Another object of the present application is to provide a vehicle power system comprising the above electric machine.

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

[0006] The present application provides an electric machine comprising:

[0007] a core having a plurality of winding teeth distributed at intervals in the circumferential direction of the electric machine, a winding slot being defined between every two adjacent winding teeth;

[0008] a winding, one winding being wound on each winding tooth, two adjacent windings being spaced apart in the same winding slot;

[0009] a winding drum attached to the core, the winding drum closing the radial opening of each winding slot, so that an axial flow path extending in the axial direction of the electric machine is defined between two adjacent windings in each winding slot; and

[0010] A connecting ring, which is fixed relative to the iron core and located on one side of the iron core, the connecting ring, the iron core and the winding bobbin surround and form an annular flow path extending along the circumference of the entire circumference, the axial end of all the windings is located in the annular flow path, and the annular flow path is in communication with the axial flow path.

[0011] In one alternative embodiment, the connecting ring has a sidewall and a bottom wall, the bottom wall extending from the sidewall toward the winding drum and abutting against the winding drum, the bottom wall defining the annular flow path from the radially inward side.

[0012] In another alternative embodiment, the connecting ring further has a top wall located radially outward of the bottom wall, the top wall extending from the side wall toward the core, the top wall abutting against the core, and the top wall defining the annular flow path radially outward.

[0013] In another alternative embodiment, the core includes a core body and a core support frame. The core body is formed by stacking metal sheets, and the core support frame is used to hold and support the core body. The top wall abuts against the core support frame.

[0014] In another alternative, the top wall is formed with a through first hole through which cooling fluid can enter the annular flow path.

[0015] In another alternative embodiment, the motor further includes a housing, wherein the iron core, the winding, the winding bobbin, and the connecting ring are all located inside the housing and fixed relative to the housing.

[0016] In another alternative embodiment, the housing comprises a cylindrical housing body located radially outside the iron core and the connecting ring, the housing body being fixedly mounted together with the iron core and the connecting ring.

[0017] In another alternative embodiment, at a location opposite to the first through hole of the connecting ring, the housing body forms a through second through hole, through which cooling fluid can enter the annular flow path.

[0018] In another alternative, both the winding spool and the connecting ring are made of insulating material.

[0019] This application also provides a vehicle power system including the electric motor described in any of the above technical solutions.

[0020] By adopting the above technical solution, this application provides a novel electric motor. In this motor, a cooling structure is formed in which an annular flow path is formed on one axial side of the iron core using an iron core, a winding bobbin, and a connecting ring; an axial flow path is formed between adjacent windings in each winding slot of the iron core using the iron core and the winding bobbin, and each axial flow path is connected to the annular flow path. Cooling fluid (e.g., cooling oil) guided into the annular flow path can effectively cool the portion of the winding located in the annular flow path, and cooling fluid entering the axial flow path from the annular flow path can effectively cool the portion of the winding located in the axial flow path. Furthermore, the cooling fluid flowing through the annular flow path and the axial flow path can cool the iron core.

[0021] Thus, in the technical solution of this application, a relatively simple cooling structure for the motor is formed, thereby effectively cooling the motor stator and reducing the adverse effects that may occur due to excessive temperature during motor operation, such as reducing the risk of insulation failure caused by excessive temperature. Furthermore, effective motor cooling can improve the motor's continuous output power and extend its service life. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing a partial structure of a motor according to an embodiment of the present application, wherein the partial structure including an annular flow path is shown in cross-section.

[0023] Figure 2 It shows Figure 1 A schematic diagram of a partial structure of the motor is shown, which illustrates the partial structure including the axial flow path.

[0024] Figure 3 It shows Figure 1 A schematic diagram of a partial structure of the motor is shown, which illustrates a partial structure including a first through hole and a second through hole.

[0025] Explanation of reference numerals in the attached figures

[0026] 1. Iron core; 11. Iron core body; 11t winding teeth; 11c winding groove; 12. Iron core support frame;

[0027] 2 windings;

[0028] 3. Winding spool;

[0029] 4. Connecting ring; 41. Side wall; 42. Bottom wall; 43. Top wall; 4h. First through hole;

[0030] 5. Shell body; 5h. Second through hole;

[0031] P1 is an annular flow path; P2 is an axial flow path;

[0032] A represents the axial direction; R represents the radial direction; C represents the circumferential direction. Detailed Implementation

[0033] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0034] In this application, unless otherwise specified, "axial," "radial," and "circumferential" refer to the axial, radial, and circumferential directions of the motor, respectively. "One side of the axial direction" refers to... Figure 1 The right side of the axis, "the other side of the axis" refers to Figure 1 On the left side, "radial outer side" refers to the side that is radially away from the central axis of the motor, while "radial inner side" refers to the side that is radially closer to the central axis of the motor.

[0035] According to one embodiment of this application, the motor is a centrally wound motor, which mainly includes a housing, a stator, a rotor, and a shaft. The stator, rotor, and shaft are coaxially arranged and substantially located within the space enclosed by the housing. The stator is fixed to the housing and includes an iron core and windings. The rotor is located radially inside the stator and is rotatable relative to the stator, and there is an air gap between the rotor and the stator. The shaft and rotor can be fixed together, and the shaft is located radially inside the rotor.

[0036] Furthermore, the motor according to one embodiment of this application is provided with a cooling structure for cooling the stator. In this cooling structure, cooling oil is used as the cooling fluid to cool the stator core and coils (especially the hottest part of the coils). Therefore, the motor according to one embodiment of this application is an oil-cooled motor.

[0037] The specific structure of an electric motor according to an embodiment of this application will be described below with reference to the accompanying drawings, and in particular, the cooling structure for cooling the stator will be described.

[0038] like Figures 1 to 3 As shown, an electric motor according to an embodiment of this application includes an iron core 1, a winding 2, a winding bobbin 3, a connecting ring 4, and a housing assembled together, with other components fixed together with the housing, wherein the iron core 1, the winding 2, and the winding bobbin 3 are used to form a stator.

[0039] In this embodiment, as Figures 1 to 3As shown, the core 1 includes a core body 11 and a core support frame 12. The core body 11 can be constructed by stacking multiple silicon steel sheets together in the axial direction A, and the core body 11 has an overall cylindrical structure. The core body 11 has an annular body and multiple winding teeth 11t protruding radially inward from the annular body, the multiple winding teeth 11t being spaced apart in the circumferential direction C. A winding groove 11c is defined between every two adjacent winding teeth 11t in the circumferential direction C, each winding groove 11c penetrating the core 1 along the axial direction A and each winding groove 11c having a radial opening that opens radially inward. The core support frame 12 is used to hold and support the core body 11 to help maintain the shape and structure of the core body 11. The core support frame 12 has an annular portion located on one axial side of the annular body of the core 1, the annular portion being mounted and abutting against the annular body of the core body 11.

[0040] In this embodiment, as Figures 1 to 3 As shown, a winding 2 is wound on each winding tooth 11t. During the winding process, these windings 2 pass through the winding slots 11c adjacent to the winding tooth 11t. Two adjacent windings 2 are spaced apart within the same winding slot 11c. Here, "spaced apart" means there is a gap between the two adjacent windings; this does not preclude the possibility that the two adjacent windings 2 may contact each other at local locations, as long as... Figure 2 As shown, there should be a gap between two adjacent windings 2 in the same winding slot 11c that runs through the axial direction A.

[0041] In this embodiment, the winding bobbin 3 (also referred to as the winding frame) is made of insulating material. The winding bobbin 3 can be attached to the iron core 1 using a secondary molding process, or it can be manufactured separately and fixedly attached to the iron core 1 by other mechanical means. The winding bobbin 3 is attached to the winding teeth 11t, serving two purposes: firstly, to support the winding 2 wound on the winding teeth 11t; and secondly, to provide secondary insulation between the winding 2 and the iron core 1. Further, in this embodiment, as... Figure 1 and Figure 2 As shown, the winding drum 3 closes the radial opening of each winding slot 11c, so that the winding drum 3, together with the iron core 1 and the winding 2, defines an axial flow path P2 extending along the axial direction A between two adjacent windings 2 in each winding slot 11c.

[0042] In this embodiment, the connecting ring 4 (also referred to as the insulating ring) is made of insulating material. The connecting ring 4 can be formed independently using methods such as injection molding. Figures 1 to 3As shown, since both the connecting ring 4 and the iron core 1 are fixed to the housing, the connecting ring 4 and the iron core 1 are relatively fixed. The connecting ring 4 is located on one axial side of the iron core 1. The connecting ring 4, the iron core 1, and the winding bobbin 3 surround and form an annular flow path P1 extending along the circumferential direction C. One axial end of all the windings 2 is located in the annular flow path P1, which communicates with the axial flow path P2. Specifically, the connecting ring 4 extends continuously along the circumferential direction C. The connecting ring 4 has a side wall 41, a bottom wall 42, and a top wall 43 formed integrally. The side wall 41 has a certain radial width and an axial width. The bottom wall 42 extends a certain width from the radially inner end of the side wall 41 toward the other axial side (that is, toward the winding bobbin 3) and abuts tightly against the winding bobbin 3, thereby defining the annular flow path P1 from the radially inner side.

[0043] It is understandable that a sealing ring can be provided between the bottom wall 42 and the winding drum 3. Of course, it is also possible for the bottom wall 42 and the winding drum 3 to not be tightly abutting each other or to form holes or grooves, so that the cooling fluid flowing out from the annular flow path P1 can cool the rotor.

[0044] The top wall 43 extends a certain width from the radially outer end of the side wall 41 toward the other side axially (i.e., toward the winding drum 3) and closely abuts against the core support frame 12, thereby defining an annular flow path P1 from the radially outer side. Further, as... Figure 3 As shown, the top wall 43 has a first through hole 4h extending radially R, through which cooling fluid can enter the annular flow path P1.

[0045] The iron core 1, winding 2, winding bobbin 3, and connecting ring 4 are all located inside the housing and fixed relative to the housing. In this embodiment, as... Figures 1 to 3 As shown, the housing includes a cylindrical housing body 5, which is located radially outside the iron core 1 and the connecting ring 4. The housing body 5 is fixedly installed with the iron core 1 and the connecting ring 4, for example, by an interference fit. At the location opposite to the first through hole 4h of the connecting ring 4, the housing body 5 has a second through hole 5h extending radially R, through which cooling fluid can enter the annular flow path P1.

[0046] By adopting the above structural scheme, the axial flow path P2 formed in each winding slot 11c is connected to the annular flow path P1, and the second through hole 5h is connected to the annular flow path P1 via the first through hole 4h. Thus, according to an embodiment of the present application, the motor utilizes the annular flow path P1, the axial flow path P2, the first through hole 4h, and the second through hole 5h to form a cooling structure through which cooling fluid flows to cool the stator. The cooling fluid flows sequentially through the second through hole 5h, the first through hole 4h, the annular flow path P1, and the axial flow path P2 in the cooling structure.

[0047] Since the axial end of winding 2 is always located in the annular flow path P1, the cooling fluid entering the annular flow path P1 through the two through holes 4h and 5h can effectively reduce the temperature of the axial end of winding 2. The cooling fluid flowing from the annular flow path P1 through the axial flow path P2 can further reduce the temperature of the portion of winding 2 located in the winding slot 11c. The cooling fluid flowing out of the axial flow path P2 can cool the temperature of the other axial end of winding 2. Moreover, during the flow of cooling fluid through the annular flow path P1 and the axial flow path P2, in addition to cooling winding 2, the core 1 can also be cooled. In summary, the cooling fluid flowing in the above structure can effectively cool the stator of the motor. As a result, the adverse effects caused by excessive stator temperature during motor operation can be reduced; and under the same test conditions, compared with existing motors, the continuous output power of the motor of this application with the above cooling structure can be increased by 60% to 75%.

[0048] It should be understood that the above embodiments are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above embodiments under the teachings of this application without departing from the scope of this application. The technical solutions of this application are further described below.

[0049] i. This application also provides a vehicle powertrain system, which includes the electric motor of this application. This vehicle powertrain system can be an electric axle drive system, which may further include a transmission mechanism such as a gearbox. The motor is drive-connected to the input shaft of the gearbox to achieve bidirectional torque transmission. This electric axle drive system can be used as a drive system for a pure electric vehicle, or it can be used in conjunction with an engine to form a hybrid powertrain system for a hybrid vehicle.

[0050] ii. In the technical solution of the motor in this application, an oil supply system communicating with the second through hole 5h can be provided outside the motor housing. The oil supply system may include a pump and an oil circuit (oil pipe), so that cooling oil as a cooling fluid can be supplied to the cooling structure by means of the oil supply system.

[0051] Furthermore, when installing the motor of this application, the first through hole 4h and the second through hole 5h should be positioned at the top, so that the cooling fluid entering the annular flow path P1 through the first through hole 4h and the second through hole 5h can flow through the entire annular flow path P1 under the action of gravity. It is understood that, in order for the cooling fluid to flow smoothly through the entire annular flow path P1, the bottom wall 42 of the connecting ring 4 is in as close contact as possible with the winding drum 3, or even connected to it, and the top wall 43 of the connecting ring 4 is in as close contact as possible with the iron core support frame 12, or even connected to it, so that the annular flow path P1 achieves a sealed structure except for communication with the first through hole 4h and the axial flow path P2.

[0052] iii. It is understood that, in the alternative scheme, the core support frame 12 can be integrated with the winding drum 3, that is, a part of the structure of the winding drum 3 can play the role of supporting the core body 11.

[0053] iv. The above embodiments illustrate that the top wall 43 has a first through hole 4h extending radially R, through which cooling fluid can enter the annular flow path P1; however, this application is not limited thereto. In an alternative embodiment, a through hole communicating with the annular flow path can be formed on the radially outer portion of the side wall 41 of the connecting ring 4, through which the function of inputting cooling fluid into the annular flow path can also be achieved.

Claims

1. An electric motor, characterized in that, include: The core (1) has a plurality of winding teeth (11t) spaced apart on the circumferential (C) side of the motor, and a winding groove (11c) is defined between every two adjacent winding teeth (11t). A winding (2) is wound on each of the winding teeth (11t), and two adjacent windings (2) are spaced apart in the same winding slot (11c); A winding bobbin (3), attached to the winding teeth (11t) of the iron core (1), serves two purposes: firstly, to support the windings (2) wound on the winding teeth (11t); and secondly, to provide secondary insulation between the windings (2) and the iron core (1). The bobbin (3) closes the radial opening of each winding slot (11c), thereby defining an axial flow path (P2) extending along the axis (A) of the motor between two adjacent windings (2) in each winding slot (11c). A connecting ring (4) is fixed relative to the iron core (1) and located on one side of the iron core (1). The connecting ring (4), the iron core (1) and the winding bobbin (3) surround and form an annular flow path (P1) extending along the circumference (C) on the whole circumference. The axial end of all the windings (2) is located in the annular flow path (P1), which is connected to the axial flow path (P2).

2. The motor according to claim 1, characterized in that, The connecting ring (4) has a side wall (41) and a bottom wall (42), the bottom wall (42) extending from the side wall (41) toward the winding bobbin (3), the bottom wall (42) abutting against the winding bobbin (3), and the bottom wall (42) defining the annular flow path (P1) from the radially inner side.

3. The motor according to claim 2, characterized in that, The connecting ring (4) also has a top wall (43) located radially outside the bottom wall (42), the top wall (43) extending from the side wall (41) toward the iron core (1), the top wall (43) abutting against the iron core (1), and the top wall (43) defining the annular flow path (P1) radially outside.

4. The motor according to claim 3, characterized in that, The iron core (1) includes an iron core body (11) and an iron core support frame (12). The iron core body (11) is formed by stacking metal sheets. The iron core support frame (12) is used to hold and support the iron core body (11). The top wall (43) abuts against the iron core support frame (12).

5. The motor according to claim 3, characterized in that, The top wall (43) has a through first hole (4h) through which cooling fluid can enter the annular flow path (P1).

6. The motor according to any one of claims 1 to 5, characterized in that, The motor also includes a housing, and the iron core (1), the winding (2), the winding spool (3) and the connecting ring (4) are all located inside the housing and fixed relative to the housing.

7. The motor according to claim 6, characterized in that, The housing includes a cylindrical housing body (5), which is located radially outside the iron core (1) and the connecting ring (4). The housing body (5) is fixedly installed together with the iron core (1) and the connecting ring (4).

8. The motor according to claim 7, characterized in that, At the location opposite to the first through hole (4h) of the connecting ring (4), the housing body (5) is formed with a through second through hole (5h), through which cooling fluid can enter the annular flow path (P1) via the second through hole (5h) and the first through hole (4h).

9. The motor according to any one of claims 1 to 5, characterized in that, Both the winding spool (3) and the connecting ring (4) are made of insulating material.

10. A power system for a vehicle, characterized in that, The motor included in any one of claims 1 to 9.

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