Oil cooling driving motor with diversion cooling structure

Abstract

The invention discloses an oil cooling driving motor with a diversion cooling structure, which comprises a motor shell, a stator core, a stator winding, a speed reducer shell, a front oil injection ring and a rear oil injection ring, and is characterized in that the front oil injection ring is arranged between the front end of the stator core and the speed reducer shell, and the rear oil injection ring is arranged between the rear end of the stator core and the rear end of the motor shell; a plurality of oil injection holes are formed in the front oil injection ring and the rear oil injection ring in the circumferential direction at intervals. The upper parts of the inner sides of the front oil injection ring and the rear oil injection ring are respectively provided with a flow guide structure corresponding to each oil injection hole; an oil return hole and an oil return channel are formed in the bottom of the motor shell, and the oil return hole is communicated with the inner cavity of the speed reducer shell through the oil return channel. The cooling effect on the stator end winding under the working condition of small flow of cooling oil can be ensured, so that the cooling performance of the oil-cooled driving motor is improved, and the reliability and stability of operation of the driving motor are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of motor cooling, and in particular to an oil-cooled drive motor with a flow-guiding cooling structure. Background Art

[0002] With the rapid development of new energy vehicles, the drive motors of new energy vehicles are currently developing towards high speed, high power density, and high integration. The heat generated by their work is getting larger and more concentrated, resulting in higher and higher heat loss of the motors. Therefore, the heat dissipation and cooling structure of the drive motors play an important role in the safe and stable operation of the drive motors. The cooling of the drive motors can be divided into air cooling, water cooling, and oil cooling. Among them, oil cooling has become the mainstream of high-performance drive motor cooling solution design due to its good insulation performance and flexibility of cooling structure design.

[0003] Although there are many new energy motors that use oil cooling in the prior art, in actual working process, the cooling of the stator winding end of the existing drive motor is achieved by spraying the oil spray holes of the oil spray ring to the stator winding end. However, under the condition of a small flow rate of cooling oil, the cooling oil slowly flows out from the oil spray holes on the oil spray ring and cannot form a spray effect. The cooling oil flowing out of the oil spray holes flows downward along the circumferential surface of the oil spray ring and cannot flow to the stator end winding to cool the stator end winding, resulting in a technical problem of poor cooling effect of the stator end winding. The stator end winding is prone to local temperature rise exceeding the standard, which directly affects the performance of the drive motor and even seriously affects the reliability and stability of the drive motor operation.

[0004] Therefore, it is urgent to design a cooling structure that can achieve better cooling effect under low cooling oil flow conditions to solve the technical problems existing in the prior art. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to solve the problem in the prior art that the cooling effect is poor under the condition of small flow rate of cooling oil, resulting in poor reliability and stability of the drive motor, and to provide an oil-cooled drive motor with a guide cooling structure, which can ensure the cooling effect of the stator end winding under the condition of small flow rate of cooling oil, thereby improving the cooling performance of the oil-cooled drive motor, and further ensuring the reliability and stability of the drive motor operation.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: an oil-cooled drive motor with a guide cooling structure, comprising a motor housing, a motor shaft, a rotor core, a stator core, a stator winding, a reducer housing and an oil spray ring; characterized in that: the oil spray ring comprises a front oil spray ring and a rear oil spray ring, the front oil spray ring is arranged between the front end of the stator core and the reducer housing, and is located on the front outer side of the stator winding, and the motor housing, the reducer housing, the front oil spray ring and the stator core jointly form a first annular oil chamber; the rear oil spray ring is arranged between the rear end of the stator core and the rear end of the motor housing, and is located on the rear outer side of the stator winding, and the motor housing, the rear oil spray ring and a second oil chamber in the shape of an annular ring is formed between the stator core; an oil inlet hole is provided on the reducer housing, and the oil inlet hole is connected with the first oil chamber through an oil inlet channel, and a plurality of oil channels are provided around the stator core, and the first oil chamber is connected with the second oil chamber through the oil channel; a plurality of oil injection holes are provided on the front injection ring and the rear injection ring at intervals along the circumference thereof; a guide structure is provided at the upper part of the inner side of the front injection ring and the rear injection ring corresponding to each oil injection hole, and the cooling oil can be guided to the front end and the rear end of the stator winding through the guide structure; an oil return hole and an oil return channel are provided at the bottom of the motor housing, and the oil return hole is connected with the inner cavity of the reducer housing through the oil return channel.

[0007] Furthermore, the axial direction of the oil injection hole corresponds to the radial direction of the front oil injection ring and the rear oil injection ring.

[0008] Furthermore, the numbers of the injection holes on the front injection ring and the rear injection ring are 9 to 21 respectively.

[0009] Furthermore, the total flow cross-sectional area of ​​the injection holes on the front injection ring and the rear injection ring is 22 ~ 34mm 2 .

[0010] Furthermore, the relationship between the total flow cross-sectional area A1 of the injection holes on the front injection ring, the total flow cross-sectional area A2 of the injection holes on the rear injection ring, the length L1 of the front end of the stator winding, and the length L2 of the rear end of the stator winding is: 0.95*L1 / L2≤A1 / A2≤L1 / L2.

[0011] Furthermore, among the guide structures on the front fuel injection ring and the rear fuel injection ring, the angles between the diameters of the guide structures at the bottom on both sides of the front fuel injection ring and the rear fuel injection ring and the vertical diameters of the front fuel injection ring and the rear fuel injection ring are both 0° to 80°.

[0012] Furthermore, the cross section of the guide structure is in the shape of a semicircle, an arc-shaped groove plate or a thin plate.

[0013] Furthermore, the distance between the guide structure on the front injection ring and the circumferential surface of the front end of the stator winding, and the distance between the guide structure on the rear injection ring and the circumferential surface of the rear end of the stator winding are both greater than or equal to 1 mm.

[0014] Furthermore, sealing rings are provided between the front oil injection ring and / or the rear oil injection ring and the stator core, between the front oil injection ring and the reducer housing, and between the rear oil injection ring and the inner wall of the motor housing.

[0015] Compared with the prior art, the present invention has the following advantages: 1. By setting a front oil injection ring and a rear oil injection ring, and opening oil injection holes on the front oil injection ring and the rear oil injection ring, the front end and the rear end of the stator winding can be sprayed and cooled synchronously, thereby ensuring that the two ends of the stator winding can be cooled synchronously and improving the cooling effect of the drive motor.

[0016] 2. Since the lengths of the ends of the stator winding extending out of the stator core are different, the heat generated at the two ends of the winding is also different, and the oil temperatures of the cooling oil sprayed by the front injection ring and the rear injection ring are also different. Therefore, the relationship between the total flow cross-sectional area of ​​the injection holes on the front injection ring and the total flow cross-sectional area of ​​the injection holes on the rear injection ring can reasonably allocate the injection amount of the front injection ring and the rear injection ring, thereby making the cooling effect of the two ends of the motor stator winding more consistent.

[0017] 3. Under the condition of small cooling oil flow, based on the Coanda effect principle, multiple guide structures are arranged along the circumference of the injection ring below the multiple injection holes in the upper half of the injection ring. The cooling oil slowly flows out from the injection holes on the injection ring and drips onto the surface of the stator end winding under the drainage action of the guide structure to cool the stator end winding. This solves the problem that the cooling oil cannot flow through the stator end winding for cooling under small flow conditions, and improves the cooling effect of the drive motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the exploded structure of the oil-cooled drive motor in an embodiment of the present invention.

[0019] Figure 2 It is a central cross-sectional view of an oil-cooled drive motor in an embodiment of the present invention.

[0020] Figure 3 A schematic structural diagram of a stator core and a stator winding in an embodiment of the present invention.

[0021] Figure 4 Schematic diagram of an oil injection ring in an embodiment of the present invention.

[0022] Figure 5 Schematic diagram of the flow guide structure on the oil injection ring in an embodiment of the present invention.

[0023] Figure 6 A front view of an oil injection ring in an embodiment of the present invention.

[0024] Figure 7 Schematic diagram of the position of the oil injection ring and the stator end winding in an embodiment of the present invention.

[0025] Figure 8 Book Figure 7 Enlarged view of part A in the figure.

[0026] In the figure: 1—motor housing, 2—stator core, 3—stator winding, 4—reducer housing, 51—front oil injection ring, 52—rear oil injection ring, 61—first oil chamber, 62—second oil chamber, 7—oil inlet hole, 8—oil inlet channel, 9—oil injection hole, 10—oil return hole, 11—oil return channel, 12—flow guide structure. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] Example: See Figures 1 to 3 , an oil-cooled drive motor with a flow-guiding cooling structure, comprising a motor housing 1, a motor shaft, a rotor core, a stator core 2, a stator winding 3, a reducer housing 4 and an oil injection ring. The oil injection ring comprises a front oil injection ring 51 and a rear oil injection ring 52. The front oil injection ring 51 is arranged between the front end of the stator core 2 and the reducer housing 4, and is located outside the front end of the stator winding 3; and the motor housing 1, the reducer housing 4, the front oil injection ring 51 and the stator core 2 together form a first annular oil chamber 61. A sealing ring is arranged between the front oil injection ring 51 and the reducer housing 4 and the stator core 2; an oil inlet hole 7 is arranged on the reducer housing 4, and the oil inlet hole 7 is connected to the first oil chamber 61 through an oil inlet channel 8. The rear injection ring 52 is arranged between the rear end of the stator core 2 and the rear end of the motor housing 1, and is located outside the rear end of the stator winding 3; and the inner wall of the motor housing 1, the rear injection ring 52 and the stator core 2 together form a second oil chamber 62 in an annular shape. Among them, sealing rings are provided between the rear injection ring 52 and the stator core 2, and between the rear peripheral surface of the rear injection ring 52 and the motor housing 1. A plurality of oil passages are provided around the stator core 2, and the first oil chamber 61 is connected to the second oil chamber 62 through the oil passages; during implementation, a plurality of grooves are distributed around the outer wall of the stator core 2, and the grooves pass through the two ends of the stator core 2; during assembly, the stator core 2 is fixedly connected to the motor housing 1, so that the motor housing 1 closes the grooves to form the oil passages.

[0029] A plurality of oil injection holes 9 are provided at intervals along the circumference of the front oil injection ring 51 and the rear oil injection ring 52. In a specific implementation, the axial direction of the oil injection holes 9 corresponds to the radial direction of the front oil injection ring 51 and the rear oil injection ring 52. In this way, when the pressure and flow rate of the cooling oil are relatively large, the front oil injection ring 51 and the rear oil injection ring 52 can spray and cool different positions of the circumference of the two ends of the stator winding 3 through the oil injection holes 9. The convection heat transfer coefficient between the cooling oil sprayed to the winding end and the end winding surface is high, and the cooling oil can take away more heat, which has a better cooling effect on the motor stator winding 3.

[0030] During the operation of the motor, the cooling oil is sprayed to the ends of the motor stator winding 3 through the oil injection holes 9 on the oil injection ring to cool and dissipate the heat of the ends of the stator winding 3 at the same time. The cooling oil flowing through the ends of the stator winding 3 flows back into the cavity of the reducer housing 4 through the oil return hole 10 and the oil return channel 11.

[0031] Preferably, if Figure 4 , Figure 5 As shown, during implementation, the oil-cooled drive motor is defined to have a height direction along the radial direction of the motor housing 1. At the upper part of the inner side of the front injection ring 51 and the rear injection ring 52, a guide structure 12 is provided corresponding to each injection hole 9, and the cooling oil can be directed to the front end and rear end of the stator winding 3 through the guide structure 12. During processing, the guide structure 12 is formed into one piece with the front injection ring 51 and the rear injection ring 52, or welded and fixed; and the cross-section of the guide structure 12 is semicircular, arc-shaped groove plate or thin plate; and it is located at the lower side of the corresponding injection hole 9, and the guide structure 12 is also arranged along the radial direction of the injection ring. Among them, the distance between the guide structure 12 on the front injection ring 51 and the circumference of the front end of the stator winding 3, and the distance between the guide structure 12 on the rear injection ring 52 and the circumference of the rear end of the stator winding 3 are both greater than or equal to 1mm.

[0032] When implementing it, Figure 7 and Figure 8 As shown, the minimum distance between the front injection ring 51 of the oil-cooled drive motor and the circumferential surface of the front end portion of the stator winding 3 is a, and the height of the guide structure 12 on the front injection ring 51 is h1, (a-2) mm≤h1<amm; the minimum distance between the rear injection ring 52 and the circumferential surface of the rear end portion of the stator winding 3 is b, and the height of the guide structure 12 on the rear injection ring 52 is h2, (b-2) mm≤h2<b mm.

[0033] An oil return hole 10 and an oil return channel 11 are provided at the bottom of the motor housing 1 . The oil return hole 10 is connected to the inner cavity of the reducer housing 4 through the oil return channel 11 .

[0034] By adopting this solution, under the condition of a small cooling oil flow rate, the cooling oil slowly flows out from the injection hole 9 on the injection ring, and then flows downward along the circumferential surface of the injection ring. Based on the Coanda effect principle, the cooling oil slowly flows downward along the circumferential surface of the injection ring and drips onto the surface of the stator end winding under the drainage action of the guide structure 12, thereby cooling the stator end winding. This solves the problem that the cooling oil cannot flow through the stator end winding for cooling under a small flow rate condition, thereby improving the cooling effect of the drive motor.

[0035] In a specific implementation, among the guide structures 12 on the front fuel injection ring 51 and the rear fuel injection ring 52, the angle between the diameter of the guide structure 12 located at the bottom of both sides of the front fuel injection ring 51 and the rear fuel injection ring 52 and the vertical diameter of the front fuel injection ring 51 and the rear fuel injection ring 52 is 0° to 80°. Figure 5 , Figure 6 As shown, the front injection ring 51 is provided with a guide structure 12 within an angle range of α1 rotated counterclockwise from directly above along the circumferential direction, 0°≤α1≤80°; the front injection ring 51 is provided with a guide structure 1215 within an angle range of α2 rotated clockwise from directly above along the circumferential direction, 0°≤α2≤80°. The rear injection ring 52 is provided with a guide structure 1215 within an angle range of β1 rotated counterclockwise from directly above along the circumferential direction, 0°≤β1≤80°, and the rear injection ring 52 is provided with a guide structure 1215 within an angle range of β2 rotated clockwise from directly above along the circumferential direction, 0°≤β2≤80°.

[0036] In specific implementation, the number of the oil injection holes 9 on the front oil injection ring 51 and the rear oil injection ring 52 is 9 to 21; wherein, the number of the oil injection holes 9 on the front oil injection ring 51 and the rear oil injection ring 52 can be the same or different; preferably, the number of the oil injection holes 9 on the rear oil injection ring 52 is greater than the number of the oil injection holes 9 on the front oil injection ring 51. In this way, a better cooling oil spraying speed can be obtained, and the cooling oil sprayed by the oil injection holes 9 can also cover the end surface of the motor stator winding 3, reducing or avoiding the problem of excessive temperature rise caused by the difficulty of the cooling oil in covering the end surface of the stator winding 3. If the number of oil injection holes 9 on the oil injection ring is too small and the intervals between the oil injection holes 9 on the oil injection ring are too large, only a partial area of ​​the end of the motor stator winding 3 will be covered by the cooling oil spray, and the winding position where the cooling oil does not flow through will easily have a temperature rise problem exceeding the standard; if the number of oil injection holes 9 on the oil injection ring is too large and the total flow cross-sectional area of ​​the oil injection holes 9 is too large, the spraying speed of the oil injection holes 9 will be too low, and the cooling oil sprayed by the oil injection holes 9 on the upper part of the oil injection ring will be drained through the guide structure 12, slowly flow and drip to the end of the stator winding 3 for cooling, but the cooling oil sprayed by the oil injection holes 9 in the middle and lower part of the oil injection ring cannot reach the end of the stator winding 3, and the cooling effect is poor.

[0037] In addition, the total flow cross-sectional area of ​​the injection holes 9 on the front injection ring 51 and the rear injection ring 52 is 22 to 34 mm.2 . In this way, the contact area between the cooling oil and the winding surface and the cooling and heat exchange effect can be guaranteed. If the total flow cross-sectional area of ​​the oil injection holes 9 on the oil injection ring is too small, and the spraying speed of the oil injection holes 9 is too high, the cooling oil will be splashed back after being sprayed onto the winding surface, and the contact area between the cooling oil and the winding will be reduced, the contact time will be short, and the cooling performance will be poor; if the total flow cross-sectional area of ​​the oil injection holes 9 on the oil injection ring is too large, and the spraying speed of the oil injection holes 9 is too small, the cooling oil sprayed from the oil injection holes 9 on the upper part of the oil injection ring will be drained through the guide structure 12, slowly flow and drip to the end of the stator winding 3 for cooling, and the cooling oil sprayed from the oil injection holes 9 in the lower part of the oil injection ring will not be able to reach the end surface of the stator winding 3, and will not be able to cool the end of the stator winding 3.

[0038] Preferably, the total flow cross-sectional area A1 of the injection holes 9 on the front injection ring 51, the total flow cross-sectional area A2 of the injection holes 9 on the rear injection ring 52, the length L1 of the front end of the stator winding 3, and the length L2 of the rear end of the stator winding 3 satisfy the relationship: 0.95*L1 / L2≤A1 / A2≤L1 / L2. This can reduce the problem of uneven cooling of the motor stator end winding and poor cooling effect, and improve the overall cooling effect of the drive motor. The temperature of the cooling oil sprayed by the injection holes 9 on the front injection ring 51 is lower than the temperature of the cooling oil sprayed by the injection holes 9 on the rear injection ring 52. When the heat generated by the end of the first stator winding 3 and the end of the second stator winding 3 are the same, the amount of oil sprayed required by the end of the first stator winding 3 is small, and the total flow cross-sectional area required by the multiple injection holes 9 on the front injection ring 51 is small; the longer the length of the end of the stator winding 3, the greater the heat generated by the end of the stator winding 3, the more oil sprayed is required, and the larger the total flow cross-sectional area of ​​the required injection holes 9 is. Since the lengths of the ends of the stator winding 3 extending out of the stator core 2 are different, the heat generated at the two ends of the winding are also different, and the oil temperatures of the cooling oil sprayed by the front injection ring 51 and the rear injection ring 52 are also different. Therefore, the relationship between the total flow cross-sectional area of ​​the injection holes 9 on the front injection ring 51 and the total flow cross-sectional area of ​​the injection holes 9 on the rear injection ring 52 can reasonably allocate the injection amounts of the front injection ring 51 and the rear injection ring 52, thereby making the cooling effect of the two side ends of the motor stator winding 3 more consistent.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. An oil-cooled drive motor with a flow-conducting cooling structure, comprising a motor housing (1), a motor shaft, a rotor core, a stator core (2), a stator winding (3), a reducer housing (4) and an oil injection ring; characterized in that: The oil injection ring comprises a front oil injection ring (51) and a rear oil injection ring (52); the front oil injection ring is arranged between the front end of the stator core and the reducer housing, and is located outside the front end of the stator winding, and the motor housing, the reducer housing, the front oil injection ring and the stator core together form a first annular oil chamber (61); the rear oil injection ring is arranged between the rear end of the stator core and the rear end of the motor housing, and is located outside the rear end of the stator winding, and the motor housing, the rear oil injection ring and the stator core together form a second annular oil chamber (62); an oil inlet hole (7) is provided on the reducer housing, and the oil inlet hole passes through The oil inlet passage (8) is connected to the first oil chamber, and a plurality of oil passages are arranged around the stator core, and the first oil chamber is connected to the second oil chamber through the oil passages; a plurality of oil injection holes (9) are arranged at intervals along the circumference of the front oil injection ring and the rear oil injection ring; a guide structure (12) is arranged at the upper part of the inner side of the front oil injection ring and the rear oil injection ring corresponding to each oil injection hole, and the cooling oil can be guided to the front end and the rear end of the stator winding through the guide structure; an oil return hole (10) and an oil return passage (11) are arranged at the bottom of the motor housing, and the oil return hole is connected to the inner cavity of the reducer housing through the oil return passage.

2. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 1, characterized in that: The axial direction of the oil injection hole corresponds to the radial direction of the front oil injection ring and the rear oil injection ring.

3. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 2, characterized in that: The number of injection holes on the front injection ring and the rear injection ring are 9 to 21 respectively.

4. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 2, characterized in that: The total cross-sectional area of ​​the injection holes on the front and rear injection rings is 22 ~ 34mm 2 .

5. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 2, characterized in that: The relationship between the total flow cross-sectional area A1 of the injection holes on the front injection ring, the total flow cross-sectional area A2 of the injection holes on the rear injection ring, the length L1 of the front end of the stator winding, and the length L2 of the rear end of the stator winding is: 0.95*L1 / L2≤A1 / A2≤L1 / L2.

6. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 1, characterized in that: In the guide structures on the front fuel injection ring and the rear fuel injection ring, the angles between the diameters of the guide structures at the bottom on both sides of the front fuel injection ring and the rear fuel injection ring and the vertical diameters of the front fuel injection ring and the rear fuel injection ring are both 0° to 80°.

7. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 1, characterized in that: The cross section of the flow-guiding structure is in the shape of a semicircle, an arc-shaped slot plate or a thin plate.

8. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 1, characterized in that: The distance between the guide structure on the front injection ring and the circumferential surface of the front end of the stator winding, and the distance between the guide structure on the rear injection ring and the circumferential surface of the rear end of the stator winding are both greater than or equal to 1 mm.

9. The oil-cooled drive motor with a flow-conducting cooling structure according to claim 1, characterized in that: Sealing rings are provided between the front oil injection ring and / or the rear oil injection ring and the stator core, between the front oil injection ring and the reducer housing, and between the rear oil injection ring and the inner wall of the motor housing.

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