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EP-4145676-B1 - COOLING SYSTEM FOR DRIVING MOTOR OF NEW ENERGY AUTOMOBILE

EP4145676B1EP 4145676 B1EP4145676 B1EP 4145676B1EP-4145676-B1

Inventors

  • WANG, JIAN
  • HU, MENG
  • ZHANG, Hanni
  • HUANG, Shaorui
  • QU, Yaru

Dates

Publication Date
20260513
Application Date
20200426

Claims (12)

  1. A drive motor (1) of an alternative fuel vehicle including a cooling system, wherein said drive motor comprises a motor housing (2), a stator core (3) arranged in said motor housing (2), and a stator winding (4) arranged inside said stator core (3), wherein said stator core (3) is formed by a lamination of core punches (31, 32), said cooling system comprises: a flow guiding configuration (5) positioned at the outer periphery of said stator core (3), forming a connected space by means of a hole or slot in the outer periphery of said stator core (3) or in the inner wall of said motor housing (2) for directing the coolant flow at the outer periphery of said stator core (3) to cool said stator core (3), said flow guiding configuration (5) comprising alternately arranged diversion regions (51) and convergence regions (52), so that the coolant flow is subdivided into multiple paths and flows in parallel in the diversion regions (51) and converges into a single path in the convergence regions (52); one or more coolant inlets (8) arranged on said motor housing (2) in connection with said convergence regions (52), for introducing the coolant from outside said cooling system to the outer periphery of said stator core (3); a flow guiding hood (6) mounted in said motor housing (2), extending away from said stator core (3) from the end of said stator core (3) and gradually converging along the axial direction of said stator core (3), for directing the coolant flow to the end of said stator winding (4) to cool the end of said stator winding (4), wherein said flow guiding hood (6) covers only a portion of an upper part of an end of said stator core (3) along the vertical direction, and wherein said flow guiding hood (6) extends a distance along the axial direction of said stator core (3) less than the distance that said end of said stator winding (4) extends along the axial direction of said stator core (3) outside of said stator core (3); and a convergence port (9) positioned in the upper part of the end of said stator core (3) along the vertical direction, for allowing the passage of the coolant in said flow guiding configuration (5) to allow the coolant flow from the outer periphery of said stator core (3) to said flow guiding hood (6), characterized in that said flow guiding hood (6) is a hollow structure and comprises a plurality of diversion bosses (61) and a plurality of flow guiding strips (62) for uniformly dispersing the coolant flowing into said flow guiding hood (6) into a circumferential area inside said flow guiding hood (6) along the orientation of said flow guiding hood (6), wherein said flow guiding hood (6) is attached to an end pressure plate arranged on the end of said stator core (3), wherein said coolant in said flow guiding hood (6) flows from said stator core (3) via holes or slots arranged in said end pressure plate and flows in the direction of said stator winding (4) by the combined action of said diversion bosses (61), said flow guiding strips (62) and gravity, and wherein said end pressure plate is formed by a lamination of said core punches (31, 32).
  2. The drive motor (1) of an alternative fuel vehicle according to claim 1, wherein said cooling system further comprises: a flow accumulating hood (7) mounted in said motor housing (2) and attached to an end pressure plate on the end of said stator core (3), extending away from said stator core (3) from the end of said stator core (3) and gradually converging along the axial direction of said stator core (3), for receiving a portion of the coolant falling from the end of said stator winding (4), wherein said flow accumulating hood (7) only covers a portion of the lower part of the end of said stator core (3) along the vertical direction, said flow accumulating hood (7) extends along the axial direction of the stator core (3) for a greater distance than the end portion of said stator winding (4) extends along the axial direction of said stator core (3) outside said stator core (3); and a coolant outlet (10) arranged at the bottom of said flow accumulating hood (7) for exporting the coolant from said flow accumulating hood (7) to avoid prolonged immersion of the coolant in said drive motor during the cessation of operation of said drive motor, wherein said flow accumulating hood (7) is configured such that the coolant therein flows from said coolant outlet (10), or such that the coolant overflows from said flow accumulating hood (7) after filling said flow accumulating hood (7).
  3. The drive motor (1) of an alternative fuel vehicle according to claim 2, wherein said flow guiding strips (62) protrude from the interior of said flow guiding hood (6) along the inner surface of said flow guiding hood (6) and extend toward said flow accumulating hood (7) for causing the coolant passing through said diversion bosses (61) to flow along the orientation of said flow guiding hood (6) or said flow guiding strips (62) and fall to the end of said stator winding (4).
  4. The drive motor (1) of an alternative fuel vehicle according to any one of claims 1 to 3, wherein the coolant in said flow guiding hood (6) is distributed directly by a motor oil pump.
  5. The drive motor (1) of an alternative fuel vehicle according to any one of claims 1 to 3, wherein: said core punches (31, 32) are annular in shape, and said flow guiding configuration (5) is formed by a lamination of said core punches (31, 32) to allow coolant to flow around the outer perimeter of said core punches (31, 32).
  6. The drive motor (1) of an alternative fuel vehicle according to claim 5, wherein: adjacent said core punches (31, 32) are deflected by a first circumferential angle along the circumference direction of said stator core (3), and said core punches (31, 32) are arranged with tabs on their outer circumference for forming said diversion regions (51).
  7. The drive motor (1) of an alternative fuel vehicle according to claim 6, wherein: said diversion regions (51) comprise a plurality of sub-diversion regions, said tabs are centrally distributed in said plurality of sub-diversion regions, the number of said tabs included in each sub-diversion region is n being not less than 2, each of said tabs extends a second circumferential angle (α) along the circumferential direction, the angle between the corresponding sides of adjacent said tabs is a third circumferential angle (β), and the angle between adjacent said sub-diversion regions is a fourth circumferential angle (γ).
  8. The drive motor (1) of an alternative fuel vehicle according to claim 7, wherein: said cooling system is configured to satisfy: γ > (n - 1) * β + α, n ≥ 2, and said convergence regions (52) extend along the circumference direction at a circumferential angle not less than the fourth circumferential angle.
  9. The drive motor (1) of an alternative fuel vehicle according to claim 8, wherein adjacent said diversion regions (51) are spaced from each other at a circumferential angle for forming said convergence regions (52).
  10. The drive motor (1) of an alternative fuel vehicle according to claim 7, wherein: said core punches (31, 32) are arranged with slots for forming said convergence regions (52), said tabs arranged on said core punches (31, 32) extend in a circumferential direction and comprise a plurality of holes therein, said plurality of holes comprising a short hole (322) and a medium-length hole (323) for forming said diversion regions (51), the circumferential angle between adjacent said holes is a second circumferential angle (α), the circumferential angle of said short hole (322) is the difference between said third circumferential angle (β) and said second circumferential angle, and the circumferential angle of said mid-length hole is a fourth circumferential angle (γ).
  11. The drive motor (1) of an alternative fuel vehicle according to claim wherein: said core punches (31, 32) are arranged with two slots, said tabs extending in a circumferential direction from one said slot to the another said slot, said tabs comprising a short hole (322), a medium-length hole (323) and a long hole (324), said short hole (322) and said medium-length hole (323) are used for forming said diversion regions (51), said long hole (324) and said slot are used for forming said convergence regions (52), the circumferential angle between adjacent said holes in said tabs is a second circumferential angle (α), the circumferential angle of said short hole (322) is the difference between said third circumferential angle (β) and said second circumferential angle, and the circumferential angle of said mid-length hole is a fourth circumferential angle (γ).
  12. The drive motor (1) of an alternative fuel vehicle according to any one of claims 1 to 3, wherein said flow guiding configuration (5) comprises tabs machined on the inner side of said motor housing (2) to allow coolant to flow on the inner side of said motor housing (2).

Description

FIELD OF THE INVENTION The present invention relates to a cooling system for a drive motor, and specifically to a cooling system for a drive motor for an alternative fuel vehicle. BACKGROUND OF THE INVENTION Alternative fuel vehicles have become the mainstream direction of future automotive technology development, with the rapid development of alternative fuel vehicle drive technology, the market has gradually increased the requirements for all aspects of the alternative fuel vehicle drive system. As one of the core components of the drive system, the drive motor needs to meet the increasingly stringent vehicle drive requirements under the condition of continuously reducing the size, weight and cost, which poses a huge challenge to the cooling system of the drive motor. Conventional drive motor cooling methods are water-cooled or oil-cooled. In the water-cooled solution, the coolant does not come into direct contact with the heat-generating parts of the drive motor, and the cooling efficiency is low, which is not suitable for high power density drive motors. In the oil-cooled solution, the cooling oil is sprayed to the end of the stator winding of the drive motor through the oil hole of the oil injection tube, and the heat of the stator winding of the drive motor is directly removed, and the cooling efficiency is high. However, the distribution of the oil holes on the oil injection tube and its own processing accuracy will affect the oil injection efficiency of the oil injection tube, which in turn directly affects the cooling effect of the cooling oil on the drive motor. In addition, how to guarantee the sealing effect at the entrance of the oil injection tube has become one of the challenges in the oil cooling solution. CN203747551U discloses a liquid-cooled housing for an electric bus drive motor. The housing includes an inner cylinder, an outer cylinder, and a liquid-cooled chamber between the inner cylinder and the outer cylinder. A water inlet and a water outlet are arranged on the outer cylinder. A plurality of tendons are arranged along the axial direction between the inner barrel and the outer barrel. The fascia divides the liquid-cooled chamber into a plurality of interoperable circulation waterways. A ridge-shaped heat sink is arranged in this circulation waterway. CN104518614A discloses a liquid-cooled cooling device for a drive motor. The cooling device includes: a first housing body, a second housing body, a water inlet and a water outlet. A plurality of cavities are arranged between an inner wall and an outer wall of the first housing body in an axial direction. A recess for connecting adjacent cavities is arranged on the end face of the first housing body. The adjacent recesses are located at different ends of the first housing body to form an S-shaped channel together with the plurality of cavities. A plurality of hollow projections are arranged on the outer side of the inner wall and on the inner side of the outer wall of the first housing body. In summary, reducing the size and weight of the drive motor, improving the cooling capacity and reliability of the cooling system as well as reducing the cost of the cooling system are the technical problems to be solved. JP2009022145A and US2011/234029A1 disclose drive motors with a cooling system comprising diversion regions and convergence regions. SUMMARY In order to solve the above technical problems, the present application discloses a cooling system for a drive motor of an alternative fuel vehicle, the features of which are recorded in the claims. Based on the requirement of miniaturization and light weight of drive motors for alternative fuel vehicles, this application proposes a cooling solution in which the coolant directly contacts the stator core and the end of the stator winding. This application removes the additional cooling housing used in the cooling system of a conventional drive motor, allowing the cooling capacity to be increased and the size of the motor to be reduced. Based on the requirement of reliability of drive motors for alternative fuel vehicles, in this application, the stator is formed by a lamination of the core punch, which ensures uniform coolant shunting while reducing the flow resistance of the coolant. The cooling structure for the end of the stator winding consists of a combination of a flow guiding hood and an flow accumulating hood, which is open cooling without strict sealing requirements and without the risk of clogging. The combination of the two increases the reliability of the cooling system. Based on the low-cost requirements of drive motors for alternative fuel vehicles, in this application, the direct cooling structure is formed by staggering the core punches without additional machining of the stator, and the proposed direct cooling structure for the stator requires only up to two different core punches and no separate cooling housing, which makes the mechanical structure simpler and does not require