Integrated Drive System

Abstract

To provide an efficient cooling system for an integrated drive system in which an inverter, an electric motor, and a gearbox are provided in the same housing.SOLUTION: An integrated drive system (100) includes an electric motor (120) having a stator (129) and a rotor, an inverter (110) for controlling the electric motor (120), a gearbox (130) for transmitting torque supplied by the electric motor, and a cooling system. The cooling system has a cooling liquid flowing through a cooling channel for cooling the inverter (110), the rotor, the stator (129) and the gearbox (130).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an integrated drive system comprising an electric motor, an inverter, and a gearbox. [Background technology]

[0002] In recent years, technology related to electric vehicles and hybrid vehicles, which are vehicles powered by electricity, has been rapidly developing. An electric vehicle or hybrid vehicle may include an electric motor that generates rotational force, an inverter that controls the electric motor, a battery that supplies power to the inverter, and a gearbox that transmits torque from the electric motor to the vehicle's wheels. To limit the size of these components within a vehicle, more and more research is being conducted into how to arrange these components. To this end, it is known to provide an integrated drive system that integrates these components into a single device mounted on the vehicle. For example, US9030063B2 proposes integrating an electric motor, an inverter, and a gearbox into a single housing. Summary of the Invention [Problem to be solved by the invention]

[0003] A major problem in electric and hybrid vehicles remains how to efficiently cool the components of the integrated drive system. US9030063B2 proposes a cooling system in which a cooling path is divided into a first cooling path for cooling the motor rotor and gearbox and a second cooling path for cooling the motor stator and inverter. However, this parallel cooling method requires a manifold at the position where the cooling path branches into the first and second cooling paths, and also requires control of the coolant flow rate in each cooling path. This makes the implementation of this prior art integrated drive system difficult.

[0004] Therefore, there is a need for an integrated drive system that is easier to implement while still providing efficient cooling of its components. [Means for solving the problem]

[0005] The present invention relates to an integrated drive system including an electric motor having a stator and a rotor, an inverter for controlling the electric motor, a gearbox for transmitting torque supplied from the electric motor, and a coolant system including a coolant flowing through a single cooling passage for cooling the inverter, the rotor, the stator, and the gearbox.

[0006] Therefore, the integrated drive system of the present invention provides cooling for the inverter, motor, and gearbox through a single cooling path, and therefore does not require complex derivations, simplifying the design of the system of the present invention.

[0007] An integrated drive system refers to a system in which the inverter, electric motor, and gearbox are located together in the same housing, which may be formed, for example, from multiple parts. The integrated drive system thus forms a single entity that allows the inverter, electric motor, and gearbox to operate together simultaneously. Such an integrated drive system allows all of these components to be integrated into the vehicle's drivetrain at the same time.

[0008] According to one embodiment, the coolant sequentially cools the inverter, rotor, stator, and gearbox. The temperature sensitive components are ordered from most affected to least affected: inverter, rotor, stator, and gearbox. By cooling the most affected components first, the coolant cools these components while still at a lower temperature than at the outlet, thereby providing more heat dissipation to the components that need it most.

[0009] Advantageously, the cooling path comprises a series of sections, including a first section for cooling the inverter, a second section for cooling the rotor, a third section for cooling the stator, and a fourth section for cooling the gearbox, through which the coolant flows in sequence. In particular, a cooling path is formed at each component of the integrated drive system to cool each component in close proximity.

[0010] According to one embodiment, the gearbox comprises a lubrication circuit for receiving lubricating oil, the lubrication circuit being fluidly independent of the cooling system and thermally connected to it. Advantageously, the coolant passes through a heat exchanger that allows heat exchange between the coolant and the lubricating oil. This limits the penetration of the cooling system into the gearbox. Long cooling channels within the gearbox are not necessary. The lubricating oil is cooled. It is then injected into hot spots in the gearbox.

[0011] According to one aspect of the invention, an electric motor comprises a case that houses a rotor and a stator, the case having a cylindrical side extending along the axis of the electric motor to house the stator, a first end at a first axial end of the electric motor that closes the first axial end of the side and forms a so-called B shield, and a second end at a second axial end of the electric motor opposite the first axial end of the electric motor that closes the second axial end of the side and forms a so-called A shield.

[0012] According to a variant, the A-shield is also part of the gearbox case. Therefore, the A-shield is shared between the electric motor case and the gearbox case. In particular, the A-shield of the electric motor has a concave shape facing away from the electric motor side to receive the gearbox components and form the gearbox case. Therefore, the gearbox is at least partially located on the A-shield of the electric motor.

[0013] According to one embodiment, an electric motor has a hollow rotor shaft to which a rotor is fixedly mounted. The rotor shaft has an interior space extending along the axis of the rotor shaft and adapted to receive a coolant for cooling the rotor. The B-shield includes a first passage for transmitting the coolant to the rotor shaft and a second passage communicating with the cooling passages of the stator for transmitting the coolant from the rotor to the cooling passages of the stator. The second passage routes the coolant to the stator for cooling the stator. Integrating the second passage into the B-shield improves integration of the cooling system into components of an integrated drive system.

[0014] Advantageously, the B shield includes a peripheral portion integral with the side of the case, axially facing the stator, and a central portion separate from the peripheral portion, axially facing the rotor shaft, and sealingly connected to the peripheral portion. The first and second flow passages each have a first portion formed in the central portion of the shield and a second portion formed in the peripheral portion of the B shield. By integrating the first and second flow passages into both the peripheral and central portions, the electric motor can be smaller in size than if the first and second flow passages were integrally formed in the central portion. In such a case, the flow passages must cross the peripheral portion while traversing the surface of the peripheral portion, which increases the size of the electric motor along the axis of the electric motor. Furthermore, the central portion can be removable, serving as a service cover for replacing elements within the rotor or rotor shaft, such as seals.

[0015] According to one embodiment, the case of the electric motor comprises a portion, called an extension, extending from the side of the case of the electric motor in a direction transverse to, in particular perpendicular to, the axis of the electric motor, from a position close to the B-shield to a position remote from the B-shield, which in particular corresponds to the axis of the rotor shaft of the electric motor.

[0016] Advantageously, the gearbox transmits torque from the rotor shaft of the electric motor to an output location. The output location is spaced apart from the electric motor relative to the axis of the rotor shaft. The extension extends from a side of the electric motor case opposite the output location of the gearbox and includes a hole for receiving a second shaft connected to the output location of the gearbox. Thus, the system includes a second shaft different from the rotor shaft. Specifically, the second shaft is supported at one end by the gearbox at the output location of the gearbox to receive torque from the gearbox, and at the other end by the extension. Thus, the second shaft is an outlet of the gearbox. Specifically, at the end supported by the extension, the second shaft can be connected to a vehicle drivetrain. This allows the integrated drive system to transmit torque from the gearbox to both axial ends of the integrated drive system, thereby facilitating integration of the integrated drive system into the vehicle drivetrain. To connect the vehicle drivetrain to the integrated drive system, it is only necessary to connect the end of the second shaft located at the extension on the one hand and the output location of the gearbox on the side of the gearbox that is not facing the extension on the other hand. A differential gear may be arranged at the output of the gearbox to transmit torque to the left and right wheels of the vehicle, on the one hand via the second shaft and on the other hand via the output on the side of the gearbox opposite the extension.

[0017] Advantageously, the inverter comprises a case carrying the inverter components, the case being supported on the electric motor case such that the outer surface of the inverter case extends in a plane tangent to the outer surface of the side of the electric motor case. The outer surface of the inverter case, the side of the electric motor case, the extension of the motor case, and the gearbox define a volume for receiving connecting ducts of a cooling system connecting the inverter, the electric motor, and the gearbox. In particular, these connecting ducts extend only within this volume. Therefore, these connecting ducts are unlikely to be damaged during installation in the drivetrain. In fact, the inverter case, the extension, the side of the electric motor case, and the gearbox at least partially protect the connecting ducts. In particular, the connecting ducts are not included in the electric motor case, the gearbox case, and the inverter case.

[0018] Advantageously, the inlet of the rotor cooling passage is located in the extension and a first duct connects the outlet of the inverter cooling passage to the inlet of the rotor cooling passage. In particular, these inlets and outlets are located in a volume defined by the outer surface of the inverter case, the side of the electric motor case, the extension of the electric motor case and the gearbox. This improves the protection of the cooling system.

[0019] Advantageously, the second duct connects the boundary of the stator cooling passage with the boundary of the gearbox cooling passage, the boundary of the stator cooling passage and the boundary of the gearbox cooling passage being located in a volume defined by the outer surface of the inverter case, the side of the electric motor case, the extension of the electric motor case and the gearbox, thus improving protection of the cooling system.

[0020] Advantageously, the extension comprises a boundary port of the cooling system, and the third duct connects the boundary of the gearbox cooling passage to the boundary port of the cooling system. In particular, the third duct is located in a volume defined by the outer surface of the inverter case, the side of the electric motor case, the extension of the electric motor case, and the gearbox. Thus, protection of the cooling system is improved.

[0021] According to one embodiment, the inverter is mounted to the side of the electric motor case and extends from the gearbox to the B-shield. In particular, the dimension of the inverter along the electric motor axis is from the B-shield to the gearbox. Thus, the dimension of the integrated drive system along the electric motor axis is determined by the gearbox and the electric motor.

[0022] The invention also relates to an electric motor comprising a case housing a rotor and a stator, the case having a cylindrical side extending along the axis of the electric motor to house the stator, a first end at a first axial end of the electric motor that closes the first axial end of the side and forms a so-called B shield, and a second end at a second axial end of the electric motor opposite the first axial end of the electric motor that closes the second axial end of the side and forms a so-called A shield, and that receives a gearbox.

[0023] The electric motor may have any of the features of the electric motors described above.

[0024] The invention also relates to electric and hybrid vehicles equipped with the integrated drive system described above.

[0025] The details of one or more embodiments are set forth in the accompanying drawings and the description below. The accompanying drawings are as follows: [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a perspective view of an integrated drive system according to an embodiment of the present invention. [Figure 2]FIG. 2 is an axial view of the integrated drive system of FIG. [Figure 3] FIG. 3 is a cross-sectional view of the electric motor of the integrated drive system of FIG. [Figure 4] FIG. 4 is a partial side view of the embodiment of FIG. [Figure 5] FIG. 5 is a partial perspective view of the embodiment of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0027] The drawings illustrate an exemplary integrated drive system 100 according to one embodiment of the present invention. The integrated drive system 100 comprises an electric motor 120, an inverter 110, and a gearbox 130. The inverter 110 is configured to control the electric motor 120, particularly via a battery. The gearbox 130 is configured to transmit torque provided by the electric machine 110.

[0028] Alternatively, the integrated drive system 100 may include a cooling system in which coolant flows along a single cooling path to cool the inverter 110, the electric motor 120, and the gearbox 130. Specifically, the cooling system sequentially cools the inverter 110, the electric motor 120, and the gearbox 130. To this end, the cooling system may be arranged as follows: The cooling system may include an inlet port 210 that receives coolant from outside the integrated drive system 100. The inlet port 210 is connected to a first cooling path section that passes through the inverter 110. A first connecting duct 215 connects the outlet of the first cooling path section to an inlet 217 of a second cooling path section that passes through the rotor of the electric motor 120. Specifically, the first connecting duct 215 is connected to a first flow path 124 inside the case 120c of the electric motor 120. The first flow path 124 supplies coolant to a rotor shaft 126 of the electric motor 120. A second flow passage 128 inside the casing 120c of the electric motor 120 supplies coolant to a third cooling path section 218 that cools a stator 129 of the electric motor 120. A second connecting duct 219 then connects the outlet of the third cooling path section 218 to the inlet 220 of a fourth cooling path section that cools the gearbox 130.

[0029] Specifically, gearbox 130 may be cooled by heat transfer between the fourth cooling path section and a lubrication circuit of gearbox 130. Such lubrication circuit receives cooled lubricant that is then injected into hot spots of gearbox 130 and flowed through the internal volume of the casing of gearbox 130. Such heat exchange between the coolant and the lubricant may be achieved by heat exchanger 132.

[0030] The outlet 222 of the fourth cooling path section is connected at the back by a third connecting duct 223 with the outlet port 224 of the cooling system.

[0031] In particular, the case 120c of the electric motor 120 houses the rotor and stator 129 of the electric motor 120. In particular, the case 120c has a cylindrical side 121c. The side 121c extends along the axis Δ of the electric motor 120 and houses the stator 129. A first end 122c located at a first axial end of the electric motor 120 forms a so-called B shield that closes the first axial end of the side 121c. A second end 123c of the case 120c forms a so-called A shield that closes the second axial end of the side 121c. The gearbox 130 is located on the A shield 123c of the electric machine 120. In particular, the A shield 123c is also part of the case 120c of the gearbox 130. In particular, the A shield 123c of the electric motor 120 has a concave shape facing away from the electric motor 120 side. In its concave shape, the A-shield 123c receives components of the gearbox 130.

[0032] Alternatively, the rotor shaft 126 may have a hollow space therein for receiving the coolant. This hollow space may extend over the entire axis Δ of the rotor shaft 126 so as to guide the coolant into the interior of the rotor shaft 126. This hollow space is in communication with the first flow passage 124 for receiving the coolant and with the second flow passage 128 for outputting the coolant to the side 121 c of the case 120 c of the electric motor 120.

[0033] In one variation, the B shield 122c includes a peripheral portion P that is integral with the side portion 121c of the case 120c and a central portion C that is separate from the peripheral portion P. The peripheral portion P axially faces the stator 129, and the central portion C axially faces the rotor shaft 126. A seal may be disposed at least at the boundary between the central portion C and the peripheral portion P to seal the interior space of the electric motor 120. Such a seal may be an O-ring. The first flow path 124 has a first portion 124C formed in the central portion C of the B shield 122c and a second portion 124P formed at the peripheral portion P of the B shield 122c. Similarly, the second flow path 128 has a first portion 128C formed in the central portion C of the B shield 122c and a second portion 128P formed at the peripheral portion P of the B shield 122c. This configuration makes the electric motor 120 more compact. Additionally, the central portion C is preferably removable, thereby allowing access to the interior of the electric motor 120, for example, for repairs.

[0034] Specifically, gearbox 130 transfers torque from rotor shaft 126 to output location 132. Output location 132 is spaced from electric motor 120 relative to axis Δ of rotor shaft 126.

[0035] In a variant, the case 120c of the electric motor 120 includes a portion 125c, referred to as an extension, extending from a side portion 121c of the case 120c of the electric motor 120. The extension 125c extends transversely, in particular perpendicularly, to the axis Δ of the rotor shaft 126 from a position close to the B shield 122c to a position far from the B shield 122c. In one variant, the extension 125c faces the output position 132 of the gearbox 130 with respect to the axis Δ and includes a hole 126c for receiving a second shaft 134 connected to the output position 132 of the gearbox 130.

[0036] Specifically, the inverter 110 may include a case 110c that contains the components of the inverter 110. In particular, the case 110c of the inverter 110 is supported on the case 120c of the electric motor 120 such that an outer surface 112c of the case 110c of the inverter 110 extends in a plane tangent to an outer surface of a side 121c of the case 120c of the electric motor 120.

[0037] As a variant, the outer surface 112c of the case 110c of the inverter 110, the side 121c of the case 120c of the electric motor 120, the extension 125c of the case 120c of the electric motor 120, and the gearbox 130 together define a volume in which the connecting ducts 215, 219, 223 of the cooling system are contained. In particular, these connecting ducts 215, 219, 223 are completely contained inside this defined volume. The connecting ducts 215, 219, 223 are therefore at least partially protected.

[0038] Advantageously, the inlet 217 of the second cooling path section, which passes through the rotor 129, is located in the extension 125c. In particular, the inlet 217 and the outlet of the first cooling path section are located within this defined volume. Likewise, advantageously, the outlet of the third cooling path section 218 and the inlet 220 of the fourth cooling path section are located within this defined volume. In particular, advantageously, the outlet port 224 of the cooling system is located in the extension 125c.

[0039] It should be understood that the present invention is not limited to the specific examples described above, and that integrated drive systems and electric motors within the scope of the present invention may be obtained from one or more combinations of the embodiments and variations described herein.

Claims

1. an electric motor (120) having a stator (129) and a rotor, an inverter (110) for controlling the electric motor (120), and a gearbox (130) for transmitting torque supplied from the electric motor (120); a cooling system including a cooling fluid flowing through cooling passages for cooling the inverter (110), the rotor, the stator (129), and the gearbox (130); An integrated drive system (100) comprising: The electric motor (120) comprises a case (120c) that houses the rotor and the stator (129); The case (120c) a cylindrical side portion (121c) extending along the axis of the electric motor (120) to accommodate the stator (129); a first end at the first axial end of the electric motor (120) forming a so-called B shield (122c) that closes the first axial end of the side part (121c); a second end portion at a second axial end of the electric motor (120) opposite to the first axial end of the electric motor (120), the second end portion forming a so-called A-shield (123c) that closes the second axial end of the side portion (121c), a hollow rotor shaft (126) to which the rotor is fixedly attached, the interior space of the rotor shaft (126) extending along the axis of the rotor shaft and receiving the coolant for cooling the rotor; The B shield (122c) includes a first flow path (124) that delivers the coolant to the rotor shaft, and a second flow path (128) that communicates with the cooling flow path of the stator (129) to deliver the coolant from the rotor to the cooling path of the stator (129).

2. The cooling liquid sequentially cools the inverter (110), the rotor, the stator (129), and the gearbox (130). The integrated drive system (100) of claim 1.

3. The cooling path comprises a continuous portion including a first portion for cooling the inverter (110), a second portion for passing through and cooling the rotor, a third portion for cooling the stator (129), and a fourth portion for cooling the gearbox (130). The integrated drive system (100) of claim 2.

4. The B shield (122c) is a peripheral portion (P) integral with the side portion (121c) of the case (120c) and axially facing the stator (129); a central portion (C) that is separate from the peripheral portion (P), faces the rotor shaft (126) in the axial direction, and is in a sealed relationship with the peripheral portion (P); 10. The integrated drive system (100) of claim 1, comprising: The integrated drive system (100) of any one of claims 1 to 3, wherein the first flow path (124) and the second flow path (128) each have a first portion (124C, 128C) formed in the central portion (C) of the B shield (122c) and a second portion (124P, 128P) formed in the peripheral portion (P) of the B shield.

5. 5. An integrated drive system according to claim 1, wherein the case of the electric motor comprises a portion, referred to as an extension, extending from the side of the case of the electric motor in a direction transverse to, and in particular perpendicular to, the axis of the electric motor from a position close to the B shield to a position far from the B shield.

6. the gearbox (130) transmits torque from the rotor shaft (126) of the electric motor (120) to an output location located remote from the electric motor (120) relative to the axis of the rotor shaft (126); 6. The integrated drive system of claim 5, wherein the extension portion extends from the side of the case of the electric motor opposite the output position of the gearbox and includes a hole for receiving a second shaft connected to the output position of the gearbox.

7. the inverter (110) comprises a case (110c) having components of the inverter (110), the case (110c) of the inverter (110) being supported on the case (120c) of the electric motor (120) such that an outer surface (112c) of the case (110c) of the inverter (110) extends in a plane tangent to an outer surface of a side (121c) of the case (120c) of the electric motor (120); 7. The integrated drive system of claim 6, wherein the outer surface of the case of the inverter, the side of the case of the electric motor, the extension of the case of the electric motor, and the gearbox define a volume for receiving a connecting duct of the cooling system that connects the inverter, the electric motor, and the gearbox.

8. 8. The integrated drive system (100) of claim 5, wherein an inlet of the cooling passage of the rotor is located in the extension (125c), and a first duct (215) connects an outlet of the cooling passage of the inverter (110) to the inlet of the cooling passage of the rotor.

9. 8. The integrated drive system of claim 7, wherein a second duct connects a boundary of the cooling passage of the stator to a boundary of the cooling passage of the gearbox, the boundary of the cooling passage of the stator and the boundary of the cooling passage of the gearbox being included in the volume.

10. The integrated drive system (100) of any one of claims 5 to 9, wherein the extension (125c) comprises a boundary port of the cooling system, and a third duct (223) connects the boundary portion of the cooling passage of the gearbox (130) to the boundary port of the cooling system.

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