Housing assembly for driving electric machine of motor vehicle and electric machine having such housing assembly

Abstract

The invention relates to a housing assembly for driving an electric machine of a motor vehicle, comprising: an inner housing part (3) for receiving a stator (43) of the electric machine, having a base (6) integrally formed from a metal material comprising aluminum and an inner jacket part (7), the inner jacket part (7) comprising, on the outer circumferential surface, a channel structure (12) for a cooling fluid; a side part (4) made of a metal material containing aluminum and connected to one end of the inner housing part (3) opposite to the base part (6); an outer housing part (5) having a base (9) and an outer sheath part (10) integrally formed from a plastic material; wherein the outer housing part (5) is mounted on the inner housing part (3) such that the outer sheath part (10) covers the inner sheath part (7), and wherein the channel structure (12) is closed to form a circumferential cooling fluid channel (11). The invention also relates to an electric machine (42) having such a housing assembly.

Description

Technical Field

[0001] The invention relates to a motor housing assembly for driving an electric motor of a motor vehicle, and an electric motor having such a motor housing assembly. Background Art

[0002] From EP 3859951 A1, a motor housing assembly for cooling a motor assembly is known. The motor housing assembly comprises a stator and a rotor. In order to reduce weight and manufacturing costs, the motor housing assembly comprises: an aluminum housing coupled to an outer circumferential surface of the motor assembly and configured to form a first space between the aluminum housing and the motor assembly, the first space comprising an oil flow channel; and a plastic housing coupled to an outer circumferential surface of the aluminum housing and configured to form a second space between the plastic housing and the aluminum housing, the second space comprising a water flow channel.

[0003] From US 2017 / 0302133 A1 an electric pump motor is known which comprises a permanent magnet rotor, a wound stator and a motor housing made of plastic material.

[0004] A housing assembly for a permanent magnet motor is known from US 2006 / 0071567 A1. The housing assembly comprises a ferrous flux ring structure. A plastic housing encapsulates the exterior of the flux ring structure. A bearing is arranged at the closed end of the housing.

[0005] From US 2019 0027993 A1 an electric motor for use in a vehicle actuator is known, which comprises a conductive plastic housing.

[0006] From US Pat. No. 10,680,486 B2, an external rotor motor is known which comprises a rotating shaft, a plastic-encapsulated stator, a plastic-encapsulated body and an external rotor which fits over the plastic-encapsulated stator. Summary of the invention

[0007] The invention is based on the object of proposing a housing assembly for an electric machine for driving a motor vehicle, which housing assembly provides low weight and contributes to energy efficiency and sustainability. A further object is to propose an electric machine with such a housing assembly having high efficiency.

[0008] According to the present invention, a housing assembly for an electric motor for driving a motor vehicle is proposed, comprising: an inner housing portion for receiving a stator of the electric motor, wherein the inner housing portion comprises a base portion and an inner jacket portion integrally formed of a metal material including aluminum, wherein the inner jacket portion comprises a channel structure for a cooling fluid on an outer peripheral surface; a side portion made of a metal material including aluminum, wherein the side portion is connected to an end of the inner housing portion opposite to the base portion; and an outer housing portion, the outer housing portion comprising a base portion and an outer jacket portion integrally formed of a plastic material, wherein the outer housing portion is mounted on the inner housing portion such that the outer jacket portion covers the inner jacket portion, wherein the channel structure is closed so as to form a circumferential cooling fluid channel.

[0009] The proposed housing assembly has the advantage that the inner housing part and the side parts, both formed from metal material, together form a closed mechanical structure, thereby providing high rigidity, wherein, since the outer housing part is made of plastic material, the housing has a very low weight at the same time. Overall, the housing assembly contributes to high energy efficiency and / or cost efficiency.

[0010] In the context of the present disclosure, the term outer shell part relates to the outer jacket part, into which the inner shell part is inserted with its inner jacket part. The outer shell part may also be referred to as a plastic shell part, and the inner shell part may be referred to as a metal shell part. Both the outer shell part and the inner shell part are preferably pot-shaped, in other words, they comprise a base and a jacket part made in one piece. The materials of the inner shell part and the side parts may be the same or different from each other. The metal material of the inner shell part and the side parts may have a higher rigidity than the plastic material of the outer shell part. The plastic material may have a lower density than the metal material.

[0011] The inner housing part can be made of pure aluminum or an aluminum alloy, which can include, for example, more than 90% aluminum by weight, wherein optionally up to 10% by weight of further elements are included. The outer housing part is made of a plastic material, which can be, for example, a fiber-reinforced plastic. Preferred material properties of the plastic material are any type of high-strength plastic or plastic composite.

[0012] According to one embodiment, the base of the inner housing part may have a through hole to receive a first bearing for rotatably supporting the rotor shaft of the electric machine, and the side part connected to the inner housing part may have a side opening to receive a second bearing for rotatably supporting the rotor shaft of the electric machine. Thus, in particular radial forces acting from the first and second bearings to the housing will be well supported, and due to the closed box construction of the metal inner housing part and the metal side part connected thereto, dynamic and static forces are effectively accommodated by the closed force path. The axial forces of the rotor shaft are preferably supported only by the bearing of the base of the inner housing part.

[0013] The base of the inner housing part serves as a bearing support for the rotor shaft. It can also be referred to as an A-shield. In an embodiment in which the base comprises circumferentially distributed ribs on its outer side extending radially outwards from the inner sleeve part, in particular with a reduced axial height, a particularly high stiffness can be achieved.

[0014] In embodiments in which the base and / or the side of the inner housing part comprises a reinforcement ring for receiving the respective first or second bearing, a contribution to particularly high structural properties can be made. The reinforcement ring can be made of a metal material, in particular steel, which has a greater strength than the corresponding metal material of the base and the side.

[0015] The side part is connected to the inner housing part in a rigid manner and serves as a bearing support for the rotor shaft. The side part may also be referred to as a B-shield, a bearing support, a bearing fixing rim or simply a rim. The connection may be achieved by axially mounting the side part to the side of the first housing part, for example by means of circumferentially distributed connecting elements, such as screws.

[0016] In one embodiment, the side portion can be disc-shaped. As an alternative, the side portion can also have an open structure to reduce weight. In particular, the side portion may include an inner ring portion forming an opening of the bearing of the shaft, an outer ring portion or edge connected to the inner housing portion, and a circumferentially distributed web portion extending radially between the inner ring portion and the outer ring portion. In this case, the axial through holes are formed circumferentially between the corresponding web portions, which helps to reduce weight. For example, the number of webs and through holes can be between 3 and 15. The connecting elements for connecting the side portion to the inner housing portion can be arranged circumferentially in the region of the web, but are not limited thereto.

[0017] The web and / or through hole may have the same or different shapes and / or circumferential extensions. In one embodiment, one of the openings may have a larger circumferential extension in order to form a passage for electronic components such as cables and / or connectors. The wall portion surrounding the opening may be used to attach one or more electronic components.

[0018] According to one embodiment, the base of the outer housing part is closed to form an isolated chamber together with the inner housing part. A space, respectively a chamber, can be formed between the closed base of the plastic housing part and the side of the bearing support. The chamber can be configured to accommodate electronic and / or mechanical components of the motor, such as a resolver or an electrical connector.

[0019] The plastic shell part may include a reinforcement ring at one end of the base facing the metal shell part. The reinforcement ring may include an inner circumferential surface centered on the outer circumferential contact surface of the metal shell part, so that the plastic shell part is coaxially arranged on the metal shell part. The coaxial connection section between the inner circumferential surface of the plastic shell part (corresponding reinforcement ring) and the outer contact surface of the metal shell part is preferably an interference fit connection. Other sections between the plastic shell part and the metal shell part, especially the area along the cooling channel, may have a gap. The reinforcement ring is preferably made of a material with higher strength than the plastic material of the main body of the plastic shell part. In particular, a metal ring can be used as a reinforcement ring. The reinforcement ring may include a plurality of circumferentially distributed radial protrusions, which may be configured as a flange connection for connecting to the metal shell part.

[0020] A first seal may be provided between the inner circumferential surface of the reinforcement ring and a circumferential groove of the inner housing part. However, the seal may also be provided to contact the plastic housing part instead of the inner circumferential surface of the reinforcement ring. The seal may be axially shorter than the axial length of the reinforcement ring. Thus, the reinforcement ring is radially supported on the outer contact surface of the metal housing part axially adjacent to the first seal.

[0021] The plastic housing part may have a plurality of circumferentially distributed connecting elements for connection with the base of the metal housing part. The connecting elements may be configured as flange parts into which bolts may be screwed to attach the plastic housing to the metal housing. The dimensions of the plastic and metal housing parts may be such that in the installed condition, at least in one axial section, preferably close to the open end of the plastic housing part, the inner circumferential surface of the plastic housing part is in pre-tensioned contact with the outer circumferential surface of the metal housing part. In other axial sections, in particular along the axial extension of the cooling channel, a radial gap may be present between the inner face of the plastic housing and the outer face of the metal housing. At the axial ends of the metal housing part, an interference fit may again be present between the metal and plastic housing parts.

[0022] In addition, with respect to the above-mentioned purpose, an electric motor for driving a motor vehicle is proposed, comprising: a housing assembly, which can be configured according to any one or more of the above-mentioned embodiments; a stator, which is connected to an inner jacket portion of an inner housing portion in a rotationally fixed manner; and a rotor drivingly connected to a rotor shaft, wherein the rotor shaft is rotatably supported in the inner housing portion and the side portion around a rotor axis.

[0023] The electric machine has the same advantages as described in relation to the housing assembly, so reference is made here to the above description. The electric machine has low weight, high stiffness and thus overall high energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The preferred embodiments of the present invention are described below using the accompanying drawings. Figure 1 The housing assembly according to the present invention is shown in a 3D exploded view; Figure 2 The assembled state is shown in a 3D cross-section. Figure 1 a first housing portion and a side portion of a housing assembly; Figure 3A Shown in side view Figure 1 a side portion of a housing assembly; Figure 3B The axial view shows Figure 1 a side portion of a housing assembly; Figure 3C Based on Figure 3B The 3C-3C cross-sectional view shows Figure 1 a side portion of a housing assembly; Figure 4A Shown in 3D view from the bottom Figure 1 a second housing portion of the housing assembly; Figure 4B Shown in 3D from the open side Figure 1 a second housing portion of the housing assembly; Figure 5A The electric machine according to the invention is shown in longitudinal section and has Figure 1 to the housing assembly shown in 4; Figure 5B The 3D exploded view shows Figure 5A motor; and Figure 6 The modified embodiment is shown Figure 5A Details of the housing assembly. DETAILED DESCRIPTION

[0025] Described below Figures 1 to 4B A housing assembly 2 according to the invention is shown. The housing assembly 2 is for an electric motor for driving a motor vehicle (not shown). The housing assembly 2 comprises an inner housing part 3 for receiving a stator of the electric motor, a side part 4 connectable to the end of the inner housing part 3 and an outer housing part 5 connectable to the inner housing part 3.

[0026] The inner shell part 3 includes a base 6 and a jacket part 7, which are formed integrally by a metal material, particularly a light metal material, such as aluminum or an aluminum alloy. In this regard, the inner shell part 3 may also be referred to as a metal shell part. For example, the metal shell part may be produced by a casting process. The metal material may contain, for example, at least 90% by weight of aluminum, wherein additional elements up to 10% by weight may optionally be included. The side 4 may be connected to the end of the inner shell part 3 opposite to the base 6 by a suitable connecting device 8 (such as a screw), but is not limited thereto. The side 4 is also made of a metal material, particularly a light metal material, such as aluminum or an aluminum alloy. The inner shell part 3 and the side 4 may be made of the same or different metal materials.

[0027] The base 6 of the metal housing forms a bearing support for the rotor shaft of the electric machine and may also be referred to as an A-shield. A through hole 16 is provided in the base 6, through which the rotor shaft of the electric machine can extend, wherein the rotor shaft can be rotatably supported by means of a first bearing 17. A clamping ring 18 may be provided for axially fixing the bearing 17. The base 6 may optionally include circumferentially distributed ribs 21 on its outer side, which extend radially outwards from the inner sleeve portion 31 with a reduced axial height.

[0028] At the opposite end, the side portion 4 serves as a second bearing support for the rotor shaft and may also be referred to as a B shield. The side portion 4 includes an opening 19 to receive a second bearing 20 for rotatably supporting the rotor shaft. The side portion 4 may optionally include a reinforcement ring 47 for receiving the bearing 20. The reinforcement ring 47 may be made of a metal material having greater strength than the metal of the side portion 4.

[0029] Figure 2 The unit described is shown in detail and comprises an inner housing part 3 with an inserted first bearing 17 and a side part 4 connected thereto with an inserted second bearing 20. By means of this housing construction, the forces acting from the first and second bearings 16, 20 to the metal housing and the side part can be effectively accommodated by a closed force path. The force path F is as follows Figure 5A The bearing arrangement may be such that the first bearing 17 is configured as an axially fixed bearing, while the second bearing at 20 may be configured as an axially floating bearing.

[0030] The outer shell part 5 comprises a base part 9 and a jacket part 10 which are integrally formed of a plastic material. In this regard, the outer shell part 5 may also be referred to as a plastic shell part or simply as a plastic shell. The plastic material of the outer shell part may have a lower rigidity than the metal of the inner shell part 3 and / or the side part 4. In addition, the plastic material may have a lower density than the metal material.

[0031] The plastic housing is mounted on the metal housing so that the jacket portion 10 of the plastic housing covers the jacket portion 7 of the metal housing. The jacket portion 7 of the metal housing includes a channel structure 12 on its outer circumferential surface, which has one or more circumferential and / or spirally extending channels formed, for example, by a land portion 13. In the mounted state, the channel structure 12 of the inner jacket portion 7 is closed by the outer jacket portion 10. The outer circumferential surface 14 of the land portion 13 can be in contact with the inner circumferential surface 15 of the outer jacket portion 10, and / or a radial gap can be provided. Therefore, one or more closed cooling fluid channels 11 are formed between the inner jacket portion 7 and the outer jacket portion 10, and a coolant can flow through the cooling fluid channels to cool the motor.

[0032] exist Figures 3A to 3C The side portion 4 shown in detail in the figure comprises an inner ring portion 22 surrounding a cover opening 19 of a bearing of the shaft, an outer ring portion 23 connected to the metal shell portion and circumferentially distributed web portions 24 extending radially between the inner ring portion 22 and the outer ring portion 23. Axial through holes 25 are respectively formed circumferentially between adjacent web portions 24. In the present embodiment, the side portion 4 comprises a plurality of openings 25 having the same shape, and an opening 25' having a larger circumferential extension around the longitudinal axis A2, in particular greater than 30°. The larger opening 25' can be used to attach and / or pass through one or more electronic components, such as cables and connectors 30 (such as for the stator of the motor) Figure 5A shown).

[0033] At the radially outer ring portion 23, the side part 4 comprises circumferentially distributed connecting elements 27 for rigidly attaching the side part 4 to the metal housing. Figure 3A and 3C As shown, the side part 4 can include a circumferentially extending centering portion 31, which interacts with a corresponding centering surface of the inner housing part 3 so that in the installed state, the side part 4 is coaxially connected to the inner housing part 3. The side part 4 can include attachment means 26 on the side of the inner ring part 22 to attach electronic components, in particular a rotary transformer for the motor. The rotary transformer is configured as a rotary electronic transformer for measuring the rotation of the motor.

[0034] Figure 4A and 4B The outer housing part 5 is shown in detail, wherein the base 9 and the jacket part 10 can be seen. The base 9 is closed so that in the installed state, the plastic housing forms a liquid-tight housing for the motor. The plastic housing is formed so that in the installed state (such as Figure 5AAs shown in FIG. 1 , a space, correspondingly a chamber 28, is formed between the closed base 9 of the plastic housing and the side 4 connected to the metal housing. The chamber 28 provides space for an electronic component 29 (eg, a rotary transformer) connected to the side 4.

[0035] The outer housing part 5 comprises a plurality of circumferentially distributed connection elements 32 for connection with the base 6 of the metal housing part. In the present embodiment, the connection elements are configured as circumferentially distributed flange parts, into which bolts 33 can be engaged, for attaching the plastic housing to the base 6 of the metal housing. The base 6 has a corresponding flange part 34, through which the bolts can be passed to engage with the end of the plastic housing.

[0036] The outer housing part 5 also comprises a sealed connection part 35 for a busbar 36 of the electric machine. The busbar 36 can be overmolded into the connection part 35 of the plastic housing. In addition, the outer housing part 5 comprises fluid connectors 37, 37' for the supply, respectively return, of the cooling channel 11 of the cooling fluid. For high rigidity, the plastic housing can optionally comprise longitudinally and / or circumferentially extending ribs 38, 39.

[0037] The first seal ring 40 is provided between the inner circumferential surface of the outer casing portion 5 and the circumferential groove of the inner casing portion 3. The second seal ring 41 is provided between the inner circumferential surface of the outer casing portion 5 and the second circumferential groove of the inner casing portion 3 at the axially opposite ends (eg, Figure 2 and 5A shown).

[0038] Figure 5A and 5B An electric machine 42 for driving a motor vehicle is shown, the electric machine comprising a reference Figure 1 The housing assembly according to the present invention is described in detail in the following. The same and / or corresponding parts are provided with Figure 1 4 , reference is therefore made to the above description regarding the structure and the mode of operation.

[0039] In addition to the housing assembly 2, the electric motor 42 comprises a stator 43, which is connected in a rotationally fixed manner to the jacket portion 7 of the metal housing part, and a rotor 44, which is drivingly connected to a rotor shaft 45. One end of the rotor shaft 45 is rotatably supported in the base 6 of the inner housing part 3, and the opposite end of the rotor shaft 45 is rotatably supported in the side portion 4. The shaft 45 is thus rotatably supported about the rotation axis A2.

[0040] exist Figure 6In the modified embodiment shown, the outer shell part 5 can include a reinforcement ring 46 at its end. The reinforcement ring 46 can be made of a metal material, such as steel. The reinforcement ring 46 includes an inner circumferential surface centered on the outer circumferential contact surface 14' of the metal shell part, so that the two parts (3, 5) are coaxially arranged. In the embodiment with the reinforcement ring 46, the seal 40 can be arranged in the axial extension of the reinforcement ring. In this case, the reinforcement ring 46 is preferably axially longer than the seal, so that the reinforcement ring 46 is radially supported on the outer contact surface 14' of the inner shell part 3, axially adjacent to the sealing ring 40.

[0041] Reference numerals 2 Shell assembly 3 Inner shell part 4 Side 5. Outer shell 6 base (3) 7 Sheath part (3) 8Connection device 9 base (5) 10 Sheath part (5) 11 Cooling channels 12 channel structure 13 Platform part 14, 14' circumferential surface (13) 15 Circumferential surface (9) 16 Through Holes 17 Bearings 18 Clamping ring 19 Cover opening 20 Bearings 21 Rib 22 Inner ring 23 Outer ring 24 belly plate 25 openings (4) 26 Attachment 27 Connecting elements 28 Chamber 29 Electronic components 30 Connectors 31 Sleeve part 32 Connecting elements 33 Bolt 34 Flange section 35 Connection part 36 Busbar 37, 37' fluid connector 38 ribs 39 ribs 40 Sealing ring 41 Sealing ring 42 Motor 43 Stator 44 Rotor 45 rotor shaft 46 Reinforcement ring 47 Reinforcement ring A axis F Force path.

Claims

1. A housing assembly for an electric motor for driving a motor vehicle, comprising: An inner housing part (3) for receiving a stator (43) of an electric machine, wherein the inner housing part (3) comprises a base (6) and an inner jacket part (7) integrally formed of a metal material including aluminum, wherein the inner jacket part (7) comprises a channel structure (12) for a cooling fluid on an outer circumferential surface, a side portion (4) made of a metal material including aluminum, wherein the side portion (4) is connected to an end of the inner housing portion (3) opposite to the base portion (6), an outer shell part (5) comprising a base part (9) and an outer jacket part (10) integrally formed of a plastic material, The outer shell part (5) is mounted on the inner shell part (3) so that the outer jacket part (10) covers the inner jacket part (7), wherein the channel structure (12) is closed, thereby forming a circumferential cooling fluid channel (11).

2. The housing assembly according to claim 1, It is characterized in that The metal material of the inner housing part (3) and the metal material of the side part (4) respectively have greater rigidity and higher density than the plastic material of the outer housing part (5).

3. The housing assembly according to claim 1 or 2, Features The base (6) of the inner housing member (3) has a through hole (16) for receiving a first bearing (17) for rotatably supporting a rotor shaft (45) of the motor (42), and A side portion (4) connected to the inner housing part (3) has an opening (25) to receive a second bearing (20) for rotatably supporting a rotor shaft (45) of the electric machine.

4. The housing assembly according to any one of claims 1 to 3, Features At least one of the base (6) of the inner casing part (3) and the side part (4) connected thereto comprises a reinforcement ring (47) for receiving the respective first or second bearing (17, 20), The reinforcement ring (47) is made of a metal material, in particular steel, which has a greater strength than the metal material of the base (6) and the side (4).

5. The housing assembly according to any one of claims 1 to 4, Features The side portion (4) comprises an inner ring portion (22) forming an opening (25), an outer ring portion (23) connected to the inner shell portion (3), and a circumferentially distributed web portion (24) extending radially between the inner ring portion (22) and the outer ring portion (23).

6. The housing assembly according to any one of claims 1 to 5, Features The side parts (4) are connected to the sides of the inner housing part (3) by circumferentially arranged connecting means (8).

7. The housing assembly according to any one of claims 1 to 6, Features The base (6) of the inner housing part (3) comprises, on its outer side, circumferentially distributed ribs (21) extending radially outwards from the inner sleeve part (31).

8. The housing assembly according to any one of claims 1 to 7, Features The base (9) of the outer shell part (5) is closed, wherein a space (28) is formed between the base (9) of the outer shell part (5) and the sides of the side parts (4).

9. The housing assembly according to any one of claims 1 to 8, Features The outer shell part (5) comprises a reinforcement ring (46) at the end of the base (6) facing the inner shell part (3), wherein the reinforcement ring (46) comprises an inner circumferential surface centered on the circumferential contact surface (14') of the inner shell part (3), so that the outer shell part (5) is coaxially arranged on the inner shell part (3).

10. The housing assembly according to claim 9, Features The reinforcement ring (46) is made of a material having a higher strength than the plastic material of the main body of the outer casing part (5).

11. The housing assembly according to claim 9 or 10, Features The reinforcement ring (46) comprises a plurality of circumferentially distributed radial protrusions, wherein the radial protrusions are configured to be flanged.

12. The housing assembly according to any one of claims 9 to 11, Features A first seal (40) is provided between the inner circumferential surface of the reinforcement ring (46) and the circumferential groove of the inner casing part (3).

13. The housing assembly according to claim 12, Features The first seal (40) is axially shorter than the reinforcement ring (46), so that the reinforcement ring is axially adjacent to the first seal (40) and radially supported on the circumferential contact surface (14') of the inner housing part (3).

14. The housing assembly according to any one of claims 1 to 13, Features The outer housing part (5) has a plurality of circumferentially distributed connecting elements (32) for connecting to the base (6) of the inner housing part (3).

15. Electric motors for driving motor vehicles, including: The housing assembly (2) according to any one of claims 1 to 14, a stator (43) connected in a rotationally fixed manner to the inner jacket part (7) of the inner housing part (3), and A rotor (44) is drivingly connected to a rotor shaft (45), wherein the rotor shaft (45) is rotatably supported about a rotor axis (A2) in the inner housing portion (3) and the side portions (4).

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