WO2022068822A1

WO2022068822A1 - Electric drive assembly system and vehicle

Info

Publication number: WO2022068822A1
Application number: PCT/CN2021/121345
Authority: WO
Inventors: Zhenyu Zhao; Wenhui Wang; Long HAN; Jingjing Zhao
Original assignee: Siemens Automotive Epowertrain Systems (Shanghai) Co., Ltd.
Priority date: 2020-09-30
Filing date: 2021-09-28
Publication date: 2022-04-07
Also published as: CN112193044A

Abstract

An electric drive assembly system and a vehicle are disclosed, and the electric drive assembly system includes: a housing including a body, a first end cover and a second end cover, the first end cover and the second end cover are arranged at opposite ends of the body; a reducer assembly located in a first housing space formed by enclosing the body and the first end cover; and a rotor shaft having a rotational axis and a first end near to the first end cover along the rotational axis and a second end opposite to the first end, the rotor shaft rotationally fixed to a rotor of the motor, and the rotor accommodated in a second housing space formed by enclosing the body and the second end cover; wherein the housing is a common housing shared by the motor and the reducer assembly, wherein the electric drive assembly system further includes a first bearing, a second bearing and a third bearing.

Description

ELECTRIC DRIVE ASSEMBLY SYSTEM AND VEHICLE

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Chinese Patent Application No. 202011061297.4 filed on September 30, 2020, the entire disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The embodiments of the present disclosure relate to an electric drive assembly system and a vehicle including the electric drive assembly system.

BACKGROUND

In the current market, the motor, inverter and reducer of electric drive systems are usually manufactured separately. Motor, reducer and inverter are connected to each other via fasteners. Since the housings of the reducer and the motor are separated, the signal connection and cooling water flow between the inverter and the motor require separate connectors and water pipes.

Meanwhile, this electric drive system has a large volume and a large size. The existing integration method of the electric drive system occupies a large space in the overall layout of the vehicle, and therefore brings the following difficulties: the total cost is relatively high, and it lacks market competitiveness.

SUMMARY

In view of the above-mentioned problems and needs, the present invention proposes an electric drive assembly system and a vehicle including the electric drive assembly system, which can solve the above technical problems due to the following technical solutions and has other technical advantages.

According to one aspect of the present invention, an electric drive assembly system is provided, which includes a housing, including a body, a first end cover and a second end cover, the first end cover and the second end cover arranged at opposite ends of the body; a reducer assembly located in a first housing space formed by enclosing the body and the first end cover; and a rotor shaft having a rotational axis and a first end near to the first end cover along the rotational axis and a second end opposite to the first end, the rotor shaft rotationally fixed to a rotor of the motor, and the rotor accommodated in a second housing space formed by enclosing the body and the second end cover. An input pinion of the reducer assembly is integrally formed on the rotor shaft, the input pinion is coaxially arranged with the rotor shaft, and the housing is a common housing shared by the motor and the reducer assembly. The electric drive assembly system further includes a first bearing supporting the rotor shaft at the first end; a second bearing supporting the rotor shaft at the second end; and a third bearing supporting the rotor shaft between the rotor and the input pinion and is installed in the body. A shaft shoulder is formed on the rotor shaft between the third bearing and the rotor, the third bearing abuts against the shaft shoulder, and a radial dimension of the rotor shaft between the shaft shoulder and the first end is smaller than a diameter of the inner ring of the third bearing.

With the above features, the output shaft of the motor and the input shaft of the reducer assembly are formed as an integral shaft, which directly transmits the torque between the motor and the reducer assembly, the bearing span is reduced, and the physical joint is eliminated, thereby avoiding the potential risk of wear and failure in long-term operation.

The common housing of the motor and the gear input shaft can reduce one housing part, and reduce a set of die-casting abrasive tools correspondingly, and in turn the weight and overall size of the electric drive assembly system can be reduced, which is more conducive to its spatial arrangement in the vehicle and makes it more competitive in the market. For example, the length of the electric drive assembly system along the rotational axis can be reduced by 15-20mm.

In addition, the radial dimension of the rotor shaft from the shaft shoulder to the first end is designed to be smaller than the diameter of the inner ring of the third bearing, which is convenient for assembly and disassembly.

In some examples, the first bearing is installed in the first end cover, and the second bearing is installed in the second end cover.

With the above features, the two bearings can be respectively installed in the bearing mounting holes integrally formed in the first end cover and the second end cover, compared with separately providing a bearing seat with a bearing hole and then connecting the bearing seat to the housing, it is easier to simplify the structure, and is more conducive to ensuring the machining accuracy of the bearing hole.

In some examples, the rotor shaft is further provided with a snap ring, and the snap ring abuts against a side of the third bearing opposite to the shaft shoulder.

With the above features, the provision of a snap ring on the rotor shaft can facilitate fixing the axial position of the third bearing.

In some examples, a lip-type seal extending in the circumferential direction is provided between the rotor shaft and the body and adjacent to the third bearing, the lip-type seal is arranged on other side of the third bearing opposite to the snap ring.

In some examples, a shaft hole extending along the rotational axis in the rotor shaft is provided at the first end.

In some examples, the shaft hole extends beyond the shaft shoulder along the axis of rotation.

By providing the shaft hole, the weight of the rotor shaft can be reduced while ensuring the overall strength.

In some examples, at least one of the first bearing, the second bearing, and the third bearing is a deep groove ball bearing.

With the above features, the use of deep groove ball bearings can reduce the cost while ensuring the reliability of the support.

In some examples, the reducer assembly is a reducer layout of two-stage helical gear parallel shaft.

In some examples, the electric drive assembly system is provided with a differential that is provided in the first housing space and is coupled to the reducer layout.

In some examples, the reducer layout and differential are provided with deep groove ball bearings.

In some examples, the electric drive assembly system further includes an inverter housing, and the inverter housing is fixed to the motor housing.

According to another aspect of the present invention, a vehicle is provided, including an electric drive assembly system as described above.

In summary, in the electric drive assembly system proposed by the present invention, the output shaft of the motor and the input shaft of the reducer assembly are formed as an integral shaft, which directly transmits the torque between the motor and the reducer assembly, the bearing span is reduced, and the physical joint is eliminated. The common housing of the motor and the gear input shaft can reduce one housing part, and reduce a set of die-casting abrasive tools correspondingly. In addition, only three bearings are needed to support the rotor shaft, which can reduce the weight and overall size of the electric drive assembly system, which is more conducive to its spatial arrangement in the vehicle and makes it more competitive in the market. Since the vehicle proposed by the present invention has the above-mentioned electric drive assembly system, it also has the same advantages and benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings of the embodiments of the present invention will be briefly introduced below. Among them, the drawings are only used to show some embodiments of the present invention, instead of limiting all the embodiments thereof to these.

Fig. 1 is a front view of an electric drive assembly system according to an exemplary embodiment of the present invention;

Fig. 2 is a cross-sectional view of an electric drive assembly system according to an exemplary embodiment of the present invention.

Reference numerals

1 Housing

11 Body

12 First end cover

13 Second end cover

2 Rotor shaft

21 First end

22 Second end

3 Snap ring

4 First bearing

5 Second bearing

6 Third bearing

7 Lip-type seal

101 Input pinion

102 Intermediate first gear

103 Intermediate second gear

104 Intermediate shaft

20 Differential

100 Motor

110 Rotor

120 Stator

200 Reducer assembly

300 Inverter

301 Inverter housing

40 First housing space

50 Second housing space

A Rotational axis

DETAILED DESCRIPTION

In order to make the objectives and advantages of the technical solutions of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely in conjunction with the accompanying drawings of specific embodiments of the present disclosure. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are just a part but not all of the embodiments of the present disclosure. Based on the described embodiments herein, those skilled in the art can obtain other embodiment (s) , without any inventive work, which should be within the scope of the present disclosure.

Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings commonly understood by those with ordinary skills in the art to which the present disclosure belongs. The terms “first, ” “second, ” etc., which are used in the description and the claims of the present disclosure, are not intended to indicate any sequence, amount or importance, but distinguish various components. Similarly, similar terms such as "a" or "an" do not necessarily indicate quantitative restrictions. The terms "include" or "comprise" and other similar words mean that the element or item appearing before the word encompasses the element or item listed after the word and its equivalents, but does not preclude other elements or items. Similar terms such as "connect" or "connected with" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "up" , "down" , "left" , "right" , etc. are only used to indicate the relative position relationship, and when the absolute position of the described object changes, the relative position relationship may also change accordingly.

Electrification has become one of the important development directions of the automobile industry. As the power system of electric vehicles, the electric drive assembly system is focused on its integration, light weight, and reliability.

The electric drive assembly system is a highly integrated electric drive system, which is usually composed of a permanent magnet synchronous motor, an inverter and a reducer assembly. In the current market, the motor, inverter, and reducer assembly of the electric drive system are usually manufactured separately, the motor, reducer assembly, and inverter are connected to each other via fasteners. This separate arrangement makes the electric drive assembly system larger in volume and size, heavier in weight, and occupies a lot of space in the overall layout of the vehicle.

The output shaft of the motor and the input shaft of the reducer assembly are connected by a mechanical joint, which may cause wear and failure in long-term operation.

Based on the above problems, the present invention proposes an electric drive assembly system and a vehicle including the electric drive assembly system, especially an electric vehicle.

Fig. 1 is a front view of an electric drive assembly system according to an exemplary embodiment of the present invention. Fig. 2 is a cross-sectional view of an electric drive assembly system according to an exemplary embodiment of the present invention.

As shown in Fig. 1, the electric drive assembly system may include a motor 100, a reducer assembly 200 and an inverter 300. The inverter 300 converts direct current (for example a battery, a storage battery) into a constant frequency and constant voltage or a frequency and voltage regulation alternating current to be input to the motor 100. The motor 100 is, for example, a permanent magnet synchronous motor or an AC asynchronous motor. The motor 100 is connected to the reducer assembly 200 in transmission, so that the torque of the motor 100 is decelerated by the reducer assembly 200 and output.

The motor 100 may include a rotor 110 and a stator 120. The arrangement of the rotor 110 and the stator 120 is a common method in the art, which will not be described in detail in the present disclosure.

Fig. 2 shows a cross-sectional view of an electric drive assembly system according to an exemplary embodiment of the present invention, and Fig. 2 further details the structure diagram of the electric drive assembly system. As shown in Fig. 2, the electric drive assembly system further includes: a housing 1, a rotor shaft 2, a first bearing 4, a second bearing 5 and a third bearing 6.

The housing 1 includes a body 11, a first end cover 12 and a second end cover 13. The first end cover 12 and the second end cover 13 are disposed at opposite ends of the body 11. The first end cover 12 and the second end cover 13 may be installed to the body 11 by fasteners, such as bolts. Optionally, the first end cover 12 and the second end cover 13 may also be welded to the body 11 after assembly.

A part of the body 11 and the first end cover 12 are encompassed to form a first housing space 40, and another part of the body 11 and the second end cover are encompassed to form a second housing space 50. Specifically, a part of the first housing space 40 is provided by the body 11 and the other part is provided by the first end cover 12. The second housing space 50 is defined by a part of the body 11, and the second end cover 13 closes the second housing space 50. The reducer assembly 200 is accommodated in the first housing space 40, and the rotor 110 of the motor 100 is accommodated in the second housing space 50. In addition, the stator 120 of the motor 100 may also be accommodated in the second housing space 50.

Therefore, compared with the manner that the motor and the reducer are arranged separately, the housing 1 and the first end cover 12 provided by the present invention can save a housing part, and therefore reduce the die-casting mold for processing the housing part. In addition, the arrangement of the shared housing of the motor and the reducer can also obtain a more compact and light-weight electric drive assembly arrangement, which can actually reduce the length (in the direction of the rotational axis A of the rotor shaft 2) by 15-20mm.

The rotor shaft 2 is rotationally fixed to the rotor 110 of the motor 100. The rotor shaft 2 has a rotational axis A, and has a first end 21 near to the first end cover 12 along the rotational axis A and a second end 22 opposite to the first end 21. The rotor shaft 2 is rotationally fixed to the rotor 110 of the motor 100.

It should be noted that “rotationally fixed” mentioned herein refers to that two components are connected in a manner that they can rotate together, and their mutual movement in the direction of rotation (for example, the circumferential direction) is restricted so as to be able to rotate together. "Rotationally fixed" does not limit the displacement along the direction of the rotational axis A, therefore, the two components that are rotationally fixed together can be relatively displaced along the direction of the rotational axis A. If the displacement in the direction of the rotational axis A is also fixed, it can be considered that the two components are completely fixedly connected.

The input pinion 101 of the reducer assembly 200 is integrally formed on the rotor shaft 2, and the input pinion 101 is coaxially arranged with the rotor shaft 2. For example, the input pinion 101 can be integrally forged with the rotor shaft 2 and the tooth surface is machined. The present disclosure is not limited to this, and those skilled in the art can also use other common integral molding methods.

Compared with separately setting the motor output shaft and input pinion shaft and connecting them through a mechanical joint, the integrally formed shaft of the present invention directly transmits the torque between the motor and the reducer assembly, reduces the bearing span, eliminates physical joints, and avoids the potential risks of wear and failure in long-term operation.

Further, the first end 21 of the rotor shaft 2 is supported by the first end cover 12, the second end 22 of the rotor shaft 2 is supported by the second end cover 13, and the middle part of the rotor shaft 2 between the first end 21 and the second end 22 is supported by the body 11. The middle part is located at the edge of the first housing space 40 adjacent to the second housing space 50. Specifically, the support of the rotor shaft 2 is realized by the first bearing 4, the second bearing 5 and the third bearing 6 respectively, which will be described in detail below.

In this embodiment, the housing 1 is a common housing shared by the motor 100 and the reducer assembly 200.

In this embodiment, the first bearing 4 supports the rotor shaft 2 at the first end 21, and the second bearing 5 supports the rotor shaft 2 at the second end 22. The third bearing 6 supports the rotor shaft 2 between the rotor 110 and the input pinion 101. Specifically, the third bearing 6 supports the aforementioned intermediate part of the rotor shaft 2.

Specifically, the first bearing 4 is installed in the first end cover 12, and the second bearing 5 is installed in the second end cover 13. The first end cover 12 and the second end cover 13 can be integrated to form a bearing mounting hole for mounting the bearing. Compared with separately providing a bearing seat with a bearing hole and then connecting the bearing seat to the housing, it is easier to simplify the structure, and is more conducive to ensuring the machining accuracy of the bearing hole.

In this embodiment, the rotor shaft 2 forms a shaft shoulder between the third bearing 6 and the rotor 110, and the third bearing abuts against the shaft shoulder, a radial dimension of the rotor shaft 2 from the shaft shoulder to the first end 21 is smaller than the diameter of the inner ring of the third bearing 6.

It should be noted that, in this description, “shaft shoulder" refers to the part where the cross-sectional dimension of the stepped shaft changes. The shaft shoulder has a larger diameter and a smaller diameter at the part where the cross-section changes, which are called big diameter and small diameter, respectively. In this embodiment, the small diameter of the shaft shoulder is near to the first housing space 40, and the big diameter of the shaft shoulder is near to the second housing space 50.

In this embodiment, the rotor shaft 2 may also be provided with a snap ring 3, and the snap ring 3 abuts against a side of the third bearing 6 opposite to the shaft shoulder. Specifically, the third bearing 6 is installed in the bearing mounting hole of the body 11, and one side of the third bearing 6 abuts against the shaft shoulder, and the other side is abutted by the snap ring 3, thereby installing the third bearing 6 in place.

In addition, the rotor shaft 2 may be provided with a mounting groove for accommodating the snap ring 3 to fix the position of the snap ring 3.

Exemplarily, a lip-type seal 9 extending in the circumferential direction is provided between the rotor shaft 2 and the body and adjacent to the third bearing 6, and the lip-type seal 9 is a bidirectional seal. The lip-type seal 9 is arranged on other side of the third bearing 6 opposite to the snap ring 3.

Exemplarily, a shaft hole extending along the rotational axis A in the rotor shaft 2 is provided at the first end 21. Optionally, the shaft hole extends along the rotational axis A beyond the shaft shoulder. By providing the shaft hole, the overall weight of the rotor shaft 2 can be reduced while ensuring the overall strength.

Exemplarily, at least one of the first bearing 4, the second bearing 5, and the third bearing 6 is a deep groove ball bearing. In this embodiment, the first bearing 4, the second bearing 5 and the third bearing 6 are all deep groove ball bearings.

Exemplarily, the reducer assembly 200 can be a reducer layout of two-stage helical gear parallel shaft. The electric drive assembly system is provided with a differential 20 provided in the first housing space 40 and is coupled to the reducer layout. Fig. 2 shows a reducer layout of two-stage helical gear parallel shaft in an exemplary and non-limiting manner.

The reducer assembly 200 may include an input pinion 101, an intermediate first gear 102 and an intermediate second gear 103. As mentioned above, the input pinion 101 is integrally formed with the rotor shaft 2. The intermediate first gear 102 and the intermediate second gear 103 are sequentially arranged on the intermediate shaft 104. The intermediate shaft 104 is arranged in parallel with the rotor shaft 2, and the intermediate shaft 104 may be a hollow shaft. The sizes of the input pinion 101, the intermediate first gear 102, and the intermediate second gear 103 can be selected according to actual requirements. The first intermediate gear 102 is drivingly meshed with the input pinion 101, and the second intermediate gear 103 may be fixed to the differential 20 by bolts. This exemplarily realizes the reducer layout of two-stage helical gear parallel shaft from the rotor shaft 2 to the differential 20.

Optionally, the reducer layout and the differential 20 are provided with deep groove ball bearings. For example, the two ends of the intermediate shaft 104 and the two ends of the differential 20 can be supported by deep groove ball bearings, respectively. Half of the deep groove ball bearings are installed in the first end cover 12, and the other half of the deep groove ball bearings are installed in the body 11.

Optionally, the electric drive assembly system may also include a cooling and heat exchange system. The cooling and heat exchange system is, for example, a circulating water cooling system, which is arranged in the second housing space 50, and cools the stator of the motor 100 by means of water cooling. The cooling and heat exchange system may further include heat sinks for enhancing heat dissipation, which may be integrally formed with the second end cover 13 or fixedly connected to the second end cover 13.

In addition, the electric drive assembly system may further include an inverter housing 301, and the inverter housing 301 is fixed to the housing 1. In summary, the connection and arrangement between the motor 100, the reducer assembly 200 and the inverter 300 are thus formed.

According to another aspect of the present invention, a vehicle is provided, which includes the electric drive assembly system as described above. In particular, the vehicle may be an electric vehicle.

In summary, in the electric drive assembly system proposed by the present invention, the output shaft of the motor and the input shaft of the reducer assembly are formed as an integral shaft, which directly transmits the torque between the motor and the reducer assembly, the bearing span is reduced, and the physical joint is eliminated. The common housing of the motor and the gear input shaft can reduce one housing part, and reduce one set of die-casting abrasive tools correspondingly. In addition, only three bearings are needed to support the rotor shaft, which can reduce the weight and overall size of the electric drive assembly system, which is more conducive to its spatial arrangement in the vehicle and makes it more competitive in the market. Since the vehicle proposed by the present invention has the above-mentioned electric drive assembly system, it also has the same advantages and benefits.

The above are merely specific implementation manners of the present disclosure, but the protection scope of the embodiments of the present disclosure is not limited thereto. Any changes, alternatives and combinations that a person skilled in the art could readily conceive of within the technical scope disclosed in the embodiments of the present disclosure or under the ideas disclosed in the embodiments of the present disclosure shall be included in the protection scope of the embodiments of the present disclosure. Therefore, the scope of the disclosure is determined by the appended claims.

Claims

An electric drive assembly system comprising:

a housing comprising a body, a first end cover and a second end cover, the first end cover and the second end cover provided at opposite ends of the body;

a reducer assembly located in a first housing space formed by enclosing the body and the first end cover; and

a rotor shaft having a rotational axis and having a first end near to the first end cover along the rotational axis and a second end opposite to the first end, said rotor shaft rotationally fixed to a rotor of the motor, and said rotor received in a second housing space formed by enclosing the body and the second end cover;

wherein an input pinion of the reducer assembly is integrally formed on the rotor shaft, and the input pinion is coaxially arranged with the rotor shaft,

wherein the housing is a common housing shared by the motor and the reducer assembly,

wherein the electric drive assembly system further comprises:

a first bearing supporting the rotor shaft at the first end;

a second bearing supporting the rotor shaft at the second end; and

a third bearing supporting the rotor shaft between the rotor and the input pinion and installed in the body,

wherein a shaft shoulder is formed on the rotor shaft between the third bearing and the rotor, the third bearing abuts against the shaft shoulder, and a radial dimension of the rotor shaft between the shaft shoulder and the first end is smaller than a diameter of the inner ring of the third bearing.
The electric drive assembly system according to claim 1, wherein the first bearing is installed in the first end cover, and the second bearing is installed in the second end cover.
The electric drive assembly system according to claim 1, wherein the rotor shaft is further provided with a snap ring, which abuts against a side of the third bearing opposite to the shaft shoulder.
The electric drive assembly system according to claim 3, wherein a lip-type seal extending in the circumferential direction is provided between the rotor shaft and the body and adjacent to the third bearing, and the lip-type seal is arranged on other side of the third bearing opposite to the snap ring.
The electric drive assembly system according to claim 1, wherein a shaft hole extending along the rotational axis in the rotor shaft is provided at the first end.
The electric drive assembly system according to claim 5, wherein the shaft hole extends beyond the shaft shoulder along the rotational axis.
The electric drive assembly system according to claim 1, wherein at least one of the first bearing, the second bearing, and the third bearing is a deep groove ball bearing.
The electric drive assembly system according to claim 1, wherein the reducer assembly is a reducer layout of two-stage helical gear parallel shaft.
The electric drive assembly system according to claim 8, wherein, the electric drive assembly system is provided with a differential, which is provided in the first housing space and is coupled to the reducer layout.
The electric drive assembly system according to claim 9, wherein the reducer layout and differential are provided with deep groove ball bearings.
The electric drive assembly system according to claim 1, further comprising an inverter housing fixed to the motor housing.
A vehicle comprising the electric drive assembly system according to any one of claims 1 to 11.