WO2016110519A1

WO2016110519A1 - Integrated electric drive system

Info

Publication number: WO2016110519A1
Application number: PCT/EP2016/050156
Authority: WO
Inventors: Jin-kang LI
Original assignee: Continental Automotive Gmbh
Priority date: 2015-01-08
Filing date: 2016-01-07
Publication date: 2016-07-14
Also published as: CN105827060A

Abstract

The present invention provides an integrated electric drive system for a vehicle, comprising: an electric machine (1), comprising an electric machine housing (11), a front end cover, a rear end cover, and a stator (10) and a rotor assembly (14) housed in the electric machine housing (11); a gearbox (2) disposed at an output end of the electric machine (1), the gearbox (2) having a gearbox housing, the gearbox housing comprising a gearbox half-housing (12) close to the electric machine (1), the gearbox half-housing (12) being constructed to be suitable for use as the front end cover of the electric machine (1); and an inverter (3) disposed at another end, opposite the output end, of the electric machine (1), the inverter (3) comprising an inverter housing (13), a power module (31) and an inverter end cover (32), wherein the inverter housing (13) is constructed to be suitable for use as the rear end cover of the electric machine (1); wherein the inverter housing (13) and the gearbox half-housing (12) are mounted on the electric machine housing (11) by means of fastening elements. This electric drive system has a compact structure and lower manufacturing costs.

Description

Title of the invention Integrated electric drive system

Technical field

The present invention relates to the field of motorized vehicles, in particular to an integrated electric drive system for a motorized vehicle.

Background art With the development of automobile technology, in particular with the sustained level of attention that has been paid to electric vehicles (ECV) , hybrid electric vehicles (HEV) and fuel cell electric vehicles (FCEV) in recent years, corresponding research and development are being conducted at an ever deeper level.

An electric drive system for the above types of automobile generally comprises an electric machine, an inverter and a gearbox/transmission. Currently, these three parts (electric machine, inverter and gearbox/transmission) are manufactured separately; the electric machine and gearbox are joined together by means of a fastening element, while the electric machine and inverter are connected together using a multi-phase electric cable. This configuration makes the total volume/dimensions of the gearbox, electric machine and inverter that are

j oined/connected together very large, while the expenditure needed for the internal connection is very high, making the total cost of the electric drive system high. Furthermore, the internal space of an automobile is limited and subject to restrictions, but this existing configuration of electric machine, inverter and gearbox takes up a large amount of space in the automobile, causing difficulties for the overall layout of the vehicle, while the total cost is relatively high. A high-cost electric drive system lacks competitiveness.

Content of the invention

To overcome the above technical problem, the present invention provides an integrated electric drive system for a vehicle, with a compact structure, small overall dimensions and low cost. To this end, the present invention provides an electric drive system for a vehicle, comprising: an electric machine, comprising an electric machine housing, a front end cover, a rear end cover, and a stator assembly and a rotor assembly housed in the electric machine housing; a gearbox disposed at an output end of the electric machine, the gearbox having a gearbox housing, the gearbox housing comprising a gearbox half-housing close to the electric machine, the gearbox half-housing being constructed to be suitable for use as the front end cover of the electric machine; and an inverter disposed at another end, opposite the output end, of the electric machine, the inverter comprising an inverter housing, a power module and an inverter end cover, wherein the inverter housing is constructed to be suitable for use as the rear end cover of the electric machine; wherein the inverter housing and the gearbox half-housing are mounted on the electric machine housing by means of fastening elements.

In the electric drive system, since the gearbox half-housing not only serves as part of the gearbox housing, but is also used as the front end cover of the electric machine, while the inverter housing is used as the rear end cover of the electric machine, the gearbox, electric machine and inverter which are fitted together become structurally compact, with a reduced vol^¬ ume/dimensions and lower costs. According to a preferred solution of the present invention, the stator assembly is provided with an AC input terminal, wherein the AC input terminal is generally a three-phase terminal; the power module is provided with an AC output terminal, wherein the AC output terminal is generally a three-phase terminal, and the AC input terminal and the AC output terminal are configured so that the AC input terminal and the AC output terminal are directly connected together when the electric machine and the inverter have been fitted together. By configuring the AC input terminal and AC output terminal to be connected directly, electric cable is saved, the number of high-voltage connection points is reduced, assembly costs are lowered, and reliability and safety are improved.

According to one solution of the present invention, the AC input terminal on the stator assembly and the AC output terminal on the power module are directly connected together by a threaded connection, welding, soft brazing, hard brazing, riveting or elastic contact. Those skilled in the art should understand that as long as the AC input terminal on the stator assembly and the AC output terminal on the power module can be directly connected together, any suitable connection method is feasible, and included in the scope of the present invention.

In the present invention, the rotor assembly comprises a rotor shaft; advantageously, one end of the rotor shaft is supported by the gearbox half-housing via a first bearing assembly, while another end is supported by the inverter housing via a second bearing assembly. Here, the first bearing assembly and the second bearing assembly may for example be ball bearings or sliding bearings. It should be appreciated that other suitable types of bearing may also be used according to actual needs. According to one solution of the present invention, the first bearing assembly comprises a first bearing seat, and the second bearing assembly comprises a second bearing seat, the first bearing seat being supported at all times on the gearbox half-housing, and the second bearing seat being supported at all times on the inverter housing. Having the first bearing seat supported at all times on the gearbox half-housing has the following technical effects: since the bearing seat of the electric machine is located on the gearbox half-housing, the bearing seat may be processed together with another bearing seat of the gearbox, the relative positional error is very small, transmission precision is high, noise and vibration are low, transmission system components experience little friction, and the service life is long. This structure shares a half-housing, which has good structural rigidity, a low weight and a short axial length. Having the second bearing seat supported at all times on the inverter housing has the following technical effects: an electric machine rear end cover is dispensed with, and the apparatus axial length is reduced; the electric machine rear end cover is integrated into the inverter housing, which has good structural rigidity, thereby reducing electric machine vibration while enhancing the anti-vibration capability of the inverter. According to one solution of the present invention, the fastening elements may comprise a set of fastening bolts which extend through the gearbox half-housing, electric machine housing and inverter housing and fasten these together from one side. According to another solution of the present invention, the fastening elements may comprise two sets of fastening elements, wherein one set is a first set of fastening bolts which extend through the gearbox half-housing and electric machine housing and fasten the two together, while the other set is a second set of fastening bolts which extend through the inverter housing and the electric machine housing and fasten the two together.

The electric drive system configured according to the present invention has the advantages of compact structure, smaller overall dimensions and lower costs, and occupies less space in a vehicle.

Description of the accompanying drawings A fuller understanding of the present invention will be gained, and other features of the present invention will be made obvious, by referring to the detailed description below and the accompanying drawings. The accompanying drawings are merely representative, and are not intended to limit the scope of the claims, wherein:

Fig. 1 is a local exploded perspective view in one direction of an embodiment of the electric drive system according to the present invention, showing a gearbox half-housing, electric motor and inverter housing;

Fig. 2 is a local exploded perspective view in another direction of the electric drive system shown in Fig. 1 ;

Fig. 3 is an exploded perspective view of an embodiment of the inverter according to the present invention; Fig. 4 is an end view of the electric drive system shown in Fig. 1, wherein the gearbox half-housing, electric motor and inverter housing have been fitted together;

Fig. 5 is a sectional view along line A-A in Fig. 4;

Fig. 6 is a sectional view along line B-B in Fig. 4;

Fig. 7 is a local sectional view along line C-C in Fig. 5. Particular embodiments

An electric drive system for a vehicle implemented according to the present invention is described below by way of embodiments with reference to the accompanying drawings. In the following description, many specific details are expounded in order to give those skilled in the art a more comprehensive understanding of the present invention. However, it will be clear to those skilled in the art that implementation of the present invention may omit some of these specific details. Furthermore, it should be appreciated that the present invention is not limited to the specific embodiments presented. On the contrary, consideration may be given to the possibility of using any combination of the features and key elements below to implement the present in- _r

vention, regardless of whether they relate to different em^¬ bodiments. Therefore the aspects, features, embodiments and advantages below serve merely an illustrative purpose, and should not be regarded as key elements or definitions of the claims, unless clearly set out in the claims.

Fig. 1 is a local exploded perspective view in one direction of an embodiment of the integrated electric drive system of the present invention. As Fig. 1 shows, the electric drive system comprises an electric machine 1, a gearbox 2 disposed at an output end of the electric machine, and an inverter 3 disposed at another end of the electric machine; a housing of the gearbox 2 is constructed to be formed of two pieces, i.e. comprises two gearbox half-housings . For the sake of clarity, the figure only shows a gearbox half-housing 12 of the gearbox that is close to the electric motor 1, and an inverter housing 13 of the inverter. In this embodiment, the electric machine 1 comprises an electric machine housing 11, and a stator assembly 10 and a rotor assembly 14 which are housed in a chamber defined by the electric machine housing 11. Advantageously, the gearbox half-housing 12 which is disposed close to the output end of the electric machine 1 is constructed to be suitable for use as a front end cover of the electric machine 1, while the inverter housing 13 is constructed to be suitable for use as a rear end cover of the electric machine 1.

During assembly, a set of fastening bolts 4, e.g. six fastening bolts, may be passed through corresponding openings in the gearbox half-housing 12, corresponding openings in the electric machine housing 11, and corresponding openings in the inverter housing 13 in sequence, to fasten together the gearbox half-housing 12, electric machine housing 11 and inverter housing 13. Alternatively, two sets of fastening bolts may be used, one set of fastening bolts being passed through the gearbox half-housing 12 and electric machine housing 11 in sequence to fasten the two together, and the other set of fastening bolts being passed through the inverter housing 13 and electric machine housing 11 in sequence to fasten the two together. However, it should be appreciated that the above method of fastening is merely exemplary, and other suitable fastening methods are also included in the scope of the present invention. Referring to Figs. 5 - 6, the rotor assembly 14 of the electric machine 1 comprises a rotor shaft 15, one end of the rotor shaft 15 being supported in the gearbox half-housing 12 by means of a bearing assembly 17, the other end being supported in the inverter housing 13 by means of a bearing assembly 18; here, the bearing assemblies 17 and 18 may for example be ball bearings or sliding bearings. Of course, other suitable types of bearing are also feasible. In this embodiment, a bearing seat 17a of the bearing assembly 17 is fixed to the gearbox half-housing 12, e.g. may be formed integrally with the gearbox half-housing 12, while a bearing seat 18a of the bearing assembly 18 is fixed to the inverter housing 13, e.g. may be formed integrally with the inverter housing 13.

This configuration reduces the assembled volume/dimensions when the electric machine 1, gearbox 2 and inverter 3 are fitted together, thereby lowering manufacturing costs.

An inverter is an electronic device with a DC/AC conversion function, which converts DC electricity supplied by a DC power supply to AC electricity by means of a series of internal switch circuits, then supplies this AC electricity to an electronic apparatus operating in an AC environment. In the field of automobiles, an inverter is generally supplied with DC elec^¬ tricity by an in-vehicle battery, and converts this DC elec- tricity to three-phase AC electricity for the in-vehicle electric machine to operate, in order to drive the automobile.

Referring to Fig. 3, the inverter 3 comprises a capacitor module (not shown) and a power module 31, the capacitor module having a DC connection end which is connected electrically to a DC power supply; the power module 31 has multiple switch circuits, a DC input terminal (not shown) and AC output terminals; the AC output terminals are also referred to herein as AC output terminals 301, and the DC input terminal is connected electrically to the DC power supply. The switch circuit converts DC electricity obtained from the DC input terminal to AC electricity, and outputs this AC electricity via the AC output terminals. The inverter housing 13 encapsulates the power module and capacitor module in a chamber formed thereby. The inverter 3 is also provided with an end cover 30, which is mounted, by means of fastening elements such as fastening bolts 5, at that end of the inverter housing 13 which faces away from the electric machine 1.

As Fig. 2 shows, three AC input terminals 101 are provided at that end of the stator assembly 10 of the electric machine 1 which faces towards the inverter 3; from the point of view of the figure, the AC input terminals 101 are disposed on a bottom side of an end of the stator assembly. Correspondingly, as Fig. 3 shows, three AC output terminals 301 are provided at a bottom side of one end of the power module 31 of the inverter 3; the three AC output terminals 301 are configured such that when the inverter 3 and electric machine 1 have been fitted together, the three AC output terminals 301 are in direct contact with the corresponding three AC input terminals 101 (see Fig. 7), and are connected together for example by a threaded connection, welding, soft brazing, hard brazing, riveting or elastic contact, with no need to use an additional connecting wire; this also lowers manufacturing costs.

The term "elastic contact" used here means that in order to realize an electrical connection and reliable conduction of electricity, conductors for conducting electricity must be in reliable contact, wherein one solution is for one of the conductors to have good elasticity, this conductor contacting the other conductor (which other conductor may not have good elasticity) and undergoing a certain amount of deformation, and generating an elastic force through elastic deformation so as to be in reliable contact with the other conductor, thereby re^¬ alizing an electrical connection. Most common household socket/plug systems and automobile insert-connection elements employ such a connection; the essence of this "elastic contact" _

y

connection lies in the use of a material having both conductivity and good elasticity to achieve contact and conduction of electricity, with no need for a third component for fixing. The greatest advantage of using a connection of the "elastic contact" type is that assembly/disassembly is convenient and can be performed multiple times.

In summary, since the electric machine 1 and gearbox 2 share the gearbox half-housing as the front end cover of the electric machine, while the electric machine 1 and inverter 3 share the inverter housing as the rear end cover of the electric machine, the assembled electric drive system comprising the electric machine 1, gearbox 2 and inverter 3 has a significantly reduced total volume (dimensions) , and occupies less floor space, while manufacturing costs are saved. Furthermore, the AC output terminals of the inverter and the AC input terminals of the electric machine are configured to be connected by direct contact once assembly is complete; the use of additional connecting wires during assembly can be avoided, making assembly simple, and lowering assembly costs.

Although the present invention has been disclosed above by way of preferred embodiments, it is by no means limited to this. Various changes and amendments made by any person skilled in the art without departing from the spirit and scope of the present invention shall be included in the scope of protection thereof. Therefore the scope of protection of the present invention shall be the scope defined in the claims.

Claims

Patent claims

1. An integrated electric drive system for a vehicle, comprising: an electric machine (1), comprising an electric machine housing (11), a front end cover, a rear end cover, and a stator assembly (10) and a rotor assembly (14) housed in a chamber defined by the electric machine housing (11);

a gearbox (2) disposed at an output end of the electric machine (1), the gearbox (2) having a gearbox housing, the gearbox housing comprising a gearbox half-housing (12) close to the electric machine (1), the gearbox half-housing (12) being constructed to be suitable for use as the front end cover of the electric machine (1); and

an inverter (3) disposed at another end, opposite the output end, of the electric machine (1), the inverter (3) comprising an inverter housing (13), a power module (31) and an inverter end cover (32), wherein the inverter housing (13) is constructed to be suitable for use as the rear end cover of the electric machine

(I) ;

wherein the inverter housing (13) and the gearbox half-housing (12) are mounted on the electric machine housing

(II) by means of fastening elements.

2. The integrated electric drive system as claimed in claim 1, wherein the stator assembly (10) is provided with an AC input terminal (101), the power module (31) is provided with an AC output terminal (301), and the AC input terminal (101) and the AC output terminal (301) are configured so that the AC input terminal (101) and the AC output terminal (301) are directly connected together when the electric machine (1) and the inverter (3) have been fitted together.

3. The integrated electric drive system as claimed in claim 2, wherein the AC input terminal (101) and the AC output terminal (301) are connected together by a threaded connection, welding, soft brazing, hard brazing, riveting or elastic contact.

4. The integrated electric drive system as claimed in claim 1 or 2, wherein the rotor assembly (14) comprises a rotor shaft (15); one end of the rotor shaft (15) is supported by the gearbox half-housing (12) via a first bearing assembly (17), while another end is supported by the inverter housing (13) via a second bearing assembly (18) .

5. The integrated electric drive system as claimed in claim 4, wherein the first bearing assembly (17) and the second bearing assembly (18) are ball bearings or sliding bearings.

6. The integrated electric drive system as claimed in claim 5, wherein the first bearing assembly (17) comprises a first bearing seat (17a), and the second bearing assembly (18) comprises a second bearing seat (18a), the first bearing seat (17a) being supported at all times on the gearbox half-housing (12), and the second bearing seat (18a) being supported at all times on the inverter housing (13) .

7. The integrated electric drive system as claimed in claim 1 or 2, wherein the fastening elements comprise a set of fastening bolts (4) which extend through the gearbox half-housing (12), electric machine housing (11) and inverter housing (13) and fasten these together from one side.

8. The integrated electric drive system as claimed in claim 1 or 2, wherein the fastening elements comprise a first set of fastening bolts which extend through the gearbox half-housing (12) and the electric machine housing (11) and fasten the two together, and a second set of fastening bolts which extend through the inverter housing (13) and the electric machine housing (11) and fasten the two together.