ASSEMBLY COMPRISING AN ELECTRICAL MACHINE AND AN ELECTRONIC HOUSING WITH INTEGRATED POWER CONNECTIONS

Abstract

A motor vehicle traction assembly comprising an electric machine (2) having a male connector (22) with parallel axial studs (26), each connected to one phase of the machine, and a power electronic module fixed to the machine (2) having female connectors, each with a bore for receiving a stud (26), which are tightened by a nut (46) engaged on a thread (28) at the front end of the stud (26), each stud (26) sliding axially in a guide tube (30). Figure 5

Description

Title of the invention: ASSEMBLY COMPRISING AN ELECTRICAL MACHINE AND AN ELECTRONIC HOUSING WITH INTEGRATED POWER CONNECTIONS

[0001] The present invention relates to an assembly comprising an electrical machine receiving an electronic power box having integrated connections which link them, and a motor vehicle equipped with such an assembly used for traction.

[0002] A known type of electric machine used for the traction of a motor vehicle includes an electronic control box for this machine comprising a power inverter which delivers sinusoidal currents to the different phases of the machine, disposed in a cover fixed along the axis of the machine at the end of the casing opposite the output shaft, which closes a volume formed at the end of this casing.

[0003] By placing in the closed volume of the casing an electrical power connector directly linking the inverter to the machine, a very short electrical circuit is obtained between these two parts giving the intermediate conductors a very short length which reduces losses.

[0004] This results in a high compactness of the assembly, better efficiency, reduced mass and limited cost thanks to the short lengths of copper required for the conductors, which is particularly important for traction machines of electric or hybrid motor vehicles.

[0005] It is known to have at the end of the electrical machine a connector comprising three axial pins threaded at their end, connected to the phases of this machine, which each fit into a hole in the inverter to then receive shims of thickness, then a nut ensuring a mechanical link as well as the electrical connection.

[0006] Shims are used to compensate for variations in the axial dimensions of the mass-produced machine and inverter components stacked in this type of assembly. It is therefore necessary to first prepare the assembly, allowing for the determination of a thickness to be compensated for at each stage, then to select the necessary shims with the appropriate thicknesses to compensate for the variations, and finally to proceed with the final assembly.

[0007] This results in an assembly process that is time-consuming and carries risks of errors during measurements, washer selection, and assembly, which can This can lead to high mechanical stresses, and risks of poor electrical connections and premature aging of the contact surfaces.

[0008] In addition, electrical machines generate vibrations, in particular the powertrains of electric vehicles, which can accelerate wear on connectors.

[0009] To avoid axial alignment problems, a type of electrical connector known, presented in particular by document CN-A-116742411, includes a pin held in an insulating housing with a radial adjustment clearance, which fits into a female part which may have an axis offset radially with respect to that of the pin housing.

[0010] The insulating housing has inside a flat conductive annular surface centered on the axis of this housing, connected to an external electrical conductor, receiving under the effect of an axial spring the support of a complementary conductive annular surface of a collar of the pin in order to ensure conduction between these two parts while allowing a lateral offset of this pin which can move radially in the housing.

[0011] When the radially offset female part arrives, the lateral play of the spindle automatically allows its realignment on this female part while maintaining electrical contact and without applying mechanical stress.

[0012] However, this type of known connector does not allow compensation for an axial offset in the case of a connection between two parts each held axially rigidly on their support, which are then clamped together with axial support on each other.

[0013] The present invention aims in particular to avoid these problems of the prior art.

[0014] To this end, it proposes a motor vehicle traction assembly comprising an electric machine having a male connector having parallel axial studs each connected to a phase of this machine, and an electronic power module fixed to this machine, having female connectors each having a hole receiving a stud, which are tightened by a nut engaged on a thread at the front end of the stud, this assembly being remarkable in that each stud slides axially in a guide tube.

[0015] One advantage of this traction assembly is that after positioning the power module on the machine housing, with the studs adjusted in the bores, tightening each nut will, if necessary, depending on the dispersions of the tolerances of the stacked parts, produce an axial adjustment sliding of its stud which is free in the guide tube.

[0016] Automatic axial positioning of the stud is obtained quickly, without prior assembly or individual adjustment, according to the requirement, which does not put any high and abnormal stress in the electrical connection which ensures the quality of the assembly with a reduced cost.

[0017] The vehicle traction assembly according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0018] Advantageously, the stud has a cylindrical front part which is guided in the guide tube.

[0019] Advantageously, the guide tube achieves electrical conduction between the stud and the phase.

[0020] In this case, advantageously the stud comprises a rear part forming an axially elongated flat bar which is pressed into the guide tube by a spring.

[0021] Advantageously the bar has in its length a corrugation receiving in its hollow the spring.

[0022] In particular, the spring may have an arc-shaped form.

[0023] Advantageously, the bar is engaged in a section of the guide tube by forming a rotational block for the stud.

[0024] Advantageously, the male connector includes an insulating plate made by overmolding onto the guide tubes.

[0025] The invention also relates to a method of assembling a traction assembly comprising any one of the preceding characteristics, remarkable in that it carries out a step of placing the power module on the electric machine which simultaneously engages the studs in the female connectors, then a step of tightening the nuts which produces an axial sliding adjustment of these studs.

[0026] The invention further relates to an electric or hybrid motor vehicle, remarkable in that it comprises a traction system including any one of the preceding characteristics.

[0027] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0028] [Fig. 1] presents an electric vehicle powertrain comprising an assembly according to the invention;

[0029] [Fig.2] presents the housing of the electrical machine of this assembly receiving in a closed end volume the male connector;

[0030] [Fig.3] shows the male connector in detail;

[0031] [Fig.4] shows the mounting of the nuts tightening the female connectors of the power module onto the studs; and

[0032] [Fig.5] shows the male connector of the electrical machine with a cut passing through the axis of a stud.

[0033] Figure 1 shows an electrical machine 2 comprising, axially on the side opposite the transmission 4, an internal volume closed by a housing of a power electronic module including an inverter 6 forming a lid that closes this volume by means of an axial movement in a rearward direction during assembly. A powertrain control unit 8 is fixed on top of the electrical machine 2.

[0034] The housing of the inverter 6 has in its lower part a window closed by a cover, allowing access to the connectors linking the three power outputs of this inverter to the phases of the electrical machine.

[0035] Figures 2 and 3 show the internal volume 20 of the housing of the electric machine 2, including a male connector 22 connected to the ends of the windings of the three phases of the electric machine 2 to supply them.

[0036] An insulating plate 24 fixed to the bottom of the volume 20, is made by overmolding on the three phase conductors each comprising an axial guide metal tube 30 turned towards the power module 6, which receives inside a stud 26 having a front end thread 28.

[0037] The insulating plate 24 receives for each phase an axial clamping screw 32 which clamps its conductor onto an end lug of the phase to ensure electrical conduction and mechanical retention of this plate.

[0038] Fig. 4 shows the window 40 of the cover of the inverter 6 arranged opposite the male connector 22 of the electrical machine 2, surrounded by a gasket 42 receiving a cover for closing this window with a seal.

[0039] The inverter 6 has three flat female connectors 44, each having a hole for receiving a stud 26 when it is placed on the electrical machine 2.

[0040] A nut 46 is then screwed onto the thread 28 of each stud 26, which axially clamps the flat connector 44 onto a shoulder of this stud arranged behind it in order to ensure electrical continuity, with an automatic adaptation of the axial positioning of this stud according to the final position of the female connector after the assembly of the inverter 6 on the electrical machine 2.

[0041] The [Fig.5] presents for each phase a sliding metallic conductive axis 50 comprising in front a cylindrical part 52 receiving inside the rear end of the stud 26 screwed into it, which forms by its outer contour a sliding guide in a front circular part of the guide tube 30.

[0042] The cylindrical part of the shaft 52 extends rearward by means of an elongated flat bar 56 comprising a corrugation 58 forming an omega, fitted into a rear rectangular section 54 of the guide tube 30 which blocks the rotation of the stud 26 when tightening its nut 46.

[0043] The undulation 58 of the bar 56 receives in its hollow a spring 60 forming an arc of a circle which bears on a face of the rectangular section 54 to radially press the apex of this undulation on the opposite face, in order to ensure after an axial sliding of the stud 26 an electrical contact between this stud and its guide tube 30.

[0044] During each phase of the final tightening of the nut 46, if necessary, a small free axial adjustment of the stud 26 is obtained depending on the position of the female connector 44, which allows this nut to be tightened without applying axial stress to the electrical connection. The quality of the mechanical retention and electrical continuity is ensured.

Claims

Demands

1. Motor vehicle traction assembly comprising an electric machine (2) having a male connector (22) having parallel axial studs (26) each connected to a phase of this machine, and an electronic power module (6) fixed on this machine (2), having female connectors (44) each having a bore receiving a stud (26), which are tightened by a nut (46) engaged on a thread (28) of the front end of the stud (26), characterized in that each stud (26) slides axially in a guide tube (30).

2. Traction assembly according to claim 1, characterized in that the stud (26) has a cylindrical front part which is guided in the guide tube (30).

3. Traction assembly according to claim 1 or 2, characterized in that the guide tube (30) carries out electrical conduction between the stud (26) and the phase.

4. Traction assembly according to claim 3, characterized in that the stud (26) has a rear part forming an axially elongated flat bar (56) which is pressed into the guide tube (30) by a spring (60).

5. Traction assembly according to claim 4, characterized in that the bar (56) has in its length a corrugation receiving in its hollow the spring (60).

6. Traction assembly according to claim 5, characterized in that the spring (60) has an arc-shaped form.

7. Traction assembly according to claim 4, 5 or 6, characterized in that the bar (56) is engaged in a section of the guide tube (30) by forming a rotational block of the stud (26).

8. Traction assembly according to any one of the preceding claims, characterized in that the male connector (22) comprises an insulating plate (24) made by overmolding on the guide tubes (30).

9. A method for assembling a traction unit according to any one of the preceding claims, characterized in that it performs a step of placing the power module (6) onto the electric machine (2) which simultaneously engages the studs (26) in the

10. female connectors (44), then a tightening step of the nuts (46) which achieves an axial sliding adjustment of these studs (26). Electric or hybrid motor vehicle, characterized in that it comprises a traction assembly according to any one of claims 1 to 8.

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