ASSEMBLY WITH ELECTRICAL MACHINE INCLUDING A CONNECTOR IN A CLOSED COVER

Abstract

Assembly with an electrical machine comprising a machine housing, a casing closing a volume of the housing by an axial assembly movement, and within the closed volume connections, each having a pin (14) facing a forward axial direction (AV), which inserts into a female part comprising axially elongated conduction tabs (36) bearing against this pin (14) to ensure electrical contact, each connection having an axially sliding ring (40) surrounding the tabs (36), which, during a final stroke of the assembly movement, is pushed by a surface (46) connected to the pins (14), tightening the tabs (36) on its inner pin (14). Figure 2

Description

Title of the invention: Assembly with electrical machine comprising a connector in a closed volume of the casing

[0001] The present invention relates to an assembly with an electric machine comprising a connector disposed in a volume of the casing which is closed by a housing carrying one of the parts of the connector, as well as a motor vehicle equipped with such an assembly comprising an electric traction machine.

[0002] A known type of electrical machine includes an electronic control unit for this machine comprising a power inverter which delivers sinusoidal currents to the different phases of the machine, forming a cover fixed along the axis of the machine at the end of its casing opposite the output shaft, which closes a volume of this casing,

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

[0004] This results in a high compactness of the assembly, better efficiency, reduced mass, and a cost limited by 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 provide, within the enclosed space between the housing and the casing, a connector comprising axial pins fixed to one element, which fit into female parts of another element during the final assembly stroke of this casing. This type of axial mounting of the casing, which simultaneously makes the connections, allows for rapid assembly without requiring special handling for each phase, such as tightening screws to establish these connections.

[0006] In addition, the connector remains in the volume closed by the electronic housing forming a cover, which ensures protection of the protected contacts inside, and gives a compact assembly which is axially short.

[0007] However, with the mass production of each sub-assembly, the electrical machine comprising one part of the connector and the electronic housing the other part, it is possible to obtain, with manufacturing variations, for each connection during assembly small radial offsets between the axes of a spindle and its female part.

[0008] For significant offsets, problems of high mechanical stress on the components are then obtained, with high pressure on one side of the spindle and low on the other, and electrical contacts that are poorly ensured over the complete contour of the spindles which can generate electrical conduction defects and premature aging of the contact surfaces.

[0009] In addition, electrical machines generate vibrations, in particular the powertrains of electric vehicles, which can accelerate wear on connectors.

[0010] To avoid these problems, a type of electrical connector known, presented in particular by document CN-A-116742411, has a pin held in an insulating housing having an assembly axis, with a radial adjustment float, which fits into a female part which may have an axis offset radially with respect to that of the housing.

[0011] 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.

[0012] When the radially offset female part arrives, the lateral float of the spindle automatically allows its realignment on this female part, while maintaining electrical contact and without adding mechanical constraints.

[0013] However, in addition to the first mobile electrical contact between the female part and the floating pin, a second mobile contact arranged in series is obtained, formed by the two supporting annular surfaces, which increases electrical resistances, the risks of wear in particular with vibrations, and which requires suitable materials with higher costs in order to optimize conduction and guarantee its durability over time.

[0014] In addition, the collar with the annular contact surfaces forms a housing with larger dimensions, adding radial bulk and length to the connector which can be troublesome, particularly for compact assemblies used in motor vehicles.

[0015] The present invention is intended in particular to avoid these problems of the prior art.

[0016] To this end, it proposes an assembly with an electrical machine comprising a machine housing, a casing closing a volume of the housing by an axial assembly movement, and in the closed volume connections each having a pin facing a forward axial direction, which inserts into a female part comprising axially elongated conduction tabs bearing on this pin to ensure electrical contact, this assembly being remarkable in that each connection has an axially sliding ring, surrounding the tabs, which during a final stroke of the assembly movement is pushed by a surface linked to the pins by tightening the tabs on its inner pin.

[0017] One advantage of this assembly is that during the assembly of the housing enclosing the connections inside, without having access, a preliminary insertion of each pin into the tabs of the female part is made possible by the flexibility of these tabs, giving little stress on the pin, then at the end of the insertion, axial pressure is applied to the ring, allowing these tabs to be tightened, giving strong contact pressure around the pin which ensures the electrical connection.

[0018] First, ease of assembly is obtained with few mechanical constraints during this assembly, and second, an electrical connection is ensured by a high pressure between the conductive parts, guaranteeing electrical conduction over time despite vibrations.

[0019] The assembly with electric machine according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0020] Advantageously, each tab comprises a straight axial portion and then an end boss for contact with the pin.

[0021] In this case, advantageously the front edge of the inner contour of each ring is, at the beginning of the final stroke, above the bosses of the tabs before their straight part.

[0022] Advantageously, each ring is guided in a cylindrical part of an insulating support holding the female parts.

[0023] In addition, each ring may have on its outer contour an axially elongated tenon which is fitted into an axial groove in the cylindrical part to prevent its rotation.

[0024] Advantageously, each female part comprises a collar including in the same piece the axial tabs, which has a transverse face fixed on a conductor formed by a sheet.

[0025] The conductors can be held together by overmolding in an insulating support.

[0026] Advantageously, the housing contains a power inverter for the electrical machine.

[0027] The invention also relates to a method for assembling the casing of an assembly with an electrical machine comprising any one of the preceding characteristics, remarkable in that it performs a final stroke stage of the movement assembly of this case by causing the rings to slide in this final stroke.

[0028] The invention further relates to an electric or hybrid motor vehicle comprising an electric traction machine which is part of an assembly comprising any one of the preceding characteristics.

[0029] 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:

[0030] [Fig-1] shows the assembly of an inverter housing closing a casing of an assembly with an electrical machine according to the invention, comprising the assembly of a three-phase connector;

[0031] [Fig.2] shows the two parts of the connector;

[0032] [Fig.3] shows the female part of the connector;

[0033] [Fig.4] shows in detail the conductive sheet of one phase of this female part;

[0034] [Fig. 5] presents an axial cross-sectional view of the two parts of a connection; and

[0035] [Fig.6] shows the beginning of the final run of final setup of this connection.

[0036] The [Fig. 1] presents an electrical machine comprising a machine housing 2 comprising axially on the side opposite the transmission shaft, an internal volume 4 which is closed by an inverter housing 8 forming a cover bearing on a joint plane 6 to achieve a seal of this volume.

[0037] The transverse face at the bottom of the closed volume 4 has a circular plate 10 tightened on its contour by screws, comprising three cylindrical pins 14 turned towards a front axial direction AV, which are each connected to the winding of a phase of the machine's stator.

[0038] At the end of the assembly movement of the inverter 8, each pin 14 retracts into an aligned female part connected to this inverter, automatically ensuring an electrical connection, without the possibility of intervention because the inverter is in the process of closing the internal volume 4. This results in a compact connection system, comprising, along the axial direction, the minimum space required for the pin surrounded by the female part. Furthermore, the assembly time is rapid, as the positioning of the inverter 8 automatically establishes the phase connections, without any additional intervention.

[0039] However, during the preparation of the sub-assemblies, the electrical machine 2 and the inverter 8, the positioning of the pins 14 on the machine and of the female parts on the inverter may have small lateral offsets compared to the theoretical positions, which give misalignments during the final assembly.

[0040] Figures 2, 3, 4 and 5 show on the circular plate 10 each pin of a phase 14 held in a hole in the plate with an intermediate insulator 16, its front end being rounded to facilitate insertion into the female part, its rear end being connected to the winding of its phase.

[0041] A female part support 20 elongated in a circular direction, formed by a molding of an insulating plastic material, has at each end a tab having a hole 22 for fixing this support on an inner transverse face of the inverter 8.

[0042] The support 20 includes for each connection a conductive sheet 24 integrated into this support by an overmolding of the plastic material, comprising a flat face perpendicular to the axis, presenting radially towards the outside of the machine a perpendicular fold 26 having a hole receiving a screw for tightening a lug of a conductor coming out of the inverter 8, to supply a phase of the electric machine 2.

[0043] Each conductive sheet 24 carries an added collar 30 formed in a sheet, comprising a transverse face 32 fixed by crimps 34 on the front side of the flat face of this sheet, and axial tabs 36 turned towards the rear, passing through a hole in the flat face, together forming a generally cylindrical shape surrounding the spindle 14.

[0044] Each tab 36 has after a straight axial part, a rear end having radial elasticity, comprising a boss turned towards the axis 38 which ends with a rise to form an entry chamfer facilitating the introduction of the domed end of the pin 14 into the set of tabs by spreading them apart.

[0045] The tabs 36 have significant radial elasticity which allows this introduction without high mechanical effort, but with a contact pressure of each boss 38 on the spindle 14 which is insufficient to guarantee reliability of the contact over time, in particular with the vibrations and heating generated by the operation of the electrical machine 2.

[0046] On each phase, a generally cylindrical sliding ring 40 surrounding the tabs 36, fitted into a cylindrical portion 50 of the support 20, has on its outer contour two opposing axial tenons 42 which are engaged in elongated grooves in this cylindrical portion to ensure axial guidance of the ring. In a rear position of each ring 40, the inner contour of its front end 44 lies in the recess left outside the bosses 38 of the tabs 36.

[0047] Figure 6 shows the beginning of a final axial travel C of the inverter 8 on the electrical machine 2, comprising a transverse surface 46 of this inverter behind the pins 14 which comes into contact with the rear edge of each ring 40, and pushes this ring forward for the final stroke, until the inverter is fully in place.

[0048] The inner contour 44 at the front end of each ring 40 has a diameter slightly smaller than the outer contour of all the straight parts of the tabs 36. At the beginning of the final stroke C, a pressure P is obtained from the front inner contour of the ring 44 on the straight parts of the tabs 36, which forces the tabs during this stroke to tighten on the spindle 14 by applying a hold which prevents any vibration, and a significant pressure from their bosses 38 on this spindle which ensures the reliability of the electrical contact.

[0049] In particular, if the pin 14 is misaligned with the axis of the female part, the additional pressure exerted by the sliding of the ring 40 on all the tabs 36 ensures that the tabs furthest from the pin axis bear on the pin with their bosses 38 to obtain sufficient electrical conduction. All the tabs 36 contribute to the passage of current, with mechanical support preventing vibrations, thus ensuring the reliability of the connector.

[0050] The ring 40 surrounding the tabs 36 of the connector according to the invention does not add any additional axial and radial dimension to this connector, which allows the overall dimensions to remain unchanged.

Claims

Demands

1. Assembly with electric machine comprising a machine housing (2), a housing (8) closing a volume of the housing (4) by an axial assembly movement, and in the closed volume (4) connections each having a pin (14) turned towards a forward axial direction (AV), which fits into a female part comprising axially elongated conduction tabs (36) bearing on this pin (14) to ensure electrical contact, characterized in that each connection has an axially sliding ring (40), surrounding the tabs (36), which during a final stroke of the assembly movement (C) is pushed by a surface (46) linked to the pins (14) tightening the tabs (36) on its inner pin (14).

2. Assembly with electric machine according to claim 1, characterized in that each tab (36) has a straight axial part and then an end boss (38) for contact with the spindle (14).

3. Assembly with electric machine according to claim 2, characterized in that a front edge of the inner contour (44) of each ring (40) is, at the beginning of the final stroke (C), above the bosses (38) of the tabs (36) before their straight part.

4. Assembly with electrical machine according to any one of the preceding claims, characterized in that each ring (40) is guided in a cylindrical part (50) of an insulating support (20) holding the female parts.

5. Assembly with electric machine according to claim 4, characterized in that each ring (40) has on its outer contour an axially elongated tenon (42) which is fitted in an axial groove of the cylindrical part (50) to prevent its rotation.

6. Assembly with electrical machine according to any one of the preceding claims, characterized in that each female part comprises a collar (30) including in the same piece the axial tabs (36), which has a transverse face (32) fixed on a conductor formed by a sheet (24).

7. Assembly with electrical machine according to claim 6, characterized in that the assembly of conductors (24) is held by overmolding in an insulating support (20).

8. Assembly with electric machine according to any one of the preceding claims, characterized in that the housing (8) contains a power inverter for the electric machine.

9. Method of assembling the housing (8) of an assembly with an electric machine according to any one of the preceding claims, characterized in that it performs a final stroke stage of the assembly movement (C) of this housing (8) by causing a sliding of the rings (40) in this final stroke (C).

10. Electric or hybrid motor vehicle comprising an electric traction machine, characterized in that this machine is part of an assembly according to any one of claims 1 to 8.

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