Powertrain with interface part for supplying lubricant to a central bore of a shaft

Abstract

A system is equipped with a powertrain including: a) a first item of equipment (EQ1) comprising a shaft (A1) having an axial direction and comprising a central bore (AC) intended to carry a lubricant and an intake part (PA) bearing a rolling bearing (RA) and defining an open internal recess (LI), b) a housing (C2) comprising a supply channel (CA) having a first end (E21) receiving the lubricant and a second end (E22) opening into a passage (PC), and c) an interface part (PI) comprising a hollow tube (TC) having a first sub-part (SP1) fixedly and sealingly housed in this internal recess (LI) and a second sub-part (SP2) housed in this passage (PC) and provided with an external flange (CEP) bearing against the rolling bearing (RA) in order to position the shaft (A1) with respect thereto and an inlet (EL) supplied with lubricant via the second end (E22).

Description

DESCRIPTION TITLE: POWER UNIT WITH INTERFACE PIECE FOR SUPPLYING LUBRICANT TO A CENTRAL BORE OF A SHAFT The present invention claims priority from French application No. 2314546 filed on 20.12.2023, the content of which (text, drawings and claims) is incorporated herein by reference. Technical field of the invention

[0001] The invention relates to powertrains comprising equipment comprising a shaft, and more precisely the supply of lubricant to such a shaft. State of the art

[0002] Some systems, such as for example certain vehicles (possibly of the automobile type), comprise a powertrain (or GMP) comprising equipment comprising a shaft having an axial direction and comprising a central (axial) bore for carrying a lubricant and an intake part carrying a bearing, comprising a part of this central bore and housed in a casing. For example, such equipment may be a gearbox or an electric motor. Also for example, the lubricant which is carried by the central bore may be intended to lubricate at least one bearing of the GMP shaft line or synchronization devices of the shaft line of a gearbox. Also for example, the casing may be part of the equipment or of another piece of equipment of the GMP, such as for example a reducer.

[0003] To accommodate the lubricant in the central bore of the shaft, it has been proposed that the outer face of the intake portion of the shaft include a main cavity forming a loop and communicating with the central bore via at least one first supply channel making a non-zero angle with the axial direction, and that the casing comprises a second supply channel having a first end suitable for receiving the lubricant and a second end located opposite the main cavity to supply it with lubricant intended to supply the central bore via the (each) first supply channel.

[0004] Such an arrangement does not allow the shaft to be precisely positioned relative to the bearing. Furthermore, this arrangement is not compatible with a reduction in the axial length of the shaft, for example to achieve a reduction in mass.

[0005] Furthermore, when the lubricant reaches the central bore of the shaft by gravity, a lubricant leak does not cause a loss of efficiency. But when the lubricant is injected into the supply channel by a pump (possibly via a water / lubricant heat exchanger), a lubricant leak causes a loss of efficiency on the electrical balance of the powertrain.

[0006] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0007] For this purpose, it proposes in particular a powertrain suitable for equipping a system and comprising a casing and a first piece of equipment comprising a shaft having an axial direction and comprising, on the one hand, a central bore intended to transport a lubricant and, on the other hand, an intake part carrying a bearing, comprising a part of the central bore.

[0008] This powertrain is characterized by the fact that:

[0009] - that the intake portion of the shaft defines an open internal housing,

[0010] - that it comprises an interface part comprising a hollow tube having a first sub-part housed fixedly and in a sealed manner in the internal housing and a second sub-part partially housed in a passage of the casing and provided with an external collar bearing against the bearing to position the shaft relative to the latter and with an inlet, and

[0011] - that the casing comprises a supply channel having a first end suitable for receiving the lubricant and a second end opening into the passage to supply the inlet of the interface part with lubricant intended to supply the central bore via the hollow tube.

[0012] Thanks to this interface part, it is now possible not only to position the shaft in relation to the bearing, but also to supply the central bore with lubricant in a sealed manner.

[0013] The powertrain according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0014] - the internal housing may be open at an inlet face and may include an internal thread distant from the latter. In this case, the first sub-part may be provided with an external thread screwed onto the internal thread;

[0015] - in the presence of the first option, the external thread can be provided with a sealing paste participating in the sealing;

[0016] - the second sub-part may be provided, before the external collar and on an external face, with an annular groove housing a sealing segment;

[0017] - the feed channel can be perpendicular to the axial direction;

[0018] - the casing may be part of a second piece of equipment, and may be fixedly attached to the first piece of equipment;

[0019] - the first equipment may be an electric motor;

[0020] - in the presence of the last two options, the second equipment can be a reducer.

[0021] The invention also proposes a system comprising at least one powertrain of the type presented above.

[0022] For example, this system may constitute a vehicle, possibly of the automobile type. Brief description of the figures

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings, in which:

[0024] [Fig. 1] schematically illustrates, in a sectional view in a longitudinal and vertical plane, a part of an exemplary embodiment of a powertrain according to the invention, and

[0025] [Fig. 2] schematically illustrates, in a side view, an exemplary embodiment of an interface part of a powertrain according to the invention. Detailed description of the invention

[0026] The invention aims in particular to propose a GM powertrain intended to be part of a system, comprising a first equipment EQ1 comprising a shaft A1 provided with a central bore AC supplied with lubricant via an interface part PL

[0027] In the following, it is considered, by way of non-limiting example, that the system is a motor vehicle, such as a car. But the invention is not limited to this type of system. It relates in fact to any system comprising at least one powertrain (or GMP) comprising at least one shaft provided with a central bore for transporting a lubricant. Thus, it relates in particular to all vehicles (land, sea (or river), or air), devices (possibly household appliances), installations (possibly industrial), and buildings.

[0028] Furthermore, it is considered in the following, by way of non-limiting example, that the GMP GM comprises a first piece of equipment EQ1 constituting an electric motor and associated with a second piece of equipment EQ2 constituting a reducer. But the invention is not limited to this type of GMP. Thus, the GMP GM could comprise a first piece of equipment EQ1 constituting a gearbox, for example.

[0029] Figure 1 schematically illustrates a very small part of an exemplary embodiment of a GM powertrain (or GMP) according to the invention, suitable for equipping a system (here a motor vehicle), and comprising a PL interface part. More precisely, in the example illustrated without limitation, the GM GMP comprises, as indicated above, an electric motor machine EQ1 very partially illustrated and associated with a reducer EQ2 very partially illustrated.

[0030] As illustrated at least partially in Figure 1, the first equipment EQ1 (here an electric motor) comprises a shaft A1 having an axial direction da and comprising a central bore AC which must transport a lubricant and an intake part PA carrying on an external face a bearing RA and comprising a part of the central bore AC.

[0031] It will be noted that the shaft A1 may, optionally, be fixedly secured to another shaft forming part of the rotor of the electric motor EQ1. In this case, the central bore AC of the shaft A1 communicates with a central bore of the other shaft which communicates with at least one internal channel opening to the outside of this other shaft via a hole intended to supply at least one bearing of the electric motor EQ1 with lubricant from the shaft A1.

[0032] Furthermore, the intake part PA of the shaft A1 defines an internal housing Ll which is open at the level of an intake face FA (here located on the left side).

[0033] In addition, the GMP GM comprises a casing C2 having a supply channel CA comprising first E21 and second E22 opposite ends. The first end E21 is adapted to receive the lubricant. The second end E22 opens into a passage PC defined in the casing C2 to supply an inlet EL of the interface part PI (described later) with lubricant intended to supply the central bore AC via this interface part PL

[0034] It should be noted that in the example illustrated non-limitingly in figure 1 the casing C2 is part of the second equipment EQ2 (here a reducer). But this is not obligatory. Indeed, the casing C2 could be part of the first equipment EQ1.

[0035] It will also be noted that in the example illustrated non-limitingly in Figure 1 the lubricant is injected into the first end E21 of the AC supply channel by a pump (not shown), via a water / lubricant type heat exchanger. But, when the first equipment EQ1 is a gearbox, a pump can be dispensed with.

[0036] As illustrated at least partially in Figures 1 and 2, the interface part PI comprises a hollow tube TC having first SP1 and second SP2 sub-parts which extend mutually. The first sub-part SP1 is fixedly and sealingly housed in the internal housing L1, which means that when the shaft A1 is rotated the interface part PI is rotated in the same way.

[0037] The second sub-part SP2 is partially housed in the passage PC of the casing C2, and is provided, on its external face FE, with an external collar CEP (preferably annular) which rests against the bearing RA to position the shaft A1 relative to the latter (RA). It will be understood in fact that the interface part PI being fixedly secured to the shaft A1, when its CEP collar contacts the bearing RA, this allows the shaft A1 to be positioned very precisely in relation to the latter (RA). In addition, this advantageously allows the inner cage of the bearing RA to be blocked in rotation in relation to the shaft A1.

[0038] In addition, this second sub-part SP2 comprises an inlet EL which is fed into the passage PC of the casing C2 by the second end E22 of the supply channel CA (as indicated above). Thus, the lubricant which circulates in the supply channel CA can enter the hollow tube TC through the inlet EL of its second sub-part SP2, then join the central bore AC of the shaft A1.

[0039] The PI interface part therefore not only allows the shaft A1 to be positioned in relation to the bearing RA, but also allows the central bore AC to be supplied with lubricant in a sealed manner. In addition, since the lubricant is now supplied axially, and no longer radially, this makes it possible to reduce the axial length of the shaft A1, for example to achieve a reduction in mass.

[0040] For example, and as illustrated non-limitingly in Figure 1, the internal housing L1 may be open at its intake face FA and may comprise an internal thread FLI which is distant from this intake face FA. In this case, the first sub-part SP1 of the interface part PI may be provided with an external thread FLE which is screwed onto this internal thread FLI. This screwing contributes to the sealing, and the latter may be further increased by providing the external thread FLE with a sealing paste. For example, this sealing paste may be similar to that which is commonly used on crankshaft screws responsible for securely securing the flywheel on a heat engine. It will be noted that the sealing may be further increased by giving the external thread FLE thread locking properties.

[0041] But, in an alternative embodiment, the first sub-part SP1 of the interface part PI could be fixedly secured to the PA intake part of the A1 shaft by welding or gluing. But such a variant does not allow disassembly.

[0042] Also for example, and as illustrated non-limitingly and at least partially in figures 1 and 2, the second sub-part SP2 of the interface part PI can be provided, before the external collar CEP (and therefore here on the left) and on its external face FE, with an annular groove GA housing a sealing segment SE.

[0043] This advantageously makes it possible to prevent part of the lubricant which exits through the second end E22 in front of the inlet EL from escaping through the passage PC of the casing C2, defined to allow the housing of the second sub-part SP2 of the interface part PI, and ending up (here) in the first equipment EQ1.

[0044] Also for example, and as illustrated non-limitingly in Figure 1, the entire AC power channel may be perpendicular to the axial direction da. However, it could be envisaged, for example due to a lack of space, that the AC power channel is defined at an angle other than 90° relative to the axial direction da.

Claims

CLAIMS

1. Powertrain (GM) suitable for equipping a system and comprising a casing (02) and a first equipment (EQ1) comprising a shaft (A1) having an axial direction and comprising i) a central bore (AC) for transporting a lubricant and ii) an intake part (PA) carrying a bearing (RA) and comprising a part of said central bore (AC), characterized in that said intake part (PA) defines an open internal housing (L1), in that it comprises an interface part (PI) comprising a hollow tube (TC) having a first sub-part (SP1) housed fixedly and in a sealed manner in said internal housing (L1) and a second sub-part (SP2) housed partially in a passage (PC) of said casing (C2) and provided with an external collar (CEP) bearing against said bearing (RA) to position said shaft (A1) relative to the latter (RA) and with an inlet (EL),and in that said casing (C2) comprises a supply channel (CA) having a first end (E21) suitable for receiving said lubricant and a second end (E22) opening into said passage (PC) to supply said inlet (EL) with lubricant intended to supply said central bore (AC) via said hollow tube (TC).,

2. Powertrain according to claim 1, characterized in that said internal housing (Ll) is open at an intake face (FA) and comprises an internal thread (FLI) distant from the latter (FA), and in that said first sub-part (SP1) is provided with an external thread (FLE) screwed onto said internal thread (FLI).

3. Powertrain according to claim 2, characterized in that said external thread (FLE) is provided with a sealing paste participating in said sealing.

4. Powertrain according to one of claims 1 to 3, characterized in that said second sub-part (SP2) is provided, before said external collar (CEP) and on an external face (FE), with an annular groove (GA) housing a sealing segment (SE).

5. Powertrain according to one of claims 1 to 4, characterized in that said supply channel (CA) is perpendicular to said axial direction.

6. Powertrain according to one of claims 1 to 5, characterized in that said casing (C2) is part of a second equipment (EQ2) and is fixedly secured to said first equipment (EQ1).

7. Powertrain according to one of claims 1 to 6, characterized in that said first equipment (EQ1) is an electric motor.

8. Powertrain according to the combination of claims 6 and 7, characterized in that said second equipment (EQ2) is a reducer.

9. System, characterized in that it comprises at least one powertrain (GM) according to one of claims 1 to 8.

10. System according to claim 9, characterized in that it constitutes a vehicle.

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