FR3085197A1 - DYNAMIC JOINT OF INTERFACE BETWEEN TWO MOBILE ROOMS ROTATING IN RELATION TO THE OTHER, INCLUDING A BREAKABLE LID - Google Patents

Abstract

The subject of the invention is a dynamic interface seal (1) between two moving parts which rotate in relation to one another. The seal (1) comprises at least one flexible lip (5) formed between two axially opposite openings (A1) of the seal (1), including an inlet opening (10) configured as an inlet passage for one of said movable parts through the seal (1). The seal (1) comprises at least one cover (9) for closing the opening (10) of the seal inlet (1), which is breakable under the effect of an axial thrust exerted against said cover (9 ).

Description

Dynamic interface seal between two moving parts rotating in relation to each other, incorporating a breakable cover.

The present invention relates to dynamic joints between two moving parts that rotate in relation to each other, incorporating at least one sealing lip. More specifically, an application of such a seal relates to the seal between a motor shaft and a bearing of a gearbox receiving it, gear motor in particular. Thus, the invention relates more specifically to the interface modalities between a drive shaft housed inside a fixed bearing.

Generally, a drive shaft of a motor machine is rotatably coupled to a drive shaft to be driven which is housed in a housing. The housing comprises at the input of the motor shaft a bearing which receives it and / or which houses a dynamic interface seal between the motor shaft and the bearing. The seal is commonly provided with at least one flexible sealing lip rubbing against the motor shaft, to give the housing a seal against the outside.

For the assembly between the driving shaft and the receiving shaft, these include cooperating coupling reliefs capable of providing their junction with one another in rotation, such as for example grooves. The flexible lip that comprises the dynamic seal then bears on a smooth surface of the drive shaft, formed upstream of said relief in the direction of introduction of the drive shaft inside the bearing. However, there is a risk of injury to the flexible lip by the drive shaft during its introduction inside the bearing, which consequently affects the seal obtained between the bearing and the rotating shaft, or even induced ultimately a risk of tearing the lip during use.

To overcome this drawback, it is known to add to the dynamic seal a PTFE lip (according to the acronym of PolyTétraFluoroEthylène), known to be more robust than flexible sealing lips, as shown for example in the document FR 3,007,485 A1.

The PTFE lip is placed on the dynamic seal upstream of the flexible sealing lip which it comprises, in the direction of fitting of the motor shaft inside the bearing. In other words, the PTFE lip is placed on the dynamic seal between its inlet for receiving the motor shaft and the flexible sealing lip. Thus, the PTFE lip provides a recovery of the force generated by the fitting of the motor shaft through the dynamic seal, and makes it possible to center the motor shaft inside the bearing before it is brought into contact against the flexible sealing lip of the dynamic seal.

Furthermore, there may be a case in which a housing for receiving a motor shaft is stored while waiting for its use. This is for example the case for a geared motor intended to receive a motor shaft of a motor machine. Indeed, the gearmotor and the motor machine are produced industrially separately from each other. This implies that a reduction motor and / or an electric machine intended to be coupled after their individual manufacture, can be stored for a more or less long period while awaiting their use.

In this case, there is the problem of a risk of intrusion of particles inside the geared motor housing during its storage period. In fact, during the storage of the gearmotor, particles can be admitted inside the housing through the opening or openings that the housing has for the reception of the motor shaft of the motor machine, including at least one inlet opening. intake of the motor shaft inside the housing.

This being to be avoided, it is then traditional to install a plug for closing said openings while awaiting the use of the geared motor. Such plugs are installed after the gearmotor has been manufactured, and are removed when it is assembled with the driving machine. The caps being consumable articles, these are then discarded. Consequently, this induces an untimely waste surplus and an additional cost of the driving machine which are to be avoided.

An object of the present invention is a dynamic interface seal between two moving parts which rotate in relation to each other, comprising at least one flexible sealing lip. Another object of the present invention is a sealing device equipping a bearing for receiving a rotating shaft, the bearing being provided with a dynamic seal according to the invention. Another object of the invention is a method of assembly between a receiving shaft and a motor shaft extending axially through at least one bearing provided with a dynamic seal according to the invention. Another object of the present invention is a gearbox comprising a housing providing a bearing provided with a sealing device according to the invention. Another object of the invention is a powertrain of a motor vehicle comprising a driving machine and a gear motor configured in a speed variation box according to the invention, as well as a motor vehicle equipped with such a powertrain .

An object of the invention is to provide a dynamic seal capable of protecting a bearing landing of a rotating shaft vis-à-vis an intrusion of particles inside a housing providing said bearing. It is more particularly targeted by the invention to obviate said intrusion of particles inside the housing, both in the storage phase of the housing and in the use phase of the housing.

Another object of the invention is to propose a solution at lower costs to protect said housing from said so-called particle intrusion. It is more particularly targeted by the invention to limit the costs of the solution sought, in particular concerning the structural costs and / or the costs of putting the dynamic seal into service under the invention.

Another object of the present invention is to provide a solution to protect said housing from said so-called particle intrusion which does not affect, or even improves, the durability of operation of the dynamic seal.

The aims of the present invention are achieved individually or in combination by applying the following provisions.

A dynamic interface seal between two moving parts rotating in relation to one another according to the invention, comprises at least one flexible lip formed between two axially opposite openings of the seal, including an inlet opening configured in admission passage of one mobile of said parts through the seal.

In this context, the dynamic seal of the invention is recognizable in that it comprises at least one seal for closing the inlet opening of the seal, which is breakable under the effect of an axial thrust exerted against said seal.

In other words, the seal of the invention incorporates a cover preventing the passage of particles through the seal from its inlet opening, or conversely to the passage of lubricant towards the outside of the seal as referred to below. Thus when the seal is installed in a bearing formed inside a housing and axially traversed by said movable part, the housing is protected from an intrusion of particles upstream of the seal in the axial direction of introduction of the part. movable through the seal towards the inside of the housing, or vice versa of a flow of lubricant out of the housing as referred to below. The cover is in particular easily integrated into the seal at lower costs and makes it possible to isolate the box from its external environment, both in the storage phase before it is put into service and in the use phase of the box and so of the joint.

Following the axial introduction of the moving part through the seal, the moving part exerts an axial thrust force against the cover, which causes it to break by punching when the seal is put into service, the cover then being torn, or preferably cut, by the peripheral stop of the end face of the movable part axially introduced through the joint.

In addition, the protection of the housing vis-à-vis the external environment is obtained without requiring a specific operation of removal of the cover when the seal is put into service, or in other words during the introduction of said part. mobile through it.

The cover also provides assistance to an operator who manually introduces the moving part through the seal. The axial sliding of the moving part towards the flexible lip is slowed down by the resistance of the cover to its rupture. The operator is then forced to pay attention to the pushing force which he exerts against the cover via the moving part in order to adapt the amplitude thereof, with the effect of limiting the risk of deterioration of the flexible lip by the moving part introduced through the joint.

Preferably, said at least one cover comprises a circular weakening line formed by discontinuous imprints.

Such a weakening line makes it possible to cause the lid to be cut along a cutting perimeter predefined by the weakening line. The cutting of the cover by the moving part can thus be carried out by the operator under the effect of a moderate thrust force. The diameter of the weakening line can advantageously be defined so as to guide the operator radially during the introduction of the moving part through the joint, to assist it in centering the moving part at least relative to the flexible lip.

Thus, according to one embodiment, the diameter of said weakening line is defined according to a nominal centering diameter of the moving part through the joint. The diameter of the weakening line is preferably less than the inside diameter of the flexible lip intended to bear against a smooth surface of the moving part formed upstream, according to the direction of introduction of the moving part through the seal, a section of the moving part comprising at least one interlocking relief with a part to be driven in rotation.

The cover is preferably made from a more rigid material than that from which the flexible lip is made, such as for example being made from a PTFE. More particularly according to one embodiment, the cover is formed from a PTFE disc integrated into said seal.

Thus, as a result of the rupture of the cover by the moving part, an initial conformation of the disc cover is then put in a ring conformation when the seal is put into service. The inner recess of the ring forms an axial guide member for the moving part towards the flexible lip and a member for centering the moving part with respect to the flexible lip. This also provides assistance to the operator during the commissioning of the seal. This also provides a radial stressing of the moving part by the ring coming from the cover when it passes through it, which improves the centering of the moving part with respect to the joint.

The invention also relates to a device for sealing a housing vis-à-vis the external environment. The housing provides at least one landing for receiving said movable part which is open to the external environment of the housing. According to the invention, the sealing device is recognizable in that it comprises at least one dynamic seal according to the invention. Said at least one dynamic seal is mounted inside said at least one bearing at at least one of its axial ends open to the external environment of the housing.

As previously mentioned and in addition to the advantages provided by the invention already indicated, the cover also forms an obstacle to the outflow to the outside of the housing of any surplus lubricant contained in the housing after its manufacture and / or after quality control of the housing.

The invention also relates to a method for mounting a said movable part inside a said housing equipped with a sealing device according to the invention.

The method of the invention is recognizable in that it comprises a step of rupture of the cover by said movable part during its axial introduction inside said at least one bearing.

The subject of the invention is also a gearbox comprising a housing providing at least one bearing for receiving a motor shaft. The gearbox of the invention is recognizable in that it is equipped with at least one sealing device according to the invention, said drive shaft constituting said movable part.

According to one embodiment, the speed variation box comprising two said bearings formed at its respective axial ends, each of said bearings is equipped with a said sealing device.

The subject of the invention is also a set of movement transmission members, comprising a motor machine provided with a said drive shaft for driving in rotation of at least one receiving shaft fitted to a speed variation box in accordance with l 'invention. Said set of movement transmission members is in particular part of a powertrain of a motor vehicle.

The invention also relates to a motor vehicle recognizable in that it is equipped with an assembly according to the invention.

The engine is potentially a combustion engine. The invention is preferably applied in the context of an electric power drive machine. Such an electric vehicle propulsion energy machine is capable of equipping a vehicle exclusively with electric propulsion energy or a hybrid energy vehicle whose propulsion is selectively supplied by an electric machine or a combustion engine.

An exemplary embodiment of the present invention will be described in relation to the figures in the appended plate, in which:

-) Figure 1 is an illustration in axial section of a dynamic joint according to an exemplary embodiment of the invention.

-) Figure 2 is a perspective illustration of a cover that includes the dynamic seal shown in Figure 1.

-) Figure 3 is composed of several diagrams (a), (b) and (c), successively illustrating in axial section a method of mounting a motor shaft inside a housing fitted with a dynamic seal shown in figure 1.

-) Figure 4 is a perspective view of the cover shown in Figure 2, after being cut by the motor shaft shown in the diagrams in Figure 3.

The figures and their detailed descriptions of an embodiment of the invention can be used to define it better, if necessary in relation to the general description which has just been made.

In FIGS. 1 to 4, a dynamic annular seal 1 of axis A1 is configured to provide a seal between two moving parts which rotate in relation to each other, shown in the diagrams in FIG. 3. In the diagrams in FIG. 3, a first part is a fixed part formed by a housing 2 and a second part is a part which can move in rotation formed by a motor shaft 3.

The seal 1 is housed in a bearing 4 formed by the housing 2, and comprises a flexible lip 5 providing sealing between the housing 2 and the motor shaft 3. The internal perimeter of the flexible lip 5 is provided for this purpose. bear against a smooth surface 6 of the drive shaft 3 formed by a section 15 upstream of the drive shaft 3, which is placed upstream of the seal 1 in the direction S1 of introduction of the drive shaft 3 through the bearing 4, and including through the seal 1, from the outside of the housing 2 as illustrated in the diagram (c) of FIG. 3.

The housing 2 is in particular a housing of a gearbox with at least one receiving shaft 7 provided to be driven in rotation by the motor shaft 3. For this purpose, the motor shaft 3 typically comprises a member for rotating the receiving shaft 7, formed by an interlocking relief 8 cooperating with a relief 8 ′ of complementary shape that includes the receiving shaft 7, such as, for example, grooves according to the illustrated embodiment .

In FIGS. 1 and 2, as well as in diagram (a) of FIG. 3, the seal 1 comprises a cover 9 for closing an inlet opening 10 formed axially on the seal 1, by forming a passage d admission of the rotating shaft 3 through the seal 1 towards the inside of the housing 2. The cover 9 is formed by a wall which has a ring 11 integrated into the seal 1. The ring 11 is made from a material, PTFE in particular, which is more rigid than the elastomer from which the flexible lip 5 comes.

In the direction S1 of axial introduction of the motor shaft 3 inside the housing 2, and therefore through the seal 1 as illustrated in the diagrams of Figure 3, the cover 9 is formed between the flexible lip 5 and the inlet opening 10 which comprises the seal 1. When the seal 1 is installed inside the housing 2 as illustrated in the diagram (a) of FIG. 3, the cover 9 obstructs the introduction of particles towards the interior of the housing 2 and / or of the flow out of the housing 2 of a lubricating fluid potentially present inside the housing 2.

In FIG. 1 and FIG. 2, the cover 9 comprises a circular embrittlement line 12 to cause it to be cut through the periphery of the end face 13 of the motor shaft 3 which is oriented towards the seal 1 when it is introduced. axial inside the bearing 4. The diameter D1 of the weakening line 12 is substantially equal to the diameter D3 of said end face 13 of the motor shaft 3.

Thus under the effect of an axial thrust force exerted against the cover 9 during the introduction by an operator of the drive shaft 3 inside the housing 2, said end face 13 of the drive shaft 3 cut the cover 9 along the line of weakness as illustrated in the diagram (b) of Figure 3. More particularly visible in detail 2a of Figure 2, the line of weakness 12 is formed of discontinuous imprints 12a weakening l cover 9 along its thickness which is oriented along the axis A1 of extension of the seal 1.

More particularly visible in FIG. 1 and in the diagrams of FIG. 3, the weakening line 12 has a diameter D1 less than the internal diameter D2 of the flexible lip 5. When the drive shaft 3 cuts and crosses the cover 9 as illustrated in diagram (b) of FIG. 2, the flexible lip 5 is thus diametrically distant from the drive member formed from said nesting relief 8 which comprises the motor shaft 3 for the drive of the receiver shaft 7.

In diagram (a) of FIG. 3, the operator axially approaches A1 the driving shaft 3 towards the joint 1 in said direction S1 of axial insertion A1 of the driving shaft 3 inside the bearing 4, and therefore through the joint 1. This has the effect of cutting the cover 9 along the line of weakness 12 whose diameter D1 corresponds to the diameter D3 of the end of the motor shaft 3, which is provided with interlocking reliefs 8 forming the drive member equipping the end 16 of the motor shaft 3 intended to be coupled with the receiving shaft 7. The cover 9 then has a ring-shaped configuration 17 as illustrated in FIG. 4.

The operator then continues the introduction of the motor shaft 3 through the seal 1 as illustrated in diagram (b) of Figure 3. The rigidity of the material from which the cover 9 provides assistance to the operator for axial guidance and axial centering A1 of the drive shaft 3 through the seal 1, via the axial recess 14 formed by the ring 17 formed by the cover 9 previously cut.

When the drive shaft 3 is coupled to the receiver shaft 7, the flexible lip 5 bears on said section 15 of the drive shaft 3 with a smooth surface 6 formed as an extension of its end 16 provided with interlocking reliefs 8, as illustrated in diagram (c) of FIG. 3. When the motor shaft 3 and the receiving shaft 7 are coupled, said smooth surface section 15 of the motor shaft 3 pushes the portion towards the interior of the housing 2 18 of the ring 17 coming from the cover 9 and lasting after its cutting.

According to the illustrated embodiment, the seal 1 is mounted inside 5 of an input bearing 4 through which the motor shaft 3 is introduced inside the housing 2. According to an embodiment not shown, the drive shaft 3 may also include an end section extending axially towards the inside of the housing 2. The drive shaft 3 is then preferably supported via said end section by an output bearing provided by the housing 2 to its end, called the outlet end, which is axially opposite its inlet end via which the motor shaft 3 is introduced inside the housing 2. The motor shaft 3 then potentially emerges from the housing 2 through its outlet end formed by said terminal section. In this case, the outlet bearing being open on the outside of the housing 2, the outlet bearing is also provided with a dynamic seal 1 according to the invention.

Claims (10)

1, -Joint (1) interface dynamic between two parts (2,3) movable in rotation relative to each other, the seal (1) comprising at least one flexible lip (5) formed between two openings axially (A1) opposite the seal (1), including an inlet opening (10) configured as an inlet passage of one of said moving parts (3) through the seal (1), characterized in that the seal (1) comprises at least one cover (9) for closing the opening (10) for entering the seal (1), which is breakable under the effect of an axial thrust exerted against said cover (9). 2, - Joint (1) according to claim 1, characterized in that said at least one cover (9) comprises a line of embrittlement (12) circular formed of imprints (12a) discontinuous. 3, - Joint (1) according to claim 2, characterized in that the diameter (D1) of said weakening line (12) is defined according to a nominal centering diameter of the moving part (3) through the joint (1 ), the diameter (D1) of the embrittlement line (12) being less than the inside diameter (D2) of the flexible lip (5). 4, - Seal (1) according to any one of claims 1 to 3, characterized in that the cover (9) is formed of a PTFE disc integrated in said seal. 5, - Sealing device for a housing (2) vis-à-vis the external environment, the housing (2) providing at least one bearing (4) for receiving a said moving part (3) which is open to the external environment of the housing (2), characterized in that the sealing device comprises at least one dynamic seal (1) according to any one of claims 1 to 4, said at least one seal (1) dynamic being mounted inside said at least one bearing (4) at at least one of its axial ends open to the external environment of the housing (2). 6, - Method for mounting a said movable part (3) inside a said housing (2) equipped with a sealing device according to claim 5, characterized in that the method comprises a step of rupture of the cover (9) by said movable part (3) during its axial introduction (A1) inside said at least one bearing (4). 7, - Variable speed gearbox comprising a housing (2) providing at least one bearing (4) for receiving a motor shaft (3), characterized in that the variable speed gearbox is equipped with at least one sealing device according to claim 5, said drive shaft (3) constituting said moving part. 8, - Gearbox according to claim 7, characterized in that the gearbox comprising two said bearings (4) formed at its respective axial ends, each of said bearings (4) is equipped with a said device sealing. 9, - Set of movement transmission members comprising a drive machine provided with a said drive shaft (3) for rotating the rotation of at least one receiving shaft (7) fitted to a speed variation box according to claim 7 or 8, characterized in that said set of movement transmission members is part of a powertrain of a motor vehicle. 10, -Motor vehicle characterized in that the vehicle is equipped with an assembly according to claim 9.