WATERPROOFING DEVICE FOR A CABLE SHEATH TO AN OPENING IN A MOTOR VEHICLE APRON

Description

[0001] The present invention claims priority from French application 1903090 filed on March 26, 2019. technical field

[0002] The present invention relates to a device for sealing a cable sheath through an opening in the bulkhead of a motor vehicle separating two compartments of that vehicle. Previous technique

[0003] Motor vehicles typically include an engine compartment in which, in addition to the vehicle's propulsion engine, various accessory equipment are located; as well as a passenger compartment in which the driver and passengers are seated.

[0004] The passenger compartment is generally separated from the engine compartment by a bulkhead consisting of a sheet metal wall covered on the passenger side by a layer of soundproofing material, itself covered by upholstery.

[0005] In order to ensure the electrical connection between the various electrical and / or electronic equipment located in the passenger compartment and the battery supplying them located in the engine compartment, it is necessary to pass an electrical supply harness or bundle grouping all of these electrical connection cables through an opening made in the bulkhead of the vehicle.

[0006] However, the electrical power supply harnesses to be fitted in motor vehicles are generally supplied by the suppliers equipped with their connectors.

[0007] Therefore, when the beam has to pass through the apron, it is necessary to provide in the latter an opening large enough to allow the connectors to pass through, but then the beam itself has a diameter much smaller than the opening.

[0008] In order to obtain a good seal and as disclosed in particular in French application FR 2 747 449 A1, a conventionally sealed through-piece is mounted on the opening comprising a main body made of elastomeric material including a through-sleeve intended to allow the passage of the electrical supply bundle and having an enlarged part defining between it and the bundle a cavity for the injection of a coating material such as polyurethane inside the sleeve itself so as to ensure the seal between the through-piece and the bundle.

[0009] In addition to this electrical supply harness, it may also be necessary to pass other elements through the bulkhead, such as for example the sheath of the control cable for the interior opening of the vehicle's front hood (COIC).

[0010] Traditionally, the COIC cable sheath passes through the deck at another dedicated opening made in this deck and by means of specific sealing means, which presents many disadvantages, particularly in terms of the number of crossing pieces to be used and assembled.

[0011] It is known, in particular from application FR 2 937 192 A1, to pass the sheath of the cable for the interior opening of the front hood through the main elastomer body of the through piece ensuring the passage of the electrical supply harness.

[0012] Since this COIC cable is often damaged in the event of a front impact, it must be able to be easily disassembled in order to be replaced in the after-sales, which excludes sealing with the through piece by injecting a coating material (implementing such an injection operation is not feasible in the after-sales).

[0013] French patent application FR 3 066 332 A1 discloses a rigid plastic insert overmolded onto the COIC cable sheath and configured to be able to be forced through a corresponding hole in the main elastomer body into a sealed mounting configuration.

[0014] The insert includes retention means capable of cooperating with complementary means provided on the main elastomer body of the through piece to ensure axial retention of the insert in its sealed mounted configuration.

[0015] These retention means include an annular recess formed in the insert and intended to receive a complementary annular rib projecting radially inside the passage.

[0016] In practice, however, these retention methods prove to be ineffective and can lead to degradation of the elastomer through piece in case of excessive forcing during the insertion of the insert. Description of the invention

[0017] The present invention therefore aims to improve the situation.

[0018] For this purpose, it proposes a watertight conduit for a cable sheath through an opening in the bulkhead of a motor vehicle, comprising a conduit designed to be mounted watertight on said opening and comprising a main body made of elastomeric material including a through hole, said device also comprising a rigid elongated insert overmolded on said sheath and configured to be able to be forced through said hole into a watertight mounted configuration, said insert further comprising retention means capable of cooperating with additional means provided on said main elastomeric body to ensure axial retention of the insert in said watertight mounted configuration;characterized in that said retention means comprise a harpoon arranged at the downstream end of said insert and comprising a head provided with a plurality of teeth capable of cooperating by snapping, when said insert is introduced through said bore, with an annular rib projecting radially inside this bore.;

[0019] The use of such a harpoon ensures a gentler cooperation with the annular rib during the insertion phase of the insert through the bore, thus avoiding any risk of damage to the latter, while ensuring satisfactory anti-retraction retention of this insert once it is positioned in its sealed mounted configuration.

[0020] According to preferred characteristics of said device according to the invention: Each tooth is formed by a ramp with a curved ogive profile extending to a notch; said notches have a profile inclined obliquely upstream; said annular rib has a right-angled triangular cross-section; an axial clearance of between 1 and 3 mm is provided between said teeth and said annular rib in said mounted configuration of the insert; said retaining means also include a truncated conical shoulder arranged at the upstream end of said insert and being able to cooperate as a stop, at the end of the insertion of said insert through said bore, with a complementary truncated conical countersink made on the upstream outfeed edge of said bore.said main elastomer body comprises several annular grooves projecting radially inside said bore and adapted to cooperate in a hermetic manner, in said mounted configuration of the insert, with the external face of at least one interface portion of said insert; said bore and at least said interface portion of the insert have frustoconical profiles; said annular grooves have a triangular cross-section; and / or said insert comprises a gripping spool arranged at its downstream end and defining a receiving groove for a tool such as pliers or a wrench. Brief description of the drawings

[0021] The description of the invention will now be continued by a detailed example of an embodiment, given below by way of illustration but not limitation, with reference to the attached drawings, on which: [ Fig 1] is a perspective view of a device according to the invention for a watertight passage through an opening made in the firewall of a motor vehicle; [ Fig 2 ] represents a perspective view from another angle of the device according to the invention, on which the part located to the right of a cutting plane passing through the axis of the passage has been torn off; [ Fig 3 ] is a perspective view of the insert alone of the device according to the invention; and [ Fig 4 ] is a perspective view of the insert of the figure 3 from a different perspective. Detailed description

[0022] THE figures 1 and 2 show a device 1 according to the invention of a watertight passage through an opening made in a front panel of a motor vehicle not shown and separating the engine compartment from the passenger compartment of this vehicle.

[0023] Such a front apron is classically formed by a sheet metal to which is attached a plate, mat or similar made of a sound-absorbing material, itself covered, on the side opposite the sheet metal, with a layer of finishing material.

[0024] The device according to the invention comprises a through piece 10 including a main body of elastomer material 11 of ovoidal cross-section, and a ring 12 of a thermoplastic material more rigid than this main body 11 (for example, of polypropylene possibly reinforced with glass fibers) and including a plurality of tabs 13 provided to snap onto the edge of the opening provided in the front apron in order to secure the attachment of this through piece 10.

[0025] In order to improve its fit on the main body 11 and to prevent any relative movement between these two elements, the ring 12 advantageously comprises a plurality of tabs 14 projecting along axial directions from one of their annular end edges and embedded in the elastomer material (see figure 2 ).

[0026] The through piece 10 includes a through sleeve 15 made in the main body 11 made of elastomer, this sleeve 15 being intended to allow the passage of an electrical supply harness not shown suitable for ensuring the electrical connection between the various electrical and / or electronic equipment located in the passenger compartment and the battery supplying them located in the engine compartment.

[0027] The sleeve 15 includes an enlarged portion defining between itself and this electrical supply bundle a cavity provided for the injection of a coating material such as polyurethane inside the sleeve itself so as to ensure the seal between the through piece 10 and the bundle.

[0028] At its axial end intended to be inside the passenger compartment, the main body 11 includes a first flexible lip 16 intended to come into contact with the face of the apron located on the passenger compartment side at the periphery of the opening.

[0029] Similarly, at its axial end intended to be inside the engine compartment, the main body 11 includes a second flexible lip 17 intended to come into contact with the face of the apron located on the engine compartment side at the periphery of the opening.

[0030] The presence of these two flexible lips 16, 17 ensures excellent acoustic, air and moisture sealing between the engine compartment and the passenger compartment at the periphery of the through piece 10.

[0031] The first flexible lip 16 is further shaped to be able to occupy also a reversed mounting position (not shown in the figures) allowing the engagement of the through piece 10 through the opening provided in the apron (this lip being folded back by the operator into its normal position after the installation of the through piece 10).

[0032] The through piece 10 finally includes a through hole 18 made in the main body 11 made of elastomer, this hole 18 being delimited by a lateral face whose diameter gradually reduces according to a truncated conical profile between its first end intended to open on the engine compartment side and its second end intended to open on the passenger compartment side.

[0033] In addition to this through piece 10, the watertight through device 1 according to the invention also includes an elongated rigid insert 30 made of plastic material overmolded on the cable 2 for the interior opening control of the front hood of the vehicle, and configured so that it can be inserted, from the engine compartment, by force through the hole 18.

[0034] In the remainder of this description and by convention, the terms "upstream" and "downstream" will be defined in relation to the direction of introduction of this insert 30 into the bore 18.

[0035] The insert 30 comprises two frustoconical portions, upstream 31 and downstream 32, which interface with the lateral face of the bore 18. These portions are separated by an intermediate portion 33 of smaller cross-section that does not interact with the lateral face of the bore 18, thus limiting the effort required for the operator responsible for assembly to insert the insert 30. Extending over a shorter length than the upstream frustoconical portion 31, the downstream portion 32 has a frustoconical profile that coincides with the downstream extension of the frustoconical profile of the upstream portion 31. Due to its lack of interaction with the lateral face of the bore 18, the intermediate portion 33 provides a prime location for the injection points of the plastic material during the molding of the insert 30, where surface imperfections may occur.This intermediate portion 33 also advantageously presents a square section so as to facilitate the application of markings of all types of information (reference or serial numbers, date, text, technical characteristics, standards, etc.) on at least one of its four flat faces.

[0036] To ensure the sealing of the assembly, the main elastomer body 11 of the through piece 10 has several annular grooves 19, 20 projecting radially inside the bore 18 from its lateral face and capable of cooperating in a sealing manner in the mounted configuration of the insert 30 with the external faces of its two frustoconical interface portions 31, 32.

[0037] More specifically, the main body 11 comprises two upstream annular gadroons 19 cooperating with the longer upstream frustoconical interface portion 31, and a downstream annular gadroon 20 cooperating with the shorter downstream frustoconical interface portion 32.

[0038] Providing a larger number of upstream grooves 19 ensures better axial centering of the insert 30 in the bore 18.

[0039] The gadroons 19, 20 advantageously have a triangular cross-section which minimizes the contact surfaces of these with the truncated conical interface portions 31, 32 so as to reduce the assembly effort for the operator while ensuring an excellent level of sealing.

[0040] The insert 30 also includes retention means capable of cooperating with complementary means provided on the main elastomer body 11 of the through piece 10 to ensure the placement and axial retention of the insert 30 in its mounted configuration where sealing is ensured.

[0041] These restraining means consist of a harpoon 34 and a shoulder 40 arranged respectively at the downstream end and the upstream end of the insert 30.

[0042] The harpoon 34 comprises a cylindrical section 36 extending axially from the downstream frustoconical interface portion 32, and a cruciform head 37 surmounting this cylindrical section 36 and adapted to cooperate by snapping with an annular rib 21 of the main body 11 (see figure 2 ) projecting radially inside the bore 18 from the downstream end portion of its lateral face so as to prevent accidental removal of the insert 30 after its assembly.

[0043] As illustrated on the figures 3 and 4 , the cylindrical section 36, has a smaller circular section than that of the downstream end of the downstream truncated conical portion 32 so as not to cooperate with the lateral face of the bore 18 and to limit the effort of introducing the insert 30 for the operator in charge of the assembly.

[0044] Still referring to figures 3 and 4 , the cruciform head 37 includes four clipping teeth 38 angularly distributed regularly around its perimeter and each formed by a ramp with a curved ogive profile 38A extending to a step 38B joining the cylindrical section 36.

[0045] This ogival shape of the teeth 38 allows for a progressive deformation of the annular rib 21 in order to facilitate the introduction of the insert 30.

[0046] In order to allow the annular rib 21 to be turned over without being damaged during the dismantling of the insert 30, it advantageously has a right-angled triangle section while the teeth 38B have a profile inclined diagonally upstream.

[0047] Furthermore, and as can be seen on the figure 2 A slight axial play is provided between the teeth 38 of the harpoon 34 and the annular rib 21 when the insert 30 is in its mounted configuration, so as to prevent any risk of the harpoon 34 disengaging due to the expansion of the elastomer material forming the main body 11 of the through piece 10 under the effect of the temperature stresses to which it may be subjected. This play is preferably between 1 and 3 millimeters and advantageously equal to 2 mm.

[0048] Featuring a truncated conical profile whose diameter narrows from upstream to downstream, the shoulder 40 is intended to cooperate at the end of the assembly of the insert 30 with a complementary truncated conical countersink 22 made on the upstream through edge of the bore 18, so as to prevent the operator from axially pushing the insert 30 beyond the desired position where the seal would no longer be properly ensured.

[0049] Providing truncated conical contact surfaces helps to limit the axial displacement of the insert 30 which can be caused by the expansion of the elastomer material forming the main body 11 of the through piece 10, so as to preserve the seal (the annular grooves 19, 20 remaining crushed against the external faces of its two truncated conical interface portions 31, 32).

[0050] The insert 30 also includes gripping means arranged at its downstream end and suitable for grasping with a tool such as pliers or a flat key so as to facilitate its removal by an after-sales operator if necessary.

[0051] These gripping means consist of a coil 41 formed of a central axial hub extending between two transverse disc-shaped flanges, and defining an annular receiving groove 42 for such a tool.

[0052] In some unrepresented variants, the harpoon head is shaped differently. In particular, the number, profile, and arrangement of its teeth may vary.

[0053] According to other unrepresented embodiment variants, the number, profile and dimensions of the interface portions of the insert are also different.

[0054] According to yet other variations in implementation: the hole made in the main elastomer body is cylindrical; the number and / or the cross-section of the grooves are different; and / or the gripping means are shaped differently.

[0055] Finally, it is recalled that the present invention is not limited to the embodiments described and represented, but encompasses any variant of execution within the reach of a person skilled in the art.

Claims

1. Device for the leaktight passage of a cable sheath (2) through an opening of a motor vehicle apron, comprising a passage piece (10) provided to be mounted in a leaktight manner on said opening and comprising a main body made of elastomer material (11) comprising a through-hole (18), said device also comprising a rigid elongate insert (30) overmolded on said sheath (2) and configured to be able to be forced through said hole (18) to a leaktight mounted configuration, said insert (30) further comprising suitable retaining means (34, 40) cooperating with complementary means provided on said main elastomer body (11) to ensure the axial retention of the insert (30) in said sealed mounted configuration; characterized in that said retaining means comprise a harpoon (34) arranged at the downstream end of said insert (30) and comprising a head (37) provided with a plurality of teeth (38) capable of cooperating by snap-fastening, when said insert (30) is introduced through said hole (18), with an annular rib (21) projecting radially inside this hole (1) 8).

2. Sealed passage device according to Claim 1, characterized in that each said tooth (38) is formed by a ramp with a curved ogival profile (38A) extending as far as a tooth (38B).

3. Sealed passage device according to Claim 2, characterized in that the said teeth (38B) have a profile which slopes upstream.

4. Sealed passage device according to one of Claims 1 to 3, characterized in that the said annular rib (21) has a cross-section in the form of a right-angled triangle.

5. Sealed passage device according to one of Claims 1 to 4, characterized in that an axial clearance of between 1 and 3 mm is provided between the said teeth (38) and the said annular rib (21) in the said mounted configuration of the insert (30).

6. Sealed passage device according to one of Claims 1 to 5, characterized in that the said retaining means also comprise a frustoconical shoulder (40) arranged at the upstream end of the said insert (30) and being capable of cooperating in abutment, at the end of the introduction of the said insert (30) through the said bore (18), with a complementary frustoconical countersink (22) formed on the upstream emerging edge of the said bore (18).

7. Sealed passage device according to one of Claims 1 to 6, characterized in that the said elastomer main body (11) comprises several annular beads (19, 20) projecting radially inside the said bore (18) and capable of cooperating in a sealed manner, in the said mounted configuration of the insert (30), with the outer face of at least one interface portion (31, 32) of this insert (30).

8. Sealed passage device according to Claim 7, characterized in that the said bore (18) and the at least said interface portion (31, 32) of the insert (30) have frustoconical profiles.

9. Sealed passage device according to either of Claims 7 and 8, characterized in that the said annular beams (19, 20) have a section of triangular shape.

10. Sealed passage device according to one of Claims 1 to 9, characterized in that the said insert (30) comprises a gripping reel (41) arranged at its downstream end and defining a receiving groove for a tool such as a clamp or a flat key.