AUTOMATIC FLUID PIPE CONNECTION DEVICE WITH IMPROVED SEALING AND GUIDANCE

Abstract

Device for automatically connecting two fluid pipes, comprising a nozzle (2) having at a front end a cylindrical part (10) guided in a sleeve (6) having an internal annular groove (24) containing a seal (26) which is compressed by this front cylindrical part (10), the sleeve (6) having behind the bore (22) an elastic stop ring (34) which automatically engages in an external circular groove of the sleeve at the end of the assembly position, the sleeve (6) comprising an internal guide tube (40) fixed in front of the seal (26), comprising an external cylindrical guide surface (46) which fits into the axial bore of the cylindrical front part (10) of the nozzle (2). Figure 2

Description

Title of the invention: AUTOMATIC FLUID PIPE CONNECTION DEVICE WITH IMPROVED SEALING AND GUIDANCE

[0001] The present invention relates to a device for automatically connecting two fluid pipes comprising improved sealing and guidance, as well as a motor vehicle comprising a cooling circuit of the powertrain equipped with such a connector.

[0002] A type of known automatic connection device, presented in particular by document FR-A1-3120674, comprises a male end piece fixed to the end of a fluid circulation pipe which fits axially into the rear end of a sleeve to form a sealed connection for the passage of this fluid.

[0003] The front end of the nozzle comprises a cylindrical front part which is guided first by a conical shape of the female part of the sleeve, to then fit into a bore at the bottom of this female part ensuring guidance between these two elements. The bore comprises an internal circular groove containing an annular seal made of an elastomer, which is tightened radially when the cylindrical end of the nozzle is introduced, to ensure a seal resistant to the pressure of the fluid passing through this connection.

[0004] The end piece comprises, behind the cylindrical part, an external groove receiving a clipping system comprising an elastic ring arranged transversely, which after the end piece has been completely inserted into the sleeve locks automatically by engaging in a circular groove in the end piece in order to ensure axial locking preventing it from being withdrawn under the pressure of the fluid.

[0005] The regular compression of the annular seal between the cylindrical front part of the end piece and the bottom of the circular groove of the sleeve must be carried out constantly on this contour, remaining within a tolerance interval of the compression factor in order to guarantee the sealing of the connection.

[0006] However, it is possible to use with the same sleeve different types of end pieces connected to pipes, comprising for the front cylindrical part variations in shape, surface condition or quality of the material used.

[0007] In particular, these tips may come from several suppliers using various materials or manufacturing processes with different qualities, or may have been deformed, resulting in defects in the circularity of the front cylindrical part or in the rigidity of this part which pose problems of tightening the sealing joint which is not within the required tolerance over the complete contour.

[0008] There are then risks of leaks, which in particular on a heat transfer fluid circuit of the powertrain of a motor vehicle can lead to breakdowns of the vehicle or engine failures.

[0009] The present invention aims in particular to avoid these problems of the prior art.

[0010] To this end, it proposes a device for automatically connecting two fluid pipes, comprising a nozzle having at a front end a cylindrical part guided in a sleeve having an internal annular groove containing a seal which is compressed by this front cylindrical part, the sleeve having behind the bore an elastic stop ring which automatically engages in an external groove of the sleeve at the end of the assembly position, this device being remarkable in that the sleeve comprises an internal guide tube fixed in front of the seal, comprising an external cylindrical guide surface which fits into the axial bore of the cylindrical front part of the nozzle.

[0011] An advantage of this connection device is that the sleeve comprising its guide tube remaining fixed in the bore, which guides from the inside the front of the axial drilling of the end piece, one obtains both an improved centering of the front cylindrical part, and if necessary a conformation of this front part to rectify its circularity by a small deformation in the case where it would have a circular shape defect.

[0012] The front cylindrical part of the tip is thus better centered in the sleeve, with an improved geometry of its surface compressing the seal, providing better regularity of tightening of this seal which is better distributed.

[0013] A sleeve is produced forming a single standard which can receive tips from different suppliers including variations in materials, manufacturing process or tolerance, while providing a more regular compression rate of the sealing gasket on the contour which makes it possible to ensure the sealing of the fluid.

[0014] The automatic connection device according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0015] Advantageously, the guide tube is fixed in the sleeve by radial tightening.

[0016] In this case, advantageously the sleeve comprises in front of the seal a cylindrical bearing surface tightly receiving a front part for locking the guide tube.

[0017] In addition, the outer guide surface may have a diameter which is smaller than that of the cylindrical clamping surface.

[0018] Advantageously, the external guide surface has a rearward entry chamfer for receiving the front part of the end piece.

[0019] Advantageously, the connection device comprising cir pipes fluid circulation fixed to the sleeve or nozzle, the internal diameter of the fluid passage in the guide tube has a diameter greater than or equal to that of the circulation pipes.

[0020] The invention also relates to a motor vehicle comprising a power unit equipped with a heat transfer fluid circuit for its cooling, remarkable in that it comprises circulation pipes which are connected to each other by connection devices comprising any one of the preceding characteristics.

[0021] The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description given below by way of example, with reference to the appended drawings in which:

[0022] [Fig. 1] shows in axial section an automatic connection device according to the prior art, equipped with its pipes; and

[0023] [Fig.2] shows in axial section an automatic connection device according to the invention.

[0024] [Fig. 1] shows a connection device arranged along an axis A having a direction AV, comprising a nozzle 2 fixed to the front end of a first circulation pipe 4, fitting into a sleeve 6 fixed to a second circulation pipe 8 to ensure a connection between these pipes with a seal allowing the passage of a fluid under pressure. The device comprises a quick locking system which engages automatically at the end of fitting to give axial resistance to this connection supporting the internal pressure.

[0025] The end piece 2 comprises successively, starting from the front, a front cylindrical part 10 having a thickness E1, and an external sealing surface 12 having a front entry chamfer 14, then a connecting cone 16 leading towards a rear cylindrical part 18 of greater diameter having a circular transverse groove 20.

[0026] The sleeve 6 comprises successively, starting from the front, a first bore 22 receiving in a fitted manner the external sealing surface 12, a circular transverse groove 24 receiving an annular elastomer sealing joint 26, then a cone 28 leading towards a second rear bore 30 receiving the rear cylindrical part 18, ending towards the rear with an entry chamfer 32.

[0027] An elastic stop ring 34 engaged in transverse grooves of the sleeve 6, has two substantially parallel arms returning inside the rear bore of this sleeve 30, which are separated during the advancement of the connecting cone of the end piece 16 to finish at the end of the assembly stroke by automatically descending into the transverse groove 20 of this end piece 2 in order to achieve axial locking.

[0028] However, in the different uses of industrialists or individuals, the same sleeve 6 can receive several end pieces 2, connected for example to various tools. Furthermore, motor vehicles, in particular hybrid or electric vehicles, have heat transfer fluid circuits connected to the powertrain and to the passenger compartment heating which can be complex. It is also possible to use on the same sleeve 6 end pieces from different suppliers having slightly different characteristics, in particular materials or manufacturing processes, with a compression factor of the annular seal 26 which is variable.

[0029] The centering and guiding of the cylindrical front part 10 of the end piece 2 in the sleeve 6, important for obtaining the quality of the tightening of the annular sealing joint 26, is ensured by the guiding length D of the external sealing surface 12 coming in front of this joint, which must have a sufficient length to ensure this guiding. It is then necessary to give the cylindrical front part 10 a total length comprising the addition of that of the entry chamfer 14, the guiding length D and the width of the internal groove 24.

[0030] [Fig. 2] shows an inner guide tube 40 comprising at the front a cylindrical locking part 42 which is clamped radially in a cylindrical bearing surface of the sleeve 44 arranged in front of its first bore 22, having a diameter smaller than that of this first bore, so as to ensure centering and locking of the tube in the sleeve 6.

[0031] The inner guide tube 40 comprises towards the rear, after the cylindrical locking part 42 and with a smaller diameter, a guide part 48 having an outer guide surface 46 ending in an entry chamfer 50, receiving in a fitted manner an inner bore 52 of the front cylindrical part 10 of the end piece 2.

[0032] The front cylindrical part 10 of the end piece 2 has a thickness E2 which is reduced compared to the thickness E1 of the same part of the device according to the prior art, so as to obtain an internal passage of the fluid in the guide tube 40 which is not reduced.

[0033] When the end piece 2 is advanced into the sleeve 6, its front cylindrical part 10 is introduced around the external guide surface 46 of the tube 40, which is facilitated by the rear entry chamfer 50 of this surface, then by continuing to press the end piece, its front chamfer 14 slides under the annular seal 26 which first compresses it and then slides it onto its external sealing surface 12.

[0034] When sliding the front cylindrical part 10 of the end piece 2 on the external guide surface 46 of the tube 40, it is both centered in the end piece 6 and, if necessary in the case of a geometry defect, reshaped this front part given by the guide surface forcing it inside thanks to the driving force applied by the operator who presses the end piece forward.

[0035] In the case of a pronounced defect in the geometry of the front part 10, for example an ovalization or an excessively narrow diameter, a certain correction of its shape is obtained which is transmitted to its external sealing surface 12 pressing on the annular seal 26. We then have a compression factor of the sealing seal 26 which is more regular over the complete contour, ensuring better sealing.

[0036] Furthermore, the centering and guiding of the cylindrical front part 10 of the end piece 2 in the sleeve 6 being ensured by its internal bore 52 bearing on the external guide surface 46 of the tube 40, which may have a significant length, the length d of this front part between the entry chamfer 14 and the internal groove 24 may be reduced, no longer having a centering and guiding role. A more compact connection device is obtained, which may have a reduced total length.

Claims

Claims

1. Device for automatically connecting two fluid pipes (4, 8), comprising a nozzle (2) having at a front end a cylindrical part (10) guided in a sleeve (6) having an internal annular groove (24) containing a seal (26) which is compressed by this front cylindrical part (10), the sleeve (6) having behind a bore (22) an elastic stop ring (34) which automatically engages in an external groove (20) of the sleeve (6) at the end of the assembly position, characterized in that the sleeve (6) comprises an internal guide tube (40) fixed in front of the seal (26), comprising an external cylindrical guide surface (46) which fits into the axial bore of the cylindrical front part (10) of the nozzle (2).

2. Connection device according to claim 1, characterized in that the guide tube (40) is fixed in the sleeve (6) by radial clamping.

3. Connection device according to claim 2, characterized in that the sleeve (6) comprises in front of the seal (26) a cylindrical bearing surface (44) tightly receiving a front locking part (42) of the guide tube (40).

4. Connection device according to claim 3, characterized in that the outer guide surface (46) has a diameter which is smaller than that of the cylindrical clamping surface (44).

5. Connection device according to any one of the preceding claims, characterized in that the external guide surface (46) has towards the rear an entry chamfer (50) for receiving the front part (10) of the end piece (2).

6. Connection device according to any one of the preceding claims, comprising fluid circulation pipes (4, 8) fixed to the sleeve (2) or to the end piece (6), characterized in that the internal diameter of the passage of the fluid in the guide tube (40) has a diameter greater than or equal to that of the circulation pipes (4, 8).

7. Motor vehicle comprising a powertrain equipped with a heat transfer fluid circuit for its cooling, characterized in that it comprises circulation pipes (4, 8) which are connected to each other by connection devices according to any one of the preceding claims.

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