EP0854998A1

EP0854998A1 - Quick-connect fluid-tight coupling

Info

Publication number: EP0854998A1
Application number: EP96937365A
Authority: EP
Inventors: Daniel Baron
Original assignee: Manuli Auto France SA
Current assignee: Manuli Auto France SA
Priority date: 1995-10-30
Filing date: 1996-10-30
Publication date: 1998-07-29
Also published as: FR2740532B1; DE29680971U1; FR2740532A1; WO1997016673A1; JP2000509464A

Abstract

A fluid-tight coupling (1) including an end (2) of a rigid tube (3) inserted into a cylindrical bore (4) in a part (5) or a second tube. The rigid tube end comprises a first end portion (8) provided with at least one gasket (11) and a second portion (16) with a radial circumferential projection (20) having frusto-conical flanks. The bore (4) ends in a substantially ring-shaped chamber (25) extending radially outwards opposite the projection (20) and being defined on one side by a retaining lip (26) which has an edge radially located at a distance from the outer surface of the second portion slightly above the level of the projection. The coupling comprises a circular spring (31) fitted around said second portion (16) and arranged between the projection (20) and the inner surface of the lip (26) to prevent relative telescopic disengagement of the tube end (2) and the bore (4).

Description

WATERPROOF QUICK CONNECT

The present invention relates to a tight fitting of the type comprising a rigid tube end piece inserted in a cylindrical bore formed in a part or by a second tube, the rigid tube end piece comprising a first end portion provided with at least a seal between the internal face of the bore and the external face of said first portion of the tube end piece.

It finds a particularly important, although not exclusive, application in the field of sealed, snap-on and removable fittings, for refrigerant gas circuits, for example used in air conditioning circuits for motor vehicles.

There are already known tight connections with quick connection / disconnection of two tubes of the type described above. The attachment of such tubes to each other is effected by the return of a flared end portion of one of the tubes in a lip cage provided with an elastic retention member and integral with the other tube. Such connections have drawbacks. In fact, the flaring attachment system, in particular in the presence of materials such as aluminum, does not make it possible to withstand sufficient pressure before bursting for all the diameters of tubes used. Furthermore, the tensile strength of one tube relative to the other is limited so that the specifications of car manufacturers, which are more and more restrictive, are no longer respected. The manufacture of such fittings is also expensive (machining by chip removal) or difficult, if not impossible (machining by rolling).

Furthermore, such fittings are not suitable for the junctions between tube and non-tubular part. The sealing by O-ring of the fittings of the prior art is also not, in general, sufficient taking into account the manufacturing tolerances of the various components. The diameters of the O-rings can then turn out to be too small, which results in compression which does not ensure good sealing.

The present invention aims to provide a tight fitting which better meets those previously known to the requirements of practice, in particular in that it allows easy and less expensive manufacturing, in that it allows direct mounting which is not limited to connection between two tubes, in that it guarantees optimal compression with high standardization while respecting excellent mechanical strength.

To this end, the present invention provides in particular a tight fitting of the type described above, characterized in that the tube end piece comprises a second portion at least partially inside the bore having radially on its periphery a projection with frustoconical blanks, in that the bore ends in a substantially annular chamber s' extending radially outward opposite the projection with frustoconical blanks and terminated on one side by a radial internal blocking face and on the other side directed towards the end of the part or towards the outside of the second tube by a retaining lip the edge of which is radially situated at a distance from the external face of the second portion slightly greater than the height of said frustoconical blank projection and in that it comprises a circular spring threaded on said second portion, interposed between the projection and the internal face of the lip to prevent the relative telescopic release of the tube end piece and the bore. In advantageous embodiments, recourse is had to one and / or the other of the following arrangements: the second portion comprises a sleeve forming said projection, threaded and fixed on the tube end-piece; the second portion of the tube end-piece is delimited with respect to the first portion of the tube by a first fold of the wall of said tube end-piece, extending radially, projecting towards the outside of the end-piece and at 1 'inside the bore; - The rigid tube end piece has a second ply extending radially, projecting outwardly from said end piece, located at a distance from the first fold on the side opposite the end of said end piece, said folds forming longitudinal locking stops. on either side of the sleeve threaded on said endpiece;

- The second portion is formed in one piece with the first portion of the rigid tube end piece; the connection being made between two tubes, the chamber is constituted by an attached end cage, fixed immovably on the end of the second tube;

- The spring is an extendable spring, for example with a garter threaded directly onto the second portion and the dimensions of the chamber are sufficient to allow the extension of the spring by means of a tool, so that the spring can slide over it. the projection for the withdrawal of the end of the end piece from the bore; - The spring includes damping means limiting the disconnection of said spring by the tool, preventing the release of the spring in the sealing position when the tube is under pressure;

the damping means consist of a colored washer of semi-rigid material of hardness between 30 shores and 80 shores, for example 65 shores, fixed to the spring and of dimension arranged on the one hand to pass into the chamber and other part to project beyond the chamber in the locked position.

Such an arrangement makes it possible to visually check whether the spring is indeed in the locked position and whether the connection is therefore made completely and tightly. the tool is a rigid ring, sliding axially, fixedly installed on the tube end piece; the seal is formed by a ring of rigid material in the form of a cylindrical sleeve threaded with friction on the first portion, provided in its longitudinal extension with a ring of elastomeric material suitable for sealing, said ring being of external surface able to cooperate with gentle friction with the internal face of the bore; the ring is integral with the ring of elastomeric material; - The junction face of the ring with the ring is of complementary shape with that of the ring, for example straight;

- the ring of elastomeric material is substantially in the form of an elongated 8; - The ring has an end portion in annular cylindrical portions, arranged angularly around the axis of the joint, and cooperating with the internal face of the ring; the connector comprises two rings of elastomeric material, located respectively on either side of the ring; the connector comprises two rings made of rigid material;

- The rings are connected together by one of said rings of elastomeric material of which they are integral, at least one of said rings comprising the other ring of elastomeric material at its other end.

The present invention will be better understood on reading the following description of the embodiments given below without implied limitation. It refers to the accompanying drawings in which:

- Figure 1 is an axial sectional view of the connector according to a first embodiment of the invention, between a part and a tube ready to be disconnected 1 'from one another. - Figure 2 is an axial sectional view of the connector according to a second embodiment of the invention between two tubes in the locked position relative to one another.

- Figure 3 is a schematic view in axial section of the connection between two tubes as shown in Figure 2 before connection, also dynamically showing the successive positions of the spring during connection. Figures 4 and 5 are views in partial longitudinal section of two variants of another embodiment according to the invention, with damping means, also arranged to serve as a visual indicator.

- Figure 6 is a sectional view of an embodiment of a composite joint usable according to the invention.

- Figure 7 is a tube tip according to the embodiment of Figures 4 and 5, taken out of the part, showing the spring with damping means in position before connection.

- Figure 8 is a side view, by the edge, of the spring of Figures 4, 5 and 7 with damping means.

Figures 1 and 2 show a sealed connection 1 between a nozzle 2 of tube 3, rigid, for example aluminum, inserted in a cylindrical bore 4 formed in a part 5 for example steel (Figure 1), or formed by a second tube 6, for example made of aluminum (see then Figure 2).

In the following description, the same reference numbers are used to designate the same elements. The part can for example be a compressor block, a pressure reducer, a condenser or even an intermediate flange screwed beforehand on the block. The part is generally provided with a flat face 7, facing outwards and into which opens the bore 4.

The end piece 2, for example obtained by rolling or machining, comprises a first cylindrical end portion 8, ending in a flaring 9 which opens onto the bore 10 situated in the extension of the connection bore 4, and whose diameter is for example identical or substantially identical to the internal diameter of the end piece 2, which virtually eliminates any pressure drop due to the connector.

In the embodiment more particularly described here, the first portion is provided with a composite seal 11 constituted by two steel or rigid plastic rings 12 and 13 forming a sleeve threaded by friction or by force on the first portion 8, and two rings 14 and 15 of elastomeric material, for example of elastomer with butyl chain or HNBR, one of the rings 14 being located between, and fixed on, the two rings and the other 15 being fixed on the end of the ring 13 located on the side of the nozzle, remote from the outlet of the fluid.

The rings of rigid material 12 and 13 in the form of a cylindrical sleeve, that is to say constituted by cylinders of height greater than their thickness, for example between 1.5 times and 5 times said thickness, for example of the order twice or three times greater, are therefore located in the longitudinal extension of the rings which are, at the free state, of thickness greater than the thickness of the sleeve.

The end of the ring 12 is for example of partially annular shape, or more generally of shape complementary to that of the ring 14 to partially match the shape of the outer wall of said ring.

In one embodiment, the external wall of junction with the ring is for example straight, that is to say perpendicular to the axis of the ring.

The rings 12 and 13 are here fixedly fixed to the rings, for example by gluing, overmolding or vulcanization during the manufacture of the seal, in the longitudinal extension of the rings. The rings 12 and 13 have a cylindrical internal surface cooperating with friction with the external surface of the tube end piece and an external surface capable of cooperating with gentle friction with the internal face of connection bore. By soft friction means compliance with dimensional tolerances between the bore and the ring arranged so that the distance between their two facing surfaces is between 0.05 mm and 0.22 mm. The axes of the rings in the shape of an O-ring and of the rings coincide with the axis of the tube on the end piece of which the composite seal is threaded. The elastomeric material can be replaced by an equivalent material as long as it has good elasticity.

The rings, of constant section, extend for example on either side of the internal and external faces of the rings or are substantially tangent to the longitudinal extension of the internal faces of the rings, and are projecting in the free state, for example a few tenths of a millimeter, relative to the outer face of the rings.

The rings can, for their part, be rings made of aluminum, steel, galvanized steel or other rigid material (in plastic material for example) with an adjustment tolerance of the H7g6 type, taking bore 4 as a base, for example of nominal diameter 12 mm; 15.3 mm; 18.2 mm or 21.4 mm.

The rings 12 and 13 are for example of identical dimensions. One of the rings can also be smaller than the other, for example having a height equal to 2/3 of the height of the other ring.

The end piece 2 comprises a second portion 16 at least partially inside the bore, separated from the first portion 8 by a fold 17 which blocks the seal 11 on one side in an axial position, the other side being axially locked, advantageously with a certain axial clearance, by the flare 9. The second portion 16 comprises a sleeve 18 comprising a first portion 19, of end, cylindrical with a first radial thickness Ç} Q relative to the external face of the nozzle, a second portion in the form of a frustoconical blank in a gentle slope towards the outside of the end piece in the direction opposite to the fold 17, to form the radial projection 20, of maximum radial thickness h. relative to the outer face of the tube end piece. The projection 20 has for example a flat top 21 over a length, for example of a few millimeters. On the other side and opposite to the first portion, the projection 20 has a frustoconical blank 22 inclined towards the tube end piece in the direction opposite to said first portion, forming an external angle α of between 100 ° and 160 °, for example 135. The blank is extended in the lower part by a third cylindrical end part of radial thickness d. _A relative to the external face of the end piece less than the height of the fold 17, with d. _A greater than d. _£ -

A second fold 24, for example identical to fold 17 and entirely located outside the bore, allows the sleeve to be fixed and axially locked between the two folds.

The projection 20 can also be formed monolithically with the tube and not by an attached sleeve. In the embodiment of FIG. 1, the connector 1 comprises a substantially annular chamber 25, obtained by recess produced in the face 7 of the part 5. The chamber 25 is provided on one side with an internal radial face 25 ' stop for example perpendicular to the axis of the bore, on the side of the chamber distant from said axis.

The chamber 25 extends the bore 4 and extends radially opposite the projection 20 over a distance d. relative to the apex 21 also releasing a volume v above the projection substantially symmetrical with respect to the median height of said projection, over a distance of. parallel to the axis of the nozzle, that is to say in the direction perpendicular to said height with çV_ ≥ d ,.

The chamber 25 is delimited in the direction opposite to the bore 4, by the internal face 26 'of a lip 26 forming a flange, the edge 27 of which is radially situated at a distance d' from the external face of the second portion , in this case constituted in the embodiment more particularly described here by the external face 28 of the sleeve 18, d '' + 4ι being a little greater than the maximum radial thickness or height h of the projection 20, for example of one to two mm.

More precisely, the internal face 26 ′ of the lip 26 is inclined at an angle with the axis 30 of the end piece equal to or substantially equal to the angle α, the face of the blank 22 and the face 26 ′ therefore being parallel or substantially parallel to one another.

The connector also comprises an annular spring 31, of constant cylindrical section, metallic, extensible, of the garter type, threaded beforehand by force on the end piece to come in sealed locking position 32 in the obtuse angle of the blank 22 when the connection is made. The diameter r of the spring 31 is such that r + do <d '' + d ₁ r <or ≈ d and r> d '' Furthermore, the bore 4 is of diameter D, and the external diameter of the second portion of the end-piece provided with the sleeve at the level of the first part 19 being D ′, we also have:

D - D

<r

for example :

D - D _ r 2 2

Thus, the tube end piece can be introduced into the bore, the spring standing around the first part 19 which allows it to pass under the lip.

26, then after movement of the spring which abuts on the radial internal face 25 ′ of the chamber, the latter is pushed back above the projection 22 in the chamber 25, then abruptly descends into the blocking position 32 of the spring between the inclined faces of the blank 22 and the internal face of the lip 26. In another embodiment such as shown in Figure 2, the chamber is constituted by a cage 33, mounted externally on the end of the second tube 6 in the extension of the bore 4 The cage is composed of a radial base 34, pierced with an orifice central cylindrical allowing the tube end piece to pass, base on which the end of the second tube is fixed, for example by means of two plies 35 and 36 which wedge the radial base between them.

The outer ply 36 then has the abutment face 36 'which will allow the spring to be pushed back just like the face 25' described above.

The cage comprises on the other side a curved wall 37 delimiting the annular chamber, which ends in the lip or flange 38 in the form of a frustoconical blank inclined towards the end of the tube and the end of which is situated at a certain radial distance. d 'of the surface 28 of the second portion in this case constituted by the external face of the sleeve portion 23.

Here again the tube end piece 2 is telescopically fitted into the bore 4 as we have just seen, the circular spring placed in the cage or the chamber being interposed between the end 38 ′ of the lip 38 and the blank 22 of the projection 21, to prevent the relative telescopic release of the endpiece relative to the chamber, the set of seals or the seal 11 allowing '' prevent leaks.

Taking into account the arrangement of the various elements of the fitting, the pressure in the circuit exerts a force on the rings 14 and 15, amplified by the intermediate rings 12 and 13, for example sliding ones, coming to supplement and optimize the compression force of the joints. in proportion to the pressure exerted.

In the embodiment more particularly described here, the connector further comprises a tool 39 consisting of a rigid ring sliding axially between a first rest position where the connection is made in leaktight manner, and a second position for releasing the connector. The rigid ring is also fixedly installed on one end of the tube.

More specifically, the tool 39 comprises a cylindrical body 40, the internal diameter of which exceeds the external diameter of the fold 24. The body 40 has at one end a base wall 41 pierced with an opening 42, through which the end piece passes of tube 2 and at the other end an end plate 43 pierced with a passage opening for the endpiece and integral with the body 40 consisting of a single piece.

This body can also consist of two symmetrical half-sections, mounted, pivoting around a common pivot (not shown) at one of their ends.

The connection and disconnection method will now be described in more detail with reference to FIG. 3. The spring is first of all in position 50 which will allow the insertion of the end piece into the bore.

When the end piece is pressed longitudinally to make it penetrate into the bore, the spring then passes below the lip 38 and comes partially into abutment on the abutment face 36 'of the chamber 25 formed by the cage 33.

The pressure continuing to be exerted to join the nozzle to the bore, the spring slides along the inclined face of the projection 20 until it reaches position 51 where the spring is located above the flat 21, occupying then at least in part the volume of the chamber situated above said projection, then the spring by elasticity suddenly takes its blocking position 52, for locking the connection in the lower part of the blank 22.

The spring 31 is then wedged between the projection and the lip 38. When it is desired to disconnect the snap connection, which it is preferable to do after decompression of the gas circuit, for example of Freon, the tool 39 is pushed along arrow 53, this causes the extension of the circular spring, pushed back above the flat 22, which rolls up to position 50 when the tip is continued to be extracted, and abuts on the projection 17, of sufficient height It is then possible to pull the tip completely along its axis to extract it entirely from the bore, the spring passing under the lip 38.

We will now describe another embodiment of the connector according to the invention with reference to FIGS. 4 and 5.

The same reference numbers will be used to designate the same elements as those described with reference to Figures 1 and 2. Figure 4 shows a sealed connection 60 between a nozzle 2 of rigid tube 3 inserted in a cylindrical bore 4 formed in a part 5 (Figure 4), or even formed by a second tube 6 (Figure 5).

The end piece comprises a first cylindrical end portion 8 provided with a seal 61 which will be described with reference to FIG. 6.

As described with reference to FIGS. 1 and 2, the end piece 2 also comprises a second portion 16 separated from the rest of the tube 2 by folds 17 and 24, the fold 17 blocking the seal 61 on one side in the axial position.

This second portion 16 comprises a sleeve 18 provided with a radial projection 20 comprising two frustoconical fronts inclined towards the end of the tube.

In the embodiment of FIG. 4, the connector 60 comprises a substantially annular chamber 25 obtained by means of two attached parts 62 and 63. The part 62 for example made of plastic material is annular around the bore.

It abuts against the external face 7 of the part 5 and fits into the part 63 also annular, the internal faces of the part 63 and the external face directed towards the tube of the annular part 62 forming said chamber 25.

The chamber 25 is therefore, similarly to what has been described with reference to FIG. 1, delimited in the direction opposite to the bore by the internal face 26 ′ of a lip 26 forming a flange whose edge will allow 1 self-locking of the spring 31.

FIG. 5 shows an embodiment similar to that of FIG. 2, the chamber 25 being this time constituted by an attached part formed by a cage 33, constituted by a ring of substantially semi-cylindrical cross section.

In the embodiments of Figures 4 and 5 the spring is also provided on its external face located on the side of the tube of damping means also forming a visual indicator.

The means are for example constituted by a washer 65 made of fluorescent plastic material and / or of bright color.

The washer is integral with the spring on its face situated on the side of the end piece of said tube, for example by vulcanization or overmolding.

The length L (see FIG. 8) of the washer and the stiffness of the material are arranged so as not to bend, for example, under a thrust of the order of 4 daN, which allows disconnection when the tube is not under pressure thanks with the tool, and to bend under a pressure of the order of lOdaN, thus playing a role of shock absorber avoiding disconnection when the tube is under pressure (a few bars for example).

As shown in Figures 4 and 5, when the spring abuts against the inner face of the lips 26 and / or 38, the washer 65 is located entirely outside of said lip and thus makes it possible to visually check that the spring is well in abutment.

The part 43 allows when it comes under pressure on the opposite face of the washer 65, to push the spring or to let it resume its blocking position as indicated with reference to the other figures.

The junction between the washer 65 and the spring 31 is flexible and allows articulation, the thickness of the washer 65 being moreover less than the distance existing between the lip and the upper face of the sleeve so that when this part is pushed back the visual indicator can penetrate inside the chamber 25.

FIG. 6 shows a particularly advantageous embodiment of seal 61 which can be used with the connector according to the invention.

It allows improved sealing. The seal 61 comprises a ring 66 of elastomeric material formed in part by a double O-ring substantially in the shape of 8 elongated parallel to the axis 67 of the seal.

More generally, the ring 66 comprises on the same side of the joint with respect to the axis 67, two lines or sealing or pressure surfaces, respectively, 68 and 69, located in pairs in the same cylindrical plane of axis 67 and formed by the bulged portions of 8. The ring 66 is arranged to cooperate on the one hand with the external face of the end piece and on the other hand with the internal face of the part.

The ring 66 further comprises an end portion 70 for frictionally blocking the seal on the end piece, for example constituted by portions 71 of thin cylinder arranged angularly, for example six portions in the form of strips parallel to, and located on the side of, the axis 67 being inscribed in an annular cylinder and attached by one end to the lower face 72 of the part 8 of the ring with which they are integral.

The seal 61 also includes a ring 73 of rigid material, in the form of a cylindrical sleeve, of the type described with reference to FIG. 1, and the end 74 of junction of which with the part in the form of

8 of the ring is for example straight.

The external surface 75 of the ring is arranged to cooperate with gentle friction with the internal face of the bore drilled in the part 5 and its internal face cooperates with the external faces of the portions 71 in the form of strips, the internal faces of which come from them. - even cooperate with friction with the end of the tube.

The portions extend for example over the entire height of the ring 73 and in arcs of a circle between 5 ° and 50 °, for example 10 °.

The angular distribution of the portions 71 is symmetrical with respect to the axis, and varies according to the number of portions which can be between two and twenty, for example three, four, six or eight.

The thickness of the portions 71 in the form of strips is for example between 0.3 mm and 2 mm, for example 0.5 even.

FIG. 7 shows the tube end piece of FIG. 4, the spring 31 of which is passed on the other side of the projection 20, the washer 65 coming to bear on the gentle slope of the blank, over substantially its entire length.

As is obvious and as it follows from the above, the present invention is not limited to the embodiments more particularly described.

On the contrary, it embraces all the variants and in particular those where the tool is removable and / or the seal 11 is different, for example consisting of a single lateral ring with a single ring, and / or the case where the spring is constituted by a split ring of rigid plastic material (in the case of less pressure), or even the case where the tube end piece comprises a second part in a single piece whose external face has said projection.

Claims

1. Tight fitting (1) comprising a rigid tube end (2) (3) inserted into a cylindrical bore (4) formed in a part (5) or by a second tube (6), the rigid tube end comprising a first end portion (8), provided with at least one seal (11) between the internal face of the bore and the external face of said first portion of the tube end piece, characterized in that that said tube end piece comprises a second portion (16) at least partially inside the bore having radially on its periphery a projection (20) with frustoconical blanks, in that the bore (4) is terminated by room

(25) substantially annular extending radially outward opposite the projection (20) with frustoconical blanks, terminated on one side by an internal radial locking face and on the other side directed towards the end of the part or towards the outside of the second tube by a retaining lip (26, 38) whose edge is radially situated at a distance from the external face of the second portion slightly greater than the height of said projection and in this that it comprises a circular spring (31) threaded on said second portion (16), interposed between the projection (20) and the internal face of the lip (26, 38) to prevent the relative telescopic release of the end piece (2) tube and bore (4).

2. Connection according to claim 1, characterized in that the second portion (16) comprises a sleeve (18) forming said projection, threaded and fixed on one end of tube.

3. Connection according to any one of the preceding claims, characterized in that the second portion (16) of the tube end-piece is delimited with respect to the first portion (8) of the tube by a first fold (17) of the wall of said tube end piece, extending radially, projecting towards the outside of the end piece and inside the bore.

4. Connection according to claim 3 dependent on claim 2, characterized in that the end piece (2) of rigid tube comprises a second ply (24) extending radially, projecting outwardly from said end piece, located at distance from the first ply, on the side opposite the end of said tip, said plies forming longitudinal locking stops on either side of the sleeve (18) threaded on said tip.

5. Connection according to claim 1, characterized in that the second portion is formed in one piece with the first portion of the rigid tube end piece.

6. Connection between a tube end piece and a second tube according to any one of the preceding claims, characterized in that the chamber (25) is constituted by an end cage (33) attached, fixed irremovably on the end of the second tube.

7. Connection according to any one of the preceding claims, characterized in that the spring (31) is an extendable spring threaded directly onto the second portion (16) and the dimensions of the chamber (25) are sufficient to allow extension of the spring by means of a tool (39), so that the spring can slide over the projection (20) in order to withdraw the end of the end piece (2) out of the bore (4) .

8. Connection according to claim 7, characterized in that the spring comprises damping means limiting the disconnection of the spring by the tool.

9. A connector according to claim 8, characterized in that the damping means consist of a colored washer of semi-rigid material, fixed to the spring and of sufficient size to protrude beyond the chamber in the locked position.

10. A connector according to claim 6, characterized in that the tool (39) is a rigid ring, sliding axially, fixedly installed on one end of the tube.

11. Connection according to any one of the preceding claims, characterized in that the tight seal (11) is formed by at least one ring

(12, 13) of rigid material in the form of a cylindrical sleeve threaded with friction on the first portion (8), provided in its longitudinal extension at least one ring (14, 15) of elastomeric material capable of sealing, said ring being of external surface capable of cooperating with gentle friction with the internal face of the bore.

12. Connection according to claim 8, characterized in that the ring (12, 13) is integral with the ring (14, 15) made of elastomeric material.

13. Connection according to any one of claims 8 and 9, characterized in that the ring (61) of elastomeric material, is substantially in the form of an elongated 8.

14. Connection according to any one of the preceding claims, characterized in that the ring comprises an end portion in annular cylindrical portions, arranged angularly around the axis of the joint, and cooperating with the internal face of the ring.