Pipe joints or couplings – Packed – Flanged pipe
Reexamination Certificate
2000-10-10
2002-06-04
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Packed
Flanged pipe
C285S337000, C285S374000
Reexamination Certificate
active
06398269
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a tube connection between a collector of a motor vehicle heat exchanger and a line that feeds the inner heat exchange fluid to the collector or delivers it from the collector, having the further features according to the preamble of claim
1
. Such a tube connection corresponds to the internal prior art of the Applicant Company.
BACKGROUND OF THE INVENTION
The invention further relates to a novel method, having the features of claim
14
, for the production of such a tube connection.
According to said internal prior art of the Applicant Company, it is customary to use an O-ring as a seal between a connecting sleeve on the collector and the line. Such an O-ring is firstly fitted onto the free end of the line and is then pressed with the latter into the wide cross section, remote from the collector, between the line and the connecting sleeve, in the ideal case with an outer flange of the connecting sleeve abutting against an outer bead of the line as the O-ring is pressed flat to the dimension of the wide cross section remote from the collector. In unfavorable cases, however, a section of the O-ring becomes partly caught in the intermediate space between the outer flange and the outer bead. This leads to premature damage to the O-ring, which in itself causes sealing problems because the actual sealing function of the O-ring becomes impaired. If the O-ring is not fitted optimally, or even merely because of its tolerances, it is not uncommon for sticking to actually occur when the connecting sleeve and the line are being slid together, merely because of the undesirably deformed O-ring, so that the tube connection does not always reliably take up its intended final position. This function is further compromised by the fact that the O-ring is intended to be guided on the inner surface of the connecting sleeve into the wide cross section remote from the collector, but the transition from this inner surface into the outer flange often has an unfavorable curvature, owing to tolerances, and the inner surface is further often modified by lateral spreading of a flux to such an extent as to impair the friction. When the O-ring is slid onto the free end of the line, it is also possible for the O-ring to suffer undesired twisting and turning, although in the ideal case it is supported from the rear of the outer bead. Such negative effects can only be overcome to some extent if a high fitting force is applied; however, this still leaves the risk of undesired deformation of the O-ring and of deformed regions of the O-ring entering the space between the outer bead and the outer flange. The difficulties of the known method are further exacerbated by the fact that, during the final assembly of the tube connection, the connection clips, which are customarily used for the final clamping of the outer flange and the outer bead together with the O-ring in between, can only be mounted, by gripping the outer flange and the outer bead, if the outer flange and the outer bead bear tightly on one another and are not forcibly spaced apart somewhat by extraneous inserted parts such as sections of the unintentionally deformed O-ring. This leads to a recognizable unsuccessful tube connection, which is discarded as a reject. But even if the outer flange and the outer bead do achieve the desired tight connection, this tight connection still always needs to be maintained using separate means while the connection clips are being mounted. In the case of manual assembly, as is customary in repair and servicing operations, for example, both hands are hence needed for mounting the clip, without for example having one hand still available to hold the tube or another aid, such as a pair of pliers or a lamp.
SUMMARY OF THE INVENTION
The object of the invention is hence to refine a tube connection of said type in such a way that it can be assembled easily and reliably, without the risk of incorrect connections, using only one hand or only one corresponding tool function, without having the tendency to come apart again by itself after assembly, but before a clamping device such as the connection clip etc. has yet been applied.
This object is achieved by all the features of claim
1
.
As is shown particularly clearly by the preferred production method according to claim
14
—with the expedient refinement according to claim
15
, the two features of which are preferably both implemented—the seal according to the invention is not fitted into the connecting sleeve on the free end of the tube connection, like the O-ring previously was, but in the internal cross section, here the wide cross section remote from the collector, inside the connecting sleeve on the collector. This has the advantage that, with this pre-assembly, a rough surface on the inside of the connecting sleeve or an unfavorable curvature geometry existing there no longer represents a problem for fitting the seal, since the pre-assembly is carried out still without compression. In the final state of the tube connection, a part of the seal, namely its sealing flange, is then intentionally clamped between the outer flange of the connecting sleeve and the outer bead of the line.
Since seals of the type in question here, whether they are O-ring seals or the form of the seal according to the invention, are made from relatively pressure-resistant elastomer material, the final state of the tube connection can, even while accommodating tolerances, be set up accurately by abutment of the sealing flange between the outer flange and the outer bead on their surfaces that face one another. Since, in this case, at least one sealing element, which is equivalent in its sealing action to an O-ring of normal design, is formed on the insertion sleeve of the seal, no functional disadvantage compared with the conventional sealing by an O-ring has to be tolerated in the case of the tube connection according to the invention, and moreover all said disadvantages can be avoided. This is particularly important because, in terms of their industrial production, that is to say when they are mass-produced articles, tube connections of the type in question here are arranged relatively inaccessibly in the foot space of motor vehicles.
In particular, special emphasis should further be placed on the following advantages: because the sealing element, which acts in the invention in similar fashion to the previous O-ring, is arranged on the insertion sleeve, the sealing element can no longer twist its cross section in the circumferential direction, as results in the case of the conventional O-ring with the creation of shear forces, which in turn lead to premature ageing. During the final assembly of the tube connection, which can be carried out with relatively small axial assembly forces, these assembly forces are also particularly small because, when the free end of the line is being inserted into the insertion sleeve and optionally the narrow cross section of the connecting sleeve next to the collector, the insertion sleeve can expand axially and is hence deformable in the direction of travel during the insertion movement, without experiencing a transverse extension that creates resistance as in the case of the known O-ring. What is particularly important is that, as early as during the pre-assembly, the sealing element replacing the O-ring is arranged at its definitive sealing location in the widened cross section between the connecting sleeve and the free tube end, and does not need to be pressed into this widened cross section only during the final assembly. Lastly, the tube connection according to the invention is also more reliable in terms of the risk that the incorporation of a seal might perhaps be forgotten during assembly. In the previously known case in which an O-ring seal is used, omission of the latter may nevertheless still lead to temporary purely metallic sealing between the outer flange of the connecting sleeve and the outer bead of the line, although this temporary metal seal cannot withstand continuous operation. In the case of th
Bochna David E.
Browne Lynne H.
Liniak Berenato Longacre & White
Valeo Klimatechnik GmbH & Co. KG
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