TECHNICAL FIELD

The present invention relates to a connection for tubes of a motor vehicle, in particular to a connection for tubes of a heat exchanger in a conditioning system of a motor vehicle.

The conditioning system of a motor vehicle needs, for its duty cycle, to cool an operating fluid of the system, and heat exchangers are usually used for this purpose.

BACKGROUND ART

It is known to use heat exchangers comprising two coaxial tubes, one in which the operating fluid of the conditioning system flows, preferably in the gaseous sate, and an outer tube, in which a coolant fluid for the operating fluid flows around the inner tube, preferably the same operating fluid in the liquid state . Heat exchangers of the known art also comprise a connector implemented by means of a hose fitted on the inner tube and comprising an opening designed to fit on the outer tube. The hose usually comprises an opening perpendicular to the axis of the heat exchanger inside which a tube is engaged, or welded, which allows passage of the coolant fluid.

Heat exchangers of the known art therefore need a spacious housing as the flow tube of the coolant fluid occupies considerable space in the direction perpendicular to the axis of the heat exchanger.

The need is therefore felt to have a connection for tubes of a heat exchanger of a conditioning circuit for motor vehicles that is compact and more versatile.

The need is also felt to have a connection that can be manufactured in a simple, rapid and inexpensive manner.

DISCLOSURE OF INVENTION

The object of the present invention is to provide a connection that enables overcoming the above-described technical problems.

The aforesaid object is achieved by a connection according to claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, a preferred embodiment is described below, by way of non-limitative example, and with reference to the accompanying drawings, in which:

Figure 1 is a sectional view of a heat exchanger comprising a connection according to the invention;

Figure 2 is a section along line II-II of the heat exchanger in Figure 1; and

Figure 3 is a lateral view of the heat exchanger in Figure

1.

BEST MODE FOR CARRYING OUT THE INVENTION

Figure 1 shows a heat exchanger 1 of a conditioning system for a motor vehicle. The heat exchanger 1 comprises an inner tube 2 with an axis A and in which an operating fluid of the conditioning system flows, preferably in the gaseous state, and an outer tube 3 coaxial to the inner tube 2 inside which a coolant fluid for the operating fluid flows, this coolant preferably being the same operating fluid that flows in the inner tube 2, but in the liquid state.

The inner tube 2 is made of a metal material, preferably aluminium or one of its alloys, and has a constant, preferably circular, section along axis A. The outer tube 3 is made of a metal material, preferably aluminium or one of its alloys, and comprises a portion 6 coaxial to and with a constant section along axis A, preferably with a circular section of larger diameter than the inner tube 1, and a mechanically worked deformed portion 7. Portion 6 and the inner tube 2 define a cylindrical annular chamber 8 radially delimited by the inner radial surface 6a of portion 6 and by the outer radial surface 2a of the inner tube 2, and axially delimited by the ends of portion 6. Portion 7 is mechanically cold deformed and comprises a staggered portion 9, offset in a direction perpendicular to axis A and radially tapering until its end couples with the outer surface 2a of the inner tube 2. Portion 7 further comprises a projection 11 extending radially in a direction perpendicular to axis A and connected to the staggered portion 9. The projection 11 (Figure 2) has a profile 11a with a substantially overturned U shape and connected to the staggered portion 9.

The staggered portion 9 defines a chamber 12 around the inner tube 2 communicating with the annular chamber 8 while the projection 11 defines an inlet 13 communicating with chamber 12. The heat exchanger 1 comprises a coolant fluid circulation tube 10 made of a metal material, preferably aluminium or one of its alloys, comprising a deformed portion 14 designed to be inserted in the inlet 13 and an inclined portion 15 connected to the deformed portion 14.

The inclined portion 15 is inclined at an angle a with respect to axis A and has a constant section along its axis, preferably a circular section. The angle a preferably has a value comprised between 10° and 180°, even more preferably between 25° and 45°.

The deformed portion 14 has its axis parallel to axis A and is connected to the inclined portion 15. The section of the deformed portion 14 is complementary to that of the projection 11 at one end and tapered to connect with the inclined portion 15. The tube 10 is fixed to the projection 11 by means of braze welding onto the inlet profile thereof, in the projection 11 and the inner tube 2 is welded inside the outer tube 3, preferably all together in a single welding operation, preferably by braze welding .

The weld metal of the braze welding is a metal material, preferably an aluminium alloy.

The outer tube 3 may also comprise a plurality of channels 16 defined by a plurality of ribs 17 extending radially towards the inner tube 2 from the radial wall 6a and developing axially between the ends of portion 6 of the outer tube 2. The channels 16 are configured to increase the heat-exchange surface of the coolant fluid.

During manufacture, in order to obtain the staggered portion 9 and the projection 11 of the outer tube 3 it is necessary to mechanically remove or radially deform the ribs 17 for an axial depth of less than 50 mm, preferably 25-35 mm.

In use, the coolant fluid flows in the channels 16, passing into the staggered portion and conveyed from there into the tube 10. If necessary, the flow can be in the opposite direction.

During its passage, the coolant fluid absorbs the heat of the operating fluid that flows inside the inner tube 2 and which is thus cooled.

From the foregoing, the advantages of a connection according to the invention are evident. The use of an inclined tube 10 welded directly on a projection 11 made on the outer tube 3 enables not using hoses of the known art, with a reduction in the space occupied, savings on materials and easy installation.

The braze welding permits achieving a tight seal between the three assembled tubes and considerable solidity.

The inclination of the inclined portion 15 of the tube 10 could be varied according to design, thus obtaining a highly versatile heat exchanger 1 with regard to its positioning.

Finally, it is clear that modifications and variants can be made regarding the heat exchanger 1 made according to the present invention without departing from the scope of the claims.

By way of example, the ribs 17 and the associated channels might not be present or there could be other embodiments designed to increase the heat exchange between the two fluids.