A motor vehicle door with a side-reinforcing bar

Abstract: A motor vehicle door with a side-reinforcing bar which includes a frame (3), static connection means (20, 22) for fixing the bar (18) to the frame (3) when it is in an undeformed rest configuration, and dynamic connection means (27, 28) for fixing the bar (18) to the frame (3) when the bar is forced into an active configuration in which it is bent as a result of stress from outside the motor vehicle. The dynamic connection means (27, 28) for the bar (18) are independent of the static connection means (20, 22) and include engagement means (28) interposed between each end portion (18a, 18b) of the bar (18) and respective seats (27) in the frame (3), operable to secure the end portions (18a, 18b) of the bar (18) to the frame (3) should the bar (18) bend into its active configuration, thereby causing the bar (18) to generate traction on the frame (3) in correspondence with the said seats (27).

Description: The present invention relates to a motor vehicle door with a side-reinforcing bar, including a frame, static connection means for connecting the bar to the frame in its undeformed, rest condition, and dynamic connection means for connecting the bar to the frame should it be in an active condition, in which it is bent as a result of stress from outside the vehicle. In prior art doors of this type, the side-reinforcing bar is generally fixed to the frame by welding or by known connection means which are responsible both for holding the bar adjacent the frame in its undeformed condition and for securing it to the frame when it is deformed as a result of external stress transmitted to the frame, typically caused by a body hitting the door. Generally speaking, known means for fixing the bar ensure both the static connection and the dynamic connection of the bar. In this situation, the fixing means must be constructed so as to provide a compromise able to ensure both static connection and dynamic connection, thereby generally increasing both weight and manufacturing costs and thus the production cost of the whole door. This problem is not too acute when the bar and the frame are made of the same weldable material, such as steel plate, and are fixed together in a welding operation simultaneously providing both static connection and dynamic connection. However, if the materials constituting the bar and the frame cannot be welded easily, or at all, and must therefore be provided with other connection means, for example fixing screws, additional mechanical work must be carried out and additional connection means must be used, which need to be big enough to resist stress resulting from deformation of the bar and are thus relatively complex, heavy and expensive to manufacture. US-A-5 544 930 discloses a motor vehicle door with a side-reinforcing bar having the features defined in the preamble of Claim 1. In order to overcome the above disadvantages, the present invention provides a vehicle door as defined in the appended claims. Thanks to the arrangement of the invention, the static and dynamic connection means of the bar are essentially independent of each other, so that they can be individually optimised to perform their function most effectively. This makes it possible to form the means for fixing the bar to the frame to be simpler, lighter and more economical than known means which are responsible for both static and dynamic connection of the bar, and also make it easier to fit the bar onto the frame. In particular, the dynamic connection means for the bar are constituted by members operable to force fit into seats in the frame should the bar bend, without there being any need for screw means. Further characteristics and advantages of the invention will become apparent from the detailed description which follows, provided purely by way of non-limitative example, with reference to the appended drawings, in which: Figure 1 is an elevational schematic side view from inside the door of the invention fitted with a side-reinforcing bar; Figure 2 is an elevational sectioned view taken on the line II-II of Figure 1, Figures 3 and 4 are similar elevational sectioned views taken on the lines III-III and IV-IV respectively of Figure 1; and Figure 5 is a schematic perspective view of an end portion of a side-reinforcing bar according to a variant of the invention. With reference to the drawings, a motor vehicle door is generally indicated 1, specifically a front right hand door. The door 1 includes a frame 3 of a light alloy, preferably a magnesium-based alloy, and shaped like a half-shell. It includes a front upright 5 and a rear upright 7 which are substantially parallel and rigidly connected at their upper and lower portions by means of a pair of cross members 9 and 11, respectively upper and lower. The casting of the frame 3 is formed by hot forming the light alloy of which it is made, typically in a die-casting operation whereby the molten alloy is poured under pressure into a die, or in a thixoforming operation whereby light-alloy elements are heated to a plastic consistency and then compressed into a mould, causing the elements, in particular the uprights 5, 7 and the cross members 9, 11 to be formed in one piece. The frame 3 is adapted to have a skin panel 13 fitted to its outer surface, with reference to the door once fitted onto the relevant motor vehicle, the skin panel 13 preferably being constituted by a sheet of plastics material or by sheet metal, aluminium for example. During the casting of the frame 3, a pair of seats 14, 15 are conveniently formed near the uprights 5 and 7 for engagement by respective end portions 18a, 18b of a side-reinforcing bar 18 for the door 1, arranged transverse the uprights 5 and 7. The bar 18 comprises an elongate structural, conveniently of aluminium, having a cross section substantially the shape of an 8, so that it forms an intermediate longitudinal reinforcement rib 19. Having been brought up to the frame 3 in a direction substantially perpendicular to the overall plane thereof, the bar is coupled to the frame so that its end portions 18a, 18b fit into a pair of fork-like formations 20 formed in one piece with the frame 3. Each formation 20 includes a pair of parallel arms 20a and 20b, upper and lower respectively, which project from the frame 3 perpendicular to the general plane thereof. A layer of adhesive material, of a known semi-structural type, for example, is interposed between the arms 20a and 20b and the corresponding portions 18a, 18b of the bar 18, so as to form a static connection between the bar 18 and the frame 3. A transverse plate 24, also conveniently of aluminium and slightly larger than the cross section of the bar 18, is fixed flat to each end 18a, 18b thereof, in such a way that an edge of each plate 24 extends beyond the section of each bar 18. Each protruding edge constitutes a retainer tongue 28 for insertion, when the bar 18 is fitted, into a corresponding elongate cavity 27 adjacent a seat 25 for housing an associated plate 24. When the bar 18 is not deformed, the retainer tongues 28 are positioned in the cavities 27, possibly with some clearance. They form a very simple and economical structure which provides, however, a highly reliable means of dynamic connection for the bar 18, should this bend as a result of an external impact, in which case the retainer tongues 28 would be forced into the cavities 27 in the manner of a hook, transmitting the stress from the bar 18 to the frame 3, in such a way that the frame 3 can cooperate with the bar 18 to resist the applied stress. In this condition, the fact that the adhesive material 22 interposed between the fork-like formations 20 and the bar 18 could give way does not affect the reliability of the dynamic connection provided by the retainer tongues 28 and the cavities 27, so that the static connection means of the bar 18 can be simple and inexpensive, since they need only withstand weak stress. For preference, each plate 24 has an auxiliary edge, or a pair of auxiliary edges extending beyond the cross section of the bar 18 along a direction transverse the retainer tongues 28, thus constituting respective auxiliary gripping tongues 30 (see figure 5). In this case, it is convenient if the formations 20 are positioned and shaped in such a way that the sides 32 of the arms 20a, 20b of each fork-like formation 20 facing the nearest plate 24 act as shoulders against which the gripping tongues 30 abut if the bar 18 is forced to bend, thereby increasing the surface involved in the coupling action of the end portions 18a, 18b of the bar 18 with respect to the seats 14 and 15 of the frame 3.

Claims: A motor vehicle door with a side-reinforcing bar (18), the door including: a frame (3), static connection means (20, 22) for fixing the bar (18) to the frame (3) when it is in an undeformed rest configuration, and dynamic connection means (27, 28) for securing the bar (18) to the frame (3) upon reaching its active configuration, in which it is bent as a result of a force being applied to the motor vehicle from outside, the dynamic connection means (27, 28) of the bar (18) being independent of the static connection means (20, 22) and including engagement means (28), interposed between each end portion (18a, 18b) of the bar (18) and respective seats (27) adapted to couple the end portions (18a, 18b) of the bar (18) to the frame (3) in the event of the bar (18) being forced into its active configuration, so as to exert, by means of the bar (18), a traction on the frame (3), the traction being applied at the seats (27), characterised in that the seats (27) for coupling the end portions (18a, 18b) of the bar (18) to the frame (3) are cavities formed in the frame (3) of the door (1), and that the static connection (20, 22) means include engagement means (20) formed in one piece with the casting of the frame (3) during the forming process thereof. A door according to Claim 1, characterised in that the said engagement means (28) are fixed to the end portions (18a, 18b) of the bar (18). A door according to Claim 1 or Claim 2, characterised in that the frame (3) is made of a light alloy, in particular a magnesium alloy. A door according to any one of Clams 1 to 3, characterised in that each seat includes an elongate slot (27) transverse the bar (18) and substantially parallel to a general plane of the frame (3), and is provided for engagement by a tongue (28) projecting from an end portion (18a, 18b) of the reinforcing bar (18). A door according to claim 4, characterised in that each tongue (28) is an edge portion of an end body (24) fixed flat to an end (18a, 18b) of the bar (18). A door according to Claim 4 or Claim 5, characterised in that each of the engagement formations (20) is configured like a fork and is arranged near a corresponding seat (27), the fork-like formations (20) being able to receive the bar (18) inserted in a movement substantially perpendicular to the overall plane of the frame (3). A door according to Claim 6, characterised in that the end portions (18a, 18b) of the bar (18) have auxiliary gripping means (30) for abutting against respective shoulders (32) of the said fork-like formations (20) when the bar (18) bends to a particular extent. A door according to Claim 7, characterised in that the auxiliary gripping means are constituted by edges (30) of the said end bodies (24) of the bar (18), which extend transverse the said tongue (28).

Inventors: COPPERO ELIO, MOLINA GIUSEPPE, COPPERO. ELIO, MOLINA, GIUSEPPE
Applicants: COMAU SPA
Application year: 2001
Main classification: B60J5
IPC codes: B60J5