EP1931555A1

EP1931555A1 - Structural reinforcement for vehicles

Info

Publication number: EP1931555A1
Application number: EP05821841A
Authority: EP
Inventors: Jean Mendibourne; Jean-Jacques Undereiner; Frank Braymand; Gerald Bugli
Original assignee: L&L Products Inc
Current assignee: L&L Products Inc
Priority date: 2004-12-21
Filing date: 2005-12-21
Publication date: 2008-06-18
Also published as: RU2007127916A; GB0427839D0; GB2421478A; WO2006066966A1

Abstract

Structural reinforcement in vehicle structures is provided by inserted parts which are designed with at least two sections which provide different forms of reinforcement to provide reinforcement against two or more of front crash, side crash, rear crash, roll over and strength against noise, vibration and harshness.

Description

IMPROVEMENTS IN OR RELATING TO THE STRUCTURAL REINFORCEMENT

OF VEHICLES

The present invention relates to improvements in or relating to structural reinforcement in particular the structural reinforcement of vehicles. Although the present invention is described in relation to automotive vehicles the invention is equally applicable to provision of structural reinforcement in aircraft, marine and railroad transport.

Vehicles require reinforcement for a variety of reasons. For example, vehicles can be reinforced against impact such as in a crash. However, even in crash reinforcement a variety of types of reinforcement may be required, different reinforcement being required for front impact, side impact, rear impact and rollover crash. In addition vehicles need to be reinforced against regular noise, vibration and harshness during regular working

(sometimes known as NVH). The reinforcement needs to provide a combination of energy absorbing and energy dissipating functions depending upon the nature of the reinforcement required and the position in the vehicle that is to be reinforced.

Vehicle body shells are generally assembled from tubular structures generally metal structures consisting of longitudinal supporting structures, sometimes known as longits or rails. Transverse supporting structures of which there are usually at least three, front, middle and rear. Pillars for the doors and supporting the roof extending upwards from the longitudinal structures and frequently there are three pairs of pillars the A pillars at the front of the vehicle which pass upwards behind the engine compartment and contain the windscreen in its upper portion, the B pillars behind the front doors of the vehicle and the C pillars at the rear of the vehicle. Larger vehicles can have a larger number of pairs of pillars.

Different areas of the vehicle require reinforcement for different reasons. For example the front of the longitudinal section and the A pillars require reinforcement against front crash but they also require stabilisation to remove vibration and hardness of driving. The centre of the longitudinal structures and the B pillars require reinforcement against side crash but also against front crash and to remove vibration and hardness during driving. The rear of the vehicle and the C pillars require reinforcement against rear crash and also against vibration and hardness during driving. The A, B and C pillars all require strengthening against roll over crash particularly at the top of the pillars. Reinforcement has been provided in a variety of ways; traditionally reinforcement was provided by increasing the gauge of the steel from which the vehicle structures were made or by the provision of double walled steel structures. Both these techniques resulted in an undesirable increase in the weight of the vehicle adversely affecting fuel consumption. Ways have therefore been developed to provide reinforcement without an undesirable increase in the weight of the vehicle. One such technique has been the use of rigid foams (such as epoxy foams or rigid polyurethane foams) and in some instances the use of rigid foams supported on a rigid carrier which itself provides reinforcement to the structure.

It is important that the provision of the reinforcement be achieved within the normal vehicle manufacturing operations. One important operation in vehicle manufacture is the provision of an anti corrosion coating on the internal surfaces of the metal structures and this is often accomplished by what is know as the elctrocoat (or e coat) process. In this process the assembled metal frame that forms the basic structure of the vehicle passes through a large bath of anti corrosion fluid which is deposited electrolytically on the metal and the coating formed is then cured by passing the coated metal structure through an oven where it is dried and hardened. Techniques have been developed whereby a reinforcing part comprising a carrier material which provides reinforcement carrying a heat activated adhesive foamable material is placed within the tubular metal structure, the metal structure is subject to the e-coat process. The foamable material is designed so that it will foam and develop adhesive properties under the conditions employed for the drying and/or hardening of the anti corrosion coating. In this way the foamable material can be foamed after deposition of the anticorrosion coating during the drying and curing of the coating. The foamed material therefore serves the dual function of adhering the carrier to the inner surface of the tubular structure so that the carrier can provide a reinforcing effect and also contributing to the reinforcement.

As well as providing reinforcement it is important that the reinforcement can be re- established when repairs and replacement parts are required after a vehicle accident.

Examples of such reinforcing may be found in Japanese patent application 7-117728 which shows reinforcement of a side sill and a door panel, PCT publication 95/32110 which shows reinforcement of a radiator support beam, PCT publication 93/05103 which shows reinforcement of an A pillar, PCT publication 00/37302 which shows reinforcement of the top of the B pillar and PCT publication 99/39882 which shows reinforcement against NVH at the three cornered joint at the top of the C pillar. To date however the reinforcement that has been provided has been the provision of a single type of reinforcement at a particular location in the vehicle.

We have now developed multi-functional reinforcing systems which can be used to provide two or more different forms of reinforcement at a single location in a vehicle and/or which can be integrated to provide various types of reinforcement at different locations within the vehicle.

An object of the present invention is to increase the safety of vehicle occupants by increasing the ability of the vehicle structure to absorb and dissipate undesirable energy, such as that generated by the impact of a crash before the energy can be transferred to the occupied area of the vehicle where it can cause injury.

Accordingly the present invention provides a multi-functional unitary member for the reinforcement of a vehicle comprising at least a section designed primarily to provide one form of reinforcement and a section designed primarily to provide a second form of reinforcement.

The member may provide two or more forms of reinforcement and the forms of reinforcement that may be provided include reinforcement against front crash, reinforcement against side crash, reinforcement against rear crash, reinforcement against roll over and reinforcement during general running against NVH. The invention is particularly concerned with members that provide reinforcement against one or more forms of crash together with reinforcement against NVH.

The reinforcing member of the present invention comprises a core supporting member carrying a foamable material which can be activated to foam after the member is placed within the vehicle structure to bond the core member to the interior surface of the vehicle structure. The different forms of reinforcement that are provided by the member can be provided by the provision of a different structure within the core supporting member and/or by the distribution of the foamable material over the surface of the core supporting member coupled with the location of the member within the vehicle structure and the extent to which its profile matches the profile of the vehicle structure it is required to reinforce. Examples of features that may be employed within a single member to provide various forms of reinforcement are i) Provision of a particular rib structure within the member to resist bending and thus provide reinforcement against NVH. ii) Provision of a particular rib structure within the member to provide impact resistance, iii) Design of the member to provide a space between the metal of the vehicle and the member to allow a controlled degree of collapse of the metal upon impact prior to contact with the member. iv) Provision of foam at only those locations where optimum rigidity is required such as reinforcement against NVH. v) Use of a reinforcing member across and extending into two or more vehicle tubular structures at location(s) where the structures intersect. vi) The joining of two or more remote reinforcing parts to enable energy transfer between the parts.

In order to achieve their function the reinforcing members of the present invention tend to be larger and to have a more complex structure than many previous structural reinforcing members. It has been found that such structures can be conveniently formed by injection moulding of thermoplastics and accordingly it is preferred that the carrier be produced by injection moulding, preferably of nylon and particular nylon that is fibre filled especially glass filled nylon. In these reinforcing parts the carrier or a substrate is usually formed from a rigid polymer such as glass fibre reinforced polyamide or polypropylene. Polyamides, particularly glass filled polyamides are suitable materials due to their high strength to weight ratio. It is preferred that the moulding is provided with means enabling fluid drainage. For example, holes may be provided in the moulding to allow the drainage of water, which may condense in the vehicle structure over time.

We have found that with the larger parts a bigger gap between the foamable material and the metal may be required to allow for variations in the tolerance of the metal and the carrier due to variations in the process. For example whereas a gap of 2 millimetres may have been sufficient for smaller parts a gap of 3 to 9 millimetres, typically 3 to 5 millimeters may be required to ensure that the part can be placed within the metal structure.

In the embodiments of this invention which employ the bigger gap then a thicker layer of foam is required to bridge the gap which may require a faster expanding foam. It is also preferred that the foamable material be overmoulded onto the carrier, alternatively it can be heat bonded to the carrier or can be attached by a fastening system. A preferred process for the production of mouldings is described in our co-filed application reference PALLBA361. Examples of suitable foamable material include foamable epoxy- base resins and examples of such materials are the products L5206, L5207, L5208 and L5209, which are commercially available from L & L Products of Romeo Michigan USA, and the Core Products 5204, 5206, 5205 and 5208 available from Core Products, Strasbourg, France. The product should be chosen so that it can be bonded at temperatures below that at which it will foam, typically 80⁰C to 90⁰C and according to the rate of expansion and foam densities required. It is further preferred that it expand at the temperatures experienced in the oven used to dry and cure the anticorrosion coating deposited in the e-coat process, typically 120°C to 180°C, more typically 130⁰C to 150⁰C. Prior to activation, the expandable adhesive material is preferably dry and not tacky to the touch, since this facilitates shipping and handling and prevents contamination. In a preferred embodiment the foamable material will soften and bond at 80⁰C to 90⁰C and is applied to the moulded carrier when it is at a temperature of 85°C to 11O⁰C.

With the larger mouldings of complex structure and the need to provide foam at only certain locations on the carrier we have found it useful to adopt certain techniques to aid the overmoulding and to guide the foaming. The lattice, honeycomb or ribbed structure that may be required in the carrier to give a certain form of reinforcement can result in the presence of local, relatively small, interconnecting locations in the carrier. If the carrier itself is formed by injection moulding it can be difficult to control the flow of the material used to make the carrier which can result in undesirable thick spots in the carrier at these interconnecting locations. These can be wasteful in material and can also impair the flow of material that is overmoulded on the carrier. For example we have found it convenient to provide channels in the carrier to direct the flow of the foamable material during overmoulding and to prevent it contaminating areas of the carrier designed to serve another function, furthermore it may be desirable to provide holes in the carrier to allow the foamable material to flow to the side of the carrier remote from the point of injection.

Such a feature is described in our co-pending Patent Application Number GB 0413809.5.

We have also found it useful to provide ribs in the carrier which help to direct the direction of expansion of the foamable material as it foams. Such a technique is described in our

United Kingdom Patent Publication GB 2375328A and is useful in that it helps confine the foam to the areas where it is required so economising on the amount of foamable material required. The presence of the ribs also prevents the expanding foam contaminating areas of the carrier designed to serve another function.

The increase in the size and complexity of the reinforcing members brings with it a preferment that the foamable material will foam at a lower temperature. Hitherto foamable materials have been designed to foam at temperatures employed for the drying and baking of the anticorrosion coating in the e-coat process typically between 135°C and 210⁰C. Foaming temperatures of between 115°C and 140⁰C are however preferred in the present invention. It is of course necessary that little if any foaming of the foamable material should occur during the overmoulding process. Accordingly we prefer to use a foamable material that can be overmoulded at temperatures below 120⁰C preferably below 11O⁰C and which can be foamed at temperatures between 115⁰C and 140⁰C preferably between 120⁰C and 135⁰C. Preferred foamable materials comprise an epoxy resin that softens and flows below 120⁰C preferably below 110⁰C and containing a blowing agent and a curing agent that are activated at temperatures in the range 115°C to 140°C, preferably in the range 120⁰C to 135°C.

The reinforcing members of the present invention preferably also satisfy certain other requirements in relation to the construction of the vehicle. For example, they should be provided with means whereby they can be placed and retained in the appropriate location in the vehicle. In many instances the reinforcing members are placed in the vehicle by robots and the members are therefore preferably provided with locator means to enable the robot to locate the member and lift it and place it in the vehicle. The locator means may comprise locations such as holes in the member which can be located by sensors on the robot. In addition the member can be provided with extensions which enable the robot to pick up the member and transfer it to the appropriate location in the vehicle metal structure. The manner by which the member is retained within the metal structure depends upon the position of the part within the structure and whether it is provided to a horizontal or inclined element of the vehicle metal structure. If the member is provided to lie horizontally within the metal structure it may be provided with tabs which enable it to rest on the metal structure. In other environments clips or other forms of attachment may be required.

It is also important that the e-coat fluid can flow through the tubular metal structures when the vehicle metal structure containing one or more reinforcing members passes through the bath of the anti corrosion fluid. Accordingly it may be necessary to provide channels in the reinforcing member to enable flow of the, e-coat fluid. Furthermore it may be necessary to ensure provision of an adequate gap between the foamable material and the metal for flow of the e-coat fluid, and with the larger parts envisaged by the present invention agap of 3 to 9 millimetres typically 5 to 9 millimetres may be required. Such a gap may be provided by an appropriate means of attachment or spacers such as is illustrated in Japanese Patent Application 7-31569. Alternatively or additionally the structural reinforcing member may be provided with small lugs, which enable it to stand away from the interior walls of the hollow structure. In this way fastening devices may not be required and the area of contact between the structural reinforcing member and the interior walls of the frame of the vehicle is minimised. The lugs or spacers should not however be made from the foamable material and when the carrier is produced by injection moulding of thermoplastics it is preferred that the lugs or spacers are integrally moulded with the carrier.

The clearance between the extremity of the reinforcing member and the interior walls of the hollow section is preferably wide enough to enable the liquid used in the electrocoat bath to flow between the reinforcing member and the interior walls of the sections of the vehicle in sufficient quantity to enable an effective anti-corrosion coating to be deposited. On the other hand, the clearance must not be too wide since this can result in a lack of rigidity in the structure when the expandable adhesive is foamed to bond the structural reinforcing member to the walls of the hollow section other than the external panel. It is preferred that the clearance be no more than 1 centimetre and is more preferably 3 to 9 millimetres. The clearance around the whole structure enables a more uniform foam structure to be obtained.

The present invention will now be illustrated by reference to a reinforcing member according to the present invention useful for providing front crash protection, side crash protection and reinforcement against NVH at the bottom of the A pillar of a vehicle and at the joint between the A pillar and the front longitudinal.

Figure 1 is a side view of the reinforcing member showing the side that faces into the vehicle.

Figure 2 is a side view of the reinforcing member showing the side that faces the outside of the vehicle.

Figure 3 is a view of the side of the reinforcing member that faces the front of the vehicle and Figure 4 is a view of the side of the reinforcing member that faces the back of the vehicle.

Figure 1 shows that the member has a curved surface (1) designed to substantially conform to the curvature of the vehicle metal frame at the bottom of the A pillar where it joins the longitudinal. The member has an upper section (2) designed to protrude into the A pillar; the upper section (3) being provided with foamable material (4) which, when foamed, will adhere the member to the lower section of the A pillar thus providing rigidity and NVH reinforcement. The member also has a middle section (5) which is not provided with foam and which is recessed to provide a cavity into which the metal of the vehicle can be deformed on for example a front crash prior to contacting the member, thus enabling energy dissipation through metal collapse. The section of the member adjacent to the curved surface (1) is provided with a first ribbed structure (6) designed to absorb maximum load whereas the lower section (7) is provided with a second different ribbed structure (8) designed to withstand impact and provide protection against front impact. Figure 2 shows how the foamable material (9) is located between pairs of ribs (10,11) to guide the direction of foaming. Also shown are holes (12, 13 and 14) which serve as locators to enable a robot to locate and position the part. Extensions (15 and 16) are provided to allow a robot to pick up and move the part.

The invention is further illustrated by reference to a reinforcing member according to the present invention useful for providing front crash protection, side crash protection, rear crash protection and NVH protection and, optionally, a degree of front crash protection at the position where the B pillar joins the longitudinal.

Figure 5 is a view of the side of the reinforcing member that faces into the vehicle.

Figure 6 is a view of the side of the reinforcing member that faces the outside of the vehicle.

Figure 7 is a view of the side of the reinforcing member that faces the front of the vehicle.

Figure 5 shows that the member has an upper section (17) designed to protrude into the base of the B pillar and two arms (18) and (19) that make up a lower section and which protrude into the longitudinal section of the vehicle frame at either side of the base of the B pillar. Figure 5 shows that the upper section (17) has two areas of curvature (18) and (19) designed to substantially conform to the forward and rearward curvatures of the metal structure at the base of the B pillar. These areas of curvature are provided with foamable material (20) as are the other areas of the upper section shown in Figures 6 and 7 so that when foamed the foam rigidly adheres the member within the bottom of the B pillar providing rigidity and NVH reinforcement. Figure 6 shows that the base of the member is provided with a ribbed structure (2) that will provide reinforcement against side impact. Figure 6 further shows holes (21) and (22) that will act as locators for a robot in locating the part and positioning the part within the vehicle structure. Figure 6 further shows additional holes (23) and (24) in the member which enable the foamable material to flow through the member during overmoulding of the carrier with the foamable material.

Figure 6 also shows an attachment means (25) which is provided to enable the member that reinforces the base of the B pillar to be attached to a member reinforcing the bottom of the A pillar, such as that shown in Figure 1. This enables the B pillar reinforcing member to contribute to front crash reinforcement.

The invention is further illustrated by reference to a reinforcing member according to the present invention useful for providing side crash reinforcement, front crash reinforcement, rollover reinforcement and NVH reinforcement at the top of the B pillar.

Figure 8 is a view of the side of the reinforcing member facing into the vehicle.

Figure 9 is a view of the side of the reinforcing member facing the outside of the vehicle.

Figure 10 is a view of the top of the reinforcing member.

Figure 11 is a view of the underside of the reinforcing member.

Figure 11 shows that the member consists of an upper flat section (26) that extends into the roof section of the vehicle to provide rollover crash protection and also extends either side of the top of the B pillar to provide reinforcement against deformation of the node at the top of the B pillar which can be caused by side crash. The member also consists of a lower section (27) which extends downwardly into the top of the B pillar. Foam (28) is provided on the underside of the member (as shown in Figure 11) and on the lower section (27) so that when foamed the member is rigidly held in position and provides reinforcement against NVH at the join of the B pillar and the roof section. Figure 12 is a cut away view of one side of a vehicle showing all three of the reinforcing members previously illustrated in place and showing the members at the bottom of the A pillar and the bottom of the B pillar connected so that energy can be transferred between the two members. In this way the member at the bottom of the B pillar can help in providing reinforcement against front crash. Accordingly Figure 12 illustrates the overall reinforcement of the vehicle that can be accomplished using the techniques of the present invention. If other components for example bolts are to pass through the reinforcing members during subsequent assembly care must be taken to ensure that holes formed in the reinforcing member for the passage of the bolts are not blocked by the foam as it expands.

Figure 13 is an exploded view of the cross-section of the front longitudinal showing the part of figure 1 (fig 1) joined to the part of figure 5 (fig 5) by a connecting member (29) which allows for the transfer of front crash impact energy from fig 1 to fig 5 so that the embodiment of fig 5 provides reinforcement against front crash.

Whilst the present invention has been illustrated in relation to automotive vehicles it is equally applicable to the reinforcement of other structures based on tubular sections. For example it may be used in the reinforcement of railroad vehicles, aircraft, ships, boats and in building construction.

Claims

1. A multi-functional unitary member for the reinforcement of a vehicle comprising at least a first section designed primarily to provide one form of reinforcement and a section designed primarily to provide a second form of reinforcement.

2. A member according to claim 1 in which the forms of reinforcement are selected from reinforcement against front crash, reinforcement against side crash, reinforcement against rear crash, reinforcement against roll over and reinforcement during general running against NVH.

3. A member according to claim 2 in which the members provide reinforcement against one or more forms of crash together with reinforcement against NVH.

4. A member according to any of the preceding claims comprising a core supporting member carrying a foamable material which can be activated to foam after the member is placed within the vehicle structure to bond the core member to the interior surface of the vehicle structure.

5. A member according to any of the preceding claims in which the different forms of reinforcement that are provided are provided by the provision of a different structure within the member and/or by the distribution of the foamable material over the surface of the core supporting member coupled with the location of the member within the vehicle structure.

6. A member according to any of the preceding claims in which two or more of the following features are employed within a single member to provide various forms of reinforcement i) provision of a particular rib structure within the member to resist bending and thus provide reinforcement against NVH. ii) provision of a particular rib structure within the member to provide impact resistance. iii) design of the member to provide a space between the metal of the vehicle and the member to allow a controlled degree of collapse of the metal upon impact prior to contact with the member. iv) provision of foam at only those locations where optimum rigidity is required such as reinforcement against NVH. v) use of a reinforcing member extending into two or more vehicle tubular structures at location(s) where the structures intersect. vi) the joining of two or more remote parts to enable energy transfer between the parts.

7. A member according to any of claims 4 to 7 in which the carrier is formed by injection moulding of thermoplastics.

8. A member according to claim 7 in which the carrier is produced by injection of nylon that is fibre filled.

9. A member according to any of claims 4 to 8 in which the foamable material is overmoulded onto the carrier.

10. A member according to claim 9 in which the foamable material is a foamable epoxy-base resins.

11. A member according to any of claims 4 to 10 in which the foamable material expands at the temperatures in the oven used to dry and cure the anticorrosion coating deposited in the e-coat process.

12. A member according to any of claims 4 to 11 in which the foamable material foams at a temperature of between 115°C and 140⁰C.

13. A member according to any of the preceding claims provided with means whereby the member can be placed and retained in the appropriate location in the vehicle.

14. A member according to any of the preceding claims provided with locator means to enable a robot to locate the member and lift it and place it in the vehicle.

15. A member according to claim 14 in which the locator means comprises holes in the member which can be located by sensors on the robot.

16. A member according to claim 14 or claim 15 provided with extensions which enable the robot to pick up the member and transfer it to the appropriate location in the vehicle structure.

17. A member according to any of the preceding claims adapted to lie horizontally within the metal structure and provided with tabs which enable it to rest on the metal structure.

18. A member according to any of the preceding claims provided with channels to enable flow of the e-coat fluid.

19. A member according to any of the preceding claims for providing front crash protection, side crash protection and reinforcement against NVH at the bottom of the A pillar of a vehicle and at the joint between the A pillar and the front longitudinal.

20. A member according to any of claims 1 to 18 for providing side crash protection, and NVH protection at the position where the B pillar of the vehicle joins the longitudinal.

21. A member according to claim 20 further providing front crash protection.

22. A member according to any of claims 1 to 18 for providing side crash reinforcement, front crash reinforcement, rollover reinforcement and NVH reinforcement at the top of the B pillar of the vehicle.

23. A vehicle component reinforced by a member according to any of the preceding claims.

24. A vehicle component according to claim 23 in which the member is bonded to the shell of the vehicle component by the foamed material.