WO2009113096A2

WO2009113096A2 - Impact absorbing structure for vehicles

Info

Publication number: WO2009113096A2
Application number: PCT/IN2009/000064
Authority: WO
Inventors: Prashant Vinod Navsariwala; Pramod Pannalal Bharadwaj; Dinesh Dilip Nikhumbh
Original assignee: Mahindra & Mahindra Ltd.
Priority date: 2008-01-29
Filing date: 2009-01-27
Publication date: 2009-09-17
Also published as: WO2009113096A3

Abstract

The present invention relates to impact energy absorbing structure for vehicles, which comprising a pair of side crash members (2), upper crash member or cross member (1), a pair of inner reinforcement members (3) forming crash assembly, torsion bar (4) and baffl plates (5) forming an integrated structure This is a complete modular structure which gets bolted to the longitudinal members of the chassis Both the upper crash member and side crash assemblies absorb the additional energy thereby increasing the overall energy absorption

Description

Impact Absorbing Structure for Vehicles

Technical Field:

The present invention relates generally to impact absorbing structure and to automotive front end structure adapted to be mounted on the chassis of an automotive vehicle to absorb impact energy. More specifically, the present invention relates to the impact energy absorbing structure with torsion bar attachable to the motor vehicle as an add-on module to chassis, to absorb kinetic impact energy and convert it into torsion by undergoing deformation.

Background and Prior Art:

Motor vehicles are a part of everyday life for most individuals around the world. Hence human safety has become an important issue while driving the vehicles. Unfortunately, motor vehicle collisions cause a large number of injuries and deaths in countries like India. Consequently, efforts are constantly being made to increase the safety of motor vehicles, particularly in a collision situation. Numerous proposals already have been made to improve safety in the event of impacts between a vehicle and a fixed or movable obstacle, especially in the event of impacts between two vehicles. AU proposals are aimed at absorbing the kinetic energy of the impact in more or less controlled and localized manner, in order to prevent irreparable harm to the passengers.

Automotive manufacturers continuously develop devices intended to improve vehicle safety in front end crashes. Moreover, automotive manufacturers are particularly concerned with vehicle safety in front offset crashes on account of the tendency to cause extensive intrusion into the passenger compartment. Intrusion into the passenger compartment increases the risk of serious injury to the occupants of the vehicle. Such a result is clearly undesirable. In order to ensure higher levels of passenger protection in the interior of vehicles such as automobiles, the recent trend has been toward the establishment of increasingly stringent standards regarding passenger safety measures and the like.

The traditional approach to deliver vehicles more resistant to frontal impact and crashes is by improving the structural strength of such vehicles which can be achieved by incorporating strengthened frames. However, the study revealed that improving the structural strength alone does not provide optimized solution as kinetic energy in crash or impact condition need to be absorbed somewhere. Many approaches have been made to provide a structure which is able to absorb a significant percentage of the impact energy transferred when an object impacts the structure. It is conventionally followed to include the crash boxes within the vehicle in front region so as to absorb at least some kinetic energy in impact situation. Conventionally, some methods are known to describe vehicle impact energy absorbing structures; for example:

European Patent no. 1787870 Al describes vehicle impact energy absorbing structure in particular for front impacts at variable angle. The structure comprises: a pair of longitudinal side struts, a cross-member for connecting the struts which integrally forms a central section and a pair of side end sections inclined with respect to the central section, and a pair of support members of the crash-box type arranged each between a respective strut and a respective side end section of the cross-member. According to the invention, the cross-member has a box-shaped structure comprising a profiled piece with a cross-section which is open towards the struts and the crash-boxes and with a closing wall connected to the profiled piece so as to close the cross-section thereof. Moreover, in the zone of the side end a section of the cross-member, the closing wall of the cross-member is firmly connected to the crash-boxes while it is releasable connected to the profiled piece.

The German patent no. (DE) 10321573A1 and patent application nos. WO 2004/101348A1 and US 2007/ 0132223 Al discloses crash structure for an automotive shell structure which includes two longitudinal members arranged one on each side of the shell structure and are provided with energy-absorbing elements at their front-facing ends. To increase the protection for vehicle occupants in the event of an impact, it is proposed to provide additional energy absorption to channel impact energy into other regions of the shell structure in a controlled manner. European patent no. (EP) 1679234A1 and patent application nos. JP 2006/168535 and US 2006/ 0131902 Al discloses impact energy absorbing structure for vehicle which is capable of absorbing large energy and arranged in a narrow place. The impact energy absorbing member is fixed to a front face of a bumper beam of a car by a clip. The absorbing member is a cylindrical member with a film-like strip and an aluminum strip overlapping each other and spirally wound. When the absorbing member is subjected to a load, the absorbing member is plastically deformed, and absorbs large impact energy to ensure the safety of a pedestrian.

JP 2006/176093 and WO 2006/068008A1 describes a bumper and an impact absorption structure for a vehicle capable of suppressing increase in a mounting space and efficiently absorbing impact associated with vehicle collision. A bumper frame is provided with a bumper reinforce extending in a width direction of the vehicle; and a pair of crash boxes fixed to both ends, extending in a longitudinal direction of the vehicle and having a hollow structure. The bumper reinforce is formed in a plate-like shape having a wall part vertically erected and a pair of opposed wall parts, continued to an upper end and a lower end and bent to a rear side of the vehicle. The crash box has a distal end covered by the wall part 16a, is clamped/ inserted between the opposed wall parts and is fixed to the bumper reinforce.

The Korean patent application No. (KR)2003/ 0075865 describes a structure for a front end of a vehicle is provided to absorb impact and protect passengers by increasing deformation of a crush zone more than deformation of a bumper beam with integrally extending the bumper beam in the crush zone, and to increase the productivity by reducing parts, expenses and process. A front end of a vehicle is composed of a front side member supporting the lower end of a vehicle body, and a bumper beam combined with the front of the front side member. The bumper beam is extended in the crush zone of the front side member to relieve collision energy. The bumper beam absorbs shock with deforming first, and the crush zone absorbs impact secondly at a collision. The bumper beam is deformed more than the crush zone at the collision. Thus, passengers are protected.

EP 1762439A1 and FR 2890620A1 describes motor vehicle bumper beam. The bumper bar, especially for a vehicle with a frame structure, has at least one transverse impact transfer member and shock absorbers. It differs by having part of each shock absorber located inside the transfer member while another part is located outside and behind it and is capable of lodging inside the transfer member in the event of an impact. The transfer member has one or more vertical surfaces with apertures for the shock absorbers to pass through, the front face of each shock absorber either lying flush with or projecting in front of the transfer member.

The Korean patent No. (KR) 2001/0038846 discloses a roll forming impact beam structure which gradually intercepts impact and absorbs impact more securely. An impact beam structure comprises a front plate and a rear plate. The front plate has a first perpendicular part fixed to one end of an energy absorber and having a flange, a second perpendicular part bended to reversed C-form and extended from the first perpendicular part and a third perpendicular part bended to reversed C-form and extended from the second perpendicular part and having a flange symmetrically to the first perpendicular part. The rear panel has a first perpendicular part fixed to one side of the first perpendicular part of the front plate, a second perpendicular part bended to C-form and extended from the first perpendicular part and fixed to one side of the second perpendicular part of the front plate and a third perpendicular part bended to C-form and extended from the second perpendicular part and fixed to one side of the third perpendicular part of the front plate. When a collision occurs, the second perpendicular part of the rear plate absorbs impact as well as the front plate.

While these methods fulfill their respective particular objectives and requirements the aforementioned patents do not describe torsionally assisted frontal impact energy absorbing structure that converts impact energy into torsion energy, thereby reducing its intensity. In this respect, the present invention substatially departs from the conventional concepts and methods described in the prior art, and in doing so provides a method to absorb kinetic impact energy and convert it into torsion by undergoing deformation.

Drawbacks of the Prior Art:

1. In most of the prior art patents, the impact force is directly taken up by the main longitudinal members. 2. No prior art patents convert impact energy into torsion energy, thereby reducing its intensity, before transferring it to the chassis members.

3. No prior art patents comprise side crash assemblies connected via torsion bar at the bottom making it possible to achieve wide area for impact energy absorption.

4. Most of the prior art patents functions properly for the impact angle of 0° i.e. in longitudinal direction.

5. Most of the prior art patents contains less surface area exposure for impact resistance.

6. Most of the prior art patents requires more space due to longitudinal member assembly.

Object of the Present Invention:

The main object of the present invention is to provide the system for absorption of the energy produced by a front impact of the vehicle basically due to the deformation under torsional bending of the torsion bar and buckling of the side crash members.

Another object of the present invention is to provide an automotive shell structure with torsion bar that improves the safety of vehicle occupants in case of impact.

The further object of the present invention is to provide survival space for protection of the occupant of the vehicle. A still further object of the present invention is to eliminate the risk of injury to the vehicle occupants in case of accident, to the greatest possible extent.

A still further object of the present invention is to provide frontal impact absorbing structure, which can absorb a large amount of impact energy and convert it to torsion energy; and can be fitted effectively in the limited front space of the vehicle.

Description of the Drawings of the Present Invention:

Firgure (1) shows the different individual components of frontal impact absorbing structure.

Figure (2) shows the isometric view of frontal impact absorbing structure.

Figure (3) shows the isometric view of frontal impact absorbing structure in deformed condition.

Description of the Present Invention:

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

This invention is illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures. According to Figure (1), upper crash member (1), side crash member (2) and inner reinforcement side crash member (3) are draw sections made of cold roll steel sheet. The draw sections can be made of any tensile material such as aluminum or any suitable metal or FRP composites or combination of thereof which fulfills the strength requirement as that of cold rolled steel sheet. Torsion bar (4) is a steel tube of 33.7 mm diameter and 1.6 mm wall thickness. The torsion bar can be made of any suitable material such as metal or FRP composites or combination of thereof and accordingly having suitable diameter and wall thickness fulfilling the required strength and failure characteristics. It can be made of solid cross section of any shape. Baffle plate (5) is a simple flat plate of 2 mm thickness made from cold rolled steel sheet. The baffle plate can be made of any suitable material such as metal or FRP composites or combination of thereof and accordingly having suitable thickness fulfilling the required strength and purpose. The side crash member (2) and inner reinforcement member (3) are spot welded together to form a box type section called as side crash assembly. The side crash assembly is on both the ends of the structure. Torsion bar (4) is welded at its either end to the side crash assemblies by CO2 welding throughout the periphery of torsion bar. It can be connected by spot welding or hydroforming technique or by any suitable means. The upper crash member (1) is spot welded at its either edge to the side crash assembly to form impact absorbing structure (6) as shown in Figure 2. The behavior of the structure (6) in the event of the impact will be described in Figure 2 which shows the structure in undeformed condition. Upper crash member (1), also called as cross member, is the member of the impact absorbing structure (6) which is subjected to the impact first in case of collision. The impact energy gets transferred through upper crash member (1) to the side crash members (2) and inner reinforcement crash members (3) of the structure (6). The side crash member (2) and inner reinforcement member (3) form a box type section called as side crash assembly. These box sections are so designed that there is formation of crushing zone which absorbs the kinetic energy of frontal impact and gets crushed transferring the rest of the impact energy to chassis members. Two crash assemblies, with inclined configuration, have a front section for connection to the upper crash member having an area greater than that of the rear section for connection to the baffle plate. Torsion bar (4) is also known as crash support member. Most of the kinetic energy of impact is absorbed by this crash support member by means of torsion and rest of the impact energy is transferred to the chassis member. Baffle plate (5) also form a box section at the open end of side crash members to provide more strength to the structure (6). It does not allow the side ends of the crash members to deform and thus provide a better resting surface between the structure (6) and chassis members. The whole structure is attached to the longitudinal members of the chassis through baffle plates (5). The presence of baffle plate (5) in between side crash member (2) and longitudinal member of chassis makes the structure (6) more strong and resistive during frontal impact.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment.

Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.

The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the following claims.

Advantages of the Present Invention:

1. The structure described in the present invention, is more stronger and resistive structure during frontal impact. 2. The structure described in the present invention, increases the protection for vehicle occupants in case of frontal impact or collision.

3. The structure desribed in the present invention, is of minimum weight and it occupies minimum space, resulted into a very cost effective structure.

4. The structure descried in the present invention prevents intrusion of impact, into vehicle occupant compartment.

5. The occupant safety structure provided in the vehicle would increase the sale of the vehicle.

6. The structure described in the present invention is inside the front bumper and hence it does not hinder the aesthetic looks of the vehicle.

Claims

1. Impact energy absorbing structure for vehicles comprising a pair of side crash members (2), upper crash member or cross member (1), a pair of inner reinforcement members (3) forming crash assembly, torsion bar (4) and baffle plates (5) forming an integrated structure.

2. Impact energy absorbing structure for vehicles as claimed in claim

1, wherein inner reinforcement member (3) side crash member (2) are so designed and connected together by CO2 welding or spot welding or bolting or by any means that it form a box type section called as side crash assembly.

3. Impact energy absorbing structure for vehicles as claimed in claim

2, wherein crash assemblies are connected to each other via upper crash member at the top and via torsion bar at the bottom making it possible to achieve wide area energy absorption which is independent of the orientation of the impact force channeled in due to the impact.

4. Impact energy absorbing structure for vehicles as claimed in claim

3, wherein two side crash assemblies have front cross section interfacing with the upper crash member (1) and rear cross section interfacing with the longitudinal members of the chassis via baffle plates.

5. Impact energy absorbing structure for vehicles as claimed in 4, wherein the individual components can be fabricated from steel, aluminum, reinforced plastic or any suitable material of required strength and or combination of thereof.

6. Impact energy absorbing structure for vehicles as claimed in 5, wherein torsion bar which absorbs the impact energy by converting it into torsion can be connected to lower ends of crash assemblies by CO2 welding or spot welding or hydorforming technique or bolting or by any suitable means.

7. Impact absorbing structure for vehicles as claimed in claims 1 to 6 above wherein it can be made of any suitable material such as metal or FRP composites or combination of thereof fulfilling the required strength, failure characteristics and purpose.

8. Impact absorbing structure with torsion bar as claimed above wherein it can be used for front impact, side impact, rear impact or combination of thereof with required modifications.

9. Impact energy absorbing structure for vehicles, substantially as hereinabove described in the specification with reference to the accompanying drawings.