GB2326853A

GB2326853A - Reinforcement for a motor vehicle structure

Info

Publication number: GB2326853A
Application number: GB9805553A
Authority: GB
Inventors: Yasukazu Fukuda; Norio Hatamori; Haruo Fujita
Original assignee: Daihatsu Motor Co Ltd
Current assignee: Daihatsu Motor Co Ltd
Priority date: 1997-06-30
Filing date: 1998-03-16
Publication date: 1999-01-06
Anticipated expiration: 2018-03-16
Also published as: GB9805553D0; GB2326853A8; DE19812679A1; GB2326853B; DE19812679B4; MY120726A

Description

SPECIFICATION REINFORCING STRUCTURE FOR SUBSTRUCTURE OF BODY OF AUTOMOBILE BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a reinforcing structure for the substructure of the body of an automobile.

Prior Ar t Conventionally, some automobiles have a car body constructed as follows.

Said car body comprises a car body frame, and a main body supported on the upper surface of said car body frame. Said car body frame comprises a main frame extending longitudinally over a long distance and a subframe supported in the front portion of said main frame. Said subframe has an engine supported thereon and front wheels suspended therefrom, and said main frame has rear wheels suspended in the rear portion thereof, said front and rear wheels cooperating with each other to support said car body on a travel surface.

Said main frame, as seen in a plan view, has a pair of longitudinal frame members, i.e., side frames, of sheet metal.

Each side frame comprises a pair of side plates spaced away from and opposed to each other, and a bottom plate which integrally connects both side plates along their lower end edges, so that the side frame is substantially U-shaped in the cross section of any longitudinal portion thereof. Said side frame comprises an inclined member extending obliquely rearwardly downward, a horizontal member extending from one of the longitudinal ends, or rear end, of said inclined member substantially horizontally in the direction in which it is spaced away from said inclined member, i.e. , extending rearward, and a bend which constitutes the portion extending from said inclined member to the horizontal member.

Further, a support bracket for supporting said subframe which is part of said car body frame is attached to the outer surface of the bottom in the cross section of a longitudinal intermediate portion of said inclined member.

The horizontal members of both side frames have a floor panel mounted thereon which constitutes the substructure of said main body and said floor panel is joined at its sides by spot-welding to the upper surfaces of said horizontal members.

The internal portion of said main body disposed above said floor panel provides the car interior.

The conventional construction described above, however, has the following problems.

During the forward travel of an automobile of said construction, if it collides with some object lying in front of it, such as another car, (hereinafter referred to as forward collision), the shock imparted to the car body flows from the front end of said side frame to the rear end of this side frame while flowing through said subframe and said support bracket to the bottom of said inclined member.

And when the shock is imparted longitudinally of the side frame, as described above, a bending stress is imposed concentrically on said bend, posing the danger of this bend being easily greatly bent as the upper portions of both lateral plates in said bend are deformed in such a manner as to approach each other.

Further, when said shock is imparted to the bottom of said inclined member through said support bracket, a stress is imposed concentrically on the bottom of said inclined member in the vicinity of said support bracket, posing the danger of said bottom also being easily deformed.

Therefore, it may be contemplated providing reinforcing members for respectively reinforcing said bend and the intermediate portion of the bottom of said inclined member ; this, however, increases the number of parts of the car body frame to complicate the arrangement, posing the danger of the weight being increased.

Further, as described above, upon "forward collision", when said horizontal member is subjected to a longitudinal compressive force due to said shock, it tends to bend into an arc of large radius, as seen in a side view. In this case, said horizontal member and said floor panel which is joined to the upper surface of said horizontal member and which tends to bend together with said horizontal member differ from each other in the amount of change in the longitudinal dimension, resulting in a large shearing force produced in the weld joint between the horizontal member and the floor panel, said joint being easily broken, causing the floor panel to peel from the horizontal member with ease, decreasing the strength of the horizontal member by an amount corresponding thereto; thus, there is a danger of the horizontal member being further bent easily to a large degree after undergoing said arcuate bending.

And when said bend and horizontal member are bent with ease by the shock, as described above, the amount of plastic deformation of the side frame is decreased, thereby impairing the absorption of the energy based on said shock. As a result, a heavy shock is imparted to the side associated with the car interior, while the bending of said bend and horizontal member can increase the deformation of the car interior.

SUMMARY OF THE INVENTION The summary of the invention is as follows.

The present invention provides a reinforcing structure for the substructure of the body of an automobile, comprising a car body 2, a car body frame 3 which, as seen in a plan view of said car body 2, has a frame member 13 of sheet metal extending over a long distance in one direction, said frame member 13 having a pair of side plates 20 spaced away from and opposed to each other, and a bottom plate 21 which integrally connects both side plates 20 along their lower end edges, so that said frame member 13 is substantially U-shaped in the cross section of any longitudinal portion thereof, said frame member 13 having an inclined member 30 extending obliquely downward, and a horizontal member 31 extending from one of the longitudinal ends of said inclined member 30 substantially horizontally in the direction in which it is spaced away from said inclined member 30, with a support bracket 35 attached to the outer surface of the bottom in the cross section of a longitudinal intermediate portion of said inclined member 30 for supporting a subframe 6 which is part of said car body frame 3, wherein: said reinforcing structure includes a reinforcing member 38 extending along said frame member 13 and fitted in said frame member 13, one end side 38a of said reinforcing member 38 being joined to vertical intermediate portions of both side plates 20 of said horizontal member 31 in the vicinity of a bend 32 extending from said inclined member 30 to said horizontal member 31, the other end side 38b of said reinforcing member 38 being joined to the bottom plate 21 of said inclined member 30 in the vicinity of said support bracket 35.

Another form of the invention provides a reinforcing structure for the substructure of the body of an automobile, comprising a side frame 13 of sheet metal extending longitudinally of a car body 2 and substantially U-shaped in the cross section of any longitudinal portion thereof, a floor panel 26 joined to the upper surface of said side frame 13, said side frame 13 comprising an inclined member 30 extending rearwardly downward, and a horizontal member 31 extending from the rear end of said inclined member 30 substantially horizontally rearward, wherein: a reinforcing member 44 is directly joined to the upper surface of a bend 32 extending from said inclined member 30 to the horizontal member 31, while another reinforcing member 45 is provided on the upper surface of the portion of said floor panel 26 corresponding to said horizontal member 31, said horizontal member 31, floor panel 26 and said another reinforcing member 45 being integrally joined together.

An object of the present invention is to enable the frame member possessed by the car body frame to effectively resist the shock produced by "forward collision , and more particularly an object is to reinforce the bend of the side frame which is the frame member and the bottom of the inclined member disposed in the vicinity of support bracket in said side frame such that they will not be easily bent or deformed by said shock.

A further object of the invention is to achieve the reinforcement of the frame member by a simple arrangement in such a manner as not to involve increasing the weight.

Another object of the invention is to ensure that upon "forward collision of an automobile, the side frames are sufficiently plastically deformed to sufficiently absorb the energy based on the shock to minimize the shock to be imparted to the side associated with the car interior so as to restrain the deformation of the car interior more effectively.

Other objects, arrangements, functions and effects than those described above will become apparent from the following detailed description of the invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate a preferred embodiment of the invention.

Fig. 1 is a side view of the front portion of a car body; Fig. 2 is a plan view of the front portion of the car body; Fig. 3 is a fragmentary enlarged view of Fig. 1; Fig. 4 is a sectional view taken along the line 4 - 4 in Fig. 3; Fig. 5 is a sectional view taken along the line 5 - 5 in Fig. 3; and Fig. 6 is a sectional view taken along the line 6 - 6 in Fig. 3.

DESCRIPTION OF THE PREFERED EMBODIMENTS In Figs. 1 and 2, the numeral 1 denotes an automobile, and the arrow Fr points ahead. The car body 2 of said automobile 1 comprises a car body frame 3 of sheet metal and a main body 4 of sheet metal supported on the upper surface of the car body frame 3. The car body frame 3 comprises a main frame 5 extending longitudinally over a long-distance, and a subframe 6 which is supported by the front portion of said main frame 5 and which is part of said car body frame 3 but which is separate from said main frame 5. The subframe 6 has an engine supported thereon and a pair of front wheels 7 suspended therefrom, while the main frame 5 has a pair of rear wheels suspended in the rear portion thereof, said front wheels 7 and rear wheels cooperating with each other to support the car body 2 on a travel surface 9.

The car body 2, as seen in a plan view, is substantially symmetrical with respect to the car body centerline 12 extending widthwise of the car. The main frame 5 comprises a pair of longitudinal side frames 13, 13 which are frame members, side sills 14 respectively disposed outside said side frames 13, 13 and disposed, as seen long udinally, between the front wheels 7 and the rear wheels, and a plurality of cross members 15, 16, 17 and 18 extending widthwise of the car to join both side frames 13, 13 to both side sills 14, 14.

In all figures, each side frame 13 is press-formed of a single strip of sheet metal extending longitudinally over a long distance. Each side frame 13 has a pair of side plates 20, 20 somewhat spaced away from and opposed to each other, and a bottom plate 21 for integrally joining said side plates 20, 20 along their lower end edges, and outward flanges 22 integrally outwardly extending from the respective upper end edges of said side plates 20. As a result, each side frame 13 is substantially U-shaped in the cross section of any longitudinal portion thereof. Further, each side sill 14 has an outer panel 24 and an inner panel 25 which are opposed to each other as seen widthwise of the car, said panels 24 and 25 being joined together to form a box-shaped cross section.

A floor panel 26 is mounted in the rear portions of both side frames 13 and joined at its sides by spot-welding to the upper surfaces of the rear portions of both side frames 13.

Further, said floor panel 26 is joined at its opposite end edges by spot-welding S to the vertical intermediate portions of the inner panels 25 of said side sills 14.

A dash panel 27 is provided forwardly of said floor panel 26. The rear portion of this dash panel 27 is mounted on the longitudinal intermediate portions of both side frames 13 and the front portion of said dash panel 27 is joined at its sides by spot welding S, to the upper surfaces of the respective intermediate portions of both side frames 13. Further, the front portion of said dash panel 27 extends upwardly away from both side frames 13.

The floor panel 26 and the rear portion of the dash panel 27 constitute the substructure of said main body 4, and the internal portion of said main body 4 disposed above said floor panel 26 and rearwardly of the front portion of said dash panel 27 provides the car interior 28.

Each side frame 13 comprises an inclined member 30, at a longitudinal portion thereof, extending obliquely rearwardly downward, a horizontal member 31 extending substantially horizontally from one longitudinal end, or rear end, of said inclined member 30 and rearwardly away from said inclined member 30, and a bend 32 disposed in a region extending from said inclined member 30 to the horizontal member 31 and integrally connecting them. Further, each side frame 13 has another horizontal member 33 extending substantially horizontally from the other longitudinal end, or front end, of said inclined member 30 and forwardly away from said inclined member 30, these other horizontal members 33 constituting the front portions of both side frames 13.

The front end edge of said floor panel 26 and the rear end edge of said dash panel 27 are superposed and joined by spot welding to the upper surface of said cross member 16 and to the upper surfaces of both outward flanges 22, 22 in said bend 32.

A support bracket 35 of sheet metal is firmly joined by spot welding S2 to the outer surface of the bottom in the cross section of a longitudinal intermediate portion of each inclined member 30. And said subframe 6 is removably supported on the front end of each of said other horizontal members 33 and each of said support brackets 35 by a fastener 34.

There is provided a first reinforcing member 38 of sheet metal which extends along said side frame 13 and which is completely fitted in the inner space 37 of this side frame 13.

This first reinforcing member 38 is press-formed in the same shape as that of said side frame 13, having a pair of side plates 39, 39, and a bottom plate 40, so that it is substantially U-shaped in the cross section of any longitudinal portion thereof.

One end side 38a which is the rear end side of said first reinforcing member 38 is disposed in an intermediate position vertically of each side plate 20, 20 of said horizontal member 31 in the vicinity of the bend 32 of said side frame 13. Each side plate 39 of said one end side 38a is abutted face-to-face against each side plate 20 of said horizontal member 31 and firmly joined thereto by spot welding S3.

On the other hand, each side plate 39 of the other end side 38b which is the front end side of said first reinforcing member 38 and the bottom plate 40 are abutted face-to-face against each side plate 20 of said inclined member 30 and the bottom plate 21 in the vicinity of said support bracket 35 and firmly joined thereto by spot welding 54.

Further, a second reinforcing member 42 of substantially the same cross sectional shape as that of the first reinforcing member 38 is fitted in said first reinforcing member and entirely abutted face-to-face thereagainst and firmly joined by said spot weldings S3 and S4 to said side frame 13 and said first reinforcing member 38, respectively.

A third reinforcing member 44 in the form of an arcuate plate is directly mounted on the upper surfaces of both outward flanges 22, 22 in each bend 32. Each outward flange 22 of each bend 32, the front end portion of the floor panel 26 and the rear end portion of the third reinforcing member 44 are superposed in three layers and integrally spot-welded as at S,.

Further, each outward flange 22 of each inclined member 30, the rear end portion of the dash panel 27 and the front end portion of the third reinforcing member 44 are superposed in three layers and integrally spot-welded as at S6. Further, each outward flange 22 of said bend 32, the front end portion of the floor panel 26, the rear end portion of the dash panel 27 and the third reinforcing member 44 are superposed in four layers and integrally spot-welded as at S,. That is, said members are firmly joined together by said spot weldings S5, S6, S7.

A fourth reinforcing member 45 extending longitudinally over a long distance is provided on the upper surface of the portion of said floor panel 26 corresponding to each horizontal member 31, and the horizontal member 31, floor panel 26 and fourth reinforcing member 45 are superposed in three layers and integrally spot welded as at Ss. That is, these members are firmly joined together by said spot welding Ss.

According to the above arrangement, as seen longitudinally of the side frame 13, the cross section in said bend 32 is substantially in the shape of a double box with the bend 32, floor panel 26, dash panel 27, first reinforcing member 38, second reinforcing member 42, and third reinforcing member 44 superposed one upon another; thus, said bend 32 is fully reinforced, having improved strength and rigidity.

Further, in that said first reinforcing member 38 is joined to each side plate 20 and bottom plate 21 of said inclined member 30 in the vicinity of said support bracket 35, the bottom of the inclined member 30 in the vicinity of said support bracket 35 has been fully reinforced, having improved strength and rigidity.

Consequently, the bend 32 of said side frame 13 and the inclined member 30 in the vicinity of the support bracket 35 are protected from being easily bent or deformed at their bottoms upon "forward collision" by the shock, which means that the aforesaid reinforcements are effectively achieved. As a result, even if the car body 2 is fully subjected to said shock, the car body 2 and car interior 28 are more reliably maintained in their respective predetermined shapes, and the production of vibrations and attendant noises in the car body frame 3 during travel is more reliably prevented.

And in the above case, one end side 38a of the first reinforcing member 38 reinforces said bend 32, while the other end side 38b of said first reinforcing member 38 reinforces the bottom of the inclined member 30 in the vicinity of said support bracket 35. In other words, aplurality of places where a stress concentration tends to occur are reinforced by the first single reinforcing member 38, which means that this reinforcement is achieved by a simple arrangement designed to avoid the increase of weight.

Furthermore, said first and second reinforcing members 38 and 42 are entirely fitted in the inner space 37 of said side frame 13; therefore, the provision of said first and second reinforcing members 38 and 42 does not cause any change in the external appearance or shape of said side frame 13 and hence there is no change in the arrangement related to other members, such as the side frame 13 and cross members 16 and 17.

Thus, whereas said reinforcement has been provided by said first and second reinforcing members 38 and 42, the possibility that the arrangement and operation for assembling them with other members such as said side frame 13 and cross members 16 and 17 become complicated is prevented.

Further, as described above, upon "forward collision", if a shock directed rearward is imparted to the front end of said side frame 13, a stress based on this shock concentrates on said bend 32, posing the danger of this bend 32 being bent easily to a large degree as shown in dash dot line in Fig. 1. And if said bend 32 is bent, this means that the U-shaped cross section in this bend 32 is caused to undergo a change in shape to a large degree.

Therefore, with attention paid to this point, as described above, the third reinforcing member 44, in addition to the first and second reinforcing members 38 and 42, is joined to the upper surface of said bend 32. Furthermore, said third reinforcing member 44 is directly joined to said bend 32, with the result that said bend 32 is effectively reinforced and the change in cross section due to the shock is prevented. In other words, the fact that the change in the shape of the cross section in the bend is prevented results in prevention of the bending of said bend 32.

On the other hand, since the horizontal member 31 extends substantially horizontally as described above, if it is subjected to said rearwardly directed shock and longitudinally compressed, for example, as shown in dash dot line in Fig. 1, said horizontal member 31, as seen in a side view of the car body 2, tends to bend into an arc of large radius. In this case, the horizontal member 31 and the floor panel 26 joined to the upper surface of the horizontal member 31 both tend to arcuately bend as described above, and since they differ in the amount of change in their longitudinal dimension, a shearing stress is produced in the region where they are joined together by spot welding and this region can be easily broken. If this break occurs, the floor panel 26 easily peels from the horizontal member 31, whereupon the strength of said horizontal member 31 decreases by an amount corresponding thereto; thus, after the horizontal member 31 has been bent into said arc, it is further bent easily to a large degree.

However, as described above, in addition to the first and second reinforcing members 38 and 42, the horizontal member 31 and the fourth reinforcing member 45 have said floor panel 26 sandwiched therebetween and these members are integrally joined by spot welding S; therefore, the floor panel 26 is protected from peeling easily from the horizontal member 31. In other words, the state of joining between the horizontal member 31 and the floor panel 26 is reliably maintained by said fourth reinforcingmember 45, thereby protecting the horizontal member 31 from being easily bent to a large degree.

Therefore, when said side frame 13 is subjected to said shock, it is sufficiently longitudinally compressed to be sufficiently plastically deformed, so that the energy based on said shock is correspondingly sufficiently absorbed. And this energy absorption eliminates the danger of a heavy shock being imparted to the side associated with the car interior 28, and effectively restrains the deformation of the car interior 28 as compared with the case where the bend 32 and the horizontal member 31 are bent to a large degree.

Furthermore, since the bend 32 and horizontal member 31, which are likely to have insufficient strength, are reinforced by the first through fourth reinforcing members 38, 42, 44 and 45, the durability of the side frame 13 to withstand bending, twisting, etc., is improved, this arrangement being useful for the strength of the car body 2.

In Figs. 3 and 6, the fourth reinforcing member 45 has its intermediate portion as seen in the direction of the car width upwardly bulged to form a bulged portion 46. This bulged portion 46 increases the combined vertical dimension of said horizontal member 31 and fourth reinforcing member 45, whereby the bending of the horizontal member 31 when subjected to said shock is prevented more reliably. Thus, the amount of plastic deformation of this horizontal member 31 is increased so that the energy based on the shock is absorbed more reliably.

Further, the end of the cross member 18 is supported on the upper surface of the rear end of said fourth reinforcing member 45, and these members 18 and 45 and the horizontal member 31 and floor panel 26 are superposed in four layers and integrally spot-welded as at Sg. This arrangement also protects the floor panel 26 from peeling from the horizontal member 31 and hence said horizontal member 31 is prevented more reliably from being easily bent to a large degree.

In Figs. 2 and 6, the region of joining between said side sill 14 and the end edge of said floor panel 26 is reinforced by spot welding S1o on a fifth reinforcing member 48 installed across them. when said automobile 1 is subjected to a shock resulting from collision or the like from its outer side, this shock is supported by said side sills 14 and cross members 17, 18 and also strongly by said fifth reinforcing member 48, so that the deformation of the car body 4 is prevented; in other words, deformation of the car interior 28 is prevented.

While the above description refers to the illustrated example, said frame member may be part of said side sill 14 or may be part of the cross members 15, 16, 17, 18 extending over a long distance widthwise of the car. Further, the reinforcement provided by said first and second reinforcing members 38 and 42 may also be applied between the inclined member 30 and the other horizontal member 33.

Further, the present invention may be achieved by suitably combining said individual components.

Claims

WHAT IS CLAIMED IS:

1. A reinforcing structure for the substructure of the body of an automobile, comprising a car body (2), a car body frame (3) which, as seen in a plan view of said car body (2), has a frame member (13) of sheet metal extending over a long distance in one direction, said frame member (13) having a pair of side plates (20) spaced away from and opposed to each other, and a bottom plate (21) which integrally connects both side plates (20) along their lower end edges, so that said frame member (13) is substantially U-shaped in the cross section of any longitudinal portion thereof, said frame member (13) having an inclined member (30) extending obliquely downward, and a horizontal member (31) extending from one of the longitudinal ends of said inclined member (30) substantially horizontally in the direction in which it is spaced away from said inclined member (30) , with a support bracket (35) attached to the outer surface of the bottom in the cross section of a longitudinal intermediate portion of said inclined member (30) for supporting a subframe (6) which is part of said car body frame (3) , wherein: said reinforcing structure includes a reinforcing member (38) extending along said frame member (13) and fitted in said frame member (13), one end side (38a) of said reinforcing member (38) being joined to vertical intermediate portions of both side plates (20) of said horizontal member (31) in the vicinity of a bend (32) extending from said inclined member (30) to said horizontal member (31), the other end side (38b) of said reinforcing member (38) being joined to the bottom plate (21) of said inclined member (30) in the vicinity of said support bracket (35).

2. A reinforcing structure for the substructure of the body of an automobile, comprising a side frame (13) of sheet metal extending longitudinally of a car body (2) and substantially U-shaped in the cross section of any longitudinal portion thereof, a floor panel (26) joined to the upper surface of said side frame (13), said side frame (13) comprising an inclined member (30) extending rearwardly downward, and a horizontal member (31) extending from the rear end of said inclined member (30) substantially horizontally rearward, wherein: a reinforcing member (44) is directly joined to the upper surface of a bend (32) extending from said inclined member (30) to the horizontal member (31), while another reinforcing member (45) is provided on the upper surface of the portion of said floor panel (26) corresponding to said horizontal member (31) said horizontal member (31) , floor panel (26) and said another reinforcing member (45) being integrally joined together.

3. A reinforcing structure substantially as hereinbefore described with reference to and as shown in the accompanying drawings.