SUB-FRAME METHOD AND ARRANGEMENT FOR RETAINING A REAR SECTION OF A SUB-FRAME

Abstract

A sub-frame arrangement (1) in a vehicle and method thereof wherein the sub-frame arrangement comprises a sub-frame (2), a first body member, and rear attachment means for attaching said sub-frame to the first body member. The sub-frame is a dual part sub-frame comprising a lower sheet section (2b) formed in a single piece wherein said lower sheet section extends the entire length of said sub-frame. The lower sheet section is further formed with two rear portions (21) each extending backwards in the travel direction of said vehicle and the rear portions are adapted to host the rear attachment means.

Claims

1. A sub-frame arrangement in a vehicle, said sub-frame arrangement comprising: a sub-frame; a first body member; and rear fastening means for attaching said sub-frame to the first body member, wherein said sub-frame is a dual part sub-frame comprising a top section and a lower sheet section, wherein said lower sheet section is formed in a single piece and extends the entire length of said sub-frame, wherein said lower sheet section further is formed with two rear portions each extending backwards in the travel direction of said vehicle and adapted to deform during a collision, wherein said rear portions are adapted to host the rear fastening means, wherein the rear portions are adapted to deform in a direction downwards and backwards in relation to the travel direction of the vehicle during a collision, allowing the sub-frame to be directed under a passenger cell of the vehicle, characterized in that said sub-frame arrangement further comprises a release attachment means adapted to release the sub-frame during said deformation, and wherein the rear fastening means are adapted to retain the sub-frame during said deformation.

2. The sub-frame arrangement according to claim 1, wherein said top section comprises two towers.

3. The sub-frame arrangement according to claim 1, wherein the rear portions are adapted to deform and the rear fastening means are adapted to retain an engagement between the rear portion of the sub-frame and the first body member during the entire deformation caused by a collision.

4. The sub-frame arrangement according to claim 1, wherein a first rear portion is adapted to deform differently from a second rear portion in order to allow a shorter deformation distance during a moderate overlap collision than during a full front collision.

5. The sub-frame arrangement according to claim 1, wherein at least one of said rear portions is adapted to deform over a second length longer than a first length corresponding to the distance between the release attachment means and the rear fastening means, allowing the rear portion to absorb additional force through limiting the sub-frame movement in the deformation direction.

6. The sub-frame arrangement according to claim 1, wherein said sub-frame arrangement further comprises a second body member and front fastening means adapted to fasten a front section of said sub-frame to the second body member.

7. The sub-frame arrangement according to claim 6, wherein said front fastening means are adapted to release the sub-frame from engagement with the second body member during deformation caused by a collision.

8. The sub-frame arrangement according to claim 1, wherein said lower sheet section has a substantially flat shape formed from a single piece of any one of sheet metal and aluminum.

9. The sub-frame arrangement according to claim 2, wherein the rear portions are adapted to deform and the rear fastening means are adapted to retain an engagement between the rear portion of the sub-frame and the first body member during the entire deformation caused by a collision.

10. The sub-frame arrangement according to claim 9, wherein a first rear portion is adapted to deform differently from a second rear portion in order to allow a shorter deformation distance during a moderate overlap collision than during a full front collision.

11. The sub-frame arrangement according to claim 10, wherein said sub-frame arrangement further comprises a second body member and front fastening means adapted to fasten a front section of said sub-frame to the second body member.

12. The sub-frame arrangement according to claim 11, wherein said lower sheet section has a substantially flat shape formed from a single piece of any one of sheet metal and aluminum.

13. A method for partly releasing a sub-frame of a vehicle during a collision, sub-frame comprising a first body member and rear fastening means for attaching said sub-frame to the first body member, wherein said sub-frame is a dual part sub-frame comprising a top section and a lower sheet section, wherein said lower sheet section is formed in a single piece and extends the entire length of said sub-frame, wherein said lower sheet section further is formed with two rear portions each extending backwards in the travel direction of said vehicle and adapted to deform during a collision, wherein said rear portions are adapted to host the rear fastening means, wherein the rear portions are adapted to deform in a direction downwards and backwards in relation to the travel direction of the vehicle during a collision, allowing the sub-frame to be directed under a passenger cell of the vehicle, characterized in that said sub-frame arrangement further comprises a release attachment means adapted to release the sub-frame during said deformation, and wherein the rear fastening means are adapted to retain the sub-frame during said deformation, the method comprising: deforming the two rear portions backwards relative a travel direction of said vehicle, retaining engagement between said sub-frame and said first body member, releasing the sub-frame from fastening means other than the rear fastening means, deforming the rear portions over a first length corresponding to the distance between said fastening means and the rear fastening means, and directing the sub-frame under a passenger cell of the vehicle when the rear portions deform during a collision.

14. The method according to claim 13, wherein the method further comprises: deforming at least one of said rear portions over a second length longer than the first length allowing the rear portion to absorb additional force through limiting the sub-frame movement in the deformation direction.

15. A vehicle comprising a sub-frame arrangement, said sub-frame arrangement comprising: a sub-frame; a first body member; and rear fastening means for attaching said sub-frame to the first body member, wherein said sub-frame is a dual part sub-frame comprising a top section and a lower sheet section, wherein said lower sheet section is formed in a single piece and extends the entire length of said sub-frame, wherein said lower sheet section further is formed with two rear portions each extending backwards in the travel direction of said vehicle and adapted to deform during a collision, wherein said rear portions are adapted to host the rear fastening means, wherein the rear portions are adapted to deform in a direction downwards and backwards in relation to the travel direction of the vehicle during a collision, allowing the sub-frame to be directed under a passenger cell of the vehicle, characterized in that said sub-frame arrangement further comprises a release attachment means adapted to release the sub-frame during said deformation, and wherein the rear fastening means are adapted to retain the sub-frame during said deformation.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0052] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0053] FIG. 1 illustrates one embodiment of a sub-frame arrangement seen from below.

[0054] FIG. 2 illustrates one embodiment of lower sheet section adapted to be arranged in a sub-frame arrangement, wherein the lower sheet section is illustrated in an isometric view.

[0055] FIG. 3 illustrates one embodiment of the lower sheet section and the top section of the sub-frame arrangement together constituting one embodiment of the sub-frame illustrated in an isomeric view.

[0056] FIG. 4 illustrates one embodiment of sub-frame of the sub-frame arrangement indicating the front section of the sub-frame.

[0057] FIG. 5 illustrates one embodiment of the sub-frame arrangement comprising the sub-frame, fastening means, and body members, wherein the arrangement is arranged in a vehicle.

[0058] FIG. 6 illustrates one embodiment of the sub-frame arrangement after deformation caused by a collision.

[0059] FIG. 7 illustrates one embodiment of the sub-frame arrangement comprising the sub-frame, fastening means, and body members, wherein the arrangement is arranged in a vehicle.

[0060] FIG. 8 illustrates one embodiment of the sub-frame arrangement after deformation caused by a collision.

[0061] FIG. 9 illustrate one embodiment of the sub-frame arrangement during a moderate overlap collision.

DESCRIPTION OF EMBODIMENTS

[0062] In the following, a detailed description of different embodiments of the sub-frame arrangement is disclosed under reference to the accompanying drawings. All examples herein should be seen as part of the general description and are therefore possible to combine in any way of general terms. Individual features of the various embodiments and aspects may be combined or exchanged unless such combination or exchange is clearly contradictory to the overall function of the disclosed arrangement.

[0063] Briefly described the invention relates to a sub-frame arrangement comprising a dual part sub-frame with a lower sheet section that is produced in a single section. The lower sheet section further comprises two rear portions arranged to attach the rear section of the sub-frame to the body of a vehicle. The rear portions are adapted to deform while retaining an engagement with the body members of the vehicle and through all stages of a crash maintain said engagement.

[0064] FIG. 1 illustrates one embodiment of the sub-frame arrangement 1 in a vehicle wherein the sub-frame 2 is attached to body members 3a, 3b. The embodiment as shown in FIG. 1 illustrates the sub-frame arrangement 1 during normal conditions where no crash has occurred. The person skilled in the art understands that FIG. 1 only illustrates parts of the components that would be arranged in a vehicle and that the illustration only is one example adapted to illustrate the characteristics of the sub-frame arrangement 1. FIG. 1 further illustrates that the sub-frame 2 is attached with front fastening means 4b and rear fastening means 4a adapted to secure the sub-frame 2 within the sub-frame arrangement 1. The sub-frame 2 is thereby fastened to the body members 3a, 3b of the vehicle body.

[0065] The illustration of FIG. 1 shows the sub-frame arrangement 1 from below and thereby also the sub-frame 2 from below. The sub-frame 2 is a dual part sub-frame constituted of two main sections, a top section 2a and a lower sheet section 2b. In FIG. 1 is the lower sheet section 2b clearly visible while only parts of the top section 2a are in view. The remaining parts of the top section 2a are blocked from view by the lower sheet section 2b. However, it should be noted that in one embodiment as illustrated in FIG. 1 are the front fastening means 4b arranged to fasten a front section of the sub-frame 2 through fastening the top section 2a.

[0066] FIG. 1 further illustrates the two rear portions 21 that extends backwards from a main body of the lower sheet section 2b of the sub-frame 2. The rear portions 21 hosts the rear fastening means 4a, preferably two on each side of the sub-frame as illustrated in the embodiment of FIG. 1.

[0067] In one embodiment as illustrated in FIG. 1 are the front body members 3b extending forward and together constituting part of the engine compartment. However, the person skilled in the art understands that the design and embodiments of the body members may be altered to any form of suitable design within the scope of the solution.

[0068] FIG. 1 further illustrates one embodiment wherein a release attachment means 4d adapted to fasten the sub-frame 2 in the sub-frame arrangement 1 and thereby during normal driving conditions keep the sub-frame in fixed engagement within the vehicle. The distance between the release attachment means 4d and the rear fastening means 4a is in one embodiment selected to determine the deformation direction of the sub-frame 2. I.e. in order to direct the sub-frame 2 under a passenger cell of the vehicle.

[0069] FIG. 2 illustrates one embodiment of the lower sheet section 3b of the sub-frame 2 in detail. The lower sheet section 2b is formed from a single piece and comprises two rear portions that extends backwards in order to create deformation distance for the sub-frame 2 while enabling that the sub-frame 2 is directed underneath a passenger cell in the event of a front collision. The term collision as used herein might refer to any form of crash and it should be noted that similar deformation might occur from other events than a front collision. However, the main scope of the invention is to resolve issues relating to the differences in characteristics between front collisions wherein a large collision area is affected and small offset collisions wherein only a fraction of the front area absorbs the collision force.

[0070] FIG. 2 further illustrates that the lower sheet section 2b of the sub-frame 2 might comprise any number of apertures, metal stampings, pressings, or other alterations to the form of the lower sheet section 2b. In one embodiment are at least some of the mentioned machining's to the lower section 2b adapted to enable engagement with the top section 2a.

[0071] FIG. 2 further illustrates that the rear portions 21 of the lower sheet section 2b in one embodiment comprises apertures 25 adapted to host the rear fastening means 4b. In a preferred embodiment each rear portion 21 comprises two apertures 25.

[0072] FIG. 3 illustrates one embodiment of the assembled sub-frame 2 comprising both the lower sheet section 2b and the top section 2a. FIG. 3 further illustrates one embodiment of the top section 2a comprising two towers 22 extending upwards from the main body of the sub-frame 2. In one embodiment are front attachment sockets 33 arranged at the top of each tower 22 which are adapted to host fastening means 4b.

[0073] FIG. 3 further illustrates the two towers 22 which hosts the attachment sockets 33. The attachment socket comprises a weakened portion 42. The attachment socket 33 comprising a weakened portion 42 is in one embodiment adapted to deform in a way that the weakened portion 42 gives way opening up the attachment socket 33 allowing for the fastening means 4b to be released from the attachment socket 33 and thereby releasing the front section 31 of the sub-frame 2.

[0074] FIG. 4 illustrates one embodiment of the sub-frame 2 wherein the front section 31 and the rear section 32 are illustrated.

[0075] FIG. 5 illustrates one embodiment of the sub-frame arrangement 1 wherein the sub-frame 2 is arranged within a vehicle and additional components of the vehicle are comprised in the illustration. The sub-frame 2 is attached to body members of the vehicle through front fastening means 4b and rear fastening means 4a. In one embodiment are the fastening means 4a, 4b bolts arranged through going through apertures in the sub-frame 2. FIG. 5 further illustrates the sub-frame arrangement 1 in a state wherein no collision or crash has occurred, i.e. during normal driving conditions.

[0076] FIG. 6 illustrates one embodiment of the sub-frame arrangement 1 wherein a collision has occurred, or a collision is in progress, wherein the sub-frame 2 thereby has deformed backwards and the rear portions 21 have deformed allowing the sub-frame 2 to be directed in a direction towards the space underneath the passenger cell 50.

[0077] In one embodiment is the sub-frame 2 released from the front fastening means 4b during deformation caused by a collision while the rear portions 21 deforms in a direction downwards and backwards in relation to the travel direction of the vehicle. Through the deformation of the rear portions 21 are force absorbed while the sub-frame 2 is directed towards the space underneath the passenger cell 50.

[0078] FIG. 7 illustrates one embodiment wherein the sub-frame arrangement 1 is shown from a side view wherein the details of the sub-frame 2 is further illustrated. The sub-frame 2 is retained in the front section 31 by front fastening means 4a that are passing through a fastening socket 33 creating an engagement between the sub-frame 2 and the body members 3. The sub-frame 2 is further attached to the vehicle in its rear section 32 by the fastening means 4a passing through the sub-frame 2, in more detail passing through the rear portions 21, and engaging with the body of the vehicle.

[0079] FIG. 8 illustrates one embodiment of the sub-frame arrangement wherein the the rear portions 21 have deformed directing the sub-frame under the passenger cell 50. In one embodiment the front fastening means 4b are left in the body member 3 of the vehicle while the attachment socket 33 opens up and releases the front section 31 of the sub-frame.

[0080] FIG. 9 illustrates one embodiment of the sub-frame arrangement 1 wherein a moderate overlap collision has occurred deforming the sub-frame 2 more on the left side than on the right side of the vehicle. The rear portions 21 has deformed differently wherein the first rear portion 21 a has deformed in a way restraining the rotation force of the deformation while the second rear portion 21 b has deformed absorbing a large amount of longitudinal force from the collision.

[0081] Depending of the collision direction, force, and collision area of the vehicle the force that shall be absorbed and the deformation distance that shall not be exceeded differs. For example, during absorption of collision force from a full front collisions it is beneficial to maximize the deformation distance. This is in one embodiment of the sub-frame arrangement 1 conducted through slightly decreasing the energy absorption capacity per length unit for full front collisions. The lost energy absorption per length unit is compensated for by a longer deformation distance. This has a beneficial impact on the safety performance of the vehicle.

[0082] According to one embodiment the rear portions 21 are deformed to the point where the rear portions 21 retains the sub-frame 2 from moving further backwards, this occurs when the rear portions 21 reaches their deformation end point.