CN112758183A

CN112758183A - Rear auxiliary frame

Info

Publication number: CN112758183A
Application number: CN202011611151.2A
Authority: CN
Inventors: 王进; 孔德俊; 陈定积; 戴锐
Original assignee: Dongfeng Motor Co Ltd
Current assignee: Dongfeng Motor Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-05-07
Anticipated expiration: 2040-12-30
Also published as: CN112758183B

Abstract

The invention discloses a rear auxiliary frame which comprises a plurality of members, wherein each member adopts a variable thickness structure formed by a rolling process, the rear auxiliary frame comprises a front cross beam, a rear cross beam, a left longitudinal beam and a right longitudinal beam, the thicknesses of the front cross beam and the rear cross beam are reduced from the edge to the middle part, the left longitudinal beam and the right longitudinal beam both comprise a rear auxiliary frame mounting point and a connecting rod mounting point, the rear auxiliary frame mounting point is used for being connected with the outside, the connecting rod mounting point is used for being welded with the front cross beam and the rear cross beam, and the thicknesses of the rear auxiliary frame mounting point and the connecting rod mounting point are thicker than those of other areas of the left longitudinal beam and the right longitudinal beam. The invention designs the variable thickness of a plurality of members of the rear auxiliary frame, so that the rear auxiliary frame can form a variable thickness structure through a rolling process. Finally, the thickness of the part with high stress requirement of the rear auxiliary frame is increased, and the thickness of other parts is thinned, so that the requirement on structural strength is met, materials are saved, and the cost is reduced.

Description

Rear auxiliary frame

Technical Field

The invention relates to the technical field of automobile chassis, in particular to a rear auxiliary frame.

Background

When the traditional rear auxiliary frame needs to improve the strength of a local structure, the whole plate thickness needs to be lifted together, and a die is reopened. However, some parts of the rear subframe are not required to have high structural strength, and the overall sheet thickness is increased, which results in material waste and increased cost.

Therefore, there is a need for a rear subframe that can improve the local structural strength, save materials, and reduce costs.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a rear auxiliary frame which can improve the local structural strength, save materials and reduce the cost.

The technical scheme provided by the invention provides a rear auxiliary frame which comprises a plurality of members, wherein each member adopts a variable-thickness structure formed by a rolling process, the rear auxiliary frame comprises a front cross beam, a rear cross beam, a left longitudinal beam and a right longitudinal beam, the thicknesses of the front cross beam and the rear cross beam are reduced from the edge to the middle part, the left longitudinal beam and the right longitudinal beam respectively comprise a rear auxiliary frame mounting point and a connecting rod mounting point, the rear auxiliary frame mounting point is used for being connected with the outside, the connecting rod mounting point is used for being welded with the front cross beam and the rear cross beam, and the thicknesses of the rear auxiliary frame mounting point and the connecting rod mounting point are thicker than those of other areas of the left longitudinal beam and the right longitudinal beam.

Further, the variable thickness structure adopts a size optimization algorithm based on sensitivity, and the thickness of each grid unit in the finite element model is preliminarily set according to a mechanical target to be borne by a corresponding position during design to obtain the preliminary thickness; and then, based on the filter radius constraint, the thickness of one grid unit is related to the thickness of the adjacent grid unit to obtain a regionalized same-thickness design, so that the optimal thickness meeting the performance and the process at the same time is obtained.

Further, the optimal thickness t of the grid cell is calculated according to the following formula:

λ_i＝Max(O，r-dis(i，j))

wherein r is a preset filtering radius, n is the number of grid cells, the distance coefficient lambda, i represents an adjacent grid cell, and j represents a target grid cell.

Further, the rear auxiliary frame comprises eight members which are respectively a front upper cross beam, a front lower cross beam, a rear upper cross beam, a rear lower cross beam, a left upper longitudinal beam, a left lower longitudinal beam, a right upper longitudinal beam and a right lower longitudinal beam, wherein the front upper cross beam and the front lower cross beam are spliced into a front cross beam, the rear upper cross beam and the rear lower cross beam are spliced into a rear cross beam, the left upper longitudinal beam and the left lower longitudinal beam are spliced into a left longitudinal beam, and the right upper longitudinal beam and the right lower longitudinal beam are spliced into a right longitudinal beam.

Furthermore, the rear cross beam comprises a two-wheel-drive rear cross beam and a four-wheel-drive rear cross beam, and the corresponding rear cross beam is replaced according to the application of the rear auxiliary frame.

Furthermore, the front cross beam, the rear cross beam, the left longitudinal beam and the right longitudinal beam respectively comprise two welding seams, and the lengths of the two welding seams are equal.

Furthermore, the front side of the rear auxiliary frame is provided with a flanging bracket, and the flanging bracket is used for contacting with an oil tank.

Furthermore, the flanging support comprises a support body, a first flanging and a second flanging, the first flanging and the second flanging are respectively located on the left side and the right side of the support body, the first flanging and the second flanging are used for contacting with the oil tank, and the support body is installed on the front side of the rear auxiliary frame.

Further, first turn-ups with the second turn-ups includes that oil tank contact site and back sub vehicle frame support to lean on the portion, oil tank contact site extends along vertical direction, back sub vehicle frame support to lean on the portion also extend along vertical direction and with the preceding terminal surface of the front beam of back sub vehicle frame supports and leans on.

Further, each piece of the component is formed through blanking, and at least one pair of opposite side lines on each piece of the component are parallel to each other.

After adopting above-mentioned technical scheme, have following beneficial effect:

the invention designs the variable thickness of a plurality of members of the rear auxiliary frame, so that the rear auxiliary frame can form a variable thickness structure through a rolling process. Finally, the thickness of the part with high stress requirement of the rear auxiliary frame is increased, and the thickness of other parts is thinned, so that the requirement on structural strength is met, materials are saved, and the cost is reduced.

Drawings

The disclosure of the present invention will become more readily understood by reference to the drawings. It should be understood that: these drawings are for illustrative purposes only and are not intended to limit the scope of the present disclosure. In the figure:

FIG. 1 is a schematic view of a rear subframe in accordance with an embodiment of the present invention;

FIG. 2 is an exploded view of the rear subframe in accordance with one embodiment of the present invention;

FIG. 3 is a schematic diagram of a grid cell in an embodiment of the invention;

FIG. 4 is a schematic view of a rear subframe of another embodiment of the present invention;

FIG. 5 is an exploded view of a rear cross member in another embodiment of the present invention;

FIG. 6 is a schematic view of a flange bracket and fuel tank according to an embodiment of the present invention;

FIG. 7 is a schematic view of a turn-up bracket according to an embodiment of the present invention;

FIG. 8 is a schematic view of the projected area of the flange bracket on the fuel tank in one embodiment of the invention;

FIG. 9 is a schematic view of a left stringer in one embodiment of the present invention;

FIG. 10 is a stamped layout view of a left stringer in accordance with an embodiment of the present invention;

FIG. 11 is a thickness profile of the rear subframe according to one embodiment of the present invention.

Reference symbol comparison table:

front beam 1: a front upper beam 11 and a front lower beam 12;

rear cross member 2: a rear upper beam 21, a rear lower beam 22;

left side member 3: a left upper side member 31, a left lower side member 32;

the right longitudinal beam 4: a right upper side member 41 and a right lower side member 42;

and (5) flanging bracket: the bracket comprises a bracket body 51, a first flanging 52, a second flanging 53, a fuel tank contact part 501, a rear auxiliary frame abutting part 502 and an inclined part 503;

a fuel tank 100.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings.

It is easily understood that according to the technical solution of the present invention, those skilled in the art can substitute various structures and implementation manners without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as limiting or restricting the technical aspects of the present invention.

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like referred to or may be referred to in this specification are defined relative to the configuration shown in the drawings, and are relative terms, and thus may be changed correspondingly according to the position and the use state of the device. Therefore, these and other directional terms should not be construed as limiting terms.

In an embodiment of the invention, as shown in fig. 1, the rear subframe comprises a plurality of members, each member adopts a variable thickness structure formed by a rolling process, the rear subframe comprises a front cross beam 1, a rear cross beam 2, a left longitudinal beam 3 and a right longitudinal beam 4, the thicknesses of the front cross beam 1 and the rear cross beam 2 are reduced from the edge to the middle, the left longitudinal beam 3 and the right longitudinal beam 4 both comprise a rear subframe mounting point and a connecting rod mounting point, the rear subframe mounting point is used for being connected with the outside, the connecting rod mounting point is used for being welded with the front cross beam and the rear cross beam, and the thicknesses of the rear subframe mounting point and the connecting rod mounting point are thicker than those of other areas of the left.

Specifically, as shown in fig. 11, the thickness distribution of the front cross member 1 is divided into 6 regions from the overlapping region of the edges toward the middle, the thickness distribution of the rear cross member is divided into 5 regions from the overlapping region of the left and right edges toward the middle, and the thickness is reduced from the edges toward the middle. The left longitudinal beam 3 is divided into 7 areas from front to back according to the stress, and the right longitudinal beam 4 is symmetrical with the left longitudinal beam. The first region and the seventh region of the left trailing arm 3 from front to back are rear auxiliary frame mounting points, the second region, the third region and the fifth region are connecting rod mounting points, and the thickness is thicker; the first region and the seventh region from front to back of the left lower trailing arm relate to a rear auxiliary frame mounting point, the thickness is thicker, the other regions are relatively thinner, and the thickness distribution of the right trailing arm 4 is symmetrical with the thickness distribution.

Since the edge lap areas of the front cross member 1 and the rear cross member 2 are subjected to a large stress and a small stress in the middle, the thickness becomes thinner from the edge to the middle. And the left and right trailing

arms

3 and 4 need to bear larger stress at the rear subframe mounting point and the connecting rod mounting point, and the stress at other areas is smaller, so that the thickness of the rear subframe mounting point and the connecting rod mounting point is thicker than that of the other areas of the left and right longitudinal beams.

In the embodiment, the thickness of the part with high stress requirement of the rear auxiliary frame is increased, and the thickness of other parts is thinned, so that the requirement on structural strength is met, materials are saved, and the cost is reduced.

Alternatively, the thickness of each member is not limited to be divided into 5-7 regions, and other numbers of force-receiving regions may be divided according to the force received by each suspension form.

In one embodiment of the invention, as shown in fig. 1-3, a size optimization algorithm based on sensitivity is adopted for a variable thickness structure, and the thickness of each grid unit in a finite element model is preliminarily set according to a mechanical target to be borne by a corresponding position during design, so as to obtain the preliminary thickness; and then, based on the filter radius constraint, the thickness of a certain grid unit is related to the thickness of an adjacent grid unit to obtain a regionalized same-thickness design, so that the optimal thickness meeting the performance and the process simultaneously is obtained.

Specifically, as shown in fig. 1-2, in the present embodiment, the front cross member 1 further includes a front upper cross member 11 and a front lower cross member 12, the rear cross member 2 further includes a rear upper cross member 21 and a rear lower cross member 22, the left longitudinal member 3 includes a left upper longitudinal member 31 and a left lower longitudinal member 32, and the right longitudinal member 4 includes a right upper longitudinal member 41 and a right lower longitudinal member 42. A total of eight pieces are included, each of which can be formed by a roll process.

The rolling process enables the formation of a variable thickness structure for each piece of the member, and different portions of each piece of the member are subjected to different mechanical targets, so that the required sheet thicknesses for the different portions are different. Therefore, the thickness of the part needing to bear larger stress is designed to be thicker, and the thickness of the part needing to bear smaller stress is designed to be thinner, so that the requirement of structural strength can be met, the material is saved, and the cost is reduced.

In this embodiment, the thickness of each region of each member is designed according to the principle that the plate thickness corresponds to the stress to be borne, specifically as follows:

firstly, dividing a piece of component metal plate into a plurality of grid units by an integral finite element method, wherein the number of the grid units is n;

then, according to the stress born by each grid unit, a rigidity model under the minimum mass is established, and the preliminary thickness of each grid unit is respectively set as follows: t is t₁，t₂…t_nThe thickness value of the obtained preliminary thickness and the thickness value of the adjacent grid units are possibly greatly different, so that the manufacturing and processing are not facilitated;

and based on the filter radius constraint, the thickness of a certain grid unit is related to the thickness of the adjacent grid unit to obtain the optimal thickness. The filtering radius is centered on one of the grid cells and then a radius value is set. The circular area formed by the filtering radius is provided with adjacent grid units, the thickness of one grid unit is related to the thickness of the adjacent grid unit, the optimal thickness is obtained through adjustment, finally, the thicknesses of the adjacent grid units can be gradually changed in a transition mode, and the rolling process is facilitated to obtain the single-piece component.

The single-piece component obtained by the embodiment can meet the requirement of structural strength, saves materials, reduces the cost and is convenient to machine and form through a rolling process.

λ_i＝Max(O，r-dis(i，j))

where r is a preset filter radius, n is the number of grid cells, a distance coefficient λ, i represents an adjacent grid cell, j represents a target grid cell, dis (i, j) represents a distance between the adjacent grid cell and the target grid cell, and the distance coefficient λ is a value obtained by subtracting a distance between the adjacent grid cell and the target grid cell from the filter radius.

As shown in fig. 3, e is a circle center, r is a preset filtering radius, a gray circle represents an area where the filtering radius is located, the grid cells in the area are adjacent grid cells, the grid cell where e is located is a target grid cell, and the thicknesses of the target grid cells are related according to the thicknesses of the adjacent grid cells through the above formula, so as to obtain an optimal thickness.

Finally, the design that the middle of the front cross beam 1 and the middle of the rear cross beam 2 are thin and the two ends of the front cross beam 2 are thick can be obtained, the left longitudinal beam 3 and the right longitudinal beam 4 are thick at the installation points, and the other positions of the left longitudinal beam and the right longitudinal beam are thin.

In an embodiment of the invention, as shown in fig. 2, a front cross beam 1 is formed by welding a front upper cross beam 11 and a front lower cross beam 12, a rear cross beam 2 is formed by welding a rear upper cross beam 21 and a rear lower cross beam 22, a left longitudinal beam 3 is formed by welding a left upper longitudinal beam 31 and a left lower longitudinal beam 32, a right longitudinal beam 4 is formed by welding a right upper longitudinal beam 41 and a right lower longitudinal beam 42, then the left end and the right end of the front cross beam 1 are respectively welded with the left longitudinal beam 3 and the right longitudinal beam 4, and the left end and the right end of the rear cross beam 2 are respectively welded with the left longitudinal beam 3. After the main body part of the rear auxiliary frame is divided into eight pieces of components, each piece of component is a sheet metal part, and the processing and the manufacturing are convenient.

Alternatively, the main body portion of the rear subframe may also include other numbers of members, not limited to eight, but four, or six.

In one embodiment of the present invention, as shown in fig. 1 and 4, the rear cross member 2 includes a two-drive rear cross member and a four-drive rear cross member, and is replaced with a corresponding rear cross member according to the application of the rear sub frame.

Specifically, as shown in fig. 1, the rear cross member 2 in fig. 1 is a two-drive rear cross member, and the rear subframe is used for a two-drive vehicle type.

As shown in fig. 4, the rear cross member 2' in fig. 4 is a four-wheel drive rear cross member, and the rear sub frame is used for a four-wheel drive vehicle.

Because the rear auxiliary frame adopts the multi-piece component design, especially the rear cross beam 2 can be replaced by the component corresponding to different vehicle types, and other parts of the rear auxiliary frame do not need to be changed, thereby reducing the design and manufacturing cost.

As shown in fig. 5, the rear cross member 2 ' for the four-wheel drive includes a rear upper cross member 21 ' and a rear lower cross member 22 ', and the rear upper cross member 21 ' is connected to the rear lower cross member 22 ' by welding.

Alternatively, the lengths of the front cross member 1 and the rear cross member 2 can be changed without changing the left longitudinal member 3 and the right longitudinal member 4, so as to be used for designing different wheel tracks.

Further, the front cross beam 1, the rear cross beam 2, the left longitudinal beam 3 and the right longitudinal beam 4 comprise two welding seams, and the lengths of the two welding seams are equal.

Specifically, the front cross beam 1 is composed of a front upper cross beam 11 and a front lower cross beam 12, the front upper cross beam 11 and the front lower cross beam 12 are welded through two welding seams, the lengths of the two welding seams are equal, or the difference between the two welding seams is as small as possible, so that the deformation of the front cross beam 1 after welding can be reduced. The welding seam design of the rear cross beam 2, the left longitudinal beam 3 and the right longitudinal beam 4 is the same.

In one embodiment of the present invention, as shown in fig. 6 to 8, a flange bracket 5 is provided at the front side of the rear sub-frame, and the flange bracket 5 is used to contact the fuel tank 100.

Specifically, the burring bracket 5 is provided on the front side of the front cross member 1, and the oil tank 100 is arranged on the front side of the front cross member 1 of the vehicle body. The sharp punched edge of a conventional subframe is prone to puncture the fuel tank 100 during a collision.

The contact area between the flanging bracket 5 and the oil tank 100 is increased, the oil tank 100 is prevented from being punctured in collision, and the safety performance is improved.

Further, the contact length of the burring bracket 5 with the fuel tank 100 exceeds 12 mm.

Further, as shown in fig. 7, the burring bracket 5 includes a bracket body 51, a first burring 52 and a second burring 53, the first burring 52 and the second burring 53 are respectively located on the left and right sides of the bracket body 51, the first burring 52 and the second burring 53 are used for contacting with the oil tank 100, and the bracket body 51 is installed on the front side of the rear sub-frame.

The bracket body 51 is fixedly connected with the front cross beam 1 through bolts, and the first flange 52 and the second flange 53 are in contact with the oil tank 100, so that the contact area is increased, and the oil tank 100 is prevented from being punctured. The first flange 52 and the second flange 53 also increase the structural strength of the flange bracket 5, increasing durability.

Further, as shown in fig. 7, the first flange 52 and the second flange 53 include a tank contact portion 501 and a rear subframe abutting portion 502, the tank contact portion 501 extends in the vertical direction, and the rear subframe abutting portion 502 also extends in the vertical direction and abuts against the front end surface of the front cross member 1 of the rear subframe.

The first flange 52 and the second flange 53 are gradually bent upward from the front cross member 1 toward the oil tank 100, so that the oil tank contact portion 501 extends in the vertical direction, the oil tank contact portion 501 is in contact with the vertical surface of the oil tank 100, the projection areas of the two oil tank contact portions 501 on the oil tank 100 are a and B, the rear sub-frame abutting portion 502 also extends in the vertical direction and abuts against the front end surface of the front cross member 1 of the rear sub-frame, so that the structural strength is increased, and when a collision occurs, the collision force can be dispersed onto the front cross member 1. The tank contact portion 501 and the rear sub frame abutting portion 502 are transitionally connected by an inclined portion 503.

In one embodiment of the present invention, as shown in fig. 9-10, each sheet member is formed by blanking, and at least one pair of opposing side lines of each sheet member are parallel to each other.

Specifically, fig. 9 shows a left side member 3, and the left side member 3 includes a left upper side member 31 and a left lower side member 32. When the single left upper side member 31 is designed, two borderlines of the left upper side member 31 are designed to be substantially parallel to each other. As shown in fig. 10, when the sheet metal of the left upper longitudinal beam 31 is stamped, the distance between adjacent stamped parts can be small, and the material utilization rate is improved.

The design of other components is similar and will not be described in detail.

The invention is not limited to use with the rear sub-frame itself and can be applied to other chassis members as well.

The foregoing is considered as illustrative only of the principles and preferred embodiments of the invention. It should be noted that, for those skilled in the art, several other modifications can be made on the basis of the principle of the present invention, and the protection scope of the present invention should be regarded.

Claims

1. The utility model provides a back sub vehicle frame, its characterized in that includes the multi-disc component, every the component adopts the thickness of change structure that the roll-in technology formed, back sub vehicle frame includes front beam, back crossbeam, left longeron and right longeron, the front beam with the thickness of back crossbeam is by the thickness attenuation by the edge toward the middle part, left side longeron with right longeron all includes back sub vehicle frame mounting point and connecting rod mounting point, back sub vehicle frame mounting point is used for with external connection, the connecting rod mounting point be used for with the front beam with the back crossbeam welding, back sub vehicle frame mounting point with the thickness of connecting rod mounting point is thicker than the thickness in the other regions of left longeron and right longeron.

2. The rear subframe according to claim 1 wherein the variable thickness structure employs a sensitivity-based dimension optimization algorithm, and the thickness of each grid cell in the finite element model is preliminarily set according to a mechanical target to be borne by a corresponding position during design, and the preliminary thickness is obtained; and then, based on the filter radius constraint, the thickness of one grid unit is related to the thickness of the adjacent grid unit to obtain a regionalized same-thickness design, so that the optimal thickness meeting the performance and the process at the same time is obtained.

3. The rear subframe of claim 2 wherein said optimum thickness t of said grid cells is calculated according to the following equation:

λ_i＝Max(O，r-dis(i，j))

4. The rear subframe of claim 1 wherein said rear subframe comprises eight members, respectively a front top rail, a front bottom rail, a rear top rail, a rear bottom rail, a left top rail, a left bottom rail, a right top rail, and a right bottom rail, said front top rail and said front bottom rail together forming said front cross member, said rear top rail and said rear bottom rail together forming said rear cross member, said left top rail and said left bottom rail together forming said left side rail, and said right top rail and said right bottom rail together forming said right side rail.

5. The rear subframe of claim 1 wherein said rear cross member includes a two-drive rear cross member and a four-drive rear cross member, and wherein a corresponding rear cross member is replaced depending upon the application of said rear subframe.

6. The rear subframe of claim 1 wherein said front cross member, said rear cross member, said left side member and said right side member each include two weld seams, said weld seams being of equal length.

7. The rear subframe of claim 1 wherein said front side of said rear subframe is provided with a flange bracket for contacting a fuel tank.

8. The rear subframe according to claim 7, wherein the flange bracket comprises a bracket body, a first flange and a second flange, the first flange and the second flange are respectively positioned on the left side and the right side of the bracket body, the first flange and the second flange are used for contacting with the oil tank, and the bracket body is installed on the front side of the rear subframe.

9. The rear subframe of claim 8 wherein said first and second flanges include a tank contact portion extending in a vertical direction and a rear subframe abutment portion also extending in a vertical direction and abutting a front face of a front cross member of said rear subframe.

10. The rear subframe of claim 1 wherein each of said members is formed by blanking, and wherein at least one pair of opposing edge lines of each of said members are parallel to each other.