Suspension cross member mounting structure

Abstract

A suspension cross member mounting structure 1 comprises: a suspension cross member 2 of which both outer sides in a vehicle width direction are supported by a pair of left and right side members 5 extending in the longitudinal direction of a vehicle; a lower arm 3 of which one side in the vehicle width direction is connected to the suspension cross member 2 at two front and rear connection parts, which are a front-side connection part 3a and a rear-side connection part 3b, the other side being connected to a front wheel 6; and a stay member 4 that connects the suspension cross member 2 and the side members 5 on both outer sides of the suspension cross member 2 in the vehicle width direction, and that has a first fastening part F1 and a second fastening part F2 fastened to the suspension cross member 2, and a third fastening part F3 fastened to the side members 5. The first fastening part F1 and second fastening part F2 of the stay member 4 are fastened to the suspension cross member 2 at positions on both sides in the vehicle width direction with respect to connection points G between the rear side connection part 3b of the lower arm 3 and the suspension cross members 5, and the third fastening part F3 is fastened to the side members 5 behind the suspension cross member 2.

Description

Suspension cross member mounting structure

[0001] The present invention relates to a suspension cross member mounting structure.

[0002] The suspension cross member is a component that supports the suspension mechanism of a vehicle. It is bolted to each of the side members on both sides of the vehicle width direction and is connected to the wheels via lower arms. In this case, each lower arm on both sides of the vehicle width direction is generally connected to the suspension cross member at two points in the front-to-rear direction of the vehicle, as disclosed in Patent Document 1, for example.

[0003] More specifically, the conventional technology of Patent Document 1 discloses a configuration in which a bifurcated lower arm that supports the front wheels of a vehicle is connected to a front connecting portion and a rear connecting portion on both sides of the suspension cross member in the vehicle width direction, and proposes a structure in particular to improve the durability of the front connecting portion.

[0004] JP 2011-093348 A

[0005] In the event of a frontal collision, the load acting on the vehicle is input to the suspension cross member via the lower arm. Therefore, unless the suspension cross member efficiently transmits the load to frame members such as the side members, it will be unable to reduce the amount of vehicle body deformation, which could impair occupant protection. However, if the design specifications of the suspension mechanism and its peripheral components impose restrictions on the connection between the side members and lower arm and the suspension cross member, it may become impossible to adopt a configuration that is advantageous for efficient load transmission.

[0006] The present invention was made in consideration of such problems, and its purpose is to provide a suspension cross member mounting structure that can reduce the amount of vehicle body deformation in the suspension cross member during a frontal collision of the vehicle.

[0007] In order to achieve the above-mentioned object, the suspension cross member mounting structure of the present invention comprises a suspension cross member whose both outer sides in the vehicle width direction are supported by a pair of left and right side members extending in the fore-and-aft direction of the vehicle, a lower arm whose one side in the vehicle width direction is connected to the suspension cross member at two front and rear connection parts, a front connection part and a rear connection part, and whose other side is connected to a wheel, and a stay member which connects the suspension cross member to the side members on both outer sides in the vehicle width direction of the suspension cross member, and which has a first fastening part and a second fastening part which are fastened to the suspension cross member, and a third fastening part which is fastened to the side member, wherein the first fastening part and the second fastening part of the stay member are fastened to the suspension cross member at positions on both sides in the vehicle width direction of the connection point between the rear connection part of the lower arm and the suspension cross member, and the third fastening part is fastened to the side member rearward of the suspension cross member.

[0008] In the suspension cross member mounting structure of the present invention, stay members that span and connect the suspension cross member and side member are fastened to the suspension cross member at positions on both sides of the connection point between one end of the lower arm and the suspension cross member in the vehicle width direction, thereby distributing the load input to the connection point during a frontal collision of the vehicle and transmitting it to the side member. Therefore, according to the present invention, by providing the stay members, deformation of the suspension cross member can be suppressed in the event of a frontal collision of the vehicle, thereby reducing vehicle body deformation.

[0009] The present invention relates to a suspension cross member mounting structure and a suspension cross member mounting structure, and more particularly to a suspension cross member mounting structure according to the present invention.

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the contents described below, and can be implemented with any modifications within the scope that does not change the gist of the disclosure. Furthermore, all drawings used to explain the embodiments are schematic representations of components, and may be partially emphasized, enlarged, reduced, or omitted to facilitate understanding, and may not accurately represent the scale, shape, etc. of the components.

[0011] In addition, in each drawing used to explain the embodiments, the front of the vehicle is represented by Fr, the rear of the vehicle by Re, the left side of the vehicle by Le, and the right side of the vehicle by Ri, so that the front-to-rear direction, left-to-right direction (vehicle width direction), and vehicle height direction of the vehicle can each be identified.

[0012] Figure 1 is a bottom view of a suspension cross member mounting structure 1. More specifically, Figure 1 shows the components of the suspension cross member mounting structure 1 when the front portion of a vehicle to which the present invention is applied is viewed from below in the vehicle height direction. The suspension cross member mounting structure 1 according to the present invention comprises a suspension cross member 2, a pair of lower arms 3, and a pair of stay members 4, and is mounted below, in the vehicle height direction, side members 5 that constitute the vehicle's frame members.

[0013] Here, the side members 5 in this embodiment are a pair of left and right frames extending in the front-to-rear direction of the vehicle, and include a front side member 5a located below the engine compartment, a floor side member 5b located below the passenger compartment, and an inner extension 5c and an outer extension 5d branching off from the floor side member 5b. The front side member 5a is located in front of and above the floor side member 5b and is connected to the floor side member 5b along a smoothly curved path. The side members 5 also have a branching portion Br in front of the floor side member 5b, and the inner extension 5c and the outer extension 5d branch off from the branching portion Br to the inside and outside in the vehicle width direction, respectively, and extend toward the rear of the vehicle.

[0014] The suspension cross member 2 supports the vehicle suspension mechanism (not shown), and is supported on both outer sides in the vehicle width direction by a pair of left and right side members 5. The suspension cross member 2 is also fixed to the front side members 5a via connecting parts (not shown) that protrude upward in the vehicle height direction from the top surface.

[0015] The pair of lower arms 3 are arm-shaped members to which shock absorbers and bump stoppers (neither of which are shown) are attached. Each lower arm 3 is connected to the suspension cross member 2 at one end in the vehicle width direction at two connecting portions, a front connecting portion 3a and a rear connecting portion 3b, at the front and rear ends of the suspension cross member 2, and connected to the front wheels 6 at the wheel connecting portion 3c on the other end.

[0016] The pair of stay members 4 are reinforcing members made of sheet metal that are fastened to the suspension cross member 2 and the side member 5 on both outer sides of the suspension cross member in the vehicle width direction, and are configured to efficiently transmit the load input from the lower arm 3 to the suspension cross member 2 to the side member 5 in the event of a frontal collision of the vehicle, as will be described in detail below.

[0017] Next, we will explain the connection between the components of the suspension cross member mounting structure 1. Figure 2 is a partially enlarged, see-through view of the connection between the lower arm 3 and the suspension cross member 2. The suspension cross member 2 includes an upper plate that forms the top surface and a lower plate that forms the bottom surface, and is formed hollow by welding together bent flanges formed on the periphery of each plate by three-dimensional molding.

[0018] The lower arm 3 is positioned in the rear region of the suspension cross member 2 so that the rear connecting portion 3b is inserted between the upper plate and the lower plate, and is bolted integrally to the suspension cross member 2 at connecting point G.

[0019] The stay member 4 has high rigidity due to three-dimensional molding in which a bent flange is formed on the periphery of the sheet metal member, and is positioned so as to straddle a portion of the periphery in the rear region of the suspension cross member 2. The stay member 4 is bolted to the suspension cross member 2 and the side member 5 at the first fastening portion F1, bolted to the suspension cross member 2 at the second fastening portion F2, and bolted to the side member 5 (not shown in FIG. 2 ) at the third fastening portion F3. In other words, the suspension cross member 2 has a cross-member fastening portion that is fastened to the side member 5, and the first fastening portion F1 of the stay member 4 is fastened to the side member 5 together with the cross-member fastening portion, thereby fastening the stay member 4 and the suspension cross member 2 together to the side member 5. The third fastening portion F3 of the stay member 4 is fastened to the side member 5 rearward of the suspension cross member 2. The stay member 4 is not limited to being made of sheet metal as described above, and may be made of, for example, a cast or forged metal material.

[0020] Here, the stay member 4 of this embodiment has an approximate triangular shape when viewed in a plane, including the first fastening portion F1, the second fastening portion F2, and the third fastening portion F3, and is formed in a shape that exposes the connection point G so as not to interfere with the bolt removal and attachment operations at the connection point G.

[0021] Next, the problems of the conventional technology will be explained. Figure 3 is a schematic diagram showing the state of vehicle body deformation caused by a frontal collision of a vehicle according to the conventional technology. More specifically, Figure 3 shows the state of deformation after a vehicle collision for a suspension cross member 2 that does not include the stay member 4 described above. Here, the suspension cross member mounting structure according to the conventional technology is assumed to have the same configuration as the present invention except for the stay member 4, and the same reference numerals will be used to designate the same components as those of the present invention, and detailed explanations will be omitted.

[0022] Depending on the design specifications of the suspension mechanism and its surrounding components installed in a vehicle, the connection configuration between the side member 5 and lower arm 3 and the suspension cross member 2 may be restricted, and it may not be possible to efficiently transmit the load in the event of a frontal collision of the vehicle to skeletal components such as the side member 5 to absorb the impact.

[0023] In such a case, for example, when a load is applied to the lower arm 3 from the front of the vehicle, the lower arm 3 transmits the load to the suspension cross member 2 so that the rear connecting portion 3b pushes into the rear region of the suspension cross member 2 as shown in Figure 3, displacing the position of the original connecting point G to the position indicated by point G'. At this time, the rear region of the suspension cross member 2 cannot transmit the load to the side member 5, and is crushed so that it is wrapped around the bolt fastening portion N (i.e., the position corresponding to the first fastening portion F1 described above) that is fastened to the side member 5.

[0024] In other words, in vehicles using conventional technology, depending on the surrounding configuration of the suspension cross member 2, the impact caused by a frontal collision of the vehicle may not be absorbed, and the amount of body deformation starting from the suspension cross member 2 may not be suppressed, which could potentially hinder occupant protection.

[0025] In contrast, the suspension cross member mounting structure 1 of the present invention is equipped with a stay member 4 as a reinforcing member, and as described below, its fastening configuration efficiently transmits and absorbs the load caused by a frontal collision to the side member 5.

[0026] 4 is a schematic diagram showing load transmission in the suspension cross member mounting structure 1 according to the present invention. In the suspension cross member mounting structure 1, the stay member 4 has a first fastening portion F1 and a second fastening portion F2 located on either side of the connection point G between the rear connecting portion 3b of the lower arm 3 and the suspension cross member 2 in the vehicle width direction, and is fastened to the suspension cross member 2 with an imaginary line connecting the first fastening portion F1 and the second fastening portion F2 crossing the connection point G as the rear connecting portion 3b. In other words, the first fastening portion F1 and the second fastening portion F2 are located on either side of the connection point G in the vehicle width direction. Therefore, the load Lg input from the lower arm 3 to the connection point G is transmitted not only to the rear region of the suspension cross member 2 but also to the stay member 4 via the first fastening portion F1 and the second fastening portion F2.

[0027] At this time, a portion of the load Lg is transmitted directly from the suspension cross member 2 to the side member 5 at the first fastening portion F1, and is also transmitted in a dispersed manner on the stay member 4 as load L1 from the first fastening portion F1 to the third fastening portion F3 and load L2 from the second fastening portion F2 to the third fastening portion F3, and is then transmitted from the third fastening portion F3 to the side member 5 as load L3.

[0028] In addition, the stay member 4 can reinforce the connection between the suspension cross member 2 and the side member 5 at the first fastening portion F1, so that the collision load can be transmitted more efficiently to the side member 5. Furthermore, the stay member 4 can serve as a single member to both reinforce the first fastening portion F1 and reinforce the connection point G between the lower arm 3 and the suspension cross member 2.

[0029] Therefore, the rear region of the suspension cross member 2 is reinforced by the stay member 4, and the load Lg input from the lower arm 3 via the connection point G can be distributed to multiple paths in cooperation with the stay member 4 and transmitted to the side member 5, thereby suppressing the amount of vehicle body deformation in a frontal collision. In addition, the suspension cross member mounting structure 1 as a whole suppresses vibration of the front wheels 6 when the vehicle is running, which can also improve the vehicle's handling stability in normal conditions.

[0030] Furthermore, since the stay member 4 is fastened to the side member 5 so that the first fastening portion F1 and the third fastening portion F3 are arranged side by side in the fore-and-aft direction of the vehicle, the load from the front of the vehicle during a frontal collision can be efficiently transmitted toward the rear of the vehicle along the extension direction of the side member 5.

[0031] 4, the stay member 4 may be set so that the imaginary line connecting the first fastening portion F1 and the second fastening portion F2 is located rearward of the connecting point G in the vehicle longitudinal direction. In this case, the stay member 4 can efficiently support the connecting point G from the rear so that the rear region of the suspension cross member 2 is not pushed in by the load Lg input from the lower arm 3 to the connecting point G.

[0032] The stay member 4 also has a first side S1 parallel to an imaginary line segment (not shown) connecting the first fastening portion F1 and the third fastening portion F3, and a second side S2 parallel to an imaginary line segment (not shown) connecting the second fastening portion F2 and the third fastening portion F3. This allows the load input from the lower arm 3 to be efficiently transmitted from the first fastening portion F1 and the second fastening portion F2 to the third fastening portion F3 via the first side S1 and the second side S2, which are the shape of the stay member 4.

[0033] Furthermore, the first fastening portion F1 and the second fastening portion F2 are set to be positioned at approximately the same distance from the connection point G, so that the impact transmitted to the stay member 4 can be distributed approximately evenly.

[0034] Furthermore, by setting the third fastening portion F3 at the branch portion Br of the side member 5, the stay member 4 can distribute the load L3 transmitted from the third fastening portion F3 to the side member 5 to multiple branch destinations.

[0035] Furthermore, since the stay member 4 in the present invention is arranged to cover a portion of the rear region of the suspension cross member 2 from below in the vehicle height direction, the risk of the suspension cross member 2 being deformed downward in the vehicle height direction due to the load Lg input to the connection point G via the lower arm 3 can be reduced.

[0036] As described above, in the suspension cross member mounting structure 1 according to the present invention, the stay members 4 that connect across the suspension cross member 2 and the side members 5 are fastened to the suspension cross member 2 at positions on both sides of the connection point G between the rear connecting portion 3b of the lower arm 3 and the suspension cross member 2 in the vehicle width direction, thereby dispersing the load Lg that is input to the connection point G during a frontal collision of the vehicle and transmitting it to the side members 5. Therefore, in accordance with the suspension cross member mounting structure 1, by providing the stay members 4, deformation of the suspension cross member can be suppressed during a frontal collision of the vehicle, thereby reducing vehicle body deformation.

[0037] REFERENCE SIGNS LIST 1 Suspension cross member mounting structure 2 Suspension cross member 3 Lower arm 3a Front connecting portion 3b Rear connecting portion 3c Wheel connecting portion 4 Stay member 5 Side member 5a Front side member 5b Floor side member 5c Inner extension 5d Outer extension 6 Front wheel G Connecting point N Bolt fastening portion Br Branch portion F1 First fastening portion F2 Second fastening portion F3 Third fastening portion S1 First side edge S2 Second side edge

Claims

1. A suspension cross member mounting structure comprising: a suspension cross member whose outer sides in the vehicle width direction are supported by a pair of left and right side members extending in the fore-and-aft direction of the vehicle; a lower arm whose one side in the vehicle width direction is connected to the suspension cross member at two front and rear connection parts, a front connection part and a rear connection part, and whose other side is connected to a wheel; and a stay member which connects the suspension cross member to the side members on both outer sides in the vehicle width direction of the suspension cross member, and which has a first fastening part and a second fastening part which are fastened to the suspension cross member, and a third fastening part which is fastened to the side member, wherein the first fastening part and the second fastening part of the stay member are fastened to the suspension cross member at positions on either side of the connection point between the rear connection part of the lower arm and the suspension cross member in the vehicle width direction, and the third fastening part is fastened to the side member rearward of the suspension cross member.

2. A suspension cross member mounting structure as described in claim 1, wherein the first fastening portion is fastened to the suspension cross member on the vehicle widthwise outer side of the connection point, and the stay member is fastened to the suspension cross member and the side member so that the first fastening portion and the third fastening portion are arranged side by side in the fore-and-aft direction of the vehicle.

3. A suspension cross member mounting structure as described in claim 1 or 2, wherein an imaginary line segment connecting the first fastening portion and the second fastening portion is located rearward of the connection point.

4. A suspension cross member mounting structure as set forth in any one of claims 1 to 3, wherein the first fastening portion and the second fastening portion are positioned approximately equidistant from the connection point.

5. A suspension cross member mounting structure as described in any one of claims 1 to 4, wherein the stay member has a first side edge parallel to an imaginary line segment connecting the first fastening portion and the third fastening portion, and a second side edge parallel to an imaginary line segment connecting the second fastening portion and the third fastening portion.

6. A suspension cross member mounting structure as described in any one of claims 1 to 4, wherein the side member has a branch portion that branches into multiple parts, and the third fastening portion of the stay member is fastened at the branch portion.

7. A suspension cross member mounting structure as described in any one of claims 1 to 6, wherein the stay member covers at least the portion of the suspension cross member rearward of the connection point from below.

8. A suspension cross member mounting structure as set forth in claim 7, wherein the stay member is shaped to expose the connection point.

9. A suspension cross member mounting structure as described in any one of claims 1 to 8, wherein the suspension cross member has a cross member fastening portion that is fastened to the side member, and the stay member has the first fastening portion that is fastened to the side member together with the cross member fastening portion.

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