Vehicle structure

Abstract

To provide a vehicle structure that can improve steering stability easily and properly in comparison with a conventional vehicle structure, and has an excellent function of buffering impact caused at the time of a front collision of a vehicle.SOLUTION: In a vehicle structure A, a suspension member 5 is constituted in a nearly rectangular shape in a planar view, and arm front-side connection parts J1 connecting front portions of base end parts of lower arms 4 to the suspension member 5 are provided at both end parts in a vehicle width direction of a front-side frame member 50 of the suspension member 5 or at front parts of lateral-side frame members 52. In the front-side frame member 50, a portion Sa close to a center in the vehicle width direction is formed in a curved shape or a bent shape in a planar view, which protrudes toward a front side of a vehicle beyond both end parts in the vehicle width direction and the arm front-side connection parts J1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle structure such as an automobile, and more particularly to a structure around a mounting location of a suspension (front suspension) at the front of a vehicle. [Background technology]

[0002] A common vehicle front suspension structure is one in which suspension members are attached to a pair of left and right front side members, which are body structural members provided at the front of the vehicle, and lower arms are connected to the suspension members. The lower arms are members that support the front wheels at their distal ends (outer ends in the vehicle width direction). The front and rear base ends of the lower arms are rotatably connected to the suspension members via arm connectors that use rubber bushings or the like, so that the distal ends of the lower arms can swing up and down in the height direction, thereby lifting and lowering the front wheels. Here, as the suspension member, there is a means of using a member having a substantially rectangular frame shape (grid shape) in plan view, as described in, for example, Patent Documents 1 and 2. If the suspension member is formed in such a shape, it is possible to ensure a certain degree of strength while reducing the overall weight.

[0003] However, the above-mentioned prior art still has room for improvement, as will be described below. That is, when the vehicle is moving, the suspension member receives a force from the lower arm that is equivalent to the lateral force of the front wheel. If the suspension member is unable to adequately bear this force and is lacking in strength, the support of the lower arm becomes unstable, resulting in a deterioration in handling stability. Therefore, it is desirable to appropriately resolve this issue. On the other hand, when a vehicle frontal collision occurs, it is desirable to use a suspension member to efficiently absorb the collision energy as a means for mitigating the impact. In response to this, for example, in Patent Document 1, a portion of the suspension member is bent and deformed when a collision load is input, thereby absorbing the collision energy. However, if the vehicle is, for example, a cab-over vehicle, it is difficult to increase the crash stroke at the front of the vehicle, and it is difficult to sufficiently absorb the collision energy by bending and deforming the suspension member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-85473 [Patent Document 2] Japanese Patent Application Publication No. 11-129772 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention was conceived in light of the above-mentioned circumstances, and its object is to provide a vehicle structure that can easily and appropriately improve handling stability compared to conventional structures, and that also has excellent impact mitigation functions in the event of a frontal collision of the vehicle. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides the following technical solutions.

[0007] A vehicle structure provided by the present invention comprises a suspension member attached to a vehicle body constituent member at the front of the vehicle, and a pair of left and right lower arms, the front part of a base end of which on the inner side in the vehicle width direction is connected to the suspension member via an arm front connecting part, and the front wheels are attached to the tip parts on the outer side in the vehicle width direction, the mounting points of the front wheels being located rearward of the arm front connecting part, the suspension member having a generally rectangular frame shape in a plan view, the front and rear frame members extending in the vehicle width direction at a distance from each other in the vehicle front-rear direction, and a pair of left and right lateral frame members extending in the vehicle front-rear direction at a distance from each other in the vehicle width direction and connecting both end parts of the front and rear frame members in the vehicle width direction, the arm front connecting part being provided at both end parts in the vehicle width direction of the front frame member or in the front part of each lateral frame member, In a normal state, the base end of each lower arm is positioned higher than the tip end, and the lower arm is inclined when viewed from the front. a vehicle structure, wherein the front frame member has a curved or bent shape in a plan view, the portion of the front frame member near the center in the vehicle width direction protruding toward the front side of the vehicle beyond both ends in the vehicle width direction and the arm front connecting portion; and at least the lower surface portions of both ends of the front frame member in the vehicle width direction are inclined at an angle substantially equal to the inclination of each of the lower arms when viewed from the front. It is characterized by the presence of

[0008] This configuration provides the following effects. First, because the attachment point of the lower arm to the front wheel is located rearward of the arm front connector, which connects the front portion of the base end of the lower arm to the suspension member, when the vehicle is moving, the lateral force of the front wheel acts on the suspension member via the arm front connector as a pressing force inward in the vehicle width direction and diagonally forward. In response, the front frame member of the suspension member has a curved or bent shape in the direction in which the pressing force acts, or in a direction close to that direction, in a plan view. Therefore, the pressing force is effectively absorbed by the front frame member (which can prevent a large bending moment caused by the pressing force from being generated in the front frame member). As a result, the lower arm is stably supported, improving vehicle handling and stability. Secondly, when a frontal collision occurs and the collision load is input to the front of the suspension member, the front frame member, which had previously been protruding toward the front of the vehicle, deforms into a non-protruding shape, thereby absorbing the collision energy. Therefore, the collision energy can be absorbed without significantly deforming the entire suspension member, improving the impact mitigation function. This is an optimal effect for cab-over vehicles, where it is difficult to ensure a large crash stroke at the front of the vehicle. Thirdly, the above-mentioned effects are achieved by devising a new configuration for the front frame member of the suspension member, and the present invention does not require the use of special components or expensive equipment and components, which improves productivity and helps reduce the cost and weight of the vehicle.

[0009] In the present invention, preferably, the front frame member of the suspension member has inclined portions inclined with respect to the vehicle width direction in a plan view are provided on both outer sides of the portion closer to the center in the vehicle width direction so that the outer sides are positioned closer to the rear of the vehicle; and When a first load equal to or greater than a predetermined value is applied from the front side of the vehicle, the lateral frame members the front end of A second load can be input to the lateral frame members toward the outer side in the vehicle width direction and toward the diagonally rear side of the vehicle. The portion of the frame member that is closer to the front of the vehicle than the connecting portion with the rear frame member. At a midpoint in the vehicle longitudinal direction, each of the lateral frame members the front end of When the second load is input to Front-to-rear direction of the vehicle The intermediate portions serve as starting points for bending and deforming the lateral frame members so as to displace the intermediate portions outward in the vehicle width direction. As a part of sudden change in stiffness A rigid breaking point is provided.

[0010] With this configuration, in the event of a frontal collision of the vehicle, not only is the front frame member of the suspension member deformed by a first load input, but a second load is also input from the front frame member to the side frame member, causing the side frame member to actively bend and deform starting from the rigidity breaking point. This increases the amount of collision energy absorbed, making it possible to improve impact mitigation function and load-bearing performance. Because the bending deformation of the side frame member displaces intermediate portions of the side frame member outward in the vehicle width direction, it is also possible to appropriately prevent the side frame member from undue interference with other members located inward in the vehicle width direction.

[0011] Other features and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic bottom view of a main portion showing an example of a vehicle structure according to the present invention. [Figure 2] FIG. 2 is a schematic side view of a main part of the vehicle structure shown in FIG. [Figure 3] FIG. 3 is a schematic perspective view of a suspension member that constitutes the vehicle structure shown in FIGS. 1 and 2. [Figure 4] FIG. 4 is a schematic plan view of the suspension member shown in FIG. 3. [Figure 5] FIG. 4 is a schematic front view of the suspension member shown in FIG. 3. [Figure 6] FIG. 4 is a schematic bottom view of the suspension member shown in FIG. 3. [Figure 7] FIG. 2 is an explanatory diagram of the operation of the vehicle structure shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0014] 1 and 2 is applied to a cab-over type vehicle 1. An opening 20 for a so-called underfloor mounted power plant (not shown) is provided in a front floor portion 2 of the vehicle 1, and a seat riser and a seat portion (not shown) are provided above this opening 20.

[0015] The vehicle structure A includes a pair of left and right front side members 3 (shown in FIG. 1 with a dotted pattern), a pair of left and right lower arms 4 that form a front suspension FS and for suspending the front wheels 9, and a suspension member 5 (also called a subframe).

[0016] The pair of front side members 3 correspond to an example of the vehicle structural member referred to in the present invention, and extend in the longitudinal direction of the vehicle at a distance from each other in the vehicle width direction at the front of the vehicle. Each front side member 3 is, for example, a square pipe made of a metal member with a hat-shaped cross section. Reinforcing cross members 80a to 80d extending in the vehicle width direction are connected between the pair of front side members 3. A front bumper reinforcement 81 is connected to the front ends of the pair of front side members 3.

[0017] The lower arm 4 is a member that supports the front wheel 9 and has a base end portion, which is the inner portion in the vehicle width direction, that is rotatably supported by the suspension member 5 (see also Figures 3 to 6; the lower arm 4 is indicated by light ink in Figures 4 to 6). More specifically, the tip portion, which is the outer portion in the vehicle width direction of the lower arm 4, is provided with a mounting hole 48 for a joint member 49 (not shown in Figure 3) such as a ball joint, and a knuckle (not shown) for the front wheel is mounted to this portion to support the front wheel 9. The mounting hole 48 corresponds to an example of the "mounting location for the front wheel" as defined in the present invention.

[0018] An arm front coupling part J1 and an arm rear coupling part J2 are provided at the front and rear parts of the base end of the lower arm 4 to couple the lower arm 4 to the suspension member 5. These two coupling parts J1, J2 are formed using, for example, rubber bushings 47a, 47b, and the base end of the lower arm 4 is rotatably coupled to the suspension member 5 so that the tip end side of the lower arm 4 can swing up and down in the height direction around these two coupling parts J1, J2.

[0019] As shown in Figure 6, the front wheel mounting hole 48 of the lower arm 4 is located rearward of the arm front coupling part J1 by an appropriate distance La. Therefore, the lateral force LF acting on the front wheel 9 acts on the arm front coupling part J1 as a pressing force LF' directed diagonally forward and inward in the vehicle width direction.

[0020] The suspension member 5 has a generally rectangular frame shape in a plan view and includes a front frame member 50, a rear frame member 51, and a pair of left and right lateral frame members 52. The front frame member 50 and the rear frame member 51 are members that extend in the vehicle width direction at a distance in the vehicle fore-and-aft direction, and the pair of left and right lateral frame members 52 extend in the vehicle fore-and-aft direction at a distance in the vehicle width direction and connect both end portions of the front frame member 50 and the rear frame member 51 in the vehicle width direction. These members are connected to each other by, for example, welding. A steering gear box (not shown) is attached to the front frame member 50.

[0021] The suspension member 5 is fixedly attached to the undersides of the pair of front side members 3. As a means for this attachment, for example, an upwardly convex bracket portion 53 is provided on the upper surface of the front frame member 50, and a bolt fastening portion 54 having a bolt insertion hole is provided on the rear frame member 51. As shown in FIG. 2, the upper portion of the bracket portion 53 and the bolt fastening portion 54 are fastened to the undersides of the front side members 3 using bolts 88a, 88b.

[0022] Arm front coupling portions J1 are provided at both ends of the front frame member 50 in the vehicle width direction. Therefore, the aforementioned pressing force LF' acting on the arm front coupling portions J1 is input to the front frame member 50. In response to this, the front frame member 50 has a portion Sa (see FIG. 6) near the center in the vehicle width direction that is curved or bent in plan view and protrudes further toward the front of the vehicle than both ends in the vehicle width direction (and the arm front coupling portions J1). In this embodiment, inclined portions Sb that are inclined at an appropriate angle α1 with respect to the vehicle width direction are provided on both outer sides of the portion Sa near the center in the vehicle width direction, and preferably, this angle α1 approximately matches the inclination angle of the pressing force LF'. 2, reference numeral 18 denotes a dash panel that defines the front portion of the vehicle compartment. A portion Sa of the front frame member 50 near the center in the vehicle width direction protrudes further forward than the lower end of the dash panel 18.

[0023] 5, in the normal state, the base end of the lower arm 4 is positioned higher than the tip end, and the lower arm 4 is set to be inclined at an appropriate angle α2 when viewed from the front. In contrast, in the regions of the front frame member 50 near both ends in the vehicle width direction, at least the lower surface portions 50a thereof are inclined at an angle that is approximately equal to the angle α2 when viewed from the front.

[0024] The arm rear connection portion J2 of the lower arm 4 is provided at the rear end portion of the lateral frame member 52, and the rear frame member 51 is positioned on the upper surface of the rear end portion of the lateral frame member 52 so as to avoid interference with the arm rear connection portion J2.

[0025] A rigidity breaking point R is set at a midpoint in the vehicle longitudinal direction of the lateral frame member 52. This rigidity breaking point R is a location where the rigidity (bending strength) of the lateral frame member 52 suddenly changes, and is the starting point for causing bending deformation in the lateral frame member 52 when a load is input, as described later with reference to FIG. 7 . In this embodiment, a reinforcing member 6 made of metal and having a substantially rectangular plate shape is joined to the inside of the region near the front of the lateral frame member 52, and the rear end position of this reinforcing member 6, i.e., the boundary position between the location where the reinforcing member 6 is provided and the location where it is not provided, is set as the rigidity breaking point R. At the location of this rigidity breaking point R, the width dimension Lb of the lateral frame member 52 suddenly changes, and this sudden change in dimension also helps to set the rigidity breaking point R. Unlike this embodiment, it is also possible to set the rigidity breaking point R using only the sudden change in the width dimension Lb, without using the reinforcing member 6.

[0026] Next, the operation of the vehicle structure A will be described.

[0027] First, as described above, when the vehicle 1 is running, the pressing force LF' caused by the lateral force LF of the front wheel 9 is applied to the front frame member 50 of the suspension member 5 via the arm front connecting portion J1. The pressing force LF' acts on both ends of the front frame member 50. The direction of action of this pressing force LF' is inward and diagonally forward in the vehicle width direction, but the front frame member 50 is curved or bent so as to substantially coincide with the direction of action of the pressing force LF'. This makes it possible for the front frame member 50 to effectively absorb the pressing force LF' while preventing a large bending moment caused by the pressing force LF' from being generated in the front frame member 50. As a result, the lower arm 4 is stably supported, and the handling stability of the vehicle 1 can be improved.

[0028] 5, in the regions of the front frame member 50 near both ends in the vehicle width direction, at least the lower surface portions 50a thereof are inclined, in a front view, at an angle that substantially matches the inclination angle α2 of the lower arms 4. This allows the front frame member 50 to more effectively receive the pressing force LF' acting on the front frame member 50 from the lower arms 4.

[0029] On the other hand, when a frontal collision of the vehicle 1 occurs, as shown in FIG. 7, a first load F1 of a predetermined magnitude or greater may be applied to the front frame member 50 of the suspension member 5 from the front side of the vehicle. In response to this, the front frame member 50, which originally protrudes toward the front of the vehicle, is deformed into a non-protruding shape when the first load F1 is applied. This deformation can absorb the collision energy. This deformation of the front frame member 50 can preferably provide an impact absorbing function without unnecessarily deforming the entire suspension member 5. This is an optimal effect for a cab-over vehicle, where it is difficult to provide a large crash stroke at the front of the vehicle.

[0030] In the event of a frontal collision of the vehicle 1, when the first load F1 described above is input to the front frame member 50, a second load F2 is applied from the front frame member 50 to the front end of the lateral frame member 52, directed diagonally rearward and outward in the vehicle width direction. The larger the first load F1, the larger the second load F2 becomes, and when the second load F2 exceeds a predetermined value, the lateral frame member 52 undergoes bending deformation starting from the rigidity breaking point R. This bending deformation is in a direction that displaces the position of the rigidity breaking point R outward in the vehicle width direction. When such bending deformation occurs, the amount of collision energy absorbed increases, making it possible to further improve impact mitigation performance and impact resistance performance.

[0031] 2, the side frame member 52 of the suspension member 5 is inclined downward toward the front. Therefore, when the second load F2 acts on the side frame member 52 during a frontal collision of the vehicle 1, the bending deformation may be controlled so that the position of the rigidity breaking point R not only displaces outward in the vehicle width direction but also descends.

[0032] In the vehicle structure A of this embodiment, although improvements are made to the front frame member 50 and the side frame member 52 of the suspension member 5, no special and expensive parts or large additional parts are used, and the overall configuration can be simplified. Therefore, productivity is good, which is preferable in terms of reducing manufacturing costs and facilitating a reduction in vehicle weight.

[0033] The present invention is not limited to the above-described embodiment, and the specific configuration of each part of the vehicle structure according to the present invention can be freely modified in various ways within the intended scope of the present invention.

[0034] In the above-described embodiment, the arm front connecting portion J1 for connecting the front portion of the base end of the lower arm 4 to the suspension member 5 is provided at both ends of the front frame member 50 in the vehicle width direction, but this is not limited to this and the arm front connecting portion J1 may be configured to be provided at the front portion of the side frame member 52. The pressing force acting inward in the vehicle width direction from the arm rear connecting portion J2 of the lower arm 4 to the rear frame member 51 of the suspension member 5 is not very large. However, like the front frame member 50, the rear frame member 51 can also be formed into a curved or bent shape to accommodate the pressing force. As a means for setting a rigidity breaking point in the side frame member of the suspension member, in addition to or instead of the means of partially providing the reinforcing member and the means of changing the width dimension of the side frame member, it is also possible to use a means such as providing a thin-walled portion or a hole to make a part of the side frame member a partially weakened portion. The vehicle body structural members referred to in the present invention are not limited to a pair of left and right front side members, and the suspension member may be attached to a vehicle body structural member other than the front side members. The vehicle structure of the present invention is suitable for a cab-over vehicle, but is not limited to a specific type or model of the vehicle. It is of course also applicable to hybrid vehicles, electric vehicles, and the like. [Explanation of symbols]

[0035] A. Vehicle structure R rigidity point J1 Arm front connection 1 vehicle 3 Front side member (body component) 4 Lower Arm 48 Mounting hole (front wheel mounting point) 5 Suspension members 50 Front frame member 51 Rear frame member 52 Side frame member 9 Front wheels

Claims

1. a suspension member attached to a body structural member at the front of the vehicle; a pair of left and right lower arms, each having a front portion of a base end portion on an inner side in the vehicle width direction connected to the suspension member via an arm front connecting portion, and having a front wheel attached to a tip end portion on an outer side in the vehicle width direction, the attachment point of the front wheel being located rearward of the arm front connecting portion; It is equipped with the suspension member has a generally rectangular frame shape in a plan view, including a front frame member and a rear frame member extending in the vehicle width direction and spaced apart in the vehicle fore-and-aft direction, and a pair of left and right lateral frame members extending in the vehicle fore-and-aft direction and spaced apart in the vehicle width direction, and connecting both vehicle width direction end portions of the front frame member and the rear frame member, the arm front coupling portions are provided at both ends of the front frame member in the vehicle width direction or at the front portions of the lateral frame members, a vehicle structure in which, in a normal state, a base end portion of each lower arm is positioned higher than a tip end portion thereof, and the lower arm is in an inclined position when viewed from the front, a portion of the front frame member near the center in the vehicle width direction has a curved or bent shape in a plan view that protrudes toward the front of the vehicle further than both end portions in the vehicle width direction and the arm front coupling portion, a lower surface of each of the front frame member and the front frame member, the lower surface being inclined at an angle substantially equal to the angle of inclination of each of the lower arms, in a front view;

2. 2. The vehicle structure according to claim 1, the front frame members of the suspension member are provided with inclined portions inclined with respect to the vehicle width direction in a plan view on both outer sides of a portion closer to the center in the vehicle width direction so that the outer sides are positioned closer to the rear of the vehicle, and when a first load of a predetermined value or more is received from the front side of the vehicle, a second load directed outward in the vehicle width direction and diagonally rearward of the vehicle can be input to the front ends of the lateral frame members, A vehicle structure in which, at a midpoint in the vehicle longitudinal direction of each of the lateral frame members that is forward of the connection point with the rear frame member, a rigidity breaking point is provided as a location of sudden change in rigidity that serves as a starting point for bending deformation of each of the lateral frame members so as to displace the midpoint in the vehicle longitudinal direction outward in the vehicle width direction when the second load is input to the front end of each of the lateral frame members.

Images