Vehicle front structure

Abstract

To provide a vehicle front part structure that can appropriately cope with a collision load input into a region above a front side member and that can provide excellent impact absorption performance and load bearing performance increased more than ever before so as to decrease an occupant injury value as much as possible.SOLUTION: A vehicle front part structure A includes: a pair of left and right front side members 3 including compressive deformable portions 30A; subframes 6 disposed on a vehicle back side of a lower portion of a front fixation member 5 in a region below the pair of front side members 3; and rear fixation members 85 fixed on the vehicle back side of an upper portion of the front fixation member 5 in a region above the pair of front side members 3. A connection member 2 for absorbing collision energy, which serves as a bridge between the upper portion of the front fixation member 5 and the rear fixation member 85 to connect therebetween is provided on a predetermined position in the upper region above the front side member 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a front structure of a vehicle such as an automobile.

Background Art

[0002] The applicant of the present application has previously proposed, as an example of a vehicle front structure, the one described in Patent Document 1. In the vehicle front structure described in the same document, as vehicle body frame members at the front of the vehicle, a pair of left and right front side members are provided, and a region near the front ends of these pair of front side members is a compression deformation allowance portion when a frontal collision of the vehicle occurs. Further, a frame-shaped radiator support (front fixing member) is fixedly attached to a region near the front ends of the pair of front side members. Among the lower regions of the pair of front side members, a subframe (cradle) that deforms when a frontal collision of the vehicle occurs is further provided at a position rearward of the vehicle than the lower part of the radiator support.

[0003] According to such a configuration, when a frontal collision of the vehicle occurs and the collision load is input to the front part of the vehicle from the front side of the vehicle, this collision load is dispersed and transmitted to the front side members and the subframe. Further, the collision energy is absorbed by the deformation of each part. Therefore, it is possible to improve the shock absorption performance and load resistance performance (shock resistance performance) during a frontal collision of the vehicle.

[0004] However, in the above prior art, as described below, there are still problems to be improved.

[0005] First, when a frontal collision of the vehicle occurs, not only does the barrier (collision target) rush toward the front side members and the subframe below them, but it also rushes into a region above the front side members, and a collision load may be input. In contrast, in the above prior art, it is difficult to effectively receive such an input of a collision load to a region above the front side members. Second, when the collision load during a frontal collision of the vehicle is quite large, in the very early stage of the frontal collision of the vehicle, both the compression deformation allowance portion of the front side member and the subframe will collapse significantly in a very short time, making it difficult to withstand the collision load, and the load-bearing performance in the very early stage of the collision may be insufficient. When protecting the vehicle occupants with seat belts, it is desirable that the time required from the occurrence of the frontal collision of the vehicle until the vehicle speed becomes zero from the start of the occupant restraint operation by the seat belt be as long as possible. On the other hand, if the load-bearing performance in the very early stage of the collision is insufficient, the required time will be shortened, and there is a risk that the occupant injury values such as chest compression will deteriorate.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been conceived under the circumstances as described above, and can also preferably cope with the input of the collision load to the upper region of the front side member, and can minimize the occupant injury values as much as possible and it is an object of the present invention to provide a vehicle front structure that can be made to have excellent shock absorption performance and load-bearing performance, even better than the conventional ones.

Means for Solving the Problems

[0008] In order to solve the above problems, the present invention takes the following technical means.

[0009] The vehicle front structure provided by the present invention is, at the vehicle front, a pair of left and right front side members that extend in the vehicle longitudinal direction with a space therebetween in the vehicle width direction, and a compression deformation allowable portion in a region closer to the front end that undergoes compression deformation by the input of a collision load of a predetermined level or more when a vehicle frontal collision occurs; a front fixing member whose upper and lower portions respectively protrude above and below the pair of front side members and are fixedly attached to the region closer to the front end of the pair of front side members; a subframe that is fixedly provided on the vehicle rear side of the lower portion of the front fixing member in a region below the pair of front side members and that undergoes deformation when a vehicle frontal collision occurs and the lower portion of the front fixing member retreats; and a rear fixing member that is fixedly attached to the pair of front side members so as to be located on the vehicle rear side of the upper portion of the front fixing member in a region above the pair of front side members. The vehicle front structure further includes a connecting member for absorbing collision energy that is provided in an overlapping arrangement with at least a part thereof above the subframe in a view from the vehicle side in a region above the pair of front side members, bridges and connects the upper portion of the front fixing member and the rear fixing member, and undergoes deformation when a vehicle frontal collision occurs and the upper portion of the front fixing member retreats.

[0010] According to such a configuration, the following effects can be obtained. First, when a vehicle frontal collision occurs, in addition to being able to receive the collision load by the front side members and the subframe located below them as in Patent Document 1, for the collision load input (intrusion of the barrier) in the region above the front side members, it can be transmitted and received from the upper portion of the front fixing member to the rear fixing member via the connecting member for absorbing collision energy. At that time, it is possible to absorb the collision energy by deforming the connecting member. Thus, according to the present invention, it is possible to effectively receive the input of the collision load to the region above the front side members, and it is possible to improve the shock absorption performance and load resistance performance (impact resistance performance) compared with Patent Document 1. Second, at the very initial stage of a vehicle frontal collision, it is possible to effectively receive collision loads of different heights by each of a front side member, a subframe, and a connecting member for absorbing collision energy. Therefore, it is possible to appropriately avoid the insufficient load-bearing performance at the very initial stage of a vehicle frontal collision. As a result, it is possible to take a longer time from the occurrence of a vehicle frontal collision (the start of the occupant restraint operation by a seat belt) until the vehicle speed becomes zero than before, and prevent or suppress the deterioration of the occupant injury value due to chest compression or the like.

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

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

[0014] The vehicle front structure A shown in FIGS. 1 to 5 includes a pair of left and right front side members 3 provided at the front of the vehicle 1 (in FIGS. 1, 3, and 4, they are marked with a dot pattern), a radiator support 5, a suspension member 4, a pair of left and right sub-frames (cradles) 6, a moment canceller 85, and a connecting member 2 for absorbing collision energy. Here, the radiator support 5 and the moment canceller 85 respectively correspond to specific examples of the "front side fixing member" and the "rear side fixing member" in the present invention.

[0015] The vehicle front structure A of the present embodiment is characterized by the connecting member 2 for absorbing collision energy and related configurations, and the other configurations are the same as those in Patent Document 1. For the configurations that are the same as those in Patent Document 1, the description will be simplified.

[0016] The pair of front side members 3 have a pair of front portions 30 located on both sides in the vehicle width direction of the engine room 10 and extending in the vehicle front-rear direction. At the rear side of each front portion 30, a rearwardly downward inclined portion 31 and a substantially horizontal rearward extending portion 32 are sequentially connected. Although not shown in the figure, each front side member 3 is configured using, for example, a closed cross-section structural member with an internal cavity in the form of a hollow rectangular tube in cross-section or a similar form. In FIG. 1, reference numeral 12 indicates a dash panel that separates the engine room 10 and the passenger compartment 11, and reference numeral 13 indicates a floor panel.

[0017] The region near the front end of the front portion 30 is a compression deformation allowable portion 30A that undergoes compression deformation when a frontal collision of the vehicle 1 occurs and an input of a collision load equal to or greater than a predetermined value is applied. This compression deformation allowable portion 30A is configured such that a plurality of concave groove portions 33 (crash beads) extending in the vertical height direction, for example, are provided at appropriate intervals on the side surface portion of the front portion 30. When a frontal collision of the vehicle 1 occurs, it is compressed and deformed in a so-called bellows shape, and is more likely to undergo compression deformation than other regions of the front portion 30. Note that a front bumper reinforcement 80 extending in the vehicle width direction is mounted in a bridging manner between the front ends of the pair of front portions 30.

[0018] The suspension member 4 is located near the lower part of the rearwardly inclined portion 31 of the front side member 3 in a side view of the vehicle, extends in the vehicle width direction, and is supported by the front side member 3. At both ends of the suspension member 4 in the vehicle width direction, a lower arm 18 for supporting the front wheel 19 is attached, and a front attachment portion J1 and a rear attachment portion J2 for connecting to the front side member 3 are provided.

[0019] Here, the front attachment portion J1 has a configuration in which the upper part of an upright arm portion 41 provided upright upward in the front region of the suspension member 4 is fixedly connected to the front side member 3 via a support member 91 such as a bolt. The rear attachment portion J2 is a portion where the rear part of the suspension member 4 is fastened to the lower wall portion of a bracket portion 35 welded to the lower surface side of the rearwardly inclined portion 31 using a bolt 92. This rear attachment portion J2 also serves as a portion for connecting the rear part of the suspension member 4 to the front portion of a bracket portion 36 whose rear part is fixed to the rearward extension portion 32 using a bolt 95. The two bracket portions 35, 36, the rear part of the suspension member 4, and the rubber bush 18a at the base end portion of the lower arm 18 are fastened together by a bolt 92. In FIG. 4, reference numeral 17 indicates an outer torque box that bridgedly connects the rocker 16 and the front side member 3. Reference numeral 15 indicates a reinforcing member corresponding to an inner torque box. member.

[0020] The radiator support 5 includes a pair of left and right outer supports 50 joined to the front portions of the pair of front side members 3 and extending in the vertical height direction, and an upper support 52 and a lower support 51 bridgedly connected to the upper and lower ends thereof, respectively. A radiator 55 (appropriately omitted in the drawing) is placed on the lower support 51. A flat block-shaped crush box 53 that undergoes compressive deformation when a frontal collision of the vehicle 1 occurs and a compressive load of a predetermined value or more is received from the front side of the vehicle is provided at the lower part of the outer support 50.

[0021] The sub-frame 6 is configured using, for example, a square pipe-shaped member, and is provided in a position sandwiched between the crash box 53 and the suspension member 4 directly below the front portion 30 of the front side member 3 and extends in the vehicle front-rear direction. The rear end portion of the sub-frame 6 is connected to the front portion of the suspension member 4 via the connection portion J3. The connection portion J3 is configured such that the rear end portion of the sub-frame 6 enters an L-shaped extension portion 44 protruding from the front portion of the suspension member 4 as viewed from the side of the vehicle and is fixed using bolts 93.

[0022] The sub-frame 6 is formed in a V-shaped shape as viewed from the side of the vehicle, and an intermediate portion in the longitudinal direction of the vehicle in the front-rear direction is supported by the front side member 3 via the bracket 7 and the connection portion J4. The connection portion J4 is a portion where the upper surface portion of the sub-frame 6 is fastened to the lower portion of the bracket portion 7 using bolts 94. The upper portion of the bracket 7 is welded to the front side member 3 and is preferably located in the vicinity on the rearward side of the vehicle from the compression deformation allowance portion 30A.

[0023] The front end portion 60 of the sub-frame 6 is set to face and approach the crash box 53 with a gap therebetween. For this reason, when a frontal collision of the vehicle 1 occurs and the crash box 53 retreats by a predetermined distance or more, the sub-frame 6 receives a pressing force (collision force) from the crash box 53 toward the rear side of the vehicle and deforms. Note that the sub-frame 6 is not limited to the V-shaped shape as viewed from the side, and may be, for example, in a form extending substantially straight in the horizontal direction. In the present embodiment, the front end portion 60 is a free end not connected to any portion of the radiator support 5, but alternatively, for example, the front end portion 60 may be configured to be in contact with and connected to the crash box 53.

[0024] The moment canceler 85 is essentially a part for canceling the moment that tries to bend the front side member 3 upward when a frontal collision of the vehicle 1 occurs and there is a load input from the front side of the vehicle, and improving the impact absorption performance of the vehicle 1 by promoting the compression deformation of the front side member 3 (compression deformation allowance portion 30A). This moment canceler 85 is a panel-shaped member whose lower part is connected to the rear part of the compression deformation allowance portion 30A of the front side member 3 in the vehicle height direction and stands upright. The rear part of this moment canceler 85 is joined to a vehicle body component such as a cowl side panel (not shown). A suspension tower 88 (see FIG. 3) is provided inside the moment canceler 85 in the vehicle width direction.

[0025] The connecting member 2 for absorbing collision energy is, for example, a bar-shaped member made of metal, and is provided so as to bridge-connect the upper part of the outer support 50 and the frontward portion of the moment canceler 85 in the upper region of each front side member 3. Further, at least a part of the connecting member 2 is arranged to overlap the upper side of the sub-frame 6 in a side view of the vehicle. Front brackets 25 and rear brackets 26 are joined to the front end portion and the rear end portion of the connecting member 2 (see also FIG. 5), and these front brackets 25 and rear brackets 26 are bolted or welded to the outer support 50 and the moment canceler 85, whereby the connecting member 2 is attached. is achieved.

[0026] The connecting member 2 is straight when viewed from the side of the vehicle. However, in plan view, the forward region 20a and the rearward region 20b of this connecting member 2 are straight and extend in the longitudinal direction of the vehicle, while the intermediate region 20c is straight and extends obliquely, and it is a bent bar having two front and rear bending portions 21a, 21b (see FIG. 5). For this reason, when a frontal collision of the vehicle 1 occurs and the connecting member 2 receives a collision load from the front side of the vehicle, while generating a resistance force against this collision load (a tension force against the rearward movement of the upper part of the outer support 50), bending deformation occurs starting from the positions of the bending portions 21a, 21b, and an energy absorption function is exhibited. Preferably, the bending deformation of the connecting member 2 as described above is configured to end at the same timing as the end of the compression deformation of the compression deformation allowable portion 30A of the front side member 3 when a frontal collision of the vehicle 1 occurs.

[0027] Next, the operation of the vehicle front structure A described above will be explained.

[0028] In the normal state where no frontal collision of the vehicle 1 has occurred, since the upper part of the radiator support 5 and the moment canceller 85 are connected via the connecting member 2, the rigidity of this series of parts is increased. Further, since a subframe 6 supported by the front side member 3 via a bracket 7 is connected to the front side of the suspension member 4, the rigidity of this series of parts is also increased, and the suspension member 4 can be stabilized.

[0029] When a frontal collision of the vehicle 1 occurs and there is an input of a collision load greater than a predetermined value to the front part of the vehicle 1 from the front side of the vehicle, a part of this collision load is input to and received by the front side member 3, and the compression deformation allowable portion 30A undergoes compression deformation. Also, another part of the collision load is input to and received by the subframe 6 via the crush box 53 of the radiator support 5, and this subframe 6 also deforms. Further, another part of the collision load is input to and received by the connecting member 2 from the upper part of the radiator support 5, and this connecting member 2 also deforms.

[0030] FIG. 6 shows an example in the case where the above-described compression deformation allowance portion 30A, sub-frame 6, and connecting member 2 are greatly deformed due to the above-described collision load (corresponding to the middle and late stages of a collision). Due to the deformation of each part in this way, the collision energy is appropriately absorbed, and the impact received by the occupant is mitigated. According to the vehicle front structure A of the present embodiment, it is possible to cause the connecting member 2 to receive the collision load acting on the region above the front side member 3 and appropriately absorb the energy thereof. Further, it is also possible to cause load transmission to the moment canceler 85. Therefore, it is possible to improve the impact absorption performance and load resistance performance (impact resistance performance).

[0031] On the other hand, even at the very initial stage of a frontal collision of the vehicle 1, it is possible for the front side member 3, sub-frame 6, and connecting member 2 to appropriately receive collision loads having different heights. For this reason, it is possible to appropriately avoid the load resistance performance at the very initial stage of a frontal collision of the vehicle 1 from becoming insufficient. As a result, from the time when a frontal collision of the vehicle 1 occurs and the occupant restraint operation is started by the seat belt until the vehicle speed becomes zero, it is possible to take a relatively long time. As a result, it is possible to prevent or suppress the deterioration of the injury value due to chest compression of the occupant or the like.

[0032] In FIG. 6(b), the connecting member 2 is bent and deformed in a substantially Z shape, and this bending deformation is such that the bent portion 21a is located on the rear side of the vehicle with respect to the bent portion 21b, and the amount of deformation thereof is large and is preferable. However, more preferably, when the compression deformation over substantially the entire length range of the compression deformation allowance portion 30A of the front side member 3 is completed due to the collision load, the connecting member 2 is configured to be in the state shown by the virtual line in FIG. 7. That is, in the mode indicated by the phantom line in FIG. 7, the bent portions 21a and 21b of the connecting member 2 are at substantially the same position in the vehicle longitudinal direction, and the intermediate region 20c extends at an angle in the vehicle width direction. The connecting member 2 generates a tension force against a collision load from the front side of the vehicle. However, if the connecting member 2 is configured to deform from the mode indicated by the solid line in FIG. 7 to the mode indicated by the phantom line, it is possible to effectively generate a tension force against the collision load (when the intermediate region 20c and the bent portion 21a of the connecting member 2 are displaced further to the rear side of the vehicle (the right side in the figure) than the position indicated by the phantom line in FIG. 7, during that period, it is difficult to generate an effective tension force against the collision load).

[0033] The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each part of the vehicle front structure according to the present invention can be variously designed and changed within the scope intended by the present invention.

[0034] The connecting member for absorbing collision energy is not limited to the bent bar-shaped one having the two bent portions 21a and 21b of the above-described embodiment. For example, it may be a straight bar shape, a curved bar shape, etc., and may also be in a form other than the bar shape (such as a plate shape). Further, instead of or in addition to forming a bent portion at a midpoint in the longitudinal direction of the connecting member, a rigid break point provided with a through hole, a weak portion, etc. may be set, and when a collision load is input, a configuration may be adopted in which the connecting member is bent and deformed starting from the rigid break point.

[0035] The front side members may be provided in a pair on the left and right at intervals in the vehicle width direction at the front part of the vehicle, and each may have a configuration extending in the vehicle longitudinal direction, and the specific shape thereof is not limited. In addition, the compression deformation allowance portion provided in the region near the front end of each front side member may be configured to cause compression deformation by input of a collision load of a predetermined level or more when a frontal collision of the vehicle occurs, and again, the specific configuration thereof is not limited.

[0036] The front fixing member is not limited to the radiator support, and may be, for example, a front bulkhead. However, the front fixing member is preferably a frame-shaped body. Here, the frame-shaped body corresponds to a member including a pair of left and right columnar portions that are joined to the front portions of a pair of left and right front side members and stand upright in the vertical height, and at least one member (cross member) that extends in the vehicle width direction so as to bridge between these pair of columnar portions. Unlike the above-described embodiment, a crash box may not be provided at the lower portion of the front fixing member. The rear fixing member is not limited to the moment canceller of the above-described embodiment, and other members may be used. The subframe is not limited to a U-shaped form in side view, and may be, for example, a straight shape having no bent portion, or a bent shape different from the U-shape.

[0037] The vehicle front structure of the present invention is not limited to engine vehicles, and can of course be applied to hybrid vehicles and electric vehicles.

Explanation of Reference Numerals

[0038] A Vehicle front structure 1 Vehicle 2 Connecting member 3 Front side member 30A Compression deformation allowable portion 4 Suspension member 5 Radiator support (front fixing member) 6 Subframe 85 Moment canceller (rear fixing member)

Claims

[Claim 1] a pair of left and right front side members at a front portion of the vehicle, the front side members extending in a longitudinal direction of the vehicle and spaced apart from each other in a vehicle width direction, and the front end regions of the front side members being compressive deformation allowable portions that undergo compressive deformation when a collision load equal to or greater than a predetermined value is input in the event of a frontal collision of the vehicle; a front fixing member fixedly attached to a region near the front ends of the pair of front side members such that an upper portion and a lower portion of the front fixing member protrude upward and downward from the pair of front side members, respectively; a subframe that is fixed to a vehicle rear side of a lower portion of the front fixing member in a region below the pair of front side members and that deforms when a frontal collision of the vehicle occurs and the lower portion of the front fixing member moves backward; a rear fixing member fixed to the pair of front side members so as to be located rearward of the vehicle relative to an upper portion of the front fixing member in an area above the pair of front side members; A vehicle front structure comprising: a connecting member for absorbing collision energy, the connecting member being provided in an area above the pair of front side members, at least a part of which is arranged to overlap an upper side of the subframe in a side view of the vehicle, the connecting member bridgingly connecting an upper part of the front fixing member and the rear fixing member, and the connecting member being deformed when a frontal collision of the vehicle occurs and the upper part of the front fixing member moves backward, The connecting member is When viewed from the side of the vehicle, the vehicle is straight and extends in a horizontal direction, A vehicle front structure characterized in that, in a plan view, the front and rear regions are straight and extend in the fore-and-aft direction of the vehicle, while the middle region is straight and extends at an angle with respect to the fore-and-aft direction of the vehicle, and the boundaries between each of the front and rear regions and the middle region are configured as bent bars with two bent portions at the front and rear.

Images