JP2008213562A - Vehicle body front part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide vehicle body front structure capable of obtaining a desired load transmission behavior or deformation behavior while surely setting rigidity difference in the longitudinal direction of a front side frame in the vehicle body front part structure equipped with a pair of right and left front side frames extending to the longitudinal direction of the vehicle body. <P>SOLUTION: A recessed groove 60 extending from the intermediate position in the longitudinal direction toward the rear side is formed on the inner side surface of the front side frame 1. The closed cross section in the front side frame 1 is sequentially increased from the vehicle body front part toward the rear part side by fitting and fixing the intermediate branching frame part 40 with respect to the recessed groove 60. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle body front structure provided with a pair of left and right front side frames.

  Conventionally, in a vehicle body front structure of an automobile, a pair of left and right front side frames extending in the front-rear direction is provided, and the front side frame receives an impact at the time of a frontal collision and appropriately applies the load to a vehicle rear side member (roof It is known to transmit to a panel etc.).

For example, in the following Patent Document 1 and Patent Document 2, a large frontal collision load is received by the front side frame, and the middle part of the front side frame and the front side frame are distributed so that the collision load can be distributed and transmitted from the front pillar to the roof panel side. A structure has been proposed in which a pillar or the like is connected by a connecting frame extending substantially in the vertical direction, and a frontal collision load acting on the front side frame is distributed and transmitted to the front pillar side via the connecting frame.
JP 2003-182633 A JP 2006-21590 A

  By the way, since the front side frame receives a large collision load of the frontal collision and needs to appropriately transmit this collision load to the vehicle body rear side member, it can be deformed by axial compression as late as possible. It is required to transmit the collision load to the vehicle body rear side member.

  However, because the front side frame itself is curved at the kick-up portion, when a collision load is received, bending deformation or the like occurs at the kick-up portion, and a desired load transmission behavior or deformation behavior cannot be obtained. There is a fear.

  For these problems, a weak bead is provided at the front part of the front side frame, and a reinforcement rain or the like is provided at the rear part of the front side frame. However, since the front side frame itself has only been configured with one closed cross section, a large difference in rigidity cannot be set, and desired load transmission characteristics and the like can be obtained. There was a possibility that it could not be obtained.

  Accordingly, the present invention provides a vehicle body front structure having a pair of left and right front side frames that extend in the longitudinal direction of the vehicle body, and reliably sets a difference in rigidity in the longitudinal direction of the front side frame while maintaining a desired load transmission behavior and deformation behavior. An object of the present invention is to provide a vehicle body front part structure capable of obtaining the above.

  The vehicle body front structure according to the present invention is a vehicle body front structure including a pair of left and right front side frames extending in the vehicle front-rear direction, and a recess extending rearward from the front-rear intermediate portion is formed on a side surface of the front side frame. And the intermediate closed cross-section member extended in the back side from the intermediate part of the front-back direction of a recessed part is connected with respect to this recessed part.

According to the above configuration, the frame cross section of the front side frame is configured with a substantially rectangular closed cross section at the front side frame front portion, and a rectangular closed cross section that is partially recessed due to the recess at the front side frame intermediate portion. In the rear part of the front side frame, a plurality of closed cross sections including a closed cross section of the intermediate closed cross section member are added.
For this reason, since the cross-sectional structure of the frame cross section is configured so that it gradually becomes a complex shape as it goes to the rear side of the front side frame, the rigidity of the front side frame itself is gradually gradually increased toward the rear side of the vehicle body. Can be bigger.

In one embodiment of the present invention, the number of the side walls of the front side frame and the intermediate closed cross-section member is set so as to increase sequentially from the front of the vehicle body.
According to the above configuration, the number of horizontal walls of the front side frame gradually increases, for example, two at the front side frame front part, four at the front side frame middle part, and six at the front side frame rear part. .
For this reason, the rigidity with respect to the vertical behavior change of the front side frame at the time of a frontal collision can be increased, and the risk of bending deformation in the vertical direction can be eliminated.
Therefore, it is possible to prevent the front side frame from being bent and deformed in the vertical direction at the time of a frontal collision, to generate axial compression more reliably, and to obtain a desired load transmission behavior and deformation behavior.

In one embodiment of the present invention, the front side frame is divided into an upper closed cross-section member and a lower closed cross-section member by the recess, and the front pillar extends upward on the outer side of the vehicle width. The lower closed cross-section member is connected to a side sill extending to the rear side of the vehicle body on the lower outer side of the vehicle width, and the intermediate closed cross-section member is connected to a tunnel portion extending to the rear side of the vehicle body on the inner side of the vehicle width. Is.
According to the said structure, a front side frame and an intermediate | middle closed cross-section member are connected with rigid members, such as a front pillar, a side sill, and a tunnel part which are located in three directions radially centering on a front side frame position.
For this reason, the frontal collision load acting on the front side frame is distributed almost uniformly to the rigid members located radially in three directions, and the collision load acting on the front side frame is reliably transmitted to the rear side of the vehicle body. Can be transmitted to the rigid member on the side.
Therefore, since there is no bias in the load transmission of the front side frame, the front side frame is reliably axially compressed, and the collision load can be effectively absorbed by the front side frame.

In one embodiment of the present invention, the intermediate closed cross-section member is installed so as to be substantially fitted in the vehicle width inward side of the concave portion, and an upper flange portion extending above the intermediate closed cross-section member is disposed on the upper closed side. A lower flange portion that is joined to the vehicle width inward side of the cross-sectional member and extends below the intermediate closed cross-sectional member is joined to the vehicle width inward side of the lower closed cross-sectional member.
According to the above configuration, when the front side frame receives a frontal collision load, each closed cross-section member tries to move in the direction opposite to the connection position due to the action / reaction relationship. They will suppress each other.
In other words, the intermediate closed cross-section member connected to the tunnel portion tries to move outward in the vehicle width when receiving a collision load from the front, but the concave portion of the front side frame and the upper and lower flanges of the intermediate closed cross-section member The behavior is suppressed by the lower and upper closed cross-section members with which the parts abut. Further, the upper closed cross-section member connected to the front pillar tries to move inward in the vehicle width when receiving a collision load from the front, but its behavior is suppressed by the upper flange portion of the intermediate closed cross-section member. Furthermore, the lower closed cross-section member connected to the side sill also tries to move inward in the vehicle width when it receives a collision load from the front, but its behavior is suppressed by the lower flange part of the intermediate closed cross-section member. become.
For this reason, since each closed cross-section member restrains the position of each other when receiving a frontal collision load, the collisional load can be reliably transmitted to the front pillar, the tunnel portion, and the side sill.
Therefore, in the front side frame configured to divide the closed cross-section member in three directions and connect to the front pillar, tunnel portion, and side sill, more securely against the three rigid members (front pillar, tunnel portion, side sill) The load can be transmitted.

In one embodiment of the present invention, the upper closed cross-section member is formed by joining a vertical wall plate positioned on the outer side of the vehicle width and a substantially hat-shaped member positioned on the inner side of the vehicle width. The cross-sectional member is formed by joining a vertical wall plate positioned on the inner side of the vehicle width and a substantially hat-shaped member positioned on the outer side of the vehicle width, and the lower closed cross-sectional member is positioned on the outer side of the vehicle width. And the upper side wall of the substantially hat-shaped member of the intermediate closed cross-section member is below the substantially hat-shaped member of the upper closed cross-section member. The lower side wall of the substantially hat-shaped member of the intermediate closed cross-section member is set so as to contact the upper side wall of the substantially hat-shaped member of the lower closed cross-sectional member.
According to the above configuration, each of the closed cross-section members that are intended to move in the direction opposite to the connection position due to the action / reaction relationship by installing the substantially hat-shaped members constituting each closed cross-section member so as to overlap in the vertical direction. Can be suppressed more reliably.
That is, the upper closed cross-section member connected to the front pillar tries to move downward when receiving a collision load from the front, but the behavior is suppressed by the presence of the substantially hat-shaped member of the intermediate closed cross-section member. It is done. In addition, the lower closed cross-section member connected to the side sill also tries to move upward when it receives a collision load from the front, but the presence of the substantially hat-shaped member of the intermediate closed cross-section member makes its behavior It can be suppressed. Further, the substantially hat-shaped member of the intermediate closed cross-section member also tries to move outward in the vehicle width when receiving a collision load from the front, but there are upper and lower flanges of the upper closed cross-section member and the lower closed cross-section member. This suppresses the behavior.
For this reason, the behavior caused by the action and reaction of each closed cross-section member is reliably suppressed not only in the horizontal direction but also in the vertical direction, and the collision load is more reliably distributed to the front pillar, tunnel part, and side sill. can do.
Therefore, in the front side frame configured to be connected to the front pillar, the tunnel portion, and the side sill, the load can be reliably transmitted to the three rigid members (front pillar, tunnel portion, side sill).

In an embodiment of the present invention, the intermediate closed cross-section member is fastened and fixed to the front side frame with a fastening bolt that penetrates the front side frame in the vertical direction.
According to the above configuration, by fixing the intermediate closed cross-section member to the front side frame with the fastening bolt, the collision load acting on the front side frame is reliably transmitted to the intermediate closed cross-section member via the fastening bolt. It will be.
That is, by fixing the intermediate closed cross-section member and the front side frame via another member called a fastening bolt, a collision load acting from the front is applied to the intermediate closed cross-section member fixed from the middle to the front side frame. It can be transmitted reliably.
Therefore, the collision load can be reliably transmitted to the intermediate closed cross-section member, and the load distribution can be reliably performed.

In one embodiment of the present invention, the fastening bolt is a suspension frame mounting bolt.
According to the above configuration, the fastening bolt can also serve as the mounting bolt of the suspension frame.
Further, by using fastening bolts penetrating a plurality of closed cross sections as mounting bolts for the suspension frame, the support rigidity of the suspension frame can be increased.
Therefore, the number of parts can be reduced, and the load input from the suspension frame to the front side frame can be reliably supported, and the steering stability of the vehicle can be improved.

In one embodiment of the present invention, the fastening means for fixing the engine mount is inserted over the upper and lower surfaces above the concave portion of the front side frame.
According to the above configuration, the fastening means for fixing the engine mount can be inserted and fixed using the upper and lower surfaces generated by forming the recesses in the front side frame.
Thereby, a fastening means can be installed in a front side frame, without providing the attachment bracket of the fastening means conventionally required in a front side frame.
Therefore, the mounting structure of the engine mount can be simplified.

According to the present invention, since the cross-sectional structure of the frame cross section is configured so as to gradually become a complex shape as it goes to the rear side of the front side frame, the rigidity of the front side frame itself is surely secured toward the rear side of the vehicle body. Can be gradually increased.
Therefore, in a vehicle body front structure having a pair of left and right front side frames extending in the longitudinal direction of the vehicle body, it is possible to obtain a desired load transmission behavior and deformation behavior while reliably setting a rigidity difference in the longitudinal direction of the front side frame. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the overall structure of the vehicle body front structure according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall perspective view of the front body structure. 2 is a side view of the vicinity of the right front side frame as seen from the inside of the vehicle width, FIG. 3 is a side view of the vicinity of the right front side frame as seen from the outside of the vehicle width, and FIG. 4 is a front view of the vicinity of the right front side frame. FIG. 5 is a plan view near the right front side frame, and FIG. 6 is a bottom view near the right front side frame. The body side panel of FIG. 3 is in a state where the outer panel is removed.

  As shown in FIG. 1, the vehicle body front structure BF includes a pair of left and right front side frames 1, 1 extending in the front-rear direction and a bumper that connects the front end portions of the front side frames 1, 1 extending in the vehicle width direction. A frame 2, suspension towers 3 and 3 erected substantially vertically on the outer side of the intermediate portion of the front side frames 1 and 1, and an apron rain 4 extending in the longitudinal direction of the vehicle body on the outer side of the upper end of the suspension towers 3 and 3. , 4, a dash panel 5 that extends in the vehicle width direction and in the vertical direction behind the front side frames 1, 1 and partitions the engine room ER and the vehicle compartment CB, and a cowl box that extends in the vehicle width direction at the upper end of the dash panel 5 6, a body side panel 7 that is connected to the side end of the cowl box 6 to form a side wall of the cabin, and extends substantially horizontally from the lower end of the dash panel 5 to the rear of the vehicle body. That is provided with a floor panel 8, a.

  A substantially well-shaped suspension frame 9 that supports a front wheel front suspension device (not shown) is installed below the front side frames 1, 1. The side frame 1 and the floor panel 8 are fastened and fixed.

  Further, the body side panel 7 includes a front pillar 11 positioned above the coupling position of the cowl box 6, a door hinge pillar 12 positioned below the coupling position of the cowl box 6 and extending in the vertical direction, and the door hinge pillar 12. Side sill 13 extending from the vehicle body rear side and positioned on the side of the floor panel 8.

  As shown in FIG. 2, the front side frames 1, 1 include a main frame portion 20 that extends in the front-rear direction of the vehicle body at the front portion, and branch frame portions 30, 40, 50 that branch in three directions on the rear side. Yes.

  Among these, the branch frame part is composed of a total of three parts, an upper branch frame part 30, an intermediate branch frame part 40, and a lower branch frame part 50. Each rear end part 31, 41, 51 is connected to a vehicle. The front pillar 11 is located on the outer side of the width, the tunnel part 14 is located on the inner side of the vehicle width, and the side sill 13 is located on the lower side of the outer side of the vehicle.

  Specifically, as shown in FIG. 4, the upper branch frame portion 30 is curved upward outward in the vehicle width and connected to the lower portion 11 a of the front pillar 11, and the intermediate branch frame portion 40 is inward of the vehicle width. The lower branch frame portion 50 is bent downward and outward in the vehicle width and is connected to the front end 13a of the side sill 13 by being bent to the side and connected to the front end upper corner portion 14a of the tunnel portion 14.

  By connecting in this way, as shown in FIG. 4, each branch frame part 30, 40, 50 extends radially at an interval of about 120 ° around the position of the main frame part 20 in front view, The collision load acting from the front of the vehicle body can be transmitted to each of the rigid members (11, 13, 14) on the rear side of the vehicle body substantially evenly.

  As shown in FIG. 5, the branch point X of each of the branch frame portions 30, 40, 50 is set at a position spaced a predetermined amount forward from the dash panel 5. A predetermined deformation space S is formed between the two.

  That is, the branch frame portions 30, 40, and 50 are branched just like a “camera tripod”, so that a deformation space S is formed with the dash panel 5, and this branch is generated at the time of a frontal collision. The point X is retracted backward in the vehicle body so that the collision load is absorbed by each of the branch frame portions 30, 40, 50.

  Also, as shown in FIGS. 2, 3, 5, and 6, the shape of each branch frame portion 30, 40, 50 is formed so as to be bent in the respective connecting directions after once extending backward. Therefore, bending deformation is likely to occur at this curved position. Further, as shown in FIG. 4, since the flat plate portions 32, 42, 52 constituting the closed cross section of each branch frame portion 30, 40, 50 are set on the inner side of the bending position, the bending position is further increased. Thus, the branch frame portions 30, 40, 50 are easily bent and deformed.

  The upper branch frame portion 30 is configured with a round pipe 33 at the rear, so that deformation at this portion is suppressed as much as possible, and a collision load from the front of the vehicle body can be reliably transmitted to the front pillar 11. is doing.

  Next, the structure of the front side frame 1, which is a characteristic part of the present embodiment, will be described in more detail with reference to FIGS. 7 is a detailed perspective view of the front side frame, FIG. 8 is a cross-sectional view taken along line AA, FIG. 9 is a cross-sectional view taken along line BB, and FIG. 10 is a cross-sectional view taken along line CC.

As described above, the front side frame 1 includes the main frame portion 20 and the three branch frame portions 30, 40, and 50, each of which forms a closed cross section.
As shown in FIG. 8, the main frame portion 20 is formed by joining a vertical wall plate 21 located on the outer side of the vehicle width and a substantially hat-shaped main member 22 to form a first oblong rectangular first closed cross section W1. Is configured.

  Further, as shown in FIG. 9, the upper branch frame portion 30 and the lower branch frame portion 50 have a substantially hat-shaped first sub member 33 and a second sub member with respect to the same vertical wall plate 21 as the first closed cross section W1. By joining the members 53 in the vertical position, a substantially rectangular second closed cross section W2 and third closed cross section W3 are formed.

  Further, as shown in FIG. 10, the intermediate branch frame portion 40 joins a vertical wall plate 44 located on the vehicle width inward side and a substantially hat-shaped third submember 43 to thereby form a fourth closed cross section W4. Is configured.

The closed cross sections (W1, W2, W3, W4) of the front side frames 1 are configured to increase sequentially from the front of the vehicle body to the rear side.
As shown in FIG. 7, the increase in the closed cross section (W1, W2, W3, W4) forms a concave groove 60 extending rearward from the middle position in the front-rear direction on the inner side surface of the front side frame 1, This is achieved by further fitting and fixing the intermediate branch frame portion 40 to the concave groove 60.

  By increasing the closed cross section (W1, W2, W3, W4) in the front side frame 1 in this way, the rigidity of the front side frame 1 can be sequentially increased in the order of the front portion, the middle portion, and the rear portion. That is, by sequentially increasing the closed cross section (W1, W2, W3, W4), even if the frame area is the same, the vertical wall and the horizontal wall are increased, and the frame rigidity can be increased.

  In addition, since the closed cross section sequentially increases, a large difference in rigidity does not occur at a stretch, and therefore, the occurrence of stress concentration in a portion where the difference in rigidity occurs can be reduced.

  The concave groove 60 is formed so as to be gradually recessed inward of the front side frame 1 from the rear position of the joint portion 20a of the main member portion 20. For this reason, there is no abrupt cross-sectional change while the closed cross section changes from the first closed cross-section W1 to the second closed cross-section W2 and the third closed cross-section W3. Yes.

As will be described later, the intermediate branch frame portion 40 is joined to the upper branch frame portion 30, the lower branch frame portion 50, and the like. In order to increase the coupling strength therebetween, a suspension frame mounting bolt 61 for attaching the suspension frame 9 is used. Even the fastening is fastened.
Specifically, as shown in FIG. 9, the suspension frame mounting bolt 61 is connected to the through holes 36 and 36 of the upper horizontal wall 34 and the lower horizontal wall 35 of the upper branch frame portion 30, and the upper horizontal wall 45 and lower of the intermediate branch frame portion 40. The intermediate branch frame is inserted into the through holes 47, 47 of the horizontal wall 46 and the through holes 56, 56 of the upper horizontal wall 54 and the lower horizontal wall 55 of the lower branch frame part 50, and the fastening nut 62 is screwed and fixed. The portion 40 is fastened and fixed between the upper branch frame portion 30 and the intermediate branch frame portion 40.

  As described above, the intermediate branch frame portion 40 is fastened and fixed by the suspension frame mounting bolt 61, so that the intermediate branch frame portion 40 fixed from the middle of the front side frame 1 is also interposed via the suspension frame mounting bolt 61. The collision load can be transmitted reliably.

  Further, the suspension frame mounting bolt 61 side is also fastened and fixed to the front side frame 1 at this portion, so that even when a suspension load is received from the suspension frame 9 side, each branch frame portion 30, 40, 50 has Since the load can be distributed and transmitted, the suspension support rigidity can be increased.

  Further, as shown in FIG. 7, the upper branch frame 30 positioned above the concave groove 60 is provided with two engine mount mounting high nuts (long nuts) 63 and 63 so as to penetrate in the vertical direction. ing.

  Specifically, as shown in FIG. 10, an engine mount mounting high nut 63 is inserted into the through holes 37 formed in the upper horizontal wall 34 (upper surface) and the lower horizontal wall 35 (lower surface) of the upper branch frame portion 30. And the engine mount attachment part EM which attaches an engine mount apparatus (not shown) is comprised by joining to the upper branch frame part 30 by arc welding w etc. The engine mount device is assembled from above the engine mount mounting high nut 63.

  In this manner, by providing the engine mount mounting high nut 63 in the upper branch frame portion 30, the engine mount mounting portion EM can be configured in the front side frame 1 without setting a separate mounting bracket or the like.

  Next, a method of joining the front side frames 1 will be described with reference to FIGS. 11A is a schematic sectional view showing the first stage of the joining process, FIG. 11B is a schematic sectional view showing the second stage, and FIG. 12C is a schematic sectional view showing the third stage. (D) is the schematic cross section which showed the 4th step.

  First, in the first stage shown in (a), the first sub member 33 and the second sub member 53 are joined. At this stage, the lower flange 38 of the first sub member 33 and the upper flange 57 of the second sub member 53 are overlapped and welded by spot welding (the x mark is a welding point). After this spot welding, the third sub member 43 is assembled from the vehicle width inward side position.

  Next, in the second stage shown in (b), the third sub member 43 is joined to the first sub member 33 and the second sub member 53. At this stage, the upper flange 48 of the third sub member 43 is spot welded to the inner vertical wall 33 a of the first sub member 33, and the lower flange 49 is spot welded to the inner vertical wall 53 a of the second sub member 53. At this time, the third sub member 43 is joined and fixed so that a substantially hat cross section is fitted between the first sub member 33 and the second sub member 53. After this spot welding, the vertical wall plate 21 is assembled from the position outside the vehicle width.

  Further, in the third stage shown in (c), the vertical wall plate 21 is joined to the frame assembly U1 such as the first submember 33. At this stage, the upper end portion 21 a of the vertical wall plate 21 is spot welded to the upper flange 39 of the first sub member 33, and the intermediate portion 21 b of the vertical wall plate 21 is connected to the outer vertical wall 43 a of the third sub member 43, The bottom flange 38 of the first sub-frame 33 and the upper flange 57 of the second sub-frame 53 are spot-welded in four layers, and the lower end portion 21c of the vertical wall plate 21 is further connected to the lower flange of the second sub-member 53. Spot weld to 58. Thereby, the 2nd closed section W2 and the 3rd closed section W3 of upper branch frame part 30 and lower branch frame part 50 are constituted. After the spot welding, the vertical wall plate 44 of the intermediate branch frame portion 40 is assembled from the vehicle width inward side position.

  Finally, in the fourth stage shown in (d), the vertical wall plate 44 of the intermediate branch frame portion 40 is joined to the frame assembly U2 such as the first submember 33. At this stage, the upper end 44a of the vertical wall plate 44 is spot-joined to the upper flange 48 of the third subframe 43 and the inner vertical wall 33a of the first subframe 33, and the lower end 44b of the vertical wall plate 44 is connected to the third subframe 43. Spot joining is performed on the lower flange 49 of the sub frame 43 and the inner vertical wall 53 a of the second sub frame 53. Thereby, the fourth closed cross section W4 of the intermediate branch frame portion 40 is configured, and each of the branch frame portions 30, 40, 50 can be configured as an integral frame assembly. In order to perform this spot operation, it is desirable to form a welding operation hole OP as shown in the vertical wall plate 21 on the outer side of the vehicle width.

  By joining the three branch frame parts 30, 40, 50 by the joining method as described above, the branch frame parts 30, 40, 50 are integrated, and the rigid members (11, The collision load can be reliably transmitted to 13,14).

  In particular, the structure of each of the branch frame portions 30, 40, 50 is configured by combining the substantially hat-shaped submembers (33, 43, 53) and the vertical wall plates 21, 44. Is higher. That is, by such a combined structure, the behavior of the branch frame portions 30, 40, 50 caused by the action / reaction relation generated at the time of a collision can be canceled each other, and the rigid member (11, 13) , 14) can reliably transmit the collision load.

  The cancellation of the behavior of each of the branch frame portions 30, 40, 50 caused by this action / reaction relationship will be described with reference to FIG.

  As described above, in each of the branch frame portions 30, 40, 50, the upper branch frame portion 30 is connected to the front pillar 11 at the vehicle width outer side upper position, and the intermediate branch frame portion 40 is a tunnel in the vehicle width inner position. The lower branch frame portion 50 is connected to the side sill 13 at the lower position on the outer side of the vehicle width.

  For this reason, when a collision load acts from the front portion of the front side frame 1, the front ends of the branch frame portions 30, 40, and 50, which are the branch points X (see FIG. 5) of the front side frame 1, due to the action / reaction relationship. The part has a behavior (indicated by an arrow) that attempts to move in the direction opposite to the connection position.

With respect to the behavior that moves in the opposite direction, the behavior is regulated by the presence of the branch frame portions 30, 40, and 50.
First, the upper branch frame portion 30 tends to move downward in the vehicle width inward direction (arrow α), which is the direction opposite to the front pillar 11. On the other hand, the upper flange 40A of the intermediate branch frame portion 40 restricts the inward movement of the vehicle width, and the upper horizontal wall 40B (fourth closed cross section W4) of the intermediate branch frame portion 40 extends downward. The movement will be regulated.

  Further, the intermediate branch frame portion 40 tends to move to the vehicle width outward side (arrow β) which is the opposite direction to the tunnel portion 14. On the other hand, the movement toward the vehicle width outward side is restricted by the presence of the lower flange 30C of the upper branch frame portion 30, the upper flange 50A of the lower branch frame portion 50, and the vertical wall plate 21. become.

  Further, the lower branch frame portion 50 tends to move upward inward in the vehicle width (arrow γ), which is the direction opposite to the side sill 13. On the other hand, the lower flange 40C of the intermediate branch frame portion 40 restricts the inward movement of the vehicle width, and the lower lateral wall 40D (fourth closed cross section W4) of the intermediate branch frame portion 40 moves upward. Will be regulated.

  Therefore, even if a large collision load is applied from the front side of the front side frame 1 in the case of a frontal collision, the branch frame portions 30, 40, 50 are not separated at the branch point X (see FIG. 5). The collision load can be reliably transmitted to the rigid members (11, 13, 14) on the rear side of the vehicle body.

  As described above, it is possible to obtain the effect of the front side frame 1 that branches and extends more reliably in three directions.

Next, the effect of this embodiment is demonstrated.
In this embodiment, a concave groove 60 extending rearward from the front-rear direction intermediate portion is formed on the side surface of the front side frame 1, and an intermediate branch extending rearward from the front-rear direction intermediate portion of the concave groove 60 with respect to the concave groove 60. The frame part 40 is connected.

Thereby, the frame cross section of the front side frame 1 is constituted by a substantially rectangular first closed cross section W1 at the front part of the front side frame 1, and the front side frame 1 is divided into upper and lower parts by the concave groove 60 at the middle part of the front side frame 1 It is composed of two closed cross sections W2 and a third closed cross section W3, and at the rear part of the front side frame 1, it is composed of three closed cross sections (W2, W3, W4) including the fourth closed cross section W4 of the intermediate branch frame 40. Will be.
For this reason, since the cross-sectional structure of the front side frame 1 is configured so as to gradually become a complex shape toward the rear side of the front side frame 1, the rigidity of the front side frame 1 itself is increased toward the rear side of the vehicle body. It can surely be gradually increased.
Therefore, in a vehicle body front structure including a pair of left and right front side frames 1 and 1 extending in the longitudinal direction of the vehicle body, a desired load transmission behavior and deformation behavior can be set while reliably setting a rigidity difference in the longitudinal direction of the front side frame 1. Can be obtained.

In this embodiment, the number of horizontal walls of the front side frame 1 is set so as to increase sequentially from the front of the vehicle body.
Specifically, two (22a, 22b) (see FIG. 8) are provided at the front part of the front side frame 1, and four (34, 35, 53b, 53c) (see FIG. 9) are provided at the middle part of the front side frame 1. The rear part of the side frame 1 is set to have six (34, 35, 45, 46, 54, 55) (see FIG. 10).

Thereby, the rigidity with respect to the vertical behavior change of the front side frame 1 at the time of a frontal collision can be increased, and the possibility of bending deformation in the vertical direction can be eliminated.
Therefore, it is possible to prevent the front side frame 1 from being bent and deformed in the vertical direction at the time of a frontal collision, to generate axial compression more reliably, and to obtain a desired load transmission behavior and deformation behavior.

Further, in this embodiment, the upper branch frame portion 30 is connected to the front pillar 11 extending upward on the outer side of the vehicle width, and the side sill extending lower side of the vehicle width on the rear side of the vehicle body. 13 and the intermediate branch frame portion 40 is connected to the tunnel portion 14 extending inward of the vehicle body on the vehicle width inward side.
Thereby, each branch frame part 30,40,50 of the front side frame 1 is made into rigid members, such as the front pillar 11, the side sill 13, and the tunnel part 14, which are located in three directions radially around the position of the main frame part in a front view. Will be linked.
For this reason, the frontal collision load that acts on the front side frame 1 is distributed and transmitted substantially uniformly to the rigid members (11, 13, 14) that are radially disposed in three directions. The collision load to be transmitted can be reliably transmitted to the rigid members (11, 13, 14) on the rear side of the vehicle body.
Therefore, since there is no bias in the load transmission of the front side frame 1, the front side frame 1 is surely axially compressed, and the front side frame 1 can effectively absorb the collision load.

Further, in this embodiment, the intermediate branch frame portion 40 is installed so as to be substantially fitted to the vehicle width inner side of the concave groove 60, and the upper flange 40 </ b> A of the intermediate branch frame portion 40 is attached to the upper branch frame portion 30. The lower flange 40C of the intermediate branch frame portion 40 is joined to the vehicle width inner side (53a) of the lower branch frame portion 50 (see FIG. 13).
As a result, when the front side frame 1 receives a frontal collision load, the behavior of each branch frame portion 30, 40, 50 trying to move in the direction opposite to the connection position due to the action / reaction relationship is shown in each branch frame portion. It is possible to suppress each other between 30, 40 and 50.
In particular, by installing the substantially hat-shaped members (33, 43, 53) constituting the respective branch frame portions 30, 40, 50 so as to overlap each other in the vertical direction, the connection position is opposite to the connection position due to the action and reaction. The behavior of each branch frame part 30, 40, 50 to be moved can be more reliably suppressed.
For this reason, since each branch frame part 30,40,50 restrains the position mutually when receiving a frontal collision load, the collision load is reliably distributed to the front pillar 11, the tunnel part 14, and the side sill 13. Can communicate.
Therefore, in the front side frame 1 configured such that each branch frame portion 30, 40, 50 is branched in three directions and connected to the front pillar 11, the tunnel portion 14, and the side sill 13, the three rigid members (front A load can be transmitted to the pillar 11, the tunnel portion 14, and the side sill 13).

Further, in this embodiment, the intermediate branch frame portion 40 is fastened and fixed by a suspension frame mounting bolt 61 that passes through the front side frame 1 in the vertical direction (see FIG. 10).
Thereby, the collision load acting on the front side frame 1 is reliably transmitted to the intermediate branch frame portion 40 via the suspension frame mounting bolt 61.
That is, by fixing the intermediate branch frame portion 40 through another member called the suspension frame mounting bolt 61, the collision that acts from the front against the intermediate branch frame portion 40 fixed to the front side frame 1 from the middle. The load can be transmitted reliably.
Therefore, the collision load can be reliably transmitted to the intermediate branch frame portion 40, and the load distribution can be reliably performed.
Note that a separate fastening bolt may be set for the suspension frame mounting bolt 61 to fasten and fix the intermediate branch frame portion 40.

In particular, in this embodiment, since the intermediate branch frame portion 40 is fastened and fixed by the suspension frame mounting bolt 61, the fastening bolt for fastening the intermediate branch frame portion 40 and the bolt for attaching the suspension frame 9 can be used. .
Further, since the suspension frame mounting bolt 61 passes through the branch frame portions 30, 40, 50, the fastening strength of the suspension frame mounting bolt 61 is increased, and the support rigidity of the suspension frame 9 can be increased.
Therefore, the number of parts can be reduced, and the load input from the suspension frame 9 to the front side frame 1 can be reliably supported, and the steering stability of the vehicle can be improved.

In this embodiment, the engine mount mounting high nut 63 is inserted across the upper surface (upper horizontal wall 34) and the lower surface (lower horizontal wall 35) of the upper branch frame portion 30 (see FIG. 9).
Thus, the engine mount mounting high nut 63 can be inserted and fixed using the upper and lower surfaces of the upper branch frame portion 30.
For this reason, the engine mount mounting portion EM can be configured without providing a mounting bracket for the engine mount mounting high nut 63 that is conventionally required separately in the front side frame 1.
Therefore, the engine mount mounting part EM can be simplified.
In this embodiment, the high nut for mounting the engine mount is installed in the upper branch frame portion 30. In addition, a fastening bolt or the like for fixing the engine mount is inserted into the upper branch frame portion 30. It may be configured.

  In the present embodiment, each plate thickness of the front side frame 1 has been described without any particular limitation. However, the main frame portion 20 is formed of a thin plate thickness member, and each branch frame portion 30, 40, 50 is thick. By configuring with a plate-thickness member, the main frame portion 20 may be more axially compressed, and the branch frame portions 30, 40, 50 may be made more difficult to deform.

  Further, in each of the branch frame portions 30, 40, 50, the plate thickness is varied, the upper branch frame portion 30 is thickest, the intermediate branch frame portion 40 is next thickened, and the lower branch frame portion 50 is the highest. By thinning, bending of the front side frame 1 when the vehicle body is nose dive may be suppressed as much as possible.

  Further, the main frame part 20, the upper branch frame part 30, and the lower branch frame part 50 other than the intermediate branch frame member 40 may be configured as an integral frame member.

As described above, in the correspondence between the configuration of the present invention and the above-described embodiment,
The concave portion of the present invention corresponds to the concave groove 60 of the embodiment,
Hereinafter, similarly, the intermediate closed cross-section member corresponds to the intermediate branch frame portion 40,
The upper closed cross-section member corresponds to the upper branch frame portion 30,
The lower closed cross-section member corresponds to the lower branch frame portion 50,
The fastening bolt and mounting bolt correspond to the suspension frame mounting bolt 61,
The present invention is not limited to the above-described embodiment, but includes all vehicle body front structure embodiments.

The whole vehicle body front part structure perspective view concerning an embodiment. The side view which looked at the right front side frame vicinity from the vehicle width inner side. The side view which looked at the right front side frame vicinity from the vehicle width outer side. The front view of the right front side frame vicinity. The top view of the right front side frame vicinity. The bottom view of the right front side frame vicinity. The detailed perspective view of a front side frame. FIG. 8 is a cross-sectional view taken along line AA in FIG. 7. FIG. 8 is a cross-sectional view taken along line B-B in FIG. 7. CC sectional view taken on the line of FIG. (A) The schematic cross section which showed the 1st step of the joining process, (b) The schematic cross section which showed the 2nd step. (C) The schematic cross section which showed the 3rd step, (d) The schematic cross section which showed the 4th step. Sectional drawing explaining cancellation of the behavior by the relationship between action and reaction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front side frame 5 ... Dash panel 11 ... Front pillar 13 ... Side sill 14 ... Tunnel part 30 ... Upper branch frame part 40 ... Middle branch frame part 50 ... Lower branch frame part 61 ... Suspension frame mounting bolt

Claims (8)

A vehicle body front structure having a pair of left and right front side frames extending in the longitudinal direction of the vehicle body,
Forming a recess extending rearward from the front-rear direction intermediate portion on the side surface of the front side frame;
A vehicle body front structure in which an intermediate closed cross-section member extending rearward from the front-rear direction intermediate portion of the recess is connected to the recess. The vehicle body front part structure according to claim 1, wherein the number of lateral walls of the front side frame and the intermediate closed cross-section member is set so as to increase sequentially from the front of the vehicle body. The front side frame is divided into an upper closed cross-section member and a lower closed cross-section member by the recess,
Connecting the upper closed cross-section member to a front pillar extending upward on the vehicle width outer side;
The lower closed cross-section member is connected to a side sill extending on the vehicle body rear side below the vehicle width outward side,
The vehicle body front part structure according to claim 1 or 2, wherein the intermediate closed cross-section member is connected to a tunnel portion extending toward the vehicle rear side on the vehicle width inward side. The intermediate closed cross-section member is installed so as to be approximately fitted to the vehicle width inward side of the recess,
An upper flange portion extending upward of the intermediate closed cross-section member is joined to the vehicle width inward side of the upper closed cross-section member,
The vehicle body front structure according to claim 3, wherein a lower flange portion extending downward from the intermediate closed cross-section member is joined to a vehicle width inward side of the lower closed cross-section member. The upper closed cross-section member is configured by joining a vertical wall plate located on the vehicle width outer side and a substantially hat-shaped member located on the vehicle width inner side,
The intermediate closed cross-section member is configured by joining a vertical wall plate located on the vehicle width inner side and a substantially hat-shaped member located on the vehicle width outer side,
The lower closed cross-section member is configured by joining a vertical wall plate positioned on the vehicle width outer side and a substantially hat-shaped member positioned on the vehicle width inner side,
The upper side wall of the substantially hat-shaped member of the intermediate closed cross-section member is set so as to contact the lower side wall of the substantially hat-shaped member of the upper closed cross-section member, and the lower side wall of the substantially hat-shaped member of the intermediate closed cross-section member is The vehicle body front part structure according to claim 4, which is set so as to abut on an upper lateral wall of a substantially hat-shaped member of the side closed section member. The vehicle body front part structure according to any one of claims 1 to 5, wherein the intermediate closed cross-section member is fastened and fixed to the front side frame by fastening bolts that penetrate the front side frame in the vertical direction. The vehicle body front part structure according to claim 6, wherein the fastening bolt is a mounting bolt for a suspension frame. The vehicle body front part structure according to any one of claims 1 to 7, wherein fastening means for fixing the engine mount is inserted across the upper and lower surfaces above the concave portion of the front side frame.

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