Vehicle body front structure

Abstract

To provide a vehicle body front structure which can obtain smooth collapse of a front side frame when an impact load from the front is input, while fixing a rear region of the front side frame to a load transmission block by a fastening member.SOLUTION: A vehicle body front structure includes a front side frame 10, and a load transmission block 11 which is a cast component. The load transmission block has a frame insertion part 30 and a load support wall 32. The front side frame is provided with a bracket 33 which projects in a direction crossing a longitudinal direction and is abutted on the front face of the load support wall. The front side frame is fixed to the peripheral wall of the frame insertion part from a vertical direction by a first fastening member, and is fixed to the peripheral wall from a vehicle width direction by a second fastening member, in a state of being inserted into the frame insertion part of the load transmission block. The bracket is fixed to the load support wall of the load transmission block from the longitudinal direction by a third fastening member.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a vehicle front body structure. [Background technology]

[0002] In recent years, various efforts to provide access to sustainable transportation systems have been gaining momentum. To achieve this, we are focusing on further improving transportation safety and convenience through research into improving vehicle body rigidity.

[0003] A known vehicle body front structure has a pair of front side frames arranged on the left and right sides of the front of the vehicle, with the rear of the front side frames connected to another skeletal member via a load transfer block (see, for example, Patent Document 1).

[0004] The vehicle front body structure described in Patent Document 1 comprises an upper block in which a load transfer block also serves as a strut housing, and a lower block connected to the lower end of the upper block, and a fitting hole extending in the front-rear direction is formed between the upper block and the lower block. The upper block and the lower block are integrally formed by casting. A rear region of a front side frame is fitted into the fitting hole formed by the upper block and the lower block.

[0005] In this vehicle front body structure, a plate-like portion that abuts against a side surface of the rear region of the front side frame is provided in a portion that constitutes a part of the fitting hole on the upper block side, and the plate-like portion is fixed to the side surface of the front side frame by welding. The lower block is connected to the front side frame after the rear region of the front side frame is fixed to the upper block by welding. At this time, the rear region of the front side frame is positioned in a fitted state inside the fitting hole formed between the upper block and the lower block.

[0006] In this front body structure, the load transfer block is composed of an upper block and a lower block, which are cast parts, so that the number of components of the load transfer block can be reduced. Also, the side surface of the rear region of the front side frame is welded to the plate-shaped portion of the upper block, so that the area of ​​the welded portion is wide, and the support rigidity of the rear region of the front side frame can be increased. Therefore, when an impact load is input from the front of the vehicle, the front side frame can be smoothly crushed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2002-166853 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the vehicle front body structure described in Patent Document 1, the load transfer block is composed of an upper block and a lower block, and a plate-shaped portion must be formed on the upper block to weld and fix the front side frame. This makes the structure of the load transfer block complicated, and the work of fixing the front side frame is also cumbersome. Furthermore, when the load transfer block is formed from a cast part, it may be difficult to achieve strong welding depending on the shape of the contact part with the front side frame and the properties of the material of the cast part.

[0009] For this reason, we are currently considering simplifying the structure of the load transfer block and fixing the rear region of the front side frame to the load transfer block with fastening members.

[0010] However, if the rear region of the front side frame is fixed at multiple discrete points with fastening members, it becomes easier for uneven stress to act on a portion of the periphery of the front side frame when an impact load is applied from the front of the vehicle. If uneven stress acts on a portion of the periphery of the front side frame, the stress can cause the front side frame to tilt or bend, preventing the front side frame from collapsing smoothly (absorbing energy).

[0011] Therefore, the present invention aims to provide a vehicle body front structure that can secure the rear region of the front side frame to the load transmission block with a fastening member while smoothly crushing the front side frame when an impact load is input from the front. The present invention will contribute to the development of a sustainable transportation system. [Means for solving the problem]

[0012] In order to solve the above problems, the vehicle body front structure according to the present invention employs the following configuration. A vehicle front body structure according to one aspect of the present invention includes a front side frame (e.g., front side frame 10 in the embodiment) extending substantially along the fore-aft direction at a front side of a vehicle, and a load transfer block (e.g., load transfer block 11 in the embodiment) which is a cast part that connects a rear part of the front side frame to another skeleton member, the load transfer block having a frame insertion part (e.g., frame insertion part 30 in the embodiment) that opens on the front side and into which a rear region of the front side frame is inserted from the opening, and a load support wall (e.g., load support wall 32 in the embodiment) that stands from an edge of the opening in a direction substantially perpendicular to the fore-aft direction, and the load transfer block inserted into the frame insertion part of the front side frame A bracket (e.g., bracket 33 in the embodiment) is provided at a position forward of the portion where the front side frame is inserted into the frame insertion portion of the load transmission block, and the front side frame is fastened and fixed to the peripheral wall of the frame insertion portion from the top-bottom direction by a first fastening member (e.g., bolt 35A in the embodiment) and to the peripheral wall from the vehicle width direction by a second fastening member (e.g., bolt 35B in the embodiment), with the rear region of the front side frame inserted into the frame insertion portion of the load transmission block, and the bracket is fastened and fixed to the load support wall of the load transmission block from the front-to-back direction by a third fastening member (e.g., bolt 34 in the embodiment).

[0013] In the case of the vehicle body front structure configured as above, when an impact load is input from the front of the front side frame, the load is supported by the peripheral wall of the frame insertion part of the load transfer block through the first fastening member and the second fastening member. At this time, the input load is supported in a distributed manner by the wall facing the up-down direction of the frame insertion part and the wall facing the vehicle width direction by the first fastening member and the second fastening member. In addition, the impact load input to the front side frame is also supported by the load support wall of the load transfer block through the third fastening member that fastens and fixes the bracket to the load support wall of the load transfer block. As a result, the input load is also supported in a distributed manner by the load support wall facing the front-rear direction of the load transfer block. Therefore, when an impact load is input from the front, it is difficult for a biased stress to act on a part of the peripheral area of ​​the front side frame, and the front side frame is less likely to tilt or bend.

[0014] The load support wall of the load transfer block may rise upward from an edge of the opening, and the bracket may rise upward from an upper surface of the front side frame.

[0015] In this case, when the bracket is fastened to the load support wall of the load transfer block by the third fastening member, the rear region of the front side frame is fixed to the load transfer block in a manner that it is suspended from above via the bracket. Therefore, the rear region of the front side frame is stably supported by the load transfer block. In addition, when an impact load is input from the front, the rear region of the front side frame is less likely to tilt or bend.

[0016] The load transmission block may further have an enclosing wall (e.g., enclosing wall 50 in the embodiment) that protrudes forward from around the opening of the frame insertion portion and surrounds the outer peripheral surface of the front side frame, and a crushing receiving space (e.g., crushing receiving space 55 in the embodiment) that receives the crushing portion when the front side frame is crushed in the fore-and-aft direction may be provided between the enclosing wall and the front side frame.

[0017] In this case, when the front side frame is crushed from the front side toward the rear end side due to the input of a front impact load, as the crushing progresses, the crushed portion is received in the crush receiving space between the surrounding wall and the front side frame. Therefore, the rear region of the front side frame is less likely to bend and deform when an impact load is input. Therefore, when this configuration is adopted, it is possible to crush and deform the front side frame more smoothly. In addition, a portion of the crushable portion received in the crushable receiving space is guided around to the front side of the load support wall. As a result, the rear region of the front side frame is restricted from being rearwardly displaced by the contact between the crushable portion and the load support wall. Therefore, the front side frame can be more smoothly crushed and deformed when an impact load is input.

[0018] At least one of the first fastening members and the second fastening members may be provided in plurality and may be arranged in a staggered manner in a direction intersecting the front-rear direction in the front-rear direction.

[0019] In this case, when a front impact load is applied, the crushing of the front side frame progresses to the rear region, and the deformation of the peripheral areas of each fastening member also progresses from the front to the rear. In this case, since the fastening members are arranged in a staggered pattern in this configuration, the deformation points of the rear region of the front side frame are distributed to multiple positions in the vehicle width direction and the vertical direction. Therefore, when this configuration is adopted, it is possible to effectively suppress the collapse and breakage of the front side frame in the later stage of the input of the impact load.

[0020] A reinforcing wall (e.g., reinforcing wall 37 in the embodiment) extending across the internal space of the front side frame is connected to the left and right side walls of the front side frame, and the reinforcing wall may extend so as to straddle at least the fastening portion of the second fastening member in the fore-and-aft direction.

[0021] In this case, the reinforcing walls function to make the load transmitted to the left and right side walls of the front side frame approximately equal when a front impact load is applied, and therefore, when this configuration is adopted, it is possible to effectively prevent the front side frame from collapsing or breaking in the left and right direction in the later stages of the application of the impact load.

[0022] It is preferable that the first fastening member and the second fastening member fasten and fix the front side frame and the frame insertion portion at positions offset from each other in the front-rear direction.

[0023] In this case, when a front impact load is input, as the crushing of the front side frame progresses to the rear region, the peripheral areas of each fastening member also undergo deformation from the front to the rear. In this configuration, the first fastening member and the second fastening member are arranged offset from each other in the front-to-rear direction, so that the peripheral areas of the first fastening member and the second fastening member tend to deform alternately. Therefore, when this configuration is adopted, it is possible to effectively suppress collapse or breakage of the front side frame in the later stage of input of the impact load. Effect of the Invention

[0024] The vehicle front body structure according to the present invention can distribute and support an input impact load in mutually intersecting directions on the peripheral wall of the frame insertion portion of the load transfer block by the first fastening member and the second fastening member, and can further support the load in the front-rear direction on the load support wall of the load transfer block by the third fastening member. Therefore, when an impact load is input from the front, uneven stress is unlikely to act on a part of the peripheral area of ​​the front side frame, and the front side frame is unlikely to tilt or bend. Therefore, when the vehicle front body structure according to the present invention is adopted, it is possible to obtain smooth crushing of the front side frame when an impact load is input from the front, while still fixing the rear area of ​​the front side frame to the load transfer block by the fastening members. [Brief description of the drawings]

[0025] [Figure 1]FIG. 2 is a perspective view of the front part of the vehicle according to the embodiment. [Diagram 2] FIG. 2 is a side view of the front part of the vehicle according to the embodiment. [Diagram 3] FIG. 2 is a perspective view of the load transmission block according to the embodiment, seen from the rear upper side. [Figure 4] 4 is a cross-sectional view of the front part of the vehicle corresponding to the cross section IV-IV in FIG. 3 . [Diagram 5] FIG. 4 is a perspective view showing a fixing portion between the front side frame and the load transmission block according to the embodiment. [Figure 6] FIG. 5 is an enlarged cross-sectional view of a portion of FIG. 4. [Figure 7] 7 is a front view of a fixing portion of the load transmission block and the front side frame of the embodiment, the front side frame being cross-sectionally taken along line VII-VII in FIG. 4. [Figure 8] 8 is a plan view of the front side frame of the embodiment, taken along line VIII-VIII in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, in the appropriate places of the drawings, an arrow FR pointing forward of the vehicle, an arrow UP pointing upward of the vehicle, and an arrow LH pointing to the left side of the vehicle (left side when facing forward) are indicated.

[0027] FIG. 1 is a perspective view of the front part of a vehicle 1 according to this embodiment, and FIG. 2 is a side view of the front part of the vehicle 1 as viewed from the left side. 1 and 2, reference numeral 2 denotes a passenger compartment in which passengers ride, and reference numeral 3 denotes a front compartment in front of the passenger compartment 2, in which a drive motor, engine, etc. are housed. Front side frames 10 extending substantially along the front-rear direction of the vehicle body are disposed on both sides of the front compartment 3 in the vehicle width direction. The rear ends of the left and right front side frames 10 are connected to a framework member at the front of the passenger compartment 2 via load transmission blocks 11, which will be described in detail later.

[0028] Side sills 4 extending substantially along the front-rear direction of the vehicle body are disposed on the left and right side portions of the lower portion of the vehicle interior 2. A floor panel 5 disposed below the vehicle interior 2 is mounted on the left and right side sills 4. The floor panel 5 is reinforced by a plurality of reinforcing frames (not shown) extending in the front-rear and width directions of the vehicle body. In this embodiment, the floor panel 5 and these reinforcing frames are collectively referred to as a floor member 12. The left and right front side frames 10 extend forward from a position above the floor member 12.

[0029] The front part of the passenger compartment 2 is separated from the front compartment 3 by a dashboard lower panel 13. The lower end of the dashboard lower panel 13 is connected to the front edge of the floor member 12, and stands upright at an angle forward and upward from the front part of the floor member 12. The upper part of the dashboard lower panel 13 is connected to a cowl top panel 14 and other frame members.

[0030] A front pillar 6 constituting the front edge of the front door opening is connected to the front end of the left and right side sills 4. An upper member 7 extending substantially along the front-rear direction of the vehicle body is connected to the front side of the upper part of each front pillar 6 at a position outside the vehicle width direction of the front compartment 3. The upper member 7 curves downward from the left and right front pillars 6 to the front of the vehicle body, and its front end extends to a position outside the front end of the front side frame 10. The front end of each upper member 7 is connected to the front end of the corresponding left and right front side frame 10 via a connecting member (not shown). Damper housing portions 15 at the left and right upper portions of a load transmission block 11, which will be described in detail later, are connected to base portions (rear regions) of the left and right upper members 7. The damper housing portions 15 support the upper portions of dampers of front suspensions (not shown).

[0031] Fig. 3 is a perspective view of the load transmission block 11 as viewed from above the rear, and Fig. 4 is a cross-sectional view of the front part of the vehicle corresponding to the cross section IV-IV in Fig. 3. Each of the left and right front side frames 10 fixed to the load transmission block 11 is formed into a rectangular (square) frame shape as shown in Figures 1 and 4. The rear end of the front side frame 10 is inserted into a frame fixing portion 17 of the load transmission block 11, which will be described later, and in this state is fixed to the frame fixing portion 17 by a plurality of bolts 35A, 35B (fastening members). The front side frame 10 is formed from, for example, aluminum or an iron-based metal.

[0032] FIG. 5 is a perspective view showing a fixing portion between the front side frame 10 and the load transmission block 11. As shown in FIG. The front side frame 10 is a framework member that supports drivetrain components and suspension members arranged in the front compartment 3, and absorbs the energy of an impact load by collapsing in the front-rear direction when an impact load is applied from the front of the vehicle. As shown in Figs. 2 and 5, a plurality of beads 21 extending in the up-down direction are provided on the left and right side walls of the front side frame 10. The plurality of beads 21 are arranged on the side walls of the front side frame 10 at intervals in the front-rear direction. The plurality of beads 21 encourage the front side frame 10 to undergo a bellows-like collapsing deformation when an impact load is applied. The beads 21 extending in the vertical direction are provided only from the intermediate region to the front region in the front-rear direction of the side wall of the front side frame 10. A plurality of beads 22 extending in the front-rear direction are provided in the rear region of the side wall of the front side frame 10. The beads 22 extending in the front-rear direction restrict deformation of the rear region of the front side frame 10 at the initial stage of collapse when an impact load is input.

[0033] The load transmission block 11 is formed symmetrically as shown in Fig. 3. The load transmission block 11 is provided with a damper housing portion 15, a frame fixing portion 17, a connection wall 19, and a floor fixing portion 18 in each of its left and right regions. The load transmission block 11 having these elements is integrally cast from, for example, aluminum. In other words, the load transmission block 11 is an integrally cast part having the above-mentioned components.

[0034] As described above, the damper housing portion 15 is a portion that supports the upper portion of the damper of the front suspension, and is disposed above the front side frame 10 and on the outer side of the front side frame 10 in the vehicle width direction, as shown in Fig. 1. The damper housing portion 15 is formed in a downward bowl shape (a downward cylindrical shape with a bottom), and the damper is disposed on the lower side (inside) of the bowl-shaped portion. The top of the damper housing portion 15 supports the upper portion of the damper of the front suspension.

[0035] As described above, the damper housing portion 15 is connected to the base portions of the corresponding left and right upper members 7 by bolting or the like. In addition, the cowl top panel 14 is mounted on the left and right damper housing portions 15 connected to the upper members 7. The left and right end portions of the cowl top panel 14 are connected to the corresponding left and right damper housing portions 15 by bolting or the like.

[0036] The frame fixing portion 17 is connected to the lower side of the side wall 15s on the inner side in the vehicle width direction of the damper housing portion 15. The frame fixing portion 17 is a portion for fixing the rear portion of the front side frame 10, and is formed in a block shape of a substantially rectangular parallelepiped extending in the front-rear direction of the vehicle body. As shown in FIG. 4, the block portion of the frame fixing portion 17 is provided with a frame insertion portion 30 having a square shape in a front view into which the rear region of the front side frame 10 is inserted. The frame insertion portion 30 opens toward the front side of the vehicle, and a rib 31 for receiving a load is protruding from the bottom portion on the opposite side to the opening side. The rib 31 is a load supporting wall protruding from the bottom wall 30a of the frame insertion portion 30 toward the front side of the vehicle, and two rib pieces intersect to form an X-shape in a front view. The front end surface of the rib 31 is formed so as to be flat over the entire area. When the front side frame 10 is inserted into the frame insertion portion 30, the front end surface of the rib 31 faces the rear end surface of the front side frame 10 with a small gap therebetween. If the rear of the front side frame 10 attempts to move backward when an impact load is input from the front, the rear end face of the front side frame 10 abuts against the front surface of the rib 31. This restricts the front side frame 10 from being displaced backward excessively.

[0037] Fig. 6 is an enlarged cross-sectional view of a portion of Fig. 4. Fig. 7 is a front view of the front side frame 10 and the fixing portion of the load transmission block 11, with the front side frame 10 cross-sectional along the line VII-VII in Fig. 4. Fig. 8 is a plan view of the front side frame 10 cross-sectional along the line VIII-VII in Fig. 7. A load support wall 32 is provided on the front side of the block portion of the frame fixing portion 17, the load support wall 32 being continuous with the upper opening edge of the frame insertion portion 30. The load support wall 32 is a flat wall perpendicular to the front-rear direction of the vehicle body, and stands vertically upward from the upper opening edge of the frame insertion portion 30.

[0038] 5 and 7, a surrounding wall 50 is provided on the front surface of the block portion of the frame fixing portion 17, protruding forward from the periphery of an area including the opening of the frame insertion portion 30 and the front surface of the load support wall 32. The surrounding wall 50 is a cylindrical wall having a rectangular shape when viewed from the front, and surrounds the outside of the front side frame 10 protruding forward from the opening of the frame insertion portion 30. The surrounding wall 50 has an upper wall 50u, a lower wall 50l, and left and right side walls 50s, and forms a gap between at least the upper wall 50u and the left and right side walls 50s and the outer peripheral surface of the front side frame 10. This gap forms a crushing receiving space 55 that receives the crushed portion when the front side frame 10 receives an impact load from the front and is crushed in the front-rear direction.

[0039] A bracket 33 having a substantially L-shape in a side view is fixed to the upper surface of the front side frame 10 near the rear by welding or the like. The bracket 33 is fixed to a position on the upper surface of the front side frame 10 forward of a portion inserted into the frame insertion portion 30. An upright piece 33a of the bracket 33 abuts against the front surface of the load support wall 32 of the frame fixing portion 17 and is fixed to the load support wall 32 in this state by a bolt 34 (third fastening member). The shaft portion of the bolt 34 extends along the front-rear direction of the vehicle body, and is fastened to the load support wall 32 to restrict displacement of the front side frame 10 in the front-rear direction of the vehicle body. The bracket 33 is fastened and fixed to the load support wall 32 of the load transmission block 11 from the front-rear direction by the bolt 34 (third fastening member).

[0040] In addition, the rear region of the front side frame 10 inserted (fitted) into the frame insertion portion 30 of the frame fixing portion 17 is fastened to the lower wall and one side wall of the frame insertion portion 30 by multiple bolts 35A, 35B (first fastening member and second fastening member). The bolt 35A (first fastening member) penetrates the bottom wall of the frame insertion portion 30 from top to bottom, and is fastened to a cylindrical nut 36 made of iron-based metal protruding from the upper surface of the bottom wall. Similarly, the bolt 35B (second fastening member) penetrates one side wall of the frame insertion portion 30, and is fastened to a cylindrical nut 36 made of iron-based metal protruding from the inner surface of the side wall. The front side frame 10 is fastened and fixed to the peripheral wall (bottom wall) of the frame insertion portion 30 from the top to bottom direction by the bolt 35A, and is fastened and fixed to the peripheral wall (one side wall) of the frame insertion portion 30 from the vehicle width direction by the bolt 35B.

[0041] 6 to 8, three bolts 35A are provided for fastening the front side frame 10 to the lower wall of the frame insertion portion 30. These bolts 35A are arranged in a staggered manner across the vehicle width in the front-to-rear direction of the front side frame 10. In other words, the bolts 35A are arranged alternately on the left and right sides with the center of the lower wall of the front side frame 10 in the width direction therebetween.

[0042] The bolts 35B for fastening the front side frame 10 to the side wall of the frame insertion section 30 are disposed at two locations on the upper side and two locations on the lower side of the side wall of the front side frame 10. The upper and lower corresponding bolts 35B are disposed at the same position in the front-rear direction. As shown in FIG. 6, the two rear bolts 35B are disposed at a substantially midway position between the rearmost and the central one of the three bolts 35A for fixing the lower wall in the front-rear direction. Similarly, the two front bolts 35B are disposed at a substantially midway position between the central and the frontmost one of the three bolts 35A for fixing the lower wall in the front-rear direction. Therefore, the bolts 35A for fixing the lower wall (first fastening member) and the bolts 35B for fixing the side wall (second fastening member) fasten and fix the front side frame 10 to the frame insertion section 30 at positions offset from each other in the front-rear direction.

[0043] 6 and 7, a reinforcing wall 37 (bulkhead) is provided inside the rear region of the front side frame 10, extending horizontally to connect the left and right side walls of the front side frame 10. The reinforcing wall 37 extends from the rear end of the front side frame 10 to a position forward of the connection between the front side frame 10 and the frame fixing part 17 by the bracket 33 and the bolt 34. The reinforcing wall 37 extends in the front-rear direction so as to straddle the connection between the front side frame 10 and the frame fixing part 17 by the bolts 35A, 35B and the connection between the bracket 33 and the bolt 34. However, it is sufficient that the reinforcing wall 37 extends in the front-rear direction so as to straddle at least the fastening portion of the bolt 35B for fixing the side wall.

[0044] 2 and 3, the floor fixing portion 18 of the load transfer block 11 extends in the vehicle width direction along the front edge of the floor member 12. The floor fixing portion 18 is formed in a long plate shape with sufficient thickness on both the top and bottom. The floor fixing portion 18 is overlapped with the front edge of the floor member 12 and fixed to the floor member 12 by a plurality of bolts.

[0045] The left and right regions of the load transfer block 11, which are symmetrical on the left and right sides, are connected to each other at a floor fixing part 18 in the left region and a floor fixing part 18 in the right region. Specifically, as shown in Fig. 3, the floor fixing part 18 in the left region and the floor fixing part 18 in the right region are connected to each other by a connecting block part 40 at approximately the center in the vehicle width direction.

[0046] The connecting wall 19 of the load transfer block 11 extends substantially along the front surface of the dashboard lower panel 13 disposed at the front of the passenger compartment 2, and connects the frame fixing part 17 to the floor fixing part 18 below it. The connecting wall 19 is formed in a plate shape with sufficient thickness, similar to the above-mentioned floor fixing part 18. The connecting wall 19 smoothly continues to the floor fixing part 18 below so as to form a continuous plate shape.

[0047] The upper end of the connecting wall 19 is connected to the rear lower end of the block portion of the frame fixing portion 17. The connecting wall 19 has a width in the vehicle width direction that expands downward from the connection portion with the frame fixing portion 17 as an apex. In other words, the connecting wall 19 is formed to have a substantially isosceles triangle shape when viewed from the front. The lower end region of the connecting wall 19 where the width expands in a divergent manner is continuous with (connected to) the floor fixing portion 18.

[0048] A plurality of upper reinforcing ribs 20 standing upward and extending in the front-rear direction (diagonally front-rear direction) are provided on the upper surface side of the connecting wall 19. The plurality of upper reinforcing ribs 20 are formed on the upper surface side of the connecting wall 19 so as to be spaced apart in the vehicle width direction and to be parallel to each other.

[0049] 3, a panel fixing portion 23 that is recessed in a stepped shape and has a flat upper surface is formed on the upper surface of the upper region of the connecting wall 19, where the width in the vehicle width direction is narrowed. The dashboard lower panel 13 is fastened and fixed to the panel fixing portion 23.

[0050] <Effects of the embodiment> As described above, in the vehicle body front structure of this embodiment, the front side frame 10 is inserted (fitted) into the frame insertion portion 30 of the load transmission block 11, and in this state, the front side frame 10 and the peripheral wall of the frame insertion portion 30 are fastened and fixed in the up-down direction by the bolt 35A (first fastening member) and in the vehicle width direction by the bolt 35B (second fastening member). Then, the bracket 33 protruding from the front side frame 10 is fastened and fixed to the load support wall 32 of the load transmission block 11 in the front-rear direction by the bolt 34 (third fastening member). Therefore, when an impact load is input from the front, the input load is distributed and supported by the peripheral wall of the frame insertion portion 30 in mutually intersecting directions by the bolts 35A and 35B, and further, the load support wall 32 of the load transmission block 11 can be supported in the front-rear direction by the bolt 34. As a result, when an impact load is input from the front, biased stress is unlikely to act on a part of the peripheral area of ​​the front side frame 10, and the front side frame 10 is unlikely to tilt or bend. Therefore, when the front body structure of this embodiment is adopted, the rear region of the front side frame 10 can be fixed to the load transmission block 11 by fastening members (bolts 35A, 35B, 34), while still achieving smooth crushing of the front side frame 10 when an impact load is input from the front.

[0051] In particular, the vehicle body front structure of this embodiment employs a structure in which bolts 35A (first fastening member) and bolts 35B (second fastening member) penetrate the peripheral wall of frame insertion portion 30 and are fastened and fixed from the outside of the peripheral wall of frame insertion portion 30. This makes it easy to perform the work of fastening bolts 35A and 35B. Furthermore, the vehicle front body structure of this embodiment employs a structure in which a bracket 33 is provided to protrude from the front side frame 10, the bracket 33 is placed on the front surface of the load support wall 32 of the load transmission block 11, and the bracket 33 is fastened and fixed from the front surface side of the load transmission block 11 by the bolt 34. This makes it easy to perform the work of fastening the bolt 34. It is also possible to use a method of fastening the bottom side of the frame insertion portion 30 to the rear end of the front side frame 10 with a bolt (fastening member), but in that case, if one tries to ensure the thickness (protruding height) of the load-receiving portion such as the rib 31, the axial length of the bolt becomes long, making the fastening work difficult. In contrast, when this configuration is adopted, the axial length of the bolt 34 can be shortened, and the fastening work of the bolt 34 can be easily performed from the front side.

[0052] Furthermore, in the vehicle body front structure of this embodiment, the load support wall 32 of the load transmission block 11 stands upward from the edge of the opening of the frame insertion portion 30, and the bracket 33 protrudes upward from the upper surface of the front side frame 10. Therefore, when the bracket 33 is fastened and fixed to the load support wall 32 by the bolt 34 (third fastening member), the rear region of the front side frame 10 is fixed to the load transmission block 11 in a manner that it is suspended from above via the bracket 33. As a result, the rear region of the front side frame 10 is stably supported by the load transmission block 11. Furthermore, when an impact load is input from the front, the rear region of the front side frame 10 is less likely to tilt or bend.

[0053] In addition, in the vehicle front body structure of this embodiment, the load transmission block 11 is provided with an enclosing wall 50 that protrudes forward from the periphery of the opening of the frame insertion portion 30 and surrounds the outer peripheral surface of the front side frame 10. A crushing receiving space 55 that receives the crushed portion when the front side frame 10 is crushed in the front-rear direction is provided between the enclosing wall 50 and the front side frame 10. Therefore, when the front side frame 10 is crushed and deformed from the front side toward the rear end side due to the input of an impact load from the front, the crushed portion is received in the crushing receiving space 55 between the enclosing wall 50 and the front side frame 10 as the crushing progresses. As a result, the rear region of the front side frame 10 is supported by the enclosing wall 50 via the received crushed portion, and the rear region of the front side frame 10 is less likely to bend and deform. Therefore, when this configuration is adopted, the front side frame can be crushed and deformed more smoothly. Furthermore, when this configuration is adopted, a part of the crushable portion received in the crushable receiving space 55 also wraps around to the front side of the load support wall 32. As a result, the backward displacement of the rear region of the front side frame 10 can also be restricted by the abutment between the crushable portion and the load support wall 32. Therefore, the front side frame 10 can be crushed and deformed more smoothly when an impact load is input.

[0054] Furthermore, in the vehicle body front structure of this embodiment, a plurality of bolts 35A are provided for fixing the front side frame 10 to the lower wall of the frame insertion portion 30, and the bolts 35A are arranged in a staggered manner in the vehicle width direction in the front-rear direction. Therefore, when the front side frame 10 is crushed to the rear region when an impact load is input from the front, the peripheral area of ​​each bolt 35A is also deformed from the front to the rear. At this time, since the plurality of bolts 35A are arranged in a staggered manner, the deformed portions of the rear region of the front side frame 10 are distributed to two positions in the vehicle width direction, and deformation is likely to occur alternately at the two positions. Therefore, when this configuration is adopted, it is possible to effectively suppress the collapse or breakage of the front side frame 10 in the later stage of the input of the impact load.

[0055] In addition, in the vehicle body front structure of this embodiment, reinforcing walls 37 extending across the internal space of the front side frame 10 are connected to the left and right side walls of the front side frame 10. The reinforcing walls 37 extend so as to straddle at least the fastening portion of the bolt 35B (second fastening member) in the front-rear direction. Therefore, when an impact load is input from the front, the load transmitted to the left and right side walls of the front side frame 10 can be distributed approximately evenly by the reinforcing walls 37. In particular, in the case of a structure in which only one of the left and right side walls of the front side frame 10 is fastened and fixed to the frame insertion portion 30 by the bolt 35B as in this embodiment, it is possible to prevent stress from concentrating only on one of the left and right side walls of the front side frame 10. Therefore, when this configuration is adopted, it is possible to effectively prevent the front side frame 10 from collapsing in the lateral direction or from breaking during the later stage of input of the impact load.

[0056] In the vehicle front body structure of this embodiment, the bolts 35A (first fastening members) for fixing the front side frame 10 to the bottom wall and the bolts 35B (second fastening members) for fixing the front side frame 10 to the side wall fasten the front side frame 10 to the frame insertion portion 30 at positions offset from each other in the front-rear direction. Therefore, when an impact load is input from the front and the crushing of the front side frame 10 progresses to the rear region, deformation of the circumferential area of ​​the bolts 35A for fixing the bottom wall and deformation of the bolts 35B for fixing the side wall tend to occur alternately. Therefore, when this configuration is adopted, it is possible to effectively suppress the collapse or breakage of the front side frame 10 in the later stage of the input of the impact load.

[0057] The present invention is not limited to the above embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, only one of the left and right side walls of the front side frame 10 is fixed to the frame insertion portion 30 by the bolt 35B, but both the left and right side walls of the front side frame 10 may be fixed to the frame insertion portion 30 by the bolt 35B.

[0058] In the above embodiment, the bolts 35A that fasten the lower wall of the front side frame 10 to the frame insertion portion 30 from the top and bottom directions are arranged in a staggered pattern. However, the bolts 35B that fasten the side walls of the front side frame 10 to the frame insertion portion 30 from the vehicle width direction may also be arranged in a staggered pattern. Note that only the bolts 35B that fasten the side walls of the front side frame 10 to the frame insertion portion 30 from the vehicle width direction may be arranged in a staggered pattern.

[0059] Furthermore, in the above embodiment, the load support wall 32 of the load transfer block 11 stands upward from the edge of the opening of the frame insertion portion 30, and the bracket 33 protrudes upward from the upper surface of the front side frame 10. However, the load support wall 32 may stand sideways or downward from the edge of the opening of the frame insertion portion 30, and the bracket 33 overlapping the load support wall 32 may similarly protrude sideways or downward. In this case as well, the bracket 33 can be fastened to the load support wall 32 by the bolt 34 in the front-rear direction.

[0060] In the above embodiment, the load transmission block 11 is integrally formed with a block in the left region to which the left front side frame 10 is fixed and a block in the right region to which the right front side frame 10 is fixed. However, the load transmission block may be configured such that the block in the left region and the block in the right region are separate parts. [Explanation of symbols]

[0061] 10…Front side frame 11...Load transfer block 30…Frame insertion section 32...Load supporting wall 33…Bracket 34...Bolt (third fastening member) 35A…Bolt (first fastening member) 35B...Bolt (second fastening member) 37…Reinforced wall 50…Enclosure wall 55...Collapsed reception space

Claims

1. A front side frame extending substantially along a front-to-rear direction on a front side of the vehicle; a load transfer block which is a cast part that connects a rear portion of the front side frame to another frame member, The load transfer block is a frame insertion portion that opens to the front side and into which a rear region of the front side frame is inserted through the opening; A load support wall standing in a direction substantially perpendicular to the front-rear direction from an edge of the opening, a bracket protruding in a direction intersecting with the front-rear direction and abutting against a front surface of the load support wall is provided at a position forward of a portion of the front side frame that is inserted into the frame insertion portion, With a rear region of the front side frame inserted into the frame insertion portion of the load transmission block, the front side frame is fastened and fixed to a peripheral wall of the frame insertion portion from a vertical direction by a first fastening member, and is fastened and fixed to the peripheral wall from a vehicle width direction by a second fastening member, The vehicle body front structure, wherein the bracket is fastened to the load support wall of the load transfer block from the front-rear direction by a third fastening member.

2. The load support wall of the load transfer block rises upward from an edge of the opening, 2. The vehicle front body structure according to claim 1, wherein the bracket stands upward from an upper surface of the front side frame.

3. the load transmission block further includes a surrounding wall that protrudes forward from a periphery of the opening of the frame insertion portion and surrounds an outer peripheral surface of the front side frame, 2. The vehicle front body structure according to claim 1, wherein a crush receiving space is provided between the surrounding wall and the front side frame to receive a crushed portion when the front side frame is crushed in the fore-and-aft direction.

4. The vehicle body front structure according to claim 1, characterized in that at least one of the first fastening members and the second fastening members is provided in plurality and is arranged in a staggered pattern in a direction intersecting the fore-and-aft direction in the fore-and-aft direction.

5. A reinforcing wall is connected to the left and right side walls of the front side frame, the reinforcing wall extending across the internal space of the front side frame, 2. The vehicle body front structure according to claim 1, wherein the reinforcing wall extends across at least the fastening portion of the second fastening member in the front-rear direction.

6. 2. The vehicle front body structure according to claim 1, wherein the first fastening member and the second fastening member fasten and fix the front side frame and the frame insertion portion at positions offset from each other in the front-rear direction.

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