Front body 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 front structure of a vehicle body is one in which a pair of front side frames are arranged on the left and right sides of the front of the vehicle, and the rear of the front side frames are connected to another frame member via a load transmission block (see, for example, Patent Document 1).

[0004] The vehicle front body structure described in Patent Document 1 comprises an upper block whose load transmission block also serves as a strut housing, and a lower block connected to the lower end of the upper block. A fitting hole extending in the fore-and-aft direction is formed between the upper block and the lower block. The upper block and the lower block are integrally formed by casting. The rear region of the 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 portion of the fitting hole on the upper block has a plate-like portion that abuts against a side surface of the rear region of the front side frame, 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 welded to the upper block. At this time, the rear region of the front side frame is positioned inside the fitting hole formed between the upper block and the lower block in a fitted state.

[0006] In this front body structure, the load transfer block is composed of upper and lower cast parts, which reduces the number of components required for the load transfer block. Furthermore, the side surfaces of the rear regions of the front side frames are welded to the plate-shaped portions of the upper blocks, ensuring a large weld area and increasing the support rigidity of the rear regions of the front side frames. This ensures smooth crushing of the front side frames when an impact load is applied from the front of the vehicle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-166853 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the front body structure described in Patent Document 1 requires the load transfer block to be composed of an upper block and a lower block, and the upper block must be formed with a plate-shaped portion for welding and fixing the front side frame. This makes the structure of the load transfer block complex, and the work required to fix the front side frame is also cumbersome. Furthermore, when the load transfer block is made of a cast part, it may be difficult to achieve strong welding depending on the shape of the contact portion 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 transmission block and fixing the rear region of the front side frame to the load transmission block with fastening members.

[0010] However, if the rear region of the front side frame is fixed at multiple discrete locations with fastening members, stress is likely to act unevenly on one part of the periphery of the front side frame when an impact load is applied from the front of the vehicle.When stress acts unevenly on one part of the periphery of the front side frame, this stress can cause the front side frame to tilt or bend, hindering the front side frame from collapsing smoothly (absorbing energy).

[0011] Therefore, the present invention aims to provide a vehicle front body structure that can secure the rear regions of the front side frames to the load transmission blocks with fastening members while ensuring smooth crushing of the front side frames when an impact load is applied from the front, thereby contributing to the development of sustainable transportation systems. [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 longitudinal 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 frame 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 longitudinal direction, and the load transfer block inserted into the frame insertion part of the front side frame In a position forward of the portion where the front side frame is inserted, a bracket (e.g., bracket 33 in the embodiment) is provided that protrudes in a direction intersecting the front-to-rear direction and abuts against the front surface of the load support wall, and with the 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 the peripheral wall of the frame insertion portion from the up-and-down direction by first fastening members (e.g., bolt 35A in the embodiment) and is fastened and fixed to the peripheral wall from the vehicle width direction by second fastening members (e.g., bolt 35B in the embodiment), and the bracket is fastened and fixed to the load support wall of the load transmission block from the front-to-rear direction by third fastening members (e.g., bolt 34 in the embodiment).

[0013] In the vehicle front body structure configured as described above, when an impact load is applied from the front of the front side frame, the load is supported by the peripheral wall of the frame insertion portion of the load transfer block via the first fastening member and the second fastening member. At this time, the input load is distributed and supported by the vertical wall of the frame insertion portion and the horizontal wall of the vehicle via the first fastening member and the second fastening member. The impact load applied to the front side frame is also supported by the load support wall of the load transfer block via 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 distributed and supported by the longitudinal load support wall of the load transfer block. Therefore, when an impact load is applied from the front, uneven stress is less likely to act on a portion of the periphery of the front side frame, making it less likely for the front side frame to tilt or bend.

[0014] The load support wall of the load transmission block may stand upward from an edge of the opening, and the bracket may stand 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 with the third fastening member, the rear region of the front side frame is fixed to the load transfer block by being suspended from above via the bracket. This ensures that the rear region of the front side frame is stably supported by the load transfer block. Furthermore, when a frontal impact load is applied, 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 crushed receiving space (e.g., crushed receiving space 55 in the embodiment) that receives the crushed 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 a front impact load is applied and the front side frame is crushed from its front end toward its rear end, as the crushing progresses, the crushed portion is accommodated in the crush-receiving space between the surrounding wall and the front side frame. This makes it difficult for the rear region of the front side frame to bend and deform when an impact load is applied. Therefore, when this configuration is adopted, the front side frame can be crushed and deformed more smoothly. Furthermore, a portion of the crushable portion received in the crushable receiving space is curved around to the front side of the load-bearing wall. As a result, backward displacement of the rear region of the front side frame is also restricted by the contact between the crushable portion and the load-bearing wall. This allows the front side frame to more smoothly crush and deform when an impact load is applied.

[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 pattern in a direction intersecting the front-rear direction in the front-rear direction.

[0019] In this case, when a front impact load is applied, as the crushing of the front side frame progresses to the rear region, deformation also progresses from the front to the rear in the peripheral areas of each fastening member. In this case, because the fastening members are arranged in a staggered pattern in this configuration, deformation points in the rear region of the front side frame are dispersed to multiple positions in the vehicle width direction and the up-down direction. Therefore, when this configuration is adopted, collapse and fracture of the front side frame can be effectively suppressed in the later stages of the impact load application.

[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 lateral direction in the later stages of the impact load application.

[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 applied, as the crushing of the front side frame progresses to the rear region, the peripheral areas of each fastening member also undergo deformation from front to rear. In this configuration, the first fastening member and the second fastening member are positioned offset from each other in the fore-and-aft direction, making it easier for the peripheral areas of the first fastening member and the second fastening member 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 stages of the impact load application. [Effects of the Invention]

[0024] The vehicle front body structure according to the present invention distributes and supports 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 further supports the load in the front-to-rear direction on the load support wall of the load transfer block by the third fastening member. As a result, when an impact load is input from the front, uneven stress is less likely to act on one part of the peripheral region of the front side frame, making it less likely for the front side frame to tilt or bend. Therefore, when the vehicle front body structure according to the present invention is adopted, it is possible to secure the rear region of the front side frame to the load transfer block with fastening members, while still ensuring smooth crushing of the front side frame when an impact load is input from the front. [Brief explanation of the drawings]

[0025] [Figure 1]FIG. 2 is a perspective view of the front of the vehicle according to the embodiment. [Figure 2] FIG. 2 is a side view of the front part of the vehicle according to the embodiment. [Figure 3] FIG. 2 is a perspective view of the load transmission block according to the embodiment, seen from above the rear side. [Figure 4] 4 is a cross-sectional view of the front of the vehicle corresponding to the cross section IV-IV in FIG. 3 . [Figure 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 section of the front side frame of the embodiment taken along line VII-VII in FIG. 4, showing a fixing portion of the front side frame and the load transmission block. [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 INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In 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 as viewed from the front) are shown at appropriate locations.

[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 seen from the left side. 1 and 2, reference numeral 2 denotes a passenger compartment where passengers ride, and reference numeral 3 denotes a front compartment located in front of the passenger compartment 2 and accommodating a drive motor, engine, etc. Front side frames 10 extending substantially along the longitudinal 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 frame 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 longitudinal direction of the vehicle body are disposed on the left and right sides of the lower portion of the passenger compartment 2. A floor panel 5 disposed below the passenger compartment 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 longitudinal and transverse 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 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 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] Front pillars 6, which form the leading edges of the front door openings, are connected to the front ends of the left and right side sills 4. Upper members 7, which extend substantially along the longitudinal direction of the vehicle body, are connected to the front side of the upper portion of each front pillar 6 at a position outside the front compartment 3 in the vehicle width direction. The upper members 7 curve downward from the left and right front pillars 6 toward the front of the vehicle body, and their front ends extend to positions outside the front ends of the front side frames 10. The front ends of each upper member 7 are connected to the front ends of the corresponding left and right front side frames 10 via connecting members (not shown). Damper housing portions 15 at the left and right upper portions of the load transmission block 11, which will be described in detail later, are connected to the base portions (rear regions) of the left and right upper members 7. The damper housing portions 15 support the upper portions of the dampers of the front suspensions (not shown).

[0031] Fig. 3 is a perspective view of the load transmission block 11 as seen 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 in a rectangular (quadratic) 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 with 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 the 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-to-rear direction when an impact load is applied from the front of the vehicle. As shown in FIGS. 2 and 5, the left and right side walls of the front side frame 10 are provided with a plurality of beads 21 that extend in the up-down direction. The plurality of beads 21 are arranged on the side walls of the front side frame 10 at intervals in the front-to-rear direction. The plurality of beads 21 encourage the front side frame 10 to undergo bellows-like collapsing deformation when an impact load is applied. The beads 21 extending in the vertical direction are provided only in the front-to-rear direction middle to front regions of the side walls of the front side frame 10. A plurality of beads 22 extending in the front-to-rear direction are provided in the rear regions of the side walls of the front side frame 10. These beads 22 extending in the front-to-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] As shown in Fig. 3, the load transmission block 11 is formed in a bilaterally symmetrical shape. The load transmission block 11 has a damper housing portion 15, a frame fixing portion 17, a connecting wall 19, and a floor fixing portion 18 in each of its left and right regions. The load transmission block 11, which has 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 15 is a portion that supports the upper portion of the damper of the front suspension, and as shown in Fig. 1, is disposed above the front side frame 10 and further outward in the vehicle width direction than the front side frame 10. The damper housing 15 is formed in a downward-facing bowl shape (a downward-facing cylindrical shape with a closed bottom), and the damper is disposed below (inside) the bowl-shaped portion. The top of the damper housing 15 supports the upper portion of the damper of the front suspension.

[0035] As described above, the damper housing portions 15 are 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 ends 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 a lower 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 that fixes the rear portion of the front side frame 10 and is formed in a substantially rectangular block shape extending in the front-to-rear direction of the vehicle. As shown in FIG. 4 , the block portion of the frame fixing portion 17 is provided with a frame insertion portion 30 that is rectangular in front view and into which the rear region of the front side frame 10 is inserted. The frame insertion portion 30 opens toward the front of the vehicle, and a load-receiving rib 31 protrudes from the bottom on the side opposite the opening. The rib 31 is a load-bearing wall that protrudes toward the front of the vehicle from the bottom wall 30a of the frame insertion portion 30, and two rib pieces intersect to form an X-shape in front view. The front end surface of the rib 31 is formed flat over its 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 between them. 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 face of the rib 31. This prevents the front side frame 10 from moving backward too much.

[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-sectioned along line VII-VII in Fig. 4. Fig. 8 is a plan view of the front side frame 10 cross-sectioned along 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, and is continuous with the upper opening edge of the frame insertion portion 30. The load support wall 32 is a flat wall that is perpendicular to the fore-and-aft 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 the area where the opening of the frame insertion portion 30 and the front surface of the load support wall 32 meet. The surrounding wall 50 is a cylindrical wall that is rectangular in front view and surrounds the outside of the front side frame 10 that protrudes 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 gaps 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 crushed receiving space 55 that receives the crushed portion when the front side frame 10 is crushed in the fore-and-aft direction due to an impact load from the front.

[0039] A bracket 33, which is generally L-shaped in side view, is fixed by welding or the like to the upper surface of the front side frame 10 near the rear. The bracket 33 is fixed to a position on the upper surface of the front side frame 10 forward of the 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 of the bolt 34 extends along the fore-and-aft direction of the vehicle body, and by tightening it into the load support wall 32, it restricts displacement of the front side frame 10 in the fore-and-aft 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 fore-and-aft 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 that protrudes 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 that protrudes 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 of the side walls) of the frame insertion portion 30 from the vehicle width direction by the bolt 35B.

[0041] 6 to 8, three bolts 35A are provided to fasten the front side frame 10 to the lower wall of the frame insertion portion 30. These multiple bolts 35A are arranged in a staggered pattern across the width of the vehicle in the fore-and-aft direction of the front side frame 10. In other words, the multiple bolts 35A are arranged alternately on the left and right sides with the center of the width direction of the lower wall of the front side frame 10 between them.

[0042] The bolts 35B that fasten the front side frame 10 to the side wall of the frame insertion section 30 are arranged 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 corresponding upper and lower bolts 35B are arranged at the same position in the front-to-rear direction. As shown in FIG. 6, the two rear bolts 35B are arranged at a position approximately midway between the rearmost and central of the three bolts 35A for fastening the lower wall in the front-to-rear direction. Similarly, the two front bolts 35B are arranged at a position approximately midway between the central and frontmost of the three bolts 35A for fastening the lower wall in the front-to-rear direction. Therefore, the bottom wall fastening bolts 35A (first fastening members) and the side wall fastening bolts 35B (second fastening members) fasten and fix the front side frame 10 to the frame insertion section 30 at positions offset from each other in the front-to-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 and connecting the left and right side walls of the front side frame 10. This 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-to-rear direction across the connection between the front side frame 10 and the frame fixing part 17 by the bolts 35A and 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 transmission 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 the shape of a long plate with sufficient thickness at the top and bottom. The floor fixing portion 18 is placed over the front edge of the floor member 12 and is fixed to the floor member 12 with multiple bolts.

[0045] The left and right symmetrical regions of the load transmission block 11 are connected to each other at the floor fixing portion 18 of the left region and the floor fixing portion 18 of the right region. Specifically, as shown in Fig. 3, the floor fixing portion 18 of the left region and the floor fixing portion 18 of the right region are connected to each other by a connecting block portion 40 at approximately the center position 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 width of the connecting wall 19 in the vehicle width direction widens downward from the connection portion with the frame fixing portion 17 as an apex. In other words, the connecting wall 19 is formed so as to form a substantially isosceles triangle when viewed from the front. The lower end region of the connecting wall 19, where the width widens downward, is continuous with (connected to) the floor fixing portion 18.

[0048] A plurality of upper reinforcing ribs 20 that stand upward and extend in the front-rear direction (diagonally front-rear direction) are provided on the upper surface of the connecting wall 19. The plurality of upper reinforcing ribs 20 are formed on the upper surface 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, which 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 this panel fixing portion 23.

[0050] <Effects of the embodiment> As described above, in the vehicle front body 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 together in the vertical direction by bolts 35A (first fastening members) and in the vehicle width direction by bolts 35B (second fastening members). The brackets 33 protruding from the front side frame 10 are fastened together in the front-rear direction to the load support wall 32 of the load transmission block 11 by bolts 34 (third fastening members). Therefore, when an impact load is applied from the front, the applied load is distributed and supported by the peripheral wall of the frame insertion portion 30 in directions intersecting each other by the bolts 35A and 35B, and further supported in the front-rear direction by the load support wall 32 of the load transmission block 11 by the bolt 34. As a result, when an impact load is applied from the front, uneven stress is less likely to act on a portion of the periphery of the front side frame 10, making it less likely for the front side frame 10 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 members) and bolts 35B (second fastening members) 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 fasten bolts 35A and 35B. Furthermore, the vehicle front body structure of this embodiment employs a structure in which brackets 33 are provided to protrude from the front side frames 10, and the brackets 33 are placed on the front surfaces of the load support walls 32 of the load transmission blocks 11, and then fastened and fixed to the front surfaces of the load transmission blocks 11 with bolts 34. This makes it easy to fasten the bolts 34. It is also possible to fasten the bottom 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 you try to ensure the thickness (protrusion height) of the load-bearing 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 bolt 34 can be easily fastened 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 top surface of the front side frame 10. Therefore, when the bracket 33 is fastened to the load support wall 32 with bolts 34 (third fastening members), 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, tilting or bending of the rear region of the front side frame 10 is more unlikely to occur.

[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 crushable receiving space 55 is provided between the enclosing wall 50 and the front side frame 10 to receive a crushed portion when the front side frame 10 is crushed in the longitudinal direction. Therefore, when the front side frame 10 is crushed from its front end toward its rear end due to the input of a frontal impact load, the crushed portion is received in the crushable 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 crushable portion, making it less likely for the rear region of the front side frame 10 to bend or deform. Therefore, when this configuration is adopted, the front side frame can be crushed and deformed more smoothly. Furthermore, when this configuration is adopted, 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, backward displacement of the rear region of the front side frame 10 can be restricted by the contact between the crushable portion and the load support wall 32. Therefore, the front side frame 10 can be more smoothly crushed and deformed when an impact load is input.

[0054] Furthermore, the vehicle front body structure of this embodiment includes multiple bolts 35A that secure the front side frame 10 to the lower wall of the frame insertion portion 30. The bolts 35A are arranged in a staggered pattern in the vehicle width direction in the longitudinal direction. Therefore, when a front impact load is applied, as the front side frame 10 is crushed to its rear region, deformation also progresses from front to rear in the periphery of each bolt 35A. Because the multiple bolts 35A are arranged in a staggered pattern, deformation in the rear region of the front side frame 10 is dispersed to two positions in the vehicle width direction, and deformation is more likely to occur alternately between the two positions. Therefore, when this configuration is adopted, collapse and fracture of the front side frame 10 can be effectively suppressed in the later stages of the impact load application.

[0055] Furthermore, in the vehicle front body structure of this embodiment, reinforcing walls 37 extending across the interior 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 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, stress can be prevented from concentrating on only 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 left-right direction or breaking in the later stage of input of the impact load.

[0056] Furthermore, in the vehicle front body structure of this embodiment, the bolts 35A (first fastening members) for securing the front side frame 10 to the bottom wall and the bolts 35B (second fastening members) for securing the front side frame 10 to the frame insertion portion 30 are fastened to each other at positions offset from each other in the front-to-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 areas of the bolts 35A for securing the bottom wall and the bolts 35B for securing the side wall tend to occur alternately. Therefore, when this configuration is adopted, collapse or breakage of the front side frame 10 can be effectively suppressed in the later stages of 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 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 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 top 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 superimposed on 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 in the front-rear direction with the bolts 34.

[0060] In the above embodiment, the load transmission block 11 is integrally formed with a left region block to which the left front side frame 10 is fixed and a right region block to which the right front side frame 10 is fixed. However, the load transmission block may be configured such that the left region block and the right region block 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...Collapse receptor space

Claims

1. a front side frame extending substantially along the 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 transmission 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; a load support wall that stands upright from the edge of the opening in a direction substantially perpendicular to the front-rear direction, a bracket protruding in a direction intersecting 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 first fastening members and to the peripheral wall from a vehicle width direction by second fastening members, The bracket is attached to the load support wall of the load transmission block from the front-rear direction by a third fastening portion It is fastened and fixed by the material, the load transmission block further includes a surrounding wall that protrudes forward from a periphery of the opening in the frame insertion portion and surrounds an outer peripheral surface of the front side frame, A vehicle front body structure, characterized in that a crushable 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.

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

3. At least one of the first fastening member and the second fastening member is provided in plurality, 2. The vehicle body front structure according to claim 1, wherein the front and rear wheels are arranged in a staggered manner in a direction intersecting the longitudinal direction.

4. Reinforcing walls are connected to the left and right side walls of the front side frame, the reinforcing walls extending across the interior 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.

5. 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 fore-and-aft direction.

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