Vehicle body structure

Abstract

To satisfactorily secure the assembling accuracy of a vehicle body structure while reducing the number of parts.SOLUTION: A vehicle body structure of the present disclosure is the vehicle body structure including a cast component and an impact absorbing member, wherein the cast component includes a projecting part integrally formed so as to function as a joint, and a positioning surface formed around a root of the projecting part, the impact absorbing member includes a part to be fitted to which the projecting part of the cast component is fitted, the projecting part of the cast component is fitted to the part to be fitted so that the end face of the impact absorbing member abuts against the positioning surface, and the projecting part of the cast component fitted to the part to be fitted and the impact absorbing member are mechanically fastened.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle body structure including a cast part and an impact absorbing member. [Background technology]

[0002] A vehicle body structure has been known that includes a floor panel, a rocker extending in the vehicle length direction along the side edges of the floor panel in the vehicle width direction, a torque box extending inward in the vehicle width direction from the front end of the rocker along the front edge of the floor panel in the vehicle length direction, and a front side member extending forward in the vehicle length direction from the torque box (see, for example, Patent Document 1). In this vehicle body structure, the torque box has a front wall and a rear wall that face each other in the vehicle length direction, and an interior space extending in the vehicle width direction is formed between the front wall and the rear wall. The base end portion, including the rear end, of the front side member is located in the interior space of the torque box and is joined by welding to the inner surface of the torque box within the interior space. Another vehicle body structure has been known that includes front and rear frames facing the cabin fore and aft, lateral frames facing the cabin sideways, upper and lower frames facing the cabin up and down, and a joint member fabricated as a single component by aluminum casting (see, for example, Patent Document 2). In this driver's cabin frame structure, the front and rear frames, the lateral frames, and the upper and lower frames are connected by joint members, and the corner portions of the cabin frame are formed by the joint members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-182437 [Patent Document 2] Japanese Patent Application Publication No. 11-091638 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if components are joined by welding, as in the body structure described in Patent Document 1, it becomes impossible to ensure good assembly precision of the body structure due to the effects of thermal distortion. Also, if a dedicated joint member is used, as in the frame structure described in Patent Document 2, the increase in the number of parts leads to an increase in costs.

[0005] Therefore, a main object of the present disclosure is to reduce the number of parts while ensuring good assembly accuracy of the vehicle body structure. [Means for solving the problem]

[0006] The vehicle body structure disclosed herein includes a cast part and an impact absorbing member, wherein the cast part includes a protrusion formed integrally therewith to function as a joint, the impact absorbing member includes a mating portion into which the protrusion of the cast part is fitted, and the protrusion of the cast part fitted into the mating portion and the impact absorbing member are mechanically fastened together.

[0007] In the vehicle body structure disclosed herein, a protrusion functioning as a joint is integrally formed on a cast part, and the protrusion is fitted into a mating portion of the impact absorbing member. The protrusion of the cast part fitted into the mating portion and the impact absorbing member are then mechanically fastened together. By integrally forming a protrusion as a joint on the cast part in this way, the number of parts in the vehicle body structure can be reduced. Furthermore, by mechanically fastening the protrusion of the cast part fitted into the mating portion and the impact absorbing member, it is possible to eliminate thermal distortion that occurs when the two are joined by welding. As a result, it is possible to ensure good assembly precision for the vehicle body structure while reducing the number of parts. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a vehicle body structure according to the present disclosure. [Figure 2] FIG. 1 is an exploded perspective view showing a vehicle body structure according to the present disclosure. [Figure 3] FIG. 1 is a perspective view showing a main part of a vehicle body structure according to the present disclosure. [Figure 4]FIG. 2 is a side view showing a main part of the vehicle body structure of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0010] FIG. 1 is a perspective view showing a vehicle body structure 1 of the present disclosure, and FIG. 2 is an exploded perspective view showing the vehicle body structure 1. As shown in these drawings, the vehicle body structure 1 includes a dash cross member 2, a torque box 3, side members 4, and a suspension tower 5, and constitutes the underbody of a vehicle (not shown). The dash cross member 2 extends in the vehicle width direction near the front wheels of the vehicle. The torque box 3 is formed, for example, by casting an aluminum alloy, and is fixed to the dash cross member 2 via multiple bolts. The side members 4 are connected to the torque box 3 via multiple bolts B34, and function as impact absorbing members (so-called EA members). The suspension tower 5 is formed, for example, by casting an aluminum alloy, and is fixed to the torque box 3 and side members 4 via multiple bolts B35, B45 (see FIG. 2). The torque box 3 and suspension tower 5 may be integrally formed by casting.

[0011] As shown in Fig. 2, the torque box 3 has a plurality of (for example, two in this embodiment) protrusions 31, 32 that function as joints, which are integrally formed by casting. As shown in Fig. 3, the plurality of protrusions 31, 32 each have flat upper and lower surfaces and a semi-cylindrical (tapered) tip, and extend from the main body of the torque box 3 so as to be aligned parallel to one another at intervals in the height direction (vertical direction) of the vehicle. Each of the protrusions 31, 32 also has a plurality of (two in this embodiment) bolt insertion holes 31h, 32h formed therein so as to be parallel to one another and extend in the width direction of the vehicle. The bolt insertion holes 31h, 32h are through holes with an inner diameter that is necessarily and sufficiently larger than the outer diameter of the shank (threaded portion) of the bolt B34 described above.

[0012] Furthermore, around the multiple protrusions 31, 32 of the torque box 3, flat positioning surfaces 33 are formed so as to extend in the vehicle height direction (vertical direction) and width direction. Additionally, as shown in FIG. 4, the torque box 3 has multiple ribs, including ribs 34, 35, 36, 37, and 38, integrally formed by casting. The rib 34 extends from the rear side of the upper protrusion 31 in the direction opposite to the protrusion direction of the protrusion 31. The rib 35 extends parallel to the rib 34 from the rear side of the lower protrusion 32 in the direction opposite to the protrusion direction of the protrusion 32. The rib 36 extends parallel to the ribs 34 and 35 between them in the vertical direction (vehicle height direction) in FIG. 4. The rib 37 is formed above the rib 34 corresponding to the protrusion 31 in FIG. 4, and the rib 38 is formed below the rib 35 corresponding to the protrusion 32 in FIG. 4.

[0013] The side member 4 is formed by extruding an aluminum alloy or the like so as to have an angular (square) figure-eight (or -shaped) cross section. As shown in FIGS. 1 and 2 , the side member 4 includes an outer cylindrical portion 40 having a rectangular cross section and a flat plate portion 40p formed integrally with the outer cylindrical portion 40 so as to divide the interior of the outer cylindrical portion 40 into two hollow portions 41, 42. Furthermore, each side plate portion 40s at the end of the outer cylindrical portion 40 (side member 4) facing the torque box 3 has a plurality of (for example, four in this embodiment) bolt insertion holes 40h formed in the side plate portion 40s so as to align with the bolt insertion holes 31h, 32h of the protrusions 31, 32 of the torque box 3. Each bolt insertion hole 40h may be a circular hole or, for example, an elongated hole extending in the longitudinal direction of the side member 4.

[0014] When assembling the vehicle body structure 1, the protrusion 31 of the torque box 3, which is a cast part, is fitted into the hollow portion 41 of the side member 4, and the protrusion 32 is fitted into the hollow portion 42 of the side member 4. Furthermore, the plate portion 40p of the side member 4 is disposed (inserted) between the two protrusions 31, 32. In this embodiment, the width of each of the protrusions 31, 32 is set slightly smaller than the width of the hollow portions 41, 42 of the side member 4 (the distance between the inner surfaces of the pair of side plate portions 40s), so that each of the protrusions 31, 32 fits snugly into the corresponding hollow portion 41 or 42. Furthermore, the end face of the side member 4, i.e., the outer cylinder portion 40, abuts against a positioning surface 33 formed around the base of the protrusions 31, 32, so that the side member 4 is positioned relative to the torque box 3 in the longitudinal direction of the vehicle. Then, bolts B34 are inserted into the bolt insertion holes 40h of each side plate portion 40s of the side member 4 and the bolt insertion holes 31h, 32h of each protrusion 31, 32, and nuts (not shown) are screwed onto each bolt B34, thereby mechanically fastening each protrusion 31, 32 of the torque box 3 to the side member 4.

[0015] The side member 4 may be positioned in the vehicle height direction (vertical direction) relative to the torque box 3 by a positioning portion (not shown) formed on the torque box 3, or may be positioned in the vehicle height direction (vertical direction) by a suspension tower 5 fastened to the torque box 3 prior to the side member 4. Furthermore, the side member 4 may be positioned in the vehicle height direction (vertical direction) relative to the torque box 3 by abutting the inner top surface that defines the hollow portion 41 of the side member 4 or the lower surface of the plate portion 40p against the flat upper surface of the protrusion 31 or 32.

[0016] As described above, in the vehicle body structure 1, the protrusions 31, 32 that function as joints are formed integrally with the torque box 3, which is a cast part, and each of the protrusions 31, 32 is fitted into one of the hollow portions 41, 42 that serve as fitting portions of the side member 4, which serves as an impact absorbing member. Then, each of the protrusions 31, 32 of the torque box 3 that is fitted into the hollow portion 41 or 42 is mechanically fastened to the side member 4 via a plurality of bolts B34 and nuts.

[0017] In this way, by integrally forming the protrusions 31, 32 as joints with the torque box 3, it is possible to reduce the number of parts of the vehicle body structure 1. Furthermore, by mechanically fastening the protrusions 31, 32 fitted into the hollow portions 41, 42 to the side member 4, it is possible to eliminate thermal distortion that occurs when the two are joined by welding. As a result, it is possible to ensure good assembly accuracy of the vehicle body structure 1 while reducing the number of parts.

[0018] Furthermore, in the vehicle body structure 1, the torque box 3 includes positioning surfaces 33 formed around the bases of the protrusions 31, 32, and each of the protrusions 31, 32 is fitted into a hollow portion 41 or 42 serving as a fitted portion so that the end face of the side member 4 (outer cylindrical portion 40) abuts against the positioning surface 33. This allows the side member 4 to be positioned and fastened to the torque box 3 with high precision, thereby further improving the assembly precision of the vehicle body structure 1.

[0019] Furthermore, in the vehicle body structure 1, the torque box 3 includes at least two protrusions 31, 32. Furthermore, the side member 4 includes a plurality of hollow portions 41, 42 into which the corresponding protrusions 31 or 32 of the torque box 3 are fitted, and a plate portion 40p that separates the plurality of hollow portions 41, 42. Furthermore, the plate portion 40p of the side member 4 is disposed (inserted) between the two protrusions 31, 32. This increases the contact area between the torque box 3 and the side member 4, making it possible to further improve the rigidity of the connection between them and, ultimately, the rigidity of the vehicle body structure 1.

[0020] The torque box 3 also includes a rib 34 extending from the rear side of the protrusion 31 in the direction opposite to the protrusion direction of the protrusion 31, a rib 36 extending from the rear side of the protrusion 32 in the direction opposite to the protrusion direction of the protrusion 32, and a rib 35 facing (in contact with) a plate portion 40p that separates the multiple hollow portions 41, 42 of the side member 4. This improves the rigidity of the torque box 3 and makes it possible for a load applied to the side member 4 to act in a distributed manner on the multiple ribs 34, 35, 36 of the torque box 3.

[0021] 4, in the vehicle body structure 1, the rib 37 faces the top plate portion 40a of the outer tubular portion 40 of the side member 4, which is on the upper side in the figure, and the rib 38 faces the bottom plate portion 40b of the outer tubular portion 40 of the side member 4, which is on the lower side in the figure. This makes it possible for the vehicle body structure 1 to distribute the load applied to the side member 4 to act on the multiple ribs 34-38 of the torque box 3.

[0022] In the vehicle body structure 1, the protrusions 31, 32 and the side member 4 are mechanically fastened via a plurality of bolts B34 and nuts, but this is not a limitation. That is, the protrusions 31, 32 and the side member 4 may be mechanically fastened via flow drill screws (FSD). Furthermore, the torque box 3 as a cast part may include three or more protrusions, and the side member 4 as an impact absorbing member may include two or more plate portions 40p and three or more hollow portions (fitted portions). Furthermore, a cast part connected to the dash cross member 2 may have protrusions that fit into fitted portions of the dash cross member 2. Furthermore, the side member 4 as an impact absorbing member is not limited to being manufactured by extrusion molding, but may also be manufactured by drawing, pressing, roll forming, or the like.

[0023] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0024] The invention of the present disclosure can be used in the vehicle body structure manufacturing industry and the like. [Explanation of symbols]

[0025] 1 Body structure, 2 Dash cross member, 3 Torque box (cast part), 31, 32 Protrusions, 31h, 32h Bolt insertion holes, 33 Positioning surface, 34, 35, 36, 37, 38 Ribs, 4 Side member, 40 Outer cylinder portion, 40a Top plate portion, 40b Bottom plate portion, 40h Bolt insertion hole, 40p Plate portion, 40s Side plate portion, 41 Hollow portion, 42 Hollow portion, 5 Suspension tower.

Claims

1. A vehicle body structure including a cast part and an impact absorbing member, the cast component includes an integrally formed projection to function as a joint; the impact absorbing member includes a fitted portion into which the protrusion of the cast part is fitted, A vehicle body structure in which the projection of the cast part fitted to the fitted portion and the impact absorbing member are mechanically fastened together.

2. The vehicle body structure according to claim 1, the cast component includes a locating surface formed around a base of the protrusion; The protrusion is fitted to the fitted portion so that the end face of the impact absorbing member abuts against the positioning surface.

3. The vehicle body structure according to claim 1 or 2, the cast component includes at least two of the protrusions; The impact absorbing member includes a plurality of mating portions into which corresponding protrusions of the cast part are fitted, and a plate portion that separates the plurality of mating portions, and the plate portion is a vehicle body structure that is disposed between the two protrusions.

4. The vehicle body structure according to claim 3, The cast component includes a rib extending from the rear side of the protrusion in a direction opposite to the protruding direction of the protrusion, and a rib facing the plate portion of the impact absorbing member.

Images