Vehicle floor structure

Abstract

To guarantee the intensity of a floor cross member that intersects a bulging tunnel part of a floor panel.SOLUTION: A floor cross member 24 is bonded to a top surface of a floor panel 14 so that the floor cross member intersects a bulging tunnel part 18. A center part of the floor cross member 24 is formed with a cross member center part 26 made from an aluminum alloy casting, and left and right lateral parts are formed with cross member lateral parts 30 made from a steel plate. A concave part 28 is formed in an undersurface of the floor cross member center part 26 in order to avoid the tunnel part 18. Upper plates 40 of the left and right cross member lateral parts 30 are flush with a substrate 38 of the cross member center part 26. Ends of the upper plates 40 of the left and right cross member lateral parts 30 abut on an abutted surface 32a of the substrate 38 of the cross member center part 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a floor structure of a vehicle, and more particularly to the configuration of a floor cross member which is part of the vehicle body frame structure. [Background technology]

[0002] A known vehicle floor structure includes a pair of rockers extending along the left and right side edges of the vehicle body in the longitudinal direction and a cross structure with a closed cross section whose ends are connected to the left and right rockers. The cross structure is formed by joining a floor panel and a floor cross member with a hat-shaped cross section that extends in the transverse direction. The floor panel has a raised tunnel section extending in the longitudinal direction in the center of the floor in the transverse direction, and the floor cross member intersects with the tunnel section.

[0003] The following Patent Document 1 discloses a floor cross member (35) disposed on a floor panel (16) having a tunnel portion (floor tunnel 66). The floor cross member (35) has a central portion that intersects with the tunnel portion (66) and left and right side portions that are respectively connected to the left and right ends of the central portion. Specifically, the floor cross member (35) includes an upper tunnel reinforcement (76) and a lower tunnel reinforcement (72) disposed above and below the tunnel portion (66) of the floor panel (16), and a left cross member portion (37) and a right cross member portion (38) connected to the left and right ends of the reinforcement. The vehicle (10) disclosed in the following Patent Document 1 is equipped with a battery pack (battery pack 28) under the floor. Note that the component names and symbols in parentheses above are those used in the following Patent Document 1 and are not related to the component names and symbols used in the description of the embodiments of the present application. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-202744 Summary of the Invention [Problem to be solved by the invention]

[0005] The floor cross member that intersects with the raised tunnel section has a recessed portion formed on its underside to accommodate the tunnel section. This reduces the strength of the cross member where it intersects with the tunnel section. In particular, for electric vehicles with a battery pack mounted under the floor, sufficient strength is required of the floor cross member to protect the battery pack from impact loads during a side collision.

[0006] The present invention provides a vehicle floor structure in which the strength of the floor cross member is increased. [Means for solving the problem]

[0007] The vehicle floor structure of the present invention includes a floor panel having a raised tunnel portion extending in the longitudinal direction of the vehicle, and a floor cross-member extending in the transverse direction of the vehicle, with both ends joined to left and right rockers extending along the left and right edges of the floor panel, joined to the upper surface of the floor panel, and intersecting with the tunnel portion. The floor cross-member includes a cross-member central portion made of aluminum alloy casting and having a recess formed on its underside at the portion where it intersects with the tunnel portion to avoid the tunnel portion, and left and right cross-member lateral portions made of steel plate that are respectively connected to the left and right ends of the cross-member central portion on the vehicle widthwise outer side of the tunnel portion. The cross-member central portion has a base plate that is positioned at the same height as the upper plates of the left and right cross-member lateral portions, which extend straight in the transverse direction, and the ends of the upper plates of the left and right cross-member lateral portions abut against the abutting surfaces of the ends of the base plate.

[0008] The base plate in the center of the cross member and the upper plate on the side of the cross member form a surface that extends straight between the left and right rockers, allowing a side collision load applied to one rocker to be efficiently transmitted to the other rocker.

[0009] In the above vehicle floor structure, the cross-member side sections may have a hat-shaped cross section, and when the floor cross-member is viewed from the side in the left-right direction, the cross-member central section may have hat-shaped cross-section portions at both left and right ends that overlap with the hat-shaped cross sections of the cross-member side sections. A side collision load can be transmitted to the cross-member central section by the entire end faces of the cross-member side sections and can be received by the cross-member central section.

[0010] In the above vehicle floor structure, the cross member central portion may have a plurality of lower ribs on its underside that face the side wall of the tunnel section, intersecting the vehicle longitudinal direction. The lower ribs reinforce the portion of the floor cross member where the cross-sectional shape changes.

[0011] In the above vehicle floor structure, the cross member central portion may have a plurality of upper ribs on its upper surface that intersect with the vehicle longitudinal direction, thereby increasing the strength of the floor cross member central portion, particularly its strength against bending in the lateral direction.

[0012] In the above vehicle floor structure, the cross-member central portion may have an overlapping portion that extends laterally from the abutment surface and overlaps the upper side of the cross-member lateral portion, and the overlapping portion, the cross-member lateral portion, and the seat leg portion may be bolted together, thereby increasing the mounting rigidity of the seat. [Effects of the Invention]

[0013] The side collision load applied to one rocker is transmitted to the opposite rocker by the surface of the floor cross member that extends straight in the left-right direction, thereby suppressing deformation of the rocker that is first subjected to the side collision load. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating a cross section of a floor of a vehicle taken perpendicular to the front-rear direction; [Figure 2]FIG. 2 is a schematic plan view of the central portion of the cross member. [Figure 3] 3 is a schematic cross-sectional view of the central portion of the cross member taken along line AA shown in FIG. 2. [Figure 4] FIG. 2 is a schematic bottom view of the central portion of the cross member. [Figure 5] 3 is a schematic cross-sectional view of the central portion of the cross member taken along line BB shown in FIG. 2. [Figure 6] 3 is a schematic cross-sectional view of the central portion of the cross member taken along line CC shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, terms indicating relative positions and orientations such as front, rear, left, right, top, bottom, etc., refer to relative positions and orientations with respect to the vehicle. In addition, in the left-right direction (width direction) of the vehicle, the side closer to the center line extending in the front-rear direction of the vehicle will be referred to as the inside in the vehicle width direction, and the side further away will be referred to as the outside in the vehicle width direction. In each drawing, the arrow FR points forward, the arrow UP points upward, and the arrow LH points leftward.

[0016] FIG. 1 is a cross-sectional view showing a floor 10 of an electric vehicle. Lockers 12 extending in the longitudinal direction are arranged on the left and right sides of the floor 10. The lockers 12 have a closed cross-sectional structure and are part of the vehicle's skeletal structure. A floor panel 14 is arranged between the left and right lockers 12, and the left and right edges of the floor panel 14 are joined to the left and right lockers 12 by welding or other techniques. A battery pack 16 containing batteries that supply power to the electric motor that drives the vehicle is mounted below the floor panel 14. The floor panel 14 has a tunnel section 18 extending in the longitudinal direction through the center of the vehicle in the transverse direction. The tunnel section 18 protrudes upward from a general surface 20 of the floor panel 14, and this protrusion forms a wiring and piping space 22 for wiring and piping between the tunnel section 18 and the battery pack 16. The tunnel section 18 may have a roughly trapezoidal cross-sectional shape and has a horizontally disposed ceiling 18a and inclined side walls 18b arranged on the left and right sides of the ceiling 18a.

[0017] A floor cross member 24 is joined to the floor panel 14. The floor cross member 24 has a hat-shaped cross section and cooperates with the floor panel 14 to form a body frame member extending in the left-right direction with a closed cross section. The floor cross member 24 consists of three sections: a central section and left and right side sections. The central cross member central section 26 is positioned above the tunnel section 18 so as to intersect with it, and is longer than the width (left-right dimension) of the tunnel section 18. In addition, a recess 28 is formed on the underside of the cross member central section 26 to avoid the tunnel section 18, which protrudes upward. The cross member central section 26 may be made of an aluminum alloy casting and may be manufactured by a casting method such as mold casting, die casting, or molten metal forging.

[0018] Cross-member side sections 30 are disposed on the left and right sides of the cross-member central section 26, and are joined to the ends of the cross-member central section 26 by welding, adhesive, or other methods. The cross-member side sections 30 may be made of steel plate, particularly high-tensile steel plate, formed into a hat-shaped cross section. The cross-member side sections 30 are joined to the floor panel 14 by welding or other methods at flanges provided on the lower edge of the hat shape. In addition, the ends of the cross-member side sections 30 on the rocker 12 side are joined to the rocker 12 by welding or other methods.

[0019] Figures 2-4 are schematic diagrams of the cross-member central portion 26, with Figure 2 being a plan view, Figure 3 being a cross-sectional view taken along line AA in Figure 2, and Figure 4 being a bottom view. Figure 5 is a cross-sectional view of the cross-member central portion 26 taken along line BB in Figures 2-4, showing cross-sections of the cross-member central portion 26 and the cross-member side portions 30. Figure 6 is a cross-sectional view of the cross-member central portion 26 taken along line CC in Figures 2-4, showing the general surface 20 of the floor panel 14 and the cross-member side portions 30 to indicate their relative positions.

[0020] On the left and right sides of the recess 28 on the underside of the cross-member central portion 26, end walls 32 are provided at positions away from the recess 28. The end walls 32 are positioned so as to intersect in the left-right direction. The ends of the cross-member side portions 30 abut against the outer surfaces of the end walls 32 in the vehicle width direction. The surfaces of the end walls 32 against which the cross-member side portions 30 abut are referred to as abutted surfaces 32a. The cross-member central portion 26 further has overlapping portions 36 that extend outward in the vehicle width direction from the end walls 32 and overlap the ends of the cross-member side portions 30. The portion of the cross-member central portion 26 other than the overlapping portions 36, i.e., the portion from one end wall 32 to the other end wall 32, is referred to as a central portion main body 34. As shown in Figures 5 and 6, both the central portion main body 34 and the overlapping portions 36 have hat-shaped cross sections. The cross member central portion 26 is joined to the general surface 20 of the floor panel 14 and the tunnel portion 18 by a method such as welding or adhesive at a flange provided at the lower edge of the hat shape.

[0021] As shown in FIG. 1 , the base plate 38 forming the upper edge of the hat shape of the central body 34 and the upper plate 40 forming the upper edge of the hat shape of the cross-member side section 30 are positioned at the same height, and the end of the upper plate 40 abuts against the end surface of the base plate 38, which is part of the abutment surface 32a. As a result, the upper surface of the floor cross-member 24 extends straight in the left-right direction over its entire length. Because the upper surface of the floor cross-member 24 extends straight, when a collision load is applied from the side, the load is efficiently transmitted to the rocker 12 on the opposite side from the collision side. This suppresses deformation of the rocker 12 on the collision side, protecting the battery pack 16.

[0022] FIG. 5 shows a cross section of the overlapping portion 36 of the cross-member central portion 26 and a cross section of the portion of the central portion body 34 adjacent to the end wall 32. The hat-shaped outer contours of the central portion body 34 and the overlapping portion 36 coincide, while the inner contour, represented by a dashed line, of the central portion body 34 is located inside the overlapping portion 36. In other words, the thickness of the cross-member central portion 26 is thicker at the central portion body 34 and thinner at the overlapping portion 36. The inner surface of the overlapping portion 36 is aligned with the outer surface of the cross-member side portion 30. The cross-member central portion 26 is joined to the cross-member side portion 30 at the overlapping portion 36 by a method such as adhesive bonding or welding. As shown in FIG. 1, the cross-member side portion 30 abuts against the abutting surface 32a of the end wall 32 of the cross-member central portion 26. Furthermore, as shown in FIG. 5 , the end faces of the cross-member side portions 30 are located within the thickness range of the central portion body 34 of the cross-member central portion 26. In other words, when the floor cross-member 24 is viewed from the side, the hat-shaped end faces of the cross-member side portions 30 are within the hat-shaped portion of the central portion body 34 and overlap with the hat-shaped portion of the central portion body 34. The entire hat-shaped end of the cross-member side portions 30 abuts against the abutment surface 32a. Because the cross-sectional shapes of the cross-member side portions 30 and the central portion body 34 overlap, a side collision load is transmitted across the entire hat-shaped cross section of the cross-member side portions 30 and the central portion body 34, ensuring reliable transmission between the cross-member side portions 30 and the cross-member central portion 26.

[0023] Three upper ribs 42 extending parallel to each other in the left-right direction are provided on the upper surface of the base plate 38 of the cross-member central portion 26, particularly the base plate 38 of the central portion body. Of the three upper ribs 42, only the central upper rib 42 is shown in FIG. 3 . The length of the upper rib 42, i.e., the left-right dimension, is longer than the left-right dimensions of the tunnel portion 18 and the recess 28. In particular, the left-right dimension of the upper rib 42 may be equal to the left-right dimension of the central portion body 34. The number of upper ribs 42 may be other than three. Two of the three upper ribs 42 may be positioned coincident with the front and rear edges of the base plate 38 of the central portion body, and the remaining one may be positioned in the center of the base plate 38. The upper rib 42 can compensate for the reduced strength of the cross-member central portion 26 due to the recess 28 on the lower surface.

[0024] Lower ribs 44, 46, and 48 are provided on the underside of the base plate 38 of the cross-member central portion 26, particularly the center portion body. The lower rib 44 extends in the left-right direction, and the lower rib 46 extends in the front-rear direction. Furthermore, the lower rib 48 extends diagonally. The lower ribs 44, 46, and 48 are disposed within a space surrounded on three sides by the hat-shaped cross-member central portion 26, and their lower edges, together with the underside of the center portion body 34, define the recess 28 shaped along the tunnel section 18. As shown in FIG. 3 , the lower rib 44 extending in the left-right direction increases in vertical dimension near the end wall 32 and connects to the end wall 32. Where the lower rib 44 connects to the end wall 32, the vertical dimension of the lower rib 44 is the same as that of the end wall 32. Similarly to the lower rib 44, the diagonally extending lower rib 48 also increases in vertical dimension near the end wall 32. In other words, the lower ribs 44, 48 that intersect in the fore-and-aft direction of the vehicle have a higher rib height in the area facing the side wall 18b of the tunnel section 18, reinforcing the area where the vertical dimension of the floor cross member 24 changes.

[0025] As shown in FIG. 1 , the overlapping portion 36 of the cross-member central portion 26 and the end of the cross-member side portion 30 overlapping the overlapping portion 36 are fastened together by welding nuts 50 (hereinafter referred to as nuts 50) fixed to the cross-member side portion 30 and bolts 52 threadedly coupled to the nuts 50. Furthermore, the nuts 50 and bolts 52 fasten and fix the overlapping portion 36, the cross-member side portion 30, and the leg of a seat together. The leg of the seat may specifically be an underrail 54 of a seat track. The seat track includes an underrail 54 fixed to the floor 10 and an upper rail (not shown) that slides relative to the underrail 54. A seat is fixed to the upper rail and is slidable relative to the floor 10 together with the upper rail. While only the left underrail 54 is shown in FIG. 1 , the underrail on the right side is similarly fastened together to the cross-member side portion 30 and the overlapping portion 36 of the cross-member central portion 26. By fixing the seat legs to the casting part, which is thicker than the steel plate, the mounting rigidity of the seat can be increased.

[0026] By using aluminum alloy casting, which is thicker than steel plate and has a high degree of freedom in shape, for the portion of the floor cross member 24 where it intersects with the tunnel portion 18, the strength of the floor cross member 24 can be increased. In addition, the position of the top surface of the floor cross member 24, which extends straight between the left and right rockers 12, can be lowered, and the height of the cross member side portions 30 can be kept low. This ensures sufficient foot space for passengers on the left and right sides of the tunnel portion 18.

[0027] The above-described embodiment describes an electric vehicle in which a battery pack 16 that supplies power to an electric motor for driving the vehicle is mounted under the floor 10, but the above-described floor structure can also be applied to the floor structure of a vehicle driven by an engine. [Explanation of symbols]

[0028] 10 floor, 12 locker, 14 floor panel, 16 battery pack, 18 tunnel section, 20 general surface of floor panel, 22 wiring and piping space, 24 floor cross member, 26 cross member center section, 28 recess, 30 cross member side section, 32 end wall, 32a abutting surface, 34 central section body, 36 overlapping section, 38 (central section body) base plate, 40 (cross member side section) upper plate, 42 upper rib, 44, 46, 48 lower ribs, 50 welding nut, 52 bolt, 54 under rail.

Claims

1. a floor panel having a raised tunnel portion extending along the vehicle front-rear direction; a floor cross member extending along the left-right direction of the vehicle, with both ends joined to left and right rockers extending along the left and right edges of the floor panel and joined to the upper surface of the floor panel, and intersecting with the tunnel portion, the floor cross member including: a cross member central portion made of aluminum alloy casting that intersects with the tunnel portion and has a recess formed on its underside so as to avoid the tunnel portion; and left and right cross member side portions made of steel plate that are respectively connected to the left and right ends of the cross member central portion on the vehicle width direction outer sides of the tunnel portion; A floor structure for a vehicle comprising: The cross member central portion has a base plate disposed at the same height as the upper plates of the left and right cross member side portions, which extend straight in the left-right direction, and the ends of the upper plates of the left and right cross member side portions abut against the abutted surfaces of the ends of the base plate, The cross-sectional shape of the cross member side portion is hat-shaped, When the floor cross member is viewed from the side in the left-right direction, the cross member central portion has hat-shaped cross-section portions at both left and right ends that overlap with the hat-shaped cross-sections of the cross member side portions, Vehicle floor structure.

2. 2. The vehicle floor structure according to claim 1, The cross member central portion has a plurality of lower ribs that intersect with the vehicle longitudinal direction in an area of ​​the lower surface facing the side wall portion of the tunnel portion. Vehicle floor structure.

3. a floor panel having a raised tunnel portion extending along the vehicle front-rear direction; a floor cross member extending along the left-right direction of the vehicle, with both ends joined to left and right rockers extending along the left and right edges of the floor panel and joined to the upper surface of the floor panel, and intersecting with the tunnel portion, the floor cross member including: a cross member central portion made of aluminum alloy casting that intersects with the tunnel portion and has a recess formed on its underside so as to avoid the tunnel portion; and left and right cross member side portions made of steel plate that are respectively connected to the left and right ends of the cross member central portion on the vehicle width direction outer sides of the tunnel portion; A floor structure for a vehicle comprising: The cross member central portion has a base plate disposed at the same height as the upper plates of the left and right cross member side portions, which extend straight in the left-right direction, and the ends of the upper plates of the left and right cross member side portions abut against the abutted surfaces of the ends of the base plate, The cross member central portion has, on an upper surface thereof, a plurality of upper ribs that intersect with the vehicle longitudinal direction. Vehicle floor structure.

4. a floor panel having a raised tunnel portion extending along the vehicle front-rear direction; a floor cross member extending along the left-right direction of the vehicle, with both ends joined to left and right rockers extending along the left and right edges of the floor panel and joined to the upper surface of the floor panel, and intersecting with the tunnel portion, the floor cross member including: a cross member central portion made of aluminum alloy casting that intersects with the tunnel portion and has a recess formed on its underside so as to avoid the tunnel portion; and left and right cross member side portions made of steel plate that are respectively connected to the left and right ends of the cross member central portion on the vehicle width direction outer sides of the tunnel portion; A floor structure for a vehicle comprising: The cross member central portion has a base plate disposed at the same height as the upper plates of the left and right cross member side portions, which extend straight in the left-right direction, and the ends of the upper plates of the left and right cross member side portions abut against the abutted surfaces of the ends of the base plate, The cross member central portion has an overlapping portion that extends laterally from the abutted surface and overlaps the upper side of the cross member side portion, and the overlapping portion, the cross member side portion, and a leg portion of a seat are connected together with bolts. Vehicle floor structure.

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