Vehicle frame structure

Abstract

To facilitate molding and quality assurance of side rails while changing an interval between the side rails in a vehicle front-back direction and achieving a lower floor of a vehicle.SOLUTION: A vehicle frame structure 1 includes: a pair of right and left front side rails 3, 3; a pair of right and left center side rails 4, 4; and a front cross member 6 connecting the pair of right and left center side rails 4, 4 at front end portions of the pair of right and left center side rails 4, 4. An interval between the pair of right and left center side rails 4, 4 is larger than an interval between the pair of right and left front side rails 3, 3. Each of the pair of right and left front side rails 3, 3 includes a kickdown portion 32 extending rearward while inclined downward. The pair of right and left front side rails 3, 3 are connected to the front cross member 6.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a frame structure of a vehicle. [Background technology]

[0002] Patent Document 1 describes a vehicle frame structure in which the spacing between side members (side rails) varies in the vehicle longitudinal direction. In the vehicle frame structure described in Patent Document 1, the side members are configured by joining together a first side member, a second side member located in front of or behind the first side member, and a third side member located between the first and second side members. The third side member is inclined in the vehicle width direction so that the spacing between the first side members is greater than the spacing between the second side members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-185947 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for lower vehicle floors in vehicles such as trucks in order to ensure a sufficient load capacity for luggage, etc. In response to this demand, it is conceivable that in the vehicle frame structure described in Patent Document 1, the third side member, which is inclined in the vehicle width direction, is also inclined in the vehicle up-down direction.

[0005] However, in order to tilt the third side member both in the vehicle width direction and the vehicle up-down direction, the third side member needs to be bent three-dimensionally, which poses a problem of difficulty in forming the third side member and ensuring its quality.

[0006] Therefore, an object of the present invention is to provide a vehicle frame structure that allows for easy molding of side rails and ensuring quality while changing the spacing between side rails in the fore-and-aft direction of the vehicle and lowering the vehicle floor. [Means for solving the problem]

[0007] The vehicle frame structure of the present invention comprises a pair of left and right front side rails located at the front of the vehicle, a pair of left and right center side rails located rearward of the pair of left and right front side rails, and a front cross member connecting the pair of left and right center side rails at their front ends, wherein the distance between the pair of left and right center side rails is greater than the distance between the pair of left and right front side rails, each of the pair of left and right front side rails has a kick-down portion that extends rearward while sloping downward, and the pair of left and right front side rails are connected to the front cross member.

[0008] In this vehicle frame structure, a kick-down portion is formed in each of the pair of left and right front side rails, thereby enabling the vehicle to have a lower floor. Furthermore, by connecting the pair of left and right front side rails to the pair of left and right center side rails via a front cross member, the spacing between the side rails in the fore-and-aft direction of the vehicle can be changed without bending the pair of left and right front side rails in the vehicle width direction. In this way, the spacing between the side rails in the fore-and-aft direction of the vehicle can be changed and the vehicle floor can be lowered without having to bend the side rails three-dimensionally, which facilitates the formation of the side rails and ensures their quality.

[0009] The frame structure may further include a front connecting member that connects each of the pair of left and right front side rails to the front cross member while maintaining a gap between them. In this frame structure, each of the pair of left and right front side rails has a kick-down portion, which can easily cause variations in dimensional accuracy. However, the front connecting member connects each of the pair of left and right front side rails to the front cross member while maintaining a gap between them. This allows the gap between each of the pair of left and right front side rails and the front cross member to absorb variations in dimensional accuracy between the pair of left and right front side rails. This further facilitates molding of the side rails and ensuring their quality.

[0010] The front connecting member may have an L-shaped bracket having a first joint portion extending in the vehicle longitudinal direction and joined to each of the pair of left and right front side rails, and a second joint portion extending in the vehicle width direction and joined to the front cross member. In this vehicle frame structure, the first joint portion of the L-shaped bracket extending in the vehicle longitudinal direction is joined to each of the pair of left and right front side rails, and the second joint portion of the L-shaped bracket extending in the vehicle width direction is joined to the front cross member. This increases the connection strength between each of the pair of left and right front side rails and the front cross member. Furthermore, the load transmitted from each of the pair of left and right front side rails to the front cross member can be distributed in the vehicle width direction.

[0011] The front connecting member may have an upper bracket joined to the upper surface of each of the pair of left and right front side rails and the upper surface of the front cross member, and a lower bracket joined to the lower surface of each of the pair of left and right front side rails and the lower surface of the front cross member. In this vehicle frame structure, the upper bracket and the lower bracket are joined to each of the pair of left and right front side rails and the front cross member so as to sandwich each of the pair of left and right front side rails and the front cross member from above and below the vehicle. This increases the connection strength between each of the pair of left and right front side rails and the front cross member and the front connecting member.

[0012] The vehicle frame structure may include a pair of left and right rear side rails located at the rear of the vehicle, and a rear cross member connecting the pair of left and right center side rails at their rear ends, the pair of left and right rear side rails being connected to the rear cross member. In this vehicle frame structure, by connecting the pair of left and right center side rails to the pair of left and right rear side rails via the rear cross member, the spacing between the side rails in the fore-and-aft direction of the vehicle can be changed at the rear of the vehicle.

[0013] The vehicle frame structure may further include a rear connecting member that connects the pair of left and right rear side rails and the rear cross member while the pair of left and right rear side rails are spaced apart. In this vehicle frame structure, the rear connecting member connects the pair of left and right rear side rails and the rear cross member while the pair of left and right rear side rails are spaced apart, so that the gap between the pair of left and right rear side rails and the rear cross member can absorb variations in the dimensional accuracy of each of the pair of left and right rear side rails. This makes it easier to form the side rails and ensure their quality. [Effects of the Invention]

[0014] According to the present invention, it is possible to easily form the side rails and ensure their quality while changing the spacing between the side rails in the fore-and-aft direction of the vehicle and lowering the floor of the vehicle. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a side view showing a frame structure of a vehicle according to an embodiment; [Figure 2] 1 is a plan view showing a frame structure of a vehicle according to an embodiment; [Figure 3] 1 is a side view showing a frame structure of a vehicle according to an embodiment; [Figure 4] 1 is a plan view showing a frame structure of a vehicle according to an embodiment; [Figure 5] FIG. 5 is an enlarged plan view of a portion V shown in FIG. [Figure 6] FIG. 6 is a perspective view of the part shown in FIG. 5 as seen from above. [Figure 7] FIG. 6 is a perspective view of the part shown in FIG. 5 as seen from below. [Figure 8] FIG. 8 is an enlarged plan view of a portion VIII shown in FIG. [Figure 9] FIG. 9 is a perspective view of the part shown in FIG. 8 as seen from above. [Figure 10] FIG. 9 is a perspective view of the part shown in FIG. 8 as seen from below. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0017] Figures 1 and 3 are side views showing the frame structure of a vehicle according to an embodiment. Figures 2 and 4 are plan views showing the frame structure of a vehicle according to an embodiment. Note that Figures 1 and 2 also show parts other than the frame structure, while Figures 3 and 4 show only the frame structure.

[0018] The vehicle frame structure 1 shown in Figs. 1 to 4 is a frame structure applied to a vehicle 2 such as a truck. The vehicle 2 is, for example, an electric vehicle that can run by driving an electric motor (not shown) such as a motor using electrical energy. The electric vehicle may also be capable of running by a drive source other than an electric motor such as an engine. Examples of electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), and battery electric vehicles (BEVs). In Figs. 1 to 4, FR indicates the front in the longitudinal direction of the vehicle, UP indicates the upper side in the vertical direction of the vehicle, and RH indicates the right side in the width direction of the vehicle. In the following description, the front-rear, up-down, and left-right directions refer to the front-rear, up-down, and left-right directions of the vehicle 2. For example, the front-rear direction refers to the front-rear direction in the vehicle longitudinal direction, the up-down direction refers to the up-down direction in the vehicle vertical direction, and the left-right direction refers to the left-right direction in the vehicle width direction.

[0019] The vehicle frame structure 1 comprises a pair of left and right front side rails 3, 3, a pair of left and right center side rails 4, 4, a pair of left and right rear side rails 5, 5, a front cross member 6, a rear cross member 7, a front connecting member 8, and a rear connecting member 9.

[0020] The pair of left and right front side rails 3, 3 are located at the front of the vehicle 2 and are part of side rails extending substantially in the vehicle longitudinal direction. Each of the pair of left and right front side rails 3, 3 is formed, for example, with a rectangular closed cross section and extends substantially in the vehicle longitudinal direction. The pair of left and right front side rails 3, 3 are spaced apart in the vehicle width direction at a first distance D1. In other words, the distance in the vehicle width direction between the left front side rail 3 and the right front side rail 3 is the first distance D1. Cross members 21, 22 connecting the pair of left and right center side rails 4, 4 are joined to the pair of left and right front side rails 3, 3. The cross member 21 is joined to the front ends of the pair of left and right front side rails 3, 3, and the cross member 22 is joined to the pair of left and right front side rails 3, 3 behind the cross member 21.

[0021] Each of the pair of left and right front side rails 3, 3 has a straight portion 31 and a kick-down portion 32. The straight portion 31 is located forward of the pair of left and right front side rails 3, 3 and extends in the longitudinal direction of the vehicle. The kick-down portion 32 is located rearward of the straight portion 31 and extends rearward while sloping downward. In other words, the kick-down portion 32 is sloping in the vertical direction of the vehicle. Therefore, each of the pair of left and right front side rails 3, 3 is lower at the kick-down portion 32. Note that the kick-down portion 32 is sloping only in the vertical direction of the vehicle, not in the width direction of the vehicle.

[0022] The pair of left and right center side rails 4, 4 are located rearward of the pair of left and right front side rails 3, 3 and are part of side rails extending substantially in the longitudinal direction of the vehicle. Each of the pair of left and right center side rails 4, 4 has, for example, a rectangular closed cross section and extends in the longitudinal direction of the vehicle. The pair of left and right center side rails 4, 4 are arranged side by side in the vehicle width direction, spaced apart by a second distance D2. In other words, the distance in the vehicle width direction between the left center side rail 4 and the right center side rail 4 is the second distance D2.

[0023] The pair of left and right rear side rails 5, 5 are located rearward of the pair of left and right center side rails 4, 4 and are part of side rails extending substantially in the longitudinal direction of the vehicle. Each of the pair of left and right rear side rails 5, 5 has, for example, a rectangular closed cross section and extends in the longitudinal direction of the vehicle. The pair of left and right rear side rails 5, 5 are arranged side by side at a third distance D3 in the vehicle width direction. In other words, the distance in the vehicle width direction between the left rear side rail 5 and the right rear side rail 5 is the third distance D3. Cross members 23, 34 connecting the pair of left and right rear side rails 5, 5 are joined to the pair of left and right rear side rails 5, 5. The cross member 23 is joined to the rear ends of the pair of left and right rear side rails 5, 5, and the cross member 24 is joined to the pair of left and right rear side rails 5, 5 in front of the cross member 23.

[0024] The distance between the pair of left and right center side rails 4,4 is greater than the distance between the pair of left and right front side rails 3,3 and the distance between the pair of left and right rear side rails 5,5. That is, the second distance D2 is greater than the first distance D1 and the third distance D3. The distance between the pair of left and right front side rails 3,3 and the distance between the pair of left and right rear side rails 5,5 may be, for example, approximately the same. That is, the first distance D1 and the third distance D3 may be approximately the same. For example, a front wheel 11 is disposed on the outer side of the pair of left and right front side rails 3,3 in the vehicle width direction. A front suspension module 15 is disposed below the pair of left and right front side rails 3,3. For example, a rear wheel 12 and a rear suspension 13 are disposed on the outer side of the pair of left and right rear side rails 5,5 in the vehicle width direction. For example, a battery 14 for supplying electric energy to the electric motor of the vehicle 2 is disposed on the inner side of the pair of left and right center side rails 4,4 in the vehicle width direction.

[0025] The front cross member 6 has, for example, a rectangular closed cross section and extends in the fore-and-aft direction of the vehicle. The front cross member 6 connects the pair of left and right center side rails 4,4 at their front ends. That is, the left end of the front cross member 6 is joined to the front end of the left center side rail 4, and the right end of the front cross member 6 is joined to the front end of the right center side rail 4. The front cross member 6 can be joined to the pair of left and right center side rails 4,4 by, for example, bolting, welding, or the like.

[0026] The rear cross member 7 has, for example, a rectangular closed cross section and extends in the longitudinal direction of the vehicle. The rear cross member 7 connects the pair of left and right center side rails 4,4 at their rear ends. That is, the left end of the rear cross member 7 is joined to the rear end of the left center side rail 4, and the right end of the rear cross member 7 is joined to the rear end of the right center side rail 4. The rear cross member 7 can be joined to the pair of left and right center side rails 4,4 by, for example, bolting, welding, or the like.

[0027] FIG. 5 is an enlarged plan view of portion V shown in FIG. 4. FIG. 6 is a perspective view of the portion shown in FIG. 5, viewed from above. FIG. 7 is a perspective view of the portion shown in FIG. 5, viewed from below. As shown in FIGS. 1 to 7, the front connecting member 8 connects each of the pair of left and right front side rails 3, 3 to the front cross member 6 while maintaining a gap between them. In other words, each of the pair of left and right front side rails 3, 3 does not abut against the front cross member 6, but is connected to the front cross member 6 via the front connecting member 8. As a result, a gap G1 is formed between each of the pair of left and right front side rails 3, 3 and the front cross member 6. Each of the pair of left and right front side rails 3, 3 and the front cross member 6 is arranged in a T-shape in plan view.

[0028] The front connecting member 8 includes a first L-shaped bracket 81 , a second L-shaped bracket 82 , an outer bracket 83 , an upper bracket 84 , and a lower bracket 85 .

[0029] The first L-shaped bracket 81 connects each of the pair of left and right front side rails 3,3 to the front cross member 6 on the inner side of the pair of left and right front side rails 3,3 in the vehicle width direction. The first L-shaped bracket 81 is disposed on the inner side of the pair of left and right front side rails 3,3 in the vehicle width direction. The first L-shaped bracket 81 is formed in an L shape. The first L-shaped bracket 81 has a first joint portion 81a extending in the vehicle front-rear direction and joined to the inner side surface 3a of each of the pair of left and right front side rails 3,3, and a second joint portion 81b extending in the vehicle width direction and joined to the front side surface 6a of the front cross member 6. The inner side surface 3a extends in the vehicle front-rear direction and is the inner side surface of each of the pair of left and right front side rails 3,3 in the vehicle width direction. The front side surface 6a extends in the vehicle front-rear direction and is the front side surface of each of the pair of left and right front side rails 3,3 in the vehicle front-rear direction. The first L-shaped bracket 81 can be joined to each of the pair of left and right front side rails 3, 3 and the front cross member 6 by, for example, welding.

[0030] The second L-shaped bracket 82 connects each of the pair of left and right front side rails 3,3 to the front cross member 6 on the outer side of the pair of left and right front side rails 3,3 in the vehicle width direction. The second L-shaped bracket 82 is disposed on the outer side of the pair of left and right front side rails 3,3 in the vehicle width direction. The second L-shaped bracket 82 is formed in an L shape. The second L-shaped bracket 82 has a first joint portion 82a extending in the vehicle front-rear direction and joined to the outer side surface 3b of each of the pair of left and right front side rails 3,3, and a second joint portion 82b extending in the vehicle width direction and joined to the front side surface 6a of the front cross member 6. The outer side surface 3b is the outer side surface of each of the pair of left and right front side rails 3,3 in the vehicle width direction. The second L-shaped bracket 82 can be joined to each of the pair of left and right front side rails 3,3 and the front cross member 6 by, for example, welding.

[0031] The outer bracket 83 is a bracket that connects each of the pair of left and right front side rails 3,3 to the front cross member 6 on the outer side of the pair of left and right front side rails 3,3 in the vehicle width direction. The outer bracket 83 is arranged on the outer side of the pair of left and right front side rails 3,3 in the vehicle width direction so as to cover the second L-shaped bracket 82. The outer bracket 83 has a first joint portion 83a that extends in the vehicle front-rear direction and is joined to the outer side surface 3b of each of the pair of left and right front side rails 3,3, and a second joint portion 83b that extends in the vehicle width direction and is joined to the front side surface 6a of the front cross member 6. The outer bracket 83 can be joined to each of the pair of left and right front side rails 3,3 and the front cross member 6 by, for example, welding.

[0032] The upper bracket 84 is a bracket that connects each of the pair of left and right front side rails 3, 3 to the front cross member 6 above the pair of left and right front side rails 3, 3 in the vehicle up-down direction. The upper bracket 84 is disposed above each of the pair of left and right front side rails 3, 3 and the front cross member 6. The upper bracket 84 is disposed so as to cover at least a portion of the second L-shaped bracket 82 and the outer bracket 83 from above. The upper bracket 84 is joined to the upper surface 3c of each of the pair of left and right front side rails 3, 3 and to the upper surface 6b of the front cross member 6. The joining of the upper bracket 84 to each of the pair of left and right front side rails 3, 3 and the front cross member 6 can be performed by, for example, welding.

[0033] The lower bracket 85 is a bracket that connects each of the pair of left and right front side rails 3, 3 to the front cross member 6 below the pair of left and right front side rails 3, 3 in the vehicle up-down direction. The lower bracket 85 is disposed below each of the pair of left and right front side rails 3, 3 and the front cross member 6. The lower bracket 85 is disposed so as to cover the second L-shaped bracket 82 from below. The lower bracket 85 is joined to the lower surface 3d of each of the pair of left and right front side rails 3, 3 and the lower surface 6c of the front cross member 6. The joining of the lower bracket 85 to each of the pair of left and right front side rails 3, 3 and the front cross member 6 can be performed by, for example, welding.

[0034] FIG. 8 is an enlarged plan view of portion VIII shown in FIG. 4. FIG. 9 is a perspective view of the portion shown in FIG. 8 as viewed from above. FIG. 10 is a perspective view of the portion shown in FIG. 8 as viewed from below. As shown in FIGS. 1 to 4 and 8 to 10, the rear connecting member 9 connects each of the pair of left and right rear side rails 5, 5 to the rear cross member 7 while maintaining a gap between them. In other words, each of the pair of left and right rear side rails 5, 5 does not abut against the rear cross member 7, but is connected to the rear cross member 7 via the rear connecting member 9. As a result, a gap G2 is formed between each of the pair of left and right rear side rails 5, 5 and the rear cross member 7. Each of the pair of left and right rear side rails 5, 5 and the rear cross member 7 is arranged in a T-shape in plan view.

[0035] The rear connecting member 9 includes a first L-shaped bracket 91 , a second L-shaped bracket 92 , an inner bracket 93 , an upper bracket 94 , and a lower bracket 95 .

[0036] The first L-shaped bracket 91 is a bracket that connects each of the pair of left and right rear side rails 5, 5 to the rear cross member 7 on the inner side of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The first L-shaped bracket 91 is disposed on the inner side of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The first L-shaped bracket 91 is formed in an L shape. The first L-shaped bracket 91 has a first joint portion 91a that extends in the vehicle front-rear direction and is joined to the inner side surface 5a of each of the pair of left and right rear side rails 5, 5, and a second joint portion 91b that extends in the vehicle width direction and is joined to the rear side surface 7a of the rear cross member 7. The inner side surface 5a extends in the vehicle front-rear direction and is the inner side surface of each of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The rear side surface 7a extends in the vehicle front-rear direction and is the rear side surface of each of the pair of left and right rear side rails 5, 5 in the vehicle front-rear direction. The first L-shaped bracket 91 can be joined to each of the pair of left and right rear side rails 5, 5 and the rear cross member 7 by, for example, welding.

[0037] The second L-shaped bracket 92 is a bracket that connects each of the pair of left and right rear side rails 5, 5 to the rear cross member 7 on the outer side of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The second L-shaped bracket 92 is disposed on the outer side of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The second L-shaped bracket 92 is formed in an L shape. The second L-shaped bracket 92 has a first joint portion 92a that extends in the vehicle front-rear direction and is joined to the outer side surface 5b of each of the pair of left and right rear side rails 5, 5, and a second joint portion 92b that extends in the vehicle width direction and is joined to the rear side surface 7a of the rear cross member 7. The outer side surface 5b is the outer side surface of each of the pair of left and right rear side rails 5, 5 in the vehicle width direction. The second L-shaped bracket 92 can be joined to each of the pair of left and right rear side rails 5, 5 and the rear cross member 7 by, for example, welding.

[0038] The inner bracket 93 is a bracket that connects each of the pair of left and right rear side rails 5,5 to the rear cross member 7 on the inner side of the pair of left and right rear side rails 5,5 in the vehicle width direction. The inner bracket 93 is arranged on the inner side of the pair of left and right rear side rails 5,5 in the vehicle width direction so as to cover the first L-shaped bracket 91. The inner bracket 93 has a first joint portion 93a that extends in the front-to-rear direction of the vehicle and is joined to the inner surface 5a of each of the pair of left and right rear side rails 5,5, and a second joint portion 93b that extends in the vehicle width direction and is joined to the rear surface 7a of the rear cross member 7. The inner bracket 93 can be joined to each of the pair of left and right rear side rails 5,5 and the rear cross member 7 by, for example, welding.

[0039] The upper bracket 94 is a bracket that connects each of the pair of left and right rear side rails 5, 5 to the rear cross member 7 above the pair of left and right rear side rails 5, 5 and the rear cross member 7. The upper bracket 94 is arranged above the pair of left and right rear side rails 5, 5 and the rear cross member 7. The upper bracket 94 is arranged so as to cover at least a portion of the first L-shaped bracket 91, the second L-shaped bracket 92, and at least a portion of the inner bracket 93 from above. The upper bracket 94 is joined to the upper surface 5c of each of the pair of left and right rear side rails 5, 5 and to the upper surface 6b of the rear cross member 7. The joining of the upper bracket 94 to each of the pair of left and right rear side rails 5, 5 and the rear cross member 7 can be performed by, for example, welding.

[0040] The lower bracket 95 is a bracket that connects each of the pair of left and right rear side rails 5, 5 to the rear cross member 7 on the underside of each of the pair of left and right rear side rails 5, 5 and the rear cross member 7. The lower bracket 95 is arranged on the underside of each of the pair of left and right rear side rails 5, 5 and the rear cross member 7. The lower bracket 95 is arranged so as to cover at least a portion of the first L-shaped bracket 91 and the second L-shaped bracket 92 from below. The lower bracket 95 is joined to the underside 5d of each of the pair of left and right rear side rails 5, 5 and the underside 7c of the rear cross member 7. The joining of the lower bracket 95 to each of the pair of left and right rear side rails 5, 5 and the rear cross member 7 can be performed by, for example, welding.

[0041] As described above, in the vehicle frame structure 1 according to this embodiment, the pair of left and right front side rails 3, 3 are each provided with a kick-down portion 32, thereby enabling the vehicle 2 to have a lower floor. Furthermore, by connecting the pair of left and right front side rails 3, 3 to the pair of left and right center side rails 4, 4 via the front cross member 6, the spacing between the side rails in the fore-and-aft direction of the vehicle can be changed without bending the pair of left and right front side rails 3, 3 in the vehicle width direction. In this way, the spacing between the side rails in the fore-and-aft direction of the vehicle can be changed and the vehicle floor can be lowered without three-dimensionally bending the side rails, which facilitates the formation of the side rails and ensures their quality.

[0042] Furthermore, because each of the pair of left and right front side rails 3, 3 has a kickdown portion 32, variations in dimensional accuracy are likely to occur. However, the front connecting member 8 connects each of the pair of left and right front side rails 3, 3 to the front cross member 6 while maintaining a gap between them. Therefore, the gap G1 between each of the pair of left and right front side rails 3, 3 and the front cross member 6 can absorb variations in dimensional accuracy of each of the pair of left and right front side rails 3, 3. This further simplifies the molding of the side rails and ensures their quality.

[0043] Furthermore, in the front connecting member 8, a first joint portion 81a of the first L-shaped bracket 81 and a first joint portion 82a of the second L-shaped bracket 82, which extend in the vehicle longitudinal direction, are joined to each of the pair of left and right front side rails 3, 3, and a second joint portion 81b of the first L-shaped bracket 81 and a second joint portion 82b of the second L-shaped bracket 82, which extend in the vehicle width direction, are joined to the front cross member 6. This increases the connection strength between each of the pair of left and right front side rails 3, 3 and the front cross member 6. Furthermore, the load transmitted from each of the pair of left and right front side rails 3, 3 to the front cross member 6 can be distributed in the vehicle width direction.

[0044] Additionally, the upper bracket 84 and the lower bracket 85 of the front connecting member 8 are joined to the pair of left and right front side rails 3 and the front cross member 6 so as to sandwich the pair of left and right front side rails 3 and the front cross member 6 from the top-to-bottom direction of the vehicle. This increases the connecting strength between the pair of left and right front side rails 3 and the front cross member 6.

[0045] Furthermore, by connecting the pair of left and right center side rails 4, 4 and the pair of left and right rear side rails 5, 5 via the rear cross member 7, the spacing between the side rails in the vehicle longitudinal direction can be changed at the rear side of the vehicle 2.

[0046] Furthermore, the pair of left and right rear side rails 5, 5 and the rear cross member 7 are connected with a gap therebetween by the rear connecting member 9. Therefore, the gap G2 between the pair of left and right rear side rails 5, 5 and the rear cross member 7 can absorb variations in the dimensional accuracy of each of the pair of left and right rear side rails 5, 5. This makes it even easier to form the side rails and ensure their quality.

[0047] Furthermore, in the rear connecting member 9, a first joint portion 91a of the first L-shaped bracket 91 and a first joint portion 92a of the second L-shaped bracket 92, which extend in the vehicle fore-and-aft direction, are joined to each of the pair of left and right rear side rails 5, 5, and a second joint portion 91b of the first L-shaped bracket 91 and a second joint portion 92b of the second L-shaped bracket 92, which extend in the vehicle width direction, are joined to the rear cross member 7. This increases the connection strength between each of the pair of left and right rear side rails 5, 5 and the rear cross member 7.

[0048] Additionally, the upper bracket 94 and the lower bracket 95 of the rear connecting member 9 are joined to the pair of left and right rear side rails 5 and the rear cross member 7 so as to sandwich the pair of left and right rear side rails 5 and the rear cross member 7 from the top-to-bottom direction of the vehicle. This increases the connecting strength between the pair of left and right rear side rails 5 and the rear cross member 7.

[0049] The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment, and may be modified or applied to other things within the scope that does not change the gist described in each claim. [Explanation of symbols]

[0050] 1...frame structure, 2...vehicle, 3...front side rail, 3a...inner surface, 3b...outer surface, 3c...upper surface, 3d...lower surface, 4...center side rail, 5...rear side rail, 5a...inner surface, 5b...outer surface, 5c...upper surface, 5d...lower surface, 6...front cross member, 6a...front side, 6b...upper surface, 6c...lower surface, 7...rear cross member, 7a...rear side, 7c...lower surface, 8...front connecting member, 9...rear connecting member, 11...front wheel, 12...rear wheel, 13...rear suspension, 14...battery, 15...front suspension module, 21...cross member, 22...cross member, 23...cross member, 24...cross member, 31...straight section, 32...kickdown part, 34...cross member, 81...first L-shaped bracket, 81a...first joint, 81b...second joint, 82...second L-shaped bracket, 82a...first joint, 82b...second joint, 83...outer bracket, 83a...first joint, 83b...second joint, 84...upper bracket, 85...lower bracket, 91...first L-shaped bracket, 91a...first joint, 91b...second joint, 92...second L-shaped bracket, 92a...first joint, 92b...second joint, 93...inner bracket, 93a...first joint, 93b...second joint, 94...upper bracket, 95...lower bracket, D1...first distance, D2...second distance, D3...third distance, G1...gap, G2...gap.

Claims

1. A pair of left and right front side rails located at the front of the vehicle; a pair of left and right center side rails located rearward of the pair of left and right front side rails; a front cross member connecting the pair of left and right center side rails at front ends of the pair of left and right center side rails; a front connecting member that connects each of the pair of left and right front side rails to the front cross member while maintaining a space between them, the distance between the pair of left and right center side rails is greater than the distance between the pair of left and right front side rails, Each of the pair of left and right front side rails has a kick-down portion that extends rearward while inclining downward, The pair of left and right front side rails are connected to the front cross member, The front connecting member includes an L-shaped bracket having a first joint portion extending in the vehicle longitudinal direction and joined to each of the pair of left and right front side rails and a second joint portion extending in the vehicle width direction and joined to the front cross member, an upper bracket joined to each upper surface of the pair of left and right front side rails and an upper surface of the front cross member, and a lower bracket joined to each lower surface of the pair of left and right front side rails and a lower surface of the front cross member. Vehicle frame structure.

2. The front connecting member further has outer brackets that connect each of the pair of left and right front side rails to the front cross member on the outer side of the pair of left and right front side rails in the vehicle width direction so as to cover the L-shaped brackets. The vehicle frame structure according to claim 1 .

3. The upper bracket is arranged to cover at least a portion of the L-shaped bracket and the outer bracket from above. The vehicle frame structure according to claim 2.

4. The lower bracket is arranged so as to cover the L-shaped bracket from below but not to cover the outer bracket from below.

4. A vehicle frame structure according to claim 2 or 3.

5. A pair of left and right rear side rails located at the rear of the vehicle; a rear cross member connecting the pair of left and right center side rails at rear ends of the pair of left and right center side rails, The pair of left and right rear side rails are connected to the rear cross member. The vehicle frame structure according to any one of claims 1 to 4.

6. a rear connecting member that connects the pair of left and right rear side rails and the rear cross member in a state where the pair of left and right rear side rails and the rear cross member are spaced apart; The vehicle frame structure according to claim 5.

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