JP2023049314A - Underfloor structure of vehicle - Google Patents

Abstract

To upgrade the rigidity of a part in which both a step lengthwise frame and a seat fixation frame are employed due to a difference in the height of a floor surface, and upgrade the fixation stability of a seat to be ensured at the time of a vehicle collision.SOLUTION: In an underfloor structure of a vehicle, a second underfloor frame adjacent to a first underfloor frame is located at a position lower than the first underfloor frame is. A foremost seat fixation frame 30f coupled to the second underfloor frame is located below a lower panel part 13f of a floor panel 13. A step lengthwise frame 40 that links the first underfloor frame to an end of the foremost seat fixation frame is located below a corner at which an upper panel part 13u and a step part 13d of the floor panel meet. Further, the first underfloor frame, step lengthwise frame, and foremost seat fixation frame are coupled to one another with a reinforcement member 50 that straddles the step lengthwise frame and foremost seat fixation frame from the first underfloor frame.SELECTED DRAWING: Figure 3

Description

The present invention includes a plurality of underfloor frames that extend in the vehicle width direction below a floor panel of a vehicle and are provided at intervals in the vehicle front-rear direction; The present invention relates to a vehicle underfloor structure including a plurality of fixed seat fixing frames.

Japanese Patent Laid-Open No. 2002-200000 describes a technique related to the arrangement of seats in a vehicle such as a bus. In general, as shown in FIG. 14, a small bus 100 or the like has an engine or the like installed under the front floor, so that a front floor 110 (hereinafter referred to as a front floor 110) where a driver's seat 101 is located. The floor 112 on which the passenger seats 102 are installed (hereinafter referred to as the passenger compartment floor 112) is located one step lower than the front floor 110. As shown in FIG. Here, as shown in FIG. 15, a rectangular groove-shaped underfloor frame 121 is provided under the floor so as to extend in the vehicle width direction below the passenger compartment floor material 112p. A plurality of underfloor frames 121 are provided at intervals in the longitudinal direction of the vehicle. A plurality of seat fixing frames 124m and 124f are provided on the lower side of the passenger compartment floor material 112p to extend in the longitudinal direction of the vehicle by connecting the underfloor frames 121 to each other and to which the leg portions 102k of the seat 102 are fixed. ing.

Here, since the plurality of underfloor frames 121 installed on the passenger compartment floor 112 are positioned at the same height, the front and rear underfloor frames 121 on the passenger compartment floor 112 are connected to each other by the linear main seat fixing frames 124m. be. On the other hand, the underfloor frame 121 (first underfloor frame 121) installed on the front floor surface 110 and the foremost underfloor frame 121 (second underfloor frame) installed on the floor surface 112 of the passenger compartment have a height are different, they cannot be connected with the linear main seat fixing frame 124m. For this reason, as shown in FIG. 15, the first underfloor frame 121 and the second underfloor frame 121 generally connect the vertical step vertical frame 126 and the frontmost seat fixing frame 124f. are connected by

JP-A-2004-98880

However, the configuration in which the first underfloor frame 121 and the second underfloor frame 121 are connected by the vertical step frame 126 and the frontmost seat fixing frame 124f does not allow the front and rear underfloor frames to be connected by the linear main seat fixing frame 124m. Rigidity is lowered compared to the configuration in which the frames 121 are connected. For this reason, for example, when a vehicle crashes, as indicated by the two-dot chain line in FIG. and the front seat fixing frame 124f, the first underfloor frame 121 cannot receive the load F effectively. Further, when the seat 102 is tilted forward, the front surface of the leg portion 102k of the seat 102 cannot be efficiently supported by the passenger compartment floor material 112p and the vertical step frame 126. - 特許庁That is, the fixing stability of the seat at the time of vehicle collision is lowered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. To improve the fixing stability of a seat at the time of a vehicle collision by improving the rigidity of a seat.

The above problems are solved by each invention. A first invention comprises a plurality of underfloor frames provided in parallel under a floor panel of a vehicle, and a plurality of underfloor frames extending in a direction intersecting with the underfloor frame under the floor panel. An underfloor structure for a vehicle comprising a plurality of seat fixing frames to which leg portions of seats are fixed, the underfloor frames being interconnected, wherein the second underfloor frame adjacent to the first underfloor frame is the above-described seat fixing frame. Located at a position lower than the first underfloor frame, the floor panel includes an upper panel portion covering the first underfloor frame, a lower panel portion covering the second underfloor frame, the upper panel portion and the lower portion. A step portion between the panel portions is provided, and the predetermined seat fixing frame connected to the second underfloor frame is provided below the lower panel portion of the floor panel, A step vertical frame connecting the first underfloor frame and an end of the predetermined seat fixing frame is provided below a corner portion between the upper panel portion of the floor panel and the step portion, Further, the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame are reinforcing members spanning the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame. are interconnected by

According to the present invention, the upper first underfloor frame and the lower second underfloor frame are connected via the vertical step frame and the predetermined seat fixing frame. Further, the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame are connected to each other by a reinforcing member extending from the first underfloor frame to the vertical step frame and the predetermined seat fixing frame. there is That is, since the connecting portion between the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame is reinforced by the reinforcing member over the entirety, the first underfloor frame, the vertical step frame, and the seat fixing are reinforced. The rigidity of the connection part with the front part of the frame is increased. As a result, when the seat tilts forward in the event of a frontal collision of the vehicle, when a downward load is applied from the legs of the seat to the predetermined seat fixing frame, the load can be effectively absorbed by the first underfloor frame. Can receive. Furthermore, when the seat is tilted forward, the front surface of the leg of the seat can be supported by the stepped portion of the floor panel whose rigidity is improved by the vertical step frame and the reinforcing member. As a result, it is possible to prevent the seat from tilting forward in the event of a frontal collision of the vehicle. That is, the fixing stability of the seat at the time of vehicle collision is improved.

According to the second aspect of the invention, the underfloor frame is a frame extending in the vehicle width direction, the seat fixing frame is a frame extending in the vehicle front-rear direction, and the predetermined seat fixing frame has a front end that is a vertical step frame. and its rear end is connected to the second underfloor frame.

According to the third aspect of the invention, the underfloor frame is formed in a groove shape, flange portions are formed on both sides of the opening of the groove, the reinforcing member is a plate-shaped molding, and the first underfloor frame is It is joined to the flanges in a state of being superimposed on the flanges on both sides. That is, the reinforcing member is joined to the flange portion of the first underfloor frame while covering the first underfloor frame together with the floor panel from above.

According to the fourth invention, the step vertical frame and the reinforcing member are joined together to form a hollow closed cross section. That is, the step vertical frame and the reinforcing member are joined together to form the tubular portion, so that the rigidity of the joined body of the step vertical frame and the reinforcing member is increased.

According to the fifth invention, the vertical frame for steps is formed in a groove shape extending in the vertical direction, flange portions are formed on both sides of the opening of the groove, and the reinforcing members are provided on both sides of the vertical frame for steps. It is joined to the flange portions while being superimposed on the flange portions.

According to the sixth invention, the reinforcing member has a bead extending vertically at a position covering the space in the groove of the vertical step frame. In this way, the bead works to increase the rigidity in the vertical direction of the joined body between the vertical step frame and the reinforcing member.

According to the present invention, since the rigidity of the portion where the vertical step frame and the seat fixing frame are used can be improved due to the difference in the height of the floor surface, the fixing stability of the seat in the event of a vehicle collision is improved. do.

1 is a schematic side view of a vehicle having an underfloor structure according to Embodiment 1 of the present invention; FIG. FIG. 2 is an enlarged view in the direction of arrow II in FIG. 1; FIG. 2 is a vertical cross-sectional view showing an underfloor structure according to Embodiment 1; It is a perspective view (perspective view of the state where the floor panel was removed) showing the said underfloor structure. FIG. 4 is a vertical cross-sectional view of the underfloor structure (a cross-sectional view taken along line V-V in FIG. 4). It is a horizontal sectional view (VI-VI arrow sectional view of FIG. 5) showing the said underfloor structure. FIG. 4 is a perspective view (perspective view with the reinforcing plate removed) showing the arrangement of the vertical step frame in the underfloor structure. It is a longitudinal cross-sectional view showing the assembly|attachment procedure of the said underfloor structure. It is a perspective view of the reinforcement plate which comprises the said underfloor structure. FIG. 4 is a perspective view of a vertical frame for step forming the underfloor structure; FIG. 4 is a perspective view of an outer case portion of the front seat fixing frame that constitutes the underfloor structure; FIG. 4 is a perspective view of the reinforcement of the frame for fixing the front seat that constitutes the underfloor structure. FIG. 4 is a perspective view of a lower lid portion of the front seat fixing frame that constitutes the underfloor structure; It is a model side view of a small bus. 14. It is an XV arrow enlarged view of FIG.

[Embodiment 1]
A vehicle underfloor structure according to Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 13 . The vehicle underfloor structure according to the present embodiment is an underfloor structure at the front of a small bus (hereinafter referred to as vehicle). Here, front, rear, left, right, and up and down in the drawing correspond to front, rear, left, right, and up and down of the vehicle.

<Overview of Front Underfloor of Vehicle 10>
As shown in FIGS. 1 and 2, the vehicle 10 has a front floor surface 13u (hereinafter referred to as front floor surface 13u) where a driver's seat 12d is located at a relatively high position, and a plurality of passenger seats 12p. A floor surface 13f (to be referred to as a passenger compartment floor surface 13f hereinafter) is formed at a position one step lower than the front floor surface 13u. A stepped portion 13d (see FIG. 2) is formed at the boundary between the front floor surface 13u and the passenger compartment floor surface 13f. Here, a driving mechanism such as an engine of the vehicle 10 is installed below the front floor surface 13u of the vehicle 10. As shown in FIG.

Under the floor of the vehicle 10, as shown in FIG. 2 (enlarged view in the direction of arrow II in FIG. 1), a front floor surface 13u and a floor panel 13 forming a passenger compartment floor surface 13f extend in the vehicle width direction below the floor panel 13. A cross member 20 is provided. Left and right ends of the cross member 20 are connected to side members (not shown) extending in the vehicle front-rear direction on both left and right sides (both sides in the vehicle width direction) under the floor of the vehicle 10 . A plurality of cross members 20 are provided at intervals in the longitudinal direction of the vehicle 10 . Furthermore, on the lower side of the floor panel 13, there are a plurality of seat fixing frames 30m and 30f extending in the longitudinal direction of the vehicle to interconnect the adjacent cross members 20 and to which the leg portions 12k of the seat 12p are fixed. is provided.

As shown in FIG. 2, the cross member 20 provided on the lower side of the floor panel 13 (hereinafter referred to as the upper panel portion 13u) that constitutes the front floor surface 13u is the floor panel 13 (hereinafter referred to as the floor panel 13 that constitutes the passenger compartment floor surface 13f). , the cross member 20 provided on the lower side of the lower panel portion 13f). Here, the cross member 20 provided on the lower side of the upper panel portion 13u of the floor panel 13 is called the first cross member 20, and the cross member 20 provided on the lower side of the lower panel portion 13f of the floor panel 13 is called the first cross member 20. They will be referred to as second to Nth cross members 20 . Since the lower panel portion 13f of the floor panel 13 is horizontal as shown in FIG. 1, the second to Nth cross members 20 are provided at the same height position. Therefore, the second to Nth cross members 20 are connected to each other by a straight main seat fixing frame 30m.

On the other hand, between the first cross member 20 and the second cross member 20 having different height positions, as shown in FIGS. The first cross member 20 and the second cross member 20 are connected by connecting the . Further, the first cross member 20, the vertical step frame 40, and the frontmost seat fixing frame 30f are a reinforcing plate extending over the first cross member 20, the vertical step frame 40, and the frontmost seat fixing frame 30f. 50 are interconnected.

<Regarding the configuration of the cross member 20>
The first to Nth cross members 20 are formed with the same cross-sectional configuration and the same cross-sectional size. As shown in FIGS. 3 to 5 and the like, the cross member 20 is formed in a rectangular groove shape extending in the vehicle width direction by side wall portions 22 and a bottom plate portion 23 on both sides. Flange portions 22f that are horizontally bent outward in the width direction are formed at the upper ends of the side wall portions 22 on both sides (opening sides of the rectangular grooves). The cross member 20 is made of, for example, a steel plate with a thickness of approximately 1.8 mm.

<Regarding the structure of the front seat fixing frame 30f>
The front seat fixing frame 30f has basically the same configuration as the main seat fixing frame 30m, and is set smaller in length than the main seat fixing frame 30m. That is, as shown in FIGS. 2 and 3, the length of the front seat fixing frame 30f is determined from the position of the side wall 22 on the front side of the second cross member 20 to the position of the stepped portion 13d of the floor panel 13. It is set to a value approximately equal to the horizontal dimension up to . As shown in the perspective views of FIGS. 3 and 11 to 13, the front seat fixing frame 30f includes an outer frame portion 32, a reinforcement portion 34 provided inside the outer frame portion 32, and an outer frame portion 32 and a lower lid portion 36 that closes the lower surface of the housing 32 .

As shown in the overall perspective view of FIG. 11, the outer frame portion 32 has a cross section formed by left and right side wall portions 323, a top plate portion 322, and flange-like bent portions 324 formed at the lower ends of the left and right side wall portions 323. It is shaped like a hat. At the front ends of the left and right side wall portions 323 of the outer frame portion 32, rectangular flange portions 323x are formed which are bent outward in the width direction. As shown in FIGS. 5 and 7, the square flange portion 323x of the outer frame portion 32 is joined to the lower end of the trapezoidal vertical flange portion 42 (described later) of the step vertical frame 40 by welding or the like. As shown in FIG. 11, wide flange portions 323y that are bent outward in the width direction are formed at the rear ends of the left and right side wall portions 323 of the outer frame portion 32. As shown in FIG. The wide flange portion 323y of the outer frame portion 32 is joined to the side surface of the front side wall portion 22 of the second cross member 20 by welding or the like, as shown in FIGS.

As shown in FIG. 11, the front portion of the top plate portion 322 of the outer frame portion 32 is recessed in a band-like shape. It becomes the plate receiving part 322u joined by. 11, the rear portion of the top plate portion 322 of the outer frame portion 32 is similarly recessed in a strip shape, and this portion is the flange portion of the second cross member 20, as shown in FIG. 22f serves as a flange receiving portion 322w joined by welding or the like. 11, a bolt insertion hole 322h through which a fixing bolt B (see FIG. 3) for fixing the leg portion 12k of the seat 12p is passed. is formed. Here, the outer frame portion 32 is formed of a steel plate having a thickness of approximately 1.4 mm, for example.

As shown in the overall perspective view of FIG. 12, the reinforcement portion 34 is formed with a substantially gate-shaped cross section from left and right side wall portions 343 and a top plate portion 342 . The left and right side wall portions 343 of the reinforcement portion 34 are aligned with the left and right side wall portions 323 of the outer frame portion 32 from the inside, and the top plate portion 342 of the reinforcement portion 34 is aligned with the top plate portion 322 of the outer frame portion 32 from the inside. adapted from. In the top plate portion 342 of the reinforcement portion 34, a plate receiving portion 342u is formed at a position corresponding to the plate receiving portion 322u of the top plate portion 322 of the outer frame portion 32. A flange receiving portion 342w is formed at a position corresponding to the flange receiving portion 322w. Further, the top plate portion 342 of the reinforcement portion 34 is provided with a female screw hole 342n having a nut N at a position corresponding to the bolt insertion hole 322h of the top plate portion 322 of the outer frame portion 32 . Here, the reinforcement portion 34 is formed of a steel plate having a thickness of approximately 2.0 mm, for example.

As shown in the overall perspective view of FIG. 13 , the lower lid portion 36 is formed with a substantially gate-shaped cross section from left and right side wall portions 363 and a top plate portion 362 . Then, the left and right side wall portions 363 of the lower lid portion 36 are aligned with the left and right side wall portions 343 of the reinforcement portion 34 from the inside, so that the outer frame portion 32 is closed from below as shown in FIG. 5 and the like. become. The top plate portion 362 of the lower lid portion 36 has an insertion hole at a position corresponding to the nut N of the top plate portion 342 of the reinforcement portion 34, through which the nut N and the tip of the fixing bolt B protruding downward from the nut N are passed. 262h is formed. Here, the lower lid portion 36 is formed of a steel plate having a thickness of approximately 1.8 mm, for example.

<Regarding the vertical frame 40 for steps>
As shown in FIGS. 3 and 5, the step vertical frame 40 is arranged below the corner between the upper panel portion 13u and the stepped portion 13d of the floor panel 13, and is located on the rear side of the first cross member 20. It is a frame that connects the side wall portion 22 and the front end of the front seat fixing frame 30f. As shown in the overall perspective view of FIG. 10 , the vertical frame 40 for steps is formed by a left side wall portion 43 , a right side wall portion 44 , and a front wall portion 45 connecting upper front ends of the left and right side wall portions 43 and 44 . It is formed in a groove shape extending in the direction. A trapezoidal vertical flange portion 42 bent outward in the width direction is formed at the rear end positions of the left and right side wall portions 43 and 44, that is, at the opening side of the groove. A square horizontal flange portion 47 that is bent outward in the width direction is formed at the center position of the upper ends of the left and right side wall portions 43 and 44 .

As shown in FIGS. 5 to 7, the front wall portion 45 of the vertical step frame 40 is joined to the outer surface of the rear side wall portion 22 of the first cross member 20 by welding or the like. As shown in FIG. 7, the step vertical frame 40 has a square flange portion 323x formed at the front end of the outer frame portion 32 of the front seat fixing frame 30f at the lower portion of the left and right trapezoidal vertical flange portions 42. is spliced to As a result, the first cross member 20 and the front seat fixing frame 30 f are connected via the vertical step frame 40 . As shown in FIGS. 4 and 5, the portions other than the lower portions of the left and right rectangular horizontal flange portions 47 and the left and right trapezoidal vertical flange portions 42 of the vertical step frame 40 are the first cross members 20, . It is joined by welding or the like to the vertical step frame 40 and the reinforcement plate 50 that straddles the front portion of the front seat fixing frame 30f. The step vertical frame 40 is made of, for example, a steel plate with a thickness of about 1.6 mm.

<Regarding the reinforcing plate 50>
As described above, the reinforcing plate 50 is a plate that spans the front portions of the first cross member 20, the vertical step frame 40, and the frontmost seat fixing frame 30f, and as shown in the overall perspective view of FIG. , the horizontal upper plate portion 52 , the vertical plate portion 53 and the lower end horizontal flange portion 55 form a substantially Z-shaped cross section. As shown in FIG. 5 and the like, the reinforcing plate 50 is configured to fit the upper panel portion 13u, the stepped portion 13d, and the lower panel portion 13f of the floor panel 13 from below. As shown in FIG. 5, the longitudinal width of the horizontal upper plate portion 52 of the reinforcing plate 50 extends from the front flange portion 22f of the first cross member 20 to the trapezoidal vertical flange portion 42 of the vertical step frame 40. is set to be approximately equal to the horizontal dimension of Further, the height dimension of the vertical plate portion 53 of the reinforcing plate 50 is from the upper surface of the flange portion of the first cross member 20 to the plate receiving portion formed at the upper front end of the outer frame portion 32 of the front seat fixing frame 30f. It is set to have a value approximately equal to the height dimension up to 322u.

As shown in FIG. 4 and the like, the vertical plate portion 53 of the reinforcing plate 50 has a bead 53b having an inverted trapezoidal cross section extending downward from the position of the horizontal upper plate portion 52 to the vicinity of the lower portion of the vertical plate portion 53 at the center position. formed. In addition, on the left and right ends of the vertical plate portion 53 of the reinforcing plate 50, bead halves 53w, which are halves of the bead 53b, are formed at the same height position as the bead 53b. 4 and 5, the horizontal upper plate portion 52 of the reinforcing plate 50 is connected to the front and rear flange portions 22f of the first cross member 20 and the left and right rectangular horizontal flange portions 47 of the vertical step frame 40. spliced. Further, both left and right sides of the bead 53b in the vertical plate portion 53 of the reinforcing plate 50 are joined to the left and right trapezoidal vertical flange portions 42 of the vertical step frame 40, as shown in FIG. That is, the opening side of the groove extending in the vertical direction of the vertical frame 40 for the step is closed by the vertical plate portion 53 of the reinforcing plate 50 . Further, as shown in FIG. 4, the lower end horizontal flange portion 55 of the reinforcing plate 50 is joined to the plate receiving portion 322u of the outer frame portion 32 of the front seat fixing frame 30f.

As a result, the first cross member 20, the vertical step frame 40, and the front portion of the frontmost seat fixing frame 30f are connected by the first cross member 20, the vertical step frame 40, and the frontmost seat fixing frame 30f. are firmly connected by a reinforcing plate 50 straddling the front part of the . Here, as shown in FIG. 5 and the like, the first cross member 20 is formed in a rectangular tubular shape extending in the vehicle width direction by covering the upper side with the horizontal upper plate portion 52 of the reinforcing plate 50 . Further, as shown in FIG. 6, the vertical frame 40 for step is formed in a square tubular shape extending in the vertical direction by covering the rear side with the vertical plate portion 53 of the reinforcing plate 50 . Here, since the vertical plate portion 53 of the reinforcing plate 50 is formed with the bead 53b at a position covering the space in the groove of the vertical frame 40 for the step, the vertical plate portion of the vertical frame 40 for the step and the vertical plate portion of the reinforcing plate 50 are formed. The rigidity of the square tubular portion formed by 53 against the vertical load is increased. The reinforcing plate 50 is made of, for example, a steel plate with a thickness of approximately 2.0 mm.

<Assembly Procedure for Front Underfloor of Vehicle 10>
When assembling the front underfloor of the vehicle 10, first, as shown in FIG. They are brought together and joined by welding or the like. Next, the horizontal upper plate portion 52 of the reinforcing plate 50 is aligned with the front and rear flange portions 22f of the first cross member 20 and the left and right square horizontal flange portions 47 of the vertical step frame 40, and joined by welding or the like. . Further, both left and right sides of the bead 53b in the vertical plate portion 53 of the reinforcing plate 50 are joined to the left and right trapezoidal vertical flange portions 42 of the vertical frame 40 for step by welding or the like.

Further, as shown in FIG. 8, the reinforcing plate 50 and the flange portion 22f (see FIG. 5) of the first cross member 20 exposed from the reinforcing plate 50 are covered with the floor panel 13 and joined by welding or the like. be done. Next, the square flange portions 323x at the front end of the outer frame portion 32 of the front seat fixing frame 30f are joined to the lower portions of the left and right trapezoidal vertical flange portions 42 of the step vertical frame 40 by welding or the like. A plate receiving portion 322u formed at the upper front end of the outer frame portion 32 of the front seat fixing frame 30f is joined to the lower end horizontal flange portion 55 of the reinforcing plate 50 by welding or the like.

Next, the wide flange portion 323y at the rear end of the outer frame portion 32 of the front seat fixing frame 30f is welded to the outer surface of the front side wall portion 22 of the second cross member 20, as shown in FIG. etc. A flange receiving portion 322w at the rear end upper portion of the outer frame portion 32 of the front seat fixing frame 30f is joined to the front flange portion 22f of the second cross member 20 by welding or the like. Thus, the connection between the first cross member 20, the vertical step frame 40, the frontmost seat fixing frame 30f and the second cross member 20, and the connection between the reinforcing plate 50 and the floor panel 13 are completed.

Next, as shown in FIG. 3, the exterior material 60 is set on the floor panel 13, and the seat 12p is fixed to the passenger compartment floor surface 13f. For fixing the front seat 12p, the front fixing bolt B provided at the lower portion of the leg portion 12k of the seat 12p is fastened to the nut N of the front seat fixing frame 30f. A fixing bolt (not shown) on the rear side of the leg portion 12k of the seat 12p is fastened to a nut of a reinforcement (not shown) inside the second cross member 20. As shown in FIG. Here, the two-dot chain line in FIG. 3 represents a state in which the seat 12p in the front row is tilted forward due to the collision load when the vehicle 10 has a frontal collision. A black arrow F represents a downward load applied to the frontmost seat fixing frame 30f when the seat 12p is tilted forward.

As described above, the front portion of the front seat fixing frame 30f is connected to the first cross member 20 via the vertical step frame 40. As shown in FIG. The front portion of the front seat fixing frame 30f, the vertical step frame 40, and the first cross member 20 are connected to each other by the front portion of the front seat fixing frame 30f, the vertical step frame 40, and the first cross member 20. They are interconnected by reinforcing plates 50 straddling the members 20 . That is, the first cross member 20, the vertical step frame 40, and the front portion of the frontmost seat fixing frame 30f are reinforced by the reinforcing plate 50 throughout. Therefore, the rigidity of the vertical step frame 40 connecting the first cross member 20 and the second cross member 20 having different height positions and the frontmost seat fixing frame 30f is set to the linear main seat fixing frame 30m. can be increased to the same extent as the stiffness of

As a result, even if a downward load F is applied to the frontmost seat fixing frame 30f when the seat 12p is tilted forward in the event of a frontal collision of the vehicle, the front portion of the frontmost seat fixing frame 30f and the step vertical frame are prevented from moving forward. 40 becomes difficult to deform, and the load F can be effectively received by the first cross member 20. - 特許庁Further, when the seat 12p is tilted forward, the front surface of the leg 12k of the seat 12p can be supported by the stepped portion 13d of the floor panel 13 whose rigidity is improved by the vertical step frame 40 and the reinforcing plate 50. FIG. As a result, it is possible to prevent the seat 12p from collapsing forward when the vehicle 10 has a frontal collision. That is, the fixing stability of the seat 12p at the time of vehicle collision is improved.

<Correspondence between terms used in the present embodiment and terms in the present invention>
The cross member 20 in this embodiment corresponds to the underfloor frame of the present invention. Further, the frontmost seat fixing frame 30f corresponds to the predetermined seat fixing frame of the present invention, and the main seat fixing frame 30m corresponds to the seat fixing frame of the present invention. Furthermore, the reinforcing plate 50 corresponds to the reinforcing member of the present invention.

<Advantages of the vehicle underfloor structure according to the present embodiment>
According to the underfloor structure of the vehicle according to this embodiment, the front portion of the frontmost seat fixing frame 30f (predetermined seat fixing frame) is connected to the first cross member 20 (underfloor frame) through the vertical step frame 40. connected to The front portion of the front seat fixing frame 30f, the vertical step frame 40, and the first cross member 20 are connected to each other by the front portion of the front seat fixing frame 30f, the vertical step frame 40, and the first cross member 20. They are connected to each other by reinforcing plates 50 (reinforcing members) straddling the members 20 . Therefore, the rigidity of the vertical step frame 40 connecting the first cross member 20 and the second cross member 20 having different height positions and the frontmost seat fixing frame 30f is set to the linear main seat fixing frame 30m. can be increased to the same extent as the stiffness of

The vertical frame 40 for steps and the reinforcing plate 50 are joined to each other to form a vertically oriented rectangular tubular hollow closed cross section. Therefore, the rigidity of the joined body between the vertical step frame 40 and the reinforcing plate 50 is increased. Further, the reinforcing plate 50 is formed with a bead 53b extending in the vertical direction at a position covering the space in the groove of the vertical frame 40 for step. That is, the bead 53b increases the rigidity in the vertical direction of the joined body of the vertical step frame 40 and the reinforcing plate 50. As shown in FIG.

<Change example>
Here, the present invention is not limited to the above embodiments, and modifications can be made without departing from the gist of the present invention. For example, in this embodiment, after the reinforcing plate 50 is joined to the first cross member 20, the vertical step frame 40, and the front portion of the frontmost seat fixing frame 30f, the reinforcing plate 50 and the like are attached to the floor panel 13. An example of covering and joining with is shown. However, after the first cross member 20, the vertical step frame 40, and the front portion of the frontmost seat fixing frame 30f are covered and joined together with the floor panel 13, the floor panel 13 is covered with the reinforcing plate 50, A configuration in which the reinforcing plate 50 is joined to the first cross member 20, the vertical step frame 40, and the front portion of the front seat fixing frame 30f is also possible. In this embodiment, the front wall portion 45 of the vertical frame 40 for step is joined to the outer surface of the side wall portion 22 of the first cross member 20, and the left and right trapezoidal vertical flange portions 42 are connected to the vertical plates of the reinforcing plate 50. An example of bonding to the portion 53 is shown. However, by changing the vertical dimension of the front wall portion 45 of the vertical frame 40 for steps and the left and right trapezoidal vertical flange portions 42 , the left and right trapezoidal vertical flange portions 42 are moved to the side wall portions 22 of the first cross member 20 . It is also possible to join the front wall portion 45 to the vertical plate portion 53 of the reinforcing plate 50 by joining to the outer surface.

10...Vehicle 12p...Seat 12k...Leg 13...Floor panel 13f...Room floor (lower panel)
13u ... Front floor (upper panel)
13d: stepped portion 20: cross member (underfloor frame)
22f... Flange portion 30m... Main seat fixing frame (seat fixing frame)
30f: frame for fixing frontmost seat (predetermined frame for fixing seat)
40: Vertical frame for step 50: Reinforcing plate (reinforcing member)

Claims (6)

A plurality of underfloor frames provided in parallel at intervals under a floor panel of a vehicle, and extending in a direction crossing the underfloor frame under the floor panel to connect the underfloor frames to each other. An underfloor structure for a vehicle comprising a plurality of seat fixing frames to which leg portions of seats are fixed,
a second underfloor frame adjacent to the first underfloor frame is positioned lower than the first underfloor frame;
The floor panel is provided with an upper panel portion covering the first underfloor frame, a lower panel portion covering the second underfloor frame, and a stepped portion between the upper panel portion and the lower panel portion. cage,
A predetermined seat fixing frame connected to the second underfloor frame is provided on the lower side of the lower panel portion of the floor panel,
Under the corner between the upper panel portion of the floor panel and the stepped portion, a vertical step frame is provided for connecting the first underfloor frame and the end portion of the predetermined seat fixing frame. ,
Further, the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame are reinforcing members spanning the first underfloor frame, the vertical step frame, and the predetermined seat fixing frame. vehicle underfloor structure interconnected by The vehicle underfloor structure according to claim 1,
The underfloor frame is a frame extending in the vehicle width direction,
The seat fixing frame is a frame extending in the longitudinal direction of the vehicle,
The underfloor structure of a vehicle, wherein the predetermined seat fixing frame has a front end connected to the step vertical frame and a rear end connected to the second underfloor frame. The vehicle underfloor structure according to claim 1 or claim 2,
The underfloor frame is formed in a groove shape, and flange portions are formed on both sides of the opening of the groove,
The underfloor structure of a vehicle, wherein the reinforcing member is a plate-shaped molding, and is joined to the flange portions on both sides of the first underfloor frame while being superimposed on the flange portions. The vehicle underfloor structure according to any one of claims 1 to 3,
In the vehicle underfloor structure, the step vertical frame and the reinforcing member are joined together to form a hollow closed cross section. The vehicle underfloor structure according to claim 4,
The vertical frame for steps is formed in a groove shape extending in the vertical direction, and flange portions are formed on both sides of the opening of the groove,
The underfloor structure of a vehicle, wherein the reinforcing member is joined to the flange portions on both sides of the vertical frame for step while being superimposed on the flange portions. The vehicle underfloor structure according to claim 5,
The underfloor structure of a vehicle, wherein a bead extending in the vertical direction is formed in the reinforcing member at a position covering the space in the groove in the vertical frame for step.

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