JP2010228731A - Underfloor structure for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underfloor structure for a vehicle for more certainly suppressing deformation of a floor tunnel portion by transmitting impact load from a tunnel side member at a side receiving the impact load to the tunnel side member at an opposite side when the impact load is received from a side, reducing manufacturing cost and enhancing rigidity of a vehicle body. <P>SOLUTION: The floor tunnel 2 is formed on a floor panel 1 of the vehicle body, a pair of left and right tunnel side members 4 is independently arranged at both left and right sides of the floor tunnel 2 along the floor tunnel 2, and both left and right end parts 50A, 50B of a brace 50 for connecting the pair of left and right tunnel side members 4 are independently fixed to a lower surface 4K of a rear end part of the pair of left and right tunnel side members 4. The brace 50 is constituted to a closed cross section structure by joining an upper member 6 to a lower member 7, and end parts 6A, 6B in a left/right direction W of the upper member 6 are opposed to a side surface 4S of the tunnel side member 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention
A floor tunnel is formed on the floor panel of the car body,
A pair of left and right tunnel side members are arranged separately on the left and right sides of the floor tunnel along the floor tunnel,
The present invention relates to a vehicle underfloor structure in which left and right ends of braces connecting the pair of left and right tunnel side members are respectively fixed to lower surfaces of rear end portions of the pair of left and right tunnel side members.

  A floor tunnel for arranging an exhaust pipe and a propeller shaft is formed on the floor panel of the vehicle body. This floor tunnel swells to the vehicle interior side (upward), and the floor tunnel part is easily deformed when an impact load is applied from the side in order to reduce the rigidity of the vehicle body with the floor panel divided into left and right. . As a countermeasure, the left and right ends of the braces that connect the pair of left and right tunnel side members are separately attached to the lower surfaces of the rear ends of the pair of left and right tunnel side members to improve the rigidity of the vehicle body.

Conventionally, in the above-mentioned underfloor structure, the brace is composed of a single metal plate or cast product, and the left and right ends of the metal plate or cast product are attached to the lower surfaces of the rear end portions of the pair of left and right tunnel side members with mounting bolts. It was tightened and fixed.
However, when an impact load is applied from the side, the mounting bolt cannot withstand the load, and it is difficult to effectively transmit the impact load to the brace. Further, since the brace is composed of a single metal plate, the brace is weak against torsional deformation of the vehicle body, and the rigidity of the vehicle body is low. When the brace is made of a cast product, the production cost is high.

As disclosed in Patent Document 1, a pair of upper and lower metal plates are welded and joined to the end of the pipe material in the longitudinal direction (the left-right direction of the vehicle) and protruded from the end of the pipe material to the left and right outer sides, Arrange the left and right outer end faces of the upper metal plate closer to the left and right center of the vehicle than the left and right outer end faces of the lower metal plate, and use the end face of the upper metal plate as the side surface of the tunnel side member. There was a technology to oppose.
Thus, when receiving an impact load from the side, the side surface of the tunnel side member is received by the left and right outer end surfaces of the upper metal plate, and the impact load is passed through the pipe material to the side surface of the opposite tunnel side member. It is reported to suppress the deformation of the floor tunnel part.

JP 2008-184125 A

According to the structure of the above-mentioned conventional Patent Document 1, there is a large difference in strength between the pipe material and the joint between the pipe material and the upper and lower metal plates, and the metal plate is deformed when subjected to an impact load from the side. There was a fear.
An object of the present invention is to more reliably suppress the deformation of the floor tunnel portion by transmitting the impact load when receiving an impact load from the side to the tunnel side member on the opposite side from the tunnel side member on the side receiving the impact load. Therefore, the present invention is to provide a vehicle underfloor structure capable of reducing the manufacturing cost and improving the rigidity of the vehicle body.

The feature of the present invention is that
A floor tunnel is formed on the floor panel of the car body,
A pair of left and right tunnel side members are arranged separately on the left and right sides of the floor tunnel along the floor tunnel,
A vehicle underfloor structure in which left and right ends of braces connecting the pair of left and right tunnel side members are separately fixed to the lower surfaces of the rear ends of the pair of left and right tunnel side members,
The brace is configured in a closed cross-sectional structure by joining the upper member and the lower member,
The end of the upper member in the left-right direction is opposed to the side surface of the tunnel side member. (Claim 1)

Since the brace has a closed cross-sectional structure formed by joining the upper member and the lower member, the brace can be formed into a large closed cross-sectional structure with a high rigidity, and the strength is uniform over the entire length of the brace. It can be configured, and the brace can be prevented from being deformed when subjected to an impact load from the side, and the rigidity of the vehicle body can be improved.
And since the end in the left-right direction of the upper member faces the side surface of the tunnel side member, the side surface of the tunnel side member is received by the end in the left-right direction of the upper member when receiving an impact load from the side. It is possible to suppress the deformation of the floor tunnel portion by transmitting the load to the side surface of the opposite tunnel side member.
Therefore, in a structure in which the left and right ends of the brace are fixed to the lower surfaces of the rear ends of the pair of left and right tunnel side members by mounting bolts, the impact load is transferred to the opposite tunnel side without increasing the number of mounting bolts. Can be communicated to the side of the member.
Further, the manufacturing cost can be reduced as compared with the case where the brace is formed of a cast product. (Claim 1)

In the present invention,
If the height dimension of the left and right end portions of the upper member is higher than the height dimension of the middle portion of the upper member, the left and right ends of the upper member facing the side surface of the tunnel side member The portion can be enlarged in the vertical direction, and the impact load from the side surface of the tunnel side member can be reliably received, and can be reliably transmitted to the side surface of the opposite tunnel side member.
Further, the left and right intermediate portion of the brace can be set low, and interference with the exhaust pipe and the propeller shaft that are passed through the floor tunnel can be avoided, so that the layout of the exhaust pipe and the propeller shaft can be afforded. (Claim 2)

In the present invention,
Between both ends of the upper member in the vehicle front-rear direction, a bead bulging upward is formed along the left-right direction,
When the bead is formed in an arc shape that is located on the upper side toward the end in the left-right direction,
The rigidity of the upper member can be improved, the shape can be optimized with respect to the torsional rigidity of the brace, and the torsional rigidity of the brace and the vehicle body can be improved. (Claim 3)

In the present invention,
The bead of the upper member is formed over the entire length in the left-right direction of the upper member, and if the end surface of the bead in the left-right direction faces the side surface of the tunnel side member, the rigidity of the upper member can be further improved. In addition, the torsional rigidity of the brace can be optimized, and the torsional rigidity of the brace and the vehicle body can be further improved. (Claim 4)

In the present invention,
A plurality of beads of the upper member are formed,
Between both ends of the vehicle front-rear direction of the lower member, a plurality of beads bulging downward are formed along the left-right direction,
When each row of beads of the upper member and each row of beads of the lower member are located at the same position in the vehicle front-rear direction, the rigidity of the upper member and the lower member can be further improved, The shape can be optimized with respect to the torsional rigidity of the brace, and the torsional rigidity of the brace and the vehicle body can be further improved.
In the structure in which the left and right ends of the brace are fixed to the lower surface of the rear end portion of the tunnel side member with mounting bolts, the head of the mounting bolt can be protected from flying stones or the like by the beads of the lower member. (Claim 5)

In the present invention,
The left and right end of the lower member protrudes to the left and right outer sides than the left and right end of the upper member,
A reinforcement is superimposed on the left and right ends of the lower member from above, and the ends of the reinforcement on the left and right center side of the vehicle are the left and right ends of the upper member and the left and right direction of the lower member. And is welded and joined to the end of
When the left and right end portions of the lower member and the left and right outer end portions of the reinforcement are fixed to the lower surface of the rear end portion of the tunnel side member, the following effects can be obtained. (Claim 6)

By providing the reinforcement, it is possible to improve the rigidity of the brace attachment portion with respect to the lower surface of the rear end portion of the tunnel side member. Also, since the end of the reinforcement on the left and right center side of the vehicle is sandwiched and welded between the left and right ends of the upper member and the left and right ends of the lower member, the reinforcement and the lower member Peeling can be prevented and a strong brace can be formed, and the impact load received by the reinforcement can be efficiently transmitted to the upper member and the lower member.
Since the reinforcement is provided only at the left and right ends of the brace and not at the middle in the left and right direction, the volume of the relatively thick reinforcement can be reduced to reduce the weight of the brace. it can. (Claim 6)

In the present invention,
The outer peripheral portion of the joined body composed of the reinforcement and the upper member is formed along the outer peripheral portion of the lower member and protrudes outward of the outer peripheral portion of the lower member,
If a flange that is bent downward is formed over the entire circumference or substantially the entire circumference on the outer peripheral portion of the joined body, the rigidity of the joined body including the reinforcement and the upper member can be improved. In addition, in the structure where the left and right ends of the brace are fixed to the lower surface of the rear end of the tunnel side member with mounting bolts, the peripheral edge surface (small edge) of the lower member and the head of the mounting bolt are protected from stepping stones by the flange. can do. (Claim 7)

According to the present invention,
When the impact load is received from the side, the impact load is transmitted from the tunnel side member on the side receiving the impact load to the tunnel side member on the opposite side, so that the deformation of the floor tunnel part can be suppressed more reliably, and the production cost It is possible to provide a vehicle underfloor structure that can reduce the cost of the vehicle and can improve the rigidity of the vehicle body.

Perspective view of brace seen from diagonally above (A) Perspective view of brace seen from diagonally below (b) Side view of brace CC sectional view of FIG. DD sectional view of FIG. AA sectional view of FIG. BB sectional view of FIG. Bottom view of vehicle floor tunnel and floor panel

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 7 and 3, a floor tunnel 2 along the vehicle longitudinal direction J is formed at the left and right center portion of the floor panel 1 of the body of the automobile. The floor tunnel 2 is formed by bulging upward the left and right central portions of the floor panel 1, and a propeller shaft and an exhaust pipe 3 are passed through the floor tunnel 2. In FIG. 7, symbol Fr is the vehicle front side, and Rr is the vehicle rear side.

  A pair of left and right tunnel side members 4 are arranged separately along the floor tunnel 2 on both the left and right sides of the floor tunnel 2. The left and right ends of the floor panel 1 are attached to side sills, and a pair of left and right side members of the vehicle body frame are attached to the lower surface of the floor panel 1 between the side sill and the tunnel side member 4.

  The tunnel side member 4 is formed in a hat shape with an open upper cross section, and a pair of flanges 4F on the upper side of the tunnel side member 4 are welded to the lower surface of the floor panel 1, and the cross section closed by the tunnel side member 4 and the floor panel 1 Is forming. Further, a plurality of braces 50 and 51 arranged at intervals in the vehicle front-rear direction J are installed on the lower surfaces of the pair of left and right tunnel side members 4 to connect the pair of left and right tunnel side members 4. As a result, the strength of the floor panel 1 around the floor tunnel 2 is increased.

  The floor panel 1 is bent upward and behind the brace 50 on the most rear side Rr to form a vertical wall portion 11, and a floor tunnel 2 passes through the vertical wall portion 11 to form a notch 12. . The floor panel 1 extends rearward from the top of the vertical wall portion 11, and a space for storing a fuel tank, a rear suspension, and the like is formed below the floor panel 1.

  The brace 50 on the most rear side Rr is disposed in the sudden change portion of the shape of the floor panel 1 as described above, and the left and right of the notch 12 of the vertical wall portion 11 are connected to effectively improve the rigidity of the vehicle body. ing. A cross member extending in the left-right direction W (vehicle width direction) of the vehicle is disposed at the upper end corner of the vertical wall portion 11.

The pair of left and right side members of the vehicle body frame has a left-right space extending on the vehicle rear side Rr, and a suspension arm is attached to the lower surface of the side member behind the vertical wall portion 11. That is, the suspension arm is attached in the vicinity of the left and right end portions of the vertical wall portion 11.
Next, the structure of the brace 50 on the most rear side Rr of the vehicle (hereinafter simply referred to as “brace 50”) will be described.

[Structure of brace 50]
As shown in FIGS. 1, 2 (a), 2 (b), 5, and 6, the brace 50 joins the upper member 6 and the lower member 7 made of a long metal plate in the lateral direction W of the vehicle. The left and right end portions 50A and 50B of the brace 50 are separately fixed to the lower surfaces 4K of the rear end portions of the pair of left and right tunnel side members 4 as shown in FIG. 6 end portions 6A, 6B in the left-right direction W face the side surface 4S of the tunnel side member 4 from the left-right center side W1 of the vehicle.

  The upper member 6 is formed in a rectangular shape in plan view, and a first bead B1 having an arcuate vertical section that bulges upward is provided in the left-right direction W between both ends 6D and 6E of the upper member 6 in the vehicle longitudinal direction J. Are formed along. The first bead B1 is formed in an arc shape that is located on the upper side toward the ends 6A and 6B in the left-right direction W. The height dimension 6T1 (see FIG. 3) of the end portions 6A and 6B in the left-right direction W of the upper member 6 is formed to be higher than the height dimension 6T2 of the middle portion of the upper member 6 in the left-right direction.

A plurality of the first beads B1 are formed over the entire length of the upper member 6 in the left-right direction W, and the end of the first bead B1 in the left-right direction W is opened and positioned below the flange 4F at the upper end of the tunnel side member 4. While facing the lower surface of the flange 4F close from below (see FIG. 3), the end face B1a of the first bead B1 in the left-right direction W (the end face in the longitudinal direction of the first bead B1) faces the side face 4S of the tunnel side member 4. Closely facing each other. Then, the upper corner of the end portion of the first bead B1 in the left-right direction W is disposed so as to face at least the upper half position of the side surface 4S of the tunnel side member 4, and the flange 4F and the side surface 4S of the tunnel side member 4 are disposed. It is placed close to the corner. As a result, force is reliably transmitted between the tunnel side member 4 and the upper member 6.

The lower member 7 is formed in a trapezoidal shape in which both end portions 7A and 7B in the left-right direction W are wider toward the left and right outer side W2 of the vehicle, and an intermediate portion 7C between both end portions 7A and 7B is a short side of the trapezoid. It is formed in a rectangular shape having the same width as the length of.
In addition, a plurality of second beads B2 having a trapezoidal cross section that bulges downward are formed along the left-right direction W between both end portions 7D, 7E of the lower member 7 in the vehicle front-rear direction J. Each row of the first bead B1 and each row of the second bead B2 of the lower member 7 are located at the same position in the vehicle front-rear direction J (see FIG. 2B).
The second bead B2 is formed over the entire length of the lower member 7 in the left-right direction W, and the end of the second bead B2 in the left-right direction W is open. The second bead B2 includes a plurality of drain holes H. Since the end of the second bead B2 in the left-right direction W is open, the water that has entered the brace 50 is easily discharged. In addition, since the second bead B2 is disposed so as to pass between a plurality of bolt insertion holes S to be described later in the left-right direction, the head of the mounting bolt 9 is moved from the stepping stone by the second bead B2 protruding downward. Can be protected.

[Brace 50 mounting structure]
Both end portions 7A, 7B in the left-right direction W of the lower member 7 protrude to the left and right outer sides W2 separately from the both end portions 6A, 6B in the left-right direction W of the upper member 6, respectively. A pair of left and right reinforcements 8 are overlapped on both ends 7A and 7B from above.
The reinforcement 8 is formed in a trapezoidal shape in which the end 8B on the left and right outer side W2 of the vehicle is wider than the end 8A on the left and right center side W1 of the vehicle, and the end of the reinforcement 8 on the left and right center side W1 of the vehicle. 8A is sandwiched and welded between the end 6A (or 6B, the same below) of the upper member 6 in the left-right direction and the end 7A (or 7B, same below) of the lower member 7 in the left-right direction W.

  That is, as shown in FIGS. 1, 2, and 6, end portions 6 </ b> A <b> 1 (6 </ b> B <b> 1) on both sides of the first bead B <b> 1 in the vehicle front-rear direction J among the end portions 6 </ b> A (6 </ b> B) of the upper member 6 in the left-right direction W. And end portions on both sides of the second bead B2 in the vehicle longitudinal direction J of the end portion 8A of the reinforcement 8 on the left and right center side W1 of the vehicle and the end portion 7A (7B) of the lower member 7 in the left and right direction W. 7A1 (7B1) is integrally welded by spot welding.

Thereby, peeling of the reinforcement 8 and the lower side member 7 can be prevented, and it can comprise in the brace 50 with intensity | strength. Further, the force received by the reinforcement 8 can be efficiently transmitted to the upper member 6 and the lower member 7.
Of the end portions 7A (7B) in the left-right direction W of the lower member 7, the end portions 7A1 (7B1) on both sides of the second bead B2 in the vehicle front-rear direction J are more vehicles than the end portions 7A1 (7B1). The intermediate member 7C of the lower member 7 of the left and right center side W1 is positioned one step below via a step 13.

  Since the reinforcement 8 is provided only at the end portions 50A and 50B in the left-right direction W of the brace 50 and not at the middle portion, the volume of the relatively thick reinforcement 8 can be reduced to achieve weight reduction. Can do.

  As shown in FIGS. 1, 2 and 4, an end portion 7A (7B) in the left-right direction W of the lower member 7 and an end portion 8B of the reinforcement 8 on the left-right outer side W2 of the vehicle overlapped therewith In addition, a plurality of bolt insertion holes S are formed that are spaced apart in the vehicle longitudinal direction J. A mounting bolt 9 is inserted into the bolt insertion hole S, and the mounting bolt 9 is screwed into a nut N mounted inside the tunnel side member 4 so that the end 7A (7B) of the lower member 7 in the left-right direction W And the end 8B of the reinforcement 8 on the left and right outer side W2 of the vehicle are bolted to the lower surface 4K of the rear end of the tunnel side member 4. The end portion 7A (7B) in the left-right direction W of the lower member 7 and the end portion 8A of the brace 50 in the left-right direction 50A (the end portion 8A of the reinforcement 8 on the left-right outer side W2 of the vehicle) 50B).

  In this way, the end 7A (7B) in the left-right direction W of the lower member 7 and the end 8B of the reinforcement 8 on the left-right outer side W2 of the vehicle are attached to the lower surface 4K of the rear end of the tunnel side member 4. Therefore, the end of the upper member 6 that faces the side surface 4S of the tunnel side member 4 can be formed by the edge of the upper member 6, and the configuration and formation of the upper member 6 are facilitated. .

  Ends 7A and 7B in the left-right direction W of the lower member 7 and ends 8B of the reinforcement 8 on the left and right outer side W2 of the vehicle are formed in a trapezoidal shape, and the vehicle is more than the intermediate portion 7C of the lower member 7 Since the length in the front-rear direction J is set to be long, the intervals in the vehicle front-rear direction J of the plurality of bolt insertion holes S can be set wide. As a result, it is possible to improve the mounting rigidity against the force in the torsional direction without increasing the number of mounting bolts 9 (tightening bolts).

The outer peripheral portion 10G of the joined body 10 composed of the reinforcement 8 and the upper member 6 is formed along the outer peripheral portion 7G of the lower member 7 and protrudes outward from the outer peripheral portion 7G of the lower member 7. A flange 10 </ b> F that is bent downward is formed on the outer peripheral portion 10 </ b> G of the joined body 10 over substantially the entire circumference (or the entire circumference may be sufficient). Thereby, the rigidity of the joined body 10 can be improved, and the peripheral end face (small edge) of the lower member and the mounting bolt can be protected.

As described above, the height dimension 6T1 of the end portions 6A, 6B in the left-right direction W of the upper member 6 is formed to be higher than the height dimension 6T2 of the middle portion in the left-right direction of the upper member 6, and the left-right center side of the vehicle Since the end portion of the reinforcement 8 of W1 is sandwiched between the end portion 6A (6B) in the left-right direction W of the upper member 6 and the end portion 7A (7B) in the left-right direction W of the lower member 7, it is welded. The end portion of the reinforcement 8 on the left and right center side W1 of the vehicle is connected to the end portion 6A (6B) in the left-right direction W of the upper member 6 having a relatively large effective cross-sectional area, and has high rigidity. Connection is possible.

DESCRIPTION OF SYMBOLS 1 Floor panel 2 Floor tunnel 4 Tunnel side member 4K The lower surface 4S of the rear end part of a tunnel side member Side surface 6 of a tunnel side member Upper member 6A, 6B The edge part 6T1 of the upper member of the left-right direction Height dimension 6T2 Height dimension 6D, 6E of the middle part of the upper member in the left-right direction Both ends 7 of the upper member in the vehicle front-rear direction 7 Lower members 7A, 7B Left and right ends 7D, 7E of the lower member Both ends 7G in the vehicle longitudinal direction Outer peripheral portion 8 of the lower member Reinforce 8A End portion 8B of the reinforcement on the left and right center side of the vehicle End 10 on the left and right outer sides of the reinforcement 10 Joint 10F Flange 10G 50A, 50B Left and right ends of the brace B1 bead (bead of the upper member, first bead)
B1a Bead end face in the left-right direction B2 Bead (bead of lower member, second bead)
J Vehicle front-rear direction W Left-right direction W1 Vehicle left-right center side W2 Left-right outer side

Claims (7)

A floor tunnel is formed on the floor panel of the car body,
A pair of left and right tunnel side members are arranged separately on the left and right sides of the floor tunnel along the floor tunnel,
A vehicle underfloor structure in which left and right ends of braces connecting the pair of left and right tunnel side members are separately fixed to the lower surfaces of the rear ends of the pair of left and right tunnel side members,
The brace is configured in a closed cross-sectional structure by joining the upper member and the lower member,
A vehicle underfloor structure in which a lateral end portion of the upper member faces a side surface of the tunnel side member.   The underfloor structure for a vehicle according to claim 1, wherein a height dimension of a left and right end portion of the upper member is formed higher than a height dimension of a middle portion of the upper member in the left and right direction. Between both ends of the upper member in the vehicle front-rear direction, a bead bulging upward is formed along the left-right direction,
The vehicle underfloor structure according to claim 2, wherein the bead is formed in an arc shape that is located on an upper side toward an end portion in a left-right direction.   The vehicle underfloor structure according to claim 3, wherein the bead of the upper member is formed over the entire length of the upper member in the left-right direction, and the end surface in the left-right direction of the bead faces the side surface of the tunnel side member. A plurality of beads of the upper member are formed,
Between both ends of the vehicle front-rear direction of the lower member, a plurality of beads bulging downward are formed along the left-right direction,
The vehicle underfloor structure according to claim 3 or 4, wherein each row of beads of the upper member and each row of beads of the lower member are located at the same position in the vehicle front-rear direction. The left and right end of the lower member protrudes to the left and right outer sides than the left and right end of the upper member,
A reinforcement is superimposed on the left and right ends of the lower member from above, and the ends of the reinforcement on the left and right center side of the vehicle are the left and right ends of the upper member and the left and right direction of the lower member. And is welded and joined to the end of
The left and right end portions of the lower member and the left and right outer end portions of the reinforcement are fixed to the lower surface of the rear end portion of the tunnel side member. The vehicle underfloor structure described. The outer peripheral portion of the joined body composed of the reinforcement and the upper member is formed along the outer peripheral portion of the lower member and protrudes outward of the outer peripheral portion of the lower member,
The underfloor structure for a vehicle according to claim 6, wherein a flange that is bent downward is formed on an entire periphery or substantially the entire periphery of the outer peripheral portion of the joined body.

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