JP2008195372A - Reinforcing structure of vehicle body lower part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To strengthen torsion rigidity of a vehicle body lower part, and exert a good ride quality performance. <P>SOLUTION: Lockers 3 provided along both of right and left edges of a compartment floor F are connected to a vehicle width central part of a cross member 2 bridged in a vehicle width direction between right and left side members 1 extending from the compartment floor F with a pair of approximately V-shaped right and left braces 5 bent into a gradual obtuse angle and opened upward at a longitudinal intermediate position. A damper (shock-absorbing member) 6 connecting, in the vertical direction, a bent part 51 at the intermediate part in the longitudinal direction of the right and left braces 5 and a vehicle body side portion 1b thereabove is bridged, and a proper spring performance is exerted by a combination of the braces 5 and the damper 6, so as to restrain deformation toward a fore-and-aft reverse phase of the right and left positions on the compartment floor F side, strengthen torsion rigidity of the vehicle body, and realize good ride quality. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reinforcement structure for a lower part of a vehicle body, and more particularly to a reinforcement structure for enhancing torsional rigidity of a vehicle body.

  An automobile, particularly an open car without a fixed roof part, has a lower torsional rigidity of the vehicle body than an ordinary passenger car with a roof part. For this reason, in an open car, the torsional resonance frequency of the vehicle body is remarkably lowered, and there is a problem that the vehicle body is liable to torsionally vibrate due to input from the suspension or the like when the vehicle is traveling. Therefore, in the conventional open car, the torsional vibration of the vehicle body is reduced by connecting the passenger compartment floor side and the extension side of the front side member extending forward from the passenger compartment floor with a brace. (For example, refer to Patent Document 1).

  FIG. 8 shows a conventional representative reinforcing structure of this type. The left and right front side members 1 and 1 extending in parallel with the vehicle longitudinal direction are joined at the rear end of the rear side along the lower surface of the passenger compartment floor F. The first half extends from the front edge of the vehicle compartment floor F to the front engine room side. A cross member (suspension cross member) 2 is installed in the vehicle width direction on the first half of the front side members 1 and 1. Lockers 3 and 3 are installed along the left and right side edges of the passenger compartment floor F, and the floor cross member 4 extending between the left and right side lockers 3 and 3 in the vehicle width direction is provided on the upper surface of the passenger compartment floor F. The front side members 1 and 1 are provided so as to intersect with the base end portions.

And the base end part of the left and right front side members 1 and 1 on the lower surface side of the passenger compartment floor F and the vehicle width direction center part of the cross member 2 of the extending part are made of a pair of left and right metal bars or pipes. These braces 5 and 5 are connected in a substantially V shape in plan view. By providing these left and right braces 5 and 5, it is possible to prevent the torsional resonance frequency of the vehicle body from being significantly lowered, and torsional vibration of the vehicle body due to input from the front suspension during vehicle travel.
Japanese Patent Laid-Open No. 5-116648

  By the way, an open car is produced on the basis of a normal passenger car having a roof part, and a lower body structure common to that of a normal passenger car is applied. Therefore, the left and right braces 5, 5 are relatively small-diameter metal bars or Pipe material is used. However, braces 5 and 5 made of small-diameter metal bars or pipes do not always have a sufficient effect of strengthening the torsional rigidity of the vehicle body, and the vehicle body may be twisted and vibrated depending on conditions such as speed and road surface conditions during vehicle travel. is there. In addition, in the braces 5 and 5 made of straight bars and pipes, the input from the front suspension is transmitted to the passenger compartment floor as it is, and the rider feels stuffy when traveling and the ride comfort is not very good. . Accordingly, an object of the present invention is to provide a reinforcing structure for a lower part of a vehicle body that can surely reduce torsional vibration of the vehicle body and exhibit good riding comfort performance.

The present invention relates to a pair of left and right braces between the left and right side positions on the lower surface side of the passenger compartment floor and the center portion in the vehicle width direction of the cross member extending between the extension portions of the left and right side members extending from the passenger compartment floor. In the reinforcing structure of the lower part of the vehicle body connected in a substantially V shape in plan view, each brace is formed in a substantially square shape that is bent in an obtuse angle at the middle in the longitudinal direction and opens upward. The base end of the brace is connected to a rocker installed along the left and right side edges of the passenger compartment floor, the tip is connected to the center of the cross member, the middle bent part of the brace, and the upper part of the bent part The lower part of the vehicle body is connected in the vertical direction by a buffer member (claim 1).
A cross member central portion that is displaced to the left and right in the vehicle width direction by a suspension input or the like when the vehicle travels by connecting the left and right side positions on the lower side of the passenger compartment floor with braces to the vehicle width direction central portion of the cross member on the side member side. The brace is formed in an almost square shape that opens upward while suppressing vibration of the brace, so that the brace is deformable, and the bending part and the vehicle body are connected vertically by the bending part and the body displacement due to the deformation of the brace. It is possible to suppress the torsional vibration of the vehicle body by these spring performances and to suppress the torsional vibration of the vehicle body, and to achieve an excellent ride comfort.

The brace connects the vicinity of the front ends of the left and right rockers to the center part in the vehicle width direction of the front suspension cross member that extends between the extension parts extending forward from the passenger compartment floor of the left and right front side members. (Claim 2).
The brace connects the vicinity of the rear ends of the left and right rockers and the center part in the vehicle width direction of the rear suspension cross member that is extended between the extension portions extending rearward from the passenger compartment floor of the left and right rear side members. (Claim 3).
The present invention can be applied to the reinforcement of the front side and the rear side of the vehicle body.

In the brace, the bending angle of the bent portion is set in the range of 150 to 170 degrees.
The cushioning member can be operated efficiently by replacing the change in the distance between the connecting portions at both ends of the brace due to the deformation of the left and right reverse phases of the left and right sides of the passenger compartment floor with a large displacement of the vertical stroke of the bent portion of the brace. .

The cushioning member is mounted between the middle bent part of the brace and the lower part of the vehicle body in an up-down direction and in an inclined manner, and the bent part and the lower part of the vehicle body are connected in an inclined posture opposite to the inclined posture of the buffer member. An auxiliary member connected in the vertical direction and in an inclined shape is provided.
Since the buffer member is arranged in the vertical direction and in an inclined shape, a space for installing the buffer member can be secured, and a buffer member having a relatively large size and good buffer performance can be used.
The vertical displacement of the bent part of the brace is restricted by the auxiliary member that connects the bent part and the lower part of the vehicle body in an inclined manner so as to rotate around the fixed part of the auxiliary member to the lower surface of the vehicle body. Suppresses efficiently.

The buffer member is provided so as to connect the extending portion of the side member extending from the passenger compartment floor and the intermediate bent portion of the brace in an inclined posture in the vertical direction,
The auxiliary member is provided so as to connect the base end portion of the side member along the lower surface of the passenger compartment floor and the intermediate bent portion of the brace in an inclined posture in the vertical direction.
There is a space below the extension portion of the side member extending from the passenger compartment floor, which is suitable for installing a buffer member.

An opening angle between the buffer member and the auxiliary member is obtusely formed (Claim 7).
The buffer member can efficiently suppress the displacement of the bent portion of the brace that is restricted by the auxiliary member and is displaced along an arc centering around the vicinity of the fixed portion of the auxiliary member to the lower surface of the vehicle body.

The buffer member is constituted by a hydraulic damper device provided to suppress the vertical displacement of the bent portion of the brace.
A hydraulic damper device can be suitably used as the buffer member.

  An embodiment in which the present invention is applied to suitably reinforce the lower part on the front side of the vehicle body will be described. As shown in FIGS. 1 and 2, a pair of front side members 1, 1 extending in the front-rear direction on both the left and right sides are provided substantially parallel to the lower part on the front side of the vehicle body. The left and right front side members 1, 1 are bent at the rear end of the extending portion 1 a extending to the front engine room side to form an inclined portion 1 b extending obliquely downward, and extending backward from the lower end of the inclined portion 1 b. The end 1c is one step lower than the extension 1a. The base end portion 1c is coupled along the lower surface of the passenger compartment floor F.

  Front suspension cross members (hereinafter simply referred to as front cross members) 2 are installed in the vehicle width direction on the left and right front side members 1 and 1 below the boundary between the extending portion 1a and the inclined portion 1b. The front cross member 2 is formed in a substantially frame shape having an opening at the center.

  The front cross member 2 is fastened with bolts at the front portions 25 at the left and right ends to the lower rear ends of the extending portions 1a of the left and right front side members 1 and 1, and the rear portions 26 at the left and right ends are intermediate between the lower surfaces of the left and right inclined portions 1b. It is bolted in place. The front cross member 2 is disposed at a position where the height of the lower surface of the front cross member 2 is substantially the same as or slightly lower than the base end portion 1 c of the front side member 1.

  Lockers 3 and 3 are provided along the left and right side edges of the passenger compartment floor F. The left and right rockers 3, 3 are installed at substantially the same height as the base end portion 1c of the front side member 1, and the floor cross members 40 whose front ends extend in the vehicle width direction along the left and right front edges of the passenger compartment floor F, respectively. , 40 are connected to the front ends of the base end portions 1c of the left and right front side members 1,1. Further, a floor cross member 4 is installed at the middle position between the left and right lockers 3 and 3 along the upper surface of the passenger compartment floor F in the vehicle width direction. The floor cross member 4 is connected to the left and right front side members 1. , 1 so as to intersect with the base end portion 1c. 2D shows a dash panel that stands up from the front edge of the passenger compartment floor F. FIG.

  The left and right rockers 3 and 3 and the central portion in the width direction of the front cross member 2 are connected in a substantially V shape in plan view by a pair of left and right braces 5 and 5. The left and right braces 5 and 5 are the same, and are made of a metal round pipe material. The middle part in the longitudinal direction is bent into a gentle obtuse angle and is formed in a substantially square shape that opens upward. The bending portion 51 in the middle of the brace 5 has a bending angle set to about 160 degrees. Both ends 52 and 53 of the brace 5 are flattened by crushing the pipe material up and down, and mounting portions provided with bolt through holes are formed.

  The left and right braces 5, 5 are bolted together with the mounting portions of the base ends 52, 52 superimposed on the lower surfaces near the front ends of the left and right rockers 3, 3, respectively. Extending obliquely. And the attachment part of each front-end | tip 53 and 53 of both 5 and 5 is piled up and down, and it bolts and connects with the front lower surface of the center part of the vehicle cross direction of the front cross member 2. The front ends 53 of the left and right braces 5, 5 may be connected adjacent to each other in the vehicle width direction near the center of the front cross member 2 in the vehicle width direction.

  The bent portions 51 and 51 of the left and right braces 5 and 5 are arranged in front of the front edge of the passenger compartment floor F and at lower positions corresponding to the inclined portions 1b and 1b of the left and right front side members 1 and 1, respectively. is there. Dampers 6 and 6 serving as buffer members are installed between the bent portions 51 and 51 and the inclined portions 1b and 1b in the vertical direction.

  As shown in FIGS. 3A and 3B, the damper 6 is a well-known hydraulic damper, and includes a cylinder 60 and a piston rod 61 assembled to the cylinder 60 so as to be able to extend and contract. The cylinder 60 is partitioned into two chambers in the longitudinal direction by a piston 63 of a piston rod 61 slidably fitted from one end thereof, and a first oil chamber r1 and a second oil chamber r2 are formed. The one end of the cylinder 60 is closed by a lid member 66 that is inserted through the rod body, and both the oil chambers r1 and r2 are filled with oil.

  The piston 63 is provided with a plurality of orifices (small holes) 64, 65 through which oil can move between the first oil chamber r1 and the second oil chamber r2, and one of the orifices 64 is provided when the piston rod 61 is extended. There is provided a valve that allows movement of the oil from the first oil chamber r1 to the second oil chamber r2, while prohibiting movement during contraction. The other orifice 65 is provided with a valve that allows the oil to move from the second oil chamber r2 to the first oil chamber r1 when contracted and prohibits the movement when extended. In the damper 6, the oil flows through the orifices 64 and 65 by the expansion and contraction operation of the piston rod 61, and the expansion and contraction operation of the piston rod 61 is suppressed by the flow resistance of the oil. Further, it is not always necessary to use a damper provided with a valve in each of the orifices 64 and 65, and a damper without a valve may be used.

  The dampers 6 and 6 are pivotally supported on the side surfaces of the inclined portions 1b and 1b of the left and right front side members 1 and 1 by a support shaft that passes through a ring-shaped attachment provided at the other end (upper end) of the cylinder 60. It is connected so as to be swingable in the front-rear direction. The lower end of the piston rod 61 is provided with a ring-shaped mounting portion at the lower end of the piston rod 61 via a bracket that is swingably connected back and forth in the longitudinal direction of the brace by a support shaft that penetrates the left and right braces 5 and 5 in the width direction. The left and right braces 5, 5 are connected to the bent portions 51, 51 in a swingable manner. The lower ends of the dampers 6 and 6 may be pivotally supported directly on the side surfaces of the bent portions 51 and 51 of the braces 5 and 5 without using the bracket.

When the vehicle is running, the extension portions 1a and 1a of the left and right front side members 1 and 1 are displaced in the up and down phase around the center line in the vehicle width direction between the two 1a and 1a due to input from the front suspension or the like. Torsional vibration will occur. In this case, in the front cross member 2 installed below the left and right extending portions 1a and 1a, the center portion in the vehicle width direction is displaced and oscillated left and right.
In the present embodiment, the front and rear rockers 3 and 3 on the left and right sides of the passenger compartment floor F and the pair of left and right braces 5 and 5 that connect the center portion in the vehicle width direction of the front cross member 2 in a V shape in plan view. The left and right displacement vibrations of the cross member 2 are suppressed, and the torsional vibrations of the extending portions 1a and 1a of the left and right front side members 1 and 1 are suppressed.

  In this case, since the left and right braces 5 and 5 are formed in a substantially square shape that opens upward and is given deformability, the vehicle interior is more than that using a straight brace (FIG. 8). The lateral displacement restraining force of the floor F is slightly small, and the braces 5 and 5 change the bending angle of the bent portion 51 and the bent portion 51 is displaced in the vertical direction, but between the bent portion 51 and the body part above it. Since the damper 6 is provided, the vertical displacement of the bent portion 51 is damped by the spring elasticity of the damper 6, whereby the torsional vibration of the vehicle body is damped, and a good riding comfort without a jerky feeling can be realized. .

  When the bending angle of the bent portion 51 is set to an obtuse angle, the left and right braces 5 and 5 have an increased amount of vertical displacement of the bent portion 51 with respect to a change in the interval between the connecting portions of both ends 52 and 53. Efficient damping effect is achieved. However, when the bending angle approaches 90 degrees, the enlargement rate of the displacement amount decreases, and conversely, when approaching a straight line, the enlargement rate increases, but the tension force becomes too strong. The bending angle of the braces 5 and 5 is preferably set to about 150 to 170 degrees.

  In the above-described embodiment, the front lower part of the vehicle body is reinforced, but it is also preferable to reinforce the rear lower part of the vehicle body. Hereinafter, another embodiment for reinforcing the rear lower portion of the vehicle body using the present invention will be described with reference to FIGS. 4 and 5. The basic structure of this embodiment is almost the same as that of the previous embodiment, and the same members are denoted by the same reference numerals and their detailed description is omitted.

  Left and right rear side members 7, 7 extending rearward from the vehicle inner side surfaces are connected to the rear ends of the left and right rockers 3, 3, respectively. The left and right rear side members 7 and 7 have a plan view, an inclined portion 7b that is obliquely rearward and inward from the connecting portion at the rear end of the rocker 3 and 3, and an extended portion 7a that is bent from the rear end and extends rearward. I have. The rear side members 7 and 7 are formed in an arch shape that protrudes upward in a side view from the connecting portion of the rear end of the rockers 3 and 3 to the rear end.

  A frame-shaped rear suspension cross member (hereinafter simply referred to as a rear cross member) 8 is provided between the left and right rear side members 7. The front and rear portions of the left and right ends of the rear cross member 8 are bolted and fixed to the lower surfaces of the inclined portions 7b and 7b of the left and right rear side members 7 and 7 and the lower surfaces of the extending portions 7a and 7a, respectively. The rear frame portion 82 of the rear cross member 8 has a lower surface disposed at substantially the same height as the lower surface of the rocker 3.

  The rear ends of the left and right rockers 3 and 3 and the rear edge side of the rear cross member 8 in the center in the vehicle width direction are connected to each other in a substantially V shape in plan view by left and right braces 5 and 5. The left and right braces 5 and 5 are connected by bolting the base ends 52 and 52 to the lower surfaces of the rear ends of the left and right rockers 3 and 3, respectively, and extend obliquely rearward and inward of the vehicle from these connecting portions. The attachment portions of the tips 53 and 53 are connected by bolting adjacent to the vicinity of the center portion in the vehicle width direction on the lower surface of the rear cross member 8. The front ends 53 of the left and right braces 5 and 5 may be overlapped and connected to the center of the rear cross member 8 in the vehicle width direction.

  Bent portions 51, 51 in the middle of the left and right braces 5, 5 are provided at positions closer to the base end 52 than the front and rear central portions, respectively, and lower positions corresponding to the inclined portions 7b, 7b of the left and right rear side members 7, 7. It is arranged in. Dampers 6 and 6 are installed in the vertical direction between the bent portions 51 and 51 and the inclined portions 7b and 7b. Each of the dampers 6 and 6 pivotally supports the mounting portion at the upper end of the cylinder 60 on the side surfaces of the inclined portions 7b and 7b of the left and right rear side members 7 and 7 so as to be swingable in the front-rear direction. Is pivotally supported on the side surfaces of the bent portions 51, 51 of the left and right braces 5, 5 by a support shaft.

  According to this embodiment, the same effect as the previous embodiment is obtained, and the combination of the brace 5 and the damper 6 exhibits the spring performance and exhibits the effect of improving riding comfort while attenuating torsional vibration.

  Next, still another embodiment of the present invention for reinforcing the lower part on the front side of the vehicle body will be described with reference to FIGS. The basic structure of the present embodiment is substantially the same as that of the first embodiment, and differences will be mainly described. In the drawings, the same members are denoted by the same reference numerals.

  As shown in FIGS. 6 and 7, in the reinforcing structure of the present embodiment, the intermediate bent portion 51 of the left and right braces 5 and the front side member 1 are connected to each other by a damper 6 </ b> A that has a vertically inclined inclination posture. is there. Each damper 6A is of the same type as the damper 6 of the previous embodiment and has a longer overall length than that of the previous embodiment. The damper 6 </ b> A is in a forward inclined posture with an inclination angle of 30 ° to 60 ° with respect to the horizontal direction, and the upper end of the cylinder 60 is connected to the connecting portion between the inclined portion 1 b of the front side member 1 and the rear portion 26 of the front cross member 2. The lower end of the piston rod 61 is pivotally supported by the bent portion 51 of the brace 5 so as to be swingable in the front-rear direction.

Further, the bent portion 51 of the brace 5 is connected to the base end portion 1c of the front side member 1 along the lower surface of the passenger compartment floor F by an auxiliary member 9 inclined in the opposite direction to the damper 6A.
The auxiliary member 9 is formed of a strip-shaped body or pipe material having a shallow cross-sectional shape with a reinforcing flange on both left and right edges made of a metal plate. The auxiliary member 9 is bolted at the lower end to the bent portion 51 of the brace 5 and has a rearward inclination of 60 ° to 30 ° with respect to the horizontal direction upward and backward from the bent portion 51, and the upper end 91 is the front side member. 1 is fixed to the lower surface of the base end portion 1c by bolting.

  The angle between the damper 6A and the auxiliary member 9 is set to an obtuse angle and is set to a range of about 90 ° to 120 °.

  According to the present embodiment, there is a space below the inclined portion 1b of the front side member 1 at the lower part of the vehicle body, and it is easy to secure a damper installation space, and the damper 6A is inclined, so the fixed portion on the inclined portion 1b side The distance from the bent portion 51 of the brace 5 can be increased, and the damper 6A can be made large in length and longer than the damper 6 installed in the vertical direction of the previous embodiment. Therefore, the damper 6A is economical because it can use a low-cost damper that is generally mass-produced and has high vibration damping performance.

  When the torsional vibration of the front side member extending portion 1a by the brace 5 is suppressed, if a force that moves the bent portion 51 of the brace 5 in the vertical direction acts on the bent portion 51, the rearward tilt assists connecting the bent portion 51 and the lower portion of the vehicle body. The member 9 swings up and down around the joint portion between the upper end 91 and the base end portion 1C of the front side member 1, and the displacement of the bent portion 51 of the brace 5 thereby causes the auxiliary member 9 around the joint portion. It is regulated along the arcuate track at the lower end, and the displacement direction of the bent portion 51 and the expansion / contraction direction of the forwardly inclined damper 6A substantially coincide with each other, so that the displacement of the bent portion 51 is attenuated by the damper 6A. Therefore, as in the previous embodiment, it is possible to realize a good ride comfort while attenuating torsional vibration of the vehicle body.

  In this embodiment, it is used to reinforce the front lower part of the vehicle body, but may be used to reinforce the rear lower part of the vehicle body.

  In addition, all the above-mentioned several embodiment is an illustration in all the points, and does not limit the scope of the present invention, The present invention includes what variously modified and changed the above-mentioned embodiment. For example, in each of the above-described embodiments, the vehicle compartment floor side and the front or rear suspension cross member are connected by braces, but the suspension cross member is not limited to the suspension cross member, and is installed between the front or rear side members for other purposes. A cross member may be used. The brace is not limited to a pipe material but may be a bar material. The damper is not limited to a hydraulic type, and viscoelastic rubber is sandwiched between two metal plates, the upper end of one metal plate is fixed to the vehicle body side, and the lower end of the other metal plate is fixed to the bent portion side of the brace. It is good also as a structure to do.

It is a schematic plan view which shows embodiment which applied the reinforcement structure of this invention to the lower part of the front side of a vehicle body. It is a schematic side view of the said embodiment. 3 (A) and 3 (B) are explanatory views showing the operation of the damper as a buffer member used in the present invention. It is a schematic plan view which shows other embodiment which applied the reinforcement structure of this invention to the lower part of the rear side of a vehicle body. It is a schematic side view of the said embodiment. FIG. 10 is a schematic plan view showing still another embodiment in which the reinforcing structure of the present invention is applied to the lower part on the front side of the vehicle body. It is a schematic side view of the said embodiment. It is a schematic plan view which shows the lower reinforcement structure of the conventional vehicle body.

Explanation of symbols

F Car floor 1 Front side member (side member)
1a Extension part 2 Front suspension cross member (cross member)
3 Rocker 5 Brace 51 Bent part 52 Base 53 53 Tip 6, 6A Damper (buffer member)
7 Rear side member (side member)
7a Extension part 8 Rear suspension cross member (cross member)
9 Auxiliary members

Claims (8)

The left and right side positions on the lower side of the passenger compartment floor and the center part in the vehicle width direction of the cross member that is installed between the extension parts of the left and right side members that extend from the passenger compartment floor are substantially planar in a pair of left and right braces. In the reinforcement structure at the bottom of the car body connected in a V shape,
Each brace is formed into a generally square shape that is bent in a gentle obtuse angle at its longitudinal intermediate position and opens upward.
Connect the base end of each brace to the rocker installed along the left and right side edges of the passenger compartment floor, connect the tip to the center of the cross member,
A reinforcing structure for a lower part of a vehicle body, wherein a middle bent part of the brace and a lower part of the vehicle body above the bent part are connected in a vertical direction by a buffer member. In the reinforcing structure for the lower part of the vehicle body according to claim 1,
The vicinity of the front ends of the left and right rockers and the central portion in the vehicle width direction of the front suspension cross member that is installed between the extending portions extending forward from the passenger compartment floor of the left and right front side members are connected by the brace. Reinforcement structure at the bottom of the car body. In the reinforcing structure for the lower part of the vehicle body according to claim 1,
The brace connects the vicinity of the rear ends of the left and right rockers and the central portion in the vehicle width direction of the rear suspension cross member that extends between the extension portions extending rearward from the passenger compartment floor of the left and right rear members. Reinforcement structure at the bottom of the car body. The reinforcing structure for the lower part of the vehicle body according to claim 1,
The above brace is a reinforcement structure for the lower part of the vehicle body, with the bending angle of the bending part set in the range of 150 to 170 degrees. The reinforcing structure for the lower part of the vehicle body according to claim 1,
The cushioning member is mounted between the middle bent part of the brace and the lower part of the vehicle body in an up-down direction and in an inclined manner, and the bent part and the lower part of the vehicle body are connected in an inclined posture opposite to the inclined posture of the buffer member. A reinforcing structure for the lower part of the vehicle body provided with auxiliary members that are connected in an up-down direction and in an inclined manner. In the reinforcement structure of the lower part of the vehicle body according to claim 5,
The buffer member is provided so as to connect the extending portion of the side member extending from the passenger compartment floor and the intermediate bent portion of the brace in an inclined posture in the vertical direction,
A reinforcing structure for a lower part of a vehicle body, wherein the auxiliary member is provided so as to connect the base end portion of the side member along the lower surface of the passenger compartment floor and the intermediate bent portion of the brace in an inclined posture in the vertical direction. In the reinforcement structure of the lower part of the vehicle body according to claim 5 or 6,
A reinforcing structure for a lower part of a vehicle body, in which an opening angle between the buffer member and the auxiliary member is obtuse. The reinforcement structure for the lower part of the vehicle body according to claim 1,
A reinforcing structure for a lower part of a vehicle body constituted by a hydraulic damper device provided as the buffer member so as to suppress the vertical displacement of the bent portion of the brace.