JPH0611905Y2 - Automotive floor tunnel structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a structure of a floor tunnel portion of an automobile, and more particularly to a vehicle body structure for improving the strength of the vehicle body around the floor tunnel portion.

(Prior Art and Problems Thereof) In general, an automobile floor has a tunnel portion projecting from a front end to a rear portion in a central portion thereof, and a rear portion of a transmission, a propeller shaft, and the like are disposed inside an outer surface of the floor of the tunnel portion. It has become so. And
It is usual that a cross member having a substantially hat-shaped cross section that is orthogonal to the tunnel portion is joined and fixed to the upper surface of the floor, and the cross member secures the rigidity of the central portion of the vehicle body.

However, in the above structure, at the intersection of the cross member and the tunnel portion, if the height of the cross member at the intersection is kept low in order to widen the space in the vehicle compartment, the cross-section height of the cross member will decrease. There is a problem that the upper part becomes insufficient and the strength becomes insufficient, and on the other hand, if the height of the cross member at the intersection is made sufficient to secure the strength, this causes an obstacle in the vehicle interior. There is a floor structure in which a constriction portion is formed in a tunnel portion at an intersection with a member to secure a required cross-sectional height of the cross member at the intersection, and at the same time, the protrusion into the vehicle compartment is minimized.

Further, as disclosed in Japanese Utility Model Laid-Open No. 61-196880, the required cross-sectional height of the cross member is secured without forming a constricted portion in the tunnel portion, and the amount of protrusion in the vehicle compartment at the intersection portion between the tunnel portion and the cross member is secured. There is also a floor structure that tries to minimize this.

However, in the above conventional structure, when the vehicle body structure is a so-called open top structure without a roof above the passenger compartment,
Since the structure of the roof part is not provided, the rigidity of the vehicle body is insufficient compared to a vehicle body of a general structure (vehicle body with a roof). Therefore, due to vibration during running and lateral G during cornering, the vehicle body There is a problem in that the influence of bending, twisting, etc. on the vehicle body increases, and the increased stress concentrates around the floor tunnel portion at the center of the vehicle body, resulting in insufficient strength around the floor tunnel portion.

Further, in the case where the stress concentration is repetitive, such as repeated application, there is a risk of cracking around the joint between the floor tunnel and the cross member, which is a safety problem.

Therefore, it is conceivable to increase the thickness of each member around the floor tunnel portion such as the cross member and the floor panel to improve the rigidity. However, in this case, the thickness of each member must be considerably increased. As a result, the weight of the vehicle body becomes too heavy, which is contrary to the recent trend of weight reduction of the vehicle body, which deteriorates traveling performance such as fuel consumption and acceleration performance.

(Object of the Invention) In view of the above circumstances, an object of the present invention is to provide a structure of a floor tunnel portion of an automobile capable of increasing the rigidity around the floor tunnel portion without impairing the weight reduction of the vehicle body. .

(Structure of the Invention) In order to achieve the above object, the floor tunnel structure of an automobile according to the present invention is one in which a cross member is provided on the upper surface of the floor panel having a tunnel portion, and the cross member has side sills at both ends. The first cross member is joined to form a closed cross section between the floor panel and the floor panel, and the first cross member is joined to the upper portion of the tunnel part so as to form a closed cross section between the first cross member and both ends of the side sill. Joined,
A second cross member joined to the upper portion of the first cross member so as to form a closed cross section with the first cross member;
And a connecting member for connecting the vertical wall of the second cross member and the upper portion of the tunnel portion to each other, whereby the increase in the vehicle body weight is suppressed to a necessary minimum and the rigidity around the floor tunnel portion is improved. Is intended.

Embodiments of the Invention Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a floor tunnel portion of an automobile having an open top structure to which an embodiment of the vehicle floor tunnel portion structure according to the present invention is applied.

Reference numeral 1 is a floor, 2 is a tunnel portion formed by projecting a central portion of the floor 1 upward, and is formed in a front-rear direction of a vehicle body. Inside the tunnel portion 2, a rear portion of a transmission (not shown) is arranged in a front portion, A propeller shaft that transmits driving force to the rear wheels runs from the transmission to the rear.

3 is a cross member in which two substantially hat-shaped cross sections are stacked,
The cross member 3 is joined and fixed to the upper surface of the floor 1 at the partition between the passenger compartment floor and the trunk floor, and the side sill has a substantially rectangular closed cross section with its both ends extending in the vehicle front-rear direction at the vehicle side ends of the floor 1. It is bonded and fixed to the inner wall of No. 4.

The cross member 3 is composed of a lower cross member 3A and a cross member 3B covering the lower cross member 3A. The lower cross member 3A follows the tunnel portion 2 protruding at the center of the floor 1. It has a normal shape with a raised central portion, and has a structure in which a cross member 3B having a flat upper surface is joined and fixed onto this, and the raised portion of the central portion of the lower cross member 3A is covered to flatten the trunk floor. It was devised to achieve this.

According to the conventional structure, the floor tunnel portion around the center of the vehicle body has sufficient strength as described above. However, in this embodiment, the vehicle body is an open top structure and there is no roof structure. , The rigidity of the car body is insufficient compared to the car body with a general structure (car body with roof),
Therefore, the influence on the vehicle body such as bending and twisting applied to the vehicle body due to the vibration during traveling and the lateral G during cornering increases, and the increased stress concentrates around the floor tunnel portion at the center of the vehicle body. , Tunnel part 2 in the center of the vehicle
The stress concentrates around the intersection of the cross member 3 and the cross member 3, and the strength of this portion is insufficient.

Therefore, the tunnel reinforcement 5 as a reinforcing member connects the tunnel portion 2 and the cross member 3 to reinforce the floor tunnel portion at the center of the vehicle body.

The tunnel reinforcement 5 has a substantially L-shaped cross section formed by the flange portion 5A of the connecting portion with the upper surface of the tunnel portion 2 and the connecting portion of the vertical wall of the cross member 3, and the center of the cross member 3 is formed. At the intersection with the tunnel portion 2, the vertical wall of the cross member 3 and the upper surface of the tunnel portion 2 are joined and fixed so as to be connected.

FIG. 2 is an enlarged perspective view in which a part of the periphery of the floor tunnel portion of FIG. 1 is disassembled. And FIG. 3 is a sectional view taken along the line AA in FIG.

With such a structure, the thickness around the intersection of the tunnel member 2 and the cross member 3, which is the center of the vehicle body where stress concentration is expected, becomes thicker by the thickness of the tunnel reinforcement 5, and moreover, the tunnel. The section 2 and the cross member 3 are integrally connected by the tunnel reinforcement 5.

Therefore, the stress concentrated at the intersection of the tunnel portion 2 and the cross member 3 is dispersed over the entire joint area of the tunnel reinforcement 5 integrally connected thereto, and as a result, the floor tunnel The rigidity around the part is relatively improved.

Therefore, even when the vehicle body has an open top structure, the strength of the periphery of the floor tunnel portion can be ensured by bonding and fixing the tunnel reinforcement 5.

Moreover, since the weight of the vehicle body is increased only by the minimum required tunnel reinforcement 5, the rigidity is improved without impairing the weight reduction of the vehicle body.

Here, the length of the flange portion 5A joined to the upper surface of the tunnel portion 2 of the tunnel reinforcement 5 is set to the flange of the cross member 3B with the tunnel portion 2 as in the sectional view of the other embodiment shown in FIG. Even if the length is shortened, the stress concentrated at the intersection of the tunnel portion 2 and the cross member 3 should be sufficiently dispersed even in the slightly reduced joint area of the tunnel reinforcement 5 shown in FIG. Thus, sufficient strength can be secured as in the embodiment shown in FIG.

(Effects of the Invention) According to the floor tunnel portion structure of an automobile according to the present invention as described above, the rigidity around the floor tunnel portion at the center of the vehicle body where stress concentration can be considered is improved without impairing the weight reduction of the vehicle body. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a floor tunnel portion of an automobile having an open top structure to which an embodiment of the floor tunnel portion structure according to the present invention is applied, and FIG. 2 is an exploded view of a part around the floor tunnel portion of FIG. FIG. 3 is an enlarged perspective view, FIG. 3 is a sectional view taken along the line AA in FIG. 1, and FIG. 4 is a first embodiment of another embodiment.
It is sectional drawing of the AA line in the figure. 2 ... Tunnel part 3 ... Cross member 5 ... Tunnel reinforcement (connecting member) 5A ... Flange part

Claims (1)

[Scope of utility model registration request] 1. A cross member provided on the upper surface of a floor panel having a tunnel portion, wherein both ends of the cross member are respectively joined to side sills to form a closed cross section with the floor panel, A first cross member is joined to the upper part of the tunnel portion so as to form a closed cross section with the first cross member, and both ends are joined to side sills, respectively, and is closed to the upper part of the first cross member. A floor of an automobile, comprising: a second cross member joined so as to form a cross section; and a connecting member that connects the vertical walls of the first and second cross members and the upper portion of the tunnel portion. Tunnel structure.