JPH07149255A - Car body front structure - Google Patents

Abstract

PURPOSE:To perform axial compressive deformation stably on a front side member to which a cross member is joined. CONSTITUTION:Inside of a front side member 11, a bulkhead (a partition wall material) 14 is arranged on the same plane with a car body rear side side surface of a joining part of a cross member 13 joined to this front side member 11, and the starting points to start buckling deformation of respective face plates of the front side member 11 are made to coincide with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body front structure including front side members and cross members.

[0002]

2. Description of the Related Art A pair of front side members, which are disposed on both lower sides of an engine room at the front of a vehicle body, require high rigidity because a power unit, which is a heavy object, is mounted on the front side members. It is necessary to meet the demand, and therefore, it is formed in a pipe shape, and a rein hose is provided inside the pipe, and the front ends of both front side members are connected by cross members to increase the rigidity. (Japanese Patent Laid-Open No. 1-309881
(See the official gazette).

Further, for example, FIGS. 4 and 5 show an example of a conventional vehicle body front portion structure provided with front side members and cross members. A pair of pipe-shaped front side members 1 are arranged substantially parallel to the center line of the vehicle body, and front portions 1a thereof are arranged substantially horizontally at a predetermined height in the engine compartment and a rear portion 1b. Is welded to a dash panel 2 provided so as to be bent downward to define an engine room and a vehicle interior, and further dive under the lower end of the dash panel 2 to the vehicle interior side (right side in FIG. 4).
Is extended almost horizontally. Then, both ends 3a (one of which is not shown) of the front cross member 3 arranged in the direction orthogonal to the vehicle body center line are welded to the lower surfaces near the front ends of the front portions 1a of the front side members 1 on both sides. Has been done. By connecting the front end sides of both front side members 1 with the front cross member 3 in this manner, rigidity is enhanced.

[0004]

Therefore, in the above-mentioned conventional vehicle body front structure, since the front end portions of the left and right front side members 1 are connected by the front cross member 3, the lateral direction to the front side member 1 is increased. It is possible to increase the strength against the load and the like. However, when a load is applied in the axial direction of each front side member 1 at the time of a collision or the like, the four face plates constituting the square pipe-shaped front side member 1 respectively undergo compression buckling deformation. In the lower face plate to which the end portion 3a of the cross member 3 is joined, the compression buckling is restrained at the front cross member joining portion, so that the buckling deformation is newly started from this joining portion as a starting point (Fig. (See buckling waveform a in 5). On the other hand, since the other three face plates are not restrained, the deformation of the front cross member 1 from the front end continues (see the buckling waveform b in FIG. 5). As a result, as shown in FIG. 5, since the buckling waveform a of the lower face plate and the buckling waveform b of the other face plate do not match in phase, the forces interfere with each other and bending buckling easily occurs. Therefore, there is a problem that it is difficult to cause axial compression deformation as designed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle body front structure for stably causing axial compression deformation of a front side member in the event of a collision or the like.

[0006]

As a means for solving the above-mentioned problems, the present invention is directed to a square pipe-shaped member which is arranged substantially parallel to the center line of a vehicle body on both lower sides in the engine room at the front of the vehicle body. In the vehicle body front structure, each front side member is provided so as to be substantially orthogonal to the center line of the vehicle body, and both ends thereof are respectively connected to lower surfaces near the front ends of the front side members. Inside the side member, a partition wall material is fixedly provided on the inner peripheral surface on substantially the same plane as the vehicle body rear side surface of the joint portion of the cross member joined to the front side member.

[0007]

As described above, inside the front side member, the partition wall member is fixed to the inner peripheral surface on substantially the same plane as the vehicle body rear side surface of the connecting portion of the cross member connected to the front side member. Set up. As a result, when a compressive load acts on the front side member in the axial direction,
Each face plate of the front side member undergoes compression buckling deformation, and at this time, the cross member is coupled to the lower face plate, and inside the front side member,
Since the partition member provided on the same plane as the rear side surface of the cross member is provided, the compression buckling of each face plate is restrained at the cross member coupling portion where the partition member is provided. Therefore, each face plate of the front side member starts to deform starting from the position where the partition member is provided, and stable axial compression deformation occurs.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
It will be described based on.

In the vehicle body front structure of the present invention, a pair of square pipe-shaped front side members 11 (one of which is not shown) are arranged substantially parallel to the vehicle body center line on both lower sides of the engine room at the vehicle body front portion. Are arranged and each front part 11
The reference character a is disposed substantially horizontally at a predetermined height in the engine room, and the rear portion 11b is bent downward and is disposed substantially vertically so as to define the engine room and the vehicle interior. It is welded to the panel 12 and extends under the lower end of the dash panel 12 substantially horizontally to the inside of the vehicle compartment (right side in FIG. 1). Then, both ends 13a (one of which is not shown) of the front cross member 13 arranged in a direction orthogonal to the center line of the vehicle body are welded to the lower surfaces near the front ends of the front portions 11a of the front side members 11 on both sides. Has been done. By connecting the front end sides of both front side members 11 with the front cross member 13 in this manner, rigidity is enhanced.

Inside the front side member 11, on the same plane as the vehicle body rear side surface 13b of the connecting portion of the cross member 13 connected to the front side member 11, a bulkhead (a partition wall) having a U-shaped cross section is formed. Material) 1
4 is attached to the inner peripheral surface of the front side member 11 by being welded all around.

In FIG. 1, reference numeral 15 is a torque box, 16 is a suspension tower, and 17 is an apron upper member.

Next, the operation of this embodiment having the above-mentioned structure will be described. The front side member 11 arranged at the front part of the vehicle body has the front cross member on the outer lower surface inside the front part 11a. The bulkhead 14 is welded all around to the inner peripheral surface of the front part 11a so that the end part 13a of the front end 13a of the front crossmember 13 is joined to the side surface 13b of the front cross member 13 on the rear side of the vehicle body. Therefore, when a load is applied to the front side member 11 from the front during a vehicle collision, that is, when a compressive load acts in the longitudinal direction of the front side member 11, The face plates forming the four faces of the member 11 each undergo compression buckling deformation.

At this time, the lower face plate of the front portion 11a of the front side member 11 is the front cross member 13.
The compression buckling is constrained at this joint because they are joined together. Further, the three face plates on both sides and the upper side of the front portion 11a are connected to the lower face plate by the bulkhead 14 provided on the same plane as the side face 13b of the front cross member 13 on the rear side of the vehicle body. Even in one face plate, the compression buckling is restrained at the connection portion with the bulkhead 14.

Therefore, the front portion 11a of the front side member 11 is compressed and buckled by the load from the front.
In each of the face plates, the compression buckling is temporarily restrained at the connecting portion of the front cross member 13, that is, at the installation position of the bulkhead 14, so that the installation position on the vehicle body rear side of the installation position of the bulkhead 14 is As a starting point, a compressive buckling deformation is newly generated in each of the four face plates.

As a result, since the bulkhead 14 is provided inside the front portion 11a of the front side member 11 at the joint portion with the front cross member 13, as shown in FIG. Since the phase of the buckling waveform a generated on the side face plate and the phase of the buckling waveform b generated on the upper side plate and the side plate on both sides are the same, stable axial compression deformation can be achieved as compared with the case where the phases of the buckling waveforms are not the same. Occur.

[0016]

As described above, according to the vehicle body front structure of the present invention, the partition member is provided inside the front side member and substantially flush with the vehicle body rear side surface of the cross member coupled to the front side member. Since the front side member is fixed to the inner peripheral surface, when the axial load is applied to this front side member, the starting points of the compressive buckling deformation that act on each surface of the front side member are the same, which results in a stable shaft. Compressive deformation can be generated, and bending buckling deformation of the front side member can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of a vehicle body front structure of the present invention.

FIG. 2 is a sectional plan view of a front portion of a front side member in this embodiment.

FIG. 3 is an explanatory diagram showing a buckling waveform generated in the front part of the front side member in this embodiment.

FIG. 4 is a perspective view showing a main part of a conventional vehicle body front structure.

5 is an explanatory diagram showing a buckling waveform generated in the front part of the front side member in the structure of FIG.

[Explanation of symbols]

 11 Front Side Member 11a Front End 13 Front Cross Member 13a End 14 Bulkhead

Claims (1)

[Claims] 1. A square pipe-shaped front side member, which is disposed substantially parallel to a vehicle body center line, on both lower sides of an engine room at a front portion of the vehicle body, and is provided substantially orthogonal to the vehicle body center line, In a vehicle body front structure including a cross member whose both ends are respectively coupled to lower surfaces near front ends of the front side members, inside the front side members, the cross member coupled to the front side members is provided. A front structure of a vehicle body, characterized in that a partition wall material is fixedly provided on an inner peripheral surface on substantially the same plane as a rear side surface of the vehicle body at a connecting portion.