JPH10316011A - Vehicle frame structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unnecessary operation of an airbag while a vehicle comes into collision at a low speed and ensure safety of an occupant while it comes into collision at high speed. SOLUTION: This vehicle frame structure is provided with right and left front side members 1 constituted of, in a rough Y-shape, a main member 2 reinforced by fitting an reinforcement 5 in the longitudinal direction and a sub member 3 extending aslant forward from around the front end of the main member 2, and is formed so that the front end of the main member 2 and the front end of the sub member 3 are connected to a front cross member 4. The position of the front end of the sub member 3 is set at the more backward position than the front end of the main member 2 and the position of the reinforcement 5 is set at the more backward position than the front end of the main member 2 to form a non-reinforced part 24 at the front end part of the main member 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle frame structure, and more particularly to a vehicle front frame structure.

[0002]

2. Description of the Related Art A frame of a vehicle such as a van-type vehicle or a wagon-type vehicle having a passenger compartment in front of a vehicle body is designed to withstand a collision load during a high-speed collision of the vehicle in order to ensure the safety of the occupant. In this case, it is necessary to reduce the crushing range of the frame to a range as short as possible from the front end of the frame, and to efficiently absorb the collision energy during that time.

As shown in FIG. 7, this type of frame structure generally has a high rigidity main body in which left and right front side members 1A (only one of which is shown) are provided with a reinforcement 5A in the longitudinal direction. Member 2A and sub-member 3 extending obliquely outward and forward from main member 2A
A is formed in a substantially Y-shape, and a structure in which the tip of the main member 2A and the tip of the sub-member 3A are both connected to the front cross member 4A minimizes the crushing range against an impact load during a high-speed collision. .

A front side member 1 formed in a Y-shape
Since A has a high rigidity with an emphasis on safety during a high-speed collision, the front side member 1A does not collapse and cannot absorb the collision energy in a low-speed collision of the vehicle. In a vehicle that detects the deceleration of the vehicle and activates the airbag, the airbag system operates even during a low-speed collision. Therefore, to avoid activating the airbag system during a low-speed collision,
At the front position of the main member 2A, a shock-absorbing member 6 protruding forward is attached to the front surface of the front cross member 4A. The shock-absorbing member 6 is crushed during a low-speed collision to absorb the collision energy and reduce the deceleration of the vehicle. Lower.

[0005]

However, in the above-described frame structure, since the separate shock absorbing member 6 is mounted, the cost is increased and the mounting process is increased accordingly. The shock absorbing member 6 is a front cross member 4A.
Projecting from the front of the vehicle by about 40 mm to 70 mm, the degree of freedom in mounting other members constituting the front of the vehicle such as a front bumper is restricted. In view of the above, the present invention eliminates unnecessary operation of the airbag by efficiently absorbing the collision energy at the time of a low-speed collision without providing a separate member such as an impact absorbing member, and eliminates unnecessary operation of the airbag. An object of the present invention is to realize a vehicle frame structure that can absorb and improve safety.

[0006]

The present invention comprises left and right front side members and a front cross member extending between the front ends of the front side members. Each front side member is provided with a reinforcement in the longitudinal direction. A vehicle frame having a substantially Y-shape comprising a reinforced main member and a sub-member extending obliquely forward and outward from near the front end of the main member, wherein the front end of the main member and the front end of the sub-member are connected to the front cross member. In the structure, the sub-member sets the position of the tip thereof to a position retracted from the tip of the main member, while setting the position of the tip of the reinforcement to a position retracted from the tip of the main member, A non-reinforced portion is formed at the front end of the member (claim 1). At the time of low-speed collision of the vehicle, the non-reinforcement portion at the front end of the main member is crushed to absorb the collision energy, and the deceleration of the vehicle can be reduced.

[0007] The position of the front end of the reinforcement is set at a position forward of the connecting portion between the main member and the sub member, and retracted from the front end of the sub member. The front side member has a structure in which the rigidity increases stepwise from the front end to the rear, and can efficiently absorb the collision energy during a high-speed collision.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a pair of left and right front side members 1 extending in the front-rear direction of a vehicle frame.
(The figure shows one of them) The main member 2 and the sub-member 3 projecting obliquely outward and forward from the main member 2 are substantially Y-shaped. The front end of the main member 2 and the front end of the sub member 3 are connected to the front cross member 4.

As shown in FIGS. 1 to 3, the main member 2 is composed of a main lower 21 having a substantially U-shaped cross section with an open upper portion, and flat upper main portions 22 and 22a for closing the opening of the main lower 21. It has a cross-sectional structure, and its front end is slightly bent toward the center of the vehicle. The main upper portion 22a of the bent portion is substantially Y extending to the sub-member 3 side.
It has a character shape. Further, the general part 23 of the main member 2
Is provided with a reinforcement 5 therein.
The reinforcement 5 is a flat plate, and the main lower 2
1, the left and right side edges of the reinforcement 5 are welded and fixed to the left and right side walls of the main lower 21, respectively, so as to span between the left and right side walls of the main lower 21 at an intermediate position in the vertical direction within the main member 2. 23 is reinforced as an upper and lower two-stage closed sectional structure (FIG. 2B). In addition, the tip of the reinforcement 5 is set to the main member 2.
2A is set at a substantially intermediate position between the tip of the main member 2 retreated by about 400 mm from the tip of the main member 2 and the bent portion, and the main member 2 has a non-reinforcing portion 24 in front of the reinforcement 5 (FIG. 2A). )). The front end of the non-reinforcing portion 24 is fitted and welded into the opening of the front cross member 4 having a substantially U-shaped cross section which opens rearward.

Similar to the main member 2, the sub-member 3 has a closed cross-sectional structure composed of a sub-lower 31 having a substantially U-shaped cross section and a sub-upper 32 of a flat plate body, and a base end portion 33 is connected to a bent portion of the main member 2. Then, it extends obliquely outward and forward of the main member 2. Base end 33 of sub-member 3
The sub-lower 31 extends rearward from the sub-upper 32, and has a substantially L-shaped cross section that is open to the main member 2 side by cutting out the inner side wall of the extended sub-lower 31. Then, as shown in FIG. 2 (C), the main member 2 is fitted into the opening of the base end portion 33 of the sub-member 3 and is formed into a Y-shape so that the front intersection angle between the two 2 and 3 forms an acute angle. The sub-lower 31 is welded by overlapping the bottom surface of the sub-lower 31 on the bottom surface of the main member 2 and the extension of the main upper 22a is welded to the upper surface of the base end of the sub-lower 31.

As shown in FIGS. 1 and 3, the size of the sub member 3 is shorter than that of the front portion from the bent portion to the tip of the main member 2, and the position of the tip of the sub member 3 is such that the main member 2 is not reinforced. At the horizontal position outside the portion 24, it retreats backward from the tip of the main member 2, extends forward from the tip of the reinforcement 5, and
Is located at a position substantially corresponding to the middle part of The distal end of the sub-member 3 is welded and fixed to a side end portion which is bent from the above-mentioned coupling portion coupled to the distal end of the non-reinforcing portion 24 of the main member 2 of the front cross member 4 and extends obliquely rearward and outward.

As shown in FIG. 3, the dimension of the section X (retraction of the tip of the sub-member 3) from the tip of the main member 2 to the tip of the sub-member 3 is determined when the vehicle is in a low-speed collision.
The dimensions are set so that the non-reinforcing portion 24 of the main member 2 is crushed to absorb the collision energy. Further, the dimension of the section Y from the distal end position of the sub member 3 to the distal end position of the reinforcement 5 is such that when the vehicle collides at a relatively high speed, the non-reinforced portion 24 of the main member 2 and the sub member 3 are both crushed. The dimensions are set to be necessary to absorb the collision energy. Further, when a large collision energy equal to or larger than the collision energy is generated, the front side member 1 is moved from the front end so that the collision energy is absorbed in the section Z where the reinforcing portion 23 of the main member 2 and the sub-member 3 are combined. The structure is such that the rigidity gradually increases toward the rear.

The frame of the vehicle according to the present invention has a front side member having the same structure as that of the above-mentioned front side member 1 and is symmetrical to the front side member 1. The front side member is connected to the other side end of the front cross member 4. It is composed.

A low-speed and high-speed collision experiment of the vehicle frame of the present invention was performed, and the results are shown in FIGS. 4, 5 and 6. FIG. 4 shows the deformation of the frame after a low-speed collision.
6 shows the deformation of the frame after a high-speed collision, and FIG. 6 shows the deceleration applied to the vehicle.
The chain line represents the deceleration at the time of a high-speed collision.

At the time of a low-speed collision, as shown in FIG. 4, the section X (FIG. 3) where the rigidity of the front side member 1 is the lowest,
That is, only the front end of the non-reinforcing portion 24 of the main member 2 is crushed and absorbs the collision energy of a low-speed collision. in this case,
As shown in FIG. 6, the maximum value A of the deceleration of the vehicle can be kept low, and the airbag does not operate.

At the time of a high-speed collision, as shown in FIG. 5, the section X (FIG. 3) of the front side member 1 is first collapsed,
Subsequently, the section Y (FIG. 3), that is, the middle rigid portion where the non-reinforced portion 24 of the main member 2 and the sub-member 3 are combined is crushed to absorb the collision energy. In this case, as shown in FIG. 6, the maximum value B of the deceleration of the vehicle becomes high, and when this is detected, the airbag is activated.

Therefore, the difference C between the maximum value A of the deceleration at the time of a low-speed collision and the maximum value B of the deceleration at the time of a high-speed collision can be clarified. At the time of a high-speed collision, the airbag is reliably operated to ensure the safety of the occupant. Further, the front side member 1 has a structure (section X, section Y, section Z) in which the rigidity increases stepwise from the front end to the rear side, so that a larger collision energy is provided in front of the front side member 1 including section Z. Part efficiently absorbs, prevents deformation of the passenger compartment,
The safety of the occupant can be ensured. Further, unlike the related art, since there is no need for an impact absorbing member protruding forward of the frame, the cost and the mounting process are not required, and there is no restriction on other members constituting the front part of the vehicle such as a bumper.

[0018]

According to the structure of the vehicle frame of the present invention, the frame itself can efficiently absorb the collision energy at the time of a low-speed collision without providing a separate member such as a shock absorbing member, and the unnecessary operation of the air bag is eliminated. And can improve safety by absorbing large collision energy even during high-speed collision.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a front portion of a frame structure according to the present invention.

2A is a sectional view taken along a line IIA-IIA in FIG. 1, FIG. 2B is a sectional view taken along a line IIB-IIB in FIG. 1, and FIG. 2) is a sectional view taken along the line IIC-IIC in FIG.

FIG. 3 is a plan view showing a front part of the frame structure of the present invention.

FIG. 4 is a plan view showing deformation of the frame at the time of a low-speed collision of the frame structure of the present invention.

FIG. 5 is a plan view showing a deformation of the frame at the time of a high-speed collision of the frame structure of the present invention.

FIG. 6 is a diagram showing measurement results of deceleration of a vehicle in the low-speed collision and high-speed collision experiments.

FIG. 7 is a perspective view showing a front part of a conventional frame structure.

[Explanation of symbols]

 Reference Signs List 1 front side member 2 main member 24 non-reinforced part 3 sub member 4 front cross member 5 reinforcement

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuyoshi Toda 100 Kanayama, Ichiriyama-cho, Kariya-shi, Aichi Pref.

Claims (2)

[Claims] 1. A front member comprising left and right front side members, and a front cross member extending between the front ends of the front side members. Each of the front side members is provided with a main member reinforced by providing reinforcement in a longitudinal direction; In a vehicle frame structure in which a front end of a member and a sub-member extending diagonally forward and outward are formed in a substantially Y-shape, and the front end of the main member and the front end of the sub-member are connected to the front cross member, the sub-member is located at the front end. While the position is set to a position retracted from the tip of the main member, the position of the tip of the reinforcement is set to a position retracted from the tip of the main member, and a non-reinforcing portion is provided at the front end of the main member. The frame structure of the vehicle formed with. 2. The vehicle frame structure according to claim 1, wherein a position of a front end of said reinforcement is set at a position forward of a connecting portion between said main member and said sub-member and retreated from a front end of said sub-member.