JP2000001183A - Front body structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the degree of freedom of the tuning of the collision performance as the frame unit by reducing the influence which the sub-frame installed on the front frame receives against the initial buckling deformation of the vehicle when the front of the vehicle is collided. SOLUTION: A sub-frame 3 consists of a front edge portion 4, a side edge portion 5 and an engine cross member 6. The forward portion of the sub-frame 3 and left and right front frames 1 are axially attached so that they can rotatively move via tie down hook members 7. When the front frames 1 start buckling deformation at front collision, the tie down hook members 7 are rotatively moved centered on the axially attached portion with a bolt 8a to the front of the vehicle relative to the front frames 1, which makes it difficult for the influence of the buckling deformation to be transmitted to the sub-frame 3. As a result, degree of freedom is increased in staggering the timing of starting the buckling deformation of the front frames 1 and the sub-frame 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A front portion of a vehicle is basically provided with left and right front frames having a closed cross section which are disposed in the front-rear direction along front wheel aprons constituting left and right side walls of an engine room. The front bumper is connected to the front end of the front frame by a bumper stay. At the time of a frontal collision, the front bumper is first crushed, and the collision load is input to the left and right front frames via the bumper beam and the bumper stay of the front bumper. The front frame buckles and deforms to absorb the collision energy. Usually, a hook such as a traction hook or a tie-down hook is fixed to the side surface of the front end portion of the front frame (for example, see Japanese Patent Laid-Open No.
-15030 gazette).

[0003] Furthermore, a cross-shaped sub-frame (engine support member) composed of left and right side members and front and rear cross members is attached to the left and right front frames at the four front, rear, left and right corners. Those have also been commonly used in the past.

[0004]

As described above, in the conventional structure in which the subframe is directly fixed to the front frame, at the time of a frontal collision, the subframe is affected by the deformation of the front frame at the initial stage of the collision, and the front frame is also affected. When the buckling deformation occurs, the sub-frame also buckles and deforms together with the front frame even if there is no collision load input directly from the barrier to the sub-frame. As a result, the initial resistance of the frame to the collision load is improved, but the degree of freedom in tuning the collision performance of the frame as a single unit is reduced.

In the conventional structure in which the subframe on which the power unit is mounted is fixed to the front frame as described above, it is necessary to completely separate the subframe from the front frame when attaching and detaching the engine and the transmission. In addition, there is also a problem that a great deal of time and trouble are required for the maintenance work of the power unit.

An object of the present invention is to address the above-mentioned conventional problems.

[0007]

According to the present invention, the left and right front portions of a power unit mounting sub-frame are rotatably mounted below the left and right front frames via arm members, respectively. Since the parts are fixed to the left and right front frames, the mounting part via the arm member rotates even if the front frame buckles and deforms due to the collision load in the event of a frontal collision of the vehicle. The frame is less susceptible to buckling deformation of the front frame,
The degree of freedom in tuning the collision performance of the frame alone can be increased.

Further, by removing the mounting portion of the rear portion of the sub-frame to the front frame, the sub-frame can be rotated downward about the mounting portion of the front portion, so that the power mounted on the sub-frame can be reduced. The unit can be detached and attached without completely separating the subframe from the vehicle body, and the workability of the maintenance of the power unit can be significantly improved.

Further, the arm member for suspending the front portion of the sub-frame is extended downward to form a tie-down hook, so that the vehicle body can be securely held when the tie-down hook is used, and the number of parts is reduced. be able to.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numerals 1, 1 denote left and right front frames having a closed cross section which are disposed in the front-rear direction along left and right side walls of an engine room at a front part of a vehicle body. A front bumper 2 is attached to the front end, and in the event of a frontal collision, a collision load is input to the front frames 1 and 1 via the front bumper 2 and the front frames 1 and 1 buckle and deform, thereby reducing collision energy. It performs absorption.

Reference numeral 3 denotes a sub-frame. The sub-frame 3 has a substantially cross-girder shape including a front side 4 serving as a front cross member, left and right side parts 5, 5 and a rear engine cross member 6. You. Front part 4, side part 5, and engine cross member 6 which are components of the sub-frame 3
Are each constituted by a closed section member.

The sub-frame 3 is rotatably mounted at the front portions of the side portions 5 and 5 to the left and right front frames 1 and 1 via tie-down hook members 7 and 7 with bolts 8a and 8b. The left and right portions of the engine cross member 6 are fixed to the left and right front frames 1, 1 with bolts, nuts, and the like, and are disposed and supported below the front frames 1, 1. A power unit 9 such as an engine and a transmission is mounted on the sub-frame 3, and one end 10 a of a lower arm 10 of the front suspension is also mounted and supported on the rear end of the side 5 of the sub-frame 3. The other end 10 of the lower arm 10
b is mounted and supported on the vehicle body (the front frame 1) at a position behind the side portion 5.

The tie-down hook member 7 is rotatably mounted on the front frame 1 with a single bolt 8a, and is attached to the side frame 5 of the sub-frame 3 with two bolts 8b, 8b. It is fastened and fixed at two places in the horizontal direction.

As described above, the front portions of the left and right side portions 5 are axially attached to the left and right front frames 1 by the right and left tie-down hook members 7 and the engine cross members 6 are provided.
The left and right portions are fixed to the left and right front frames 1 and the sub frame 3 is attached to the front frame 1, so that the sub frame 3 is firmly fixed to the front frame 1 in a normal state, and the tie-down hook Also, the body holding load applied to the tie-down hook member 7 during use is firmly supported by the sub-frame 3 and the front frame 1, and the body can be securely held.

When a frontal collision of the vehicle occurs, as shown in FIG. 2, when the front frame 1 buckles and deforms due to a collision load, the connection point of the tie-down hook member 7 to the front frame 1 is displaced rearward. The connection point of the tie-down hook member 7 to the front frame 1 is a single bolt 8a.
The tie-down hook member 7 is slightly bent by the input large load and the side portion 5 of the sub-frame 3 is relatively bent with respect to the front frame 1 around the bolt 8a. The front frame 1 is rotated forward, so that the buckling deformation of the front frame 1 is less likely to be transmitted to the subframe 3, and the degree of freedom to shift the timing of starting the buckling deformation of the front frame 1 and the subframe 3 is increased.
Tuning of the collision performance by changing the position, cross-sectional area, etc. of the vehicle becomes easy.

When the connecting portion between the engine cross member 6 and the front frame 1 at the rear of the sub frame 3 is removed, the sub frame 3 is connected to the tie-down hook member 7 and the front frame 1 as shown in FIG. Bolt 8
Since it can be rotated downward around the center a, the transmission and the like can be attached and detached without completely separating the sub-frame 3 from the vehicle body (the front frame 1), and the maintenance of the power unit 9 is very easy. Becomes

In the illustrated embodiment, the connecting portion of the tie-down hook member 7 to the front frame 1 is connected to one bolt 8a.
In this example, the tie-down hook member 7 is connected to the front frame 1 by two bolts, and the tie-down hook member 7 is fixed to the front frame 1 by two bolts. May be connected to the side portion 5 by a single bolt. In such a case, when the front frame 1 is buckled by the collision load and the tie-down hook member 7 is displaced rearward, The tie-down hook member 7 rotates relatively to the side 5 of the frame 3 to bend and deform the side 5. Further, both the connecting portion of the tie-down hook member 7 to the front frame 1 and the connecting portion to the side portion 5 may be respectively attached to the shaft by one bolt. Buckling deformation of the sub-frame 3 can be minimized.

Further, as in the above embodiment, a tie-down hook member 7 is used as an arm member for suspending and supporting the front portion of the sub-frame 3 below the front frame 1 so as to be rotatable.
By using the tie-down hook member, the function as a support member for the sub-frame can also be used, and the number of parts can be reduced and the cost can be reduced. This is extremely effective. A simple arm member may be used in place of the down hook member, and a tie down hook member may be used as a structure in which the front portion of the sub-frame 3 is rotatably suspended below the front frame 1 by the arm member. Almost the same operation and effect as in the case of using can be obtained.

[0020]

As described above, according to the present invention, in the front body structure of a vehicle in which the front part and the rear part of the subframe are attached to the left and right body members, that is, the left and right front frames, When the front frame of the vehicle is crushed by a collision load, the arm is attached to the front frame so that the arm is rotatably mounted via the arm member. Since the mounting portion is rotated via the member, the sub-frame is hardly affected by the buckling deformation of the front frame, and the degree of freedom in tuning the collision performance as a single frame can be increased. If a tie-down hook member is used, the tie-down hook member can also be used to fasten the function of fastening the front frame and the subframe. Member is no longer required, the number of parts,
Associate costs, costs, etc. can be reduced.

Further, when the mounting portion of the rear portion of the sub-frame to the front frame is removed, the sub-frame can be rotated downward about the mounting portion of the front portion of the sub-frame. The attachment / detachment work can be performed without completely detaching the subframe from the vehicle body, and the workability of maintenance of the power unit can be significantly improved.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention.
(A) is an explanatory plan view showing an outline of the arrangement position of the subframe, and (B) is an explanatory side view of (A).

FIG. 2 is an explanatory side view for explaining a vehicle body deformation mode at the time of a frontal collision in a vehicle equipped with the subframe shown in FIG. 1;

3 is an explanatory side view illustrating a maintenance operation mode of a power unit in a vehicle equipped with the subframe shown in FIG. 1;

[Description of Signs] 1 Front frame 2 Front bumper 3 Subframe 4 Front side 5 Side side 6 Engine cross member 7 Tie down hook member 8 Bolt 9 Power unit 10 Lower arm

Claims (3)

[Claims] 1. A left and right front portion of a mounting sub-frame for a power unit is rotatably mounted below left and right front frames via arm members, and the left and right rear portions of the sub-frame are attached to the left and right front frames. A front body structure of a vehicle, which is fixed. 2. The front body structure of a vehicle according to claim 1, wherein one or both of a mounting portion of the arm member to the front frame and a mounting portion of the arm member to the subframe are formed by a single bolt. A front vehicle body structure of a vehicle, wherein the vehicle body structure is a wearing structure. 3. The front body structure of a vehicle according to claim 1, wherein the arm member extends below the subframe, and an engagement hole is provided at a tip portion thereof to form a tie-down hook. A front body structure of a vehicle, characterized by: