JP2001310756A - Vehicle body front part structure for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle body front part structure improving supporting rigidity of a suspension and securing a shock energy absorbing function based on a subframe. SOLUTION: A suspension cross member 20 is arranged across between left and right side frames 11, 12 extending in the vehicle body longitudinal direction, while a side frame 40 connected to the lower parts of the side frames 11, 12 via left and right vertical frames 41, 42 and a lateral frame 43 is arranged, and the front and back parts of the suspension cross member 20 and the vertical frames 41, 42 are connected mutually by means of a front part supporting bracket 31 and a back part supporting bracket 34. A stabilizer mounting part is arranged in the front part supporting bracket 31, while a mounting part for a lower arm bush 51 supporting a suspension lower arm 50 is arranged in the back part supporting bracket 34.

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, and more particularly to a vehicle body in which a suspension cross member is provided between left and right side frames and a subframe is provided below the side frames. Regarding the front structure.

[0002]

2. Description of the Related Art The front part of an automobile is disclosed, for example, in JP-A-7-61.
No. 243, and a pair of side frames 101 extending in the front-rear direction along both sides of the vehicle body as shown in FIG. The suspension lower member 103 (only one of which is shown) is swingably supported at lower portions on both sides of the suspension cross member 102, and is mounted on the suspension cross member 102. Power units (not shown) such as an engine and a transmission are mounted via members 104 and the like.

As shown in the perspective view of the main part of FIG. 5, a left and right vertical frame 106 extending forward and backward along a side frame 101 is provided at the front of the vehicle. The front horizontal frame 107 and the rear horizontal frame 1 erected between the front end and the rear end so as to extend in the vehicle width direction, respectively.
08 to the side frame 10
1, there is a front structure of a motor vehicle that generates an effective impact energy absorbing function against an input of an impact load from the front.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 7-612.
According to Japanese Patent No. 43, the suspension lower arm 10 can simply swing freely on a suspension cross member 102 that is installed to project downward from the left and right side frames 101.
3, the lower suspension arm 1
The support rigidity of the suspension lower arm 03 cannot be sufficiently secured, and the vehicle is steered by a lateral force or a drag input from a wheel supported on the outer end of the suspension lower arm 103 and a vertical load repeatedly input during turning, driving, braking, and the like. In addition to causing a decrease in stability, there is a concern about the occurrence of road noise.

As a countermeasure, it is conceivable to increase the thickness of the suspension cross member 102 or to add a reinforcing member in order to secure the rigidity of the suspension cross member 102, but this causes a complicated structure and an increase in the weight of the vehicle body.

On the other hand, as shown in FIG.
When a large impact load is applied from the front of the sub-frame 105 to the body where the sub-frame 105 is disposed below the sub-frame 01, a sufficient impact energy absorbing function is achieved by buckling deformation at the intermediate portion of the vertical frame 106. It is feared that it will not be.

[0007] An object of the present invention is to focus on such a point, thereby improving the support rigidity of the suspension and ensuring the impact energy absorbing function of the subframe without increasing the complexity of the structure and the weight of the vehicle body. Is to provide.

[0008]

According to a first aspect of the present invention, there is provided a vehicle body front structure in which a suspension cross member is bridged between left and right side frames extending in the vehicle longitudinal direction. And left and right vertical frames extending in the front-rear direction below the left and right side frames and having rear ends coupled to the side frames, and a horizontal frame connecting front portions of the two vertical frames. In a vehicle body front structure provided with a sub-frame, a support bracket having a lower arm bush mounting portion for connecting the suspension cross member and a vertical frame of the sub-frame is provided.

According to the first aspect of the present invention, the lower arm bush mounting portion is formed on the supporting bracket which is secured between the suspension frame member connected to the side frame and the vertical frame of the sub-frame to ensure rigidity. The support rigidity of the suspension lower arm supported by the bush is secured, the support rigidity of the suspension is improved, and the running stability is improved.

On the other hand, the suspension frame member connected to the vertical frame and the side frame of the sub-frame is connected by the support bracket, so that the sub-frame is supported by the side frame and the resistance of the sub-frame to the impact load from the front is secured. As a result, the impact energy absorbing function is improved.

According to a second aspect of the present invention, in the vehicle body front structure according to the first aspect, the support bracket includes the lower arm bush mounting portion at a position close to a coupling portion with the vertical frame. Features.

According to the second aspect of the present invention, the lower arm bush mounting portion is disposed near the connecting portion between the vertical frame and the support bracket which can obtain particularly rigidity, so that the support rigidity of the lower arm bush is further improved, and the suspension of the suspension is improved. The support stiffness is further improved, and the running stability is further improved.

According to a third aspect of the present invention, in the vehicle body front structure according to the first or second aspect, the support bracket has an upper portion connected to a front portion of the suspension cross member and a lower end connected to the vertical frame. And a rear support bracket having an upper portion connected to a rear portion of the suspension cross member and a lower end connected to the vertical frame.

According to the third aspect of the present invention, the upper portion of the front support bracket and the upper portion of the rear bracket are respectively connected to the front and rear portions of the suspension cross member.
Since the lower end of each support bracket is connected to each vertical frame of the sub-frame, the rigidity of the suspension cross member is increased, and the longitudinal swing caused by the input load from the suspension lower arm is reduced, resulting in quietness and comfort. The property can be improved.

According to a fourth aspect of the present invention, in the vehicle body front structure according to the third aspect, the suspension cross member is formed to be bent downward along an upper surface and a front edge and a rear edge of the upper surface. The vehicle has a substantially U-shaped cross section extending in the vehicle width direction including a front flange and a rear flange, an upper end of the front support bracket is coupled to the front flange, and an upper end of the rear support bracket is It is characterized by being connected to the rear flange.

According to the present invention, the upper portions of the front support bracket and the rear bracket are respectively connected to the front flange and the rear flange of the suspension cross member, and the lower end of each support bracket is connected to each of the subframes. The rigidity of the suspension cross member formed into a U-shaped cross section is increased by being connected to the vertical frame, the natural frequency in the front-rear direction is increased, and the load noise due to the input load from the suspension lower arm is reduced. Noise and vibration are suppressed.

According to a fifth aspect of the present invention, in the front body structure of an automobile according to the third or fourth aspect, the front support bracket has a stabilizer fixing portion, and the rear support bracket has a lower arm bush mounting. It is characterized by having a part.

According to the fifth aspect, since the front support bracket is provided with the stabilizer fixing portion and the rear support bracket is provided with the lower arm bush mounting portion, the front support bracket and the rear support bracket have a front support bracket mounting function and a lower arm. A bush mounting function is provided, and simplification of the configuration is provided.

According to a sixth aspect of the present invention, in the vehicle front body structure according to any one of the first to fifth aspects, the lower end of the support bracket is located at or near the shape change point of the vertical frame. It is characterized by being bound to a site.

According to the sixth aspect, the lower end of the support bracket is connected to the shape change point at or near the discontinuity in the rigidity of the vertical frame to support the sub-frame, so that the sub-frame against the impact load from the front is supported. The drag of the frame is secured, and the impact energy absorbing function is secured.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a front body structure of an automobile according to the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of an essential part showing an outline of the present embodiment, FIG. 2 is an enlarged view of a part A in FIG. 1, and an arrow F indicates a forward direction of the vehicle body.

In the figure, reference numerals 11 and 12 denote side frames extending in the front-rear direction along the left and right side walls of the engine room, that is, between the left and right side frames 11 and 12 in the vehicle width direction. Existing Spence Cross Member 20
And a sub-frame 40 is provided below the side frames 11 and 12.

The right and left ends of the upper surface 21 of the suspension cross member 20 are respectively left and right side frames 11 and 12.
Is fixed to the lower surface of the upper surface 21 with bolts and nuts (not shown), and the front flange 22 extends along the front and rear edges of the upper surface 21.
The rear flange 23 is bent downward and has a substantially U-shaped cross-section that is continuous in the vehicle width direction and is open at the bottom, and is bent downward at both left and right edges of the upper surface 21 to form front and rear ends. Side flanges 24 are formed at the side ends of the front flange 22 and the rear flange 23, respectively.

The upper surface 2 of the suspension cross member 20
1, a power unit (not shown) is supported, seat surfaces 25 for mounting an engine mount for isolating vibrations from the power unit are provided on the left and right sides, and the inside of the suspension cross member 20, that is, the lower side of the upper surface 21. A steering gear box (not shown) is mounted along a vehicle width direction via a bracket.

Further, a front support bracket 31 is provided near the rear surface of the front flange 22 of the suspension cross member 20, that is, near the side end of the rear surface of the vehicle body, and protrudes downward. That is, the rear support bracket 34 is mounted to protrude downward near the side end of the front surface of the vehicle body.

The front support bracket 31 has a stabilizer 47 for controlling the rolling of the vehicle body by connecting the left and right suspension lower arms 50 via stabilizer links 48, and is fixed to the lower end side of the front support bracket 31. Lower surface 32a and side surfaces 32b, 32c
A sub-frame connecting bracket 32 having a U-shaped cross section and extending in the front-rear direction is welded, and a welding nut 33 is attached to the lower surface 32a.

On the other hand, the rear support bracket 34 is attached to the front surface of the rear flange 23 and protrudes downward, and the front support bracket 34 is attached to the upper surface 21 and is substantially parallel to the rear bracket 35 and protrudes downward. Bracket 3
6.

Rear bracket 35 and front bracket 36
A lower arm bush 51 supporting the front base end 50a of the suspension lower arm 50 is fitted between the lower end portion and the vicinity of the lower end of the suspension arm 50 with a shaft extending in the front-rear direction, and a bolt 52 and a nut penetrating the lower arm bush 51 in the front-rear direction. 5
3, the front base end 50a of the suspension lower arm 50 is swingably supported by being supported by the rear bracket 35 and the front bracket 36, and the rear end 50b of the suspension lower arm 50 is connected to a body member by a bush (not shown) or the like. And is rotatably supported via.

Further, a sub-frame connecting bracket 37 is welded to a lower end of the rear bracket 35, and a welding nut 38 is attached to the sub-frame connecting bracket 37.

The sub-frame 40 has left and right vertical frames 41 and 42 whose rear ends are respectively coupled to the lower surfaces of the left and right side frames 11 and 12 and extends in the front-rear direction. It has a horizontal frame 43 connecting the front ends of the vertical frames 41 and 42, and the vertical frames 41 and 42 are bent portions due to layout restrictions such as suspensions and power units, that is, shape changing points 4 where the shape changes.
1a, 41b and 42a, 42b are formed.

The shape change points 41a and 42a or the vicinity thereof are respectively connected to the lower surface 32a of the sub-frame connection bracket 32 provided at the lower ends of the left and right front support brackets 31.
Attaching from below with a mounting bolt (not shown) that is screwed into the welding nut 33,
The shape change points 41b, 42b or the vicinity thereof abut from below on the lower surface of the sub-frame connection bracket 37 provided at the lower end of the rear bracket 35 on the left and right rear support brackets 34 and are screwed into the welding nut 38. By mounting with the mounting bolts (not shown), the intermediate portions of the vertical frames 41 and 42 are connected to the suspension cross member 20 by the front support bracket 31 and the rear support bracket 34.

According to the vehicle body front structure constructed as described above, the lower arm bush 51 for swingably supporting the front base end 50a of the suspension lower arm 50 is connected to the suspension cross member fixed to the side frames 11, 12. Since the rear support bracket 35 erected between the sub-frame 20 and the sub-frame 40 is attached to a portion where the rigidity is secured in close proximity to the joint with the sub-frame 40, the support rigidity of the lower arm bush 51 is secured, Sufficient mounting support rigidity of the suspension lower arm 50 supported by the lower arm bush 51 is obtained.

Therefore, when the vehicle is turning, driving, braking, or the like, the vehicle is caused by lateral force or longitudinal force input from wheels supported on the outer end 50c of the suspension lower arm 50, and vertical loads repeatedly input. A decrease in steering stability is avoided, and steering stability is ensured.

The upper end of the front support bracket 31 and the upper end of the rear bracket 34 are respectively connected to the front flange 22 and the rear flange 23 of the suspension cross member 20.
And the lower ends of the support brackets 31 and 34 are connected to the vertical frames 41 and 42 of the sub-frame 40, respectively, so that the rigidity of the suspension cross member 20 formed in a U-shaped cross section increases and The natural frequency in the direction is increased, and the longitudinal vibration caused by the input load from the suspension lower arm 50, that is, the road noise is reduced, so that noise and vibration are suppressed, and quietness and comfort are improved. .

On the other hand, if the sub-frame 40 is not connected to the front and rear support brackets 31 and 34, an impact load is applied to the horizontal frame 43 of the sub-frame 40 from the front as shown in FIG. When P1 acts, buckling deformation occurs relatively easily at the shape change points 41a, 41b and 42a, 42b of the vertical frames 41, 42 of the sub-frame 40, and no impact drag can be obtained. As shown by the solid line in FIG. 3, the G waveform (energy absorption waveform) suddenly increases from the initial stage of the collision, and tends to sharply decrease after the peak, and there is concern that sufficient absorption of impact energy may not be achieved.

However, according to the present embodiment, the shape change points 41a, 41b and 42 of the vertical frames 41 and 42 respectively.
a, 42b or the vicinity of these change points are supported by the front support bracket 31 and the rear support bracket 34, so that buckling deformation at the shape change points 41a, 41b and 42a, 42b is suppressed, and a resistance to an impact load is generated. The shock energy absorption characteristic gradually increases from the initial stage of the collision as shown by the broken line in FIG. 3 and continues after the peak, and the pick value is suppressed to ensure sufficient absorption of the shock energy. Is done.

In a state where the sub-frame 40 is not joined to the front support bracket 31 and the rear support bracket 34, as shown in FIG. P2, for example, when the impact load P2 is offset and acts on the driver's seat side, it is mainly input to the vertical frame 42 on the driver's seat side, and the change points 42a and 42b of the vertical frame 42 on the driver's seat side buckle relatively easily. It deforms, and its G waveform rapidly increases from the beginning of the collision, and tends to rapidly decrease after the peak, and there is a concern that effective impact energy absorption may not be achieved.

However, according to the present embodiment, the shape change points 42a and 42b of the vertical frame 42 or the vicinity thereof and the change points 41a and 41 of the other vertical frame 41 are changed.
b or the vicinity thereof are connected to each other by the suspension cross member 20, the front support bracket 31, and the rear bracket 34, so that the left and right vertical frames 41 and 42 can be integrated, for example, offset to the driver's seat side. When the impact load P2 is applied, the impact load P2 is dispersedly transmitted from the left vertical frame 42 to the other vertical frame 41, that is, the vertical frame 41 on the passenger seat side via the suspension cross member 20 and the like. As a result, the G waveform of the impact energy absorption characteristics of the left and right vertical frames 41 and 42 gradually increases from the beginning of the collision, continues after the peak, and the peak value is suppressed to sufficiently absorb the impact energy. Is secured.

A front support bracket 31 for connecting the suspension cross member 20 and the subframe 40 is also provided.
Is also a structure for attaching the stabilizer, and the lower end of the rear support bracket 34 supporting the lower arm bush 51 is connected to the sub-frame 40. The increase in the support rigidity of the suspension and the impact energy by the sub-frame are ensured without increasing the vehicle body weight and the manufacturing cost.

The present invention is not limited to the above embodiment, but can be variously modified without departing from the spirit of the invention. For example, the suspension cross member 20 and the front support bracket 31 and the rear support bracket 34 can be integrally formed.
4 is connected to the side frame 40 by connecting the lower end of the front bracket 36 to the side frame 40 and the lower arm bush 5.
It is also possible to further increase the support rigidity of 1 or further add a support bracket for connecting the suspension cross member 20 and the side frame 40 between the front bracket 31 and the rear support bracket 34.

[0042]

According to the front structure of the vehicle body of the present invention described above, the lower arm bush mounting portion is provided on the suspension bracket which is connected to the side frame and the support bracket which is erected on the vertical frame of the sub-frame to ensure rigidity. The suspension rigidity of the suspension lower arm formed and supported by the lower arm bush is ensured, the support rigidity of the suspension is improved, the steering stability is improved, and the suspension clamp connected to the vertical frame and the side frame of the sub-frame is provided. Since the members are connected by the support brackets, the sub-frame is supported by the side frame, the drag of the sub-frame against the impact load from the front is secured, the impact energy absorbing function is secured, and this structure is relatively simple. Ensure that the weight of the vehicle does not increase When the one in which together made large to contribute to the automobile manufacturing industry.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is an explanatory diagram of impact energy absorption characteristics.

FIG. 4 is a perspective view of an essential part showing an outline of a conventional vehicle body front structure.

FIG. 5 is a perspective view of an essential part showing an outline of a conventional body front structure.

[Explanation of symbols]

 11, 12 Side frame 20 Suspension cross member 21 Top surface 22 Front flange 23 Rear flange 31 Front support bracket 32 Bracket for subframe connection 34 Rear support bracket 35 Rear bracket 36 Front bracket 37 Bracket for subframe connection 41, 42 Vertical Frame 41a, 41b, 42a, 42b Shape change point 43 Horizontal frame 47 Stabilizer 50 Suspension lower arm 51 Lower arm bush

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuichi Kuroda 1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji Heavy Industries Ltd. F-term (reference) 3D001 AA17 BA01 CA01 DA08 DA11 3D003 AA01 AA05 BB02 CA09 CA18 CA53 DA29

Claims (6)

[Claims] 1. A suspension cross member spans and is coupled between left and right side frames extending in the vehicle longitudinal direction, and extends in the longitudinal direction below the left and right side frames and has a rear end. In a vehicle body front structure including a left and right vertical frame coupled to the side frame and a subframe having a horizontal frame connecting front portions of the two vertical frames, the suspension cross member and the vertical frame of the subframe are provided. And a support bracket having a lower arm bush mounting portion. 2. The vehicle body front structure according to claim 1, wherein the support bracket includes the lower arm bush mounting portion at a position close to a coupling portion with a vertical frame. 3. The support bracket has an upper portion connected to a front portion of the suspension cross member and a lower end connected to the vertical frame, and an upper portion connected to a rear portion of the suspension cross member and a lower end. A rear support bracket coupled to said vertical frame.
2. The vehicle body front structure according to claim 1. 4. The suspension cross member includes an upper surface, and a front cross-section extending in a vehicle width direction having a front flange and a rear flange bent downward along respective front and rear edges of the upper surface. The motor vehicle according to claim 3, wherein the upper portion of the front support bracket is connected to the front flange, and the upper portion of the rear support bracket is connected to the rear flange. Body front structure. 5. The front vehicle body structure according to claim 3, wherein the front support bracket includes a stabilizer fixing portion, and the rear support bracket includes a lower arm bush mounting portion. . 6. The front of a vehicle according to claim 1, wherein a lower end of the support bracket is connected to a shape changing point of the vertical frame or a portion near the shape changing point. Body structure.