JP4739481B2 - Auto body front structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile body front structure, and more particularly to an automobile body front structure in which a suspension cross member is installed between left and right side frames and a subframe is disposed below the side frames.
[0002]
[Prior art]
A front portion of the automobile is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-61243, and a pair of side frames 101 extending in the front-rear direction along both sides of the vehicle body are disposed as shown in a perspective view of a main part in FIG. The suspension cross member 102 is provided with both ends joined to the left and right side frames 101 so as to extend in the vehicle width direction, and a suspension lower arm 103 (only one is shown) is swingable at both lower portions of the suspension cross member 102. The suspension cross member 102 is mounted with a power unit (not shown) such as an engine and a transmission via a mount member 104 and the like.
[0003]
Further, as shown in the perspective view of the main part in FIG. 5, the front part of the automobile has left and right vertical frames 106 extending forward and backward along the lower side of the side frame 101, and the front ends of the left and right vertical frames 106 By inputting a sub-frame 105 having a front horizontal frame 107 and a rear horizontal frame 108 extending in the vehicle width direction between the rear ends below the side frames 101, an impact load from the front can be input. There is a front structure of an automobile that generates an effective impact energy absorbing function.
[0004]
[Problems to be solved by the invention]
According to Japanese Patent Laid-Open No. 7-61243, the suspension lower arm 103 is supported by the suspension cross member 102 that protrudes downward from the left and right side frames 101 and is swingable. Steering stability is reduced due to lateral force and drag input from the wheel supported at the outer tip of the suspension lower arm 103 during turning, driving and braking, and repeated vertical load In addition, there is a concern about the generation of road noise.
[0005]
As measures against this, an increase in the plate thickness or the addition of a reinforcing member can be considered in order to ensure the rigidity of the suspension cross member 102, but this causes a complicated structure and an increase in the weight of the vehicle body.
[0006]
On the other hand, in the vehicle body in which the subframe 105 is disposed below the side frame 101 as shown in FIG. 5, when an excessive impact load is applied from the front of the subframe 105, buckling deformation occurs in the middle portion of the vertical frame 106. Then, there is a concern that a sufficient impact energy absorbing function cannot be achieved.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle body front structure in which the support rigidity of a suspension is improved and an impact energy absorbing function is secured by a subframe without incurring the complexity of the structure and the weight of the vehicle body by paying attention to such points. There is.
[0008]
[Means for Solving the Problems]
The invention of the front vehicle body structure of the vehicle according to claim 1 that achieves the above object is characterized in that a suspension cross member is spanned and coupled between the left and right side frames extending in the longitudinal direction of the vehicle body, and A vehicle body including a left and right vertical frame extending in the front-rear direction below the side frame and having a rear frame coupled to the side frame and a subframe having a horizontal frame connecting the front portions of the two vertical frames. The front structure includes a support bracket that connects the suspension cross member and the vertical frame of the sub-frame and has a lower arm bush mounting portion.
[0009]
According to the first aspect of the present invention, the lower arm bushing mounting portion is formed on the support bracket that is installed between the suspension cross member coupled to the side frame and the vertical frame of the subframe to ensure rigidity, and is supported by the lower arm bush. The suspension rigidity of the suspension lower arm to be secured is ensured, and the suspension support rigidity is improved, and the running stability is improved.
[0010]
On the other hand, since the suspension cross member coupled to the vertical frame of the sub frame and the side frame is connected by the support bracket, the sub frame is supported by the side frame, and the resistance of the sub frame against the impact load from the front is ensured and the impact is achieved. Energy absorption function is improved.
[0011]
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 portion close to the coupling portion with the vertical frame. .
[0012]
According to the second aspect of the present invention, the lower arm bush mounting portion is disposed in the vicinity of the connecting portion between the vertical frame and the support bracket, in particular, where rigidity and strength are obtained, so that the support rigidity of the lower arm bush is further improved, and the suspension support rigidity is increased. This further improves the running stability.
[0013]
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 includes a front portion coupled to a front portion of the suspension cross member and a lower end coupled to the vertical frame. And a rear support bracket having an upper portion coupled to a rear portion of the suspension cross member and a lower end coupled to the vertical frame.
[0014]
According to the invention of claim 3, the upper part of the front support bracket and the upper part of the rear bracket are coupled to the front part and the rear part of the suspension cross member, respectively, and the lower end of each support bracket is coupled to each vertical frame of the subframe. As a result, the rigidity of the suspension cross member is increased, and the vibration in the front-rear direction caused by the input load from the suspension lower arm is reduced, thereby improving the quietness and the comfort.
[0015]
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 by bending the upper surface and a front flange formed respectively downward along the front edge and the rear edge of the upper surface. The rear support bracket has a substantially U-shaped cross section extending in the vehicle width direction, the upper end of the front support bracket is coupled to the front flange, and the upper end of the rear support bracket is the rear flange. It is characterized by being coupled to.
[0016]
According to the invention of claim 4, the upper portions of the front support bracket and the rear bracket are coupled to the front flange and the rear flange of the suspension cross member, respectively, and the lower ends of the support brackets are respectively connected to the vertical frames of the subframe. As a result of the coupling, the rigidity of the suspension cross member having a U-shaped cross section is increased, the natural frequency in the front-rear direction is increased, and a reduction in road noise caused by an input load from the suspension lower arm is brought about. Vibration is suppressed.
[0017]
According to a fifth aspect of the present invention, in the front vehicle body structure of the automobile according to the third or fourth aspect, the front support bracket includes a stabilizer fixing portion, and the rear support bracket includes a lower arm bush mounting portion. It is characterized by that.
[0018]
According to the fifth aspect, the front support bracket includes the stabilizer fixing portion, and the rear support bracket includes the lower arm bush mounting portion. Therefore, the front support bracket and the rear support bracket include the stabilizer mounting function and the lower arm bush mounting function, respectively. Simplification of the configuration is brought about.
[0019]
According to a sixth aspect of the present invention, in the front body structure of the automobile according to any one of the first to fifth aspects, the lower end of the support bracket is coupled to a shape change point of the vertical frame or a vicinity of the shape change point. It is characterized by that.
[0020]
According to the sixth aspect of the present invention, since the lower end of the support bracket is coupled to the shape change point where the vertical frame is discontinuous or the vicinity thereof to support the subframe, the resistance of the subframe to the impact load from the front is supported. Is secured and the impact energy absorbing function is secured.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a front body structure of an automobile according to the present invention will be described with reference to FIGS.
[0022]
FIG. 1 is a main part perspective view 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 vehicle body front direction.
[0023]
In the figure, 11 and 12 are side frames extending in the front-rear direction along the left and right side walls of the vehicle body, that is, the left and right side frames of the engine room. A pension cross member 20 is installed and a subframe 40 is disposed below the side frames 11 and 12.
[0024]
The suspension cross member 20 has left and right ends of the upper surface 21 fixed to the lower surfaces of the left and right side frames 11 and 12 by bolts and nuts (not shown), and a front flange 22 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 with the lower portion continuous in the vehicle width direction opened, and is bent downward at both left and right edges of the upper surface 21 so that the front end and the rear end are Side flanges 24 that are continuous to the side ends of the front flange 22 and the rear flange 23 are formed.
[0025]
Supporting a power unit (not shown) on the upper surface 21 of the suspension cross member 20, seat surfaces 25 for mounting an engine mount that blocks vibration from the power unit are provided on the left and right sides, and the inside of the suspension cross member 20. That is, a steering gear box (not shown) is attached to the lower side of the upper surface 21 along the vehicle width direction via a bracket.
[0026]
Further, a front support bracket 31 that is attached to 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, is provided, and the front surface of the rear flange 23, that is, the front surface of the vehicle body. A rear support bracket 34 is attached so as to protrude downward in the vicinity of the side end of the side surface.
[0027]
The front support bracket 31 has a stabilizer 47 for controlling rolling of the vehicle body by connecting the left and right suspension lower arms 50 via a stabilizer link 48, and a lower surface 32a and a lower end side portion of the front support bracket 31. A subframe connecting bracket 32 having a U-shaped cross section having side surfaces 32b and 32c and extending in the front-rear direction is welded, and a welding nut 33 is attached to the lower surface 32a. In this way, a stabilizer fixing portion for fixing the stabilizer 47 to the front support bracket 31 is formed.
[0028]
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 bracket 36 is attached to the upper surface 21 and is substantially parallel to the rear bracket 35 and protrudes downward. have.
[0029]
A lower arm bush 51 that supports the front base end 50a of the suspension lower arm 50 is fitted between the lower bracket portions of the rear bracket 35 and the front bracket 36 so that the shaft extends in the front-rear direction. By supporting the rear bracket 35 and the front bracket 36 with bolts 52 and nuts 53 penetrating in the direction, the front end base 50a of the suspension arm lower 50 is swingably supported, and the rear end 50b of the suspension lower arm 50 is supported by the vehicle body member. It is rotatably supported via a bush (not shown) or the like. A position near the lower end of the rear bracket 35 and the front bracket 36 that supports the lower arm bush 51 with bolts 52 and nuts 53 is a lower arm bush mounting portion.
[0030]
Further, a subframe connection bracket 37 is welded to the lower end of the rear bracket 35, and a welding nut 38 is attached to the subframe connection bracket 37.
[0031]
The sub frame 40 has rear ends coupled to the lower surfaces of the left and right side frames 11 and 12, respectively, and left and right vertical frames 41 and 42 extending in the front-rear direction, and a left and right vertical frame 41 extending in the vehicle width direction. And vertical frames 41 and 42 are bent portions that are bent due to layout restrictions such as suspensions and power units, that is, shape change points 41a, 41b and 42a, 42b where the shapes change. Is formed.
[0032]
The mounting bolts that come into contact with 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 from below and are screwed into the welding nut 33 at the shape change points 41a and 42a or in the vicinity thereof. (Not shown), and the shape change points 41b, 42b or adjacent portions are brought into contact with the lower surface of the subframe connection bracket 37 provided at the lower end of the rear bracket 35 of the left and right rear support brackets 34 from below. By attaching with a mounting bolt (not shown) screwed to the welding nut 38, the intermediate portions of the vertical frames 41, 42 are coupled to the suspension cross member 20 by the front support bracket 31 and the rear support bracket 34.
[0033]
According to the vehicle body front structure configured as described above, the lower arm bush 51 that swingably supports the front base end 50a of the suspension lower arm 50 includes the suspension cross member 20 fixed to the side frames 11 and 12 and the sub-cross member 20. Since the rear support bracket 34 installed on the frame 40 is attached to a portion where the rigidity is secured in the vicinity of the joint portion with the sub frame 40, the support rigidity of the lower arm bush 51 is secured, and the lower arm bush 51 is secured. Thus, a sufficient mounting rigidity of the suspension lower arm 50 supported by the above can be obtained.
[0034]
Accordingly, steering stability due to lateral force and longitudinal force input from the wheel supported on the outer tip 50c of the suspension lower arm 50 during turning, driving, braking, etc. during traveling, and vertical load input repeatedly. Is prevented, and steering stability is ensured.
[0035]
Further, the upper ends of the front support brackets 31 and the upper portions of the rear brackets 34 are coupled to the front flange 22 and the rear flange 23 of the suspension cross member 20, respectively, and the lower ends of the support brackets 31 and 34 are respectively connected to the subframe 40. Since the suspension cross member 20 having a U-shaped cross section is connected to each of the vertical frames 41 and 42, the rigidity of the suspension cross member 20 is increased and the natural frequency in the front-rear direction is increased. The vibration of the direction, that is, the reduction of road noise is brought about, and the noise and vibration are suppressed, so that the quietness and the comfort are improved.
[0036]
On the other hand, if the subframe 40 is not coupled to the front and rear support brackets 31 and 34, for example, due to a frontal collision, an impact load P1 is applied to the horizontal frame 43 of the subframe 40 from the front as shown in FIG. Then, the shape change points 41a, 41b and 42a, 42b of the vertical frames 41, 42 of the sub-frame 40 can be buckled and deformed relatively easily, and impact resistance cannot be obtained. As indicated by the solid line, the waveform (energy absorption waveform) increases rapidly from the beginning of the collision and tends to decrease rapidly after the peak, and there is a concern that sufficient impact energy absorption cannot be achieved.
[0037]
However, according to the present embodiment, the shape change points 41a, 41b and 42a, 42b of the vertical frames 41, 42 or the vicinity of these change points are supported by the front support bracket 31 and the rear support bracket 34, and the shape changes. Buckling deformation at the points 41a, 41b and 42a, 42b is suppressed to generate a drag force against the impact load, and the impact energy absorption characteristics increase gradually from the beginning of the collision as shown by the broken line in FIG. It is continued even after passing, and the pick value is suppressed, and sufficient absorption of impact energy is ensured.
[0038]
Further, if the subframe 40 is not coupled to the front support bracket 31 and the rear support bracket 34, as shown in FIG. 1, an impact load P2 from the front, for example, near the end of the horizontal frame 42 of the subframe 40, for example, When the impact load P2 is applied by being offset to the driver's seat side, the change points 42a and 42b of the driver's seat-side vertical frame 42 are relatively easily buckled and deformed relatively easily. Moreover, the G waveform rapidly increases from the beginning of the collision, and has a tendency to decrease rapidly after the peak, and there is a concern that effective impact energy absorption cannot be achieved.
[0039]
However, according to the present embodiment, the shape change points 42a and 42b of the vertical frame 42 or their vicinity and the change points 41a and 41b of the other vertical frame 41 or their vicinity are mutually connected to the suspension cross member 20 and the front. Since the left and right vertical frames 41 and 42 are integrated by being connected by the portion support bracket 31 and the rear bracket 34, for example, when an impact load P2 offset to the driver's seat side acts, the impact load P2 is The signals are distributed and transmitted from the vertical frame 42 to the other vertical frame 41, that is, the vertical frame 41 on the passenger seat side through the suspension cross member 20 and the like. As a result, the G waveforms of the impact energy absorption characteristics of the left and right vertical frames 41 and 42 gradually increase from the beginning of the collision and continue after the peak, and the peak value is suppressed and sufficient impact energy is absorbed. Is secured.
[0040]
Further, the front support bracket 31 that couples the suspension cross member 20 and the sub frame 40 also serves as a stabilizer mounting bracket, and the lower end of the rear support bracket 34 that supports the lower arm bush 51 is coupled to the sub frame 40. Therefore, compared to the conventional front structure of the vehicle body, it is possible to improve the support rigidity of the suspension and impact energy by the subframe without increasing the complexity of the structure and increasing the number of additional parts, leading to an increase in the vehicle weight and manufacturing cost. Is secured.
[0041]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the suspension cross member 20 can be integrally formed with the front support bracket 31 and the rear support bracket 34, and the lower end of the front bracket 36 of the rear support bracket 34 is coupled to the side frame 40 to connect the side frame 40 and The support rigidity of the lower arm bush 51 can be further increased, and a support bracket for connecting the suspension cross member 20 and the side frame 40 can be further added between the front bracket 31 and the rear support bracket 34. .
[0042]
【The invention's effect】
According to the vehicle body front structure of the present invention described above, the lower arm bush mounting portion is formed on the suspension cross member coupled to the side frame and the support bracket that is installed on the vertical frame of the sub frame and has secured rigidity. The suspension rigidity of the suspension lower arm supported by the vehicle is ensured, the suspension rigidity of the suspension is improved, the steering stability is improved, and the suspension cross member coupled to the vertical frame and the side frame of the sub frame is supported by the support bracket. Since it is connected, the sub frame is supported by the side frame, the resistance of the sub frame against the impact load from the front is secured, the impact energy absorption function is secured, and this structure is relatively simple and increases the weight of the vehicle body. Combined with not inviting One in which large it made to contribute to the car manufacturing industry.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of 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 a main part showing an outline of a conventional vehicle body front structure.
FIG. 5 is a perspective view of a main part showing an outline of a conventional vehicle body front structure.
[Explanation of symbols]
11, 12 Side frame 20 Suspension cross member 21 Upper surface 22 Front flange 23 Rear flange 31 Front support bracket 32 Subframe connection bracket 34 Rear support bracket 35 Rear bracket 36 Front bracket 37 Subframe connection brackets 41, 42 Vertical Frame 41a, 41b, 42a, 42b Shape change point 43 Horizontal frame 47 Stabilizer 50 Suspension lower arm 51 Lower arm bush

Claims (6)

Suspension cross members are stretched between the left and right side frames extending in the longitudinal direction of the vehicle body and coupled, and the rear ends of the suspension cross members are coupled to the side frames below the left and right side frames. In a vehicle body front structure comprising a left and right vertical frame and a subframe having a horizontal frame connecting the front portions of the two vertical frames,
Body front structure for an automobile, characterized in that it comprises a support bracket having a lower arm bushing mounting portion while connecting the vertical frame of the suspension cross member and the sub-frame. The support bracket is
2. The vehicle body front structure according to claim 1, wherein the lower arm bush mounting portion is provided at a portion close to a joint portion with the vertical frame. The support bracket is
A front support bracket having an upper portion coupled to a front portion of the suspension cross member and a lower end coupled to the vertical frame;
The vehicle body front structure according to claim 1 or 2, further comprising a rear support bracket having an upper portion coupled to a rear portion of the suspension cross member and a lower end coupled to the vertical frame. The suspension cross member is
A substantially U-shaped cross section that extends in the vehicle width direction and includes a front flange and a rear flange bent downward along the front surface and the front and rear edges of the upper surface,
4. The vehicle body front structure according to claim 3, wherein an upper portion of the front support bracket is coupled to the front flange, and an upper portion of the rear support bracket is coupled to the rear flange. The front support bracket is
It has a stabilizer fixing part,
The rear support bracket is
Front body structure for an automobile according to claim 3 or 4, characterized in that with the lower arm bushing mounting portion. The lower end of the support bracket
Front body structure for an automobile according to any one of claims 1 to 5, characterized in that it is coupled to a site near the shape change point or the shape change point of the longitudinal frame.

Images