Vehicle front structure

Abstract

To materialize a vehicle front structure that inhibits concentration of a stress on a coupling part between a brace and vehicle body, ensures vehicle body rigidity, and upgrades steering stability.SOLUTION: A vehicle front structure includes left and right front side members 20 extending in a vehicular fore-and-aft direction, a front suspension member 30 that is located below the left and right front side members 20, extends in a vehicle crosswise direction, and supports left and right front suspensions at left and right sides, and a brace 40 whose forward coupling parts 42 at two left and right forward positions are coupled to the rear part of the front suspension member 30 and whose backward coupling parts 44 at two left and right backward positions are coupled to the respective left and right front side members 20. The brace 40 is shaped like a substantially square frame having an opening 46. Parts 48 of the brace 40 extending in the vehicular fore-and-aft direction from the respective forward coupling parts 42 to the respective backward coupling parts 44 are curved inward in the vehicle width direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle front structure.

Background Art

[0002] Structures have been proposed to improve the rigidity of the vehicle body and the riding comfort and handling stability of the vehicle. For example, in a vehicle front structure, in order to increase the rigidity of the vehicle body, a structure is known in which a brace is provided as a reinforcing member that connects the front suspension member and the vehicle body.

[0003] Patent Document 1 discloses a front subframe structure that improves the rigidity of the vehicle body by providing a truss-structured brace at the rear of the front subframe.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a vehicle front structure provided with a brace that connects the front suspension member and the vehicle body, when a load is input, the input load may concentrate on the connection portion between the brace and the vehicle body. For example, when a load in the longitudinal direction of the vehicle due to sudden acceleration or sudden braking is input, the load is transmitted from the front suspension member to the brace and further to the connection portion between the brace and the vehicle body, and high stress is generated at the connection portion. As a result, the fatigue strength of the connection portion decreases.

[0006] Therefore, this specification discloses a vehicle front structure that suppresses stress concentration due to an input load at the connection portion between the brace and the vehicle body, while ensuring the rigidity of the vehicle body and improving handling stability.

Means for Solving the Problems

[0007] The vehicle front structure disclosed in this specification is disposed on the right and left sides of the front portion of the vehicle, and includes left and right front side members extending in the longitudinal direction of the vehicle, and front suspension members provided below the left and right front side members, extending in the left-right direction of the vehicle, and supporting left and right front suspensions on both left and right sides respectively. The brace has front connection portions at two locations on the left and right in the front respectively connected to the rear portion of the front suspension member, and rear connection portions at two locations on the left and right in the rear respectively connected to the left and right front side members. The brace has a substantially rectangular frame shape having an opening penetrating in the vertical direction of the vehicle at the center. In the brace, a portion extending from the front connection portion to the rear connection portion and extending in the longitudinal direction of the vehicle is curved inward in the width direction of the vehicle. This is the gist of the invention.

Advantages of the Invention

[0008] According to the vehicle front structure disclosed in this specification, by providing a brace as a reinforcing member for connecting the front suspension member and the vehicle body, the rigidity of the vehicle body can be improved and the handling stability can be improved. Further, by forming the shape of the brace into a substantially rectangular frame shape having an opening at the center, when a load in the longitudinal direction of the vehicle is input, the shape of the brace is deformed and the load transmitted to the connection portion between the front suspension member and the vehicle body is reduced. As a result, stress concentration at the connection portion can be prevented.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the vehicle front structure will be described with reference to the drawings. In each figure, "Fr", "Up", and "W" indicate the vehicle front, upward, and vehicle width directions, respectively. Also, the left and right in the vehicle width direction are defined as the left and right when viewed from the vehicle front.

[0011] FIG. 1 is a schematic bottom view of the vehicle front structure. The vehicle front structure includes, at the lower part of the vehicle body 10, left and right front side members 20, a front suspension member 30, and a brace 40. Note that, although the vehicle front structure disclosed in this specification is described using the left and right front side members 20 as an example of the vehicle body frame, it is not limited thereto and other vehicle body framework members are also included.

[0012] The left and right front side members 20 are one of the members that constitute the framework of the vehicle body 10 disposed on the right and left sides at the front part of the vehicle, and extend in the longitudinal direction of the vehicle. A front suspension member 30 is disposed on the lower side of the vehicle of the left and right front side members 20. The front suspension member 30 extends in the vehicle width direction and supports left and right front suspensions (not shown) on both the left and right sides, respectively.

[0013] The brace 40 is a reinforcing member that connects the front suspension member 30 and the left and right front side members 20. As shown in FIG. 1, the brace 40 includes left and right front connecting portions 42, left and right rear connecting portions 44, an opening 46, and a curved surface portion 48. The left and right front connecting portions 42 are respectively provided at two locations on the left and right in the front of the vehicle of the brace 40. The left and right front connecting portions 42 are respectively connected to the rear portion of the front suspension member 30 by welding or bolts or the like. The left and right rear connecting portions 44 are respectively provided at two locations on the left and right in the rear of the vehicle of the brace 40. The left and right rear connecting portions 44 are respectively connected to the left and right front side members 20 by welding or bolts or the like. The opening 46 is provided at the center of the brace 40 so as to penetrate in the vertical direction of the vehicle. The shape of the opening 46 is substantially rectangular. Therefore, the shape of the brace 40 is a substantially rectangular frame shape having the opening 46 at the center. The curved surface portions 48 are respectively provided on the left and right so as to extend in the longitudinal direction of the vehicle on the outer side in the vehicle width direction of the brace 40. More specifically, the right curved surface portion 48 is a portion extending from the right front connecting portion 42 to the right rear connecting portion 44, and the left curved surface portion 48 is a portion extending from the left front connecting portion 42 to the left rear connecting portion 44. The curved surface portions 48 are respectively curved so as to be recessed inward in the vehicle width direction.

[0014] Next, with reference to FIG. 2, the brace 40 when a load is input will be described. FIG. 2 is a side view showing the deformation of the brace 40 when a load is input. In FIG. 2, the deformed state of the brace 40 when a load is input from the front of the vehicle is shown by a solid line. Note that the shape shown by the dashed line in FIG. 2 indicates the state where no load is input, that is, the shape of the brace 40 before deformation.

[0015] As shown by the solid line in FIG. 2, when a load is input to the vehicle body 10 from the front of the vehicle, the load is transmitted to the brace 40. Then, the brace 40 is elastically deformed so as to bulge downward in the vehicle. More specifically, in the brace 40, the portion that is elastically deformed is the portion on the outer side in the vehicle width direction of the opening 46, in other words, the portion that is curved inward in the vehicle width direction of the curved surface portion 48. This is due to providing the opening 46 at the center of the brace 40 to form the brace 40 into a frame shape, and providing the curved surface portion 48 on the brace 40. That is, compared with a brace that does not have an opening or a curved surface portion, the brace 40 disclosed in this specification is more likely to be deformed when a load in the front-rear direction is input. In particular, since the curved surface portion 48 is curved inward in the vehicle width direction, when a force is applied in the vehicle front-rear direction, the curved surface portion 48 is deformed, and the load on the rear connecting portion 44 can be reduced.

[0016] For example, if the brace is not in the shape of this example, when a load in the vehicle front-rear direction is input due to sudden acceleration or sudden braking, the load is transmitted to the left and right rear connecting portions 44, and high stress is generated in the rear connecting portions 44. Then, when repeated stress is generated in the rear connecting portions 44, the strength of the rear connecting portions 44 is reduced. However, since the brace 40 disclosed in this specification is more likely to be deformed when a load in the front-rear direction is input, the load transmitted to the left and right rear connecting portions 44 is suppressed, and stress concentration in the left and right rear connecting portions 44 can be prevented.

[0017] Here, for example, a configuration in which the brace 40 is made thin in the vehicle vertical direction (that is, in the plate thickness direction) to make it easier to deform is also conceivable. However, if the brace 40 is made thin, the strength will decrease. On the other hand, the brace 40 disclosed in this specification is more likely to be deformed even when the plate thickness is ensured by forming it into a substantially square frame shape having the opening 46 at the center, and further by providing the curved surface portion 48. Furthermore, by being able to ensure the plate thickness of the brace 40, the influence on the brace 40 when a load in the vehicle vertical direction occurs when interfering with the road surface such as riding up on a curb can be suppressed. As a result, deformation of the brace 40 in the vehicle vertical direction can be prevented.

[0018] In addition, by forming the brace 40 into a substantially rectangular frame shape with the opening 46 at the center, it is possible to ensure the rigidity when a load is input in the vehicle left - right direction. When a load is input in the left - right direction, since the brace 40 is substantially rectangular, that is, since a part of the brace 40 also exists in the vehicle width direction, the rigidity of the brace 40 can be ensured, and thus the rigidity of the vehicle body 10 can be ensured.

[0019] As described above, by providing the opening 46 at the center and forming the brace 40 into a frame shape, and by providing the curved surface portion 48, it is possible to prevent stress concentration at the rear connection portion 44 when a load is input in the vehicle front - rear direction, and to ensure the rigidity of the brace 40 when a load is input in the vehicle left - right direction. That is, while suppressing the concentration of stress due to the input load at the rear connection portion 44, the rigidity of the vehicle body 10 can be ensured and the handling stability can be improved.

[0020] Next, with reference to FIG. 3, the shape of the brace when the position of the exhaust pipe and the brace is close will be described. FIG. 3 is a schematic bottom view of the vehicle front - part structure and shows a case where the position of the exhaust pipe and the brace is close. Since the brace 40 shown in FIG. 3 corresponds to the brace 40 shown in FIG. 1, the same reference numerals are given to the same components and their description is omitted.

[0021] As shown in FIG. 3, the brace 40 has a brace front - end portion 50 whose front part in the vehicle front - rear direction is U - shaped. That is, the front part of the brace 40 has a shape in which its central part is recessed in a U - shape toward the rear of the vehicle. More specifically, in the brace 40 shown in FIG. 3, the left and right front connection portions 42 are respectively connected to the rear part of the front suspension member 30. On the other hand, since the brace front - end portion 50, which is the part connecting the right front connection portion 42 and the left front connection portion 42, is U - shaped, its substantially central and peripheral portions will not interfere with the rear part of the front suspension member 30.

[0022] In addition, in the vehicle front structure shown in FIG. 3, at the lower part of the vehicle body 10, an exhaust pipe 60 and a bracket 70 are further provided. In this example, the brace 40 is arranged at a position close to the exhaust pipe 60. Here, the close position means a position where the heat from the exhaust pipe 60 is directly transmitted to the brace 40. The bracket 70 is a member that supports the exhaust pipe 60 and is connected to approximately the center of the rear part of the front suspension member 30. As shown in FIG. 3, the bracket 70 is arranged below the front suspension member 30 and above the brace 40. Further, the bracket 70 is arranged so as to extend in the vehicle front-rear direction at approximately the center of the front end portion 50 of the brace.

[0023] In order to suppress the displacement of the exhaust pipe 60 and improve the NVH characteristics, it is desirable to provide a bracket 70 as a member that supports the exhaust pipe 60. Here, in the vehicle front structure shown in FIG. 3, by providing a brace front end portion 50 with a U-shaped concave front end in the brace 40, interference between the brace front end portion 50 and the bracket 70 can be avoided. Further, when the positions of the exhaust pipe 60 and the brace 40 are close, the brace 40 may be affected by heat damage from the exhaust pipe 60. However, in the brace 40 disclosed in this specification, since it has a shape with an opening 46 provided at the center, heat damage from the exhaust pipe 60 can be prevented.

[0024] As described above, in the vehicle front structure shown in FIG. 3, the recessed portion at the rear in the U-shaped brace front end portion 50 does not interfere with the front suspension member 30. Further, the brace 40 shown in FIG. 3 has a structure with an opening 46 provided at the center, so that even in a structure where the positions of the exhaust pipe 60 and the brace 40 are close as in this example, the influence of heat damage to the brace 40 can be suppressed.

[0025] Note that the descriptions so far are just examples. The vehicle front structure only needs to have, at least, a substantially rectangular frame shape in which the brace 40 has the opening 46, and have a curved surface portion 48 that extends from the front connection portion 42 to the rear connection portion 44 (that is, extends in the vehicle longitudinal direction) and curves inward in the vehicle width direction. Therefore, the configurations of other vehicle front structures may be changed as appropriate. For example, the brace 40 disclosed in this specification is provided with the left and right front connection portions 42 that are connected to the rear portion of the front suspension member 30, but the front connection portion is not limited to two locations on the left and right.

Description of Reference Numerals

[0026] 10 Vehicle body, 20 Front side member, 30 Front suspension member, 40 Brace, 42 Front connection portion, 44 Rear connection portion, 46 Opening, 48 Curved surface portion.

Claims

【Claim 1】 Left and right front side members disposed on the right and left sides of the front portion of the vehicle and extending in the longitudinal direction of the vehicle; A front suspension member provided below the left and right front side members, extending in the left - right direction of the vehicle, and supporting left and right front suspensions on both left and right sides respectively; A brace having front connection portions at two left - right positions in the front respectively connected to the rear portion of the front suspension member, and rear connection portions at two left - right positions in the rear respectively connected to the left and right front side members; Comprising: The brace has a substantially rectangular frame shape having an opening penetrating in the vertical direction of the vehicle at the center; In the brace, a portion extending from the front connection portion to the rear connection portion and extending in the longitudinal direction of the vehicle is curved inward in the width direction of the vehicle; A vehicle front - part structure characterized by the above.

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