Vehicle lower part structure

Abstract

To improve steering stability of a vehicle while suppressing influence on designability of the vehicle.SOLUTION: A vehicle lower part structure 12 includes a plurality of rectification members 31, 32 disposed on the lower surface of a vehicle body in the rear of a rear tire 14. The plurality of rectification members 31, 32 each have flat plate shapes, project downward from the lower surface of the vehicle body, and extend in a vehicle longitudinal direction. The plurality of rectification members 31, 32 are disposed at intervals in a vehicle width direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle underbody structure, and more particularly to a vehicle underbody structure that improves the handling stability of a vehicle.

Background Art

[0002] Conventionally, in vehicles such as automobiles, there has been known a technique of providing fins on a combination lamp at the rear of the vehicle, a side mirror at the front of the vehicle, etc. to improve the handling stability of the vehicle.

[0003] Patent Document 1 discloses a structure in which fins are provided on a side visor to improve the handling stability of a vehicle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] If fins are provided in a place that is easily visible to the user in a vehicle, the fins may affect the design of the vehicle. There is a need for a technique that improves the handling stability of a vehicle while suppressing the influence on the design of the vehicle.

[0006] An object of the present invention is to improve the handling stability of a vehicle while suppressing the influence on the design of the vehicle.

Means for Solving the Problems

[0007] The vehicle underbody structure according to the present invention includes a plurality of fairing members disposed on the lower surface of the vehicle body behind the rear tire. Each of the plurality of fairing members has a flat plate shape, protrudes downward from the lower surface of the vehicle body, and extends in the vehicle longitudinal direction. The plurality of fairing members are arranged at intervals in the vehicle width direction.

[0008] Further, in the vehicle underbody structure according to the present invention, the plurality of fairing members may be composed of a first fairing member and a second fairing member. The first fairing member is disposed inside the center in the width direction of the rear tire in the vehicle width direction, and the second fairing member is disposed outside the first fairing member in the vehicle width direction.

[0009] Further, in the vehicle underbody structure according to the present invention, the second fairing member may be disposed outside the center in the width direction of the rear tire in the vehicle width direction.

[0010] Further, in the vehicle underbody structure according to the present invention, the first fairing member may be longer in the vehicle longitudinal direction than the second fairing member.

[0011] Further, in the vehicle underbody structure according to the present invention, each of the plurality of fairing members includes a front portion having an inclined surface that slopes downward from the vehicle front to the vehicle rear, and a rear portion having an inclined surface that slopes upward from the vehicle front to the vehicle rear. In each of the plurality of fairing members, the inclined surface of the front portion may be steeper than the inclined surface of the rear portion.

Advantages of the Invention

[0012] According to the present invention, when the vehicle is running, the wind from the outside in the width direction of the rear tire and the wind from the inside thereof are rectified by a plurality of fairing members disposed behind the rear tire, so that the handling stability of the vehicle can be improved. Further, since the plurality of fairing members are disposed on the lower surface of the vehicle body that is less likely to be noticed by the user, the influence on the vehicle design due to the plurality of fairing members can be suppressed.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described herein. The same reference numerals are assigned to the same elements in all the drawings, and redundant descriptions are omitted. In the following description, unless otherwise specified, the terms indicating directions and orientations such as front, rear, left, right, up, and down represent the directions and orientations related to the vehicle. In each figure, the direction of arrow FR represents the front, the direction of arrow UP represents the up, and the direction of arrow RH represents the right. Also, the side closer to the center in the left - right direction (width direction) of the vehicle is referred to as the inner side in the vehicle width direction, and the side farther from the center is referred to as the outer side in the vehicle width direction.

[0015] FIG. 1 is a side view of the rear part of the vehicle 10, showing the right side of the vehicle 10. The vehicle 10 is an automobile. The vehicle 10 includes two front tires (not shown) and two rear tires 14 (only one is shown in FIG. 1).

[0016] The vehicle 10 may be an automobile such as an SUV (Sport Utility Vehicle) or a wagon, which has a relatively high vehicle height and a relatively high center of gravity. Such vehicles are generally disadvantageous in terms of handling stability. However, by adopting the vehicle lower structure 12 described below, the handling stability can be improved. Also, the vehicle lower structure 12 may be adopted for other automobiles such as sedans, thereby also improving the handling stability of those automobiles.

[0017] As shown in FIG. 1, the vehicle lower structure 12 includes a group of fairing members 30 disposed on the lower surface of the vehicle body behind the rear tire 14. The group of fairing members 30 consists of a first fairing member 31 and a second fairing member 32. FIG. 1 shows the first fairing member 31 and the second fairing member 32 that appear below the rear bumper 16. In the following, the group of fairing members 30 disposed behind the right rear tire 14 will be described, but a similar group of fairing members 30 is also disposed behind the left rear tire (not shown). That is, the vehicle 10 is provided with a pair of groups of fairing members 30 symmetrically on the left and right.

[0018] FIG. 2 is an enlarged view of the portion of the group of fairing members 30 in FIG. 1. In FIG. 2, a part of the outline of the first fairing member 31 located behind the second fairing member 32 is indicated by a dotted line. FIG. 3 is a perspective view of the rear bottom 40 of the vehicle 10. FIG. 4 is a perspective view of the group of fairing members 30 of the vehicle 10. Also, FIG. 5 is a bottom view of the group of fairing members 30 of the vehicle 10.

[0019] As shown in FIG. 3, the vehicle 10 includes a wheelhouse panel 42, a rear bumper 16, and a bottom member 24. The wheelhouse panel 42 forms the wheelhouse of the rear tire 14. The rear bumper 16 includes a side portion 18 and an edge portion 20 as shown in FIG. 4. The edge portion 20 is a portion bent downward from the side portion 18 of the rear bumper 16. In reality, the rear bumper 16 has a gradual shape change, that is, a gentle curved surface, between the side portion 18 and the edge portion 20, but in FIGS. 3 to 5, the curved surface is omitted and the shape of the rear bumper 16 is simplified.

[0020] The bottom member 24 is a resin part manufactured by, for example, injection molding. As shown in FIG. 3, the bottom member 24 includes a base plate 26 and a group of flow rectifying members 30. Note that the bottom member 24 further includes an upper part (not shown) connected to the base plate 26 disposed on the upper side (inside the vehicle body) of the base plate 26, and the upper part is fixed to a structure (not shown) provided at the rear of the vehicle. As shown in FIG. 3, the base plate 26 forms a part of the bottom surface of the vehicle body. The base plate 26 is disposed behind the wheelhouse panel 42.

[0021] As shown in FIG. 4, the base plate 26 of the bottom member 24 is disposed above the edge 20 of the rear bumper 16. The outer portion of the base plate 26 in the vehicle width direction is fixed to the edge 20 of the rear bumper 16 by screws 22.

[0022] As shown in FIG. 4, the first flow rectifying member 31 and the second flow rectifying member 32 are arranged in parallel at intervals in the vehicle width direction. The first and second flow rectifying members 31 and 32 respectively project downward from the base plate 26. The first and second flow rectifying members 31 and 32 respectively extend in the front-rear direction. That is, the direction in which the first and second flow rectifying members 31 and 32 extend coincides with the front-rear direction of the vehicle. The first and second flow rectifying members 31 and 32 respectively have a flat plate shape. The thickness (width in the vehicle width direction) of the first and second flow rectifying members 31 and 32 is constant or substantially constant in the front-rear direction.

[0023] The first flow rectifying member 31 includes a front part 31f, a main body part 31b, and a rear part 31r. The front part 31f has an inclined surface 31fs (see FIG. 2) that slopes downward from the front to the rear. The main body part 31b has a constant or substantially constant height. The rear part 31r has an inclined surface 31rs that slopes upward from the front to the rear.

[0024] Similarly, the second rectifying member 32 includes a front portion 32f, a main body portion 32b, and a rear portion 32r. The front portion 32f has an inclined surface 32fs (see FIG. 2) that slopes downward from front to rear. The main body portion 32b has a constant or substantially constant height. The rear portion 32r has an inclined surface 32rs that slopes upward from front to rear.

[0025] In each of the first and second rectifying members 31 and 32, the inclined surface 31fs (32fs) of the front portion 31f (32f) is steeper than the inclined surface 31rs (32rs) of the rear portion 31r (32r). The inclined surface 31fs (32fs) of the front portion 31f (32f) is relatively steep in order to capture the wind more quickly during vehicle travel and flow the wind along the main body portion 31b (32b). The inclined surface 31rs (32rs) of the rear portion 31r (32r) is relatively gentle from the viewpoint of appearance and to smoothly flow the wind that has flowed along the main body portion 31b (32b) rearward.

[0026] As shown in FIG. 2, the front end of the second rectifying member 32 is located slightly forward compared to the front end of the first rectifying member 31. Also, in this embodiment, as shown in FIG. 2, the height of the main body portion of the second rectifying member 32 is slightly higher than the height of the main body portion of the first rectifying member 31. Note that the height of the main body portion of the first rectifying member 31 and the height of the main body portion of the second rectifying member 32 may be the same.

[0027] Also, in this embodiment, as shown in FIG. 5, the first rectifying member 31 is longer in the front-rear direction than the second rectifying member 32. This difference in length depends on the limitation of the arrangement space. That is, as shown in FIG. 5, since the rear bumper 16 (vehicle body side portion) curves slightly from the outer side to the inner side in the vehicle width direction, the length of the second rectifying member 32 in the front-rear direction is limited compared to the first rectifying member 31. Note that if there is no such limitation, for example, when the shape of the vehicle body behind the rear tire 14 allows the extension of the length of the second rectifying member 32, the length of the second rectifying member 32 in the front-rear direction may be the same as or substantially the same as the length of the first rectifying member 31 in the front-rear direction.

[0028] As shown in FIG. 5, the first rectifying member 31 is disposed inside the center C in the width direction of the rear tire 14 in the vehicle width direction. The second rectifying member 32 is disposed outside the first rectifying member 31 in the vehicle width direction. Specifically, the second rectifying member 32 is disposed slightly outside the center C in the width direction of the rear tire 14 in the vehicle width direction. Further, the distance between the first rectifying member 31 and the second rectifying member 32 is narrower than the width of the rear tire 14.

[0029] Next, the operation and effect of the vehicle lower structure 12 provided with the first and second rectifying members 31 and 32 behind the left and right rear tires 14, that is, the embodiment described above will be described.

[0030] When the vehicle 10 travels forward, as shown in FIG. 5, winds W1 to W3 are generated behind the rear tire 14. The wind W1 is a wind that flows through the side surface of the vehicle, flows outside the width direction of the rear tire 14, and is drawn into the rear of the rear tire 14. The wind W2 is a wind that flows through the bottom surface of the vehicle body, flows inside the width direction of the rear tire 14, and enters the rear of the rear tire 14. The wind W3 is a wind that flows through the wheel house of the rear tire 14 and flows to the rear of the rear tire 14.

[0031] The flow rates of the winds W1 to W3 are different. In particular, the flow rates of the winds W1 and W2 are different. When these winds mix, that is, cross behind the rear tire 14, wind turbulence occurs and the stability of the vehicle 10 decreases.

[0032] However, according to the embodiments described above, the first and second rectifying members 31 and 32 can divide the winds W1 to W3, and the intersection of these winds can be reduced. That is, as shown in FIG. 5, most of the wind W1 can flow outside the second rectifying member 32 (outside in the vehicle width direction). The second rectifying member 32 suppresses the wind W1 from entering inward in the vehicle width direction behind the rear tire 14. That is, the second rectifying member 32 blocks the inward entry of the wind W1 in the vehicle width direction. Also, as shown in FIG. 5, most of the wind W2 can flow outside the first rectifying member 31 (inside in the vehicle width direction). The first rectifying member 31 suppresses the wind W2 from advancing outward in the vehicle width direction behind the rear tire 14. That is, the first rectifying member 31 blocks the outward advancement of the wind W2 in the vehicle width direction. Also, most of the wind W3 can flow between the first rectifying member 31 and the second rectifying member 32. In this way, by rectifying the wind flow with the first and second rectifying members 31 and 32, the handling stability of the vehicle 10 can be improved.

[0033] According to the embodiments described above, stable straight-ahead performance can be ensured during vehicle travel. Also, even when the steering wheel is turned (during steering) while the vehicle is running, wind turbulence can be reduced, enabling stable vehicle turning.

[0034] Also, according to the embodiments described above, since the first and second rectifying members 31 and 32 are arranged on the lower surface of the vehicle body, which is not easily noticeable to the user, the influence of the first and second rectifying members 31 and 32 on the design of the vehicle 10 can be suppressed. It is possible to achieve both the handling stability and the design (designability) of the vehicle 10.

[0035] FIG. 6 is a radar chart showing the effects of the vehicle lower structure 12 (with a fairing member) described above. A plurality of drivers drove a vehicle in which fins were provided on a conventional rear combination lamp (a combination lamp at the rear of the vehicle) (hereinafter referred to as a conventional vehicle), and a vehicle 10 that adopted the vehicle lower structure 12 of the present embodiment (hereinafter referred to as the subject vehicle), and evaluated 12 items related to handling stability. Of course, the conventional vehicle is not provided with the fairing member described above, and the subject vehicle is not provided with the fins of the conventional rear combination lamp. Then, for each item, a representative value showing the evaluation results of a plurality of drivers was obtained and plotted on the radar chart. As a result, FIG. 6 shows the evaluation results of the subject vehicle (with a fairing member) based on the conventional vehicle.

[0036] As shown in FIG. 6, it was confirmed that the subject vehicle, that is, the vehicle 10 provided with the first and second fairing members 31 and 32, can ensure handling stability equal to or higher than the standard (conventional vehicle). In particular, by providing the first and second fairing members 31 and 32 as compared with the standard (fins of the rear combination lamp), an improvement in "solid feeling (when going straight)", "good yaw response (near N)", and "rear transient grip feeling" was confirmed.

[0037] Note that the "solid feeling (when going straight)" is the stability of the vehicle when going straight, and it means that there is little feeling of being swayed left and right when driving straight. Also, the "good yaw response (near N)" is the responsiveness at the start of turning the steering wheel when the vehicle is running, and it is the goodness of the vehicle's reaction when the steering wheel is straight (N) and the steering wheel is turned slightly. Also, the "rear transient grip feeling" is the grip feeling of the rear part of the vehicle when the vehicle is suddenly lane-changed while the vehicle is running, and it means that the contact and stability of the rear tires can be felt when the vehicle is suddenly lane-changed.

[0038] From the above, it can be understood that the vehicle lower structure 12 of the present embodiment is an excellent structure from the viewpoint of handling stability.

[0039] In the embodiment described above, the rectifying member group 30 was constituted by two rectifying members (the first and second rectifying members 31 and 32). However, the rectifying member group 30 may be constituted by three or more rectifying members.

Explanation of Signs

[0040] 10 Vehicle, 12 Vehicle lower structure, 14 Rear tire (rear wheel), 16 Rear bumper, 18 Side portion, 20 Edge portion, 22 Screw, 24 Bottom member, 26 Base plate, 30 Rectifying member group, 31 Rectifying member (first rectifying member), 31b Body portion, 31f Front portion, 31fs Inclined surface, 31r Rear portion, 31rs Inclined surface, 32 Rectifying member (second rectifying member), 32b Body portion, 32f Front portion, 32fs Inclined surface, 32r Rear portion, 32rs Inclined surface, 40 Rear bottom, 42 Wheelhouse panel.

Claims

1. A vehicle underbody structure, comprising a plurality of fairing members disposed on the lower surface of the vehicle body behind the rear tire, wherein each of the plurality of fairing members has a flat plate shape, protrudes downward from the lower surface of the vehicle body, and extends in the vehicle longitudinal direction, and the plurality of fairing members are arranged at intervals in the vehicle width direction. Vehicle underbody structure.

2. The vehicle underbody structure according to Claim 1, wherein the plurality of fairing members consist of a first fairing member and a second fairing member, the first fairing member is disposed inside the center in the width direction of the rear tire in the vehicle width direction, and the second fairing member is disposed outside the first fairing member in the vehicle width direction. Vehicle underbody structure.

3. The vehicle underbody structure according to Claim 2, wherein the second fairing member is disposed outside the center in the width direction of the rear tire in the vehicle width direction. Vehicle underbody structure.

4. The vehicle underbody structure according to Claim 2 or 3, wherein the first fairing member is longer in the vehicle longitudinal direction than the second fairing member. Vehicle underbody structure.

5. The vehicle underbody structure according to any one of Claims 1 to 3, wherein each of the plurality of fairing members includes a front portion having an inclined surface that slopes downward from the vehicle front to the vehicle rear, and a rear portion having an inclined surface that slopes upward from the vehicle front to the vehicle rear, and in each of the plurality of fairing members, the inclined surface of the front portion is steeper than the inclined surface of the rear portion. Vehicle underbody structure.

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