Airflow adjustment installation of vehicle rear part

Abstract

To provide an airflow adjustment installation of a vehicle rear part capable of attaining both reduction in a travel resistance of a vehicle and reduction in a wind noise.SOLUTION: An airflow adjustment installation of a vehicle rear part is adapted to a vehicle having a bumper 11 attached to a rear end. An air passage 12 is formed above the bumper 11 of the vehicle. Air flowing below the floor of the vehicle during travel is led to behind a rear surface 14 of the vehicle through the air passage 12. A movable member 15 forming the air passage 12 is interposed between a rear part of the vehicle in front of the bumper 11 and the bumper 11. The movable member 15 can move in a direction of approaching the bumper 11 or a direction receding from the bumper. The movable member 15 changes an air circulation cross-sectional area of the air passage 12 on the basis of the movement.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an airflow conditioning device for a rear of a vehicle. [Background technology]

[0002] When a vehicle is moving, air flows over the roof and under the floor of the vehicle. The speed of the air flow under the floor tends to be slower than the speed of the air flow over the roof due to factors such as the distance between the floor and the road surface. When the speed of the air flow under the floor is slower than the speed of the air flow over the roof, the generation of vortices in the air flow behind the vehicle becomes unbalanced, resulting in a wide area behind the vehicle where the air flow is slow. This wide area behind the vehicle where the air flow is slow increases the vehicle's running resistance, resulting in adverse effects such as a deterioration in the vehicle's fuel economy and power consumption.

[0003] Furthermore, the vehicle disclosed in Patent Document 1 has an air passage formed above a bumper located at the rear end of the vehicle, and air flowing under the floor of the vehicle while the vehicle is moving is directed to the rear of the rear surface of the vehicle through the air passage. In this case, when the vehicle is moving, air flows from under the floor to the rear of the vehicle's rear surface through the air passage, creating a fast air flow from under the floor toward the rear of the vehicle's rear surface. As a result, the fast air flow from under the floor toward the rear of the vehicle can be made to be closer to the fast air flow over the roof, thereby narrowing the area of ​​slow air flow occurring behind the vehicle in the vertical direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-85416 Summary of the Invention [Problem to be solved by the invention]

[0005] In the vehicle of Patent Document 1, the area behind the vehicle where the air flow is slow is narrowed, so the increase in the running resistance of the vehicle can be suppressed, and the impact of the running resistance on the fuel economy and electricity consumption of the vehicle can be minimized. However, when a vehicle with low external noise is traveling at low speed, if air flows from under the floor through the air passage to the rear side of the rear of the vehicle, the wind noise at the rear of the vehicle caused by the air flow becomes relatively loud compared to the external noise.

[0006] The wind noise is caused by air flowing from under the floor through the air passage to the rear of the vehicle when the downward vortex of air flow generated from above the roof to the rear of the vehicle is weak. In other words, when air flows from under the floor through the air passage to the rear of the vehicle under the above-mentioned conditions, the upward vortex of air flow behind the rear of the vehicle becomes stronger, and the air vortex hits the rear of the vehicle, causing wind noise.

[0007] When a vehicle with low external noise is traveling at low speeds, if the wind noise becomes relatively loud compared to the external noise, the vehicle occupants may feel uncomfortable due to the wind noise, which could reduce the comfort of the vehicle occupants. [Means for solving the problem]

[0008] Next, various aspects of the air flow control device for the rear of a vehicle that solves the above problems will be described. (Aspect 1) In an air flow control device for a rear of a vehicle that is applied to a vehicle with a bumper at the rear end, an air passage is formed above the bumper of the vehicle, and air flowing under the floor of the vehicle when in motion is directed to the rear of the rear of the vehicle through the air passage, a movable member that forms the air passage between the bumper and the movable member is positioned in front of the bumper at the rear of the vehicle, and the movable member is capable of moving toward or away from the bumper, and the air flow cross-sectional area of ​​the air passage is changed based on this movement.

[0009] According to the above configuration, the cross-sectional area of ​​the air flow in the air passage can be changed by moving the movable member relative to the bumper. Therefore, the cross-sectional area of ​​the air flow in the air passage can be adjusted by moving the movable member relative to the bumper so that wind noise caused by air flowing through the air passage can be reduced while reducing vehicle running resistance. By adjusting the cross-sectional area of ​​the air flow in this way, it is possible to achieve both reduced vehicle running resistance and reduced wind noise.

[0010] (Aspect 2) The air flow control device for the rear of a vehicle described in (embodiment 1) is configured such that when the vehicle speed is above a threshold value, the movable member moves away from the bumper than when the vehicle speed is below the threshold value, thereby increasing the cross-sectional area of ​​air flow in the air passage.

[0011] According to the above configuration, when the vehicle speed is high, such as when the vehicle speed is above a threshold, the movable member moves away from the bumper, thereby increasing the cross-sectional area of ​​the air flow in the air passage between them. This generates a fast air flow from under the floor toward the rear of the vehicle through the air passage, making the fast air flow from under the floor toward the rear of the vehicle closer to the fast air flow over the vehicle roof. As a result, the area of ​​slow air flow occurring behind the vehicle is narrowed in the vertical direction, thereby suppressing an increase in the vehicle's running resistance. On the other hand, when the vehicle speed is low, such as when the vehicle speed is below a threshold, the movable member moves closer to the bumper, thereby reducing the cross-sectional area of ​​the air flow in the air passage between them. This prevents the upward vortex of the air flow behind the rear of the vehicle from becoming stronger due to air flow from under the floor to the rear of the vehicle through the air passage, even when the downward vortex of the air flow occurring from the roof toward the rear of the vehicle is weak. As a result, wind noise caused by the air vortex hitting the rear of the vehicle can be reduced.

[0012] (Aspect 3) An air flow adjustment device for the rear of a vehicle as described in (Aspect 1) or (Aspect 2), which is provided with a rail that guides the movement of the movable member relative to the bumper, and the movable member moves toward or away from the bumper by moving along the rail.

[0013] According to the above configuration, the movement path of the movable member is determined by the rail, and by adjusting the extension and bending of the rail, the movable member can be moved so as to avoid surrounding obstacles.

[0014] (Aspect 4) The movable member forms an air passage between the movable member and the bumper so as to extend longitudinally in the width direction of the vehicle, and the air passage has a different air flow cross-sectional area between the center and both ends in the width direction of the vehicle (an air flow adjustment device for a rear of a vehicle described in any one of (Aspect 1) to (Aspect 3).

[0015] According to the above configuration, by making the cross-sectional area of ​​the air flow in the central portion of the air passage different from that at both ends in the vehicle width direction, it is possible to adjust the flow of air passing through the air passage so as to be effective in reducing the running resistance of the vehicle and reducing wind noise. By adjusting the flow of air passing through the air passage in this way, it is possible to more effectively reduce both the running resistance of the vehicle and wind noise.

[0016] (Aspect 5) The airflow regulator device for a rear portion of a vehicle according to any one of (Aspect 1) to (Aspect 4), wherein a storage space is formed in the movable member.

[0017] According to the above configuration, the movable member can be used to store tools and the like. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing an entire vehicle to which an air flow adjustment device is applied; [Figure 2] 2 is a schematic diagram showing the structure of a movement mechanism in the air flow control device of FIG. 1. [Figure 3] 3 is a schematic diagram showing the bumper and the movable member of FIG. 2 as viewed from below. [Figure 4] 4 is a schematic view showing the bumper and the movable member of FIG. 3 as viewed from the direction of the arrow. [Figure 5] 10 is a schematic diagram showing another example of a movable member. [Figure 6] 6 is a schematic view showing the bumper and the movable member of FIG. 5 as viewed from the direction of the arrow. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of an air flow regulator for a rear portion of a vehicle will be described with reference to FIGS. As shown in Figure 1, a bumper 11 is disposed at the rear end of the vehicle, i.e., at the right end in Figure 1. The bumper 11 extends in the width direction of the vehicle, i.e., in a direction perpendicular to the plane of the paper in Figure 1. An air passage 12 is formed above the bumper 11 in the vehicle. This air passage 12 is intended to direct air that flows under a floor 13 of the vehicle when the vehicle is moving to the rear side of a rear surface 14 of the vehicle.

[0020] A movable member 15 is disposed in front of a bumper 11 at the rear of the vehicle, forming the air passage 12 between itself and the bumper 11. The movable member 15 is capable of moving toward or away from the bumper 11. The movable member 15 changes the cross-sectional area of ​​air flow in the air passage 12 based on the movement. When the vehicle speed is equal to or greater than a threshold value, the movable member 15 moves away from the bumper 11 more than when the vehicle speed is below the threshold value, thereby increasing the cross-sectional area of ​​air flow in the air passage 12.

[0021] More specifically, when the vehicle speed is below a threshold value, the movable member 15 is brought close to the bumper 11 until it comes into contact with the bumper 11, thereby reducing the cross-sectional area of ​​air flow in the air passage 12 to approximately zero. As a result, the air passage 12 is closed, so that air flowing under the floor 13 of the vehicle during travel does not flow to the rear side of the rear surface 14 of the vehicle through the air passage 12. Furthermore, when the vehicle speed is equal to or greater than a threshold value, the movable member 15 is moved away from the bumper 11, thereby increasing the cross-sectional area of ​​air flow in the air passage 12 to a predetermined set value.

[0022] <Purpose of changing the cross-sectional area of ​​air flow in the air passage 12> When a vehicle is moving, air flows over the roof 16 and under the floor 13 of the vehicle. Arrow Y1 in Fig. 1 indicates the air flow along the roof 16 of the moving vehicle. Arrow Y2 in Fig. 1 indicates the air flow along the floor 13 of the moving vehicle. In this air flow, the speed of the air flow under the floor 13 indicated by arrow Y2 tends to be slower than the speed of the air flow above the roof 16 indicated by arrow Y1 due to the influence of factors such as the distance between the floor 13 and the road surface 17.

[0023] If the speed of the air flow below the floor 13, indicated by arrow Y2, becomes slower than the speed of the air flow above the roof 16, indicated by arrow Y1, the vortexes generated behind the vehicle will become unbalanced, resulting in a wide area of ​​slow air flow behind the vehicle. When this wide area of ​​slow air flow occurs above and below the vehicle, as indicated by the two-dot chain line L1, the vehicle's running resistance will increase. This will result in adverse effects such as a deterioration in fuel economy and power consumption.

[0024] However, when the vehicle is traveling, air flows from under the floor 13 to the rear side of the vehicle's rear surface 14 through the air passage 12, creating a fast air flow from under the floor 13 toward the rear side of the vehicle's rear surface 14, as shown by arrow Y3 in Figure 1. As a result, the fast air flow from under the floor 13 toward the rear side of the vehicle can be made closer to the fast air flow over the roof 16, and the area of ​​slow air flow occurring behind the vehicle becomes narrower in the vertical direction, as shown by the two-dot chain line L2 in Figure 1. This makes it possible to prevent the vehicle's running resistance from increasing, minimizing the impact of that running resistance on the vehicle's fuel economy and power consumption.

[0025] However, when a vehicle with low external noise is traveling at low speed, if air flows from under the floor 13 through the air passage 12 to the rear side of the vehicle's rear surface 14 as shown by arrow Y3, wind whipping noise at the vehicle's rear surface 14 caused by the air flow becomes relatively louder than the external noise. The wind whipping noise occurs when air flows from under the floor 13 through the air passage 12 to the rear side of the vehicle's rear surface 14 under conditions in which the downward airflow vortex generated from above the roof 16 to the rear side of the vehicle is weak. That is, when air flows from under the floor 13 through the air passage 12 to the rear side of the vehicle's rear surface 14 under the conditions described above, the upward airflow vortex behind the vehicle's rear surface 14 becomes stronger, and the air vortex hits the vehicle's rear surface 14, causing wind whipping noise. When a vehicle with low external noise is traveling at low speed, if the wind whipping noise becomes relatively louder than the external noise, the vehicle occupants may feel uncomfortable due to the wind whipping noise, which could reduce the comfort of the vehicle occupants.

[0026] To address these issues, movable member 15 operates as follows: When the vehicle speed is high, such as when the vehicle speed is equal to or greater than a threshold, movable member 15 moves away from bumper 11 more than when the vehicle speed is below the threshold, thereby increasing the cross-sectional area of ​​air flow in air passage 12 between them until it reaches a set value. As a result, the area behind the vehicle, indicated by the two-dot chain line L2, where the air flow is slow, becomes narrower in the vertical direction, thereby preventing the vehicle's running resistance from increasing.

[0027] On the other hand, when the vehicle speed is low, such as when it is below a threshold value, the movable member 15 approaches the bumper 11, thereby reducing the cross-sectional area of ​​air flow in the air passage 12 between them to almost zero. This reduces the air flow from under the floor 13 toward the rear side of the vehicle's rear surface 14 through the air passage 12 to almost zero. As a result, under conditions in which the downward vortex of air flow generated from above the roof 16 toward the rear side of the vehicle is weak, the upward vortex of air flow behind the vehicle's rear surface 14 due to air flowing from under the floor 13 through the air passage 12 to the rear side of the vehicle's rear surface 14 can be prevented from becoming stronger. Therefore, wind noise caused by the air vortex hitting the rear surface 14 of the vehicle can be reduced.

[0028] The set value may be a value determined in advance through experiments, etc. The threshold value may be, for example, 80 km / h.

[0029] <Structure for moving the movable member 15> 2, the movable member 15 is moved toward or away from the bumper 11 by a movement mechanism 18. A storage space 22 capable of storing tools and the like is formed inside the movable member 15. The movement mechanism 18 includes a rail 19, a cart 20, and a drive unit 21.

[0030] The rail 19 is for guiding the movement of the movable member 15 relative to the bumper 11. The rail 19 extends in the direction in which the movable member 15 is moved. More specifically, the rail 19 starts from a position close to the bumper 11, extends forward from the bumper 11 in a straight line, and then curves to extend forward and diagonally upward.

[0031] The carriage 20 is equipped with wheels 23 that are guided to roll along the rails 19. This allows the carriage 20 to move along the rails 19. The movable member 15 is fixed to the carriage 20. Therefore, the movable member 15 moves along the rails 19 as the carriage 20 moves. The movement trajectory of the movable member 15 can be freely determined by the extension and curvature of the rails 19. The rails 19 in this embodiment are determined so as to avoid surrounding obstacles when the movable member 15 is moved, for example.

[0032] The drive device 21 includes a front roller 24, a rear roller 25, a belt 26, and a connecting member 27. The rear roller 25 is disposed near the bumper 11. The front roller 24 is disposed forward of the rear roller 25 with respect to the bumper 11. The belt 26 is wound around the front roller 24 and the rear roller 25. The connecting member 27 connects the belt 26 to the carriage 20.

[0033] The driving device 21 rotates one of the front roller 24 and the rear roller 25 forward or backward, thereby causing the belt 26 to revolve around the front roller 24 and the rear roller 25. As the belt 26 moves around the front roller 24 and the rear roller 25, the carriage 20 connected to the belt 26 via the connecting member 27 moves along the rail 19. As a result, the movable member 15 fixed to the carriage 20 also moves along the rail 19, approaching or moving away from the bumper 11.

[0034] <Cross-sectional shape of air passage 12> 3 shows the bumper 11 and the movable member 15 as viewed from below in FIG. 2, and FIG. 4 shows the bumper 11 and the movable member 15 as viewed from the direction of the arrow in FIG.

[0035] As can be seen from Figure 3, the rear portion of the movable member 15, i.e., the upper portion in Figure 3, is formed so that the width in the left-right direction in Figure 3, which is the width direction of the vehicle, increases toward the rear of the vehicle. The above-mentioned air passage 12 is formed between such movable member 15 and the bumper 11, as shown in Figure 4. For this reason, the air passage 12 is also formed so as to be elongated in the width direction of the vehicle, i.e., the left-right direction in Figure 4.

[0036] The cross-sectional area of ​​air flow in the air passage 12 can be considered to be approximately the same at the center and both ends in the width direction of the vehicle. In other words, the distance between the opposing surfaces of the movable member 15 and the bumper 11 that form the air passage 12 is made approximately constant over the entire width direction of the vehicle.

[0037] Next, the operation and effect of the air flow control device for the rear of the vehicle according to this embodiment will be described. (1) The movable member 15 is capable of moving toward or away from the bumper 11. Based on this movement, the movable member 15 changes the cross-sectional area of ​​air flow in the air passage 12 formed between the bumper 11 and the movable member 15. Therefore, the cross-sectional area of ​​air flow in the air passage 12 can be adjusted by moving the movable member 15 relative to the bumper 11, so that the running resistance of the vehicle can be reduced while wind noise caused by air flowing through the air passage 12 can be reduced.

[0038] Specifically, when the vehicle speed is high, such as above a threshold, the movable member 15 moves away from the bumper 11, thereby increasing the cross-sectional area of ​​air flow in the air passage 12 between them. This causes a fast air flow from under the floor 13 through the air passage 12 toward the rear side of the vehicle's rear surface 14, making it possible to make the fast air flow from under the floor 13 toward the rear side of the vehicle closer to the fast air flow over the vehicle's roof 16. As a result, the area of ​​slow air flow occurring behind the vehicle becomes narrower in the vertical direction, thereby suppressing an increase in the vehicle's running resistance.

[0039] On the other hand, when the vehicle speed is low, such as when it is below a threshold value, the movable member 15 approaches the bumper 11, thereby reducing the cross-sectional area of ​​air flow in the air passage 12 between them. This reduces the air flow from under the floor 13 through the air passage 12 toward the rear side of the vehicle's rear surface 14. As a result, under conditions in which the downward vortex of air flow generated from above the roof 16 toward the rear side of the vehicle is weak, the upward vortex of air flow behind the vehicle's rear surface 14, which is caused by air flowing from under the floor 13 through the air passage 12 to the rear side of the vehicle's rear surface 14, can be prevented from becoming stronger. Therefore, wind noise caused by the air vortex hitting the rear surface 14 of the vehicle can be reduced.

[0040] In this way, by adjusting the air flow cross-sectional area in the air passage 12 in accordance with the vehicle speed, it is possible to reduce both the running resistance of the vehicle and wind noise. (2) The path of movement of the movable member 15 when the movable member 15 is moved toward or away from the bumper 11 is determined by the rails 19 of the movement mechanism 18. Therefore, by adjusting the extension and bending of the rails 19, the movable member 15 can be moved so as to avoid surrounding obstacles.

[0041] (3) The movable member 15 is formed with a storage space 22. Tools and the like can be stored in this storage space 22. Therefore, the movable member 15 can be used to store tools and the like.

[0042] The above embodiment can be modified as follows, for example: The above embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. When the vehicle speed is below a threshold value, instead of bringing the movable member 15 closer to the bumper 11 so that the cross-sectional area of ​​the air flow in the air passage 12 is approximately zero, the movable member 15 may be brought closer to the bumper 11 so that the cross-sectional area of ​​the air flow is greater than zero.

[0043] The movable member 15 may be divided into a plurality of pieces in the width direction of the vehicle, as shown in Fig. 5. Such a plurality of movable members 15 move toward or away from the bumper 11 as a unit. In this case, by making the sizes of the plurality of movable members 15 different, the cross-sectional area of ​​air flow in the air passage 12 may be made different between the center and both ends in the width direction of the vehicle, i.e., in the left-right direction in Fig. 6, as shown in Fig. 6.

[0044] As described above, by making the air flow cross-sectional area different between the center and both ends in the vehicle width direction in the air passage 12, it is possible to adjust the air flow passing through the air passage 12 so that it is effective in reducing the running resistance of the vehicle and reducing wind noise. By adjusting the air flow passing through the air passage 12 in this way, it is possible to further effectively reduce both the running resistance of the vehicle and wind noise.

[0045] Although 80 km / h is used as an example of the threshold value, other values ​​can also be used. The housing space 22 does not necessarily have to be formed in the movable member 15 .

[0046] The way in which the rail 19 is extended and bent may be changed as appropriate. In the vehicle, the speed of the air flowing under the floor 13 may be changed as appropriate relative to the speed of the air flowing over the roof 16. [Explanation of symbols]

[0047] 11...Bumper 12...Air passage 13...Floor 14…Rear side 15...movable parts 16...Roof 17…road surface 18...Movement mechanism 19...Rail 20...Cart 21...Driver 22...Storage space 23...Wheel 24...Front roller 25...Rear roller 26...Belt 27...Connecting member

Claims

1. An air flow control device for a rear portion of a vehicle that is applied to a vehicle having a bumper at the rear end, in which an air passage is formed above the bumper of the vehicle, and in which air flowing under a floor of the vehicle during travel is directed to the rear side of the rear surface of the vehicle through the air passage, a movable member is disposed in front of the bumper at the rear of the vehicle, and defines the air passage between the movable member and the bumper; The movable member is capable of moving toward or away from the bumper, and changes the cross-sectional area of ​​air flow in the air passage based on this movement.

2. 2. The air flow control device for a rear of a vehicle as described in claim 1, wherein the movable member increases the cross-sectional area of ​​air flow in the air passage by moving away from the bumper when the vehicle speed is equal to or greater than a threshold value compared to when the vehicle speed is less than the threshold value.

3. a rail for guiding the movement of the movable member relative to the bumper; 3. The airflow adjustment device for a rear portion of a vehicle according to claim 1, wherein the movable member moves along the rail to move toward or away from the bumper.

4. the movable member forms the air passage between itself and the bumper so as to extend longitudinally in the width direction of the vehicle; 3. The airflow regulator device for a rear portion of a vehicle according to claim 1, wherein the air passage has a cross-sectional area that is different between a central portion and both end portions in the width direction of the vehicle.

5. 3. The airflow control device for a rear portion of a vehicle according to claim 1, wherein the movable member has a storage space formed therein.

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