Air resistance reducer of vehicle

Abstract

To reduce an air resistance of a vehicle without using a large air blower or an actuator having a special structure.SOLUTION: An outer shell of an air resistance reducer 20 is formed with a housing 21 attached to a vehicle body 11. The housing 21 internally includes an air channel chamber 42. The housing 21 includes a cover wall 22 through which airs A1 and A2 flowing along the vehicle body 11 pass. At least part of the cover wall 22 in a fore-and-aft direction of a vehicle 10 faces the air channel chamber 42. A direction along an upper surface 23 which is an exterior surface of the cover wall 22, that is, a direction orthogonal to the fore-and-aft direction shall be regarded as an orthogonal direction. Part of the cover wall 22 in the orthogonal direction has an air outlet 47 formed to release the air A1a in the air channel chamber 42 outside of the housing 21 or release the air upward so that the air recedes from the air channel chamber 42.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an air resistance reduction device for a vehicle that reduces the air resistance of the vehicle by changing the flow of air flowing along the vehicle body. [Background technology]

[0002] 11, when air A flows from the front to the rear along the roof 102 of the vehicle body 101 of the vehicle 100, vortices V of various sizes are generated near the rear of the vehicle 100. These vortices V cause air resistance to act on the vehicle body 101, pulling the vehicle 100 backward.

[0003] In response to this, various air resistance reduction devices have been devised that reduce air resistance by suppressing the generation of vortices. For example, in the air resistance reduction device described in Patent Document 1, a blower having a linear outlet extending in the vehicle width direction is mounted on the rear of the vehicle. The blower blows air backward from the outlet at a speed equal to or faster than the vehicle speed.

[0004] When the air passing above the vehicle and the air passing below the vehicle mix behind the vehicle, a vortex occurs. However, the air film ejected from the nozzle as described above suppresses the generation of the vortex, thereby reducing the air resistance of the vehicle.

[0005] In addition, in the air resistance reduction device described in Patent Document 2, the flow of air flowing along the vehicle body is controlled by a synthetic jet actuator. This control reduces the air resistance of the vehicle. This actuator periodically drives a vibration unit connected to a vibration plate arranged in a closed space. When the vibration plate is vibrated, air is ejected and sucked from an opening communicating with the closed space. The ejection direction of the air is parallel to the flow direction of the air flowing along the vehicle body. Therefore, the separation point of the boundary layer generated on the wall surface of the vehicle body when the vehicle runs is effectively moved downstream. In addition, the fluctuation of the wake formed at the rear of the vehicle body is suppressed, and the air resistance of the vehicle is reduced. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6031663 [Patent Document 2] Patent No. 5869969 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the air resistance reduction device described in Patent Document 1 requires a large blower that can blow air backward from an outlet at a speed equal to or faster than the vehicle speed. It is not practical to mount such a large blower at the rear of a vehicle. In addition, the air resistance reduction device described in Patent Document 2 requires an actuator with a special structure, such as a synthetic jet actuator. [Means for solving the problem]

[0008] Various aspects of a vehicle air resistance reduction device for solving the above problems will be described below. [Aspect 1] An air resistance reduction device for a vehicle that is provided in a path of air flowing from front to rear along the body of a vehicle and reduces the air resistance of the vehicle by changing the flow of the air, the device comprising a housing that forms an outer shell portion, has an air flow path chamber inside, and is attached to the vehicle body, the housing has a cover wall portion through which air flowing along the vehicle body passes, at least a portion of the cover wall portion in the fore-and-aft direction of the vehicle faces the air flow path chamber, a direction that follows the outer surface of the cover wall portion, and when a direction perpendicular to the fore-and-aft direction is defined as the orthogonal direction, a portion of the cover wall portion in the orthogonal direction has an air outlet that blows air from the air flow path chamber outward from the housing and away from the air flow path chamber.

[0009] According to the above-mentioned configuration, the air flowing from the front to the rear along the body of the vehicle is changed by the air resistance reduction device. It is believed that this change reduces the air resistance of the vehicle in the following manner.

[0010] The air that has flowed along the vehicle body continues to pass through the cover wall. Meanwhile, from an outlet provided in a part of the cover wall in the perpendicular direction, the air flowing through the air flow passage chamber inside the housing is blown out toward a side moving away from the air flow passage chamber. The direction in which the air is blown out from the outlet is a direction intersecting the air flowing along the outer surface of the cover wall. When the air blown out from the outlet hits the air flowing along the outer surface of the cover wall, a small vertical vortex is generated that rotates in a spiral shape and moves rearward. Of the air passing through the cover wall from the front to the rear, the air flowing near the outlet in the perpendicular direction is easily separated from the vehicle body by the vertical vortex, and the straightness is improved.

[0011] In addition, the air flowing along a part of the cover wall in the perpendicular direction where the air outlet is not opened is influenced by the air whose straightness has been increased as described above, and is carried to a point farther rearward from the air resistance reduction device, where it generates small vortices.

[0012] As a result, it is believed that the air resistance acting on the vehicle will be smaller than in a case where the air resistance reduction device is not installed. As described above, the vertical vortex is generated when the air in the air flow passage chamber is blown out from the outlet in a direction intersecting with the air flowing along the outer surface of the cover wall and hits the air. Therefore, the vertical vortex can be generated without blowing air at a speed equal to or faster than the vehicle speed. In addition, the vertical vortex can be generated without using an actuator having a special structure that blows and sucks air by vibrating a vibration plate.

[0013] [Aspect 2] The housing has an inclined wall portion, at least a portion of which faces the air flow path chamber, the inclined wall portion is inclined with respect to the fore-and-aft direction so as to approach the cover wall portion as it approaches the rear, and the rear end portion of the inclined wall portion is located at a portion of the cover wall portion adjacent to the air outlet from the rear side.An air resistance reduction device for a vehicle as described in [Aspect 1].

[0014] According to the above-mentioned configuration, the air in the air passage chamber is guided to the outlet while changing its flow direction by flowing along the inclined wall portion, and is blown out from the outlet toward the outside of the housing and away from the air passage chamber in a direction intersecting with the air flowing along the outer surface of the cover wall portion.

[0015] [Aspect 3] The vehicle air resistance reduction device according to [Aspect 2], wherein the air outlets are opened at a plurality of locations spaced apart from one another in the perpendicular direction of the cover wall portion. According to the above-mentioned configuration, the air in the air flow passage chamber is blown out from the air outlets that are opened at a plurality of positions spaced apart from each other in the perpendicular direction in the cover wall portion, thereby obtaining the effect of reducing the air resistance of the vehicle over a wide area in the perpendicular direction.

[0016] [Aspect 4] An air resistance reduction device for a vehicle as described in [Aspect 3], wherein an intake port is opened in the cover wall portion forward of the air outlet, connecting the outside of the housing with the air flow path chamber and taking in air from outside the housing into the air flow path chamber.

[0017] According to the above configuration, air flow (driving wind) is generated as the vehicle moves. This air flows from the front to the rear along the outer surface of the cover wall. A part of the air flows into the intake port and is taken into the air flow passage chamber. As the taken-in air flows rearward in the air flow passage chamber, it flows along the inclined wall portion, changing its flow direction and is guided to the outlet, from which it is blown out to the outside of the housing. In this way, the driving wind is utilized, and the air flows through the air flow passage chamber and is blown out from the outlet. Note that the blown out air hits air that continues to flow along the outer surface of the cover wall without flowing into the intake port, generating the small vertical vortexes.

[0018] [Aspect 5] An air resistance reduction device for a vehicle as described in [Aspect 4], wherein the intake port extends in a direction inclined with respect to the outer surface of the cover wall portion so as to approach the air flow path chamber toward the rear. According to the above configuration, when the vehicle is traveling, a portion of the air flowing along the outer surface of the cover wall portion flows into the air intake and is taken into the air flow passage chamber. Here, the air intake extends in a direction inclined with respect to the outer surface of the cover wall portion so as to approach the air flow passage chamber toward the rear. Therefore, compared to a case in which the air intake extends in a direction perpendicular to the outer surface, air outside the housing is more likely to flow into the air intake and be taken into the air flow passage chamber.

[0019] [Aspect 6] An air resistance reduction device for a vehicle as described in [Aspect 5], in which an auxiliary protrusion is formed in the cover wall portion adjacent to the rear of the air intake, which protrudes outward from the housing in the direction in which the air intake extends and assists in the intake of the air into the air flow path chamber.

[0020] According to the above configuration, as the vehicle travels, part of the air flowing from the front to the rear along the outer surface of the cover wall hits the auxiliary protrusion and is restricted from flowing further rearward. Therefore, the air flowing along the outer surface of the cover wall is more likely to flow into the air intake than if the auxiliary protrusion were not provided.

[0021] [Aspect 7] A guide wall portion is arranged within the housing, and the guide wall portion has an inclined portion between the air inlet and the inclined wall portion that is inclined with respect to the fore-and-aft direction so as to move away from the cover wall portion as it approaches the rear, thereby guiding the air taken in from the air inlet to the inclined wall portion. An air resistance reduction device for a vehicle described in any one of [Aspect 4] to [Aspect 6].

[0022] According to the above configuration, the air taken into the air flow passage chamber from the intake port flows along the inclined portion of the guide wall portion, and flows in a direction inclined with respect to the fore-and-aft direction so that the air moves away from the cover wall portion as it moves rearward, and is guided to the inclined wall portion.

[0023] [Aspect 8] An air resistance reduction device for a vehicle described in any one of [Aspect 4] to [Aspect 7], wherein the intakes are opened at multiple locations on the cover wall portion spaced apart from each other in the perpendicular direction, and the housing has air flow path sections, each having the air flow path chamber, at multiple locations in the perpendicular direction, and each air flow path section has a pair of opposing wall sections facing each other in the perpendicular direction with the air flow path chamber between them, and a front end of each air flow path chamber is connected to the intake and a rear end of each air flow path chamber is connected to the outlet, and the distance between the pair of opposing wall sections is set to gradually become smaller from the front end to the rear end of the air flow path chamber.

[0024] According to the above configuration, the air that flows into the air inlet and is taken into the air flow passage chamber flows from the front to the rear through the air flow passage chamber, and is guided to the air outlet and blown out from the air outlet. Here, by setting the interval between the adjacent opposing wall portions as described above, the air flow passage chamber's cross-sectional area gradually decreases from the front end to the rear end of the air flow passage chamber. As a result, the flow speed of the air flowing through the air flow passage chamber increases, and the air with the increased flow speed is blown out from the air outlet.

[0025] [Aspect 9] A vehicle air resistance reduction device as described in any one of [Aspect 4] to [Aspect 8], wherein a drain hole is opened at the bottom of the air flow path chamber in the housing, connecting the outside of the housing with the air flow path chamber.

[0026] According to the above configuration, when rain, water produced by melting ice and snow, water used when washing a car, etc. enters the air flow path chamber through at least one of the intake and exhaust ports, the water is discharged to the outside of the housing through a water drain hole opened at the bottom of the air flow path chamber in the housing.

[0027] [Aspect 10] A blower fan is disposed within the housing to blow air from the air flow path chamber and out through the outlet, and a portion of the housing has an intake port which connects the outside of the housing to the air flow path chamber and serves as a passageway through which air outside the housing is drawn into the air flow path chamber as the blower fan operates. The vehicle air resistance reduction device described in [Aspect 2].

[0028] According to the above configuration, when the blower fan is operated, air outside the housing is drawn into the air passage chamber through the intake port. This air is then blown rearward by the blower fan. As this air flows along the inclined wall portion, its flow direction is changed and the air is guided to the outlet port, from which it is blown outward from the housing and away from the air passage chamber.

[0029] [Aspect 11] An air resistance reduction device for a vehicle as described in [Aspect 10], wherein the blower fan is removably positioned within the housing, the housing is removably attached to the vehicle body, the housing has a contact wall portion that contacts the vehicle body when the housing is attached to the vehicle body, and the contact wall portion has an opening through which the blower fan can pass between the inside and outside of the housing when the housing is removed from the vehicle body.

[0030] According to the above configuration, when the housing in which the blower fan is arranged is attached to the vehicle body, the contact wall of the housing comes into contact with the vehicle body. The passage opening opened in the contact wall is blocked by a portion of the vehicle body that comes into contact with the contact wall. The passage opening is hidden by the vehicle body. Therefore, the passage opening is not visible or is difficult to see from outside the vehicle.

[0031] When it becomes necessary to remove the blower fan from the housing for repair, replacement, or the like, the housing in which the blower fan is disposed is removed from the vehicle body. The blower fan is removed from the housing and taken out to the outside of the housing through the passage opening. The repaired blower fan or another blower fan located outside the housing is inserted into the housing through the passage opening and attached to the housing.

[0032] [Aspect 12] An air resistance reduction device for a vehicle as described in [Aspect 10] or [Aspect 11], wherein the inclined wall portion has a drain hole that connects the outside of the housing with the air flow path chamber.

[0033] According to the above configuration, when rain, water produced by melting ice and snow, water used when washing a car, etc. enter the air flow passage chamber through the air outlet, it flows down along the inclined wall portion and is discharged to the outside of the housing through the water drainage hole opened in the inclined wall portion.

[0034] [Aspect 13] An air resistance reduction device for a vehicle described in any one of [Aspect 1] to [Aspect 12], wherein the cover wall portion is formed in a shape extending in the vehicle width direction as the perpendicular direction, and forms the upper end portion of the housing, and the air outlet is opened in a state extending in the vertical direction in a part of the cover wall portion in the vehicle width direction.

[0035] According to the above configuration, the upper end of the housing is formed by a cover wall portion formed in a shape extending in the vehicle width direction. The air outlet is opened at a part of the cover wall portion in the vehicle width direction. The air flow path chamber is located below the cover wall portion. Air in the air flow path chamber is blown out upward through the air outlet. This blown out air acts as described above, changing the flow of air flowing from the front to the rear along the vehicle body, thereby reducing the air resistance of the vehicle. Effect of the Invention

[0036] According to the present invention, it is possible to reduce the air resistance of a vehicle without using a large-sized blower or an actuator having a special structure. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a partial side view illustrating an air flow in a first embodiment in which an air resistance reduction device is provided on a vehicle. [Diagram 2] 1 is a perspective view of an air resistance reduction device according to a first embodiment. [Diagram 3] 1 is a partial vertical cross-sectional view showing an air resistance reduction device according to a first embodiment together with its surrounding parts. [Figure 4] 4 is an enlarged partial vertical sectional view of a portion X in FIG. 3. [Diagram 5] FIG. 3 is a partial perspective view showing one bulging portion in a main body wall portion of the first embodiment. [Figure 6] FIG. 11 is a perspective view of an air resistance reduction device according to a second embodiment. [Figure 7] 7 is a partial vertical cross-sectional view showing an air resistance reduction device according to a second embodiment together with its surrounding parts. FIG. [Figure 8] 5 is a diagram showing an inlet and its surroundings in a modified example, and is a partial vertical cross-sectional view corresponding to FIG. 4. [Figure 9] FIG. 5 is a partial vertical cross-sectional view corresponding to FIG. 4, showing an inlet and its surroundings in a modified example. [Figure 10]FIG. 4 is a diagram corresponding to FIG. 3 and is a partial vertical cross-sectional view showing an air resistance reduction device according to a modified example in which an air inlet is opened at a position different from that of the first embodiment, together with its surrounding area. [Figure 11] FIG. 1 is a partial side view illustrating an air flow in a conventional technology in which an air resistance reduction device is not provided on a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] (First embodiment) Hereinafter, a first embodiment of a device for reducing air resistance for a vehicle will be described with reference to Figs.

[0039] In the following description, the forward direction of the vehicle 10 is referred to as the front, and the backward direction is referred to as the rear. The up-down direction refers to the up-down direction of the vehicle 10, and the left-right direction refers to the vehicle width direction and coincides with the left-right direction when the vehicle 10 is moving forward.

[0040] 1 and 2, the air resistance reduction device 20 is provided in a path of air A that flows from the front to the rear along a vehicle body 11 of a vehicle 10. The air resistance reduction device 20 reduces the air resistance of the vehicle 10 by changing the flow of the air A. The vehicle body 11 here refers to the entire exterior shape (body) of the vehicle 10. The vehicle body 11 includes a roof panel 12 and a back door 13.

[0041] 1 and 3, the air resistance reduction device 20 of the first embodiment is disposed across an upper area of ​​the rear of the roof panel 12 and an upper area of ​​the upper part of the back door 13. As shown in Fig. 3, the air resistance reduction device 20 includes a housing 21 that constitutes an outer shell portion thereof, and a guide wall portion 41 disposed within the housing 21.

[0042] <Housing 21> The housing 21 includes a cover wall portion 22 through which the air A1 passes after flowing along the vehicle body 11, and a main body wall portion 31 disposed below the cover wall portion 22. The housing 21 is attached to the upper portion of the back door 13 by means of screw fastening, attachment using double-sided tape, or the like (not shown).

[0043] [Cover wall 22] Here, the orthogonal direction is a direction along the upper surface 23, which is the outer surface of the cover wall portion 22, and perpendicular to the front-rear direction. In the first embodiment, the orthogonal direction corresponds to the left-right direction. The cover wall portion 22 is formed in a shape that extends at least in the left-right direction. In the first embodiment, the cover wall portion 22 is formed in a shape that extends not only in the left-right direction, but also in a direction that is inclined with respect to the front-rear direction so that it becomes lower toward the rear.

[0044] [Main body wall 31] 3 and 5, the main body wall 31 includes a plate-shaped portion 32 and a plurality of bulging portions 33 having the same configuration. The plate-shaped portion 32 is spaced downward and generally parallel to the cover wall 22. The plurality of bulging portions 33 are disposed on the rear side of the plate-shaped portion 32 and spaced apart from each other in the left-right direction.

[0045] Each bulge 33 bulges downward from the cover wall portion 22 more than the plate-shaped portion 32. The plate-shaped portion 32 and each bulge 33 are connected to each other via a locking portion 34 provided between them. The locking portion 34 is spaced downward from the cover wall portion 22 at a location closer to the cover wall portion 22 than the plate-shaped portion 32.

[0046] Each bulge 33 has air flow passages 35 at multiple locations in the left-right direction (two locations in the first embodiment). Each air flow passage 35 has a pair of opposing wall portions 36 opposed to each other and spaced apart from each other in the left-right direction.

[0047] The two air flow passage sections 35 in each bulging section 33 are connected to each other at least at the front upper end section 33a of the bulging section 33. Behind the front upper end section 33a of each bulging section 33, the two air flow passage sections 35 are separated from each other in the left-right direction.

[0048] The front portion of each bulging portion 33 is configured by a front wall portion 37 that curves so as to bulge gently diagonally downward toward the front. The front wall portion 37 is inclined with respect to the front-rear direction so as to become lower toward the rear side.

[0049] The rear of each air flow passage section 35 is configured with an inclined wall section 38. The inclined wall section 38 is inclined with respect to the front-rear direction so as to approach the cover wall section 22 toward the rear, in this case so as to become higher toward the rear. A rear upper end section 38b, which is the rear end section of the inclined wall section 38 for each air flow passage section 35, is located adjacent to the rear end section 22b of the cover wall section 22 from the rear side.

[0050] An upwardly protruding vertical wall portion 39 is formed on the inclined wall portion 38 of each air flow path portion 35. The vertical wall portion 39 may be formed integrally with the inclined wall portion 38 or may be formed by a separate member. Each vertical wall portion 39 is located at a middle portion of the inclined wall portion 38 in the front-rear direction and at a middle portion in the up-down direction.

[0051] <Guide wall portion 41> As shown in FIG. 3, the guide wall portion 41 is provided for each bulging portion 33. Each guide wall portion 41 has an inclined portion 41a constituting the majority of the guide wall portion 41, a front upper end portion 41b adjacent to the front side of the inclined portion 41a, and a rear lower end portion 41c adjacent to the rear side of the inclined portion 41a. The inclined portion 41a is inclined with respect to the front-rear direction so as to move downward away from the cover wall portion 22 toward the rear, in this case, so as to become lower. The inclined portion 41a is inclined with respect to the front-rear direction at an angle larger than the inclination angle of the cover wall portion 22 with respect to the front-rear direction. The front upper end portion 41b is disposed between the cover wall portion 22 and the locking portion 34, and is locked to the locking portion 34 from above and from the front. The rear lower end portion 41c is locked to the vertical wall portion 39 from above and from the rear.

[0052] <Air flow passage chamber 42> The housing 21 has air flow passage chambers 42 between the cover wall 22 and each bulge 33, the number of which is the same as the number of air flow passage sections 35. A space surrounded by the rear of the cover wall 22, the pair of opposing wall sections 36, the guide wall section 41, and the portion of the inclined wall section 38 that is rearward of the vertical wall section 39 constitutes each air flow passage chamber 42. The two air flow passage chambers 42 in each bulge 33 communicate with each other at the front upper end section 33a of the bulge 33. Therefore, the rear of the cover wall 22, the pair of opposing wall sections 36, the inclined section 41a and the rear lower end section 41c of the guide wall section 41, and the portion of the inclined wall section 38 that is rearward of the vertical wall section 39 all face the air flow passage chamber 42. In addition, each air flow passage chamber 42 is sandwiched from both sides in the left-right direction by the adjacent opposing wall sections 36.

[0053] 3 and 5, the distance D between a pair of opposing walls 36 that face each other in the left-right direction with the air flow passage chamber 42 therebetween is set to gradually decrease from the front end 42a to the rear end 42b of the air flow passage chamber 42. In the first embodiment, both opposing walls 36 are inclined with respect to the front-rear direction so as to approach the other opposing wall 36 toward the rear.

[0054] Here, of the above-mentioned distance D, the distance at the rear end portions of the pair of opposing wall portions 36 is defined as D1. Distance D1 corresponds to the left-right dimension at the rear end portion 42b of each air flow path chamber 42. Of the four opposing wall portions 36 in the same bulging portion 33, the distance at the front end portions of the two opposing wall portions 36 located outermost in the left-right direction is defined as D2. Distance D2 has a value greater than twice distance D1.

[0055] 2 and 3, the air resistance reduction device 20 has an inlet 45 and an outlet 47. The inlet 45 is a location where a portion of the air A1 outside the housing 21 is taken in as air A1a into the air flow path chamber 42. The outlet 47 is a location where the air A1a in the air flow path chamber 42 is blown out to the outside of the housing 21, toward the upper side away from the air flow path chamber 42.

[0056] <Outlet 47> The air outlet 47 is opened at the rear end 22b of the cover wall portion 22 at a position above the rear end 42b of each air flow passage chamber 42. Each air outlet 47 extends in the vertical direction and is connected to the rear end 42b of the air flow passage chamber 42. In other words, each air flow passage chamber 42 is connected to the outside of the housing 21 via the air outlet 47. Each air outlet 47 is located adjacent to the front side of the rear upper end 38b of the inclined wall portion 38.

[0057] As described above, two air flow passages 35 are provided for each bulge portion 33, and therefore two air outlets 47 are opened above each bulge portion 33. The two air outlets 47 are spaced apart from each other in the left-right direction. As described above, the multiple bulge portions 33 are arranged in the main body wall portion 31 while being spaced apart from each other in the left-right direction. Therefore, the air outlets 47 are opened at multiple locations spaced apart from each other in the left-right direction of the cover wall portion 22, and in the first embodiment, the number of locations is twice the number of the bulge portions 33.

[0058] Here, assuming that the dimension of each air outlet 47 in the left-right direction is L1, the dimension L1 is set to a value approximately equal to the above-mentioned interval D1 (see FIG. 5). <Intake port 45> As shown in Figs. 3 and 5, the two air flow passage sections 35 in each bulging section 33 are connected at least at the front upper end 33a of the bulging section 33. The inlet 45 is opened at a location above the front upper end 33a in the cover wall section 22. The location where the inlet 45 is opened is a location spaced forward from the air outlet 47. The location where the inlet 45 is opened is a location above the boundary between the inclined section 41a and the front upper end 41b. Each inlet 45 is connected to the front end 42a of the air flow passage chamber 42. In other words, each air flow passage chamber 42 is connected to the outside of the housing 21 via the inlet 45.

[0059] 2 and 3, the intake openings 45 are provided in the cover wall 22, one at a time, at a position above the front upper end 33a of each bulge 33. As described above, the multiple bulges 33 are arranged in the main body wall 31 while being spaced apart from each other in the left-right direction. Therefore, the intake openings 45 are opened at multiple positions spaced apart from each other in the left-right direction of the cover wall 22, the same number of positions as the number of the bulges 33 in the first embodiment.

[0060] Here, assuming that the dimension of each intake port 45 in the left-right direction is L2, the dimension L2 is set to a value approximately equal to the above-mentioned interval D2 (see FIG. 5). Each intake port 45 has a shape longer in the left-right direction than each air outlet 47.

[0061] 4, each intake port 45 extends in a direction inclined relative to the front-rear direction so as to approach the air flow path chamber 42 toward the rear. In the first embodiment in which the cover wall portion 22 having each intake port 45 is located above the air flow path chamber 42, each intake port 45 extends in a direction inclined relative to the upper surface 23 of the cover wall portion 22 so as to become lower toward the rear.

[0062] Here, assuming that the extension direction of each intake port 45 forms an angle θ with respect to the upper surface 23 of the cover wall portion 22, the angle θ is set to 30° or less. In other words, the angle θ is the angle that the front inner wall surface 45a of the intake port 45 forms with respect to the upper surface 23.

[0063] The inner wall surface 45a is connected to an upper surface of the inclined portion 41a. The angle that the inner wall surface 45a forms with respect to the front-rear direction is approximately the same as the angle that the inclined portion 41a forms with respect to the front-rear direction. <Drain hole 49> 3, a drain hole 49 that connects each air flow passage chamber 42 to the outside of the housing 21 is opened at a location that is the bottom of each air flow passage chamber 42 in the housing 21. In the first embodiment, the drain hole 49 for each air flow passage chamber 42 is opened at a location adjacent to the rear side of the vertical wall portion 39 in the inclined wall portion 38 of each air flow passage section 35. Each drain hole 49 extends in the vertical direction.

[0064] The air resistance reduction device 20 of the first embodiment is configured as described above. Next, the operation of the first embodiment will be described. As shown in Figures 1 and 2, when a vehicle 10 is traveling, a flow of air A (traveling wind) is generated above the vehicle body 11 (roof panel 12) as the vehicle travels. This air A flows from the front to the rear relative to the roof panel 12. The flow of air A is changed by the air resistance reduction device 20 of the first embodiment. It is believed that this change reduces the air resistance of the vehicle 10 in the following manner.

[0065] The air A that flows along the roof panel 12 passes through the cover wall portion 22. As shown in Figures 1 and 3, this air A includes air A1 that flows through a portion corresponding to the air outlet 47 in the left-right direction and air A2 that flows through a portion not corresponding to the air outlet 47. The air A1 includes air A1a that flows into the air inlet 45 and air A1b that passes above the air inlet 45 without flowing in.

[0066] One intake port 45 is provided for each bulging portion 33. The bulging portions 33 are provided at multiple locations in the left-right direction. Therefore, the air A1a flows into each of the intake ports 45 opened at multiple locations in the left-right direction of the cover wall portion 22. Also, since each intake port 45 has an elongated shape in the left-right direction, a larger amount of air A1a flows into each intake port 45.

[0067] The air A1a flowing into each intake port 45 passes through the front upper end portion 33a of the bulging portion 33 located below the intake port 45. The two air flow passage chambers 42 in each bulging portion 33 are connected at the front upper end portion 33a. Therefore, the air A1a passing through the front upper end portion 33a is divided into two in the left-right direction and taken into the corresponding one of the two air flow passage chambers 42.

[0068] Here, the air inlet 45 extends in a direction inclined with respect to the front-rear direction and the upper surface 23 of the cover wall portion 22 so as to approach the air flow passage chamber 42 toward the rear, i.e., to become lower. Therefore, the air A1a flows into the air inlet 45 and is easily taken into each air flow passage chamber 42.

[0069] Moreover, as the angle θ that the extension direction of each inlet 45 makes with respect to the top surface 23 increases, it becomes more difficult for the air A1a to flow into the inlet 45. In the first embodiment in which the angle θ is set to 30° or less, the air A1a easily flows into the inlet 45.

[0070] As described above, the air A1a that flows into each intake port 45 and is taken into each air flow passage chamber 42 flows through the air flow passage chamber 42 from the front to the rear, and is guided to the air outlet 47. More specifically, the air A1a flows along the inclined portion 41a of the guide wall portion 41, and flows in a direction inclined relative to the front-to-rear direction and the upper surface 23 of the cover wall portion 22, so that the air A1a moves away from the cover wall portion 22 as it moves rearward, i.e., becomes lower, and is guided to the inclined wall portion 38.

[0071] This air A1a flows along the inclined wall portion 38, and is guided to the air outlet 47 while changing its flow direction. The air A1a is blown out from the air outlet 47 to the outside of the housing 21, toward the upper side away from the air flow passage chamber 42. This blowing direction intersects with the air A1b passing above the air outlet 47 without flowing into the inlet 45.

[0072] Here, the distance D between the adjacent opposing wall portions 36 gradually decreases from the front end portion 42a to the rear end portion 42b of the air flow passage chamber 42 (see FIG. 5). As a result, the flow passage cross-sectional area of ​​the air flow passage chamber 42 gradually decreases from the front end portion 42a to the rear end portion 42b of the air flow passage chamber 42. Accordingly, the flow velocity of the air A1a flowing through the air flow passage chamber 42 increases, and the air A1a with the increased flow velocity is blown out from the air outlet 47.

[0073] Two air outlets 47 are provided for each bulging portion 33. The bulging portions 33 are provided at multiple locations in the left-right direction. Therefore, the air A1a is blown out from each of the air outlets 47 opened at multiple locations in the left-right direction of the cover wall portion 22. The air A1a is blown out over a wide area in the left-right direction.

[0074] When air A1a blown upward from the air outlet 47 hits air A1b passing above the air outlet 47 without flowing into the inlet 45, a small vertical vortex V2 is generated that rotates in a spiral shape and moves backward, as shown in Fig. 1. The air A1b is easily separated from the vehicle body 11 by the vertical vortex V2. As a result, the straightness of the air A1b is improved.

[0075] Furthermore, the air A2 that flows along a portion of the cover wall portion 22 in the left-right direction that is not open to the air outlet 47 is influenced by the air A1b whose straightness has been improved as described above. The air A2 is carried to a location farther rearward from the air resistance reduction device 20, and generates a vortex V3 that is smaller than the vortex V (see FIG. 11) that occurs when the air resistance reduction device 20 is not installed.

[0076] As a result, it is believed that the air resistance acting on the vehicle 10 will be smaller than in a case where the air resistance reduction device 20 is not installed. However, rain, water produced by melting ice and snow, water used in washing a car, etc. may enter the air flow passage chamber 42 from at least one of the inlet 45 and the outlet 47. When the water W enters from the inlet 45, the water W flows down along the guide wall portion 41 and is discharged to the outside of the housing 21 from the water drainage hole 49 as shown by the two-dot chain line in Fig. 3. When the water W enters from the outlet 47, the water W flows down along the inclined wall portion 38 and is discharged to the outside of the housing 21 from the water drainage hole 49 as shown by the two-dot chain line in Fig. 3. At this time, even if the water W flows vigorously downward and forward along the inclined wall portion 38, the water W hits the vertical wall portion 39 and changes its flow direction downward, and is discharged from the water drainage hole 49.

[0077] Next, the effects of the first embodiment will be described. (1-1) As shown in FIG. 3, in the first embodiment, an air outlet 47 is opened in a portion of the cover wall portion 22 in the left-right direction, through which air A1a in the air flow path chamber 42 is blown outwardly of the housing 21, toward the upper side, away from the air flow path chamber 42.

[0078] Therefore, a vertical vortex V2 can be generated by the air A1a blown out from the air outlet 47. Of the air A passing through the cover wall portion 22 from the front to the rear, the air A1b passing above the air outlet 47 can be easily separated from the vehicle body 11 by the vertical vortex V2, thereby improving the straightness of the air A1b. In addition, a small vortex V3 can be generated at a location away from the air resistance reduction device 20 to the rear by the air A2 that flows through a portion of the upper surface 23 where the air outlet 47 is not opened and is influenced by the air A1b whose straightness has been improved as described above. As a result, the air resistance of the vehicle 10 can be reduced.

[0079] Here, as described above, the vertical vortex V2 is generated when the air A1a is blown upward from the air outlet 47 and hits the air A1b flowing along the upper surface 23 of the cover wall portion 22. Therefore, unlike Patent Document 1, the vertical vortex V2 can be generated without blowing air at a speed equal to or faster than the vehicle speed. Also, unlike Patent Document 2, the vertical vortex V2 can be generated without using an actuator having a special structure that vibrates a vibration plate to blow and suck air.

[0080] (1-2) As shown in Fig. 3, in the first embodiment, an inclined wall portion 38 that is inclined in the front-rear direction so as to approach the cover wall portion 22 toward the rear is formed at a location facing the air flow path chamber 42 at the rear of each air flow path portion 35. Then, a rear upper end portion 38b of the inclined wall portion 38 is positioned at a location of the cover wall portion 22 adjacent to the air outlet 47 from the rear side.

[0081] Therefore, by making the air A1a in the air flow passage chamber 42 flow along the inclined wall portion 38, the air A1a can be guided to the air outlet 47 while changing its flow direction, and can be blown out upward from the air outlet 47.

[0082] (1-3) As shown in Fig. 2, in the first embodiment, the air outlets 47 are opened at a plurality of locations spaced apart from each other in the left-right direction of the cover wall portion 22. Therefore, the effect of reducing the air resistance of the vehicle 10 described above in (1-1) can be obtained over a wide area in the left-right direction.

[0083] (1-4) As shown in FIGS. 2 and 3, in the first embodiment, the intake port 45 is opened at a position in front of the air outlet 47 in the cover wall portion 22. Therefore, air A1a that constitutes a part of the running wind can be caused to flow into the intake port 45 and taken into the air flow passage chamber 42. The taken-in air A1a can be caused to flow from the front to the rear in the air flow passage chamber 42 and blown out from the blowing port 47. In this way, the running wind can be used to cause the air A1a to flow within the air flow passage chamber 42, and the air A1a can be blown out from the blowing port 47. Therefore, it is not necessary to separately provide a means (power source) for generating a flow of air A1a in the air flow passage chamber 42.

[0084] (1-5) As shown in FIG. 4, in the first embodiment, the air inlet 45 extends in a direction inclined with respect to the upper surface 23 of the cover wall portion 22 so as to approach the air flow passage chamber 42 toward the rear, i.e., so as to become lower.

[0085] Therefore, compared to a case where the intake port 45 extends in a direction perpendicular to the upper surface 23, the air A1a can be made to flow into the intake port 45 and can be more easily taken into the air flow path chamber . (1-6) As shown in Fig. 4, in the first embodiment, the angle θ that the extension direction of the intake port 45 makes with respect to the upper surface 23 is set to be equal to or less than 30°. Therefore, it becomes easier to obtain the effect of (1-5) above, that is, to make it easier for the air A1a to flow into the intake port 45 and to be taken into the air flow path chamber 42.

[0086] (1-7) As shown in Fig. 3, in the first embodiment, a guide wall portion 41 is provided in each air flow path portion 35. The guide wall portion 41 is provided with an inclined portion 41a that is inclined in the front-rear direction so as to move downward away from the cover wall portion 22 toward the rear, i.e., so as to become lower.

[0087] Therefore, the air A1a taken in from the intake port 45 to the front end portion 42a of the air flow passage chamber 42 can be guided to the inclined wall portion 38 described above in (1-2) by flowing along the inclined portion 41a.

[0088] (1-8) As shown in Fig. 2 and Fig. 3, in the first embodiment, in addition to the air outlet 47 of (1-3), the air inlets 45 are opened at a plurality of positions spaced apart from each other in the left-right direction of the cover wall 22. The housing 21 has air flow passage sections 35, each having an air flow passage chamber 42, at a plurality of positions in the left-right direction. Each air flow passage section 35 has a pair of opposing wall sections 36 that face each other in the left-right direction with the air flow passage chamber 42 sandwiched therebetween. The front end section 42a of each air flow passage chamber 42 is connected to the air inlets 45, and the rear end section 42b of each air flow passage chamber 42 is connected to the air outlet 47. The distance D between the pair of opposing wall sections 36 is gradually reduced from the front end section 42a to the rear end section 42b of the air flow passage chamber 42.

[0089] Therefore, the flow velocity of the air A1a in the air flow passage chamber 42 can be increased, and then the air A1a can be blown out from the air outlet 47. (1-9) As shown in FIG. 3, in the first embodiment, the water drain hole 49 is opened at the bottom of the air flow passage chamber 42 in the housing 21. Therefore, it is possible to prevent water W from accumulating in the air flow passage chamber 42. It is possible to prevent phenomena caused by the accumulation of water W, such as the water W adhering to electrical components (not shown) and affecting their operation, the accumulated water W shaking and generating abnormal noise, and the accumulated water W freezing. In addition, it is possible to prevent the volume of the air flow passage chamber 42 from being reduced by the amount of the accumulated water W, which reduces the effect of reducing air resistance. In addition, it is possible to prevent the accumulated water W from dripping when the back door 13 is opened or closed.

[0090] (1-10) Active rear roof spoilers and vortex generators are known as devices that suppress the generation of vortices and reduce air resistance. The active real roof spoiler is a type of real roof spoiler that is attached to the rear end of the roof of a vehicle, and has a movable part that operates in two different forms depending on the vehicle speed. When the vehicle speed exceeds a certain value, the movable part extends rearward from the vehicle body. Therefore, the air flowing along the roof of the vehicle body is guided rearward by the movable part, which increases the straightness of the air and prevents it from generating vortices near the rear of the vehicle. Small vortices are generated at points farther rearward from the vehicle, which reduces the vehicle's air resistance.

[0091] The vortex generator is a vortex generator, and is provided, for example, on a real roof spoiler. The vortex generator includes protrusions protruding upward from a plurality of locations on the upper surface of the real roof spoiler that are spaced apart in the vehicle width direction, and a location on the upper surface of the real roof spoiler that is adjacent to the protrusions in the vehicle width direction. A portion of the air that flows along the roof of the vehicle body is changed in flow direction upward by the protrusions. Another portion of the air that flows along the roof of the vehicle body flows rearward along the upper surface of the real roof spoiler. These two flows suppress the generation of vortices near the rear of the vehicle. Therefore, in this case as well, small vortices are generated at locations farther rearward from the vehicle, thereby reducing the air resistance of the vehicle.

[0092] In the above-mentioned active real roof spoiler, the movable part is located outside the real roof spoiler. In the vortex generator, multiple protrusions are located outside the real roof spoiler. Therefore, both of these have an effect on the design of the real roof spoiler and, ultimately, the vehicle.

[0093] In contrast, in the first embodiment, the air outlet 47, which has the same effect as that achieved by the movable portion and the protrusion, is not provided outside the housing 21. The air outlet 47 is difficult to see from outside the vehicle 10. Therefore, it is possible to prevent the design of the vehicle 10 from being impaired by the provision of the air resistance reduction device 20.

[0094] Second embodiment Next, a second embodiment of the vehicle air resistance reduction device will be described with reference to FIGS.

[0095] 7, in the second embodiment, the number of bulging portions 33 in the main body wall portion 31 is changed to one. Also, the number of air flow path chambers 42 in the bulging portion 33 is changed to one.

[0096] The rear half of the bulging portion 33 is constituted by the inclined wall portion 38, and the front half of the bulging portion 33 is constituted by the front wall portion 37. The front wall portion 37 has a flat contact wall portion 37a in a part thereof. In the second embodiment, the contact wall portion 37a is located at the boundary portion of the front wall portion 37 with the inclined wall portion 38. The contact wall portion 37a is inclined so as to become higher toward the front side. When the housing 21 is attached to the vehicle body 11, the contact wall portion 37a contacts a part of the vehicle body 11, that is, the upper end portion 13a of the back door 13 in the second embodiment. The upper end portion 13a is formed flat, and like the contact wall portion 37a, is inclined so as to become higher toward the front side.

[0097] The space surrounded by the bulging portion 33 (the inclined wall portion 38 and the front wall portion 37) and a portion of the cover wall portion 22 located above the bulging portion 33 constitutes an air flow path chamber 42. In the second embodiment, most of the inclined wall portion 38 faces the air flow path chamber 42.

[0098] In the second embodiment, the intake port 45 is omitted. Accordingly, the guide wall portion 41 is omitted. In addition, the locking portion 34 is omitted from the main body wall portion 31. As shown in Fig. 6 and Fig. 7, the air outlet 47 is opened at a rear end portion 22b of the cover wall portion 22, in a plurality of positions spaced apart from each other in the left-right direction, similarly to the first embodiment.

[0099] 7, a blower fan 50 having a general structure and blowing air from the front to the rear is disposed in the central portion in the front-to-rear direction within the air flow passage chamber 42. The blower fan 50 is located forward of the air outlet 47.

[0100] An intake port 51 that communicates between the outside of the housing 21 and the air flow passage chamber 42 is opened in a location in front of the blower fan 50 in the housing 21. The intake port 51 corresponds to the intake port 45 in the first embodiment, and serves as a passage through which air A3 outside the housing 21 is drawn into the air flow passage chamber 42 as the blower fan 50 operates.

[0101] The blower fan 50 is removably disposed within the housing 21 via a detachable part 52 . The housing 21 is removably attached to the vehicle body 11 (the upper part of the back door 13) by screw fastening or the like as described in the first embodiment. The housing 21 is attached to the back door 13 with the contact wall portion 37a of the front wall portion 37 in contact with the upper end portion 13a of the back door 13, as described above.

[0102] The contact wall portion 37a has an opening 54. The opening 54 is formed in a size and shape that allows the blower fan 50 and the detachable part 52 to pass through when the housing 21 is removed from the back door 13.

[0103] Furthermore, in the housing 21, at a position lower than the air outlet 47, a water drain hole 49 that communicates between the outside of the housing 21 and the air flow passage chamber 42 is opened. In the second embodiment, the water drain hole 49 is opened in a position of the inclined wall portion 38, between the blower fan 50 and the air outlet 47, and closer to the blower fan 50. In the inclined wall portion 38, at a position adjacent to the front side of the water drain hole 49, a vertical wall portion 39 that protrudes upward is formed.

[0104] The configuration other than the above is the same as that of the first embodiment. Therefore, in the second embodiment, the same elements as those described in the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted. Next, the operation of the second embodiment will be described.

[0105] When the housing 21 in which the blower fan 50 is arranged is attached to the vehicle body 11, the contact wall portion 37a contacts the upper end portion 13a of the back door 13. The passage opening 54 opened in the contact wall portion 37a is blocked by the portion of the back door 13 that contacts the contact wall portion 37a. The passage opening 54 is hidden by the back door 13.

[0106] When the vehicle 10 is traveling, a flow of air A (traveling wind) is generated as the vehicle travels. This air A flows from the front to the rear of the vehicle body 11. The flow of air A is changed by the air resistance reduction device 20. It is believed that this change reduces the air resistance of the vehicle 10 in the following manner.

[0107] The air A that flows along the vehicle body 11 passes through the cover wall portion 22. This air A includes air A1 that flows through a portion corresponding to the air outlet 47 in the left-right direction, and air A2 that flows through a portion not corresponding to the air outlet 47.

[0108] When the blower fan 50 is operated, air A3 outside the housing 21 is drawn into the air flow passage chamber 42 through the suction port 51. The air A3 is blown rearward by the blower fan 50.

[0109] The air A3 flows along the inclined wall portion 38, changing its flow direction and being guided to the outlet 47, from which it is blown outward from the housing 21 toward the upper side, away from the air flow passage chamber 42.

[0110] Here, the air outlets 47 are provided at multiple positions in the left-right direction of the cover wall portion 22. Therefore, the air A3 is blown out from each of the air outlets 47 opened at multiple positions in the left-right direction of the cover wall portion 22. The air A3 is blown out over a wide area in the left-right direction.

[0111] 1, air A3 blown upward from each air outlet 47 flows along the upper surface 23 of the cover wall portion 22 and hits air A1 passing above the air inlet 45, generating small vertical vortices V2. The air A1 is easily separated from the vehicle body 11 by the vertical vortices V2. As a result, the straightness of the air A1 is improved.

[0112] Moreover, the air A2 flowing along the upper surface 23 of the cover wall portion 22 in the left-right direction and along a portion where the air outlet 47 is not opened is affected by the air A1 whose straightness has been improved as described above. The air A2 is carried to a portion farther rearward from the air resistance reduction device 20, where it generates a small vortex V3.

[0113] As a result, similarly to the above-described first embodiment, it is considered that the air resistance acting on the vehicle 10 is also reduced according to the second embodiment, compared to a case in which the air resistance reduction device 20 is not mounted.

[0114] Incidentally, when it becomes necessary to remove the blower fan 50 from the housing 21 to the outside of the housing 21 for repair, replacement, or the like, the housing 21 in which the blower fan 50 is disposed is removed from the vehicle body 11 (back door 13). When the blower fan 50 is removed from the housing 21, the blower fan 50 is taken out to the outside of the housing 21 through the passage opening 54. Thereafter, the repaired blower fan 50 or another blower fan 50 located outside the housing 21 is put into the housing 21 through the passage opening 54 and attached to the housing 21 via the detachable part 52.

[0115] 7, when rain, water produced by melting ice and snow, water used in washing a car, or the like enters the air flow passage chamber 42 from the air outlet 47, the water W flows down along the inclined wall portion 38. The water W is discharged to the outside of the housing 21 through the water drainage holes 49. At this time, even if the water W that entered through the air outlet 47 flows vigorously downward and forward along the inclined wall portion 38, the water W hits the vertical wall portion 39 and has its flow direction changed downward, and is discharged through the water drainage holes 49.

[0116] Therefore, according to the second embodiment, it is possible to obtain the same effects as those (1-1), (1-2), (1-3), and (1-10) in the first embodiment. In addition to the above, the second embodiment also obtains the following effect.

[0117] (2-1) In the second embodiment, a blower fan 50 is disposed inside the housing 21. An intake port 51 is opened in a part of the housing 21. The intake port 51 connects the outside of the housing 21 with the air flow passage chamber 42 and serves as a passage through which air A3 outside the housing 21 is drawn into the air flow passage chamber 42 as the blower fan 50 operates.

[0118] Therefore, by operating the blower fan 50, a flow of air A3 from the intake port 51 toward the air outlet 47 is generated in the air flow passage chamber 42, and the air A3 can be blown upward from the air outlet 47.

[0119] (2-2) In the second embodiment, the blower fan 50 is removably disposed inside the housing 21. The housing 21 is removably attached to the vehicle body 11 (back door 13). The housing 21 is provided with a contact wall portion 37a that comes into contact with the upper end portion 13a of the back door 13 when the housing 21 is attached to the back door 13. The contact wall portion 37a has an opening 54 for allowing the blower fan 50 to pass between the inside and outside of the housing 21 when the housing 21 is detached from the back door 13.

[0120] Therefore, when the housing 21 in which the blower fan 50 is arranged is attached to the back door 13, the passage opening 54 can be hidden by the upper end portion 13a of the back door 13. This prevents the passage opening 54 from being visible from the outside of the vehicle 10, thereby preventing the appearance from being deteriorated.

[0121] Furthermore, when it becomes necessary to remove the blower fan 50 inside the housing 21 to the outside of the housing 21, the housing 21 in which the blower fan 50 is disposed is removed from the back door 13. Then, the blower fan 50 can be removed to the outside of the housing 21 through the passage opening 54. Thereafter, a repaired or different blower fan 50 can be inserted into the housing 21 through the passage opening 54 and attached to that housing 21.

[0122] In this way, according to the second embodiment, it is possible to achieve both improved appearance and ease of replacement and repair of the blower fan 50. (2-3) In the second embodiment, the water drainage hole 49 is opened in the housing 21 at a position lower than the air outlet 47. Therefore, similar to the above (1-9) in the first embodiment, it is possible to prevent the water W from accumulating in the air flow passage chamber 42.

[0123] The above embodiment can also be implemented as modified examples as follows: The above embodiment and the following modified examples can be implemented in combination with each other within a range that does not cause technical contradiction.

[0124] <Matters Concerning the Cover Wall 22> The entire cover wall portion 22 in the front-rear direction may face the air flow passage chamber 42 . <Matters related to the air flow passage portion 35> Only one of the opposing wall portions 36 may be inclined in the front-to-rear direction, provided that the distance D between the pair of opposing wall portions 36 in the first embodiment gradually decreases from the front end portion 42a to the rear end portion 42b of the air flow path chamber 42.

[0125] In the first embodiment, three or more air flow passage sections 35 may be provided for each bulging section 33 . <Matters regarding the inclined wall portion 38> In the first embodiment, the entire inclined wall portion 38 may face the air flow passage chamber 42 .

[0126] The inclined wall portion 38 does not necessarily have to be inclined in the front-rear direction so as to approach the cover wall portion 22 toward the rear. <Matters Concerning the Guide Wall 41> In the first embodiment, the guide wall portion 41 can be omitted as appropriate.

[0127] <Matters regarding intake port 45> In order to make it easier to take in the air A1a into the air flow passage chamber 42, the shape of a portion of the cover wall portion 22 adjacent to the rear of the intake port 45 may be modified. Figures 8 and 9 show one example of such a modification.

[0128] In the modified example of FIG. 8, the cover wall portion 22 has an extension portion 55 formed at the upper end portion adjacent to the intake port 45 on the rear side thereof, the extension portion 55 extending forward. 9, an auxiliary protrusion 56 is formed in the cover wall portion 22 at a location adjacent to the rear of the intake port 45. The auxiliary protrusion 56 protrudes from the location toward the side away from the air flow path chamber 42 in the extension direction of the intake port 45, i.e., obliquely forward and upward, to assist in the intake of air A1a into the air flow path chamber 42.

[0129] 9, when the vehicle 10 is traveling, a portion of the air A1 (air A1a) flowing from the front to the rear along the upper surface 23 of the cover wall portion 22 hits the auxiliary protrusion 56 and is restricted from flowing further rearward. Therefore, the air A1a is more likely to flow into the intake port 45 than when the auxiliary protrusion 56 is not provided.

[0130] If the intake port 45 is blocked by foreign objects such as pine needles or garbage, or if the intake port 45 is blocked by snow, the effect of reducing air resistance may be reduced. Also, if the snow blocking the intake port 45 melts and turns into water, the water may cause abnormal noise. Therefore, a movable lid that opens and closes the intake port 45 may be added, and the movable lid may be opened and closed depending on the situation.

[0131] For example, when there is a high possibility that the inlet 45 will be blocked by foreign objects, snow, etc., the movable lid may be closed. This can prevent the inlet 45 from being blocked by foreign objects or snow. In addition, it can prevent abnormal noise caused by melting snow.

[0132] Such modifications may be made to the outlet 47 . The addition of the intake 45 may cause abnormal noise from the intake 45, resulting in a decrease in quietness. Therefore, the shape of the intake 45 may be changed to one that is less likely to cause abnormal noise, for example, a shape that has projections and recesses.

[0133] Furthermore, the cross-sectional shapes of the upper and lower peripheral edges of intake 45 may be curved in an arc shape so as to bulge inwardly of intake 45. In this way, the flow direction of air can be smoothly changed when it flows into intake 45, and the generation of abnormal noise can be suppressed.

[0134] Such modifications may be made to the outlet 47 . For example, the air inlet 45 may be configured with a mesh structure, a lattice structure, or the like. According to this modification, it is possible to prevent a person's fingers from entering the air inlet 45 while allowing air to pass through. Such a modification may also be made to the air outlet 47.

[0135] The air inlet 45 may be opened at a position different from that in the first embodiment. Fig. 10 shows one example. In this modified example, the air inlet 45 is opened at the inclined wall portion 38. A cylindrical air flow path portion 58 having an air flow path chamber 57 is provided inside the housing 21. The air flow path portion 58 is provided as a part of the cover wall portion 22, but may be provided as a separate member. The air inlet 45 and the air outlet 47 are in communication with each other via the air flow path portion 58.

[0136] According to this modification, when a vortex V4 occurs below the inclined wall portion 38 as the vehicle 10 travels, the air A4 forming the vortex V4 is taken into the air flow passage chamber 57 from the intake port 45. The air A4 can then be guided by the air flow passage chamber 57 to the air outlet 47 and blown upward from the air outlet 47 (see FIG. 1). In this case as well, it is believed that the same effects as those of the first embodiment can be obtained.

[0137] In the above modification, since the intake port 45 functions as a drain hole, there is no need to provide a separate drain hole. The extending direction of the intake port 45 does not have to be inclined with respect to the outer surface of the cover wall portion 22 so that the intake port 45 approaches the air flow passage chamber 42 toward the rear.

[0138] <Matters related to air outlet 47> The number of the air outlets 47 may be changed to a number different from that in the first and second embodiments, provided that the air outlets 47 are provided in a part of the cover wall portion 22 in the orthogonal direction (left-right direction). The minimum number of the air outlets 47 that can be provided is "1".

[0139] In the first and second embodiments, the direction in which the air outlet 47 extends may be vertical, or may be inclined with respect to the vertical. <Matters regarding drain hole 49> In the first and second embodiments, the water drainage holes 49 may be provided in multiple locations.

[0140] In the first and second embodiments, when water W flows into the air passage chamber 42, the water may be drained using a structure different from the water drain hole 49. A mesh may be attached to the drainage holes 49.

[0141] The portion of the housing 21 where the drainage holes 49 are provided may be formed with a mesh structure or a lattice structure instead of the drainage holes 49. <Matters regarding the blower fan 50> The blower fan 50 may be a so-called waterproof fan in which electronic components including a circuit board and the like are covered with resin.

[0142] In the second embodiment, a plurality of blower fans 50 may be arranged in the air flow passage chamber . In the second embodiment, the main body wall 31 may have a plurality of, for example, two, bulging portions 33 in the left-right direction. Each bulging portion 33 may have one air flow path chamber 42. In this case, a blower fan 50 may be provided for each air flow path chamber 42.

[0143] <Other matters> If the water W that has entered the air flow passage chamber 42 drips from the middle part of the housing 21 in the left-right direction, the vehicle body 11 (back door 13) may become dirty. In this case, the appearance of the back door 13 may be deteriorated, and rear visibility through the back door 13 may be reduced. Therefore, the housing 21 may be provided with a structure that guides the water W in the air flow passage chamber 42 to both outer parts in the left-right direction. According to this modification, the water W can be caused to drip from both the left and right sides of the housing 21, so that the deterioration of the appearance and rear visibility described above can be suppressed.

[0144] The contact wall portion 37a may be formed in a shape different from that of the second embodiment, provided that the shape is such that the contact wall portion 37a comes into contact with the vehicle body 11 when the housing 21 is attached to the vehicle body 11. The air resistance reduction device 20 of the present invention may be provided in a location different from that in the first and second embodiments, provided that it is located in the path of the air A that flows along the vehicle body 11 from front to rear in the longitudinal direction of the vehicle 10.

[0145] The air resistance reduction device 20 may be provided, for example, at the rear of the bonnet, the rear end of the roof, the rear end of the trunk, etc. In these cases, the vehicle width direction (left-right direction) corresponds to the orthogonal direction. The air outlet is opened in a part of the cover wall in the vehicle width direction (left-right direction). The air outlet extends in the vertical direction, similar to the first and second embodiments.

[0146] The air resistance reduction device 20 may be provided, for example, around the front fender, around the side mirror, around the C-pillar, around the side of the rear lamp, at the rear end of the rear fender, etc. In these cases, the vertical direction corresponds to the orthogonal direction. The air outlet is opened in a part of the cover wall in the vertical direction. The air outlet extends in the vehicle width direction (left and right direction). Air is blown outward in the vehicle width direction from the air outlet. [Explanation of symbols]

[0147] 10…Vehicle 11…Body 20…Air resistance reduction device 21. Housing 22…Cover wall 23...Top surface (outer surface) 35,58…Air flow path section 36…Facing wall 37a...Contact wall part 38…Slanted wall part 38b...Rear upper end portion (rear end portion of inclined wall portion) 41...Guide wall section 41a...Slope part 42,57...Air flow passage chamber 42a...front end 42b...Rear end 45…Intake port 47…Air outlet 49…Drain hole 50…Ventilation fan 51…Intake port 54... Passage gate 56…Auxiliary protrusion A, A1, A1a, A1b, A2, A3, A4...Air D,D1,D2…interval

Claims

1. An air resistance reduction device for a vehicle, the device being provided in a path of air flowing from a front to a rear along a body of the vehicle, and reducing the air resistance of the vehicle by changing the flow of the air, a housing that constitutes an outer shell portion, has an air flow passage chamber therein, and is attached to the vehicle body; The housing includes a cover wall through which air flowing along the vehicle body passes, At least a portion of the cover wall portion in the front-rear direction of the vehicle faces the air flow path chamber, When a direction along the outer surface of the cover wall portion and perpendicular to the front-rear direction is defined as an orthogonal direction, An air resistance reduction device for a vehicle, wherein a portion of the cover wall portion in the perpendicular direction has an air outlet opening for blowing air in the air flow path chamber outward from the housing and away from the air flow path chamber.

2. The housing includes an inclined wall portion at least a portion of which faces the air flow passage chamber, The inclined wall portion is inclined with respect to the front-rear direction so as to approach the cover wall portion toward the rear, The device for reducing air resistance for a vehicle according to claim 1 , wherein a rear end portion of the inclined wall portion is located at a portion of the cover wall portion adjacent to the air outlet from the rear side.

3. The device for reducing air resistance for a vehicle according to claim 2 , wherein the air outlets are opened at a plurality of positions spaced apart from one another in the orthogonal direction of the cover wall portion.

4. 4. The vehicle air resistance reduction device according to claim 3, wherein an intake port is opened in the cover wall portion forward of the air outlet port, the intake port communicating the outside of the housing with the air flow passage chamber and taking in air from outside the housing into the air flow passage chamber.

5. 5. The device for reducing air resistance for a vehicle according to claim 4, wherein the air inlet extends in a direction inclined with respect to the outer surface of the cover wall portion so as to approach the air flow passage chamber toward the rear.

6. 6. The vehicle air resistance reduction device according to claim 5, wherein an auxiliary protrusion is formed in the cover wall portion at a location adjacent to the rear of the air intake, the auxiliary protrusion protruding outwardly from the housing in the direction in which the air intake extends to assist in the intake of the air into the air flow path chamber.

7. A guide wall is disposed within the housing; 5. The vehicle air resistance reduction device as described in claim 4, wherein the guide wall portion has an inclined portion between the air inlet and the inclined wall portion, the inclined portion being inclined with respect to the fore-and-aft direction so as to move away from the cover wall portion toward the rear, thereby guiding the air taken in from the air inlet to the inclined wall portion.

8. The inlets are opened at a plurality of locations on the cover wall that are spaced apart from each other in the orthogonal direction, the housing includes air flow passage portions each having the air flow passage chamber at a plurality of locations in the perpendicular direction, Each air flow path portion includes a pair of opposing wall portions that face each other in the orthogonal direction with the air flow path chamber therebetween, A front end of each air flow passage chamber is connected to the intake port, and a rear end of each air flow passage chamber is connected to the air outlet port, 5. The device for reducing air resistance for a vehicle according to claim 4, wherein a distance between the pair of opposing walls is set to become gradually smaller from the front end portion to the rear end portion of the air flow passage chamber.

9. 5. The vehicle air resistance reduction device according to claim 4, wherein a drain hole is formed in a portion of the housing that forms a bottom of the air flow passage chamber, for connecting the outside of the housing to the air flow passage chamber.

10. a blower fan is disposed within the housing to blow air in the air flow passage chamber and to blow the air out of the air outlet, 3. The vehicle air resistance reduction device according to claim 2, wherein a portion of the housing has an intake port that connects the outside of the housing with the air flow path chamber and serves as a passageway through which air outside the housing is drawn into the air flow path chamber as the blower fan is operated.

11. The blower fan is removably disposed within the housing, The housing is removably attached to the vehicle body, the housing includes a contact wall portion that contacts the vehicle body when the housing is attached to the vehicle body, The vehicle air resistance reduction device according to claim 10, wherein the contact wall portion has an opening for allowing the blower fan to pass between the inside and the outside of the housing when the housing is detached from the vehicle body.

12. The device for reducing air resistance for a vehicle according to claim 10, wherein the inclined wall portion is provided with a drain hole for communicating the outside of the housing with the air flow passage chamber.

13. The cover wall portion is formed in a shape extending in a vehicle width direction as the orthogonal direction and constitutes an upper end portion of the housing, The device for reducing air resistance for a vehicle according to any one of claims 1 to 12, wherein the air outlet is opened in a state of extending in a vertical direction in a part of the cover wall portion in the vehicle width direction.

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