Vehicle rear body structure

Abstract

This rear vehicle body structure comprises: a rear floor pan (10) that is provided recessed downward and has a tire well portion (11) capable of storing a spare tire S in the rear; and a rear bumper (30) that is positioned to the vehicle rear of the rear floor pan (10), faces the tire well portion (11) in the vehicle front-rear direction, and has a lower end surface extending in the vehicle front-rear direction, wherein the lower surface of the tire well portion (11) has a rear inclined surface (16) inclining at an upward gradient toward the vehicle rear, and the lower end surface of the rear bumper (30) extends on an extending surface where the rear inclined surface (16) is extended to the vehicle rear. A flow of air passing below a vehicle body (1) is rectified so as to smoothly run up toward the rear along the rear inclined surface (16) and the connected rear bumper (30) from the rear inclined surface (16), which decreases air resistance and improves aerodynamic performance.

Description

[Technical Field]

[0001] The present invention relates to a rear vehicle body structure with excellent aerodynamic performance. [Background technology]

[0002] In many automobiles, a tire well portion capable of storing a spare tire is provided at the rear of the rear floor pan as part of the rear body structure. The tire well portion is a generally cylindrical recess so as to match the shape of the spare tire, and as a result, a bulging portion is formed on the underside of the vehicle body.

[0003] Conventionally, the bulging portion of the underside of the tire well has almost no slope and is nearly parallel to the road surface. In addition, there is a step or gap between the rear bumper located at the rear of the rear floor pan, and in any case, the shape is not suitable from an aerodynamic standpoint (see Figure 2 of Patent Document 1, etc.).

[0004] Therefore, even if the air flow passing over the upper side of the vehicle is not particularly problematic from an aerodynamic standpoint, the air flow passing under the vehicle is poor, resulting in a problem of increased overall air resistance. This condition is also referred to as the air not easily separating from the vehicle body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent No. 5354225 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the problem to be solved by the present invention is to improve the aerodynamic performance of a rear body structure of a vehicle. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the rear body structure of the vehicle of the present invention comprises a rear floor pan having a tire well portion at the rear that is recessed downward and can accommodate a spare tire, and a rear bumper that is located rearward of the rear floor pan, faces the tire well portion in the fore-and-aft direction of the vehicle, and has a lower end surface that extends in the fore-and-aft direction of the vehicle, wherein the lower surface of the tire well portion has a rearward inclined surface that slopes upward toward the rear of the vehicle, and the lower end surface of the rear bumper extends on an extension surface that extends the rearward inclined surface toward the rear of the vehicle.

[0008] The rear body structure of the vehicle according to the invention may further include a hook for towing the vehicle, and a reinforcement extending in the fore-and-aft direction of the vehicle along the underside of the tire well portion and to which the hook is fixed, wherein the tire well portion has a groove portion recessed upward in its underside and extending in the fore-and-aft direction of the vehicle, the reinforcement being housed within the groove portion and joined to the tire well portion, and the groove portion is formed to a depth such that the reinforcement does not protrude below the rear inclined surface.

[0009] In the rear body structure of the vehicle according to the invention, the tire well portion has a support bracket for supporting the spare tire housed on its upper surface from below, and the support bracket can be configured to be positioned so as to overlap the reinforcement in the vertical direction of the vehicle.

[0010] In the rear body structure of the vehicle according to the invention, the tire well portion has a bulge portion formed by bulging downward in the rearward portion of the vehicle on its underside, and the rear inclined surface can be configured to be formed from the lowest end portion located at the lowest position of the bulge portion toward the rear of the vehicle.

[0011] In the rear body structure of the vehicle according to the invention, the portion forward of the lowest end of the bulge portion is a forward inclined surface that slopes downward toward the rear of the vehicle, and the forward inclined surface can be configured to be a curved surface that is continuous with the rear inclined surface in a curved manner.

[0012] In the rear body structure of a vehicle according to the present invention, the rear floor pan may have a vent hole for discharging coating fluid during painting, and the vent hole may be located at the lowest end of the bulge portion. [Effects of the Invention]

[0013] Because the rear body structure of the vehicle according to the invention is configured as described above, the air flow passing under the vehicle body is rectified so that it surges rearward along the rear inclined surface and the rear bumper that is smoothly connected to this rear inclined surface, thereby reducing air resistance and improving aerodynamic performance. [Brief explanation of the drawings]

[0014] [Figure 1] (a) and (b) are cross-sectional views of the rear body structure of the embodiment, where (a) is a longitudinal cross-sectional view at a location other than the rear floor pan groove portion (cross-sectional view along line AA in Figure 2(b)), and (b) is a longitudinal cross-sectional view at the rear floor pan groove portion (cross-sectional view along line BB in Figure 2(b)). [Figure 2] 1A and 1B are perspective views of a rear vehicle body structure according to an embodiment, where FIG. 1A is a perspective view from above and FIG. 1B is a perspective view from below. [Figure 3] 5 is a cross-sectional view (cross-sectional view taken along line CC in FIG. 4) of the rear vehicle-body structure according to the embodiment. [Figure 4] FIG. 2 is a plan view of the rear vehicle-body structure of the embodiment, seen from the underside. [Figure 5] FIG. 2 is a schematic diagram showing an air flow in the rear vehicle body structure according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The rear body structure of a vehicle shown in FIGS. 1(a) to 4 includes a rear floor pan 10, a hook 20, and a rear bumper 30 located at the rear of the entire body 1 of the automobile.

[0016] As shown in the figure, the rear floor pan 10 has a tire well portion 11 at its rear that can store a spare tire S. The tire well portion 11 is located between the pair of left and right rear wheels 2 of the vehicle body 1 and extends rearward from there. In addition, a pair of side members (not shown) extending in the front-rear direction of the vehicle body 1 are arranged on the left and right sides of the rear floor pan 10.

[0017] As shown in Figures 1(a), 1(b), 2(a) and 3, the tire well portion 11 is recessed downward on the upper surface side of the rear floor pan 10, forming an approximately cylindrical recess that matches the shape of the spare tire S. As shown in Figures 1(a), 1(b), and 3, protruding support portions 12 and 13 are provided at the bottom of the upper surface of the tire well portion 11 to support the spare tire S at three points. As a result, the spare tire S is supported stably in the tire well portion 11.

[0018] As shown in Figures 1(a), 1(b) and 3, the support parts 12 are formed integrally with the rear floor pan 10 at the front side within the tire well part 11 and in a pair in the left-right direction of the vehicle body 1. On the other hand, as shown in the same figure, the support portion 13 is formed by attaching a convex support bracket 13 separate from the rear floor pan 10 to the bottom of the tire well portion 11 at the rear side within the tire well portion 11.

[0019] As shown in FIGS. 1(a) and 1(b), a tire mounting bracket 14 consisting of a shaft portion 14a and a fastener 14b is provided at the center of the upper surface of the tire well portion 11. The spare tire S can be fixed in the tire well portion 11 by passing the shaft portion 14a through the center hole of the spare tire S and fastening it with a fastener 14b. This prevents the spare tire from shifting within the tire well portion 11.

[0020] As shown in the figure, the lower surface of the tire well portion 11 at the rear side of the vehicle bulges downward to form a bulging portion 15 . A lowermost end portion 15a is located at the lowest portion of the bulging portion 15. Further, the portion of the bulging portion 15 that is further forward of the lowermost end portion 15a of the bulging portion 15 is a forward inclined surface 15b that slopes downward toward the rear of the vehicle. As shown in Figures 1(a), 1(b) and 2(b), the forward inclined surface 15b of the bulge portion 15 is curvedly continuous with the non-bulging lower surface of the tire well portion 11 in a position forward of the bulge portion 15. In this way, the boundary between the area in front of the bulge 15 of the tire well portion 11 and the bulge 15 is smoothly continuous, so that the resistance from the air passing under the vehicle body 1 at the boundary is reduced compared to when a step or the like is formed at the boundary.

[0021] 1(a), 1(b), and 2(b), the bulging portion 15 slopes upward from the lowest end 15a toward the rear of the vehicle, forming a rear inclined surface 16 that runs upward toward the rear. The front inclined surface 15b and the rear inclined surface 16 are continuous in a curved shape, forming a curved surface as a whole. By providing such a slope, the air passing under the vehicle body 1 is rectified so that it flows out diagonally upward from the rear. By forming the lower surface of the tire well portion 11 as the bulging portion 15, it becomes easy to form the front inclined surface 15b and the rear inclined surface 16 that are continuous with the rear bumper 30.

[0022] As shown in the figure, the range in which the rear inclined surface 16 is formed in the longitudinal direction of the vehicle body is from near the midpoint between the tire mounting bracket 14 and the support bracket 13 to the rear edge of the tire well portion 11 . Here, the starting point of the inclination of the rear inclined surface 16 is the lowest end 15a of the bulge portion 15, and the thickness of the wall surface of the bulge portion 15 (tire well portion 11) is at its maximum at this lowest end 15a, i.e., near the midpoint between the tire mounting bracket 14 and the support bracket 13. Furthermore, as shown in FIG. 2(b), the rear inclined surface 16 is formed over the entire area of ​​the bulging portion 15 in the left-right direction of the vehicle body. Here, it is considered that the wider the rear inclined surface 16 is in the front-rear and left-right directions, the greater the flow straightening effect. The inclination angle of the rear inclined surface 16 is not particularly limited, but can be, for example, about several degrees.

[0023] The rear floor pan 10 is painted by electrodeposition coating. As shown in Figures 2(a) and 2(b), a pair of holes 17 for draining the coating liquid during painting are provided on the left and right sides of the bottom end 15a of the bulge 15. By providing the holes 17 in such positions, the coating liquid can be smoothly discharged from the holes 17 when painting the rear floor pan 10, thereby suppressing coating defects.

[0024] 2(a) to 4, a long and narrow groove 18 extending in the front-rear direction is formed in the left-right center of the bulge 15. The groove 18, recessed upward from the lower surface of the tire well 11, cuts through the bulge 15, and its cross section perpendicular to the longitudinal direction has an inverted U-shape. The recessed grooves 18 act like ribs, thereby reinforcing the bulging portions 15 .

[0025] As shown in Figures 1(a), 1(b), 2(a), 2(b) and 4, a towing hook 20 used for transporting by ship, etc., is attached to the rear edge of the underside of the tire well portion 11 via a reinforcement 21. As shown in FIG. 3, the position of the reinforcement 21 of the hook 20 overlaps in the vertical direction of the vehicle body 1 with the mounting position of the support bracket 13 that supports the spare tire S in the tire well portion. In this way, by arranging the support bracket 13 at the same location above and below the hook 20, it is possible to suppress an increase in the height dimension in the vertical direction and suppress an increase in mass.

[0026] 1(a) and 2(b), the reinforcement 21 is elongated in the front-to-rear direction of the vehicle body, and is housed in the recessed groove portion 18 of the bulging portion 15, as shown in Fig. 3. The depth and width of the recessed groove portion 18 are adjusted so that the reinforcement 21 does not protrude, in particular so that it does not protrude below the rear inclined surface 16. In this way, when attaching a hook 20 to the vehicle body 1, if the reinforcement 21 protrudes from the underside of the tire well portion 11, the resistance from the air passing under the vehicle body 1 will be large, but by storing the reinforcement 21 in the recessed groove portion 18 and configuring it so that it does not protrude from the underside of the tire well portion 11, the air resistance can be reduced.

[0027] As shown in Figures 1(a), 1(b) and 4, a cross member 19 extending in the left-right direction of the vehicle body 1 is arranged on the underside of the rear floor pan 10, forward of the tire well portion 11, and the front end of the reinforcement 21 is attached to this cross member 19. The cross member 19 is disposed between the pair of left and right side members described above, and a rear suspension (not shown) attached to the rear wheel 2 is supported by this cross member 19. As shown in the figure, the hook 20 (the tip portion thereof) is located at the rear end of the reinforcement 21.

[0028] As shown in Figures 1(a) and 1(b), a rear bumper (rear bumper fascia) 30 is attached to the lower rear end of the vehicle body 1 via a bumper beam 31. This bumper beam 31 is equipped with a crash box (not shown) that can absorb impacts. The tire well portion 11 and the rear bumper 30 face each other in the front-rear direction of the vehicle. As shown in the figure, the lower end surface of the rear bumper 30 is slightly inclined and extends in the longitudinal direction of the vehicle. The lower end surface of the rear bumper 30 is on an extension of the rearwardly extending rearward of the vehicle of the rearwardly inclined surface 16 of the bulging portion 15. As a result, the rearwardly inclined surface 16 and the lower end surface of the rear bumper 30 are flush with each other, i.e., are substantially on the same plane. Note that the term "substantially on the same plane" as used herein does not only refer to a completely on the same plane, but also includes a case where there is a minute gap or the like that does not make a significant difference in terms of aerodynamics.

[0029] As shown in FIG. 5, the air that passes under the vehicle body 1 and is straightened by the rear inclined surface 16 so that it rushes diagonally upward from the rear is sent out smoothly without generating resistance because there is no step or the like between the rear inclined surface 16 and the rear bumper 30. As shown in the figure, this, combined with the air flow passing over the vehicle body 1 and flowing diagonally downward from the rear, makes it easier for air to separate from the vehicle body, and the rear body structure of the embodiment improves the aerodynamic performance of the vehicle.

[0030] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and all modifications and variations within that scope and in a meaning equivalent to the claims are intended to be included.

[0031] For example, an attempt can be made to further improve aerodynamic performance by positioning the torsion beam of the rear suspension on an extension of the rear inclined surface 16 toward the front of the vehicle body 1, and arranging the torsion beam, rear inclined surface 16, and rear bumper 30 in a straight line.

[0032] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0033] This application is based on a Japanese patent application (Patent Application No. 2022-048293) filed on March 24, 2022, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0034] 1. Body 2 rear wheels 10 Rear floor pan 11 Tire well 12 Support part 13 Support bracket (support part) 14 Tire mounting bracket 14a Shaft 14b Fastener 15 Bulge 15a Bottom end 15b Front slope 16 Rear slope 17 Perforation 18 Groove 19 Cross member 20 Hook 21 Reinforce 30 Rear bumper 31 Bumper beam S spare tire

Claims

1. a rear floor pan having a tire well portion recessed downward and capable of accommodating a spare tire; a rear bumper located rearward of the rear floor pan, facing the tire well portion in the vehicle longitudinal direction, and having a lower end surface extending in the vehicle longitudinal direction; A rearward inclined surface that slopes upward toward the rear of the vehicle is formed on the lower surface of the tire well portion over the entire area of ​​the lower surface of the tire well portion in the left-right direction of the vehicle body, a lower end surface of the rear bumper extends on an extension plane of the rear inclined surface extending rearward of the vehicle; a hook for towing the vehicle; a reinforcement extending in the vehicle front-rear direction along the lower surface of the tire well portion and to which the hook is fixed; Furthermore, The tire well portion has a groove portion recessed upward in a lower surface thereof and extending in the vehicle front-rear direction, The reinforcement is housed in the groove portion and joined to the tire well portion, The recessed groove portion is formed to a depth that prevents the reinforcement from protruding downward from the rear inclined surface.

2. The tire well portion is a support bracket provided at the bottom of the upper surface thereof for supporting the stored spare tire from below; The rear body structure of a vehicle according to claim 1 , wherein the support bracket is provided at a position where it overlaps with the reinforcement in the vertical direction of the vehicle.

3. The tire well portion is a bulging portion formed by bulging downward at a portion of the lower surface thereof toward the rear of the vehicle, 3. The rear body structure for a vehicle according to claim 1, wherein the rearwardly inclined surface is formed from a lowermost end portion of the bulging portion that is located at the lowest position toward the rear of the vehicle.

4. a portion of the bulging portion forward of the lowermost end portion thereof is a forward inclined surface that slopes downward toward the rear of the vehicle, 4. The rear body structure of a vehicle according to claim 3, wherein the front inclined surface is formed as a curved surface that is continuous with the rear inclined surface.

5. the rear floor pan has a hole for discharging coating fluid during painting, 4. The rear body structure of a vehicle according to claim 3, wherein the hole is located at the lowermost end of the bulging portion.

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