Vehicular imaging device

Abstract

Vehicular imaging devices 10A to 10C each comprise an imaging unit 18 that includes a lens 19 for imaging a side part rearward of a vehicle 1, and a housing 12 that accommodates the imaging unit 18 so that the lens 19 is exposed to the outside, the housing being attached to the vehicle 1. When viewed from the vehicle height direction, an outer peripheral part of the housing 12 includes an inner side part 12a that is disposed so as to be in contact with the vehicle 1 and extends in the vehicle length direction, and a rear side part 12e that is continuous with the rear side of the inner side part 12a in the vehicle length direction and extends outward in the vehicle width direction. An inclined part 12g that is inclined rearward in the vehicle length direction from the outside to the inside in the vehicle width direction, is formed in at least a portion of the rear side part 12e.

Description

Vehicle imaging device

[0001] The present invention relates to an imaging device for a vehicle.

[0002] Patent Document 1 discloses a vehicle imaging device that houses an imaging unit (camera) that captures images of the side rear of the vehicle within a housing. The outer periphery of the housing includes an inner portion, an outer portion, a front portion, and a rear portion. The inner portion is disposed so as to contact the vehicle door panel and extends in the vehicle length direction. The outer portion is positioned outwardly in the vehicle width direction relative to the inner portion and extends in the vehicle length direction. The front portion is inclined from the inner side to the outer side in the vehicle width direction, from the front end of the inner portion to the front end of the outer portion, toward the rear in the vehicle length direction. The rear portion extends in the vehicle width direction from the rear end of the inner portion to the rear end of the outer portion, perpendicular to the door panel.

[0003] JP 2020-32822 A

[0004] In the vehicle imaging device of Patent Document 1, air flows from the front to the rear of the vehicle along the outer surface of the housing when the vehicle is traveling. At the rear of the rear section, air is drawn inward in the vehicle width direction from the rear end of the outer section in the vehicle length direction, which can create a wake accompanied by a reverse flow or a vortex. The generation of a wake increases air resistance, resulting in a decrease in the vehicle's fuel efficiency.

[0005] An object of the present invention is to reduce air resistance by suppressing the generation of a wake behind the housing, thereby suppressing a decrease in fuel efficiency of the vehicle.

[0006] The present invention provides an imaging device for a vehicle that includes an imaging unit including a lens that images the rear side of the vehicle, and a housing that houses the imaging unit so that the lens is exposed to the outside and is attached to the vehicle, wherein, when viewed from the vehicle height direction, the outer periphery of the housing includes an inner portion that is arranged to be in contact with the vehicle and extends in the vehicle length direction, and a rear side portion that is connected to the rear side of the inner portion in the vehicle length direction and extends outward in the vehicle width direction, and at least a part of the inner side in the vehicle width direction is formed with an inclined portion that is inclined from the outside in the vehicle width direction to the inside and rearward in the vehicle length direction.

[0007] At least a portion of the inner side of the rear side of the housing in the vehicle width direction is formed with an inclined portion that slopes from the outer side in the vehicle width direction to the inner side toward the rear in the vehicle length direction. Therefore, when the vehicle is traveling, at the rear side of the rear side, air that is drawn in from the rear end of the outer side portion toward the inner side in the vehicle width direction is guided rearward in the vehicle length direction along the slope of the inclined portion before it becomes a wake that involves a reverse flow or a vortex. This makes it possible to suppress the generation of a wake behind the rear side, thereby reducing air resistance on the housing and suppressing a decrease in the vehicle's fuel efficiency.

[0008] In the present invention, the generation of a wake behind the housing is suppressed, thereby reducing air resistance and suppressing a decrease in the fuel efficiency of the vehicle.

[0009] 1 is a perspective view of a vehicle imaging device according to a first embodiment of the present invention attached to a vehicle door; FIG. 2 is a perspective view of the vehicle imaging device removed from the vehicle door; FIG. 3 is a plan view of the vehicle imaging device of FIG. 1; FIG. 4 is a side view of the vehicle imaging device of FIG. 1; FIG. 5 is a side view of the vehicle imaging device of a second embodiment; FIG. 6 is a plan view of a vehicle imaging device of a third embodiment; FIG. 7 is a diagram showing the air flow around the housing of a conventional vehicle imaging device as viewed from the vehicle height direction; FIG. 8 is a diagram showing the air flow around the housing of the vehicle imaging device of the first embodiment as viewed from the vehicle height direction; FIG. 9 is a graph showing the relationship between the housing shape and the air drag coefficient Cd value for the conventional example, the first comparative example, and the third embodiment; and FIG. 10 is a graph showing the relationship between the thickness of the inclined portion of the housing and the air drag coefficient Cd value. FIG. 11 is a diagram showing the air flow around the housing of the vehicle imaging device of the first embodiment as viewed from the vehicle width direction; FIG. 12 is a diagram showing the air flow around the housing of the vehicle imaging device of the second embodiment as viewed from the vehicle width direction; and FIG. 13 is a diagram showing the air flow around the housing of the vehicle imaging device of the second comparative example as viewed from the vehicle width direction.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] First Embodiment Referring to Fig. 1, a vehicle imaging device 10A according to a first embodiment of the present invention is attached to an outer panel (vehicle body panel) 2 of a vehicle side door 1, and captures images of the rear side of the vehicle. The vehicle imaging device 10A shown in Fig. 1 is for the left side door 1. The vehicle imaging device for the right side door has a shape symmetrical to the vehicle imaging device 10A for the left side door 1.

[0012] In the accompanying drawings, the X direction is the vehicle length direction, with the arrow pointing in the direction of the front side and the opposite direction of the arrow pointing in the direction of the rear side. The Y direction is the vehicle width direction, with the arrow pointing inward (inside the vehicle) and the opposite direction of the arrow pointing outward (outside the vehicle). The Z direction is the vehicle height direction, with the arrow pointing in the direction of the top side and the opposite direction of the arrow pointing in the direction of the bottom side.

[0013] 1 to 3, the vehicle imaging device 10A includes a housing 12, a bracket (mounting member) 16, and a camera (imaging unit) 18. In this embodiment, the shape of the housing 12 is improved to improve the aerodynamic characteristics of the housing 12.

[0014] First, an overview of the vehicle imaging device 10A will be described.

[0015] 1 and 4, the housing 12 is composed of an upper housing 14 and a lower housing 13 that are divided into upper and lower halves. A storage section that is a space for storing a bracket 16 and a camera 18 is formed inside the housing 12. The housing 12 is attached to the side door 1 via the bracket 16 and protrudes outward in the vehicle width direction along the XY plane. The housing 12 may be inclined with respect to the vehicle height direction.

[0016] The lower housing 13 includes a lower wall 13a extending along the XY plane and a peripheral wall 13b connected to the outer periphery of the lower wall 13a except for the inner portion thereof in the vehicle width direction that contacts the outer panel 2. The upper housing 14 includes an upper wall 14a located above the lower wall 13a at a distance and extending along the XY plane, and a peripheral wall 14b connected to the outer periphery of the upper wall 14a except for the inner portion thereof in the vehicle width direction that contacts the outer panel 2. The peripheral wall 13b protrudes upward in an arc shape from the outer periphery of the lower wall 13a. The peripheral wall 14b protrudes downward in an arc shape from the outer periphery of the upper wall 14a. The peripheral walls 13b, 14b are provided with an assembly structure (not shown) using engaging claws or the like for assembling the lower housing 13 and the upper housing 14 together. The peripheral walls 13b, 14b may be assembled by welding.

[0017] A generally U-shaped notch 13c is formed in a corner of the peripheral wall 13b of the lower housing 13 that is located on the outer side in the vehicle width direction and on the rear side in the vehicle length direction. A protrusion 14c having a shape complementary to the notch 13c is provided in the peripheral wall 14b of the upper housing 14 at a position corresponding to the notch 13c of the lower housing 13. A recess 14d recessed toward the front side in the vehicle length direction is provided in the protrusion 14c, and an exposure hole 14e is provided at the bottom of the recess 14d to expose the lens 19 of the camera 18 to the outside.

[0018] 2 , the bracket 16 is made of a metal (e.g., aluminum) with good thermal conductivity. The bracket 16 has an inner plate portion 16a exposed to the outside from an opening located at the inner end (inner portion 12a, which will be described in detail later) of the housing 12 in the vehicle width direction. The rest of the bracket 16 except for the inner plate portion 16a is housed within the housing 12.

[0019] The inner plate portion 16a is disposed so as to be in surface contact with the metal outer panel 2. The inner plate portion 16a is provided with a mounting portion 16b that protrudes inward in the vehicle width direction for mounting to the outer panel 2. The entire vehicle imaging device 10A including the bracket 16 is attached to the side door 1 by bolting to the mounting portion 16b.

[0020] 1 and 3, the camera 18 is disposed on a bracket 16 (see FIG. 2) and is housed together with the bracket 16 in the housing 12. The camera 18 is disposed on the front side of the protrusion 14c in the vehicle length direction in the housing 12, and includes a lens 19 exposed to the outside through the exposure hole 14e. The optical axis Ao of the camera 18 is inclined outward in the vehicle width direction from the front side to the rear side in the vehicle length direction. Image data captured by the camera 18 through the lens 19 is sent to an ECU (Electronic Control Unit) (not shown) of the vehicle and displayed on an in-vehicle monitor (not shown).

[0021] Next, the shape of the housing 12 will be specifically described.

[0022] 1, 3, and 4, the inner portions of the lower housing 13 and the upper housing 14 in the vehicle width direction constitute an inner portion 12a of the outer periphery of the housing 12. The peripheral wall 13b of the lower housing 13 and the peripheral wall 14b of the upper housing 14 constitute a front portion 12b, an outer portion 12d, and a rear portion 12e of the outer periphery of the housing 12.

[0023] The inner portion 12a is disposed in contact with the outer panel 2 and extends in the vehicle length direction along the outer panel 2. An opening is formed in the inner portion 12a that communicates with the internal space of the housing 12. The opening is defined by the lower wall 13a, the upper wall 14a, and the peripheral walls 13b, 14b, and is closed by an inner plate portion 16a of the bracket 16.

[0024] The front portion 12b has a semicircular cross-sectional shape that protrudes generally forward in the vehicle length direction and extends outward in the vehicle width direction from the front end of the inner portion 12a in the vehicle length direction. More specifically, the front portion 12b is inclined from the inner side to the outer side in the vehicle width direction toward the rear in the vehicle length direction. If the inclination angle θ1 of the front portion 12b relative to the inner portion 12a is excessively large, air resistance will increase when the vehicle is traveling. To prevent such problems, the inclination angle θ1 is preferably set to a range of 50 degrees or less, and is set to 50 degrees in this embodiment.

[0025] The outer portion 12d is positioned outward in the vehicle width direction relative to the inner portion 12a and spaced apart from the inner portion 12a. The outer portion 12d has a semicircular arc cross section that protrudes outward in the vehicle width direction, connects to the outer end of the front portion 12b in the vehicle width direction, and extends rearward in the vehicle length direction. The overall length of the outer portion 12d in the vehicle length direction is shorter than the overall length of the inner portion 12a in the vehicle length direction, and is set as short as possible within a range that allows for installation space for the camera 18.

[0026] The rear portion 12e is connected to the rear end of the inner portion 12a in the vehicle length direction and the rear end of the outer portion 12d in the vehicle length direction, and extends in the vehicle width direction. A recess 14d including an exposure hole 14e that exposes the lens 19 of the camera 18 is formed at the outer end of the rear portion 12e in the vehicle width direction. In this embodiment, the rear portion 12e includes a non-inclined portion 12f located on the outer side in the vehicle width direction and an inclined portion 12g located on the inner side in the vehicle width direction. The rear portion 12e also includes a continuous portion 12h between the non-inclined portion 12f and the inclined portion 12g.

[0027] The non-inclined portion 12f has a semicircular cross-section that protrudes rearward in the vehicle length direction and is continuous with the rear end of the outer portion 12d in the vehicle length direction. The outer end of the non-inclined portion 12f in the vehicle width direction is chamfered by forming the recess 14d, and is inclined from the outer side in the vehicle width direction to the inner side in the vehicle length direction rearward. The inclination angle of the portion where the recess 14d is formed relative to the inner portion 12a is greater than the inclination angle θ2 of the inclined portion 12g (described in detail below) and smaller than the inclination angle θ3 of the perpendicular line Lp. The portion of the non-inclined portion 12f other than the region where the recess 14d is formed extends linearly inward in the vehicle width direction so as to be approximately perpendicular to the inner portion 12a when viewed from the vehicle height direction. The non-inclined portion 12f may be curved when viewed from the vehicle height direction, and the shape of the non-inclined portion 12f can be changed as needed as long as it does not increase air resistance to the housing 12.

[0028] The inclined portion 12g is configured to guide air entrained behind the rear portion 12e toward the rear side in the vehicle length direction during vehicle travel, thereby suppressing the generation of reverse flow or a wake accompanied by a vortex behind the rear portion 12e, thereby reducing air resistance to the housing 12. The inclined portion 12g has a generally semicircular arc cross section that protrudes outward in the vehicle width direction, and is connected to the rear end of the inner portion 12a in the vehicle length direction and to the inner end of the non-inclined portion 12f in the vehicle width direction via a continuous portion 12h. When viewed from the vehicle height direction, the inclined portion 12g extends linearly, inclining from the outer side to the inner side in the vehicle width direction toward the rear side in the vehicle height direction with respect to the inner portion 12a. The inclined portion 12g may be curved when viewed from the vehicle height direction, and the shape of the inclined portion 12g can be changed as needed as long as it does not increase air resistance to the housing 12.

[0029] The continuous portion 12h is connected to the inner end of the non-inclined portion 12f and the outer end of the inclined portion 12g in the vehicle width direction so as to be in contact with the non-inclined portion 12f and the inclined portion 12g, respectively. The cross-sectional shape of the continuous portion 12h is a semicircular arc that protrudes obliquely outward in the vehicle width direction and toward the rearward in the vehicle length direction. When viewed from the vehicle height direction, the continuous portion 12h is an arc that protrudes obliquely forward in the vehicle length direction and toward the inner in the vehicle width direction, and is formed with a radius of curvature (e.g., 21.5 mm) that does not interfere with the flow of air from the non-inclined portion 12f to the inclined portion 12g.

[0030] Next, the configuration of the inclined portion 12g will be described in more detail.

[0031] Referring to FIG. 3 , the inclined portion 12g is inclined at an inclination angle θ2 with respect to the inner portion 12a. If the inclination angle θ2 is excessively large, a wake may be generated behind the rear portion 12e, increasing air resistance to the housing 12. If the inclination angle θ2 is excessively small, the overall length of the inclined portion 12g in the vehicle length direction increases, increasing the dimension of the housing 12 in the vehicle length direction. To prevent these inconveniences, the inclination angle θ2 of the inclined portion 12g is set smaller than the inclination angle θ3 (e.g., 70 degrees) of the perpendicular line Lp intersecting the optical axis Ao of the camera 18 with respect to the inner portion 12a. More specifically, the inclination angle θ2 is preferably set in the range of 25 degrees to 54 degrees, inclusive, and is set to 30 degrees in this embodiment.

[0032] 4, the inclined portion 12g is formed with a thickness T2 equivalent to the thickness T1 (e.g., 30 mm) of the inner portion 12a, which corresponds to the maximum thickness of the housing 12 in the vehicle height direction. If the thickness T2 of the inclined portion 12g is made excessively thin, the ability to guide air rearward in the vehicle length direction decreases, and a wake may be generated behind the rear portion 12e. In other words, the air resistance to the housing 12 varies depending on the thickness T2 of the inclined portion 12g, and decreases as the inclined portion 12g becomes thicker. Therefore, the thickness T2 of the inclined portion 12g is preferably set to 60% or more of the thickness T1 of the inner portion 12a, and is set to 100% in this embodiment.

[0033] 3, the inclined portion 12g is formed to have a lateral width W2 relative to the overall width W1 of the rear side portion 12e in the vehicle width direction, which corresponds to the distance from the inner portion 12a to the outer portion 12d. If the lateral width W2 of the inclined portion 12g is excessively wide, the overall length of the inclined portion 12g in the vehicle length direction will be long, and the dimension of the housing 12 in the vehicle length direction will be large. If the lateral width W2 of the inclined portion 12g is excessively narrow, a wake will be generated behind the rear side portion 12e, which may increase air resistance to the housing 12. To prevent these inconveniences, the proportion of the lateral width W2 of the inclined portion 12g to the overall width W1 of the rear side portion 12e is preferably set to a range of 30% to 50% and is set to 40% in this embodiment.

[0034] The continuous portion 12h of the rear side portion 12e has its inner end in the vehicle width direction located rearward of its outer end in the vehicle length direction, and is generally inclined from the outer side to the inner side in the vehicle width direction toward the rear in the vehicle length direction. Therefore, the continuous portion 12h can also be considered part of the inclined portion 12g. The inclined portion 12g, including the continuous portion 12h, is formed to have a width W3. The ratio of the width W3 of the inclined portion 12g, including the continuous portion 12h, to the overall width W1 of the rear side portion 12e is preferably set in the range of 45% to 65% and in the present embodiment, set to 55%. In other words, the ratio of the width W1-W3 of the non-inclined portion 12f to the overall width W1 of the rear side portion 12e is preferably set in the range of 35% to 55% and in the present embodiment, set to 45%.

[0035] In the vehicle imaging device 10A configured as described above, air flows from the front to the rear of the vehicle along the outer surface of the housing when the vehicle is traveling (see FIGS. 8 and 11).

[0036] 8, as viewed from the vehicle height direction, when air approaches the housing 12 from the front side in the vehicle length direction, it flows from the inside to the outside in the vehicle width direction along the inclination of the front side portion 12b, and after passing the outer end of the front side portion 12b in the vehicle width direction, it flows rearward in the vehicle length direction along the outer side portion 12d. After passing the rear end of the outer side portion 12d in the vehicle length direction, most of the air continues to flow rearward in the vehicle length direction. Meanwhile, some of the air is drawn inward in the vehicle width direction and flows inward in the vehicle width direction along the non-inclined portion 12f of the rear side portion 12e, and then is guided rearward in the vehicle length direction along the inclined portion 12g.

[0037] 11, when viewed from the outside in the vehicle width direction, as the air approaches the housing 12 from the front side in the vehicle length direction, it splits into upper and lower flows along the curved shape of the front side portion 12b and flows rearward in the vehicle length direction along the lower wall 13a and the upper wall 14a. After that, when the air passes over the rear side portion 12e, which is the rear end in the vehicle length direction of the lower wall 13a and the upper wall 14a, the split air flows together and flows rearward in the vehicle length direction.

[0038] In this way, no reverse flow or wake accompanied by a vortex occurs in any region of the rear side portion 12e of the housing 12 in the vehicle width direction, so that air resistance to the housing 12 can be reduced.

[0039] The vehicle imaging device 10A of this embodiment has the following features.

[0040] The rear side portion 12e of the housing 12 is formed with an inclined portion 12g that is inclined from the outer side in the vehicle width direction to the inner side toward the rear side in the vehicle length direction. Therefore, when the vehicle is traveling, behind the rear side of the rear side portion 12e, air that is drawn in from the rear end of the outer portion 12d toward the inner side in the vehicle width direction is guided toward the rear side in the vehicle length direction along the inclination of the inclined portion 12g before it becomes a wake that involves a reverse flow or a vortex. This makes it possible to suppress the generation of a wake behind the rear side portion 12e, thereby reducing air resistance against the housing 12 and suppressing a decrease in the fuel efficiency of the vehicle.

[0041] When viewed from the vehicle height direction, the inclination angle θ2 of the inclined portion 12g of the housing 12 with respect to the inner portion 12a is smaller than the inclination angle θ3 of the perpendicular line Lp, which intersects with the optical axis Ao of the camera 18, with respect to the inner portion 12a. This allows the air that is drawn in from the rear end of the outer portion 12d of the housing 12 toward the inside in the vehicle width direction to be efficiently guided toward the rear in the vehicle length direction along the inclination of the inclined portion 12g. As a result, the generation of a wake behind the rear side portion 12e can be effectively suppressed, and air resistance can be efficiently reduced.

[0042] The thickness T2 of the inclined portion 12g in the vehicle height direction is set to be 60% or more of the thickness T1 of the inner portion 12a in the vehicle height direction. This allows the inclined portion 12g to efficiently guide air rearward in the vehicle length direction, thereby suppressing the generation of a wake behind the rear portion 12e and reliably reducing air resistance to the housing 12.

[0043] Other embodiments and various modifications of the present invention will be described below, but in these descriptions, points that are not particularly mentioned are the same as those in the first embodiment. In the drawings referred to below, the same elements as those in the first embodiment are denoted by the same reference numerals.

[0044] (Second embodiment) Referring to FIG. 5, a vehicle imaging device 10B of the second embodiment differs from the vehicle imaging device 10A of the first embodiment in that an inclined portion 12g including a continuous portion 12h of a rear side portion 12e of a housing 12 is formed with a thickness T2 (e.g., 20 mm) that is 60% or more and less than 100% of a thickness T1 (e.g., 30 mm) of an inner portion 12a.

[0045] The center of the thickness direction (vehicle height direction) of the inclined portion 12g including the continuous portion 12h is approximately aligned with the center of the thickness direction of the inner portion 12a, so that the distance from the upper surface of the inclined portion 12g to the upper surface of the housing 12 is equal to the distance from the lower surface of the inclined portion 12g to the lower surface of the housing 12.

[0046] (Third embodiment) Referring to Figure 6, a vehicle imaging device 10C of the third embodiment differs from the vehicle imaging device 10A of the first embodiment in that a non-inclined portion 12i is provided at the rear end of the inclined portion 12g of the rear side portion 12e of the housing 12 in the vehicle length direction, the non-inclined portion 12i being continuous with the rear end of the inner portion 12a in the vehicle length direction.

[0047] The non-inclined portion 12i has a semicircular cross-section that protrudes rearward in the vehicle length direction, and is continuous with the rear end of the inner portion 12a in the vehicle length direction and the rear end of the inclined portion 12g in the vehicle length direction. The non-inclined portion 12i extends linearly from the inclined portion 12g toward the inside in the vehicle width direction so as to be substantially perpendicular to the inner portion 12a. The width of the non-inclined portion 12i in the vehicle width direction is set to be equal to the width (W1-W3) of the non-inclined portion 12f on the outside in the vehicle width direction. The non-inclined portion 12i may be curved when viewed from the vehicle height direction, and the shape of the non-inclined portion 12i can be changed as needed as long as it does not increase air resistance to the housing 12.

[0048] In the vehicle imaging devices 10B and 10C of the second and third embodiments configured as described above, similar to the vehicle imaging device 10A of the first embodiment, air resistance can be reduced by suppressing the generation of a wake behind the housing 12, thereby suppressing a decrease in the fuel efficiency of the vehicle.

[0049] Air flow analysis was performed using the vehicle imaging devices 10A to 10C of the first to third embodiments, the conventional vehicle imaging device 10D, the vehicle imaging device 10E of the first comparative example, and the vehicle imaging device 10F of the second comparative example.

[0050] Fig. 7 shows the air flow when a conventional vehicle imaging device 10D is viewed from the vehicle height direction, and Fig. 8 shows the air flow when the vehicle imaging device 10A of the first embodiment is viewed from the vehicle height direction. The conventional vehicle imaging device 10D shown in Fig. 7 differs from the vehicle imaging device 10A of the first embodiment shown in Fig. 8 in that it does not have the inclined portion 12g including the continuous portion 12h shown in Fig. 8.

[0051] 7 , in the conventional vehicle imaging device 10D, when viewed from the vehicle height direction, air approaches the housing 12 from the front side in the vehicle length direction, flows from the inside to the outside in the vehicle width direction along the slope of the front side portion 12b. After passing the outer end of the front side portion 12b in the vehicle width direction, it flows rearward in the vehicle length direction along the outer side portion 12d. After passing the rear end of the outer side portion 12d in the vehicle length direction, most of the air continues to flow rearward in the vehicle length direction, while a portion of the air is drawn inward in the vehicle width direction and flows inward in the vehicle width direction along the rear side portion 12e. In the portion of the rear side portion 12e located in the center in the vehicle width direction, the air drawn in behind the rear side portion 12e forms a wake accompanied by a reverse flow and a vortex. As a result, a pressure difference occurs between the front portion (high-pressure region) and the rear portion (low-pressure region) of the housing 12, increasing air resistance.

[0052] 8 , in the vehicle imaging device 10A of the first embodiment, air flows in the same manner as in the conventional vehicle imaging device 10D as viewed from the vehicle height direction until it reaches the rear end of the outer portion 12d in the vehicle length direction. After passing the rear end of the outer portion 12d in the vehicle length direction, most of the air flows directly rearward in the vehicle length direction, while a portion of the air is drawn inward in the vehicle width direction and flows inward in the vehicle width direction along the non-inclined portion 12f of the rear side portion 12e. However, in the vehicle imaging device 10A of the first embodiment, an inclined portion 12g is provided on the rear side portion 12e from the vehicle width central portion to the inside via a continuous portion 12h. Therefore, the air drawn in behind the rear side portion 12e is guided rearward in the vehicle length direction along the inclined portion 12g before forming a wake accompanied by a reverse flow or vortex. As described above, it can be seen that the vehicle imaging device 10A of the first embodiment has improved aerodynamic characteristics compared to the conventional vehicle imaging device 10D, and reduces air resistance by suppressing the generation of wake behind the housing 12, thereby suppressing a decrease in the vehicle's fuel efficiency.

[0053] 9 is a graph showing the results of measuring the air drag coefficient Cd values ​​of the conventional vehicle imaging device 10D, the vehicle imaging device 10C of the third embodiment, and the vehicle imaging device 10E of the first comparative example. The vehicle imaging device 10E of the first comparative example has a parallel portion extending in the vehicle length direction instead of the inclined portion 12g in the vehicle imaging device 10C of the third embodiment shown in FIG.

[0054] 9 , the drag coefficient Cd value of the conventional vehicle imaging device 10D, in which the rear side portion 12e does not have a portion protruding rearward in the vehicle length direction, is 0.161. In contrast, the drag coefficient Cd value of the vehicle imaging device 10C of the third embodiment, in which the rear side portion 12e is configured with the non-inclined portion 12f, the continuous portion 12h, the inclined portion 12g, and the non-inclined portion 12i, is 0.158, which is smaller than the drag coefficient Cd value of the conventional vehicle imaging device 10D. On the other hand, the drag coefficient Cd value of the vehicle imaging device 10E of the first comparative example, in which a parallel portion is provided instead of the inclined portion 12g, is 0.214, which is larger than the drag coefficient Cd value of the conventional vehicle imaging device 10D. As a result, it is found that the vehicle imaging device 10C of the third embodiment, which is provided with the inclined portion 12g, can improve aerodynamic characteristics compared to the conventional vehicle imaging device 10D, and can reduce air resistance and suppress deterioration of the fuel efficiency of the vehicle by suppressing the generation of a wake behind the housing 12. On the other hand, it is found that the aerodynamic characteristics are not improved simply by providing a portion that protrudes rearward in the vehicle length direction from the rear side portion 12e, but that the inclined portion 12g is also required.

[0055] 10 is a graph showing the results of measuring the air drag coefficient Cd values ​​of vehicle imaging devices 10A, 10B, and 10F having housings 12 with different thicknesses T2 of inclined portion 12g including continuous portion 12h. Vehicle imaging device 10F of the second comparative example differs from vehicle imaging device 10A of the first embodiment in that thickness T2 of inclined portion 12g including continuous portion 12h of housing 12 is 10 mm, which is less than 60% of thickness T1 (30 mm) of inner portion 12a.

[0056] 10 , the vehicle imaging device 10A of the first embodiment, in which the ratio of the thickness T2 of the inclined portion 12g to the thickness T1 (30 mm) of the inner portion 12a is 100% (30 mm), has an air drag coefficient Cd value of 0.148, which is smaller than the air drag coefficient Cd value (0.161) of the conventional vehicle imaging device 10D. The vehicle imaging device 10B of the second embodiment, in which the ratio of the thickness T2 of the inclined portion 12g to the thickness T1 (30 mm) of the inner portion 12a is 67% (20 mm), has an air drag coefficient Cd value of 0.158, which is smaller than the air drag coefficient Cd value of the conventional vehicle imaging device 10D. The vehicle imaging device 10F of the second comparative example, in which the ratio of the thickness T2 of the inclined portion 12g to the thickness T1 (30 mm) of the inner portion 12a is 33% (10 mm), has an aerodynamic coefficient Cd value of 0.198, which is larger than the aerodynamic coefficient Cd value of the conventional vehicle imaging device 10D. These results show that the vehicle imaging devices 10A and 10B of the first and second embodiments can improve aerodynamic characteristics compared to the conventional vehicle imaging device 10D. On the other hand, it is also clear that if the thickness T2 of the inclined portion 12g is made excessively thin, as in the vehicle imaging device 10F of the second comparative example, the aerodynamic characteristics will deteriorate.

[0057] 11 and 12, in the vehicle imaging devices 10A and 10B of the first and second embodiments, no backflow or vortex-inducing wake occurs when air passes over the non-inclined portion 12f of the rear side portion 12e. On the other hand, in the vehicle imaging device 10F of the second comparative example, when air passes over the non-inclined portion 12f of the rear side portion 12e, the air above is drawn downward, and the air below is drawn upward, resulting in a backflow or vortex-inducing wake. This demonstrates that the aerodynamic characteristics of the housing 12 are not improved simply by providing the inclined portion 12g on the rear side portion 12e; the ratio of the thickness T2 of the inclined portion 12g to the thickness T1 of the inner portion 12a is also important. Furthermore, in FIG. 10, it is clear that the thickness T2 of the inclined portion 12g relative to the thickness T1 (30 mm) of the inner portion 12a needs to be at least 60% (18 mm).

[0058] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

[0059] For example, the rear side portion 12e may be formed by the non-inclined portion 12f and the inclined portion 12g without including the continuous portion 12h. Alternatively, the entire rear side portion 12e of the housing 12 may be formed by an inclined portion that inclines from the outer side to the inner side in the vehicle width direction toward the rear in the vehicle length direction.

[0060] The inclination angle θ2 of the inclined portion 12g of the rear side portion 12e of the housing 12 may be greater than or equal to the inclination angle θ3 relative to the inner portion 12a of the perpendicular line Lp intersecting the optical axis Ao of the camera 18, as long as it can reduce air resistance to the housing 12.

[0061] The thickness T2 of the inclined portion 12g of the rear side portion 12e of the housing 12 may be less than 60% as long as it is possible to suppress the generation of wakes and reduce air resistance.

[0062] 1 Side door (vehicle) 10A to 10C Vehicle imaging device 12 Housing 12a Inner portion 12e Rear portion 12g Inclined portion 18 Camera (imaging unit) 19 Lens Ao Optical axis Lp Perpendicular line intersecting the optical axis θ2 Inclination angle of inclined portion relative to the inner portion θ3 Inclination angle of perpendicular line intersecting the optical axis relative to the inner portion T1 Thickness of inner portion in vehicle height direction T2 Thickness of inclined portion in vehicle height direction

Claims

1. A vehicle imaging device comprising: an imaging unit including a lens that images the rear side of a vehicle; and a housing that houses the imaging unit so that the lens is exposed to the outside and is attached to the vehicle, wherein, when viewed from the vehicle height direction, the outer periphery of the housing includes an inner part that is arranged to be in contact with the vehicle and extends in the vehicle length direction, and a rear side part that is connected to the rear side of the inner part in the vehicle length direction and extends outward in the vehicle width direction, and at least a part of the inner side in the vehicle width direction is formed with an inclined part that is inclined from the outer side in the vehicle width direction to the inside toward the rear side in the vehicle length direction.

2. The vehicle imaging device according to claim 1, wherein the optical axis of the imaging unit is inclined outward in the vehicle width direction from the front to the rear in the vehicle length direction, and the inclination angle of the inclined portion relative to the inner portion when viewed from the vehicle height direction is smaller than the inclination angle of a perpendicular line intersecting the optical axis relative to the inner portion.

3. The vehicle imaging device according to claim 1 or 2, wherein the thickness of the inclined portion in the vehicle height direction is set to 60% or more of the thickness of the inner portion in the vehicle height direction.

Images