Heat-dissipating structure of on-board camera

Abstract

A camera casing (16) of an on-board camera (15) is fixed to the cabin interior (E) side of a front window (13) and houses a CCD camera (17) and a camera controller (18) for image processing, and a slit (16a) and a connection port (16b) are formed on the rear side. An intake port (10f) and a connection port (16b) of a rear cooler unit (9) disposed between a roof (2) and a head lining (3) are connected via a duct (21), negative pressure generated in the intake port (10f) along with the operation of the rear cooler unit (9) is caused to act in the camera casing (16) via the duct (21), and the cabin interior air is introduced into the camera casing (16) via the slit (16a).

Description

Heat dissipation structure for in-vehicle cameras

[0001] The present invention relates to a heat dissipation structure for an in-vehicle camera.

[0002] In recent years, technologies have been put into practical use in which an in-vehicle camera is mounted on the front window inside the vehicle, and the camera captures images to provide various information to the driver and perform vehicle control for driving assistance. However, this type of in-vehicle camera generates heat from the built-in controller or is exposed to direct sunlight in midsummer, and this can cause malfunctions due to heat damage.

[0003] To address this issue, for example, the technology disclosed in Patent Document 1 provides ventilation holes at the front and rear of the camera cover, and a portion of the conditioned air blown from the defroster and flowing along the windshield is introduced into the camera cover through one ventilation hole and discharged through the other ventilation hole. Patent Document 2 also provides a heat sink with fins at the bottom of the camera housing to promote heat dissipation. Patent Document 3 also provides a cooling fan built into the camera case to circulate air.

[0004] Japanese Patent Publication No. 2001-88611 Japanese Patent No. 6509256 Japanese Patent No. 7115093

[0005] In the technology described in Patent Document 1, conditioned air flowing along the windshield is introduced into the camera cover through the ventilation holes. Therefore, in order to introduce a sufficient amount of conditioned air, the ventilation holes on the intake side must be large and open. Furthermore, the heat sink described in Patent Document 2 requires a certain surface area for heat dissipation, and the cooling fan described in Patent Document 3 requires a certain fan diameter to ensure sufficient airflow, both of which contribute to the increase in size of the in-vehicle camera.

[0006] Furthermore, since the on-board camera is placed near the driver's head, its large size causes problems such as blocking the driver's forward field of view and reducing visibility. In addition, the operating noise of the cooling fan in Patent Document 3 is perceived as noise by passengers in the front seats, and the warm air after dissipating heat from the controller may hit the passenger's face, both of which can cause discomfort.

[0007] The present invention has been made to solve these problems, and its purpose is to provide a heat dissipation structure for an in-vehicle camera that can efficiently dissipate heat from the controller and reliably prevent malfunctions caused by heat damage, while avoiding the reduced visibility for the driver due to the larger size of the in-vehicle camera and the discomfort for passengers due to operating noise and warm air.

[0008] In order to achieve the above-mentioned object, the heat dissipation structure for an in-vehicle camera of the present invention is characterized by comprising: a camera casing for an in-vehicle camera that is fixed to the interior side of the vehicle's front window and that incorporates a camera unit that captures images in front of the vehicle and a camera controller that processes the captured images; a communication hole that penetrates the camera casing; a connection port that is provided in the camera casing; a headlining that covers the roof of the vehicle from the inside of the passenger compartment; an air conditioning unit that is arranged between the roof and the headlining and circulates air inside the passenger compartment using a blower fan through an air intake and exhaust port between a ventilation passage formed inside the air conditioning unit and the passenger compartment; and a duct that is arranged between the roof and the headlining and that connects the air intake and exhaust port of the air conditioning unit to the connection port of the camera casing.

[0009] With this heat dissipation structure for an in-vehicle camera, the air inside the vehicle cabin is circulated by the blower fan through the intake and exhaust ports between the ventilation passage of the air conditioning unit and the vehicle cabin. For example, the air inside the vehicle cabin may flow through the communication holes, the camera case, the duct, and the intake and exhaust ports in that order, or conversely, through the intake and exhaust ports, the duct, the camera case, and the communication holes. As a result, the camera controller is exposed to the air inside the vehicle cabin and dissipates heat.

[0010] In another aspect, a pair of left and right visor mounting portions to which sun visors are attached may be formed in the front portion of the headlining, and the duct may extend in a straight line from the connection port to the air supply / discharge port through the space between the pair of left and right visor mounting portions. Therefore, since a straight duct has low pipe resistance, the air inside the vehicle cabin can flow smoothly through the inside of the duct, allowing efficient heat dissipation of the camera controller.

[0011] In another aspect, a pair of left and right visor mounting portions to which sun visors are attached may be formed in the front portion of the headlining, and the duct may extend rearward from either the left or right visor mounting portion toward the vehicle width outside, and further extend to the air intake and exhaust port on the vehicle width outside of the headlining. Therefore, because the duct extends to the air intake and exhaust port on the vehicle width outside of the headlining, head clearance is ensured and the aesthetic appearance of the headlining is improved.

[0012] In another aspect, a pair of left and right visor mounting portions to which sun visors are attached may be formed in the front portion of the headlining, and the duct may extend from the front side of either the left or right visor mounting portion toward the outside of the vehicle width and further extend to the air intake and exhaust port on the outside of the vehicle width of the headlining. Therefore, since the duct extends to the air intake and exhaust port on the outside of the vehicle width of the headlining, head clearance is ensured and the aesthetic appearance of the headlining is improved.

[0013] In another aspect, a recess for preventing interference with the duct may be formed in a location of the headlining corresponding to the rear or front side of the visor attachment portion, thereby preventing interference between the headlining and the duct.

[0014] In another aspect, the air intake / exhaust port may be an intake port that draws in the interior air from the vehicle compartment and circulates it through the ventilation passage. Therefore, when the rear cooler unit is activated, negative pressure is generated at the intake port, and negative pressure also acts on the interior of the camera casing through the duct, and the camera controller is exposed to the interior air introduced into the camera casing through the communication hole, thereby dissipating heat.

[0015] In another aspect, the air intake / exhaust port may be an outlet that blows the interior air that has circulated through the ventilation passage into the interior of the vehicle. Thus, part of the interior air blown out from the outlet is introduced into the camera casing via a duct, and the camera controller is exposed to the interior air and dissipates heat.

[0016] In another aspect, the air intake and exhaust port may be an intake port that draws in the interior air from the vehicle compartment and circulates it through the ventilation passage, and an outlet port that blows the interior air that has circulated through the ventilation passage into the vehicle compartment, and the duct may be composed of a first duct that connects the intake port to the camera casing and a second duct that connects the outlet port to the camera casing. Thus, a portion of the interior air blown out from the outlet circulates through the second duct, the communication hole, the inside of the camera casing, the first duct, and the intake port in this order, and the camera controller is exposed to this interior air and dissipates heat.

[0017] In another aspect, a Venturi tube that widens toward the interior of the vehicle compartment may be disposed within the air intake, and the rear end of the duct may be connected to a portion of the Venturi tube that has the smallest diameter. As a result, part of the air in the vehicle compartment that is drawn into the air intake is drawn into the Venturi tube, and the pressure inside the Venturi tube decreases due to the Venturi effect, thereby increasing the negative pressure acting within the camera casing.

[0018] The heat dissipation structure for an in-vehicle camera of the present invention can prevent the driver's visibility from being reduced due to the larger size of the in-vehicle camera, and the discomfort to passengers caused by operating noise and warm air, while efficiently dissipating heat from the controller to reliably prevent malfunctions caused by heat damage.

[0019] 5 is a perspective view of the top surface of a headlining provided with a heat dissipation structure for an in-vehicle camera of a first embodiment, as seen from diagonally forward left; a cross-sectional view taken along line II-II of FIG. 1; a cross-sectional view taken along line III-III of FIG. 1; a flowchart showing a forced air blowing routine executed by a heat dissipation controller; a perspective view of the top surface of a headlining provided with a heat dissipation structure for an in-vehicle camera of a second embodiment, as seen from diagonally forward left; a partially cross-sectional perspective view showing details of part A of FIG. 5; a cross-sectional view taken along line VII-VII of FIG. 5; a perspective view of the top surface of a headlining provided with a heat dissipation structure for an in-vehicle camera of a third embodiment, as seen from diagonally forward left; a cross-sectional view taken along line IX-IX of FIG. 8;

[0020] [First embodiment] A first embodiment of a heat dissipation structure for an in-vehicle camera embodying the present invention will now be described. Fig. 1 is a perspective view of the top surface of a headlining provided with the heat dissipation structure for an in-vehicle camera, viewed diagonally from the front left, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, and Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. In the following description, front-rear, left-right, and up-down directions are expressed with reference to a passenger in the vehicle.

[0021] The heat dissipation structure 1 for an in-vehicle camera of this embodiment is provided between the roof 2 and headlining 3 of a vehicle. The headlining 3 is an interior material that covers the roof 2 from the interior E side of the vehicle and is formed with mounting portions for various components equipped in the interior E. For example, a pair of left and right visor mounting portions 5 to which sun visors 4 are fixed are formed in the front portion of the headlining 3, each of which is formed as a rectangular protrusion upward (toward the roof 2), and a rectangular lamp mounting portion 6 penetrates vertically between them. In addition, grip mounting portions 7 are formed on both the left and right sides of the headlining 3 at positions corresponding to the front seats, second-row seats, etc. When the headlining 3 is attached to the roof 2, as shown in FIG. 1 , the sun visors 4 are attached to the visor mounting portions 5, and although not shown, interior lights are attached to the lamp mounting portions 6 and assist grips are attached to the grip mounting portions 7.

[0022] The headlining 3 has a generally central portion in the longitudinal direction, specifically, a portion between the front seats and the second-row seats, which bulges downward (toward the interior E of the vehicle) across the entire width of the vehicle. This defines a unit housing 8 between the headlining 3 and the roof 2, within which a rectangular box-shaped rear cooler unit 9 (corresponding to the "air conditioning unit" of the present invention) is housed and fixed. As shown in FIG. 3 , the headlining 3 is generally close to the roof 2 (the region 19 directly above the front seats is illustrated in FIG. 2 ), but the bottom surface 8 a of the portion defining the unit housing 8 is located lower and further away from the roof 2. However, the aforementioned longitudinal positioning of the unit housing 8 ensures sufficient head clearance for occupants seated in the front seats and the second-row seats.

[0023] An air passage 10 extending in the front-to-rear direction is formed within the rear cooler unit 9, and although not shown, a blower fan, a cooling evaporator, and the like are disposed within the air passage 10. The front end of the air passage 10 opens forward as an intake port 10f (corresponding to the "supply / exhaust port" of the present invention), and the rear end of the air passage 10 opens rearward as an outlet port 10r (corresponding to the "supply / exhaust port" of the present invention). The intake port 10f and the outlet port 10r communicate with the vehicle interior E via through-holes 11f, 11r, respectively, which are provided through the front and rear surfaces of the unit housing portion 8.

[0024] The operating state of the rear cooler unit 9 is controlled by an air conditioning controller 12 based on the operation of an operation panel (not shown) and the vehicle interior temperature detected by a vehicle interior temperature sensor. For example, in the blowing mode, the blower fan is operated to draw in vehicle interior air through the intake port 10f, circulate it through the ventilation duct 10, and then blow it out into the vehicle interior E through the outlet port 10r, thereby circulating the vehicle interior air between the vehicle interior E and the ventilation duct 10. In the cooling mode, in addition to the blowing air in the blowing mode, refrigerant from an air conditioning system (not shown) is supplied to the evaporator to cool the vehicle interior air, thereby cooling the vehicle interior E.

[0025] Meanwhile, an on-board camera 15 is fixed by a bracket (not shown) to the center of the upper left and right sides of the windshield 13 inside the passenger compartment E. The camera casing 16 of the on-board camera 15 is shaped like a square box, and houses a CCD camera 17 (corresponding to the "camera unit" of the present invention) that captures images in front of the vehicle, and a camera controller 18 that processes the images captured by the CCD camera. The processed image information is output to a main controller (not shown) of the vehicle, and is used, for example, to present information about road signs in front of the vehicle to the driver or to execute vehicle control to prevent lane departure. Of course, the use of the image information is not limited to this and can be changed as desired.

[0026] The above configuration is similar to that of a typical vehicle. Next, a configuration related to the features of this embodiment will be described. As previously mentioned, the camera controller 18 in the camera casing 16 generates heat as it executes its calculations, and the temperature of the camera casing 16 rises when exposed to strong direct sunlight, especially in midsummer. This can lead to malfunction of the camera controller 18 due to heat damage. To address this issue, the technologies disclosed in Patent Documents 1 to 3 incorporate ventilation holes, heat sinks, cooling fans, and other measures. However, these technologies have drawbacks, such as a larger onboard camera 15 impairing the driver's visibility and the noise and warm air from the fan causing discomfort to front-seat passengers.

[0027] In consideration of such problems, the heat dissipation structure 1 for the vehicle-mounted camera 15 of this embodiment is designed to dissipate heat from the camera controller 18 by utilizing the air inside the vehicle cabin that is sucked into the rear cooler unit 9, and the details of this structure are described below.

[0028] As described above, most of the area of ​​the headlining 3 is close to the roof 2, and the areas 19 located directly above the left and right front seats shown in Fig. 1 (hereinafter referred to as the areas directly above the front seats) are also close to the roof 2. Behind this area 19 directly above the front seats, a unit accommodating section 8 having a bottom surface 8a spaced further downward from the roof 2 is formed, while in front of the area 19 directly above the front seats, a visor area 20 is formed that is located slightly below the area 19 directly above the front seats in order to form a visor mounting portion 5 that protrudes upward.

[0029] 2, a plurality of slits 16a (corresponding to "communication holes" of the present invention) are formed in the lower rear side of the camera casing 16 of the vehicle-mounted camera 15, and the interior of the camera casing 16 communicates with the vehicle interior E through these slits 16a. Furthermore, a connection port 16b that protrudes rearward is integrally formed in the upper rear side of the camera casing 16, and the cross-sectional shape of the connection port 16b corresponds to the cross-sectional shape of a duct 21 described below. As shown in FIG. 2, the connection port 16b is located at approximately the same height as the intake port 10f of the rear cooler unit 9, and the intake port 10f and the connection port 16b are connected via the duct 21 that extends in the fore-and-aft direction.

[0030] The duct 21 has a linear shape extending in the front-rear direction in the side view shown in Fig. 2, and also has a linear shape extending in the front-rear direction between the left and right visor mounting portions 5 in the plan view as shown in Fig. 1. As shown in Fig. 3, the duct 21 is formed by the cooperation of a synthetic resin cover member 21a and the headlining 3. More specifically, the cross section of the cover member 21a is concave downward, and its lower edge is bonded onto the headlining 3 to close it, thereby forming the cross section of the duct 21.

[0031] The front end of the duct 21 is inserted into and fixed to the connection port 16b, and the duct 21 extends rearward from the connection port 16b, passing through the visor region 20 and the region 19 directly above the front seats to reach the air intake 10f, with its opening facing the air intake 10f. Because the visor region 20 is located at the same height as the lower edge of the cover member 21a, the visor region 20 closes the cover member 21a from below while maintaining its original shape. In contrast, because the region 19 directly above the front seats is located higher, a linear groove 22 extending in the fore-and-aft direction is formed in the upper surface of the region 19 directly above the front seats, and the cover member 21a is disposed within this groove 22 to form the duct 21.

[0032] When the rear cooler unit 9 operates in the blowing mode or the cooling mode, negative pressure is generated in the air inlet 10f, and this negative pressure acts on the opening of the duct 21 disposed opposite the air inlet 10f. As a result, negative pressure also acts on the camera casing 16 via the duct 21, and the air in the vehicle compartment is introduced into the camera casing 16 through the slit 16a, flows through the duct 21, and then flows into the air inlet 10f. The air in the vehicle compartment that flows into the air inlet 10f via the duct 21 merges with the air that has flowed directly into the air inlet 10f from the vehicle interior E, and then flows through the ventilation passage 10 to the outlet 10r.

[0033] As a result, the camera controller 18 is exposed to the air inside the vehicle cabin inside the camera casing 16. For example, when the computation load on the camera controller 18 is excessive, or when it is exposed to strong direct sunlight such as in midsummer, the temperature of the camera controller 18 rises significantly compared to the temperature of the air inside the vehicle cabin, but by being exposed to the air inside the vehicle cabin, heat is efficiently dissipated and the temperature drops.

[0034] Meanwhile, the air inside the vehicle compartment for dissipating heat from the vehicle-mounted camera 15 is controlled by a heat dissipation controller 23. A temperature sensor 24 is connected to the input side of the heat dissipation controller 23, and information relating to the temperature T inside the camera casing 16 detected by this temperature sensor 24 is input to the heat dissipation controller 23. The air conditioning controller 12 is also connected to the output side of the heat dissipation controller 23, and the air conditioning controller 12 controls the rear cooler unit 9 based on commands input from the heat dissipation controller 23, separately from the original control based on the operation of the operation panel, the vehicle compartment temperature, etc.

[0035] 4 is a flowchart showing a forced airflow routine executed by the heat dissipation controller 23. When the vehicle ignition switch is turned on, the heat dissipation controller 23 executes this routine at predetermined control intervals. First, in step S1, it is determined whether the rear cooler unit 9 is operating. "Operating" refers to a state in which the airflow fan is operating and circulating air inside the vehicle cabin through the ventilation duct 10, regardless of whether the rear cooler unit 9 is in the airflow mode or the cooling mode. If the determination in step S1 is Yes (affirmative), the routine ends. If the determination is No (negative), the routine proceeds to step S2. In step S2, it is determined whether the temperature T is equal to or higher than a predetermined threshold temperature T0, and if No, the routine ends. The threshold temperature T0 is a threshold value set slightly lower than the upper limit temperature at which the camera controller 18 functions normally.

[0036] If step S1 is Yes, it can be assumed that the camera controller 18 continues to be exposed to the cabin air circulating through the camera casing 16 as described above. Therefore, even if heat dissipation is required (if step S2 is Yes), if the system remains in standby mode, the camera controller 18 will gradually dissipate heat and its temperature will drop without any problems. If step S2 is No, it can be assumed that heat dissipation from the camera controller 18 is not required, so there will be no problems even if the system remains in standby mode. On the other hand, if step S2 is Yes, it is assumed that heat dissipation is required to prevent heat damage to the camera controller 18, and the system proceeds to step S3, where a command to force airflow is output to the air conditioning controller 12, and the routine then ends.

[0037] In response to this command, the air conditioning controller 12 forcibly operates the rear cooler unit 9 to blow air. The air blowing at this time may be performed in either a ventilation mode or a cooling mode. Since the camera controller 18 is exposed to the cabin air circulating within the camera casing 16, the camera controller 18 dissipates heat and its temperature drops, thereby reliably preventing malfunctions due to heat damage.

[0038] Since the rear cooler unit 9 is stopped before receiving the command, it can be assumed that the occupant does not want air conditioning. In view of this, it is desirable to select the fan mode to prevent the temperature inside the vehicle cabin from dropping excessively.

[0039] As described above, according to this embodiment, when it is determined that heat dissipation from the camera controller 18 is required based on the temperature T inside the camera casing 16, the rear cooler unit 9 is automatically activated to dissipate heat, thereby reliably preventing malfunction of the vehicle-mounted camera 15 due to heat damage. Meanwhile, according to the heat dissipation structure 1 for the vehicle-mounted camera 15 of this embodiment, heat is dissipated from the vehicle-mounted camera 15 using the air inside the vehicle compartment that is drawn into the rear cooler unit 9, thereby solving the problems encountered in Patent Documents 1 to 3.

[0040] First, it is possible to prevent the camera casing 16 from becoming large. Specifically, the camera casing 16 of this embodiment does not have the ventilation holes on the inlet side of Patent Document 1, which would increase the size. Furthermore, the camera casing 16 does not have any built-in components equivalent to the heat sink portion of Patent Document 2 or the cooling fan of Patent Document 3, which would also increase the size.

[0041] In this embodiment, a connection port 16b for inserting and fixing the front end of the duct 21 must be formed in the camera casing 16 so that the negative pressure generated at the intake port 10f of the rear cooler unit 9 can be applied to the inside of the camera casing 16. However, since the connection port 16b is a very small portion, it does not increase the size of the camera casing 16, and it does not increase the size of the slit 16a for introducing air into the vehicle cabin either. Therefore, the on-board camera 15 can be placed without obstructing the driver's forward view, thereby achieving good visibility.

[0042] Furthermore, since the camera casing 16 does not have a built-in cooling fan, no operating noise is generated, and although the air inside the vehicle cabin is drawn into the camera casing 16 through the slits 16a, no warm air is blown out after dissipating heat from the camera controller 18. Therefore, discomfort to the occupants caused by these operating noises and warm air can be avoided in advance.

[0043] In addition, in a plan view, the duct 21 is formed in a straight line extending forward and backward between the left and right visor mounting portions 5, so there are no bends and the pipe resistance is low. Therefore, the air inside the vehicle cabin can be smoothly circulated to the intake port 10f side through the duct 21, and sufficient negative pressure can be applied inside the camera casing 16, thereby achieving the effect of efficiently dissipating heat from the camera controller 18.

[0044] Meanwhile, vehicles are often destined for a wide variety of destinations, including some that require the heat dissipation structure 1 of the present embodiment and some that do not require the heat dissipation structure 1. Equipping vehicles for all destinations with the heat dissipation structure 1 would result in unnecessary cost increases for vehicles destined for destinations that do not require the heat dissipation structure 1, and producing vehicles with and without the heat dissipation structure 1 depending on the destination would also result in cost increases.

[0045] On the other hand, situations requiring heat dissipation from the camera controller 18 occur frequently in environments where the outside air temperature is high and the vehicle is exposed to strong direct sunlight, such as hot regions, but do not occur in cold regions. Furthermore, vehicles intended for hot regions often already have a rear cooler unit 9 or a circulator unit (with only a blowing function) installed in the roof 2 at the request of customers. Therefore, by using such an existing vehicle as a base and making minor specification changes, such as adding a duct 21 or modifying the shape of the headlining 3 and the camera casing 16, a vehicle equipped with the heat dissipation structure 1 can easily be made. On the other hand, vehicles intended for cold regions do not have a rear cooler unit 9 or the like, but do not require the heat dissipation structure 1 in the first place, so there is no need to add such a structure. As a result, unnecessary additional equipment such as the rear cooler unit 9 can be prevented, and the heat dissipation structure 1 for the camera controller 18 can be equipped in the vehicle with minimal specification changes as needed.

[0046] [Second embodiment] Next, a second embodiment of the heat dissipation structure 1 for an in-vehicle camera 15 embodying the present invention will be described. Fig. 5 is a perspective view of the upper surface of a headlining 3 provided with the heat dissipation structure 1 for an in-vehicle camera 15, viewed from diagonally forward left, Fig. 6 is a partial cross-sectional perspective view showing details of part A in Fig. 5, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 5.

[0047] The differences from the first embodiment are that the configuration and routing of the duct 31 have been changed, and that the negative pressure generated in the Venturi tube is applied to the inside of the camera casing 16 via the duct 31. Therefore, the same component numbers are used for the common configuration parts, and the explanation will be omitted, and the differences will be mainly described.

[0048] In this embodiment, the duct 31 is manufactured as an independent synthetic resin pipe material, separate from the headlining 3. The duct 31 is fixed to the underside of the roof 2 by a plurality of pipe holders 32 spaced apart in the longitudinal direction. As shown in an example in Figure 7, the pipe holder 32 is made of a synthetic resin material and integrally formed with a plate-shaped base portion 32a and an annular holder portion 32b having a notch. The base portion 32a of each pipe holder 32 is fixed to a predetermined position on the underside of the roof 2, and the duct 31 is fitted into the holder portion 32b via the notch, thereby fixing the duct 31 to the roof 2 along a predetermined path.

[0049] The connection port 16b of the camera casing 16 has a circular cross section corresponding to the cross section of the duct 31, and the front end of the duct 31 is inserted and fixed into the connection port 16b. The duct 31 extends rearward from the connection port 16b, bends leftward at a right angle, and extends leftward (corresponding to the "outside of the vehicle width" of the present invention) behind the left visor attachment portion 5. The duct 31 further bends rearward at a right angle, extends rearward on the left side of the area 19 directly above the front seats (corresponding to the "outside of the vehicle width" of the present invention), bends rightward, and its rear end is inserted into the intake port 10f of the rear cooler unit 9.

[0050] As shown in Figure 7, a recess 33 having a semicircular cross section and bulging downward is formed in the visor region 20 at a location corresponding to the rear side of the visor mounting portion 5, thereby preventing interference with the duct 31.

[0051] In addition, the routing path of the duct 31 may be changed to be symmetrical on both sides, with the rear side of the right-side visor mounting portion 5 extended to the right (corresponding to the "outside of the vehicle width" in this invention), and the right side of the area 19 directly above the front seat (corresponding to the "outside of the vehicle width" in this invention) extended toward the rear.

[0052] A Venturi tube 34 is disposed within the air intake 10f. The Venturi tube 34 is cylindrical and widens toward the front, specifically, has a maximum inner diameter on the vehicle interior E side and gradually decreases toward the ventilation passage 10 side. The rear end of the duct 31 inserted into the air intake 10f is connected to the portion of the Venturi tube 34 with the smallest diameter.

[0053] When the blower fan of the rear cooler unit 9 is activated, air in the vehicle cabin is drawn into the air intake 10f, and some of the air is drawn into the Venturi tube 34. In the Venturi tube 34, the Venturi effect reduces the cross-sectional area of ​​the passage, increasing the flow velocity of the air in the vehicle cabin, and causing a corresponding drop in pressure. As a result, negative pressure is generated in the Venturi tube 34 within the air intake 10f, i.e., a negative pressure higher than that in the first embodiment. This negative pressure then acts on the camera casing 16 via the duct 31, as in the first embodiment, and, although a redundant description will not be provided, this negative pressure dissipates heat from the camera controller 18.

[0054] Although the Venturi tube 34 is provided in the air intake 10f, the air inside the vehicle compartment that has flowed through the Venturi tube 34 flows into the ventilation passage 10 together with the air inside the vehicle compartment that has been directly drawn into the air intake 10f. This allows a higher negative pressure to be generated without reducing the air-blowing capacity or cooling capacity of the rear cooler unit 9.

[0055] The duct 21 in the first embodiment took a path that crossed the area 19 directly above the front seats from front to back, which required the formation of a deep groove 22 in the area 19 directly above the front seats in order to accommodate the duct 21. The groove 22 protruded toward the interior E of the vehicle, which reduced head clearance and impaired the aesthetic appearance of the headlining 3. In contrast, the duct 31 in this embodiment extends rearward on the left side of the area 19 directly above the front seats, which allows the original shape of the area 19 directly above the front seats without the groove 22 to be maintained, thereby achieving the effects of ensuring head clearance and improving the aesthetic appearance of the headlining 3.

[0056] While this has advantages, the path of duct 31 becomes more complex, and the number of bends increases, resulting in increased pipe resistance. Negative pressure within camera casing 16 is generated by circulating cabin air toward intake port 10f through duct 31. Therefore, increased pipe resistance results in insufficient negative pressure acting within camera casing 16, which in turn leads to insufficient cabin air being introduced into camera controller 18 through slit 16a, and ultimately to insufficient heat dissipation from camera controller 18.

[0057] To address this issue, the present embodiment uses a Venturi tube 34 to increase the negative pressure. This allows a high negative pressure comparable to that of the first embodiment to be applied inside the camera casing 16, thereby efficiently dissipating heat from the camera controller 18. However, depending on the cross-sectional area and length of the duct 31, it may be possible to apply a sufficient negative pressure inside the camera casing 16 without providing the Venturi tube 34. In such cases, the Venturi tube 34 may be omitted.

[0058] [Third embodiment] Next, a third embodiment of the heat dissipation structure 1 for an in-vehicle camera 15 embodying the present invention will be described. Fig. 8 is a perspective view of the top surface of a headlining 3 provided with the heat dissipation structure 1 for an in-vehicle camera 15 of the third embodiment, viewed from diagonally forward left, and Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Note that Fig. 6, which was used to explain the second embodiment, is also common to this embodiment.

[0059] The difference from the second embodiment is that the routing path of the duct 41 has been changed. Since the Venturi tube 34 and the like are common, the same component numbers are used for the common components, and explanations are omitted, and the differences are mainly described.

[0060] 8 and 9 , the duct 41 of this embodiment extends in the left-right direction in front of the left visor attachment portion 5. Specifically, the duct 41 extends rearward from the connection port 16b, bends leftward at a right angle, and extends leftward (corresponding to the "outside of the vehicle width" in this invention) from the front side of the left visor attachment portion 5. The duct 41 further bends rearward at a right angle and extends rearward from the left side of the area 19 directly above the front seats (corresponding to the "outside of the vehicle width" in this invention), bends rightward, and its rear end is inserted into the intake port 10f of the rear cooler unit 9. Naturally, a relief portion 42 for preventing interference with the duct 41 is formed in the visor area 20 at a location corresponding to the front side of the visor attachment portion 5.

[0061] 5 and 7, the relief portion 33 in the second embodiment is provided on the rear side of the visor attachment portion 5, in other words, in a position close to the occupant's head, which may cause a slight feeling of oppression to the occupant and also leaves room for improvement in terms of aesthetics. In contrast, in this embodiment, the relief portion 42 is formed in a position farther away from the occupant's head, which reduces the feeling of oppression, and since the relief portion 42 is the sun visor 4 when viewed from the occupant's side, it is possible to prevent a deterioration in aesthetics.

[0062] Although the description of the embodiment is now complete, aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the camera controller 18 is dissipated heat by utilizing the negative pressure generated at the intake port 10f of the rear cooler unit 9. However, this is not limited to the rear cooler unit 9, and the negative pressure of the circulator described above may also be utilized. Since this is common to the rear cooler unit 9, a redundant description will not be given, but the structure is such that the negative pressure generated at the intake port of the circulator is applied to the inside of the camera casing 16 via a duct.

[0063] In the above embodiment, negative pressure is applied inside the camera casing 16 by connecting the connection port 16b of the camera casing 16 to the air intake port 10f of the cooling unit via the ducts 21, 31, and 41. However, this is not limiting. For example, the connection port 16b of the camera casing 16 may be connected to the air outlet 10r of the rear cooling unit 9 via a duct. In this case, a portion of the air inside the vehicle cabin blown out from the air outlet 10r is introduced into the camera casing 16 via the duct and then discharged into the vehicle cabin E through the slit 16a. As a result, the camera controller 18 is exposed to the air inside the vehicle cabin and dissipates heat, as in the above embodiment, thereby achieving the various effects described above.

[0064] Alternatively, as in the above embodiment, the connection port 16b of the camera casing 16 may be connected to the intake port 10f of the rear cooler unit 9 via the ducts 21, 31, and 41 (corresponding to the "first duct" of the present invention), and the slit 16a of the camera casing 16 may be connected to the outlet 10r of the rear cooler unit 9 via another duct (corresponding to the "second duct" of the present invention). In this case, a portion of the air in the vehicle cabin blown out from the outlet 10r of the rear cooler unit 9 circulates through the other duct, the slit 16a, the inside of the camera casing 16, the ducts 21, 31, and 41, and the intake port 10f in this order, thereby dissipating heat from the camera controller 18 within the camera casing 16. In this case, the same various effects as those of the above embodiment can be achieved.

[0065] REFERENCE SIGNS LIST 1 heat dissipation structure 2 roof 3 headlining 4 sun visor 5 visor mounting portion 9 rear cooler unit (air conditioning unit) 10 ventilation duct 10a intake port (intake / exhaust port) 10b outlet port (intake / exhaust port) 13 front window 15 vehicle-mounted camera 16 camera casing 16a slit (communication hole) 16b connection port 17 CCD camera (camera unit) 18 camera controller 21, 31, 41 duct (first duct) 33, 42 relief portion 34 Venturi tube

Claims

1. A heat dissipation structure for an in-vehicle camera comprising: a camera casing for an in-vehicle camera fixed to the interior side of the vehicle's front windshield and incorporating a camera unit that captures images of the area in front of the vehicle and a camera controller that processes the captured images; a communication hole formed through the camera casing; a connection port provided in the camera casing; a headlining that covers the roof of the vehicle from the inside of the passenger compartment; an air conditioning unit arranged between the roof and the headlining and circulating air inside the passenger compartment via an air intake and exhaust port using a blower fan between an air passage formed inside the unit and the passenger compartment; and a duct arranged between the roof and the headlining and connecting the air intake and exhaust port of the air conditioning unit to the connection port of the camera casing.

2. The heat dissipation structure for an in-vehicle camera according to claim 1, characterized in that a pair of left and right visor mounting portions for mounting sun visors are formed in the front part of the headlining, and the duct extends in a straight line from the connection port to the intake and exhaust port, passing between the pair of left and right visor mounting portions.

3. The heat dissipation structure for an in-vehicle camera according to claim 1, characterized in that a pair of left and right visor mounting portions to which sun visors are attached are formed in the front part of the headlining, and the duct extends from the rear side of either the left or right visor mounting portion toward the outside of the vehicle width, and further extends outside the vehicle width of the headlining to the intake and exhaust port.

4. The heat dissipation structure for an in-vehicle camera described in claim 1, characterized in that a pair of left and right visor mounting portions to which sun visors are attached are formed in the front part of the headlining, and the duct extends from the front side of either the left or right visor mounting portion toward the outside of the vehicle width, and further extends outside the vehicle width of the headlining to the intake and exhaust port.

5. The heat dissipation structure for an in-vehicle camera according to claim 3 or 4, characterized in that a relief portion is formed in a location corresponding to the rear or front side of the visor mounting portion of the headlining to prevent interference with the duct.

6. The heat dissipation structure for an in-vehicle camera according to claim 1, characterized in that the air intake and exhaust port is an intake port that draws in air from inside the vehicle compartment and circulates it through the ventilation path.

7. The heat dissipation structure for an in-vehicle camera according to claim 1, characterized in that the air intake and exhaust port is an outlet that blows the air inside the vehicle compartment that has circulated through the ventilation passage into the vehicle compartment.

8. The heat dissipation structure for an in-vehicle camera described in claim 1, characterized in that the air intake and exhaust ports are an intake port that draws in the air inside the vehicle cabin from inside the vehicle cabin and circulates it through the ventilation duct, and an outlet port that blows the air inside the vehicle cabin that has circulated through the ventilation duct into the vehicle cabin, and the duct consists of a first duct that connects the intake port to the camera casing, and a second duct that connects the outlet port to the camera casing.

9. The heat dissipation structure for an in-vehicle camera described in claim 6, characterized in that a Venturi tube that widens toward the interior of the vehicle is arranged inside the air intake, and the rear end of the duct is connected to the part of the Venturi tube with the smallest diameter.

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