Cooling device for marine propulsion engines

Abstract

To provide a cooling device for a ship propulsion machine to facilitate the maintenance of a collector for collecting micro objects while suppressing the deterioration of a cooling-water flow.SOLUTION: A collector 31 to collect micro-objects in the cooling-water flowing in a drain passage 27 is provided between the upstream part 27A and the downstream part 27B of the drain passage 27 in an outboard engine cooling device. The collector 31 has a filter cartridge 32, a case 41 to accommodate the filter cartridge 32, a branch pipe 53 to connect the upstream part 27A of the drain passage 27 and the case 41, and a connection hose 54 and a junction pipe 55 to connect the case 41 and the downstream part 27B of the drain passage 27. The connection hose 54 extends non-linearly in the vertical direction by bending at an upper side bending part 54A and at a lower side bending part 54B, and the length of the connection hose 54 is longer than the length of the branch pipe 53.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a cooling device for a marine propulsion machine that has a function of collecting fine particles dispersed in water such as seawater or lake water. [Background technology]

[0002] In recent years, pollution of oceans, lakes, rivers, etc. caused by the dispersion of fine debris such as microplastics into seawater, lake water, river water, etc. has become a problem. It is also known that seas, lakes, rivers, etc. are polluted by the dispersion of residues of feed used in aquaculture into seawater, lake water, river water, etc. In order to prevent such pollution, it is desirable to capture and recover fine debris such as microplastics, residues of feed, etc. (hereinafter referred to as "fine objects").

[0003] The following Patent Document 1 describes an outboard motor equipped with a cooling device that has a function of capturing fine particles. The cooling device uses a pump to draw water, such as seawater or lake water, into the outboard motor and supplies the drawn water as cooling water to a water jacket attached to the engine of the outboard motor. The cooling water supplied to the water jacket flows through the water jacket, thereby cooling the engine. After flowing through the water jacket, the cooling water also flows through a drain pipe, passes through a filter device attached midway through the drain pipe, and is then discharged outside the outboard motor. As the cooling water passes through the filter device, fine particles in the cooling water are captured by the filter device and removed from the cooling water. In this way, the cooling device allows seawater, lake water, etc. to be drawn into the outboard motor and fine particles contained in the drawn seawater, lake water, etc. to be captured by the filter device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-163872 Summary of the Invention [Problem to be solved by the invention]

[0005] FIG. 9(A) shows the drain pipe and filtration device in the cooling device shown in FIG. 3 of Patent Document 1. In FIG. 9(A), 133 is the drain pipe and 135 is the filtration device. FIG. 9(B) shows the drain pipe 133 and filtration device 135 in FIG. 9(A) as viewed from the direction indicated by arrow S in FIG. 9(A). In FIGS. 9(A) and 9(B), arrow X indicates the flow direction of cooling water in drain pipe 133 and filtration device 135. As shown in FIG. 9(B), in the cooling device of Patent Document 1, the cooling water flows through filtration device 135 while bending significantly, which may increase pressure loss in the cooling water flow path and impair the flow of cooling water.

[0006] Therefore, in order to suppress an increase in pressure loss in the cooling water flow path, one possible method is to divide the drain passage, which sends the cooling water after circulating inside the water jacket to the drain port of the outboard motor, into an upper drain passage section 201 and a lower drain passage section 202, and to arrange the filter device 203 between the upper drain passage section 201 and the lower drain passage section 202, coaxially with the upper drain passage section 201 and the lower drain passage section 202, as shown in Figure 10. With this method, as indicated by arrow Y in Figure 10, the cooling water flows linearly through the upper drain passage section 201, the filter device 203, and the lower drain passage section 202, thereby suppressing an increase in pressure loss in the cooling water flow path and improving the flow of the cooling water.

[0007] However, if the filtration device 203 is arranged coaxially between the upper drainage passage section 201 and the lower drainage passage section 202, it becomes difficult to remove the filtration device 203 from between the upper drainage passage section 201 and the lower drainage passage section 202, which creates the problem that maintenance of the filtration device 203 (for example, removing fine objects accumulated in the filter) becomes difficult.

[0008] That is, the lower end of the upper drain passage portion 201 is inserted into and fitted into the upper part of the filtration device 203, and the upper end of the lower drain passage portion 202 is inserted into and fitted into the lower part of the filtration device 203. Therefore, in order to remove the filtration device 203 from between the upper drain passage portion 201 and the lower drain passage portion 202, it is necessary to be able to move the filtration device 203 in the vertical direction relative to the upper drain passage portion 201 or the lower drain passage portion 202, for example, by moving the filtration device 203 downward relative to the lower end of the upper drain passage portion 201 so that the upper drain passage portion 201 and the filtration device 203 can be separated, or by moving the filtration device 203 upward relative to the upper end of the lower drain passage portion 202 so that the lower drain passage portion 202 and the filtration device 203 can be separated. However, if the upper drain passage portion 201 and the lower drain passage portion 202 are made of highly rigid pipes or hoses, it is difficult to move the filtration device 203 sandwiched between the upper drain passage portion 201 and the lower drain passage portion 202 upward or downward. Therefore, it is difficult to remove the filtration device 203 from between the upper drain passage portion 201 and the lower drain passage portion 202.

[0009] In this regard, if a low-rigidity rubber hose or the like is used as the upper drain passage portion 201 or the lower drain passage portion 202, the filtration device 203 can be easily removed from between the upper drain passage portion 201 and the lower drain passage portion 202 by bending the rubber hose by hand. However, the upper drain passage portion 201 and the lower drain passage portion 202 must have high durability against vibration, impact, heat, and the like. Therefore, even when a rubber hose is used as the upper drain passage portion 201 or the lower drain passage portion 202, it is necessary to use, for example, a rubber hose containing reinforced fibers or a rubber hose with a thick wall, which results in high rigidity of the rubber hose. In other words, in order to meet the need to increase the durability of the upper drain passage portion 201 and the lower drain passage portion 202, it is difficult to use a low-rigidity rubber hose or the like that can be easily bent by hand as the upper drain passage portion 201 or the lower drain passage portion 202.

[0010] The present invention has been developed in consideration of problems such as those described above, and an object of the present invention is to provide a cooling device for a marine propulsion unit that can suppress deterioration of the flow of cooling water while facilitating maintenance of a collector (filtering device) that captures fine objects. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention Cooling device for a first marine propulsion unit is a cooling device for a marine propulsion unit that is provided in a marine propulsion unit, takes in water from outside the marine propulsion unit into the marine propulsion unit, flows the taken-in water around or inside a power source of the marine propulsion unit as cooling water to cool the power source, and discharges the cooling water after flowing around or inside the power source to the outside of the marine propulsion unit, the cooling device comprising: a drainage passage for discharging the cooling water after flowing around or inside the power source to the outside of the marine propulsion unit; and a collector that is interposed between an upstream portion and a downstream portion of the drainage passage and that collects fine particles contained in the cooling water that flows from the upstream portion of the drainage passage to the downstream portion of the drainage passage. , bypass passage and the collector comprises a collector body that captures the fine objects and allows cooling water to pass through; a case that can be separated into an upper and lower section and that houses the collector body; an upper connecting pipe that extends in the vertical direction, has an upper end connected to the upstream portion of the drain passage and a lower end connected to the upper portion of the case, and allows cooling water to flow from the upstream portion of the drain passage into the case; and a flexible lower connecting pipe that has an upper end connected to the lower portion of the case and a lower end connected to the downstream portion of the drain passage, and allows cooling water to flow from the case to the downstream portion of the drain passage. The bypass passage is a passage that bypasses the collector body and the lower connecting pipe, and is a portion of the lower connecting pipe that is located between an upper end of the lower connecting pipe and a junction where the lower connecting pipe and the bypass passage join together. a bending portion is provided at the lower connecting pipe, the lower connecting pipe extends non-linearly in the vertical direction by bending at the bending portion, and the length of the lower connecting pipe is longer than the length of the upper connecting pipe. A second cooling device for a marine propulsion unit of the present invention is a cooling device for a marine propulsion unit that is provided in a marine propulsion unit, and that takes in water from outside the marine propulsion unit into the marine propulsion unit, flows the taken-in water around or inside a power source of the marine propulsion unit as cooling water to cool the power source, and discharges the cooling water after flowing around or inside the power source to the outside of the marine propulsion unit, and is equipped with a drainage passage for discharging the cooling water after flowing around or inside the power source to the outside of the marine propulsion unit, and a collector that is interposed between an upstream portion and a downstream portion of the drainage passage and that collects fine matter contained in the cooling water that flows from the upstream portion of the drainage passage to the downstream portion of the drainage passage, and the collector comprises a collector body that captures the fine matter and allows the cooling water to pass through, a case that is formed so as to be separable into an upper portion and a lower portion and that houses the collector body, and a vertically extending case that has an upper end connected to the upstream portion of the drainage passage and a lower end connected to the upper portion of the case, and The collector comprises an upper connecting pipe that flows cooling water from the upstream portion of the water passage into the case, and a flexible lower connecting pipe whose upper end is connected to the lower portion of the case and whose lower end is connected to the downstream portion of the drain passage, and which flows cooling water from the case to the downstream portion of the drain passage, wherein a bent portion is provided between the upper and lower ends of the lower connecting pipe, and the lower connecting pipe extends non-linearly in the vertical direction by bending at the bent portion, and the length of the lower connecting pipe is longer than the length of the upper connecting pipe, and the case comprises an upper case portion that forms the upper portion of the case and to which the lower end of the upper connecting pipe is connected, and a lower case portion that forms the lower portion of the case and to which the upper end of the lower connecting pipe is connected and is separably connected to the upper case portion in the vertical direction, and when the lower case portion is connected to the upper case portion, the upper end of the lower case portion is located below the vertical center of the collector body. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress deterioration of the flow of cooling water and facilitate maintenance of a collector that collects fine objects. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an overall view showing an outboard motor provided with a cooling device according to an embodiment of the present invention; [Figure 2] 1 is an external view showing an engine of an outboard motor according to an embodiment of the present invention as viewed from the left side. FIG. [Figure 3] FIG. 3 is an external view showing the engine in FIG. 2 as seen from the rear. [Figure 4] 1 is an explanatory diagram showing the configuration of a cooling device according to an embodiment of the present invention; [Figure 5] 4 is a cross-sectional view taken along the cutting line VV in FIG. 3, showing the upstream portion of the drainage passage, the collector, the downstream portion of the drainage passage, and the bypass passage. [Figure 6] 6 is an enlarged cross-sectional view of the case and the filter cartridge in FIG. 5. FIG. [Figure 7] 10A and 10B are explanatory views showing a method for separating the lower case portion from the upper case portion and removing the filter cartridge from the upper case portion in the embodiment of the present invention. [Figure 8] 8 is a cross-sectional view showing the connection hose, the bypass pipe, etc., taken along the line VIII-VIII in FIG. 5, as viewed from above. [Figure 9] FIG. 10 is an explanatory diagram showing a drainage pipe and a filtering device in a conventional cooling device. [Figure 10] FIG. 2 is an explanatory diagram showing a filter device and a drainage passage portion arranged coaxially with each other. DETAILED DESCRIPTION OF THE INVENTION

[0014] A cooling device for a marine propulsion unit according to an embodiment of the present invention is a cooling device that is installed in a marine propulsion unit, takes in water from outside the marine propulsion unit into the marine propulsion unit, cools the power source by flowing the taken-in water around or inside the power source of the marine propulsion unit as cooling water, and discharges the cooling water after flowing around or inside the power source outside the marine propulsion unit.The cooling device is equipped with a drainage passage for discharging the cooling water after flowing around or inside the power source outside the marine propulsion unit, and a collector interposed between the upstream and downstream portions of the drainage passage and for collecting fine particles contained in the cooling water flowing from the upstream portion of the drainage passage toward the downstream portion of the drainage passage.

[0015] The collector also includes a collector body that captures fine objects and allows cooling water to pass through, a case that is formed in a cylindrical shape with an axis extending in the vertical direction and that houses the collector body, an upper connecting pipe that extends in the vertical direction and has an upper end connected to the upstream part of the drainage passage and a lower end connected to the top of the case, and that allows cooling water to flow from the upstream part of the drainage passage into the case, and a flexible lower connecting pipe that has an upper end connected to the bottom of the case and a lower end connected to the downstream part of the drainage passage, and that allows cooling water to flow from the case to the downstream part of the drainage passage.

[0016] The lower connecting pipe has a first bent portion between its upper end and lower end, and a second bent portion between its first bent portion and lower end. The lower connecting pipe extends downward from its upper end along the axis of the case, then bends at the first bent portion, then extends downward while inclined relative to the axis of the case and away from the axis of the case, then bends at the second bent portion, and then extends downward while inclined relative to the axis of the case and towards the axis of the case.

[0017] In the cooling device of this embodiment, the case is formed in a cylindrical shape with an axis extending vertically, and the upper connecting pipe extends vertically between the upstream portion of the drain passage and the case. Furthermore, although the lower connecting pipe has a first bend and a second bend, the portion of the lower connecting pipe from its upper end to the first bend extends downward along the axis of the case, the portion of the lower connecting pipe from the first bend to the second bend extends downward while inclined relative to the axis of the case, and the portion of the lower connecting pipe from the second bend to its lower end extends downward while inclined relative to the axis of the case. Therefore, when viewed as a whole, the lower connecting pipe extends vertically between the case and the downstream portion of the drain passage. In this way, the cooling water flow path in the collector interposed between the upstream portion of the drain passage and the downstream portion of the drain passage is not significantly bent like the flow path of the prior art shown in Figure 9(B). Therefore, an increase in pressure loss in the flow path of the cooling water in the collector can be suppressed, and the flow of the cooling water in the collector can be improved.

[0018] In addition, in the collector of the cooling device of this embodiment, the lower connecting pipe is provided with a first bent portion and a second bent portion, and the portion of the lower connecting pipe from the first bent portion to the second bent portion and the portion of the lower connecting pipe from the second bent portion to the lower end are inclined with respect to the axis of the case, which extends in the vertical direction. Therefore, a user can easily bend the lower connecting pipe and move the upper end portion of the lower connecting pipe downward by grasping the upper portion of the lower connecting pipe with their hand and applying a downward force. For example, by configuring the case so that it can be removed from the upper and lower connecting pipes by moving the upper end portion of the lower connecting pipe downward, or by configuring the case so that it can be separated from the case by moving the upper end portion of the lower connecting pipe downward, a user can easily perform maintenance on the collector body housed in the case (e.g., remove fine objects accumulated in the collector body). [Example]

[0019] Hereinafter, an embodiment of a cooling device for a marine propulsion unit of the present invention will be described with reference to Figures 1 to 8. In the embodiments, when directions such as front (Fd), rear (Bd), top (Ud), bottom (Dd), left (Ld), and right (Rd) are described, they will be referred to by the arrows drawn at the bottom left of Figures 1 to 8.

[0020] (Outboard motor) FIG. 1 shows an outboard motor 1, one type of marine propulsion device, as viewed from the left. As shown in FIG. 1, the outboard motor 1 includes an engine 2 as a power source, a drive shaft 3 that rotates with power from the engine 2, a propeller 4 that generates propulsive force for the marine vessel, a propeller shaft 5 to which the propeller 4 is attached, and a gear mechanism 6 that transmits the rotation of the drive shaft 3 to the propeller shaft 5. Although not shown, the gear mechanism 6 is also provided with a shift device that switches the direction of rotation transmitted from the drive shaft 3 to the propeller shaft 5. The engine 2 is located at the top of the outboard motor 1. The gear mechanism 6, the propeller shaft 5, and the propeller 4 are located at the bottom of the outboard motor 1. The drive shaft 3 extends vertically between the engine 2 and the gear mechanism 6.

[0021] The lower part of the engine 2 is covered by an engine bottom cover 7, and the vertical middle and upper parts of the engine 2 are covered by an engine top cover 8. The engine top cover 8 is detachably attached to the engine bottom cover 7. By removing the engine top cover 8, a wide range of the engine 2 from the vertical middle to the upper part can be exposed. The upper part of the drive shaft 3 is covered by an upper case 9, and the vertical middle part of the drive shaft 3 is covered by a middle case 10. The lower part of the drive shaft 3 and the front part of the gear mechanism 6 and propeller shaft 5 are covered by a lower case 11.

[0022] FIG. 2 shows the engine 2 as seen from the left. FIG. 3 shows the engine 2 as seen from the rear. The engine 2 is, for example, a four-stroke, four-cylinder gasoline engine, and is cooled by water. The engine 2 is arranged so that the extension direction of the crankshaft is the vertical direction. As shown in FIG. 2, the engine 2 has a crankcase 12 arranged at the front, a cylinder block 13 arranged behind the crankcase 12, and a cylinder head 14 arranged behind the cylinder block 13. The rear of the cylinder head 14 is covered by a cylinder head cover 15.

[0023] As shown in FIG. 1 , the outboard motor 1 is provided with an exhaust passage 16 for discharging exhaust gas emitted from the engine 2 outside the outboard motor 1. The upper end of the exhaust passage 16 is connected to an exhaust port provided in the cylinder head 14 of the engine 2, and the lower end of the exhaust passage 16 is connected to an exhaust chamber 17 provided in the rear lower part of the outboard motor 1. In the outboard motor 1 of this embodiment, the exhaust chamber 17 is provided in a section extending from the rear of the middle case 10 to the rear of the lower case 11. Exhaust gas discharged from an exhaust port of the engine 2 is sent to the exhaust chamber 17 via the exhaust passage 16, and then discharged outside the outboard motor 1 through an outlet provided in, for example, the shaft of the propeller 4. Note that the exhaust port of the engine 2 and the exhaust passage 16 are not shown in FIGS. 2 and 3 .

[0024] (cooling device) The outboard motor 1 is equipped with a cooling device 21 that uses the water around the outboard motor 1, such as seawater, lake water, or river water, as cooling water to cool the engine 2 and other heat-generating parts of the outboard motor 1. Figure 4 shows the configuration of the cooling device 21.

[0025] As shown in FIG. 4, the cooling device 21 includes a water intake port 22, a water intake passage 23, a water pump 24, a water supply passage 25, a water jacket 26, a water drain passage 27, a thermostat 28, a pressure valve 29, and a collector 31.

[0026] The water intake 22 is an opening for taking in water around the outboard motor 1 into the outboard motor 1, and is provided in a portion of the outboard motor 1 that is submerged underwater, specifically in a part of the lower case 11 (see FIG. 1). The water intake 22 is also provided with a strainer or a cover with many small holes to prevent stones, algae, and other objects larger than minute particles from entering the outboard motor 1 along with seawater, lake water, or river water.

[0027] The water intake passage 23 is a passage for sucking water taken into the outboard motor 1 through the water intake port 22 into the water pump 24, and is provided inside the lower case 11.

[0028] The water pump 24 is a pump that sucks water taken into the outboard motor 1 through the water intake 22 and discharges the sucked water as cooling water, and is provided, for example, inside the lower case 11 or the middle case 10. The water pump 24 is operated using the rotation of the drive shaft 3.

[0029] The water supply passage 25 is a passage for supplying the cooling water discharged from the water pump 24 to the water jacket 26, and is formed, for example, by hoses or pipes provided inside the middle case 10, upper case 9, and engine bottom cover 7.

[0030] The water jacket 26 is a mechanism for cooling the engine 2 by causing the cooling water fed through the water supply passage 25 to flow around or inside the engine 2, and is provided around or inside the engine 2.

[0031] The drain passage 27 is a passage for discharging the cooling water that has flowed through the water jacket 26 to the outside of the outboard motor 1, and is formed, for example, by a hose or a pipe provided inside the engine top cover 8, the engine bottom cover 7, the upper case 9, etc. As shown in FIG. 2, the upstream end of the drain passage 27 is connected to the outlet 26A of the water jacket 26 that is located on top of the cylinder head 14. The drain passage 27 extends from the outlet 26A of the water jacket 26 to the upper left side of the rear of the engine 2, passes through a collector 31, and then extends downward inside the engine bottom cover 7 and the upper case 9. The downstream end of the drain passage 27 is connected to the exhaust chamber 17 as shown in FIG. 4.

[0032] The thermostat 28 is a device that limits the flow of coolant to warm up the engine 2 or to prevent the engine 2 from overcooling, and is provided, for example, near the outlet 26A of the water jacket 26. The thermostat 28 opens when the temperature of the coolant flowing through the water jacket 26 reaches or exceeds a predetermined reference temperature, and closes when the temperature of the coolant falls below the reference temperature.

[0033] Pressure valve 29 is a valve that reduces the water pressure in water supply passage 25 or water jacket 26 by allowing the water coolant discharged from water pump 24 to escape toward exhaust chamber 17 when the flow of water coolant is restricted by thermostat 28. Pressure valve 29 is, for example, a normally closed valve, and opens when the water pressure in water supply passage 25 exceeds a predetermined reference pressure.

[0034] The collector 31 is a device that collects fine particles contained in the cooling water flowing through the drain passage 27. The collector 31 will be described in detail later.

[0035] In the cooling system 21 configured as described above, when the water pump 24 is operating, the thermostat 28 is open, and the pressure valve 29 is closed, water around the outboard motor 1 is taken into the outboard motor 1 through the water intake 22, flows sequentially through the water intake passage 23 and the water supply passage 25, and is sent to the water jacket 26 as cooling water. The cooling water sent to the water jacket 26 flows within the water jacket 26, thereby cooling the engine 2. The cooling water that has flowed within the water jacket 26 flows from the outlet 26A of the water jacket 26 into the drain passage 27, flows through the drain passage 27, passes through the collector 31, and is then discharged into the exhaust chamber 17. The cooling water discharged into the exhaust chamber 17 is discharged together with exhaust gases to the outside of the outboard motor 1, for example, through an outlet provided on the shaft of the propeller 4. On the other hand, when the water pump 24 is operating, the thermostat 28 is closed, and the pressure valve 29 is open, water taken into the outboard motor 1 from the water intake 22 flows sequentially through the water intake passage 23 and the water supply passage 25, but before reaching the water jacket 26, it is sent to the exhaust chamber 17 side via the open pressure valve 29 and released into the exhaust chamber 17. The cooling water released into the exhaust chamber 17 is discharged outside the outboard motor 1 together with the exhaust gas.

[0036] (collector) As described above, the collector 31 is a device that collects fine particles contained in the cooling water flowing through the drain passage 27. The fine particles include, for example, microplastics and other small debris, or residue from aquaculture feed. The size of the fine particles is, for example, approximately 0.1 mm or more and approximately 5 mm or less. Because of their size, the fine particles cannot be removed by a strainer or a cover with many small holes attached to the water intake 22. Specifically, when the water pump 24 is operating, the thermostat 28 is open, and the pressure valve 29 is closed, the fine particles enter the outboard motor 1 through the water intake 22 along with seawater, lake water, or river water, and then flow into the collector 31 through the water intake passage 23, the water supply passage 25, the water jacket 26, and the upstream portion 27A of the drain passage 27.

[0037] 2 and 3, the collector 31 is disposed on the left side of the rear of the engine 2. The collector 31 is disposed between the upstream portion 27A and the downstream portion 27B of the drain passage 27. The collector 31 is disposed inside the engine top cover 8 together with a bypass passage 56, which will be described later.

[0038] The upstream portion 27A of the drain passage 27 is a portion of the drain passage 27 that is located in a region from above the middle portion of the engine 2 in the front-rear direction and the middle portion in the left-right direction to the left of the upper rear portion of the engine 2. Specifically, the upstream portion 27A of the drain passage 27 is a portion of the drain passage 27 that extends from the outlet 26A of the water jacket 26 located at the top of the cylinder head 14 to a position on the left of the top of the cylinder head cover 15. The upstream portion 27A of the drain passage 27 is formed from a pipe made of resin or metal that is highly heat-resistant and rigid, or a hose made of rubber that is highly corrosion-resistant and rigid, or the like. Furthermore, the upstream portion 27A of the drain passage 27 extends leftward from the outlet 26A of the water jacket 26 and then bends, then extends rearward while sloping downward on the left side of the upper rear portion of the engine 2 and then bends, then extends horizontally rearward on the left side of the upper rear portion of the engine 2 and then bends, and then extends vertically downward on the left side of the upper rear portion of the engine 2. The opening at the lower end of the upstream portion 27A of the drain passage 27 faces downward.

[0039] Further, downstream portion 27B of drain passage 27 is the portion of drain passage 27 that is located in the region from the lower left part of the rear of engine 2 to exhaust chamber 17. The upper end of downstream portion 27B of drain passage 27 is formed by drain hole 30 formed in the lower left part of the rear of the housing of engine 2. Further, the portion of downstream portion 27B of drain passage 27 below the upper end is formed by hoses or pipes provided inside engine bottom cover 7, upper case 9, etc. Further, the upper end of downstream portion 27B of drain passage 27, i.e., drain hole 30, is inclined slightly to the right but extends downward, and the upper opening of drain hole 30 faces upward.

[0040] Figure 5 shows a cross section of the upstream portion 27A of the drainage passage 27, the collector 31, the upper end of the downstream portion 27B of the drainage passage 27, and the bypass passage 56 taken along the cutting line VV in Figure 3, viewed from the left. As shown in Figure 5, the collector 31 has a filter cartridge 32, a case 41, a branch pipe 53, a connecting hose 54, and a junction pipe 55. Note that the filter cartridge 32 is a specific example of the "collector main body," the branch pipe 53 is a specific example of the "upper connecting pipe," and the connecting hose 54 is a specific example of the "lower connecting pipe."

[0041] FIG. 6 is an enlarged view of the filter cartridge 32 and case 41 in FIG. 5. As shown in FIG. 6, the filter cartridge 32 includes a filter 33 that captures fine particles and allows cooling water to pass through, and a holder 34 that holds the filter 33. The filter 33 is formed, for example, from a nonwoven fabric or a resin mesh, and is shaped like a bag with an open top and a closed bottom. The holder 34 is formed, for example, from a heat-resistant and highly rigid resin or a highly corrosion-resistant metal, into a cylindrical shape with an axis extending in the vertical direction. The peripheral wall of the holder 34 is provided with multiple water passage holes 37. The filter 33 is disposed inside the holder 34 so as to cover each water passage hole 37 and the lower opening 36 of the holder 34. The upper part of the filter 33 is attached and fixed to the inner peripheral surface of the upper part of the holder 34, for example, with an adhesive.

[0042] An O-ring 38 is provided in an annular recess formed on the outer peripheral surface of the upper part of holder 34. O-ring 38 presses against and contacts the inner surface of upper case portion 42. O-ring 38 functions to prevent holder 34 from easily falling off upper case portion 42 when lower case portion 45 is separated from upper case portion 42.

[0043] The case 41 is a component that houses the filter cartridge 32. The case 41 is formed into a cylindrical shape having an axis that extends in the vertical direction and is made of a heat-resistant and highly rigid resin, a highly corrosion-resistant metal, or the like. The case 41 is divided into an upper case portion 42 that forms the upper part of the case 41 and a lower case portion 45 that forms the lower part of the case 41.

[0044] The lower end of the first outlet pipe section 53B of the branch pipe 53 is connected to the upper opening 43 of the upper case section 42. In this embodiment, the upper case section 42 is integrally formed with the first outlet pipe section 53B of the branch pipe 53. In addition, a large diameter section 44 having an outer diameter and an inner diameter larger than those of the upper section of the upper case section 42 is formed in the lower section of the upper case section 42, and a thread is formed on the outer peripheral surface of the large diameter section 44.

[0045] Meanwhile, a connecting pipe 46 is provided below the lower case 45, and the lower case 45 and the connecting pipe 46 are integrated. The upper end of the connecting pipe 46 is connected to the upper end of the connecting hose 54. A flange 47 having an outer diameter larger than the outer diameter of the lower part of the lower case 45 is formed at the upper part of the lower case 45, and the flange 47 is inserted into the large diameter part 44 of the upper case 42.

[0046] The lower case portion 45 is detachably connected to the upper case portion 42 by a connecting member 51. That is, the connecting member 51 that detachably connects the lower case portion 45 to the upper case portion 42 is provided on the outer periphery of the lower case portion 45. The connecting member 51 is formed into a cylindrical shape, for example, from resin or metal. The inner diameter of the upper portion of the connecting member 51 is approximately equal to the outer diameter of the large-diameter portion 44 of the upper case portion 42, and the inner surface of the upper portion of the connecting member 51 is formed with threads that mesh with the threads formed on the large-diameter portion 44 of the upper case portion 42. The inner diameter of the lower portion of the connecting member 51 is smaller than the outer diameter of the flange portion 47 of the lower case portion 45 and larger than the outer diameter of the lower portion of the lower case portion 45. The connecting member 51 can rotate around the lower case portion 45. The lower case portion 45 can be connected and fixed to the upper case portion 42 by screwing the connecting member 51 into the large-diameter portion 44 of the upper case portion 42. Furthermore, by removing the connecting member 51 from the large diameter portion 44 of the upper case portion 42, the lower case portion 45 can be separated from the upper case portion 42. Furthermore, a protrusion 48 is formed on the outer circumferential surface of the lower end portion of the lower case portion 45 to prevent the connecting member 51 from falling off the lower case portion 45 when the connecting member 51 is removed from the large diameter portion 44 of the upper case portion 42.

[0047] In addition, an O-ring 50 is provided on the upper surface of the lower case portion 45 to seal between the upper case portion 42 and the lower case portion 45 when the lower case portion 45 is joined to the upper case portion 42.

[0048] The upper part of filter cartridge 32 is mounted in upper case portion 42, and is prevented from slipping out of upper case portion 42 by O-ring 38 provided on the upper part of holder 34. When lower case portion 45 is joined to upper case portion 42, the lower part of filter cartridge 32 is covered by lower case portion 45, and filter cartridge 32 is held between upper case portion 42 and lower case portion 45. Filter cartridge 32 is arranged coaxially with case 41, and the position of upper opening 35 of holder 34 of filter cartridge 32 coincides with the position of upper opening 43 of upper case portion 42, and the position of lower opening 36 of holder 34 coincides with the position of lower opening 49 of lower case portion 45.

[0049] 6 indicates the vertical position of the upper end of the lower case portion 45 when the lower case portion 45 is joined to the upper case portion 42. Further, the double-dashed line Q in Fig. 6 indicates the vertical center position of the filter cartridge 32 when the filter cartridge 32 is held between the joined upper case portion 42 and lower case portion 45. As can be seen from the double-dashed lines P and Q, when the lower case portion 45 is joined to the upper case portion 42 and the filter cartridge 32 is held between the upper case portion 42 and the lower case portion 45, the upper end of the lower case portion 45 is located below the vertical center of the filter cartridge 32.

[0050] The cooling water flows from first outlet pipe portion 53B of branch pipe 53, sequentially through upper opening 43 of upper case portion 42 and upper opening 35 of holder 34, and into bag-shaped filter 33 disposed in holder 34 of filter cartridge 32. The cooling water that has flowed into filter 33 passes through filter 33, passes sequentially through lower opening 36 of holder 34, lower opening 49 of lower case portion 45, and connecting pipe portion 46, and then flows into connecting hose 54. As the cooling water passes through filter 33, fine particles in the cooling water are captured by filter 33 and removed from the cooling water.

[0051] 5, branch pipe 53 is a pipe that connects upstream portion 27A of drain passage 27 to case 41 and also connects upstream portion 27A of drain passage 27 to bypass passage 56. Branch pipe 53 is made of a resin that is highly heat-resistant and rigid, or a metal that is highly corrosion-resistant, etc. Branch pipe 53 has an inlet pipe portion 53A, a first outlet pipe portion 53B, and a second outlet pipe portion 53C.

[0052] In the branch pipe 53, the inflow pipe section 53A is located at the upper side, and the first outflow pipe section 53B is located at the lower side. The inflow pipe section 53A and the first outflow pipe section 53B are arranged coaxially, and the portion of the branch pipe 53 from the inflow pipe section 53A to the first outflow pipe section 53B extends linearly in the vertical direction. The upper end of the inflow pipe section 53A is connected to the lower end of the upstream section 27A of the drainage passage 27, and the lower end of the first outflow pipe section 53B is connected to the upper opening 43 of the upper case section 42 (in this embodiment, as described above, the first outflow pipe section 53B and the upper case section 42 are integrally formed). The inflow pipe section 53A is arranged coaxially with the lower end of the upstream section 27A of the drainage passage 27, and the first outflow pipe section 53B is arranged coaxially with the case 41.

[0053] The second outlet pipe section 53C extends forward while sloping downward from approximately the middle in the vertical direction of the portion of the branch pipe 53 between the inlet pipe section 53A and the first outlet pipe section 53B. The upper end of a bypass pipe 57 that forms the upper part of the bypass passage 56 is connected to the lower end of the second outlet pipe section 53C.

[0054] The connection hose 54 is a pipe that connects the case 41 and the first inlet pipe portion 55A of the junction pipe 55. The connection hose 54 is made of a rubber hose that is heat resistant and highly rigid. For example, 3In the case of an outboard motor 1 equipped with an engine 2 with a maximum output of approximately 103 kW (140 PS), a connecting hose 54 is a reinforced fiber rubber hose having an outer diameter of 34 mm, a hose thickness of 3.5 mm, and a rubber hardness of 65 to 75 (durometer A hardness). The connecting hose 54 is flexible but has high rigidity, making it difficult to bend. The upper end of the connecting hose 54 is connected to the lower end of the connecting pipe portion 46 formed integrally with the lower case portion 45. The lower end of the connecting hose 54 is connected to the upper end of the first inlet pipe portion 55A of the junction pipe 55. The upper end of the connecting hose 54 is arranged coaxially with the case 41.

[0055] Furthermore, connection hose 54 has upper bent portion 54A between its upper end and lower end, and lower bent portion 54B between upper bent portion 54A and its lower end. As will be described in detail later, upper bent portion 54A and lower bent portion 54B function to make connection hose 54 more flexible when lower case portion 45 is moved downward to separate it from upper case portion 42. In this embodiment, lower bent portion 54B is located approximately in the center between the upper end and lower end of connection hose 54, and upper bent portion 54A is located approximately in the center between the upper end of connection hose 54 and lower bent portion 54B.

[0056] Connection hose 54 extends downward from its upper end along axis J of case 41, then bends at upper bent portion 54A, then extends downward while inclining with respect to axis J so as to move away from axis J, then bends at lower bent portion 54B, and then extends downward while inclining with respect to axis J so as to move closer to axis J. Furthermore, the portion of connection hose 54 from upper bent portion 54A to lower bent portion 54B extends downward while inclining toward the rear of engine 2 and the center (right) of engine 2 in the left-right direction, as shown in FIGS. 2 and 3 . Furthermore, the portion of connection hose 54 from lower bent portion 54B to the lower end extends downward while inclining toward the front left.

[0057] Although the connection hose 54 has an upper bent portion 54A and a lower bent portion 54B as described above, the portion from the upper end of the connection hose 54 to the upper bent portion 54A extends downward along the axis J of the case 41, the portion from the upper bent portion 54A to the lower bent portion 54B of the connection hose 54 extends downward although it is inclined with respect to the axis J, and the portion from the lower bent portion 54B to the lower end of the connection hose 54 extends downward although it is inclined with respect to the axis J. Therefore, when viewed as a whole, the connection hose 54 extends in the vertical direction between the case 41 and the junction pipe 55. The upper bent portion 54A is a specific example of a "first bent portion," and the lower bent portion 54B is a specific example of a "second bent portion."

[0058] Junction pipe 55 is a pipe that connects connection hose 54 and downstream portion 27B of drain passage 27, and also connects bypass passage 56 and downstream portion 27B of drain passage 27. Junction pipe 55 is made of a resin that is highly heat-resistant and rigid, or a metal that is highly corrosion-resistant, etc. Junction pipe 55 has a first inlet pipe portion 55A, a second inlet pipe portion 55B, and an outlet pipe portion 55C.

[0059] In the junction pipe 55, the second inlet pipe section 55B is located on the upper side, and the outlet pipe section 55C is located on the lower side. The second inlet pipe section 55B and the outlet pipe section 55C are arranged coaxially, and the portion of the junction pipe 55 from the second inlet pipe section 55B to the outlet pipe section 55C extends linearly in the vertical direction. The upper end of the second inlet pipe section 55B is connected to the lower end of a connecting pipe 58 that forms the lower part of the bypass passage 56, and the lower end of the outlet pipe section 55C is connected to the upper end of the downstream section 27B (drain hole 30) of the drain passage 27.

[0060] The first inlet pipe 55A extends rearward while sloping upward and to the right from approximately the middle in the vertical direction of the portion of the junction pipe 55 between the second inlet pipe 55B and the outlet pipe 55C. The lower end of the connection hose 54 is connected to the upper end of the first inlet pipe 55A. The inner diameters of the inlet pipe 53A of the branch pipe 53, the first outlet pipe 53B of the branch pipe 53, the connection hose 54, and the first inlet pipe 55A of the junction pipe 55 are all approximately the same.

[0061] (Bypass passage) In the cooling device 21, a bypass passage 56 is provided between the upstream portion 27A and the downstream portion 27B of the drain passage 27. The bypass passage 56 is connected in parallel to the passage formed by the filter cartridge 32, the case 41, and the connecting hose 54 between the upstream portion 27A and the downstream portion 27B of the drain passage 27. The bypass passage 56 is a passage for smoothly flowing cooling water from the upstream portion 27A to the downstream portion 27B of the drain passage 27 when, for example, a large amount of fine particles accumulate in the filter 33 and the filter 33 becomes clogged. In other words, when the filter 33 becomes clogged, it becomes difficult for the cooling water to pass through the filter 33. Therefore, it becomes difficult for the cooling water flowing out from the upstream portion 27A of the drain passage 27 to flow through the passage formed by the filter cartridge 32, the case 41, and the connecting hose 54. In this case, the cooling water flowing out from the upstream portion 27A of the drain passage 27 flows through the bypass passage 56.

[0062] The bypass passage 56 is formed by a bypass pipe 57 and a connecting pipe 58. The bypass pipe 57 is formed of a heat-resistant and highly rigid rubber hose, or a heat-resistant and highly rigid resin or corrosion-resistant metal pipe. The upper end of the bypass pipe 57 is connected to the lower end of the second outlet pipe portion 53C of the branch pipe 53, and the lower end of the bypass pipe 57 is connected to the upper end of the connecting pipe 58. The bypass pipe 57 extends downward from its upper end while tilting forward with respect to the axis J of the case 41, then bends, and then extends in the vertical direction so as to be parallel to the axis J of the case 41. The connecting pipe 58 is formed of a heat-resistant and highly rigid resin or a highly corrosion-resistant metal. The lower end of the connecting pipe 58 is connected to the upper end of the second inlet pipe portion 55B of the junction pipe 55. The connecting pipe 58 extends in the vertical direction and is arranged coaxially with the bypass pipe 57. The inner diameters of the second outlet pipe section 53C of the branch pipe 53, the bypass pipe 57, the connecting pipe 58, and the second inlet pipe section 55B of the junction pipe 55 are all approximately equal. The inner diameters of the second outlet pipe section 53C of the branch pipe 53, the bypass pipe 57, the connecting pipe 58, and the second inlet pipe section 55B of the junction pipe 55 are also approximately equal to the inner diameters of the inlet pipe section 53A of the branch pipe 53, the first outlet pipe section 53B of the branch pipe 53, the connecting hose 54, and the first inlet pipe section 55A of the junction pipe 55.

[0063] (Flow of cooling water in the collector and bypass passage) In FIG. 5 , cooling water flows from upstream portion 27A of drain passage 27 into inlet pipe portion 53A of branch pipe 53, as indicated by arrow A. Inlet pipe portion 53A of branch pipe 53, first outlet pipe portion 53B of branch pipe 53, and case 41 are all coaxially arranged, and the flow path from inlet pipe portion 53A of branch pipe 53 to case 41 extends linearly in the vertical direction. In contrast, second outlet pipe portion 53C of branch pipe 53 is inclined relative to inlet pipe portion 53A of branch pipe 53, and the flow path from inlet pipe portion 53A of branch pipe 53 to bypass pipe 57 is curved. Therefore, when filter 33 is not clogged, most of the cooling water that flows into inlet pipe portion 53A of branch pipe 53 flows into case 41 through first outlet pipe portion 53B of branch pipe 53, as indicated by arrow B. The cooling water that has flowed into case 41 passes through filter 33, flows out of case 41, and flows into connecting hose 54. As the cooling water passes through filter 33, fine particles in the cooling water are removed. The cooling water that has flowed into connecting hose 54 flows through connecting hose 54 and, as indicated by arrow C, flows into first inlet pipe section 55A of junction pipe 55, and then, as indicated by arrow D, flows from outlet pipe section 55C of junction pipe 55 into downstream section 27B of drainage passage 27.

[0064] Furthermore, there are no large bends in the flow path from upstream portion 27A of drain passage 27 through inlet pipe portion 53A of branch pipe 53, first outlet pipe portion 53B of branch pipe 53, case 41, connecting hose 54, first inlet pipe portion 55A of junction pipe 55, and outlet pipe portion 55C of junction pipe 55 to downstream portion 27B of drain passage 27. Therefore, when filter 33 is not clogged, cooling water flows smoothly from upstream portion 27A of drain passage 27 through inlet pipe portion 53A of branch pipe 53, first outlet pipe portion 53B of branch pipe 53, case 41, connecting hose 54, first inlet pipe portion 55A of junction pipe 55, and outlet pipe portion 55C of junction pipe 55 to downstream portion 27B of drain passage 27.

[0065] On the other hand, if filter 33 is clogged or the like, it becomes difficult for the cooling water to pass through filter 33, and the flow of cooling water is stagnated in case 41 and first outlet pipe portion 53B of branch pipe 53. Therefore, if filter 33 is clogged or the like, most of the cooling water that flows from upstream portion 27A of drain passage 27 into inlet pipe portion 53A of branch pipe 53 flows into bypass pipe 57 through second outlet pipe portion 53C of branch pipe 53, as indicated by arrow E. The cooling water that flows into bypass pipe 57 passes sequentially through bypass pipe 57 and connecting pipe 58, as indicated by arrow F, into second inlet pipe portion 55B of junction pipe 55, and then flows from outlet pipe portion 55C of junction pipe 55 into downstream portion 27B of drain passage 27, as indicated by arrow D.

[0066] (Removing and attaching the lower case) When the outboard motor 1 is used to sail the boat, fine matter is captured by the filter 33 of the collector 31 and accumulates in the filter 33. Therefore, after using the outboard motor 1, the user removes the fine matter accumulated in the filter 33. Furthermore, after using the outboard motor 1 for an extended period of time, the user replaces the filter cartridge 32. When performing such maintenance on the collector 31, the user separates the lower case portion 45 from the upper case portion 42 and removes the filter cartridge 32 from the upper case portion 42.

[0067] FIG. 7 shows a method for separating the lower case portion 45 from the upper case portion 42 and removing the filter cartridge 32 from the upper case portion 42. First, the user rotates the connecting member 51 of the case 41 in the direction that unscrews it, thereby removing the connecting member 51 from the large-diameter portion 44 of the upper case portion 42. Next, as shown in FIG. 7(A), the user grasps the upper portion of the connection hose 54 with their hand and pushes it down as indicated by arrow K in FIG. 7(A). By pushing down the upper portion of the connection hose 54, the lower case portion 45 moves downward, and as shown in FIG. 7(B), the lower case portion 45 separates from the upper case portion 42. Next, the user pushes the upper portion of the connection hose 54 in the direction away from the engine 2 (generally to the left) as indicated by arrow L in FIG. 7(B), thereby moving the lower case portion 45 to a position away from directly below the upper case portion 42. As shown in Figure 7(C), after moving the lower case part 45 to a position away from directly below the upper case part 42, the user pulls down the filter cartridge 32 attached to the upper case part 42 as indicated by the arrow M in Figure 7(C) to remove it from the upper case part 42.

[0068] Thereafter, the user removes the fine matter accumulated in the filter 33, and mounts the filter cartridge 32 from which the fine matter has been removed into the upper case part 42, or mounts a new filter cartridge 32 into the upper case part 42, and then attaches the lower case part 45 to the upper case part 42 to join the two together.

[0069] As described above, the connection hose 54 is flexible but has high rigidity and is therefore difficult to bend. However, in the outboard motor 1 of this embodiment, the user can grasp the upper part of the connection hose 54 with their hand and push down, as shown in Figure 7, to separate the lower case part 45 from the upper case part 42. This point will be explained below.

[0070] If the connecting hose were to extend vertically in a straight line from case 41 to first inlet pipe section 55A of junction pipe 55, even if a user grasped the upper part of the connecting hose with their hand and applied downward force, it would be difficult to push down the connecting hose, and it would be difficult to separate lower case section 45 from upper case section 42. One reason for this is that the direction of the force applied to the connecting hose is the same as the direction in which the connecting hose extends, making it extremely difficult for the connecting hose to bend.

[0071] However, in the outboard motor 1 of this embodiment, the connection hose 54 is provided with an upper bent portion 54A and a lower bent portion 54B, and the portion of the connection hose 54 from the upper bent portion 54A to the lower bent portion 54B and the portion of the connection hose 54 from the lower bent portion 54B to the lower end thereof extend in a direction intersecting with the axis J of the case 41, which extends in the vertical direction. Therefore, when a user grips the upper portion of the connection hose 54 with their hand and applies a downward force, the direction of the force differs from the direction in which the portion of the connection hose 54 from the upper bent portion 54A to the lower bent portion 54B extends, and also differs from the direction in which the portion of the connection hose 54 from the lower bent portion 54B to the lower end thereof extends. Therefore, the connection hose 54 is more flexible than when the connection hose 54 extends linearly in the vertical direction, as described above. Therefore, by grasping the upper part of the connection hose 54 with one hand and applying downward force, the user can easily push down the connection hose 54, and easily separate the lower case part 45 from the upper case part 42.

[0072] (Positional relationship between connection hose and bypass hose) Figure 8 shows a cross section of connection hose 54 and bypass pipe 57 taken along section line VIII-VIII in Figure 5, viewed from above. When connection hose 54 and bypass pipe 57 are viewed from above as shown in Figure 8, axis N of the portion of connection hose 54 from upper bent portion 54A to lower bent portion 54B intersects with straight line T, which passes through both axis U of the upper end of connection hose 54 and axis V of bypass pipe 57 excluding its inclined upper end portion.

[0073] Because the connection hose 54 and the bypass pipe 57 are arranged in this manner, the lower bent portion 54B of the connection hose 54 and the like do not come into contact with the bypass pipe 57. Furthermore, when the lower case portion 45 is separated from the upper case portion 42 and the filter cartridge 32 is removed from the upper case portion 42, as shown by the two-dot chain line in Figure 8, the lower case portion 45 separated from the upper case portion 42 does not come into contact with the bypass pipe 57. Note that the two-dot chain line in Figure 8 shows the lower case portion 45 in a state where it has been pushed and moved to the position shown in Figure 7(C).

[0074] As described above, in the collector 31 of the cooling device 21 of the embodiment of the present invention, the case 41 that houses the filter cartridge 32 is formed in a cylindrical shape with an axis that extends vertically. The upstream portion 27A of the drain passage 27 and the case 41 are connected by the inlet pipe portion 53A and the first outlet pipe portion 53B of the branch pipe 53 that extends vertically. The case 41 and the downstream portion 27B of the drain passage 27 are connected by the connecting hose 54 that has bent portions 54A and 54B but extends vertically overall. In this way, the cooling water flow path in the collector 31 between the upstream portion 27A of the drain passage 27 and the downstream portion 27B of the drain passage 27 is not significantly bent like the flow path in the prior art shown in FIG. 9(B). Therefore, an increase in pressure loss in the cooling water flow path in the collector 31 can be suppressed, and the flow of cooling water in the collector 31 can be improved.

[0075] Furthermore, in collector 31 of cooling device 21 of this embodiment, connection hose 54 is provided with upper bent portion 54A and lower bent portion 54B, and the portion of connection hose 54 from upper bent portion 54A to lower bent portion 54B and the portion of connection hose 54 from lower bent portion 54B to its lower end are inclined with respect to axis J of case 41, which extends in the vertical direction. Therefore, a user can easily bend connection hose 54 by grasping the upper portion of connection hose 54 with their hand and applying a downward force, thereby moving lower case portion 45 connected to the upper end of connection hose 54 downward and easily separating lower case portion 45 from upper case portion 42. This allows the user to easily perform maintenance on collector 31.

[0076] Furthermore, the portion of the connection hose 54 from the upper bent portion 54A to the lower bent portion 54B extends downward while sloping toward the rear of the engine 2 and toward the center in the left-right direction of the engine 2. This prevents a portion of the connection hose 54, such as the lower bent portion 54B, from protruding outward to the side of the engine 2. This allows the engine top cover 8, which covers the engine 2 in which the collector 31 is disposed, to be made smaller, thereby enabling the outboard motor 1 to be made more compact.

[0077] Furthermore, when the lower case portion 45 is coupled to the upper case portion 42, the upper end of the lower case portion 45 is located below the center of the filter cartridge 32 in the up-down direction. This reduces the amount of downward movement of the lower case portion 45 when separating the lower case portion 45 from the upper case portion 42. This makes it even easier to separate the lower case portion 45 from the upper case portion 42 and remove the filter cartridge 32 from the upper case portion 42.

[0078] 8 , when the connection hose 54 and the bypass pipe 57 are viewed from above, the axis N of the portion of the connection hose 54 from the upper bent portion 54A to the lower bent portion 54B intersects with a straight line T that passes through both the axis U of the upper end of the connection hose 54 and the axis V of the portion of the bypass pipe 57 excluding the inclined upper end portion. This configuration prevents the lower bent portion 54B and other portions of the connection hose 54 from coming into contact with the bypass pipe 57. Furthermore, when the lower case portion 45 is separated from the upper case portion 42 to remove the filter cartridge 32 from the upper case portion 42, the lower case portion 45 separated from the upper case portion 42 can be prevented from coming into contact with the bypass pipe 57.

[0079] Furthermore, by providing the outboard motor 1 with a cooling device 21 having a collector 31 capable of capturing microplastics, it is possible to collect microplastics that have dispersed in seawater, lake water, river water, etc. while the ship is sailing, thereby purifying the sea, lake, or river.

[0080] In the above embodiment, the filter cartridge 32 is made removable from the case 41 by moving downward the upper end of the connecting hose 54 and the lower case 41, which is inseparably connected to the upper end of the connecting hose 54, together, as an example. However, the present invention is not limited to this. For example, the case 41 may be separably connected to the branch pipe 53 and the case 41 may be separably connected to the connecting hose 54, and the case 41 may be separably connected to the branch pipe 53 and the connecting hose 54, and the case 41 may be separated from both the branch pipe 53 and the connecting hose 54 by pushing down only the upper end of the connecting hose 54. This allows the entire case 41 to be removed from the outboard motor 1, allowing for the removal of fine particles accumulated in the filter 33, etc.

[0081] Furthermore, in the above embodiment, the collector 31 is disposed on the rear left side of the engine 2, but the collector 31 may be disposed at another position around the engine 2, such as on the rear right side of the engine 2.

[0082] The power source of the outboard motor 1 is not limited to an engine, but may be an electric motor. The cooling device of the present invention is not limited to outboard motors, and may also be installed in other types of marine propulsion motors, such as inboard-outboard motors or inboard motors.

[0083] Furthermore, the present invention can be modified as appropriate within the scope that does not contradict the gist or concept of the invention that can be read from the claims and the entire specification, and cooling devices for marine propulsion units that involve such modifications are also included in the technical concept of the present invention. [Explanation of symbols]

[0084] 1. Outboard motor (marine propulsion unit) 2 Engine (power source) 21 Cooling device 27 Drain passage 27A Upstream section 27B Downstream 31 Collector 32 Filter cartridge (collector body) 41 cases 42 Upper case part 45 Lower case part 53 Branch pipe (upper connecting pipe) 54 Connecting hose (lower connecting pipe) 54A Upper bend (first bend) 54B Lower bend (second bend) 56 Bypass Passage

Claims

1. A cooling device for a marine propulsion device that is provided to a marine propulsion device, takes in water outside the marine propulsion device into the marine propulsion device, flows the taken-in water around or inside a power source of the marine propulsion device as cooling water to cool the power source, and discharges the cooling water after flowing around or inside the power source to the outside of the marine propulsion device, a drainage passage for discharging the cooling water after flowing around or inside the power source to the outside of the marine propulsion device; a collector interposed between the upstream portion and the downstream portion of the drainage passage and configured to collect fine particles contained in the cooling water flowing from the upstream portion of the drainage passage toward the downstream portion of the drainage passage; a bypass passage, The collector is a collector body that captures the fine objects and allows cooling water to pass through; a case that can be separated into an upper portion and a lower portion and that houses the collector body; an upper connecting pipe that extends vertically, has an upper end connected to the upstream portion of the drain passage, and a lower end connected to an upper portion of the case, and allows cooling water to flow from the upstream portion of the drain passage into the case; a flexible lower connecting pipe having an upper end connected to a lower portion of the case and a lower end connected to a downstream portion of the drain passage, for allowing cooling water to flow from the case to the downstream portion of the drain passage; the bypass passage is a passage that bypasses the collector body and the lower connecting pipe, a bent portion is provided in the lower connecting pipe at a portion located between an upper end portion of the lower connecting pipe and a junction portion where the lower connecting pipe and the bypass passage join together, the lower connecting pipe is bent at the bent portion to extend non-linearly in the up-down direction, 10. A cooling device for a marine propulsion unit, wherein the length of the lower connecting pipe is longer than the length of the upper connecting pipe.

2. the bent portion includes a first bent portion provided in a portion of the lower connecting pipe that is located between an upper end of the lower connecting pipe and the junction portion, and a second bent portion provided in a portion of the lower connecting pipe that is located between the first bent portion and the junction portion, a portion of the lower connecting pipe between the first bent portion and the second bent portion extends downward while inclining in a direction away from an axis extending in the up-down direction of the case; 2. The cooling device for a marine propulsion unit according to claim 1, wherein a portion of the lower connecting pipe below the second bent portion extends downward while inclining toward the axis.

3. 3. The cooling device for a marine propulsion unit according to claim 2, wherein the collector is disposed on the rear side of the power source, and the portion of the lower connecting pipe from the first bent portion to the second bent portion extends downward while inclining toward the rear of the power source and toward the center of the power source in the left-right direction.

4. The case is an upper case portion that forms an upper portion of the case and to which a lower end portion of the upper connecting pipe is connected; a lower case portion that forms a lower portion of the case, to which an upper end portion of the lower connection pipe is connected, and that is separably joined to the upper case portion in the vertical direction; 4. A cooling device for a marine propulsion motor according to claim 1, wherein, when the lower case portion is connected to the upper case portion, the upper end of the lower case portion is located lower than the center of the collector body in the vertical direction.

5. The upper connecting pipe is provided with an outflow pipe section that branches off from the upper connecting pipe, extends downward, and is connected to the upper end of the bypass passage; 5. A cooling device for a marine propulsion unit according to claim 1, wherein an uppermost end of the case is located above a lowermost end of the outflow pipe portion.

6. 5. The cooling device for a marine propulsion unit according to claim 4, wherein the upper case portion is integrally formed with the upper connecting pipe.

7. A cooling device for a marine propulsion unit that is provided in a marine propulsion unit, takes in water outside the marine propulsion unit into the marine propulsion unit, cools the power source by causing the taken-in water to flow around or inside the power source of the marine propulsion unit as cooling water, and discharges the cooling water outside the marine propulsion unit after flowing around or inside the power source, a drainage passage for discharging the cooling water after flowing around or inside the power source to the outside of the marine propulsion device; a collector disposed between the upstream and downstream portions of the drainage passage and configured to collect fine particles contained in the cooling water flowing from the upstream portion of the drainage passage toward the downstream portion of the drainage passage; The collector is a collector body that captures the fine objects and allows cooling water to pass through; a case that can be separated into an upper portion and a lower portion and that houses the collector body; an upper connecting pipe that extends vertically, has an upper end connected to the upstream portion of the drain passage, and a lower end connected to an upper portion of the case, and allows cooling water to flow from the upstream portion of the drain passage into the case; a flexible lower connecting pipe having an upper end connected to a lower portion of the case and a lower end connected to a downstream portion of the drain passage, for allowing cooling water to flow from the case to the downstream portion of the drain passage; a bent portion is provided between the upper end and the lower end of the lower connecting pipe, the lower connecting pipe is bent at the bent portion to extend non-linearly in the up-down direction, the length of the lower connecting pipe is longer than the length of the upper connecting pipe; The case is an upper case portion that forms an upper portion of the case and to which a lower end portion of the upper connecting pipe is connected; a lower case portion that forms a lower portion of the case, to which an upper end portion of the lower connection pipe is connected, and that is separably joined to the upper case portion in the vertical direction; A cooling device for a marine propulsion unit, characterized in that when the lower case portion is connected to the upper case portion, the upper end of the lower case portion is located lower than the center of the collector body in the vertical direction.

Images