Fine dust capture device

Abstract

To suppress fine dust accumulated in a filter from separating from the filter and being dispersed when direction of water flowing in the periphery of a fine dust capture device becomes the direction reverse to advancing of a vessel.SOLUTION: A fine dust capture device 21 includes a water inlet 26 provided on a front end side of a body part 22, a rear wall part 27 sealing a rear end side of the main part 22, a first passage 31 and a second passage 32 stretching in the front to back direction in the main part 22, a drain chamber 38 provided in between respective rear end parts and rear wall parts 27 of the first passage 31 and the second passage 32 in the main body 22, an outlet 39 provided on the rear wall part 27, and a filter 40 provided in the first passage 31. Respective rear end sides of the first passage 31 and the second passage 32 open into the drain chamber 38, and the outlet 39 does not face an opening of the first passage 31 opening into the drain chamber 38 but is arranged in a position facing an opening of the second passage 32 opening into the exhaust chamber 38 in the rear wall part 27.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a fine dust capturing device that is provided in a ship propulsion machine and captures fine dust contained in water such as the sea, lakes, rivers, etc. while the ship is sailing. [Background technology]

[0002] In recent years, pollution by fine dust particles such as microplastics has become a problem in seas, lakes, rivers, etc., and there is a demand for collecting such fine dust particles from seas, lakes, rivers, etc., and purifying the seas, lakes, rivers, etc.

[0003] JP 2021-169240 A (Patent Document 1) describes an outboard motor that is capable of collecting fine dust contained in water such as the sea, lakes, and rivers. The outboard motor described in the above publication is provided with a fine dust capture device that captures fine dust. The fine dust capture device has a water intake, a capture device, and an outlet. When a ship is sailing, water from the sea, lake, river, etc. flows into the capture device from the water intake, passes through a filter provided in the capture device, and is then discharged from the outlet into the sea, lake, river, etc. When the water passes through the filter, fine dust contained in the water is captured by the filter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-169240 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to promote the purification of oceans, lakes, rivers, etc., it is desirable to increase the amount of fine dust captured per unit sailing time of a ship or the amount of fine dust captured per unit sailing distance, and to improve the fine dust capture efficiency.

[0006] In the conventional fine dust capture device described in JP 2021-169240 A, the water intake is located in the underwater part at the front of the outboard motor, but the other parts are generally above the water surface, and the drain is located above the water surface and far away from the water surface. Therefore, when the ship is sailing, water from the sea, lake, river, etc. may not flow easily through the fine dust capture device, making it difficult to increase the flow rate of water flowing through the fine dust capture device, and therefore difficult to increase the flow rate of water passing through the filter. As a result, it is difficult to increase the amount of fine dust captured per unit sailing time or the amount of fine dust captured per unit sailing distance, and it is difficult to improve the fine dust capture efficiency.

[0007] Therefore, the inventor of the present application has invented a method of submerging the entire fine dust trapping device in water by arranging the fine dust trapping device in a portion of the outboard motor that is located below the water surface, placing the fine dust trapping device in the water current that flows from the front to the rear of the outboard motor when the boat is moving forward, and efficiently utilizing the water pressure caused by this water current to circulate water through the fine dust trapping device. According to this invention, while the boat is moving forward, the flow rate of water flowing through the fine dust trapping device can be increased compared to the above-mentioned conventional fine dust trapping device, the flow rate of water passing through the filter can be increased, and the efficiency of trapping fine dust can be improved.

[0008] However, the invention raises the following concerns. That is, when a ship reverses or when a ship moving forward suddenly stops, water flows in the opposite direction to when the ship is moving forward. Therefore, water flows backward in the fine dust capture device and passes through the filter in the opposite direction, which may cause the fine dust accumulated in the filter to separate from the filter and diffuse. If the ship reverses or makes a sudden stop frequently while sailing, the frequency of separation and diffusion of the fine dust accumulated in the filter increases, and as a result, there is a risk that the efficiency of capturing the fine dust will not increase.

[0009] The present invention has been made in consideration of problems such as those described above, and its object is to provide a fine dust capture device that can prevent fine dust accumulated in a filter from separating from the filter and diffusing when the direction of water flowing around the fine dust capture device becomes opposite to that when the ship is moving forward. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a fine dust capture device that is provided on a marine propulsion unit and disposed underwater to capture fine dust contained in the water, comprising a main body extending in one direction, a water intake provided on one end side of the main body, a wall portion blocking the other end side of the main body, a first passage and a second passage extending parallel to each other in the one direction inside the main body, a drainage chamber provided inside the main body between the other ends of the first passage and the second passage and the wall portion, an exhaust outlet provided in the wall portion and communicating with the drainage chamber, and a filter provided midway through the first passage to capture the fine dust, wherein one end side of each of the first passage and the second passage is connected to the water intake, the other end side of each of the first passage and the second passage opens into the drainage chamber, and the exhaust outlet is positioned in the wall portion at a position opposite to the opening of the second passage opening into the drainage chamber, rather than opposite to the opening of the first passage opening into the drainage chamber. Effect of the Invention

[0011] According to the present invention, when the direction of water flowing around the fine dust capture device becomes opposite to the direction when the ship is moving forward, fine dust accumulated in the filter can be prevented from separating from the filter and diffusing. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing an outboard motor provided with a fine dust capturing device according to a first embodiment of the present invention; [Diagram 2] 2 is an explanatory diagram showing the lower part of the outboard motor in FIG. 1 as viewed from the left. FIG. [Diagram 3] 2A is an explanatory diagram showing the lower part of the outboard motor in FIG. 1 as seen from the front, and FIG. 2B is an explanatory diagram showing the lower part of the outboard motor in FIG. 1 as seen from the rear. [Figure 4] FIG. 1A is a front view of a micro-dust capture device according to a first embodiment of the present invention, FIG. 1B is a rear view of the micro-dust capture device, FIG. 1C is a left side view of the micro-dust capture device, and FIG. 1D is a plan view of the micro-dust capture device. [Diagram 5] 5 is a cross-sectional view showing the fine dust capturing device taken along the cutting line VV in FIG. 4(A) as viewed from the left. [Figure 6] 6 is a cross-sectional view showing the fine dust capturing device taken along the line VI-VI in FIG. 5 as viewed from the front. [Figure 7] FIG. 2 is an explanatory diagram showing the flow of water in the fine dust capturing device according to the first embodiment of the present invention. [Figure 8] FIG. 4 is a front view of a fine dust capturing device according to a second embodiment of the present invention. [Figure 9] FIG. 6 is an explanatory diagram showing the flow of water in a fine dust capturing device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The fine dust capture device of this embodiment is a device for capturing fine dust contained in water, and is provided in a marine propulsion device and disposed underwater. The fine dust capture device of this embodiment includes a main body extending in one direction, a water intake provided on one end side of the main body, a wall portion closing the other end side of the main body, a first passage and a second passage extending in parallel to each other in the one direction inside the main body, a drainage chamber provided inside the main body between the other ends of the first passage and the second passage and the wall portion, a discharge port provided in the wall portion and communicating with the drainage chamber, and a filter provided midway through the first passage for capturing fine dust.

[0014] In the microdust capture device of this embodiment, one end of each of the first passage and the second passage is connected to the water intake. The other end of each of the first passage and the second passage opens into the drainage chamber. In addition, in the wall portion, the discharge port is disposed at a position opposite to the opening of the second passage that opens into the drainage chamber, not opposite to the opening of the first passage that opens into the drainage chamber.

[0015] In the fine dust capture device of this embodiment, the direction of water flow when water flows from one end side to the other end side of the main body is the forward direction, and the direction of water flow when water flows from the other end side of the main body to one end side is the reverse direction. For example, the fine dust capture device of this embodiment is disposed in a submerged portion of a ship propulsion device, with one end side of the main body facing the front of the ship propulsion device and the other end side of the main body facing the rear of the ship propulsion device. In this case, when water flows from the front to the rear of the ship propulsion device when the ship is moving forward, the direction of water flowing around the fine dust capture device is the forward direction. Also, when water flows from the rear to the front of the ship propulsion device when the ship is moving backward or when the forward moving ship suddenly stops, the direction of water flowing around the fine dust capture device is the reverse direction.

[0016] In the micro-dust capture device of this embodiment, when water flows in the forward direction around the micro-dust capture device, the water flows from the water intake into the first passage and the second passage. The water that flows from the water intake into the first passage flows through the first passage toward the other end of the main body and flows into the drain chamber. The water that flows from the water intake into the second passage flows through the second passage toward the other end of the main body and flows into the drain chamber. The water that flows into the drain chamber flows out of the main body from the discharge port. The water that flows through the first passage from the water intake toward the drain chamber passes through a filter provided midway through the first passage in the forward direction. As the water passes through the filter in the forward direction, micro-dust contained in the water is captured by the filter.

[0017] In addition, in the micro-dust capture device of this embodiment, when water flows in the opposite direction around the micro-dust capture device, the water flows from the discharge port into the drainage chamber. The water that flows from the discharge port into the drainage chamber flows into the first passage and the second passage. At this time, the discharge port is not opposed to the opening of the first passage that opens into the drainage chamber, but is disposed at a position that faces the opening of the second passage that opens into the drainage chamber, so that the path of the flow of the water that flows from the discharge port into the drainage chamber and into the second passage is linear, while the path of the flow of the water that flows from the discharge port into the drainage chamber and into the first passage is curved. Therefore, the water that flows from the discharge port into the drainage chamber is more likely to flow into the second passage than into the first passage. Therefore, the flow rate of the water that flows from the discharge port into the drainage chamber and then into the second passage is greater than the flow rate of the water that flows from the discharge port into the drainage chamber and then into the first passage. As a result, the flow rate of water flowing through the second passage from the discharge chamber to the water intake port is greater than the flow rate of water flowing through the first passage from the discharge chamber to the water intake port. This reduces the flow rate of water passing through the filter in the reverse direction provided in the first passage, and prevents fine dust particles accumulated in the filter from separating from the filter and diffusing. EXAMPLES

[0018] A fine dust trapping device according to a first embodiment of the present invention will be described with reference to Figures 1 to 7. In this embodiment, an outboard motor is taken as an example of a marine propulsion device equipped with the fine dust trapping device. In the embodiment, the directions of up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd) are described according to the arrows drawn at the bottom left or bottom right of each figure.

[0019] (Outboard motor) Fig. 1 shows an outboard motor 1 equipped with a fine dust capture device 21 according to a first embodiment of the present invention, as viewed from the upper left front side. Fig. 2 shows the lower part of the outboard motor 1 as viewed from the left side. Fig. 3(A) shows the lower part of the outboard motor 1 as viewed from the front. Fig. 3(B) shows the lower part of the outboard motor 1 as viewed from the rear.

[0020] The outboard motor 1 is a device that is attached to the transom of a boat to propel the boat. As shown in Fig. 1, the outboard motor 1 includes a propeller unit 2, a battery case 7, a support 8, a transom bracket 17, a swivel bracket 18, a bar handle 19, and a fine dust capture device 21.

[0021] The propeller unit 2 is disposed at the bottom of the outboard motor 1, and is located below the water surface when the outboard motor 1 is attached to the boat. As shown in FIG. 2, the propeller unit 2 includes a motor 3, a propeller shaft 4, a propeller 5, and a propeller unit case 6. The motor 3 is disposed at the front of the propeller unit case 6. The propeller shaft 4 extends in the front-rear direction, and a front part of the propeller shaft 4 is rotatably supported at the rear of the propeller unit case 6. The propeller shaft 4 is connected to the output shaft of the motor 3, or is formed integrally with the output shaft of the motor 3, and rotates by the power of the motor 3. The propeller 5 is fixed to the rear end of the propeller shaft 4, and rotates integrally with the propeller shaft 4. The propeller 5 has a hub 5A and a plurality of blades 5B. The propeller unit case 6 is a sealed case having a cylindrical outer shape.

[0022] 1, the battery case 7 is disposed on top of the outboard motor 1 and is located above the water surface when the outboard motor 1 is attached to a boat. A battery that supplies power to the motor 3 to drive the motor 3 is housed inside the battery case 7.

[0023] The support part 8 is a member that connects the battery case 7 and the propeller unit 2 and supports them. The propeller unit 2 is supported at the lower end of the support part 8, and the battery case 7 is supported at the upper part of the support part 8. Specifically, the support part 8 is formed in a columnar shape extending in the vertical direction, and the propeller unit case 6 is fixed to the lower end of the support part 8. Also, a mounting plate part 15 is fixed to the upper end of the support part 8, and the battery case 7 is detachably attached to the mounting plate part 15. Also, an outboard motor transport handle 16 is provided at the rear of the support part 8 to enable a user to transport the outboard motor 1 removed from the boat.

[0024] The transom bracket 17 is a clamp mechanism that attaches the outboard motor 1 to the transom of a boat. The transom bracket 17 is disposed at the front of the upper portion of the support portion 8.

[0025] The swivel bracket 18 is a bracket for enabling the outboard motor 1 attached to the transom to rotate left and right relative to the boat, and is formed integrally with the rear part of the transom bracket 17. A steering shaft (not shown) is rotatably attached to the swivel bracket 18, and the steering shaft is fixed to the front part of the upper part of the support part 8. The support part 8 can rotate with respect to the swivel bracket 18 about the axis of the steering shaft as the rotation axis, and as a result, the outboard motor 1 can rotate left and right relative to the boat.

[0026] The bar handle 19 is a handle for turning the outboard motor 1 left and right relative to the boat in order to steer the boat. The bar handle 19 is disposed above and in front of the support part 8. Specifically, the bar handle 19 is attached to the end part on the upper front side of the mounting plate part 15. A user can turn the outboard motor 1 right or left relative to the boat by gripping the tip of the bar handle 19 and moving the bar handle 19 left or right, thereby changing the direction of the propeller 5 to the right or left.

[0027] (Configuration of micro-dust capture device) The fine dust capture device 21 is provided in the outboard motor 1 between the lower end of the support part 8 and the propeller unit case 6. When the outboard motor 1 is mounted on a boat, the fine dust capture device 21 is located entirely underwater. The fine dust capture device 21 is a device that captures fine dust dispersed in water areas such as oceans, lakes, or rivers on which the boat navigates.

[0028] Microdust is, for example, minute dust with an outer diameter or maximum length of 0.1 mm or more and 5 mm or less. Plastic waste flows into the sea, lakes, rivers, etc., and is broken down by waves or water currents, or decomposed by ultraviolet rays, etc. into tiny plastic pieces, which may then be dispersed in the water of the sea, lakes, rivers, etc. Such tiny plastic pieces are generally called microplastics. This microplastic falls under the category of microdust.

[0029] Fig. 4 shows the fine dust capturing device 21. In detail, Fig. 4(A) is a front view of the fine dust capturing device 21, Fig. 4(B) is a rear view of the fine dust capturing device 21, Fig. 4(C) is a left side view of the fine dust capturing device 21, and Fig. 4(D) is a plan view of the fine dust capturing device 21. Fig. 5 shows the fine dust capturing device 21 cut along the cutting line VV in Fig. 4(A) as viewed from the left (right in Fig. 4(A)). Fig. 6 shows the fine dust capturing device 21 cut along the cutting line VI-VI in Fig. 5 as viewed from the front (left in Fig. 5).

[0030] As shown in Figures 4 to 6, the fine dust capture device 21 comprises a main body 22 extending in the front-to-rear direction, a water intake port 26 provided at the front end side of the main body 22, a rear wall 27 provided at the rear end side of the main body 22, a first passage 31 and a second passage 32 provided inside the main body 22, a drainage chamber 38 (the area surrounded by a dotted line in Figure 5) provided behind the first passage 31 and the second passage 32 inside the main body 22, an exhaust port 39 provided in the rear wall 27, and a filter 40 provided midway along the first passage 31.

[0031] The main body 22 is formed of, for example, resin or metal. The main body 22 is formed into a cylindrical shape that extends linearly in the front-rear direction when viewed as a whole. K in FIG. 5 is the axis of the main body 22. In this embodiment, the main body 22 is formed into a cylindrical shape with a cross section that is approximately triangular, as shown in FIG. 6. The main body 22 has a passage forming portion 23, a water intake forming portion 24, and a drainage chamber forming portion 25, as shown in FIG. 5. The passage forming portion 23 is formed into a triangular cylindrical shape that extends linearly in the front-rear direction. The water intake forming portion 24 is attached and fixed to the front end side portion of the passage forming portion 23 so as to cover the front end side of the passage forming portion 23. The drainage chamber forming portion 25 is formed into a triangular cylindrical shape with a bottom, and is attached and fixed to the rear end side portion of the passage forming portion 23.

[0032] The water intake 26 is an inlet that takes in water around the outboard motor 1 into the main body 22. As shown in FIG. 4(A), the water intake 26 is formed in the water intake forming portion 24. The water intake 26 is a hole penetrating the water intake forming portion 24. The water intake 26 is disposed in the upper portion of the water intake forming portion 24 so as to face an opening on the front end side of the first passage 31 provided in the upper portion of the passage forming portion 23. Specifically, the water intake 26 is disposed so that its center is located above the center of the water intake forming portion 24, and the center of the water intake 26 is located above the axis K of the main body 22. In this embodiment, the water intake 26 has a substantially triangular shape that is a reduced version of the substantially triangular cross-sectional shape of the main body 22.

[0033] The rear wall portion 27 is a wall that closes the rear end side of the main body portion 22. As shown in Figs. 4(B) and 4(D), the bottom plate of the drainage chamber forming portion 25 corresponds to the rear wall portion 27. The rear wall portion 27 is formed in a flat plate shape. P3 in Fig. 5 indicates the position of the upper end of the inner surface of the rear wall portion 27 in the front-rear direction, and P5 in Fig. 5 indicates the position of the lower end of the inner surface of the rear wall portion 27 in the front-rear direction. As can be seen from positions P3 and P5, the rear wall portion 27 is inclined so that its lower end is located rearward of its upper end. And the inner surface of the rear wall portion 27 facing the drainage chamber 38 is inclined so that its lower end is located rearward of its upper end.

[0034] The first passage 31 is a passage through which water taken in from the water intake 26 flows and through which fine dust particles contained in the water are captured by the filter 40. As shown in FIG. 5, the first passage 31 extends in the front-rear direction in the upper part of the passage forming part 23. The first passage 31 extends linearly from the front end to the rear end of the passage forming part 23. The front end side of the first passage 31 is connected to the water intake 26. The rear end side of the first passage 31 is connected to the drain chamber 38. An opening 31A on the rear end side of the first passage 31 opens to the upper part of the drain chamber 38.

[0035] The second passage 32 is a passage for circulating water (backflow water) flowing from the discharge port 39 into the drain chamber 38 and preventing the water flowing from the discharge port 39 into the drain chamber 38 from flowing back through the first passage 31 and passing through the filter 40 in the opposite direction. The second passage 32 extends in the front-rear direction at the lower part of the passage forming part 23. The second passage 32 extends linearly from the front end to the rear end of the passage forming part 23. The second passage 32 is provided in parallel with the first passage 31. The second passage 32 extends parallel to the first passage 31 and extends in the same direction as the first passage 31. The rear end side of the second passage 32 is connected to the drain chamber 38. An opening 32A at the rear end side of the second passage 32 opens to the lower part of the drain chamber 38.

[0036] The passage forming portion 23 is provided with a partition portion 33 that divides the space in the passage forming portion 23 into an upper portion and a lower portion. The space in the passage forming portion 23 is divided by the partition portion 33, thereby forming a first passage 31 and a second passage 32. The partition portion 33 is formed in a flat plate shape. P1 in FIG. 5 indicates the front end of the passage forming portion 23, that is, the front ends of the first passage 31 and the second passage 32 in the front-rear direction, and P2 in FIG. 5 indicates the front end of the partition portion 33 in the front-rear direction. As can be seen from positions P1 and P2, the front end of the partition portion 33 is located rearward of the front ends of the first passage 31 and the second passage 32. The rear end of the partition portion 33 faces the inside of the drain chamber 38. P3 in FIG. 5 indicates the front-rear direction position of the upper end of the inner surface of the rear wall portion 27, and P4 in FIG. 5 indicates the front-rear direction position of the rear end of the partition portion 33. As can be seen from positions P3 and P4, the rear end of the partition portion 33 is located rearward of the upper end of the inner surface of the rear wall portion 27.

[0037] In addition, a protruding wall 34 is provided at the lower part of the front end part of the water intake port forming part 24. The protruding wall 34 protrudes upward from the lower part of the front end part of the water intake port forming part 24 so as not to block the front of the first passage 31 but to block the front of the second passage 32. As shown in Fig. 4(A) , in the water intake port forming part 24, the lower side of the part where the water intake port 26 is formed forms the protruding wall 34.

[0038] 5, a backflow control surface 35 is formed on the rear surface of the protruding wall 34. The backflow control surface 35 has a function of controlling the flow direction of water that has flowed into the drainage chamber 38 from the discharge port 39, so that the water flows from the rear end side to the front end side in the second passage 32 and then flows into the first passage 31. When the fine dust capture device 21 is viewed from the left, the backflow control surface 35 is curved so as to protrude forward, and the upper end portion of the backflow control surface 35 extends upward and rearward.

[0039] A gap 37 is formed between the upper end of the backflow control surface 35 and the front end of the partition portion 33. This gap 37 serves as a passage for backflow water that flows from the discharge port 39 into the discharge chamber 38 and flows from the rear end side to the front end side in the second passage 32 to flow into the first passage 31. In this embodiment, the second passage 32 is connected to the water intake 26 via the gap 37 and the front end of the first passage 31.

[0040] Further, an inflow control surface 36 is formed on the front surface of the protruding wall 34. The inflow control surface 36 has a function of controlling the flow direction of water so that water flowing from the front toward the fine dust capture device 21 flows into the first passage 31 and proceeds rearward within the first passage 31. When the fine dust capture device 21 is viewed from the left, the inflow control surface 36 is inclined so that its upper end is located rearward of its lower end.

[0041] The drain chamber 38 is a chamber for controlling the water flow so that when water is taken in from the water intake port 26 and flows through the first passage 31, the water flows out from the discharge port 39, and when water flows into the main body 22 from the discharge port 39, the water flows into the second passage 32. The drain chamber 38 is provided inside the main body 22, between the rear ends of the first passage 31 and the second passage 32 and the rear wall 27. Specifically, the inside of the drain chamber forming portion 25 is the drain chamber 38. The rear end side of the first passage 31 opens to the upper part of the drain chamber 38, and the rear end side of the second passage 32 opens to the lower part of the drain chamber 38.

[0042] The discharge port 39 is an opening for discharging water taken in from the water intake port 26, flowing through the first passage 31, and flowing into the discharge chamber 38 to the periphery of the outboard motor 1. As shown in FIG. 4(B), the discharge port 39 is formed in the lower part of the rear wall 27 (the bottom plate of the discharge chamber forming portion 25). The discharge port 39 is a hole penetrating the rear wall 27. The discharge port 39 communicates with the inside of the discharge chamber 38. The discharge port 39 is disposed such that its center is located lower than the center of the discharge chamber forming portion 25, and the center of the discharge port 29 is located lower than the axis K of the main body 22. In this embodiment, the discharge port 29 has a rectangular shape with each corner chamfered, and extends in a direction parallel to the base of the approximately triangular cross section of the main body 22.

[0043] Further, the discharge port 39 is disposed at a position on the rear wall 27 that does not face the opening 31A at the rear end of the first passage 31 that opens into the drainage chamber 38, but faces the opening 32A at the rear end of the second passage 32 that opens into the drainage chamber 38. As shown in FIG. 4B, when the fine dust capture device 21 is viewed from behind, the discharge port 39 overlaps with the opening 32A at the rear end of the second passage 32, but does not overlap at all with the opening 31A at the rear end of the first passage 31. When the fine dust capture device 21 is viewed from behind, the opening 31A at the rear end of the first passage 31 overlaps with a portion of the rear wall 27 where the discharge port 39 is not formed.

[0044] 5 indicates the vertical position of the upper end of the opening 32A on the rear end side of the second passage 32 that opens into the drain chamber 38. Moreover, P7 in Fig. 5 indicates the vertical position of the upper end of the discharge port 39. As can be seen from positions P6 and P7, the upper end of the discharge port 39 is located lower than the upper end of the opening 32A on the rear end side of the second passage 32 that opens into the drain chamber 38.

[0045] The filter 40 captures fine dust contained in the water by passing the water flowing through the first passage 31. The filter 40 is disposed in the rear of the first passage 31 in the main body 22. The filter 40 is provided so as to block the entire cross section of the first passage 31. The filter 40 is formed, for example, in a sheet or plate shape from a nonwoven fabric. Water can pass through the filter 40, but fine dust cannot pass through the filter 40. The outer diameter or maximum length of the fine dust is, for example, 5 mm or less, and the filter 40 capable of capturing such fine dust is a filter with a significantly finer mesh than a filter or strainer for removing, for example, algae in water from the sea, lakes, rivers, etc., caps of plastic bottles, or pebbles stirred up from the bottom of the water.

[0046] In this embodiment, the filter 40 has a multi-layer structure. For example, the filter 40 has a coarse first layer and a fine second layer. The filter 40 is arranged in the first passage 31 so that the first layer is located on the water intake side and the second layer is located on the discharge side. According to such a structure and arrangement of the filter 40, when the water flows backward through the first passage 31, flows from the rear end side to the front end side of the first passage 31, and passes through the filter 40 in the reverse direction, it is possible to suppress the fine dust captured by the filter 40 from being separated from the filter 40 and being diffused. That is, when the water flows forward from the front end side to the rear end side in the first passage 31 and passes through the filter 40 in the forward direction, the fine dust contained in the water is captured by the first layer or the second layer, but when such a forward water flow continues, the fine dust accumulates in the intermediate portion between the first layer and the second layer, or inside the second layer. On the other hand, when water flows in the first passage 31 in the reverse direction from the rear end side to the front end side and passes through the filter 40 in the reverse direction, the fine dust accumulated inside the second layer or in the intermediate portion between the first layer and the second layer is pushed toward the front end side of the first passage 31 by the water. However, at this time, since the fine dust cannot easily pass through the first layer, most of the fine dust remains inside the second layer or in the intermediate portion between the first layer and the second layer. Therefore, the fine dust captured by the filter 40 is prevented from being separated from the filter 40 and diffused due to the backflow of water. The fine dust capture device 21 has the second passage 32 for preventing the water flowing into the drain chamber 38 from the discharge port 39 from flowing back through the first passage 31 and passing through the filter 40 in the reverse direction, so that the flow rate of water passing through the filter 40 in the reverse direction can be reduced, but the flow rate of water passing through the filter 40 in the reverse direction cannot be reduced to zero. Even if water flows in the reverse direction through the filter 40, the multi-layer structure of the filter 40 can prevent the fine dust particles accumulated in the filter 40 from separating from the filter 40 and diffusing.

[0047] The material of the filter 40 is not limited to nonwoven fabric, but may be woven fabric, sponge, glass mat, etc. The filter 40 may be a single layer.

[0048] (Arrangement of micro-dust capture device) As shown in FIG. 1, the fine dust capture device 21 is provided at the lower end of the support part 8, specifically, between the lower end of the support part 8 and the propeller unit case 6. In this embodiment, the lower end of the support part 8 has a bifurcated structure branched in the left and right directions. Specifically, as shown in FIG. 3(A), the lower end of the support part 8 is provided with two connecting parts 9 that are respectively connected to the upper left and upper right parts of the propeller unit case 6. One connecting part 9 extends downward from the left part of the lower end of the support part 8 while inclining to the left, and its lower end is connected to the upper left part of the propeller unit case 6 at approximately the middle part in the front-rear direction. The other connecting part 9 extends downward from the right part of the lower end of the support part 8 while inclining to the right, and its lower end is connected to the upper right part of the propeller unit case 6 at approximately the middle part in the front-rear direction. With this structure, a triangular space is formed between the lower end of the support part 8 and the upper surface of the propeller unit case 6 in a front view. The fine dust capture device 21 is disposed in this space.

[0049] In the fine dust capture device 21, the main body 22 is formed in a triangular tube shape as described above, and the shape of this main body 22 corresponds to the shape of the space between the lower end of the support part 8 and the upper surface of the propeller unit case 6. Therefore, the fine dust capture device 21 is provided so as to fit into the space formed between the lower end of the support part 8 and the upper surface of the propeller unit case 6. With the fine dust capture device 21 provided in the space between the lower end of the support part 8 and the upper surface of the propeller unit case 6, the outer circumferential surface of the fine dust capture device 21 (specifically, the outer circumferential surface of the water intake forming part 24, etc.) contacts the inner surfaces of each connecting part 9 and the upper surface of the propeller unit case 6.

[0050] Furthermore, the main body 22 of the fine dust capture device 21 is disposed in the space between the lower end of the support part 8 and the upper surface of the propeller unit case 6, with its front end facing forward of the outboard motor 1 and its rear end facing rear of the outboard motor 1. Therefore, the water intake 26 faces forward of the outboard motor 1, the first passage 31 and the second passage 32 extend in the fore-and-aft direction of the outboard motor 1, and the discharge port 39 faces rear of the outboard motor 1.

[0051] As shown in Fig. 3(A) when viewing the outboard motor 1 from the front, the water intake 26 is disposed above the propeller unit case 6 and vertically above the center of rotation A of the propeller 5. The water intake 26 is also located in front of the outboard motor 1 and faces in a direction parallel to the axis M (see Fig. 2) of the propeller shaft 4. The water intake 26 faces the water around the outboard motor 1; that is, there are no other passages, such as pipes or tubes, connected to the water intake 26 in front of the water intake 26.

[0052] As shown in Fig. 3(B) when viewing the outboard motor 1 from the rear, the exhaust port 39 is disposed above the propeller unit case 6 and vertically above the center of rotation A of the propeller 5. The exhaust port 39 is located in front of the propeller 5. The exhaust port 39 is located at the rear of the outboard motor 1 and faces in a direction parallel to the axis M of the propeller shaft 4. The exhaust port 39 faces the water around the outboard motor 1; that is, behind the exhaust port 39, there are no other passages such as pipes or tubes connected to the exhaust port 39.

[0053] In this embodiment, the passage forming portion 23 is made of a transparent resin. Also, as shown in Fig. 2, each joint 9 is provided with a window 10. The window 10 is formed by a hole penetrating the joint 9. The transparent passage forming portion 23 is disposed at a position corresponding to the window 10. This allows the user to check the amount of fine dust accumulated in the filter 40 by looking through the window 10 when, for example, the outboard motor 1 is pulled up onto land.

[0054] In this embodiment, the fine dust capture device 21 can be removed from the space formed between the lower end of the support portion 8 and the upper surface of the propeller unit case 6. In the main body 22 of the fine dust capture device 21, the drainage chamber forming portion 25 is detachably attached to the rear of the passage forming portion 23. In addition, the filter 40 is detachably attached to the rear of the passage forming portion 23 in the main body 22. When a user pulls the outboard motor 1 onto the ground, looks through the window 10, and finds that a large amount of fine dust has accumulated in the filter 40, for example, the user can remove the fine dust capture device 21 from the outboard motor 1 to replace the filter 40, etc.

[0055] (Water flow control) In the fine dust capture device 21, the direction of water flow when water flows from the front end side to the rear end side of the main body 22 is the forward direction, and the direction of water flow when water flows from the rear end side to the front end side of the main body 22 is the reverse direction. The fine dust capture device 21 is provided on the outboard motor so that the front end side of the main body 22 faces the front of the outboard motor 1 and the rear end side of the main body 22 faces the rear of the outboard motor 1. Therefore, when water flows from the front to the rear of the outboard motor 1 when the boat is moving forward, the direction of water flowing around the fine dust capture device 21 is the forward direction. Also, when water flows from the rear to the front of the outboard motor 1 when the boat is moving backward or when the boat is suddenly stopped while moving forward, the direction of water flowing around the fine dust capture device 21 is the reverse direction.

[0056] 7(A) is an end view of the fine dust capture device 21 shown in FIG. 5, and shows the flow of water in the main body 22 when the direction of the water flowing around the fine dust capture device 21 is the forward direction. In FIG. 7(A), when the water flows in the forward direction around the fine dust capture device 21, the water flows from the water intake 26 into the first passage 31. At this time, not only the water flowing in a straight line from the front of the main body 22 toward the front end of the main body 22 to the water intake 26, but also the water flowing in a straight line from the front of the propeller unit case 6 to the front end of the propeller unit case 6, and then turns upward and backward along the curved surface of the front end of the propeller unit case 6 to flow toward the front end of the main body 22 (see arrow B in FIG. 2).

[0057] The water flowing into the first passage 31 from the water intake 26 is divided into water flowing through the first passage 31 toward its rear end and water flowing from the front end of the first passage 31 through the gap 37 into the second passage 32. However, the front of the second passage 32 is blocked by the protruding wall 34. The gap 37 also vertically connects the front end of the first passage 31 and the front end of the second passage 32, and the direction of communication is significantly different from the flow direction of the water flowing into the first passage 31 from the water intake 26. Furthermore, an inflow control surface 36 is formed on the front surface of the protruding wall 34, and the inflow control surface 36 is inclined so that its upper end is located rearward of its lower end. Therefore, the water that hits the inflow control surface 36 from the front of the main body 22 is controlled by the inflow control surface 36 and flows upward and backward along the inflow control surface 36 (see arrow C in FIG. 7(A)). Then, the water flows into the first passage 31 and moves rearward inside the first passage 31. Therefore, the flow rate of water flowing from the water intake 26 into the first passage 31 and circulating inside the first passage 31 toward its rear end side is significantly greater than the flow rate of water flowing from the water intake 26 into the first passage 31, passing through the gap 37 from the front end of the first passage 31 and flowing into the second passage 32.

[0058] Water flowing through the first passage 31 toward the rear end side passes in the forward direction through the filter 40. As the water passes through the filter 40 in the forward direction, fine dust particles contained in the water are captured by the filter 40.

[0059] Water that passes through the filter 40 in the forward direction in the first passage 31 flows into the drain chamber 38 and then flows out of the main body 22 from the discharge port 39. At this time, since the inner surface of the rear wall 27 is inclined so that its lower end is located rearward of its upper end, the water that flows from the first passage 31 into the upper part of the drain chamber 38 is controlled by the inclined inner surface of the rear wall 27 and flows downward and rearward along the inner surface of the rear wall 27, and smoothly flows toward the discharge port 39 provided in the lower part of the rear wall 27.

[0060] 7(B) is an end view of the fine dust capture device 21 shown in FIG. 5, and shows the flow of water in the main body 22 when the direction of the water flowing around the fine dust capture device 21 is reversed. In FIG. 7(B), when the water flows in the reverse direction around the fine dust capture device 21, the water flows from the outlet 39 into the drain chamber 38. The water that flows from the outlet 39 into the drain chamber 38 is divided into water that flows into the first passage 31 from the opening 31A at the rear end side of the first passage 31 and flows inside the first passage 31 toward its front end side, and water that flows into the second passage 32 from the opening 32A at the rear end side of the second passage 32 and flows inside the second passage 32 toward its front end side. At this time, the discharge port 39 is not opposed to the opening 31A at the rear end side of the first passage 31 that opens into the drain chamber 38, but is disposed at a position opposed to the opening 32A at the rear end side of the second passage 32 that opens into the drain chamber 38. Therefore, the flow path of the water flowing from the discharge port 39 into the drain chamber 38 and then into the second passage 32 is linear, whereas the flow path of the water flowing from the discharge port 39 into the drain chamber 38 and then into the first passage 31 is curved upward. Therefore, the water that flows into the drain chamber 38 from the discharge port 39 is more likely to flow into the second passage 32 than into the first passage 31. Therefore, the flow rate of the water that flows into the drain chamber 38 from the discharge port 39 and then into the second passage 32 is greater than the flow rate of the water that flows into the drain chamber 38 from the discharge port 39 and then into the first passage 31. As a result, the flow rate of water flowing through the second passage 32 from its rear end to its front end is greater than the flow rate of water flowing through the first passage 31 from its rear end to its front end.

[0061] Furthermore, the rear end of the partition 33 is located rearward of the upper end of the inner surface of the rear wall 27. Since the rear end of the partition 33 is close to the inner surface of the rear wall 27 in this manner, most of the water that flows into the drainage chamber 38 from the discharge port 39 hits the lower surface of the rear end portion of the partition 33 and does not reach the opening 31A on the rear end side of the first passage 31. As a result, the flow rate of water that flows into the first passage 31 after flowing into the drainage chamber 38 from the discharge port 39 is reduced.

[0062] Furthermore, the upper end of the discharge port 39 is located below the upper end of the opening 32A on the rear end side of the second passage 32. As a result, the opening 31A on the rear end side of the first passage 31 and the discharge port 39 are farther apart in the vertical direction than when the position of the upper end of the discharge port 39 is equal to the position of the upper end of the opening 32A on the rear end side of the second passage 32. Therefore, water that has flowed into the drain chamber 38 from the discharge port 39 is less likely to flow into the first passage 31, and the flow rate of water that flows into the first passage 31 after flowing into the drain chamber 38 from the discharge port 39 is further reduced.

[0063] Water that has flowed through the first passage 31 from the drain chamber 38 to the front end of the first passage 31 flows out of the main body 22 from the water intake 26. When water flows through the first passage 31 from the drain chamber 38 to the front end of the first passage 31, the water passes through the filter 40 in the reverse direction. However, as the flow rate of water flowing through the first passage 31 from the drain chamber 38 to the front end of the first passage 31 decreases, the flow rate of water passing through the filter 40 in the reverse direction decreases. Therefore, separation and diffusion of fine dust accumulated in the filter from the filter is suppressed.

[0064] On the other hand, the water that flows from the drainage chamber 38 to the front end of the second passage 32 is controlled by the backflow control surface 35 formed on the rear surface of the protruding wall 34, flows into the first passage 31 through the gap 37, and advances through the first passage 31 from its front end to its rear end. That is, the backflow control surface 35 is curved so as to protrude forward, and the upper end portion of the backflow control surface 35 extends upward and rearward. When the water flowing forward through the second passage 32 hits the backflow control surface 35, the flow direction of the water changes from the front to the upper rear. Then, the water flows through the gap 37 into the front end of the first passage 31 and flows toward the rear end of the first passage 31 (see arrow D in FIG. 7(B)). When the water passes through the filter 40 in the forward direction, fine dust contained in the water is captured by the filter 40. In this way, the fine dust contained in the water is captured by the filter 40 not only when the water flows in the forward direction around the fine dust capturing device 21, but also when the water flows in the reverse direction around the fine dust capturing device 21.

[0065] As described above, the fine dust capture device 21 of the first embodiment of the present invention comprises a main body 22 extending in the front-rear direction, a water intake port 26 provided on the front end side of the main body 22, a rear wall 27 closing the rear end side of the main body 22, a first passage 31 extending in the front-rear direction in an upper part of the main body 22, a second passage 32 extending in the front-rear direction in a lower part of the main body 22, a drainage chamber 38 provided inside the main body 22 between the rear end portions of the first passage 31 and the second passage 32 and the rear wall 27, a discharge port 39 provided in the rear wall 27 and communicating with the drainage chamber 38, and a first passage 31 extending in the front-rear direction in an upper part of the main body 22, a second passage 32 extending in the front-rear direction in a lower part of the main body 22, a drainage chamber 38 provided in the main body 22 between the rear end portions of the first passage 31 and the second passage 32 and the rear wall 27, and a filter 40 for capturing fine dust, the front end of the first passage 31 is connected to the water intake 26, the front end of the second passage 32 is connected to the water intake 26 via a gap 37 and the front end of the first passage 31, the rear ends of the first passage 31 and the second passage 32 open into a drain chamber 38, and in the rear wall 27, the discharge port 39 is disposed at a position opposite to the opening 31A at the rear end of the first passage 31 that opens into the drain chamber 38, but opposite to the opening 32A at the rear end of the second passage 32 that opens into the drain chamber 38. With this configuration, when the water flows in the reverse direction around the fine dust capturing device 21 during reverse travel of the ship or sudden stop of the ship, the flow rate of water flowing from the discharge port 39 into the main body 22 and flowing in the reverse direction in the first passage 31 can be reduced, and therefore the flow rate of water passing through the filter 40 in the reverse direction can be reduced. Therefore, it is possible to prevent the fine dust particles accumulated on the filter 40 from separating from the filter 40 and diffusing.

[0066] Furthermore, by configuring the first passage 31 and the second passage 32, which extend parallel to each other in the front-to-rear direction, to be provided within the main body portion 22, the main body portion 22 can be made compact, and therefore the fine dust capture device 21 can be made smaller.

[0067] The discharge port 39 is disposed at the lower part of the rear wall 27, and the inner surface of the rear wall 27 facing the drain chamber 38 is inclined so that the lower end is located rearward of the upper end. This configuration allows the water flowing from the first passage 31 into the drain chamber 38 to flow smoothly toward the discharge port 39. That is, since the first passage 31 extends in the front-rear direction above the main body 22, the rear end side of the first passage 31 opens to the upper part of the drain chamber 38. On the other hand, the discharge port 39 is disposed at a position on the rear wall 27 that does not face the opening 31A on the rear end side of the first passage 31, specifically, at the lower part of the rear wall 27. As a result, the position of the opening 31A on the rear end side of the first passage 31 and the position of the discharge port 39 are vertically offset. In this case, there is a concern that the smoothness of the flow of water from the opening 31A at the rear end of the first passage 31 toward the discharge port 39 in the discharge chamber 38 may decrease, but in this embodiment, the inner surface of the rear wall 27 is inclined so that its lower end is located further rearward than its upper end. Therefore, the water that flows into the discharge chamber 38 from the opening 31A at the rear end of the first passage 31 flows smoothly along the inclined inner surface of the rear wall 27 toward the discharge port 39.

[0068] Moreover, the main body 22 is formed in a cylindrical shape, and a partition 33 is provided within the main body 22, which divides the space within the main body 22 into upper and lower parts to form the first passage 31 and the second passage 32. With this configuration, the first passage 31 and the second passage 32 can be formed very close to each other within the main body 22, which allows the main body 22 to be formed compactly, and therefore the fine dust capture device 21 can be made smaller.

[0069] In addition, the rear end of the partition 33 faces the inside of the drain chamber 38 and is located rearward of the upper end of the inner surface of the rear wall 27. With this configuration, the distance between the rear end of the partition 33 and the inner surface of the rear wall 27 can be appropriately reduced, and backflow water that has flowed into the drain chamber 38 from the discharge port 39 can be prevented from flowing into the first passage 31 from the opening 31A on the rear end side of the first passage 31.

[0070] In addition, the upper end of the discharge port 39 is located below the upper end of the opening 32A on the rear end side of the second passage 32 that opens into the drain chamber 38. With this configuration, the discharge port 39 can be farther away from the opening 31A on the rear end side of the first passage 31 in the vertical direction than when the position of the upper end of the discharge port 39 is equal to the position of the upper end of the opening 32A on the rear end side of the second passage 32 in the vertical direction. Therefore, the flow rate of backflow water that flows from the discharge port 39 into the drain chamber 38 and then into the first passage 31 can be reduced. In addition, with this configuration, since the first passage 31 and the second passage 32 are very close to each other in the vertical direction, the distance between the discharge port 39 and the opening 31A on the rear end side of the first passage 31 can be increased even when the opening 31A on the rear end side of the first passage 31 and the opening 32A on the rear end side of the second passage 32 are very close to each other in the vertical direction.

[0071] In addition, a protruding wall 34 is provided at the lower part of the front end of the main body 22, protruding upward so as to block the front of the second passage 32 without blocking the front of the first passage 31. In addition, a backflow control surface 35 is formed on the rear surface of the protruding wall 34, which controls the flow direction of the backflow water so that the backflow water that flows from the drain chamber 38 to the front end of the second passage 32 in the second passage 32 then flows into the first passage 31 and proceeds from the front end to the rear end side in the first passage 31. With this configuration, the backflow water that flows into the drain chamber 38 from the discharge port 39 and flows through the second passage 32 can be made to flow into the first passage 31 and pass through the filter 40 in the forward direction. Therefore, the filter 40 can capture fine dust contained in the water not only when the water flows in the forward direction around the fine dust capture device 21, but also when the water flows in the reverse direction around the fine dust capture device 21.

[0072] When the fine dust capture device 21 is viewed from the left or right, the backflow control surface 35 is curved so as to jut out forward, and the upper end portion of the backflow control surface 35 extends upward and rearward. With this configuration, the flow direction of the backflow water that flows from the drain chamber 38 to the front end of the second passage 32 can be controlled so that it then flows into the first passage 31 and proceeds from the front end to the rear end inside the first passage 31, and such control can be realized with a simple configuration.

[0073] Further, on the front surface of the protruding wall 34, an inflow control surface 36 is formed for controlling the flow direction of water so that water flowing from the front toward the fine dust capture device 21 flows into the first passage 31 and proceeds rearward within the first passage 31. With this configuration, the flow rate of water flowing from the water intake 26 through the front end portion of the first passage 31 and the gap 37 into the second passage 32 can be reduced.

[0074] In addition, when the fine dust capture device 21 is viewed from the left or right, the inflow control surface 36 is inclined so that its upper end is located rearward of its lower end. With this configuration, the flow direction of the water flowing from the front toward the fine dust capture device 21 can be controlled so that the water flows into the first passage 31 and moves rearward within the first passage 31, and such control can be realized with a simple configuration. EXAMPLES

[0075] A micro-dust capturing device according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. In the embodiment, when describing the directions of up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd), follow the arrows drawn at the bottom left or bottom right of each figure. In addition, in the micro-dust capturing device according to the second embodiment of the present invention, the same components as those in the micro-dust capturing device according to the first embodiment of the present invention are given the same reference numerals, and their description will be omitted.

[0076] The fine dust capturing device of the second embodiment of the present invention differs from the fine dust capturing device of the first embodiment of the present invention mainly in that there is no protruding wall blocking the front of the second passage.

[0077] Fig. 8 is a front view of a fine dust capture device 51 according to a second embodiment of the present invention. Figs. 9(A) and 9(B) are end views showing a cross section of the fine dust capture device 51 taken along the section line IX-IX in Fig. 8 as viewed from the left (right in Fig. 8). Fig. 9(A) shows the flow of water in the main body 52 when the direction of water flowing around the fine dust capture device 51 is the forward direction. Fig. 9(B) shows the flow of water in the main body 52 when the direction of water flowing around the fine dust capture device 51 is the reverse direction.

[0078] 8 and 9(A), in the main body 52 of the fine dust capture device 51, the water intake forming portion 54 is not provided with a protruding wall. The water intake 56 is disposed at a position where its center coincides with the center of the water intake forming portion 54. The area of ​​the water intake 56 is larger than the area of ​​the water intake 26 in the first embodiment, and the water intake 56 faces both the opening at the front end side of the first passage 31 and the opening at the front end side of the second passage 32. The front end side of the second passage 32 is directly connected to the water intake 56 like the front end side of the first passage 31, and opens forward via the water intake 56 like the front end side of the first passage 31.

[0079] 9(A), when water flows in the forward direction around the fine dust capture device 51, the water flowing from the water intake 56 into the main body 52 is separated into water flowing in the first passage 31 toward its rear end and water flowing in the second passage 32 toward its rear end. The water flowing in the first passage 31 toward its rear end passes through the filter 40, flows into the drain chamber 38, and flows out of the main body 52 from the discharge port 39. The water flowing in the second passage 32 toward its rear end flows into the drain chamber 38, and flows out of the main body 52 from the discharge port 39.

[0080] 9B, when water flows in the reverse direction around the fine dust capture device 21, the water flows from the discharge port 39 into the drainage chamber 38. The water that flows from the discharge port 39 into the drainage chamber 38 is divided into water that flows into the first passage 31 from the opening on the rear end side of the first passage 31 and flows inside the first passage 31 toward its front end side, and water that flows into the second passage 32 from the opening on the rear end side of the second passage 32 and flows inside the second passage 32 toward its front end side. There is no difference between the fine dust capture device 51 of the second embodiment and the fine dust capture device 21 of the first embodiment in the opening on the rear end side of the first passage 31, the opening on the rear end side of the second passage 32, the discharge port 39, the position of the rear end of the partition portion 33, and the position of the upper end of the discharge port 39. Therefore, the flow rate of water flowing from the discharge port 39 into the drainage chamber 38 and then into the second passage 32 is greater than the flow rate of water flowing from the discharge port 39 into the drainage chamber 38 and then into the first passage 31. As a result, the flow rate of water flowing from the rear end side to the front end side in the second passage 32 is greater than the flow rate of water flowing from the rear end side to the front end side in the first passage 31. In addition, in the fine dust capture device 51 of the second embodiment, since a protruding wall that blocks the front of the second passage 32 is not provided, the second passage 32 in the fine dust capture device 51 of the second embodiment is easier for water to flow through than the second passage 32 in the fine dust capture device 21 of the first embodiment, the front of which is blocked by the protruding wall 34. Therefore, the flow rate of water flowing from the rear end side to the front end side in the second passage 32 is greater than that in the first embodiment. Water that flows through the second passage 32 from the drain chamber 38 to the front end of the second passage 32 flows out of the main body 52 from the water intake 56 .

[0081] Furthermore, water that has flowed through the first passage 31 from the drain chamber 38 to the front end of the first passage 31 flows out of the main body 52 from the water intake 56. When water flows through the first passage 31 from the drain chamber 38 to the front end of the first passage 31, the water passes through the filter 40 in the reverse direction, but the flow rate of water flowing through the first passage 31 from the drain chamber 38 to the front end of the first passage 31 decreases, thereby reducing the flow rate of water passing through the filter 40 in the reverse direction. Therefore, separation and diffusion of fine dust accumulated in the filter 40 from the filter 40 is suppressed.

[0082] The fine dust capture device 51 of the second embodiment of the present invention having such a configuration can also reduce the flow rate of water flowing from the outlet 39 into the main body 22 and circulating in the first passage 31 in the reverse direction when water flows around the fine dust capture device 51 in the reverse direction during reverse travel of the ship or sudden stop of the ship, and therefore can reduce the flow rate of water passing through the filter 40 in the reverse direction. Therefore, it is possible to prevent the fine dust accumulated in the filter 40 from separating from the filter 40 and diffusing.

[0083] In each of the above embodiments, the shape of the main body portion 22 (52) is a triangular tube, but the shape of the main body portion 22 (52) is not limited to this and may be, for example, a cylindrical shape or a polygonal tube with four or more sides in cross section.

[0084] In addition, in each of the above embodiments, the fine dust capture device 21 (51) is arranged on the outboard motor 1 with the first passage 31 facing up and the second passage 32 facing down, but the overall orientation of the fine dust capture device 21 may be changed and the fine dust capture device 21 (51) may be arranged on the outboard motor 1 with the first passage 31 facing down and the second passage 32 facing up, or with the first passage 31 facing left (or right) and the second passage 32 facing right (or left).

[0085] In the above first embodiment, the front end of the partition portion 33 is positioned rearward of the front ends of the first passage 31 and the second passage 32 to form the gap 37 between the upper end of the protruding wall 34 and the front end of the partition portion 33, but the present invention is not limited to this. The front end of the partition portion 33 may be positioned at the same position as the front ends of the first passage 31 and the second passage 32 in the front-rear direction, and the entire protruding wall 34 or the upper end of the protruding wall 34 may be positioned forward of the front ends of the first passage 31 and the second passage 32 to form the gap 37 between the upper end of the protruding wall 34 and the front end of the partition portion 33.

[0086] Furthermore, the fine dust capturing device of the present invention can also be applied to marine propulsion devices other than outboard motors.

[0087] 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 the fine dust capture device with such modifications is also included in the technical concept of the present invention. [Explanation of symbols]

[0088] 1. Outboard motor (marine propulsion unit) 21, 51 Fine dust capture device 22, 52 Main body 26, 56 Intake 27 Rear wall (wall) 31 First Passage 31A opening 32 Second Passage 32A opening 33 Partition 34 Projecting wall 35 Backflow Control Surface 36 Inflow control surface 38 Drain room 39 Outlet 40 Filters

Claims

1. A fine dust capture device that is provided in a marine propulsion device and disposed in water to capture fine dust contained in the water, comprising: A main body portion extending in one direction; A water intake provided on one end side of the main body; a wall portion closing the other end side of the main body portion; a first passage and a second passage extending in parallel to each other in the one direction inside the main body; a drainage chamber provided inside the main body between the wall portion and the other end of each of the first passage and the second passage; A drain port provided in the wall portion and communicating with the drain chamber; a filter provided in the first passage for capturing the fine dust; One end side of each of the first passage and the second passage is connected to the water intake port, The other end side of each of the first passage and the second passage opens into the drainage chamber, A fine dust capture device characterized in that, in the wall portion, the exhaust outlet is positioned in a position opposite the opening of the second passage opening into the drainage chamber, rather than opposite the opening of the first passage opening into the drainage chamber.

2. The fine dust capture device described in claim 1, characterized in that, when the extension direction of the main body is the front-to-back direction and the direction perpendicular to the extension direction of the main body is the up-to-down direction, the first passage extends in the front-to-back direction in the upper part of the main body, the second passage extends in the front-to-back direction in the lower part of the main body, the exhaust port is located in the lower part of the wall, and the inner surface of the wall facing the drainage chamber is inclined so that its lower end is located rearward of its upper end.

3. The fine dust capture device described in claim 2, characterized in that the main body is formed in a cylindrical shape, and a partition is provided within the main body to form the first passage and the second passage by dividing the space within the main body into upper and lower parts, and the rear end of the partition faces the drainage chamber and is located rearward of the upper end of the inner surface of the wall portion.

4. The fine dust capture device described in claim 1, characterized in that when the extension direction of the main body is the front-to-back direction and the direction perpendicular to the extension direction of the main body is the up-to-down direction, the first passage extends in the front-to-back direction in the upper part of the main body, the second passage extends in the front-to-back direction in the lower part of the main body, and the upper end of the exhaust outlet is located lower than the upper end of the opening of the second passage that opens into the drainage chamber.

5. The fine dust capture device described in claim 1, characterized in that, when the extension direction of the main body is the front-to-rear direction and the direction perpendicular to the extension direction of the main body is the up-to-down direction, the first passage extends in the front-to-rear direction in the upper part of the main body, and the second passage extends in the front-to-rear direction in the lower part of the main body, a protruding wall that protrudes upward so as to block the front of the second passage but not the front of the first passage is provided at the lower part of the front end of the main body, and a backflow control surface is formed on the rear surface of the protruding wall for controlling the flow direction of the backflow water so that the backflow water that flows from the drain chamber to the front end of the second passage through the second passage then flows into the first passage and proceeds from the front end to the rear end of the first passage.

6. A fine dust capture device as described in claim 5, characterized in that when the fine dust capture device is viewed from the left or right, the backflow control surface is curved so as to protrude forward, and the upper end portion of the backflow control surface extends upward and rearward.

7. The fine dust capture device described in claim 1, characterized in that, when the extension direction of the main body is the front-to-rear direction and the direction perpendicular to the extension direction of the main body is the up-to-down direction, the first passage extends in the front-to-rear direction in the upper part of the main body, and the second passage extends in the front-to-rear direction in the lower part of the main body, a protruding wall that protrudes upwardly is provided at the lower part of the front end of the main body so as to block the front of the second passage but not the front of the first passage, and an inflow control surface is formed on the front surface of the protruding wall for controlling the flow direction of water so that water flowing from the front toward the fine dust capture device flows into the first passage and proceeds rearward within the first passage.

8. 8. The fine dust capture device according to claim 7, wherein the inflow control surface is inclined so that its upper end is positioned rearward of its lower end when the fine dust capture device is viewed from the left or right.

Images