Outboard motors and ships

Abstract

To provide an outboard motor capable of efficiently performing heat exchange between lubricating oil and a heat exchanger in the shift chamber. [Solution] In this outboard motor 100, the shift chamber 30 includes a pipe section 51 through which cooling water flows and a heat exchanger 50 for cooling the lubricating oil. The heat exchanger 50 includes heat transfer fins 52 attached to the pipe section 51.

Description

Technical Field

[0001] This invention relates to an outboard motor and a ship.

Background Art

[0002] Conventionally, an outboard motor including a lower case having a shift chamber configured to allow lubricating oil for lubricating drive system parts to pass through is known (see, for example, Patent Document 1).

[0003] Patent Document 1 describes an outboard motor including a drive system part for transmitting the driving force of an engine to a propeller, and a lower casing (lower case) including a lubricating oil storage chamber (shift chamber) in which a shift shaft is housed and which is formed in a cylindrical shape so as to extend in the vertical direction of the outboard motor body. In the outboard motor described in Patent Document 1, the lubricating oil storage chamber is configured to allow lubricating oil for lubricating drive system parts to pass through. Further, in the outboard motor described in Patent Document 1, a heat exchanger for cooling the lubricating oil including a cooling pipe (pipe part) through which cooling water circulates is provided in the lubricating oil storage chamber. Further, in the outboard motor described in Patent Document 1, the cooling pipe is formed in a meandering shape or a spiral shape in order to increase the contact area with the lubricating oil.

Prior Art Documents

Patent Documents

[0004] ing oil including a cooling pipe (pipe part) through which cooling water circulates is provided in the lubricating oil storage chamber. Further, in the outboard motor described in Patent Document 1, the cooling pipe is formed in a meandering shape or a spiral shape in order to increase the contact area with the lubricating oil.

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the outboard motor described in Patent Document 1, the cooling pipe (pipe section) is formed in a meandering or spiral shape to increase the contact area with the lubricating oil, resulting in a relatively long cooling pipe. In this case, the force of the cooling water supplied from one end of the cooling pipe is not easily maintained until it reaches the other end, so even if the contact area between the cooling pipe and the lubricating oil is increased, efficient heat exchange between the lubricating oil and the heat exchanger cannot be performed. For this reason, a configuration that enables efficient heat exchange between the lubricating oil and the heat exchanger in the lubricating oil storage chamber (shift chamber) is desired.

[0006] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide an outboard motor and a ship capable of efficiently performing heat exchange between lubricating oil and a heat exchanger in the shift chamber. [Means for solving the problem]

[0007] To achieve the above objective, an outboard motor according to the first aspect of this invention comprises a propeller, an engine as a drive source for the propeller, drive system components for transmitting the driving force of the engine to the propeller, a shift shaft for switching the shift state, and a lower case including a shift chamber that houses the shift shaft and is formed in a cylindrical shape so as to extend vertically from the outboard motor body, wherein the shift chamber is configured such that lubricating oil for lubricating the drive system components passes through it, and the shift chamber is provided with a heat exchanger for cooling the lubricating oil, which includes a pipe section through which cooling water flows, and the heat exchanger includes heat transfer fins attached to the pipe section.

[0008] In the outboard motor according to the first aspect of this invention, as described above, the shift chamber is provided with a heat exchanger for cooling the lubricating oil, which includes a pipe section through which cooling water flows, and the heat exchanger includes heat transfer fins attached to the pipe section. This allows for direct heat exchange between the lubricating oil and the pipe section, as well as indirect heat exchange between the lubricating oil and the pipe section via the heat transfer fins attached to the pipe section. In other words, the amount of heat exchanged between the lubricating oil and the pipe section can be increased by the heat transfer fins. In this case, there is no need to make the length of the pipe section relatively long, as in the case where heat transfer fins are not provided, so the force of the cooling water supplied from one end of the pipe section is easily maintained until it reaches the other end of the pipe section. As a result, heat exchange between the lubricating oil and the heat exchanger can be performed efficiently in the shift chamber.

[0009] In the outboard motor according to the first aspect described above, preferably, the pipe section has a U-shape in which a pair of parts extend vertically in the outboard motor body, and the heat transfer fins are attached to the pipe section so as to connect the pair of parts of the pipe section. With this configuration, since the heat transfer fins are arranged to fit between the pair of parts of the pipe section, it is possible to suppress the size of the heat exchanger. As a result, even when the shift chamber is relatively small, a heat exchanger including the pipe section can be easily installed in the shift chamber.

[0010] In the configuration in which the heat transfer fins are attached to the pipe section so as to connect a pair of sections of the pipe section, preferably, multiple heat transfer fins are attached to the pipe section so as to connect a pair of sections of the pipe section and be aligned in the vertical direction of the outboard motor body. With this configuration, the contact area between the lubricating oil and the heat transfer fins can be easily increased, and thus the amount of indirect heat exchange between the lubricating oil and the pipe section via the heat transfer fins can be easily increased.

[0011] In the outboard motor according to the first aspect described above, preferably, a cover member for sealing the shift chamber is attached to the opening at the upper end of the shift chamber, and one end and the other end of the pipe section are attached to the cover member. With this configuration, it is possible to suppress the complexity of the outboard motor structure compared to a case where one end of the pipe section is attached to the cover member and the other end is attached to a part other than the cover member.

[0012] In the configuration in which one end and the other end of the pipe section are attached to the lid member, preferably, one end and the other end of the pipe section are attached to the lid member so as to pass through the lid member. With this configuration, one end and the other end of the pipe section can be easily attached to the lid member.

[0013] In a configuration in which one end and the other end of the pipe section are attached to the lid member so as to pass through the lid member, preferably, one end and the other end of the pipe section are attached to the lid member so as to pass through a through hole or notch formed in the lid member. With this configuration, the through hole or notch formed in the lid member allows one end and the other end of the pipe section to easily pass through the lid member.

[0014] In the outboard motor according to the first aspect described above, preferably, a lubricating oil inlet is formed at the upper part of the shift chamber, and a lubricating oil outlet is formed at the lower end of the shift chamber, with the pipe section extending from the upper end to the lower part within the shift chamber. With this configuration, the pipe section is formed over most of the area through which the lubricating oil passes inside the shift chamber in the vertical direction of the outboard motor body, so that heat exchange can be efficiently performed between the lubricating oil and the pipe section.

[0015] In the outboard motor according to the first aspect described above, preferably, an engine cooling passage through which cooling water for cooling the engine flows, and a water pump provided in the engine cooling passage for circulating the cooling water to the engine are further included, wherein one end of the pipe section is connected to the portion of the engine cooling passage near the discharge port of the water pump. With this configuration, the cooling water flowing through the engine cooling passage can be forcefully supplied from the portion of the engine cooling passage near the discharge port of the water pump to the one end of the pipe section. As a result, the force of the cooling water supplied from one end of the pipe section is easily maintained until it reaches the other end of the pipe section, so that heat exchange between the lubricating oil and the heat exchanger can be performed more efficiently.

[0016] In a configuration where one end of the pipe section is connected to a portion of the engine cooling passage near the water pump outlet, preferably, the other end of the pipe section is connected to a portion of the engine cooling passage downstream of the engine. With this configuration, the cooling water heated by heat exchange with lubricating oil in the shift chamber can be discharged from the other end of the pipe section to the portion of the engine cooling passage downstream of the engine. This allows the cooling water heated by heat exchange with lubricating oil in the shift chamber to be mixed with the cooling water heated by cooling the engine in the engine cooling passage and easily discharged to the outside of the outboard motor.

[0017] In the outboard motor according to the first aspect described above, preferably, the pipe section has an inner diameter of approximately 4 mm or more. With this configuration, in a typical outboard motor where cooling water is drawn in from outside the outboard motor, it is possible to suppress the clogging of the pipe section by foreign matter such as gravel mixed in with the cooling water.

[0018] Furthermore, in order to achieve the above objective, a vessel according to a second aspect of this invention comprises a hull and an outboard motor attached to the stern of the hull, the outboard motor comprising a propeller, an engine as a drive source for the propeller, drive system components for transmitting the driving force of the engine to the propeller, a shift shaft for switching the shift state, and a lower case including a shift chamber that houses the shift shaft and is formed in a cylindrical shape to extend vertically from the outboard motor body, the shift chamber is configured such that lubricating oil for lubricating the drive system components passes through it, the shift chamber is provided with a heat exchanger for cooling the lubricating oil and includes a pipe section through which cooling water flows, the heat exchanger includes heat transfer fins attached to the pipe section.

[0019] In a vessel according to the second aspect of this invention, as described above, the shift chamber includes a pipe section through which cooling water flows and is equipped with a heat exchanger for cooling the lubricating oil, and the heat exchanger includes heat transfer fins attached to the pipe section. As a result, in addition to direct heat exchange between the lubricating oil and the pipe section, similar to the outboard motor according to the first aspect, heat exchange can also be performed indirectly between the lubricating oil and the pipe section via the heat transfer fins attached to the pipe section. That is, the amount of heat exchange between the lubricating oil and the pipe section can be increased by the heat transfer fins. In this case, similar to the outboard motor according to the first aspect, there is no need to make the length of the pipe section relatively long, as in the case where heat transfer fins are not provided, so the force of the cooling water supplied from one end of the pipe section is easily maintained until it reaches the other end of the pipe section. Also, similar to the outboard motor according to the first aspect, there is no need to provide members that connect the inside and outside of the shift chamber in the outboard motor. As a result, similar to the outboard motor according to the first aspect, heat exchange between the lubricating oil and the heat exchanger can be performed efficiently in the shift chamber.

[0020] In the vessel according to the second aspect described above, preferably, the pipe section has a U-shape in which a pair of parts extend vertically from the outboard motor body, and the heat transfer fins are attached to the pipe section so as to connect the pair of parts of the pipe section. With this configuration, similar to the outboard motor according to the first aspect described above, even if the shift chamber is relatively small, a heat exchanger including the pipe section can be easily installed in the shift chamber.

[0021] In the configuration of the ship according to the second aspect described above, in which the heat transfer fins are attached to the pipe section so as to connect a pair of sections of the pipe section, preferably, a plurality of heat transfer fins are attached to the pipe section so as to connect a pair of sections of the pipe section and so as to be aligned in the vertical direction of the outboard motor body. With this configuration, similar to the outboard motor according to the first aspect described above, the amount of heat exchange between the indirect lubricating oil and the pipe section via the heat transfer fins can be easily increased.

[0022] In the vessel according to the second aspect described above, preferably, a cover member for sealing the shift chamber is attached to the opening at the upper end of the shift chamber, and one end and the other end of the pipe section are attached to the cover member. With this configuration, it is possible to suppress the complexity of the outboard motor structure compared to the outboard motor according to the first aspect described above, where one end and the other end of the pipe section are attached to the cover member and the other end is attached to a part other than the cover member.

[0023] In the configuration described in the second aspect above, where one end and the other end of the pipe section of the vessel are attached to the cover member, preferably, the one end and the other end of the pipe section are attached to the cover member so as to penetrate the cover member. With this configuration, similar to the outboard motor described in the first aspect above, the one end and the other end of the pipe section can be easily attached to the cover member.

[0024] In a configuration where the pipe portion of the ship according to the second aspect is attached to the lid member such that one end and the other end of the pipe portion penetrate through the lid member, preferably, one end and the other end of the pipe portion are attached to the lid member so as to penetrate through a through-hole or notch formed in the lid member. With this configuration, similar to the outboard motor according to the first aspect, the through-hole or notch formed in the lid member can easily allow one end and the other end of the pipe portion to penetrate through the lid member.

[0025] In the ship according to the second aspect, preferably, an inlet for lubricating oil is formed at the upper part of the shift chamber, and an outlet for lubricating oil is formed at the lower end of the shift chamber. The pipe portion extends from the upper end to the lower part within the shift chamber. With this configuration, similar to the outboard motor according to the first aspect, since the pipe portion is formed over most of the range where the lubricating oil passes through the inside of the shift chamber in the vertical direction of the outboard motor main body, efficient heat exchange can be achieved between the lubricating oil and the pipe portion.

[0026] In the ship according to the second aspect, preferably, it further includes an engine cooling flow path through which cooling water for cooling the engine circulates, and a water pump provided in the engine cooling flow path for circulating the cooling water to the engine. One end of the pipe portion is connected to a portion near the discharge port of the water pump in the engine cooling flow path. With this configuration, similar to the outboard motor according to the first aspect, the cooling water flowing through the engine cooling flow path can be vigorously supplied from a portion near the discharge port of the water pump in the engine cooling flow path to one end of the pipe portion. Thereby, similar to the outboard motor according to the first aspect, the momentum of the cooling water supplied from one end of the pipe portion is likely to be maintained until it reaches the other end of the pipe portion, so that heat exchange between the lubricating oil and the heat exchanger can be performed more efficiently.

[0027] In the configuration where one end of the pipe portion of the ship according to the second aspect is connected to a portion near the discharge port of the water pump in the engine cooling flow path, preferably, the other end of the pipe portion is connected to a portion downstream of the engine in the engine cooling flow path. With this configuration, similar to the outboard motor according to the first aspect, the cooling water heated by exchanging heat with the lubricating oil in the shift chamber can be discharged from the other end of the pipe to the downstream side of the engine in the engine cooling flow path. Thereby, similar to the outboard motor according to the first aspect, the cooling water heated by exchanging heat with the lubricating oil in the shift chamber can be easily discharged to the outside of the outboard motor by being mixed into the cooling water that has cooled and warmed the engine in the engine cooling flow path.

[0028] In the ship according to the second aspect, preferably, the pipe portion has an inner diameter of at least approximately 4 mm. With this configuration, similar to the outboard motor according to the first aspect, in a general outboard motor where cooling water is taken in from the outside of the outboard motor, it is possible to suppress foreign substances such as gravel mixed in the cooling water from clogging the pipe portion.

Advantages of the Invention

[0029] According to the present invention, as described above, it is possible to provide an outboard motor and a ship capable of efficiently performing heat exchange between the lubricating oil and the heat exchanger in the shift chamber.

Brief Description of the Drawings

[0030] [Figure 1] It is a perspective view of a ship according to an embodiment of the present invention. [Figure 2] It is a side view of an outboard motor according to an embodiment of the present invention. [Figure 3] It is a cross-sectional view of the lower case of an outboard motor according to an embodiment of the present invention. [Figure 4] It is a cross-sectional view taken along line IV-IV of FIG. 3. [Figure 5] It is a block diagram showing the cooling flow path of an outboard motor according to an embodiment of the present invention. [Figure 6]This is a cross-sectional view of the heat exchanger of an outboard motor according to one embodiment of the present invention, as seen from the front of the outboard motor body. [Modes for carrying out the invention]

[0031] The following describes embodiments of the present invention based on the drawings.

[0032] An outboard motor 100 and a vessel 120 according to one embodiment of the present invention will be described with reference to Figures 1 to 6.

[0033] (Ship composition) As shown in Figure 1, the vessel 120 comprises a hull 110 and an outboard motor 100. Only one outboard motor 100 is mounted on the stern 111 of the hull 110. The vessel 120 is a relatively small vessel. The vessel 120 is a relatively small vessel used, for example, for sightseeing or fishing.

[0034] (Outboard motor configuration) As shown in Figure 2, the outboard motor 100 includes an outboard motor body 101 and a bracket 102. The outboard motor body 101 is attached via the bracket 102 to a transom 112 located at the stern 111 of the hull 110. In the figure, FWD, BWD, L, R, Z1, and Z2 indicate the front, rear, left, right, top, and bottom of the outboard motor body 101, respectively.

[0035] The outboard motor 100 is an engine-driven outboard motor configured to drive a propeller 12 with an engine 11. Specifically, the outboard motor body 101 includes an engine 11, a drive system component PD, and a propeller 12. The engine 11 is an internal combustion engine that generates driving force. The engine 11 is the drive source for the propeller 12. The drive system component PD is configured to transmit the driving force of the engine 11 to the propeller 12. The propeller 12 rotates in the water due to the driving force transmitted from the engine 11, thereby generating thrust to propel the hull 110.

[0036] The drivetrain components PD include a drive shaft 13, a gear section 14, and a propeller shaft 15. The drive shaft 13 is positioned to extend along the vertical direction of the outboard motor body 101. The upper end of the drive shaft 13 is connected to the crankshaft (not shown) of the engine 11. The lower end of the drive shaft 13 is connected to the gear section 14. The propeller shaft 15 is positioned to extend along the longitudinal direction of the outboard motor body 101. The front end of the propeller shaft 15 is connected to the gear section 14. The rear end of the propeller shaft 15 is connected to the propeller 12. The driving force of the engine 11 is transmitted to the propeller 12 via the drive shaft 13, the gear section 14, and the propeller shaft 15.

[0037] The outboard motor body 101 includes a shift actuator 16 and a shift switching component SC. The shift actuator 16 and the shift switching component SC are provided to switch the shift state of the outboard motor 100 between a forward state, a reverse state, and a neutral state. Specifically, the driving force from the shift actuator 16 is transmitted to the gear section 14 via the shift switching component SC to switch the meshing of the gears in the gear section 14. The shift switching component SC includes a shift shaft 17. The forward state is the state in which the driving force of the engine 11 is transmitted to the propeller 12 so as to generate forward thrust in the propeller 12. The reverse state is the state in which the driving force of the engine 11 is transmitted to the propeller 12 so as to generate backward thrust in the propeller 12. The neutral state is the state in which the driving force of the engine 11 is not transmitted to the propeller 12.

[0038] The outboard motor body 101 includes a cowl 21, an upper case 22, and a lower case 23. The cowl 21, upper case 22, and lower case 23 constitute the housing of the outboard motor body 101. Of the cowl 21, upper case 22, and lower case 23, at least the lower case 23 is made of a metal with relatively high thermal conductivity (for example, aluminum). The cowl 21 houses the engine 11 and the shift actuator 16. The upper case 22 is located below the cowl 21. The upper case 22 houses the upper part of the drive shaft 13 and the upper part of the shift shaft 17. The lower case 23 is located below the upper case 22. The lower case 23 houses the lower part of the drive shaft 13, the gear section 14, the propeller shaft 15, and the lower part of the shift shaft 17. The propeller 12 is located behind the lower case 23.

[0039] (Lower case structure) As shown in Figure 3, the lower case 23 includes a shaft insertion hole 23a, a gear chamber 23b, and a shift chamber 30. The shaft insertion hole 23a is formed to extend vertically from the outboard motor body 101. The lower part of the drive shaft 13 is inserted into the shaft insertion hole 23a. The gear chamber 23b is located below the shaft insertion hole 23a. The gear section 14 is housed in the gear chamber 23b. The shift chamber 30 is located in front of the shaft insertion hole 23a. The shift chamber 30 is formed in a cylindrical shape to extend vertically from the outboard motor body 101. The lower part of the shift shaft 17 is housed in the shift chamber 30.

[0040] The shaft insertion hole 23a, gear chamber 23b, and shift chamber 30 form a storage area for lubricating oil to lubricate the drive system components PD. Specifically, the lower end of the shaft insertion hole 23a is connected to the upper end of the gear chamber 23b. The upper part of the shaft insertion hole 23a and the upper part 30a of the shift chamber 30 are connected by a first lubricating oil passage 23c formed between the shaft insertion hole 23a and the shift chamber 30. The lower end 30b of the shift chamber 30 and the gear chamber 23b are connected by a second lubricating oil passage 23d between the shift chamber 30 and the gear chamber 23b. The upper end of the shaft insertion hole 23a and the rear of the gear chamber 23b are sealed by a sealing member. A lid member 31 is attached to the opening 30d of the upper end 30c of the shift chamber 30 to seal the shift chamber 30. Lubricating oil is stored in the storage area formed by the shaft insertion hole 23a, gear chamber 23b, and shift chamber 30.

[0041] The shift chamber 30 is configured to allow lubricating oil to pass through. Specifically, a helical groove (not shown) is formed on the outer surface of the drive shaft 13 in the portion inserted into the shaft insertion hole 23a. The helical groove formed on the outer surface of the drive shaft 13 is designed so that when the drive shaft 13 rotates, the lubricating oil between the helical groove of the drive shaft 13 and the inner surface of the shaft insertion hole 23a flows upward along the helical groove. As a result, when the drive shaft 13 is rotating due to the driving force of the engine 11 (see Figure 2), the lubricating oil flows from the gear chamber 23b to the shaft insertion hole 23a, from the shaft insertion hole 23a to the shift chamber 30 via the first lubricating oil passage 23c, from the shift chamber 30 to the gear chamber 23b via the second lubricating oil passage 23d, and then again from the gear chamber 23b to the shaft insertion hole 23a. In other words, when the drive shaft 13 is rotating, the lubricating oil circulates in the following order: shaft insertion hole 23a, shift chamber 30, gear chamber 23b, shaft insertion hole 23a, ...

[0042] (Shift room configuration) As shown in Figure 3, a lubricating oil inlet 30e is formed in the upper part 30a of the shift chamber 30. A lubricating oil outlet 30g is formed in the bottom surface 30f of the shift chamber 30. Specifically, the lubricating oil outlet 30g is formed at the lower end 30b of the shift chamber 30. Furthermore, a shaft through-hole 30h is formed in the bottom surface 30f of the shift chamber 30, through which the shift shaft 17 passes. The shaft through-hole 30h is located in front of the lubricating oil outlet 30g.

[0043] As shown in Figure 4, the lubricating oil outlet 30g and the shaft through-hole 30h are formed on the bottom surface 30f of the shift chamber 30, in the central part 30i of the outboard motor body 101 in the left-right direction when viewed in the vertical direction of the outboard motor body 101. The lubricating oil outlet 30g and the shaft through-hole 30h are formed so as to be aligned in the front-rear direction of the outboard motor body 101 on the bottom surface 30f of the shift chamber 30.

[0044] (Engine cooling channel configuration) As shown in Figure 5, the outboard motor 100 includes an engine cooling passage 40 and a water pump 41. Cooling water for cooling the engine 11 flows through the engine cooling passage 40. The cooling water is taken into the engine cooling passage 40 from outside the outboard motor body 101 via an intake port 40a. The intake port 40a is formed in the lower case 23 (see Figure 2). The water pump 41 is provided in the engine cooling passage 40 and is configured to circulate the cooling water to the engine 11. As shown in Figure 3, the water pump 41 is located near the lower end of the upper case 22 and near the drive shaft 13. The water pump 41 is configured to be driven in conjunction with the rotation of the drive shaft 13. As shown in Figure 5, the cooling water that has cooled the engine 11 is discharged to the outside of the outboard motor body 101 from an outlet port 40b. The outlet port 40b is formed in the lower case 23.

[0045] (Heat exchanger configuration) As shown in Figure 6, the shift chamber 30 is provided with a heat exchanger 50 for cooling the lubricating oil, which includes a pipe section 51 through which cooling water flows. As the pipe section 51 is continuously cooled by the flow of cooling water through it, heat exchange takes place between the pipe section 51 and the lubricating oil in contact with the pipe section 51. In other words, heat exchange takes place between the cooling water passing through the pipe section 51 and the lubricating oil in contact with the pipe section 51 via the pipe section 51.

[0046] As shown in Figure 4, the pipe section 51 has an inner diameter Φ of approximately 4 mm or more. The inner diameter Φ of the pipe section 51 is set based on the size of foreign matter such as gravel that is expected to be mixed into the cooling water taken in from outside the outboard motor 100 (see Figure 2).

[0047] As shown in Figure 6, the pipe section 51 extends within the shift chamber 30 from the upper end 30c to the lower end 30j. When viewed from the front-rear direction of the outboard motor body 101, the pipe section 51 has a U-shape in which a pair of sections 51a extend in the vertical direction of the outboard motor body 101. One end 51b and the other end 51c of the pipe section 51 are attached to the cover member 31 so as to pass through a through hole 31a formed in the cover member 31. The tips of the one end 51b and the other end 51c of the pipe section 51 are positioned in the upper case 22.

[0048] As shown in Figure 5, one end 51b of the pipe section 51 is connected to a portion 40c of the engine cooling passage 40 near the discharge port 41a of the water pump 41. This portion 40c is located at the lower end of the upper case 22 (see Figure 2). The other end 51c of the pipe section 51 is connected to a portion 40d of the engine cooling passage 40 downstream of the engine 11. This downstream portion 40d is located in the upper case 22 or the lower case 23 (see Figure 2).

[0049] As shown in Figure 6, the heat exchanger 50 includes heat transfer fins (cooling fins) 52 attached to the pipe section 51. While the pipe section 51 is continuously cooled by the flow of cooling water through it, heat exchange occurs between the heat transfer fins 52 and the lubricating oil in contact with the heat transfer fins 52. Thus, indirect heat exchange occurs between the pipe section 51 to which the heat transfer fins 52 are attached and the lubricating oil in contact with the heat transfer fins 52 via the heat transfer fins 52. In other words, heat exchange occurs between the cooling water passing through the pipe section 51 and the lubricating oil in contact with the heat transfer fins 52 via the heat transfer fins 52 and the pipe section 51.

[0050] Multiple heat transfer fins 52 are attached to the pipe section 51 so as to connect pairs of sections 51a of the pipe section 51 and to be aligned vertically on the outboard motor body 101. In Figure 6, an example is shown in which the heat transfer fins 52 are formed in a flat plate shape, but they may be formed in a shape other than a flat plate.

[0051] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0052] In this embodiment, as described above, the shift chamber 30 is provided with a heat exchanger 50 for cooling the lubricating oil, which includes a pipe section 51 through which cooling water flows. The heat exchanger 50 includes heat transfer fins 52 attached to the pipe section 51. This allows for direct heat exchange between the lubricating oil and the pipe section 51, as well as indirect heat exchange between the lubricating oil and the pipe section 51 via the heat transfer fins 52 attached to the pipe section 51. In this case, there is no need to make the length of the pipe section 51 relatively long, as would be the case if the heat transfer fins 52 were not provided, so the force of the cooling water supplied from one end 51b of the pipe section 51 is easily maintained until it reaches the other end 51c of the pipe section 51. As a result, heat exchange between the lubricating oil and the heat exchanger 50 can be efficiently performed in the shift chamber 30.

[0053] Furthermore, in this embodiment, as described above, the pipe section 51 has a U-shape in which a pair of sections 51a extend vertically from the outboard motor body 101. The heat transfer fins 52 are attached to the pipe section 51 so as to connect the pair of sections 51a of the pipe section 51. As a result, the heat transfer fins 52 are positioned to fit between the pair of sections 51a of the pipe section 51, which helps to suppress the size of the heat exchanger 50. This makes it possible to easily install a heat exchanger 50 including the pipe section 51 in the shift chamber 30 even when the shift chamber 30 is relatively small.

[0054] Furthermore, in this embodiment, as described above, multiple heat transfer fins 52 are attached to the pipe section 51 so as to connect pairs of sections 51a of the pipe section 51 and be aligned in the vertical direction of the outboard motor body 101. This makes it easy to increase the contact area between the lubricating oil and the heat transfer fins 52, and thus easily increases the amount of indirect heat exchange between the lubricating oil and the pipe section 51 via the heat transfer fins 52.

[0055] Furthermore, in this embodiment, as described above, a lid member 31 for sealing the shift chamber 30 is attached to the opening 30d at the upper end 30c of the shift chamber 30. Also, one end 51b and the other end 51c of the pipe section 51 are attached to the lid member 31. This makes it possible to suppress the complexity of the structure of the outboard motor 100 compared to the case where one end 51b and the other end 51c of the pipe section 51 are attached to the lid member 31 and the other end 51b and the other end 51c of the pipe section 51 are attached to a part other than the lid member 31.

[0056] Furthermore, in this embodiment, as described above, one end 51b and the other end 51c of the pipe portion 51 are attached to the lid member 31 so as to pass through the lid member 31. This makes it easy to attach one end 51b and the other end 51c of the pipe portion 51 to the lid member 31.

[0057] Furthermore, in this embodiment, as described above, one end 51b and the other end 51c of the pipe portion 51 are attached to the lid member 31 so as to pass through the through hole 31a formed in the lid member 31. This allows the one end 51b and the other end 51c of the pipe portion 51 to easily pass through the lid member 31 via the through hole 31a formed in the lid member 31.

[0058] Furthermore, in this embodiment, as described above, a lubricating oil inlet 30e is formed in the upper part 30a of the shift chamber 30. Also, a lubricating oil outlet 30g is formed in the lower end 30b of the shift chamber 30. The pipe section 51 extends from the upper end 30c to the lower part 30j within the shift chamber 30. As a result, the pipe section 51 is formed over most of the range through which the lubricating oil passes inside the shift chamber 30 in the vertical direction of the outboard motor body 101, so that heat exchange can be efficiently performed between the lubricating oil and the pipe section 51.

[0059] Furthermore, in this embodiment, as described above, the outboard motor 100 includes an engine cooling passage 40 through which cooling water for cooling the engine 11 flows, and a water pump 41 provided in the engine cooling passage 40 for circulating the cooling water to the engine 11. In addition, one end 51b of the pipe section 51 is connected to a portion 40c of the engine cooling passage 40 near the discharge port 41a of the water pump 41. This allows the cooling water flowing through the engine cooling passage 40 to be forcefully supplied from the portion 40c of the engine cooling passage 40 near the discharge port 41a of the water pump 41 to the one end 51b of the pipe section 51. As a result, the force of the cooling water supplied from one end 51b of the pipe section 51 is easily maintained until it reaches the other end 51c of the pipe section 51, so that heat exchange between the lubricating oil and the heat exchanger 50 can be performed more efficiently.

[0060] Furthermore, in this embodiment, as described above, the other end 51c of the pipe section 51 is connected to the portion 40d of the engine cooling passage 40 that is downstream of the engine 11. This allows the cooling water, which has been heated by heat exchange with the lubricating oil in the shift chamber 30, to be discharged from the other end 51c of the pipe section 51 to the portion 40d of the engine cooling passage 40 that is downstream of the engine 11. This allows the cooling water, which has been heated by heat exchange with the lubricating oil in the shift chamber 30, to be mixed with the cooling water in the engine cooling passage 40 that has been heated by cooling the engine 11, and easily discharged to the outside of the outboard motor 100.

[0061] Furthermore, in this embodiment, as described above, the pipe section 51 has an inner diameter Φ of approximately 4 mm or more. This makes it possible to prevent foreign matter such as gravel mixed in the cooling water from clogging the pipe section 51 in a typical outboard motor 100 in which cooling water is taken in from outside the outboard motor 100.

[0062] [Differentiation] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0063] For example, in the above embodiment, an example was shown in which the pipe portion 51 has an inner diameter Φ of approximately 4 mm or more, but the present invention is not limited thereto. In the present invention, the pipe portion may have an inner diameter of less than approximately 4 mm.

[0064] Furthermore, although the above embodiment shows an example in which the other end 51c of the pipe section 51 is connected to the portion 40d of the engine cooling passage 40 that is downstream of the engine 11, the present invention is not limited to this. In the present invention, the other end of the pipe section may be connected to a portion of the engine cooling passage other than the portion downstream of the engine (for example, a portion of the engine cooling passage that is downstream of the portion near the water pump discharge port and upstream of the engine).

[0065] Furthermore, although the above embodiment shows an example in which one end 51b of the pipe section 51 is connected to a portion 40c of the engine cooling passage 40 near the discharge port 41a of the water pump 41, the present invention is not limited to this. In the present invention, one end of the pipe section may be connected to a portion of the engine cooling passage other than the portion near the discharge port of the water pump (for example, a portion of the engine cooling passage upstream of the water pump).

[0066] Furthermore, although the above embodiment shows an example in which the pipe portion 51 extends from the upper end 30c to the lower end 30j within the shift chamber 30, the present invention is not limited to this. In the present invention, the pipe portion may extend only to a portion of the shift chamber from the upper end to the lower end.

[0067] Furthermore, in the above embodiment, an example was shown in which one end 51b and the other end 51c of the pipe portion 51 are attached to the lid member 31 so as to pass through a through hole 31a formed in the lid member 31, but the present invention is not limited to this. In the present invention, one end and the other end of the pipe portion may be attached to the lid member so as to pass through a notch formed in the lid member.

[0068] Furthermore, although the above embodiment shows an example in which one end 51b and the other end 51c of the pipe portion 51 are attached to the lid member 31 so as to penetrate the lid member 31, the present invention is not limited to this. In the present invention, one end and the other end of the pipe portion may be attached to the lid member so as not to penetrate the lid member.

[0069] Furthermore, although the above embodiment shows an example in which one end 51b and the other end 51c of the pipe portion 51 are attached to the lid member 31, the present invention is not limited to this. In the present invention, only one of the ends of the pipe portion may be attached to the lid member, or both ends of the pipe portion may not be attached to the lid member.

[0070] Furthermore, in the above embodiment, an example was shown in which multiple heat transfer fins 52 are attached to the pipe section 51 so as to connect a pair of sections 51a of the pipe section 51 and be aligned in the vertical direction of the outboard motor body 101, but the present invention is not limited to this. In the present invention, only one heat transfer fin may be attached to the pipe section so as to connect a pair of sections of the pipe section.

[0071] Furthermore, although the above embodiment shows an example in which the heat transfer fins 52 are attached to the pipe portion 51 so as to connect a pair of portions 51a of the pipe portion 51, the present invention is not limited to this. In the present invention, the heat transfer fins may be attached to the pipe portion so as not to connect a pair of portions of the pipe portion.

[0072] Furthermore, in the above embodiment, an example was shown in which the pipe section 51 has a U-shape in which a pair of portions 51a extend in the vertical direction of the outboard motor body 101 when viewed from the front-rear direction of the outboard motor body 101, but the present invention is not limited to this. In the present invention, the pipe section may have a U-shape when viewed from a direction other than the front-rear direction of the outboard motor body.

[0073] Furthermore, although the above embodiment shows an example in which the pipe section 51 has a U-shape in which a pair of portions 51a extend vertically in the outboard motor body 101, the present invention is not limited to this. In the present invention, the pipe section may have a shape other than a U-shape.

[0074] Furthermore, although the above embodiment shows an example in which the shaft through-hole 30h is formed in front of the lubricating oil outlet 30g, the present invention is not limited to this. In the present invention, the shaft through-hole may be formed behind the lubricating oil outlet, or it may be formed both in front of and behind the lubricating oil outlet.

[0075] Furthermore, in the above embodiment, an example was shown in which the lubricating oil outlet 30g and the shaft through hole 30h are formed so as to be aligned in the front-rear direction of the outboard motor body 101 on the bottom surface 30f of the shift chamber 30, but the present invention is not limited to this. In the present invention, the lubricating oil outlet and the shaft through hole may be formed so as not to be aligned in the front-rear direction of the outboard motor body on the bottom surface of the shift chamber.

[0076] Furthermore, although the above embodiment shows an example in which only one outboard motor 100 is attached to the stern 111 of the hull 110, the present invention is not limited to this. In the present invention, multiple outboard motors may be attached to the stern of the hull. [Explanation of Symbols]

[0077] 11 Engine 12 propellers 17 Shift shaft 23 Lower Cases 30 Shift Room 30a Upper part (of the shift room) 30b Lower end (of the shift room) 30c (Upper part of the shift chamber) 30d (Opening at the top of the shift compartment) 30e Lubricant Inlet 30g lubricant outlet 30j (lower part of the shift room) 31 Lid member 31a Through hole (of the lid member) 40 Engine cooling passages 40c (the area near the water pump outlet in the engine cooling passage) 40d (The part of the engine cooling passage that is downstream of the engine) 41 Water pump 41a (Water pump) outlet 50 heat exchanger 51 Pipe section 51a A pair of parts (of the pipe section) 51b One end (of the pipe section) 51c (The other end of the pipe section) 52 heat transfer fins 100 Outboard motors 101 Outboard motor body 110 hull 120 Ships PD drive system components Φ (Inner diameter of the pipe section)

Claims

1. Propeller and, The engine serves as the power source for the aforementioned propeller, A drive system component for transmitting the driving force of the engine to the propeller, A shift shaft for switching the shift state, The outboard motor body includes a lower case which contains a shift chamber formed in a cylindrical shape that houses the shift shaft and extends vertically, The shift chamber is configured such that lubricating oil for lubricating the drive system components passes through it. The shift chamber is equipped with a heat exchanger for cooling the lubricating oil, which includes a pipe section through which cooling water flows. The heat exchanger is an outboard motor, including heat transfer fins attached to the pipe section.

2. The pipe section has a U-shape in which one pair of parts extend vertically from the outboard motor body. The outboard motor according to claim 1, wherein the heat transfer fins are attached to the pipe portion so as to connect the pair of portions of the pipe portion.

3. The outboard motor according to claim 2, wherein a plurality of the heat transfer fins are attached to the pipe portion so as to connect the pair of portions of the pipe portion and to be aligned in the vertical direction of the outboard motor body.

4. A cover member is attached to the opening at the upper end of the shift chamber to seal the shift chamber. The outboard motor according to claim 1, wherein one end and the other end of the pipe section are attached to the cover member.

5. The outboard motor according to claim 4, wherein one end and the other end of the pipe section are attached to the cover member so as to pass through the cover member.

6. The outboard motor according to claim 5, wherein one end and the other end of the pipe section are attached to the cover member so as to pass through a through hole or notch formed in the cover member.

7. An inlet for the lubricating oil is formed in the upper part of the shift chamber. An outlet for the lubricating oil is formed at the lower end of the shift chamber. The outboard motor according to claim 1, wherein the pipe portion extends from the upper end to the lower end within the shift chamber.

8. An engine cooling passage through which the cooling water for cooling the engine flows, The engine further comprises a water pump provided in the engine cooling passage for circulating the cooling water to the engine, The outboard motor according to claim 1, wherein one end of the pipe section is connected to a portion of the engine cooling passage near the discharge port of the water pump.

9. The outboard motor according to claim 8, wherein the other end of the pipe section is connected to the portion of the engine cooling passage downstream of the engine.

10. The outboard motor according to claim 1, wherein the pipe portion has an inner diameter of approximately 4 mm or more.

11. Hull and The vessel comprises an outboard motor attached to the stern of the hull, The aforementioned outboard motor is Propeller and, The engine serves as the power source for the aforementioned propeller, A drive system component for transmitting the driving force of the engine to the propeller, A shift shaft for switching the shift state, The outboard motor body includes a lower case which contains a shift chamber formed in a cylindrical shape that houses the shift shaft and extends vertically, The shift chamber is configured such that lubricating oil for lubricating the drive system components passes through it. The shift chamber is equipped with a heat exchanger for cooling the lubricating oil, which includes a pipe section through which cooling water circulates. The heat exchanger includes heat transfer fins attached to the pipe section, and is a vessel.

12. The pipe section has a U-shape in which one pair of parts extend vertically from the outboard motor body. The vessel according to claim 11, wherein the heat transfer fins are attached to the pipe portion so as to connect the pair of portions of the pipe portion.

13. The vessel according to claim 12, wherein a plurality of the heat transfer fins are attached to the pipe portion so as to connect the pair of portions of the pipe portion and to be aligned in the vertical direction of the outboard motor body.

14. A cover member is attached to the opening at the upper end of the shift chamber to seal the shift chamber. The vessel according to claim 11, wherein one end and the other end of the pipe section are attached to the cover member.

15. The vessel according to claim 14, wherein one end and the other end of the pipe portion are attached to the cover member so as to pass through the cover member.

16. The vessel according to claim 15, wherein one end and the other end of the pipe portion are attached to the lid member so as to pass through a through hole or notch formed in the lid member.

17. An inlet for the lubricating oil is formed in the upper part of the shift chamber. An outlet for the lubricating oil is formed at the lower end of the shift chamber. The vessel according to claim 11, wherein the pipe portion extends from the upper end to the lower end within the shift chamber.

18. An engine cooling passage through which the cooling water for cooling the engine circulates, The engine further comprises a water pump provided in the engine cooling passage for circulating the cooling water to the engine, The vessel according to claim 11, wherein one end of the pipe section is connected to a portion of the engine cooling passage near the discharge port of the water pump.

19. The vessel according to claim 18, wherein the other end of the pipe section is connected to the portion of the engine cooling passage downstream of the engine.

20. The vessel according to claim 11, wherein the pipe portion has an inner diameter of approximately 4 mm or more.

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