Outboard motors and ships

Abstract

The present invention provides an outboard motor that can efficiently cool the lubricating oil used to lubricate the drive system components while suppressing the complexity of the outboard motor's structure. [Solution] This outboard motor 100 includes a metal lower case 23 that includes a cylindrical shift chamber 30 in which a shift shaft 17 is located. The shift chamber 30 is configured to allow lubricating oil to pass through for lubricating the drive system components PD. The inner circumferential surface 30i of the shift chamber 30 is provided with heat dissipation fins 32 to increase the contact area with the lubricating oil.

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 components to pass through is known (see, for example, Patent Document 1).

[0003] Patent Document 1 describes an outboard motor including drive system components 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) formed in a cylindrical shape so that a shift shaft is accommodated and extends 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 components 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 through which cooling water flows is provided in the lubricating oil storage chamber.

Prior Art Documents

Patent Documents

[0004]

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, a heat exchanger for cooling the lubricating oil is provided, which includes a cooling pipe through which cooling water flows in the lubricating oil storage chamber (shift chamber). Although this allows for efficient cooling of the lubricating oil, the outboard motor also requires structures for connecting the cooling pipe to the inside and outside of the lubricating oil storage chamber, for guiding cooling water from the outside of the outboard motor to one end of the cooling pipe, and for guiding cooling water from the other end of the cooling pipe to the outside of the outboard motor. In other words, the structure of the outboard motor becomes more complex when a heat exchanger including a cooling pipe is provided in the lubricating oil storage chamber. For this reason, there is a need for a configuration that can efficiently cool the lubricating oil for lubricating the drive system components while suppressing the complexity of the outboard motor's structure.

[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 that can efficiently cool the lubricating oil for lubricating the drive system components while suppressing the complexity of the outboard motor's structure. [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 engine's driving force to the propeller, a shift shaft for switching the shift state, and a metal 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 to allow lubricating oil to pass through for lubricating the drive system components, and the inner circumferential surface of the shift chamber is provided with heat dissipation fins to increase the contact area with the lubricating oil.

[0008] In the outboard motor according to the first aspect of this invention, as described above, heat dissipation fins are provided on the inner circumferential surface of the shift chamber to increase the contact area with the lubricating oil. This increases the contact area between the lubricating oil passing through the shift chamber and the shift chamber compared to a case where heat dissipation fins are not provided. This increases the amount of heat dissipated from the lubricating oil passing through the shift chamber to the metal lower case including the shift chamber. Furthermore, when heat dissipation fins are provided on the inner circumferential surface of the shift chamber, unlike a case where a heat exchanger including cooling pipes is provided in the shift chamber, it is not necessary to provide structures for connecting the cooling pipes to the inside and outside of the shift chamber, structures for guiding cooling water from the outside of the outboard motor to one end of the cooling pipes, and structures for guiding cooling water from the other end of the cooling pipes to the outside of the outboard motor. In other words, when heat dissipation fins are provided on the inner circumferential surface of the shift chamber, the structure of the outboard motor is less likely to become complicated compared to a case where a heat exchanger including cooling pipes is provided in the shift chamber. As a result, the lubricating oil for lubricating the drive system components can be efficiently cooled while suppressing the complexity of the outboard motor structure.

[0009] In the outboard motor according to the first aspect described above, preferably, the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from the top to the bottom. With this configuration, compared to the case where the heat dissipation fins are formed only on a portion of the inner circumferential surface of the shift chamber from the top to the bottom, the surface area of ​​the heat dissipation fins can be increased, thereby increasing the contact area between the lubricating oil passing through the shift chamber and the shift chamber. This makes it possible to further increase the amount of heat dissipated from the lubricating oil passing through the shift chamber to the metal lower case containing the shift chamber.

[0010] In the configuration in which the heat dissipation fins are formed on the inner circumferential surface of the shift chamber from top to bottom, preferably, a lubricating oil inlet is formed at the top of the shift chamber, a lubricating oil outlet is formed at the lower end of the shift chamber, and the heat dissipation fins are formed on the inner circumferential surface of the shift chamber from near the lubricating oil outlet to at least near the lubricating oil inlet. With this configuration, since the heat dissipation fins are formed over the entire range in which the lubricating oil passes through the inside of the shift chamber in the vertical direction of the outboard motor body, the contact area between the lubricating oil passing through the shift chamber and the shift chamber can be efficiently increased.

[0011] In the outboard motor according to the first aspect described above, preferably, the heat dissipation fins are provided in multiples on the inner circumferential surface of the shift chamber, not in the center of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body, but arranged on each of the left and right sides of the outboard motor body. With this configuration, the portion of the outboard motor body where the heat dissipation fins are not provided in the center of the outboard motor body in the left-right direction when viewed in the vertical direction can be used as a space for positioning tools so as not to interfere with the heat dissipation fins during the manufacturing of the lower case.

[0012] In the outboard motor according to the first aspect described above, preferably, a shaft through-hole through which the shift shaft passes and a lubricating oil outlet are formed in the bottom surface of the shift chamber, and the heat dissipation fins are provided so as not to overlap with the shaft through-hole and lubricating oil outlet when viewed in the vertical direction of the outboard motor body. With this configuration, since the heat dissipation fins do not overlap with the shaft through-hole and lubricating oil outlet when viewed in the vertical direction of the outboard motor body, for example, when the heat dissipation fins are formed integrally with the lower case, it is possible to suppress interference between the tools used to form the shaft through-hole and lubricating oil outlet and the heat dissipation fins when machining the bottom surface of the shift chamber.

[0013] In the outboard motor according to the first aspect described above, preferably, the heat dissipation fins have a tapered shape that narrows from the root to the tip. With this configuration, when molding the shift chamber on which the heat dissipation fins are provided on the inner circumferential surface, the shift chamber on which the heat dissipation fins are provided on the inner circumferential surface can be easily removed from the mold. This makes it possible to easily mold the shift chamber on which the heat dissipation fins are provided on the inner circumferential surface.

[0014] In the outboard motor according to the first aspect described above, preferably, the heat dissipation fins are integrally formed with the lower case. With this configuration, the number of parts in the outboard motor can be reduced compared to when the heat dissipation fins are formed separately from the lower case.

[0015] In the outboard motor according to the first aspect described above, preferably, the shift chamber is constructed by inserting a cylindrical member into a hole for a cylindrical member formed in the lower case so as to contact the inner circumferential surface of the hole for the cylindrical member, and the heat dissipation fins are provided on the inner circumferential surface of the cylindrical member inserted into the hole for the cylindrical member. With this configuration, a shift chamber with heat dissipation fins provided on its inner circumferential surface can be retrofitted to the lower case by inserting a cylindrical member into a hole for a cylindrical member formed in the lower case. This makes it easy to change the structure (shape, size, arrangement, etc.) of the heat dissipation fins according to the model of the outboard motor, thus improving the design freedom of the heat dissipation fins compared to the case where the heat dissipation fins are integrally formed with the lower case.

[0016] In the configuration in which the shift chamber described above is inserted into a hole for a cylindrical member formed in the lower case so as to contact the inner circumferential surface of the hole for the cylindrical member, preferably the shift chamber is configured such that the cylindrical member is press-fitted into the hole for the cylindrical member so as to contact the inner circumferential surface of the hole for the cylindrical member. With this configuration, the entire inner circumferential surface of the hole for the cylindrical member can be easily brought into contact with the entire outer circumferential surface of the cylindrical member in a heat transfer manner. As a result, even when a shift chamber with heat dissipation fins provided on its inner circumferential surface is retrofitted to the lower case, it is possible to suppress a decrease in the amount of heat dissipated from the shift chamber with heat dissipation fins provided on its inner circumferential surface to the lower case.

[0017] In the outboard motor according to the first aspect described above, preferably, the heat dissipation fins are made of the same type of metal as the lower case. With this configuration, unlike when the heat dissipation fins are made of a different type of metal than the lower case, corrosion of the metals that occurs when different types of metals come into contact can be prevented. Furthermore, when the heat dissipation fins are integrally formed with the lower case, the lower case, including the shift chamber on which the heat dissipation fins are provided on the inner circumferential surface, can be easily integrally molded using a mold, compared to when the heat dissipation fins are made of a different type of metal than the lower case.

[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 engine's driving force to the propeller, a shift shaft for switching the shift state, and a metal lower case including a cylindrical shift chamber in which the shift shaft is located and which extends vertically from the outboard motor body, the shift chamber is configured to allow lubricating oil to pass through for lubricating the drive system components, and the inner circumferential surface of the shift chamber is provided with heat dissipation fins to increase the contact area with the lubricating oil.

[0019] In a vessel according to the second aspect of this invention, as described above, heat dissipation fins are provided on the inner circumferential surface of the shift chamber to increase the contact area with the lubricating oil. This increases the amount of heat dissipated from the lubricating oil passing through the shift chamber to the metal lower case including the shift chamber, similar to the outboard motor according to the first aspect. Also, similar to the outboard motor according to the first aspect, when heat dissipation fins are provided on the inner circumferential surface of the shift chamber, the structure of the outboard motor is less likely to become complicated compared to when a heat exchanger including cooling pipes is provided in the shift chamber. As a result, similar to the outboard motor according to the first aspect, the lubricating oil for lubricating the drive system components can be efficiently cooled while suppressing the complexity of the outboard motor structure.

[0020] In the vessel according to the second aspect described above, preferably, the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from the top to the bottom. With this configuration, similar to the outboard motor according to the first aspect described above, the amount of heat dissipated from the lubricating oil passing through the shift chamber to the metal lower case containing the shift chamber can be increased.

[0021] In the configuration of the ship according to the second aspect described above, where the heat dissipation fins are formed on the inner circumferential surface of the shift chamber from top to bottom, preferably, a lubricating oil inlet is formed at the top of the shift chamber, a lubricating oil outlet is formed at the lower end of the shift chamber, and the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from near the lubricating oil outlet to at least near the lubricating oil inlet. With this configuration, similar to the outboard motor according to the first aspect described above, the contact area between the lubricating oil passing through the shift chamber and the shift chamber can be efficiently increased.

[0022] In the ship according to the second aspect, preferably, the radiator fins are not provided at the central portion in the left - right direction of the outboard motor body when viewed in the up - down direction of the outboard motor body on the inner peripheral surface of the shift chamber, and a plurality of radiator fins are provided side by side on each of the two sides in the left - right direction of the outboard motor body. With this configuration, similar to the outboard motor according to the first aspect, when viewed in the up - down direction of the outboard motor body, the portion where the radiator fins are not provided at the central portion in the left - right direction of the outboard motor body can be used as a space where tools are arranged so as not to interfere with the radiator fins during the manufacture of the lower case.

[0023] In the ship according to the second aspect, preferably, a shaft through - hole through which the shift shaft passes and an outlet of lubricating oil are formed on the bottom surface of the shift chamber, and the radiator fins are provided so as not to overlap with the shaft through - hole and the outlet of lubricating oil when viewed in the up - down direction of the outboard motor body. With this configuration, similar to the outboard motor according to the first aspect, when the radiator fins are integrally formed with the lower case, it is possible to suppress the interference of tools with the radiator fins when performing the processing of forming the shaft through - hole and the outlet of lubricating oil on the bottom surface of the shift chamber.

[0024] In the ship according to the second aspect, preferably, the radiator fins have a tapered shape that tapers from the root portion to the tip portion. With this configuration, similar to the outboard motor according to the first aspect, it is possible to easily mold the shift chamber in which the radiator fins are provided on the inner peripheral surface.

[0025] In the ship according to the second aspect, preferably, the radiator fins are integrally formed with the lower case. With this configuration, similar to the outboard motor according to the first aspect, compared with the case where the radiator fins are formed as a separate body from the lower case, the number of parts of the outboard motor can be reduced.

[0026] In the ship according to the second aspect, preferably, the shift chamber is configured by inserting a cylindrical member into a cylindrical member hole formed in the lower case so that the cylindrical member contacts the inner peripheral surface of the cylindrical member hole, and the heat dissipation fins are provided on the inner peripheral surface of the cylindrical member inserted into the cylindrical member hole. With this configuration, similarly to the outboard motor according to the first aspect, the degree of freedom in designing the heat dissipation fins can be improved as compared with the case where the heat dissipation fins are integrally formed with the lower case.

[0027] In the configuration in which the shift chamber of the ship according to the second aspect is formed in a cylindrical member hole formed in the lower case and the cylindrical member is inserted so as to contact the inner peripheral surface of the cylindrical member hole, preferably, the shift chamber is configured by press-fitting the cylindrical member into the cylindrical member hole so that the cylindrical member contacts the inner peripheral surface of the cylindrical member hole. With this configuration, similarly to the outboard motor according to the first aspect, even when the shift chamber provided with the heat dissipation fins on the inner peripheral surface is retrofitted to the lower case, it is possible to suppress a decrease in the amount of heat dissipation transmitted from the shift chamber provided with the heat dissipation fins on the inner peripheral surface to the lower case.

[0028] In the ship according to the second aspect, preferably, the heat dissipation fins are made of the same type of metal as the lower case. With this configuration, similarly to the outboard motor according to the first aspect, it is possible to prevent metal corrosion that occurs when different types of metals come into contact with each other. Also, similarly to the outboard motor according to the first aspect, when the heat dissipation fins are integrally formed with the lower case, the lower case including the shift chamber provided with the heat dissipation fins on the inner peripheral surface can be easily integrally molded by a mold as compared with the case where the heat dissipation fins are made of a different type of metal from the lower case.

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 cooling lubricating oil for lubricating drive system components while suppressing the complication of the structure of the outboard motor.

Brief Description of the Drawings

[0030] [Figure 1] This is a perspective view of a ship according to a first embodiment of the present invention. [Figure 2] This is a side view of an outboard motor according to a first embodiment of the present invention. [Figure 3] This is a cross-sectional view of the lower case of an outboard motor according to a first embodiment of the present invention. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 3. [Figure 5] This is a cross-sectional view of the lower case of an outboard motor according to a second embodiment of the present invention. [Figure 6] This is a cross-sectional view along the line VI-VI in Figure 5. [Modes for carrying out the invention]

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

[0032] [First Embodiment] An outboard motor 100 and a vessel 120 according to a first embodiment of the present invention will be described with reference to Figures 1 to 4.

[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 30c at the upper end 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 30d is formed in the upper part 30a of the shift chamber 30. A lubricating oil outlet 30f is formed in the bottom surface 30e of the shift chamber 30. That is, a lubricating oil outlet 30f is formed in the lower end 30b of the shift chamber 30. In addition, a shaft through-hole 30g is formed in the bottom surface 30e of the shift chamber 30 through which the shift shaft 17 passes. The shaft through-hole 30g is formed in front of the lubricating oil outlet 30f.

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

[0044] (Configuration of heat dissipation fins) As shown in Figure 4, the inner circumferential surface 30i of the shift chamber 30 is provided with heat dissipation fins 32 to increase the contact area with lubricating oil. The heat dissipation fins 32 have a tapered shape that narrows from the root portion 32a to the tip portion 32b. The heat dissipation fins 32 are made of the same type of metal as the lower case 23. The heat dissipation fins 32 are integrally formed with the lower case 23. Specifically, the lower case 23, which includes the shift chamber 30 with the heat dissipation fins 32 formed on its inner circumferential surface 30i, is molded by casting or the like.

[0045] As shown in Figure 3, the heat dissipation fins 32 are formed on the inner circumferential surface 30i of the shift chamber 30, extending from the upper part 30j to the lower part 30k. Specifically, the heat dissipation fins 32 are formed on the inner circumferential surface 30i of the shift chamber 30, extending from near the lubricating oil outlet 30f to at least near the lubricating oil inlet 30d. Note that Figure 3 shows an example where the heat dissipation fins 32 are formed on the inner circumferential surface 30i of the shift chamber 30, extending from near the lubricating oil outlet 30f to near the cover member 31.

[0046] As shown in Figure 4, the heat dissipation fins 32 are provided in multiple locations on the inner circumferential surface 30i of the shift chamber 30, not in the central part 30h in the left-right direction of the outboard motor body 101 when viewed in the vertical direction of the outboard motor body 101, but rather on each of the left-right sides of the outboard motor body 101. Furthermore, the heat dissipation fins 32 are provided so as not to overlap with the shaft through hole 30g and the lubricating oil outlet 30f when viewed in the vertical direction of the outboard motor body 101. In addition, the heat dissipation fins 32 are provided so as not to overlap with the shift shaft 17 when viewed in the vertical direction of the outboard motor body 101.

[0047] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0048] In the first embodiment, as described above, the inner circumferential surface 30i of the shift chamber 30 is provided with heat dissipation fins 32 to increase the contact area with the lubricating oil. This increases the contact area between the lubricating oil passing through the shift chamber 30 and the shift chamber 30 compared to the case where the heat dissipation fins 32 are not provided. This increases the amount of heat dissipated from the lubricating oil passing through the shift chamber 30 to the metal lower case 23 including the shift chamber 30. Furthermore, when heat dissipation fins 32 are provided on the inner circumferential surface 30i of the shift chamber 30, unlike the case where a heat exchanger including a cooling pipe is provided in the shift chamber 30, it is not necessary to provide in the outboard motor 100 a structure for connecting the cooling pipe to the inside and outside of the shift chamber 30, a structure for guiding cooling water from the outside of the outboard motor 100 to one end of the cooling pipe, or a structure for guiding cooling water from the other end of the cooling pipe to the outside of the outboard motor 100. In other words, when heat dissipation fins 32 are provided on the inner circumferential surface 30i of the shift chamber 30, the structure of the outboard motor 100 is less likely to become complicated compared to when a heat exchanger including cooling pipes is provided in the shift chamber 30. As a result, the lubricating oil for lubricating the drive system components PD can be efficiently cooled while suppressing the complexity of the structure of the outboard motor 100.

[0049] Furthermore, in the first embodiment, as described above, the heat dissipation fins 32 are formed on the inner circumferential surface 30i of the shift chamber 30, extending from the upper part 30j to the lower part 30k. This increases the surface area of ​​the heat dissipation fins 32, compared to the case where the heat dissipation fins 32 are formed only on a portion of the inner circumferential surface 30i of the shift chamber 30, from the upper part 30j to the lower part 30k, thereby increasing the contact area between the lubricating oil passing through the shift chamber 30 and the shift chamber 30. This further increases the amount of heat dissipated from the lubricating oil passing through the shift chamber 30 to the metal lower case 23 containing the shift chamber 30.

[0050] Furthermore, in the first embodiment, as described above, a lubricating oil inlet 30d is formed in the upper part 30a of the shift chamber 30. Also, a lubricating oil outlet 30f is formed in the lower end part 30b of the shift chamber 30. The heat dissipation fins 32 are formed on the inner circumferential surface 30i of the shift chamber 30, extending from near the lubricating oil outlet 30f to at least near the lubricating oil inlet 30d. As a result, the heat dissipation fins 32 are formed over the entire range in which the lubricating oil passes through the inside of the shift chamber 30 in the vertical direction of the outboard motor body 101, so that the contact area between the lubricating oil passing through the shift chamber 30 and the shift chamber 30 can be efficiently increased.

[0051] Furthermore, in the first embodiment, as described above, the heat dissipation fins 32 are not provided in the central part 30h in the left-right direction of the outboard motor body 101 when viewed in the vertical direction of the outboard motor body 101, but rather multiple fins are provided so as to be lined up on each of the left-right sides of the outboard motor body 101. As a result, the portion of the outboard motor body 101 where the heat dissipation fins 32 are not provided in the central part 30h in the left-right direction of the outboard motor body 101 when viewed in the vertical direction of the outboard motor body 101 can be used as a space for positioning tools so as not to interfere with the heat dissipation fins 32 during the manufacturing of the lower case 23.

[0052] Furthermore, in the first embodiment, as described above, a shaft through-hole 30g through which the shift shaft 17 passes, and a lubricating oil outlet 30f are formed in the bottom surface 30e of the shift chamber 30. The heat dissipation fins 32 are provided so as not to overlap with the shaft through-hole 30g and the lubricating oil outlet 30f when viewed in the vertical direction of the outboard motor body 101. As a result, since the heat dissipation fins 32 do not overlap with the shaft through-hole 30g and the lubricating oil outlet 30f when viewed in the vertical direction of the outboard motor body 101, when the heat dissipation fins 32 are integrally formed with the lower case 23, it is possible to suppress interference between the tools used to form the shaft through-hole 30g and the lubricating oil outlet 30f and the heat dissipation fins 32 when machining the bottom surface 30e of the shift chamber 30.

[0053] Furthermore, in the first embodiment, as described above, the heat dissipation fin 32 has a tapered shape that narrows from the root portion 32a to the tip portion 32b. This allows the shift chamber 30, which has the heat dissipation fin 32 on its inner circumferential surface 30i, to be easily removed from the mold when molding the shift chamber 30 on its inner circumferential surface 30i. This makes it easy to mold the shift chamber 30 on its inner circumferential surface 30i.

[0054] Furthermore, in the first embodiment, as described above, the heat dissipation fins 32 are integrally formed with the lower case 23. This reduces the number of parts in the outboard motor 100 compared to the case where the heat dissipation fins 32 are formed separately from the lower case 23.

[0055] Furthermore, in the first embodiment, as described above, the heat dissipation fins 32 are made of the same type of metal as the lower case 23. This prevents metal corrosion that occurs when different types of metals come into contact, unlike when the heat dissipation fins 32 are made of a different type of metal than the lower case 23. Also, when the heat dissipation fins 32 are integrally formed with the lower case 23, the lower case 23, including the shift chamber 30 provided on the inner circumferential surface 30i, can be easily integrally molded using a mold, compared to when the heat dissipation fins 32 are made of a different type of metal than the lower case 23.

[0056] [Second Embodiment] Referring to Figures 5 and 6, the configuration of the outboard motor 200 and the vessel 220 according to the second embodiment of the present invention will be described. In the figures, the same reference numerals are used for parts that are the same as those in the first embodiment described above.

[0057] (Ship composition) As shown in Figure 5, the vessel 220 is equipped with an outboard motor 200.

[0058] (Outboard motor configuration) As shown in Figure 5, the outboard motor 200 includes an outboard motor body 201. The outboard motor body 201 includes a lower case 223. The lower case 223 includes a shift chamber 230.

[0059] (Shift room configuration) As shown in Figure 5, the shift chamber 230 is constructed by press-fitting a cylindrical member 240 into a cylindrical member hole 223e formed in the lower case 223 so as to contact the inner circumferential surface 223f of the cylindrical member hole 223e.

[0060] (Configuration of heat dissipation fins) As shown in Figure 6, the inner circumferential surface 230i of the shift chamber 230 is provided with heat dissipation fins 232 to increase the contact area with lubricating oil. The heat dissipation fins 232 are provided on the inner circumferential surface 240a of the cylindrical member 240 (the inner circumferential surface 230i of the shift chamber 230) which is inserted into the hole 223e for the cylindrical member.

[0061] The other configurations of the second embodiment are the same as those of the first embodiment described above.

[0062] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0063] In the second embodiment, as described above, the inner circumferential surface 230i of the shift chamber 230 is provided with heat dissipation fins 232 to increase the contact area with the lubricating oil. This increases the amount of heat dissipated from the lubricating oil passing through the shift chamber 230 to the metal lower case 223 which includes the shift chamber 230, similar to the first embodiment. Also, similar to the first embodiment, when heat dissipation fins 232 are provided on the inner circumferential surface 230i of the shift chamber 230, the structure of the outboard motor 200 is less complicated compared to when a heat exchanger including cooling pipes is provided in the shift chamber. As a result, similar to the first embodiment, the lubricating oil for lubricating the drive system components PD can be efficiently cooled while suppressing the complexity of the structure of the outboard motor 200.

[0064] Furthermore, in the second embodiment, as described above, the shift chamber 230 is configured by inserting a cylindrical member 240 into a cylindrical member hole 223e formed in the lower case 223 so as to contact the inner circumferential surface 223f of the cylindrical member hole 223e. The heat dissipation fins 32 are provided on the inner circumferential surface 240a of the cylindrical member 240 inserted into the cylindrical member hole 223e. As a result, by inserting the cylindrical member 240 into the cylindrical member hole 223e formed in the lower case 223, a shift chamber 230 with heat dissipation fins 232 provided on its inner circumferential surface 232i can be retrofitted to the lower case 223. This makes it easy to change the structure (shape, size, arrangement, etc.) of the heat dissipation fins 232 according to the model of the outboard motor 200, thus improving the design freedom of the heat dissipation fins 232 compared to the case where the heat dissipation fins 232 are integrally formed with the lower case 223.

[0065] Furthermore, in the second embodiment, as described above, the shift chamber 230 is configured such that a cylindrical member 240 is press-fitted into the cylindrical member hole 223e so as to contact the inner circumferential surface 223f of the cylindrical member hole 223e. This allows the entire inner circumferential surface 223f of the cylindrical member hole 223e to easily come into contact with the entire outer circumferential surface of the cylindrical member 240, enabling heat transfer. As a result, even when a shift chamber 230 with heat dissipation fins 232 provided on its inner circumferential surface 232i is retrofitted to the lower case 223, it is possible to suppress a decrease in the amount of heat dissipated from the shift chamber 230 with heat dissipation fins 232 on its inner circumferential surface 232i to the lower case 223.

[0066] Furthermore, the other effects of the second embodiment are the same as those of the first embodiment described above.

[0067] [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 (exceptions) within the meaning and scope of the claims.

[0068] For example, in the first and second embodiments described above, the heat dissipation fins 32 (232) are shown to be made of the same type of metal as the lower case 23 (232), but the present invention is not limited thereto. In the present invention, the heat dissipation fins may be made of a different type of metal than the lower case.

[0069] Furthermore, in the second embodiment described above, an example was shown in which the shift chamber 230 is configured by press-fitting a cylindrical member 240 into a cylindrical member hole 223e so as to contact the inner circumferential surface 223f of the cylindrical member hole 223e, but the present invention is not limited thereto. In the present invention, the shift chamber may be configured by inserting a cylindrical member into a cylindrical member hole by a method other than press-fitting so as to contact the inner circumferential surface of the cylindrical member hole.

[0070] Furthermore, while the first and second embodiments described above show examples in which the heat dissipation fin 32(232) has a tapered shape that narrows from the base portion 32a to the tip portion 32b, the present invention is not limited thereto. In the present invention, the heat dissipation fin may have a shape other than a tapered shape that narrows from the base portion to the tip portion.

[0071] Furthermore, in the first and second embodiments described above, examples were shown in which the heat dissipation fins 32 (232) are provided so as not to overlap with the shaft through-hole 30g and the lubricating oil outlet 30f when viewed in the vertical direction of the outboard motor body 101 (201), but the present invention is not limited thereto. In the present invention, the heat dissipation fins may be provided so as to overlap with the shaft through-hole or so as to overlap with the lubricating oil outlet when viewed in the vertical direction of the outboard motor body.

[0072] Furthermore, in the first and second embodiments described above, the heat dissipation fins 32(232) are not provided in the central part 30h of the outboard motor body 101(201) in the left-right direction when viewed in the vertical direction of the outboard motor body 101(201), but rather in multiple locations arranged on each of the left-right sides of the outboard motor body 101(201). However, the present invention is not limited to this. In the present invention, the heat dissipation fins may be provided on the inner surface of the shift chamber, on only one side of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body. Alternatively, the heat dissipation fins may be provided on the inner surface of the shift chamber, on the central part of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body. Furthermore, the heat dissipation fins may be located in the center of the outboard motor body in the left-right direction, rather than being located on both sides of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body, on the inner circumferential surface of the shift chamber.

[0073] Furthermore, while the first and second embodiments described above show examples in which the heat dissipation fins 32 (232) are formed on the inner circumferential surface 30i (230i) of the shift chamber 30 (230) from near the lubricating oil outlet 30f to at least near the lubricating oil inlet 30d, the present invention is not limited thereto. In the present invention, the heat dissipation fins may be formed on only a portion of the inner circumferential surface of the shift chamber, from near the lubricating oil outlet to at least near the lubricating oil inlet.

[0074] Furthermore, while the first and second embodiments described above show examples in which the heat dissipation fins 32(232) are formed on the inner circumferential surface 30i(230i) of the shift chamber 30(230) from the upper part 30j to the lower part 30k, the present invention is not limited thereto. In the present invention, the heat dissipation fins may be formed only on a portion of the inner circumferential surface of the shift chamber, from the upper part to the lower part.

[0075] Furthermore, while the first and second embodiments described above show examples in which the shaft through-hole 30g is formed in front of the lubricating oil outlet 30f, the present invention is not limited thereto. 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.

[0076] Furthermore, in the first and second embodiments described above, examples were shown in which the lubricating oil outlet 30f and the shaft through-hole 30g are formed so as to be aligned in the front-rear direction of the outboard motor body 101 on the bottom surface 30e of the shift chamber 30, but the present invention is not limited thereto. 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.

[0077] Furthermore, although the first and second embodiments described above show an example in which only one outboard motor 100 (200) is attached to the stern 111 of the hull 110, the present invention is not limited thereto. In the present invention, multiple outboard motors may be attached to the stern of the hull. [Explanation of Symbols]

[0078] 11 Engine 12 propellers 17 Shift shaft 23(223) Lower Case 30(230) Shift Room 30a Upper part (of the shift room) 30b Lower end (of the shift room) 30d Lubricant inlet 30e (Shift room) bottom 30f Lubricant outlet 30g shaft through hole 30h (Central part of the outboard motor body in the left-right direction on the inner circumference of the shift chamber) 30i (230i) Inner surface (of the shift compartment) 30j (upper part of the inner circumference of the shift chamber) 30k (Lower part of the inner circumference of the shift chamber) 32 (232) heat dissipation fins 32a Base (of the heat sink fin) 32b Tip (of the heat sink fin) 100 (200) Outboard motor 101 (201) Outboard motor body 110 hull 111 Stern 120(220) Ship 223e Hole for cylindrical member 223f (Inner circumferential surface of hole for cylindrical member) 240 Cylindrical member 240a Inner surface (of the cylindrical member) PD drive system components

Claims

1. Propeller and, The engine that is the power source for the 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 metal 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. An outboard motor, wherein the inner circumferential surface of the shift chamber is provided with heat dissipation fins to increase the contact area with the lubricating oil.

2. The outboard motor according to claim 1, wherein the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from the top to the bottom.

3. 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 2, wherein the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending at least from the vicinity of the lubricating oil outlet to the vicinity of the lubricating oil inlet.

4. The outboard motor according to claim 1, wherein the heat dissipation fins are provided in multiples on the inner circumferential surface of the shift chamber, not in the center of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body, but arranged on each of the left and right sides of the outboard motor body.

5. The bottom surface of the shift chamber has a shaft through-hole through which the shift shaft passes, and an outlet for the lubricating oil. The outboard motor according to claim 1, wherein the heat dissipation fins are provided so as not to overlap with the shaft through hole and the lubricating oil outlet when viewed in the vertical direction of the outboard motor body.

6. The outboard motor according to claim 1, wherein the heat dissipation fin has a tapered shape that narrows from the base to the tip.

7. The outboard motor according to claim 1, wherein the heat dissipation fins are integrally formed with the lower case.

8. The shift chamber is constructed by inserting a cylindrical member into a hole for a cylindrical member formed in the lower case so as to contact the inner circumferential surface of the hole for the cylindrical member. The outboard motor according to claim 1, wherein the heat dissipation fins are provided on the inner circumferential surface of the cylindrical member inserted into the hole for the cylindrical member.

9. The outboard motor according to claim 8, wherein the shift chamber is configured such that the cylindrical member is inserted into the hole for the cylindrical member by press-fitting so as to contact the inner circumferential surface of the hole for the cylindrical member.

10. The outboard motor according to claim 1, wherein the heat dissipation fins are made of the same type of metal as the lower case.

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 metal 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. A ship, wherein the inner circumferential surface of the shift chamber is provided with heat dissipation fins to increase the contact area with the lubricating oil.

12. The ship according to claim 11, wherein the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from the top to the bottom.

13. 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 12, wherein the heat dissipation fins are formed on the inner circumferential surface of the shift chamber, extending from near the outlet of the lubricating oil to at least near the inlet of the lubricating oil.

14. The vessel according to claim 11, wherein the heat dissipation fins are provided in multiples on the inner circumferential surface of the shift chamber, not in the center of the outboard motor body in the left-right direction when viewed in the vertical direction of the outboard motor body, but arranged on each of the left and right sides of the outboard motor body.

15. The bottom surface of the shift chamber has a shaft through-hole through which the shift shaft passes, and an outlet for the lubricating oil. The vessel according to claim 11, wherein the heat dissipation fins are provided so as not to overlap with the shaft through-hole and the lubricating oil outlet when viewed in the vertical direction of the outboard motor body.

16. The ship according to claim 11, wherein the heat dissipation fin has a tapered shape that narrows from the base to the tip.

17. The ship according to claim 11, wherein the heat dissipation fins are integrally formed with the lower case.

18. The shift chamber is constructed by inserting a cylindrical member into a hole for a cylindrical member formed in the lower case so as to contact the inner circumferential surface of the hole for the cylindrical member. The ship according to claim 11, wherein the heat dissipation fins are provided on the inner circumferential surface of the cylindrical member inserted into the hole for the cylindrical member.

19. The ship according to claim 18, wherein the shift chamber is configured such that the cylindrical member is inserted into the hole for the cylindrical member by press-fitting so as to contact the inner circumferential surface of the hole for the cylindrical member.

20. The ship according to claim 11, wherein the heat dissipation fins are made of the same type of metal as the lower case.

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