Outboard motor and drive shaft assembly method

Abstract

To assemble a drive shaft and a drive gear in a lower case even when the drive gear is formed integrally with the drive shaft.SOLUTION: In a lower gear chamber 15 of a lower case 11 of an outboard engine, a gear position setting member 67 for setting a position of a front driven gear 47 in a cross direction is provided before the front driven gear 47, and a screw mechanism for moving the gear position setting member 67 in the cross direction when the gear position setting member 67 is rotated about its axis A is provided in a setting member disposing hole 61 and the gear position setting member 67. When a lower drive shaft 38 with which a main drive gear 46 is integrally formed is assembled in the lower case 11, the gear position setting member 67 is rotated to be moved forward. Thus, the front driven gear 47 is moved forward, and a free region located below a drive shaft disposing hole 16 is expanded in the lower gear chamber 15.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an outboard motor and a drive shaft assembling method for assembling a drive shaft integrally formed with a drive gear to a lower case of the outboard motor. [Background technology]

[0002] Many outboard motors are equipped with a power source located on top of the outboard motor, a drive shaft extending downward from the power source, a propeller shaft located on the bottom of the outboard motor and extending in the fore-and-aft direction, a propeller attached to the propeller shaft, and a gear mechanism located on the bottom of the outboard motor that transmits rotation of the drive shaft to the propeller shaft.

[0003] In such an outboard motor, the gear mechanism and other components are disposed in a lower case provided at the bottom of the outboard motor. Specifically, a gear chamber is provided in the lower case, and the gear mechanism is housed in the gear chamber. A drive shaft mounting hole is provided in the lower case, communicating with the gear chamber from above, and a drive shaft is disposed in the drive shaft mounting hole. A propeller shaft mounting hole is provided in the lower case, communicating with the gear chamber from behind, and a propeller shaft is disposed in the propeller shaft mounting hole.

[0004] The gear mechanism also has a drive gear coupled to the lower end of the drive shaft and a driven gear coupled to the front end of the propeller shaft. Bevel gears are used as both the drive gear and the driven gear to transmit rotation from the drive shaft, which extends vertically, to the propeller shaft, which extends longitudinally. Many outboard motor gear mechanisms have two driven gears. That is, the gear mechanism of a contra-rotating propeller-type outboard motor is provided with two driven gears to transmit rotation from the drive shaft to each of the two propeller shafts. Even in outboard motors with a single propeller shaft, the gear mechanism often has two driven gears to enable a clutch to switch the direction of rotation transmitted from the drive shaft to the propeller shaft. Furthermore, in both the gear mechanism of an outboard motor with contra-rotating propellers and that of an outboard motor with a single propeller shaft, one of the two driven gears is located in front of the drive gear and meshes with the drive gear from the front, and the other driven gear is located behind the drive gear and meshes with the drive gear from the rear.

[0005] In a conventional contra-rotating propeller outboard motor having such a configuration, the drive shaft and drive gear are formed separately, and the drive gear is fitted to the lower end of the drive shaft. The propeller shaft and driven gear are also formed separately, and the driven gear is fitted to the front end of the propeller shaft. Even in a conventional outboard motor having the above configuration that has a single propeller shaft, the drive shaft and drive gear are formed separately, and the drive gear is fitted to the lower end of the drive shaft. In an outboard motor with a single propeller shaft, each driven gear is connected to the propeller shaft via a clutch, and due to this structure, the driven gear and the propeller shaft are formed separately.

[0006] A conventional contra-rotating propeller outboard motor (1) shown in Figure 2 of Patent Document 1 below includes a pinion gear (18) and a lower drive shaft (172). The pinion gear (18) corresponds to a drive gear, and the lower drive shaft (172) corresponds to a drive shaft. In the outboard motor (1), the lower drive shaft (172) and the pinion gear (18) are formed separately, and the pinion gear (18) is fitted to the lower drive shaft (172). The outboard motor (1) also includes a front gear (21), a rear gear (22), an inner shaft (231), and an outer shaft (232). The front gear (21) and the rear gear (22) correspond to driven gears, and the inner shaft (231) and the outer shaft (232) correspond to propeller shafts. In the outboard motor 1, the inner shaft 231 and the front gear 21 are formed separately, and the front gear 21 is fitted to the inner shaft 231. The outer shaft 232 and the rear gear 22 are formed separately, and the rear gear 22 is fitted to the outer shaft 232. The reference numerals in parentheses are those described in Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-94116 Summary of the Invention [Problem to be solved by the invention]

[0008] In the conventional outboard motor described above, the drive shaft and drive gear are formed separately, and the drive gear is fitted to the lower end of the drive shaft. However, when the torque of the power source is increased, a structure in which the drive gear is fitted to the drive shaft can make it difficult to stabilize the transmission of power from the power source from the drive shaft to the propeller shaft. Therefore, it has been considered to form the drive gear integrally with the drive shaft. By forming the drive gear integrally with the drive shaft, the connection strength between the drive shaft and the drive gear can be increased, thereby improving the stability of power transmission from the drive shaft to the propeller shaft.

[0009] However, when the drive gear is integrally formed with the drive shaft, there is a problem in that it becomes difficult to assemble the drive shaft and the drive gear into the lower case.

[0010] For example, in the conventional contra-rotating propeller outboard motor described above, the work of assembling the drive shaft, two propeller shafts, drive gear, and two driven gears into the lower case is generally carried out as follows: First, of the two driven gears, the driven gear located in front of the drive gear (hereinafter referred to as the "front driven gear") is inserted into the gear chamber from the rear of the lower case through the propeller shaft mounting hole and attached to the gear chamber. Next, the drive gear is inserted into the gear chamber from the rear of the lower case through the propeller shaft mounting hole, and the drive shaft is passed through the drive shaft mounting hole from above the lower case. Within the gear chamber, the drive gear is fitted onto the lower end of the drive shaft while meshing with the front driven gear, and the drive shaft is then attached to the drive shaft mounting hole. Next, the driven gear disposed behind the drive gear and the two propeller shafts are inserted into the propeller shaft arrangement hole from the rear of the lower case, and these are assembled into the gear chamber or the propeller shaft arrangement hole.

[0011] When the drive gear is integrally formed with the drive shaft, the drive shaft with the integral drive gear must be assembled into the lower case. There are two possible methods for assembling the drive shaft with the integral drive gear into the lower case:

[0012] The first method is to insert the drive shaft 122, which is integrally formed with the drive gear 121, into the drive shaft arrangement hole 126 from above the lower case 123, place the drive gear 121 in the gear chamber 125, and attach the drive shaft 122 to the drive shaft arrangement hole 126, as shown in Figure 10(A).

[0013] The second method is to insert the drive shaft 122, which is integrally formed with the drive gear 121, from the rear of the lower case 123 through the propeller shaft arrangement hole 124 into the gear chamber 125, and then insert the drive shaft 122 into the drive shaft arrangement hole 126 from below and attach it to the drive shaft arrangement hole 126, as shown in Figure 10(B).

[0014] However, the first method is difficult to adopt for the following reason. Specifically, as can be seen from FIG. 10(A), the diameter of the drive shaft mounting hole 126 is smaller than the diameter of the drive gear 121, so the drive gear 121 cannot be inserted into the drive shaft mounting hole 126. Therefore, with the first method, the drive shaft 122 integrally formed with the drive gear 121 cannot be assembled into the lower case 123. By making the diameter of the drive shaft mounting hole 126 larger than the diameter of the drive gear 121, the drive shaft 122 integrally formed with the drive gear 121 can be assembled into the lower case 123. However, if the diameter of the drive shaft mounting hole 126 is made larger than the diameter of the drive gear 121, the width of the lower case 123 increases, resulting in increased water resistance during navigation. Therefore, it is not preferable to make the diameter of the drive shaft mounting hole 126 larger than the diameter of the drive gear 121.

[0015] 10(B), it is necessary to install the front driven gear 127 in the gear chamber 125 before inserting the drive shaft 122, which is integrally formed with the drive gear 121, into the propeller shaft arrangement hole 124. With the front driven gear 127 installed in the gear chamber 125, the front driven gear 127 gets in the way, making it impossible to insert the drive shaft 122, which is integrally formed with the drive gear 121, into the drive shaft arrangement hole 126 from below.

[0016] The present invention has been made in consideration of the problems described above, and an object of the present invention is to provide an outboard motor and a drive shaft assembly method that allows the drive shaft and drive gear to be assembled into the lower case even when the drive gear is integrally formed with the drive shaft. [Means for solving the problem]

[0017] In order to solve the above problems, an outboard motor of the present invention includes a case having a gear chamber, a drive shaft mounting hole communicating with the gear chamber from above the gear chamber, and a propeller shaft mounting hole communicating with the gear chamber from behind the gear chamber; a drive shaft extending in the up-down direction and mounted in the drive shaft mounting hole; a propeller shaft extending in the front-rear direction and mounted in the propeller shaft mounting hole; a drive gear which is a bevel gear connected to the lower end of the drive shaft and mounted in the gear chamber; and a bevel gear which is connected to the front end of the propeller shaft and mounted in the gear chamber. a driven gear disposed in front of the drive gear in the case and meshing with the drive gear; a gear position setting member provided in front of the driven gear in the case and setting the position of the driven gear in the front-rear direction; and a screw mechanism that moves the gear position setting member in the front-rear direction when the gear position setting member is rotated around an axis of the gear position setting member extending in the front-rear direction, the screw mechanism comprising a first screw provided in the case and having an axis extending in the front-rear direction, and a second screw provided in the gear position setting member and having an axis extending in the front-rear direction and threadedly engaged with the first screw. The gear position setting member moves the driven gear forward from a set position where the driven gear meshes with the drive gear, thereby expanding the free space in the gear chamber so that the drive shaft coupled to the drive gear can be inserted into the drive shaft arrangement hole through the propeller shaft arrangement hole and the gear chamber, and on the other hand, moves the driven gear to the set position, thereby meshing the driven gear with the drive gear. It is characterized by:

[0018] In order to solve the above-mentioned problems, the drive shaft assembling method of the present invention includes a case having a gear chamber, a drive shaft arranging hole communicating with the gear chamber from above the gear chamber, and a propeller shaft arranging hole communicating with the gear chamber from behind the gear chamber, a drive shaft extending in the up-down direction and arranged in the drive shaft arranging hole, a propeller shaft extending in the front-rear direction and arranged in the propeller shaft arranging hole, a drive gear which is a bevel gear formed integrally with the drive shaft at a lower end side of the drive shaft and arranged in the gear chamber, and a bevel gear which is coupled to a front end side of the propeller shaft and arranged in the gear chamber. a gear position setting member provided in front of the driven gear in the case and configured to set the position of the driven gear in the fore-and-aft direction; and a screw mechanism that moves the gear position setting member in the fore-and-aft direction when the gear position setting member is rotated about an axis of the gear position setting member extending in the fore-and-aft direction. A drive shaft assembling method for assembling the drive shaft, which is integrally formed with the drive gear, into the case includes the steps of: positioning the driven gear in front of a set position where the driven gear is to mesh with the drive gear; arrangement The drive shaft is inserted into the gear chamber through the hole, and then the drive shaft is inserted from the gear chamber to the drive shaft. arrangement a drive shaft inserting step for inserting the drive shaft into a hole; and a tool for rotating the gear position setting member into the propeller shaft. arrangement The method is characterized by comprising a tool attachment process in which the tool is inserted into the gear chamber through a hole and attached to the gear position setting member, and a driven gear moving process in which the gear position setting member is rotated with the tool, and the driven gear is moved to the set position and meshed with the drive gear. [Effects of the Invention]

[0019] According to the present invention, even if the drive gear is integrally formed with the drive shaft, the drive shaft and the drive gear can be assembled inside the lower case. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an overall view showing an outboard motor according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view showing the inside of a lower portion of the outboard motor according to the embodiment of the present invention. [Figure 3] 3 is an enlarged cross-sectional view showing an upper gear mechanism, a clutch, etc. in FIG. 2. [Figure 4] 3 is an enlarged cross-sectional view showing a lower gear mechanism and the like in FIG. 2. FIG. [Figure 5] FIG. 2 is a cross-sectional view showing a lower gear chamber in the outboard motor according to the embodiment of the present invention. [Figure 6] FIG. 2 is an explanatory diagram showing a gear position setting member of the outboard motor according to the embodiment of the present invention as viewed from the front. [Figure 7] 7(A) is an explanatory diagram showing the gear position setting member in FIG. 6 as seen from the left, and FIG. 7(B) is an explanatory diagram showing a cross section of the gear position setting member and a tool taken along section line VII-VII in FIG. 6. [Figure 8] 10A to 10C are explanatory diagrams showing a drive shaft assembly process in the embodiment of the present invention. [Figure 9] 10A and 10B are explanatory views showing another embodiment of the screw mechanism and tool mounting portion of the outboard motor of the present invention. [Figure 10] 10 is an explanatory diagram illustrating the difficulty of assembling a drive shaft integrally formed with a drive gear into a lower case in a conventional outboard motor. DETAILED DESCRIPTION OF THE INVENTION

[0021] An outboard motor according to an embodiment of the present invention includes a case having a gear chamber, a drive shaft mounting hole communicating with the gear chamber from above the gear chamber, and a propeller shaft mounting hole communicating with the gear chamber from behind the gear chamber; a drive shaft extending in the up-down direction and disposed in the drive shaft mounting hole; and a propeller shaft extending in the front-rear direction and disposed in the propeller shaft mounting hole. The outboard motor according to an embodiment of the present invention also includes a drive gear and a driven gear. The drive gear is a bevel gear coupled to the lower end of the drive shaft and disposed within the gear chamber. The driven gear is also a bevel gear coupled to the front end of the propeller shaft and disposed in front of the drive gear within the gear chamber, meshing with the drive gear. The outboard motor according to an embodiment of the present invention also includes a gear position setting member and a screw mechanism. The gear position setting member is disposed in front of the driven gear within the case and sets the front-rear position of the driven gear. The screw mechanism is a mechanism that moves the gear position setting member in the front-to-rear direction when the gear position setting member is rotated about an axis of the gear position setting member that extends in the front-to-rear direction. The screw mechanism also includes a first screw that is provided on the case and has an axis that extends in the front-to-rear direction, and a second screw that is provided on the gear position setting member and has an axis that extends in the front-to-rear direction and is threadedly engaged with the first screw.

[0022] According to the outboard motor of this embodiment, even if the drive gear is integrally formed with the drive shaft, the drive shaft can be assembled within the case. Specifically, by rotating the gear position setting member about its axis and moving the gear position setting member forward, the driven gear disposed within the gear chamber can be moved forward. Moving the driven gear forward moves the driven gear away from the opening of the drive shaft mounting hole, which is connected to the gear chamber, thereby expanding the free space within the gear chamber below the drive shaft mounting hole. Therefore, after moving the driven gear forward, the drive shaft integrally formed with the drive gear can be inserted into the gear chamber from the rear of the case through the propeller shaft mounting hole, and then inserted into the drive shaft mounting hole from below and attached to it. The gear position setting member is then rotated in the opposite direction to move the driven gear rearward together with the gear position setting member, thereby allowing the driven gear to mesh with the drive gear.

[0023] A drive shaft assembling method according to an embodiment of the present invention is a method for assembling a drive shaft integrally formed with a drive gear into a case in an outboard motor according to the embodiment of the present invention, in which the drive gear is integrally formed with the drive shaft at the lower end of the drive shaft. The drive shaft assembling method according to an embodiment of the present invention includes the steps of: positioning the driven gear forward of the position at which the driven gear meshes with the drive gear; arrangement The drive shaft is inserted into the gear chamber through the hole, and then the drive shaft is inserted from the gear chamber into the drive shaft. arrangement A drive shaft insertion process is performed to insert the drive shaft into the hole, and a tool for rotating the gear position setting member is inserted into the propeller shaft. arrangement The drive shaft assembling method of this embodiment includes a tool attachment step of inserting a tool into the gear chamber through the hole and attaching the tool to the gear position setting member, and a driven gear moving step of rotating the gear position setting member with the tool to move the driven gear to the set position and mesh with the drive gear. According to the drive shaft assembling method of this embodiment, the drive shaft integrally formed with the drive gear can be easily assembled into the case. [Example]

[0024] An embodiment of an outboard motor of the present invention will be described. In the embodiment, directions such as up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd) are indicated by arrows drawn at the bottom right of Figures 1 to 8.

[0025] (Outboard motor) FIG. 1 shows an outboard motor 1 according to an embodiment of the present invention. As shown in FIG. 1, the outboard motor 1 is a contra-rotating propeller outboard motor. The outboard motor 1 includes an engine 2 as a power source, a front propeller 3, an outer propeller shaft 4 to which the front propeller 3 is attached, a rear propeller 5, an inner propeller shaft 6 to which the rear propeller 5 is attached, and a power transmission mechanism 7 that transmits power from the engine 2 to the propeller shafts 4, 6. The engine 2 is located at the top of the outboard motor 1, and the propeller shafts 4, 6 are located at the bottom of the outboard motor 1. The power transmission mechanism 7 is located between the engine 2 and the propeller shafts 4, 6. The power transmission mechanism 7 also includes an upper drive shaft 21, an upper gear mechanism 22, a clutch 27, an intermediate drive shaft 35, a connecting member 36, a lower drive shaft 38, and a lower gear mechanism 45.

[0026] The engine 2 is covered by a bottom cowl 8 and a top cowl 9. The upper drive shaft 21 is disposed within an upper case 10. The upper gear mechanism 22, clutch 27, intermediate drive shaft 35, connecting member 36, lower drive shaft 38, and lower gear mechanism 45 are disposed within a lower case 11 provided at the bottom of the outboard motor 1. The front end portions of the outer propeller shaft 4 and the inner propeller shaft 6 are disposed within the lower case 11. The lower case 11 is a specific example of a "case," and the lower drive shaft 38 is a specific example of a "drive shaft." The outer propeller shaft 4 and the inner propeller shaft 6 are each a specific example of a "propeller shaft."

[0027] (Lower case) 2 shows a cross section of components provided in the lower part of the outboard motor 1, viewed from the left, taken along a plane extending in the front-to-rear and up-to-down directions and including the axes of the drive shafts 21, 35, 38 and the propeller shafts 4, 6. In FIG. 2, the lower case 11 is formed in a roughly box-like shape with an open top, and a cover member 12 is provided on the top of the lower case 11 to cover part of the top of the lower case 11. A drive shaft insertion hole 13 is also formed in the cover member 12.

[0028] An upper gear chamber 14 is provided in the upper front portion of the lower case 11. The drive shaft insertion hole 13 is in communication with the upper gear chamber 14. A lower gear chamber 15 is provided in the lower front portion of the lower case 11. A drive shaft arrangement hole 16 is formed between the upper gear chamber 14 and the lower gear chamber 15 in the lower case 11, connecting the two chambers. The drive shaft arrangement hole 16 extends in the vertical direction and is in communication with the lower gear chamber 15 from above. A propeller shaft arrangement hole 17 is formed in the lower case 11 behind the lower gear chamber 15. The propeller shaft arrangement hole 17 extends in the front-rear direction and is in communication with the lower gear chamber 15 from behind. The lower gear chamber 15 is a specific example of a "gear chamber."

[0029] (Upper drive shaft) As shown in Fig. 1, the upper drive shaft 21 extends in the vertical direction, and its upper end is connected to the engine 2. Furthermore, as shown in Fig. 2, the lower end of the upper drive shaft 21 is inserted into the drive shaft insertion hole 13. The upper drive shaft 21 rotates in one direction by the power of the engine 2. The rotation direction of the upper drive shaft 21 is defined as the forward direction.

[0030] (Upper gear mechanism, clutch) 3 is an enlarged view of the upper gear mechanism 22, the clutch 27, and the like in FIG. 2. The upper gear mechanism 22 is a mechanism that generates rotation in the opposite direction to the rotation of the upper drive shaft 21. The upper gear mechanism 22 is disposed in the upper gear chamber 14. As shown in FIG. 3, the upper gear mechanism 22 includes a reverse drive gear 23, a reverse intermediate gear 24, and a reverse output gear 25.

[0031] The reverse drive gear 23 is a bevel gear that is disposed in the upper part of the upper gear chamber 14 with the toothed portion facing downward, and is rotatably supported by the cover member 12 via a bearing. The reverse drive gear 23 is also spline-coupled (fitted) to the lower end of the upper drive shaft 21, for example, and rotates integrally with the upper drive shaft 21.

[0032] The reverse intermediate gear 24 is a bevel gear and is disposed in the front part of the upper gear chamber 14 so that the part on which the teeth are formed faces backward. A shaft is integrally formed with the reverse intermediate gear 24, and the shaft of the reverse intermediate gear 24 is rotatably supported by the lower case 11 via a bearing.

[0033] The reverse output gear 25 is a bevel gear that is disposed in the lower part of the upper gear chamber 14 with its teeth facing upward, and is rotatably supported by the lower case 11 via a bearing. A through hole 26 is formed in the center of the reverse output gear 25. The upper end portion of the intermediate drive shaft 35 is inserted into the through hole 26, but the through hole 26 and the upper end portion of the intermediate drive shaft 35 are spaced apart from each other.

[0034] The reverse drive gear 23 meshes with a reverse intermediate gear 24, and the reverse intermediate gear 24 meshes with a reverse output gear 25. When the reverse drive gear 23 rotates in the forward direction, the rotation is transmitted to the reverse output gear 25 via the reverse intermediate gear 24, causing the reverse output gear 25 to rotate in the reverse direction.

[0035] The clutch 27 is a dog clutch formed in a cylindrical shape with clutch pawls 28 formed on each of its upper and lower end surfaces. Grooves 29 are formed around the entire outer periphery of the clutch 27. The clutch 27 is disposed between the reverse drive gear 23 and the reverse output gear 25. Within the upper gear chamber 14, the upper end portion of the intermediate drive shaft 35 passes through a through-hole 26 in the reverse output gear 25 and enters between the reverse drive gear 23 and the reverse output gear 25. The clutch 27 is coupled to the upper end portion of the intermediate drive shaft 35 so as to be immovable in the circumferential direction relative to the intermediate drive shaft 35 but movable in the axial direction. As a result, the clutch 27 and the intermediate drive shaft 35 rotate integrally, but the clutch 27 can move up and down relative to the intermediate drive shaft 35.

[0036] A shift member 30 and a clutch control unit 31 are also provided within the lower case 11. One end of the shift member 30 is inserted into a groove 29 of the clutch 27 so that the clutch 27 is rotatable relative to the shift member 30. The other end of the shift member 30 is connected to an actuator (not shown) provided in the clutch control unit 31. By operating this actuator, the shift member 30 can be moved up and down, thereby moving the clutch 27 up and down. When the clutch 27 moves up, a clutch pawl 28 formed on the upper end surface of the clutch 27 engages with a clutch pawl 32 formed on the lower end surface of the reverse drive gear 23. This directly transmits the rotation of the upper drive shaft 21 to the intermediate drive shaft 35, causing the intermediate drive shaft 35 to rotate in the forward direction. On the other hand, when the clutch 27 moves down, a clutch pawl 28 formed on the lower end surface of the clutch 27 engages with a clutch pawl 33 formed on the upper end surface of the reverse output gear 25. As a result, the rotation of the reverse output gear 25 is transmitted to the intermediate drive shaft 35, causing the intermediate drive shaft 35 to rotate in the reverse direction.

[0037] (Intermediate drive shaft, connecting member) The intermediate drive shaft 35 extends vertically, is located below the upper drive shaft 21, and is coaxial with the upper drive shaft 21. The upper end of the intermediate drive shaft 35 is coupled to the clutch 27 as described above. The lower end of the intermediate drive shaft 35 is connected to the lower drive shaft 38 via a connecting member 36. The connecting member 36 is cylindrical and has a spline formed on its inner circumferential surface. The outer circumferential surface of the lower end of the intermediate drive shaft 35 is also splined, and the outer circumferential surface of the upper end of the lower drive shaft 38 is also splined. The lower end of the intermediate drive shaft 35 is inserted into the upper part of the connecting member 36 and is spline-coupled (engaged) with the connecting member 36. The upper end of the lower drive shaft 38 is inserted into the lower part of the connecting member 36 and is spline-coupled (engaged) with the connecting member 36. The connecting member 36 is rotatably supported by the lower case 11 via a bearing 37.

[0038] (lower drive shaft) 4 is an enlarged view of the lower drive shaft 38 and the lower gear mechanism 45 in FIG. 2. The lower drive shaft 38 extends in the vertical direction and is located below the intermediate drive shaft 35, coaxially arranged with the intermediate drive shaft 35. As shown in FIG. 4, the lower drive shaft 38 is disposed in the drive shaft arranging hole 16 and is rotatably supported in the drive shaft arranging hole 16 via bearings 39 and 40. A spacer 41 for determining the position of the inner rings of the bearings 39 and 40, and a nut 42 for fixing the inner rings of the bearings 39 and 40 to the lower drive shaft 38 are attached to the lower drive shaft 38.

[0039] Furthermore, a main drive gear 46 is integrally formed at the lower end of the lower drive shaft 38. The lower drive shaft 38 and the main drive gear 46 are an integrated, single component, and are formed by, for example, forging and cutting.

[0040] (lower gear mechanism, propeller shaft) The lower gear mechanism 45 is a mechanism that transmits the power of the engine 2, which is transmitted via the upper drive shaft 21, the upper gear mechanism 22, the clutch 27, the intermediate drive shaft 35, the connecting member 36, and the lower drive shaft 38, to the outer propeller shaft 4 and the inner propeller shaft 6. The lower gear mechanism 45 is disposed in the lower gear chamber 15. As shown in FIG. 4 , the lower gear mechanism 45 includes a main drive gear 46, a front driven gear 47, and a rear driven gear 49. Note that although the main drive gear 46 is formed integrally with the lower drive shaft 38, functionally it is one of the components of the lower gear mechanism 45. Furthermore, the main drive gear 46 is a specific example of a "drive gear," and the front driven gear 47 is a specific example of a "driven gear."

[0041] The main drive gear 46 is a bevel gear and is disposed in the upper part of the lower gear chamber 15 with the toothed portion facing downward.

[0042] The front driven gear 47 is a bevel gear and is disposed in the front part of the lower gear chamber 15 so that the toothed portion faces rearward. The front driven gear 47 is rotatably supported by the lower case 11 via a bearing 48. The front driven gear 47 is disposed in front of the main drive gear 46 and is in mesh with the main drive gear 46.

[0043] The rear driven gear 49 is a bevel gear and is disposed in the rear of the lower gear chamber 15 with the toothed portion facing forward. The rear driven gear 49 is rotatably supported by the lower case 11 via a bearing 50. The rear driven gear 49 is disposed behind the main drive gear 46 and is in mesh with the main drive gear 46.

[0044] As shown in Fig. 2, the outer propeller shaft 4 is formed in a cylindrical shape and extends in the front-to-rear direction. The front end portion of the outer propeller shaft 4 is disposed in the propeller shaft disposing hole 17, and is rotatably supported by the lower case 11 via bearings 51 and 52. A rear driven gear 49 is spline-connected (fitted) to the front end portion of the outer propeller shaft 4. This allows the rear driven gear 49 and the outer propeller shaft 4 to rotate integrally. A front propeller 3 is attached to the rear end portion of the outer propeller shaft 4.

[0045] The inner propeller shaft 6 extends in the fore-and-aft direction, and its front portion is disposed within the outer propeller shaft 4. The inner propeller shaft 6 is disposed coaxially with the outer propeller shaft 4. The inner propeller shaft 6 is rotatably supported by the outer propeller shaft 4 and the rear driven gear 49 via bearings 53, 54. The front driven gear 47 is spline-coupled (fitted) to the front end of the inner propeller shaft 6. This allows the front driven gear 47 and the inner propeller shaft 6 to rotate integrally. The rear propeller 5 is attached to the rear end of the inner propeller shaft 6.

[0046] When the main drive gear 46 rotates integrally with the lower drive shaft 38, the rotation is transmitted to the rear driven gear 49 and the front driven gear 47, respectively. As a result, the outer propeller shaft 4 and the inner propeller shaft 6 each rotate. At this time, the outer propeller shaft 4 and the inner propeller shaft 6 rotate in opposite directions. As the outer propeller shaft 4 and the inner propeller shaft 6 rotate, the front propeller 3 and the rear propeller 5 each rotate.

[0047] Furthermore, when the clutch 27 transmits the rotation of the upper drive shaft 21 in the forward direction to the outer propeller shaft 4 and the inner propeller shaft 6 via the intermediate drive shaft 35, the lower drive shaft 38, the lower gear mechanism 45, etc., a thrust force that moves the vessel forward is generated by the front propeller 3 and the rear propeller 5. Furthermore, when the clutch 27 transmits the rotation of the reverse output gear 25 in the reverse direction to the outer propeller shaft 4 and the inner propeller shaft 6 via the intermediate drive shaft 35, the lower drive shaft 38, the lower gear mechanism 45, etc., a thrust force that moves the vessel backward is generated by the front propeller 3 and the rear propeller 5.

[0048] (Setting component placement hole, gear position setting component) FIG. 5 shows the lower gear chamber 15 without the lower gear mechanism 45 and the like. As shown in FIG. 5, a setting member arrangement hole 61 is formed in the front part of the lower gear chamber 15 in the lower case 11. The setting member arrangement hole 61 is a bottomed hole that extends forward from the lower gear chamber 15 and has a circular cross section. The setting member arrangement hole 61 is formed so as to be coaxial with the front driven gear 47 that is arranged in the lower gear chamber 15. A screw 62 having an axis that extends in the front-rear direction is formed on the circumferential surface near the opening at the rear of the setting member arrangement hole 61. The screw 62 is a specific example of a "first screw."

[0049] As shown in FIG. 2 , a vertical hole 63 extending downward from the upper portion of the lower case 11 is formed above the holding member arrangement hole 61 in the lower case 11. As shown in FIG. 5 , an insertion hole 65 is formed in a partition 64 between the vertical hole 63 and the holding member arrangement hole 61. The insertion hole 65 penetrates the partition 64 in the vertical direction, and the lower end of the insertion hole 65 opens at the uppermost portion of the circumferential surface of the holding member arrangement hole 61. The insertion hole 65 is located in the front portion (the back portion) of the holding member arrangement hole 61 and is located in front of the screws 62. A stopper hole 66 is formed in the lowermost portion of the circumferential surface of the holding member arrangement hole 61. The stopper hole 66 is a bottomed hole extending downward from the lowermost portion of the circumferential surface of the holding member arrangement hole 61, is located directly below the insertion hole 65, and is coaxial with the insertion hole 65. In this embodiment, the insertion hole 65 and the stopper hole 66 have the same diameter.

[0050] 4, a gear position setting member 67 is provided in the setting member arrangement hole 61. The gear position setting member 67 is located in front of the front driven gear 47. The gear position setting member 67 has the function of setting the position of the front driven gear 47 in the front-to-rear direction.

[0051] Fig. 6 shows the gear position setting member 67 as seen from the front. Fig. 7(A) shows the gear position setting member 67 as seen from the left. Fig. 7(B) shows a cross section of the gear position setting member 67 taken along line VII-VII in Fig. 6 as seen from the left, and also shows tool 81.

[0052] 6 and 7(A), the gear position setting member 67 is made of, for example, a metal material and is formed into a bottomed cylindrical shape having an axis A extending in the front-rear direction. The outer diameter of the gear position setting member 67 is set to a value slightly smaller than the inner diameter of the setting member arranging hole 61 so that the gear position setting member 67 can rotate coaxially with the setting member arranging hole 61 without shifting position in the up-down or left-right directions within the setting member arranging hole 61. In addition, the gear position setting member 67 is arranged coaxially with the front driven gear 47.

[0053] A screw 68 having an axis extending in the front-rear direction is formed on the outer peripheral surface of the gear position setting member 67. The screw 68 of the gear position setting member 67 is threadedly engaged with the screw 62 of the setting member arrangement hole 61. The screw 68 is a specific example of a "second screw."

[0054] The screw 62 of the setting member arrangement hole 61 and the screw 68 of the gear position setting member 67 constitute a screw mechanism that moves the gear position setting member 67 in the front-to-rear direction within the setting member arrangement hole 61 when the gear position setting member 67 is rotated about its axis A. When the gear position setting member 67 arranged in the setting member arrangement hole 61 is viewed from the rear, when the gear position setting member 67 is rotated clockwise, the screw 68 rotates clockwise relative to the screw 62, causing the gear position setting member 67 to move forward. On the other hand, when the gear position setting member 67 is rotated counterclockwise, the screw 68 rotates counterclockwise relative to the screw 62, causing the gear position setting member 67 to move rearward.

[0055] As shown in FIGS. 6 and 7(B), a tool mounting hole 69 is provided in the center of the gear position setting member 67 for mounting a tool 81 for rotating the gear position setting member 67 about its axis A. The tool mounting hole 69 has a rectangular (e.g., hexagonal) opening. As shown in FIG. 8(C), the tool 81 has a rod-shaped shaft portion 82 that is long enough to reach the tool mounting hole 69 of the gear position setting member 67 disposed in the setting member disposing hole 61, via the propeller shaft disposing hole 17 from the rear of the lower case 11. As shown in FIG. 7(B), a fitting portion 83 having a rectangular (e.g., hexagonal) cross section that can be fitted into the tool mounting hole 69 is provided at the tip of the shaft portion 82. The tool mounting hole 69 is a specific example of a "tool mounting portion."

[0056] 4, a rear end surface 67A of the outer peripheral portion of the gear position setting member 67 contacts the front end surface of the outer ring 48A of the bearing 48 that supports the front driven gear 47 on the lower case 11. By rotating the gear position setting member 67 clockwise using a tool 81, it is possible to move the front driven gear 47 and the bearing 48 forward. By rotating the gear position setting member 67 counterclockwise using the tool 81, it is possible to push the front driven gear 47 and the bearing 48 and move them rearward.

[0057] As shown in FIG. 7A , the gear position setting member 67 has a ring-shaped annular portion 70 that protrudes forward from its outer periphery. A plurality of locking recesses 71 are formed at the front end of the ring-shaped portion 70 at equal intervals around the entire circumference. The number of locking recesses 71 is an even number, e.g., 16. As shown in FIG. 4 , a fixing member 72 that fixes the gear position setting member 67 to prevent rotation is removably provided in the setting member arrangement hole 61 of the lower case 11. The fixing member 72 is a long, tubular member made of, for example, a metal material. The fixing member 72 is inserted into an insertion hole 65 formed in the partition wall 64 and a stopper hole 66 formed around the setting member arrangement hole 61. The diameter of the fixing member 72 is set to be slightly smaller than the diameters of the insertion hole 65 and the stopper hole 66 so that the fixing member 72 can be inserted into and removed from the insertion hole 65 and the stopper hole 66 and fits snugly into them. When the fixing member 72 is inserted into the insertion hole 65 and the stop hole 66, the fixing member 72 engages with, for example, two of the sixteen locking recesses 71 of the gear position setting member 67 that face each other (see FIG. 6). This prevents the gear position setting member 67 from rotating within the setting member arrangement hole 61. By fixing the gear position setting member 67 to be non-rotatable with the fixing member 72, the positions of the front driven gear 47 and the bearing 48 in the front-to-rear direction can be determined.

[0058] Furthermore, the fixing member 72 can be pulled out from the insertion hole 65 and the stop hole 66 by inserting a hand or a tool through the vertical hole 63, for example. With the fixing member 72 pulled out, it becomes possible to rotate the gear position setting member 67 using a tool 81, and by rotating the gear position setting member 67, it becomes possible to change the positions of the front driven gear 47 and the bearing 48 in the front-to-rear direction.

[0059] In this embodiment, the fixed member 72 also functions as an oil supply pipe that supplies lubricating oil into the lower gear chamber 15. As shown in the lower left of Fig. 4, the interior of the fixed member 72 forms an oil distribution portion 73 that distributes lubricating oil, and the lower end of the fixed member 72 is formed with an oil outflow hole 74 that allows the lubricating oil to flow into the lower gear chamber 15. In addition, an oil introduction pipe 75 that allows lubricating oil to flow into the fixed member 72 from the outside of the lower case 11 can be connected to the upper end of the fixed member 72.

[0060] (Assembly of the lower drive shaft) 8(A) to 8(D) show the process of assembling the lower drive shaft 38, which is integrally formed with the main drive gear 46, into the lower case 11. In FIGS. 8 and 4, P indicates the position where the front driven gear 47 is meshed with the main drive gear 46 (more specifically, the position in the front-to-rear direction of the rear end (tip) of the front driven gear 47 when the front driven gear 47 is meshed with the main drive gear 46). Hereinafter, this position will be referred to as the "set position P."

[0061] In the outboard motor 1 of this embodiment, the lower drive shaft 38 is assembled into the lower case 11 as follows.

[0062] First step: The worker first uses the tool 81 to rotate the gear position setting member 67 provided in the setting member arrangement hole 61, and moves the gear position setting member 67, for example, to near the front-most position within the setting member arrangement hole 61. In this state, the worker inserts the bearing 48 and the front driven gear 47 from the rear of the lower case 11 into the lower gear chamber 15 through the propeller shaft arrangement hole 17, and attaches the bearing 48 and the front driven gear 47 to the front portion of the lower gear chamber 15. The worker then pushes the bearing 48 and the front driven gear 47 forward so that the front end surface of the outer ring 48A of the bearing 48 contacts the rear end surface 67A of the gear position setting member 67. As a result, the front driven gear 47 is positioned forward of the setting position P. In this way, by moving the gear position setting member 67 to, for example, near the foremost position within the setting member arrangement hole 61, the front driven gear 47 can be arranged further forward than the set position P.

[0063] Second step: As shown in FIG. 8(A), with the front driven gear 47 positioned forward of the set position P, the worker then inserts the lower drive shaft 38 from the rear of the lower case 11 to the propeller shaft. arrangement hole 17 The lower drive shaft 38 is inserted into the lower gear chamber 15 via the propeller shaft mounting hole 17. At this time, the worker inserts the lower drive shaft 38 into the propeller shaft mounting hole 17 from the end (upper end) on the side where the main drive gear 46 is not integrally formed, and carries it into the lower gear chamber 15.

[0064] Third step: Next, the worker rotates the lower drive shaft 38 placed in the lower gear chamber 15 so that the end on the side where the main drive gear 46 is not integrally formed faces upward, and inserts the lower drive shaft 38 from below into the drive shaft mounting hole 16 as shown in Figure 8(B).Then, the lower drive shaft 38 is attached to the drive shaft mounting hole 16.

[0065] Fourth step: Next, as shown in Figure 8 (C), the worker inserts a tool 81 into the propeller shaft arrangement hole 17 from the rear of the lower case 11, and then passes the tool 81 through the shaft hole 47A of the front driven gear 47, and fits the fitting portion 83 provided at the tip of the tool 81 into the tool mounting hole 69 of the gear position setting member 67.

[0066] Fifth step: Next, the worker rotates the tool 81 in the direction of the arrow in Figure 8(C), thereby rotating the gear position setting member 67 and moving the gear position setting member 67 rearward. As a result, the bearing 48 and the front driven gear 47 are pushed by the gear position setting member 67 and move rearward. The worker rotates the tool 81 to move the front driven gear 47 to the set position P, and meshes the front driven gear 47 with the main drive gear 46.

[0067] 8(D), the worker then inserts the fixing member 72 into the vertical hole 63 from above the lower case 11, and sequentially inserts the fixing member 72 into the insertion hole 65, the locking recesses 71 of the gear position setting member 67, and the retaining hole 66. As a result, the gear position setting member 67 is fixed unrotatably within the setting member disposing hole 61, the position of the gear position setting member 67 in the front-to-rear direction is fixed, and the position of the front driven gear 47 in the front-to-rear direction is determined to be the setting position P.

[0068] For example, during the manufacture of the outboard motor 1, after assembling the lower drive shaft 38, which is integrally formed with the main drive gear 46, and the front driven gear 47 into the lower case 11 in this manner, a worker will then perform tasks such as assembling the rear driven gear 49, the inner propeller shaft 6, and the outer propeller shaft 4 into the lower gear chamber 15 and the propeller shaft arrangement hole 17, connecting the intermediate drive shaft 35 to the lower drive shaft 38 via the connecting member 36, and assembling the upper gear mechanism 22 and clutch 27 into the upper gear chamber 14.

[0069] The second and third steps are specific examples of a "drive shaft insertion step." The fourth step is a specific example of a "tool attachment step." The fifth step is a specific example of a "driven gear movement step."

[0070] (Adjusting the meshing between the main drive gear and the front driven gear) In the outboard motor 1 of this embodiment, an operator can adjust the meshing (tooth contact, backlash, etc.) between the main drive gear 46 and the front driven gear 47 as follows. The operator first removes the rear driven gear 49, the inner propeller shaft 6, and the outer propeller shaft 4 from the lower case 11. Next, the operator uses the tool 81 to rotate the gear position setting member 67, change the position of the front driven gear 47 in the fore-and-aft direction, and adjust the meshing between the main drive gear 46 and the front driven gear 47. Next, the operator assembles the rear driven gear 49, the inner propeller shaft 6, and the outer propeller shaft 4 into the lower case 11.

[0071] As described above, the outboard motor 1 of this embodiment is equipped with the gear position setting member 67, which sets the longitudinal position of the front driven gear 47, and the screw mechanism (screws 62 and 68), which moves the gear position setting member 67 in the longitudinal direction when the gear position setting member 67 is rotated about its axis A. This allows the lower drive shaft 38, which is integrally formed with the main drive gear 46, to be assembled into the lower case 11 by changing the longitudinal position of the front driven gear 47. That is, with the outboard motor 1 of this embodiment, the front driven gear 47 mounted in the lower gear chamber 15 can be moved forward from the set position P by moving the gear position setting member 67 forward. This allows the front driven gear 47 to be moved away from the opening of the drive shaft mounting hole 16 into the lower gear chamber 15. As a result, the free space below the drive shaft mounting hole 16 in the lower gear chamber 15 can be expanded. Therefore, when the lower drive shaft 38, which is integrally formed with the main drive gear 46, is passed through the propeller shaft arrangement hole 17 and the lower gear chamber 15 from the rear of the lower case 11 and inserted into the drive shaft arrangement hole 16 from below, it is possible to prevent the front driven gear 47 from contacting the lower drive shaft 38 or the main drive gear 46 and interfering with the insertion of the lower drive shaft 38 into the drive shaft arrangement hole 16. Therefore, the lower drive shaft 38, which is integrally formed with the main drive gear 46, can be assembled into the lower case 11 by passing the lower drive shaft 38, which is integrally formed with the main drive gear 46, through the propeller shaft arrangement hole 17 and the lower gear chamber 15 from the rear of the lower case 11, and inserting it into the drive shaft arrangement hole 16 from below to attach it to the drive shaft arrangement hole 16.

[0072] Furthermore, with the outboard motor 1 of this embodiment, the lower drive shaft 38, onto which the main drive gear 46 is integrally formed, can be attached from below into the drive shaft mounting hole 16 through the propeller shaft mounting hole 17 and the lower gear chamber 15 of the lower case 11, so that the lower drive shaft 38, onto which the main drive gear 46 is integrally formed, can be assembled into the lower case 11 without adding a large-diameter hole to the lower case 11 for passing the main drive gear 46, which is integrally formed with the lower drive shaft 38. Therefore, it is possible to prevent the width of the lower case 11 from increasing due to the addition of a large-diameter hole to the lower case 11, and to prevent an increase in water resistance during sailing.

[0073] Furthermore, the outboard motor 1 of this embodiment is provided with the gear position setting member 67 and the screw mechanism (screws 62, 68), which allows for easy and quick meshing adjustment between the main drive gear 46 and the front driven gear 47 by changing the longitudinal position of the front driven gear 47. In other words, in conventional outboard motors, meshing adjustment between the drive gear and the front driven gear is performed by replacing a shim attached to the boss of the front driven gear with a different shim of a different thickness. Therefore, to adjust meshing between the drive gear and the front driven gear, it is necessary to remove the drive gear and the front driven gear from the lower case. In contrast, the outboard motor 1 of this embodiment allows meshing adjustment between the main drive gear 46 and the front driven gear 47 by changing the longitudinal position of the front driven gear 47 while the main drive gear 46 and the front driven gear 47 are attached to the lower case 11. Therefore, when adjusting the meshing between the main drive gear 46 and the front driven gear 47, it is possible to omit the process of attaching and detaching the main drive gear 46 and the front driven gear 47 to and from the lower case 11. This reduces the number of steps required to adjust the meshing between the main drive gear 46 and the front driven gear 47, making the meshing adjustment easier and faster. Furthermore, according to this embodiment, such an effect can be obtained with a simple structure in which the gear position setting member 67 is moved by a screw mechanism.

[0074] In the outboard motor 1 of this embodiment, the gear position setting member 67 is provided at its center with a tool attachment hole 69 for attaching a tool 81 for rotating the gear position setting member 67. With this configuration, the tool 81 can be attached to the gear position setting member 67 from the rear of the lower case 11 through the propeller shaft arrangement hole 17 and the shaft hole 47A of the front driven gear 47, and the gear position setting member 67 can be rotated using the tool 81 to easily change the fore-and-aft position of the front driven gear 47. This makes it easy to install the lower drive shaft 38, with which the main drive gear 46 is integrally formed, into the lower case 11 and to adjust the meshing between the main drive gear 46 and the front driven gear 47.

[0075] The outboard motor 1 of this embodiment also includes a fixing member 72 that is detachably mounted in a setting member mounting hole 61 formed in the lower gear chamber 15 and that non-rotatably fixes the gear position setting member 67. With this configuration, an operator can switch between a state in which the gear position setting member 67 is movable in the fore-and-aft direction and a state in which the gear position setting member 67 is immovable in the fore-and-aft direction simply by attaching or detaching the fixing member 72 to or from the setting member mounting hole 61. This makes it even easier to install the lower drive shaft 38, with which the main drive gear 46 is integrally formed, into the lower case 11 and to adjust the meshing between the main drive gear 46 and the front driven gear 47. In particular, according to this embodiment, simply by inserting and removing the fixing member 72 into the insertion hole 65, the stop hole 66, and the locking recess 71 of the gear position setting member 67, it is possible to switch between a state in which the gear position setting member 67 is movable in the front-rear direction and a state in which the gear position setting member 67 is unable to move in the front-rear direction, thereby making it even easier to assemble the lower drive shaft 38 and adjust the meshing.

[0076] In the outboard motor 1 of this embodiment, the intermediate drive shaft 35 and the lower drive shaft 38 are connected by the connecting member 36. This configuration makes it possible to shorten the length of the lower drive shaft 38, which is integrally formed with the main drive gear 46. Therefore, the lower drive shaft 38, which is integrally formed with the main drive gear 46, can be passed through the propeller shaft mounting hole 17 and the lower gear chamber 15 from the rear of the lower case 11, and then smoothly inserted into the drive shaft mounting hole 16 from below.

[0077] In this embodiment, the fixing member 72 not only functions to fix the gear position setting member 67, but also functions as an oil supply pipe that supplies lubricating oil to the lower gear chamber 15. This allows the number of oil supply pipes to be reduced, and the number of parts in the outboard motor 1 to be reduced.

[0078] In addition, in this embodiment, the main drive gear 46 is formed integrally with the lower drive shaft 38, which increases the strength of the connection between the lower drive shaft 38 and the main drive gear 46. This increases the stability of power transmission from the lower drive shaft 38 to each of the propeller shafts 4, 6.

[0079] The screw mechanism that moves the gear position setting member in the forward / backward direction when the gear position setting member is rotated is not limited to the screws 62 and 68 of the above-described embodiment. The tool attachment portion of the gear position setting member is not limited to the tool attachment hole 69 of the above-described embodiment. The configuration of the locking portion that engages with the fixing member to disable rotation of the gear position setting member is not limited to the locking recess 71 of the above-described embodiment. As shown in FIG. 9 , the screw mechanism may be configured such that a protrusion 92 that protrudes rearward from the center of the front (bottom) of a setting member arrangement hole 91 is provided, and a thread 93 is formed on the outer circumferential surface of the protrusion 92. Meanwhile, a threaded hole 95 with a thread 96 formed on the inner circumferential surface is formed in the center of the front (bottom) of a gear position setting member 94 that is cylindrical and has a bottom, and the protrusion 92 is inserted into the threaded hole 95, and the screw 96 and the screw 93 are threadedly engaged with each other. The tool mounting portion may be configured to have a tool mounting protrusion 97 that protrudes rearward from the center and has a rectangular (e.g., hexagonal) cross section at the front (bottom) of the gear position setting member 94. The locking portion may be configured to have a locking hole 98 that is long in the front-to-rear direction at the peripheral wall of the gear position setting member 94.

[0080] Furthermore, in the above embodiment, the tubular fixed member 72 that functions as an oil supply pipe is given as an example, but the fixed member may be a simple pin- or rod-shaped member that does not function as an oil supply pipe.

[0081] Furthermore, the present invention is not limited to contra-rotating propeller outboard motors, but can also be applied to outboard motors with a single propeller shaft, as long as the outboard motor has a drive gear connected to the lower end of a drive shaft and a driven gear that meshes with the drive gear from the front.

[0082] Furthermore, the present invention may be modified as appropriate within the scope of the claims and the spirit or concept of the invention as can be read from the entire specification, and outboard motors and drive shaft assembly methods involving such modifications are also included within the technical concept of the present invention. [Explanation of symbols]

[0083] 1 outboard motor 4 Outer propeller shaft (propeller shaft) 6 Inner propeller shaft (propeller shaft) 11 Lower case (case) 15 Lower gear chamber (gear chamber) 16 Drive shaft placement hole 17 Propeller shaft arrangement hole 38 Lower drive shaft (drive shaft) 46 Main drive gear (drive gear) 47 Front driven gear (driven gear) 61, 91 Setting component placement holes 62, 93 Screws (first screws) 67 Gear position setting member 68, 96 screws (second screws) 69 Tool mounting hole (tool mounting part) 72 Fixing member 81 Tools 97 Tool mounting protrusion (tool mounting part)

Claims

1. a case having a gear chamber, a drive shaft arrangement hole communicating with the gear chamber from above the gear chamber, and a propeller shaft arrangement hole communicating with the gear chamber from behind the gear chamber; a drive shaft extending in the vertical direction and disposed in the drive shaft disposing hole; a propeller shaft extending in the front-rear direction and disposed in the propeller shaft disposing hole; a drive gear that is a bevel gear and is coupled to a lower end side of the drive shaft and is disposed within the gear chamber; a driven gear, the driven gear being a bevel gear coupled to a front end side of the propeller shaft, disposed in front of the drive gear in the gear chamber, and meshed with the drive gear; a gear position setting member provided in front of the driven gear in the case and configured to set a position of the driven gear in the front-rear direction; a screw mechanism that moves the gear position setting member in the front-rear direction when the gear position setting member is rotated about an axis of the gear position setting member that extends in the front-rear direction, The screw mechanism includes: a first screw provided in the case and having an axis extending in the front-rear direction; a second screw provided on the gear position setting member, having an axis extending in the front-rear direction, and threadedly engaging with the first screw; the gear position setting member expands the free space within the gear chamber so that the drive shaft, to which the drive gear is connected, can be inserted into the drive shaft arrangement hole through the propeller shaft arrangement hole and the gear chamber by moving the driven gear forward from a set position at which the driven gear meshes with the drive gear, while moving the driven gear to the set position to cause the driven gear to mesh with the drive gear.

2. The gear position setting member is formed in a columnar or bottomed cylindrical shape having an axis extending in the front-rear direction, 2. The outboard motor according to claim 1, wherein a tool attachment portion for attaching a tool for rotating the gear position setting member is provided at a center portion of the gear position setting member.

3. 3. An outboard motor according to claim 1, further comprising a fixing member detachably mounted on the case for non-rotatably fixing the gear position setting member to the case.

4. An oil supply pipe detachably provided on the case for supplying lubricating oil into the gear chamber, 3. An outboard motor according to claim 1, wherein the gear position setting member is non-rotatably fixed to the case by being engaged with the oil supply pipe.

5. 5. An outboard motor according to claim 1, wherein the drive gear is integrally formed with the drive shaft.

6. a case having a gear chamber, a drive shaft arrangement hole communicating with the gear chamber from above the gear chamber, and a propeller shaft arrangement hole communicating with the gear chamber from behind the gear chamber; a drive shaft extending in the vertical direction and disposed in the drive shaft disposing hole; a propeller shaft extending in the front-rear direction and disposed in the propeller shaft disposing hole; a drive gear which is a bevel gear and is integrally formed with the drive shaft at a lower end side of the drive shaft and is disposed within the gear chamber; a driven gear, the driven gear being a bevel gear coupled to a front end side of the propeller shaft, disposed in front of the drive gear in the gear chamber, and meshed with the drive gear; a gear position setting member provided in front of the driven gear in the case and configured to set a position of the driven gear in the front-rear direction; a screw mechanism that moves the gear position setting member in a fore-and-aft direction when the gear position setting member is rotated about an axis of the gear position setting member that extends in the fore-and-aft direction, the screw mechanism comprising: a drive shaft inserting step of inserting the drive shaft from the propeller shaft arrangement hole into the gear chamber in a state in which the driven gear is arranged forward of a set position at which the driven gear is meshed with the drive gear, and subsequently inserting the drive shaft from the gear chamber into the drive shaft arrangement hole; a tool attachment step of inserting a tool for rotating the gear position setting member into the gear chamber through the propeller shaft arrangement hole and attaching the tool to the gear position setting member; a driven gear moving step of rotating the gear position setting member with the tool to move the driven gear to the set position and mesh with the drive gear.

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