Outboard motor

Abstract

This invention provides a single-unit, dual-shaft outboard motor that balances the steering force when turning the steering wheel left and right, while also improving the straight-line stability of the hull. [Solution] The outboard motor 1 has a power transmission system comprising a drive shaft 6 that rotates coaxially with the power source 5, a first bevel angular 19 that rotates coaxially with the drive shaft 6, a port side driven shaft 7 that rotates coaxially with a second bevel angular 20 that is inclined to connect with the first bevel angular 19, a starboard side driven shaft 8 that rotates coaxially with a third bevel angular 21 that is inclined to connect with the first bevel angular 19, a left propeller shaft 10 that extends aft and intersects with the port side driven shaft 7 to transmit rotation to the left propeller 30, and a right propeller shaft 11 that extends aft and intersects with the starboard side driven shaft 8 to transmit rotation to the right propeller 31.

Description

[Technical Field]

[0001] The present invention relates to an outboard motor that provides propulsion to a hull. [Background Art]

[0002] As an advantage, the outboard motor is structured to be mainly attached to the transom board (stern plate) of a hull. Therefore, compared with other propulsion machines such as inboard-outboard motors and inboard motors, it can be attached and detached very easily and is easy to handle. Especially for small outboard motors, the outboard motor body is equipped with a fuel tank, a forward / reverse switching lever, a throttle grip, a steering bar and the like, and ship maneuvering can be performed by operating these components. In addition, particularly small outboard motors are easy to transport, and can be easily removed from the hull for loading onto a vehicle or storage in a warehouse.

[0003] However, in the conventional single-unit single-shaft type outboard motor, a force in a direction that hinders the straight-line stability of the hull acts on the hull due to the action of the lateral pressure (counter torque) of the propeller (or screw; hereinafter referred to as propeller). As a result, there has been a problem that imbalance occurs between the left and right steering forces.

[0004] Therefore, in order to eliminate the imbalance between the left and right steering forces, measures are taken as follows: a plurality of outboard motors are installed on the port side and the starboard side of the transom board of the hull respectively to cancel out the lateral pressure (counter torque); or the propeller of the outboard motor is of a contra-rotating type, and the propeller mounted on the outer shaft and the propeller mounted on the inner shaft which share the same center line are rotated in opposite directions to counteract the counter torque. Furthermore, a power steering device for mounting on an outboard motor disclosed in Patent Document 1 has been put into practical use. [Prior Art Literature] [Patent Literature]

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 01-314695 [Brief Summary of the Invention] [Problem to be Solved by the Invention]

[0006] However, in the case of a contra-rotating propeller, the cylindrical outer shaft and the inner shaft that rotates inside the cylindrical outer shaft rotate in opposite directions around the same rotational centerline, resulting in a high relative speed. Therefore, a high degree of machining precision is required for the bearings and other parts, and the complex mechanism leads to frequent maintenance and increased costs. Similarly, in the case of power steering systems, there is a tendency for costs to increase and the number of parts requiring maintenance to increase.

[0007] Therefore, the present invention has been made to solve the above problems, and aims to provide a single-unit, dual-shaft outboard motor that can be manufactured using conventional outboard motor manufacturing technology without requiring advanced mechanisms or processing precision, and that enhances straight-line stability and docking / undocking capabilities, while also being able to handle high power output. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a power source 5, a drive shaft 6 that rotates and is driven coaxially by the power source 5 and extends downward, a first bevel angular 19 that rotates coaxially with the drive shaft 6 and has its smaller diameter side facing upward, a second bevel angular 20 that is always connected to the first bevel angular 19 in an inclined manner with its smaller diameter side facing upward, a port side driven shaft 7 that rotates coaxially with the second bevel angular 20 and extends in an oblique downward direction on the port side, a third bevel angular 21 that is always connected to the first bevel angular 19 in an inclined manner and rotates in the same direction as the second bevel angular 20, and coaxially with the third bevel angular 21 This outboard motor has a power transmission system comprising a power two-way transmission mechanism 9 which consists of a starboard driven shaft 8 that rotates and extends diagonally downward on the starboard side, a port propeller shaft 10 connected to the port driven shaft 7 and extending in a direction intersecting the axis of the port driven shaft 7, a port propeller 30 that rotates on the port propeller shaft 10, a starboard propeller shaft 11 connected to the starboard driven shaft 8 and extending in a direction intersecting the axis of the starboard driven shaft 8, a starboard propeller 31 that rotates on the starboard propeller shaft 11, the first bevel angular 19, the second bevel angular 20, and the third bevel angular 21, thereby providing a straight thrust to the hull 200. Preferably, the third bevel angular 21 is located on the opposite side of the second bevel angular 20, with the first bevel angular 19 in between.

[0009] Furthermore, the present invention also includes a power source 5, drive shafts 92 and 100 that rotate and are driven coaxially by the power source 5 and extend downward, a fourth bevel angular 95 that rotates coaxially with respect to the drive shafts 92 and 100 and has its smaller diameter side facing upward, a fifth bevel angular 96 that is constantly meshed with the fourth bevel angular 95 in an inclined manner and has its smaller diameter side facing upward, driven shafts 93 and 101 that rotate coaxially with respect to the fifth bevel angular 96 and extend downward, and a propeller shaft 10 that is connected to the drive shafts 92 and 100 and extends in a direction intersecting the axes of the drive shafts 92 and 100, and the This outboard motor has a power transmission system comprising a port-side propeller 30 rotated by a propeller shaft 10, a propeller shaft 11 connected to the driven shafts 93 and 101 and extending in a direction intersecting the axes of the driven shafts 93 and 101, a starboard-side propeller 31 rotated by the propeller shaft 11, a power branching transmission mechanism 94 consisting of the fourth bevel angular 95 and the fifth bevel angular 96, and a power transmission system that provides straight thrust to the hull 200. [Effects of the Invention]

[0010] The single-unit, dual-shaft outboard motor of the present invention has one power source and two shafts, a port-side propeller shaft and a starboard-side propeller shaft, to secure a large propeller area and enable high output from the outboard motor. Furthermore, because it is a single-unit, dual-shaft outboard motor, for example, by generating thrust for forward (or reverse) movement on the port-side propeller and thrust for reverse (or forward) movement on the starboard propeller, the bow of the hull can be turned to the right (or left) within a narrow range. This allows a single outboard motor to change the direction of the hull's bow within a narrow range, similar to a dual outboard motor, and provides benefits such as improved stability during steering, including easier docking and undocking. [Brief explanation of the drawing]

[0011] [Figure 1] This is a rear view showing mainly the power transmission system of an outboard motor according to the first embodiment of the present invention. [Figure 2]This is a side view from the port side of the port side gear mechanism located inside the port side gear case of an outboard motor according to the first embodiment of the present invention. [Figure 3] This is a side view, seen from the port side, of the starboard gear mechanism located inside the starboard gear case of an outboard motor according to the first embodiment of the present invention. [Figure 4] This is a schematic diagram showing the positional relationship of the gear shift handles for port and starboard sides, the lever shift rods for port and starboard sides, the flexible outer cases for port and starboard sides, the push-pull flexible inner cables for port and starboard sides, and the shift cams for port and starboard sides, which constitute the shift mechanism of an outboard motor according to the first embodiment of the present invention. [Figure 5] This is a schematic diagram showing the relative positions of the intake, water pump, port side cooling water channel, starboard side cooling water channel, and upper cooling water channel that constitute the cooling water channel of an outboard motor according to the first embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating the rotation stop mechanism of an outboard motor according to the first embodiment of the present invention. [Figure 7] This is a schematic plan view of the anti-cavitation plate of an outboard motor according to the first embodiment of the present invention. [Figure 8] This is a rear view of the anti-cavitation plate of an outboard motor according to the first embodiment of the present invention. [Figure 9] This is a schematic rear view showing the power transmission system in another outboard motor in which a constant velocity joint is interposed at an appropriate point along the main drive shaft of the outboard motor according to the first embodiment of the present invention. [Figure 10] This is a schematic side view of a lower case rotation adjustment mechanism of another outboard motor, in which a constant velocity joint is interposed at an appropriate point along the main drive shaft of an outboard motor according to the first embodiment of the present invention. [Figure 11] This is a schematic rear view showing a lower case rotation adjustment mechanism for another outboard motor, in which a constant velocity joint is interposed at an appropriate point along the main drive shaft of an outboard motor according to the first embodiment of the present invention. [Figure 12]It is a schematic perspective view showing the port-side and starboard-side attachment portions for attaching the port-direction and starboard-direction damper mounts of another outboard motor, in which a constant velocity joint is interposed at an appropriate position in the middle of the main drive shaft of the outboard motor according to the first embodiment of the present invention, to the upper carrier body side. [Figure 13] It is a rear view showing a power transmission system of the outboard motor according to the first embodiment of the present invention and still another outboard motor. [Figure 14] It is a rear view showing a power transmission system of the outboard motor according to the first embodiment of the present invention and still another outboard motor. [Mode for Carrying Out the Invention]

[0012] Embodiments of the present invention will be described with reference to the drawings. The same reference numerals are used for the same elements, and overlapping descriptions are omitted.

[0013] (First Embodiment) The first embodiment of the present invention will be described. Figure 1 is a rear view showing a power transmission system in a one-unit two-shaft type outboard motor 1 (hereinafter referred to as outboard motor 1) according to the first embodiment of the present invention. The outboard motor 1, which provides thrust to the hull, is attached to a transom board (stern plate) of the hull in a state that it can rotate vertically and horizontally via a steering mechanism (not shown) consisting of a swivel bracket and a clamp bracket.

[0014] The outboard motor 1 will be described in detail. In the outboard motor 1, an upper power unit 15 is arranged at a head portion, the upper power unit 15 having a cowl 2 for protecting an engine 5, which is a power source, fitted over an engine holder 16 with the engine 5 arranged and fixed on an upper portion of the engine holder 16. Alternatively, the power source may include an electric motor. In a middle part below the upper power unit 15, there is arranged a carrier body 3 constituting a lower unit 4, in which an oil case (not shown) storing oil for lubricating and cooling the engine, and a muffler (not shown) connected to an end portion of an exhaust pipe (not shown) that passes through a hollow portion vertically penetrating the oil case, etc. are disposed inside. Further, in a lower part below the carrier body 3, there is arranged an integrally configured gear case 34 that constitutes the lower unit 4, wherein the gear case 34 is provided by extending a port-side gear case 34a obliquely downward toward the port side and a starboard-side gear case 34b obliquely downward toward the starboard side respectively.

[0015] The upper power unit 15, the carrier body 3 constituting the lower unit 4, and the gear case 34 are integrally connected and combined to form the outboard motor 1. The outboard motor 1 provides thrust to a hull 200.

[0016] The engine 5 serving as the power source includes a crankshaft 17. The crankshaft 17 extends in a substantially vertical direction relative to a water surface. A drive shaft 6 is coaxially coupled and connected to a lower portion of the crankshaft 17 by, for example, spline fitting, and extends downward in the carrier body 3. Note that the drive shaft 6 may be arranged coaxially, parallel, or perpendicular to the crankshaft 17.

[0017] The drive shaft 6 has a first bevel gear 19 fixed therein, the first bevel gear 19 being arranged with its small-diameter side facing upward relative to the water surface inside an upper gear box 35, the upper gear box 35 storing lubricating oil in an internal space provided at an appropriate position midway between the connection position of the crankshaft 17 and the drive shaft 6 and the mounting position of a water pump 18 (inside the carrier body 3 constituting the lower unit 4 or inside the gear case 34). Further, the first bevel gear 19 rotates coaxially with the drive shaft 6.

[0018] The drive shaft 6 has its lower end protruding downwards from the upper gearbox 35, and the lower end of the protruding drive shaft 6 coaxially rotates the impeller (not shown) that constitutes the water pump 18, which is fixedly positioned below the upper gearbox 35. Furthermore, regarding the positioning of the water pump 18, positioning it close to the stern bottom surface of the hull makes it easier to pump water from the navigation area. The same applies to the outboard motor described below.

[0019] The first bevel angular bearing 19 is constantly meshed with and connected to a second bevel angular bearing 20, which is located inside the upper gearbox 35 with its smaller diameter side facing upward relative to the water surface. The second bevel angular bearing 20 is fixed to the upper end of the port side driven shaft 7, and the port side driven shaft 7, which rotates coaxially with the second bevel angular bearing 20, extends into the port side gearbox 36, which is formed inside the lower part of the port side lower case 34a shown in Figure 2 and stores lubricating oil in its internal space.

[0020] Furthermore, the first bevel angular bearing 19 is constantly meshed with and connected to the third bevel angular bearing 21, which is located inside the upper gearbox 35 with its smaller diameter side facing upward relative to the water surface. The third bevel angular bearing 21 is fixed to the upper end of the starboard driven shaft 8, and the starboard driven shaft 8, which rotates coaxially with the third bevel angular bearing 21, extends into the starboard gearbox 37, which is formed inside the lower part of the starboard lower case 34b shown in Figure 3 and stores lubricating oil in its internal space. Thus, the port driven shaft 7 and the starboard driven shaft 8 form an inverted V shape extending downward from the upper gearbox 35 side.

[0021] The power transmission mechanism 9 is composed of the first bevel angular contactor 19, the second bevel angular contactor 20 positioned on the port side of the first bevel angular contactor 19 and constantly meshing with it, rotating in the opposite direction to the first bevel angular contactor 19, and the third bevel angular contactor 21 positioned on the starboard side of the first bevel angular contactor 19 and constantly meshing with it, rotating in the opposite direction to the first bevel angular contactor 19 and in the same direction as the second bevel angular contactor 20.

[0022] Furthermore, the rotational centerlines of the second bevel angular 20, which is always meshed and connected to the first bevel angular 19, and the rotational centerlines of the third bevel angular 21, which is always meshed and connected to the first bevel angular 19, are located symmetrically on a plane that includes the rotational center axis of the first bevel angular 19 and is perpendicular to the longitudinal centerline of the outboard motor 1. However, this is not limited to the aforementioned plane; therefore, outside of this plane, the connection between the port side driven shaft 7 and the port side propeller shaft 10, and between the starboard side driven shaft 8 and the starboard side propeller shaft 11, will be oblique connections rather than cross connections.

[0023] Alternatively, the power transmission mechanism 9 may reduce the rotational speed of the drive shaft 6 and transmit it to the port side driven shaft 7 and the starboard side driven shaft 8. By reducing the rotational speed of the engine and transmitting the engine's driving force to the port side gear mechanism 12 and the starboard side gear mechanism 13, the port side gear mechanism 12 and the starboard side gear mechanism 13 do not reduce the rotational speed, and the port side pinion gear 22 and the forward gear, which constitute the port side gear mechanism 12, are transmitted to each other. The outer diameters of gear 24, the reverse gear 25 described later, and the starboard pinion gear 23, reverse gear 28, and forward gear 27 described later, which constitute the starboard gear mechanism 13, can be reduced. This also reduces the outer diameters of the port gearbox 36, which houses the port gear mechanism 12, and the starboard gearbox 37, which houses the starboard gear mechanism 13. As a result, underwater resistance during navigation can be reduced. In the case of an electric motor, it is also possible to increase the speed in order to exert high torque at low rotational speeds.

[0024] As shown in Figure 2, the port side driven shaft 7 is housed in the port side gearbox 36 and constitutes the port side gear mechanism 12, with a port side pinion gear 22 that rotates coaxially with the port side driven shaft 7 fixed to the lower end of the port side driven shaft 7. Similarly, as shown in Figure 3, the starboard side driven shaft 8 is housed in the starboard side gearbox 37 and constitutes the starboard side gear mechanism 13, with a starboard side pinion gear 23 that rotates coaxially with the starboard side driven shaft 8 fixed to the lower end of the starboard side driven shaft 8.

[0025] As shown in Figure 2, the port side pinion gear 22 is constantly meshed and connected to the forward gear 24 and the reverse gear 25 located in front of the port side pinion gear 22, which are rotatably mounted on the port side propeller shaft 10. Furthermore, the forward gear 24 and the reverse gear 25 are selectively meshed with each other in response to a shift operation, thereby connecting the port side propeller shaft 1 A port-side dog clutch 26, which switches the connection between the forward gear 24 and the reverse gear 25 relative to 0, rotates coaxially with the port-side propeller shaft 10 and is assembled in a manner that allows it to slide in the axial direction of the port-side propeller shaft 10. The port-side gear mechanism 12 is composed of the port-side pinion gear 22, the forward gear 24, the reverse gear 25, and the port-side dog clutch 26.

[0026] Furthermore, as shown in Figure 3, the starboard pinion gear 23 is constantly meshed and connected to the reverse gear 28 in front of the starboard pinion gear 23 and the forward gear 27 behind it, which are rotatably mounted on the starboard propeller shaft 11. In addition, the reverse gear 28 and the forward gear 27 are selectively meshed with each other in response to the shift operation, thereby connecting the starboard propeller shaft 11 The starboard dog clutch 29, which switches the connection between the reverse gear 28 and the forward gear 27, rotates coaxially with the starboard propeller shaft 11 and is assembled in a manner that allows it to slide in the axial direction of the starboard propeller shaft 11. The starboard pinion gear 23, the reverse gear 28, the forward gear 27, and the starboard dog clutch 29 constitute the starboard gear mechanism 13.

[0027] A port propeller 30, which generates thrust by rotating to the left, is attached and fixed to the rear end of the port propeller shaft 10, and a starboard propeller 31, which generates thrust by rotating to the right, is attached and fixed to the rear end of the starboard propeller shaft 11. The distance between the port propeller 30 and the starboard propeller 31 may be set narrower than the distance shown in Figure 1 in order to increase the water pressure and thus increase thrust by merging the water flows generated by the inward-rotating sides of each propeller.

[0028] Ultimately, when the outboard motor 1 is viewed from above, for example, when the engine 5 is rotating clockwise, the port side dog clutch 26 engages with the forward gear 24, generating thrust that causes the port side propeller 30 to rotate counterclockwise, propelling the hull 200 forward. Also, when the starboard side dog clutch 29 engages with the forward gear 27, the starboard side propeller 31 rotates clockwise, generating thrust that propells the hull 200 forward.

[0029] Furthermore, when the port side dog clutch 26 engages with the reverse gear 25, thrust is generated to rotate the port side propeller 30 clockwise, in the same direction as the port side propeller 30, thereby moving the hull 200 in reverse. Also, when the starboard side dog clutch 29 engages with the reverse gear 28, thrust is generated to rotate the starboard side propeller 31 counterclockwise, thereby moving the hull 200 in reverse.

[0030] The first bevel angular bearing 19, which rotates coaxially with the drive shaft 6 and constitutes the power bipartite transmission mechanism 9, the second bevel angular bearing 20, which rotates coaxially with the port side driven shaft 7 and constitutes the power bipartite transmission mechanism 9, and the third bevel angular bearing 21, which rotates coaxially with the starboard side driven shaft 8 and constitutes the power bipartite transmission mechanism 9, are housed in the upper gearbox 35 and are lubricated by the lubricating oil in the upper gearbox 35. In addition, an oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil in the upper gearbox 35 are provided at desired positions in the upper gearbox 35.

[0031] Furthermore, the outboard motor 1 comprises a port side pinion gear 22 arranged in a port side gearbox 36 formed inside the lower part of the port side gear case 34a which extends diagonally downward on the port side of the gear case 34, a port side propeller shaft 10 extending in the fore-aft direction of the outboard motor 1, a forward gear 24 and a reverse gear 25 rotatably mounted on the port side propeller shaft 10, a port side dog clutch 26, and a port side propeller The following components, housed in the central axis direction of the shaft 10 and starting from the port side propeller 30 side, are lubricated by the lubricating oil in the port side gearbox 36: a spring (not shown), a cross pin (not shown), a port side shift plunger 38a, and a port side shift cam 32 (shown in Figure 4) which is positioned within a support cylinder (not shown) perpendicular to the front end of the port side shift plunger 38a and in contact with it. Furthermore, an oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil in the port side gearbox 36 are provided at desired positions in the port side gearbox 36.

[0032] Furthermore, the starboard pinion gear 23, the starboard propeller shaft 11 extending in the forward and rearward direction of the outboard motor 1, the reverse gear 28 and forward gear 27 rotatably mounted on the starboard propeller shaft 11, the starboard dog clutch 29, and the spring (not shown), cross pin (not shown), starboard shift plunger 38b, and the shift cam 33 (shown in Figure 4) positioned in a support cylinder (not shown) perpendicular to the front end of the starboard shift plunger 38b and in contact with it, from the starboard propeller 31 side, are all lubricated by the lubricating oil in the starboard gearbox 37. Furthermore, an oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil in the starboard gearbox 37 are provided at desired positions on the starboard gearbox 37.

[0033] Furthermore, in each outboard motor described below, the dog clutches located between the forward and reverse gears or between the reverse gear and the forward gears are positioned similarly to the port and starboard dog clutches 26 and 29 on the port and starboard sides of the outboard motor 1 described above. They are arranged to selectively engage between the forward and reverse gears or between the reverse and forward gears in response to the shift operation, thereby switching the connection between the forward and reverse gears or between the reverse and forward gears to the respective propeller shafts on the port and starboard sides. Therefore, a detailed explanation of the purpose of the dog clutches in each outboard motor described below will be omitted.

[0034] The central axis of the first bevel angular gear 19, which rotates coaxially with the drive shaft 6, and the central axis of the second bevel angular gear 20, which rotates coaxially with the port side driven shaft 7, as well as the central axis of the first bevel angular gear 19, which rotates coaxially with the drive shaft 6, and the central axis of the third bevel angular gear 21, which rotates coaxially with the starboard side driven shaft 8, are connected at an oblique angle rather than in a straight line. Therefore, instead of bevel gears that are connected in a cross shape, bevel angular gears that are connected at an oblique angle are used.

[0035] Next, the shift mechanism 14 will be explained with reference to Figure 4. The shift mechanism 14 will be explained using, in principle, a conventional plunger shift system (rod cam) used in outboard motors as an example. However, the plunger shift system may also be a plunger shift system using a rotating cam, or other shift mechanisms such as a forced shift mechanism may be used.

[0036] In the outboard motor 1, the lowest stepped portion of the port side shift cam (rod cam) 32 is connected to the lower end of the port side push-pull flexible inner cable 44a, and the highest stepped portion of the starboard side shift cam (rod cam) 33 is connected to the lower end of the starboard side push-pull flexible inner cable 44b. Therefore, the port side shift cam 32 and the starboard side shift cam 33 are arranged in a state where they can slide in opposite directions within a support cylinder (not shown).

[0037] The shift cams 32 and 33 on the port and starboard sides are preferably identical in shape and dimensions, and are positioned in opposite directions in the support cylinder (not shown) inside the port side gearbox 36 and the support cylinder (not shown) inside the starboard side gearbox 37. Furthermore, cylindrical mounting holes (not shown) are preferably provided at both ends of the shift cam in the sliding direction, into which terminal fasteners (such as drums) can be fitted for connecting to the lower ends of the respective push-pull flexible cables 44a and 44b.

[0038] Then, in order to slide the port side shift cam 32, which is mounted in a manner that allows it to slide in a direction perpendicular to the port side shift plunger 38a within a support cylinder (not shown) provided in the port side gearbox 36, as shown in Figure 4, the port side lever shift rod 42a is fixed to the other end of a support shaft 41a that supports the port side gear shift handle 40a at one end and its orientation is changed. The upper end of the port side push-pull flexible inner cable 44a, which has flexibility and slides inside the flexible port side flexible outer case (or port side flexible outer tube) 43a, is connected to the tip of the port side lever shift rod 42a. Furthermore, the upper end of the port side shift cam 32 (the side with the lowest stepped portion) is connected to the lower end of the port side push-pull flexible inner cable 44a.

[0039] Furthermore, in order to slide the starboard shift cam 33, which is mounted in a manner that allows it to slide in a direction perpendicular to the starboard shift plunger 38b within a support cylinder (not shown) provided in the starboard gearbox 37, as shown in Figure 4, the starboard lever shift rod 42b is fixed to one end of a support shaft 41b that supports the starboard gear shift handle 40b at the other end, and its orientation is changed. The upper end of the starboard push-pull flexible inner cable 44b, which has flexibility and slides inside the flexible starboard flexible outer case (or starboard flexible outer tube) 43b, is connected to the tip of the starboard lever shift rod 42b, and the upper end of the port shift cam 33 (the highest stepped portion side) is connected to the lower end of the starboard push-pull flexible inner cable 44b.

[0040] In the aforementioned flexible outer cases 43a and 43b on the port and starboard sides, and the push-pull flexible inner cables 44a and 44b on the port and starboard sides, flexible outer cases and inner cables are used to ensure that the centerlines of the drive shaft 6 and the port side driven shaft 7, and the centerlines of the drive shaft 6 and the starboard side driven shaft 8 are not aligned on the same straight line. Therefore, the ends of the respective lever shift rods 42a and 42b on the port and starboard sides and the upper ends of the respective shift cams 32 and 33 on the port and starboard sides are not connected in a straight line, but rather connected by a detour.

[0041] Furthermore, the flexible outer cases 43a and 43b on the port and starboard sides, and the flexible push-pull flexible inner cables 44a and 44b on the port and starboard sides, which are flexible, may be manufactured by processing a metal such as stainless steel, which has corrosion resistance, into a stranded wire or mesh shape, and then covering the surface with a resin-based material such as fluororesin. In addition, other flexible outer cases and inner cables may be used as long as they are flexible and meet various conditions such as being water-resistant, oil-resistant, and not expanding or contracting in the axial direction.

[0042] Furthermore, in the push-pull flexible inner cable that slides the port and starboard shift cams 32 and 33, respectively, located inside the port side gearbox 36 formed inside the port side lower case 34a and inside the starboard side gearbox 37 formed inside the starboard side lower case 34b, the push-pull flexible inner cable may be replaced with a corrosion-resistant metal rod or metal plate. In the case of a push-pull shift rod made of a metal rod or metal plate, the central axis of the drive shaft 6 and the central axes of the port side driven shaft 7 and the starboard side driven shaft 8 are not aligned on the same straight line, so the metal rod or metal plate is manufactured by bending it. Furthermore, the push-pull flexible inner cables on the port and starboard sides, which are made of metal rods or metal plates that allow the respective shift cams 32 and 33 on the port and starboard sides to slide, should be designed and manufactured so that the same parts can be used for both sides.

[0043] Then, when moving the hull 200 forward, the shift mechanism 14 is operated to move both the port side gear shift handle 40a and the starboard side gear shift handle 40b forward, for example (to the positions of the port side and starboard side gear shift handles 40a and 40b shown in Figure 4), causing the lowest forward position stepped portion of the upper part of the port side shift cam 32 located in the port side gearbox 36 to be in the same position as the port side shift plunger 38a, and the port side propeller shaft 10, which is built into the port side, is moved toward the lowest forward position stepped portion in the direction of the central axis of the port side Due to the repulsive force of the side springs, the port side shift plunger 38a and the port side dock clutch 26 slide toward the forward gear 24 located in front of the port side dock clutch 26, causing the port side dock clutch 26 to engage with the forward gear 24, the power of the forward gear 24 to be transmitted to the port side dock clutch 26, and further, the power of the port side dock clutch 26 to be transmitted to the port side propeller shaft 10 via the cross pin, and finally the port side propeller 30 rotates to the left to obtain thrust that moves the hull 200 forward.

[0044] At the same time, the highest forward step portion of the upper part of the starboard shift cam 33 located in the starboard gearbox 37 becomes the same position as the starboard shift plunger 38b, causing the starboard shift plunger 38b to compress the port spring built into the central axis direction of the starboard propeller shaft 11, thereby engaging the starboard shift plunger 38b and the starboard dog clutch 29, and the starboard dog clutch The starboard side dock clutch 29 slides toward the forward gear 27 located aft, and the starboard side dock clutch 29 engages with the forward gear 27. The power of the forward gear 27 is transmitted to the starboard side dock clutch 29, and further, the power of the starboard side dock clutch 29 is transmitted to the starboard side propeller shaft 11 via a cross pin. As a result, the starboard side propeller 31 rotates clockwise to obtain thrust, which causes the hull to move forward.

[0045] When moving the hull in reverse, the shift mechanism 14 is operated to move both the port side gear shift handle 40a and the starboard side gear shift handle 40b to the reverse position. The highest reverse position step at the bottom of the port side shift cam 32 located in the port side gearbox 36 compresses a spring built into the port side propeller shaft 10 in the direction of the central axis. This causes the port side shift plunger 38a and the port side dock clutch 26 to slide towards the reverse gear 25 located behind the port side dock clutch 26. The port side dock clutch 26 engages with the reverse gear 25, and the power from the reverse gear 25 is transmitted to the port side propeller shaft 10 via the cross pin. Finally, the port side propeller 30 rotates to the right, generating thrust that causes the hull to move in reverse.

[0046] At the same time, the starboard shift plunger 38b and the starboard dock clutch 29 slide toward the reverse gear 28 located in front of the starboard dock clutch 29 due to the repulsive force of the starboard spring built into the central axis direction of the starboard propeller shaft 11 toward the lowest reverse position stepped portion at the bottom of the starboard shift cam 33 located in the starboard gearbox 37. The starboard dock clutch 29 engages with the reverse gear 28, and the power of the reverse gear 28 is transmitted to the starboard propeller shaft 11 via the cross pin, ultimately causing the starboard propeller 31 to rotate counterclockwise to obtain thrust that moves the hull backward.

[0047] Furthermore, the neutral position stepped portion in the middle of the port side shift cam 32 and the neutral position stepped portion in the middle of the starboard side shift cam 33 are set to an intermediate height between the forward position stepped portion and the reverse position stepped portion. Then, the neutral position stepped portion of the port side shift cam 32, the neutral position stepped portion of the starboard side shift cam 33, and the biasing force of the springs on the port side and starboard side, which are built into the central axis direction of the port side propeller shaft 10 and the starboard side propeller shaft 11, respectively, cause the port side and starboard side dock clutches 26 and 29 to stop in a position where they do not engage with either the forward gear or the reverse gear, and thus do not engage with the port side propeller 30 and the starboard side propeller 31, thereby stopping the hull.

[0048] Furthermore, the aforementioned power transmission system, through the rotation of the port-side driven shaft 7 and the starboard-side driven shaft 8 rotating in the same direction, ultimately causes the port-side propeller 30 to rotate counterclockwise to the left and the starboard-side propeller 31 to rotate clockwise to the right via the port-side propeller shaft 10 and the starboard-side propeller shaft 11. In order to achieve this, the forward gear 24 located in the port-side gearbox 36 has its teeth facing rearward in front of the port-side dog clutch 26, and the forward gear 27 located in the starboard-side gearbox 37 has its teeth facing forward behind the starboard-side dog clutch 29.

[0049] The port side gear shift handle 40a and the starboard side gear shift handle 40b, which are attached to the support shafts 41a and 41b, may be positioned at a desired location on the outboard motor 1 (for example, on the front of the engine holder 16 or on the tiller handle attached to the outboard motor 1), or on the cockpit side of the hull, together with the respective support shafts 41a and 41b.

[0050] Next, the water pump and each cooling water channel will be explained based on Figure 5. The water pump 18 rotates when an impeller (not shown) located inside the water pump 18 is driven by a drive shaft 6. Cooling water intake ports 51 for pumping water from the navigation area by the rotation of the impeller constituting the water pump 18 are provided as openings on the lower side of the port side gear case 34a and the lower side of the starboard side gear case 34b, as shown in Figures 1, 2, and 5.

[0051] Then, the water intake ports 51 of the port side gear case 34a and the starboard side gear case 34b are connected to the water pump 18 by the upper and lower port side cooling water passages 52a and upper and lower starboard side cooling water passages 52b shown in Figure 5. As the impeller constituting the water pump 18 rotates, cooling water is pumped up from each cooling water intake port 51 through both port side cooling water passages 52a and both starboard side cooling water passages 52b. Furthermore, the cooling water is supplied to the engine 5 side by the upper cooling water passage 53 that connects the water pump 18 to the engine 5 side, thereby cooling the engine 5. Note that the position and number of openings of the cooling water intake ports 51 shown in Figure 1 are not limited, but a position and number of openings that allow for efficient water intake are desirable.

[0052] Furthermore, in addition to the water pump 18, auxiliary water pumps 18a and 18b may be provided on the port side driven shaft 7 and the starboard side driven shaft 8 shown in Figure 1, respectively, above the stern bottom surface, as shown in Figure 5. Each of the auxiliary water pumps 18a and 18b shown in Figure 5 is located between the upper and lower port side cooling water channels 52a and the upper and lower starboard side cooling water channels 52b, and is located in the water when the engine is in neutral or when the gear is engaged with the forward or reverse gear and the engine is idling, and is located above the stern bottom surface when the hull is planing. By providing auxiliary water pumps 18a and 18b on the port side driven shaft 7 and the starboard side driven shaft 8, respectively, in addition to the water pump 18, a sufficient amount of cooling water for cooling the engine 5 can be secured.

[0053] Furthermore, the cooling water pumped up from each cooling water intake 51 by the respective auxiliary water pumps 18a and 18b is pressurized and sent to the upper water pump 18, and the supplied cooling water is further pressurized and sent to the engine 5 side from the upper cooling water passage 53 by the water pump 18 to cool the engine 5.

[0054] Furthermore, while the cooling water pumped up by each of the auxiliary water pumps 18a and 18b is mainly sent under pressure to the water pump 18, some of the cooling water may not be sent under pressure to the water pump 18. Instead, as shown in Figure 5, the auxiliary water pumps 18a and 18b and the upper cooling water channel 53 are connected by the port side bypass channel 54a and the starboard side bypass channel 54b, and the cooling water may be sent to the upper cooling water channel 53 via the port side bypass channel 54a and the starboard side bypass channel 54b.

[0055] In cases where auxiliary water pumps 18a and 18b are provided on the port side driven shaft 7 and the starboard side driven shaft 8, respectively, the water pump 18 may be positioned above the upper gearbox 35, which is close to the engine 5. Furthermore, if the discharge from only the auxiliary water pumps 18a and 18b exceeds the supply capacity of cooling water to cool the engine 5, a cooling method without the water pump 18 can also be considered.

[0056] Next, the rotation stop mechanism will be explained with reference to Figure 6. In order to change the direction of the ship's bow within a narrow range, generating thrust for forward (or backward) movement from the port side propeller 30 and thrust for backward (or forward) movement from the starboard side propeller 31 allows the ship's bow to swing within a narrow range, but at the same time, it also generates a force that rotates the outboard motor 1 around the pivot shaft.

[0057] Therefore, as a countermeasure, as shown in the rotation stop mechanism 55 in Figure 6, a hydraulic steering path is constructed by connecting, for example, a helm pump 56, which is installed in the driver's seat of the hull and driven by a steering handle, with the hydraulic fluid inlets and outlets 58a and 58b of a passive steering cylinder 57 located and fixed at the stern, using a high-pressure resin hose. On-off valves 59a and 59b that shut off the hydraulic fluid path are provided, for example, at the hydraulic fluid inlets and outlets 58a and 58b at both ends of the passive steering cylinder 57 body. The two on-off valves 59a and 59b are then linked together, so that when the two on-off valves 59a and 59b are closed, the hydraulic fluid is trapped inside the passive steering cylinder 57, and the force that rotates the outboard motor 1 is stopped by the trapped hydraulic fluid, thereby fixing and holding the outboard motor 1 to the hull.

[0058] Alternatively, the outboard motor body may be equipped with a braking mechanism (not shown) to stop the rotation of the outboard motor 1. For example, the accelerator grip body of the tiller handle may be equipped with a lever-shaped brake handle that constitutes a mechanical handbrake mechanism used as a brake device for bicycles, etc. The lever-shaped brake handle and a brake shoe that tightens on the outer surface of a drum fixed on the same centerline as the pivot shaft to brake rotation are connected by a flexible wire. When a force is generated that rotates the outboard motor 1 in the circumferential direction around the central axis of the pivot shaft, the lever-shaped brake handle provided on the accelerator grip body is gripped to brake the force that rotates the outboard motor 1, while the rotational speed of the power source is adjusted by the accelerator grip.

[0059] In the power transmission system described in the above embodiment, the drive shaft 6, the port-side driven shaft 7 that drives the port-side propeller shaft 10, the starboard-side driven shaft 8 that drives the starboard-side propeller shaft 11, and the arrangement of bearings for supporting the port-side propeller shaft 10 and the starboard-side propeller shaft 11, etc., should be handled in the same way as in conventional outboard motors, and the decision should be made after considering cost and necessity. Furthermore, in the case of each pinion gear, bevel angular gear, forward gear, reverse gear, etc., the manufacturing and assembly methods should be the same as in conventional outboard motors, for example, by machining the shaft with steps or splines, and further, by cutting an inner groove in the shaft so that each pinion gear, bevel angular gear, etc. can be fixed to the mounting position set on the shaft, and an E-ring should be fitted into the inner groove to fix it.

[0060] Next, we will describe the anticavitation plate with reference to Figures 7 and 8. The anti-cavitation plate 600 is installed above the port propeller 30, located below the port gear case 34a, and the starboard propeller 31, located below the starboard gear case 34b, in a plane approximately parallel to the water surface, to prevent the propeller from drawing in air above the propeller position at high rotational speeds and causing cavitation.

[0061] When the aforementioned single-unit, dual-shaft outboard motor 1 is mounted in the center of the transom board (stern plate) of a hull whose bottom forms a V shape, it is preferable to position the outboard motor 1 such that the plane of the port side anti-cavitation plate 600L located above the port side propeller 30 and the plane of the starboard side anti-cavitation plate 600R located above the starboard side propeller 31 are parallel to the respective stern bottom surfaces on the port and starboard sides that form the V shape. However, the V-angle of the stern bottom of a hull varies depending on the manufacturer of the hull and is not constant. Therefore, it is preferable to set an average V-angle of the stern bottom of various hulls as a standard and integrally mold the outboard motor 1 to form a parallel plane with the standardized stern bottom surface.

[0062] Then, the port side anti-cavitation plate 600L, which is provided at a predetermined position on the port side gear case 34a (shown in Figure 7), is attached to the port side gear case 34a in such a manner that the amount of rotation can be adjusted in the circumferential direction around the rotation centerline, with the rotation centerline being the longitudinal direction perpendicular to the port side driven shaft 7 that extends downward inside the port side gear case 34a. It is even better to attach the inch cavitation plate 600R to the starboard gear case 34b in a manner that allows for adjustment of the amount of rotation in the circumferential direction, with the rotational centerline being the longitudinal direction perpendicular to the starboard driven shaft 8 that extends downward within the starboard gear case 34b, and to position it so that it forms parallel surfaces to the respective stern bottom surfaces on the port and starboard sides that form a V shape.

[0063] Furthermore, the anticavitation plates 600L and 600R on the port and starboard sides are configured such that they can be mounted in a manner that allows for adjustment of the amount of rotation in the circumferential direction around the rotation centerline of the starboard gear case 34a and the starboard gear case 34b. As shown in Figures 7 and 8 (when the anticavitation plate 600L is mounted on the port gear case 34a), the anticavitation plates 600L and 600R on the port and starboard sides are composed of a wide anticavitation plate 60a and a narrow anticavitation plate 60b.

[0064] Furthermore, in order to attach the port side gear case 34a and the starboard side gear case 34b, respectively, to the port side and starboard side anti-cavitation plates 600L and 600R in a manner that allows for adjustment of the amount of rotation in the circumferential direction around the rotation centerline, female threads 64 are screwed into the front and rear portions of the port side gear case 34a and the starboard side gear case 34b, respectively, so that the centerline of the female threads 64 is aligned with the rotation centerline and male threads 63 are screwed into them. In addition, male screw holes 65 are provided in the front and rear portions of the wide-type anti-cavitation plate 60a and the narrow-type anti-cavitation plate 60b, respectively, for inserting male threads 63 having an opening centerline on the rotation centerline.

[0065] Furthermore, at the mounting portions of the port side gear case 34a and the starboard side gear case 34b to which the port side and starboard side anti-cavitation plates 600L and 600R are attached, as shown in the port side gear case 34a shown as an example in Figure 8, the surface shape of the mounting portion 61a provided on the left side of the port side gear case 34a and the starboard side gear case 34b, and the surface shape of the mounting portion 61b provided on the right side of the port side gear case 34a and the starboard side gear case 34b, are formed into a protruding shape that partially includes a substantially ellipsoidal shape centered on the rotational centerline of the port side gear case 34a and the starboard side gear case 34b, respectively.

[0066] Furthermore, the back surface 60as of the wide-type anti-cavitation plate 60a, which is attached to the mounting portion 61a and mounting portion 61b provided on the port-side gear case 34a and the starboard-side gear case 34b, and the back surface 60bs of the narrow-type anti-cavitation plate 60b are also formed into a recessed shape that partially includes a substantially ellipsoidal shape.

[0067] Then, the back side 60as of the wide anti-cavitation plate 60a, which forms a recessed shape, is attached to the protruding mounting portion 61a provided on the left side of the port side gear case 34a, and the back side 60bs of the narrow anti-cavitation plate 60b, which forms a recessed shape, is attached to the protruding mounting portion 61b provided on the right side of the port side gear case 34a. The male screws 63 are then screwed into the female screws 64 sides of the wide anti-cavitation plate 60a and the narrow anti-cavitation plate 60b through the male screw holes 65 that are opened in the front and rear parts of the wide and narrow anti-cavitation plates 60b, respectively, thereby integrating the port side anti-cavitation plate 600L, which is composed of the wide anti-cavitation plate 60a and the narrow anti-cavitation plate 60b, with the port side gear case 34a.

[0068] Furthermore, in the starboard gear case 34b, the starboard anti-cavitation plate 600R, which consists of a wide anti-cavitation plate 60a and a narrow anti-cavitation plate 60b, is integrated into the starboard gear case 34b by the same procedure as when the port anti-cavitation plate 60l is integrated into the port gear case 34a.

[0069] After integrating the wide anti-cavitation plate 60a and the narrow anti-cavitation plate 60b into the port side gear case 34a using the respective male screws 63, the flat surfaces of the integrated port side anti-cavitation plate 600L are positioned so that they form parallel surfaces to the V-shaped stern bottom surface on the port side, thereby securely fixing them together.

[0070] Then, the back side 60bs of the narrow anti-cavitation plate 60b is attached to the mounting portion 61a on the left side of the starboard gear case 34b, and the back side 60bs of the wide anti-cavitation plate 60a is attached to the mounting portion 61b on the right side of the starboard gear case 34b. The narrow anti-cavitation plate 60b and the wide anti-cavitation plate 60a are then integrated using male screws 63, and the flat surfaces of the integrated port side anti-cavitation plate 600R are positioned to form parallel surfaces with the V-shaped stern bottom surface on the starboard side, thereby securely fixing them together.

[0071] As described above, a wide anti-cavitation plate 60a is attached to the mounting portion 61a on the left side of the port side gear case 34a, and a narrow anti-cavitation plate 60b is attached to the mounting portion 61b on the right side of the port side gear case 34a, and the male screws 63 are screwed into the female screws 64 to attach them.

[0072] Furthermore, a narrow anti-cavitation plate 60b is attached to the mounting portion 61a on the left side of the starboard gear case 34b, and a wide anti-cavitation plate 60a is attached to the mounting portion 61b on the right side of the starboard gear case 34b, and the male screws 63 are screwed into the female screws 64 to attach them.

[0073] Therefore, it is preferable to design and manufacture the wide-type anti-cavitation plate 60a and the narrow-type anti-cavitation plate 60b so that they can be used as common parts for both the port-side gear case 34a and the starboard-side gear case 34b, so that the wide-type anti-cavitation plate 60a can be attached to the port-side gear case 34a, and the wide-type anti-cavitation plate 60a can be attached to the mounting portion 61b on the right side of the starboard-side gear case 34b, and the narrow-type anti-cavitation plate 60b can be attached to the mounting portion 61a on the left side of the starboard-side gear case 34b.

[0074] Furthermore, between the surface of the mounting portion 61a and the back surface of the wide-type anti-cavitation plate 60a that contacts the mounting portion 61a, and between the surface of the mounting portion 61b and the back surface of the narrow-type anti-cavitation plate 60b that contacts the mounting portion 61b, cushioning material (not shown), such as rubber or flexible plastic, may be attached (or interposed) on one side to prevent the anti-cavitation plates 600L and 600R on the port and starboard sides from shifting position.

[0075] If the port and starboard anticavitation plates 600L and 600R are manufactured in such a way that their rotational range can be adjusted circumferentially around their respective pivot centers in the fore-aft direction, then even when the outboard motor 1 is mounted on a hull with different V angles, the port and starboard anticavitation plates 600L and 600R can be mounted on the gear cases 34a and 34b so as to form a plane parallel to the stern bottom surface, and the port and starboard anticavitation plates 600L and 600R can be positioned so as to form a plane parallel to the water flow that flows out forcefully from the stern bottom surface on the port and starboard sides of the hull.

[0076] Furthermore, since the anti-cavitation plates 600L and 600R on the port side and the right bank side are composed of a wide anti-cavitation plate 60a and a narrow anti-cavitation plate 60b, and are integrated by male screws 63, even if the anti-cavitation plates 600L and 600R on the port side or the starboard side are damaged, the outboard motor 1 can be reused by replacing either the wide anti-cavitation plate 60a or the narrow anti-cavitation plate 60b, or both anti-cavitation plates 60a and 60b, in a short time.

[0077] Furthermore, the transom height of the outboard motor 1 described above is the distance between the plane containing the rotational centerline of the port side anti-cavitation plate 600L integrated with the port side gear case 34a and the rotational centerline of the starboard side anti-cavitation plate 600R integrated with the starboard side gear case 34b, and the inner surface of the clamp bracket that attaches the outboard motor 1 to the ship.

[0078] In a method of attaching anti-cavitation plates 600L and 600R to the respective gear cases 34a and 34b on the port and starboard sides, respectively, in a manner that allows for circumferential rotational adjustment, if a conventional single-shaft outboard motor with an integrated anti-cavitation plate on the gear case side is used in a V-shaped hull, such as mounting two motors on the port and starboard sides of the transom board, the anti-cavitation plates can be attached to the gear case side so as to form a plane parallel to the stern bottom surface, even when mounted on the port and starboard sides of the hull.

[0079] Furthermore, in the aforementioned single-engine, dual-shaft outboard motor 1, the power transmission system that uses one engine 5 to rotate both the port side propeller 30 and the starboard side propeller 31 outwards to propel the hull forward, and also to rotate both the port side propeller 30 and the starboard side propeller 31 inwards to propel the hull backward, is described in particular. Accordingly, some descriptions and diagrams of other mechanisms necessary for the outboard motor 1 have been omitted. For example, in the exhaust path from the engine to the propeller boss, and in various mechanisms such as the steering friction mechanism and tilt mechanism, which are necessary for the outboard motor 1, existing mechanisms in outboard motors can be utilized.

[0080] Furthermore, the shift mechanism 14 described above allows the outboard motor 1 of the present invention to move forward by, for example, tilting both the port and starboard gear shift handles 40a and 40b forward, which are pushed down by the port and starboard shift cams 32 and 33. This causes the port and starboard dog clutches 26 and 29 to engage with the port and starboard forward gears 24 and 27. When viewed from the rear of the outboard motor 1, the port propeller 30 attached to the port propeller shaft 10 rotates to the left, and the starboard propeller 31 attached to the starboard propeller shaft 11 rotates to the right, thereby propelling the hull forward. The power transmission unit generates thrust to move the hull backward, and by tilting both the port and starboard gear shift handles 40a and 40b to the reverse side, the port and starboard shift cams 32 and 33 are raised, causing the port and starboard dog clutches 26 and 29 to engage with the reverse gears 25 and 28. When viewed from the rear of the outboard motor 1, the port propeller 30 attached to the port propeller shaft 10 rotates to the right, and the starboard propeller 31 attached to the starboard propeller shaft 11 rotates to the left, thereby generating thrust to move the hull backward.

[0081] Because of the power transmission system described above, the port propeller 30 and the starboard propeller 31 rotate in opposite directions, canceling out lateral pressure (counter torque), which improves the straight-line stability of the hull and prevents the hull from tilting due to reaction forces. Therefore, because the hull can not tilt, it is possible to shape the hull into a narrower form, which reduces resistance with the water surface and increases the speed of the hull.

[0082] Furthermore, since the outboard motor 1 is a single-engine, two-shaft outboard motor 1 having one engine 5 and two shafts, a port side propeller shaft 10 and a starboard side propeller shaft 11, the port side dog clutch 26 is engaged with the forward gear 24 (or reverse gear 25) to generate thrust for forward (reverse) movement of the port side propeller 30, and the starboard side dog clutch 29 is engaged with the reverse gear 28 (or forward gear 27) to generate thrust for reverse (forward) movement of the starboard side propeller 31. This allows the bow of the hull to be turned to the right (or left) within a narrow range, and since a single outboard motor can change the direction of the bow within a narrow range, similar to a twin outboard motor, it facilitates docking and undocking of the hull.

[0083] Furthermore, the port side propeller 30 and the starboard side propeller 31 may be rotated inward relative to each other to move the hull forward, and further, they may be rotated outward relative to each other to move the hull backward.

[0084] In the outboard motor 1 described above, the drive shaft is positioned so as to be approximately perpendicular to the water surface. Therefore, the engine connected to the drive shaft is not limited to single-cylinder engines, but can also be combined with inline four-cylinder engines, large-displacement V6, V8, V12, and other high-output multi-cylinder engines with longer crankshafts that are approximately perpendicular to the water surface. Furthermore, since exhaust gas can be discharged into the water through the exhaust ports of the propeller boss on the port side propeller 30 and the propeller boss on the starboard side propeller 31, exhaust efficiency is increased, and even in outboard motors equipped with large-displacement, high-output engines, high output can be secured in the frequently used medium to high rotation range.

[0085] Furthermore, although a detailed explanation is omitted regarding the exhaust path of the outboard motor 1, the carrier body 3 that constitutes the lower unit 4 contains an oil case (not shown) that stores oil for lubricating and cooling the engine, and an exhaust pipe (not shown) that passes through a hollow section extending vertically through the oil case, with a muffler (not shown) connected to its end.

[0086] The exhaust gas discharged into the carrier body 3 passes through the carrier body 3 and is then discharged into the gear case 34. Further discharged into the port side gear case 34a, which is an integral part of the gear case 34 and extends diagonally downward on the port side, and into the starboard side gear case 34b, which is an integral part of the gear case 34 and extends diagonally downward on the starboard side. Finally, it is discharged into the water within the navigation area from the central part (boss section) of the port side propeller 30 and the starboard side propeller 31.

[0087] Therefore, exhaust gas can be discharged from the central part (boss portion) of the port side propeller 30 and the starboard side propeller 31, thereby increasing exhaust efficiency and enabling the engine to rotate at higher speeds. However, increased exhaust efficiency may lead to a decrease in exhaust pressure in the exhaust path at low to medium speeds, potentially resulting in insufficient torque. To address this, a control valve is provided in either the port side gear case 34a, which is an integral part of the port side gear case 34 extended diagonally downward on the port side, or the starboard side gear case 34b, which is an integral part of the gear case 34 extended diagonally downward on the starboard side, to adjust the flow rate of exhaust gas circulating within the gear case 34 and control the exhaust pressure. By limiting the flow rate based on signals detected from an exhaust pressure sensor or engine speed, torque can be ensured at low to medium speeds. By releasing the flow rate restriction, exhaust efficiency can be increased at high rotational speeds, ensuring sufficient power at high rotational speeds.

[0088] As mentioned above, outboard motor 1 only requires one power source. Furthermore, because it has one power source and two shafts, one on the port side and one on the starboard side, it is possible to secure a large propeller area and increase the output of the outboard motor. In addition, although it has two shafts, one on the port side and one on the starboard side, it only requires one power source, which simplifies the maintenance of the prime mover and reduces the overall weight of the hull. Moreover, rotating the port side propeller and the starboard side propeller in opposite directions cancels out the lateral pressure (counter torque), improving straight-line stability and increasing the speed of the hull. Also, rotating the port side propeller and the starboard side propeller in the same direction allows the bow of the hull to swing to the right (or left) within a narrow range, which improves stability during steering, such as making docking and undocking easier.

[0089] Furthermore, instead of an engine, an electric motor may be used as the power source 5 in the outboard motor 1. If an electric motor is used, the engine holder 16 shown in Figure 1 is replaced with a motor holder, the electric motor is installed on the motor holder, the drive shaft is connected to the rotating output shaft of the electric motor, and a first bevel angular 19, which is located in the upper gearbox 35 and rotates coaxially with the drive shaft 6, a second bevel angular 20 which is inclined to connect with the first bevel angular 19, and a third bevel angular 21 which is inclined to connect with the first bevel angular 19 are all constantly meshed to form a two-way power transmission mechanism 9. The power transmission mechanism from the two-way power transmission mechanism 9 to the left and right propeller shafts employs a power transmission mechanism that is substantially the same as that of the outboard motor 1.

[0090] When an electric motor is used, the electric motor can be easily switched between forward and reverse rotation by using a changeover switch that switches the direction of the current flowing to the electric motor. In the port side gear mechanism 12 located in the port side gearbox 36, a pinion gear 22 that rotates coaxially with the port side driven shaft 7 and a port side driven gear located in the port side gearbox 36 and fixed to the port side propeller shaft 10 extending in the fore-and-aft direction of the electric outboard motor 1E with its tooth surface facing rear are constantly meshed and connected. In the starboard side gear mechanism 13 located in the starboard side gearbox 37, a pinion gear 23 that rotates coaxially with the starboard side driven shaft 8 and a starboard side driven gear located in the starboard side gearbox 37 and fixed to the starboard side propeller shaft 11 extending in the fore-and-aft direction of the electric outboard motor 1E with its tooth surface facing forward are constantly meshed and connected.

[0091] When the power supply is switched to the forward direction by the aforementioned changeover switch, the electric motor rotates to the right when viewed from above, ultimately causing the port side propeller 30 to rotate counterclockwise (to the left) to move the hull forward, and the starboard side propeller 31 to rotate clockwise (to the right) to move the hull forward. Furthermore, when the power supply is switched to the reverse direction by the aforementioned changeover switch mechanism, the electric motor rotates to the left when viewed from above, ultimately causing the port side propeller 30 to rotate clockwise (to the right) to move the hull backward, and the starboard side propeller 31 to rotate counterclockwise (to the left) to move the hull backward.

[0092] Furthermore, if a port-side driven gear is used in the port-side gear mechanism 12 and a starboard-side driven gear is used in the starboard-side gear mechanism 13, the port-side propeller 30 and the starboard-side propeller 31 will rotate in opposite directions, but they cannot be made to rotate in the same direction, making it impossible to change the bow within a narrow range. Therefore, as with the outboard motor 1, if the port-side gear mechanism 12 and the starboard-side gear mechanism 13 are equipped with a forward gear, a reverse gear, and a dog clutch, respectively, the bow can be changed within a narrow range.

[0093] Furthermore, in another embodiment (not shown), an electric outboard motor 1E is also conceivable, in which electric motors are installed in the port side gearbox 36 (port side motor pod) and the starboard side gearbox 37 (starboard side motor pod), which form an inverted Y shape, a port side propeller 30 that can obtain thrust by rotating counterclockwise (reverse by rotating clockwise) is attached to the output shaft of the port side electric motor, and a starboard side propeller 31 that can obtain thrust by rotating clockwise (reverse by rotating counterclockwise) is attached to the output shaft of the starboard side electric motor, and a power battery, which is the power source, is placed at the head of the outboard motor, and the power battery is connected to the port side electric motor and the starboard side electric motor by connecting cables that electrically connect them, and an on / off switch to stop the power supplied to each electric motor and a reverse switch to reverse the direction of current flow are provided at appropriate points along the connecting cables.

[0094] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 9 to 12. The outboard motor 1J (1JL, 1JR) of this embodiment is equipped with a constant velocity joint 70 at an appropriate point along the drive shaft 6 of the outboard motor 1 shown in Figure 1. The lower unit 4, which includes a port side propeller 30 and a starboard side propeller 31 as shown in Figure 1, is mounted in a manner that allows it to rotate in the port or starboard direction around the rotation centerline F-F in the fore-aft direction, which includes the angular center O of the constant velocity joint 70. Note that there is an outboard motor 1JL for port use and an outboard motor 1JR for starboard use, but the outboard motor 1JR is not shown.

[0095] In the outboard motor 1J shown in Figure 9, the drive shaft 6 in the outboard motor 1 shown in Figure 1 is replaced by the drive shaft 71 shown in Figure 9. The drive shaft 71 is composed of an upper drive shaft 71a and a lower drive shaft 71b, and a constant velocity joint 70 is provided to connect the lower end of the upper drive shaft 71a and the upper end of the lower drive shaft 71b. Aside from the presence of the constant velocity joint 70, the power transmission system is substantially the same as that of the outboard motor 1 (Figure 1) described above. Therefore, for the power transmission system below the lower drive shaft 71b that connects to the lower end of the constant velocity joint 70, refer to the detailed description and drawings of the outboard motor 1 described above, unless otherwise specified. Any other parts that differ are described below.

[0096] In the case of outboard motor 1JL, where the outboard motor 1J is mounted on the port side of the transom board as shown in Figure 9, the port side driven shaft 7 and port side propeller shaft 10, which constitute the outboard motor 1 shown in Figure 1, are located on the outside of the hull, while the starboard side driven shaft 8 and starboard side propeller shaft 11, which constitute the outboard motor 1, are located on the inside of the hull. In the case of outboard motor 1JR, where the outboard motor 1J is mounted on the starboard side of the transom board, the port side driven shaft 7 and port side propeller shaft 10, which constitute the outboard motor 1 shown in Figure 1, are located on the inside of the hull, while the starboard side driven shaft 8 and starboard side propeller shaft 11, which constitute the outboard motor 1, are located on the outside of the hull.

[0097] Therefore, in the case of outboard motor 1JL, where outboard motor 1J is mounted on the port side, and in the case of outboard motor 1JR, where it is mounted on the starboard side, the outside and inside are reversed. In the following explanation, in the case of outboard motor 1JL, where outboard motor 1J is mounted on the port side of the transom board, for example, the port side driven shaft 7 shown in Figure 1 will be referred to as one-side driven shaft 7J, and the starboard side driven shaft 8 will be referred to as the other-side driven shaft 8J. Similarly, in the case of outboard motor 1JR, where outboard motor 1J is mounted on the starboard side of the transom board, the port side driven shaft 7 shown in Figure 1 will be referred to as one-side driven shaft 7J, and the starboard side driven shaft 8 will be referred to as the other-side driven shaft 8J.

[0098] The following explanation will be given for the case of outboard motor 1JL, in which the aforementioned outboard motor 1J is mounted on the port side of the transom board (Figure 9). As described above, the drive shaft 71 in the outboard motor 1JL is composed of an upper drive shaft 71a and a lower drive shaft 71b, and a constant velocity joint 70 is provided between the lower end of the upper drive shaft 71a and the upper end of the lower drive shaft 71b, connecting the upper drive shaft 71a and the lower drive shaft 71b.

[0099] The constant velocity joint 70 is a type of universal joint, a component for transmitting rotational motion, which can transmit the output from the upper main drive shaft 71a to the lower main drive shaft 71b at a constant speed, even when there is an operating angle between the upper main drive shaft 71a and the lower main drive shaft 71b. The use of the constant velocity joint 70 is not limited, and other universal joints may be used.

[0100] Furthermore, the constant velocity joint 70, which is provided at an appropriate point along the drive shaft 71, is covered with a flexible boot 72, as shown in Figure 10, using fasteners such as a worm-type hose clamp, to prevent splashing of lubricating oil and to prevent the intrusion of coolant after engine cooling.

[0101] Furthermore, an upper carrier body 73a that covers the upper drive shaft 71a and a lower carrier body 73b that covers the lower drive shaft 71b are provided, and the upper carrier body 73a and the lower carrier body 73b constitute the carrier body 73.

[0102] The rotation center line F-F shown in Figure 10 is defined as a line passing through the angular center O of the constant velocity joint 70 and parallel to the rotation center axes of the propeller shafts 10J and 11J on one and the other sides of the outboard motor 1JL (or, if the rotation center line of the one propeller shaft 10J and the rotation center line of the other propeller shaft 11J are not parallel lines, the center line between the rotation center line of the one propeller shaft 10J and the rotation center line of the other propeller shaft 11J as viewed from above).

[0103] Then, the entire lower unit 4 (the lower carrier body 73b and the gear case 34, which includes one propeller shaft 10J and the other propeller shaft 11J), excluding the upper carrier body 73a fixed to the engine holder 16, is attached to the upper carrier body 73a, which constitutes the carrier body 73, in a manner that allows it to be rotated and adjusted in the port or starboard direction around the rotation center line F-F.

[0104] Furthermore, in terms of mounting, as shown in Figure 10, at a position that coincides with the rotation center line F-F which passes through the angular center O of the constant velocity joint 70 and is parallel to the rotation center line of one propeller shaft 10J and the rotation center line of the other propeller shaft 11J of the outboard motor 1J (if the rotation center lines of one propeller shaft 10J and the rotation center lines of the other propeller shaft 11J are not parallel lines, then the center line of the rotation center line of one propeller shaft 10J and the rotation center line of the other propeller shaft 11J as viewed from above), male screw holes 74 are provided on the front outer part and rear outer part of the upper carrier body 73a side (or lower carrier body 73b side) that constitutes the carrier body 73, and female screws 75 are threaded on the front inner part and rear inner part of the lower carrier body 73b side (or upper carrier body 73a side) that constitutes the carrier body 73.

[0105] Then, the male screws 76 are screwed into the female screws 75 threaded on the lower carrier body 73b through the male screw holes 74 provided on the front outer and rear outer parts of the upper carrier body 73a, thereby integrating the entire lower unit 4, excluding the upper carrier body 73a, with the upper carrier body 73a in a rotatable state. The lower unit rotation adjustment mechanism is formed by the male screw holes 74 provided on the front and rear of the upper carrier body 73a, the male screw holes 74 provided on the front and rear of the lower carrier body 73b, the male screws 76, and the flexible tube-shaped outer cover 78 described later.

[0106] Furthermore, as shown in Figure 11, a flexible tube outer cover 78 (not shown in Figures 9 and 10), such as a bellows-shaped flexible tube outer cover 78, is fitted between the upper carrier body 73a and the lower carrier body 73b to shield the internal space 77 formed within the integrated carrier body 73 from the external space of the atmosphere. This cover is secured, for example, with fasteners such as worm-type hose clamps and bolts, to prevent the release of cooling water and exhaust gas (exhaust noise, etc.) from the internal space 77, as well as to prevent water from entering from the navigation area.

[0107] Furthermore, in the shift mechanism of the single-unit, dual-shaft outboard motor 1J, the shift mechanism (shown in Figure 4) of the outboard motor 1 will be adopted.

[0108] Next, regarding the outboard motor 1J, other parts that differ particularly from the outboard motor 1 (Figure 1) described above, in addition to the constant velocity joint 70, will be explained using Figures 10 to 12. The lower part of the steering pivot shaft (not shown) that constitutes the swivel mechanism of the outboard motor 1J is connected to the upper carrier body 73a side that constitutes the carrier body 73 via one damper mount 79a and the other damper mount 79b, and the upper and lower ends of the flexible tube-shaped outer cover 78 are attached and fixed to the upper carrier body 73a side and the lower carrier body 73b side, respectively, by fasteners such as worm-type hose clamps and bolts. To achieve both, the front to rear portions above the upper carrier body 73a shown in Figure 12, above the rotation center line F-F shown in Figure 10, are designated as the one-side arm base 81a and the other-side arm base 81b, respectively. A one-side damper mount mounting arm 82a is provided that protrudes downward and outward from the one-side arm base 81a, and a one-side mounting portion 80a is provided at the tip of the one-side damper mount mounting arm 82a to which the one-side damper mount 79a is attached.

[0109] Furthermore, a mounting arm 82b for the other damper mount is provided that protrudes downward and outward from the base portion 81b of the other arm, and a mounting portion 80b for attaching the other damper mount 79b is provided at the tip of the mounting arm 82b for the other damper mount.

[0110] The shape of the one damper mount mounting arm 82a and the other damper mount mounting arm 82b is such that, when viewed from the front or rear direction, they gradually widen outwards as they go downwards, resembling a V-shape. Furthermore, the shape is such that the lower unit 4, excluding the upper carrier body 73a, does not come into contact with the lower unit 4 even when it is rotated to its maximum extent in the port or starboard direction around the rotation centerline F-F.

[0111] Alternatively, the one-sided arm base 81a and the other-sided arm base 81b may be provided on the lower surface side of the engine holder 16 (not shown), and the one-sided damper mount mounting arm 82a and the other-sided damper mount mounting arm 82b, which protrude downward from the one-sided arm base 81a and the other-sided arm base 81b, may be integrally molded in a curtain-like manner and provided to cover the exterior cover 78, which is attached and fixed to the upper carrier body 73a side and the lower carrier body 73b side by fasteners such as worm-type hose clamps and bolts.

[0112] Then, the rear end of the one-side damper mount 79a is inserted into the one-side mounting portion 80a and fixed integrally with screws or the like, and further, the rear end of the other-side damper mount 79b is inserted into the other-side mounting portion 80b to which the rear end of the other-side damper mount 79b is attached and fixed integrally with screws or the like.

[0113] Furthermore, in order to integrate the one-side damper mount 79a body and the other-side damper mount 79b body with the one-side mounting portion 80a and the other-side mounting portion 80b, a cover (not shown) is placed over the one-side mounting portion 80a and the other-side mounting portion 80b from the inside or outside, respectively, and the cover is secured with bolts. For the cover, refer to the configuration and mounting method of damper mount covers in conventional outboard motors.

[0114] Furthermore, the male threaded portion on the front end of one damper mount 79a and the male threaded portion on the front end of the other damper mount 79b are inserted into the mounting holes at both ends of a support base plate 84, which has a support portion 83 in the center for supporting the lower part of the steering pivot shaft. Nuts are then screwed onto each male threaded portion to form an integrated structure that supports the lower part of the steering pivot shaft. In addition, a damper is interposed between the support portion 83 and the lower part of the steering pivot shaft for further support.

[0115] Then, after adjusting the rotation of the lower unit 4, excluding the upper carrier body 73a, the upper and lower ends of the exterior cover 78, which is fitted around the carrier body 73 in advance, are fixed to the upper carrier body 73a side and the lower carrier body 73b side, respectively, using fasteners such as worm-type hose clamps and bolts (not shown), as shown in Figure 11.

[0116] The one-side damper mount mounting arm 82a and the other-side damper mount mounting arm 82b are integrally connected to the support base plate 84 in an annular manner with the one-side damper mount 79a and the other-side damper mount 79b interposed between them, and the support portion 83 provided in the center of the support base plate 84 supports the lower part of the steering pivot shaft.

[0117] The outboard motor 1J is positioned on the port or starboard side of the transom board of the hull, and the lower unit 4, excluding the upper carrier body 73a, is rotated to the port or starboard side about the rotation centerline F-F so that the rotation centers of the propellers 30J and 31J on one side and the other side of the outboard motor 1J are located on parallel lines parallel to the V-shaped stern bottom surface, thereby determining the positions of the propellers 30J and 31J on one side and the other side.

[0118] Furthermore, in order to firmly integrate the upper carrier body 73a and the lower carrier body 73b, for example, in the case of the outboard motor 1JL positioned on the port side of the transom board, as shown in Figure 11, a spectacle-shaped torque rod 86 is connected to a torque rod mounting portion 85a with a female thread on one inner surface of the lower part of the upper carrier body 73a and a torque rod mounting portion 85b with a female thread on one inner surface of the upper part of the lower carrier body 73b by male threads.

[0119] Furthermore, the spectacle-shaped torque rod 86 is attached to the torque rod mounting portion 85a on the upper carrier body 73a side and the torque rod mounting portion 85b on the lower carrier body 73b side by male screws. In addition, a torque rod mounting portion 85c with a female screw thread may be provided on the other inner surface of the lower part of the upper carrier body 73a, and a torque rod mounting portion 85d with a female screw thread may be provided on the other inner surface of the upper part of the lower carrier body 73b. By attaching a spectacle-shaped torque rod 86a, which is longer and more curved than the spectacle-shaped torque rod 86, to the upper and lower mounting portions 85c and 85d by male screws, the lower carrier body 73b constituting the lower unit 4 can be more firmly and integrally connected to the upper carrier body 73a side.

[0120] Furthermore, even when the outboard motor 1JR is mounted and fixed to the starboard side of the transom board, it can be connected and coupled even more firmly and integrally by attaching the spectacle-shaped torque rods 86 and 86a, similar to the case where the outboard motor 1JL is mounted to the port side of the transom board as described above.

[0121] Then, the male screws 76, which have been pre-screwed into the female screws 75 threaded on the front and rear of the lower carrier body 73b, are screwed through the male screw holes 74 that have opened on the front and rear of the upper carrier body 73a, thereby integrally connecting and coupling the lower carrier body 73b, which constitutes the lower unit 4, to the upper carrier body 73a.

[0122] In the spectacle-shaped torque rods 86, 86a, and 86b, if the outboard motor 1J is mounted on the port side of the transom board of a hull with a different V-angle at the stern bottom, for example, the distance between the torque rod mounting portion 85a provided on one inner surface of the lower part of the upper carrier body 73a and the torque rod mounting portion 85b provided on one inner surface of the upper part of the lower carrier body 73b will be different. Therefore, several types of torque rods 86, 86a, 86b, etc., will be prepared, each with a different distance between the center point of one annular opening at both ends of the torque rod and the center point of the other annular opening.

[0123] Furthermore, among the several types of torque rods prepared, the rotation range of the lower unit 4, excluding the upper carrier body 73a, is limited by the torque rods in which the distance between the center point of one annular opening and the center point of the other annular opening is set to the maximum and minimum. In addition, when a certain torque rod is used, it is preferable to mark the angle between the stern bottom surface, which forms a V shape, and the horizontal plane on the surface of the torque rod body.

[0124] In the handle portion of the torque rod between one annular opening and the other, it is preferable to form it in a curved shape, as shown in Figure 11. The inner surface of the flexible tube-shaped outer cover 78 comes into contact with the curved handle portion of the torque rod and does not enter the constant velocity joint 70 side, thereby preventing contact with the flexible boot 72 fitted to the constant velocity joint 70 side.

[0125] Then, the upper and lower ends of the exterior cover 78 fitted around the carrier body 73 are fixed to the upper carrier body 73a side and the lower carrier body 73b side, for example, by fasteners such as worm-type hose clamps or screws.

[0126] As described above, by attaching the entire lower unit 4 to the upper carrier body 73a side in a manner that allows it to be rotatably adjusted in the port or starboard direction on the transom board, the entire lower unit 4, excluding the upper carrier body 73a, can be rotatably adjusted in the port or starboard direction. As a result, the rotation centers of one propeller 30J and the other propeller 31J of the outboard motor 1JL can be positioned on parallel lines parallel to the port side stern bottom surface of the transom board in the V-shaped hull, thereby preventing cavitation between the one propeller 30J and the other propeller 31J.

[0127] Furthermore, even in the case of an outboard motor 1JR mounted on the starboard side of the transom board, the outboard motor 1J can be mounted on the transom board in a rotatable and adjustable manner. The rotation centers of one propeller 30J and the other propeller 31J of the outboard motor 1JR can be positioned on parallel lines parallel to the stern bottom surface on the starboard side of the transom board in a V-shaped hull, thereby preventing cavitation between the one propeller 30J and the other propeller 31J.

[0128] Furthermore, as described above, in order to rotate the entire lower unit 4 excluding the upper carrier body 73a, the carrier body 73 is composed of an upper carrier body 73a and a lower carrier body 73b so that it rotates simultaneously. However, the upper carrier body 73a may be formed and manufactured as an integral structure with the lower surface of the engine holder 16, and the lower carrier body 73b may be formed and manufactured as an integral structure with the upper surface of the gear case 34. However, this is not a limitation.

[0129] In the case of outboard motor 1JR, where the outboard motor 1J is mounted on the starboard side of the transom board, the entire lower unit 4, excluding the upper carrier body 73a, is rotated to the starboard side, similar to the case of outboard motor 1JL, where the outboard motor 1J is mounted on the port side of the transom board. This is done so that the rotation centers of one propeller 30J and the other propeller 31J are positioned parallel to the starboard stern bottom surface on the transom board of the hull, which forms a V shape. After this, the lower carrier body 73b, which is positioned on the upper carrier body 73a side, is integrated into the unit. Further details should be referred to in the case of outboard motor 1JL, where the outboard motor 1J is mounted on the port side of the transom board.

[0130] Furthermore, the power source of the outboard motor 1J may include an electric motor. In the case of an internal combustion engine, lubricating oil is applied between parts where metal surfaces directly come into contact, such as between the cylinder and piston, or between the crankshaft and connecting rod, to reduce friction and wear. However, when an electric motor is used, there are no parts where friction and wear are reduced with lubricating oil other than using, for example, bearings sealed with grease in the bearing portion supporting the output shaft. Therefore, it is not necessary to rotate the entire lower unit of the outboard motor 1 in the port or starboard direction using a constant velocity joint. However, in the electric outboard motor 1JE, which employs an electric motor, by providing a constant velocity joint, the entire lower unit can be rotated in the port or starboard direction around the fore-aft rotation center line F-F, which includes the angular center O of the constant velocity joint 70, thereby narrowing the overall width of the electric outboard motor 1JE body.

[0131] (Third embodiment) Next, a third embodiment of the present invention will be described. In the power transmission mechanism of the outboard motor 1 (and outboard motor 1JL) described above (Figures 1 and 9), a first bevel angular bearing rotates coaxially with the drive shaft and is positioned in the upper gearbox with its smaller diameter facing upwards; a second bevel angular bearing is constantly meshed with and connected to the first bevel angular bearing and is positioned in the upper gearbox with its smaller diameter facing upwards; and a third bevel angular bearing is constantly meshed with and connected to the first bevel angular bearing and is positioned in the upper gearbox with its smaller diameter facing upwards. While the power transmission mechanism is configured using two bevel angle fittings, a single-unit, two-shaft outboard motor 1A is also conceivable, which has a power branching transmission mechanism 94 composed of a fourth bevel angle fitting 95 that rotates coaxially with the drive shaft 92 and is positioned in the upper gearbox with its smaller diameter facing upward, and a fifth bevel angle fitting 96 that is constantly meshed with the fourth bevel angle fitting and is obliquely connected to it and is also positioned in the upper gearbox with its smaller diameter facing upward, as shown in Figure 13. This will be described below with reference to the drawings.

[0132] Figure 13 is a rear view showing the power branching transmission system in the single-unit, dual-shaft outboard motor 1A (hereinafter referred to as outboard motor 1A) according to this embodiment. The outboard motor 1A is mounted on the transom board (stern plate) of the hull so as to be rotatable in the vertical and horizontal directions via a steering mechanism (not shown) consisting of a swivel bracket and a clamp bracket.

[0133] This section describes the case where a single outboard motor 1A, a dual-shaft system, is mounted in the center of the transom board. The outboard motor 1A has an engine 5, which is the power source, at its head. The crankshaft 17 of the engine 5 is mounted on top of the engine holder 16, tilted at a certain angle α with respect to the vertical centerline of the outboard motor 1A body. An upper power unit 15a, covered by a cowl 2, is positioned on the engine holder 16. The power source may also include an electric motor.

[0134] Furthermore, in the middle of the lower part of the upper power unit 15a, there is a carrier body 90 which constitutes the lower unit 4. This carrier body 90 contains an oil case (not shown) that stores oil for lubricating and cooling the drive shaft 92 and the engine 5, and an exhaust pipe (not shown) that guides exhaust gas discharged from the engine 5 through a hollow section extending vertically through the oil case, with a muffler (not shown) connected to its end.

[0135] Furthermore, a gear case 91 is arranged at the lower part of the carrier body 90, with the port side gear case 91a extending diagonally downward to the port side and the starboard side gear case 91b extending diagonally downward to the starboard side, forming an integrated gear case 91. The upper power unit 15a and the carrier body 90 and gear case 91 that constitute the lower unit 4 are integrally connected to form the outboard motor 1A. The outboard motor 1A then provides thrust to the hull 200.

[0136] The engine 5, which is the power source, includes the crankshaft 17, which extends inclined with respect to the water surface and in a downward-sloping direction to the port side. The upper end of the drive shaft 92 is connected to the lower part of the crankshaft 17, for example, by a spline fit, and the drive shaft 92 extends inside the carrier body 90 in a downward-sloping direction to the port side.

[0137] Furthermore, the drive shaft 92 has a fourth bevel angular contact screw 95 fixed to it in an upper gearbox 35a that stores lubricating oil, which is formed at an appropriate location midway below the connection point with the crankshaft 17 (either within the carrier body 90 constituting the lower unit 4 or within the gear case 91). The fourth bevel angular contact screw 95 is positioned with its smaller diameter side facing upward relative to the water surface. The fourth bevel angular contact screw 95 and the drive shaft 92 rotate coaxially.

[0138] Furthermore, the lower part of the drive shaft 92 extends downward within the port side gear case 91a, and below the extended drive shaft 92, it coaxially rotates an impeller (not shown) that constitutes the water pump 18a, which is fixedly positioned within the port side gear case 91a.

[0139] Furthermore, the fourth bevel angular bearing 95, positioned in the upper gearbox 35a with its smaller diameter facing upward, and the fifth bevel angular bearing 96, positioned in the upper gearbox 35a with its smaller diameter facing upward, are constantly meshed and connected in an inclined state. In addition, the lower part of the driven shaft 93, which rotates coaxially with the fifth bevel angular bearing 96, extends into the starboard gear case 91b, and below the extended driven shaft 93, it coaxially rotates the impeller (not shown) that constitutes the water pump 18b, which is positioned and fixed inside the starboard gear case 91b. The fourth bevel angular bearing 95 and the fifth bevel angular bearing 96 constitute the power branching transmission mechanism 94.

[0140] In the aforementioned drive shaft 92, the upper portion is the drive shaft and the lower portion is the driven shaft, with the drive shaft and the driven shaft being configured coaxially as a single unit. Therefore, the lower portion will be referred to as the driven shaft 92 below.

[0141] Furthermore, the driven shaft 92 (the portion below the power branching transmission mechanism) extends into the port side gearbox 36a (not shown), which is formed inside the port side gear case 91a, and fixes the port side pinion gear 22 (not shown), which is located inside the port side gearbox 36a, to the lower end of the port side driven shaft 92. The starboard side driven shaft 93 extends into the starboard side gearbox 37a (not shown), which is formed inside the starboard side gear case 91b, and fixes the starboard side pinion gear 23 (not shown), which is located inside the starboard side gearbox 37a, to the lower end of the port side driven shaft 93.

[0142] Furthermore, the arrangement of the port side gearbox 36a (not shown), port side pinion gear 22 (not shown), reverse gear 25 (not shown), and forward gear 24 (not shown) as described above, and the arrangement of the starboard side gearbox 37a (not shown), starboard side pinion gear 23 (not shown), reverse gear 28 (not shown), and forward gear 27 (not shown) as described above, are the same as the arrangement of the starboard side gearbox 37, starboard side pinion gear 23, reverse gear 28, and forward gear 27 in the outboard motor 1 shown in Figure 3, and they are always meshed and operate in the same way. Therefore, the arrangement of the port side gearbox 36a, port side pinion gear 22, reverse gear 25, and forward gear 24, and the arrangement of the starboard side gearbox 37a, starboard side pinion gear 23, reverse gear 28, and forward gear 27, will be based on the starboard side gear mechanism 13 located within the starboard side gearbox 37 in the outboard motor 1 shown in Figure 3.

[0143] In the shift mechanism of the outboard motor 1A, the reverse gear, which is rotatably mounted on the port propeller shaft 10, is positioned in front of the port dog clutch, and the forward gear is positioned aft. Similarly, the reverse gear 28, which is rotatably mounted on the starboard propeller shaft 11, is positioned in front of the starboard dog clutch 29, and the forward gear 27 is positioned aft.

[0144] Therefore, by adopting the starboard shift mechanism, which consists of the starboard gear shift handle 40b and the shift cam 33 that is ultimately connected to the starboard gear shift handle 40b in the shift mechanism used in the outboard motor 1 shown in Figure 4, as the shift mechanism for the port and starboard sides, by tilting both the port gear shift handle 40a and the starboard gear shift handle 40a forward, the left side can be shifted. Each dog clutch on the port and starboard sides engages with the respective forward gears, generating forward thrust for the port and starboard propellers 30 and 31. Additionally, by tilting both the port and starboard gear shift handles 40a to the reverse side, each dog clutch on the port and starboard sides engages with the respective reverse gears, generating backward thrust for the port and starboard propellers 30 and 31.

[0145] Furthermore, the angle α formed by the rotational centerline of the driven shaft 92 and the vertical centerline of the outboard motor 1A body, and the angle β formed by the rotational centerline of the driven shaft 93 and the vertical centerline of the outboard motor 1A body, are set to the same angle (α=β). The driven shafts 92 and 93 are arranged in an inverted V shape downwards from the upper gearbox 35a, with the vertical centerline of the outboard motor 1A body as the centerline.

[0146] The angle α between the rotational centerline of the driven shaft 92 and the vertical centerline of the outboard motor 1A body is determined after considering various conditions, such as the distance between the position of the port side propeller 30 and the position of the starboard side propeller 31, as described later.

[0147] Furthermore, the pitch point P between the fourth bevel angular 95 and the fifth bevel angular 96 is located on the vertical centerline of the outboard motor 1A body as viewed from the front-rear direction, and coincides with a plane containing the rotational centerline of the driven shaft 92 and the rotational centerline of the driven shaft 93. Preferably, this plane is perpendicular to the front-rear direction of the outboard motor 1A body.

[0148] Furthermore, the fourth bevel angular contactor 95 and the fifth bevel angular contactor 96, which are constantly meshed with and obliquely connected to the fourth bevel angular contactor 95, are housed within the upper gearbox 35a and lubricated by the lubricating oil within the upper gearbox 35a. An oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil within the upper gearbox 35a are provided at desired positions in the upper gearbox 35a. In addition, it is conceivable that the fourth bevel angular contactor 95 and the fifth bevel angular contactor 96 be lubricated by sharing the lubrication system with the engine 5, which is the power source.

[0149] The port-side pinion gear 22, fixed to the lower end of the port-side driven shaft 92, is located within the port-side gearbox 36a. A gear mechanism similar to the starboard-side gear mechanism 13 located within the starboard-side gearbox 37 in the outboard motor 1 shown in Figure 3 is located within the port-side gearbox 36a in the outboard motor 1A.

[0150] Then, the port-side propeller 30, which generates thrust that moves forward by rotating counterclockwise, is attached to the port-side propeller shaft 10 driven by the driven shaft 92. When the outboard motor 1A is viewed from above, and the engine 5 is rotating clockwise in the same direction as the engine 5, the hull is moved forward and backward by the same operation as the starboard gear mechanism 13 located in the starboard gearbox 37 of the outboard motor 1 shown in Figure 3.

[0151] Furthermore, the port side gear mechanism located within the port side gearbox 36a of the outboard motor 1A is lubricated by the lubricating oil in the port side gearbox 36a, similar to the starboard side gear mechanism 13 located within the starboard side gearbox 37 of the outboard motor 1 shown in Figure 3. In addition, an oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil in the port side gearbox 36a are provided at desired positions in the port side gearbox 36a.

[0152] Furthermore, the starboard pinion gear 23 supported at the lower end of the driven shaft 93 is located within the starboard gearbox 37a, and a gear mechanism similar to the starboard gear mechanism 13 located within the starboard gearbox 37 in the outboard motor 1 shown in Figure 3 is located within the starboard gearbox 37a in the outboard motor 1A.

[0153] Then, the starboard propeller 31, which generates thrust that moves forward by rotating to the right, is attached to the starboard propeller shaft 11 driven by the driven shaft 93. When the outboard motor 1A is viewed from above, and the engine 5 rotates to the right in the same direction as the engine 5, the hull is moved forward and backward by the same operation as the starboard gear mechanism 13 located in the starboard gearbox 37 of the outboard motor 1 shown in Figure 3.

[0154] Furthermore, the starboard gear mechanism located within the starboard gearbox 37a of the outboard motor 1A is lubricated by the lubricating oil in the starboard gearbox 37a, similar to the starboard gear mechanism 13 located within the starboard gearbox 37 of the outboard motor 1 shown in Figure 3. An oil drain plug (not shown) and an oil level plug (not shown) for changing the lubricating oil in the starboard gearbox 37a are provided at desired positions in the port gearbox 36a.

[0155] Furthermore, cooling water intake ports 51 for drawing up water from the navigation area are provided (not shown) opening on the lower sides of the port side gear case 91a and the starboard side gear case 91b, similar to the cooling water intake port 51 shown in Figure 1. In addition, water pumps 18a and 18b are provided on the port side driven shaft 92 and the starboard side driven shaft 93, respectively. The impeller constituting the water pump 18a is driven by the driven shaft 92, and the impeller constituting the water pump 18b is driven by the driven shaft 93, drawing up water from the navigation area through each cooling water intake port 51 to cool the engine 5.

[0156] The water pumps 18a and 18b may be installed on either the driven shaft 92 or the driven shaft 93, provided that the amount of water pumped by either the driven shaft 92 or the driven shaft 93 is sufficient to cool the engine 5. For the cooling water passages between each cooling water intake 51 and each water pump 18a and 18b, and between each water pump 18a and 18b and the engine 5, please refer to Figure 5.

[0157] As described above, the engine 5 connected to the driven shaft 92 has a crankshaft 17 that forms a certain angle α with respect to the vertical centerline of the outboard motor body, and the engine 5 is positioned and fixed at an angle on the engine holder 16. Therefore, it is suitable for single-cylinder engines, twin-cylinder engines, or electric motors that have a relatively low overall height and narrow overall width.

[0158] The above explanation specifically describes the power distribution mechanism in a single-unit, dual-shaft outboard motor 1A. In the explanation of other mechanisms required for outboard motor 1A besides the power distribution system, such as the anti-cavitation plate 60, please refer to the explanation of the single-unit, dual-shaft outboard motor 1 (Figure 1).

[0159] Furthermore, the transom height of the single-unit, dual-shaft outboard motor 1A is the distance between the inner surface of the clamp bracket that attaches the outboard motor 1A to the transom board of the hull, and the plane containing the rotational centerlines of the port-side anti-cavitation plate 60 and the starboard-side anti-cavitation plate 60, which rotate in the circumferential direction.

[0160] Furthermore, in the aforementioned single-unit, dual-shaft outboard motor 1A, the crankshaft 17 constituting the engine and the driven shaft 92 connected to the crankshaft 17 by spline fitting or the like were extended in the port-down direction. However, an outboard motor 1AA (not shown) with a single-unit, dual-shaft configuration may also be used, in which the crankshaft 17 and the drive shaft 93 connected to the crankshaft 17 by spline fitting or the like are extended in the starboard-down direction, and the driven shaft 92 is also extended in the port-down direction.

[0161] (Modified version of the third embodiment) Next, a modified example of the third embodiment will be described. The outboard motor 1A described above is primarily intended for use as a single unit mounted in the center of the transom board of a hull with a V-shaped bottom, or as a single or multiple unit mounted on a houseboat with a flat bottom. However, it is also conceivable to use an outboard motor 1F, which does not have a power branching transmission system substantially similar to that of the outboard motor 1A, by installing it on the starboard side of the transom board of a hull with a V-shaped bottom, as shown in Figure 14, for use on the starboard side, which will be explained below.

[0162] To use an outboard motor 1F, which has a power branching transmission mechanism substantially similar to that of the outboard motor 1A, as a starboard outboard motor 1F by positioning it on the starboard side of the transom board, the rotational centerline of the crankshaft 17 constituting the engine 5 is oriented substantially perpendicular to the water surface, and the rotational centerline of the crankshaft 17 and the rotational centerline of the drive shaft 100, which is linearly connected to the crankshaft 17 by spline fitting or the like, are arranged on a line parallel to the steering pivot shaft centerline of the outboard motor 1F (the centerline around which the outboard motor rotates left and right around the steering pivot shaft).

[0163] Therefore, the engine 5, which is the power source, is positioned on the engine holder 16 such that the rotational centerline of the crankshaft 17 constituting the engine 5 is oriented approximately perpendicular to the water surface. The drive shaft 100, which has its rotational centerline on the extension of the rotational centerline of the crankshaft oriented approximately perpendicular to the water surface and is linearly connected to the crankshaft 17 by spline fitting or the like, is positioned extending downward on the starboard side of the transom board.

[0164] Furthermore, in the driven shaft 101 that constitutes the outboard motor 1F, a fifth bevel angular contact 96, which is constantly engaged and connected to a fourth bevel angular contact 95 that rotates coaxially with the drive shaft 100, is fixed to the upper end of the driven shaft 101 and is positioned to extend diagonally downward outwards on the starboard side of the transom board.

[0165] The power branching transmission mechanism 94 is formed by the fourth bevel angular contact 95 and the fifth bevel angular contact 96. In addition, a power transmission path substantially the same as that of the outboard motor 1A is employed, apart from those described above.

[0166] In the aforementioned outboard motor 1F, it is mounted and fixed to the starboard side of the transom board of the hull, which has a V-shaped bottom. However, as with conventional outboard motors, various types of outboard motors 1F with different transom heights on the drive shaft 100 will be prepared.

[0167] When various outboard motors 1F with different transom heights are available, the gear case 102a on one side, through which the drive shaft 100 extends downward, is divided vertically into two parts along the line L-L perpendicular to the drive shaft 100, and is composed of an upper gear case 102aa and a lower gear case 102ab.

[0168] Then, an extension housing (not shown) is interposed between the lower surface of the upper gear case 102aa and the upper surface of the lower gear case 102ab at the joint L-L to adjust the transom height. Furthermore, after adjustment, the upper gear case 102aa and the lower gear case 102ab are integrated using bolts or the like with the extension housing interposed between them.

[0169] Furthermore, in the other gear case 102b of the outboard motor 1F, the gear case is divided vertically into two parts with M-M perpendicular to the rotational axis of the driven shaft 101 as the boundary, and is composed of an upper other gear case 102ba and a lower other gear case 102bb.

[0170] Furthermore, an extension housing (not shown) is interposed between the joint M-M between the lower surface of the upper other gear case 102ba and the upper surface of the lower other gear case 102bb to adjust the transom height. After adjustment, the upper other gear case 102ba and the lower other gear case 102bb are integrated using bolts or the like with the extension housing interposed between them.

[0171] The extension housing has an internal space, through which the drive shaft 100, the driven shaft 101, and the cooling water passages pass. Furthermore, the planar shape of the extension housing may be formed to be the same as the planar shape of the joint L-L or the joint M-M. Moreover, if the joints L-L and M-M are also formed to be the same shape, it can be used as a common part for one side gear case 102a and the other side gear case 102b.

[0172] In Japan, transom height is often indicated in millimeters, but this is a value converted from inches to millimeters. When converted back to inches, the transom height changes to 1x, 3x, 5x, etc., of 0.5 inches. Therefore, it is best to combine extension housings with thicknesses of 0.5 inches and 1 inch (or 0.5 inches only). Furthermore, extension housings with thicknesses of 0.5 inches, 1.5 inches, and 2.5 inches may be manufactured by integrally molding the extension housing itself with thicknesses of 1x, 3x, and 5x of 0.5 inches. In addition, to make fine adjustments, an extension housing with a thickness of 0.25 inches may be manufactured and combined.

[0173] Furthermore, when the extension housing is interposed, the drive shaft 100, driven shaft 101, and cooling water channel length will differ depending on the transom height, so various drive shafts of different lengths will be prepared.

[0174] (Other variations of the third embodiment) Next, other modifications of the third embodiment will be described. In the outboard motor 1F, it is installed on the starboard side of the transom board and used as a starboard outboard motor 1F. However, in the case of an outboard motor 1Y (not shown) installed on the port side of the transom board and used as a port outboard motor, the engine consists of a crankshaft that is oriented approximately perpendicular to the water surface and a drive shaft that is linearly connected to it by spline fitting or the like, with the drive shaft extending downward to the port side. In the driven shaft that constitutes the outboard motor 1Y, a fifth bevel angle, which is constantly meshed and connected to a fourth bevel angle that rotates coaxially with the drive shaft, is fixed to the upper end of the driven shaft and extends inclined downward and outward to the port side. The fourth bevel angle and the fifth bevel angle constitute a power branching transmission mechanism.

[0175] In the case of the outboard motor 1Y, it is mounted on the port side of the transom board of a hull having a V-shaped bottom surface. Similar to the outboard motor 1F described above, various types of outboard motors y with different transom heights on the drive shaft will be prepared.

[0176] Furthermore, if various outboard motors 1Y with different transom heights depending on the drive shaft are to be prepared, similar to the case of outboard motor 1F, the other side gear case is divided into two parts in a direction perpendicular to the rotational axis of the driven shaft, and is composed of an upper other side gear case and a lower other side gear case. An extension housing is interposed between the lower surface of the upper other side gear case and the upper surface of the lower other side gear case, and with the extension housing interposed, the upper other side gear case and the lower other side gear case are integrated using bolts or the like.

[0177] Furthermore, the gear case on one side of the outboard motor 1Y is divided into upper and lower halves in a direction perpendicular to the rotational axis of the driven shaft, and is composed of an upper gear case and a lower gear case. An extension housing is interposed between the lower surface of the upper gear case and the upper surface of the lower gear case, and the upper gear case and the lower gear case are integrated together with bolts or the like with the extension housing interposed.

[0178] In the case of the outboard motor 1F, which is positioned and fixed on the starboard side of the transom board of a hull having a V-shaped bottom and used for the starboard side, and the outboard motor Y, which is positioned and fixed on the port side of the transom board and used for the port side, the components that make up the outboard motor 1A described above can be used as common components, thereby reducing costs.

[0179] In the starboard outboard motor 1F, both the propeller 30 rotated by the drive shaft 100 and the propeller 31 rotated by the driven shaft 101 are rotated to the right for forward movement and to the left for reverse movement. Furthermore, in the port outboard motor 1Y, both the propeller 31 rotated by the drive shaft and the propeller 30 rotated by the driven shaft are rotated to the left for forward movement and to the right for reverse movement. Thus, the lateral pressure (counter torque) at the keel of the hull is canceled out, improving the straight-line stability of the hull and preventing the hull from tilting due to reaction forces. Furthermore, by reversing (or moving forward) the starboard outboard motor 1F and moving forward (or moving backward) the port outboard motor 1Y, the bow can be turned to the right (or left) within a narrow range, making it easier to dock and undock the hull.

[0180] However, if one outboard motor becomes inoperable, the remaining outboard motor will be unable to counteract the lateral pressure (counter torque) between its propeller and the other propeller when traveling in a straight line, resulting in reduced straight-line stability.

[0181] Furthermore, when the starboard outboard motor 1F mounted on the starboard side of the transom board and the port outboard motor 1Y mounted on the port side of the transom board are rotated in opposite directions to move forward (or backward), the lateral pressure (counter torque) between the two propellers of each outboard motor 1F and 1Y cancels out, and the straight-line stability of the hull can be improved by the starboard outboard motor 1F and the port outboard motor 1Y. In this combination, even if one outboard motor becomes inoperable, the remaining outboard motor can maintain a certain degree of straight-line stability, allowing the vessel to continue sailing.

[0182] The above description concerns embodiments of the present invention and does not limit the apparatus and methods of this invention, and various modifications can be easily implemented. Furthermore, apparatuses or methods configured by appropriately combining the components, functions, features, or method steps of each embodiment are also included in the present invention. [Industrial applicability]

[0183] By applying the present invention, the outboard motor only requires one power source, and because it has two shafts—a port side propeller shaft and a starboard side propeller shaft—it is possible to secure a large propeller area and increase the output of the outboard motor. Furthermore, although it has two shafts—a port side propeller shaft and a starboard side propeller shaft—it only requires one power source, which simplifies and compacts the prime mover, and thus reduces the overall weight of the hull. The present invention can be used in the field of outboard motors. [Explanation of Symbols]

[0184] 1, 1J, 1JL, 1JR, 1A, 1AA, 1F, 1Y… Outboard motor, 1E, 1JE… Electric outboard motor, 2… Cowl, 3, 73, 90… Carrier body, 4… Lower unit, 5… Power source (engine), 6, 71… Drive shaft, 71a… Upper drive shaft, 71b… Lower drive shaft, … Drive shaft, 7… Port side driven shaft, 7J… One side driven shaft, 8… Starboard side driven shaft, 8J… Other side driven shaft, 9… Power bidirectional transmission mechanism, 10… Port side propeller shaft, 10J… One side propeller shaft, 11… Starboard side propeller shaft, 11J… Other side propeller shaft, 12… Port side gear mechanism, 13… Starboard side gear mechanism, 14… Shift Mechanism, 15, 15a…Upper power unit, 16…Engine holder, 17…Crankshaft, 18, 18a, 18b…Water pump, 19…First bevel angular contact, 20…Second bevel angular contact, 21…Third bevel angular contact, 22…Port side pinion gear, 23…Starboard side pinion gear, 24, 27…Forward gear, 25, 28…Reverse gear, 26…Port side dog clutch, 29…Starboard side dog clutch, 30…Port side propeller, 30J…One side propeller, 31…Starboard side propeller, 31J…Other side propeller, 32…Port side shift cam, 33…Starboard side shift Cam, 34, 91, 102…Gear case, 34a…Port side gear case, 34b…Starboard side gear case, 35…Upper gearbox, 36…Port side gearbox, 37…Starboard side gearbox, 38a…Port side shift plunger, 38b…Starboard side shift plunger, 40a…Port side gear shift handle, 40b…Starboard side gear shift handle, 41a…Support shaft for port side gear shift handle 40a, 41b…Support shaft for starboard side gear shift handle 40b, 42a…Port side lever shift rod, 42b…Starboard side lever shift rod, 43a…Port side flexible Outer case, 43b... Starboard flexible outer case, 44a... Port side push-pull flexible inner cable, 44b... Starboard push-pull flexible inner cable, 51... Cooling water intake, 52a... Port side cooling water channel, 52b... Starboard side cooling water channel, 53... Upper cooling water channel, 54a... Port side bypass water channel, 54b... Starboard side bypass water channel, 55... Rotation stop mechanism, 56... Helm pump, 57... Passive steering cylinder, 58a, 58b... Each hydraulic fluid inlet / outlet valve of the passive steering cylinder 57 body, 59a, 59b... Each hydraulic fluid inlet / outlet valve,60a...Wide type anti-cavitation plate, 60b...Narrow type anti-cavitation plate, 60as...Back surface of wide type anti-cavitation plate 60a, 60bs...Back surface of narrow type anti-cavitation plate 60b, 61a...Left side mounting part, 61b...Right side mounting part, 63, 76, 87...Male thread, 64, 75...Female thread, 65, 74...Male screw through hole, 70...Constant velocity joint, 72...Flexible boot, 73a...Upper carrier body, 73b...Lower carrier body, 77...Internal space, 78...Exterior cover, 79a...One side damper mount, 79b...Other side damper mount, 80a...One side mounting part, 80b...Other side mounting part, 81a...One side arm base, 81b...Other side arm base, 82a...One side damper mount mounting arm, 82b...Other side damper mount mounting arm, 83... Lower support part of steering pivot shaft, 84... Support base plate with support part 83, 85a, 85b... One side torque rod mounting part, 85c, 85d... Other side torque rod mounting part, 86, 86a, 86b... Spectacle-shaped torque rod, 91a... Port side gear case, 91b... Starboard side gear case, 92, 100... Drive shaft, 93, 101... Driven shaft, 94... Power branching transmission mechanism, 95... Fourth bevel angular, 96 …Fifth bevel angular, 102a…one side gear case, 102aa…upper one side gear case, 102ab…lower one side gear case, 102b…other side gear case, 102ba…upper other side gear case, 102bb…lower other side gear case, 200…hull, 600…anti-cavitation plate, 600L…port side anti-cavitation plate, 600R…starboard side anti-cavitation plate.

Claims

1. Power source (5), The drive shaft (6) rotates coaxially and is driven by the power source (5) and extends downward, A first bevel angular (19) rotates coaxially with the drive shaft (6) and has its smaller diameter side facing upward, A second bevel angular contact (20) is constantly engaged with the first bevel angular contact (19) in an inclined manner with its smaller diameter side facing upward, A port-side driven shaft (7) rotates coaxially with the second bevel angular (20) and extends in a downward oblique direction on the port side, A third bevel angle (21) is constantly engaged with the first bevel angle (19) in an inclined manner and rotates in the same direction as the second bevel angle (20), The starboard driven shaft (8) rotates coaxially with the third bevel angular (21) and extends in a downward oblique direction on the starboard side, A port-side propeller shaft (10) is connected to the port-side driven shaft (7) and extends in a direction intersecting the axis of the port-side driven shaft (7), A port-side propeller (30) rotates by the aforementioned port-side propeller shaft (10), A starboard propeller shaft (11) is connected to the starboard driven shaft (8) and extends in a direction intersecting the axis of the starboard driven shaft (8), The starboard propeller (31) rotates on the aforementioned starboard propeller shaft (11), An outboard motor with a single engine and two shafts, characterized in that it has a power transmission system comprising a power two-way transmission mechanism (9) composed of the first bevel angular (19), the second bevel angular (20), and the third bevel angular (21), thereby providing a straight thrust to the hull (200).

2. Power source (5), The drive shafts (92, 100) rotate coaxially and are driven by the power source (5) and extend downward, A fourth bevel angular (95) rotates coaxially with respect to the aforementioned drive shafts (92, 100) and has its smaller diameter side facing upward, A fifth bevel angular contact (96) is constantly engaged with the fourth bevel angular contact (95) in an inclined manner with its smaller diameter side facing upward, The driven shafts (93, 101) rotate coaxially with the fifth bevel angular (96) and extend downward, A propeller shaft (10) is connected to the drive shafts (92, 100) and extends in a direction intersecting the axis of the drive shafts (92, 100), The port side propeller (30) rotates on the propeller shaft (10), A propeller shaft (11) is connected to the driven shafts (93, 101) and extends in a direction intersecting the axis of the driven shafts (93, 101), The starboard propeller (31) rotates on the propeller shaft (11), The drive shafts (92, 100) extend downward on the port side or downward on the starboard side, and the driven shafts (93, 101) extend downward on the starboard side or downward on the port side. An outboard motor with a single engine and two shafts, characterized in that it has a power branching transmission mechanism (94) composed of the fourth bevel angular (95) and the fifth bevel angular (96) to constitute a power transmission system, thereby providing a straight thrust to the hull (200).

Images