Improvements in or related to marine propulsion systems

Abstract

This invention provides an external propulsion system that suppresses the reduction in thrust during turns. [Solution] An outboard propulsion system comprising: a first part having an engine including a crankshaft; and a second part having a propeller shaft having a longitudinal axis along its length, wherein the propeller shaft is operably connected to the crankshaft via a drive shaft configured to transmit power to the crankshaft, the drive shaft having a drop shaft which is substantially perpendicular to the propeller shaft, the second part being configured to pivot with respect to the first part about a steering axis which intersects the longitudinal axis of the propeller shaft at an obtuse angle, the first and second parts being configured to tilt together about a single axis of rotation substantially parallel to the stern of the boat, and the first part being fixed about a substantially vertical axis.

Description

Technical Field

[0001] The present invention relates to improvements in or related to marine propulsion systems, and more particularly to outboard propulsion systems.

Background Art

[0002] Conventional outboard propulsion systems are self - contained units that can be mounted on the transom of a boat. The system includes an engine, a transmission, and a propeller (or jet drive). To control the direction of the thrust from the propeller and thus steer the boat, the entire unit can rotate about a vertical steering axis relative to the transom. Also, to trim the angle of attack of the thrust and / or to tilt the unit upward, for example when not in use, the entire unit can be rotated about a horizontal trim / tilt axis of a transverse axis relative to the transom.

[0003] Conventional configurations of outboard motors include a powerhead with an engine. The powerhead typically has a vertical crankshaft, although horizontal crankshafts have also been used. A drive shaft extends vertically from the powerhead, typically into a central section that houses an oil sump and raw water and exhaust passages. The central section may also house parts of the gearbox. A lower unit houses gears configured to transmit power from the vertical drive shaft to a horizontal propeller shaft. The powerhead, central section, and lower unit are attached to form a single unit that rotates about the steering axis and trim / tilt axis as described above.

[0004] These propulsion systems consist of one or more complex attachments to the boat's transom, including hydraulic systems that allow the entire propulsion system to rotate around its steering axis and trim / tilt axis. This complexity stems partly from the number of axes of rotation and partly from the need for the entire system to rotate around these axes. Rotating the powerhead requires considerable force, and sufficient space is needed around the boat's transom for the powerhead to rotate around the steering axis. To accommodate these rotational movements, the powerhead is usually supported quite far aft of the transom. As a result, many conventional outboard motors have a steering lever that extends into the boat's hull. This lever is mounted to the powerhead and is used to rotate the outboard motor relative to the transom in order to steer the board. The lever requires sufficient space to rotate and occupies valuable space within the boat's hull.

[0005] Furthermore, conventional outboard propulsion systems limit the speed at which a boat can make sharp turns. As the boat leans into a corner, the change in the transom angle can cause the outboard propeller to lift out of the water, potentially significantly reducing the boat's speed. This problem is exacerbated by the substantially horizontal and planar movement of conventional propeller shafts during turns. To mitigate this effect, the outboard propulsion system, including the propeller shaft, needs to be trimmed before the start of a turn so that the propeller does not protrude above the waterline. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention arose from the above background. [Means for solving the problem]

[0007] According to the present invention, a first part for attachment to a boat having a stern, An outboard propulsion system is provided, comprising: a first part having an engine including a crankshaft; and a second part having at least one propeller shaft having a longitudinal axis along its length, wherein the at least one propeller shaft is operably connected to a crankshaft, the second part is configured to pivot relative to the first part about a steering axis, the steering axis intersects the longitudinal axis of the at least one propeller shaft at an obtuse angle, the first and second parts are configured to tilt together about a single axis of rotation substantially parallel to the stern of the boat, and the first part is fixed about a substantially vertical axis.

[0008] A propulsion system with a first part fixed approximately around a vertical axis prevents the first part and / or the engine from rotating or pivoting around the stern of the boat. This significantly reduces the amount of space that would have been required around the first part to allow such motion. Furthermore, the entire outboard propulsion system can be positioned closer to the stern of the boat, and more robust and / or simpler mounting means can be used to attach the first part to the boat. This is because the first part has less freedom of movement compared to conventional outboard motors, and therefore the complexity of the coupling is also reduced. Each of these factors may allow the use of a larger and / or more powerful engine for a given overall system size, also known as the “packaging” size. Alternatively or additionally, each of these factors may allow for a smaller packaging size for a given engine. Note that in this context, the term packaging size includes the size of the entire propulsion system, in addition to the space required for the entire propulsion system to move or rotate.

[0009] Furthermore, enabling the first and second parts to tilt integrally around a single axis of rotation that is substantially parallel to the stern of the boat allows the entire second part to be lifted out of the water, which may be necessary, for example, during system maintenance. In some embodiments, the stern of the boat may be curved, and / or the first and second parts may tilt integrally around a single curved axis of rotation. Alternatively or additionally, the first and second parts may be configured to tilt integrally around a single axis substantially perpendicular to the longitudinal axis of the boat. In some embodiments, the first and second parts may have a single degree of freedom when tilted integrally.

[0010] Furthermore, allowing the first and second sections to be tilted integrally around a single axis of rotation substantially parallel to the stern of the boat may enable at least one propeller shaft to be trimmed up and / or trimmed down. This allows the user to raise and lower the bow of the boat, resulting in improved boat performance (speed and handling) and fuel savings (due to reduced drag).

[0011] The obtuse angle between the steering axis and the longitudinal axis of at least one propeller shaft allows the engine to be positioned at an acute angle with respect to the longitudinal axis of the boat. It also allows the engine to be positioned at an acute angle with respect to the nearly vertical axis. The aforementioned arrangements allow the use of conventional horizontal engines, and thus allow the use of reliable, highly efficient, and robust engine designs. In some embodiments, conventional horizontal engines may require modifications to optimize the system.

[0012] The obtuse angle between the longitudinal axis and the steering axis of at least one propeller shaft can result in a thrust vector with an upward component generated by the outboard propulsion system. For example, at least one propeller shaft may have a proximal end and a distal end, where the proximal end is closer to the engine than the distal end. At least one propeller shaft may further include at least one propeller, where the distal end is closer than the proximal end. When the second part is rotated relative to the first part, the obtuse angle between the steering axis and the propeller axis is This causes the distal end of the propeller shaft to be lowered relative to the proximal end, thus giving an upward component to the thrust vector generated by at least one propeller during use. This motion reduces the likelihood of at least one propeller bouncing out of the water during turns. Furthermore, this motion lowers the bow of the boat, reducing the likelihood of the boat skidding sideways on the water surface during turns.

[0013] Furthermore, fixing the first part to the boat and allowing relative movement of the second part provides significant advantages when maneuvering a twin outboard motor boat sideways, for example during docking and / or undocking, as well as any other out-of-plane maneuvers. As is commonly known in the boating industry, the propellers of each outboard propulsion system in a twin outboard motor boat rotate in opposition to each other as part of this common maneuver. Therefore, fixing the first part significantly reduces the possibility of the systems coming into contact or colliding with each other during maneuvering.

[0014] Securing the first part to the boat further reduces the number of moving components near the boat and / or eliminates moving components in some embodiments. The absence of moving parts around the boat's transom is safer for passengers and crew.

[0015] In some embodiments, the outboard propulsion system may be electric. The outboard propulsion system comprises a first part for mounting to a boat having a stern, the first part having at least one electric motor; and a second part having at least one propeller shaft having a longitudinal axis along its length; the at least one propeller shaft being operably connected to the electric motor, the second part being configured to pivot relative to the first part about a steering axis, the steering axis intersecting the longitudinal axis of the at least one propeller shaft at an obtuse angle, the first and second parts being configured to tilt together about a single axis of rotation substantially parallel to the stern of the boat, and the first part being fixed about a substantially vertical axis.

[0016] Providing a fully electric outboard propulsion system eliminates carbon emissions from the system during use and significantly reduces the system's environmental impact. Electric motors also reduce the amount of noise generated by the system during use, potentially allowing the outboard propulsion system to be used in locations where non-electric systems are not permitted.

[0017] Furthermore, an outboard propulsion system equipped with an electric motor can provide more torque than an outboard propulsion system equipped with an internal combustion engine. Electric systems can also deliver a predetermined amount of torque more quickly than systems equipped with an internal combustion engine. This improved torque output can be more effectively utilized by the outboard propulsion system as a result of the upward component of the thrust vector. In addition, the improved torque output can be used more efficiently to generate thrust within an outboard propulsion system with multiple propeller shafts. Therefore, electric motors can result in improved dynamics compared to outboard propulsion systems equipped with an internal combustion engine.

[0018] In embodiments where the outboard propulsion system is electric, the system would further include at least one battery. The provision of a battery allows the system to obtain its power from a more efficient source, such as the national power grid. The energy is then stored in the battery and can be used later, for example, when the boat and the outboard motor system attached to the boat are located in a body of water such as a lake or ocean.

[0019] The outboard propulsion system further comprises a fixing mechanism configured to attach the first part to the stern of the boat, the fixing mechanism may be configured to allow only a single axis of rotation substantially parallel to the stern of the boat.

[0020] Alternatively or additionally, the fixing mechanism may have a single degree of freedom.

[0021] A stationary mechanism that allows only a single axis of rotation and / or a single degree of freedom makes the connection between the first part and the boat stronger and more robust. It also allows for the incorporation of additional supports and more durable connections into the stationary mechanism to support the first part, which would otherwise be impossible. As a result, heavier, larger, and / or more powerful engines can be used.

[0022] The mounting mechanism may include a cradle and a transom bracket.

[0023] The transom bracket may be configured to secure to the stern of the boat and prevent relative movement between them. Doing so provides a solid and robust unit for connecting to the cradle.

[0024] The cradle may be fixed to the first part and configured to prevent relative movement between them. Fixing the cradle to the first part and preventing relative movement between them allows for the creation of a robust connection between the first part and the cradle.

[0025] The fixing mechanism further comprises at least one pad disposed between the cradle and the first part, and the at least one pad may be configured to reduce the transfer of vibration energy between the first part and the cradle.

[0026] Reducing the transfer of vibration energy between the first part and the cradle reduces the distortion applied to the transom bracket and its connections. It further provides a smoother and quieter ride for the boat's passengers. The at least one pad may be at least one rubber pad. The fixing mechanism may comprise 1, 2, 3, 4, 5, 8, 10, or more than 10 pads.

[0027] The cradle is connected to the transom bracket, and the connection between the cradle and the transom bracket may be configured to allow only a single axis of rotation substantially parallel to the stern of the boat.

[0028] Allowing only a single axis of rotation substantially parallel to the stern of the boat between the cradle and the transom bracket prevents the first part from rotating and / or pivoting about a substantially vertical axis. This prevents the need for additional space around the stern of the boat and allows the center of mass of the engine to be positioned closer to or even within the hull of the boat.

[0029] The engine may comprise a crankcase. The crankshaft may be disposed within the crankcase. The outboard propulsion system may further comprise at least one drive shaft operably connected between the crankshaft and at least one propeller shaft and configured to transmit power therebetween. In some embodiments, the outboard propulsion system may comprise a single drive shaft. In some embodiments, the outboard propulsion system may comprise a plurality of drive shafts. The outboard propulsion system preferably comprises between 2 and 5 (including 2 and 5) drive shafts.

[0030] Providing at least one drive shaft positioned between the crankshaft and at least one propeller shaft makes it possible to optimize the system's center of mass. In addition, the positional position of certain components relative to each other, relative to the boat, and / or the water surface can also be optimized. Providing at least one drive shaft positioned between the propeller shafts could, for example, allow for the integration of a transmission / gear assembly into the system.

[0031] In some embodiments, at least one drive shaft may be operably connected to at least one propeller shaft via a first bevel gear. In some embodiments, a single drive shaft may be operably connected to at least one propeller shaft via a first bevel gear. On the other hand, in some embodiments, multiple drive shafts may be operably connected to at least one propeller shaft via a first bevel gear.

[0032] Using a first bevel gear to connect at least one drive shaft to at least one propeller shaft minimizes the number of components and results in a lighter system.

[0033] At least one drive shaft may be a drop shaft (registered trademark), and the drop shaft may be approximately perpendicular to at least one propeller shaft. In some embodiments, there may be multiple drive shafts, one of which may be a drop shaft. In some embodiments, there may be multiple drive shafts, at least one of which may be an intermediate shaft. In some embodiments, there may be one drop shaft and one intermediate shaft. In some embodiments, there may be one drop shaft and multiple intermediate shafts. In some embodiments, at least one drive shaft may be a first intermediate shaft.

[0034] In some embodiments, at least one drive shaft may comprise a first intermediate shaft and a second intermediate shaft. In some embodiments, at least one drive shaft may comprise a first intermediate shaft, a second intermediate shaft, and a drop shaft.

[0035] The drop shaft may be operably connected between the first intermediate shaft and at least one propeller shaft. Alternatively, the drop shaft may be operably connected between the second intermediate shaft and at least one propeller shaft.

[0036] Providing a drop shaft that is nearly perpendicular to at least one propeller shaft allows the second part to accommodate a conventional lower unit. Therefore, a reliable, efficient, and relatively inexpensive conventional lower unit can be used. This results in a more robust system, as well as reduced manufacturing costs and time. Furthermore, providing a drop shaft that is nearly perpendicular to at least one propeller shaft brings at least one propeller shaft closer to the fixing mechanism, and consequently closer to the boat during use. This brings the system's center of mass closer to the boat, reducing the strain on the fixing mechanism and improving the boat's handling during use.

[0037] A first intermediate shaft may be movably connected between the crankshaft and the drop shaft, and the first intermediate shaft may be movably connected to the drop shaft via a first bevel gear. Alternatively, a second intermediate shaft may be movably connected between the first intermediate shaft and the drop shaft, and the second intermediate shaft may be movably connected to the drop shaft via a first bevel gear.

[0038] The first intermediate shaft or the second intermediate shaft is connected to the first bevel gear via the drop shaft Connecting to a bevel gear provides a lighter and more efficient coupling than other types of couplings, such as constant velocity (CV) couplings. Furthermore, bevel gears result in a quieter overall system than comparable CV couplings.

[0039] On the other hand, in some embodiments, the bevel gear may be replaced with a universal joint and / or a constant velocity joint. Thus, the first or second intermediate shaft may be operably connected between the crankshaft and the drop shaft via a constant velocity joint or a universal joint.

[0040] The first intermediate shaft and / or the second intermediate shaft may be substantially parallel to the longitudinal axis of the crankshaft.

[0041] Providing a first or second intermediate shaft that is substantially parallel to the longitudinal axis of the crankshaft limits the number of bevel gears (or equivalents) required, and therefore provides a more efficient system.

[0042] At least one propeller shaft comprises an inner propeller shaft and an outer propeller shaft, the outer propeller shaft being hollow and configured to receive at least a portion of the inner propeller shaft.

[0043] Providing an inner and outer propeller shaft allows propellers to be connected to the inner and outer shafts, respectively. In this case, at least two propellers may be configured to independently receive power from at least one drop shaft and provide thrust. The inner and outer propeller shafts may be concentric.

[0044] The inner propeller shaft may be operably connected to at least a first propeller, and the outer propeller shaft may be connected to at least a second propeller. The first propeller may be located at the distal end of the inner propeller shaft. The second propeller may be located between the first propeller and the proximal ends of the inner and outer propeller shafts.

[0045] Providing an inner propeller shaft with a first propeller and a second propeller shaft with a second propeller can increase the efficiency of torque transfer between the drop shaft and each propeller. The resulting system will be more efficient.

[0046] The steering shaft may extend approximately parallel to the longitudinal axis of the crankshaft.

[0047] By positioning the steering axis approximately parallel to the longitudinal axis of the crankshaft, fewer bevel gears are required within the system. This reduces the number of components, resulting in a smaller overall system and thus a smaller package size that is less expensive to manufacture. Furthermore, a smaller system allows the center of mass to be positioned closer to the boat's transom, improving maneuverability.

[0048] Alternatively, the steering shaft may intersect the longitudinal axis of the crankshaft at an acute angle. This configuration may include additional bevel gears that can be used to optimize the system's center of mass. For example, the system's center of mass may be moved toward the boat's transom. The steering shaft may intersect the longitudinal axis at an angle between 0 and 10 degrees, 10 and 20 degrees, 20 and 30 degrees, 30 and 40 degrees, 40 and 50 degrees, 50 and 60 degrees, 60 and 70 degrees, 70 and 80 degrees, or 80 and 90 degrees (including the angles listed).

[0049] The drop shaft may be connected to at least one propeller shaft via at least a second bevel gear. The second bevel gear may be a 90-degree bevel gear.

[0050] In some embodiments, there may be multiple drop shafts. For example, there may be two drop shafts. The two drop shafts may be concentric. Alternatively, the two drop shafts may be parallel. Multiple drop shafts can more efficiently transmit power between the crankshaft and at least one propeller shaft.

[0051] At least a second bevel gear may be operably connected to at least one clutch. A first clutch may be operably connected between a second bevel gear and a first drop shaft, and the first clutch may be configured to rotate the drop shaft in a first direction. A second clutch may be operably connected between a third bevel gear and a second drop shaft, and the second clutch may be configured to rotate the second drop shaft in a second direction.

[0052] The outboard propulsion system may further comprise a transmission assembly configured to control the power supplied to at least one propeller shaft.

[0053] Providing a transmission assembly enables the power supplied to at least one propeller shaft to be controlled, regulated, and / or adjusted. The speed and direction of at least one propeller shaft can be controlled, and consequently, the boat's speed and direction of travel can be controlled. The transmission assembly may include a reversing gear configured to reverse the rotation direction of at least one propeller shaft. Furthermore, in addition to increasing or decreasing the output power, the transmission assembly may be configured to turn the outboard propulsion system on and / or off.

[0054] The transmission assembly may be located in the first part.

[0055] Placing the transmission assembly in the first position ensures that the system's center of mass remains as close as possible to the cradle, and consequently, to the boat's transom. This reduces stress on the fixing mechanism, potentially improving the boat's control and handling during use.

[0056] The drive shaft may include a transmission input drive shaft. Alternatively or additionally, the drive shaft may include a transmission output drive shaft. The first intermediate shaft may be a transmission input drive shaft. Alternatively or additionally, the second intermediate shaft may be a transmission output drive shaft. Conversely, the second intermediate shaft may be operably connected to the transmission output drive shaft. The first intermediate shaft may be substantially parallel to the second intermediate shaft. Alternatively or additionally, the second intermediate shaft may be laterally spaced from the second intermediate shaft. The transmission assembly may further include a pair of offset gears configured to bring the second portion closer to the fixing mechanism. The offset pair of gears may include a first gear mounted on the transmission output shaft and a second gear mounted on the second intermediate shaft. The first gear may be configured to engage with the second gear. As a result, the first gear can transmit power to the second gear when in use.

[0057] Bringing the second section closer to the stationary mechanism brings the center of mass of the entire outboard propulsion system closer to the stern of the boat. Doing so reduces the load and, consequently, the moment of force acting on the stationary mechanism. Reducing the moment of force acting on the stationary mechanism reduces the impact load on the stern of the boat caused by the movement of the outboard propulsion system during use.

[0058] The steering axis may intersect the longitudinal axis of at least one propeller shaft at an angle between 100 and 140 degrees. Alternatively or additionally, the steering axis may intersect the longitudinal axis of at least one propeller shaft at an angle of approximately 120 degrees.

[0059] In some embodiments, the steering shaft may intersect the propeller shaft at an angle between 90 and 180 degrees, 95 and 160 degrees, 100 and 140 degrees, 110 and 130 degrees, 115 and 125 degrees, or approximately 120 degrees.

[0060] Alternatively or additionally, an outboard propulsion system is also provided comprising: an engine configured to receive oil; an oil pan configured to receive oil from the engine; and an oil reservoir configured to receive oil from the oil pan and to supply oil to the engine when in use.

[0061] More specifically, an outboard propulsion system is also provided, comprising: an engine having a crankshaft positioned within a crankcase configured to receive oil; an oil pan configured to receive oil from the crankcase; and an oil reservoir configured to receive oil from the oil pan and supply oil to the engine when in use.

[0062] An outboard propulsion system with an oil reservoir and oil pan results in a dry oil sump system. This improves the system's efficiency because it increases the likelihood that the oil pickup in the reservoir will remain below the oil level during use. As a result, the outboard propulsion system can continue to deliver oil to the engine, for example, during sharp turns. This will increase the power generated by the engine during turns. Moreover, the necessary oil pressure is thus maintained, protecting the engine from potential damage. In addition, a separate oil reservoir reduces the amount of oil in the engine and oil pan at any given time. This can be used to prevent the crankshaft from coming into contact with the oil in the oil pan during use. This reduces unnecessary drag on the crankshaft and thus further improves the system's efficiency.

[0063] Furthermore, a separate oil reservoir can be positioned in a more favorable location within the outboard propulsion system, thus optimizing the weight distribution of the outboard propulsion system. A larger oil reservoir can also be used compared to an equivalent wet oil sump system. For example, the crankcase, oil pan, and oil reservoir may hold between 5 and 12 liters of oil. Alternatively, the engine, oil pan, and oil reservoir may hold between 5 and 12 liters of oil. Approximately 4 to 11 liters may be in the oil reservoir. Approximately 1 to 4 liters may be in the crankcase and / or oil pan. Alternatively, approximately 1 to 4 liters may be in the engine and / or oil pan.

[0064] The oil reservoir may be located adjacent to the engine. For example, the oil reservoir may be located directly adjacent to the engine. Alternatively or additionally, the oil reservoir may be located above the engine when in use. In some embodiments, the oil reservoir may be located behind the engine. Alternatively, the oil reservoir may be located in front of the engine. For example, in a boat with a transom, the oil The reservoir may be positioned forward of the engine so that, when in use, the oil reservoir is located between the engine and the boat's transom. Alternatively, the oil reservoir may be positioned aft of the engine with respect to the boat when in use. Thus, the location of the oil reservoir can be optimized to allow the engine to be positioned closer to the stern of the boat and / or closer to the water level when in use. This results in a more favorable weight distribution within the outboard propulsion system. The location of the oil reservoir can also be optimized to allow easy access to the reservoir from inside the boat to which the outboard propulsion system is mounted.

[0065] The oil reservoir may be removable. For example, the oil reservoir may be removable from the outboard propulsion system. Alternatively or additionally, the oil reservoir may be detachable. For example, the oil reservoir may be completely detachable from the outboard propulsion system. This would allow the first oil reservoir and the oil inside it to be replaced with a second oil reservoir containing fresh oil. This would eliminate the need for the user to unplug the oil reservoir and drain the oil. As a result, the ease of maintaining the system is improved.

[0066] The outboard propulsion system may further comprise a transmission assembly having an oil transfer pump. The oil transfer pump may be configured to pump oil from the oil pan to the oil reservoir. Placing the oil transfer pump in the transmission assembly improves the overall packaging of the system. Furthermore, the oil transfer pump may utilize an existing shaft in the transmission to receive power. This eliminates the need for a separate drive system such as belts, chains, or gears, thus reducing the number of components and the likelihood of failure in the outboard propulsion system. Finally, placing the oil transfer pump in the transmission lowers the overall center of mass of the system compared to conventional outboard propulsion systems. This improves handling and / or conveniently allows the oil transfer pump to be positioned below the engine and / or crankcase, so that gravity assists the drainage of oil from the engine and through the crankcase. This increases the efficiency of the pump.

[0067] Alternatively or additionally, the outboard propulsion system may include an electric motor configured to provide power to an oil transfer pump. The electric motor may be the primary power source for the oil transfer pump. Alternatively, the electric motor may be a backup power source for the oil transfer pump. For example, in some embodiments, an electric motor may be more desirable when the oil reservoir is detachable and / or removable.

[0068] Alternatively or additionally, the oil transfer pump may be configured to receive power directly from the transmission assembly. A pump that receives power directly from the transmission assembly should have less energy loss than a pump that is powered indirectly through the engine and / or transmission assembly. The power may be in the form of rotational energy.

[0069] The transmission assembly may be configured to receive power from the engine via at least one drive shaft. Alternatively or additionally, the transmission assembly may be configured to power an oil transfer pump via a pump shaft. The pump shaft may be located within the transmission assembly. Having the pump shaft within the transmission assembly allows for optimization of the location of the oil transfer pump. This can improve the weight distribution and / or handling of the outboard propulsion system.

[0070] The pump shaft may be directly connected to the forward gear. Alternatively or additionally, the pump shaft may be directly connected to the forward clutch. More specifically, the pump shaft may be directly connected to the forward clutch and / or the forward gear. This reduces the number of components required within the transmission, and therefore improves the overall packaging and weight of the system.

[0071] The transmission assembly may be configured to receive power from the crankshaft via at least one driveshaft. The driveshaft between the engine and the transmission may include a first intermediate shaft. Thus, the pump shaft can receive power from the crankshaft via the input driveshaft when in use.

[0072] The drive shaft may include an input drive shaft. The pump shaft may be operably connected to the crankshaft via the input drive shaft. The input drive shaft may be directly connected to the crankshaft. The input drive shaft may receive power directly from the crankshaft during use. The output drive shaft may receive power from the crankshaft via the input drive shaft during use. The input drive shaft may be a first intermediate shaft.

[0073] The transmission may include an output drive shaft. The output drive shaft may be a second intermediate shaft. Alternatively, the output drive shaft may be operably connected to the second intermediate shaft via a pair of offset gears.

[0074] The pump shaft may be configured to rotate at all times when the engine is turned on. Alternatively or additionally, the pump shaft may be configured to rotate at all times when in use. Having a separate pump shaft within the transmission assembly configured to rotate at all times when the engine is turned on ensures that the oil transfer pump is always operational, regardless of the power supplied to the propeller shaft. More specifically, the rotation of the pump shaft may be directly related to the rotation of the crankshaft. As a result, as the rotational speed of the crankshaft increases, the rotational speed of the pump shaft also increases. Therefore, as the rotational speed of the crankshaft decreases, the rotational speed of the pump shaft also decreases. This ensures that the appropriate flow rate of oil is delivered to the oil reservoir when in use.

[0075] The pump shaft may be laterally spaced from the input drive shaft. Alternatively or additionally, the pump shaft may be laterally spaced from the output drive shaft and / or a second intermediate shaft. Laterally spacing the pump shaft and input shaft can improve the overall system packaging. Laterally spacing the pump shaft and input shaft can also allow for optimization of the weight distribution of the outboard propulsion system. The pump shaft and input shaft may be approximately parallel.

[0076] In some embodiments, the pump shaft may be operably connected to the forward clutch shaft. More specifically, the pump shaft may be operably connected to the forward clutch shaft via a spinal hex coupling. Thus, the forward clutch shaft and the pump shaft may be at least partially concentric and / or coaxial.

[0077] The outboard propulsion system may further include a lip seal configured to provide a substantially liquid-tight seal between the transmission assembly and the engine. More specifically The lip seal may be configured to provide a substantially liquid-tight seal between the transmission assembly and the engine. Most specifically, the lip seal may be configured to provide a substantially liquid-tight seal between the transmission assembly and the crankcase. As a result, the lip seal prevents oil from the engine and / or crankcase from entering the transmission assembly. More specifically, the outboard propulsion system may include multiple lip seals configured to provide a substantially liquid-tight seal between the transmission assembly and the engine.

[0078] As previously disclosed, the outboard propulsion system may further comprise a first part for mounting to a boat. The first part may comprise an engine. The first part may further comprise a crankcase and a crankshaft. The first part may further comprise an oil pan, an oil reservoir, and / or a transmission assembly.

[0079] The outboard propulsion system may further include a drop shaft operably connected between the transmission assembly and the propeller shaft. The drop shaft may be approximately perpendicular to the propeller shaft. The outboard propulsion system may also include an output drive shaft operably connected between the transmission assembly and the drop shaft. The output drive shaft may be operably connected to the drop shaft via a first bevel gear.

[0080] The crankshaft may have a longitudinal axis along its length. The driveshaft may be substantially parallel to the longitudinal axis of the crankshaft. The steering shaft may extend substantially parallel to the longitudinal axis of the crankshaft. Alternatively or additionally, the outboard propulsion system may include a turbocharger. The turbocharger can increase the power generated by the engine and / or reduce the amount of waste generated.

[0081] The turbocharger may be positioned behind the engine during use. As a result, the turbocharger will be located behind the engine during use. For example, the engine may be positioned between the turbocharger and the boat during use. Alternatively or additionally, the engine may be positioned between the turbocharger and the oil reservoir.

[0082] A turbocharger may be configured to receive oil. More specifically, a turbocharger may be configured to receive oil from an oil reservoir. The oil may be pumped from the oil reservoir to the turbocharger by an oil supply pump. The oil may be supplied to the turbocharger to lubricate the bearings within the turbocharger. Furthermore, a turbocharger may have a drain configured to remove excess oil from within the turbocharger. The drain may be in fluid communication with the oil reservoir. More specifically, the drain may be in fluid communication with the oil reservoir via an oil transfer pump. By connecting the drain to an oil transfer pump, oil can be drawn out of the turbocharger, thus preventing oil buildup within the turbocharger and, as a result, preventing unwanted pressure increases within the turbocharger. Furthermore, the limited oil pressure within the turbocharger prevents oil from leaking and entering the exhaust system over the seals, thus protecting the engine from potential damage and preventing a phenomenon known as engine "runaway."

[0083] As a result, by connecting the turbocharger's oil drain to an oil transfer pump, the turbocharger's location can be optimized because gravity is not relied upon to remove oil from within the turbocharger. For example, the lowest point of the turbocharger may be located less than 300 mm above the lowest point of the oil pan during use. More specifically, the turbocharger The lowest point of the turbocharger may be located less than 250 mm above the lowest point of the oil pan during use. More specifically, the lowest point of the turbocharger may be located less than 200 mm above the lowest point of the oil pan during use. For example, the lowest point of the turbocharger may be located between 0 and 300 mm, 100 and 250 mm, 150 and 200 mm, or 160 and 190 mm above the lowest point of the oil pan during use. In this context, "above" means at a higher altitude with respect to the approximate horizontal plane and / or in the direction opposite to gravity.

[0084] The turbocharger may be in fluid communication with an oil reservoir via a turbocharger oil conduit. More specifically, an oil supply pump may be configured to pump oil from the oil reservoir to the turbocharger via the turbocharger oil conduit.

[0085] Placing the turbocharger behind the engine (i.e., behind both the boat and the engine when in use) allows the oil inside to drain under gravity into an oil pickup, where it is then pumped back to the oil reservoir through a separate conduit by an oil supply pump. The use of a pump to assist the gravity-generated oil flow significantly reduces the height above the oil pan where the turbocharger needs to be positioned. This results in a more efficient packaged system that can efficiently incorporate the use of a turbocharger. Furthermore, supplying oil to the turbocharger from within the oil reservoir rather than from the oil pan ensures that the turbocharger always receives oil during use, even when the boat is making sharp turns.

[0086] From here on, the invention will be explained in more detail, simply as an example, with reference to the attached drawings. [Brief explanation of the drawing]

[0087] [Figure 1] This is a schematic diagram of the outboard propulsion system according to the present invention. [Figure 2] Figure 1 shows a transmission assembly as an example of the present invention. [Figure 3] This is a cross-section showing a fixing mechanism, an example of how an outboard propulsion system is attached to the stern of a boat. [Figure 4] This shows an outboard propulsion system with an engine, oil pan, and oil reservoir. [Figure 5] This shows an outboard motor transmission assembly with an oil transfer pump. [Figure 6A] This shows the oil transfer pump as viewed from above. [Figure 6B] The top and side views of the oil transfer pump are shown. [Figure 6C] The bottom and side views of the oil transfer pump are shown. [Modes for carrying out the invention]

[0088] Figure 1 shows one embodiment of an outboard propulsion system 1 comprising a first part 2 and a second part 5. The first part 2 comprises an engine 3 including a crankshaft 4. The engine 3 is configured to generate power and send it to the crankshaft 4. In some embodiments, the engine 3 may be a conventional four-stroke compression-ignition diesel engine; however, any internal combustion engine may be used. In some embodiments, the engine is diesel, while in other embodiments, the engine is gasoline. In some embodiments, the engine is hybrid and comprises at least one battery and at least one electric motor. In some embodiments not shown, the outboard propulsion system is electric and comprises at least one electric motor and an output shaft instead of an engine and crankshaft.

[0089] The longitudinal axis 9 of the crankshaft 4 is parallel to the steering shaft 8. The steering shaft 8 and the longitudinal axis 9 of the crankshaft intersect the longitudinal axis of the boat 40 at an acute angle α of approximately 60 degrees. In some embodiments not shown, the longitudinal axis of the crankshaft may intersect the longitudinal axis of the boat at an acute angle α between 0 and 90 degrees, 20 and 85 degrees, 40 and 80 degrees, 50 and 70 degrees, 55 and 55 degrees, or approximately 60 degrees. Furthermore, the second part 5 comprises an outer propeller shaft 6 and an inner propeller shaft 106, both having longitudinal axes 7 along their length.

[0090] The crankshaft 4 is operably connected to a first intermediate shaft 12 via a spline coupling. The first intermediate shaft 12 is operably connected to a transmission assembly 30. The transmission assembly 30 is operably connected to a second intermediate shaft 14, which is operably connected to a drop shaft 13 via a bevel gear 15. The first intermediate shaft 12 and the second intermediate shaft 14 are substantially parallel to the crankshaft 4. The drop shaft 13 is operably connected to an outer propeller shaft 6 via a first 90-degree bevel gear 17, thus completing the transfer of power between the crankshaft 4 and the outer propeller shaft 6. Furthermore, the drop shaft 13 is operably connected to an inner propeller shaft 106 via a second 90-degree bevel gear 117, thus completing the transfer of power between the crankshaft 4 and the inner propeller shaft 106.

[0091] Alternatively, in some embodiments (not shown), the first intermediate shaft 12 or the second intermediate shaft 14 may be directly connected to the outer propeller shaft 6 via a first bevel gear configured to transmit power to the outer propeller shaft 6. The first intermediate shaft 12 or the second intermediate shaft 14 may further be directly connected to the inner propeller shaft 106 via a second bevel gear configured to transmit power to the inner propeller shaft 106.

[0092] In some embodiments not shown, a single propeller shaft may be present, and the first intermediate shaft 12 or the second intermediate shaft 14 may be directly connected to the propeller shaft via bevel gears configured to transmit power to the propeller shaft.

[0093] Alternatively, in some embodiments (not shown), the crankshaft 4 may be directly connected to at least one propeller shaft via bevel gears configured to transmit power to at least one propeller shaft. For example, the crankshaft 4 may extend from the engine 3 through the first section 2 into the second section 5 and be connected to at least one propeller shaft via at least one bevel gear.

[0094] As shown in Figure 1, the drive shafts comprise a drop shaft 13, a first intermediate shaft 12, and a second intermediate shaft 14. The drop shaft 13 is approximately perpendicular to the outer propeller shaft 6 and the inner propeller shaft 106, and is configured to transmit power from the crankshaft 4 to the inner propeller shaft 106 and the outer propeller shaft 6.

[0095] The second intermediate shaft 14 is movably connected between the first intermediate shaft 12 and the drop shaft 13. The second intermediate shaft 14 is substantially parallel to the longitudinal axis 9 of the crankshaft and is movably connected to the drop shaft 13 via a bevel gear 15.

[0096] The second part 5 is configured to pivot relative to the first part 2 around the steering shaft 8. The steering shaft 8 extends approximately parallel to the longitudinal axis 9 of the crankshaft and intersects the longitudinal axis of the propeller shaft 7 at an obtuse angle β between 100 and 140 degrees. In Figure 1, shaft 8' is parallel to the steering shaft and offset from it, and the obtuse angle β is shown as an example for clarity. It is used for this purpose. Preferably, the steering shaft 8 (and offset shaft 8') intersects the longitudinal axis of the propeller shaft 7 at an angle β of approximately 120 degrees.

[0097] Furthermore, the outer propeller shaft 6 includes a first propeller 16 configured to receive power from the outer propeller shaft 6 during use and generate thrust to drive the boat through a fluid such as water. The inner propeller shaft 106 includes a second propeller 116 configured to receive power from the inner propeller shaft 106 during use and generate thrust to drive the boat through a fluid such as water.

[0098] In some embodiments not shown, the inner propeller shaft and / or outer propeller shaft comprises multiple propellers.

[0099] The outboard propulsion system further comprises a transmission assembly 30 configured to control the power supplied to the propeller shaft.

[0100] Figure 2 shows a transmission assembly of the present invention. The transmission assembly 30 comprises a forward gear set 34 and a reverse gear 32 configured to control the speed and / or direction of power supplied to the propeller shaft. The transmission assembly also comprises a forward clutch 37 configured to enable the forward gear set 34 and a reverse clutch 36 configured to allow the reverse gear to be engaged in a switchable manner. The transmission assembly 30 is located in the first part 2. However, in some embodiments (not shown), the transmission assembly may be located in the second part 5.

[0101] Furthermore, the transmission assembly includes an offset pair of offset gears 38 configured to move the second portion closer to the stern of the boat by a distance X. The distance X is approximately 105–110 mm, for example, 107 mm. In some embodiments not shown, X may be 0–1000 mm, 20–500 mm, 50–300 mm, 70–200 mm, 80–150 mm, or 100–120 mm.

[0102] Figure 3 shows a cross-section passing through the fixing mechanism 11, which is taken from the side elevation of the fixing mechanism approximately 5 to 250 mm away, passing through a plane parallel to the longitudinal axis 40 of the boat. The fixing mechanism 11 is configured to attach the first part of the outboard propulsion system to the transom of the boat. Furthermore, the fixing mechanism is configured to tilt the first part 2 and the second part 5 together around a rotation axis 10 that is approximately parallel to the stern of the boat.

[0103] The fixing mechanism 11 comprises a cradle 21 for mounting to the first part 2 and a transom bracket 22 for mounting to the boat's transom. The cradle 21 is fixed to the first part 2 via a number of bolts configured to prevent relative movement between it and the first part 2. The cradle is bolted to the housing of the transmission assembly 30. Thus, the first part is fixed around a substantially vertical axis 42. In some embodiments not shown, the first part may be fixed around a substantially vertical plane.

[0104] The transom bracket 22 is configured to be attached to the stern of the boat via a number of bolts, screws, and / or clamps configured to connect the two components together by passing through the transom of the boat and the transom. The cradle 21 and the transom bracket 22 are operably connected via a rotary joint 25 configured to allow a single pivot axis 10 substantially parallel to the stern of the boat.

[0105] The rotary joint 25 shown in the cross-section of Figure 3 comprises a single rotary joint. In some embodiments (not shown), the complete stationary mechanism 11 may comprise at least two separate coaxial rotary joints. Each rotary joint comprises a spindle less than 500 mm in length. More preferably, the spindle may be less than 400 mm, less than 300 mm, or less than 200 mm in length, and most preferably, the spindle is less than 100 mm in length, for example, 65 mm.

[0106] The fixing mechanism 11 further comprises a hydraulic arm 28 operably connected between the cradle 21 and the transom bracket 22, as shown in the cross section of Figure 3. The hydraulic arm 28 is configured to rotate the cradle relative to the transom bracket, and thereby rotate the outboard propulsion system 1 around the pivot axis 10 relative to the boat's transom. This rotation can be used to trim and / or tilt the outboard propulsion system. In some embodiments (not shown), the complete fixing mechanism may include a second hydraulic arm positioned opposite the fixing mechanism so that the fixing mechanism is symmetrical about a vertical axis. The second hydraulic arm may assist in trimming and / or tilting a heavy marine propulsion system and / or allow two smaller hydraulic arms to replace one larger component. Furthermore, in some embodiments (not shown), the fixing mechanism may comprise multiple hydraulic arms, up to 2, 3, 4, 5, 8, or 10 hydraulic arms, or more than 10 hydraulic arms.

[0107] The (one or more) hydraulic arms 28 are operably connected to an electronic control unit configured to extend and retract the hydraulic arms to control the movement of the cradle relative to the transom bracket. The control unit can be operated by a user such as the boat's captain, driver, and / or crew.

[0108] Figure 4 shows an outboard propulsion system 1 including an engine 3 having a crankcase 60 with a crankshaft 4. The outboard propulsion system 1 further includes an oil pan 65 and an oil reservoir 70. The engine 3 is configured to receive oil from the oil reservoir 70. When in use, an oil transfer pump 80 pumps oil from the oil pan 65 into the oil reservoir 70 through at least one conduit. In addition, an oil supply pump, not shown in the accompanying drawings, pumps oil from the oil reservoir 70 into the engine 3 through at least one conduit. The oil supply pump is powered via a chain or belt operably connected to the crankshaft 4. Thus, as the rotational speed of the crankshaft 4 increases, the oil supply pump receives more rotational energy, and therefore the amount of oil supplied to the engine per unit time increases. Alternatively, in some embodiments, the oil supply pump is operably connected to a pump shaft 82 and therefore receives power from there.

[0109] Excess oil in engine 3 is collected in oil pan 65. The oil pan 65 is located substantially below engine 3 during use. More specifically, the oil pan 65 is located substantially below crankcase 60 during use. As a result, oil in the engine and / or crankcase flows towards the oil pan under gravity. During use, the oil in oil pan 65 is then transferred to oil reservoir 70 via oil transfer pump 80.

[0110] In some embodiments, the outboard propulsion system 1 further includes an oil filter. The oil filter is positioned so that the oil flowing from the oil reservoir 70 to the engine 3 passes through the filter. The filter is configured to remove contaminants such as metal particles from the oil. This also increases the efficiency by which the engine can generate power. The outboard propulsion system 1 further includes an oil cooler. The oil cooler is positioned so that the oil flows through the oil reservoir 70 It is located between the oil supply pump and the oil filter. More specifically, the oil cooler is located between the oil supply pump and the oil filter. As a result, the oil flowing from reservoir 70 to engine 3 is cooled and then filtered.

[0111] The oil reservoir 70 includes an oil pickup configured to receive oil and transfer it into the engine. The oil pickup is in fluid communication with the engine 3 via at least one conduit. More specifically, the oil pickup is in fluid communication with the engine 3 via an oil supply pump. Preferably, the oil pickup is located towards the bottom of the oil reservoir 70. Having the oil pickup located towards the bottom of the oil reservoir during use ensures that the oil pickup remains submerged in oil during use. This is particularly advantageous when the outboard propulsion system is turned away from the horizontal plane, such as when turning a corner.

[0112] The oil reservoir 70 is located in front of the engine, as shown in Figure 4. Therefore, when in use, the oil reservoir 70 is located between the engine 3 and the boat. Alternatively, in some embodiments, the oil reservoir is located behind or above the engine. Therefore, the oil reservoir 70 can be located in any desired position.

[0113] More specifically, as shown in Figure 4, the oil reservoir is located directly adjacent to the engine. For example, the oil reservoir may be positioned to optimize the weight distribution of the outboard propulsion system and / or to improve the overall packaging of the system.

[0114] In some embodiments, the engine 3 includes an internal wall 72 configured to separate the crankcase 60 from the oil reservoir 70. As a result, the respective boundaries of the crankcase 60 and the oil reservoir 70 are defined by the internal wall 72. The internal wall 72 further includes an opening 74 configured to balance the pressure between the crankcase 60 and the oil reservoir 70. The opening 74 is located towards the top of the oil reservoir 70 when in use. Thus, the opening 72 and the oil pickup are located at opposite ends of the oil reservoir 70.

[0115] Figure 5 shows an outboard motor transmission assembly 30 with an oil transfer pump 80. The oil transfer pump 80 is configured to receive power directly from the transmission assembly 30 in the form of rotational energy. More specifically, the engine 3 rotates the crankshaft 4 around its longitudinal axis, which in turn rotates the first intermediate shaft 12 and / or input shaft 12. The oil transfer pump 80 includes a pump shaft 82 connected to the first intermediate shaft 12 and / or input shaft. More specifically, the first intermediate shaft 12 and / or input shaft is directly connected to a reversing gear 32 and a reversing clutch 36, and the pump shaft 82 is directly connected to a forward gear 34 and a forward clutch 37. Alternatively, in some embodiments, the pump shaft 82 is directly connected to the first intermediate shaft 12 and / or input shaft. On the other hand, in some embodiments, the pump shaft 82 is connected to the first intermediate shaft 12 and / or input shaft via at least one additional shaft.

[0116] The pump shaft 82 is configured to rotate at all times during use. For example, the pump shaft is configured to rotate at all times when the engine 3 is turned on. More specifically, the pump shaft 82 is operably connected to the crankshaft 4. As a result, as the rotational speed of the crankshaft increases, the rotational speed of the pump shaft increases. However, there may be at least one gear configured to increase and / or decrease the rotational speed of the pump shaft 82 with respect to the crankshaft 4. In any case, As the rotational speed of the crankshaft 4 increases, the rotational speed of the pump shaft increases, and therefore the speed at which oil is transferred from the oil pan 65 to the oil reservoir 70 increases.

[0117] The engine, crankcase, oil pan, oil reservoir, turbocharger, and the conduits between them may contain a total of 3 to 20 liters of oil. More specifically, the engine, crankcase, oil pan, oil reservoir, turbocharger, and the conduits between them may contain a total of 5 to 15 liters of oil. Most specifically, the engine, crankcase, oil pan, oil reservoir, turbocharger, and the conduits between them may contain a total of 7 to 11 liters of oil. For example, in some embodiments, the engine, crankcase, oil pan, oil reservoir, turbocharger, and the conduits between them contain a total of 8 to 10 liters of oil.

[0118] In some embodiments, during use, the engine receives between 30 and 150 liters of oil per minute. More specifically, the engine receives between 35 and 60 liters of oil per minute. Most specifically, the engine receives between 40 and 45 liters of oil per minute. The oil supply pump is configured to deliver the aforementioned oil flow rates to the engine via a conduit. Alternatively, in some embodiments, the oil transfer pump 80 may pump fluid from the oil pan to the oil reservoir at a rate of up to 1,000 liters per minute. The fluid may consist of air and oil.

[0119] Alternatively or additionally, the oil transfer pump 80 is configured to pump oil from the oil pan 65 to the oil reservoir 70 at a rate of 100 to 140 liters per minute. More specifically, the oil transfer pump 80 is configured to pump oil from the oil pan 65 to the oil reservoir 70 at a rate of 110 to 130 liters per minute. Most specifically, the oil transfer pump 80 is configured to pump oil from the oil pan 65 to the oil reservoir 70 at a rate of 115 to 125 liters per minute. Thus, the oil transfer pump 80 may be configured to draw air from within the engine and deliver it to the oil reservoir 70. Thus, the oil transfer pump 80 may be configured to create a partial vacuum within the engine 3.

[0120] In some embodiments, the oil transfer pump 80 is configured to create a partial vacuum within the crankcase 60. This ensures that substantially all of the oil in the crankcase is emptied into the oil reservoir 70 when the engine 3 is turned off. The air pressure in the crankcase may be less than 1 bar during use. More specifically, the air pressure in the crankcase may be less than 0.75 bar during use. Most specifically, the air pressure in the crankcase may be less than 0.5 bar during use. However, in some embodiments, the air pressure in the crankcase is less than 0.4 bar during use.

[0121] A partial vacuum within the engine and / or crankcase reduces air resistance to the crankshaft as it rotates during operation. Furthermore, a partial vacuum in the crankcase prevents excess oil from contacting the crankshaft during operation. This can improve engine efficiency by up to 3%.

[0122] Figure 6A shows the oil transfer pump 80 as viewed from above, Figure 6B shows the top and side views of the oil transfer pump 80, and Figure 6C shows the bottom and side views of the oil transfer pump 80.

[0123] More specifically, the oil transfer pump 80 includes a rotor 84 configured to transfer oil from an inlet port to an outlet port within the transfer pump 80. The rotor 84 is double It is a dual-filled rotor. Therefore, the oil transfer pump 80 is The oil transfer pump 80 includes a first inlet 86 configured to receive oil from the Ilpan 65. The first inlet 86 is located at the first end of the oil transfer pump 80. More specifically, the first inlet 86 is located at the first end of the rotor 84. For example, the first inlet 86 is located towards the top of the oil transfer pump 80 when in use. The oil transfer pump 80 further includes a second inlet 88 configured to receive oil from the turbocharger. The second inlet 88 is located at the second end of the oil transfer pump 80. More specifically, the second inlet 88 is located at the second end of the rotor 84. For example, the second inlet 88 is located towards the bottom of the oil transfer pump 80 when in use. Thus, the first and second ends of the oil transfer pump are opposite each other. More specifically, the first inlet 86 is located at the top of the oil transfer pump and the second inlet 88 is located towards the bottom of the oil transfer pump. The oil transfer pump 80 further includes an outlet position between the first and second inlets. The outlet is in fluid communication with the oil reservoir 70. As a result, the turbocharger drain, oil pump inlet, oil pump outlet, and corresponding oil conduits can be sized to optimize engine performance.

[0124] The outboard propulsion system further comprises a seal 87 configured to provide a substantially liquid-tight seal between the transmission assembly and the engine. More specifically, the outboard propulsion system further comprises a seal 87 configured to provide a substantially liquid-tight seal between the transmission assembly and the engine 3. Most specifically, the outboard propulsion system further comprises a seal 87 configured to provide a substantially liquid-tight seal between the transmission assembly and the crankcase 60. The seal 87 is a lip seal. However, any suitable seal may be used.

[0125] In view of this disclosure, various further aspects and embodiments of the present invention will become apparent to those skilled in the art.

[0126] Where used herein, “and / or” should be interpreted as specifically disclosing each of two identified features or components, regardless of the presence or absence of the other. For example, “A and / or B” should be interpreted as specifically disclosing each of (i) A, (ii) B, and (iii) A and B, as if each were shown separately herein.

[0127] Unless otherwise indicated by the context, the descriptions and definitions of features set forth above are not limited to any particular aspect or embodiment of the invention, but apply equally to all aspects and embodiments described herein.

[0128] While the invention has been described as an example with reference to several embodiments, it will be further understood by those skilled in the art that the invention is not limited to the disclosed embodiments, and that alternative embodiments can be constructed without departing from the scope of the invention as defined by the accompanying claims. [Explanation of symbols]

[0129] 1. Outboard propulsion system 2 Part 1 3 Engines 4 Crankshaft 5 Part 2 6. Outer propeller shaft 7. Longitudinal axis of the propeller shaft 8. Steering shaft 8' Offset axis 9. Longitudinal axis of the crankshaft 10 Rotation axis 11 Fixing mechanism 12. First Intermediate Shaft 13 Drop shaft 14. Second Intermediate Shaft 15 Bevel Gear 16. First propeller 17. First 90-degree bevel gear 21 Cradle 22 Transom Bracket 25 Rotary joint 28 Hydraulic Arm 30 Transmission Assembly 32 Reverse gear 34 Forward Gear Set 36 Reverse clutch 37 Forward clutch 40 Longitudinal axis of a boat 42 Approximately vertical axis 60 Crankcase 65 Oil pan 70 Oil reservoir 72 Internal wall 74 Aperture 80 Oil transfer pump 82 Pump shaft 84 Rotor 86 Entrance 1 87 Seals 88 Second Entrance 106 Inner propeller shaft 116. Second propeller 117 Second 90-degree bevel gear α The angle of the steering axis and the longitudinal axis of the crankshaft relative to the longitudinal axis of the boat. β Angle of the steering axis relative to the longitudinal axis of the propeller shaft X Distance that can be approached towards the stern

Claims

1. A first part for attachment to a boat with a stern, comprising a first part including an engine with a crankshaft; A second part comprising at least one propeller shaft having a longitudinal axis along its length; In an outboard propulsion system equipped with, The at least one propeller shaft is operably connected to the crankshaft via at least one drive shaft configured to transmit power to the crankshaft, The at least one drive shaft includes a drop shaft, and the drop shaft is substantially perpendicular to the at least one propeller shaft. The second part is configured to pivot relative to the first part around the steering axis, The steering shaft intersects the longitudinal axis of the at least one propeller shaft at an obtuse angle. The first and second parts are configured to tilt integrally around a single axis of rotation substantially parallel to the stern of the boat, An external propulsion system in which the first part is fixed around a substantially vertical axis.

2. An outboard propulsion system according to claim 1, An outboard propulsion system further comprising a fixing mechanism configured to attach the first portion to the stern of the boat, wherein the fixing mechanism is configured to allow only a single axis of rotation.

3. In the outboard propulsion system according to claim 1 or 2, An outboard propulsion system in which at least one drive shaft comprises a first intermediate shaft operably connected between the crankshaft and the drop shaft, the first intermediate shaft operably connected to the drop shaft via a first bevel gear.

4. In the outboard propulsion system according to claim 3, An outboard propulsion system in which the first intermediate shaft is substantially parallel to the longitudinal axis of the crankshaft.

5. In the outboard propulsion system according to any one of claims 1 to 4, A hull propulsion system in which the steering shaft extends substantially parallel to the longitudinal axis of the crankshaft.

6. An outboard propulsion system according to any one of claims 1 to 5, An outboard propulsion system in which the at least one drive shaft is operably connected to the at least one propeller shaft via a first bevel gear.

7. An outboard propulsion system according to any one of claims 1 to 6, An outboard propulsion system further comprising a transmission assembly configured to control the power supplied to the at least one propeller shaft.

8. In the outboard propulsion system according to claim 7, The transmission assembly is located in the first part of the outboard propulsion system.

9. In the outboard propulsion system according to claim 7 or 8, An outboard propulsion system comprising, the transmission assembly further, a pair of offset gears configured to bring the second portion closer to the fixing mechanism.

10. In the outboard propulsion system according to any one of claims 1 to 9, An outboard propulsion system in which the steering shaft intersects the longitudinal axis of the at least one propeller shaft at an angle between 100 and 140 degrees.

11. In the outboard propulsion system according to any one of claims 1 to 10, An outboard propulsion system in which the steering shaft intersects the longitudinal axis of the at least one propeller shaft at an angle of approximately 120 degrees.

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