Claims:CLAIMS:
We Claim:
1. A bearing housing assembly for boat propulsion systems, comprising:
a housing;
a drive unit positioned within said housing where said drive unit and the housing are positioned on a hull of a long-tail boat;
a drive shaft extending from said drive unit;
a power transmission shaft placed near said drive unit extend parallel to said drive shaft;
a transmission means configured to transfer mechanical power from said drive shaft to said power transmission shaft;
a first bearing assembly comprising an axial bearing, a first housing unit, a shaft seal, and a first lock nut positioned axially on first end of said power transmission shaft, configured to withstand axial thrust produced along said power transmission shaft, and
a second bearing assembly comprising a radial bearing, a second housing unit, and a second lock nut positioned on second end of said power transmission shaft, configured to withstand radial loads produced by transmission member from said drive unit to said power transmission shaft;
wherein said bearing housing assembly configured to withstand large axial thrust as well as radial loads produced in the long-tail boats.
2. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein a provision is provided on said housing for said power transmission shaft to connect to said long-tail shaft.
3. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said power transmission shaft is a stepped shaft to accommodate within said bearing assembly.
4. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said power transmission shaft configured with a spline coupling arrangement on said first end of said power transmission shaft to couple said long-tail shaft.
5. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said transmission means may comprise either a belt or chain drive or other similar transmission means to achieve required power transmission from said drive unit to said power transmission shaft.
6. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said drive shaft and said power transmission shaft are configured with plurality of pulleys to accommodate said transmission means and to rotate on said pulleys.
7. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said axial bearing comprises a double angular contact bearing or any other similar bearings to withstand axial thrust.
8. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said radial bearing comprises a deep groove ball bearing or any other similar bearings to withstand radial loads.
9. The bearing housing assembly for boat propulsion systems as claimed in claim 1, wherein said housing unit comprises at least two spacer’s to accommodate said bearing assembly with right tolerance and close fit. , Description:DESCRIPTION:
Field of the invention:
[0001] The present disclosure generally relates to the technical field of a power transmission shaft in boat propulsion systems supported by a bearing system, and in specific relates to a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft and with airtight arrangement to increase the life span of bearings and prevent corrosion and rust. This bearing assembly keeps the shaft in position, at the same time transfer the axial thrust to the main assembly which is mounted on the boat.
Background of the invention:
[0002] The long-tail boat, is a type of watercraft which uses a common automotive internal combustion engine. It is classified in genus high speed vessel because operating velocity is much higher. Long-Tail Boats are often used to transport passengers and tourists. Gasoline, diesel and electric engines are prime movers for the propulsion of long-tail boats.

[0003] A hollow tube carrying the long-tail shaft from the driving unit in long-tail boats is known as stern tube. The stern tube should be of sufficient length to suit the particular boat in which it is to be installed. The stern tube connected to the drive unit housing to take up the axial load of the power transmission shaft. The propulsion shaft with stern tube directly connected to the driving unit for transfer of power to a propeller with the help of bearing unit. However, the bearing unit with the power transmission shaft is installed outside of the drive unit. Due to corrosive environment the bearing unit and the power transmission shaft tends to wear out fast, causes considerable wear on the tail shaft as well.

[0004] Over the last few years, there is a spike in the development of electric boats (E-boat). To deliver sufficient power to the propeller, the propulsion shaft is directly connected to the drive unit. Outside the drive unit housing, a bearing housing is placed during the design phase. Whereby, the bearing housing's installation and maintenance are quite simple. Bearing sealing installation, on the other hand, frequently yields poor results, as water goes into the bearing housing due to improper sealing causes significant wear on the bearing unit.

[0005] Due to tiny hull size and lack of space, the majority of long-tail boats employ small engines with direct drive. Installation of an auxiliary housing for the propeller shaft in long tail boats would be inconvenient. As a result, a bearing unit connects the driving unit to the propulsion shaft, which is located outside the housing. It causes the bearing housing to wear out and necessitates maintenance aspects. The poor wearability of bearing housing due to the corrosive environment has an impact on the operation's progress. Further, the bearing unit lubricating oil solidification occurs due to expose of bearing unit to the environment.

[0006] In existing technology, the thrust shaft is the primary shaft emerging out of the engine in the boats. In high-speed engines, it receives rotational motion straight from the engine and rotates at maximum speed. The thrust shaft is directly connected to the engine via the u-joint in high-rpm engines. Large thrust forces or shocks act on the entire propeller shaft while the boat is in operation. Because of their weight, this force tends to deform and damage components. Large vibrational shocks that act on the propeller shafts are immediately transferred to the drive unit when the long tail shaft is directly linked with the drive unit utilizing a u-joint. Wherein the back thrust or vibrational shocks leads the propeller shafts and driving unit might damage permanently.

[0007] As noted previously, traditional bearing housing is installed on the outside of the boat hull, which causes various phenomenon. The phenomenon such as corrosion and lubricating oil solidification which leads to a life-time service process, because that bearing is stuck, in order to prevent corrosion, reduce friction, increase the service life, and reduce production cost, it is necessary to adopt the bearing housing being placed in the airtight enclosure and proper sealing is required.

[0008] Therefore, there is a need for a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft and with airtight arrangement to increase the life span of bearings and prevent corrosion and rust. There is a requirement of unified housing for both drive unit and power transmission shaft to eliminate the use of extra housing for power transmission shaft. Further, there is a need for a sealing device of a bearing unit, to prevent corrosion and rust and increase the life span of bearing unit. There is a need for the system where the bearing assembly is protected from corrosion, avoid back thrust or shock from water to the drive system during operation. There is a need of bearing assembly which can take large thrust force produced as well as shocks, without damaging any other component.
Objectives of the invention:
[0009] The primary objective of the invention is to provide a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft with an air tight housing for power transmission shaft and a bearing unit in long-tail boats.

[0010] Another objective of the invention is to provide an optimized housing for the bearing unit, and the housing's outer perimeter has been reduced to fit on long-tail boats.

[0011] The other objective of the invention is to provide with a bearing mechanism to take up the axial and radial load produced along the power transmission shaft in long-tail boats.

[0012] Yet another objective of the invention is to provide a bearing assembly that is enclosed in a drive unit housing to eliminate extra housing needed for the power transmission shaft in the long-tail boats.

[0013] Further objective of the invention is to increase the life span of the bearings and the power transmission shaft due to non-corrosive environment in the housing.

[0014] Another objective of the invention is to provide a shaft sealing to protect the bearing assembly from dust, water and prevent the contamination and corrosion of the housing and assembly.

[0015] The other objective of the invention is to provide a stepped shaft for accommodating a bearing unit with different loading capacity can be easily mounted for wide range of applications.

Summary of the invention:
[0016] The present disclosure proposes bearing housing assembly for boat propulsion systems. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0017] In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft and with airtight arrangement to increase the life span of bearings and prevent corrosion and rust.

[0018] According to an aspect, the invention provides a bearing housing assembly for boat propulsion systems. The bearing housing assembly comprising a housing, a drive unit, a drive shaft, a power transmission shaft, a transmission means, a first bearing assembly and a second bearing assembly. The drive unit positioned within the housing, where the drive unit and the housing are positioned on a hull of a long-tail boat. The housing unit is provided with a provision for the power transmission shaft to connect with the long-tail shaft.

[0019] The power transmission shaft is a stepped shaft to accommodate within the bearing assembly. The power transmission shaft placed near the drive unit extend parallel to the drive shaft. The first bearing assembly includes an axial bearing, a first housing unit, a shaft seal, and a first lock nut. The first bearing assembly positioned axially on the first end of the power transmission shaft and is configured to withstand axial thrust produced along the power transmission shaft. The power transmission shaft configured with a spline coupling arrangement on the first end to couple the long-tail shaft.

[0020] The second bearing assembly is comprising with a radial bearing, a second housing unit, and a second lock nut. The second bearing assembly, positioned on the second end of the power transmission shaft, and is configured to withstand radial loads produced by the transmission member from the drive unit to the power transmission shaft. The axial bearing comprises a double angular contact bearing or any other similar bearings to withstand axial thrust. Whereas, the radial bearing comprises a deep groove ball bearing or any other similar bearings to withstand radial loads. The housing unit comprises at least two spacers to accommodate the bearing assembly with accurate tolerance and close fit.

[0021] The drive shaft is extended from the drive unit. The transmission means is configured to transfer mechanical power between the drive shaft and the power transmission shaft. The transmission means is comprising either a belt or chain drive or other similar transmission means to achieve required power transmission from the drive unit to the power transmission shaft. The drive shaft and the power transmission shaft utilizing timing pulleys to accommodate the transmission means and the transmission means rotate on the pulleys and deliver power from the drive unit to the long-tail propulsion shaft.

[0022] Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
[0023] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.

[0024] FIG. 1A illustrates an exemplary cross-sectional view of an electric propulsion system of a long-tail boat in accordance to an exemplary embodiment of the invention.

[0025] FIG. 1B illustrates an exemplary isometric view of a stepped shaft in accordance to an exemplary embodiment of the invention.

[0026] FIG. 2 illustrates an exemplary isometric view of a stepped shaft with a bearing housing assembly in accordance to an exemplary embodiment of the invention.

[0027] FIG. 3A illustrates an exemplary cross-sectional view of a stepped shaft with a bearing housing assembly in accordance to an exemplary embodiment of the invention.

[0028] FIG. 3B illustrates an exemplary isometric view of bearing assembly housings in accordance to an exemplary embodiment of the invention.
Detailed invention disclosure:
[0029] Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.

[0030] The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft and with airtight arrangement to increase the life span of bearings and prevent corrosion and rust.

[0031] According to an exemplary embodiment of the invention, FIG. 1A refers to an exemplary cross-sectional view of an electric propulsion system 100 of a long-tail boat. The electric propulsion system 100 comprises a housing 102, a drive unit 104, a drive shaft 106, a transmission means 110, a power transmission shaft 114, a first bearing assembly 118 and a second bearing assembly 116. The drive unit 104 enclosed in the robust housing 102 is capable of delivering the required power without interruption.

[0032] The drive unit 104 is managed by a battery management system. The power received from the rechargeable battery packs is used to accelerate and steer the long-tail boats using a controller located near the drive unit 104. The drive unit 104 is designed to be easily mounted on the rear/on one end of the boat and to provide the required thrust needed to drive the boat. The housing 102 is provided with a provision for the power transmission shaft 114 to connect to the long-tail shaft 120. The drive unit 104 further comprises the drive shaft 106 extending from the drive unit 104. The free end of the drive shaft 106 comprise a pulley 108.

[0033] The power transmission shaft 114 as shown in FIG. 1B refers to a stepped shaft to accommodate within the bearing assembly. The stepped shaft 114 is positioned in the housing 102, near the drive unit 104 extend parallel to the drive shaft 106. The stepped shaft 114 is configured with a spline coupling arrangement on the first end 122 to couple the long-tail shaft 120. The second end 124 is configured with a pulley 112 for rotation of stepped shaft 114 by means of a transmission means 110.

[0034] The transmission means 110 configured to transfer mechanical power between the drive shaft 106 and the stepped shaft 114. The transmission means 110 may comprise either a belt or chain drive or other similar transmission means. The belt drive 110 passes over the pulleys 108 and 112 to achieve required power transmission between the drive unit 104 and the stepped shaft 114. The belt drive 110 configured to withstand high tensile stress, high flexibility and low rigidity. High coefficient of friction between belt drive 110 and the pulleys 108 and 112. The belt drive 110 have excellent resistance to wear and fatigue to transfer power from the drive unit 104 to the stepped shaft 114.

[0035] According to another exemplary embodiment of the invention, FIG. 2 refers to an exemplary isometric view of a stepped shaft with a bearing housing assembly 200. The bearing assembly 200 is the part of the boat propulsion system. It transfers the rotational power from the motor shaft to the long tail shaft and act as coupler. The assembly 200 comprises a stepped shaft 214, a second bearing assembly 216 and a first bearing assembly 218. The main purpose of this assembly 200 is to take up the axial as well radial load produced along the stepped shaft 214.

[0036] As the propeller of the ship rotates, it generates large axial thrust along the long-tail propulsion shaft axis. This axial thrust produced has to be transferred from the long-tail propulsion shaft to the stepped shaft 214 and to the boat. The first end of the stepped shaft 214 is configured with a spline coupling arrangement 222. The first bearing assembly 218 configured to withstand those axial thrusts produced along the stepped shaft 214 first end. On the other end 224 the stepped shaft 214 has radial forces, acting due to tension in the belt drive, this is taken care of with the second bearing assembly 216.

[0037] According to another exemplary embodiment of the invention, FIG. 3A refers to an exemplary cross-sectional view of a stepped shaft with a bearing housing assembly 300. The assembly 300 comprises a stepped shaft 314, a second bearing assembly 316 and a first bearing assembly 318. The stepped shaft 314 enclosed inside the housing placed near the drive unit extend parallel to the drive shaft. The stepped shaft 314 supported by the first bearing assembly 318 positioned on first end. On the other end of stepped shaft 314 supported by the second bearing assembly 316.

[0038] The first bearing assembly 318 comprises a first housing unit 318A, as shown in FIG. 3B, an axial bearing 318B, a first lock nut 318C and a shaft seal 318D positioned axially on the first end of the stepped shaft 314. The first housing unit 318A, primarily composed of an axial bearing 318B. The axial bearing 318B is comprising a double angular contact bearing or any other similar bearings to withstand axial thrust. The double angular contact bearing 318B is capable to withstand large axial load.

[0039] As the propeller of the ship rotates, it generates large axial thrust along the shaft axis. This axial thrust produced has to be transferred from the shaft to the stepped shaft 314 and to the boat. The double angular contact bearing utilized to take up large axial thrust. Further, the shaft seal 318B is utilized to protect the first bearing assembly 318 from dust and water and prevent the contamination and corrosion of the first housing unit 318A. The first lock nuts 318C, positioned near the double angular contact bearing 318B, configured to hold the bearing 318B tightly into the first housing unit 318A.

[0040] The first lock nut 318C is tightly screwed into the stepped shaft 314. If the stepped shaft 314 moves axially, first lock nut 318C moves along with it and transfers the axial load to the double angular contact bearing 318B. The first lock nut 318C plays a crucial role to arrest the axial movement of stepped shaft 314 and transfer the load to the double angular contact bearing 318B. The first lock nut 318C transfers the axial load to the double angular contact bearing 318B. This bearing 318B keeps the stepped shaft 314 in position, at the same time transfer the axial thrust to the main assembly which is mounted on the boat.

[0041] The second bearing assembly 316 comprises a second housing unit 316A, as shown in FIG. 3B, a radial bearing 316B and a second lock nut 316C positioned on the second end of the stepped shaft 314. The radial bearing 316B comprises a deep groove ball bearing or any other similar bearings to withstand radial loads. The deep groove ball bearing 316B positioned in the second housing unit 316A. The second lock nut 316C, positioned near the deep groove ball bearing 316B, configured to hold the bearing 316B tightly into the second housing unit 316A.

[0042] The second lock nut 316C is tightly screwed into the stepped shaft 314. While transferring power from drive unit to stepped shaft 314 through a belt drive, radial forces are generated. During rotation of the belt drive, radial forces are generated on the second end of the stepped shaft 314. These radial forces of the stepped shaft 314 are transferred to the deep groove ball bearing 316B. This bearing 316B keeps the stepped shaft 314 in position at the same time it takes up the radial load which acts along the shaft due to tension in the belt drive.

[0043] According to another exemplary embodiment of the invention, FIG. 3B refers to an exemplary isometric view of bearing assembly 300 housings. The first housing unit 318A and the second housing unit 316A configured with at least one spacer to accommodate the bearings, lock nuts and the stepped shaft with right tolerance and close fit.

[0044] Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, a bearing assembly which transfers rotational power from the motor shaft to the long tail shaft and an airtight housing for power transmission shaft and bearing unit in long-tail boats. The system is provided with an optimized housing for the bearing unit, and the housing's outer perimeter has been reduced to fit on long-tail boats. The system with a bearing mechanism to take up the axial and radial load produced along the power transmission shaft in long-tail boats.

[0045] The bearing assembly that is enclosed in a drive unit housing to eliminate extra housing needed for the power transmission shaft in the long-tail boats. This housing increase the life span of the bearing assembly and the power transmission shaft due to non-corrosive environment in the housing. The system provide with a sealing to protect the bearing assembly from dust, water and prevent the contamination and corrosion of the housing and bearing assembly. A stepped shaft is provided for accommodating a bearing assembly with different loading capacity to mount easily for wide range of applications.

[0046] According to another exemplary embodiment of the invention, the shaft seals may have good air-tightness and water-tightness, good bonding performance, heat resistance and aging resistance, certain elasticity and plasticity, as well as good tension-compression cycling performance to withstand in any conditions. The bearing housing may have modular assemblies designed to make it easy to install bearings on the shaft. The bearing housing may comprise either split plummer (or pillow) block housings, non-split plummer block housings, flanged housings, take-up housings and two-bearing housings based on the parameters such as load, speed and operating environmental conditions.

[0047] It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.