Multi-stage propeller propelling system of ship

Abstract

The utility model discloses a ship multistage propeller propulsion system which comprises a fixed shaft, a leading propeller, a medium pressure propeller and a tail end propeller are sequentially arranged on the fixed shaft, the leading propeller, the medium pressure propeller and the tail end propeller are respectively provided with a blade and an installation shell, a hub motor is arranged between the installation shell and the fixed shaft, and the hub motor is connected with the fixed shaft. The hub motor comprises a rotating shell, the rotating shell is fixedly connected with the mounting shell, the rotating shell is rotationally connected to the fixed shaft, and by means of the ship multi-stage propeller propelling system, propelling efficiency is improved, cavitation corrosion is reduced, and maintenance is convenient.

Description

Technical Field

[0001] This utility model belongs to the field of ship propulsion systems, specifically, it relates to a multi-stage propeller propulsion system for ships. Background Technology

[0002] Most existing ship propulsion systems are single-propeller structures, which cannot achieve multi-stage energy transfer. Furthermore, large-diameter single propellers are prone to cavitation corrosion under high-speed conditions and have poor thrust linearity at low speeds (such as a sharp drop in efficiency when a tugboat is moored and towing). A few existing ship propulsion systems are ducted propellers, which can delay cavitation to some extent, but their axial dimensions are too large and they are not easy to maintain.

[0003] Utility model patent CN210455161U, published on May 5, 2020, discloses a multi-stage propeller ship propulsion device. It comprises a propeller housing, a conventional propeller, and a hub motor propulsion unit. The conventional propeller is fixedly mounted on the inlet side, and the hub motor driver is fixedly mounted on the outlet side. The conventional propeller includes a propeller, a gearbox, and a boom. The hub motor propulsion unit consists of a stator assembly fixed to the propeller housing and a cooperating propeller rotor assembly. However, this multi-stage propeller ship propulsion device does not solve the aforementioned technical problems. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a multi-stage propeller propulsion system for ships that improves propulsion efficiency, reduces cavitation corrosion, and is easy to maintain.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] The ship's multi-stage propeller propulsion system includes a fixed shaft, on which a lead propeller, an intermediate-pressure propeller, and a tail propeller are sequentially mounted. Each of the lead propeller, intermediate-pressure propeller, and tail propeller has blades and a mounting housing. A hub motor is provided between the mounting housing and the fixed shaft. The hub motor includes a rotating housing, which is fixedly connected to the mounting housing and rotatably connected to the fixed shaft.

[0007] The fixed shaft includes a stepped shaft, and three stepped shafts are coaxially arranged, with the diameters of the three stepped shafts decreasing sequentially.

[0008] The blades of the medium-pressure propeller and the tail propeller are provided with an anti-cavitation coating, the thickness of which is 50-200μm.

[0009] The pilot propeller is equipped with a flow guide in the middle.

[0010] The rotating housing has a fixed step at its end.

[0011] The rotating housing is located at both ends of the stepped shaft.

[0012] The blades and the mounting housing are an integral structure.

[0013] The technical advantages of this invention are as follows: The multi-stage propeller propulsion system for ships, employing three propellers as the ship's power propulsion system, enables multi-stage energy transfer. The three-stage propeller loading reduces the load on individual blades, significantly delaying cavitation generation and meeting various navigation conditions. The use of a hub motor for direct drive instead of gearbox transmission reduces structural complexity, decreases the axial length of the propulsion system, and facilitates disassembly and maintenance. Furthermore, the use of a lead propeller and the application of anti-cavitation coatings on the blades of the intermediate-pressure and stern propellers reduce the impact of cavitation corrosion. Attached Figure Description

[0014] This manual includes the following figures, which illustrate the following:

[0015] Figure 1 This is a structural schematic diagram of the ship multi-stage propeller propulsion system of this utility model;

[0016] Figure 2 yes Figure 1 Schematic diagram of section AA;

[0017] Figure 3 This is an installation diagram of the hub motor of this utility model.

[0018] The following are marked in the diagram: 1. Fixed shaft; 2. Lead propeller; 3. Medium-pressure propeller; 4. Tail propeller; 5. Blade; 6. Mounting housing; 7. Hub motor; 8. Rotating housing; 9. Stepped shaft; 10. Shield; 11. Fixed step; 12. Bearing; 13. Permanent magnet; 14. Electromagnetic coil. Detailed Implementation

[0019] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of this invention, and to facilitate its implementation.

[0020] like Figure 1 and Figure 2As shown, the ship's multi-stage propeller propulsion system includes a fixed shaft 1, on which a leader propeller 2, an intermediate-pressure propeller 3, and a tail propeller 4 are sequentially arranged. Each of the leader propeller 2, intermediate-pressure propeller 3, and tail propeller 4 is provided with blades 5 and a mounting housing 6. A hub motor 7 is provided between the mounting housing 6 and the fixed shaft 1. The hub motor 7 includes a rotating housing 8, which is fixedly connected to the mounting housing 6 and rotatably connected to the fixed shaft 1.

[0021] The lead propeller 2 is designed for high-speed operation, used to pre-accelerate the water flow and eliminate incoming turbulence. It is made of titanium alloy. While rotating, the lead propeller 2 disperses the wake of the intermediate-pressure propeller 3 towards the surface of the lead propeller 2 and behind the shroud 10, thereby reducing cavitation and improving propeller propulsion efficiency while reducing vibration and noise. The intermediate-pressure propeller 3 is designed for medium speed and medium load, bearing the main thrust, and is made of duplex stainless steel. The tail propeller 4 is designed for low speed and high torque, suppressing energy loss from the wake rotation, and is made of nickel-aluminum bronze. The diameter ratio of the three-stage blades 5 of the lead propeller 2, intermediate-pressure propeller 3, and tail propeller 4 is D1:D2:D3 = 1:1.6:2.2, and the spacing between each propeller stage is L1 = 0.8D1 and L2 = 1.2D2, determined through CFD simulation to ensure that the tail-stage blade 5 is in the stable acceleration zone of the front-stage wake.

[0022] like Figure 2 As shown, the fixed shaft 1 includes three stepped shafts 9, which are coaxially arranged, with their diameters decreasing sequentially. The three stepped shafts 9 are arranged in ascending order of diameter, meaning the tail propeller 4, intermediate-pressure propeller 3, and leader propeller 2 are respectively mounted on the largest, medium, and smallest diameter stepped shafts 9. When the leader propeller 2 or intermediate-pressure propeller 3 needs to be disassembled for maintenance, only the corresponding structure needs to be axially removed from the fixed shaft 1 without disassembling the entire propulsion system, thus facilitating maintenance. Furthermore, the three propellers are driven by independent hub motors 7, so damage to local parts will not affect the overall propulsion system.

[0023] The blades 5 of the medium-pressure propeller 3 and the tail propeller 4 are equipped with an anti-cavitation coating with a thickness of 50-200 μm. The anti-cavitation coating includes polyurethane and silicon carbide particles, forming an anti-cavitation protective layer for the blades 5, reducing the impact of cavitation corrosion on the structural performance of the blades 5, and reducing the impact effect of cavitation collapse; in addition, the motor cooling water circuit is linked with the ship's seawater circulation system to avoid local overheating that could cause cavitation.

[0024] like Figure 1 and Figure 2As shown, a shroud 10 is provided in the middle of the leader propeller 2. The shroud 10 serves to guide the flow, reduce water resistance, and improve propulsion efficiency. The blades 5 of the leader propeller 2 can be additionally designed with a serrated trailing edge to further reduce turbulence noise. If used as a propulsion system for port tugboats, fiber optic sensors can be pre-embedded at the root of the blades 5 to monitor stress cracks in real time. A rubber damping layer is installed on the inner wall of the shroud 10 to absorb cavitation collapse shock waves, achieving a better impact resistance design.

[0025] like Figure 3 As shown, a fixed step 11 is provided at the end of the rotating housing 8. The fixed step 11 serves to position and limit the axial movement of the rotating housing 8.

[0026] like Figure 2 As shown, the rotating housing 8 is located at both ends of the stepped shaft 9. Due to the axial distance between the housing 6 and the rotating housing 6, two hub motors 7 are installed at both ends of each stepped shaft 9 to synchronously drive the propeller, forming multi-point support and improving the reliability of the propeller operation.

[0027] like Figure 1 As shown, the blade 5 and the mounting housing 6 are an integral structure. The rotating housing 8 is cast integrally with the blade 5, which reduces the use of connecting parts and reduces the complexity of installation.

[0028] like Figure 2 and Figure 3 As shown, a bearing 12 is provided between the rotating housing 8 and the fixed shaft 1. The inner and outer rings of the bearing 12 fix the rotating housing 8 and the fixed shaft 1 respectively, so that the rotating housing 8 rotates around the axis of the fixed shaft 1 to drive the propeller. The hub motor 7 is located inside the mounting housing 6, which improves the sealing performance.

[0029] Each propeller stage is equipped with an independent hub motor 7 for independent drive. The rotating housing 8 contains a permanent magnet 13 and an electromagnetic coil 14, making it suitable for cargo ships, tugboats, marine engineering vessels, and other applications requiring high thrust efficiency and anti-cavitation performance. Based on the ship's draft sensor and speed feedback, it automatically switches between "shallow water mode" and "deep water mode". In shallow water mode, only the lead propeller 2 and the medium-pressure propeller 3 provide propulsion, while in deep water mode, all three propellers are used for full-power propulsion.

[0030] After technical effectiveness verification, the test items were compared between a traditional single propeller and the three-stage propeller of this application. The test data are as follows:

[0031] index Traditional single-stage propeller This application involves a three-stage propeller. Propulsion efficiency 35kn speed 58％ 76％ Cavitation noise 150rpm 142dB 118dB Emergency braking distance 1.2km 0.7km

[0032] Table: Comparison of Measured Performance

[0033] Example 1: Used as the main propulsion system for ocean-going cargo ships, with the following parameters: lead propeller 2 diameter 1.2m, intermediate-pressure propeller 3 diameter 1.92m, stern propeller 4 diameter 2.64m; motor power: lead propeller 2800kW, intermediate-pressure propeller 31200kW, stern propeller 42000kW; mode switching logic: when the draft is <10m, stern propeller 4 is disabled to avoid shallow water effect; when the speed is >18 knots, three-stage phase synchronization control is activated to suppress vibration and noise.

[0034] Compared with conventional propulsion systems, it offers several advantages: cavitation suppression: the critical velocity for cavitation initiation is increased by 22% at the same speed; efficiency improvement: propulsion efficiency is increased by 15%-20% compared to traditional single propellers, with significant advantages, especially under partial load conditions; and control redundancy: it can maintain 60% thrust in the event of a single-stage failure and achieve emergency steering through differential control.

[0035] This multi-stage propeller propulsion system enables multi-stage energy transfer by using three propellers as the ship's power propulsion system. The three-stage propellers reduce the load on individual blades 5, significantly delaying cavitation generation and meeting various navigation conditions. The hub motor 7 directly drives the propulsion system instead of a gearbox, reducing structural complexity, decreasing the axial length of the propulsion system, and facilitating disassembly and maintenance. Furthermore, the use of the lead propeller 2 and the anti-cavitation coating applied to the blades 5 of the intermediate-pressure propeller 3 and the stern propeller 4 reduce the impact of cavitation corrosion.

[0036] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A multi-stage propeller propulsion system for ships, characterized in that: The device includes a fixed shaft (1), on which a leading propeller (2), a medium-pressure propeller (3) and a tail propeller (4) are arranged in sequence. Each of the leading propeller (2), the medium-pressure propeller (3) and the tail propeller (4) is provided with blades (5) and a mounting housing (6). A hub motor (7) is provided between the mounting housing (6) and the fixed shaft (1). The hub motor (7) includes a rotating housing (8), which is fixedly connected to the mounting housing (6) and rotatably connected to the fixed shaft (1).

2. The multi-stage propeller propulsion system for ships according to claim 1, characterized in that: The fixed shaft (1) includes a stepped shaft (9), and three stepped shafts (9) are coaxially arranged, with the diameters of the three stepped shafts (9) decreasing sequentially.

3. The multi-stage propeller propulsion system for ships according to claim 1 or 2, characterized in that: The blades (5) of the medium-pressure propeller (3) and the tail propeller (4) are provided with an anti-cavitation coating, the thickness of which is 50-200μm.

4. The multi-stage propeller propulsion system for ships according to claim 3, characterized in that: The pilot propeller (2) is provided with a flow guide (10) in the middle.

5. The multi-stage propeller propulsion system for ships according to claim 4, characterized in that: The rotating housing (8) has a fixed step (11) at its end.

6. The multi-stage propeller propulsion system for ships according to claim 2, characterized in that: The rotating housing (8) is located at both ends of the stepped shaft (9).

7. The multi-stage propeller propulsion system for ships according to claim 1, characterized in that: The blade (5) and the mounting housing (6) are an integral structure.

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