Ship propulsion shafting and design method thereof

Abstract

The invention provides a ship propulsion shafting and a design method thereof, and the design method comprises the steps: determining positioning points at two ends of a shafting bow and a shafting stern according to the overall arrangement of a ship; determining the shaft diameter and length of each shaft section of the shafting according to the propulsive power requirement and the positioning points at the bow and stern ends of the shafting; determining the positions and the number of the bearings; when all shafts are calculated to be metal shafts, shafting strength and shafting pilot test calculation are carried out, and when the intermediate shaft is replaced by a carbon fiber shaft from a metal shaft and other shaft sections are not changed, shafting strength and shafting pilot test calculation is carried out; and when the strength and the shafting alignment of the shafting after the carbon fiber shaft is replaced meet the set requirements, the current shafting design scheme is reasonable. According to the design method, a replaceable intermediate shaft can be arranged on the propulsion shafting, and specific parameters of each shafting are reasonably determined, so that the design requirements of ships under certain special conditions are met, and the design method is suitable for shafting design of kiloton-level surface ships propelled by adopting conventional power shafting belt propellers.

Description

Technical Field

[0001] This invention relates to the field of ship design technology, and in particular to a ship propulsion shafting system and its design method. Background Technology

[0002] Ship design is a complex systems engineering project, requiring not only breakthroughs in numerous individual advanced technologies but also overall integration. The propeller-shaft system is one of the significant factors influencing ship vibration and noise. A series-connected carbon fiber intermediate shaft can reduce ship vibration and noise to a certain extent, representing a noise reduction measure in the acoustic design and control technology of propeller-shaft coupled systems.

[0003] Therefore, it is essential to connect carbon fiber shafts in series with traditional steel shaft systems. However, there is currently no comprehensive design method for propulsion shaft systems with connected carbon fiber shafts. Summary of the Invention

[0004] The main objective of this invention is to provide a ship propulsion shafting system and its design method, which aims to facilitate the design of intermediate shafts made of carbon fiber in ship propulsion shafting systems.

[0005] To achieve the above objectives, the present invention provides a design method for a ship propulsion shafting system, comprising the following steps: Based on the overall ship layout, determine the propeller center position and the thrust bearing output flange center position to determine the positioning points at both ends of the shafting bow and stern. Based on the propulsion power requirements and the positioning points at both ends of the shaft system (bow and stern), determine the shaft diameter and length of each shaft segment. The position and number of each bearing are determined based on the shaft diameter and length of each shaft segment in the shaft system. When all shafts are metal shafts, perform strength and alignment calculations for the shaft system. When the intermediate shaft is replaced with a carbon fiber shaft while the other shaft segments remain unchanged, perform strength and alignment calculations for the shaft system. If the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements, it indicates that the current shaft system design is reasonable. If the strength and alignment of the shaft system after replacing the carbon fiber shaft do not meet the set requirements, return to the step of determining the shaft diameter and length of each shaft segment based on the propulsion power requirements and the positioning points at the bow and stern ends of the shaft system, and then redetermine the shaft diameter and length of each shaft segment as well as the position and number of each bearing, until the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements.

[0006] Preferably, when determining the shaft diameter and length of each shaft segment of the shaft system, the propeller shaft and tail shaft are respectively arranged at the tail and middle of the shaft system, and the intermediate shaft, which can be replaced with a carbon fiber shaft, is located at the front of the shaft system.

[0007] Preferably, the intermediate shaft, which can be replaced with a carbon fiber shaft, is located inside the hull.

[0008] Preferably, when the intermediate shaft is a carbon fiber shaft, the intermediate shaft is composed of steel segments, carbon fiber segments and steel segments connected in sequence, and the steel segments and carbon fiber segments are fixedly connected by mechanical connection or adhesive.

[0009] Preferably, when determining the shaft diameter and length of each shaft segment of the shaft system, the intermediate shaft satisfies the following condition: 1) When the intermediate shaft is a carbon fiber shaft, its ability to transmit ship thrust, pull and torque to the propulsion shaft system is no less than the corresponding indicators when the intermediate shaft is a metal shaft; 2) The basic shaft diameter and shape of the intermediate shaft of the carbon fiber shaft are consistent with those of the metal shaft section; 3) The inner diameter of the carbon fiber shaft shall not be less than the inner diameter of the intermediate shaft of the interchangeable metal shaft section.

[0010] Preferably, when determining the shaft diameter and length of each shaft segment in the shaft system, the weight of each shaft system satisfies the following relationship: α = weight when the intermediate shaft is a metal shaft segment ÷ total weight of all metal shaft segments in the entire shaft system, including the intermediate shaft segment, α≤0.13; β = (Weight when the intermediate shaft is a metal section - Weight when the intermediate shaft is a carbon fiber section) ÷ Weight when the intermediate shaft is a metal section, β ≤ 0.5; γ = length of intermediate shaft ÷ total length of all shaft segments in the shaft system, γ ≤ 0.12.

[0011] Preferably, in the step of determining the position and number of each bearing based on the determined shaft diameter and length of each shaft segment of the shaft system, the load of each bearing is positive, and the bearing load should not be less than 20% of the total weight between two adjacent spans.

[0012] Preferably, in the step of determining the position and number of each bearing based on the determined shaft diameter and length of each shaft segment of the shaft system, no support bearing is provided along the entire length of the interchangeable intermediate shaft; when a gearbox is provided, the load difference between the front and rear bearings of the gearbox should not exceed 20% of the sum of the weight of the shaft segment between the two bearings and the weight of the large gear in the gearbox.

[0013] Preferably, when the intermediate shaft, which can be replaced with a carbon fiber shaft, is inserted into the watertight bulkhead, a compartment sealing device is provided at the interface between the intermediate shaft and the bulkhead, and a metal protective ring of the same material as the shaft is fitted on the outside of the interface between the carbon fiber shaft and the compartment sealing device, and the metal protective ring is fastened to the carbon fiber shaft.

[0014] The present invention also proposes a ship propulsion shafting system, which is manufactured using the above-mentioned ship propulsion shafting design method.

[0015] The design method for ship propulsion shafting proposed in this invention has the following beneficial effects: 1. This design method can realize the setting of a replaceable intermediate shaft in the propulsion shaft system and reasonably determine the specific parameters of each shaft system, thereby meeting the design requirements of ships under certain special conditions. It is applicable to the shaft system design of thousand-ton surface ships with conventional power shaft system and propeller propulsion. 2. When designing a ship, this design method is used to design the propulsion shaft system. This allows the intermediate shaft of the propulsion shaft system to be replaced without the ship entering dry dock, while the propulsion shaft system also meets the corresponding design strength requirements. Attached Figure Description

[0016] Figure 1 This is a side view of the propeller shaft system in the design method of the ship propulsion shaft system of the present invention. Figure 2 This is a top view of the propeller shaft system in the design method of the ship propulsion shaft system of the present invention; Figure 3 This is a cross-sectional structural schematic diagram of the propeller shaft system in the design method of the ship propulsion shaft system of the present invention; Figure 4 This is a flowchart illustrating the design method of the ship propulsion shafting system of the present invention.

[0017] In the diagram, 1-propeller, 2-propeller shaft, 3-tail shaft, 4-intermediate shaft of carbon fiber shaft, 5-intermediate shaft of metal shaft, 6-forward tail shaft bracket bearing, 7-tail shaft tube bearing, 8-intermediate bearing, 9-thrust bearing, 10-sleeve hydraulic coupling, 11-flange hydraulic coupling, 12-compartment sealing device, 13-tail shaft sealing device, 14-tail shaft bracket bearing, 15-tail shaft bracket, 16-forward tail shaft bracket, 17-watertight bulkhead.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] It should be noted that in the description of this invention, the terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] This invention proposes a design method for ship propulsion shafting.

[0022] Reference Figures 1 to 4 In this preferred embodiment, a method for designing a ship propulsion shafting system includes the following steps: Step S10: Based on the overall ship layout, determine the position of the propeller core of propeller 1 and the center position of the thrust bearing output flange to determine the positioning points at both ends of the shafting bow and stern. Step S20: Determine the shaft diameter and length of each shaft segment of the shaft system based on the propulsion power requirements and the positioning points at both ends of the shaft system (bow and stern). Step S30: Determine the position and quantity of each bearing based on the determined shaft diameter and length of each shaft segment in the shaft system; Step S40: When all shafts are metal shafts, perform strength and alignment calculations of the shaft system (specifically, substitute each parameter into existing technology or software for calculation to obtain strength and other parameters). When the intermediate shaft is replaced with a carbon fiber shaft while the other shaft segments remain unchanged, perform strength and alignment calculations of the shaft system. If the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements, it indicates that the current shaft system design is reasonable, and step S50 is executed. Step S50: Based on the determined parameters, gradually refine the relevant design work (thereby providing technical support for the final implementation in engineering practice). If the strength and alignment of the shaft system after replacing the carbon fiber shaft do not meet the set requirements, then return to step S20 until the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements.

[0023] During the design process, to determine whether the current scheme meets the design requirements, it is necessary to perform calculations in the computational model for both the metal and carbon fiber intermediate shaft models to obtain their strength and shaft alignment. The calculated data from both models are then compared. Only if the comparison shows that the data meets the set requirements is the current design scheme considered reasonable. By comparing and analyzing test data before and after the implementation of control measures, or with results from using ordinary shaft components, the noise reduction effect after changing the intermediate shaft material is verified. This supports the verification and implementation improvement of the acoustic design and control technology for propeller-shaft coupling systems.

[0024] Specifically, in step S20, when determining the shaft diameter and length of each shaft segment of the shaft system, the propeller shaft 2 and the tail shaft 3 are respectively arranged at the tail and middle of the shaft system, and the intermediate shaft, which can be replaced with a carbon fiber shaft, is located at the front of the shaft system.

[0025] The propulsion shafting system consists of three to four shaft segments from stern to bow: propeller shaft 2, stern shaft 3, and intermediate shaft (if the shafting system includes four shaft segments, the intermediate shaft is divided into a first intermediate shaft and a second intermediate shaft). The stern end of propeller shaft 2 is connected to the ship's propeller 1, and the bow end of propeller shaft 2 is connected to the stern end of stern shaft 3 via a hydraulic coupling. The front end of stern shaft 3 passes through the stern tube and stern seal device 13, and a hydraulic coupling is installed at its front, connecting it to a partial steel structure at the stern end of the carbon fiber shaft segment. The overall layout of the shafting system is as follows: propeller shaft 2 and stern shaft 3 are respectively located at the stern and middle of the shafting system, while the carbon fiber shaft is located at the front of the shafting system. Under normal circumstances, after the ship is launched, the propeller shaft 2 is completely submerged below the waterline, and the stern shaft 3 is located in the middle and rear of the shafting system. The portion of the stern shaft 3 passing through the stern shaft sealing device 13 via the stern shaft 3 tube assembly is located inside the hull, while the portion of the stern shaft sealing device 13 facing the stern is completely submerged in water. The intermediate shaft, which can be replaced with a carbon fiber shaft, is located inside the hull. This design allows for convenient replacement of the metal shaft intermediate shaft with a carbon fiber shaft from inside the hull in certain special circumstances, without the ship being in dry dock.

[0026] Regarding the selection of the placement of interchangeable shaft segments in the shafting system, since propulsion shafting systems are typically composed of several shaft segments connected end-to-end, the shaft segments located at the stern are usually fully or partially submerged below the waterline. Under non-dock conditions, this design method is not applicable to the interchangeability of shaft segments that are fully or partially submerged. In this shafting design method, to achieve non-dock interchangeability, the intermediate shaft should be located inside the hull. Therefore, this shafting design method requires, in principle, that carbon fiber shafts interchangeable with metal shafts without docking be entirely located inside the hull. Furthermore, since the interchange work is carried out manually, the operating area should be located in a mechanical space with ventilation and lighting. This area should have a dedicated storage rack for interchangeable shaft segments (equipped with locking mechanisms to ensure reliable fixation under various navigation conditions), and should also consider sufficient space for manual lifting and interchange operations.

[0027] Specifically, in this design method, to reduce the impact of changing intermediate shafts of different materials on the shaft system, design requirements are proposed for the shaft length and diameter range of the non-metallic shaft segments (such as carbon fiber shafts) connected in series in the shaft system. In step S20, when determining the shaft diameter and length of each shaft segment in the shaft system, the intermediate shaft must meet the following conditions: 1) When the intermediate shaft is a carbon fiber shaft, its ability to transmit ship thrust, pull and torque to the propulsion shaft system is no less than the corresponding indicators when the intermediate shaft is a metal shaft; 2) The basic shaft diameter and shape of the intermediate shaft of the carbon fiber shaft are consistent with those of the metal shaft section; 3) The inner diameter of the carbon fiber shaft shall not be less than the inner diameter of the intermediate shaft of the interchangeable metal shaft section.

[0028] 4) When the intermediate shaft is a carbon fiber shaft, the connection between the carbon fiber shaft and the front and rear end connection interfaces is made of flange (of course, a cylindrical interface can also be used). The flange material is the same as that of the steel shaft, and it should be ensured that the interface shape and number in the connection elements are consistent, so as to achieve interchangeability with metal shaft sections of the same length. Generally, for all-metal shaft systems, the length and diameter of the metal section in the intermediate shaft at the front of the system only need to meet the relevant industry standards. Without affecting interchangeability with steel shafts, the carbon fiber shaft can retain the structure and form of the joint between the carbon fiber material and the steel, both locally and internally.

[0029] In this embodiment, when the intermediate shaft is a carbon fiber shaft, it consists of sequentially connected steel segments, carbon fiber segments, and steel segments, with the steel and carbon fiber segments fixed together by mechanical connection or bonding. The connection to the front and rear shaft segments on the shaft system can be via flanges or reamed bolts. Alternatively, a non-flange connection (e.g., via a sleeve hydraulic coupling) can be used.

[0030] In step S20, when determining the shaft diameter and length of each shaft segment in the shaft system, the weight control of interchangeable shaft segments and the allocation of each weight ratio are used. These are expressed using the following three dimensionless constants α, β, and γ, respectively, and the weights of each shaft system satisfy the following relationship: α = weight when the intermediate shaft is a metal shaft segment ÷ total weight of all metal shaft segments in the entire shaft system, including the intermediate shaft segment (excluding the weight of shaft system accessories), α≤0.13; β = (Weight when the intermediate shaft is a metal section - Weight when the intermediate shaft is a carbon fiber section) ÷ Weight when the intermediate shaft is a metal section, β ≤ 0.5; γ = length of intermediate shaft ÷ total length of all shaft segments in the shaft system, γ ≤ 0.12.

[0031] By adopting the above relationship, the replaceability of the intermediate shaft can be guaranteed, ensuring that its design specifications meet the predetermined requirements.

[0032] Furthermore, in step S30, where the position and number of each bearing are determined based on the determined shaft diameter and length of each shaft segment of the shaft system, the load on each bearing is a positive value, and the bearing load should not be less than 20% of the total weight between two adjacent spans. The bearing load generally does not exceed the specified value.

[0033] In this design method, the arrangement of shaft support bearings should, in addition to meeting the requirements of relevant national or industry specifications and standards, also meet the following conditions: no support bearings are installed along the entire length of the interchangeable intermediate shaft. That is, considering the mass distribution of each section of the shaft system, and without arranging support points along the entire length of the replaceable shaft section, the replaceable shaft section, regardless of its material, must meet the normal operating conditions of the propulsion shaft system. When a gearbox is included, the load difference between the front and rear bearings of the gearbox should not exceed 20% of the sum of the weight of the shaft section between the two bearings and the weight of the large gear (gearbox) in the gearbox.

[0034] Furthermore, referring to Figure 3 When the intermediate shaft, which can be replaced with a carbon fiber shaft, is installed in the watertight bulkhead 17, a bulkhead sealing device is provided at the interface between the intermediate shaft and the bulkhead to ensure the sealing requirements between the intermediate shaft and the watertight bulkhead 17. Additionally, a metal protective ring (thickness greater than 6mm) of the same material as the shaft system (referring to the tail shaft 3 and propeller shaft 2) is fitted around the interface between the carbon fiber shaft and the bulkhead sealing device. The metal protective ring is tightly connected to the carbon fiber shaft (the two are tightly connected through an interference fit). Because carbon fiber is not wear-resistant, the metal protective ring serves two purposes: firstly, it prevents the carbon fiber material from being worn, ensuring long-term reliable use; secondly, it ensures that the metal protective ring and the carbon fiber shaft can rotate synchronously.

[0035] This design method can further support the testing and verification of vibration control technology for ship propeller shaft systems by conducting prototype design, manufacturing, and actual ship performance testing.

[0036] The ship propulsion shafting design method proposed in this embodiment has the following beneficial effects: 1. This design method can realize the setting of a replaceable intermediate shaft in the propulsion shaft system and reasonably determine the specific parameters of each shaft system, thereby meeting the design requirements of ships under certain special conditions. It is applicable to the shaft system design of surface ships of 1,000 tons with conventional power shaft system and propeller propulsion type. 2. When designing a ship, this design method is used to design the propulsion shaft system. This allows the intermediate shaft of the propulsion shaft system to be replaced without the ship entering dry dock, while the propulsion shaft system also meets the corresponding design strength requirements.

[0037] The present invention also proposes a ship propulsion shafting system.

[0038] The ship propulsion shafting system proposed in this preferred embodiment is manufactured using the ship propulsion shafting design method described above. The specific steps of the ship propulsion shafting design method are the same as those described in the above embodiment and will not be repeated here.

[0039] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A design method for a ship propulsion shafting system, characterized in that, Includes the following steps: Based on the overall ship layout, determine the propeller center position and the thrust bearing output flange center position to determine the positioning points at both ends of the shafting bow and stern. Based on the propulsion power requirements and the positioning points at both ends of the shaft system (bow and stern), determine the shaft diameter and length of each shaft segment. The position and number of each bearing are determined based on the shaft diameter and length of each shaft segment in the shaft system. When all shafts are metal shafts, perform strength and alignment calculations for the shaft system. When the intermediate shaft is replaced with a carbon fiber shaft while the other shaft segments remain unchanged, perform strength and alignment calculations for the shaft system. If the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements, it indicates that the current shaft system design is reasonable. If the strength and alignment of the shaft system after replacing the carbon fiber shaft do not meet the set requirements, return to the step of determining the shaft diameter and length of each shaft segment based on the propulsion power requirements and the positioning points at the bow and stern ends of the shaft system, and then redetermine the shaft diameter and length of each shaft segment as well as the position and number of each bearing, until the strength and alignment of the shaft system after replacing the carbon fiber shaft meet the set requirements.

2. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, When determining the shaft diameter and length of each shaft segment of the shaft system, the propeller shaft and tail shaft are respectively arranged at the tail and middle of the shaft system, and the intermediate shaft, which can be replaced with a carbon fiber shaft, is located at the front of the shaft system.

3. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, The design allows for the replacement of the intermediate shaft with a carbon fiber shaft, which is located inside the hull.

4. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, When the intermediate shaft is a carbon fiber shaft, the intermediate shaft is made of steel segments, carbon fiber segments and steel segments connected in sequence, and the steel segments and carbon fiber segments are fixedly connected by mechanical connection or adhesive.

5. The design method for a ship propulsion shafting system as described in claim 2, characterized in that, When determining the shaft diameter and length of each shaft segment in the shaft system, the intermediate shaft must satisfy the following condition: 1) When the intermediate shaft is a carbon fiber shaft, its ability to transmit ship thrust, pull and torque to the propulsion shaft system is no less than the corresponding indicators when the intermediate shaft is a metal shaft; 2) The basic shaft diameter and shape of the intermediate shaft of the carbon fiber shaft are consistent with those of the metal shaft section; 3) The inner diameter of the carbon fiber shaft shall not be less than the inner diameter of the intermediate shaft of the interchangeable metal shaft section.

6. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, When determining the shaft diameter and length of each shaft segment in the shaft system, the weight of each shaft in the system satisfies the following relationship: α = weight when the intermediate shaft is a metal shaft segment ÷ total weight of all metal shaft segments in the entire shaft system, including the intermediate shaft segment, α≤0.13; β = (Weight when the intermediate shaft is a metal section - Weight when the intermediate shaft is a carbon fiber section) ÷ Weight when the intermediate shaft is a metal section, β ≤ 0.5; γ = length of intermediate shaft ÷ total length of all shaft segments in the shaft system, γ ≤ 0.

12.

7. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, In the step of determining the position and number of each bearing based on the determined shaft diameter and length of each shaft segment of the shaft system, the load of each bearing is positive, and the bearing load should not be less than 20% of the total weight between two adjacent spans.

8. The design method for a ship propulsion shafting system as described in claim 1, characterized in that, In the step of determining the position and number of each bearing based on the determined shaft diameter and length of each shaft segment of the shaft system, no support bearing is set along the entire length of the interchangeable intermediate shaft; when a gearbox is provided, the load difference between the front and rear bearings of the gearbox should not exceed 20% of the sum of the weight of the shaft segment between the two bearings and the weight of the large gear in the gearbox.

9. The design method for a ship propulsion shafting system as described in any one of claims 1 to 8, characterized in that, When the intermediate shaft, which can be replaced with a carbon fiber shaft, is installed in the watertight bulkhead, a compartment sealing device is provided at the interface between the intermediate shaft and the bulkhead. A metal protective ring of the same material as the shaft is fitted on the outside of the interface between the carbon fiber shaft and the compartment sealing device, and the metal protective ring is tightly connected to the carbon fiber shaft.

10. A ship propulsion shafting system, characterized in that, It is manufactured using the design method of the ship propulsion shafting as described in any one of claims 1 to 9.

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