Shaft support for twin-propeller ship
By setting a saw tooth structure on the trailing edge of the shaft bracket, the flow separation and vibration problems are solved, and the propulsion efficiency of the propeller and the durability of the bracket are improved.
Patent Information
- Application Number
- CN202510507552.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2025-07-22
AI Technical Summary
The existing fixed propeller shaft brackets are prone to form strong flow separation vortex in the water flow, resulting in cavitation and structural vibration, affecting the propeller efficiency and support life.
A periodically changing sawtooth structure is provided at the trailing edge of the shaft bracket, and the sawtooth unit includes a protrusion and a recess, designed in a curved or flexural shape to reduce flow separation and noise.
The large separation vortex is broken through the sawtooth structure to reduce the risk of cavitation, improve wake flow, improve propulsion efficiency and extend the life of the bracket.
Smart Images
Figure CN120348448A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of propeller shaft brackets, and particularly to a shaft bracket for a twin-screw ship. Background Art
[0002] Passenger ships adopt a design style of shallow draft, high speed, and twin-screw propulsion based on functional requirements and safety considerations. Two symmetrical propellers are distributed on both sides of the hull. The slender hull tail line characteristics are not conducive to arranging a large fin to support the propeller. See Figure 13 ., To solve the problem of fixing the propeller shaft, a bracket form is often used. In addition to bearing structural loads, the propeller shaft bracket also bears large hydrodynamic loads in the water flow. Especially for the bracket near the propeller, its dynamic fluid load is large, and flow separation is likely to occur in the back pressure area of the bracket, causing the bracket to be subjected to large pulsating vortex-induced forces, which are likely to lead to cavitation and structural vibration. When the cavitation of the shaft bracket is serious, it can cause erosion and damage to the bracket structure, threatening the safety of the hull.
[0003] The above-mentioned existing brackets for fixing the propeller shaft have the following defects:
[0004] The shaft bracket adopts a straight trailing edge form. See Figure 17 ., When the bracket encounters water flow with a large angle of attack, relatively strong flow separation will form near its trailing edge, forming a large separation vortex. This separation vortex will cause strong pulsating water loads on the bracket, and cavitation is likely to form in the wake area of the bracket, causing erosion to the bracket. In addition, this unstable vortex will also have an adverse impact on the propeller, reducing the propeller efficiency.
[0005] Therefore, to solve the above problems, the present invention proposes a shaft bracket for a twin-screw ship that can optimize the fluid performance of the shaft bracket and control the flow separation on its surface. Summary of the Invention
[0006] To solve the problems existing in the above-mentioned existing propeller shaft brackets, the present invention provides a shaft bracket for a twin-screw ship.
[0007] According to an object of the present invention, the present invention provides a shaft bracket for a twin-screw ship. On both sides of the hull tail in the width direction, a stern shaft is respectively arranged. A propeller is arranged at the end of the stern shaft. The stern shaft and the hull are supported and connected by a bracket.
[0008] A sawtooth structure is provided on the trailing edge of the bracket. The shape of the sawtooth structure is a curve or a broken line with periodic changes. The sawtooth structure includes a number of sawtooth units arranged in sequence along the length direction of the trailing edge of the bracket. The adjacent sawtooth units have the same shape and size. Each sawtooth unit includes a protrusion and a recess. Both the protrusion and the recess extend along the length direction of the bracket. The shapes of the protrusion and the recess are curves or broken lines.
[0009] Preferably, in the length direction of the bracket, the protrusion and the recess are respectively located on both sides of the trailing edge of the bracket.
[0010] Preferably, in the length direction of the bracket, the maximum distance between the protrusion and the trailing edge of the bracket is equal to the maximum distance between the recess and the trailing edge of the bracket.
[0011] In the length direction of the trailing edge of the bracket, the distance between the tops of adjacent protrusions and the distance between the bottoms of adjacent recesses are both equal.
[0012] Preferably, the sawtooth structure is an outgrowth type. In the length direction of the bracket, both the protrusion and the recess are located on the same side of the trailing edge of the bracket.
[0013] Preferably, the shapes of both the protrusion and the recess are curves, and the shape of the sawtooth structure is a sine curve.
[0014] Preferably, both the protrusion and the recess are broken lines, and the shapes of the protrusion and the recess are isosceles triangles.
[0015] Preferably, in the length direction of the bracket, the proportion of the length of the sawtooth structure to the total length of the bracket ranges from 10% to 100%.
[0016] In the length direction of the trailing edge of the bracket, the distance between the tops of adjacent protrusions ranges from 100 to 800 mm. In the length direction of the bracket, the distance between the top of an adjacent protrusion and the bottom of a recess ranges from 40 to 400 mm.
[0017] Preferably, the bracket is a plate-like structure. The dimension of the bracket in the width direction of the hull is much smaller than the dimension of the bracket in the length direction of the hull.
[0018] The sides of the bracket in the width direction of the hull are all arc-shaped, and the dimension of the bracket in the width direction of the hull gradually decreases in a way that is closer to both ends in the length direction of the hull.
[0019] Preferably, the size of the sawtooth structure in the hull width direction gradually decreases towards the end in the hull length direction, and the side surface of the sawtooth structure in the hull width direction and the side surface of the bracket in the hull width direction are continuously arranged.
[0020] Preferably, the bracket includes a front support part and a rear support part. The front support part and the rear support part are sequentially arranged at intervals on the stern shaft in a manner close to the propeller. The sawtooth structure is provided on both the front support part and the rear support part. Both the front support part and the rear support part are plate-like structures. The number of the front support parts is one, and the number of the rear support parts is two. In the circumferential direction of the stern shaft, the front support part and the rear support part are arranged in a staggered manner.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] For the shaft bracket for a twin-screw ship, by providing a sawtooth structure on the trailing edge of the bracket, the sawtooth structure has the functions of reducing flow separation and reducing vibration, noise and cavitation. By designing the sawtooth structure, the large separation vortex at the trailing edge of the ship bracket can be broken into multiple small separation vortices, suppressing flow separation, reducing the risk of cavitation occurrence, improving the hull wake at the same time, enhancing the propeller inflow quality, and thus improving the propeller propulsion efficiency.
[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Description of the Drawings
[0024] Figure 1 is an overall schematic diagram of a shaft bracket for a twin-screw ship according to the present invention;
[0025] Figure 2 is a schematic connection diagram of the bracket and the stern shaft of a shaft bracket for a twin-screw ship according to the present invention;
[0026] Figure 3 is a schematic diagram of an embodiment of a sine-shaped sawtooth structure of a shaft bracket for a twin-screw ship according to the present invention;
[0027] Figure 4 is a schematic diagram of a second embodiment of a sine-shaped sawtooth structure of a shaft bracket for a twin-screw ship according to the present invention;
[0028] Figure 5 is a schematic diagram of a third embodiment of a sine-shaped sawtooth structure of a shaft bracket for a twin-screw ship according to the present invention;
[0029] Figure 6 is a schematic diagram of a fourth embodiment of a sine-shaped sawtooth structure of a shaft bracket for a twin-screw ship according to the present invention;
[0030] Figure 7Schematic diagram of the fifth embodiment of the sine-form sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0031] Figure 8 Schematic diagram of the first embodiment of the broken-line-form sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0032] Figure 9 Schematic diagram of the second embodiment of the broken-line-form sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0033] Figure 10 Schematic diagram of the third embodiment of the broken-line-form sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0034] Figure 11 Schematic diagram of the fourth embodiment of the broken-line-form sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0035] Figure 12 Schematic diagram of the embodiment in which the ratio of the length of the sawtooth structure of the shaft bracket for a twin-propeller ship to the total length of the bracket is less than 100%;
[0036] Figure 13 Schematic diagram of one perspective of the extended sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0037] Figure 14 Schematic diagram of another perspective of the extended sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0038] Figure 15 Schematic diagram of the cross-section of the extended sawtooth structure of the shaft bracket for a twin-propeller ship according to the present invention;
[0039] Figure 16 Schematic diagram of the flow characteristics of the sawtooth-shaped trailing edge of the shaft bracket for a twin-propeller ship according to the present invention;
[0040] Figure 17 Schematic diagram of a conventional twin-propeller passenger ship and its shaft bracket. Detailed implementation mode
[0041] The following description is for explaining the present invention in detail so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and other obvious variations can be thought of by those skilled in the art. The basic principles defined in the following description of the present invention can be applied to other implementation schemes, variant schemes, improvement schemes, equivalent schemes, and other technical schemes that do not depart from the spirit and scope of the present invention.
[0042] Please refer to Figure 1-2, the present invention provides a technical solution: a shaft bracket for a twin-screw ship. On both sides of the tail of the hull 100 in the width direction, a stern shaft 200 is respectively provided. A propeller is arranged at the end of the stern shaft 200. The stern shaft 200 and the hull 100 are supported and connected by a bracket 300;
[0043] A serrated structure 301 is arranged on the trailing edge of the bracket 300. The shape of the serrated structure 301 is a curve or a broken line with periodic changes. The serrated structure 301 includes a plurality of serration units 3011 arranged in sequence along the length direction of the trailing edge of the bracket 300. The adjacent serration units 3011 have the same shape and size. Each serration unit 3011 includes a protrusion 3011a and a recess 3011b. The protrusion 3011a and the recess 3011b are both formed by extending along the length of the bracket 300. The shapes of the protrusion 3011a and the recess 3011b are curves or broken lines.
[0044] By arranging the serrated structure 301 on the trailing edge of the bracket 300, the serrated structure 301 has the functions of reducing flow separation and reducing vibration and noise. By designing the serrated structure 301, the large separation vortex at the trailing edge of the ship bracket 300 can be broken into multiple small separation vortices, suppressing flow separation, reducing the risk of cavitation, and at the same time improving the wake of the hull 100 and enhancing the inflow quality of the propeller, thereby improving the propeller propulsion efficiency.
[0045] It should be noted that the design concept of the serrated trailing edge was first inspired by the research on the flight dynamics of owl wings by scientific researchers and has been widely applied to the trailing edge of the outer casing of aeroengines. The principle of improving flow is as Figure 16 shown.
[0046] In one embodiment, in the length direction of the bracket 300, the protrusion 3011a and the recess 3011b are respectively located on both sides of the trailing edge of the bracket 300. Continuing to refer to Figure 2 , to ensure that each serration unit 3011 in the serrated structure 301 can evenly break the separation vortex. Further, in the length direction of the bracket 300, the maximum distance between the protrusion 3011a and the trailing edge of the bracket 300 is equal to the maximum distance between the recess 3011b and the trailing edge of the bracket 300;
[0047] In the length direction of the trailing edge of the bracket 300, the distance between the tops of adjacent protrusions 3011a and the distance between the bottoms of adjacent recesses 3011b are both equal.
[0048] In one embodiment, referring to Figure 3-7, the shapes of the convex part 3011a and the concave part 3011b are both curves, and the shape of the sawtooth structure 301 is a sine curve. In another embodiment, refer to Figure 8-11 , both the convex part 3011a and the concave part 3011b are broken lines, and the shapes of the convex part 3011a and the concave part 3011b are triangular. In other words, the sawtooth structure 301 is overall in a "Z" shape. Preferably, the shapes of both the convex part 3011a and the concave part 3011b are isosceles triangles.
[0049] In the length direction of the bracket 300, the proportion range of the length of the sawtooth structure 301 relative to the total length of the bracket 300 is: 10% - 100%. In one embodiment, refer to Figure 12 , the proportion of the length of the sawtooth structure 301 relative to the total length of the bracket 300 is less than 100%, and the sawtooth structure 301 is located in the middle of the trailing edge length direction of the bracket 300.
[0050] Preferably, in the length direction of the trailing edge of the bracket 300, the distance range between the tops of adjacent convex parts 3011a is 100 - 800 mm, and in the length direction of the bracket 300, the distance range between the top of adjacent convex parts 3011a and the bottom of the concave part 3011b is 40 - 400 mm.
[0051] Furthermore, in the length direction of the trailing edge of the bracket 300, the end of the sawtooth structure 301 is flush with the trailing edge of the bracket 300 to ensure a stable connection between the trailing edge of the bracket 300 and the sawtooth structure 301. Further, for the sawtooth units 3011 at both ends of the sawtooth structure 301 in the length direction of the trailing edge of the bracket 300, the convex part 3011a therein is connected to the trailing edge of the bracket 300. Even further, the lowest point of the convex part 3011a is connected to the trailing edge of the bracket 300.
[0052] Further, the bracket 300 is a plate-like structure. The dimension of the bracket 300 in the width direction of the hull 100 is much smaller than the dimension of the bracket 300 in the length direction of the hull 100, so as to avoid large resistance generated when the water flow in the length direction of the hull 100 contacts the bracket 300, reduce the wear of the support, and extend the service life of the bracket 300. Further still, the sides of the bracket 300 in the width direction of the hull 100 are all arc-shaped. The dimension of the bracket 300 in the width direction of the hull 100 gradually decreases in a manner close to both ends of the length direction of the hull 100. The dimension of the serrated structure 301 in the width direction of the hull 100 gradually decreases in a manner close to the end of the length direction of the hull 100. The sides of the serrated structure 301 in the width direction of the hull 100 and the sides of the bracket 300 in the width direction of the hull 100 are continuously arranged.
[0053] See Figure 1 , the bracket 300 includes a front support portion 300a and a rear support portion 300b. The front support portion 300a and the rear support portion 300b are sequentially arranged at intervals on the stern shaft 200 in a manner close to the propeller. The serrated structure 301 is provided on both the front support portion 300a and the rear support portion 300b. Both the front support portion 300a and the rear support portion 300b are plate-like structures. The number of the front support portions 300a is one, and the number of the rear support portions 300b is two. In the circumferential direction of the stern shaft 200, the front support portion 300a and the rear support portion 300b are arranged in a staggered manner.
[0054] In another embodiment, the serrated structure 301 is of an extended type. In the length direction of the bracket 300, both the protruding portion 3011a and the recessed portion 3011b are located on the same side of the trailing edge of the bracket 300.
[0055] In summary, by providing the serrated structure 301 on the trailing edge of the bracket 300, the serrated structure 301 has the functions of reducing flow separation and reducing vibration and noise. By designing the serrated structure 301, the large separation vortex at the trailing edge of the ship bracket 300 can be broken into multiple small separation vortices, suppressing flow separation, reducing the risk of cavitation, improving the wake of the hull 100, and improving the inflow quality of the propeller, thereby improving the propeller propulsion efficiency.
[0056] The above-described embodiments are only used to illustrate the technical ideas and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The scope of the patent adoption of the present invention cannot be limited only by this embodiment. That is, any equivalent changes or modifications made according to the spirit disclosed by the present invention still fall within the scope of the patent of the present invention.
Claims
1. An axle bracket for a twin-screw ship, wherein a stern shaft (200) is provided on each of the two sides in the width direction at the tail of the hull (100), and a propeller is provided at the end of the stern shaft (200), characterized in that The stern shaft (200) and the hull (100) are supported and connected by a bracket (300). A sawtooth structure (301) is provided on the trailing edge of the bracket (300). The shape of the sawtooth structure (301) is a curve or a broken line with periodic changes. The sawtooth structure (301) includes a number of sawtooth units (3011) arranged in sequence along the length direction of the trailing edge of the bracket (300). The adjacent sawtooth units (3011) have the same shape and size. Each sawtooth unit (3011) includes a protrusion (3011a) and a recess (3011b). The protrusion (3011a) and the recess (3011b) both extend along the length direction of the bracket (300). The shapes of the protrusion (3011a) and the recess (3011b) are curves or broken lines.
2. The shaft bracket for a twin-screw ship according to claim 1 above, characterized in that, In the length direction of the bracket (300), the protrusion (3011a) and the recess (3011b) are respectively located on both sides of the trailing edge of the bracket (300).
3. A shaft bracket for a twin-propeller ship according to claim 2 above, characterized in that, In the length direction of the bracket (300), the maximum distance between the protrusion (3011a) and the trailing edge of the bracket (300) is equal to the maximum distance between the recess (3011b) and the trailing edge of the bracket (300). In the length direction of the trailing edge of the bracket (300), the distance between the tops of adjacent protrusions (3011a) and the distance between the bottoms of adjacent recesses (3011b) are both equal.
4. A shaft bracket for a twin-screw ship according to claim 1 above, characterized in that, The sawtooth structure (301) is an outgrowth type. In the length direction of the bracket (300), the protrusion (3011a) and the recess (3011b) are both located on the same side of the trailing edge of the bracket (300).
5. A shaft bracket for a twin-screw ship according to claim 1 above, characterized in that, The shapes of the protrusion (3011a) and the recess (3011b) are both curves, and the shape of the sawtooth structure (301) is a sine curve.
6. A shaft bracket for a twin-screw ship according to claim 1 above, characterized in that, The protrusion (3011a) and the recess (3011b) are both broken lines, and the shapes of the protrusion (3011a) and the recess (3011b) are isosceles triangles.
7. A shaft bracket for a twin-screw ship according to claim 1 above, characterized in that, In the length direction of the bracket (300), the proportion range of the length of the sawtooth structure (301) relative to the total length of the bracket (300) is: 10% - 100%. In the length direction of the trailing edge of the bracket (300), the distance range between the tops of adjacent protrusions (3011a) is 100 - 800 mm. In the length direction of the bracket (300), the distance range between the top of an adjacent protrusion (3011a) and the bottom of the recess (3011b) is 40 - 400 mm.
8. An axle bracket for a twin-propeller ship according to claim 1 above, characterized in that, The bracket (300) is a plate-like structure. The dimension of the bracket (300) in the width direction of the hull (100) is much smaller than the dimension of the bracket (300) in the length direction of the hull (100). The sides of the bracket (300) in the width direction of the hull (100) are all arc-shaped, and the size of the bracket (300) in the width direction of the hull (100) gradually decreases in a manner close to both ends in the length direction of the hull (100).
9. A shaft bracket for a twin-screw ship according to claim 8 above, characterized in that, The size of the serrated structure (301) in the width direction of the hull (100) gradually decreases in a manner close to the end in the length direction of the hull (100), and the side of the serrated structure (301) in the width direction of the hull (100) and the side of the bracket (300) in the width direction of the hull (100) are continuously arranged.
10. A shaft bracket for a twin-propeller ship according to claim 1 above, characterized in that, The bracket (300) includes a front support portion (300a) and a rear support portion (300b). The front support portion (300a) and the rear support portion (300b) are arranged at intervals in sequence in a manner close to the propeller on the stern shaft (200). The serrated structure (301) is provided on both the front support portion (300a) and the rear support portion (300b). Both the front support portion (300a) and the rear support portion (300b) are plate-like structures. The number of the front support portions (300a) is one, and the number of the rear support portions (300b) is two. In the circumferential direction of the stern shaft (200), the front support portion (300a) and the rear support portion (300b) are arranged in a staggered manner.