Navigation equipment, ship shafting and method for controlling transverse vibration thereof

Abstract

The present invention relates to the technical field of marine equipment and provides marine equipment, a ship shaft system, and a method for controlling transverse vibration thereof. The ship shaft system comprises a propeller shaft assembly and a stern shaft assembly. The propeller shaft assembly comprises a thrust shaft extending to the stern shaft assembly. The stern shaft assembly comprises a stern tube and an outer cylinder. The stern tube is sleeved on the outer surface of the thrust shaft. The outer cylinder is sleeved on the outer surface of the stern tube. A friction damping energy dissipation structure is provided between the outer cylinder and the stern tube. The friction damping energy dissipation structure comprises a friction damping sleeve and a friction damping ring. The friction damping sleeve is provided with a pre-tightening portion. The friction damping rings are sleeved on the pre-tightening portion at intervals. The friction damping rings are further provided with an array of stacked piezoelectric ceramics. When the ship shaft system is subjected to transverse vibration, the stacked piezoelectric ceramics apply a pre-tightening force, causing the outer surface of the stern tube to rub against the inner surface of the friction damping sleeve, generating energy loss and suppressing the transverse vibration of the ship shaft system.

Description

Technical Field

[0001] The present invention relates to the technical field of navigation equipment, and in particular to a navigation equipment, a ship shaft system and a method for controlling the lateral vibration thereof. Background Art

[0002] The ship's shafting is an important part of the ship's power plant. Its task is to transmit the power generated by the ship's main engine to the propeller, and at the same time transmit the thrust generated by the propeller to the hull to propel the ship.

[0003] At present, with the development of larger ships, the stiffness of the hull, especially the stern, has decreased. In order to obtain higher propulsion efficiency, multi-axis propulsion systems are often used. Except for the shaft system on the centerline of the hull cross section, the rest of the ship's shaft system has a longer part away from the hull and extends into the water. The ship's shaft system extending into the water includes part of the propulsion shaft and the stern tube. The propulsion shaft and the stern tube are supported by outboard brackets. The stiffness of the outboard bracket is generally lower than the support stiffness inside the hull, which makes the bearing spacing of the ship's shaft system larger, resulting in a decrease in the natural frequency of the gyroscopic (transverse) vibration of the ship's shaft system.

[0004] When the number of propellers on a ship increases, the corresponding rotational speed also increases, so that the blade frequency of the fluid force acting on the propeller may be close to the lateral vibration natural frequency of the ship's shafting, which is in a downward trend, and the ship's shafting may produce cyclotron resonance. When this vibration exceeds the safe range that the ship's shafting structure can withstand, it will cause various failures of the ship's shafting structure and even cause vibration of the main engine body and hull. These factors will affect the operating efficiency and safety of the ship.

[0005] To this end, relevant technologies have been studied and found that the transverse vibration of the ship shafting has obvious time-varying characteristics. Its time-varying characteristics are derived from the influence of hull deformation, changes in bearing support stiffness, and the ship shafting rotational speed on dynamic characteristic parameters such as the natural frequency. With the development of larger and higher-speed ships, factors such as the lengthening of the shaft section of the ship shafting that protrudes from the hull have led to a decrease in the transverse vibration natural frequency of the ship shafting. Under the excitation of the uneven dynamic load of the propeller and the dynamic alternating load of the engine and gearbox, it is possible to excite multi-order modes of transverse time-varying vibration of the shafting as the frequency of the ship shafting changes. For this multi-modal time-varying transverse vibration of the ship shafting, relevant technologies optimize the support stiffness of the bearings at various positions of the ship shafting by modeling the overall dynamics of the ship shafting. However, this method still cannot effectively solve the problem of transverse vibration of the ship shafting during the entire operation of the ship. Summary of the Invention

[0006] A first aspect of the present invention provides a ship shafting system to address at least one of the above-mentioned technical defects in the prior art. When the ship shafting system is subjected to lateral vibration, the outer surface of the stern tube and the inner surface of the friction damping sleeve rub against each other, generating energy loss, thereby suppressing the lateral vibration of the ship shafting system.

[0007] A second aspect of the present invention provides a method for controlling lateral vibration of a ship shafting.

[0008] A third aspect of the present invention provides a marine device.

[0009] A first aspect of the present invention provides a ship shafting system, comprising a propulsion shaft assembly and a stern shaft assembly, wherein the propulsion shaft assembly comprises a thrust shaft, and the thrust shaft extends to the stern shaft assembly;

[0010] The stern shaft assembly includes:

[0011] a stern tube, sleeved on the outer surface of the thrust shaft;

[0012] An outer cylinder is sleeved on the outer surface of the stern tube and is coaxially arranged with the stern tube and the thrust shaft; a friction damping energy dissipation structure is provided between the outer cylinder and the stern tube, and the friction damping energy dissipation structure includes a friction damping sleeve and a friction damping ring, the friction damping sleeve is provided with a pre-tightening part, and the friction damping ring is sleeved on the pre-tightening part at intervals, and the friction damping ring is also provided with stacked piezoelectric ceramics in an array, and pressure is applied to the stacked piezoelectric ceramics to control the pre-tightening force applied by the friction damping ring to the pre-tightening part.

[0013] According to the ship shafting provided by the present invention, the friction damping collar comprises a collar body, wherein the collar body has an inner sidewall and an outer sidewall arranged opposite to each other;

[0014] The stacked piezoelectric ceramics are arranged on the outer side wall of the ring body, and a plurality of first protrusions are arranged in an array on the inner side wall of the ring body. The first protrusions abut the corresponding pre-tightening parts, and the plurality of first protrusions are arranged in a one-to-one correspondence with the stacked piezoelectric ceramics.

[0015] According to the ship shafting provided by the present invention, a plurality of second protrusions are arranged in an array on the outer wall of the collar body, the second protrusions abut against the inner wall of the outer cylinder, and the second protrusions are spaced apart from the first protrusions.

[0016] According to the ship shafting provided by the present invention, the inner wall of the outer cylinder is provided with a limiting groove, the limiting groove is arranged in a one-to-one correspondence with the second protrusion, and the second protrusion is embedded in the limiting groove.

[0017] According to the ship shafting provided by the present invention, the friction damping sleeve includes a main body cylinder section and a pre-tightening cylinder section connected to each other. The pre-tightening cylinder section is provided with a plurality of pre-tightening grooves in an array along its own circumferential direction starting from the end face, and the pre-tightening portion is formed between two adjacent pre-tightening grooves.

[0018] According to the ship shafting provided by the present invention, the stern shaft assembly also includes a tuned damping structure. The interior of the thrust shaft has a hollow shaft cavity. The tuned damping structure is installed at a preset position in the hollow shaft cavity to suppress the lateral vibration of the ship shafting.

[0019] According to the ship shafting provided by the present invention, the tuned damping structure includes a piezoelectric damping elastomer and a counterweight. The piezoelectric damping elastomer has a hollow cavity inside, and the counterweight is arranged in the hollow cavity. The outer surface of the piezoelectric damping elastomer is provided with first grooves at intervals along its own axial direction.

[0020] According to the ship shafting provided by the present invention, the outer surface of the piezoelectric damping elastomer is provided with a second groove along the circumferential direction.

[0021] A second aspect of the present invention provides a method for controlling lateral vibration of a ship shafting system, which is implemented by any of the above-mentioned ship shafting systems and includes the following steps:

[0022] Obtain information on the position of the ship's shaft system where transverse vibration is about to occur;

[0023] applying a corresponding voltage to the stacked piezoelectric ceramics on the opposite side of the acquired position to actuate the stacked piezoelectric ceramics, converting electrical energy into mechanical energy to push the friction damping ring to displace in its own radial direction, thereby applying a preload force to the friction damping sleeve; and / or

[0024] Tuned damping structures are distributed at the modal array sensitive points of the thrust shaft to control the time-varying vibration caused by the lateral vibration natural frequency migration of the ship shafting.

[0025] A third aspect of the present invention provides a navigation device, comprising a hull and any one of the above-mentioned ship shafting systems, wherein the ship shafting system is arranged on the hull.

[0026] The ship shafting system provided by the present invention comprises a friction damping energy dissipation structure disposed between an outer tube and a stern tube. The friction damping energy dissipation structure comprises a friction damping sleeve and a friction damping ring. The friction damping sleeve is provided with a preload portion, and the friction damping rings are spaced apart and sleeved on the preload portion. Stacked piezoelectric ceramics are arrayed on the friction damping rings. When pressure is applied to the stacked piezoelectric ceramics, the preload force applied by the friction damping rings on the preload portion is controlled. When the ship shafting system detects that vibration is imminent, a voltage is applied to the stacked piezoelectric ceramics, which actuates the stacked piezoelectric ceramics to push the friction damping rings to apply a certain preload force to the friction damping sleeve, thereby achieving close contact between the friction damping sleeve and the stern tube. When the ship shafting system is subjected to lateral vibration, the stacked piezoelectric ceramics apply the preload force, causing the outer surface of the stern tube to rub against the inner surface of the friction damping sleeve, generating energy loss and thereby suppressing lateral vibration of the ship shafting system. In addition, a tuned damping structure is installed at the sensitive position of the thrust shaft vibration to convert the vibration kinetic energy into electrical energy, and the timeliness and stability of suppressing lateral vibration are further expanded through internal energy conversion.

[0027] The method for controlling the transverse vibration of a ship shafting provided by the present invention can effectively control the transverse vibration of the ship shafting that may be excited by pulsating impacts and uneven dynamic loads during the entire operation of the ship.

[0028] The navigation equipment provided by the present invention includes the above-mentioned ship shafting and thus has all the advantages of the above-mentioned ship shafting. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 is a radial cross-sectional view of the ship shafting provided by the present invention;

[0031] Figure 2 This is a cross-sectional view of the ship shafting provided by the present invention along the axial direction;

[0032] Figure 3 This is a schematic structural diagram of the ship shafting system provided by the present invention;

[0033] Figure 4 This is a schematic structural diagram of a friction damping sleeve in a ship shafting system provided by the present invention;

[0034] Figure 5 This is a schematic structural diagram of a friction damping collar in a ship shafting system provided by the present invention;

[0035] Figure 6 Schematic diagram of the structure of the tuned damping structure in the ship shafting provided by the present invention;

[0036] Figure 7 It is a structural schematic diagram of another embodiment of the ship shafting provided by the present invention.

[0037] Reference numerals:

[0038] 10. Thrust shaft;

[0039] 20. Stern tube;

[0040] 30. Outer cylinder;

[0041] 40. Friction damping energy dissipation structure; 41. Friction damping sleeve; 411. Main body cylinder section; 412. Preload cylinder section; 4121. Preload groove; 4122. Preload portion; 42. Friction damping collar; 421. Collar body; 422. First protrusion; 423. Second protrusion; 43. Stacked piezoelectric ceramic;

[0042] 50. Tuned damping structure; 51. Piezoresistive damping elastomer; 511. First groove; 512. Second groove; 52. Counterweight. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0044] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0045] In the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0046] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0047] As my country's ships develop towards higher speeds, larger sizes, and higher power, demands for improved comfort, stealth, impact resistance, and reduced hull fatigue excitation are becoming increasingly urgent. As the primary source of ship vibration, the reliability, effectiveness, and stability of shafting lateral vibration control are becoming increasingly important.

[0048] Due to the harsh operating conditions of ship shafting and its susceptibility to various factors such as uneven dynamic load excitation, the bearing support stiffness of ship shafting exhibits time-varying characteristics. Therefore, controlling the transverse vibration of ship shafting is necessary by optimizing the shafting structure and support conditions or by using traditional vibration control methods. Due to the limitations of the supercavitation effect, the rotational speed of ship shafting is generally low. Previous studies of transverse vibration of ship shafting have generally simplified the model as a rigid body or ignored the influence of rotational speed on transverse vibration.

[0049] At present, the stiffness of the hull, especially the stern, of large-scale and high-speed ships has decreased. In order to obtain higher propulsion efficiency, multi-shaft propulsion systems are often used. In the ship's shaft system, except for the part on the centerline of the hull cross-section, the rest of the ship's shaft system has a longer part extending away from the hull into the water. The ship's shaft system extending into the water includes part of the propulsion shaft and the stern tube, which are supported by outboard brackets. The stiffness of the outboard bracket is generally lower than the support stiffness inside the hull, which makes the bearing spacing of the ship's shaft system larger, resulting in a decrease in the natural frequency of the gyroscopic (transverse) vibration of the ship's shaft system.

[0050] When the number of propellers on a ship increases, the corresponding rotational speed also increases, so that the blade frequency of the fluid force acting on the propeller may be close to the lateral vibration natural frequency of the ship's shafting, which is in a downward trend, and the ship's shafting may produce cyclotron resonance. When this vibration exceeds the safe range that the ship's shafting structure can withstand, it will cause various failures of the ship's shafting structure and even cause vibration of the main engine body and hull. These factors will affect the operating efficiency and safety of the ship.

[0051] To this end, relevant research has found that the transverse vibration of a ship's shafting exhibits significant time-varying characteristics. These time-varying characteristics stem from the influence of hull deformation, changes in bearing support stiffness, and the shafting's rotational speed on dynamic parameters such as the natural frequency. With the development of larger and faster ships, factors such as the lengthening of the shaft section extending beyond the hull have led to a decrease in the natural frequency of the shafting's transverse vibration. Under the excitation of uneven propeller dynamic loads and dynamic alternating loads from the engine and gearbox, multiple modes of transverse time-varying vibration can be generated as the shafting's rotational frequency changes. To address this multi-modal, time-varying transverse vibration of the shafting, relevant technologies have optimized the support stiffness of bearings at various locations within the shafting by modeling the overall dynamics of the shafting. However, this approach still fails to effectively address the transverse vibration of the shafting throughout the entire ship's operation. Therefore, controlling transverse vibration of the shafting remains a challenging issue in ship design, operation, and maintenance. Furthermore, traditional passive vibration control methods struggle to reliably and effectively control the multi-modal, time-varying transverse vibration of the shafting. Furthermore, the active vibration control methods developed in recent years cannot circumvent the transverse vibration characteristics of the shafting. Due to the shortcomings of time-varying closed-loop control models such as difficulty in accurately establishing and controlling time delays, the effectiveness of active vibration control in practical applications is greatly reduced.

[0052] The following combination Figures 1 to 7 It should be understood that the following description is merely an illustrative embodiment of the present invention and does not constitute any limitation to the present invention.

[0053] See Figures 1 to 5 A first aspect of an embodiment of the present invention provides a ship shafting system, which includes a propulsion shaft assembly and a stern shaft assembly. The propulsion shaft assembly includes a thrust shaft 10, and the thrust shaft 10 extends to the stern shaft assembly.

[0054] Among them, the stern shaft assembly includes a stern tube 20 and an outer tube 30. The stern tube 20 is sleeved on the outer surface of the thrust shaft 10 and is coaxially arranged with the thrust shaft 10; the outer tube 30 is sleeved on the outer surface of the stern tube 20 and is coaxially arranged with the stern tube 20; a friction damping energy dissipation structure 40 is provided between the outer tube 30 and the stern tube 20, and the friction damping energy dissipation structure 40 includes a friction damping sleeve 41 and a friction damping ring 42. A pre-tightening portion 4122 is provided on the friction damping sleeve 41, and the friction damping ring 42 is sleeved on the pre-tightening portion 4122 at intervals. Stacked piezoelectric ceramics 43 are arrayed on the friction damping ring 42. After the stacked piezoelectric ceramics 43 apply pressure, the pre-tightening force applied by the friction damping ring 42 on the pre-tightening portion 4122 is controlled.

[0055] When the ship's shafting is detected to be about to vibrate laterally, a voltage is applied to the stacked piezoelectric ceramic 43, causing it to extend in its Z-axis direction, converting electrical energy into mechanical energy. This actuates the stacked piezoelectric ceramic 43, pushing the friction damping ring 42 radially. This applies a certain preload to the friction damping sleeve 41, ensuring a uniform and stable preload. This in turn creates close contact between the friction damping sleeve 41 and the stern tube 20, increasing friction between them. When the ship's shafting is subject to transverse vibration, the outer surface of the stern tube 20 rubs against the inner surface of the friction damping sleeve 41, generating energy loss and suppressing the transverse vibration of the ship's shafting. Specifically, the frictional energy dissipation between the inner wall of the friction damping sleeve 41 and the outer wall of the stern tube 20 suppresses the transverse bending vibration of the stern tube 20, thereby improving the stern support stiffness of the thrust shaft 10.

[0056] It will be appreciated that the present invention disposes a friction damping energy dissipation structure 40 between the outer cylinder 30 and the stern tube 20. The friction damping energy dissipation structure 40 comprises a friction damping sleeve 41 and a friction damping collar 42. The friction damping sleeve 41 is provided with a preload portion 4122, and the friction damping collar 42 is spaced apart and sleeved around the preload portion 4122. Stacked piezoelectric ceramics 43 are arrayed on the friction damping collar 42. When pressure is applied to the stacked piezoelectric ceramics 43, the preload force applied by the friction damping collar 42 to the preload portion 4122 is controlled. When the ship's shafting is detected to be about to vibrate, a voltage is applied to the stacked piezoelectric ceramics 43, which actuates the stacked piezoelectric ceramics 43 to push the friction damping collar 42 to apply a certain preload force to the friction damping sleeve 41, thereby ensuring close contact between the friction damping sleeve 41 and the stern tube 20. When the ship's shafting is subjected to lateral vibration, the outer surface of the stern tube 20 and the inner surface of the friction damping sleeve 41 rub against each other, resulting in energy loss, which plays a role in suppressing the lateral vibration of the ship's shafting.

[0057] like Figure 4As shown, in some embodiments of the present invention, the friction damping ring 42 includes a ring body 421, the ring body 421 has an inner side wall and an outer side wall that are relatively arranged, and the stacked piezoelectric ceramics 43 are arranged on the outer side wall of the ring body 421; a plurality of first protrusions 422 are arranged in an array on the inner side wall of the ring body 421, the first protrusions 422 abut against the corresponding pre-tightening portions 4122, and the plurality of first protrusions 422 are arranged in a one-to-one correspondence with the stacked piezoelectric ceramics 43.

[0058] When it is detected that the ship shaft system is about to vibrate, after voltage is applied to the stacked piezoelectric ceramic 43, the stacked piezoelectric ceramic 43 is actuated to push the friction damping ring 42 to drive the first protrusion 422 to apply a certain pre-tightening force to the friction damping sleeve 41, so that the friction damping sleeve 41 is in close contact with the stern tube 20.

[0059] Compared with abutting the inner side wall of the collar body 421 against the pre-tightening portion 4122, using the first protrusion 422 to abut the corresponding pre-tightening portion 4122 can reduce the contact area between the collar body 421 and the pre-tightening portion 4122. When the pressure remains unchanged, the force area between the collar body 421 and the pre-tightening portion 4122 is reduced, and the pressure of the collar body 421 on the pre-tightening portion 4122 can be more obvious, thereby making the control of the pre-tightening force more accurate.

[0060] like Figure 4 As shown, in some embodiments of the present invention, a plurality of second protrusions 423 are arranged in an array on the outer wall of the collar body 421 , the second protrusions 423 abut against the inner wall of the outer cylinder 30 , and the second protrusions 423 are spaced apart from the first protrusions 422 .

[0061] When voltage is applied to the stacked piezoelectric ceramic 43, the stacked piezoelectric ceramic 43 is actuated to push the friction damping ring 42, which drives the first protrusion 422 to apply a certain pre-tightening force to the friction damping sleeve 41, so that the friction damping sleeve 41 is in close contact with the stern tube 20; at the same time, the friction damping ring 42 is pushed to drive the second protrusion 423 to squeeze the outer tube 30. Since the cross-sectional area of ​​the outer tube 30 remains unchanged, the outer tube 30 reacts on the second protrusion 423, so that the second protrusion 423 and the friction damping ring 42 squeeze the friction damping sleeve 41, thereby increasing the pre-tightening force on the friction damping sleeve 41.

[0062] In some embodiments of the present invention, a limiting groove (not shown in the figure) is provided on the inner wall of the outer cylinder 30, and the limiting groove is arranged in a one-to-one correspondence with the second protrusion 423. When the outer cylinder 30 is sleeved on the outside of the ring body 421, the second protrusion 423 is embedded in the corresponding limiting groove to fix the position of the ring body 421, which can also achieve a fixing effect.

[0063] like Figure 3As shown, in some embodiments of the present invention, the friction damping sleeve 41 includes a main body cylinder section 411 and a pre-tightening cylinder section 412 that are connected to each other. The pre-tightening cylinder section 412 is provided with a plurality of pre-tightening grooves 4121 in an array along its own circumferential direction starting from the end face, and the pre-tightening portion 4122 is a portion formed between two adjacent pre-tightening grooves 4121.

[0064] The pre-tightening grooves 4121 may be provided in two, three, or four groups, and the specific arrangement may be determined based on actual usage. The number of pre-tightening portions 4122 may correspond to the number of first protrusions 422 on the friction damping collar 42, so that the first protrusions 422 correspond one-to-one to the pre-tightening portions 4122.

[0065] Under normal circumstances, the cross-sectional areas of the main body section 411 and the preload section 412 are equal, that is, the diameters of the main body section 411 and the preload section 412 are equal. When the preload portions 4122 of the preload section 412 are subjected to a preload force, the width of the preload groove 4121 decreases, thereby reducing the cross-sectional area of ​​the preload section 412. The preload section 412 tightly embraces the outer surface of the stern tube 20, ensuring close contact between the preload section 412 and the stern tube 20.

[0066] In other words, part of the friction damping sleeve 41 is intact, while another part is slotted axially from the end face, forming a petal-shaped structure. The stacked piezoelectric ceramics 43 apply a stable and uniform preload to the multiple petal-shaped structures of the friction damping sleeve 41. Under the action of this preload, the petal-shaped friction damping sleeve 41 and the stern tube 20 are in close contact. When the ship's shafting is subjected to lateral vibration, the stern tube 20 rubs against the surface of the petal-shaped friction damping sleeve 41, generating energy loss and suppressing the lateral vibration of the ship's shafting.

[0067] like Figure 6 and Figure 7 As shown, based on the above embodiments, different from the above embodiments, the stern shaft assembly also includes a tuned damping structure 50, the interior of the thrust shaft 10 has a hollow shaft cavity, and the tuned damping structure 50 is installed at a preset position in the hollow shaft cavity to suppress the lateral vibration of the ship's shaft system.

[0068] The preset position is a position sensitive to each modal formation of the inner wall of the thrust shaft 10 determined in advance through model simulation.

[0069] Specifically, if Figure 6As shown, the tuned damping structure 50 includes a piezoelectric damping elastomer 51 and a counterweight 52. The piezoelectric damping elastomer 51 has a hollow cavity inside, and the counterweight 52 is arranged in the hollow cavity. The piezoelectric damping elastomer 51 can be made of piezoelectric ceramic material, and the outer surface of the piezoelectric damping elastomer 51 is provided with first grooves 511 along its own axial intervals.

[0070] When the tuned damping structure 50 is installed in the hollow shaft cavity of the thrust shaft 10, the gas in the hollow shaft cavity is discharged along the first groove 511, reducing the resistance during the installation of the tuned damping structure 50, reducing the installation difficulty of the tuned damping structure 50, and improving the installation efficiency of the tuned damping structure 50.

[0071] The counterweight 52 can be understood as a mass block with a certain weight, which is mainly used to increase gravity.

[0072] After the tuned damping structure 50 is installed in the hollow shaft cavity, the outer wall of the piezoelectric damping elastomer 51 and the inner wall of the thrust shaft 10 contact each other, so as to control the lateral vibration of the ship shaft system that may be excited by pulsating impact and uneven dynamic load during the entire operation of the ship.

[0073] like Figure 6 As shown, in some embodiments of the present invention, a second groove 512 is provided along the circumferential direction on the outer surface of the piezoelectric damping elastic body 51. Providing the second groove 512 can reduce the contact area between the piezoelectric damping elastic body 51 and the thrust shaft 10. When the pressure remains constant, reducing the force-bearing area between the piezoelectric damping elastic body 51 and the thrust shaft 10 can increase the pressure exerted by the thrust shaft 10 on the piezoelectric damping elastic body 51.

[0074] In some embodiments of the present invention, the propulsion shaft assembly also includes an intermediate shaft and a propeller shaft. The thrust shaft 10, the intermediate shaft, the stern shaft assembly and the propeller shaft are connected in sequence. The thrust shaft 10 is used to connect to the ship's main engine, and the propeller shaft is used to connect to the propeller. The power generated by the ship's main engine is transmitted to the propeller through the ship's shaft system, and at the same time, the thrust generated by the propeller is transmitted to the hull to propel the ship's navigation.

[0075] Specifically, the thrust shaft 10 is supported on thrust bearings, the intermediate shaft is supported by intermediate bearings, and the stern shaft extends out the stern through the axle tube. The thrust shaft 10, intermediate shaft, and stern shaft are bolted together via flanges. The propeller is secured to the stern shaft with a key and nut. For maintenance purposes, a stern shaft tunnel is provided. This tunnel has a window for lifting the shaft system and is normally sealed with iron plates. The bulkhead between the stern shaft tunnel and the engine room is equipped with a watertight door and a bulkhead stuffing box for the intermediate shaft to pass through.

[0076] It should be noted that the stacked piezoelectric ceramic 43 is a stacked piezoelectric ceramic, which is formed by laminating, bonding and co-firing a piezoelectric ceramic substrate. Generally, the thickness of a single-layer piezoelectric ceramic substrate is about 100 μm. The piezoelectric ceramic can withstand great pressure and has high rigidity.

[0077] After multiple layers of ceramic sheets are connected to form a stacked piezoelectric ceramic, when voltage is applied to the ceramic, the piezoelectric ceramic will extend in the Z-axis direction, and the electrical energy will be converted into mechanical energy through the upper and lower end surfaces of the stacked piezoelectric ceramic 43 and output to the outer tube 30 and the stern tube 20.

[0078] The maximum typical elongation of stacked piezoelectric ceramics is 0.1%-0.2% of the ceramic length. Low-voltage piezoelectric ceramics can operate in a voltage range of 0-150V, while high-voltage piezoelectric ceramics can operate in a voltage range of 0-500V or 1000V.

[0079] Therefore, different voltages applied to the stacked piezoelectric ceramics 43 will cause different pre-tightening forces of the friction damping ring 42 on the friction damping sleeve 41, and further cause different pre-tightening forces of the friction damping sleeve 41 on the stern tube 20, resulting in different degrees of tightness between the friction damping sleeve 41 and the stern tube 20, thereby generating different friction energy losses, thereby achieving controllable lateral vibration of the ship's shafting.

[0080] Furthermore, the wide control voltage range of the stacked piezoelectric ceramics 43 broadens the vibration control frequency band to suppress the time-varying lateral gyration vibration of the entire ship's shafting system, thereby achieving highly stable and effective control of the lateral vibration of the shafting system of large ships.

[0081] A second aspect of an embodiment of the present invention provides a method for controlling lateral vibration of a ship shafting system, which is implemented based on the above-mentioned ship shafting system and includes the following steps:

[0082] Step S01: obtaining position information of a ship shaft system where lateral vibration is about to occur;

[0083] Step S02: Apply a corresponding voltage to the stacked piezoelectric ceramic 43 on the opposite side of the acquired position to actuate the stacked piezoelectric ceramic 43. The stacked piezoelectric ceramic 43 will extend in its own Z-axis direction, converting electrical energy into mechanical energy. That is, the stacked piezoelectric ceramic 43 is actuated to push the friction damping ring 42 to displace in its own radial direction, applying a certain preload force to the friction damping sleeve 41, so that the friction damping sleeve 41 is subjected to a uniform and stable preload force, thereby achieving close contact between the friction damping sleeve 41 and the stern tube 20, thereby increasing the friction between the friction damping sleeve 41 and the stern tube 20.

[0084] When the ship's shafting is subjected to lateral vibration, the outer surface of the stern tube 20 and the inner surface of the friction damping sleeve 41 rub against each other, generating energy loss. The friction energy dissipation principle is utilized to suppress the lateral vibration of the ship's shafting, that is, the friction energy dissipation between the inner wall of the friction damping sleeve 41 and the outer wall of the stern tube 20 suppresses the lateral bending vibration of the stern tube 20, thereby improving the stern support stiffness of the thrust shaft 10.

[0085] Step S03: When the ship shafting system vibrates laterally due to pulsating shocks and uneven dynamic loads during operation, the tuned damping structure 50 utilizes the piezoelectric effect of the piezoelectric ceramics in the piezoelectric damping elastomer 51 to convert the mechanical energy generated by the vibration of the ship shafting system into electrical energy, and consumes the electrical energy through the inherent resistance of the ship shafting system to control the multi-modal time-varying lateral vibration of the ship shafting system.

[0086] The tuned damping structure 50 can be configured in two different ways to control the multi-modal time-varying lateral vibration of the ship's shafting.

[0087] like Figure 6 As shown, multiple tuned damping structures 50 can be distributed at sensitive points of each mode array of the thrust shaft to control the lateral vibration of the ship shaft system that may be excited by pulsating impact and uneven dynamic load during the entire operation of the ship.

[0088] like Figure 7 As shown, the distributed tuned damping structure 50 can be split into multiple separately arranged damper groups at each modal array sensitive point of the thrust shaft, so that the multiple separately arranged damper groups form a multiple tuned mass damper subsystem, and the natural frequency and other related parameters of each damper in each damper group are set to be unequal, and the natural frequency and other related parameters of each damper in each damper group are distributed according to a certain rule, so as to achieve optimal control of the time-varying vibration caused by the migration of the lateral vibration natural frequency of the ship shaft system during the operation of the ship.

[0089] The method for controlling the lateral vibration of a ship shafting provided by an embodiment of the present invention solves the problems that traditional passive control technology is difficult to control the multi-modal time-varying lateral vibration of a ship shafting and that active control technology is difficult to establish a closed-loop control model through a semi-active control method.

[0090] A third aspect of the present invention provides a navigation device, comprising a hull and any one of the above-mentioned ship shafting systems, wherein the ship shafting system is arranged on the hull. The diesel engine drives the propeller through the thrust shaft 10, the adjusting short shaft, the intermediate shaft and the stern shaft.

[0091] The navigation equipment may be a ship or vessel or other equipment used for navigation. Since the navigation equipment includes the above-mentioned ship shafting, it has all the above-mentioned advantages.

[0092] It should be noted that the technical solutions in the various embodiments of the present invention can be combined with each other, but the basis for the mutual combination is that it can be implemented by ordinary technicians in this field; when the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist, that is, it does not fall within the scope of protection of the present invention.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A ship shafting system, characterized in that: The invention comprises a propulsion shaft assembly and a stern shaft assembly, wherein the propulsion shaft assembly comprises a thrust shaft, and the thrust shaft extends to the stern shaft assembly; The stern shaft assembly includes: a stern tube, sleeved on the outer surface of the thrust shaft; An outer cylinder is sleeved on the outer surface of the stern tube and is coaxially arranged with the stern tube and the thrust shaft; a friction damping energy dissipation structure is provided between the outer cylinder and the stern tube, the friction damping energy dissipation structure comprising a friction damping sleeve and a friction damping ring, the friction damping sleeve comprising a main body tube section and a pre-tightening tube section connected to each other, the pre-tightening tube section being provided with a plurality of pre-tightening grooves in an array along its own circumferential direction starting from the end surface, a pre-tightening portion being formed between two adjacent pre-tightening grooves, the friction damping ring being sleeved on the pre-tightening portion at intervals, the friction damping ring comprising a ring body, the ring body having an inner sidewall and an outer sidewall arranged oppositely; a stacked piezoelectric ceramic is provided on the outer sidewall of the ring body, a plurality of first protrusions are arranged in an array on the inner sidewall of the ring body, the first protrusions abutting against the corresponding pre-tightening portions, and the plurality of first protrusions are arranged in a one-to-one correspondence with the stacked piezoelectric ceramics; a voltage is applied to the stacked piezoelectric ceramics to control the pre-tightening force applied by the friction damping ring to the pre-tightening portion.

2. The ship shafting according to claim 1, characterized in that: A plurality of second protrusions are arranged in an array on the outer side wall of the collar body. The second protrusions abut against the inner wall of the outer cylinder, and the second protrusions are spaced apart from the first protrusions.

3. The ship shafting according to claim 2, characterized in that: The inner wall of the outer cylinder is provided with a limiting groove, the limiting groove is arranged in a one-to-one correspondence with the second protrusion, and the second protrusion is embedded in the limiting groove.

4. The ship shafting according to any one of claims 1 to 3, characterized in that: The stern shaft assembly also includes a tuned damping structure. The interior of the thrust shaft has a hollow shaft cavity. The tuned damping structure is installed at a preset position in the hollow shaft cavity to suppress lateral vibration of the ship's shafting.

5. The ship shafting according to claim 4, characterized in that: The tuned damping structure includes a piezoelectric damping elastomer and a counterweight. The piezoelectric damping elastomer has a hollow cavity inside, and the counterweight is arranged in the hollow cavity. The outer surface of the piezoelectric damping elastomer is provided with first grooves at intervals along its axial direction.

6. The ship shafting according to claim 5, characterized in that: A second groove is provided on the outer surface of the piezoelectric damping elastic body along the circumferential direction.

7. A method for controlling lateral vibration of a ship shafting system, implemented based on the ship shafting system according to any one of claims 1 to 6, characterized in that: The steps include: Obtain information on the position of the ship's shaft system where transverse vibration is about to occur; applying a corresponding voltage to the stacked piezoelectric ceramics on the opposite side of the acquired position to actuate the stacked piezoelectric ceramics, converting electrical energy into mechanical energy to push the friction damping ring to displace in its own radial direction, thereby applying a preload force to the friction damping sleeve; and / or Tuned damping structures are distributed at the modal array sensitive points of the thrust shaft to control the time-varying vibration caused by the lateral vibration natural frequency migration of the ship shafting.

8. A navigation device, characterized in that: The invention comprises a hull and the ship shafting according to any one of claims 1 to 6, wherein the ship shafting is arranged on the hull.

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