Ship shafting centering method

Abstract

The invention relates to the technical field of ship construction, in particular to a ship shafting centering method, which utilizes a telescope and a core shift light target to realize advanced centering of a shafting and break through the thought that original shafting centering can only be carried out after the structure of a whole ship is complete, so that the whole engineering arrangement of ship construction is more flexible, and the construction period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of shipbuilding, and in particular to a method for centering a ship shaft system. Background Art

[0002] Traditional shaft alignment is usually done by flange alignment: after determining the position of the stern shaft, the position of each intermediate shaft, thrust bearing, main engine and other shaft equipment is found forward through the opening and offset value of the shaft flange, and then the shaft flange bolts are connected; after the ship is in clean water, the shaft load is measured and adjusted to meet the requirements, and the shaft equipment is finally installed; flange alignment is sometimes done after the ship is launched (wet alignment) and sometimes in the dock (dry alignment), but both dry and wet alignment are done after the entire ship structure is complete. Traditional shaft alignment has high requirements for the integrity of the hull structure, which greatly restricts the entire construction arrangement of the ship. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a ship shafting alignment method for solving the problem that the prior art shafting alignment has high requirements on the integrity of the hull structure, thereby placing great restrictions on the entire construction arrangement of the ship.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a ship shafting alignment method, the alignment method comprising:

[0005] Determine a bow reference point and a stern reference point, wherein a line connecting the bow reference point and the stern reference point is a theoretical axis of a ship shaft system;

[0006] Placing a telescope on one side of the stern reference point close to the stern end, and adjusting the position of the telescope so that the center of the telescope is in the same straight line as the theoretical axis of the ship shaft system;

[0007] Calculating the bearing displacement data required for each bearing when aligning the shaft system, wherein the bearing displacement data is used to indicate the relative position of the corresponding bearing and the theoretical axis of the ship shaft system;

[0008] Manufacturing a corresponding decentered light target, wherein the center of the decentered light target is on the same straight line as the center line of the corresponding bearing, and the target core marking line of the decentered light target is higher or lower than the center of the decentered light target according to the bearing displacement data;

[0009] Manufacturing a corresponding dummy shaft, and installing the corresponding eccentric light targets at both ends of the dummy shaft, respectively, wherein the axis of the dummy shaft and the center of the eccentric light target are located on the same straight line;

[0010] placing each of the bearings on a corresponding equipment base, wherein the base is configured to be adjustable in vertical height;

[0011] Determine the position of the bearing after the axis system is centered, coaxially insert the dummy axis on the corresponding bearing, and adjust the position of the bearing so that the center of the telescope coincides with the target core marking line of the corresponding deflected optical target. At this time, the position of the bearing is the position of the bearing after the axis system is centered;

[0012] Each shaft is correspondingly mounted on the bearings at the determined positions.

[0013] Optionally, the calculation of the bearing displacement data required for each bearing when aligning the shaft system includes:

[0014] Through finite element modeling, the structural deformation data of each bearing in two structural states are calculated: in the state of shaft alignment, in the state of complete ship structure and after the whole ship is launched, and in the state of free floating;

[0015] Based on the structural deformation data of each bearing under the two structural states and combined with the bearing displacement set in the shafting alignment calculation book, the bearing displacement results required for each bearing when the shafting is aligned are calculated.

[0016] Optionally, the calculation of the bearing displacement results required for each bearing when the shaft system is aligned includes:

[0017] Calculate the relative deformation data of the entire ship after launching and the alignment state of the shafting;

[0018] Establish a coordinate system, in which the horizontal coordinate is the distribution position of each bearing, the vertical coordinate is the relative deformation corresponding to each bearing, and draw a straight line in the coordinate system with the connecting line of the relative deformation of the stern tube front bearing and the stern tube rear bearing, and extend it to the bow, measure and calculate the structural deformation of the straight line relative to other bearings;

[0019] Optimizing the structural deformation of the straight line relative to other bearings to facilitate shaft system construction;

[0020] Combined with the displacement of each bearing set in the shafting alignment calculation book, the final bearing displacement result is obtained.

[0021] Optionally, the horizontal coordinate is plotted at a ratio of 1:1, and the vertical coordinate is plotted at a ratio of 1:100.

[0022] Optionally, the adjusting the position of the telescope so that the center of the telescope is in a straight line with the theoretical axis of the ship shaft system includes:

[0023] A reference target is respectively arranged at the bow reference point and the stern reference point, the target core marking line of the reference target coincides with the center of the reference target, and the target core marking lines of the two reference targets coincide with the bow reference point and the stern reference point respectively;

[0024] The position of the telescope is adjusted so that the center of the telescope coincides with the target core marking lines of the two reference targets.

[0025] Optionally, the bow reference point is set at the front end of the thrust bearing, and the stern reference point is set at the theoretical design center position of the propeller.

[0026] Optionally, the bow reference point and the stern reference point are acquired based on an average baseline and shafting arrangement diagram data.

[0027] Optionally, the centering method further includes marking the completed deflected optical target with corresponding marking numbers and upper and lower markings.

[0028] Optionally, the principles of finite element modeling include:

[0029] The main hull is simulated by plate beam units, the supporting beam plate units of the hull structure are simulated by spring units, and the side piers and slats on the beams are simulated by spring units, which only bear pressure but not tension.

[0030] Finite element calculations need to consider the influence of uniformly distributed loads and concentrated loads on the weight center of gravity of the structure and support, equipment, and the configuration of the cabins after the entire ship is launched.

[0031] Optionally, an adjusting bolt is provided on the base, and the vertical height of the base is adjusted by the adjusting bolt.

[0032] In a ship shaft alignment method of the present invention, a telescope and an eccentric optical target are used to achieve early alignment of the shaft, breaking the original idea that the shaft alignment must be performed after the entire ship structure is complete, making the entire engineering arrangement of ship construction more flexible and shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a simplified schematic diagram of the arrangement of a ship shaft system according to an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of relative deformation in one embodiment of the present invention, modeled and plotted in proportion;

[0035] Figure 3 is a schematic diagram of the relative deformation after optimization in one embodiment of the present invention, which is modeled and plotted in proportion;

[0036] Figure 4 It is a schematic diagram of the overall structure of the ship shafting alignment in one embodiment of the present invention;

[0037] Figure 5 It is a schematic diagram of the position of the target core marking line and the center of the deflected light target in one embodiment of the present invention;

[0038] Figure 6It is a schematic diagram of the matching structure of the dummy axis and the deflected optical target in one embodiment of the present invention. DETAILED DESCRIPTION

[0039] Refer to the following Figure 1 and Figure 6 A method for aligning a ship shafting of the present invention is described. In the description of this embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiment", "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 present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0040] refer to Figure 1 The ship shaft system is arranged from the stern to the bow, in order: propeller shaft 1, 1# intermediate shaft 2, 2# intermediate shaft 3, 3# intermediate shaft 4, 4# intermediate shaft 5, 5# intermediate shaft 6, 6# intermediate shaft 7 and thrust shaft 8. Correspondingly, the propeller shaft 1 is provided with a stern tube rear bearing 11 and a stern tube front bearing 12. Intermediate bearings are provided on each intermediate shaft. The intermediate bearings are 7# intermediate bearing 13, 6# intermediate bearing 14, 5# intermediate bearing 15, 4# intermediate bearing 16, 3# intermediate bearing 17, 2# intermediate bearing 18, 1# intermediate bearing 19 from the stern to the bow. The thrust shaft 8 is provided with a thrust rear bearing 9 and a thrust front bearing 10.

[0041] refer to Figure 2-Figure 6 The embodiment of the present invention provides a method for centering a ship shaft system, which is generally performed after the ship structure is loaded to 10M and 20M and the double bottom structure tightness and strength test of the engine room is completed. The centering method includes:

[0042] Step S1, determine the bow reference point 29 and the stern reference point 28. The line connecting the bow reference point 29 and the stern reference point 28 is the theoretical axis 27 of the ship's shafting. The selection of the bow reference point 29 and the stern reference point 28 is obtained based on the average baseline and the shafting arrangement diagram data. That is, based on the average baseline and the shafting arrangement diagram, the theoretical axis 27 of the ship's shafting is determined, and the bow reference point 29 and the stern reference point 28 are points on the theoretical axis 27 of the ship's shafting.

[0043] Optionally, the bow reference point 29 is set at the bow end of the thrust front bearing, and the stern reference point 28 is set at the theoretical design center position of the propeller.

[0044] Step S2, placing a telescope 26 on the side of the stern reference point 28 close to the stern end, and adjusting the position of the telescope 26 so that the center of the telescope 26 is in the same straight line with the theoretical axis 27 of the ship's shaft system.

[0045] Furthermore, a reference target is set at the bow reference point 29 and the stern reference point 28 respectively. The target core marking line of the reference target coincides with the center of the reference target. The target core marking lines of the two reference targets coincide with the bow reference point 29 and the stern reference point 28 respectively. The target core marking lines of the two reference targets are illuminated by the telescope 26, and the position of the telescope 26 is adjusted so that the center of the telescope 26 coincides with the target core marking lines of the two reference targets, so that the center of the telescope 26 is in the same straight line with the theoretical axis 27 of the ship's shaft system.

[0046] Step S3, calculating the bearing displacement data required for each bearing when the shaft system is aligned. The bearing displacement data is used to indicate the relative position of the corresponding bearing and the theoretical axis 27 of the ship shaft system.

[0047] Furthermore, the bearing displacement data required for each bearing when the shaft system is aligned is calculated, including:

[0048] Step S31, through finite element modeling, respectively calculate the structural deformation data of each bearing in two structural states: when the shaft system is in an aligned state, when the whole ship structure is intact and the whole ship is launched, and when the ship is in a free floating state.

[0049] Among them, the principles of finite element modeling include simulating the main hull with plate beam units, simulating the supporting cross beam plate units of the hull structure, and simulating the side piers and slats on the cross beam with spring units, which only bear pressure but not tension. In addition, the finite element calculation needs to consider the weight center of gravity of the structure and support, equipment, and the configuration of the uniform load and concentrated load of the cabin after the whole ship is launched.

[0050] Specifically, through finite element modeling, the structural deformation data of each bearing under the shafting alignment state are shown in Table 1.

[0051] Table 1 Structural deformation data of each bearing under the shaft alignment state

[0052] Location Deformation (x, mm) Deformation (y, mm) Deformation (z, mm) Stern tube rear bearing 0.1 -0.1 -6 Stern tube front bearing 0.2 -0.1 -1.9 7# intermediate bearing 0 0.1 -2.2 6# intermediate bearing -0.1 0.3 -2.5 5# intermediate bearing -0.1 0.1 -2.4 4# intermediate bearing 0 0.2 -2 3# intermediate bearing 0.1 0.2 -2.6 2# intermediate bearing 0 0.3 -2.5 1# intermediate bearing 0 0.3 -2.7 After thrust bearing -0.1 0.2 -2.6 Thrust bearing front -0.1 0.2 -2.4

[0053] Among them, the X coordinate is positive toward the bow and negative toward the stern; the Y coordinate is positive toward the port side and negative toward the starboard side; the Z coordinate is positive upward and negative downward.

[0054] Through finite element modeling, the whole ship structure is intact and after the whole ship is launched, the structural deformation data of each bearing in the two structural states of the ship in the free floating state are shown in Table 2.

[0055] Table 2 Structural deformation data of each bearing after the whole ship is launched

[0056] Location Deformation (x, mm) Deformation (y, mm) Deformation (z, mm) Stern tube rear bearing 16.6 -0.3 26.5 Stern tube front bearing 19.4 -0.2 50.3 7# intermediate bearing 20.9 -0.1 65.8 6# intermediate bearing 20.7 -0.2 77.9 5# intermediate bearing 20.1 0.1 87.5 4# intermediate bearing 20.3 0.2 96.9 3# intermediate bearing 19.3 0.2 105.3 2# intermediate bearing 18.2 0.3 113.1 1# intermediate bearing 17.3 0.3 119.7 After thrust bearing 16.4 0.3 124.4 Thrust bearing front 16.0 0.3 126.3

[0057] Among them, the X coordinate is positive toward the bow and negative toward the stern; the Y coordinate is positive toward the port side and negative toward the starboard side; the Z coordinate is positive upward and negative downward.

[0058] Analyze the data in Table 1 and Table 2. The data in the X direction of the shaft system alignment is not what we are concerned about, but the change data in the Y and Z directions. The shaft system length is about 75 meters, and the maximum deformation in the Y direction is only 0.3mm, which can be ignored. Therefore, only the data change in the Z direction needs to be considered. In other words, only the deformation data of each bearing in the vertical direction needs to be considered. By comparing the structural deformation in the vertical direction under the two states, the reverse deformation can be taken into account in advance when the shaft system is aligned, so as to achieve the purpose of early alignment.

[0059] Step S32, based on the structural deformation data of each bearing under the two structural states and combined with the bearing displacement set in the shaft alignment calculation book, the bearing displacement results required for each bearing during shaft alignment are calculated. Specifically, as shown in Table 3.

[0060] Table 3 Results of bearing displacement required for each bearing during shaft alignment

[0061]

[0062]

[0063] Furthermore, the bearing displacement results required for each bearing during shaft alignment are calculated, including:

[0064] Step S321, calculate the relative deformation data of the whole ship after launching and the state of the shaft system centering. That is, calculate the difference in the structural deformation of each bearing under the two states. The relative deformation of the whole ship after launching and the state of the shaft system centering = the vertical deformation B of the whole ship after launching - the vertical deformation A of the shaft system in the state of illumination centering.

[0065] Step S322, establish a coordinate system, where the horizontal coordinate is the distribution position of each bearing, the vertical coordinate is the relative deformation corresponding to each bearing, and a straight line is drawn in the coordinate system with the line connecting the relative deformation of the front bearing of the stern tube and the rear bearing of the stern tube, and extended to the bow, and the structural deformation of the straight line relative to other bearings is measured and calculated. In other words, the relative deformation is used to model and draw in proportion, and the axis alignment of the axis arrangement method or the straight line method is simulated. The two points of the front and rear bearings of the stern tube are aligned to the bow straight line, and a straight line is drawn with the relative deformation position of the front and rear bearings of the stern tube and extended to the bow, and the structural deformation of the straight line relative to other bearings is measured and calculated.

[0066] Preferably, the transverse coordinate is plotted at a ratio of 1:1, and the longitudinal coordinate is plotted at a ratio of 1:100, so as to facilitate the measurement and calculation of the structural deformation of the straight line relative to other bearings.

[0067] Specifically, modeling and drawing reference Figure 2 .according to Figure 2 , the calculation results of the bearing displacement at this time are shown in Table 4, the unit is mm.

[0068] Table 4 Bearing displacement calculation results

[0069]

[0070] Step S323, optimize the structural deformation of the straight line relative to other bearings to facilitate the construction of the shaft system. As shown in Table 4, the displacement of the thrust front bearing is large, 28mm, which is not conducive to the construction of the shaft system. Therefore, it is necessary to optimize the structural deformation of the straight line relative to other bearings. Optionally, the thrust front bearing can be reduced to a bearing displacement of 8mm, and a new modeling and drawing can be performed based on this. Figure 3 The calculation results of the bearing displacement at this time are shown in Table 5, with the unit being mm.

[0071] Table 5 Calculation results of optimized bearing displacement

[0072]

[0073] Step S324, combining the displacement of each bearing set in the shafting alignment calculation book, obtain the final bearing displacement result. For the optimized bearing displacement calculation result, it is also necessary to consider the displacement of each bearing required by the shafting alignment calculation book. For example, the shafting alignment calculation book requires that the thrust front bearing is 0.43mm lower than the shafting, then the thrust front bearing is considered to be reduced by another 0.43mm in the optimized calculation result, thereby obtaining the following final bearing displacement result. Specifically, as shown in Table 6, the unit is mm.

[0074] Table 6 Final bearing displacement results of each bearing

[0075]

[0076] It should be noted that the bearing displacement needs to be checked by shaft alignment calculation software to ensure that the static load of the bearing and the bending moment of the shaft do not exceed the standard.

[0077] Step S4, manufacture the corresponding eccentric light target 20. The center of the eccentric light target 20 is on the same straight line as the center line of the corresponding bearing 25. The target core marking line 21 of the eccentric light target 20 is higher or lower than the eccentric light target center 22 according to the bearing displacement data. In addition, the manufactured eccentric light target 20 should be marked with corresponding numbers and upper and lower marks to avoid incorrect use during the construction process. Taking the 3# intermediate bearing as an example, since the bearing displacement of the #3 intermediate bearing is "-4.23mm", that is to say, the positioning of the #3 intermediate bearing is required to be 4.23m lower than the axis. The corresponding eccentric light target 20 is made as follows: Figure 5 shown.

[0078] Step S5, reference Figure 4 and Figure 6 , manufacture a corresponding dummy shaft 23, and install corresponding eccentric light targets 20 at both ends of the dummy shaft 23. The axis of the dummy shaft 23 and the center 22 of the eccentric light target are located on the same straight line.

[0079] Step S6, reference Figure 4 , each bearing 25 is placed on a corresponding equipment base 24, and the base 24 is configured to be adjustable in vertical height. Optionally, an adjustment bolt is provided on the base 24, and the base 24 is adjusted in vertical height by adjusting the bolt.

[0080] Step S7, reference Figure 4 , determine the position of the bearing 25 after the shaft system is centered. The dummy shaft 23 is coaxially inserted into the corresponding bearing 25. At this time, the axis of the dummy shaft 23 is coaxial with the center line of the corresponding bearing 25. Since the axis of the dummy shaft 23 and the center 22 of the eccentric light target are located on the same straight line, the center 22 of the eccentric light target is coaxial with the center line of the corresponding bearing 25. By adjusting the position of the bearing 25, the center of the telescope 26 coincides with the target core marking line 21 of the corresponding eccentric light target 20. Since the target core marking line 21 of the eccentric light target 20 is higher or lower than the center 22 of the eccentric light target, when the center of the telescope 26 coincides with the target core marking line 21 of the corresponding eccentric light target 20, the center of the telescope 26 is higher or lower than the center line of the corresponding bearing 25, thereby realizing the positioning of the bearing 25 after the shaft system is centered.

[0081] It should be noted that the stern tube front bearing and the stern tube rear bearing are both set in the stern tube bore. Therefore, when positioning the stern tube front bearing and the stern tube rear bearing, it is only necessary to position the center of the stern tube bore. At this time, the dummy shaft is passed through the stern tube bore, and the positioning of the center of the stern tube bore can be achieved in the same way.

[0082] Step S8, each shaft is installed on the bearing at the determined position, and each shaft is formally installed and tightened using flange bolts.

[0083] After the entire ship structure is installed and the ship is launched, it is necessary to adjust the shaft system load in still water according to the requirements of the shaft system alignment calculation book, and after the shaft system load meets the requirements, the shaft system equipment can be officially and finally installed.

[0084] In summary, the use of telescopes and deflected optical targets has enabled the shafting to be aligned in advance, breaking the original idea that the shafting must be aligned after the entire ship structure is complete. This has made the entire engineering arrangement of ship construction more flexible and shortened the construction period.

[0085] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for centering a ship shaft system, characterized in that: The centering method comprises: Determine a bow reference point and a stern reference point, wherein a line connecting the bow reference point and the stern reference point is a theoretical axis of a ship shaft system; Placing a telescope on one side of the stern reference point close to the stern end, and adjusting the position of the telescope so that the center of the telescope is in the same straight line as the theoretical axis of the ship shaft system; Calculating the bearing displacement data required for each bearing when aligning the shaft system, wherein the bearing displacement data is used to indicate the relative position of the corresponding bearing and the theoretical axis of the ship shaft system; Manufacturing a corresponding decentered light target, wherein the center of the decentered light target is on the same straight line as the center line of the corresponding bearing, and the target core marking line of the decentered light target is higher or lower than the center of the decentered light target according to the bearing displacement data; Manufacturing a corresponding dummy shaft, and installing the corresponding eccentric light targets at both ends of the dummy shaft, respectively, wherein the axis of the dummy shaft and the center of the eccentric light target are located on the same straight line; placing each of the bearings on a corresponding equipment base, wherein the base is configured to be adjustable in vertical height; Determine the position of the bearing after the axis system is centered, coaxially insert the dummy axis on the corresponding bearing, and adjust the position of the bearing so that the center of the telescope coincides with the target core marking line of the corresponding deflected optical target. At this time, the position of the bearing is the position of the bearing after the axis system is centered; Each shaft is correspondingly mounted on the bearings at the determined positions.

2. The ship shafting alignment method according to claim 1, characterized in that: The bearing displacement data required for each bearing when calculating the shaft system alignment includes: Through finite element modeling, the structural deformation data of each bearing in two structural states are calculated: in the state of shaft alignment, in the state of complete ship structure and after the whole ship is launched, and in the state of free floating; Based on the structural deformation data of each bearing under the two structural states and combined with the bearing displacement set in the shafting alignment calculation book, the bearing displacement results required for each bearing when the shafting is aligned are calculated.

3. The ship shaft alignment method according to claim 2, characterized in that: The calculation of the bearing displacement results required for each bearing when the shaft system is aligned includes: Calculate the relative deformation data of the entire ship after launching and the alignment state of the shafting; Establish a coordinate system, in which the horizontal coordinate is the distribution position of each bearing, the vertical coordinate is the relative deformation corresponding to each bearing, and draw a straight line in the coordinate system with the connecting line of the relative deformation of the stern tube front bearing and the stern tube rear bearing, and extend it to the bow, measure and calculate the structural deformation of the straight line relative to other bearings; Optimizing the structural deformation of the straight line relative to other bearings to facilitate shaft system construction; Combined with the displacement of each bearing set in the shafting alignment calculation book, the final bearing displacement result is obtained.

4. The ship shaft alignment method according to claim 3, characterized in that: The horizontal coordinate is plotted at a ratio of 1:1, and the vertical coordinate is plotted at a ratio of 1:

100.

5. The ship shaft alignment method according to claim 1, characterized in that: The step of adjusting the position of the telescope so that the center of the telescope is in the same straight line as the theoretical axis of the ship shaft system includes: A reference target is respectively arranged at the bow reference point and the stern reference point, the target core marking line of the reference target coincides with the center of the reference target, and the target core marking lines of the two reference targets coincide with the bow reference point and the stern reference point respectively; The position of the telescope is adjusted so that the center of the telescope coincides with the target core marking lines of the two reference targets.

6. The ship shaft alignment method according to claim 1, characterized in that: The bow reference point is arranged at the front end of the thrust bearing, and the stern reference point is arranged at the theoretical design center position of the propeller.

7. The ship shafting alignment method according to claim 1, characterized in that: The bow reference point and the stern reference point are acquired according to the average baseline and the shafting arrangement diagram data.

8. The ship shaft alignment method according to claim 1, characterized in that: The centering method also includes marking the completed deflected optical target with corresponding marking numbers and upper and lower markings.

9. The ship shaft alignment method according to claim 2, characterized in that: The principles of finite element modeling include: The main hull is simulated by plate beam units, the supporting beam plate units of the hull structure are simulated by spring units, and the side piers and slats on the beams are simulated by spring units, which only bear pressure but not tension. Finite element calculations need to consider the influence of uniformly distributed loads and concentrated loads on the weight center of gravity of the structure and support, equipment, and the configuration of the cabins after the entire ship is launched.

10. The ship shaft alignment method according to claim 1, characterized in that: The base is provided with an adjusting bolt, and the base can be adjusted in vertical height by the adjusting bolt.

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