Positioning method for allowance-free preassembly of energy-saving guide wheel

Abstract

The invention belongs to the technical field of ocean engineering, and particularly relates to a marine fairing zero-allowance pre-assembly positioning method which comprises the following steps: S1, pre-assembling a tail shaft casting onto a tail shaft section; s2, establishing a tail shaft casting model; s3, generating a fairing design model; s4, the tail shaft casting model and the fairing design model are connected in a matched mode, and interference amount data are obtained; s5, drawing an actual intersecting line between a guide vane of the guide wheel and the tail shaft casting on the guide wheel of the fairing according to the interference amount data; s6, the allowance of the end of the guide vane is cut in advance along the actual intersecting line; and S7, the fairing is hoisted to the tail shaft casting. According to the positioning method provided by the invention, the lapping clearance between the guide vane and the tail shaft casting can be controlled to be 5-12mm, the operation is more convenient, and the construction efficiency and the segmentation completion precision are improved.

Description

Technical Field

[0001] The invention relates to the field of marine engineering technology, and more specifically to a positioning method for energy-saving guide wheels without margin pre-assembly. Background Art

[0002] An energy-saving guide wheel is designed and installed on the tail shaft outlet casting at the rear of a certain type of ship. The main function of the fairing is to guide and converge the water flow when the propeller driven by the main engine rotates, thereby providing a water flow bundling effect for the propeller. Under the same power conditions, the ship's sailing speed is improved to a certain extent, achieving the goal of energy conservation and emission reduction.

[0003] The energy-saving guide wheel is an energy-saving device installed on the tail shaft casting. It is mainly composed of a guide wheel and a guide vane. The installation position and installation angle of each guide vane are different. In the area where different guide vanes are connected to the casting, the intersection curves are different. In the design cutting drawing, a margin of about 50mm is added to the part where the guide vane of the energy-saving guide wheel is connected to the casting, which is used for on-site workers to cut, repair and match when positioning the energy-saving guide wheel.

[0004] When positioning the energy-saving guide wheel, a crane is used to lift it close to the guide wheel. After the surveyor uses a total station to measure and align it, the construction personnel cut and grind the guide vanes of the guide wheel. Due to the large amount of grinding and matching, and each grinding and matching is based on the actual gap and interference between the guide vanes and the casting at 5 different angles, according to construction experience, it is statistically found that the conventional guide wheel positioning process takes about 10 to 12 hours, and it is easy to have a gap error during the excess cutting and matching, which makes it difficult to guarantee the positioning accuracy of the guide wheel. Summary of the invention

[0005] The present invention aims to solve the problems that the cutting and grinding amount is large, the excess cutting and grinding is prone to gap tolerance, the positioning process of the guide wheel is long, and the positioning accuracy of the guide wheel is difficult to ensure, etc., which occur when the energy-saving guide wheel and the tail shaft are assembled in sections in the prior art. The present invention discloses a process method in which a streamlined guide wheel and a guide vane are welded to the tail shaft casting, the three-dimensional measurement function of the total station is used, the function of building a model based on the measured points and lines in CAD is used, the precision software BLOCK analysis and 1-point axis movement, 1-point axis rotation and ECO OTS simulation loading function are used, so as to simulate the loading of the guide wheel model and the casting model, obtain the gap or interference data between the guide wheel and the casting after the simulated loading, draw the actual intersection line between the guide vane and the casting on the guide wheel according to the interference data, and the construction personnel pre-cut the guide vane end margin according to the actual intersection line, and then hoist the guide wheel onto the tail shaft casting for positioning and grinding after precise cutting.

[0006] In order to achieve the above object, the present invention provides a positioning method for energy-saving guide wheels without margin pre-assembly, comprising the following steps:

[0007] S1. Pre-assemble the tail shaft casting onto the tail shaft segmented hull structure;

[0008] S2. Establishing a tail shaft casting model: Establishing the tail shaft casting model includes marking a number of first measuring points on the outer contour surface of the tail shaft casting using a total station, collecting data of the first measuring points, and then establishing the tail shaft casting model using CAD;

[0009] S3. Generate an energy-saving guide wheel design model: Use a total station to mark a number of second measurement points on the guide wheel and guide vane of the energy-saving guide wheel to generate an energy-saving guide wheel design model;

[0010] S4, matching and connecting the tail shaft casting model and the energy-saving guide wheel design model, generating a tail shaft casting and energy-saving guide wheel pre-assembly model, and obtaining interference data;

[0011] The interference data includes a plurality of interference points formed between the guide vane of the energy-saving guide wheel and the tail shaft casting in the tail shaft casting and the guide cover pre-assembly model, and the plurality of interference points are intersections formed between the outer contour of the guide vane (5) and the contour surface of the tail shaft casting;

[0012] S5. Draw an actual intersection line on the guide vane according to the interference data, and cut the remaining amount of the guide vane along the actual intersection line;

[0013] S6. Assemble the cut energy-saving guide wheel onto the tail shaft casting.

[0014] Preferably, in step S2, a plurality of the first measuring points cover the outer contour surface of the tail shaft casting, a plurality of the first measuring points are equidistant points, and a length value of two adjacent first measuring points is 100-200 mm.

[0015] In a preferred manner, in step S4, the matching connection includes establishing a plurality of management points at a plurality of the second measurement points, and matching and connecting the management points with the first measurement points by using the analysis function of the precision software ECO OTS.

[0016] In a preferred manner, in step S4, the position of the tail shaft casting model is adjusted to the theoretical design position of the tail shaft casting on the tail shaft segmented hull structure using the precision software BLOCK before the matching connection, and then the position of the energy-saving guide wheel design model is adjusted to the theoretical design position of the energy-saving guide wheel on the tail shaft casting.

[0017] In a preferred manner, in step S2, taking the center point on the tail end surface of the tail shaft casting as the intersection point, a total station is used to survey the intersection lines of the tail shaft casting and the cross-section of the tail shaft casting, and the intersection lines of the tail shaft casting and the longitudinal section of the tail shaft casting; in step S3, taking the center of the guide wheel as the reference, a total station is used to survey the main reference lines on the guide wheel of the energy-saving guide wheel, the main reference lines include the intersection lines of the guide wheel and the cross-section of the guide wheel, the intersection lines of the guide wheel and the longitudinal section of the guide wheel, and the intersection lines of the guide wheel and the horizontal mid-section of the guide wheel, the intersection points between the main reference lines serve as the main reference line points, and the second measuring point has the main reference line points; in step S4, the cross-section of the guide wheel and the cross-section of the tail shaft casting are arranged on the same vertical plane.

[0018] In a preferred manner, the first measuring point includes a first measuring point on the intersection line of the tail shaft casting and the cross-section of the tail shaft casting and a first measuring point on the intersection line of the tail shaft casting and the longitudinal section of the tail shaft casting. The first measuring point on the intersection line of the tail shaft casting and the cross-section of the tail shaft casting and the first measuring point on the intersection line of the tail shaft casting and the longitudinal section of the tail shaft casting are marked on the tail shaft casting model. The theoretical design position of the energy-saving guide wheel pre-assembled on the tail shaft casting is at the same height as the main reference line point. When matched and connected, the main reference line point is matched and connected with the first measuring point on the intersection line of the tail shaft casting and the cross-section of the tail shaft casting and the first measuring point on the intersection line of the tail shaft casting and the longitudinal section of the tail shaft casting.

[0019] In a preferred manner, the guide vanes are cut to the excess by using a cutting torch.

[0020] In a preferred manner, the second measuring point on the guide vane includes an intersection of the internal reinforcement rib of the guide vane and the guide vane shell plate.

[0021] In a preferred manner, the main reference line points include the guide wheel side reference point of the intersection line of the guide wheel and its cross-section and the intersection line of the guide wheel and its horizontal mid-section, and the guide wheel upper center reference point of the intersection line of the tail shaft casting and its longitudinal section and the intersection line of the guide wheel and its horizontal mid-section.

[0022] The beneficial effects of the present invention are:

[0023] The present invention innovatively realizes high-precision energy-saving guide wheel segmented positioning, tends to be more reasonable, and the matching and measurement are more convenient. It saves crane resources and uses them more reasonably, reduces the scope and time of high-altitude operations, improves positioning accuracy, improves detection efficiency, and reduces shipbuilding costs. This process method was first promoted and applied on the T300K crude oil tanker. So far, it has been promoted and applied on 30 ship types. It has a mature operating process and is very time-effective. On-site positioning is shortened from 10 hours to 3 hours, and the matching gap is controlled between 5 and 12 mm. The gap value fully meets the requirements of ship component welding standards. The present invention rationally optimizes the resource utilization structure, is more convenient to operate, improves construction efficiency, and improves the segmented completion accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the coordinate collection of the contour points of the tail shaft segmented tail ball casting;

[0025] Figure 2 It is a three-dimensional diagram of the energy-saving guide wheel;

[0026] Figure 3 This is a stereoscopic view of the energy-saving guide wheel pre-assembled to the tail shaft segment; Figure 4 This is a schematic diagram of the three-dimensional measurement of the energy-saving guide wheel;

[0027] Figure 5 It is a schematic diagram of the three-dimensional measurement of the tail shaft casting and the tail shaft segment;

[0028] Figure 6 and Figure 7 It is a schematic diagram of the pre-assembly positioning of the energy-saving guide wheel without any allowance.

[0029] In the figure, 1, tail shaft casting; 2, tail shaft segmentation; 3, first measurement point (distributed at the casting coordinate collection point); 4, guide wheel; 5, guide vane; 6, intersection line of the guide wheel and the horizontal mid-section of the guide wheel (transverse reference line on the guide wheel); 7, horizontal reference line on the guide wheel (including the intersection line 701 of the guide wheel and the cross section of the guide wheel, and the intersection line 702 of the guide wheel and the longitudinal section of the guide wheel); 8, second measurement point on the guide vane (intersection point of the internal reinforcement rib of the guide vane and the guide vane shell plate); 10 , horizontal reference line of tail shaft section; 11, longitudinal reference line of tail shaft section; 12, center point of tail shaft casting port; 13, reference point on guide wheel side (one on each side); 14, center reference point on guide wheel; 15, plumb bob; 16, total station; 17, first point; 18, second point; 19, third point; 20, intersection line of tail shaft casting and cross section of tail shaft casting; 21, intersection line of tail shaft casting and longitudinal section of tail shaft casting; 22, main reference line points. DETAILED DESCRIPTION

[0030] The following will provide further explanation in conjunction with embodiments and drawings.

[0031] like Figures 1 to 7 As shown, the method for simulating the tail shaft casting model and the fairing design model includes the following steps:

[0032] S1. Before positioning the energy-saving guide wheel, mark the positions of several first measuring points 3 on the surface of the tail shaft casting 1. The position marks of these first measuring points 3 cover the entire outer contour surface of the tail shaft casting 1, and the length of the position marks of two adjacent first measuring points 3 is 100 mm.

[0033] S2. Use the total station 16 to measure the marked points (first measuring points 3) on the outer contour of the tail shaft casting 1, import the measured data into the computer, read it using the CAD software, mark the position of the first measuring point 3 on the outer contour of the tail shaft casting 1 with three adjacent points connected to form a triangular plane, each triangle forms the smallest unit plane, and all the triangular planes are connected together to form an approximate irregular tail shaft casting surface contour, and render the tail shaft casting model in the CAD software to obtain the tail shaft casting model.

[0034] S3. Use the total station 16 to draw the intersection line of the longitudinal section of the hull and the outer surface of the guide wheel, the intersection line of the center waterline plane of the shaft system and the outer surface of the guide wheel, and the intersection line of the FRX cross section and the outer surface of the guide wheel on the outer surface of the guide wheel 4, so as to determine the main reference line points 22 that need to be measured when positioning the guide wheel 4, and obtain the theoretical value of each reference point through design.

[0035] S4. Use a total station to build a ground sample reference line with the energy-saving guide wheel, measure the three-dimensional coordinates of the main structural points at the end of the guide vane of the energy-saving guide wheel, and import the measured data into the computer; preferably, a cross line formed by the intersection of the hull centerline and the horizontal reference line is used as the ground sample reference line for construction process detection.

[0036] S5. Open the measured tail shaft casting model data in the precision software BLOCK (a precision analysis software that compares the hull model with the measured data, connects the management points on the model with the measured points of the sections, measures the coordinate deviations of the management points, and analyzes the deviations of the section completion data), and use the center of the tail shaft hole of the tail shaft casting as the reference point to adjust the tail casting model data status to be consistent with the design value.

[0037] S6. Read the fairing design model in the precision software BLOCK, establish management points on the energy-saving guide wheel design model, unify the coordinates of the management points and the reference points on the energy-saving guide wheel, and use the analysis function to match and connect the measured data of the tail shaft casting model with the energy-saving guide wheel design model, so that the guide wheel side reference point 13 (1 on each side) and the center reference point 14 on the guide wheel coincide with the theoretical point, and the maximum deviation is less than 2mm; and save it as an analysis file.

[0038] A positioning method for a marine energy-saving guide wheel without margin pre-assembly comprises the following steps:

[0039] S1. Pre-assemble the tail shaft casting 1 to the hull structure of the tail shaft section 2, and use the total station 16 to survey the tail shaft section projection center and the longitudinal section line and the waterline cross-type ground sample line (i.e., the tail shaft section horizontal reference line 10 and the tail shaft section longitudinal reference line 11) based on the fore and aft port centers of the tail shaft casting 1.

[0040] S2. Use the total station 16 to measure the equidistant points (first measuring points 3) marked on the tail shaft casting 1, use the total station 16 to perform three-dimensional coordinate measurement of the equidistant points on the contour of the tail shaft casting, import the measurement data into the computer, open it with CAD software, connect the measured points (equidistant points) with three adjacent points to form a triangle, use a single triangle as a unit section, connect all the unit sections together, use the polygon function of the software to model and render, and save the rendered model file as a DXF file in the CAD program.

[0041] S3. Read the tail shaft casting model file in the precision software BLOCK program. Move and rotate the 1-point axis in the BLOCK program to make the baseline of the tail shaft casting 1 consistent with the design value. Use the 1-point axis movement to make the center point of the end face of the tail shaft casting consistent with its design height and left and right direction. The tail end face of the tail shaft casting 1 is 10 mm as the machining allowance and saved as an analysis file.

[0042] S4. Use a total station to draw the intersection line of the longitudinal section of the hull and the outer surface of the guide wheel, the intersection line of the center waterline plane of the shaft system and the outer surface of the guide wheel, and the intersection line of the FRX cross section and the outer surface of the guide wheel on the outer surface of the guide wheel, so as to determine the reference points that need to be measured when positioning the guide wheel, and obtain the theoretical value of each reference point through design.

[0043] S5. Use a total station to establish a station based on the energy-saving guide wheel ground sample reference line. When establishing the station, the line connecting the first and second points is measured as the centerline of the hull, and the third point is the projection point of the centerline of the tail shaft hole. Then measure the guide wheel side reference point 13 and the guide wheel center reference point 14 drawn on the fairing. Then measure the three-dimensional coordinates of the intersection of the guide vane reinforcement at the end of the fairing and the guide vane outer plate (main structural point 8). Import the measured data into the computer and save it as a DXF file.

[0044] S5. Use the precision software BLOCK to open the saved DXF file of the guide wheel. In the BLOCK analysis function, move to point 1 and rotate the axis at point 1 to make the coordinates of the baseline on the guide wheel the same as the theoretical value, and save it as an analyzed file.

[0045] S6. Open the analysis file of casting 1 in the precision software ECO OTS, and then open the analysis file of the energy-saving guide wheel. In the program, connect the second measurement point of the guide wheel with the first measurement point on the tail shaft casting (i.e., the first measurement point 3 marked on the tail shaft casting). After connecting the first measurement point and the second measurement point, a model interference part and interference amount of the measurement points at different positions of the intersecting line will be generated. Through the software distance measurement, the distance between the measurement point and the point (interference point) can be calculated to calculate the point interference amount at different positions on this intersecting line. The interference amount length is the actual margin of the guide vane at this actual position.

[0046] S7. Based on the interference calculated by the onboard software, use a ruler to mark the actual interference of different structures on the guide vane as the allowance line. The allowance line forms an actual intersection curve. The construction personnel can make precise cuts based on this intersection curve and can pre-cut the allowance for the guide wheel.

[0047] S8. Transfer the cut energy-saving guide wheel to the tail shaft casting.

[0048] The method of the present invention can accurately draw the margin line of the docking port, realize pre-assembly without margin, and perform one-time hoisting and positioning, thereby improving positioning accuracy, increasing construction efficiency, and reducing construction difficulty.

[0049] The present invention innovatively realizes high-precision energy-saving guide wheel segmented positioning, tends to be more reasonable, makes research and measurement more convenient, saves crane resources and makes use of them more reasonably, reduces the scope and time of high-altitude operations, improves positioning accuracy, improves detection efficiency, and reduces shipbuilding costs. This process method was first promoted and applied on the T300K crude oil tanker, and has been promoted and applied on 30 ships so far. It has a mature operating process and is very time-effective, and has been recognized by various processes and shipowners for its technology.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A positioning method for energy-saving guide wheels without margin pre-assembly, characterized in that: The steps include: S1. Pre-assemble the tail shaft casting onto the tail shaft segmented hull structure; S2. Establishing a tail shaft casting model: Establishing the tail shaft casting model includes using a total station (16) to mark a plurality of first measuring points (3) on the outer contour surface of the tail shaft casting, collecting data of the first measuring points (3), and then establishing the tail shaft casting model using CAD; S3, generating an energy-saving guide wheel design model: using a total station (16) to mark a number of second measurement points on the guide wheel (4) and the guide vane (5) of the energy-saving guide wheel to generate an energy-saving guide wheel design model; S4, matching and connecting the tail shaft casting model and the energy-saving guide wheel design model, generating a tail shaft casting and energy-saving guide wheel pre-assembly model, and obtaining interference data; The interference data includes a plurality of interference points formed by connecting the guide vane (5) of the energy-saving guide wheel and the tail shaft casting in the pre-assembled model of the tail shaft casting and the energy-saving guide wheel and forming a mounting intersection line, wherein the mounting intersection line is used as a boundary line for the margin cutting; the plurality of interference points are intersection points formed by the outer contour of the guide vane (5) and the contour surface of the tail shaft casting; S5, surveying and drawing an actual intersection line on the guide vane (5) according to the interference data, and cutting the excess of the guide vane along the actual intersection line; S6. Assemble the cut energy-saving guide wheel onto the tail shaft casting.

2. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 1 is characterized in that: In step S2, a plurality of the first measuring points (3) cover the outer contour surface of the tail shaft casting, the plurality of the first measuring points (3) are equidistant points, and the extension value of two adjacent first measuring points (3) is 100 to 200 mm.

3. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 1 is characterized in that: In step S4, the matching connection includes establishing a plurality of management points at a plurality of the second measuring points, and matching and connecting the management points with the first measuring points (3) by using the analysis function of the precision software ECO OTS.

4. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 1 is characterized in that: In step S4, before the matching connection, the precision software BLOCK is used to adjust the position of the tail shaft casting model to the theoretical design position of the tail shaft casting on the tail shaft segmented hull structure, and then the position of the energy-saving guide wheel design model is adjusted to the theoretical design position of the energy-saving guide wheel on the tail shaft casting.

5. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 4 is characterized in that: In step S2, the center point (12) on the tail end surface of the tail shaft casting is used as the intersection point, and the total station (16) is used to survey the intersection line (20) of the tail shaft casting and the cross section of the tail shaft casting, and the intersection line (21) of the tail shaft casting and the longitudinal section of the tail shaft casting; in step S3, the center of the guide wheel is used as the reference, and the total station (16) is used to survey the main reference line (7) on the guide wheel (4) of the energy-saving guide wheel. The main reference line (7) includes the intersection line (701) of the guide wheel and the guide wheel cross section on the guide wheel (4), the intersection line (702) of the guide wheel and the guide wheel longitudinal section on the guide wheel, and the intersection line (6) of the guide wheel and the guide wheel horizontal mid section on the guide wheel. The intersection point between the main reference lines (7) is used as the main reference line point (22), and the second measuring point has the main reference line point (22); in step S4, the cross section of the guide wheel and the cross section of the tail shaft casting are arranged on the same vertical plane.

6. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 5 is characterized in that: The first measuring point (3) includes a first measuring point on the intersection line (20) of the tail shaft casting and the cross section of the tail shaft casting and a first measuring point on the intersection line (21) of the tail shaft casting and the longitudinal section of the tail shaft casting. The first measuring point on the intersection line (20) of the tail shaft casting and the cross section of the tail shaft casting and the first measuring point on the intersection line (21) of the tail shaft casting and the longitudinal section of the tail shaft casting are marked on the tail shaft casting model. The theoretical design position of the energy-saving guide wheel pre-assembled on the tail shaft casting is at the same height as the main reference line point (22). When matched and connected, the main reference line point (22) is matched and connected with the first measuring point on the intersection line (20) of the tail shaft casting and the cross section of the tail shaft casting and the first measuring point on the intersection line (21) of the tail shaft casting and the longitudinal section of the tail shaft casting.

7. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 1 is characterized in that: The guide vane (5) is cut to the required size using a cutting torch.

8. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 1 is characterized in that: The second measuring point on the guide vane (5) includes an intersection point (8) between the internal reinforcement rib of the guide vane and the guide vane shell plate.

9. The positioning method for energy-saving guide wheels without margin pre-assembly according to claim 6, characterized in that: The main reference line points (22) include the intersection of the guide wheel and the guide wheel cross section (701) and the intersection of the guide wheel and the guide wheel horizontal mid-section (6), the guide wheel side reference point (13), and the intersection of the tail shaft casting and the tail shaft casting longitudinal section (702) and the intersection of the guide wheel and the guide wheel horizontal mid-section (6), the guide wheel upper center reference point (14).

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