Tail shaft tube PE precision control method

Abstract

The invention discloses a PE precision control method for a tail shaft tube, relates to the technical field of ship building operation, and solves the problem that the precision of the tail shaft tube is difficult to guarantee due to heavy sections, welding shrinkage and the like in the prior art. Comprising the following steps: data measurement: according to the positions of a base point and the center of the stern end of a stern tube, measuring the left-right deviation of the center of the bow end of the stern tube, and measuring the horizontal height difference of the base point, the center of the bow end of the stern tube and the center of the stern end of the stern tube; the positions of the segments are adjusted, so that the measured data reach the precision requirement range, and the horizontal heights of the base point, the center of the bow end of the tail shaft tube and the center of the stern end of the tail shaft tube are positioned by applying reversible deformation; and after all the measured data meet the precision requirement, positioned welding construction is sequentially carried out on the deck, the inner bottom plate and the outer plate. Through the new process method, the precision deviation of the tail shaft tube is controlled and reduced in the operation process, and the effects that the mounting precision of the tail shaft tube is guaranteed, and the subsequent shaft core penetration requirement is met are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of shipbuilding operations, and in particular to a stern tube PE precision control method. Background Art

[0002] The stern tube (BOSS) is a critical component of a ship's rudder and shaft system, requiring high precision. Using a process without secondary boring, the stern tube's installation accuracy impacts the subsequent installation of the primary and secondary boreholes, as well as the main engine, stern shaft, and rudder. During the finalization phase, the stern tube's AP1 and APU sections are integrated with the aft engine room section (PE). (PE refers to the assembly of hull sections, the process of joining multiple sections into a large, integrated section). Positioning, assembly, and welding are then performed. During this process, due to the heavy weight of the sections and welding shrinkage, the relative positions of the base point, the BOSS table (the bow end of the stern tube), and the BOSS bude (the aft end of the stern tube) can deviate significantly, making accuracy difficult to guarantee. Summary of the Invention

[0003] The purpose of the present invention is to provide a tail tube PE precision control method, which controls and reduces the precision deviation of the tail tube during operation, ensures the installation accuracy of the tail tube, and meets the subsequent shaft core penetration requirements.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: A method for controlling the PE precision of a tail tube comprises the following steps: Data measurement, including measuring the left and right deviation of the stern tube bow center based on the position of the base point and the stern tube stern center, and measuring the horizontal height difference between the base point, the stern tube bow center, and the stern tube stern center; Adjust the segment positions so that the above measured data meet the accuracy requirements. The horizontal heights of the base point, the center of the bow end of the stern tube, and the center of the stern end of the stern tube are positioned by applying anti-deformation. After all the above-mentioned measured data meet the accuracy requirements, positioning welding construction is carried out on the deck, inner bottom plate and outer plate in sequence.

[0005] Furthermore, the measurement data also includes measuring the length from the bow end of the stern tube to the base point.

[0006] Furthermore, during the tack welding process, tack welding is performed symmetrically on both sides of the outer plate from bottom to top at the same time.

[0007] Furthermore, in the measurement data, the left and right deviation of the center of the bow end of the stern tube is required to be ±1 mm.

[0008] Furthermore, the base point, the center of the bow end of the tail tube, and the center of the tail end of the tail tube are positioned by applying reverse deformation according to the requirements of A, B, and C respectively. <B<+3,-5<C<-3。

[0009] Furthermore, B=+2, C=-4.

[0010] Furthermore, during the positioning welding construction process, the welding part is divided into N sections according to the welding sequence, and the welding time interval of each section is clearly defined during welding. The welding is carried out in sequence and time periods to ensure symmetrical welding.

[0011] Furthermore, during the positioning welding construction process, if the left and right deviations of the bow end of the tail shaft tube exceed the preset value, the operation rhythm of the left and right sides is adjusted according to the deviation data. The side with too fast speed is paused and the other side continues welding. After the deviation data returns to normal, the left and right sides are welded simultaneously.

[0012] Furthermore, the preset value of the left-right deviation of the bow end of the stern tube is 1.5 mm.

[0013] In summary, the present invention has the following beneficial effects: The existing technology has the following pain points: uncontrollable welding shrinkage, insufficient pre-deformation compensation, chaotic assembly welding sequence, and lagging detection methods. However, this application ensures the accuracy of the tail shaft data after welding by applying pre-deformation, and reduces the tail shaft data accuracy deviation caused by welding shrinkage by controlling the welding sequence. Through systematic pre-deformation application, dynamic compensation technology and welding sequence optimization, the problem of stern tube accuracy deviation caused by welding shrinkage of the stern frame of large-tonnage ships is solved, and the accuracy control of the ship shaft system installation is achieved. It can be applied to the accuracy assurance of the stern tube PE in the construction of various types of ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of each welding segment in a method for controlling the PE precision of a tail tube according to the present invention; Figure 2 This is a schematic diagram of the specific structure of the tail tube core in a tail tube PE precision control method of the present invention; Figure 3 This is a simplified schematic diagram of the horizontal height deviation of the tail tube axis in a tail tube PE precision control method of the present invention; Figure 4 It is a schematic diagram of the welding sequence in a tail tube PE precision control method of the present invention. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. This embodiment does not constitute a limitation of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0016] A method for controlling the PE precision of the tail tube, such as Figure 1 As shown, this embodiment is applied to the stern tube PE operation during the construction of ships such as 16000TEU (Twenty-foot Equivalent Unit, a measurement method based on a 20-foot long international standard container). In the construction of large container ships of 16,000 TEU and above, the stern tube system is a core component of the ship's propulsion system. Its installation accuracy directly affects the centerline alignment of the shafting (which must meet the IT6 standard) and the ship's navigation performance. This embodiment achieves precision control of the assembly and welding of the stern tube of 16,000 TEU container ships. Specifically, it involves an optimization solution for the positioning, assembly, and welding operations of the AP1*APU segment after the PE is fixed on the 16,000 TEU ship.

[0017] like Figure 1 As shown, a new process is adopted in the stern tube PE precision control method, which specifically includes the following steps: Step S10: Before positioning the AP1*APU segment on the PE, the welding of the 3E3 segment and the 4S4C segment on the outer side (the outer side refers to the bow direction, or the front) must be completed or substantially completed; Confirm that the level of the BN3 and BN4 sections in the inner bottom plating is level (level refers to the bow direction, level refers to the stern direction) to ensure that the shaft core is level and parallel to the inner bottom plating (the shaft core is the center of the stern tube); Then carry out the PE operation of AP1*APU segment and temporarily weld it on the deck (the tail tube and AP1*APU segment have been integrated in the previous process, Figure 1 The outer plate seam marked in red is the welding position to be controlled, which is the same on both sides). Make sure that the lower wooden support is in good condition to ensure the stability of the section and prevent tipping accidents.

[0018] Step S20, data measurement, This involves first locating the base point and the center of the stern tube's stern end (BOSS Friend). This involves drawing a piano wire from the base point to the center of the stern tube's stern end to measure the left-right deviation of the stern tube's bow end (BOSS Friend). This involves measuring the horizontal height difference between the base point, the center of the stern tube's bow end, and the center of the stern tube's stern end, and then measuring the length from the stern tube's bow end to the base point. (BOSS is the abbreviation for stern tube; Friend refers to the bow direction, or front of the ship; and Friend refers to the stern direction, or back of the ship.) Adjust the position of the AP1*APU segment to make the above measurement data reach the accuracy requirement range; among which, as Figure 2 and Figure 3 shown, the horizontal heights of the base point, the center of the forward end of the stern tube, and the center of the aft end of the stern tube are positioned by applying reverse deformation; Specifically, the left-right deviation requirement of the center of the forward end of the stern tube (BOSS table) is ±1 mm, and the horizontal heights of the base point, the center of the forward end of the stern tube, and the center of the aft end of the stern tube are positioned by applying reverse deformation according to the requirements of A, B, and C respectively, A, B, and C can be corrected through the data before and after deformation, and then through estimation and long-term tracking summary. It can also be obtained by means of curve fitting or estimation algorithms, etc. Among them, point A is the base point, and B and C are horizontally referenced to point A. Therefore, in this embodiment, when A = 0, +1 < B < +3, -5 < C < -3 (in some embodiments, it is preferably A = 0, B = +2, C = -4); The application of reverse deformation is to cope with subsequent welding shrinkage, because it is inevitable that welding will cause shrinkage. The welding sequence of the outer plate is from bottom to top, and the upper part of the weld will shrink more than the lower part. After welding is completed, the aft end of the stern tube has an upward trend. For example, the original C of -4 will become -3 or even -2, and finally meet the requirements of the shaft core data for subsequent in-dock operations.

[0019] Step S30, as Figure 4 shown, after all the measurement data in step S20 meet the requirements, tack welding construction is carried out on the deck ( Figure 4 the first sequence in Figure 4 ), the inner bottom plate ( Figure 4 the second sequence in ), and the outer plate ( the third and fourth sequences in ), in sequence. Among them, the two sides of the outer plate are tack welded from bottom to top (the third and fourth sequences), symmetrically at the same time, and the tack welding spacing is about 2.5 meters; after tack welding is completed, data measurement and recording are carried out the next day; Specifically, during the tack welding construction process, the operation sequence requirement is from bottom to top and symmetric left and right. The welding part is divided into N segments according to the welding sequence. When welding, the welding time interval of each segment is clearly defined, and welding is carried out in sequence and time periods to ensure symmetric welding; During the assembly and welding operation process, measure the data before work every morning. Due to welding shrinkage, it is normal for the measurement data to have a little fluctuation during the welding process. It is only necessary to ensure symmetric operation on both sides of P / S (Port left side, Starboard right side);However, if the left-right deviation of the bow end of the stern tube exceeds a preset value (in this embodiment, the preset value is 1.5mm), the P / S operation rhythm is adjusted based on this deviation data. The side with the excessive speed is paused while welding continues on the other side. Once the deviation data returns to normal (in this embodiment, the normal left-right deviation is 1mm, which can also be set to any value between 0 and 1.5mm), simultaneous welding of both sides is resumed to ensure that the accuracy data meets the requirements. The first half of the welding operation has a particularly significant impact on accuracy and requires strict control. Therefore, in this embodiment, the control of the first half of the tack welding process is more stringent than the second half.

[0020] Step S40: After all welding is completed, the data is measured and recorded again; The data measurement at all stages must be performed without sunlight, and no other operations with large vibrations are in progress in the entire PE unit to ensure the accuracy of the measurement data.

[0021] This embodiment ensures the accuracy of the tail shaft data after welding by applying pre-deformation, and reduces the tail shaft data accuracy deviation caused by welding shrinkage by controlling the welding sequence. It is suitable for use in the positioning, assembly, and welding operations of the tail shaft tube segments during the set-up stage. It is suitable for ensuring the accuracy of the tail shaft tube PE in the construction of various types of ships, and is particularly suitable for the construction of large container ships of 16,000 TEU and above.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The technical content and technical features of the present invention have been disclosed above. However, those skilled in the art may still make various substitutions and modifications based on the teachings and disclosures of the present invention without departing from the spirit of the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the technical solution of the present invention. Therefore, the scope of protection of the present invention should not be limited to the contents disclosed in the embodiments, but should include various substitutions and modifications that do not depart from the present invention and are covered by the claims of this patent application.

Claims

1. A method for controlling the precision of PE of a tail tube, characterized by: The following steps are included: Data measurement, including measuring the left and right deviation of the stern tube bow center based on the position of the base point and the stern tube stern center, and measuring the horizontal height difference between the base point, the stern tube bow center, and the stern tube stern center; Adjust the segment positions so that the above measured data meet the accuracy requirements. The horizontal heights of the base point, the center of the bow end of the stern tube, and the center of the stern end of the stern tube are positioned by applying anti-deformation. After all the above-mentioned measured data meet the accuracy requirements, positioning welding construction is carried out on the deck, inner bottom plate and outer plate in sequence.

2. A stern tube PE precision control method according to claim 1, characterized in that: The measurement data also includes the length from the bow end of the stern tube to the base point.

3. The method for controlling the PE precision of a stern tube according to claim 1, characterized in that: During the tack welding process, tack welding is performed symmetrically on both sides of the outer plate from bottom to top at the same time.

4. The method for controlling the PE precision of a stern tube according to claim 1, characterized in that: In the measurement data, the left and right deviation of the center of the bow end of the stern tube is required to be ±1mm.

5. A stern tube PE precision control method according to claim 3 or 4, characterized in that: The base point, the center of the bow end of the tail tube, and the center of the tail end of the tail tube are positioned by applying reverse deformation according to the requirements of A, B, and C respectively. <B<+3,-5<C<-3。 6. The method for controlling the PE precision of a stern tube according to claim 5, characterized in that: B=+2, C=-4.

7. The method for controlling the PE precision of a stern tube according to claim 1, characterized in that: During the positioning welding construction process, the welding part is divided into N sections according to the welding sequence. The welding time interval of each section is clearly defined during welding. The welding is carried out in sequence and time periods to ensure symmetrical welding.

8. A stern tube PE precision control method according to claim 1 or 7, characterized in that: During the positioning welding construction process, if the left and right deviations of the bow end of the tail tube exceed the preset value, the operation rhythm of the left and right sides is adjusted according to the deviation data. The side with too fast speed is paused and the welding of the other side is continued. After the deviation data is normal, the left and right sides are welded simultaneously.

9. The method for controlling the PE precision of a stern tube according to claim 8, characterized in that: The preset value of the left-right deviation of the bow end of the stern tube is 1.5 mm.

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