Device and method for maintaining main bearing cover in high-power marine diesel engine room

Abstract

The invention provides a device and method for maintaining a main bearing cover in a high-power marine diesel engine cabin, and belongs to the technical field of marine diesel engine maintenance. After the combined tool is designed, a triangular plate type complete machine lifting appliance capable of lifting a complete machine in a narrow space in a cabin, a four-point supporting tool for fixing a diesel engine, a device for disassembling and assembling an oil pan and protecting cleanliness, and a machine body opening device for disassembling and assembling a main bearing cover can be realized; the problems that when the main bearing cover is maintained in a cabin, the space is narrow, a ship shakes and is unstable in water, and the cleanliness is not high, so that the assembling technical difficulty of the main bearing cover is large are solved. Based on the device, a set of method for maintaining the main bearing cover in the cabin is formed, and the technical difficulty of maintaining the main bearing cover in the diesel engine cabin is effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of marine diesel engine maintenance, and in particular relates to a device and a method for repairing a main bearing cap in a high-power marine diesel engine room. Background Art

[0002] The main bearing cap is one of the key parts of a marine diesel engine. It is installed on the main bearing support cross plate of the fuselage and serves as half of the main bearing seat. After being assembled with the fuselage, it is processed to form a high-precision main bearing hole for the crankshaft to operate.

[0003] After a certain type of high-power marine diesel engine 1 (5.5m long × 1.8m wide × 2.9m high, V-type 20 cylinders, 11 gear main bearing cover model) was delivered to the user, it was found that the strength of the front and rear gear main bearing covers (KS, KGS) (360mm wide, 10kg heavy) did not meet the requirements of the drawings. After long-term operation, deformation and looseness will occur, which is very likely to cause major quality accidents such as burning bearings and shaft seizure, resulting in machine damage and death. Therefore, it is urgent to repair the main shaft cover in the narrow space in the engine room 3 (see Figure 1-3 ). Through analysis, the following difficulties exist in the maintenance of the main bearing cap in the cabin:

[0004] 1) The main bearing cap 1-3 is the first part to be assembled in the diesel engine, and is an integrally bored part with the fuselage 1-1. It is the most basic single-mounted fixing part of the diesel engine. The conventional operation requires breaking the compartment 3-3 to fish out the diesel engine and then returning it to the factory for repair. The cost of breaking the compartment, returning the diesel engine to the factory for transportation, and repairing it is huge, and the repair cost is about tens of millions.

[0005] 2) The diesel engine is located in the bottom cabin of the hull. The relevant cabin on the top needs to be cut to remove the whole engine. The diesel engine is lifted out by a large-tonnage crane from the outside and placed inside the soundproof box 2 in the cabin (the maintenance space is about 0.5m). The oil, water, gas, electricity and other systems are involved in complex engineering, with huge engineering workload, complicated operation and high difficulty coefficient.

[0006] 3) The conventional factory repair method requires the diesel engine to be completely disassembled (the diesel engine is assembled from more than 10,000 parts), the fuselage 1-1 is removed, the new main bearing cover 1-3 is installed, the diesel engine 1 is reassembled, and after the bench test is passed, it is returned to the cabin for positioning, alignment, and restoration of the cabin systems. A large number of disassembly and assembly tools and maintenance sites are required. However, the space in the cabin is small, construction is difficult, and cleanliness control is difficult, so the conventional whole-machine disassembly and maintenance plan cannot be used in the cabin.

[0007] 4) The diesel engine is heavy (greater than 20 tons). The lifting beam type whole machine hoist (3m lifting space) of this model is small in the cabin (1.5m lifting space). This type of hoist cannot be installed and used, making it difficult to lift the diesel engine.

[0008] 5) The main bearing cover 1-3 and the fuselage 1-1 are interference fit (interference 0.01-0.06mm), and the fuselage needs to be opened (0.1-0.5mm) during disassembly and assembly. The main bearing cover is fastened to the fuselage 1-1 by a set of main bearing bolts 1-4 and a set of transverse bolts 1-6. The main bearing bolts are high-strength bolts (elongation 1-1.05mm), and the transverse bolts are tightened by torque plus angle, which has high tightening requirements and is difficult to assemble.

[0009] 6) Normal maintenance should be carried out by boring the fuselage 1-1 and the new main bearing cap to meet the coaxiality of adjacent gears ≤0.04mm and the coaxiality of each gear ≤0.2mm. Before installing the crankshaft, test-install the main bearing cap with bushings and measure the main bearing aperture size and lateral ovality ≤0.07mm to ensure a suitable oil gap with the crankshaft to meet the lubrication and heat dissipation of the crankshaft. The assembly precision is high, which makes maintenance difficult.

[0010] Through investigation, there are three existing maintenance solutions:

[0011] Plan 1: After the diesel engine is fished out of the cabin, it is returned to the factory to repair the main bearing cap. The factory repair method requires the diesel engine to be completely disassembled, the fuselage to be removed, new main bearing caps to be installed, the diesel engine to be reinstalled, and the bench test to be passed before it is returned to the cabin for positioning, alignment, restoration of the cabin systems, and repair welding of the broken cabin. This process requires a large number of disassembly and assembly tools and repair sites. Currently, there are more than 20 cases of this type of aircraft being returned to the factory for repair and replacement of main bearing caps of various gears.

[0012] Solution 2: A method for replacing a main engine crankshaft of a ship, including setting a lifting point, confirming a lifting position, opening a process hole, presetting a bracket, removing accessories, lifting the crankshaft and the frame at the same time, lowering the crankshaft to the preset bracket, translating the crankshaft, lifting the crankshaft again, moving the crankshaft forward, slowly turning the crankshaft, the crankshaft exiting the process hole, the new crankshaft entering the cabin in the reverse process, and installing and positioning.

[0013] Solution 3: A method and device for assembling a crankshaft with a straight fuselage, in which the crankshaft is fixed, the fuselage is lifted and lowered, and the crankshaft is pre-positioned; the fuselage is fixed, the crankshaft is raised, and the fuselage is finally positioned and installed. This method is widely used in the crankshaft assembly process in the production of medium-speed and high-power diesel engines.

[0014] The above three solutions have the following defects:

[0015] Solution 1: This solution is suitable for diesel engines whose main bearing caps of all gears need to be replaced and repaired. The amount of work required to repair a damaged engine is huge, with a repair cost of tens of millions for each engine. The repair scenes are frequently switched, and many projects and units are involved. The scope of the incident is large, and there are various uncontrollable potential risks.

[0016] Option 2: This option is suitable for replacement inside the crankshaft compartment. The focus is on the description of the hoisting method of the entire engine and crankshaft inside the compartment. There is ample space inside the compartment and lifting is simple. The technical difficulties in repairing the main bearing cover mentioned above are not explained. The maintenance process method of the diesel engine itself is unclear, and the overall option is relatively rough.

[0017] Option 3: This option is applicable to the normal process of installing the crankshaft of a diesel engine, and focuses on a crankshaft installation option when the fuselage is upright. It fails to explain the technical difficulties in repairing the proposed bearing cover, fails to identify the complexity and difficulty of in-cabin maintenance, and cannot solve the technical difficulties in repairing the main bearing cover involved in this case.

[0018] In summary, the maintenance of the main bearing cap in the cabin of this type of diesel engine is complex, technically demanding, and difficult to construct. The existing related maintenance process solutions all have defects and cannot effectively guide the maintenance of the main bearing cap in the cabin of this type of diesel engine. In order to solve the above-mentioned problem of in-cabin maintenance of the main bearing cap, reduce the difficulty and complexity of maintenance construction, eliminate maintenance risks, significantly reduce maintenance costs, and control the scope of the impact of the event itself, it is necessary to design a new device and method for in-cabin maintenance of the main bearing cap of a high-power marine diesel engine. Summary of the invention

[0019] The technical problem solved by the present invention is as follows: A device and method for repairing the main bearing cap in a high-power marine diesel engine cabin are provided. The present invention aims to solve the problems of the difficulty in assembling the main bearing cap due to the small space in the cabin, the unstable shaking of the ship in water, and the low cleanliness, so as to realize efficient and high-quality maintenance in the main bearing cap cabin of the diesel engine.

[0020] In order to achieve the above object, the technical solution adopted by the present invention is:

[0021] A device for repairing a main bearing cap in a cabin of a high-power marine diesel engine, comprising a combined tool for repairing the main bearing cap in the cabin, the combined tool comprising a triangular plate type whole machine lifting device, a supporting tool, an oil pan disassembly and assembly and cleanliness protection device, and a fuselage propping device;

[0022] The triangular plate type whole machine hoist is provided with two sets and is used to be installed on the output end and free end of the diesel engine respectively. The upper end of the triangular plate type whole machine hoist is fastened to the whole machine hoist point fixed on the third deck of the cabin through a manual hoist;

[0023] The supporting fixtures are provided with four sets and are respectively fixed at the four corners of the bottom of the diesel engine which is hoisted a certain distance to support the diesel engine;

[0024] The oil pan disassembly and cleanliness protection device protects the oil pan from disassembly and cleanliness;

[0025] The fuselage propping device is installed at the adjacent fuselage openings of the two main bearing caps at the output end and the free end of the diesel engine and is used to prop the fuselage open.

[0026] To further limit the above technical solution, the triangular plate type whole machine hoist includes a triangular hanging plate, and the two lower corners of the triangular hanging plate are connected to special steel ropes through D-type shackles 1, and the lower end of the special steel rope is used to be connected and fastened with the lifting eye bolts on the diesel engine, and the upper corner of the triangular hanging plate is connected to the manual hoist through the D-type shackle 2, and the manual hoist is fastened to the whole machine lifting point welded on the third deck.

[0027] As a further limitation of the above technical solution, the distance between the two special steel ropes at the lower part of the triangular hanging plate is determined according to the lifting distance L1 of the lifting eye bolts on the diesel engine.

[0028] To further limit the above technical solution, the structure of the supporting tooling includes two vertical plates symmetrically fixed between the bottom plate and the top plate, and a reinforcing plate fixed between the two vertical plates; the bottom plate is used to be fastened to the I-beam on the diesel engine, and the top plate is used to be fastened to the supporting bracket on the diesel engine.

[0029] To further limit the above technical solution, the oil pan disassembly and cleanliness protection device includes a plastic sheet for laying on the oil pan, sleepers for padding under the oil pan, and a wooden board for laying on the I-beam at the output end and free end of the diesel engine to be used as a maintenance work platform.

[0030] To further limit the above technical solution, the fuselage expansion device includes a left-handed stud and a right-handed stud for supporting the opening on the A and B sides of the fuselage, and an expansion nut threadedly connecting the left-handed stud and the right-handed stud.

[0031] A method for repairing a main bearing cap in a cabin of a high-power marine diesel engine, based on a combined tool for repairing a main bearing cap in a cabin, the method comprising the following steps:

[0032] Step 1): Dismantling of peripheral systems: disconnect the oil, water, gas and electricity connections around the diesel engine, and remove all systems and devices in the engine room that affect the maintenance of the main bearing cap of the diesel engine;

[0033] Step 2): Box body removal: remove the sound insulation box body around the diesel engine and disconnect the pipeline between the sound insulation box body and the diesel engine;

[0034] Step 3): Preparation work before diesel engine lifting: confirm the whole engine lifting point on the third deck, install the triangular plate whole engine lifting device and manual hoist on the diesel engine lifting eye bolt, and adjust the height of the manual hoist to effectively connect it with the whole engine lifting point;

[0035] Step 4): Remove the vibration isolator and lift the diesel engine: remove the rubber vibration isolator between the support bracket and the I-beam at the bottom of the diesel engine, and use a manual hoist to slowly and steadily lift the diesel engine to the set height L3; install the support tooling between the support bracket and the I-beam of the diesel engine, and place the sling and sleepers under the oil pan;

[0036] Step 5): Remove the oil pan: Loosen the oil pan bolts, remove the connecting oil pipe from the oil pan to the transmission case, use a sling to slowly move the oil pan out from between the hydraulic coupler and the transmission case at an angle of α, and place it on the sleeper; cover the oil pan with a whole piece of clean plastic sheet, and lay plywood on the plastic sheet for protection; lay wooden boards under the main bearing cover that needs to be replaced for the working platform;

[0037] Step 6): Remove the main bearing cap: remove the front and rear output end main bearing caps and the free end main bearing caps, loosen the transverse tension bolts, and use the fuselage opening device to open the fuselage; use a hydraulic tensioner to remove the main bearing cap nuts, and the hydraulic tensioner manual pump pressurizes the pressure from the set pressure to check whether the nuts can be loosened by increasing 5MPa each time, pay attention to the changes in the control oil pressure and the length of the main bearing studs, remove the main bearing caps and make good markings and protection;

[0038] Step 7): Copy a new main bearing cap: Use the method of precise 3D scanning and mapping to fit the 3D digital model of the faulty main bearing cap, form a manufacturing drawing, and process a new main bearing cap with controllable accuracy and up to standard quality;

[0039] Step 8): Install the new main bearing cap: Use the fuselage opening device to open the fuselage, reinstall the corresponding new main bearing cap to the corresponding position of the diesel engine according to the identification mark, and tighten the transverse tightening bolts and main bearing cap nuts;

[0040] Step 9): Reinstall the oil pan: remove the wooden board and plastic sheet on the oil pan, use the pre-installed sling under the oil pan to lift the oil pan steadily, tilt the oil pan to avoid the hydraulic coupler, install the oil pan into the fuselage, and tighten the oil pan bolts;

[0041] Step 10): Reinstall the vibration isolator and place the diesel engine: remove the sleepers and slings under the oil pan, remove the supporting tooling, reinstall the rubber vibration isolator, and use a manual hoist to slowly lower the diesel engine so that the supporting bracket, rubber vibration isolator, and I-beam are connected and tightened;

[0042] Step 11): Box body restoration: restore the soundproof box body around the diesel engine and connect the pipeline between the box body and the diesel engine;

[0043] Step 12): Peripheral system recovery: Restore the oil, water, gas and electricity connections around the diesel engine, and reinstall all systems and devices in the engine room that affect the maintenance of the main bearing cap of the diesel engine.

[0044] As a further limitation to the above technical solution, the lifting height L3 of the diesel engine is ≥800 mm, and the lifting height L3 of the diesel engine is less than the distance L2 from the diesel engine to the third deck.

[0045] As a further limitation of the above technical solution, the height of the supporting tooling is determined according to the lifting height L3 of the diesel engine.

[0046] The advantages of the present invention compared with the prior art are:

[0047] 1. The combined tool for in-cabin maintenance of the main bearing cap provided by this scheme has a reasonable design, low material cost, low manufacturing difficulty, easy use, and high safety factor. It has a high reference significance for disassembly, assembly, lifting, cleanliness and safety protection in a narrow space in the cabin. It can be used in combination according to the maintenance conditions in the cabin, and is suitable for various major in-cabin maintenance operations of marine high-power diesel engines, and is easy to promote;

[0048] 1) This combined tool has a reasonable structural design, low-cost materials, low manufacturing difficulty, easy use, and high safety factor. It can meet the safety operation requirements of lifting, disassembly, and protection when repairing the main bearing cover of the diesel engine in the cabin. Through combined application, it is suitable for various types of major maintenance operations of diesel engines in the cabin, easy to operate, and strong in promotion;

[0049] 2) The triangular plate type integral lifting device has a simple structure and occupies a small space (L2≤1.5m), which is convenient for lifting the whole machine in the narrow space in the cabin. The triangular lifting plate is preferably cut and formed from 45GB / T699 steel plate, and three lifting holes for installing the shackle are drilled. The lifting plate is subjected to a 15t hanging weight test. The material cost is low, the processing difficulty is low, the transportation and use are convenient, safe and reliable, and it can be adjusted according to the center distance L1 of the diesel engine eye bolt, and has strong adaptability;

[0050] 3) The 4-point support fixture for fixing the diesel engine is preferably made of 5 independent Q235A carbon steel plates, which are cut, processed and welded, with reserved weld grooves and full-melt arc welding. The structure has high strength and reliable welding. The vertical plate can be adjusted according to the lifting height L3 to adapt to the diesel engine support of different heights and create an operating space that meets the maintenance of the main bearing cap;

[0051] 4) Used for oil pan disassembly and cleanliness protection device, low-cost wood, plastic and other materials are selected, combined design, meet the protection, lifting and other operational requirements, high practicality, easy to make and select;

[0052] 5) The left and right threads of the body expansion device are matched when the main bearing cap is disassembled and assembled. The left side is designed as a left-hand thread connection, and the right side is designed as a right-hand thread connection, which is exquisitely designed;

[0053] 2. This solution provides a method for repairing the main bearing cap in the cabin of a high-power marine diesel engine. After designing a combined tool for repairing the main bearing cap in the cabin, a triangular plate lifting device for lifting the whole machine in the narrow space in the cabin, a 4-point support tooling for fixing the diesel engine, a device for disassembling and assembling the oil pan and a cleanliness protection device, and a device for opening the fuselage and tightening the bolts when disassembling and assembling the main bearing cap can be used to solve the problems of the narrow space for repairing the main bearing cap in the cabin, the unstable shaking of the ship in the water, and the difficulty in assembling the main bearing cap due to low cleanliness.

[0054] 3. The method for repairing the main bearing cap in the cabin of the present invention has a clear and reasonable process and is easy to operate and implement, which avoids the huge project of cabin damage and diesel engine return to the factory for repair, reduces the difficulty and complexity of repair construction, eliminates repair risks, greatly reduces repair costs, controls the impact range of the incident itself, and reduces the repair cost from tens of millions to hundreds of thousands;

[0055] 4. The method and device for repairing the main bearing cap in the cabin of this scheme overcomes the technical difficulties of repairing the main bearing cap in the cabin of a large-power marine diesel engine, and provides a new method for repairing the main bearing cap in the cabin of a diesel engine with similar structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the diesel engine cabin structure of the present invention;

[0057] Figure 2 This is a schematic diagram of the structure of the diesel engine in the A direction in the engine room of the present invention;

[0058] Figure 3 This is a schematic diagram of the structure of the B-direction diesel engine in the engine room of the present invention;

[0059] Figure 4 It is a schematic diagram of repairing the main bearing cap in the engine room of the present invention.

[0060] Figure 5 It is a schematic diagram of the maintenance of the main bearing cap in the engine room in the direction of A′ according to the present invention.

[0061] Figure 6 It is a schematic diagram of the maintenance of the main bearing cap B′ in the engine room of the present invention.

[0062] Figure 7 It is a schematic diagram of the triangular plate type whole machine lifting device in the present invention.

[0063] Figure 8 It is a schematic diagram of the supporting tooling in the present invention.

[0064] Fig. 9 It is a schematic diagram of the fuselage propping-up device in the present invention.

[0065] In the figure:

[0066] 1Diesel engine 1-1Fuse body 1-2Crankshaft 1-3Main bearing cap 1-3KSOutput end main bearing cap 1-3KGSFree end main bearing cap 1-4Main bearing bolt 1-5Main bearing round nut 1-6Transverse bolt 1-7Eye bolt 1-8Support bracket 1-9Rubber isolator 1-10I-beam 1-11Oil pan 1-12Oil pan bolt 1-13Fluid coupling 1-14Transmission box

[0067] 2 boxes

[0068] 3 Engine room 3-1 Bottom deck 3-2 Second deck 3-3 Third deck 4 Machine lifting device 4-1 Triangular hanging plate 4-2 D-type shackle 1 4-3 Special steel rope 4-4 D-type shackle 2

[0069] 5Support tooling5-1 bottom plate5-2 vertical plate5-3 reinforcement plate5-4 top plate

[0070] 6 plastic sheet 7 sleepers 8 wooden board

[0071] 9 Body expansion device 9-1 Left-handed stud 9-2 Expansion nut 9-3 Right-handed stud 10 Manual hoist

[0072] 11 machine lifting points 12 lifting straps

[0073] L1 is the lifting distance between the diesel engine lifting eye bolts

[0074] L2 is the distance from the diesel engine to the third deck

[0075] L3 is the diesel engine lifting height

[0076] α is the tilt angle of the oil pan during disassembly and assembly. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0078] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0079] See also Figure 1-9 , details of the embodiments of the present invention.

[0080] Embodiment 1: A device for repairing the main bearing cap in a cabin of a high-power marine diesel engine, comprising a combined tool for repairing the main bearing cap in the cabin, the combined tool comprising a triangular plate type whole machine lifting device 4, a supporting tool 5, an oil pan disassembly and cleanliness protection device, and a fuselage propping device 9;

[0081] The triangular plate type whole machine hoist 4 is provided with two sets and is used to be installed on the output end KS and the free end KGS of the diesel engine 1 respectively. The upper end of the triangular plate type whole machine hoist 4 is fastened to the whole machine lifting point 11 fixed on the third deck 3-3 of the cabin 3 through a manual hoist 10; the triangular plate type whole machine hoist 4 can realize the lifting of the whole machine in the narrow space in the cabin.

[0082] The supporting fixtures 5 are provided in four sets and are respectively fixed at the four corners of the bottom of the diesel engine 1 which is hoisted a certain distance to support the diesel engine 1;

[0083] The oil pan disassembly and cleanliness protection device is used to protect the oil pan 1-11 from disassembly and cleanliness;

[0084] The fuselage opening device 9 is installed at the adjacent fuselage 1-1 openings of the two main bearing caps 1-3 at the output end and the free end of the diesel engine and is used to open the fuselage 1-1.

[0085] In a specific embodiment: see Figure 7 As shown, the triangular plate type whole machine hoist 4 includes a triangular hanging plate 4-1, and the two lower corners of the triangular hanging plate 4-1 are connected to a special steel rope 4-3 through a D-type shackle 14-2, and the lower end of the special steel rope 4-3 is used to connect and fasten with the eye bolt 1-7 on the diesel engine 1, and the upper corner of the triangular hanging plate 4-1 is connected to the manual hoist 10 through a D-type shackle 24-4, and the manual hoist 10 is fastened to the whole machine lifting point 11 welded on the third deck 3-3.

[0086] Preferably, the distance between the two special steel ropes 4-3 at the lower part of the triangular hanging plate 4-1 is determined according to the lifting distance L1 of the lifting eye bolt 1-7 on the diesel engine.

[0087] In a specific embodiment: see Figure 8 As shown, the structure of the supporting tooling 5 includes two vertical plates 5-2 symmetrically fixed between a bottom plate 5-1 and a top plate 5-4, and a reinforcing plate 5-3 fixed between the two vertical plates 5-2; the bottom plate 5-1 is used to be fastened to the I-beam 1-10 on the diesel engine 1, and the top plate 5-4 is used to be fastened to the supporting bracket 1-8 on the diesel engine 1.

[0088] When this embodiment is used, the fastening bolts of the rubber isolator 1-9 and the supporting bracket 1-8 and the I-beam 1-10 on the diesel engine 1 are removed, the height L3 of the diesel engine 1 to be lifted should be greater than 800mm, and the four supporting fixtures 5 are fixed between the supporting bracket 1-8 and the I-beam 1-10 with machine belt bolts.

[0089] In a specific embodiment: see Figure 4 As shown, the oil pan disassembly and cleanliness protection device includes a plastic sheet 6 for laying on the oil pan 1-11, a sleeper 7 for padding under the oil pan 1-11, and a wooden board 8 for laying on the I-beam 1-10 at the output end and free end of the diesel engine 1 and used as a maintenance work platform.

[0090] When this embodiment is used, two groups of 1t manual hoists are installed on the crossbeam frame of the box body 2, and two 1t slings 12 are used to disassemble and assemble the oil pan 1-11. Two sleepers 7 are placed under the oil pan 1-11, and a plastic sheet 6 is placed on the oil pan to protect the cleanliness. Wooden boards 8 are placed on the I-beams 1-10 at the output end KS and the free end KGS of the diesel engine 1 for the operator's maintenance work platform.

[0091] In a specific embodiment: see Fig. 9 As shown, the fuselage expansion device 9 includes a left-handed stud 9-1 and a right-handed stud 9-3 for supporting the opening on the fuselage 1-1A and B sides, and an expansion nut 9-2 threadedly connecting the left-handed stud 9-1 and the right-handed stud 9-3.

[0092] When this embodiment is used, a hydraulic pump with two hydraulic tensioners is used, which are installed on the main bearing round nut 1-5 and pressed to disassemble it from the main bearing bolt 1-4; a common torque wrench is used to disassemble the transverse bolt 1-6 from the main bearing cover 1-3; the fuselage opening device 9 is installed at the adjacent fuselage 1-1 opening of the main bearing covers 1-3KS and 1-3KGS to open the fuselage 1-1.

[0093] The combined tool in this embodiment has the following characteristics:

[0094] 1) The combined tool has a reasonable structural design, low-cost materials, low manufacturing difficulty, easy use, and high safety factor. It can meet the safety operation requirements of lifting, disassembly, and protection when repairing the main bearing cover of the diesel engine in the cabin. Through combined application, it is suitable for various types of major maintenance operations of diesel engines in the cabin. It is easy to operate and has strong promotion.

[0095] 2) The triangular plate type integral hoist has a simple structure and occupies a small space (L2≤1.5m), which is convenient for lifting the whole machine in the narrow space in the cabin. The triangular hanging plate is preferably cut and formed by 45GB / T699 steel plate, and three lifting holes for drilling and installing the shackle are drilled. The hanging plate is subjected to a 15t hanging weight test. The material cost is low, the processing difficulty is low, the transportation and use are convenient, safe and reliable, and it can be adjusted according to the center distance L1 of the diesel engine eye bolt, and has strong adaptability. The D-type shackle GB / T25854 with a threaded shaft pin structure with holes and shoulders is preferred. The ultimate working load of the D-type shackle 1 is preferably 6 level 10t, and the ultimate working load of the D-type shackle 2 is preferably 6 level 20t. High-strength calm alloy steel is preferred, with high strength, high reliability, and high safety factor, and it has strong combined connectivity with steel ropes, manual hoists, and hanging plates. The special steel rope is preferably a 10t double-twisted steel wire rope, which is light in weight, high in strength, can withstand impact loads, has good flexibility, is flexible to use, and is low in cost. The manual hoist is preferably a 20t round structure, alloy steel material, the chain is an 800Mpa high-strength lifting chain, medium-frequency quenching heat treatment, small size, light weight, easy to carry, small tension, and slow lifting. The two whole machine lifting points welded on the three-layer deck are preferably Q235A carbon steel plates, which have strong weldability, less damage to the deck, and are easy to strengthen the structure.

[0096] 3) The 4-point support fixture for fixing the diesel engine is preferably made of 5 independent Q235A carbon steel plates, which are cut, processed and welded, with reserved weld grooves and full-melt arc welding. The structure has high strength and is firmly welded. The vertical plate can be adjusted according to the lifting height L3 to adapt to the diesel engine support of different heights and create an operating space that meets the maintenance of the main bearing cap. The bottom plate matches the bolt holes on the I-beam, the top plate matches the bolt holes on the support bracket, and the fasteners of the original rubber isolator are used to firmly connect the diesel engine to the bottom deck.

[0097] 4) For the oil pan disassembly and cleanliness protection device, low-cost wood, plastic and other materials are selected, and the combination design meets the requirements of protection, lifting and other operations. It is highly practical and easy to make and select. It is preferred to spread a whole piece of transparent plastic cloth on the oil pan. It is light and easy to use. It is a disposable consumable material that can adapt to the larger installation surface of the oil pan and prevent foreign matter and other dirt from contaminating the oil pan lubricating oil system; 2 sleepers are preferred, made of ordinary hardwood, placed between the oil pan and the bottom deck to prevent contamination of the oil pan and facilitate lifting of the oil pan; wooden boards are preferred, hard oak, and the materials must be able to withstand a pressure of 200 kg, without cracks and other defects, and used for replacing the main bearing cover in the cabin; 2t slings are preferred, made of synthetic fiber, which are soft and tough, and easy to lift and protect the oil pan.

[0098] 5) The fuselage expansion and bolt tightening device is used for the disassembly and assembly of the main bearing cap. The main bearing cap can be quickly disassembled and assembled when used in combination. The bolt tightening pressure and the amount of expansion of the fuselage are stable and controllable, which is suitable for the disassembly and assembly of various types of interference fit main bearing caps. The fuselage expansion device is exquisitely designed, and the left and right threads are matched. The left side is designed as a left-handed thread connection, and the right side is designed as a right-handed thread connection. The studs on both sides are cut with notches to increase the contact area with the fuselage opening. The outer circle of the expansion nut is designed to tighten the square head, and the threaded hole is designed with a back-off groove. The fuselage can be expanded by rotating the nut with an open-end wrench. The expansion amount can be calculated based on the pitch. The expansion of the fuselage should be controlled within 0.5mm.

[0099] Embodiment 2: A method for repairing a main bearing cap in a cabin of a high-power marine diesel engine, based on a combined tool for repairing a main bearing cap in a cabin, the method comprising the following steps:

[0100] Step 1): Peripheral system removal: See Figure 1 , 4 As shown, disconnect the oil, water, gas and electricity connections on the periphery of the diesel engine 1, and remove all systems and devices in the engine room 3 that affect the maintenance of the main bearing caps 1-3 of the diesel engine;

[0101] Step 2): Removal of the box: See Figure 1 , 4 As shown, the soundproof box 2 outside the diesel engine is removed, and the pipeline between the soundproof box 2 and the diesel engine is disconnected; this meets the diesel engine lifting and main bearing cover maintenance requirements;

[0102] Step 3): Preparation before diesel engine lifting: Refer to Figure 4 , 5 As shown, confirm the whole machine lifting point 11 on the third deck 3-3, install the triangular plate whole machine lifting device 4 and the manual hoist 10 on the diesel engine eye bolt 1-7, and adjust the height of the manual hoist to effectively connect it with the whole machine lifting point 11;

[0103] Step 4): Remove the vibration isolator and lift the diesel engine: Figure 1 , 4 5, remove the rubber vibration isolator 1-9 between the support bracket 1-8 and the I-beam 1-10 at the bottom of the diesel engine 1, and use the manual hoist 10 to slowly and steadily lift the diesel engine 1 to the set height L3; install the supporting tool 5 between the support bracket 1-8 and the I-beam 1-10 of the diesel engine, support it at the support of the A4, A7, B4, and B7 cylinder engines, and place the sling 12 and the sleeper 7 at the bottom of the oil pan 1-11;

[0104] Step 5): Remove the oil pan: See Figure 4 , 5 As shown in FIG. 6 , loosen the oil pan bolts 1-12, remove the connecting oil pipe from the oil pan 1-11 to the transmission box 1-14, use the sling 12 to slowly move the oil pan 1-11 out from between the hydraulic coupler 1-13 and the transmission box 1-14 at an angle of α, and place it on the sleeper 7; cover the oil pan 1-11 with a whole piece of clean plastic sheet 6, and lay plywood on the plastic sheet 6 for protection; lay wooden boards 8 under the main bearing cover that needs to be replaced as a working platform;

[0105] Step 6): Remove the main bearing cap: Figure 1 , 4 As shown, remove the front and rear output end main bearing caps 1-3KS and the free end main bearing caps 1-3KGS, loosen the transverse tension bolts 1-6, and use the fuselage opening device 9 to open the fuselage 1-1; use the hydraulic tensioner to remove the main bearing cap nuts 1-5, and increase the pressure of the hydraulic tensioner by a manual pump from the set pressure to check whether the nuts can be loosened at every 5MPa increase. Pay attention to the control oil pressure and the length changes of the main bearing studs 1-4, remove the main bearing caps, and mark and protect them;

[0106] Step 7): Copy a new main bearing cap: Use the method of precise 3D scanning and mapping to fit the 3D digital model of the faulty main bearing cap, form a manufacturing drawing, and process a new main bearing cap with controllable accuracy and up to standard quality;

[0107] Step 8): Install the new main bearing cap: Figure 1 , 4 As shown, the fuselage 1-1 is propped open by the fuselage propping device 9, and the corresponding new main bearing cap is reinstalled to the corresponding position of the diesel engine 1 according to the identification mark, and the transverse tension bolt 1-6 and the main bearing cap nut 1-5 are tightened;

[0108] Step 9): Reinstall the oil pan: See Figure 1 , 2As shown in 4, 5, and 6, remove the wooden board 8 and the plastic sheet 6 on the oil pan 1-11, use the pre-installed lifting strap 12 under the oil pan 1-11, lift the oil pan 1-11 steadily, tilt the oil pan to avoid the hydraulic coupler 1-13, install the oil pan into the fuselage 1-1, and tighten the oil pan bolts 1-12;

[0109] Step 10): Reinstall the vibration isolator and seat the diesel engine: Figure 1 , 3 As shown in 4 and 5, remove the sleepers 7 and slings 12 under the oil pan 1-11, remove the supporting fixture 5, reinstall the rubber vibration isolator 1-9, and use the manual hoist 10 to slowly lower the diesel engine so that the supporting bracket 1-8, the rubber vibration isolator 1-9, and the I-beam 1-10 are connected and fastened;

[0110] Step 11): Box body recovery: see Figure 1 As shown, the soundproof box body 2 around the diesel engine is restored, and the pipeline between the box body and the diesel engine is connected;

[0111] Step 12): Peripheral system recovery: See Figure 1 As shown, the oil, water, gas and electricity connections around the diesel engine are restored, and all systems and devices in the engine room 3 that affect the maintenance of the main bearing caps 1-3 of the diesel engine are reinstalled.

[0112] Preferably, the lifting height L3 of the diesel engine 1 is ≥800 mm, and the lifting height L3 of the diesel engine 1 is less than the distance L2 from the diesel engine to the third deck.

[0113] Preferably, the height of the supporting tooling 5 is determined according to the lifting height L3 of the diesel engine 1 .

[0114] The combined tool for in-cabin maintenance of the main bearing cap provided in this embodiment can realize the triangular plate lifting device for lifting the whole machine in the narrow space in the cabin, the 4-point support tooling for fixing the diesel engine, the oil pan disassembly and cleanliness protection device, and the body propping up and bolt tightening device when disassembling and assembling the main bearing cap, which can solve the key technical problems such as the narrow space for in-cabin maintenance of the main bearing cap, unstable shaking of the ship in water, low cleanliness, and great technical difficulty in assembling the main bearing cap; based on the above devices, a new process method for in-cabin maintenance of the main bearing cap is formed, which can effectively solve the technical difficulties in in-cabin maintenance of the main bearing cap of this type of diesel engine.

[0115] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0116] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A device for repairing the main bearing cap in a high-power marine diesel engine room, characterized in that: It comprises a combined tool for repairing the main bearing cap in the cabin, the combined tool comprising a triangular plate type whole machine lifting device (4), a supporting tool (5), an oil pan disassembly and assembly and cleanliness protection device, and a fuselage propping device (9); The triangular plate type complete machine sling (4) is provided with two sets and is respectively used to be installed on the output end and the free end of the diesel engine (1); the upper end of the triangular plate type complete machine sling (4) is fastened to the complete machine sling point (11) fixed on the third deck (3-3) of the engine room (3) through a manual hoist (10); The supporting tooling (5) is provided with four sets and is respectively fixed to the bottom of the diesel engine (1) that is hoisted a certain distance to support the diesel engine (1); The oil pan disassembly and cleanliness protection device is used to disassemble and clean the oil pan (1-11); The fuselage propping device (9) is installed at the adjacent fuselage (1-1) openings of the two main bearing caps (1-3) at the output end and the free end of the diesel engine and is used to prop open the fuselage (1-1).

2. The device for repairing the main bearing cap in a high-power marine diesel engine room according to claim 1 is characterized in that: The triangular plate type complete machine lifting device (4) comprises a triangular hanging plate (4-1), the two lower corners of the triangular hanging plate (4-1) are connected to a special steel rope (4-3) through a D-type shackle 1 (4-2), the lower end of the special steel rope (4-3) is used to be connected and fastened with a lifting eye bolt (1-7) on the diesel engine (1), the upper corner of the triangular hanging plate (4-1) is connected to a manual hoist (10) through a D-type shackle 2 (4-4), and the manual hoist (10) is fastened to a complete machine lifting point (11) welded on a three-layer deck (3-3).

3. The device for repairing the main bearing cap in a high-power marine diesel engine room according to claim 2 is characterized by: The distance between the two special steel ropes (4-3) at the lower part of the triangular hanging plate (4-1) is determined according to the lifting distance L1 of the lifting eye bolts (1-7) on the diesel engine.

4. The device for repairing the main bearing cap in a high-power marine diesel engine room according to claim 1 is characterized by: The structure of the supporting tooling (5) comprises two vertical plates (5-2) symmetrically fixed between a bottom plate (5-1) and a top plate (5-4), and a reinforcing plate (5-3) fixed between the two vertical plates (5-2); the bottom plate (5-1) is used for fastening connection with an I-beam (1-10) on a diesel engine (1), and the top plate (5-4) is used for fastening connection with a supporting bracket (1-8) on the diesel engine (1).

5. The device for repairing the main bearing cap in a high-power marine diesel engine room according to claim 1 is characterized by: The oil pan disassembly and cleanliness protection device comprises a plastic sheet (6) for laying on the oil pan (1-11), a sleeper (7) for padding under the oil pan (1-11), and a wooden board (8) for laying on the I-beam (1-10) at the output end and free end of the diesel engine (1) to serve as a maintenance operation platform.

6. The device for repairing the main bearing cap in a high-power marine diesel engine room according to claim 1 is characterized by: The fuselage expansion device (9) comprises a left-handed stud (9-1) and a right-handed stud (9-3) for supporting the opening on the A and B sides of the fuselage (1-1), and an expansion nut (9-2) threadedly connecting the left-handed stud (9-1) and the right-handed stud (9-3).

7. A method for repairing a main bearing cap in a high-power marine diesel engine room, characterized in that: Based on the combined tool for in-cabin maintenance of main bearing caps, the method comprises the following steps: Step 1): Dismantle the peripheral system: disconnect the oil, water, gas and electricity connections outside the diesel engine (1), and remove all systems and devices in the engine room (3) that affect the maintenance of the main bearing cap (1-3) of the diesel engine; Step 2): Dismantling the box body: dismantling the soundproof box body (2) outside the diesel engine, and disconnecting the pipeline between the soundproof box body (2) and the diesel engine; Step 3): Preparation work before diesel engine lifting: confirm the whole engine lifting point (11) on the third deck (3-3), install the triangular plate whole engine lifting device (4) and the manual hoist (10) on the diesel engine eyebolt (1-7), and adjust the height of the manual hoist to effectively connect it with the whole engine lifting point (11); Step 4): Remove the vibration isolator and lift the diesel engine: remove the rubber vibration isolator (1-9) between the support bracket (1-8) and the I-beam (1-10) at the bottom of the diesel engine (1), and use a manual hoist (10) to slowly and steadily lift the diesel engine (1) to a set height L3; install the support tooling (5) between the support bracket (1-8) and the I-beam (1-10) of the diesel engine, and place the sling (12) and the sleeper (7) at the bottom of the oil pan (1-11); Step 5): Remove the oil pan: Loosen the oil pan bolts (1-12), remove the connecting oil pipe from the oil pan (1-11) to the transmission case (1-14), use the sling (12) to slowly move the oil pan (1-11) out from between the hydraulic coupler (1-13) and the transmission case (1-14) at an angle of α, and place it on the sleeper (7); Cover the oil pan (1-11) with a whole piece of clean plastic sheet (6), and lay plywood on the plastic sheet (6) for protection; Lay a wooden board (8) under the main bearing cover that needs to be replaced as a working platform; Step 6): Remove the main bearing cap: remove the output end main bearing cap (1-3KS) and the free end main bearing cap (1-3KGS) of the front and rear gears, loosen the transverse tension bolts (1-6), and use the machine body opening device (9) to open the machine body (1-1); use the hydraulic tensioner to remove the main bearing cap nut (1-5), remove the main bearing cap, mark it, and protect it; Step 7): Copy a new main bearing cap: Use the method of precise 3D scanning and mapping to fit the 3D digital model of the faulty main bearing cap, form a manufacturing drawing, and process a new main bearing cap with controllable accuracy and up to standard quality; Step 8): Install the new main bearing cap: Use the body opening device (9) to open the body (1-1), reinstall the corresponding new main bearing cap to the corresponding position of the diesel engine (1) according to the identification mark, and tighten the transverse tension bolt (1-6) and the main bearing cap nut (1-5); Step 9): Reinstall the oil pan: remove the wooden board (8) and plastic sheet (6) on the oil pan (1-11), use the pre-installed lifting strap (12) under the oil pan (1-11) to steadily lift the oil pan (1-11), install the oil pan into the fuselage (1-1), and tighten the oil pan bolts (1-12); Step 10): Reinstall the vibration isolator and place the diesel engine in place: remove the sleepers (7) and slings (12) under the oil pan (1-11), remove the supporting tooling (5), reinstall the rubber vibration isolator (1-9), and use a manual hoist (10) to slowly lower the diesel engine so that the supporting bracket (1-8), the rubber vibration isolator (1-9), and the I-beam (1-10) are butt-jointed and then fastened; Step 11): Restoring the box body: Restoring the soundproof box body (2) around the diesel engine, and connecting the pipeline between the box body and the diesel engine; Step 12): Peripheral system recovery: Restore the oil, water, gas and electricity connections around the diesel engine, and reinstall all systems and devices in the engine room (3) that affect the maintenance of the main bearing cap (1-3) of the diesel engine.

8. A method for repairing a main bearing cap in a high-power marine diesel engine room according to claim 7, characterized in that: The lifting height L3 of the diesel engine (1) is ≥800 mm, and the lifting height L3 of the diesel engine (1) is less than the distance L2 from the diesel engine to the third deck.

9. A method for repairing a main bearing cap in a high-power marine diesel engine room according to claim 8, characterized in that: The height of the supporting tooling (5) is determined according to the lifting height L3 of the diesel engine (1).

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