A method for replacing a water-lubricated bearing

Abstract

The present invention provides a water-lubricated bearing replacement method, which can replace the water-lubricated bearing without dismantling the shaft, and the replacement process includes the disassembly and reinstallation of the water-lubricated bearing. By using the replacement method provided by the present invention to replace the water-lubricated bearing, the position of the shaft system can be accurately controlled to ensure that the inner surface of the water-lubricated bearing is not damaged during the installation of the bearing; the epoxy resin coated on the shaft system can be effectively protected to avoid repairing and re-coating the epoxy resin after the construction process, saving costs and time. The present invention reduces the conventional disassembly and assembly of rudder blades, rudder rods, shafts, hydraulic couplings and other related projects generated for replacing water-lubricated bearings, greatly reduces related related projects, reduces the docking period, speeds up the maintenance progress, shortens the entire repair cycle, and allows the ship to be put into operation faster, saving a lot of costs for the shipowner.

Description

Technical Field

[0001] The invention belongs to the technical field of ships, and in particular relates to a method for replacing a water-lubricated bearing. Background Art

[0002] The shaft system is the power transmission component of the ship and the core component of the ship's operation. The shaft system is supported by bearings to ensure the normal operation of the shaft system. With the advancement of technology and the enhancement of people's environmental awareness, water-lubricated bearings have been used more and more widely.

[0003] During the operation of the shaft system, the bearings will gradually wear out over time. The bearing clearance is measured during each docking inspection to understand the operation of the shaft system. When the measured bearing clearance exceeds the corresponding repair clearance standard, the bearing needs to be replaced to ensure that the entire shaft system can operate normally when sailing at sea.

[0004] Water-lubricated bearings are divided into integral and half types. The replacement of integral water-lubricated bearings requires the removal of the propeller shaft and stern shaft before the water-lubricated bearings can be replaced. Figure 2 As shown in the figure, the half-type water-lubricated bearing consists of an upper and lower part, with a sealing strip installed in the middle. The outer part of the bearing is a copper sleeve, which is installed with the inner hole of the bearing seat through an interference fit. The inner part of the bearing is a flying dragon bearing strip, and the entire bearing is fixed to the bearing seat with bolts through the end face flange.

[0005] Half-type water-lubricated bearings can be replaced by integral water-lubricated bearings or without removing the shaft system or rudder system. Replacing bearings without removing the shaft can greatly reduce the amount of work, reduce the docking period, shorten the repair time, and save repair costs.

[0006] Although there are many advantages to replacing water-lubricated bearings without disassembling the shaft, there are the following difficulties during the replacement process:

[0007] 1. The clearance between the shaft and the bearing is very small. Without disassembling the shaft, the position of the shaft needs to be precisely controlled to ensure smooth disassembly and assembly without damaging the inner surface of the water-lubricated bearing.

[0008] 2. In the process of fixing the shaft, it is necessary to design the fixing position and fixing method to protect the epoxy resin on the shaft.

[0009] 3. To prevent seawater from corroding the bearing seat hole, sealing strips are installed on the contact surfaces of the two half bearings. A reasonable installation sequence needs to be designed to ensure that the sealing strips are in the correct installation position. Summary of the invention

[0010] In order to solve the above technical problems, the present invention provides a water-lubricated bearing replacement method, which accurately fixes and adjusts the shaft system and has a reasonable installation sequence. The water-lubricated bearing can be replaced smoothly without dismantling the shaft.

[0011] The objective of the present invention is achieved through the following technical solution, a method for replacing a water-lubricated bearing, comprising the following steps:

[0012] Step 1: Water-lubricated bearing removal

[0013] Step 1.1: Clean the marine growth and other attachments on the water-lubricated bearing mounting flange, hub and nearby shafts;

[0014] Step 1.2: Weld the main hanging bracket and auxiliary hanging bracket above the propeller shaft and stern shaft;

[0015] Step 1.3: Remove the stern shaft sealing device components that affect the stern shaft lifting height;

[0016] Step 1.4: Lift the propeller shaft and stern shaft;

[0017] Step 1.5: Place the tooling frame and jack behind the stern tube bearing to raise the stern tube.

[0018] Step 1.6: Place a tooling frame and a jack under the intermediate shaft in the cabin to raise the intermediate shaft;

[0019] Step 1.7: Remove the upper half of the bearing from the stern hub;

[0020] Step 1.8: Remove the lower half of the bearing from the stern hub;

[0021] Step 1.9: Repeat steps 1.1-1.8 to disassemble the front stern shaft frame water-lubricated bearing and the rear stern shaft frame water-lubricated bearing;

[0022] Step 2: Water-lubricated bearing reinstallation

[0023] Step 2.1: Clean and treat the contact parts between the shaft, hub and bearing;

[0024] Step 2.2: Use the hand chain hoist, tooling frame and jack to adjust the position of the propeller shaft and stern shaft, and try to make the shaft in the center of the bearing seat hole;

[0025] Step 2.3: Install the lower half bearing;

[0026] Step 2.4: Install the upper half bearing;

[0027] Step 2.5: Observe the clearance between the inner hole of the bearing and the shaft, and between the outer circle of the bearing and the bearing seat hole. Use a hand chain hoist and a jack to adjust the position of the propeller shaft and the stern shaft so that the clearances in all directions are as consistent as possible to facilitate the continued pressing of the bearing.

[0028] Step 2.6: Gradually press the bearing into the bearing seat hole;

[0029] Step 2.7: When the bearing is almost in place, install the O-ring on the end flange;

[0030] Step 2.8: Install the water-lubricated bearing end cover, tighten the mounting bolts of the end cover according to the torque requirements, and take loosening measures.

[0031] Preferably, in step 1.2, the main hanging weight is located directly above the shaft, and an auxiliary hanging weight is installed on each side of the main hanging weight for adjusting the left and right position of the shaft.

[0032] Preferably, in step 1.4, the specific method for lifting the propeller shaft and the stern shaft is: hang the hand winch on the lifting ear, lift the propeller shaft and the stern shaft with a sling, try to increase the contact area between the sling and the shaft to prevent damage to the fiberglass reinforced plastic on the shaft, and the position of the sling should not hinder the removal of the bearing.

[0033] Preferably, in step 1.5, the specific method for raising the stern shaft is: place a tooling frame and a jack behind the stern shaft tube bearing to raise the stern shaft, first place a thick steel plate above the jack, and then place a Sailong bearing pad with a length of more than 400mm and basically the same as the shaft arc, and a rubber gasket needs to be placed above the Sailong bearing pad to prevent damage to the fiberglass sheathing of the shaft system.

[0034] Preferably, in step 1.6, the specific method of lifting the intermediate shaft is: placing a tooling frame and a jack under the intermediate shaft in the cabin to lift the intermediate shaft, and placing wooden blocks at the lifting position of the shaft to prevent damage to the shaft during the lifting process. Before the lifting begins, remove the upper cover of the intermediate bearing in front of the lifting position.

[0035] Preferably, in step 1.8, the method for removing the lower half of the bearing from the stern hub is: lift the shaft at the stern tube bearing position inside and outside the cabin using a jack to separate the bottom of the shaft from the water-lubricated bearing, remove the connecting bolts between the lower half bearing bushing and the end face of the bearing seat, clean the ejector screw holes of the lower half bushing, install the ejector screw to remove the lower half of the bearing from the stern hub, and use a supporting tool to support and fix the shaft.

[0036] Preferably, in step 2.3, the specific method for installing the lower half bearing is: apply grease to the O-ring groove on the half surface of the lower half bearing, install the O-ring into the sealing groove, and after the O-ring is installed, install the front end of the lower half bearing into the bearing seat hole.

[0037] Preferably, in step 2.4, the specific method for installing the upper half bearing is: lift the upper half bearing, place it on the lower half bearing, install press screws on both the upper and lower half bearings, and slowly press the upper half bearing into the bearing seat hole until the end face mounting flanges of the upper and lower half bearings are flush.

[0038] Preferably, in step 2.6, the specific method for gradually pressing the bearing into the bearing seat hole is: tighten the press nuts on both sides of the bearing at the same time, continue to press the upper half of the bearing into the bearing seat hole, and after pressing it in for a certain distance, start pressing the lower half of the bearing until the end faces of the mounting flanges of the upper and lower half bearings are close, repeat the above operation, and gradually press the bearing into the bearing seat hole.

[0039] Preferably, in step 2.6, during the process of pressing the bearing, observe the amount of pressing on the left and right sides of the bearing, and there should be no deviation. The upper and lower half bearings are pressed in alternately to avoid excessive deformation of the middle O-ring. If the pressing process is difficult, check the clearance at each position of the bearing and adjust the position of the propeller shaft and the intermediate shaft to avoid damaging the inner surface of the water-lubricated bearing.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] The present invention provides a water-lubricated bearing replacement method, which replaces the water-lubricated bearing without dismantling the shaft. The replacement process includes disassembly and reinstallation of the water-lubricated bearing. The water-lubricated bearing can be replaced by using the replacement method provided by the present invention, and the position of the shaft system can be accurately controlled to ensure that the inner surface of the water-lubricated bearing is not damaged during the installation of the bearing; the epoxy resin coated on the shaft system can be effectively protected to avoid repairing and re-coating the epoxy resin after the construction process, saving costs and time. The present invention reduces the conventional disassembly and assembly of rudder blades, rudder stocks, shafts, hydraulic couplings and other related projects generated for replacing water-lubricated bearings, greatly reduces related related projects, reduces the docking period, speeds up the maintenance progress, shortens the entire repair cycle, and allows the ship to be put into operation faster, saving a lot of costs for the shipowner. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A flow chart of the steps of a water-lubricated bearing replacement method in the present invention;

[0043] Figure 2 It is a diagram of a water-lubricated bearing in the prior art;

[0044] Figure 3 is a shaft arrangement diagram in an embodiment of the present invention;

[0045] Figure 4 is a shaft support arrangement diagram in an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the rear stern shaft frame bearing seat hole in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0048] like Figure 1 As shown, the technical solution of the present invention provides a method for replacing a water-lubricated bearing, which specifically includes the following steps:

[0049] Step 1: Water-lubricated bearing removal

[0050] Step 1.1: Clean the marine growth and other attachments on the water-lubricated bearing mounting flange, hub and nearby shafts;

[0051] Step 1.2: Weld the main hanging bracket and auxiliary hanging bracket above the propeller shaft and stern shaft;

[0052] Step 1.3: Remove the stern shaft sealing device components that affect the stern shaft lifting height;

[0053] Step 1.4: Lift the propeller shaft and stern shaft;

[0054] Step 1.5: Place the tooling frame and jack behind the stern tube bearing to raise the stern tube.

[0055] Step 1.6: Place a tooling frame and a jack under the intermediate shaft in the cabin to raise the intermediate shaft;

[0056] Step 1.7: Remove the upper half of the bearing from the stern hub;

[0057] Step 1.8: Remove the lower half of the bearing from the stern hub;

[0058] Step 1.9: Repeat steps 1.1-1.8 to disassemble the front stern shaft frame water-lubricated bearing and the rear stern shaft frame water-lubricated bearing;

[0059] Step 2: Water-lubricated bearing reinstallation

[0060] Step 2.1: Clean and treat the contact parts between the shaft, hub and bearing;

[0061] Step 2.2: Use the hand chain hoist, tooling frame and jack to adjust the position of the propeller shaft and stern shaft, and try to make the shaft in the center of the bearing seat hole;

[0062] Step 2.3: Install the lower half bearing;

[0063] Step 2.4: Install the upper half bearing;

[0064] Step 2.5: Observe the clearance between the inner hole of the bearing and the shaft, and between the outer circle of the bearing and the bearing seat hole. Use a hand chain hoist and a jack to adjust the position of the propeller shaft and the stern shaft so that the clearances in all directions are as consistent as possible to facilitate the continued pressing of the bearing.

[0065] Step 2.6: Gradually press the bearing into the bearing seat hole;

[0066] Step 2.7: When the bearing is almost in place, install the O-ring on the end flange;

[0067] Step 2.8: Install the water-lubricated bearing end cover, tighten the mounting bolts of the end cover according to the torque requirements, and take loosening measures.

[0068] In one embodiment of the present invention, during the maintenance of a ship, its water-lubricated bearings are replaced. The ship is a dual-shaft propulsion ship, and the shaft system is equipped with water-lubricated bearings at the rear end of the stern tube, the front stern shaft frame, and the rear stern shaft frame. The propeller shaft is 13.5m long, the stern shaft is 13.3m long, and the propeller shaft and the stern shaft are connected by a hydraulic coupling. The shaft system is arranged as follows: Figure 3 shown.

[0069] During the inspection of the ship in the dock, it was found that the clearance of the water-lubricated bearing of the rear stern shaft frame exceeded the limit of repair and replacement. Although the other two water-lubricated bearings were also worn, the clearance was still within the normal working range. After comprehensive consideration, it was finally decided to replace all three water-lubricated bearings.

[0070] The specific steps are as follows:

[0071] Step 1: Water-lubricated bearing removal

[0072] Step 1.1: Clean the water-lubricated bearing mounting flange, hub and nearby shafts of marine growth and other attachments.

[0073] Step 1.2: Weld 4 main hanging brackets and auxiliary hanging brackets above the propeller shaft and the stern shaft. The main hanging bracket is located directly above the shaft, and an auxiliary hanging bracket is installed on each side of the main hanging bracket to adjust the left and right position of the shaft. The specific positions of the hanging brackets are as follows: Figure 4 The shaft support arrangement is shown in the diagram.

[0074] Step 1.3: Remove the stern shaft seal components that affect the stern shaft lifting height.

[0075] Step 1.4: Hang the hand chain hoist on the lifting lug, and use the sling to lift the propeller shaft and stern shaft, and try to increase the contact area between the sling and the shaft to prevent damage to the fiberglass reinforced plastic on the shaft. At the same time, the position of the sling should not hinder the removal of the bearing.

[0076] Step 1.5: Place a tooling frame and a jack behind the stern tube bearing to raise the stern shaft. Place a thick steel plate on the jack first, and then place a Sailong bearing pad with a length of more than 400mm that is basically consistent with the shaft arc. A rubber gasket needs to be placed on the Sailong bearing pad to prevent damage to the fiberglass coated on the shaft system. The lifting position is Figure 4 Middle tooling support point 1.

[0077] Step 1.6: Place a tooling frame and a jack under the intermediate shaft in the cabin to lift the intermediate shaft. Place wooden blocks at the lifting position of the shaft to prevent damage to the shaft during the lifting process. Before lifting, remove the upper cover of the intermediate bearing in front of the lifting position. The lifting position is Figure 4 Middle tooling support point 2.

[0078] Step 1.7: Remove the safety wire and bolts of the gland at the rear end of the stern tube water-lubricated bearing, remove the gland, remove the bolts connecting the upper half of the bearing bushing and the end face of the bearing seat, clean the ejector screw holes of the upper half of the bushing, install the ejector bolts and remove the upper half of the bearing from the stern hub.

[0079] Step 1.8: Use a jack to raise the shaft at the stern tube bearing position inside and outside the cabin to separate the bottom of the shaft from the water-lubricated bearing, remove the connecting bolts between the lower half of the bearing bushing and the end face of the bearing seat, clean the ejector screw holes of the lower half of the bushing, install the ejector screw to remove the lower half of the bearing from the stern hub, and use the support tooling to support and fix the shaft.

[0080] Step 1.9: Use the same method to remove the front stern shaft frame water-lubricated bearing and the rear stern shaft frame water-lubricated bearing.

[0081] After the water-lubricated bearing is removed, the external copper sleeve of the bearing is repaired, the internal Feilong bearing strips are replaced, and then the inner diameter of the bearing is processed according to the outer diameter of the shaft copper sleeve at the bearing installation position and the drawing requirements. After processing, the water-lubricated bearing is reinstalled.

[0082] Step 2: Water-lubricated bearing reinstallation

[0083] Step 2.1: Remove burrs and rust from the contact areas between the shaft and the hub and the bearing, clean them with a detergent, and apply vaseline or grease inside the bearing seat hole and on the surface of the bearing copper sleeve; put the internal seal in place and use Loctite 495 to bond the seal; apply grease before installing the fasteners.

[0084] Step 2.2: Use a hand chain hoist, a work stand and a jack to adjust the position of the propeller shaft and the stern shaft, and try to keep the shaft in the center of the bearing seat hole to facilitate the installation of the water-lubricated bearing. When installing, please note that the upper half of the bearing is marked with "TOP" on the outer diameter of the bearing mounting flange.

[0085] Step 2.3: Apply grease to the O-ring groove on the half surface of the lower half bearing, install the O-ring into the sealing groove, and after the O-ring is installed, install the front end of the lower half bearing into the bearing seat hole to a depth of 400mm.

[0086] Step 2.4: Lift the upper half of the bearing and place it on the lower half of the bearing. Install the press screws on both the upper and lower half of the bearing and slowly press the upper half of the bearing into the bearing seat hole until the end faces of the upper and lower half of the bearing are flush with the mounting flanges. Figure 5 As shown, the interior of the rear stern shaft frame bearing seat hole is designed in a stepped form with a larger outside and a smaller inside. The front end of the bearing is easy to install. During the installation process, protect the O-ring in the half surface.

[0087] Step 2.5: Observe the clearance between the inner hole of the bearing and the shaft, and between the outer circle of the bearing and the bearing seat hole. Use a hand winch and a jack to adjust the position of the propeller shaft and the stern shaft to make the clearance in each direction as consistent as possible to facilitate the continued pressing of the bearing.

[0088] Step 2.6: Tighten the press-in nuts on both sides of the bearing at the same time, and continue to press the upper half of the bearing into the bearing seat hole. After pressing in to 100mm, start pressing in the lower half of the bearing until the end faces of the mounting flanges of the upper and lower half bearings are close. Repeat the above operation and gradually press the bearing into the bearing seat hole. During the pressing process, observe the pressing amount on the left and right sides of the bearing, and there should be no deviation. The upper and lower half bearings should be pressed in alternately to avoid excessive deformation of the middle O-ring. If pressing in is difficult, check the clearance at each position of the bearing and adjust the position of the propeller shaft and the intermediate shaft to avoid damaging the inner surface of the water-lubricated bearing.

[0089] Step 2.7: When the bearing is about to be installed in place, install the O-ring on the end flange, press the bearing in with the end fixing bolts until the bearing is installed in place and the outer end faces of the upper and lower half bearing flanges are flush, then tighten all the bolts on the bearing mounting flange and take loosening measures.

[0090] Step 2.8: Install the water-lubricated bearing end cover, tighten the mounting bolts of the end cover according to the torque requirements, and take loosening measures.

[0091] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for replacing a water-lubricated bearing, characterized in that: The method comprises the following steps: Step 1: Water-lubricated bearing removal Step 1.1: Clean the marine growth and other attachments on the water-lubricated bearing mounting flange, hub and nearby shafts; Step 1.2: Weld the main hanging bracket and auxiliary hanging bracket above the propeller shaft and stern shaft; Step 1.3: Remove the stern shaft sealing device components that affect the stern shaft lifting height; Step 1.4: Lift the propeller shaft and stern shaft; Step 1.5: Place the tooling frame and jack behind the stern tube bearing to raise the stern tube. Step 1.6: Place a tooling frame and a jack under the intermediate shaft in the cabin to raise the intermediate shaft; Step 1.7: Remove the upper half of the bearing from the stern hub; Step 1.8: Remove the lower half of the bearing from the stern hub; Step 1.9: Repeat steps 1.1-1.8 to disassemble the front stern shaft frame water-lubricated bearing and the rear stern shaft frame water-lubricated bearing; Step 2: Water-lubricated bearing reinstallation Step 2.1: Clean and treat the contact parts between the shaft, hub and bearing; Step 2.2: Use the hand chain hoist, tooling frame and jack to adjust the position of the propeller shaft and stern shaft, and try to make the shaft in the center of the bearing seat hole; Step 2.3: Install the lower half bearing; Step 2.4: Install the upper half bearing; Step 2.5: Observe the clearance between the inner hole of the bearing and the shaft, and between the outer circle of the bearing and the bearing seat hole. Use a hand chain hoist and a jack to adjust the position of the propeller shaft and the stern shaft to make the clearance in each direction as consistent as possible so that the bearing can be pressed in further. Step 2.6: Gradually press the bearing into the bearing seat hole; Step 2.7: When the bearing is almost in place, install the O-ring on the end flange; Step 2.8: Install the water-lubricated bearing end cover, tighten the mounting bolts of the end cover according to the torque requirements, and take loosening measures.

2. A water-lubricated bearing replacement method according to claim 1, characterized in that: In step 1.2, the main hanging weight is located directly above the shaft, and an auxiliary hanging weight is installed on each side of the main hanging weight for adjusting the left and right position of the shaft.

3. A water-lubricated bearing replacement method according to claim 1, characterized in that: In step 1.4, the specific method for lifting the propeller shaft and the stern shaft is: hang the hand chain hoist on the lifting ear, lift the propeller shaft and the stern shaft with a sling, and try to increase the contact area between the sling and the shaft to prevent damage to the fiberglass reinforced plastic on the shaft. At the same time, the position of the sling should not hinder the removal of the bearing.

4. A water-lubricated bearing replacement method according to claim 1, characterized in that: In the step 1.5, the specific method for raising the stern shaft is: place a tooling frame and a jack behind the stern shaft tube bearing to raise the stern shaft, first place a thick steel plate above the jack, and then place a Sailong bearing pad with a length of more than 400mm and basically the same as the shaft arc shape, and a rubber gasket needs to be placed above the Sailong bearing pad to prevent damage to the fiberglass sheathing of the shaft system.

5. A water-lubricated bearing replacement method as claimed in claim 1, characterized in that: In step 1.6, the specific method for lifting the intermediate shaft is as follows: a tooling frame and a jack are placed under the intermediate shaft in the cabin to lift the intermediate shaft, and wooden blocks are placed at the lifting position of the shaft to prevent damage to the shaft during the lifting process; before the lifting begins, the intermediate bearing cover in front of the lifting position is removed.

6. A water-lubricated bearing replacement method as claimed in claim 1, characterized in that: In the step 1.8, the method for removing the lower half of the bearing from the stern hub is as follows: lift the shaft at the stern tube bearing position inside and outside the cabin using a jack to separate the bottom of the shaft from the water-lubricated bearing, remove the connecting bolts between the lower half bearing bushing and the end face of the bearing seat, clean the ejector screw hole of the lower half bushing, install the ejector screw to remove the lower half of the bearing from the stern hub, and use a support tool to support and fix the shaft.

7. A water-lubricated bearing replacement method according to claim 1, characterized in that: In step 2.3, the specific method for installing the lower half bearing is: apply grease to the O-ring groove on the half surface of the lower half bearing, install the O-ring into the sealing groove, and after the O-ring is installed, install the front end of the lower half bearing into the bearing seat hole.

8. A water-lubricated bearing replacement method as claimed in claim 1, characterized in that: In step 2.4, the specific method for installing the upper half bearing is: lift the upper half bearing, place it on the lower half bearing, install the press screw on both the upper and lower half bearings, and slowly press the upper half bearing into the bearing seat hole until the end face mounting flanges of the upper and lower half bearings are flush.

9. A water-lubricated bearing replacement method as claimed in claim 1, characterized in that: In step 2.6, the specific method for gradually pressing the bearing into the bearing seat hole is: tighten the press nuts on both sides of the bearing at the same time, continue to press the upper half of the bearing into the bearing seat hole, and after pressing one end, start pressing the lower half of the bearing until the end faces of the mounting flanges of the upper and lower half bearings are close, repeat the above operation, and gradually press the bearing into the bearing seat hole.

10. A water-lubricated bearing replacement method according to claim 1, characterized in that: In step 2.6, when pressing the bearing, observe the pressing amount on the left and right sides of the bearing, and there should be no deviation; Press the upper and lower half bearings in alternately to avoid excessive deformation of the middle O-ring; If there are difficulties in pressing into the bearing, check the clearances at various positions of the bearing and adjust the positions of the propeller shaft and the intermediate shaft to avoid damaging the inner surface of the water-lubricated bearing.

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