A dismounting tool and a method for dismounting a close-fitting bolt of a marine diesel engine
Patent Information
- Application Number
- CN202611081906.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-21
- Publication Date
- 2026-10-30
AI Technical Summary
但该类设有执行驱动设备的拆卸结构缺乏行程监测与限位结构，作业过程中无法精准把控液压缸活塞的运动行程，极易出现执行器过度动作的情况，进而导致液压系统压力异常、密封结构失效，引发液压油外泄问题，不仅造成油品浪费、污染作业环境，还会影响拆卸工装的运行稳定性与使用寿命，严重时会导致拆卸作业中断、损伤柴油机本体结构，无法兼顾拆卸效率、作业安全性与设备防护性，难以满足船用柴油机高精度、高可靠性的拆机作业要求
提供一种拆卸工装及船用柴油机紧配螺栓的拆卸方法，该拆卸工装以执行机构作为动力源，执行机构的缸体抵紧柴油机机体作为支撑，活塞通过转接件与紧配螺栓刚性同轴连接；驱动活塞向远离柴油机的方向轴向回退，依靠活塞产生的轴向拉力克服紧配螺栓与机体孔的过盈抱紧力，将紧配螺栓平稳拔出。通过设置指示件，指示件与活塞第二端相连并滑动穿出端盖，拉拔紧配螺栓作业时指示件跟随活塞同步向外移动，操作人员可通过指示件外露长度实时判断活塞拉出距离，精准控制拉拔进给量，防止活塞超行程拉出导致缸体内部密封件过度挤压、破损失效，有效规避液压油泄漏问题，减少机舱油污污染与液压油损耗，保证工装长时间稳定拉拔作业。指示件滑动穿设于端盖，采用机械穿出式指示件实现行程观测，无需加装电子位移传感器、电控监测模块，避免电子设备受机舱油污、潮湿、强震动环境影响，故障率低；零件拆装、清洁、更换操作简单，降低工装后期维护成本，适配船舶车间复杂拆机作业环境。
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Figure CN123000424A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of marine diesel engine assembly technology, and in particular to a disassembly tooling and a method for disassembling the fastening bolts of a marine diesel engine. Background Technology
[0002] In the field of marine diesel engine assembly technology, large marine two-stroke diesel engines require multiple tight-fitting bolts at each section during assembly to ensure assembly precision. These bolts, relying on the transition or interference fit between the bolt and bolt hole, effectively withstand the high-frequency vibrations, shear forces, and impact loads generated during engine operation, precisely constraining the relative positions of each section and preventing misalignment, loosening, or other problems at the joint surfaces. During engine disassembly, these tight-fitting bolts need to be removed. Currently, the industry relies solely on manual methods for disassembly, which presents challenges due to high difficulty and low efficiency. Furthermore, manual disassembly is prone to increasing operational risks due to improper operation.
[0003] In related technologies, some solutions use actuators (such as hydraulic cylinders) to disassemble tight bolts, significantly improving bolt disassembly efficiency and reducing manual labor intensity. However, such disassembly structures with actuators lack stroke monitoring and limit mechanisms. During operation, the movement stroke of the hydraulic cylinder piston cannot be accurately controlled, making it prone to excessive actuator movement. This can lead to abnormal hydraulic system pressure, sealing failure, and hydraulic oil leakage, resulting in oil waste, environmental pollution, and impacting the operational stability and service life of the disassembly fixtures. In severe cases, it can cause disassembly interruption and damage to the diesel engine structure. Therefore, it is impossible to balance disassembly efficiency, operational safety, and equipment protection, making it difficult to meet the high-precision and high-reliability disassembly requirements of marine diesel engines. Summary of the Invention
[0004] The purpose of this invention is to provide a disassembly tooling and a method for disassembling fastening bolts of a marine diesel engine. This method can improve the operational stability and service life of the disassembly tooling, reduce the difficulty of removing fastening bolts, improve disassembly efficiency, save manpower, and optimize the disassembly process of a marine diesel engine.
[0005] To achieve this objective, the present invention adopts the following technical solution: On one hand, a disassembly fixture is provided for disassembling fastening bolts on a marine diesel engine. The fixture includes an adapter, an actuator, and an indicator. The adapter is detachably connected to the fastening bolt to be disassembled. The actuator includes a cylinder body, a piston, and an end cap. The cylinder body is supported on the diesel engine and has a mounting hole. The end cap is detachably connected to the cylinder body to open or close one end of the mounting hole. The piston slides through the mounting hole and slides relative to the hole wall along the axial direction of the cylinder body. The adapter is detachably connected to the piston, and one end face of the adapter is flush with the first end face of the piston. The indicator is used to indicate the piston's stroke and is connected to the second end of the piston. The indicator slides through the end cap.
[0006] Preferably, the actuator further includes an elastic element disposed in the mounting hole, with its two ends abutting or connecting to the second end of the piston and the end cap, respectively.
[0007] Preferably, the piston is provided with a first connecting hole, and the adapter is provided with a second connecting hole. Both the first connecting hole and the second connecting hole extend along the axial direction of the cylinder body. The outer peripheral wall of the adapter is provided with an external thread, and the adapter is screwed into the first connecting hole through the external thread. The wall of the second connecting hole is provided with an internal thread, and one end of the fastening bolt to be disassembled can be screwed into the second connecting hole through the internal thread.
[0008] Preferably, the disassembly fixture includes multiple adapters, each adapter having a second connection hole of different sizes, and one of the multiple adapters is selectively connected to the first end of the piston.
[0009] Preferably, the piston includes multiple fixedly connected columnar connecting parts, and the mounting hole includes multiple interconnected through holes. The inner diameter of the multiple through holes corresponds one-to-one with the outer diameter of the multiple columnar connecting parts. Along the direction from the second end to the first end of the piston, the outer diameter of the multiple columnar connecting parts gradually decreases.
[0010] Preferably, the disassembly fixture also includes a handle, and a groove is provided on one end face of the adapter near the first end of the piston, and the handle is detachably connected to the inner wall of the groove.
[0011] Preferably, when the first end of the piston is flush with the lower end face of the cylinder, the end of the indicator away from the piston is flush with the end cover.
[0012] Preferably, the disassembly fixture also includes a lifting ring, which is installed on the end cap and is used to connect with the lifting equipment.
[0013] Preferably, the actuator is a hydraulic cylinder.
[0014] On the other hand, a method for disassembling fastening bolts of a marine diesel engine is provided. Nuts are screwed to both ends of the fastening bolt to be disassembled. The method for disassembling the fastening bolts of the marine diesel engine utilizes the disassembly fixtures of any of the above-mentioned technical solutions. The method for disassembling the fastening bolts of the marine diesel engine includes the following steps: Remove the nuts from both ends of the fastening bolt to be disassembled; Select an adapter that matches the size of the fastening bolt to be disassembled, and install the adapter into the piston; The disassembly tooling is hoisted to the disassembly station of the diesel engine using hoisting equipment, so that the fastening bolts to be disassembled are screwed onto the adapter. The control actuator drives the piston to move away from the diesel engine, pulling out the fastening bolts to be disassembled; During the process of pulling out the fastening bolt to be disassembled, the piston's stroke is observed through the indicator. When the movement reaches the preset value, the actuator is shut down.
[0015] The beneficial effects of this invention are as follows: This invention provides a disassembly tool and a method for disassembling fastening bolts on marine diesel engines. The disassembly tool uses an actuator as its power source, with the actuator's cylinder block pressed against the diesel engine block for support. The piston is rigidly coaxially connected to the fastening bolt via an adapter. The piston is driven to axially retract away from the diesel engine, and the axial pulling force generated by the piston overcomes the interference fit between the fastening bolt and the engine block hole, smoothly pulling out the fastening bolt. An indicator is installed, connected to the second end of the piston and sliding out through an end cap. During the bolt pulling operation, the indicator moves outward synchronously with the piston. The operator can judge the piston's pull-out distance in real time by the exposed length of the indicator, precisely controlling the pull-out feed rate. This prevents the piston from overtraveling, which could lead to excessive compression and damage to the internal cylinder seals, effectively avoiding hydraulic oil leakage, reducing engine room oil contamination and hydraulic oil consumption, and ensuring stable long-term pulling operations of the tool. The indicator slides through the end cover, and the mechanically protruding indicator realizes the travel observation. There is no need to install electronic displacement sensors or electronic control monitoring modules, which avoids the impact of engine room oil, moisture and strong vibration environment on electronic equipment, resulting in a low failure rate. The disassembly, cleaning and replacement of parts are simple, which reduces the maintenance cost of tooling in the later stage and is suitable for the complex disassembly operation environment of ship workshop. Attached Figure Description
[0016] Figure 1 This is a cross-sectional view of the disassembly fixture provided by the present invention; Figure 2 This is a side view of the disassembly fixture provided by the present invention; Figure 3 This is a first-view structural schematic diagram of the adapter of the disassembly tooling provided by the present invention; Figure 4This is a second-view structural schematic diagram of the adapter of the disassembly tooling provided by the present invention.
[0017] In the picture: 1. Adapter; 11. Second connecting hole; 12. Groove; 2. Actuator; 21. Cylinder; 22. Piston; 221. First connecting hole; 222. Columnar connecting part; 23. End cap; 24. Mounting hole; 25. Elastic element; 3. Indicator; 4. Lifting ring. Detailed Implementation
[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.
[0019] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0021] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.
[0022] Please refer to Figures 1 to 4On one hand, this embodiment provides a disassembly fixture for disassembling fastening bolts on a marine diesel engine. It includes an adapter 1, an actuator 2, and an indicator 3. The adapter 1 is detachably connected to the fastening bolt to be disassembled. The actuator 2 includes a cylinder 21, a piston 22, and an end cap 23. The cylinder 21 is supported on the diesel engine and has a mounting hole 24. The end cap 23 is detachably connected to the cylinder 21 to open or close one end of the mounting hole 24. The piston 22 slides through the mounting hole 24 and slides relative to the wall of the mounting hole 24 along the axial direction of the cylinder 21. The adapter 1 is detachably connected to the piston 22, and one end face of the adapter 1 is flush with the first end face of the piston 22. The indicator 3 indicates the stroke of the piston 22 and is connected to the second end of the piston 22. The indicator 3 slides through the end cap 23. Specifically, the actuator 2 is a hydraulic cylinder, and the indicator 3 is an indicator rod.
[0023] With this configuration, the disassembly fixture uses a hydraulic cylinder as its power source. The cylinder body 21 is pressed against the diesel engine block for support, and the piston 22 is rigidly coaxially connected to the fastening bolt via an adapter 1. The hydraulic medium drives the piston 22 to axially retract away from the diesel engine. The axial pulling force generated by the piston 22 overcomes the interference fit between the fastening bolt and the engine block hole, allowing the fastening bolt to be pulled out smoothly. Simultaneously, an indicator 3 is provided, connected to the second end of the piston 22 and sliding through the end cover 23. During the bolt pulling operation, the indicator 3 moves outward synchronously with the piston 22. The operator can judge the piston 22's pull-out distance in real time by the exposed length of the indicator 3, precisely controlling the pull-out feed amount. This prevents the piston 22 from overtraveling, which could lead to excessive compression and damage to the internal seals of the cylinder body 21, effectively avoiding hydraulic oil leakage, reducing engine compartment oil contamination and hydraulic oil consumption, and ensuring stable long-term pulling operations of the fixture. The indicator 3 is slidably inserted into the end cover 23. The mechanically inserted indicator 3 is used to realize the travel observation. There is no need to install electronic displacement sensors or electronic control monitoring modules. This avoids the impact of engine room oil, moisture and strong vibration environment on electronic equipment, resulting in a low failure rate. The disassembly, cleaning and replacement of parts are simple, reducing the maintenance cost of tooling in the later stage and adapting to the complex disassembly operation environment of ship workshop.
[0024] Alternatively, please refer to Figure 1 and Figure 2The actuator 2 also includes an elastic element 25, which is disposed in the mounting hole 24. The two ends of the elastic element 25 abut against or connect to the second end of the piston 22 and the end cap 23, respectively. This configuration, by adding elastic elements 25 at both ends, which abut or connect to the second end of the piston 22 and the end cap 23 respectively, inside the mounting hole 24 of the cylinder 21, allows the piston 22 to compress the elastic elements 25 during the pulling process of the actuator 2. This causes the elastic elements 25 to be compressed and store energy. After depressurization, the piston 22 is automatically reset by relying on the elastic potential energy, eliminating the need for manual reset operation, simplifying the work process, and improving disassembly efficiency. The compression limit of the elastic elements 25 forms a physical limit, which, together with the stroke observation structure of the indicator 3, forms a double protection, further preventing the piston 22 from over-stroke movement and causing seal damage and hydraulic oil leakage. At the same time, the elastic elements 25 can buffer the impact of the piston 22's reset, reduce the impact and wear of internal parts of the tooling, and extend the service life of the tooling. Under normal conditions, the elastic elements 25 can fix the initial position of the piston 22, which facilitates the quick replacement of the adapter 1 and the transfer and storage of the tooling, making it suitable for continuous disassembly operations in the narrow engine room of marine diesel engines.
[0025] Alternatively, please refer to Figures 1 to 3 The piston 22 is provided with a first connecting hole 221, and the adapter 1 is provided with a second connecting hole 11. Both the first connecting hole 221 and the second connecting hole 11 extend along the axial direction of the cylinder body 21. The outer peripheral wall of the adapter 1 is provided with an external thread, and the adapter 1 is screwed into the first connecting hole 221 through the external thread. The hole wall of the second connecting hole 11 is provided with an internal thread, and one end of the fastening bolt to be disassembled can be screwed into the second connecting hole 11 through the internal thread. With this configuration, the adapter 1 is screwed to the first connecting hole 221 extending axially on the piston 22 via the external thread on its outer circumference. The end of the fastening bolt to be disassembled can be screwed into the internal thread of the second connecting hole 11 of the adapter 1. The coaxial arrangement of the two-stage threads enables a reliable rigid connection between the tooling and the bolt. The thread engagement has a high load-bearing capacity and is not easy to loosen or slip under high tensile pulling conditions. With the visual stroke monitoring of the indicator 3 and the automatic reset structure of the elastic element 25, it can not only prevent the piston 22 from over-travel and cause hydraulic oil leakage, but also automatically reset the piston 22 after pressure relief. This simplifies the operation and improves the disassembly efficiency. The overall structure is suitable for the small space of the ship's engine room and the batch disassembly of heavy fastening bolts.
[0026] Furthermore, the disassembly fixture includes multiple adapters 1, each with a second connecting hole 11 of different sizes, and one of the adapters 1 is selectively connected to the first end of the piston 22. This configuration allows the disassembly fixture to be fitted with appropriate adapters 1 according to the specifications of different fastening bolts, providing strong versatility and convenient disassembly and reassembly.
[0027] Optionally, the piston 22 includes multiple fixedly connected columnar connecting parts 222, and the mounting hole 24 includes multiple interconnected through holes. The inner diameter of the multiple through holes corresponds one-to-one with the outer diameter of the multiple columnar connecting parts 222. Along the direction from the second end to the first end of the piston 22, the outer diameter of the multiple columnar connecting parts 222 gradually decreases. This configuration ensures precise one-to-one matching between the multi-stage columnar connecting parts 222 of the piston 22 and the multi-stage through holes of the mounting hole 24. Compared to a single-stage cylindrical fit structure, this forms a multi-stage stepped fit structure, enabling segmented guidance and segmented limiting. During hydraulic pulling and elastic reset reciprocating sliding, the piston 22 exhibits stronger coaxiality constraint and smoother sliding, effectively preventing unilateral wear and radial wobble of the piston 22. This eliminates the possibility of jamming or seizing under high pressure and high load conditions, significantly improving the stability of the tooling's sliding motion. Meanwhile, the mounting hole 24 is a multi-level interconnected through hole with a gradually changing hole diameter, which facilitates the smooth installation and alignment of internal components such as piston 22, elastic element 25, and seals from the large-diameter end, resulting in a higher assembly error tolerance. In the later stages, tooling maintenance, cleaning, and replacement of seals and elastic element 25 are smoother to disassemble and assemble without forced disassembly and assembly, reducing maintenance difficulty and adapting to the frequent disassembly and maintenance operation scenarios in shipyards.
[0028] Optionally, when the first end of piston 22 is flush with the lower end face of cylinder 21, the end of indicator 3 furthest from piston 22 is flush with end cap 23. With this configuration, in the initial assembly state where the tooling is not in operation and the first end of piston 22 is flush with the lower end face of cylinder 21, the outer end of indicator 3 is exactly flush with the end face of end cap 23. This flush position serves as the stroke zero-point marker. Operators can quickly check the zero point before each operation without additional ruler calibration, quickly confirming that piston 22 is in its initial position and avoiding stroke judgment errors caused by premature displacement of piston 22 before operation.
[0029] Alternatively, please refer to Figure 3 and Figure 4 The disassembly fixture also includes a handle. A groove 12 is provided on one end face of the adapter 1 near the first end of the piston 22, and the handle is detachably connected to the inner wall of the groove 12. Specifically, the groove 12 is a slot that runs radially through the adapter 1. With this configuration, when it is necessary to disassemble or replace the adapter 1, the handle can be easily inserted into the groove 12 on the end face of the adapter 1, and the threaded connection between the adapter 1 and the piston 22 can be easily completed by rotating the handle, thereby improving the efficiency of disassembly and assembly of the adapter 1. When the actuator 2 is performing a pulling operation, the handle can be removed to prevent the exposed handle from colliding with the equipment in the engine room. The handle can be stored separately, reducing the space occupied by the fixture.
[0030] Alternatively, please refer to Figure 1 and Figure 2The disassembly fixture also includes a lifting ring 4, which is installed on the end cover 23 and is used to connect with lifting equipment. This configuration allows the disassembly fixture to be lifted as a whole using lifting equipment via the lifting ring 4, facilitating transport, reducing the labor intensity of manual lifting, and preventing personnel injuries and machine damage caused by heavy object handling. The lifting point is located at the end cover 23, ensuring balanced lifting force and preventing the fixture from tilting or deflecting during transport, effectively protecting precision components such as the adapter 1 and indicator 3. Furthermore, when disassembling multiple fastening bolts on the diesel engine, the disassembly fixture needs to be moved across workstations; it can be suspended and moved using the lifting ring 4, making operation convenient and efficient.
[0031] On the other hand, this embodiment provides a method for disassembling a fastening bolt of a marine diesel engine. Nuts are screwed to both ends of the fastening bolt to be disassembled. The method for disassembling the fastening bolt of the marine diesel engine utilizes the aforementioned disassembly fixture and includes the following steps: Remove the nuts from both ends of the fastening bolt to be disassembled; Select an adapter 1 that matches the size of the fastening bolt to be disassembled, and install the adapter 1 into the piston 22; The disassembly fixtures are hoisted to the disassembly station of the diesel engine using hoisting equipment, so that the fastening bolts to be disassembled are screwed onto the adapter 1; The control actuator 2 drives the piston 22 to move away from the diesel engine, pulling out the fastening bolt to be disassembled; During the process of pulling out the fastening bolt to be disassembled, the movement stroke of piston 22 is observed through indicator 3; When the motion stroke reaches the preset value, actuator 2 is turned off.
[0032] Optionally, when it is necessary to replace the adapter 1, insert the handle into the groove 12 of the adapter 1 installed in the disassembly fixture and unscrew it; then screw the new adapter 1 into the first connecting hole 221 of the piston 22 until the end face of the adapter 1 is flush with the end face of the first end of the piston 22.
[0033] This disassembly method first removes the nuts at both ends of the fastening bolt to eliminate disassembly interference. A suitable adapter 1 is pre-installed on the piston 22. Then, the tooling is hoisted to the disassembly station using a lifting ring 4 and hoisting equipment, reducing the intensity of manual handling and the risk of working at heights. The tooling and the fastening bolt are connected by a double-layer coaxial thread, ensuring even pulling force without eccentric loading, thus avoiding damage to the engine body and bolts. During the pulling process, the operator monitors the piston 22's stroke in real time using an indicator 3. Once the stroke reaches the preset value, the actuator 2 is shut down, effectively preventing hydraulic oil leakage caused by over-travel of the piston 22. After disassembly and depressurization, the elastic element 25 drives the piston 22 to automatically reset to the zero position, eliminating the need for manual reset, simplifying the operation process and improving disassembly efficiency. The entire operation process is standardized and controllable, overcoming the shortcomings of traditional manual disassembly, such as high difficulty, low efficiency, and high safety risks, meeting the requirements for efficient, safe, and non-destructive disassembly of fastening bolts in large marine two-stroke diesel engines.
[0034] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A disassembly tool for removing fastening bolts on a marine diesel engine, characterized in that, include: Adapter (1), the adapter (1) being used for detachable connection with the fastening bolt to be disassembled; An actuator (2) is provided, comprising a cylinder (21), a piston (22), and an end cap (23). The cylinder (21) is used to support a diesel engine. The cylinder (21) is provided with a mounting hole (24). The end cap (23) is detachably connected to the cylinder (21) to open or close one end of the mounting hole (24). The piston (22) slides through the mounting hole (24) and slides relative to the hole wall of the mounting hole (24) along the axial direction of the cylinder (21). An adapter (1) is detachably connected to the piston (22), and one end face of the adapter (1) is flush with the first end face of the piston (22). Indicator (3), the indicator (3) is used to indicate the stroke of the piston (22), the indicator (3) is connected to the second end of the piston (22), and the indicator (3) slides through the end cap (23).
2. The disassembly fixture according to claim 1, characterized in that, The actuator (2) further includes an elastic element (25), which is disposed in the mounting hole (24). The two ends of the elastic element (25) abut against or connect to the second end of the piston (22) and the end cap (23), respectively.
3. The disassembly fixture according to claim 1, characterized in that, The piston (22) is provided with a first connecting hole (221), and the adapter (1) is provided with a second connecting hole (11). Both the first connecting hole (221) and the second connecting hole (11) extend along the axial direction of the cylinder (21). The outer peripheral wall of the adapter (1) is provided with an external thread. The adapter (1) is screwed into the first connecting hole (221) through the external thread. The hole wall of the second connecting hole (11) is provided with an internal thread. One end of the fastening bolt to be disassembled can be screwed into the second connecting hole (11) through the internal thread.
4. The disassembly fixture according to claim 3, characterized in that, The disassembly fixture includes multiple adapters (1), each adapter (1) having a second connection hole (11) of different sizes, and one of the multiple adapters (1) is selectively connected to the first end of the piston (22).
5. The disassembly fixture according to claim 3, characterized in that, The piston (22) includes a plurality of fixedly connected columnar connecting parts (222), and the mounting hole (24) includes a plurality of interconnected through holes. The inner diameter of the plurality of through holes corresponds one-to-one with the outer diameter of the plurality of columnar connecting parts (222). Along the direction from the second end to the first end of the piston (22), the outer diameter of the plurality of columnar connecting parts (222) gradually decreases.
6. The disassembly fixture according to claim 1, characterized in that, The disassembly fixture also includes a handle. The adapter (1) has a groove (12) on one end face near the first end of the piston (22). The handle is detachably connected to the inner wall of the groove (12).
7. The disassembly fixture according to claim 1, characterized in that, When the first end of the piston (22) is flush with the lower end face of the cylinder (21), the end of the indicator (3) away from the piston (22) is flush with the end cap (23).
8. The disassembly fixture according to claim 1, characterized in that, The disassembly fixture also includes a lifting ring (4), which is installed on the end cap (23) and is used to connect with the lifting equipment.
9. The disassembly fixture according to any one of claims 1-8, characterized in that, The actuator (2) is a hydraulic cylinder.
10. A method for disassembling a fastening bolt of a marine diesel engine, wherein nuts are screwed onto both ends of the fastening bolt to be disassembled, characterized in that... The method for disassembling the fastening bolts of the marine diesel engine uses the disassembly fixture described in any one of claims 1-9, and the method for disassembling the fastening bolts of the marine diesel engine includes the following steps: Remove the nuts from both ends of the fastening bolt to be disassembled; Select the adapter (1) that matches the size of the fastening bolt to be disassembled, and install the adapter (1) into the piston (22); The disassembly fixture is hoisted to the disassembly station of the diesel engine using hoisting equipment, so that the fastening bolts to be disassembled are screwed onto the adapter (1); The actuator (2) is controlled to drive the piston (22) to move away from the diesel engine and pull out the fastening bolt to be disassembled; During the process of pulling out the fastening bolt to be disassembled, the movement stroke of the piston (22) is observed through the indicator (3); When the motion stroke reaches the preset value, the actuator (2) is turned off.