Auxiliary tool for replacing variable-pitch oil cylinder

Abstract

A variable-pitch oil cylinder replacement auxiliary tool comprises a pin shaft mounting assembly and a pin shaft dismounting assembly, and the pin shaft mounting assembly and the pin shaft dismounting assembly are used in cooperation to replace a pin shaft of a variable-pitch oil cylinder. The pin shaft installation assembly comprises a stop block fixing bolt rod (8), a jack fixing stop block (7), a jack (2), a pin shaft fixing stop block (6) and a nut (9). The pin shaft dismounting assembly comprises a pin shaft fixing bolt rod (1), a jack (2) and a pin shaft tool sleeve (3). The device also has the advantages of simple structure, convenience in operation, low cost and the like. Standard parts and general parts adopted by the device are easy to purchase and replace, and the maintenance cost is reduced. Meanwhile, the design of the tool fully considers the limitation of the field operation environment, and the flexibility and applicability of the tool in a narrow space are ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to wind driven generator technical field especially a kind of auxiliary tool for replacing variable pitch oil cylinder. BACKGROUND

[0002] As an important component of wind driven generator, the operation state of variable pitch system directly affects the safety and economy of wind turbine operation. Each blade of Siemens 4.0MW model is equipped with two hydraulic cylinders, and the two cylinders are arranged in parallel and opposite directions. When the fan is in the state of collecting paddle, the cylinder is in the extended state. Compared with other components of the wind turbine, the downtime caused by the damage of the blade cylinder is relatively long, and the main reason is that the variable pitch cylinder is located in the hub, and the operation space is small when replacing the variable pitch cylinder. In addition, the weight of a single cylinder is 113.4kg, and it is difficult to disassemble and assemble the fixed cylinder pin shaft, which takes a long time in the processing process.

[0003] As an important actuator of hydraulic variable pitch wind turbine, with the increase of operation time, the cylinder body is stretched and contracted frequently, which eventually leads to the reduction of hydraulic system precision and even failure. When replacing the variable pitch cylinder, it must be completed by removing and installing the pin shaft. After investigation, other offshore wind power projects of the same type also have the phenomenon of replacing the cylinder, and because of the low annual frequency, it is not a centralized batch problem, so the research and analysis of variable pitch cylinder replacement tool has not been carried out. In order to prevent the problem of long maintenance time caused by cylinder damage in advance, and also to provide relevant reference for hydraulic variable pitch model, the members of the special technical research group of Dongtai offshore wind farm studied a kind of auxiliary tool for replacing variable pitch cylinder, which effectively solved the problems of small operation space and difficult disassembly and assembly of fixed pin shaft, reduced power loss and improved operation and maintenance efficiency.

[0004] After investigation, the advantages and disadvantages of the commonly used pin shaft removal method are as follows:

[0005] (1) Hydraulic pin puller method

[0006] Principle: The huge pulling force provided by the hydraulic system can pull the pin shaft out of the hole.

[0007] Advantages: It can provide stable pulling force and accurately control the disassembly process of pin shaft; reduce the damage to pin shaft and surrounding structure.

[0008] Disadvantages: Poor applicability in limited space; high operation skill requirement, need skilled operators; high equipment cost, need special hydraulic pin puller.

[0009] (2) Mechanical removal method

[0010] Principle: Use special disassembly tools such as puller, wrench, screw, etc. to pull the pin shaft out of the hole by mechanical force.

[0011] Advantages: can provide stable mechanical force, reduce damage to the pin shaft and surrounding structure; more secure and reliable than the knocking method.

[0012] Disadvantages: difficult to operate for large pin shafts and narrow spaces, may require specially designed tools; high equipment cost, requires special disassembly tools. Invention content

[0013] To solve the problems existing in the prior art, the team members comprehensively analyze the advantages and disadvantages of the above methods, and unanimously decide to make a variable pitch cylinder replacement auxiliary tool by combining hydraulic and mechanical operations, aiming to overcome the limitations faced by single methods, while meeting the needs of on-site disassembly. Through mechanical fixation, combined with a special hydraulic device, efficient and safe disassembly can be achieved without damaging the pin shaft and the cylinder. This method not only improves work efficiency, reduces safety risks, but also reduces equipment maintenance costs, providing a strong guarantee for the stable operation of wind turbines.

[0014] The technical solution adopted by the utility model to solve its technical problems is:

[0015] A variable pitch cylinder replacement auxiliary tool, comprising a pin shaft installation assembly and a pin shaft removal assembly, the pin shaft installation assembly and the pin shaft removal assembly are used in combination to replace the pin shaft of the variable pitch cylinder.

[0016] The pin shaft installation assembly comprises block fixing bolt rods 8, jack fixing blocks 7, jacks 2, pin shaft fixing blocks 6 and nuts 9, wherein: two block fixing bolt rods 8 are installed in the pin shaft support 5 through threaded connection, the middle part of the two block fixing bolt rods 8 is sleeved with the pin shaft fixing block 6, and the pin shaft 4 is placed between the pin shaft fixing block 6 and the pin shaft support 5; the top part of the two block fixing bolt rods 8 is sleeved with the jack fixing block 7, and the jack 2 is placed between the block fixing bolt rod 8 and the pin shaft fixing block 6; the top part of the pin shaft fixing block 6 and the jack fixing block 7 is equipped with the nut 9.

[0017] The pin shaft removal assembly comprises a pin shaft fixing bolt rod 1, a jack 2 and a pin shaft tool sleeve 3; the pin shaft 4 is installed in the pin shaft support 5, the pin shaft fixing bolt rod 1 is installed at the center of the pin shaft 4 through threaded connection, the pin shaft tool sleeve 3 is sleeved at the bottom of the pin shaft fixing bolt rod 1, the jack 2 is installed at the top of the pin shaft tool sleeve 3, the jack 2 is sleeved on the pin shaft fixing bolt rod 1, and the nut 9 is installed at the top of the pin shaft fixing bolt rod 1.

[0018] The utility model also has the following additional technical features:

[0019] As a further specific optimization of the technical solution of this utility model: in the pin mounting assembly, the bottom of the pin 4 is aligned with the pin support 5, and the top of the pin 4 is located at the lower part of the pin fixing block 6.

[0020] As a further specific optimization of the technical solution of this utility model: in the pin installation assembly, the bottom of the jack 2 is aligned with the pin fixing block 6, and the top of the jack 2 is located below the jack fixing block 7.

[0021] As a further specific optimization of the technical solution of this utility model: in the pin installation assembly, the nut 9 is used to lock and limit the pin fixing block 6 and the jack fixing block 7 to the two block fixing bolt rods 8.

[0022] As a further specific optimization of the technical solution of this utility model: in the pin shaft removal assembly, the nut 9 is used to lock the jack 2 to the pin shaft fixing bolt rod 1.

[0023] Compared with the prior art, the advantages of this utility model are:

[0024] By combining hydraulic and mechanical operations, this invention provides an efficient and safe auxiliary tooling for replacing pitch cylinders. Specifically, this tooling utilizes a pin mounting assembly and a pin removal assembly to achieve rapid replacement of the pitch cylinder pins, significantly shortening maintenance time and improving operational efficiency.

[0025] In the pin mounting assembly, the ingenious design of jack 2 allows pin 4 to be stably lifted, and the precise positioning and fixation of pin is achieved through the combined use of pin fixing block 6 and jack fixing block 7. Meanwhile, the locking action of nut 9 ensures the stability and safety of the entire installation process.

[0026] In the pin removal assembly, jack 2 also plays a crucial role. By fitting it onto the pin fixing bolt rod 1 and locking it with nut 9, the pin can be quickly removed. This design not only simplifies the removal process but also reduces the risk of damage to the pin and surrounding structures.

[0027] Furthermore, this utility model has advantages such as simple structure, convenient operation, and low cost. The standard and general-purpose parts used are easy to procure and replace, reducing maintenance costs. At the same time, the design of this tooling fully considers the limitations of the on-site working environment, ensuring its flexibility and applicability in confined spaces. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the pin mounting assembly structure of this utility model;

[0029] Figure 2The pin shaft removal assembly structural schematic view of the utility model.

[0030] Mark explanation: pin shaft fixed bolt rod 1, jack 2, pin shaft tooling sleeve 3, pin shaft 4, pin shaft support 5, pin shaft fixed stopper 6, jack fixed stopper 7, stopper fixed bolt rod 8, nut 9. DETAILED DESCRIPTION

[0031] The exemplary embodiments disclosed by the utility model will be described in more detail below with reference to the drawings.

[0032] A kind of auxiliary tool for replacing variable pitch oil cylinder, including pin shaft installation assembly and pin shaft removal assembly, the pin shaft installation assembly and the pin shaft removal assembly are used to replace the pin shaft of variable pitch oil cylinder.

[0033] The pin shaft installation assembly includes stopper fixed bolt rod 8, jack fixed stopper 7, jack 2, pin shaft fixed stopper 6 and nut 9, wherein: two stopper fixed bolt rods 8 are installed in pin shaft support 5 by threaded connection, the middle part of two stopper fixed bolt rods 8 is sleeved with pin shaft fixed stopper 6, pin shaft 4 is placed between pin shaft fixed stopper 6 and pin shaft support 5, the bottom of pin shaft 4 is aligned with pin shaft support 5, and the top of pin shaft 4 is located in the lower part of pin shaft fixed stopper 6;The top of two stopper fixed bolt rods 8 is sleeved with jack fixed stopper 7, jack 2 is placed between stopper fixed bolt rod 8 and pin shaft fixed stopper 6, the bottom of jack 2 is against pin shaft fixed stopper 6, and the top of jack 2 is located in the lower part of jack fixed stopper 7;Nut 9 is installed on the top of two stopper fixed bolt rods 8 of pin shaft fixed stopper 6 and jack fixed stopper 7, and nut 9 is used to lock pin shaft fixed stopper 6 and jack fixed stopper 7 on two stopper fixed bolt rods 8.

[0034] The pin shaft removal assembly includes pin shaft fixed bolt rod 1, jack 2 and pin shaft tooling sleeve 3;Pin shaft 4 is installed in pin shaft support 5, pin shaft fixed bolt rod 1 is installed in the center of pin shaft 4 by threaded connection, pin shaft tooling sleeve 3 is sleeved with the bottom of pin shaft fixed bolt rod 1, jack 2 is installed on the top of pin shaft tooling sleeve 3, jack 2 is sleeved on pin shaft fixed bolt rod 1, nut 9 is installed on the top of pin shaft fixed bolt rod 1, and nut 9 is used to lock jack 2 on pin shaft fixed bolt rod 1.

[0035] The design and composition of a kind of auxiliary tool for replacing variable pitch oil cylinder:

[0036] The tooling design is divided into two sub-items, one for the removal of the variable pitch cylinder, and one for the installation of the variable pitch cylinder. According to the actual situation on site, since the top of the pin shaft and the pin shaft locking plate are threaded parts, the common part of the two sub-items is designed to be a screw support; since the space of the pin shaft disassembly part is limited and a large torque is required, the common hydraulic device of the two sub-items is designed to use a small jack 2. The overall design focuses on practicality and safety to ensure efficient and stable operation performance in complex environments.

[0037] (1) Composition of the removal tool

[0038] The front and rear ends of the variable pitch cylinder are fixed by pin shafts, and M30 bolt holes are reserved at the top of the pin shafts, which can be pulled out by screwing in external screws. Considering the force direction of the external screw, to ensure that the direction of the jack 2 is consistent with the direction of the screw, the jack 2 piston needs to be hollow. In order to provide a fulcrum to meet the mechanical strength of the jack 2 piston during work, a hollow pin shaft tool is designed. In summary, the main structure of the variable pitch cylinder removal tool is a jack 2 (hollow piston), an external screw, and a pin shaft tool.

[0039] (2) Composition of the installation tool

[0040] Using the method of hydraulic pressure to press in the pin shaft can accurately control the pressure rate and force range, keep the load center of gravity action line consistent with the jack 2 axis, and avoid single-point force leading to pin shaft misalignment, jamming, and other phenomena. The top pin shaft support of the cylinder is fixed by tightening two M20 bolts, two screws can be used to pass through the fixed bolt hole, and a stop block is designed at the tail of the screw to provide a force point for the jack 2 piston base. In summary, the main structure of the variable pitch cylinder installation tool is a jack 2 (hollow piston), an external screw, and a stop block.

[0041] Selection of components of a variable pitch cylinder replacement auxiliary tool:

[0042] (1) Selection of jack 2

[0043] The pin shaft pulling out and installing have differences. When the pin shaft is installed, first align the holes of the two structures, then press the pin shaft in, which does not require too much pressure. When pulling out the pin shaft, the required force will depend on the friction and any locking force that may exist (such as due to interference fit). Assuming that the pin shaft is installed by interference fit, the total force Ftotal required to remove it includes: static friction force Ffs, radial force Foverfit generated by interference fit.

[0044] Given that the volume of the pin is 0.001979 m³, the density of steel is approximately 7850 kg / m³, the mass of the pin is m = ρV = 7850 × 0.001979 ≈ 15.56 kg, and the normal force is N = mg = 15.56 × 9.81 ≈ 152.6 N.

[0045] Literature review reveals that the friction factor μ between steel and iron in an unlubricated state is 0.3. Therefore, we can conclude that:

[0046] Ffs=μsN(1)

[0047] In the formula: μs = 0.3; N = 152.6 N. Substituting the values ​​into the formula, we get: Ffs ≈ 45.78 N.

[0048] Assuming the interference fit is 0.1 mm, the radial force generated by the interference fit can be approximated as:

[0049] Foverfit = △d / d × E × A (2)

[0050] In the formula: Δd = 0.1 mm = 0.0001 m; d = 0.09 m; E is the elastic modulus of steel, approximately 210 GPa; A is the bottom area of ​​the pin, A = πr² = π(0.045)² ≈ 0.00636 m². Substituting the values ​​into the formula, we get: Foverfit ≈ 14840 N

[0051] Ftotal = Ffs + Foverfit(3)

[0052] In the formula: Ffs = 45.78 N; Foverfit = 14840 N. Substituting the values ​​into the formula, we get Ftotal ≈ 14.89 kN.

[0053] Ftotal = P2A2 × 103(4)

[0054] In the formula: Ftotal = 14.89 kN; P2 = 70 MPa. Substituting the values ​​into the formula, we get: A2 = 0.000213 m2.

[0055] A2=(π / 4)(D2-d2)(5)

[0056] In the formula: A2 is the working area of ​​the corresponding hydraulic cylinder rod chamber, taken as 0.000213 m2; d is the corresponding piston rod diameter, taken as 0.07 m. Substituting the values ​​into the formula, we can obtain that the inner diameter of the hydraulic cylinder 2, D≈0.0719 m.

[0057] The field measurement pin shaft diameter is Φ90mm, and the length is 245mm. Correspondingly, the jack 2 stroke value is not higher than 245mm. Through the above calculation, the technical parameters of the jack 2 can be obtained: the piston rod diameter is 70mm, the oil cylinder inner diameter is 80mm, the jack 2 working pressure is not less than 70MPa, and the pulling force value is 14.89KN or more, which can meet the requirements of pin shaft disassembly.

[0058] (2) Design of pin shaft tooling sleeve 3

[0059] According to the diameter Φ96mm of the stepped surface on the upper surface of the fixed end of the pin shaft, in order to avoid collision between the pin shaft and the pin shaft tooling sleeve 3 during disassembly, the inner diameter of the pin shaft tooling sleeve 3 is designed to be 100mm. In order to ensure that the piston bottom of the jack 2 has sufficient mechanical strength and can provide sufficient pressure bearing area with the pin shaft tooling sleeve 3, the thickness of the tooling sleeve is set to 20mm. The material selection of the tooling sleeve also considers wear resistance and tensile strength to ensure the reliability of long-term use. In addition, the convenient disassembly design of the tooling sleeve allows it to be quickly removed after completing the work, without affecting the subsequent maintenance work. This optimization of design details significantly improves the efficiency and safety of the entire removal process.

[0060] (3) Design of jack 2 fixed stop block

[0061] In order to ensure the stability and safety of the jack 2 during the installation of the pin shaft, a special fixed stop block is designed. The middle hole is reserved with a diameter Φ33mm hole, which is used as a spare tool for disassembling the pin shaft. When used as an assembly tool, two 170mm long strip holes are symmetrically arranged on both sides, with a nearest distance of 100mm, which is greater than the diameter Φ96mm of the stepped surface on the upper surface of the fixed end of the pin shaft. A M20 tooling screw can be vertically inserted into each long strip hole and fixed with a nut 9 on the upper side of the tooling stop block, which can prevent the piston of the jack 2 from moving during the work process and ensure the smooth progress of the disassembly process.

[0062] (4) Selection of positioning screw

[0063] In order to accurately calculate whether the screw can withstand the specified force, the yield strength of the material needs to be calculated. The formula is as follows:

[0064] A=π(d / 2)2(6)

[0065] In the formula: according to the size of the blind hole at the top end of the pin shaft, d=30mm, the value is substituted into the formula to obtain A≈706.86mm2.

[0066] σ=F / A(7)

[0067] In the formula: F=16520N, A=706.86mm2, the values are substituted into the formula to obtain σ≈23.38mPa.

[0068] And this value is much smaller than the yield strength of most engineering steel, so to save the production cost of the pin shaft fixing bolt rod 1, the material can be selected as ordinary carbon steel (yield strength about 200-350MPa) to meet the requirements. Therefore, the selected pin shaft fixing bolt rod specification is 30mm in diameter and 500mm in length (screw rod and pin shaft thread fit degree), and the material is ordinary carbon steel.

[0069] The force applied when installing the pin shaft is much smaller than the force when removing it, so the material of the stop block fixing bolt rod is the same as that of the pin shaft fixing bolt rod 1, and the specification is 20mm in diameter (the blind hole of the pin shaft support 5 is 20mm), and the length is 500mm.

[0070] The principle of a variable pitch oil cylinder replacement auxiliary tool:

[0071] (1) Remove the pin shaft: In addition to using the jack 2 and the pin shaft tool sleeve 3, the pin shaft fixing bolt rod 1 and the nut 9 (or the method of passing through the middle hole of the tool stop block and cooperating with the nut 9) are also needed. First, fix one end of the pin shaft tool sleeve 3 to the pin shaft support 5, then pass the other end of the pin shaft fixing bolt rod 1 through the jack 2 and the pin shaft tool sleeve 3 and connect it with the pin shaft, and the other end of the pin shaft fixing bolt rod 1 is in contact with the top of the jack 2 through the nut 9. Move the pin shaft fixing bolt rod 1 by pushing the nut 9 with the top of the jack 2, then move the pin shaft away from the pin shaft support 5, adjust the position of the nut 9 during the process according to the distance between the pin shaft and the upper surface of the pin shaft tool sleeve 3, and finally pull the pin shaft out of the shaft hole of the pin shaft support 5.

[0072] (2) Install the pin shaft: First, install two positioning metal rings at the root of the oil cylinder, and ensure that the metal rings are not offset or tilted during installation. Then evenly apply lubricating grease to the outer wall of the pin shaft, place the pin shaft into the hole of the pin shaft support 5, and then install the tool threaded rod. Use the tool jack to fix the stop block 7 to fix the jack 2, and use the nut 9 to fix it. The pin shaft fixing stop block 6 of the fixed pin also needs to be installed to prevent the piston of the jack 2 from damaging the fixed pin shaft. Finally, the top of the jack 2 is in contact with the pin shaft top block, and the pin shaft top block is moved along the pin shaft axis direction until the pin shaft is inserted into the shaft hole of the pin shaft support 5 and tightly connected.

[0073] The beneficial effects of a variable pitch oil cylinder replacement auxiliary tool:

[0074] The cost of the tool is only 1,000 yuan, which is significantly lower than the equipment cost required by the traditional method. At the same time, the application of the tool simplifies the installation and removal steps, and the disassembly time is shortened from 4h to 1.7h, with an efficiency improvement of more than 57%, reducing downtime and personnel costs, and providing great convenience for the operation and maintenance of wind turbine generators.

[0075] The above detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application.

Claims

1. A variable pitch cylinder replacement auxiliary tool, characterized in that: It comprises a pin shaft installation assembly and a pin shaft removal assembly, which are used in cooperation to replace the pin shaft of the variable pitch cylinder; wherein: The pin shaft installation assembly comprises a stop block fixing bolt rod (8), a jack fixing stop block (7), a jack (2), a pin shaft fixing stop block (6) and a nut (9), wherein: two stop block fixing bolt rods (8) are installed in the pin shaft support (5) through threaded connection, the middle part of the two stop block fixing bolt rods (8) is sleeved with the pin shaft fixing stop block (6), the pin shaft (4) is placed between the pin shaft fixing stop block (6) and the pin shaft support (5); the top of the two stop block fixing bolt rods (8) is sleeved with the jack fixing stop block (7), the jack (2) is placed between the stop block fixing bolt rod (8) and the pin shaft fixing stop block (6); the nut (9) is installed on the top of the two stop block fixing bolt rods (8) of the pin shaft fixing stop block (6) and the jack fixing stop block (7) in cooperation; The pin shaft removal assembly comprises a pin shaft fixing bolt rod (1), a jack (2) and a pin shaft tool sleeve (3); the pin shaft (4) is installed inside the pin shaft support (5), the pin shaft fixing bolt rod (1) is installed at the center of the pin shaft (4) through threaded connection, the pin shaft tool sleeve (3) is sleeved at the bottom of the pin shaft fixing bolt rod (1), the jack (2) is installed at the top of the pin shaft tool sleeve (3), the jack (2) is sleeved on the pin shaft fixing bolt rod (1), and the nut (9) is installed at the top of the pin shaft fixing bolt rod (1).

2. The auxiliary tool for replacing a pitch cylinder according to claim 1, characterized in that: In the pin shaft installation assembly, the bottom of the pin shaft (4) is aligned with the pin shaft support (5), and the top of the pin shaft (4) is located below the pin shaft fixing stop block (6).

3. The auxiliary tool for replacing a pitch cylinder according to claim 1, characterized in that: In the pin shaft installation assembly, the bottom of the jack (2) is aligned with the pin shaft fixing stop block (6), and the top of the jack (2) is located below the jack fixing stop block (7).

4. The auxiliary tool for replacing a pitch cylinder according to claim 1, characterized in that: In the pin shaft installation assembly, the nut (9) is used to lock the pin shaft fixing stop block (6) and the jack fixing stop block (7) on the two stop block fixing bolt rods (8).

5. The auxiliary tool for replacing a pitch cylinder according to claim 1, characterized in that: In the pin shaft removal assembly, the nut (9) is used to lock the jack (2) on the pin shaft fixing bolt rod (1).

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