Analog thrust device for thrust pad refurbishment

Abstract

The utility model discloses a kind of simulation thrust devices for thrust pad repair, it includes: rotating component, it contains fixedly connected one-way thrust ball bearing and fixed disc, one-way thrust ball bearing is connected with steam turbine shaft, the center of fixed disc is equipped with recess;Fixed support, it is located in the side of fixed disc, and center is provided with mounting hole;Trapezoidal nut, it is fixed in mounting hole;Trapezoidal screw, it is set on fixed support through trapezoidal nut;The top of trapezoidal screw is embedded in recess, rotating component is pressed on steam turbine shaft, rotates trapezoidal screw simulation axial thrust, and axial thrust is transmitted to rotating component by trapezoidal screw and trapezoidal nut.The utility model has realized the continuous and stable simulation axial thrust when steam turbine working thrust pad contact surface overall repair, ensure that thrust pad contact surface overall repair quality is close to or in line with the real state of steam turbine operation.

Description

Technical Field

[0001] This utility model relates to the field of thrust bearing repair, and in particular to a simulated thrust device for thrust bearing repair. Background Technology

[0002] Thrust bearings are critical components in large rotating equipment, primarily used to withstand the axial thrust of the rotor and ensure its stable axial position. Thrust bearing maintenance is essential for the normal operation of a steam turbine. Thruster bearing over-polishing is a key maintenance task aimed at ensuring the flatness and contact performance of the thrust bearing surface to maintain the stable operation of the generator set. Specifically, the quality requirements for thrust bearing contact surface over-polishing are: the contact area between the thrust bearing and the thrust disc should be greater than 75%, and the contact surface should be uniformly distributed. This can be achieved by grinding a tungsten gold coating onto the surface of the thrust bearing blocks.

[0003] During turbine overhaul, the traditional overhaul process consists of two steps: first, the contact surfaces of individual thrust bearing pads are individually ground to meet quality standards; then, the more crucial overall grinding is performed. In overall grinding, the rotor is rotated 2 to 3 times, and a load simulating the axial thrust during operation is applied to the thrust disc. Then, targeted scraping is done based on the contact marks on the pad surfaces. This process needs to be repeated multiple times until all thrust bearing pads are in uniform contact.

[0004] However, a significant drawback of existing technologies is the lack of a dedicated device capable of accurately and stably simulating rotor axial thrust. In practice, simple methods (such as levers or jacks) are typically used to apply force, but these methods suffer from inaccurate force direction, uncontrollable load magnitude, and poor stability, leading to distorted contact marks, difficulty in ensuring repair accuracy, and a high degree of dependence on the operator's experience for maintenance quality.

[0005] The statements herein provide only background information relating to this invention and do not necessarily constitute prior art. Utility Model Content

[0006] The purpose of this invention is to provide a simulated thrust device for thrust bearing repair, so as to realize continuous and stable simulation of axial thrust during the overall repair of the contact surface of the working thrust bearing of a steam turbine, and ensure that the overall repair quality of the contact surface of the thrust bearing is close to or conforms to the actual operating state of the steam turbine.

[0007] To achieve the above objectives, this utility model provides a simulated thrust device for thrust bearing maintenance, comprising: a rotating assembly including a fixedly connected one-way thrust ball bearing and a fixed disk, the one-way thrust ball bearing being connected to a turbine shaft, the fixed disk having a groove at its center; a fixed bracket located on one side of the fixed disk, with a mounting hole at its center; a trapezoidal nut fixed within the mounting hole; and a trapezoidal screw passing through the trapezoidal nut and mounted on the fixed bracket; the top of the trapezoidal screw is embedded in the groove, pressing the rotating assembly against the turbine shaft, rotating the trapezoidal screw to simulate axial thrust, and transmitting the axial thrust to the rotating assembly through the trapezoidal screw and the trapezoidal nut.

[0008] Optionally, the axis of the rotating assembly, the axis of the trapezoidal nut, and the axis of the trapezoidal screw are at the same horizontal level.

[0009] Optionally, a front bearing seat is also provided on the outer side of the turbine shaft for fixing and supporting the fixed bracket.

[0010] Optionally, the inner wall of the trapezoidal nut has a first trapezoidal thread, and at least a portion of the surface of the trapezoidal screw has a second trapezoidal thread that matches the first trapezoidal thread. The first trapezoidal thread and the second trapezoidal thread are engaged to transmit axial thrust.

[0011] Optionally, the one-way thrust ball bearing consists of a housing ring, a shaft ring, and a ball assembly. The housing ring is fixedly connected to the fixed disk, the shaft ring is connected to the turbine shaft, and the ball assembly is disposed between the housing ring and the shaft ring.

[0012] Optionally, the top of the trapezoidal screw is tapered and matches the shape of the groove so that the sidewall of the top fits tightly against the inner wall of the groove.

[0013] Optionally, the ratio of the depth of the groove to the length of the top head is 1 / 3 to 2 / 3.

[0014] Optionally, a screw handwheel is provided at one end of the trapezoidal screw opposite to the top head, and the screw handwheel is arranged perpendicular to the trapezoidal screw.

[0015] Optionally, the fixing plate and the fixing bracket are made of carbon steel.

[0016] Optionally, the trapezoidal nut is made of brass, and the trapezoidal screw is made of stainless steel.

[0017] Compared with existing technologies, this invention has at least the following advantages: By setting up a rotating component, a fixed bracket, and cooperating with the trapezoidal screw and the trapezoidal nut, axial thrust is transmitted to the rotating component, thereby enabling a continuous and stable simulated axial thrust during the overall finishing of the turbine's thrust bearing contact surface, ensuring that the overall finishing quality of the thrust bearing contact surface is close to or conforms to the actual operating state of the turbine. Secondly, by setting up a fixed bracket, the trapezoidal screw, the trapezoidal nut, and the rotating component are coaxially arranged, ensuring the accuracy of the applied direction of the simulated thrust. Simultaneously, by controlling the number of engagements of the first and second trapezoidal threads, the magnitude of the simulated axial thrust can be effectively adjusted, achieving controllable load magnitude and thus improving the stability of the simulated axial thrust. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the split structure of the simulated thrust device for thrust bearing repair according to the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the simulated thrust device for thrust bearing repair of this utility model when it is in working condition. Detailed Implementation

[0020] The simulated thrust device for thrust bearing repair proposed in this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this utility model will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this utility model. Please refer to the drawings to make the objectives, features, and advantages of this utility model more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0021] To ensure a continuous and stable simulated axial thrust during the overall finishing of the thrust bearing contact surface, and to guarantee that the finishing quality of the thrust bearing contact surface closely approximates or conforms to the actual operating conditions of the turbine, such as... Figures 1-2As shown, an embodiment of this utility model provides a simulated thrust device 100 for thrust bearing maintenance, comprising: a rotating assembly 101, which includes a fixedly connected one-way thrust ball bearing 110 and a fixed disk 114, the one-way thrust ball bearing 110 being connected to a turbine shaft 200, and the fixed disk 114 having a groove 115 at its center; a fixed bracket 102 located on one side of the fixed disk 114, and having a mounting hole 121 at its center; a trapezoidal nut 103 fixedly installed in the mounting hole 121; and a trapezoidal screw 10. 4. The trapezoidal nut 103 passes through the fixed bracket 102; the top 141 of the trapezoidal screw 104 is embedded in the groove 115. By applying a screwing thrust to the trapezoidal screw 104, the rotating assembly 101 is pressed onto the turbine shaft 200. The trapezoidal screw 104 is rotated to simulate axial thrust, and the axial thrust is transmitted to the rotating assembly 101 through the trapezoidal screw 104 and the trapezoidal nut 103, thereby achieving continuous and stable simulation of axial thrust during the overall finishing of the turbine working thrust bearing contact surface. Optionally, the fixed plate 114 and the fixed bracket 102 are made of carbon steel to ensure that the strength of the fixed plate 114 and the fixed bracket 102 can meet the load-bearing requirements; the trapezoidal nut 103 is made of brass (e.g., H62 brass), and the trapezoidal screw 104 is made of stainless steel.

[0022] The turbine shaft 200 also has a front bearing housing (not shown in the figure) on its axial outer side. This front bearing housing is a standard structure for turbines, and in this invention, it is used to fix and support the fixed bracket 102. Specifically, as... Figure 2 As shown, the top and bottom of the fixed bracket 102 are respectively provided with connection holes 122. In some embodiments, the connection holes 122 of the fixed bracket 102 are fixed to the front bearing seat by bolts, so that the rotating assembly 101 is located between the front bearing seat and the turbine shaft 200.

[0023] Furthermore, to ensure the uniformity of the overall finishing of the contact surface of the working thrust pads, such as... Figure 2 As shown, the axes of the rotating assembly 101 (i.e., the axes of the one-way thrust ball bearing 110 and the fixed disk 114), the trapezoidal nut 103, and the trapezoidal screw 104 are at the same horizontal level. This ensures that all components of the simulated thrust device 100 are coaxially aligned with the turbine shaft, improving the accuracy of the simulated thrust direction and guaranteeing the authenticity of the contact imprints on the tile surface, thus improving the overall precision of the tile contact surface finishing. Simultaneously, the groove 115 on the fixed disk 114 engages with the top 141 of the trapezoidal screw 104, fixing the direction of the screw's thrust.

[0024] Among them, such as Figure 1 and Figure 2 As shown, the one-way thrust ball bearing 110 consists of a housing ring 112, a shaft ring 111, and a ball assembly 113. The housing ring 112 is fixedly connected to the fixed disk 114, and the shaft ring 111 is connected to the turbine shaft 200. The ball assembly 113 is disposed between the housing ring 112 and the shaft ring 111. In some embodiments, the ball assembly 113 is a single unit formed by pressing together steel balls and a cage to reduce rotational friction. Furthermore, the diameters of the one-way thrust ball bearing 110 and the fixed disk 114 are matched according to the diameter of the turbine shaft 200. It should be noted that, in order to ensure the normal operation of the one-way thrust ball bearing 110, the axial load borne by the one-way thrust ball bearing 110 during operation must not be less than the minimum axial load, and the one-way thrust ball bearing 110 can only bear axial loads in one direction and cannot bear radial loads. In this embodiment, the direction of the spiral thrust of the trapezoidal screw 104 must be consistent with the direction of the shaft system in order to ensure the actual quality of the overall grinding of the working thrust pad.

[0025] To improve the load-bearing capacity of the simulated thrust device, in this embodiment, the inner wall of the trapezoidal nut 103 has a first trapezoidal thread, and at least a portion of the surface of the trapezoidal screw 104 (i.e., the portion overlapping with the trapezoidal nut 103) has a second trapezoidal thread that matches the first trapezoidal thread. The first trapezoidal thread and the second trapezoidal thread mesh to transmit axial thrust. Since the second trapezoidal thread matching the first trapezoidal thread is an isosceles trapezoid, its root is wider and stress concentration effect is smaller compared to traditional square threads. This allows it to withstand greater axial loads without shear failure or fracture. Simultaneously, the symmetrical tooth profiles of the first and second trapezoidal threads cause radial forces to cancel each other out during transmission, helping to maintain good alignment between the trapezoidal screw 104 and the trapezoidal nut 103, reducing uneven wear and vibration, ensuring uniform rotation, and improving the overall precision of the bearing contact surface finishing. In this embodiment, the magnitude of the simulated axial thrust applied to the turbine shaft can be adjusted by controlling the number of engagements of the first trapezoidal thread and the second trapezoidal thread, thereby achieving controllability of the load magnitude and improving the stability of the simulated axial thrust.

[0026] like Figure 1 and Figure 2As shown, the top 141 of the trapezoidal screw 104 is conical. Since the axial thrust between the trapezoidal screw 104 and the groove 115 is transmitted through static friction, the shape of the top 141 of the trapezoidal screw 104 matches the shape of the groove 115 so that the sidewall of the top 141 fits tightly against the inner wall of the groove 115, increasing the contact area between the top 141 and the groove 115, thereby improving the static friction between them and improving the transmission efficiency of the axial thrust. As an optional embodiment, the ratio of the depth d of the groove 115 to the length L of the top 141 is 1 / 3 to 2 / 3. Under the premise of ensuring effective friction transmission of the conical surface, a gap of greater than or equal to 1 mm is maintained between the bottom of the groove 115 and the end of the top 141 of the trapezoidal screw 104, effectively avoiding harmful bending moments generated by the contact between the top 141 of the trapezoidal screw 104 and the bottom of the groove 115, which could damage the trapezoidal screw 104.

[0027] Furthermore, such as Figure 1 and Figure 2 As shown, a screw handwheel 105 is provided at one end of the trapezoidal screw 104 opposite to the top head 141. The screw handwheel 105 and the trapezoidal screw 104 are arranged perpendicularly to each other. By rotating the screw handwheel 105, the trapezoidal screw 104 is driven to rotate, generating a screwing thrust. This screwing thrust is a simulated axial thrust, which is transmitted to the rotating assembly 101 through the trapezoidal screw 104 and the trapezoidal nut 103, thereby providing a continuous and stable simulated axial thrust for the overall finishing of the working thrust bearing contact surface. Optionally, the screw handwheel 105 is made of 45# steel. In other embodiments, one end of the trapezoidal screw 104 opposite to the top head 141 is connected to a drive device (such as a motor) to reduce human error.

[0028] In one specific embodiment, the construction method and process for repairing and polishing the working thrust bearing specifically includes the following steps:

[0029] S1. Scraping of a single thrust bearing, including:

[0030] S11. If replacing with new tiles, the thickness of the new tiles must be determined based on the original tile thickness, thrust clearance (calculated according to the lower limit of the standard), and flow clearance, with a margin of 0.05mm to 0.10mm. When adjusting the thickness, the flatness of the tile thickness (less than 0.02mm) should be checked regularly. A dial indicator can be placed on a platform, and the tile can be moved horizontally to check. This method can also simultaneously check the thickness deviation between tiles.

[0031] S12. Apply a layer of red lead powder to the alloy surface of the bearing block and grind it on a flat plate. Use a special scraper to scrape off the larger and bright spots first, then scrape off the smaller spots, repeating this process several times until the contact points are evenly distributed and the contact point area accounts for more than 75% of the total area.

[0032] S2. After the platform passes the grinding test, the working tile is then ground as a whole, which includes:

[0033] S21. A thin layer of red lead powder is applied to the tungsten gold surface of the working tile.

[0034] S22. Remove the thrust bearing blocks on the non-working side;

[0035] S23. Reinstall the working side thrust bearing and #1 bearing, and bearing sleeper, and tighten the mating surfaces with bolts;

[0036] S3. Install the simulated thrust device 100 for thrust bearing repair provided in the above embodiment, which includes:

[0037] S31. Fix the trapezoidal nut 103 in the center hole 121 of the fixing bracket 102, and then fix the fixing bracket 102 on the front bearing seat.

[0038] S32. Screw the trapezoidal screw 104 into the trapezoidal nut 103. The top 141 of the trapezoidal screw 104 contacts the groove 115 of the fixed plate 114, pressing the rotating assembly 101 onto the shaft end of the turbine shaft 200.

[0039] S4. Rotate the rotor 2-3 times while rotating the screw handwheel 105. The screw thrust is transmitted to the turbine shaft 200 through the second trapezoidal thread on the trapezoidal screw 104 to provide an appropriate axial thrust (i.e., simulate the axial thrust during turbine operation).

[0040] S5. Repair the working tiles according to the traces of red lead powder on the working tiles; repeat steps S2 and S4 until the thrust plate is in uniform contact with all the working tiles.

[0041] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] In the description of this utility model, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, 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, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" 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 utility model according to the specific circumstances.

[0044] 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.

[0045] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above content. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A simulated thrust device for repairing thrust bearings, characterized in that, include: A rotating assembly includes a fixedly connected one-way thrust ball bearing and a fixed disk, wherein the one-way thrust ball bearing is connected to a turbine shaft, and the fixed disk has a groove at its center; A fixed bracket is located on one side of the fixed plate and has a mounting hole in the center; A trapezoidal nut, which is fixed inside the mounting hole; A trapezoidal screw, which passes through the trapezoidal nut and is mounted on the fixed bracket; The top of the trapezoidal screw is embedded in the groove, pressing the rotating assembly onto the turbine shaft. Rotating the trapezoidal screw simulates axial thrust, and the axial thrust is transmitted to the rotating assembly through the trapezoidal screw and the trapezoidal nut.

2. The simulated thrust device as described in claim 1, characterized in that, The axes of the rotating assembly, the trapezoidal nut, and the trapezoidal screw are at the same horizontal level.

3. The simulated thrust device as described in claim 1, characterized in that, A front bearing seat is also provided on the outer side of the turbine shaft for fixing and supporting the fixed bracket.

4. The simulated thrust device as described in claim 1, characterized in that, The inner wall of the trapezoidal nut has a first trapezoidal thread, and at least a portion of the surface of the trapezoidal screw has a second trapezoidal thread that matches the first trapezoidal thread. The first trapezoidal thread and the second trapezoidal thread are engaged to transmit axial thrust.

5. The simulated thrust device as described in claim 1, characterized in that, The one-way thrust ball bearing consists of a housing ring, a shaft ring, and a steel ball assembly. The housing ring is fixedly connected to the fixed disk, the shaft ring is connected to the turbine shaft, and the steel ball assembly is disposed between the housing ring and the shaft ring.

6. The simulated thrust device as described in claim 1, characterized in that, The top of the trapezoidal screw is tapered and matches the shape of the groove so that the sidewall of the top fits tightly against the inner wall of the groove.

7. The simulated thrust device as described in claim 6, characterized in that, The ratio of the depth of the groove to the length of the top head is 1 / 3 to 2 / 3.

8. The simulated thrust device as described in claim 1, characterized in that, One end of the trapezoidal screw opposite to the top head is provided with a screw handwheel, and the screw handwheel is arranged perpendicular to the trapezoidal screw.

9. The simulated thrust device as described in claim 1, characterized in that, The fixing plate and the fixing bracket are made of carbon steel.

10. The simulated thrust device as described in claim 1, characterized in that, The trapezoidal nut is made of brass, and the trapezoidal screw is made of stainless steel.

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