Integral rotor support and method of manufacturing thereof

Abstract

The present application relates to rotor support manufacturing technical field, specifically relates to a kind of integrated rotor support and its manufacturing method: by the overall welding forming of rotor support, annealing heat treatment and all machining processes are all completed in manufacturing plant, fundamentally eliminate the welding deformation problem caused by the assembly welding of support arm and center body of traditional split rotor support in construction site, and the machining precision of key features such as magnetic yoke key groove, pin sleeve hole is directly guaranteed by one-time clamping of high-precision numerical control machine tool in factory, avoid the precision loss caused by welding deformation in construction site and secondary processing in construction site;At the same time, by completing the pre-assembly matching of rotor support and main shaft in manufacturing plant, the concentricity and axis consistency of rotor and main shaft are completely guaranteed by machining precision and pre-assembly data in factory, eliminate the connection deviation and security risk caused by the adjustment link such as same drill reaming in construction site, significantly improve the operation reliability and long-term stability of unit.

Description

Technical Field

[0001] This invention relates to the field of rotor support manufacturing technology, and in particular to an integrated rotor support and its manufacturing method. Background Technology

[0002] The turbine generator set is the core equipment of a hydroelectric power station. Its rotor support, as a key load-bearing component connecting the main shaft and the yoke, undertakes the important functions of transmitting huge torque, supporting the mass of the rotating parts, and ensuring the stable operation of the unit.

[0003] Traditionally, for rotor supports of large hydro-generator sets with an outer diameter exceeding 5 meters, a segmented structural design is commonly adopted due to limitations in the manufacturing plant's processing equipment capabilities, transportation clearance conditions, and on-site hoisting capabilities. A typical traditional design involves disassembling the rotor support into a central rotor body and several supporting arms. These are initially processed separately at the manufacturing plant and then transported to the construction site. The supporting arms are then assembled and welded to the central rotor body within the turbine pit, thus assembling the segmented components into a single unit. After on-site welding is completed, secondary processing or finishing of the magnetic yoke keyway and simultaneous drilling and reaming of the connecting holes between the rotor support and the main shaft are performed.

[0004] However, traditional segmented rotor supports can never fundamentally eliminate the impact of on-site welding deformation on accuracy, resulting in problems such as long installation cycles, low connection accuracy, and poor operational reliability. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated rotor support and its manufacturing method, which solves the problems of traditional segmented rotor supports that cannot fundamentally eliminate the impact of on-site welding deformation on accuracy, resulting in long installation cycles, low connection accuracy, and poor operational reliability.

[0006] To achieve the above objectives, the present invention provides a method for manufacturing an integrated rotor support, the method comprising the following steps: Integral welding: The rotor support is integrally welded in the manufacturing plant. The rotor support has a disc-shaped structure and is used in hydro-generator sets. Its outer diameter is greater than 5 meters. Post-weld annealing: The welded integral rotor support is subjected to annealing heat treatment; Overall precision machining: The annealed integral rotor support is clamped and positioned in the manufacturing plant using a high-precision CNC machine tool to complete all machining processes of the rotor support. The machining processes include at least the machining of the magnetic yoke keyway and the pin sleeve hole. Pre-assembly and matching in the factory: The rotor support and the main shaft are pre-assembled and matched in the manufacturing plant, and connected and positioned by a pin sleeve structure; Overall transportation and on-site hoisting: The finished integrated rotor bracket is transported to the construction site and hoisted directly into place.

[0007] In the overall welding forming step, the rotor support is welded using multi-layer multi-pass welding or narrow-gap submerged arc welding process. The preheating temperature before welding is 100℃ to 150℃, the interpass temperature is controlled not to exceed 200℃, and 100% ultrasonic flaw detection is performed after welding, so that the weld quality level reaches Grade 1.

[0008] In the post-weld annealing step, the heating rate of the annealing heat treatment is controlled at 50℃ / h to 80℃ / h, the holding temperature is 550℃ to 620℃, the holding time is 2h to 4h, the cooling rate is controlled at 30℃ / h to 50℃ / h, and after cooling to below 200℃, the furnace is removed and air-cooled, and the residual stress relief rate is not less than 85%.

[0009] In the overall finishing process, the pin sleeve hole is machined using a boring die process. The boring die guides the pin sleeve hole and works with a high-precision boring machine to ensure that the hole diameter accuracy reaches H7 level and the hole position tolerance is controlled within 0.015mm. The magnetic yoke keyway is machined using a gantry-type five-axis linkage CNC boring and milling machine. The closed-loop control of the machine tool spindle and tool path and the online measurement feedback compensation system ensure that the keyway symmetry, parallelism and position tolerance are all controlled within 0.02mm. The overall finishing process is carried out in a constant temperature workshop with the workshop temperature controlled at 20℃±1℃.

[0010] In the pre-assembly and matching step in the factory, the pin sleeve structure includes a first pin sleeve hole on the rotor support, a second pin sleeve hole on the main shaft, and a pin sleeve body.

[0011] The pin sleeve body is a cylindrical structure, and its outer diameter is interference-fitted with the first pin sleeve hole and the second pin sleeve hole. The interference is controlled between 0.005mm and 0.015mm, and the inner hole is used to pass through the coupling bolt. In the factory pre-assembly matching step, the specific content of the pre-assembly matching is to temporarily fix the rotor support and the main shaft through the pin sleeve body, use a dial indicator or laser tracker to detect radial runout and end face runout, ensure that the concentricity tolerance of the rotor support and the main shaft is within 0.03mm and the axial deviation is within 0.02mm / m, and number and mark each pin sleeve hole and the corresponding pin sleeve body, and record the measured fit data.

[0012] In the overall transportation and on-site hoisting steps, the rotor support adopts a horizontal deflection transportation method, that is, the disc plane of the rotor support is arranged at an angle to the direction of travel of the transport vehicle, so that the rotor support meets the clearance requirements of highway or railway transportation during transportation.

[0013] The present invention also provides an integrated rotor support, which is manufactured using the integrated rotor support manufacturing method described above. The integrated rotor support is an integral disc welding structure with an outer diameter greater than 5 meters. The central body and the support arm are an integral structure without on-site welding seams. The magnetic yoke keyway and pin sleeve hole of the integrated rotor support are all clamped and processed in the factory in one go, without welding or secondary processing on the construction site.

[0014] This invention discloses an integrated rotor support and its manufacturing method. By centralizing the integral welding, annealing heat treatment, and all machining processes of the rotor support in the manufacturing plant, it fundamentally eliminates the welding deformation problem caused by the on-site welding of the support arms and the central body of traditional segmented rotor supports. Furthermore, the machining accuracy of key features such as the magnetic yoke keyway and pin sleeve hole is directly guaranteed by a single clamping on a high-precision CNC machine tool in the factory, avoiding the loss of accuracy caused by welding deformation on-site and the need for secondary machining on-site. At the same time, by completing the pre-assembly matching of the rotor support and the spindle in the manufacturing plant, the concentricity and axis consistency of the rotor and the spindle are completely guaranteed by the machining accuracy and pre-assembly data in the factory, eliminating the connection deviations and safety hazards caused by the on-site drilling and reaming adjustment process, and significantly improving the operational reliability and long-term stability of the unit. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the manufacturing method of the integrated rotor support provided by the present invention.

[0017] Figure 2 This is a schematic diagram of the connection between the integrated rotor support and the main shaft provided by the present invention.

[0018] 101-Rotor bracket, 102-First pin hole, 103-Main shaft, 104-Second pin hole, 105-Pin body, 106-Coupling bolt. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] Please see Figure 1 and Figure 2 The present invention provides a method for manufacturing an integrated rotor support, the method comprising the following steps: S1. Integral welding: The rotor support 101 is integrally welded in the manufacturing plant. The rotor support 101 is a disc structure used in hydro-generator sets, and its outer diameter is greater than 5 meters. S2. Post-weld annealing: Annealing heat treatment is performed on the welded integral rotor support 101. S3. Overall precision machining: The annealed integral rotor support 101 is clamped and positioned in the manufacturing plant using a high-precision CNC machine tool to complete all machining processes of the rotor support 101. The machining processes include at least the machining of the magnetic yoke keyway and the pin sleeve hole. S4. Pre-assembly and matching in the factory: The rotor bracket 101 and the main shaft 103 are pre-assembled and matched in the manufacturing plant and connected and positioned by a pin sleeve structure. S5. Overall Transportation and On-site Lifting: The completed integrated rotor bracket is transported to the construction site and directly lifted into place.

[0021] In this embodiment, by centralizing the integral welding, annealing heat treatment, and all machining processes of the rotor support 101 within the manufacturing plant, the welding deformation problem caused by the traditional segmented rotor support 101 requiring on-site welding of the support arms and the central body is fundamentally eliminated. Furthermore, the machining accuracy of key features such as the magnetic yoke keyway and pin sleeve hole is directly guaranteed by a single clamping operation on a high-precision CNC machine tool in the factory, avoiding the loss of accuracy caused by on-site welding deformation and the need for secondary machining on-site. Simultaneously, by completing the pre-assembly matching of the rotor support 101 and the spindle 103 in the manufacturing plant, the concentricity and axial consistency of the rotor and the spindle 103 are fully guaranteed by machining accuracy and pre-assembly data in the factory, eliminating connection deviations and safety hazards caused by on-site drilling and reaming adjustments, significantly improving the unit's operational reliability and long-term stability.

[0022] Furthermore, in the overall welding forming step, the rotor support 101 is welded using a multi-layer multi-pass welding or narrow-gap submerged arc welding process. The preheating temperature before welding is 100°C to 150°C, the interpass temperature is controlled to be no higher than 200°C, and 100% ultrasonic flaw detection is performed after welding, so that the weld quality level reaches Grade 1.

[0023] In this embodiment, the rotor support 101 is made of low-alloy structural steel of Q345D or higher strength grade. The steel plate undergoes shot blasting after arrival at the factory to achieve a rust removal grade of Sa2.5. Before welding, the bevel and the area within 50mm on both sides are cleaned. Preheating is performed using flame heating or electric heating, with the preheating temperature controlled between 120℃ and 150℃. The interpass temperature is strictly controlled between 150℃ and 200℃. Narrow-gap submerged arc welding is performed using single-wire or multi-wire welding, with a wire diameter of 4.0mm to 5.0mm, a welding current of 480A to 550A, an arc voltage of 32V to 36V, and a welding speed of 25cm / min to 30cm / min. Slag removal is performed after each layer of welding, and the weld reinforcement of the capping layer is controlled between 1.5mm and 2.5mm. 100% ultrasonic testing is performed within 24 hours after welding, in accordance with the NB / T47013.3-2015 standard.

[0024] Furthermore, in the post-weld annealing step, the heating rate of the annealing heat treatment is controlled at 50℃ / h to 80℃ / h, the holding temperature is 550℃ to 620℃, the holding time is 2h to 4h, the cooling rate is controlled at 30℃ / h to 50℃ / h, and after cooling to below 200℃, the furnace is removed and air-cooled, and the residual stress relief rate is not less than 85%.

[0025] In this embodiment, the annealing heat treatment employs a large gas-fired trolley heat treatment furnace, with the effective heating zone size of the furnace chamber meeting the requirements for the overall loading of the rotor support 101. During loading, the rotor support 101 uses multi-point support to ensure no gravitational deformation occurs under hot conditions. During the heating stage, a segmented temperature control process is adopted: the heating rate is controlled at 50℃ / h below 300℃, and at 60℃ / h above 300℃. During the holding stage, the temperature difference within the furnace is controlled within ±10℃, and the holding temperature is selected as 580℃±10℃. The holding time is calculated based on the effective wall thickness of the workpiece; in this embodiment, the effective wall thickness is 80mm to 120mm, and the holding time is determined to be 3h to 4h. During the cooling stage, furnace-based cooling is adopted, with a cooling rate controlled at 40℃ / h. The furnace door is slightly opened to adjust the cooling rate, and the workpiece is removed from the furnace and air-cooled after the furnace temperature drops below 200℃. During the heat treatment process, 8 to 12 thermocouples are arranged at key locations such as the rotor support 101 hub, outer ring, and stiffeners to monitor temperature uniformity in real time. After treatment, residual stress was tested using the blind hole method or X-ray diffraction method, and the measured residual stress elimination rate reached 85% to 92%.

[0026] Furthermore, in the overall finishing process, the pin sleeve hole is machined using a boring die process. Through the guidance of the boring die and the cooperation of a high-precision boring machine, the diameter accuracy of the pin sleeve hole is guaranteed to reach H7 level, and the positional tolerance of the hole is controlled within 0.015mm. The magnetic yoke keyway is machined using a gantry-type five-axis linkage CNC boring and milling machine. Through the closed-loop control of the machine tool spindle 103 and the tool path and the online measurement feedback compensation system, the symmetry, parallelism and positional tolerance of the keyway are all controlled within 0.02mm. Moreover, the overall finishing process is carried out in a constant temperature workshop, with the workshop temperature controlled at 20℃±1℃.

[0027] In this embodiment, a heavy-duty CNC gantry milling machine or a CNC vertical turning and milling machining center with a table load capacity of over 200 tons and a stroke greater than 1.2 times the outer diameter of the rotor support 101 is selected. The rotor support 101 is aligned using the hub stop as a reference, employing a combination of an optical collimator and an electronic level. The parallelism between the reference plane and the table plane is ≤0.01mm, and the coaxiality between the center and the machine tool rotation center is ≤0.01mm. The magnetic yoke keyway is machined using a solid carbide T-slot cutter or a three-sided milling cutter. A roughing allowance of 0.5mm is left, a semi-finishing allowance of 0.15mm is left, and the finishing depth is 0.05mm to 0.10mm. The machine tool's online measurement system automatically measures the width and position after every two keyways machined, compensating for tool wear in real time. After machining, a coordinate measuring machine (CMM) was used for random inspection. In this embodiment, the measured keyway width tolerance was ±0.01mm, symmetry was 0.012mm, parallelism was 0.015mm, position accuracy was 0.018mm, and surface roughness was Ra1.2μm. The pin sleeve hole was machined using an integral circular boring die. The boring die material was QT600-3 or 45 steel, heat-treated, and then precision-machined after aging. The guide sleeve inner hole accuracy was H6 grade, and the clearance between the guide sleeve and the boring bar was 0.006mm to 0.008mm. The boring process consisted of three steps: rough boring, semi-finish boring, and finish boring. The finish boring allowance was 0.10mm to 0.15mm, the cutting speed was 80m / min to 100m / min, and the feed rate was 0.08mm / r to 0.12mm / r. In this embodiment, the measured pin sleeve hole diameter is φ80H7 (+0.03 / 0), with measured values ​​ranging from φ80.012mm to φ80.021mm. The maximum positional deviation is 0.011mm, the perpendicularity is 0.008mm, and the surface roughness Ra is 0.6μm to 0.8μm. The temperature in the constant temperature workshop is controlled at 20℃±1℃, and the relative humidity is 45% to 55%. The machine tool spindle 103 is preheated for more than 30 minutes, and finishing begins after thermal equilibrium is reached. After machining, a full-size 3D scan is performed using a laser tracker and compared with the design model. The pass rate for key dimensions is 100%, and the overall dimensional pass rate is over 99.5%.

[0028] Furthermore, in the factory pre-assembly matching step, the pin sleeve structure includes a first pin sleeve hole 102 provided on the rotor support 101, a second pin sleeve hole 104 provided on the main shaft 103, and a pin sleeve body 105.

[0029] The pin sleeve body 105 is a cylindrical structure. Its outer diameter is interference-fitted with the first pin sleeve hole 102 and the second pin sleeve hole 104. The interference is controlled between 0.005mm and 0.015mm. The inner hole is used to pass through the coupling bolt 106. In the factory pre-assembly matching step, the specific content of the pre-assembly matching is to temporarily fix the rotor support 101 and the main shaft 103 through the pin sleeve body 105, use a dial indicator or laser tracker to detect radial runout and end face runout, ensure that the concentricity tolerance of the rotor support 101 and the main shaft 103 is within 0.03mm and the axial deviation is within 0.02mm / m, and number and mark each pin sleeve hole and the corresponding pin sleeve body 105, and record the measured fit data.

[0030] In this embodiment, the pin body 105 is made of high-strength alloy steel such as 20CrMnTi or 40CrNiMoA. The blank is forged and then normalized, and after rough machining, it is carburized and quenched. The carburized layer depth is 1.0mm to 1.2mm, the surface hardness is HRC58 to 62, and the core hardness is HRC35 to 40.

[0031] Furthermore, in the overall transportation and on-site hoisting steps, the rotor support 101 adopts a horizontal deflection transportation method, that is, the disc plane of the rotor support 101 is arranged at an angle to the direction of travel of the transport vehicle, so that the rotor support 101 meets the clearance requirements of highway or railway transportation during transportation.

[0032] In this embodiment, a dedicated hydraulic rotatable transport bracket is used for the rotor support 101 with an outer diameter of 5.8m. The bracket is equipped with a slewing bearing mechanism and a two-stage tilt adjustment device. Before transportation, the rotor support 101 is hoisted onto the bracket, and the rotor support 101 is rotated 30° to 40° around the horizontal axis through the hydraulic system, so that its disc plane forms an angle of 35°±5° with the direction of travel of the transport vehicle. At this time, the projected size of the rotor support 101 in the width direction is 5.8m×sin35°≈3.33m, and the projected size in the height direction is 5.8m×cos35°≈4.75m. The bracket itself is 0.5m high, and the total height is approximately 5.25m. Through the two-stage tilt adjustment, the rotor support 101 is tilted as a whole by 10° to 15°, and the final transportation width is ≤4.8m and the transportation height is ≤4.4m, which fully meets the requirements for highway oversized transport permits.

[0033] The present invention also provides an integrated rotor support, which is manufactured using the integrated rotor support manufacturing method described above. The integrated rotor support is an integral disc welding structure with an outer diameter greater than 5 meters. The central body and the support arm are an integral structure without on-site welding seams. The magnetic yoke keyway and pin sleeve hole of the integrated rotor support are all clamped and processed in the factory in one go, without welding or secondary processing on the construction site.

[0034] In this embodiment, the integrated rotor support manufactured using the aforementioned integrated rotor support manufacturing method is a monolithic disc welded structure with an outer diameter greater than 5 meters. The central body and support arm are welded in the factory without any on-site welding seams, fundamentally eliminating the welding deformation and precision loss caused by on-site welding in traditional segmented structures. At the same time, key features such as the magnetic yoke keyway and pin sleeve hole are all completed in the factory through high-precision machining in a single clamping. The symmetry, parallelism, and positional tolerance of the keyway are stably controlled within 0.02mm, and the pin sleeve hole diameter accuracy reaches H7 level with a positional accuracy ≤0.015mm. This improves the precision of the rotor support 101 body by an order of magnitude compared to traditional on-site machining methods. In addition, no welding or secondary processing is required on-site, completely eliminating the one-month-long on-site keyway trimming and drilling and reaming process, allowing the rotor support 101 to be directly hoisted into place after arriving at the construction site.

[0035] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for manufacturing an integrated rotor support, characterized in that, Includes the following steps: Integral welding: The rotor support is integrally welded in the manufacturing plant. The rotor support has a disc-shaped structure and is used in hydro-generator sets. Its outer diameter is greater than 5 meters. Post-weld annealing: The welded integral rotor support is subjected to annealing heat treatment; Overall precision machining: The annealed integral rotor support is clamped and positioned in the manufacturing plant using a high-precision CNC machine tool to complete all machining processes of the rotor support. The machining processes include at least the machining of the magnetic yoke keyway and the pin sleeve hole. Pre-assembly and matching in the factory: The rotor support and the main shaft are pre-assembled and matched in the manufacturing plant, and connected and positioned by a pin sleeve structure; Overall transportation and on-site hoisting: The finished integrated rotor bracket is transported to the construction site and hoisted directly into place.

2. The manufacturing method of the integrated rotor support as described in claim 1, characterized in that, In the overall welding and forming step, the rotor support is welded using multi-layer multi-pass welding or narrow-gap submerged arc welding process. The preheating temperature before welding is 100℃ to 150℃, the interpass temperature is controlled not to exceed 200℃, and 100% ultrasonic flaw detection is performed after welding. The weld quality level reaches Grade 1.

3. The manufacturing method of the integrated rotor support as described in claim 2, characterized in that, In the post-weld annealing step, the heating rate of the annealing heat treatment is controlled at 50℃ / h to 80℃ / h, the holding temperature is 550℃ to 620℃, the holding time is 2h to 4h, the cooling rate is controlled at 30℃ / h to 50℃ / h, and after cooling to below 200℃, the furnace is removed and air-cooled, and the residual stress relief rate is not less than 85%.

4. The manufacturing method of the integrated rotor support as described in claim 3, characterized in that, In the overall finishing process, the pin sleeve hole is machined using a boring die process. Through the guidance of the boring die and the cooperation of a high-precision boring machine, the diameter accuracy of the pin sleeve hole is guaranteed to reach H7 level, and the positional tolerance of the hole is controlled within 0.015mm. The magnetic yoke keyway is machined using a gantry-type five-axis linkage CNC boring and milling machine. Through the closed-loop control of the machine tool spindle and tool path and the online measurement feedback compensation system, the symmetry, parallelism and positional tolerance of the keyway are all controlled within 0.02mm. The overall finishing process is carried out in a constant temperature workshop, with the workshop temperature controlled at 20℃±1℃.

5. The manufacturing method of the integrated rotor support as described in claim 4, characterized in that, In the factory pre-assembly and matching step, the pin sleeve structure includes a first pin sleeve hole on the rotor support, a second pin sleeve hole on the main shaft, and a pin sleeve body.

6. The manufacturing method of the integrated rotor support as described in claim 5, characterized in that, The pin sleeve body is a cylindrical structure, and its outer diameter is interference-fitted with the first pin sleeve hole and the second pin sleeve hole. The interference is controlled between 0.005mm and 0.015mm, and the inner hole is used to pass through the coupling bolt. In the factory pre-assembly matching step, the specific content of the pre-assembly matching is to temporarily fix the rotor support and the main shaft through the pin sleeve body, use a dial indicator or laser tracker to detect radial runout and end face runout, ensure that the concentricity tolerance of the rotor support and the main shaft is within 0.03mm and the axial deviation is within 0.02mm / m, and number and mark each pin sleeve hole and the corresponding pin sleeve body, and record the measured fit data.

7. The manufacturing method of the integrated rotor support as described in claim 6, characterized in that, In the overall transportation and on-site hoisting process, the rotor support adopts a horizontal deflection transportation method, that is, the disc plane of the rotor support is arranged at an angle to the direction of travel of the transport vehicle, so that the rotor support meets the clearance requirements of highway or railway transportation during transportation.

8. An integrated rotor support, manufactured using the method for manufacturing an integrated rotor support as described in claim 7, characterized in that, The integrated rotor support is an integral disc welded structure with an outer diameter greater than 5 meters. The central body and the support arm are an integral structure without on-site welding seams. The magnetic yoke keyway and pin sleeve hole of the integrated rotor support are all clamped and processed in the factory in one go, without welding or secondary processing on the construction site.

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