Method for machining split key pin hole of guide vane of water turbine through drilling machine

Abstract

The invention discloses a method for machining a split key pin hole of a guide vane of a water turbine through a drilling machine. The machining method mainly comprises the steps that the guide vane, a guide vane arm and a connecting plate are assembled, aligned and pressed, a drilling machine aligns according to the position of a machining line of the split key pin hole of the guide vane, and the split key pin hole is machined through the technological methods of trial machining, two-time drilling, two-time reaming and one-time reaming. Generally, the average number of the split key pin holes of the guide vane of one hydroelectric generating set can reach 50, the machining period of a numerical control boring machine is long, the invention provides a method for high-precision machining of the split key pin holes of the guide vane of the water turbine by using a drilling machine instead of the boring machine, the production scheduling pressure of the numerical control boring machine in a workshop is relieved, and the machining efficiency is improved on the premise that the machining precision of the split key pin holes is guaranteed. And the machining and using cost of a numerical control machine tool is saved, and the method has the advantages of being easy to operate, high in universality and the like and can be suitable for machining the guide vane split key pin hole of the hydroelectric generating set.

Description

Technical Field

[0001] The invention relates to the field of mechanical processing of a water turbine generator set, and in particular to a method for processing a split-petal key pin hole of a water turbine guide vane using a drilling machine. Background Art

[0002] The turbine guide vane split key is a key component in the water guide mechanism used to connect the guide vane shaft diameter and the guide vane arm to transmit the torque of the relay mechanism and realize the switching action of the movable guide vane. Usually, the number of guide vanes in a hydropower unit ranges from 16 to 24, and the number of split key pin holes for each guide vane is 2 to 3, that is, the average number of split key pin holes for each unit is 50. When using a CNC boring machine for processing, due to the large number of pin holes and high surface accuracy requirements, and the split key pin holes are slender holes with a length-to-diameter ratio greater than 4.5 times, the processing is difficult, resulting in a long processing cycle of the CNC boring machine. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a method for high-precision machining of the key pin hole of the guide vane of a turbine using a drilling machine instead of a boring machine, which is simple to operate, has strong versatility and reduces costs. The technical solution of the present invention is as follows:

[0004] S1. When machining the guide vane, guide vane arm and connecting plate individually, the center line of the design drawing shall be marked on the surface of the workpiece, which will serve as the basis for the relative angles between the guide vane, guide vane arm and connecting plate when machining the key pin holes of the petals later;

[0005] S2, the guide vane, the guide vane arm and the connecting plate are assembled according to the center line engraved on the single piece to form an assembly;

[0006] S3. According to the drawing, mark the pin hole positions of the petal keys, and draw the pin hole processing lines and inspection lines on the assembly;

[0007] S4. Place the jig on the drilling machine processing platform;

[0008] S5. Lift the assembly above the mold;

[0009] S6. Align the lower shaft diameter of the guide vane with the shaft hole of the mold and assemble vertically;

[0010] S7, a pressing plate I, a supporting tube I, a locking nut I, and a T-screw I constitute a pressing plate tool I;

[0011] S8, a pressing plate II, a supporting tube II, a locking nut II, and a T-screw II constitute a pressing plate tool II;

[0012] S9, a pressing plate III, a supporting tube III, a locking nut III, and a T-screw III constitute a pressing plate tool III;

[0013] S10, using the pressing plate tool I and the pressing plate tool II to press the guide vane at both sides of the guide vane body;

[0014] S11. Use the pressing plate tool III to assemble the adjusting plate and press it on the plane of the connecting plate;

[0015] S12. Use adjusting screws Ⅰ and Ⅱ to adjust the angles of the connecting plate, the guide vane arm and the center line of the guide vane body to the theoretical angles required by the design drawings;

[0016] S13. Use a level gauge to level the upper end surface of the guide vane to within 0.02 mm;

[0017] S14, lock the adjusting screws Ⅰ and Ⅱ on both sides;

[0018] S15. Use the pressing plate tool III to press the assembly on the connecting plate plane;

[0019] S16. Check the upper end surface of the guide vane to see if it is level.

[0020] S17, align the drilling machine according to the position of the guide vane key pin hole processing line;

[0021] S18, test the pin hole of the split key, drill a shallow pit according to the position of the pin hole processing line, and check that the position of the shallow pit should be consistent with the sight line;

[0022] S19, machining the bottom hole of the split key pin hole;

[0023] S20, processing and expanding the split key pin hole;

[0024] S21, processing and reaming of split key pin holes;

[0025] S22, clean the split key pin holes, and clean the guide vanes, guide vane arms, and connection plate surfaces;

[0026] S23. Check the surface roughness of the split key pin hole and measure the pin hole diameter with an internal diameter micrometer;

[0027] S24. Remove the pressure plate tool I, pressure plate tool II, and pressure plate tool III, loosen the adjusting screw I and adjusting screw II, and lift the assembly away from the work station.

[0028] Furthermore, in S13, the upper end surface of the guide vane is leveled by using a coincidence level to adjust the upper end surface level to within 0.02 mm.

[0029] Furthermore, in S19, the bottom hole is drilled twice. The first time, a drill bit with a diameter in the range of 0.5 to 0.7 times of the split key pin hole diameter is used to drill the bottom hole. The second time, a drill bit with a diameter in the range of 0.87 to 0.93 times of the split key pin hole diameter is used to drill the bottom hole. At this time, the surface roughness of the bottom hole reaches 12.5 μm-6.3 μm.

[0030] Furthermore, in S20, the hole expansion is performed twice, with a 0.2mm-0.3mm margin on one side being left for the first hole expansion and a 0.1mm-0.15mm margin on one side being left for the second hole expansion, and at this time, the surface roughness of the expanded hole reaches 3.2μm.

[0031] Furthermore, in S21, the pin hole is reamed once to the pin hole diameter size requirement of the drawing, and the surface roughness of the pin hole can reach 1.6 μm.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. By making simple tooling, an ordinary drilling machine can be used instead of a CNC boring machine to complete the processing of the turbine guide vane split key pin holes. In the early tests, the pin hole processing process and cutting parameters were continuously optimized, and a relatively complete drilling machine processing technology for split key pin holes was summarized. The effect was significant in subsequent practical applications. Under the premise of ensuring the processing quality and efficiency of difficult and long holes with a length-to-diameter ratio greater than 4.5 times, the diameter tolerance and surface roughness of the split key pin holes can meet the high-precision requirements of the drawings, effectively solving the problem that the workshop's processing of the guide vane split key pin holes has always occupied the use cycle of the CNC boring machine, and alleviating the production scheduling pressure of the workshop's CNC boring machine.

[0034] 2. The present invention is simple to operate and has strong versatility, which saves the cost of using CNC machine tools for processing, and can be widely used in the processing of key pin holes of guide vanes of all types of hydropower units. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a front view schematic diagram of machining a turbine guide vane split key pin hole by a drilling machine.

[0036] Figure 2 The AA cross-sectional schematic diagram is a front view schematic diagram of a drilling machine for machining a split key pin hole of a turbine guide vane according to the present invention.

[0037] Explanation of the numbers in the figure: 1-drilling machine; 2-platform; 3-support rod Ⅰ; 4-T-screw Ⅰ; 5-pressure plate Ⅰ; 6-locking nut Ⅰ; 7-mold; 8-guide vane; 9-T-screw Ⅱ; 10-support rod Ⅱ; 11-pressure plate Ⅱ; 12-locking nut Ⅱ; 13-T-screw Ⅲ; 14-support rod Ⅲ; 15-pressure plate Ⅲ; 16-adjusting plate; 17-locking nut Ⅲ; 18-connecting plate; 19-split key pin hole; 20-guide vane arm; 21-adjusting screw Ⅰ; 22-adjusting screw Ⅱ. DETAILED DESCRIPTION

[0038] Taking the processing of the split key pin holes of the guide vanes of a pumped storage hydropower unit of a hydropower station as an example, the process of processing by the method of the present invention is explained: the guide vanes, guide vane arms, and connecting plates of the turbine of the unit have been finely processed, and the next step is to assemble and drill the split key pin holes of the guide vanes and guide vane arms. The guide vanes weigh 2140KG, are 2.86M long, and are made of ZG04Cr13Ni5Mo. The guide vane arms are made of ZG20Mn. After being assembled with the guide vane arms and connecting plates, the total weight is about 2700KG. Each set of guide vane split key pin holes is 2-Φ70 (+0.03,0), the effective depth of the pin holes is 320mm, and the roughness is 1.6μm. It is a typical slender hole with a relatively difficult processing and a length-to-diameter ratio greater than 4.5 times.

[0039] Specific implementation method 1: refer to Figure 1 and Figure 2 This embodiment is described. This embodiment provides a method for machining a turbine guide vane split key pin hole by a drilling machine. The method is implemented by the following steps:

[0040] S1, guide vane 8, guide vane arm 20, connecting plate 18 are processed as a single piece, and the center line position of the design drawing is engraved on the workpiece surface, which serves as the basis for the guide vane 8, guide vane arm 20, and connecting plate 18 to be assembled into a relative angle when the petal key pin hole is subsequently processed;

[0041] S2, the guide vane 8 and the guide vane arm 20, the connecting plate 18 are assembled according to the center line engraved on the single piece to form an assembly;

[0042] S3. According to the theoretical position of the petal key pin hole 19 in the drawing, draw the pin hole processing line and the inspection line on the assembly;

[0043] S4, placing a jig 7 on the processing platform 2 of the drilling machine 1;

[0044] S5, lifting the assembly to above the mold 7;

[0045] S6, align the lower shaft diameter of the guide vane 8 with the shaft hole of the mold 7 and assemble vertically;

[0046] S7, pressing plate Ⅰ5, supporting tube Ⅰ3, locking nut Ⅰ6, T-screw Ⅰ4 constitute pressing plate tool Ⅰ;

[0047] S8, pressing plate II 11, supporting tube II 10, locking nut II 12, and T-screw II 9 constitute pressing plate tool II;

[0048] S9, pressing plate III 15, supporting tube III 14, locking nut III 17, and T-screw III 13 constitute pressing plate tool III;

[0049] S10, using the pressing plate tool I and the pressing plate tool II to press the guide vane at both sides of the guide vane body;

[0050] S11, using the pressing plate tool III to assemble the adjusting plate 16 and press it on the plane of the connecting plate 18;

[0051] S12, using adjusting screws I 21 and II 22 to adjust the angles of the connecting plate 18, the guide vane arm 20 and the center line of the guide vane 8 to the theoretical angle required by the design drawing;

[0052] S13, use the image level to level the upper end surface of the guide vane 8 to within 0.02 mm;

[0053] S14, lock the adjusting screws Ⅰ21 and Ⅱ22 on both sides;

[0054] S15, using the pressing plate tool III to press the assembly on the plane of the connecting plate 18;

[0055] S16, recheck the level of the upper end surface of the guide vane 8 to see if it is qualified;

[0056] S17, align the drilling machine according to the position of the processing line of the key pin hole 19 of the guide vane 8;

[0057] S18, test-drill the split key pin hole 19, drill a shallow pit according to the pin hole processing line, visually check whether the shallow pit position is correct, and continuously correct the deviation until the shallow pit position is concentric with the sight line. The feed rate during test drilling is less than the normal feed rate to ensure that the drill bit does not deviate;

[0058] S19, machining the bottom hole of the split key pin hole 19;

[0059] S20, processing and enlarging the split key pin hole 19;

[0060] S21, processing and reaming the split key pin hole 19;

[0061] S22, cleaning the petal key pin hole 19, and cleaning the surfaces of the guide vane 8, the guide vane arm 20 and the connecting plate 18;

[0062] S23, check the surface roughness of the split key pin hole 19 and measure the pin hole diameter with an internal diameter micrometer;

[0063] S24. Remove the pressure plate tool I, pressure plate tool II, and pressure plate tool III, loosen the adjusting screw I21 and adjusting screw II22, and lift the assembly away from the workstation.

[0064] In the present embodiment, a method is implemented that can use a drilling machine instead of a boring machine to high-precision process the guide vane key pin holes of a turbine, which can effectively solve the problem that the processing of the guide vane key pin holes has always occupied the use cycle of the CNC boring machine, alleviate the production scheduling pressure of the CNC boring machine in the workshop, and save the processing and use costs of CNC machine tools while ensuring the processing accuracy of the petal key pin holes. It has the characteristics of simple operation and strong versatility, and can be applied to the processing of the guide vane key pin holes of all types of hydropower units.

[0065] Specific implementation method 2: refer to Figure 1 and Figure 2 This embodiment is described as further limiting S13 described in the first embodiment. In this embodiment, the upper end surface of the guide vane 8 is adjusted to be level in S13, and a coincidence level is used to adjust the upper end surface level to within 0.02 mm.

[0066] In this embodiment, leveling the upper end surface of the guide vane is a key process before the subsequent processing of the split key pin hole. The leveling accuracy is high, which ensures the verticality of the split key pin hole and is more conducive to the drilling, expanding and reaming of the pin hole.

[0067] Specific implementation method three: refer to Figure 1 and Figure 2 To explain this embodiment, this embodiment further limits the S19 described in the specific embodiment 1. In this embodiment, the bottom hole in S19 is drilled twice. The first time, a Φ46 high-speed steel drill is used to drill the bottom hole. The drilling depth is 335 mm. The cutting parameters are: Vc﹤20 m / min, F=0.2-0.3 mm / r. The second time, a Φ64 high-speed steel drill is used to drill the bottom hole. The drilling depth is 335 mm. The cutting parameters are: Vc﹤15 m / min, F=0.2-0.3 mm / r. At this time, the surface roughness of the bottom hole is 6.3 μm. When drilling deep holes, the drilling depth of the drill bit reaches twice the diameter, the drill is withdrawn once for chip removal, and cooling and lubrication are added.

[0068] Specific implementation method 4: refer to Figure 1 and Figure 2 To explain this embodiment, this embodiment further limits the S20 described in the specific embodiment 1. In this embodiment, the hole expansion in S20 is carried out twice. The first hole expansion is to Φ69.5mm, the hole expansion depth is 335mm, and the cutting parameters are: Vc=8m / min-14m / min, F=0.5-0.6mm / r. The second hole expansion is to Φ69.7mm, the hole expansion depth is 335mm, and the cutting parameters are: Vc=8m / min-14m / min, F=0.5-0.6mm / r. At this time, the surface roughness of the expanded hole is 3.2μm.

[0069] In implementation mode three and implementation mode four, through two drilling and two reaming operations, the cutting parameters are strictly controlled so that the allowance before reaming is controlled within an appropriate range and the surface has a small roughness, providing good processing conditions for the last reaming process and ensuring the surface quality after reaming.

[0070] Specific implementation method five: refer to Figure 1 and Figure 2To explain this embodiment, this embodiment further limits the S21 described in the specific embodiment 1. In this embodiment, the hole is reamed in S21, and the hole is reamed to the pin hole diameter size requirement of 70 (+0.03, 0) in one time, the hole expansion depth is 320mm, the cutting parameters are: Vc=1.2m / min-5m / min, F=0.8-0.9mm / r, and the pin hole surface roughness is 1.6μm.

[0071] In implementation modes one to five, the specified cutting parameters are a set of cutting parameters suitable for drilling, expanding, and reaming slender pin holes, which are obtained through multiple processing tests in the early stage using a fixed drilling machine and similar workpiece materials. If the machine tool, workpiece material, and hole diameter size are changed, the present implementation mode is used as a reference for testing, and slight adjustments are made according to the actual pin hole processing conditions to obtain the most suitable process flow and cutting parameters for one's own equipment and products.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for drilling a turbine guide vane split key pin hole, the method comprising the following steps: S1, when the guide vane (8), the guide vane arm (20), and the connecting plate (18) are processed individually, a line is engraved on the surface of the workpiece according to the center line position of the design drawing, which serves as a basis for the guide vane (8), the guide vane arm (20), and the connecting plate (18) to be assembled at a relative angle when the split key pin hole is subsequently processed; S2, the guide vane (8) and the guide vane arm (20) and the connecting plate (18) are assembled according to the center line engraved on the single piece to form an assembly; S3. According to the position of the split key pin hole (19) in the drawing, draw the pin hole processing line and the inspection line on the assembly; S4, placing a mold (7) on a processing platform (2) of a drilling machine (1); S5, lifting the assembly to above the mold (7); S6, align the lower axial diameter of the guide vane (8) with the axial hole of the mold (7) for vertical assembly; S7, a pressing plate I (5), a supporting tube I (3), a locking nut I (6), and a T-screw I (4) constitute a pressing plate tool I; S8, a pressing plate II (11), a supporting tube II (10), a locking nut II (12), and a T-screw II (9) constitute a pressing plate tool II; S9, a pressing plate III (15), a supporting tube III (14), a locking nut III (17), and a T-screw III (13) constitute a pressing plate tool III; S10, using the pressing plate tool I and the pressing plate tool II to press the guide vane at both sides of the guide vane body; S11, using the pressing plate tool III to assemble the adjusting plate (16) and press it onto the plane of the connecting plate (18); S12, using adjusting screw rod I (21) and adjusting screw rod II (22), adjusting the angles of the connecting plate (18), the guide vane arm (20) and the center line of the guide vane (8) to the theoretical angle required by the design drawing; S13, leveling the upper end surface of the guide vane (8) to be horizontal; S14, tighten the adjusting screws Ⅰ (21) and Ⅱ (22) on both sides; S15, using a pressing tool III to press the assembly on the plane of the connecting plate (18); S16, recheck the level of the upper end surface of the guide vane (8) to see if it is acceptable; S17, aligning the drilling machine according to the position of the processing line of the key pin hole (19) of the guide vane (8); S18, trial processing of the split key pin hole (19), drilling a shallow pit according to the position of the pin hole processing line, and checking that the position of the shallow pit should be consistent with the sight line; S19, machining the bottom hole of the split key pin hole (19); S20, processing and expanding the split key pin hole (19); S21, processing the split key pin hole (19) by reaming; S22, cleaning the split key pin hole (19), cleaning the surfaces of the guide vane (8), the guide vane arm (20) and the connecting plate (18); S23, check the surface roughness of the split key pin hole (19) and measure the pin hole diameter with an internal diameter micrometer; S24. Remove the pressure plate tool I, pressure plate tool II, and pressure plate tool III, loosen the adjusting screw rod I (21) and adjusting screw rod II (22), and lift the assembly away from the work station.

2. The method for machining a turbine guide vane split key pin hole by a drilling machine according to claim 1, characterized in that: In the above S13, the upper end surface of the leveling guide vane (8) is adjusted to a level within 0.02 mm using a level gauge.

3. The method for machining a turbine guide vane split key pin hole by a drilling machine according to claim 1, characterized in that: In S19, the bottom hole is drilled twice. The first time, a drill bit with a diameter in the range of 0.5 to 0.7 times the diameter of the split key pin hole (19) is used to drill the bottom hole. The second time, a drill bit with a diameter in the range of 0.87 to 0.93 times the diameter of the split key pin hole (19) is used to drill the bottom hole. At this time, the surface roughness of the bottom hole reaches 12.5 μm to 6.3 μm.

4. The method for machining a turbine guide vane split key pin hole by a drilling machine according to claim 1, characterized in that: In S20, the hole is expanded twice, with a 0.2mm-0.3mm margin on one side being left for the first expansion, and a 0.1mm-0.15mm margin on one side being left for the second expansion. At this time, the surface roughness of the expanded hole reaches 3.2μm.

5. The method for machining a turbine guide vane split key pin hole by a drilling machine according to claim 1, characterized in that: In S21, the hole is reamed once to the pin hole diameter size requirement of the drawing, and the surface roughness of the pin hole reaches 1.6 μm.

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