A processing method of a large-flow supercharger turbine shaft

Abstract

The application discloses a machining method of a large-flow supercharger turbine shaft, improves machining and manufacturing efficiency of the turbine shaft, and reduces production cost in batch production. The machining method of the large-flow supercharger turbine shaft comprises the following steps: S1, machining a welded light shaft blank to obtain a welded light shaft; S2, machining a welded turbine disc blank to obtain a welded turbine disc; S3, adopting friction welding to assemble and weld the welded light shaft and the welded turbine disc to obtain a welded turbine shaft; and S4, machining the welded turbine shaft to obtain a turbine shaft finished product.

Description

Technical Field

[0001] This invention relates to the field of marine turbocharger manufacturing and processing technology, and in particular to a processing method for a high-flow turbocharger turbine shaft. Background Technology

[0002] A turbocharger is a control device that uses exhaust gas to drive a rotor, compressing and pushing more air into the combustion chamber, thereby increasing the engine's output power. The turbine shaft, as one of the key components of the rotor, primarily functions to transmit torque. In recent years, with changes in the international landscape, to meet the shipbuilding industry's demand for large-bore, high-flow marine low-speed engine turbochargers, breakthroughs and innovations in key technologies are needed, along with their mastery and application. This will improve manufacturing efficiency, reduce production costs, meet changing market demands, and solidify market competitiveness.

[0003] The turbine shaft structure of a large-bore, high-flow marine low-speed turbocharger is significantly larger than existing products, with the turbine disk supporting it having an overhanging structure and the center of gravity of the parts concentrated at one end, resulting in a top-heavy distribution. The turbine shaft structure includes multiple shaft diameters, a turbine disk, and a triangular prism. The turbine disk has evenly distributed tree-shaped tenons on its circumference for assembling turbine blades. The symmetrical center line of the tenon and the axis of the turbine disk form a certain angle, and the intersection of the two lines is on the turbine disk. This intersection is the design center of the tenon and has a precise positional relationship on the turbine disk. This type of structure typically has high requirements, is complex, and is extremely difficult to manufacture. The machining accuracy and quality of the turbine shaft tenons directly affect the basic performance of the turbocharger, such as airflow and working pressure ratio, as well as its service life.

[0004] There are three main methods for machining the tenon grooves of turbine shafts: broaching, milling, and wire EDM. In terms of machining results, broaching and milling produce better surface finishes than wire EDM. In terms of machining efficiency, broaching is more efficient than milling, and milling is more efficient than wire EDM. Broaching offers high manufacturing efficiency and is often used for mass production.

[0005] The following challenges exist in the manufacturing and machining of turbine shafts for this type of large-bore, high-flow marine low-speed turbocharger:

[0006] (1) The turbine shaft has a special structure. The pressure end has a long journal section, while the turbine disk back of the vortex end has only a convex circle. The center of gravity is concentrated on one side, resulting in a top-heavy distribution. The structural size is several times larger than that of existing mature products. The symmetrical center line of the tenon groove is at a certain angle to the axis of the turbine disk. During broaching, the forces on both sides are uneven and change greatly, making it easy to rotate. If the long journal end of the pressure end is selected for positioning and clamping during the machining of the turbine shaft tenon groove, the connection space of the machine tool equipment cannot avoid the journal of the pressure end of the turbine shaft. If the vortex end positioning and clamping is used, there is no reliable and firm connection and fixing structure, and there is no way to prevent rotation and limit the position. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a machining method for a high-flow turbocharger turbine shaft, which improves the machining and manufacturing efficiency of the turbine shaft and reduces production costs for mass production.

[0008] The objective of this invention is achieved as follows:

[0009] A method for machining a high-flow-rate turbocharger turbine shaft includes the following steps:

[0010] S1. Machining the welding optical shaft blank to obtain the welding optical shaft;

[0011] S2. Machining the welded turbine disk blank to obtain the welded turbine disk;

[0012] S3. The welding optical shaft and the welding turbine disk are assembled by friction welding to obtain the welded turbine shaft;

[0013] S4. Machining and welding the turbine shaft to obtain the finished turbine shaft.

[0014] Further, step S1 includes:

[0015] S110 rough turning: Take the welding shaft blank, clamp the outer circle with a three-jaw chuck, align it, rough turn one end to remove the blank allowance, and process it to the position without leaving any allowance.

[0016] S120 rough turning: Turn around, use the three-jaw chuck to turn the outer diameter, align, rough turn the other end to remove the blank allowance, and process to the desired position without leaving any allowance to obtain the welded optical shaft.

[0017] Further, step S2 includes:

[0018] S210 rough turning: Take the welded turbine disk blank, clamp the outer circle with a three-jaw chuck, align it, rough turn one end to remove the large allowance of the blank, and leave a 1mm allowance on the end face and the outer circle.

[0019] S220 rough turning: Turn around, use the three-jaw chuck to machine the outer diameter, bring it to the flat end face, align the machined outer diameter, rough turn the other end to remove the large amount of blank material, leave 1mm allowance on the end face and outer diameter respectively.

[0020] S230 precision machining: use a soft three-jaw chuck to clamp the outer diameter, align the outer diameter and the runout of the machined end face to within 0.05mm, and precision machine the scroll end;

[0021] S240 precision machining: Clamp the outer diameter with a soft three-jaw chuck, align the machined outer diameter and the runout of the machined end face to within 0.03mm, and precision machine the pressing end to obtain the welded turbine disk.

[0022] Further, step S3 includes:

[0023] S310 welding: a. Take the welding turbine disk and welding optical shaft, clean and dry their respective welding surfaces; b. Perform friction welding on the first piece;

[0024] S320 heat treatment: Stress-free annealing is performed on the welded turbine shaft after friction welding to eliminate the welding stress on the welded turbine shaft and avoid stress affecting the strength of friction welding.

[0025] S330 machine: The outer circle of the turbine shaft weld is welded for the first piece of machining and welding, which facilitates weld flaw detection;

[0026] S340 flaw detection: Penetrant testing is performed on the first welded piece, and cracks and defects are not allowed to be detected.

[0027] S350 wire cutting: Four tensile test specimens were cut from the cross section of each welded turbine shaft. The four tensile test specimens were evenly distributed at 90° on the cross-sectional circumference of the friction weld point and were located at the middle of the cross-sectional circumference of the friction weld point.

[0028] S360 lathe: Turn the sample dimensions to the required size;

[0029] S370 inspection: Inspect the strength of the friction weld point of the first piece welded, including tensile strength, yield strength, and elongation;

[0030] If all four tensile test specimens pass the test, repeat steps S310-S320 for mass production; if they fail, repeat steps S310-S370.

[0031] Further, step S4 includes:

[0032] S410 rough turning: a. Take the finished welded turbine shaft, clamp the outer diameter with a three-jaw chuck, hold the end face, align the outer diameter and end face of the turbine disk, ensuring the runout is no more than 0.03mm, and finish the outer diameter of the turbine shaft pressure end section; b. Set up a center frame, turn the total length to the required dimensions, and drill the center hole for the turbine shaft pressure end; c. Remove the center hole, remove the center frame, and turn the outer diameters and steps of each section of the turbine shaft pressure end to the required dimensions.

[0033] S420 rough turning: turn around, use a three-jaw chuck to check the outer diameter, set up a center rest, align the outer diameter of the turbine disk, ensure the end face runout is no more than 0.05mm, machine the outer diameter of the turbine disk and the end face of the turbine end, and drill the center hole of the turbine shaft end.

[0034] S430 grinder: Double center clamping, rough grinding the outer diameter of the turbine disk, the end face of the turbine end, and the two reference circles of the turbine shaft pressure end, which are used for clamping and alignment references in subsequent fine turning processes.

[0035] S440 precision machining: soft three-jaw chuck turbine disk outer circle, end face close to flat, top center hole, recalibrate S430 process two gear reference circle ground, runout no more than 0.02mm, precision machining pressing end;

[0036] S450 precision machining: Turn around, use a soft three-jaw clamp to clamp the outer diameter, attach the center support to the center hole, align the already machined outer diameter and ensure the runout of the turbine disk end face is no more than 0.05mm, and precision machine the turbine end;

[0037] S460 inspection: Penetrant testing is performed on the turbine shaft welds, and no cracks or defects are allowed.

[0038] S470 heat treatment: High-frequency quenching is performed on the quenching location of the turbine shaft;

[0039] S480 lathe: On the lathe, use carbide tips to grind the center holes at both ends of the turbine shaft to repair the center holes that were scratched or roughened during turning and inspection, thereby ensuring the reliability of the grinding and clamping reference in subsequent processes.

[0040] S490 grinder: Double center clamping, for precision grinding of the outer diameter and end face of each grade to the required standard;

[0041] S4100 CNC milling: Use a soft three-jaw chuck to clamp the outer diameter of the turbine disk, top center hole, recalibrate the turbine disk end face and bearing stop reference runout to be no more than 0.015mm, and mill the triangular pyramid to the required size;

[0042] S4110 clamps: Fit the tapered protective sleeve onto the triangular pyramidal part after the S4100 process;

[0043] S4120 precision machining: Clamp the outer diameter of the turbine disc with a soft three-jaw chuck, set up a center support, align the bearing stop reference outer diameter, and ensure the runout is no more than 0.02mm. Precision machine the end thread and hole of the turbine shaft pressure end to the requirements.

[0044] S4130 Inspection: Penetrant testing is performed on the turbine shaft pressure end, turbine end bearing, and thrust bearing. Cracks and defects are not allowed to be detected.

[0045] S4140 CNC milling: After aligning the outer circle runout of the turbine disk step to no more than 0.02mm, mill the U-shaped positioning groove to the required size;

[0046] S4150 broaching: Broach the tenon to the required size;

[0047] S4160 grinder: Double center clamping, grinding to remove burrs from the end face of the wheel disc after broaching the tenon groove;

[0048] S4170 precision machining: Clamp the outer circle with a soft three-jaw chuck, set up a center support, align the bearing stop reference circle with a runout of no more than 0.01mm, then precision machine, and polish away the quenching induction color at the quenching position.

[0049] S4180 pliers: Deburr and remove the tapered protective sleeve.

[0050] Furthermore, in the S450 process, an external thread is precision machined on the outer circle of the turbine disc journal. The external thread is used for subsequent tenon and groove broaching for connection and fixation.

[0051] A process boss is provided on the inner ring of the turbine disk back. In process S4140, a U-shaped positioning anti-rotation groove is milled on the process boss. The U-shaped anti-rotation groove is used in subsequent mortise and tenon broaching processes to prevent rotation and limit the rotation in conjunction with the turbine shaft mortise and tenon broaching tool.

[0052] In the S4170 process, the process mounts, process bosses, and internal threaded holes are machined to the required specifications by turning.

[0053] Further, step S1 includes S130 precision machining: take a new welding shaft blank, clamp it with a three-jaw chuck, align it, machine a high-frequency quenched test bar, turn the two ends over and machine it to obtain a turbine shaft high-frequency quenched test bar, requiring the structure of the test bar to be consistent with the journal structure of the turbine shaft.

[0054] In the S470 process, a test bar is first used for trial processing. After the test is qualified and meets the requirements, the turbine shaft quenching position is then subjected to high-frequency quenching.

[0055] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0056] Due to the special nature of the component structure, and addressing the difficulties in machining the turbine shaft of the large-diameter, high-flow marine low-speed turbocharger, the present invention aims to overcome the shortcomings of existing technologies and provide a new turbine shaft machining method using the company's equipment. By setting a process boss on the inner ring of the turbine disk vortex end wheel back and milling a U-shaped groove, and setting a sufficient process allowance on the outer circle of the vortex end wheel shaft end and precision machining an M85x3 external thread as a process connection and fixing latch, the invention successfully solves the problems of difficult positioning and clamping, and lack of a firm and reliable positioning, connection, and anti-rotation limiting structure when broaching the tenon groove of the turbine shaft of the large-flow turbocharger.

[0057] This invention also provides a detailed and comprehensive process for the turbine shaft of a large-diameter, high-flow marine low-speed engine turbocharger, employing friction welding and tenoning broaching, thus filling the gaps and deficiencies in the existing technology.

[0058] This invention, through methodological innovation and rational design of the process sequence, successfully solves the problems of difficult positioning and clamping, and lack of a firm and reliable positioning, connection, and fixing structure when broaching the tenon groove of the turbine shaft of a large flow turbocharger by setting a process boss and milling a U-shaped groove on the inner ring of the turbine end wheel back, and setting an M85x3 external thread with sufficient process allowance on the outer circle of the turbine end wheel shaft as a process connection and fixing bracket. This significantly improves the processing and manufacturing efficiency of the turbine shaft and reduces production costs for mass production.

[0059] This invention also provides a detailed and comprehensive process for the turbine shaft of a large-diameter, high-flow marine low-speed engine turbocharger, employing friction welding and tenoning broaching, thus filling the gaps and deficiencies in the existing technology. Attached Figure Description

[0060] Figure 1 Schematic diagram of turbine shaft assembly structure;

[0061] Figure 2 Schematic diagram of turbine shaft structure;

[0062] Figure 3 Schematic diagram of the welding optical axis blank structure;

[0063] Figure 4 Schematic diagram of the welded optical axis structure;

[0064] Figure 5 Schematic diagram of the welded turbine disk blank structure;

[0065] Figure 6 Schematic diagram of welded turbine disk structure;

[0066] Figure 7 Schematic diagram of welded turbine shaft structure;

[0067] Figure 8 Method flowchart;

[0068] Figure 9 Attached diagram for welding optical axis step 10;

[0069] Figure 10 Attached diagram for welding optical axis 20;

[0070] Figure 11 Attached diagram for welding optical axis 30;

[0071] Figure 12 Attached diagram for step 10 of welding the turbine disk;

[0072] Figure 13 Attached diagram for welding turbine disk step 20;

[0073] Figure 14 Attached diagram for welding turbine disk step 30;

[0074] Figure 15 Attached diagram for welding turbine disk step 40;

[0075] Figure 16 Attached diagram for turbine shaft 10 process;

[0076] Figure 17 Attached diagram for turbine shaft 20 process;

[0077] Figure 18 Attached diagram for turbine shaft 30 process;

[0078] Figure 19 Attached diagram for turbine shaft 40 process;

[0079] Figure 20 Attached diagram for turbine shaft 50 process;

[0080] Figure 21 Attached diagram for turbine shaft 90 process;

[0081] Figure 22 Attached diagram for turbine shaft 120 process;

[0082] Figure 23 Attached diagram showing the process of turbine shaft 140;

[0083] Figure 24 Attached diagram showing the process of turbine shaft 170;

[0084] Figure 25 Schematic diagram of clamping and positioning symbols. Detailed Implementation

[0085] A method for processing a turbine shaft of a high-flow turbocharger, the process is as follows: (1) Processing a welded optical shaft blank to obtain a welded optical shaft; (2) Processing a welded turbine disk blank to obtain a welded turbine disk; (3) Welding the welded optical shaft and the welded turbine disk together by friction welding to obtain a welded turbine shaft; (4) Processing the welded turbine shaft to obtain a turbine shaft.

[0086] Specific process steps:

[0087] S1. Welding optical shaft machining process steps: Using... Figure 3 The forged welded shaft blank shown is processed according to the following flow: 10 rough turning → 20 rough turning → 30 finish turning → 40 clamping. The specific process steps are as follows:

[0088] 1) 10 Rough turning: Clamp the outer diameter with a three-jaw chuck, align, and press... Figure 9 In the attached diagram of the 10th process of welding the optical shaft, one end is rough-machined to remove the blank allowance, and the machining is completed without leaving any allowance.

[0089] 2) 20 rough turning: Turn around, use the three-jaw chuck to turn the outer diameter, align, and press... Figure 10 In the attached diagram of process 20 for welding the optical shaft, the other end of the rough machining is removed to remove the blank allowance, and the machining is completed without leaving any allowance to obtain the welded optical shaft.

[0090] 3) 30 precision machining: Reusing one piece Figure 3 The forged welded optical shaft blank shown is held in a three-jaw chuck, aligned, and pressed... Figure 11The high-frequency quenched test bar is machined according to the attached diagram of the welding shaft 30 process. The two ends are turned over and connected to the machine to obtain the turbine shaft high-frequency quenched test bar (because the turbine shaft bearings must have certain wear resistance and high hardness to meet the usage requirements, the turbine shaft bearings need to be quenched, and a certain quenching depth and hardness are required. Therefore, to ensure that the machined turbine shaft meets the design requirements, a turbine shaft high-frequency quenched test bar needs to be machined. The structure of the test bar should be consistent with the journal structure of the turbine shaft, but attention should be paid to leaving a 0.3mm grinding allowance on the outer circle of each high-frequency quenched section; the high-frequency quenched test bar is used in the subsequent turbine shaft 70 heat treatment process as a high-frequency quenched sample for quenching dissection test of hardness and quenching depth).

[0091] 4) 40 clamp: The drawing number and batch number are engraved on the outer circle of the high-frequency quenched test bar at the location shown in the part drawing and on the Ф65.

[0092] S2. Welding turbine disk machining process steps: Using... Figure 5 The forged welded turbine disk blank shown is processed according to the following process: 10 rough turning → 20 rough turning → 30 finish turning → 40 finish turning → 50 clamping.

[0093] The specific process steps are as follows:

[0094] 1) 10 Roughing: Clamp the outer diameter with jaws, align, and press... Figure 12 The attached diagram shows the 10th process for welding the turbine disk. Roughly turn one end to remove the large amount of blank material, leaving a 1mm allowance on the end face and outer circle.

[0095] 2) 20 Rough Turning: Turn around, clamp the already machined outer diameter with a three-jaw chuck, bring it close to the flat end face, align the already machined outer diameter, and press... Figure 13 For the welding turbine disk, in step 20, rough turn the other end to remove the large amount of blank material, leaving a 1mm allowance on the end face and outer circle.

[0096] 3) 30mm precision turning: Clamp the outer diameter with a soft three-jaw chuck, align the outer diameter and the runout of the already machined end face on its left side to within 0.05mm, and proceed as follows. Figure 14 The attached diagram shows the precision machining of the turbine end in step 30 of the welding turbine disk process.

[0097] 4) 40mm precision turning: Clamp the outer diameter with a soft three-jaw chuck, align the already machined outer diameter and its left end face with a runout within 0.03mm, and proceed according to... Figure 15 The welded turbine disk is obtained by precision machining the pressing end in step 40 of the welding process shown in the attached diagram.

[0098] 5) 50 clamps: blunt the sharp edges of the parts, remove burrs, and engrave the part number and batch number according to the drawing requirements.

[0099] S3. Welding turbine shaft machining process steps: using pre-machined... Figure 4 Welding optical axis Figure 6The welding turbine disk is processed according to the following steps: 10 Welding → 20 Heat Treatment → 30 Machining → 40 Flaw Detection → 50 Wire EDM → 60 Machining → 70 Inspection → 80 Welding → 90 Heat Treatment.

[0100] The specific process steps are as follows:

[0101] 1) 10 Welding: a. Take out the welding turbine disk and welding optical shaft, clean their respective welding surfaces with acetone and let them dry; b. Perform the first piece friction welding according to the quality and strength requirements of the turbine shaft friction welding specification and the C2500 friction welding operation manual.

[0102] 2) Heat treatment: Heat treatment is carried out according to the turbine shaft friction welding specification. The welded turbine shaft after friction welding is subjected to stress-free annealing to eliminate the welding stress of the welded turbine shaft and avoid stress affecting the friction welding strength.

[0103] 3) 30 turning: The outer diameter of the weld seam of the first welded turbine shaft is turned to Ф71.2. Turning facilitates flaw detection.

[0104] 4) 40 flaw detection: The first welded piece shall be subjected to penetrant testing in accordance with the flaw detection specifications. No defects such as cracks are allowed in the test.

[0105] 5) 50 wire cutting: According to the requirements of the turbine shaft friction welding specification, four tensile test specimens are cut from the cross section of each welded turbine shaft. The four tensile test specimens are evenly distributed at 90° on the circumferential surface of the friction weld cross section and are located in the middle of the circumferential surface of the friction weld cross section. The specimen size is cut according to the R4 ratio of circular cross section specimens in the standard GB / T228.1-2010 Metallic Materials Tensile Testing.

[0106] 6) 60 turning: Turn the specimen to the required size according to the circular cross-section ratio specimen R4 in the standard GB / T228.1-2010 Metallic Materials Tensile Testing;

[0107] 7) 70 Inspection: Inspect the mechanical properties of the first piece of the friction welded turbine shaft according to the requirements of the turbine shaft friction welding specification, namely the strength of the friction weld point, tensile strength, yield strength and elongation. If all four test samples pass the test, the first piece of the friction welded turbine shaft is qualified and can proceed to the 80 and subsequent processes. If it fails, repeat the 10-70 process.

[0108] 8) 80 Welding: a. Take out the welding turbine disk and welding optical shaft, clean their respective welding surfaces with acetone and let them dry; b. Perform batch friction welding according to the quality and strength requirements of the turbine shaft friction welding specification and the C2500 friction welding operation manual.

[0109] 9) 90 Heat treatment: Heat treatment is carried out according to the turbine shaft friction welding specification. The welded turbine shaft after friction welding is subjected to stress-free annealing to eliminate the welding stress of the welded turbine shaft.

[0110] S4. Turbine shaft machining process steps: using pre-machined... Figure 7 The welding turbine shaft is processed according to the following steps: 10 rough turning → 20 rough turning → 30 grinding → 40 finish turning → 50 finish turning → 60 inspection → 70 heat treatment → 80 turning → 90 grinding → 100 CNC milling → 110 fitting → 120 finish turning → 130 inspection → 140 CNC milling → 150 broaching → 160 grinding → 170 finish turning → 180 fitting.

[0111] The specific process steps are as follows:

[0112] 1) 10 rough car: a. according to Figure 16 The attached diagram shows the 10th process of the turbine shaft: b) Clamp the outer diameter with a three-jaw chuck, hold the end face, align circle A and surface B, ensuring runout is no more than 0.03mm, and finish a section of the outer diameter; c) Erect the center support, machine the total length to the required dimension, and drill the center hole B4 / 12.5; d) Remove the center support after drilling the center hole, and proceed with the process. Figure 16 For turbine shaft 10, machine the remaining outer diameter and steps to the required specifications (see attached diagram).

[0113] 2) Rough turning: Turn around, clamp the outer circle with a three-jaw chuck, set up the center support, align the runout of circle A and surface B to no more than 0.05mm, and proceed as follows. Figure 17 The turbine shaft is machined according to the attached drawing for process 20, and a center hole of B4 / 12.5 is drilled.

[0114] 3) 30 grinding: Double center clamping, according to... Figure 18 The turbine shaft is rough ground according to the attached drawing for process 30, and the end face and outer circle shown in the drawing are polished to be used as the clamping and alignment reference for subsequent finish machining processes.

[0115] 4) 40 precision turning: The outer diameter of the turbine disc is chucked with a soft three-jaw chuck, the end face is flat, the center hole is at the top, and the two-stage reference circle of the 30-process machining is recalibrated, with runout not exceeding 0.02mm. Figure 19 The turbine shaft 40 process diagram shows the precision machining of the pressed end;

[0116] 5) 50mm precision turning: Turn around, use a soft three-jaw chuck to clamp the outer diameter, place the center support on the center hole, align the already turned outer diameter and ensure the runout of the turbine disc end face is no more than 0.05mm, then proceed as follows: Figure 20 The turbine shaft is precision machined at the turbine end in process 50. Note: Sufficient machining allowance was reserved during the design and machining of the turbine disk to address the issue of fixed connection during the broaching of the turbine shaft tenon groove. This lays the groundwork for the precision machining of the M85x3 external thread connecting bracket in this process. The M85x3 external thread connecting bracket is used for connection and fixation during the subsequent broaching of the tenon groove. This M85x3 external thread connecting bracket successfully solves the problem of lacking a reliable and secure connection and fixation scheme when using turbine end positioning for broaching the turbine shaft tenon groove.

[0117] 6) 60 Inspection: Conduct penetrant testing on the turbine shaft welds according to the flaw detection inspection specifications. No defects such as cracks are allowed in the test.

[0118] 7) Heat Treatment: Perform high-frequency quenching on the turbine shaft quenching locations according to the drawing requirements; Note: a) A 0.25mm allowance is left on each side of the outer diameter of the quenching journal. The quenching parameters and other settings need to consider grinding to ensure sufficient quenching hardness and depth; b) Before machining the turbine shaft, perform a trial machining using a high-frequency quenched sample piece precision-machined in step 30 of the welding shaft machining process in S1. Only after the sample piece passes inspection and meets the requirements can the turbine shaft be machined; c) Deformation must be controlled during machining. Check with two ejector pins. The runout of the outer diameter of each section of the turbine shaft should not exceed 0.06mm. max0.2X45°

[0119] 8) 80 lathe: On a conventional lathe, use carbide centers to grind the center holes at both ends of the turbine shaft to repair the center holes that were scratched or roughened during turning and inspection, thereby ensuring the reliability of the grinding and clamping reference in subsequent processes.

[0120] 9) 90-degree grinding: Double-center clamping, according to... Figure 21 The turbine shaft 90 process diagram shows the fine grinding of the outer diameter and end face of each section to the required standard. Note: a) The turbine disk has a thickness of 47.606±0.05mm, and the allowance on both sides is evenly distributed and ground; b) The sharp edges generated by grinding are removed with an oilstone, with a maximum thickness of 0.2X45mm.

[0121] 10) 100 CNC milling: use a soft three-jaw chuck to clamp the outer diameter of the turbine disk and the center hole at the top. Recheck the runout of the turbine disk end face and bearing reference P and Q to be no more than 0.015mm. Mill the triangular pyramid shape according to the drawing requirements.

[0122] 11) 110 clamps: Apply the taper protection sleeve to the triangular pyramid part after the 100-step machining process;

[0123] 12) 120 precision turning: Use a soft three-jaw chuck to clamp the outer diameter of the turbine disc, assemble a center support (supporting the reference circle P), align the bearing stops to the reference circles P and Q, ensuring the runout is no greater than 0.02mm. Figure 22 The turbine shaft 120 process diagram shows the precision machining of the turbine shaft pressure end thread and hole to the required specifications;

[0124] 13) 130 inspection: Perform penetrant testing on the turbine shaft pressure end and vortex end bearing section and thrust bearing section according to the flaw detection inspection specifications. No defects such as cracks are allowed in the test.

[0125] 14) 140 CNC Milling: Position the upper milling tool, align the outer circle Ф239.04 (0 / -0.029) with a runout not exceeding 0.02mm, then press... Figure 23The attached diagram for process 140 of the turbine shaft shows the milling of a U-shaped positioning groove to the required specifications. Note: To address the issue of rotational misalignment during turbine shaft tenon broaching due to the large diameter and thickness of the turbine disk, resulting in significant force during cutting and causing turbine shaft rotation, a process boss was designed and machined on the inner ring of the turbine disk back during welding. This boss serves as a preparatory step for milling a U-shaped positioning anti-rotation groove on the process boss in this process. The U-shaped anti-rotation groove is used in subsequent tenon broaching processes and works in conjunction with the turbine shaft tenon broaching tool to prevent rotational misalignment, successfully resolving the issue of abnormal tenon profile rotation during turbine shaft tenon broaching.

[0126] 15) 150 Broaching: Position the upper turbine shaft tenon groove using the broaching tool, and broach the tenon groove to the required size according to the drawing. Note: a. Before machining each batch of parts, a test broaching test must be performed using a turbine shaft tenon groove test piece. The tenon groove contour is checked by slide projection. Only after passing the test can the turbine shaft tenon groove of the machined parts be broached; b. When assembling and positioning the turbine shaft, the turbine shaft U-shaped positioning groove must be matched with the tooling positioning pin for limiting position.

[0127] 16) 160 Grinding: Double center clamping, grinding to remove the burrs on the end face of the wheel after broaching the tenon groove. Note: The thickness of the wheel must be guaranteed.

[0128] 17) 170 precision turning: Clamp the outer circle with a soft three-jaw chuck (with copper padding), set up a center rest, align the bearing stops P and Q, ensuring the reference circle runout is no more than 0.01mm, then proceed as follows: Figure 24 Machining of turbine shaft 170 (see attached diagram): a) Finish turning: Remove the process pads and internal threaded holes on the inner ring of the turbine disk back and the outer circle of the turbine disk journal to the required specifications; b) Polish away the quenching induction color at the quenching location shown in the diagram, taking care to protect the grinding surface.

[0129] 18) 180 clamps: a. Engraving in the position shown in the drawing according to the requirements; b. Removing all burrs and removing the tapered protective sleeve.

[0130] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for machining a turbine shaft of a high-flow-rate turbocharger, characterized in that, Includes the following steps: S1. Machining the welding optical shaft blank to obtain the welding optical shaft; S2. Machining the welded turbine disk blank to obtain the welded turbine disk; S3. The welding optical shaft and the welding turbine disk are assembled by friction welding to obtain the welded turbine shaft; S4. Machining and welding the turbine shaft to obtain the finished turbine shaft; Step S1 includes: S110 rough turning: Take the welding shaft blank, clamp the outer circle with a three-jaw chuck, align it, rough turn one end to remove the blank allowance, and process it to the position without leaving any allowance. S120 rough turning: Turn around, use the three-jaw chuck to turn the outer diameter, align, rough turn the other end to remove the blank allowance, and process to the point without leaving any allowance to obtain the weldable optical shaft; Step S2 includes: S210 rough turning: Take the welded turbine disk blank, clamp the outer circle with a three-jaw chuck, align it, rough turn one end to remove the large allowance of the blank, and leave a 1mm allowance on the end face and the outer circle. S220 rough turning: Turn around, use the three-jaw chuck to machine the outer diameter, bring it to the flat end face, align the machined outer diameter, rough turn the other end to remove the large amount of blank material, leave 1mm allowance on the end face and outer diameter respectively. S230 precision machining: use a soft three-jaw chuck to clamp the outer diameter, align the outer diameter and the runout of the machined end face to within 0.05mm, and precision machine the scroll end; S240 precision machining: Clamp the outer diameter with a soft three-jaw chuck, align the machined outer diameter and the runout of the machined end face to within 0.03mm, and precision machine the pressing end to obtain the welded turbine disk; Step S3 includes: S310 welding: a. Take the welding turbine disk and welding optical shaft, clean and dry their respective welding surfaces; b. Perform friction welding on the first piece; S320 heat treatment: Stress-free annealing is performed on the welded turbine shaft after friction welding to eliminate the welding stress on the welded turbine shaft and avoid stress affecting the strength of friction welding. S330 machine: The outer circle of the turbine shaft weld is welded for the first piece of machining and welding, which facilitates weld flaw detection; S340 flaw detection: Penetrant testing is performed on the first welded piece, and cracks and defects are not allowed to be detected. S350 wire cutting: Four tensile test specimens were cut from the cross section of each welded turbine shaft. The four tensile test specimens were evenly distributed at 90° on the cross-sectional circumference of the friction weld point and were located at the middle of the cross-sectional circumference of the friction weld point. S360 lathe: Turn the sample dimensions to the required size; S370 inspection: Inspect the strength of the friction weld point of the first piece welded, including tensile strength, yield strength, and elongation; If all four tensile test specimens pass the test, repeat steps S310-S320 for mass production; if they fail, repeat steps S310-S370. Step S4 includes: S410 rough turning: a. Take the finished welded turbine shaft, clamp the outer diameter with a three-jaw chuck, hold the end face, align the outer diameter and end face of the turbine disk, ensuring the runout is no more than 0.03mm, and finish the outer diameter of the turbine shaft pressure end section; b. Set up a center frame, turn the total length to the required dimensions, and drill the center hole for the turbine shaft pressure end; c. Remove the center hole, remove the center frame, and turn the outer diameters and steps of each section of the turbine shaft pressure end to the required dimensions. S420 rough turning: turn around, use a three-jaw chuck to check the outer diameter, set up a center rest, align the outer diameter of the turbine disk, ensure the end face runout is no more than 0.05mm, machine the outer diameter of the turbine disk and the end face of the turbine end, and drill the center hole of the turbine shaft end. S430 grinder: Double center clamping, rough grinding the outer diameter of the turbine disk, the end face of the turbine end, and the two reference circles of the turbine shaft pressure end, which are used for clamping and alignment references in subsequent fine turning processes. S440 precision machining: soft three-jaw chuck turbine disk outer circle, end face close to flat, top center hole, recalibrate S430 process two gear reference circle ground, runout no more than 0.02mm, precision machining pressing end; S450 precision machining: Turn around, use a soft three-jaw clamp to clamp the outer diameter, attach the center support to the center hole, align the already machined outer diameter and ensure the runout of the turbine disk end face is no more than 0.05mm, and precision machine the turbine end; S460 inspection: Penetrant testing is performed on the turbine shaft welds, and no cracks or defects are allowed. S470 heat treatment: High-frequency quenching is performed on the quenching location of the turbine shaft; S480 lathe: On the lathe, use carbide tips to grind the center holes at both ends of the turbine shaft to repair the center holes that were scratched or roughened during turning and inspection, thereby ensuring the reliability of the grinding and clamping reference in subsequent processes. S490 grinder: Double center clamping, for precision grinding of the outer diameter and end face of each grade to the required standard; S4100 CNC milling: Use a soft three-jaw chuck to clamp the outer diameter of the turbine disk, top center hole, recalibrate the turbine disk end face and bearing stop reference runout to be no more than 0.015mm, and mill the triangular pyramid to the required size; S4110 clamps: Fit the tapered protective sleeve onto the triangular pyramidal part after the S4100 process; S4120 precision machining: Clamp the outer diameter of the turbine disc with a soft three-jaw chuck, set up a center support, align the bearing stop reference outer diameter, and ensure the runout is no more than 0.02mm. Precision machine the end thread and hole of the turbine shaft pressure end to the requirements. S4130 Inspection: Penetrant testing is performed on the turbine shaft pressure end, turbine end bearing, and thrust bearing. Cracks and defects are not allowed to be detected. S4140 CNC milling: After aligning the outer circle runout of the turbine disk step to no more than 0.02mm, mill the U-shaped positioning groove to the required size; S4150 broaching: Broach the tenon to the required size; S4160 grinder: Double center clamping, grinding to remove burrs from the end face of the wheel disc after broaching the tenon groove; S4170 precision machining: Clamp the outer circle with a soft three-jaw chuck, set up a center support, align the bearing stop reference circle with a runout of no more than 0.01mm, then precision machine, and polish away the quenching induction color at the quenching position. S4180 pliers: Deburr and remove the tapered protective sleeve.

2. The machining method for a high-flow-rate turbocharger turbine shaft according to claim 1, characterized in that, In the S450 process, the outer diameter of the turbine disk journal is precision machined with external threads. The external threaded parts are used for subsequent tenon and groove broaching for connection and fixation. A process boss is provided on the inner ring of the turbine disk back. In process S4140, a U-shaped positioning anti-rotation groove is milled on the process boss. The U-shaped anti-rotation groove is used in the subsequent process of tenon and slot broaching, and is used to prevent rotation and limit the rotation in conjunction with the turbine shaft tenon and slot broaching tool. In the S4170 process, the process mounts, process bosses, and internal threaded holes are machined to the required specifications by turning.

3. The machining method for a high-flow-rate turbocharger turbine shaft according to claim 1, characterized in that, Step S1 includes S130 precision machining: Take a new welded optical shaft blank, clamp it with a three-jaw chuck, align it, machine a high-frequency quenched test bar, turn the two ends over and machine it to obtain a high-frequency quenched test bar for the turbine shaft. The structure of the test bar is required to be consistent with the journal structure of the turbine shaft. In the S470 process, a test bar is first used for trial processing. After the test is qualified and meets the requirements, the turbine shaft quenching position is then subjected to high-frequency quenching.

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