Large POD propeller rotor shaft dovetail groove rotation positioning processing tool and processing method

Abstract

The application discloses a machining tool and method for positioning and machining dovetail grooves of a large POD propeller rotor shaft. The tool comprises a first and a second rotary bracket, a hydraulic pressure assembly, a mechanical indexing positioning assembly and an angle encoder detection assembly, which are arranged along the rotor shaft in an axial direction. During machining, two rotary reference outer circles are formed on the rotor shaft and supported on the two rotary brackets, and then the theoretical angle of one end is determined by a dividing disc and a positioning pin, and the actual angle of the other end is detected by an angle encoder. After the angle error meets the requirements, the dovetail grooves are pressed and milled. The scheme can reduce the cumulative error between grooves of a long shaft, and improve the circumferential distribution accuracy and the consistency of the pressing.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion core shaft system manufacturing technology, and in particular to a machining tooling and method for rotary positioning machining of dovetail grooves on large POD propulsion rotor shafts, which is applicable to the precision machining of multiple grooves on the outer diameter of large long shaft parts such as large podded propulsion units, motor rotor shafts, and marine propulsion shaft systems. Background Technology

[0002] A podded propulsion (POD) system, also known as a nacelle propulsion system or azimuth thruster, integrates the propulsion motor, propeller, and related transmission structures into a pod structure. This reduces the need for traditional shafting, rudder systems, and some transmission mechanisms, making the ship's propulsion system more compact. For the core shafting of a POD propulsion system, the rotor shaft typically serves multiple functions, including connecting the motor rotor and propeller shaft, and mounting braking components. Its machining accuracy directly affects the stability, safety, and reliability of the propulsion system.

[0003] Large POD (Potentially Occurring Device) propeller rotor shafts are typically characterized by their long length, large diameter, heavy weight, high requirements for outer diameter precision, and numerous slots. For example, some POD propeller rotor shafts can reach lengths of over 7500 mm, maximum outer diameters of over 1500 mm, and weights of over 20 tons. Multiple dovetail grooves evenly distributed along the circumference need to be machined on their outer diameter, requiring high precision in groove width, spacing, and surface roughness. During the machining of these large shaft parts, angular errors during each workpiece rotation, torsional errors at both ends of the long shaft, support clearance errors, clamping deformation, and repeated clamping errors all affect the final positional accuracy of the dovetail grooves.

[0004] Existing publicly available literature contains technical solutions for rotary indexing devices. For example, CN110125774B discloses a direct-drive high-precision rotary indexing device, which mainly improves the indexing accuracy of machine tools through a high-precision rotary mechanism. While this type of technology can improve the indexing performance of general-purpose rotary equipment, it typically targets machine tool rotary tables or general-purpose rotary indexing mechanisms, and does not offer specific solutions for double-end angle error verification and long-axis cumulative error control in the machining of large, long, and heavy POD rotor shafts with multiple long dovetail grooves on their outer diameter.

[0005] Existing publicly available literature also contains technical solutions for the welding and manufacturing of large or hollow spindles. For example, CN102430893A discloses a method for manufacturing a small-diameter hollow spindle, which completes the manufacturing of the hollow spindle through segmented forging, welding, stress-relief annealing, and finishing, and involves assembly stops and weld beveling. This type of technology mainly solves the problems of segmented manufacturing and welding quality of hollow spindles, but it cannot directly solve the problem of rotational positioning accuracy when machining the outer diameter of a large POD rotor shaft with multiple grooves.

[0006] Furthermore, CN203124800U discloses a combined U-drill bit and its method for drilling stepped holes, which can improve the efficiency of stepped hole machining; CN114850781B discloses an assembly method for the drum and drum shaft of a large ship lift, involving the heating, cooling, and alignment control during the assembly process of large components. The above technologies involve stepped hole machining and large component assembly, respectively, but do not provide a collaborative control scheme of "support datum, mechanical indexing, encoder verification, and hydraulic clamping" for the machining of dovetail grooves on the large rotor shaft of a POD propeller.

[0007] Therefore, existing technologies still have the following shortcomings: First, large, long-shaft workpieces are heavy and long, making it difficult to effectively identify and control the angle difference between the two ends of the workpiece when using single-end indexing or ordinary bracket support; second, during the indexing process of multiple dovetail grooves, if the rotation error is not checked in time, it is easy to generate cumulative errors in the distance between the grooves; third, when the workpiece is repeatedly rotated and clamped, manual clamping is labor-intensive and results in poor clamping consistency; fourth, existing general-purpose rotary indexing mechanisms are difficult to directly adapt to the machining scenario of long dovetail grooves on the outer circle of large rotor shafts of POD propellers. Based on this, it is necessary to propose a special rotary positioning machining fixture and machining method suitable for machining dovetail grooves on large POD propeller rotor shafts. Summary of the Invention

[0008] Design Purpose: The purpose of this invention is to provide a machining fixture and method for rotary positioning of dovetail grooves on a large POD propeller rotor shaft, in order to solve the problems of difficult rotary positioning, difficulty in controlling the angle error at both ends, easy accumulation of error in the distance between grooves, and high labor intensity of repeated clamping in the machining of multiple dovetail grooves on the outer circle of a large POD propeller rotor shaft.

[0009] Design Scheme: To achieve the above design objectives, the design mechanism adopted by this invention is as follows: This invention addresses the characteristics of large POD propeller rotor shaft 1, such as long length, large diameter, heavy weight, numerous dovetail grooves on the outer circle, and high circumferential distribution accuracy requirements. It employs a combined machining control approach of "two rotational reference supports, one end mechanical indexing positioning, the other end angle encoding verification, and hydraulic clamping fixation" to achieve angular positioning accuracy control and machining stability control of large long shaft workpieces during multiple rotational milling processes.

[0010] Specifically, a first and a second rotational reference outer circle are first formed on the rotor shaft by grinding. The first rotational reference outer circle is supported on a first rotation bracket, and the second rotational reference outer circle is supported on a second rotation bracket. Since the two rotational reference outer circles are grinding reference surfaces, their roundness, coaxiality, and surface quality are high, which can provide a stable and reliable support reference for the subsequent multiple rotations of the rotor shaft, reducing rotational runout and positioning deviations caused by ordinary blank outer circles or non-reference surface supports.

[0011] A mechanical indexing and positioning assembly is installed at one end of the rotor shaft. The indexing plate in the mechanical indexing and positioning assembly is coaxially connected to the end of the rotor shaft. Multiple indexing and positioning holes on the indexing plate are evenly distributed circumferentially at predetermined angles. When the rotor shaft needs to rotate to the next machining angle, the mechanical indexing and positioning of one end of the rotor shaft is achieved by the engagement of a positioning pin with the corresponding indexing and positioning hole. For machining 20 dovetail grooves, the central angle between adjacent indexing and positioning holes is 18°, so that each rotation angle is consistent with the circumferential distribution angle of the dovetail grooves.

[0012] Simultaneously, an angle encoding detection component is installed at the other end of the rotor shaft. The connecting disc in the angle encoding detection component is coaxially connected to the other end of the rotor shaft. The angle encoder is mounted via an encoder base and detects the actual rotation angle at that end. An angle display or angle comparison unit is used to display or compare the detected angle. Because large rotor shafts have long axial dimensions and heavy weight, problems such as inconsistencies in angles at both ends, shaft torsion, support clearance effects, and human error may exist during rotation. Therefore, this invention does not rely solely on indexing and positioning at one end. Instead, while determining the theoretical rotation angle at one end using an indexing disc and positioning pin, the actual rotation angle is detected by the angle encoder at the other end, and the theoretical angle is compared with the actual angle.

[0013] Once the error between the theoretical rotation angle corresponding to the mechanical indexing and positioning component and the actual rotation angle detected by the angle encoding and detection component meets the preset error requirement, the hydraulic cylinder in the hydraulic clamping component drives the pressure plate to clamp the rotor shaft, keeping the rotor shaft stable and fixed during the dovetail groove milling process, thus preventing the workpiece from rotating, shifting, or vibrating due to the machining cutting force. When it is time to proceed to the next dovetail groove, the hydraulic cylinder drives the pressure plate to release the rotor shaft, and then the next rotation indexing and angle verification is performed.

[0014] Therefore, this invention forms a closed-loop processing flow of "releasing clamping—mechanical indexing—coding verification—error judgment—hydraulic clamping—dovetail groove machining". This flow can promptly confirm whether the angles at both ends of the rotor shaft 1 are consistent before each dovetail groove machining, avoiding the cumulative error in the groove distance caused by the failure to detect single errors during multiple rotations; at the same time, the hydraulic clamping component can improve clamping consistency, reduce the labor intensity of repeated manual clamping, and reduce the impact of human operation differences on machining accuracy.

[0015] Therefore, through the coordinated operation of the first rotary bracket, the second rotary bracket, the hydraulic clamping assembly, the mechanical indexing and positioning assembly, and the angle coding detection assembly, this invention can improve the groove width accuracy, groove distance accuracy, and circumferential distribution accuracy of the dovetail groove on the outer circle of the rotor shaft of a large POD propeller. It is particularly suitable for the precision machining of core shaft components of large POD propellers with a length of not less than 7000 mm, a maximum outer diameter of not less than 1500 mm, and a weight of not less than 20 t.

[0016] Technical Solution 1: A rotary positioning machining fixture for the dovetail groove of a large POD propeller rotor shaft, comprising a first rotary bracket, a second rotary bracket, a hydraulic clamping assembly, a mechanical indexing positioning assembly, and an angle coding detection assembly.

[0017] The first and second rotary supports are spaced apart along the axial direction of the rotor shaft, and are used to support the first and second rotary reference outer circles on the rotor shaft, respectively. The first and second rotary reference outer circles are preferably outer circle reference surfaces formed by grinding, so as to ensure the rotational stability and reference reliability of the rotor shaft on the two rotary supports.

[0018] The hydraulic clamping assembly is located on or near the first and second rotary supports, and includes a pressure plate and a hydraulic cylinder. The hydraulic cylinder is used to drive the pressure plate to clamp or release the rotor shaft; during dovetail groove milling, the hydraulic clamping assembly restricts the rotor shaft from rotating, moving, or vibrating; when the rotor shaft needs to rotate, the hydraulic clamping assembly releases the rotor shaft.

[0019] The mechanical indexing and positioning assembly is located at one end of the rotor shaft and includes an indexing plate, indexing positioning holes, positioning pins, end connectors, fasteners, and end positioning holes. The indexing plate is coaxially connected to the end of the rotor shaft via the end connectors and is fixed by fasteners; the end positioning holes are used to achieve the positioning connection between the indexing plate and the end of the rotor shaft. The indexing plate has multiple indexing positioning holes evenly distributed along the circumferential direction. After the positioning pin is inserted into the corresponding indexing positioning hole, the current theoretical rotation angle of the rotor shaft is determined.

[0020] An angle encoding detection component is located at the other end of the rotor shaft and includes an angle encoder, an encoder base, a connecting plate, and an angle display or angle comparison unit. The connecting plate is coaxially connected to the other end of the rotor shaft. The angle encoder is used to detect the actual rotation angle at the other end of the rotor shaft, and the angle display or angle comparison unit is used to display the actual angle or compare the actual angle with the theoretical angle.

[0021] Technical Solution 2: A method for machining dovetail grooves for a large POD propeller rotor shaft, comprising: machining two rotational reference outer circles on the rotor shaft; hoisting the rotor shaft onto two rotational brackets; installing a mechanical indexing positioning assembly at one end of the rotor shaft and an angle coding detection assembly at the other end; performing initial angle correction; releasing the hydraulic clamping assembly and rotating the rotor shaft at a predetermined angle; performing end mechanical positioning using the mechanical indexing positioning assembly and detecting the actual angle at the other end using the angle coding detection assembly; determining whether the error between the theoretical rotation angle and the actual rotation angle meets the preset error requirement; if the error meets the requirement, clamping the rotor shaft and performing dovetail groove milling; if the error does not meet the requirement, readjusting the positioning; repeating the above steps until all dovetail grooves are machined.

[0022] Compared with the prior art, this invention has the following advantages: First, it adopts a dual-end angle control method of "mechanical indexing and positioning component + angle encoding and detection component". One end performs mechanical indexing and positioning, while the other end performs actual angle detection, which can effectively detect the angle deviation between the two ends of a large long shaft and reduce the cumulative error in the long shaft rotation machining. Second, this invention uses the first and second rotation reference outer circles as the support references for the bracket, which can improve the support stability and reference consistency of the large rotor shaft during the rotation machining process. Third, this invention uses a hydraulic clamping component to achieve clamping and loosening, reducing manual repetitive clamping operations, improving clamping consistency, and reducing labor intensity. Fourth, this invention is suitable for machining large POD propeller rotor shafts with multiple dovetail grooves evenly distributed on the outer circle, which can improve the accuracy of dovetail groove width, groove distance, and circumferential distribution. Fifth, the tooling structure of this invention is relatively simple, and can be based on a steel plate welded bracket, indexing plate, positioning pin, connecting plate, and angle encoder, with low manufacturing cost, suitable for single-piece or small-batch precision machining of large shaft parts. Attached Figure Description

[0023] Figure 1 This is an overall tooling structure diagram of the dovetail groove rotary positioning machining tooling for the large POD propeller rotor shaft of the present invention.

[0024] Figure 2 This is a schematic diagram of the dual-end control of the indexing plate and the angle encoder of the present invention.

[0025] Figure 3 This is a structural diagram of the rotary bracket and hydraulic clamping assembly of the present invention.

[0026] Figure 4 This is a structural diagram of the mechanical indexing and positioning component of the present invention.

[0027] Figure 5 This is a structural diagram of the angle encoding detection component of the present invention.

[0028] Figure 6 This is a flowchart of the dovetail groove rotary positioning machining method of the present invention.

[0029] Figure 7 This is a schematic diagram of the step-by-step processing of the dovetail groove of the present invention.

[0030] Explanation of reference numerals in the attached drawings: 1. Rotor shaft; 11. Outer circle of the first rotation reference; 12. Outer circle of the second rotation reference; 13. Dovetail groove; 2. First rotation bracket; 3. Second rotation bracket; 4. Hydraulic clamping assembly; 41. Pressure plate; 42. Hydraulic cylinder; 5. Mechanical indexing and positioning assembly; 51. Indexing plate; 52. Indexing and positioning hole; 53. Positioning pin; 54. End connector; 55. Fastener; 56. End positioning hole; 6. Angle encoding detection assembly; 61. Angle encoder; 62. Encoder base; 63. Connecting plate; 64. Angle display or angle comparison unit; 7. Worktable; 71. Rapid feed milling cutter; 72. Roughing milling cutter; 73. Forming cutter. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0032] Example 1: A rotary positioning machining fixture for dovetail grooves of a large POD propeller rotor shaft, suitable for a large POD propeller rotor shaft 1 with a length of approximately 7504 mm, a maximum outer diameter of approximately φ1590.6 mm, and a weight of approximately 26.4 t. Twenty dovetail grooves 13, evenly distributed along the circumference, need to be machined on the outer circumference of the rotor shaft 1. Each dovetail groove 13 has a length of approximately 2785 mm, a groove width of 45.251 ± 0.05 mm, and a distance of 199.364 ± 0.05 mm between adjacent dovetail grooves.

[0033] The machining fixture includes a first rotary support 2, a second rotary support 3, a hydraulic clamping assembly 4, a mechanical indexing and positioning assembly 5, and an angle encoding detection assembly 6. The first rotary support 2 and the second rotary support 3 are arranged axially at intervals along the rotor shaft 1. Before machining, two suitable support positions are selected on the rotor shaft 1, and the first rotary reference outer circle 11 and the second rotary reference outer circle 12 are formed by external cylindrical grinding. In this embodiment, the first rotary reference outer circle 11 can be a φ555 position, and the second rotary reference outer circle 12 can be a φ661 position; the two rotary supports are respectively matched with the corresponding rotary reference outer circles, and the fit clearance is preferably 0.5mm.

[0034] The first rotary support 2 and the second rotary support 3 can be made of welded steel plates and fixed to the worktable 7. Preferably, the main body of the support is formed by welding steel plates with a thickness of 50mm to meet the rigidity requirements of the large rotor shaft support. The upper part of the support extends above or to the side above the rotor shaft 1 and is equipped with a hydraulic clamping assembly 4.

[0035] The hydraulic clamping assembly 4 includes a pressure plate 41 and a hydraulic cylinder 42. The hydraulic cylinder 42 is mounted on the first rotary support 2 or the second rotary support 3, or located near the rotary support. The pressure plate 41 is connected to the hydraulic cylinder 42. When the rotor shaft 1 rotates, the hydraulic cylinder 42 retracts, causing the pressure plate 41 to release the rotor shaft 1. When the rotor shaft 1 rotates to its correct position and the angle verification is qualified, the hydraulic cylinder 42 drives the pressure plate 41 to clamp the rotor shaft 1, ensuring that the rotor shaft 1 does not move during the milling of the dovetail groove 13.

[0036] A mechanical indexing and positioning assembly 5 is disposed at one end of the rotor shaft 1. The mechanical indexing and positioning assembly 5 includes an indexing plate 51, indexing positioning holes 52, positioning pins 53, an end connector 54, fasteners 55, and an end positioning hole 56. The end connector 54 is connected to the end of the rotor shaft 1. The indexing plate 51 is coaxially fixed to the rotor shaft 1 via the end connector 54 and is positioned and connected to the end of the rotor shaft 1 via the end positioning hole 56. Twenty indexing positioning holes 52 are evenly distributed along the circumferential direction on the indexing plate 51, with a central angle of 18° between adjacent indexing positioning holes 52. The positioning pins 53 are preferably two standard pins, each inserted into a corresponding indexing positioning hole 52, to improve the reliability of the mechanical indexing and positioning.

[0037] An angle encoding detection component 6 is located at the other end of the rotor shaft 1. The angle encoding detection component 6 includes an angle encoder 61, an encoder base 62, a connecting plate 63, and an angle display or angle comparison unit 64. The connecting plate 63 is coaxially connected to the end of the rotor shaft 1. The angle encoder 61 is mounted on the encoder base 62 and is connected to the connecting plate 63 for transmission or detection, used to obtain the actual rotation angle of the other end of the rotor shaft 1. The angle display or angle comparison unit 64 is used to display the angle value detected by the angle encoder 61, or to compare it with the theoretical graduation angle corresponding to the mechanical indexing and positioning component 5.

[0038] With the above structure, after each rotation of the rotor shaft 1, it can be mechanically positioned by the indexing plate 51 and positioning pin 53 at one end, and the angle can be checked by the angle encoder 61 at the other end, thereby determining whether there is an angle deviation at both ends of the large long shaft. When the angle error at both ends meets the preset requirements, the dovetail groove 13 is then machined.

[0039] Example 2: A method for machining the dovetail groove of a large POD propeller rotor shaft by rotation positioning, using the machining fixture described in Example 1, including the following steps: The first step is to determine the rotation datum. Based on the overall shape of the rotor shaft 1, the machining range of the dovetail groove 13, and the existing machining equipment conditions, two support positions are selected on the rotor shaft 1, and the first rotation datum outer circle 11 and the second rotation datum outer circle 12 are formed by external cylindrical grinding. The two outer cylindrical datum surfaces serve as the support datum for subsequent rotational machining.

[0040] The second step is to clamp the rotor shaft. The first rotary bracket 2 and the second rotary bracket 3 are fixed on the worktable 7 of a floor-type milling machine or other suitable large machining equipment, and the axial positions of the first rotary bracket 2 and the second rotary bracket 3 correspond to the first rotary reference outer circle 11 and the second rotary reference outer circle 12, respectively. The rotor shaft 1 is then hoisted onto the two rotary brackets using a crane, with the first rotary reference outer circle 11 supported on the first rotary bracket 2 and the second rotary reference outer circle 12 supported on the second rotary bracket 3.

[0041] The third step is to install the dual-end angle control assembly. Install the mechanical indexing and positioning assembly 5 at one end of the rotor shaft 1 to fix the indexing plate 51 coaxially with the rotor shaft 1; install the angle encoding and detection assembly 6 at the other end of the rotor shaft 1 to connect the connecting plate 63 coaxially with the rotor shaft 1 and enable the angle encoder 61 to detect the actual angle at the other end of the rotor shaft 1.

[0042] Step 4, initial calibration. Adjust the initial angle of rotor shaft 1 so that indexing plate 51 is in the initial indexing position, and at the same time, zero the angle encoder 61 or record the initial angle value. After calibration, clamp rotor shaft 1 with hydraulic clamping assembly 4 and machine the first dovetail groove 13.

[0043] Step 5, indexing. After completing the machining of one dovetail groove, loosen the hydraulic clamping assembly 4, pull out the positioning pin 53, rotate the rotor shaft 1 by 18°, so that the positioning pin 53 is inserted into the next set of indexing positioning holes 52, thereby completing the mechanical indexing positioning.

[0044] Step 6, Angle Verification. After mechanical indexing and positioning, the actual rotation angle of the other end of rotor shaft 1 is detected by angle encoder 61. The actual rotation angle is compared with the theoretical rotation angle corresponding to mechanical indexing and positioning component 5. When the circumferential position error of the angle error at both ends, converted to the outer circle where the dovetail groove is located, is not greater than 0.05mm, or the angle error calculated by angle encoder 61 is not greater than the preset angle error, the rotation positioning is judged to be qualified; when the error is unqualified, the rotation position of rotor shaft 1 is readjusted and verified again.

[0045] Step 7, clamping. After the rotation positioning is qualified, the pressure plate 41 is driven by the hydraulic cylinder 42 to clamp the rotor shaft 1, and then the milling of the next dovetail groove 13 is carried out. The dovetail groove 13 can be machined by using a fast feed milling cutter 71 for roughing, a rough milling cutter 72 for semi-finishing, and a forming cutter 73 for forming.

[0046] Step 8, repeat the machining process. Repeat steps 5 to 7 until all 20 dovetail grooves 13 are machined. Using the above machining method, mechanical indexing and positioning are performed at one end and encoder verification is performed at the other end before each machining of the dovetail groove 13. This avoids the problem of inconsistent angles at both ends of a large long shaft caused by relying solely on single-end indexing, which helps to ensure the accuracy of the width, spacing, and circumferential distribution of the dovetail groove 13.

[0047] Example 3 (Step-by-Step Machining of Dovetail Groove): Based on Examples 1 and 2, this example further illustrates the tool combination for machining dovetail grooves. The following tool combination can be used to machine the dovetail groove 13 on the outer circle of the rotor shaft 1 of a large POD propeller.

[0048] First, a fast-feed milling cutter 71 is used to rough-machine the dovetail groove 13 to quickly remove most of the excess material. Second, a roughing milling cutter 72 is used to semi-finish the dovetail groove 13 to correct the excess material at the bottom and sides of the groove. Finally, a forming cutter 73 is used to shape the dovetail groove 13 so that the groove width, groove angle and surface roughness of the dovetail groove 13 meet the design requirements.

[0049] Using the above-mentioned tool combination can reduce the machining time of a single dovetail groove 13 and improve the consistency of dovetail groove forming. For machining 20 evenly distributed dovetail grooves, the combination of double-end angle positioning and verification tooling can further reduce the cumulative error of groove distance caused by multiple rotations.

[0050] Example 4 (Coordination with other processes): The rotor shaft 1 of a large POD propeller typically also includes processes such as welding, stepped hole machining, propeller shaft interference fit, and brake component installation. These processes can be set before or after the dovetail groove 13 machining according to the actual production cycle. For example, the rotor shaft 1 can first complete the welding and stress relief treatment of the short shaft and iron core, then complete the rough machining of the outer diameter and the grinding of the first rotary reference outer diameter 11 and the second rotary reference outer diameter 12, and then use the rotary positioning machining fixture of this invention to machine the dovetail groove 13.

[0051] For the stepped hole on the outer circle of the rotor shaft 1, it can be machined after the dovetail groove 13 is machined or separately according to the process reference. For the large-diameter interference fit between the propeller shaft and the iron core, safe assembly can be achieved by controlling the heating temperature, the expansion amount of the stop, the pin hole positioning, and the bolt tightening torque. Although the above processes can be used in conjunction with the present invention, the core of the present invention lies in achieving rotary positioning accuracy control in the machining of the dovetail groove 13 of the large rotor shaft 1 through the support of the first rotary bracket 2 and the second rotary bracket 3, the clamping of the hydraulic clamping assembly 4, the indexing of the mechanical indexing and positioning assembly 5, and the verification of the angle encoding detection assembly 6.

[0052] It should be understood that although the above embodiments describe the design concept of the present invention in detail, they are only used to illustrate the present invention and do not constitute a limitation on the scope of protection of the present invention. Any equivalent substitutions, combinations, additions, or modifications made by those skilled in the art to the tooling structure, number of indexing holes, clamping method, encoder mounting method, or processing parameters without departing from the design concept of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A machining fixture for rotating and positioning the dovetail groove of a large POD propeller rotor shaft, characterized in that, include: A first rotary support and a second rotary support are spaced apart along the axial direction of the rotor shaft to be processed, respectively supporting the first and second rotary reference outer circles on the rotor shaft, and enabling the rotor shaft to rotate around its own axis at a predetermined angle; a hydraulic clamping assembly is disposed on at least one of the rotary supports or near the rotary supports, for clamping and fixing the rotor shaft after the rotor shaft has completed rotation positioning and angle verification; a mechanical indexing and positioning assembly is disposed at one end of the rotor shaft, the mechanical indexing and positioning assembly including an indexing plate coaxially connected to the end of the rotor shaft, the indexing plate having multiple indexes arranged at predetermined angular intervals. A positioning hole, the indexing positioning hole being used to cooperate with a positioning pin to determine the theoretical rotation angle of one end of the rotor shaft; an angle encoding detection component, disposed at the other end of the rotor shaft, the angle encoding detection component including an angle encoder, an encoder base and a connecting plate, the connecting plate being coaxially connected to the other end of the rotor shaft, the angle encoder being used to detect the actual rotation angle of the other end of the rotor shaft; wherein, the mechanical indexing positioning component and the angle encoding detection component are respectively located at both ends of the rotor shaft, used to perform mechanical indexing positioning at one end and angle encoding verification at the other end after each rotation of the rotor shaft, and to allow the hydraulic clamping component to clamp the rotor shaft after the angle error at both ends meets the preset error requirement.

2. The dovetail groove rotary positioning machining fixture for the large POD propeller rotor shaft according to claim 1, characterized in that: Both the first and second slewing reference outer circles are outer circle reference surfaces formed by grinding on the rotor shaft. The first and second slewing brackets respectively form slewing support fits with the corresponding outer circle reference surfaces.

3. The dovetail groove rotary positioning machining fixture for the large POD propeller rotor shaft according to claim 2, characterized in that: The first rotary bracket and the second rotary bracket are respectively provided with arc-shaped support parts adapted to the corresponding outer circular reference surface, and the fitting clearance between the arc-shaped support parts and the corresponding outer circular reference surface is 0.1mm to 1.0mm.

4. The dovetail groove rotary positioning machining fixture for the large POD propeller rotor shaft according to claim 1, characterized in that: The hydraulic clamping assembly includes a pressure plate and a hydraulic cylinder. The pressure plate is positioned above or to the side of the rotor shaft, and the hydraulic cylinder is used to drive the pressure plate to switch between a clamping position and a loosening position. The mechanical indexing and positioning assembly also includes an end connector, fasteners, and end positioning holes. The indexing plate is coaxially connected to the end of the rotor shaft through the end connector, positioned to the end of the rotor shaft through at least two end positioning holes, and fixed by the fasteners.

5. The dovetail groove rotary positioning machining fixture for the large POD propeller rotor shaft according to claim 1, characterized in that: The indexing plate has 20 indexing and positioning holes evenly distributed along the circumference, with a central angle of 18° between two adjacent indexing and positioning holes, which are used to process 20 dovetail grooves evenly distributed along the circumference. The angle encoding and detection component also includes an angle display or angle comparison unit, which is used to display the actual rotation angle detected by the angle encoder, or to compare the actual rotation angle with the theoretical rotation angle corresponding to the mechanical indexing and positioning component and output angle error information.

6. A method for machining the dovetail groove of a large POD propeller rotor shaft using rotary positioning, characterized in that, The dovetail groove rotary positioning machining fixture for a large POD propeller rotor shaft according to any one of claims 1 to 7 includes the following steps: S1, machining a first rotary reference outer circle and a second rotary reference outer circle on the rotor shaft to be machined; S2, hoisting the rotor shaft onto a first rotary bracket and a second rotary bracket, so that the first rotary reference outer circle is supported on the first rotary bracket and the second rotary reference outer circle is supported on the second rotary bracket; S3, installing a mechanical indexing positioning component at one end of the rotor shaft and an angle encoding detection component at the other end of the rotor shaft; S4, performing initial angle correction, so that the mechanical indexing positioning component is in the initial indexing position and the angle encoding detection component is... S5. Zero or record the initial angle value of the component; S6. Release the hydraulic clamping component, rotate the rotor shaft at a predetermined angle, perform end mechanical positioning through the mechanical indexing positioning component, and detect the actual rotation angle of the other end of the rotor shaft through the angle encoding detection component; S7. Determine whether the error between the theoretical rotation angle corresponding to the mechanical indexing positioning component and the actual rotation angle detected by the angle encoding detection component meets the preset error requirement; S8. When the error meets the preset error requirement, clamp the rotor shaft through the hydraulic clamping component and perform dovetail groove milling on the outer circle of the rotor shaft; S9. Repeat steps S5 to S7 until all dovetail grooves on the outer circle of the rotor shaft are machined.

7. The method for machining the dovetail groove of a large POD propeller rotor shaft by rotational positioning according to claim 6, characterized in that: In step S1, the first rotary reference outer circle and the second rotary reference outer circle are formed by grinding and are respectively located at two different positions on the axial direction of the rotor shaft.

8. The method for machining the dovetail groove of a large POD propeller rotor shaft by rotational positioning according to claim 6, characterized in that: In step S6, when the error does not meet the preset error requirement, the hydraulic clamping assembly is loosened or kept loosened, the rotation position of the rotor shaft is adjusted, and the mechanical positioning and angle coding verification are re-executed until the error meets the preset error requirement.

9. The method for machining the dovetail groove of a large POD propeller rotor shaft by rotational positioning according to claim 6, characterized in that: Twenty dovetail grooves are machined on the outer circle of the rotor shaft, evenly distributed along the circumference, with each rotation angle being 18°. The preset error requirement is that the difference between the theoretical rotation angle and the actual rotation angle, converted to the circumferential position error at the outer circle where the dovetail groove is located, is not greater than 0.05mm, or the angle error calculated by the angle encoding detection component is not greater than the corresponding preset angle error.

10. The method for machining the dovetail groove of a large POD propeller rotor shaft by rotational positioning according to claim 6, characterized in that, In step S7, each dovetail groove is sequentially roughed using a fast feed milling cutter, semi-finished using a roughing milling cutter, and formed using a forming milling cutter; the rotor shaft is a large rotor shaft in the core shaft system of the POD propeller, the length of the rotor shaft is not less than 7000mm, the maximum outer diameter is not less than 1500mm, and the weight is not less than 20t.

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