A segmented machining method for a large four-lobe shell workpiece

Abstract

The present invention discloses a segmented machining method for a large four-lobe shell workpiece, which includes rough milling the horizontal middle planes of four sub-shells respectively and milling the reference plane; fixing the two sub-shells on the same side of the vertical middle plane in a circular manner and finishing the vertical middle plane and the vertical end face; assembling and fixing the two sub-shells on the same side of the horizontal middle plane and finishing the horizontal middle plane, the bearing seat, the vertical end face and the reference inner hole of the vertical end face; clamping and fixing the two sub-shells on the same side of the vertical middle plane on the workbench respectively and precision turning the vertical end face, the inner hole and the inner hole shoulder face; fixing the two sub-shells on the lower side of the horizontal middle plane by closing them together left and right, assembling the four sub-shells with the fixed seats respectively, hoisting the two sub-shells on the upper side of the horizontal middle plane to the upper part of the corresponding sub-shells respectively and fixing them in a circular manner. The present invention effectively reduces the machining height and makes full use of the existing machining equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of machining, and particularly relates to a segmented machining method for a large four-lobe shell workpiece. Background Art

[0002] With the continuous upgrading of high-end assembly manufacturing industries such as military products and nuclear power products, the external dimensions of the core components in the products are constantly increasing, and the resources of large machining equipment suitable for processing such parts are limited. In order to reduce the dependence on large machining equipment during the machining process, process methods such as segmented machining, designing machining references, and general assembly and repair are required.

[0003] For example Figure 1 For the workpiece shown, a through inner hole is formed inside, and it has a vertical middle plane and a horizontal middle plane. During machining, the workpiece is divided into four parts: upper left, lower left, upper right, and lower right, which are machined separately and then assembled. Currently, the traditional machining method is to first rough mill the vertical middle plane of the four-lobe shell, then assemble the upper left and lower left shells and the upper right and lower right shells respectively and finish turn the vertical middle plane, then assemble the upper left and upper right shells and the lower left and lower right shells respectively and finish turn the horizontal middle plane, and finally perform the overall assembly of the four parts and then perform vertical turning

[0004] In the traditional machining method, the turning diameter of the workpiece after the overall assembly of the four parts is too large, which requires too high requirements for the machining site, and the existing machining equipment is difficult to meet the requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a segmented machining method for a large four-lobe shell workpiece, so as to solve the technical problems in the prior art that the turning diameter of the workpiece is too large after the overall assembly of the four parts in the traditional machining method, which requires too high requirements for the machining site, and the existing machining equipment is difficult to meet the requirements.

[0006] In order to achieve the above purpose, the technical solution of the present invention is:

[0007] A segmented machining method for a large four-lobe shell workpiece, the large four-lobe shell workpiece includes a shell, a horizontally extending bearing block is fixed inside the shell, a through inner hole is formed inside the bearing block along the horizontal direction, the shell has vertical end faces at both ends and a vertical middle plane and a horizontal middle plane in the middle, and the shell and the bearing block are both divided into four parts by the vertical middle plane and the horizontal middle plane, each part includes a sub-shell and a sub-bearing block, and the segmented machining method includes:

[0008] Rough mill the horizontal middle planes of the four sub-shells and the sub-bearing blocks respectively, take the middle line of the sub-bearing block as the reference, mill radial reference planes on both sides, and mill axial reference planes on both sides of the vertical middle plane;

[0009] Fix the two sub - shells on the same side of the vertical mid - plane into a circular shape, and finish - machine the vertical mid - plane and the vertical end - face;

[0010] Assemble and fix the two sub - shells on the same side of the horizontal mid - plane, finish - machine the horizontal mid - plane and the bearing seat, and finish - machine the vertical end - face and the reference inner hole of the vertical end - face;

[0011] Clamp and fix the two sub - shells on the same side of the vertical mid - plane on the workbench respectively, with the horizontal mid - plane perpendicular to the workbench. After the two sub - shells are respectively positioned and calibrated, fix them into a circular shape as a whole, and finish - turn the vertical end - face, the inner hole and the inner - hole shoulder face;

[0012] Close and fix the two sub - shells on the lower side of the horizontal mid - plane from left to right, assemble the four sub - shells with the fixed seat respectively, hoist the two sub - shells on the upper side of the horizontal mid - plane to the corresponding positions above the sub - shells respectively, and fix them into a circular shape respectively.

[0013] In one or more embodiments, the steps of respectively rough - milling the horizontal mid - plane and the sub - bearing seat of the four sub - shells, taking the mid - line of the sub - bearing seat as the reference, milling the radial reference planes on both sides of the horizontal mid - plane, and milling the axial reference planes on both sides of the vertical mid - plane include:

[0014] Leave a semi - finishing allowance, rough - mill the horizontal mid - plane of the sub - shell, and drill and tap the connecting bolt holes on the horizontal mid - plane;

[0015] Leave a semi - finishing allowance, mill the bearing seat;

[0016] Taking the mid - line of the bearing seat as the reference, mill the radial reference planes on both sides, and mill the axial plane references on both sides of the vertical mid - plane.

[0017] In one or more embodiments, the steps of fixing the two sub - shells on the same side of the vertical mid - plane into a circular shape and finish - machining the vertical mid - plane and the vertical end - face include:

[0018] Level the support platform to the same height, place the sub - shell below one side of the vertical mid - plane on the support platform, and preliminarily detect the flatness of the horizontal mid - plane with a level gauge ≤ 0.05mm;

[0019] Place the sub - shell above one side of the vertical mid - plane on the assembly platform, ensure that the radial reference planes on both sides are aligned, and the axial plane references on both sides of the vertical mid - plane are flush, with the flatness of each reference plane ≤ 0.05mm;

[0020] Use a feeler gauge to detect and ensure that the gap of the horizontal mid - plane joint surface ≤ 0.05mm;

[0021] Insert the process bolt, pre-tighten it according to the torque requirement, match and drill the taper pin holes, and install the positioning pins for fixation;

[0022] Lift and install it onto the workbench, with the vertical end face facing upwards, level it and then clamp it;

[0023] Leave a 4-mm allowance on one side, and successively rough-turn and semi-finish-turn the vertical end face;

[0024] After turning it over, level it according to the vertical end face, and finish-turn the vertical mid-plane to ensure that the flatness is better than 0.05 mm.

[0025] In one or more embodiments, the steps of assembling and fixing the two sub-shells located on the same side of the horizontal mid-plane, and finely machining the horizontal mid-plane and the bearing seats, and the vertical end face and the reference inner hole of the vertical end face include:

[0026] Place equal-height blocks on the workbench;

[0027] Lift and install the two sub-shells located on the same side of the horizontal mid-plane onto the equal-height blocks, with the horizontal mid-plane facing upwards;

[0028] Bring the two sub-shells located on the same side of the horizontal mid-plane together from left to right, insert bolts through the vertical mid-plane for fastening, correct them with the bearing seats and the horizontal mid-plane as the reference, drill and ream the positioning pin holes and install taper pins for positioning;

[0029] Use a feeler gauge to detect and ensure that the clearance of the vertical mid-plane joint surface is ≤ 0.05 mm;

[0030] Level it with the horizontal mid-plane as the reference, calibrate the perpendicularity of the vertical mid-plane, and calibrate the axis center with the symmetric center line of the bearing seats to ensure that the alignment accuracy is ≤ 0.05 mm and then press and fix it firmly;

[0031] Successively semi-finish and finish-mill the horizontal mid-plane;

[0032] Successively semi-finish and finish-mill the bearing seats;

[0033] Finish-mill the reference inner hole and the vertical end face.

[0034] In one or more embodiments, a cross keyway is provided on the bearing seat;

[0035] The steps of respectively clamping and fixing the two sub-shells located on the same side of the vertical mid-plane on the workbench, with the horizontal mid-plane perpendicular to the workbench, respectively positioning and calibrating the two sub-shells and then fixing them together by closing the circle, and finely turning the vertical end face, the inner hole and the inner hole shoulder surface include:

[0036] Place shims on the workbench;

[0037] Lift one of the sub - shells located on one side of the vertical mid - plane onto the shims. The horizontal mid - plane is set perpendicular to the workbench. Adjust the shims to correct the perpendicularity of the horizontal mid - plane, the straightness and flatness of the cross - keyway of the bearing journal, the flatness of the vertical mid - plane, and the roundness of the reference inner hole. The required correction accuracy is ≤0.05 mm. Clamp and fix it on the workbench, and assemble it with the cross - keyway of the bearing journal on the sub - shell using a keyway position gauge, and level and firmly fix it;

[0038] Lift the other sub - shell located on one side of the vertical mid - plane. After centering according to the keyway position gauge, place it on the shims, and calibrate the flatness of the vertical mid - plane and the vertical reference inner hole. The correction accuracy is ≤0.05 mm;

[0039] Fasten the horizontal mid - planes of the two sub - shells with connecting hole bolts and pre - tighten them according to the torque requirements;

[0040] Drill, ream and install positioning pin holes on the horizontal mid - plane for axial positioning;

[0041] Use a feeler gauge for detection to ensure that the clearance of the horizontal mating surface is ≤0.03 mm;

[0042] Set the end face of the reference inner hole facing upwards, round the inner hole, and level the vertical mid - plane to ensure the accuracy is ≤0.02 mm;

[0043] Rough - machine and finish - machine the end face, inner hole and inner hole shoulder surface;

[0044] After turning it over, correct it according to the finished - machined inner hole and vertical mid - plane, and rough - machine and finish - machine the inner hole and hole end face.

[0045] In one or more embodiments, the steps of fixing the two sub - shells located under the horizontal mid - plane together left and right, assembling the four sub - shells with the fixed seats respectively, lifting the two sub - shells located above the horizontal mid - plane to the corresponding sub - shells respectively, and closing and fixing them in a circular shape respectively include:

[0046] Bring the two sub - shells located under the horizontal mid - plane together left and right, and fasten the vertical mid - planes with bolts and tighten them according to the pre - tightening force;

[0047] Use a feeler gauge for detection to ensure that the clearance of the vertical mating surface is ≤0.05 mm;

[0048] Calibrate the coaxiality of the inner holes at both ends and install positioning pins for positioning;

[0049] Level the horizontal mid - plane to ensure that the flatness is better than 0.05 mm;

[0050] Assemble the four sub - shells with the fixed seats respectively;

[0051] Lift the two sub - shells located above the horizontal mid - plane, respectively group - circle them with the two sub - shells located below the horizontal mid - plane, and tighten them with bolts on the horizontal mid - plane according to the pre - tightening force;

[0052] Use a feeler gauge for inspection to ensure that the clearance of the horizontal mating surface ≤ 0.05 mm;

[0053] Install the positioning pins for positioning.

[0054] In one or more embodiments, after the steps of fixing the two sub - shells located below the horizontal mid - plane together left - and - right, assembling the four sub - shells with the fixed seat as a whole, hoisting the two sub - shells located above the horizontal mid - plane to the corresponding positions above the sub - shells respectively, and respectively closing and fixing the circles, the following steps are further included:

[0055] Measure the centers of the inner holes at both ends, fit out the reference axis as the assembly axis, and measure the symmetry error of the two sides of the fixed seat with respect to the center line according to the reference axis;

[0056] According to the symmetry error, trim the two sides of the fixed seat to ensure that the coaxiality after final assembly ≤ 0.05 mm.

[0057] Different from the prior art, the beneficial effects of the present application are:

[0058] 1. The two - section shell of the segmented processing method of the present application adopts the method of precision turning the inner hole in segments, effectively reducing the processing height, making full use of the existing processing equipment, overcoming the severe shortage of domestic resources of large - scale CNC turning and milling processing equipment, ensuring the product delivery schedule, reducing the manufacturing cycle from 180 days required by the original plan to 40 days, and saving about 6 million yuan in processing costs;

[0059] 2. The segmented processing method of the present application adopts a step - by - step processing method, and each process establishes a reasonable and effective processing and clamping reference for the next process, effectively improving the segmented processing accuracy;

[0060] 3. The workpiece processed by the segmented processing method of the present application can ensure the flatness accuracy of the horizontal mid - plane of 0.05 mm and the sealing test requirements after final assembly;

[0061] 4. The segmented processing method of the present application trims the fixed seat connected to the bearing seat according to the coaxial condition of the inner hole after final assembly, effectively eliminating the comprehensive error in the processing of the keyway of the bearing block of the shell and the final assembly process, and ensuring the coaxiality requirement of 0.05 mm between the inner hole of the bearing seat and the two ends of the inner hole after final assembly. Description of the Drawings

[0062] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0063] Figure 1 is a schematic structural diagram of a large four-lobe housing workpiece of the present application

[0064] Figure 2 is a schematic diagram of the corresponding state of step S100 of the present application.

[0065] Figure 3 is a schematic diagram of the corresponding state of step S200 of the present application.

[0066] Figure 4 is a schematic diagram of the corresponding state of step S300 of the present application.

[0067] Figure 5 is a schematic diagram of the corresponding state of step S400 of the present application. Specific Embodiments

[0068] The following will describe in detail the embodiments of the technical solutions of the present invention with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and thus are only examples and should not be used to limit the protection scope of the present invention.

[0069] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which the present invention belongs.

[0070] This application provides a segmented machining method for a large four-lobe housing workpiece, and the structure of the large four-lobe housing workpiece is as Figure 1 shown, including a housing, a horizontally extending bearing block is fixed inside the housing, an inner hole penetrating horizontally is formed inside the bearing block, the housing has vertical end faces 10 at both ends and vertical and horizontal middle planes 20 and 30 in the middle, and the housing and the bearing block are evenly divided into four parts by the vertical middle plane 20 and the horizontal middle plane 30, and each part includes a sub-housing 40 and a sub-bearing block 50.

[0071] The segmented machining method includes:

[0072] S100 Rough mill the horizontal middle planes 30 of the four sub-housings 40 and the sub-bearing blocks 50 respectively. Taking the center line of the sub-bearing block 50 as the reference, mill the radial reference planes 60 on both sides, and mill the axial reference planes on both sides of the vertical middle plane 20.

[0073] In one embodiment, please refer to Figure 2 , the above steps include:

[0074] Leave semi-finish allowance, rough mill the horizontal middle surface 30 of the sub-shell 40, and drill and tap the connecting bolt holes on the horizontal middle surface 30.

[0075] Leave semi-finish allowance and mill the bearing seats.

[0076] Taking the center line of the bearing seat as the reference, mill the radial reference surfaces 60 on both sides, and mill the axial plane reference surfaces 70 on both sides of the vertical middle surface 20.

[0077] By taking the center line of the bearing seat as the reference, milling the radial reference surfaces 60 on both sides and milling the axial plane reference surfaces 70 on the vertical middle surface 20, it provides radial and axial alignment references for the next process of assembling the circles.

[0078] S200 combines and fixes the two sub-shells 40 on the same side of the vertical middle surface 20, and finely processes the vertical middle surface 20 and the vertical end surface 10.

[0079] In one embodiment, refer to Figure 3 , the above steps include:

[0080] Level the support platform to the same height, place the sub-shell 40 below one side of the vertical middle surface 20 on the support platform, and preliminarily detect the flatness of the horizontal middle surface 30 ≤ 0.05 mm with a level.

[0081] Place the sub-shell 40 above one side of the vertical middle surface 20 on the assembly platform, ensure that the radial reference surfaces 60 on both sides are aligned, and the axial plane reference surfaces 70 on both sides of the vertical middle surface 20 are flush, and the flatness of each reference surface ≤ 0.05 mm.

[0082] Use a feeler gauge to detect and ensure that the joint surface gap of the horizontal middle surface 30 ≤ 0.05 mm.

[0083] Insert the process bolts, pre-tighten according to the torque requirements, match the taper pin holes, and install the positioning pins for fixation.

[0084] Lift and install it on the workbench, with the vertical end surface 10 facing up, level it and then clamp it.

[0085] Leave 4 mm allowance on one side, and rough turn and semi-finish turn the vertical end surface 10 in sequence.

[0086] After turning it over, level it according to the vertical end surface 10, and finely turn the vertical middle surface 20 to ensure that the flatness is better than 0.05 mm.

[0087] The upper and lower shell petals are aligned according to the radial reference plane 60 and the axial plane reference 70 and are closed by bolts. Then, a taper pin hole is drilled in the horizontal center plane 30. By installing the locating pin, the linear motion of the shell in the three axes X, Y, and Z and the rotational motion around the axis are restricted, ensuring that the two shell petals can be accurately positioned during subsequent processing and disassembly and assembly to prevent displacement and misalignment.

[0088] The vertical center dividing surface 20 is precision-turned to ensure that the vertical center dividing surface 20 has the same reference after the left and right sides are closed, so that the vertical sealing surface gap is less than 0.05mm after the four-petal assembly, meeting the assembly sealing test requirements; at the same time, it also provides a correction reference and axial processing reference for the subsequent precision milling of the bearing gear and precision turning of the inner hole, ensuring that the axial dimensions of the upper and lower shell bearing gears are consistent after the four-petal assembly.

[0089] S300 assembles and fixes two sub-shells 40 located on the same side of the horizontal center dividing surface 30, fine-machines the horizontal center dividing surface 30 and the bearing stop, and fine-machines the vertical end surface 10 and the reference inner hole of the vertical end surface 10;

[0090] In one embodiment, see Figure 4 , the above steps include:

[0091] The workbench is placed on high-speed rail;

[0092] Hoist the two sub-shells 40 located on the same side of the horizontal mid-dividing plane 30 onto the equal-height railway, with the horizontal mid-dividing plane 30 facing upwards;

[0093] Close the two sub-shells 40 on the same side of the horizontal center plane 30, insert the bolts into the vertical center plane 20 to close them, calibrate them based on the bearing block and the horizontal center plane 30, drill and hinge the positioning pin holes and install the taper pins for positioning;

[0094] Use a feeler gauge to check to ensure that the clearance between the vertical center plane 20 joints is ≤ 0.05mm;

[0095] Use the horizontal center plane 30 as the reference for leveling, the vertical center plane 20 for calibration of verticality, the symmetrical center line of the bearing gear for calibration of the axis center, and ensure that the alignment accuracy is ≤0.05mm before pressing and fixing;

[0096] Semi-finishing and finishing milling of horizontal center plane 30 in sequence;

[0097] Semi-finishing and finishing milling of bearing gears in sequence;

[0098] Finish milling of the vertical reference end face and reference inner hole.

[0099] The horizontal split surface 30 and the bearing journals of the housing in the left-right closed state are machined in one clamping, which can effectively ensure the overall flatness of the horizontal split surface 30 after the four-piece assembly and solve the housing sealing problem after assembly; the bearing journals are finely machined in the left-right closed state of the housing, with the vertical joint surface as the reference. Since the vertical split surface 20 is machined in one pass on the vertical lathe during circular assembly, the axial dimensions of the bearing journals after the four-piece assembly are ensured to be consistent.

[0100] S400 clamps and fixes the two sub-housings 40 located on the same side of the vertical split surface 20 to the workbench respectively. The horizontal split surface 30 is arranged perpendicular to the workbench. After the two sub-housings 40 are respectively positioned and calibrated, they are fixed together by closing the circle, and the vertical split surface 20, the vertical end face 10, the inner hole and the inner hole shoulder surface are finely turned.

[0101] In one embodiment, please refer to Figure 5 , and there is a cross keyway on the bearing journal.

[0102] The above steps include:

[0103] Place the shims on the workbench;

[0104] Lift and place one sub-housing 40 located on one side of the vertical split surface 20 onto the shims. The horizontal split surface 30 is arranged perpendicular to the workbench. Adjust the shims to correct the perpendicularity of the horizontal split surface 30, the straightness and flatness of the cross keyway of the bearing journal, the flatness of the vertical split surface 20 and the roundness of the inner hole. The required calibration accuracy is ≤0.05 mm. Clamp and fix it on the workbench, assemble it with the cross keyway of the bearing journal on the sub-housing 40 using the keyway position gauge, and level and fix it firmly;

[0105] Lift and place the other sub-housing 40 located on one side of the vertical split surface 20. After centering according to the keyway position gauge, place it on the shims, and calibrate the flatness of the vertical split surface 20 and the vertical reference inner hole. The calibration accuracy is ≤0.05 mm;

[0106] Fasten the horizontal split surfaces 30 of the two sub-housings 40 with the connecting hole bolts and pre-tighten them according to the torque requirements;

[0107] Drill, ream and install the positioning pin holes on the horizontal split surface 30 and axially position the positioning pins;

[0108] Use a feeler gauge to detect and ensure that the clearance of the horizontal mating surface is ≤0.03 mm;

[0109] Set the reference end face upward, align the circle according to the reference inner hole, and level the vertical split surface 20 to ensure the accuracy is ≤0.02 mm;

[0110] Roughly and finely turn the end face, inner hole and inner hole shoulder surface;

[0111] After turning over, correct according to the finely turned inner hole and the vertical vertical split surface 20, and roughly and finely turn the inner hole and the hole end face at the other end.

[0112] The upper / lower circular assembly of the housing is carried out on a vertical lathe. The horizontal middle plane 30 of the lower half housing is aligned vertically with the workpiece table, and then the upper half housing is hoisted according to the process requirements. Using a 180 0 The keyway position gauge is used to control the symmetry accuracy of the bearing journal keyway with respect to the inner hole after circular assembly.

[0113] The two sub-housings 40 located on the lower side of the horizontal middle plane 30 are closed and fixed left and right by S500. The four sub-housings 40 are respectively assembled with the fixed seat as a whole. The two sub-housings 40 located on the upper side of the horizontal middle plane 30 are respectively hoisted above the corresponding sub-housings 40 and circularly assembled and fixed respectively.

[0114] In one embodiment, the above steps include:

[0115] The two sub-housings 40 located on the lower side of the horizontal middle plane 30 are closed left and right, and the vertical middle plane 20 is bolted and tightened according to the pre-tightening force;

[0116] A feeler gauge is used for detection to ensure that the clearance of the vertical mating surface ≤ 0.05 mm;

[0117] The coaxiality of the inner holes at both ends is calibrated and positioning pins are inserted for positioning;

[0118] The horizontal middle plane 30 is leveled to ensure that the flatness is better than 0.05 mm;

[0119] The four sub-housings 40 are respectively assembled with the fixed seat as a whole;

[0120] The two sub-housings 40 located on the upper side of the horizontal middle plane 30 are hoisted and circularly assembled with the two sub-housings 40 located on the lower side of the horizontal middle plane 30 respectively, and bolted and tightened according to the pre-tightening force on the horizontal middle plane 30;

[0121] A feeler gauge is used for detection to ensure that the clearance of the horizontal mating surface ≤ 0.05 mm;

[0122] Positioning pins are inserted for positioning.

[0123] In one embodiment, the following steps are further included:

[0124] Measure the centers of the inner holes at both ends, fit the reference axis as the assembly axis, and measure the symmetry error of the two sides of the fixed seat with respect to the center line according to the reference axis;

[0125] According to the symmetry error, the two sides of the fixed seat are trimmed to ensure that the coaxiality after final assembly ≤ 0.05 mm.

[0126] According to the coaxial condition of the inner holes after final assembly, the fixed seat connected to the bearing seat is trimmed to effectively eliminate the comprehensive errors in the machining process and assembly process of the housing bearing journal keyway after final assembly, and ensure that the coaxiality requirement of the inner hole of the bearing seat and the inner holes at both ends after final assembly is 0.05 mm.

[0127] In the description of the present invention, a large number of specific details are set forth. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail so as not to obscure the understanding of this description.

[0128] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. And these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A segmented machining method for a large four-lobe shell workpiece, characterized in that, The large four-lobe shell workpiece includes a shell, inside which a horizontally extending bearing block is fixed. An inner hole running through horizontally is formed inside the bearing block. The shell has vertical end faces at both ends, as well as a vertical mid-plane and a horizontal mid-plane in the middle. The shell and the bearing block are both divided into four parts by the vertical mid-plane and the horizontal mid-plane. Each part includes a sub-shell and a sub-bearing block. The segmented machining method includes: Rough mill the horizontal mid-planes of the four sub-shells and the sub-bearing blocks respectively. Taking the mid-line of the sub-bearing block as the reference, mill the radial reference planes on both sides, and mill the axial plane references on both sides of the vertical mid-plane; Fix the two sub-shells on the same side of the vertical mid-plane together in a circular shape, and finish machine the vertical mid-plane and the vertical end faces; Assemble and fix the two sub-shells on the same side of the horizontal mid-plane together, finish machine the horizontal mid-plane and the bearing block, and finish machine the vertical end faces and the reference inner holes of the vertical end faces; Clamp and fix the two sub-shells on the same side of the vertical mid-plane on the workbench respectively. The horizontal mid-plane is set perpendicular to the workbench. After the two sub-shells are respectively positioned and calibrated, fix them together in a circular shape, and precision turn the vertical end faces, the inner holes and the inner hole shoulder faces; Closely fix the two sub-shells on the lower side of the horizontal mid-plane together left and right. Assemble the four sub-shells with the fixed seats respectively. Lift and place the two sub-shells on the upper side of the horizontal mid-plane above the corresponding sub-shells respectively, and fix them together in a circular shape respectively.

2. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that The step of respectively rough milling the horizontal mid-planes of the four sub-shells and the sub-bearing blocks, taking the mid-line of the sub-bearing block as the reference, milling the radial reference planes on both sides of the horizontal mid-plane, and milling the axial plane references on both sides of the vertical mid-plane includes: Leave a semi-finishing allowance, rough mill the horizontal mid-plane of the sub-shell, and drill and tap the connecting bolt holes on the horizontal mid-plane; Leave a semi-finishing allowance and mill the bearing block; Taking the mid-line of the bearing block as the reference, mill the radial reference planes on both sides, and mill the axial plane references on both sides of the vertical mid-plane.

3. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that, The step of fixing the two sub-shells on the same side of the vertical mid-plane together in a circular shape and finishing machining the vertical mid-plane and the vertical end faces includes: Adjust the support platform to be horizontally level. Place the sub-shell below one side of the vertical mid-plane on the support platform, and preliminarily detect the flatness of the horizontal mid-plane with a level gauge ≤ 0.05 mm; Place the sub-shell above one side of the vertical mid-plane on the assembly platform, ensure that the radial reference planes on both sides are aligned, and the axial plane references on both sides of the vertical mid-plane are flush. The flatness of each reference plane ≤ 0.05 mm; Use a feeler gauge to detect and ensure that the gap of the horizontal mid-plane joint surface ≤ 0.05 mm; Insert the process bolts, pre-tighten them according to the torque requirements, match and drill the taper pin holes, and install the positioning pins to fix; Lift it onto the workbench, turn the vertical end face upwards, level it and then clamp it; Leave a 4 mm allowance on one side, rough turn and semi-finish turn the vertical end face in sequence; After turning it over, level it according to the vertical end face, and precision turn the vertical mid-plane to ensure that the flatness is better than 0.05 mm.

4. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that The steps of assembling and fixing the two sub-cases on the same side of the horizontal mid-plane, and finely machining the horizontal mid-plane and the bearing seats, and finely machining the vertical end faces and the reference inner holes of the vertical end faces include: Place equal-height iron on the workbench; Lift the two sub-cases on the same side of the horizontal mid-plane onto the equal-height iron with the horizontal mid-plane facing upward; Bring together the two sub-cases on the same side of the horizontal mid-plane from left to right, insert bolts through the vertical mid-plane for fastening, align with the bearing seats and the horizontal mid-plane as the reference, drill and ream the positioning pin holes and install taper pins for positioning; Use a feeler gauge for inspection to ensure that the clearance of the vertical mid-plane joint surface is ≤0.05 mm; Level with the horizontal mid-plane as the reference, calibrate the perpendicularity of the vertical mid-plane, align the axis center of the symmetric center line of the bearing seats, and press firmly for fixation after ensuring that the alignment accuracy is ≤0.05 mm; Rough-mill and finish-mill the horizontal mid-plane in sequence; Rough-mill and finish-mill the bearing seats in sequence; Finish-mill the reference inner holes and the vertical end faces.

5. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that, There are cross keyways on the bearing seats; The steps of respectively clamping and fixing the two sub-cases on the same side of the vertical mid-plane on the workbench, with the horizontal mid-plane perpendicular to the workbench, respectively positioning and calibrating the two sub-cases and then fixing them as a whole by closing the circle, and finely turning the vertical end faces, the inner holes and the inner hole shoulder faces include: Place shims on the workbench; Lift one of the sub-cases on one side of the vertical mid-plane onto the shims with the horizontal mid-plane perpendicular to the workbench, adjust the shims to correct the perpendicularity of the horizontal mid-plane, the straightness and flatness of the cross keyways of the bearing seats, the flatness of the vertical mid-plane and the inner hole end faces, with the required calibration accuracy ≤0.05 mm, clamp and fix on the workbench and assemble with the cross keyways of the bearing seats on the sub-case using a keyway position gauge, level and fix firmly; Lift the other sub-case on one side of the vertical mid-plane, place it on the shims after centering according to the keyway position gauge, and calibrate the flatness of the vertical mid-plane and the vertical reference inner holes, with the calibration accuracy ≤0.05 mm; Fasten the horizontal mid-planes of the two sub-cases with connecting hole bolts and pre-tighten according to the torque requirements; Drill, ream and install positioning pins for axial positioning in the horizontal mid-plane; Use a feeler gauge for inspection to ensure that the horizontal mating surface clearance is ≤0.03 mm; Set the inner hole end face upward, round according to the reference inner hole, level the vertical mid-plane, and ensure the accuracy ≤0.02 mm; Rough-turn and finish-turn the end faces, inner holes and inner hole shoulder faces; After turning over, correct according to the reference inner hole and the vertical mid-plane, and rough-turn and finish-turn the other end face, inner hole and hole end face.

6. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that, The steps of bringing together and fixing the two sub-cases on the lower side of the horizontal mid-plane from left to right, respectively assembling the four sub-cases with the fixed seats as a whole, lifting the two sub-cases on the upper side of the horizontal mid-plane to the upper part of the corresponding sub-cases respectively, and respectively fixing them by closing the circle include: Bring together the two sub-cases on the lower side of the horizontal mid-plane from left to right, and tighten the bolts through the vertical mid-plane according to the pre-tightening force; Use a feeler gauge for inspection to ensure that the vertical mating surface clearance is ≤0.05 mm; Calibrate the coaxiality of both ends of the inner hole and install positioning pins for positioning; Level the horizontal mid-plane and ensure that the flatness is better than 0.05 mm; Assemble the four sub - shells with the fixed seat as a whole respectively; Lift and install the two sub - shells located above the horizontal mid - plane, and group - circle them with the two sub - shells located below the horizontal mid - plane respectively. Then, tighten them with bolts at the horizontal mid - plane according to the pre - tightening force; Use a feeler gauge to detect and ensure that the clearance of the horizontal mating surface is ≤ 0.05 mm; Install the positioning pins for positioning.

7. The segmented machining method of the large four-lobe shell workpiece according to claim 1, characterized in that After the steps of fixing the two sub - shells located below the horizontal mid - plane together left and right, assembling the four sub - shells with the fixed seat as a whole respectively, lifting the two sub - shells located above the horizontal mid - plane to the corresponding positions above the sub - shells respectively, and then group - circling and fixing them respectively, the following steps are further included: Measure the centers of the inner holes at both ends, fit the reference axis as the assembly axis, and measure the symmetry error of the two sides of the fixed seat with respect to the center line according to the reference axis; According to the symmetry error, trim the two sides of the fixed seat to ensure that the coaxiality after final assembly is ≤ 0.05 mm.

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