A method of machining a large diameter composite material engine skirt

Abstract

The application discloses a processing method of a large-diameter composite engine skirt, and comprises the following steps: according to the processing size requirement, a clamping and processing tool is designed and manufactured; the composite skirt is installed with the tool, and the run-out is detected in a natural state; the composite skirt is adjusted to meet the processing requirement; after the processing precision is verified through trial cutting, the outer circle hole of the composite skirt is processed formally; the composite skirt is turned over and hoisted, and the run-out is detected in a natural state; the composite skirt is adjusted to meet the processing requirement; and the end face hole of the composite skirt is processed. The application improves the machining route and method of the large-diameter engine shell skirt, realizes product processing by using existing equipment through special clamps, drill tools and other tools, reduces the requirement of product processing on equipment capacity, reduces the demand for equipment purchase, and effectively reduces the processing cost of the large-diameter engine shell skirt.

Description

Technical Field

[0001] This invention belongs to the field of rocket engine technology, specifically relating to a processing method for a large-diameter composite material engine skirt. Background Technology

[0002] The development and application of large heavy-lift rocket engines are of great significance to ensuring the smooth implementation of major projects such as manned spaceflight, space infrastructure construction, deep space exploration, and round-trip flights between Earth and space.

[0003] Heavy-lift launch vehicles are crucial transportation tools for manned spaceflight and deep space exploration. They are technologically advanced and complex, involving highly sophisticated industry support and manufacturing processes, making system integration extremely challenging. Large rocket engines have large components, resulting in extremely high procurement and maintenance costs for supporting equipment. Therefore, using relatively lower-cost equipment to process some components can effectively reduce production costs. Currently, heavy-lift rocket engines are mostly made of composite materials to reduce engine weight and increase payload. However, due to limitations in composite material molding and processing technology, composite skirt components are the most readily adjustable in terms of equipment requirements. Reducing the processing cost of the skirt is a key issue that needs to be addressed to lower the production cost of large-diameter composite material engines. Summary of the Invention

[0004] In view of the problems existing in the background technology, the purpose of this invention is to provide a processing method for large-diameter composite material engine skirts with low production cost.

[0005] To achieve the above objectives, the present invention provides a processing method for a large-diameter composite material engine skirt, comprising the following steps:

[0006] S1, Design and manufacture clamping and machining tooling according to the machining size requirements;

[0007] S2, install the composite skirt with the tooling, and detect vibration in a natural state;

[0008] S3, Adjust the composite skirt alignment to meet processing requirements;

[0009] S4. After trial cutting to verify that the machining accuracy meets the requirements, proceed with the formal machining of the outer circular holes of the composite skirt.

[0010] S5, flip-up suspended composite skirt, detects movement in natural state;

[0011] S6, Adjust the composite skirt alignment to meet processing requirements;

[0012] S7, machining the end face of the composite skirt.

[0013] Preferably, in step S2, the runout of the inner end face of the composite skirt flange under natural conditions is detected by dial gauge, and the runout value of the outer circle at a position 50mm away from the flange end face is measured.

[0014] A further preferred option is to use 16 evenly distributed jumps instead, with the 16 jump values ​​being detected at the same location.

[0015] Further optimization involves detecting the runout of the end face of the skirt flange at the processing position under natural conditions, requiring the runout to be no greater than 0.05mm.

[0016] Preferably, in step S3, the runout values ​​of the inner end face and outer circle of the large-diameter engine housing skirt flange are detected by dial gauge, and the tooling is adjusted according to the detection results until the processing requirements are met.

[0017] Preferably, in step S4, before performing the test cutting of the outer circle hole of the composite skirt, 16 center punches are made within 10mm of the outer circle from the end face, with the diameter and depth of the punches not exceeding 0.1mm.

[0018] A further preferred method is to use vernier calipers to measure the chord length of all adjacent striking points, requiring that the deviation of all chord lengths is no greater than 0.20mm.

[0019] Further optimization involves machining the outer circular holes of the large-diameter engine housing and monitoring the runout changes during the process to ensure that the machining accuracy meets the requirements.

[0020] Preferably, in step S5, after flipping and hoisting the composite skirt, the runout is detected in its natural state, and the runout value is required to be no greater than 0.05mm.

[0021] Preferably, in step S6, the runout of the end face to be processed of the large-diameter engine casing skirt and the circular runout of the end face hole drill bit are detected, and the alignment is adjusted to meet the processing requirements before clamping.

[0022] Further preferred, the runout of the end face of the skirt flange at the processing position under natural conditions is tested by dial indicator, and the runout of the end face within a range of 200×200mm is required to be no more than 0.05mm.

[0023] Preferably, in step S7, the composite skirt end face is machined using the pre-machined outer circular hole of the engine housing.

[0024] In a further preferred embodiment, the drill bit body is aligned with the outer circular hole of the composite skirt and assembled using connecting bolts. The runout of the entire circumference of the inner hole of the positioning drill bushing is no more than 0.01 mm, and the runout of the end face is no more than 0.02 mm.

[0025] The beneficial effects of this invention are: This invention improves the machining route and method for large-diameter engine casing skirts, and uses existing equipment to achieve product processing by using special fixtures, drilling tools and other tooling, which reduces the requirements for equipment capabilities in product processing, reduces equipment procurement needs, and effectively reduces the processing cost of large-diameter engine casing skirts. Attached Figure Description

[0026] Figure 1 This is a front view of the large-diameter engine casing skirt structure;

[0027] Figure 2 Top view of the large-diameter engine casing skirt structure;

[0028] Figure 3 Schematic diagram of the installation of the support components for boring machining;

[0029] Figure 4 This is a schematic diagram of a special lifting device;

[0030] Figure 5 Schematic diagram of drilling support components;

[0031] Figure 6 This is a schematic diagram of the drill string installation.

[0032] In the diagram: 1. Composite skirt; 2. Flange support assembly; 3. Pressure plate assembly; 4. Rounding assembly; 5. Rotary work platform; 6. Milling fixture installation assembly; 7. Lifting tool body; 8. Lifting screw assembly; 9. Locking screw assembly; 10. Support connecting rod; 11. Drill tool body; 12. Positioning drill bushing; 13. Positioning pin. Detailed Implementation

[0033] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] like Figures 1 to 6 As shown, for a certain type of large-diameter composite material engine composite skirt, its external dimensions are Φ3552×1250 and the column section wall thickness is 8. Its processing method and process are as follows:

[0035] Step 1: Based on the machining route and method for the large-diameter engine casing skirt, confirm the equipment's machining capabilities and create clamping and machining process equipment. Based on the existing equipment's machining capabilities and the dimensional requirements for the large-diameter engine casing skirt, design milling support components, drilling support components, external hole milling fixtures, end hole drilling tools, and special lifting tools, among other process equipment.

[0036] Based on the product's structural dimensions, a boring support assembly was designed to work with a 2m×2.5m rotary table to install the composite skirt and machine the outer circular holes of the composite skirt. A special lifting tool was designed for the composite skirt's flipping and lifting operations. A drilling support assembly was designed for machining and clamping the end holes of the composite skirt. A drilling tool was designed to drill the end holes of the composite skirt using the pre-machined outer circular holes.

[0037] Step 2: Select the appropriate equipment and tooling for machining the outer circular holes of the skirt to clamp the large-diameter engine housing skirt. Before machining the large-diameter engine housing skirt, install the milling support assembly on the rotary table of the boring and milling machine, and align the milling support assembly to meet the requirements; place the large-diameter engine housing skirt on the milling support assembly, and use the pressure plate to fix the skirt on the milling support assembly.

[0038] Based on the product's structural dimensions, design a boring support assembly. After installing the boring support assembly on a 2m×2.5m rotary table 5, place the composite skirt 1 on the assembly, with the composite skirt flange end face facing down and close to the flange support assembly 2. Use a dial indicator to check the runout of the inner end face of the skirt flange in its natural state, and the runout value of the outer circle at a position 50mm from the flange end face. It is permissible to replace it with 16 evenly distributed runouts, and the 16 runout values ​​should be checked at the same location.

[0039] Step 3: Adjust the tooling according to the alignment of the large-diameter engine housing skirt until the runout of the skirt end face and outer circle meets the machining requirements. Use a dial indicator to check the runout value of the inner end face and outer circle of the large-diameter engine housing skirt flange; clamp and adjust according to the runout value of the inner end face and outer circle of the large-diameter engine housing skirt measured by the dial indicator until the machining requirements are met; after the alignment is met, use a dial indicator to monitor the change of runout value on the inner end face and outer circle of the skirt.

[0040] Based on the measured runout values, 0.05mm copper shims were placed on the end faces of flange support assembly 2 and composite skirt 1 to adjust the end face runout. The rounding assembly 4 was installed on the inner cylindrical surface of composite skirt 1, ensuring the center of the pre-reserved notch on the rounding assembly 4 deviated from the center of the evenly distributed alignment starting point by no more than 5mm. The pre-tightening screws were adjusted to round the composite skirt, ensuring the runout of the entire outer circle was no more than 0.10mm. After alignment, the composite skirt 1 and flange support assembly 2 were pressed together using pressure plate assembly 3, and the milling fixture mounting assembly 6 and rotating work platform 5 were also pressed together. After confirming that the runout value still met the requirements, a dial indicator or lever gauge was placed on both the end face of the skirt flange and the outer circle to monitor the change in runout value during the process.

[0041] Step 4: Machining the outer circular holes of the large-diameter engine housing and monitoring the runout during the process. Perform trial cutting according to the dimensional requirements to confirm that the hole dimensions meet the requirements; machine the outer circular holes of the large-diameter engine housing skirt to the required dimensions and monitor the runout during the process.

[0042] Make 16 center punches evenly distributed within a 10mm range from the end face of the outer circle. The diameter and depth of the punches should not exceed 0.1mm. Use vernier calipers to measure the chord length of all adjacent punches, ensuring that the deviation of all chord lengths does not exceed 0.20mm. After confirming that the rotary indexing is accurate, perform a trial cut of the outer circle hole of the composite skirt 1, and observe the change in the runout value of the dial indicator or lever indicator. If it is an elastic runout change, and the indicator reading returns to its original position after machining, then continue machining to the specified dimensions.

[0043] Step 5: Select the appropriate equipment and tooling for machining the end face holes of the engine casing skirt to clamp the large-diameter engine casing skirt. Use a special lifting tool to flip and lift the large-diameter engine casing skirt; fix the end face hole drilling tool to the large-diameter engine casing skirt; use a special lifting tool to place the large-diameter engine casing skirt on the drilling support assembly.

[0044] Using a specialized lifting tool, lift and rotate the composite skirt 1. Wrap the lifting tool body 7 around the composite skirt 1 at a distance of 100-150mm from the flange end face. Connect the double lifting straps (each with a load capacity greater than 500kg) to the lifting screw assembly 8. After tightening the threads of the locking screw assembly 9, lift the composite skirt to a position 2000mm above the ground and rotate it so that the flange end face of the composite skirt 1 faces upwards. Connect and fix the base of the support connecting rod 10 to the fixed connecting seat on the bottom surface. Connect the upper part of the clamping screw to the composite skirt 1, and use the pressure plate assembly 3 to fix the composite skirt (avoiding the areas to be machined).

[0045] Step 6: Adjust the tooling according to the alignment of the large-diameter engine casing skirt to be machined, ensuring that the runout of the skirt end face and the tooling meets the machining requirements. Inspect the runout of the large-diameter engine casing skirt end face to be machined and the runout of the drill bit at the end face hole; adjust and align the large-diameter engine casing skirt end face to be machined and the drill bit at the end face hole until they meet the machining requirements, then clamp them.

[0046] The runout of the skirt flange at the processing position is tested using a dial indicator under natural conditions. The runout should not exceed 0.05mm within a 200×200mm range. If the runout does not meet the requirement, the threaded connection position between the pressure plate assembly 3 and the support connecting rod 10 is adjusted until the runout of the processing position is not greater than 0.05mm.

[0047] Step 7: Machining the hole dimensions on the end face of the large-diameter engine housing and monitoring the runout during the process. Perform trial cutting according to the dimensional requirements to confirm whether the hole dimensions meet the requirements; machine the large-diameter engine housing end face circular holes to the required dimensions and monitor the runout during the process.

[0048] Align the drill body 11 with the outer hole of the composite skirt 1, and assemble using connecting bolts. Ensure the runout of the inner hole of the positioning drill bushing 12 is no more than 0.01mm around the entire circumference and no more than 0.02mm on the end face. If the runout does not meet the requirements, place a 0.05mm feeler gauge between the mating surfaces of the drill body 11 and the outer circle of the composite skirt 1, and the flange mating surface. After ensuring the drill bushing runout meets the alignment requirements, tighten the connecting bolts and insert the positioning pin 13 into the positioning hole to lock the drill. Use a special step drill to machine the end holes of the front skirt. After machining, loosen the support connecting rod 10, and use a special lifting tool to rotate and lift the composite skirt 1. Machin the remaining 15 evenly distributed end holes.

[0049] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, substitutions, improvements, etc., made under the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for processing a large-diameter composite material engine skirt, characterized in that, Includes the following steps: S1, Design and manufacture clamping and machining tooling according to the machining size requirements; S2, install the composite skirt with the tooling, and detect vibration in a natural state; S3, Adjust the composite skirt alignment to meet processing requirements; S4. Before performing trial cutting of the outer diameter hole of the composite skirt, make 16 center punches within 10mm of the end face of the outer diameter. The diameter and depth of the punches should not exceed 0.1mm. Use vernier calipers to measure the chord length of all adjacent punches. The deviation of all chord lengths should not exceed 0.20mm. After confirming that the rotary indexing is accurate, perform trial cutting of the outer diameter hole of the composite skirt and observe the change in the dial indicator runout. If it is an elastic runout change, the dial indicator reading will return to its original position after processing. Then continue processing to the dimension. After verifying that the processing accuracy meets the requirements of the trial cutting, proceed with the formal processing of the outer diameter hole of the composite skirt. S5, flip-up suspended composite skirt, detects movement in natural state; S6, Adjust the composite skirt alignment to meet processing requirements; S7, machining the end face of the composite skirt.

2. The processing method for a large-diameter composite material engine skirt according to claim 1, characterized in that: In step S2, the runout of the inner end face of the composite skirt flange under natural conditions is detected by dial gauge, and the runout value of the outer circle at a position 50mm away from the flange end face is detected. It is permissible to replace it with 16 evenly distributed runouts, and the detection positions of the 16 runout values ​​are consistent.

3. The processing method for a large-diameter composite material engine skirt according to claim 2, characterized in that: The runout of the end face of the skirt flange at the processing position under natural conditions should be checked, and the runout should not exceed 0.05mm.

4. The processing method for a large-diameter composite material engine skirt according to claim 1, characterized in that: In step S3, the runout values ​​of the inner end face and outer circle of the large-diameter engine casing skirt flange are detected by dial gauge, and the tooling is adjusted according to the detection results until the processing requirements are met.

5. The processing method for a large-diameter composite material engine skirt according to claim 1, characterized in that: In step S5, after flipping and hoisting the composite skirt, the runout is detected in its natural state, and the runout value is required to be no greater than 0.05mm.

6. The processing method for a large-diameter composite material engine skirt according to claim 1, characterized in that: In step S6, the runout of the end face to be machined on the large-diameter engine casing skirt and the circular runout of the end face hole drill bit are detected, and the alignment is adjusted to meet the machining requirements before clamping.

7. The processing method for a large-diameter composite material engine skirt according to claim 6, characterized in that: The runout of the end face of the skirt flange at the processing position under natural conditions is tested by dial indicator. The runout of the end face within a range of 200×200mm is required to be no more than 0.05mm.

8. The processing method for a large-diameter composite material engine skirt according to claim 1, characterized in that: In step S7, the composite skirt end face is machined using the pre-machined outer circular hole of the engine housing; the drill body is aligned with the outer circular hole of the composite skirt, and assembled using connecting bolts, ensuring that the runout of the inner hole of the positioning drill bushing is no more than 0.01mm and the runout of the end face is no more than 0.02mm.

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