A method for processing a spherical shell head of a spacecraft fuel tank

Abstract

The present invention relates to a method for processing a spherical shell head of a spacecraft fuel tank, which belongs to the field of machining process technology. The method comprises the following steps: processing a process step at the open end of the spherical shell head; clamping an annular tool on a three-axis lathe, clamping the process step by the annular tool, rough-turning an inner profile by the three-axis lathe, flipping the spherical shell head 180 degrees and clamping it on the annular tool again, and rough-turning a second area by the three-axis lathe; installing an oblique tool on a three-axis milling machine, installing the spherical shell head on the oblique tool, and rough-milling a first area and a flange by the three-axis milling machine; removing the spherical shell head and leaving it to stand; installing the spherical shell head on the oblique tool again, and fine-milling the first area and the flange by the three-axis milling machine; clamping the spherical shell head on the annular tool, and fine-turning the inner profile by the three-axis lathe; clamping an inner support tool on the clamping jaws of the three-axis lathe, clamping the spherical shell head by the inner support tool, and fine-turning the second area by the three-axis lathe; cutting off the process step, and fine-turning the cut portion.

Description

Technical Field

[0001] The invention belongs to the technical field of machining processes, and in particular relates to a method for machining a spherical shell head of a spacecraft fuel tank. Background Art

[0002] like Figure 1 and Figure 2 As shown, the spherical shell head 100 of the spacecraft fuel tank is a spherical shell with an open end, and the end face of the open end is a plane. Two symmetrical flanges 110 are also provided on the outer surface of the spherical shell head 100. There is a certain angle between the central axis of the two flanges 100 and the end face of the open end. After production and molding, its outer surface, inner surface 120 and the outer wall of the flange 110 need to be turned and milled. Specifically, the outer surface of the spherical shell head 100 includes a first area 130 and a second area 140, wherein the first area 130 refers to the annular outer wall where the flange 110 is located, and the second area 140 refers to the outer wall of the outer surface except the first area 130. During processing, a lathe is usually used to turn the inner surface of the spherical shell head 100 and the above-mentioned second area 140, and a milling machine is used to mill the first area 130 of the spherical shell head 100.

[0003] At present, when processing the outer surface and the inner surface 120 of the spherical shell head 100, the workpiece is clamped by the clamping fixture of the machine tool so that the end face of the open end is parallel to the table of the machine tool processing table. In this way, there will be a certain angle between the axial direction of the flange 110 and the table of the machine tool processing table. Therefore, the three-axis machine tool cannot be used to turn and mill the part where the flange 110 and the outer surface of the spherical shell head 100 intersect, so only a five-axis machine tool can be used.

[0004] However, five-axis machine tools not only have the disadvantage of high cost, but also the two-axis linkage of the swing head during five-axis machine tool processing will lead to poor motion rigidity. Therefore, five-axis machine tools cannot perform large cutting depths. Therefore, when using five-axis machine tools to process spherical shell heads, there is also a technical problem of very long processing cycle. Summary of the Invention

[0005] The invention provides a method for machining a spherical shell head of a spacecraft fuel tank, which is used to solve the technical problem that the surface machining process of the spherical shell head of an aircraft fuel tank can only be completed by a five-axis machine tool.

[0006] The present invention is achieved through the following technical solutions: A method for processing a spherical shell head of a spacecraft fuel tank, comprising:

[0007] Step 1: Processing a process step at the open end of the spherical shell head;

[0008] Step 2: Clamp the annular tooling on the jaws of the three-axis lathe, use the annular tooling to clamp the process step and make the opening of the spherical shell head face upward, use the three-axis lathe to roughly turn the inner surface of the spherical shell head, then remove the spherical shell head and turn it 180° and clamp it back on the annular tooling so that the opening of the spherical shell head faces downward, and then use the three-axis lathe to roughly turn the second area of ​​the outer surface of the spherical shell head;

[0009] Step 3: Install the inclined fixture on the workbench of the three-axis milling machine, and install the rough-turned spherical shell head on the inclined fixture so that the axis of the flange on the spherical shell head is perpendicular to the workbench of the three-axis lathe. Use the three-axis milling machine to rough-mill the first area of ​​the spherical shell head and the outer wall of the flange;

[0010] Step 4: Remove the rough-milled spherical shell head and let it stand to eliminate the internal stress of the spherical shell head;

[0011] Step 5: Install the spherical shell head with internal stress eliminated on the inclined tooling in step 3 again, and use a three-axis milling machine to perform precision milling on the first area of ​​the spherical shell head and the outer wall of the flange;

[0012] Step 6: Clamp the spherical shell head after fine milling of the first area onto the annular fixture in step 2, so that the opening of the spherical shell head faces upward, and use a three-axis lathe to fine-turn the inner surface of the spherical shell head;

[0013] Step 7: Clamp the inner support fixture to the jaws of the three-axis lathe, use the inner support fixture to clamp the spherical shell head with the inner surface finish-turned, support the opening of the spherical shell head from the inside through the inner support fixture, and then use the three-axis lathe to finish-turn the second area of ​​the outer surface of the spherical shell head;

[0014] Step 8: After finishing turning the second area, remove the process step at the open end of the spherical shell head and finish turn the cut part.

[0015] Furthermore, in order to better implement the present invention, in step 1, the method of machining a process step at the open end of the spherical shell head includes:

[0016] The blank surplus of the blank is used to process an annular boss surrounding the opening on the outer side wall of the opening end of the spherical shell head, and a through hole is opened on the annular boss, and the annular boss constitutes the process step.

[0017] Furthermore, in order to better implement the present invention, the annular tooling includes a circular ring and a screw, and a screw hole is opened on the circular ring;

[0018] In step 2, the method of using an annular tool to clamp the process step includes:

[0019] Stack the process steps of the spherical shell head under the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. Pass the screws through the through holes from below and then screw them into the screw holes. Use the screws to press the process steps on the spherical shell head onto the bottom surface of the circular ring.

[0020] Furthermore, in order to better implement the present invention, in step 2, the method of re-clamping the spherical shell head onto the annular tooling includes:

[0021] Stack the process steps of the spherical shell head on top of the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. Pass the screws through the through holes from above and then screw them into the screw holes. Use the screws to press the process steps on the spherical shell head onto the top surface of the circular ring.

[0022] Further, in order to better implement the present invention, the inclined tooling includes a locking pin, a base frame for mounting on a workbench of a three-axis milling machine, a tilting frame obliquely arranged on the base frame, and a support rod supported between the tilting frame and the base frame, wherein a locking pin hole is provided on the tilting frame;

[0023] In step 3, the method for installing the spherical shell head on the oblique tooling includes:

[0024] Place the spherical shell head on the tilting frame so that the open end face of the spherical shell head and the process step are in contact with the inclined surface of the tilting frame. Pass the locking pin through the through hole on the process step and then pin it to the locking pin hole. Use the locking pin to lock the process step on the spherical shell head to the tilting frame.

[0025] Furthermore, in order to better implement the present invention, in step 3, the method of using a three-axis milling machine to rough mill the first area of ​​the spherical shell head and the outer wall of the flange includes:

[0026] First, make the axis of one of the flanges perpendicular to the worktable of the three-axis milling machine, and then use the three-axis milling machine to rough mill part of the first area and the outer wall of the flange, then remove the locking pin and rotate the spherical shell head 90° and then lock it with the locking pin, and then use the three-axis milling machine to rough mill another part of the first area, and then remove the locking pin again and rotate the spherical shell head 90° again and then lock it with the locking pin, and then use the three-axis milling machine to rough mill the remaining parts of the first area and the outer wall of the other flange, then remove the locking pin again and rotate the spherical shell head 90° again and then lock it with the locking pin, and finally use the three-axis milling machine to rough mill the remaining parts of the first area.

[0027] Furthermore, in order to better implement the present invention, in step 5, the method of fine milling the first area of ​​the spherical shell head and the outer wall of the flange using a three-axis milling machine includes:

[0028] First, make the axis of one of the flanges perpendicular to the worktable of the three-axis milling machine, and then use the three-axis milling machine to fine-mill part of the first area and the outer wall of the flange, then remove the locking pin and rotate the spherical shell head 90° and then lock it with the locking pin, and then use the three-axis milling machine to fine-mill another part of the first area, and then remove the locking pin again and rotate the spherical shell head 90° again and then lock it with the locking pin, and then use the three-axis milling machine to fine-mill the remaining part of the first area and the outer wall of the other flange, then remove the locking pin again and rotate the spherical shell head 90° again and then lock it with the locking pin, and finally use the three-axis milling machine to fine-mill the remaining part of the first area.

[0029] Furthermore, in order to better implement the present invention, in step 6, the method of clamping the spherical shell head onto the annular tooling includes:

[0030] Stack the process steps of the spherical shell head under the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. Pass the screws through the through holes from below and then screw them into the screw holes. Use the screws to press the process steps on the spherical shell head onto the bottom surface of the circular ring.

[0031] Furthermore, in order to better implement the present invention, the inner support tooling includes a circular plate, a convex ring and a pressure block, the convex ring is fixedly mounted on one side of the circular plate, and the convex ring is coaxially arranged with the circular plate, and the pressure block is mounted on the circular plate and located on the side of the convex ring;

[0032] In step 7, the method of clamping the spherical shell head using the inner support tooling includes:

[0033] The spherical shell head is turned upside down on the circular plate so that the outer ring wall of the convex ring is in contact with the inner wall of the opening of the spherical shell head, and then the process step is pressed by the pressing block.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The method for processing the spherical shell head of a spacecraft fuel tank provided by the present invention can complete the turning and milling processing of the outer surface and the inner surface of the spherical shell head by using a three-axis lathe and a three-axis milling machine, which is lower in cost. The three-axis lathe has higher kinematic rigidity than the five-axis lathe, so the three-axis machine tool can perform large cutting depth, thereby shortening the turning and milling processing cycle of the spherical shell head. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a structural diagram of a spherical shell head in the prior art (the dotted line in the figure represents the area dividing line);

[0038] Figure 2 yes Figure 1 Another perspective view of the spherical shell head shown;

[0039] Figure 3 Schematic diagram of the structure of a spherical shell head provided with process steps in an embodiment of the present invention;

[0040] Figure 4 1 is a schematic structural diagram of an annular tooling in an embodiment of the present invention;

[0041] Figure 5 This is a schematic structural diagram of a spherical shell head in an embodiment of the present invention installed on an annular fixture with the opening facing upward;

[0042] Figure 6 This is a schematic structural diagram of a spherical shell head in an embodiment of the present invention installed on an annular fixture with the opening facing downward;

[0043] Figure 7 2 is a schematic structural diagram of an oblique tooling in an embodiment of the present invention;

[0044] Figure 8 Schematic diagram of the installation structure of the spherical shell head on the oblique tooling in an embodiment of the present invention;

[0045] Figure 9 Schematic diagram of the structure of the spherical shell head in an embodiment of the present invention when it is processed on an inclined tooling and a three-axis milling machine;

[0046] Figure 10 Schematic diagram of the structure of the inner support tooling in an embodiment of the present invention;

[0047] Figure 11 Schematic diagram of the installation structure of the spherical shell head on the inner support tooling in an embodiment of the present invention;

[0048] Figure 12 yes Figure 11 a cross-sectional view of the structure shown;

[0049] Figure 13 yes Figure 12 A local enlarged view of area A;

[0050] Figure 14 The present invention provides a flowchart of a method for machining a spherical shell head of a spacecraft fuel tank.

[0051] In the picture:

[0052] 100-spherical shell head, 110-flange, 120-inner surface, 130-first area, 140-second area, 200-process step, 210-through hole, 300-annular tooling, 310-screw hole, 400-oblique tooling, 410-base, 420-tilt frame, 421-locking pin hole, 430-support rod, 500-inner support tooling, 510-circular plate, 520-convex ring, 530-pressure block. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0054] Example:

[0055] The spherical shell head processing method of a spacecraft fuel tank provided in this embodiment is used to process the spherical shell head 100 of a spacecraft fuel tank. The spherical shell head 100 has an open end, an inner surface 120 and an outer surface. Two symmetrical flanges 110 are provided on the outer surface. The outer surface includes a first area 130 and a second area 140, wherein the first area 130 refers to the annular outer side wall where the flange 110 is located, and the second area 140 refers to the outer side wall of the outer surface except the first area 130.

[0056] The processing method is as Figure 14 As shown, it includes the following steps:

[0057] Step 1: Processing a process step 200 at the open end of the spherical shell head 100 .

[0058] In this step, the method of processing the process step 200 at the open end of the spherical shell head 100 is specifically as follows: using the blank remainder of the blank to process a ring-shaped boss surrounding the opening on the outer side wall of the open end of the spherical shell head 100, such as Figure 3 As shown, a plurality of through holes 210 are opened on the annular boss, and the plurality of through holes 210 are evenly distributed along the circumference of the annular boss. The annular boss constitutes the above-mentioned process step 200, with the help of the process step 200, the open end of the spherical shell head 100 can be supported.

[0059] Step 2: Clamp the annular tooling 300 on the jaws of the three-axis lathe, use the annular tooling 300 to clamp the process step 200 and make the opening of the spherical shell head 100 face upward, use the three-axis lathe to roughly turn the inner surface 120 of the spherical shell head 100, then remove the spherical shell head 100 and turn it 180° and clamp it on the annular tooling 300 again, so that the opening of the spherical shell head 100 faces downward, and then use the three-axis lathe to roughly turn the second area 140 of the outer surface of the spherical shell head 100.

[0060] like Figure 4 As shown, the annular tooling 300 in this step includes a circular ring and several screws. Several screw holes 310 are opened on the circular ring. The size of the circular ring is adapted to the above-mentioned process step 200, and the positions of the several screw holes 310 correspond one-to-one to the several through holes 210.

[0061] In step 2, if Figure 5 As shown, the method of using the annular tooling 300 to clamp the process step 200 is specifically to dock the process step 200 of the spherical shell head 100 under the circular ring, so that the several through holes 210 on the process step 200 correspond one to one with the several screw holes 310 on the circular ring, and then the screws are passed through the through holes 210 from bottom to top and then screwed into the screw holes 310. Of course, one of the above-mentioned screws can be installed in each corresponding screw hole 310 and through hole 210, or the above-mentioned screws can be installed only in certain corresponding screw holes 310 and through holes 210. The process step 200 on the spherical shell head 100 is pressed against the bottom surface of the circular ring by the screw. At this time, the opening of the spherical shell head 100 is facing upward, and the tool head of the three-axis lathe passes through the circular ring from above and enters the interior of the spherical shell head 100 to rough-turn the inner surface 120 of the spherical shell head 100.

[0062] In step 2, if Figure 6 As shown, the method of re-clamping the spherical shell head 100 onto the annular tooling 300 is specifically to stack the process steps 200 of the spherical shell head 100 on top of the circular ring, so that the several through holes 210 on the process steps 200 correspond one to one with the several screw holes 310 on the circular ring, and then the screws are passed through the through holes 210 from top to bottom and then screwed into the screw holes 310. Of course, one of the above-mentioned screws can be installed in each corresponding screw hole 310 and through hole 210, or the above-mentioned screws can be installed only in certain corresponding screw holes 310 and through holes 210, and the process steps 200 on the spherical shell head 100 are pressed against the top surface of the circular ring by the screws. At this time, the opening of the spherical shell head 100 is facing downward, and the tool head of the three-axis lathe acts directly on the second area 140 of the outer surface of the spherical shell head 100 from above to rough-turn the second area 140.

[0063] The annular fixture 300 is used to clamp the process step 200 on the spherical shell head 100, and then the annular fixture 300 is clamped to the jaws of the three-axis lathe. In this way, the jaws on the machine tool can avoid direct contact with the spherical shell head 100 and damage to the spherical shell head 100. The provision of the process step 200 can also support the opening of the spherical shell head 100, making it less likely to deform during the rough turning process.

[0064] Step 3: Install the inclined tooling 400 on the workbench of the three-axis milling machine, and install the rough-turned spherical shell head 100 on the inclined tooling 400, so that the axis of the flange 110 on the spherical shell head 100 can be perpendicular to the workbench of the three-axis lathe, and use the three-axis milling machine to rough-mill the first area 130 of the spherical shell head 100 and the outer wall of the flange 110.

[0065] The above-mentioned inclined fixture 400 is an important component for implementing the method provided in this embodiment. Its main function is to enable the spherical shell head 100 to be clamped obliquely on the workbench of the three-axis milling machine so that the axis of the flange 110 on the spherical shell head 100 can be perpendicular to the workbench of the three-axis milling machine. Specifically, when the spherical shell head 100 is installed at a certain position on the inclined fixture, the axis of one of the flanges 110 on the spherical shell head 100 is perpendicular to the workbench of the three-axis milling machine. When the spherical shell head 100 is rotated 180° on the inclined fixture, the axis of the other flange 110 is perpendicular to the workbench of the three-axis milling machine. When the axis of the flange 110 is perpendicular to the workbench of the three-axis milling machine, the three-axis milling machine can be used to mill the outer wall of the flange 110 and the part where the flange 110 meets the outer surface.

[0066] Alternatively, as Figure 7 、 Figure 8 as well as Figure 9 As shown, the inclined tooling 400 in this embodiment includes a locking pin, a base 410, a tilting frame 420 and a support rod 430. The installation of the inclined tooling 400 on the workbench of the three-axis milling machine is specifically to install the base 410 on the workbench of the three-axis milling machine, and the tilting frame 420 is fixedly set on the base 410. The tilting frame 420 has an inclination angle of 40° relative to the base 410. The support rod 430 is supported between the base 410 and the tilting frame 420. The tilting frame 420 has an inclined surface. After installation, the angle between the tilting surface and the workbench of the three-axis milling machine is 40°. It should be noted that the angle between the central axis of the flange 110 on the spherical shell head 100 and the end face of the open end of the spherical shell head 100 is 50°.

[0067] In step 3, the method for installing the spherical shell head 100 on the inclined tooling 400 is specifically to place the spherical shell head 100 on the inclined frame 420 so that the open end surface of the spherical shell head 100 and the process step 200 are both in contact with the inclined surface of the inclined frame 420, and the locking pin is first passed through the through hole 210 on the process step 200 and then pinned to the locking pin hole 421, and the locking pin is used to lock the process step 200 on the spherical shell head 100 on the inclined frame 420. It should be noted that the locking pin holes 421 are provided on the inclined surface of the inclined frame 420, and the number of the locking pin holes 421 is also multiple, and the positions of the locking pin holes 421 correspond to the positions of the through holes 210 on the process step 200 of the spherical shell head 100. Since the angle between the inclined surface and the worktable of the three-axis milling machine is 40°, and the angle between the central axis of the flange 110 on the spherical shell head 100 and the end face of the open end of the spherical shell head 100 is 50°, through the above-mentioned installation method, it is possible to make the angle between the axial direction of one of the flanges 110 and the worktable of the three-axis milling machine be 90° at a certain installation position, and the three-axis milling machine can move up and down to mill the outer wall of the flange 110 and the position where the flange 110 and the outer surface are connected. Of course, in this step, the three-axis milling machine is used to rough mill the outer wall of the flange 110 and part of the first area 130 around the flange 110.

[0068] Specifically, in step 3, the method of using a three-axis milling machine to roughly mill the first region 130 of the spherical shell head 100 and the outer wall of the flange 110 is as follows:

[0069] First, make the axis of one of the flanges 110 perpendicular to the worktable of the three-axis milling machine, and then use the three-axis milling machine to rough mill part of the first area 130 and the outer wall of the flange 110, then remove the locking pin and rotate the spherical shell head 100 90° and then lock it with the locking pin, and then use the three-axis milling machine to rough mill another part of the first area 130, and then remove the locking pin again and rotate the spherical shell head 100 90° again and then lock it with the locking pin, and then use the three-axis milling machine to rough mill the remaining part of the first area 130 and the outer wall of the other flange 110, then remove the locking pin again and rotate the spherical shell head 100 90° again and then lock it with the locking pin, and finally use the three-axis milling machine to rough mill the remaining part of the first area 130. In this way, the outer walls of the two flanges 110 and the entire first area 130 are rough milled.

[0070] Step 4: Remove the rough-milled spherical shell head 100 and let it stand to eliminate the internal stress of the spherical shell head 100. It is worth noting that the internal stress of the spherical shell head 100 can be naturally eliminated during the standing process.

[0071] Step 5: The spherical shell head 100 with internal stress eliminated is mounted again on the inclined tooling 400 mounted on the three-axis milling machine, and the three-axis milling machine is used to perform fine milling on the first area 130 of the spherical shell head 100 and the outer wall of the flange 110. In this step, the fine milling method is specifically as follows:

[0072] First, the axis of one of the flanges 110 is made perpendicular to the worktable of the three-axis milling machine, and then the three-axis milling machine is used to fine-mill a portion of the first area 130 and the outer wall of the flange 110. Subsequently, the locking pin is removed and the spherical shell head 100 is rotated 90 degrees and then locked with the locking pin. Then, the three-axis milling machine is used to fine-mill another portion of the first area 130. Then, the locking pin is removed again and the spherical shell head 100 is rotated 90 degrees again and then locked with the locking pin. Then, the three-axis milling machine is used to fine-mill the remaining portion of the first area 130 and the outer wall of the other flange 110. Then, the locking pin is removed again and the spherical shell head 100 is rotated 90 degrees again and then locked with the locking pin. Finally, the three-axis milling machine is used to fine-mill the remaining portion of the first area 130. In this way, the outer walls of the two flanges 110 and the entire first area 130 are fine-milled.

[0073] During the above-mentioned rough milling and fine milling process, the inclined tooling 400 clamps the process step 200 and does not directly contact the spherical shell head 100, thereby further reducing damage to the spherical shell head 100 during the processing process and reducing the probability of deformation of the spherical shell head 100 during the rough milling and fine milling process.

[0074] Step 6: Clamp the spherical shell head 100, after the first region 130 has been finely milled, onto the annular fixture 300 mounted on the three-axis lathe, with the opening of the spherical shell head 100 facing upward. The inner surface 120 of the spherical shell head 100 is then fine-turned using the three-axis lathe. In this step, the spherical shell head 100 is clamped onto the annular fixture 300 by stacking the process step 200 of the spherical shell head 100 below the circular ring, so that the through-hole 210 on the process step 200 corresponds to the screw hole 310 on the circular ring. Screws are inserted from below through the through-hole 210 and then screwed into the screw hole 310. The screws are then used to press the process step 200 on the spherical shell head 100 against the bottom surface of the circular ring. After this step, the inner surface 120 of the spherical shell head 100 is machined.

[0075] Step 7: Clamp the inner support fixture 500 in the clamping jaws of the three-axis lathe, use the inner support fixture 500 to clamp the spherical shell head 100 with the inner surface 120 fine-turned, support the opening of the spherical shell head 100 from the inside through the inner support fixture 500, and then use the three-axis lathe to fine-turn the second area 140 of the outer surface of the spherical shell head 100.

[0076] After the above step 6, the wall thickness of the entire spherical shell head 100 becomes very thin. However, due to the supporting effect of the process step 200, the opening of the spherical shell head 100 can still remain circular. However, the wall of the spherical shell head 100 slightly away from the process step 200 is likely to undergo slight changes. If the above-mentioned annular tooling 300 is still used to clamp the spherical shell head 100 to the clamping jaws of the three-axis lathe, then the tool head of the three-axis lathe may not be able to completely finish turning the second area 140 near the process step 200. For this reason, the method provided in this embodiment uses an internal support tooling 500 to support the wall of the spherical shell head 100 near the process step 200 to prevent it from undergoing slight changes, so that the three-axis lathe can better finish turning the second area 140 near the process step 200.

[0077] Alternatively, as Figure 10 、 Figure 11 and Figure 12 As shown, the internal support tooling 500 in this embodiment includes a ring plate, a convex ring 520 and a pressure block 530. The convex ring 520 is fixed on one side plate surface of the ring plate 510, and the convex ring 520 is coaxially arranged with the ring plate 510. The pressure block 530 is installed on the ring plate 510 and is located on the side of the convex ring 520.

[0078] In step 7, the method of clamping the spherical shell head 100 using the internal support fixture 500 is specifically as follows: the spherical shell head 100 is flipped upside down on the circular plate 510 so that the outer ring wall of the protruding ring 520 is in contact with the inner wall of the opening of the spherical shell head 100, and then the process step 200 is pressed tightly using the pressing block 530. The pressing block 530 can be connected to the circular plate 510 by screws or connected to an external structure, as long as the process step 200 on the spherical shell head 100 can be pressed tightly using the pressing block 530.

[0079] By using the internal support fixture 500 to support the wall of the opening of the spherical shell head 100, it can not only ensure that the three-axis lathe can perform fine turning on the second area 140 on the outer surface, but also effectively reduce the probability of deformation of the spherical shell head 100 during the fine turning process. Figure 13 As shown, a convex ring is provided at the intersection of the convex ring 520 of the inner support tool 500 and the circular plate 510, and the convex ring is used to conform to the open end of the spherical shell head 100.

[0080] Step 8. After the fine turning of the second area 140 is completed, the spherical shell head 100 is still clamped on the inner support tooling 500, and then the process step 200 is cut off. At this time, the convex ring 520 of the inner support tooling 500 supports the wall at the opening of the spherical shell head 100, and then the cut-off part is fine turned. During this process, the supporting effect of the inner support tooling 500 on the cut-off head enables the lathe to act more accurately on the cut-off part, so that the outer surface of the entire spherical shell head 100 is finely processed.

[0081] Through the spherical shell head processing method of the spacecraft fuel tank provided in this embodiment, the turning and milling processing of the inner surface 120 and the outer surface of the spherical shell head only need a three-axis machine tool, thereby reducing the production cost of the spherical shell head 100. Because the motion rigidity of a three-axis lathe is higher than that of a five-axis lathe, the three-axis machine tool can perform a large cutting depth, thereby shortening the turning and milling processing cycle of the spherical shell head 100.

[0082] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for processing a spherical shell head of a spacecraft fuel tank, characterized in that: include: Step 1: Processing a process step (200) at the open end of the spherical shell head (100); Step 2: Clamp the annular tool (300) on the clamping jaws of the three-axis lathe, use the annular tool (300) to clamp the process step (200) and make the opening of the spherical shell head (100) face upward, use the three-axis lathe to roughly turn the inner surface (120), then remove the spherical shell head (100) and turn it 180 degrees and clamp it on the annular tool (300) again, make the opening of the spherical shell head (100) face downward, and then use the three-axis lathe to roughly turn the second area (140); Step 3: Install the inclined tool (400) on the workbench of the three-axis milling machine, and install the rough-turned spherical shell head (100) on the inclined tool (400) so that the axis of the flange (110) on the spherical shell head (100) can be perpendicular to the workbench of the three-axis lathe, and use the three-axis milling machine to roughly mill the first area (130) and the flange (110); Step 4: Remove the rough-milled spherical shell head (100) and let it stand to eliminate internal stress; Step 5: The spherical shell head (100) with internal stress eliminated is mounted on the inclined tooling (400) again, and the first region (130) and the flange (110) are finely milled using a three-axis milling machine; Step 6: Clamp the finely milled spherical shell head (100) onto the annular fixture (300) so that the opening of the spherical shell head (100) faces upward, and use a three-axis lathe to fine-turn the inner surface (120); Step 7: Clamp the inner support fixture (500) to the clamping jaws of the three-axis lathe, use the inner support fixture (500) to clamp the spherical shell head (100) that has been fine-turned, support the opening of the spherical shell head (100) from the inside through the inner support fixture (500), and then use the three-axis lathe to fine-turn the second area (140); Step 8: After finishing the second area (140), the process step (200) is removed and the removed portion is finished by finishing.

2. The method for processing the spherical shell head of a spacecraft fuel tank according to claim 1, characterized in that: In step 1, the method for machining a process step (200) at the open end of the spherical shell head (100) includes: A ring-shaped boss surrounding the opening is machined on the outer wall of the open end of the spherical shell head (100) by utilizing the blank surplus of the blank, and a through hole (210) is opened on the ring-shaped boss, and the ring-shaped boss constitutes the process step (200).

3. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 2, characterized in that: The annular tool (300) comprises a circular ring and a screw, wherein a screw hole (310) is provided on the circular ring; In step 2, the method of clamping the process step (200) using the annular tool (300) includes: The process step (200) is stacked below the circular ring so that the through hole (210) corresponds to the screw hole (310), and a screw is passed through the through hole (210) from below and then screwed into the screw hole (310), and the process step (200) is pressed onto the bottom surface of the circular ring by the screw.

4. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 3, characterized in that: In step 2, the method of re-clamping the spherical shell head (100) onto the annular tool (300) includes: The process step (200) is stacked on the top of the ring so that the through hole (210) corresponds to the screw hole (310), and the screw is passed through the through hole (210) from above and then screwed into the screw hole (310), and the process step (200) is pressed onto the top surface of the ring by the screw.

5. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 2, characterized in that: The inclined tool (400) comprises a locking pin, a base frame (410) for mounting on a workbench of a three-axis milling machine, an inclined frame (420) inclined on the base frame (410), and a support rod (430) supported between the inclined frame (420) and the base frame (410), wherein a locking pin hole (421) is provided on the inclined frame (420); In step 3, the method of installing the spherical shell head (100) on the inclined tool (400) includes: The spherical shell head (100) is placed on the tilting frame (420) so that the process step (200) is in contact with the inclined surface of the tilting frame (420). A locking pin is first passed through the through hole (210) on the process step (200) and then pinned to the locking pin hole (421). The locking pin is used to lock the process step (200) on the tilting frame (420).

6. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 5, characterized in that: In step 3, the method of rough milling the first region (130) and the flange (110) using a three-axis milling machine includes: First, the axis of one of the flanges (110) is made perpendicular to the workbench of the three-axis milling machine, and then the three-axis milling machine is used to roughly mill a portion of the first area (130) and the outer wall of the flange (110), then the locking pin is removed and the spherical shell head (100) is rotated 90 degrees and then locked with the locking pin, and then the three-axis milling machine is used to roughly mill another portion of the first area (130), and then the locking pin is removed again and the spherical shell head (100) is rotated 90 degrees again and then locked with the locking pin, and then the three-axis milling machine is used to roughly mill the remaining portion of the first area (130) and the outer wall of the other flange (110), and then the locking pin is removed again and the spherical shell head (100) is rotated 90 degrees again and then locked with the locking pin, and finally the three-axis milling machine is used to roughly mill the remaining portion of the first area (130).

7. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 6, characterized in that: In step 5, the method of fine milling the first region (130) and the flange (110) using a three-axis milling machine includes: First, the axis of one of the flanges (110) is made perpendicular to the worktable of the three-axis milling machine, and then the three-axis milling machine is used to fine-mill a portion of the first area (130) and the outer wall of the flange (110), and then the locking pin is removed and the spherical shell head (100) is rotated 90 degrees and then locked with the locking pin, and then the three-axis milling machine is used to fine-mill another portion of the first area (130), and then the locking pin is removed again and the spherical shell head (100) is rotated 90 degrees again and then locked with the locking pin, and then the three-axis milling machine is used to fine-mill the remaining portion of the first area (130) and the outer wall of the other flange (110), and then the locking pin is removed again and the spherical shell head (100) is rotated 90 degrees again and then locked with the locking pin, and finally the three-axis milling machine is used to fine-mill the remaining portion of the first area (130).

8. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 4, characterized in that: In step 6, the method of clamping the spherical shell head (100) onto the annular tool (300) includes: The process step (200) is stacked below the circular ring so that the through hole (210) corresponds to the screw hole (310), and a screw is passed through the through hole (210) from below and then screwed into the screw hole (310), and the process step (200) is pressed onto the bottom surface of the circular ring by the screw.

9. The method for machining the spherical shell head of a spacecraft fuel tank according to claim 2, characterized in that: The inner support tooling (500) comprises a circular plate (510), a convex ring (520) and a pressing block (530), wherein the convex ring (520) is fixedly mounted on a side surface of the circular plate (510), and the convex ring (520) and the circular plate (510) are coaxially arranged, and the pressing block (530) is mounted on the circular plate (510) and is located on the side of the convex ring (520); In step 7, the method of clamping the spherical shell head (100) using the inner support tool (500) includes: The spherical shell head (100) is placed upside down on the circular plate (510) so that the outer ring wall of the convex ring (520) is in contact with the inner wall of the opening of the spherical shell head (100), and then the process step (200) is pressed by the pressing block (530).

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