Machining method for spherical shell seal head of spacecraft fuel tank

Abstract

The invention relates to a method for machining a spherical shell seal head of a spacecraft fuel tank, which belongs to the technical field of machining processes and comprises the following steps: machining a process step at the open end of the spherical shell seal head; the annular tool is clamped on a three-axis lathe, the annular tool is used for clamping the process step, the three-axis lathe is used for roughly turning the inner molded surface, the spherical shell end socket is overturned by 180 degrees and then clamped on the annular tool again, and the three-axis lathe is used for roughly turning a second area; the inclined tool is installed on a three-axis milling machine, the spherical shell end socket is installed on the inclined tool, and the first area and the flange are roughly milled through the three-axis milling machine; taking down the spherical shell end socket and standing; the spherical shell end socket is installed on the inclined tool again, and the first area and the flange are subjected to finish milling through the three-axis milling machine; the spherical shell end socket is clamped to an annular tool, and the inner molded surface is subjected to finish turning through a three-axis lathe; an inner supporting tool is clamped to a clamping jaw of the three-axis lathe, the spherical shell end socket is clamped through the inner supporting tool, and the second area is subjected to finish turning through the three-axis lathe; and the process step is cut off, and the cut-off part is subjected to finish turning.

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 arranged 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, it is necessary to perform turning and milling on the outer surface, the inner surface 120 and the outer wall of the flange 110. 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 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. During processing, the inner surface of the spherical shell head 100 and the above-mentioned second area 140 are usually turned by a lathe, and the first area 130 of the spherical shell head 100 is milled by a milling machine.

[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 opening end is parallel to the table surface 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 surface 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 make 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 profile 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 implemented by the following technical solution: 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 clamping 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 on the annular tooling again, 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 tooling on the workbench of the three-axis milling machine, and install the rough-turned spherical shell head on the inclined tooling, so that the axis of the flange on the spherical shell head can be perpendicular to the workbench of the three-axis lathe, and 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 fine 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 tooling 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 tooling on the clamping jaws of the three-axis lathe, use the inner support tooling to clamp the spherical shell head whose inner profile has been finely turned, support the opening of the spherical shell head from the inside through the inner support tooling, and then use the three-axis lathe to finely turn the second area of ​​the outer profile of the spherical shell head;

[0014] Step 8: After finishing the second area, the process step at the open end of the spherical shell head is removed, and the removed part is finish-turned.

[0015] Further, 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] Further, 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 clamping the process step using an annular tooling includes:

[0019] The process steps of the spherical shell head are stacked under the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. The screws are passed through the through holes from below and then screwed into the screw holes. The process steps on the spherical shell head are pressed onto the bottom surface of the circular ring by the screws.

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

[0021] The process steps of the spherical shell head are stacked on top of the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. The screws are passed through the through holes from above and then screwed into the screw holes. The process steps on the spherical shell head are pressed onto the top surface of the circular ring by the screws.

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

[0025] Further, in order to better implement the present invention, in step 3, the method of using a three-axis milling machine to roughly 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 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 rough mill the remaining part of the first area.

[0027] Further, 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] Further, 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] The process steps of the spherical shell head are stacked under the circular ring so that the through holes on the process steps correspond to the screw holes on the circular ring. The screws are passed through the through holes from below and then screwed into the screw holes. The process steps on the spherical shell head are pressed onto the bottom surface of the circular ring by the screws.

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

[0032] In step 7, the method of clamping the spherical shell head by 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 a three-axis lathe and a three-axis milling machine, with lower cost. The motion rigidity of the three-axis lathe is higher than that of 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0037] Figure 1 It is a structural schematic 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 It is a structural schematic diagram of a spherical shell head provided with a process step in an embodiment of the present invention;

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

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

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

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

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

[0045] Fig. 9 It is a schematic structural diagram of the spherical shell head in the embodiment of the present invention when it is processed on an inclined tooling and a three-axis milling machine;

[0046] Fig.10 is a schematic structural diagram of an inner support tooling in an embodiment of the present invention;

[0047] Fig.11 It is a schematic diagram of the installation structure of the spherical shell head on the inner support tooling in an embodiment of the present invention;

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

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

[0050] Fig.14 It is a flow chart of a method for processing a spherical shell head of a spacecraft fuel tank provided by an embodiment of the present invention.

[0051] In the figure:

[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 frame, 420-inclined frame, 421-locking pin hole, 430-support rod, 500-inner support tooling, 510-circular plate, 520-convex ring, 530-pressing block. DETAILED DESCRIPTION

[0053] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to 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 the spacecraft fuel tank, the spherical shell head 100 having an open end, an inner surface 120 and an outer surface, two symmetrical flanges 110 are arranged on the outer surface, and 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 on the outer surface except the first area 130.

[0056] The processing method is as Fig.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 for machining the process step 200 at the open end of the spherical shell head 100 is specifically as follows: using the blank surplus of the blank to machine 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, and 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 in 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 flip 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 a plurality of screws. A plurality of screw holes 310 are provided on the circular ring. The size of the circular ring is adapted to the process step 200 , and the positions of the plurality of screw holes 310 correspond one-to-one to the plurality of through holes 210 .

[0061] In step 2, if Figure 5 As shown, the method of clamping the process step 200 with the annular tooling 300 is specifically to dock the process step 200 of the spherical shell head 100 under the circular ring, so that the multiple through holes 210 on the process step 200 correspond one by one to the multiple screw holes 310 on the circular ring, and then the screws are first 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 clamping the spherical shell head 100 onto the annular tooling 300 again is specifically to stack the process steps 200 of the spherical shell head 100 on top of the circular ring, so that the multiple through holes 210 on the process steps 200 correspond one by one to the multiple 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 in only some of the corresponding screw holes 310 and through holes 210. 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 process step 200 on the spherical shell head 100 is clamped by means of the annular tool 300, and then the annular tool 300 is clamped on the clamping jaws of the three-axis lathe, so that the clamping jaws on the machine tool can avoid direct contact with the spherical shell head 100 and damage to the spherical shell head 100. The setting of the process step 200 can also support the opening of the spherical shell head 100, so that the spherical shell head 100 is 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 tooling 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 onto 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 tooling, 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 tooling, 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, if Figure 7 , Figure 8 as well as Fig. 9 As shown, the oblique tooling 400 in this embodiment includes a locking pin, a base frame 410, an inclined frame 420 and a support rod 430. The installation of the oblique tooling 400 on the workbench of the three-axis milling machine is specifically to install the base frame 410 on the workbench of the three-axis milling machine. The inclined frame 420 is fixedly arranged on the base frame 410. The inclined angle of the inclined frame 420 relative to the base frame 410 is 40°. The support rod 430 is supported between the base frame 410 and the inclined frame 420. The inclined frame 420 has an inclined surface. After installation, the angle between the inclined surface and the workbench of the three-axis milling machine is 40°. It should be noted that the angle between the center axis of the flange 110 on the spherical shell head 100 and the end face of the opening end of the spherical shell head 100 is 50°.

[0067] In step 3, the method of 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 face 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 process step 200 on the spherical shell head 100 is locked on the inclined frame 420 by using the locking pin. It should be noted that the locking pin hole 421 is opened on the inclined surface of the inclined frame 420, and the number of the locking pin holes 421 is also multiple, and the position of the locking pin hole 421 corresponds to the position of the through hole 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°, therefore, 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 meet. Of course, in this step, the three-axis milling machine is used to rough mill the outer wall of the flange 110 and a 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 specifically 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 roughly 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 during the standing process, the internal stress of the spherical shell head 100 can be naturally eliminated.

[0071] Step 5: The spherical shell head 100 with internal stress eliminated is mounted again on the inclined tooling 400 installed on the three-axis milling machine, and the first area 130 of the spherical shell head 100 and the outer wall of the flange 110 are finely milled by the three-axis milling machine. 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 part 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 fine-mill another part 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 part 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 part of the first area 130. In this way, the outer walls of the two flanges 110 and the entire first area 130 are finely milled.

[0073] During the above-mentioned rough milling and fine milling process, the inclined tooling 400 clamps the process step 200 and will not directly contact the spherical shell head 100, thereby further reducing the 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 with the first area 130 finely milled onto the annular tooling 300 installed on the three-axis lathe, so that the opening of the spherical shell head 100 faces upward, and use the three-axis lathe to fine-turn the inner profile 120 of the spherical shell head 100. In this step, the method of clamping the spherical shell head 100 onto the annular tooling 300 is specifically to stack the process step 200 of the spherical shell head 100 below the annular ring, so that the through hole 210 on the process step 200 corresponds to the screw hole 310 on the annular ring, and then screw the screw through the through hole 210 from the bottom and then screw it into the screw hole 310, and use the screw to press the process step 200 on the spherical shell head 100 onto the bottom surface of the annular ring. After this step, the inner profile 120 of the spherical shell head 100 is processed.

[0075] Step 7: Clamp the inner support fixture 500 in the jaws of the three-axis lathe, use the inner support fixture 500 to clamp the spherical shell head 100 whose inner surface 120 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 of the outer surface of the spherical shell head 100.

[0076] After the above-mentioned 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 is likely to be unable 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, if Fig.10 , Fig.11 and Fig.12 As shown, the inner 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 a 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 by using the inner support tool 500 is specifically as follows: the spherical shell head 100 is turned 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. The pressing block 530 can be connected to the circular plate 510 by screws, or it can be connected to an external structure, as long as the process step 200 on the spherical shell head 100 can be pressed by the pressing block 530.

[0079] By supporting the wall of the opening of the spherical shell head 100 with the internal support fixture 500, it is not only possible to ensure that the three-axis lathe can perform fine turning on the second area 140 on the outer surface, but also to effectively reduce the probability of deformation of the spherical shell head 100 during fine turning. Fig.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] By means of the spherical shell head processing method for a 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 can be completed by only 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 larger cutting depth, thereby shortening the turning and milling processing cycle of the spherical shell head 100.

[0082] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope 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, then 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 tooling (300) so that the opening of the spherical shell head (100) faces upward, and use a three-axis lathe to finely turn the inner surface (120); Step 7: Clamp the inner support fixture (500) on the clamping jaws of the three-axis lathe, use the inner support fixture (500) to clamp the finely turned spherical shell head (100), 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 finely turn the second area (140); Step 8: After finishing the second area (140), the process step (200) is removed and the removed portion is finish-turned.

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 of machining a process step (200) at the open end of the spherical shell head (100) comprises: The blank surplus of the blank is used to machine an annular boss surrounding the opening on the outer side wall of the opening end of the spherical shell head (100), and a through hole (210) is opened on the annular boss, and the annular boss constitutes the process step (200).

3. The method for processing 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, and a screw hole (310) is provided on the circular ring; In the step 2, the method of clamping the process step (200) by using the annular tool (300) includes: The process step (200) is stacked under 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 processing the spherical shell head of a spacecraft fuel tank according to claim 3, characterized in that: In step 2, the method of clamping the spherical shell head (100) onto the annular tooling (300) again comprises: The process step (200) is stacked on top of the circular ring so that the through hole (210) corresponds to the screw hole (310), a 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 circular ring by the screw.

5. The method for processing 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 being mounted 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 oblique tooling (400) comprises: 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), and 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), and the process step (200) is locked on the tilting frame (420) by using the locking pin.

6. The method for processing the spherical shell head of a spacecraft fuel tank according to claim 5, characterized in that: In step 3, the method of roughly milling the first region (130) and the flange (110) using a three-axis milling machine comprises: 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 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 processing 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 region (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 fine-mill another portion of the first region (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 region (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 region (130).

8. The method for processing 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 tooling (300) comprises: The process step (200) is stacked under 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 processing the spherical shell head of a spacecraft fuel tank according to claim 2, characterized in that: The inner support tool (500) comprises a circular plate (510), a convex ring (520) and a pressing block (530), wherein the convex ring (520) is fixedly arranged on a side plate surface of the circular plate (510), and the convex ring (520) is coaxially arranged with the circular plate (510), and the pressing block (530) is installed 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 inverted 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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