A precision auxiliary clamping system and method for combustion chamber shells with large length-to-diameter ratios.

Abstract

This invention relates to a precision auxiliary clamping system and method for combustion chamber shells with large length-to-diameter ratios, particularly suitable for high-energy beam welding clamping of ultra-long workpieces such as rocket engine shells. The auxiliary clamping system consists of four main modules: a metal guide rail, a movable support plate, a tail top, and an adjusting handwheel. The metal guide rail is fixed to the existing processing platform as a basic extension; the movable support plate is slidably mounted on the metal guide rail for large-stroke coarse adjustment; the tail top is connected to a linear guide rail on the movable support plate via a slider at its bottom, and is precisely positioned using a screw-nut structure driven by the adjusting handwheel, ultimately supporting the shell by tightening the tail top tip against the center hole. Based on this system, the clamping method includes steps such as platform expansion, support plate coarse adjustment, tail top fine adjustment, and locking. This invention, through modular design and a sliding guide structure, effectively expands the clamping range of existing tooling, significantly improves clamping efficiency and positioning accuracy, and ensures welding quality.

Description

Technical Field

[0001] This invention relates to the field of tooling technology in mechanical manufacturing, and specifically to a precision auxiliary clamping system and method for combustion chamber shells with large length-to-diameter ratios. Background Technology

[0002] Thin-walled shell structures with high aspect ratios are core load-bearing components of aerospace launch vehicle engines. These components typically utilize high-strength, lightweight alloy materials and are joined into a single unit using high-energy beam welding technologies such as electron beam welding. During welding, the workpiece is usually driven to rotate by a three-jaw chuck on a machine tool spindle, while the tail end of the workpiece must be constrained by a tail-end device that provides precise centering support. However, as aerospace products become larger and lighter, the aspect ratio of the shell continues to increase, posing new challenges to existing clamping technologies.

[0003] First, due to the inherent dimensions of existing machining platforms, their effective clamping length often cannot meet the needs of ultra-long shells. Second, traditional tailstock devices are typically fixed directly to the positioning holes of the worktable with bolts, making position adjustment extremely inconvenient. When machining shells of different lengths, operators need to unload the heavy tailstock assembly, move it to its approximate position, and then realign and fix it. This process is not only inefficient but also makes it difficult to ensure precise alignment between the tailstock's tip and the machine tool spindle's rotation center. Any slight coaxiality deviation will introduce additional radial runout during high-speed welding, which may affect weld quality or even damage the workpiece.

[0004] Therefore, there is a need in the field for a dedicated auxiliary clamping system and method that can effectively expand the clamping range of existing platforms and enable rapid, precise, and flexible adjustment of the tail-top device, in order to overcome the shortcomings of the prior art and meet the needs of high-quality and high-efficiency welding production of large aspect ratio shell structures. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to overcome the technical deficiencies of existing technologies, such as insufficient effective length of the machining platform, cumbersome adjustment of the tail top device position, and difficulty in guaranteeing centering accuracy. It provides a precision auxiliary clamping system and method for combustion chamber shells with large length-to-diameter ratios, effectively expanding the working range of the original machining platform, realizing rapid positioning of the tail top device through rough and fine machining, ensuring high-precision centering with the spindle, and providing a stable tooling foundation for high-quality welding.

[0006] To achieve the above objectives, the specific technical solution of the present invention is as follows: A precision auxiliary clamping system for combustion chamber shells with high length-to-diameter ratios includes: A metal guide rail, fixed to the processing platform, provides basic support and sliding guidance for the moving pallet; A movable tray, which is slidably mounted on a metal guide rail, supports the tail top and allows for position adjustment; Tail top, which is mounted on a movable support plate and presses against the center hole of the tooling at the tail end of the housing to achieve positioning and support; An adjusting wheel, which is used to drive the tail fin to make precise displacement; The movable pallet includes a pallet base, linear guide rails, a transmission screw, and a transmission support. The pallet base has a frame structure, with its bottom slidably connected to the metal guide rails and linear guide rails fixedly installed on both sides of its top. Multiple positioning holes are spaced apart along the length of the linear guide rails. The transmission support is fixed to the end of the pallet base, and the transmission screw is rotatably supported on the transmission support through bearings and connected to the adjusting wheel. The tail top includes a tip body, a sleeve, a tail seat body, a tail top base, a clamping bolt, a slider, and a nut. The front end of the tip body is used to mate with the center hole of the tooling at the tail end of the housing, and the tail end is connected to the sleeve. By driving the sleeve, the tip body can be moved to extend and retract along its axial direction. The sleeve is located outside the tip body and is slidably engaged with the tail seat body through a dovetail groove structure. The tail seat body is fixed on the tail top base and has a bearing installed inside. A slider that mates with a linear guide rail is installed at the bottom of the tail top base, allowing the tail top to slide along the linear guide rail. A nut that mates with the thread of the transmission screw is fixed at the center of the lower part of the tail top base, and the clamping bolt is inserted into the positioning hole on the linear guide rail to limit the fixed position of the tail top base.

[0007] Preferably, the movable pallet further includes a reinforcing rib and a limit positioning bolt. The reinforcing rib is fixed above the transmission support; the limit positioning bolt is installed on the reinforcing rib, with its end extending into the sliding area of ​​the linear guide rail, to limit the movement limit position of the tail top and prevent slippage.

[0008] Preferably, the movable pallet further includes limiting blocks, an even number of which are respectively disposed on both sides of the top of the pallet base. The limiting blocks are engaged with the sides of the pallet base by fasteners to limit the lateral movement and force deviation of the linear guide rail.

[0009] Preferably, the pallet base is a frame structure welded from metal profiles, with multiple reinforcing ribs inside; the bottom surface of the pallet base is machined with multiple threaded holes for installing adjustable limit blocks.

[0010] Preferably, the movable pallet can slide along the metal guide rail and extend beyond the end of the metal guide rail to accommodate the clamping of extra-long workpieces.

[0011] Preferably, the transmission screw has a precision grade of C7, a pitch of 2-10mm, and both ends of the screw are positioned with the inner ring of the roller bearing through the shaft shoulder. The outer ring of the bearing is interference-fitted with the circular hole of the transmission support.

[0012] Preferably, the adjusting wheel is driven manually or electrically.

[0013] A precision auxiliary clamping method for combustion chamber shells with high length-to-diameter ratios includes the following steps: During installation and commissioning, the metal guide rail is fixed to the surface of the processing platform with bolts, and its guiding direction is aligned with the axis of the three-jaw chuck, so that the coaxiality error between the two is no more than 0.05mm. Coarse and fine positioning: Adjust the relative position of the moving pallet on the metal guide rail according to the length of the housing to be clamped to achieve coarse positioning of the tail top; rotate the adjusting wheel to drive the transmission screw to rotate, which in turn drives the tail top base to slide along the linear guide rail of the moving pallet via its bottom slider. When it slides to the approximate target position, insert the clamping bolt into the nearest positioning hole on the linear guide rail to fix the longitudinal position of the tail top base. The shell positioning support clamps one end of the shell to be welded onto the external positioning chuck and fixes it in place. The sleeve at the tail top moves, causing the tip body to extend and retract along its axis, so that the front end of the tip body extends into the center hole of the tooling at the tail end of the shell, thereby achieving the positioning and support of the shell. The tail top is locked, and the sleeve of the tail top is locked to complete the axial positioning of the center body, thereby achieving stable support for the shell workpiece throughout the entire processing.

[0014] The beneficial effects of this invention are as follows: It effectively expands the processing range by combining metal guide rails and a movable pallet, thus extending the clamping length of the original processing platform and solving the problem of clamping and positioning ultra-long housings; it achieves rapid and accurate positioning by employing a graded positioning strategy of "coarse adjustment with movable pallet + fine adjustment with lead screw driving the tailstock," combined with mechanical locking of positioning holes, ensuring both adjustment efficiency and precise positioning of the tailstock; it ensures high-precision alignment by using a precision guide rail slider system and a strict installation and calibration process to guarantee the high coaxiality requirement between the tailstock and the spindle; and it enhances safety and reliability by strengthening multiple safety designs such as ribs, limit positioning bolts, and adjustable limit blocks, effectively preventing safety hazards such as component slippage and overtravel, and enhancing system rigidity. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the clamping system described in this invention; Figure 2 This is a top view of the clamping system described in this invention; Figure 3 This is a cross-sectional view of the clamping system described in this invention; Figure 4 This is a front view of the clamping system described in this invention; Among them, 1 is a metal guide rail, 2 is a movable pallet, 3 is the tail top, 4 is an adjusting handwheel, 210 is the pallet base, 220 is a linear guide rail, 230 is a transmission support, 240 is a reinforcing rib, 250 is a limit positioning bolt, 260 is a transmission screw, 270 is a limit block, 310 is the center body, 320 is a sleeve, 330 is the tail seat body, 340 is the tail top base, 350 is a clamping bolt, 360 is a slider, and 370 is a countersunk screw. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.

[0017] refer to Figures 1 to 4 This embodiment provides a specific implementation of a precision auxiliary clamping system for combustion chamber shells with large length-to-diameter ratios. The auxiliary clamping system consists of four main modules: a metal guide rail 1, a movable pallet 2, a tail top 3, and an adjusting handwheel 4.

[0018] The metal guide rail 1 is made of high-strength alloy steel and precision ground, with a length of 1500mm. Its bottom surface is firmly fixed to the worktable of the original electron beam welding machine by multiple sets of internal hexagon bolts. During installation, a high-precision level and dial indicator are used for alignment to ensure that the guide plane of the metal guide rail 1 is strictly parallel to the rotation axis of the three-jaw chuck on the welding machine spindle.

[0019] The movable pallet 2 is placed entirely on the metal guide rail 1. The core component of the movable pallet 2 is the pallet base 210, which is a frame structure welded from standard aluminum alloy profiles with multiple internal reinforcing ribs, combining lightweight and high rigidity. Two high-precision linear guide rails 220 are fixedly installed on both sides of the top of the pallet base 210. A positioning hole is opened on the linear guide rail 220 at 200mm intervals. Transmission supports 230 are provided at both ends of the long axis of the pallet base 210, and triangular reinforcing ribs 240 are fixed above the transmission supports 230 to enhance support rigidity. A C7 precision lead screw 260 with a 2mm pitch is rotatably supported on the transmission support 230 via roller bearings at both ends. Limit positioning bolts 250 are screwed into the reinforcing ribs 240 for safety protection.

[0020] The tail top 3 is mounted on the linear guide rail 220 of the movable support plate 2 via a tail top base 340 at its bottom. The tail top base 340 is a box-shaped structure welded from steel plates. Four sliders 360 are mounted on both sides of its bottom via countersunk screws 370. These sliders 360 form a sliding pair with the linear guide rail 220. A nut is fixedly installed at the center of the bottom of the tail top base 340. This nut forms a precision screw-nut transmission pair with the aforementioned transmission screw 260. The tail top base 340 is also provided with a clamping bolt 350. When it slides to the approximate target position, the clamping bolt 350 can be inserted into the nearest positioning hole on the linear guide rail 220 to achieve coarse positioning and locking of the tail top 3. A tail seat body 330 is fixed above the tail top base 340. The rear end of the tip body 310 is connected to the sleeve 320, and the whole body passes through the front end of the tail seat body 330. The outer side of the sleeve 320 and the inner hole of the tailstock 330 are fitted with a dovetail groove structure, which allows the top body 310 to be slightly contracted axially by rotating the sleeve 320 to adapt to the fine adjustment of the tightening force.

[0021] The adjusting handwheel 4 is connected to the shaft end of the transmission screw 260 via a spline in its inner hole. Turning the handwheel clockwise or counterclockwise will drive the transmission screw 260 to rotate, thereby causing the tailstock 3 to move precisely in a straight line along the linear guide rail 220.

[0022] The method for clamping a housing using the clamping system described in this embodiment includes the following steps: During installation and debugging, the metal guide rail 1 is fixed to the surface of the original processing platform with bolts. The guide rail is precisely adjusted using measuring instruments to ensure that its guiding direction is aligned with the axis of the three-jaw chuck, and that the coaxiality error between the two is no more than 0.05mm. Coarse and fine positioning: Adjust the relative position of the moving pallet 2 on the metal guide rail 1 according to the length of the shell to be clamped to achieve coarse positioning of the tail top 3; rotate the adjusting wheel 4, drive the transmission screw 260 to rotate, and drive the tail top base 340 to slide along the linear guide rail 220 of the moving pallet 2 through its bottom slider 360. When it slides to the approximate target position, insert the clamping bolt 350 into the nearest positioning hole on the linear guide rail 220 to fix the longitudinal position of the tail top base 340. The shell positioning support clamps one end of the shell to be welded onto the external positioning chuck and fixes it in place. The sleeve 320 of the tail top 3 is moved, which drives the top body 310 to extend and retract along its axis, so that the front end of the top body 310 extends into the center hole of the tooling on the rear side of the shell, thereby achieving the positioning and support of the shell. The tail top is locked, and the sleeve 320 of the tail top 3 is locked, thus completing the axial positioning of the top body 310, thereby achieving stable support for the shell workpiece throughout the entire processing process.

[0023] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, based on the concept of the present invention, there will be changes in specific implementation methods and application scope. The content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

[0024] The parts of this invention not described in detail are common knowledge to those skilled in the art.

Claims

1. A precision auxiliary clamping system for combustion chamber shells with large length-to-diameter ratios, characterized in that, include: A metal guide rail, fixed to the processing platform, provides basic support and sliding guidance for the moving pallet; A movable tray, which is slidably mounted on a metal guide rail, supports the tail top and allows for position adjustment; Tail top, which is mounted on a movable support plate and presses against the center hole of the tooling at the tail end of the housing to achieve positioning and support; An adjusting wheel, which is used to drive the tail fin to make precise displacement; The movable pallet includes a pallet base, linear guide rails, a transmission screw, and a transmission support. The pallet base has a frame structure, with its bottom slidably connected to the metal guide rails and linear guide rails fixedly installed on both sides of its top. Multiple positioning holes are spaced apart along the length of the linear guide rails. The transmission support is fixed to the end of the pallet base, and the transmission screw is rotatably supported on the transmission support through bearings and connected to the adjusting wheel. The tail top includes a tip body, a sleeve, a tail seat body, a tail top base, a clamping bolt, a slider, and a nut. The front end of the tip body is used to mate with the center hole of the tooling at the tail end of the housing, and the tail end is connected to the sleeve. By driving the sleeve, the tip body can be moved to extend and retract along its axial direction. The sleeve is located outside the tip body and is slidably engaged with the tail seat body through a dovetail groove structure. The tail seat body is fixed on the tail top base and has a bearing installed inside. A slider that mates with a linear guide rail is installed at the bottom of the tail top base, allowing the tail top to slide along the linear guide rail. A nut that mates with the thread of the transmission screw is fixed at the center of the lower part of the tail top base, and the clamping bolt is inserted into the positioning hole on the linear guide rail to limit the fixed position of the tail top base.

2. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio as described in claim 1, characterized in that, The movable pallet also includes a reinforcing rib and a limit positioning bolt. The reinforcing rib is fixed above the transmission support; the limit positioning bolt is installed on the reinforcing rib, and its end extends into the sliding area of ​​the linear guide rail to limit the movement limit position of the tail top and prevent slippage.

3. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio, as described in claim 1 or 2, is characterized in that... The movable pallet also includes a limiting block, which is an even number and is respectively set on both sides of the top of the pallet base. The limiting block is engaged with the side of the pallet base by fasteners to limit the lateral movement and force deviation of the linear guide rail.

4. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio as described in claim 3, characterized in that, The pallet base is a frame structure welded from metal profiles, with multiple reinforcing ribs inside; the bottom surface of the pallet base is machined with multiple threaded holes for installing adjustable limit blocks.

5. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio as described in claim 1, characterized in that, The movable pallet can slide along the metal guide rail and extend beyond the end of the metal guide rail to accommodate the clamping of extra-long workpieces.

6. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio as described in claim 1, characterized in that, The transmission screw has a precision grade of C7 and a pitch of 2-10mm. The two ends of the screw are positioned with the inner ring of the roller bearing through the shaft shoulder, and the outer ring of the bearing is interference-fitted with the circular hole of the transmission support.

7. A precision auxiliary clamping system for a combustion chamber shell with a large length-to-diameter ratio as described in claim 1, characterized in that, The adjusting wheel can be driven manually or electrically.

8. A precision auxiliary clamping method for combustion chamber shells with large length-to-diameter ratios, characterized in that, Includes the following steps: During installation and commissioning, the metal guide rail is fixed to the surface of the processing platform with bolts, and its guiding direction is aligned with the axis of the three-jaw chuck, so that the coaxiality error between the two is no more than 0.05mm. Coarse and fine positioning: Adjust the relative position of the moving pallet on the metal guide rail according to the length of the housing to be clamped to achieve coarse positioning of the tail top; rotate the adjusting wheel to drive the transmission screw to rotate, which in turn drives the tail top base to slide along the linear guide rail of the moving pallet via its bottom slider. When it slides to the approximate target position, insert the clamping bolt into the nearest positioning hole on the linear guide rail to fix the longitudinal position of the tail top base. The shell positioning support clamps one end of the shell to be welded onto the external positioning chuck and fixes it in place. The sleeve at the tail top moves, causing the tip body to extend and retract along its axis, so that the front end of the tip body extends into the center hole of the tooling at the tail end of the shell, thereby achieving the positioning and support of the shell. The tail top is locked, and the sleeve of the tail top is locked to complete the axial positioning of the center body, thereby achieving stable support for the shell workpiece throughout the entire processing.

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