A conical bellows spinning forming tool

Abstract

The utility model relates to a kind of conical bellows spinning forming tool, including the forming section die or conical bellows die clamped by three-jaw chuck, conical bellows die includes base mould in the shape of cone, several embedded slots are provided along the length direction of base mould and several telescopic bellows assemblies are coaxially embedded in embedded slot, telescopic bellows assembly includes lower panel fixed in embedded slot, several sliding grooves are uniformly distributed on the upper surface of lower panel along its peripheral portion, sliding block is slidably connected in sliding groove, and push plate is fixed on the sliding block by connecting rod, arc-shaped bellows module is fixed on the outer end of push plate, bushing is arranged on the top of connecting rod and is slidably connected on upper panel by bushing, arc-shaped guide arc groove is correspondingly provided on upper panel, core shaft is arranged in the center of base mould and upper panel is rotated by core shaft driving;Forming section die or conical bellows die is provided with spinning wheel for spinning, and the conical bellows spinning forming tool is low in processing cost, and the disassembly of bellows and core mould is facilitated.

Description

Technical Field

[0001] This utility model relates to a tooling for spinning a tapered corrugated tube. Background Technology

[0002] A tapered corrugated pipe is a flexible pipe fitting with a diameter that gradually changes along the axial direction and periodically undulating annular corrugations on its wall. The tapered structure disperses concentrated stress, reducing the risk of localized deformation or cracking. Furthermore, tapered corrugated pipes are less prone to buckling under pressure, exhibiting high stability. Combining the flexibility of corrugated pipes with the characteristics of a tapered structure, tapered corrugated pipes enable more precise displacement and force transmission, offering advantages in applications requiring large displacement compensation, high sealing, and high stability. In addition, the tapered structure allows for seamless connection of pipes or equipment of different diameters, reducing the need for additional adapters and simplifying the installation process. Due to its excellent properties, tapered corrugated pipes have great application potential in aerospace, machinery, civil engineering, and many other fields.

[0003] Due to the asymmetry of its geometry, tapered bellows are significantly more difficult to form than cylindrical bellows, and there are few mature forming methods. Currently, bellows are mostly manufactured using either split welding or hydroforming. The first method is hydroforming. Hydroforming tapered bellows offers advantages such as high precision, good surface quality, and the ability to form complex irregular structures. However, hydroforming is not flexible enough, requiring specialized hydraulic presses and precision molds, making small-batch production uneconomical. Precise control of pressure at different locations is necessary during the forming process to avoid uneven stress on the conical surface. Mold debugging and single-piece forming are time-consuming, making the forming process challenging. The second method is split welding. Split-welded tapered bellows suffer from low weld strength, stress concentration in the weld area, and a tendency to fatigue cracking.

[0004] Spin-formed corrugated pipes offer significant advantages in terms of high production efficiency and low cost, making them particularly suitable for mass production. This process, using a spinning wheel for continuous forming, not only boasts highly versatile equipment and convenient mold replacement, but also allows for rapid adaptation to different product specifications. While the precision is slightly lower, it meets the requirements of applications such as automotive exhaust pipes and general industrial pipelines where high precision is not necessary, offering excellent cost-effectiveness and advantages for large-scale production. However, forming tapered corrugated pipes is more difficult than forming ordinary cylindrical corrugated pipes. Specifically, the necking ratio varies at different locations during the forming process, easily leading to uneven wall thickness or cracking. Furthermore, the corrugated shape of the pipe makes it easy for the mandrel to get stuck inside the formed pipe, resulting in difficulties in mandrel demolding. Utility Model Content

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a tooling for spinning tapered corrugated pipes, which is not only reasonable in structure, but also reduces costs.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: a conical corrugated tube spinning forming tooling, including a forming section mold or a conical corrugated tube mold clamped by a three-jaw chuck. The conical corrugated tube mold includes a conical base mold. The base mold has several slots spaced apart along its length, and several telescopic corrugated components are coaxially embedded in the slots. The telescopic corrugated components include a lower panel fixed in the slot. The upper surface of the lower panel has several radially extending grooves evenly distributed along its periphery. A slider slides in the grooves, and a push plate is fixed to each slider via a connecting rod. The outer end of each push plate is fixed with an arc-shaped corrugated module to facilitate the pushing of the tube blank. A bushing is provided at the top of the connecting rod and slides through the bushing on an upper panel above the lower panel. The upper panel has corresponding arc-shaped guide arc grooves for the bushing to slide and coordinate the extension and retraction of the slider. A mandrel passes through the center of the base mold and drives the upper panel to rotate via the mandrel. A spinning wheel for spinning is provided outside the forming section mold or the conical corrugated tube mold.

[0007] Furthermore, the spindle is rotatably connected to the lower panel via a bearing.

[0008] Furthermore, both the upper and lower panels are evenly distributed with a number of pin holes in a ring. The base mold has insertion holes that correspond one-to-one with the pin holes, with the smaller end of the diameter facing inward. The pin holes on the upper and lower panels are staggered so that after the corrugated module is rotated out, the pin holes on the upper and lower panels overlap and are inserted into the pin holes for positioning by the positioning pins passing through the insertion holes from the outside to the inside.

[0009] Furthermore, the expansion and contraction ranges of the expansion and contraction components are not uniform. As the diameter of the base mold decreases, the expansion and contraction range of the expansion and contraction components gradually decreases to ensure the protrusion range of each corrugated module.

[0010] Furthermore, the forming section mold includes a conical forming mold, the large end of which is fixed by a fixed mold base.

[0011] Furthermore, the small end of the base mold or forming mold is coaxially connected to a positioning block, and a tail pin is coaxially connected to the outside of the positioning block, with the tail pin end of the tail pin being connected to the center of the positioning block.

[0012] Furthermore, the three-jaw chuck is fixed to the flange away from the clamping end.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1) This design solves the problem of high costs associated with the first method (hydraulic forming), which requires specialized hydraulic presses and precision molds. The tooling is designed with segmented molds, allowing for real-time disassembly and replacement of the processing sections based on the designed parts. Furthermore, the mold bears relatively low forces during spinning, requiring lower mechanical properties of the mold material. In small-batch production, the mold can be made of PLA using 3D printing, further reducing costs.

[0015] 2) This method solves the problems of low production efficiency and low weld strength inherent in the second type of method (split welding). The spinning forming process of the conical corrugated pipe is a one-piece forming process, and the formed part does not require welding. This process uses a spinning wheel for continuous forming, which not only makes the equipment highly versatile and efficient, and easy to change molds, allowing for rapid adaptation to the processing of products of different specifications, but also makes the processing simple to operate, low in processing cost, and easy to automate.

[0016] 3) This tooling solves the problem of difficult forming of tapered corrugated pipes due to different necking ratios at different locations. First, the tapered pipe is prepared using a forming section mold, ensuring the same reduction amount at all locations during the tapered corrugated pipe processing. Then, the forming section mold is replaced with a tapered corrugated pipe mold to process the tapered corrugated pipe.

[0017] 4) A stretchable corrugated structure was designed, which solved the problem that the core mold could not be removed after spinning due to the corrugated tube waveform structure.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the tapered tube spinning forming tool and forming process in an embodiment of this utility model;

[0020] Figure 2 This is a schematic diagram of the conical corrugated pipe spinning forming tooling and forming process in an embodiment of this utility model;

[0021] Figure 3 This is a schematic diagram of the structure of the telescopic corrugated component in an embodiment of this utility model;

[0022] Figure 4 This is a schematic diagram of the conical corrugated pipe mold during shrinkage in an embodiment of this utility model;

[0023] Figure 5 This is a schematic diagram of the conical corrugated pipe mold during stretching in an embodiment of this utility model;

[0024] Figure 6 This is a schematic diagram of the conical corrugated pipe structure obtained after forming in an embodiment of this utility model.

[0025] In the diagram: 1. Flange, 2. Three-jaw chuck, 3. Fixed mold base, 4. Tube blank, 5. Forming section mold, 6. Rotary wheel, 7. Mandrel, 8. Positioning block, 9. Tail top ejector rod, 10. Tail top, 11. Corrugated module, 12. Upper panel, 13. Double convex bearing, 14. Bushing, 15. Connecting rod, 16. Slider, 17. Push plate, 18. Lower panel, 19. Positioning pin, 20. Base mold, 21. Conical corrugated pipe mold, 22. Insert groove, 23. Slide groove, 24. Guide arc groove, 25. Pin hole, 26. Insertion hole, 27. Forming mold. Detailed Implementation

[0026] To make the above-mentioned features and advantages of this utility model more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation.

[0027] like Figures 1-6 As shown, a conical corrugated tube spinning forming fixture includes a forming section mold 5 or a conical corrugated tube mold 21 clamped by a three-jaw chuck 2. The conical corrugated tube mold includes a conical base mold 20. The base mold has several slots 22 spaced apart along its length, and several telescopic corrugated components are coaxially embedded in the slots. The telescopic corrugated components include a lower panel 18 fixed in the slot. The upper surface of the lower panel has five sets of radially extending slide grooves 23 evenly distributed around its periphery. A slider 16 slides in the slide groove, and a push plate 17 is fixedly connected to each slider via a connecting rod 15. The bottom of the connecting rod is fixedly connected to the push plate and the slider. The push plate extends... The direction is consistent with the extension direction of the chute. The outer ends of the push plates are all fixed with a corrugated module 11 that is arc-shaped to facilitate the top of the tube blank 4. The cross-section of the corrugated module is semi-circular and the whole is arc-shaped so that the head and tail are connected in a ring shape when shrinking. The top of the connecting rod is provided with a bushing 14 and slides on the upper plate above the lower plate through the bushing. The upper plate is parallel and coaxially arranged above the lower plate. The upper plate is provided with a corresponding arc-shaped guide arc groove 24 for the bushing to slide and link the slider extension and retraction. The center of the base mold is provided with a mandrel and drives the upper plate to rotate through the mandrel. The forming section mold or the conical corrugated tube mold is provided with a spinning wheel 6 for spinning.

[0028] In this embodiment of the invention, the mandrel is rotatably connected to the lower panel via a double cam bearing 13.

[0029] In this embodiment of the utility model, a plurality of pin holes 25 are evenly distributed in a ring on both the upper panel and the lower panel. The base mold has insertion holes 26 corresponding to the pin holes one by one, with the smaller diameter end facing inward. The pin holes on the upper panel and the lower panel are staggered so that after the corrugated module is rotated out, the pin holes on the upper panel and the lower panel overlap and are inserted into the pin holes for positioning by the positioning pins 19 passing through the insertion holes from the outside to the inside.

[0030] In this embodiment of the invention, the telescopic corrugated components have different telescopic ranges. As the diameter of the base mold decreases, the telescopic corrugated components gradually reduce their telescopic range to ensure the protrusion range of each corrugated module.

[0031] In this embodiment of the utility model, the forming section mold includes a conical forming mold 27, the large end of which is fixed by a fixed mold base, and a mandrel is also coaxially inserted inside the forming mold to facilitate fixation.

[0032] In this embodiment of the utility model, the small end of the base mold or the forming mold is coaxially connected to a positioning block 8, and a tail top 10 is coaxially connected to the outside of the positioning block. The end of the tail top pin 9 of the tail top is connected to the center of the positioning block.

[0033] In this embodiment of the utility model, the three-jaw chuck is fixed to the flange 1 away from the clamping end.

[0034] In this embodiment of the utility model, in order to ensure that the bushing 14, the connecting rod 15 and the slider 16 connected thereto slide linearly along the lower panel 18, the equidistant arc design of the arc-shaped groove of the upper panel 12 must satisfy the following formula:

[0035]

[0036] In the formula: a is the minimum distance between the center of the circle and the equidistant line; vt is the size of the expandable distance; mt is the radian that can be rotated; t is the rotation time.

[0037] In this embodiment of the invention, the tooling first assembles the forming section mold, inserts the initial tube blank into the forming section mold, clamps the tube blank and mold with a three-jaw chuck to ensure synchronous rotation, applies force to the tail end to prevent the tube blank from shifting, and applies pressure to the tube blank using a spinning wheel to form a tapered tube. After forming, the tail end is removed, the tube is taken out, and the forming section mold in the segmented mold is replaced with a tapered corrugated tube mold. After inserting the tapered tube into the mold, the mandrel is rotated counterclockwise to extend the corrugated structure in the mold. The subsequent operations of forming the tapered tube are repeated to form the desired tapered corrugated tube shape during the plastic deformation process. After forming, the mandrel is rotated clockwise to shrink the corrugated structure in the mold, the tapered corrugated tube mold is taken out, and then the fixed mold base is taken out, finally obtaining the tapered corrugated tube. The principle and method of the spinning wheel are common settings and will not be elaborated on here.

[0038] Working principle of this utility model embodiment:

[0039] Step 1: First, insert and fix the mandrel and connect the fixed mold base 3 with the forming section mold 5 to complete the assembly of the tapered tube segment mold.

[0040] Step 2: Install the segmented mold clamping on the three-jaw chuck 2, control the tail tip 10 to move forward to provide axial support, and determine the positions of the left and right rotating wheels so that the two rotating wheels are on the same plane;

[0041] Step 3: Control the tail 10 to move backward, remove the forming section mold, apply lubricating oil to the surface of the core mold, put the tube blank 4 into the forming section mold, clamp it on the mounting three-jaw chuck 2, control the tail 10 to move forward to provide axial support, and apply lubricating oil to the surface of the tube blank 4.

[0042] Step 4: Turn on the spinning wheel switch. The spinning wheel 6 will start spinning along the spinning path. During the spinning process, lubricating oil will be continuously applied to the surface of the blank to reduce friction and cool the blank.

[0043] Step 5: After forming, control the tail jack 10 to retract, release the three-jaw chuck 2 to remove the part. Pull out the tapered tube segment mold to obtain the desired tapered tube.

[0044] Step 6: Replace the forming section mold 5 with the assembled conical corrugated pipe mold, rotate the mandrel 7 counterclockwise to the limit position, open the corrugated module, and insert the positioning pin. Repeat steps 2 to 4.

[0045] Step 7: After the conical corrugated tube is formed, control the tail jack 10 to retract, release the three-jaw chuck 2, and remove the part. Pull out the positioning pin 19 inside the conical corrugated tube mold, rotate the mandrel clockwise to the limit position, shrink the waveform structure, and pull out the conical corrugated tube mold to obtain the required conical corrugated tube.

[0046] This utility model is not limited to the preferred embodiment described above. Anyone can derive other forms of tapered corrugated tube spinning forming tooling based on the teachings of this utility model. All equivalent variations and modifications made within the scope of the claims of this utility model should be considered within the scope of this utility model.

Claims

1. A tooling for spinning a tapered corrugated tube, characterized in that: The system includes a forming section mold or a conical corrugated pipe mold clamped by a three-jaw chuck. The conical corrugated pipe mold includes a conical base mold. The base mold has several slots spaced apart along its length, and several telescopic corrugated components are coaxially embedded in the slots. Each telescopic corrugated component includes a lower panel fixed in the slot. The upper surface of the lower panel has several radially extending grooves evenly distributed around its periphery. A slider slides in the grooves, and a push plate is fixed to each slider via a connecting rod. The outer end of each push plate is fixed with an arc-shaped corrugated module to facilitate the ejection of the pipe blank. A bushing is provided at the top of the connecting rod and slides through the bushing onto an upper panel above the lower panel. The upper panel has corresponding arc-shaped guide grooves for the bushing to slide and coordinate with the slider's extension and retraction. A mandrel passes through the center of the base mold and drives the upper panel to rotate via the mandrel. A spinning wheel for spin forming is provided outside the forming section mold or the conical corrugated pipe mold.

2. The conical corrugated tube spinning forming tooling according to claim 1, characterized in that: The spindle is rotatably connected to the lower panel via a bearing.

3. The conical corrugated tube spinning forming tooling according to claim 1, characterized in that: Both the upper and lower panels have a number of pin holes evenly distributed in a ring. The small end of the base mold has an insertion hole that corresponds to each pin hole. The pin holes on the upper and lower panels are staggered so that after the corrugated module is rotated out, the pin holes overlap and are inserted into the pin holes for positioning by the positioning pins passing through the insertion holes from the outside to the inside.

4. The conical corrugated tube spinning forming tooling according to claim 1, characterized in that: The expansion and contraction ranges of the expansion and contraction components are not consistent, and the expansion and contraction range of the expansion and contraction components gradually decreases as the diameter of the base mold decreases.

5. The conical corrugated tube spinning forming tooling according to claim 1, characterized in that: The forming section mold includes a conical forming mold, the large end of which is fixed by a fixed mold base.

6. The conical corrugated tube spinning forming tooling according to claim 5, characterized in that: The base mold or forming mold is coaxially connected to a positioning block at its small end. A tail pin is coaxially connected to the outside of the positioning block, and the end of the tail pin is connected to the center of the positioning block.

7. The conical corrugated tube spinning forming tooling according to claim 1, characterized in that: The three-jaw chuck is fixed to the flange away from the clamping end.

Images