CN114289574A - Internal low-pressure bending forming device and method for double-layer twisted pipe - Google Patents
Internal low-pressure bending forming device and method for double-layer twisted pipe Download PDFInfo
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- CN114289574A CN114289574A CN202210010581.1A CN202210010581A CN114289574A CN 114289574 A CN114289574 A CN 114289574A CN 202210010581 A CN202210010581 A CN 202210010581A CN 114289574 A CN114289574 A CN 114289574A
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Abstract
The invention discloses an internal low-pressure bending forming device for a double-layer twisted pipe, which is used for bending and forming the double-layer pipe body. According to the invention, the sealing elements are fixed at two ends of the double-layer pipe body and form the closed cavity by enclosing with the gap between the outer pipe and the inner pipe, the cutting of the plug part is not needed, the material utilization rate is improved, the cost is saved, meanwhile, the inner pipe is limited by the core ball before the bending, the liquid medium is filled in the closed cavity, the inner pipe and the outer pipe can be prevented from wrinkling in the pipe winding process, and the forming quality and efficiency are improved.
Description
Technical Field
The invention relates to the technical field of bending equipment, in particular to an internal low-pressure bending forming device and method for a double-layer twisted pipe.
Background
With the development of the automobile industry, the aim of light weight is increasingly pursued, the hollow section twisted tube is increasingly used on parts of each part of an automobile, and the pipe fitting related to the automobile engine generally has the requirement of sound insulation. Generally, a combination of one section of double-layer straight pipe and a plurality of sections of twisted pipes is adopted, sound-insulation filler is filled in the middle of the double-layer straight pipe to reduce noise, and the filler not only increases the weight, but also increases the assembly trouble. Thus again creating a new structure, a double layer twisted tube (as shown in figure 8). The double-layer twisted pipe does not need to be stuffed with sound insulation fillers, and the space between the double-layer twisted pipes is a sound insulation area. This structure is lighter than present structure. However, the forming of the structure is difficult, the existing bending process can only form a single-layer structure, and the prior art also fills fine-particle solid media such as sand and the like in the middle of the gap of the double-layer pipe, then welds an end cover at the double-layer gap at the two end openings of the pipe blank, so that the double-layer pipe becomes a single-layer pipe, is formed by the bending process, and finally cuts off the end cover to pour out the media to obtain the required double-layer pipe.
The bending process is a method for obtaining a section of twisted pipe with regular shape by using a bending die to make a pipe blank move around a certain central line in an arc with a certain fixed radius on a specific bending device, the prior art is as follows, referring to fig. 1 and 2, a core rod A is fixed on a full-automatic pipe bender, core balls B are connected on the core rod A, a clamping die C is in an initial state as shown in fig. 1, a section of circular hollow straight pipe blank D is sleeved on a connecting piece of the core rod A and 2 core balls (wherein, a gap of about 0.5mm is formed between the inner diameter of the pipe and the core rod, and the interval between the core balls is generally 10mm), then the clamping die is closed as shown in fig. 2, and the clamping die C and a wheel die E start to rotate around a central hole of the wheel die E for a certain angle after the die is closed, so as to obtain the required twisted pipe.
The prior patent document CN 103691762A discloses a method for manufacturing a double-layer pipe with a complex shape, which comprises the steps of firstly coaxially placing pipe blanks with different diameters, welding and reinforcing two ends of the pipe blanks with a sealing device, and then bending and deforming; then injecting high-pressure liquid into the gap between the inner pipe and the outer pipe, pressurizing the inner pipe and the gap between the inner pipe and the outer pipe simultaneously, controlling the liquid pressure difference between the inner pipe and the outer pipe to increase the gap between the inner pipe and the outer pipe, enabling the inner pipe to reach the required shape, and finally releasing the high-pressure liquid. And vacuumizing the gap between the inner pipe and the outer pipe, and sealing the inner pipe and the outer pipe at two ends of the double-layer pipe to finally obtain the double-layer pipe. The method comprises the steps of welding a sealing device on a double-layer pipe to form the double-layer pipe, pressing the double-layer pipe into C-shaped, V-shaped and L-shaped pipes through 3 cylinders in a three-roller bending mode, pressurizing the inside and the outside of a product in a pressure difference mode to obtain the shape required by the product, and finally cutting off the sealing device.
However, the inner pipe is deformed after the double-layer pipe is bent, the structure of the double-layer pipe is changed after the double-layer pipe is bent, the whole section becomes uneven, and particularly, wrinkling or irregular deformation occurs in the roll bending process, and the wrinkling occurs. And then the hydraulic forming is used for increasing the pressure to the gap between the inner pipe and the outer pipe to open the gap of the double-layer pipe. The crimping station forms numerous small rounded corners, according to the hydroforming formula: p is δ t/r, modern hydroforming technology, formula P is shaping pressure, δ is flow pressure during shaping, t is average thickness at transition round corner, r is minimum round corner (wrinkling small round corner) of transition region, so that the smaller the pressure value required for bulging is, the pressure value required for areas far away from wrinkling area is, and hydroforming, the pressure value of each area is the same, so the same pressure value cannot mold products to required size at all, or wrinkles cannot be stretched, or wrinkles far ends are stretched or cracked. The method has the advantages that the method cannot realize the propping of the gap after the pressure deformation or ensure the forming quality, and the sealing device needs to be cut off every time, so that the sealing device cannot be reused, the great waste is caused, and the continuous operation cannot be realized.
Disclosure of Invention
The technical problem to be solved by the invention is how to improve the forming quality of the double-layer twisted tube and reduce the production cost.
The invention solves the technical problems through the following technical means: an inner low-pressure bending forming device of a double-layer twisted pipe is used for bending and forming the double-layer pipe body, the double-layer pipe body comprises an outer pipe and an inner pipe, and comprises a right die, a left die, a core ball, a sealing element and an oil cylinder, the right die is pressed on the left die and enclosed to form a forming cavity, the double-layer tube body is attached to the forming cavity wall, the core ball is positioned in the area to be wound and bent in the double-layer pipe body, the sealing element is fixed at the two ends of the double-layer pipe body, and forms a closed cavity with the clearance between the outer pipe and the inner pipe, the oil cylinder is fixedly arranged at the outer side of the sealing element, a liquid storage cavity is arranged in the oil cylinder and is connected with a second oil cylinder piston rod in a sliding way, the second oil cylinder piston rod is connected with a first external driving device, one end, facing the closed cavity, of the liquid storage cavity is communicated with the closed cavity, and the first external driving device drives the piston rod of the second oil cylinder to move towards the double-layer pipe body.
Fix at double-deck body both ends through the sealing member to enclose with the clearance between outer tube, the inner tube and form airtight cavity, need not to cut the end cap position, improved material utilization, practiced thrift the cost, carry on spacingly through the core ball to the inner tube before the bending, annotate liquid medium in airtight cavity, can be to preventing inner tube, outer tube corrugating at the pipe winding in-process, improved shaping quality and efficiency.
As preferred technical scheme, the sealing member includes first end cap and second end cap, first end cap joint deviates from the one end of hydro-cylinder at double-deck body, and its one end that deviates from double-deck body is connected with the outside drive arrangement of second, the output of the outside drive arrangement of second drives double-deck body and feeds along its axis direction, the second end cap is located double-deck body towards the one end of hydro-cylinder and extends to the clearance of inner tube and outer tube in, through the setting of the outside drive arrangement of second, can make first end cap, double-deck body, second end cap be airtight cavity structures all the time, has improved around the shaping effect of bending.
As a preferred technical scheme, the first plug is connected with a center rod in a sliding mode, and the center rod is movably connected with a core ball through an inner shaft core.
According to a preferable technical scheme, the core ball comprises a first core ball and a second core ball, the first core ball and the second core ball are connected through a universal joint, the first core ball is connected with the inner shaft core through another universal joint, and the first core ball, the second core ball and the universal joint are arranged to perfectly fit the winding of the double-layer pipe body.
As preferred technical scheme, the second end cap links to each other with third external drive device, third external drive device drive second end cap feeds or returns towards double-deck body, the first hydro-cylinder piston rod of second end cap tip fixedly connected with, first hydro-cylinder piston rod and hydro-cylinder sliding connection, the cooperation of second end cap and double-deck body joint to extend to in the airtight cavity, the water injection hole has been seted up to the second end cap, the water injection hole is through seting up pore and the liquid reserve cavity intercommunication at first hydro-cylinder piston rod.
As preferred technical scheme, left side mould includes workstation, wheel mould, crease-resistance mould, the wheel mould rotates to be connected at the workstation top, crease-resistance mould and workstation fixed connection, well core rod deviates from the one end of double-deck body fixed with the workstation, prevents around the inboard wrinkling of bending in-process body through the crease-resistance mould.
According to a preferable technical scheme, the right die comprises a clamping die, and the clamping die and the wheel die are pressed to fix the double-layer pipe body.
According to the preferable technical scheme, the right die further comprises a guide die, the guide die is arranged on the outer side of the double-layer tube body in a sliding mode along the axial direction of the double-layer tube body and attached to the tube wall of the double-layer tube body, and deformation of the outer side of the double-layer tube body can be compensated through the guide die.
As preferred technical scheme, outer tube and inner tube are coaxial setting, and the outer tube internal diameter is greater than the inner tube external diameter, outer tube and inner tube both ends are connected with first end cap and second end cap joint respectively, the joint face of first end cap, second end cap and outer tube and inner tube all is equipped with the sealing washer, through the setting of sealing washer, has improved sealed effect.
As a preferred technical scheme, a pressure sensor is arranged in a liquid storage cavity of the oil cylinder.
An inner low-pressure winding forming method of a double-layer twisted pipe comprises the following steps:
positioning a core ball to a region to be bent in a double-layer pipe body;
two ends of the double-layer pipe body are respectively attached to the sealing element, so that the sealing element and a gap between the outer pipe and the inner pipe of the double-layer pipe body are enclosed to form a closed cavity;
injecting a liquid medium into the liquid storage cavity, feeding the liquid medium through a piston rod of a second oil cylinder, compressing the liquid medium in the liquid storage cavity and filling the closed cavity with the liquid medium;
(IV) continuously feeding a piston rod of the second oil cylinder to increase the pressure P of the gap in the double-layer pipe body until the pressure P reaches the yield pressure for deforming the outer pipe;
fixing the double-layer pipe body, bending and forming the double-layer pipe body, feeding the double-layer pipe body through a second oil cylinder piston rod, and compensating the pressure in the closed cavity in the bending process;
sixthly, controlling a piston rod of the second oil cylinder to return, wherein the liquid medium flows back into the oil cylinder due to pressure difference;
and (seventhly), resetting the sealing element and taking out the product.
As a preferred technical solution, the step (iv) further includes: and detecting the pressure value P of the closed cavity, comparing the pressure value P with the standard value of the yield pressure, and driving the telescopic rod of the second oil cylinder to move towards the second plug through the first external driving device when the pressure value P is lower than the standard value of the yield pressure so as to complement the pressure value until the preset bending angle is reached.
The invention has the advantages that:
(1) according to the invention, the sealing elements are fixed at two ends of the double-layer pipe body and form the closed cavity by enclosing with the gap between the outer pipe and the inner pipe, the cutting of the plug part is not needed, the material utilization rate is improved, the cost is saved, meanwhile, the inner pipe is limited by the core ball before the bending, the liquid medium is filled in the closed cavity, the inner pipe and the outer pipe can be prevented from wrinkling in the pipe winding process, and the forming quality and efficiency are improved.
(2) According to the invention, the first plug, the double-layer pipe body and the second plug can be always in a closed cavity structure through the arrangement of the second external driving device, so that the bending forming effect is improved, the labor intensity of an operator is reduced, and the double-layer pipe body does not need to be carried.
Drawings
FIG. 1 is a schematic structural diagram of an initial (open) state of a wrap-around process according to the background of the present invention;
fig. 2 is a schematic structural diagram of a mold in a closed state for a wrap-around bending process according to the background art of the present invention;
fig. 3 is a schematic cross-sectional view of an internal low-pressure bending apparatus for forming a double-layer twisted pipe according to an embodiment of the present invention;
fig. 4 is a schematic bottom view of an internal low-pressure bending apparatus for forming a double-layer twisted pipe according to an embodiment of the present invention;
fig. 5 is an enlarged partial structural view of a portion a in fig. 3 of an internal low-pressure bending forming apparatus for a double-layer twisted pipe according to an embodiment of the present invention;
fig. 6 is an enlarged partial structural view of B in fig. 3 of an internal low-pressure bending apparatus for forming a double-layer twisted pipe according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an internal low-pressure bending forming apparatus for a double-layer twisted pipe according to an embodiment of the present invention;
fig. 8 is a schematic structural view of a double-layer tube body of an internal low-pressure bending forming device for a double-layer twisted tube according to an embodiment of the present invention;
reference numerals: 1. an outer tube; 2. an inner tube; 3. a first plug; 4. a second plug; 5. a center pole; 6. an inner shaft core; 7. a work table; 8. a wheel mold; 9. clamping a mold; 10. an oil cylinder fixing seat; 11. an oil cylinder; 12. a first cylinder piston rod; 13. a second cylinder piston rod; 14. a first core ball; 15. a second core ball; 16. a universal joint; 17. a water injection hole; 18. a crease-resist die; 19. guiding a mold; 20. a pressure sensor.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 3 and 4, an inner low pressure wrap-around forming device for a double-layer twisted pipe comprises: the device comprises an outer pipe 1, an inner pipe 2, a right die, a left die, a first plug 3, a second plug 4, a central rod 5, an inner shaft core 6, an oil cylinder fixing seat 10, an oil cylinder 11, a first oil cylinder piston rod 12, a second oil cylinder piston rod 13, a core ball, a pressure sensor 20 and a controller, wherein the left die comprises a workbench 7, a wheel die 8 and a crease-resistant die 18, the right die comprises a clamping die 9 and a guide die 19, refer to figure 5, and the device also comprises a universal joint 16, wherein, the inner low pressure indicates that the pressure of the liquid medium does not reach the yield pressure for deforming the pipe body, in the embodiment, the sealing elements are a first plug 3 and a second plug 4, the adopted external driving devices are hydraulic cylinders, the driving mechanism can be other driving mechanisms with linear movement functions, and is not limited to the driving mechanism, the external driving mechanism is electrically connected with the controller, the liquid medium can be any liquid, and the liquid medium can also be gas; the pressure sensor 20 is electrically connected with the controller, the outer pipe 1 and the inner pipe 2 are both hollow tubular structures, the hollow tubular structures are coaxially arranged to form a double-layer pipe body, the inner diameter of the outer pipe 1 is larger than the outer diameter of the inner pipe 2, the inner pipe 2 is positioned in the outer pipe 1, two ends of the outer pipe 1 and the inner pipe 2 are respectively connected with a first plug 3 and a second plug 4 in a clamping way, the first plug 3 is clamped at one end of the double-layer pipe body, which is far away from the oil cylinder 11, one end of the double-layer pipe body, which is far away from the double-layer pipe body, is connected with a second external driving device, the output end of the second external driving device drives the double-layer pipe body to feed rightwards along the axis of the double-layer pipe body, the second plug 4 is positioned at one end of the double-layer pipe body, the second plug 4 is connected with a third external driving device, the third external driving device drives the second plug 4 to feed or return to the double-layer pipe body, the clamping surfaces of the first plug 3, the second plug 4, the outer pipe body and the inner pipe 2 are respectively provided with a sealing ring, the gaps between the first plug 3, the second plug 4, the outer tube 1 and the inner tube 2 are enclosed to form a closed cavity structure, the clamping ends of the first plug 3, the second plug 4 and the double-layer tube body all extend into the gap between the outer tube 1 and the inner tube 2, and it should be noted that the positions of the wheel mold 8 and the clamping mold 9 can be set according to actual production.
Referring to fig. 3 and 4, a wheel mold 8 is rotatably connected to the top of a workbench 7, an external drive is arranged on the workbench 7 and is in transmission fit with a clamping mold 9, the clamping mold 9 is pressed on the wheel mold 8 to form a forming cavity, a double-layer tube body is attached to the forming cavity, the double-layer tube body is fixed with the wheel mold 8 through the clamping mold 9, the wheel mold 8 is fixedly connected with an oil cylinder 11 through an oil cylinder fixing seat 10, a liquid storage cavity is arranged in the oil cylinder 11 and is slidably connected with a second oil cylinder piston rod 13, one end of the second oil cylinder piston rod 13 is located in the liquid storage cavity, the other end of the second oil cylinder piston rod 13 is connected with a first external drive device, one end of the liquid storage cavity facing the sealed cavity is communicated with the sealed cavity, and the liquid storage cavity is filled with a liquid medium; first external drive device drive second cylinder piston rod 13 moves and fills airtight cavity towards double-deck body and with liquid medium, the stock solution intracavity is equipped with pressure sensor 20, pressure sensor 20 detectable hydro-cylinder 11 stock solution intracavity pressure value and feed back to the controller, adjust first external drive device through the controller and drive second cylinder piston rod 13 and move, complement the pressure value, in the process of bending, the outside of double-deck body is drawn, the inboard pressurized, the length that the outside was drawn can be longer than the inboard, therefore pressure can descend, when descending to a certain degree, the phenomenon of corrugating can appear in outer tube 1, can not guarantee the size and the quality of product.
Referring to fig. 1 and 5, the core ball includes a first core ball 14 and a second core ball 15, the first plug 3 is slidably connected with a center rod 5, the center rod 5 is movably connected with the first core ball 14 and the second core ball 15 through an inner shaft core 6, the number of the core balls can be increased according to actual bending, the number of the core balls is not limited to two, the core balls are connected through a universal joint 16, specifically, the first core ball 14 is rotatably connected with the second core ball 15 through the universal joint 16, and the first core ball 14 is rotatably connected with the inner shaft core 6 through the universal joint 16; the second plug 4 is connected with a third external driving device, the third external driving device drives the second plug 4 to feed or return towards the double-layer pipe body, a first oil cylinder piston rod 12 is fixedly connected to the end portion of the second plug 4, the first oil cylinder piston rod 12 is in sliding connection with the oil cylinder 11, the second plug 4 is in clamping fit with the double-layer pipe body and extends into the closed cavity, referring to fig. 6, a water injection hole 17 is formed in the second plug 4, the water injection hole 17 is communicated with the liquid storage cavity through a hole channel formed in the first oil cylinder piston rod 12, the first oil cylinder piston rod 12 is in sliding connection with the oil cylinder 11, the right end face of the first oil cylinder piston rod 12, the inner wall of the oil cylinder 11 and the left end face of the second oil cylinder piston rod 13 are enclosed to form the liquid storage cavity.
Referring to fig. 3, a crease-resist die 18 is fixedly connected to the worktable 7, a driving mechanism is provided at one end of the central rod 5 away from the double-layer tube body, the driving mechanism is fixedly connected to the worktable 7, and after the bending is completed, the central rod 5 is reset, and in the initial state, the first core ball 14 is extended into the area to be bent through the driving structure, to fix the position of the central rod 5 and ensure the bending effect, the guide die 19 is arranged outside the double-layer pipe body in a sliding way along the axial direction of the double-layer pipe body, and is attached to the pipe wall of the double-layer pipe body, the bottom of the workbench 7 is connected with a driving mechanism of a guide die 19, the driving mechanism is electrically connected with the controller, the guide die 19 continuously moves in the bending process and is attached to the double-layer pipe body, only one bending process is shown in the embodiment, and an optional device can be added on the oil cylinder fixing seat 10 or the oil cylinder 11 to realize one-step forming of multiple bends.
The using method comprises the following steps:
positioning a core ball to a region to be bent in a double-layer pipe body;
two ends of the double-layer pipe body are respectively attached to the first plug 3 and the second plug 4; the outer pipe 1 and the inner pipe 2 are coaxially placed and are in clamping fit with the first plug 3, a second external driving device connected with the first plug 3 is kept still, a first oil cylinder piston rod 12 is driven by a third external driving device to drive the second plug 4 to move towards the double-layer pipe body, and the first plug 3, a gap between the inner pipe and the outer pipe and the second plug 4 are enclosed to form a closed cavity structure;
injecting a liquid medium into a liquid storage cavity in the oil cylinder 11, driving a second oil cylinder piston rod 13 to feed through a first external driving device, compressing the liquid medium in the liquid storage cavity and filling the closed cavity with the liquid medium;
(IV) the piston rod 13 of the second oil cylinder continues to feed, so that the pressure P of the gap in the double-layer pipe body is increased until the pressure P reaches the yield pressure for deforming the outer pipe; and a pressure sensor 20 is arranged in the liquid storage cavity to detect the pressure value;
(V) fix the double-deck body to the double-deck body is around the bending shaping, and to feeding through second hydro-cylinder piston rod, compensate the pressure in the airtight cavity of winding in-process, specifically as follows: the clamping die 9 moves towards one side of the wheel die 8 to clamp the double-layer pipe body; the clamping die 9 and the wheel die 8 are rotated to corresponding angles around the wheel die center hole, and in the rotation process of the wheel die 8, the second external driving device drives the first plug 3 to synchronously feed towards the moving direction of the double-layer pipe body, so that the first plug 3, the double-layer pipe body and the second plug 4 are always kept in a closed state; meanwhile, according to the comparison between the detection value P of the pressure sensor 20 and the yield pressure, when the detection value P is lower than the standard value of the yield pressure, the first external driving device drives the second oil cylinder telescopic rod 13 to move towards the second plug 4, and the pressure value is complemented until the preset bending angle is reached;
sixthly, controlling the piston rod 13 of the second oil cylinder to return, and enabling the liquid medium to flow back into the oil cylinder 11 due to the pressure difference;
and (seventhly), the second plug 4 is driven by a third external driving device to reset the first oil cylinder piston rod 12, and the product after being wound can be taken out.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (12)
1. An inner low-pressure bending forming device of a double-layer twisted pipe is used for bending and forming the double-layer pipe body, the double-layer pipe body comprises an outer pipe (1) and an inner pipe (2) and is characterized by comprising a right die, a left die, a core ball, a sealing element and an oil cylinder (11), the right die is pressed on the left die and enclosed to form a forming cavity, the double-layer pipe body is attached to the forming cavity, the core ball is located in a region to be bent in the double-layer pipe body, the sealing element is fixed at two ends of the double-layer pipe body and is enclosed with a gap between the outer pipe (1) and the inner pipe (2) to form a closed cavity, the oil cylinder (11) is fixedly arranged outside the sealing element, a liquid storage cavity is arranged in the oil cylinder (11) and is connected with a second oil cylinder piston rod (13) in a sliding mode, the second oil cylinder piston rod (13) is connected with a first external driving device, and one end of the liquid storage cavity, facing the closed cavity, is communicated with the closed cavity, and the first external driving device drives a piston rod (13) of the second oil cylinder to move towards the double-layer pipe body.
2. The inner low-pressure bending forming device for the double-layer twisted pipe according to claim 1, wherein the sealing element comprises a first plug (3) and a second plug (4), the first plug (3) is connected to one end, deviating from the oil cylinder (11), of the double-layer pipe body in a clamping manner, a second external driving device is connected to one end, deviating from the double-layer pipe body, of the first plug (3), an output end of the second external driving device drives the double-layer pipe body to feed along the axis direction of the double-layer pipe body, and the second plug (4) is located at one end, facing the oil cylinder (11), of the double-layer pipe body and extends into a gap between the inner pipe (2) and the outer pipe (1).
3. The internal low-pressure bending forming device for the double-layer twisted pipe according to claim 2, wherein the first plug (3) is slidably connected with a central rod (5), and the central rod (5) is movably connected with the core ball through an internal shaft core (6).
4. The internal low pressure bending forming device of the double-layer twisted pipe according to claim 3, wherein the core ball comprises a first core ball (14) and a second core ball (15), the first core ball (14) and the second core ball (15) are connected through a universal joint (16), and the first core ball (14) is connected with the inner shaft core (6) through another universal joint (16).
5. The inner low-pressure bending forming device for the double-layer twisted pipe according to claim 3, wherein the second plug (4) is connected with a third external driving device, the third external driving device drives the second plug (4) to feed or return towards the double-layer pipe body, a first oil cylinder piston rod (12) is fixedly connected to the end of the second plug (4), the first oil cylinder piston rod (12) is connected with the oil cylinder (11) in a sliding manner, the second plug (4) is connected with the double-layer pipe body in a clamping manner and provided with a water injection hole (17), and the water injection hole (17) is communicated with the liquid storage cavity through a hole channel formed in the first oil cylinder piston rod (12).
6. The internal low-pressure bending forming device for the double-layer twisted pipe according to claim 5, wherein the left die comprises a workbench (7), a wheel die (8) and a crease-resistant die (18), the wheel die (8) is rotatably connected to the top of the workbench (7), the crease-resistant die (18) is fixedly connected with the workbench (7), and one end, away from the double-layer pipe body, of the central rod (5) is fixed with the workbench (7).
7. The internal low-pressure bending forming device for the double-layer twisted pipe according to claim 6, wherein the right die comprises a clamping die (9), and the clamping die (9) is pressed with the wheel die (8) to fix the double-layer pipe body.
8. The internal low pressure bending forming device of the double-layer twisted pipe according to claim 7, wherein the right mold further comprises a guide mold (19), and the guide mold (19) is slidably disposed outside the double-layer pipe along the axial direction of the double-layer pipe and abuts against the wall of the double-layer pipe.
9. The inner low-pressure bending forming device for the double-layer twisted pipe according to claim 5, wherein the outer pipe (1) and the inner pipe (2) are coaxially arranged, the inner diameter of the outer pipe (1) is larger than the outer diameter of the inner pipe (2), two ends of the outer pipe (1) and two ends of the inner pipe (2) are respectively connected with the first plug (3) and the second plug (4) in a clamping mode, and sealing rings are arranged on clamping surfaces of the first plug (3) and the second plug (4) and clamping surfaces of the outer pipe (1) and the inner pipe (2).
10. The internal low-pressure winding and forming device for the double-layer twisted pipe as claimed in claim 1, wherein a pressure sensor (20) is arranged in a liquid storage cavity of the oil cylinder (11).
11. An internal low-pressure winding forming method of a double-layer twisted pipe is characterized by comprising the following steps:
positioning a core ball to a region to be bent in a double-layer pipe body;
two ends of the double-layer pipe body are respectively attached to the sealing element, so that the sealing element and a gap between the outer pipe (1) and the inner pipe (2) of the double-layer pipe body are enclosed to form a closed cavity;
thirdly, liquid medium is injected into a liquid storage cavity of the oil cylinder (11) and fed through a second oil cylinder piston rod (13), the liquid medium in the liquid storage cavity is compressed, and the closed cavity is filled with the liquid medium;
(IV) continuing feeding a piston rod (13) of the second oil cylinder to increase the pressure P of the gap in the double-layer pipe body until the pressure P reaches the yield pressure for deforming the outer pipe;
fixing the double-layer pipe body, bending and forming the double-layer pipe body, and feeding through a second oil cylinder piston rod (13) to compensate the pressure in the closed cavity in the bending process;
sixthly, controlling a piston rod (13) of the second oil cylinder to retreat;
and (seventhly), resetting the sealing element and taking out the product.
12. The internal low pressure wrap-around forming method of a double-layer twisted tube as claimed in claim 11, wherein the step (iv) further comprises: and detecting the pressure value P of the closed cavity, comparing the pressure value P with the standard value of the yield pressure, and driving the second oil cylinder telescopic rod (13) to move towards the second plug (4) through the first external driving device when the pressure value P is lower than the standard value of the yield pressure so as to complement the pressure value until the preset bending angle is reached.
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| Publication number | Priority date | Publication date | Assignee | Title |
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|---|---|
| CN114289574B (en) | 2023-05-02 |
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