Electrically-assisted bending forming device and method for gap double-wall guide pipe

Abstract

The invention relates to an electric auxiliary bending forming device and method for a gap double-wall guide pipe, and relates to the field of metal pipe bending forming machining. The electric auxiliary bending forming device comprises a front end cover, an electric conduction part, a first front inserting groove and a second front inserting groove, the first front inserting groove is provided with an outer inserting pipe layer, and the second front inserting groove is provided with an inner inserting pipe layer; the rear end cover comprises an outer conductive layer which is provided with a first rear slot for plugging the outer layer of the pipe; the inner conductive layer is provided with a second rear slot for inserting the inner layer of the pipe; the insulating layer is arranged between the outer conductive layer and the inner conductive layer; one end of the steel wire rope is connected with the front end cover, and the other end penetrates through the rear end cover, is electrically connected with the inner conductive layer and is insulated from the outer conductive layer. The two layers of the gap double-wall conduit are connected in series, the connection objects of the positive electrode and the negative electrode of the power supply are located at the same end of the gap double-wall conduit, the needed line is short, the electric energy consumption of bending forming of the gap double-wall conduit is reduced, and the possibility of aging failure of the line caused by local overheating of the line is reduced; and the response precision and the response speed of the gap double-wall guide pipe on power supply parameter adjustment are improved.

Description

Technical Field

[0001] The present invention relates to the field of metal pipe bending forming processing, and particularly to an electro-assisted bending forming device and method for an interstitial double-wall conduit. Background Art

[0002] The interstitial double-wall conduit has become an optimal structure in key fields such as the fuel pipeline of aerospace engines and the hydraulic control system of fighter jets. The conduit realizes energy buffering and sensor integration through the interstitial layer between the two layers of conduits, can withstand extreme working conditions, and significantly improves the reliability of the system.

[0003] Chinese Patent CN116475281A discloses an electro-pulse type double-wall metal pipe bending auxiliary forming device, including: a front-end limit unit of the pipe joint, which is provided with a first gap chute and a second gap chute for the end of the double-wall pipe assembly to be inserted and maintained in sliding connection at its end, and an electro-pulse application unit; a pressure application driving unit, including a driving bolt rod, a butting component fixedly connected to the left side of the front-end limit unit of the pipe joint and internally provided with an axial sliding connection hole for the driving bolt rod, and a driving nut; hard filling particles filled between the outer wall pipe and the inner wall pipe; a rear-end limit unit of the pipe joint; by adding two groups of pipe fitting positioning chutes in the front-end limit unit of the pipe joint, the limit pressure application suitable for the bending of double-wall pipe fittings is realized. In addition, by adding an electro-pulse application unit, the device can utilize the electric field to improve the plasticity of metal pipe fittings.

[0004] When using the above device to bend the interstitial double-wall conduit, the power supply is connected to both ends of the interstitial double-wall conduit. The required circuit is relatively long, the circuit resistance is relatively large, the energy consumption is relatively large, the possibility of circuit aging and failure due to local overheating is relatively large, and the response accuracy and response speed of the interstitial double-wall conduit to the adjustment of power supply parameters are limited. Summary of the Invention

[0005] Aiming at the problems in the existing electro-pulse type double-wall metal pipe bending auxiliary forming device that the power supply is connected to both ends of the interstitial double-wall conduit, the required circuit is relatively long, the circuit resistance is relatively large, the energy consumption is relatively large, the possibility of circuit aging and failure due to local overheating is relatively large, and the response accuracy and response speed of the interstitial double-wall conduit to the adjustment of power supply parameters are limited, the present invention provides an electro-assisted bending forming device and method for an interstitial double-wall conduit. During the bending forming, the connection objects of the positive and negative poles of the power supply are both at the same end of the interstitial double-wall conduit, and the required circuit is shorter, so as to solve the technical problems of relatively large energy consumption, relatively large possibility of circuit aging and failure due to local overheating, and limited response accuracy and response speed of the interstitial double-wall conduit to the adjustment of power supply parameters.

[0006] The present invention provides an electro-assisted bending and forming device for a gap double-wall catheter, comprising: a front end cap, which is a conductive structure and is provided with a first front slot for inserting the outer layer of the gap double-wall catheter and a second front slot for inserting the inner layer of the gap double-wall catheter.

[0007] A rear end cap, comprising: an outer conductive layer, which is provided with a first rear slot for inserting the outer layer of the gap double-wall catheter. An inner conductive layer, which is arranged inside the outer conductive layer and is provided with a second rear slot for inserting the inner layer of the gap double-wall catheter. An insulating layer, which is arranged between the outer conductive layer and the inner conductive layer.

[0008] A steel wire rope, one end of which is connected to the front end cap, and the other end passes through the rear end cap and is electrically connected to the inner conductive layer and insulated from the outer conductive layer.

[0009] In some embodiments, the electro-assisted bending and forming device further comprises:

[0010] Insulating particles, which are filled inside the inner layer of the gap double-wall catheter and between the two layers of the gap double-wall catheter.

[0011] In some embodiments, the purity of alumina in the insulating particles is 99%.

[0012] In some embodiments, the particle size of the insulating particles is 1-3 mm.

[0013] In some embodiments, the electro-assisted bending and forming device further comprises:

[0014] A power supply, which is connected to the end of the steel wire rope away from the front end cap and the outer conductive layer.

[0015] In some embodiments, the positive pole of the power supply is connected to the outer conductive layer, and the negative pole of the power supply is connected to the steel wire rope.

[0016] In some embodiments, the power supply provides a periodic pulsed current to the gap double-wall catheter. The pulse width of the power supply is less than 1 ms.

[0017] In some embodiments, the electro-assisted bending and forming device further comprises:

[0018] A spherical bearing.

[0019] A bending ball die, which is connected to the inner ring of the spherical bearing and has a pipe forming channel inside.

[0020] A guiding mechanism, which is connected to the bending ball die and has a pipe guiding channel communicated with the pipe forming channel inside.

[0021] In some embodiments, the front end cap is located on the side of the bending ball die away from the guiding mechanism, and the rear end cap is located on the side of the guiding mechanism away from the bending ball die.

[0022] The present invention also provides an electro-assisted bending forming method for a clearance double-wall catheter, using the electro-assisted bending forming device for the clearance double-wall catheter described above to perform the bending forming of the clearance double-wall catheter; during the bending forming, one end of the steel wire rope away from the front end cap and the outer conductive layer are both connected to a power source.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. During the bending forming, the inner and outer layers of the clearance double-wall catheter form a series circuit, and the connection objects of the positive and negative poles of the power source are located at the same end of the clearance double-wall catheter. The required circuit is shorter, which helps to reduce the power consumption of the bending forming of the clearance double-wall catheter, reduce the possibility of the circuit aging and failing due to local overheating, and improve the response accuracy and response speed of the clearance double-wall catheter to the adjustment of power source parameters.

[0025] 2. During the bending process, both the inner and outer tube walls of the clearance double-wall catheter are supported by insulating particles, so that the wall thickness change of the bent part of the clearance double-wall catheter is uniform, and the clearance of the bent part of the clearance double-wall catheter is kept uniform. The degree of cross-section distortion of the pipe material will be greatly reduced, and the situations of bending instability and wrinkling and serious wall thickness change will also be improved. Description of the Drawings

[0026] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 is a schematic diagram of the use state of the electro-assisted bending forming device in the present invention;

[0028] Figure 2 is Figure 1 an enlarged schematic diagram of area A in

[0029] Figure 3 is Figure 2 an enlarged schematic diagram of area B in

[0030] In the figure:

[0031] 1. Front end cap; 11. First front slot; 12. Second front slot; 2. Rear end cap; 21. Outer conductive layer; 211. First rear slot; 22. Inner conductive layer; 221. Second rear slot; 23. Insulating layer; 3. Steel wire rope; 4. Spherical bearing; 5. Bending ball die; 6. Guiding mechanism; 7. Clearance double-wall catheter; 71. Inner layer; 72. Outer layer; 8. Bracket; 9. Pressing mechanism. Detailed Embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0034] The terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or more of such features.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection. It may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] As shown in the appendix Figures 1 - 3 In a schematic embodiment of the electro-assisted bending forming device for the gap double-wall catheter of the present invention, the electro-assisted bending forming device for the gap double-wall catheter at least includes:

[0037] The front end cover 1, which is a conductive structure, is provided with a first front slot 11 for inserting the outer layer 72 of the gap double-wall catheter 7 and a second front slot 12 for inserting the inner layer 71 of the gap double-wall catheter 7.

[0038] The rear end cover 2 includes: an outer conductive layer 21, which is provided with a first rear slot 211 for inserting the outer layer 72 of the gap double-wall catheter 7. An inner conductive layer 22, which is arranged inside the outer conductive layer 21 and is provided with a second rear slot 221 for inserting the inner layer 71 of the gap double-wall catheter 7. An insulating layer 23, which is arranged between the outer conductive layer 21 and the inner conductive layer 22.

[0039] The steel wire rope 3 is connected to the front end cover 1 at one end, and passes through the inner conductive layer 22, the insulating layer 23 and the outer conductive layer 21 at the other end, and is electrically connected to the inner conductive layer 22 and insulated from the outer conductive layer 21.

[0040] The above-mentioned electro-assisted bending forming device is used to bend and form the gap double-wall conduit 7; during the bending and forming process, one end of the steel wire rope 3 far from the front end cover 1 and the outer conductive layer 21 are both connected to the power supply, so that the inner layer 71 and the outer layer 72 of the gap double-wall conduit 7 form a series circuit, and the connection objects of the positive and negative poles of the power supply are located at the same end of the gap double-wall conduit 7. The required circuit is shorter, which helps to reduce the power consumption of the bending and forming of the gap double-wall conduit 7, reduce the possibility of the circuit aging and failure due to local overheating, and improve the response accuracy and response speed of the gap double-wall conduit 7 to the adjustment of the power supply parameters.

[0041] In some embodiments, the electro-assisted bending forming further includes: insulating particles filled inside the inner layer 71 of the gap double-wall conduit 7 and between the inner layer 71 and the outer layer 72 of the gap double-wall conduit 7. The insulating particles are not shown in the figure.

[0042] During the bending process of the gap double-wall conduit 7, both the inner layer 71 and the outer layer 72 of the gap double-wall conduit 7 will be supported by the insulating particles to disperse the stress concentration inside the pipe material, inhibit the excessive stretching of the part with a larger bending radius and the compressive deformation of the part with a smaller bending radius, so that the wall thickness change of the bent part of the gap double-wall conduit 7 is uniform, and the gap of the bent part of the gap double-wall conduit 7 is kept uniform. The internal pressure provided by the insulating particles offsets part of the tensile stress and compressive stress in the radial direction of the pipe material, and the degree of cross-section distortion of the pipe material will be greatly reduced, and the situations of bending instability and wrinkling and serious wall thickness change will also be improved.

[0043] Under the same experimental conditions, based on the above-mentioned electro-assisted bending forming device, two groups of pipe bending experiments are carried out using the same front end cover 1, rear end cover 2 and steel wire rope 3. In one group of experiments, insulating particles are filled in the gap double-wall conduit 7, and in the other group of experiments, insulating particles are not filled in the gap double-wall conduit 7. Based on the experimental results, it can be found that when the insulating particles are not filled, the maximum wall thickness reduction rate of the bent pipe material can reach 30%, and the maximum ovality of the cross-section of the bent part of the pipe material can reach 25%. After filling the insulating particles, the wall thickness reduction rate of the pipe material can be reduced to less than 8%, the ovality of the cross-section of the bent part of the pipe material can be controlled within 7%, and the frictional force between the insulating particles and the pipe wall can partially offset the elastic springback effect after bending, which can reduce the springback angle by about 15% - 40%.

[0044] In the electro-assisted bending forming scheme of the conventional clearance double-wall catheter 7, the clearance double-wall catheter 7 is usually filled with conductive particles. The current forms a loop through the conductive particles and the pipe material. The Joule heat acts on both the conductive particles and the pipe material simultaneously, which will cause current loss and energy waste. At the same time, the action of the current will also cause the stiffness of the conductive particles to decrease. When the temperature is too high, the conductive particles may adhere to each other, resulting in poor fluidity of the conductive particles and local stress concentration. Due to the decrease in fluidity, the filling compactness will also become poor, thus causing the supporting force on the pipe wall to decrease. In addition, due to the conductivity of the conductive particles, the electric field distribution will also be changed, and an eddy current effect may be formed, resulting in an additional electromagnetic force at the interface between the conductive particles and the pipe material. This electromagnetic force will cause the conductive particles to vibrate or migrate, thus affecting the supporting effect of the pipe wall.

[0045] When the clearance double-wall catheter 7 is filled with insulating particles, the current is only transmitted through the pipe material itself. The energy is concentrated on the pipe material, which helps to improve the response accuracy and response speed of the clearance double-wall catheter 7 to the adjustment of power supply parameters. At the same time, the movement of the insulating particles depends on mechanical friction and pressure and is not interfered by the current. During the bending process of the pipe material, the insulating particles inside the pipe material have better fluidity and better supporting force on the pipe wall.

[0046] Furthermore, when the particle size of the insulating particles is uniform and the filling density in the clearance double-wall catheter 7 is 70%-85%, the insulating particles can provide a relatively uniform supporting effect on the pipe wall of the clearance double-wall catheter 7 during the electro-assisted bending forming process. During the electro-assisted bending forming process, the pipe material is not prone to local deformation concentration, and the fluidity of the insulating particles is good, which helps to improve the filling efficiency of the insulating particles.

[0047] When the filling density of the insulating particles with uniform particle size in the clearance double-wall catheter 7 is greater than 85%, the inter-particle voids of the insulating particles are small, and the supporting effect on the pipe wall is good, but the fluidity is poor, which is not conducive to rapid filling. And during the electro-assisted bending forming, it is necessary to significantly increase the pressure inside the clearance double-wall catheter 7 to achieve a better forming effect.

[0048] When the filling density of the insulating particles with uniform particle size in the clearance double-wall catheter 7 is less than 70%, the fluidity of the insulating particles in the clearance double-wall catheter 7 is good, which is conducive to rapid filling, but the inter-particle voids are large, and the support for the pipe wall is discontinuous, which is easy to cause local deformation concentration.

[0049] Furthermore, the position of the front end cover 1 or the rear end cover 2 in the length direction of the steel wire 3 is adjustable, so as to tighten the steel wire 3 between the front end cover 1 and the rear end cover 2, so that the front end cover 1 and the rear end cover 2 squeeze the insulating particles in the gap double-wall conduit 7, thereby increasing the pressure in the gap double-wall conduit 7. By changing the tension of the steel wire 3 between the front end cover 1 and the rear end cover 2 and the length of the steel wire 3, the pressure in the gap double-wall conduit 7 can be adjusted, thereby adjusting the supporting effect of the insulating particles on the gap double-wall conduit 7, which helps to improve the electric-assisted bending accuracy of the gap double-wall conduit 7.

[0050] In some embodiments, the purity of aluminum oxide in the insulating particles is 99%, which has the advantages of high temperature resistance, high pressure resistance, high hardness, and good insulation, and can provide good support for the tube wall of the gap double-walled conduit 7 during the electric-assisted bending of the gap double-walled conduit 7, further improving the electric-assisted bending accuracy of the gap double-walled conduit 7. In addition, the density of the insulating particles with an aluminum oxide purity of 99% is relatively small. When the temperature of the gap double-walled conduit 7 is high, the low-density insulating particles can effectively reduce the possibility of deformation of the bent part of the gap double-walled conduit 7 due to the influence of the gravity of the insulating particles, which helps to improve the bending accuracy of the gap double-walled conduit 7.

[0051] Under the same experimental conditions, based on the above-mentioned electric-assisted bending forming device, two groups of pipe bending experiments were carried out using the same front cover 1, rear cover 2 and wire rope 3. In one group of experiments, insulating particles with a purity of 99% of aluminum oxide were filled in the gap double-walled conduit 7, and in the other group of experiments, insulating particles were not filled in the gap double-walled conduit 7. Based on the experimental results, it can be found that after filling with insulating particles with a purity of 99% of aluminum oxide, the wall thickness thinning rate of the bent part of the gap double-walled conduit 7 can be reduced by more than 60%, reducing the possibility of thin-wall failure of the bent part of the gap double-walled conduit 7; reducing the cross-sectional ellipticity of the bent part of the gap double-walled conduit 7 by 70%, improving the cross-sectional shape accuracy of the bent part of the gap double-walled conduit 7; reducing the rebound angle of the bent part of the gap double-walled conduit 7 by 60% to 70%, reducing the working hours required for the secondary correction of the bent part of the gap double-walled conduit 7; significantly improving the surface quality of the bent part of the gap double-walled conduit 7, and reducing the roughness of the bent part of the gap double-walled conduit 7 by 50%.

[0052] Furthermore, when the particle size of the insulating particles is 1-3 mm, the supporting effect and flow effect of the insulating particles in the gap double-walled conduit 7 are relatively balanced, which can effectively suppress the problem of wall thickness thinning of the gap double-walled conduit 7 after electrically assisted bending.

[0053] When the particle size of the insulating particles is 0.1-1 mm, the filling density of the insulating particles in the gap double-walled conduit 7 is relatively high, and there are more contact points between the insulating particles and the tube wall, which can evenly disperse the tensile stress on the inner side of the tube wall. However, the insulating particles are easily crushed, resulting in partial collapse of the curved part of the gap double-walled conduit 7.

[0054] When the particle size of the insulating particles is greater than 3 mm, the filling density of the insulating particles in the double-wall catheter with gaps 7 is relatively small, the contact points between the insulating particles and the pipe wall are few, and the support for the pipe is not continuous enough, which easily leads to local deformation concentration when the double-wall catheter with gaps 7 is bent, resulting in problems such as an increase in the cross-sectional ellipticity in the bent part of the double-wall catheter with gaps 7.

[0055] Taking a TA18 titanium alloy tube with a diameter of 30 mm and a wall thickness of 1 mm as an example, an electric pulse with a current density of 3 A / mm 2 , a frequency of 20 Hz, and a pulse width of 0.5 ms is applied to this titanium alloy tube, and the titanium alloy tube is bent with parameters of a bending radius of R = 90 mm and a bending angle of 120°. During the bending process, 99 alumina particles with different particle sizes are filled in the titanium alloy tube, and the forming results are shown in Table 1:

[0056] Table 1

[0057] Particle size / mm 0.5 2 5 Wall thickness reduction rate / % 9.5 8.2 11.3 Cross-section ovality / % 5.2 6.8 12.5 Springback angle / ° 5.1 5.8 8.3 Surface roughness / Ra 0.9 1.2 2.0

[0058] In some of the embodiments, the electric-assisted bending forming device further includes: a power supply, which is connected to the end of the steel wire rope 3 far from the front end cover 1 and the outer conductive layer 21. The power supply is not shown in the figure.

[0059] In some of the embodiments, the power supply provides a periodic pulsed current to the double-wall catheter with gaps 7. Since the current is mainly transmitted through the pipe material of the double-wall catheter with gaps 7 itself and the energy is concentrated on the pipe material, a short pulse can be used to increase the heating speed of the pipe material and reduce oxidation. For example, the pulse width of the power supply is less than 1 ms.

[0060] In some of the embodiments, the positive pole of the power supply is connected to the outer conductive layer 21, and the negative pole of the power supply is connected to the steel wire rope 3, so that the outer layer 72 of the double-wall catheter with gaps 7 is preferentially heated to meet the greater plastic deformation requirements of the outer layer 72 when the double-wall catheter with gaps 7 is bent.

[0061] In some of the embodiments, the electric-assisted bending forming device further includes: a spherical bearing 4, which is driven by a driving device to move vertically and horizontally and is connected to the driving device through a bracket 8. The driving device is not shown in the figure.

[0062] A bending ball die 5, which is connected to the inner ring of the spherical bearing 4 and has a pipe forming channel inside.

[0063] A guiding mechanism 6, which is connected to the bending ball die 5 and has a pipe guiding channel communicated with the pipe forming channel inside.

[0064] Among them, the spherical bearing 4, the bending ball die 5, and the guiding mechanism 6 are the basic structures for the three-dimensional electro-assisted bending forming of metal pipes at present. The spherical bearing 4, the bending ball die 5, and the guiding mechanism 6 are all described in Chinese patents CN207615432U and CN216068654U, and will not be elaborated here.

[0065] In some embodiments, the electro-assisted bending forming device further includes: a pressing mechanism 9, disposed on a side of the guiding mechanism 6 away from the bending ball die 5, for annularly clamping the double-wall catheter with a gap 7 to prevent pre-deformation of the double-wall catheter with a gap 7 before entering the guiding mechanism 6.

[0066] In some embodiments, the front end cover 1 is located on a side of the bending ball die 5 away from the guiding mechanism 6, and the rear end cover 2 is located on a side of the guiding mechanism 6 away from the bending ball die 5. The structure of the rear end cover 2 is more complex and heavier than that of the front end cover 1. Setting the rear end cover 2 behind the bending ball die 5 can reduce the possibility that the bent part of the double-wall catheter with a gap 7 is deformed by the gravity of the front end of the double-wall catheter with a gap 7, which helps to improve the forming accuracy of the double-wall catheter with a gap 7.

[0067] The present invention also provides a method for electro-assisted bending forming of a double-wall catheter with a gap, using the above electro-assisted bending forming device to perform bending forming of the double-wall catheter with a gap 7; during the bending forming, one end of the steel wire rope 3 away from the front end cover 1 and the outer conductive layer 21 are both connected to a power source.

[0068] Further, the positive pole of the power source is connected to the outer conductive layer 21, and the negative pole of the power source is connected to the steel wire rope 3.

[0069] Further, the power source provides a periodic pulsed current to the double-wall catheter with a gap 7, and the current parameters are adjustable. The current parameters include current density, frequency, and pulse width.

[0070] Further, the pulse width of the power source is less than 1 ms.

[0071] Further, by fixing the position of the rear end cover 2 relative to the front end cover 1 and tightening the steel wire rope 3, a force towards the rear end cover 2 can be applied to the front end cover 1 to squeeze the insulating particles in the double-wall catheter with a gap 7 and change the pressure inside the double-wall catheter with a gap 7.

[0072] Through the description of multiple embodiments of the electro-assisted bending forming device for the double-wall catheter with a gap of the present invention, it can be seen that the embodiments of the electro-assisted bending forming device for the double-wall catheter with a gap of the present invention have at least one or more of the following advantages:

[0073] 1. Use the electro-assisted bending forming device of the above-mentioned gap double-wall catheter 7 to perform the bending forming of the gap double-wall catheter 7; during the bending forming, one end of the steel wire rope 3 far from the front end cover 1 and the outer conductive layer 21 are both connected to the power supply, so that the inner layer 71 and the outer layer 72 of the gap double-wall catheter 7 form a series circuit, and the connection objects of the positive and negative poles of the power supply are located at the same end of the gap double-wall catheter 7. The required circuit is shorter, which helps to reduce the power consumption of the bending forming of the gap double-wall catheter 7, reduce the possibility of circuit aging and failure caused by local overheating of the circuit, and improve the response accuracy and response speed of the gap double-wall catheter 7 to the adjustment of power supply parameters.

[0074] 2. During the bending process, both the inner layer 71 and the outer layer 72 of the gap double-wall catheter 7 will be supported by the insulating particles, so that the wall thickness change of the bent part of the gap double-wall catheter 7 is uniform, and the gap of the bent part of the gap double-wall catheter 7 is kept uniform. The degree of cross-section distortion of the pipe material will be greatly reduced, and the situations of bending instability and wrinkling and serious wall thickness change will also be improved.

[0075] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same and similar parts between the various embodiments, reference can be made to each other.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or some technical features can be equivalently replaced; without departing from the spirit of the technical solutions of the present invention, they should all be covered by the scope of the technical solutions claimed by the present invention.

Claims

1. Electro-assisted bending forming device for a clearance double-wall catheter, characterized in that, Comprising: A front end cover, which is a conductive structure and is provided with a first front slot for inserting the outer layer of the gap double-wall conduit and a second front slot for inserting the inner layer of the gap double-wall conduit; A rear end cover, comprising: an outer conductive layer, which is provided with a first rear slot for inserting the outer layer of the gap double-wall conduit; an inner conductive layer, which is arranged inside the outer conductive layer and is provided with a second rear slot for inserting the inner layer of the gap double-wall conduit; an insulating layer, which is arranged between the outer conductive layer and the inner conductive layer; A steel wire rope, one end of which is connected to the front end cover, and the other end passes through the rear end cover and is electrically connected to the inner conductive layer and insulated from the outer conductive layer.

2. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 1, wherein, Further comprising: Insulating particles, which are filled inside the inner layer of the gap double-wall conduit and between the two layers of the gap double-wall conduit.

3. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 2, wherein The purity of alumina in the insulating particles is 99%.

4. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 3, characterized in that, The particle size of the insulating particles is 1-3 mm.

5. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 1, characterized in that, Further comprising: A power supply, which is connected to the end of the steel wire rope away from the front end cover and the outer conductive layer.

6. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 5, wherein The positive pole of the power supply is connected to the outer conductive layer, and the negative pole of the power supply is connected to the steel wire rope.

7. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 5, characterized in that, The power supply provides a periodic pulsed current to the gap double-wall conduit; the pulse width of the power supply is less than 1 ms.

8. The electro-assisted bending and forming device for the clearance double-wall catheter according to any one of claims 1-7, characterized in that, Further comprising: A spherical bearing; A bending ball die, which is connected to the inner ring of the spherical bearing and has a pipe forming channel inside; A guiding mechanism, which is connected to the bending ball die and has a pipe guiding channel communicated with the pipe forming channel inside.

9. The electro-assisted bending and forming device for the clearance double-wall catheter according to claim 8, characterized in that, The front end cover is located on the side of the bending ball die away from the guiding mechanism, and the rear end cover is located on the side of the guiding mechanism away from the bending ball die.

10. Electro-assisted bending forming method for a gap double-wall catheter, characterized in that: Using the electro-assisted bending forming device for the gap double-wall conduit according to any one of claims 1-9 to perform the bending forming of the gap double-wall conduit; during the bending forming, the end of the steel wire rope away from the front end cover and the outer conductive layer are both connected to the power supply.

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