阅读说明：本技术 一种易于拆卸的弯管防皱芯棒 (Elbow crease-resistant core rod easy to disassemble ) 是由 章凯羽 汪云徽 王纯贤 吴喆 张润桐 于 2020-07-22 设计创作，主要内容包括：本发明公开了一种易于拆卸的弯管防皱芯棒,包括限位芯线、多个芯棒元和限位圆珠,限位芯线串联各个芯棒元和限位圆珠,每个芯棒元中分别设有多个绕穿孔,多个绕穿孔呈环向分布,多个芯棒元的对应绕穿孔构成抽芯通道；每个芯棒元中多个绕穿孔两两一组,抽芯线一一对应绕穿孔分组,每个抽芯线一端约束于绕穿孔分组中的第一个绕穿孔一端,另一端穿过第一个绕穿孔,然后绕过芯棒元后再反向穿过对应绕穿孔分组的第二个绕穿孔,接着抽芯线另一端再依次穿过其他芯棒元对应位置的绕穿孔构成的抽芯通道部分,由从同一抽芯通道穿过的多个抽芯线合为一束分别形成抽芯线束。本发明实现了柔性芯棒抽芯过程保护管壁的功能。(The invention discloses an easily-detachable anti-crease core rod for a bent pipe, which comprises a limiting core wire, a plurality of core rod elements and a limiting ball, wherein the limiting core wire is connected with each core rod element and the limiting ball in series; every two of a plurality of holes of twining in every core rod unit are a set of, the line of loosing core one-to-one corresponds the hole of loosing core and divides into groups, every line of loosing core one end restraint in around the first hole of loosing core one end in the hole group, the other end passes first hole of loosing core, then after the core rod unit reverse pass corresponding around the second hole of loosing core that the hole was divided into groups again, the line other end of loosing core again passes the passageway part of loosing core that the hole of loosing core corresponded to other core rod units constitutes in proper order, by a plurality of core wires that pass from same passageway of loosing core close into a bunch and form the pencil of. The invention realizes the function of protecting the tube wall in the core pulling process of the flexible core rod.)

1. The utility model provides an easy return bend crease-resistance plug of dismantling, including spacing heart yearn, a plurality of plug components, a plurality of spacing ball, every plug component center is equipped with respectively along the perforation that the first axial of institute's core rod link up, every spacing ball center is equipped with the through-hole respectively, a plurality of plug components are arranged in proper order, the interval sets up the same at least one spacing ball of quantity between the adjacent plug component, spacing heart yearn passes the perforation of each plug component and the through-hole of each spacing ball, establish ties each plug component and spacing ball by spacing heart yearn, its characterized in that: each core rod element is provided with a plurality of winding through holes with the same quantity, the winding through holes are axially parallel to the axial direction of the core rod element and penetrate through the core rod element, the plurality of winding through holes are annularly distributed by taking the center of the core rod element as the center of a circle, the winding through holes of the plurality of core rod elements are in one-to-one correspondence, and the winding through holes in the plurality of core rod elements with corresponding positions form a core pulling channel;

the plurality of winding through holes in each core rod element are grouped into a plurality of winding through hole groups in a pairwise manner along the circumferential direction, each core rod element is also provided with a core pulling wire which corresponds to the plurality of winding through hole groups one by one, one end of each core pulling wire is constrained at one end of the first winding through hole in the corresponding winding through hole group, the other end of each core pulling wire penetrates through the corresponding winding through hole group to form the first winding through hole, then bypassing the core rod element position between two winding through holes in the corresponding winding through hole group and then reversely passing through the second winding through hole of the corresponding winding through hole group, then the other end of the core pulling line sequentially passes through the core pulling channel part formed by the winding through holes at the corresponding positions of other core rod elements in the direction of penetrating out of the second winding through hole, and the directions of the plurality of core pulling wires penetrating through the same core pulling channel are the same, and the plurality of core pulling wires penetrating through the same core pulling channel are combined into a bundle to form a core pulling wire bundle respectively.

2. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: in each core rod element, one end of each core pulling wire is constrained at one end of a first winding through hole in a corresponding winding through hole group, one end of a part of the core pulling wire is constrained at one end of the first winding through hole in the same direction, one end of the other core pulling wire is constrained at one end of the first winding through hole in the other direction, the other end of each core pulling wire penetrates through the first winding through hole in the corresponding winding through hole group, then the core pulling wire bypasses the position of the core rod element between the two winding through holes in the corresponding winding through hole group and then reversely penetrates through the second winding through hole in the corresponding winding through hole group, then the other end of the limiting core wire sequentially penetrates through a core pulling channel part formed by the winding through holes in the corresponding positions of the other core rod elements in the winding through hole penetrating direction from the second winding through hole, the directions of the core pulling wires penetrating through the same core pulling channel are the same, and the core pulling wires penetrating through the same core pulling channel are combined into, in the multiple core pulling wire bundles obtained in the way, part of the core pulling wire bundles respectively penetrate out of the corresponding core pulling channels along the same direction, and the rest of the core pulling wire bundles respectively penetrate out of the corresponding core pulling channels along the other direction, so that an A-shaped core pulling wire winding-through structure is formed.

3. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: in each core rod element, one end of each core pulling wire is constrained to one end, in the same direction, of a first winding through hole in a corresponding winding through hole group, the other end of each core pulling wire penetrates through the first winding through hole in the corresponding winding through hole group, then the core rod element between two winding through holes in the corresponding winding through hole group reversely penetrates through a second winding through hole after bypassing, the other end of each core pulling wire sequentially penetrates through a core pulling channel part formed by winding through holes in corresponding positions of other core rod elements in the direction of penetrating out of the second winding through hole, the directions of the core pulling wires penetrating through the same core pulling channel are the same, a plurality of core pulling wires penetrating through the same core pulling channel are combined into a bundle to form core pulling wire bundles, and the obtained core pulling wire bundles respectively penetrate through the corresponding core pulling channels in the same direction to form a core pulling wire B-type winding through structure.

4. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: each core rod element is a flat cylinder, the diameter of the flat cylinder is smaller than that of the bent pipe, and the edges of the round surfaces at the two axial ends of the flat cylinder are respectively set to be round corners.

5. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: the diameter of the limiting ball is larger than the diameter of the through hole at the center of the core rod element.

6. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: the diameter of the through hole at the center of the core rod element is larger than that of the through hole at the center of the limiting ball.

7. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: the limiting core wire and the core drawing wire are made of high-elasticity fibers and have certain toughness.

8. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: the core pulling device is characterized in that a node is arranged at one end of the core pulling line, the diameter of the node is larger than that of the winding through hole, the node at one end of the core pulling line is arranged on the surface of the core rod element at the position corresponding to one end of a first winding through hole in the corresponding winding through hole group, and therefore one end of the core pulling line is constrained at one end of the first winding through hole.

9. The easy-to-disassemble crease-resistant mandrel for bent pipes according to claim 1, characterized in that: the two ends of the limiting core wire are respectively provided with a detachable node, the diameter of the node is larger than the aperture of the through hole at the center of the limiting ball, the nodes are respectively positioned at the two ends of the series structure formed by the core rod element and the limiting ball, and the limiting core wire node can be pulled and pulled by removing the limiting core wire node through the series structure formed by the node limiting core rod element and the limiting ball.

Technical Field

The invention relates to the field of bend pipe crease-resistant core rods, in particular to a bend pipe crease-resistant core rod easy to disassemble.

Background

With the continuous progress and development of social science and technology, the elbow technology is more applied to equipment such as ships, aircraft engines and nuclear reactors, and the requirements on pipe fitting forming and performance are more strict. The bending radius is smaller and the wall thickness of the pipe is thinner and thinner, so that the forming defect is more easily generated. The anti-crease die is an effective means for reducing the bending forming defects of the pipe fittings, but the pipe fittings are easy to wear when the anti-crease die is taken out due to the radial deformation of the pipe fittings after the pipe fittings are bent, so that the forming quality is reduced. When the pipe fitting is bent, the bend pipe crease-resistant core rod easy to loose core is suitable for the pipe fitting with small bending radius and thin pipe fitting wall thickness, and the forming quality of the bend pipe is improved. Therefore, the core rod structure is improved to meet the requirements of the bent pipe with small bending radius and thin pipe wall thickness, and the method has important significance in the manufacturing process of bent pipe parts.

The existing core rods can be divided into a hard core rod (a column-type core rod) and a flexible core rod (a universal joint core rod and a multi-ball-head core rod) according to a constraint form. In the process of stretch-wrap bending, the rigid core rod has higher requirements on the position between the core rod and a bending point, the reduction rate of the pipe wall can be increased when the working end of the core rod enters a bending section too long, and the ovality can be increased when the working end of the core rod does not extend enough; due to the movable structural characteristics of the flexible core rod, compared with a rigid core rod, the flexible core rod can strongly support the deformation position of the pipe fitting in the bending process of the pipe fitting, so that the defects generated in the bending process of the pipe fitting are overcome.

The existing flexible core rod structure is as shown in chinese patent with application number 201910968121.8: a variable-diameter crease-resistant mandrel for elbow pipe is composed of a flexible mandrel structure consisting of multiple mandrel units and small balls, which are serially connected via core wires. When the flexible core rod structure is used for processing a pipe fitting with a small bending radius and a thin pipe fitting wall, because the posture of the core rod element in the bent pipe cannot be adjusted, the contact area of the core rod element and the inner wall of the bent pipe cannot be adjusted, the problem of difficult core pulling is caused, and the pipe wall is abraded if the core pulling is forcibly performed.

Disclosure of Invention

The invention aims to provide an easily-detachable bend pipe crease-resistant core rod, and aims to solve the problems that a flexible core rod in the prior art is difficult to loose core and easy to abrade a pipe wall.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the utility model provides an easy return bend crease-resistance plug of dismantling, including spacing heart yearn, a plurality of plug components, a plurality of spacing ball, every plug component center is equipped with respectively along the perforation that the first axial of institute's core rod link up, every spacing ball center is equipped with the through-hole respectively, a plurality of plug components are arranged in proper order, the interval sets up the same at least one spacing ball of quantity between the adjacent plug component, spacing heart yearn passes the perforation of each plug component and the through-hole of each spacing ball, establish ties each plug component and spacing ball by spacing heart yearn, its characterized in that: each core rod element is provided with a plurality of winding through holes with the same quantity, the winding through holes are axially parallel to the axial direction of the core rod element and penetrate through the core rod element, the plurality of winding through holes are annularly distributed by taking the center of the core rod element as the center of a circle, the winding through holes of the plurality of core rod elements are in one-to-one correspondence, and the winding through holes in the plurality of core rod elements with corresponding positions form a core pulling channel;

the plurality of winding through holes in each core rod element are grouped into a plurality of winding through hole groups in a pairwise manner along the circumferential direction, each core rod element is also provided with a core pulling wire which corresponds to the plurality of winding through hole groups one by one, one end of each core pulling wire is constrained at one end of the first winding through hole in the corresponding winding through hole group, the other end of each core pulling wire penetrates through the corresponding winding through hole group to form the first winding through hole, then bypassing the core rod element position between two winding through holes in the corresponding winding through hole group and then reversely passing through the second winding through hole of the corresponding winding through hole group, then the other end of the core pulling line sequentially passes through the core pulling channel part formed by the winding through holes at the corresponding positions of other core rod elements in the direction of penetrating out of the second winding through hole, and the directions of the plurality of core pulling wires penetrating through the same core pulling channel are the same, and the plurality of core pulling wires penetrating through the same core pulling channel are combined into a bundle to form a core pulling wire bundle respectively.

An easy return bend crease-resistance plug of dismantling, its characterized in that: in each core rod element, one end of each core pulling wire is constrained at one end of a first winding through hole in a corresponding winding through hole group, one end of a part of the core pulling wire is constrained at one end of the first winding through hole in the same direction, one end of the other core pulling wire is constrained at one end of the first winding through hole in the other direction, the other end of each core pulling wire penetrates through the first winding through hole in the corresponding winding through hole group, then the core pulling wire bypasses the position of the core rod element between the two winding through holes in the corresponding winding through hole group and then reversely penetrates through the second winding through hole in the corresponding winding through hole group, then the other end of the limiting core wire sequentially penetrates through a core pulling channel part formed by the winding through holes in the corresponding positions of the other core rod elements in the winding through hole penetrating direction from the second winding through hole, the directions of the core pulling wires penetrating through the same core pulling channel are the same, and the core pulling wires penetrating through the same core pulling channel are combined into, in the multiple core pulling wire bundles obtained in the way, part of the core pulling wire bundles respectively penetrate out of the corresponding core pulling channels along the same direction, and the rest of the core pulling wire bundles respectively penetrate out of the corresponding core pulling channels along the other direction, so that an A-shaped core pulling wire winding-through structure is formed.

An easy return bend crease-resistance plug of dismantling, its characterized in that: in each core rod element, one end of each core pulling wire is constrained to one end, in the same direction, of a first winding through hole in a corresponding winding through hole group, the other end of each core pulling wire penetrates through the first winding through hole in the corresponding winding through hole group, then the core rod element between two winding through holes in the corresponding winding through hole group reversely penetrates through a second winding through hole after bypassing, the other end of each core pulling wire sequentially penetrates through a core pulling channel part formed by winding through holes in corresponding positions of other core rod elements in the direction of penetrating out of the second winding through hole, the directions of the core pulling wires penetrating through the same core pulling channel are the same, a plurality of core pulling wires penetrating through the same core pulling channel are combined into a bundle to form core pulling wire bundles, and the obtained core pulling wire bundles respectively penetrate through the corresponding core pulling channels in the same direction to form a core pulling wire B-type winding through structure.

An easy return bend crease-resistance plug of dismantling, its characterized in that: each core rod element is a flat cylinder, the diameter of the flat cylinder is smaller than that of the bent pipe, and the edges of the round surfaces at the two axial ends of the flat cylinder are respectively set to be round corners.

An easy return bend crease-resistance plug of dismantling, its characterized in that: the diameter of the limiting ball is larger than the diameter of the through hole at the center of the core rod element.

An easy return bend crease-resistance plug of dismantling, its characterized in that: the diameter of the through hole at the center of the core rod element is larger than that of the through hole at the center of the limiting ball.

An easy return bend crease-resistance plug of dismantling, its characterized in that: the limiting core wire and the core drawing wire are made of high-elasticity fibers and have certain toughness.

An easy return bend crease-resistance plug of dismantling, its characterized in that: the core pulling device is characterized in that a node is arranged at one end of the core pulling line, the diameter of the node is larger than that of the winding through hole, the node at one end of the core pulling line is arranged on the surface of the core rod element at the position corresponding to one end of a first winding through hole in the corresponding winding through hole group, and therefore one end of the core pulling line is constrained at one end of the first winding through hole.

An easy return bend crease-resistance plug of dismantling, its characterized in that: the two ends of the limiting core wire are respectively provided with a detachable node, the diameter of the node is larger than the aperture of the through hole at the center of the limiting ball, the nodes are respectively positioned at the two ends of the series structure formed by the core rod element and the limiting ball, and the limiting core wire node can be pulled and pulled by removing the limiting core wire node through the series structure formed by the node limiting core rod element and the limiting ball.

The core pulling wires penetrate through the corresponding core pulling channels respectively to be connected with the core rod elements in series, the core rod elements are integrally placed in the bent pipe when the bent pipe is machined, the core rod elements can be inclined by pulling one end of the core pulling wire, which penetrates out of the core pulling channel, at the corresponding position, and the core rod elements can be inclined in different directions through a plurality of groups of core pulling wires, which penetrate out of the core pulling channels from different positions, so that the postures of the core rod elements in the bent pipe can be adjusted when the bent pipe is machined, the contact area of the core rod elements and the inner wall of the bent pipe is further reduced.

According to the invention, the diameter of the radial section of the core rod element is slightly smaller than the inner diameter of the bent pipe, and the core rod element has a certain thickness and has a certain supporting effect on the bent pipe.

In the invention, the diameter of the through hole at the center of the core rod element is larger than that of the through hole at the center of the limiting ball, so that the core rod element can be regulated to a certain extent in rotation. The distance between adjacent core rods is adjusted by using the diameter and the number of the limiting round balls, so that the minimum bending radius of the core rods can be changed.

In the invention, the limiting core wire and the winding core wire are made of high-elasticity fibers and are not easy to break in the bending process, the diameter of the winding core wire is slightly smaller than that of the core winding through hole, and the diameter of the limiting core wire is slightly smaller than that of the limiting ball through hole.

Compared with the prior art, the invention provides the bend pipe crease-resistant core rod easy for core pulling, the function of protecting the pipe wall in the core pulling process of the flexible core rod is realized, the core rod structure is simplified, and the cost for manufacturing the bend pipe is reduced; the core pulling process is easier, and the core pulling device has a good protection effect.

Drawings

Fig. 1 is a schematic structural diagram of an easy core-pulling bend anti-wrinkling core rod A-shaped winding-through structure.

FIG. 2 is a schematic structural view of a B-shaped winding-through of a core rod of a bend pipe with easy core-pulling for preventing crease of core rod

Fig. 3 is a schematic structural view of the core rod element of the present invention.

FIG. 4 is a schematic view of a limiting ball structure of the present invention.

Fig. 5 is a schematic structural view of an a-type through-winding core rod element of the present invention.

FIG. 6 is a schematic structural diagram of a B-type through-winding core rod element of the present invention.

FIG. 7 is a schematic view of a bundle of loose wires according to the present invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in fig. 1 and fig. 2, the easy-to-detach crease-resistant mandrel for bending pipe of the present invention includes a limiting core wire 1, a plurality of mandrel elements 2, and a plurality of limiting beads 3, and in the present embodiment, six mandrel elements 2 and seven limiting beads 3 are used for description.

As shown in fig. 3 and 4, a through hole 7 axially penetrating through each mandrel element 2 is formed in the center of each mandrel element 2, a through hole 8 is formed in the center of each limiting ball 3, six mandrel elements 2 are sequentially arranged, the same number of limiting balls 3 are arranged between adjacent mandrel elements 2 at intervals, and the number of limiting balls 3 between adjacent mandrel elements 2 is one in the embodiment. The total number of the limiting round balls 3 clamped between the core rod elements 2 is five, and the other two limiting round balls are positioned at two ends of the sequentially arranged structure of the core rod elements 2.

The limiting core wire 1 passes through the through hole 7 of each core rod element 2 and the through hole 8 of each limiting ball 3, and each core rod element 2 and each limiting ball 3 are connected in series by the limiting core wire 1.

Each core rod element 2 is a flat cylinder, the diameter of the flat cylinder is smaller than that of the bent pipe, and the edges of the round surfaces at the two axial ends of the flat cylinder are respectively set to be round corners.

In the invention, the diameter of the limiting ball 3 is larger than the perforation diameter of the center of the core rod element 2. The diameter of a through hole 7 at the center of the core rod element 2 is larger than that of a through hole 8 at the center of the limiting ball 3.

As shown in fig. 1, 2, and 3, each mandrel element 2 is provided with a plurality of winding through holes 6, and each mandrel element 2 in this embodiment is provided with four winding through holes 6.11, 6.12, 6.21, and 6.22. The axial directions of the through holes 6.11, 6.12, 6.21 and 6.22 are all parallel to the axial direction of the core rod element 2 and penetrate through the core rod element 2, the four through holes 6.11, 6.12, 6.21 and 6.22 are annularly and uniformly distributed by taking the center of the core rod element 2 as a circle center, and specifically, the four through holes 6.11, 6.12, 6.21 and 6.22 are sequentially and uniformly distributed along the anticlockwise annular direction. The through-winding holes of the six core rod elements 2 correspond to one another in position, that is, the through-winding holes 6.11 of each core rod element 2 correspond to one another in position, the through-winding holes 6.12 correspond to one another in position, the through-winding holes 6.21 correspond to one another in position, and the through-winding holes 6.22 correspond to one another in position, so that the through-winding holes in the six core rod elements 2 form a core-pulling channel, that is, the through-winding holes 6.11 of each core rod element 2 form a core-pulling channel, the through-winding holes 6.12 of each core rod element 2 form a core-pulling channel, the through-winding holes 6.21 of each core rod element 2 form a core-pulling channel, and the through-winding holes 6.22 of each core rod element 2 form a core-pulling.

As shown in fig. 5, 6 and 7, the four through-holes in each mandrel element 2 are grouped into a plurality of through-hole groups two by two in the circumferential direction, in this embodiment, the through-holes 6.11 and 6.12 in each mandrel element 2 form a first through-hole group, and the through-holes 6.21 and 6.22 form a second through-hole group. Each core rod element 2 is also provided with a drawing wire 5, which in this embodiment is provided with drawing wires 5.1 and 5.2 in groups corresponding to two winding perforations.

As shown in fig. 1 and 5, one end of the cored wire 5.1 is constrained to the axial front end of the winding through hole 6.11 in the first winding through hole group of the mandrel element 2, a node 9 is arranged at one end of the cored wire 5.1, the diameter of the node 9 is larger than that of the winding through hole, and the node 9 is located on the front side surface of the mandrel element 2 corresponding to the axial front end of the winding through hole 6.11, so that one end of the cored wire 5.1 is constrained to the axial front end of the winding through hole 6.11. The other end of the core pulling wire 5.1 passes through the winding through holes 6.11 in the first winding through hole group backwards, then obliquely downwards passes through the winding through holes 6.12 of the first winding through hole group backwards and forwards after passing through the positions of the core rod elements between the two winding through holes in the first winding through hole group backwards, and then the other end of the core pulling wire 5.1 sequentially passes through the core pulling channel part formed by the winding through holes 6.12 at the corresponding positions of other core rod elements in the front in the penetrating direction from the winding through holes 6.12.

In the invention, the core-pulling lines 5.1 in different core rod elements 2 enter the core-pulling channels formed by the winding through holes 6.12 corresponding to the respective positions from different positions. Namely, the other end of the core pulling wire 5.1 of the first core rod element forwards passes through the core pulling channel part formed by the winding through hole 6.12 of the first core rod element; the other end of the core pulling wire 5.1 of the second core rod element forwards passes through a core pulling channel part formed by the second core rod element winding through hole 6.12 and then forwards passes through the first core rod element winding through hole 6.12; the other end of the core pulling wire 5.1 of the third core rod element forwards passes through a winding through hole 6.12 of the third core rod element, then forwards passes through a winding through hole 6.12 of the second core rod element and continues to forwards pass through a winding through hole 6.12 of the first core rod element; and so on, finally, the other end of the core pulling wire 5.1 of each core rod element 2 passes through the core pulling channel formed by the winding through hole 6.12 forwards, but the position of the core pulling channel is different, and the distance of the passing core pulling channel is also different. The direction of the core pulling wire 5.1 of each core rod element 2 passing through the core pulling channel formed by the winding through holes 6.12 is the same (namely, the forward direction). Thus, a plurality of core pulling wires 5.1 passing through the same core pulling channel formed by the winding through holes 6.12 are combined into a bundle to form the core pulling wire bundle 4.1 respectively.

As shown in fig. 1 and 5, one end of the core pulling wire 5.2 is constrained to the axial rear end of the winding through hole 6.21 in the second winding through hole group of the core rod element 2, and a node is also arranged at one end of the core pulling wire 5.2, and the node is located on the rear side surface of the core rod element 2 corresponding to the axial rear end of the winding through hole 6.21, so that one end of the core pulling wire 5.2 is constrained to the axial front end of the winding through hole 6.21. The other end of the core pulling wire 5.2 passes through the winding through holes 6.21 in the second winding through hole group forwards, then passes through the winding through holes 6.22 of the second winding through hole group backwards and backwards after obliquely passing through the positions of the core rod elements between the two winding through holes in the second winding through hole group backwards, and then the other end of the core pulling wire 5.2 sequentially passes through the core pulling channel part formed by the winding through holes 6.22 at the corresponding positions of other core rod elements in the direction of passing out of the winding through holes 6.22, namely the back.

Similarly, the core-pulling lines 5.2 in different core rod elements 2 enter the core-pulling channels formed by the winding through holes 6.22 corresponding to the respective positions from different positions, and the core-pulling channels are introduced into different positions and have different distances. The direction of the core pulling wire 5.2 of each core rod element 2 passing through the core pulling channel formed by the winding through holes 6.22 is the same (namely, backward). The plurality of core wires 5.2 which thus pass through the same core passage formed around the through-hole 6.22 are combined into a bundle to form the core bundle 4.2. At this time, the end of the core bundle 4.1 is directed forward, the end of the core bundle 4.2 is directed backward, and the directions of the two are different, thereby constituting a core bundle a-type wire-wrapping structure.

As shown in fig. 2 and 6, in this embodiment, one end of the core pulling wire 5.2 is constrained to the axial front end of the through winding hole 6.22 in the second through winding hole group of the core rod element 2, and a node is also provided at one end of the core pulling wire 5.2, and the node is located on the front side surface of the core rod element 2 corresponding to the axial front end of the through winding hole 6.22, so that one end of the core pulling wire 5.2 is constrained to the axial front end of the through winding hole 6.22. The other end of the core pulling wire 5.2 passes through the winding through hole 6.22 in the second winding through hole group backwards, then passes through the other winding through hole 6.21 in the second winding through hole group backwards and forwards after obliquely passing through the position of the core rod element between the two winding through holes in the second winding through hole group downwards, and then passes through the core pulling channel part formed by the winding through holes 6.21 at the corresponding positions of the other core rod elements in the front in the direction of passing out from the winding through hole 6.21 sequentially from the other end of the core pulling wire 5.2. The core bundles 4.2 are thus formed by combining a plurality of core wires 5.2, which have been threaded through the same core passage formed around the through-hole 6.21, into one bundle. At this time, the end of the core bundle 4.1 is advanced, the end of the core bundle 4.2 is also advanced, and both directions are the same, thereby forming a core bundle B-type wire-wrapping structure.

In the invention, the material of the limiting core wire 1 and the drawing core wire 5 is high-elasticity fiber and has certain toughness.

According to the invention, two ends of a limiting core wire 1 are respectively provided with a detachable node, the diameter of the node is larger than the aperture of a through hole in the center of a limiting ball 3, the nodes are respectively positioned at two ends of a series structure formed by a core rod element 2 and the limiting ball 3, and the limiting core wire node can be pulled by removing the limiting core wire node through the series structure formed by the node limiting core rod element 2 and the limiting ball 3.

In the invention, the core rod element 2 is driven to incline by pulling the core pulling wire harness 4 consisting of the core pulling wire 5, thereby reducing the contact area of the core rod element 2 and the inner wall of the bent pipe and realizing the simple disassembly of the crease-resistant core rod of the bent pipe.

The embodiments of the present invention are described only for the preferred embodiments of the present invention, and not for the limitation of the concept and scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the design concept of the present invention shall fall into the protection scope of the present invention, and the technical content of the present invention which is claimed is fully set forth in the claims.