JP2016078089A - Elbow manufacturing device and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elbow manufacturing device capable of restraining thinning and thickening of a bending part.SOLUTION: An elbow manufacturing device comprises a bending roll 1 for bending a processed pipe P, a pair of movable pressures 2 and 2 for pressing the processed pipe P to the bending roll 1 by moving in the contrary circumferential directions N1 and N2 while slidingly contacting with the bending roll 1 and core metal of a divided structure separably constituted into three, integrated in a rod shape and inserted into the processed pipe P, and the core metal is composed of a pair of separate core members 32 and 32 respectively interlocked with-connected to the pair of movable pressures 2 and 2 and slidingly contacting with an inner peripheral surface Pd of the processed pipe P while mutually separating so as to draw a circular arc-shaped locus by moving the movable pressures 2 and 2 in the contrary circumferential directions N1 and N2 and a central core member 31 arranged between the pair of separate core members 32 and 32, and the respective separate core members 32 and 32 comprise a circular arc-shaped guide hole part 53, and the central core member 31 comprises a pair of circular arc-shaped arm parts 61 and 61 slidably inserted into the circular arc-shaped guide hole part 53 and a pipe flatness checking boss part 62.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an elbow manufacturing apparatus and a manufacturing method.

  Conventionally, an elbow manufacturing apparatus is provided integrally with a clamp for holding one end of a pipe to be processed, a bending roll for bending the pipe to a predetermined radius of curvature while the clamp slides on the outer peripheral surface, and a bending roll. A pipe bender device having a pressure for pressing the pipe to be processed against the wiper and a mandrel inserted into the pipe to be processed is used to clamp one end of the pipe to be processed and Press the other end against the wiper with a pressure, insert a mandrel into the pipe to be processed, and then slide the clamp along the outer peripheral surface of the bending roll to bend the pipe to be processed along the bending roll. Devices and methods for producing elbows by deformation are known.

JP 2010-162557 A

However, since the core bar can only be inserted to the front side of the bent part of the pipe to be processed, the radially outer side (outer bent part) of the bent part is subjected to tensile stress and thinning or flattening occurs. There was a problem. In addition, there is a problem in that thickening and wrinkles occur on the radially inner side (inner bent portion) of the bent portion.
In addition, in consideration of thinning, it is necessary to use a specially-processed pipe having a wall thickness dimension larger than that of the finished product, which causes a problem of being uneconomical.

  Then, an object of this invention is to provide the elbow manufacturing apparatus and manufacturing method which can suppress the thickness reduction and thickness increase of a bending part.

  In order to achieve the above object, an elbow manufacturing apparatus of the present invention includes a bending roll for bending a pipe to be processed, and a circumferential direction opposite to the bending roll while sliding the pipe to be processed. A pair of movable pressures to be pressed, and a cored bar having a split structure that is configured to be separable into three parts and is integrated into a rod shape and inserted into the pipe to be processed. A pair of separating core members that are linked and linked to the movable pressure, and are slidably contacted with the inner peripheral surface of the pipe to be machined while being separated from each other so as to draw an arcuate trajectory by moving the movable pressure in opposite directions. And a central core member disposed between the pair of separation core members, each of the separation core members has an arcuate guide hole portion, and the central core member includes the arcuate guide hole. Slidably inserted into the part In which and a pair of arcuate arm portion and the pipe flat blocking boss.

  The elbow manufacturing method of the present invention includes a cored bar insertion step of inserting a cored bar having a split structure for preventing flattening into the pipe to be processed, and a bending process of pressing the pipe to be processed along a bending roll. And the core metal includes a central core member and a pair of separation core members disposed on both sides of the central core member, and is configured to be separable into three, the core metal insertion step The center core member and the pair of separation core members are integrated into a rod shape and inserted into the pipe to be processed, and when bending the pipe to be processed in the bending step, the pair of separation core members are A method in which the center core member stays at the inner center position of the pipe to be processed and prevents flattening of the pipe while being slidably contacted with the inner peripheral surface of the pipe to be processed while being separated from each other so as to draw an arcuate locus. is there.

  According to the present invention, an elbow can be manufactured from a commercially available pipe (in accordance with JIS standards) having an outer diameter (inner diameter) or a wall thickness that is the same as or close to the elbow to be molded. It can produce elbows with seamless and seamless wall thickness such as welding. It is possible to suppress a decrease in thickness on the radially outer side (outer bent portion) of the bent portion and an increase in thickness on the radially inner side (inner bent portion) of the bent portion when the pipe to be processed is bent. A straight pipe compliant with the JIS standard can be bent while keeping it within the thickness tolerance of the JIS standard (within minus 12.5% of the specified thickness). It is possible to suppress the occurrence of flatness, crushing, cracks, cracks and wrinkles at the bent part, reduce the occurrence of defective products, and stably and efficiently manufacture high-quality elbows. A clamping device for gripping the pipe to be processed is not required, and the apparatus can be simplified. In addition, a clamping fee is not required for the pipe to be processed, and the material can be used efficiently (good yield). It can be easily manufactured without skilled skills (experience).

It is a front view which shows an example of the to-be-processed pipe shape | molded by an elbow. It is a front view which shows an example of the elbow which should be shape | molded. It is a half-cut front view of the elbow manufacturing apparatus of this invention which shows embodiment of a bending preparation state. It is a general view which shows the pipe acceptance preparation state of a bending roll and a movable pressure, Comprising: (a) is a half cut front view, (b) is AA sectional drawing of (a). It is a general view which shows an example of a bending roll, Comprising: (a) is a front view, (b) is a side view. It is a general view which shows an example of a movable pressure, Comprising: (a) is a front view, (b) is a side view. It is a general view which shows an example of a metal core, Comprising: (a) is a half cut front view of an integrated state, (b) is BB sectional drawing of (a). It is a general view which shows an example of a center core member, (a) is a top view, (b) is a front view, (c) is CC sectional drawing of (b), (d) Is a bottom view. It is a general view which shows an example of a separation core member, Comprising: (a) is a top view, (b) is a front view, (c) is a side view, (d) is D- of (b). It is D sectional drawing, (e) is EE sectional drawing of (b). It is a half-cut cross-sectional front view in the middle of molding. It is a half-cut cross-sectional front view of a shaping | molding completion state. It is a half-cut cross-sectional front view of a bending process completion state. It is a front view which shows an example of a drive means, (a) is a front view of a bending preparation state, (b) is a front view of a bending process completion state.

Hereinafter, the elbow manufacturing apparatus and method of the present invention will be described in detail based on the illustrated embodiment.
As shown in FIG. 2, the pipe P to be processed having a trapezoidal shape as shown by a solid line in FIG. 1 has a predetermined bending angle θ (so that the pipe axis Lp has a predetermined radius of curvature R3). ) Device and method for making a curved elbow E.
For ease of explanation, the center point of the bending angle θ is called a processing and design reference center point O, and a line that includes the reference center point O and bisects the predetermined bending angle θ is referred to as a processing and design reference center line S. Call. The reference center line S coincides with the horizontal center line of the elbow E. Further, in the bent portion of the elbow E to be formed, a portion on the reference center point O side (radial inward side) from the pipe axis Lp is referred to as an inner bent portion Ea, and the side away from the reference center point O (radial) The outward side) is referred to as an outer bent portion Eb.

First, the elbow manufacturing apparatus of the present invention will be described.
As shown in FIG. 3, a bending roll 1 for bending the work pipe P, and a pair of movable pressures 2 that press the work pipe P along the bending roll 1 while being in sliding contact with the outer peripheral surface 11 of the bending roll 1. , 2 and a cored bar 3 inserted through the pipe P to be processed.

4 and 5, the bending roll 1 includes an outer peripheral surface 11 having a reference center point O as a central point, and a guide groove 12 having a semicircular cross-section that is recessed radially inward from the outer peripheral surface 11. ,have.
The outer peripheral surface 11 is formed with a roll outer peripheral radius of curvature R11 equivalent to the axial center radius of curvature R3 of the elbow E (see FIG. 2).
The guide groove 12 has a groove bottom 12a having a roll groove radius of curvature R12 set equal to the inner radius of curvature of the elbow E to be molded R1 (see FIG. 2) in front view.
The groove width dimension W12 of the guide groove 12 is set to be equal to the pipe outer diameter dimension Dp (see FIG. 2) of the pipe P to be processed. The groove depth dimension H12 of the guide groove 12 is set to be equal to the radial dimension of the pipe P to be processed.

The pair of movable pressures 2 and 2 have end surfaces 21 and 21 which face each other and come into contact with each other in the pipe receiving preparation state of the bending roll 1 and the movable pressure 2 shown in FIG.
4 and 6, it has a through hole 23 that penetrates from one end surface 21 to the other end surface 22 and that can be inserted and removed freely by sliding the pipe P to be processed.
The inner diameter d21 of the through hole 23 is set to be equal to the outer diameter Dp of the pipe, and is provided so as to restrain the pipe P to be processed from expanding.

The movable pressure 2 has a curved slidable contact surface 24 having a circular arc shape when viewed from the front side toward the other end surface 22 side from the intersection Q where the hole axis L2 and the one end surface 21 intersect on the one end surface side. doing.
The slidable contact curvature radius R24 of the curved slidable contact surface 24 is set to be equal to the roll outer peripheral curvature radius R11.
The pressure lateral dimension Y2 of the movable pressure 2 is set to be larger than half the pipe lateral dimension Yp of the processed pipe P.

In the pipe receiving preparation state shown in FIG. 4 and the bending preparation preparation state shown in FIG. 3, the curved sliding contact surfaces 24, 24 of the pair of movable pressures 2, 2 are arranged to face each other and the outer periphery of the bending roll 1. The one end surfaces 21 and 21 are in contact with each other and the through holes 23 and 23 communicate with each other in a straight shape, and the hole axis L2 is disposed on the tangent line of the outer peripheral surface 11 in a front view. (The distance from the reference center point O to the hole axis L2 coincides with the roll outer radius of curvature R11).
Further, the one end surfaces 21 and 21 of the pair of movable pressures 2 are disposed on a reference center line (roll lateral direction center line) S.
The pair of movable pressures 2 and 2 are slidable along the outer peripheral surface 11 in the circumferential directions N1 and N2 opposite to the reference center line S (of the bending roll 1).

Next, as shown in FIG. 3, the core metal 3 includes a center core member 31 and a pair of separation core members 32 and 32 disposed on both sides of the center core member 31 and can be separated into three. It is configured in such a divided structure and is integrated into a single rod shape, and is inserted through the processed pipe P and the through holes 23, 23 of the pair of movable pressures 2,2.
The horizontal dimension Y3 of the metal core 3 is set longer than the horizontal dimension Yp of the pipe and longer than twice the horizontal dimension Y2 of the pressure. The other end 32b of 32 is provided so as to protrude from the pipe P to be processed and the pair of movable pressures 2 and 2.

  In FIG. 7, the cored bar 3 has a central core member 31 and a pair of separated core members 32, 32 integrated in a rod-like shape. It is formed in a round bar shape with an equivalent core metal outer diameter D3.

In FIG. 8, the central core member 31 is formed in a Y shape when viewed from the front.
A pair of arc-shaped arm portions 61, 61 and an outer bent portion Eb of the elbow E provided to bulge from the base end portions 61a, 61a of the pair of arc-shaped arm portions 61, 61 (to be bent outward of the pipe P to be processed) A pipe flattening prevention boss part 62 for preventing the part Pb) from flattening.

The pair of arc-shaped arm portions 61, 61 are formed such that the arm axis L61 has a predetermined arm axis center radius of curvature R61 with a reference center point O (not shown) as a center point. Moreover, it has a rectangular cross section.
As shown in FIG. 8C, the boss portion 62 is formed in a semicircular cross section and has an insertion groove 63 that opens to the side of the planned outward bending portion Pb.
Further, the outer peripheral surface 62a of the boss portion 62 is formed with a radius of curvature rd having a half dimension of the pipe inner diameter dimension dp in a side view (transverse sectional view).

As shown in FIG. 8B, the insertion groove 63 has a predetermined insertion groove shaft center radius of curvature R63 with the insertion groove shaft center L63 as a center point, which is not shown in the drawing, in the front view. It is formed in an arc shape so as to have The groove bottom surface 63 a of the insertion groove 63 is continuous with the outer curved surface 61 b of the arcuate arm portion 61.
The boss lateral dimension Y62 of the boss part 62 is set to 25% or more and 40% or less of the elbow lateral dimension Ye (see FIG. 2). Preferably, it is set to 28% or more and 38% or less. By setting in this way, sufficient strength is obtained and flatness is reliably prevented.
In addition, the boss portion 62 has an outer peripheral edge portion 62b corresponding to the planned outward bending portion Pb in an arc shape centering on a reference center point O (not shown) in the front view, and the outer bent portion of the elbow E to be molded. It is formed so as to abut (contact) the inner peripheral surface Pd of Eb.

  As shown in FIGS. 7 and 9, the pair of separation core members 32, 32 are integrated with the central core member 31, and end faces 51, 51 that face each other on the reference center line S and contact each other. An arcuate guide hole 53 into which the arc-shaped arm portion 61 of the central core member 31 is removably inserted from one end surface 51, and a cross section in which the boss portion 62 of the central core member 31 is removably inserted from the one end surface 51 A semicircular space portion (relief portion) 54, and an insertion portion 55 having a circular arc when viewed from the front and protruding into the space portion 54 and removably inserted into the insertion groove 63 of the central core member 31. Yes.

As shown in FIG. 9, the guide hole axis L53 of the arcuate guide hole 53 has a guide hole axis radius of curvature R53 equivalent to the arm axis center radius of curvature R61 with a reference center point O (not shown) as the center point. It is formed to have. Further, the arcuate guide hole 53 is provided in a rectangular cross section.
Further, the insertion axis L55 of the insertion portion 55 is formed so as to have an insertion axis center curvature radius R55 equivalent to the insertion groove axis center curvature radius R63 with a reference center point O (not shown) as a center point. The insertion portion 55 has a rectangular cross section.

  Further, the separation core member 32 is bent outwardly at the distal end portion (one end surface 51 side) of the insertion portion 55 so as to be in sliding contact with the inner peripheral surface Pd of the planned outer bending portion Pb of the pipe P to be processed. A contact surface 57 is provided.

As shown in FIG. 9B, the outer curved sliding contact surface 57 is equivalent to the outer curved inner radius of curvature R4 (see FIG. 2) of the elbow E to be formed with the reference center point O as the central point in front view. Are formed in an arc shape having a radius of curvature R57.
As shown in FIG. 9C, the outer curved sliding contact surface 57 is formed in an arc shape with a radius of curvature rd which is a half of the pipe inner diameter dp in a side view (transverse view).

Further, as shown in FIG. 9, the separating core member 32 is in the vicinity of one end surface 51, and is bent inward so as to be in sliding contact with the inner peripheral surface Pd of the planned inner bending portion Pa of the pipe P to be processed. A contact surface 56 is provided.
As shown in FIG. 9C, the inner curved sliding contact surface 56 is formed in an arc shape having a radius of curvature rd which is half the pipe inner diameter dp in a side view (transverse sectional view).

  The insertion width 55 of the insertion portion 55 (insertion groove dimension W63 of the insertion groove 63) is set to 25% or more and 40% or less of the core metal outer diameter dimension D3 (pipe inner diameter dimension dp of the processed pipe P). doing. Preferably, it is set to 28% or more and 38% or less. With this setting, sufficient strength can be obtained and the work pipe P can be sufficiently supported.

Further, in FIG. 3, a connecting structure 7 for interlocking (synchronizing operation) the movable pressure 2 and the separation core member 32 is provided.
The connecting structure 7 includes a connecting hole 71 such as a cotter hole provided in the other end 32 b of the separation core member 32 protruding from the movable pressure 2, a retaining member 72 such as a cotter pin inserted into the connecting hole 71, and a movable And a contact portion 73 that abuts against a retaining member 72 provided in the pressure 2 and inserted. In the illustrated example, the contact portion 73 is composed of the other end surface 22 of the movable pressure 2.
Although not shown in the figure, the connecting structure 7 is structured so as to be interlocked by projecting a hook portion or a locking portion on the other end portion 32b of the separation core member 32 and contacting the other end surface 22 of the movable pressure 2. You can do it. Alternatively, the connection using bolts and nuts, the structure using pin holes and pins for making the movable pressure 2 and the split core member 32 skewered, and the like are free. Alternatively, one separation core member 32 may be provided with a connecting hole 71 such as a cotter hole, and the other separation core member 32 may be provided with a flange or a locking portion. That is, the connection structure 7 may not be line symmetric with respect to the reference center line S.

  As shown in FIG. 3, the outer peripheral surface 11 and the guide groove 12 of the bending roll 1, the curved sliding contact surface 24 of the movable pressure 2, the pair of arc-shaped arm portions 61 and the insertion groove 63 of the central core member 31. In addition, the arcuate guide hole 53 and the insertion portion 55 (the outer curved sliding contact surface 57) of the separation core member 32 are provided in a concentric arc shape with the reference center point O as a center point.

Next, an operation (usage method) of the elbow manufacturing apparatus of the present invention and an elbow manufacturing method will be described.
First, a straight material pipe indicated by a two-dot chain line in FIG. 1 is cut to create a pipe P to be processed having a trapezoidal shape in front view so as to be symmetrical with respect to the reference center line S as indicated by a solid line. The process pipe creation process is performed.
Further, if the material pipe is cut in a zigzag shape, the trapezoidal processed pipe P can be obtained from one material pipe P without waste, and the yield of the material can be improved.
In the pipe P to be processed, the short side in the front view is set as the internal bending planned portion Pa, and the long side is set as the external bending planned portion Pb.

Next, as shown in FIG. 4, the curved sliding contact surfaces 24, 24 of the pair of movable pressures 2, 2 are brought into contact with the outer peripheral surface 11 of the bending roll 1, and one end surface 21 of the pair of movable pressures 2, 2. , 21 are brought into contact with each other and the bending roll 1 and the movable pressure 2 are set in a pipe receiving preparation state in which the through holes 23, 23 of the pair of movable pressures 2, 2 are communicated in a straight shape. I do. One end surfaces 21 and 21 are made to coincide with the reference center line S in front view. Further, the through hole 23 and the guide groove 12 communicate with each other in the vicinity of the reference center line S.
The pipe receiving preparation process may be performed at any timing before or after the pipe to be processed.

Next, a cored bar insertion step of inserting the cored bar 3 into the workpiece pipe P is performed.
In the mandrel insertion step, first, as shown in FIG. 7, the central core member 31 and the pair of separated core members 32, 32 are integrated into a rod shape. The arcuate guide hole 53 of the separating core member 32 is brought close to the pair of arcuate arm parts 61 and 61 of the central core member 31 from both sides, and the arcuate arm part 61 is inserted into the arcuate guide hole 53. Further, the insertion portion 55 of the separation core member 32 is inserted into the insertion groove 63 of the boss portion 62 of the center core member 31 from both sides, and the boss portion 62 of the center core member 31 corresponds to the space portion 54 of the separation core member 32. Let The pair of separation core members 32 and 32 are brought close to each other, and the one end surfaces 51 and 51 are brought into contact with each other to form the cored bar 3 integrated in a rod shape. The cored bar 3 is line symmetric with respect to the processing reference center line S.

  Thereafter, the rod-shaped cored bar 3 is inserted into the processed pipe P. During this insertion, the inner curved sliding contact surface 56 of the separation core member 32 is made to correspond to the planned inner bending portion Pa of the pipe P to be processed, and the boss portion 62 of the central core member 31 and the outer bending of the separation core member 32 are made. The sliding contact surface 57 (insertion portion 55) is made to correspond to the planned outward bending portion Pb of the processed pipe P, and the horizontal center line of the processed pipe P and the horizontal center line of the cored bar 3 are matched (reference center line) The one end face 51, 51 is disposed on S), and the core metal inserting step is completed. In addition, you may perform a metal core insertion process at any timing before and after an acceptance preparation process.

Then, the cored bar 3 inserted through the pipe P to be processed is inserted and connected to the through holes 23 and 23 of the pair of movable pressures 2 and 2 in a pipe receiving preparation state, and as shown in FIG. The bending preparation process which makes a state is performed.
In the bending preparation step, the inner bending planned portion Pa of the pipe P to be processed is made to correspond to the guide groove 12, the horizontal center line of the pipe P to be processed, and the horizontal center line of the core bar 3 (the horizontal direction of the central core member 31). The reference center line S and the one end surfaces 51, 51) of the pair of separating core members 32, the one end surfaces 21, 21 of the pair of movable pressures 2, 2, and the lateral center line of the bending roll 1 are on the reference center line S. It arranges in.

  Next, the retaining members 72, 72 are inserted (press-fitted) into the connection holes 71, 71 exposed from both sides of the pair of movable pressures 2, 2, and the retaining member 72 is brought into contact with the movable pressure 2. (The other end surface 22), the separation core member 32 is connected to the movable pressure 2 and the cored bar 3 is in a bending preparation state in which it is positioned with respect to the pair of movable pressures 2 and 2 and the bending roll 1, End the bending preparation process.

Next, the bending process which shape | molds the to-be-processed pipe P in the elbow E is performed.
In the bending process, the bent sliding contact surfaces 24, 24 of the pair of movable pressures 2, 2 are kept in contact with the outer peripheral surface 11 of the bending roll 1, as shown in FIG. The pair of movable pressures 2 and 2 are slid in opposite circumferential directions N1 and N2. The pipe P to be machined is bent by the inner peripheral surface of the through hole 23 of the movable pressure 2 and the inner curved sliding contact surface 56 of the separation core member 32 with the horizontal center line of the pipe aligned with the reference center line S. 1 is pushed into the guide groove 12.

  In the bending process, each separation core member 32, 32 is guided by the arc-shaped arm portion 61 of the central core member 31 while being linked (synchronized) with the sliding of the movable pressures 2, 2. Are moved away from each other so as to draw, respectively, in the direction of exiting from both sides of the pipe P to be processed. The pair of movable pressures 2, 2 and the pair of separation core members 32, 32 are separated from each other while drawing an arcuate locus with the reference center point O as a center point.

  When the pair of movable pressures 2, 2 and the pair of separation core members 32, 32 draw an arcuate locus, the inner curved sliding contact surface 56 of the separation core member 32 is the planned inner curvature portion Pa of the pipe P to be processed. Is pressed against the guide groove 12 of the bending roll 1 and slidably comes into contact with the inner peripheral surface Pd of the planned inner bending portion Pa (so that wrinkles are extended to both sides).

Further, the pair of separating core members 32 and 32 are supported in the direction of exiting from the openings at both ends of the pipe P to be processed while supporting the pair of arc-shaped arm portions 61 and 61 of the central core member 31 (opposite circumferential directions N1 and N2). The center core member 31 is kept at the inner center position of the pipe P to be processed with the left and right center lines thereof aligned with the processing reference center line S.
The outward bending planned portion Pb is deformed so as to be along the boss portion 62 of the central core member 31.
Further, the outer bending contact surface 57 of the insertion portion 55 of the separation core member 32 is slidably contacted with the inner peripheral surface Pd of the processed pipe P on the side of the planned outer bending portion Pb.
The through hole 23 of the movable pressure 2 prevents the diameter of the processed pipe P from being increased from the outer peripheral surface side of the processed pipe P. Further, the outer curved sliding contact surface 57 of the separation core member 32 and the inner peripheral surface of the through hole 23 slide while sandwiching the planned outer curved portion Pb, thereby preventing flattening.

  Further, as shown in FIG. 11, the movable pressures 2 and 2 are processed pipes P to a predetermined forming angle α slightly larger (2 ° to 3 °) than the predetermined bending angle θ in consideration of the back spring. Bend. Immediately after exceeding the forming angle α, the arc-shaped arm portion 61 remains engaged with the arc-shaped guide hole portion 53 even if the separation core members 32, 32 come out from both sides of the molded elbow E, and the central core member No. 31 is prevented from moving toward the reference center point O side (radial inward side), and the boss portion 62 is in close contact with the inner peripheral surface Pd of the portion Pb to be bent at the inner center position of the pipe P to be processed. Stay in state.

  In the bending process, a compressive stress is generated in the planned bending portion Pa in the pipe, and the thickness of the inner bending portion Ea of the formed elbow E may be thicker than the thickness of the pipe P to be processed. However, the inner curved sliding contact surface 56 of the split core members 32 and 32 is in sliding contact with the inner peripheral surface Pd of the pipe P to be processed, thereby preventing the occurrence of thickening and wrinkling. And the surplus meat that was scheduled to be wrinkled in the inner bending planned portion Pa loses the escape place, moves to the outer bending planned portion Pb, and prevents the thinning of the outer bent portion Eb of the molded elbow E. That is, when the pipe P to be processed is bent, the excess thickness of the inner bending scheduled portion Pa is offset by moving to the outer bending planned portion Pb, and the thickness of the molded elbow E becomes uniform.

  Further, in the bending process, there is a possibility that a pulling force is generated in the pipe bending-scheduled portion Pb, and flattening such as crushing may occur. However, the pipe flattening prevention boss portion 62 of the central core member 31 is formed on the pipe to be processed. In addition to staying at the inner central position of P, the insertion portion 55 (outer bending sliding contact surface 57) of the split core members 32, 32 is in sliding contact with the inner peripheral surface Pd of the pipe P to be processed, so that the flatness and the reference Deformation that dents toward the center point O is prevented and held in a perfect circle. Moreover, thinning is suppressed because the surplus meat of the inner bending planned portion Pa moves to the outer bending planned portion Pb. The outer peripheral side (outer peripheral side) of the pipe P to be processed is restrained by the inner peripheral surface of the through hole 23 of the movable pressure 2 to prevent deformation.

More specifically, on the basis of the thickness dimension of the pipe P to be processed, the increase / decrease in the thickness dimension of the molded elbow E can be suppressed within a range of ± 7%.
This is because if the thickness of the pipe P to be processed is the JIS standard thickness of the straight pipe type pipe, the elbow thickness after molding is -12.5% of the standard thickness (specified thickness). And comply with JIS B2321 of the JIS joint standard.
Further, when the pipe P to be processed is used as a reference, the deformation ratio of the outer diameter dimension De or the inner diameter dimension de (see FIG. 2) at both ends of the molded elbow E can be suppressed within a range of ± 2%. Further, the deformation rate of the outer diameter of the bent portion can be suppressed within a range of ± 3%.
Therefore, it is not necessary to use a special material pipe having a wall thickness larger than that of the elbow E to be molded, and a general commercially available straight pipe type pipe (for example, an aluminum alloy seamless pipe conforming to JIS G3459). The elbow E can be manufactured from the processed pipe P made of a material), which is economical and can shorten the delivery time. Further, a thin elbow E having an elbow thickness of 2 mm to 3 mm can be seamlessly formed.

Further, since the movable pressure 2 has only to be slid from the lateral center line (reference center line S) of the pipe P to be processed by an angle that is half the predetermined forming angle α, the manufacturing can be performed quickly.
For example, if the bending angle θ is 90 ° and the forming angle α is 92 ° to 93 °, the movable pressure 2 may be slid by 46 ° to 46 ° 30 ′. For example, it can be molded in half the time compared to moving one movable pressure from 92 ° to 93 °.

  In the bending process, as shown in FIG. 12, when the pair of movable pressures 2 and 2 are separated (opened) from each other to a predetermined sliding opening angle β larger than a predetermined forming angle α, an arc shape is formed. The arm portion 61 is removed from the arcuate guide hole portion 53, the central core member 31 is in a free state, the elbow E can be separated from the bending roll 1, and the bending process is completed. Note that the elbow E formed in this way may be press-molded with a final finish mold to increase the dimensional accuracy.

  Further, as shown in FIG. 13, the driving means 8 for pressing the pair of movable pressures 2 and 2 against the bending roll 1 and sliding them in the opposite circumferential directions N1 and N2 is provided so as to be relatively close to and away from. And a bending machine 1 and a pair of movable pressures 2 between a first board 81 provided at a lower position and a second board 82 provided at an upper position. , 2 with the planned bending portion Pb of the pipe P to be processed facing downward (the guide groove 12 of the bending roll 1 is disposed as a downward opening), and the upper end of the bending roll 1 is placed on the second plate 82. The movable pressure 2 is disposed so as to be movable upward along the outer peripheral surface 11 from the lower part of the bending roll 1, and the movable pressure 2 and the first panel 81 are connected via a link mechanism 83, The bending roll 1 is pressed downward by the lowering of the two plates 82, and a pair of possible by the pair of link mechanisms 83, 83 It is slid to the curved sliding contact surface 24 of the bending opposite circumferential direction N1, N2 while keeping in contact with the circumferential surface of the roll 1 of the pressure 2,2, is configured to mold the elbow E (method).

With this configuration, when the arc-shaped arm portion 61 of the central core member 31 is removed from the separation core member 32, the natural elbow E and the central core member 31 in the elbow E naturally fall and the elbow E is removed. Work can be omitted and manufacturing efficiency can be improved. Further, the central core member 31 can be easily and quickly removed from the molded elbow E. A special tool or device for removing the central core member 31 is not required.
The driving means 8 is not limited to the illustrated embodiment, and may be configured such that, for example, the first board 81 rises from the state shown in FIG. Alternatively, a configuration in which the upper and lower sides are arranged upside down in FIG. 13 (arrangement in which the planned outward bending portion Pb faces upward) may be employed. 13 may be driven so that the first board 81 and the second board 82 are relatively close to each other in the horizontal direction. Further, the bending roll 1 may be fixed and the movable pressures 2 and 2 may be connected to the hydraulic cylinders and driven. Further, the drive mechanism 8 may be of any electric or manual drive source, and the operation mechanism may be a hydraulic or pneumatic type, or a mechanical feed type such as a gear or a rack.

In the present invention, the design can be changed, and the material of the pipe P to be processed is a metal having an elongation of 15% or more at normal temperature or in a heated state in addition to metals such as aluminum, stainless steel, nickel, copper, and iron. It may be made of (alloy). Also, seamless pipes and welded pipes are free. The material of the bending roll 1, the movable pressure 2, and the cored bar 3 is metal or the like. Further, the elbow E to be molded is free with a bending angle θ of 45 ° or 90 °. Further, the present invention is not limited to cold bending, and may be performed while heating by attaching a heating means such as a heater to the movable pressure 2.
In the present invention, setting the dimensions to be equal includes not only the case where the dimensions match, but also the case where the dimensions are set within a tolerance range in accordance with the JIS standard.

  As described above, the elbow manufacturing apparatus according to the present invention moves the pipe P to be machined by moving the bending roll 1 for bending the pipe P to be worked and the circumferential directions N1 and N2 opposite to each other while being in sliding contact with the bending roll 1. A pair of movable pressures 2 and 2 that press against the bending roll 1, and a cored bar 3 that is configured to be separable into three parts and is integrated into a rod shape and inserted into the pipe P to be processed. The core metal 3 is interlocked and connected to the pair of movable pressures 2 and 2, respectively, and the movable pressures 2 and 2 move in circumferential directions N1 and N2 opposite to each other so as to draw an arcuate locus while being separated from each other. Each of the separation core members 32 includes a pair of separation core members 32 and 32 that are in sliding contact with the inner peripheral surface Pd of the processing pipe P, and a central core member 31 disposed between the pair of separation core members 32 and 32. 32 have an arcuate guide hole 53, and the central core member 31 has an arcuate guide hole 53. Since it has a pair of arc-shaped arm portions 61 and 61 slidably inserted into the hole 53 and a pipe flattening prevention boss portion 62, the outer diameter (inner diameter) size is the same as or close to the elbow E to be molded. Elbow E can be manufactured from commercially available pipes (conforming to JIS standards) with wall thickness. It is possible to manufacture elbows E with seamless and seamless wall thickness such as welding. It is possible to suppress the thinning of the outer bend planned portion Pb and the thickening of the inner bend planned portion Pa when the pipe P is bent. A straight pipe compliant with the JIS standard can be bent while keeping it within the thickness tolerance of the JIS standard (within minus 12.5% of the specified thickness). It is possible to suppress the occurrence of flatness, crushing, cracks, cracks, and wrinkles at the bent portion, to reduce the occurrence of defective products, and to manufacture a high-quality elbow E stably and efficiently. A clamping device for gripping the workpiece pipe P is not required, and the device can be simplified. In addition, the workpiece pipe P does not require a clamping margin, and the material can be used efficiently (good yield). It can be easily manufactured without skilled skills (experience). Further, since the elbow E can be manufactured if the pair of movable pressures 2 and 2 can be moved, the driving means 8 can be made small and simple. Moreover, even if it is a cold bending, the elbow E can be manufactured easily and generation | occurrence | production of global warming gas, such as an energy saving and a carbon dioxide, can also be suppressed.

  The elbow manufacturing method of the present invention includes a cored bar insertion step of inserting a cored bar 3 having a divided structure for preventing flattening into the processed pipe P, and the processed pipe P along the bending roll 1. The core metal 3 includes a central core member 31 and a pair of separation core members 32 and 32 disposed on both sides of the central core member 31 so as to be separable into three. In the core metal inserting step, the central core member 31 and the pair of separated core members 32, 32 are integrated into a rod shape and inserted into the processed pipe P, and when the processed pipe P is bent in the bending step, The pair of separation core members 32, 32 are slidably contacted with the inner peripheral surface Pd of the pipe P to be processed while being separated from each other so as to draw an arcuate locus, and the central core member 31 is located at the inner center of the pipe P to be processed. Since it stays in place and prevents pipe flatness, it is the same as or close to the elbow E to be molded. Outer diameter (inner diameter) dimensions and wall thickness of commercial products having (conforming to JIS standard) can be produced elbow E from the pipe. It is possible to manufacture elbows E with seamless and seamless wall thickness such as welding. It is possible to suppress the thinning of the outer bend planned portion Pb and the thickening of the inner bend planned portion Pa when the pipe P is bent. A straight pipe compliant with the JIS standard can be bent while keeping it within the thickness tolerance of the JIS standard (within minus 12.5% of the specified thickness). It is possible to suppress the occurrence of flatness, crushing, cracks, cracks, and wrinkles at the bent portion, to reduce the occurrence of defective products, and to manufacture a high-quality elbow E stably and efficiently. A clamping device for gripping the workpiece pipe P is not required, and the device can be simplified. Also, the workpiece pipe P does not require a clamping fee, and the material can be used efficiently. It can be easily manufactured without skilled skills. Further, since the elbow E can be manufactured if the pair of movable pressures 2 and 2 can be moved, the driving means 8 can be made small and simple. Moreover, even if it is a cold bending, the elbow E can be manufactured easily and generation | occurrence | production of global warming gas, such as an energy saving and a carbon dioxide, can also be suppressed.

1 Bending roll 2 Movable pressure 3 Core metal
31 Center core member
32 Separation core member
53 Arc guide hole
61 Arc-shaped arm
62 Boss for pipe flattening prevention N1 circumferential direction N2 circumferential direction P Pipe to be processed Pd Inner circumferential surface

Claims (2)

A bending roll (1) for bending the pipe (P) to be processed, and the circumferential direction (N1) (N2) opposite to each other while sliding on the bending roll (1) to bend the pipe (P) to be processed A pair of movable pressures (2) and (2) that press against the roll (1) and a split structure that is configured to be separable into three parts and integrated into a rod shape and inserted into the pipe (P) to be processed. A metal core (3),
The core metal (3) is interlocked and connected to the pair of movable pressures (2) and (2), respectively, and moves in the circumferential directions (N1) and (N2) in which the movable pressures (2) and (2) are opposite to each other. A pair of separation core members (32) and (32) that are slidably in contact with the inner peripheral surface (Pd) of the pipe (P) while being spaced apart from each other so as to draw an arcuate locus, and a pair of the separation core members (32 ) (32) and a central core member (31) disposed between,
Each of the separation core members (32) (32) has an arcuate guide hole (53),
The central core member (31) includes a pair of arc-shaped arm portions (61) (61) slidably inserted into the arc-shaped guide hole portion (53) and a pipe flattening prevention boss portion (62). The elbow manufacturing apparatus characterized by the above-mentioned. A cored bar inserting step of inserting a cored bar (3) having a divided structure for preventing flattening into the processed pipe (P), and pressing the processed pipe (P) along the bending roll (1). A bending process,
The core metal (3) includes a central core member (31) and a pair of separation core members (32) and (32) disposed on both sides of the central core member (31), and can be separated into three. Composed of
In the core metal insertion step, the central core member (31) and the pair of separated core members (32) and (32) are integrated into a rod shape and inserted into the processed pipe (P),
In the bending process, when the pipe to be processed (P) is bent, the pipe to be processed (P) while separating the pair of separation core members (32) and (32) from each other so as to draw an arcuate locus. The inner core surface (Pd) is slidably contacted, and the central core member (31) stays at the inner central position of the pipe (P) to be processed to prevent the flattening of the pipe.

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