CN113477818B - Bending process for bending flanged bent pipe by adopting numerical control pipe bending machine - Google Patents
Bending process for bending flanged bent pipe by adopting numerical control pipe bending machine Download PDFInfo
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- CN113477818B CN113477818B CN202110697731.6A CN202110697731A CN113477818B CN 113477818 B CN113477818 B CN 113477818B CN 202110697731 A CN202110697731 A CN 202110697731A CN 113477818 B CN113477818 B CN 113477818B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D43/00—Feeding, positioning or storing devices combined with, or arranged in, or specially adapted for use in connection with, apparatus for working or processing sheet metal, metal tubes or metal profiles; Associations therewith of cutting devices
- B21D43/003—Positioning devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D7/00—Bending rods, profiles, or tubes
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Abstract
The invention discloses a process for bending a flanged bent pipe by adopting a numerical control pipe bending machine, which sequentially comprises the following steps: s1, clamping a flange type pipeline: one end with a flange of the bent pipe with the flange is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bending machine; s2, dynamically correcting the initial position of the flange hole site after clamping the flanged bent pipe: s3, numerical control bending of the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on a numerical control pipe bending machine, and controlling the action of a servo trolley of the pipe bending machine through the numerical control pipe bending program to realize three-dimensional bending of a pipe; the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bending machine; the self-centering clamping mechanism is provided with an L-shaped claw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped claw. The invention improves the bending precision of the flanged pipeline and solves the problem of unreliable clamping.
Description
Technical Field
The invention relates to the technical field of pipe bending, in particular to a process for bending a flanged bent pipe by adopting a numerical control pipe bender.
Background
The numerical control pipe bender is an automatic device for manufacturing a bent pipe by bending and deforming a pipe.
In the prior art, a typical numerical control pipe bender comprises a pipe bender main machine (servo trolley), wherein the main machine part of the pipe bender is integrally arranged on a movable guide rail, and the pipe bender is driven by a servo motor to realize the movement on the guide rail; the main machine of the pipe bending machine mainly comprises a numerical control rotating mechanism (also called a trolley rotating mechanism) driven by a speed reduction transmission mechanism, and a chuck for clamping a pipe is arranged on the numerical control rotating mechanism. When in bending, the chuck clamps the pipe, and under the cooperation of the pipe bending mold, the numerical control system controls the rotation angle and the movement distance of the trolley rotating mechanism, so that the three-dimensional bending of the pipe is realized.
The bending of the pipe is classified into the bending of the pipe without a flange and the bending of the pipe with a flange according to the bending process. The pipe without flange has no flange at the end of the pipe, and the chuck clamps the pipe part to be directly bent during bending; the flange pipe is provided with a flange (also called pipe flange) at the end of the pipe, and the outer circle of the pipe flange is clamped by a chuck for bending.
The numerical control pipe bender is commonly used in shipyards. Most units of the current shipyard adopt a process of bending pipes first and welding flanges later. The process has low efficiency, more labor and higher requirements for workers. After the pipe bending experience is accumulated for many years, a small part of shipyards adopt a first welding and last bending process, but the technology is influenced by the rotation precision of a numerical control pipe bending machine, the clamping of the outer edge of a clamping flange of a servo trolley is unreliable, the error of positioning the flange by a pin shaft is large, the flange is welded on a straight pipe and has errors, the end face of the flange is not attached to the end face of the trolley, the flange is welded with the straight pipe and deforms, so that the error is relatively large, the flange cannot rotate to a required position, and the deviation of the bent flange pipe is too large to use.
In the prior art, for bending a pipe with a flange, in order to ensure that the circumferential position of a bolt hole on the flange is accurate relative to the three-dimensional bending shape position of the pipe, a positioning pin shaft is usually arranged on a chuck, and one bolt hole on the flange is sleeved into the positioning pin shaft during clamping to realize single-hole positioning of the flange so as to improve the positioning precision of the circumferential position of the flange.
However, the single hole positioning method of the flange pipe has the following problems:
firstly, because a large gap is formed between the flange and the pipe, the flange and the pipe are easy to be eccentric and inclined during assembly, so that the positions of bolt holes on the flange, particularly the circumferential positions, are greatly deviated relative to the center of the pipe; if the circumferential position of the flange is determined by positioning only one single hole, a larger circumferential position error occurs in the other single hole which is arranged 180 degrees relative to the single hole, so that the subsequent butt joint assembly of the pipeline after the three-dimensional bending of the pipe is difficult, and even the phenomenon that the pipe cannot be assembled occurs.
Secondly, the rotating mechanism of the servo trolley of the pipe bending machine has certain rotating errors, and the circumferential errors of the bolt hole position on the flange relative to the three-dimensional bent pipe can be caused, so that the butt joint assembly of the pipeline is difficult, and even the phenomenon that the pipeline cannot be assembled occurs.
Third, when infrared hole measurement is adopted for positioning, only a single hole can be detected, and accurate positioning cannot be realized due to influences of factors such as punching errors, hole position relative position errors, flange welding errors and the like.
Disclosure of Invention
In order to solve the problems, the invention provides a bending process for bending a flanged bent pipe by adopting a numerical control pipe bending machine, which improves the bending precision of the flanged pipe. The specific technical scheme is as follows:
a technology for bending a flanged bent pipe by adopting a numerical control pipe bending machine sequentially comprises the following steps:
s1, clamping a flange type pipeline: one end with a flange of the flanged bent pipe is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bending machine, and the straight pipe part of the flanged pipeline is directly clamped by avoiding the flange during clamping;
s2, dynamically correcting the initial position of the flange hole site after clamping the flanged bent pipe:
s3, numerical control bending of the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on a numerical control pipe bending machine, and controlling the action of a servo trolley of the pipe bending machine through the numerical control pipe bending program to realize three-dimensional bending of a pipe;
the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bending machine; the self-centering clamping mechanism is provided with an L-shaped claw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped claw.
In the present invention, the self-centering gripping mechanism may take various forms, including but not limited to the following:
the self-centering clamping mechanism is a three-jaw self-centering chuck, and jaws on the three-jaw self-centering chuck are changed into L-shaped jaws so as to avoid flanges and directly clamp straight pipe parts of flanged pipelines.
And the second structure is that the self-centering clamping mechanism is a two-claw self-centering chuck, and claws on the two-claw self-centering chuck are changed into L-shaped claws so as to avoid flanges and directly clamp straight pipe parts of the flanged pipelines.
During clamping, a flange on the flanged pipeline transversely enters an L-shaped neutral gear of the L-shaped claw, and then the straight pipe part of the flanged pipeline is directly clamped through the claw head of the L-shaped claw.
A third structure, the self-centering clamping mechanism adopts a large-opening self-centering powerful clamping device to avoid the flange and directly clamp the straight pipe part of the flanged pipeline; the large-opening self-centering powerful clamping device comprises a rotating sleeve arranged on a servo trolley of the pipe bending machine, a hollow seat ring fixed at the front end of the rotating sleeve, a plurality of L-shaped clamping jaws which are arranged at the front end of the hollow seat ring and are distributed at intervals along the circumferential direction and are used for clamping flanged pipelines, and a push-pull sleeve which is arranged on the outer circle of the rotating sleeve and can move along the central axis direction of the rotating sleeve so as to clamp the L-shaped clamping jaws, wherein the L-shaped clamping jaws comprise rotating arms and clamping blocks connected with the front end of the rotating arms, the rotating arms are connected with the front end of the rotating sleeve in a rotating way through pin shafts, inner taper holes are formed in the push-pull sleeve, the outer side parts of the rotating arms, which are far away from the central axis, are provided with outer taper surfaces matched with the inner taper holes of the push-pull sleeve, and the clamping blocks are positioned at the inner side parts of the rotating arms, which are close to the central axis; the rotating arm is connected with a spring for automatically opening the L-shaped clamping jaw.
Preferably, the clamping blocks of the L-shaped clamping jaws are provided with cambered surfaces which are matched with the outer circle of the pipe.
According to the invention, the front end of the hollow seat ring is provided with the front flange, a plurality of positioning grooves parallel to the central axis are formed on the outer circle of the front flange along the circumferential direction, and the rotating arms of the L-shaped clamping jaws are matched with the positioning grooves and are in rotating connection through the pin shafts.
Preferably, the number of the L-shaped claws in the large-opening self-centering strong clamping device is four and the L-shaped claws are uniformly arranged at intervals along the circumferential direction.
The L-shaped claw has a large rotation range, can realize the opening and the closing of a large opening, so that the L-shaped claw can be well adapted to the shaking of the flanged pipeline during hoisting, on one hand, the pipe is not easy to hurt and collide with wool, and on the other hand, the efficiency of clamping the flanged pipeline is also improved.
The large-opening self-centering powerful clamping device also utilizes the conical surface of the push-pull sleeve to realize the clamping of the L-shaped clamping jaw, and the clamping device cooperates with the push-pull oil cylinder and the lever type shifting fork to realize powerful clamping under a compact structure; the push-pull oil cylinder can meet the requirement of clamping force by using a small oil cylinder, and compared with the traditional clamping mode of matching a large-tonnage oil cylinder with a chuck, the manufacturing cost of the push-pull oil cylinder can be greatly reduced.
As a preferred scheme for realizing the automatic opening of the L-shaped clamping jaw by the large-opening self-centering strong clamping device, the clamping groove is formed in the outer side part, far away from the central axis, of the rear end of the rotating arm, the spring is a tension spring, and the tension spring is sleeved on the clamping grooves of the rotating arms of the L-shaped clamping jaw for clamping the flanged pipeline after being encircled into a ring shape.
Preferably, an inner flange is arranged at the inner hole part of the front end of the rotary sleeve, a rear flange is arranged at the rear end of the hollow seat ring, and the rear flange of the hollow seat ring is fixedly connected with the inner flange of the rotary sleeve through bolts.
In the invention, the rotary sleeve is connected with the output end of a worm gear box of the servo trolley of the pipe bending machine.
According to the invention, an annular groove is formed in the outer circle of the push-pull sleeve, a first support is arranged on the worm gear box, a lever type shifting fork is rotationally connected to the first support through a first hinge shaft, a roller matched with the annular groove is rotationally arranged at the front end of the lever type shifting fork, a push-pull oil cylinder is further arranged on the servo trolley of the pipe bending machine, and a telescopic head of the push-pull oil cylinder is rotationally connected with the rear end of the lever type shifting fork through a second hinge shaft.
In the invention, a second support is arranged on the servo trolley of the pipe bending machine, and the oil cylinder shell of the push-pull oil cylinder is rotationally connected to the second support through a third hinge.
In the invention, the axes of the first hinge shaft, the second hinge shaft, the third hinge shaft and the roller are mutually parallel.
In the invention, the servo trolley of the pipe bending machine is arranged on the moving guide rail and moves on the moving guide rail through the linear driving mechanism.
Preferably, in order to further expand the clamping range of the flanged pipeline, a large chamfer is arranged on the inner side of the clamping block of the L-shaped clamping jaw.
During bending, an auxiliary mandrel can be inserted from the inner hole at the tail end of the servo trolley of the pipe bending machine to the inner hole direction of the rotary sleeve of the clamping device, and the auxiliary mandrel is positioned in the inner hole of the pipe so as to realize auxiliary bending of the pipe.
Preferably, in the dynamic correction of the initial position of the flange hole position after clamping the flanged bent pipe in the step S2, the positions of a plurality of holes on the flange are identified by a visual identification device arranged on the numerical control pipe bender, and the correction of the initial angle position of the bending is performed according to the hole position errors of the plurality of holes on the identified flange.
More preferably, the dynamic correction of the initial position of the flange hole after clamping the flanged bent pipe in step S2 sequentially includes the following steps:
(1) And (3) identifying a single hole of the flange: setting a camera coordinate system, and setting one single hole A and one single hole A on a pipe flange of the flange type pipeline through a visual setting device;
(2) The rotation center position is set as follows: the trolley rotating mechanism rotates to drive the flanged pipeline on the self-centering clamping mechanism to rotate together, the single hole A on the pipe flange is rotated to a plurality of different positions, the coordinates of the single hole A at the different positions are detected by the vision identifying device, the rotating center position is calculated according to the coordinates of the single hole A at the plurality of different positions, and then an X-Y coordinate system taking the rotating center as an original point is established;
(3) Calculating a hole site angle correction amount: taking the single hole A and the single hole B which is arranged on the pipe flange and is 180 degrees away from the single hole A, and calculating an included angle alpha between the single hole A and a Y axis according to the position of the single hole A in an X-Y coordinate system; then the trolley rotating mechanism rotates 180 degrees, the single hole B rotates to a corresponding position, the position of the rotated single hole B in an X-Y coordinate system is distinguished by a visual distinguishing device, and an included angle beta between the single hole B and a Y axis is calculated; taking the average value of alpha and beta, namely (alpha+beta)/2, as a hole site angle correction amount;
(4) Hole site correction: the trolley rotating mechanism reversely rotates 180 degrees to reset the single hole B which is originally rotated 180 degrees, and then the trolley rotating mechanism rotates to enable the single hole A to be located at the position with the included angle (alpha+beta)/2 with the Y axis and serve as a correction position of the single hole A;
(5) Setting a bending initial angle: the trolley rotating mechanism of the pipe bending machine rotates to rotate the position of the single hole A to a starting angle set by a program, and then the pipe is automatically bent according to a bending program of the pipe bending machine.
It should be noted that, in the flanged pipeline used in reality, the bolt holes on the pipe flange are basically even holes (such as four holes, six holes, eight holes, etc.) which are uniformly distributed. Therefore, in the hole position correction, two holes A and B which are 180 degrees away from each other are adopted to carry out visual identification detection and correction after rotating 180 degrees. If odd holes or other non-uniformly distributed special distribution holes appear, two holes with the farthest distance on the pipe flange can be selected, according to the theoretical design included angles of the two holes, a corresponding theoretical design included angle is turned during hole position correction, then corresponding alpha and beta angle values are obtained through visual identification and detection, and then hole position correction is carried out.
Theoretically, the position of the rotation center can be calculated by knowing the coordinates of the three positions of the single hole a. However, in order to improve the accuracy of the identification of the rotation center position, the following further improvements may be adopted: in the step (2), the single hole A on the pipe flange is rotated to seven different positions, and the rotation center position is calculated according to coordinates of the single hole A at the seven different positions.
In order to improve the bending precision, the invention adopts the following scheme that: before bending the flanged pipelines in batches, a bending test is performed in advance, the flanged pipelines manufactured by the bending test are scanned by adopting a three-dimensional laser scanner to form three-dimensional solid models of the flanged pipelines, the scanned solid models are imported into three-dimensional design software and are compared with three-dimensional design theoretical models of the flanged pipelines to obtain actual bending errors of all bending parts on the flanged pipelines, and the actual bending errors are written into a bending program as compensation quantities to form the bending program with bending error compensation; and when the flange-type pipeline is bent formally, bending is performed by using the bending program with bending error compensation.
When the test is actually carried out, the bending test can be respectively carried out section by section according to the number of the bent sections of the pipeline in sequence, and after the bending test and the program compensation of the former section are finished, the bending test and the program compensation of the latter section are carried out until all the bending part tests and the program compensation are finished. Its advantage is high correction accuracy, but the number of tests that need to be carried out is more.
In order to achieve both correction precision and test frequency reduction, the preferred scheme is to perform local comparison for each bending node after a one-time bending test; when a plurality of bending nodes are arranged on the flanged pipeline, the bending nodes are taken in three-dimensional design software to be respectively compared, bending errors of the positions of the bending nodes are obtained, and then the bending errors of the positions of the bending nodes are used as compensation amounts to be written into a bending program to form the bending program with bending error compensation.
The numerical control pipe bender comprises a pipe bender servo trolley, a trolley rotating mechanism arranged on the pipe bender servo trolley, a self-centering clamping mechanism connected to the trolley rotating mechanism and used for clamping a flanged pipeline, and a visual identification device arranged beside the self-centering clamping mechanism and used for detecting a flange hole position on the flanged pipeline; the visual identification device comprises a camera and a visual identification system connected with the camera, wherein the visual identification system and the camera are respectively connected with a control system of the numerical control pipe bending machine.
Preferably, the camera is arranged on a lifting mechanism, and the lifting mechanism is connected with a control system of the numerical control pipe bending machine.
The beneficial effects of the invention are as follows:
firstly, according to the pipe bending process for bending the flanged pipe by adopting the numerical control pipe bending machine, the L-shaped clamping jaws are adopted for clamping the pipe, and the L-shaped clamping jaws avoid the flange to directly clamp the straight pipe part of the flanged pipe, so that the defects of large clamping deflection error and poor pipe bending precision caused by directly clamping the pipe flange by the traditional pipe bending machine are overcome.
Secondly, according to the pipe bending process for bending the flanged pipe by adopting the numerical control pipe bending machine, the hole positions on the flange are identified through the visual identification system, the initial positions of the hole positions of the flange are dynamically corrected according to the errors of the identified hole positions of the flange, the circumferential positions of the pipe flange are corrected to an optimal angle, and the optimal position setting of the circumferential hole positions on the flange relative to the three-dimensional bent pipeline is realized, so that the pipe bending precision is improved, and the defect that the installation is difficult due to the large circumferential errors of the hole positions on the flange formed by adopting single-hole positioning in the traditional flange pipe bending is overcome.
Thirdly, according to the pipe bending process for bending the flanged pipe by adopting the numerical control pipe bending machine, the large-opening self-centering powerful clamping device is adopted for clamping the pipe, so that the large-opening self-centering powerful clamping device can avoid the flange to directly clamp the outer diameter of the pipe, the clamping force is large, the clamping is reliable, and the defect that the pipe flange is damaged due to the fact that the pipe flange is clamped by the traditional numerical control pipe bending machine is avoided; compared with the traditional method for clamping the outer circle of the flange, the method for directly clamping the outer diameter of the pipe does not have the phenomenon of clamping deflection, thereby improving the quality of three-dimensional bending of the pipe.
Fourth, the technology for bending the flanged bent pipe by adopting the numerical control pipe bending machine adopts a visual identification system to identify and detect the hole position of the flange, and the detection after the flanges with different specifications are replaced is not affected (the flanges with different specifications have different hole diameters, different hole circumference diameters and different flange thicknesses).
Fifth, the pipe bending process for bending the flanged pipe by the numerical control pipe bending machine can avoid the problem of inaccurate pipe bending precision caused by errors generated in the actual production process, can optimize the processing process of the ship yard pipeline, realizes allowance-free accurate blanking, automatic pipe coding, automatic flange welding and automatic pipe bending by the numerical control pipe bending machine, can realize workshop intelligent production, greatly saves labor and improves production efficiency. The visual recognition system is not affected by different flange specifications, so that the full coverage of the system is achieved.
Drawings
FIG. 1 is a schematic diagram of a process flow for bending a flanged bent pipe by a numerical control pipe bender;
FIG. 2 is a schematic diagram of dynamic hole position correction in a process for bending a flanged pipe by using a numerical control pipe bender;
FIG. 3 is a schematic diagram of a numerical control pipe bender with a large opening self-centering strong clamping device;
fig. 4 is a schematic structural diagram of a self-centering clamping mechanism using a three-jaw self-centering chuck or a two-jaw self-centering chuck (the jaws are L-shaped jaws);
FIG. 5 is a partial cross-sectional view of FIG. 3;
fig. 6 is a schematic structural view of the large opening self-centering strong clamping device in fig. 5 after the L-shaped clamping jaw is opened (in the figure, a large chamfer is arranged on the inner side of the clamping block of the L-shaped clamping jaw).
In the figure: 1. the servo trolley of the pipe bending machine comprises a servo trolley 2, a rotary sleeve 3, a hollow seat ring, a 4, an L-shaped claw, a 5, a push-pull sleeve, a 6, a rotating arm, a 7, a clamping block, a 8, a pin shaft, a 9, an inner taper hole, a 10, an outer taper surface, a 11, a spring, a 12, a front flange, a 13, a positioning groove, a 14, a clamping groove, a 15, an inner flange, a 16, a rear flange, a 17, a bolt, a 18, a worm gear box, a 19, an annular groove, a 20, a first support, a 21, a first hinge shaft, a 22 and a lever type shifting fork, 23, a roller, 24, a push-pull oil cylinder, 25, a telescopic head, 26, a second hinge shaft, 27, a second support, 28, an oil cylinder shell, 29, a third hinge shaft, 30, a movable guide rail, 31, a straight pipe, 32, a pipe flange, 33, a linear driving mechanism, 34, a lifting mechanism, 35, a camera, 36, a trolley rotating mechanism, 37, a self-centering clamping mechanism, 38, a flanged pipeline, 39, a three-jaw chuck or a two-jaw chuck.
Detailed Description
The following describes the embodiments of the present invention further with reference to the drawings and examples. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
Fig. 1 to 6 show an embodiment of a process for bending a flanged bend by using a numerical control tube bending machine, which sequentially comprises the following steps:
s1, clamping a flange type pipeline: one end with a flange of the flanged bent pipe is clamped on a self-centering clamping mechanism 37 of the servo trolley 1 of the pipe bending machine, and the straight pipe 31 part of the flanged pipeline is directly clamped by avoiding the flange during clamping;
s2, dynamically correcting the initial position of the flange hole site after clamping the flanged bent pipe:
s3, numerical control bending of the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on a numerical control pipe bending machine, and controlling the action of a servo trolley 1 of the pipe bending machine through the numerical control pipe bending program to realize three-dimensional bending of a pipe;
wherein the self-centering clamping mechanism 37 is arranged on a trolley rotating mechanism 36 of the servo trolley 1 of the pipe bending machine; the self-centering clamping mechanism 37 is provided with an L-shaped claw 4, and the self-centering clamping mechanism 37 directly clamps the straight pipe 31 part of the flanged pipeline by avoiding the pipe flange 32 through the L-shaped claw 4.
In this embodiment, the self-centering clamping mechanism 37 may take various forms, including but not limited to the following:
one of the constructions is a three-jaw self-centering chuck 39, in which the jaws on the chuck are adapted to L-shaped jaws 4 to directly clamp the straight pipe 31 portion of the flanged pipe while avoiding the flange.
And the second structure is that the self-centering clamping mechanism is a two-claw self-centering chuck 39, and the claws on the two-claw self-centering chuck are modified into L-shaped claws 4 so as to avoid flanges and directly clamp straight pipe parts of the flanged pipeline.
During clamping, the flange on the flanged pipeline transversely enters the L-shaped neutral gear of the L-shaped claw, and then the claw head of the L-shaped claw directly clamps the straight pipe 31 part of the flanged pipeline.
Thirdly, the self-centering clamping mechanism 37 directly clamps the straight pipe 31 of the flanged pipe 38 by adopting a large-opening self-centering strong clamping device to avoid the flange; the large-opening self-centering powerful clamping device comprises a rotary sleeve 2 arranged on a servo trolley 1 of a pipe bending machine, a hollow seat ring 3 fixed at the front end of the rotary sleeve 2, a plurality of L-shaped clamping claws 4 arranged at the front end of the hollow seat ring 3 and distributed at intervals along the circumferential direction, and a push-pull sleeve 5 arranged on the outer circle of the rotary sleeve 2 and capable of moving along the central axis direction of the rotary sleeve 2 so as to clamp the L-shaped clamping claws 4, wherein the L-shaped clamping claws 4 comprise rotating arms 6 and clamping blocks 7 connected to the front end of the rotating arms 6, the rotating arms 6 are rotatably connected with the front end of the rotary sleeve 2 through pin shafts 8, inner conical holes 9 are formed in the push-pull sleeve 5, outer conical holes 10 matched with the inner conical holes 9 in the push-pull sleeve 5 are formed in the outer side parts, far away from the central axis, of the rotating arms 6, and the clamping blocks 7 are positioned in the inner side parts, close to the central axis, of the rotating arms 6; the rotating arm 6 is connected with a spring 11 for automatically opening the L-shaped claw 4.
Preferably, the clamping block 7 of the L-shaped clamping jaw 4 is provided with an arc surface which is matched with the outer circle of the pipe 31.
In this embodiment, the front end of the hollow seat ring 3 is provided with a front flange 12, a plurality of positioning slots 13 parallel to the central axis are circumferentially formed in the outer circle of the front flange 12, and the rotating arms 6 of the L-shaped claws 4 are adapted to the positioning slots 13 and are in rotational connection with each other through the pin shafts 8.
Preferably, the number of the L-shaped claws 4 in the large-opening self-centering strong clamping device is four and the L-shaped claws are uniformly arranged at intervals along the circumferential direction.
The L-shaped claw 4 has a large rotation range, can realize the opening and closing of a large opening, and can be well suitable for shaking when the flanged pipeline 38 is hoisted, so that the flanged pipeline 38 is not easy to hurt and collide with hairs on one hand, and the clamping efficiency of the flanged pipeline 38 is improved on the other hand.
The large-opening self-centering powerful clamping device also utilizes the conical surface of the push-pull sleeve 5 to clamp the L-shaped clamping jaw 4, and the clamping jaw is mutually cooperated with the push-pull oil cylinder 24 and the lever type shifting fork 22 to realize powerful clamping under a compact structure; the push-pull oil cylinder 24 can meet the requirement of clamping force by using a small oil cylinder, and compared with the traditional clamping mode of matching a large-tonnage oil cylinder with a chuck, the manufacturing cost of the push-pull oil cylinder can be greatly reduced.
As a preferred scheme for realizing the automatic opening of the L-shaped clamping jaw by the large-opening self-centering strong clamping device in the embodiment, a clamping groove 14 is formed in the outer side part of the rear end of the rotating arm 6, which is far away from the central axis, the spring 11 is a tension spring, and the tension spring is sleeved on the clamping grooves 14 of the rotating arm 6 of the L-shaped clamping jaw 4 for clamping the flanged pipeline after being surrounded into a ring shape.
Preferably, an inner flange 15 is disposed at the inner hole position of the front end of the rotary sleeve 2, a rear flange 16 is disposed at the rear end of the hollow seat ring 3, and the rear flange 16 of the hollow seat ring 3 is fixedly connected with the inner flange 15 of the rotary sleeve 2 through bolts 17.
In this embodiment, the rotary sleeve 2 is connected to the output end of the worm gear box 18 of the servo trolley 1 of the pipe bender.
In this embodiment, an annular groove 19 is provided on the outer circle of the push-pull sleeve 5, a first support 20 is provided on the worm gear box 18, the first support 20 is rotatably connected with a lever type shifting fork 22 through a first hinge shaft 21, a roller 23 adapted to the annular groove 19 is rotatably provided at the front end of the lever type shifting fork 22, a push-pull oil cylinder 24 is further provided on the servo trolley 1 of the pipe bender, and a telescopic head 25 of the push-pull oil cylinder 24 is rotatably connected with the rear end of the lever type shifting fork 22 through a second hinge shaft 26.
In this embodiment, the servo trolley 1 of the pipe bender is provided with a second support 27, and the cylinder housing 28 of the push-pull cylinder 24 is rotatably connected to the second support 27 through a third hinge 29.
In this embodiment, the axes of the first hinge shaft 21, the second hinge shaft 26, the third hinge shaft 29 and the roller 23 are parallel to each other.
In this embodiment, the servo trolley 1 of the pipe bender is arranged on a moving guide rail 30 and moves on the moving guide rail 30 through a linear driving mechanism 33.
Preferably, in order to further expand the clamping range of the flanged pipe, a large chamfer is provided inside the clamping block 7 of the L-shaped claw 4.
During bending, an auxiliary mandrel can be inserted from the inner hole at the tail end of the servo trolley 1 of the pipe bending machine to the inner hole direction of the rotary sleeve 2 of the clamping device, and the auxiliary mandrel is positioned in the inner hole of the straight pipe 31 so as to realize auxiliary bending of the straight pipe 31.
Preferably, in the dynamic correction of the initial position of the flange hole position after clamping the flanged bent pipe in the step S2, the positions of a plurality of holes on the flange are identified by a visual identification device arranged on the numerical control pipe bender, and the correction of the initial angle position of the bending is performed according to the hole position errors of the plurality of holes on the identified flange.
More preferably, the dynamic correction of the initial position of the flange hole after clamping the flanged bent pipe in step S2 sequentially includes the following steps:
(1) And (3) identifying a single hole of the flange: setting a camera 35 coordinate system, and setting one single hole A and one single hole A on the pipe flange 32 of the flanged pipe 38 through a visual setting device;
(2) The rotation center position is set as follows: the trolley rotating mechanism 36 rotates to drive the flanged pipeline 38 on the self-centering clamping mechanism 37 to rotate together, the single hole A on the pipe flange 32 is rotated to a plurality of different positions, the coordinates of the single hole A at the different positions are detected by the vision identifying device, the position of the rotation center is calculated according to the coordinates of the single hole A at the plurality of different positions, and then an X-Y coordinate system taking the rotation center as an origin is established;
(3) Calculating a hole site angle correction amount: taking the single hole A and the single hole B which is arranged on the pipe flange 32 at 180 degrees with the single hole A, and calculating an included angle alpha between the single hole A and a Y axis according to the position of the single hole A in an X-Y coordinate system; then the trolley rotating mechanism 36 rotates 180 degrees, the single hole B is rotated to a corresponding position, the position of the rotated single hole B in an X-Y coordinate system is distinguished by a visual distinguishing device, and an included angle beta between the single hole B and a Y axis is calculated; taking the average value of alpha and beta, namely (alpha+beta)/2, as a hole site angle correction amount;
(4) Hole site correction: the trolley rotating mechanism 36 reversely rotates 180 degrees to reset the single hole B which is originally rotated 180 degrees, and then the trolley rotating mechanism 36 rotates to enable the single hole A to be positioned at the position with the included angle of (alpha+beta)/2 with the Y axis and serve as a correction position of the single hole A;
(5) Setting a bending initial angle: the trolley rotating mechanism 36 of the pipe bending machine rotates to rotate the position of the single hole A to a programmed starting angle, and then the pipe is automatically bent according to the bending program of the pipe bending machine.
It should be noted that, in practical use, the bolt holes on the flange of the flanged pipe 38 are basically even holes (such as four holes, six holes, eight holes, etc.). Therefore, in the hole position correction, two holes A and B which are 180 degrees away from each other are adopted to carry out visual identification detection and correction after rotating 180 degrees. If odd holes or other non-uniformly distributed special distribution holes occur, two holes with the farthest distance on the pipe flange 32 can be selected, according to the theoretical design included angles of the two holes, a corresponding theoretical design included angle is turned during hole position correction, corresponding alpha and beta angle values are obtained through visual identification and detection, and then hole position correction is performed.
Theoretically, the position of the rotation center can be calculated by knowing the coordinates of the three positions of the single hole a. However, in order to improve the accuracy of the identification of the rotation center position, the following further improvements may be adopted: in the step (2), the single hole a is rotated to seven different positions on the pipe flange 32, and the rotation center position is calculated from coordinates of the single hole a at the seven different positions.
In order to improve the bending precision, the scheme adopted as a further improvement of the embodiment is as follows: before bending the flanged pipe 38 in batches, a bending test is performed in advance, the flanged pipe 38 manufactured by the bending test is scanned by adopting a three-dimensional laser scanner to form a three-dimensional solid model of the flanged pipe 38, the scanned solid model is imported into three-dimensional design software and is compared with a three-dimensional design theoretical model of the flanged pipe 38 to obtain actual bending errors of each bending part on the flanged pipe 38, and the actual bending errors are written into a bending program as compensation quantities to form a bending program with bending error compensation; in formally bending the flanged pipe 38, the bending process with bend error compensation is used for bending.
When the test is actually carried out, the bending test can be respectively carried out section by section according to the number of the bent sections of the pipeline in sequence, and after the bending test and the program compensation of the former section are finished, the bending test and the program compensation of the latter section are carried out until all the bending part tests and the program compensation are finished. Its advantage is high correction accuracy, but the number of tests that need to be carried out is more.
In order to achieve both correction precision and test frequency reduction, the preferred scheme is to perform local comparison for each bending node after a one-time bending test; that is, when there are a plurality of bending nodes for the flanged pipe 38, the bending errors at the positions of the bending nodes are obtained by taking each bending node in the three-dimensional design software and performing the comparison, and then the bending errors at the positions of the bending nodes are written into the bending program as compensation amounts, thereby forming the bending program with bending error compensation.
The numerical control pipe bender in the embodiment comprises a pipe bender servo trolley 1, a trolley rotating mechanism 36 arranged on the pipe bender servo trolley 1, a self-centering clamping mechanism 37 connected to the trolley rotating mechanism 36 and used for clamping a flanged pipeline, and a visual identification device arranged beside the self-centering clamping mechanism 37 and used for detecting a flange hole position on the flanged pipeline; the visual identification device comprises a camera 35 and a visual identification system connected with the camera 35, wherein the visual identification system and the camera 35 are respectively connected with a control system of the numerical control pipe bending machine.
Preferably, the camera 35 is arranged on the lifting mechanism 34, and the lifting mechanism 34 is connected with a control system of the numerical control pipe bending machine.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the scope of the invention.
Claims (7)
1. A process for bending a flanged bent pipe by adopting a numerical control pipe bending machine is characterized by comprising the following steps in sequence:
s1, clamping a flange type pipeline: one end with a flange of the flanged bent pipe is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bending machine, and the straight pipe part of the flanged pipeline is directly clamped by avoiding the flange during clamping;
s2, dynamically correcting the initial position of the flange hole site after clamping the flanged bent pipe:
s3, numerical control bending of the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on a numerical control pipe bending machine, and controlling the action of a servo trolley of the pipe bending machine through the numerical control pipe bending program to realize three-dimensional bending of a pipe;
the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bending machine; the self-centering clamping mechanism is provided with an L-shaped claw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped claw;
the self-centering clamping mechanism is a three-jaw self-centering chuck or a two-jaw self-centering chuck, and jaws on the three-jaw self-centering chuck or the two-jaw self-centering chuck are changed into L-shaped jaws so as to avoid flanges and directly clamp straight pipe parts of flanged pipelines.
2. The process for bending a flanged bent pipe by using a numerical control pipe bender according to claim 1, wherein the flange on the flanged pipe transversely enters the L-shaped neutral gear of the L-shaped claw during clamping, and then the straight pipe part of the flanged pipe is directly clamped by the claw head of the L-shaped claw.
3. The process for bending a flanged bend by using a numerical control tube bending machine according to claim 1, wherein in the dynamic correction of the initial position of the flanged hole position after clamping the flanged bend in step S2, the positions of the plurality of holes on the flange are identified by a visual identification device arranged on the numerical control tube bending machine, and correction of the initial bending angle position is performed according to the identified hole position errors of the plurality of holes on the flange.
4. The process for bending a flanged bent pipe by using a numerical control pipe bender according to claim 3, wherein the dynamic correction of the initial position of the flange hole after clamping the flanged bent pipe in step S2 sequentially comprises the following steps:
(1) And (3) identifying a single hole of the flange: setting a camera coordinate system, and identifying one single hole A and one single hole A on a pipe flange of the flange type pipeline through a visual identification device;
(2) Rotation center position identification: the trolley rotating mechanism rotates to drive the flanged pipeline on the self-centering clamping mechanism to rotate together, the single hole A on the pipe flange is rotated to a plurality of different positions, the coordinates of the single hole A at the different positions are detected by the visual recognition device, the position of a rotation center is calculated according to the coordinates of the single hole A at the plurality of different positions, and then an X-Y coordinate system taking the rotation center as an origin is established;
(3) Calculating a hole site angle correction amount: taking the single hole A and the single hole B which is arranged on the pipe flange and is 180 degrees away from the single hole A, and calculating an included angle alpha between the single hole A and a Y axis according to the position of the single hole A in an X-Y coordinate system; then the trolley rotating mechanism rotates 180 degrees, the single hole B rotates to a corresponding position, the position of the single hole B in an X-Y coordinate system after rotation is identified by a visual identification device, and an included angle beta between the single hole B and a Y axis is calculated; taking the average value of alpha and beta, namely (alpha+beta)/2, as a hole site angle correction amount;
(4) Hole site correction: the trolley rotating mechanism reversely rotates 180 degrees to reset the single hole B which is originally rotated 180 degrees, and then the trolley rotating mechanism rotates to enable the single hole A to be located at the position with the included angle (alpha+beta)/2 with the Y axis and serve as a correction position of the single hole A;
(5) Setting a bending initial angle: the trolley rotating mechanism of the pipe bending machine rotates to rotate the position of the single hole A to a starting angle set by a program, and then the pipe is automatically bent according to a bending program of the pipe bending machine.
5. The process for bending a flanged bent pipe by using a numerical control pipe bender according to claim 4, wherein in the step (2) of identifying the rotation center position, the single hole a on the pipe flange is rotated to seven different positions, and the rotation center position is calculated according to the coordinates of the single hole a at the seven different positions.
6. The process for bending a flanged pipe by using a numerical control pipe bender according to claim 5, wherein a bending test is performed in advance before the flanged pipe is bent in batches, the flanged pipe manufactured by the bending test is scanned by using a three-dimensional laser scanner to form a three-dimensional solid model of the flanged pipe, the scanned solid model is imported into three-dimensional design software and is compared with a three-dimensional design theoretical model of the flanged pipe to obtain actual bending errors of each bending part on the flanged pipe, and the actual bending errors are written into a bending program as compensation amounts to form a bending program with bending error compensation; and when the flange-type pipeline is bent formally, bending is performed by using the bending program with bending error compensation.
7. The process for bending a flanged pipe using a numerical control pipe bender according to claim 6, wherein when the flanged pipe has a plurality of bending nodes, the bending errors of the positions of the bending nodes are obtained by respectively comparing the bending nodes in three-dimensional design software.
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| DE2626202C2 (en) * | 1976-06-11 | 1992-10-29 | Rigobert Dipl.-Ing. 5000 Köln Schwarze | Tube bending machine |
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| DE102018108863A1 (en) * | 2018-04-13 | 2019-10-17 | Wafios Aktiengesellschaft | Bending device for elongated workpieces |
| CN211866227U (en) * | 2020-02-25 | 2020-11-06 | 安徽德系重工科技有限公司 | Clamping and bending integrated mechanism for welding flange pipe for ship before bending and pipe bending machine |
| CN211915102U (en) * | 2020-03-26 | 2020-11-13 | 大连船舶重工集团有限公司 | Pipe flange single-hole positive positioning die for numerical control pipe bending machine with welding before bending |
| CN112222250A (en) * | 2020-09-06 | 2021-01-15 | 王允 | Automatic pipe bending machine |
| CN113118266B (en) * | 2021-04-13 | 2023-03-07 | 江阴市宏业机械制造有限公司 | Numerical control pipe bender capable of dynamically correcting hole positions through visual detection and pipe bending method |
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