CN113477818A - Pipe bending process for bending flanged bent pipe by using numerical control pipe bender - Google Patents
Pipe bending process for bending flanged bent pipe by using numerical control pipe bender Download PDFInfo
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- CN113477818A CN113477818A CN202110697731.6A CN202110697731A CN113477818A CN 113477818 A CN113477818 A CN 113477818A CN 202110697731 A CN202110697731 A CN 202110697731A CN 113477818 A CN113477818 A CN 113477818A
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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
Abstract
The invention discloses a pipe bending process for bending a flanged bent pipe by adopting a numerical control pipe bender, which sequentially comprises the following steps: s1, clamping of the flanged pipeline: one end of the flanged bent pipe with the flange is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bender; s2, dynamically correcting the initial position of the flange hole position after clamping the flanged bent pipe: s3, carrying out numerical control bending on the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on the 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 the pipe; the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bender; the self-centering clamping mechanism is provided with an L-shaped clamping jaw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped clamping jaw. 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 pipe bending 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 from a pipe in a bending deformation mode.
In the prior art, a typical numerical control pipe bender comprises a pipe bender main unit (servo trolley), wherein the pipe bender main unit is integrally arranged on a movable guide rail and is driven by a servo motor to move on the guide rail; the main machine of the pipe bender 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 the pipe is bent, the pipe is clamped by the chuck, and the rotating angle and the moving distance of the trolley rotating mechanism are controlled by the numerical control system under the matching of a pipe bending die, so that the three-dimensional bending of the pipe is realized.
The bending of pipes is classified into bending of pipes without flanges and bending of pipes with flanges according to the bending process. The pipe without the flange has no flange at the end part of the pipe, and the pipe is directly bent by clamping the pipe part by a chuck during bending; the flanged 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 during bending.
The numerical control pipe bender is commonly used in shipyards. At present, most of units of a shipyard adopt a process of bending a pipe firstly and welding a flange secondly. The process has low efficiency, more labor and higher requirement on workers. A small part of shipyards adopt a process of welding before bending after accumulating the bending experience of the pipes for many years, but are influenced by factors such as the rotation precision of a numerical control pipe bender, unreliable clamping outside a clamping flange of a servo trolley, large error of positioning the flange by a pin shaft, errors of welding the flange on a straight pipe, non-fit between the end face of the flange and the end face of the trolley, deformation of welding the flange and the straight pipe and the like, so that the error ratio is large, the flange cannot rotate to a required position, and the bent flange pipe has large deviation and cannot be used.
In the prior art, for bending a pipe with a flange, in order to make the circumferential position of a bolt hole on the flange accurate relative to the three-dimensional bent shape position of the pipe, a positioning pin shaft is usually arranged on a chuck, and one bolt hole on the flange is sleeved in 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 with flange pipe has the following problems:
first, due to a large gap between the flange and the pipe, the flange and the pipe are liable to be eccentric and inclined at the time of assembly, so that the bolt hole positions on the flange, particularly the circumferential positions, are largely deviated from the center of the pipe; if the circumferential position of the flange is determined by only single-hole positioning, a large circumferential position error of another single hole arranged at 180 degrees relative to the single hole can be caused, and the subsequent pipeline butt joint assembly after the three-dimensional bending of the pipe is difficult or even cannot be assembled.
Secondly, the rotating mechanism of the servo trolley of the pipe bender also has a certain rotating error, which can cause the circumferential error of the bolt hole position on the flange relative to the three-dimensional bent pipe, thus causing the pipeline butt joint assembly to be difficult and even causing the phenomenon of incapability of assembling.
Thirdly, when the infrared hole measurement positioning is adopted, only a single hole can be detected, and the accurate positioning cannot be realized due to the influence of factors such as a punching error, a hole position relative position error and a flange welding error.
Disclosure of Invention
In order to solve the problems, the invention provides a pipe bending process for bending a flanged bent pipe by adopting a numerical control pipe bending machine, which improves the bending precision of the flanged pipeline. The specific technical scheme is as follows:
a pipe bending process for bending a flanged bent pipe by using a numerical control pipe bender sequentially comprises the following steps:
s1, clamping of the flanged pipeline: one end of the flanged bent pipe with the flange is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bender, 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 position after clamping the flanged bent pipe:
s3, carrying out numerical control bending on the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on the 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 the pipe;
the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bender; the self-centering clamping mechanism is provided with an L-shaped clamping jaw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped clamping jaw.
In the present invention, the self-centering clamping mechanism can adopt various structural forms, including but not limited to the following structures:
one of the structures, from centering fixture be three-jaw from centering chuck, three-jaw from the jack catch on the centering chuck is reformed transform into L type jack catch in order to avoid the flange and directly carry the straight tube portion of taking flange type pipeline.
And the second structure is that the self-centering clamping mechanism is a two-jaw self-centering chuck, and the two jaws are reformed into L-shaped jaws to avoid the flange and directly clamp the straight pipe part of the flanged pipeline from the jaws on the self-centering chuck.
During clamping, the flange on the flanged pipeline transversely enters the L-shaped neutral gear of the L-shaped clamping jaw, and then the straight pipe part of the flanged pipeline is directly clamped through the clamping jaw head of the L-shaped clamping jaw.
Thirdly, 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 rotary sleeve arranged on a servo trolley of the pipe bender, a hollow seat ring fixed at the front end of the rotary sleeve, a plurality of L-shaped clamping jaws arranged at the front end of the hollow seat ring and distributed at intervals along the circumferential direction and used for clamping flanged pipelines, and a push-pull sleeve arranged on the outer circle of the rotary sleeve and capable of moving along the central axis direction of the rotary sleeve to clamp the L-shaped clamping jaws, the L-shaped clamping jaw comprises a rotating arm and a clamping block connected to the front end of the rotating arm, the rotating arm is rotatably connected with the front end of the rotating sleeve through a pin shaft, the push-pull sleeve is provided with an inner taper hole, the outer side part of the rotating arm far away from the central axis is provided with an outer conical surface matched with the inner conical hole on the push-pull sleeve, and the clamping block is positioned on the inner side part of the rotating arm close to the central axis; and the rotating arm is connected with a spring for automatically opening the L-shaped clamping jaw.
Preferably, the clamping block of the L-shaped clamping jaw is provided with an arc surface matched with the excircle 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 in 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 rotatably connected through the pin shafts.
Preferably, the number of the L-shaped clamping jaws in the large-opening self-centering powerful clamping device is four, and the L-shaped clamping jaws are uniformly arranged at intervals in the circumferential direction.
The L-shaped clamping jaw has a large rotation range, can be opened and closed in a large opening degree, and can be well suitable for shaking during hoisting of flanged pipelines, so that pipes are not easy to damage and touch hairs on one hand, and the efficiency of clamping flanged pipelines on the other hand is improved.
The large-opening self-centering powerful clamping device also realizes the clamping of the L-shaped clamping jaw by utilizing the conical surface of the push-pull sleeve, and the clamping of the L-shaped clamping jaw is realized by the mutual cooperation of the large-opening self-centering powerful clamping device, the push-pull sleeve, the push-pull oil cylinder and the lever type shifting fork, so that the powerful clamping under a compact structure is realized; 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 that a large-tonnage oil cylinder is matched with a chuck, the manufacturing cost of the push-pull oil cylinder can be greatly reduced.
As a preferred scheme for realizing automatic opening of the L-shaped jaws by the large-opening-degree self-centering powerful clamping device, a clamping groove is formed in the outer side part of the rear end of the rotating arm, which is far away from the central axis, the spring is a tension spring, and the tension spring is encircled into a ring shape and then is simultaneously sleeved on the clamping grooves of the rotating arms, which are used for clamping the L-shaped jaws with the flange type pipelines.
Preferably, an inner flange is arranged at the inner hole part at the front end of the rotating 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 rotating sleeve through bolts.
In the invention, the rotary sleeve is connected with the output end of a worm gear transmission box of the servo trolley of the pipe bender.
According to the pipe bender servo trolley, an annular groove is formed in the outer circle of the push-pull sleeve, a first support is arranged on the worm gear transmission box, the first support is rotatably connected with a lever type shifting fork through a first hinge shaft, a roller matched with the annular groove is rotatably arranged at the front end of the lever type shifting fork, a push-pull oil cylinder is further arranged on the pipe bender servo trolley, and a telescopic head of the push-pull oil cylinder is rotatably connected with the rear end of the lever type shifting fork through a second hinge shaft.
According to the invention, a second support is arranged on the servo trolley of the pipe bender, and an oil cylinder shell of the push-pull oil cylinder is rotatably connected to the second support through a third hinge shaft.
In the invention, the axes of the first hinge shaft, the second hinge shaft, the third hinge shaft and the roller are parallel to each other.
In the invention, the pipe bender servo trolley is arranged on the movable guide rail and moves on the movable 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 bender to the inner hole 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 hole site of the flange after the clamped flanged bend pipe of step S2, the positions of the plurality of holes on the flange are identified by the visual identification device disposed on the nc pipe bender, and the correction of the bending start angle position is performed according to the hole site errors of the plurality of holes on the identified flange.
More preferably, the dynamic correction of the initial position of the flange hole site after the flanged elbow is clamped in step S2 sequentially includes the following steps:
(1) identifying a single hole of the flange: setting a camera coordinate system, and setting and identifying one of the single holes A and the positions on the pipe flange of the flanged pipeline through a visual identification device;
(2) the rotation center position is set: the trolley rotating mechanism rotates to drive a 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, coordinates of the single hole A at different positions are obtained through detection of a vision identification device, the position of a rotating center is calculated according to the coordinates of the single hole A at the different positions, and then an X-Y coordinate system with the rotating center as an origin is established;
(3) calculating the correction value of the hole position angle: taking the single hole A and another single hole B which is arranged on the pipe flange and forms an angle of 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 rotates 180 degrees, the single hole B is rotated to a corresponding position, the position of the single hole B in the X-Y coordinate system after the single hole B rotates is set by the vision setting device, and the included angle beta between the single hole B and the Y axis is calculated; taking the average value of alpha and beta, namely (alpha + beta)/2 as the hole site angle correction quantity;
(4) hole site correction: the trolley rotating mechanism rotates in the reverse direction for 180 degrees, so that the original single hole B rotating for 180 degrees is reset, and then the trolley rotating mechanism rotates to enable the single hole A to be positioned at a position which has an included angle (alpha + beta)/2 with the Y axis and is used as a correction position of the single hole A;
(5) setting a bending initial angle: and the trolley rotating mechanism of the pipe bender rotates to rotate the position of the single hole A to the initial angle set by the program, and then the pipe is bent automatically according to the bending program of the pipe bender.
It should be pointed out that the bolt holes on the pipe flange of the flanged pipeline used in reality are basically even holes (such as four-hole uniform distribution, six-hole uniform distribution, eight-hole uniform distribution and the like) which are uniformly distributed. Therefore, when the hole positions are corrected, two holes A and B which are 180 degrees relative to each other are adopted, and the holes A and B are rotated by 180 degrees to perform visual identification detection and correction. If odd holes or other non-uniform special distribution holes occur, two holes with the farthest distance on the pipe flange can be selected, a corresponding theoretical design included angle is rotated when hole position correction is carried out according to the theoretical design included angles of the two holes, corresponding alpha and beta angle values are obtained through visual identification detection, and then hole position correction is carried out.
Theoretically, the position of the center of rotation 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 position of the rotation center, the following further improvements may be adopted: and (3) in the step (2) of setting the rotation center position, rotating the single hole A on the pipe flange to seven different positions, and calculating the rotation center position according to the coordinates of the single hole A at the seven different positions.
In order to improve the bending precision, the scheme of the invention is further improved as follows: before bending the flanged pipelines in batches, performing a bending test in advance, scanning the flanged pipelines manufactured by the bending test by using a three-dimensional laser scanner to form a three-dimensional solid model of the flanged pipelines, guiding the scanned solid model into three-dimensional design software, comparing the scanned solid model with a three-dimensional design theoretical model of the flanged pipelines to obtain actual bending errors of all bending parts on the flanged pipelines, and writing the actual bending errors into a bending program by using the actual bending errors as compensation quantities to form the bending program with bending error compensation; and when the flanged pipeline is formally bent, the bending procedure with the bending error compensation is used for bending.
During actual test, the bending test can be performed section by section according to the number of sections of the bent pipeline, and after the bending test and program compensation of the previous section are completed, the bending test and program compensation for the next section are performed until all the bending part tests and program compensation are completed. Its advantages are high correctness, and more tests.
In order to take the correction precision and reduce the test times into consideration, the preferable scheme is that after a one-time bending test is adopted, local comparison is carried out on each bending node; when the flanged pipeline has a plurality of bending nodes, the bending nodes are respectively taken from the three-dimensional design software to be compared to obtain the bending error of each bending node position, and then the bending error of each bending node position is written into a bending program as a compensation quantity to form the bending program with the 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 the flange hole position on the flanged pipeline; the vision identification device comprises a camera and a vision identification system connected with the camera, and the vision identification system and the camera are respectively connected with a control system of the numerical control pipe bender.
Preferably, the camera is arranged on a lifting mechanism, and the lifting mechanism is connected with a control system of the numerical control pipe bender.
The invention has the beneficial effects that:
firstly, according to the pipe bending process for bending the flanged bend pipe by adopting the numerical control pipe bending machine, the pipe is clamped by adopting the L-shaped clamping jaws, the L-shaped clamping jaws avoid the flange and directly clamp the straight pipe part of the flanged pipeline, and the defects of large clamping deflection deviation error and poor pipe bending precision caused by the fact that the traditional pipe bending machine directly clamps the pipe flange are overcome.
Secondly, according to the pipe bending process for bending the flanged bend pipe by adopting the numerical control pipe bending machine, the hole position on the flange is set through the visual recognition system, the dynamic correction of the initial position of the hole position of the flange is carried out according to the error of the hole position of the set flange, the circumferential position of the pipe flange is corrected to an optimal angle, the optimal position arrangement of the circumferential hole position on the flange relative to the three-dimensional bent pipeline is realized, the pipe bending precision is improved, and the defect that the installation is difficult due to the large circumferential error of the hole position on the flange formed by adopting single-hole positioning in the traditional flanged pipeline bending process is overcome.
Thirdly, the pipe bending process for bending the flanged bent pipe by the numerical control pipe bending machine adopts the large-opening self-centering powerful clamping device to clamp the pipeline, 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 when the pipe flange is clamped by the traditional bending numerical control pipe bending machine is overcome; compared with the traditional mode of clamping the outer circle of the flange, the mode of directly clamping the outer diameter of the pipe does not generate clamping deflection, so that the quality of three-dimensional bending of the pipe can be improved.
Fourthly, the pipe bending process for bending the flanged bent pipe by the numerical control pipe bending machine adopts the visual recognition system to recognize and detect the hole position of the flange, and the detection after replacing the flanges with different specifications is not influenced (the flanges with different specifications have different hole diameters, different hole circumferential diameters and different flange thicknesses).
Fifthly, the pipe bending process for bending the flanged bent 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 pipeline processing process of a shipyard, realizes zero-allowance accurate blanking, automatic pipe coding, automatic straight pipe flange welding and automatic pipe bending of the numerical control pipe bending machine, can realize workshop intelligent production, greatly saves labor and improves the production efficiency. The visual identification system is not influenced by different flange specifications, and the system can be completely covered.
Drawings
FIG. 1 is a schematic view of a pipe bending process for bending a flanged pipe by using a CNC pipe bender according to the present invention;
FIG. 2 is a schematic diagram of dynamic hole position correction in a pipe bending process of bending a flanged pipe by using a CNC pipe bender according to the present invention;
FIG. 3 is a schematic structural diagram of a numerically controlled pipe bender with a large-opening self-centering powerful clamping device;
FIG. 4 is a schematic structural diagram of a self-centering clamping mechanism adopting 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 powerful clamping device in fig. 5 after the L-shaped jaws are opened (in the figure, large chamfers are arranged on the inner sides of the clamping blocks of the L-shaped jaws).
In the figure: 1. the pipe bender servo trolley comprises a pipe bender servo trolley, a pipe bender servo trolley, a pipe bender servo trolley, a pipe bender, a pipe bender, a pipe bender, a pipe bender, a pipe bender, a pipe bender, a pipe bender, A three-jaw chuck or a two-jaw chuck.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Fig. 1 to 6 show an embodiment of a pipe bending process for bending a flanged pipe by using a numerically controlled pipe bender according to the present invention, which sequentially comprises the following steps:
s1, clamping of the flanged pipeline: one end of the flanged bent pipe with the flange is clamped on a self-centering clamping mechanism 37 of the servo trolley 1 of the pipe bender, 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 position after clamping the flanged bent pipe:
s3, carrying out numerical control bending on the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on the numerical control pipe bending machine, and controlling the action of the servo trolley 1 of the pipe bending machine through the numerical control pipe bending program to realize three-dimensional bending of the pipe;
the self-centering clamping mechanism 37 is arranged on a trolley rotating mechanism 36 of the pipe bender servo trolley 1; be provided with L type jack catch 4 on the fixture 37 of feeling relieved from feeling relieved, from feeling relieved fixture 37 through L type jack catch 4 avoids flange 32 and directly presss from both sides the straight tube 31 part of flanged type pipeline.
In this embodiment, the self-centering clamping mechanism 37 may take various configurations, including but not limited to the following:
one of the structures, from centering fixture be three-jaw from centering chuck 39, three-jaw from centering chuck's last jack catch is reformed transform into L type jack catch 4 and is in order to avoid the flange and directly carry the straight tube 31 part of flanged type pipeline.
And the second structure is that the self-centering clamping mechanism is a two-jaw self-centering chuck 39, and the jaws on the two-jaw self-centering chuck are reformed into L-shaped jaws 4 to avoid flanges and directly clamp the straight pipe part of the flanged pipeline.
During clamping, the flange on the flanged pipeline transversely enters the L-shaped neutral gear of the L-shaped clamping jaw, and then the straight pipe 31 part of the flanged pipeline is directly clamped through the clamping jaw head of the L-shaped clamping jaw.
Thirdly, the self-centering clamping mechanism 37 adopts a large-opening self-centering powerful clamping device to avoid the flange and directly clamp the straight pipe 31 part of the flanged pipeline 38; the large-opening self-centering powerful clamping device comprises a rotary sleeve 2 arranged on a servo trolley 1 of the pipe bender, a hollow seat ring 3 fixed at the front end of the rotary sleeve 2, a plurality of L-shaped claws 4 arranged at the front end of the hollow seat ring 3 and distributed at intervals along the circumferential direction and used for clamping flanged pipelines, and a push-pull sleeve 5 arranged on the excircle of the rotary sleeve 2 and capable of moving along the central axis direction of the rotary sleeve 2 to clamp the L-shaped claws 4, wherein the L-shaped claws 4 comprise rotary arms 6 and clamping blocks 7 connected to the front ends of the rotary arms 6, the rotary arms 6 are rotatably connected with the front end of the rotary sleeve 2 through pin shafts 8, inner conical holes 9 are arranged on the push-pull sleeve 5, outer conical surfaces 10 matched with the inner conical holes 9 on the push-pull sleeve 5 are arranged on the outer side parts, far away from the central axis, of the rotary arms 6, the clamping block 7 is positioned on the inner side part of the rotating arm 6 close to the central axis; and a spring 11 for automatically opening the L-shaped clamping jaw 4 is connected to the rotating arm 6.
Preferably, the clamping block 7 of the L-shaped clamping jaw 4 is provided with a cambered surface matched with the outer circle of the pipe 31.
In this embodiment, the front end of hollow seat circle 3 is provided with front flange 12, a plurality of quantity is on a parallel with along circumference on the excircle of front flange 12 the constant head tank 13 of the central axis, the rotor arm 6 of L type jack catch 4 with constant head tank 13 looks adaptation and through round pin axle 8 realizes rotating the connection.
Preferably, the number of the L-shaped clamping jaws 4 in the large-opening self-centering powerful clamping device is four, and the L-shaped clamping jaws are uniformly arranged at intervals in the circumferential direction.
The L-shaped clamping jaw 4 is large in rotation range and can be opened and closed in a large opening degree, so that the L-shaped clamping jaw can be well adapted to shaking of the flanged pipeline 38 during hoisting, the flanged pipeline 38 is not prone to being damaged and broken 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 device 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 can be greatly reduced.
As an optimal scheme for realizing automatic opening of the L-shaped jaws by the large-opening self-centering powerful clamping device in this embodiment, the rear end of the rotating arm 6 is far away from the outside of the central axis, and the clamping groove 14 is formed in the outer side of the central axis, and the spring 11 is a tension spring which is surrounded into a ring shape and then sleeved outside the clamping grooves 14 of the rotating arms 6, the number of which is used for clamping the L-shaped jaws 4 with flange-type pipelines.
Preferably, an inner flange 15 is arranged at an inner hole part at the front end of the rotating sleeve 2, a rear flange 16 is arranged 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 rotating sleeve 2 through bolts 17.
In this embodiment, the rotary sleeve 2 is connected to an output end of a worm gear box 18 of the pipe bender servo trolley 1.
In this embodiment, an annular groove 19 is formed in an outer circle of the push-pull sleeve 5, a first support 20 is arranged on the worm gear transmission case 18, the first support 20 is rotatably connected with a lever-type shifting fork 22 through a first hinge shaft 21, a roller 23 matched with the annular groove 19 is rotatably arranged at the front end of the lever-type shifting fork 22, a push-pull oil cylinder 24 is further arranged on the pipe bender servo trolley 1, 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 shaft 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 bending machine servo trolley 1 is disposed on the moving rail 30 and is moved on the moving rail 30 by the linear driving mechanism 33.
Preferably, in order to further expand the clamping range of the flanged pipeline, a large chamfer is arranged inside the clamping block 7 of the L-shaped clamping jaw 4.
During bending, an auxiliary mandrel can be inserted from the inner hole of the tail end of the servo trolley 1 of the pipe bending machine to the inner hole of the rotary sleeve 2 of the clamping device, and the auxiliary mandrel is positioned in the inner hole of the pipe 31, so that auxiliary bending of the pipe 31 is realized.
Preferably, in the dynamic correction of the initial position of the hole site of the flange after the clamped flanged bend pipe of step S2, the positions of the plurality of holes on the flange are identified by the visual identification device disposed on the nc pipe bender, and the correction of the bending start angle position is performed according to the hole site errors of the plurality of holes on the identified flange.
More preferably, the dynamic correction of the initial position of the flange hole site after the flanged elbow is clamped in step S2 sequentially includes the following steps:
(1) identifying a single hole of the flange: setting a coordinate system of a camera 35, and setting one of the single holes A and the positions on the pipe flange 32 of the flanged pipeline 38 through a visual identification device;
(2) the rotation center position is set: 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, coordinates of the single hole A at different positions are obtained through detection of a vision identification device, the position of a rotating center is calculated according to the coordinates of the single hole A at the different positions, and then an X-Y coordinate system with the rotating center as an origin is established;
(3) calculating the correction value of the hole position angle: taking the single hole A and another single hole B which is arranged on the pipe flange 32 and forms an angle of 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 single hole B in the X-Y coordinate system after the single hole B rotates is set by the vision setting device, and the included angle beta between the single hole B and the Y axis is calculated; taking the average value of alpha and beta, namely (alpha + beta)/2 as the hole site angle correction quantity;
(4) hole site correction: the trolley rotating mechanism 36 rotates in the reverse direction for 180 degrees, so that the original single hole B rotating for 180 degrees is reset, and then the trolley rotating mechanism 36 rotates to enable the single hole A to be positioned at a position which has an included angle (alpha + beta)/2 with the Y axis and is used as a correction position of the single hole A;
(5) setting a bending initial angle: the trolley rotating mechanism 36 of the pipe bender rotates to rotate the position of the single hole A to the initial angle set by the program, and then the bending of the pipeline is automatically carried out according to the bending program of the pipe bender.
It should be noted that the bolt holes on the pipe flanges of the flanged pipeline 38 used in the actual implementation are basically even holes (such as four holes, six holes, eight holes, etc.) which are uniformly distributed. Therefore, when the hole positions are corrected, two holes A and B which are 180 degrees relative to each other are adopted, and the holes A and B are rotated by 180 degrees to perform visual identification detection and correction. If odd holes or other non-uniform special distribution holes occur, two holes with the farthest distance on the pipe flange 32 can be selected, a corresponding theoretical design included angle is rotated when hole position correction is carried out according to the theoretical design included angles of the two holes, corresponding alpha and beta angle values are obtained through visual identification detection, and then hole position correction is carried out.
Theoretically, the position of the center of rotation 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 position of the rotation center, the following further improvements may be adopted: in the step (2), the rotation center position is set, the single hole a on the pipe flange 32 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.
In order to improve the bending precision, the scheme of further improvement as the embodiment is as follows: before bending the flanged pipelines 38 in batches, performing a bending test in advance, scanning the flanged pipelines 38 manufactured by the bending test by using a three-dimensional laser scanner to form a three-dimensional solid model of the flanged pipelines 38, introducing the scanned solid model into three-dimensional design software, comparing the scanned solid model with a three-dimensional design theoretical model of the flanged pipelines 38 to obtain actual bending errors of all bending parts on the flanged pipelines 38, and writing the actual bending errors into a bending program by using the actual bending errors as compensation quantities to form the bending program with bending error compensation; in the bending of the flanged pipe 38, the bending is performed by using the bending process with the bending error compensation.
During actual test, the bending test can be performed section by section according to the number of sections of the bent pipeline, and after the bending test and program compensation of the previous section are completed, the bending test and program compensation for the next section are performed until all the bending part tests and program compensation are completed. Its advantages are high correctness, and more tests.
In order to take the correction precision and reduce the test times into consideration, the preferable scheme is that after a one-time bending test is adopted, local comparison is carried out on each bending node; that is, when there are a plurality of bending nodes in the flanged pipeline 38, the bending nodes are respectively compared in the three-dimensional design software to obtain the bending error of each bending node position, and then the bending error of each bending node position is written into the bending program as a compensation amount to form 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 the 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, and the visual identification system and the camera 35 are respectively connected with a control system of the numerical control pipe bender.
Preferably, the camera 35 is disposed on the lifting mechanism 34, and the lifting mechanism 34 is connected to a control system of the numerically controlled pipe bender.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A pipe bending process for bending a flanged bent pipe by adopting a numerical control pipe bender is characterized by sequentially comprising the following steps of:
s1, clamping of the flanged pipeline: one end of the flanged bent pipe with the flange is clamped on a self-centering clamping mechanism of a servo trolley of the pipe bender, 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 position after clamping the flanged bent pipe:
s3, carrying out numerical control bending on the dynamically corrected flanged bent pipe: starting a numerical control pipe bending program on the 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 the pipe;
the self-centering clamping mechanism is arranged on a trolley rotating mechanism of the servo trolley of the pipe bender; the self-centering clamping mechanism is provided with an L-shaped clamping jaw, and the self-centering clamping mechanism directly clamps a straight pipe part of a flanged pipeline by avoiding a flange through the L-shaped clamping jaw.
2. The pipe bending process according to claim 1, wherein the self-centering clamping mechanism is a three-jaw self-centering chuck, and the jaws of the three-jaw self-centering chuck are modified to be L-shaped jaws to avoid the flange and directly clamp the straight pipe portion of the flanged pipe.
3. The pipe bending process according to claim 1, wherein the self-centering clamping mechanism is a two-jaw self-centering chuck, and the jaws of the two-jaw self-centering chuck are modified into L-shaped jaws to avoid the flange and directly clamp the straight pipe portion of the flanged pipe.
4. The pipe bending process for bending the flanged pipe by using the numerical control pipe bending machine according to claim 2 or 3, wherein the flange on the flanged pipe transversely enters the L-shaped space of the L-shaped jaw during clamping, and then the straight pipe part of the flanged pipe is directly clamped by the jaw head of the L-shaped jaw.
5. The pipe bending process for bending a flanged pipe by using a numerically controlled pipe bender according to claim 1, wherein the self-centering clamping mechanism employs a large-opening self-centering powerful clamping device to avoid the flange and directly clamp the straight pipe portion of the flanged pipe; the large-opening self-centering powerful clamping device comprises a rotary sleeve arranged on a servo trolley of the pipe bender, a hollow seat ring fixed at the front end of the rotary sleeve, a plurality of L-shaped clamping jaws arranged at the front end of the hollow seat ring and distributed at intervals along the circumferential direction and used for clamping flanged pipelines, and a push-pull sleeve arranged on the outer circle of the rotary sleeve and capable of moving along the central axis direction of the rotary sleeve to clamp the L-shaped clamping jaws, the L-shaped clamping jaw comprises a rotating arm and a clamping block connected to the front end of the rotating arm, the rotating arm is rotatably connected with the front end of the rotating sleeve through a pin shaft, the push-pull sleeve is provided with an inner taper hole, the outer side part of the rotating arm far away from the central axis is provided with an outer conical surface matched with the inner conical hole on the push-pull sleeve, and the clamping block is positioned on the inner side part of the rotating arm close to the central axis; and the rotating arm is connected with a spring for automatically opening the L-shaped clamping jaw.
6. The pipe bending process according to claim 1, wherein in the dynamic correction of the initial position of the hole site of the flange after the flanged pipe is clamped in the step S2, the positions of the plurality of holes on the flange are identified by the visual identification device disposed on the CNC pipe bending machine, and the correction of the initial bending angle position is performed according to the hole site errors of the plurality of holes on the identified flange.
7. The pipe bending process according to claim 2, wherein the dynamic correction of the initial position of the flange hole site after the flanged pipe is clamped in step S2 sequentially comprises the following steps:
(1) identifying a single hole of the flange: setting a camera coordinate system, and setting and identifying one of the single holes A and the positions on the pipe flange of the flanged pipeline through a visual identification device;
(2) the rotation center position is set: the trolley rotating mechanism rotates to drive a 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, coordinates of the single hole A at different positions are obtained through detection of a vision identification device, the position of a rotating center is calculated according to the coordinates of the single hole A at the different positions, and then an X-Y coordinate system with the rotating center as an origin is established;
(3) calculating the correction value of the hole position angle: taking the single hole A and another single hole B which is arranged on the pipe flange and forms an angle of 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 rotates 180 degrees, the single hole B is rotated to a corresponding position, the position of the single hole B in the X-Y coordinate system after the single hole B rotates is set by the vision setting device, and the included angle beta between the single hole B and the Y axis is calculated; taking the average value of alpha and beta, namely (alpha + beta)/2 as the hole site angle correction quantity;
(4) hole site correction: the trolley rotating mechanism rotates in the reverse direction for 180 degrees, so that the original single hole B rotating for 180 degrees is reset, and then the trolley rotating mechanism rotates to enable the single hole A to be positioned at a position which has an included angle (alpha + beta)/2 with the Y axis and is used as a correction position of the single hole A;
(5) setting a bending initial angle: and the trolley rotating mechanism of the pipe bender rotates to rotate the position of the single hole A to the initial angle set by the program, and then the pipe is bent automatically according to the bending program of the pipe bender.
8. The pipe bending process according to claim 7, wherein the rotation center of step (2) is determined by rotating the single hole a on the pipe flange to seven different positions, and calculating the rotation center position according to the coordinates of the single hole a at the seven different positions.
9. The pipe bending process for bending the flanged pipe by using the numerical control pipe bending machine according to claim 8, wherein a bending test is performed in advance before the flanged pipe is bent in batch, 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 introduced into three-dimensional design software and is compared with a three-dimensional design theoretical model of the flanged pipe to obtain an actual bending error of each bending part on the flanged pipe, and the actual bending error is written into a bending program as a compensation amount to form the bending program with the bending error compensation; and when the flanged pipeline is formally bent, the bending procedure with the bending error compensation is used for bending.
10. The pipe bending process according to claim 9, wherein when the flanged pipe has a plurality of bending nodes, the three-dimensional design software compares the bending nodes to obtain the bending error of the bending node.
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| CN116861569A (en) * | 2023-08-25 | 2023-10-10 | 北京星河动力装备科技有限公司 | Rocket engine pipeline assembly and manufacturing method thereof |
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