A cold bending forming device for special-shaped steel pipes

Abstract

The present invention relates to the technical field of steel pipe bending equipment, and particularly relates to a cold bending forming equipment for special-shaped steel pipes, which includes a workbench, a bending mechanism, and a plurality of holding mechanisms. The bending mechanism includes a pipe bending die and a clamping block, and the holding mechanism includes a holding frame and four clamping members. The holding frame is installed on the pipe bending die, and the four clamping members are all installed on the holding frame. A bending column is arranged on the pipe bending die, and the bending column is coaxially arranged with the pipe bending die. The cold bending forming equipment for special-shaped steel pipes of the present invention is provided with a bending mechanism and a holding mechanism on the workbench. After bending is completed, a plurality of holding mechanisms will all be located on the bending section, making it not easy for the side surface of the square pipe on the side close to the pipe bending die along the second direction to generate wrinkles towards the side close to the central axis of the square pipe, making it not easy for the side surface of the square pipe on the side close to the clamping block along the second direction to become flattened, reducing the influence on the inner diameter of the square pipe after bending, and improving the bending quality of the square pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of steel pipe bending equipment, and particularly relates to a cold bending forming equipment for special-shaped steel pipes. Background Art

[0002] Special-shaped steel pipes refer to steel pipes with non-circular cross-sections, such as square pipes, etc. Special-shaped steel pipes are widely used in various structural parts, tools, and mechanical components. Compared with round pipes, special-shaped steel pipes generally have larger moment of inertia and section modulus, and have greater bending and torsion resistance, which can greatly reduce the structural weight and save steel.

[0003] The extrusion method, the inclined die rolling method, and the cold bending forming method are all effective methods for producing special-shaped steel pipes. Among them, when cold bending a square steel pipe, defects are likely to occur during the bending process. The specific manifestations of the defects are: wrinkles on the inner side of the steel pipe, flattening of the outer side, resulting in a change in the inner diameter of the bent steel pipe. The existence of bending defects will have a great negative impact on the quality of the bent pipe fittings. On the one hand, it may cause a reduction in the cross-sectional area, thereby increasing the resistance of fluid flow. On the other hand, it also affects the function of the pipe fittings in the structure and the normal use of the bent pipe fittings. Summary of the Invention

[0004] The present invention provides a cold bending forming equipment for special-shaped steel pipes to solve the problem that in the existing steel pipe cold bending forming equipment, when bending a square pipe, wrinkles are likely to appear on the inner side of the steel pipe and the outer side becomes flattened, thereby affecting the normal use of the bent pipe fittings.

[0005] The cold bending forming equipment for special-shaped steel pipes of the present invention adopts the following technical solutions: A cold bending forming equipment for special-shaped steel pipes, used for bending square pipes, includes a workbench, a bending mechanism, and multiple holding mechanisms; The bending mechanism includes a pipe bending die and a clamping block. The pipe bending die is rotatably installed on the workbench around a first direction, and the first direction is the vertical direction; The clamping block is installed on the pipe bending die, and the clamping block can move along a second direction towards the side close to the pipe bending die to close the die with the pipe bending die. The second direction is perpendicular to the first direction, and the second direction is the horizontal direction; The clamping space for clamping the square pipe is defined between the clamping block and the pipe bending die after closing the die. In the initial state, the square pipe is arranged along a third direction, and multiple holding mechanisms are arranged in sequence along the third direction on the pipe bending die. The third direction is perpendicular to the first direction and the second direction respectively, and the third direction is the horizontal direction. The holding mechanism includes a holding frame and four clamping members. The holding frame is installed on the pipe bending die, and the four clamping members are all installed on the holding frame. The four clamping members are respectively located in the four right-angle areas of the square pipe. Each clamping member can apply a force towards the side of the central axis of the square pipe to its corresponding right-angle area, and make the four side surfaces of the square pipe in the right-angle area in the third direction all become arc surfaces, and the concave side of the arc surface is arranged towards the central axis of the square pipe; A bending column is arranged on the pipe bending die, and the bending column is coaxially arranged with the pipe bending die. The part of the square pipe to be bent is called the bending section. The bending column can drive multiple holding frames to rotate around the first direction, and make multiple holding frames evenly distributed along the axis direction of the bending section on the bending section.

[0006] Further, the bending column has a head end and a tail end, and the head end and the tail end are arranged in sequence in the rotation direction of the pipe bending die. In the rotation direction of the pipe bending die, the head end is located in front of the tail end; And from the head end to the tail end, the diameter of the bending column gradually increases; Multiple holding frames are all slidably installed on the pipe bending die. A fitting groove is provided on each holding frame, and the fitting groove is slidably fitted with the bending column. In the initial state, multiple holding frames are all slidably installed on the side of the head end of the bending column. The sizes of multiple fitting grooves are different, and the size of the fitting groove close to the head end of the bending column is smaller than the size of the fitting groove close to the tail end of the bending column. Furthermore, during the rotation of the bending column with the pipe bending die, when the diameter of the bending column can be adapted to the diameter of the fitting groove, the holding frame where the fitting groove is located can rotate synchronously with the bending column around the first direction.

[0007] Further, two adjacent holding frames are connected by a first elastic member.

[0008] Further, the holding frame includes a first frame body and a second frame body. The first frame body is slidably installed on the pipe bending die. The second frame body is connected to the first frame body, and the second frame body can move along the second direction towards the side close to or away from the first frame body. Two clamping members are respectively arranged on the first frame body and the second frame body, and the two clamping members on the first frame body and the two clamping members on the second frame body are arranged face to face in the second direction.

[0009] Further, the clamping member is a clamping wheel, and the clamping wheel is rotatably arranged around a reference axis, where the reference axis is the tangent direction of the right-angle region of the square tube where the clamping wheel is located; and the two clamping wheels on the first frame body can approach each other in the first direction, and the two clamping wheels on the second frame body can approach each other in the first direction.

[0010] Further, it further includes a limiting mechanism, and the limiting mechanism includes a driving block. The driving block can move closer to or away from the side of the square tube in the second direction, and when the driving block moves closer to the side of the square tube in the second direction, it can abut against the square tube.

[0011] Further, the limiting mechanism further includes a limiting block. The limiting block is installed on the driving block and can move synchronously with the driving block. A clamping groove is provided on the limiting block. When the limiting block moves closer to the side of the square tube in the second direction, the clamping groove can be in sliding fit with the square tube, and the limiting block can move relative to the driving block in the third direction.

[0012] Further, a limiting groove is provided on the bending die, and the bent square tube can abut in the limiting groove.

[0013] Further, three holding mechanisms are provided.

[0014] Further, a sliding groove is provided on the bending die, and the sliding groove is coaxially arranged with the bending die. A plurality of holding frames are all slidably installed in the sliding groove.

[0015] The beneficial effects of the present invention are as follows: A cold bending forming device for special-shaped steel pipes of the present invention is provided with a bending mechanism and a holding mechanism on the workbench. During bending, the rotation of the bending die will drive the clamping block and the square tube in the clamping space to rotate, and the square tube is bent. And during the rotation of the bending die, the bending column thereon will be driven to rotate. The bending column can drive the corresponding holding frame to rotate around the first direction. After bending, a plurality of holding frames will be evenly distributed along the axial direction of the square tube on the bending section, that is, a plurality of holding mechanisms will be on the bending section. And since the side surface (the inner side surface of the square tube) of the square tube close to the bending die in the second direction and the side surface (the outer side surface of the square tube) of the square tube close to the clamping block in the second direction are both arc surfaces, when the inner side surface of the square tube is bent, the arc-shaped inner side surface can guide the bending force, making it not easy for the inner side surface to produce wrinkles towards the side close to the central axis of the square tube. When the outer side surface of the square tube is bent, there is a certain margin on the outer side surface, and there is a certain buffering effect when the outer side surface is subjected to bending and stretching, making it not easy for the outer side surface to become flat, reducing the influence on the inner diameter of the square tube after bending, and improving the bending quality of the square tube. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0017] Figure 1 Schematic diagram of the overall structure of an embodiment of a cold bending forming device for special-shaped steel pipes of the present invention;

[0018] Figure 2 For Figure 1 Enlarged view of part A in

[0019] Figure 3 For Figure 1 Enlarged view of part B in

[0020] Figure 4 Top view of the overall structure of an embodiment of a cold bending forming device for special-shaped steel pipes of the present invention;

[0021] Figure 5 For Figure 4 Cross-sectional view along C-C in

[0022] Figure 6 For Figure 5 Enlarged view of part D in

[0023] Figure 7 Schematic diagram of the holding mechanism of an embodiment of a cold bending forming device for special-shaped steel pipes of the present invention;

[0024] Figure 8 Schematic diagrams of a square steel pipe before and after deformation in an embodiment of a cold bending forming device for special-shaped steel pipes of the present invention.

[0025] In the figure: 100, square steel pipe; 200, workbench; 210, first driving member; 220, support seat; 230, fourth driving member; 300, bending mechanism; 310, pipe bending die; 311, second driving member; 312, chute; 313, limiting groove; 320, clamping block; 330, bending column; 331, first end; 332, second end; 400, holding mechanism; 410, holding frame; 411, mating groove; 412, first frame body; 413, second frame body; 414, first inclined groove; 415, third driving member; 420, clamping wheel; 500, limiting mechanism; 510, driving block; 520, limiting block; 521, clamping groove; 530, fifth driving member. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] An embodiment of a cold bending forming device for special-shaped steel pipes of the present invention is as Figures 1 to 8 shown.

[0028] A cold bending forming device for special-shaped steel pipes is used to bend a square pipe 100, and includes a workbench 200, a bending mechanism 300, and a plurality of holding mechanisms 400. The bending mechanism 300 includes a pipe bending die 310 and a clamping block 320. The pipe bending die 310 is rotatably installed on the workbench 200 around a first direction, and the first direction is the vertical direction. The clamping block 320 is installed on the pipe bending die 310, and the clamping block 320 can move along a second direction toward the side close to the pipe bending die 310 to close the mold with the pipe bending die 310. The second direction is perpendicular to the first direction, and the second direction is the horizontal direction. A clamping space for clamping the square pipe 100 is defined between the clamping block 320 and the pipe bending die 310 after closing the mold. In the initial state, the square pipe 100 is arranged along a third direction, and a plurality of holding mechanisms 400 are sequentially arranged on the pipe bending die 310 along the third direction. The third direction is perpendicular to the first direction and the second direction respectively, and the third direction is the horizontal direction.

[0029] The holding mechanism 400 includes a holding frame 410 and four clamping members. The holding frame 410 is installed on the pipe bending die 310, and the four clamping members are all installed on the holding frame 410. The four clamping members are respectively located in the four right-angle regions of the square pipe 100. Each clamping member can apply a force toward the center axis side of the square pipe 100 to the corresponding right-angle region, and make the four side surfaces of the square pipe 100 in the right-angle region in the third direction all become arc surfaces, and the concave side of the arc surface is arranged toward the center axis of the square pipe 100. A bending column 330 is arranged on the pipe bending die 310, and the bending column 330 is coaxially arranged with the pipe bending die 310. The part of the square pipe 100 to be bent is called a bending section. The bending column 330 can drive a plurality of holding frames 410 to rotate around the first direction, and make the plurality of holding frames 410 evenly distributed along the axis direction of the bending section on the bending section.

[0030] Specifically, a first driving member 210 is arranged on the workbench 200, and the first driving member 210 is used to drive the pipe bending die 310 to rotate around the first direction. The first driving member 210 is a motor. A second driving member 311 is arranged on the pipe bending die 310, and the second driving member 311 can drive the clamping block 320 to move along the second direction toward the side close to or away from the pipe bending die 310. The second driving member 311 is a hydraulic telescopic cylinder.

[0031] Furthermore, there are three holding mechanisms 400 provided. Alternatively, the number of holding mechanisms 400 is set to more than three. A support base 220 is provided on the workbench 200. The support base 220 is coaxially arranged with the clamping space. The square tube 100 is placed on the support base 220 and can move along the support base 220.

[0032] In this embodiment, by providing the bending mechanism 300 and the holding mechanism 400 on the workbench 200, during use, first, the square tube 100 is clamped in the clamping space, and then the clamping block 320 is driven to move along the second direction towards the side close to the bending die 310 to close the mold with the bending die 310, and the clamping member applies a force towards the central axis side of the square tube 100 to the right-angle area of the corresponding square tube 100, so that the four side surfaces of the square tube 100 in the right-angle area in the third direction (the length direction of the square tube 100) are respectively deformed towards the side away from the central axis of the square tube 100. Refer to the attached Figure 8 As shown, the square tube 100 before deformation is represented by Figure 8 the dotted line in Figure 8 and the square tube 100 after deformation is represented by

[0033] the solid line in. That is, the four side surfaces of the square tube 100 all bulge towards the side away from the central axis of the square tube 100 and are arc-shaped.

[0034] In this embodiment, the bending column 330 has a first end 331 and a second end 332. The first end 331 and the second end 332 are arranged in sequence in the rotation direction of the pipe bending die 310. In the rotation direction of the pipe bending die 310, the first end 331 is located on the front side of the second end 332. That is, the pipe bending die 310 rotates clockwise in the direction shown in the attached Figure 4 figure. The direction close to the arrow side of the clockwise rotation in the rotation direction is called the front, and the direction far from the arrow side of the clockwise rotation is called the back. And from the first end 331 to the second end 332, the diameter of the bending column 330 gradually increases. A plurality of cages 410 are all slidably mounted on the pipe bending die 310. Each cage 410 is provided with a mating groove 411. The mating groove 411 is slidably mated with the bending column 330. In the initial state, a plurality of cages 410 are all slidably mounted on the side of the first end 331 of the bending column 330. The sizes of the plurality of mating grooves 411 are different. And the size of the mating groove 411 close to the first end 331 of the bending column 330 is smaller than the size of the mating groove 411 close to the second end 332 of the bending column 330. And the size of the mating groove 411 close to the second end 332 of the bending column 330 is smaller than the diameter of the second end 332 of the bending column 330. The size of the mating groove 411 close to the first end 331 of the bending column 330 is larger than the diameter of the first end 331 of the bending column 330. Furthermore, in the process of the bending column 330 rotating with the pipe bending die 310, when the diameter of the bending column 330 can be adapted to the diameter of the mating groove 411, the cage 410 where the mating groove 411 is located can rotate synchronously with the bending column 330 around the first direction.

[0035] Specifically, a chute 312 is provided on the pipe bending die 310. The chute 312 is coaxially arranged with the pipe bending die 310. A plurality of cages 410 are all slidably mounted in the chute 312.

[0036] In this embodiment, the bending post 330 is configured with a gradually changing diameter. When in use, when the pipe bending die 310 rotates, the bending post 330 will also rotate with the pipe bending die 310. Since initially, a plurality of mating grooves 411 are all slidably installed on one side of the first end 331 of the bending post 330, at this time, the bending post 330 and the mating grooves 411 are not adaptable. The bending post 330 will rotate around the first direction relative to the plurality of cages 410. At this time, the cages 410 will slide in the sliding grooves 312. As the pipe bending die 310 rotates, the diameter of the bending post 330 passing through the mating grooves 411 gradually increases. When it rotates to a position where the diameter of the mating groove 411 can be adapted to the diameter of the bending post 330, the cage 410 corresponding to the mating groove 411 can be driven to rotate by the bending post 330. Since the diameter of the bending post 330 gradually increases from the first end 331 to the second end 332, as the bending post 330 rotates relative to the mating grooves 411, whenever the diameter of the bending post 330 can be adapted to the diameter of a mating groove 411, the bending post 330 will be able to drive the cage 410 where the mating groove 411 it is adapted to is located to rotate. That is, when in use, the bending angle of the square pipe 100 is known. By setting the central angle on the pipe bending die 310 of the diameter of the bending post 330 that can be adapted to the mating groove 411, a plurality of cages 410 can be evenly distributed on the bent section of the bent square pipe 100. For example, when the bending angle of the square pipe 100 is 120° and the number of cages 410 is set to 3, then the included angles between the three cages 410 arranged in sequence on the bent section of the square pipe 100 are all 40 degrees.

[0037] In this embodiment, a limiting groove 313 is formed on the pipe bending die 310, and the bent square pipe 100 can abut against the limiting groove 313.

[0038] By setting the limiting groove 313, the inner side surface of the bent square pipe 100 will abut against the limiting groove 313. This setting is because after the square pipe 100 is bent, under the action of the arc surface on the inner side surface of the square pipe 100, the inner side surface of the square pipe 100 will tend to move towards the side close to the limiting groove 313. By using the limiting groove 313 to limit the inner side surface of the bent square pipe 100, the amount of movement of the inner side surface of the square pipe 100 towards the side close to the limiting groove 313 is restricted.

[0039] In this embodiment, two adjacent cages 410 are connected by a first elastic member, and the first elastic member is a spring. By arranging the first elastic member between two adjacent cages 410, it is convenient for the cages 410 to reset.

[0040] In this embodiment, the cage 410 includes a first frame body 412 and a second frame body 413. The first frame body 412 is slidably mounted on the bent pipe die 310. The second frame body 413 is connected to the first frame body 412 through a third driving member 415, so that the second frame body 413 can move along a second direction towards or away from one side of the first frame body 412. And when the second frame body 413 moves along the second direction towards one side of the first frame body 412, the second frame body 413 and the first frame body 412 can clamp the square pipe 100. The third driving member 415 is a hydraulic telescopic cylinder. Two clamping members are respectively arranged on the first frame body 412 and the second frame body 413, and the two clamping members on the first frame body 412 and the two clamping members on the second frame body 413 are arranged face to face in the second direction.

[0041] In this embodiment, the clamping member is a clamping wheel 420. The clamping wheel 420 is rotatably arranged about a reference axis, and the reference axis is the tangent direction of the right-angle area of the square pipe 100 where the clamping wheel 420 is located. And the two clamping wheels 420 on the first frame body 412 can approach each other along a first direction, and the two clamping wheels 420 on the second frame body 413 can approach each other along the first direction.

[0042] Specifically, two first inclined grooves 414 are formed on the first frame body 412. The two first inclined grooves 414 are symmetrically arranged about the central axis of the square pipe 100 in the first direction. The two first inclined grooves 414 are arranged in one-to-one correspondence with the two clamping wheels 420 correspondingly arranged on the first frame body 412. The clamping wheels 420 on the first frame body 412 are slidably mounted in the corresponding first inclined grooves 414. The two ends of the first inclined groove 414 are respectively called a first end and a second end. The first end is located on the side of the second end close to the square pipe 100 in the second direction, and the first end is located on the side of the second end far from the central axis of the square pipe 100 in the first direction in the first direction. In the initial state, the clamping wheels 420 on the first frame body 412 are located on the side of the first end of the first inclined groove 414.

[0043] Two second inclined grooves are formed on the second frame body 413. The two second inclined grooves are symmetrically arranged about the central axis of the square pipe 100 in the first direction. The two second inclined grooves are arranged in one-to-one correspondence with the two clamping wheels 420 correspondingly arranged on the second frame body 413. The clamping wheels 420 on the second frame body 413 are slidably mounted in the corresponding second inclined grooves. The two ends of the second inclined groove are respectively called a third end and a fourth end. The third end is located on the side of the fourth end close to the square pipe 100 in the second direction, and the third end is located on the side of the fourth end far from the central axis of the square pipe 100 in the first direction in the first direction. In the initial state, the clamping wheels 420 on the second frame body 413 are located on the side of the third end of the second inclined groove.

[0044] In this embodiment, by providing a first frame body 412 and a second frame body 413, during use, the third driving member 415 is used to urge the second frame body 413 to move along the second direction towards the first frame body 412, so as to clamp the square tube 100. And during the movement of the first driving member 210, the two clamping wheels 420 on the first frame body 412 and the two clamping wheels 420 on the second frame body 413 will gradually apply a force towards the central axis of the square tube 100 to the four right-angle regions of the square tube 100 where they are located. And during the process of the first frame body 412 and the second frame body 413 approaching each other in the second direction, driven by the third driving member 415, the two clamping wheels 420 on the first frame body 412 will tend to approach each other in the first direction. Similarly, the two clamping wheels 420 on the second frame body 413 will also tend to approach each other in the first direction. As a result, the forces applied by the four clamping wheels 420 to the square tube 100 all tend to the central axis side of the square tube 100. Under the action of the four clamping wheels 420, the four side surfaces of the square tube 100 in contact with and pressed by the clamping wheels 420 will gradually become arc surfaces, and the concave side of the arc surface is arranged towards the central axis of the square tube. Refer to the attached Figure 8 As shown, the square tube 100 before deformation is represented by Figure 8 the dashed line in the figure, and the square tube 100 after deformation is represented by Figure 8 the solid line in the figure. That is, the four side surfaces of the square tube 100 bulge towards the side away from the central axis of the square tube 100 and are arc-shaped.

[0045] In this embodiment, a cold bending forming device for a special-shaped steel pipe further includes a limiting mechanism 500. The limiting mechanism 500 includes a driving block 510. The driving block 510 and the clamping block 320 are on the same side of the workbench 200. A fourth driving member 230 is provided on the workbench 200. The driving block 510 is installed on the fourth driving member 230. The fourth driving member 230 can urge the driving block 510 to move along the second direction towards or away from the square tube 100, and when the driving block 510 moves along the second direction towards the square tube 100, it can abut against the square tube 100.

[0046] Furthermore, the limiting mechanism 500 further includes a limiting block 520. The limiting block 520 is installed on the driving block 510 and can move synchronously with the driving block 510. A clamping groove 521 is provided on the limiting block 520. When the limiting block 520 moves along the second direction towards the square tube 100, the clamping groove 521 can be in sliding fit with the square tube 100. A fifth driving member 530 is provided on the driving block 510. The fifth driving member 530 can enable the limiting block 520 to move relative to the driving block 510 along the third direction. Both the fourth driving member 230 and the fifth driving member 530 are hydraulic telescopic cylinders.

[0047] In this embodiment, by providing a driving block 510 and a limiting block 520, during use, the fourth driving member 230 is utilized to urge the driving block 510 to move along the second direction towards the side closer to the square tube 100. The movement of the driving block 510 will drive the limiting block 520 to move until the limiting groove 313 abuts against the square tube 100. When bending the square tube 100, the fifth driving member 530 is activated to drive the limiting block 520 to move synchronously with the square tube 100, so that the square tube 100 and the limiting block 520 remain relatively stationary, preventing the square tube 100 from being scratched.

[0048] In another possible embodiment, a cold bending forming device for a special-shaped steel tube further includes a control system. A first sensor is provided on the first frame body 412, and the first sensor is used to sense the dimension of the inner side surface of the square tube 100 in the first direction. A second sensor is provided on the second frame body 413, and the second sensor is used to sense the dimension of the outer side surface of the square tube 100 in the first direction. Both the first sensor and the second sensor are position sensors. Both the first sensor and the second sensor are electrically connected to the control system, and the control system can collect the information fed back by the first sensor and the second sensor. The first driving member 210, the second driving member 311, the third driving member 415, the fourth driving member 230, and the fifth driving member 530 are all electrically connected to the control system. The control system can control the first driving member 210, the second driving member 311, the third driving member 415, the fourth driving member 230, and the fifth driving member 530 to start or stop.

[0049] By providing the first sensor and the second sensor, during use, the dimension of the inner side surface of the square tube 100 in the first direction and the dimension of the outer side surface of the square tube 100 in the first direction can be sensed, and the data obtained through the feedback of the control system can be analyzed. If the square tube 100 becomes flattened, the dimension of the inner side surface of the square tube 100 in the first direction and the dimension of the outer side surface of the square tube 100 in the first direction will both change. Therefore, after collecting the data, adjustments can be made to change the relative displacement amount between the first frame body 412 and the second frame body 413, thereby improving the bending quality of the square tube 100.

[0050] Combining the above embodiments, the working process is as follows:

[0051] During use, first place the square tube 100 on the workbench 200, lap it on the support base 220 and pass through the clamping space. Then start the second driving member 311, the third driving member 415 and the fourth driving member 230. Starting the second driving member 311 will cause the clamping block 320 to move along the second direction towards or away from the side of the bending die 310 and clamp the square tube 100. Starting the third driving member 415 will cause the second frame body 413 to move along the second direction towards the side of the first frame body 412 and clamp the square tube 100. Starting the fourth driving member 230 will cause the driving block 510 to move along the second direction towards the side of the square tube 100. The movement of the driving block 510 will drive the limiting block 520 to move until the limiting groove 313 abuts against the square tube 100.

[0052] And when the second frame body 413 is urged to move along the second direction towards the side of the first frame body 412 by the third driving member 415, the square tube 100 can be clamped. And during the movement of the first driving member 210, the two clamping wheels 420 on the first frame body 412 and the two clamping wheels 420 on the second frame body 413 will gradually apply a force towards the central axis side of the square tube 100 to the four right-angle regions of the square tube 100 where they are located. And during the process of the first frame body 412 and the second frame body 413 approaching each other in the second direction, under the drive of the third driving member 415, the two clamping wheels 420 on the first frame body 412 will have a tendency to approach each other in the first direction. Similarly, the two clamping wheels 420 on the second frame body 413 will also have a tendency to approach each other in the first direction. As a result, the forces applied by the four clamping wheels 420 to the square tube 100 all tend towards the central axis side of the square tube 100. Under the action of the four clamping wheels 420, the four side surfaces of the square tube 100 in contact with and pressed by the clamping wheels 420 will gradually become arc surfaces, and the concave side of the arc surface is arranged towards the central axis of the direction. See the attached Figure 8 As shown, the square tube 100 before deformation is represented by Figure 8 the dashed line in Figure 8 and the square tube 100 after deformation is represented by

[0053] the solid line in

[0054] That is, the four side surfaces of the square tube 100 bulge towards the side away from the central axis of the square tube 100 and are arc-shaped.

[0053] Then start the first driving member 210 to drive the bending die 310 to rotate around the first direction. The rotation of the bending die 310 will drive the clamping block 320 and the square tube 100 in the clamping space to rotate, and bend the square tube 100. When bending the square tube 100, start the fifth driving member 530 to drive the limiting block 520 to move synchronously with the square tube 100, so that the square tube 100 and the limiting block 520 remain relatively stationary to prevent the square tube 100 from being scratched.

[0054] And when the elbow die 310 rotates, the bending column 330 will also rotate with the elbow die 310. Since in the initial state, multiple engaging grooves 411 are all slidably mounted on one side of the head end 331 of the bending column 330, at this time, the bending column 330 and the engaging grooves 411 are not adapted, and the bending column 330 will rotate around the first direction relative to the plurality of cages 410. At this time, the cages 410 will slide in the sliding grooves 312. As the elbow die 310 rotates, the diameter of the bending column 330 passing through the engaging grooves 411 gradually increases. When it rotates to a position where the diameter of the engaging groove 411 can be adapted to the diameter of the bending column 330, the cage 410 corresponding to the engaging groove 411 can be driven to rotate by the bending column 330.

[0055] Since the diameter of the bending column 330 gradually increases from the head end 331 to the tail end 332, therefore, as the bending column 330 rotates relative to the engaging groove 411, whenever the diameter of the bending column 330 can be adapted to the diameter of an engaging groove 411, the bending column 330 will be able to drive the cage 410 where the engaging groove 411 adapted to it is located to rotate. That is, in use, the bending angle of the square tube 100 is known. By setting the central angle on the elbow die 310 of the diameter of the bending column 330 that can be adapted to the engaging groove 411, the plurality of cages 410 can be evenly distributed on the bending section of the bent square tube 100. That is, the plurality of holding mechanisms 400 will all be in the bending section. And since the inner side surface of the square tube 100 is an arc surface, when the inner side surface of the square tube 100 is bent, the arc-shaped inner side surface can play a guiding role in the bending force, making it not easy for the inner side surface to produce wrinkles towards the side close to the central axis of the square tube 100. When the outer side surface of the square tube 100 is bent, there is a certain margin on the outer side surface, which has a certain buffering effect when the outer side surface is subjected to bending and stretching, making it not easy for the outer side surface to become flat, reducing the influence on the inner diameter of the square tube 100 after bending, and improving the bending quality of the square tube 100.

[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cold bending forming equipment for special-shaped steel pipes, used for bending square pipes, characterized by: It includes a workbench, a bending mechanism and multiple holding mechanisms; the bending mechanism includes a tube bending die and a clamping block, the tube bending die can be installed on the workbench so as to rotate around a first direction, the first direction is a vertical direction; the clamping block is installed on the tube bending die, the clamping block can move along a second direction to a side close to the tube bending die to close the tube bending die with the tube bending die, the second direction is perpendicular to the first direction, and the second direction is a horizontal direction; a clamping space for clamping a square tube is defined between the clamping block and the tube bending die after closing the mold, in an initial state, the lower tube is arranged along a third direction and multiple holding mechanisms are arranged in sequence on the tube bending die along the third direction, the third direction is perpendicular to the first direction and the second direction respectively, the third direction is a horizontal direction, and the holding mechanism includes a holding mechanism. A holder and four clamping members, the holder is installed on the tube bending die, and the four clamping members are all installed on the holder, and the four clamping members are respectively located in four right-angle areas of the square tube, and each clamping member can apply a force toward one side of the central axis of the square tube to the right-angle area corresponding to it, and make the four side surfaces of the square tube in the right-angle area in the third direction become arc surfaces, and the concave side of the arc surface is arranged toward the central axis of the square tube; a bending column is arranged on the tube bending die, and the bending column is coaxially arranged with the tube bending die, and the bent part of the square tube is called a bending section, and the bending column can drive multiple holders to rotate around the first direction, and make the multiple holders evenly distributed on the bending section along the axial direction of the bending section.

2. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: The bending column has a head end and a tail end, which are arranged in sequence in the rotation direction of the bending die. In the rotation direction of the bending die, the head end is located in front of the tail end; and the diameter of the bending column gradually increases from the head end to the tail end; multiple retaining frames are slidably installed on the bending die, and each retaining frame is provided with a matching groove, which is slidably matched with the bending column. In the initial state, multiple retaining frames are slidably installed on the head end side of the bending column, and the sizes of the multiple matching grooves are different, and the size of the matching groove close to the head end of the bending column is smaller than the size of the matching groove close to the tail end of the bending column. Therefore, in the process of the bending column rotating with the bending die, when the diameter of the bending column can adapt to the diameter of the matching groove, the retaining frame where the matching groove is located can rotate synchronously with the bending column around the first direction.

3. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: Two adjacent retaining frames are connected via a first elastic member.

4. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: The retaining frame includes a first frame body and a second frame body. The first frame body is slidably installed on the tube bending mold. The second frame body is connected to the first frame body, and the second frame body can move toward or away from one side of the first frame body along the second direction. Two clamping members are respectively arranged on the first frame body and the second frame body, and the two clamping members on the first frame body and the two clamping members on the second frame body are arranged face to face in the second direction.

5. The cold-bending forming equipment for special-shaped steel pipes according to claim 4, characterized in that: The clamping member is a clamping wheel, which can be rotatably arranged around a reference axis, and the reference axis is the tangent direction of the right-angle area of ​​the square tube where the clamping wheel is located; and the two clamping wheels on the first frame can approach each other along the first direction, and the two clamping wheels on the second frame can approach each other along the first direction.

6. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: It also includes a limiting mechanism, which includes a driving block. The driving block can move toward or away from one side of the square tube along the second direction, and the driving block can abut against the square tube when it moves toward one side of the square tube along the second direction.

7. The cold-bending forming equipment for special-shaped steel pipes according to claim 6, characterized in that: The limiting mechanism also includes a limiting block, which is installed on the driving block and can move synchronously with the driving block. A slot is provided on the limiting block. When the limiting block moves along the second direction toward the side close to the square tube, the slot can slide with the square tube. The limiting block can move along the third direction relative to the driving block.

8. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: A limiting groove is provided on the tube bending die, and the bent square tube can abut against the limiting groove.

9. The cold-bending forming equipment for special-shaped steel pipes according to claim 1, characterized in that: There are three holding mechanisms.

10. The cold-bending forming equipment for special-shaped steel pipes according to claim 2, characterized in that: A slide groove is provided on the tube bending die, the slide groove is coaxially arranged with the tube bending die, and a plurality of retaining frames are slidably installed in the slide groove.

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