A method for forming a large-curvature and large-angle bent member

Abstract

The present invention discloses a method for forming a large-curvature and large-angle bending member, which is completed by using a device for forming a large-curvature and large-angle bending member, and includes the following steps: (1) generating an instruction code for pipe bending processing; (2) fitting the clamping cushion block with the clamping block to complete the clamping of the pipe blank; (3) performing the first winding; (4) performing the second winding. Starting from the second winding action, each subsequent winding action is the same as the first winding, except that the curved die cushion block 7 and the clamping cushion block 6 are not involved. (5) Next, repeat the above second winding action according to the actual bending angle of the member. After completion, finally, cut off the straight section at the front end of the bent member by using a cutting machine to obtain the final finished product.

Description

Technical Field

[0001] The present invention belongs to the technical field of machining, and particularly relates to a method for forming a large-curvature and large-angle bending member. Background Art

[0002] The numerical control bending technology is developed on the basis of the traditional pipe bending technology by combining the machine tool industry and numerical control technology. It is an efficient pipe bending processing technology with the advantages of high efficiency, high precision, and low forming force. It is considered a reliable forming technology for forming metal bending members with various pipes and profiles and occupies an important position in the modern pipe bending industry.

[0003] However, generally, when facing the continuous forming of large-curvature and large-bending-angle members, it is difficult to form using the existing bending technology. Since the die size of the conventional bending equipment is small, the formed bending member has a small curvature or a small bending angle of the member when meeting the large curvature, and it is difficult to meet both large curvature and large angle at the same time. If the method of segmental bending and then welding is adopted, there are many welds on the welded member, and the forming quality is poor, which cannot meet the higher usage requirements. If large-size dies are processed according to actual needs, the processing difficulty and cost of the dies are high, which does not meet the actual production requirements. Summary of the Invention

[0004] In view of the deficiencies of the existing technology and the characteristics of bending forming, the present invention provides a method for forming a large-curvature and large-angle bending member, which is applicable to the bending forming of thin-walled members with a large curvature radius and a large bending angle during the forming process.

[0005] The present invention is realized by the following technical solutions:

[0006] A method for forming a large-curvature and large-angle bending member is completed by using a device for forming a large-curvature and large-angle bending member. The device includes a bending die 1, a pipe pushing mechanism 3, a boosting block 4, a clamping block 5, a clamping cushion block 6, and a bending die cushion block 7; the bending die 1 is a thin plate with a sector structure. Taking the center line of the sector structure as the boundary, the front section of the sector structure is a clamping area, and the rear section is a forming area; the clamping block 5, the clamping cushion block 6, and the bending die cushion block 7 are located in the clamping area and cooperate with the bending die 1 to clamp the pipe blank 2. The radius R of the sector structure is equal to the curvature radius of the target bending member. The sector is provided with a first semi-circular groove along the circumference, and the radius of the first semi-circular groove is r, where r is the radius of the pipe blank; clamping cushion blocks 6 and bending die cushion blocks 7 are installed in the clamping area to stabilize the straight section at the front end of the pipe blank when forming the first bending section; the method includes the following steps:

[0007] (1) Perform three-dimensional modeling on the target bending member, import its three-dimensional model data into the numerical control pipe bending system, and generate the instruction code for pipe bending processing;

[0008] (2) Fix the bending die spacer block at the clamping area at the front end of the bending die. The clamping spacer block fits with the clamping block, and the pipe pushing mechanism pushes the pipe until its front end is in the same position as the front ends of the two spacer blocks.

[0009] (3) Conduct the first bending. After the bending die, the clamping block, and the boosting block horizontally move along the slide rail to clamp the pipe blank, the bending die and the clamping block rotate on the same rotating shaft. The angle θ of a single bending is half of the central angle of the bending die. During the bending process, the boosting block axially translates forward along with the pipe.

[0010] (4) After the first bending is completed, the bending die, the clamping block, and the boosting block move away from the pipe along the slide rail. The bending die and the clamping block return to the horizontal position by rotating around the rotating shaft. At the same time, remove the spacer blocks and no longer use them. Execute the second bending. Starting from the second bending operation, each subsequent bending operation is the same as the first bending, except that the bending die spacer block 7 and the clamping spacer block 6 are not involved.

[0011] (5) Next, repeat the above second bending operation according to the actual bending angle of the component. After completion, cut off the straight section at the front end of the bent component using a cutting machine to obtain the final finished product.

[0012] In the method described above, the bending angle range of the bent component can reach 0 - 360°.

[0013] In the method described above, the curvature radius of the formed component is more than 1 m.

[0014] In the method described above, each bending section is continuous and there is no straight section in the middle, forming a continuous large formed angle component.

[0015] In the method described above, the advancing distance of the pipe during a single complete bending process is

[0016] If the bending angle of the component is α, and α cannot be divided evenly by θ, then let the bending angle of the last section be: The remainder β, then the advancing distance of the pipe in the last section is

[0017] In the formula: R is the bending radius of the component, with the unit of mm; θ is half of the central angle size of the bending die, with the unit of “°”; α is the bending angle of the component, with the unit of “°”; β is The remainder, with the unit of “°”.

[0018] In the method described above, the central angle of the sector is selected within the range of 60° - 90°.

[0019] In the described method, on one side of the clamping block 5 that cooperates with the bending die 1, there is a second semi-circular groove with the same curvature radius R and the same radius r as the bending die 1. The central angle of the second semi-circular groove is θ, and θ is half of the central angle of the bending die 1, ensuring that the clamping block 5 and the bending die 1 can fit together completely. The radius of the second semi-circular groove of the clamping block 5 is r, and r is the radius of the tube blank. The clamping block 5 and the bending die 1 can jointly clamp the tube blank 2 and rotate simultaneously along the same rotation axis, ensuring that the tube blank 2 bends smoothly in the forming area.

[0020] In the described method, on one side of the boosting block 4, there is a third semi-circular groove, which is arranged on the side facing the tube blank 2. The radius of the third semi-circular groove is r. The boosting block 4 feeds axially while the bending die 1 rotates, ensuring that the tube 2 bends stably in the forming area under the action of the bending die.

[0021] In the described method, the bending die spacer 7 is assembled between the first semi-circular groove of the bending die 1 and the clamping spacer 6 and is detachably fixed to the bending die 1. One side of the bending die spacer 7 that cooperates with the first semi-circular groove is composed of a semi-circular protrusion with a radius r. One side of the bending die spacer 7 that cooperates with the clamping spacer 6 is a fourth semi-circular groove with a radius r. Correspondingly, on one side of the clamping spacer 6 that cooperates with the bending die spacer 7, there is a fifth semi-circular groove. The space formed by the fourth semi-circular groove and the fifth semi-circular groove with the same diameter as the tube blank can clamp the tube blank. The other side of the clamping spacer 6 is set as an arc surface with the same curvature as the second semi-circular groove; it is attached to and detachably fixed to the second semi-circular groove of the clamping block 5 through this arc surface.

[0022] In the described method, S = S’, S1 = S1’, S2 = S2’. S is the maximum distance from the tangent of the center point of the bending die 1 to the bending die 1. S’ is the horizontal width at the front end of the bending die spacer 7. S1 is the difference in the horizontal widths between the front end and the rear end of the clamping block 5. S2 is the axial length of the clamping block 5. S1’ is the horizontal width at the rear end of the clamping spacer 6. S2’ is the axial length of the clamping spacer 6.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) It realizes the forming of large-radius and large-angle bending components by using small-sized rotary bending dies, greatly saving the manufacturing cost of the forming dies and the structures matching therewith.

[0025] (2) It realizes the forming of continuous large-curvature and large-angle bending components by using rotary bending technology. Compared with the traditional forming method of segmental bending and then welding, the integrated continuous forming process method significantly improves the forming quality of the components and meets higher service requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the bending die;

[0027] Figure 2 It is a schematic diagram of the clamping block;

[0028] Figure 3 It is a schematic diagram of the boosting block;

[0029] Figure 4 It is a schematic diagram of the bending die cushion block;

[0030] Figure 5 It is a schematic diagram of the clamping cushion block;

[0031] Figure 6 It is a schematic diagram at the start of the first-stage bending;

[0032] Figure 7 It is a schematic diagram at the end of the first-stage bending;

[0033] Figure 8 It is a schematic diagram at the start of the second-stage bending;

[0034] Figure 9 It is a schematic diagram of the bent component after final forming.

[0035] In the figure: 1. Bending die, 2. Tube blank, 3. Tube pushing mechanism, 4. Boosting block, 5. Clamping block, 6. Clamping cushion block, 7. Bending die cushion block; Specific implementation mode

[0036] The present invention will be described in detail below in combination with specific embodiments.

[0037] Reference Figures 1 - 5 , a device for forming a bent component with a large curvature and a large angle, comprising a bending die 1, a tube pushing mechanism 3, a boosting block 4, a clamping block 5, a clamping cushion block 6, and a bending die cushion block 7; the bending die 1 is a thin plate with a fan-shaped structure. Taking the center line of the fan-shaped structure as the boundary, the front section of the fan-shaped structure is the clamping area, and the rear section (the rear section is the side close to the tube pushing mechanism 3) is the forming area; the clamping block 5, the clamping cushion block 6, and the bending die cushion block 7 are located in the clamping area and cooperate with the bending die 1 to clamp the tube blank 2. The radius R of the fan-shaped structure is equal to the curvature radius of the target bent component. The central angle of the fan is generally selected within the range of 60° - 90°, which saves materials and is convenient for the movement of the mechanism. The fan is provided with a first semi-circular groove along the circumference, and the radius of the first semi-circular groove is r, and r is the radius of the tube blank. The clamping cushion block 6 and the bending die cushion block 7 are installed in the clamping area to stabilize the straight section at the front end of the tube blank during the forming of the first bending section, so as to smoothly form the first bending section. Therefore, there must be a straight section left at the front end of the bent component after forming;

[0038] On one side of the clamping block 5 that cooperates with the bending die 1, there is a second semi-circular groove with the same curvature radius R and the same radius r as the bending die 1. The central angle of the second semi-circular groove is θ, and θ is half of the central angle of the bending die 1. In this way, the clamping block 5 and the bending die 1 can fit together completely. The radius of the second semi-circular groove of the clamping block 5 is r, and r is the radius of the tube blank, which is convenient for better clamping of the tube blank 2. The clamping block 5 and the bending die 1 can jointly clamp the tube blank 2 and rotate simultaneously along the same rotation axis to ensure the stable bending of the tube blank 2 in the forming area.

[0039] On one side of the boosting block 4, there is a third semi-circular groove, which is arranged on the side facing the tube blank 2. The radius of the third semi-circular groove is r. The boosting block 4 feeds axially while the bending die 1 rotates to ensure the stable bending of the tube 2 in the forming area under the action of the bending die.

[0040] The bending die spacer block 7 is assembled between the first semi-circular groove of the bending die 1 and the clamping spacer block 6 and is detachably fixed to the bending die 1. One side of the bending die spacer block 7 that cooperates with the first semi-circular groove is composed of a semi-circular protrusion with a radius r. One side of the bending die spacer block 7 that cooperates with the clamping spacer block 6 is a fourth semi-circular groove with a radius r; correspondingly, one side of the clamping spacer block 6 that cooperates with the bending die spacer block 7 is provided with a fifth semi-circular groove. The space formed by the fourth semi-circular groove and the fifth semi-circular groove with the same diameter as the tube blank can clamp the tube blank; the other side of the clamping spacer block 6 is set as an arc surface with the same curvature as the second semi-circular groove; it is detachably fixed together by fitting this arc surface with the second semi-circular groove of the clamping block 5;

[0041] Reference Figures 1 - 5 , where the relevant parameters are S = S’, S1 = S1’, S2 = S2’. S is the farthest distance from the tangent line of the center point of the bending die 1 to the bending die 1, and S’ is the horizontal width of the front end of the bending die spacer block 7. S1 is the difference in the horizontal widths of the front end and the rear end of the clamping block 5, and S2 is the axial length of the clamping block 5. S1’ is the horizontal width of the rear end of the clamping spacer block 6, and S2’ is the axial length of the clamping spacer block 6. S = S’, S1 = S1’, S2 = S2’, which ensures that after the bending die spacer block 7 fits with the bending die 1 and the clamping spacer block 6 fits with the clamping block 5, the semi-circular grooves of the two just form a circular tubular space at the first bending to clamp the straight tube at the front end to stably form the subsequent bending section. After the first bending is completed, these two spacer blocks are removed and no longer used because the just-formed bending section can be exactly clamped by the bending die 1 and the clamping block 5 in the clamping area.

[0042] After the first bending is completed, each subsequent formed bending section is continuous and there is no straight section in the middle, forming a continuous large forming angle component. The curvature radius of the formed component can reach more than 1 m; the range of the bending angle of the bending component can reach 0 - 360°.

[0043] The bending angle of each bending section is half of the central angle of the bending die.

[0044] Example 1

[0045] A device and method for forming a large-curvature and large-angle bending member, including the following steps:

[0046] (1) Perform three-dimensional modeling on the target formed elbow member. The curvature radius of the member is 900 mm, and the bending angle is 195°. Import the three-dimensional model data of the target elbow member into the numerical control pipe bending system to generate the instruction code for pipe bending processing;

[0047] (2) Design a bending die 1 with a processing curvature radius of 900 mm and a central angle of 60° and its supporting mechanism;

[0048] (3) Fix the bending die spacer 7 at the clamping area at the front end of the bending die 1, fix the clamping spacer 6 on the clamping block 5, and the pipe pushing mechanism 3 pushes the pipe blank 2 to the front end positions of the bending die spacer 7 and the clamping spacer 6 to be consistent;

[0049] (4) As shown in Figure 7 , after the bending die 1, the clamping block 5 and the boosting block 4 horizontally move through the slide rail to press the pipe blank 2, the bending die 1 and the clamping block 5 rotate on the same rotating shaft, and the single bending angle θ is half of the central angle of the bending die 1, that is, 30°, and the boosting block 4 translates axially along with the pipe;

[0050] (5) As shown in Figure 8 , after the first bending is completed, the bending die 1, the clamping block 5, and the boosting block 4 move away from the pipe through the slide rail, and the bending die 1 and the clamping block 5 return to the horizontal position through the rotation of the rotating shaft. At the same time, remove the bending die spacer 7 and the clamping spacer 6 and no longer use them. Starting from the second bending action, each subsequent bending action is the same as the first bending, except that there is no participation of the bending die spacer 7 and the clamping spacer 6.

[0051] (6) During a single complete bending process in step (4), the advancing distance of the pipe is

[0052] The bending angle of the last section is: The remainder β of, then the advancing distance of the last section of the pipe is

[0053] In the formula: R is the bending radius of the member, in mm; θ is half of the central angle size of the bending die, in "°"; α is the total bending angle of the member, in "°"; β is The remainder of, in "°".

[0054] The bending angle α of the component is 195°, and the single complete bending angle is 30°. Then, the component needs to go through 6 bending processes of 30° and 1 bending process of 15°. According to the above formula, the component is composed of 6 complete bending segments with a length of 471.2 mm and 1 bending segment with a length of 235.6 mm;

[0055] (7) Next, complete 5 complete bends and 1 incomplete bend operation according to the actual bending angle of the component. After completion, cut off the starting straight segment with a cutting machine to obtain the final finished product. After measurement, the wall thickness reduction rate of the pipe fitting is about 12%, the cross-sectional change rate is about 5%, and there are no obvious defects such as wrinkles on the surface, and the forming quality is good.

[0056] Example 2

[0057] A device and method for forming a large-curvature and large-angle bending component, including the following steps:

[0058] (1) Perform three-dimensional modeling on the target bent pipe component to be formed. The curvature radius of the component is 1000 mm, and the bending angle is 225°. Import the three-dimensional model data of the target bent pipe component into the numerical control pipe bending system to generate the instruction code for pipe bending processing;

[0059] (2) Design a bending die 1 with a curvature radius of 1000 mm and a central angle of 60° and its supporting mechanism;

[0060] (3) Fix the bending die spacer 7 at the clamping area at the front end of the bending die 1, fix the clamping spacer 6 on the clamping block 5, and the pipe pushing mechanism 3 pushes the pipe blank 2 to the front end positions of the bending die spacer 7 and the clamping spacer 6 to be consistent;

[0061] (4) After the bending die 1, the clamping block 5 and the boosting block 4 horizontally move through the slide rail to press the pipe blank 2, the bending die 1 and the clamping block 5 rotate on the same rotation axis, and the single bending angle is half of the central angle of the bending die 1, that is, 30°, and the boosting block 4 translates along the axial direction of the pipe;

[0062] (5) As Figure 7 shown, after the first bending around in step (4) ends, the bending die 1, the clamping block 5, and the boosting block 4 move away from the pipe through the slide rail, the bending die 1 and the clamping block 5 return to the horizontal position through the rotation of the rotation axis, and at the same time, the bending die spacer 7 and the clamping spacer 6 are removed and no longer used.

[0063] (6) During a single complete bending process in step (4), the advancing distance of the pipe is

[0064] The bending angle of the component is 225°, then assume the bending angle of the last segment is The remainder β, then the advancement distance of the last section of pipe is

[0065] Where: R is the bending radius of the component, in mm; θ is half of the central angle of the bending die, in "°"; α is the total bending angle of the component, in "°"; β is The remainder, in "°".

[0066] According to the above formula, the component is composed of 7 complete bending sections with a length of 523.6 mm and 1 bending section with a length of 261.8 mm;

[0067] (7) Next, complete 6 complete bends and 1 incomplete bend according to the actual bending angle of the component. After completion, cut off the starting straight section with a cutting machine to obtain the final finished product. After measurement, the wall thickness reduction rate of the pipe fitting is about 13%, the cross-sectional change rate is about 4%, and there are no obvious defects such as wrinkles on the surface, and the forming quality is good.

[0068] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for forming a large-curvature and large-angle bent member, characterized in that, It is completed by a device for forming a large-curvature and large-angle bending member. The device includes a bending die (1), a pipe pushing mechanism (3), a boosting block (4), a clamping block (5), a clamping pad (6), and a bending die pad (7). The bending die (1) is a thin plate with a fan-shaped structure. Taking the center line of the fan-shaped structure as the boundary, the front section of the fan-shaped structure is the clamping area, and the rear section is the forming area. The clamping block (5), the clamping pad (6), and the bending die pad (7) are located in the clamping area and cooperate with the bending die (1) to clamp the pipe blank (2). The radius R of the fan-shaped structure is equal to the curvature radius of the target bending member. The fan is provided with a first semi-circular groove along the circumference, and the radius of the first semi-circular groove is r, where r is the radius of the pipe blank. The clamping pad (6) and the bending die pad (7) are installed in the clamping area to stabilize the straight section at the front end of the pipe blank when forming the first bending section. The method includes the following steps: (1) Perform three-dimensional modeling on the target bending member, import its three-dimensional model data into the numerical control pipe bending system, and generate the instruction code for pipe bending processing; (2) Fix the bending die pad at the clamping area at the front end of the bending die, make the clamping pad fit with the clamping block, and the pipe pushing mechanism pushes the pipe blank until it is aligned with the front end positions of the two pads; (3) Perform the first bending. After the bending die, the clamping block, and the boosting block horizontally move along the slide rail to press the pipe blank, the bending die and the clamping block rotate on the same rotation axis, and the angle of each single bending is half of the central angle of the bending die. During the bending process, the boosting block axially translates forward along with the pipe blank; (4) After the first bending is completed, the bending die, the clamping block, and the boosting block move away from the pipe blank along the slide rail, and the bending die and the clamping block return to the horizontal position through the rotation of the rotation axis. At the same time, the pads are removed and no longer used. Perform the second bending. Starting from the second bending action, each subsequent bending action is the same as the first bending, except that there is no participation of the bending die pad and the clamping pad; (5) Next, repeat the above second bending action according to the actual bending angle of the member. After completion, finally, cut off the straight section at the front end of the bending member using a cutting machine to obtain the final finished product.

2. The method according to claim 1, wherein The bending angle range of the bending member is 0 - 360°.

3. The method according to claim 1, wherein The radius of curvature of the formed member is 1 m or more.

4. The method according to claim 1, wherein Each bending section is continuous and there is no straight section in the middle, forming a continuous large formed angle member.

5. The method according to claim 1, wherein The bending angle of the component is , and the angle of a single bend is . During a single complete bending process, the advancement distance of the tube blank is ; If cannot be divided evenly by , then the bending angle of the last section is set to: the remainder obtained , and the advancement distance of the last section of the tube blank is L ; In the formula: is the bending radius of the component, with the unit of mm; is half of the central angle of the bending die, with the unit of "°"; is the bending angle of the component, with the unit of "°"; is 's remainder, with the unit of "°".

6. The method according to claim 1, wherein The central angle of the sector is selected within the range of 60° - 90°.

7. The method according to claim 1, wherein On one side where the clamping block (5) cooperates with the bending die (1), there is a second semi-circular groove with the same curvature radius R and the same radius r as the bending die (1). The central angle of the second semi-circular groove is , which is half of the central angle of the bending die (1), ensuring that the clamping block (5) and the bending die (1) can fit together completely. The radius of the second semi-circular groove of the clamping block (5) is r, where r is the radius of the tube blank. The clamping block (5) and the bending die (1) can jointly clamp the tube blank (2) and rotate simultaneously along the same rotation axis, ensuring that the tube blank (2) bends smoothly in the forming area.

8. The method according to claim 1, characterized in that A third semi-circular groove is provided on one side of the boosting block (4). The third semi-circular groove is arranged on the side facing the tube blank (2), and the radius of the third semi-circular groove is r. The boosting block (4) feeds axially while the bending die (1) rotates, ensuring that the tube blank (2) bends stably in the forming area under the action of the bending die.

9. The method according to claim 1, wherein The bending die spacer block (7) is assembled between the first semi-circular groove of the bending die (1) and the clamping spacer block (6), and is detachably fixed together with the bending die (1). One side of the bending die spacer block (7) that cooperates with the first semi-circular groove is composed of a semi-circular protrusion with a radius of r. One side of the bending die spacer block (7) that cooperates with the clamping spacer block (6) is a fourth semi-circular groove with a radius of r; correspondingly, one side of the clamping spacer block (6) that cooperates with the bending die spacer block (7) is provided with a fifth semi-circular groove. The space formed by the fourth semi-circular groove and the fifth semi-circular groove with the same diameter as the tube blank can clamp the tube blank; the other side of the clamping spacer block (6) is set as an arc surface with the same curvature as the second semi-circular groove; it is detachably fixed together with the second semi-circular groove of the clamping block (5) by this arc surface.

10. The method according to claim 1, wherein S = S’, S1 = S1’, S2 = S2’. S is the maximum distance from the tangent line of the center point of the bending die (1) to the bending die (1). S’ is the horizontal width of the front end of the bending die spacer block (7); S1 is the difference in the horizontal widths of the front end and the rear end of the clamping block (5). S2 is the axial length of the clamping block (5); S1’ is the horizontal width of the rear end of the clamping spacer block (6), and S2’ is the axial length of the clamping spacer block (6).

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