A flexible clamping and bending forming device and forming method for a pipe bending robot

Abstract

The present invention discloses a flexible clamping and bending forming device and forming method for a pipe bending robot, comprising a flexible clamping device and a bending device; the flexible clamping device comprises a first fixing groove and a first rubber airbag fixed in the first fixing groove; the bending device comprises a second fixing groove, a second rubber airbag fixed in the second fixing groove, and a bending die. By innovatively designing a traditional rigid linear clamping device into a flexible clamping device capable of matching straight sections or complex curved sections, the robot pipe bending forming process can form features such as "straight section + curved section + straight section" and "straight section + curved section + curved section + straight section + straight section". The clamping section is an air pressure controllable inflatable rubber airbag structure. Through the air pressure control system, the clamping force of the clamping part during pipe bending can be adjusted, thereby improving the forming performance of the pipe and further expanding the application range of the robot pipe bending forming technology.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe bending and forming processing, and in particular to a flexible clamping and bending forming device of a pipe bending robot and a forming method. Background Art

[0002] Robotic tube bending technology is an important technological innovation in recent years that combines traditional manufacturing processes with robotic technology. This technology combines traditional bending technology with a six-axis industrial robot. By controlling the spatial motion trajectory of the terminal bending forming device and cooperating with an external rotary clamping device, it can achieve the overall precise and rapid forming of slender bent tubes with various complex spatial axes and multiple bending radius configurations.

[0003] Because robotic bending is based on the principle of round-bending, clamping segments are unavoidable. Traditional clamping devices typically use rigid straight-segment clamping, making them suitable for forming spatial components that consist of "straight + curved + straight" segments. For spatial components that consist of "straight + curved + curved + straight," there's no straight segment between the two curved segments to clamp, so a custom clamping die must be customized to match the complex axis of the previous curved segment. When forming multiple, continuous, multi-curved features, multiple sets of specialized clamping dies are required. These dies must also be disassembled, assembled, and replaced based on the different curved segments being formed, severely impacting the forming efficiency and automation level of the bending robot. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art and the forming characteristics of the robot tube bending forming technology, the present invention provides a flexible clamping bending forming device and forming method for a tube bending robot, so that during the tube bending forming process, the flexible clamping device of the tube bending robot can accurately follow the shape changes of the formed bent section and is no longer limited to clamping the straight section. At the same time, the flexible clamping device adopts an inflatable rubber airbag structure, and the airbag fully fits the outside of the pipe, so that the force is more uniform, and the external clamping force of the clamping section is adjustable when the pipe is bent. It can be used for the one-time forming of spatial bending components such as "straight section + bent section + straight section" or "straight section + bent section + bent section + straight section", effectively avoiding the problems of designing, manufacturing and replacing multiple sets of special molds with complex structures.

[0005] The present invention adopts the following technical solutions:

[0006] A flexible clamping and bending forming device for a pipe bending robot comprises a flexible clamping device (11) and a bending device (12); the flexible clamping device (11) comprises a first fixing groove (111) and a first rubber airbag (112) fixed in the first fixing groove (111); the bending device (12) comprises a second fixing groove (121), a second rubber airbag (122) fixed in the second fixing groove (121), and a bending die (123). The first fixing groove (111) and the second fixing groove (121) confine the first rubber airbag (112) and the second rubber airbag (122) within a certain area. The first rubber airbag (112) and the second rubber airbag (122) are both exposed to a certain height from the first fixing groove (111) and the second fixing groove (121). The exposed parts of the first rubber airbag (112) and the second rubber airbag (122) are opposite and closely attached to each other. An internal cavity having the same shape as the clamping section is formed according to the shape of the clamping section. An air inlet is provided on the first rubber airbag (112) and the second rubber airbag (122). The air inlet is connected to one end of an air inlet pipe, and the other end of the air inlet pipe is connected to an air pressure control system. The air pressure control system controls the pressure inside the second fixing groove (121), applies different pressures to different parts of the pipe section, and realizes flexible clamping of the pipe section.

[0007] The flexible clamping and bending forming device of the pipe bending robot is made of metal, and a circular hole is opened at the bottom of the groove to reserve a position for the airbag air inlet hole and play a fixing role.

[0008] The flexible clamping and bending forming device of the pipe bending robot, the first rubber airbag (112) and the second rubber airbag (122) are hollow structures, and an air inlet is set on the airbag, which cooperates with the circular hole at the bottom of the fixing groove (121) to fix the airbag in the groove.

[0009] In the flexible clamping and bending forming device for a pipe bending robot, the air inlet of the second rubber airbag (122) is configured as an external thread structure, and the airbag can be tightly fixed in the fixing groove (121) by a nut.

[0010] According to any of the forming methods of the flexible clamping bending forming device, the forming method comprises the following steps:

[0011] (1) Determine the material type of the robot-bent tube (2) and the yield strength σ of the tube (2) material s , pipe outer diameter D, pipe wall thickness t;

[0012] (2) According to the type of material selected, the friction coefficient μ between the first rubber airbag 112, the second rubber airbag 122 and the pipe (2) is measured, and the minimum pressure P required for the first rubber airbag (112) and the second rubber airbag (122) to clamp the pipe (2) is calculated. min and maximum pressure P max The minimum pressure is the pressure that keeps the rubber airbag (112) (122) and the pipe (2) from sliding relative to each other during the bending process; the maximum pressure is the pressure that keeps the clamping section pipe (2) from deforming under the pressure of the first rubber airbag (112) and the second rubber airbag (122); both the minimum pressure and the maximum pressure can be obtained through experiments;

[0013] (3) According to the spatial geometric configuration of the formed component, a process analysis is performed, and each formed part is divided into a "straight section" and a "bend section", and the clamping position and clamping pressure of each part are determined; since the pipe (2) is bent under the action of the bending moment, the bending moment is first calculated for the bending part, and the bending moment is calculated using the following formula: Among them, k0 is the relative strength coefficient of the material; σ s is the material yield strength limit; D is the outer diameter of the pipe; t is the wall thickness of the pipe; d is the inner diameter of the pipe; ρ is the bending radius. Using the obtained moment M, the formula l is the distance from the midpoint of the clamping section axis to the bending center axis, and the required clamping force is calculated; finally, the contact area and pressure are determined according to the contact form between the first rubber airbag (112), the second rubber airbag (122) and the pipe (2). The contact area is 1 / 2 of the outer diameter section circumference multiplied by the axis length of the clamping part: S = πDl m / 2, the final pressure is

[0014] (4) The air pressure control system sets a process curve for the pressure of each part calculated according to the shape characteristics of each section, and moves to each designated position in coordination with the bending process curve of the robot to achieve clamping and bending of the pipe (2);

[0015] (5) By changing the position of the terminal forming device (1) and the pressure of the clamping device (11), a one-time bending forming of a complex continuous multi-bend spatial component is achieved.

[0016] Compared with the existing technology, the present invention has the following beneficial effects: the present invention proposes a flexible clamping and bending forming device and forming method for a pipe bending robot, and innovatively designs the traditional rigid linear clamping device into a flexible clamping device that can match straight sections or complex curved sections, so that the robot pipe bending forming process can form both "straight section + curved section + straight section" features and "straight section + curved section + curved section + straight section + straight section" features, and the clamping section is an air pressure controllable inflatable rubber airbag structure, which realizes the adjustable clamping force of the clamping part during pipe bending and forming through the air pressure control system, thereby improving the forming performance of the pipe and further expanding the application scope of the robot pipe bending forming technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of a robot bending forming system and end device in the background art;

[0018] Figure 2 Schematic diagram of the flexible clamping device structure for the tube bending robot (a) and the calculation diagram of the clamping force during bending (b);

[0019] Figure 3 Schematic diagram of the changes in the flexible clamping device for the pipe bending robot;

[0020] Figure 4 Schematic diagram of the “straight section + curved section + straight section” bending process;

[0021] Figure 5 Schematic diagram of the bending process of "straight section + curved section + curved section + straight section";

[0022] In the figure: 1. End forming device, 11. Flexible clamping device, 111. First fixing groove, 112. First rubber airbag, 12. Bending die, 121. Second fixing groove, 122. Second rubber airbag, 123. Bending die, 13. Pressing device, 2. Tubing; DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to specific embodiments.

[0024] like Figure 2-5As shown, a flexible clamping and bending device for a pipe bending robot is disclosed, comprising a flexible clamping device 11 and a bending device 12. The flexible clamping device 11 includes a first fixing groove 111 and a first rubber airbag 112 fixed within the first fixing groove 111. The bending device 12 includes a second fixing groove 121, a second rubber airbag 122 fixed within the second fixing groove 121, and a bending die 123. The first and second fixing grooves 111 and 121 confine the first and second rubber airbags 112 and 122 to a certain area. The first and second rubber airbags 112 and 122 are each exposed to a certain height from the first and second fixing grooves 111 and 121. The exposed portions of the first and second rubber airbags 112 and 122 face each other and are tightly attached to each other. Based on the shape of the clamping section, an internal cavity with the same shape as the clamping section is formed adaptively. The rubber airbags 112 and 122 are provided with air inlets, which are connected to one end of an air intake pipe, the other end of which is connected to an air pressure control system. The pressure inside the second fixing groove 121 is controlled by its air pressure control system, and different pressures are applied to different parts of the pipe section to achieve flexible clamping of the pipe section.

[0025] The first fixing groove 111 and the second fixing groove 121 are made of metal, and a round hole is opened at the bottom of the groove to reserve a position for the airbag air inlet hole and play a fixing role.

[0026] The first rubber airbag 112 and the second rubber airbag 122 are hollow structures, and air inlets are provided on the airbags. The air inlets cooperate with the circular holes at the bottom of the fixing groove 121 to fix the airbags in the grooves.

[0027] The air inlet of the second rubber airbag 122 is configured as an external thread structure, and the airbag can be tightly fixed in the fixing groove 121 by a nut.

[0028] The first rubber airbag 112 and the second rubber airbag 122 can flexibly change according to the shape of the clamped pipe section. They can clamp not only straight sections but also curved sections. The pressure can be adjusted in real time according to the shape of the clamped section to avoid sliding of the clamped section and cross-sectional distortion of the pipe section caused by pressure.

[0029] The present invention relates to a robot bending forming method of the flexible clamping device, which is characterized by comprising the following steps:

[0030] (1) Determine the material type of the robot bending tube 2 as 20 steel and determine the yield strength σ s =240MPa, outer diameter D=8mm, wall thickness t=1mm;

[0031] (2) According to the type of material selected, the friction coefficient μ between the first rubber airbag 112, the second rubber airbag 122 and the pipe 2 is measured, and the minimum pressure P required for the first rubber airbag 112 and the second rubber airbag 122 to clamp the pipe 2 is calculated. min and maximum pressure P max The minimum pressure is the pressure that keeps the first rubber airbag 112, the second rubber airbag 122, and the tube 2 from sliding relative to each other during the bending process; the maximum pressure is the pressure that prevents the clamping section of the tube 2 from deforming under the pressure of the first rubber airbag 112 and the second rubber airbag 122. Both the minimum pressure and the maximum pressure can be obtained through experiments.

[0032] (3) According to the spatial geometric configuration of the formed component, the process analysis is carried out, and the forming parts are divided into "straight sections" and "bend sections". The clamping position and clamping pressure of each part are determined. Since the pipe 2 is bent under the action of the bending moment, the bending moment is first calculated for the bending part. The following formula is used to calculate the bending moment: Where, k0 = 11.6 mm; σ s =240MPa; D = 8mm; t = 1mm; d = 6mm; ρ = 40mm. ① Pressure value of the straight line segment: Bending moment M = 17.4N·m, using the formula l is the distance from the midpoint of the clamped straight section to the center axis of the bend. The contact area is 1 / 2 of the outer diameter section circumference multiplied by the axial length of the clamped straight section. S = πDl m / 2=π×8×50 / 2=628mm 2 , ② Pressure value of the bending section: bending moment M = 17.4N·m, using the formula l is the distance from the midpoint of the clamping bend to the central axis of the bend. The contact area is 1 / 2 of the outer diameter section circumference multiplied by the axial length of the clamping bend. S = πDl m / 2=π×8×37 / 2=464.9mm 2 ,

[0033] (4) The air pressure control system sets the process curve of each part according to the pressure calculated by the shape characteristics of each section, and moves to each designated position in coordination with the bending process curve of the robot to achieve clamping and bending of the pipe 2.

[0034] (5) By changing the position of the terminal forming device 1 and the pressure of the clamping device 11, a one-time bending forming of a complex continuous multi-bend spatial component can be achieved.

[0035] like Figure 4As shown, when the clamping section is a straight section, the flexible clamping device 11 cooperates with the bending device 12 to clamp the straight section. The first rubber airbag 112 and the second rubber airbag 122 adaptively form a linear cavity according to the shape of the clamping section. The air pressure control system adjusts the air pressure in the airbag to 1.1 MPa. The flexible clamping device 11 and the bending device 12 clamp the pipe 2 and move it linearly along the axis of the pipe 2. The pressing device 13 presses the pipe 2, forcing the pipe 2 to gradually stick to the mold to achieve the bending of the pipe 2.

[0036] like Figure 5 As shown, when there are multiple continuous bends (no straight line between two adjacent bends), the formed bend section serves as the clamping section. The first rubber airbag 112 and the second rubber airbag 122 adaptively form an arc-shaped cavity according to the shape of the clamping section. The air pressure control system adjusts the air pressure in the airbag to 2.0 MPa. The flexible clamping device 11 and the bending device 12 clamp the tube 2 and perform linear motion along the axial direction of the tube 2. The pressing device 13 presses the tube 2, forcing the tube 2 to gradually adhere to the mold, thereby achieving continuous multiple bend forming of the tube without changing the mold.

[0037] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A flexible clamping and bending forming device for a pipe bending robot, characterized in that: The invention comprises a flexible clamping device (11) and a bending device (12); the flexible clamping device (11) comprises a first fixing groove (111) and a first rubber airbag (112) fixed in the first fixing groove (111); the bending device (12) comprises a second fixing groove (121), a second rubber airbag (122) fixed in the second fixing groove (121), and a bending die (123); the first fixing groove (111) and the second fixing groove (121) restrict the first rubber airbag (112) and the second rubber airbag (122) to a certain area, and the first rubber airbag (112) and the second rubber airbag (122) are both exposed to the first fixing groove (111) and the second fixing groove (121). The fixed groove (121) has a certain height, and the exposed parts of the first rubber airbag (112) and the second rubber airbag (122) are opposite and tightly attached to each other, and an internal cavity with the same shape as the clamping section is formed according to the shape of the clamping section. The first rubber airbag (112) and the second rubber airbag (122) are provided with an air inlet, which is connected to one end of the air inlet pipe, and the other end of the air inlet pipe is connected to an air pressure control system; the air pressure control system controls the pressure inside the second fixed groove (121), applies different pressures to different parts of the pipe section, and realizes flexible clamping of the pipe section; and according to the type of the selected material, the friction coefficient between the first rubber airbag (112), the second rubber airbag (122) and the pipe (2) is measured. μ , and calculate the minimum pressure required for the first rubber airbag (112) and the second rubber airbag (122) to clamp the pipe (2) P min and maximum pressure P max The minimum pressure is the pressure that keeps the first rubber airbag (112), the second rubber airbag (122) and the pipe (2) from sliding relative to each other during the bending process; the maximum pressure is the pressure that keeps the clamping section pipe (2) from deforming under the pressure of the first rubber airbag (112) and the second rubber airbag (122); according to the spatial geometric configuration of the formed component, a process analysis is performed, and each forming part is divided into a "straight section" and a "bend section", and the clamping position and clamping pressure of each part are determined; since the pipe (2) is bent under the action of a bending moment, the bending moment is first calculated for the bending part, and the bending moment is calculated using the following formula: in, is the relative strength coefficient of the material; is the material yield strength limit: D is the outer diameter of the pipe; t is the pipe wall thickness; d is the inner diameter of the pipe; ρ is the bending radius; the torque obtained by M , using the formula , l The required clamping force is calculated as the distance from the midpoint of the clamping section axis to the bending center axis; finally, the contact area and the pressure are determined according to the contact form between the first rubber airbag (112), the second rubber airbag (122) and the pipe (2). The contact area is 1 / 2 of the circumference of the outer diameter section multiplied by the axis length of the clamping part: The final pressure is The air pressure control system sets the process curve of the pressure of each part calculated according to the shape characteristics of each section, and moves to each designated position in coordination with the bending process curve of the robot to achieve the clamping and bending of the pipe (2).

2. The flexible clamping and bending forming device of a pipe bending robot according to claim 1, characterized in that: The first fixing groove (111) and the second fixing groove (121) are made of metal, and a circular hole is opened at the bottom of the groove to reserve a position for the airbag air inlet hole and play a fixing role.

3. The flexible clamping and bending forming device of a pipe bending robot according to claim 1, characterized in that: The first rubber airbag (112) and the second rubber airbag (122) are hollow structures, and an air inlet is provided on the airbag. The air inlet cooperates with the circular hole at the bottom of the fixing groove (121) to fix the airbag in the groove.

4. The flexible clamping and bending forming device of a pipe bending robot according to claim 1, characterized in that: The air inlet of the second rubber airbag (122) is configured as an external thread structure, and the airbag can be tightly fixed in the fixing groove (121) by a nut.

5. The forming method of the flexible clamping bending forming device according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Determine the material type of the robot-bent tube (2) and the yield strength of the tube (2) σ s , pipe outer diameter D , pipe wall thickness t ; (2) According to the type of the selected material, the friction coefficient between the first rubber airbag (112), the second rubber airbag (122) and the pipe (2) is measured. μ , and calculate the minimum pressure required for the first rubber airbag (112) and the second rubber airbag (122) to clamp the pipe (2) P min and maximum pressure P max The minimum pressure is the pressure that keeps the rubber airbag (112) (122) and the tube (2) from sliding relative to each other during the bending process; the maximum pressure is the pressure that keeps the clamping section tube (2) from deforming under the pressure of the first rubber airbag (112) and the second rubber airbag (122); both the minimum pressure and the maximum pressure can be obtained through experiments; (3) According to the spatial geometric configuration of the formed component, the process analysis is carried out, and each forming part is divided into "straight section" and "bend section", and the clamping position and clamping pressure of each part are determined; since the pipe (2) is bent under the action of the bending moment, the bending moment is first calculated for the bending part, and the bending moment is calculated using the following formula: in, is the relative strength coefficient of the material; is the material yield strength limit: D is the outer diameter of the pipe; t is the pipe wall thickness; d is the inner diameter of the pipe; ρ is the bending radius; the torque obtained by M , using the formula , l The required clamping force is calculated as the distance from the midpoint of the clamping section axis to the bending center axis; finally, the contact area and the pressure are determined according to the contact form between the first rubber airbag (112), the second rubber airbag (122) and the pipe (2). The contact area is 1 / 2 of the circumference of the outer diameter section multiplied by the axis length of the clamping part: The final pressure is ; (4) The air pressure control system sets the process curve of each part according to the pressure calculated based on the shape characteristics of each section, and moves to each designated position in coordination with the bending process curve of the robot to achieve the clamping and bending of the pipe (2); (5) By changing the position of the terminal forming device (1) and the pressure of the clamping device (11), a one-time bending forming of a complex continuous multi-bend spatial component can be achieved.

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