Pipe cutting machine and cutting method thereof

Abstract

The pipe cutting machine comprises a machine body, a rotating disc is arranged on the machine body, one or more cutting devices are arranged on the rotating disc, each cutting device comprises a servo electric cylinder, a swing arm and a cutter, the servo electric cylinder is in driving connection with one end of the swing arm, the other end of the swing arm is connected with the cutter, and the swing arm is arranged on the rotating disc in a swinging mode. The rotating disc is provided with a first through hole for a pipe to pass through. According to the pipe cutting machine, the servo electric cylinder, the swing arm and the cutter are arranged, the cutter is tightly attached to the pipe after making contact with the pipe or retreats under the action of the pipe, so that the position of the servo electric cylinder on the rotating disc is changed, the ovality of the pipe is detected, a new cam curve is generated according to a basic cam curve of the ovality of the pipe, and the pipe cutting efficiency is improved. And then the cutter is engaged with the rotating disc according to the new cam curve for feeding, the feeding is circulated until the pipe is cut off, the cutting mode can ensure that the cutter can normally cut off the pipe, and the phenomenon that the pipe is not cut off is also avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe cutting, and in particular to a pipe cutting machine and a cutting method thereof. Background Art

[0002] During the production process, pipes need to be cut. Pipes are generally cut by cutting machines. When the pipe diameter is large, the ovality deviation of the pipe will be large. There are certain requirements for the ovality of pipe products. After the pipe is cut, the product must meet the ovality requirements. In addition, for pipes with large ovality deviations, the pipe may not be cut correctly, or the pipe may not be cut continuously. Sometimes, embossing may appear on the surface of the pipe after cutting. The above problems may eventually cause the cut pipe to become waste.

[0003] Therefore, further improvements are necessary. Summary of the Invention

[0004] The purpose of the present invention is to provide a pipe cutting machine and a cutting method thereof with simple structure, good cutting effect, high production efficiency, good product quality and strong practicality, so as to overcome the shortcomings of the prior art.

[0005] A pipe cutting machine designed for this purpose includes a machine body, and is characterized in that: a turntable is provided on the machine body, and one or more cutting devices are provided on the turntable, and the cutting devices include a servo electric cylinder, a swing arm and a cutter. The servo electric cylinder is driven to connect one end of the swing arm, and the other end of the swing arm is connected to the cutter. The swing arm is swingably provided on the turntable, and a first through hole for the pipe to pass through is provided on the turntable; the servo electric cylinder drives the cutter forward or backward relative to the pipe through the swing arm. When the cutter advances toward the pipe at a limited speed, the cutter contacts the pipe and then adheres to the pipe or retreats under the action of the pipe, so as to change the position of the servo electric cylinder on the turntable, thereby realizing the detection of the ovality of the pipe.

[0006] The output end of the servo electric cylinder is provided with a connector, a first rotating shaft is provided on the connector, a first rotating hole is provided at one end of the swing arm, the first rotating shaft is rotatably connected to the first rotating hole, so that one end of the swing arm is rotatably connected to the connector.

[0007] The cutter is provided with a second rotating shaft, the other end of the swing arm is provided with a second rotating hole, the second rotating shaft is rotatably connected to the second rotating hole, so that the other end of the swing arm is rotatably connected to the cutter.

[0008] A third rotating shaft is provided on the turntable, a third rotating hole is provided on the swing arm, and the third rotating shaft is rotatably connected to the third rotating hole so that the swing arm is rotatably provided on the turntable.

[0009] The rotating seat is arranged on the rotating disc, the servo cylinder is fixed on the rotating seat, the fourth rotating shaft is arranged on the rotating disc, the fourth rotating hole is arranged on the rotating seat, and the fourth rotating shaft is rotationally connected with the fourth rotating hole, so that the rotating seat is rotationally arranged on the rotating disc.

[0010] The driving device is arranged on the machine body, the driving device comprises a motor and a gear assembly, the motor is drivingly connected with the gear assembly, the gear assembly is drivingly connected with the rotating disc, and the motor drives the rotating disc to rotate through the gear assembly.

[0011] The pipe clamping device is further arranged on the machine body, the pipe clamping device comprises a cylinder, a rotating arm and a clamping ring, one end of the rotating arm is drivingly connected with the cylinder, the other end of the rotating arm is drivingly connected with the clamping ring, the second through hole for the pipe to pass through is arranged on the clamping ring, and the cylinder drives the clamping ring to stretch out and retract in and out through the rotating arm, so as to adjust the size of the second through hole.

[0012] The clamping ring comprises a plurality of annularly distributed stretchable arms, the plurality of stretchable arms are enclosed into an annular shape, and adjacent two stretchable arms are rotationally connected with each other.

[0013] More than one servo control device is arranged on the rotating disc, the servo control device is in one-to-one correspondence with the cutting device, and the servo control device is electrically connected with the servo cylinder.

[0014] A pipe cutting method of a pipe cutting machine designed for the purpose, characterized in that it comprises the following steps: 1. Start the servo cylinder, rotate the rotating disc, and cut the cutter in torque mode, when the servo feedback torque exceeds the set torque threshold value, and the cutter position is within the corresponding specification threshold range of the pipe, it represents that the cutter has reached the surface of the pipe. 2. The rotating disc is in a rotating state, the cutter servo position is recorded every certain angle, and the total number is 360° of the rotating disc. 3. After the cutter servo position is recorded, the ovality of the pipe is obtained, all the recorded points form a basic cam curve with the X axis as the rotating disc angle and the Y axis as the cutter servo position, the cam curve is operated, and a new cam curve is generated. 4. After the new cam curve is generated, the mode of the cutter is changed to the position mode, and the cutter is engaged with the rotating disc according to the planned cam curve. 5. When the rotating disc is about to reach 360°, the cam curve is re-operated, and the corresponding cutting amount is added to the last cutting position to update the cam curve. 6. The cutter continues to cut according to the new cam curve, and the cutting is repeated in this way, the corresponding cutting amount is added to each point of each circle, and the pipe is cut off until the cutting reaches the pipe cutting position. 7) After the pipe is cut, the cutter retracts and the turntable stops rotating, and the entire cutting process is completed.

[0015] The pipe cutting machine of the present invention is provided with a servo electric cylinder, a swing arm and a cutter. After the cutter contacts the pipe, it sticks to the pipe or retreats under the action of the pipe to change the position of the servo electric cylinder on the turntable, thereby realizing the detection of the ovality of the pipe, and then generating a new cam curve according to the basic cam curve of the pipe ovality. Then the cutter engages with the turntable according to the new cam curve and feeds the cutter, and feeds the cutter in a cycle until the pipe is cut. This cutting method can ensure that the cutter can cut the pipe normally and avoid the phenomenon of the pipe being cut continuously. The cut pipe product meets the ovality requirements and there will be no imprint on its surface, thereby improving the product quality and the product qualification rate. It is particularly suitable for cutting large-diameter pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the overall structure of a pipe cutting machine in one embodiment of the present invention.

[0017] Figure 2 Schematic diagram of a partial structure of a pipe cutting machine in one embodiment of the present invention.

[0018] Figure 3 Schematic diagram of the assembly structure of the cutting device and the turntable in one embodiment of the present invention.

[0019] Figure 4 Schematic diagram of the assembly structure of the cutting device and the turntable in another orientation in one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the assembly structure of the cutting device and the third position of the turntable in one embodiment of the present invention.

[0021] Figure 6 Schematic diagram of the overall structure of a pipe clamping device in one embodiment of the present invention.

[0022] Figure 7 2 is a schematic diagram of the overall structure of the pipe clamping device in another aspect in one embodiment of the present invention.

[0023] Figure 8 Schematic diagram of the overall structure of the swing arm in one embodiment of the present invention.

[0024] Figure 9 Schematic diagram of the overall structure of the servo electric cylinder in one embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] See also Figures 1-9The pipe cutting machine includes a body 1, a turntable 2 is provided on the body 1, and one or more cutting devices 3 are provided on the turntable 2. The cutting device 3 includes a servo electric cylinder 4, a swing arm 5 and a cutter 6. The servo electric cylinder 4 drives and connects one end of the swing arm 5, and the other end of the swing arm 5 is connected to the cutter 6. The swing arm 5 is swingably set on the turntable 2, and a first through hole 7 for the pipe to pass through is provided in the center of the turntable 2; the servo electric cylinder 4 drives the cutter 6 to move forward or backward relative to the pipe through the swing arm 5. When the cutter 6 moves toward the pipe at a limited speed, the cutter 6 contacts the pipe and then sticks to the pipe or retreats under the action of the pipe to change the position of the servo electric cylinder 4 on the turntable 2, thereby realizing the detection of the ovality of the pipe; the above-mentioned feeding method is torque mode feeding. In torque mode, the feeding speed is set to fast feeding, and the feeding speed is limited to 50mm / s. When the cutter 6 touches the pipe, When encountering an oval convexity of the pipe, the torque of the cutter 6 is greater than the set torque, and the cutter 6 will be pushed back by the pipe (i.e., the cutter 6 retreats), and the servo feedback position changes (i.e., the position of the servo electric cylinder 4 on the turntable 2 changes). When encountering an oval concavity of the pipe, the torque of the cutter 6 is less than the set torque, and the cutter 6 will advance and touch the pipe tightly, and the servo feedback position will also change. The torque mode requires setting a torque threshold (when the cutter 6 encounters the pipe, it will not cut into it, but only mark it). The cutter 6 will advance rapidly, and the feedback torque of the servo electric cylinder 4 reaches the threshold. At the same time, it is determined whether the extended position of the cutter 6 reaches the specification threshold range corresponding to the pipe. If it has reached it, it indicates that the cutter 6 has reached the pipe surface. When the pipe is oval, because the cutter has encountered the pipe and the torque threshold has been set, the cutter 6 will be pushed back (i.e., the cutter 6 retreats).

[0027] The output end of the servo electric cylinder 4 is provided with a connector 8, on which a first rotating shaft 9 is provided. A first rotating hole 10 is provided at one end of the swing arm 5. The first rotating shaft 9 is rotatably connected to the first rotating hole 10 so that one end of the swing arm 5 is rotatably connected to the connector 8.

[0028] A second rotating shaft 11 is provided on the cutter 6, and a second rotating hole 12 is provided at the other end of the swing arm 5. The second rotating shaft 11 is rotatably connected to the second rotating hole 12, so that the other end of the swing arm 5 is rotatably connected to the cutter 6, that is, the cutter 6 rotates at the other end of the swing arm 5, ensuring that the cutter 6 can cut the pipe smoothly.

[0029] A third rotating shaft 13 is provided on the turntable 2, and a third rotating hole 14 is provided on the swing arm 5. The third rotating shaft 13 is rotatably connected to the third rotating hole 14 so that the swing arm 5 is rotatably set on the turntable 2. The servo electric cylinder 4 drives the swing arm 5 to swing on the turntable 2, and the swing arm 5 drives the cutter 6 to move forward or backward relative to the pipe.

[0030] A rotating base 15 is provided on the turntable 2, and the servo electric cylinder 4 is fixed on the rotating base 15. A fourth rotating shaft 25 is provided on the turntable 2, and a fourth rotating hole 16 is provided on the rotating base 15. The fourth rotating shaft 25 is rotatably connected to the fourth rotating hole 16, so that the rotating base 15 is rotatably set on the turntable 2, and then the servo electric cylinder 4 is swingably set on the turntable 2; when the servo electric cylinder 4 drives the cutter 6 forward or backward relative to the pipe through the swing arm 5, the servo electric cylinder 4 swings on the turntable 2, and then the position of the servo electric cylinder 4 on the turntable 2 can be changed.

[0031] A driving device is provided on the body 1, and the driving device includes a motor 17 and a gear assembly. The motor 17 drives the gear assembly, and the gear assembly is connected to the turntable 2. The motor 17 drives the turntable 2 to rotate through the gear assembly, and the turntable 2 is rotatably set on the body 1; the gear assembly includes a first gear 26 and a second gear 27 that are meshed with each other. The motor 17 drives the first gear 26, and the second gear 27 is connected to the turntable 2; the motor 17 is a servo motor, or the motor 17 is an asynchronous motor that can use encoder feedback, and the encoder feedback signal is connected to the PLC.

[0032] The machine body 1 is also provided with a pipe clamping device 18, which is located on both sides of the turntable 2. The pipe clamping device 18 includes a cylinder 19, a rotating arm 20 and a clamping ring 24. The cylinder 19 drives one end of the rotating arm 20, and the other end of the rotating arm 20 is driven to connect the clamping ring 24. The clamping ring 24 is provided with a second through hole 21 for the pipe to pass through. The cylinder 19 drives the clamping ring 24 to extend and retract inward and outward through the rotating arm 20 to adjust the size of the second through hole 21, thereby clamping or loosening the pipe, and can be applicable to pipes of different diameters. The clamping ring 24 clamps the pipe when the pipe is cut and loosens the pipe when the pipe is transported.

[0033] The clamping ring 24 includes a plurality of telescopic arms 22 distributed in a ring, and the plurality of telescopic arms 22 form a ring. Adjacent telescopic arms 22 are hinged to each other, and the other end of the rotating arm 20 is rotatably connected to two adjacent telescopic arms 22; the clamping ring 24 also includes an intermediate arm 28, and adjacent telescopic arms 22 are rotatably connected to the intermediate arm 28, so that the adjacent telescopic arms 22 are hinged to each other, and a fifth rotating shaft 29 is provided on the intermediate arm 28, and a fifth rotating hole is provided on the body 1. The fifth rotating shaft 29 is rotatably connected to the fifth rotating hole, so that the intermediate arm 28 is rotatably set on the body 1; the cylinder 19 drives the rotating arm 20 to rotate, so that the rotating arm 20 drives each telescopic arm 22 to rotate and retract, thereby causing the clamping ring 24 to retract and retract inside and outside.

[0034] There is one or more servo control devices 23 provided on the turntable 2. The servo control devices 23 correspond one to one with the cutting devices 3. The servo control devices 23 are electrically connected to the servo electric cylinder 4. The servo control device 23 includes an electrical box and a servo controller provided in the electrical box. The servo controller is electrically connected to the servo electric cylinder 4. The servo controller controls the operation of the servo electric cylinder 4, thereby controlling the cutter 6 to accurately cut the pipe.

[0035] In this embodiment, two cutting devices 3 are provided, and the two cutting devices 3 are symmetrically arranged on the turntable 2 .

[0036] A two-dimensional coordinate system, referred to here as the tube coordinate system, is established on the tube cross section, with the tube center as the origin. The servo position of the servo cylinder 4 is calculated by multiplying the tube diameter and the position of the cutter 6 in this coordinate system by the mechanical structure scale factor (this factor applies to different tube specifications). This servo position of the cutter 6 on the tube surface can be calculated. Similarly, the servo position of the servo cylinder 4 can be used to calculate the position of the cutter 6 in this coordinate system, the tube diameter, and other parameters. The position of the servo cylinder 4 side can be converted to the cutter position in the tube coordinate system using the mechanical structure scale factor. The recorded point's position value is this value.

[0037] The cutting method of the pipe cutting machine includes the following steps: 1) Start the servo electric cylinder 4, the turntable 2 rotates, and the cutter 6 quickly feeds in torque mode. When the servo feedback torque exceeds the set torque threshold and the position of the cutter 6 is within the specification threshold range corresponding to the pipe, it means that the cutter 6 has reached the pipe surface; 2) Turntable 2 is in rotation, and the servo position of cutter 6 is recorded at a certain angle every time, and the total number of records is 360° rotation of the turntable; at this time, the PLC program starts to trace the points: 0 degree, position of cutter 6 (converted thickness) 1 degree, position of cutter (converted thickness) - 360 degree cutter position (converted thickness); when 360 degrees are scanned, turntable 2 rotates one circle according to the setting, and cutter 6 enters the pipe xmm, generating: 0 degree, cutter 6 position, 1 degree; cutter position + 1 / 360xmm 1 degree cutter 6 position + 2 / 360xmm... 360 degrees + xmm, generating a cam curve, and at the same time changing the mode of cutter 6 to position mode, and cutter 6 engages with turntable 2. 3) After the cutter 6 servo position is recorded, the ovality of the pipe is obtained. All the recorded points form a basic cam curve with the X axis as the turntable angle and the Y axis as the cutter 6 servo position. The cam curve is calculated to generate a new cam curve; 4) After the new cam curve is generated, the mode of cutter 6 is changed to position mode, and cutter 6 engages with turntable 2 and feeds according to the planned cam curve; 5) Every time the turntable 2 is about to reach 360°, the cam curve is recalculated, and the corresponding feed amount is added to the feed position of the previous circle to update the cam curve; 6) Cutter 6 continues to feed according to the new cam curve, and feeds in this way in a cycle, adding the corresponding feed amount to each point in each circle until the cutter reaches the pipe cutting position to cut the pipe; 7) After the pipe is cut, the cutter 6 retracts, the turntable 2 stops rotating, and the entire cutting process is completed.

[0038] Calculation of cutter feed amount: 1. In the pipe coordinate system, the depth of cutting by the cutter 6 when the turntable 2 rotates one circle is represented by b, and the unit is mm / r; 2. Set y = f (x) as the function of converting the tube coordinate system to the servo position, x is the tube coordinate system position, and y is the servo position; As shown in the table below, the relationship between each feed is as follows: (x1, x2, ..., y1, y2, ... are each recording point) The servo positions of all original recorded points are converted into the cutter 6 position values ​​in the tube coordinate system, and the actual tube diameter corresponding to each recorded point is obtained. The ovality of the tube is visually displayed on the screen, making it convenient for operators to use the roundness calibrator to perform roundness adjustments on the upstream production line.

[0039] The above is a preferred embodiment of the present invention, which illustrates and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A pipe cutting machine, comprising a body (1), characterized in that: A turntable (2) is provided on the machine body (1), and one or more cutting devices (3) are provided on the turntable (2). The cutting device (3) includes a servo electric cylinder (4), a swing arm (5) and a cutter (6). The servo electric cylinder (4) drives and connects one end of the swing arm (5), and the other end of the swing arm (5) is connected to the cutter (6). The swing arm (5) is swingably provided on the turntable (2), and a first through hole (7) for the pipe to pass through is provided on the turntable (2); the servo electric cylinder (4) drives the cutter (6) to advance or retreat relative to the pipe through the swing arm (5). When the cutter (6) advances toward the pipe at a limited speed, the cutter (6) contacts the pipe and then clings to the pipe or retreats under the action of the pipe, thereby changing the position of the servo electric cylinder (4) on the turntable (2), thereby realizing the detection of the ovality of the pipe.

2. The pipe cutting machine according to claim 1, characterized in that: The output end of the servo electric cylinder (4) is provided with a connector (8), a first rotating shaft (9) is provided on the connector (8), a first rotating hole (10) is provided at one end of the swing arm (5), and the first rotating shaft (9) is rotatably connected to the first rotating hole (10), so that one end of the swing arm (5) is rotatably connected to the connector (8).

3. The pipe cutting machine according to claim 2, characterized in that: The cutter (6) is provided with a second rotating shaft (11), and the other end of the swing arm (5) is provided with a second rotating hole (12). The second rotating shaft (11) is rotatably connected to the second rotating hole (12), so that the other end of the swing arm (5) is rotatably connected to the cutter (6).

4. The pipe cutting machine according to claim 3, characterized in that: A third rotating shaft (13) is provided on the turntable (2), a third rotating hole (14) is provided on the swing arm (5), and the third rotating shaft (13) is rotatably connected to the third rotating hole (14) so ​​that the swing arm (5) is rotatably provided on the turntable (2).

5. The pipe cutting machine according to claim 1, characterized in that: A rotating seat (15) is provided on the turntable (2), the servo electric cylinder (4) is fixed on the rotating seat (15), a fourth rotating shaft (25) is provided on the turntable (2), a fourth rotating hole (16) is provided on the rotating seat (15), and the fourth rotating shaft (25) is rotatably connected to the fourth rotating hole (16) so that the rotating seat (15) is rotatably provided on the turntable (2).

6. The pipe cutting machine according to claim 1, characterized in that: A driving device is provided on the machine body (1), and the driving device includes a motor (17) and a gear assembly. The motor (17) drives the gear assembly, and the gear assembly is connected to the turntable (2). The motor (17) drives the turntable (2) to rotate through the gear assembly.

7. The pipe cutting machine according to claim 1, characterized in that: The body (1) is also provided with a pipe clamping device (18), which includes a cylinder (19), a rotating arm (20) and a clamping ring (24). The cylinder (19) is driven to connect one end of the rotating arm (20), and the other end of the rotating arm (20) is driven to connect the clamping ring (24). The clamping ring (24) is provided with a second through hole (21) for the pipe to pass through. The cylinder (19) drives the clamping ring (24) to expand and contract inward and outward through the rotating arm (20) to adjust the size of the second through hole (21).

8. The pipe cutting machine according to claim 7, characterized in that: The clamping ring (24) includes a plurality of telescopic arms (22) distributed in an annular shape. The plurality of telescopic arms (22) enclose a ring. Two adjacent telescopic arms (22) are hinged to each other. The other end of the rotating arm (20) is rotatably connected to two adjacent telescopic arms (22).

9. The pipe cutting machine according to claim 1, characterized in that: One or more servo control devices (23) are provided on the turntable (2), the servo control devices (23) correspond to the cutting devices (3) one by one, and the servo control devices (23) are electrically connected to the servo electric cylinder (4).

10. The cutting method of the pipe cutting machine according to any one of claims 1 to 9, characterized in that: The following steps are involved: 1) Start the servo electric cylinder (4), the turntable (2) rotates, and the cutter (6) feeds quickly in torque mode. When the servo feedback torque exceeds the set torque threshold and the position of the cutter (6) is within the specification threshold range corresponding to the pipe, it means that the cutter (6) has reached the surface of the pipe; 2) The turntable (2) is in a rotating state, and the servo position of the cutter (6) is recorded at a certain angle, and the total number of records is 360° rotation of the turntable; 3) After the cutter (6) servo position is recorded, the ovality of the pipe is obtained. All the recorded points form a basic cam curve with the X axis being the turntable angle and the Y axis being the cutter (6) servo position. The cam curve is calculated to generate a new cam curve. 4) After the new cam curve is generated, the mode of the cutter (6) is changed to the position mode, and the cutter (6) engages with the turntable (2) according to the planned cam curve to perform cutting; 5) Each time the turntable (2) is about to rotate 360°, the cam curve is recalculated, and the corresponding feed amount is added to the feed position of the previous circle to update the cam curve; 6) The cutter (6) continues to feed according to the new cam curve, and feeds in this way in a cycle, adding the corresponding feed amount to each point in each circle until the cutter reaches the pipe cutting position to cut the pipe; 7) After the pipe is cut, the cutter (6) is retracted and the turntable (2) stops rotating, and the entire cutting process is completed.

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