CN112499393A

CN112499393A - Stranding machine with PLC constant tension control system

Info

Publication number: CN112499393A
Application number: CN202011222691.1A
Authority: CN
Inventors: 郑怀蜀; 周岳; 江超; 唐敏; 蒋鹏; 郑建国; 顾祝军; 周法查; 徐金虎; 王官德
Original assignee: Zhejiang Gengu Cable Co ltd
Current assignee: Zhejiang Gengu Cable Co ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-03-16
Anticipated expiration: 2040-11-05
Also published as: CN112499393B

Abstract

The invention provides a stranding machine with a PLC constant tension control system, which comprises a paying-off frame; the pay-off frame is provided with a bobbin positioning mechanism, and the bobbin positioning mechanism comprises a positioning disc, a movable disc and a power part; a servo motor is arranged on the pay-off frame, a tension control mechanism is arranged on the pay-off frame, and the tension control mechanism comprises a frequency converter, a tension detector, a rotary encoder and a PLC (programmable logic controller). When the pay-off device is used, the servo motor drives the wire barrel wound with the wire core to rotate in the circumferential direction, so that the purpose of active pay-off is achieved. The active paying-off has better adaptability, more uniform tension and easier control of the tension. In the process of initiatively paying off the line by the servo motor, the tension detector detects the tension of the line core and feeds the tension back to the PLC controller, the rotary encoder measures the rotating speed of the line barrel and feeds the rotating speed back to the PLC controller, and the PLC controller adjusts the rotating speed of the servo motor through the frequency converter to change the tension of the line core. So that the tension of the wire core is constant in the process of the wire coil from full coil to shallow coil.

Description

Stranding machine with PLC constant tension control system

Technical Field

The invention relates to a stranding machine, in particular to a stranding machine with a PLC constant tension control system.

Background

During the manufacturing process of the cable, the changes of the tension and the lay length directly affect the diameter and the mechanical strength of the cable, and have an influence on the mechanical performance and the electrical performance of the cable. Along with the development of the cable industry, the requirements of various novel cables on paying-off tension are stricter and stricter, the tension of a wire coil from a full coil to a shallow coil cannot be constant by the currently adopted open-loop tension control mode, and the industrial requirements cannot be met.

Disclosure of Invention

In view of the above, the present invention aims to provide a wire twisting machine with a PLC constant tension control system, which has the advantage of being able to achieve a constant tension of a wire coil from a full coil to a shallow coil.

In order to solve the technical problems, the technical scheme of the invention is as follows: a stranding machine with a PLC constant tension control system comprises a paying-off frame, wherein a wire barrel placing groove is formed in the surface of the paying-off frame, and a wire barrel wound with a wire core is placed in the wire barrel placing groove;

the pay-off frame is provided with a bobbin positioning mechanism which is used for positioning a bobbin in the bobbin placing groove; the bobbin positioning mechanism comprises a positioning disc, a movable disc and a power piece, the positioning disc is rotatably connected to the inner groove wall of the bobbin placing groove, the movable disc is rotatably connected to the inner groove wall of the bobbin placing groove, which is opposite to the positioning disc, and the power piece is used for driving the movable disc to move along the axial direction of the movable disc;

be provided with servo motor on the unwrapping wire frame, servo motor is used for the drive the positioning disk carries out circumferential direction, still includes tension control mechanism, tension control mechanism includes converter, tension detector, rotary encoder, PLC controller, and tension detector detects the tension of sinle silk and transmits signal to the PLC controller, rotary encoder detects the unwrapping wire speed of a line section of thick bamboo and transmits signal to the PLC controller, and the PLC controller passes through the converter control servo motor's rotational speed.

Through the technical scheme, during use, the line barrel wound with the line core is driven by the servo motor to rotate in the circumferential direction, so that the purpose of active paying-off is achieved. The active paying-off has the advantages of better adaptability, more uniform tension and easier control of the tension. Meanwhile, the active paying-off mode is adopted, so that the working efficiency can be improved, and the productivity of the cable can be improved. The capacity of the wire drum during active paying-off is 3-4 times of the capacity of the wire drum during passive paying-off, so that the replacement frequency of the wire drum can be reduced, the replacement time of the wire drum is saved, and the production efficiency is improved.

Through the in-process of servo motor initiative unwrapping wire, tension detector detects the tension of sinle silk to the accurate feedback of the tension of sinle silk feeds back to the PLC controller in the production process, rotary encoder is used for measuring the rotational speed of a line section of thick bamboo, and feeds back the accurate feedback of the linear velocity of sinle silk to the PLC controller in the production process, and the PLC controller passes through the rotational speed of converter adjustment servo motor, with the tension that changes the sinle silk. So that the tension of the wire core is constant in the process of the wire coil from full coil to shallow coil.

Preferably, a hysteresis clutch is further included which is mounted on the line frame.

Through above-mentioned technical scheme, through using hysteresis brake, can supply certain torque, effectively overcome the tension change that the initiative unwrapping wire in-process was aroused by the line barrel book footpath constantly change, reach the effect of tension accurate control.

Preferably, be provided with movable executive component on the unwrapping wire frame, movable executive component includes the actuating cylinder, sets up mounting panel on the actuating cylinder piston rod, servo motor installs on the mounting panel, movable executive component is used for the drive servo motor and the positioning disk moves along the axial machine of positioning disk.

Through above-mentioned technical scheme, when needs take out the spool from the spool standing groove, move towards the one side of keeping away from the spool standing groove through power component drive positioning disk for positioning disk and spool in the spool standing cavity separate. Then, the servo motor and the positioning disc are driven by the movable executing piece to move towards one side far away from the bobbin placing groove until the positioning disc is separated from the bobbin in the bobbin placing groove. At this moment, the movable disc and the positioning disc both relieve the limitation on the bobbin, and a worker can take out the bobbin from the bobbin placing groove conveniently.

Preferably, the paying-off device further comprises an outer cover covering the paying-off frame, a bobbin collecting chamber is formed between the outer cover and the paying-off frame, an opening is formed in the bottom of the outer cover, and the opening is communicated with the bobbin collecting chamber.

Through the technical scheme, when the bobbin needs to be taken out of the bobbin placing groove, the limiting of the bobbin positioning mechanism to the bobbin is firstly released, so that the bobbin can freely move in the bobbin placing groove. And then, the paying-off frame is controlled to rotate slowly, when the bobbin placing groove rotates to an inclined downward position, bobbins in the bobbin placing groove can enter the bobbin collecting chamber under the action of self weight, and when the bobbins are in contact with the inner wall of the outer cover, the bobbins can slide towards one side of the opening along the inner wall of the outer cover. When the bobbin slides to the opening, the bobbin can fall from the opening. So do not need the workman to take out the bobbin from the bobbin standing groove manually, replace the manual work through machinery, degree of automation can promote, and the productivity can improve.

Preferably, a rubber cushion pad is arranged on the inner wall of the outer cover.

Through above-mentioned technical scheme, the rubber buffer section that sets up in cover inner wall department is used for playing the cushioning effect to the line section of thick bamboo of whereabouts, can noise abatement's production, and can play the guard action to the dustcoat for the dustcoat is not fragile.

Preferably, a material storage cavity is formed in the pay-off frame, the material storage cavity is located on one side, close to the central line of the pay-off frame, of the bobbin placing groove, and the material storage cavity is communicated with the bobbin placing groove;

two groups of first limiting mechanisms are symmetrically arranged on the inner groove wall of the bobbin placing groove, which is far away from the material storage cavity, and are matched with each other to limit bobbins in the bobbin placing groove from entering the bobbin collecting cavity;

two groups of second limiting mechanisms are symmetrically arranged at the joint of the bobbin placing groove and the material storage cavity and are used for limiting bobbins in the material storage cavity from entering the bobbin placing groove;

two sets of third limiting mechanisms are symmetrically arranged on the inner wall of the stock cavity, the stock cavity is divided into a preparation section close to the bobbin placing groove and a storage section far away from the bobbin placing groove by the two sets of third limiting mechanisms, and the two sets of third limiting mechanisms are matched to limit the bobbins in the storage section from entering the preparation section.

Through the technical scheme, the plurality of bobbins to be used are placed in the material storage cavity, and the bobbins in the material storage cavity are sequentially arranged along the radial direction of the pay-off frame.

When the bobbin needs to be placed into the bobbin placing groove, the limiting effect of the second limiting mechanism is relieved, so that when the paying-off frame rotates in the circumferential direction, the bobbin located in the preparation section does centrifugal motion and enters the bobbin placing groove. Two sets of first stop gear cooperation that the symmetry set up are used for fixing a position a line section of thick bamboo for a line section of thick bamboo can stop between activity dish and positioning disk. The movable disc is driven by the power part to move towards the inside of the bobbin placing groove, so that the movable disc is inserted into the central circular hole of the bobbin, and the movable disc limits one side of the bobbin. Move towards the inside line section of thick bamboo standing groove through activity executive drive servo motor and positioning disk for during the positioning disk inserted the center round hole of a line section of thick bamboo, the positioning disk spacing to the opposite side of a line section of thick bamboo. And then the limiting function of the first limiting mechanism is removed, the second limiting mechanism is controlled to take effect, and the limiting function of the third limiting mechanism is removed, so that the bobbin positioned in the storage section can enter the preparation section in the circumferential rotation process of the pay-off frame to prepare for next bobbin replacement. The mechanical mechanism is used for replacing manual feeding, so that the automation degree of the stranding machine is improved, and the productivity of the stranding machine is improved.

Preferably, it is provided with first slide hole to run through on the unwrapping wire frame, first stop gear includes first stopper and the first actuating cylinder that drives, first stopper slide connect in the first slide hole, first stopper orientation one side of material stock cavity is provided with first locating slot, the first actuating cylinder that drives is installed on the unwrapping wire frame, just the first actuating cylinder that drives is used for driving first stopper in slide in the first slide hole.

Through the technical scheme, when the first limiting mechanism is required to be used for limiting the bobbin in the bobbin placing groove, the first limiting block is controlled to move towards the inside of the bobbin placing groove through the first driving cylinder until the first limiting block protrudes out of the inner groove wall of the bobbin placing groove. When the bobbin enters the bobbin placing cavity from the preparation section, one end of the bobbin can enter the first positioning groove and is tightly abutted against the inner groove wall of the first positioning groove, and the movement of the bobbin is limited at the moment.

Preferably, a second sliding hole is formed in the pay-off frame in a penetrating mode, the second sliding hole is communicated with the joint of the bobbin placing groove and the material storage cavity, the second limiting mechanism comprises a second limiting block and a second driving cylinder, the second limiting block is connected in the second sliding hole in a sliding mode, the second driving cylinder is installed on the pay-off frame, and the second driving cylinder is used for driving the second limiting block to slide in the second sliding hole.

Through the technical scheme, when the second limiting mechanism is used for limiting the bobbin, the second limiting block is controlled to move towards the joint of the bobbin placing groove and the material storage cavity through the second driving cylinder until the second limiting block protrudes out of the joint of the bobbin placing groove and the material storage cavity, and the bobbin in the bobbin placing groove can be separated from the bobbin in the material storage cavity through the second limiting block.

Preferably, a third sliding hole is formed in the pay-off frame in a penetrating mode, the third sliding hole is communicated with the material storage cavity, the third limiting mechanism comprises a third limiting block and a third driving cylinder, the third limiting block is connected in the third sliding hole in a sliding mode, and the third driving cylinder is used for driving the third limiting block to slide in the third sliding hole.

Through the technical scheme, when the third limiting mechanism is used for limiting the bobbin, the third limiting block is controlled to move towards the material storage cavity through the third driving cylinder until the third limiting block protrudes out of the inner wall of the material storage cavity, and the bobbin in the preparation section can be separated from the bobbin in the storage section by the third limiting block at the moment.

Drawings

FIG. 1 is a schematic structural diagram according to a first embodiment;

FIG. 2 is a schematic cross-sectional view of the first embodiment;

FIG. 3 is a logic block diagram of the first embodiment;

FIG. 4 is a schematic sectional view of the second embodiment;

FIG. 5 is an enlarged view of portion A of FIG. 4;

fig. 6 is a schematic structural diagram of the first stopper.

Reference numerals: 1. a pay-off frame; 2. a bobbin placing groove; 3. a bobbin positioning mechanism; 31. positioning a plate; 32. a movable tray; 33. a power member; 4. a servo motor; 5. a tension control mechanism; 6. a hysteresis clutch; 7. a movable executive component; 71. an actuating cylinder; 72. mounting a plate; 8. a housing; 9. a spool collection chamber; 10. an opening; 11. a rubber cushion pad; 12. a material storage chamber; 121. a preparation section; 122. a memory segment; 13. a first limit mechanism; 131. a first stopper; 132. a first driving cylinder; 14. a second limiting mechanism; 141. a second limiting block; 142. a second driving cylinder; 15. a third limiting mechanism; 151. a third limiting block; 152. a third driving cylinder; 16. a first sliding hole; 17. a first positioning groove; 18. a second sliding hole; 19. and a third sliding hole.

Detailed Description

The following detailed description of the embodiments of the present invention is provided in order to make the technical solution of the present invention easier to understand and understand.

The first embodiment is as follows:

the utility model provides a stranding machine with PLC constant tension control system, is including rotating unwrapping wire frame 1 of connection on the support, and carries out circumferential direction under the drive of unwrapping wire frame 1 accessible motor.

A plurality of line section of thick bamboo standing grooves 2 have been seted up on the surface of unwrapping wire frame 1, and each line section of thick bamboo standing groove 2 all sets up along the radial of unwrapping wire frame 1. The plurality of bobbin placing grooves 2 are evenly divided into a plurality of bobbin placing groups, and the plurality of bobbin placing groups are distributed at equal intervals along the circumferential direction of the pay-off frame 1. The plurality of bobbin placing grooves 2 in each bobbin placing group are equally spaced along the axial direction of the pay-off frame 1. When the wire winding device is used, a wire winding barrel wound with a wire core is placed in each wire winding barrel placing groove 2.

The paying-off frame 1 is provided with the bobbin positioning mechanism 3, the number of the bobbin positioning mechanism 3 is the same as that of the bobbin paying-off grooves, the bobbin positioning mechanism 3 and the bobbin placing grooves 2 are arranged in a one-to-one correspondence mode, the bobbin positioning mechanism 3 is used for positioning bobbins in the bobbin placing grooves 2, and therefore the bobbins can only rotate circumferentially in the bobbin placing grooves 2.

As shown in fig. 1 and 2, the bobbin positioning mechanism 3 includes a positioning plate 31, a movable plate 32, and a power member 33. The positioning plate 31 is arranged on the inner groove wall on one side of the bobbin placing groove 2, the positioning plate 31 can rotate circumferentially relative to the inner groove wall, and meanwhile, the positioning plate 31 can slide along the direction perpendicular to the inner groove wall. The pay-off frame 1 is provided with a movable executing member 7, and the movable executing member 7 includes an executing cylinder 71 and a mounting plate 72. An actuating cylinder 71 is mounted on the pay-off frame 1, and a piston rod of the actuating cylinder 71 is disposed on a side of the cylinder body of the actuating cylinder 71 facing the positioning plate 31. The mounting plate 72 is arranged at the end part of the piston rod of the actuating cylinder 71, the servo motor 4 is arranged at one side of the mounting plate 72 close to the positioning disc 31, the output shaft of the servo motor 4 is connected with the positioning disc 31, and the servo motor 4 is used for driving the positioning disc 31 to rotate in the circumferential direction when in use. The movable disc 32 is arranged on an inner groove wall of the bobbin placing groove 2, which is right opposite to the positioning disc 31, the movable disc 32 can rotate circumferentially relative to the inner groove wall, and meanwhile, the movable disc 32 can also slide along a direction vertical to the inner groove wall. The pay-off frame 1 is provided with a power member 33, and the power member 33 is used for driving the movable disc 32 to move along the direction vertical to the inner wall of the bobbin placing groove 2. The power member 33 may be a screw with a handle or a cylinder. When a screw with a handle is selected, the screw needs to be rotationally connected with the positioning disc 31, so that the screw is not easy to directly drive the movable disc 32 in the process of rotating the screw.

As shown in fig. 2 and 3, the strander with the PLC constant tension control system further includes a tension control mechanism 5, the tension control mechanism 5 includes a frequency converter, a tension detector, a rotary encoder, and a PLC controller, the tension detector detects tension of the wire core and transmits a signal to the PLC controller, the rotary encoder detects a paying-off speed of the wire drum and transmits a signal to the PLC controller, and the PLC controller processes the signal and controls a rotation speed of the servo motor 4 through the frequency converter.

As shown in fig. 1, the wire twisting machine having the PLC constant tension control system further includes a hysteresis clutch 6.

Example two:

as shown in fig. 4, the exterior of the pay-off frame 1 is covered with a cover 8, and the pay-off frame 1 rotates circumferentially in the cover 8 when in use. A spool collecting chamber 9 is formed between the outer cover 8 and the pay-off frame 1, and a spool in the spool collecting chamber 9 can move downwards along the inner wall of the outer cover 8. The bottom of the outer cover 8 is provided with an opening 10, and the bobbin moved to the bottom of the outer cover 8 can fall down from the opening 10, so that the bobbin can be conveniently collected by workers. The inner wall of the outer cover 8 is provided with a cushion rubber pad for protecting the outer cover 8, so that the outer cover 8 is not easy to deform.

As shown in fig. 4 and 5, the pay-off frame 1 is provided with material storage chambers 12 communicated with the bobbin placing grooves 2 one by one, the material storage chambers 12 are located on one side of the bobbin placing grooves 2 close to the central line of the pay-off frame 1, and the material storage chambers 12 are arranged along the radial direction of the pay-off frame 1.

As shown in fig. 4, 5, and 6, two sets of first limiting mechanisms 13 are disposed at the inner wall of the bobbin placing groove 2 away from the material storage chamber 12, the two sets of first limiting mechanisms 13 are symmetrically distributed at two sides of the bobbin placing groove 2, and the two sets of first limiting mechanisms 13 are matched to limit the bobbins in the bobbin placing groove 2 from entering the bobbin collecting chamber 9. The opposite position of the pay-off frame 1 and the first limiting mechanism 13 is provided with a first sliding hole 16 in a penetrating manner, and the first sliding hole 16 is arranged along the direction vertical to the inner groove wall of the first limiting mechanism 13. The first stopper mechanism 13 includes a first stopper 131 and a first driving cylinder 132. The first limiting block 131 is connected in the first sliding hole 16 in a sliding manner, and a first positioning groove 17 is formed in one side of the first limiting block 131 facing the material storage chamber 12. The first driving cylinder 132 is installed on the pay-off frame 1, and a piston rod of the first driving cylinder 132 is connected with the first stopper 131.

Two groups of second limiting mechanisms 14 are arranged at the joint of the bobbin placing groove 2 and the material storage cavity 12, the two groups of second limiting mechanisms are symmetrically distributed on two sides of the joint, and the two groups of second limiting mechanisms 14 are used for limiting bobbins in the material storage cavity 12 to enter the bobbin placing groove 2. The pay-off frame 1 is provided with a second sliding hole 18 in a penetrating manner, and the second sliding hole 18 is arranged along a direction perpendicular to the joint. The second stopper mechanism 14 includes a second stopper 141 and a second driving cylinder 142. The second stopper 141 is slidably coupled to the second sliding hole 18. The second driving cylinder 142 is installed on the pay-off frame 1, and a piston rod of the second driving cylinder 142 is connected to the second stopper 141.

Two sets of third stop gear 15 are provided with in the inner wall department of material stock cavity 12, two sets of third stop gear 15 symmetric distribution are in the both sides of material stock cavity 12, two sets of third stop gear 15 divide material stock cavity 12 into prepare section 121 and the memory segment 122 of keeping away from line section of thick bamboo standing groove 2 near line section of thick bamboo standing groove 2, only can deposit a line section of thick bamboo in preparing section 121, can deposit a plurality of line sections of thick bamboo in the memory segment 122, two sets of third stop gear 15 cooperate and are used for restricting the line section of thick bamboo in the memory segment 122 and enter into and prepare in the section 121. A third sliding hole 19 is formed in the pay-off frame 1 in a penetrating mode, the third sliding hole 19 is arranged in the direction perpendicular to the inner side wall where the third limiting mechanism 15 is located, and the third sliding hole 19 is communicated with the material storage chamber 12. The third limiting mechanism 15 includes a third limiting block 151 and a third driving cylinder 152, the third limiting block 151 is slidably connected to the third sliding hole 19, and a piston rod of the third driving cylinder 152 is connected to the third limiting block 151.

The above are only typical examples of the present invention, and besides, the present invention may have other embodiments, and all the technical solutions formed by equivalent substitutions or equivalent changes are within the scope of the present invention as claimed.

Claims

1. The utility model provides a stranding machine with PLC constant tension control system which characterized by: the paying-off device comprises a paying-off frame (1), wherein a bobbin placing groove (2) is formed in the surface of the paying-off frame (1), and a bobbin wound with a wire core is placed in the bobbin placing groove (2);

the paying-off frame (1) is provided with a bobbin positioning mechanism (3), and the bobbin positioning mechanism (3) is used for positioning bobbins in the bobbin placing groove (2); the bobbin positioning mechanism (3) comprises a positioning disc (31), a movable disc (32) and a power part (33), the positioning disc (31) is rotatably connected to the inner groove wall of the bobbin placing groove (2), the movable disc (32) is rotatably connected to the inner groove wall, opposite to the positioning disc (31), of the bobbin placing groove (2), and the power part (33) is used for driving the movable disc (32) to move along the axial direction of the power part;

the pay-off frame (1) is provided with a servo motor (4), and the servo motor (4) is used for driving the positioning disc (31) to rotate in the circumferential direction; still include tension control mechanism (5), tension control mechanism (5) include converter, tension detector, rotary encoder, PLC controller, and tension detector detects the tension of sinle silk and transmits the signal to the PLC controller, rotary encoder detects the unwrapping wire speed of a line section of thick bamboo and transmits the signal to the PLC controller, and the PLC controller passes through the converter control the rotational speed of servo motor (4).

2. The stranding machine having a PLC constant tension control system of claim 1 wherein: also comprises a hysteresis clutch (6) mounted on the pay-off frame (1).

3. The stranding machine having a PLC constant tension control system of claim 1 wherein: be provided with movable executive (7) on unwrapping wire frame (1), movable executive (7) are in including actuating cylinder (71), setting actuating cylinder (71) piston rod on mounting panel (72), servo motor (4) are installed on mounting panel (72), movable executive (7) are used for the drive servo motor (4) and positioning disk (31) move along the axial machine of positioning disk (31).

4. The stranding machine having a PLC constant tension control system of claim 1 wherein: still establish including the cover (8) outside the unwrapping wire frame (1), cover (8) with be formed with line section of thick bamboo collection chamber (9) between unwrapping wire frame (1), opening (10) have been seted up to the bottom of cover (8), opening (10) communicate in line section of thick bamboo collection chamber (9).

5. The stranding machine having a PLC constant tension control system of claim 4 wherein: and a rubber buffer pad (11) is arranged on the inner wall of the outer cover (8).

6. The stranding machine having a PLC constant tension control system of claim 4 wherein: a material storage chamber (12) is formed in the pay-off frame (1), the material storage chamber (12) is positioned on one side, close to the central line of the pay-off frame (1), of the bobbin placing groove (2), and the material storage chamber (12) is communicated with the bobbin placing groove (2);

two groups of first limiting mechanisms (13) are symmetrically arranged on the inner groove wall of the bobbin placing groove (2) far away from the material storage cavity (12), and the two groups of first limiting mechanisms (13) are matched to limit bobbins in the bobbin placing groove (2) from entering the bobbin collecting cavity (9);

two groups of second limiting mechanisms (14) are symmetrically arranged at the joint of the bobbin placing groove (2) and the storage cavity (12), and the two groups of second limiting mechanisms (14) are used for limiting bobbins in the storage cavity (12) from entering the bobbin placing groove (2);

two groups of third limiting mechanisms (15) are symmetrically arranged on the inner wall of the stock chamber (12), the stock chamber (12) is divided into a preparation section (121) close to the bobbin placing groove (2) and a storage section (122) far away from the bobbin placing groove (2) by the two groups of third limiting mechanisms (15), and the two groups of third limiting mechanisms (15) are matched to limit bobbins in the storage section (122) from entering the preparation section (121).

7. The stranding machine having a PLC constant tension control system of claim 6 wherein: the pay-off frame (1) is provided with a first sliding hole (16) in a penetrating mode, the first limiting mechanism (13) comprises a first limiting block (131) and a first driving air cylinder (132), the first limiting block (131) is connected in the first sliding hole (16) in a sliding mode, one side, facing the material storage cavity (12), of the first limiting block (131) is provided with a first positioning groove (17), the first driving air cylinder (132) is installed on the pay-off frame (1), and the first driving air cylinder (132) is used for driving the first limiting block (131) to slide in the first sliding hole (16).

8. The stranding machine having a PLC constant tension control system of claim 6 wherein: the paying-off frame (1) is provided with a second sliding hole (18) in a penetrating mode, the second sliding hole (18) is communicated with the joint of the bobbin placing groove (2) and the material storage cavity (12), the second limiting mechanism (14) comprises a second limiting block (141) and a second driving air cylinder (142), the second limiting block (141) is connected in the second sliding hole (18) in a sliding mode, the second driving air cylinder (142) is installed on the paying-off frame (1), and the second driving air cylinder (142) is used for driving the second limiting block (141) to slide in the second sliding hole (18).

9. The stranding machine having a PLC constant tension control system of claim 6 wherein: the pay-off frame (1) is provided with a third sliding hole (19) in a penetrating mode, the third sliding hole (19) is communicated with the material storage cavity (12), the third limiting mechanism (15) comprises a third limiting block (151) and a third driving cylinder (152), the third limiting block (151) is connected in the third sliding hole (19) in a sliding mode, and the third driving cylinder (152) is used for driving the third limiting block (151) to slide in the third sliding hole (19).