A four-roll centering roll-based opening degree adjusting method

Abstract

The application discloses a four-roll centering roller-based opening degree adjusting method, solves the problems that the rolled steel pipe is easy to fall along the vertical direction and the wall thickness and the ovality of the rolled steel pipe are out of tolerance, arranges one centering roller above, below, left and right of the rolling center line to form a four-roll centering arrangement mode, sets four centering pins on the frame around the rolling center, hingedly connects one special-shaped swing arm on each centering pin, connects the four special-shaped swing arms together through connecting rods to form three parallelogram four-link mechanisms which can be connected simultaneously, and makes the four centering rollers always arranged on a circle through the three parallelogram four-link mechanisms which can swing simultaneously, so that the synchronous adjustment of the opening degree is realized, and the four centering rollers are always arranged on the same circle.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of seamless steel tube production equipment in metallurgical industry, in particular to a kind of centering roller device for seamless steel tube production. BACKGROUND

[0002] In the seamless steel tube production equipment such as piercing mill and pipe mill, centering roller device is arranged; centering roller device plays the supporting role to the top rod or mandrel in rolling process, and also plays the guiding role to the steel pipe in rolling, to prevent the steel pipe in rolling from being scratched due to swing, and the ovality of the steel pipe being rolled from being out of tolerance; the existing centering roller device is generally three-roll centering roller, the centering axes of the three rollers are arranged at 120° angle to each other, and the three-roll centering roller is arranged on the same circumference, one of the rollers is arranged directly above the rolling line, and the other two rollers are arranged on the left and right sides of the rolling line; the positions of the three rollers are controlled by hydraulic cylinder to adjust the size of the opening, and the opening and closing of the roller above the rolling line is controlled by another hydraulic cylinder to realize the discharge of the steel pipe; the arrangement of the three-roll centering roller device has the following problems: (1) lacking supporting rollers in the vertical direction below the rolling line, the steel pipe being rolled is easy to fall along the vertical direction, causing damage and clamping of the steel pipe; (2) when adjusting the opening of the three-roll centering roller, the centering center is easy to deviate, causing the wall thickness and ovality of the steel pipe after rolling to be out of tolerance. SUMMARY

[0003] The present application provides an opening adjustment method based on four-roll centering roller, which solves the above-mentioned defects of the existing three-roll centering roller device in the arrangement of centering roller.

[0004] The present application solves the above technical problems by the following technical solutions:

[0005] The general idea of the present application is: arranging a centering roller above, below, left and right of the rolling center line to form a four-roll centering arrangement; arranging four centering pins on the frame around the rolling center, hinging a special-shaped swing arm on each centering pin, and connecting the four special-shaped swing arms together through connecting rods to form three parallelogram four-link mechanisms that can be connected simultaneously, and through the three parallelogram four-link mechanisms that can swing simultaneously, the four centering rollers are always arranged on a circumference, and the three parallelogram four-link mechanisms are controlled by the same electric control oil cylinder to realize synchronous swinging, thereby realizing synchronous adjustment of the opening, and ensuring that the four centering rollers are always on the circumference of the same circle, and the centers of these circles are always coincident with the rolling center line.

[0006] The utility model provides a four roll centering roller device, including frame, be centered steel pipe, open degree adjustment electric control hydraulic cylinder, discharge opening open and close control hydraulic cylinder, upper centering roller, right centering roller, lower centering roller and left centering roller, be provided with the rolling center line in the frame, be provided with the right upper centering pin shaft on the frame right upper of the rolling center line, be provided with the right lower centering pin shaft on the frame right lower of the rolling center line, be provided with the left lower centering pin shaft on the frame left lower of the rolling center line, be provided with the left upper centering pin shaft on the frame left upper of the rolling center line, the V -shaped swing arm is hinged on the right upper centering pin shaft, and the middle part of V -shaped swing arm is hinged on the right upper centering pin shaft, and the upper centering roller is provided with on the left end of V -shaped swing arm, and the first connecting pin shaft is provided with on the right end of V -shaped swing arm, the W -shaped swing arm is hinged on the right lower centering pin shaft, and the left lower end of W -shaped swing arm is hinged on the right lower centering pin shaft, and the right centering roller is provided with on the left upper end of W -shaped swing arm, and the second connecting pin shaft is provided with on the middle top of W -shaped swing arm, and the third connecting pin shaft is provided with on the right upper end of W -shaped swing arm, and the fourth connecting pin shaft is provided with on the right lower end of W -shaped swing arm, the Y -shaped swing arm is hinged on the left lower centering pin shaft, and the middle part of Y -shaped swing arm is hinged on the left lower centering pin shaft, and the lower centering roller is provided with on the right upper end of Y -shaped swing arm, and the fifth connecting pin shaft is provided with on the lower end of Y -shaped swing arm, and the sixth connecting pin shaft is provided with on the left upper end of Y -shaped swing arm, and the inverted V -shaped swing arm is hinged on the left upper centering pin shaft, and the middle part of inverted V -shaped swing arm is hinged on the left upper centering pin shaft, and the left centering roller is provided with on the right end of inverted V -shaped swing arm, and the seventh connecting pin shaft is provided with on the left end of inverted V -shaped swing arm, the discharge opening open and close control hydraulic cylinder is connected between the first connecting pin shaft and the third connecting pin shaft, the open degree adjustment electric control hydraulic cylinder is fixedly arranged on the right middle part of frame, and the top end of the output shaft of open degree adjustment electric control hydraulic cylinder is hinged together with the second connecting pin shaft, the first connecting rod is connected between the fourth connecting pin shaft and the fifth connecting pin shaft, and the second connecting rod is connected between the sixth connecting pin shaft and the seventh connecting pin shaft, the upper centering roller, the right centering roller, the lower centering roller and the left centering roller are arranged on the circumference of the same circle, and the center of the circle is coincident with the rolling center line.

[0007] The right upper centering pin shaft, the first connecting pin shaft, the third connecting pin shaft and the right lower centering pin shaft are sequentially connected to form a right side four-link parallelogram, and the right upper centering pin shaft, the first connecting pin shaft, the third connecting pin shaft and the right lower centering pin shaft are four vertices of the right side four-link parallelogram; the right lower centering pin shaft, the fourth connecting pin shaft, the fifth connecting pin shaft and the left lower centering pin shaft are sequentially connected to form a lower four-link parallelogram, and the right lower centering pin shaft, the fourth connecting pin shaft, the fifth connecting pin shaft and the left lower centering pin shaft are four vertices of the lower four-link parallelogram; the left lower centering pin shaft, the left upper centering pin shaft, the seventh connecting pin shaft and the sixth connecting pin shaft are sequentially connected to form a left side four-link parallelogram, and the left lower centering pin shaft, the left upper centering pin shaft, the seventh connecting pin shaft and the sixth connecting pin shaft are four vertices of the left side four-link parallelogram.

[0008] An opening degree adjusting method based on a four-roll centering roll, if the centering steel pipe is relatively thin, the centering opening degree needs to be adjusted small:

[0009] The output shaft of the electric control hydraulic cylinder for adjusting the opening degree is controlled to stretch out to the left, and the stretched output shaft drives the W-shaped swing arm through the second connecting pin shaft, the W-shaped swing arm swings counterclockwise around the right lower centering pin shaft, and the right centering roll approaches the rolling center line;

[0010] At the same time that the W-shaped swing arm swings counterclockwise, the W-shaped swing arm drives the V-shaped swing arm through the discharge opening opening and closing control hydraulic cylinder and the first connecting pin shaft, the V-shaped swing arm also swings counterclockwise around the right upper centering pin shaft, and the upper centering roll approaches the rolling center line;

[0011] At the same time that the W-shaped swing arm swings counterclockwise, the fourth connecting pin shaft at the right lower part of the W-shaped swing arm drives the Y-shaped swing arm to rotate counterclockwise around the left lower centering pin shaft through the first connecting rod and the fifth connecting pin shaft, so that the lower centering roll approaches the rolling center line;

[0012] In the process that the Y-shaped swing arm rotates counterclockwise, the left lower end of the Y-shaped swing arm drives the inverted V-shaped swing arm through the sixth connecting pin shaft and the second connecting rod, the inverted V-shaped swing arm also rotates counterclockwise around the left upper centering pin shaft, and the left centering roll approaches the rolling center line;

[0013] Thus, the upper centering roll, the right centering roll, the lower centering roll and the left centering roll approach the rolling center line synchronously, and the purpose of adjusting the centering opening degree small is achieved.

[0014] If the centering steel pipe is relatively thick, the centering opening degree needs to be adjusted large:

[0015] The output shaft of the electric control hydraulic cylinder for adjusting the opening degree is controlled to retract to the right, and the retracted output shaft pulls the W-shaped swing arm through the second connecting pin shaft, the W-shaped swing arm swings clockwise around the right lower centering pin shaft, and the right centering roll moves away from the rolling center line;

[0016] When the W-shaped swing arm swings clockwise, the W-shaped swing arm pulls the V-shaped swing arm through the discharge opening opening and closing control hydraulic cylinder and the first connecting pin shaft, and the V-shaped swing arm also swings clockwise around the right upper centering pin shaft, so that the upper centering roller moves away from the rolling center line;

[0017] When the W-shaped swing arm swings clockwise, the fourth connecting pin shaft at the lower right of the W-shaped swing arm makes the Y-shaped swing arm rotate clockwise around the lower left centering pin shaft through the first connecting rod and the fifth connecting pin shaft, so that the lower centering roller moves away from the rolling center line;

[0018] During the clockwise rotation of the Y-shaped swing arm, the left lower end of the Y-shaped swing arm pulls the inverted V-shaped swing arm through the sixth connecting pin shaft and the second connecting rod, and the inverted V-shaped swing arm also rotates clockwise around the left upper centering pin shaft, so that the left centering roller moves away from the rolling center line;

[0019] Thus, the upper centering roller, the right centering roller, the lower centering roller and the left centering roller are simultaneously moved away from the rolling center line, achieving the purpose of increasing the opening degree.

[0020] If the centered steel pipe is moved away from the rolling center line:

[0021] By controlling the discharge opening opening and closing control hydraulic cylinder, the extended shaft passes through the first connecting pin shaft to drive the V-shaped swing arm to swing, and the V-shaped swing arm swings clockwise around the right upper centering pin shaft, so that the centering roller moves away from the upper side of the rolling center line, providing an upward passage for the movement of the centered steel pipe.

[0022] The present application has the advantages of simple structure, vertical roller support on the lower side of the rolling line, effective avoidance of the steel pipe from falling in the vertical direction, and the centering center not being offset at all after the opening degree is adjusted. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the present application;

[0024] Figure 2 is a structural schematic diagram of the V-shaped swing arm 14 of the present application;

[0025] Figure 3 is a structural schematic diagram of the W-shaped swing arm 16 of the present application;

[0026] Figure 4 is a structural schematic diagram of the Y-shaped swing arm 20 of the present application;

[0027] Figure 5 is a structural schematic diagram of the inverted V-shaped swing arm 23 of the present application. DETAILED DESCRIPTION

[0028] The present application will be described in detail below with reference to the drawings.

[0029] The utility model provides a four roll centering roll device, including frame 1, be centered steel pipe 2, open degree adjustment electric control hydraulic cylinder 3, discharge opening open and close control hydraulic cylinder 4, upper centering roll 5, right centering roll 6, lower centering roll 7 and left centering roll 8 are arranged with the rolling center line 13 in frame 1, the right upper centering pin shaft 9 is arranged on the frame 1 right upper of rolling center line 13, the right lower centering pin shaft 10 is arranged on the frame 1 right lower of rolling center line 13, the left lower centering pin shaft 11 is arranged on the frame 1 left lower of rolling center line 13, the left upper centering pin shaft 12 is arranged on the frame 1 left upper of rolling center line 13, the V-shaped swing arm 14 is hinged on the right upper centering pin shaft 9, the middle part of V-shaped swing arm 14 is hinged on the right upper centering pin shaft 9, the upper centering roll 5 is arranged on the left end of V-shaped swing arm 14, the first connecting pin shaft 15 is arranged on the right end of V-shaped swing arm 14, the W-shaped swing arm 16 is hinged on the right lower centering pin shaft 10, the left lower end of W-shaped swing arm 16 is hinged on the right lower centering pin shaft 10, the right centering roll 6 is arranged on the left upper end of W-shaped swing arm 16, the second connecting pin shaft 17 is arranged on the middle top end of W-shaped swing arm 16, the third connecting pin shaft 18 is arranged on the right upper end of W-shaped swing arm 16, the fourth connecting pin shaft 19 is arranged on the right lower end of W-shaped swing arm 16, the Y-shaped swing arm 20 is hinged on the left lower centering pin shaft 11, the middle part of Y-shaped swing arm 20 is hinged on the left lower centering pin shaft 11, the lower centering roll 7 is arranged on the right upper end of Y-shaped swing arm 20, the fifth connecting pin shaft 21 is arranged on the lower end of Y-shaped swing arm 20, the sixth connecting pin shaft 22 is arranged on the left upper end of Y-shaped swing arm 20, the inverted V-shaped swing arm 23 is hinged on the left upper centering pin shaft 12, the middle part of inverted V-shaped swing arm 23 is hinged on the left upper centering pin shaft 12, the left centering roll 8 is arranged on the right end of inverted V-shaped swing arm 23, the seventh connecting pin shaft 24 is arranged on the left end of inverted V-shaped swing arm 23, the discharge opening open and close control hydraulic cylinder 4 is connected between the first connecting pin shaft 15 and the third connecting pin shaft 18, the open degree adjustment electric control hydraulic cylinder 3 is fixedly arranged on the right middle part of frame 1, the top end of the output shaft of open degree adjustment electric control hydraulic cylinder 3 is hinged with the second connecting pin shaft 17, the first connecting rod 25 is connected between the fourth connecting pin shaft 19 and the fifth connecting pin shaft 21, the second connecting rod 26 is connected between the sixth connecting pin shaft 22 and the seventh connecting pin shaft 24, the upper centering roll 5, the right centering roll 6, the lower centering roll 7 and the left centering roll 8 are arranged on the circumference of the same circle, and the center of the circle coincides with the rolling center line 13, the hinge pin shafts arranged in a square shape around the frame of the rolling center line 13 are respectively hinged with a special-shaped swing arm, and the four swing arms are hinged together through connecting rods, so that the synchronous connection of the four swing arms is realized, and the four centering rolls connected on the four swing arms are always arranged on the circumference of the same circle during adjustment, and the centers of the circles coincide with the rolling center line 13, that is, the circles where the four centering rolls are arranged are concentric circles during adjustment.

[0030] After the right upper centering pin shaft 9, the first connecting pin shaft 15, the third connecting pin shaft 18 and the right lower centering pin shaft 10 are sequentially connected, a right side four-link parallelogram is formed, and the right upper centering pin shaft 9, the first connecting pin shaft 15, the third connecting pin shaft 18 and the right lower centering pin shaft 10 are four vertices of the right side four-link parallelogram; after the right lower centering pin shaft 10, the fourth connecting pin shaft 19, the fifth connecting pin shaft 21 and the left lower centering pin shaft 11 are sequentially connected, a lower four-link parallelogram is formed, and the right lower centering pin shaft 10, the fourth connecting pin shaft 19, the fifth connecting pin shaft 21 and the left lower centering pin shaft 11 are four vertices of the lower four-link parallelogram; after the left lower centering pin shaft 11, the left upper centering pin shaft 12, the seventh connecting pin shaft 24 and the sixth connecting pin shaft 22 are sequentially connected, a left side four-link parallelogram is formed, and the left lower centering pin shaft 11, the left upper centering pin shaft 12, the seventh connecting pin shaft 24 and the sixth connecting pin shaft 22 are four vertices of the left side four-link parallelogram; the three parallelograms are connected with each other, synchronous adjustment of the four centering rollers is completed, adjustment of the centering opening degree is realized, and it is ensured that the opening center line is always in the coincident position.

[0031] The application relates to a four-roll centering roll-based opening degree adjusting method, which comprises a rack 1, a centering steel pipe 2, an electric control hydraulic cylinder 3 for opening degree adjustment, an outlet opening and closing control hydraulic cylinder 4, an upper centering roll 5, a right centering roll 6, a lower centering roll 7, a left centering roll 8, a rolling center line 13 arranged in the rack 1, a right upper centering pin shaft 9 arranged on the upper right side of the rolling center line 13 of the rack 1, a right lower centering pin shaft 10 arranged on the lower right side of the rolling center line 13 of the rack 1, a left lower centering pin shaft 11 arranged on the lower left side of the rolling center line 13 of the rack 1, and a left upper centering pin shaft 12 arranged on the upper left side of the rolling center line 13 of the rack 1; a V-shaped swing arm 14 is hinged to the right upper centering pin shaft 9, the middle part of the V-shaped swing arm 14 is hinged to the right upper centering pin shaft 9, the upper centering roll 5 is arranged at the left end of the V-shaped swing arm 14, and a first connecting pin shaft 15 is arranged at the right end of the V-shaped swing arm 14; a W-shaped swing arm 16 is hinged to the right lower centering pin shaft 10, the left lower end of the W-shaped swing arm 16 is hinged to the right lower centering pin shaft 10, the right centering roll 6 is arranged at the left upper end of the W-shaped swing arm 16, a second connecting pin shaft 17 is arranged at the middle top end of the W-shaped swing arm 16, a third connecting pin shaft 18 is arranged at the right upper end of the W-shaped swing arm 16, and a fourth connecting pin shaft 19 is arranged at the right lower end of the W-shaped swing arm 16; a Y-shaped swing arm 20 is hinged to the left lower centering pin shaft 11, the middle part of the Y-shaped swing arm 20 is hinged to the left lower centering pin shaft 11, the lower centering roll 7 is arranged at the right upper end of the Y-shaped swing arm 20, a fifth connecting pin shaft 21 is arranged at the lower end of the Y-shaped swing arm 20, and a sixth connecting pin shaft 22 is arranged at the left upper end of the Y-shaped swing arm 20; an inverted V-shaped swing arm 23 is hinged to the left upper centering pin shaft 12, the middle part of the inverted V-shaped swing arm 23 is hinged to the left upper centering pin shaft 12, the left centering roll 8 is arranged at the right end of the inverted V-shaped swing arm 23, and a seventh connecting pin shaft 24 is arranged at the left end of the inverted V-shaped swing arm 23; the outlet opening and closing control hydraulic cylinder 4 is connected between the first connecting pin shaft 15 and the third connecting pin shaft 18, the electric control hydraulic cylinder 3 for opening degree adjustment is fixedly arranged at the middle part of the right side of the rack 1, the top end of the output shaft of the electric control hydraulic cylinder 3 for opening degree adjustment is hinged to the second connecting pin shaft 17, the first connecting rod 25 is connected between the fourth connecting pin shaft 19 and the fifth connecting pin shaft 21, and the second connecting rod 26 is connected between the sixth connecting pin shaft 22 and the seventh connecting pin shaft 24; the method is characterized in that,

[0032] If the centering steel pipe 2 is relatively thin and the centering opening degree needs to be adjusted,

[0033] the electric control hydraulic cylinder 3 for opening degree adjustment is controlled so that the output shaft thereof extends to the left, the extended output shaft pushes the W-shaped swing arm 16 through the second connecting pin shaft 17, the W-shaped swing arm 16 swings counterclockwise around the right lower centering pin shaft 10, and the right centering roll 6 approaches the rolling center line 13,

[0034] When the W-shaped swing arm 16 swings counterclockwise, the W-shaped swing arm 16 pushes the V-shaped swing arm 14 through the discharge opening opening and closing control hydraulic cylinder 4 and the first connecting pin shaft 15, and the V-shaped swing arm 14 also swings counterclockwise around the right upper centering pin shaft 9, so that the upper centering roller 5 approaches the rolling center line 13;

[0035] When the W-shaped swing arm 16 swings counterclockwise, the fourth connecting pin shaft 19 at the right lower part of the W-shaped swing arm 16 makes the Y-shaped swing arm 20 rotate counterclockwise around the left lower centering pin shaft 11 through the first connecting rod 25 and the fifth connecting pin shaft 21, so that the lower centering roller 7 approaches the rolling center line 13;

[0036] In the process of counterclockwise rotation of the Y-shaped swing arm 20, the left lower end of the Y-shaped swing arm 20 pushes the inverted V-shaped swing arm 23 through the sixth connecting pin shaft 22 and the second connecting rod 26, and the inverted V-shaped swing arm 23 also rotates counterclockwise around the left upper centering pin shaft 12, so that the left centering roller 8 approaches the rolling center line 13;

[0037] Thus, the upper centering roller 5, the right centering roller 6, the lower centering roller 7 and the left centering roller 8 are simultaneously close to the rolling center line 13, and the purpose of reducing the centering opening is achieved; the four special-shaped swing arms swing around the respective hinge pin shafts to realize the adjustment of the opening size, and in the adjustment process, the four centering rollers are always on the circumference of a concentric circle.

[0038] If the centered steel pipe 2 is relatively thick, and the centering opening needs to be increased:

[0039] The output shaft of the opening size adjustment control electro-hydraulic cylinder 3 is retracted to the right, and the retracted output shaft pulls the W-shaped swing arm 16 through the second connecting pin shaft 17, and the W-shaped swing arm 16 swings clockwise around the right lower centering pin shaft 10, so that the right centering roller 6 moves away from the rolling center line 13;

[0040] When the W-shaped swing arm 16 swings clockwise, the W-shaped swing arm 16 pulls the V-shaped swing arm 14 through the discharge opening opening and closing control hydraulic cylinder 4 and the first connecting pin shaft 15, and the V-shaped swing arm 14 also swings clockwise around the right upper centering pin shaft 9, so that the upper centering roller 5 moves away from the rolling center line 13;

[0041] When the W-shaped swing arm 16 swings clockwise, the fourth connecting pin shaft 19 at the right lower part of the W-shaped swing arm 16 makes the Y-shaped swing arm 20 rotate clockwise around the left lower centering pin shaft 11 through the first connecting rod 25 and the fifth connecting pin shaft 21, so that the lower centering roller 7 moves away from the rolling center line 13;

[0042] In the process of clockwise rotation of the Y-shaped swing arm 20, the left lower end of the Y-shaped swing arm 20 pulls the inverted V-shaped swing arm 23 through the sixth connecting pin shaft 22 and the second connecting rod 26, and the inverted V-shaped swing arm 23 also rotates clockwise around the left upper centering pin shaft 12, so that the left centering roller 8 moves away from the rolling center line 13;

[0043] Thus, the upper centering roller 5, the right centering roller 6, the lower centering roller 7 and the left centering roller 8 are realized to be synchronously away from the rolling center line 13, and the purpose of increasing the opening is achieved.

[0044] If the centered steel pipe 2 is moved away from the rolling center line:

[0045] By controlling the discharging opening opening and closing control hydraulic cylinder 4, the extending shaft passes through the first connecting pin shaft 15, drives the V-shaped swing arm 14 to swing, the V-shaped swing arm 14 swings clockwise around the right upper centering pin shaft 9, and the centering roller 5 is away from the directly above of the rolling center line 13, which provides an upward channel for the moving out of the centered steel pipe 2; the discharging opening opening and closing control hydraulic cylinder 4 plays the role of a connecting rod, and can also control the swing of the V-shaped swing arm 14 alone, realizes the moving away of the centering roller 5 above the rolling center line 13, and makes the centered steel pipe 2 move upward.

Claims

1. A four-roll centering roll-based opening degree adjustment method, comprising a rack (1), a centered steel pipe (2), an electrically-controlled hydraulic cylinder for opening degree adjustment (3), an outlet opening and closing control hydraulic cylinder (4), an upper centering roll (5), a right centering roll (6), a lower centering roll (7) and a left centering roll (8), a rolling center line (13) is arranged in the rack (1), a right upper centering pin shaft (9) is arranged on the upper right of the rolling center line (13) of the rack (1), a right lower centering pin shaft (10) is arranged on the lower right of the rolling center line (13) of the rack (1), a left lower centering pin shaft (11) is arranged on the lower left of the rolling center line (13) of the rack (1), and a left upper centering pin shaft (12) is arranged on the upper left of the rolling center line (13) of the rack (1); a V-shaped swing arm (14) is hinged to the right upper centering pin shaft (9), the middle part of the V-shaped swing arm (14) is hinged to the right upper centering pin shaft (9), the upper centering roll (5) is arranged at the left end of the V-shaped swing arm (14), and a first connecting pin shaft (15) is arranged at the right end of the V-shaped swing arm (14); a W-shaped swing arm (16) is hinged to the right lower centering pin shaft (10), the left lower end of the W-shaped swing arm (16) is hinged to the right lower centering pin shaft (10), the right centering roll (6) is arranged at the left upper end of the W-shaped swing arm (16), a second connecting pin shaft (17) is arranged at the middle top end of the W-shaped swing arm (16), a third connecting pin shaft (18) is arranged at the right upper end of the W-shaped swing arm (16), and a fourth connecting pin shaft (19) is arranged at the right lower end of the W-shaped swing arm (16); a Y-shaped swing arm (20) is hinged to the left lower centering pin shaft (11), the middle part of the Y-shaped swing arm (20) is hinged to the left lower centering pin shaft (11), the lower centering roll (7) is arranged at the right upper end of the Y-shaped swing arm (20), a fifth connecting pin shaft (21) is arranged at the lower end of the Y-shaped swing arm (20), and a sixth connecting pin shaft (22) is arranged at the left upper end of the Y-shaped swing arm (20); an inverted V-shaped swing arm (23) is hinged to the left upper centering pin shaft (12), the middle part of the inverted V-shaped swing arm (23) is hinged to the left upper centering pin shaft (12), the left centering roll (8) is arranged at the right end of the inverted V-shaped swing arm (23), and a seventh connecting pin shaft (24) is arranged at the left end of the inverted V-shaped swing arm (23); the outlet opening and closing control hydraulic cylinder (4) is connected between the first connecting pin shaft (15) and the third connecting pin shaft (18), the electrically-controlled hydraulic cylinder for opening degree adjustment (3) is fixedly arranged at the middle part of the right side of the rack (1), the top end of the output shaft of the electrically-controlled hydraulic cylinder for opening degree adjustment (3) is hinged to the second connecting pin shaft (17), the first connecting rod (25) is connected between the fourth connecting pin shaft (19) and the fifth connecting pin shaft (21), and the second connecting rod (26) is connected between the sixth connecting pin shaft (22) and the seventh connecting pin shaft (24); characterized in that, if the centered steel pipe (2) is relatively thin and the centering opening degree needs to be adjusted to be small: ​ Control the opening degree adjustment with electric control hydraulic cylinder (3), make its output shaft to left stretch out, the output shaft that stretches out pushes W type swing arm (16) through second connecting pin shaft (17), W type swing arm (16) around right lower centering pin shaft (10) counterclockwise swing, make right centering roller (6) close to rolling center line (13); While W type swing arm (16) counterclockwise swing, W type swing arm (16) through the discharge opening open and close control hydraulic cylinder (4) and first connecting pin shaft (15), push V type swing arm (14), V type swing arm (14) also counterclockwise swing around right upper centering pin shaft (9), make upper centering roller (5) close to rolling center line (13); While W type swing arm (16) counterclockwise swing, W type swing arm (16) right lower part fourth connecting pin shaft (19), through first connecting rod (25) and fifth connecting pin shaft (21), make Y type swing arm (20) counterclockwise rotate around left lower centering pin shaft (11), make lower centering roller (7) close to rolling center line (13); In the process of Y type swing arm (20) counterclockwise rotation, the left lower end of Y type swing arm (20) pushes inverted V type swing arm (23) through sixth connecting pin shaft (22) and second connecting rod (26), inverted V type swing arm (23) also counterclockwise rotate around left upper centering pin shaft (12), make left centering roller (8) close to rolling center line (13); Thus realized upper centering roller (5), right centering roller (6), lower centering roller (7) and left centering roller (8), synchronous close to rolling center line (13), reached the purpose of small centering opening degree.

2. The method of opening adjustment based on four centered rolls according to claim 1, characterized in that, After connecting the right upper centering pin shaft (9), the first connecting pin shaft (15), the third connecting pin shaft (18) and the right lower centering pin shaft (10) in sequence with straight lines, a right side four-bar linkage parallelogram is formed; after connecting the right lower centering pin shaft (10), the fourth connecting pin shaft (19), the fifth connecting pin shaft (21) and the left lower centering pin shaft (11) in sequence with straight lines, a lower four-bar linkage parallelogram is formed; after connecting the left lower centering pin shaft (11), the left upper centering pin shaft (12), the seventh connecting pin shaft (24) and the sixth connecting pin shaft (22) in sequence with straight lines, a left side four-bar linkage parallelogram is formed; the upper centering roller (5), the right centering roller (6), the lower centering roller (7) and the left centering roller (8) are arranged on the circumference of the same circle, and the center of the same circle coincides with the rolling center line (13).

3. The opening degree adjusting method based on the four-roll centering roller according to claim 1, characterized in that, if the centered steel pipe (2) is relatively thick and the centering opening degree needs to be adjusted to be larger: control the opening degree adjustment with electric control hydraulic cylinder (3), make its output shaft to right retract, retract the output shaft through second connecting pin shaft (17) pull W type swing arm (16), W type swing arm (16) around right lower centering pin shaft (10) clockwise swing, make right centering roller (6) away from rolling center line (13); When the W-shaped swing arm (16) swings clockwise, the W-shaped swing arm (16) pulls the V-shaped swing arm (14) through the discharge opening opening and closing control hydraulic cylinder (4) and the first connecting pin shaft (15), and the V-shaped swing arm (14) also swings clockwise around the right upper centering pin shaft (9), so that the upper centering roller (5) moves away from the rolling center line (13); When the W-shaped swing arm (16) swings clockwise, the fourth connecting pin shaft (19) at the right lower part of the W-shaped swing arm (16) rotates the Y-shaped swing arm (20) clockwise around the left lower centering pin shaft (11) through the first connecting rod (25) and the fifth connecting pin shaft (21), so that the lower centering roller (7) moves away from the rolling center line (13); During the clockwise rotation of the Y-shaped swing arm (20), the left lower end of the Y-shaped swing arm (20) pulls the inverted V-shaped swing arm (23) through the sixth connecting pin shaft (22) and the second connecting rod (26), and the inverted V-shaped swing arm (23) also rotates clockwise around the left upper centering pin shaft (12), so that the left centering roller (8) moves away from the rolling center line (13); Thus, the upper centering roller (5), the right centering roller (6), the lower centering roller (7) and the left centering roller (8) are simultaneously moved away from the rolling center line (13), achieving the purpose of increasing the opening degree.

4. The gauge adjustment method based on four centering rolls according to claim 1 or 2 or 3, characterized in that, If the centered steel pipe (2) is moved away from the rolling center line: By controlling the discharge opening opening and closing control hydraulic cylinder (4), the shaft is extended through the first connecting pin shaft (15) to drive the V-shaped swing arm (14) to swing, and the V-shaped swing arm (14) swings clockwise around the right upper centering pin shaft (9), so that the centering roller (5) is away from the upper of the rolling center line (13), providing an upward passage for the movement of the centered steel pipe (2).

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