A mandrel self-centering device for a cold pilger mill

Abstract

This application relates to the field of steel pipe manufacturing machinery, specifically disclosing a mandrel self-centering device for a cold-rolled tube mill. The device includes a frame with multiple feeding mechanisms spaced apart along the raw tube feeding direction. A mandrel support mechanism and a mandrel self-centering mechanism are provided between adjacent feeding mechanisms. A sensing mechanism for detecting the tube end's position is provided on the side of each feeding mechanism facing the raw tube feeding direction. Each feeding mechanism includes a roller box, two rotating seats rotatably connected to the roller box, a feed roller rotatably connected to the rotating seats, an avoidance drive assembly for driving the two rotating seats to rotate in opposite directions, and a feeding drive assembly for driving the feed roller to rotate. The axis of the feed roller is offset from the axis of rotation of the rotating seats. This application controls the spacing of the feed rollers by controlling the position of the raw tube, completely eliminating damage to the feed rollers from the raw tube and greatly protecting the surface quality of the raw tube.

Description

Technical Field

[0001] This application relates to the field of steel pipe manufacturing machinery, and in particular to a mandrel self-centering device for cold rolling mills. Background Technology

[0002] Cold rolling mills are common steel pipe manufacturing machines. They cold roll rough tubes through annular holes to form steel pipes of the required specifications. They have the advantages of high material utilization, high precision, and high degree of automation.

[0003] The mandrel is an important component of the cold rolling mill. It is used to insert the rough tube, providing necessary support and fixation to prevent deformation or collapse of the rough tube during rolling, and ensuring the stability and continuity of the rolling process.

[0004] In related technologies, the mandrel is clamped and centered by feed rollers. During the feeding process, the rough tube directly pushes the two feed rollers apart in an upward and downward direction, allowing the rough tube to fit into the mandrel. However, in this case, due to continuous feeding, the end of the rough tube will repeatedly impact the feed rollers, resulting in severe wear on the roller surface. Furthermore, the centering accuracy of the mandrel is not high, and sometimes the rough tube cannot fit into the mandrel, causing feeding failure. Summary of the Invention

[0005] In order to achieve continuous feeding and eliminate damage to the structure caused by the rough tube, this application provides a mandrel self-centering device for cold rolling mills.

[0006] The self-centering device for mandrels used in cold rolling mills provided in this application adopts the following technical solution: A mandrel self-centering device for a cold rolling mill includes a frame, on which a plurality of feeding mechanisms are spaced apart along the raw tube feeding direction. A mandrel support mechanism and a mandrel self-centering mechanism are provided between adjacent feeding mechanisms. A sensing mechanism for detecting the tube end position is provided on the side of the feeding mechanism facing the raw tube feeding direction. The feeding mechanism includes a roller box, two rotating seats rotatably connected to the roller box, a feeding roller rotatably connected to the rotating seats, an avoidance drive assembly for driving the two rotating seats to rotate in opposite directions, and a feeding drive assembly for driving the feeding roller to rotate. The axis of the feeding roller is offset from the axis of rotation of the rotating seat.

[0007] By adopting the above technical solution, in the initial state, the avoidance drive component drives the two rotating seats to rotate in opposite directions, which increases the distance of the feeding rollers, so that the rough tube can pass through, eliminates the damage caused by the rough tube to the structure, and realizes continuous feeding.

[0008] When the raw tube passes the first sensing mechanism, a stroke calculation is triggered. When the calculation indicates that the end of the raw tube is about to pass the feed roller, the avoidance drive component drives the two rotating seats to rotate in opposite directions, causing the feed roller to clamp the raw tube. The feeding drive component then drives the feed roller to rotate, thus feeding the raw tube. When the raw tube passes the second sensing mechanism, the same action is triggered, achieving clamping and feeding of the raw tube.

[0009] Optionally, the avoidance drive assembly includes a drive component mounted on the roller box, a drive rack connected to the drive component, and a drive gear fixedly sleeved on the outside of the rotating seat. The two drive gears mesh with each other, and the drive rack meshes with one of the drive gears.

[0010] By adopting the above technical solution, the driving component drives the driving rack to move, which in turn drives the driving gear to rotate, causing the two rotating seats to rotate in opposite directions, thereby adjusting the spacing of the feeding rollers so that the rough pipe will not collide with the feeding rollers when passing through.

[0011] Optionally, a slide rail is connected to the inner side of the roller box, and the drive rack is slidably connected to the slide rail.

[0012] By adopting the above technical solution, guidance is provided for the sliding of the drive rack, ensuring the smooth operation of the transmission process.

[0013] Optionally, a partition is fixedly connected to the inner side of the roller box, and the end of the rotating seat away from the feed roller is rotatably connected to the partition.

[0014] By adopting the above technical solution, the rotating seat receives good support.

[0015] Optionally, the feeding drive assembly includes a drive motor mounted on one side of the roller box, a drive gear connected to the output shaft of the drive motor, a drive shaft passing through the inside of the rotating seat, a driven gear connected to one end of the drive shaft, a transmission gear connected to the other end of the drive shaft, a rotating shaft connected to the feed roller, and a rotating gear connected to the rotating shaft. The two driven gears mesh with each other, the drive gear meshes with one of the driven gears, and the transmission gear meshes with the rotating gear.

[0016] By adopting the above technical solution, the drive motor is started, which drives the active gear to rotate, causing the driven gear to rotate. The two drive shafts rotate in opposite directions, which in turn drives the transmission gear and the rotating gear to rotate, thereby realizing the rotation of the two feeding rollers and driving the raw tube to feed.

[0017] Optionally, a cover is rotatably connected to the end of the drive shaft away from the rotating seat, and the cover is fixedly connected to the side wall of the roller box opposite to the rotating seat. The rotating seat includes a hollow shaft through which the drive shaft passes, a seat body fixedly connected to the hollow shaft, and a cover body fixedly connected to the seat body. The transmission gear and the rotating gear are both located inside the seat body.

[0018] By adopting the above technical solution, the feeding drive component and the obstacle avoidance drive component are set independently and will not interfere with each other, ensuring smooth feeding of raw tubes.

[0019] Optionally, the core rod self-centering mechanism includes a mounting base connected to the frame, a slide plate vertically slidably connected to the mounting base, a lifting component for driving the slide plate to rise and fall, a lower centering wheel rotatably connected to the upper end of the slide plate, swing arms disposed on both sides of the lower centering wheel, and side centering wheels rotatably connected to the swing arms. Inclined surfaces are provided on both sides of the upper end of the slide plate. A rotating wheel that abuts against the inclined surface is connected to the lower end of the swing arm. A fixing component is connected to the lower end of the swing arm, and a tension spring is connected between the two fixing components.

[0020] By adopting the above technical solution, when the lifting component moves the slide plate downward, the lower centering wheel moves downward, and the lower ends of the two swing arms are brought closer to each other by the action of the tension spring. The two side centering wheels move in opposite directions, which increases the space between the lower centering wheel and the two side centering wheels, making it easier for the rough pipe to pass through.

[0021] Optionally, the mounting base includes a centering roller seat and a cover plate connected to the centering roller seat. The slide plate and the swing arm are both connected to the centering roller seat, and the centering roller seat is provided with a movable hole for the fixing member to pass through.

[0022] The above technical solution facilitates assembly.

[0023] Optionally, the core rod support mechanism includes a support connected to the frame, a core rod slot connected to the upper side of the support, and a nylon pad connected to the inner side of the core rod slot.

[0024] By adopting the above technical solution, the support effect of the core rod is good, and it can support long and heavy core rods.

[0025] Optionally, the sensing mechanism includes a support frame for the passage of the stubble, the support frame being connected to a sensor for detecting the position of the stubble.

[0026] In summary, this application has the following beneficial effects: 1. By using a self-centering three-point fixing method, the centering effect of the core rod is improved, so that the rough tube can be more accurately fitted into the core rod; 2. The spacing of the feeding rollers is adjusted by controlling the position of the raw tube to facilitate its passage, eliminate damage to the structure caused by the raw tube, achieve continuous feeding, and greatly protect the surface quality of the raw tube. 3. The mandrel self-centering mechanism and mandrel support mechanism can support long and heavy mandrels, reducing movement during the rolling process; 4. The structure of this application can be freely disassembled, making it convenient to replace and clean the parts. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the mandrel self-centering device for a cold rolling mill according to an embodiment of this application; Figure 2 This is a schematic diagram of the feeding mechanism and sensing mechanism according to an embodiment of this application; Figure 3 This is a schematic diagram of the feeding mechanism after removing the roller box according to an embodiment of this application; Figure 4 This is a top view schematic diagram of the feeding mechanism according to an embodiment of this application; Figure 5 yes Figure 4 Cross-sectional view along line AA; Figure 6 This is a front view schematic diagram of the feeding mechanism according to an embodiment of this application; Figure 7 yes Figure 6 Cross-sectional view along line BB; Figure 8 This is a schematic diagram of the core rod support mechanism and the core rod self-centering mechanism according to an embodiment of this application; Figure 9 This is an exploded view of the core rod self-centering mechanism according to an embodiment of this application; Figure 10 This is a schematic diagram of the self-centering mechanism of the core rod according to an embodiment of this application.

[0028] Explanation of reference numerals in the attached drawings: 1. Frame; 2. Feeding mechanism; 21. Roller box; 211. Slide rail; 212. Partition plate; 22. Rotating seat; 221. Hollow shaft; 222. Seat body; 223. Cover; 23. Feed roller; 24. Avoidance drive assembly; 241. Drive component; 242. Drive rack; 243. Drive gear; 25. Feeding drive assembly; 251. Drive motor; 252. Drive gear; 253. Drive shaft; 254. Driven gear; 255. Transmission gear; 256. Rotation. 1. Shaft; 257. Rotating gear; 258. End cap; 3. Core rod support mechanism; 31. Support; 32. Core rod slot; 33. Nylon pad; 4. Core rod self-centering mechanism; 41. Mounting seat; 411. Centering roller; 4111. Movable hole; 412. Cover plate; 42. Slide plate; 421. Inclined surface; 43. Lifting component; 44. Lower centering wheel; 45. Swing arm; 46. Side centering wheel; 47. Rotating wheel; 48. Fixing component; 49. Tension spring; 5. Sensing mechanism; 51. Support frame; 52. Sensor. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-10 This application will be described in further detail.

[0030] This application discloses a mandrel self-centering device for a cold rolling mill, used to achieve mandrel positioning and centering, so as to facilitate the insertion of raw tubes.

[0031] Reference Figure 1 A mandrel self-centering device for a cold rolling mill includes a frame 1, a feeding mechanism 2 for clamping and feeding the rough tube, a mandrel support mechanism 3 for supporting the mandrel, a mandrel self-centering mechanism 4 for positioning and centering the mandrel, and a sensing mechanism 5 for sensing whether the end of the rough tube is in position. The feeding mechanism 2 is mounted on the upper side of the frame 1, and four feeding mechanisms 2 are spaced apart along the feeding direction of the rough tube. In other embodiments, the number of feeding mechanisms 2 can be three, five, six, etc., depending on actual needs. Three mandrel support mechanisms 3 and three mandrel self-centering mechanisms 4 are provided, located between adjacent feeding mechanisms 2, with the mandrel support mechanism 3 located on the side of the corresponding mandrel self-centering mechanism 4 facing the feeding direction of the rough tube. The sensing mechanism 5 is mounted on the side of the feeding mechanism 2 facing the feeding direction of the rough tube, serving as a trigger mechanism for the mandrel self-centering mechanism 4 and the feeding mechanism 2.

[0032] Reference Figure 2 , Figure 3 The feeding mechanism 2 includes a roller box 21, two rotating seats 22 rotatably connected to the roller box 21, a feeding roller 23 rotatably connected to the rotating seats 22, a clearance drive assembly 24 for driving the two rotating seats 22 to rotate in opposite directions, and a feeding drive assembly 25 for driving the feeding roller 23 to rotate. The roller box 21 is fixedly connected to the upper side of the frame 1. The two rotating seats 22 are distributed vertically. The feeding roller 23 is located on the side of the rotating seat 22 away from the roller box 21. A V-shaped groove is provided in the middle of the outer edge of the feeding roller 23 to facilitate the clamping of the rough tube by the two feeding rollers 23.

[0033] Reference Figure 4 , Figure 5 The obstacle avoidance drive assembly 24 includes a drive component 241 mounted on the roller box 21, a drive rack 242 connected to the drive component 241, and a drive gear 243 fixedly sleeved on the outside of the rotating seat 22. The drive component 241 is a hydraulic cylinder, with its cylinder body fixedly connected to the upper side of the roller box 21. The piston rod extends downward into the interior of the roller box 21 and is fixedly connected to the drive rack 242, thus enabling the drive component 241 to drive the drive rack 242 to slide up and down. A slide rail 211 is fixedly connected to the inner wall of the upper end of the roller box 21. The slide rail 211 has a U-shaped cross-section, and the drive rack 242 is slidably connected to the slide rail 211. The slide rail 211 provides guidance for the sliding of the drive rack 242, ensuring smooth transmission.

[0034] Two drive gears 243 mesh with each other, and the drive rack 242 meshes with the drive gear 243 located on the upper side. The drive member 241 can drive the drive rack 242 to move up and down, thereby driving the drive gear 243 located on the upper side to rotate, and the drive gear 243 located on the lower side to rotate in the opposite direction, so that the two rotating seats 22 rotate towards or away from each other, realizing the adjustment of the spacing of the feed roller 23, so that the rough tube will not hit the feed roller 23 when passing through.

[0035] Reference Figure 3 , Figure 5 The rotating seat 22 includes a hollow shaft 221 through which the drive shaft 253 passes, a seat body 222 fixedly connected to the hollow shaft 221, and a cover 223 fixedly connected to the seat body 222. The hollow shaft 221 is rotatably connected to the side wall of the roller box 21 near the feed roller 23 via a bearing. A vertically arranged partition 212 is fixedly connected to the inner side of the roller box 21, and the end of the rotating seat 22 away from the feed roller 23 is rotatably connected to the partition 212 via a bearing, so that the rotating seat 22 receives good support. The seat body 222 is fixedly connected to the end of the hollow shaft 221 located outside the roller box 21, and the cover 223 is fixedly connected to the side of the seat body 222 away from the roller box 21 via bolts. The axis of the feed roller 23 is offset from that of the hollow shaft 221 so that when the rotating seat 22 rotates, it drives the two feed rollers 23 to move closer together or further apart.

[0036] Reference Figure 6 , Figure 7 The feeding drive assembly 25 includes a drive motor 251 mounted on one side of the roller box 21, a drive gear 252 connected to the output shaft of the drive motor 251, a drive shaft 253 rotatably passing through the inside of the rotating seat 22, a driven gear 254 fixedly connected to one end of the drive shaft 253, a transmission gear 255 fixedly connected to the other end of the drive shaft 253, a rotating shaft 256 fixedly connected to the feed roller 23, and a rotating gear 257 connected to the rotating shaft 256.

[0037] The drive motor 251 is fixedly connected to the roller box 21 on the side opposite to the feed roller 23. Its output shaft extends into the roller box 21 and is fixedly connected to the drive gear 252. Two driven gears 254 mesh, with the drive gear 252 meshing with the driven gear 254 located on the lower side. When the drive motor 251 is started, it drives the drive gear 252 to rotate, causing the two driven gears 254 to rotate in opposite directions, thereby driving the two drive shafts 253 to rotate within the rotating seat 22. The transmission gear 255 and the rotating gear 257 are both located inside the seat 222. The rotating shaft 256 extends into the seat 222 and is fixedly connected to the rotating gear 257, which meshes with the transmission gear 255. After the drive shaft 253 rotates, it drives the transmission gear 255 and the rotating gear 257 to rotate, thus rotating the two feed rollers 23 and driving the raw pipe feed.

[0038] Reference Figure 6 , Figure 7 The end of the drive shaft 253 furthest from the rotating seat 22 is rotatably connected to a cover 258 via a bearing. The cover 258 is fixedly connected to the side wall of the roller box 21 opposite to the rotating seat 22. The rotating shaft 256 is rotatably connected to the seat 222 via a bearing, and the drive shaft 253 is rotatably connected to the seat 222 via a bearing. The drive shaft 253 is well supported, and the drive shaft 253 and the rotating seat 22 can rotate independently without interfering with each other, ensuring smooth feeding of the rough tube.

[0039] Reference Figure 2 The sensing mechanism 5 includes a support frame 51 for the rough tube to pass through. A sensor 52 for detecting the position of the rough tube is fixedly connected to the support frame 51. The support frame 51 is fixedly connected to the side of the roller box 21 facing the direction of the rough tube feed. The sensor 52 is a proximity switch that can sense the approach of the end of the rough tube. The sensor 52 is electrically connected to the drive motor 251 and the drive component 241 through a controller. The signal sensed by the sensor 52 is fed back to the controller. The controller then calculates the time when the rough tube approaches the feed roller 23 based on the movement speed of the rough tube, and controls the drive component 241 and the drive motor 251 to work accordingly.

[0040] Reference Figure 8 The core rod support mechanism 3 includes two supports 31 fixedly connected to the upper side of the frame 1. A core rod support groove 32 is fixedly connected between the upper sides of the two supports 31. The core rod support groove 32 is V-shaped, and a nylon pad 33 is fixedly connected to the inner side of the upper surface of the core rod support groove 32. The core rod support mechanism 3 provides good support for the core rod and can support long and heavy core rods.

[0041] Reference Figure 8 , Figure 9 The core rod self-centering mechanism 4 includes a mounting base 41 fixedly connected to the frame 1, a slide plate 42 vertically slidably connected to the mounting base 41, a lifting component 43 for driving the slide plate 42 to rise and fall, a lower centering wheel 44 rotatably connected to the upper end of the slide plate 42, swing arms 45 disposed on both sides of the lower centering wheel 44, and side centering wheels 46 rotatably connected to the swing arms 45. The mounting base 41 includes a centering roller 411 and a cover plate 412. The centering roller 411 is fixedly connected to the frame 1, and the cover plate 412 is fixedly connected to the centering roller 411 by bolts. The slide plate 42 is slidably connected to the inner side of the centering roller 411.

[0042] The lifting component 43 is a hydraulic cylinder, with the cylinder body fixedly connected to the frame 1. The piston rod is positioned upwards and fixedly connected to the slide plate 42, thus the lifting component 43 can drive the slide plate 42 to move up and down. The lower centering wheel 44 and the two side centering wheels 46 are arranged in an inverted triangular shape, which can effectively clamp and center the support rod.

[0043] Reference Figure 9 , Figure 10 The middle part of the swing arm 45 is rotatably connected to the centering roller 411, the upper end of the swing arm 45 is rotatably connected to the side centering wheel 46, and the lower end of the swing arm 45 is rotatably connected to the rotating wheel 47. Inclined surfaces 421 are provided on both sides of the upper end of the slide plate 42, so that the width of the slide plate 42 decreases from bottom to top at the inclined surfaces 421, and the rotating wheel 47 abuts against the inclined surfaces 421. A fixing member 48 is fixedly connected to the lower end of the swing arm 45 on the side opposite to the cover plate 412, and the centering roller 411 is provided with a movable hole 4111 through which the fixing member 48 passes. A tension spring 49 is connected between the two fixing members 48, and the tension spring 49 applies an elastic force to the two fixing members 48 to move in opposite directions.

[0044] When the lifting member 43 moves the sliding plate 42 downward, the lower centering wheel 44 moves downward, and the lower ends of the two swing arms 45 are pulled closer together by the tension spring 49. The two side centering wheels 46 move away from each other, causing the lower centering wheel 44 and the two side centering wheels 46 to open. Similarly, when the lifting member 43 moves the sliding plate 42 upward, the lower centering wheel 44 and the two side centering wheels 46 tighten. In other embodiments, the number of centering wheels can be increased.

[0045] The sensor 52 is connected to the lifting component 43 through a controller. After the sensor 52 senses the signal, the controller performs calculations and triggers the lifting component 43 to move when the rough tube approaches the core rod self-centering mechanism 4.

[0046] The implementation principle of the mandrel self-centering device for cold rolling mill in this application embodiment is as follows: In the initial state, the avoidance drive component 24 drives the two rotating seats 22 to rotate in opposite directions, which increases the distance of the feeding roller 23, so that the raw tube can pass through, eliminate the damage caused by the raw tube to the structure, and realize continuous feeding.

[0047] When the raw tube passes the first sensing mechanism 5, a stroke calculation is triggered. When the calculation indicates that the end of the raw tube is about to pass the feed roller 23, the drive component 241 moves the drive rack 242, which in turn causes the two rotating seats 22 to rotate in opposite directions. This causes the feed roller 23 to clamp the raw tube, and the drive motor 251 drives the feed roller 23 to rotate, thus feeding the raw tube. Subsequently, when the raw tube passes the second sensing mechanism 5, the same action is triggered, achieving clamping and feeding of the raw tube.

[0048] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A mandrel self-centering device for a cold rolling mill, comprising a frame (1), wherein a plurality of feeding mechanisms (2) are spaced apart along the raw tube feeding direction on the frame (1), characterized in that: A core rod support mechanism (3) and a core rod self-centering mechanism (4) are provided between adjacent feeding mechanisms (2). A sensing mechanism (5) for detecting the tube end position is provided on the side of the feeding mechanism (2) facing the raw tube feeding direction. The feeding mechanism (2) includes a roller box (21), two rotating seats (22) rotatably connected to the roller box (21), a feeding roller (23) rotatably connected to the rotating seats (22), a clearance drive assembly (24) for driving the two rotating seats (22) to rotate towards or away from each other, and a feeding drive assembly (25) for driving the feeding roller (23) to rotate. The axis of the feeding roller (23) is offset from the axis of rotation of the rotating seat (22). The avoidance drive assembly (24) is used to drive the two rotating seats (22) to rotate in opposite directions in the initial state, so that the distance between the feeding roller (23) increases so that the rough pipe can pass through; and after the rough pipe is in place, the avoidance drive assembly (24) drives the two rotating seats (22) to rotate in opposite directions, so that the feeding roller (23) clamps the rough pipe and realizes the feeding of the rough pipe.

2. The mandrel self-centering device for a cold rolling mill according to claim 1, characterized in that: The avoidance drive assembly (24) includes a drive member (241) mounted on the roller box (21), a drive rack (242) connected to the drive member (241), and a drive gear (243) fixedly sleeved on the outside of the rotating seat (22). The two drive gears (243) mesh with each other, and the drive rack (242) meshes with one of the drive gears (243).

3. The mandrel self-centering device for a cold rolling mill according to claim 2, characterized in that: The inner side of the roller box (21) is connected to a slide rail (211), and the drive rack (242) is slidably connected to the slide rail (211).

4. The mandrel self-centering device for a cold rolling mill according to claim 2, characterized in that: A partition plate (212) is fixedly connected to the inner side of the roller box (21), and the end of the rotating seat (22) away from the feed roller (23) is rotatably connected to the partition plate (212).

5. The mandrel self-centering device for a cold rolling mill according to claim 1, characterized in that: The feeding drive assembly (25) includes a drive motor (251) mounted on one side of the roller box (21), a drive gear (252) connected to the output shaft of the drive motor (251), a drive shaft (253) passing through the inside of the rotating seat (22), a driven gear (254) connected to one end of the drive shaft (253), a transmission gear (255) connected to the other end of the drive shaft (253), a rotating shaft (256) connected to the feed roller (23), and a rotating gear (257) connected to the rotating shaft (256). The two driven gears (254) mesh with each other, the drive gear (252) meshes with one of the driven gears (254), and the transmission gear (255) meshes with the rotating gear (257).

6. The mandrel self-centering device for a cold rolling mill according to claim 5, characterized in that: The end of the drive shaft (253) away from the rotating seat (22) is rotatably connected to a cover (258), and the cover (258) is fixedly connected to the side wall of the roller box (21) away from the rotating seat (22). The rotating seat (22) includes a hollow shaft (221) through which the drive shaft (253) passes, a seat body (222) fixedly connected to the hollow shaft (221), and a cover body (223) fixedly connected to the seat body (222). The transmission gear (255) and the rotating gear (257) are both located inside the seat body (222).

7. The mandrel self-centering device for a cold rolling mill according to claim 1, characterized in that: The core rod self-centering mechanism (4) includes a mounting base (41) connected to the frame (1), a sliding plate (42) vertically slidably connected to the mounting base (41), a lifting component (43) for driving the sliding plate (42) to rise and fall, a lower centering wheel (44) rotatably connected to the upper end of the sliding plate (42), a swing arm (45) set on both sides of the lower centering wheel (44), and a side centering wheel (46) rotatably connected to the swing arm (45). The upper end of the sliding plate (42) is provided with inclined surfaces (421) on both sides. The lower end of the swing arm (45) is connected to a rotating wheel (47) that abuts against the inclined surface (421). The lower end of the swing arm (45) is connected to a fixing component (48). A tension spring (49) is connected between the two fixing components (48).

8. The mandrel self-centering device for a cold rolling mill according to claim 7, characterized in that: The mounting base (41) includes a centering roller (411) and a cover plate (412) connected to the centering roller (411). The slide plate (42) and the swing arm (45) are both connected to the centering roller (411). The centering roller (411) is provided with a movable hole (4111) through which the fixing member (48) passes.

9. The mandrel self-centering device for a cold rolling mill according to claim 1, characterized in that: The core rod support mechanism (3) includes a support (31) connected to the frame (1), a core rod slot (32) connected to the upper side of the support (31), and a nylon pad (33) connected to the inner side of the core rod slot (32).

10. The mandrel self-centering device for a cold rolling mill according to claim 1, characterized in that: The sensing mechanism (5) includes a support frame (51) for the passage of the stubble, and the support frame (51) is connected to a sensor (52) for detecting the position of the stubble.

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