Pinch roll structure for plate rolling line and assembly method

Abstract

The application discloses a pinch roll structure of a plate rolling production line and an assembling method.The structure comprises a roll body and a roll shaft, the end face of the roll body is provided with a counterbore, the shaft end of the roll shaft is provided with a limiting fixing disc, the end face of the limiting fixing disc is provided with a stepped disc, the limiting fixing disc is in interference fit with the end face counterbore of the roll body, the end face pin hole of the limiting fixing disc and the end face pin hole of the counterbore are in transition fit with a positioning pin, the stepped disc is in interference fit with the inner cavity of the roll body, the stepped disc is provided with an axial groove, a radial groove, an axial steam discharge channel and a radial steam discharge channel, the axial groove and the radial groove are provided with an axial sealing ring and a radial sealing ring, and the radial steam discharge channel is provided with a spherical sealing pad, a plastic sphere and a hollow screw rod.The method adopts a room temperature hot assembling mode, the roll body is assembled with the limiting fixing disc and the stepped disc after being heated, and the roll body and the roll shaft are formed into an integral pinch roll.The structure and the assembling method effectively improve the concentricity of the roll body and the roll shaft, prolong the service life of the pinch roll and improve the quality of the produced plate.

Description

Technical Field

[0001] This invention relates to the field of metallurgical equipment technology, and in particular to a pinch roll structure and assembly method for a rolling mill production line. Background Technology

[0002] Pinch rolls are one of the most important and essential components of a plate rolling production line. The geometric precision of the pinch rolls is a crucial factor in determining the production of high-quality plate materials, and their standard service life in high-temperature and humid environments is a key factor in determining plate yield. Pinch rolls are mainly composed of a roll body and a roll shaft. The roll body has countersunk holes at both ends, and the roll shaft has a limiting and fixing disc. During assembly, the limiting and fixing disc is positioned within the countersunk holes, and a planar sealing ring is installed between the limiting and fixing disc and the countersunk holes, making the roll body and roll shaft a single unit. The concentricity accuracy of the pinch roll and the roller shaft is controlled by the fit between the limiting plate and the countersunk hole on the end face of the roll. When there is an error in the fit between the limiting plate and the countersunk hole on the end face of either end of the pinch roll, it will be difficult to keep the concentricity of the roll and the roller shafts at both ends within the accuracy error range. Alternatively, if the pinch roll is in a high-temperature working environment, the expansion coefficients of the roll and the roller shaft may be inconsistent, which will also cause the concentricity accuracy of the roll and the roller shafts at both ends to exceed the design accuracy error range. Or, if the pinch roll is used for a long time in an impact working environment, it will also cause a slight uneven gap to appear between the limiting plate and the countersunk hole on the end face of the roll, causing the concentricity accuracy of the roll and the roller shafts at both ends to exceed the standard operating value range. All of the above abnormalities will affect the output, quality, and efficiency of the rolling mill production line. Meanwhile, during actual production, the continuous impact of the flowing sheet material on the rollers can cause micro-cracks to appear on the rollers. External steam can then penetrate the inner cavity of the rollers through these cracks, leading to rust and corrosion. Alternatively, damage to the planar sealing ring between the limiting and fixing disc and the countersunk hole on the roller end face can also allow steam to enter the inner cavity of the rollers, causing the entire pinch roll to lose its original standard dynamic balance. Consequently, the quality of the produced sheet material fails to meet premium standards. Therefore, traditional pinch rolls have a short service life, severely impacting the efficient operation of the rolling mill production line and reducing the quality of the produced sheet material. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a pinch roll structure and assembly method for a rolling mill production line. This structure and assembly method overcome the defects of traditional pinch rolls, effectively improve the concentricity of the roll body and the roll shaft, prevent the intrusion of external steam, ensure the efficient operation of the rolling mill production line, and improve the service life of the pinch roll and the quality of the produced plate.

[0004] To solve the above technical problems, the pinch roll structure of the rolling mill production line of the present invention includes a roll body and a roll shaft. The end face of the roll body is provided with a countersunk hole, and the end of the roll shaft is provided with a limiting and fixing plate. The limiting and fixing plate is located on the end face of the countersunk hole. The end face of the limiting and fixing plate is provided with a stepped disc. The end face of the countersunk hole is provided with symmetrically spaced screw holes and pin holes. The end face of the limiting and fixing plate is provided with symmetrically spaced through holes and pin holes. The stepped disc is located in the inner cavity of the roll body and is interference-fitted. Fastening bolts and positioning pins are screwed into the through holes and pin holes on the end face of the limiting and fixing plate and the screw holes and pin holes on the end face of the countersunk hole, respectively. An axial sealing ring is provided between the end face of the limiting and fixing plate and the end face of the countersunk hole. The outer ring of the stepped disc is connected to the inner cavity of the roll body. A radial sealing ring is provided. The bottom and middle part of the outer ring of the stepped disc are respectively provided with axial groove and radial groove. An axial exhaust channel is provided at the axial center and a radial exhaust channel is provided in the radial direction. The axial groove contacts the countersunk hole plane of the roller body end face to form a sealing part. The axial sealing ring is located in the axial groove. The radial groove contacts the inner cavity of the roller body to form a circular sealing part. The radial sealing ring is located in the radial groove. The axial exhaust channel and the radial exhaust channel are connected. The radial exhaust channel is located between the axial groove and the radial groove. A spherical sealing gasket is provided at the bottom of the radial exhaust channel and a hollow screw is provided at the top through a threaded connection. A plastic ball is provided on the spherical sealing gasket. A spring is provided between the plastic ball and the hollow screw.

[0005] Furthermore, the pin holes on the end face of the limiting and fixing plate and the pin holes on the end face are at least two and arranged symmetrically, and the end of the positioning pin is provided with a guide radius and transitionally fits with the pin hole.

[0006] Furthermore, the fastening bolts on the end face of the limiting fixing plate and the end face of the countersunk hole are fine-thread bolts, and the nut end is provided with an anti-loosening through hole. A steel wire is inserted into the anti-loosening through hole and knotted to form a stop locking mechanism.

[0007] Furthermore, an annealed copper flat sealing gasket is provided between the end face of the limiting and fixing plate and the end face of the countersunk hole.

[0008] Furthermore, the hollow screw is an internal hexagonal screw, and at the contact point between the spring and the plastic sphere, the spring is partially inserted into the plastic sphere.

[0009] Furthermore, the inner cavity of the roller is coated with an inorganic high-temperature resistant and corrosion-resistant coating to form a high-temperature resistant and corrosion-resistant protective layer.

[0010] An assembly method for the above-mentioned pinch roller structure includes the following steps:

[0011] Step 1: Hoist the roller body into the heating furnace. Set the temperature inside the heating furnace to 120-130℃. Heat the roller body in the heating furnace for 40-45 minutes to ensure that the roller body is heated evenly.

[0012] Step 2: Hoist the evenly heated roller onto the installation platform and place it upright, using brackets to support it and ensure that the roller is placed securely.

[0013] Step 3: Insert the positioning pin into the pin hole on the end face of the roller body countersunk hole, and the positioning pin and the pin hole should be in a transition fit state.

[0014] Step 4: Install the axial sealing ring into the axial groove of the stepped disc. The axial sealing ring and the axial groove should fit tightly without any looseness.

[0015] Step 5: Install the radial sealing ring into the radial groove of the stepped disc. The radial sealing ring and the radial groove should fit tightly without any looseness.

[0016] Step 6: Install the annealed copper flat sealing gasket on the end face of the limiting and fixing plate, and ensure that the annealed copper flat sealing gasket and the end face of the limiting and fixing plate have an effective sealing contact surface with no defects in the contact surface;

[0017] Step 7: Insert the limiting and fixing plate with axial sealing ring, radial sealing ring and annealed copper flat sealing gasket vertically into the countersunk hole on the end face of the roller body through the positioning pin with guiding function. The stepped disc is located in the inner cavity of the roller body. Use fastening bolts to fasten the limiting and fixing plate to the end face of the roller body.

[0018] Step 8: When the temperature of the heated roller body drops to the ambient temperature, use a torque wrench again to symmetrically tighten all the fastening bolts to the standard requirements. At this time, the limit fixing plate is positioned with the countersunk hole on the end face of the roller body through an interference fit, the pin hole on the end face of the limit fixing plate and the pin hole on the end face of the countersunk hole are positioned with the positioning pin through a transition fit, and the stepped disc is positioned with the inner cavity of the roller body through an interference fit, ensuring the initial high-precision coaxiality of the roller body and the roller shaft when the overall pinch roller is assembled.

[0019] Furthermore, after the overall pinch roll assembly is completed, a dynamic balance test is performed on the overall pinch roll. For pinch rolls that do not meet the standard, a balance block is welded at a suitable position on the roll body according to the dynamic balance test results.

[0020] Because the pinch roll structure and assembly method of the rolling mill production line of this invention adopts the above-mentioned technical solution, the structure includes a roll body and a roll shaft. The end face of the roll body is provided with a countersunk hole, and the end of the roll shaft is provided with a limiting and fixing plate. The end face of the limiting and fixing plate is provided with a stepped disc. The limiting and fixing plate is interference-fitted with the countersunk hole on the end face of the roll body. The pin hole on the end face of the limiting and fixing plate and the pin hole on the end face of the countersunk hole are transition-fitted with the positioning pin. The stepped disc is interference-fitted with the inner cavity of the roll body. The stepped disc is provided with an axial groove, a radial groove, an axial exhaust channel, and a radial exhaust channel. An axial sealing ring and a radial sealing ring are provided in the axial groove and the radial groove. A spherical sealing gasket, a plastic ball, and a hollow screw are provided in the radial exhaust channel. This method adopts a room temperature hot assembly method. After the roll body is heated, the limiting and fixing plate and the stepped disc are assembled, so that the roll body and the roll shaft form an integral pinch roll. This structure and assembly method overcome the defects of traditional pinch rolls, effectively improve the concentricity of the roll body and the roll shaft, avoid the intrusion of external steam, ensure the efficient operation of the rolling mill production line, improve the service life of the pinch roll, and improve the quality of the produced plate. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0022] Figure 1 This is a schematic diagram of the pinch roll structure of the rolling mill production line of the present invention;

[0023] Figure 2 This is a schematic diagram showing the connection between the roller shaft, the limiting and fixing disc, and the stepped disc in this structure;

[0024] Figure 3 for Figure 2 A cross-sectional schematic diagram;

[0025] Figure 4 This is a schematic diagram of the roller body in this structure;

[0026] Figure 5 This diagram shows the axial and radial grooves on the stepped disk in this structure.

[0027] Figure 6 This is a schematic diagram of the spherical sealing gasket in this structure;

[0028] Figure 7 This is a schematic diagram of the hollow screw in this structure. Detailed Implementation

[0029] Implementation, for example Figures 1 to 7As shown, the pinch roll structure of the rolling mill production line of the present invention includes a roll body 1 and a roll shaft 2. The end face of the roll body 1 is provided with a countersunk hole 11. The end of the roll shaft 2 is provided with a limiting fixing plate 21. The limiting fixing plate 21 is located on the end face of the countersunk hole 11. The end face of the limiting fixing plate 21 is provided with a stepped disc 22. The end face of the countersunk hole 11 is symmetrically provided with screw holes 12 and pin holes 13 at intervals. The end face of the limiting fixing plate 21 is symmetrically provided with through holes 23 and pin holes 24 at intervals. The stepped disc 22 is located in the inner cavity 14 of the roll body and is interference-fitted. Fastening bolts 3 and positioning pins 4 are screwed into the through holes 23 and pin holes 24 on the end face of the limiting fixing plate 21 and the screw holes 12 and pin holes 13 on the end face of the countersunk hole 11, respectively. An axial sealing ring 5 is provided between the end face of the limiting fixing plate 21 and the end face of the countersunk hole 11. The outer ring of the stepped disc 22 is connected to the inner cavity of the roll body 1. A radial sealing ring 6 is provided. The bottom and middle parts of the outer ring of the stepped disc 22 are respectively provided with an axial groove 25 and a radial groove 26. An axial exhaust channel 27 is provided at the axial center and a radial exhaust channel 28 is provided in the radial direction. The axial groove 25 contacts the countersunk hole 11 plane on the end face of the roller body 1 to form a sealing part. The axial sealing ring 5 is located in the axial groove 25. The radial groove 26 contacts the inner cavity 14 of the roller body to form a circular sealing part. The radial sealing ring 6 is located in the radial groove 26. The axial exhaust channel 27 and the radial exhaust channel 28 are connected, and the radial exhaust channel 28 is located between the axial groove 25 and the radial groove 26. A spherical sealing gasket 7 is provided at the bottom of the radial exhaust channel 28, and a hollow screw 8 is provided at the top through a threaded connection. A plastic ball 9 is provided on the spherical sealing gasket 7, and a spring 10 is provided between the plastic ball 9 and the hollow screw 8.

[0030] Preferably, there are at least two pin holes 24 on the end face of the limiting fixing plate 21 and pin holes 13 on the end face of the countersunk hole 11, which are arranged symmetrically. The end of the positioning pin 4 is provided with a guide rounded corner and transitionally engages with the pin holes 24 and 13.

[0031] Preferably, the fastening bolt 3 of the end face of the limiting fixing plate 21 and the end face of the countersunk hole 11 is a fine thread bolt, and the nut end is provided with an anti-loosening through hole. A steel wire is inserted into the anti-loosening through hole and knotted to form a stop locking mechanism.

[0032] Preferably, an annealed copper flat sealing gasket 211 is provided between the end face of the limiting and fixing plate 21 and the end face of the countersunk hole 11.

[0033] Preferably, the hollow screw 8 is an internal hexagonal screw, and the spring 10 is partially inserted into the plastic ball 9 at the contact point with the plastic ball 9.

[0034] Preferably, the inner cavity 14 of the roller is coated with an inorganic high-temperature resistant and corrosion-resistant protective layer.

[0035] An assembly method for the above-mentioned pinch roller structure includes the following steps:

[0036] Step 1: Hoist the roller body into the heating furnace. Set the temperature inside the heating furnace to 120-130℃. Heat the roller body in the heating furnace for 40-45 minutes to ensure that the roller body is heated evenly.

[0037] Step 2: Hoist the evenly heated roller onto the installation platform and place it upright, using brackets to support it and ensure that the roller is placed securely.

[0038] Step 3: Insert the positioning pin into the pin hole on the end face of the roller body countersunk hole, and the positioning pin and the pin hole should be in a transition fit state.

[0039] Step 4: Install the axial sealing ring into the axial groove of the stepped disc. The axial sealing ring and the axial groove should fit tightly without any looseness.

[0040] Step 5: Install the radial sealing ring into the radial groove of the stepped disc. The radial sealing ring and the radial groove should fit tightly without any looseness.

[0041] Step 6: Install the annealed copper flat sealing gasket on the end face of the limiting and fixing plate, and ensure that the annealed copper flat sealing gasket and the end face of the limiting and fixing plate have an effective sealing contact surface with no defects in the contact surface;

[0042] Step 7: Insert the limiting and fixing plate with axial sealing ring, radial sealing ring and annealed copper flat sealing gasket vertically into the countersunk hole on the end face of the roller body through the positioning pin with guiding function. The stepped disc is located in the inner cavity of the roller body. Use fastening bolts to fasten the limiting and fixing plate to the end face of the roller body.

[0043] Step 8: When the temperature of the heated roller body drops to the ambient temperature, use a torque wrench again to symmetrically tighten all the fastening bolts to the standard requirements. At this time, the limit fixing plate is positioned with the countersunk hole on the end face of the roller body through an interference fit, the pin hole on the end face of the limit fixing plate and the pin hole on the end face of the countersunk hole are positioned with the positioning pin through a transition fit, and the stepped disc is positioned with the inner cavity of the roller body through an interference fit, ensuring the initial high-precision coaxiality of the roller body and the roller shaft when the overall pinch roller is assembled.

[0044] Preferably, after the overall pinch roll is assembled, a dynamic balance test is performed on the overall pinch roll. For pinch rolls that do not meet the standard, a balance block is welded at a suitable position on the roll body according to the prompts of the dynamic balance test.

[0045] In this structure, the stepped disc 22 is 200mm long and its diameter is 0.15-0.20mm larger than the inner diameter of the roller body cavity 14, ensuring that the interference fit meets the design requirements and conforms to the one-time positioning standard, thus achieving one-time positioning. After the stepped disc 22 and the roller body cavity 14 are hot-assembled and cooled at room temperature, they maintain an interference fit, ensuring strong biting force and friction. This gives the overall pinch roll a longer-lasting high-precision concentricity, extending the service life of the pinch roll in high-temperature and harsh working environments, and providing high-yield, high-efficiency, and high-quality performance.

[0046] Two pin holes 24 are made at symmetrical positions on the limiting and fixing plate 21. The two pin holes 24 are required to be in an absolutely symmetrical position on the limiting and fixing plate 21. The depth of the pin holes 24 is 1 / 2 of the thickness of the limiting and fixing plate 21. The roughness of all pin holes is within the design range. The positioning pin 4 maintains a transition fit with the roller body pin hole 13 and the limiting and fixing plate pin hole 24 to ensure that the roller shaft 2 at both ends and the roller body 3 achieve high-precision concentricity requirements. This is a secondary positioning.

[0047] Alternatively, three pin holes 24 can be made at the equal division positions of the limiting and fixing plate 21. The three pin holes 24 are required to be at the absolutely equal division positions of the limiting and fixing plate 21. The number of pin holes depends on the size of the limiting and fixing plate area and the accuracy requirements.

[0048] Based on the inner diameter of the roller pin hole 13 and the pin hole 24 of the limiting and fixing plate 21, a positioning pin 4 with rounded corners is manufactured. The positioning pin 4 is tempered to the designed hardness using relevant processes, and the surface roughness is within the design range. The rounded corners have a good guiding effect.

[0049] Based on the precise inner diameter of the countersunk hole 11 of the roller body, the outer diameter of the limiting fixing plate 21 is set to be 0.15 to 0.20 mm larger than the inner diameter of the countersunk hole 11 of the roller body. The contact surface between the limiting fixing plate 21 and the countersunk hole 11 of the roller body is rounded with a radius of radius R2. After the hot assembly and cooling at room temperature, there is a good interference fit between the limiting fixing plate 21 and the countersunk hole 11 of the roller body, so that the overall pinch roll maintains high-precision concentricity for a long time in the high-temperature working environment. This is a three-stage positioning.

[0050] The connection between the limiting and fixing plate 21 and the roller body 1 is optimized by changing the original coarse thread fastening bolt 3 to a fine thread bolt, which can effectively eliminate the phenomenon of easy loosening of the fastening bolt 3.

[0051] The sealing gasket material of the limiting and fixing plate 21 is optimized by replacing the original high-temperature resistant paper gasket with a 0.5mm thick annealed copper flat sealing gasket 211. This ensures the flatness of the limiting and fixing plate 21, the annealed copper flat sealing gasket 211, and the roller body countersunk hole 11 when clamped together, and ensures the precise concentricity of the roller shafts 2 and the roller body 1 at both ends. The annealed copper flat sealing gasket 211 effectively prevents damage in the high-temperature steam working environment, which would result in a poor seal between the limiting and fixing plate 21 and the roller body countersunk hole 11. This would allow steam from the external atmospheric pressure zone to enter the inner cavity 14 of the roller body through the defective gap, disrupting the standard dynamic balance of the pinch roller. This is a primary sealing step.

[0052] An axial groove 25 is made at an appropriate position at the bottom of the stepped disc 22. The axial groove 25 has a depth of 5mm and a width of 8mm. It is required that the axial groove 25 effectively seals the surface of the roller body countersunk hole 11. Based on the dimensions of the axial groove 25, an axial sealing ring 5 is made. The axial sealing ring 5 has a width of 8mm and a thickness of 7mm. It is required that when the axial sealing ring 5 is tightened and squeezed, it can effectively fill the gap between the roller body countersunk hole 11 and the limiting fixing plate 21, ensuring good sealing between the limiting fixing plate 21 and the roller body countersunk hole 11, and preventing steam from the external steam atmospheric pressure zone C from entering the inner cavity 14 of the roller body through the defective gap. This is a secondary seal.

[0053] A radial groove 26 is made in the middle of the stepped disc 22 (the number of radial grooves can be adjusted according to the actual production system requirements). The radial groove 26 is 5mm deep and 8mm wide, and it is required that the radial groove 26 effectively contacts the annular sealing part of the inner cavity 14 of the roller body. Based on the dimensions of the radial groove 26, a radial sealing ring 6 is made. The radial sealing ring 6 is 8mm wide and 7mm thick. It is required that when the radial sealing ring 6 is tightened and squeezed, it can contact the inner cavity 14 of the roller body with a strong expansion force, ensuring good sealing between the stepped disc 22 and the inner cavity 14 of the roller body, and preventing steam from the medium-pressure steam zone B of the inner cavity from being forced into the inner cavity 14. This is a three-stage sealing.

[0054] An axial exhaust channel 27 is drilled at the center of the stepped disc 22. The axial exhaust channel 27 has a diameter of Φ18mm and a depth of 150mm. The inner wall of the axial exhaust channel 27 is required to be smooth, meeting the design roughness standard. A radial exhaust channel 28 is drilled between the axial groove 25 and the radial groove 26. The radial exhaust channel 28 has a diameter of Φ12mm and a depth of 1 / 2 the diameter of the stepped disc 22. The radial exhaust channel 28 is connected to the axial exhaust channel 27. The inner wall of the radial exhaust channel 28 is smooth, meeting the design roughness standard.

[0055] A spherical sealing gasket 7 is installed in the radial exhaust channel 28, with the sealing opening of the spherical sealing gasket 7 facing the plastic sphere 9, and the spherical surface of the plastic sphere 9 recessed into the sealing opening of the spherical sealing gasket. A spring 10 is placed inside the radial exhaust channel 28, with one end of the spring 10 partially inserted into the plastic sphere 9. A hollow screw 8 is threaded onto the top of the radial exhaust channel 28.

[0056] Axial exhaust channel 27, radial exhaust channel 28, and correspondingly provided spherical sealing gasket 7, plastic sphere 9, spring 10, and hollow screw 8 are used for exhausting steam from the inner cavity 14 of the roller. When steam from the external atmospheric pressure zone C enters the inner cavity 14 of the roller with a higher temperature through the gap between the roller 1 and the limiting fixing plate 21, the minor cracks on the surface of the roller 1, or other reasons (caused by the direct contact between the roller 1 and the high-temperature plate), the steam expands rapidly within the limited space of the inner cavity 14 of the roller. The rapidly expanding steam preferentially enters through the axial exhaust channel 27. The interconnected radial exhaust channel 28 and the sealing port of the spherical sealing gasket 7 allow the rapidly expanding steam to reach a high pressure, pushing the plastic sphere 9 and causing the spring 10 to contract. An exhaust gap is formed between the sealing port of the spherical sealing gasket 7 and the plastic sphere 9. Steam from high-pressure zone A is discharged through this gap and the hollow screw into the medium-pressure zone B (a small space with very little or no steam) of the roller cavity 14. The steam from medium-pressure zone B then passes through the damaged axial sealing ring 5 and the annealed copper flat sealing gasket 211 to the external atmospheric steam zone C. The steam exhaust path of the roller cavity 14 is from the high-pressure zone A into the medium-pressure zone B, and finally to the external atmospheric steam zone C, completing the steam exhaust process of the roller cavity 23. The positions of the high-pressure zone A, the medium-pressure zone B, and the external atmospheric steam zone C are as follows: Figure 5 As shown. Because the pinch roller operates in a high-temperature steam environment for a long time, a high-pressure steam zone and a medium-pressure steam zone are formed inside the pinch roller. This structure takes advantage of the pressure difference between the high-pressure steam zone inside the pinch roller and the normal-pressure steam zone outside. Automatic steam is discharged by setting axial steam discharge channel and radial steam discharge channel. The high-pressure steam inside the pinch roller forces out the steam that abnormally enters the roller body.

[0057] This structure and method ensure that the various geometric parameters of the pinch roll meet the process requirements, guaranteeing that the pinch roll has long-term standard dynamic balance, precise geometric parameters, and excellent corrosion resistance in hot and humid working environments. It has the advantages of high quality, high output, and high efficiency compared to similar pinch rolls, thereby ensuring the efficient operation of the rolling mill production line, improving the service life of the pinch roll and the quality of the produced plates.

Claims

1. A pinch roll structure for a rolling mill production line, comprising a roll body and a roll shaft, wherein the end face of the roll body is provided with a countersunk hole, and the end of the roll shaft is provided with a limiting and fixing plate, the limiting and fixing plate being located on the end face of the countersunk hole, characterized in that: The end face of the limiting and fixing disc is provided with a stepped disc, the end face of the countersunk hole is provided with symmetrically spaced screw holes and pin holes, the end face of the limiting and fixing disc is provided with symmetrically spaced through holes and pin holes, the stepped disc is located in the inner cavity of the roller body and is interference-fitted, fastening bolts and positioning pins are screwed into the through holes and pin holes of the limiting and fixing disc end face and the screw holes and pin holes of the countersunk hole end face respectively, an axial sealing ring is provided between the end face of the limiting and fixing disc and the end face of the countersunk hole, a radial sealing ring is provided between the outer ring of the stepped disc and the inner cavity of the roller body, and the bottom and middle part of the outer ring of the stepped disc are respectively provided with axial grooves and radial grooves. An axial exhaust channel is provided at the axial center, and a radial exhaust channel is provided in the radial direction. The axial groove contacts the countersunk hole plane on the end face of the roller body to form a sealing part, and the axial sealing ring is located in the axial groove. The radial groove contacts the inner cavity of the roller body to form a circular sealing part, and the radial sealing ring is located in the radial groove. The axial exhaust channel and the radial exhaust channel are connected, and the radial exhaust channel is located between the axial groove and the radial groove. A spherical sealing gasket is provided at the bottom of the radial exhaust channel, and a hollow screw is provided at the top through a threaded connection. A plastic ball is provided on the spherical sealing gasket, and a spring is provided between the plastic ball and the hollow screw.

2. The pinch roll structure of the rolling mill production line according to claim 1, characterized in that: The pin holes on the end face of the limiting and fixing plate and the pin holes on the end face are at least two and arranged symmetrically. The end of the positioning pin is provided with a guide rounded corner and transitions with the pin hole.

3. The pinch roll structure of the rolling mill production line according to claim 1, characterized in that: The fastening bolts on the end face of the limiting fixing plate and the end face of the countersunk hole are fine thread bolts, and the nut end is provided with an anti-loosening through hole. A steel wire is inserted into the anti-loosening through hole and knotted to form a stop locking mechanism.

4. The pinch roll structure of the rolling mill production line according to claim 1, characterized in that: An annealed copper flat sealing gasket is provided between the end face of the limiting and fixing plate and the end face of the countersunk hole.

5. The pinch roll structure of the rolling mill production line according to claim 1, characterized in that: The hollow screw is an internal hexagonal screw, and the spring is partially inserted into the plastic sphere at the contact point with the plastic sphere.

6. The pinch roll structure of the rolling mill production line according to claim 1, characterized in that: The inner cavity of the roller is coated with an inorganic high-temperature resistant and anti-corrosion coating to form a high-temperature resistant and anti-corrosion protective layer.

7. A method for assembling the pinch roller structure according to any one of claims 1 to 6, characterized in that... This method includes the following steps: Step 1: Hoist the roller body into the heating furnace. Set the temperature inside the heating furnace to 120-130℃. Heat the roller body in the heating furnace for 40-45 minutes to ensure that the roller body is heated evenly. Step 2: Hoist the evenly heated roller onto the installation platform and place it upright, using brackets to support it and ensure that the roller is placed securely. Step 3: Insert the positioning pin into the pin hole on the end face of the roller body countersunk hole, and the positioning pin and the pin hole should be in a transition fit state. Step 4: Install the axial sealing ring into the axial groove of the stepped disc. The axial sealing ring and the axial groove should fit tightly without any looseness. Step 5: Install the radial sealing ring into the radial groove of the stepped disc. The radial sealing ring and the radial groove should fit tightly without any looseness. Step 6: Install the annealed copper flat sealing gasket on the end face of the limiting and fixing plate, and ensure that the annealed copper flat sealing gasket and the end face of the limiting and fixing plate have an effective sealing contact surface with no defects in the contact surface; Step 7: Insert the limiting and fixing plate with axial sealing ring, radial sealing ring and annealed copper flat sealing gasket vertically into the countersunk hole on the end face of the roller body through the positioning pin with guiding function. The stepped disc is located in the inner cavity of the roller body. Use fastening bolts to fasten the limiting and fixing plate to the end face of the roller body. Step 8: When the temperature of the heated roller body drops to the ambient temperature, use a torque wrench again to symmetrically tighten all the fastening bolts to the standard requirements. At this time, the limit fixing plate is positioned with the countersunk hole on the end face of the roller body through an interference fit, the pin hole on the end face of the limit fixing plate and the pin hole on the end face of the countersunk hole are positioned with the positioning pin through a transition fit, and the stepped disc is positioned with the inner cavity of the roller body through an interference fit, ensuring the initial high-precision coaxiality of the roller body and the roller shaft when the overall pinch roller is assembled.

8. The assembly method of the pinch roller structure according to claim 7, characterized in that: After the overall pinch roll assembly is completed, a dynamic balance test is performed on the overall pinch roll. For pinch rolls that do not meet the standard, a balance block is welded at a suitable position on the roll body according to the dynamic balance test results.

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