Hydraulic damping type step pad lifting and balancing device of hot rolling strip steel rolling mill

Abstract

The utility model relates to the technical field of metallurgy hot rolling equipment, in particular to a hydraulic damping type step pad lifting and balancing device of a hot rolling strip mill. The problems of vibration deviation, short service life and the like of a traditional device are solved, and the plate and strip rolling precision and the equipment stability are improved. The device comprises a plurality of elastic devices arranged below a lower stepped pad of the rolling mill, and the elastic devices are fixed on a sliding plate of a rack through flange plates. The elastic device comprises a high-pressure-resistant hydraulic oil cylinder, a piston rod is arranged in the hydraulic oil cylinder, labyrinth type clearance sealing is adopted, and an adjustable throttling valve is arranged on the hydraulic oil cylinder. The oil cylinder is vertically installed to replace a traditional flat spring, rigid supporting of a mechanical spring is replaced through the fluid dynamic damping characteristic, a high-reliability closed-loop control system is formed, the stability and precision problems in the rolling line adjusting process are solved, and gapless precise regulation and control of the step pad are achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of metallurgical hot rolling equipment, specifically a hydraulic damping stepped pad lifting and balancing device for hot-rolled strip steel mills. Background Technology

[0002] As a core component of steel manufacturing, the precise control of the step pads on the rolling mill floor directly impacts the strip thickness accuracy and equipment stability of the hot rolling production line. Traditional hot rolling mills commonly employ flat spring-type step pad balancing devices (such as...). Figure 2 As shown in the diagram, this device dynamically adjusts the gap between the slide plate and the pressure head device through the elastic deformation of 40 flat springs. However, in actual service, this technology has revealed several technical bottlenecks: First, the flat springs are prone to plastic creep under cyclic alternating loads, causing the fluctuation amplitude of the preset separation gap between the stepped pad and the pressure head to exceed the design allowable value. This results in unexpected distortion of the rolling force loading curve, increasing the difficulty of signal filtering and indirectly affecting the response speed of the AGC system. Second, the spring material undergoes age hardening under long-term high-temperature conditions (approximately 50-70℃), and its fatigue life is typically less than 8000 working hours. The resulting deviation in rolling force after failure affects the accuracy of pressure detection. These technical defects have severely restricted the improvement of the automation level of hot rolling production lines and have become a common industry problem restricting the thickness tolerance control of strip steel products. Utility Model Content

[0003] The purpose of this invention is to address the aforementioned shortcomings by providing a hydraulically damped stepped pad lifting and balancing device for hot-rolled strip steel mills. This solves the problems of vibration deviation and short lifespan inherent in traditional devices, thereby improving the rolling accuracy of strip steel and the stability of the equipment.

[0004] The technical solution of this utility model is: a hydraulic damping stepped pad lifting and balancing device for a hot-rolled strip steel mill, comprising multiple elastic devices installed under the lower stepped pad of the mill, the elastic devices being fixed to the frame slide plate via flanges. Each elastic device includes a high-pressure resistant hydraulic cylinder, with a piston rod inside the cylinder and a labyrinth-type gap seal, and an adjustable flow valve on the hydraulic cylinder.

[0005] The beneficial effects of this utility model are as follows: 1. The vertical installation of the hydraulic cylinder replaces the traditional flat spring, and the fluid dynamic damping characteristics replace the rigid support of the mechanical spring, forming a highly reliable closed-loop control system. This solves the stability and accuracy problems in the adjustment process of the rolling line and achieves precise control of the stepped pad without gaps. 2. The damping coefficient stability is improved by 300% compared with the traditional spring, the life is extended to 17,000 hours (an increase of 112%), the maintenance cycle is doubled, the vibration suppression capability is optimized, and it helps control the thickness tolerance of the strip steel. 3. Through dynamic damping adjustment, high-frequency vibration is effectively suppressed (attenuation rate ≥90%), helping the AGC system to achieve high-precision control with a thickness tolerance ≤±3μm. It has higher reliability, longer maintenance cycle and better dynamic performance, significantly improving the automation level of the hot rolling production line and product quality.

[0006] The embodiments of this utility model will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a simplified structural diagram of the present invention.

[0008] Figure 2 This is a simplified diagram of the improved flat spring arrangement structure. Detailed Implementation

[0009] See Figure 1 The component names are as follows: hydraulic cylinder 5, piston rod 6, adjustable flow valve 7.

[0010] See Figure 2 The component names are as follows: support roller 1, step pad 2, slide plate 3, flat spring 4.

[0011] See Figure 1A hydraulic damping stepped pad lifting and balancing device for a hot-rolled strip steel mill includes multiple elastic devices installed under the lower stepped pad 2 of the mill. These elastic devices are fixed to the frame slide plate 3 via flanges. Each elastic device includes a high-pressure resistant hydraulic cylinder 5, which contains a piston rod 6 and employs a labyrinth-type gap sealing structure. An adjustable flow valve 7 is installed on the hydraulic cylinder 5, allowing for continuous adjustment of the damping coefficient from 0.5 to 2 kN·s / mm by changing the throttling orifice diameter, adapting to different rolling conditions. This device is vertically installed at the original location of the flat spring 4, replacing it. During operation, as the support rollers fall, the stepped pad of the mill comes into close contact with the damper (i.e., this device). The slide plate 3 directly compresses the hydraulic cylinder 5, and the high-pressure oil in the damper pushes the piston rod 6 to generate hydraulic elasticity, balancing the upper stepped pad 2 and eliminating gaps. The compressibility of hydraulic oil is utilized to create hydraulic elasticity. When the mill needs to lift the stepped pad 2, pre-pressurized high-pressure oil pushes the piston rod 6 upward, ensuring a smooth and controllable lifting process. The damping force can be pre-adjusted. During normal rolling, the maximum pressure of each hydraulic damper does not exceed 400 kg. The 40 sets of hydraulic dampers continuously provide a stable balancing force, creating a balanced gap to eliminate pressure, offset rolling force fluctuations, and achieve balanced pressure output, thus ensuring smooth operation. This device employs a periodic replacement process, involving offline seal replacement and oil replenishment. The entire process is simple, efficient, and performed offline, achieving a 20,000-hour maintenance-free cycle. The attenuation rate of high-frequency vibration is significantly better than that of spring devices, providing a stable mechanical environment for accurate detection by the rolling force sensor, effectively suppressing vibration interference with the rolling force, and ensuring the feedback accuracy of the AGC system.

[0012] The sealing system uses perfluoroelastomer (FFKM) seals and a piston rod 6 with laser-clad tungsten carbide coating, resulting in a low coefficient of friction of 0.08~0.12 and high tear resistance.

[0013] The labyrinth-type gap seal (gap ≤ 0.02mm) combined with the pressure-compensating oil film (3~5MPa) can achieve the IP67 protection level without the need for a sealing ring, extending the overall life of the device to more than 17,000 hours, which is 112% better than the traditional flat spring structure.

[0014] The seals and piston rod have a 6-coating that withstands the high-temperature environment of the rolling mill and has a tear strength of ≥35MPa.

[0015] The piston rod 6 has a laser-coated tungsten carbide coating on its surface, which is combined with FFKM sealing rings to form a protective layer; the hydraulic cylinder 5 has labyrinth-type gap sealing grooves (gap 0.02mm) at both ends, and is filled with 3-5MPa pressure oil film to achieve IP67 protection level.

[0016] The hydraulic system uses high-viscosity oil as the energy transmission medium. Its damping coefficient can be continuously matched within the range of 0.5-2kN·s / mm through stepless adjustment of the adjustable flow valve 7, which has stronger adaptability to working conditions compared with mechanical structures with fixed spring stiffness.

[0017] Working principle:

[0018] Liquid inlet stage: High-pressure oil enters the piston chamber from the lower end of the oil cylinder 5, pushing the piston rod 6 upward and causing the stepped pad 2 to rise. The oil generates damping force through the adjustable flow valve 7.

[0019] Balanced state: After the piston rod 6 rises to the preset position, the hydraulic oil forms a dynamic pressure compensation oil film through the labyrinth seal groove, maintaining the stability of the step pad gap elimination force.

[0020] Reset phase: When the pressure is released, the piston rod 6 falls back under the action of the rolling force, and the valve core automatically adjusts the opening to ensure a smooth return.

[0021] The adjustable flow valve 7 is pre-adjusted to the specified pressure range (400KG according to the original design). During the mill step adjustment, the hydraulic system drives the piston rod 6 to push the step pad 2 up, and the oil generates a controllable damping force through the throttling valve core, smoothly separating the pressure. Under normal operation, this device provides a stable balancing force to avoid vibration interference in the rolling force detection.

[0022] The above description is merely a specific embodiment of this utility model, and the various examples do not constitute a limitation on the substantive content of this utility model.

Claims

1. A hydraulic damping stepped pad lifting and balancing device for a hot-rolled strip mill, comprising multiple elastic devices installed under the lower stepped pad (2) of the mill, the elastic devices being fixed to the frame slide plate (3) via flanges, characterized in that... The elastic device includes a high-pressure resistant hydraulic cylinder (5), which has a piston rod (6) and adopts a labyrinth gap sealing structure. An adjustable flow valve (7) is provided on the hydraulic cylinder (5).

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