A rolling mill pressing servo cylinder test system and test device

Abstract

This invention relates to the field of testing technology for servo hydraulic cylinders used in rolling mills. The invention provides a testing system and device for servo hydraulic cylinders used in rolling mills. An internal pressure sensor is installed in the rodless chamber of the cylinder, including an air source assembly for supplying compressed air. The output end of the air source assembly is equipped with a gas pressure reducing valve for adjusting the gas pressure. One end of a gas-liquid converter is connected to the gas pressure reducing valve, and the other end is connected to the rodless chamber of the cylinder. The end of the gas-liquid converter connected to the rodless chamber is filled with hydraulic oil for supplying oil to the rodless chamber of the cylinder so that the internal pressure sensor can obtain liquid pressure parameters. A displacement detection component is installed on the piston rod of the cylinder for detecting the movement state of the piston rod and generating a displacement signal. The controller is electrically connected to the gas pressure reducing valve, the internal pressure sensor, and the displacement detection component. This invention solves the technical problem of low minimum starting pressure accuracy in existing purely hydraulic cylinder testing technologies.

Description

Technical Field

[0001] This invention relates to the field of testing technology for rolling mill pressing servo cylinders, specifically to a testing system and testing device for rolling mill pressing servo cylinders. Background Technology

[0002] The servo cylinder of a rolling mill is a hydraulic actuator in rolling equipment. It converts hydraulic energy into mechanical energy to achieve actions such as roll pressing, balancing, bending, and shifting. Its minimum starting pressure directly reflects the cylinder's overall friction characteristics, sealing compatibility, and assembly quality, and is a core indicator determining the accuracy of the rolling mill's AGC (Automatic Gauge Control) thickness control system, the uniformity of strip thickness, and the smoothness of low-speed movement. The minimum starting pressure of the cylinder is usually tested by the cylinder manufacturer before shipment, and the testing equipment used is typically a pure hydraulic test.

[0003] In the prior art, Chinese utility model patent CN216382090U discloses a performance testing platform for hydraulic cylinders. This platform uses three independent motor-pump components to supply oil under various operating conditions. During minimum starting pressure testing, a squirrel-cage three-phase asynchronous motor drives and controls a gear pump, with a proportional pressure reducing valve controlling the output pressure, thus improving testing accuracy and reducing system energy consumption. However, in practical use, this testing method suffers from inherent oil pulsation characteristics due to the use of a gear pump. In the 0~0.6MPa micro-pressure testing range, where the minimum starting pressure of the rolling mill cylinder is concentrated, the pump pulsation is significantly amplified, causing periodic fluctuations in the pressure curve. This makes it difficult to accurately capture the critical starting point of the cylinder from rest to continuous stable movement, resulting in poor test repeatability and failing to meet the ±0.05MPa accuracy requirement for AGC cylinders. Summary of the Invention

[0004] To overcome the above-mentioned defects, embodiments of the present invention provide a rolling mill press servo cylinder testing system and testing device, which solves the technical problem of low minimum starting pressure accuracy of cylinders in pure hydraulic testing in the prior art.

[0005] A rolling mill pressing servo cylinder testing system is used to detect the minimum starting pressure of the rolling mill cylinder. An internal pressure sensor is installed in the rodless chamber of the cylinder, comprising: An air supply assembly for providing compressed air, wherein the output end of the air supply assembly is provided with a gas pressure reducing valve for adjusting the gas pressure; The gas-liquid converter has one end connected to the gas pressure reducing valve and the other end connected to the rodless chamber of the oil cylinder. The end of the gas-liquid converter connected to the rodless chamber is filled with hydraulic oil and is used to supply oil to the rodless chamber of the oil cylinder so that the pressure sensor in the chamber can obtain the liquid pressure parameters. The displacement detection component is installed on the piston rod of the hydraulic cylinder to detect the movement state of the piston rod and generate a displacement signal. The controller is electrically connected to the gas pressure reducing valve, the intracavity pressure sensor, and the displacement detection component, respectively. The controller is configured to: adjust the gas pressure reducing valve so that the pressure at the output end of the gas pressure reducing valve gradually increases until the displacement signal of the displacement detection component is received, and then record the pressure value of the intracavity pressure sensor.

[0006] As a further technical solution, a hydraulic component is also included, which can input hydraulic oil into the rod chamber of the cylinder to simulate the back pressure that the cylinder experiences during use.

[0007] As a further technical solution, the hydraulic assembly includes an oil tank, a pump group, and a control valve group, wherein the pump group and the control valve group are both electrically connected to the controller; The oil tank and the rodless chamber of the cylinder are connected by a rodless oil supply circuit and a rodless oil return circuit, and the oil tank and the rod chamber of the cylinder are connected by a rod oil supply circuit and a rod oil return circuit; the testing system is used to form the no-load minimum starting pressure test state and the back pressure starting pressure test state. When in the no-load minimum starting pressure test state, the control valve group is used to control the air source assembly and the rodless chamber of the oil cylinder to be connected through the air-liquid converter, so that the rodless chamber can be pressurized, and control the rod return oil circuit to be connected, thereby enabling the controller to obtain the first pressure parameter through the chamber pressure sensor; When in the back pressure start-up pressure test state, the control valve group is used to control the connection between the air source assembly and the rodless chamber of the oil cylinder, and to control the connection between the rod oil supply circuit and the rod chamber, thereby enabling the controller to obtain the second pressure parameter through the chamber pressure sensor.

[0008] As a further technical solution, the control valve group includes a pressure reducing valve, which is disposed on the rod oil supply line connecting the rod chamber and the hydraulic assembly. The pressure reducing valve is used to generate a stable back pressure in the rod chamber, and the pressure reducing valve can set the overflow flow rate so that the rod chamber can maintain a stable pressure when the piston of the cylinder moves.

[0009] As a further technical solution, the control valve group also includes a servo valve, which is located in the rodless oil supply line so that the servo valve can adjust the supply pressure in the rodless chamber.

[0010] As a further technical solution, both the rod-type oil supply circuit and the rodless oil supply circuit have independent ball valves, and the rod-type oil supply circuit and the rodless oil supply circuit have a junction point. The pump set is located before the junction point so that the pump set can be connected to the rod-type oil supply circuit and / or the rodless oil supply circuit through the control valve set. A first filter is provided between the pump unit and the junction of the rod-type oil supply circuit and the rodless oil supply circuit. The first filter is used for coarse filtration of hydraulic oil. A second filter is provided at the oil inlet of the servo valve and is located on the rodless oil supply circuit. The second filter is used for fine filtration of hydraulic oil.

[0011] As a further technical solution, the control valve group also includes a first solenoid valve and a second solenoid valve. The first solenoid valve is located between the pump group, the rod-type oil supply circuit and the rodless oil supply circuit, and is used to control the overall opening and closing of the rod-type oil supply circuit and the rodless oil supply circuit. The second solenoid valve is located on the rodless return oil line and is used to control the opening and closing of the rodless return oil line.

[0012] A rolling mill pressing servo cylinder testing device, comprising: performing cylinder testing using the aforementioned rolling mill pressing servo cylinder testing system, including: The base extends upward and is provided with several rods, and the rods have steps; A back pressure plate is slidably disposed on the rod, and the back pressure plate is located above the step and can be supported by the step. A placement space for accommodating the hydraulic cylinder is formed between the back pressure plate and the base. A load-bearing member is disposed on the rod and located above the back pressure plate. An elastic member is provided between the load-bearing member and the back pressure plate. The elastic member is used to provide a force to the back pressure plate near the step. The elastic force of the elastic member and the gravity of the back pressure plate are used to simulate the back pressure applied to the cylinder by the roller.

[0013] As a further technical solution, the load-bearing member is slidably connected to the rod, and the load-bearing member can slide close to the back pressure plate and compress the elastic member to adjust the back pressure on the oil cylinder.

[0014] As a further technical solution, it also includes: An adjusting nut, threaded onto the rod, is able to approach and press against the load-bearing member to push the load-bearing member to move.

[0015] The beneficial effects of this invention are as follows: A stable and adjustable air pressure is supplied to the gas-liquid converter via the air source assembly and a precision gas pressure reducing valve. The diaphragm then converts the air pressure into oil pressure without pulsation, eliminating the inherent pressure pulsation of the hydraulic pump's oil supply in the 0-0.6 MPa micro-pressure range. This allows the rodless chamber pressure to increase continuously and slowly at a controlled rate. Combined with a high-precision displacement detection component, the system can accurately capture the critical starting point of the cylinder from a standstill to continuous and stable movement, improving the accuracy and repeatability of the minimum starting pressure test while maintaining a small device size.

[0016] The hydraulic components form a control loop through the relief valve and the pressure reducing valve, which can provide stable and controllable back pressure to the rod chamber, simulating the self-weight of the roll and bearing housing, so that the test conditions are consistent with the actual working conditions of the cylinder, improving the working condition reproduction of the test data and the reference value of the mill control system.

[0017] The rolling mill pressing servo cylinder testing device utilizes the superposition of the elastic force of the elastic element and the gravity of the back pressure plate to apply simulated back pressure to the cylinder independently of the hydraulic system. The adjusting nut, in conjunction with the thread, allows for adjustment of the back pressure magnitude. The structure is simple and intuitive, serving as an independent verification method for hydraulic back pressure simulation, or working in conjunction with the back pressure generated by hydraulic components to achieve the effect of adjusting the back pressure as needed. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of the present invention and these drawings without any creative effort.

[0019] Figure 1 This is a schematic diagram of the rolling mill pressing servo cylinder testing system of the present invention; Figure 2 for Figure 1 Enlarged structural diagram at point A in the middle; Figure 3 for Figure 1 Enlarged structural diagram at point B; Figure 4 This is a schematic diagram illustrating the principle of the minimum starting pressure test for the no-load rolling mill cylinder of the present invention; Figure 5 This is a schematic diagram illustrating the principle of the starting pressure test after applying back pressure to the rolling mill cylinder according to the present invention; Figure 6 This is a schematic diagram illustrating the principle of the slow descent of the rolling mill cylinder according to the present invention; Figure 7 This is a schematic diagram illustrating the principle of rapid descent of the rolling mill cylinder according to the present invention; Figure 8 This is a schematic diagram illustrating the principle of how the hydraulic cylinder is stably held at a certain position according to the present invention. Figure 9 This is a cross-sectional view of the servo cylinder testing device for rolling mill pressing according to the present invention; Figure 10 This is a top view schematic diagram of the servo cylinder testing device for rolling mill pressing according to the present invention; Figure 11 This is a schematic diagram of the overall structure of the rod member of the present invention; In the diagram: 01, hydraulic cylinder; 011, rodless chamber; 012, rod chamber. 100. Gas source components, 210. Gas-liquid converter; 211. Isolation diaphragm; 220. Gas pressure reducing valve. 300. Intracavitary pressure sensor. 400. Hydraulic components; 410. Oil tank; 420. Pump assembly; 430. Control valve assembly; 431. Relief valve; 432. First solenoid valve; 433. Second solenoid valve; 434. Servo valve; 435. Ball valve; 4351. First ball valve; 4352. Second ball valve; 4353. Third ball valve; 4354. Fourth ball valve; 4355. Fifth ball valve; 4356. Sixth ball valve; 4357. Seventh ball valve; 4358. Eighth ball valve; 4359. Ninth ball valve; 436. Pressure reducing valve; 440. Pressure sensor; 450. First filter; 460. Second filter. 500. Displacement detection component 600. Base; 610. Rod; 611. Step. 700, back pressure plate, 800. Load-bearing component; 810. Elastic component; 820. Adjusting nut. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0021] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0022] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0025] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] This embodiment relates to the field of testing technology for servo hydraulic cylinders on rolling mills, and particularly to a gas-liquid combination testing system and supporting testing device for detecting the minimum starting pressure of rolling mill cylinders. This technical solution can be applied to the cylinder re-inspection stage before the assembly of the entire rolling mill, accurately obtaining the minimum starting pressure of the cylinder under no-load and back pressure conditions to verify the cylinder's friction characteristics, sealing compatibility, and assembly quality. On the one hand, it can eliminate cylinders whose minimum starting pressure does not meet requirements due to excessive transportation or storage time; on the other hand, the control system debugging of the rolling mill cylinders does not need to wait until the customer completes the assembly of the customized rolling mill on-site before repeated adjustments are made. Through the rolling mill servo hydraulic cylinder testing system and testing device of this embodiment, the cylinder can be simulated under actual back pressure, allowing the system adjustment to be completed at the rolling mill manufacturer. After the rolling mill is assembled on-site, only a simple trial run is required, eliminating the need for repeated testing and adjustments.

[0027] When configuring a rolling mill system, the minimum starting pressure is a critical parameter. Deviations in the minimum starting pressure can lead to problems such as poor accuracy, slow response, and poor stability in the rolling mill cylinder control system. The cylinder testing systems used by cylinder manufacturers are complex and require a large area. Furthermore, the minimum starting pressure tests conducted by cylinder manufacturers are performed under no-load conditions, which differs from the actual operating conditions where the rolling mill cylinder must withstand at least the weight of the roll itself. Therefore, deviations in the minimum starting pressure are inevitable in practical use.

[0028] like Figures 1-8As shown, the present invention also provides a rolling mill pressing servo cylinder testing system, comprising an air source component 100, an air-liquid converter 210, a gas pressure reducing valve 220, a displacement detection component 500, an intracavity pressure sensor 300, a hydraulic component 400, and a controller.

[0029] The air source assembly 100 provides compressed air with stable pressure, and its output is connected to the input of the gas pressure reducing valve 220 via a pipeline. The gas pressure reducing valve 220 regulates the air pressure input to the gas-liquid converter 210, and its output is connected to the air chamber of the gas-liquid converter 210. The gas-liquid converter 210 converts gas pressure into liquid pressure without pulsation, and its oil chamber is connected to the rodless chamber 011 of the tested cylinder 01 via a pipeline. The chamber pressure sensor 300 is installed at the oil port of the rodless chamber 011 of the cylinder 01 to detect the liquid pressure in the rodless chamber 011 in real time. The displacement detection assembly 500 is installed at the end of the piston rod of the cylinder 01 to detect minute displacements of the piston rod. The hydraulic assembly 400 is connected to the rod chamber 012 of the cylinder 01 to provide controllable back pressure to the rod chamber 012 to simulate the weight of the rolls and bearing housing borne by the cylinder 01 in an actual rolling mill. The controller is electrically connected to each of the electrically controlled valves in the gas pressure reducing valve 220, the cavity pressure sensor 300, the displacement detection component 500, and the hydraulic component 400, and is used to automatically execute the test process and collect and process data.

[0030] In practical use, the compressed air output from the air source assembly 100 is slowly pressurized at a controlled rate by the gas pressure reducing valve 220 and enters the air chamber of the gas-liquid converter 210. The isolation diaphragm 211 inside the gas-liquid converter 210 transmits the air pressure equally to the oil chamber, driving hydraulic oil into the rodless chamber 011 of the cylinder 01. The rod chamber 012 of the cylinder 01 is pre-established with a stable back pressure by the hydraulic assembly 400. As the pressure in the rodless chamber 011 continues to rise, when the driving force is sufficient to overcome the static friction, sealing resistance, and the reverse force generated by the back pressure in the rod chamber 012, the piston rod begins to produce continuous and smooth displacement. After the displacement detection assembly 500 captures this displacement signal, the controller immediately records the pressure value of the chamber pressure sensor 300 at this moment, which is the minimum starting pressure under this back pressure condition.

[0031] Regarding the displacement detection component 500's capture of displacement signals, the controller compares the displacement signals received with those received by the piston rod to determine whether the displacement is continuous and stable. The criteria for determining "continuous and stable displacement" are as follows: upon receiving the displacement signal from the displacement detection component 500, the controller immediately records the value from the intracavity pressure sensor 300. Then, by adjusting the gas pressure reducing valve 220, the gas source component 100 maintains the current gas pressure output. If the piston continues to move smoothly for a certain distance, the value recorded by the controller from the intracavity pressure sensor 300 is considered valid. If the piston does not continue to move a certain distance or exhibits significant fluctuations, the value recorded by the controller from the intracavity pressure sensor 300 is considered invalid. The controller records the valid values, and after multiple tests, takes the average of the valid values ​​as the final detection value.

[0032] Because the gas pressure reducing valve 220 has precise adjustment in the micro-pressure range and no pressure pulsation, the hydraulic pressure transmitted to the rodless chamber 011 of the cylinder 01 via the gas-liquid converter 210 is also stable and without fluctuation. This allows the critical starting point to be accurately captured, effectively solving the problem of poor test repeatability caused by pressure pulsation when the existing hydraulic pump directly supplies oil.

[0033] Optionally, the air source assembly 100 includes an air filter, a pressure regulating valve, and an air receiver connected in sequence. The air filter removes moisture, oil mist, and solid impurities from the compressed air, preventing contaminants from entering the gas-liquid converter 210 and affecting the sealing performance of the isolation diaphragm 211. The pressure regulating valve is used to initially set the air source outlet pressure, while the air receiver acts as a buffer and stabilizer, enabling the air source assembly 100 to output stable compressed air with a pressure range of 0.01~0.15MPa. In factories without a centralized air source, the air source assembly 100 can employ an independent mobile air compressor equipped with a refrigerated dryer to further improve the air source quality.

[0034] The gas pressure reducing valve 220 is preferably a precision pneumatic pressure reducing valve with a pressure adjustment range of 0 to 0.6 MPa and a minimum adjustable pressure of 0.005 MPa. This valve exhibits excellent continuous adjustment characteristics within the 0 to 0.6 MPa range, with no significant dead zone or pressure step. The controller controls the output pressure of the gas pressure reducing valve 220 via analog signals or digital communication, enabling it to continuously and slowly increase at a set rate of 0.001 to 0.01 MPa / s. Due to the pressure balance on both sides of the isolation diaphragm 211 of the gas-liquid converter 210 and the extremely low piston movement resistance, the stable gas pressure output by the gas pressure reducing valve 220 is converted into oil pressure with almost no lag, fundamentally eliminating pump source pulsation and ensuring the stability of pressure supply within the 0 to 0.6 MPa micro-pressure range.

[0035] The gas-liquid converter 210 adopts a diaphragm structure with an internal isolation diaphragm 211 that divides the inner cavity into a gas chamber and an oil chamber. The gas chamber is connected to the outlet of the gas pressure reducing valve 220, and the oil chamber is connected to the rodless chamber 011 of the cylinder under test 01 via a pipeline. The oil chamber is pre-filled with hydraulic oil of the same working medium as the cylinder under test 01 to ensure that the test conditions are consistent with the actual working conditions. It is necessary to ensure that there is no gas in the hydraulic oil in the oil chamber to avoid pressure fluctuations during the test.

[0036] The oil chamber and the gas chamber of the gas-liquid converter 210 have the same pressure-bearing area on both sides to ensure that the pressure in the oil chamber and the gas chamber is the same. The specific structural form of the gas-liquid converter 210 is prior art and will not be described in detail here.

[0037] The hydraulic assembly 400 provides stable back pressure to the rod chamber 012 of the cylinder 01 and also functions to drive the piston rod of the cylinder 01. (Refer to...) Figure 1 The hydraulic assembly 400 includes an oil tank 410, a pump assembly 420, a control valve assembly 430, and a pressure sensor 440.

[0038] Pump unit 420 uses a gear pump driven by a three-phase asynchronous motor to provide pressurized oil to the system. The oil tank 410 is equipped with an air filter and a level gauge on the top and an oil drain valve on the bottom to maintain pressure balance inside and outside the tank and facilitate routine maintenance.

[0039] The control valve assembly 430 includes a relief valve 431, a first solenoid valve 432, a second solenoid valve 433, a servo valve 434, multiple ball valves 435, and a pressure reducing valve 436. The relief valve 431 is installed on the output line of the pump assembly 420 and is used as a safety valve to limit the maximum system pressure and prevent abnormal pressure rises from damaging the equipment.

[0040] The oil inlet of the first solenoid valve 432 is connected to the output of the pump unit 420, and the oil outlet is connected to the oil inlet of the servo valve 434 and the rod chamber 012 of the cylinder 01. By controlling the opening and closing of the first solenoid valve 432, two working states can be achieved: pumping oil into the rod chamber 012 and the rodless chamber 011, and stopping pumping oil into the rod chamber 012 and the rodless chamber 011.

[0041] One end of the second solenoid valve 433 is connected to the rodless chamber 011 of the oil cylinder 01, and the other end is connected to the oil tank 410. By controlling the opening and closing of the second solenoid valve 433, the rodless chamber 011 can be in two states: oil discharge and pressure holding.

[0042] The first solenoid valve 432 is preferably a two-position four-way solenoid directional valve, such as Figure 7As shown, when the first solenoid valve 432 is in the first working position on the right, the pressure oil output by the pump unit 420 can be guided to the rod chamber 012 or the rodless chamber 011 of the cylinder 01 as needed, for pumping oil into the rod chamber 012 or the rodless chamber 011; for example Figure 1 As shown, the first solenoid valve 432 is a three-position four-way valve. The right first position is the working state of the first solenoid valve 432 described above. The middle position and the left first position can be selected as either the left first position state of the two-position four-way valve. When the first solenoid valve 432 is in the left first position as described later, it can be either the middle position or the left first position of the first solenoid valve 432 shown in the figure. When the first solenoid valve 432 is in the left second working position, the communication between the rodless chamber 011 and the rod chamber 012 of the cylinder 01 and the pump group 420 is cut off by the first solenoid valve 432, and the rodless chamber 011 and the rod chamber 012 can be unloaded into the oil tank 410 through the first solenoid valve 432.

[0043] The second solenoid valve 433 is preferably a two-position four-way solenoid directional valve, such as Figure 8 As shown, when the second solenoid valve 433 is in the first working position on the right, the rodless chamber 011 is directly connected to the oil tank 410, and the hydraulic oil in the rodless chamber 011 can be released quickly, thereby realizing the rapid descent and reset of the cylinder 01 and improving the test cycle efficiency; Figure 8 As shown, when the second solenoid valve 433 is in the second working position, the direct connection between the rodless chamber 011 and the oil tank 410 is closed, and the pressure of the rodless chamber 011 is controlled by the servo valve 434, so that the piston of the oil cylinder 01 can move and stay at any height, simulating the roll gap adjustment during actual use of the rolling mill.

[0044] like Figure 8 As shown, a servo valve 434 is installed on the connection passage between the first solenoid valve 432 and the rodless chamber 011. The servo valve 434 allows the piston of the hydraulic cylinder 01 to rise and remain at a set position. To ensure the cleanliness of the hydraulic fluid entering the servo valve 434, a first filter 450 and a second filter 460 are installed on the pipeline between the first solenoid valve 432 and the servo valve 434. The first filter 450 is located at the outlet end of the first solenoid valve 432, ensuring that all hydraulic oil passing through the first solenoid valve 432 is filtered by the first filter 450, preventing impurities in the hydraulic oil from damaging the chamber of the hydraulic cylinder 01. The filtration accuracy of the first filter 450 is 10μm, used for coarse filtration to remove larger particulate impurities. The second filter 460 is located at the inlet end of the servo valve 434. The filtration accuracy of the second filter 460 is 3μm, used for fine filtration to remove tiny particles, preventing the nozzle-baffle mechanism of the servo valve 434 from jamming and ensuring its dynamic response characteristics and control accuracy.

[0045] The hydraulic oil that enters cylinder 01 directly through the first solenoid valve 432 only needs to be filtered by the first filter 450. However, the hydraulic oil that passes through the first solenoid valve 432 and then the servo valve 434 needs to be filtered by both the first filter 450 and the second filter 460. This two-stage filtration system prevents the servo valve 434 from being affected by impurities in the hydraulic oil and avoids the need for frequent replacement of the second filter.

[0046] The servo valve 434 controls the valve core opening via an electrical signal output from the controller, precisely regulating the flow and pressure entering the rodless chamber 011. During the roll gap adjustment test, the flow and pressure control system established by the servo valve 434 causes the cylinder 01 to move and remain at the set position. The specific structure of the servo valve 434 is existing technology and will not be described in detail here.

[0047] A pressure reducing valve 436 is installed on the oil supply circuit connecting the rod chamber 012 and the oil tank 410. It employs a three-way pressure reducing valve structure and also has an overflow function. During minimum start-up pressure testing, the pump unit 420 pumps oil into the rod chamber 012 through the pressure reducing valve, generating a stable pressure inside the rod chamber 012 to simulate the back pressure caused by the weight of the rolls. Then, the air source assembly 100 continuously pumps compressed air into the gas-liquid converter 210 through the gas pressure reducing valve 220. As the air in the gas-liquid converter 210 increases, the pressure on the gas side gradually rises until the diaphragm in the gas-liquid converter 210 moves downward, pushing the hydraulic oil on the liquid side of the gas-liquid converter 210 towards the rodless chamber 011, thereby causing the piston of the rolling mill cylinder to move upward. After the displacement detection assembly 500 detects the piston movement, the controller collects the detection value from the chamber pressure sensor 300 as the minimum start-up pressure test value.

[0048] During piston movement, the pressure in the rod chamber 012 increases, and the hydraulic oil in the rod chamber 012 can overflow to the oil tank through the pressure reducing valve 436. The pressure reducing valve 436 also prevents the back pressure from fluctuating drastically after the piston starts, thus avoiding interference with the controller's judgment of "continuous and stable displacement" based on the values ​​detected by the displacement detection component 500.

[0049] The pressure reducing valve 436 is preferably an electromagnetic three-way pressure reducing valve. By adjusting the pressure of the pressure reducing valve 436, the rod chamber 012 can be kept at a stable pressure, or the rod chamber 012 can be allowed to overflow due to overpressure.

[0050] The displacement detection component 500 employs a magnetostrictive displacement sensor, with its probe arranged axially along the piston rod of cylinder 01, and a movable magnetic ring fixed to the end of the piston rod. This sensor has a measurement accuracy of ±1μm, a repeatability of ±0.5μm, and a sampling frequency of no less than 1kHz, enabling real-time detection of the micron-level displacement of the piston rod at the moment of startup. Its non-contact measurement principle makes it unaffected by oil or dust, suitable for long-term use in workshop environments, and the absence of mechanical wear ensures consistent long-term testing accuracy.

[0051] The cavity pressure sensor 300 uses a high-precision diffused silicon pressure sensor with a measurement range of 0 to 1 MPa. By directly installing it at the oil port of the rodless cavity 011 of the hydraulic cylinder 01, the pressure transmission path can be shortened to the greatest extent, reducing the impact of pipeline cavity effects on pressure detection hysteresis and ensuring accurate correspondence with the displacement signal sampling time axis, thereby improving the accuracy of minimum starting pressure capture.

[0052] like Figures 9-11 As shown, on the other hand, the present invention also provides a rolling mill pressing servo cylinder testing device. This device tests the rolling mill cylinder using the aforementioned rolling mill pressing servo cylinder testing system, and can also simulate back pressure mechanically. The back pressure simulated by the rolling mill pressing servo cylinder testing device and the back pressure simulated by the rolling mill pressing servo cylinder testing system can act simultaneously or independently. Depending on the actual testing conditions, the operator can arbitrarily combine them to adjust the testing of the effect of different back pressures on the cylinder.

[0053] The rolling mill pressing servo cylinder testing device includes a base 600, four rods 610, a back pressure plate 700, a load-bearing component 800, four elastic components 810, and four adjusting nuts 820.

[0054] The base 600 is a rectangular steel plate, placed horizontally, used to support the tested hydraulic cylinder 01 and the entire testing device. Four rods 610 are vertically fixed to the four corners of the base 600 by threaded connection or welding. Each rod 610 has an integrally formed annular step 611 in the middle, and the upper surface of the step 611 forms a horizontal annular support surface.

[0055] The back pressure plate 700 is a rectangular steel plate with guide holes at its four corners. It slides along the four rods 610 through these guide holes, allowing it to move freely up and down. In its free state, the lower surface of the back pressure plate 700 rests on the upper surface of the step 611, where it is supported, thus creating a space between the back pressure plate 700 and the base 600 to accommodate the tested hydraulic cylinder 01. During testing, the hydraulic cylinder 01 is placed vertically on the base 600, and its piston rod end extends upward under the action of the rolling mill pressing servo hydraulic cylinder testing system, lifting the back pressure plate 700.

[0056] The load-bearing component 800 is also a rectangular steel plate with guide holes at its four corners. It is slidably sleeved on the four rods 610 and located above the back pressure plate 700. Four elastic components 810 are respectively sleeved on the four rods 610 and located between the load-bearing component 800 and the back pressure plate 700. Specifically, the elastic component 810 is a cylindrical helical compression spring or a disc spring, with its two ends contacting the lower surface of the load-bearing component 800 and the upper surface of the back pressure plate 700, respectively.

[0057] Four adjusting nuts 820 are threaded to the top of four rods 610, with the lower surface of each adjusting nut 820 contacting the upper surface of the load-bearing member 800. When the adjusting nut 820 is rotated downwards, it pushes the load-bearing member 800 downwards along the rod 610, compressing the elastic member 810. Its restoring force is transmitted to the piston rod end of the cylinder 01 through the back pressure plate 700. The elastic force of the elastic member 810, combined with the weight of the back pressure plate 700, acts on the piston rod, forming a back pressure simulating the weight of the roll and bearing housing. By changing the screw-in amount of the adjusting nut 820, the compression amount of the elastic member 810 can be continuously adjusted, thereby adjusting the magnitude of the simulated back pressure. This mechanical back pressure simulation method requires no hydraulic power source, has an independent structure, and allows for intuitive adjustment.

[0058] To ensure the accuracy of the above back pressure adjustment method, a pressure sensor can be installed on the step 611 of the back pressure plate 700. In actual use, a stable back pressure condition can be set using the rolling mill pressing servo cylinder testing device. Then, based on the actual test results, the back pressure in the fine-tuning rod cavity 012 can be adjusted through the rolling mill pressing servo cylinder testing system. This method of mechanical coarse adjustment and hydraulic system fine adjustment not only achieves precise back pressure adjustment but also adapts to the back pressure simulation of various rolls with different qualities. Compared to relying solely on the hydraulic system to adjust the back pressure, it reduces energy consumption.

[0059] Secondly, the rolling mill pressing servo cylinder test device, combined with the rolling mill pressing servo cylinder test system, can also simulate the back pressure caused by the gravity of the fixed rolls. The rolling mill pressing servo cylinder test system can simulate the back pressure brought by the raw material passing through the rolls. By adjusting the opening of the pressure reducing valve through electromagnetic control or manual control, the back pressure brought by raw materials of different thicknesses passing through the rolls can be simulated.

[0060] By combining mechanical back pressure and hydraulic back pressure, more simulation tests that better reflect real-world usage scenarios can be achieved, thereby improving the accuracy of simulation tests.

[0061] The controller has multiple preset test modes that can be selected and executed as needed. The following is a combination of... Figures 4 to 8The working process of each mode is explained. For ease of description, the ball valves 435 in the rolling mill pressing servo cylinder test system are divided into the first ball valve 4351, the second ball valve 4352, the third ball valve 4353, the fourth ball valve 4354, the fifth ball valve 4355, the sixth ball valve 4356, the seventh ball valve 4357, the eighth ball valve 4358, and the ninth ball valve 4359.

[0062] Reference Figure 4 During the no-load minimum starting pressure test, ball valves 4356 (sixth), 4358 (eighth), and 4359 (ninth) are opened, while the remaining ball valves 435 are closed. The rod chamber 012 of cylinder 01 is connected to the oil tank, but no back pressure is applied. The controller controls the gas pressure reducing valve 220 to slowly increase the output gas pressure at a rate of 0.005 MPa / s. The gas pressure is converted into oil pressure by the gas-liquid converter 210 and then acts on the rodless chamber 011 of cylinder 01. The chamber pressure sensor 300 and the displacement detection component 500 detect the pressure and displacement in real time, respectively. When the displacement detection component 500 determines that the displacement generated by the piston rod changes from static to moving and continues to move for a period of time, the controller records the reading of the chamber pressure sensor 300 at this moment, which is the no-load minimum starting pressure. After the test is completed, the eighth ball valve 4358 closes and the second ball valve 4352 opens, allowing the pump unit 420 to pump oil into the rod chamber 012. This pushes the hydraulic oil in the rodless chamber 011 towards the gas-liquid converter 210, enabling the piston rod of the cylinder 01 to quickly reset, and the diaphragm in the gas-liquid converter 210 to return to its initial position, facilitating the next test. To improve data reliability, the controller can automatically repeat the above test three times and take the average value as the final result.

[0063] Reference Figure 5During the minimum starting pressure test with back pressure, the first ball valve 4351, the second ball valve 4352, the sixth ball valve 4356, the seventh ball valve 4357, and the ninth ball valve 4359 are opened. The pump group 420 of the hydraulic assembly 400 is started. The controller calculates the required back pressure value based on the preset simulated weight of the roll and bearing housing, and outputs control signals to the pressure reducing valve 436 and the relief valve 431. The set pressure of the relief valve 431 is higher than the set pressure of the pressure reducing valve 436, and the set pressure of the pressure reducing valve 436 is the required back pressure value. The first solenoid valve 432 is switched to the first position on the right. The pump group 420 continuously pumps oil into the rod chamber 012 through the pressure reducing valve 436, so that the hydraulic oil in the rod chamber 012 is maintained at the set pressure of the pressure reducing valve 436 (i.e., the back pressure value brought by the weight of the simulated roll and bearing housing). Then, the hydraulic oil in the rodless chamber 011 is continuously pressurized through the air source assembly 100 and the air-liquid converter 210 until the piston of the cylinder 01 moves. When the piston moves, the pressure in the rod chamber 012 increases, and the hydraulic oil in the rod chamber 012 can overflow to the oil tank through the pressure reducing valve 436, thereby enabling the rod chamber 012 to maintain a stable back pressure. The subsequent controller determines the stable displacement of the piston by detecting the displacement amount by the displacement detection component 500, and uses the recorded pressure value of the chamber pressure sensor 300 as the minimum starting pressure under a specific back pressure.

[0064] Reference Figure 6 The slow descent mode of the hydraulic cylinder is used to reset the piston rod and the gas-liquid converter 210 after the test. First ball valve 4351, second ball valve 4352, sixth ball valve 4356, seventh ball valve 4357, and ninth ball valve 4359 are opened. The controller controls the first solenoid valve 432 to switch to the first position on the right, and the pressurized oil output from the pump unit 420 enters the rod chamber 012 of the hydraulic cylinder 01 through the first solenoid valve 432. Simultaneously, the controller controls the set pressure of the overflow valve 431 to be higher than the set pressure of the gas pressure reducing valve 220. Through the continuous pumping of oil into the rod chamber 012 by the pump unit 420, the hydraulic oil in the rodless chamber 011 is compressed and moves towards the oil chamber of the gas-liquid converter 210, thereby compressing the gas in the gas chamber. The gas pressure in the gas chamber increases until it exceeds the set pressure of the gas pressure reducing valve 220, and the gas escapes. At this time, the piston of the hydraulic cylinder 01 slowly descends as the hydraulic oil enters the rod chamber 012.

[0065] Reference Figure 7 The rapid descent mode of the hydraulic cylinder is used to improve the test cycle time. First ball valve 4351, second ball valve 4352, fifth ball valve 4355, and seventh ball valve 4357 are opened. The controller controls the second solenoid valve 433 to switch to the first position on the right, and the first solenoid valve 432 to switch to the first position on the right. The rodless chamber 011 of the hydraulic cylinder 01 is directly connected to the oil tank 410 through the second solenoid valve 433, and the back pressure quickly disappears. Simultaneously, pressurized oil can be supplied to the rod chamber 012, and the piston rod quickly resets under the combined action of its own weight and oil pressure.

[0066] Reference Figure 8 The hydraulic cylinder positioning mode is used in situations where the piston rod needs to remain in a specific position, such as maintaining a stable roll gap between two rolls during rolling. First ball valve 4351, second ball valve 4352, third ball valve 4353, fourth ball valve 4354, fifth ball valve 4355, and seventh ball valve 4357 are opened. The controller controls the first solenoid valve 432 to switch to the right first position and the second solenoid valve 433 to the left second position. The passages from the rod chamber 012 and the rodless chamber 011 to the hydraulic cylinder 01 via the pump unit 420 are both connected. Both the rod chamber 012 and the rodless chamber 011 are filled with pressurized oil. Through the closed-loop feedback control of the servo valve 434, the piston rod is locked in the set position, facilitating other inspections or maintenance operations.

[0067] The controller can adjust the servo valve 434 based on the detection values ​​of the displacement detection component 500, thereby simulating the working condition of the rolling mill cylinder driving the roll to move and maintain it at a certain set roll gap.

[0068] Optionally, in the combined application of back pressure simulation methods, the hydraulic back pressure provided by the hydraulic component 400 can be combined with the mechanical back pressure provided by the testing device. For example, a basic back pressure can be applied first using the mechanical testing device to simulate the main part of the roll's weight, and then a smaller and finely adjustable additional back pressure can be applied using the hydraulic component 400 to accurately compensate for or simulate frictional differences. This combination method can further reduce the dependence on the dynamic accuracy of the mechanical back pressure system while retaining the ability to make precise adjustments.

[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A rolling mill pressing servo cylinder testing system for detecting the minimum starting pressure of a rolling mill cylinder (01), wherein an internal pressure sensor (300) is provided in the rodless cavity (011) of the cylinder (01), characterized in that, include: An air supply assembly (100) is provided for supplying compressed air, and the output end of the air supply assembly (100) is provided with a gas pressure reducing valve (220) for adjusting the gas pressure. The gas-liquid converter (210) is connected at one end to the gas pressure reducing valve (220) and at the other end to the rodless chamber (011) of the oil cylinder (01). The end of the gas-liquid converter (210) connected to the rodless chamber (011) is filled with hydraulic oil and is used to supply oil to the rodless chamber (011) of the oil cylinder (01) so that the pressure sensor (300) inside the chamber can obtain the liquid pressure parameters. The displacement detection component (500) is installed on the piston rod of the hydraulic cylinder (01) to detect the movement state of the piston rod and generate a displacement signal; The controller is electrically connected to the gas pressure reducing valve (220), the intracavity pressure sensor (300), and the displacement detection component (500), respectively. The controller is configured to: adjust the gas pressure reducing valve (220) to gradually increase the pressure at the output end of the gas pressure reducing valve (220) at a set rate until the displacement signal of the displacement detection component (500) is received, and then record the pressure value of the intracavity pressure sensor (300).

2. The rolling mill pressing servo cylinder testing system according to claim 1, characterized in that, It also includes a hydraulic assembly (400) that can input hydraulic oil into the rod chamber (012) of the cylinder (01) to simulate the back pressure that the cylinder (01) experiences during use.

3. The rolling mill pressing servo cylinder testing system according to claim 2, characterized in that, The hydraulic assembly (400) includes an oil tank (410), a pump group (420), and a control valve group (430), both of which are electrically connected to the controller. The oil tank (410) is connected to the rodless chamber (011) of the cylinder (01) by a rodless oil supply circuit and a rodless oil return circuit, and the oil tank (410) is connected to the rod chamber (012) of the cylinder (01) by a rod oil supply circuit and a rod oil return circuit; the test system is used to form the no-load minimum starting pressure test state and the back pressure starting pressure test state; When in the no-load minimum starting pressure test state, the control valve group (430) is used to control the air source assembly (100) and the rodless chamber (011) of the oil cylinder (01) to be connected through the gas-liquid converter (210), so that it can pressurize the rodless chamber (011) and control the rod return oil circuit to be connected, thereby enabling the controller to obtain the first pressure parameter through the chamber pressure sensor (300); When in the back pressure start-up pressure test state, the control valve group (430) is used to control the air source assembly (100) to connect with the rodless chamber (011) of the oil cylinder (01), and control the rod oil supply circuit and the rod chamber (012) to connect, thereby obtaining the second pressure parameter through the chamber pressure sensor (300).

4. The rolling mill pressing servo cylinder testing system according to claim 3, characterized in that, The control valve assembly (430) includes a pressure reducing valve (436) disposed on the rod oil supply line connecting the rod chamber (012) and the hydraulic assembly (400). The pressure reducing valve (436) is used to generate a stable back pressure in the rod chamber (012), and the pressure reducing valve (436) can set the overflow flow rate so that the rod chamber (012) can maintain a stable pressure when the piston of the cylinder (01) moves.

5. The rolling mill pressing servo cylinder testing system according to claim 3, characterized in that, The control valve assembly (430) also includes a servo valve (434), which is located on the rodless oil supply line so that the servo valve (434) can adjust the supply pressure in the rodless chamber (011).

6. The rolling mill pressing servo cylinder testing system according to claim 5, characterized in that, Both the rod-type oil supply circuit and the rodless oil supply circuit have independent ball valves (435), and the rod-type oil supply circuit and the rodless oil supply circuit have an intersection point. The pump set (420) is located before the intersection point so that the pump set (420) can be connected to the rod-type oil supply circuit and / or the rodless oil supply circuit through the control valve set (430). A first filter (450) is provided between the pump set (420) and the junction of the rod-type oil supply line and the rodless oil supply line. The first filter (450) is used for coarse filtration of hydraulic oil. A second filter (460) is provided at the oil inlet end of the servo valve (434), and the second filter (460) is located on the rodless oil supply line. The second filter (460) is used for fine filtration of hydraulic oil.

7. The rolling mill pressing servo cylinder testing system according to claim 3, characterized in that, The control valve group (430) also includes a first solenoid valve (432) and a second solenoid valve (433). The first solenoid valve (432) is located between the pump group (420), the rod-type oil supply circuit and the rodless oil supply circuit, and is used to control the overall opening and closing of the rod-type oil supply circuit and the rodless oil supply circuit. The second solenoid valve (433) is located on the rodless return oil line and is used to control the opening and closing of the rodless return oil line.

8. A rolling mill pressing servo cylinder testing device, which uses the rolling mill pressing servo cylinder testing system according to any one of claims 1 to 7 to test the cylinder (01), characterized in that, include: The base (600) extends upward and is provided with a plurality of rods (610), and the rods (610) have steps (611). A back pressure plate (700) is slidably disposed on the rod (610), and the back pressure plate (700) is located above the step (611) and can be supported by the step (611). A placement space for accommodating the oil cylinder (01) is formed between the back pressure plate (700) and the base (600). A load-bearing member (800) is disposed on the rod (610) and located above the back pressure plate (700). An elastic member (810) is provided between the load-bearing member (800) and the back pressure plate (700). The elastic member (810) is used to provide the force of the back pressure plate (700) to approach the step (611). The elastic force of the elastic member (810) and the gravity of the back pressure plate (700) are used to simulate the back pressure applied by the roller to the cylinder (01).

9. A testing device for a rolling mill pressing servo cylinder according to claim 8, characterized in that, The load-bearing member (800) is slidably connected to the rod (610). The load-bearing member (800) can slide close to the back pressure plate (700) and compress the elastic member (810) to adjust the back pressure on the cylinder (01).

10. A testing device for a rolling mill pressing servo cylinder according to claim 9, characterized in that, Also includes: An adjusting nut (820) is threaded onto the rod (610). The adjusting nut (820) can approach and press against the load-bearing member (800) to push the load-bearing member (800) to move.

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