Stroke detection device for a rolling mill HGC hydraulic cylinder

Abstract

The utility model discloses a kind of stroke detection devices of rolling mill HGC hydraulic cylinder, belong to metallurgical equipment technical field, including cylinder body, piston body and magnetostrictive displacement sensor.Piston body has the stroke of moving in cylinder body.Magnetostrictive displacement sensor is set to the space inside being covered by cylinder body and piston body.Using the detection device of built-in magnetostrictive displacement sensor, realize the built-in sensor of HGC hydraulic cylinder, avoid sensor direct exposure in harsh environment, while the non-contact and high-precision detection of magnetostrictive displacement sensor improve the stability and service life of oil cylinder stroke detection system.

Description

Technical Field

[0001] This utility model belongs to the field of metallurgical equipment technology, specifically a stroke detection device for HGC hydraulic cylinders in rolling mills. Background Technology

[0002] The heavy plate rolling mill rolls steel plates to corresponding thicknesses according to the different roll gaps in the pass schedule. The roll gaps of the mill consist of the upper roll system roll gap (mechanical pressing and positioning) and the lower roll system roll gap (hydraulic pressing). The hydraulic pressing roll gap is calculated by the HGC hydraulic cylinder through the displacement sensor detected by the displacement sensor installed on it, and then through the zero-point calibration value. There are two HGC hydraulic cylinders in total, located on both sides below the rolls. According to the installation method of the HGC hydraulic cylinder sensor, they can be divided into HGC hydraulic cylinders with built-in sensors and HGC hydraulic cylinders with external sensors. The built-in sensor is installed at the bottom of the cylinder body inside the HGC hydraulic cylinder, and the external sensor is installed on the outer side of the HGC hydraulic cylinder. Two external sensors must be symmetrically arranged along the center of the hydraulic cylinder on each hydraulic cylinder. Compared with the built-in sensor, the installation and replacement of the external sensor does not need to be replaced along with the HGC cylinder. However, the external sensor is exposed to the harsh open environment under the mill stand.

[0003] The external sensors for the HGC hydraulic cylinders in rolling mills primarily utilize Sony's magnetic grating displacement sensors to adapt to the operating environment of the HGC hydraulic cylinders. The sensor mainly consists of a movable magnetic grating, a fixed magnetic head, a sensor body with an elastic telescopic component, and its protective sleeve. When the HGC roll gap increases, the hydraulic cylinder retracts downwards, and the sensor retracts along with it, pressed down by the cylinder head plate. When the HGC roll gap decreases, the hydraulic cylinder rises upwards, and the sensor rises along with the cylinder head plate. During the real-time movement of the roll gap, the magnetic grating inside the sensor changes synchronously with the magnetic head as the cylinder moves, ensuring that the displacement matches the stroke of the hydraulic cylinder.

[0004] The externally mounted Sony magnetic grating displacement sensor, installed under the rolling mill stand, is constantly subjected to the rinsing of various cooling and descaling waters, the high temperatures generated by the high-temperature steel plates in the relatively confined space, the corrosion of water and gasoline contaminants, and the vibrations during the rolling process. This significantly impacts the sensor's reliability and lifespan, resulting in a high failure rate and necessitating regular inspection, maintenance, and out-of-line repairs. Therefore, on the one hand, when a sensor fails or is taken out of service, the sensor, plus specialized tools, weighs approximately 30 kg, and the limited installation and maintenance space requires multiple people to replace it, making installation and maintenance difficult. On the other hand, out-of-service sensors require professional repair companies to disassemble them and replace the internal magnetic grating and magnetic head, leading to long repair cycles and high costs. Utility Model Content

[0005] The purpose of this invention is to provide a stroke detection device for the HGC hydraulic cylinder of a rolling mill, so as to solve the problems mentioned in the prior art.

[0006] A stroke detection device for an HGC hydraulic cylinder in a rolling mill is provided, comprising: Cylinder block; Piston body, which has a stroke that moves within the cylinder; A magnetostrictive displacement sensor is installed inside the space enclosed by the cylinder and piston.

[0007] As a further embodiment of this utility model: the magnetostrictive displacement sensor includes a detection rod and a magnetic ring, the magnetic ring being movably sleeved around the detection rod, the detection rod being disposed on the bottom inner wall of the cylinder, and a bracket being provided between the magnetic ring and the piston body.

[0008] The detection rod is the waveguide core of the magnetostrictive sensor, with its end fixed to the bottom of the cylinder. The magnetic ring slides along the detection rod as the piston moves. When the piston moves, the change in the magnetic ring's position causes a change in the signal time difference inside the sensor, thus measuring the displacement. The bracket is used to fix the position of the magnetic ring relative to the piston, ensuring measurement consistency.

[0009] As a further embodiment of this utility model: the bracket is a columnar structure that extends from the inner wall of the piston body towards the cylinder body and forms a cavity inside the extension body, the magnetic ring is set at the end of the bracket, and the detection rod extends into the inner cavity of the bracket.

[0010] The hollow support structure positions the magnetic ring at the end of the support and allows it to move around the detection rod. When the piston moves, the entire support moves the magnetic ring, achieving magnetic coupling detection of the relative displacement between the magnetic ring and the detection rod. The hollow support forms a radial constraint and enclosure structure for the detection rod, enhancing its protection in harsh environments and preventing radial movement, thus extending its service life.

[0011] As a further embodiment of this utility model, it also includes an elastic element, which is clamped between the cylinder body and the piston body. The elastic element is a spring and is movably sleeved on the periphery of the bracket.

[0012] The elastic element forces the piston body to remain in contact with the cylinder head during hydraulic cylinder lifting and lowering, ensuring the piston body always follows and detects the displacement stroke of the hydraulic cylinder. Through the passive contact of the piston body, no mechanical connection is needed between the piston body and the cylinder head, facilitating disassembly and maintenance and reducing disturbance to the piston body from the hydraulic cylinder. Furthermore, the long rod-shaped structure of the bracket provides radial constraint for the elastic element, enhancing the stability of its expansion and contraction.

[0013] As a further embodiment of this utility model: the inner sidewall of the piston body extends radially inward to form a spring seat, the spring seat serves as a transition structure between the support and the piston body, and the elastic element is clamped between the cylinder body and the spring seat.

[0014] The spring seat provides a stable support end face for the elastic element and can shorten the structural length of the elastic element. The elastic element does not need to be the same length as the detection device, thus avoiding the eccentric instability caused by the excessive length of the elastic element during the compression process.

[0015] As a further embodiment of this utility model: the detection rod is fixedly connected to a closed electronic compartment after passing through the cylinder body, and the electronic compartment is connected to the cylinder body through a flange between the end of the detection rod housing and the cylinder body.

[0016] The detection rod extends outward through the cylinder body, and its outer shell is sealed to the electronic compartment shell via a flange. Its interior is electrically connected to the electronic compartment to achieve signal output. The flange connection ensures sealing and detachability, achieves stable signal output, and prevents oil and gas corrosion.

[0017] As a further embodiment of this utility model, a protective cover is provided on the cylinder body to cover the enclosed electronic compartment inside.

[0018] The protective cover isolates the sensor's electrical interface from the external environment, preventing metal shavings, cooling water, or oil from entering.

[0019] As a further embodiment of this utility model, it also includes an elastic element, a hydraulic cylinder, and a cylinder cover plate. The cylinder cover plate is disposed at the output end of the hydraulic cylinder, the elastic element is clamped between the cylinder body and the piston body, the cylinder body cooperates with the cylinder body of the hydraulic cylinder, and the piston body and the cylinder cover plate are in contact connection.

[0020] The elastic element is used to force the piston body to remain in contact with the cylinder head body during the lifting and lowering of the hydraulic cylinder, ensuring that the piston body always follows and detects the stroke of the hydraulic cylinder. Through the passive contact of the piston body, no mechanical connection is required between the piston body and the cylinder head body, which facilitates disassembly and maintenance and reduces the disturbance of the hydraulic cylinder to the piston body.

[0021] As a further embodiment of this utility model: an arc-shaped top cover that contacts each other is provided between the piston body and the cylinder head plate.

[0022] If planar contact is used, the two planar ends may not fit properly due to deformation of the mechanism, leading to detection errors. Using arc-shaped surface contact can significantly reduce the contact area while still ensuring an interface for displacement detection.

[0023] As a further embodiment of this utility model, it also includes a fixed wedge block, one side of which is fixedly connected to the cylinder body of the hydraulic cylinder. A recessed groove is formed on the cylinder body, and the cylinder body cooperates with the fixed wedge block through the recessed groove.

[0024] The fixed wedge and recessed groove limit fit structure realizes the precise positioning of the cylinder body on the hydraulic cylinder and axial and radial constraints, preventing the sensor from rotating or loosening due to vibration or oil pressure impact.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows: The detection device adopts a built-in magnetostrictive displacement sensor, which realizes the built-in stroke detection sensor of HGC hydraulic cylinder, avoiding the sensor being directly exposed to harsh environments. At the same time, the non-contact and high-precision detection of the magnetostrictive displacement sensor improves the stability and service life of the hydraulic cylinder stroke detection system. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0027] Figure 1 This is one of the overall structural schematic diagrams of the stroke detection device for the HGC hydraulic cylinder of the rolling mill; Figure 2 This is the second schematic diagram of the overall structure of the stroke detection device for the HGC hydraulic cylinder of the rolling mill.

[0028] In the diagram: 1. Cylinder body; 11. Recessed groove; 2. Piston body; 21. Bracket; 3. Magnetostrictive displacement sensor; 31. Detection rod; 32. Magnetic ring; 33. Electronic compartment; 34. Protective cover; 41. Elastic element; 42. Spring seat; 5. Hydraulic cylinder; 6. Cylinder cover plate; 7. Arc-shaped top cover; 8. Fixing wedge block. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0030] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0031] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0032] Please see Figure 1 As shown in the embodiment of this utility model, a stroke detection device for an HGC hydraulic cylinder of a rolling mill includes a cylinder body 1, a piston body 2, and a magnetostrictive displacement sensor 3. The piston body 2 has a stroke that moves within the cylinder body 1. The magnetostrictive displacement sensor 3 is disposed inside the space enclosed by the cylinder body 1 and the piston body 2.

[0033] Cylinder 1, as a fixed-end structure, serves as a support and sealing protection. Piston 2 is located inside cylinder 1 and can slide axially back and forth in cylinder 1, moving synchronously with the output end of hydraulic cylinder 5. Magnetostrictive displacement sensor 3 is installed in the sealed space formed by cylinder 1 and piston 2, in a safe environment isolated from oil or air. When hydraulic cylinder 5 drives the roller to rise and fall, piston 2 moves synchronously with the cylinder cover plate 6 at the output end of hydraulic cylinder 5. The movement of piston 2 is mechanically transmitted to the magnetostrictive displacement sensor 3 installed inside, achieving displacement sensing through magnetic field interaction.

[0034] The magnetostrictive displacement sensor 3 internally includes a detection rod 31 and a magnetic ring 32. A current pulse is generated by an excitation pulse circuit, amplified, and applied to a waveguide wire (magnetostrictive material) within the detection rod 31. As the excitation pulse propagates through the waveguide wire, it generates a rotating magnetic field around the wire. Simultaneously, the magnetic ring 32 also generates a transverse magnetic field. When the two magnetic fields intersect, a magnetostrictive effect occurs (the dimensions of the magnetostrictive material undergo a slight change, generating a strain pulse magnetic field), propagating in a spiral shape to both sides. The strain pulse wave is attenuated and absorbed by a damper at one end, while the other end is transmitted to an induction coil, converting it into an electrical signal. The time interval between the transmitted and received electrical pulses, along with the known propagation speed, can be obtained through the receiving circuit, allowing the calculation of the displacement change of the target object. Because the position of the magnetic ring 32 is perfectly synchronized with the movement stroke of the piston 2, the displacement measured by the sensor is the real-time stroke of the hydraulic cylinder output.

[0035] In one specific embodiment, the magnetostrictive displacement sensor 3 has the following specific model: GLK1-L0120-CMB33, with a range of 120mm, SSI output, and a resolution of 0.5μmm.

[0036] Furthermore, the detection device of this application consists of three parts: a magnetostrictive displacement sensor 3, a matching cylinder 1, and a piston 2. The magnetostrictive displacement sensor 3 is much smaller and lighter than the magnetic grating displacement sensor, and simplifies the sensor's installation, greatly reducing the inspection load and maintenance costs. In addition, the spare parts cost of the magnetostrictive displacement sensor 3 is only about 20% of that of the Sony magnetic grating displacement sensor, and the processor of the magnetic grating sensor is also eliminated, reducing the cost of matching spare parts and repairs.

[0037] Since the detection rod 31 and the magnetic ring 32 are encapsulated in the internal space of the cylinder 1 and the piston 2, forming a closed protective cavity, the cooling water, steam, oil mist and metal particles in the harsh environment at the bottom of the rolling mill are effectively isolated, avoiding signal distortion and shortened lifespan caused by direct exposure of external sensors.

[0038] The HGC hydraulic cylinder includes a cylinder body (cylinder 5), a piston rod (cylinder 5), and a cylinder head plate (cylinder head plate 6). The cylinder head plate 6 is located at the end of the piston rod and moves synchronously with the piston rod. The cylinder body 1 is mounted on the cylinder body of the hydraulic cylinder 5, and the piston body 2 moves synchronously with the cylinder head plate 6.

[0039] In one embodiment, the piston body 2 and the cylinder head plate 6 are detachably connected by mechanical components. As the cylinder head plate 6 rises and falls, it actively drives the piston body 2 to move synchronously, thereby providing a displacement signal to the magnetostrictive displacement sensor 3. This transmission method does not require an additional elastic element 41 to compress the piston body 2, but additional stress is easily generated between the hydraulic cylinder 5, the cylinder body 1, and the piston body 2, leading to uneven wear of the mechanism and even affecting the detection accuracy.

[0040] In one embodiment, the elastic element 41 is clamped between the cylinder body 1 and the piston body 2, and the piston body 2 and the cylinder head plate 6 are connected by a contact connection without mechanical parts. When the piston rod of the hydraulic cylinder 5 moves up and down, the cylinder head plate 6 moves with the piston rod. The elastic element 41 applies a thrust in the pre-tightened state, causing the piston body 2 to continuously adhere to the cylinder head plate 6. Since the contact is passive, the piston body 2 does not require mechanical locking or rigid connection, and can synchronously follow the actual stroke of the hydraulic cylinder 5 under the action of elastic force, and transmit this stroke to the magnetostrictive displacement sensor 3.

[0041] Because there is no rigid connection between the piston body 2 and the cylinder head plate 6, the hydraulic cylinder 5 will not directly transmit vibrations or pressure pulsations from inside the hydraulic system to the magnetostrictive displacement sensor 3 when it moves. This flexible contact significantly reduces the force disturbance on the sensor, improving detection stability and accuracy.

[0042] A bracket 21 is provided between the magnetic ring 32 and the piston body 2. The bracket 21, through structural connection or constraint, ensures that the magnetic ring 32 maintains a constant spatial relationship with the piston body 2, preventing the magnetic ring 32 from drifting. The fixing function of the bracket 21 ensures that the movement trajectory of the magnetic ring 32 strictly corresponds to the linear displacement of the piston body 2, realizing a one-to-one correspondence between the sensor output signal and the actual displacement of the hydraulic cylinder 5.

[0043] Specifically, the support 21 is a columnar structure extending from the inner wall of the piston body 2 towards the cylinder body 1, with a hollow cavity formed inside the extension. The detection rod 31 extends into the cavity of the support 21. In this structure, the magnetic ring 32 is installed at the end of the support 21 and moves as a whole with the piston body 2. When the piston body 2 pushes the hollow support 21 to slide along the detection rod 31, a relative displacement occurs between the magnetic ring 32 and the detection rod 31, allowing the sensor to achieve non-contact magnetic coupling detection and output the stroke signal of the hydraulic cylinder 5.

[0044] Furthermore, the hollow structure of the bracket 21 encloses the detection rod 31, providing axial guidance and constraint to ensure that the magnetic ring 32 moves straight and stably along the movement path of the detection rod 31, preventing the magnetic ring 32 from skewing or the magnetic field signal from becoming inaccurate. Simultaneously, the hollow enclosing structure forms a physical protective layer for the detection rod 31, effectively blocking the intrusion of external impurities such as oil, dust, and metal shavings, reducing the risk of contamination or scratches to the detection rod 31. This protective structure is particularly suitable for high-temperature, high-pressure, and vibration environments such as rolling mills, improving the reliability of the sensor under harsh operating conditions.

[0045] In one specific embodiment, the elastic element 41 is a spring and is movably sleeved on the periphery of the bracket 21. The long rod-shaped structure of the bracket 21 provides radial constraint for the spring, enhancing the stability of the spring's extension and contraction.

[0046] Further, please refer to Figure 2 As shown, the inner sidewall of the piston body 2 extends radially inward to form a spring seat 42. The spring seat 42 serves as a transition structure between the support 21 and the piston body 2, and the elastic element 41 is clamped between the cylinder body 1 and the spring seat 42. By setting the spring seat 42, the spring mounting position extends inward into the piston body 2. This shortens the overall structural length of the elastic element 41 without affecting the elastic stroke, so that the elastic element 41 does not have to be the same length as the stroke of the hydraulic cylinder 5 or the length of the detection device. With a reduced spring length, the stiffness and compression stability are higher, avoiding eccentric instability of the long spring during compression.

[0047] The detection rod 31 is fixedly connected to a sealed electronic chamber 33 after passing through the cylinder 1. The electronic chamber 33 is connected to the end of the outer shell of the detection rod 31 and to the cylinder 1 via a flange. The detection rod 31 contains a waveguide wire. When the magnetic ring 32 moves with the piston 2, the waveguide wire generates a stress wave signal. This signal is transmitted along the detection rod 31 and is read and output by the sensing circuit at the electronic chamber 33 at the outer end of the detection rod 31. Therefore, the detection rod 31 extends to the outside through the cylinder 1, and the electronic chamber 33 realizes the transmission of electrical signals from the internal detection signal to the external control system. The end of the outer shell of the detection rod 31 and the electronic chamber 33 are fixedly connected by a flange structure. Sealing gaskets or O-rings can be installed between the flange faces to form a reliable sealing surface. This structure can prevent external debris from leaking through the penetration of the detection rod 31, ensuring the system's sealing safety; at the same time, the flange connection facilitates the disassembly and replacement of the sensor unit, allowing maintenance without damaging the main structure of the cylinder 1.

[0048] The cylinder body 1 is equipped with a protective cover 34 that encloses the sealed electronic compartment 33. The protective cover 34 forms a physical isolation layer by completely enclosing the electronic compartment 33 inside the cover, preventing direct contact between external contaminants and the electrical interface. The protective cover 34 can be made of metal or heat-resistant and corrosion-resistant materials, and can withstand high-temperature splashes, mechanical vibrations, and liquid washing.

[0049] During HGC operation in the rolling mill, the cylinder head plate 6 and piston body 2 are exposed to high pressure, high temperature, and strong impact vibration, inevitably causing slight elastic deformation or eccentric displacement of the structural components. If planar end-face contact is used, when either component deforms, end-face warping, local suspension, or contact gaps can easily occur between the two planes, leading to unstable contact surfaces and affecting the accuracy of piston body 2 position detection. This unstable contact can cause slight errors in the sensor's detection stroke or even signal jumps.

[0050] By using a circular arc top cover 7 to form a contact relationship between arc surfaces or between an arc surface and a plane, the contact point can be automatically adjusted according to the slight displacement of the structure. Even if the cylinder 1 or piston 2 undergoes a slight displacement after being subjected to force, the circular arc surface can still maintain single-point or small-area contact, avoiding complete loss of contact. The self-centering characteristic of the circular arc geometry ensures that there is always a contact point between the two parts, guaranteeing that the displacement of the piston 2 can be continuously and accurately transmitted to the detection mechanism.

[0051] The cylinder body 1 and the cylinder body of the hydraulic cylinder 5 are connected by a fixed wedge 8. The fixed wedge 8 and the recessed groove 11 of the cylinder body 1 form a mechanical limiting pair with surface contact or line contact. Through wedge interference or fitting positioning, it provides damping and constraint for the axial movement and radial rotation of the cylinder body 1 in terms of structure.

[0052] In one embodiment, the fixing wedge 8 is a single-sided open enclosure structure. One side is fixed to the cylinder body of the hydraulic cylinder 5 by bolts, and the open side is wedged into the recessed groove 11 on the cylinder body 1 in the radial direction. The enclosure structure can generate slight deformation through the opening to clamp the cylinder body 1, or achieve pressure adjustment by tightening bolts, so that the cylinder body 1 is not easy to loosen after being positioned.

[0053] In one embodiment, a pair of symmetrically arranged fixed wedges 8 are provided on the cylinder body of the hydraulic cylinder 5, which cooperate with two corresponding recessed grooves 11 on the cylinder body 1. The symmetrical wedges form bidirectional radial clamping and self-centering positioning, achieving high-precision fixation of the center of the cylinder body 1.

[0054] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A stroke detection device for an HGC hydraulic cylinder of a rolling mill, characterized in that, include: Cylinder block (1); Piston body (2), the piston body (2) having a stroke that moves within cylinder (1); A magnetostrictive displacement sensor (3) is disposed inside the space enclosed by the cylinder (1) and the piston (2). The magnetostrictive displacement sensor (3) includes a detection rod (31) and a magnetic ring (32). The magnetic ring (32) is movably sleeved around the detection rod (31). The detection rod (31) is disposed on the bottom inner wall of the cylinder (1). A bracket (21) is disposed between the magnetic ring (32) and the piston (2). The bracket (21) is a columnar structure that extends from the inner wall of the piston (2) toward the cylinder (1) and forms a cavity inside the extension. The magnetic ring (32) is disposed at the end of the bracket (21). The detection rod (31) extends into the inner cavity of the bracket (21). An elastic element (41) is clamped between the cylinder (1) and the piston (2). The elastic element (41) is a spring and is movably sleeved on the periphery of the bracket (21). The inner sidewall of the piston (2) extends radially inward to form a spring seat (42). The spring seat (42) serves as a transition structure between the bracket (21) and the piston (2). The elastic element (41) is clamped between the cylinder (1) and the spring seat (42). Hydraulic cylinder (5) and cylinder cover plate (6), the cylinder cover plate (6) is located at the output end of hydraulic cylinder (5), the cylinder body (1) is in cooperation with the cylinder body of hydraulic cylinder (5), the piston body (2) is in contact with the cylinder cover plate (6), and there are arc top covers (7) in contact between the piston body (2) and the cylinder cover plate (6). A fixed wedge (8) is fixedly connected to the cylinder body of the hydraulic cylinder (5) on one side. A recessed groove (11) is formed on the cylinder body (1) and the cylinder body (1) cooperates with the fixed wedge (8) through the recessed groove (11).

2. The stroke detection device for an HGC hydraulic cylinder of a rolling mill according to claim 1, characterized in that, The detection rod (31) is fixed through the cylinder (1) and connected to a closed electronic compartment (33). The end of the electronic compartment (33) is connected to the cylinder (1) through a flange.

3. The stroke detection device for an HGC hydraulic cylinder of a rolling mill according to claim 2, characterized in that, The cylinder body (1) is provided with a protective cover (34) that covers the electronic compartment (33) inside.

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