Multi-roll rolling mill with split front door and method of operating same

Abstract

The present invention relates to a multi-roll rolling mill with a split front door, which includes a rolling mill frame. A working roll set and an intermediate roll set are arranged on the rolling mill frame. A front door is provided on the operating side of the rolling mill. The front door includes an upper front door and a lower front door. The upper front door and the lower front door are respectively movably installed on the rolling mill frame so that both can be opened and closed. An operating side roll shifting drive device is provided on both the upper front door and the lower front door. In addition, it also relates to an operating method of the multi-roll rolling mill. In the present invention, the front door is designed as a split upper front door and lower front door, and an operating side roll shifting drive device is respectively provided on the upper front door and the lower front door. The weight of a single door body is relatively light, effectively reducing the difficulty of opening and closing, and reducing the labor intensity of operators; without integrating a small door on the front door while facilitating the opening and closing of the door body for roll changing, the front door has a simple structure and high sealing reliability; roll changing equipment such as a roll changing cart can directly drive to the front door, ensuring roll changing efficiency, roll changing reliability and roll changing safety.

Description

Technical Field

[0001] The invention belongs to the technical field of rolling mills, and in particular relates to a multi-roller rolling mill with a split front door and an operating method thereof. Background Art

[0002] At present, the production of metal strips is developing towards high strength, low thickness, high precision, high speed and high output. Multi-roll mills have been continuously developed and improved in recent years due to their small working roll diameter, large rolling mill rigidity, small size and light weight, and have been widely used in the field of high-precision and ultra-thin strip steel. In order to obtain a good strip shape and improve the rolling yield rate, in addition to adopting a reasonable rolling process, multi-roll mills also have certain roll shape adjustment means; among them, the stringing of working rolls or intermediate rolls, that is, driving the working rolls or intermediate rolls to move relative to each other perpendicular to the running direction of the strip, can continuously adjust the roll crown, thereby adjusting the roll gap shape to keep it consistent with the cross-sectional shape of the rolled strip, and can also even out the wear of the working rolls or intermediate rolls. Conventional stringing roller drive methods are divided into push-pull type and push-push type. The push-pull type only requires a fixed drive device on one side of the operating side or the transmission side, while the push-push type requires a set of drive devices to be fixed on the operating side and the transmission side respectively. On the other hand, the working rolls and small-diameter intermediate rolls often need to be replaced from the operating side due to their high speed and fast wear.

[0003] For the conventional method of setting the string roll drive device on the operating side, the front door of the multi-roll mill is divided into two types:

[0004] (1) One is that the roller drive device is fixed on the front door, and the front door is directly opened and closed every time the working roller or the intermediate roller is changed; because the front door is relatively heavy, the labor intensity of the operator is high;

[0005] (2) Another method is to separately set up a small door with an integrated roller drive device, which is hinged on the front door. Each time the working roller or intermediate roller is replaced, only the small door needs to be opened and closed. Although the small door is much lighter than the front door, the two sets of roller drive devices are opened and closed together with the small door, and the labor intensity of the operator is still relatively high. In actual production, the intermediate roller balancing device needs to be disassembled and installed before replacing the intermediate roller, and it can only be operated when the front door is open. Therefore, each time the intermediate roller is replaced, the front door still needs to be opened and closed directly, and the labor intensity of the operator is still very high. In addition, when a small door is set on the front door, it is necessary to achieve sealing between the small door and the front door, and between the front door and the rolling mill frame. The sealing is difficult, and problems such as emulsion leakage and excessive steam overflow are prone to occur during normal production of the rolling mill.

[0006] Chinese Patent Application CN114054503A discloses a multi-roll rolling mill with a multi-functional front door. A split upper tandem roll drive module, a middle small door, and a lower tandem roll drive module cooperate to open and close the roll-changing window on the front door. The upper tandem roll drive module, the middle small door, and the lower tandem roll drive module can move separately, which can improve the flexibility of roll-changing operation of the rolling mill and the maintenance efficiency of the rolling mill. However, in practical applications, since the upper tandem roll drive module and the lower tandem roll drive module adopt a lifting and closing form, the sealing effect on the roll-changing window is poor, and problems such as emulsion leakage and excessive steam overflow are likely to occur during the normal production of the rolling mill. Moreover, due to problems such as site restrictions, the descending stroke of the lower tandem roll drive module is also limited. If space needs to be vacated for the roll-changing car, a pit needs to be dug in the foundation below, which is not convenient for equipment layout and on-site management. In addition, it uses three parts to open and close the roll-changing window, which not only increases the sealing difficulty of the roll-changing window, but also affects the convenience of on-site roll-changing operations. Summary of the Invention

[0007] The present invention relates to a multi-roll rolling mill with a split front door and an operation method thereof, which can at least solve some defects of the prior art.

[0008] The present invention relates to a multi-roll rolling mill with a split front door, including a rolling mill frame. A work roll set and an intermediate roll set are arranged on the rolling mill frame. A front door is provided on the operation side of the rolling mill. The front door includes an upper front door and a lower front door. The upper front door and the lower front door are respectively movably installed on the rolling mill frame so that both can be opened and closed. Operation side tandem roll drive devices are provided on both the upper front door and the lower front door.

[0009] As one of the embodiments, the upper edge of the lower front door is not higher than the bottom end of the lower work roll.

[0010] As one of the embodiments, a roll-changing support plate is provided at the top of the operation side tandem roll drive device on the lower front door.

[0011] As one of the embodiments, both the upper front door and the lower front door are hinged to the rolling mill frame.

[0012] As one of the embodiments, an upper front door locking mechanism and a lower front door locking mechanism are provided on the rolling mill frame.

[0013] As one of the embodiments, the upper front door locking mechanism and / or the lower front door locking mechanism includes a locking bolt and a locking drive unit for driving the locking bolt to move. Corresponding locking bolt holes are provided on the corresponding door bodies to cooperate with the locking bolt.

[0014] As one of the embodiments, the operation side tandem roll drive device uses a hydraulic cylinder.

[0015] As one of the implementation manners, two groups of drive-side roll shifting drive devices are provided on the drive side of the rolling mill, and the operator-side roll shifting drive device and the drive-side roll shifting drive device constitute a push-push type roll shifting system.

[0016] The present invention also relates to an operation method of the above multi-roll rolling mill, including:

[0017] When the upper intermediate roll needs to be replaced, open the upper front door to open the required roll changing window;

[0018] When the lower intermediate roll needs to be replaced, open the lower front door to open the required roll changing window;

[0019] When the working roll needs to be replaced, open the door body blocking the working roll to be replaced to open the required roll changing window.

[0020] As one of the implementation manners, when replacing the working roll and / or the upper intermediate roll, the operator-side roll shifting drive device on the lower front door is used as a roll changing bracket to assist in completing the operation of the roll body entering and exiting the rolling mill.

[0021] The present invention has at least the following beneficial effects:

[0022] The present invention designs the front door as a split upper front door and lower front door, and an operator-side roll shifting drive device is respectively arranged on the upper front door and the lower front door. The weight of a single door body is relatively light, effectively reducing the difficulty of opening and closing, and reducing the labor intensity of the operator. When it is convenient to open and close the door body for roll changing, no small door is integrated on the front door, and the front door structure is simple and the sealing reliability is high; roll changing equipment such as a roll changing vehicle can directly drive to the front door, which can ensure the roll changing efficiency, roll changing reliability and roll changing safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0024] Figure 1 It is a schematic diagram when both the upper front door and the lower front door provided in Embodiment 1 of the present invention are closed;

[0025] Figure 2 It is a schematic diagram when the upper front door provided in Embodiment 1 of the present invention is opened;

[0026] Figure 3 It is a schematic diagram when the lower front door provided in Embodiment 1 of the present invention is opened;

[0027] Figures 4 - 6Schematic diagram of the structures of three string roll control systems provided in Embodiment 2 of the present invention. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment 1

[0030] As Figures 1 - 3 , an embodiment of the present invention provides a multi-roll rolling mill with a split front door, which includes a rolling mill frame 1. A working roll group 11 and an intermediate roll group are arranged on the rolling mill frame 1. A front door is provided on the operating side of the rolling mill. The front door includes an upper front door 21 and a lower front door 22. The upper front door 21 and the lower front door 22 are respectively movably installed on the rolling mill frame 1 so that both can be opened and closed. Operating side string roll driving devices 31 are provided on both the upper front door 21 and the lower front door 22.

[0031] Among them, the structure of the rolling mill frame 1 and the arrangement structures of the working roll group 11 and the intermediate roll group on the rolling mill frame 1 are all conventional technologies in the art and will not be elaborated here. Generally, the working roll group 11 includes two working rolls distributed on both sides of the rolling line above and below; the intermediate roll group includes an upper intermediate roll group 12 and a lower intermediate roll group 13 distributed on both sides of the rolling line above and below.

[0032] The above-mentioned operating side string roll driving device 31 can adopt commonly used string roll driving devices in the art, including but not limited to hydraulic cylinders, air cylinders, electric push rods, etc.; in this embodiment, it is preferably a hydraulic cylinder.

[0033] In addition, preferably, two groups of drive side string roll driving devices 32 are provided on the drive side of the rolling mill. One group of drive side string roll driving devices 32 is opposite to one group of operating side string roll driving devices 31, and the other group of drive side string roll driving devices 32 is opposite to the other group of operating side string roll driving devices 31; each operating side string roll driving device 31 and the corresponding drive side string roll driving device 32 constitute a push-push type string roll system.

[0034] In one of the embodiments, as Figures 1 - 3, the upper front door 21 and the lower front door 22 are both hinged to the rolling mill stand 1, and the axial direction of the hinge shaft is parallel to the vertical direction. The swing-type door body is adopted, and the sealing performance is good, which can effectively reduce the situation of emulsified liquid and steam splashing out during the operation of the rolling mill. Among them, the hinge points of the two can be located on the same side, that is, the upper front door 21 and the lower front door 22 open towards the same side, which is convenient for the configuration of the space required for the rotation of the door body and can reduce the space required for the operation of the rolling mill to a certain extent.

[0035] Among them, the opening and closing of the upper front door 21 and the lower front door 22 can be completed manually or through automatic equipment, and any driving equipment capable of realizing the automatic opening and closing of the swing door is applicable to this embodiment.

[0036] Further, an upper front door 21 locking mechanism and a lower front door 22 locking mechanism (shown in the figure but not labeled) are provided on the rolling mill stand 1. In one embodiment, the upper front door 21 locking mechanism and / or the lower front door 22 locking mechanism includes a locking bolt and a locking driving unit for driving the locking bolt to move, and a locking pin hole cooperating with the locking bolt is correspondingly provided on the corresponding door body.

[0037] In one embodiment, the lower side operating side cluster roll driving device 31 can act as a roll changing bracket to assist in completing the roll changing operation, which can improve the roll changing efficiency and ensure the safety and reliability of roll changing; correspondingly, a roll changing support plate is provided at the top of the operating side cluster roll driving device 31 on the lower front door 22. Further, the above roll changing support plate can be detachably installed on the operating side cluster roll driving device 31 or movably arranged on the operating side cluster roll driving device 31, for example, hinged and driven by a cylinder / hydraulic cylinder, etc., to realize the up and down swing of the roll changing support plate, which can reduce the interference with equipment such as the lower side operating side cluster roll driving device 31.

[0038] In one embodiment, the upper edge of the lower front door 22 is flush with the steel passing line. The upper side operating side cluster roll driving device 31 can apply a pushing / pulling force to the upper work roll and / or the upper intermediate roll group 12, and the lower side operating side cluster roll driving device 31 can apply a pushing / pulling force to the lower work roll and / or the lower intermediate roll group 13; when the upper front door 21 is opened, it is convenient for the upper work roll and the upper intermediate roll group 12 to enter and exit; when the lower front door 22 is opened, it is convenient for the lower work roll and the lower intermediate roll group 13 to enter and exit.

[0039] In other embodiments, such as Figure 1 and Figure 2, the upper edge of the lower front door 22 is not higher than the bottom end of the lower working roll. In this scheme, the upper operating side roller drive device 31 can apply a push / pull force to the working roll group 11 and / or the upper intermediate roll group 12, and the lower operating side roller drive device 31 can apply a push / pull force to the lower intermediate roll group 13; when the upper front door 21 is opened, it is convenient for the working roll group 11 and the upper intermediate roll group 12 to enter and exit; when the lower front door 22 is opened, it is convenient for the lower intermediate roll group 13 to enter and exit. In this scheme, the door gap between the upper front door 21 and the lower front door 22 avoids the area of the working roll group 11 where the emulsion splashes more seriously, so the overflow of the emulsion can be effectively reduced. In the above scheme of making the operating side roller drive device 31 act as a roll changing bracket, when the upper edge of the lower front door 22 is designed to be not higher than the bottom end of the lower working roll, the lower operating side roller drive device 31 can assist in completing the roll changing operation of the working roll group 11 and the upper intermediate roll group 12, and the application effect is better.

[0040] Wherein, preferably, the lower edge of the upper front door 21 and the upper edge of the lower front door 22 are respectively provided with sealing parts. When the upper front door 21 and the lower front door 22 are both closed, the sealing parts of the two can cooperate to block the door gap between the upper front door 21 and the lower front door 22, thereby improving the sealing of the front door and reducing the escape of emulsion and steam. In one embodiment, a first sealing plate is formed downwardly at the bottom end of the upper front door 21, and a second sealing plate is formed upwardly at the top end of the lower front door 22. When the upper front door 21 and the lower front door 22 are both closed, the first sealing plate and the second sealing plate are fitted together front and back to achieve the purpose of sealing; since the first sealing plate and the second sealing plate are both soft plates, they will not interfere with the opening and closing of the upper front door 21 and the lower front door 22. In another embodiment, a first sealing pad is provided at the bottom end of the upper front door 21, and a second sealing pad is provided at the top end of the lower front door 22. When the upper front door 21 and the lower front door 22 are both closed, the first sealing pad and the second sealing pad are pressed against each other to achieve the purpose of sealing.

[0041] Preferably, the multi-roll rolling mill is a twenty-roll rolling mill.

[0042] The embodiment of the present invention also relates to an operating method of the multi-roll mill, comprising:

[0043] When the upper intermediate roller needs to be replaced, the upper front door 21 is opened to open the required roller replacement window;

[0044] When the lower intermediate roller needs to be replaced, the lower front door 22 is opened to open the required roller replacement window;

[0045] When the working roll needs to be replaced, the door body covering the working roll to be replaced is opened to open the required roll changing window.

[0046] Among them, for the case where the upper edge of the lower front door 22 is flush with the wire passing through, when replacing the upper working roll, open the upper front door 21; when replacing the lower working roll, open the lower front door 22; for the case where the upper edge of the lower front door 22 is not higher than the bottom end of the lower working roll, when replacing the working roll, open the upper front door 21.

[0047] Furthermore, when replacing the working roll and / or the upper intermediate roll, use the roll shifting drive device 31 on the operating side of the lower front door 22 as a roll changing bracket to assist in the operation of the roll body entering and exiting the rolling mill.

[0048] Embodiment 2

[0049] The embodiment of the present invention provides a roll shifting control system, which can be used in the first embodiment above as a push-push type roll shifting system therein.

[0050] Such as Figures 4 - 6 , the roll shifting control system includes a roll shifting hydraulic cylinder 31 on the operating side, a roll shifting hydraulic cylinder 32 on the drive side, and a first valve control unit 33.

[0051] (1) In one embodiment, such as Figures 4 - 6 , the rodless cavity of the roll shifting hydraulic cylinder 31 on the operating side is connected in series with the rodless cavity of the roll shifting hydraulic cylinder 32 on the drive side through a relay oil pipe. The rodless cavities of the roll shifting hydraulic cylinder 31 on the operating side and the roll shifting hydraulic cylinder 32 on the drive side are both connected to the first valve control unit 33. The first valve control unit 33 is used to control the connection of the rodless cavity of the roll shifting hydraulic cylinder 31 on the operating side with the oil inlet pipeline and the connection of the rodless cavity of the roll shifting hydraulic cylinder 32 on the drive side with the oil return pipeline, or to control the connection of the rodless cavity of the roll shifting hydraulic cylinder 31 on the operating side with the oil return pipeline and the connection of the rodless cavity of the roll shifting hydraulic cylinder 32 on the drive side with the oil inlet pipeline.

[0052] (2) In another embodiment, the rodless cavity of the roll shifting hydraulic cylinder 31 on the operating side is connected in series with the rodless cavity of the roll shifting hydraulic cylinder 32 on the drive side through a relay oil pipe. The rod cavities of the roll shifting hydraulic cylinder 31 on the operating side and the roll shifting hydraulic cylinder 32 on the drive side are both connected to the first valve control unit 33. The first valve control unit 33 is used to control the connection of the rod cavity of the roll shifting hydraulic cylinder 31 on the operating side with the oil inlet pipeline and the connection of the rod cavity of the roll shifting hydraulic cylinder 32 on the drive side with the oil return pipeline, or to control the connection of the rod cavity of the roll shifting hydraulic cylinder 31 on the operating side with the oil return pipeline and the connection of the rod cavity of the roll shifting hydraulic cylinder 32 on the drive side with the oil inlet pipeline.

[0053] Preferably, the first method above is adopted, and accordingly, a push-push roll shifting method is formed.

[0054] In one embodiment, such as Figures 4 - 6, the first valve control unit 33 described above includes a three-position four-way valve. The oil inlet pipeline and the oil return pipeline are connected to two of the oil ports of the three-position four-way valve, and two string rollers hydraulic cylinders are connected to the other two oil ports of the three-position four-way valve. The three-position four-way valve is preferably a solenoid valve.

[0055] Among them, preferably, the first valve control unit 33 described above uses a servo valve. Using a servo valve, especially a precision servo valve, can effectively improve the accuracy and reliability of the string roller operation.

[0056] The string roller control system provided in this embodiment connects the rodless chambers or rod chambers of the operating side string roller hydraulic cylinder 31 and the driving side string roller hydraulic cylinder 32 in series, which can make the operating side string roller hydraulic cylinder 31 and the driving side string roller hydraulic cylinder 32 move interlocked, realize servo action, and improve the reliability of the string roller control. Compared with the traditional scheme, this scheme can reduce the number of precision servo valves, thereby saving equipment investment and maintenance costs, and reducing the labor intensity of operators.

[0057] Further preferably, as Figures 4 - 6 , both groups of hydraulic cylinders are equipped with return oil pipes. The return oil pipes are connected to the rodless chambers and rod chambers of the corresponding hydraulic cylinders, and the return oil pipes are equipped with a second valve control unit; when the relay oil pipe connects two rod chambers in series, the return direction controlled by the second valve control unit is from the rodless chamber to the rod chamber; when the relay oil pipe connects two rodless chambers in series, the return direction controlled by the second valve control unit is from the rod chamber to the rodless chamber. Based on the above scheme, the string roller control accuracy and reliability can be effectively improved. Specifically:

[0058] Due to the limitation of manufacturing level, it is extremely difficult to ensure that the cylinder diameters of the operating side string roller hydraulic cylinder 31 and the driving side string roller hydraulic cylinder 32 are exactly the same. Even if the operating side string roller hydraulic cylinder 31 and the driving side string roller hydraulic cylinder 32 are of the same type, there are still errors in the cylinder diameters of the two groups of hydraulic cylinders; and based on the above scheme, through the hydraulic oil return control of the corresponding side hydraulic cylinders, the manufacturing error compensation of the same-level cavities of the two groups of hydraulic cylinders can be realized, thereby improving the string roller control accuracy and reliability.

[0059] In one of the embodiments, both the operating side string roller hydraulic cylinder 31 and the driving side string roller hydraulic cylinder 32 are equipped with a displacement detection unit for detecting the displacement of their piston rods. The displacement detection unit includes but is not limited to using a linear displacement sensor.

[0060] Furthermore, by cooperating the displacement detection unit with the above-mentioned second valve control unit, the effect of precisely controlling the return flow of hydraulic oil can be achieved. Among them, the displacement detection unit and the above-mentioned second valve control unit are both electrically connected to the central control room. By detecting whether the displacement of the piston rods of the two groups of hydraulic cylinders is the same through the displacement detection unit, when the displacements of the two piston rods are the same, the return operation of the hydraulic oil is stopped, that is, the second valve control unit is closed.

[0061] In one embodiment, as Figure 4 , the two return oil pipes are independent of each other, and the second valve control unit is respectively provided on the two return oil pipes. Preferably, as Figure 4 , the second valve control unit adopts a two-position two-way solenoid valve 341.

[0062] In another embodiment, if the two return oil pipes share a set of second valve control units, the number of valves can be further reduced.

[0063] Optionally, as Figure 5 , the second valve control unit includes a two-position three-way solenoid valve 342. The two-position three-way solenoid valve 342 has one inlet and two outlets. Both return oil pipes include a first pipe section and a second pipe section, and the inlet ends of the return oil pipes are located on the first pipe sections. Both first pipe sections are connected to the inlet of the two-position three-way solenoid valve 342, and the two second pipe sections are respectively connected to the two outlets of the two-position three-way solenoid valve 342. In this structure, check valves can be provided on the two first pipe sections, and the direction allowed by the check valves is the direction flowing into the inlet of the two-position three-way solenoid valve, which can prevent the two first pipe sections from cross-flowing.

[0064] Optionally, as Figure 6 , the second valve control unit includes a three-position four-way solenoid valve 343. One of the return oil pipes is connected to one of the inlets and one of the outlets of the three-position four-way solenoid valve 343, and the other return oil pipe is connected to the other inlet and the other outlet of the three-position four-way solenoid valve 343.

[0065] The above second valve control unit only needs to adopt an ordinary solenoid valve to obtain a good control effect, without the need to adopt a servo valve, and the cost is relatively low.

[0066] Based on the above implementation of the string roll control system, the following string roll control method can be implemented:

[0067] The first valve control unit 33 is used to control the oil inlet of the string roll hydraulic cylinder on the corresponding side. The two groups of string roll hydraulic cylinders perform corresponding actions under the action of hydraulic oil, so that the corresponding roll body 10 moves toward the target side.

[0068] Taking the relay oil pipe connecting the rodless cavities of the string roll hydraulic cylinder 31 on the operation side and the rodless cavity of the string roll hydraulic cylinder 32 on the drive side in series as an example:

[0069] a. After the hydraulic oil flows through the first valve control unit 33, it flows into the rodless cavity of the operation-side roll-shifting hydraulic cylinder 31, pushing the piston rod of the operation-side roll-shifting hydraulic cylinder 31 to move. Then, the hydraulic oil in the rod cavity of the operation-side roll-shifting hydraulic cylinder 31 is pushed into the rod cavity of the drive-side roll-shifting hydraulic cylinder 32, causing the piston rod of the drive-side roll-shifting hydraulic cylinder 32 to be pushed. Subsequently, the hydraulic oil in the rodless cavity of the drive-side roll-shifting hydraulic cylinder 32 is pushed to flow back to the hydraulic station through the first valve control unit 33. In this case, the roll body 10 moves towards the drive side;

[0070] Further, when the first valve control unit 33 is powered on, the second valve control unit is also powered on, conducting the rodless cavity and the rod cavity of the drive-side roll-shifting hydraulic cylinder 12. Then, the hydraulic oil in the rodless cavity of the drive-side roll-shifting hydraulic cylinder 12 will flow back to its rod cavity until the piston rod displacement of the two hydraulic cylinders is equal. After the piston rod displacement of the hydraulic cylinder reaches the position, the first valve control unit 33 is powered off, and the second valve control unit is also powered off.

[0071] b. After the hydraulic oil flows through the first valve control unit 33, it flows into the rodless cavity of the drive-side roll-shifting hydraulic cylinder 32, pushing the piston rod of the drive-side roll-shifting hydraulic cylinder 32 to move. Then, the hydraulic oil in the rod cavity of the drive-side roll-shifting hydraulic cylinder 32 is pushed into the rod cavity of the operation-side roll-shifting hydraulic cylinder 31, causing the piston rod of the operation-side roll-shifting hydraulic cylinder 31 to be pushed. Subsequently, the hydraulic oil in the rodless cavity of the operation-side roll-shifting hydraulic cylinder 31 is pushed to flow back to the hydraulic station through the first valve control unit 33. In this case, the roll body 10 moves towards the operation side;

[0072] Further, when the first valve control unit 33 is powered on, the second valve control unit is also powered on, conducting the rodless cavity and the rod cavity of the operation-side roll-shifting hydraulic cylinder 11. Then, the hydraulic oil in the rodless cavity of the operation-side roll-shifting hydraulic cylinder 11 will flow back to its rod cavity until the piston rod displacement of the two hydraulic cylinders is equal. After the piston rod displacement of the hydraulic cylinder reaches the position, the first valve control unit 33 is powered off, and the second valve control unit is also powered off.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-roll rolling mill with a split front door, comprising a rolling mill frame, on which a working roll set and an intermediate roll set are arranged, and a front door is provided on the operating side of the rolling mill, characterized in that: The front door includes an upper front door and a lower front door. The upper front door and the lower front door are respectively movably installed on the rolling mill frame so that both can be opened and closed. An operating side pinion roll driving device is provided on both the upper front door and the lower front door; The upper edge of the lower front door is not higher than the bottom end of the lower working roll; An upper front door locking mechanism and a lower front door locking mechanism are provided on the rolling mill frame.

2. The multi-roll rolling mill with a split front door as claimed in claim 1, characterized in that: A roll changing support plate is provided at the top of the operating side pinion roll driving device on the lower front door.

3. The multi-roll rolling mill with a split front door as described in claim 1, characterized in that: Both the upper front door and the lower front door are hingedly installed on the rolling mill frame.

4. The multi-roll rolling mill with a split front door according to claim 1, characterized in that: The upper front door locking mechanism and / or the lower front door locking mechanism includes a locking bolt and a locking driving unit for driving the locking bolt to move. A locking pin hole cooperating with the locking bolt is correspondingly provided on the corresponding door body.

5. The multi-roll rolling mill with a split front door as claimed in claim 1, characterized in that: The operating side pinion roll driving device uses a hydraulic cylinder.

6. The multi-roll rolling mill with a split front door as described in claim 1, characterized in that: Two groups of driving side pinion roll driving devices are provided on the driving side of the rolling mill. The operating side pinion roll driving device and the driving side pinion roll driving device constitute a push-push type pinion roll system.

7. The operating method of the multi-roll rolling mill according to any one of claims 1 to 6, characterized in that, Including: When the upper intermediate roll needs to be replaced, open the upper front door to open the required roll changing window; When the lower intermediate roll needs to be replaced, open the lower front door to open the required roll changing window; When the working roll needs to be replaced, open the door body covering the working roll to be replaced to open the required roll changing window.

8. The operating method according to claim 7, characterized in that: When replacing the working roll and / or the upper intermediate roll, use the operating side pinion roll driving device on the lower front door as a roll changing support bracket to assist in completing the operation of the roll body entering and leaving the rolling mill.

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