JP3273312B2 - Hydraulic rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic rolling mill capable of reducing a horizontal or vertical roll while rolling metal, for example.

[0002]

2. Description of the Related Art FIG. 5 is an elevational view showing a main part of a conventional double rolling mill having two upper and lower rolls. In the drawing, the reduction of a roll incorporated in a rolling mill body 1 is performed by a reduction device 3 that operates an upper roll chock 2 with an electric screw.
It is done by adjusting up and down with. Adjustment of the pass line is performed by inserting the liner 5 below the lower roll chock 4. Therefore, the height of the lower roll is adjusted stepwise, and the intermediate pass line with the upper roll does not always have a constant height, and is not vertically symmetrically reduced. Rolling mill body 1 of the conventional double rolling mill as described above
As shown in FIG. 6, the screw 3 fixed to the screw down of the upper roll chock 2 rotates the worm wheel 8 with the worm 9 to move up and down with respect to the fixed screw 7. This makes it possible to adjust the rolling reduction. In such a scheme,
The reaction force during rolling is self-blocked in the screw-down device 3, and the screw-down reaction force is not transmitted to the worm 9 or the screw-down handle. In addition, the right and left screw down devices 3 which are mechanical manual screw downs are:
As shown in FIG. 7, they are connected by a joint shaft 10.

[0003] The conventional screw-down device operated by an electric screw is configured as described above, and the pass line adjustment for inserting the liner 5 below the lower roll chock 4 and the screw-down adjustment of the upper roll chock 2 by the screw-down device 3 are performed. It is impossible to adjust during rolling, and pass line adjustment and rolling reduction due to roll wear and the like have to be performed during the gap time between billet and billet or during rolling stop, and recently commercialization Continuous rolling, with increasing momentum
That is, there is a problem that it is not possible to improve efficiency by connecting the billet ends and continuously supplying the end of the billet to perform endless rolling.

[0004]

In order to solve the above-mentioned problems of the screw-down device operated by the electric screw in recent years, a hydraulic cylinder operated by oil or water and the like is used, and the output of the hydraulic cylinder is kept constant. Lower devices are being developed. Further, a method of precisely controlling the gap between the rolling rolls by controlling the position of a hydraulic cylinder and a reduction ram by a servo valve has been adopted.

[0005] However, in the constant pressure lowering device for maintaining the output of the hydraulic cylinder constant as described above, the hydraulic pressure generated by the hydraulic pump is adjusted by the pressure reducing valve to control the rolling force. Therefore, although the thrust of the hydraulic cylinder is constant, there is a problem that the roll interval changes due to the fluctuation of the rolling load and the mill constant becomes zero.

[0006] Further, in a drafting device for controlling the roll gap by controlling the position of a hydraulic cylinder and a drafting ram by means of a servo valve, good control characteristics are obtained, the mill constant can be easily changed, and in the case of overload. It has the features that it becomes a safety device by releasing hydraulic pressure, but also has the following disadvantages. In other words, the energy efficiency is extremely poor,
The resulting energy loss causes the temperature of the hydraulic oil in the storage tank to rise, which requires forced cooling in a cooler to lower the temperature. Will be reduced. Further, although the response of the servo valve is good, there is a problem that the adjustment of the device is extremely difficult, and the adjustment work takes time.

[0007]

SUMMARY OF THE INVENTION A hydraulic rolling mill according to the present invention has been made in order to solve the above-mentioned problems, and has a two-way discharge fixed displacement or variable displacement directly connected to an electric motor. A capacity hydraulic pump, a single-rod double-acting hydraulic cylinder driven directly by the hydraulic pump, a circuit that absorbs the difference in liquid volume between the head side and the rod side during cylinder operation, and stores compressible gas and hydraulic fluid. Equipped with a closed tank and a linear scale that detects displacement of the cylinder rod,
A hybrid actuator comprising a controller that drives the electric motor by feeding back the displacement information of the linear scale and comparing the input information with the input position command is provided.

[0008] The hydraulic rolling mill according to the present invention comprises:
The hybrid actuator is provided on each of both shaft portions of a roll, and the both shafts of the roll are synchronously reduced.

Further, the hybrid actuator is provided on each of both shaft portions of the roll, and the both shafts of the roll are synchronously raised.

Further, the hybrid actuator is provided on each of both shaft portions of the upper roll and both shaft portions of the lower roll, so that the synchronous pressure is simultaneously raised and lowered.

Further, the present invention is characterized in that the pressure of the hybrid actuator is controlled to be lowered synchronously or raised synchronously.

Further, the present invention is characterized in that a synchronous pressure is lowered or a synchronous pressure is raised while controlling the pressure and displacement of the hybrid actuator.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing a hydraulic rolling mill according to an embodiment of the present invention. In the figure, 2
0 is a drive source integrated type hydraulic actuator (hybrid
Actuators) are provided on the left and right sides of the upper roll chock 2 and the lower roll chock 4 of the rolling mill main body 1, and are formed so as to be capable of rolling down during rolling.
As shown in the enlarged views of FIGS. 2 and 3, the pressing device 20 incorporates a single rod type pressing cylinder 11 fixed to the rolling mill main body 1. The rolling cylinder 1
1 is a two-way discharge type pump 12 directly connected to a servomotor 13 for supplying oil as a pressure medium to a pressure reduction cylinder 11, which is formed integrally with an oil tank 14 via a manifold 15.
The connection between the pump and the pump 12 and the connection between the reduction cylinder 11 and the oil tank 14 are made by pipes housed in the manifold 15, so that no external piping is required, so that the size and weight are reduced, and the rolling is performed in an integrated state. It can be easily attached to and detached from the machine body 1, maintenance work is extremely simple, and the number of assembly steps is drastically reduced.

The oil tank 14 is of a closed type in order to protect the pressure reduction cylinder 11 from a bad environment in which dust, cooling water, steam and the like are present. To prevent this, a certain amount of air or other compressible gas is sealed inside. The volume ratio of hydraulic oil to gas is better if the ratio of gas is larger,
On the other hand, if the hydraulic oil is extremely reduced, the gas filled together with the hydraulic oil is sucked from the hydraulic circuit, so that when the cylinder rod 21 is protruded to the stroke end, the pressure becomes the minimum pressure (1 bar), and the stroke end is reduced. A ratio that is less than 2 bar when retracted to the maximum is desirable. In addition, since the rolling device 20 of the present application is used horizontally and can be installed in any direction, it is not limited to the rolling device from the upper part of the rolling mill, but also to the rolling device from the lower part. It can be mounted simply by changing its orientation. At this time, the oil tank 14 and the pump 12
Is set at the center, and the oil level is set higher than the center of the oil tank 14. Note that a stroke sensor 16 is provided in the screw-down cylinder 11.
The stroke is detected with an accuracy of 1/100, and the servo motor 13 is controlled by this signal, so that the four left, right, upper and lower cylinders can be completely synchronized. Therefore, a completely symmetrical vertical reduction is possible.

FIG. 4 is a system diagram showing a drive circuit of the hydraulic rolling mill according to the embodiment of the present invention. In the figure,
31 is an adder a, 32 is an adder b, 33 is a servo amplifier, 34 is a shuttle valve, and 35 is a pressure sensor. The control input signal Ei generated by the operator is converted by the adder a and the adder b, and when the control input signal Ei is input to the servo amplifier 33, the servo motor 13 operates and the pump 12
The lowering cylinder 11 operates by the operation of, and the lowering roll is applied to the upper and lower rolls via the roll chocks 2 and 4. The adjustment of the rolling reduction is performed by the feedback signal fd of the displacement from the stroke sensor 16 and the pressure sensor 35.
Is controlled by two levels of the pressure feedback signal fp from the controller. The shuttle valve 34 adjusts the difference in volume change between the rod-side and the head-side cylinder chambers because the pressure reduction cylinder 11 is a single rod cylinder.

In the hydraulic rolling mill constructed as described above, the pump 12 rotates in the rotation direction of the servo motor 13 directly connected without passing through a direction control valve, a liquid amount control valve, a pressure control valve, or a servo valve. By controlling the rotation speed and the torque, the discharge direction, the liquid amount and the liquid pressure are controlled to drive the screw down cylinder 11 to directly control the moving direction, speed and thrust of the rod. By doing so, the servomotor 13 and the pump 12 are almost stopped when the pressing cylinder 11 is pressurizing but the position of the cylinder rod 21 is kept constant even during rolling. Energy consumption will drop sharply. Only a small amount of power is consumed when changing the roll gap, and the noise is drastically reduced as the energy consumption is reduced. The fluctuation of the roll gap is also detected by the stroke sensor 16 directly connected to the cylinder rod 21 and the change is detected by the adder a.
31 and the fluctuation can be quickly corrected. The rolling device 20 is an upper roll chock 2,
Lower roll chock 4 can be rolled down during rolling.
Since 0 is operable in synchronization and performs vertical symmetric rolling, the pass line between the upper and lower rolls can always be kept at a constant height. Further, the amount of reduction can be finely adjusted, and the reduction device can be operated for reduction in an arbitrary predetermined period. Further, since the apparatus itself is compact, the stand base, the shift apparatus, and the like of the rolling mill can have the same shape and the same dimensions as those of the related art. Table 1 is a specification example of a rolling mill to which the present invention is applied.

[0017]

[Table 1]

In the above embodiment, the present invention has been described with reference to an example of a double rolling mill. However, the present invention is not limited to the above embodiment, but may be a quadruple rolling mill or a rolling mill having a vertical axis. It can be applied regardless of the type of rolling mill, the rolling method, the material of the material to be rolled, the product shape, and the like. Further, although the shuttle valve is used to adjust the difference in volume change between the cylinder chambers on the rod side and the head side of the pressure reduction cylinder, other circuits such as a pilot check valve and a relief valve may be applied. Further, the servomotor only needs to be able to detect the thrust (or hydraulic pressure) and displacement of the screw-down cylinder and control the rotation direction, speed and torque of the motor by feedback control, and a general-purpose motor may be used. Further, the pump uses a bi-directional fixed displacement pump or a bi-directional variable displacement pump, and changes the rotation direction of the input shaft to perform bi-directional discharge, or the rotation direction of the input shaft is fixed and the discharge direction is set at the pump side. For example, a bidirectional variable displacement pump of the hydrostatic transmission (HST) type is adopted, and the rotation direction of the input shaft is constant, and the tilt angle of the swash plate is controlled from the normal rotation angle to the reverse rotation angle to thereby control the rotation. The discharge direction may be changed. Further, the pressure medium is not limited to oil, and may be another liquid such as water containing a rust preventive.

[0019]

As described above, according to the present invention, the rolling device in which each roll chock can be rolled down can be rolled down during rolling, so that the roll rolling can be adjusted during rolling.
The pass line between the rolls can always be kept at a constant height. Further, since the amount of reduction can be finely adjusted, the dimensional accuracy of the rolled product can be improved. Further, the rolling-down device can perform a rolling-down operation in an arbitrary period set in advance, and for example, can correct a roll rolling-down amount during continuous rolling.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a hydraulic rolling mill according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a hydraulic rolling mill according to an embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a hydraulic rolling mill according to the embodiment of the present invention.

FIG. 4 is a system diagram showing a drive circuit of the hydraulic rolling mill according to the embodiment of the present invention.

FIG. 5 is an elevation view showing a configuration of a main part of a conventional double rolling mill.

FIG. 6 is a cross-sectional view showing a conventional rolling device of a double rolling mill.

FIG. 7 is an explanatory view showing a connecting portion of a conventional reduction device of a double rolling mill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling machine main body 2 Upper roll chock 4 Lower roll chock 11 Lower cylinder 12 Pump 13 Servo motor 14 Oil tank 15 Manifold 16 Stroke sensor 17 Lower mouse 20 Lowering device 21 Cylinder rod 31 Adder a 32 Adder b 33 Servo amplifier 34 Shuttle valve 35 Pressure sensor

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Sato 1031-18 Osaw, Fujisawa-shi, Kanagawa (56) References JP-A-9-136105 (JP, A) JP-A-8-206713 (JP, A) JP-A-8-155523 (JP, A) JP-A-8-108204 (JP, A) JP-A-6-114426 (JP, A) JP-A-61-88309 (JP, A) JP-A-7-308704 ( JP, A) JP-A-5-248405 (JP, A) JP-A-52-138464 (JP, A) JP-A-49-115055 (JP, A) JP-A-52-37599 (JP, A) JP JP-A-10-169602 (JP, A) JP-A-9-88906 (JP, A) JP-A-8-326705 (JP, A) JP-A-1-312203 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B21B 31/32 B21B 37/00 B21B 37/62 F15B 11/08

Claims (6)

(57) [Claims] 1. A two-way discharge fixed displacement or variable displacement hydraulic pump directly connected to an electric motor, a single rod double-acting hydraulic cylinder driven directly by a hydraulic pump, and a head side and a rod side during cylinder operation. A circuit that absorbs the difference in liquid volume, a closed tank that stores compressible gas and hydraulic fluid, and a linear scale that detects displacement of the cylinder rod,
A hydraulic rolling mill comprising a hybrid actuator configured by a controller that drives a motor by feeding back displacement information of a linear scale and comparing it with an input position command. 2. The hydraulic rolling mill according to claim 1, wherein the hybrid actuator is provided on each of both shaft portions of the roll, and the both shafts of the roll are synchronously reduced. 3. The hydraulic rolling mill according to claim 1, wherein the hybrid actuator is provided on each of the two shaft portions of the roll, and both shafts of the roll are synchronously raised. 4. The hybrid actuator according to claim 1, wherein said hybrid actuator is provided on each of both shafts of an upper roll and both shafts of a lower roll.
A contractor characterized by synchronously raising simultaneously with synchronous lowering
The hydraulic rolling mill according to claim 1 . 5. The hydraulic rolling mill according to claim 2, wherein the pressure of the hybrid actuator is controlled to increase or decrease synchronously. 6. The hydraulic rolling mill according to claim 2, wherein the hydraulic pressure is increased or decreased synchronously while controlling the pressure and displacement of the hybrid actuator.