JPH0214123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic reduction device for a rolling mill in which an intermediate cylinder is incorporated in a hydraulic control section.

The hydraulic rolling device of the conventional general rolling mill, 4H
This will be explained with reference to FIG. 1, which is applied to a mill. It has upper and lower work rolls 1 and 2 as rolling rolls, and upper and lower reinforcing rolls 3 and 4 that press these from the outside, respectively,
The metal strip 5 is rolled between the work rolls 1 and 2. A reduction jack 7A for pressurizing the rolling roll is installed below the lower reinforcing roll 4, and includes a reduction ram 6 held in a cylinder 7. This reduction jack 7A includes a control valve 8 that controls the oil pressure in the cylinder 7, a control panel 9 that drives this control 8, and a position detection device that detects the position of, for example, the reduction ram 6 and feeds back the detection signal to the control panel 9. A control device consisting of a device 10 and the like is connected.

The operation of such a hydraulic lowering device is performed as follows. That is, the position command 11 is amplified by the control panel 9 to drive the control valve 8. Then, by the operation of the control valve 8, the oil is switched from the pump port 12 to the control valve 8 to the cylinder 7, or from the cylinder 7 to the control valve 8 to the tank port 12, thereby raising and lowering the compression ram 6. Reduction ram 6
The position is fed back to the control panel 9 by the position detector 10, thereby forming a position servo system.

However, in this conventional hydraulic rolling down device, since it is necessary to attach the position detector 10 to the rolling down ram 6, the structure of the rolling jack 7A becomes complicated and expensive, and the rolling scale and cooling water do not reach the position detector 10. It is difficult to maintain because it adheres to the rolls, and when changing the rolls, it is usually necessary to lower the reduction ram 6 to the lowest end, but in order to maintain this state, the position servo system is turned off. However, there were disadvantages such as a lot of effort was required for adjustment during subsequent recovery operations, and the work efficiency was correspondingly low.

Incidentally, a device shown in FIG. 2 has recently been considered as a device capable of overcoming the above-mentioned drawbacks.

That is, an intermediate cylinder 14 is provided between the main jack 7A, which is the first reduction jack, and a control valve 8 that controls the oil pressure in the cylinder 7 of the main jack 7A.
One oil chamber 14A formed by A is connected to the cylinder 7 of the main jack 7A, and the other oil chamber 14B is connected to the main jack 7A.
are connected to the control valve 8, and a detector for detecting the rolling state, for example, a position detector 10 of the reduction ram 6, is provided on the piston rod 15 of the intermediate cylinder 14 to drive the control valve 8.
According to such a configuration, the above-mentioned drawbacks can be overcome by allowing the position detector 10 to be placed apart from the main jack 7A.

However, in the case of such a device, the actual situation is that the diameter of the intermediate cylinder 14 is generally much smaller than the diameter of the main jack 7A in consideration of installation space and the like. In this case, intermediate cylinder 1
It is difficult to compensate for the small diameter of the piston rod 4 by increasing the total stroke of the piston rod 15 due to cost and space considerations. Port 12 or tank port 13
A bypass path 16A is provided over the area, and the stroke of the reduction ram 6 is covered by a switching valve 16 attached to the bypass path 16A.

Then, when operating the switching valve 16, especially when the reduction ram 6 is lowered, the oil pressure _Pc in one oil chamber 14A of the intermediate cylinder 14 becomes almost zero, and therefore, in order to stop the piston rod 15, the position servo system is required. had to be turned off in the same manner as above, and the drawback could not be resolved.

Furthermore, by providing the intermediate cylinder 14, sliding resistance due to the seal etc. of the piston 15A is added, increasing the total resistance, resulting in a problem that the response is lower than that shown in Fig. 1. .

The present invention was made in view of such information, and there is no need to turn off the position servo system, etc.
Therefore, it is an object of the present invention to provide a hydraulic rolling-down device for a rolling mill, which can be operated smoothly regardless of roll rearrangement, etc., and has improved responsiveness compared to the prior art.

A feature of the present invention for achieving this object is that the piston rod of the intermediate cylinder is provided with a balancing spring means for counteracting the force exerted on the piston rod by the rolling load.

An embodiment of the present invention will be described below with reference to FIG.

It should be noted that the same components as those of the prior art described above are given the same reference numerals as those in FIG. 1 or 2, and the explanation thereof will be omitted.

As a spring means, a balance cylinder device 17A
has been established. This balance cylinder device 17A
is composed of a cylinder 17 whose axis is arranged on an extension line of the axis of the intermediate cylinder 7A, and a piston rod 18 inserted into this cylinder 17, and the piston rod 18 is connected to the intermediate cylinder 147A.
The piston rod 15 is connected to the piston rod 15 via a joint 19. A position detector 10 for the reduction ram 6 is attached to this balance cylinder device 17A. And this balance cylinder device 17A cylinder 1
One oil chamber formed by the piston 18A at 7, that is, the oil chamber 17B facing the intermediate cylinder 7A.
The pump port 12 is connected to the pump port 12 via a pressure control valve 20. That is, a balance pressure P _B in the direction in which the reduction ram 6 opens is applied to the oil chamber 17B, and this balance pressure P _B is maintained at a predetermined value by the pressure control valve 20.

With such a configuration, for example, the bypass path 1
Even when the switching valve 16 of 6A operates in the roll opening direction, due to the action of the balance pressure P _B , the pressure P' _c in the oil chamber 14B on the side opposite to the main jack of the intermediate cylinder 14 is approximately equal to the balance pressure P _B. is maintained, the differential pressure across the control valve 8 in the roll opening and closing directions,
In other words, the difference between the pump pressure and the internal pressure of the oil chamber 14B is P _s - P′ _c
does not become zero, and the difference P′ _c −P _t between the internal pressure of the oil chamber 14B and the pressure on the tank port 13 side also does not become zero.
Therefore, there is no need to turn off the position servo system, and the position servo system can be kept in the on state at all times. As a result, roll rearrangement, etc. can be performed with the position servo system "on", and there is no need for troublesome restoration work, etc., as in the past.

Moreover, according to such a configuration, the pressure P _{′ c} normally applied to the oil chamber 14B on the side opposite to the main jack of the intermediate cylinder 14 by the control valve 8 is made constant in response to the balance pressure P _B of the balance cylinder device 17A. As shown in Figure 2, unlike the case where the pressure P' _c of the same part fluctuates, it becomes possible to respond sharply even to minute pressure commands.
Responsiveness can also be improved.

In the above embodiment, a type in which one intermediate cylinder was provided for each main jack on either the drive side or the operation side was described, but the present invention is not limited to such a type; 4
As shown in the figure, both main jacks may be controlled by one intermediate cylinder.

That is, the intermediate cylinder 14 is a synchronized intermediate cylinder that is provided with a pair of oil chambers 14A adjacent to each other in the axial direction, corresponding to the cylinders 7 of the main jacks 7A on the drive side and operation side of the rolling mill. A balance cylinder device 17A having the function of an oil spring is connected to the piston rod 15 of this intermediate cylinder 14, as in the previous embodiment.

According to such a configuration, by using one control valve 8, control panel 9, and position detector 10, it is possible to simultaneously raise and lower the reduction rams 6 installed on the drive side and the operation side. Note that it is desirable to provide a switching valve 21 for stroke correction between the intermediate cylinder 14 and the pump port 12 and tank port 13 so as to enable left-right adjustment. Further, the balance pressure P _B needs to be about twice as strong as that of the above embodiment.

In addition, in each of the above embodiments, the balance cylinder device 17A is provided separately from the intermediate cylinder 14, but the balance cylinder can be configured integrally with the intermediate cylinder. For example, although not shown,
A pressure chamber may be provided at one end of the intermediate cylinder, and the piston rod of this intermediate cylinder may operate as a balance piston within this pressure chamber.

Furthermore, in the embodiment described above, a balance cylinder for an oil spring was used as the spring device, but the present invention is not limited to this, and other spring means such as a pneumatic spring or a metal spring may be used.

Furthermore, in the above embodiment, a position detector is used as a rolling state detector, and a position servo system control means formed by the position detector is shown. Needless to say, it is also possible to use a pressure gauge or the like as a control means for a load or pressure servo system.

As described in detail in the above embodiments, the present invention eliminates the need to turn off the servo system due to the effect of balance pressure even when changing rolls or opening rolls, and therefore the operation is easy. In addition to greatly improving performance, high responsiveness can be achieved, and the desired purpose can be achieved.

[Brief explanation of drawings]

1 and 2 are block diagrams showing different conventional devices, FIG. 3 is a block diagram showing one embodiment of the present invention, and FIG. 4 is a block diagram showing another embodiment of the present invention. 6... Reduction ram, 7... Cylinder, 7A... Main jack, 8... Control valve, 14... Intermediate cylinder, 14A, 14B... Hydraulic chamber, 10... Detector, 15... Piston rod, 17... ...spring means (balance cylinder device).

Claims (1)

[Scope of Claims] 1. An intermediate cylinder is provided between a hydraulic main jack having a cylinder holding a reduction ram for pressurizing a rolling roll and a control valve that controls the hydraulic pressure in the cylinder of this main jack, One oil chamber of this intermediate cylinder is connected to the cylinder of the main jack, and the other oil chamber is connected to the control valve, and a rolling state detection detector is provided on the piston rod of this intermediate cylinder to control the control valve. 1. A hydraulic rolling mill drive device, characterized in that the piston rod of the intermediate cylinder is provided with a balancing spring means for counteracting the force with which the piston rod is pressed by the rolling load. 2. The hydraulic rolling-down device for a rolling mill according to claim 1, wherein the spring means is a balance cylinder device having a hydraulic oil spring function. 3. The intermediate cylinder is a synchronized intermediate cylinder equipped with a pair of oil chambers corresponding to the cylinders of the main jacks on the driving side and operating side of the rolling mill, and one spring means is attached to the common piston rod of the synchronized intermediate cylinder. 3. A hydraulic rolling-down device for a rolling mill according to claim 1 or 2, wherein the main jacks on the drive side and the operation side are commonly controlled by providing the main jack.