JP2001259737A - Overload prevention apparatus of roller leveler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overload prevention apparatus to detect excessive reaction force to a backup roll and to prevent the backup roll from being damaged. SOLUTION: The apparatus consists of a pressure transducer 61 and a pressure switch 62 to detect a pressure of extended side oil chambers 12a, 3a of a crowning cylinder 12 and a reduction cylinder 3, a directional control valve 32, based on the detected signals of the pressure transducer 61/pressure switch 62, which drains a hydraulic oil of the extended side oil chambers 12a, 3a of the crowning cylinder 12/reduction cylinder 3, and a relief valve 56 connected to an oil passage supplying the hydraulic oil to the extended side oil chambers 12a, 3a of the crowning cylinder 12/reduction cylinder 3, the detected pressure of the pressure transducer 61/pressure switch 62 are set to a first setting value P1 meaning an abnormal load, the relief valve 56 is set to open at a second value P2 lower than the first setting value P1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing an overload of a roller leveler. More specifically, the present invention relates to an overload prevention for preventing a backup roll from being damaged in a roller leveler for straightening a metal sheet and a strip.

[0002]

2. Description of the Related Art As a conventional example of a crowning device of a roller leveler, there is a wedge type described in Japanese Patent Publication No. 56-41323, but in this conventional example, the correction amount cannot be changed locally. Since adjustment after biting of the plate cannot be performed, it is impossible to set an optimum amount of reduction over the entire length of the plate.

The inventor of the present invention has disclosed, for example, Japanese Patent Application Laid-Open No. H11-123457 and Japanese Patent Application No. Hei.
No. 1-139541 (not disclosed) proposes a roller leveler. The roller leveler includes a plurality of crowning cylinders mounted in the width direction between the upper roll frame and the upper frame, an upper straightening roll supported by the upper roll frame, and an upper backup roll supporting the same. When the tip of the plate to be corrected enters between the upper and lower straightening rolls, the individual hydraulic crowning cylinders are tightened so that the appropriate amount of reduction can be corrected over the entire width of the plate.

[0004]

However, in the above-mentioned conventional example, an excessive reaction force may be applied to a specific backup roll due to an incorrect setting of the rolling reduction or an excessive crowning setting. It has occurred. Therefore, an object of the present invention is to provide an overload prevention device that detects an excessive reaction force on a backup roll and prevents breakage of the backup roll.

[0005]

According to a first aspect of the present invention, there is provided an overload preventing device for a roller leveler, comprising: an upper frame; a pressing cylinder for pressing down the upper frame; an upper roll frame suspended from the upper frame; A plurality of crowning cylinders mounted in the width direction between the upper roll frame and the upper frame, an upper straightening roll supported by the upper roll frame, an upper backup roll thereof, a lower frame, and a lower frame; In the roller leveler provided with the lower roll frame installed in the lower roll frame and the lower straightening roll supported by the lower roll frame and the lower backup roll, an overload prevention mechanism is attached to the crowning cylinder to prevent the overload. A pressure transducer for detecting a pressure in an oil chamber on an extension side of the crowning cylinder, and a pressure; A switch, a control valve for discharging hydraulic oil in the extension-side oil chamber of the crowning cylinder based on a detection signal of the pressure transducer or the pressure switch, and an oil passage for supplying hydraulic oil to the extension-side oil chamber of the crowning cylinder. Consisting of a connected relief valve,
The detection pressure of the pressure transducer and the pressure switch is set to a first set value meaning an abnormal load, and the opening of the relief valve is set to a second set value lower than the first set value. Features. An overload prevention device for a roller leveler according to claim 2, wherein the upper frame, a pressing cylinder for pressing down the upper frame, an upper roll frame suspended from the upper frame, and the upper roll frame and the upper frame. In between, a plurality of crowning cylinders mounted in the width direction, an upper straightening roll supported by the upper roll frame, an upper backup roll thereof, a lower frame, and a lower roll frame installed on the lower frame, In a roller leveler provided with a lower straightening roll supported by the lower roll frame and a backup roll below the lower straightening roll, an overload prevention mechanism is attached to the reduction cylinder, and the overload prevention mechanism is provided on the extension side of the reduction cylinder. A pressure transducer and a pressure switch for detecting oil chamber pressure, and the pressure transducer or pressure; A control valve for discharging hydraulic oil in the extension-side oil chamber of the pressure-reducing cylinder based on a detection signal of the switch, and a relief valve connected to an oil passage for supplying hydraulic oil to the extension-side oil chamber of the pressure-reduction cylinder, The detection pressure of the pressure transducer and the pressure switch is set to a first set value meaning an abnormal load, and the opening of the relief valve is set to a second set value lower than the first set value. Features. According to a third aspect of the present invention, there is provided an overload prevention device for a roller leveler, wherein an overload prevention mechanism attached to a crowning cylinder according to the first aspect and an overload prevention mechanism attached to a pressure reduction cylinder according to the second aspect are combined. Features.

According to the first aspect of the present invention, since the relief valve is opened and the pressure is released before the abnormal pressure is generated in the crowning cylinder, this function prevents the roller leveler from being overloaded. Even if an abnormal pressure occurs, the pressure transducer or the pressure switch detects the abnormal pressure, switches the control valve and discharges the operating oil from the crowning cylinder, so that the abnormal load is instantly eliminated. Therefore, accidents such as breakage of the backup roll can be prevented beforehand by the double safety measures. According to the second aspect of the present invention, since the relief valve is opened and the pressure is released before the abnormal pressure is generated in the screw-down cylinder, this function prevents the roller leveler from being overloaded. Further, even if an abnormal pressure occurs, the pressure transducer or the pressure switch detects the abnormal pressure, switches the control valve, and discharges the hydraulic oil from the pressure-down cylinder, so that the abnormal load is instantly eliminated. Therefore, accidents such as breakage of the backup roll can be prevented beforehand by the double safety measures. According to the third aspect of the present invention, since the pressing force of both the crowning cylinder and the pressing down cylinder can be eliminated, it is possible to prevent a situation in which one pressing force is eliminated and the other pressing force remains, and the overload is prevented. The effect on prevention is higher.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a hydraulic circuit diagram of a crowning cylinder overload prevention device according to one embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram of a rolling cylinder overload prevention device according to one embodiment of the present invention, FIG. 3 is a control block diagram of a crowning cylinder, etc., FIG. 4 is a front view of a main part of a left half of the roller leveler, FIG. 5 is a side view of a main part of the roller leveler, and FIG. .

First, the basic configuration of a roller leveler to which the present invention is applied will be described. As shown in FIGS. 4 and 5, a press-down cylinder 3 is disposed between the upper frame 1 and the housing 2, and an upper roll frame 4 is provided below the upper frame 1.
Are suspended by the upper roll grip cylinder 5.
A plurality of upper straightening rolls 6 are supported on the upper roll frame 4, and a short upper backup roll 7 is attached to each upper straightening roll 6 in an axial direction.

A plurality of lower straightening rolls 8 are arranged on the upper straightening roll 6 with a pass line interposed therebetween, and backup rolls 9 corresponding to the lower straightening rolls 8 are supported by lower roll frames 10, respectively. . The lower roll frame 10 is set on the lower frame 11.

In the roller leveler having the above basic structure, a plurality of hydraulic crowning cylinders 12 are connected between the upper frame 1 and the upper roll frame 4. Each of the crowning cylinders 12 is installed at a substantially equal pitch along the width direction of the upper frame 1 over substantially the same width as the straightening rolls 6 and 8 (see FIG. 4). Two rows are provided (see FIG. 5). The number of rows of the crowning cylinders may be one, but if the number is two, the local lateral deflection of the upper roll frame 4 can be more finely corrected.

As shown in FIG. 6, the crowning cylinder 12 has an upper end of a piston 13 connected to the upper frame 1 via a spherical joint member 14, and a lower end of a cylinder 15 connected to an upper roll frame via a slide joint 16. 4. The crowning cylinder 12 has a built-in position detection sensor 20.

FIG. 3 is a control block diagram of the crowning cylinder 12 and the like. Reference numeral 30 denotes a controller for the crowning cylinder 12, which is constituted by a microcomputer or the like. Reference numeral 31 denotes a flexure detection sensor that detects the flexure of the upper frame 1 and is installed on the press frame above the center position of the upper frame 1. The deflection detection sensor 31 constantly detects the distance X to the lower end of the upper frame 1. By detecting the amount of bending of the upper frame 1, the amount of bending of the upper roll frame 4 can also be detected. Further, the amount of bending of the lower frame 11 can be obtained from the amount of bending of the upper frame 1 by proportional calculation.

Reference numeral 32 denotes a direction control valve interposed in a hydraulic circuit for feeding oil to the extension-side oil chamber of the crowning cylinder 12. Reference numerals 41 to 48 are attached to the pressing cylinder 3, the crowning cylinder 12, the upper roll frame 4, the upper backup roll 7, the upper straightening roll 6, the lower straightening roll 8, the lower backup roll 9, and the lower roll frame 10, and their compression deformation This is a load cell using a strain gauge for detecting a load.

The deflection detecting sensor 31, the pressure switch 3
3. The detection values of the position detection sensor 20 and the strain gauges 41 to 47 are input to the controller 30. In addition, 34 is a line controller, and S is a plate material to be corrected.

The controller 30 keeps track of the amount of deflection of the upper frame 1 and the upper roll frame 4 and the pressure in the cylinder 15 of the crowning cylinder 12 based on the input signals, and adjusts each crowning cylinder necessary to correct the deflection of the frame. The elongation amount of 12, ie, the tightening amount is calculated. Also, a crowning cylinder 12, an upper roll frame 4, an upper backup roll 7, an upper straightening roll 6,
The amount of deformation of the lower straightening roll 8, the lower backup roll 9, and the lower roll frame 10 is constantly grasped, and the extension amount of each crowning cylinder 12, that is, the tightening amount required to correct the deformation is calculated. Then, these two narrowing amounts are summed up, and an output signal is calculated so as to feed pressure oil having a pressure corresponding to the sum. Further, the result is fed back to control so that the bending and the deformation become zero. As a result, an appropriate pressing force is applied to each of the backup rolls 7, 7,.
Thereby, the plate material is corrected with high accuracy.

Next, an overload prevention device applied to the roller leveler will be described with reference to FIGS. FIG. 1 is a hydraulic circuit of an overload prevention mechanism attached to the crowning cylinder 12, and FIG. The overload prevention device of the present invention may be constituted only by the overload prevention mechanism attached to the crowning cylinder 12, or may be constituted solely by the overload prevention mechanism attached to the rolling-down cylinder 3. Preferably, the latter embodiment will be described below. Although a plurality of reduction cylinders 3 and a plurality of crowning cylinders 12 constituting the roller leveler are provided, the overload prevention mechanisms attached to the respective cylinders are substantially the same. An overload prevention mechanism for the crown 3 and the crowning cylinder 12 will be described.

As shown in FIG. 1, a first oil passage 51 is connected to an extension-side oil chamber (also called a head-side oil chamber) 12a of the crowning cylinder 12, and a contraction-side oil chamber (also called a rod-side oil chamber). ) 12b is connected to a second oil passage 52. The ends of the first and second oil passages 51 and 52 communicate with a tank 53. A pump 54 and the direction control valve 32 are interposed in the first oil passage 51, and a pressure transducer 61 and a pressure switch 62 are further connected thereto. The directional control valve 32 is an electrohydraulic servo valve, which stops supply and discharge of hydraulic oil at a neutral position, supplies hydraulic oil to the extension-side oil chamber 12a at an a position to extend the crowning cylinder 12, At the position b, the hydraulic oil is discharged from the extension side oil chamber 12a to contract the crowning cylinder 12. The direction control valve 32 constitutes a control valve referred to in the claims.
In the above hydraulic circuit, 57 is a relief valve, 58
Is a pressure reducing valve. The set pressure of the relief valve 57 is 5
8 is higher than the set pressure. When the crowning cylinder 12 is extended, the hydraulic oil in the rod-side oil chamber 12b passes through the second oil passage 52 and returns to the tank 53 through the relief valve 57. When the crowning cylinder 12 is contracted, the hydraulic oil in the head side oil chamber 12a passes through the first oil passage 51, returns to the tank through the directional control valve 32 at the position b, and returns to the tank.

The pressure transducer 61 and the pressure switch 62 have a first set value P1 indicating an abnormal load.
, And the electro-hydraulic drive unit of the direction control valve 32 is operated by the detection signal to instantaneously switch to the position b.
Thereby, the extension side oil chamber 12a of the crowning cylinder 12
Since the hydraulic oil is discharged from the cylinder and the pressure is instantaneously lost, it is possible to prevent the backup rolls 6 and 8 from being damaged.

A bypass circuit 55 is connected between the first oil passage 51 and the second oil passage 52, and a relief valve 56 is interposed in the bypass circuit 55. This relief valve 56
Is set to a second set value P2 lower than the first set value P1. That is, the alarm load does not reach the abnormal load, but indicates a warning value close to the abnormal load. First oil passage 51
When the pressure in the passage and thus the internal pressure of the extension-side oil chamber 12a of the crowning cylinder 12 reaches the second set value P2, the relief valve 56 is opened to allow hydraulic oil to bypass from the first oil passage 51 to the second oil passage 52. So the crowning cylinder 12
Is suppressed. Therefore, an abnormal load on the backup rolls 6, 8 is prevented in advance.

As shown in FIG. 2, a similar hydraulic circuit is provided in the pressure reduction cylinder 3. Then, similarly to the crowning cylinder 12, the pressure transducer 6
1, the pressure switch 62 is connected, and the direction control valve 32 and the relief valve 56 are connected. Since their functions are the same, the same members are denoted by the same reference numerals and description thereof will be omitted. With the above configuration, the screw-down cylinder 3 is also
When the first set value P1 is reached, the direction control valve 32 is switched to the position b, the hydraulic oil is discharged from the extension-side oil chamber 3a of the reduction cylinder, and the pressing force is lost. Also, the second set value P
When the pressure becomes 2, the relief valve 56 hears and the pressing force of the pressurizing cylinder 3 is released. This can prevent the backup rolls 6, 8 from being damaged.

In this embodiment, normally, the relief valve 5
6, the overload is prevented, but since the relief valve inherently takes time to release the load pressure, a sudden overload occurs as in the case where the thickness of the plate to be corrected suddenly becomes thick. In some cases, a load is generated and the abnormal load cannot be eliminated even when the relief valve 56 is opened. Or relief valve 5
Even if 6 is malfunctioning or has failed, overload cannot be prevented. In such a case, the pressure transducer 61 or the pressure switch 62 operates at the first set value P1 to switch the direction control valve 32 to the position b, so that the pressure of the crowning cylinder 12 and the pressure cylinder 3 is instantaneously released, An abnormal load can be eliminated. As described above, the pressure applied to the backup rolls 6, 8 is reliably eliminated by the double safety measures, and the backup rolls 6, 8
Can be prevented.

In the above embodiment, the pressure transducer 61 and the pressure switch 62 have the same function.
This is a backup in the event that one of the devices fails, thereby improving the degree of security. In addition, since the overload prevention mechanism is provided in both the crowning cylinder 12 and the pressure reduction cylinder 3, even if one of the overload prevention mechanisms fails or malfunctions, the other overload prevention mechanism causes the overload prevention mechanism to operate. Can be prevented, so that safety is improved.

[0023]

According to the first aspect of the present invention, the relieving valve is opened and the pressure is released before an abnormal pressure is generated in the crowning cylinder, so that an overload does not occur on the roller leveler. Even if an abnormal pressure occurs, the pressure transducer or the pressure switch detects the abnormal pressure, switches the control valve and discharges the operating oil from the crowning cylinder, so that the abnormal load is instantly eliminated. Therefore, accidents such as breakage of the backup roll can be prevented beforehand by the double safety measures. According to the second aspect of the present invention, since the relieving valve is opened and the pressure is released before the abnormal pressure is generated in the screw-down cylinder, overload does not occur on the roller leveler. Further, even if an abnormal pressure occurs, the pressure transducer or the pressure switch detects the abnormal pressure, switches the control valve, and discharges the hydraulic oil from the pressure-down cylinder, so that the abnormal load is instantly eliminated. Therefore, accidents such as breakage of the backup roll can be prevented beforehand by the double safety measures. According to the invention of claim 3, since the pressing force of both the crowning cylinder and the pressure-reducing cylinder can be eliminated, it is possible to prevent a situation in which one pressing force is eliminated and the other pressing force remains.
The effect on overload prevention becomes higher.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a crowning cylinder overload prevention device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of an apparatus for preventing an overload of a screw-down cylinder according to an embodiment of the present invention.

FIG. 3 is a control block diagram of a crowning cylinder and the like.

FIG. 4 is a front view of a main part of a left half of a roller leveler.

FIG. 5 is a side view of a main part of the roller leveler.

FIG. 6 is an enlarged side view around the crowning cylinder 12.

[Explanation of symbols]

 3 Lowering Cylinder 6,8 Straightening Roll 12 Crowning Cylinder 32 Direction Control Valve 56 Relief Valve 61 Pressure Transducer 62 Pressure Switch

Claims (3)

[Claims] An upper frame, a pressing cylinder for pressing down the upper frame, an upper roll frame suspended from the upper frame, and a plurality of rolls in a width direction between the upper roll frame and the upper frame. An attached crowning cylinder, an upper straightening roll supported by the upper roll frame, an upper backup roll, a lower frame, a lower roll frame installed on the lower frame, and a lower roll frame supported by the lower roll frame. In a roller leveler provided with a lower straightening roll and a lower backup roll, an overload prevention mechanism is attached to the crowning cylinder, and the overload prevention mechanism detects a pressure of an extension-side oil chamber of the crowning cylinder. A transducer and a pressure switch, and a detection of said pressure transducer or pressure switch. A control valve for discharging hydraulic oil in an extension-side oil chamber of the crowning cylinder based on a signal; and a relief valve connected to an oil passage for supplying hydraulic oil to the extension-side oil chamber of the crowning cylinder, wherein the pressure transformer The detection pressures of the transducer and the pressure switch are set to a first set value indicating an abnormal load, and the opening of the relief valve is set to a second set value lower than the first set value. Roller leveler overload prevention device. 2. An upper frame, a press-down cylinder for pressing down the upper frame, an upper roll frame suspended from the upper frame, and a plurality of rolls in a width direction between the upper roll frame and the upper frame. An attached crowning cylinder, an upper straightening roll supported by the upper roll frame, an upper backup roll, a lower frame, a lower roll frame installed on the lower frame, and a lower roll frame supported by the lower roll frame. In a roller leveler including a lower straightening roll and a lower backup roll, an overload prevention mechanism is attached to the pressing cylinder, and the overload preventing mechanism detects a pressure of an extension-side oil chamber of the pressing cylinder. A transducer and a pressure switch;
A control valve for discharging hydraulic oil from the extension-side oil chamber of the pressure-reducing cylinder based on a detection signal from the pressure transducer or the pressure switch, and an oil passage that supplies hydraulic oil to the extension-side oil chamber of the pressure-reduction cylinder. A relief valve, wherein the detection pressure of the pressure transducer and the pressure switch is set to a first set value meaning an abnormal load, and the opening of the relief valve is set to a second set value lower than the first set value. An overload prevention device for a roller leveler, wherein the device is set. 3. An overload preventive mechanism provided on a crowning cylinder according to claim 1 and an overload preventive mechanism provided on a reduction cylinder according to claim 2 combined. Prevention device.