KR20090049860A - Rolling machine and rolling method - Google Patents

Abstract

A bed, a base installed on the bed and a transfer table slidably installed on the base, spaced apart from the transfer table so that a large amount of rolling is possible by solving the problems caused when the pressure applied to the material is increased. A fixed stage installed on a bed, a pair of rolling dice respectively installed on the transfer table and the fixed base, a driving unit for driving the rolling die, and a pressing unit installed on the bed to apply a transfer pressure to the transfer table; The base or the fixed base fixed to the bed is formed with a projection or groove, the bed provides a rolling device formed with a groove or projection corresponding to the projection or groove.

Bed, Base, Support, Fixture, Protrusion, Groove, Hydraulic Cylinder

Description

Rolling device and rolling method {ROLLING MACHINE AND ROLLING METHOD}

The present invention relates to a rolling device. More specifically, the present invention relates to a rolling apparatus and a rolling method capable of implementing a large capacity.

In general, roll processing involves forming a screw thread by rotating the material while applying a pressure to the surface of the screw material by applying a die that sculpts the thread by inverting the peak and the valley to the same pitch as the screw to be processed. It is a kind of cold working method.

The rolling device for such rolling processing usually includes a bed and a pair of rolling dice installed on the bed and having a working surface. The desired processing is performed by placing the material between the rolling dies and applying a predetermined pressure to rotate the rolling dies.

As described above, the method of forming a thread while applying pressure to the surface of the material using a rolling die can secure productivity and precision compared to a cutting method of cutting a surface of a material using a machine tool to form a thread. This is the preferred trend.

However, as described above, since the pressure-type screw forming structure using the rolling die is difficult to increase the pressure applied to the material, it is difficult to increase the size of the capacity as compared with the screw forming structure of the cutting method. Therefore, the development of a large-capacity rolling machine is required.

Accordingly, the present invention provides a rolling device rolling method capable of rolling a large capacity by solving various problems generated when the pressure applied to the material is increased.

In addition, there is provided a rolling device and a rolling method that can prevent the distortion by making the distribution of the force properly in the rolling process.

In addition, it provides a rolling device and a rolling method that can increase the production through the control of the rotation speed.

In addition, it provides a rolling device and a rolling method that can prevent the occurrence of various accidents by quickly draining the pressure oil after the work is completed.

To this end, the present rolling device is installed on the bed, the base installed on the bed and the transfer table slidably installed on the base, the fixed stand installed on the bed spaced apart from the transfer table, and the transfer stand and the fixed stand, respectively. A pair of rolling dice, a driving part for driving the rolling dice, and a pressing part installed on the bed to apply a feeding pressure to the conveying table, and a protrusion or a groove is formed in the base or the fixing table fixed to the bed. The bed may have a groove or a protrusion corresponding to the protrusion or the groove.

In the installation of the base or the base on the bed, the protrusions or grooves formed on the mutual contact surface is engaged with each other can be more firmly fixed to the base or the base on the bed. Therefore, it is possible to prevent the rod or base from being pushed against the high rolling pressure, and to prevent abrasion and shearing of the fastening bolts fixing the rod or the base to the bed.

The driving unit may include a driving motor connected to the rotating shaft of the rolling die.

The pressing unit may include a support installed on the bed and at least one hydraulic cylinder installed on the support and connected to the transport to push the transport.

In this case, the support may be provided with a protrusion or a groove on a contact surface with the bed, and the bed may have a groove or a protrusion corresponding to the protrusion or the groove.

In addition, the rolling device may include a connection bar that is connected between the fixing and the support to add a bearing force.

In addition, the present rolling device may include an adjusting unit for adjusting the pressure applied to each of the hydraulic cylinders.

In addition, the present rolling apparatus may further include a drain portion for quickly draining the pressure oil in the hydraulic cylinder.

On the other hand, the present rolling method is the step of gradually increasing the rotational speed and the pressing force of the rolling die from the low pressure low pressure in the process of processing the material by pressing the rolling die while pressing the rolling die to the raw material between the rolling die, and the rolling Driving a die at a high speed and high pressure, it may include the step of gradually lowering the speed and pressure of the precursor die.

As such, by increasing the coupling force between the bed and each structure installed on the bed, it is possible to implement a large-capacity rolling device by improving the durability of the structure against the high-pressure operating pressure.

In addition, it is possible to prevent the distortion by adjusting the pressure applied between the hydraulic cylinders.

In addition, it is possible to prevent the equipment accident by quickly reversing the cylinder through a quick pressure oil drain.

In addition, the production speed can be increased through the rotation speed and pressure control of the rolling die.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

It is noted that the figures are schematic and not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same structure, element or part that appears in more than one figure the same reference numerals are used in different embodiments to indicate corresponding or similar features.

1 is a plan view showing a rolling device according to the present embodiment, Figure 2 is a front view showing the rolling device.

As shown, the present rolling device is a bed 20 installed on the frame 10, the base 21 is fixedly installed on the bed 20, the transfer table is slidably installed on the base 21 (22), the holder 23 spaced apart from the conveying table 22 is fixedly installed on the bed (20), rotatably installed in each of the conveying table 22 and the fixing table 23 to form a pair It includes a die 24, a drive unit for driving the rolling die 24, the pressing portion is installed on the bed 20 to apply a transfer pressure to the conveying table (22).

Bearing blocks 25 are respectively provided on the front surfaces of the fixing table 23 and the conveying table 22 so that the rotating shaft of the rolling die 24 is installed through the bearing.

Accordingly, the rolling dice 24 are paired by being installed on the fixed base 23 and the transfer table 22 via the bearing block 25, respectively.

The driving unit includes a driving motor 26 installed at one side of the frame 10 and a power transmission mechanism for transmitting the rotational force of the driving motor 26 to the rotation shaft of the rolling die 24.

In the present embodiment, the power transmission mechanism is a reduction gear 27 installed on the rotation shaft of the drive motor, the universal joint 28 and each universal installed on the output shaft of the reduction gear and the rotation shaft of the rolling die 24, respectively. It includes a flexible pipe 29 for connecting the joint. The expansion pipe 29 is a structure that can be changed in length while transmitting power, for example, the spline is formed on the surface and the spline is formed on the inner peripheral surface may be a coupling structure of the boss is inserted into the shaft.

In addition, the pressing portion is fixed to one side of the bed 20 and the support 30 is installed side by side on the support 30 and connected to the transfer table 22 for moving the transfer table 22 Hydraulic cylinders 31a and 31b.

Accordingly, when the hydraulic cylinders 31a and 31b are extended and operated, the feed table 22 slides with respect to the base 21 to pressurize the material P located between the rolling dice 24, and the driving motor 26 operates. The rolling die 24 is rotated to roll the material (P).

Here, look at the installation structure of each structure installed in the bed 20 and the bed 20 as follows.

2 and 3, the bed 20 is a planar structure, the fixing base 23 and the support 30 are installed at both ends of the bed 20, the base 21 is installed in the center do. And the bed 20 is formed with grooves 40, 41, 42 to a predetermined depth at the position where each member is installed. Reference numeral 43 is a bolt fastening hole to which the bolts 34 for fixing the members to the bed 20 are fastened.

The fixing member 23 and the support member 30 have a flange 32 formed at a lower end thereof, and a bolt through hole 33 is formed at the flange 32. The bolt 34 is fastened to the bed 20 via the medium.

In addition, the fixing member 23 fastened to the bed 20 has a protrusion 44 having a size corresponding to that of the groove so as to be inserted into the groove 40 of the bed 20 on the lower surface as shown in FIG. 4. Is formed. As shown in FIG. 5, the support 30 has a protrusion 46 having a size corresponding to that of the groove so as to be inserted into the groove 42 of the bed 20. Similarly, as shown in FIG. 6, a protrusion 45 having a size corresponding to the groove protrudes from the bottom surface of the base 21 so as to be inserted into the groove 41 of the bed 20.

As shown in FIG. 2, when the holder 23, the support 30, and the base 21 are seated on the bed 20, the protrusions 44, 45, and 46 formed on each member are the bed 20. It fits into each groove 40.41.42 formed on it. In this state, when the fixing table 23, the support 30, and the base 21 are fastened and fixed to the bed 20 with the bolts 34, the coupling force of the grooves and the protrusions is added to the fastening force of the bolts so that the fastening force can be further increased. Will be.

In this embodiment, but the groove is formed on the bed 20 is illustrated, but is not limited thereto. For example, protrusions are formed on the bed 20 and grooves are formed in the holder 23, the support 30, and the base 21, and this may also belong to the technical spirit of the present invention.

In addition, according to the present embodiment, as shown in FIG. 2, a connecting bar 50 is inserted between the support 30 and the support 23 to support the support 30 and the support 23. have.

The connecting bar 50 is threaded at both ends and penetrated by the nut 51 after passing through the support 30 and the fixing stand 23.

In this way, the connection bar is held between the support 23 and the support 30 to fix the support and the support in the rolling process can be further prevented.

The base 21 has a cross-sectional structure having a dove tail shape as shown in FIG. 6, and the feed table 22 coupled to the base 21 also has a dovetail at the bottom surface thereof as shown in FIG. 7. A groove 47 having a shape is formed and engaged with the base 21.

Here, one side inner surface of the conveyance table 22 in contact with the inclined outer surface of the base 21 has a tapered structure so that the interval gradually increases from one end to the other end. The key is inserted into the gap between the base 21 and the feed table 22 to fill the play.

8 illustrates the key 48. As shown, the key has a structure in which one side of the key is tapered so as to correspond to a gap between the base 21 and the carriage 22 and gradually decreases in width. In addition, the key 48 has a structure in which a curved portion 49 is formed to be concave inward in a central portion on the opposite side of the tapered surface. This is because both ends of the key wear out before the center part as the feed table 22 repeatedly slides with respect to the base 21. The curved portion 49 may be formed in about 50% of the entire length of the key.

On the other hand, the two hydraulic cylinders (31a, 31b) are arranged side by side is fixed to the support (30). And the piston rod of each hydraulic cylinder (31a, 31b) is connected to the feed table (22). Each of the hydraulic cylinders 31a and 31b is connected to the hydraulic pump and the drain tank through a hydraulic line and is supplied with the necessary pressure oil to expand and contract.

Here, the rolling device includes a control unit for preventing the generation of the moment by adjusting the pressing force of the hydraulic cylinder (31a, 31b).

That is, due to the characteristics of the rolling mill, the rolling die 24 is positioned to be biased toward the one side hydraulic cylinder 31a from the center of the feed table 22. For this reason, when two hydraulic cylinders 31a and 31b pressurizing the feeder 22 when the raw material P enters between the rolling dies 24 and pressurize the feeder 22 at the same pressure, the rolling die is The pressure is further applied to the other hydraulic cylinder (31b) that is not located, the moment is generated in the feed table (22). Accordingly, the control unit adjusts the pressing force of the hydraulic cylinder 31b to prevent the moment from being generated.

10 is a hydraulic circuit diagram for driving each of the hydraulic cylinders. Referring to this, the control unit will be described below.

The control unit is installed on each hydraulic line 62 connecting the discharge line 61 and the hydraulic cylinders 31a and 31b connected from the hydraulic pump 60 to the respective solenoid valves 63a and 63b for applying pressure oil. , Which is installed on the hydraulic line 62 between the solenoid valve 63b of the one side hydraulic cylinder 31b and the discharge line 61 of the hydraulic pump 60 to reduce the amount of pressure oil supplied to the hydraulic cylinder 31b. And a reducing valve 64.

The pressure of the pressurized oil supplied to each hydraulic cylinder 31b is changed by the reducing valve 64 so that a difference occurs in the pressure pushing the feed table 22.

In the present embodiment, the reducing valve 64 is installed on the hydraulic line 62 connected to the hydraulic cylinder 31b located far from the rolling die 24 among the two hydraulic cylinders.

In addition, the control unit is to prevent the occurrence of reverse moment by changing the pressing force of each hydraulic cylinder in the absence of the material or when the roll processing of the material is completed.

To this end, the control unit is a detection unit for detecting when the conveyance table advances above the set value according to the expansion operation of the hydraulic cylinder (31a, 31b), and each hydraulic line (62) connected to each of the hydraulic cylinder (31a, 31b) The connection line 65 is connected to the) and the distribution valve 66 is installed on the connection line 65 to selectively open and close the connection line in accordance with the signal of the detection unit.

When the flow valve 66 is opened when necessary, the pressure applied to each hydraulic cylinder 31 is equalized while the hydraulic oil of each hydraulic line 62 is circulated through the connection line 65. Therefore, the pressing force of each hydraulic cylinder 31 which differed from each other becomes equal.

As shown in FIG. 9, the detection unit is installed at the end of the rod 80 and penetrated to the center of the support 30, and the rod 80 penetrated through the support 30. The member 81 includes a contact sensor 90 installed on the support 30 and in contact with the locking member to output a signal.

Therefore, when the conveyer 22 is advanced by the extension operation of the hydraulic cylinders 31a and 31b, the rod 80 installed on the conveyer 22 is moved with respect to the support 30, and the roll that is installed on the conveyer 22 is moved. As the die 24 penetrates into the material, the precursor is made. In this state, as described above, the pressing forces of the hydraulic cylinders 31a and 31b are different from each other to prevent the moment from being generated.

On the other hand, when the processing of the material (P) is completed or the material is not stuck in the rolling die 24, the conveyance table is advanced beyond the set value, the locking member 81 installed at the end of the rod 80 is supported on the support (30) It comes in contact with the installed contact sensor 90. In response to the signal of the contact sensor 90, the distribution valve 66 is operated to open the connection line (65). As the connection line 65 is opened, the pressures applied to each of the hydraulic cylinder 31a and the other hydraulic cylinder 31b are distributed to each other and the pressure is the same. In this way, by making the pressing force of the two hydraulic cylinders 31a and 31b the same, it is possible to prevent the occurrence of the reverse moment which may be generated by the pressure difference between the two hydraulic cylinders after the rolling die 24 is advanced by an appropriate stroke.

In this embodiment, the carriage 22 can adjust the movement amount, that is, the stroke length of the rolling die 24. To this end, the device has a structure in which the front end of the rod 80 and the locking member 81 are screwed together. Therefore, by adjusting the fastening position by locking or releasing the locking member 81 with respect to the rod 80, the distance from the carriage 22 to the locking member 81 is adjusted, and thus the rolling die 24 installed in the carriage 22 is provided. ) Stroke distance can be adjusted.

Further, the present rolling apparatus further includes a drain portion for quickly draining the pressurized oil when an abnormality occurs.

For this purpose, the drain portion is provided with a drain line 70 branched from one side of each hydraulic line 62 connected to the hydraulic cylinders 31a and 31b, and the hydraulic oil is installed on the drain line 70. Pilot connected to the check valve 71, the discharge line 61 is connected to the hydraulic pump 60 and the respective check valve 71 to block the movement to the pilot valve 71 to apply an open pressure to the check valve 71 A line 72 is provided at one side of the pilot line 72 and includes a control valve 73 selectively connecting the discharge line 61 and the pilot line 72.

Accordingly, when the control valve 73 is opened during the reverse operation of the hydraulic cylinders 31a and 31b, the hydraulic oil discharged from the hydraulic pump 60 is supplied to the pilot line 72 through the discharge line 61 to check valves. 71 will be opened.

Therefore, the hydraulic oil of each hydraulic cylinder 31 is quickly discharged through the drain line 70 connected to the hydraulic line 62 in accordance with the opening of the check valve 71, and the hydraulic cylinders 31a and 31b are reversed so that the transfer table 22 It is possible to quickly remove the pressure applied to).

In addition, the drain portion is provided with a sealing plate 83 provided with an elastic spring 82 between the locking member 81, and a fastening bar installed on the sealing plate 83 and penetrated outside the locking member 81 ( 84), the fastening bar 84 is further provided with a nut (85) for supporting the mill plate to the engaging member.

Accordingly, the sealing plate 83 is prevented from being separated while the nut 85 installed on the fastening bar 84 is caught by the locking member 81, and is caught in a state that the spring 85 is protruded outward from the locking member 81 by the elastic spring 82. It is supported by the member 81. .

When the transfer table 22 is moved so that the locking member 81 is moved toward the support 30, the elastic plate 82 protruding from the locking member 81 is pressed against the support 30 while being pressed against the support 30. Will be compressed. As mentioned in this state, when the hydraulic cylinders 31a and 31b are driven backward, the plate 83 is pushed out of the support 30 by the elastic return force of the compressed elastic spring 82, and the rod 80 is mediated. It will be quickly reversed the conveying table 22 installed.

In this case, the rolling apparatus may be applied to the structure using the air pressure in addition to the above structure or in addition to the above structure for the rapid backward of the feed table (22).

To this end, the present rolling device is an air line (95) which is installed in communication with the piston rod side chambers of each hydraulic cylinder (31a, 31b), as shown in Figure 9 and connected to the air line is installed in the air pressure to the chamber An air pump 96 to be applied includes a valve 97 for opening and closing the air line as necessary.

Accordingly, when the air pump 96 is driven, air is applied to the piston rod side chambers of the hydraulic cylinders 31a and 31b through the air line 95. Air applied to the chamber acts as a pressure to reverse the piston rod of each hydraulic cylinder. As mentioned above, when the hydraulic oil applied to the hydraulic cylinders 31a and 31b is drained and moved backward, the piston rod is quickly pushed by the air pressure applied to the chamber and the feed table 22 connected to the piston rod is opened. It is to be reversed quickly.

In the present rolling method, the rolling die 24 is formed by cutting the raw material P between the rolling dies 24 and rotating the pressing die 24 while pressing the rolling die 24 with the raw material P. Gradually increasing the rotational speed and pressing force of the rolling die 24 at low and low pressures, driving the rolling die 24 at high speed and high pressure, and gradually lowering the speed and pressure of the rolling die 24. do.

When the starting point of the starting material and the end point is called the whole process, the step of increasing the pressure and speed of the rolling die may be in the range of 10 to 30% of the entire process. In addition, the step of reducing the speed and pressure of the precursor die may be in the range of 10 to 30% of the entire process. The step of maintaining the precursor die at high speed and high pressure may be appropriately adjusted according to the step.

If it is less than the above range, the pressure and torque is suddenly applied to the material, causing an abnormality in the material or the device, if exceeding the above range, the high-speed high-pressure holding interval is reduced to reduce productivity.

Looking at the process of rolling the material according to the present rolling device and the rolling method as follows.

When the raw material P is transferred to the rolling position and the rolling operation is started, the solenoid valve 63 installed on the hydraulic line 62 is turned to connect the hydraulic line 62 to the discharge line 61. The pressure oil discharged from the hydraulic pump 60 is applied to the hydraulic cylinder 31 through the hydraulic line to extend the hydraulic cylinder.

As the hydraulic cylinder 31 is extended, the carriage 22 connected to the piston rod of the hydraulic cylinder is slid and moved relative to the base 21.

As the feed table 22 is moved, the gap between the rolling die 24 installed in the feed table 22 and the rolling die installed in the fixing table 23 is reduced. The pair of precursor dice 24 bite the material (P) located therebetween.

At this time, the rolling die 24 for rolling the raw material P is biased to one side from the center of the two hydraulic cylinders 31a and 31b. In this state, a moment is generated in the feeder 22. The reducing valve 64 installed in the hydraulic circuit reduces the pressing force applied to one hydraulic cylinder 31b, thereby generating a moment by changing two hydraulic cylinder pressing forces. Will be prevented.

However, when the feed table 22 is advanced in the state in which the material P is not bitten by the rolling die 24, the distribution valve 66 installed in the connection line 65 connecting the hydraulic line 62 is operated. As the flow path is opened, the pressures on the two hydraulic lines become equal. Therefore, the pressing force of each hydraulic cylinder (31a, 31b) is the same, it is possible to prevent the transfer table from twisting in the opposite direction.

When the driving motor 26 is driven, power is transmitted to the rolling die 24 through the reduction gear 27, the universal joint 28, and the expansion pipe 29 to rotate the rolling die.

As the hydraulic cylinder 31 is extended and actuated to press the rolling die 24 to the raw material P, the raw material P is rolled as the rolling die 24 rotates according to the operation of the driving motor 26. Here, in the initial stage of rolling the raw material P, the pressing force of the rolling die 24 by the hydraulic cylinder 31 and the rotational force of the rolling die 24 by the driving motor 26 gradually start at a low pressure low speed. Will increase.

When the pressing force and speed of the rolling die reach a peak, the rolling process is performed while maintaining the pressing force and speed.

The rolling device is a large shearing force is applied to the bolt 34 for fixing the support 23 and the support 30 and the base 21 on the bed 20 by performing a high-capacity rolling operation at high pressure and high speed. As mentioned above, the fixing base 23, the support 30, and the base 21 have grooves 40, 42, and 41 formed with protrusions 44, 46, and 45 formed integrally on the bottom surface thereof. ) And it is fixed in the interlocking state, which greatly reduces the shear force applied to the bolt.

Therefore, even if the rolling pressure and speed is increased, the wear of the bolt can be reduced, and the rolling capacity can be increased in comparison with the conventional rolling device in the same specification, thereby enabling the implementation of a large rolling device.

Here, after the rolling process is maintained while maintaining the high pressure and high speed, the pressure of the hydraulic cylinder 31 and the rotational speed of the driving motor 26 are gradually reduced.

As described above, by gradually increasing the pressure and speed at the beginning of the rolling process and gradually decreasing the pressure and speed to the end of the rolling process, it is possible to carry out the rolling of the material (P) under high pressure and high speed and to increase productivity. .

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

1 is a plan view showing the overall configuration of a rolling device according to an embodiment of the present invention.

2 is a front view showing a rolling apparatus according to an embodiment of the present invention.

3 is a view showing a bed of a rolling device according to an embodiment of the present invention.

4 to 8 is a perspective view showing each component installed in the bed of the rolling apparatus according to an embodiment of the present invention.

Figure 9 is a block diagram showing a component for adjusting the stroke of the rolling apparatus according to an embodiment of the present invention.

10 is a hydraulic circuit diagram of a rolling device according to an embodiment of the present invention.

Claims (12)

A bed, a base installed on the bed, a transport table slidably installed on the base, a fixed table spaced apart from the transport table, and a rolling die provided on the transport table and the fixed table, respectively, and paired with each other. And a driving unit for driving the rolling die, and a pressing unit installed on the bed to apply a transfer pressure to the transfer table, and a protrusion or a groove is formed in the base or the fixed base fixed to the bed, and the bed is Rolling device which engages each other by forming grooves or projections corresponding to the projections or grooves. The method of claim 1, The pressurizing portion further includes a support installed on the bed and at least one hydraulic cylinder installed on the support and connected to the transport for pushing the transport, the support is formed with a projection or groove on the contact surface with the base and The base is a precursor device that the groove or the projection corresponding to the projection or the groove is formed to mesh with each other. The method of claim 2, Rolling device further comprises a connection bar is installed between the fixing and the support to add a support force. The method of claim 1, And a key fitted in a gap between the transfer table and the base, wherein the key has a curved portion formed in a concave portion inwardly at a central portion thereof. The method of claim 2, It is provided on the hydraulic circuit for supplying the hydraulic oil to each of the hydraulic cylinder includes a control unit for adjusting the pressing force of each hydraulic cylinder, The control unit is installed on each hydraulic line connecting the discharge line and each hydraulic cylinder connected from the hydraulic pump for supplying the hydraulic oil to each hydraulic cylinder, each solenoid valve for applying the hydraulic oil, the solenoid valve and the hydraulic pump of one hydraulic cylinder Rolling apparatus is installed on the hydraulic line between the reducing apparatus including a reducing valve for reducing the amount of pressure oil supplied to the hydraulic cylinder. The method of claim 5, wherein The control unit further comprises a connection line connected to the hydraulic line connected to each of the hydraulic cylinders, and the distribution valve is installed on the connection line for selectively opening and closing the connection line. The method of claim 6, The control unit includes a rod installed in the conveyance and penetrating the support, a locking member installed at the tip of the rod passing through the support, the contact sensor is installed on the support and in contact with the locking member to output the flow valve control signal Rolling device included. The method of claim 5, wherein Further comprising a drain for quickly draining the pressure oil is installed on the hydraulic circuit for supplying pressure oil to each of the hydraulic cylinder, The drain portion includes a drain line branched from one side of the hydraulic line connected to the hydraulic cylinders, a check valve installed at the drain line to block hydraulic oil from moving to the drain line, a discharge line connected to the hydraulic pump, and the respective drain lines. And a control valve connected between check valves to apply an open pressure to the check valve, and a control valve installed at one side of the pilot line to selectively connect the discharge line and the pilot line according to a control signal of the detector. The method of claim 8, The rod tip and the catching member is screwed coupled. The method of claim 9, The roll plate further includes a plate installed with the elastic springs interposed therebetween, a fastening bar installed on the close plate to penetrate the outside of the catching member, and a nut installed at the tip of the fastening bar to support the plate on the catching member. Device. In the rolling method of processing the material by rotating the material while sandwiching the material between the rolling die and pressing the rolling die to the material,  Gradually increasing the rotational speed and pressing force of the rolling die from a low pressure low pressure; Driving the rolling die at high speed and high pressure; Gradually lowering the speed and pressure of the precursor die Rolling method comprising a. The method of claim 11, When the starting point and the end point of the precursor of the material are referred to as the entire process, the step of increasing the pressure and speed of the precursor die is performed in the range of 10 to 30% of the entire process, and lowering the speed and pressure of the precursor die. Is a rolling method in the range of 10 to 30% of the entire process.

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