KR102033907B1 - Shock Absorber of Press - Google Patents

Abstract

The present invention relates to a shock absorber coupled to a bed on which a die is placed in a press to support a load according to the operation of the press. The first hydraulic pump, the first pipe through which the working fluid flows between the hydraulic cylinder from the first hydraulic pump, the first relief valve for discharging the pressure fluid to the outside when the working fluid filled in the hydraulic cylinder exceeds the first set pressure And a flow control valve for adjusting the flow rate of the working fluid supplied from the first hydraulic pump to the hydraulic cylinder so that the piston of the hydraulic cylinder is disposed at the set up position, and the compressive gas is compressed to the second set pressure set according to the capacity of the press. Accumulator, the second pipe communicating with the accumulator 50, so that the working fluid flows only from the first pipe to the second pipe Limited is constituted by a check valve, and a control unit that controls the operation and setting of the operation of the buffer to the input of the buffer.

Description

Shock Absorber of Press

The present invention relates to a shock absorber of a press, and more particularly, to a shock absorber supporting a load acting on a die during molding operation in a press.

A press is a machine for seating a workpiece on a die and hitting it with a punch to apply pressure to the workpiece to cut the workpiece or to form a predetermined shape.

Presses mainly for processing metal objects are operated with a force of hundreds to tens of thousands of tons to apply pressure to the plate placed on the die, so that a considerable force is applied to the die and the punch.

Such a force mainly acts on the object to be molded, causing deformation in the object, but when a temporary impact load acts on the object, it causes a crack in the object, as well as a die and punch forming a press, as well as a bed on which the die is placed. Even significant impact loads are applied to cause breakage.

Therefore, in the conventional press, the lower side of the bed on which the die is placed absorbs and buffers the impact load applied by the press, so that the load acting on the object is gradually applied to the object, so that the object is processed without cracking, A shock absorber is provided to prevent the impact load from being applied.

Such a shock absorber comprises a pneumatic device disposed at the bottom of a bed on which a die is placed, as disclosed in Korean Utility Model Publication No. 1999-064306 (Document 1) and Korean Patent Publication No. 0134885 (Document 2).

Such a pneumatic device places a cylinder filled with nitrogen gas that exhibits a linear compression behavior, and when the piston is coupled to the bed and a punch is applied to the die placed on the bed, the piston contracts against the cylinder and the nitrogen gas in the cylinder. The compression is applied to absorb the impact load and the piston is pushed down to form the workpiece by punch and die.

However, in the shock absorber made of a pneumatic cylinder, since the gas is used as the working medium, the piston must be very large in order to receive a large force, and the stroke length of the piston is very long due to the compressibility of the gas.

Therefore, the shock absorbers made of pneumatic cylinders have to be arranged at the bottom of the press with very large diameters and lengths, so the apparatus becomes very large, especially in order to install the shock absorbers, excavation to a substantial depth below the ground of the factory where the press is installed. There is a problem that must be done.

Document 1: Korean Utility Model Publication No. 1999-064306 Document 2: Korean Patent Publication No. 0134885

The present invention is to provide a shock absorber made of a hydraulic cylinder in consideration of the problems of a shock absorber of a press made of a pneumatic cylinder that has been conventionally used.

Although hydraulic cylinders use oil as a working medium, liquids such as oils are incompressible fluids and thus cannot absorb shock loads on the piston. However, in the present invention, hydraulic cylinders are used as a device for supporting a bed on which a die is placed. It is an object of the present invention to provide a shock absorber having a configuration that absorbs the impact load applied to the press and allows a relatively uniform load to be applied to the molding object.

The problem to be solved by the present invention described above is achieved by the shock absorber of the present invention that is coupled to the bed on which the die is placed in the press to support the load according to the operation of the press.

The shock absorber of the present invention,

A hydraulic cylinder 50 having a piston filled with a working fluid at a first set pressure, the piston being coupled to the bed and configured to act upon a load applied to the bed through the die during the molding operation of the press; A first hydraulic pump 11 for supplying a working fluid to the hydraulic cylinder 50; A first pipe 1 through which a working fluid flows from the first hydraulic pump to the hydraulic cylinder; A branch which is branched from the first pipe 1 between the hydraulic cylinder 50 and the first hydraulic pump 11 and discharges the pressure fluid to the outside when the working fluid filled in the hydraulic cylinder exceeds the first set pressure; 1 relief valve 21; The flow rate of the working fluid supplied from the first hydraulic pump 11 to the hydraulic cylinder 50 is disposed between the point where the first relief valve 21 branches in the first pipe 1 and the hydraulic cylinder 50. A flow rate control valve 22 which adjusts the piston of the hydraulic cylinder 50 to be disposed at a set up position, and constitutes a proportional control valve; The accumulator in which the compressive gas is filled to a predetermined pressure, which is set according to the capacity of the press, is compressed to a second set pressure which is higher than the first set pressure and lower than the pressure at which the working fluid is pressurized in the hydraulic cylinder during the molding operation of the press. 46; A second pipe 2 branched from the first pipe 1 between the hydraulic cylinder 50 and the flow control valve 22 to communicate with the accumulator 50; A check valve 23 provided between the first pipe 1 and the second pipe 2 to restrict the working fluid to flow only from the first pipe 1 to the second pipe 2; And a control unit for controlling the operation of the shock absorber and inputting setting values relating to the operation of the shock absorber.

In the preparatory operation of the press-molding operation, the first hydraulic pump 11 is operated to fill the hydraulic cylinder with pressurized working fluid to the hydraulic cylinder through the first pipe 1 at the first set pressure, and the piston is controlled by the flow control valve. Configured to be in the elevated position set by

In the molding operation of the press, the flow control valve 22 is closed, and when the piston of the hydraulic cylinder 50 is lowered by the molding operation of the press, the working fluid in the hydraulic cylinder 50 is discharged and passes through the check valve 23. Is introduced into the accumulator 46 through the second pipe 2 to compress the compressible gas of the accumulator,
A second hydraulic pump 17 for supplying a working fluid to the accumulator 46; A third pipe connected between the second hydraulic pump 17 and the check valve 23 to the second pipe 2 to transfer the working fluid supplied from the second hydraulic pump 17 to the accumulator 46 ( 3); A pressure sensor 36 branched to the third pipe 3 to measure the pressure of the working fluid flowing through the third pipe 3; And a second to discharge the working fluid from the second hydraulic pump 17 to the outside when the pressure of the working fluid filled in the accumulator 46 reaches the second set pressure according to the measurement signal from the pressure sensor 36. It further comprises a relief valve 31 is configured to fill the accumulator 46 to the working fluid at a second set pressure prior to the preparatory operation of the molding operation.

In the shock absorber according to the present invention, the load according to the pressing force applied to the die by the punch according to the molding operation of the press acts directly on the hydraulic cylinder coupled to the bed on which the die is placed, and the load by such action is finally compressible. The gas is pressurized and absorbed by the charged accumulator.

The hydraulic system of the accumulator and the second pipe to which the accumulator is connected is filled at a higher pressure than the hydraulic system of the hydraulic cylinder and the first pipe to which it is connected, but before the forming operation of the press the two hydraulic systems are separated by a check valve. have.

Therefore, the operation of filling the accumulator to the set pressure and the operation of filling the hydraulic cylinder to the set pressure are made separately, and the state filled with different pressures can be maintained.

When the hydraulic cylinder is pressurized by the forming operation of the press and the pressure of the working fluid rises, the pressurized working fluid of the hydraulic cylinder flows to the accumulator and the compressive gas of the accumulator is compressed to absorb the impact of the forming operation of the press. In addition, the working fluid of the hydraulic cylinder flows toward the accumulator to allow downward movement of the die, thereby forming a work piece placed between the punch and the die.

According to the configuration and operation of the shock absorber according to the present invention, a hydraulic cylinder can be used as a device for supporting the die in place of a pneumatic cylinder having a long stroke length and a large diameter as the shock absorber of the press.

Thus, it is not necessary to deeply form a space in the lower part of the press in order to arrange the shock absorber, and a small diameter cylinder can be easily installed in the lower part of the press.

In addition, since the set pressure of the accumulator can be varied, the shock absorbing operation according to the press operation can be adjusted according to the press capacity or the operating pressing force without changing the configuration of the shock absorber.

On the other hand, as an additional feature of the shock absorber according to the present invention, the pressure of the working fluid, which is arranged branching from the second pipe 2 and acts by the lowering of the piston of the hydraulic cylinder 50 in the forming operation of the press, It may further include a logic valve (29, 30) to open when exceeding the two set pressure to discharge the working fluid from the second pipe (2) to the outside.

According to this additional feature, the high-pressure working fluid generated in the hydraulic cylinder is introduced into the accumulator by the load according to the forming operation of the press and the die's behavior, and the accumulator supports the load, but it flows out by the operation of the hydraulic cylinder. When the flow rate of the working fluid exceeds the capacity of the accumulator, the logic valve is opened to discharge the working fluid, thereby overloading the accumulator and the system for delivering the working fluid to it and supporting the load according to the forming operation of the press. Unwanted things are prevented.

delete

delete

Further, as a further feature of the present invention, a third relief is branched between the flow control valve 22 and the hydraulic cylinder 50 and connected to the first pipe 1, and is opened at an opening pressure higher than the second set pressure. The valve 27 is further included, and the opening pressure of the third relief valve 27 may be configured to be set to a pressure which may cause breakage or failure of the shock absorber during the molding operation of the press.

According to this further feature, the third relief valve, which is arranged in close proximity to the hydraulic cylinder, is opened and operated even when a momentary impact load is applied at the beginning of the press forming operation so that the working fluid is discharged from the hydraulic cylinder at a very high pressure. By discharging the fluid, impact loads that cause cracks or failures in the hydraulic system connected from the hydraulic cylinders to the accumulators or which cause cracks in the workpiece in the shaping operation of the press can be reduced.

1 is a front view schematically showing a state in which a press with a shock absorber according to an embodiment of the present invention is installed.
2 to 5 is a circuit diagram showing the configuration of a shock absorber according to an embodiment of the present invention, Figure 2 shows a state in which the accumulator is filled with the working fluid, Figure 3 is a state in which the hydraulic cylinder is filled with the working fluid 4 shows the cushioning action of the shock absorber in the state in which the press is operated, and FIG. 5 shows the state in which the hydraulic cylinder is lowered to lower the bed of the press.

Hereinafter, with reference to the drawings will be described the configuration and operation of the shock absorber of the press according to the embodiment of the present invention as a specific content.

In the following description and throughout the specification, the expression 'downstream' or 'upstream' is used, where the expression 'downstream' or 'upstream' does not mean upward and downward in azimuth, but flows downstream from the flow of the working fluid and upstream to the opposite side. If the flow of working fluid is changed, it refers to upstream and downstream based on the direction of the changed flow.

The shock absorber according to the present embodiment is disposed in a space formed below the ground of the factory where the press 100 is installed, as in a conventional shock absorber.

1, the space 2 is formed under the ground by the concrete structure 1, and the frame 7 of the press is supported by the support structure 3 provided in this space.

In the space 2, the shock absorber of the present embodiment is arranged, and above the shock absorber, two hydraulic cylinders 50 are disposed below the bed 8 of the press to support the bed 8 and to support the bed 8 ) Is subjected to a load at the time of press molding to be applied.

Below the hydraulic cylinder 50 is a manifold block 49 for supplying working fluid to the hydraulic cylinder, and hoses 48 for supplying working fluid to the manifold block are shown. In addition, six accumulators 46 arranged in parallel are arranged as elements of the shock absorber.

Since the drawing showing such an appearance does not show a specific configuration of the shock absorber, the configuration and operation of the shock absorber of the present embodiment will be described below with reference to FIGS. 2 to 5, which are hydraulic circuit diagrams of the shock absorber.

2 to 5 show the same hydraulic circuit diagram, but in each of the drawings highlights the piping through which the working fluid flows in the operating state to be shown in the figure, the configuration related to each operating state in the following in sequence In the description, such an explanation will be made with reference to the corresponding drawings showing the operating states.

Prior to the description of the specific configuration, the basic configuration and main operation state of the shock absorber of this embodiment will be described.

The shock absorber of the present embodiment is largely divided into a hydraulic cylinder 50 having a piston coupled to the lower portion of the bed on which the die is placed in the press to support the load applied to the bed and operating up and down according to the movement of the bed, and the lowering of the bed. When the piston is operated downward, the working fluid discharged from the hydraulic cylinder is introduced into the accumulator 46 and the hydraulic cylinder 50 and the accumulator 46 configured to compress the nitrogen gas filled therein. As used to control the operation of the first hydraulic pump 11 and the second hydraulic pump 17 to supply, and the shock absorber of this embodiment, sensors for measuring various parameters, various set values are input and sensors A control unit (not shown) that performs control in accordance with the information from the control valve, various valves and the working fluid to limit the pressure or flow rate of the working fluid or to switch the flow of the working fluid It consists of flowing pipes.

The shock absorber of this embodiment has four operating states including these configurations.

Firstly, the accumulator 46 is filled with working fluid at a pressure set according to the capacity of the press. During the forming operation of the press, the working fluid in the hydraulic cylinder 50 is pressurized by the force for punching the die and flows into the accumulator 46.

The pressure of the working fluid from the hydraulic cylinder 50 compresses the nitrogen gas filled in the accumulator 46 while absorbing the impact in the press and supporting the load.

The accumulator 46 is pre-compressed to a level of, for example, 50% of the maximum applicable pressure, which is determined according to the capacity of the press and lower than the pressure applied during the molding operation of the press, prior to the molding operation of the press. This is accomplished by pressurizing the working fluid by the hydraulic pump 17 to fill the accumulator 46.

Secondly, the hydraulic cylinder 49 is filled with a working fluid at a set pressure.

After the hydraulic cylinder 50 is lowered according to the molding operation of the press, the hydraulic cylinder 50 should be raised to return to the original position for the next molding operation, and should be placed in the rising position waiting for the press molding operation even in the initial setting of the shock absorber.

In such an operation, the first hydraulic pump 11 is operated to fill the working fluid so that the piston of the hydraulic cylinder 50 rises to a set working position, the working fluid acting on the hydraulic cylinder 50 in the molding operation of the press. It is pressurized to a pressure of, for example, 30 bar so that it can be subjected to impact loads. However, the filling pressure of the hydraulic cylinder 50 is determined to be lower than the filling pressure of the accumulator 46.

Thirdly, the press performs the molding operation so that the load resulting from the lowering of the punch and pressurizing in contact with the work object acts on the piston of the hydraulic cylinder 50, thereby communicating with the hydraulic cylinder 50 and it. The working fluid filled in the pipe is pressurized, and the pressurized fluid flows and flows to the accumulator 47 and other elements, so that the punch and die of the press are absorbed while absorbing the impact and the load of the forming operation of the press. It is an operation to pressurize the workpiece so as not to cause cracks.

Fourth, the operation of lowering the piston of the hydraulic cylinder 50 to lower the bed on which the die is placed for replacing the die of the press. In this lowering operation, no pressure is applied to the working fluid since the pressure according to the operation of the press is applied or not.

With respect to the above four operations, the configuration related to each operation will be described.

First, with reference to FIG. 3, the configuration related to the second operation, that is, the operation of filling the hydraulic cylinder 49 with the working fluid at the set pressure will be described.

As a configuration for supplying a working fluid to the hydraulic cylinder 50, a first hydraulic pump 11 is provided, and the first hydraulic pump 11 is coupled to and driven by the electric motor 13 by a coupling 12. The suction of the working fluid is carried out from the oil tank (not shown) of the working fluid through the filter 10.

The working fluid discharged by the first hydraulic pump 11 is supplied to the hydraulic cylinder 50 through the first pipe 1, and the first pipe 1 does not mean a single pipe, but several hoses. It means a series of flow path of the working fluid consisting of a pipe and the like is made of one working fluid flow.

Downstream of the first hydraulic pump 11, a second check valve 15 is provided to prevent the working fluid from flowing back. Downstream of the first hydraulic pump 11 is a pressure gauge 33 for allowing the operator to check the pressure. It is branched from and arranged.

The downstream of the branch point of the pressure gauge 33, the first relief valve 21 is arranged branched from the first pipe (1).

The first relief valve 21 allows the hydraulic cylinder 50 to be filled with the working fluid at the set pressure. In the shock absorber of the present embodiment, the set pressure of the hydraulic cylinder 50 is set to 30 bar, so that the first pipe When the pressure of the working fluid flowing in (1) exceeds this set pressure, the first relief valve 21 is opened so that the working fluid discharged from the first hydraulic pump 11 is not supplied to the hydraulic cylinder 50, but the first pressure. It is discharged through the relief valve 21 and returned to an oil tank (not shown).

A flow rate control valve 22 is provided downstream of the branch point of the first relief valve 21.

The flow rate control valve 22 is constituted by a proportional control valve, and the operation is started by the first solenoid valve 261 for operation control that controls the first logic valves 29 and 30 to be described later. ) To control the flow rate of the working fluid supplied to the hydraulic cylinder (50).

The hydraulic cylinder 50 is provided with a linear scale (not shown) for sensing the position of the piston, and receives a signal relating to the position of the piston from the linear scale, and is supplied to the hydraulic cylinder 50 according to the signal. The flow rate of the fluid is regulated.

In the supply of the working fluid to the hydraulic cylinder 50, the flow control valve 22 is opened so that the working fluid flows at a relatively high flow rate to shorten the working time, but if the piston is close to the set height, that is, the press ready position for operation, By reducing the flow rate to the hydraulic cylinder 50, when the piston reaches the set height, it is controlled so that the impact due to the sudden stop of the piston operation does not occur.

Downstream of the flow control valve 22 are five first check valves 23. The first check valves 23 are arranged in parallel between the first pipe 1 and the second pipe 2 branched to the accumulator 46.

The first check valve 23 allows the flow of the working fluid from the first pipe 1 to the second pipe 2 between the hydraulic cylinder 50 and the flow control valve 22, and allows the second pipe ( The flow of the working fluid from 2) to the first pipe 1 is not allowed.

As will be described later in connection with the first operation of filling the accumulator 46 with the working fluid, in the operation of filling the accumulator 46 the second pipe 2 is the accumulator 46 which is determined according to the capacity of the press. Since there is a working fluid having a pressure of 120 bar or more, the working fluid of the first pipe 1 pressurized to 30 bar does not flow through the first check valve 23 to the second pipe 2, and The high pressure working fluid of the two pipes 2 does not flow to the first pipe 1 by the action of the first check valve 23.

The first pipe 1 is branched into five downstream of the flow control valve 22 and connected to the manifold block 49 via a hose 48.

The manifold block 49 is connected together to two hydraulic cylinders 50, which are installed together in one press and constitute a shock absorber, so that the working fluid from the first hydraulic pump 11 is connected to each hydraulic cylinder 50. The working fluid flowing into and discharged from each of the hydraulic cylinders 50 during the molding operation of the press flows to the first pipe 1 together.

According to this configuration, in order to raise the piston of the hydraulic cylinder 50 to the operating position to start press molding and to fill the hydraulic cylinder 50 with the pressurized working fluid at the set pressure, firstly, the first hydraulic pump 11 ) Starts operation and draws the working fluid from the oil tank and discharges it to the first pipe 1. In addition, the first solenoid valve 261 for operation control opens the flow control valve 30 in response to a signal from the controller so that the working fluid from the first hydraulic pump 11 flows downstream.

The working fluid is filled in the hydraulic cylinder 50 through the manifold block 49, the piston of the hydraulic cylinder 50 gradually rises and the pressure of the working fluid also rises.

When the pressure of the working fluid exceeds 30 bar, the first relief valve 21 upstream of the flow control valve 22 is opened, so that the working fluid is discharged through the first relief valve 21, so that the pressure of the working fluid is 30 bar. Is maintained.

When the piston reaches the set position, the flow control valve 22 is closed by the first solenoid valve 261 in response to a signal from the linear scale in the hydraulic cylinder 50, filling the hydraulic cylinder 50 and raising the piston. Ends.

When this preparation process is finished, the press is in a state capable of forming operation.

Prior to this filling of the hydraulic cylinder 50, the first operation, ie filling and pressure setting of the working fluid to the accumulator 46, is made.

Hereinafter, with reference to FIG. 2, the configuration related to the operation of filling the accumulator 46 will be described.

The second hydraulic pump 17 is connected to and operated by the coupling 18 to the electric motor 19, and sucks the working fluid from the oil tank through the filter 16 and discharges it to the third pipe 3. The third pipe 3 is connected to the second pipe 2 at a point between the first check valve 23 and the accumulator 46.

Downstream of the second hydraulic pump 17 in the third pipe 3, a pressure gauge 34 for checking the pressure of the working fluid in the second pipe 2 is disposed, and downstream of the third hydraulic valve 17, a third check valve ( 28) is arranged.

The third check valve 28 allows the flow of the working fluid from the second hydraulic pump 17 to the second pipe 2, and the working fluid from the second pipe 2 to the second hydraulic pump 17 side. Does not allow the flow of.

Downstream of the third check valve 28, a pressure sensor 36 is arranged branched from the third pipe 3 so that the pressure of the working fluid in the third pipe 3 can be measured to determine the pressure measured by the controller. Send the signal.

Meanwhile, the second relief valve 31 and the first logic valves 29 and 30 are disposed at the point where the third pipe 3 is connected to the second pipe 2.

The working fluid from the second pipe 2 flows in parallel into the valve cover 30 and the valve body 29 of the first logic valve made of orifices, and the working fluid flowing into the valve cover 30 is second. It is supplied to the relief valve 31. Since the first logic valves 29 and 30 operate in the open operation during the molding operation of the press, this will be described later.

The second relief valve 31 disposed downstream of the valve cover 29-1 of the first logic valve is composed of a proportional control valve, and the opening pressure is set to the filling pressure of the accumulator 46.

The second relief valve 31 is started by the first solenoid valve 261 for operation control, and the opening and closing operation is performed in accordance with the pressure of the working fluid in the third pipe 3 measured by the pressure sensor 36. Is done.

A manifold block 45 is disposed in the accumulator 46, and the working fluid flows from the third pipe 3 through the second pipe 2 into the manifold block 45 to each accumulator 46. Supplied to.

The accumulator 46 is a bladder-type accumulator initially filled with nitrogen gas at 80 bar, and as it is filled with the working fluid from the second hydraulic pump 17, the nitrogen gas is compressed and the pressure rises.

As the supply of the working fluid continues, the pressure of the working fluid filled in the accumulator 46 increases, and when the set pressure reaches, for example, 120 bar, the measurement from the pressure sensor 36 measured in the third pipe 3 is reached. In response to the signal, the second relief valve 31 is opened, and the second hydraulic pump 17 is in an idle state. Since the accumulator 46 and the second pipe 2 and the third pipe 3 are always in communication with each other, if the pressure of the working fluid therein occurs at a certain level, for example 5 bar, from the set pressure, In response to the measurement signal from the pressure sensor 36, the second relief valve 31 is closed to start the supply of the working fluid by the second hydraulic pump 17 and the pressure of the working fluid is raised to the set pressure.

This completes the filling of the accumulator 46. Upon completion of filling, the second pipe 2 is filled with 120 bar of working fluid, and in the subsequent operation of filling the hydraulic cylinder 50, the working fluid flowing through the first pipe 1 has a set pressure of 30 °. Since the bar does not flow into the second pipe 2 through the first check valve 23.

When the filling of the accumulator 46 and the filling of the hydraulic cylinder 50 are completed, preparation for forming operation of the press is completed.

Next, referring to Fig. 4, the configuration of the shock absorber relating to the third operation, that is, the molding operation of the press, will be described.

When the press is operated so that the punch is lowered to come into contact with the metal material as the work object and the pressing force is applied to the die, the force according to the operation of the punch applied to the die is transmitted to the hydraulic cylinder 50.

Due to the force acting on the piston of the hydraulic cylinder 50, the working fluid in the hydraulic cylinder 50 rises in pressure according to the load applied by the punch and is discharged from the hydraulic cylinder 50 in accordance with the downward movement of the piston.

The working fluid discharged from the hydraulic cylinder 50 flows into the first pipe 1 through the manifold block 49, but the downstream flow control valve 22 is closed by the operation of the first solenoid valve 261. The working fluid does not flow towards the first hydraulic pump 11.

On both sides of the first check valve 23, the second pipe 2 is filled with a working fluid of 120 bar, which is the set pressure of the accumulator 46, and the first pipe 1 is filled with the hydraulic cylinder 50. Filled with 30 bar of working fluid, no working fluid flows from the first pipe 1 to the second pipe 2 before the press is operated.

However, due to the load applied to the hydraulic cylinder 50 during the molding operation of the press, the working fluid in the hydraulic cylinder 50 is at a pressure higher than the pressure of the working fluid of the accumulator 46 and the second pipe 2. Pressurized, this high pressure acts on the working fluid of the first pipe 1, whereby the working fluid flows into the second pipe 2 through the first check valve 23.

On the other hand, in the 1st piping 1, the 3rd relief valve 27 branching from the 1st piping 1 is arrange | positioned between the flow control valve 22 and the hose 48, and this 3rd relief valve 27 ) Is configured to open at a pressure of 210 bar.

At the beginning of the press operation, i.e. at the moment the punch contacts the workpiece, an impact load may be applied, which may cause a pressure of up to 400 bar to the working fluid. Etc., but when the opening pressure of the third relief valve 27, i.e., a high pressure exceeding 210 bar is applied, the third relief valve 27 is opened so that the working fluid is discharged from the first pipe 1 to the third. Discharged through the relief valve 27 prevents the pipe or other parts from being damaged by the impact load.

In the forming operation of the press, the working fluid from the hydraulic cylinder 50 flows into the second pipe 2 through the first check valve 23, and the third check valve 28 provided in the third pipe 1. This does not flow to the second hydraulic pump 17.

The working fluid enters each accumulator 46 through the manifold block 45, and the working fluid is reduced by a volume which is reduced as the nitrogen gas of the accumulator 46 is compressed by the high pressure working fluid. 46).

As the working fluid is discharged from the hydraulic cylinder 50 due to the compression of the nitrogen gas in the accumulator 46 and the inflow of the working fluid accordingly, the piston of the hydraulic cylinder 50 is lowered as the working fluid flows. Done.

On the other hand, the second relief valve 31 connected to the second pipe 2 is closed by the first solenoid valve 261, so that the second relief valve 31 is held in the second pipe 2 during the press molding operation. Although the working fluid does not flow into the furnace, the working fluid may flow into the valve body 29 and the valve cover 30 of the first logic valve provided upstream of the second relief valve 31.

When the instantaneous flow rate of the working fluid flowing into the second pipe 2 through the first check valve 23 during the molding operation of the press exceeds the storage limit of the accumulator 46, the valve cover of the first logic valve The working fluid flowing into the valve 30 is opened to the valve body 29 so that the valve body 29 of the first logic valve is opened so that the working fluid is discharged to the outside through the first logic valve, and the hydraulic cylinder ( The downward movement of the piston of 29 is made continuously.

When the punch is lowered in the forming operation of the press to press the workpiece by the above operation, the operation of the punch and the die against the workpiece is not to apply an instantaneous and shocking pressing force. The working fluid of the combined hydraulic cylinder 50 is pressurized, the pressurized working fluid flows into the accumulator 46, and the compressive gas of the accumulator is compressed, so that the working fluid flows into the accumulator 46 and the hydraulic cylinder ( Since the piston of 50) is lowered while being supported by the pressurized working fluid, the die is lowered so that a pressing force that does not rise relatively rapidly is formed to be formed on the object to be processed.

Finally, referring to FIG. 5, a configuration relating to an operation of lowering the piston of the hydraulic cylinder 50 to lower the bed on which the die is placed for replacing the die and the punch of the press will be described.

Between the branch points of the flow control valve 22 and the third relief valve 27 in the first pipe 1, the second logic valves 24 and 25 and the second solenoid valve 26 for controlling the operation thereof are disposed. Branched and arranged.

The valve body 24 and the valve cover 25 of the second logic valve are connected in parallel to the pipe branched from the first pipe 1, and the second solenoid valve 262 is connected downstream of the valve cover 25. The output port of the second solenoid valve 262 is connected to the valve body 24.

Through this, the opening and closing operation of the valve body 24 of the second logic valve is controlled by the second solenoid valve 262.

When the bed is lowered for die replacement of the press, the second solenoid valve 26 is controlled to open the second logic valves 24 and 25. At this time, the first pipe 1 is filled with a working fluid of 50 bar, which is the filling pressure of the hydraulic cylinder 50, and the second pipe 2 is filled with a working fluid of 120 bar, the filling pressure of the accumulator 46. It is.

Therefore, when the second logic valves 24 and 25 connected to the first pipe 1 are opened, the working fluid of the first pipe 1 flows out through the valve body 24 of the second logic valve to provide oil. Recovered to the tank, and thereby the piston of the hydraulic cylinder 50 is lowered so that the bed can be lowered. Since the working fluid of the second pipe 2 does not flow into the first pipe 1 due to the check valve 23, the outflow or pressure drop of the working fluid of the accumulator 46 and the second pipe 2 does not occur. Do not.

While the configuration and operation of the shock absorber according to the embodiment of the present invention have been described above, the present invention is not limited to the embodiment, and various changes, modifications, and additions of components are possible within the scope of the claims.

11: first hydraulic pump 17: second hydraulic pump
21: first relief valve 22: flow control valve
23: first check valve 31: second relief valve
29, 30: first logic valve 24, 25: second logic valve
46: accumulator 50: hydraulic cylinder

Claims (4)

A shock absorber coupled to the bed on which the die is placed in the press to support the load according to the operation of the press,
A hydraulic cylinder 50 having a piston filled with a working fluid at a first set pressure, the piston being coupled to the bed and configured to act upon a load applied to the bed through the die during the molding operation of the press;
A first hydraulic pump 11 for supplying a working fluid to the hydraulic cylinder 50;
A first pipe 1 through which a working fluid flows from the first hydraulic pump to the hydraulic cylinder;
A branch which is branched from the first pipe 1 between the hydraulic cylinder 50 and the first hydraulic pump 11 and discharges the pressure fluid to the outside when the working fluid filled in the hydraulic cylinder exceeds the first set pressure; 1 relief valve 21;
The flow rate of the working fluid supplied from the first hydraulic pump 11 to the hydraulic cylinder 50 is disposed between the point where the first relief valve 21 branches in the first pipe 1 and the hydraulic cylinder 50. A flow rate control valve 22 which adjusts the piston of the hydraulic cylinder 50 to be disposed at a set up position and comprises a proportional control valve;
The accumulator in which the compressive gas is filled to a predetermined pressure, which is set according to the capacity of the press, is compressed to a second set pressure which is higher than the first set pressure and lower than the pressure at which the working fluid is pressurized in the hydraulic cylinder during the molding operation of the press 46;
A second pipe 2 branched from the first pipe 1 between the hydraulic cylinder 50 and the flow control valve 22 to communicate with the accumulator 50;
A check valve 23 provided between the first pipe 1 and the second pipe 2 to restrict the working fluid to flow only from the first pipe 1 to the second pipe 2; And
Control unit for controlling the operation of the shock absorber and inputting setting values for the operation of the shock absorber
It is configured to include,
In the preparatory operation of the press-molding operation, the first hydraulic pump 11 is operated to fill the hydraulic cylinder with pressurized working fluid to the hydraulic cylinder through the first pipe 1 at the first set pressure, and the piston is controlled by the flow control valve. Configured to be in the elevated position set by
In the molding operation of the press, the flow control valve 22 is closed, and when the piston of the hydraulic cylinder 50 is lowered by the molding operation of the press, the working fluid in the hydraulic cylinder 50 is discharged and passes through the check valve 23. Is introduced into the accumulator 46 through the second pipe 2 to compress the compressible gas of the accumulator,
A second hydraulic pump 17 for supplying a working fluid to the accumulator 46;
A third pipe connected between the second hydraulic pump 17 and the check valve 23 to the second pipe 2 to transfer the working fluid supplied from the second hydraulic pump 17 to the accumulator 46 ( 3);
A pressure sensor 36 branched to the third pipe 3 to measure the pressure of the working fluid flowing through the third pipe 3; And
A second relief for discharging the working fluid from the second hydraulic pump 17 to the outside when the pressure of the working fluid filled in the accumulator 46 reaches the second set pressure according to the measurement signal from the pressure sensor 36. Valve (31)
The shock absorber further configured to fill the accumulator (46) with a working fluid at a second set pressure prior to the preparatory operation of the shaping operation. The method according to claim 1,
It is arranged branching from the second pipe 2, and is opened when the pressure of the working fluid acting by the lowering of the piston of the hydraulic cylinder 50 in the forming operation of the press exceeds the second set pressure, thereby opening the second pipe 2 And a logic valve (29, 30) for discharging the working fluid from the outside. delete The method according to claim 1,
A third relief valve 27 branched between the flow rate control valve 22 and the hydraulic cylinder 50 and connected to the first pipe 1 and opened at an opening pressure higher than the second set pressure;
The opening pressure of the third relief valve (27) is set to a pressure that can cause breakage or failure of the shock absorber during the molding operation of the press.

Images