JPH1113706A - Hydraulic control circuit and hydraulic forming machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control circuit to vary a flow rate and the pressure of working oil fed to a hydraulic actuator and simplify constitution of a pump unit and reduce size and to provide a forming machine utilizing the hydraulic control circuit. SOLUTION: This hydraulic control circuit comprises an air hydro converter 11 (a sealed container); a high pressure air feed source 14 (a pressurized air feeding means) to feed a pressurized air to the air hydro converter 11; a route Lf1 (a first route) to interconnect the air hydro converter 11 and a double acting hydraulic cylinder (a hydraulic actuator); a pump unit 12 (a pressurizing means) to pressurize working oil FL; a route Lf3 (a second route) to interconnect the pump unit 12 and the double acting hydraulic cylinder 2; and a cutoff valve 16 (a route switching means) to vary a connection state between the route Lf1 or the route Lf3 and the double acting hydraulic cylinder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control circuit for controlling a hydraulic actuator and a hydraulic forming machine equipped with the hydraulic control circuit, and uses a pressurized gas to increase the flow rate of hydraulic oil for driving the hydraulic actuator. Related to enabling technologies.

[0002]

2. Description of the Related Art FIG.
FIG. 2 is a diagram schematically illustrating a main configuration of a hydraulic circuit and a hydraulic circuit.
In FIG. 2, reference numeral 101 denotes a molding die, which is a hydraulic molding machine 10.
0, and a movable mold 101B that moves in the vertical direction by a hydraulic cylinder 102 in this prior art.

The arrangement of the fixed mold 101A and the movable mold 101B is such that, as shown in FIG.
The configuration is not limited to the configuration in which 1B is located below, and there are actually configurations in which the fixed type and the movable type are arranged in the horizontal direction, and configurations in which the movable type is arranged above.

There are various molding methods that can be performed by the hydraulic molding machine 100, and there is no particular limitation. For example, a sheet material (for example, a sheet material such as a metal plate or a nonwoven fabric) is pressed. Various molding methods such as molding, molding of a resin material, and die casting can be adopted. Here, description will be made assuming that the hydraulic forming machine 100 performs press forming of a sheet material.

The operation of the hydraulic forming machine 100 at the time of molding will be described.
01, and the fixed mold 101A and the movable mold 10
Work W as sheet material (sheet-like material) during 1B
Supply.

Then, the movable mold 101B is stroked at a high speed to a position P102 at which the limit switch 104 is switched (idling stroke Sv1). From the position P102 to a position P103 where the mold is closed, a low pressure and a high pressure are generated. The work W is formed by the stroke Sp.

[0007] Thereafter, the movable mold 101B is stroked at a high speed (idling stroke Sv2) from the mold closed position P103 to the position P101 to open the mold, and the formed work W is taken out and, if necessary, the mold is cleaned and cleaned. Perform lubrication work, etc.

Next, the configuration of the hydraulic circuit 110 for operating the hydraulic cylinder 102 will be described. 111 is a hydraulic circuit 11
0 is a hydraulic tank that supplies and stores 0 hydraulic oil, 112 is a pump unit that pressurizes and supplies hydraulic oil from the hydraulic tank 111,
Reference numeral 113 denotes a closed center type 4-port 3-position switching solenoid valve (hereinafter, referred to as a hydraulic control valve 113).
The high-speed stroke operation of the hydraulic cylinder 102 is switched.

The pump unit 112 includes an electric motor 112C for driving the pump, a first-stage pump 112A having a large discharge oil amount at a low discharge pressure, and a second-stage pump 112B having a small discharge oil amount at a high discharge pressure. It is a step discharge type,
The hydraulic oil discharged by the stage pump 112A is supplied to the hydraulic control valve 113.

The hydraulic control valve 113 has solenoids 113a and 113b at both ends thereof.
By moving c, 113d to the center portion 113e, the idle feeding strokes Sv1, Sv of the hydraulic cylinder 102 are performed.
2 when performing (2) the high speed rise (the spool 113c moves to the center portion 113e) and the high speed
Moves to the center part 113e).

The hydraulic oil discharged by the second-stage pump 112B is supplied to the hydraulic cylinder 102 with a pressure stroke Sp.
Is supplied to the high-pressure circuit 114 for controlling the high-pressure hydraulic oil required for the operation, and is supplied to the hydraulic cylinder 102 in a state where the pressure and the oil amount are controlled with high precision.

The paths connecting the components are divided into a path for a high-speed stroke and a path for a pressure stroke.

The high-speed stroke path includes a path L101 connecting the hydraulic tank 111 and the pump unit,
A path L102 connecting the first-stage pump 112A and the hydraulic control valve 113, a path L103 connecting the high-speed ascending port of the hydraulic control valve 113 and a feed port of the hydraulic cylinder 102,
High-speed descent port of hydraulic control valve 113 and hydraulic cylinder 10
L104 connecting the return port of the second, hydraulic control valve 1
A route L105 connecting the drain port 13 and the return side of the hydraulic tank 111 is provided.

A path L1 connecting the second-stage pump 112B and the high-pressure circuit 114 is used as a path for the pressurizing stroke.
06, a path L107 connecting the output port of the high-pressure circuit 114 and the path L103 (or the feed port of the hydraulic cylinder 102), a drain port of the high-pressure circuit 114 and the path L1
05 (return side of the hydraulic tank 111)
108 are provided.

Reference numeral 114a denotes a check valve for preventing the pressure inside the high-pressure circuit 114 from excessively rising, and 115 denotes a pressure sensor for detecting the pressure of the output path L105 of the high-pressure circuit 114.

[0016]

Accordingly, in the hydraulic forming machine 100 having the structure as shown in FIG.
Although the movable mold 101B is moved by the stroke of No. 2, in order to shorten the cycle time and to perform a high-speed stroke in the pneumatic-feed stroke area, no pressure is required, but a large flow of hydraulic oil is supplied. In the pressure stroke region, the flow rate may be small, but it is necessary to supply high-pressure hydraulic oil. Therefore, the two-stage discharge pump unit 1 having the first-stage pump 112A and the second-stage pump 112B
12, it is necessary to switch and use each pump, which causes a problem that the configuration of the pump unit is complicated and large.

For example, if the diameter of the hydraulic cylinder 102 is 14
0 (mm), the range of the high-speed stroke is set to 270 (mm), in order to perform a high-speed stroke in 2 seconds, the discharge oil amount of the first stage pump 112A needs about 124 liters per minute. Become.

As an example of a pump that satisfies this performance, a required horsepower of 3 to 10 (Kw) is required under a use condition of a discharge pressure of 5 (kgf / cm ² ), and the weight of the electric motor is 50 (Kg) or more. The weight of the pump alone is 50 (K
g) or more, resulting in an increase in size.

Alternatively, it is conceivable to employ a variable displacement pump capable of changing the pressure and the flow rate, but the price is expensive and the durability of the pressure setting mechanism for frequently changing the discharge pressure is ensured. There are problems such as difficulty.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to make it possible to change the flow rate and pressure of hydraulic oil supplied to a hydraulic actuator and to simplify a pump unit. It is an object of the present invention to provide a hydraulic control circuit having a simple configuration and capable of being downsized, and to provide a molding machine using the hydraulic control circuit.

[0021]

According to the present invention, there is provided a hydraulic pressure control circuit for supplying hydraulic oil for operating a hydraulic actuator, wherein the sealed container stores the hydraulic oil. Pressurized gas supply means for supplying pressurized gas to the sealed container, a first path connecting the sealed container and a hydraulic actuator, pressurizing means for pressurizing hydraulic oil, A second path connecting the actuator and a path switching unit that changes a connection state between the first or second path and the hydraulic actuator are provided.

With this configuration, the hydraulic actuator is actuated by the operating oil discharged from the sealed container to the first path by the pressurized gas sent to the sealed container, and the second path is pressurized by the pressurizing means. The operation of the hydraulic actuator by the hydraulic oil discharged to the controller can be performed by selecting a path by the path switching means.
Therefore, hydraulic oil according to the flow rate and pressure of the pressurized gas into the sealed container is supplied from the first path, and hydraulic oil according to the discharge amount of the pressurizing means and the pressure is supplied from the second path. By doing so, the operating speed and the pressing force of the hydraulic actuator can be changed.

A control mode for connecting the first path to the hydraulic actuator by the path switching means and driving the pressurized gas supply means to enable a high-speed operation of the hydraulic actuator; And a control mode for connecting the second path to the hydraulic actuator and driving the pressurizing means to enable a pressurizing operation of the hydraulic actuator.

According to this, it is possible to select the high-speed operation or the pressurizing operation by changing the flow rate and the pressure of the working oil supplied to the hydraulic actuator.

Further, the hydraulic actuator is a double-acting hydraulic cylinder having at least two chambers separated by a piston, and the first and second paths are connected to one chamber of the double-acting cylinder. A third path for supplying a pressurized gas from the pressurized gas supply means is connected to the other chamber of the moving cylinder.

According to this, a pressurized gas is supplied via the third path to the other chamber which does not need to supply hydraulic oil to move the piston, and the piston is directly moved by the pressure of the pressurized gas. It can be moved to operate the hydraulic actuator.

A hydraulic forming machine is characterized by comprising a hydraulic actuator, a movable member driven by the hydraulic actuator, and the above-described hydraulic control circuit for operating the hydraulic actuator.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a main structure of a hydraulic forming machine 1 according to an embodiment to which the present invention is applied, and hydraulic control for operating a double-acting hydraulic cylinder 2 as a hydraulic actuator provided in the hydraulic forming machine 1. FIG. 3 is a diagram schematically illustrating a circuit 3.

In FIG. 1, reference numeral 4 denotes a molding die, which is a fixed die 4A fixed at a predetermined position of the hydraulic molding machine 1, and a movable die 4B which is moved up and down by a double-acting hydraulic cylinder 2 in this embodiment. It has.

The arrangement of the fixed mold 4A and the movable mold 4B is not limited to the configuration in which the fixed mold 4A is located above and the movable mold 4B is located below as shown in FIG. A configuration in which the movable die is disposed in a horizontal direction or a configuration in which a movable die is disposed above may be employed.

There are various molding methods which can be performed by the hydraulic molding machine 1. There are no particular limitations on the molding method. For example, a sheet material (for example, a sheet material such as a metal plate or a nonwoven fabric) is pressed. Various molding methods such as molding, molding of a resin material, and die casting can be adopted. Here, the description will be made on the assumption that the hydraulic forming machine 1 performs press forming of a sheet material.

The operation of the hydraulic molding machine 1 at the time of molding will be described. First, the movable mold 4B is lowered to the widely opened position P1, and a sheet material (sheet-like material) is placed between the fixed mold 4A and the movable mold 4B in this state. Is supplied.

Then, the movable type 4B is connected to the limit switch 5
The workpiece W is formed by a high-speed stroke upward to the position P2 where the is switched (idling stroke Sv1), and from the position P2 to the position P3 where the mold is closed, the work W is formed by the pressurizing stroke Sp which generates a low pressure and a high pressure.

Thereafter, from the position P3 where the mold is closed to the position P
1, the movable mold 4B is stroked downward at high speed (idle-feed stroke Sv2) to open the mold, and the molded work W is taken out, and if necessary, the mold is cleaned and lubricated.

Next, the configuration of the hydraulic control circuit 3 for operating the double-acting hydraulic cylinder 2 will be described. 11 is a hydraulic control circuit 3
An air-hydro converter as a sealed container for storing the hydraulic oil FL, a pump unit 12 as a pressurizing means for pressurizing the hydraulic oil FL from the air-hydro converter 11, and a state in which the pressure and oil amount are controlled with high precision. A high-pressure circuit for controlling the high-pressure hydraulic oil FL required when the pressurizing stroke Sp is supplied to the double-acting hydraulic cylinder 2 to perform the pressurizing stroke Sp;
14 is a high-pressure air supply connected to a compressor (not shown) as a pressurized gas supply means, and 15 is a high-pressure air supply 1
4 is a control valve for controlling the pressurized gas, 16 is a shutoff valve as a path switching means, and 17 is a hydraulic oil F from a high pressure circuit 13.
This is a pressure sensor that detects the pressure of L.

The double-acting hydraulic cylinder 2 is a hydraulic chamber 2 which is one chamber partitioned by a piston 2a inside the cylinder chamber.
c, a hydraulic port 2d for supplying and discharging hydraulic fluid FL, and a pneumatic port 2f for supplying and discharging high-pressure air as pressurized gas to a pneumatic chamber 2e, which is the other chamber, and a piston that moves in a cylinder chamber. The movable die 4B is moved by the piston rod 2b connected to the movable die 4a.

The air-hydro converter 11 accumulates hydraulic oil FL inside the sealed container and controls the control valve 15.
, High-pressure air (about 5 to 10 kgf / cm ² ) flows from the high-pressure air supply source 14 into the air port 11a and discharges the hydraulic oil FL from the hydraulic oil port 11b.

Although the pressure of the hydraulic oil FL is low in accordance with the pressure of the high-pressure air, the discharge amount of the hydraulic oil FL can be easily increased by increasing the amount of the high-pressure air flowing into the air-hydro converter 11. It is possible to Further, it is also possible to maintain the inside of the hydroconverter 11 in a pressure accumulating state by the pressure of the high-pressure air and discharge the hydraulic oil FL at a stretch.

The pump unit 12 has a high pressure (for example, about 100 kgf / cm ^{2 in} this embodiment) required for performing the pressurizing stroke Sp of the double-acting hydraulic cylinder 2.
However, since the discharge amount may be small, it is possible to use a small pump with a motor (motor horsepower: 0.75 kW, total weight of the motor and the pump: 30 kg).

The high-pressure circuit 13 is provided with a pressure control (not shown) to enable the pressure and oil amount to be supplied to the double-acting hydraulic cylinder 2 in a state where the pressure and oil amount are controlled with high precision by a command from the main body of the hydraulic molding machine 1. Means and flow control means are provided.

The surplus of the high-pressure hydraulic oil FL supplied from the pump unit 12 is returned to the air-hydro converter 11 via a path Lf4. Reference numeral 13a is a check valve for preventing the pressure inside the high-pressure circuit 13 from excessively rising.

Next, a description will be given of a route for connecting each component device. The path includes a pneumatic path and a hydraulic path.
Path for high-speed stroke as a path for
There is a pressurizing stroke path as a second path through which the high-pressure hydraulic oil pressurized by the pump unit 12 flows through the pressurizing stroke.

The pneumatic path includes a high-pressure air supply source 14.
A path La1 connecting the air port 11a of the air-hydro converter 11 (via the control valve 15) to the air pressure port 2f of the double-acting hydraulic cylinder 2 and the high-pressure air supply source 14 (via the control valve 15). A route La2 is provided as a third route.

The hydraulic path includes a path Lf1 connecting the hydraulic oil port 11b of the air-hydro converter 11 and the hydraulic port 2d of the double-acting hydraulic cylinder 2, and a hydraulic oil port 1
A path Lf2 connecting the high-pressure circuit 13 to the high-pressure circuit 13, a path Lf3 connecting the high-pressure circuit 13 to the hydraulic port 2d, and a path Lf4 serving as a return path of the hydraulic fluid FL from the high-pressure circuit 13 are provided. Route, route Lf
Reference numeral 3 functions as a pressure stroke path.

Further, a shutoff valve 16 is provided in the middle of the path Lf1, and a pump unit 12 is provided in the middle of the path Lf2.

With the hydraulic control circuit 3 having such a configuration,
The operation control of the double-acting hydraulic cylinder 2 can be performed as follows. It is assumed that the control of each component device is controlled by a control unit (not shown) provided in the hydraulic molding machine 1 (specifically, an electric control circuit that performs sequence control, CPU control, and the like).

(Pneumatic Feeding Stroke Sv1) When performing the pneumatic feeding stroke Sv1 of the double-acting hydraulic cylinder 2, high-pressure air is sent from the high-pressure air supply source 14 to the air-hydro converter 11 and the shut-off valve 16 is opened. Hydraulic oil F
L is sent to the hydraulic chamber 2c, and the piston 2a is raised at a high speed (a control mode enabling high-speed operation of the hydraulic actuator).

(Pressure Stroke Sp) The movable die 4B performs a pressure stroke Sp from the position P2 to the closed position P3 when the movable die 4B strokes at a high speed to the position P2 and the limit switch 5 is switched. . At this time, the shutoff valve 16 is closed and the underpressure is reduced to the high pressure circuit 1.
The molding is supplemented by the pump unit 12 through 3 (control mode enabling the pressurizing operation of the hydraulic actuator).

(Non-conveying stroke Sv2) When performing the non-conveying stroke Sv2 after the completion of molding, the high-pressure air supply source 1
4 sends high-pressure air to the pneumatic chamber 2e and the shut-off valve 16
Is opened to lower the piston 2a at a high speed (a control mode enabling high-speed operation of the hydraulic actuator).

Therefore, when performing the idle feeding strokes Sv1 and Sv2, the high pressure air supplied from the high pressure air supply source 14 can move the piston 2a at high speed, so that the discharge flow rate of the pump unit 12 is increased. There is no need, and a small pump unit 12 can be used.

Since the pressure stroke Sp has a small stroke amount, it is not necessary to increase the flow rate of the hydraulic oil FL.
Since high pressure is required, the pump unit 12 is of a high pressure / low discharge flow rate type.

Since the hydraulic control circuit 3 is constructed by combining both hydraulic and pneumatic control circuits as described above, it should be called a hydraulic / pneumatic control circuit to be precise. Since the working oil pressurized by the pump unit 12 is necessary for the molding by the double-acting hydraulic cylinder 2,
It is simply called “hydraulic control circuit”.

[0053]

According to the present invention, the pressurized gas of the pressurized gas supply means and the hydraulic oil pressurized by the pressurizing means can be used as power for operating the hydraulic actuator,
High-speed operation and pressurizing operation of the hydraulic actuator can be performed as desired.

The pressurizing means does not need to discharge a large flow of hydraulic oil in order to operate the hydraulic actuator at high speed.
A small one can be adopted.

Therefore, when this hydraulic control circuit is applied to a hydraulic actuator used in a molding machine, for example, the molding cycle is increased by increasing the speed of closing and opening the mold, which requires large output by hydraulic pressure and high-speed operation. Can be shortened.

By the control means, it is possible to select the high-speed operation or the pressurizing operation by changing the flow rate and pressure of the hydraulic oil supplied to the hydraulic actuator.

When the hydraulic actuator is a double-acting hydraulic cylinder, pressurized gas is supplied via the third path to the other chamber which does not need to supply hydraulic oil to move the piston. The hydraulic actuator can be operated by directly moving the piston by the pressure of the pressurized gas.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a main part of a hydraulic control circuit and a molding machine according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a main part of a conventional hydraulic control circuit and a molding machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hydraulic molding machine 2 Double-acting hydraulic cylinder (hydraulic actuator) 2a Piston 2b Piston rod 2c Hydraulic chamber (one chamber) 2d Hydraulic port 2e Air chamber (other chamber) 2f Pneumatic port 3 Hydraulic control circuit 4 Mold 4A Fixed Mold 4B Movable type 11 Air-hydro converter (sealed container) 11a Air port 11b Hydraulic oil port 12 Pump unit (pressurizing means) 13 High-pressure circuit 14 High-pressure air supply source (pressurized gas supplying means) 15 Control valve 16 Shut-off valve (path) (Switching means) 17 Pressure sensor FL Hydraulic oil La1, La2, Lf1, Lf2, Lf3, Lf4 Path P1, P2, P3 Position Sv1, Sv2 Empty feeding stroke Sp Pressing stroke W Work

Claims (4)

[Claims] 1. A hydraulic control circuit for hydraulic oil supplied to operate a hydraulic actuator, comprising: a sealed container storing hydraulic oil; pressurized gas supply means for feeding a pressurized gas into the sealed container; A first path connecting the sealed container and a hydraulic actuator, a pressurizing unit for pressurizing hydraulic oil, a second path connecting the pressurizing unit and the hydraulic actuator, the first or the second A hydraulic control circuit comprising: a path switching unit configured to change a connection state between a path and the hydraulic actuator. 2. A control mode in which a first path and a hydraulic actuator are connected by the path switching means, and a control mode in which the pressurized gas supply means is driven to enable high-speed operation of the hydraulic actuator; 2. The control device according to claim 1, further comprising: a control mode that connects the second path to a hydraulic actuator, and drives the pressurizing device to enable a pressurizing operation of the hydraulic actuator. 3. Hydraulic control circuit. 3. The hydraulic actuator is a double-acting hydraulic cylinder having at least two chambers separated by a piston, connecting the first and second paths to one chamber of the double-acting cylinder, 3. The hydraulic control circuit according to claim 1, wherein a third path for supplying the pressurized gas from the pressurized gas supply unit is connected to the other chamber of the moving cylinder. 4. A hydraulic system comprising: a hydraulic actuator; a movable member driven by the hydraulic actuator; and the hydraulic control circuit according to claim 1 for operating the hydraulic actuator. Molding machine.