JPS5834201A - Charge control of accumulator - Google Patents

Abstract

PURPOSE:To reliably control pressure of gas and quantity of oil by regulating pressure of gas by means of a piston type accumulator which is integrated into a discharge circuit of a die casting machine or so at a point when a certain quantity of working oil is supplied in the accumulator. CONSTITUTION:A piston type accumulator 5 and a gas accumulator 6 are interconnected at respective tops. A level detector 19 which detects that a piston 5a is forced up to a position high enough in said accumulator 5 to discharge working oil is disposed at the top of or inside the accumulator 5. A solenoid change- over valve 20 is disposed in a circuit which supplies the working oil from a pump 1 to the bottom of the accumulator 6 and a pressure detector 21 is connected to the outflow side of said valve 20. If a pressure which is detected by the pressure detector 21 stands below a certain value after operation of the level detector 19, a controller 22 excites a solenoid (b) of the solenoid change- over valve 20 to supply the working oil to the bottom of the accumulator 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the filling of an accumulator in an injection circuit of a die-casting machine, etc., when hydraulic oil is supplied to the accumulator provided for high-speed injection every injection cycle. .

Conventionally, when using a combination of a piston type accumulator and a gas accumulator in the accumulator installed in the injection circuit of Guikasu, Thomasin, and extrusion presses, 1
For example, a circuit as shown in FIG. 1 is known.

In FIG. 1, 1 is a po/g, 2 is a motor, 3 is an injection cylinder, 4 is a switching valve for forward and backward movement of the injection/su/da, 5 is a piston type accumulator with a slidably built-in piston 5a, and 6 is a gas accumulator, 7 is a valve for high-speed injection, 8 is a
1 is a switching valve provided in a circuit that supplies hydraulic oil to the lower part of the gas accumulator 6, 9 is a pressure switch, 10 is a pressure gauge, 1
1 is a relief valve, 12 to 16 are on-off valves, 17 is a check valve, and 18 is a tank.

However, in the conventional device shown in Fig. 1,
When setting the gas pressure when the gas accumulator 6 is initially filled with gas, the on-off valve 14 is opened when changing the set gas pressure.

Sometimes the switching valve 8 is switched to supply hydraulic oil into the gas accumulator 6, but normally the on-off valve 14 is closed.
The switching valve 8 also shuts off the hydraulic oil.

Hydraulic oil is supplied to the accumulator for each injection cycle only to the piston type accumulator 5 with the on-off valve 12 kept open.

In these conventional devices,
As described in Publication No. 9405 and Japanese Patent Publication No. 54-30373, it is possible to reduce the volume of the piston type accumulator and shorten the filling time when filling the gas accumulator with nitrogen gas from a commercially available gas bottle. However, no consideration was given to changes in gas temperature.

That is, if the pressure of the gas such as nitrogen gas filled in the gas accumulator 6 is kept constant, then
Changes in proportion to temperature changes. That is, when Po is the pressure when the absolute temperature is To, and Pl is the pressure when the absolute temperature is Tl.

I p, =po ・- O becomes.

To start working at a temperature of 10 degrees, again.

The ambient temperature in steady state is about 50°C. Then, the pressure increases in accordance with this temperature change, and the amount of pressure change due to this temperature difference is approximately 1.14 times.

The impact on die-cast products is a value that cannot be ignored. Moreover, this change does not stabilize rapidly.

It changes over 30 to 60 shots from the start of work. Therefore, this causes a decrease in product yield.

Of course, in conventional devices, it is also conceivable to open and close the on-off valves 14 and 15 each time depending on the rise in temperature of the hydraulic oil and gas, and manually adjust the amount of oil in the gas cylinder each time. , it is virtually impossible to perform this adjustment in a two-manual manner every cycle, and it cannot be performed accurately.

The present invention eliminates these drawbacks and automatically adjusts the gas pressure to inject under stable injection conditions from the start of the second operation, thereby making it possible to improve product quality.

In the present invention, an accumulator that is a combination of a piston type accumulator and a gas accumulator is used. When the gas accumulator reaches the specified position, the pressure in the gas accumulator is detected.

The amount of hydraulic oil in the gas accumulator is controlled according to the detected pressure, and the gas pressure is automatically adjusted to a preset pressure.

Next, the present invention will be explained in detail with reference to an embodiment of an apparatus used in carrying out the method of the present invention shown in the two drawings. In addition,
In FIGS. 2 to 4, the same parts as those shown in FIG. 1 are designated by the same reference numerals as shown in FIG. 1, and the explanation thereof will be omitted.

In one embodiment shown in FIG. 2, the top of the piston-type accumulator 5 and the top of the gas accumulator 6 are connected to each other, and the top or midway of the piston-type accumulator 5 contains the necessary amount for injection into the piston-type accumulator 5. A position detection device 19 such as a magnetic switch is provided to detect when the piston 5a has come to a position where the amount of hydraulic oil is secured.

Located on the hydraulic oil supply side of the piston type cylinder 5.

A check valve 17a is provided on the pump 1 side of the on-off valve 12 that is always open during operation, and a check valve 17a is provided on the pump 1 side of the on-off valve 12, which is always open during operation.
In the circuit that supplies hydraulic oil to the bottom of the.

An electromagnetic switching valve 20 having solenoids a and b is provided.

A pressure detector 21 for detecting the pressure of the gas accumulator 6 was connected to the circuit between the electromagnetic switching valve 20 and the on-off valve 14. However, since the pressure detector 21 is for detecting the pressure in the gas accumulator 6,
It may be installed in the upper part of gas accumulator B or in the upper part where gas is sealed, or it may be installed in the upper part of gas accumulator B.
It may be installed at the bottom or lower part of the hydraulic oil seal.

Reference numeral 22 denotes a control device which receives an electrical input corresponding to the pressure detected by the pressure detector 21 and can appropriately excite and demagnetize the solenoids a and b of the electromagnetic switching valve 20 accordingly. In the electromagnetic switching valve 20, the gas accumulator 6
The hydraulic oil is supplied to the tank 18, and the hydraulic oil is discharged from the gas tank 18 into the tank 18. 23 is a switching valve 2 for unloading the pump 1.

Next, the accumulator filling control method and operation in the apparatus shown in FIG. 2 will be explained.

During the injection work, the on-off valves 12, 1 and 14 are always open, and the on-off valves 15 and 16 are always closed.

The electromagnetic switching valve 20 is closed as shown.

To start work, rotate pump 1 and open/close valve 12゜1.
4, the piston 5a in the piston type accumulator 5 approaches the upper limit, and the upper limit is detected by the position detection device 19. In this case, the upper limit position of the piston 5a means that when hydraulic oil is supplied into the piston type accumulator 5 and the piston 5a rises in each injection cycle, the supplied hydraulic oil is necessary for a predetermined injection. This is the position at which the piston 5a stops due to the operation of the two-position detection device 19 or other actions when a certain amount is secured, and this upper limit position may be in the middle of the piston type accumulator 5 or may be at the top. .

When the position detection device 19 of the piston type accumulator 5 is activated, an electrical signal is immediately sent to the control device 22, and the pressure detector 21 detects whether the pressure in the gas accumulator 6 at that time reaches the specified pressure or not. , the control device 22 makes a determination regarding the pressure.

When the pressure detected by the pressure detector 21 has not reached the specified pressure, the loading of the pump 1 is maintained as it is, and the solenoid b of the electromagnetic switching valve 2o is energized through the control device 22, so that the gas is transferred to the bottom of the gas accumulator 6. Supply hydraulic oil and maintain this state until the gas pressure reaches the specified pressure. and.

If the pressure detector 21 detects the specified pressure, solenoid b
is demagnetized, the switching valve 23 is operated, and the pump 1 is unloaded.

On the other hand, when the pressure detected by the pressure detector 21 is equal to or higher than the specified pressure, the switching valve 23 is operated to immediately anorod the pump, and the electromagnetic switching valve 2oer) solenoid a is energized, and the bottom of the gas accumulator 6 is The hydraulic oil is discharged to the tank 18 via the electromagnetic switching valve 2o, and when the gas pressure reaches the specified pressure, the solenoid a is demagnetized.

Of course, when the two-position detection device 19 is activated and the pressure detector detects the gas pressure, if the gas pressure is within the specified range, the electromagnetic switching valve 20 is not switched.

It operates in the same way as before. Also, as a specified pressure.

In terms of control, it goes without saying that it is better to set a certain range than to fix a single point and name.

In addition, in the above example, when the gas pressure has not reached the specified pressure,
When hydraulic oil is supplied to the gas accumulator 6, the hydraulic oil is also supplied to the bottom of the piston-type accumulator 5, but the same pressure is always maintained in both accumulators 5 and 6.

The piston 5a does not go down and hardly moves. In addition, even if the gas pressure exceeds the specified pressure and the bottom of the gas accumulator 6 is activated [-- when the gas is discharged into the tank 18 via the electromagnetic switching valve 20, the piston 5a will not go down due to the action of the check valve 17a. do not have. Therefore, even if the amount of hydraulic oil in the gas accumulator 6 is automatically adjusted and the gas pressure is adjusted after the two-position detection device 19 is activated.

The amount of hydraulic oil in the piston-type a4 chemulator 5 is maintained at a specified amount until the injection operation begins.

In another embodiment shown in FIG. 3, the check valve 1 in FIG.
A switching valve 24 for opening and closing is used instead of 7a.

When supplying hydraulic oil to the piston-type accumulator 5, it is made to flow, and when the position of the piston 5a is detected by the position detection device 19, the switching valve 24 is simultaneously switched and shut off as shown in the figure, and the pressure sensor 21 and the control By actuation of the device 22 and the electromagnetic switching valve 2o.

The same control as described above is performed. In the pressure detector 21 shown in FIG. 3, an example is shown in which pressure detectors 21a and 21b for upper limit detection and lower limit detection are provided separately.

In addition, in the embodiment shown in FIG. 4, a pump 1a for supplying hydraulic oil to the gas accumulator 6 is provided in addition to the pump 1 for operating the injection cylinder 6 and for supplying hydraulic oil to the piston type accumulator 5. Ta.

2a is a motor, and 25 is a switching valve for unloading the pump 1a.

In addition, if the piston-type Achiemulator 5 is connected to the pump 1 or injection cylinder B on the side where the hydraulic oil is supplied and the gas working side is connected to the Gas Achiemulator 5, it can be used even when it is upside down or in other situations. You can leave it installed.

In this way, in the present invention, the structure described in the claims is adopted, and the gas pressure of the accumulator is automatically adjusted in response to the temperature change without ignoring the temperature change of the hydraulic oil or gas. Moreover, since this adjustment can be made in response to temperature changes for each injection cycle, the temperature of the hydraulic oil or gas is still relatively low after 9 operations have started in die-casting machines, etc. Even when the oil pressure is low, not only the predetermined amount of oil in the piston accumulator can be obtained, but also the predetermined gas pressure can be reliably and easily obtained every time, so that quality products can be started promptly. and.

Even when the temperature of hydraulic oil etc. is relatively high.

The predetermined gas pressure and oil amount can be automatically and reliably and easily obtained, and high-quality products can always be obtained.

Note that the gas pressure is high when the hydraulic oil is completely filled.

It is low after injection ends and changes during one cycle.

In the present invention, the gas pressure is set using the point in time when a specified amount of hydraulic oil is supplied into the piston type accumulator as a reference point,
When the piston of the piston accumulator reaches a predetermined position and the hydraulic oil reaches a specified amount, gas pressure can be adjusted immediately, so gas pressure and oil amount can be controlled reliably. Of course, when the gas pressure reaches the specified pressure, the pump can be unloaded to save energy.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing an example of a conventional device. 2 to 4 are hydraulic circuit diagrams showing different embodiments of apparatus for carrying out the method of the present invention. 1.1a...Pump, 3...Injection cylinder, 4
, 8°23-25...Switching valve, 5...Piston type accumulator, 5a...Piston, 6...Gas accumulator, 7...Valve, 12-16...Opening/closing valve. 19...Position detection device, 20...Solenoid switching valve. 21...Pressure detector, 2ya...Control device Patent applicant Ube Industries Co., Ltd. No. 1 1N2 Figure 145g Procedural amendment (Method I) June 11, 1980 Commissioner of the Japan Patent Office 1 Indication of the case Japanese Patent Application No. 56-130062 Title of the invention Accumulator filling control method 6 Relationship with the case of the person making the amendment Patent applicant Postal code 755 1-12-32 Nishihoncho, Ube City, Yamaguchi Prefecture Telephone: 03 (5)
81) 3311 4 There is no date correction order for correction order. 5. Title of the invention in the application and specification to be amended; Claims in the specification; 2. Detailed explanation of the invention. 6. Contents of amendment (1) The amended application form is as attached. (The title of the invention of 21EJ'[lt is amended to "Achievement control method for filling the achievable unit." Page 2, line 16. "Filling" in page 6, line 9, page 7', line 10, page 7', line 6, and page 11, line 19, is corrected to "filling." Amended claims of Japanese Patent Application No. 130062/1982 When the required amount of hydraulic oil is secured, the pressure in the gas accumulator is detected, and the amount of hydraulic oil in the gas accumulator is controlled according to the detected pressure, so that the gas pressure is set in advance. Aquimulator filling control method that automatically adjusts to pressure 1 and above

Claims (1)

[Claims] Using an accumulator that is a combination of a piston type accumulator and a gas accumulator, supply hydraulic oil to the piston 7 type accumulator, and when the piston type accumulator reaches a position where the amount of hydraulic oil necessary for the next injection of the piston is secured. , an accumulator filling control method that detects the pressure of a gas accumulator, controls the amount of hydraulic oil in the gas accumulator according to the detected pressure, and automatically adjusts the gas pressure to a preset pressure. .