JPH1110309A - Method for controlling injecting force in die casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injecting force control method of a die casting machine which can change adjusting range of a metallic pressure given to molten metal into arbitrary range with extremely simple and easy method and can expand the utility of the machine. SOLUTION: In this injecting force control method of the die casting machine, an accumulator 10 connected in series with a piston type accumulator 10A and a gas accumulator 10B through a stop valve 20 at the intermediate, is connected with the head side of an injection cylinder 8 and the molten metal is injected and filled up into a cavity in the die 2 while controlling the advancing force of the injection cylinder 8. In such a case, when the metallic pressure given to the molten metal during injection intends to be high pressure, a stop valve 20 is made into the communicating state to increase the vol. at the head side of the piston type accumulator 10A. When the metallic pressure given to the molten metal during injection intends to be low pressure, the stop valve 20 is made into the close state to reduce the vol. at the head side of the piston type accumulator 10A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the injection power of a die casting machine, and more particularly, to a metal pressure adjustment range in which a desired metal pressure to be applied to a molten metal is determined by specifications of an injection cylinder, a plunger tip diameter, and the like. If you deviate,
The present invention relates to an injection power control method for a die casting machine capable of easily and easily changing a metal pressure adjustment range.

[0002]

2. Description of the Related Art A conventional injection device of a die casting machine has a function of adjusting a firing force in order to adjust a metal pressure of a molten metal to be cast into a mold cavity. However, in recent years, the demand for high quality of molded products has become more sophisticated, and not only are the cases of increasing the metal pressure to be high in order to remove the cavities of molded products, but also, for example, O
In some cases, such as thin large-sized products such as A floors, casting is performed at a low pressure, and the pressure range in which metal pressure is used with the same die casting machine has been widened. , Cannot cover the entire pressure range.

Therefore, as shown in FIG. 4, an accumulator 10 in which a piston type accumulator 10A and a gas accumulator 10B formed by a gas bottle 10b are connected in series is connected to an injection cylinder 8 to form a metal melt. Attempts have been made to expand the range of adjustment of the applied metal pressure.

In this case, the injection forward force Fh is π / 4 ·
D ² · Ph (D is the inner diameter of the injection cylinder, Ph is the pressure on the head side), whereas the injection limiting force Fr which is the retraction force is
Is π / 4 · (D ² −d ² ) · Pr (d is the diameter of the injection piston, Pr is the pressure on the rod side), so that the metal pressure Pm applied to the molten metal takes into account the injection power F = Fh−Fr Then, the following equation is obtained. Pm = F / (π / 4) · dm ² = D ² / dm ² · Ph- (D ² -d ² ) / dm ² · Ph where dm is the plunger tip diameter. It is.

[0005] In the equation, the injection cylinder inner diameter D, the injection piston diameter d, and the tip diameter dm are constants determined by mechanical specifications, and can be changed by the cylinder head pressure Ph and the cylinder rod pressure Pm. Normally, the metal pressure Pm is changed by operating the rod pressure adjusting valve 30 in FIG. 4 to change Pr.

[0006] As an actual example, for example, 350TO
In the example of N die casting machine, D = 180mm, d
= 120 mm, dm = 70 mm, Ph = 132 kgf /
When the pressure is set to cm ² , the metal pressure Pm is given by the following equation. Pm = 873−3.67 · Pr On the other hand, the adjustment range of the rod pressure Pr is Pr = 0 to 132k.
gf / cm ² , as a result, the adjustment range of the metal pressure is Pm = 389 to 873 kgf / cm ² , and the metal pressure Pm is set to 300 kgf / cm ² due to production reasons.
If it is desired to set it to ² , it is below the adjustment range, so it cannot be done as it is. In order to solve this, the gas in the piston ACC10A and the gas ACC10B is evacuated, the ACC charge pressure is changed to be low, and the head pressure Ph at the time of completion of filling is reduced (however, if the ACC capacity is sufficiently large, the ACC charge pressure However, it is possible to deal with this by simply changing only the ACC, but it requires a very large ACC and increases the cost).

In the case of a 350TON die-casting machine, the charge completion pressure is usually 155 kgf / cm ² and the head pressure Ph at the time of filling is 132 kgf / cm ² , but this charge completion pressure is changed to 110 kgf / cm ^2. If the head pressure Ph at the time of completion of filling is 94 kgf / cm
It becomes ² . In this case, the metal pressure Pm is given by the following equation. Pm = 674-3.67 · Pr... Therefore, in order to set the metal pressure Pm to 300 kgf / cm ² , Pr = 88 kgf / cm ² from the formula, and the molded product is formed on the OA floor. When the metal pressure Pm is 3
Casting becomes possible under the condition of 00 kgf / cm ² .

[0008]

However, according to the above-mentioned method, the piston A is required each time casting with a low metal pressure is performed.
When gas is released from the CC and gas bottles, and conversely, when returning to casting with a high metal pressure, it is necessary to replenish the gas every time, which not only complicates the operation but also increases the gas consumption. There was a problem from the viewpoint of energy saving.

[0009]

According to the first aspect of the present invention, a piston type accumulator and a gas accumulator are connected in series with a stop valve interposed therebetween. An injection power control method for a die casting machine for injecting and filling a molten metal into a mold cavity while controlling a forward force of an injection cylinder by connecting an accumulator formed as described above to a head side of an injection cylinder. When it is desired to increase the metal pressure to be applied to the molten metal, the stop valve is opened to increase the volume on the head side of the piston type accumulator, and when it is desired to reduce the metal pressure to be applied to the molten metal during injection, the stop is performed. The volume of the piston type accumulator on the head side is reduced by closing the valve.

In the second invention, the accumulator, which is formed by connecting a piston type accumulator and a gas accumulator in series with a stop valve interposed therebetween and connected in series, is connected to the head side of the injection cylinder, so that the forward force of the injection cylinder is increased. A method of controlling the injection power of a die casting machine for injecting and filling a molten metal into a mold cavity while controlling the injection pressure, wherein a desired metal pressure to be applied to the molten metal during injection is a cylinder diameter of an injection cylinder, a rod diameter, and a head. Pressure, the rod pressure, the plunger tip diameter, etc., when the adjustment range of the metal pressure is lower, the stop valve is closed and the head side volume of the piston type accumulator is reduced, thereby lowering the adjustment range of the metal pressure. Was not more than the desired metal pressure.

Further, in the third invention, a single piston type accumulator and a plurality of gas type accumulators are combined, and the plurality of gas accumulators have the same capacity (the same specification) or different capacity. age,
It was connected with a stop valve in between.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first aspect of the present invention, an accumulator comprising a piston type accumulator and a gas accumulator connected in series with a stop valve interposed therebetween and connected in series is connected to the head side of the injection cylinder. An injection power control method for a die-casting machine that injects and fills a molten metal into a mold cavity while controlling a forward force of an injection cylinder, wherein the metal pressure to be applied to the molten metal during injection is set to be high. When it is desired to increase the volume on the head side of the piston type accumulator by connecting the stop valve to the communicating state and to reduce the metal pressure to be applied to the molten metal during injection, the stop valve is closed and the head side of the piston type accumulator is closed. Because the volume has been reduced, without venting or refilling, Opening and closing operation of the top valve only becomes possible to change the adjustment range of the metal pressure at.

According to the second aspect of the invention, the accumulator formed by connecting a piston type accumulator and a gas accumulator in series with a stop valve interposed therebetween and connected in series is connected to the head side of the injection cylinder, and the forward force of the injection cylinder is increased. A method of controlling the injection power of a die casting machine for injecting and filling a molten metal into a mold cavity while controlling the injection pressure, wherein a desired metal pressure to be applied to the molten metal during injection is a cylinder diameter of an injection cylinder, a rod diameter, and a head. Pressure, the rod pressure, the plunger tip diameter, etc., when the adjustment range of the metal pressure is lower, the stop valve is closed and the head side volume of the piston type accumulator is reduced, thereby lowering the adjustment range of the metal pressure. Lower than the desired metal pressure, the lower limit of the metal pressure adjustment range is easily and easily reduced. Door can be, it is possible to lower the casting operation of the metal pressure.

According to a third aspect of the present invention, a single piston type accumulator and a plurality of gas type accumulators are combined, and the plurality of gas accumulators have the same capacity (the same specification) or different capacity. Since the stop valves are interposed and connected in the middle, the opening and closing of each stop valve is arbitrarily selected, so that the gas volume selection region of the entire accumulator is greatly expanded, and the adjustment range of the metal pressure can be selected in a wider range.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 relate to an embodiment of the present invention,
1 is a configuration diagram of an injection device of a die casting machine, FIG. 2 is a graph showing a correlation between an accumulator pressure and an injection forward stroke, and FIG. 3 is a configuration diagram of an accumulator showing another embodiment.

As shown in FIG. 1, a piston type accumulator 10A and a gas accumulator 10B formed by a gas bottle 10b are connected in series to the head side of an injection cylinder 8 constituting an injection device of the die casting machine 1. The accumulator 10 is connected, and a stop valve 20 is provided between the piston type accumulator 10A and the gas accumulator 10B. The injection piston 6 of the injection cylinder 8 is connected to the plunger tip 4 which slides in the injection sleeve 3 via the coupling 5 and moves forward and backward as shown in FIG. The molten metal stored in the injection sleeve 3 is injected and filled into a mold cavity (not shown) of the mold 2.

Die casting machine 1 configured as described above
, P ₁ : accumulator charge pressure (kgf / cm ² ) V ₁ : gas volume at the time of completion of accumulator charge (liter) Ph: injection cylinder head pressure at the time of completion of filling Vh: gas volume at the time of completion of injection and filling ( Liter) ΔV: volume of gas discharged from the accumulator during injection (liter) k: polytropic exponent Injection cylinder head pressure Ph when filling is completed
Becomes the following equation. Ph = (V ₁ / Vh) ^k · P ₁ ············ Ph = [1 / (1 + ΔV / V ₁ )] ^k · P ₁ ·, considering that Vh = V ₁ + ΔV ... Considering the formula, ΔV and k are constants, and P ₁ and V ₁ can be changed.

A method of changing the accumulator charge pressure P ₁ by degassing the accumulator 10 or conversely replenishing the gas by changing the accumulator charge pressure P ₁ among the two changing elements P ₁ and V ₁ is known in the prior art. This is the method described.

On the other hand, the method of the present invention
A method of changing the gas volume V ₁ of the time charging completion,
As a simplest method for this purpose, a stop valve 20 is provided between the piston type accumulator 10A and the gas accumulator 10B, and the stop valve 20 is closed.
0A gas chamber volume v ₁ and gas bottle 10b volume v ₂
The gas volume V ₁ was the sum of the, and to achieve the object by reducing only the volume v ₁ of the gas chamber of the piston accumulator 10A.

That is, when V ₁ is reduced in the equation,
Δ / V ₁ increases, and the denominator in parentheses in the equation increases. As a result, the value in parentheses decreases, and the injection cylinder head pressure Ph at the completion of filling decreases. Therefore,
As shown in FIG. 2, even if the ACC charge completion pressure is constant (155 K, K = kgf / cm ^{2 in the example} ),
The pressure at the time of actually generating the injection output, that is, the head pressure of the injection cylinder is set to 100K by closing the stop valve 20.
Will decrease.

Thus, the piston type accumulator 1
By selecting the ratio of gas volume v ₂ of the gas volume v ₁ and the gas bottle 10b which remains 0A, it can be optimally determined adjustment width.
In the case of the 350 TON die casting machine, in the case of the N mode (stop valve is open), the back pressure (rod side pressure) Pr is 98.
If K, a metal pressure of 300K can be obtained.

FIG. 3 is a configuration diagram of an accumulator showing another embodiment of the present invention. FIG. 3 (a) shows a plurality of gas accumulators 10B having the same capacity with respect to a single piston type accumulator 10A. In FIG. 3B, a plurality of gas accumulators 10B having different capacities are arranged. FIG. 3 (a),
(B) In any case, the stop valves 20, 20, 2
,... Of the entire accumulator 10 in the fully open state, v ₁ + v ₂ +... Since the gas volume v _x is expanded over a wide range, the adjustment range of the metal pressure Pm is greatly expanded accordingly.

[0023]

As described above, according to the method of the present invention, the adjustment range of the metal pressure applied to the molten metal can be changed to an arbitrary range by an extremely simple and easy method. Sex expands.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an injection device of a die casting machine according to an embodiment of the present invention.

FIG. 2 is a graph showing a correlation between an accumulator pressure and an injection advance stroke according to the embodiment of the present invention.

FIG. 3 is a configuration diagram of an accumulator according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of an injection device of a conventional die casting machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Die-casting machine 2 Die 3 Injection sleeve 3a Supply port 4 Plunger tip 5 Coupling 6 Injection piston 8 Injection cylinder 10 Accumulator (whole) 10A Piston accumulator 10B Gas accumulator 10b Gas bottle 20 Stop valve 30 Rod pressure regulating valve 40 Check valve D injection cylinder inside diameter d injection piston diameter dm plunger tip diameter P accumulator pressure Ph injection cylinder head pressure Pr injection cylinder rod pressure Pm metal pressure V ₁ gas volume ΔV during gas volume Vh injection filling completion during accumulator charging completion Gas volume discharged from accumulator during injection v ₁ Gas volume remaining in piston type accumulator v ₂ Gas volume of gas bottle k Polytropic index

Claims (3)

[Claims] An accumulator comprising a piston-type accumulator and a gas accumulator connected in series with a stop valve interposed therebetween and connected in series to the head side of the injection cylinder to control the forward force of the injection cylinder while controlling the molten metal. The injection power of a die casting machine for injecting and filling into the mold cavity, when it is desired to increase the metal pressure to be applied to the molten metal during the injection, the stop valve is in a communicating state and the head side of the piston type accumulator When it is desired to increase the volume of the metal and to reduce the metal pressure to be applied to the molten metal during injection, the stop valve is closed so that the volume of the piston type accumulator on the head side is reduced to control the firing force of the die casting machine. Method. An accumulator comprising a piston type accumulator and a gas accumulator connected in series with a stop valve interposed therebetween and connected in series to the head side of the injection cylinder to control the forward force of the injection cylinder while controlling the molten metal. A method of controlling the injection power of a die casting machine for injecting and filling a mold cavity into a mold cavity, wherein a desired metal pressure to be applied to the molten metal during injection is determined by a cylinder diameter of an injection cylinder, a rod diameter, a head pressure, a rod pressure, and a plunger. When the adjustment range of the metal pressure determined by the tip diameter or the like is smaller than the desired metal pressure, the stop valve is closed and the volume of the piston type accumulator on the head side is reduced, so that the lower limit value of the adjustment range of the metal pressure is equal to or less than the desired metal pressure. Power control method of die casting machine. 3. The accumulator is formed by combining a piston accumulator with a plurality of gas accumulators having the same capacity or different capacities as one piston type accumulator, and connecting and interposing a stop valve in the middle. 3. A method for controlling the output of a die casting machine according to claim 2.