JPS5914303B2 - die casting machine injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection device for a die-casting machine, and more specifically, the present invention relates to an injection device for a die-casting machine, and more specifically, it is capable of quickly switching to high-speed injection, that is, starting up at the time of high-speed switching, and is capable of adjusting the flow rate, That is, the present invention relates to an injection device for a die-casting machine in which a high-speed injection speed can be set reliably and easily.

In general, the injection device of a die-casting machine is configured such that an accumulator is installed on the head end side of the injection cylinder, a check valve is installed in a passage connecting the accumulator and the head end side, and the opening and closing of this check valve is controlled by a four-way switching valve. Ta.

Figure 1 shows a conventional device, where 1 is the valve body, 2 is a check valve that doubles as an on-off valve and a throttle valve for flow rate adjustment, 3 is a bundle for opening adjustment, and 4 is a valve opening/closing valve. It is a four-way switching valve.

The inlet of the valve body 1 is connected to the accumulator, and the outlet is connected to the head side of the injection cylinder.

In the illustrated state, the bundle 3 is located on the rear side of the check valve 2.
The check valve 2 is closed because the accumulator pressure is also acting on the side, and if the four-way switching valve 4 is switched, the rear side of the check valve 2 will be connected to the tank 5, so the check valve 2 will be opened by the accumulator pressure. .

In that case, the check valve 2 opens according to the opening degree set by the operation of the bundle 3.

In the device shown in FIG. 1, when the check valve 2 is closed and high pressure is acting on the rear side of the check valve 2, the sliding between the outer circumferential side of the check valve 2 and the inner surface of the valve body 1 In the moving parts,
There is a drawback that a large amount of pressure oil leaks from the rear side of the check valve 2 toward the outlet.

As a result, it may become difficult to control the low injection speed of the injection cylinder, or the injection cylinder may attempt to move forward when stopped.

In addition, since the same valve serves as the opening/closing valve and the throttle valve, the throttle part at the tip of the check valve 2 is made longer in order to maintain linearity between the bundle opening and the speed of oil passing through the valve. Therefore, when the check valve 2 starts to open, the oil passage area increases relatively slowly, resulting in poor high-speed start-up characteristics.

The injection cylinder is constructed such that, as shown in the diagram in FIG. 2, the injection cylinder is configured to eject at a low speed during the initial stage of its operation, and to perform high-speed injection after a predetermined period of time.

Conventionally, the switching signal of the four-way switching valve 4 that operates the check valve 2 provided in the passage connecting the accumulator and the head end side of the injection cylinder is connected to a contact provided on the rond of the injection cylinder and a predetermined contact point. It was emitted by contact with the Limisoto Inchi LS installed at the location.

However, in the past, in order to perform high-speed injection, the check valve 2 described above was made large, and in order to open the large check valve 2 quickly, the four-way switching valve 4 was also large.

However, the large four-way switch had a slow switching speed, and since it was necessary to release a large amount of oil to the tank 5 through the four-way switching valve 4 to open the check valve, the opening speed was slow.

Therefore, as shown in Fig. 2, it takes a relatively long time A until the limit switch LS is lifted, the four-way switching valve 4 is switched, and the check valve 2 starts to open, and the check valve actually opens. The rise time B during high-speed switching from fully opening to reaching maximum speed for the first time is usually only 0.
Although it is about 0.02 seconds, the operation start time A is required to be several times longer than this, which hinders high-speed injection.

In an attempt to improve this drawback, it has been considered to shift the position of the limit switch a little forward, but it is extremely difficult to adjust the position and it is difficult to keep the operation start time A constant.

The present invention aims to eliminate these drawbacks by providing an on-off valve and a throttle valve independently, the on-off valve improving the start-up characteristics, the throttle valve improving the linearity of the handle opening and the flow rate, This makes it possible to quickly switch to high-speed injection and to easily and reliably adjust the flow rate, that is, set the high-speed injection speed.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

FIG. 3 illustrates one embodiment of the present invention. Reference numeral 6 denotes a valve body, one end of which is connected to a head end 7 of an injection cylinder, and the other end connected to an accumulator 8.

Inside the valve body 6, a check valve 9, which is an on-off valve, and a throttle valve 11 for flow rate adjustment, which can change its position and adjust the flow rate by turning a handle 10, are arranged in series. ing.

A part of the outer periphery of the check valve 9 is a stepped surface 9a, and the pressure of the accumulator 8 is applied to this surface 9a.
Open (acting in the direction.

On the other hand, the rear end side of the check valve 9 is connected to the A port of the four-way switching valve 13 via the check valve 12 facing the rear end side of the check valve 9, and the P port of the four-way switching valve 13 is connected to the accumulator. 8 is connected.

Therefore, when the accumulator pressure is acting on the rear end side of the check valve 9, which has an area larger than the area of the stepped surface 9a, the check valve 9 is closed.

14 is a compression spring. The flow path on the way to the check valve 12 branches and is connected to the tank 16 via a pilot check valve 15 facing toward the rear end of the check valve 9 .

The pilot port of the pilot check valve 15 is connected to the four-way switching valve 130B port.

Further, the T port of the four-way switching valve 13 is connected to the tank 16.

In order to obtain the rising characteristics, a four-way switching valve 13 with good responsiveness was used, and a pilot check valve 15 with a somewhat large flow rate was used.

At the portion where the outer circumference of the tip of the check valve 9 and the inner circumference of the valve body 6 come into contact, only a slight chamfer 9b is formed in order to improve the rising characteristics.

When the check valve 9 is opened, a large amount of oil immediately flows out.

Further, the throttle valve 11 for flow rate adjustment and the valve stem 10a, which is integrated with the handle 10, are rotatably integrated, and are opened toward the head end side of the injection cylinder 7 in advance according to the desired high-speed injection speed. I was able to put it away.

The tip portion 11a of the throttle valve 11 is designed to have a parabolic circumferential ridge line that improves the linearity of the handle opening and the flow rate.

By improving the linearity between the handle opening of the throttle valve 11 and the flow rate, that is, by making the handle opening and the flow rate through the throttle valve 11 proportional, the flow rate can be adjusted without relying on the operator's experience. This allows anyone to easily and reliably set high-speed injection speeds.

Next, the operation of this embodiment configured as above will be explained.

First, in the state shown in FIG. 3, the pressure of the accumulator 8 is guided to the front end and rear end of the check valve 9, which is an on-off valve. Since the check valve 9 is closed, the hydraulic oil from the accumulator 8 is not supplied to the injection cylinder side, and the hydraulic oil is supplied to the head side of the injection cylinder 7 from a hydraulic source (not shown). Slow injection is taking place.

When the piston rond (not shown) of the injection cylinder 70 moves forward and the limit switch LS is released, the four-way switching valve 13 is switched by the signal, the P port and the B port are connected, and the pilot chinic valve 15 is connected to the pilot valve 15. Pressure is applied and the pilot check valve 15 opens.

As a result, the rear end side of the check valve 9 is connected to the tank 16.

Since the accumulator pressure is acting on the check valve 90 surface 9a, the check valve 9 opens.

The tip of the check valve 9 is only provided with a slight chamfer 9b, and the check valve 9 opens almost instantaneously (
.

On the other hand, since the flow rate adjustment throttle valve 11 is opened in advance with a predetermined opening degree, the hydraulic oil from the accumulator 8 is immediately guided to the injection cylinder 7 side with a flow rate corresponding to the opening degree, and high-speed injection is achieved. It is done in an extremely short time.

Therefore, the rise characteristics of the injection cylinder during high-speed injection are significantly improved.

In the above embodiment, the throttle valve is placed next to the on-off valve, but the throttle valve may be placed before the on-off valve.

However, if the throttle valve is placed after the opening/closing valve, the bundle operation of the throttle valve can be performed when the pressure of the accumulator is not acting, so the bundle operation may be lighter.

As is clear from the above description, according to the present invention, the configuration is as set forth in the claims, the opening/closing valve consisting of a check valve and the throttle valve are separated, and the tip of the check valve is Since it is seated on the valve seat on the inner peripheral surface of the valve body through a slight chamfer, its opening and closing are instantaneous, improving the start-up performance of high-speed injection.

In addition, the throttle valve has a structure that allows its opening degree to be freely adjusted, and it is in a state where it is opened toward the injection cylinder 1 in advance, and the hydraulic oil for high-speed injection on the accumulator side is released at the moment when the on-off valve consisting of a check valve opens. The injection cylinder is immediately guided to the head side of the injection cylinder, achieving a high-speed injection state in an extremely short time, and the rise characteristics of high-speed injection can be greatly improved.

Furthermore, the throttling valve has a throttling line on the circumferential surface of the tip part formed on a parabola, and has a valve structure that achieves linearity between the bundle opening degree and the flow rate. Anyone can always set the injection speed reliably and easily, and stable injection conditions can be obtained reliably and easily.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a conventional device similar to the present invention, Fig. 2 is a diagram illustrating the relationship between injection speed and injection time, and Fig. 3 is a longitudinal cross-sectional view showing an embodiment of the present invention. It is a diagram. 1.6...Valve body, 2,9,12...Check valve, 3,10...Bundle, 4,13...
...Four-way switching valve, 7...Injection cylinder,
8... Accumulator, 11... Throttle valve, 15... Pilot check valve.

Claims (1)

[Claims] 1. In the connection passage from the accumulator to the head end side of the injection cylinder, there is an on-off valve with a valve structure having a chamfered part at the contact area between the outer circumference of the tip of the check valve and the inner circumference of the valve body, and the circumference of the tip. A crest valve for flow rate adjustment, which has a valve structure with a parabolic ridgeline, is installed in series, and a four-way switching valve for operating the on-off valve is installed between the accumulator and the rear end of the on-off valve. An injection device for a die-casting machine, characterized by being provided with.