JPS5927972Y2 - 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 invention relates to an injection device for a die-casting machine that can switch to high-speed injection, that is, quickly start up when switching to high-speed. It is related to.

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

Figure 1 shows a conventional device, where 1 is the valve body, 2 is a check valve that doubles as an opening/closing valve and a throttle valve for adjusting flow rate, 3 is a handle for adjusting the opening degree, 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 outleft is connected to the head side of the injection cylinder.

In the illustrated state, the handle 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 operating the handle 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 outleft side.

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 an on-off valve and a throttle valve, the throttle part at the tip of check valve 2 is made longer in order to maintain linearity between the handle 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 rod of the injection cylinder. It was emitted by contact with the limit switch LS installed at the position.

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

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, the time A from when the limit switch LS is turned on and the four-way switching valve 4 is switched until the check valve 2 begins to open is relatively long, and in reality, the time A from which the check valve 2 begins to open is relatively long. The rise time B during high speed switching from fully opening to reaching maximum speed is usually only 0.
Although it was about 0.02 seconds, the operation start time A was required to be several times longer than this, which hindered 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 was developed in order to eliminate these drawbacks.The on-off valve and the throttle valve are provided independently, and instead of using a large-flow four-way switching valve, a small one that switches quickly is used. , it is possible to quickly switch to high-speed injection.

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, in which 6 is a valve body connected at one end to the head end 7 of the injection cylinder;
The other end is connected to the accumulator 8.

Inside the valve body 6 is a first check valve 9 that functions as an on-off valve.
A throttle valve 11 for flow rate adjustment, which can adjust the flow rate by changing the position of the handle 10 by turning the handle 10, is arranged in series.

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.
It acts in the direction of opening.

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 a second check valve 12 facing the rear end side of the check valve 9.
The port is connected to accumulator 8.

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 first check valve 9 .

The pilot port of the pilot check valve 15 is connected to the B port of the four-way switching valve 13.

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.

It should be noted that the tip of the first check valve 9 has only a slight chamfered portion 9b formed in the portion that contacts the inner circumferential surface of the valve body 6 in order to improve the rising characteristics.

In addition, the throttle valve 11 for flow rate adjustment, the handle 10, and the integrated valve stem 10a are rotatably integrated.
The head end side of the injection cylinder 7 can be opened in advance according to a desired high-speed injection speed.

The end surface 11a of the throttle valve 11 is designed to improve the linearity of the handle opening and the flow rate.

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 and rear ends of the first check valve 9, but the pressure of the accumulator 8 is guided to the rear end of the first check valve 9. Since the pressure receiving area is large, the first check valve 9 is closed, and the hydraulic oil from the accumulator 8 is not supplied to the injection cylinder side, and the head side of the injection cylinder 7 is operated from a hydraulic source (not shown). Oil is supplied and low-speed injection is performed.

Eventually, the piston rod (not shown) of the injection cylinder 7 moves forward and the limit switch LS is turned on, and the four-way switching valve 13 is switched by the signal, the P port and the B port are communicated, and pilot pressure is applied to the pilot check valve 15. As a result, 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 surface 9a of the check valve 9, the check valve 9 opens.

Only a slight chamfer 9b is provided at the tip of the check valve 9, and the first 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.

As is clear from the above description, according to the present invention, the structure is as described in the claims of the utility model registration, the first check valve and the throttle valve are separated, and the first check valve is Since the tip is seated on the valve seat on the inner circumferential surface of the valve body through a slight chamfer, its closing is instantaneous, improving the startup characteristics of high-speed injection.

In addition, the throttle valve has a structure that allows its opening degree to be freely adjusted, and it is opened toward the injection cylinder side in advance, and the hydraulic fluid for high-speed injection on the accumulator side is released at the moment the first check valve opens. It is immediately guided to the head side of the injection cylinder and enters a high-speed injection state in an extremely short time, making it possible to significantly improve the rise characteristics of high-speed injection.

[Brief explanation of drawings]

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...Handle, 4,13
...Four-way switching valve, 7... Injection cylinder, 8... Accumulator, 11... Throttle valve, 15... Pilot check valve.

Claims (1)

[Scope of utility model registration request] In the communication passage from the accumulator to the head end side of the injection cylinder, there is a first check valve that has a surface on its outer periphery on which the accumulator pressure acts in the direction of opening the main body and acts as an on-off valve, and a first check valve that acts as an on-off valve. A throttle valve is provided in series, the inlet passage of the first check valve is connected to the rear end side by a flow passage, and a four-way switching valve is connected to the A port of the four-way switching valve in the middle of this flow passage. A second check valve facing the rear end side of the first check valve is arranged in series, and the first check valve is arranged in a flow path connecting between the rear end side of the first check valve and the tank. An injection device for a die casting machine, in which a pilot check valve facing the rear end of the valve is arranged, and a pilot port of the pilot check valve is communicated with a B port of the four-way switching valve.