JPS5940129Y2 - Valve device for low speed injection of die casting machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve device for low-speed injection of a die-casting machine.

Generally, the injection cylinder of a die-casting machine operates at a low speed at the beginning of the injection operation, and in the middle of the injection, it becomes a high-speed injection state in a very short time.

In the injection device of a die-casting machine with such a configuration, when the injection cylinder initially moves from a stopped state in which it does not operate at all to a low-speed injection state, the pressure of the hydraulic oil suddenly increases.
Since the oil is added to the on-off valve, the on-off valve opens suddenly, and hydraulic oil is suddenly supplied to the chamber on the head side of the injection cylinder, resulting in problems such as the slow startup of the low-speed injection operation and the generation of shock.

Note that if a shock occurs at the start of low-speed injection, not only will it cause vibration and have a negative effect on the equipment, but the molten metal inside the injection sleeve will shake or vibrate, causing air to enter the molten metal. The temperature of the molten metal may drop slightly.

As a result, air may form a nest inside the injection product.
If the hot water flow becomes somewhat poor, it will be difficult to obtain high-quality injection products.

FIG. 1 shows a conventional on-off valve. This on-off valve 1 has a sliding valve body 3 separate from the screw shaft 2 in the direction of the distal end of the screw shaft 2. A compression spring 4 is elastically mounted between the valve body 3 and the wall surface of the valve device, and the force of the compression spring 4 constantly presses the valve body 3 against the valve seat 5.

The screw shaft 2 is led to the outside of the valve device, and by turning a handle 6 attached to this portion, the opening degree of the on-off valve 1 can be adjusted.

Hydraulic oil is led from a passage 7 on the side of a hydraulic pressure supply source consisting of a pump and a pressure accumulator facing the valve body 3, and is led through a passage 8 into a chamber on the head side of the injection cylinder (not shown).

Under such a structure, on the seat surface of the valve seat 5,
If a shape designed to ensure linearity between the opening degree of the handle 6 and the flow rate of oil flowing through the on-off valve, that is, the injection speed is adopted, a large amount of oil will flow out at once when the valve body 3 is opened. It is not possible to prevent the shock caused by this, and it is not possible to perform a shockless start.

The present invention was developed to eliminate the above-mentioned drawbacks of the conventional die-casting machine, and is designed to achieve linearity in handle opening and speed, as well as to enable shockless starting. The purpose is to provide a valve device for low-speed injection.

In order to achieve the above object, the present invention provides an on-off valve and a throttle valve in series in the middle of the flow path that supplies hydraulic oil to the chamber on the head side of the hydraulic cylinder, and the throttle valve adjusts the opening degree of the valve. It is configured to achieve linear speed and shockless start using an on-off valve.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 2 is a diagram for explaining one embodiment of the present invention. In the figure, what is generally designated by the reference numeral 10 is an on-off valve 13 and a throttle valve 15.
The flow path 11 formed on the side where the on-off valve 13 is installed at one end is connected to a hydraulic pressure supply source 25 consisting of a pump or a pressure accumulator, and the throttle valve at the other end The flow path 12 on the side where the injection cylinder 15 is provided is connected to the inside of the chamber 27 on the head side of the injection cylinder 26 .

In addition, in the injection cylinder 26, 28 is a piston, 2
9 is a chamber on the piston rond side.

A check valve type on-off valve 13 is arranged on the flow path 11 side.

This on-off valve 13 is constantly pressed in the direction of blocking the flow path 11 by a compression spring 14, and the on-off valve The ridge line on the outer peripheral surface of the tip of No. 13 has a gentle taper surface in the axial direction,
As shown in FIG. 2, when the on-off valve 13 is closed, its tip extends into the hydraulic oil passage 31 connecting the on-off valve 13 and the throttle valve 15, for example, by a dimension that is approximately the same as the diameter of the on-off valve 13. It is formed into a valve structure with a long protrusion.

On the other hand, a throttle valve 15 is arranged on the flow path 12 side facing the on-off valve 13 .

This throttle valve 15 is rotatably connected to the tip of a valve shaft 16 formed as a threaded shaft, and by turning a handle 17 fixed to the outer end of the valve shaft 16, the compression spring 18 is activated. It is configured so that the opening degree of the throttle valve 15 can be adjusted against the force.

The throttle valve 15 is set in advance to be opened at a predetermined valve opening degree in order to obtain the necessary flow rate when performing an injection operation.

The ridgeline of the circumferential surface of the valve tip of the throttle valve 15 is slightly swollen in a parabolic shape in order to provide linearity between the handle opening degree and the flow velocity.

On the other hand, a flow path 19 communicates between the flow path 11 on the side of the hydraulic pressure supply source 25 consisting of a pump or a pressure accumulator and the back surface of the on-off valve 13. A valve 20 and a variable throttle valve 21 are provided in series.

Further, a check valve 22 is provided toward the back of the on-off valve 13, bypassing the variable throttle valve 21.

The variable throttle valve 21 and the check valve 22 are configured as a pressure-temperature compensated valve 23, and the variable throttle valve 21 controls the opening speed of the on-off valve 13 to perform a shockless start of the injection cylinder.

In the switching valve 20, P, T, A, and B indicate respective ports, and the T port is communicated with the tank 24.

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

The pressure of hydraulic oil from a hydraulic pressure supply source 25 consisting of a pump and a pressure accumulator (not shown) is always applied to the flow path 11, but the switching valve 20 is in the state shown in FIG. When the port and the A port are in communication, the flow path 11
The same pressure is applied to the back of the on-off valve 13, and the pressure receiving area located in the flow path 11 on the tip side of the on-off valve 13 is smaller than the pressure receiving area on the back side.
is not opened, and hydraulic oil is not supplied into the chamber 27 on the head side of the injection cylinder 26.

On the other hand, when low-speed injection is performed, the switching valve 20 is switched, the P port side is blocked, the A port communicates with the T port, and therefore the hydraulic oil on the back side of the on-off valve 13 returns to the tank 24.

Therefore, the on-off valve 13 is opened by the pressure of the hydraulic oil applied to the tapered portion located in the flow path 11 on the tip side of the on-off valve 13, and the pump is pumped with a flow rate corresponding to the valve opening degree of the throttle valve 15 that has been opened in advance. Hydraulic oil from a hydraulic pressure supply source 25 consisting of a pressure accumulator is supplied into a chamber 27 on the head side of the injection cylinder 26, and low-speed injection is performed.

At this time, since the on-off valve 13 has a valve structure with a gently tapered surface to enable a shockless start, and because the tip of the on-off valve 13 protrudes long into the passage 31, this occurs. Since the flow resistance can be kept relatively large at all times, when the on-off valve 13 starts to open, the flow rate of the hydraulic oil increases little by little, and no shock occurs.

Furthermore, by appropriately setting the opening degree of the throttle valve 21, at the start of this low-speed injection, the throttle valve 21 controls the opening speed of the on-off valve 13, and thus the rising speed, to soften the shock.

In this way, the effect of the operation of the throttle valve 21 is further enhanced because the flow rate increases little by little by forming the tip of the on-off valve 13 into a gently tapered surface.

In addition, a shockless start can be reliably and easily obtained during low-speed injection.

Further, since the peripheral surface of the tip of the throttle valve 15 has a slightly parabolic bulge shape, when the valve opening is adjusted by the handle 17, linearity can be achieved in the relationship between the valve opening and the injection speed. I can do it.

Note that even if the piston 28 and piston rod 29 of the injection cylinder 26 are at the retraction limit and the rod-side chamber 30 of the injection cylinder 26 is connected to the tank, normally there is no air in the rod-side chamber 30 of the injection cylinder 26. , a little pressure remains, resulting in low resistance at the start.

However, during continuous operation, this pressure may change slightly over time, resulting in unstable starting conditions.

Therefore, in order to stabilize the value of this pressure remaining in the rod-side chamber 30 of the injection cylinder 26, for example, 5 k
It is also possible to apply a pressure of about g/c% and release it to the tank a few seconds before the start to help with a shockless start.

As is clear from the above explanation, according to the present invention, a gently tapered surface is provided in the middle of the flow path that connects the hydraulic pressure supply source and the chamber on the head side of the injection cylinder to enable a shockless start. An on-off valve with a valve structure in which the tip of the valve protrudes into the hydraulic oil passage for a long time and a throttle valve are connected in series, and the temperature and pressure supply source side of the on-off valve and the back side are connected by a flow path. However, the bottom of the tank is equipped with a switching valve and a variable throttle valve that control low-speed injection in the middle of this flow path, making it possible to reliably and easily achieve a shockless start during low-speed injection. It has a positive effect.

By being able to perform a shockless start at the start of low-speed injection, it is possible to eliminate shaking and vibration of the molten metal inside the injection sleeve, suppress air entrainment into the molten metal and decrease in molten metal temperature, etc. It becomes easier to obtain high-quality injection products with good circulation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional valve device, and FIG. 2 is a longitudinal sectional view showing one embodiment of the present invention. 1.13...Opening/closing valve, 3...Valve body, 6
, 17... Handle, 10... Valve device, 11, 12.19... Channel, 15...
... Throttle valve, 20... Switching valve, 21...
...Variable throttle valve, 22...Check valve, 25.
・・・・・・Hydraulic supply source, N・・・・Injection cylinder,
27... Head side chamber, 31... Passage.

Claims (1)

[Scope of utility model registration request] In the middle of the flow path connecting the hydraulic pressure supply source and the chamber on the head side of the injection cylinder, the ridge line on the outer peripheral surface of the tip has a gentle taper surface in the axial direction.When the valve is closed, the tip A check valve-type on-off valve with a valve structure that protrudes into the hydraulic oil passage for a long time to enable shockless start, and a flow path that connects the hydraulic power source side and the back of the on-off valve with a throttle valve in series. A die-cast Thomasin low-speed injection valve device characterized by having a switching valve for low-speed injection start and a variable throttle valve installed in series in the middle of the valve.