JPH0112044Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a spool-shaped on-off valve for high-speed injection of die-casting machines, for example, and more specifically, it can prevent shock when the spool moves at high speed when the valve opens. The present invention relates to an on-off valve configured as follows.

For example, when injecting molten metal into a mold in a die-casting machine, etc., a method is adopted in which the injection plunger is moved at low speed to perform low-speed injection in the initial stage, and then high-speed injection is performed in the middle.
Switching from low speed to high speed is performed by an on-off valve.

An example of such a conventional on-off valve device is shown in FIG.

The on-off valve, which is designated as a whole by reference numeral 1 in the figure, has a spool 2, which has a cylindrical shape with one end open and the other end shaped like a warhead. The valve seat 6 faces the inlet 4 and can be seated on a valve seat 6 formed at the inlet end of a hydraulic passage 5 to an injection cylinder (not shown) or the like. aisle 5
The tip of a flow rate control valve 7 that can be adjusted from the outside faces a valve seat 8 provided in the middle of the flow rate control valve 7, and the opening degree of the flow rate control valve 7 is normally adjusted as appropriate.

On the other hand, a spring 11 is loaded between the bottom surface of the center hole 9 of the spool 2 and the rear end of the valve cylinder 10, and constantly applies a pressing force to the spool 2 in the direction of closing the spool 2. There is. Also, valve cylinder 10
One relatively large-diameter hydraulic oil inlet/outlet 10a is formed in the rear end axis. Numeral 17 is a bolt for attaching the valve cylinder 10 to the manifold 18.

In the example shown in FIG. 1, the hydraulic pressure from the accumulator 3 is applied to the hydraulic oil inlet 4 side where the warhead-shaped tip of the spool 2 faces,
If the hydraulic pressure applied to the rear end side of the spool 2 is the same, the spool 2 will always have a larger pressure receiving area on the rear end side due to the difference between the pressure receiving area on the tip side and the pressure receiving area on the rear end side. The spool is pushed in the tightening direction, and the pressing force from the spring 11 is further applied to ensure that the spool is kept in the closed state as shown in FIG. 12 is an electromagnetic switching valve for high-speed injection provided between the accumulator 3 and the entrance/exit 10a, and 12a is a tank.

Based on such a structure, for example, in the case of a die-casting machine, at the initial stage of injection, hydraulic oil for low-speed injection is guided to the injection cylinder through a passage (not shown), and low-speed injection is performed.

When switching to high-speed injection, a control signal is input to the solenoid of the electromagnetic switching valve 12 provided between the accumulator 3 and the inlet/outlet 10a, the switching valve 12 is switched, and the inlet/outlet 10a is connected to the switching valve 12. It leads to the tank 12a through the tank 12a. As a result, the hydraulic pressure no longer acts on the rear side of the spool 2, and the high-pressure hydraulic oil from the accumulator 3 is applied only to the tip side of the spool 2, which releases the blockage of the spool 2 due to the difference in pressure-receiving area mentioned above, and spools the spool 2. 2 overcomes the elastic force of the spring 11 and moves to the left in the figure and opens, the inlet 4 becomes in communication with the passage 5, and the high-pressure hydraulic oil of the accumulator 3 flows from the passage 5 to the cylinder side, resulting in high-speed injection. It is done.

In such a hydraulic valve, the hydraulic fluid inlet/outlet 10a has a relatively large diameter, so there is no cushioning effect, and the spool 2 is suddenly pushed backwards within an extremely short time of about 0.02 seconds by the action of the hydraulic pressure of the accumulator 3. Therefore, at the time of switching, the rear end of the spool 2 violently collides with the seating surface 10b of the valve barrel 10, and this shock not only causes vibration, but also damages the rear end of the spool 2 and the seating surface. 10b may be partially worn, or the outer peripheral portion of the collision surface may bulge, causing galling, making it impossible to expect accurate operation of the spool 2, and possibly causing oil leakage.

The present invention eliminates the above-mentioned drawbacks of the conventional method, and prevents the spool from being shocked when switching.
The object of the present invention is to provide a hydraulic valve configured to ensure reliable operation of a spool.

In order to achieve the above object, the present invention employs a structure in which a large number of small-diameter hydraulic oil discharge holes are provided in the seating area where the rear end of the spool of the hydraulic valve contacts, thereby providing a hydraulic cushioning action.

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

Figure 2 illustrates an embodiment of the present invention.
In the figure, the same or corresponding parts as those in FIG.

A spool 2 is slidably provided in the inner hole of a sleeve 19 provided in the on-off valve 1, and a small diameter portion 2b having a smaller diameter than the outer peripheral sliding surface 2a is provided at the tip of the spool 2, and the outer periphery of the tip of the small diameter portion 2b is A tapered surface 2c that can be brought into contact with a valve seat 6 provided on a sleeve 19 is provided on the surface portion, and a spring 11 for closing the spool is provided on the rear side of the spool 2. The outer circumferential surface portion 2d of the spool 2 between the outer circumferential sliding surface 2a and the small diameter portion 2b of the spool 2 is directly connected to the accumulator 3, which is a high-pressure oil pressure source, via the inlet 4, and a chamber 20 on the rear end side of the spool 2
can be selectively communicated with the accumulator 3 and tank 12a via the switching valve 12, and when the valve is closed, high-pressure hydraulic oil is applied to the chamber 20 on the rear end side of the spool 2, and when the valve is commanded to open, the switching valve By switching 12, the hydraulic oil in the chamber 20 on the rear end side of the spool 2 is released to the tank 21a, so that the valve can be opened and closed.

In this embodiment, a ring-shaped plate 13 is provided on the seating surface 10b against which the rear surface of the spool 2 comes into contact when switching the spool 2.
A large number of small-diameter hydraulic oil discharge holes 14 are formed at equal intervals in the circumferential direction for generating a hydraulic cushion effect near the end of the valve opening.

For example, 24 of these hydraulic oil discharge holes 14 are formed at equal angular intervals in the circumferential direction, one end of which is opened in the seating surface portion 10b on the spool 2 side, and the other end is formed along the outer periphery of the plate 13. The passage 15 communicates with the switching valve 12 via an inlet/outlet 16 for hydraulic oil. Further, the hydraulic oil inlet/outlet 10a, which was conventionally formed at the rear end of the valve cylinder 10, is not provided.

In addition, since the plate 13 can be made integrally with the valve cylinder 10, the plate 13 can be considered as a part of the valve cylinder 10 in the present invention.

Next, the operation of the on-off valve according to the present invention constructed as above will be explained.

Spool 2 before the on-off valve is switched
Hydraulic pressure of the same pressure is guided to the tip and rear end of the spool 2 as in the conventional example described above, and the spool 2 moves to the right in the figure as shown in Fig. 2 due to the difference in the pressure receiving area. However, the space between the inlet 4 and the passage 5 is closed. In this state, the injection cylinder performs low-speed injection.

When switching to high-speed injection, the electromagnetic switching valve 12
Due to the action of the high-speed switching signal, the switching valve 12 is switched and the pressure on the rear side of the spool 2 is released. Therefore, due to the action of the high-pressure oil from the accumulator 3, the spool 2 is reversed in the force relationship due to the difference in pressure receiving area described above, is pushed backward, that is, to the left in FIG. are in communication, high pressure hydraulic oil from the accumulator 3 is guided to the injection cylinder, and high-speed injection is performed.

On the other hand, at this time, due to the retreat of the spool 2, the hydraulic oil between the plate 13 and the retreat of the spool 2 is discharged from the discharge hole 14 through the passage 15 to the discharge pipe 16.

When the spool 2 retreats, as the distance between the spool 2 and the seating surface portion 10b becomes smaller, the passage of the drained oil to the drain hole 14 becomes gradually narrower, and is finally completely closed. . A hydraulic cushion effect therefore occurs.

That is, in the present invention, since a large number of small-diameter hydraulic oil discharge holes 14 are provided in the seating surface portion 10b in the chamber 20, the cross-sectional area of the small-diameter hydraulic oil discharge holes 14 provided in large numbers, for example, 24, is The sum total of is large enough to allow sufficient discharge of hydraulic oil during the opening of the valve, and the hydraulic oil discharge hole is drained from the axial direction of the inlet of the hydraulic oil drain hole 14 and from a direction considerably inclined with respect to this axial direction. Since the flow path area and amount of the hydraulic oil pushed toward the inlet of the valve 14 and flowing out are very large, the spool 2 moves smoothly with almost no resistance, and a sufficient valve opening speed can be ensured. Then, as the spool 2 approaches the seating surface portion 10b, the flow path range and amount of hydraulic oil pushed toward the entrance of the hydraulic oil discharge hole 14 gradually decrease, and eventually,
Near the end of the valve opening when the spool 2 is very close to the seating surface 10b, it is directed toward the inlet of the large number of small-diameter hydraulic oil discharge holes 14, and in the axial direction of the inlet of the hydraulic oil discharge hole 14 and The flow path range and amount of hydraulic oil pushed in from a considerably inclined direction are extremely small. In this case,
The amount of hydraulic oil located along the seating surface portion 10b that enters the hydraulic oil discharge hole 14 from the side of the hydraulic oil discharge hole 14 is limited, and from the radial direction, the amount of hydraulic oil that enters the hydraulic oil discharge hole 14 is limited.
It can hardly flow into 4. As a result, when the spool 2 approaches the seating surface portion 10b, the hydraulic cushioning action is activated, the brake is applied, and the spool 2 does not collide with the seating surface portion 10b.

Note that if only one large-diameter hydraulic oil discharge hole is provided in the seating surface 10b, the spool 2
0b, the flow path range and amount of hydraulic oil pushed in from the axial direction of the inlet of the hydraulic oil discharge hole and from a direction considerably inclined to this axial direction are quite large, so as in the present invention, It is not possible to obtain a proper cushioning effect.

In this way, the spool 2 does not collide with the seating surface portion 10b unlike in the conventional structure described above, and no shock occurs. As a result, there is no distortion due to impact on any part of the on-off valve, there is no wear or swelling of the outer periphery due to a collision between the rear surface of the spool and the seating surface, there is no oil leakage, and accurate switching operation is possible. becomes.

As is clear from the above explanation, according to the present invention, when the spool is moved to open the on-off valve during switching, a structure is adopted in which a large number of small-diameter hydraulic oil discharge holes are formed in the seating surface of the spool. For,
When the spool moves, the passage of oil pushed into the discharge hole gradually becomes narrower, and as a result, a brake is applied by the hydraulic cushion action, preventing the spool from colliding with the seating surface, and the shock is significantly softened.
There is no wear on the seating surface or misalignment of the components, ensuring reliable operation.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a conventional device similar to the present invention, and FIG. 2 is a vertical cross-sectional view showing an embodiment of the present invention. 1... Opening/closing valve, 2... Spool, 3... Accumulator, 4... Inlet, 5... Passage, 6, 8...
Valve seat, 7...Flow control valve, 10...Valve cylinder, 10
a, 16... Entrance/exit, 10b... Seating surface section, 11
... Spring, 12 ... Solenoid switching valve, 13 ...
Plate, 14... discharge hole.

Claims (1)

[Scope of utility model registration request] A spool is slidably provided in the inner hole of the valve device,
A small diameter part smaller than the outer peripheral sliding surface is provided at the tip of the spool, a tapered surface is provided on the outer peripheral surface of the tip of the small diameter part so that it can come into contact with the valve seat provided in the inner hole, and the spool is attached to the rear side of the spool. A closing spring is provided,
The outer peripheral surface of the spool between the outer peripheral sliding surface and the small diameter part of the spool is directly connected to a high-pressure hydraulic power source, and the chamber on the rear end side of the spool is selectively communicated with the high-pressure hydraulic power source and a tank via a switching valve. When the valve is closed, high-pressure hydraulic oil is applied to the chamber at the rear end of the spool, and when the valve is commanded to open, the hydraulic oil in the chamber at the rear end of the spool is released to the tank by switching the switching valve. In on-off valves that open and close the valve, the seat surface inside the chamber at the rear end, where the back of the spool comes into contact when the spool opens, has many small-diameter hydraulic oil discharge holes to generate a hydraulic cushioning effect near the end of the valve opening. Separate on-off valves.