JPS6120357Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a poppet type switching valve.

A poppet-type switching valve with an internal pilot type as shown in FIG. 1 is conventionally known. This switching valve includes a valve body 1, an import 2, an out port 3, an exhaust port 4, a first valve port 5 that communicates the import 2 and the out port 3, and a first valve port 5 that communicates the out port 3 and the exhaust port 4. 2
A valve port 6 is provided, and a poppet valve body 7 and a piston 8 are fitted. The poppet valve body 7 and the piston 8 are fixedly connected by a valve stem 9 and slide up and down together, and are biased upward by return springs 10 and 11, respectively, so that the poppet valve body 7 When the first valve port 5 is closed, the piston 8 moves to the second
When the poppet valve body 7 opens the first valve port 5, the piston 8 closes the second valve port 6, and the opening/closing operation is performed using a valve installed outside the valve body 1. This is done by turning the electromagnetic pilot valve 12 on and off. That is, when the electromagnetic pilot valve 12 is off, the pilot pressure from the pilot pressure passage 13 does not act on the piston 8.
This piston 8 is opened and the poppet valve body 7 is closed. When the electromagnetic pilot valve 12 is turned on, pilot pressure acts on the piston 8, so the piston 8 is closed and the poppet valve body 7 is opened.

However, in this conventional switching valve, pilot pressure acts on the piston 8, causing the piston 8 to descend, and at the same time, the poppet valve body 7 also descends, causing the piston 8 to descend.
poppet valve body 7 before closing the second valve port 6
opens the first valve port 5, so the import 2 communicates with the out port 3 and the exhaust port 4,
This is what is called an underlap. Therefore, if the supply pressure is low or the piping on the import 2 side is thinner than the piping on the out port 3 side, the pilot pressure in the pilot pressure passage 13 will drop and the pressure acting on the piston 8 will decrease, causing the piston 8 And the poppet valve body 7 cannot be operated sufficiently, causing malfunction.
Furthermore, even if switching was possible, the operation was slow and there was a drawback that there was a lot of air loss from the exhaust port 4.

The present invention eliminates these drawbacks, and its characteristics are that the piston is provided with a convex portion and a guide hole that protrudes into the second valve port, and the tip of the valve stem is slidably inserted into this guide hole. In addition, a protrusion is provided in the middle of the valve stem that collides with the protrusion when the piston is actuated by the pilot pressure, and when the piston is actuated by the pilot pressure, the protrusion is brought into contact with the second valve opening. After the valve is closed, the poppet valve element opens the first valve port.

An embodiment of the present invention shown in FIGS. 2 and 3 will be described below. Note that the same components as those of the conventional one shown in FIG. 1 are given the same reference numerals.

The piston 8 is provided with a guide hole 14, into which the tip (upper end) of the valve rod 9 is slidably fitted, so that the piston 8 and the valve rod 9, and therefore the piston 8 and the poppet valve body, are fitted. It can be slid up and down separately from 7.

A convex portion 15 having a smaller diameter than the second valve port 6 is formed at the center of the lower surface of the piston 8, and a protrusion (flange) 16 is provided in the middle of the valve stem 9.

When the electromagnetic pilot valve 12 is turned on and pilot pressure acts on the piston 8 in the state shown in FIG. Since it is slidable, the poppet valve body 7 is not immediately pushed downward. When the piston 8 further descends, its convex portion 15 projects into the second valve port 6 and narrows the space between the out port 3 and the exhaust port 4. After that, as shown in FIG.
collides with the protrusion 16 and the valve stem 9 is pushed downward,
The poppet valve body 7 opens the first valve port 5, and the import 2 and the exhaust port 4 temporarily communicate with each other. However, at this time, since the space between the out port 3 and the exhaust port 4 is already narrowed by the convex portion 15, the drop in pilot pressure is small, and the air loss from the exhaust port 4 is also small.

As described above, in the switching valve of the present invention, the piston is actuated by the pilot pressure and its convex portion squeezes the second valve port, and then the poppet valve body opens the first valve port, so that the piston is actuated by the pilot pressure. This allows for accurate and quick switching between opening and closing, and less air loss.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional example, and FIGS. 2 and 3 are sectional views of an embodiment of the present invention. FIG. 2 shows a normal state, and FIG. 3 shows an operating state. 1... Valve body, 2... Import, 3... Out port, 4... Exhaust port, 5... First valve port, 6... Second valve port, 7... Poppet valve body, 8... ...Piston, 9...Valve stem, 10, 11...
...Return spring, 14...Guide hole, 15...Protrusion, 1
6... Protrusion.

Claims (1)

[Scope of utility model registration request] The valve body is provided with an import port, an out port, an exhaust port, a first valve port that communicates with the import port and the out port, and a second valve port that communicates with the out port and the exhaust port,
A poppet valve body and a piston connected to it by a valve stem are fitted, and when the poppet valve body closes the first valve port by the action of a return spring, the piston opens the second valve port. , in a poppet type switching valve in which the poppet valve element opens the first valve port when the piston closes the second valve port due to pilot pressure, the piston plunges into the second valve port; A convex portion and a guide hole are provided, and the tip of the valve stem is slidably fitted into this guide hole, and a convex portion and a guide hole are provided in the middle of the valve stem so that when the piston is actuated by pilot pressure, the convex portion and the guide hole collide with each other. A poppet-type switching valve characterized by having a contacting projection.