JPH042836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a poppet-type three-port directional control valve having a built-in self-holding mechanism for self-holding the switching position of a valve body.

[Prior Art] In general, directional control valves are broadly classified into spool seal type and poppet seal type.Compared to spool seal type, poppet seal type has two types of directional control valves: a. Small stroke required.

b. Sealing is achieved by pressing the sealing surface against the valve seat due to the presser load, so the sealing is reliable.

c Since there are no sliding parts, there will be no malfunction due to sliding resistance, etc.

It has the following advantages and can provide superior stability.

However, the poppet seal type directional control valve described above performs sealing by applying a presser load generated by an electric signal (in the case of a solenoid valve) or a fluid pressure signal (in the case of a fluid pressure operated valve) to the valve body. Therefore, when the presser load is removed due to a power outage or malfunction, the sealing state is also released, causing the problem that equipment connected to it may move unnecessarily.

Therefore, as a directional control valve to solve this problem, a poppet-type five-port valve having a self-holding function as shown in FIG. 4 has been proposed.

The 5-port valve shown in FIG. 4 connects the pressure receiving chambers 2 and 3 on both sides of the main valve body 1 to the supply port 6 via solenoid valves 4 and 5, respectively, and connects the pressure receiving chambers 2 and 3 with these solenoid valves. The main valve body 1 is driven by alternately supplying and discharging pilot fluid, and this 5-port valve is always in the main valve body 1 at the switching position of the main valve body 1.
Since the supply fluid pressure from the supply port is acting on the main valve body, the main valve body can be self-retained by the difference in pressure receiving area of the main valve body, but the supply fluid pressure is acting on only one side of the main valve body. In the case of a three-port valve, there is a problem in that the main valve body cannot be self-retained by utilizing the difference in pressure receiving area.

[Problems to be Solved by the Invention] The present invention provides a self-supporting valve that can stably hold the main valve body by itself, regardless of the difference in pressure receiving area of the poppet-shaped main valve body or the magnitude of the supplied fluid pressure. The problem to be solved is to obtain a poppet type three-port directional control valve with a built-in holding mechanism.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the output port and the supply port are provided in the valve body of the main valve section, which is provided with a supply port, an output port, and a discharge port. and a poppet-shaped main valve body that switches the flow path between the ports, and the main valve body is driven by supplying and discharging pilot fluid to pilot portions arranged on both sides of the main valve body to switch the flow path between the ports. In the poppet type 3-port directional control valve, a rod having a pair of locking parts between the poppet type main valve element and the pilot part, the distance between which is slightly larger than the stroke of the main valve element; A self-holding mechanism is built in, which includes a locking member that locks into the locking portion of the valve and holds the position thereof, and an overtravel spring between the rod and the main valve body.

[Operation] When pilot fluid is supplied to one pilot section and the pilot fluid is discharged to the other pilot section, the rod on the pilot fluid supply side releases the locking section from the locking member, and the locking member is released. The poppet-shaped main valve body switches the communication between the ports, and the discharge side rod also slides to the position where it locks with the next locking part. Slide into the locking position. In this case, since the distance between the pair of locking parts is slightly larger than the stroke of the main valve body,
The overtravel spring of the self-holding mechanism on the pilot fluid supply side is compressed, and the overtravel spring of the self-holding mechanism on the pilot fluid discharge side expands, causing the locking member to lock to the next locking part. This state is maintained.

Therefore, the main valve body is pressed to the switching position by the difference in biasing force between the overtravel springs on the supply side and the discharge side, so it self-maintains the switching position even if the pilot fluid pressure decreases or is lost. ing.

When the supply and discharge of pilot fluid to and from the pilot section are reversed, the main valve body slides in the opposite direction to switch the communication between the ports, and as in the case described above, the difference in the biasing force of the overtravel spring causes the main valve body to slide in the opposite direction. The switching position is maintained by itself.

In this way, the main valve element self-holds its switching position due to the difference in the biasing force of the overtravel spring in the self-holding mechanism, so even if the difference in the pressure receiving area of the valve element is small or the supply fluid pressure is low, The holding function will not become unstable.

Further, it can be used as either a normally closed or always open directional control valve.

[Example] Figures 1 to 3 show examples of the present invention,
This poppet type 3-port directional control valve has a main valve section 1
1. It is equipped with self-holding mechanism parts 12a, 12b and pilot parts 13a, 13b.

The main valve section 11 includes a fluid supply port P, an output port A, a discharge port R, and valve seats 16a and 16 in an axial fluid flow path 15 that communicates these ports.
The valve body 17 and the valve seat 16 are provided facing each other.
A poppet-shaped main valve body 18 is provided which switches the flow path between the output port A, the supply port P, and the discharge port R by alternately opening and closing ports a and 16b.

The holding part bodies 20a and 20b in the self-holding mechanism parts 12a and 12b have a through hole penetrating in the extending direction of the flow path 15, and the main valve body 18 is inserted into this through hole.
Self-holding mechanisms 21a and 21b are provided for holding. The cylindrical detent bodies 22a, 22b in the self-holding mechanisms 21a, 21b are as follows:
Balls 23, . . . as an example of a locking member are inserted into a plurality of radial holes formed on the pilot portion side and spaced at equal intervals in the circumferential direction.
... is urged toward the center by the contractile force of a circular spring 24 fitted in a groove on the outer periphery of the detent body, and its tips are connected to the detent bodies 22a, 22b.
It protrudes from the hole toward the center, and its periphery is supported by the edge of the hole (see Figure 2). Therefore, the balls 23, . . . are urged toward the center by a single spring 24 with substantially uniform force.

The rods 25a, 25b, which are slidably inserted into the detent bodies 22a, 22b, have the balls 23, . A pair of locking parts 27a, 28a and 27b, 28b
(see Figures 2 and 3), and the distance between the locking parts 27a, 28a and 27b, 28b is slightly larger than the stroke of the main valve body 18 alternately opening and closing the valve seats 16a, 16b. It is formed. As shown in FIG. 2 and FIG.
Short cylindrical rings 29a and 29b whose diameters are reduced near the ends and which are loosely fitted to the tips of the reduced diameter portions are connected to the floating holes 30 and 29b.
30 and a spring pin 32 passing through a radial pin hole 31 formed at the other end of the rod prevents the rod from coming off, and an overtravel spring 33 is loosely fitted around the outer periphery of the reduced diameter portion of the rod.
a, 33b in the direction of the main valve body 18.

The rod, ring and overtravel springs integrated by the spring pin 32 are
The self-holding mechanisms 21a, 21b are sub-assembled by locking one of the locking portions with the balls 23, .

The self-holding mechanisms 20a and 20b are
If set within 0a, 20b, ball 2
3,... are locked in the locking parts 27a, 27b, the overtravel springs 33a, 33b
The spring pin 32 moves into the floating hole 3 against the urging force of
0 (see the upper half of Figure 3), and when it is locked in the locking parts 28a and 28b, the floating hole 30 is moved by the biasing force of the overtravel spring.
The biasing force of overtravel springs 33a and 33b is set so that they are located on the main valve side.

The pilot parts 13a, 13b have cylinders in pilot bodies 35a, 35b, and pilot pistons 36a, 36 that slide inside the cylinders.
Pilot chambers 37a, 37 divided by b
Pilot ports 38a and 38b are opened at b.

Next, the operation of the above embodiment will be explained with reference to FIG.

The upper half of FIG.
Pilot fluid is supplied to the pilot chamber 37a.
The figure shows a state in which the main valve body 18 closes the valve seat 16a and opens the valve seat 16b after the pilot fluid has been discharged. In this state, the self-holding mechanism 2
1b's balls 23,... are the locking portions 2 of the rod 25b
8b, the overtravel spring 33b is slightly compressed, while the balls 23,... of the self-holding mechanism 21a are
The overtravel spring 33a expands due to being locked to the locking portion 27a of a, and its biasing force does not act on the main valve body 18.
is pressed against the valve seat 16a by the biasing force of the overtravel spring 33b. Therefore, in the state shown in the upper half of FIG.
Even if the fluid pressure in the piping port 7b decreases or is lost, the main valve body 18 self-maintains the switching position in which the flow path between the ports A and R is communicated and the communication between the ports P and A is cut off.

When the supply and discharge of pilot fluid to and from the pilot chambers 37a and 37b is reversed, the pilot piston 36
a slides to the right in the figure while pressing the rod 25a etc., thereby locking portions 27a and 28
The convex part 26 between a expands the balls 23 against the biasing force of the annular spring 24, so that the balls 2
3, . . . are locked to the locking portion 28a, whereby the main valve body 18 is switched to a position where the valve seat 16a is opened and the valve seat 16b is closed. On the other hand, Rod 25b is
The convex portion 2 is moved by the pressing force of the pilot piston 36a and the urging force of the overtravel spring 33b.
6 expands the balls 23,..., and the balls 23,...
slides to the position where it locks on the locking part 27b (the first
(See bottom half of figure).

In this case, the locking parts 27a, 28a and 27b,
Since the distance between 28b and 28b is slightly larger than the stroke of the main valve element 18, the overtravel spring 33a is compressed and the 33b is expanded. is being pressed against. Therefore, even if the pilot fluid pressure in the pilot chamber 37a decreases or is lost, this switching position is self-maintained.

In this way, the main valve body 18 self-maintains the switching position by the biasing force of the overtravel spring 33a or 33b, so even when the difference in pressure receiving area is small or when the supply fluid pressure is low,
The self-holding function never becomes unstable.

[Effects of the Invention] The poppet type 3-port directional control valve of the present invention has the following advantages: The distance between the locking portions of the pair of locks provided on the rod is made slightly larger than the stroke of the main valve body.
Even in the case of a three-port valve in which supply fluid pressure acts only on one side of the main valve body, the main valve body can self-maintain the switching position by the overtravel spring.

Therefore, it can not only be used for either always open or always closed, but also has a reliable self-holding function even when the difference in the pressure receiving area of the main valve body is small or when the supply fluid pressure is low. It is.

Furthermore, since the self-holding mechanism is built in between the main valve section and the pilot section, there is no need to provide a separate self-holding mechanism.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view showing the operating state of the embodiment of the present invention, FIG. 2 is an enlarged sectional view of the self-holding mechanism,
Figure 3 is a cross-sectional view showing the relationship between the rod and the ring.
FIG. 4 is a schematic explanatory diagram of a conventional poppet type five-port directional control valve. 11... Main valve part, 13a, 13b... Pilot part, 17... Valve body, 18... Main valve body, 21
a, 21b... self-holding mechanism, 23... ball,
25a, 25b...rod, 27a, 27b, 2
8a, 28b...Locking portion, 33a, 33b...Overtravel spring, P...Supply port,
A...Output port, R...Exhaust port.

Claims (1)

[Scope of Claims] 1. A poppet-shaped main valve body for switching the flow path between the output port, the supply port, and the discharge port is provided in the valve body of the main valve portion equipped with a supply port, an output port, and a discharge port. , a poppet type 3-port directional control valve in which the main valve body is driven by supplying and discharging pilot fluid to pilot portions disposed on both sides of the valve body to switch the flow path between ports, the poppet type main valve body and A rod having a pair of locking portions with a distance between the rod and the pilot portion slightly larger than the stroke of the main valve body, and a locking member that locks on the pair of locking portions and maintains its position. and a poppet type 3-port directional control valve with a built-in self-holding part, characterized in that it has a built-in self-holding mechanism having an overtravel spring between the rod and the main valve body.