JPS6217813A - Three-port type pressure reducing valve - Google Patents

Abstract

PURPOSE:To improve the stability of a spool by connecting the other end side of a main spool to a secondary port and controlling the pressure of a spring room so as to be set up to a prescribed set pressure by a pilot relief valve. CONSTITUTION:A three port-type pressure reducing valve is provided with a main valve 11 consisting of the 1st and 2nd control parts 31, 32 and a pilot room 18 or the like arranged on one end side of the main spool 13. The spring room 25 is formed by compressing a spring 23 on the other end side of the main spool, the secondary port B is connected to the spring room 25 through a passage 27 having a diaphragm 26 and a pilot relief valve 22 is connected to the spring room. Consequently, the pressure of the spring room 25 of the main spool 13 is controlled so as to be set up to a prescribed set pressure by the valve 22. Thereby, the main spool 13 is driven so that the differential pressure between the pilot room 18 and the spring room 25 corresponds to the spring pressure of the spring 23 to reduce the pressure of the secondary port B from the pressure of the primary port A to the prescribed pressure. Consequently, the diameter of the main spool 13 can be increased and a large flow rate can be controlled.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a three-port pressure reducing valve.

<Prior art> Conventionally, there is a three-port pressure reducing valve of this type as shown in Fig. 2 (Japanese Patent Application Laid-open No. 51111525).
. This 3-port pressure reducing valve has a spool 2 slidably fitted into a valve chamber 9 formed in a main body 1,
The pressure of the secondary port B is guided to the pilot chamber 3 formed at one end side through the passage 4, while the other end of the spool 2 is pressed by the electromagnetic proportional solenoid 5, so that the pressure PR of the secondary port B The pressure in the pilot chamber 3 and the pushing force of the electromagnetic proportional solenoid 5 are made to oppose each other, and the spool 2 is operated to control the pressure PB at the secondary port B. The flow from the primary port A to the secondary port B is controlled by a first port formed at the corner of one end surface of the land 2a of the spool 2.
In the pressure control section 6a, a widening flow is formed in a trumpet shape from the ring center of the spool 2, and a flow from the pilot chamber 3 leading to the secondary port B to the tank port T is controlled by a flow formed on one end surface of the land 2b of the spool 2. 2 pressure system
By configuring the control 6b to form a widening flow that spreads in a trumpet shape, the so-called pinched flow that makes the spool 2 unstable is eliminated, and the flow from the primary port to the secondary port B and from the pilot chamber 3 to the tank The spool 2 is stabilized against the flow to the port T, and vibration and noise are prevented from occurring.

<Problems to be Solved by the Invention> However, in the conventional three-port pressure reducing valve described above, the pressure PB at the secondary port B led to the pilot chamber 3
Since the pressing force of the electromagnetic proportional solenoid 5, which has a restriction on the magnitude of the force, is directly opposed, there is a problem that the pressure PR at the secondary port B cannot be controlled to a high pressure. In other words, the electromagnetic proportional solenoid 5 increases the pressure PB at the secondary port B.
When controlling the electromagnetic proportional solenoid 5 to a high pressure, it is practically impossible to output the necessary pressing force due to the size and weight of the electromagnetic proportional solenoid 5. Furthermore, if the diameter of the spool 2 is increased in an attempt to control a large flow rate, the fluid force applied to one end of the spool 2 on the pilot chamber 3 side also increases, and the pressing force of the electromagnetic proportional solenoid 5 opposes this fluid force. I can't. That is, the conventional three-port pressure reducing valve described above has a problem in that it cannot control a large flow rate.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make it possible to set the secondary pressure at a high pressure and control a large flow rate while maintaining the stability of the spool due to the spreading flow.

<Means for Solving the Problems> In order to solve the above problems, the three-port pressure reducing valve of the present invention has the following features: One land 13 of the main spool 13
The flow spreads in the first pressure control section 31 formed at the corner of one end surface of b, while the flow from the pilot chamber 18, which is connected to the secondary port B and formed at one end of the main spool 13, to the tank port T. The flow is transferred to the main spool 13 above.
This is a three-port pressure reducing valve equipped with a main valve ml configured to spread out and form a flow in a second pressure control section 32 formed at the corner of one end surface of another land 13a, the other end of the main spool 31 being Spring chamber 2 with spring 23 mounted on the side
5, the secondary port B and the spring chamber 25 are communicated through a passage 27 having a throttle 26, and a pilot relief valve 22 is connected to the spring chamber 25.

<Function> With the above configuration, the spring chamber 25 on the other end side of the main spool 13
communicates with the secondary port B via a passage 27 having a throttle 26, and the pressure in the spring chamber 25 is controlled by a pilot relief valve 22 to a set pressure constant for firewood. Therefore, the main spool 13 of the main valve 11 is connected to the pilot chamber I8.
and the spring chamber 25 corresponds to the spring force of the spring 23, and the pressure at the secondary port B is changed to
The pressure is controlled to be reduced from the proof stress to a predetermined pressure. In this way, 2
Pressure in pilot chamber 18 leading to next port B and spring chamber 2
5 to operate the main spool 13,
By regulating the flow from the primary port A to the secondary port B and the flow from the pilot chamber 18 to the tank port T, the pressure at the secondary port B is controlled to be reduced, so a small operating force of the pilot relief valve 22 can reduce the pressure. As a result, the secondary pressure of the secondary port B can be set to a high pressure, and the main spool 13
By making the diameter large, large flow rates can be controlled. In addition, since the flow in the first pressure control section 31 and second pressure control section 32 of the main valve 11 is configured to spread and flow, the operation of the main spool 13 is stable, and vibration and noise generation is prevented. be done.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In FIG. 1, 11 is a three-port main valve, and 22 is a pilot relief valve.

The main valve 11 has a main spool 13 having three lands 13a, 13b, and 13c in a valve chamber 12 formed in the main body 10.
are slidably fitted. In the valve chamber 12, annular grooves 15, 16.
17 is provided, and this annular groove +5.16.17 is connected to tank 1.
9, the tank port T, the secondary port B, and the primary port A are connected to each other. A secondary port B is communicated with the pilot chamber 18 at one end of the main spool 13 via a passage 24 having a throttle 2I, while the main spool 1
A spring chamber 25 in which the spring 23 at the other end of 3 is compressed has an aperture 2.
The secondary port B is communicated via a passage 27 having a diameter of 6. Therefore, the main spool 13 operates based on the balance between the fluid pressure in the pilot chamber 18 and the fluid pressure in the spring chamber 25, and the differential pressure between the fluid pressure in the pilot chamber 18 and the fluid pressure in the spring chamber 25 is , the opening degree of the first pressure control section 31 formed at the course of the right end surface of the land 13b, and the second pressure control section formed at the corner of the left end surface of the land 13a so as to correspond to the spring force of the spring 23. The opening degree of the portion 32 and the opening degree of the third pressure control portion 33 formed at the corner of the left end surface of the land 13b are controlled. Above 1
Since the diameter of the annular groove 16 is larger than the diameter of the valve chamber 12 in the first pressure control section 31, the flow from the secondary port A to the secondary port B is a spreading flow that spreads out from the axis of the main spool 13 in a trumpet shape. becomes. Further, the flow from the pilot chamber 18 to the tank port T becomes a spreading flow because the diameter of the annular groove 15 is larger than the diameter of the pilot chamber 18 in the second pressure control section 32. Therefore, main spool 1
3 operates stably and does not generate vibration or noise.

As shown in FIG. 1, the land 13 of the main spool I3
The distance between the left end surface of a and the left end surface of the annular groove 15 is Lt, and the distance between the left end surface of the land 13b and the left end surface of the annular groove 16 is L3.
．． If the distance between the right end surface of land +3b and the right end surface of annular groove 16 is Ll, I-s>Lt, L3>L
l, L+≧L.

We have many relationships. In other words, when the relationship between L and L is L>Lt, the third pressure control section 33 from the secondary port B to the tank port T is the second pressure control section from the pilot chamber 18 to the tank port T. 32=7- is open and the first port from primary port A to secondary port B
It opens only after the pressure control section 31 closes, and L
In the case of l<Lx, the third pressure control section 33 opens only when the second pressure control section 32 opens after the first pressure control section 31 closes. Also, in the case of L + −L t,
The third pressure control section 33 opens only when the first pressure control section 31 closes and the second pressure control section 32 opens at the same time.

A pilot relief valve 22 is interposed in a passage that communicates the spring chamber 25 of the main valve 11 with the tank 40. The pilot relief valve 22 has a poppet 42 mounted on the valve seat 41.
The pressure is controlled by pressing with an adjustment handle 43 via a pressure adjustment spring 45.

A hydraulic cylinder 55 is connected to the secondary port B of the main valve 11 through a passage 56, and a pressure source 57 is connected to the primary port A of the main valve 11 through a passage 58.

In the above configuration, the control pressure of the pilot chamber leaf valve 22 is set to a constant pressure by operating the adjustment handle 43 of the pilot relief valve 22, and the pressure of the spring chamber 25 of the main valve 11 is controlled to a constant pressure. .

Then, the main spool 13 of the main valve 11 operates so that the differential pressure between the fluid pressure in the pilot chamber 18 and the fluid pressure in the spring chamber 25 becomes a value corresponding to the spring force of the spring 23. The opening degrees of the pressure control section 31 and the second pressure control section 32 are controlled to control the pressure of the secondary port B to a predetermined pressure. Moreover, when it is desired to lower the pressure of the secondary port B during control, the second pressure control section 32 is opened by lowering the set value of the pilot relief valve 22, so that the pressure of the secondary port B is lowered by lowering the set value of the pilot relief valve 22. The pressure drops instantly in response to the set pressure. At this time, the fluid flowing through the first pressure control section 31 from the primary port A to the secondary port B expands and becomes a flow, and the fluid flowing through the second pressure control section 32 from the pilot chamber 18 toward the tank port T. becomes a spreading flow. Therefore, the pressure control operation of the main spool 13 is stable, and generation of vibration and noise is prevented. In addition,
The throttle 21 provided in the passage 24 leading to the pilot chamber 18 is a damper throttle, which effectively performs a damping action to make the operation of the main valve 11 more stable.

Further, the pressure in the spring chamber 25 of the main valve 11 is controlled by the pilot relief valve 22, and the pilot chamber 18 of the main valve If is controlled.
The main spool 13 is actuated by making the fluid pressure inside the spring chamber 25 counter to the fluid pressure inside the spring chamber 25 to reduce the pressure at the secondary port B. A small push can be applied with force to the main valve 11, 2.
The pressure at the next port B can be controlled to a high pressure, and the main spool 13 can be made large in diameter to control a large flow rate.

Note that the third pressure control section 33 of the main valve 11 is connected to the secondary port B.
When the pressure becomes excessive and the second pressure control section 32 is fully opened, the secondary port B opens when the pressure becomes excessive.

<Effects of the Invention> As is clear from the above, according to the present invention, it is possible to set the secondary pressure at a high pressure while maintaining the stability of the pressure control operation of the main spool of the main valve due to the spreading flow, and it is possible to set the secondary pressure to a high pressure. Control becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a three-port pressure reducing valve according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional three-port pressure reducing valve. 11... Main valve, I3... Main spool, 18... Pilot chamber, 22... Pilot relief valve, 23...
...Spring, 25...Spring chamber.

Claims (1)

[Claims] (1) The flow from the primary port (A) to the secondary port (B) spreads at the first pressure control section (31) formed at the corner of one end surface of one land (13b) of the main spool (13). On the other hand, the flow from the pilot chamber (18), which is connected to the secondary port (B) and formed at one end of the main spool (13), to the tank port (T) is connected to the main spool (13). 3, which is provided with a main valve (11) configured to spread out and cause a flow in a second pressure control part (32) formed at the corner of one end surface of another land (13a).
It is a port type pressure reducing valve, and a spring chamber (25) in which a spring (23) is compressed is formed on the other end side of the main spool (31), and the secondary port (B) and the spring chamber (25) and a passageway (27) having a throttle (26), and a pilot relief valve (22) is further connected to the spring chamber (25).
Port type pressure reducing valve.