JPS59214923A - Pilot type pressure-reducing valve - Google Patents

Abstract

PURPOSE:To shorten the pressure setting time by connecting a flow rate controlling valve provided with pressure compensation and a check valve to a vent room and using a pressure setting pilot valve as a balance piston type relief valve. CONSTITUTION:In the titled pressure-reducing valve RV, an inlet port 2 and the vent room 7 in the body 1 are connected to each other through the pressure compensating flow rate control valve 11, an outlet port 3 is connected to the vent room 7 through the check valve 12 and the balance piston type relief valve 13 is built in the body 1 as the pressure setting pilot valve. The control valve 11 supplies always a constant flow rate to the vent room 7 so that the increase of the pressure P2 of the input port 2 moves a piston 11a to the left and narrows a flow course. When a peak pressure is generated from the outlet port 3, the check valve 12 makes the compressed oil flow to the arrow Y direction. The relief valve 13 discharges the residual oil in the vent room 7 to keep the pressure of the vent room 7 constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure control valve that is used in a fluid pressure circuit such as hydraulic pressure and adjusts the outlet side pressure to a set pressure lower than the inlet side pressure regardless of the inlet side pressure. Regarding the pilot type pressure reducing valve.

As shown in FIG. 1, the conventional pilot type pressure reducing valve opens and closes a main flow path that communicates an inlet boat 2 and an outlet boat 3 formed in a body 1, and connects the outlet boat 3 to an orifice 5. a main piston 4 having a flow path 6 communicating with the pen 1 to the chamber 7 via the main spring 8 which is housed in the vent chamber 7 and biases the main piston 4 in the direction of opening the main flow path; A poppet valve 10 is inserted between the drain boat 9 and the drain boat 9 and serves as a pilot valve for setting pressure.

In this pressure reducing valve RV, when the pressure P2 of the outlet port 3 reaches the set pressure of the poppet valve 10, the pilot oil q flows through the orifice 5 of the main piston 4 as shown by the arrow.
A difference occurs in the pressure applied to the upper and lower surfaces of the main piston 4.

That is, the effective area of the upper and lower surfaces of the main piston 4 is A,
Assuming that the pressure in the vent chamber 7 is P3, a force of AX (P2 P3) acts upward on the main piston 4. When the force becomes larger than the force F1 of the main spring 8, the main piston 4 moves upward and blocks the main flow path B, thereby controlling the pressure P2 of the exit robot B to be constant so as not to exceed the set pressure. do.

FIG. 2 shows an example of a hydraulic circuit when such a pilot type pressure reducing valve RV is used to drive the cylinder C via the switching valve S■.

However, in the conventional pilot type pressure reducing valve shown in FIG. 1, the pressure oil on the outlet port 3 side passes through the orifice 5 of the main piston 4 to escape from the poppet valve 10, Since the only force that lowers the pressure downward is the force F1 of the main spring 8, when the pressure reducing valve RV is actually used as shown in Fig. 2, when the outlet side of the pressure reducing valve RV opens from the blocked state due to the switching valve Sv,
As shown in FIG. 3, when the outlet pressure P2 suddenly drops and the outlet side is blocked from the open state, a peak pressure is generated as shown in FIG. 3, and it takes a long time for the pressure to settle until it returns to the set pressure.

That is, when the outlet side of the pressure reducing valve RV opens from the blocked state, the difference between the pressures P1 and P2 becomes large, so as shown by the arrow in FIG. Pressure oil flows at high speed to P
decreases from l.

On the other hand, since the pressure P1 is directly applied to the lower surface side of the flange portion 4b, an upward fluid force F2 acts on the main piston 4. Therefore, the force Fl exerted by the main spring 8 to push down the main piston 4 is weakened.

In addition, in order to lower the main piston 4, the vent chamber 7
However, since the differential pressure across the orifice 5 is small, the flow rate passing through the orifice 5 is small.

Therefore, the descending speed of the main piston 4 is slow, and it takes time for the pressure P2 of the exit robot B to rise to the set pressure.

When the outlet side of the pressure reducing valve RV is blocked from being open, the oil compressed in the outlet boat 3 must be quickly released, but the orifice 5 is small and the flow rate of the pylon l-valve 10 is also small. Moreover, the peak pressure was higher and the pressure settling time was longer.

Purpose This invention was made by focusing on the above-mentioned problems in the conventional pilot type pressure reducing valve. suppresses the generation of pressure,
The purpose is also to shorten the pressure settling time.

Therefore, the pilot type pressure reducing valve according to the present invention connects a flow control valve with pressure compensation that always supplies a constant flow rate from the inlet boat to the vent chamber, and maintains a cranking pressure higher than the cranking pressure of the main piston from the outlet port. A check valve with a diameter is connected to the vent chamber, and the pilot valve for pressure setting is a balanced piston type relief valve.

An embodiment of the present invention will be described below with reference to FIG. 4. Parts corresponding to those of the conventional example shown in FIG. 1 are denoted by the same reference numerals, and their explanation will be omitted.

The pressure reducing valve RV according to this embodiment connects an inlet boat 2 and a vent chamber 7 in a body 1 via a pressure compensated flow control valve 11, and connects an outlet port 3 and a vent chamber 7 to an outlet port 3.
It is connected via a check valve 12 that allows flow only in the direction of the vent chamber 7, and also has a built-in balance piston type relief valve 13 as a pilot valve for pressure setting.

The pressure compensated flow rate control valve 11 is a known one, and includes a piston 11a, a spring 11b that biases the piston 11a in the direction of opening the flow path, and a throttle 11c (the figure is a schematic illustration), an inlet boat. The pressure P2 of 2 is guided to the right end chamber of the piston 11a in the figure, and the pressure P□' through the throttle 11c is led to the left end spring chamber of the piston 11a,
When becomes higher, the piston 11a moves to the left to narrow the flow path,
When the pressure P2 becomes low, the piston 11. is moved to the right to widen the flow path and constantly supply a constant flow rate to the vent chamber 7.

The check valve 12 is also well known, and has a cranking pressure higher than the cranking pressure caused by the main spring 8 of the main piston 4, and causes the compressed oil to flow in the direction indicated by the arrow when peak pressure is generated at the exit robot B.

The balanced piston type relief valve 13 is a well-known type consisting of a balanced piston valve 13a and a poppet valve 13b, and releases excess oil in the circuit to always keep the circuit pressure constant.

When the pilot type pressure reducing valve shown in Fig. 4 is used with the circuit configuration shown in Fig. 2, when the switching valve Sv is switched to open the outlet side of the pressure reducing valve RV from the blocked state, the main piston 4 descends, but at that time, oil not only flows into the vent chamber 7 from the outlet port 3 side through the flow path 6 and orifice 5 in the main piston 4, but also from the inlet boat 2 side. 11, the descending speed is fast, and therefore the pressure drop (undershoot) on the exit boat 3 side is small, and its recovery time is also short.

Also, if the outlet side of the pressure reducing valve RV is blocked from the open state, the pressure P, 2 in the outlet boat 3 will become higher than the set pressure, but if this happens, the check valve 12 will open and pressurized oil will flow from the outlet port 3 to the vent chamber 7. Since the water flows in the direction of water, opens the balance piston valve 13a of the balance piston type relief valve 13, and quickly escapes from the drain boat 9, the generation of peak pressure is small.

When oil flows out from the vent chamber 7 as the main piston 4 rises, the conventional poppet valve 10 (first
Since there is almost no flow rate restriction such as that shown in FIG.

Japan - America As explained above, if the pilot type pressure reducing valve according to the present invention is used, there will be less undershoot of the outlet side pressure when the outlet side is opened from the blocked state, and the recovery will be quick. Further, when the outlet side is blocked from the open state, the peak of the outlet side pressure is reduced, and the settling time is also shortened.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional pilot type pressure reducing valve, Fig. 2 is a circuit diagram showing an example of a hydraulic circuit that drives a cylinder via a pilot type pressure reducing valve and a switching valve, and Fig. 6 is a sectional view of a conventional pilot type pressure reducing valve. FIG. 4 is a curve diagram of the change in outlet pressure of the pressure reducing valve RV when the switching valve S■ is switched from blocked to open and from open to blocked in the circuit shown in the figure. It is a schematic cross-sectional view. 1...Body 2...Inlet port 3...
Outlet port 4... Main piston 5... Orifice 7... Vent chamber 8... Main spring 9... Drain boat 10... Poppet valve (conventional pilot valve) 11... With pressure compensation Flow rate control valve 12...Check valve 13...Balance piston type relief valve (pilot valve) Figure 1 Figure 2 Figure 3 Procedural amendment (1st chapter) July 15, 1981 Commissioner of the Japan Patent Office Kazu Wakasugi Husband 1, Indication of the case Patent application No. 58-88769 2, Name of the invention Pilot type pressure reducing valve 3, Person making the amendment Relationship to the case Patent applicant 2-16-46 Minami Kamata, Ota-ku, Tokyo (338 )
Tokyo Keiki Co., Ltd. 4゜ Agent 1-20-5 Higashiikebukuro, Toshima-ku, Tokyo " is corrected to "cranking." Page 1, bottom line - page 2, line 1 (2 places) Page 6, lines 7-8 (2 places) (2) Same book, page 7, line 2 The statement "With pressure compensation......retained" in the first line of page 8 is corrected as shown in the attached sheet. (3) "Figure 4" in the drawing is changed to the corrected drawing in the attached sheet. 7. Attached document corrected drawing (Fig. 4) 1 copy (attached) The flow rate control valve with pressure compensation 11 is a known one, but the piston lla and the pressure-compensated flow control valve 11 are biased in the direction of opening the flow path. The pressure P1 at the inlet port 2 is guided to the chamber on the right end side of the piston 11a in the figure, and the pressure P1 through the orifice 11c is transferred to the left end of the piston 11a9. Lead to the side spring chamber, Pl or P
2 changes, the differential pressure across the throttle 11c p, -
When p,' = ΔP increases, the piston 11a moves to the left to narrow the flow path, and when the differential pressure ΔP decreases, the piston 11a moves to the right to widen the flow path, so that a constant flow rate is always supplied to the vent chamber 7.
supply to. The check valve 12 is also a known one, but it has a cranking pressure higher than the cranking pressure caused by the main spring 8 of the main piston 4, and causes the compressed oil to flow in the direction of arrow Y when peak pressure is generated at the exit robot B. . The balanced screw type relief valve 13 is a well-known type consisting of a balanced piston valve 13a and a poppet valve 13b, and releases excess oil from the vent chamber 7 to maintain a constant pressure in the vent chamber 7.

Claims (1)

[Scope of Claims] 1. A main piston that opens and closes a main flow path that communicates between the artificial bow 1- and an outlet port, and that has a flow path that communicates the outlet port with the vent chamber via an orifice; The main spring is housed and urges the main piston in the direction of opening the main flow path, and a pilot valve for setting pressure is inserted between the vent chamber and the drain boat, and the pressure at the outlet port is adjusted. In the pilot type pressure reducing valve that adjusts the set pressure to be lower than the pressure of the inlet port, the inlet port and the vent chamber are connected via a pressure-compensated flow control valve that always supplies a constant flow rate from the inlet boat to the vent chamber. , the outlet port and the vent chamber are connected by inserting a check valve that allows flow only from the outlet port toward the vent chamber and has a cranking pressure higher than the cranking pressure caused by the main spring of the main piston; , A pilot type pressure reducing valve characterized in that the pilot valve for pressure setting is a balanced piston type relief valve.