JPH02245586A - pressure control valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure control valve with a pilot poppet.

[Conventional technology]

A pressure control valve disclosed in Japanese Utility Model Application Publication No. 59-98168 is known.

That is, as shown in FIG. 3, the piston 4 is passed through a relief poppet 3 that blocks communication between the high pressure section 1 and the low pressure section 2, and the high pressure section 1 is communicated with the back pressure chamber 5. The pilot poppet 6 connects and disconnects the part 2 with the spring 7.
This is a pressure control valve in which the main poppet 3 operates to communicate the high pressure section 1 to the low pressure section 2 after the pilot poppet 6 operates to communicate when the high pressure section 1 reaches a set pressure or higher.

[Problem to be solved by the invention]

In such a pressure control valve, when the piston 4 is pushed to the right and the central passage 8 is blocked by the protrusion 6a of the pilot poppet 6, back pressure is generated from the passage 9 formed between the piston 4 and the relief poppet 3. The flow flows into chamber 5, and the pressure difference before and after the relief poppet 3 becomes large, causing the relief poppet 3 to
moves the high pressure section 1 to a position where it communicates with the low pressure section 2.

For this reason, the relief poppet 3 moves after a time delay from when the pilot poppet 6 opens to when the piston 4 contacts the protrusion 6a and closes the central passage 8.
The time from when the high pressure section 1 reaches the set pressure until the relief operation is performed becomes long, and the relief response becomes poor.

In addition, in the above-mentioned pressure control valve, when the pressure in the high pressure section 1 drops below the pressure in the low pressure section 2, the relief poppet 3 and the suction poppet a move to suck pressure oil from the low pressure section 2 into the high pressure section 1. When the pressure in the high pressure section 1 increases, the piston 4 moves to the right and comes into contact with the protrusion 6a, thereby closing the central passage 8, which slows down the return of the relief poppet 3 and the suction poppet a.

Therefore, an object of the present invention is to provide a pressure control valve that can solve the above-mentioned problems.

[Means and effects for solving the problem] The central passage that communicates the high pressure part and the back pressure chamber is made to communicate through the orifice when the piston moves slightly toward the back pressure chamber, so that the high pressure part is connected to the set pressure or higher. This is a pressure control valve in which the relief poppet immediately operates in relief when the pilot poppet opens.

〔Example〕

As shown in FIG. 1, a suction poppet 1 is inserted into a cylindrical body 10
1 is fitted and inserted, and the distal end of the cylindrical body 12 screwed onto the cylindrical body 10 is fitted into the proximal large diameter portion 11a of the suction poppet 11,
A relief poppet 13 is fitted into the small diameter portion 11b at the tip of the suction poppet 11.
A piston 14 passes through the interior, and a spring 1 is inserted between the flange 14a of the piston 14 and the cylinder body 12.
5, the relief poppet 13 is pressed against the seat seat 16 by the piston 14, and blocks off the high pressure port 17 and the low pressure boat 18. A central passage 24 consisting of an orifice 22 and a through hole 23 is formed at the axis of the piston 14 and communicates with the high pressure section 20 and a back pressure chamber 25, which is connected to the pilot poppet 26. A lateral hole 27 is formed in the longitudinally intermediate portion of the piston 14 to open the central passage 24 to the outer circumferential surface, and is communicated with and cut off from the low pressure portion 21. When the pilot poppet 2G is closed, the lateral hole 27 opens to the high pressure boat 17. ing.

When the pressure in the high pressure section 20 exceeds the set pressure, the high pressure oil flows into the back pressure chamber 25 through the side hole 27 and the through hole 23, pushes open the pilot poppet 26, and flows out into the low pressure section 21. Pressure is generated and the piston 14 moves to the right against the spring 15.

As a result, the side hole 27 is closed by the relief poppet 13, so the pressure oil in the high pressure section 20 flows into the back pressure chamber 25 through the orifice 22 and the through hole 23, and the differential pressure before and after the relief poppet 13 increases. The relief poppet 13 moves to the right and communicates the high pressure port 17 with the low pressure boat 18.

That is, the relief operation is performed before the piston 14 comes into contact with the protrusion 26a of the pilot poppet 26.

FIG. 2 shows a modification in which a small diameter portion 14b is formed at the tip end of the piston 14, a central passage 24 is formed by opening into the small diameter portion 14b, and a horizontal hole 30 is formed in the small diameter portion 13a at the tip end of the relief poppet 13. An orifice 31 is formed, and when the piston 14 moves slightly, the horizontal hole 30 and the small diameter portion 14b are cut off, allowing pressurized oil in the high pressure section to flow through the orifice 31 and into the central passage 24.

〔Effect of the invention〕

When the piston 14 moves slightly toward the back pressure chamber 25, the high pressure section 2
Since zero pressure oil flows into the back pressure chamber 25 through the orifice, the differential pressure across the relief poppet 14 becomes large, and the relief poppet 14 communicates between the high pressure section 20 and the low pressure section 21.

Therefore, as soon as the pilot poppet 6 opens, the relief poppet 14 performs a relief operation, and the time from when the high pressure section 20 reaches the set pressure until the relief operation is performed is short, and relief responsiveness is improved.

Furthermore, even if the pressure in the high pressure section increases during suction operation, the central passage of the piston 14 is not blocked, so the relief poppet 1
4 and the suction poppet 11 can be returned quickly.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a pressure control valve showing an embodiment of the present invention, FIG. 2 is an explanatory view of main parts of a modified example, and FIG. 3 is a sectional view of a conventional example. 11 is a suction poppet, 13 is a piston, 14 is a relief poppet, 20 is a high pressure section, 21 is a low pressure section, 25 is a back pressure chamber, and 26 is a relief poppet.

Claims (1)

[Claims] A suction poppet 11 that connects and disconnects the high pressure section 20 and the low pressure section 21, a relief poppet 13 that is provided within the suction poppet 11 and connects and disconnects the high pressure section 20 and the low pressure section 21, and the relief poppet 13. In the pressure control valve, the piston 14 is provided with a piston 14 that passes through the piston 14 and communicates the high pressure section 20 with the back pressure chamber 25, and a pilot poppet 26 that communicates and blocks the back pressure chamber 25 with the low pressure side 21.
When piston 14 is in a predetermined position, high pressure section 20 and back pressure chamber 25 are communicated through a side hole, and when piston 14 moves slightly toward back pressure chamber 25 due to the pressure of high pressure section 20, a central passage is formed that communicates through an orifice. A pressure control valve characterized by: