JPH0660702B2 - Control valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control valve for controlling pressure oil such as a hydraulic elevator, and more particularly to improving the operation accuracy of the control valve.

[Conventional technology]

FIG. 3 is a sectional view showing a conventional control valve similar to that shown in Japanese Utility Model Publication No. 57-200774, for example.
(1) is a sleeve with a valve chamber (1a) formed in the longitudinal direction, (2) is a valve chamber
A spool provided in (1a) and slidably arranged in the axial direction, (3) is a first back chamber formed at one end of the sleeve (1),
(4) is a second back chamber formed at the other end of the sleeve (1) facing the first back chamber (3), and (5) is provided in the sleeve (1) and is provided in the valve chamber (1
a high-pressure port that communicates with a) and is located near the first back chamber (3),
(6) is provided on the sleeve (1) and communicates with the valve chamber (1a).
The high pressure port (5) near the back chamber (2) is located at a low pressure port, and the (7) is a sleeve formed by the concave portion of the sleeve (2) and the high pressure port (5). A push spring provided in the back chamber (4) for pressing the spool (2), (9) a first pilot circuit communicating with the first back chamber (3), and (10) a second back chamber (4). Second pilot circuit in communication, (11) is the first pilot circuit
The variable throttle valve provided in (9) and (12) are oil tanks provided at the circuit end on the low pressure port (6) side.

The conventional control valve is configured as above, and the pressure oil is a high pressure port.
(5), Chiyoke (7), Low pressure port (6) to oil tank (12), and also pressure oil from the first pilot circuit (9) to the first back chamber (3) through the variable throttle valve (11). And the drain circuit is formed from the second back chamber (4) by the second pilot (4). And by the operation of the variable throttle valve (11), etc., the force by the pressure oil acting on the first back chamber (3) side of the spool (2),
The area of the yoke (7) is changed by sliding displacement of the spool (2) according to the strength relationship of the force acting on the spool (2) by the push spring (8), and the flow rate of the pressure oil passing through the choke (7) and The pressure on the high pressure port (5) side is controlled by changing the pressure on the high pressure port (5) side.

[Problems to be solved by the invention]

In the conventional control valve as described above, in the high pressure port (5), the first portion is provided from the gap between the sleeve (1) and the spool (2).
Although the pressure oil leaks to the back chamber (3), the amount of leakage changes due to the change in the pressure on the high pressure port (5) side and the viscosity change of the pressure oil, which causes the sliding displacement of the spool (2). There is a problem that the required control action cannot be obtained because the operating speed changes.

It should be noted that it is conceivable to provide a sealing material such as an O-ring on the sleeve (1) or the like in order to prevent pressure oil from leaking from the fitting portion of the sleeve (1) and the spool (2), but the spool is used for the sealing material.
As the sliding resistance of (2) increases, the sliding resistance of the spool (2) changes due to changes in the sealing pressure and temperature changes of the pressure oil, making the control action more unstable.

The present invention has been made in order to solve the above problems, and prevents disturbance of the control action due to change in the operating speed of the spool due to leakage of pressure oil from the fitting portion of the sleeve and the spool, and operates well. The purpose is to obtain a control valve that does.

[Means for solving problems]

In the control valve according to the present invention, the drain passage is provided from the fitting sliding portion of the sleeve and the spool to the low pressure port side.

[Action]

In the present invention, the pressure oil leaking from the fitting sliding portion of the sleeve and the spool flows out to the low pressure port side through the drain passage and does not flow into the back chamber of the valve chamber.

〔Example〕

FIG. 1 is a view corresponding to FIG. 3 showing an embodiment of the control valve according to the present invention, in which the same symbols as in FIG.
3) is a groove that is arranged on the relative sliding surface between the valve chamber (1a) and the spool (2) and is recessed in the spool (2), and has an annular shape that is orthogonal to the axis of the spool (2). It is provided on the outer circumference of the surface. (14) is a through hole that is provided at a position facing the low pressure port (6) of the spool (2) and intersects the axis of the spool (2), and (15) is orthogonal to the axis of the spool (2). Annular groove (13)
Through-holes provided from the groove bottom on one side to the groove bottom on the other side, (16)
Is a pipe line provided along the axis of the spool (2) and having both ends open to the through hole (14) and the through hole (15), respectively (1
Reference numeral 7) is a drain flow path consisting of the groove (13), the through holes (14) and (15), and the pipe line (16).

In the control valve configured as described above, the sleeve (1)
Since the pressure oil that has entered the mating sliding part of the spool (2) and the spool (2) from the high pressure port (5) side enters the groove (13) and flows out through the drain flow path (17) to the low pressure port (6) side. No leakage to the back room (3).

Further, the pressure oil in the first back chamber (3) from the first pilot circuit (9) also enters the fitting sliding portion of the sleeve (1) and the spool (2), but passes through the drain flow passage (17) and is a low pressure port. It flows to the (6) side. Therefore, the spool (2) slides and displaces due to the pressure oil being supplied to and discharged from the first back chamber (3) by the first pilot circuit (9), but the influence of the pressure oil leaked from the high pressure port (5) side Is prevented from affecting the sliding displacement of the spool (2). Therefore, it is possible to realize a control valve that can obtain a normal sliding displacement operation of the spool (2) and can obtain a required control action of pressure oil. In addition,
The normal sliding displacement operation of such a spool (2) has the same effect as when a sealing material is inserted between the sleeve (1) and the spool (2), and the sliding resistance is increased. With a small and simple device configuration, it is possible to obtain the required action easily with high accuracy at low cost.

FIG. 2 shows another embodiment of the control valve according to the present invention. In the figure, the same symbols as in FIG. 1 show the corresponding parts, and (13) shows the relative relationship between the valve chamber (1a) and the spool (2). Valve chamber (1a) with valve on sliding surface
Is a groove that is formed in an annular shape that is orthogonal to the axis of the spool (2) and is provided around the inner surface of the valve chamber (1a). (16) is provided on the sleeve (1), and one end of the sleeve (1) opens at the bottom of the groove (13).
The other end is a conduit opened to the low pressure port (6) side, and (17) is a groove (1
3), a drain passage consisting of a pipe (16).

That is, also in this embodiment, the pressure oil that has entered the fitting sliding portion of the sleeve (1) and the spool (2) from the high pressure port (5) side enters the groove (13) and is low pressure from the drain flow passage (17). It flows out to the port (6) side. Therefore, although detailed description is omitted, it is obvious that the same operation as that of the embodiment of FIG. 1 can be obtained in this embodiment as well.

〔The invention's effect〕

As described above, according to the present invention, the fitting sliding portion of the sleeve and the spool is provided with the drain passage for allowing the pressure oil that has entered from the high pressure port side to flow out to the low pressure port side. Therefore, when the spool slides and displaces due to the supply and discharge of pressure oil to and from the back chamber by the pilot circuit, the spool slides and displaces without being affected by leaked pressure oil from the high pressure port side to the back chamber. It realizes a control valve that can be normally displaced and easily obtain the required control action.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a control valve according to the present invention, FIG. 2 is a view corresponding to FIG. 1 showing another embodiment of the control valve according to the present invention, and FIG. 3 shows a conventional control valve. It is a figure equivalent to FIG. In the figure, (1) is a sleeve, (2) is a spool, (3) is a first back chamber, (5) is a high pressure port, (6) is a low pressure port, (7) is a chioke, and (9) is a first A pilot circuit, (13) is a groove, and (17) is a drain passage. The same or corresponding parts in the drawings are designated by the same reference numerals.

Claims (1)

[Claims] 1. A spool which is slidable in an axial direction is provided in a sleeve, pressure oil is introduced into a back chamber facing the spool end portion by a pilot circuit, and the supply and discharge of this pressure oil is operated to operate the spool. Is slidably displaced to change the area of the cheek portion of the flow path formed by both the sleeve and the spool, so that the high pressure port side provided on one side of the cheek portion and the low pressure port side provided on the other side In the control valve for controlling the pressure or the flow rate of the above pressure oil, one end is opened in an annular groove that is recessed in one of the two relative sliding surfaces of the above and intersects the axis line and extends along the peripheral surface, When the groove is provided on the sleeve, the groove is provided on the sleeve when the groove is provided on the spool, and the drain is provided at the other end on the low pressure port side at the other end. Control valve.