JPH042835B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to a valve device that can arbitrarily adjust the opening degree of a main valve, and in particular to a valve device with a servo function that adjusts the opening degree of a poppet valve or a sleeve valve. Regarding equipment.

[Prior art and its problems]

Conventionally, an orifice was provided between the front chamber and the rear chamber of the main valve to communicate these two chambers, and the rear chamber and the return circuit were connected via a switching valve, and by opening or closing the switching valve. Control valve mechanisms configured to open and close the main valve have been proposed (for example,
-20958 Publication). However, this type of control valve mechanism has the disadvantage that the opening of the seed valve cannot be adjusted to any intermediate position.

Therefore, the applicant proposed a poppet valve that has a poppet movably inserted into a hole in the valve body and is configured to change the opening degree of the valve passage depending on the lift amount of the poppet. A pilot spool is coaxially provided inside the poppet, and a control mechanism such as a solenoid for moving the pilot spool upward and downward is provided, and when the input signal to the control mechanism is zero, pump pressure acts on the upper end surface of the poppet. The poppet is configured such that when the pilot spool is lifted upward by applying an input signal, tank pressure or load pressure is applied to the upper end surface of the poppet, and the poppet is configured to be servo positioned according to the amount of movement of the pilot spool. We developed a valve poppet lift amount control mechanism and filed a patent application (Japanese Patent Application Laid-open No. 1983-65475). However, since the mechanism according to the patent application has a wide variety of servo oil passages provided in the valve housing, it has the disadvantage that the structure is complicated, and manufacturing is time-consuming and expensive.

[Purpose of the invention]

An object of the present invention is to provide a valve device with a built-in servo mechanism that has a simple structure and can adjust the opening degree of the pilot valve to an arbitrary position.

[Key points of the invention]

That is, in the valve device according to the present invention, a small-diameter shaft portion is provided at the rear of the main valve, and this small-diameter shaft portion extends into a back chamber adjacent to a rear chamber of the valve casing, and the tip of the small-diameter shaft portion An oil passage with an orifice is bored in the center of the main valve and its small diameter shaft, and the oil passage communicates the front chamber and the rear chamber of the valve casing with each other. At the same time, a variable orifice is provided in a part of the small diameter shaft portion held by the sleeve to communicate the oil passage to the back chamber via the sleeve, and a discharge path is provided in a part of the back chamber to communicate with the return circuit,
Furthermore, the valve opening degree is configured to be adjustable by providing a control means for displacing the sleeve in the axial direction.

That is, in the present invention, the main valve has a small diameter shaft protruding from the main valve, an oil passage with an orifice is provided inside the main valve and the small diameter shaft, and a variable orifice is provided in a part of this oil passage. By configuring the valve opening to be adjustable, it is possible to obtain a valve device with a simple configuration and stable operation, and the valve opening degree can be adjusted.

Therefore, in the valve device of the present invention, it is preferable that the sleeve is elastically mounted in the back chamber in the axial direction via a coil spring, and the sleeve is pressed and displaced by the control means against the spring elasticity. It is.

Further, it is preferable that the variable orifice provided between the sleeve and the small-diameter shaft portion of the main valve be configured to be fully open at the maximum retracted position of the sleeve. In this case, a spring can be inserted in the coil between the tip of the small-diameter shaft portion of the main valve and the sleeve.

Further, a piston is provided in the sleeve, facing the tip of the small diameter shaft of the main valve and always in contact with the rear end surface of the back chamber, further opening the oil passage of the small diameter shaft into the sleeve, By allowing pressure oil to flow into the sleeve, the back pressure against the main valve can be compensated for, and the position adjustment of the main valve can be achieved even more smoothly and reliably.

In the valve device of the present invention, various hydraulic control means, electric control means, and mechanical manual control means can be appropriately employed as the control means for displacing the sleeve.

[Embodiments of the invention]

Next, embodiments of the valve device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a main part showing an embodiment of a valve device according to the present invention. That is, in Figure 1,
Reference numeral 10 indicates a valve casing, and 12 indicates a poppet that constitutes a main valve provided within the valve casing 10. However, the valve chamber is partitioned by the poppet 12 into a front chamber 14, a rear chamber 16, and an intermediate chamber 18, and the front chamber 14 communicates with the high pressure circuit.
An intermediate chamber 18, which can be disconnected from communication with the rear chamber 16 by means of a poppet 12, communicates with the return circuit. Further, at the rear of the poppet 12, there is a small diameter shaft portion 22 extending from the rear chamber 16 to the back chamber 20.
will be provided. On the other hand, the back chamber 20 is provided with a sleeve 24 that abuts the rear end surface and slidably inserts and holds the small diameter shaft portion 22 of the poppet 12.
Therefore, this sleeve 24 has a coil spring 26 attached to its outer periphery so as to elastically abut against the rear end surface of the back chamber 26, and a coil spring 28 is also inserted inside the sleeve 24 to prevent the poppet 12 from moving. Front chamber 14
It is configured to be elastically pressed to the side.

An oil passage 30 extending in the axial direction is provided inside the poppet 12 and its small diameter shaft portion 22, and one end of this oil passage 30 opens into the front chamber 14 through an orifice 32. Further, a portion of the oil passage 30 is configured to directly communicate with the rear chamber 16, and a variable orifice 34 is formed in a portion held by the sleeve 24 to communicate with the back chamber 20.

Further, a through hole 36 is formed in a part of the valve casing 10 at the rear end of the sleeve 24 that is in contact with the rear end surface of the back chamber 20, and the pilot plunger 38 is inserted into the through hole 36. The sleeve 24 is configured to be moved forward by the pilot plunger 38 against the elasticity of the coil spring 26. Note that the valve casing 10 includes the back chamber 2.
A discharge passage 40 communicating with 0 is provided, and this discharge passage 40
is configured to communicate with the return circuit. Further, as a control means for moving the pilot plunger 38 to a predetermined position, for example, a hydraulic control means using pilot pressure or a proportional solenoid valve, an electric control means using a solenoid, a pulse motor, a rotary solenoid, etc., or a micrometer head, etc. Mechanical manual control means using push-pull wires or the like may be employed as appropriate.

Next, the operation of the valve device of the above-described embodiment will be explained.

First, in the state shown in FIG. 1, the pilot plunger 38 is set at the maximum retraction position, and the rear end of the sleeve 24 is in contact with the rear end surface of the back chamber 20. At this time, the variable orifice 34 of the oil passage 30 bored through the poppet 12 and its small diameter shaft portion 22 is fully open to the back chamber 20. Therefore, when pressure oil acts on the front chamber 14, a part of this pressure oil flows into the rear chamber 16 and the back chamber 20 through the oil passage 30 and flows out to the outside through the discharge passage 40. The internal pressure of the chamber 16 is not increased, and the poppet 12 is retracted by the hydraulic pressure acting on the front chamber 14. In this case, as the small diameter shaft portion 22 retreats with respect to the sleeve 24, the opening degree of the variable orifice 34 gradually becomes smaller, and when the variable orifice 34 becomes almost closed, most of the pressure oil flows through the oil passage 30. Flows into the rear chamber 16, and as a result, the internal pressure of the rear chamber 16 is increased, and with the action of the coil spring 28, it is balanced with the pressure on the front chamber 14 side, and the poppet 12 is stabilized by maintaining a predetermined opening degree. .

Next, when the pilot plunger 38 is moved forward by a predetermined control means, the sleeve 24 moves forward and the poppet 12 moves forward with its small diameter shaft portion 2.
2 is pushed back toward the front chamber 14 by the pressing elasticity of the coil spring 28 acting on the end of the coil 2, and is stabilized in the positional relationship of the variable orifice 34 described above. That is, by moving the sleeve 24 forward in this manner, the opening degree of the poppet (main valve) 12 that cuts off communication between the front chamber 14 and the intermediate chamber 18 can be freely adjusted.

FIG. 2 shows another embodiment of the valve device according to the invention. For convenience of explanation, the same reference numerals are given to the same components as those of the valve device shown in FIG. 1, and detailed explanation thereof will be omitted. That is, in this embodiment, since in the previously described embodiment, the pressure oil does not act on the cross-sectional area equivalent to the small diameter shaft portion 22 of the poppet 12, the small diameter shaft portion 24 inserted into the sleeve 24 is used to compensate for this. An oil passage 30 is opened at the end of the shaft portion 22, and this sleeve 2
A piston 42 is disposed at the rear end of the back chamber 20, and the piston 42 is configured to directly abut against the rear end surface of the back chamber 20. With this configuration, the pressure oil acts appropriately on the small diameter shaft portion 22 of the poppet 12.
The pressure balance with the front chamber 14 side can be further stabilized. Furthermore, depending on the position of the sleeve 24 in relation to the variable orifice 34, the poppet 1
The opening adjustment action of No. 2 is exactly the same as in the embodiment described above.

〔Effect of the invention〕

As is clear from the embodiments described above, a small diameter shaft is provided protruding from the rear part of the poppet, and this small diameter shaft is surrounded and held by a sleeve whose position can be adjusted freely, while extending from the poppet to the small diameter shaft. An oil passage with an orifice is provided in the center, and this oil passage opens into the rear chamber of the poppet, and in the part held by the sleeve, the sensitivity changes depending on the relative position between the small diameter shaft and the sleeve. By providing a variable orifice to communicate with the back chamber, and further providing a discharge passage that partially communicates the back chamber with the rear chamber and communicates a return circuit, the sleeve and the small diameter shaft portion can be connected to each other. The poppet can be adjusted to any desired opening under the action of variable orifices located between them. That is, not only can the adjustment of the variable orifice be easily performed using a suitable control means for the sleeve, but also the opening degree adjustment of the poppet constituting the main valve can be realized smoothly and with high precision.

Further, the valve device according to the present invention is provided with a small diameter shaft portion protruding from a poppet constituting the main valve, and a sleeve that surrounds and holds one end of this small diameter shaft portion, so that the small diameter shaft portion and the sleeve are provided. The main structure is to form a variable orifice between the valve casing and the valve casing, and since there is almost no need to provide an oil passage, the structure is simple and can be manufactured at low cost.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be applied to various types of valve devices with adjustable opening, and other embodiments of the present invention can be applied. Of course, various design changes may be made without departing from the spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing one embodiment of a valve device according to the present invention, and FIG. 2 is a sectional view of a main part showing another embodiment of a Musa device according to the present invention. 10... Valve casing, 12... Main valve (poppet), 14... Front chamber, 16... Rear chamber, 18... Intermediate chamber, 20... Back chamber, 22... Small diameter shaft portion, 24...
... Sleeve, 26 ... Coil spring, 28 ... Coil spring, 30 ... Oil path, 32 ... Orifice, 3
4... variable orifice, 36... through hole, 38...
...Pilot plunger, 40...Discharge passage, 42
……piston.

Claims (1)

[Claims] 1. A small-diameter shaft is provided at the rear of the main valve, and this small-diameter shaft extends into a back chamber adjacent to the rear chamber of the valve casing, and the tip of the small-diameter shaft is fitted into a sleeve. An oil passage with an orifice is bored in the center of the main valve and its small diameter shaft, and the oil passage communicates the front chamber and the rear chamber of the valve casing with each other, and the sleeve A variable orifice that communicates the oil passage with the back chamber is provided in a part of the small diameter shaft held by the sleeve through a sleeve, a discharge path that returns to the back chamber is provided in a part of the back chamber, and the sleeve What is claimed is: 1. A valve device whose opening degree can be adjusted, characterized in that it is provided with a control means for displacing the valve in the axial direction. 2. In the valve device according to claim 1, the sleeve is elastically mounted in the back chamber in the axial direction via a coil spring, and the control means presses and displaces the sleeve against the spring elasticity. A valve device consisting of: 3. In the valve device according to claim 1, the variable orifice provided between the sleeve and the small diameter shaft portion of the main valve is configured to be fully open at the maximum retracted position of the sleeve. Device. 4. The valve device according to claim 1, wherein a coil spring is inserted between the tip of the small diameter shaft portion of the main valve and the sleeve. 5. In the valve device according to claim 1, a piston is provided in the sleeve, facing the tip of the small-diameter shaft portion of the main valve and always in contact with the rear end surface of the back chamber,
Furthermore, the valve device is configured such that the oil passage of the small diameter shaft portion is opened into the sleeve.