JP2021004620A - Control valve - Google Patents

Abstract

To constitute a control valve for suppressing a flow force, in a constitution in which a working fluid flows to a flow passage in a sleeve from a land part of a spool.SOLUTION: A control valve comprises a sleeve 2 formed with a pump port 2p, and a spool 3 slidably and movably accommodated in the sleeve 2, and formed with a land part 3a at an external periphery. The spool 3 is freely operable to a block position in which the land part 3a blocks a flow of a working fluid, and a release region for sending out the working fluid to the land part 3a. The sleeve 2 has a flow passage hole S whose diameter is larger than an outside diameter of the land part 3a so as to receive the working fluid which has passed through the land part 3a, and the flow passage hole S comprises an inclined guide face Sa having a posture inclined to an axial core X so as to make the working fluid flow to a direction separating from the axial core X with an opening edge for receiving the working fluid as a reference.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control valve that controls hydraulic oil by operating a spool.

As the control valve having the above configuration, Patent Document 1 describes a configuration in which the generation of flow force is suppressed and the operation of the spool is stabilized.

That is, in Patent Document 1, a notch is formed by cutting out a part of the land portion of the spool, and the angle at which the hydraulic oil flows through the notch is set to a preset free inflow angle. ..

JP-A-2002-122249

However, in the technique of Patent Document 1, the flow path through which the hydraulic oil flows from the land portion of the spool in the sleeve accommodating the spool is a cylindrical inner peripheral surface centered on the axis of the spool accommodating space of the sleeve. It has a shape having a wall portion orthogonal to the axis. Therefore, when the hydraulic oil flows from the edge of the land portion of the spool into the flow path, the hydraulic oil collides with the inner peripheral wall or the wall portion, and there is a problem that a flow force is generated due to this collision.

For this reason, a control valve that suppresses the flow force generated when the hydraulic oil flows from the land portion of the spool to the flow path inside the sleeve is required.

The characteristic configuration of the control valve according to the present invention is a sleeve in which a pump port to which hydraulic oil is supplied is formed and a spool accommodating space for accommodating a spool is formed along the axis, and a slide into the spool accommodating space. A spool that is movably accommodated and has a land portion formed on the outer periphery thereof is provided, and the spool has a closed position in which the land portion blocks the flow of hydraulic oil supplied to the pump port, and a sliding movement of the spool. The hydraulic oil supplied to the pump port is operably configured in an open area for being sent out from the edge of the land portion, and the spool accommodating space has a spool hole having an inner diameter that is in close contact with the outer periphery of the land portion and the spool hole. The shaft has a flow path hole having an inner diameter larger than the outer diameter of the land portion so as to receive the hydraulic oil that has passed through the land portion, and the flow path hole is based on the opening edge for receiving the hydraulic oil. The point is that it is provided with an inclined guide surface that is inclined with respect to the shaft core so that hydraulic oil flows in a direction away from the core.

According to this characteristic configuration, when the hydraulic oil from the pump port is supplied to the flow path hole from the edge of the land portion as the spool operates, the hydraulic oil flows along the inclined guide surface of the flow path hole. become. Since this inclined guide surface is inclined with respect to the shaft core and the hydraulic oil flows in a direction away from the shaft core, for example, a cylindrical inner peripheral surface or a shaft core whose flow path hole is centered on the shaft core. Compared with the configuration in which the wall portion having the posture orthogonal to the above is formed, the flow force can be suppressed without the hydraulic oil colliding with the inner wall of the flow path hole.
Therefore, a control valve that suppresses the flow force when the hydraulic oil flows from the land portion of the spool to the flow path inside the sleeve is configured.

Here, it will be described based on the measurement result that the flow force of the control valve having the present characteristic configuration is suppressed as compared with the control valve having the conventional configuration. In FIG. 4, in the control valve having this characteristic configuration in which the flow force is suppressed, the current supplied to the electromagnetic solenoid is arbitrarily set, and when the set current is supplied and the spool is stopped (balanced), the hydraulic oil is used. The measurement to acquire the pressure received by the spool is repeated, and the measurement result is shown in the graph as IP characteristics. The IP characteristics are given by the balance formula of "solenoid thrust = spring force + spool receiving pressure", and from FIG. 4, in the control valve having this characteristic configuration, the relationship between the current supplied by the electromagnetic solenoid and the pressure acting on the spool is linear. It can be understood that the IP characteristics are in a direct proportional relationship in which the influence of the flow force is suppressed.

On the other hand, FIGS. 5 and 6 show the characteristics (IP characteristics) of the control valve having the conventional configuration affected by the flow force. In the graph of FIG. 5, it can be seen that the pressure with respect to the current has a stepped IP characteristic that takes a plurality of values, and in the graph of FIG. 6, it can be seen that the pressure is hunted when the current increases. When the IP characteristics are not in a direct proportional relationship as described above, it is considered that the IP characteristics do not follow the above-mentioned balance equation but follow the equation of "solenoid thrust = spring force + spool receiving pressure + flow force".
It can be understood that the flow force is suppressed in the control valve having this characteristic configuration as compared with the conventional configuration in which the influence of the flow force is large. In particular, even in a hydraulic system such as an electromagnetic proportional valve that controls a cylinder or a clutch, which requires high accuracy in the relationship between the current supplied to the electromagnetic solenoid and the oil pressure, the control valve of the present invention can be used for the entire system. It is possible to improve the operating accuracy and stability.

As a configuration added to the above configuration, the flow path hole with respect to the inclined guide surface and the inclined guide surface so as to guide the hydraulic oil flowing along the inclined guide surface in a direction approaching the axis. It may be composed of a reversely inclined guide surface that is inclined in the opposite direction.

According to this, the hydraulic oil that flows from the edge of the spool along the inclined guide surface of the flow path hole flows from the inclined guide surface to the reverse inclined guide surface, and flows along this reverse inclined guide surface, so that the hydraulic oil is strong. There is no collision, and the phenomenon that flow force is generated on this reversely inclined guide surface is suppressed. Further, the hydraulic oil flowing on the reversely inclined guide surface comes into contact with the spool in a posture inclined to the shaft core, and the component force acting on the spool from the hydraulic oil due to this contact is in the direction of releasing the spool. To make the opening of the oil smooth.

As a configuration added to the above configuration, a notch formed in a groove shape from the opening edge toward the center of the land portion in the direction along the shaft core may be formed in a part of the land portion.

According to this, the hydraulic oil can be supplied to the flow path hole through the notch before the timing when the hydraulic oil flows from the edge of the land portion to the flow path hole as the spool operates, so that the hydraulic oil flowing to the flow path hole can be supplied. It is possible to suppress a rapid increase and suppress the flow force even better.

It is sectional drawing of the control valve which a spool is in a closed position. It is sectional drawing of the control valve which a spool is in an open area. It is a perspective view of a spool. It is a graph which shows the relationship between the electric current and the pressure of the control valve of this invention. It is a graph which shows the relationship between the electric current and the pressure of a conventional control valve. It is a graph which shows the relationship between the electric current and the pressure of a conventional control valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the control valve V includes a sleeve 2 fitted in a valve hole 1a of a valve housing 1 and a spool 3 housed in the sleeve 2 so as to be slidable.

In this control valve V, the spool 3 is held at the closed position shown in FIG. 1 by the urging force of the spring 4. Further, the control valve V includes an electromagnetic solenoid (not shown) outside the valve housing 1, and the spool 3 is opened on the open side (not shown) against the urging force of the spring 4 by the pressing force of the plunger 5 of the electromagnetic solenoid. It is configured to slide to the right side in FIGS. 1 and 2) and apply a pilot pressure to an external controlled object via a pilot flow path 1b formed in the valve housing 1.

In particular, the electromagnetic solenoid is configured so that the plunger 5 projects and operates by an amount proportional to the supplied current value, and by operating the spool 3 with the pressing force of the plunger 5, the control valve V changes to the current value. Obtain the corresponding pilot pressure.

As shown in FIGS. 1 to 3, a land portion 3a for controlling hydraulic oil is formed on the spool 3. Further, the spool 3 has a disc portion 3b having a diameter larger than that of the land portion 3a formed at the outer end (right end in FIGS. 1 and 2). A pump-side groove 3c is formed on the side of the spool 3 opposite to the disc portion 3b with reference to the land portion 3a, and a discharge-side groove 3d is formed at an intermediate position between the land portion 3a and the disc portion 3b.

A pump port 2p to which hydraulic oil is supplied is formed on the sleeve 2. Further, the spool 3 is accommodated in the spool accommodating space formed along the axis X of the sleeve 2. The pump port 2p communicates with the pump-side groove 3c of the spool 3.

The spool accommodation space has a spool hole 2a with an inner diameter slightly larger than the outer diameter of the land portion 3a, and an inner diameter larger than the outer diameter of the land portion 3a so as to receive hydraulic oil. It has a flow path hole S.

[Spool position]
This control valve V is maintained at the closed position shown in FIG. 1 when the electromagnetic solenoid is not driven. At this closed position, the land portion 3a enters the inner circumference of the spool hole 2a, so that the hydraulic oil from the pump port 2p does not flow into the flow path hole S, and the disk portion 3b of the spool 3 is the outer end of the sleeve 2. The hydraulic oil is not discharged from the flow path hole S by coming into contact with (the right end in FIGS. 1 and 2).

Further, when the electromagnetic solenoid is driven, the spool 3 is set in the open region shown in FIG. Since the operating amount of the spool 3 of the control valve V is determined in proportion to the current value supplied to the electromagnetic solenoid, the open region is not limited to the position shown in FIG. 2. Therefore, when the electromagnetic solenoid is driven, the spool 3 is opened. Is set to any position included in the open area.

[Suppression of flow force]
In this control valve V, as shown in FIGS. 1 to 3, when the spool 3 is set in the open region, the spool 3 is set to an appropriate position by suppressing the influence of the flow force and is targeted. The shape of the flow path hole S is set so that the pilot pressure can be obtained, and the land portion 3a is provided with the notch N.

That is, the flow path hole S is provided with an inclined guide surface Sa in a posture in which the flow path hole S is inclined with respect to the shaft core X so as to guide the hydraulic oil in a direction away from the shaft core X with reference to the opening edge for receiving the hydraulic oil. , The reverse inclined guide surface that smoothly connects to the inclined guide surface Sa so as to guide the hydraulic oil flowing along the inclined guide surface Sa in the direction approaching the axis X, and inclines in the opposite direction to the inclined guide surface Sa. It has Sb.

In this control valve V, a notch N having a groove shape is formed in the land portion 3a from the left edge in FIGS. 1 and 2 toward the center of the land portion 3a. Notches N are formed at a plurality of locations (in the embodiment, two locations facing each other across the shaft core X), and by cutting out a part of the land portion 3a, a groove shape having a posture along the shaft core X is formed. It is formed.

With such a configuration, the spool 3 is operated by the pressing force of the plunger 5 accompanying the drive of the electromagnetic solenoid, and the edge of the land portion 3a approaches the opening edge of the flow path hole S for receiving the hydraulic oil. When the edge of the land portion 3a approaches the opening edge in this way, the hydraulic oil from the pump port 2p flows through the plurality of notches N and is supplied to the flow path hole S. Although the amount of the hydraulic oil initially supplied in this way is small, the flow force is suppressed because the hydraulic oil flows along the inclined guide surface Sa.

Next, when the edge of the land portion 3a reaches a position in the flow path hole S that exceeds the opening edge for receiving the hydraulic oil and enters the flow path hole S, the edge of the land portion 3a operates into the flow path hole S. Oil will flow. When the hydraulic oil flows into the flow path hole S in this way, a part of the hydraulic oil from the pump port 2p flows along the groove 3c on the pump side, and further comes into contact with the land portion 3a from the shaft core X. Since it tends to flow in the direction of separation, most of the hydraulic oil flows along the inclined guide surface Sa of the flow path hole S.

Since such a flow of the hydraulic oil is smooth and does not collide with the inclined guide surface Sa, a reaction force does not act on the spool 3 via the hydraulic oil, and the flow force is suppressed. Further, the hydraulic oil that has flowed along the inclined guide surface Sa will then flow along the reverse inclined guide surface Sb, and the hydraulic oil will collide with the reverse inclined guide surface Sb even when flowing in this way. No, the flow force is suppressed.

Further, the hydraulic oil flowing on the reverse inclination guide surface Sb comes into contact with the spool 3 in a posture inclined to the shaft core X, and the component force acting on the spool 3 from the hydraulic oil due to this contact releases the spool 3. Therefore, the spool 3 can be smoothly opened.

As shown in FIG. 4, the IP characteristic of the control valve V of the present invention is that the current supplied to the electromagnetic solenoid and the pressure acting on the spool 3 have a direct proportional relationship, and the influence of the flow force is well suppressed. Can be understood. On the other hand, in the control valve having the conventional configuration, as shown in FIGS. 5 and 6, there is a region in which the current supplied to the electromagnetic solenoid and the pressure acting on the spool 3 are not in a proportional relationship, and the flow force is increased. It can be understood that the influence is appearing.

As a result, even in a hydraulic system such as an electromagnetic proportional valve that controls a cylinder or a clutch, which requires high accuracy in the relationship between the current supplied to the electromagnetic solenoid and the oil pressure, the control valve of the present invention provides the entire system. It is possible to improve the operation accuracy and stability of the.

[Another Embodiment]
The present invention may be configured as follows in addition to the above-described embodiment (those having the same functions as those in the embodiment are designated by the same number and reference numeral as those in the embodiment).

(A) In this control valve V, it is not always necessary to form a notch N, and the shape of the inner surface of the flow path hole S is not limited to the shape shown in FIGS. 1 and 2.

(B) The control valve V shown in the embodiment has a configuration in which the hydraulic oil supplied from the land portion 3a to the flow path hole S is discharged from the end portion of the sleeve 2, but instead of this, the control valve V is a control valve. A port for communicating V with the flow path hole S may be formed in the sleeve 2. In such a configuration, only the inclined guide surface Sa may be provided without the reverse inclined guide surface Sb.

(C) The control valve V may be configured to simply supply and discharge hydraulic oil.

The present invention can be used as a control valve that controls hydraulic oil by operating a spool.

2 Sleeve 2a Spool hole 2p Pump port 3 Spool 3a Land part S Flow path hole Sa Tilt guide surface Sb Reverse tilt guide surface N Notch X Shaft core

Claims (3)

A sleeve in which a pump port to which hydraulic oil is supplied is formed, and a spool storage space for accommodating spools is formed along the axis.
It is provided with a spool that is slidably accommodated in the spool accommodating space and has a land portion formed on the outer periphery thereof.
The spool sends out the hydraulic oil supplied to the pump port from the edge of the land portion at the closed position where the land portion blocks the flow of the hydraulic oil supplied to the pump port and the hydraulic oil supplied to the pump port as the spool slides. It is freely configured in the open area,
A spool hole having an inner diameter that is close to the outer circumference of the land portion and a flow path hole having an inner diameter that is larger than the outer diameter of the land portion so that the spool accommodating space receives hydraulic oil that has passed through the land portion. Have and
The flow path hole is a control valve provided with an inclined guide surface that is inclined with respect to the shaft core so that the hydraulic oil flows in a direction away from the shaft core with reference to an opening edge that receives the hydraulic oil. A reverse tilt guide in which the flow path hole is tilted in a direction opposite to the tilt guide surface so as to guide the tilt guide surface and the hydraulic oil flowing along the tilt guide surface in a direction approaching the axis. The control valve according to claim 1, which is composed of a surface. The control valve according to claim 1 or 2, wherein a notch formed in a groove shape from the opening edge toward the center of the land portion is formed in a part of the land portion in a direction along the axis. ..

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