JP7113787B2 - control valve - Google Patents

Description

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

As a control valve configured as described above, Patent Document 1 describes a configuration that suppresses the generation of flow force and stabilizes the operation of the spool.

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 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 into which hydraulic oil flows from the land portion of the spool in the sleeve that accommodates the spool is a cylindrical inner peripheral surface centered on the axial center of the spool accommodation space of the sleeve, It has a shape having a wall portion perpendicular to the axis. Therefore, when the hydraulic oil flows into the flow path from the edge of the land portion of the spool, the hydraulic oil collides with the inner peripheral wall or the wall portion, and this collision causes a flow force.

For these reasons, there is a need for a control valve that suppresses the flow force generated when hydraulic oil flows from the land portion of the spool to the flow path inside the sleeve.

The characteristic configuration of the control valve according to the present invention includes a sleeve formed with a pump port to which hydraulic oil is supplied, a spool accommodating space for accommodating a spool therein formed along the axis, and a sleeve that slides into the spool accommodating space. a spool that is movably accommodated and has a land portion and a pump-side groove smaller in diameter than the land portion and communicating with the pump port formed on the outer periphery thereof, the spool extending from the pump port to the pump-side groove ; A closed position where the land blocks the flow of the supplied hydraulic oil, and an open area where the hydraulic oil supplied from the pump port to the pump-side groove as the spool slides is delivered from the edge of the land. The spool housing space includes a spool hole having an inner diameter that is in close contact with the outer periphery of the land portion, and hydraulic oil that has passed through the edge of the land portion when the spool is operated to the open area. a passage hole having an inner diameter larger than the outer diameter of the land portion so as to receive the passage hole, the passage hole being in contact with the pump-side groove when the spool transitions from the closed position to the open area. With reference to the opening edge, which is the edge on the side where the communication is started, the inclined guide surface is inclined with respect to the axial center so that the hydraulic oil flows in a direction away from the axial center , The land portion is formed with a groove-shaped notch extending from an end on the pump side groove side in the direction along the axial center toward the center side of the land portion in the direction along the axial center, and When the spool moves from the closed position to the open area, before the hydraulic oil flows from between the edge of the land portion and the opening edge to the flow path hole, the hydraulic oil from the pump-side groove is released from the opening. The point is that it flows into the channel hole through the notch .

According to this characteristic configuration, when the hydraulic oil from the pump port is supplied to the flow passage hole from the edge of the land portion with the operation of the spool, the hydraulic oil flows along the inclined guide surface of the flow passage hole. become. Since this inclined guide surface is inclined with respect to the axis, the hydraulic oil flows in a direction away from the axis. As compared with a configuration in which a wall portion is formed in a posture orthogonal to , the flow force can be suppressed without the hydraulic oil coming into contact with the inner wall of the passage hole as if it were colliding with it.
Therefore, a control valve is constructed that suppresses the flow force when hydraulic oil flows from the land portion of the spool to the flow path inside the sleeve.

Here, it will be explained based on the measurement results that the control valve having this characteristic configuration suppresses the flow force more than the control valve having the conventional configuration. Fig. 4 shows that in the control valve of 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 stops (at the time of balance), Measurements for acquiring the pressure that the spool receives are repeated, and the measurement results are shown in the graph as IP characteristics. The IP characteristic is given by the balance formula of "solenoid thrust = spring force + spool receiving pressure", and from Fig. 4, in the control valve with this characteristic configuration, the relationship between the current supplied to 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 a control valve having a conventional configuration affected by the flow force. It can be seen that the graph in FIG. 5 has a stepped IP characteristic in which the pressure with respect to the current takes a plurality of values, and the graph in FIG. 6 has an IP characteristic in which the pressure hunts when the current increases. When the IP characteristics are not in a direct proportional relationship, it is considered that the IP characteristics do not follow the above-described balance formula but follow the formula "solenoid thrust=spring force+spool receiving pressure+flow force".
As described above, it can be understood that the flow force is suppressed in the control valve of this characteristic configuration as compared with the conventional configuration in which the influence of the flow force is large. In particular, even in hydraulic systems such as electromagnetic proportional valves that control cylinders and clutches, which require high accuracy in the relationship between the current supplied to the electromagnetic solenoid and the hydraulic pressure, the control valve of the present invention can It becomes possible to improve the operation accuracy and stability.

As a configuration in addition to the above configuration, the flow path hole is provided with respect to the inclined guide surface and the inclined guide surface so as to guide hydraulic oil flowing along the inclined guide surface in a direction approaching the axial center. You may comprise with the reverse inclination guide surface which inclines in an opposite direction.

According to this, the hydraulic fluid that has flowed from the edge of the spool along the slanted guide surface of the passage hole flows from the slanted guide surface to the reverse slanted guide surface, and flows along this reverse slanted guide surface. There is no collision, and the phenomenon that flow force is generated on this reverse inclined guide surface is also suppressed. Furthermore, the hydraulic oil that has flowed on the reverse inclined guide surface contacts the spool in a posture that is inclined with respect to the axis. to facilitate the opening of

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

According to this, the hydraulic oil can be supplied to the flow passage hole via the notch before the timing when the hydraulic oil flows from the edge of the land portion to the flow passage hole due to the operation of the spool. A sudden increase can be suppressed, and the flow force can be suppressed more satisfactorily.

FIG. 4 is a cross-sectional view of the control valve with the spool in the closed position; FIG. 4 is a cross-sectional view of the control valve with the spool in the open area; 1 is a perspective view of a spool; FIG. 4 is a graph showing the relationship between current and pressure of the control valve of the present invention; It is a graph which shows the relationship between the electric current of the conventional control valve, and pressure. It is a graph which shows the relationship between the electric current of the conventional control valve, and pressure.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below 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 slidably accommodated in the sleeve 2. As shown in FIGS.

In this control valve V, the spool 3 is held in the closed position shown in FIG. The control valve V is provided with an electromagnetic solenoid (not shown) outside the valve housing 1, and the pressing force from the plunger 5 of the electromagnetic solenoid moves the spool 3 to the open side ( 1 and 2) to apply a pilot pressure to an external controlled object via a pilot flow path 1b formed in the valve housing 1. As shown in FIG.

In particular, the electromagnetic solenoid is configured to cause the plunger 5 to protrude by an amount proportional to the supplied current value. Obtain the corresponding pilot pressure.

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

The sleeve 2 is formed with a pump port 2p to which hydraulic oil is supplied. A spool 3 is housed in a spool housing space formed along the axial center X of the sleeve 2 . The pump port 2 p communicates with the pump-side groove 3 c of the spool 3 .

The spool housing 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 channel hole S.

[Spool position]
This control valve V is maintained in the closed position shown in FIG. 1 when the electromagnetic solenoid is not driven. In this closed position, the land portion 3a enters the inner periphery of the spool hole 2a, so that hydraulic oil from the pump port 2p does not flow into the passage hole S, and the disc portion 3b of the spool 3 is positioned at the outer end of the sleeve 2. (Right end in FIGS. 1 and 2), the hydraulic fluid is not discharged from the passage hole S.

Also, when the electromagnetic solenoid is driven, the spool 3 is set in the open area shown in FIG. Since the control valve V determines the operation amount of the spool 3 in proportion to the current value supplied to the electromagnetic solenoid, the open area is not limited to the position shown in FIG. is set to any position contained 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 influence of the flow force is suppressed to set the spool 3 to an appropriate position and achieve the target The shape of the passage hole S is set so as to obtain the pilot pressure, and the notch N is provided in the land portion 3a.

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

In this control valve V, a groove-shaped notch N is formed in the land portion 3a from the left edge toward the center of the land portion 3a in FIGS. The notches N are formed at a plurality of locations (in the embodiment, two locations facing each other with the axis X interposed therebetween). It is formed.

With such a configuration, the spool 3 is actuated by the pressing force of the plunger 5 accompanying the driving of the electromagnetic solenoid, and the edge of the land portion 3a approaches the opening edge of the passage 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 passage hole S. Although the amount of hydraulic oil initially supplied is small, the hydraulic oil flows along the inclined guide surface Sa, thereby suppressing the flow force.

Next, when the edge of the land portion 3a reaches the position where it enters the flow path hole S beyond the opening edge of the flow path hole S for receiving the hydraulic oil, the operation from the edge of the land portion 3a to the flow path hole S is performed. oil will flow. When the hydraulic oil flows into the flow passage hole S in this way, part of the hydraulic oil from the pump port 2p flows along the pump-side groove 3c and further contacts the land portion 3a to move the hydraulic oil from the axial center X. Most of the hydraulic fluid flows along the inclined guide surface Sa of the flow passage hole S because it tends to flow in the direction of separation.

Since the hydraulic fluid flows smoothly and does not collide with the inclined guide surface Sa, no reaction force acts on the spool 3 via the hydraulic fluid, and the flow force is suppressed. Further, the hydraulic oil that has flowed along the inclined guide surface Sa then flows along the reverse inclined guide surface Sb, and the hydraulic oil does not collide with the reverse inclined guide surface Sb even when flowing in this way. , the flow force is suppressed.

Furthermore, the hydraulic oil that has flowed to the reverse inclined guide surface Sb contacts the spool 3 in a posture inclined about the axis X, and the component force acting on the spool 3 from the hydraulic oil due to this contact is in the direction in which the spool 3 is released. Therefore, the spool 3 can be released smoothly.

The IP characteristic of the control valve V of the present invention is that, as shown in FIG. 4, the current supplied to the electromagnetic solenoid and the pressure acting on the spool 3 have a directly proportional relationship, and the influence of the flow force is well suppressed. is understandable. On the other hand, in the conventional control valve, 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. It is understandable 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 a high degree of accuracy in the relationship between the current supplied to the electromagnetic solenoid and the hydraulic pressure, the control valve of the present invention can It is possible to improve the operating accuracy and stability of the

[Another embodiment]
The present invention may be configured as follows (components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments) in addition to the above-described embodiments.

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

(b) The control valve V shown in the embodiment was configured to discharge the hydraulic oil supplied from the land portion 3a to the flow passage hole S from the end portion of the sleeve 2, but instead of this, the control valve A configuration in which a port that communicates V with the passage hole S is formed in the sleeve 2 may be used. 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.

INDUSTRIAL APPLICABILITY The present invention can be used for a control valve that controls hydraulic fluid by operating a spool.

2 Sleeve 2a Spool hole 2p Pump port 3 Spool 3a Land portion S Channel hole Sa Inclined guide surface Sb Reverse inclined guide surface N Notch X Axis center

Claims (2)

a sleeve having a pump port to which hydraulic oil is supplied and having a spool housing space for housing the spool formed along the axis;
a spool that is slidably accommodated in the spool accommodation space and has a land portion and a pump-side groove that is smaller in diameter than the land portion and communicates with the pump port on the outer periphery of the spool;
The spool has a closed position in which the land blocks the flow of hydraulic oil supplied from the pump port to the pump-side groove , and a sliding movement of the spool to supply the hydraulic oil from the pump port to the pump- side groove . is configured to be operable with an open area for sending out hydraulic oil from the edge of the land,
The spool housing space includes a spool hole having an inner diameter that is in close contact with the outer periphery of the land, and a land portion that receives hydraulic oil that has passed through the edge of the land when the spool is operated to the open area . and a channel hole with an inner diameter larger than the outer diameter,
The flow path hole is arranged in a direction away from the axial center with reference to an opening edge, which is an edge on the side where communication with the pump-side groove is started when the spool is shifted from the closed position to the open area. provided with an inclined guide surface inclined with respect to the axis so as to flow the hydraulic oil to the
The land portion of the spool is formed with a groove-shaped notch that extends from the pump-side groove side end along the shaft center toward the center of the land portion along the shaft center. cage,
When the spool moves from the closed position to the open area, before the hydraulic fluid flows from between the edge of the land portion and the opening edge to the channel hole, the hydraulic fluid flows from the pump-side groove. A control valve that flows through the notch into the flow passage hole . The passage hole is inclined in a direction opposite to the inclined guide surface and the inclined guide surface so as to guide hydraulic oil flowing along the inclined guide surface in a direction approaching the axis. 2. The control valve of claim 1, comprising a face and a face.

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