JPH0529430Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an electromagnetic proportional pressure control valve.

(Prior Art) Conventionally, as an electromagnetic proportional pressure control valve, one described in, for example, Japanese Unexamined Patent Publication No. 182811/1983 is known.

In this conventional electromagnetic proportional pressure control valve, a valve spool that controls output hydraulic pressure is slidably installed in the valve hole, and a reaction piston is slidably inserted into the feedback hydraulic pressure chambers at both ends of this valve spool. A solenoid for pressing the valve spool is provided on the outside of both ends of the valve spool, and the plunger, reaction piston, and valve spool of the solenoid are coaxially provided, and the pressing force of the solenoid is The structure was such that the reaction force was transmitted via a piston.

To explain the operation of this conventional pressure control valve, when one solenoid is driven, the valve spool is pressed by a plunger and slides toward the other solenoid, increasing the output hydraulic pressure. Due to this increase in output hydraulic pressure, the reaction piston located on the sliding direction side of the valve spool receives feedback hydraulic pressure and slides toward the other solenoid relative to the valve spool. Retract the plunger. When the plunger's retraction is restricted by the stopper, the reaction force of the feedback hydraulic pressure applied to the reaction piston acts on the valve spool, and the valve spool moves in the direction of the driving solenoid. It is pushed back and slides relative to the reaction piston.

As a result, the valve spool is placed at a position where the pressing force of one solenoid and the feedback hydraulic pressure are balanced, and the output hydraulic pressure is controlled to be proportional to the pressing force of the solenoid, that is, the electromagnetic force. .

(Problems that the device aims to solve) However, in such conventional electromagnetic proportional pressure control valves, the valve spool, reaction piston and plunger are arranged coaxially, and the plunger is connected to the valve spool via the reaction piston. The relative sliding of the reaction piston with respect to the valve spool is indirectly performed by a stopper inside the solenoid which regulates the retraction of the plunger. This causes the following problems.

In other words, the feedback hydraulic pressure acts on the valve spool only after the reaction piston has slid until it is indirectly regulated by the stopper in the solenoid, so there is a response delay corresponding to this slide. The sliding portion between the valve spool and the reaction piston is required to have greater wear resistance than necessary, including the unnecessary sliding of the reaction piston. In addition, a stopper is required within the solenoid to restrict the sliding of the plunger, which complicates the structure accordingly.

(Means for Solving the Problems) The present invention solves the above-mentioned problems and eliminates unnecessary sliding of the reaction piston, thereby reducing the response delay of the feedback hydraulic pressure and the reaction with the valve spool. To provide an electromagnetic proportional pressure control valve that does not require excessive wear resistance between force pistons and has a simple solenoid structure.

To achieve this objective, the present invention includes a valve spool that is slidably provided in the valve hole of the valve body and controls the first and second output hydraulic pressures, and a valve spool that is coaxial with the valve spool at both ends of the valve spool. and a solenoid that presses both ends of the valve spool with a plunger disposed coaxially with the valve spool. In an electromagnetic proportional pressure control valve, the valve spool slides to a position where the feedback hydraulic pressure due to the reaction force pressing the piston is balanced, and an output hydraulic pressure proportional to the electromagnetic force of the solenoid is obtained. one side is formed into a cylindrical shape so that the two do not interfere in the axial direction, and the plunger is connected to the valve spool without going through the reaction piston, and the plunger is connected to the solenoid side with respect to the reaction piston. A stopper was installed to directly control the slide.

(Operation) The electromagnetic proportional pressure control valve of the present invention operates as described below.

When one of the two solenoids is driven, the plunger presses the valve spool without using the reaction piston, the valve spool is displaced in the pressing direction, and the output hydraulic pressure of one of the solenoids increases.

In other words, since one of the reaction piston and the plunger is formed into a cylindrical shape, even if they are arranged coaxially, they will not interfere with each other, and the pressing force of the plunger can be applied without passing through the reaction piston. It is something that can be transmitted to the valve spool.

Next, the increased output hydraulic pressure is fed back to both ends of the valve spool to press and slide the reaction piston. Then, when the slide of this reaction piston is directly regulated by the stopper,
The reaction force of the feedback hydraulic pressure that presses the reaction piston acts on the valve spool, and the valve spool is pushed back to a position where the pressing force of the solenoid and the feedback hydraulic pressure are balanced. By this,
One output hydraulic pressure is controlled to be proportional to the pressing force of the solenoid.

In the above-mentioned slide regulation of the reaction piston using the feedback hydraulic pressure, since the reaction piston is formed so as not to interfere with the plunger as described above, this regulation is performed without using the plunger, and thereby, This eliminates unnecessary sliding of the reaction piston due to the plunger sliding until it is regulated by the stopper in the solenoid.

Note that when the other solenoid is driven, the output hydraulic pressure of the other is similarly controlled to be proportional to the pressing force of this solenoid.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained.

FIG. 1 is a sectional view showing an electromagnetic proportional pressure control valve according to a first embodiment of the present invention, and this electromagnetic proportional pressure control valve includes a pump pressure circuit P and a first output circuit S1.
is connected to the second output circuit S2 and the drain circuit T. Note that both output circuits S1 and S2 are connected so that a hydraulic actuator (not shown) can be driven by these output hydraulic pressures.

In the figure, 10 indicates a valve body, in which a valve hole 11 is bored, and this valve hole 11 is connected to a first output hydraulic port 111 that communicates with the first output circuit S1 and a second output circuit S2. A second output hydraulic pressure port 112 is formed, and the pump pressure circuit P is communicated with the position between the two output hydraulic pressure ports 111 and 112, and the outer position of both the output hydraulic pressure ports 111 and 112 is connected to the second output hydraulic pressure port 112. Drain circuit T
is communicated with.

A valve spool 20 is inserted into the valve hole 11 so as to be slidable in the axial direction. This valve spool 20 is formed with a first land 21 and a second land 22, and both lands 21 and 22 are provided in both output hydraulic pressure ports 111 and 112, respectively, in an underlapping state, and the pump pressure circuit P is connected to both ports. The outputs of both output circuits S1 and S2 are controlled by restricting the drain amount of liquid supplied to the output circuits 111 and 112.

Furthermore, a first back chamber 13 and a second back chamber 14 that communicate with the drain circuit T are formed at both ends of the valve spool 20. That is, valve body 1
A first solenoid 30 and a second solenoid 40 are provided at both ends of the valve hole 11, and both ends of the valve hole 11 are closed by the casings 32, 42 of both solenoids 30, 40, thereby opening both back chambers 13, 14. It is formed. Note that 101 is a seal ring.

Both ends of the valve spool 20 are supported by springs 16, 16 via retainers 15, 15 so as to maintain a neutral position.

The first solenoid 30 and the second solenoid 4
0 presses the valve spool 20 in response to electromagnetic force, and the plungers 31, 41 of both solenoids 30, 40 are connected to the valve spool 20 via pins 51, 52. That is, the valve spool 20 has reaction piston holes 23 and 23 at both ends.
is bored coaxially with the valve spool 20.
As shown in FIG. 3, which is a cross section taken from FIG. are fitted and fixed. Further, both the plungers 31 and 41 are provided coaxially with the valve spool 20, as shown in FIG.
1 and 52, and when electromagnetic force is generated in the solenoids 30 and 40, the plungers 31 and 41 slide toward the center of the valve spool 20 and press the pins 51 and 52. , whereby the valve spool 20 is displaced.

In addition, a first reaction piston 70 is provided in the reaction piston holes 23, 23 at both ends of the valve spool 20.
A second reaction piston 80 is provided with its tip inserted so as to be slidable in the axial direction.

To explain this configuration with reference to FIG. 2, which is a partially enlarged view showing the first reaction piston 70, the first reaction piston 70 has a hollow cylindrical base 71, and a diameter that is coaxial with the base 71 and smaller than that. The pin 52 is connected to the base 71 with a predetermined stroke width h.
An escape hole 73 having a diameter of 1, h2 and capable of being loosely fitted is formed. In addition, these stroke widths h1 and h2 are
As shown in the figure, when the valve spool 20 is in a neutral state and both reaction force pistons 70 and 80 are in contact with the stopper surfaces 33 and 43 to restrict their sliding, both ports 111 of both lands 21 and 22,
The size is slightly larger than the underlap allowance for 112.

In the first reaction piston 70, the piston portion 72 is slidably inserted in the axial direction into the first feedback chamber hole 25 formed on the back side of the reaction piston hole 23. 61, and the pin 52 is inserted into the relief hole 73. Furthermore, the sliding of the first reaction piston 70 in the direction of the second solenoid 40 is caused by the first back chamber 13 of the casing 42
It is regulated by a stopper surface 43 which is an end surface facing.

The second reaction piston 80 has the same structure as the first reaction piston 70, and as shown in FIG. 1, 81 is a base, 82 is a piston portion, and 83 is an escape hole. Moreover, in the valve spool 20,
Reference numeral 26 indicates a second feedback chamber hole, 62 indicates a second feedback chamber, and 33 indicates a stopper surface of the casing 32 of the first solenoid 30.

Further, the first feedback chamber hole 25 is formed so that the hydraulic pressure of the first output hydraulic pressure port 111 can be introduced through the first feedback hole 27, and the second feedback chamber hole 26 is also formed through the second feedback hole 28. The hydraulic pressure of the second output hydraulic pressure port 112 is configured to be introduced.

Next, the operation of the first embodiment will be explained.

(a) When driving the first solenoid From the neutral state shown in Figure 1, the first solenoid 30
When driven, the tip of the plunger 31 presses the pin 51 in response to the electromagnetic force, displacing the valve spool 20 to the right in FIG. At this time,
The aperture on the drain circuit T side by both lands 21 and 22 is expanded or narrowed, respectively, and the first
The hydraulic pressure at the output hydraulic port 111 increases, while the hydraulic pressure at the second output hydraulic port 112 decreases. Further, at this time, the first reaction piston 70 is already in a state where its displacement to the right is restricted by the stopper surface 43 of the casing 42, as shown in the figure.

When the hydraulic pressure of the first output hydraulic pressure port 111 increases in this way, the increased hydraulic pressure is received by the first reaction force piston 70 which is transmitted to the first feedback chamber 61 communicated with the first feedback path 25. .
Since this first reaction piston 70 is restricted from sliding to the right as described above, the reaction force of the feedback hydraulic pressure against this first reaction piston 70 immediately moves toward the valve spool at the same time as the feedback hydraulic pressure increases. 20, the valve spool 20 is pushed back to the left in the figure, and is displaced to the left in the figure to a position where the pushing force of the first solenoid 30 and the feedback hydraulic pressure are balanced. Thereby, the first output circuit S1 is controlled to have a hydraulic pressure proportional to the pressing force (electromagnetic force) of the first solenoid 30.

Note that when the valve spool 20 is first displaced to the right in the figure, the plunger 41 is moved through the pin 52.
is pressed and moved to the right. At this time, the pin 52 strokes within the stroke width h2 (Fig. 2) within the escape hole 73, and the displacement of the valve spool 20 is regulated by the first reaction piston 70. It is something that cannot be done.

In addition, the valve spool 20 and both reaction force pistons 7
0 and 80 and both plungers 30 and 40 are coaxially arranged, force transmission is smooth and operation is stable.

(b) When the second solenoid is driven When the second solenoid 40 is driven, it operates in the opposite way to the first solenoid 30 described above, and the valve spool 20 is displaced to the left in the figure, causing the second output fluid pressure to rise. The hydraulic pressure in the circuit S2 is controlled to be proportional to the pressing force of the second solenoid 40.

The electromagnetic proportional pressure control valve of this embodiment has the following features.

Bilateral reaction force pistons 70 and 80 for applying feedback hydraulic pressure to the valve spool 20
Since the bases 71 and 81 are cylindrical, even if they are formed coaxially with the plungers 31 and 41,
Both can be wrapped without interfering with each other. By adopting this structure, the plungers 31 and 4 act as stoppers for both reaction force pistons 70 and 80.
1, thereby eliminating unnecessary sliding of both reaction force pistons 70 and 80 (that is, sliding for displacing the plunger until the sliding is restricted).

Furthermore, both reaction force pistons 70 and 80 can be moved dimensionally to the stopper surface 3 without almost sliding.
3 and 43, the sliding amount of both reaction force pistons 70 and 80 can be minimized.

As a result, there is no waste in sliding the reaction force pistons 70, 80, so that feedback responsiveness is improved. Also, valve spool 20
The amount of relative sliding between the two parts is reduced and the durability is improved. Further, the structure is simplified because no stopper is required in both solenoids 30 and 40.

Although the embodiments have been described above based on the drawings, the specific configuration is not limited to this. For example, in the embodiments, the reaction piston is formed in a cylindrical shape, but the plunger is formed in a cylindrical shape. It is also possible to prevent interference while arranging both on the same axis.

(Effects of the invention) As explained above, in the electromagnetic proportional pressure control valve of the invention, unnecessary sliding of the reaction piston is eliminated, so the response delay of the feedback hydraulic pressure is eliminated accordingly. At the same time, the effect is that less wear resistance is required between the valve spool and the reaction piston, and the structure of the solenoid is simplified as it does not require a plunger stopper. It will be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the electromagnetic proportional pressure control valve of the first embodiment of the present invention, Fig. 2 is an enlarged sectional view showing the main parts of the first embodiment, and Fig. 3 is a sectional view taken along the - line in Fig. 1. It is a diagram. 10... Valve body, 11... Valve hole, 2
0... Valve spool, 30... First solenoid, 31... Plunger, 33... Stopper surface,
40...Second solenoid, 41...Plunger,
43... Stopper surface, 70... First reaction piston, 80... Second reaction piston.

Claims (1)

[Claims for Utility Model Registration] A valve spool that is slidably provided in the valve hole of the valve body and controls the first and second output hydraulic pressures, and a valve spool that is coaxial with the valve spool at both ends of the valve spool. A solenoid that presses both ends of the valve spool with a plunger disposed coaxially with the valve spool, and the pressing force of the solenoid and the reaction piston are In the electromagnetic proportional pressure control valve, the valve spool slides to a position where the feedback hydraulic pressure due to the reaction force is balanced, and an output hydraulic pressure proportional to the electromagnetic force of the solenoid is obtained. The plunger is formed into a cylindrical shape so that they do not interfere in the axial direction, and the plunger is connected to the valve spool without going through the reaction piston, so that the plunger can be directly slid toward the solenoid side with respect to the reaction piston. An electromagnetic proportional pressure control valve characterized by having a regulating stopper.