JP2000120911A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness and stabilize a control characteristic even when operation is started with air accumulated in fluid by reliving the air to a fluid receiving part for receiving fluid on a plunger side provided between a through hole of a center post and a rod. SOLUTION: When current flows through a coil 2 and an excited condition is accomplished, a plunger 3 is attracted towad a center post 4 so as to be shifted, while a spool is also moved via a rod 5, so that a flow passage between an input port and a control port is communicated (opened) while a drain port is closed. In this case, a volume of an area R2 serving as a fluid receiving part is sufficiently larger then that of a fluid storable area R1, so that the air can be relieved to the area R2. Therefore, the plunger 3 can be prevented continuously working when air is left in the fluid storable area R1, and responsiveness in a starting time can be improved while generation of a damping phenomenon is prevented for stabilizing control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve used for various oils, pneumatic devices, and the like.

[0002]

2. Description of the Related Art A conventional solenoid valve will be described with reference to FIG. FIG. 5 is a partially cut-away schematic view of the configuration of a solenoid valve according to the prior art.

A solenoid valve 100 shown in the figure is a so-called spool valve type solenoid valve.

In FIG. 1, reference numeral 101 denotes a coil which is excited by being energized, and reference numeral 102 denotes a plunger which is attracted to a center post 103 by excitation of the coil 101.

A rod 104 is disposed in a through hole formed so as to pass through the axis of the center post 103, and has one end fixed to the plunger 102. The rod 104 reciprocates with the plunger 102. , Valve part 1
The valve (port) 05 is opened and closed.

More specifically, a spool 106 provided at the other end of the rod 104 opens and closes a port.

Reference numeral 107 denotes a spring for moving the plunger 102 away from the center post 103 via the spool 106 and the rod 104 when the coil 101 is not excited.

With the above configuration, the flow rate and pressure of the fluid are controlled by adjusting the valve opening / closing timing of the valve section 105 by the timing of energizing / de-energizing the coil 101 (for example, current control by a dither signal). Things.

[0009]

However, in the case of the above-described prior art, the following problems have occurred.

Hereinafter, the problem will be described with reference to FIG. FIG. 4 is an enlarged view of a portion C2 in FIG.

FIG. 4 shows a state when the coil 101 is not energized, that is, when the plunger 102 is most separated from the center post 103 by the urging force of the spring 107.

Here, a region formed between the plunger 102 and the center post 103 (the fluid storable region R)
When the plunger 102 is sucked by the center post 103, the fluid in the area 3 (represented by a hatched area in the drawing) is pushed out by the plunger 102 and passes through a groove 103 a formed on the outer peripheral wall of the center post 103. Valve 10
Spilled out of zero.

By the way, when the coil 101 is shifted from the energized state to the non-energized state, in order to separate the plunger 102 from the center post 103 satisfactorily, a non-magnetic shim 106 is connected between the plunger 102 and the center post 103. It is interposed between them.

The shim 106 is used for the plunger 1 described above.
A configuration is adopted in which a part of the through hole formed in 02 is fitted with a large diameter.

Here, the length of the large-diameter portion of the through-hole is set longer than the length in which the shim 106 is fitted, and a region in which the fluid can be stored (a space region R4 (XX in the figure)). Region)).

A groove, a notch or the like is provided in the shim 106 to secure a fluid flow path.

Therefore, when the plunger 102 is sucked by the center post 103, a part of the fluid in the fluid storable area R3 can escape to the space area R4.

However, in the initial operation state,
Air stays in the above-mentioned fluid storable region R3, and the air cannot be completely removed unless the plunger 102 reciprocates a plurality of times.

Therefore, in the initial state of operation, although a part of the air escapes into the groove 103a or the space region R4, a part of the air cannot escape and the plunger remains in the fluid storable region R3. Since the 102 continued to operate, a damping phenomenon (chattering) occurred, and stable control (oil pressure control) could not be obtained.

In addition, since the air cannot escape, the responsiveness is affected, resulting in a response delay.

In particular, the state in which air remains remains for a while, and it may take a long time for the control to stabilize.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a solenoid valve which improves responsiveness and stabilizes control characteristics. It is in.

[0023]

In order to achieve the above object, according to the present invention, a plunger which is attracted to a center post when an exciting means is in an excited state, and a plunger which is attracted to a center post when the exciting means is in a non-excited state. Urging means for urging in a direction to separate from the center post, and arranged reciprocally in a through hole provided in the center post,
A solenoid valve having one end fixed to the plunger and a valve opening / closing means for opening / closing a valve at the other end; a solenoid valve including a through hole provided in the center post and a rod. A fluid receiving portion for receiving the fluid on the plunger side is provided, and the volume of the fluid receiving portion is at least the same volume as the fluid storable volume between the plunger and the center post when the plunger is most separated from the center post. It is characterized by having.

Therefore, even when the operation is started in a state where the air stays in the fluid between the plunger and the center post because the fluid receiving portion is provided, the air can escape into the fluid receiving portion. it can.

[0025]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

First, the overall configuration of the solenoid valve 1 will be described with reference to FIG.

FIG. 1 is a schematic structural view of a solenoid valve according to an embodiment of the present invention. FIG. 1 (a) is a partially cutaway sectional view of the entire solenoid valve, and FIG. Plan view of the center post (Fig. 1
(A) is a plan view seen from the middle right to the left), and FIG.
FIG. 1C is a cross-sectional view taken along a line AB in FIG.

The center post in FIG. 1A shows an AC cross section in FIG. 1B.

FIG. 1A is a cross-sectional view in which a broken portion is changed in some places for simplicity of explanation.
The breaks are changed at the 1, D2, D3 and D4 portions.

The solenoid valve 1 is roughly divided into a solenoid portion 1a and a valve portion 1b.

In the solenoid section 1a, a coil 2 as an exciting means is disposed in a case 12 in a state of being integrally formed in a mold.

When the coil 2 is energized through the connector 10 (10a is a terminal), a magnetic path is formed to pass through the plunger 3, the center post 4 and the plate 9, which are magnetic substances (excited state). The plunger 3 movably provided is sucked by the fixed center post 4.

The center post 4 is formed with a through hole 41 so as to pass through its axis.
A rod 5 is reciprocally arranged in the housing 1.

One end of the rod 5 is connected to the plunger 3.
(In the illustrated example, the rod 5 is inserted and fixed in a hole provided in the plunger 3), and the rod 5 reciprocates with the movement of the plunger 3.

In order to improve the separation performance between the plunger 3 and the center post 4, a non-magnetic shim 8 is provided between them.

The shim 8 is fitted with the shim 8 with a part of the above-described through hole 41 having a large diameter 41a (see FIG. 1C).

Further, a bearing 11 is provided on the side of the center post 4 opposite to the side on which the shim 8 is fitted to position the rod 5.

On the other hand, the valve portion 1b has an input port P1, a control port P2, and a drain port P as ports for fluid communication with the outside of the solenoid valve 1.
3 and P4 are provided.

The other end (valve portion 1b) of the rod 5 is provided with a spool 6 which constitutes a valve opening / closing means.
Is fixed, and reciprocates as the rod 5 reciprocates.

That is, when the coil 2 is energized to be excited, the plunger 3 is attracted by the center post 4 and moves to the left in FIG. 1A, and the spool 6 also moves to the left via the rod 5. When the flow path between the input port P1 and the control port P2 is communicated (opened) and the drain port P3 is closed, and the coil 2 is de-energized to be in a non-excited state, the spring 7 serving as urging means is turned on.
The spool 6 moves to the right side in the figure by the urging force of (1), closing the input port P1, and making the flow path between the control port P2 and the drain port P3 communicate (open).

In the non-excited state, the plunger 3 is separated from the center post 4 via the rod 5 as the spool 6 moves rightward in the drawing by the urging force of the spring 7.

In the solenoid valve 1 configured as described above, the timing of energizing / de-energizing the coil 2 is controlled (for example, current control by a dither signal) to control the opening / closing timing of each port. ,
It is for controlling the flow rate and pressure of the fluid (hydraulic control for outputting to the control port P2).

In the drawing, O1 to O5 are O-rings for preventing leakage of fluid in each part.

The portion indicated by S in the drawing indicates a stepped portion, that is, a stepped portion for changing the diameter of the inner wall corresponding to the difference in the diameter of the land 6a and the land 6b constituting the spool 6. Is provided.

Hereinafter, the reason why the diameters of the lands 6a and 6b are different will be briefly described with reference to FIG.

FIG. 2 is a schematic diagram schematically showing the relationship between the spool and each port.

When a certain current is applied, the solenoid thrust (F
_{For K} ), the balance formula F _K = P _S (hydraulic pressure) + F _S (spring force) holds.

At this time, the spool 6 is connected to the P port (the input port P in FIG. 1) in order to secure the secondary pressure P ₂ (the pressure of the A port (corresponding to the control port P2 in FIG. 1)).
(Equivalent to 1) to open and balance.

The spool 6 is slightly vibrating because the solenoid is operated by dither control.

The axial force (hydraulic pressure) acting on the spool 6 is determined by the difference between the diameter (A) of the land 6a and the diameter (B) of the land 6b, and is expressed by the following equation. .

P _S = [(B ² −A ² ) × π / 4] × P ₂
For the above reasons, the diameters of the lands 6a and lands 6b constituting the spool 6 are different (if the diameters are equal, P _s = 0 according to the above equation).

Next, a description will be given, with reference to FIG. 3, of a feature of the present embodiment, such as a configuration for preventing an adverse effect due to residual air in an initial operation state.

FIG. 3 is an enlarged view of a portion C1 in FIG.

FIG. 3 shows a state when the coil 2 is not energized, that is, when the plunger 3 is in the state most separated from the center post 4 by the urging force of the spring 7.

Here, the plunger 3 and the center post 4
When the plunger 3 is sucked by the center post 4, the fluid in the region formed between the center post 4 and the center post 4 is pushed out by the plunger 3. Through the groove 42 (see FIGS. 1B and 1C) formed on the outer peripheral wall of the drain port P3.
4 and flows out of the solenoid valve 1 (see FIG. 1).
(A) It flows out in the middle arrow Y direction).

Here, in the present embodiment, a region R2 (XX region in the figure) as a fluid receiving portion for receiving the fluid in the fluid storable region R1 is formed to function as an air reservoir. I have.

The volume of the region R2 can be set by extending a large diameter portion 41a formed in a part of the through hole 41 to fit the shim 8 in the axial direction.
In the present embodiment, the volume of the region R2 is set to be approximately twice the volume of the fluid storable region R1.

A groove, a notch or the like is provided in the shim 8 to secure a fluid flow path.

With the above-described structure, the operation is started in a state where the air stays in the fluid storable region R1 and the plunger 3 cannot escape from the groove 42 when the plunger 3 is sucked into the center post 4. The air can escape into the region R2 because the volume of the region R2 is sufficiently larger than the volume of the fluid storable region R1, and the air remains in the fluid storable region R1. It is possible to prevent the plunger 3 from continuing to operate, improve the responsiveness at the time of startup, prevent the occurrence of a damping phenomenon (chattering), and obtain stable control (hydraulic control).

In the above description, the case where the volume of the region R2 is set to be approximately twice the volume of the fluid storable region R1 has been described. It suffices if it is the same as the volume of R1.

However, actually, regarding the setting of the volume of the region R2, the length and diameter of the center post 4,
By considering the diameter of the rod 5 and optimizing the setting of the volume of the fluid receiving portion (the volume of the region R2) in accordance with the state of the air in the fluid, the air can be efficiently released.

As an example, as described above, as a result of setting the volume to approximately twice the volume of the fluid storable region R1, the result is as follows.
A sufficient effect was obtained.

[0063]

As described above, according to the present invention, even when the operation is started in a state where air stays in the fluid between the plunger and the center post, the plunger remains in the state where the air stays. Can be prevented from continuing to operate, the responsiveness can be improved, and the control characteristics can be stabilized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a solenoid valve according to an embodiment of the present invention.

FIG. 2 is a schematic diagram schematically showing a relationship between a spool and each port.

FIG. 3 is an enlarged view of a main part of the solenoid valve according to the embodiment of the present invention.

FIG. 4 is an enlarged view of a main part of a solenoid valve according to the related art.

FIG. 5 is a partial cross-sectional view schematically illustrating a configuration of a solenoid valve according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 solenoid valve 2 coil 3 plunger 4 center post 41 through hole 41a large diameter 42 groove 5 rod 6 spool 6a, 6b land 7 spring 8 shim 9 plate 10 connector 10a terminal 11 bearing 12 case P1 input port P2 control port P3, P4 Drain port O1, O2, O3, O4, O5 O-ring S Step

Claims (1)

[Claims] 1. A plunger which is attracted to a center post when an exciting means is in an excited state; an urging means which urges the plunger in a direction for separating the plunger from the center post when the exciting means is in a non-excited state; And a rod having one end fixed to the plunger and provided with valve opening and closing means for opening and closing the valve at the other end. In the above, a fluid receiving portion for receiving the fluid on the plunger side is provided between the through hole provided in the center post and the rod, and the volume of the fluid receiving portion is such that when the plunger is most separated from the center post, A solenoid valve having at least the same volume as a fluid storable volume between a plunger and a center post.