JP4077190B2 - Two-stage solenoid valve for water pressure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Conventionally, oil such as mineral oil has been used as a working fluid (pressure medium) for operating a drive system. However, in recent years, demands and regulations for system safety and environmental protection tend to be stricter. In order to avoid dangers such as environmental pollution and fire due to oil leakage, development of a hydraulic system using water as a working fluid is desired.
[0002]
Since water has significantly different physical properties from mineral oil, it contains many problems to be solved regarding the performance and durability of the equipment, but with the latest material technology, processing technology, design, etc., hydraulic pumps, hydraulic actuators, It is considered that it can be applied to water pressure equipment such as a water pressure servo valve, and efforts to put the water pressure system into practical use are being actively promoted.
[0003]
The present invention relates to a two-stage hydraulic solenoid valve that can use water as a working fluid.
[0004]
[Prior art]
As a solenoid valve that uses oil as a working fluid, a solenoid valve having a configuration as shown in FIG. 7 in which a balance piston is arranged to reduce power is known. Such a structure is a two-way hydraulic solenoid valve having a P port connected to the supply side route and an A port connected to the supply side route, and has an advantage that it can be operated at a high speed and has very little internal leakage. Widely used in hydraulic system control.
[0005]
By the way, when an electromagnetic valve having such a structure is applied to a hydraulic system using water as a working fluid, if the supply pressure exceeds a certain value (about 2 MPa) despite the valve body being in the closed position, the A port There was an inevitable problem that a considerable amount of water leaked out.
[0006]
This is probably because the balance piston does not have an O-ring as a seal member, and water has a lower viscosity than oil. In addition to avoidance, it is essential to consider problems such as high-speed operation, rust, lubrication, and cavitation erosion, and it is impossible to use conventional solenoid valves for water pressure. there were.
[0007]
In this regard, although an attempt has been made to apply a structure as shown in FIG. 8 using a poppet type valve in place of the balance piston, in this case, in order to maintain the off state (closed state) of the valve. Requires a strong spring and at the same time a high-power solenoid is essential, and there is still room for improvement.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to propose a two-stage water pressure electromagnetic valve that is free from internal leakage even when water is used as a working fluid, and that enables high-speed operation and power saving.
[0009]
[Means for Solving the Problems]
The present invention is an electromagnetic valve that controls opening and closing of a path connected to an actuator by operating a valve body arranged in a body in a drive system composed of a combination of a solenoid, a core and a yoke,
A first space region in the body joins the working fluid supply path and the working fluid feed path connected to the actuator, and a partition wall having a passage connected to the first space region and the working fluid supply path. Two space areas are provided,
Connecting the working fluid feed path and the second space region via a bypass path;
In the first space region, a valve seat and a sleeve, which are held in a liquid-tight state by a sealing member along the inner wall surface, are disposed and elastically supported via a spring, and a working fluid supply path cooperates with the valve seat. the main valve to maintain the closed state Te arranged,
In the second space region, the passage of the partition wall is elastically supported via a spring and is maintained in a closed state, but as a working fluid in the gap between the main valve body and the sleeve by controlling the pilot flow rate in the passage. An auxiliary valve is provided that causes a flow in the water of the main valve, breaks the pressure balance at the front and rear ends of the main valve, and lifts the main valve from the valve seat to open the working fluid supply path. This is a two-stage water pressure solenoid valve.
[0010]
In the two-stage water pressure electromagnetic valve configured as described above, the main valve can be a poppet type valve element, and the auxiliary valve can be a ball type or a poppet type valve element similar to the main valve.
[0011]
Further, the main valve having a diameter connecting the working fluid supply path and the partition wall passage with a gap formed between the main valve body and the first space region wall surface is particularly advantageously adapted. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 shows the structure of a two-stage hydraulic solenoid valve according to the present invention.
[0013]
In the figure, 1 is the body of the solenoid valve. Body 1 and the first spatial region K ₁ for combining the hydraulic fluid delivery path A leading to the working fluid supply path P and the actuator therein, passages c leading to the first spatial region and working fluid supply path P partition wall (also serving as a valve seat) second spatial region via the W K ₂ is provided with.
[0014]
In the first space region K ₁ , a valve seat 2 and a sleeve 3 that are held in a liquid-tight state by a sealing member such as an O-ring are disposed along the inner wall surface, and are elastically supported via the spring S _{1 and} are actuated. A poppet-type main valve 4 that maintains the feeding path A in a closed state in cooperation with the valve seat 2 is disposed. A gap r of about 30 μm is formed between the main valve 4 and the sleeve 3, and the pressure receiving areas of the front end (lower side in the figure) and the rear end (upper side in the figure) are almost equal or slightly at the rear end. It has become big.
[0015]
Further, the second spatial region K _2, the rear end region a second sleeve 5 and the sleeve 5 made of non-magnetic material which projects from the spatial domain K ₂ via a spring S ₂ elastically supported by the partition wall An auxiliary valve 6 is disposed to keep the W passage c closed.
[0016]
A valve body (pilot valve) 6a shown in the example of the ball type for the auxiliary valve 6 for controlling the pilot flow rate in the passage c, the elastic force of the spring S ₂ in the 5 sleeve is molded integrally with the valve body 6a the slidable its rear region by anti consist second spatial region K plunger 6b which projects from ₂ together with the sleeve 5, the said auxiliary valve 6 so that pressure acting around its is always constant Is provided with a through hole 6c.
[0017]
Further, 7 is a spacer made of a magnetic material surrounding the sleeve 5 projecting from the second spatial region K _2, the end of the spacer 7 ring 7a made of a nonmagnetic material is attached.
[0018]
8 is a fixing ring that firmly holds the sleeve 5 together with the spacer 7 to the body 1, and 9 is a core disposed on the ring 7a with a gap h at the end face of the plunger 6b. yokes for forming a tract, 11 wound solenoid to surround the gap h formed at an end surface of the core 9 and the plunger 6b, and 12 a second spatial region K ₂ and the working fluid feed path a The working fluid passing through the auxiliary valve 6 is sent to the working fluid feeding route A through the bypass route 12.
[0019]
The core 9, the yoke 10 and the solenoid 11 constitute a drive system for the solenoid valve. By this, the plunger 6b is appropriately sucked together with the valve body 6a toward the core 9 to open and close the passage c to control the pilot flow rate. To do.
[0020]
When the auxiliary valve 6 is operated in the drive system, a water flow as indicated by an arrow in the figure occurs in the gap r between the main valve 4 and the sleeve 3, and the pressure of the water drops when passing through the gap r. Then, the pressure at the rear end of the main valve 4 becomes lower than the pressure at the front end. As a result, the pressure balance between the front end and the rear end of the main valve 4 is lost, and the main valve 4 is lifted from the valve seat 2 to be in an open state. As a result, the water flows to the working fluid feed path A connected to the actuator.
[0021]
In the electromagnetic valve configured as described above, the auxiliary valve 6 that controls the pilot flow rate can be operated at high speed with low power using a small solenoid, and the first space region in which the main valve 4 is disposed. K ₁ is the leakage is no at that site since the main valve 4 unless actuate the auxiliary valve 6 is reliably meet the valve seat 2.
[0022]
FIG. 2 shows a water pressure circuit using the solenoid valve having the structure shown in FIG. 1, and a pulse width modulation system (using a water pressure circuit for applying an overexcitation voltage and a demagnetization voltage to the solenoid 10 of the drive system). The flow rate was controlled by an electric circuit dedicated to high-speed driving (PWM), and the operation delay characteristics of the auxiliary valve 6 were investigated.
[0023]
The result is shown in FIG. This investigation pays attention to the fact that a large impact is generated at the moment when the valve body 6a or the plunger 6b of the auxiliary valve 6 contacts the partition wall W or the core 9, and the impact is measured using an impact sensor. As is apparent from FIG. 3, the time of about 1 ms from when the on / off input signal is generated to when the impact signal is generated is the open / close operation delay time of the valve (auxiliary valve 6), and can be operated at high speed. I understand.
[0024]
FIG. 4 is a graph showing the relationship between the duty (the ratio of the ON time in the input signal to the total time (ON / OFF time)) and the pilot flow rate.
[0025]
From FIG. 4, the pilot flow rate in the auxiliary valve 6 generally tends to increase linearly with the duty.
[0026]
FIG. 5 shows the result of investigating the relationship between the duty and the main flow rate (flow rate of the main valve 4). The solenoid valve of the present invention is a two-stage solenoid valve, and the main flow rate is larger than the pilot flow rate, but the characteristics of the pilot flow rate are reflected as they are, and it can be seen that they have the same tendency.
[0027]
6 shows the flow rate fluctuation of the main valve 4 when the load pressure is applied in the range of 0 to 6 MPa by adjusting the opening degree of the valve arranged in the working fluid feed path A in the hydraulic circuit shown in FIG. It is the shown graph. In general, the larger the load pressure is, the smaller the flow rate is. However, when the load pressure is 1 MPa, the duty pressure is 70 or less, which is higher than that when there is no load. This is because the load pressure acts on the tip (lower part) of the main valve 4. It is assumed that the main valve 4 is more open.
[0028]
The hydraulic solenoid valve according to the present invention can be composed of all stainless steel components. In particular, the main valve 4 and its valve seat 2 and the valve body 6a of the auxiliary valve 6 and its valve seat are heat treated. It is preferable to use stainless steel, but any steel material such as carbon steel can be used as long as it is subjected to surface treatment such as plating, and is not limited to stainless steel.
[0029]
The flow rate of the main valve 4 can be basically controlled by controlling the pilot flow rate of the auxiliary valve 6, but the clearance (clearance) r formed between the body of the main valve 4 and the sleeve 3 is the pilot flow rate. The control range of the main valve 4 is significantly changed in accordance with the size of the solenoid valve and the working fluid supply conditions, and is used in the body of the main valve 4 instead of the gap r. The passage may be provided.
[0030]
【The invention's effect】
According to the present invention, even when water is used as the working fluid, there is no internal leakage at all, and it can be operated at a high speed, so that it is easy to construct a hydraulic system.
[0031]
In addition, according to the present invention, unlike an electrically driven or hydraulically driven solenoid valve, it is excellent in fire resistance and heat resistance, and it is possible to effectively avoid environmental pollution that is particularly concerned in hydraulically driven types. It can be widely applied not only to the food processing industry, disaster prevention industry, and semiconductor industry, but also to industries that handle agricultural machinery and underwater machinery.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a two-stage hydraulic solenoid valve according to the present invention.
FIG. 2 is a diagram schematically showing a hydraulic circuit to which an electromagnetic valve according to the present invention is applied.
FIG. 3 is a graph showing a result of investigating an operation delay characteristic.
FIG. 4 is a graph showing the relationship between flow rate and duty.
FIG. 5 is a graph showing the relationship between flow rate and duty.
FIG. 6 is a graph showing the relationship between flow rate and duty.
FIG. 7 is a diagram showing a configuration of a conventional electromagnetic valve.
FIG. 8 is a diagram showing a configuration of a poppet type solenoid valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electromagnetic valve body 2 Valve seat 3 Sleeve 4 Main valve 5 Sleeve 6 Auxiliary valve 6a Valve body 6b Plunger 7 Spacer 7a Ring 8 Fixing ring 9 Core
10 York
11 Solenoid
12 Bypass path
13 Balance piston
14 Spring
15 Solenoid
16 core
17 Pivot valve
18 Spring
19 Solenoid
20 Core P Working fluid supply path A Working fluid feed path K ₁ First space region K ₂ Second space region W Partition wall c Passage s ₁ Spring s ₂ Spring r Clearance h Clearance

Claims (2)

An electromagnetic valve that controls the opening and closing of a path connected to an actuator by operating a valve body arranged in the body in a drive system comprising a combination of a solenoid, a core and a yoke,
A first space region that joins the working fluid supply path and the working fluid feed path connected to the actuator in the body, and a partition wall that includes a passage connected to the first space region and the working fluid supply path. Two space areas are provided,
Connecting the working fluid feed path and the second space region via a bypass path;
In the first space region, a valve seat and a sleeve, which are held in a liquid-tight state by a sealing member along the inner wall surface thereof, are arranged and elastically supported via a spring to cooperate with the valve seat. A main valve to keep it closed
The second spatial region, but to keep the passage closed state of the elastic supported partition wall via a spring, as a working fluid in the gap between the barrel and the sleeve of the main valve by controlling the pilot flow rate in the passage The auxiliary valve is arranged to cause a flow in the water of the main valve, disengage the pressure balance at the front and rear ends of the main valve, and lift the main valve from the valve seat to open the working fluid supply path. Two-stage water pressure solenoid valve.   The main valve has an outer diameter that forms a gap between the body portion of the main valve and the wall surface of the first space region to connect the working fluid supply path and the passage of the partition wall. Two-stage solenoid valve for water pressure.

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