JPH0332865Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a pilot type solenoid valve, and more specifically, it is equipped with a piston that moves in response to increases and decreases in pilot pressure, and a piston ring is provided around the outer periphery of the piston. This invention relates to a pilot type solenoid valve.

(b) Prior Art In this type of conventional solenoid valve, (a) as partially shown in FIG. 1, a main valve assembly is movably provided in a cylinder a formed within the valve body A wear ring c is provided on the outer periphery of the piston b to suppress the inclination of the main valve assembly and to prevent galling due to sliding between the outer periphery of the piston and the inner surface of the cylinder (both of which are metal). In order to reduce the amount of leakage from the surface, a piston ring d is provided at a different position on the outer periphery of the piston, and an inner ring e is inserted inside the piston ring d, or (b) a piston ring is shown in Fig. 2. There are some that use a resin lip packing f with a Y-shaped cross section so that the cross section is Y-shaped.
This is because the leakage flow rate at the outer circumference of the piston affects the stability of the operation of the solenoid valve and the stability of the valve opening/closing time, which is an important function for the solenoid valve.

However, in the above-mentioned conventional pilot type solenoid valve, the leakage flow rate from the piston ring is large;
There have been problems such as foreign matter such as dust getting caught between the inner circumference of the cylinder and the outer circumference of the piston, resulting in malfunction of the solenoid valve.

In general, with this type of solenoid valve, there are differences in piston sliding resistance, piston ring leakage flow rate, etc. depending on the shape of the wear ring or piston ring, and malfunctions are also likely to occur due to foreign objects such as dust. It affects whether or not.

(c) Purpose of the invention The present invention was created in view of the problems with the conventional pilot type solenoid valve and the above points.
The purpose is to obtain a pilot type solenoid valve that can minimize the amount of leakage from the piston ring and is less likely to malfunction due to foreign matter such as dust.

(d) Structure of the invention The invention provides a movable piston of the main valve assembly within a cylinder formed in the valve body, a pilot port communicating with the outlet port is formed in the piston, and the pilot port is opened and closed. In a pilot-type solenoid valve that moves the piston by controlling and increasing or decreasing pilot pressure acting on the piston to control communication between an inlet port and an outlet port by the main valve assembly, the axial length of the piston is The length is shortened and a single annular groove is formed on the outer periphery.
A plurality of piston rings are disposed in contact with each other in the annular groove, and a lining ring is provided on the inner peripheral side of the piston ring, and the radial thickness of the piston ring and the radial thickness of the lining ring are The sum of the thickness and thickness is made larger than the depth of the annular groove of the piston, and a groove extending in the circumferential direction is formed on the outer periphery of each piston ring, and the outer periphery is connected to the inner wall of the cylinder at a plurality of positions spaced apart in the axial direction. The main valve assembly is brought into contact with the two pistons to prevent inclination of the main valve assembly, thereby shortening the axial length of the piston that forms the pilot port.

In the above configuration, the piston is prevented from tilting even if its axial length is shortened by the plurality of piston rings, and the main valve assembly can smoothly reciprocate.
Furthermore, leakage of fluid from the outer periphery of the piston can also be effectively prevented. When the pilot port is closed, communication between the inlet port and the outlet port is blocked, and when the pilot port is opened, the inlet port and the outlet port are communicated with each other.

(e) Embodiments Examples of the present invention will be described below with reference to the drawings.

In FIG. 3, the pilot solenoid 1 of this embodiment is shown. In the figure, 2 consists of two upper and lower parts 21 and 22, including an inlet port 23, an outlet port 24, a valve seat 25, and a cylinder 2.
6 is a formed valve body, 3 is a main valve assembly movably provided within the cylinder 26 of the valve body 2, and 4 is a solenoid device attached to the upper part of the valve body.

The upper portion 21 of the valve body 2 is further formed with a pilot passageway 28 which communicates the inlet port with a pilot chamber 27 defined by the upper portion and the valve assembly 3.

The main valve assembly 3 has a piston 31 movable within the cylinder 26 and a valve body 32 mounted on the underside of the piston and engageable with the valve seat 25. Attached to the center of the piston is a valve seat body 34 in which a small pilot port 33 that allows communication between the pilot chamber 27 and the outlet port 24 is formed.

The piston 31 has a reduced thickness in the axial direction, and has one annular groove 35 formed on its outer periphery. In the annular groove 35, there are a plurality of (two in this example)
Piston rings 36a, 36 overlapped in the axial direction
b and one lining ring 37 inside the piston ring 36 are inserted. This inner ring is adapted to press the piston rings 36a, 36b radially outward from the inside. As shown in FIG. 5, the piston rings 36a and 36b are arranged so that the slits 361 do not overlap. The lining ring 37 is also arranged so that the slit 371 does not overlap with the slit of the piston ring. A V-groove 362 is formed on the outer periphery of the piston rings 36a, 36b.

The slits of the piston rings 36a and 36b may be formed at right angles to the outer surface, but as shown in FIG.
It may also be formed obliquely as shown at 61'.

The outer diameter of the piston ring is smaller than the inner diameter of the cylinder to the extent that a gap (approximately 0.3 to 0.5 mm) is formed between the outer surface of the piston and the inner surface of the cylinder so that they do not come into contact with each other. The sum of the radial thicknesses of the piston rings 36a and 36b and the radial thickness of the lining ring 37 is greater than the depth of the annular groove 35 formed in the piston. Therefore, in the assembled state, the outer circumferential surface of the piston does not come into contact with the inner circumferential surface of the cylinder, and malfunctions due to dirt or the like are not caused.

The solenoid device 4 includes a coil 41, a fixed core 42, a movable core 43, a spring 44 that presses the movable core 43 toward the main valve assembly 3, and a sealing member attached to the movable core. 46 contacts the valve seat member to close the pilot port 33.

In the pilot solenoid valve configured as described above, when the coil 41 is not energized, the movable core 43 is pressed toward the main valve assembly by the spring 44, and the seal member 46 engages with the valve seat member 34 to close the pilot port 33. . Therefore, the pressure in the pilot chamber 27 from the inlet port 23 through the pilot passage 28 becomes the same pressure as the fluid pressure in the inlet port, pushing the piston 31 downward, and the valve element 32 engages with the valve seat 25. Close the main valve.

Next, when the coil 41 is energized and the movable iron core 43 is attracted to the fixed iron core 42, the seal member 46 separates from the valve seat body and the pilot port 33 opens, so that the fluid pressure in the pilot chamber 27 is reduced to
and into the outlet port 24, reducing the pressure in the pilot chamber. Therefore, the main valve assembly 3 is pushed upward by the fluid pressure in the inlet port acting from below, causing the valve body 32 to move away from the valve seat 25 and open the main valve.

When the coil is de-energized, the movable core is pressed against the valve assembly, closing the main valve as described above.

(f) Effects The pilot type solenoid valve according to the present invention can produce the following effects.

By providing a groove-shaped labyrinth on the outer diameter surface of the piston ring, the sliding area of this piston ring is reduced, and the sliding resistance is reduced to 1/5 of that of conventional products.

With conventional products, if foreign matter such as dirt gets caught in the piston ring, the main valve assembly will not move, but with the piston ring of the present invention, even if foreign matter such as dirt gets into the V-groove labyrinth, the foreign matter will not move. When it got stuck, the labyrinth groove acted like a dust trap, and the main valve assembly was no longer locked.

By adding a labyrinth shape to the outer circumferential surface of the piston ring, it has become possible to reduce the piston ring leakage flow rate to 1/5 to 1/10 of that of conventional products.

Even if the thickness of the main valve assembly is made thinner, this piston ring can suppress the inclination of the main valve, and is a wear that prevents the metal part of the main valve assembly from touching the inner diameter surface of the sliding surface. It can also serve as a ring.

By using a plurality of piston rings, each piston ring contacts the cylinder portion independently when the piston is eccentric or tilted, improving sealing performance.

In the case of a piston that uses a combination of a wear ring and a piston ring or a wear ring and a lip packing as in conventional products, the axial length of the piston is long, but according to the present invention, the axial length of the piston is long. Since the length (in the direction of reciprocating motion) can be extremely shortened, in other words, it can be shortened to about half that of conventional products, the main valve assembly can be made more compact, and the pilot solenoid valve can be made smaller. have

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a part of a conventional pilot type solenoid valve, in which A is a sectional view, B is a perspective view of a piston ring and a lining ring, and Fig. 2 is another example of a conventional pilot type solenoid valve. FIG. 3 is a cross-sectional view of a pilot type solenoid valve according to the present invention, and FIG. 4 is a cross-sectional view of a piston ring.
The figure is an enlarged view of a part of FIG. 3, FIG. 5 is a perspective view of the piston ring and the lining ring, and FIG. 6 is a plan view of a modification of the piston ring. 1: Pilot type solenoid valve, 2: Valve body, 23:
Inlet port, 24: Outlet port, 25: Valve seat, 2
7: Pilot chamber, 3: Main valve assembly, 31: Piston, 32: Valve body.

Claims (1)

[Scope of utility model registration request] A piston of the main valve assembly is movably provided in a cylinder formed in the valve body, and a pilot port communicating with the outlet port is formed in the piston, and the pilot pressure acting on the piston is controlled by opening/closing the pilot port. In a pilot type solenoid valve that controls communication between an inlet port and an outlet port by the main valve assembly by moving the piston by increasing or decreasing the piston, the axial length of the piston is shortened and a single A plurality of piston rings are disposed in the annular groove in contact with each other, and a lining ring is provided on the inner peripheral side of the piston ring. The sum of the radial wall thickness of the inner ring is made larger than the depth of the annular groove of the piston, and a groove extending in the circumferential direction is formed on the outer periphery of each piston ring so that the outer periphery is separated in the axial direction. contacting the cylinder inner wall at multiple positions to prevent the main valve assembly from tilting;
A pilot type solenoid valve characterized by shortening the axial length of a piston that forms a pilot port.