JP7535802B2 - Pilot Operated Solenoid Valve - Google Patents

Description

The present invention relates to a pilot-operated solenoid valve.

Conventionally, pilot-type solenoid valves have been known in which a pilot valve element is driven to open and close by an electromagnetic actuator, and the main valve element opens and closes in response to the pilot valve element, thereby opening and closing the fluid flow path.

Patent document 1 discloses a pilot-type solenoid valve in which, when current is applied to a coil, a plunger is attracted to an attractor and adhered to the attractor, which in turn moves the pilot valve body in the valve opening direction, and the back pressure chamber is depressurized by discharging the fluid in the back pressure chamber through a leakage passage, causing the main valve body to be lifted by the biasing force of a valve spring and opening the valve.

Japanese Patent Application Publication No. 02-283985

In the solenoid valve of Patent Document 1, a circular hole is machined into the valve body, so that a sliding surface against which the main valve element slides is connected to the valve chamber. Meanwhile, piping that allows fluid to flow in and out of the valve chamber is brazed to the valve body so that it intersects with the axis of the sliding surface. For this reason, a machined hole for inserting the piping is formed in the valve body so that it communicates with the valve chamber, but in order to prevent mutual interference, the sliding surface is formed a certain distance away from the machined hole for inserting the piping.

As with this conventional technology, if the sliding surface of the main valve body is separated from the machined hole for inserting the piping, and the distance between the valve seat on which the main valve body sits and the sliding surface becomes long, the main valve body becomes more likely to wobble due to the balance of forces, which may cause the valve body to tilt. If the valve body tilts significantly, the sealing performance between the main valve body and the valve seat deteriorates, resulting in fluid leakage.

Another issue is that the sliding surface of the main valve body is separated from the drilled hole for inserting the piping, which increases the overall length of the valve body and the pilot solenoid valve.

The present invention was made in consideration of the above problems, and aims to provide a pilot-operated solenoid valve that can ensure sealing when the valve is closed while keeping the overall length small.

The pilot type solenoid valve according to the present invention comprises:
a valve body including a valve chamber communicating with an inlet opening and an outlet opening, and an insertion opening communicating with the valve chamber;
a pilot valve body that is movable relative to the valve body;
a main valve body that is movable so as to seat on or separate from a valve seat in the valve chamber;
a sleeve inserted into the insertion opening;
The main valve body slides along the inner circumferential surface of the sleeve ,
A plunger that holds the pilot valve body slides along the inner circumferential surface of the sleeve,
A ring-shaped stopper against which an upper portion of the main valve body abuts is attached to the inner periphery of the sleeve by crimping a part of the sleeve.
A pilot operated solenoid valve.
The pilot type solenoid valve according to the present invention comprises:
a valve body including a valve chamber communicating with an inlet opening and an outlet opening, and an insertion opening communicating with the valve chamber;
a pilot valve body that is movable relative to the valve body;
a main valve body that is movable so as to seat on or separate from a valve seat in the valve chamber;
a sleeve inserted into the insertion opening;
The main valve body slides along the inner circumferential surface of the sleeve,
a guide pipe on which a plunger holding the pilot valve body slides and an annular stopper against which an upper portion of the main valve body abuts is sandwiched between the guide pipe and the sleeve;
It is characterized by:

The present invention provides a pilot-operated solenoid valve that can ensure sealing when the valve is closed while keeping the overall length small.

FIG. 1 is a vertical cross-sectional view showing a pilot type solenoid valve according to a first embodiment. FIG. 2 is a vertical sectional view showing a pilot type solenoid valve according to the second embodiment. FIG. 3 is a vertical sectional view showing a pilot type solenoid valve according to a third embodiment.

Below, an embodiment of the pilot-operated solenoid valve according to the present invention will be described with reference to the drawings. In this specification, "upper" refers to the suction element side, and "lower" refers to the main valve body side relative to the suction element.

[First embodiment]
FIG. 1 is a vertical cross-sectional view showing a pilot type solenoid valve 1 according to a first embodiment, and shows the valve in a closed state.
The pilot type solenoid valve 1 shown in the figure is used in, for example, a refrigeration cycle of a chiller or the like, and is used in combination with an electromagnetic actuator 20 .

The pilot-operated solenoid valve 1 comprises a valve body 10 made of metal (e.g., brass) and a main valve body 15 slidably inserted into the valve body 10. The axis of the pilot-operated solenoid valve 1 is designated as L.

The valve body 10 has a valve chamber VC inside, and has a bottomed cylindrical shape with a side wall 12 and a bottom wall 13 connected to each other. A thin cylindrical section 13a is formed in the center of the bottom wall 13 and protrudes upward, and the inside of the thin cylindrical section 13a forms an outlet opening 13b that penetrates the bottom wall 13 along the axis L. A valve seat 14 is formed at the upper end of the outlet opening 13b. An outflow pipe OT is connected and fixed to the bottom wall 13 by brazing or the like so as to communicate with the outlet opening 13b.

The radially inner side of the side wall 12 is an insertion opening 12p that connects to the valve chamber VC. The insertion opening 12p is preferably cylindrical. An inlet opening 12a is formed in the side wall 12 of the valve body 10, and an inlet pipe IT is connected and fixed by brazing or the like so as to communicate with the inlet opening 12a. The axis of the inlet pipe IT is O.

The side wall 12 has a step 12b between the inlet opening 12a and the valve chamber VC against which the inlet pipe IT abuts, and the inlet opening 12a and the valve chamber VC are connected via a circular opening 12c formed in the step 12b.

The cylindrical main valve body 15 with a bottom is made up of a tubular portion 15a and a bottom portion 15b connected to the lower end of the tubular portion 15a. The outer peripheral surface of the tubular portion 15a forms a sliding surface 15c of the same diameter, and the outer periphery of the lower end of the bottom portion 15b forms a tapered surface 15d that narrows in diameter downward. In the closed valve state of Figure 1, the tapered surface 15d of the main valve body 15 sits on the valve seat 14, closing the outlet opening 13b.

The bottom portion 15b has a pilot valve port 15e that penetrates along the axis L. The pilot valve port 15e may be a stepped hole whose lower portion is enlarged in diameter, and its upper end forms the pilot valve seat 15f.

A metal (e.g., stainless steel) guide pipe 32 is inserted into the inner circumference (insertion opening 12p) of the side wall 12 of the valve body 10. The guide pipe 32 is preferably fitted into the insertion opening 12p. The lower end of the guide pipe 32 or a part of the lower end side of the guide pipe 32 is inserted to a position below the upper end of the circular opening 12c (i.e., a position overlapping with the inlet opening 12a when viewed in the direction of the axis O of the inlet opening 12a). The guide pipe 32 is fixed to the valve body 10 by brazing the inner peripheral surface of the guide pipe 32 to the inner peripheral surface of the side wall 12. In this embodiment, the guide pipe 32 also serves as a sleeve.

A ring-shaped stopper 33 is attached to the inner circumference of the guide pipe 32 at a position spaced a predetermined distance from the bottom end. The stopper 33 has a circumferential groove 33a on the outer circumference. The guide pipe 32 is crimped from the outer circumference to correspond to the circumferential groove 33a, causing plastic deformation, and the stopper 33 can be attached to the guide pipe 32.

In the valve chamber VC, a valve-opening spring 18 made of a coil spring is disposed between the bottom 15b of the main valve body 15 and the bottom wall 13 of the valve body 10, and biases the main valve body 15 upward relative to the valve body 10.

In FIG. 1, the electromagnetic actuator 20 includes a coil unit (also called a coil) 22 for energizing excitation, a housing 21 arranged to cover the outer periphery of the coil unit 22, a bottomed cylindrical or columnar attractor 25 arranged on the upper inner periphery of the coil unit 22 and fixed to the housing 21 by a bolt 28, and a plunger 30 arranged opposite the attractor 25 along the axis L. Inside the housing 21, the periphery of the coil unit 22 is covered with a resin mold.

The plunger 30 is made up of a large diameter section 34 that is slidably fitted to the inner circumference of the guide pipe 32, and a small diameter section 35. The small diameter section 35 passes through the stopper 33, and its lower end is inserted into the cylindrical section 15a of the main valve body 15.

A retaining hole 35a is provided at the lower end of the small diameter portion 35. A pilot valve body 31 made of a ball is housed in this retaining hole 35a. The pilot valve body 31 is fixed by crimping a rivet portion 35b that protrudes cylindrically from the lower end of the plunger 30 radially inward with a portion of its lower surface exposed.

When the plunger 30 moves downward, it moves the pilot valve body 31 in the valve closing direction, and when the plunger 30 moves upward, it moves the pilot valve body 31 in the valve opening direction. A back pressure chamber BC is formed between the small diameter portion 35 of the plunger 30 and the main valve body 15.

The upper part of the plunger 30 is formed with a vertical hole (spring chamber) 30a and a horizontal hole (pressure equalizing hole) 30b into which the valve-closing spring 26, which is a coil spring, is inserted and locked. The valve-closing spring 26 biases the plunger 30 in a direction away from the suction element 25.

The upper end of the guide pipe 32 is disposed in the annular gap between the coil unit 22 and the attractor 25, and the plunger 30 can slide along its inner circumference. The upper end 32a of the guide pipe 32 is fixed to the stepped outer periphery of the attractor 25 by TIG welding or the like.

(Operation of pilot operated solenoid valve)
The operation of the pilot type solenoid valve 1 will now be described.
In the closed valve state, the plunger 30 is biased downward by the valve closing spring 26, the pilot valve body 31 is seated on the pilot valve seat 15f, blocking the pilot valve port 15e, and the tapered surface 15d of the main valve body 15 is seated on the valve seat 14.

In the closed valve state, the high-pressure fluid introduced from the inlet pipe IT through the inlet opening 12a into the valve chamber VC passes between the outer circumferential surface of the main valve body 15 and the inner circumferential surface of the guide pipe 32 (between the sliding surfaces) and is introduced into the back pressure chamber BC. However, a communication hole may be provided in the main valve body 15 so that the valve chamber VC and the back pressure chamber BC are in communication with each other.

Referring to FIG. 1, the fluid introduced into the back pressure chamber BC is also guided to the gap space CS formed between the lower end surface of the suction element 25 and the plunger 30 through the gap between the outer peripheral surface of the plunger 30 and the inner peripheral surface of the guide pipe 32 (between the sliding surfaces), the horizontal hole 30b, and the vertical hole 30a.

When the coil unit 22 is energized from a power source (not shown) in the pilot solenoid valve 1 in the closed state, the attractor 25 is excited and the plunger 30 is magnetically attracted, causing the pilot valve body 31 to rise in the valve opening direction. Because the internal pressures of the back pressure chamber BC and the clearance space CS are equal, the operation of the plunger 30 is not impeded.

When the pilot valve orifice 15e opens due to the rise of the pilot valve body 31, the fluid in the back pressure chamber BC flows out through the pilot valve orifice 15e to the low pressure side outlet opening 13b. This causes the pressure in the back pressure chamber BC to decrease, and the main valve body 15 rises while the sliding surface 15c slides against the inner surface of the guide pipe 32 due to the pressure difference between the valve chamber VC and the back pressure chamber BC and the biasing force of the valve opening spring 18.

When the main valve body 15 rises, the tapered surface 15d moves away from the valve seat 14, and the fluid that has flowed into the valve chamber VC from the inlet pipe IT flows out into the outlet pipe OT via the valve seat 14 and the outlet opening 13b. The main valve body 15 is locked in the open position by its upper end abutting against the lower surface of the stopper 33 of the guide pipe 32.

In contrast, when the power supply to the coil unit 22 from the power source (not shown) is stopped from the open valve state, the excitation of the attractor 25 is interrupted, and the plunger 30 descends due to the biasing force of the valve-closing spring 26. When the pilot valve body 31 seats on the pilot valve seat 15f and blocks the pilot valve port 15e, the pressure in the back pressure chamber BC and the gap space CS increases, and as the pilot valve body 31 descends, the sliding surface 15c slides against the inner surface of the guide pipe 32 while the main valve body 15 descends, and the tapered surface 15d seats on the valve seat 14, returning to the closed valve state.

(Effects of this embodiment)
If the main valve body 15 were to slide directly against the side wall 12 of the valve body 10, the following problem would arise. The side wall 12 of the valve body 10 can be formed with high precision by machining, but if the valve body 10 is made of brass, when the inlet pipe IT is brazed to the inlet opening 12a, thermal deformation may occur, reducing the roundness, which may cause sticking (catching) when the main valve body 15 slides against the valve body 10. For this reason, it is necessary to machine the inner circumference of the side wall 12 after the brazing process to form a smooth sliding surface.

If the inner circumference of the side wall 12 is not machined, the overall length of the valve body 10 and the pilot-operated solenoid valve 1 can be increased to avoid the effects of thermal deformation, so that the sliding surface of the side wall 12 of the valve body 10 can be separated as far as possible from the inlet opening 12a. However, since the inner circumference of the valve body 10 on which the main valve element 15 slides is separated from the valve seat 14, the main valve element 15 is prone to tilting, which may result in fluid leakage when the valve is closed.

In contrast, according to the present embodiment, the guide pipe 32, which has high roundness and small distortion caused by heat, is fitted to the inner circumference of the side wall 12, and the main valve body 15 slides along the inner circumference of the guide pipe 32. Therefore, even if thermal deformation occurs when the inlet pipe IT is brazed to the inlet opening 12a, the main valve body 15 can slide smoothly. In addition, since the inner circumference of the guide pipe 32 on which the main valve body 15 slides is located close to the valve seat 14, the main valve body 15 is less likely to tilt, and fluid leakage when the valve is closed can be suppressed. Furthermore, since both the plunger 30 and the main valve body 15 slide along the inner circumference of the guide pipe 32, the concentricity of the plunger 30 and the main valve body 15 can be ensured via the guide pipe 32. In addition, the outer peripheral surface of the guide pipe 32 (at least the entire area corresponding to the sliding surface of the main valve body 15) serves as a brazing allowance, and this brazing allowance and the sliding surface of the main valve body 15, which is the inner peripheral surface of the guide pipe 32, overlap in the direction perpendicular to the axis L, so the overall length of the pilot-operated solenoid valve 1 can be made shorter.

[Second embodiment]
2 is a vertical cross-sectional view showing a pilot type solenoid valve 1A of the second embodiment, showing the state in which the valve is closed. The pilot type solenoid valve 1A of this embodiment differs from the first embodiment in the configuration of the guide pipe 32A. The other configurations are the same as those of the above-mentioned embodiment, so the same reference numerals are used and the description is omitted. It goes without saying that the guide pipe 32A also serves as a sleeve in this embodiment.

The guide pipe 32A is fixed by brazing its outer circumferential surface to the inner circumferential surface of the side wall 12 with its lower end extended and in contact with the upper surface of the bottom wall 13 of the valve body 10. The guide pipe 32A has a circular or semicircular notch 32Ab cut out opposite the circular opening 12c. The valve chamber VC in the guide pipe 32A communicates with the inlet opening 12a via the notch 32Ab.

According to this embodiment, the lower end of the guide pipe 32A is abutted against the upper surface of the bottom wall 13 of the valve body 10, so that the inner peripheral surface of the guide pipe 32A on which the main valve body 15 slides can be positioned even closer to the valve seat 14. In addition, the guide pipe 32A bottomed out on the bottom wall 13 serves as a skeleton and contributes to improving the rigidity of the valve body 10, so that, for example, the thickness of the side wall 12 of the valve body 10 can be made thinner. Furthermore, the brazing allowance of the guide pipe 32A can be extended toward the valve seat 14 side from the sliding surface of the main valve body 15, and the brazing allowance between the guide pipe 32A and the valve body 10 can be made longer, so that the axial length of the side wall 12 can be shortened accordingly, thereby reducing the overall length of the valve body 10.

[Third embodiment]
3 is a vertical cross-sectional view showing a pilot type solenoid valve 1B of the third embodiment, showing the state when the valve is closed. The pilot type solenoid valve 1B of this embodiment differs from the first embodiment in the configurations of a valve body 10B, a guide pipe 32B, a stopper 33B, and a sleeve 36B. The other configurations are the same as those of the above-mentioned embodiments, so the same reference numerals are used and the description is omitted.

The valve body 10B has a cylindrical fitting wall 12Bd extending upward from the upper end of the side wall 12B. The inner diameter of the fitting wall 12Bd is larger than the inner diameter of the side wall 12B, and the thickness of the fitting wall 12Bd is thinner than the thickness of the side wall 12B.

The sleeve 36B is a thin-walled circular tube made of, for example, SUS (stainless steel). The outer diameter of the sleeve 36B is approximately equal to the inner diameter of the side wall 12B, and its thickness is thinner than the thickness of the guide pipe 32B.

The outer diameter of the annular stopper 33B and the outer diameter of the guide pipe 32B are approximately equal to the inner diameter of the fitting wall 12Bd.

During assembly, the sleeve 36B is inserted from above (fitted here) into the inner periphery (insertion opening 12Bp) of the side wall 12B of the valve body 10B, and pressed in until the upper end of the sleeve 36B coincides with the step of the side wall 12B and the fitting wall 12Bd. At this time, it is preferable to form a stopper 33B so that the upper end of the sleeve 36B is engaged with the step of the fitting wall 12Bd. It is preferable that the lower end of the sleeve 36B is located below the upper end of the circular opening 12Bc of the side wall 12B. However, the lower end of the sleeve 36B may abut against the bottom wall 13B. In that case, no stopper is provided at the upper end of the sleeve 36B, and a notch corresponding to the circular opening 12Bc is provided at the lower end of the sleeve 36B. When the lower end of the sleeve 36B abuts against the bottom wall 13B, the vertical length of the side wall 12B can be shortened.

Then, the stopper 33B is inserted into the fitting wall 12Bd, and its lower surface is brought into contact with the upper end of the sleeve 36B. Furthermore, the lower end of the guide pipe 32B is fitted into the inner circumference of the fitting wall 12Bd, and its lower surface is brought into contact with the upper surface of the stopper 33B. As a result, the stopper 33B is sandwiched between the guide pipe 32B and the sleeve 36B and is coaxially aligned.

Then, the guide pipe 32B, stopper 33B, and sleeve 36B are fixed to the valve body 10B by brazing.

When the pilot solenoid valve 1B is in operation, the main valve body 15 slides along the inner circumferential surface of the sleeve 36B and is stopped by the stopper 33B.

According to this embodiment, the sleeve 36B, which has high roundness and small distortion caused by heat, is fitted to the inner circumference (insertion opening 12Bp) of the side wall 12B, and the main valve body 15 slides along the inner circumference of the sleeve 36B. Therefore, even if thermal deformation occurs when the inlet pipe IT is brazed to the inlet opening 12a, the main valve body 15 can slide smoothly. In addition, since the inner circumference of the sleeve 36B on which the main valve body 15 slides is located close to the valve seat 14, the main valve body 15 is less likely to tilt, and fluid leakage when the valve is closed can be suppressed. The distortion caused by heat in the guide pipe 32 and sleeve 36B is at least smaller than when brass is used.

This specification includes the disclosure of the following inventions.
(Invention A)
a valve body including a valve chamber communicating with an inlet opening and an outlet opening, and an insertion opening communicating with the valve chamber;
a pilot valve body that is movable relative to the valve body;
a main valve body that is movable so as to seat on or separate from a valve seat in the valve chamber;
a sleeve inserted into the insertion opening;
The main valve body slides along the inner circumferential surface of the sleeve.
A pilot operated solenoid valve.

(Invention B)
When viewed from the axial direction of the inlet opening, a lower end side of the sleeve is disposed at a position overlapping with the inlet opening,
The pilot-operated solenoid valve of Invention A, characterized in that the portion of the sleeve facing the inlet opening is cut out.

(Invention C)
A plunger that holds the pilot valve body slides along the inner circumferential surface of the sleeve.
A pilot-operated solenoid valve according to Invention A or B.

(Invention D)
A stopper against which the main valve body abuts is attached to the inner periphery of the sleeve by crimping a part of the sleeve.
The pilot type solenoid valve according to any one of Inventions A to C.

(Invention E)
A guide pipe in which a plunger holding the pilot valve body slides also serves as the sleeve.
The pilot type solenoid valve according to any one of Inventions A to D.

(Invention F)
a stopper against which the main valve body abuts is sandwiched between a guide pipe, in which a plunger holding the pilot valve body slides, and the sleeve;
The pilot-operated solenoid valve of Invention A.

(Invention G)
An inner peripheral surface of the sleeve on which the main valve body slides and an outer peripheral surface of the sleeve brazed to the valve body overlap in a direction perpendicular to the axis of the main valve body.
The pilot type solenoid valve according to any one of Inventions A to F.

The pilot valve includes a plunger for holding the pilot valve body, an attractor for magnetically attracting the plunger, and a coil for magnetizing the attractor.
A pilot type solenoid valve according to any one of Inventions A to G.

Reference Signs List 1, 1A, 1B Pilot solenoid valve 10, 10B Valve body 12, 12B Side wall 12a Inlet opening 12p, 12Bp Insertion opening 13 Bottom wall 13b Outlet opening 14 Valve seat 15 Main valve body 18 Valve opening spring 20 Electromagnetic actuator 22 Coil unit 25 Attractor 30 Plunger 31 Pilot valve body 32, 32A, 32B Guide pipe 33, 33B Stopper 36B Sleeve VC Valve chamber

Claims (7)

a valve body including a valve chamber communicating with an inlet opening and an outlet opening, and an insertion opening communicating with the valve chamber;
a pilot valve body that is movable relative to the valve body;
a main valve body that is movable so as to seat on or separate from a valve seat in the valve chamber;
a sleeve inserted into the insertion opening;
The main valve body slides along the inner circumferential surface of the sleeve ,
A plunger that holds the pilot valve body slides along the inner circumferential surface of the sleeve,
A ring-shaped stopper against which an upper portion of the main valve body abuts is attached to the inner periphery of the sleeve by crimping a part of the sleeve.
A pilot operated solenoid valve. a valve body including a valve chamber communicating with an inlet opening and an outlet opening, and an insertion opening communicating with the valve chamber;
a pilot valve body that is movable relative to the valve body;
a main valve body that is movable so as to seat on or separate from a valve seat in the valve chamber;
a sleeve inserted into the insertion opening;
The main valve body slides along the inner circumferential surface of the sleeve,
a guide pipe on which a plunger holding the pilot valve body slides and an annular stopper against which an upper portion of the main valve body abuts is sandwiched between the guide pipe and the sleeve;
A pilot operated solenoid valve. When viewed from the axial direction of the inlet opening, a lower end side of the sleeve is disposed at a position overlapping with the inlet opening,
2. The pilot type solenoid valve according to claim 1, wherein a portion of the sleeve facing the inlet opening is cut out. A guide pipe in which a plunger holding the pilot valve body slides also serves as the sleeve.
2. The pilot operated solenoid valve according to claim 1. An inner peripheral surface of the sleeve on which the main valve body slides and an outer peripheral surface of the sleeve brazed to the valve body overlap in a direction perpendicular to the axis of the main valve body.
3. The pilot-operated solenoid valve according to claim 1 or 2 . The pilot valve includes a plunger for holding the pilot valve body, an attractor for magnetically attracting the plunger, and a coil for magnetizing the attractor.
3. The pilot-operated solenoid valve according to claim 1 or 2 . A valve-opening spring made of a coil spring is disposed between the bottom of the main valve body and the bottom wall of the valve body and biases the main valve body in a valve-opening direction relative to the valve body.
3. The pilot-operated solenoid valve according to claim 1 or 2.

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