JPS5831509B2 - pilot operated control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pilot-operated fluid control valve particularly suitable for use in contaminated fluid systems.

For example, cutting oil for gun drills is 70kg/Cr.
After being pressurized to a relatively high pressure of about rL and injected into the processing area, it is collected in an oil pan in a passage open to the outside air and used again under pressure, so it is extremely contaminated with fine chips and foreign matter mixed in from the outside air. Therefore, even if a filter is installed in the circuit to prevent malfunction of the fluid control valve, it will become clogged in a very short period of time, requiring a great deal of effort to replace and clean, making it extremely uneconomical. Therefore, there is a need for a valve that is less likely to malfunction due to contamination and does not require the installation of a filter.

However, the conventional pilot-operated fluid control valve
As shown in Publication No. 5-39, the pressure on the inlet side is applied to the main valve body that opens and closes between the inlet and outlet passages by moving in the axial direction of the guide hole so as to leave the main valve seat and sit on the main valve seat. The pressure and spring force of the main valve back pressure chamber, which communicates with the inlet side through the throttle passage, are applied in the opening direction and in the closing direction, and the main valve back pressure chamber is communicated with the low pressure side by operating the pilot valve. The main valve body is operated to open.

However, because the main valve body is slidably fitted into the cylindrical guide hole and the throttle passage is formed in the main valve body using a small diameter hole, cutting oil may leak into the sliding part of the main valve body. It was not possible to use the device satisfactorily due to drawbacks such as the tendency for foreign matter to get caught in the small diameter hole, the restriction passage of the small diameter hole to be easily blocked by foreign matter, and frequent malfunctions.

The present invention aims to eliminate such drawbacks, and aims to reduce the influence of foreign matter mixed in the fluid by tilting and swinging the main valve body within the guide hole.

Therefore, in the present invention, either the seating portion of the main valve body and the main valve seat which are seated and engaged are provided in a spherical shape, and the inlet side and the main valve back pressure chamber are communicated with the outer periphery of the main valve body in the guide hole. The technical means is to form an annular gap to form a throttle passage, and there is an annular gap between the main valve body and the guide hole, and the main valve Since the body can be tilted and swung within the guide hole, foreign matter that has entered the gap can be flushed out by the fluid, and the influence of foreign matter mixed in the fluid can be reduced.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Reference numeral 1 denotes a valve body, which is composed of a lower body 1a, an upper body 1b, and a lid body 1c that are integrally connected.

An inlet passage 2 and a guide hole 3 are bored in the lower body 1a, and these are communicated by an inlet chamber 4 formed by an annular groove provided coaxially with the guide hole.

Reference numeral 5 denotes an outlet passage provided coaxially with the guide hole 3 and communicating with the inlet chamber 4, and a cylindrical body 6 forming the main valve seat A is press-fitted and fixed at the opening end to the inlet chamber.

A bushing 7 is sandwiched between the upper main body 1b and the lower main body 1a at the end of the guide hole 3 facing the cylinder 6, and a series of large diameters extend from the end of the bush 7 on the side of the cylinder 6 to the other end. A hole 8a and a small diameter hole 8b are formed through the hole 8a in a stepped manner.

The opening edge of the small diameter hole 8b relative to the large diameter hole 8a forms a pilot valve seat B, and the small diameter hole 8b is connected to the outlet passage 5 by passages 9a and 9b bored in the upper body 1b and the lower body 1a. It's communicating.

10 is a spherical main valve body with a diameter slightly smaller than the cylindrical guide hole 3, and its spherical part is seated on the main valve seat A for sealing engagement, and a part of the ball is seated on the bush γ side. is cut out to form a recess 10a that receives one end of the spring 11 that applies a pressing force in the seating direction.

The outer surface of the main valve body 10 gradually bulges toward the inner surface of the guide hole 3 according to the spherical shape, and the cross section along the axis of the guide hole forms an annular convex portion 10b having an arc shape as shown in the figure. The amount of protrusion is maximum on a plane perpendicular to the guide hole axis passing through the main valve body, and the radial gap is minimum between the outer surface of the main valve body and the inner surface of the guide hole, forming an annular throttle passage R.

In the guide hole 3, by installing the main valve body 10, a main valve back pressure chamber Z is formed which communicates with the inlet chamber 4 through the throttle passage R.

Reference numeral 12 denotes a pilot valve body that is fitted into a large diameter hole 8a provided in the bushing 7, and the spring 11 is seated on the pilot valve seat B with the spherical part of a steel ball 12a press-fitted into the tip.
The other end is received and pressed.

The pilot valve body has a maximum diameter smaller than the large diameter hole 8a,
It has a barrel shape with an arcuate cross-sectional shape and an annular convex portion 12b protruding toward the inner surface of the large diameter hole, and further has a plurality of flow grooves 12c on the outer surface.

13 is a push rod whose one end comes into contact with the steel ball 12a of the pilot valve body 12;
It extends out of the valve body through the through hole 14 provided in c, and comes into contact with the movable core 15a of the electromagnetic device 15 installed on the lid body 1c at the other end, and is fixed by energizing the coil 15b of the electromagnetic device. The pilot valve body 12 is pushed downward by the movable iron core attracted to the iron core 15c, and is removed from the pilot valve seat B.

A wiper ring 16 is installed on the end surface of the bush 7 in which the small diameter hole 8b opens and engages with the outer periphery of the push rod 13.

Further, 17, 18, and 19 are well-known seal rings.

Next, the operation of this embodiment will be explained.

The inlet passage 2 is connected to a fluid pressure source such as cutting oil, and the outlet passage 5 is connected to a fluid pressure source such as cutting oil.
It is assumed that the coil 15b of the electromagnetic device 15 is not energized in the illustrated state.

Then, the pressure on the inlet side is introduced into the main valve back pressure chamber Z, which communicates with the inlet chamber 4 via the throttle passage R, and the pilot valve body 12
is pressed by the spring force of the spring 11 and the pressure of the main valve back pressure chamber Z and seats on the pilot valve seat B, and the main valve body 10 has a cross-sectional area corresponding to the spring force of the spring 11 and the cross-sectional area of the main valve seat A. It is pressed by the pressure of the main valve back pressure chamber Z acting on the pressure receiving area and is seated on the main valve seat A, closing the inlet and outlet passages 2 and 5.

When the coil 15b is energized, the movable iron core 15a is attracted to the fixed iron core 15c by the generated magnetic force, and the piston 14P body 12 is pushed downward via the push rod 13 to be removed from the valve seat B.

As a result, the fluid in the main valve back pressure chamber Z passes through the annular gap between the outer surface of the pilot valve body 12 and the inner surface of the large-diameter hole 8a and the circulation groove 12c, and then flows into the small-diameter hole 8b and into the passage 9a.

9b to the outlet passage, and by the action of the throttle passage R interposed between the back pressure chamber 2 and the inlet chamber 4, the pressure in the back pressure chamber 2 is reduced to approximately the pressure in the outlet passage.

Therefore, the main valve body 10 is pressed by the pressure of the inlet chamber 4 and rises to be separated from the main valve seat A, and the inlet and outlet passages 2.
5 is open and conductive.

Then, when the power supply to the coil 15b is stopped, the pilot valve body 12 is seated on the pilot valve seat B by the spring force of the spring 11 to cut off the connection between the main valve back pressure chamber 2 and the outlet passage 5.
The pressure in the back pressure chamber 2 rises to the pressure in the inlet chamber 4, and the main valve body 10 again seats on the main valve seat A, resulting in the state shown in the figure in which the inlet and outlet passages 2 and 5 are closed.

In this operation, the main valve body 10 is not directly slidingly fitted to the inner surface of the guide hole 3, but can be displaced in the radial direction and can be swung so that the axis is tilted, so that foreign matter mixed in the circulating fluid is mainly removed. Even if the main valve body 10 enters the throttle passage R where the radial gap is the smallest between the valve body 10 and the guide hole 3, the main valve body 10 can be displaced appropriately until it comes into contact with the inner surface of the guide hole 3, and the throttle passage R is just a small diameter. Since it is not a hole but an annular shape, the foreign matter that has entered is washed away by the fluid flowing around it.

Therefore, the possibility that the main valve body 10 gets caught in foreign matter and sticks to the inner surface of the guide hole 3, causing malfunction, is extremely reduced.

The pilot valve body 12 also has a maximum diameter smaller than that of the large diameter hole 8a, allowing fluid to flow around its outer periphery, and like the main valve body 10, can be displaced within the dog diameter hole 8a, making it difficult for foreign objects to get caught. Even if foreign matter adheres to the outer periphery of the push rod, it is scraped off by the wiper ring 16 each time the operation is performed, thereby preventing foreign matter from entering the through hole 14.
This prevents the seal ring 17 from sticking to the inner surface or damaging the seal ring 17.

Further, even if the main valve body 10 and the pilot valve body 12 are temporarily displaced in an equal manner such that their axes are tilted when the foreign matter is discharged, they are subjected to an alignment action by the spring 11, and both valve bodies have a spherical surface. Since it seats on each valve seat A and B and closes,
Even if these axes are slightly deviated when the valve is seated, it can be closed well, and even if the valve bodies contact the inner surfaces of the guide hole 3 and the large diameter hole 8a, each of the annular convex portions 10b and 12b has an arcuate cross section. Contact stress is reduced, and wear etc. are less likely to occur.

In this control valve, when the outlet passage 5 is communicated with the high pressure side and the inlet passage 2 is communicated with the low pressure side, the pilot valve element 12, which has a higher cracking pressure than the main valve element 10, remains seated and the main valve element is connected to the main valve seat. Since it is separated from A and becomes a free flow, it can be used as a type of pilot check valve that is electromagnetically operated as necessary.

In this example, the annular convex part was provided on the main valve body side, but it can also be provided on the inner surface of the guide hole if necessary.Furthermore, although the seating part of the main valve body was made into a spherical shape, the main valve seat side was made into a spherical shape. It is clear that the present invention can also be applied to pressure control valves such as pilot-operated relief valves.

As described above, according to the pilot-operated fluid control valve of the present invention, either the seating portion of the main valve body or the main valve seat is provided in a spherical shape,
Since the main valve body tilts and oscillates while being displaced and securely seats and engages with the main valve seat, the cylindrical main valve body is fitted into the guide hole with a gap formed therein. However, compared to the conventional method, it has unique effects such as being able to better close the inlet and outlet passages and providing stable operation when installed in a fluid system with many foreign substances.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an embodiment of the present invention. 2... Entrance passage, 3... Guide hole, 5...
...Outlet passage, 10...Main valve body, 10b
......Annular convex portion, 11... Spring, 12.
...-Pilot valve body, A...Main valve seat, R
... Throttle passage, Z... Main valve back pressure chamber.

Claims (1)

[Claims] 1 Move in the axial direction of the guide hole away from the main valve seat and seated on the main valve seat, and transfer the inlet side pressure to the main valve body that opens and closes between the inlet and outlet passages in the opening direction, and between the inlet side and the throttle passage. A pilot operation in which the pressure and spring force in the main valve back pressure chamber communicated through the valve are applied in the closing direction, and the movement of the pilot valve body communicates the main valve back pressure chamber to the low pressure side and opens the main valve body. In a fluid control valve, either the seating portion of the main valve body and the main valve seat that are seated and engaged are provided in a spherical shape, and an annular shape is provided on the outer periphery of the main valve body in the guide hole to communicate between the inlet side and the main valve back pressure chamber. A pilot operated fluid control valve characterized in that a gap is formed to serve as a throttle passage.