JP3146056B2 - Pressure relief valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pressure relief valve for use as a pilot valve for a single-stage valve or a two-stage pressure control valve. And a pressure relief valve that can also be applied to gas and liquid valves.

[0002]

2. Description of the Related Art Conventionally, in this type of proportional solenoid type pilot relief valve, a movable iron core is driven by energizing a solenoid, and a force generated by the movable iron core is transmitted to a poppet valve body via a spring, and a poppet valve is provided. The relief pressure is set by pressing the valve body against the seat, and the relief pressure proportional to the current flowing through the solenoid can be variably set.

However, such a conventional proportional solenoid pilot relief valve has a processing capacity of only about 1 liter / min in terms of flow rate, and the pilot liquid of the relief main valve having a large size at a general large flow rate. By controlling the pressure with a proportional electromagnetic pilot relief valve, pressure control with high flow relief is realized. In the case where the pilot hydraulic pressure of the relief main valve is pressure-controlled, the pilot relief flow rate that changes relatively in proportion to the movement of the relief main valve having a large relief flow rate flows to the tank side. When the relief flow rate changes relatively little, the change to the poppet valve is small, and the proportional electromagnetic pilot relief valve can perform very smooth pressure control as a pilot valve.

[0004]

However, in order to control the pressure with the conventional proportional electromagnetic pilot relief valve alone, the proportional electromagnetic pilot relief valve and the relief main valve are incorporated in, for example, one block, and rigidity is reduced by a small volume. When the pressure is controlled by installing the poppet valve at a high position (without using a hose or the like), there is a problem that the poppet valve element causes physical transmission (pulsation) of a very high frequency exceeding 500 Hz, which causes anxiety.

The pulsation of the poppet valve element is caused by the resonance frequency of the poppet valve element and the spring, and is far from the resonance frequency of the movable core having a damper function. However, there is almost no suppression effect, and the adverse effect of rather slowing down the response of the movable core is caused. SUMMARY OF THE INVENTION It is an object of the present invention to provide a stable pressure relief valve which has a low pressure and has a hysteresis in a control current.

[0006]

In order to achieve this object, the present invention is configured as follows. A valve body (1) having a valve seat (12); and a valve seat (1) attached to the valve body (1).
2) a valve closing member (13) for controlling the flow of fluid flowing from the inlet pressure port (P) to the outlet tank port (T) through the valve, and elastic means (29) according to the magnitude of the supplied control current. ) Electromagnetic control means (25) having a push pin (26) capable of moving the valve closing member (13) via
And an anti-cavitation disposed downstream of the valve seat (12).
And the push pin (26).
And disposed the damper means (37) between the valve closing member (13), the valve closing member (13) is flat and ends in a cylinder, the valve seat (12) is Ri tapered der, anti Cavitation
Ring (19) supplies fluid between the tank port (T)
It has a connecting hole . In addition, valve seat (1
2) The hole in the anti-cavitation ring (19) facing
The end (21) is stretched outward in the direction of the valve seat (12).
It is characterized by putting out. Also anti-cavitation ring
The end (21) projecting outward from the hole of (19) is a curved surface
It is characterized by having. Also facing the valve seat (12)
End (21) of the anti-cavitation ring (19)
Is approximately perpendicular to the axis of the valve closing member (13)
It is characterized by. Also anti-cavitation ring (19)
The other end of the hole is slidingly fitted to the valve closing member (13).
It is characterized by having such dimensions.

In the pressure relief valve according to the present invention, damper means is provided between the push pin and the poppet. The damper means is an armature of electromagnetic control means which may be a solenoid and a poppet. Acts to damp any relative vibrations during the operation to increase valve stability. The push pin typically moves the poppet via intermediary elastic means in the form of a return or cushion spring acting between two spring seats facing the push pin and the poppet, respectively.

[0008] The damper means in the preferred embodiment of the first invention is in the form of a dash pot, and comprises a piston moving through one spring seat and a cylinder moving through the other spring seat. The dashpot piston may be formed integrally with one of the spring seats, or may be separately formed and attached to the spring seat by bonding or other means. The dashpot cylinder is mounted on the other spring seat, for example to form a blind hole, or to facilitate manufacture,
Instead of a blind hole, a through hole may be formed, and one end of the through hole may be closed after manufacturing by a suitable sealing means.

In an alternative embodiment of the first invention, one spring seat is itself formed as a dashpot piston and the other spring seat is formed as a dashpot cylinder with a return spring itself located within the cylinder. Good. It is convenient to provide a suitable gap between the dashpot piston and the cylinder to provide the required damping, but the cylinder may be provided with other means such as a vent.

A second aspect of the present invention is directed to a valve body having a valve seat, and a poppet mounted within the valve body and cooperating with the valve seat to control the flow of fluid flowing from the inlet pressure port to the outlet tank port through the valve. And including an anti-cavitation ring disposed downstream of the valve seat, the hole being drilled in the ring to allow fluid to flow between the hole in the ring and the tank port. Features.

The end of the ring facing the valve seat and the valve seat itself can be of any shape, but their shape and relative position are such that they deflect the fluid flowing out of the gap between the poppet and the valve seat. It is to be. With this configuration, cavitation can be reduced. The combined angle of the valve seat and the ring end is desirably such that the fluid flowing therethrough can be deflected through an angle of at least 60 degrees, and a larger deflection angle can enhance the anti-cavitation effect. Thus, the ring end may be, for example, a plane generally perpendicular to the axis of the poppet, a truncated cone, or a curved surface.

According to the second aspect of the present invention, by providing an anti-cavitation ring, cavitation and noise due to the cavitation, corrosion, and the like can be sufficiently sufficiently prevented, and the stability of the flow flowing through the valve, the endurance and stability of the valve, and the like can be improved. Can be increased. In addition, by sizing the hole at the opposite end of the ring member with a poppet,
It was found that it was further improved.

With such an arrangement, very good valve stability can be obtained when the tank port and the use of a small orifice for pressure are combined.
Unfortunately, however, the use of a small orifice will generate high pressure when the valve deenergizes. If the damper means of the first invention is incorporated into the pressure relief valve of the second invention in order to solve such a problem, the size of the orifice can be enlarged.

The provision of the anti-cavitation ring of the second invention causes the fluid to collide with the resistance cavitation ring, resulting in a local decrease in fluid velocity and an increase in static pressure. Such increased static pressure avoids the risk of fluid cavitation and associated pressure instability,
Or decrease it. The cavitation ring can be used with a generally cylindrical end poppet and a tapered valve seat (or vice versa), or a bi-tapered valve seat and poppet can be used. .

Another factor in achieving valve stability is that when the valve is used, fluid is introduced and exhausted of the air stored in the solenoid section. In the proportional pressure relief valve, the air remaining in the solenoid part can be introduced into the fluid by moving the solenoid push pin when controlling the position of the poppet.However, even when the valve is not driven, the air leaks every moment. Incoming air can be introduced and discharged. However, some conventional pressure relief valves cause pressure instability in the form of 20-100 Hz vibrations due to air remaining in the solenoid.

The valve according to the second invention of the present application may be a proportional valve,
The push pin of the electromagnetic proportional control means is preferably hollow. In the first invention of the present application, a hollow push pin may be used. When the hollow push pin is used, the hollow push pin can send out most of the air supplied to the solenoid portion into the fluid by driving the armature by the control means, and replace the supplied air portion with the fluid. . Further, the hollow push pin works together with the solenoid and the push pin to prevent the occurrence of a pressure difference that impairs stability between both ends when the pressure rises.

The restrictor or orifice can be located at the tank port and is dimensioned to increase the pressure inside the valve and the electromagnetic control as the flow through the valve increases. For rapid flows, this increase in pressure
Because of the hollow pushpin, it is first added to the end of the iron core furthest from the poppet before being fed to the end of the iron core closest to the poppet.

As a result of this sequence of transient pressure changes, the core is depressed toward the poppet and then moves toward the valve seat to attempt to reduce, rather than increase, flow surge. As a result, the order of supplying the pressure to the iron core is reversed. For that reason, it is desirable to arrange the hollow pushpin to be a powerful coupling between the upstream of the orifice flow in the tank port and the electromagnetic control means.

Conventionally, in order to use the same material as a known solid push pin used for a pressure relief valve, an attempt was made to make a hollow push pin using a very hard grade stainless steel (30HRC grade). . However, it was immediately recognized that this class of stainless steel was unsuitable for manufacturing a 70 mm long push pin having a through hole with a diameter of 2 mm in the processing stage. Hollow push pins must satisfy the following requirements.

A) Being substantially non-magnetic (for effective operation of the electromagnetic control means). b) have a hard surface on at least a part of the outer diameter of its length, where it can withstand the rolling action of the ball bearing; c) It must be a material that can be easily processed to be perforated and / or tubular. d) A low-friction finish, for example constructed like PTFE, which is compatible with bushing bearings in part of its length.

As an example of a suitable material of the easier-to-work class of stainless steel, the first choice was 18 /
10 austenitic stainless steel, which in relative softness needed to provide a solid outer surface. Attempts were made to use 0.05mm thick electrodeposited chrome plating as currently used in solenoids, but this proved unsatisfactory. That is, the loading force was such that it caused notching after a relatively short test period. A plasma nitridation process, also known as the creation of very hard surfaces (of the order of 1000 Hv), was also tested, but it produced distortion, unsatisfactory push pin linearity, and undesired slight matte finish.

The PTFE nickel material was also used for electrodeposition, but the hardness did not pass the durability test and was unsatisfactory. Next, first, electrodeposition nickel plating was attempted using a 6 to 10% phosphorus-containing medium. Although the hardness provided on the surface of the push pin was satisfactory as a whole, it was thought that there was a difference in the content of phosphorus within the specification range of 6 to 10%, so that the value changed every plating. . Phosphorus content will impart hardness and ductility to the plating surface.

Finally, relatively high phosphorus content (10% +)
The electrodeposited nickel was tested at the heat treatment temperature after plating.
The push pins heat treated at 400 ° C. failed after a 15 × 10 ⁶ cycle endurance test, and plating failure indicated lack of ductility of the plating. Therefore, when the heat treatment temperature was lowered to 300 ° C. and the hardness was tested, it was reduced. The third invention of the present application provides a method for manufacturing a push pin for electromagnetic control means, comprising the following first to fourth steps.

[First Step] A raw material of a workable non-magnetic material for manufacturing a push pin is provided. [Second Step] From the raw material obtained in the first step, a push pin having a required size and shape is prepared. [Third step] At least 10% by weight of phosphorus is contained or at least 1% by weight on the outside of the push pin prepared in the second step.
The electrodeposited nickel has a boron content of from 5% to 5%.

[Fourth Step] The push pin coated in the third step is heated at a temperature of 250 ° C. to 350 ° C. Although the third invention is applicable to solid and hollow push pins, the advantage of using a workable material is applicable to both, and particularly to hollow push pins. .

The raw material used for the push pin is about 3
18/10 austenitic stainless steel with a hardness of 00 Hv is preferred. This third invention is beneficial when the first invention and the town are used together with the second invention. Another problem with pressure relief valves is that they have high hysteresis due to friction between the poppet and its guide means. Furthermore, accurate centering between the poppet and the valve seat is a next problem. If the guidance of the reciprocation of the poppet with respect to the valve seat is not controlled correctly, its exact centering may be impaired.

A fourth invention of the present application is directed to a pressure relief valve including a valve body having a valve seat, and a poppet that cooperates with the valve seat to control the flow of fluid flowing from a pressure inlet port to an outlet tank port. Wherein the poppet is guided to move toward and away from the valve seat by means of a guide having at least one linear bearing using a rotating member.

The use of such a guide poppet provides good and low hysteresis, reduces leakage when used with a proportional pressure relief valve, and allows accurate centering with the valve seat to provide good repeatability. I understand. In addition, the use of flat bush bearings for ball or roller bearings allows the use of dirty fluids.

The linear bearing may be included in a housing formed integrally with the valve seat assembly or formed as a separate member centered on the vane assembly. The cage (outer frame) of the linear bearing may be configured to move together with the poppet, or may be held stationary. The feature of the poppet that is guided by using the linear bearing of the fourth invention is that of the first embodiment.
It can be used in any of the aspects of the invention to the third invention.

[0030]

According to the present invention having such a configuration, the following operation can be obtained. According to the relief valve of the first invention in which damper means is provided between the push pin and the poppet, the damper means attenuates any relative vibration between the armature of the electromagnetic control means comprising a solenoid and the poppet. Acts to increase valve stability.

According to the second invention in which the anti-cavitation ring is disposed downstream of the valve seat, the cavitation is reduced by deflecting the fluid flowing out of the gap between the poppet and the valve seat to take away the velocity component. Can be.
In the push pin manufacturing method according to the third aspect of the present invention, the push pin is substantially non-magnetic, has a surface hardness that can withstand the rotating action of the ball bearing, can be easily formed into a perforated or tubular shape, and has a portion in the longitudinal direction. A hollow pushpin is obtained that allows a low friction finish compatible with bushing bearings.

Further, according to the fourth aspect of the present invention using the linear bearing as the means for guiding the poppet, a low hysteresis is provided when the poppet is guided and guided, and when used for a proportional pressure relief valve, leakage is reduced and good repeatability is achieved. It can be precisely centered with the valve seat to give.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the proportional pressure relief valve of the present invention will be described below in detail with reference to the drawings. The valve shown in FIG. 1 is an electro-hydraulic proportional pressure relief valve designed to be mounted on an ISO 4401 size 3 interface. This electro-hydraulic proportional pressure relief valve is designed to regulate the pressure of the fluid pressure system in proportion to the applied electrical input, with a maximum nominal pressure and flow rate of 350 bar and 3 liters per minute, respectively. This valve can be used as a single stage valve or as a pilot valve for a large pressure control valve.

According to FIGS. 1 to 3 and FIG. 7, the pressure relief valve comprises as a whole a valve body 1 having a blind hole 2 bored oppositely to an opposite hole 3. Pressure inlet port P (FIGS. 3 and 4)
Are connected internally by a drill hole 4 (FIG. 3) and to the end of the blind hole 2 with the same diameter. A valve seat assembly 6 including a cylindrical member 7 fitted in the opposed hole 3 of the valve body 1 with a clearance and having an elongated body 8 sealed with a seal 5 in the blind hole 2.
Is sealed from the blind hole 2 by a seal 5. The cylindrical member 7 has a shaft hole 9 formed therein, and the extended body 8 has a shaft hole 11 coaxial with the shaft hole 9.

At the inner end of the shaft hole 9, a truncated cone facing hole that actually contacts the valve seat 12 is formed. The poppet (valve closing member) 13 has a small-diameter end, and has a shaft hole 9 of the valve body assembly 6.
The outer end 14 constitutes an actual poppet cooperating with the valve seat 12. The other end 15 of the poppet 13 is also reduced in diameter. The poppet 13 is fitted therein by a pair of linear ball bearings 16 for sliding movement in the axial bore 9 of the valve seat assembly 6,
Linear ball bearing 16 includes an annular cage or frame 17 on which a plurality of balls 18 are mounted for rotational movement therein.

At the inner end of the shaft hole 9 of the valve seat assembly 6 (FIGS. 2 and 7), an anti-cavitation ring 19 having a main hole into which the poppet 13 is loosely fitted is attached.
The end 21 of the hole in the ring 19 adjacent to the valve seat 14 is protruded outside and has a frustoconical shape. However, the protrusion 21 of the anti-cavitation ring 19 may have a curved surface. Diameter holes 22 are formed in the radial direction of the anti-cavitation ring 19, and the ends of the diameter holes 22 are aligned with respective radial holes 23 provided in the cylindrical member 7 of the valve seat assembly 6. Further, the radial hole 23 opens into an annular gap 20 between the cylindrical member 7 and the opposing hole 3 of the main body 1, which communicates with a tank hole 24 leading to a tank port T in which a restrictor or orifice 30 is fitted. are doing.

At the end of the main body 1 having the blind hole 2 formed therein, a push pin 26 which is not a solid but a hollow rod structure is provided.
, Except that a conventional proportional solenoid 25 is basically fitted. Although the proportional solenoid 25 in FIG. 1 is a push type, it may be a push type or a pull type. Push pin 26
The outer end (right end) is supported by a ball bearing 27, and the inner end (left end) is supported by a bearing bush 28.

Spring 29 for return or buffer
Is disposed between the poppet 13 and the push pin 26,
Each end of the spring 29 abuts against a spring seat 31,32. Each of the spring seats 31 and 32 has a through hole 33, and a piston 34 having an axial blind hole 35 and a diameter hole 36 orthogonal to the blind hole 35 is fitted into the hole 33 of the spring seat 31.

The blind hole 35 of the piston 34 is
6 and communicates with the end chamber 37 of the main body 1 and the through hole of the push pin 26, and the chamber 37 is connected to the tank port T through a passage (not shown). The end of the push pin 26 is fitted and fixed in the opposing hole 38 of the spring seat 31. The two components of the push pin 26 and the spring seat 31 move simultaneously.

The spring seat 32 for the poppet 13 has the same shape as the spring seat 31, but the end of the poppet 13 has an opposing hole 38.
It is turned in the opposite direction so as to be fitted in. The hole 33 of the spring seat 32 forms a cylinder 39 into which the piston 34 is loosely fitted by a clearance fit, and the cylinder 39 forms a dashpot structure together with the piston 34. In use of the valve, a control current is applied to the coil 41 of the solenoid 25, and the resulting magnetic field moves through the armature 42 connected to the push pin 26. Thus, the push pin 26 exits the solenoid 25 and enters the valve body 1. This push pin 26
Is transmitted to the poppet 13 via the buffer spool 29. Therefore, the poppet 13 can move toward the valve seat 12 to regulate the flow of the pressurized fluid flowing from the pressure port P to the tank port T via the valve.

The main pressure drop of the pressure fluid through the valve depends on the force acting on the poppet 13, the flow coefficient of the pressure fluid and the viscosity of the fluid. The force acting on the poppet 13 depends on the magnitude of the control current supplied to the solenoid coil 41. The high velocity fluid flowing through the shaft bore 11 of the extension 8 of the valve seat assembly 6 generates a low local static pressure, and cavitation occurs if the local static pressure is sufficiently low. The anti-cavitation ring 19 helps prevent cavitation by locating the overhanging end 21 against the effluent that impinges thereon. By placing the end of the anti-cavitation ring 19 as close as possible to the valve seat 12 and deflecting the flow along the opening plane at an angle of 90 degrees, a high anti-cavitation effect is obtained.

The occurrence of any cavitation causes the valve to become unstable due to the physical oscillation of the poppet 13. When cavitation occurs despite the presence of the anti-cavitation ring 19, the generated vibration
And the dash pot structure of the piston 34. A clearance fit between the two components restricts the passage of the fluid, thereby providing damping. The magnitude of the braking is determined by:

1. 1. Clearance between piston 34 and cylinder 39 2. Diameter of piston 34 3. Length of connection between piston 34 and cylinder 39 The viscosity of the fluid whose flow is controlled by the valve. A suitable clearance provided between the piston 34 and the cylinder 39 results in a stable operation of the valve.

The poppet 13 has a valve body assembly with two linear ball bearings 18 to provide a low coefficient of friction between the two components of the piston 34 and the cylinder 39 so that the valve can have good hysteresis. 6 are guided to slide. In addition, accurate guidance of the poppet 13 means that in fact the center between the poppet 13 and the valve seat 12 is always exactly centered and the leakage is kept low.

As already mentioned, each ball 18 rolls freely within the cage or frame 17 and the movement of the ball bear rig 18 within the frame 17 determines the stroke of the poppet 13 based on: Stroke = 2 (Ld) where L is a frame 1 in which each ball bearing 18 can move.
7 is the length of the hole, and d is the diameter of the ball. L and d are shown in FIG.

Therefore, the pressure relief valve using all of the first to fourth inventions of the present application in the embodiment is extremely stable, has a low leakage characteristic and a good hysteresis characteristic, and is remarkable as compared with the prior art. The effect can be exhibited. Next, returning to the hollow pushpin 26 again, the use of a valve using this means that there is no need to perform any outflow operation, such as bleeding air, to remove air from the solenoid 41. Most, if not all, of the air trapped in the solenoid 41 is exhausted by the movement of the pressure fluid and the armature 42. T
The orifice 30 connected to the port gives it sufficient back pressure. However, as noted above, special care must be taken in the manufacture of push pins 26.

This is because it is not practical to manufacture such a push pin 26 in a manufacturing process using a hard stainless steel raw material because of difficulties in processing. The manufacture of the push pin 26 according to the fourth invention of the present application is as follows.
It is made from a machinable or machinable austenitic stainless steel, which is a substantially non-magnetic material, and has already been machined into either hollow or solid push pins. One austenitic steel has a hardness of about 300 Hv
Known as austenitic stainless steel.

After the through-hole is formed in the push pin 26, the nickel-phosphorus alloy is coated by using an electroplating technique, and the nickel-boron alloy is coated by using the same technique. A hard, low friction bearing can be provided on the outer and / or inner surface of the 26. When a nickel-phosphorus alloy is used, the phosphorus content is preferably from 10% to 14% by weight. When a nickel-boron alloy is used, the boron content is preferably 1% to 5% by weight. After plating, the push pins 26 are heat treated to improve surface hardness and plating adhesion. When a nickel-phosphorus alloy was used, it was found that satisfactory results could be obtained by heat treatment at 300 ° C. for 1 hour.

The plating is PTFE type bush bearing 2
8 provides a hard, durable surface for the push pin 26 that can be used with the ball bearing 27.
The remarkable effect of this plating technique is that after plating and heat treatment,
No further processing or other processing is required. Returning to FIG. 5, this embodiment shows an alternative construction of the spring seats 31, 32 which is not identical to that of the embodiment of FIG.

The spring seat 31 has an integrally formed dashpot piston 34 having a blind hole 35 and a right-angled hole 36 as described above. A blind hole 43 forming a cylinder 39 is provided in the spring seat 32, and a blind hole 43 at the other end of the spring seat 32 is provided.
Another blind hole 44 is formed coaxially with the poppet 13, and the poppet 13 is loosely fitted in the blind hole 44. While this structure works satisfactorily as a dashpot structure, it requires two blind holes, which increases manufacturing costs because both spring seats cannot be made identical.

FIG. 6 shows a further improved spring seat and dashpot structure. In this embodiment, the push pin 2
The spring seat 45 connected to 6 forms a piston of a dashpot configuration by itself, while the other spring seat 46 forms a cylinder 39 to which the spring piston 45 is mounted. The buffer spring 29 is disposed in the cylinder 39 and the closed end of the cylinder 39 and the spring seat piston 4
It works between 5.

FIG. 11 shows yet another spring seat and dashpot arrangement, except that the clearance between the piston 34 and the bore 33 of the cylinder 39 is narrower than that of the arrangement of FIG.
It is essentially the same as that of FIG. Further, braking can be obtained by allowing fluid to enter and exit the cylinder 39 through a restrictor formed in the form of the vent hole 48. The diameter of the vent 48 can control the degree of braking.

FIG. 8 shows an alternative structure of the anti-cavitation ring 19, which is basically the same as FIGS. 1, 2 and 7. The protruding end 21 of the anti-cavitation ring 19 of FIG. 9 has a taper or chamfer of 30 degrees and is disposed adjacent to the valve seat 12. However, anti-cavitation ring 1
9 is not a clearance fit to the poppet 13, but a lid end is provided at the inner end of the ring so that the diameter of the non-protruding end of the ring hole is reduced and a small radial clearance of about 0.2 mm is formed in the poppet 13. A part 40 is provided. It has been found that such a configuration of the overhanging end and the lid end greatly improves the stability of the valve.

FIG. 9 shows an alternative structure for guiding the poppet 13. The cage or frame 17 of the ball bearing 16 in the embodiment of FIG. 1 is fixed to the cylindrical member 7 of the valve seat assembly 6, while the structure of the frame 49 according to FIG. 9 is mounted to move with the poppet 13. Of course, the ball 18 can be rotated within the frame 49. The stroke (STOKE) of the poppet 13 having this structure is given by the following equation.

STOKE = 2 (L ₁ −L ₂ ) where L ₁ is the axial length of the place where the frame 47 can move, and L ₂ is the axial length of the frame. FIG. 10 shows an alternative shape of the anti-cavitation ring 19, the end 21 of which is located close to the valve seat 12, which is shown in FIGS. 1, 2, 7 and 8.
Is not a shape protruding outward as in
The flow will be deflected at an angle of 90 degrees or more. For example, by using the valve seat 12 having a taper of 40 degrees, the fluid is 135 degrees (= 45 degrees).
(Degrees +90 degrees).

As described above, according to the present invention, the damper means acts to attenuate any relative vibration between the armature of the electromagnetic control means comprising a solenoid and the valve closing member, thereby increasing the stability of the valve. Can be improved. Further, the valve closing member is cylindrical and the end is flat,
The valve seat is tapered, simplifying the configuration
Anti-cavitation ring and tank port located in the stream
Because it has a hole to connect the fluid between the
Cavitation can be reduced. In addition, the cavitation can be reduced by deflecting the fluid flowing out of the gap between the valve seat and the valve element to deprive the velocity component.

[0057]

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a pressure relief valve of the present invention.

FIG. 2 is an enlarged cross-sectional view of FIG. 1 on the left side;

FIG. 3 is a left side view of FIG. 1;

FIG. 4 is a bottom view of a left portion of FIG. 1;

FIG. 5 is a partially enlarged view showing another embodiment of the dashpot structure on the left side of FIG. 1;

FIG. 6 is an explanatory view showing another embodiment of the dashpot structure shown in FIG. 5;

FIG. 7 is a partially enlarged view showing another embodiment of the anti-cavitation ring of FIG. 1;

FIG. 8 is a partially enlarged view showing another embodiment of another anti-cavitation ring similar to FIG. 7;

FIG. 9 is a partially enlarged view showing another embodiment of the poppet guide shown in FIG. 4;

FIG. 10 is a partially enlarged view showing another embodiment of the anti-cavitation ring similar to FIG. 7;

FIG. 11 is a partially enlarged view showing another embodiment of the dashpot structure similar to FIG. 5;

[Explanation of symbols]

 1: Valve body 2, 35, 43, 44: Blind hole 3: Opposing hole 5: Seal 6: Valve seat assembly 7: Cylindrical member 8: Extended body 9, 11: Shaft hole 12: Valve seat 13: Poppet (valve closed) 14) Outer end 15: The other end 16: Linear ball bearing 18: Ball 19: Anti-cavitation ring 20: Annular gap 21: End 22, 36: Diameter hole 23: Radial hole 24: Tank hole 25: Proportional solenoid 26 : Push pin 27: Ball bearing 28: Bearing bush 29: Spring 30: Restrictor or orifice 31, 32, 45, 46: Spring seat 33: Through hole 34: Piston 37: End chamber 38: Opposing hole 39: Cylinder 41: Coil 42: Armor chair

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor John Leslie EL Energy P9, Hampshire, UK 2 Eque, Havant, Denvilles, Natwick Road 115 (72) Inventor Kosuke Hatanaka Asahimachi, Sano City, Tochigi Prefecture 840-1 Asahi Corporation 201 (72) Inventor Akio Mito 2168-29 Imajuku-cho, Asahi-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-48-35423 (JP, A) JP-A-3-61775 (JP) JP-A-2-38770 (JP, A) JP-A-59-205077 (JP, A) JP-A-57-90477 (JP, A) JP-A-62-115583 (JP, U) JP-A 64-7964 (JP, U) Fully open 1984-194670 (JP, U) Fully open 2-62175 (JP, U) Fully open 63-133668 (JP, U) Fully open 1987-110668 (JP, U) U) Japanese Utility Model Application 58-91071 (JP, U) Japanese Patent Publication No. 61-45103 (JP, B2) Japanese Utility Model Application Hei 2-38146 (JP, Y2) Published French Patent Application 1096559 (FR, A1) (58) Field (Int.Cl. ⁷ , DB name) F16K 17/00-17/168 F16K 31/06 F16K 47/02

Claims (5)

(57) [Claims] 1. A valve body (1) having a valve seat (12), and attached to said valve body (1) and cooperating with said valve seat (12) through a valve and out of an inlet pressure port (P). A valve closing member (1) for controlling the flow of the fluid flowing through the tank port (T)
3) and elastic means (2) according to the magnitude of the supplied control current.
An electromagnetic control means (25) having a push pin (26) movable closure member (13) said valve through 9), before
Anti-cavitation located downstream of the valve seat (12)
A ring (19) , a damper means (37) disposed between the push pin (26) and the valve closing member (13), wherein the valve closing member (13) is cylindrical and has an end portion. is flat, valve seat (12) is Ri taper der, wherein the anti Kyabite
Between the tank ring (19) and the tank port (T)
A pressure relief valve having a hole for connecting a fluid to the pressure relief valve. 2. An end (21) of a hole in the anti-cavitation ring (19) facing the valve seat (12), protruding outward in the direction of the valve seat (12). Item 2. A pressure relief valve according to item 1 . Wherein the anti-end protruding outside the bore of the cavitation ring (19) (21) is a pressure relief valve according to claim 1, characterized in that it has a curved surface. 4. An anti-cavitation ring (19) end (21) facing said valve seat (12) is substantially perpendicular to the axis of the valve closing member (13). 2. The pressure relief valve according to 1. Wherein said other end of the hole in the anti-cavitation ring (19), according to claim 2, characterized in that the sized to a sliding fit with respect to the valve closure member (13), 4
The pressure relief valve according to any one of the above.