JPH11311348A - Hydraulic relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability by weakening influence on a socket, a valve main body, etc., due to breaking of steam bubbles produced by lowering of pressure of water. SOLUTION: This hydraulic relief valve 1 positions a valve seat member 3 in a valve hole 10 between a high pressure port 11 and a low pressure port 12. Additionally, a socket 4 to hold a valve member 5 to be seated on the valve seat member 3 free to slide is arranged apart in the axial direction from the valve seat member 3 while positioning the low pressure port 12 between the socket 4 and the valve seat member 3. Consequently, it is possible to weaken influence due to breaking of steam bubbles produced at the time when water passes through the valve seat member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic relief valve for controlling water pressure by using water as a working fluid.

[0002]

2. Description of the Related Art As a conventional hydraulic relief valve, as shown in FIG. 4, there is a hydraulic relief valve having a main valve PB and a pilot valve CB. The hydraulic relief valve shown in FIG.
A valve body 100 having a high pressure port 101 and a low pressure port 102, a valve seat member 104 disposed in a valve hole 103 of the valve body 100 between the ports 101 and 102,
The valve hole 1 on the low pressure port 102 side is engaged with the valve seat member 104.
03, and a socket 105 extending into the socket 105.
The valve member 106 is slidably held by the valve member 106 and seats on the valve seat member 104, and a valve spring 107 for urging the valve member 106 against the valve seat member 104. The hydraulic relief valve is a pilot valve C disposed on the valve body 100.
By adjusting the water pressure acting on the valve spring 107 side of the valve member 106 by B, the valve member 106 is attached to and detached from the valve seat member 104, and water of a predetermined pressure is supplied to the low-pressure port 102 through the communication hole 105 a of the socket 105. Is to be spilled.

[0003]

In a conventional hydraulic relief valve, a heat treatment (carburizing treatment) is applied to a valve body and hard chrome plating is applied to a socket in order to prevent seizure. Therefore, the socket is provided separately to form the sliding surface so that the surface treatment of the sliding surface can be easily performed, and the socket is engaged with the valve seat member. Therefore, the water that has passed between the valve member and the valve seat member is discharged into a narrow space between the socket and the valve member.

The water discharged into the space is throttled between the valve member and the valve seat member, and moves from the high pressure side to the low pressure side, so that the pressure drops rapidly. Therefore, the pressure of the water drops below the saturated water vapor pressure of the water temperature, and steam bubbles are generated, and the steam bubbles collapse immediately. Since the impact due to the collapse of the vapor bubbles is generated in a narrow portion of the space, cavitation erosion (erosion) is easily generated in the socket.

It is an object of the present invention to provide a hydraulic relief valve which reduces cavitation erosion and has excellent durability.

[0006]

According to a first aspect of the present invention, there is provided a hydraulic relief valve in which a valve seat member and a socket are spaced apart such that a low pressure port is located therebetween. Is a passage communicating with the low pressure port. In particular, it is preferable that the socket be positioned as far as possible from the valve seat member so that the valve member can slide (claim 2). Further, an extension is provided in the socket, and an escape space for allowing water from the valve seat member to escape is formed between the extension and the inside of the valve body. Further, the valve seat member is arranged with a gap with respect to the valve body, and a sealing material is interposed in the gap.

[0007] The hydraulic relief valve of the second invention (Claim 5)
Is a device in which a valve seat member and a socket are spaced apart with a tubular member interposed therebetween such that the low-pressure port is located therebetween, and a communication hole communicating with the low-pressure port is formed in the tubular member.
Preferably, the cylindrical member is formed by covering with a hard material or a hard material, and the opening of the communication hole is preferably considered so that the flow rate of water from the valve seat member can be reduced. Further, the tubular member is fixed to the valve seat member, or is fitted along the inside of the valve hole of the valve body (claims 8 and 9). Further, the socket is positioned in the radial direction by the valve hole of the valve body, and is positioned in the axial direction by being sandwiched between the holding member and the step portion of the valve hole.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The hydraulic relief valve according to the first invention (claims 1 to 4) and the second invention (claims 5 to 10) will be described below with reference to FIGS. explain.

(1) The hydraulic relief valve of the first invention: First
The hydraulic relief valve according to the invention comprises a valve seat member positioned between a high-pressure port and a low-pressure port opened in a valve hole of a valve body, and a socket slidably holding the valve member seated on the valve seat member. This arrangement reduces the effects of steam bubbles generated when water passes through the valve seat member and the collapse of the steam, thereby reducing erosion of the socket.

FIG. 1 shows a hydraulic relief valve according to the first invention.
It will be described based on. 1 includes a valve body 2, a valve seat member 3, a socket 4, a valve member 5, and a valve spring 6.
And a pilot valve CB in addition to the main valve PB.

The valve body 2 of the main valve PB is composed of a cylindrical cylinder body 8 and a pressing member 9 for closing one end of the cylinder body 8 via a sealing material. Members 3 to 6 are arranged. The high pressure port 11 and the low pressure port 12 are arranged on the outer periphery of the cylinder body 8 from the holding member 9 side.
Are sequentially formed. Each port 11 and 12 has a valve hole 10
Opened inside and communicated with each other. High pressure port 1
1 is connected to the high pressure passage, and the low pressure port 12 is connected to the low pressure passage.

The valve seat member 3 is formed in an annular shape with a flange, and is inserted between the ports 11 and 12 with a gap (20 to 50 μ) into a projection 13 projecting into the valve hole 10. . A seal ring 14 made of rubber is provided on the outer periphery of the valve seat member 3, and the seal ring 14 is elastically contacted with the projection 13. The valve seat member 3 is positioned by contacting the flange 15 from the high-pressure port 11 side to the projection 13 of the valve hole 10, and is pressed by the projection 13 by the holding member 9. The holding member 9 has a communication hole 18 communicating with the high pressure port 11.
Through the communication hole 18 to allow water to flow through the valve seat member 3.
Lead inside.

The socket 4 and the valve member 5 are arranged in the valve hole 10 in the upper part of the valve seat member 3 in FIG. The socket 4 is formed in a cylindrical shape, and is mounted in the valve hole 10 with the low-pressure port 11 positioned between the valve seat member 3 and the axial direction away from the low-pressure port 11. Socket 4 is the main valve PB
Is screwed to the valve main body 25 of the pilot valve CB connected to the pilot valve CB. When the socket 4 is separated from the valve seat member 3 in this manner, a hydraulic passage S communicating with the low pressure port 12 is formed between the members 4 and 3. The socket 4 is formed with a cylindrical extension portion 19 that projects from the distal end on the valve seat member 3 side with a reduced diameter. The axial length of the inner circumference of the socket 4 including the extension 19 is a length that can slidably hold the valve member 3.
The outer circumference of the extension portion 19 has a clearance space N between the inner circumference of the valve hole 10 and the clearance N.
(Escape part). The socket 4 is SUS
630 (JIS symbol), and the entire surface is subjected to precipitation hardening treatment (heat treatment) and hard chrome plating.

The valve member 5 is slidable along the inner periphery of the socket 4 and is seated on a valve seat 20 of the valve seat member 3.
Two sliding members 21 and a sealing member 22 that are in sliding contact with the inner periphery of the socket 4 are fitted on the outer periphery of the valve member 5. The sliding member 21 is formed of a low-sliding material (a material having a low friction coefficient) such as, for example, an ultrahigh molecular weight polyester-based or polyester-based resin. A stepped passage 23 including a throttle hole 24 opening into the valve seat member 3 is formed inside the valve member 5. The stepped passage 23 extends through the valve member 5 on the pilot valve CB side and penetrates the valve member 5, and the valve member 6 is pressed against the valve seat 20 by the valve spring 6 housed in the enlarged diameter hole 26. . The valve member 5 is made of SUS630, and a hard layer is formed on the outer peripheral side by carburizing.

The valve body 25 of the pilot valve CB is formed by screwing two blocks 27 and 28 through a seal material, and the block 27 is screwed into the opening of the valve body 2 of the main valve PB. Screw-connected. A spring chamber 29 is formed inside the valve body 25, and the valve seat sheet member 30 of the pilot valve CB, the poppet valve body 31, and the valve spring 32 are arranged in the spring chamber 29. A socket 4 is screwed to a block 27 projecting into the valve hole 10 of the valve body 2, and the valve seat sheet material 30 is sandwiched between the socket 4 and the socket 4. The valve seat material 30 includes the valve member 5 and the block 2.
The eight chambers define an intermediate chamber A and a back pressure chamber B. In the block 27, a communication passage 34 which opens to the back pressure chamber B and extends from the outer periphery of the socket 4 to the low pressure port 12 is formed.

A stepped passage is formed inside the valve seat material 30 in which a throttle hole 35a opening to the intermediate chamber A and a valve seat hole 35b opening to the back pressure chamber B with an increased diameter are continuous. I have. The poppet valve element 31 is seated on the valve seat 36 of the valve seat hole 35b from the back pressure chamber B. The poppet valve element 31 is guided by sliding a shaft part 38 extending from a conical valve part 37 seated on a valve seat 36 in a valve guide member 39. A valve spring 32 is provided between the valve guide member 39 and the conical valve portion 37.
Are provided to press the poppet valve body 31 against the valve seat 36. The spring force of the valve spring 32 is adjusted by rotating the adjustment bolt 40 screwed to the tip of the block 28 and moving the guide pressing member 41 and the valve guide member 39 in the communication hole 29 forward and backward.

Next, the operation of the hydraulic relief valve 1 of the first invention will be described. For convenience of explanation, the hydraulic pressure relief valve 1 is in the state of FIG. 1, and the main valve PB and the pilot valve CP
Is closed.

The water pressure from the high pressure port 11 is introduced into the intermediate chamber A from the throttle hole 24 of the valve member 5 through the stepped passage 23. The water pressure introduced into the intermediate chamber A further acts on the poppet valve body 31 through the throttle hole 35a and the valve seat hole 35b of the valve seat material 30. When the water pressure becomes equal to or higher than a predetermined pressure, the poppet valve element 31 is separated from the valve seat 36 against the valve spring 32 by the water pressure, and the pilot valve CB
Is opened.

When the pilot valve CB is opened, the water in the intermediate chamber A is filled with the throttle hole 35a, the valve seat hole 35b, and the communication passage 3.
4 flows to the low-pressure port 12 side, the pressure in the intermediate chamber A decreases, and a pressure difference occurs between the enlarged-diameter hole 26 side of the valve member 5 and the high-pressure port 11 side. To separate from the valve seat member 3 to open the main valve PB.

When the main valve PB is opened, the high pressure port 11 and the low pressure port 12 communicate with each other via the hydraulic passage S.
Water flows from the high pressure port 11 to the low pressure port 12 through the space between the valve seat member 3 and the valve member 5.

At this time, the water passing through the gap between the valve seat member 3 and the valve body 5 is squeezed and falls to a temperature below the saturated steam pressure of the water temperature, and the water boils to generate steam bubbles and collapse immediately. Although the collapse of the vapor bubbles acts on the socket 4, the influence of the collapse of the vapor bubbles is weakened because the socket 4 is positioned axially away from the valve seat member 3.
In particular, when the socket 4 is positioned as far away from the valve seat member 3 as possible, the effect of the collapse of steam bubbles can be effectively reduced, and erosion of the socket 4 can be reduced. In addition, the valve seat member 3
The water passing between the valve member 5 and the valve member 5 escapes to the escape space N on the outer periphery, so that the flow velocity of the water directly hitting the distal end of the socket 4 becomes gentle, and erosion due to water pressure is reduced.

When the water on the high pressure port 6 side reaches a predetermined pressure,
The valve member 5 is seated on the valve seat 20 by the valve spring 6 to close the main valve PB. At this time, the valve seat member 4 is moved by the gap (20 to 50 μ) by the force from the valve member 5 so that the axes are aligned with each other, and the valve member 5 is seated in a sealed state. In addition, when the valve member 5 is attached to and detached from the valve seat 20,
The sliding resistance with the inner periphery of the socket 4 is minimized by the sliding member 21 and the sealing member 22, and the sliding is performed smoothly.

In the hydraulic relief valve 1 according to the first aspect of the present invention, the valve seat member 3 and the socket 4 are positioned so as to be separated from each other in the axial direction, and are generated by a pressure drop of water passing between the valve member 5 and the valve seat member 3. It is possible to reduce the effect of the collapse of the steam bubbles. As a result, erosion of the socket 4 can be reduced, and the durable hydraulic relief valve 1 can be provided. In particular, since the socket 4 is positioned as far as possible from the valve seat member 3 as a minimum so that the valve member 5 can be slidably held, the space of the hydraulic passage S can be enlarged, and the collapse of steam bubbles can be reduced. The effect can be minimized.

(2) The hydraulic relief valve of the second invention: the second
The hydraulic relief valve according to the invention comprises: a valve seat member positioned between a high-pressure port and a low-pressure port opened in a valve hole of a valve body;
By disposing the tubular member between the sockets that slidably hold the valve member, the effect of the collapse of the vapor bubbles generated when water passes through the valve seat member is blocked by the tubular member, Erosion is reduced.

FIG. 2 shows a hydraulic relief valve according to the second invention.
It will be described based on. 2 includes a valve body 52, a valve seat member 53, a tubular member 54, and a socket 5.
5. In addition to the main valve PB including the valve member 56 and the valve spring 57, a pilot valve CB is provided.

The valve body 52 of the main valve PB is composed of a cylindrical cylinder body 58 and a pressing member 59 for closing one end of the cylinder body 58 via a sealing material.
Each of the members 53 to 57 is arranged in 0. A high pressure port 61 is provided on the outer periphery of the cylinder body 58 from the holding member 59 side.
And a low pressure port 62 are sequentially formed. Each port 6
The reference numerals 1 and 62 open into the valve hole 60 and communicate with each other. The high pressure port 61 communicates with the high pressure passage, and the low pressure port 62 communicates with the low pressure passage.

The valve seat member 53 is formed in an annular shape with a flange, and a cylinder hole 60 is provided between each of the ports 61 and 62.
It is inserted into the protrusion 63 protruding inward with a gap (20 to 50 μ). A rubber seal ring 64 is provided on the outer periphery of the valve seat member 53, and the seal ring 64 is elastically contacted with the projection 63. Further, the valve seat member 53 is positioned by abutting the flange 65 from the high pressure port 61 side to the projection 63 of the valve hole 60. The holding member 59 has a communication hole 68 communicating with the high pressure port 61.
Water is guided through 8 into the valve seat member 53.

The valve seat member 53 has a valve hole 60 in the upper part in FIG.
The tubular member 54, the socket 55, and the valve member 56 are arranged. The cylindrical member 54 is press-fitted to the outer periphery of the valve seat member 53 protruding from the projection 63, and has a gap passage 69 between the cylindrical member 54 and the inner periphery of the valve hole 60. The tubular member 54 extends above the low-pressure port 62 and has a plurality of communication holes 70 communicating the low-pressure port 62 and the valve seat member 53.
Each communication hole 70 squeezes water from the valve seat member 53 and flows out to the low pressure port 62. The hardness of the cylindrical member 54 is increased by coating a hard material such as ceramics or stainless steel with heat treatment or hard chrome plating.

The socket 55 is formed in a cylindrical shape. The socket 55 is inserted from the opening side of the valve body 52 along the inner circumference of the cylinder hole 60, and the step 66 of the cylinder hole 60 and the cylindrical member 5 are inserted.
4. When the socket 55 is placed on the tubular member 54 in this manner, the socket 55
Are arranged at a distance from the valve seat member 53 with the valve seat member 53 and the tubular member 54 (communication hole 70) to form a hydraulic passage S communicating with the low-pressure port 62. The socket 55 protrudes from the opening side of the valve body 52 and extends into the pilot valve CB, and is positioned between the pilot valve CB and the step 66. The socket 55 is SUS6
30 and is subjected to precipitation hardening treatment (heat treatment) and hard chrome plating.

The valve member 56 is slidable along the inner periphery of the socket 55 and is seated on the valve seat 71 of the valve seat member 53. Inside the valve member 56, a stepped passage 73 including a throttle hole 72 opening into the valve seat member 53 is formed.
The stepped passage 73 is enlarged in diameter on the pilot valve CB side and penetrates, and the valve member 56 is pressed against the valve seat 71 by the valve spring 57 housed in the enlarged diameter hole 74. The valve member 56
A hard layer is formed on the outer periphery by carburizing treatment (heat treatment).

The pilot valve CB comprises a valve body 75, a valve seat material 76, a poppet valve body 77, a valve spring 78 and the like. The valve body 75 is formed by screwing a guide pressing member 80 to one end of a cylindrical cylinder body 79, and the open end of the cylinder body 79 is brought into contact with the open end of the valve body 52 with a sealing material interposed therebetween. Are connected by Valve body 75
, A spring chamber 80a (valve hole) is formed, and the valve seat sheet material 76, the poppet valve body 77, and the valve spring 78 are arranged in the spring chamber 80a.

The distal end of the socket 55 is inserted into the cylinder 79 to determine the radial position of the cylinder 79. A cylindrical holding member 8 is provided in the cylinder body 79.
1 is mounted, and the valve seat material 76 is held between the socket seat 55 and the concave portion of the socket 55. The pressing member 81 is interposed between the guide pressing member 80 and the recess of the socket 55, and presses the socket 55 against the stepped portion 66 of the valve body 52 by screwing the guide pressing member 80 to position the socket 55 in the axial direction. . The holding member 81 has a plurality of through holes 83 that open into a communication passage 82 formed on the inner periphery of the cylinder body 79. The communication passage 82 is connected to the low pressure port 62 via a gap passage 69 formed on the outer periphery of the socket.

The valve seat sheet material 76 defines an intermediate chamber A and a back pressure chamber F on the valve member 52 side and the guide pressing member 80 side. Inside the valve seat material 76, a throttle hole 84a opening to the intermediate chamber A, and a valve seat hole 8 opening to the back pressure chamber B with an increased diameter.
4b is formed. The valve seat 85 of the valve seat hole 84a is provided with a poppet valve body 77 from the back pressure chamber B.
Is sitting. The poppet valve body 77 is guided by a spring guide 88 in a pressing member 81 on a shaft portion 87 extending from a conical valve portion 86 seated on a valve seat 85. A valve spring 78 is stretched between the conical valve portion 86 and the guide member 89 in the guide holding member 80, and presses the poppet valve body 77 against the valve seat 85. The spring force of the valve spring 78 rotates the adjustment bolt 90 screwed to the tip of the guide pressing member 80,
The guide shaft 91 and the guide member 89 in the guide holding member 80
Is adjusted by moving forward and backward.

Next, the operation of the hydraulic relief valve 51 of the second invention will be described. For convenience of explanation, the hydraulic relief valve 51 is in the state shown in FIG. 1, and the main valve PB and the pilot valve CP are closed.

The water pressure from the high pressure port 61 is applied to the valve member 56.
Through the stepped passage 73 into the intermediate chamber A. The water pressure introduced into the intermediate chamber A further acts on the poppet valve body 77 through the throttle hole 84 a and the valve seat hole 84 b of the valve seat material 76. When the water pressure becomes equal to or higher than a predetermined pressure, the water pressure causes the poppet valve body 77 to separate from the valve seat 85 against the valve spring 78, and the pilot valve C
B is opened.

When the pilot valve CB is opened, the water in the back pressure chamber B flows out through the throttle hole 84a and the valve seat hole 84b to the low pressure port 62 side, and the enlarged diameter portion 74 of the valve member 56 is opened.
A pressure difference is generated between the main valve P and the high pressure port 61, and the valve member 56 separates from the valve seat member 53 against the valve spring 57, and the main valve P
B is opened.

When the main valve PB is opened, the high pressure port 61 and the low pressure port 62 communicate with each other via the hydraulic passage S.
Water flows from the high pressure port 61 to the low pressure port 62 through the space between the valve seat member 53 and the valve member 56.

At this time, the water passing through the gap between the valve seat member 53 and the valve member 56 is squeezed and dropped to a temperature below the saturated steam pressure of the water temperature, and the water boils to generate and collapse steam bubbles. Although the collapse of the vapor bubbles acts on the socket 55 and the valve body 52, the collapse of the vapor bubbles on the socket 55 and the valve body 52 is reduced by being interrupted by the tubular member 54. Further, the cylindrical member 54 directly receiving the collapse of the vapor bubbles
Is formed of a hard material and is coated with the hard material, so that the erosion is suppressed. Further, since the tubular member 54 is fixed by the valve seat member 53 and the socket 55, the tubular member 54 does not vibrate even if it receives water pressure.

The water flowing out to the hydraulic passage S is
When passing through each of the communication holes 70, the pressure is reduced and reaches the low pressure port 62 in a state where the pressure is lowered. Thus, the valve seat member 5
In the process from the gap between the valve member 3 and the valve member 56 to the low-pressure port 62, the generation of steam bubbles is suppressed by gradually reducing the pressure of water.

When the water on the high pressure port 61 side reaches a predetermined pressure, the high pressure port 61 acting on the valve member 56 and the back pressure chamber B
The valve member 56 is seated on the valve seat 71 by the valve spring 57 to open the main valve PB. At this time, the valve seat member 53 swings by the gap (20 to 50 μ) by the force from the valve member 56 so that the axes are aligned with each other, and the valve member 5 is seated in a sealed state. Further, the socket 55 includes the valve body 52, the holding member 81, and the guide holding member 80.
, The valve member 56 is seated on the valve seat 71 with the misalignment with the valve seat member 53 reduced.

In the hydraulic relief valve 51 of the second invention, the socket 55 and the valve seat member 53 are positioned axially apart from each other with the cylindrical member 54 interposed therebetween, so that the space between the valve member 56 and the valve seat member 53 is established. The effect of the collapse of the vapor bubbles generated by the pressure drop of the passing water can be blocked by the tubular member 54 and does not directly act on the valve body 52 or the socket 55. As a result, erosion of the valve body 52 and the socket 55 is reduced,
A durable hydraulic relief valve 51 can be provided. Also,
It is the cylindrical member 5 that is directly affected by the collapse of the steam bubbles.
4, the cost and workability of maintenance of the hydraulic relief valve 51 can be reduced by replacing only the tubular member 54.

The hydraulic relief valve 51 of the second invention is
Although the cylindrical member 54 is fixed so as to form the gap passage 69 between the cylindrical member 54 and the cylinder hole 60, the present invention is not limited to this. The hydraulic relief valve 51 shown in FIG. 3 has a cylindrical member 54 fitted along the inner circumference of the cylinder hole 60. With this configuration, the radial distance between the valve seat member 53 and the inner periphery of the tubular member 54 can be increased, and the valve member 56 and the valve seat member 5
3, the effect of the collapse of the vapor bubbles generated when passing through the gap with 3 can be reduced.

In the first and second aspects of the present invention, the hydraulic relief valve 1 has a structure in which the open / close valve of the main valve PB is adjusted by the pilot valve CB. However, the present invention is not limited to this. Alternatively, the invention may be applied to a direct acting type having only the main valve PB.

[0044]

In the hydraulic relief valve according to the first aspect of the present invention, the hydraulic relief valve according to the first aspect of the present invention is arranged such that the valve seat member and the socket are spaced apart such that the low pressure port is located therebetween. In addition, a passage communicating with the low pressure port is provided between these members. By arranging the valve seat member and the socket apart, the passage from the valve seat member to the low pressure port can be widened, and the distance between the valve seat member and the socket can be made longer than before. Thus, the effect of collapse of steam bubbles generated when water passes through the valve seat member can be reduced, erosion of the socket and the like can be reduced, and a hydraulic relief valve having excellent durability can be provided.

Further, the socket is positioned so as to be able to slide the valve member as far as possible from the valve seat member. Thereby, the socket can be separated from the valve seat member as much as possible, and furthermore, the influence of the collapse of the vapor bubbles can be reduced, and the erosion can be further reduced.

An escape space for allowing water from the valve seat member to escape is formed in the socket, and an extension for holding the valve body is left inside the socket. This allows the socket to slidably hold the valve element, and allows the water from the valve seat member to escape to the escape space so that the flow velocity can be moderated, and the erosion of the socket portion directly hit by water from the valve seat member is prevented. Can be reduced.

The valve seat member is disposed with a gap with respect to the valve body, and a sealing material is interposed in the gap.
Thus, when the valve member is seated on the valve seat member, the valve seat member swings by the amount of the gap, so that these axes can be aligned with each other, and the sealing property between the valve member and the valve seat member is improved. It can improve and prevent water leakage.

In the hydraulic relief valve according to the second aspect of the present invention, the valve seat member and the socket are disposed separately with a cylindrical member interposed therebetween such that the low-pressure port is located therebetween, and the cylindrical member communicates with the low-pressure port. The contact hole is formed. This allows
Water from the valve seat member is blocked by the tubular member, so that the influence of the collapse of the steam bubbles directly on the valve body and the socket is prevented, and erosion of the valve body and the socket can be reduced.

It is formed by covering a cylindrical member with a hard material or a hard material. Thus, the erosion of the tubular member that is directly subjected to the water pressure (steam bubbles or collapse) from the valve seat member can be suppressed.

The opening of the communication hole is designed to reduce the flow rate of water from the valve seat member. This makes it possible to gradually reduce the pressure of water from the high-pressure port to the low-pressure port through the gap between the valve seat member and the valve member and through the communication hole of the cylindrical member, thereby suppressing the generation of steam bubbles and breaking Food can be reduced.

A cylindrical member is fixed to a valve seat member. Thus, the cylindrical member that directly receives the water pressure from the valve seat member can be securely fixed without vibrating.

The tubular member is fitted along the inside of the valve hole of the valve body. Thereby, since the interval between the inner periphery of the cylindrical member and the valve seat member can be widened, the influence of the collapse of steam bubbles generated when passing through the valve seat member is reduced,
Erosion can be reduced.

The socket is positioned in the radial direction by the valve hole of the valve body, and is positioned in the axial direction by being sandwiched between the pressing member and the step portion of the valve hole. Thus, the socket can be reliably positioned in the radial direction and the axial direction and disposed in the valve body, so that the misalignment between the sliding valve member and the valve seat member can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a hydraulic relief valve according to a first invention.

FIG. 2 is a sectional view showing a configuration of a hydraulic relief valve according to a second invention.

FIG. 3 is a sectional view showing a modification of the hydraulic relief valve of the second invention.

FIG. 4 is a sectional view showing a configuration of a conventional hydraulic relief valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic relief valve 2 Valve body 3 Valve seat member 4 Socket 5 Valve member 6 Valve spring 10 Valve hole 11 High pressure port 12 Low pressure port 14 Seal ring 19 Extension part 51 Hydraulic relief valve 52 Valve body 53 Valve seat member 54 Cylindrical member 55 Socket 56 valve member 57 valve spring 61 high pressure port 62 low pressure port 66 step 70 communication hole 81 holding member N escape space S hydraulic passage

Claims (10)

[Claims] A valve body having a valve hole in which a high pressure port and a low pressure port open; a valve seat member located between the high pressure port and the low pressure port and disposed in the valve hole;
A valve member disposed in the valve hole and seated on the valve seat member from the low pressure port side, a socket disposed along the valve hole and slidably holding the valve member, and the valve member. In a hydraulic relief valve including a valve spring that biases the valve seat member, the valve seat member and the socket are disposed separately so that the low-pressure port is located therebetween, and the valve seat member and A hydraulic relief valve, wherein a passage communicating with the low pressure port is provided between the sockets. 2. The hydraulic relief valve according to claim 1, wherein the socket is positioned at a maximum distance from the valve seat member to allow the valve member to slide. 3. The system according to claim 1, wherein the socket has an extension protruding toward the valve seat member, and an escape space for allowing water from the valve seat member to escape is formed between the extension and the inside of the valve body. The hydraulic relief valve according to claim 1 or 2, wherein 4. The valve seat member is disposed with a gap in the valve body, and a seal member that elastically contacts the valve seat member and the inside of the valve body is interposed in the gap. The hydraulic relief valve according to any one of claims 1 to 3, wherein 5. A valve body having a valve hole in which a high pressure port and a low pressure port open, a valve seat member located between the high pressure port and the low pressure port and disposed in the valve hole,
A valve member disposed in the valve hole and seated on the valve seat member from the low pressure port side, a socket disposed along the valve hole and slidably holding the valve member, and the valve member. A hydraulic relief valve including a valve spring biasing the valve seat member, wherein the valve seat member and the socket are interposed with a tubular member such that the low-pressure port is located therebetween; A hydraulic relief valve, wherein a communication hole communicating with the low pressure port is formed in the member. 6. The tubular member is formed of a hard material,
The hydraulic relief valve according to claim 5, wherein the hydraulic relief valve is coated with a hard material. 7. The hydraulic relief valve according to claim 5, wherein the communication hole of the cylindrical member restricts a flow rate of water from the valve seat member and causes the water to flow out to the low-pressure port. . 8. The hydraulic relief valve according to claim 5, wherein the tubular member is fixed to the valve seat member. 9. The valve according to claim 5, wherein the tubular member is fitted along the inside of the valve hole of the valve body.
The hydraulic relief valve according to claim 7. 10. The socket, which is fitted along the inside of the valve hole of the valve body and is positioned in the radial direction, and is integrated with the step portion of the valve hole and the cylindrical member and the valve body. The hydraulic relief valve according to any one of claims 5 to 9, wherein the hydraulic relief valve is sandwiched between members and positioned in an axial direction.