Valves and Hydraulic Systems

Abstract

To provide a valve which enables improvement of override characteristics and downsizing of a device configuration, and to provide a construction machine.SOLUTION: A valve includes: a housing 201 having a valve chamber; and a valve body 210 which is movably housed in the valve chamber T, and has a pressure receiving part 211, on which a force generated by a pressure of a working fluid acts, at one end side. A diameter of the pressure receiving part is larger than a diameter of a high pressure port 202 leading to the valve chamber. The valve body 210 includes a corner part 213 formed along an outer periphery of the pressure receiving surface. The corner part may contact with the inner wall side of the high pressure port of the valve chamber.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to valves and hydraulic systems that provide improved override performance. [Background technology]

[0002] Many construction machines have hydraulic circuits and are hydraulically driven. The hydraulic circuits are equipped with relief valves that release pressure when the pressure in the hydraulic oil flow path exceeds a predetermined value. The relief valve includes a valve element that opens and closes the flow path and a housing that movably accommodates the valve element. Conventional relief valves, for example, have a cylindrical valve element with a closed seat surface formed on one end of the valve element.

[0003] The corners of the seat surface are tapered. On the housing side, a tapered surface is formed on the valve seat where the corners of the seat surface come into contact, and when the valve disc is in contact with the valve seat side, the valve disc and the valve seat come into close contact, blocking the relief flow path for relief. The hydraulic oil presses against the seat surface of the valve disc due to the pressure in the flow path. When a pressure greater than a predetermined level is applied to the valve disc, the hydraulic oil presses against the seat surface, causing the valve disc to move (override), opening the relief flow path, and the hydraulic oil flows into the relief flow path, releasing the pressure in the flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-63261 Summary of the Invention [Problem to be solved by the invention]

[0005] 7, in a conventional relief valve 300, a tapered surface 315 is formed at a corner 313 of a valve element 310. In the conventional relief valve 300, a pressure-receiving surface 311 that receives the fluid force of the hydraulic oil is formed to be smaller in diameter than the high-pressure port 302. The pressure-receiving surface 311 of the valve element 310 is formed so as to be inserted into the high-pressure port 302 and to come into contact with the tapered surface 315 formed at the corner 313 of the pressure-receiving surface 311 and the rear end portion 302A of the high-pressure port 302.

[0006] As shown in Figure 8(A), when comparing the valve disc 310 before and after movement, the pressure-receiving area of ​​the valve disc 310 before movement is an area corresponding to the diameter of the high-pressure port 302. As shown in Figure 8(B), when the valve disc 310 moves, the hydraulic oil flows into the valve chamber T from the gap that forms between the valve disc 310 and the high-pressure port. As a result, the pressure-receiving area after the valve disc 310 moves becomes the area of ​​the pressure-receiving surface 311, which is smaller than the diameter of the high-pressure port 302. Therefore, the force applied to the valve disc 310 decreases from the value obtained by multiplying the pressure of the hydraulic oil by the area of ​​the high-pressure port to the value obtained by multiplying the pressure of the hydraulic oil by the area of ​​the pressure-receiving surface 311.

[0007] As described above, conventional relief valves have room for improvement because the primary pressure-receiving diameter applied to the seat surface decreases as the valve disc travel increases. Improving the override characteristics of a relief valve also improves the work capacity of construction machinery. The inventors have conducted extensive research to reduce the size of the device while improving the override characteristics of the relief valve.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a valve and a fluid pressure system that can improve override characteristics and reduce the size of the device configuration. [Means for solving the problem]

[0009] A valve according to one aspect of the present invention comprises a housing having a valve chamber, and a valve body accommodated in the valve chamber and having a pressure-receiving surface at one end thereof on which a force generated by the pressure of a working fluid acts, the diameter of the pressure-receiving surface being larger than the diameter of a high-pressure port communicating with the valve chamber, the pressure-receiving surface having a corner formed along the outer periphery thereof, the corner being capable of contacting the inner wall side of the high-pressure port of the valve chamber.

[0010] A valve according to one aspect of the present invention comprises a housing having a valve chamber communicating with a high-pressure port, and a valve body accommodated in the valve chamber and having a pressure-receiving surface at one end thereof on which a force generated by the pressure of a working fluid acts, the valve body having a corner formed along the outer periphery of the pressure-receiving surface that can come into contact with the housing.

[0011] A valve according to one aspect of the present invention comprises a housing having a valve chamber communicating with a high-pressure port, and a valve body accommodated in the valve chamber to open and close the high-pressure port, the valve body having a pressure-receiving surface on one end of which a force generated by the pressure of a working fluid acts when the high-pressure port is opened, the diameter of the pressure-receiving surface being larger than the diameter of the high-pressure port.

[0012] By configuring the valve body in this manner, when the pressure-receiving surface of the valve body is moved by the fluid force of the working fluid flowing in from the high-pressure port, the fluid force of the working fluid acting on the valve body before and after movement acts on the area of ​​the pressure-receiving surface and remains constant, thereby improving the override characteristics of the valve body.

[0013] The corner may be formed so as to come into contact with a tapered surface formed at the opening of the high-pressure port.

[0014] With this configuration, when the valve body is pressed against the high-pressure port, the corners come into contact with the tapered surface and adhere tightly, thereby improving the sealing performance of the high-pressure port.

[0015] The valve body may have a slide surface that slides relative to the housing, and the pressure-receiving surface may be formed with a diameter smaller than the diameter of the slide surface.

[0016] By configuring it in this manner, even if working fluid leaks between the slide surface and the housing and there is working fluid leaking from the high-pressure port to the low-pressure port, the force applied to the valve body caused by the pressure of the working fluid can be adjusted by making the diameter of the pressure-receiving surface smaller than the diameter of the slide surface, and the valve body can be prevented from moving when the pressure of the working fluid is smaller than a predetermined value.

[0017] The pressure-receiving surface may be configured to have a step or a tapered surface formed between the pressure-receiving surface and the sliding surface.

[0018] With this configuration, it is possible to prevent the valve element from moving when the pressure of the working fluid is smaller than a predetermined value.

[0019] The valve element may be configured to have the slide surface formed to have substantially the same diameter as a cylinder formed in the valve chamber.

[0020] With this configuration, it is possible to prevent the working fluid from leaking from between the slide surface and the cylinder depending on the properties of the working fluid.

[0021] The valve may be configured to include a return spring that presses the valve element toward the high-pressure port.

[0022] With this configuration, the valve element is pressed toward the high-pressure port by the return spring, and the corner portion comes into contact with the tapered surface for tight sealing, thereby improving the sealing performance of the high-pressure port.

[0023] a valve according to one aspect of the present invention comprising: a housing having a valve chamber; and a valve disc movably accommodated in the valve chamber, the valve disc having a pressure surface at one end thereof on which a force generated by the pressure of a working fluid acts, the pressure surface having a diameter larger than the diameter of a high-pressure port communicating with the valve chamber, the pressure surface having a corner formed along the outer periphery thereof, the corner being able to contact an inner wall of the valve chamber on which an opening of the high-pressure port is formed, the corner being formed so as to contact a tapered surface formed at the opening of the high-pressure port, the valve disc having a sliding surface that slides relative to the housing, the pressure surface having a diameter smaller than the diameter of the sliding surface, the valve disc having a step or tapered surface formed between the pressure surface and the sliding surface, the valve disc having the sliding surface formed to have approximately the same diameter as a cylinder formed in the valve chamber, and a return spring that presses the valve disc in the direction of the high-pressure port.

[0024] A valve according to one aspect of the present invention comprises a housing having a valve chamber, and a valve disc that is movably accommodated in the valve chamber and has a pressure-receiving surface at one end thereof on which a force generated by the pressure of a working fluid acts, the valve disc having a corner formed along the outer periphery of the pressure-receiving surface and capable of contacting the housing, the corner being formed so as to contact a tapered surface formed at an opening of a high-pressure port communicating with the valve chamber, the valve disc having a sliding surface that slides relative to the housing, the diameter of the pressure-receiving surface being smaller than the diameter of the sliding surface, a step or tapered surface formed between the pressure-receiving surface and the sliding surface, the valve disc having the sliding surface that is formed to have approximately the same diameter as a cylinder formed in the valve chamber, and a return spring that presses the valve disc toward the high-pressure port.

[0025] a valve according to one aspect of the present invention comprising: a housing having a valve chamber communicating with a high-pressure port; and a valve disc movably accommodated in the valve chamber to open and close the high-pressure port, the valve disc having a pressure-receiving surface on one end of which a force generated by the pressure of a working fluid acts when the high-pressure port is opened, the pressure-receiving surface having a diameter larger than the diameter of the high-pressure port, the valve disc having a corner that can come into contact with the housing so as to come into contact with a tapered surface formed at an opening of the high-pressure port, the valve disc having a sliding surface that slides relative to the housing, the pressure-receiving surface having a diameter smaller than the diameter of the sliding surface, the valve disc having a step or tapered surface formed between the pressure-receiving surface and the sliding surface, the valve disc having the sliding surface that is formed to have approximately the same diameter as a cylinder formed in the valve chamber, and a return spring that presses the valve disc toward the high-pressure port.

[0026] a valve according to one aspect of the present invention comprising: a housing having a valve chamber; and a valve disc movably accommodated in the valve chamber, the valve disc having an end face at one end thereof on which a force generated by the pressure of a working fluid acts, the end face having a diameter larger than the diameter of a high-pressure port communicating with the valve chamber, the end face having a corner formed along the outer periphery of the end face, the corner being able to contact an inner wall of the high-pressure port in the valve chamber, the corner being formed so as to contact a tapered surface formed at an opening of the high-pressure port, the valve disc having a sliding surface that slides relative to the housing, the end face having a diameter smaller than the diameter of the sliding surface, the valve disc having a step or tapered surface formed between the end face and the sliding surface, the valve disc having the sliding surface formed to have approximately the same diameter as a cylinder formed in the valve chamber, and a return spring that presses the valve disc in the direction of the high-pressure port.

[0027] A fluid pressure system according to one aspect of the present invention comprises a fluid pressure pump that generates fluid pressure using a working fluid, a fluid pressure valve device that switches the output destination of the working fluid, an actuator that is driven by the working fluid supplied from the fluid pressure valve device, a housing having a valve chamber, and a valve that adjusts the pressure of the working fluid, the valve body being accommodated in the valve chamber and having a pressure-receiving surface at one end on which a force generated by the pressure of the working fluid acts, the pressure-receiving surface having a diameter larger than the diameter of a high-pressure port communicating with the valve chamber and having a corner formed along the outer periphery of the pressure-receiving surface, the corner being able to come into contact with an inner wall side of the valve chamber in which an opening of the high-pressure port is formed.

[0028] With this configuration, the override characteristics of the valve of the fluid pressure system can be improved and the device can be made smaller. [Effects of the Invention]

[0029] According to the present invention, the override characteristics of the valve can be improved and the device configuration can be made compact. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a diagram showing a configuration of a construction machine according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing the configuration of a hydraulic system applied to a construction machine according to an embodiment of the present invention. [Figure 3] 1 is a diagram showing the configuration of a relief valve applied to a construction machine according to an embodiment of the present invention. [Figure 4] 5A and 5B are diagrams illustrating the movement amount of a valve body of a relief valve according to an embodiment of the present invention. [Figure 5] 5A and 5B are diagrams showing the fluid force of hydraulic oil acting on a valve element of the relief valve according to the embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the configuration of a relief valve according to a modified example of the embodiment of the present invention. [Figure 7] FIG. 4 is a diagram showing the configuration of a relief valve according to a comparative example. [Figure 8] FIG. 6 is a diagram showing the operation of a relief valve according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, an embodiment of the present invention will be described with reference to the drawings.

[0032] (Construction machinery) As shown in Fig. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving unit 101 and a running unit 102. The revolving unit 101 is provided on the running unit 102 so as to be able to freely rotate. The revolving unit 101 is provided with a hydraulic system 1. In this embodiment, hydraulic pressure is used as an example of fluid pressure, but the working fluid may be other fluids as well as hydraulic oil.

[0033] The rotating body 101 includes a cab 103 on which an operator can ride, a boom 104 having one end swingably connected to the cab 103, an arm 105 having one end swingably connected to the other end (tip) of the boom 104 opposite the cab 103, and a bucket 106 swingably connected to the other end (tip) of the arm 105 opposite the boom 104. A hydraulic system 1 is provided inside the cab 103. The cab 103, the boom 104, the arm 105, and the bucket 106 are driven by hydraulic oil supplied from this hydraulic system 1.

[0034] (Hydraulic system) 2, the hydraulic system 1 (fluid pressure system) includes an engine 120 as a drive source, a hydraulic pump 130 (fluid pressure pump) driven by the engine 120, a plurality of actuators 140 that operate various parts of the construction machine 100, a hydraulic valve device 150 (fluid pressure valve device) that switches the operation of the plurality of actuators 140, a tank 160 that stores hydraulic oil, and a relief valve 200 (valve) for adjusting pressure. In this embodiment, the hydraulic system 1 is illustrated as being applied to a construction machine, but is not limited to this and may also be applied to other fluid pressure devices such as a hydraulic press.

[0035] The engine 120 is an internal combustion engine that uses gasoline or diesel fuel. The engine 120 has an output shaft 121, which is coupled to a hydraulic pump 130. A pipe Q is connected to the hydraulic pump 130. The hydraulic pump 130 is driven by the output shaft 121 to circulate hydraulic oil through the pipe Q, thereby generating fluid pressure. A hydraulic valve device 150 is connected to the pipe Q.

[0036] The hydraulic valve device 150 switches the output destination of the hydraulic fluid. A plurality of actuators 140 are connected to the hydraulic valve device 150 via a branched pipe Q. A plurality of hydraulic valve devices 150 are provided, and the hydraulic pressure of the hydraulic oil circulating in the pipe Q is switched using a plurality of valves to supply the hydraulic oil to the plurality of actuators 140. The plurality of actuators 140 drive the cab 103, boom 104, arm 105, bucket 106, etc. In addition, a relief valve 200 is provided in the hydraulic circuit of the hydraulic system 1 as appropriate to release pressure when the pressure in the flow path exceeds a predetermined value.

[0037] As shown in FIG. 3, the relief valve 200 includes a cylindrical housing 201, a valve element 210 housed in the housing 201 so as to be able to move freely, and a return spring 220 that presses the valve element 210.

[0038] The housing 201 is a housing that is fixed to a fixed object such as a construction machine. The housing 201 has a high-pressure port 202 connected to the high-pressure side of a hydraulic circuit, and a low-pressure port 205 connected to the low-pressure side of the hydraulic circuit. The high-pressure port 202 is formed in a circular opening hole formed on one end side of the housing 201. The high-pressure port 202 is formed along the axis L of the housing 201. Hydraulic oil flows on the inner wall side of the high-pressure port 202.

[0039] A tapered surface 202A (valve seat) is formed at the opening of the rear end of high-pressure port 202 so that the diameter of the opening increases toward the rear end in a cross-sectional view to become larger than the diameter of high-pressure port 202. Here, the rear end of high-pressure port 202 refers to the end in the direction toward the interior of housing 201 along axis L.

[0040] A corner 213 comes into contact with the tapered surface 202A at a position slightly closer to the high-pressure port 202 than the rear end 202B (end) thereof. The diameter of the rear end (maximum diameter portion) of the tapered surface 202A is formed to be slightly larger than the diameter of a corner 213 of the valve body 210, which will be described later. That is, the diameter of the corner 213 is formed to be slightly smaller than the diameter of the rear end 202B of the tapered surface 202A. A low-pressure port 205 is formed in communication with the high-pressure port 202. The low-pressure port 205 is formed in a direction perpendicular to the high-pressure port 202. The low-pressure port 205 is formed as a circular through-hole. The arrangement of the high-pressure port 202 and the low-pressure port 205 is not limited to this, and they may be arranged in the direction of the axis L.

[0041] A cylinder 203 communicating with the high-pressure port 202 is formed along the axis L within the housing 201. The cylinder 203 is formed as a circular hole. A valve element 210 is inserted into the cylinder 203 so as to be slidable along the direction of the axis L. A valve chest T is formed in the space between a front edge 203A of the cylinder 203 and the rear end of the tapered surface 202A. The high-pressure port 202 is in communication with the valve chest T.

[0042] The valve element 210 is a piston formed in a cylindrical shape. The valve element 210 opens and closes the high-pressure port 202. For example, the rear side of the cylinder 203 is formed separately, and the valve element 210 is inserted from the rear side of the cylinder 203. The valve element 210 may also be inserted from the front side of the cylinder 203, and the high-pressure port 202 may be formed separately.

[0043] The valve element 210 is closed on the high-pressure port 202 side, and has a pressure-receiving surface 211 (end surface). The center of the pressure-receiving surface 211 has a valve orifice 212 formed in a through-hole. A corner 213 is formed around the periphery of the pressure-receiving surface 211. The corner 213 is formed along the outer periphery of the pressure-receiving surface 211 so that it is larger than the diameter of the high-pressure port 202. When the high-pressure port 202 is closed, a force generated by the static pressure of the hydraulic oil acts on one end of the pressure-receiving surface 211, and when the high-pressure port 202 is open, a force generated by the dynamic pressure of the hydraulic oil acts on one end of the pressure-receiving surface 211.

[0044] Corner 213 is formed so that the side surface and pressure-receiving surface 211 form a substantially right angle when valve element 210 is viewed in cross section. Corner 213 may be processed to have an R-chamfer or a C-chamfer. The diameter of pressure-receiving surface 211 is formed to have a diameter φ2 that is larger than diameter φ3 of high-pressure port 202 and slightly smaller than rear end 202B of tapered surface 202A. On the side surface of valve element 210, diameter φ1 of sliding surface 217 with cylinder 203 is formed to have a substantially identical diameter that is slightly smaller than the diameter of cylinder 203. Sliding surface 217 slides relative to cylinder 203.

[0045] 4, when the corner 213 is configured to contact the tapered surface 202A midway, that is, when the corner 213 is configured to contact the inner wall of the high-pressure port 202 of the valve chest T and close the opening, the width of the opening communicating with the valve chest T with the same amount of movement of the valve disc 210 is smaller than when the corner 213 of the relief valve 200 is configured to contact the vicinity of the rear end 202B of the tapered surface 202A. In this way, by configuring the corner 213 to be able to contact the vicinity of the rear end 202B of the tapered surface 202A, the relief valve 200 can increase the width of the opening communicating with the valve chest T with a small amount of movement of the valve disc 210.

[0046] Returning to Figure 3, a step 216 is formed on the side surface of the valve body 210 so that the diameter of the slide surface 217 decreases. The step 216 may be a tapered surface formed so that the diameter decreases from the slide surface 217 toward the corner 213. The step 216 does not necessarily have to be formed.

[0047] The step 216 is provided so that when a large amount of hydraulic oil leaks from the slide surface 217, the flow rate of hydraulic oil flowing into the valve orifice 212 increases, causing the leaked hydraulic oil to escape to the low-pressure port 205, preventing the valve body 210 from moving when a pressure lower than the preset hydraulic oil pressure acts on the valve body 210.

[0048] A return spring 220 is provided inside the valve element 210 (opposite the pressure-receiving surface 211). The return spring 220 presses the valve element 210 toward the high-pressure port 202. As the return spring 220 presses the valve element 210 toward the high-pressure port 202, the corner 213 of the valve element 210 comes into contact with a tapered surface 202A formed on the high-pressure port 202. The spring rate of the return spring 220 is set so that the valve element 210 moves when the hydraulic oil reaches a predetermined pressure.

[0049] Next, the operation of the relief valve 200 will be described.

[0050] When the hydraulic pressure of the hydraulic oil is below a predetermined value, pressure-receiving surface 211 comes into close contact with the vicinity of rear end 202B of tapered surface 202A of high-pressure port 202. In this state, valve element 210 prevents hydraulic oil from flowing from high-pressure port 202 to low-pressure port 205. At this time, a force obtained by multiplying the pressure of the hydraulic oil by the area of ​​pressure-receiving surface 211 acts on valve element 210 in the direction opposite to the pressing direction of return spring 220.

[0051] As shown in Figure 5, when the oil pressure of the hydraulic oil G is equal to or higher than a predetermined value, a force F, which is calculated by multiplying the pressure of the hydraulic oil G by the area of ​​the pressure-receiving surface 211, acts on the valve element 210 in a direction opposite to the pressing direction of the return spring 220. This causes the return spring 220 to compress, and the valve element 210 to move along the axis L (see Figure 3) away from the high-pressure port 202. The hydraulic oil G flows into the valve chest T through a gap formed between the tapered surface 202A and the corner 213, and then into the low-pressure port 205.

[0052] At this time, the hydraulic oil G flows with inertial force, and the flow direction of the hydraulic oil G that collides with the pressure-receiving surface 211 is bent at a substantially right angle toward the corner 213 of the valve body 210, and the hydraulic oil G flows radially toward the pressure-receiving surface 211. Therefore, the area of ​​the pressure-receiving surface 211 becomes the pressure-receiving area for the fluid force of the hydraulic oil G acting on the valve body 210. When the valve body 210 moves, part of the hydraulic oil G that has accumulated inside the valve body 210 is discharged from the valve orifice 212 (see FIG. 3).

[0053] As hydraulic oil G continues to flow into the low-pressure port 205, the pressure of the hydraulic oil drops below a predetermined value. As a result, the pressing force of the return spring 220 becomes greater than the fluid force of the hydraulic oil acting on the pressure-receiving surface 211, and the valve element 210 is pressed by the return spring 220 to move to its original position, with the corner 213 coming into contact with the tapered surface 202A. While the valve element 210 is moving, negative pressure is generated inside the valve element 210, and hydraulic oil G flows in through the valve orifice 212 (see FIG. 3).

[0054] According to the relief valve 200, the area of ​​the pressure-receiving surface 211 becomes the pressure-receiving area for the fluid force of the hydraulic oil acting on the valve element 210, and even if the valve element 210 moves, the pressure-receiving area can be kept constant and a large fluid force of the hydraulic oil can be received, thereby improving the override characteristics of the valve element 210. Furthermore, according to the relief valve 200, the configuration can be simplified, thereby making it possible to make the device more compact.

[0055] [Variations] 6, tapered surface 202A does not have to be formed at the rear end of high-pressure port 202. For example, corner 202C perpendicular to axis L may be formed at the rear end of high-pressure port 202 so that a region of a predetermined width overlaps from corner 213 toward the center on pressure-receiving surface 211 of valve body 210.

[0056] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0057] 1...hydraulic system, 100...construction machine, 101...swivel body, 102...traveling body, 103...cab, 104...boom, 105...arm, 106...bucket, 120...engine, 121...output shaft, 130...hydraulic pump, 140...actuator, 150...hydraulic valve device, 160...tank, 200...relief valve (valve), 201...housing, 202...high-pressure port, 202A...tapered surface, 202B...rear end, 202C...corner, 203...cylinder, 203A...leading edge, 205...low-pressure port, 210...valve body, 211...pressure-receiving surface (end face), 212...valve orifice, 213...corner, 216...step, 217...slide surface, 220...return spring

Claims

1. a housing having a valve chamber; a valve element accommodated in the valve chamber, having a pressure-receiving surface at one end thereof on which a force generated by the pressure of the working fluid acts, the diameter of the pressure-receiving surface being larger than the diameter of a high-pressure port communicating with the valve chamber, and having a corner formed along the outer periphery of the pressure-receiving surface, the corner being capable of contacting an inner wall side of the valve chamber on which an opening of the high-pressure port is formed; Equipped with the valve body has a slide surface that slides relative to the housing, the diameter of the pressure-receiving surface is smaller than the diameter of the slide surface, and a step is formed between the pressure-receiving surface and the slide surface, the pressure-receiving surface faces a direction perpendicular to the axial direction of the high-pressure port, a valve orifice penetrating the valve body in the axial direction is formed on the pressure-receiving surface; a low-pressure port connected to a low-pressure side of a hydraulic circuit is formed in a portion of the housing corresponding to the step; a recessed portion communicating with the low-pressure port and having an opening width larger than an opening width of the low-pressure port is formed on an inner circumferential surface of the housing at a location corresponding to the step, the recessed portion forming the valve chamber, a valve seat is formed on the housing, on the low-pressure port side of the inner wall side on which the opening of the high-pressure port is formed, such that the diameter of the opening increases to be larger than the diameter of the high-pressure port toward the low-pressure port side; the corner portion of the valve body contacts the vicinity of the end portion of the valve seat on the low-pressure port side, when the corner portion is in contact with the valve seat, the step is located on a side opposite to the high-pressure port from the axial center of the low-pressure port. valve.

2. The valve body has a slide surface formed to have substantially the same diameter as a cylinder formed in the valve chamber.

10. The valve of claim 1.

3. 3. The valve according to claim 1, further comprising a return spring that urges the valve element toward the high-pressure port.

4. a fluid pressure pump that generates fluid pressure using a working fluid; a fluid pressure valve device that switches the output destination of the working fluid; an actuator driven by the working fluid supplied from the fluid pressure valve device; a valve for adjusting the pressure of the working fluid; Equipped with The valve is a housing having a valve chamber; a valve element accommodated in the valve chamber, having a pressure-receiving surface at one end thereof on which a force generated by the pressure of the working fluid acts, the diameter of the pressure-receiving surface being larger than the diameter of a high-pressure port communicating with the valve chamber, the pressure-receiving surface having a corner formed along the outer periphery thereof, the corner being capable of contacting an inner wall side of the valve chamber on which an opening of the high-pressure port is formed; Equipped with the valve body has a slide surface that slides relative to the housing, the diameter of the pressure-receiving surface is smaller than the diameter of the slide surface, and a step is formed between the pressure-receiving surface and the slide surface, the pressure-receiving surface faces a direction perpendicular to the axial direction of the high-pressure port, a valve orifice penetrating the valve body in the axial direction is formed on the pressure-receiving surface; a low-pressure port connected to a low-pressure side of a hydraulic circuit is formed in a portion of the housing corresponding to the step; a recessed portion communicating with the low-pressure port and having an opening width larger than an opening width of the low-pressure port is formed on an inner circumferential surface of the housing at a location corresponding to the step, the recessed portion forming the valve chamber, a valve seat is formed on the housing, on the low-pressure port side of the inner wall side on which the opening of the high-pressure port is formed, such that the diameter of the opening increases to be larger than the diameter of the high-pressure port toward the low-pressure port side; the corner portion of the valve body contacts the vicinity of the end portion of the valve seat on the low-pressure port side, when the corner portion is in contact with the valve seat, the step is located on a side opposite to the high-pressure port from the axial center of the low-pressure port. Fluid pressure systems.

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