Electronically-controlled regulator

Abstract

To enable an electronically-controlled regulator to prevent the occurrence of slow leakage via a pressure regulation valve even in a valve closed state where electric power supply to an electric motor is stopped.SOLUTION: An electronically-controlled regulator 1A has a pressure regulation valve 20A, which comprises: a valve shaft 21A that has a valve element 22 and can reciprocate in an axial direction; a valve seat 23 having a seat face 24 with which the valve element 22 closely contact on a high-pressure fluid chamber 2A side; and discharge pressure regulation means for regulating a fluid pressure for causing the valve shaft 21A to be reciprocate by an electric motor 30. The electronically-controlled regulator depressurizes and regulates an introduced high-pressure fluid by the pressure regulation valve 20A, and discharges the same in a discharge pressure chamber 3A as the fluid depressurized to a set pressure. In the electronically-controlled regulator, a cylindrical space 36A is formed on the discharge pressure chamber 3A side, and a piston 37A receiving a pressure in the discharge pressure chamber 3A is fixed to the valve shaft 21A and is slidable in the space 36A. The fluid pressure received by the piston 37A is converted into a pressure load for pressing the valve element 22 to the seat face 24 at the time of valve closing when the electric motor 30 is stopped.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a regulator that discharges high-pressure fluid such as gas fuel while reducing and regulating the pressure to a predetermined level, and more particularly to an electronically controlled regulator that electronically adjusts the pressure of the discharged fluid. [Background technology]

[0002] Regulators that reduce high-pressure fluid to a predetermined pressure and deliver it are well known, for example, regulators for gas fuels described in Japanese Patent No. 3594507 (Patent Document 1) and Japanese Patent Laid-Open No. 2011-256759 (Patent Document 2). This regulator is equipped with a valve stem that is coaxial with a valve body and a donut-shaped seat portion with a valve hole passing through the center and a seat surface with which the valve body is in close contact, and is structured such that high-pressure fluid such as CNG flowing in from an inlet of a body is biased by a pressure adjustment spring so that when the valve body is in an open state, the valve stem that is arranged to be able to slide back and forth in the axial direction with the valve body is pressed against the seat surface with a predetermined pressure, and the high-pressure gas fuel is discharged while being reduced and adjusted to the predetermined pressure.

[0003] However, in such a conventional regulator pressure reduction structure, the discharge pressure of the fluid by the regulator mechanically depends on the load of the pressure regulating spring, so it is necessary to prepare a pressure regulating spring in advance for each specified discharge pressure. Also, in a regulator used in a vehicle fuel supply system, the pressure regulating spring is fixed in advance to a specified set height, so when the engine required flow rate is high, the pressure drop becomes large, and when the required flow rate is low, the pressure drop becomes small, so there is a problem that the discharge pressure range and flow rate range are mechanically limited.

[0004] On the other hand, in an LPG regulator having a primary diaphragm chamber and a secondary diaphragm chamber, Japanese Utility Model Publication No. 59-160842 (Patent Document 3) is proposed a pressure regulating mechanism equipped with a stepping motor that is pulse-controlled in response to an output signal from a pressure sensor provided in the primary diaphragm chamber as a force adjusting means for adjusting the force of a pressure regulating spring in the primary diaphragm chamber.

[0005] In this way, the pressure regulating mechanism equipped with an electronically controlled stepping motor weakens the biasing force of the pressure regulating spring when the pressure in the primary diaphragm chamber becomes higher than a preset pressure, and strengthens the biasing force of the pressure regulating spring when the pressure in the primary diaphragm chamber becomes lower than the preset pressure, making it possible to maintain the pressure in the primary diaphragm chamber at the desired pressure.

[0006] However, with this regulator, it is only the interior of the primary diaphragm chamber that can be adjusted to and maintained at the desired pressure; the pressure of the fuel discharged from the secondary diaphragm chamber depends on the pressure regulating spring disposed within that chamber. As a result, it remains difficult to set a variety of discharge pressures with a single type of regulator, and the problem that the discharge pressure range and flow rate range are mechanically limited remains unresolved.

[0007] Therefore, the inventors and applicants of the present application previously proposed in Japanese Patent Application No. 2022-088066 (Patent Document 4) a regulator with electronic control of an electric motor as shown in Fig. 6. This electronically controlled regulator 1C is provided with a cylindrical body 10C, a high-pressure fluid chamber 2C constituting from the inlet of a fluid inlet passage 11 that introduces high-pressure fluid to the valve portion of a pressure regulating valve 20C, a discharge pressure chamber 3C constituting from the valve portion to the outlet of a fluid delivery passage 12 that discharges reduced-pressure fluid, and a pressure adjustment unit 4C as a discharge pressure adjustment means that reduces and adjusts the pressure of the discharged fluid to a predetermined pressure while operating the pressure regulating valve 20C.

[0008] The discharge pressure adjustment means constitutes a valve shaft moving structure which is actuated by the drive of an electric motor 30 to move a valve shaft 21C having a spring 25 at its tip end, thereby changing the distance between the valve body 22 and the valve seat 23. The valve shaft moving structure is operated by the electric motor 30 based on the value of a pressure sensor which detects the pressure of the reduced pressure fluid, and the pressure regulating valve 20C is opened and closed so that the pressure of the reduced pressure fluid maintains the set pressure.

[0009] In this way, rather than adjusting the discharge pressure only by the spring 25 arranged on the tip side of the valve shaft 21C, a method is adopted in which the electric motor 30 is driven and controlled based on the discharge pressure detected by a sensor while the valve element 22 provided on the valve shaft 21C is opened and closed to maintain the set discharge pressure, thereby making it possible to automatically maintain various set discharge pressures while flexibly responding to fluctuations in the required flow rate.

[0010] However, in such an electronically controlled regulator 1C, when the power supply to the electric motor 30 is stopped and the valve is closed, for example when the engine is stopped, the load that operates the valve element 22 in the closing direction is only the biasing force of the spring 25 provided on the valve shaft 21C, and the pressing force against the seat surface 24 of the valve seat 23 is reduced, so that there is a problem that slow leakage is likely to occur from that portion. Also, when the outer circumferential seal diameter (Dp) of the valve shaft 21C is smaller than the seat diameter (Ds) of the valve seat 23, if there is slow leakage to the discharge pressure chamber 3C side via the pressure regulating valve 20C, the load acting in the valve opening direction increases, making it even more likely that fluid will leak. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 3594507 [Patent Document 2] JP 2011-256759 A [Patent Document 3] Japanese Utility Model Application Publication No. 59-160842 [Patent Document 4] Patent application 2022-088066 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention seeks to solve the above-mentioned problems, and has an objective of making it possible to prevent the occurrence of slow leak through a pressure regulating valve in an electronically controlled regulator even in a closed valve state where power supply to the electric motor is stopped. [Means for solving the problem]

[0013] Therefore, the present invention is an electronically controlled regulator comprising a pressure regulating valve comprising a valve stem coaxially provided with a valve disc inside a body forming an inlet and a discharge port and operable to reciprocate in an axial direction, a valve seat having a seat surface against which the valve disc can come into close contact on the side of a high-pressure fluid chamber connected to the inlet, and a discharge pressure regulating means for adjusting the pressure of the fluid by reciprocating the valve stem by driving an electronically controlled electric motor to change the distance between the valve disc and the valve seat, wherein the high-pressure fluid introduced into the high-pressure fluid chamber from the inlet is reduced in pressure and regulated by the pressure regulating valve and discharged from the discharge port as reduced-pressure fluid of a set pressure on the discharge pressure chamber side, a cylindrical space is formed on the discharge pressure chamber side, and a piston receiving fluid pressure from the discharge pressure chamber is fixed to the outer periphery of the valve stem and is disposed slidably within the space together with the valve stem, and when the electric motor is stopped to close the valve, the fluid pressure received by the piston is converted into a pressure load in a direction pressing the valve disc against the seat surface.

[0014] In this way, by providing a piston that receives the discharge pressure on the valve stem and converting the fluid pressure on the discharge pressure chamber side into a pressure load in the valve closing direction, even when the electric motor is stopped and the valve is closed, the pressure on the discharge pressure chamber side generates a load that operates the pressure regulating valve in the valve closing direction, thereby providing a self-sealing function and making it possible to prevent the occurrence of slow leaks through the pressure regulating valve.

[0015] Furthermore, in this electronically controlled regulator, if the outer peripheral seal diameter of the piston is larger than the seat diameter of the valve seat, and the pressure load obtained by subtracting the pressure receiving area of ​​the seat diameter from the pressure receiving area of ​​the outer peripheral seal diameter acts as a pressure load in a direction pressing the valve body against the seat surface, the pressure load operating the pressure regulating valve in the valve closing direction will be greater by the amount that the outer peripheral seal diameter of the piston is larger than the seat diameter of the valve seat, making it even easier to prevent the occurrence of slow leaks.

[0016] Furthermore, in the above-described electronically controlled regulator, when the piston is integrated with the valve stem on its inner periphery by bonding or welding, a seal member on the inner diameter side of the piston is not required, thereby reducing the number of parts of the product.

[0017] Alternatively, if the piston is provided separately from the valve stem, there is a high degree of freedom in the manufacturing process. Effect of the Invention

[0018] According to the present invention, a piston is provided on the valve stem to convert the fluid pressure on the discharge pressure chamber side into a pressure load in the valve closing direction, so that slow leakage through the pressure regulating valve can be prevented even when the power supply to the electric motor is stopped and the valve is closed. [Brief description of the drawings]

[0019] [Figure 1] 1 is a vertical cross-sectional view showing an electronically controlled regulator according to a first embodiment of the present invention in an open state; [Diagram 2] FIG. 2 is a vertical cross-sectional view showing the electronically controlled regulator of FIG. 1 in a valve-closed state. [Diagram 3] FIG. 5 is a vertical cross-sectional view showing an electronically controlled regulator according to a second embodiment of the present invention in an open state. [Figure 4] FIG. 4 is a vertical cross-sectional view showing the electronically controlled regulator of FIG. 3 in a valve-closed state. [Diagram 5]5 is an enlarged partial vertical cross-sectional view showing a different structure of a piston and a valve stem in the electronically controlled regulator of FIG. 4. [Figure 6] FIG. 1 is a vertical cross-sectional view showing an electronically controlled regulator previously applied for by the applicant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] Fig. 1 shows an electronically controlled regulator 1A according to a first embodiment of the present invention in an open state, and Fig. 2 shows it in a closed state. This electronically controlled regulator 1A is intended to be used as a pressure reducing means for reducing the pressure of gas fuel, which is a high-pressure fluid, to a predetermined pressure and delivering it in a supply system for gas fuel or the like.

[0022] Its configuration can be roughly divided into: inside a cylindrical metal body 10A, there is a high-pressure fluid chamber 2A which constitutes a high-pressure section from the inlet port of a fluid inlet passage 11, which introduces high-pressure fluid, to the valve portion of a pressure regulating valve 20A; a discharge pressure chamber 3A which constitutes a discharge pressure section from the valve portion of the pressure regulating valve 20A to the outlet port of a fluid delivery passage 12 which discharges reduced-pressure and regulated fluid; and a pressure control section 4A which is equipped with a discharge pressure adjustment means for adjusting and maintaining the pressure of the discharged fluid.

[0023] The pressure regulating valve 20A comprises a valve shaft 21A on which an umbrella-shaped valve element 22 is coaxially arranged and which can reciprocate in the axial direction, a donut-shaped valve seat 23 which has a seat surface 24 against which the valve element 22 can come into close contact and which has a valve hole formed in the center, and a discharge pressure regulating means which adjusts the discharge pressure by changing the distance between the valve element 22 and the valve seat 23 by reciprocating the valve shaft 21A.

[0024] The discharge pressure adjusting means includes a valve shaft moving structure, described later, which is actuated by the driving of the electric motor 30 to move the valve shaft 21 in the axial direction, and opens and closes the pressure regulating valve 20A so as to maintain the pressure of the discharged fluid at a set pressure while operating the valve shaft moving structure with the electric motor 30 based on the value of a pressure sensor (not shown) that is installed on the fluid delivery path 12 side and detects the pressure of the fluid after decompression. The pressure sensor may be installed in a pressure sensor installation section 14 connected in parallel to the fluid delivery path 12 by a communication hole 13, or may be installed at any position.

[0025] The electric motor 30 has a plurality of stators 31 supporting windings 32 wound therearound, and a substantially cylindrical rotor 33 having a plurality of magnets 34 arranged on the outer periphery so as to face each of the stators 31, and is arranged rotatably with its central axis coinciding with the valve shaft 21A.

[0026] In the electronically controlled regulator 1A, the valve shaft moving structure is a feed screw mechanism consisting of a combination of a trapezoidal male thread 51 formed on the outer peripheral surface of a cylindrical moving shaft 50A provided at the tip side of the valve shaft 21A and a trapezoidal female thread 35 formed on the inner peripheral surface of a rotor 33, which is a cylindrical member that constitutes part of the electric motor 30, and meshing with the trapezoidal male thread 51, and is configured so that when the electric motor 30 is driven, the trapezoidal female thread 35, which is integrated with the inner peripheral surface side of the rotor 33, rotates around the trapezoidal male thread 51.

[0027] The discharge pressure adjustment means is composed of the electric motor 30, a driver 40 which drives and controls the electric motor 30, and a moving shaft 50A which is coaxially connected to the valve shaft 21A by inserting the base end of the valve shaft 21A into a connecting hole 52 on the tip side, and the valve element 22 of the valve shaft 21A arranged below it is driven by the electronically controlled electric motor 30 to slide back and forth in the axial direction between a closed position (Figure 2) where the valve element 22 and the seat surface 24 are in close contact with each other and an open position (Figure 1) where they are separated, thereby changing the opening area and automatically adjusting the pressure of the reduced pressure fluid to be discharged so that it is equal to the set pressure.

[0028] The moving shaft 50A has an insertion hole 53 with a flat portion formed on its inner surface at the end opposite the connecting hole 52, and an anti-rotation shaft 60, whose base end 61 is fixed to the body 10A and whose tip 62 has a flat portion 63 formed on its outer surface, is inserted into the insertion hole 53 so as to be able to slide freely in the axial direction. The flat portions of the two shafts come into close contact with each other, thereby regulating the rotational movement of the moving shaft 50A and converting it into linear movement in the axial direction, thereby moving the valve shaft 21A connected by the connecting hole 52.

[0029] In this way, instead of adjusting the discharge pressure using only the spring 25, a method is adopted in which the electric motor 30 is driven and controlled based on discharge pressure data detected by a pressure sensor, while the opening / closing and valve open position of the valve element 22 provided on the valve shaft 21A are adjusted to adjust and maintain the set discharge pressure, making it possible to flexibly respond to fluctuations in the required flow rate and automatically maintain various set discharge pressures with one product without the need for replacing parts.

[0030] In this embodiment, a cylindrical space 36A is formed in a portion located on the tip side of the moving shaft 50A on the discharge pressure chamber 3A side, and a piston 37A having an outer diameter approximately equal to its inner diameter within the space 36A is arranged so as to be able to slide back and forth in the axial direction within the space 36A, with the piston 37A being coaxially fixed to the outer periphery of the valve shaft 21A and separating the space side accommodating the electric motor 30 and the moving shaft 50A from the discharge pressure chamber 3A side extending from the valve portion of the pressure regulating valve 20A to the discharge port of the fluid delivery path 12 by O-rings 70, 71 sealing the outer periphery and inner periphery sides thereof and dividing the space air-tight and liquid-tight.

[0031] In other words, the piston 37A is subjected to the reduced pressure fluid pressure in the discharge pressure chamber 3A and slides back and forth in the axial direction within the cylindrical space 36A, thereby causing the valve shaft 21A to reciprocate. In the closed valve state shown in FIG. 2 where the drive of the electric motor 30 is stopped, the fluid pressure in the discharge pressure chamber 3A received by the piston 37A is converted into a pressure load in a direction pressing the valve body 22 against the seat surface 24. This is the most distinctive feature of the present invention.

[0032] In this way, by providing the piston 37A, which receives the discharge pressure on the discharge pressure chamber 3A side, on the valve shaft 21A and adopting a configuration in which the reduced pressure fluid pressure is converted into a pressure load in the valve closing direction, a pressure load in the valve closing direction is added to the biasing force of the spring 25, making it possible to prevent the occurrence of slow leak via the pressure regulating valve 20A.

[0033] Even when the electric motor 30 is stopped from the open valve state shown in Figure 1, the fluid pressure in the discharge pressure chamber 3A causes the piston 37A to move upward as shown in the figure, pushing up the moving shaft 50A and generating a load that operates the valve shaft 21A in the valve closing direction, thereby providing a self-sealing function that increases the pressure pressing the valve body 22 against the seat surface 24.

[0034] 2, when the electric motor 30 is stopped and the valve is closed, the piston 37A has a central portion protruding from its base end in contact with the tip surface of the moving shaft 50A meshing with the inner diameter side of the rotor 33, and the base end side of the valve shaft 21A to which the piston 37A is fixed is fixed to the connecting hole 52 of the moving shaft 50A, so that it may seem difficult to move in the axial direction when the driving of the electric motor 30 is stopped. However, the resistance in the rotational direction of the rotor 33 is extremely small, and even when the driving of the electric motor 30 is stopped, the rotor 33 easily rotates with a slight axial biasing force on the moving shaft 50A while the moving shaft 50A moves in the axial direction, so there is no need to worry about impeding the movement of the piston 37A and the valve shaft 21A in the valve closing direction.

[0035] In addition, in this embodiment, the outer peripheral seal diameter (Dp) of the piston 37A is larger than the seat diameter (Ds) of the seat surface 24 at the valve seat 23, and the pressure load obtained by subtracting the pressure receiving area of ​​the seat diameter (Ds) from the pressure receiving area of ​​the outer peripheral seal diameter (Dp) acts as a pressure load in the direction of pressing the valve body 22 against the seat surface 24.

[0036] In other words, the pressure load that operates the pressure regulating valve 20A in the valve closing direction increases to the extent that the outer seal diameter (Dp) of the piston 37A is larger than the seat diameter (Ds) of the valve seat 22, and the pressure that presses the valve body 22 into contact with the seat surface 24 increases, making it even easier to prevent the occurrence of slow leaks.

[0037] In this embodiment, the inner periphery of the piston 37A is fixed via the O-ring 71 to a groove formed on the outer periphery of the valve shaft 21A, and the piston 37A and the valve shaft 21A are configured as separate bodies. However, they may be integrated by welding or bonding, in which case a sealing member such as the O-ring 71 is not required, which leads to a reduction in the number of parts.

[0038] Fig. 3 shows an electronically controlled regulator 1B according to a second embodiment of the present invention in an open state, and Fig. 4 shows the same in a closed state. Like the electronically controlled regulator 1A, this electronically controlled regulator 1B is intended to be used as a pressure reducing means for reducing the pressure of gas fuel, which is a high-pressure fluid, to a predetermined pressure and discharging it in a supply system for gas fuel or the like.

[0039] Broadly speaking, the configuration of this regulator is similar to that of the electronically controlled regulator 1A in that it is configured to include a high-pressure fluid chamber 2B which constitutes a high-pressure section from the inlet port of fluid inlet passage 11, which introduces high-pressure fluid, to the valve portion of pressure regulating valve 80 inside body 10B which is formed into a cylindrical shape from metal, a discharge pressure chamber 3B which constitutes a discharge pressure section from the valve portion of pressure regulating valve 80 to the discharge port of fluid delivery passage 12 which discharges reduced-pressure fluid, and a pressure control section 4B which reduces and adjusts the pressure of the reduced-pressure fluid discharged by operating pressure regulating valve 80 to a set pressure.

[0040] The pressure regulating valve 80 comprises a cylindrical valve shaft 81 on which a circular valve element 82 is coaxially arranged and which can reciprocate in the axial direction and has a passage 83 through which a fluid can pass, a circular valve seat 84 having a seat surface 85 with which the valve element 82 can come into close contact, and a discharge pressure regulating means for adjusting the discharge pressure of the fluid by reciprocating the valve shaft 81 to change the distance between the valve element 82 and the valve seat 84.

[0041] This discharge pressure adjusting means is composed of an electric motor 30, a driver 40 that controls the driving of the electric motor 30, and a moving shaft 50B that is formed integrally with the outer periphery of the valve shaft 81, and is similar to the electronically controlled regulator 1A in that the valve element 82 of the valve shaft 81, which is disposed penetrating this discharge pressure adjusting means, is reciprocated in the axial direction relative to the seat surface 85 of the valve seat 84 between a closed position (FIG. 4) where the valve element 82 and the seat surface 85 are in close contact with each other, and an open position (FIG. 3) where they are separated, thereby changing the opening area and adjusting the pressure of the discharged reduced pressure fluid to be equal to the set pressure.

[0042] In the electronically controlled regulator 1B of this embodiment as well, a cylindrical space 36B is formed in the discharge pressure chamber 3B on the base end side of the valve shaft 81 which is integral with the moving shaft 50B, at a position before the fluid delivery path 12, and a piston 37B having an outer diameter approximately the same as its inner diameter within the space 36B is coaxially fixed to the outer periphery side of the base end of the cylindrical valve shaft 81, and is arranged so as to be able to slide back and forth in the axial direction within the cylindrical space 33B, with the outer periphery and inner periphery sides being partitioned airtight and liquid-tight by the O-rings 70, 71 between the space side housing the electric motor 30 and the moving shaft 50B and the fluid delivery path 12 side of the discharge pressure chamber 3B.

[0043] That is, while receiving the reduced fluid pressure on the discharge pressure chamber 3B side, the piston 37B slides back and forth in the axial direction within the cylindrical space 36B, thereby reciprocating the valve shaft 81. When the driving of the electric motor 30 is stopped and the valve is closed as shown in FIG. 4, the fluid pressure within the discharge pressure chamber 3B received by the piston 37B is converted into a pressure load in a direction pressing the valve body 82 against the seat surface 85. This point is also common to the electronically controlled regulator 1A, and makes it possible to prevent slow leakage via the pressure regulating valve 80 even when the driving of the electric motor 30 is stopped and the valve is closed.

[0044] Also in this embodiment, as shown in FIG. 4, the outer peripheral seal diameter (Dp) of the piston 37B is larger than the seat diameter (Ds) of the seat surface 85 of the valve seat 84, and the pressure load obtained by subtracting the pressure receiving area of ​​the seat diameter (Ds) from the pressure receiving area of ​​the outer peripheral seal diameter (Dp) acts as a pressure load in the direction of pressing the valve body 82 against the seat surface 85.

[0045] Therefore, since the outer seal diameter (Dp) of the piston 37B is larger than the seat diameter (Ds) of the valve seat 82, the pressure load that operates the pressure regulating valve 80 in the valve closing direction becomes larger, making it even easier to prevent the occurrence of slow leak.

[0046] Incidentally, as shown in the enlarged longitudinal sectional partial view of FIG. 5, the base end side of the valve shaft 81 may be inserted into the through-hole of the piston 37C and fixed to the inner peripheral surface thereof by laser welding or the like, thereby making the valve shaft 81 and the piston 37C one piece. This makes it unnecessary to use a sealing member such as the O-ring 71 at the insertion portion of the valve shaft 81, thereby enabling the number of parts to be reduced.

[0047] As described above, the present invention provides an electronically controlled regulator that can prevent slow leakage through the pressure regulating valve even when the power supply to the electric motor is stopped and the valve is in a closed state. [Explanation of symbols]

[0048] 1A, 1B Electronically controlled regulator, 2A, 2B High pressure fluid chamber, 3A, 3B Discharge pressure chamber, 4A, 4B Pressure control section, 10A, 10B Body, 11 Fluid inlet passage, 12 Fluid outlet passage, 13 Communication hole, 14 Pressure sensor installation section, 20A Pressure regulating valve, 21A Valve shaft, 22 Valve body, 23 Valve seat, 24 Seat surface, 25 Spring, 30 Electric motor, 31 Stator, 32 Winding, 33 Rotor, 34 Magnet, 35 Trapezoidal female thread, 36A, 36B Space, 37A, 37B, 37C Piston, 40 Driver, 50A, 50B Motion shaft, 51 Trapezoidal male thread, 52 Connection hole, 53 Insertion hole, 60 Anti-rotation shaft, 61 Base end, 62 Tip, 63 Flat portion, 70 O-ring, 71 O-ring, 80 pressure adjusting valve, 81 valve stem, 82 valve body, 83 passage, 84 valve seat, 85 seat surface

Claims

1. an electronically controlled regulator comprising: a valve stem having a valve body coaxially disposed within a body forming an inlet and a discharge port, the valve stem being capable of reciprocating in an axial direction; a valve seat having a seat surface with which the valve body can come into close contact on the side of a high-pressure fluid chamber adjacent to the inlet; and a discharge pressure regulating means for adjusting the pressure of the fluid by driving an electronically controlled electric motor to reciprocate the valve stem and change the distance between the valve body and the valve seat, wherein the high-pressure fluid introduced into the high-pressure fluid chamber from the inlet is reduced in pressure and regulated by the pressure regulating valve and discharged from the discharge port as reduced-pressure fluid of a set pressure on the discharge pressure chamber side, an electronically controlled regulator characterized in that a cylindrical space is formed on the discharge pressure chamber side, a piston that receives fluid pressure in the discharge pressure chamber is fixed to an outer periphery of the valve stem and is arranged to be able to slide within the space together with the valve stem, and when driving of the electric motor is stopped and the valve is closed, the fluid pressure received by the piston is converted into a pressure load in a direction pressing the valve body against the seat surface.

2. 2. The electronically controlled regulator according to claim 1, wherein an outer peripheral seal diameter of the piston is larger than a seat diameter of the valve seat, and a pressure load obtained by subtracting a pressure receiving area of ​​the seat diameter from a pressure receiving area of ​​the outer peripheral seal diameter acts as a pressure load in a direction pressing the valve body against the seat surface.

3. 3. The electronically controlled regulator according to claim 1, wherein the piston is integrated with the valve stem at its inner periphery by adhesion or welding.

4. 3. The electronically controlled regulator according to claim 1, wherein the piston is provided separately from the valve stem.

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