Electronically controlled regulator

Abstract

The technical problem of the present invention is to prevent the occurrence of slow leakage through a pressure regulating valve when the valve is closed, and to prevent the variation of discharge pressure caused by a backlash provided in a valve shaft movement structure for an electronically controlled regulator. The technical means of the present invention is that an electronically controlled regulator (1A) includes a pressure regulating valve including a discharge pressure regulating unit that reciprocates a valve shaft (21A) by a valve shaft movement structure by a feed screw (60) while changing the distance between a valve body (22A) and a valve seat (23A) to regulate the pressure of a fluid, in the electronically controlled regulator (1A), a piston (37A) for receiving the fluid pressure of a discharge pressure chamber (3A) is slidably disposed, a spring (70) for constantly urging the valve shaft (21A) in the valve closing direction is disposed, when the valve is closed, the fluid pressure received by the piston (37A) is converted into a pressure load in the direction in which the valve body (22A) is pressed, and when the pressure is adjusted, the pressure load is adjusted to the pressure load in the direction in which the valve body (22A) is pressed. Position displacement of the valve shaft (21A) due to backlash provided in a meshing portion of the feed screw (60) is avoided by applying force of the spring (70).

Description

Technical Field

[0001] The present invention relates to a regulator that decompresses and regulates a high-pressure fluid such as gaseous fuel to a specified pressure and discharges it, and more particularly to an electronically controlled regulator that regulates the pressure of the fluid to be discharged by electronic control. Background Art

[0002] As a regulator that decompresses a high-pressure fluid to a specified pressure and sends it out, for example, a regulator for gaseous fuel described in Japanese Patent No. 3594507 (Patent Document 1) is well known. This regulator is configured to include: a valve shaft provided coaxially with a valve element; and a doughnut-shaped seat portion having a valve hole penetrating through the center thereof and having a valve seat surface against which the valve element abuts. High-pressure fluid such as CNG flowing in from the inlet of the main body applies a force to the valve shaft that is configured to be able to reciprocate in the axial direction with the valve element in an open state of the valve element by a pressure regulating spring, so that the valve element abuts and presses against the valve seat surface at a specified pressure, and while decompressing and regulating the high-pressure gaseous fuel to a specified pressure, discharges it.

[0003] However, in the decompression structure of the conventional regulator as described above, the discharge pressure of the fluid regulated by the regulator mechanically depends on the load of the pressure regulating spring. Therefore, it is necessary to prepare a pressure regulating spring in advance for each specified discharge pressure. In addition, in a regulator used in a fuel supply system of a vehicle, the pressure regulating spring is fixed in advance at a specified installation height. Therefore, when the engine requires a large flow rate, the pressure drop becomes large, and when the engine requires a small flow rate, the pressure drop becomes small. Therefore, there is a problem that the discharge pressure range and the flow rate range are mechanically limited.

[0004] On the other hand, Japanese Utility Model Laid-Open No. 59-160842 (Patent Document 2) proposes a pressure regulating mechanism. In an LPG regulator including a primary side diaphragm chamber and a secondary side diaphragm chamber, an applied force adjusting unit that adjusts the applied force of a pressure regulating spring in the primary side diaphragm chamber includes a stepping motor that is pulse-controlled while corresponding to an output signal from a pressure sensor provided in the primary side diaphragm chamber.

[0005] In this way, by a pressure regulating mechanism including an electronically controlled stepping motor, when the pressure in the primary side diaphragm chamber is higher than a preset pressure, the applied force of the pressure regulating spring is weakened, and when the pressure in the primary side diaphragm chamber is lower than the preset pressure, the applied force of the pressure regulating spring is strengthened, so that the pressure in the primary side diaphragm chamber can be maintained at a desired pressure.

[0006] However, in this electronically controlled regulator, only the pressure in the primary side diaphragm chamber can be adjusted to the desired pressure and maintained. The pressure of the fuel discharged from the secondary side diaphragm chamber depends on the pressure regulating spring disposed in its chamber. Therefore, it is still difficult to set various discharge pressures with a single regulator, and the problems of mechanically limited discharge pressure range and flow rate range cannot be solved yet.

[0007] Therefore, the inventors and applicants of the present application previously proposed in Japanese Patent Application No. 2022-088066 (Patent Document 3) a regulator implemented by electronic control of an electric motor as shown in Figure 5 The electronically controlled regulator 1C includes inside a cylindrical main body 10C: a high-pressure fluid chamber 2C that forms a path from the inlet of the fluid introduction path 11 for introducing high-pressure fluid to the valve portion of the pressure regulating valve 20C; a discharge pressure chamber 3C that forms a path from this valve portion to the discharge port of the fluid delivery portion 12 for discharging the decompressed fluid; and a pressure regulating portion 4C that serves as a discharge pressure regulating unit that decompresses and regulates the pressure of the fluid to be discharged to a specified pressure while operating the pressure regulating valve 20C.

[0008] In addition, this discharge pressure regulating unit constitutes a valve shaft movement structure that, while operating by driving an electric motor 30C, moves a cylindrical valve shaft 21C in the axial direction to change the distance between a valve element 22C and a valve seat 23C. The discharge pressure regulating unit operates its valve shaft movement structure by the electric motor 30C based on the value of a pressure sensor that detects the pressure of the decompressed fluid, and opens and closes the pressure regulating valve 20C in such a way as to maintain the pressure of the decompressed fluid at the set pressure.

[0009] In this way, not only the discharge pressure is adjusted by a spring 25 disposed on the front end side of the valve shaft 21C, but also the opening and closing action of the valve element 22C provided on the valve shaft 21C is performed while driving and controlling the electric motor 30C based on the discharge pressure detected by the sensor to maintain the set discharge pressure. Thus, while being able to flexibly respond to changes in the required flow rate, it exhibits the function of automatically maintaining various set discharge pressures.

[0010] However, in such an electronically controlled regulator 1C, when the power supply to the electric motor 30C is stopped during engine stoppage or the like and the valve is closed, the load that causes the valve element 22C to move in the closing direction is only the applied force of the spring 25 provided on the valve shaft 21C, and the pressing force against the valve seat surface 24 of the valve seat 23C becomes small. Therefore, there is a problem that slow leakage is likely to occur from this part. In addition, in the case where the diameter (Dp) of the outer peripheral seal of the valve shaft 21C < the diameter (Ds) of the seat portion of the valve seat 23C, if there is slow leakage on the discharge pressure chamber 30C side via the pressure regulating valve 20C, the load acting in the valve opening direction increases and the fluid is more likely to leak.

[0011] Therefore, the inventors and applicants of the present application proposed an electronically controlled regulator 1B in Japanese Patent Application No. 2023-087018 (Patent Document 4) in addition to the structure of the above-mentioned electronically controlled regulator 1C. As Figure 4 shown, a cylindrical space is formed on the discharge pressure chamber 3B side thereof. The piston 37B that bears the fluid pressure in the discharge pressure chamber 3B is arranged to be slidable in the space together with the valve shaft 21B while being fixed to the outer peripheral side of the valve shaft 21B. When the valve is closed by stopping the drive of the electric motor 30B, the fluid pressure borne by the piston 37B is converted into a pressure load in the direction of pressing the valve element 22B against the valve seat surface 24B of the valve seat 23B, and this electronically controlled regulator 1B can reduce the aforementioned slow leakage.

[0012] However, in this electronically controlled regulator 1B, when the trapezoidal external thread 61 provided on the outer peripheral surface of the valve shaft 21B of the feed screw 60 that constitutes its valve shaft movement structure meshes with the trapezoidal internal thread 62 provided on the inner peripheral surface of the rotor 31B, in order to prevent edge biting, as shown in the enlarged view of the feed screw 60 part Figure 2 shown, a backlash X (play) is provided between the thread teeth. During pressure regulation, corresponding to the pressure balance between the high-pressure fuel chamber 2B at the fuel inlet and the low-pressure fuel chamber 3B on the discharge side, as Figure 3 shown, the valve shaft 21B and the valve element 22B are offset by an amount corresponding to the backlash X. As a result of such a change in the opening area, there is a problem of a sharp change in the discharge pressure. Prior Art Documents Patent Documents

[0013] Patent Document 1: Japanese Patent No. 3594507 Gazette; Patent Document 2: Japanese Utility Model Publication No. 59-160842; Patent Document 3: Japanese Patent Application No. 2022-088066; Patent Document 4: Japanese Patent Application No. 2023-087018. Summary of the Invention Technical problem to be solved by the invention

[0014] The present invention is to solve the above problems. The technical problem is that for an electronically controlled regulator, in addition to preventing slow leakage via a pressure regulating valve when the valve is closed, it can also avoid fluctuations in the discharge pressure caused by backlash in the valve shaft movement structure. Means for solving the technical problem

[0015] Therefore, the present invention is characterized in that an electronically controlled regulator includes a pressure regulating valve inside a main body formed with an inlet and an outlet. The pressure regulating valve is composed of a valve shaft, a valve seat, and a discharge pressure regulating unit. The valve shaft is coaxially provided with a valve core and can reciprocate in the axial direction. The valve seat has a valve seat surface on the side of the high-pressure fluid chamber continuous with the inlet and can be in close contact with the valve core. The discharge pressure regulating unit is driven by an electronically controlled electric motor, and the valve shaft reciprocates through a valve shaft movement structure composed of a feed screw provided between the outer peripheral surface of the valve shaft and the inner peripheral surface of the rotor, and at the same time, the distance between the valve core and the valve seat changes, thereby regulating the pressure of the fluid. The electronically controlled regulator reduces and regulates the high-pressure fluid introduced from the inlet into the high-pressure fluid chamber through the pressure regulating valve, and at the same time, the reduced-pressure fluid as the set pressure is discharged from the outlet on the discharge pressure chamber side. Among them, in the electronically controlled regulator, a cylindrical space is formed in the discharge pressure chamber. A piston that bears the fluid pressure in the discharge pressure chamber is arranged to be able to slide in the space together with the valve shaft in a state fixed to the outer peripheral side of the valve shaft. And a spring is arranged in the space. The front end side of the spring abuts against the piston and always applies a force to the valve shaft in the valve closing direction. When the electric motor stops and the valve is closed, in addition to the fluid pressure borne by the piston being converted into a pressure load in the direction of pressing the valve core against the valve seat surface, during pressure regulation, the position deviation of the valve shaft caused by the backlash of the meshing part of the feed screw is avoided by the applied force of the spring.

[0016] In this way, a piston is provided. When the electric motor stops, the piston bears the fluid pressure in the discharge pressure chamber and presses the valve core against the valve seat surface, while preventing slow leakage. And a spring is provided on the discharge pressure chamber side, and the spring always applies a force to the piston and the valve shaft in the valve closing direction. Therefore, a position deviation corresponding to the backlash provided in the valve shaft movement structure between the electric motor and the valve shaft will not occur on the valve shaft, and thus, it is possible to effectively avoid a sudden change in the discharge pressure caused by a change in the valve opening area due to the position deviation of the valve shaft corresponding to the pressure balance between the high-pressure fuel chamber and the low-pressure fuel chamber.

[0017] In addition, in this electronic regulator, the electric motor is an AC servo motor or a DC brushless motor, the valve shaft movement structure is a feed screw composed of a trapezoidal external thread and a trapezoidal internal thread, the trapezoidal external thread is formed on the outer peripheral surface of a cylindrical moving shaft attached coaxially with the valve shaft, the trapezoidal internal thread is formed on the inner peripheral surface of the rotor and meshes with the trapezoidal external thread, and by driving the electric motor, the trapezoidal internal thread rotates around the trapezoidal external thread. Thus, it moves in the axial direction without rotating the trapezoidal external thread, and at the same time moves the valve shaft. If the above is the feature, it is possible to move the valve shaft to the open valve position or the closed valve position and accurately stop it in a short time without making the main body overly large.

[0018] Furthermore, in the above electronic control regulator, the valve shaft is composed of a cylindrical member, the cylindrical member is coaxially provided with an annular valve core and has a passage through which fluid can pass, and the front-end side valve core is actuated by the discharge pressure regulating unit to change the distance between the valve core and the valve seat surface of the valve seat, thereby regulating the discharge pressure of the fluid. If the above is the feature, the above function can be reliably exerted with a relatively simple structure. Advantages of the Invention

[0019] According to the present invention in which a spring always applies a force to a piston pressing the valve core against the valve seat surface in the valve closing direction when the electric motor stops, in addition to preventing slow leakage occurring via the pressure regulating valve when the motor stops, it is also possible to avoid fluctuations in the discharge pressure caused by backlash provided in the valve shaft movement structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a longitudinal sectional view of an electronic control regulator showing an embodiment of the present invention. Figure 2 is shown in Figure 1 , Figure 4 a partial enlarged view of the backlash provided on the feed screw of the electronic control regulator. Figure 3 is shown when the valve shaft moves in the Figure 2 valve opening direction (black arrow direction) by an amount equivalent to the backlash. Figure 4 is a longitudinal sectional view of an electronic control regulator of an existing example. Figure 5 is a longitudinal sectional view of an electronic control regulator of a different existing example. REFERENCE SIGNS 1A Electronic control type regulator; 2A High-pressure fluid chamber; 3A Discharge pressure chamber; 4A Pressure control section; 10A Main body; 11 Fluid introduction path; 12 Fluid delivery path; 20A Pressure regulating valve; 21A Valve shaft; 22A Valve element; 23A Valve seat; 24A Valve seat surface; 27 Passage; 30A Electric motor; 31A Rotor; 37A Piston; 40A Driver; 50A Drive shaft; 60 Feed screw; 61 Trapezoidal external thread; 62 Trapezoidal internal thread; 70 Spring. Detailed implementation mode

[0021] Hereinafter, with reference to the drawings, the mode for implementing the present invention will be described.

[0022] Figure 1 It shows the state when the electronic control type regulator 1A of an embodiment of the present invention is in the closed valve state. It is assumed that this electronic control type regulator 1A is mainly used as a pressure reducing unit that reduces a high-pressure fluid such as gaseous fuel to a specified pressure and then delivers it in a supply system such as gaseous fuel.

[0023] If its structure is generally divided for description, inside the main body 10A made of metal and formed in a cylindrical shape, it is composed of a high-pressure fluid chamber 2A, a discharge pressure chamber 3A, and a pressure control section 4A. Among them, the high-pressure fluid chamber 2A constitutes the high-pressure part from the inlet of the fluid introduction path 11 for introducing high-pressure fluid to the valve part of the pressure regulating valve 20A, the discharge pressure chamber 3A constitutes the discharge pressure part from the valve part of the pressure regulating valve 20A to the discharge port of the fluid delivery path 12 for discharging the reduced and regulated fluid, and the pressure control section 4A includes a discharge pressure regulating unit for regulating and maintaining the pressure of the discharged fluid.

[0024] The pressure regulating valve 20A is composed of a valve shaft 21A, a doughnut-shaped valve seat 23A, and a discharge pressure regulating unit. Among them, the valve shaft 21A is composed of a cylindrical member and is arranged to be able to reciprocate in the axial direction. The cylindrical member is coaxially provided with an annular valve body 22A and has a passage 27 through which fluid can pass. The valve seat 23A has a valve seat surface 24A that can be in close contact with the valve element 22A and has a valve hole formed in the center. The discharge pressure regulating unit changes the distance between the valve element 22A and the valve seat 23A by reciprocating the valve shaft 21A, thereby regulating the discharge pressure.

[0025] The discharge pressure regulating unit is composed of an electric motor 30A including a rotor 31A, a driver 40A for driving and controlling the same, and a drive shaft 50A coaxially connected to the valve shaft 21A, and is configured as follows: By driving the electronically controlled electric motor 30A, by means of a valve shaft movement structure constituted by a feed screw 60 provided between the outer peripheral surface of the valve shaft 21A and the inner peripheral surface of the rotor 31A, the valve element 22A on the front end side of the valve shaft 21A is made to reciprocate in the axial direction between a closed valve position where the valve element 22A is in close contact with the valve seat surface 24A of the valve seat 23A and an open valve position where they are separated, so as to change the opening area, and at the same time, it is automatically adjusted so that the pressure of the discharged decompressed fluid is equal to the set pressure.

[0026] That is, it is configured as follows: The electric motor 30A is driven and controlled based on the data of the discharge pressure detected by a pressure sensor (not shown), and at the same time, the opening and closing or the adjustment of the open valve position of the valve element 22A provided on the valve shaft 21A is performed, so as to adjust and maintain the set discharge pressure, and it can flexibly respond to changes in the required flow rate, and at the same time, it can automatically maintain various set discharge pressures. In addition, as the electric motor 30A, from the viewpoint of adjustability, an AC servo motor or a DC brushless motor is preferably used.

[0027] Moreover, in the electronically controlled regulator 1A of the present embodiment, a cylindrical space is formed in the discharge pressure chamber 3A on the base end side of the valve shaft 21A in the main body 10A, and a piston 37A that bears the fluid pressure in the discharge pressure chamber 3A is disposed together with the valve shaft 21A in a state of being fixed to the outer peripheral side of the valve shaft 21A so as to be slidable in this space.

[0028] Thus, when the valve is closed with the electric motor 30A stopped, the fluid pressure on the discharge pressure chamber 3A side borne by the piston 37A is converted into a pressure load in the direction of pressing the valve element 22A against the valve seat surface 24A, so that slow leakage through the pressure regulating valve 20A due to a decrease in the pressing force of the valve seat 23A against the valve seat surface 24A can be prevented.

[0029] On the other hand, in the above-mentioned existing electronically controlled regulator 1B, as Figure 2As shown, on the feed screw 60 that constitutes its valve shaft movement structure, a backlash (play) X is provided between the thread flanks to prevent seizing between the trapezoidal internal thread 62 and the trapezoidal external thread 61 during meshing. Therefore, there is the following problem: When adjusting the pressure, the pressure balance between the pressure regulating valve 20B, the high-pressure fluid chamber 2B, and the discharge pressure chamber 3B correspondingly shifts by an amount equivalent to the backlash X, causing the valve opening area to change and the discharge pressure to fluctuate sharply. However, in the electronically controlled regulator 1A of the present embodiment, since a backlash is also provided on the feed screw 60, the same problem is also conceivable.

[0030] Therefore, in the present embodiment, in the space on the discharge pressure chamber 3A side where the piston 37A is disposed, the spring 70 is disposed in a compressed state such that the front end side abuts against the pressure receiving surface side of the piston 37A and always applies a force to the valve shaft 21A in the valve closing direction, which is a feature of the present invention.

[0031] Thereby, the applied force of the spring 70 is applied to the piston 37A, so that the trapezoidal internal thread 62 and the trapezoidal external thread 61 that constitute the feed screw 60 do not shift in the axial direction from the state of always being in close contact, and it is possible to prevent the valve shaft 21A from shifting in position by an amount equivalent to the backlash X preset on the feed screw 60. Therefore, it is possible to avoid a sharp change in the discharge pressure corresponding to the pressure balance between the high-pressure fluid chamber 2A and the discharge pressure chamber 3A.

[0032] As described above, for the electronically controlled regulator, by the present invention, in addition to being able to prevent slow leakage via the pressure regulating valve during valve closing, it is also possible to avoid fluctuations in the discharge pressure caused by the backlash provided in the valve shaft movement structure.

Claims

1. An electronically controlled regulator, comprising a pressure regulating valve in a main body having an inlet and a discharge port, wherein the pressure regulating valve is composed of a valve shaft, a valve seat and a discharge pressure regulating unit, wherein the valve shaft is coaxially provided with a valve core and can reciprocate along an axial direction, the valve seat having a valve seat surface capable of tightly contacting the valve core on a high-pressure fluid chamber side continuous with the inlet, the discharge pressure regulating unit drives an electronically controlled electric motor, and reciprocates the valve shaft through a valve shaft moving structure composed of a feed screw disposed between an outer peripheral surface of the valve shaft and an inner peripheral surface of a rotor, and changes a distance between the valve core and the valve seat, thereby regulating the pressure of the fluid, the electronically controlled regulator reduces and regulates the high-pressure fluid introduced from the inlet into the high-pressure fluid chamber through the pressure regulating valve, and discharges the reduced-pressure fluid as a set pressure on the discharge pressure chamber side from the discharge port, It is characterized in that A cylinder-shaped space is formed in the discharge pressure chamber, and a piston that receives the fluid pressure of the discharge pressure chamber is arranged to be able to slide in the space together with the valve shaft while being fixed to the outer peripheral side of the valve shaft, and a spring is arranged in the space, the front end side of the spring abuts against the piston and always applies force to the valve shaft in the valve closing direction. When the electric motor stops and the valve is closed, in addition to the fluid pressure received by the piston being converted into a pressure load in the direction of pressing the valve core against the valve seat surface, the position deviation of the valve shaft caused by the tooth clearance of the meshing part of the feed screw is avoided by the application force of the spring during pressure adjustment.

2. The electronically controlled regulator according to claim 1, characterized in that: The electric motor is an AC servo motor or a DC brushless motor, and the valve shaft moving structure is a feed screw composed of a trapezoidal external thread and a trapezoidal internal thread. The trapezoidal external thread is formed on the outer peripheral surface of a cylindrical moving shaft coaxially attached to the valve shaft, and the trapezoidal internal thread is formed on the inner peripheral surface of the rotor and meshes with the trapezoidal external thread. The trapezoidal internal thread is driven by the electric motor to rotate around the trapezoidal external thread, thereby moving along the axial direction without rotating the trapezoidal external thread and moving the valve shaft at the same time.

3. The electronically controlled regulator according to claim 1 or 2, characterized in that: The valve shaft is composed of a cylindrical component, which is coaxially provided with an annular valve core and has a passage for fluid to pass through. The valve core on the front end side is actuated by the discharge pressure regulating unit to change the distance between the valve seat surface and the discharge pressure of the fluid.

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