Electronic control type regulator

Abstract

To prevent occurrence of slow leakage via a pressure regulating valve during valve closing and avoid fluctuation of discharge pressure derived from a backlash provided in a valve stem movement structure in an electronic control type regulator.SOLUTION: An electronic control type regulator 1A has a pressure regulating valve including discharge pressure regulating means for regulating pressure of fluid by changing a distance between a valve element 22A and a valve seat 23A while reciprocating a valve stem 21A by using a valve stem movement mechanism using a feed screw 60. A piston 37A that receives fluid pressure of a discharge pressure chamber 3A is slidably disposed and a spring 70 for normally energizing the valve stem 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 a direction of pressing the valve element 22A, and when the pressure is regulated, positional deviation of the valve stem 21A caused by a backlash provided in an engagement portion of the feed screw 60 is avoided by using energizing force of the spring 70.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a regulator that discharges a high-pressure fluid such as gaseous fuel while reducing the pressure and adjusting it to a predetermined pressure, and more particularly to an electronically controlled regulator that adjusts the pressure of the discharged fluid by electronic control.

Background Art

[0002] As a regulator that reduces the pressure of a high-pressure fluid and delivers it at a predetermined pressure, for example, a regulator for gaseous fuel described in Japanese Patent No. 3594507 (Patent Document 1) is well known. This regulator includes a valve shaft provided coaxially with a valve body and a donut-shaped seat portion having a seat surface through which a valve hole penetrates in the center and with which the valve body is in close contact. High-pressure fluid such as CNG flowing in from the inlet of the body is reciprocally slidable in the axial direction with respect to the valve body in the open state of the valve body, and the valve body is urged by a pressure regulating spring so as to be pressed against the seat surface at a predetermined pressure. It has a structure that discharges high-pressure gaseous fuel while reducing the pressure and adjusting it to a predetermined pressure.

[0003] However, in the pressure reducing structure of such a conventional regulator, since the discharge pressure of the fluid by the regulator mechanically depends on the load of the pressure regulating spring, it is necessary to prepare a pressure regulating spring in advance for each specified discharge pressure. In addition, in a regulator used in a vehicle fuel supply system, since the pressure regulating spring is fixed in advance to a specified set height, when the engine required flow rate is large, the pressure drop becomes large, and when the required flow rate is small, the pressure drop becomes small. Therefore, there has been 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 provided with a stepping motor that is pulse-controlled while corresponding to an output signal from a pressure sensor provided in a primary diaphragm chamber as an urging force adjusting means for adjusting the urging force of a pressure regulating spring in a primary diaphragm chamber in an LPG regulator having a primary diaphragm chamber and a secondary diaphragm chamber.

[0005] In this way, by means of a pressure regulating mechanism equipped with an electronically controlled stepping motor, when the pressure in the primary diaphragm chamber becomes higher than a preset pressure, the biasing force of the pressure regulating spring is weakened, and when the pressure in the primary diaphragm chamber becomes lower than the preset pressure, the biasing force of the pressure regulating spring is strengthened, enabling the pressure in the primary diaphragm chamber to be maintained at a desired pressure.

[0006] However, in this electronically controlled regulator, only the pressure in the primary diaphragm chamber can be adjusted and maintained at a desired pressure. Since the pressure of the fuel discharged from the secondary diaphragm chamber depends on the pressure regulating spring disposed therein, it is still difficult to set various discharge pressures with a single type of regulator. Also, the problems of mechanically limited discharge pressure ranges and flow rate ranges have not been solved.

[0007] In contrast, the inventors and applicants of the present application previously proposed a regulator by electronic control of an electric motor as shown in FIG. 5 in Japanese Patent Application No. 2022-088066 (Patent Document 3). This electronically controlled regulator 1C includes, inside a cylindrical body 10C, a high-pressure fluid chamber 2C that constitutes the path from the inlet of a fluid introduction path 11 for introducing high-pressure fluid to the valve portion of a pressure regulating valve 20C, a discharge pressure chamber 3C that constitutes the path from the valve portion to the outlet of a fluid discharge path 12 for discharging decompressed fluid, and a pressure adjustment portion 4C as discharge pressure adjustment means for decompressing and adjusting the pressure of the fluid discharged while operating the pressure regulating valve 20C to a predetermined pressure.

[0008] And the discharge pressure adjustment means constitutes a valve shaft movement structure that moves a cylindrical valve shaft 21C in the axial direction while operating by driving an electric motor 30C to change the distance between a valve body 22C and a valve seat 23C, and based on the value of a pressure sensor that detects the pressure of the decompressed fluid, the opening and closing of the pressure regulating valve 20C is performed while operating the valve shaft movement structure with the electric motor 30C so that the pressure of the decompressed fluid maintains the set pressure.

[0009] Thus, instead of adjusting the discharge pressure only with the spring 25 disposed on the tip side of the valve shaft 21C, the opening and closing operation of the valve body 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, and by adopting a method of maintaining the set discharge pressure, it is possible to flexibly respond to fluctuations in the required flow rate and to exhibit the function of automatically maintaining various set discharge pressures.

[0010] However, in such an electronically controlled regulator 1C, when the valve is closed with the power supply to the electric motor 30C stopped, such as when the engine stops, the load for operating the valve body 22C in the closing direction becomes only the biasing force of the spring 25 provided on the valve shaft 21C, and the pressing force on the seat surface 24 of the valve seat 23C becomes small. Therefore, there is a problem that a slow leak is likely to occur from that portion. Also, when the relationship of the outer peripheral seal diameter (Dp) of the valve shaft 21C < the seat diameter (Ds) of the valve seat 23C, if there is a slow leak on the discharge pressure chamber 3C side via the pressure regulating valve 20C, the load acting in the valve opening direction increases and the fluid becomes more likely to leak.

[0011] Therefore, the inventors / applicants of the present application, in Japanese Patent Application No. 2023-087018 (Patent Document 4), in addition to the configuration of the above-described electronically controlled regulator 1C, as shown in FIG. 4, a cylindrical space is formed on the discharge pressure chamber 3B side, and a piston 37B that receives the fluid pressure in the discharge pressure chamber 3B is fixed to the outer peripheral side of the valve shaft 21B and is arranged slidably in the space together with the valve shaft 21B. When the valve is closed with the driving of the electric motor 30B stopped, the fluid pressure received by the piston 37B is converted into a pressure load in the direction of pressing the valve body 22B against the seat surface 24B of the valve seat 23B, and an electronically controlled regulator 1B of this type has been proposed, which can reduce the above-described slow leak.

[0012] However, also in this electronic control type regulator 1B, when the trapezoidal male thread 61 provided on the outer peripheral surface of the valve shaft 21B constituting the feed screw 60 of the valve shaft movement structure meshes with the trapezoidal female thread 62 provided on the inner peripheral surface of the rotor 31B, in order to prevent the occurrence of galling, as shown in FIG. 2 where the feed screw 60 portion is enlarged, backlash X (play) is provided between the threads. During pressure regulation, according 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 shown in FIG. 3, the valve shaft 21B and the valve body 22B shift by the amount of backlash X, and as a result of this changing the opening area, there is a problem that the discharge pressure fluctuates suddenly.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0014] The present invention aims to solve the above problems, and for an electronic control type regulator, in addition to preventing the occurrence of slow leakage through a pressure regulating valve when the valve is closed, it is an object to be able to avoid fluctuations in the discharge pressure resulting from backlash provided in the valve shaft movement structure.

Means for Solving the Problems

[0015] Therefore, the present invention provides a pressure regulating valve comprising: a valve shaft coaxially provided inside a body having an inlet and an outlet and capable of reciprocating in the axial direction; a valve seat having a seat surface on the high-pressure fluid chamber side following the inlet, against which the valve body can be brought into close contact; and a discharge pressure adjusting means for adjusting the fluid pressure by changing the distance between the valve body and the valve seat while reciprocating the valve shaft by a feed screw provided between the outer peripheral surface of the valve shaft and the inner peripheral surface of a rotor driven by an electronically controlled electric motor. In an electronically controlled regulator that discharges the high-pressure fluid introduced into the high-pressure fluid chamber from the inlet as a decompressed fluid at a set pressure on the discharge pressure chamber side while decompressing and adjusting it with the pressure regulating valve, a cylindrical space is formed in the discharge pressure chamber, and a piston that receives the fluid pressure in the discharge chamber pressure chamber is slidably disposed in the space together with the valve shaft while being fixed to the outer peripheral side of the valve shaft. A spring that always biases the valve shaft in the valve closing direction while abutting the tip side against the piston is disposed in the space. When the valve is closed with the electric motor stopped, in addition to the fluid pressure received by the piston being converted into a pressure load in the direction of pressing the valve body against the seat surface, during pressure regulation, the biasing force of the spring avoids the occurrence of a positional deviation of the valve shaft due to the backlash provided at the meshing portion of the feed screw.

[0016] Thus, by providing a piston that receives the fluid pressure in the discharge pressure chamber when the electric motor stops and prevents slow leakage while pressing the valve body against the seat surface, and by providing a spring that always biases the piston and the valve shaft in the valve closing direction on the discharge pressure chamber side, no positional deviation due to the backlash provided in the valve shaft movement structure between the electric motor and the valve shaft occurs in the valve shaft. Therefore, it is possible to effectively avoid sudden fluctuations in the discharge pressure caused by changing the valve opening area due to the positional deviation of the valve shaft according to the pressure balance between the high-pressure fuel chamber and the low-pressure fuel chamber.

[0017] Also, in this electronic regulator, the electric motor is an AC servo motor or a DC brushless motor, and the valve shaft movement structure is a feed screw formed by a combination of a trapezoidal male screw formed on the outer peripheral surface of a columnar movement shaft coaxially attached to the valve shaft and a trapezoidal female screw formed on the inner peripheral surface of the rotor and meshing with the trapezoidal male screw. When the trapezoidal female screw rotates around the trapezoidal male screw by driving the electric motor, the valve shaft is moved in the axial direction without rotating the trapezoidal male screw. If it is characterized in this way, the valve shaft can be moved to the valve opening position or the valve closing position in a short time and accurately stopped without excessively enlarging the body.

[0018] Furthermore, in the above-described electronically controlled regulator, the valve shaft is composed of a cylindrical member having an annular valve body coaxially provided and having a passage through which fluid can pass. By operating the discharge pressure adjusting means so as to change the distance between the valve body on the tip side and the seat surface of the valve seat, if it is characterized in that the discharge pressure of the fluid is adjusted, the above-described functions can be surely exhibited with a relatively simple configuration.

Advantages of the Invention

[0019] According to the present invention, in which a piston that presses the valve body against the seat surface when the electric motor stops is always biased in the valve closing direction by a spring, in addition to preventing the occurrence of slow leakage through the pressure regulating valve when the motor stops, it becomes possible to avoid fluctuations in the discharge pressure resulting from backlash provided in the valve shaft movement structure.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0022] FIG. 1 shows a state when the electronic control regulator 1A, which is an embodiment of the present invention, is in a closed valve state. This electronic control regulator 1A is mainly assumed to be used as a pressure reducing means for delivering a high-pressure fluid such as gas fuel while reducing its pressure to a predetermined pressure in a supply system such as a gas fuel supply system.

[0023] Explaining its configuration in a large classification, inside a body 10A made of metal and formed in a cylindrical shape, there is a high-pressure fluid chamber 2A that constitutes a high-pressure portion from the inlet of a fluid introduction passage 11 for introducing a high-pressure fluid to the valve portion of a pressure regulating valve 20A, a discharge pressure chamber 3A that constitutes a discharge pressure portion from the valve portion of the pressure regulating valve 20A to the discharge port of a fluid delivery passage 12 for discharging the decompressed and adjusted fluid, and a pressure control unit 4A provided with discharge pressure adjusting means for adjusting and maintaining the pressure of the discharged fluid.

[0024] The pressure regulating valve 20A is composed of a cylindrical member having an annular valve body 22A coaxially provided with a passage 27 through which fluid can pass, a valve shaft 21A disposed so as to be reciprocally movable in the axial direction, a donut-shaped valve seat 23A having a seat surface 24A with which the valve body 22A can be in close contact and forming a valve hole at the center, and discharge pressure adjusting means for adjusting the discharge pressure by reciprocally moving the valve shaft 21A to change the distance between the valve body 22A and the valve seat 23A.

[0025] The discharge pressure adjustment means is composed of an electric motor 30A having a rotor 31A, a driver 40A for driving and controlling the same, and a drive shaft 50A coaxially connected to the valve shaft 21A. The valve body 22A on the tip side of the valve shaft 21A is driven by the electric motor 30A whose drive is electronically controlled with respect to the seat surface 24A of the valve seat 23A, and is moved in the axial direction between a valve closing position where the valve body 22A and the seat surface 24A are in close contact and an open valve position where they are separated through a valve shaft movement structure 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, and the pressure of the discharged decompressed fluid is automatically adjusted so as to be equal to the set pressure while changing the opening area.

[0026] That is, while driving and controlling the electric motor 30A based on the data of the discharge pressure detected by a pressure sensor (not shown), by opening and closing the valve body 22A provided on the valve shaft 21A and adjusting the open valve position, a method of adjusting and maintaining the set discharge pressure is adopted. It can flexibly respond to fluctuations in the required flow rate and can automatically maintain various set discharge pressures. Note that as the electric motor 30A, an AC servo motor or a DC brushless motor is preferable from the viewpoint of adjustability.

[0027] And 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 body 10A, and a piston 37A that receives the fluid pressure in the discharge pressure chamber 3A is slidably disposed in the space together with the valve shaft 21A while being fixed to the outer peripheral side of the valve shaft 21A.

[0028] Thereby, when the valve is closed with the electric motor 30A stopped, since the fluid pressure on the discharge pressure chamber 3A side received by the piston 37A is converted into a pressure load in the direction of pressing the valve body 22A against the seat surface 24A, it is possible to prevent the occurrence of slow leakage through the pressure regulating valve 20A due to the reduction in the pressing force of the valve seat 23A against the seat surface 24A.

[0029] On the other hand, in the conventional electronically controlled regulator 1B described above, the feed screw 60 that constitutes its valve shaft movement structure has a backlash (play) X provided between the screw threads so that no jamming occurs when the trapezoidal female screw 62 and the trapezoidal male screw 61 mesh with each other as shown in FIG. 2. Therefore, when adjusting the pressure, the pressure regulating valve 20B shifts by the amount of backlash X according to the pressure balance between the high-pressure fluid chamber 2B and the discharge pressure chamber 3B, changing the valve opening area and causing a sudden change in the discharge pressure. However, in the electronically controlled regulator 1A of the present embodiment as well, since the feed screw 60 is similarly provided with backlash, the same problem is assumed to occur.

[0030] Therefore, in the present embodiment, a spring 70 is disposed in a compressed state in the space on the discharge pressure chamber 3A side where the piston 37A is disposed, and the tip side always urges the valve shaft 21A in the valve closing direction while contacting the pressure receiving surface side of the piston 37A. This is a feature of the present invention.

[0031] As a result, when the biasing force of the spring 70 is applied to the piston 37A, the trapezoidal female screw 62 and the trapezoidal male screw 61 that constitute the feed screw 60 are always in close contact and do not shift in the axial direction. Therefore, it is possible to prevent the valve shaft 21A from being displaced by the amount of backlash X provided in the feed screw 60 in advance, and it is possible to avoid a sudden change in the discharge pressure caused by the pressure balance between the high-pressure fluid chamber 2A and the discharge pressure chamber 3A.

[0032] As described above, with respect to the electronically controlled regulator, according to the present invention, in addition to preventing the occurrence of slow leakage through the pressure regulating valve when closing the valve, it is possible to avoid fluctuations in the discharge pressure caused by the backlash provided in the valve shaft movement structure.

Explanation of Reference Numerals

[0033] 1A Electronic control type regulator, 2A High-pressure fluid chamber, 3A Discharge pressure chamber, 4A Pressure control unit, 10A Body, 11 Fluid introduction path, 12 Fluid delivery path, 20A Pressure regulating valve, 21A Valve shaft, 22A Valve body, 23A Valve seat, 24A Seat surface, 27 Passage, 30A Electric motor, 31A Rotor, 37A Piston, 40A Driver, 50A Drive shaft, 60 Feed screw, 61 Trapezoidal male screw, 62 Trapezoidal female screw, 70 Spring

Claims

1. Inside a body having an inlet and an outlet, a valve shaft with a valve body coaxially provided and capable of reciprocating in the axial direction, a valve seat having a seat surface on the high-pressure fluid chamber side following the inlet where the valve body can be in close contact, and a valve shaft movement structure consisting of a feed screw provided between the outer peripheral surface of the valve shaft and the inner peripheral surface of a rotor by driving an electronically controlled electric motor, and a discharge pressure adjusting means for adjusting the fluid pressure by changing the distance between the valve body and the valve seat while reciprocating the valve shaft. The electronic control type regulator discharges the high-pressure fluid introduced into the high-pressure fluid chamber from the inlet as a decompressed fluid with a set pressure on the discharge pressure chamber side while decompressing and adjusting it with the pressure regulating valve. In this electronic control type regulator, a cylindrical space is formed in the discharge pressure chamber, and a piston that receives the fluid pressure in the discharge chamber pressure chamber is slidably disposed in the space together with the valve shaft while being fixed to the outer peripheral side of the valve shaft. A spring is disposed in the space that always biases the valve shaft in the valve closing direction while the tip side abuts against the piston. When the valve is closed with the electric motor stopped, in addition to the fluid pressure received by the piston being converted into a pressure load in the direction of pressing the valve body against the seat surface, during pressure regulation, the biasing force of the spring avoids the positional deviation of the valve shaft caused by the backlash provided at the meshing portion of the feed screw. An electronic control type regulator characterized by this.

2. The electric motor is an AC servo motor or a DC brushless motor. The valve shaft movement structure is a feed screw formed by a combination of a trapezoidal male screw formed on the outer peripheral surface of a cylindrical moving shaft attached coaxially to the valve shaft and a trapezoidal female screw formed on the inner peripheral surface of the rotor and meshing with the trapezoidal male screw. By driving the electric motor, the trapezoidal female screw rotates around the trapezoidal male screw, and the valve shaft is moved while operating in the axial direction without rotating the trapezoidal male screw. The electronic control type regulator according to Claim 1, characterized by this.

3. The valve shaft is composed of a cylindrical member having an annular valve body coaxially provided and having a passage through which fluid can pass. The discharge pressure of the fluid is adjusted by operating with the discharge pressure adjusting means so as to change the distance between the valve body on the tip side and the seat surface. The electronic control type regulator according to Claim 1 or 2, characterized by this.

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