Internal pressure control system

Abstract

To provide an internal pressure control system that can easily stabilize the behavior when controlling the internal pressure of a member having an internal chamber.SOLUTION: The control system 310 includes an on / off valve 307 arranged in a second guide passage 304 communicating with a first guide passage 303 connected to a gas supply source 302, a proportional control valve 1 arranged in a third guide passage 305 communicating with the first guide passage 303 and capable of controlling a smaller air flow rate than the on / off valve 307 by controlling its opening degree, a fourth guide passage 311 which guides air to the air spring 309 and communicates with the second guide passage 304 and the third guide passage 305, and a control device 315 which controls the air pressure in the internal chamber 309a to a target air pressure by controlling the opening degree of the proportional control valve 1 while controlling the on / off valve 307 to be open at a first timing and controlling the on / off valve 307 to be closed at a second timing after the first timing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an internal pressure control system, for example, an air spring control system or a tank internal pressure control system. [Background technology]

[0002] A conventional internal pressure control system is the air spring control system described in Patent Document 1. This air spring control system uses multiple on / off valves to adjust the internal pressure of the air springs of a railway vehicle, i.e., the height of the air springs, and ultimately adjusts the height of the railway vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-7371 Summary of the Invention [Problem to be solved by the invention]

[0004] When controlling the height of air springs in a railway vehicle using an on-off valve, the closing operation of the on-off valve can cause a rolling motion in which the car body sways, and it would be preferable to be able to suppress this rolling motion.Furthermore, regardless of the height control of the air springs in a railway vehicle, it would be preferable to be able to suppress vibrations when controlling the internal pressure of a component having an internal chamber to a target value, in order to suppress the generation of abnormal noise, etc.Therefore, an object of the present disclosure is to provide an internal pressure control system that easily stabilizes behavior when controlling the internal pressure of a component having an internal chamber. [Means for solving the problem]

[0005] In order to solve the above problems, the internal pressure control system according to the present disclosure includes a first guide passage that guides gas from a gas supply source, a first branch section that branches the first guide passage into a second guide passage and a third guide passage, an on / off valve arranged in the second guide passage, a proportional control valve that is arranged in the third guide passage and that can control the flow rate per unit time of gas that is less than the flow rate per unit time of gas that can pass through the on / off valve by controlling its opening, a fourth guide passage that guides gas to an internal chamber of a member, a second branch section that branches the fourth guide passage to the side of the second guide passage opposite the first branch section side of the on / off valve and to the side of the third guide passage opposite the first branch section side of the proportional control valve, and a control device that controls the air pressure in the internal chamber to a target air pressure by controlling the opening of the proportional control valve at a first timing to open the on / off valve and at a second timing that is later than the first timing to close the on / off valve.

[0006] If the component is an air spring, controlling the air pressure in the internal chamber of the air spring to a target air pressure includes controlling the height of the air spring to a target height. Furthermore, if air springs are disposed on both sides of the vehicle in the width direction, controlling the air pressure in the internal chamber of the air spring to a target air pressure includes controlling the height difference between the air springs on both sides of the vehicle in the width direction to a target height difference. In such a case, the target height difference may be determined based on the inclination angle of the vehicle relative to the horizontal plane.

[0007] According to the present disclosure, an on / off valve and a proportional control valve are arranged in parallel between a gas supply source and an internal chamber of a component, and the on / off valve is controlled to be open at an initial timing, while at a final timing, the air pressure in the internal chamber is controlled to a target air pressure by controlling the opening of the proportional control valve with the on / off valve controlled to be closed.

[0008] Therefore, a large amount of gas can be supplied to the internal chamber via the on / off valve at the initial timing, and the responsiveness when controlling the air pressure in the internal chamber to the target air pressure can be improved. In addition, since the air pressure can be adjusted with high accuracy at the final timing, it is easy to perform control that is less likely to cause vibration at the final timing of the air pressure adjustment.

[0009] In addition, a two-way shutoff valve may be arranged between the member and the second branch portion in the fourth guide passage, or a two-way shutoff valve may be arranged between the on / off valve and the second branch portion in the second guide passage.

[0010] According to the above configuration, the number of two-way shutoff valves can be reduced, and the internal pressure control system can be configured compactly.

[0011] Furthermore, at the first timing, the opening of the proportional control valve may be greater than 0 opening.

[0012] According to the above configuration, the opening of the proportional control valve can be continuously controlled at a non-zero value at the timing connecting the first timing and the second timing, and gas that has passed through the proportional control valve is supplied to the internal chamber at both the first timing and the second timing, thereby enabling a smooth transition from the first timing to the second timing.

[0013] Furthermore, when the control device determines that the air pressure in the internal chamber has reached a predetermined percentage of the target air pressure, the timing may be switched from the first timing to the second timing.

[0014] According to the above configuration, the behavior of the member having an internal chamber when controlling the internal pressure can be easily stabilized by simple control.

[0015] Furthermore, the member may be an air spring, and the switching from the first timing to the second timing may be performed based on a physical quantity related to the height of the air spring.

[0016] According to the above configuration, it is easy to stabilize the behavior when controlling the height of the air spring, and when the air spring is mounted on a railway car body, it is easy to suppress the rolling motion of the car body. [Effects of the Invention]

[0017] According to the internal pressure control system according to the present disclosure, it is easy to stabilize the behavior when controlling the internal pressure of a member having an internal chamber. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram of an air spring height control system, which is an embodiment of an internal pressure control system according to the present disclosure. [Figure 2] FIG. 1 is a pneumatic circuit diagram of an air spring height control system. [Figure 3] 1 is a diagram for explaining air pressure control in the internal chamber of an air spring in an air spring height control system. FIG. [Figure 4] 4 is a flowchart showing an example of a control procedure when the control device increases the air pressure in the internal chamber of the air spring to a target air pressure. [Figure 5] 1 is a diagram showing a main part of a proportional control valve according to a first embodiment of the present disclosure. FIG. [Figure 6] 4 is a schematic plan view of the valve body as viewed from the other axial side. FIG. [Figure 7] FIG. 2 is an enlarged cross-sectional view of the proportional control valve and its surroundings. [Figure 8] 1 is a plan view of an end face of a case having a communication port and a valve seat, as viewed from one axial side. FIG. [Figure 9] FIG. 8 is an enlarged cross-sectional view of a proportional control valve according to a modified example, corresponding to FIG. 7. [Figure 10] FIG. 6 is a cross-sectional view corresponding to FIG. 5 of a proportional control valve according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that, when multiple embodiments or variations are included below, it is anticipated from the beginning that new embodiments can be constructed by appropriately combining their characteristic features. In the following examples, the same components are designated by the same reference numerals in the drawings, and redundant explanations will be omitted. The drawings include schematic diagrams, and the dimensional ratios of the length, width, height, etc. of each component between different drawings do not necessarily match. Among the components described below, components not recited in the independent claims representing the highest concepts are optional components and not essential components.

[0020] Fig. 1 is a schematic diagram of an air spring height control system 310, which is one embodiment of an internal pressure control system according to the present disclosure, and Fig. 2 is a pneumatic circuit diagram of the air spring height control system 310. The air spring height control system (hereinafter simply referred to as the control system) 310 is mounted on, for example, a railway vehicle (hereinafter simply referred to as the car body) 321. More specifically, the air spring 309 of the control system 310 shown in Figs. 1 and 2 is arranged on one widthwise side and below the car body 321 (not shown). The control device 315 not only controls the various valves 1, 307, and 313 provided in the control system 310, but also controls various valves (not shown) of the control system (not shown) including the air spring (not shown) arranged on the other widthwise side and below the car body 321.

[0021] That is, control device 315 is shared and used by control system 310 and other control systems (not shown). The other control systems (not shown) are the same as control system 310, which will be described in detail below. Control device 315 performs feedback control of the height difference between air springs 309 on both sides in the vehicle width direction. This feedback control of the height difference is performed by control device 315 based on signals from height detection sensors 319 provided in each control system 310.

[0022] The control device 315 may calculate the inclination angle of the vehicle 321 with respect to the horizontal plane based on signals from two height detection sensors 319 installed on both sides of the vehicle body 321 in the width direction, and control the various valves 1, 307, 313 provided in the control system 310 based on the calculated inclination angle. By controlling the height difference between the air springs 309 on both sides of the vehicle body to a target value, the ride comfort when cornering the vehicle body 321 is improved.

[0023] As shown in FIGS. 1 and 2 , the control system 310 includes a first guide passage 303, a second guide passage 304, and a third guide passage 305 that guide gas from a gas supply source 302, a first branch section 306 that branches the first guide passage 303 into the second guide passage 304 and the third guide passage 305, an on / off valve 307 disposed in the second guide passage 304, and a proportional control valve 1 disposed in the third guide passage 305. In this embodiment, the gas is air, but the gas may be a gas other than air. The gas supply source 302 includes, for example, an air compressor and discharges compressed air. By controlling the opening of the proportional control valve 1, the flow rate per unit time of air that is smaller than the flow rate per unit time of air that can pass through the on / off valve 307 can be controlled.

[0024] The control system 310 further includes an air spring 309 as an example of a component having an internal chamber 309a, a fourth guide passage 311 that guides gas into the internal chamber 309a of the air spring 309, a second branch portion 312 that branches the fourth guide passage 311 into a second guide passage 304 and a third guide passage 305, a two-way cutoff valve 313 disposed in the fourth guide passage 311, and a control device 315 that controls the on-off valve 307, the proportional control valve 1, and the two-way cutoff valve 313. The air spring 309 is a spring device that utilizes the elasticity of compressed air. The second branch portion 312 branches an end of the fourth guide passage 311 opposite the air spring 309 side to an end of the second guide passage 304 opposite the first branch portion 306 side of the on-off valve 307 and an end of the third guide passage 305 opposite the first branch portion 306 side of the proportional control valve 1.

[0025] The on-off valve 307 can be in either a closed state or an open state. The valve opening of the on-off valve 307 can only be in two positions: fully open or fully closed. The on-off valve 307 may be realized by any known configuration, such as a solenoid valve or an electric valve. As shown in FIG. 2, air flows through the on-off valve 307 from the gas supply source 302 side to the air spring 309 side.

[0026] Proportional control valve 1 is a 3-1 three-way valve. Specifically, proportional control valve 1 can be selectively placed in a first position where all three inlets are blocked, a second position where first inlet 1a, which connects to first branch portion 306, is connected to second inlet 1b, which connects to second branch portion 312, and a third position where second inlet 1b is connected to third inlet 1c, which connects to an exhaust path. As will be described in detail with reference to Figure 5 and subsequent figures, the flow rate of gas per unit time flowing through proportional control valve 1 in the second position can be precisely adjusted, and the flow rate of gas per unit time flowing through proportional control valve 1 in the third position can also be precisely adjusted.

[0027] In this embodiment, the flow rate of air that can pass through the on-off valve 307 per unit time when the on-off valve 307 is controlled to be fully open is greater than the flow rate that can pass through the proportional control valve 1 per unit time when the opening of the proportional control valve 1 is controlled to be fully open. However, the flow rate of air that can pass through the on-off valve 307 per unit time when the on-off valve 307 is controlled to be fully open may be equal to or less than the flow rate that can pass through the proportional control valve 1 per unit time when the opening of the proportional control valve 1 is controlled to be fully open.

[0028] The two-way shutoff valve 313 can be in either a closed state or an open state. The valve opening of the two-way shutoff valve 313 can only be in two positions: fully open or fully closed. When the two-way shutoff valve 313 is fully open, gas can flow through the two-way shutoff valve 313 in either direction. The two-way shutoff valve 313 may be realized in any known configuration, such as a solenoid valve or an electric valve. The air control device disclosed in Japanese Patent Application Laid-Open No. 2023-36304 may be used as the two-way shutoff valve 313.

[0029] The control device 315 is preferably configured by a computer, for example, a microcomputer, and includes a control unit 315a and a storage unit 315b. The control unit 315a, i.e., the processor, includes, for example, a CPU (Central Processing Unit). The storage unit 315b is configured by a hard disk drive (HDD), a solid state drive (SSD), or the like, and may include a nonvolatile memory such as a ROM (Read Only Memory) or a volatile memory such as a RAM (Random Access Memory). The storage unit 315b may be configured by only one storage medium, or may be configured by multiple different storage media. The CPU reads and executes programs and the like stored in the storage unit 315b. The nonvolatile memory stores control programs, predetermined thresholds, and the like in advance. The volatile memory temporarily stores the read programs and processing data.

[0030] 2, the control system 310 may include one or more filters 317. For example, as shown in FIG. 2, the control system 310 may include a first filter 317a disposed in the first guide passage 303 and a second filter 317b disposed in the fourth guide passage 311 between the two-way shutoff valve 313 and the air spring 309, which may suppress or prevent foreign matter such as dust from entering the various valves 1, 307, 313 or the air spring 309. In addition, the exhaust path connected to the third inlet 1c may include a silencer 318, which may suppress or prevent abnormal noise from being generated during the exhaust of air.

[0031] Fig. 3 is a diagram illustrating the air pressure control of internal chamber 309a of air spring 309 in control system 310, and Fig. 4 is a flowchart showing an example of a control procedure when control device 315 increases the air pressure in internal chamber 309a of air spring 309 to a target air pressure. The air pressure control of internal chamber 309a of air spring 309 in control system 310 corresponds one-to-one with and is consistent with the height control of air spring 309 in control system 310. Control device 315 can identify the height position of air spring 309, i.e., the air pressure in internal chamber 309a of air spring 309, based on a signal from height detection sensor 319.

[0032] 3, assume that at time T1 when the air pressure in internal chamber 309a is at P1, target air pressure P3 is set based on the track route, vehicle speed, etc. Then, as shown in FIG. 4, in step S1, control device 315 fully opens on / off valve 307 and controls proportional control valve 1 to the second position, and then controls the opening in the second position to fully open. Furthermore, substantially simultaneously with this control, control is made to fully open bidirectional cutoff valve 313.

[0033] By this control, compressed air discharged from gas supply source 302 is supplied into internal chamber 309a of air spring 309 via first guide passage 303, second guide passage 304, third guide passage 305, and fourth guide passage 311, causing the air pressure in internal chamber 309a to increase and the height of air spring 309 to increase. This control is performed during the first timing. In step S2, control device 315 determines, based on a signal from height detection sensor 319, whether the air pressure in internal chamber 309a has reached or exceeded control switchover pressure P2.

[0034] The control device 315 can determine the control switchover pressure P2 based on the target pressure P3, and may calculate the control switchover pressure P2 based on the target pressure P3 and a program stored in the memory unit 315b that calculates the control switchover pressure P2 from the target pressure P3. The control device 315 may determine that the pressure in the internal chamber 309a has reached or exceeded the control switchover pressure P2 when it determines that the pressure in the internal chamber 309a has reached a predetermined percentage of the target pressure P3. The predetermined percentage may be set to, for example, a percentage ranging from 80% to 95% of the target pressure P3.

[0035] If a negative determination is made in step S2, step S2 is repeated. On the other hand, if a positive determination is made in step S2, the process proceeds to step S3, where the control device 315 fully closes the on / off valve 307 while maintaining the proportional control valve 1 and the two-way cutoff valve 313 fully open. This control switches the first timing to the second timing at time T2 in FIG. 3.

[0036] In step S4 after step S3, the on / off valve 307 is maintained fully closed, and the two-way cutoff valve 313 is maintained fully open. Then, as time passes, the proportional control valve 1 is controlled to gradually decrease in opening. In the following step S5, the control device 315 determines, based on a signal from the height detection sensor 319, whether the air pressure in the internal chamber 309a has reached the target air pressure P3.

[0037] If a negative determination is made in step S5, step S5 is repeated. On the other hand, if a positive determination is made in step S5, the process proceeds to step S6, where at time T3 in FIG. 3, the control device 315 switches the aperture of the two-way shutoff valve 313 to fully closed. This maintains the state in which the air pressure in the internal chamber 309a is equal to the target air pressure P3. When step S6 is completed, the control ends. Note that control may be performed to continuously and gradually decrease the aperture of the proportional control valve 1 over the entire range of the second timing. Furthermore, the second timing may include a timing in which the aperture of the proportional control valve 1 continuously and gradually decreases over time and is shorter than the second timing. Furthermore, during the second timing, the aperture of the proportional control valve 1 may be gradually decreased over time, or the short-term flow rate of air passing through the proportional control valve 1 may be decreased in a stepped manner over time.

[0038] When exhausting the air inside air spring 309, control device 315 controls the opening of two-way cutoff valve 313 to fully open and controls the opening of on / off valve 307 to fully closed. Control device 315 also controls proportional control valve 1 to a state in which second inlet 1b is connected to third inlet 1c. The opening when connecting second inlet 1b to third inlet 1c is set appropriately based on specifications, etc., and is set to fully open, for example. By controlling in this manner, air that has flowed from internal chamber 309a of air spring 309 through second branch portion 312 to proportional control valve 1 can be exhausted to the outside via an exhaust path connected to third inlet 1c.

[0039] Although not shown, instead of disposing the two-way cutoff valve 313 between the second branch portion 312 and the air spring 309, the two-way cutoff valve 313 may be disposed in the second guide passage 304 between the on-off valve 307 and the second branch portion 312. The on-off valve 307 may be selectively movable between a first position, which connects the first branch portion 306 and the two-way cutoff valve 313, and a second position, which connects the two-way cutoff valve 313 to the exhaust path. In this case, a silencer 320, shown by a dotted line, may be disposed in the exhaust path. In this case, exhaust via the on-off valve 307 becomes possible in addition to exhaust via the proportional control valve 1, thereby shortening the time required for exhaust and improving exhaust response.

[0040] As described above, the control system 310 includes a first guide passage 303 that guides air from a gas supply source 302, a first branch section 306 that branches the first guide passage 303 into a second guide passage 304 and a third guide passage 305, an on / off valve 307 arranged in the second guide passage 304, and a proportional control valve 1 that is arranged in the third guide passage 305 and that can control the flow rate per unit time of gas that is less than the flow rate per unit time of gas that can pass through the on / off valve 307 by controlling its opening degree. The control system 310 also includes a fourth guide passage 311 that guides air to the internal chamber 309a of the air spring 309, a second branch section 312 that branches off the fourth guide passage 311 to the side opposite the first branch section 306 of the on / off valve 307 in the second guide passage 304 and to the side opposite the first branch section 306 of the proportional control valve 1 in the third guide passage 305, and a control device 315 that controls the air pressure in the internal chamber 309a to a target air pressure by controlling the opening of the proportional control valve 1 while controlling the on / off valve 307 to be open at a first timing and controlling the on / off valve 307 to be closed at a second timing that is later than the first timing.

[0041] Note that controlling the air pressure in internal chamber 309a of air spring 309 to a target air pressure includes controlling the height of air spring 309 to a target height. Furthermore, when air springs 309 are arranged on both sides of car body 321 in the width direction, controlling the air pressure in internal chamber 309a of air spring 309 to a target air pressure includes controlling the height difference between air springs 309 on both sides of car body 321 in the width direction to a target height difference. In such a case, the target height difference may be determined based on the tilt angle of car body 321 with respect to the horizontal plane detected by an encoder.

[0042] According to the present disclosure, an on / off valve 307 and a proportional control valve 1 are arranged in parallel between a gas supply source 302 and an internal chamber 309a of an air spring 309, and the on / off valve 307 is controlled to be open at an initial timing, while at a final timing, the air pressure in the internal chamber 309a is controlled to a target air pressure by controlling the opening of the proportional control valve 1 with the on / off valve 307 controlled to be closed.

[0043] Therefore, a large amount of gas can be supplied to internal chamber 309a via on / off valve 307 at an initial timing, and excellent responsiveness can be achieved when controlling the air pressure in internal chamber 309a to target air pressure P3. Furthermore, since the air pressure can be adjusted with high precision at the final timing, it is easy to perform control that makes it difficult for vibration to occur in air spring 309 at the final timing of air pressure adjustment. As a result, in this embodiment, rolling motion of vehicle body 321 can be effectively suppressed at the final timing of air pressure adjustment.

[0044] In addition, a two-way shutoff valve 313 may be arranged between the air spring 309 and the second branch portion 312 in the fourth guide passage 311, or a two-way shutoff valve 313 may be arranged between the on / off valve 307 and the second branch portion 312 in the second guide passage 311.

[0045] According to the above configuration, the number of two-way cutoff valves 313 can be reduced, and the control system 310 can be configured compactly.

[0046] At the first timing, the opening degree of the proportional control valve 1 may be greater than 0 opening degree.

[0047] According to the above configuration, the opening of the proportional control valve 1 can be continuously controlled at a non-zero value at the timing connecting the first timing and the second timing, and gas is supplied to the internal chamber via the proportional control valve 1 at both the first timing and the second timing. Therefore, the transition from the first timing to the second timing can be performed smoothly.

[0048] Furthermore, when the control device 315 determines that the air pressure in the internal chamber 309a has reached a predetermined percentage of the target air pressure, the timing may be switched from the first timing to the second timing.

[0049] According to the above configuration, the behavior of air spring 309 when controlling the internal pressure of internal chamber 309a can be easily stabilized by simple control.

[0050] Alternatively, switching from the first timing to the second timing may be performed based on a physical quantity related to the height of air spring 309. The above configuration makes it easy to stabilize the behavior when controlling the height of air spring 309. Note that the physical quantity related to the height of air spring 309 naturally includes the height of air spring 309 itself, and also the internal pressure of internal chamber 309a of air spring 309.

[0051] The present disclosure is not limited to the above-described embodiment and its modifications, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents. For example, in the above-described embodiment, control system 310 controls the air pressure in internal chamber 309a of air spring 309, but the control system may control the air pressure in the internal chamber of any member other than air spring 309, such as the air pressure in the internal chamber of a tank.

[0052] An example configuration of the proportional control valve 1 will be described below with reference to Figures 5 to 10. Figure 5 is a diagram showing the main parts of the proportional control valve 1 according to the first embodiment of the present disclosure. As shown in Figure 5, the proportional control valve 1 includes a case 5, a shaft member 10, a valve body 30, and an advance / retreat drive mechanism 50. The shaft member 10 includes a first passage 6, which is an internal passage that opens to an end face 11 on at least one axial side (the left side in Figure 5). The first passage 6 includes a first opening 12 that communicates with the end face 11, as well as a second opening 16 that communicates with the outer peripheral surface of the shaft member 10.

[0053] The case 5 defines a valve element accommodating chamber 21 and a shaft member accommodating chamber 22. In other words, the case 5 has the valve element accommodating chamber 21 and the shaft member accommodating chamber 22 inside. The valve element accommodating chamber 21 accommodates the valve element 30, and the shaft member 10 is accommodated in the shaft member accommodating chamber 22 so as to be slidable in the axial direction. The shaft member 10 includes a cylindrical outer peripheral surface, and at least a portion of the outer peripheral surface of the shaft member accommodating chamber 22 is configured as a cylindrical inner peripheral surface. The cylindrical outer peripheral surface of the shaft member 10 is supported in the radial direction by the cylindrical inner peripheral surface of the shaft member accommodating chamber 22. This allows the shaft member 10 to slide relative to the shaft member accommodating chamber 22 only in the axial direction of the shaft member 10. The shaft member accommodating chamber 22 has a communication port 28 that communicates with the valve element accommodating chamber 21 and is open in the axial direction. As will be described in detail later, the annular edge of the communication port 28 is included in a valve seat 65 that closes the communication port 28 when the valve body 30 comes into contact with it.

[0054] The case 5 defines a second passage 15, a third passage 17, and a fourth passage 19. In other words, the second passage 15, the third passage 17, and the fourth passage 19 are provided in the case 5. The second passage 15 has a port 15a that communicates with the outside, and this port 15a is connected to a gas supply source, for example, directly or indirectly via an air guide passage to an air discharge port of an air supply source that has a compressor and discharges compressed air. Meanwhile, the end of the second passage 15 opposite to the port 15a opens into and communicates with the valve element accommodating chamber 21.

[0055] The third passage 17 has a port 17a that communicates with the outside. The end of the third passage 17 opposite the port 17a opens to and communicates with the shaft member accommodating chamber 22. The shaft member accommodating chamber 22 has an annular recess 63, and the annular recess 63 and the outer peripheral surface of the shaft member 10 define an annular first gas accommodating chamber 25. A second opening 16 of the first passage 6 provided inside the shaft member 10 communicates with the first gas accommodating chamber 25 when the shaft member 10 is located within a predetermined axial range. The fourth passage 19 has a port 19a that opens to the outside. The end of the fourth passage 19 opposite the port 19a opens to and communicates with the first gas accommodating chamber 25. As a result, the first passage 6 communicates with the fourth passage 19 via the first gas accommodating chamber 25 when the shaft member 10 is located within the predetermined axial range.

[0056] 6 is a schematic plan view of the valve element 30 as viewed from the other axial side. As shown in FIG. 6, the valve element accommodating chamber 21 has a cylindrical inner circumferential surface 21a. The valve element 30 has a central axis, and when the valve element 30 is accommodated in the valve element accommodating chamber 21, the central axis is approximately collinear with the central axis of the cylindrical inner circumferential surface 21a and is also approximately collinear with the central axis of the cylindrical inner circumferential surface of the shaft member accommodating chamber 22. When the valve element 30 is accommodated in the valve element accommodating chamber 21, the central axis of the valve element 30 is approximately collinear with the central axis of the shaft member 10 accommodated in the shaft member accommodating chamber 22.

[0057] The valve element 30 has a metal main body 60 and a disk-shaped disk portion 61 made of an elastic material, such as rubber. The disk portion 61 is an example of a portion of the valve element 30 that contacts a valve seat 65. The disk portion 61 is fitted into and fixed in a disk-shaped recess provided in the center of the main body 60. The outer edge 60a of the main body 60 has a wave shape, and on the outer edge 60a of the main body 60, protrusions 60b that contact the cylindrical inner circumferential surface 21a and recesses 60c that face the cylindrical inner circumferential surface 21a in the radial direction and are spaced apart from each other appear alternately in the circumferential direction.

[0058] As will be described in detail later, when the shaft member 10 is out of contact with the valve body 30, the rubber disc portion 61 is seated on the annular valve seat 65. By seating the other axial surface of the rubber disc portion 61 on the valve seat 65, the communication port is blocked and gas cannot flow between the valve body accommodating chamber 21 and the shaft member accommodating chamber 22.

[0059] As shown in Fig. 5, the proportional control valve 1 further includes a biasing member that applies a force to the valve element 30 in the other axial direction. In this embodiment, the biasing member is configured as a coil spring 67. The coil spring 67 extends in the axial direction. The other axial end of the coil spring 67 contacts the end face 47 on one axial side of the valve element 30, and the one axial end of the coil spring 67 contacts the inner surface portion 45 on the other axial side of the valve element accommodating chamber 21.

[0060] The coil spring 67 biases the valve element 30 toward the other axial side (the right side in FIG. 5 ) relative to the case 5. By providing the coil spring 67, when the shaft member 10 is not in contact with the valve element 30, the disc portion 61 can be seated on the valve seat 65 regardless of the air pressure in the valve element accommodating chamber 21. Furthermore, by providing the coil spring 67, the position of the valve element 30 can be stabilized when the valve element 30 moves in the axial direction, allowing the valve element 30 to move smoothly back and forth in the axial direction. The end of the coil spring 67 on the other axial side may or may not be fixed to the end face 47 on one axial side of the valve element 30. Furthermore, the proportional control valve does not need to have a biasing member accommodated in the valve element accommodating chamber.

[0061] 5, the advance / retract drive mechanism 50 includes a first coil 71 located radially outward of the shaft member 10 so as to surround at least a portion of the shaft member 10, and a second coil 72 located radially outward of the shaft member 10 so as to surround at least a portion of the shaft member 10, and disposed axially spaced apart from the first coil 71. The advance / retract drive mechanism 50 also includes a permanent magnet 73 located axially between the first coil 71 and the second coil 72, and positioned radially outward of the shaft member 10.

[0062] The advance / retract drive mechanism 50 includes an inner yoke 77 having an outer peripheral surface 77a around which the first coil 71 and the second coil 72 are wound, and an outer yoke 78 having an inner peripheral surface that faces the first coil 71 and the second coil 72 in the radial direction and positioned radially outward from the first coil 71 and the second coil 72. The outer peripheral surface 77a is preferably configured as a cylindrical outer peripheral surface. The advance / retract drive mechanism 50 further includes a pair of connecting yokes 79 that connect both axial end portions of the inner yoke 77 to both axial end portions of the outer yoke 78.

[0063] The first coil 71 and the second coil 72 are connected in series and wound in opposite directions. The shaft member 10 has a large diameter portion 13 and a small diameter portion 14 whose outer diameter is smaller than that of the large diameter portion 13. The shaft member 10 has a flange 75 that protrudes radially outward from the small diameter portion 14 within a predetermined range in the axial direction. The large diameter portion 13 is formed by providing the flange 75. It is preferable that the outer peripheral surface of the large diameter portion 13, i.e., the outer peripheral surface of the flange 75, be a cylindrical outer peripheral surface.

[0064] The shaft member 10 has annular step portions 18a, 18b in its small diameter portion located on both axial sides of the large diameter portion 13. The advance / retract drive mechanism 50 also includes a first first biasing member 31 and a second first biasing member 32 that bias the shaft member 10 in the axial direction. The advance / retract drive mechanism 50 also includes a first second biasing member 33 and a second second biasing member 34 for centering the shaft member 10 in the radial direction. The advance / retract drive mechanism 50 also includes a first annular washer 35 and a second annular washer 36 for preventing the second biasing members 33, 34 from coming off the shaft member 10.

[0065] More specifically, the first first biasing member 31 and the second first biasing member 32 are disposed opposite each other in the axial direction with the large diameter portion 13 sandwiched therebetween. The first first biasing member 31 is a coil spring, and is disposed so as to surround the small diameter portion 14. An end portion on one axial direction of the first first biasing member 31 contacts a wall surface that extends in the radial direction of the case 5, and an end portion on the other axial direction of the first first biasing member 31 contacts an annular end face on one axial direction side of the large diameter portion 13.

[0066] The second first biasing member 32 is a coil spring and is arranged to surround the small diameter portion 14. An end portion on the other axial direction of the second first biasing member 32 contacts a radially extending wall surface of the case 5, and an end portion on one axial direction of the second first biasing member 32 contacts an annular end surface on the other axial direction of the large diameter portion 13. Each of the first biasing members 31, 32 has a natural length in a first position described below. In other words, each of the first biasing members 31, 32 biases the shaft member 10 toward the first position. Note that the first first biasing member 31 and the second first biasing member 32 may apply axial forces of the same magnitude but in opposite directions to the large diameter portion 13 in the first position.

[0067] The first second biasing member 33 is an annular leaf spring, and the shaft member 10 passes through a through hole of the first second biasing member 33. The first second biasing member 33 is fitted onto and fixed to the outer cylindrical peripheral surface of the shaft member 10. The first second biasing member 33 is fitted axially slidably into the cylindrical inner peripheral surface of the case 5, and receives a radially inward force from the cylindrical inner peripheral surface of the case 5. An end face on the other axial side of the radially inner end of the first second biasing member 33 abuts against the annular step portion 18a of the shaft member 10. A first washer 35 is press-fitted onto one axial side of the first second biasing member 33 in the shaft member 10, and an end face on one axial side of the radially inner end of the first second biasing member 33 abuts against an end face on the other axial side of the first washer 35.

[0068] The second second biasing member 34 is an annular leaf spring, and the shaft member 10 passes through a through hole in the second second biasing member 34. The second second biasing member 34 is fitted onto and fixed to the outer cylindrical peripheral surface of the shaft member 10. The second second biasing member 34 is fitted axially slidably into the cylindrical inner peripheral surface of the case 5, and receives a radially inward force from the cylindrical inner peripheral surface of the case 5. An end face on one axial side of the radially inner end of the second second biasing member 34 abuts against the annular step portion 18b of the shaft member 10. A second washer 36 is press-fitted onto the other axial side of the second second biasing member 34 on the shaft member 10, and an end face on the other axial side of the radially inner end of the second second biasing member 34 abuts against an end face on one axial side of the second washer 36. The second biasing members 33, 34 are provided to center the shaft member 10 in the radial direction and to allow the shaft member 10 to slide smoothly in the axial direction.

[0069] In this embodiment, the advance / retract drive mechanism 50 includes a first first biasing member 31 and a second first biasing member 32, but the advance / retract drive mechanism does not necessarily have to include the first first biasing member 31 and the second first biasing member 32, and may instead include only one biasing member that biases the shaft member to the first position. Alternatively, the advance / retract drive mechanism does not necessarily have to include a mechanical spring that biases the shaft member to the first position, and may instead be biased by only a magnetic spring. Furthermore, the advance / retract drive mechanism 20 includes a first second biasing member 33 and a second second biasing member 34 for centering the shaft member 10, but the advance / retract drive mechanism does not necessarily have to include a biasing member for centering the shaft member.

[0070] Next, the structure and operation of the valve element 30 and the valve seat 65 will be described. FIG. 7 is an enlarged cross-sectional view of the valve element 30 and its surroundings in the proportional control valve 1. As shown in FIG. 7, the shaft member accommodating chamber 22 has a cylindrical inner circumferential surface 22a at one axial end on the communication port 28 side. The central axis of this cylindrical inner circumferential surface 22a substantially coincides with the central axis of the shaft member 10, and the inner diameter of the cylindrical inner circumferential surface 22a is larger than the outer diameter of the cylindrical outer circumferential surface 10a at one axial end of the shaft member 10. As a result, an annular flow path 64 exists between the cylindrical inner circumferential surface 22a and the cylindrical outer circumferential surface 10a. The shaft member accommodating chamber 22 has a second gas accommodating chamber 29 formed by an annular recess. The annular flow path 64 is in communication with the second gas accommodating chamber 29, and the third passage 17 is also in communication with the second gas accommodating chamber 29.

[0071] The shaft member accommodating chamber 22 has an annular O-ring accommodating recess 53 located axially between the first gas accommodating chamber 25 and the second gas accommodating chamber 29 and spaced apart from both the first gas accommodating chamber 25 and the second gas accommodating chamber 29. An O-ring 54 is accommodated in the O-ring accommodating recess 53 and is in contact with both the outer circumferential surface of the shaft member 10 and the bottom surface of the O-ring accommodating recess 53 and is elastically deformed in the radial direction. This O-ring 54 is provided to prevent gas from flowing from the first gas accommodating chamber 25 to the second gas accommodating chamber 29 through the gap between the inner circumferential surface of the shaft member accommodating chamber 22 and the outer circumferential surface of the shaft member 10.

[0072] Next, the structure of the valve seat 65 will be described in detail. As shown in Fig. 7, the valve seat 65 includes an annular first portion 81 having tips with approximately the same height, and a second portion 82 having a tip lower than the first portion 81 and positioned radially outward of the first portion 81. Fig. 8 is a plan view of the end face 39 (see Fig. 7) of the case 5 having the communication port 28 and the valve seat 65, as viewed from one axial side. As shown in Fig. 8, the end face 11 on one axial side of the shaft member 10 has a circular planar shape, and the first opening 12 of the first passage 6 also has a circular planar shape and is provided at the radial center of the end face 11.

[0073] In the plan view of Figure 8, the first portion 81 has an annular planar shape and faces the cylindrical outer peripheral surface 10a of the shaft member 10 in the radial direction at a distance. The second portion 82 is disposed at a distance from the first portion 81 in the radial direction. The tip surface of the first portion 81 is configured as a plane that is approximately perpendicular to the axial direction, and the tip surface of the second portion 82 is also configured as a plane that is approximately perpendicular to the axial direction. The second portion 82 includes a plurality of circumferentially extending portions 40, 41 that are disposed at a distance from each other in the radial direction and extend in the circumferential direction. An annular groove 74 exists between the radially adjacent circumferentially extending portions 40, 41.

[0074] Each circumferentially extending portion 40, 41 has a structure in which a plurality of radially extending grooves 90, 91, which extend radially and have both ends open radially, are provided at intervals in the circumferential direction on a ring-shaped protrusion whose tip end surface is formed by a plane substantially perpendicular to the axial direction. The radially extending grooves 90, 91 are preferably arranged at equal intervals in the circumferential direction, but may be arranged at non-equidistant intervals in the circumferential direction. Alternatively, at least one circumferentially extending portion may have a structure in which a single radially extending groove, which extends radially and has both ends open radially, is provided on a ring-shaped protrusion whose tip end surface is formed by a plane substantially perpendicular to the axial direction. As shown in FIG. 8 , the central axes of the ring-shaped first portion 81, the shaft member 10, and the communication port 28 are preferably aligned on the same straight line. It is also preferable that the central axes, which are the basis for the radii of curvature of each of the circumferentially extending portions 40, 41, are also aligned on the same straight line.

[0075] In the above configuration, the proportional control valve 1 operates as follows. Assume that the port 15a of the second passage 15 is connected to a gas supply source, and the port 17a of the third passage 17 and the port 19a of the fourth passage 19 are also connected to predetermined ports of a gas control device (not shown), rendering the proportional control valve 1 operable. Referring to FIG. 5 , if neither the first coil 71 nor the second coil 72 is energized, the magnetic circuits generated by the permanent magnet 73 cancel each other out on one axial side and the other axial side of the permanent magnet 73. Therefore, the magnetic force of the permanent magnet 73 attracted to the large-diameter portion 13 and the biasing force applied to the shaft member 10 by the first biasing members 31 and 32 position the shaft member 10 in a first position where the large-diameter portion 13 faces the permanent magnet 73 in the radial direction. In the first position, the valve element 30 is seated on the valve seat 65, and the end face 11 of the shaft member 10 contacts the valve element 30. Therefore, since both the communication port 28 and the first opening 12 of the first passage 6 are closed by the valve body 30, the second passage 15 is not connected to both the first passage 6 and the third passage 17, and the third passage 17 is not connected to the first passage 6.

[0076] Next, assume that a current is passed through the first coil 71 and the second coil 72, which are connected in series, from the first axial side to the second axial side. In this case, because the first coil 71 and the second coil 72 are wound in opposite directions around the outer peripheral surface 77a of the inner yoke 77, the magnetic fields generated by the first coil 71 and the second coil 72 reinforce each other, resulting in a magnetic field that is stronger on the first axial side than on the second axial side, for example, and as a result, the shaft member 10 moves to the first axial side.

[0077] The following describes a case where the first axial side coincides with one axial side. In this case, the shaft member 10 moves in the one axial direction, and the end face 11 of the shaft member 10 presses the valve element 30 in the one axial direction, causing the valve element 30 to move in the one axial direction. Then, as shown in FIG. 7, the valve element 30 moves away from the valve seat 65, opening the communication port 28. Then, gas (e.g., air) supplied from the second passage 15 to the valve element accommodating chamber 21 passes between the cylindrical inner circumferential surface 21a (see FIG. 6) and the recess 60c, passes through the communication port 28, and further passes through the annular flow path 64 (see FIG. 7) and the second gas accommodating chamber 29 to flow through the third passage 17 toward the port 17a. At this time, because the end face 11 of the shaft member 10 is in contact with the valve element 30, the first opening 12 of the first passage 6 is blocked, and gas from the second passage 15 does not flow into the first passage 6.

[0078] The second position is an axial position of the shaft member 10 where the valve element 30 is spaced apart from the valve seat 65 and the end face 11 is in contact with the valve element 30, so that the second passage 15 is connected to the third passage 17 but not to the first passage 6. The state in which the shaft member 10 is in the second position is realized when the shaft member 10 is located within a first predetermined axial range. The shaft member 10 receives a force toward one axial direction that increases as the magnitude of the current flowing through the first coil 71 and the second coil 72 increases. The shaft member 10 also receives a force toward the other axial direction from the first biasing members 31 and 32 that increases as the shaft member 10 moves from the first position to one axial direction. Therefore, by adjusting the magnitude of the current flowing through the first coil 71 and the second coil 72, the actual position of the shaft member 10 within the first predetermined range can be adjusted with high precision, thereby adjusting the gap between the valve element 30 and the valve seat 65. Therefore, the flow rate per unit time of the gas flowing between the second passage 15 and the third passage 17 can be adjusted with high precision.

[0079] On the other hand, suppose that a current is passed through the first coil 71 and the second coil 72, which are connected in series, from the other axial side (the second axial side) to one side (the first axial side). In this case, the shaft member 10 moves to the other axial side. Therefore, the valve element 30 moves to the other axial side due to the air pressure of the gas filling the valve element accommodating chamber 21 and the biasing force of the coil spring 67, and seats on the valve seat 65, and the shaft member 10 moves away from the valve element 30. This closes the communication port 28 and opens the first opening 12 of the first passage 6. Therefore, the second passage 15 and the shaft member accommodating chamber 22 are blocked, and the third passage 17 communicates with the fourth passage 19 via the second gas accommodating chamber 29, the first passage 6, and the first gas accommodating chamber 25.

[0080] The third position is an axial position of the shaft member 10 where the valve element 30 is seated on the valve seat 65 and the end face 11 is spaced apart from the valve element 30, thereby connecting the third passage 17 to the fourth passage 19 via the first passage 6. When the shaft member 10 is in the third position, the second passage 15 is not connected to the first passage 6 or the third passage 17. The third position is achieved when the shaft member 10 is located within a second predetermined axial range. The shaft member 10 receives a force toward the other axial direction that increases as the magnitude of the current flowing through the first coil 71 and the second coil 72 increases. The shaft member 10 also receives a force toward one axial direction from the first biasing members 31 and 32 that increases as the shaft member 10 moves from the first position to the other axial direction. For this reason, by adjusting the magnitude of the current flowing through the first coil 71 and the second coil 72, the position where the shaft member 10 actually exists within the second predetermined range can be adjusted with high precision, and as a result, the gap between the valve body 30 and the end face 11 can be adjusted. Therefore, the flow rate per unit time of the gas flowing between the third passage 17 and the first passage 6 can be adjusted with high precision.

[0081] In the above embodiment, the first coil 71 and the second coil 72, which are connected in series, are wound in opposite directions, and the direction of the current flowing through the first coil 71 and the second coil 72 is changed, thereby disposing the shaft member 10 at the second position and the third position. However, the first coil 71 and the second coil 72 do not have to be connected in series, and the current flowing through the first coil 71 and the second coil 72 may be controlled independently of each other, thereby disposing the shaft member 10 at the second position and the third position.

[0082] As described above, the proportional control valve 1 comprises an axial member 10 including a first passage 6 which is an internal passage that opens to at least one end face 11 in the axial direction, a second passage 15 connected to a gas supply source, a third passage 17 and a fourth passage 19, a valve body 30 and a valve seat 65, and an advancing / retracting drive mechanism 50 which moves the axial member 10 back and forth in the axial direction. When the second passage 15 is connected to the gas supply source, the forward / backward drive mechanism 50 can position the shaft member 10 in a first position where the valve element 30 is seated on the valve seat 65 and the end face 11 is in contact with the valve element 30, thereby disconnecting the second passage 15 from both the first passage 6 and the third passage 17 and disconnecting the third passage 17 from the first passage 6; a second position where the valve element 30 is positioned at a distance from the valve seat 65 and the end face 11 is in contact with the valve element 30, thereby connecting the second passage 15 to the third passage 17 but disconnecting the second passage 15 from the first passage 6; and a third position where the valve element 30 is seated on the valve seat 65 and the end face 11 is positioned at a distance from the valve element 30, thereby connecting the third passage 17 to the fourth passage 19 via the first passage 6.

[0083] According to the present disclosure, the shaft member 10 and the valve element 30 can be accurately positioned at desired axial positions with a simple configuration by simply appropriately varying the axial force applied to the shaft member 10 by the advance / retract drive mechanism 50 while the air pressure of the gas drawn into the second passage 15 is applying a force on the other axial side to the valve element 30. Not only can the shaft member 10 be positioned at the first to third positions, but the flow rate of gas flowing between the second passage 15 and the third passage 17 can also be adjusted with high precision, and the flow rate of gas flowing between the third passage 17 and the first passage 6 can also be adjusted with high precision. Therefore, a proportional control valve 1 can be realized that is a compact three-way valve and can also control the flow rate of gas with high precision.

[0084] The advance / retreat drive mechanism 50 may also include a first coil 71 located radially outward of the shaft member 10 and arranged to surround at least a portion of the shaft member 10, a second coil 72 located radially outward of the shaft member 10 and arranged to surround at least a portion of the shaft member 10 and spaced apart in the axial direction from the first coil 71, and a permanent magnet 73 located axially between the first coil 71 and the second coil 72 and located radially outward of the shaft member 10. The shaft member 10 may also include a large diameter portion 13 having a large outer diameter and a small diameter portion 14 having an outer diameter smaller than that of the large diameter portion 13, and the shaft member 10 may be positioned at the first position by radially opposing the large diameter portion 13 to the permanent magnet 73 with no current flowing through the first coil 71 and the second coil 72.

[0085] According to this configuration, the advance / retract drive mechanism 50 can be configured simply and compactly, and the shaft member 10 can be positioned in the axial direction with high accuracy.

[0086] In addition, one or more first biasing members 31, 32 may be further provided to bias the shaft member 10 to the first position when the first coil 71 and the second coil 72 are not energized.

[0087] According to this configuration, the shaft member 10 can be reliably positioned at the first position with no current flowing through the first coil 71 and the second coil 72. Furthermore, the position of the shaft member 10 can be adjusted with high precision by adjusting with high precision the amount of current flowing through the first coil 71 and the second coil 72. As a result, the flow rate of gas flowing between the second passage 15 and the third passage 17 can be adjusted with high precision, and the flow rate of gas flowing between the third passage 17 and the first passage 6 can also be adjusted with high precision.

[0088] In addition, one or more second biasing members 33, 34 for adjusting the radial position of the shaft member 10 may be further provided.

[0089] This configuration allows for highly accurate adjustment of the radial position of the shaft member 10. This allows for smooth axial sliding of the shaft member 10, enabling the axial position of the shaft member 10 to be positioned with even higher accuracy.

[0090] In addition, the disc portion 61 in the valve body 30 that contacts the valve seat 65 may be made of an elastic material, and the valve seat 65 may include a circular first portion 81 having approximately the same tip height, and a second portion 82 having a tip height lower than the first portion 81 and located radially outward of the first portion 81.

[0091] When the portion of the valve disc that contacts the valve seat is made of an elastic material, it is preferable that the portion that seats on the valve seat be pressed against the valve seat with sufficient force to be in close contact with the valve seat. However, if a large force is applied to the valve disc while it is seated on the valve seat, the outer periphery of the portion of the valve disc that contacts the valve seat may be excessively deformed, making the valve disc more susceptible to deterioration.

[0092] In contrast, according to the present configuration, the valve seat 65 includes the annular first portion 81 with a high tip, so that the first portion 81 can press the valve disc 30 with sufficient force, and the first portion 81 can be reliably brought into close contact with the valve disc 30 over the entire circumferential direction. Furthermore, if the outer circumferential side of the valve disc 30 is deformed by the support of the valve disc 30 by the first portion 81 to a predetermined degree or more, the outer circumferential side of the deformed valve disc is supported by the second portion 82, preventing excessive deformation of the outer circumferential side of the valve disc 30. Therefore, a special and remarkable operational effect can be obtained in which both a reliable seal when the valve disc 30 is seated on the valve seat 65 and excellent durability of the valve disc 30 can be simultaneously achieved, which are in a trade-off relationship with each other.

[0093] In addition, the second portion 82 may have a flat tip surface on the axial valve body side that extends in a direction perpendicular to the axial direction, and one or more radially extending grooves 90, 91 extending in the radial direction may be provided in the tip surface.

[0094] According to this configuration, a portion of the gas supplied from the gas supply source can be drawn into the radially extending grooves 90, 91, and a force in a direction away from the second portion 82 can be applied to the outer periphery of the valve element 30 that has been deformed by the pressure of the gas drawn into the radially extending grooves 90, 91. This further suppresses deformation of the valve element 30, further improving the durability of the valve element 30. Furthermore, since it becomes easier to adjust the force that the valve element 30 receives from the first portion 81 with high precision, it becomes easier to fine-tune the axial position of the shaft member 10 with high precision, and the shaft member 10 can be positioned in the axial direction with high precision.

[0095] Additionally, a plurality of radially extending grooves 90, 91 may be provided on the tip end surface of the second portion 82, spaced apart in the circumferential direction.

[0096] According to this configuration, it is easy to apply a force in a direction away from the second portion 82 to the outer periphery of the deformed valve body 30 uniformly in the circumferential direction, and edge wear of the valve body 30 can be suppressed.

[0097] Alternatively, a single annular groove 74 may be provided on the tip surface of the second portion 82, or multiple annular grooves spaced apart in the radial direction may be provided. The annular groove 74 may communicate with the valve element accommodating chamber 21, in which the valve element 30 is accommodated, via one or more radially extending grooves 91.

[0098] According to this configuration, a portion of the gas supplied from the gas supply source can be drawn into the annular groove 74, and the pressure of the gas drawn into the annular groove 74 can apply a force to the outer periphery of the deformed valve element 30 in a direction away from the second portion 82. Therefore, it is easy to apply a force to the outer periphery of the deformed valve element 30 in a direction away from the second portion 82 evenly in both the circumferential and radial directions, significantly improving the durability of the valve element 30. However, the proportional control valve of the present disclosure does not need to have an annular groove in the second portion.

[0099] Note that, as in the proportional control valve 1 of the above embodiment, when a biasing member (coil spring 67) that biases the valve element 30 toward the other side in the axial direction is present, the second passage 15 does not necessarily have to be connected to a gas supply source. That is, the proportional control valve 1 may include a shaft member 10 including a first passage 6 that is an internal passage that opens to at least one end face 11 in the axial direction, a second passage 15, a third passage 17, and a fourth passage 19, the valve element 30, a valve seat 65, an advance / retract drive mechanism 50 that moves the shaft member 10 forward and backward in the axial direction, and a biasing member (e.g., composed of a coil spring 67) that biases the valve element 30 toward the other side in the axial direction. The forward / backward drive mechanism 50 may position the shaft member 10 at a first position where the valve element 30 is seated on the valve seat 65 and the end face 11 is in contact with the valve element 30, so that the second passage 15 is not in communication with both the first passage 6 and the third passage 17 and the third passage 17 is not in communication with the first passage 6 either; a second position where the valve element 30 is positioned at a distance from the valve seat 65 and the end face 11 is in contact with the valve element 30, so that the second passage 15 is in communication with the third passage 17 but not in communication with the first passage 6; and a third position where the valve element 30 is seated on the valve seat 65 and the end face 11 is positioned at a distance from the valve element 30, so that the third passage 17 is in communication with the fourth passage 19 via the first passage 6.

[0100] According to this configuration, since a biasing member that biases the valve element 30 to the other side in the axial direction is provided, when the shaft member 10 moves to the other side in the axial direction and is axially separated from the valve element 30, the biasing member can seat the valve element 30 on the valve seat 65. Therefore, also with this configuration, the gas flow rate can be controlled with high precision, and a compact three-way valve with a simple structure can be realized.

[0101] The present disclosure is not limited to the above-described embodiments and their modifications, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents.

[0102] For example, in the above embodiment, the valve seat 65 has the second portion 82 radially outward of the annular first portion 81. However, as shown in Figure 9, that is, an enlarged cross-sectional view of a modified proportional control valve 101 corresponding to Figure 7, the valve seat 165 of the case 105 may have the first portion 81 but may not have the second portion 82.

[0103] 10 , that is, a cross-sectional view of a proportional control valve 201 according to another modified example corresponding to FIG. 5 , the advance / retract drive mechanism 250 may include a first coil 271 located radially outward from the shaft member 210 and arranged to surround at least a portion of the shaft member 210, and a second coil 272 located radially outward from the shaft member 210 and arranged to surround at least a portion of the shaft member 210, and arranged axially spaced from the first coil 271. The advance / retract drive mechanism 250 may also include a permanent magnet 273 fixed to the outer circumferential surface of the shaft member 210. Then, in a state in which the first coil 271 and the second coil 272 are not energized, the shaft member 210 may be located at a first position where the valve element 30 is seated on the valve seat 265 and an end face 211 on one axial side of the shaft member 210 contacts the valve element 30 based on a magnetic field generated by the permanent magnet 273.

[0104] In this configuration, the shaft member 210 can be selectively positioned at the first position, the second position, or the third position by passing appropriate currents through the first coil 271 and the second coil 272, respectively. Furthermore, the advance / retract drive mechanism 250 can be configured simply and compactly, and the shaft member 210 can be positioned in the axial direction with high accuracy. In the advance / retract drive mechanism whose basic configuration is shown in FIG. 10 , the shaft member 210 is biased to the first position by a magnetic spring. However, the advance / retract drive mechanism whose basic configuration is shown in FIG. 10 may also include one or more first biasing members that bias the shaft member 210 to the first position when no current is flowing through the first coil and the second coil. Furthermore, the advance / retract drive mechanism whose basic configuration is shown in FIG. 10 may also include a second biasing member that centers the shaft member 210 and positions it radially. 10, the first coil 271 and the second coil 272 may be connected in series and wound in opposite directions. Also, in the proportional control valve 201, the basic configuration of which is shown in FIG. 10, the valve seat may have the second portion described above in addition to the first portion.

[0105] The advancing / retracting drive mechanism may be any mechanism capable of advancing and retracting the shaft member in the axial direction. For example, the advancing / retracting drive mechanism may have only one coil. Alternatively, the advancing / retracting drive mechanism may have one or more coils but no permanent magnet. Alternatively, the advancing / retracting drive mechanism may be a fluid pressure applying mechanism that applies axial fluid pressure, such as hydraulic pressure or air pressure, to the shaft member to advance and retract the shaft member in the axial direction. Furthermore, the first passage may have only a portion extending in the axial direction, and the first opening of the first passage may be present on one end face of the shaft member, while the second opening of the first passage may be present on the other end face of the shaft member. [Explanation of symbols]

[0106] 1 proportional control valve, 1a first inlet, 1b second inlet, 1c third inlet, 302 gas supply source, 303 first guide passage, 304 second guide passage, 305 third guide passage, 306 first branch section, 307 on / off valve, 309 air spring, 309a internal chamber, 310 control system, 311 fourth guide passage, 312 second branch section, 313 two-way shutoff valve, 315 control device, 315a control section, 315b memory section, 317 filter, 317a first filter, 317b second filter, 318 silencer, 319 height detection sensor, 321 vehicle body, P1 initial air pressure, P2 control switching air pressure, P3 target air pressure.

Claims

1. a first guide passage for guiding gas from a gas supply source; a first branching portion that branches the first guide passage into a second guide passage and a third guide passage; an on-off valve disposed in the second guide passage; a proportional control valve disposed in the third guide passage and capable of controlling the flow rate per unit time of gas that is smaller than the flow rate per unit time of gas that can pass through the on-off valve by controlling the opening degree; a fourth guide passage for guiding gas to the internal chamber of the member; a second branch portion that branches the fourth guide passage to a side of the second guide passage opposite to the first branch portion side of the on / off valve and to a side of the third guide passage opposite to the first branch portion side of the proportional control valve; a control device that controls the air pressure in the internal chamber to a target air pressure by controlling the opening degree of the proportional control valve while controlling the on-off valve to be open at a first timing and controlling the on-off valve to be closed at a second timing after the first timing; An internal pressure control system comprising:

2. 2. The internal pressure control system according to claim 1, wherein a two-way shutoff valve is disposed between the member and the second branch portion in the fourth guide passage, or a two-way shutoff valve is disposed between the on / off valve and the second branch portion in the second guide passage.

3. The internal pressure control system according to claim 1 or 2, wherein the opening of the proportional control valve is greater than 0 at the first timing.

4. 4. The internal pressure control system according to claim 3, wherein the control device switches from the first timing to the second timing when it determines that the air pressure in the internal chamber has reached a predetermined percentage of the target air pressure.

5. the member is an air spring, The internal pressure control system according to claim 3 , wherein the switching from the first timing to the second timing is performed based on a physical quantity related to the height of the air spring.

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