FLOW RATE REGULATING VALVE

To provide a flow rate regulating valve that is capable of highly accurate control when a flow rate is small, and supplying gaseous fuel at a large flow rate. A flow rate regulating valve 30 according to the present invention includes: a main body 2 having a small-diameter flow path 3A, a tapered flow path 3AT continuous with the small-diameter flow path 3A, and a large-diameter flow path 3B continuous with the tapered flow path 3AT; a shaft 1 having a small-diameter tip 1A that can be inserted into the small-diameter flow path 3A from the large-diameter flow path 3B side of the main body 2, and a tapered portion 1AT continuous with the small-diameter tip 1A; an opening adjustment rotating member 4; and a conversion mechanism 5 that converts rotation of the opening adjustment rotating member 4 into movement in an axial direction of the shaft 1, wherein when the small-diameter tip 1A of the shaft 1 is inserted into the small-diameter flow path 3A of the main body 2, a gap δ is formed between an outer circumferential surface of the small-diameter tip 1A and an inner circumferential surface of the small-diameter flow path 3A, and an outer circumferential surface of the tapered portion 1AT of the shaft 1 is configured to be engageable with an inner circumferential surface of the tapered flow path 3AT of the main body 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2023-061124 filed on Apr. 5, 2023, the disclosure of which is incorporated herein by reference.

Not Applicable

BACKGROUND

1. Field of the Invention

The present invention relates to a flow rate regulating valve suitably used in a filling device for filling hydrogen gas into a tank of a fuel cell vehicle (FCV) and others.

2. Description of the Related Art

As one measure to address environmental problems in recent years, FCVs that use hydrogen gas as fuel and equipment related thereto have been actively developed. In order to promote the spread of the FCVs, a device that can stably fill hydrogen gas into an FCV is required. The applicant has already proposed such a hydrogen filling device, for example in JP-A-2021-139390, and in the gazette is disclosed a flow rate regulating valve that is installed in a hydrogen supply pipe and controls the flow rate of hydrogen gas based on a signal from a control device.

In addition, another flow rate regulating valve which is proposed in JP-A-2021-196001 includes a flow path formed in a main body to communicate an inflow port and an outflow port, a valve seat formed in the flow path, a valve body that contacts with and separates from the valve seat to open and close the flow path, and an actuator for moving the valve body. In this flow rate regulating valve, a rotating shaft of a stepping motor in the actuator is connected to a ball screw, and the ball screw is disposed in a slider that is movable up and down in a cylindrical upper cover, and a rotational motion of the motor is converted into a linear motion of the slider. With this configuration, opening/closing control can be performed reliably even when a working fluid is at high pressure.

In the above-mentioned flow rate regulating valve, however, the cross-sectional area of the flow path suddenly increases and the flow rate increases the moment the valve body separates from the valve seat, it is therefore difficult to control the valve opening or flow rate especially when a small flow rate of hydrogen is required. Here, it is possible to control the flow rate with high precision by restricting the flow rate, but when filling with gaseous fuel such as hydrogen, there is a desire to finish the filling as quickly as possible, which necessitates to fill with a large flow rate. No flow rate regulating valve has yet been proposed that can perform highly accurate control even at a small flow rate and can meet the demand for gaseous fuel supply at a large flow rate.

The contents of JP-A-2021-139390 gazette and JP-A-2021-196001 are incorporated herein by reference in their entirety.

BRIEF SUMMARY

The present invention has been proposed in view of the problems of the prior art described above, and an object thereof is to provide a flow rate regulating valve that is capable of highly accurate control even when the flow rate is small, and supplying gaseous fuel, etc., at a large flow rate.

A flow rate regulating valve30according to the present invention is characterized by including: a main body2having a small-diameter flow path3A, a tapered flow path3AT continuous with the small-diameter flow path3A, and a large-diameter flow path3B continuous with the tapered flow path3AT; a shaft1having a small-diameter tip1A that can be inserted into the small-diameter flow path3A from the large-diameter flow path3B side of the main body2, and a tapered portion1AT continuous with the small-diameter tip1A; an opening adjustment rotating member4; and a conversion mechanism5that converts rotation of the opening adjustment rotating member4into movement in an axial direction of the shaft1, wherein when the small-diameter tip1A of the shaft1is inserted into the small-diameter flow path3A of the main body2, a gap δ is formed between an outer circumferential surface of the small-diameter tip1A and an inner circumferential surface of the small-diameter flow path3A, and an outer circumferential surface of the tapered portion1AT of the shaft1is configured to be engageable with an inner circumferential surface of the tapered flow path3AT of the main body2.

In the flow rate regulating valve30, the conversion mechanism5preferably includes a threaded portion5A between a female thread4C formed on the opening adjustment rotation member4and a male thread1C formed on the shaft1.

It is preferable that the flow rate regulating valve30further includes a co-rotation prevention mechanism6(a co-rotation prevention member6A and a co-rotation prevention bolt6B) that prevents the shaft1from co-rotating with the opening adjustment rotating member4when the opening adjustment rotating member4is rotated.

It is preferable that the flow rate regulating valve30further includes a rapid opening adjustment member (a rapid opening adjustment button)7that moves the shaft1toward the small-diameter tip1A.

According to the flow rate regulating valve30of the present invention with the above construction, the tapered portion1AT adjacent to the small-diameter tip1A constitutes a valve body, and the tapered flow path3AT adjacent to the small-diameter flow path3A formed in the main body2constitutes a valve seat, and the valve30is closed when the outer circumferential surface of the tapered portion1AT engaging with the inner circumferential surface of the tapered flow path3AT, and the valve30opens when the outer circumferential surface of the tapered portion1AT separates from the inner circumferential surface of the inner circumferential surface of the tapered flow path3AT.

Here, the gap δ exists between the outer circumferential surface of the small-diameter tip1A and the inner circumferential surface of the small-diameter flow path3A. When the small-diameter tip1A is inserted into the small-diameter flow path3A with the flow rate adjustment valve30open, a gaseous fuel flows through the gap δ. The gap δ is minute, and if the distance that the gaseous fuel flows through the gap δ, that is, a shaft axial length Lt, is long, the flow path resistance will be large and the gaseous fuel flow rate will be small, but if the distance is short, the flow path resistance will be small and the flow rate of the gaseous fuel will increase.

According to the present invention, the flow rate of the gaseous fuel flowing through the gap δ can be precisely fine-tuned by adjusting the length of the gaseous fuel flowing through the gap δ, that is, the length in which the small-diameter tip1A is inserted into the small-diameter flow path3A.

Furthermore, since the conversion mechanism5that converts the rotation of the opening adjustment rotating member4into axial movement of the shaft1is provided, the shaft1can be moved in the axial direction by rotating the opening adjustment rotation member4, which allows the length Lt of the small-diameter tip1A inserted into the small-diameter flow path3A, that is, the distance through which the gaseous fuel flows through the gap δ to be adjusted. Since this mechanism constitutes a mechanism that converts the rotation of a screw into movement in the axial direction of the screw, even if the amount of rotation of the opening adjustment rotating member4is large, the amount of movement of the shaft1in its axial direction does not become large, so that the amount of movement of the shaft1can be finely adjusted.

When flowing through the gap δ, the gaseous fuel has a small flow rate because the flow path resistance of the gap δ is large, and fine adjustment in the small flow rate region can be easily and reliably performed. Further, even if the tapered portion1AT is separated from the tapered flow path3AT, the gaseous fuel flows through the gap δ where the resistance of the tapered flow path3AT is large. Therefore, according to the flow rate regulating valve30of the present invention, a large amount of gaseous fuel is prevented from flowing at the moment of opening.

Here, from the state where the flow rate regulating valve30of the present invention is closed, through the state where a small flow rate of hydrogen flows through the gap δ, to the state where the hydrogen flow rate rapidly increases, flow rate adjustment is performed by the movement of the small-diameter tip1A in a direction away from the small-diameter flow path3A. That is, according to the present invention, the transition from the closed state to the small flow rate state to the large flow rate state is continuously performed by an operation of moving the small-diameter tip1A in a direction to remove it from the small-diameter flow path3A. As a result, according to the flow rate adjustment valve30, hydrogen flows at a small flow rate when the valve is opened, the flow rate gradually increases, and after a certain state (the state shown inFIG.9), the flow rate increases rapidly.

When the differential pressure between the container to be filled with gaseous fuel (25: for example, a hydrogen tank of an FCV) and a gaseous fuel supply tank21decreases at filling, it is necessary to switch the gaseous fuel supply tank to an ultra-high-pressure tank22. When switching to the ultra-high-pressure tank22, the opening degree of the flow rate regulating valve30should be decreased to reduce the flow rate of gaseous fuel.

In the present invention, if the rapid opening adjustment member (opening rapid adjustment button)7is provided, pressing the rapid opening adjustment member7toward a flow path adjustment section10in the shaft axial direction (a region LC inFIG.4) enables the entire shaft1to move toward the flow path adjustment section10in the axial direction of the shaft together with the opening adjustment dial4screwed together at a base1B. As a result, the length of the small-diameter tip1A inserted into the small-diameter flow path3A increases, and the flow path resistance increases, which decreases the flow rate from the flow rate regulating valve30(a region LD inFIG.4). That is, according to the present invention, pressing the opening degree rapid adjustment member7toward the flow path adjustment section10side in the shaft axial direction allows the flow rate from the flow rate adjustment valve30to be sharply reduced, and the gaseous fuel supply tank can be replaced safely and smoothly.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the illustrated embodiment, an example will be described in which an FCV is filled with hydrogen as gaseous fuel using a hydrogen filling device as a filling device. First, with reference toFIGS.1to3, functions of the flow rate regulating valve30during hydrogen filling will be described.

InFIG.1, a hydrogen gas supply tank20side is comprised of a high-pressure tank21and an ultra-high-pressure tank22. The hydrogen gas supply tank20(21,22) is connected to a fuel tank25of a fuel cell vehicle FCV via a hydrogen pipe26, and a flow rate regulating valve30is interposed in the hydrogen pipe26.

In the hydrogen pipe26, a hydrogen pipe26A connected to the high-pressure tank21and a hydrogen pipe26B connected to the ultra-high-pressure tank22merge at a merging point27. Switching on/off valves23A,23B are installed in the hydrogen pipes26A,26B, respectively.

When filling with hydrogen gas, the fuel tank25and the high-pressure tank21are initially communicated with each other, and when the pressure difference between the fuel tank25and the high-pressure tank21decreases, the high-pressure tank21is switched to the ultra-high-pressure tank22. When switching the high-pressure tank21to the ultra-high-pressure tank22, operate the switching valves23A and23B, and at the beginning of switching, reduce the opening degree of the flow rate adjustment valve30to reduce the flow rate of hydrogen gas in the flow rate adjustment valve30. InFIG.1, illustration of the hydrogen filling device is omitted.

In the hydrogen filling described with reference toFIG.1, the characteristic of the pressure of the fuel tank25versus time is shown as a characteristic line L2inFIG.2. When the slope θ in the characteristic line L2is large, a rapid pressure change (increase) has occurred, and the filling speed becomes faster, but the possibility of damage to the fuel tank25and the hydrogen pipe26shown inFIG.1increases.

On the other hand, when filling with hydrogen gas, there is a demand to perform hydrogen filling at high speed in order to finish filling as early as possible, and as far as related equipment allows in terms of pressure resistance, durability, etc. To meet this request, it is necessary to control the hydrogen flow rate (for example, mass flow rate) with high precision, and the flow rate adjustment valve30(FIG.1) is provided to perform this control.

An area LA in the characteristic line L2shown inFIG.2indicates an area where the hydrogen gas supply side described above is switched from the high-pressure tank21to the ultra-high-pressure tank22.

InFIG.3, the characteristics of the opening degree of the flow rate adjustment valve and the hydrogen flow rate are shown by a characteristic line L3, and after the opening degree of the flow rate adjustment valve is opened from the closed state (the origin inFIG.3), the opening degree gradually increases (a region near the origin inFIG.3). Then, a small flow rate region R1in which the opening degree is small shifts to a large flow rate region R2in which the opening degree increases.

InFIG.3, a slope θ2of a characteristic line L32in the large flow rate region R2is larger than a slope θ1of a characteristic line L31in the small flow rate region R1. Reducing the slope θ1of the characteristic line L31allows pressure increase in the small flow rate region R1to be reduced, thereby damage to the fuel tank25of the FCV and various pipes can be reduced. Further, if the slope θ2of the characteristic line L32is large, the hydrogen flow rate becomes large, which meets the demand for high-speed hydrogen filling.

Here, the hydrogen supply system (including related equipment such as the fuel tank25of the FCV) is likely to be damaged in the small flow rate region R1, especially immediately after the flow rate adjustment valve30is opened.

Regarding the flow rate adjustment valve30shown inFIGS.5to13according to the illustrated embodiment, the operation of the flow rate adjustment valve in the small flow rate region R1will be explained with reference toFIGS.5to9, and the operation thereof in the large flow rate region R2will be explained with reference toFIGS.10and11.

InFIG.3, a reference numeral L33is the boundary between the small flow rate region R1and the large flow rate region R2, and in the illustrated embodiment, the state indicated by the reference numeral L33inFIG.3will be described later with reference toFIG.9.

InFIG.4, in a characteristic line L4illustrating time characteristic of opening of the flow rate adjustment valve30during hydrogen filling, the opening linearly increases with the slope θ1from immediately after the start of filling until a time LB. As described above, immediately after the start of filling, hydrogen gas is supplied at a small flow rate (the small flow rate region R1), and then hydrogen gas is supplied at a large flow rate (the large flow rate region R2). Here, there is a possibility that the slope in the large flow rate region R2changes from the slope θ1in the small flow rate region R1and becomes larger, but for the sake of simplification, in the characteristic line L4inFIG.4, the small flow rate region R1and the large flow rate region R2are expressed by a straight line with the same slope θ1.

InFIG.4, regions indicated by symbols LC and LD indicate timing of switching from the high-pressure tank21to the ultra-high-pressure tank22. In the region indicated by the symbol LC, the valve opening degree is rapidly decreased in order to switch the tank. Then, after passing through the region LD for tank switching, the fuel tank25of the FCV is filled with hydrogen from the ultra-high-pressure tank22, and the opening degree of the flow rate regulating valve30increases linearly according to the characteristic line L41. The characteristics shown inFIGS.3and4are realized by the flow rate regulating valve30according to the illustrated embodiment.

The first embodiment of the present invention will be described with reference toFIGS.5to11. InFIG.5, the flow rate adjustment valve according to the first embodiment is indicated by the reference numeral30as a whole, and the valve30includes a shaft1having a small-diameter tip1A, a main body2in which a small-diameter flow path3A is formed, an opening adjustment rotating member (an opening adjustment dial)4and a conversion mechanism5that converts rotation of the opening adjustment rotating member4into movement in an axial direction of the shaft1.

The shaft1has the small-diameter tip1A located in the flow path adjustment section10(the area indicated by the two-dot chain line inFIG.5) on the tip side (upper side inFIG.5), and a base1B located near the other end (lower end inFIG.5) of the small-diameter tip1A, and is movable in the axial direction (in the vertical direction inFIG.5) within the space formed in the main body2. A flow path forming portion, which constitutes a part of the main body2and is a region in which the flow path3A into which the small-diameter tip1A is inserted, is formed is indicated by a reference numeral2C inFIG.5.

The opening adjustment dial4is a hollow member, and is configured by connecting a shaft fitting portion4A and a dial operating portion4B, which are cylindrical members having different diameters in the direction of the shaft center axis. The opening adjustment dial4is arranged at an end of the flow rate adjustment valve30on the opposite side to the flow path adjustment section10(lower side inFIG.5).

A female thread4C is formed on an inner circumferential surface of the shaft fitting portion4A of the opening adjustment dial4, and is threadedly engaged with a male thread1C formed on the base portion1B to form a threaded portion5A. The threaded portion5A constitutes a conversion mechanism5that converts rotation of the opening adjustment dial4into axial movement of the shaft1. The conversion mechanism5is a mechanism that has a function of converting rotational motion (rotation of a screw) into linear motion (movement of a screw in the axial direction), and in the illustrated embodiment is configured by a screw mechanism.

The dial operating portion4B of the opening adjustment dial4is arranged to protrude from the main body2(downward inFIG.5). When the dial operation section4B is rotated, the rotation of the dial operation section4B is converted into a movement of the shaft1in the shaft axial direction (up and down direction inFIG.5) at the screwing section5A. As a result, the shaft1moves up and down. In order to smoothly rotate the opening adjustment dial4, the lower end of the shaft fitting portion4A of the opening adjustment dial4is supported by a thrust bearing8inside the main body2of the flow rate adjustment valve30. Therefore, even if the opening adjustment dial4is pressed in the shaft axial direction, it can rotate smoothly. The opening adjustment dial4is operated manually, but it can also be rotated by means such as a motor.

A hydrogen gas supplied from the high-pressure tank21(or ultra-high-pressure tank22: seeFIG.1) flows into the main body2from the hydrogen inlet2A (arrow A1), flows through the flow path adjustment section10, and flows through the outlet2B (arrow A2). Then, hydrogen gas is filled into the fuel tank25(FIG.1) of an FCV via a filling nozzle (not shown) of the hydrogen filling device. In the flow path adjustment section10, the valve opening degree (or hydrogen gas flow rate) of the flow rate adjustment valve30is finely adjusted from the start of hydrogen gas filling by the axial position of the shaft1(small-diameter tip1A), and the pressure and flow rate are controlled.

In the flow path adjustment section10, when the shaft1moves upward, the small-diameter tip1A is inserted into the small-diameter flow path3A (seeFIG.6) formed in the main body2, and an axial length of the small-diameter tip1A inserted into the small-diameter flow path3A becomes longer. On the other hand, in the flow path adjustment section10, when the shaft1moves downward, an axial length of the small-diameter tip1A inserted into the small-diameter flow path3A (seeFIG.6) becomes smaller, and furthermore, the small-diameter tip1A get off the small-diameter flow path3A.

As will be described later with reference toFIG.6, if the length in the axial direction of the small-diameter tip1A inserted into the small-diameter flow path3A is large, flow resistance in the small-diameter flow path3A increases, and flow rate of the hydrogen gas flowing through the small-diameter flow path3A becomes smaller. On the other hand, when the length in the axial direction of the small-diameter tip1A inserted into the small-diameter flow path3A is small, flow resistance in the small-diameter flow path3A becomes small, and flow rate of hydrogen gas flowing through the small-diameter flow path3A becomes large. The flow rate adjustment control of hydrogen gas in the flow path adjustment section10will be described in detail with reference toFIG.6as well.

InFIG.5, when the opening adjustment dial4is rotated, if the shaft1rotates together with the opening adjustment dial4, the shaft1will not move in the axial direction (vertical direction inFIG.5). In order to prevent the shaft1from rotating together with the opening adjustment dial4when the opening adjustment dial4is rotated, the co-rotation prevention mechanism6is provided in the flow rate adjustment valve30. The co-rotation prevention mechanism6includes a co-rotation prevention member6A and co-rotation prevention bolts6B. Here, it is also possible to use pins instead of the co-rotation prevention bolts6B.

The co-rotation prevention member6A has a rotating body shape that is a combination of a hollow cylindrical upper member6A1and a lower member6A2. A collar portion6A3extending radially outward is formed at an upper end of the upper member6A1, and a groove6A4(groove of the co-rotation prevention member) extending in the shaft axial direction is formed in the lower member6A2. Since the co-rotation prevention member6A is attached to the main body2by means not shown, it does not rotate in the circumferential direction of the shaft1.

The co-rotation prevention bolts6B are screwed into the large diameter portion1D of the shaft1from the groove6A4of the lower member6A2, and a nut6D is fitted to the other end of the bolt6B. Since the groove6A4extends in the shaft axial direction, the co-rotation prevention bolts6B and the shaft1are movable in the shaft axial direction (vertical direction inFIG.5).

Inside the main body2, a plurality of (for example, four) biasing springs6C are provided radially outward of the co-rotation prevention member6A at equal intervals in the circumferential direction of the shaft1. The upper end of the biasing spring6C (inFIG.5) is in contact with the flange portion6A3fixed in the shaft axial direction, and the lower end of the biasing spring6C is in contact with the co-rotation prevention bolt6B. The elastic repulsive force of the biasing spring6C that tends to expand in the shaft axial direction always acts to press the co-rotation prevention bolt6B downward in the shaft axial direction (inFIG.5).

A shaft rotation prevention bearing6E is provided on the co-rotation prevention bolt6B so as to come into contact with the groove6A4of the lower member6A2. Since the shaft rotation prevention bearing6E rotates smoothly in the circumferential direction of the co-rotation prevention bolt6B, which assists the co-rotation prevention bolt6B to smoothly rotate in the shaft axial direction (vertical direction inFIG.5) within the groove6A4of the co-rotation prevention member6A. Therefore, a rotation of the opening adjustment dial4is converted into an axial movement of the shaft1in the threaded portion5A (conversion mechanism5), and the shaft1is smoothly moved in the shaft axial direction (vertical direction inFIG.5).

InFIG.5, a movable seal9is arranged in the axial direction of the shaft1at an intermediate position between the small-diameter tip1A and the co-rotation prevention member6A. The movable seal9prevents hydrogen gas (arrow A1) that has flowed into the main body2from the inlet2A from leaking along the boundary between the shaft1and the main body2in a direction opposite to the outlet2B (downward inFIG.5). In addition to the leakage prevention function, the movable seal9also has a function of supporting smooth relative movement of the shaft1and the main body2in the shaft axial direction. The movable seal9prevents radial movement of the shaft1.

Further, an axial bearing11is arranged on the inner circumferential surface of the co-rotation prevention member6A. With the axial bearing11, smooth axial movement of the shaft1(vertical direction inFIG.5: relative movement in the vertical direction with respect to the main body2) is facilitated.

InFIG.5, a rapid opening adjustment member (rapid opening adjustment button)7having a function of quickly moving the shaft1to the small-diameter tip1A side (to the flow path adjusting section10side, upward inFIG.5) is disposed to the end of the flow rate regulating valve30on the side opposite to the small-diameter tip1A (the side opposite to the flow path adjusting section10: lower inFIG.5). The rapid opening adjustment button7includes a button operation part7A and a shaft part7B, and is fastened to a female screw formed in the base part1B at a shaft threaded part7C near a tip of the shaft part7B, and the shaft part7B is fixed to the base part1B. Pressing the opening rapid adjustment button7toward the small-diameter tip1A (upward inFIG.5) allows the entire shaft1to move toward the small-diameter flow path3A (upward inFIG.5).

In addition toFIG.5, with reference toFIG.6, control of the opening degree of the flow rate regulating valve30or the hydrogen gas flow rate in the flow path adjusting section10will be described. In the state shown inFIGS.5and6, the flow rate regulating valve30is closed.

InFIG.6showing details of the flow path adjusting section10, a flow path (hydrogen gas flow path)3is formed in the flow path forming section2C that constitutes the region into which the small-diameter tip1A is inserted, and the flow path forming section2C constitutes a part of the main body2. The flow path3is formed of a small-diameter flow path3A communicating with the outlet2B, a large-diameter flow path3B communicating with the flow path inlet2A, and a tapered flow path3AT connecting them.

A tapered portion1AT is formed on the inlet2A side (lower side inFIGS.5and6) of the small-diameter tip1A, and the inlet2A side of the tapered portion1AT is continuous with the shaft (shaft main body)1.

In the state shown inFIG.6, the small-diameter tip1A is inserted into the small-diameter flow path3A, and the outer circumferential surface of the tapered portion1AT is engaged (seated) with the inner circumferential surface of the tapered flow path3AT. Here, the tapered portion1AT constitutes a valve body, and the tapered flow path3AT constitutes a valve seat. In the state shown inFIG.6, the flow rate regulating valve30is closed and hydrogen gas cannot pass through. In order for the tapered portion1AT constituting the valve body to engage (seat) the tapered flow path3AT from a state where it is not engaged with the tapered flow path3AT, the tapered portion1AT is required to move upward inFIGS.5and6(to the outlet2B side).

InFIG.6, an annular gap δ with extremely small radial dimension exists between the outer circumferential surface of the small-diameter tip1A and the inner circumferential surface of the small-diameter flow path3A. The dimension of the gap δ in the shaft radial direction is extremely small, for example, 3% or less of the diameter of the small-diameter tip1A. When the tapered portion1AT forming the valve body and the tapered flow path3AT are separated from each other, a hydrogen gas flows through the annular gap δ at a small flow rate, as will be described later with reference toFIG.8. Further, the axial length Lt of the shaft in which the small-diameter tip1A is inserted into the small-diameter flow path3A is the distance (shaft axial length) through which hydrogen gas flows through the annular gap δ.

When the flow rate adjustment valve30shown inFIGS.5and6is closed, the opening adjustment dial4is rotated to move the shaft1(small-diameter tip1A) (downward inFIG.5), which state is shown inFIGS.7and8.

InFIG.7, the position of the threaded part5A where the male thread1C on the outer periphery of the base1B and the female thread4C of the shaft fitting part4A of the opening adjustment dial4are threaded becomes the base1B side compared toFIG.5(lower side inFIGS.5and7). Since the position of the opening adjustment dial4in the shaft center axis direction (vertical position inFIGS.5and7) is fixed, when the threaded part5A becomes the base1B side as shown inFIG.7, the shaft1(small-diameter tip1A) is located lower relative to the main body2compared toFIG.5.

InFIG.8, which shows details of the flow path adjustment section10inFIG.7, since the shaft1(small-diameter tip1A) has descended, the tapered portion1AT is separated from the tapered flow path3AT, and the flow rate adjustment valve30opens. Here, the axial length Lt of the shaft in which the small-diameter tip1A is inserted into the small-diameter flow path3A is shorter than that inFIG.6.

In the state shown inFIG.8, a hydrogen gas flows within the annular gap δ. The radial dimension of the gap δ is minute, and in the state ofFIG.8, the axial length Lt of the shaft1inserted into the small-diameter flow path3A is long, so that the flow path resistance in the annular gap δ is large, and the flow rate of hydrogen gas flowing within the gap δ is small.

Here, when the shaft1(small-diameter tip1A) is lowered compared toFIG.8and the axial length Lt of the shaft1inserted into the small-diameter flow path3A becomes shorter (not shown), the flow path resistance at the gap δ becomes smaller, and the hydrogen gas flow rate increases. In the illustrated first embodiment, the flow rate of a hydrogen gas flowing through the annular gap δ can be finely adjusted by rotating the opening adjustment dial4and varying the shaft axial length Lt to vary the flow path resistance.

From the state shown inFIGS.7and8, when the opening adjustment dial4is rotated to further move the shaft1(small-diameter tip1A) toward the opening rapid adjustment button7(the shaft1is further lowered inFIGS.7and8), as shown inFIG.9, an end surface1AB of the small-diameter tip1A comes to a position where it aligns with a boundary3C between the small-diameter flow path3A and the tapered flow path3AT. In other words, the shaft axial length Lt (FIG.8) is zero.

FIG.9shows a state of the boundary between the small flow rate area and the large flow rate area of the flow rate regulating valve30according to the illustrated first embodiment. The small flow rate area R1inFIGS.3and4is the state shown inFIGS.5to8, and the large flow rate area R2inFIGS.3and4is the state shown inFIGS.10and11. The state of the boundary between the small flow rate area R1and the large flow rate area R2is the state shown inFIG.9. As explained with reference toFIGS.5to9, in the small flow rate region, moving the shaft1(small-diameter tip1A) in the shaft axial direction varies the flow path resistance in the gap δ to control the hydrogen flow rate.

When the shaft1moves in the shaft axial direction, the rotation of the opening adjustment dial4is converted into movement in the axial direction by the threaded portion5A. Therefore, the amount of movement of the shaft1(small-diameter tip1A) in the shaft axial direction is small relative to the amount of rotation of the opening adjustment dial4, allowing fine adjustment. That is, the flow rate in the small flow rate region can be finely adjusted. Here, the flow rate of hydrogen gas flowing through the gap δ is small.

Even immediately after the tapered portion1AT is separated from the tapered flow path3AT from the closed state of the flow rate adjustment valve30shown inFIGS.5and6, the region Lt of the minute gap δ is long and the flow path resistance is large, so that a large amount of hydrogen gas cannot flow through δ. That is, the flow rate is reliably prevented from increasing rapidly immediately after the flow rate regulating valve30is opened from the closed state.

FIGS.10and11show a state in which the characteristics of the large flow rate region R2inFIG.4is realized by further lowering the shaft1(small-diameter tip1A) from the state shown inFIGS.7and8by rotating the opening adjustment dial4of the flow rate adjustment valve30.

InFIG.10, the end surface of the dial operation section4B on the shaft1side (the upper side inFIG.10) is indicated by the symbol4BT, and the end surface of the base1B on the dial operation section4B side (the lower side inFIG.10) is indicated by the symbol1BB. The distance between the shaft1side end surface4BT of the dial operation section4B and the dial operation section4B side end surface1BB of the base1B (distance in the axial direction of the shaft1) is indicated by the symbol L10.

InFIG.11showing the flow path adjustment section10inFIG.10, the end surface1AB of the small-diameter tip1A is located below the boundary3C between the small-diameter flow path3A and the tapered flow path3AT. The cross-sectional area of the hydrogen gas flow path is constituted by the annular gap δ between the outer circumferential surface of the small-diameter tip1A and the inner circumferential surface of the small-diameter flow path3A in the small flow rate region ofFIGS.5to8. However, in the state ofFIG.11(large flow rate region), it is formed in the region between the outer circumferential surface of the small-diameter tip1A and the inner circumferential surface of the tapered flow path3AT. When the shaft1(small-diameter tip1A) is further lowered, a hydrogen gas flow path is formed in a region between the outer circumferential surface of the small-diameter tip1A and the inner circumferential surface of the large-diameter flow path3B. As a result, the cross-sectional area of the hydrogen gas flow path in the states shown inFIGS.10and11increases dramatically, a hydrogen gas flows at a large flow rate, and the demand for shortening the filling time can be met.

According to the illustrated embodiment, the transition from the closed state to the small flow rate state to the large flow rate state is all performed continuously by an operation of moving the small-diameter tip1A in a direction away from the small-diameter flow path3A. Therefore, according to the flow rate regulating valve30of the illustrated embodiment, through continuous and smooth operation, a hydrogen gas flows at a small flow rate immediately after closing, that is, when the valve is opened, and the small flow rate gradually increases (low flow area R1), and after the state shown inFIG.9(L33inFIG.3), the hydrogen gas flow rate increases rapidly (large flow rate region R2).

In order to switch from the high-pressure tank21to the ultra-high-pressure tank22(regions LC and LD inFIG.4) when the flow rate adjustment valve30is in the large flow area shown inFIG.10, it is necessary to rapidly reduce the opening degree of the valve30to reduce the flow rate of hydrogen gas.

In the illustrated first embodiment, inFIG.10, the opening rapid adjustment button7is pressed toward the flow path adjustment section10side (small-diameter tip1A side: upward inFIG.10) in the shaft axial direction (in the area LC shown inFIG.4), the entire shaft1together with the opening adjustment dial4can be quickly moved toward the flow path adjustment section10in the shaft axial direction.

Since the dial operation part4B of the opening adjustment dial4has a small-diameter cylindrical shape and passes through the opening2D, when the opening rapid adjustment button7is pressed toward the small-diameter tip1A side in the shaft axial direction (upward inFIG.10), the dial operating section4B moves in the shaft axial direction together with the shaft1without interfering with the main body.

FIG.12shows a state in which the entire shaft1is moved toward the flow path adjustment section10in the shaft axial direction (upward inFIG.12) by operating the opening rapid adjustment button7(button operating section7A). In comparison toFIGS.5,7, and10, inFIG.12, the opening adjustment dial4(shaft fitting part4A, dial operation part4B) moves together with the shaft1toward the flow path adjustment section10in the shaft axial direction.

A clearance (distance in the axial direction of the shaft1) between the end surface4BT on the shaft1side (upper side inFIG.10) of the dial operation section4B and the end surface1BB on the dial operation section4B side (lower side inFIG.10) of the base1B is shown by the symbol L12inFIG.12. The opening adjustment dial4(shaft fitting part4A, dial operation part4B) is moved toward the flow path adjustment section10side in the shaft axial direction by the difference between the interval L10inFIG.10and the interval L12inFIG.12. The length Lt (seeFIGS.6and8) in which the small-diameter tip1A is inserted into the small-diameter flow path3A is long, the flow path resistance increases, and the flow rate of a hydrogen gas flowing through the flow rate adjustment valve30becomes small (the area LD inFIG.4). Therefore, by quickly moving the entire shaft1toward the flow path adjustment section10in the axial direction of the shaft1, the gaseous fuel supply tank can be replaced safely and smoothly.

Next, referring toFIG.13, the second embodiment of the present invention will be described.

A flow rate regulating valve according to the second embodiment is generally designated by the reference numeral30-1inFIG.13. The flow rate regulating valve30-1shown inFIG.13is in a closed state. In the following description of the second embodiment, only configurations that are different from the first embodiment will be described, and descriptions of the same configurations as the first embodiment will be omitted.

InFIG.13, in the flow rate adjustment valve30-1according to the second embodiment, a biasing spring6C-1disposed in the co-rotation prevention mechanism6has a different configuration from the biasing springs6C of the co-rotation prevention mechanism6of the flow rate adjustment valve30in the first embodiment (FIGS.5to12).

In the first embodiment shown inFIGS.5to12, a plurality of biasing springs6C are provided at equal intervals in the circumferential direction of the shaft. In contrast, in the second embodiment shown inFIG.13, a single biasing spring6C-1is provided in a hollow portion of the co-rotation prevention member6A-1. The biasing spring6C-1is arranged to surround the shaft surrounding portion6AB-1.

The biasing spring6C-1has one end in contact with the bottom surface6A1-T (upper end surface: closed surface) of the hollow portion6A1-T in the co-rotation prevention member6A-1, and the other end in contact with the flange1E formed on the shaft1. The biasing spring6C-1constantly biases the shaft flange portion1E toward the opening adjustment dial4side (lower side inFIG.13) in the shaft axial direction. Other configurations and effects of the second embodiment shown inFIG.13are the same as those of the first embodiment shown inFIGS.5to12.

The illustrated embodiments are merely examples, and are not intended to limit the technical scope of the present invention. For example, the flow rate regulating valve of the present invention can be used in a filling device that fills devices other than FCVs with gaseous fuels other than hydrogen, and furthermore, can be used for gases other than fuel.

EXPLANATION OF SYMBOLS