JP7488475B2 - Flow Control Valve - Google Patents

Description

This disclosure relates to a flow control valve that controls the flow rate of a fluid, and is suitable for use, for example, in a purge valve that is disposed in a purge passage that communicates between a canister and an intake passage downstream of a throttle valve and controls the flow rate of air flowing through this purge passage.

As vehicles become more hybridized, there is a demand for the evaporated fuel adsorbed in the canister to flow (purge) into the engine's intake passage in a shorter time. On the other hand, as vehicles become more hybridized, the engine's intake negative pressure during purging decreases (approaching atmospheric pressure).

Therefore, using Patent Document 1 as the prior art, it has been proposed to use a first solenoid valve that switches between an on position that widely opens the purge passage and an off position that narrows the purge passage, in combination with a second solenoid valve that controls the duty ratio between when the coil in which the valve seat and the valve body are abutted and separated is not energized and is energized (Japanese Patent Application No. 2020-26491 (Japanese Patent Publication No. 2021-38738 ). The flow rate of the purge air is switched between large and small by the first solenoid valve, and the flow rate of the purge air is controlled by the second solenoid valve both at large and small flow rates.

However, because the second solenoid valve controls the duty ratio of the purge air flow rate not only at low flow rates but also at high flow rates, the sealing surface between the second valve body and the valve seat must be large to ensure the flow rate at high flow rates. This requires a large magnetic force when the second solenoid valve changes the valve seat from a closed state to an open state. Also, the first solenoid valve changes the flow area at a location other than the orifice restriction. Here, the orifice restriction has the greatest effect on the flow characteristics, so switching between large and small flow rates at a location other than the orifice restriction results in instability during switching.

JP 2008-291916 A

In view of the above, the present disclosure aims to make it possible to drive the second solenoid valve, which controls the duty ratio, with less power. It also aims to stabilize the flow characteristics when switching between large and small flow rates at the orifice restriction section, which has the greatest effect on the flow characteristics.

The first aspect of the present disclosure has a housing including an inflow passage through which a fluid flows in, an outflow passage through which the fluid flows out, a passage chamber formed between the outflow passage and the inflow passage, an orifice restriction portion formed on the outflow passage side of the passage chamber to limit the fluid flow rate, and a valve seat formed in the passage chamber.

The first aspect of the present disclosure has a first valve body that is disposed on the outflow passage side of the valve seat and cooperates with the orifice restriction portion to control the fluid flow rate, and a second valve body that is disposed on the passage chamber side of the valve seat and controls the fluid flow rate by abutting and disengaging from the valve seat.

The first aspect of the present disclosure includes a first coil that is excited by energization, a first stator core that forms a magnetic circuit when the first coil is energized, a first moving core that is arranged opposite the first stator core via a magnetic gap and moves when the first coil is energized and transmits the displacement associated with the movement to a first valve body, and a first solenoid valve that switches between an on position when the first coil is energized and an off position when the first coil is not energized, a second coil that is excited by energization, a second moving core that is arranged opposite the second stator core via a magnetic gap and moves when the second coil is energized and transmits the displacement associated with the movement to a second valve body, and a second solenoid valve that controls the duty ratio when the second coil is energized and when the second coil is not energized.

The first aspect of the present disclosure is that the second valve body is provided with a communication hole that communicates the passage chamber with the second solenoid valve, and is also provided with a diaphragm that is disposed in the passage chamber of the housing, and that establishes communication between the inlet passage and the outlet passage when the second valve body is separated from the valve seat, and that establishes non-communication between the inlet passage and the outlet passage when the second valve body is in contact with the valve seat.

According to the first aspect of the present disclosure, the second valve body is provided with a communication hole that connects the passage chamber and the second solenoid valve as a pressure cancellation mechanism, so that the pressure difference when the second valve body is opened and closed can be eliminated, and the second valve body can be opened and closed with a small magnetic force.

Furthermore, in the first aspect of the present disclosure, a diaphragm is provided which is disposed in the passage chamber of the housing and which establishes communication between the inlet passage and the outlet passage when the second valve body is separated from the valve seat, and which establishes a non-communicating state between the inlet passage and the outlet passage when the second valve body is in contact with the valve seat. Therefore, even if a communication hole is provided in the second valve body, the flow rate of the fluid can be accurately controlled.
In the first aspect of the present disclosure, the first valve body cooperates with the orifice throttle portion to switch the flow rate between a large flow rate position and a small flow rate position depending on the on and off positions of the second solenoid valve. Since the flow path area is switched by the orifice throttle portion, which has the greatest effect on the flow rate characteristics, the flow rate characteristics are stable when switching between a large flow rate and a small flow rate.

In the second aspect of the present disclosure, the first valve body includes a valve body throttle portion that cooperates with the orifice throttle portion to control the fluid flow rate, and a valve body passage portion through which the fluid passes. When the first solenoid valve is in the on position, the valve body throttle portion of the first valve body separates from the orifice throttle portion, and the fluid flows through the outer periphery of the valve body throttle portion and the valve body passage portion, and when the first solenoid valve is in the off position, the valve body throttle portion of the first valve body abuts against the orifice throttle portion, and the fluid flows through the valve body passage portion.

According to the second aspect of the present disclosure, a large flow rate can be provided when the first solenoid valve is in the on position, and the flow rate can be switched to a small flow rate when the first solenoid valve is in the off position. The switching between the large flow rate and the small flow rate in the first aspect of the present disclosure can be achieved by the valve body throttle portion and the valve body passage portion.

In the third aspect of the present disclosure, the first valve body is provided with a valve body throttling portion that cooperates with the orifice throttling portion to control the fluid flow rate. When the first solenoid valve is in the on position, the valve body throttling portion of the first valve body is separated from the orifice throttling portion, and the fluid flows at a large flow rate around the outer periphery of the valve body throttling portion, and when the first solenoid valve is in the off position, the valve body throttling portion of the first valve body is approached to the orifice throttling portion, and the fluid flows at a small flow rate around the outer periphery of the valve body throttling portion.

According to the third aspect of the present disclosure, the first solenoid valve can switch between a large flow rate and a small flow rate without providing a valve body passage portion in the first valve body, and the switching between a large flow rate and a small flow rate as in the first aspect of the present disclosure can be achieved while simplifying the configuration of the first valve body.

In the fourth aspect of the present disclosure, a rod is further provided to transmit the displacement of the first moving core of the first solenoid valve to the first valve body. By using the rod, it is possible to separate the position of the first solenoid valve from the position of the first valve body.

In the fifth aspect of the present disclosure, the first solenoid valve and the second solenoid valve are both arranged on the opposite side of the passage chamber from the orifice restriction portion. The first solenoid valve and the second solenoid valve can be arranged so as to overlap each other.

In the sixth aspect of the present disclosure, the first solenoid valve is disposed on the orifice throttle side of the passage chamber, and the second solenoid valve is disposed on the opposite side of the passage chamber from the orifice throttle portion. This increases the degree of freedom in the positioning of the first solenoid valve.

1 is a configuration diagram showing a purge system in which a flow control valve according to the present disclosure is used. FIG. 2 is a cross-sectional view of a flow control valve according to the first embodiment of the present disclosure. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 3 is a cross-sectional view of the flow control valve shown in FIG. 2 in a large flow rate state. FIG. 4 is a cross-sectional view of a flow control valve according to a second embodiment of the present disclosure. FIG. 6 is a cross-sectional view of the flow control valve shown in FIG. 5 in a large flow rate state. FIG. 11 is a cross-sectional view of a flow control valve according to a third embodiment of the present disclosure. FIG. 8 is a cross-sectional view of the flow control valve shown in FIG. 7 in a large flow rate state.

Figure 1 shows a usage mode when the flow control valve of the present disclosure is used as a purge valve 100. Purge air containing gasoline that has evaporated in the fuel tank 10 flows into the canister 13 via the inlet purge air passage 11, where the gasoline is adsorbed. Purge air containing gasoline from the canister 13 is supplied to the intake pipe 21 of the engine 20 via the outlet purge air passage 14. The purge valve 100 switches the supply of purge air flowing through the outlet purge air passage 14 on and off, and controls the flow rate when supplied.

The outlet purge air passage 14 opens downstream of the throttle valve 25 in the intake pipe 21, and the negative pressure of the intake air throttled by the throttle valve 25 draws in purge air containing gasoline from the canister 13. The canister 13 is provided with an air release valve 12 that opens to the atmosphere as needed. 24 is an air filter that removes foreign matter from the air drawn into the engine 20.

The on/off and flow rate of the purge valve 100 are controlled by the engine control unit 50. That is, since the gasoline adsorbed in the canister 13 is drawn into the engine 20 together with the gasoline from the fuel tank 10, the engine control unit 50 calculates the optimal engine combustion state and controls the flow rate of the purge valve 100. The engine control unit 50 also receives information from the vehicle ECU 60 about the state in which abnormal sounds generated by the control of the purge valve 100 are not easily conveyed to the occupants, and controls the on/off of the purge valve 100. For example, since abnormal sounds are not easily conveyed to the occupants when driving at high speeds, the vehicle ECU grasps the vehicle's driving conditions using a signal from the vehicle speed sensor 61.

The configuration of the purge valve 100 is described below for each embodiment.

First Embodiment
As shown in FIG. 2, the purge valve 100 has a first solenoid valve 130 and a second solenoid valve 150 arranged in series in a housing 110. The first solenoid valve 130 has a first coil 132 wound around a resin first bobbin 131 in a large number of turns. The housing 110 and the first bobbin 131 are made of resin such as polybutylene terephthalate (PBT) resin, polyphenylene sulfide (PPS) resin, nylon 66, or other resin. When the first coil 132 is energized by receiving a drive voltage from a connector (not shown), the first coil 132 is excited. In order to form a magnetic circuit at that time, a first yoke 133 made of iron is arranged on the outside of the first coil 132, and a first stator core 134 also made of iron is arranged on the inner periphery of the first coil 132.

The first stator core 134 has a cylindrical shape, and the first moving core 135, which is made of iron and has a cup shape, is movably arranged inside. The first stator core 134 has a narrowing portion 134a that narrows the magnetic circuit, so that a first magnetic gap 134b is formed between the first stator core 134 and the first moving core 135. When the first coil 132 is excited, the first moving core 135 is attracted upward in the figure to narrow this first magnetic gap 134b. The first spring 136 biases the first moving core 135 in a direction opposite to the direction of attraction. The first spring 136 is arranged between the first moving core 135 and the first spring support member 137.

The second solenoid valve 150 has roughly the same structure as the first solenoid valve 130. It includes a second bobbin 151, a second coil 152, a second yoke 153, a second stator core 154, and a second moving core 155.

The second stator core 154 also has a narrowing portion 154a that narrows the magnetic circuit, and a second magnetic gap 154b is formed between the second stator core 154 and the second moving core 155. When the second coil 152 is excited, the second moving core 155 is attracted downward in the figure to narrow the second magnetic gap 154b. The second spring 156 biases the second moving core 155 in a direction opposite to the direction of attraction. The second spring 156 is disposed between the second moving core 155 and the second spring support member 157.

A passage chamber 160 is formed in the upper part of the housing 110 in FIG. 2. The housing 110 also has an inflow passage 161 to which the hose forming the outlet side purge air passage 14 is connected, and the inflow passage 161 opens into the passage chamber 160. A cylindrical orifice restriction portion 162 is formed to protrude from the passage chamber 160, and the lower end of the orifice restriction portion 162 in FIG. 2 forms a valve seat 163. The orifice restriction portion 162 restricts the passage diameter of the purge air so as to work together with the first valve body 170 described later to restrict the flow of the purge air, and this orifice restriction portion 162 has the greatest effect on the flow rate characteristics of the purge air flowing through the purge valve 100.

The orifice restriction 162 also communicates with the outflow passage 164, and the purge air that flows from the inflow passage 161 into the passage chamber 160 flows through the valve seat 163 and the orifice restriction 162 into the outflow passage 164. A hose that forms the outlet-side purge air passage 14 is connected to the outflow passage 164, and the purge air is sucked from the outflow passage 164 through the hose to the downstream of the throttle valve 25 of the intake pipe 21.

The first valve body 170 has a cylindrical shape with a valve body passage portion 171 through which purging air passes. The lower side of the outer periphery of the first valve body 170 in FIG. 2 is shaped so that it can be seated against the orifice throttling portion 162, forming a valve body throttling portion 174. The first valve body 170 communicates with the first moving core 135 of the first solenoid valve 130 via a rod 172. As shown in FIG. 3, the rod 172 and the first valve body 170 are connected via an arm portion 173.

A second valve body 180 is disposed in the passage chamber 160 at a location facing the valve seat 163. The second valve body 180 is baked and fixed to the second moving core 155 of the second solenoid valve 150, and is made of an elastic material such as rubber material to ensure sealing with the valve seat 163. In this disclosure, fluororubber is used for its gasoline resistance.

A communication hole 185 is formed in the second valve body 180, and the rod 172 passes through this communication hole 185. In addition, the communication hole 185 balances the pressure in the passage chamber 160 and the pressure of the second solenoid valve 150.

A diaphragm 181 that seals between the second valve body 180 and the second solenoid valve 150 is disposed in the passage chamber 160. The diaphragm 181 is made of a flexible rubber material and has a ring shape. The inner circumference 182 of the diaphragm 181 is integrally formed with the second valve body, and the outer circumference 183 is engaged with the passage chamber 160 of the housing 110.

Next, the operation of the purge valve 100 having the above configuration will be described. In the off position where the first coil 132 of the first solenoid valve 130 is not energized, the first coil 132 is not excited, and the first moving core 135 is urged by the first spring 136 in a direction away from the first stator core 134. In this state shown in FIG. 2, the first moving core 135 is urged toward the bottom plate 111 of the housing 110. In this state, the outer periphery of the first valve body 170 is seated on the orifice throttling portion 162. Therefore, the flow from the passage chamber 160 toward the outflow passage 164 is only through the valve body passage portion 171 of the first valve body 170. As a result of the air flow path being throttling in this way, the flow rate along the purge valve 100 is small, and in this disclosure, it is about 60 liters per minute.

At this small flow rate, the flow rate of the purge air that further flows through the purge valve 100 is controlled by the second valve body 180. When the second coil 152 of the second solenoid valve 150 is excited, a magnetic attraction force is generated in the second magnetic gap 154b between the second stator core 154 and the second moving core 155, and since this magnetic attraction force exceeds the biasing force of the second spring 156, the second moving core 155 moves toward the second stator core 154. As a result, the second valve body 180 leaves the valve seat 163, and the purge air in the passage chamber 160 flows into the valve body passage portion 171 of the first valve body 170. In the state shown in FIG. 2, the second coil 152 is excited and the second valve body 180 opens the valve seat 163.

When the current to the second coil 152 is stopped from the state shown in FIG. 2, the second spring 156 displaces the second moving core 155 approximately 1.5 mm upward in the figure, and the second valve body 180 abuts against the valve seat 163. As a result, the flow of purge air from the passage chamber 160 toward the outflow passage 164 is blocked.

The second solenoid valve 150 performs duty ratio control between a fully open state in which the valve seat 163 is opened and a fully closed state in which the valve seat 163 is closed. A duty ratio of 100% results in the maximum flow rate during low flow rates, and a duty ratio of 0% blocks the flow of purge air. The time for which duty ratio control is performed is approximately 10 Hertz (0.1 seconds), and the ratio between the fully open state and the fully closed state is varied within this time.

The above is the flow control of the purge valve 100 at low flow rates, but at high flow rates, the first coil 132 of the first solenoid valve 130 is energized to the on position. As a result, the first coil 132 is excited, and an attractive force is generated in the first magnetic gap 134b between the first stator core 134 and the first moving core 135 of the first solenoid valve 130. This attractive force is greater than the first spring 136, and the first moving core 135 is pulled upward as shown in FIG. 4.

The movement of the first moving core 135 is transmitted to the first valve body 170 via the rod 172, and the first valve body 170 is separated from the orifice throttling portion 162 by about 3 millimeters. Therefore, the purge air that has passed through the valve seat 163 flows not only through the valve body passage portion 171 of the first valve body 170, but also through the outer periphery of the first valve body 170 to the outflow passage 164, allowing a large flow rate to flow. In this disclosure, about 200 liters of purge air flows per minute at a large flow rate. Thus, the orifice throttling portion 162 has the greatest effect on the flow rate characteristics of the purge air passing through the purge valve 100. In this disclosure, the orifice throttling portion 162 and the first valve body 170 work together to switch the flow area of the orifice throttling portion 162 between a large flow rate and a small flow rate, so that the flow rate switching can be performed most efficiently. Therefore, the characteristics when switching between a large flow rate and a small flow rate are also stable.

Even in this state where a large flow rate is being flowed, the flow rate of the purge air is controlled by the second solenoid valve 150. Duty ratio control is performed in the same way as for the control at low flow rates. That is, the second solenoid valve 150 performs duty ratio control between a fully open state where the valve seat 163 is open and a fully closed state where the valve seat 163 is closed, with a duty ratio of 100% being the maximum flow rate at low flow rates, and a duty ratio of 0% blocking the flow of purge air. Figure 4 shows the fully open state where the second solenoid valve 150 opens the valve seat 163.

However, the control to cut off the flow of purge air is actually performed when the flow rate is low. Therefore, the duty ratio is set so that the minimum flow rate of purge air when a high flow rate is being flowed is not 0%, but is about 60 liters per minute, the same as the maximum flow rate of purge air when a low flow rate is being flowed. In this case, the duty ratio is about 30 percent.

In the present disclosure, whether control at a low flow rate or control at a high flow rate, the flow rate of the purge air is controlled by controlling the duty ratio of the second solenoid valve 150. Here, in order to control the flow rate of the purge air at a high flow rate, the diameter of the valve seat 163 needs to be set large so that a sufficient amount of purge air can flow. Therefore, if the second valve body 180 is structured to block the passage chamber 160 and the second solenoid valve 150, a differential pressure will be applied to the second valve body 180.

Normally, the second solenoid valve 150 exists under atmospheric pressure, while when the second valve body 180 closes the valve seat 163, the second valve body 180 is subjected to the intake negative pressure downstream of the throttle valve 25. This intake negative pressure varies from a negative pressure close to atmospheric pressure to a large negative pressure of about 80 kilopascals. Therefore, if the second valve body 180 is enlarged as described above to receive this intake negative pressure, a large excitation force is required for the second coil 152 of the second solenoid valve 150, and the number of turns of the second coil 152 must be increased. This, in turn, results in an increase in the size of the purge valve 100.

In contrast, in the present disclosure, the passage chamber 160 and the second solenoid valve 150 are connected by the communication hole 185, so the second valve body 180 is not subjected to a pressure difference between the front and rear. All that is required is to generate an excitation force that can overcome the biasing force of the second spring 156 and attract the second moving core 155 toward the second stator core 154, and an example magnetic force of about 1 Newton is sufficient. This allows the second coil 152 to be made smaller. In particular, since the second solenoid valve 150 performs duty ratio control, the second valve body 180 can move smoothly between the fully open position and the fully closed position without being affected by the pressure difference between the front and rear, which leads to improved controllability of the flow rate.

Even if the second valve body 180 has a communication hole 185, the sealing performance when the second valve body 180 abuts against the valve seat 163 is ensured by the diaphragm 181. That is, the outer periphery of the diaphragm 181 is engaged by the housing 110, and the inner periphery of the diaphragm 181 is integrated with the second valve body 180, so that when the second valve body 180 is seated on the valve seat 163, the passage chamber 160 (inflow passage 161) and the outflow passage 164 are blocked by the diaphragm 181.

Second Embodiment
In the first embodiment described above, the first valve body 170 is formed with the valve body passage 171, and the valve body throttle portion 174 is shaped so as to be able to seat on the orifice throttle portion 162. However, as in the second embodiment shown in Figures 5 and 6, it may be shaped simply. The first valve body 170 in the second embodiment is conical in shape, and no valve body passage is formed therein. The outer periphery forms the valve body throttle portion 174, but does not come into contact with the orifice throttle portion 162.

At low flow rates, as shown in FIG. 5, the first coil 132 of the first solenoid valve 130 is not excited, and the first moving core 135 is pushed downward by the first spring 136 and held by the bottom plate 111 of the housing 110. As a result, the conical first valve body 170 approaches the orifice restriction portion 162, narrowing the flow path between the first valve body 170 and the orifice restriction portion 162. The gap between them is set so that the flow rate of the purge air is a low flow rate of about 60 liters per minute. In this disclosure, it is set so that the flow path area is equivalent to a hole with a diameter of about 1.5 millimeters.

At high flow rates, as shown in FIG. 6, the first coil 132 of the first solenoid valve 130 is excited. This causes the first moving core 135 to be pulled up toward the first stator core 134, and the first valve body 170 is also pushed up through the rod 172. As a result, the conical first valve body 170 separates from the orifice restriction portion 162, and a large flow rate of purge air flows between the first valve body 170 and the orifice restriction portion 162. The gap between the first valve body 170 and the orifice restriction portion 162 at this time is set to provide a large flow rate of approximately 200 liters per minute, and in this disclosure, is set to have a flow area equivalent to a hole with a diameter of approximately 4 millimeters.

Note that both Figures 5 and 6 show the second solenoid valve 150 in an excited state with the second valve body 180 in a fully open position. The second solenoid valve 150 is duty-ratio controlled in the same way as in the first embodiment.

Third Embodiment
In the above-mentioned embodiment, the first solenoid valve 130 and the second solenoid valve 150 are disposed in one housing 110 and are disposed on the same side with respect to the passage chamber 160. In the third embodiment, as shown in Figures 7 and 8, the housing 110 is separated into a first housing 112 in which the first solenoid valve 130 is disposed and a second housing 113 in which the second solenoid valve 150 is disposed, with a connecting housing 114 interposed therebetween. The inflow passage 161 and the passage chamber 160 are formed in the second housing 113, and the passage chamber 160 and the second solenoid valve 150 are communicated with each other through a communication hole 185 of the second valve body 180, so that no pressure difference occurs before and after the second valve body 180, as in the above-mentioned embodiment.

Figure 7 shows a small amount state in which the first coil 132 of the first solenoid valve 130 is not excited. In this state, the first moving core 135 is pushed downward in the figure by the urging force of the first spring 136, and the valve body throttle portion 174 on the outer periphery of the first valve body 170 is seated on the orifice throttle portion 162. Therefore, the flow of purge air is only through the valve body passage portion 171 of the first valve body 170. Although the position of the rod 172 is different, the operation is the same as in the first embodiment shown in Figure 2. In the third embodiment, an O-ring 175 is placed on the valve body throttle portion 174 on the outer periphery of the first valve body 170 in order to improve the sealing performance when the first valve body 170 is seated and to mitigate the impact when it is seated. Of course, an elastic member made of a rubber material or the like may be placed instead of the O-ring 175.

Figure 8 shows the high flow state, in which the first coil 132 of the first solenoid valve 130 is excited. As a result, the magnetic attraction force generated in the first magnetic gap 134a pulls the first moving core 135 upward in the figure, and purged air flows from both the valve body throttle portion 174 on the outer periphery of the first valve body 170 and the valve body passage portion 171.

Figures 7 and 8 both show the second solenoid valve 150 in an excited state with the second valve body 180 in a fully open position, and the second solenoid valve 150 is duty-ratio controlled, as in the first and second embodiments described above.

As a modification of the third embodiment, if the distance between the first valve body 170 and the first moving core 135 of the first solenoid valve 130 is shortened, it is also possible to eliminate the rod 172 and directly displace the first valve body 170 using the first moving core 135.

Other Embodiments
In the above disclosure, the second valve body 180 and the diaphragm 181 are integrally molded from the same fluororubber, but they may be separate members. Also, in the above disclosure, the second valve body 180 is fixed to the second moving core 155 of the second solenoid valve 150 by baking, but a connecting member may be interposed between the second moving core 155 and the second valve body 180.

In addition, the purge valve 100 is a preferred example of the use of the flow control valve of the present disclosure, but the present disclosure has a wide range of uses as a control valve that can switch between high and low flow rates and control both high and low flow rates.

REFERENCE SIGNS LIST 100 Purge valve 110 Housing 130 First solenoid valve 150 Second solenoid valve 160 Passage chamber 161 Inflow passage 162 Orifice restriction portion 163 Valve seat 170 First valve body 180 Second valve body 185 Communication hole

Claims (6)

a housing including an inflow passage through which a fluid flows in, an outflow passage through which the fluid flows out, a passage chamber formed between the outflow passage and the inflow passage, an orifice throttle portion formed on the outflow passage side of the passage chamber for restricting a fluid flow rate, and a valve seat formed in the passage chamber;
a first valve body that is disposed closer to the outlet passage than the valve seat and cooperates with the orifice throttle portion to control a fluid flow rate;
a second valve body that is disposed closer to the passage chamber than the valve seat and that abuts against and separates from the valve seat to control a fluid flow rate;
a first solenoid valve including a first coil which is excited by energization, a first stator core which forms a magnetic circuit when the first coil is energized, and a first moving core which is disposed opposite the first stator core across a magnetic gap and moves when the first coil is energized and transmits a displacement associated with the movement to the first valve body, the first solenoid valve switching between an on position when the first coil is energized and an off position when the first coil is not energized;
a second coil which is excited by energization; a second moving core which is disposed opposite the second stator core via a magnetic gap and which moves by energization of the second coil and transmits a displacement associated with the movement to the second valve body; and a second solenoid valve which performs duty ratio control when the second coil is energized and when the second coil is not energized,
The second valve body is provided with a communication hole for communicating the passage chamber with the second solenoid valve,
a diaphragm that is disposed in the passage chamber of the housing, the diaphragm establishing a communication state between the inlet passage and the outlet passage when the second valve body is separated from the valve seat, and establishing a communication state between the inlet passage and the outlet passage when the second valve body is in contact with the valve seat. the first valve body includes a valve body throttle portion that cooperates with the orifice throttle portion to control a fluid flow rate, and a valve body passage portion through which a fluid passes,
When the first solenoid valve is in the on position, the valve body throttle portion of the first valve body is separated from the orifice throttle portion, and the fluid flows through the outer periphery of the valve body throttle portion and the valve body passage portion,
2. The flow control valve according to claim 1, wherein when the first solenoid valve is in the off position, the valve body throttle portion of the first valve body abuts against the orifice throttle portion, and fluid flows through the valve body passage portion. the first valve body includes a valve body throttle portion that cooperates with the orifice throttle portion to control a fluid flow rate;
When the first solenoid valve is in the on position, the valve body throttle portion of the first valve body is separated from the orifice throttle portion, and a large amount of fluid flows around the outer periphery of the valve body throttle portion.
2. The flow control valve according to claim 1, wherein, when the first solenoid valve is in the off position, the valve body throttle portion of the first valve body approaches the orifice throttle portion, and a small amount of fluid flows around the outer periphery of the valve body throttle portion. 4. The flow control valve according to claim 1, further comprising a rod that transmits the displacement of the first moving core of the first solenoid valve to the first valve body. 5. The flow control valve according to claim 1, wherein the first solenoid valve and the second solenoid valve are arranged to overlap each other at positions opposite to the orifice throttle portion with respect to the passage chamber. the first solenoid valve is disposed at a position on the orifice throttle portion side with respect to the passage chamber,
5. The flow control valve according to claim 1, wherein the second solenoid valve is disposed on a side of the passage chamber opposite to the orifice throttle portion.

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