JP6395294B2 - Check valve - Google Patents

Description

  The present invention includes a valve casing having a first flow path through which a liquid medium flows and a valve seat formed therein, and a valve casing that is located in the valve casing and moves across an open / close position of the valve in accordance with the liquid pressure of the liquid medium. And a first urging force for urging the valve body in a valve closing direction that opposes the direction in which the liquid medium flows and is seated on the valve seat so as to close the valve. A valve mechanism having means, and when the fluid pressure of the liquid medium existing on the upstream side of the valve seat exceeds the urging force of the first urging means when viewed in the flow direction of the liquid medium, the valve body The present invention relates to a check valve that moves in a direction away from a valve seat and opens.

  In a vehicle equipped with a compression self-ignition engine typified by a diesel engine, the fuel in the fuel tank is pumped and supplied to the common rail as high-pressure fuel by a high-pressure pump when the engine is in operation, and then the high-pressure accumulated in the common rail. After being supplied to the injector (fuel injection device) as fuel, it is injected into each cylinder of the engine from the injection hole of this injector. Normally, the fuel that has been supplied into the injector but remains without being injected is returned to the fuel tank as excess fuel via a predetermined pipe line. For example, in Patent Document 1, an injector return pipe (first return pipe) that returns excess fuel that has not been injected to the fuel tank is connected to the top of the injector, and a check valve is connected to the first return pipe. The structure which provided is disclosed. The check valve keeps the upstream fuel pressure in the first return pipe constant, and opens when the fuel pressure in the first return pipe upstream of the check valve exceeds a predetermined value. It is configured. Further, in the start-up control device for the compression self-ignition engine described in Patent Document 1, the first return pipe is located downstream of the check valve, and the regulator pipe (first pipe) returns the excess fuel from the high-pressure pump to the fuel tank. 2 return pipes) and a return pipe (third return pipe) for returning excess fuel from the common rail to the fuel tank.

  In the apparatus described in Patent Document 1 having such a configuration, for example, when the driver releases the accelerator while the vehicle is running and the vehicle is in a coasting state, that is, a non-injecting state in which the injector does not inject fuel, the check valve is The valve closed state is maintained in order to keep the fuel pressure in the first return line between the injector and the injector constant. However, since the high pressure pump continues to pump fuel required for pressure control in the common rail into the common rail even in the coasting state of the vehicle, as a result of continued pumping of fuel by the high pressure pump, there is excess fuel that is not used for pressure control. The excess fuel generated in the high-pressure pump needs to be returned as return fuel from the high-pressure pump to the fuel tank through the second return line. When returning the return fuel to the fuel tank through the second return line, the return fuel flowing in the second return line is likely to generate pressure pulsation due to the influence of the plunger operation in the high pressure pump. There is also a tendency to affect the pressure in the first return line communicating with the second return line.

  That is, when the return fuel flowing in the second return pipe pulsates, pressure fluctuations, particularly negative pressure, may also occur in the first return pipe. In such a case, the valve body in the check valve disposed in the first return pipe is separated from the valve seat by the negative pressure suction force regardless of the fuel pressure existing upstream of the valve seat in the check valve. Or the valve malfunctions due to or swinging, and the fuel existing on the upstream side of the check valve flows out to the fuel tank through the check valve, and the check valve in the first return pipe There was a tendency for the upstream fuel pressure to fall below a desired value. When the fuel pressure on the upstream side of the check valve is lower than the desired value and the fuel injection is resumed by the injector when the driver depresses the accelerator again, the components inside the injector, such as an amateur, are oil films. Since it operates in the cut state, there is a problem that the amateur wears and the fuel injection amount may change due to this wear.

JP 2013-113162 A

  An object of the present invention is to provide an appropriate valve body locking member that locks the valve body in a closed state, thereby preventing abnormal movement of the valve body due to pressure pulsation generated on the outlet side of the check valve. It is to provide a check valve that can.

  In order to achieve the above object, the gist of the present invention is as follows.

(1) A valve casing formed inside with a first flow path through which a liquid medium flows and a valve seat, and a valve casing that is located in the valve casing and moves across the open / close position of the valve in accordance with the liquid pressure of the liquid medium And a first valve body for urging the valve body in a valve closing direction that is in a direction that opposes the direction in which the liquid medium flows and that is seated on the valve seat so as to be closed. A valve mechanism having an urging means, and the liquid pressure of the liquid medium existing on the upstream side of the valve seat exceeds the urging force of the first urging means when viewed in the flow direction of the liquid medium. When the check valve is a check valve that moves in a direction away from the valve seat and opens, the position of the first flow path between the inlet of the check valve and the valve seat A second flow path having a branch port branching from the first flow path is formed, located in the second flow path, A pressure receiving portion for blocking the flow of the liquid medium entering the two flow paths, and a movably disposed in the first flow path, and moved to a position in contact with the valve body in the valve-closed state. A valve body locking member that has a locking portion that is integral with the pressure receiving portion and that locks the valve body, and a direction in which the valve body locking member resists the liquid pressure of the liquid medium that acts on the pressure receiving portion. And a second urging means for urging the locking portion to move in a direction in which the valve body is locked, and the valve body locking member is provided in the closed state. The valve body is locked to prevent abnormal movement of the valve body due to pressure pulsation generated on the outlet side of the check valve, and the upstream side of the valve seat in the first flow path Before the valve body moves in the valve opening direction based on the liquid pressure of the liquid medium, the valve body enters the second flow path. The pressure receiving part is first pressed and moved by the action of the fluid pressure of the body medium, and the locking part is configured to move from the locking position of the valve body to the locking release position. Check valve.

(2) The check valve according to (1), wherein the urging force of the second urging means is smaller than the urging force of the first urging means.

(3) The movement of the engagement portion between the engagement position and the engagement release position of the valve body is a slide movement in a direction crossing the flow direction of the liquid medium in the first flow path. The check valve according to (1) or (2) above, characterized in that

(4) The check valve according to any one of (1) to (3), wherein the check valve is disposed in a fuel return line for returning fuel from the fuel injection device to the fuel tank. Check valve.

(5) The valve body is a sphere,
The check valve according to any one of (1) to (4), wherein each of the first urging means and the second urging means is a compression spring.

  According to the present invention, a second flow path having a branch port branched from the first flow path is formed at a position between the inlet of the check valve and the valve seat in the first flow path. And a pressure receiving portion that blocks the flow of the liquid medium that enters the second flow path, and is movably disposed in the first flow path, and moves to a position in contact with the valve body in the closed state. And a valve body locking member having a locking portion integrated with the pressure receiving portion, and a direction in which the valve body locking member resists the liquid pressure of the liquid medium acting on the pressure receiving portion. And a second urging means for urging the locking portion to move in the direction in which the valve body is locked, and the valve body locking member is configured to lock the valve body in a closed state. The abnormal movement of the valve body due to the pressure pulsation generated on the outlet side of the check valve can be prevented, and the valve body locking member can be disposed upstream of the valve seat in the first flow path. Before the valve body moves in the valve opening direction based on the liquid pressure of the liquid medium existing in the second medium, the pressure receiving portion is first pressed and moved by the action of the liquid pressure of the liquid medium entering the second flow path. By configuring the stop portion to move from the locking position of the valve body to the locking release position, the normal operation of the check valve can be performed without hindrance.

FIG. 1 is a schematic diagram showing a fuel piping system of a vehicle. 2 (a) and 2 (b) show a state in which the valve body locking member constituting the check valve of the present invention is moved to a position in contact with the valve body to lock the valve body. FIG. 2A is a longitudinal sectional view of the check valve, and FIG. 2B is a sectional view taken along the line I-I shown in FIG. FIG. 3 is a cross-sectional view taken along the line I-I showing a state immediately after the valve body locking member constituting the check valve shown in FIG. 2A slides to the unlocking position of the valve body. 4 (a), 4 (b), and 4 (c) show the first channel and the second channel so that the internal structure can be seen from three different directions, and FIG. 4 (a) is a plan view. FIG. 4B is a side perspective view, and FIG. 4C is a rear perspective view. FIG. 5 is an exploded perspective view of a representative check valve according to the present invention. FIG. 6 is a plan view of the check valve according to the present invention so as to show the positional relationship between the branch port of the second flow path and the through hole through which the valve body locking member slides. FIG. 7 is a longitudinal sectional view for explaining a conventional check valve.

  Next, an embodiment of a check valve according to the present invention will be described below with reference to the drawings.

  FIG. 1 illustrates an embodiment when the check valve 20 of the present invention is applied to a common rail fuel injection system 10. The common rail fuel injection system 10 stores fuel that is a liquid medium. Fuel tank 11, fuel filter 12, fuel pump 13, common rail 15 having pressure control valve 14, fuel injection device 16, check valve 20 according to the present invention, and pipes connecting them are shown. FIG. 2A is a longitudinal sectional view of the check valve 20 according to the present invention. FIG. 2A is a state in which the valve body locking member 50 is in the locked position of the valve body 41, that is, the check valve 20 2 (b) is a cross-sectional view taken along the line I-I shown in FIG. 2 (a), and FIG. 3 shows that the valve body locking member 50 is connected to the valve body 41. Immediately after moving to the unlocking position of 4B is a cross-sectional view on the line I-I similar to FIG. 2B when the check valve 20 is in an open state, and FIGS. 4A to 4C are first views of the check valve 20. The flow path 22 and the second flow path 27 are shown so that the internal structure can be seen from three different directions, with FIG. 4 (a) being a plan perspective view and FIG. 4 (b) being a side perspective view and FIG. (C) is a rear perspective view.

  The fuel pump 13 shown in FIG. 1 includes a feed pump for pumping fuel from the fuel tank 11 through the fuel filter 12 and a high-pressure pump for pressurizing the pumped fuel (liquid medium) and pumping it to the common rail 15. The high-pressure fuel discharge amount is adjusted by a suction adjustment valve (not shown) provided on the fuel suction side of the fuel pump 13. In the present invention, the fuel pump 13 is not limited to such a configuration. For example, the feed pump and the high-pressure pump may be provided separately and independently.

  The common rail 15 is a pressure vessel for accumulating high-pressure fuel pumped from the fuel pump 13 and distributing a predetermined amount of high-pressure fuel to each fuel injection device (injector) 16, and controls the pressure in the common rail 15. Therefore, a pressure control valve 14 is provided. The pressure control valve 14 is, for example, a solenoid pressure that adjusts the pressure in the common rail 15 (adjusts the amount of fuel discharged) by adjusting the opening of the valve by an engine control unit (ECU) (not shown). A control valve is preferred.

  The fuel injection device 16 is for injecting high-pressure fuel accumulated in the common rail 15 into a cylinder of an internal combustion engine (not shown), and a back pressure relief mechanism (not shown) for opening and closing the injection hole. have. The back pressure relief mechanism is configured to allow high pressure fuel in a back pressure chamber (not shown) to escape to the first return line 17 (that is, to cause dynamic leak) during fuel injection. The injection method of the fuel injection device 16 is not particularly limited, and for example, either a piezo type fuel injection device using a piezo actuator or an electromagnetic solenoid type fuel injection device may be used.

  The first return pipe 17 extends from the back pressure relief mechanism of the fuel injection device 16 toward the fuel tank 11 and is used to return excess fuel discharged from the back pressure relief mechanism to the fuel tank 11. Thus, a check valve 20 is provided at an arbitrary position of the first return pipeline 17. Further, the first return pipe 17 has an end portion on the downstream side of the check valve 20 as viewed in the direction in which excess fuel flows, and excess fuel that has not been used for controlling the common rail pressure is supplied from the fuel pump 13. A second return line 18 that returns to the fuel tank 11 and a third return line 19 that returns the fuel released from the common rail 15 through the pressure control valve 14 to the fuel tank 11 are connected.

  The check valve 20 is mainly composed of a valve casing 21 and a valve mechanism 40, and is discharged from the back pressure relief mechanism of the fuel injection device 16 to the first return line 17 to become a hydraulic pressure higher than a predetermined pressure. It is provided to allow excess fuel to flow and to prevent fuel flow in the opposite direction. In the check valve 20 according to the embodiment of the present invention, the hydraulic pressure of the excess fuel returning from the fuel injection device 16 to the fuel tank 11 is mainly set at a predetermined level in the portion of the first return pipe 17 upstream of the check valve 20. When the hydraulic pressure in the upstream portion of the first return line 17 exceeds a predetermined pressure value, the check valve is provided to maintain the pressure range (for example, 0.3 to 0.8 bar (relative pressure)). 20 is in a valve open state, and is configured to allow excess fuel (liquid medium) to flow out to the downstream side of the first return line 17 and return to the fuel tank 11.

  In the valve casing 21 shown in FIG. 2, a first flow path 22 through which a liquid medium, for example, excess fuel returning from the fuel injection device 16 to the fuel tank 11 flows, and a valve seat 23 are formed. An inflow port 24 and an outflow port 25 are provided on each end wall of the valve casing 21 in the flow direction of the liquid medium (indicated by the white arrow F in FIG. 2), and the first flow path 22 is The valve casing 21 is formed so as to penetrate between the inlet 24 and the outlet 25. Further, the valve seat 23 is formed at an arbitrary position of the first flow path 22 between the inlet 24 and the outlet 25. In the illustrated embodiment, the shape of the valve seat 23 is such that the diameter of the valve seat 23 is reduced toward the inflow port 24 so that the inner diameter is smaller than the outer diameter of the valve body 41, and the overall shape is substantially a truncated cone. Although it is shown, the shape may be any shape as long as the valve body 41 can be stably seated on the valve seat 23 in the closed state, and is not limited to this shape.

  Further, a valve mechanism 40 is located in the valve casing 21, and the valve mechanism 40 includes a valve body 41 that can move over the open / closed position of the valve in accordance with the hydraulic pressure of the excess fuel, and the valve body 41 is connected to the excess fuel. Has a first urging means 42 for urging in a valve closing direction which is in a direction opposite to the direction F in which the gas flows and which is seated on the valve seat 23 so as to be closed. For example, in the illustrated embodiment, the valve body 41 is a sphere, and the first urging means 42 is a first compression spring. The valve body 41 moves in the first flow path 22 based on the force relationship between the hydraulic pressure in the first return pipe 17 and the urging force of the first compression spring 42, thereby opening and closing the check valve 20. The state can be controlled appropriately. The valve body 41 may be configured so as to be seated on the valve seat 23 and achieve a valve closing state, and the configuration is not limited to a sphere. One end of the first compression spring 42 is closely supported by the inner wall of the valve casing 21 on the outlet 25 side in the first flow path 22, and the other end is pressed and brought into contact with the valve body 41 by a spring force. A biasing force is applied to the valve body 41 so that the valve closed state can be achieved by seating 41 on the valve seat 23. The first urging means 42 only needs to be configured to apply a urging force that presses the valve body 41 against the valve seat 23, and the configuration is not limited to the compression spring.

  The check valve 20 is configured such that when the excess fuel hydraulic pressure existing on the upstream side of the valve seat 23 exceeds the urging force of the first urging means 42 when viewed in the flow direction F of excess fuel, the valve element 41 It moves in the direction away from the valve seat 23 and enters the valve open state. That is, like the known check valve, the check valve 20 changes the flow direction F of the excess fuel only in one direction from the inlet 24 on the upstream side of the valve seat 23 to the outlet 25 on the downstream side of the valve seat 23. In the opposite flow, the first flow path 22 is configured to be closed by the valve body 41, and the excess fuel according to the pressure of the excess fuel existing on the upstream side of the valve seat 23. Is allowed to flow only in the flow direction F, and the pressure of the excess fuel existing on the upstream side of the valve seat 23 can be controlled appropriately.

  And the main characteristic on the structure of this invention originates in the pressure pulsation which arises in the outflow port 25 side of the check valve 20 by providing the valve body latching member 50 which can contact the valve body 41 in the valve casing 21. FIG. More specifically, the abnormal movement of the valve body 41 is prevented. More specifically, the first flow path 22 is positioned at a position between the inlet 24 of the check valve 20 and the valve seat 23 in the first flow path 22. A second flow passage 27 having a branch port 26 branched from the pressure passage 51, located in the second flow passage 27, and blocking the flow of the liquid medium entering the second flow passage 27, and And a locking portion 52 integrally formed with the pressure receiving portion 51, which is movably disposed in the first flow path 22, moves to a position in contact with the valve body 41 in the valve-closed state, and locks the valve body 41. A valve body locking member 50 and a liquid that operates the valve body locking member 50 on the pressure receiving portion 51. And a second urging means 53 for urging the urging portion 52 so as to move in a direction against the body fluid pressure and in a direction to engage the valve body 41, 50 locks the valve body 41 in the closed state, prevents abnormal movement of the valve body 41 due to pressure pulsation generated on the outlet 25 side of the check valve 20, and the valve in the first flow path 22. Before the valve body 41 moves in the valve opening direction based on the liquid pressure of the liquid medium existing on the upstream side of the seat 23, the pressure receiving portion 51 is moved by the action of the liquid pressure of the liquid medium that enters the second flow path 27. The check valve 20 is configured so that the locking portion 52 moves from the locking position of the valve body 41 to the locking release position by being pressed and moved first. By adopting the above configuration, the present invention occurs on the outlet 25 side of the check valve 20 when the hydraulic pressure upstream of the valve seat 23 is low and the check valve 20 is kept closed. Even if a negative pressure based on pressure pulsation acts on the valve body 41 of the check valve 20, the locking portion 52 of the valve body locking member 50 is on the side of the valve body 41 that contacts the first biasing means 42. Since the valve body 41 is locked at the position in contact with the portion (the back side portion of the valve body 41), the abnormal movement of the valve body 41 in the valve opening direction can be prevented. Since the malfunction of the check valve 20 can be prevented, an inconvenient drop in the liquid pressure of the liquid medium existing upstream from the valve seat 23 is avoided, and the components between the components due to the oil film breakage in the components in the fuel injection device 16 are avoided. Prevents wear due to friction and changes in the injection amount due to wear. It can ensure long-term stable injection quantity of fuel injection without causing.

  The second flow path 27 is formed to displace the valve body locking member 50 so as to prevent the valve body 41 of the check valve 21 from moving abnormally. 22 has a branch port 26 branched from the first flow path 22 at a position between the inlet 24 of the check valve 20 and the valve seat 23. In addition, the flow of the liquid medium (excess fuel) entering the second flow path 27 is blocked in the second flow path 27 and can move in the second flow path 27 according to the liquid pressure of the liquid medium. As described above, the pressure receiving portion 51 of the valve body locking member 50 is disposed in a liquid-tight manner, and the pressure receiving portion 51 includes a pressure receiving surface 55 that faces the flow of excess fuel. For this reason, the 2nd flow path 27 turns into a dead end flow path by arrange | positioning the pressure receiving part 51 of the valve body latching member 50. FIG.

  Since the pressure receiving part 51 is configured so that excess fuel in the second flow path 27 does not flow from the upstream side to the downstream side or from the downstream side to the upstream side across the pressure receiving part 51, the outer peripheral surface of the pressure receiving part 51 In addition, it is preferable to provide an elastic seal member that is in close contact with the inner wall of the second flow path 27 and does not hinder the movement of the pressure receiving portion 51 in the second flow path 27.

  In addition, the valve body locking member 50 is movably disposed in the first flow path 22, moves to a position where it contacts the valve body 41 in the closed state, and locks the valve body 41. It has the latching | locking part 52 which makes an integral.

  Furthermore, the valve body locking member 50 is configured so that the pressure receiving portion 51 is located in the second flow path 27 and the locking portion 52 is located in the first flow path 22. A through hole 36 that communicates the second flow path 27 and the first flow path 22 is provided at a position where the back surface side portion of the valve body 41 in the valve state can be contacted, and the locking portion 52 of the valve body locking member 50 By being inserted into the through hole 36, it is possible to contact the back side portion of the valve body 41 in the closed state, which is located in the first flow path 22.

  In the second urging means 53, the locking portion 52 moves in a direction in which the valve body locking member 50 resists the liquid pressure of the liquid medium acting on the pressure receiving portion 51 and the valve body 41 is locked. It is provided to energize to do. For example, in FIG. 2, the second urging means 53 is a compression spring, one end of the second urging means 53 is supported by the inner wall in the second flow path 27, and the other end is the valve body locking member 50. However, any configuration may be used as long as the engaging portion 52 is urged so as to move in a predetermined direction.

  In the check valve 20 shown in FIGS. 2 and 3, the pressure receiving portion 51 has a pressure receiving surface 55 (the pressure receiving surface 55 is usually arranged in parallel with the transverse section of the second flow path 27). 2 (a), the check valve 20 is disposed so as to be positioned in the longitudinal section, and the inner diameter of the through hole 36 is set larger than the outer diameter of the locking portion 52, and the locking portion 52 is Between the locking position (FIG. 2B) and the locking release position (FIG. 3) of the valve body 41, it is possible to slide and move in the direction crossing the flow direction F of the liquid medium in the first flow path 22. However, it is only necessary to be able to move the locking portion 52 between the locking position of the valve body 41 and the unlocking position, and the present invention is not limited to sliding movement. 4A to 4C show the state when the locking portion 52 of the valve body locking member 50 is in the locking position of the valve body 41 (FIG. 2B). FIG. 4A is a conceptual diagram when seen from three directions so that the positional relationship between the first flow path 22, the second flow path 27, and the valve body 41 can be understood, and FIG. 4A is a plan perspective view, and FIG. Is a side perspective view and FIG. 4C is a rear perspective view.

  In the embodiment shown in FIGS. 2 to 4, the second flow path 27 has a mode in which three hollow portions 28, 29, and 30 are connected in a crank shape as shown in FIGS. 4 (a) to 4 (c). Show. That is, the first hollow portion 28 extends from the branch port 26 vertically upward with respect to the flow direction F of excess fuel, and the second hollow portion 29 extends from the first hollow portion 28 to the excess fuel. The third hollow portion 30 extends along the flow direction F, and extends in a direction perpendicular to the extending direction of the second hollow portion 29, and is formed at the bottom of the third hollow portion 30. A through hole 36 communicating with the first flow path 22 from the midway position, for example, an elongated through hole 36 formed so as to be long in the extending direction of the third hollow portion 30 is formed.

  The valve body locking member 50 locks the valve body 41 in the closed state to prevent abnormal movement of the valve body 41 due to pressure pulsation generated on the outlet 25 side of the check valve 20. When the check valve 20 of the present invention including the valve body locking member 50 having such a configuration is used in the embodiment shown in FIG. 1, for example, in the coasting state, the fuel injection device 16 does not inject fuel. In the case of the state, even if negative pressure suction due to pressure pulsation due to the plunger operation of the fuel pump 13 occurs in the second return line 18, the first return line 17 upstream of the check valve 20 The abnormal movement of the valve body 41 moving away from the valve seat 23 or swinging regardless of the hydraulic pressure can be suppressed, and malfunction of the check valve 20 can be prevented.

  Further, in the check valve 20 of the present invention, the valve body locking member 50 has the valve body 41 in the valve opening direction based on the hydraulic pressure of excess fuel existing on the upstream side of the valve seat 23 in the first flow path 22. Before the movement, the pressure receiving portion 51 is first pushed and moved by the action of the hydraulic pressure of excess fuel entering the second flow path 27, and the locking portion 52 is moved from the locking position of the valve body 41 to the locking release position. Is configured to move to. Based on the embodiment shown in FIG. 1, the hydraulic pressure of excess fuel in the first return pipe 17 on the upstream side of the check valve 20 exceeds the biasing force of the first compression biasing means 42, and the valve body 41. Before the valve member 23 moves away from the valve seat 23 in the valve opening direction, the valve body locking member 50 is moved by the pressure of the pressure receiving portion 51 by the excess fuel entering the second flow path 27 through the branch port 26. The valve body 41 is normally moved in accordance with the hydraulic pressure in the first return pipe 17 on the upstream side with respect to the check valve 20 because it is pressed and moved from the locking position with the body 41 to the unlocking position. There is no hindrance.

  The excess fuel hydraulic pressure in the first return pipe 17 upstream of the check valve 20 exceeds the urging force of the first compression urging means 42, and the valve body 41 moves away from the valve seat 23 in the valve opening direction. As a specific means for pressing the pressure receiving portion 51 by the excess fuel entering the second flow path 27 through the branch port 26 before moving, for example, the urging force of the second urging means 53 is used. The biasing force of the first biasing means 42 is preferably set smaller than the biasing force. The urging force of the second urging means 53 is set based on the hydraulic pressure that is desired to be maintained in the first return line 17 on the upstream side. For example, the first return line 17 on the upstream side with respect to the check valve 20 is set. When the back pressure is maintained at 0.3 to 0.8 bar, the second urging means 53 has a pressure of less than 0.3 bar, preferably 0.1 bar or less at the pressure receiving portion 51 of the valve body locking member 50. It is configured to compress and move when acted. Since the second urging means 53 compresses and moves before the first urging means 42 compresses and moves, when the valve body 41 of the check valve 20 moves normally from the closed state to the opened state, Since the valve body locking member 50 has already been moved to the unlocking position with the valve body 41, the valve body 41 is not obstructed from moving in the valve opening direction. In addition, when the valve body 41 moves from the open state to the valve closing direction, the first biasing means 42 and the second biasing means 53 are set to each other by appropriately setting the mutual biasing force relationship. Since the extension (restoration) movement of the biasing means 42 is configured to occur before the extension movement of the second biasing means 53, the valve body locking member 50 does not prevent the valve body 41 from being seated. Absent.

  The check valve 20 according to the present invention is arranged in the fuel return line for returning fuel from the fuel injection device 16 to the fuel tank 11, that is, the first return line 17, as in the embodiment shown in FIG. For example, abnormal movement of the valve body 41 due to negative pressure caused by pressure pulsation in the second return pipe 18 can be prevented.

  FIG. 5 is an exploded perspective view showing another embodiment of the check valve 20. The check valve 20 shown in FIG. 5 includes an inlet portion 33 and an outlet portion in which the valve casing 21 is attached to the casing main body 32 and both ends of the casing main body 32 in the flow direction F of the liquid medium. 34, and the low-pressure excess fuel returning from the fuel injection device 16 to the fuel tank 11 flows through the inside of the casing main body portion 32 located between the inlet portion 33 and the outlet portion 34. One flow path 22 extends. The casing body 32 is liquid-tightly closed by the lid 35 after the valve body locking member 50 is disposed in the second flow path 27. The casing main body 32 can preferably integrally form the lid 35 by welding.

  Further, FIG. 6 shows another embodiment of the check valve 20, and particularly shows an example of specific means for forming the second flow path 27. The second flow path 27, particularly the second hollow portion 29 and the third hollow portion 30 are formed by cutting from above the casing body 32, and the first hollow portion 28 is perforated until it penetrates the first flow path 22. Formed. The through hole 36 is formed by drilling from a predetermined position at the bottom of the third hollow portion 30 to a predetermined position downstream of the valve seat 23 of the first flow path 22.

  Furthermore, the second flow path 27 can be formed in the casing main body 32 together with the first flow path 22 by casting, injection molding or the like using a mold, a core or the like.

  FIG. 7 shows a conventionally known check valve 200. In this known check valve 200, negative pressure generated due to pressure pulsation in the second return pipe on the downstream side of the check valve 200 may act on the valve body 410. There was room for improvement in terms of maintaining the valve closed state. For example, when the total pressure of the negative pressure and the back pressure existing on the upstream side of the check valve 200 exceeds the urging force of the compression spring 420 that presses the valve body 410 against the valve seat 230 to form a valve closing state, The body 410 may leave the valve seat 230 and open unintentionally. On the other hand, the check valve 20 according to the present invention achieves the above improvement by including the valve body locking member 50. The above description only shows an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

  According to the present invention, by providing an appropriate valve body locking member that locks the valve body in the valve-closed state, abnormal movement of the valve body due to pressure pulsation generated on the outlet side of the check valve is prevented. It is now possible to provide a check valve that can do this.

DESCRIPTION OF SYMBOLS 10 Common rail type fuel injection system 11 Fuel tank 12 Fuel filter 13 Fuel pump 14 Pressure control valve 15 Common rail 16 Fuel injection device 17 1st return line 18 2nd return line 19 3rd return line 20 Check valve 21 Valve casing 22 First flow path 23 Valve seat 24 Inlet 25 Outlet 26 Branch port 27 Second flow path 28 First hollow portion 29 Second hollow portion 30 Third hollow portion 32 Valve casing main body 33 Inlet portion 34 Outlet portion 35 Lid 36 Through-hole 40 Valve mechanism 41 Valve body (or sphere)
42 1st biasing means (or compression spring)
50 Valve body locking member 51 Pressure receiving portion 52 Locking portion 53 Second urging means (or compression spring)
54 Longitudinal extending portion 55 Pressure receiving surface

Claims (5)

A valve casing formed inside with a first flow path through which a liquid medium flows and a valve seat;
A valve body located in the valve casing and movable across the open / close position of the valve in accordance with the liquid pressure of the liquid medium, and a direction against the direction in which the liquid medium flows through the valve body, and A valve mechanism having first biasing means for biasing in the valve closing direction to be seated on the valve seat and to be in a closed state;
And when the fluid pressure of the liquid medium existing on the upstream side of the valve seat exceeds the urging force of the first urging means when viewed in the flow direction of the liquid medium, the valve body is A check valve that moves away from the valve seat and opens.
A second flow path having a branch port branched from the first flow path is formed at a position of the first flow path between the check valve inlet and the valve seat;
A pressure receiving portion located in the second flow path for blocking the flow of the liquid medium entering the second flow path, and movably disposed in the first flow path; A valve body locking member that has a locking portion that is integral with the pressure receiving portion, and moves to a position that contacts the valve body to lock the valve body;
To bias the valve body locking member so that the locking section moves in a direction that resists the fluid pressure of the liquid medium acting on the pressure receiving section and that locks the valve body. Second biasing means,
With
The valve body locking member locks the valve body in the closed state to prevent abnormal movement of the valve body due to pressure pulsation generated on the outlet side of the check valve, and the first The liquid pressure of the liquid medium that enters the second flow path before the valve body moves in the valve opening direction based on the liquid pressure of the liquid medium existing on the upstream side of the valve seat in the flow path. The check valve is configured such that the pressure receiving portion is first pressed and moved by the action of the above, so that the locking portion moves from the locking position of the valve body to the locking release position.   2. The check valve according to claim 1, wherein a biasing force of the second biasing unit is smaller than a biasing force of the first biasing unit.   The movement of the locking portion between the locking position and the locking release position of the valve body is a sliding movement in a direction crossing the flow direction of the liquid medium in the first flow path. The check valve according to claim 1 or 2.   4. The check valve according to claim 1, wherein the check valve is disposed in a fuel return line for returning fuel from the fuel injection device to the fuel tank. 5. The valve body is a sphere,
The check valve according to any one of claims 1 to 4, wherein each of the first urging means and the second urging means is a compression spring.

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