JP4518004B2 - Regulating valve - Google Patents

Description

  The present invention relates to a regulating valve that regulates a fluid pressure to a predetermined pressure, and relates to a technique suitable for use in, for example, a supply pump of a common rail fuel injection device.

(Conventional technology)
As an example of a prior art of a regulating valve that regulates fluid pressure to a predetermined pressure, a regulating valve mounted on a supply pump used in a common rail fuel injection device is known (see, for example, Patent Document 1).
A schematic configuration of the supply pump is shown in FIG. The supply pump 3 includes a feed pump 14, a regulating valve 15, an electromagnetic metering valve (hereinafter referred to as SCV) 16, a high-pressure pump 17, and the like.

The feed pump 14 sucks the fuel in the fuel tank and pumps the sucked fuel to the high-pressure pump 17.
The regulating valve 15 includes a valve housing 44 having a fluid inlet 41 and a fluid outlet 42, a valve body 45 supported so as to be movable in the valve housing 44, and the valve body 45 attached in the closing direction of the fluid inlet 41. A return spring 46 for energizing, and the degree of communication between the fluid inlet 41 and the fluid outlet 42 increases as the fluid pressure applied to the fluid inlet 41 (fuel pressure on the discharge side of the feed pump 14) increases. By increasing the amount of returning a part of the fuel on the discharge side to the low pressure side, the pressure on the discharge side of the feed pump 14 (hereinafter referred to as feed pressure) is maintained at a predetermined pressure.

(Problems of conventional technology)
The supply pump 3 mounted on the vehicle has an “abnormal condition” such as clogging of the fuel filter, throttling in the fuel pipe, or the like, resulting in a high load of fuel discharge or air mixing into the fuel. there is a possibility.
If the vehicle continues to run under such an “abnormal condition”, the pulsation of the feed pressure may occur and the SCV 16 may be damaged or the SCV 16 may be unplugged. If the SCV 16 is broken or the SCV 16 is unplugged, there is a possibility that the vehicle will be greatly damaged.
JP 2002-250459 A

  The present invention has been made in view of the above-described problems, and the purpose of the present invention is to intentionally break the regulator valve when the fluid pressure (for example, feed pressure) on the fluid inlet side becomes abnormally high. Accordingly, there is provided a regulating valve that can forcibly reduce the pressure on the fluid inlet side and prevent the occurrence of large damage.

[Means of claim 1]
The valve body of the regulating valve that employs the means of claim 1 includes a through hole that communicates the fluid inlet side and the spring chamber, and a safety plug that is locked to the valve body and closes the through hole. When the fluid pressure applied to the fluid inlet exceeds the specified pressure, the locking is broken (that is, the locking is released ), and the safety plug is detached from the valve body so that the valve always communicates. And communicate with each other through the through hole and the spring chamber.
Thus, when the fluid pressure applied to the fluid inlet becomes equal to or higher than the specified pressure, the regulator valve is deliberately broken (i.e., locking is disengaged) by the fluid inlet fluid inlet and breathing port to communicate at all times The pressure on the side drops forcibly. That is, the fluid pressure adjusted by the regulating valve is forcibly reduced.
As a result, it is possible to avoid the occurrence of large damage caused by the fluid pressure adjusted by the regulating valve becoming an abnormal pressure.
In addition, the fluid inlet and the breathing port communicate with each other through the through hole and the spring chamber just by removing the safety plug from the valve body in the valve housing, so that fluid leaks to the outside from the regulated valve that is intentionally damaged. There is no.
Furthermore, even if the regulated valve is intentionally damaged, the repair can be completed only by exchanging the valve body to which the safety plug is locked, and the cost required for the repair can be suppressed.

[Means of claim 2]
A closing member is provided outside the regulating valve employing the means of claim 2 to prevent the fluid flowing out from the spring chamber in which the return spring is disposed from leaking to the outside when the spring seat plug is damaged. When the fluid pressure applied to the fluid inlet becomes equal to or higher than the specified pressure, the spring seat plug is broken and the compression of the return spring is released.
As described above, when the fluid pressure applied to the fluid inlet becomes equal to or higher than the specified pressure, the regulating valve is intentionally damaged (that is, the spring seat plug is damaged). As a result, the valve body is displaced in the fully open direction by the pressure applied from the fluid inlet, and the degree of communication between the fluid inlet and the fluid outlet is maximized , so that the fluid flows out to the fluid outlet without leaking outside. Drops forcibly. That is, the fluid pressure adjusted by the regulating valve is forcibly reduced.
As a result, it is possible to avoid the occurrence of large damage caused by the fluid pressure adjusted by the regulating valve becoming an abnormal pressure.
Even if the spring seat plug is damaged, the blocking member prevents the fluid from flowing out of the spring chamber, so that the fluid does not leak to the outside from the regulated valve that is intentionally damaged.
Furthermore, even if the regulated valve is intentionally damaged, the repair can be completed simply by replacing the spring seat plug, and the cost required for the repair can be suppressed.

[Means of claim 3]
The return spring of the regulating valve employing the means of claim 3 is a compression coil spring. When the fluid pressure applied to the fluid inlet becomes equal to or higher than the specified pressure, the fluid pressure applied to the fluid inlet is transmitted to the spring seat plug via the valve body and the compression coil spring, and the spring seat plug is damaged.

[Means of claim 4]
The regulating valve adopting the means of claim 4 is mounted on a supply pump, and the supply pump supplies a high-pressure fuel to a common rail for accumulating high-pressure fuel, and supplies fuel from the fuel tank to the high-pressure pump. A feed pump , the fluid inlet is connected to the discharge side of the feed pump, and the fluid outlet is connected to the low pressure side of the feed pump to regulate the discharge pressure of the feed pump.
The common rail fuel injection system is operated under “abnormal conditions” such as when the fuel filter is clogged, the fuel pipe is throttled, etc., resulting in a high load of fuel discharge or when air is mixed into the fuel. When pulsation occurs in the pressure and the fluid pressure applied to the fluid inlet exceeds the specified pressure, the regulating valve is intentionally broken ( ie, the safety plug is locked or the spring seat plug is broken). The fluid pressure at which the valve regulates is forcibly reduced.
As a result, the discharge pressure of the feed pump cannot be increased, the increase in engine output is suppressed, and the engine is stopped, so that problems such as the SCV being broken can be avoided, and the vehicle is greatly damaged. It can be avoided.

After the engine is stopped, fuel is not sent from the feed pump to the high-pressure pump, so the engine does not restart. This makes it possible to find an “abnormal condition” without damaging the vehicle.
Further, fuel does not leak to the outside from the regulating valve.
Furthermore, even if the regulated valve is intentionally damaged, the repair can be completed simply by replacing the “valve element with the safety plug locked” or the “spring seat plug”. It can be kept low.

The regulating valve of the best mode 1 adjusts the degree of communication between the fluid inlet and the fluid outlet by the movement of the valve body, and a spring chamber in which a return spring that biases the valve body in the valve closing direction is disposed via the breathing port. Communicate with the low pressure side.
The valve body includes a through-hole communicating with the fluid inlet side and the spring chamber, and also includes a safety plug that is locked to the valve body and closes the through-hole, and when the fluid pressure applied to the fluid inlet exceeds a specified pressure. Then, the lock is released and the safety plug is detached from the valve body, and the fluid inlet and the breathing port communicate with each other through the through hole and the spring chamber.

In the regulating valve of the best mode 2, the degree of communication between the fluid inlet and the fluid outlet is adjusted by the movement of the valve body, and a return spring that biases the valve body in the valve closing direction is compressed by the spring seat plug.
A blocking member is provided outside the regulating valve to prevent the fluid flowing out from the spring seat plug from leaking to the outside when the spring seat plug is damaged, and when the fluid pressure applied to the fluid inlet exceeds a specified pressure. The spring seat plug is broken, releasing the compression of the return spring.

  A first embodiment in which the present invention is applied to a regulator valve of a supply pump in a common rail fuel injection device will be described with reference to the drawings. In the first embodiment, the “common rail fuel injection device” will be described first with reference to FIGS. 3 and 4, and then the “characteristics of the first embodiment” will be described with reference to FIGS. 1 and 2. .

[Description of common rail fuel injection system]
The common rail fuel injection device shown in FIG. 3 is a system that injects fuel into each cylinder of an engine (for example, a diesel engine: not shown), and includes a common rail 1, an injector 2, a supply pump 3, an ECU 4 (engine control unit), and an EDU 5 (Drive unit). The EDU 5 may be built in the case of the ECU 4.

  The common rail 1 is a pressure accumulating container that accumulates high-pressure fuel supplied to the injector 2, and discharges from the supply pump 3 that pumps high-pressure fuel through the high-pressure pump pipe 6 so that the common rail pressure corresponding to the fuel injection pressure is accumulated. In addition to being connected to the outlet, a plurality of injector pipes 7 for supplying high pressure fuel to each injector 2 are connected.

A pressure limiter 10 is attached to a relief pipe 9 that returns fuel (light oil or the like: an example of liquid) from the common rail 1 to the fuel tank 8. The pressure limiter 10 is a pressure safety valve, and is opened when the common rail pressure exceeds the limit set pressure, and suppresses the common rail pressure below the limit set pressure.
A pressure reducing valve 11 is attached to the common rail 1. The pressure reducing valve 11 is opened by a valve opening instruction signal given from the ECU 4 and rapidly reduces the common rail pressure via the relief pipe 9. Thus, by mounting the pressure reducing valve 11 on the common rail 1, the ECU 4 can quickly control the common rail pressure to a pressure corresponding to the vehicle running state. There are some models in which the pressure reducing valve 11 is not provided.

  The injector 2 is mounted in each cylinder of the engine and supplies fuel to each cylinder by injection. The injector 2 is connected to the downstream ends of a plurality of injector pipes 7 branched from the common rail 1 and accumulated in the common rail 1. A fuel injection nozzle that injects high-pressure fuel into each cylinder, and an electromagnetic valve that performs lift control of a needle accommodated in the fuel injection nozzle are mounted. The leaked fuel from the injector 2 is also returned to the fuel tank 8 through the relief pipe 9.

  The supply pump 3 is a high-pressure fuel pump that sucks the fuel in the fuel tank 8 through a fuel filter 13 provided in the middle of the fuel suction pipe 12 and feeds the sucked fuel to a high pressure by feeding it to the common rail 1. As shown in FIG. 4, the feed pump 14, the regulating valve 15, the SCV 16, and two high-pressure pumps 17 in this embodiment are configured. The configuration of the supply pump 3 will be described later.

The ECU 4 is equipped with a CPU and a storage device (ROM, RAM, SRAM, EEPROM, etc.), a program stored in the ROM, and signals of the sensors (vehicle driving state) read into the RAM. Various arithmetic processes are performed based on the above.
An example of a specific calculation is as follows. For each fuel injection, the ECU 4 determines each cylinder based on a program stored in the ROM and a sensor signal (vehicle operating state) read into the RAM. The target injection amount, the injection mode, the valve opening timing of the injector 2, and the opening (energization current value) of the SCV 16 are provided.

The EDU 5 includes an injector drive circuit. This injector drive circuit is a drive circuit that provides a valve opening drive current to the solenoid valve of the injector 2 based on an injector valve opening signal given from the ECU 4, and the high pressure fuel is supplied into the cylinder by supplying the valve opening drive current to the solenoid valve. The fuel injection is stopped by stopping the valve opening drive current. Here, FIG. 3 shows an example in which the SCV drive circuit for supplying a drive current to the solenoid valve of the SCV 16 is arranged in the case of the ECU 4, but it may be arranged in the case of the EDU 5.
In addition to the pressure sensor 18 that detects the common rail pressure, the ECU 4 includes an accelerator sensor that detects the accelerator opening, an engine speed sensor that detects the engine speed, Sensors such as a water temperature sensor for detecting the cooling water temperature are connected.

(Description of supply pump 3)
The supply pump 3 will be described with reference to FIG .
As described above, the supply pump 3 includes the feed pump 14, the regulating valve 15, the SCV 16, and two high-pressure pumps 17 in this embodiment.
The feed pump 14 is a low-pressure supply pump that sends the fuel sucked from the fuel tank 8 to the two high-pressure pumps 17 via the SCV 16, and is configured by, for example, a trochoid pump that is rotationally driven by a camshaft 19.
The camshaft 19 is a pump drive shaft and is rotationally driven by the crankshaft of the engine.

The regulating valve 15 is disposed in the middle of the fuel passage 20 that communicates the discharge side and the low pressure side of the feed pump 14, opens according to the discharge pressure of the feed pump 14, and fuel on the discharge side of the feed pump 14. The pressure on the discharge side of the feed pump 14 is adjusted to a predetermined pressure (feed pressure) by returning a part of the pressure to the low pressure side of the feed pump 14. Details of the regulating valve 15 will be described later.
Of the fuel passage 20, a passage for leading a part of the fuel discharged from the feed pump 14 to the regulation valve 15 is an introduction passage 21, and a passage for guiding the exhaust fuel discharged by the regulation valve 15 to the low pressure side of the feed pump 14. This is a discharge passage 22.

The SCV 16 is disposed in the middle of the fuel passage 31 that guides fuel from the feed pump 14 to the high-pressure pump 17, and adjusts the amount of fuel sucked into the pressurizing chamber (plunger chamber) 32 of the high-pressure pump 17. The pressure is changed and adjusted.
The SCV 16 is a valve that adjusts the amount of fuel sucked into the pressurizing chamber 32 and changes the amount of fuel discharged to the common rail 1 by being controlled by a pump drive signal from the ECU 4. The common rail pressure is adjusted by adjusting the discharge amount of fuel pumped to the common rail 1.

The two high-pressure pumps 17 are plunger pumps that repeatedly suck and compress fuel, and compress the fuel supplied from the SCV 16 to a high pressure and supply it to the common rail 1. The two high-pressure pumps 17 repeat the intake and compression of fuel at different periods with a phase difference of 180 degrees. In some cases, three or more high-pressure pumps 17 are provided.
Each high-pressure pump 17 includes a plunger 33 that is reciprocated by a common camshaft 19, a suction valve (check valve) 34 that supplies fuel to a pressurizing chamber 32 whose volume changes due to the reciprocating movement of the plunger 33, A discharge valve (check valve) 35 that discharges the fuel compressed in the pressure chamber 32 toward the common rail 1 is provided.

The plunger 33 is pressed against a cam ring 37 mounted around the eccentric cam 36 of the camshaft 19 by a spring 38. When the camshaft 19 rotates, the plunger 33 reciprocates with the eccentric operation of the cam ring 37.
When the plunger 33 is lowered and the pressure in the pressurizing chamber 32 is lowered, the discharge valve 35 is closed and the intake valve 34 is opened to supply the fuel adjusted by the SCV 16 into the pressurizing chamber 32. . Conversely, when the plunger 33 rises and the pressure in the pressurizing chamber 32 rises, the suction valve 34 closes. When the pressure pressurized in the pressurizing chamber 32 reaches a predetermined pressure, the discharge valve 35 is opened, and the high-pressure fuel pressurized in the pressurizing chamber 32 is discharged toward the common rail 1.

[Features of Example 1]
In the feature of the first embodiment, the “regular valve 15 having the conventional configuration” will be described first with reference to FIG. 2, and then the “regulator valve 15 to which the present invention is applied” will be described with reference to FIG. 1. To do.

(Description of the conventional regulating valve 15)
The regulating valve 15 includes a valve housing 44 having a fluid inlet 41, a fluid outlet 42 and a breathing port 43, a valve body 45 movably supported in the valve housing 44, and closing the valve body 45 with respect to the fluid inlet 41. The return spring 46 is urged in the direction.

  The valve housing 44 has a substantially cylindrical shape with a male screw formed on the outer peripheral surface, and a valve stopper 47 is mounted in a cylinder at the tip (lower side in FIG. 2) of the valve housing 44. A fluid inlet 41 that connects the introduction passage 21 and the valve housing 44 is formed at the center of the valve stopper 47. A pressure regulating chamber 48 is formed in a space surrounded by the valve stopper 47 and the valve body 45 in the valve housing 44. The valve housing 44 is assembled to the supply pump 3 so that the side on which the valve stopper 47 is mounted communicates with the introduction passage 21, and fuel guided from the introduction passage 21 (discharged fuel of the feed pump 14) is fluid. It flows into the pressure regulating chamber 48 through the inlet 41.

A fluid outlet 42 and a breathing port 43 communicating with the discharge passage 22 are formed on the side surface of the valve housing 44.
The opening of the fluid outlet 42 is adjusted by a valve body 45 that slides in the valve housing 44 by the pressure in the pressure regulating chamber 48. When the pressure in the pressure regulating chamber 48 is low, the biasing force of the return spring 46 is overcome. As the fluid outlet 42 is closed by the valve body 45 and the pressure in the pressure regulating chamber 48 increases, the valve body 45 is biased toward the return spring 46 by the pressure in the pressure regulating chamber 48, and the opening ratio of the fluid outlet 42 is increased. Rise.
On the other hand, the breathing port 43 is a breathing hole that communicates the spring chamber 49 in which the return spring 46 is disposed and the discharge passage 22.

The valve body 45 is disposed in the valve housing 44 through a minute clearance and is supported so as to be slidable in the axial direction within the valve housing 44. As described above, the pressure and return of the pressure regulating chamber 48 are returned. The fluid outlet 42 is opened and closed in accordance with the balance with the spring 46.
The return spring 46 is a compression coil spring disposed in the spring chamber 49, and is compressed between the valve seat 45 and the spring seat plug 51 fixed to the rear end (upper side in FIG. 2) of the valve housing 44. The valve body 45 is urged in a direction in which the volume of the pressure regulating chamber 48 is reduced.

(Background of Example 1)
The supply pump 3 may cause an “abnormal condition” such as a fuel discharge pressure becoming a heavy load or air being mixed into the fuel due to clogging of the fuel filter, throttling in the fuel pipe, or the like.
If the vehicle continues to run under such “abnormal conditions”, pulsation of the feed pressure may occur, and the SCV 16 shown in FIG. 4 may be damaged or the SCV 16 may be unplugged.
Specifically, when the pulsation of the feed pressure occurs, the valve 16a of the SCV 16 may pulsate greatly, and the spring 16b of the SCV 16 may be damaged. If the spring 16b of the SCV 16 is damaged, the opening degree of the SCV 16 cannot be controlled, and there is a concern that the common rail pressure may abnormally increase. Further, the fuel pressure applied to the SCV 16 abnormally rises due to pulsation, the SCV 16 is damaged, and there is a concern that fuel leakage may occur from the supply pump 3 due to the components of the SCV 16 coming out of the supply pump 3.

(Description of Regulating Valve 15 to which the Present Invention is Applied)
In order to solve the above problems, the regulator valve 15 mounted on the supply pump 3 of the first embodiment employs the following configuration.
As shown in FIG. 1A, the valve body 45 of the regulating valve 15 of the first embodiment has a through hole 52 that communicates the fluid inlet 41 side (that is, the pressure regulating chamber 48) and the spring chamber 49. Is provided.
Further, a safety plug 53 that closes the through hole 52 is engaged with the valve body 45.

A locking technique for the safety plug 53 in the first embodiment will be described.
A concave portion 54 that opens to the spring chamber 49 side is formed on the spring chamber 49 side of the valve body 45 made of a metal material. The recess 54 is, for example, a round hole, and the through hole 52 is opened at the bottom.
On the other hand, the safety plug 53 made of a metal material is, for example, a substantially cylindrical body that is press-fitted into the recess 54 from the opening side of the recess 54, and the safety plug 53 is press-fitted into the recess 54, thereby adjusting the through hole 52. The communication between the pressure chamber 48 and the spring chamber 49 is blocked.

  When the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than a specified pressure (a pressure lower than a pressure at which a malfunction occurs in the supply pump 3 by a predetermined value), the force applied from the through hole 52 to the safety plug 53 is shown in FIG. As shown in b), the safety plug 53 is designed so that the press-fit (corresponding to locking) is released and the safety plug 53 comes out of the recess 54. That is, when the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than the specified pressure due to the pulsation of the feed pressure, the safety plug 53 is detached from the valve body 45, and the fluid inlet 41 and the breathing port 43 are connected to the spring chamber 49. And it communicates through the through hole 52. Here, each passage area of the through hole 52 and the breathing port 43 is set to a passage area that does not increase the discharge pressure of the feed pump 14 in a state where the safety plug 53 is detached from the valve body 45.

The regulation valve 15 of the first embodiment employs the above-described configuration, so that the fuel discharge pressure becomes a heavy load or air is mixed into the fuel due to clogging of the fuel filter, restriction in the fuel pipe, or the like. When the common rail fuel injection device is operated under “abnormal conditions” such as when the feed pressure pulsates and the fuel pressure applied to the fluid inlet 41 exceeds the specified pressure, the engagement with the valve body 45 is broken ( That is, the safety plug 53 is detached from the valve body 45 so as to always communicate with each other by releasing the locking by press-fitting. That is, the regulating valve 15 is intentionally damaged.
As a result, the introduction passage 21 and the discharge passage 22 are always in communication with each other through the fluid inlet 41 → pressure regulating chamber 48 → through hole 52 → spring chamber 49 → breathing port 43, and the discharge pressure of the feed pump 14 increases. Disappear. As a result, fuel cannot be pumped to the common rail 1. For this reason, the engine output is reduced, the engine operation is stopped, and problems such as damage to the SCV 16 can be avoided. That is, it is possible to avoid the occurrence of great damage to the vehicle.

After the engine is stopped, the fuel is not sent from the feed pump 14 to the high-pressure pump 17, so the engine does not restart. This makes it possible to find an “abnormal condition” without damaging the vehicle.
Further, since the safety plug 53 is simply detached from the valve body 45 in the valve housing 44, fuel does not leak to the outside from the regulated valve 15 that is intentionally damaged.
Furthermore, even if the regulating valve 15 is intentionally damaged, the repair can be completed simply by replacing the valve body 45 to which the safety plug 53 is locked, and the repair cost of the supply pump 3 can be kept low. it can.

A second embodiment will be described with reference to FIG. In the following embodiments, the same reference numerals as those in Embodiment 1 denote the same functional objects.
In the first embodiment, the example in which the safety plug 53 is locked to the valve body 45 by press-fitting the safety plug 53 into the recess 54 of the valve body 45 is shown.
On the other hand, in the second embodiment, the safety plug 53 is inserted into the recess 54 of the valve body 45 and the joint portion between the valve body 45 and the safety plug 53 is crimped, so that the safety plug 53 is attached to the valve body 45. It locks.

Specifically, in the second embodiment, a minute clearance is provided between the inner diameter of the recess 54 and the outer diameter of the safety plug 53, and the safety plug 53 is inserted into the recess 54 so that the bottom of the recess 54 is inserted. The safety plug 53 is locked to the valve body 45 by closing the through-hole 52 opened by the safety plug 53 and crimping the joint portion of the valve body 45 and the safety plug 53 at a plurality of positions in that state.
When the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than the specified pressure, the caulking 55 is disengaged by the force applied to the safety plug 53 from the through hole 52 (i.e., the engagement is broken), safety plug 53 is concave Designed to exit 54.
By adopting the configuration of the second embodiment, the same effect as that of the first embodiment can be obtained.

A third embodiment will be described with reference to FIG.
In order to solve the problem disclosed in “Background of Embodiment 1,” the regulated valve 15 of Embodiment 3 employs the following configuration.
The spring seat plug 51 of the third embodiment is provided in the spring chamber 49 in which the return spring 46 is disposed so as to compress the return spring 46, and when the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than a specified pressure. damaged, it will be releasing the compression of the return spring 46.
On the other hand, outside the regulating valve 15 (atmosphere side), when the spring seat plug 51 is damaged, fuel that flows out from the spring chamber 49 in which the return spring 46 is disposed through the spring seat plug 51 is externally provided. A blocking member 56 is provided to prevent leakage.

A specific regulating valve 15 of Example 3 will be described.
A clearance is provided between the inner diameter of the insertion hole 58 of the regulating valve 15 formed in the pump housing 57 of the supply pump 3 and the outer diameter of the valve housing 44 of the regulating valve 15. Is movably provided in the insertion hole 58 in the axial direction (left-right direction in FIG. 6).
A second return spring 61 made of a coil spring is disposed between the valve housing 44 and the closing member 56 in a compressed state, and a valve stopper 47 provided at the tip of the valve housing 44 has a ring shape. It is pressed against the bottom of the insertion hole 58 via the seal member 62.

  The closing member 56 is a screw plug fastened to the pump housing 57. A female screw for fastening the closing member 56 is formed on the opening side of the insertion hole 58 in the pump housing 57, and a second seal member 63 having a ring shape is formed between the closing member 56 and the pump housing 57. As a result, the second return spring 61 is compressed between the valve housing 44 and the closing member 56 and the fuel in the closing member 56 does not leak to the outside. Sealed.

  The spring seat plug 51 is made of a metal material or a hard resin material, and when the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than a specified pressure, the spring seat plug 51 is connected to the spring seat via the valve body 45 and the return spring 46 in which the coil is in close contact with the axial direction. The spring seat plug 51 is designed to be damaged by the force applied to the plug 51. When the spring seat plug 51 is damaged, the compression of the return spring 46 is released. The spring seat plug 51 is provided with a material and a thickness so as to be damaged when the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than a specified pressure, and is provided with a groove or the like that promotes damage. There may be.

(Operation and effect of Example 3)
During normal operation, the valve stopper 47 at the tip of the valve housing 44 is pressed against the bottom of the insertion hole 58 through the seal member 62 by the biasing force of the second return spring 61 as shown in FIG. ing. For this reason, the valve body 45 is displaced according to the fuel pressure applied to the fluid inlet 41, the degree of communication between the fluid inlet 41 and the fluid outlet 42 is adjusted, and the feed pressure is adjusted.

  When the discharge pressure of the feed pump 14 increases to a pressure near the upper limit of the normal use range, as shown in FIG. 6B, the pressure received by the regulating valve 15 from the discharge side of the feed pump 14 increases. 2 The valve housing 44 moves to the right in FIG. 6 against the urging force of the return spring 61. As described above, the tip of the valve housing 44 is separated from the bottom of the insertion hole 58, whereby the fuel supplied from the introduction passage 21 is guided to the discharge passage 22 through the clearance between the valve housing 44 and the insertion hole 58. That is, the valve body 45 is opened to lower the discharge pressure of the feed pump 14 and the discharge pressure of the feed pump 14 is lowered through the clearance between the valve housing 44 and the insertion hole 58.

Further, when the fuel pressure applied to the fluid inlet 41 exceeds a specified pressure, the spring seat plug 51 is damaged due to an increase in the load applied to the spring seat plug 51 via the valve body 45 and the return spring 46, and the return spring. 46 compression is released. As a result, since the force biased in the valve closing direction is lost, the valve body 45 is displaced in the valve opening direction by the pressure applied to the pressure regulating chamber 48, and the fluid outlet 42 is fully opened, and the feed pump The discharge pressure of 14 does not increase. Here, the passage area of the fluid outlet 42 is set to a passage area that does not increase the discharge pressure of the feed pump 14 when the fluid outlet 42 is fully open.
As described above, when the fuel pressure applied to the fluid inlet 41 becomes equal to or higher than the specified pressure, the fuel pumping to the common rail 1 is stopped as in the first embodiment, the engine output is reduced, and the engine operation is reduced. Stops. As a result, it is possible to avoid problems such as breakage of the SCV 16, and it is possible to avoid large damage to the vehicle.

After the engine is stopped, the fuel is not sent from the feed pump 14 to the high-pressure pump 17, so the engine does not restart. This makes it possible to find an “abnormal condition” without damaging the vehicle.
Even if the spring seat plug 51 is damaged, the closing member 56 prevents the fuel from flowing out, so that the fuel does not leak to the outside from the regulated valve 15 that is intentionally damaged.
Furthermore, even if the regulating valve 15 is intentionally damaged, the repair can be completed simply by replacing the spring seat plug 51, and the cost required for the repair can be suppressed.

[Modification]
In the above-described embodiment, an example in which the present invention is applied to the regulating valve 15 mounted on the supply pump 3 of the common rail fuel injection device has been described. However, the present invention is applied to all the regulating valves 15 that regulate the fluid pressure. Can be applied.

(Example 1) which is sectional drawing of a regulating valve. It is sectional drawing of a regulating valve (prior art). It is a schematic diagram of a common rail type fuel injection device. It is sectional drawing of a supply pump. (Example 2) which is sectional drawing of a regulating valve. (Example 3) which is sectional drawing of a regulating valve. It is a schematic block diagram of a supply pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Common rail 3 Supply pump 8 Fuel tank 14 Feed pump 15 Regulating valve 17 High pressure pump 41 Fluid inlet 42 Fluid outlet 43 Breathing port 44 Valve housing 45 Valve body 46 Return spring 51 Spring seat plug 52 Through hole 53 Safety plug 56 Closure member

Claims (4)

A regulating valve in which the degree of communication between the fluid inlet and the fluid outlet is adjusted by movement of the valve body, and a spring chamber in which a return spring for biasing the valve body in the valve closing direction is arranged communicates with the low pressure side through the breathing port In
The valve body includes a through hole that communicates the fluid inlet side and the spring chamber, and includes a safety plug that is locked to the valve body and closes the through hole,
When the fluid pressure applied to the fluid inlet becomes equal to or higher than a specified pressure, the safety plug is detached from the valve body so that the locking is broken and always communicates , and the fluid inlet and the breathing port penetrate the penetrating hole. A regulating valve characterized by communicating through a hole and the spring chamber. A spring seat plug that compresses the return spring is provided in a spring chamber in which a return spring that adjusts the degree of communication between the fluid inlet and the fluid outlet by moving the valve body and biases the valve body in the valve closing direction is disposed. In the regulating valve,
A blocking member is provided outside the regulating valve to prevent the fluid flowing out of the spring chamber from leaking to the outside when the spring seat plug is damaged,
When the fluid pressure applied to the fluid inlet becomes equal to or higher than a specified pressure, the spring seat plug is broken, and the compression of the return spring is released, so that the valve body moves and the fluid inlet, the fluid outlet, Regulating valve characterized by the communication . The regulated valve according to claim 2,
The return spring is a compression coil spring,
When the fluid pressure applied to the fluid inlet becomes a specified pressure or more, the fluid pressure applied to the fluid inlet is transmitted to the spring seat plug via the valve body and the compression coil spring, and the spring seat plug is Regulating valve characterized by breakage. In the regulated valve in any one of Claims 1-3,
This regulated valve
Be one that is mounted on the supply pump in a common rail type fuel injection device, the supply pump is a high pressure pump for supplying high pressure fuel to the common rail for accumulating high-pressure fuel feed pump for supplying fuel in the fuel tank to the high pressure pump It equipped with a door,
The regulator valve characterized in that the fluid inlet is connected to the discharge side of the feed pump and the fluid outlet is connected to the low pressure side of the feed pump to regulate the discharge pressure of the feed pump.

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