JP2007205263A - Electromagnetic actuator for fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve wear resistance in an abutting part of the abutting surface 66 of an armature 7 and the restraining surface 72 of a stopper 9. <P>SOLUTION: In a solenoid valve 12, it is noted that a clearance is structurally provided without fail between the periphery of the cylindrical wall part 71 of the stopper 9 and the inner periphery of the fitting part 62 of a stator 14. A cylindrical clearance 75, an annular groove 76 and two or more passing holes 77 are used as fuel relief passages not to block a spring storage chamber 79 functioning as a fuel delivery passage when the armature 7 is pulled up by electromagnetic force of a solenoid valve 6 and the abutting surface 66 of the projection part 65 of the armature 7 abuts on the restraining surface 72 of the cylindrical wall part 71 of the stopper 9. Thereby, fuel passage grooves provided to the abutting surface 66 of the armature 7 or the restraining surface 72 of the stopper 9 are eliminated or reduced without deteriorating the operation stability of the armature 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic actuator for a fuel injection device having a stopper that restricts the full lift amount of an armature when the armature is attracted by electromagnetic force generated in an electromagnet, and in particular, performs fuel injection to a cylinder of an internal combustion engine. The present invention relates to an electromagnetic actuator for a fuel injection apparatus suitable for an injector solenoid valve for driving an injector.

[Conventional technology]
Conventionally, for example, fuel pumped up from a fuel tank is pressurized in a fuel injection pump to increase pressure, high pressure fuel discharged from the fuel injection pump is accumulated in a common rail, and a plurality of high pressure fuels accumulated in the common rail are stored. A fuel injection device that supplies fuel to each cylinder of an internal combustion engine via an injector is equipped with an electromagnetic actuator that opens (or closes) a valve by electromagnetic force generated in an electromagnet. As an electromagnetic actuator for this fuel injection device, there is a valve for driving a spool valve of an electromagnetic flow control valve (so-called fuel metering valve) assembled in a fuel injection pump, or a valve for an electromagnetic pressure reducing adjustment valve assembled in a common rail. One that drives, or one that controls the operation of the nozzle needle and command piston of an injector is known.

Here, an electromagnetic valve for an injector used as an electromagnetic actuator for the injector will be briefly described with reference to FIGS.
The operation of the injector solenoid valve 100 is performed by energizing the coil 13 to generate an electromotive force (electromagnetic force) in the electromagnet 101 including the coil 13 and the stator 14, and the magnetic force of the electromagnet 101 causes the magnetic pole surface of the stator 14. The armature 102 is pulled up to the side to open the valve 5 of the solenoid valve itself. As a result, fuel overflows from the pressure control chamber 37 provided in the injector body 31 to the fuel tank (low pressure side of the fuel system). Then, the fuel pressure acting in the direction in which the nozzle needle 32 is pressed against the sheet surface of the nozzle body 103 decreases, and the nozzle needle 32 opens the injection hole. Along with this, fuel injection into the combustion chamber of the cylinder of the internal combustion engine is started.

  When the energization of the coil 13 is stopped after a predetermined time has elapsed since the energization of the coil 13 of the injector solenoid valve 100 is started, the armature 102 is pushed down by the spring force of the coil spring 63, and the solenoid valve The own valve 5 is closed. As a result, the fuel is filled in the pressure control chamber 37 of the injector body 31, the fuel pressure acting in the direction of pressing the nozzle needle 32 against the nozzle body 103 increases, the nozzle needle 32 is pushed down, and the injection hole is closed. Along with this, fuel injection into the combustion chamber of the cylinder of the internal combustion engine is completed.

Here, the solenoid valve for injector 100 is a method of discharging the leaked fuel from the pressure control chamber 37 to the outside (low pressure side of the fuel system) when the valve 5 of the solenoid valve itself is opened. It is classified into one type.
As shown in FIG. 9 and FIG. 10, the top return is the leakage fuel that flows from the pressure control chamber 37 into the armature chamber 46 through the valve chamber 44 and the fuel discharge passage 45 when the valve 5 of the solenoid valve itself is opened. , Through a spring accommodating chamber 111 and a return passage (fuel discharge passage) 112 in a stopper 104 disposed in the center of the electromagnet 101, and from the leak port 113 opened at the upper end portion of the injector solenoid valve 100 to the outside (fuel system) The low pressure side). A return pipe is connected to the top return tube 114 in which the leak port 113 is formed via a union 115 and a pipe 116.
Further, as shown in FIG. 11, the side return is provided in the injector main body 31 with leaked fuel flowing from the pressure control chamber 37 through the valve chamber 44 and the armature chamber 46 when the valve 5 of the solenoid valve itself is opened. This is a method of discharging from the leak port 119 provided in the injector body 31 to the outside (low pressure side of the fuel system) through the return passage (fuel discharge passage) 117. A return pipe is connected to the pipe joint portion of the injector body 31 where the leak port 119 is formed via an outlet 120.

[Conventional technical problems]
However, the injector solenoid valve 100 of the top return type also serves as a fuel discharge passage when the armature 102 pulled up by the electromagnetic force of the electromagnet 101 abuts against the stopper 104 as shown in FIGS. A plurality of fuel escape grooves 121 are provided in the armature 102 or the stopper 104 so that the spring accommodating chamber 111 is not blocked, and a fuel passage 124 is provided between the electromagnet 101, the housing 122, and the stator case 123. The plurality of fuel escape grooves 121 have a groove width (α) of, for example, 0.8 mm and a groove depth of, for example, 0.5 mm.
Further, in the side return type injector solenoid valve 100, as shown in FIG. 14, the spring accommodating chamber 111 in the stopper 104 forms a bag hole by the housing 122 that holds and fixes the stopper 104, and the upper part of the coil 13. Since the fuel flowability of the armature 102 is poor, a fuel escape groove 125 is provided for allowing the fuel in the spring housing chamber 111 to escape when the armature 102 abuts against the stopper 104. Further, the electromagnet 101, the housing 122, and the retaining nut 126 A fuel passage 127 is provided therebetween.

  In addition, a shallow and thin groove 130 for preventing linking is provided on the end face of the armature 102 (the end face on the electromagnet side facing the magnetic pole face of the electromagnet 101). The inner surface of the annular contact face 131 is centered on the axis of the armature 102. It extends radially from the circumferential side. For this reason, the contact area between the contact surface 131 of the armature 102 and the regulating surface (contact surface) 132 of the stopper 104 is reduced, and the surface pressure at the contact surfaces 131 and 132 of both is increased. As a result, the amount of wear at the contact portion between the armature 102 and the stopper 104 increases, and there is a problem that the lift amount of the armature 102 changes.

  Therefore, for the purpose of preventing the lift amount of the armature from changing, a gap is provided between the inner periphery of the stator of the electromagnet and the outer periphery of the stopper, and a plurality of through holes that penetrate the cylindrical wall portion of the stopper are provided. When the valve of the solenoid valve itself is opened, leaked fuel (drain fuel) flowing from the valve chamber into the armature chamber is released to the space in the stopper through the gap and multiple through holes, and the fuel in the space in the stopper is backed up. There has been proposed an injector solenoid valve that allows a top return from a flow tube to the outside (see, for example, Patent Document 1).

  However, in the injector solenoid valve described in Patent Document 1, a gap is provided between the inner periphery of the stator and the outer periphery of the stopper by reducing the inner diameter of the stator of the electromagnet. As a result, the electromagnetic force of the electromagnet decreases, so that the coil diameter must be increased in order to be the same as the electromagnetic force of the electromagnet without gaps, and the outer diameter (physique) of the injector solenoid valve However, there was a problem that mountability deteriorated. Further, in the solenoid valve for an injector described in Patent Document 1, when the armature comes into contact with the stopper, a gap is defined with respect to the passage cross-sectional area of the fuel passage formed between the magnetic pole surface of the stator and the armature. The cross-sectional area of the passage is very large, which is also a factor for reducing the electromagnetic force of the electromagnet.

Therefore, a method of reducing the passage cross-sectional area of the gap to increase the magnetic pole area of the stator and suppressing the decrease in electromagnetic force of the electromagnet can be considered. However, in the electromagnetic valve for an injector described in Patent Document 1, the cylindrical wall portion of the stopper Since the plurality of through-holes are open on the opposite side of the armature side from the center in the axial direction, the passage length in the axial direction of the gap is long, and the leak fuel pressure when passing through the gap due to the orifice effect In addition, the time from the opening of the solenoid valve itself until the nozzle needle and the command piston start to lift (the valve opening delay time) becomes longer and the injector injection quantity characteristics The problem of changing.
Japanese Patent Laying-Open No. 2005-105923 (page 1-5, FIGS. 1-2)

  An object of the present invention is to provide an electromagnetic actuator for a fuel injection device that can improve wear resistance at a contact portion between an armature and a stopper. It is another object of the present invention to provide an electromagnetic actuator for a fuel injection device capable of suppressing a change in the lift amount of an armature while preventing a decrease in electromagnetic force of an electromagnet. In addition, the electromagnetic type for the fuel injection device can improve the wear resistance at the contact portion between the armature and the stopper while preventing the pressure and flow rate of the fuel passing through the gap between the electromagnet and the stopper from decreasing. It is to provide an actuator.

  According to the first aspect of the present invention, a gap is provided between the electromagnet and the stopper, an annular groove surrounding the outer periphery of the stopper side wall in the circumferential direction is provided, and the space on the inner peripheral side of the stopper side wall and the side wall of the stopper are provided. The through-hole which connects with the annular groove provided in the outer periphery of is provided. The through hole is communicated with the armature chamber through the annular groove and the gap. As a result, the flowability of the fuel flowing between the gap between the electromagnet and the stopper and the through hole can be improved, so that the gap between the electromagnet and the stopper is reduced to the minimum required passage cross-sectional area. be able to.

  Along with this, a gap can be formed between the electromagnet and the stopper without enlarging the inner diameter of the electromagnet, so that a decrease in electromagnetic force of the electromagnet can be suppressed. Therefore, it is not necessary to increase the outer diameter of the electromagnet in order to make it the same as the electromagnetic force of the electromagnet without a gap, and the size of the electromagnet (outer diameter) is increased, that is, the electromagnetic actuator for the fuel injection device Increase in size can be suppressed. As a result, it is possible to improve the mountability of the electromagnetic actuator for the fuel injection device.

  Here, in the case of top return, when the armature is attracted to the magnetic pole face side of the electromagnet by the electromagnetic force of the electromagnet, the fuel in the armature chamber (the fuel in the fuel passage formed between the magnetic pole face of the electromagnet and the armature) ) Flows through the gap between the electromagnet and the stopper, the annular groove and the through hole into the space on the inner peripheral side of the side wall of the stopper. Along with this, since the armature quickly comes into contact with the regulating surface of the stopper, a very fast operation response can be obtained.

  The fuel in the armature chamber (the fuel in the fuel passage formed between the magnetic pole face of the electromagnet and the armature) can be obtained without providing the fuel passage groove in the armature or the stopper or reducing the area of the fuel passage groove. Can flow in the space on the inner peripheral side of the side wall of the stopper, so that the contact area of the contact portion between the armature and the stopper can be increased (enlarged) without deteriorating the operational stability of the armature. . Along with this, the surface pressure of the contact portion between the armature and the stopper decreases, and the wear amount of the contact portion between the armature and the stopper decreases. Therefore, since the wear resistance of the contact portion between the armature and the stopper can be improved, it is possible to suppress the secular change of the lift amount of the armature.

  In the case of side return, when the armature is attracted to the magnetic pole surface side of the electromagnet by the electromagnetic force of the electromagnet, the fuel in the space on the inner peripheral side of the side wall of the stopper becomes the through hole, the annular groove, the electromagnet and the stopper. Flows out into the armature chamber (a fuel passage formed between the magnetic pole face of the electromagnet and the armature). Along with this, since the armature quickly comes into contact with the regulating surface of the stopper, a very fast operation response can be obtained.

  Even if the fuel passage groove is not provided in the armature or the stopper or the area of the fuel passage groove is reduced, the fuel in the space on the inner peripheral side of the side wall of the stopper is supplied to the armature chamber (the magnetic pole surface of the electromagnet and the armature). Therefore, the contact area of the contact portion between the armature and the stopper can be increased (enlarged) without deteriorating the operational stability of the armature. Along with this, the surface pressure of the contact portion between the armature and the stopper decreases, and the wear amount of the contact portion between the armature and the stopper decreases. Therefore, since the wear resistance of the contact portion between the armature and the stopper can be improved, it is possible to suppress the secular change of the lift amount of the armature.

According to the second aspect of the present invention, the annular groove provided on the outer periphery of the side wall of the stopper is changed from the outer peripheral surface of the side wall of the stopper to the side wall of the stopper so as to increase the passage sectional area of the gap between the electromagnet and the stopper. It is recessed toward the inner circumference side. Thereby, the clearance gap between an electromagnet and a stopper can be narrowed to the required minimum channel | path cross-sectional area.
According to the third aspect of the present invention, by making the groove depth of the annular groove provided on the outer periphery of the side wall of the stopper substantially the same as the passage length of the through hole, it is possible to suppress the strength reduction of the stopper. .

  According to the fourth aspect of the present invention, the stopper is provided with the side wall of the stopper that extends from the regulating surface to the opposite side in the axial direction from the armature side. Then, by arranging the through hole and the annular groove closer to the armature side than the central portion in the axial direction of the side wall of the stopper or in the vicinity of the regulating surface, the axial length of the gap between the electromagnet and the stopper is shortened. Become. Even if the gap between the electromagnet and the stopper is reduced to the minimum required passage cross-sectional area, the gap between the electromagnet and the stopper is short because the gap between the electromagnet and the stopper is short in the axial direction. It is difficult to reduce the pressure and flow rate of the passing fuel.

According to the fifth aspect of the present invention, A is the cross-sectional area of the fuel passage formed between the magnetic pole face of the electromagnet and the armature, B is the total area of the gap between the electromagnet and the stopper, and Assuming that the total area is C, the flowability of the fuel flowing between the space on the inner peripheral side of the stopper side wall and the fuel passage can be sufficiently secured by satisfying the relationship of A ≦ B and A ≦ C. The armature can perform a stable operation. Along with this, since the contact area of the contact portion between the armature and the stopper can be increased (enlarged), it becomes possible to improve the wear resistance of the contact portion between the armature and the stopper. Secular change of lift amount is suppressed.
According to the sixth aspect of the present invention, a plurality of penetrations penetrating the stopper side wall (in a direction substantially in a direction perpendicular to the axial direction of the stopper side wall (radial direction) radially) on the outer peripheral side of the stopper side wall. An annular groove is provided to connect all the holes. In this case, even if one through hole of the plurality of through holes is blocked by foreign matter or the like, or even if the remaining through hole is closed by foreign matter or the like while leaving one through hole, the fuel It is possible to suppress a decrease in flowability.

According to the seventh aspect of the invention, the armature is provided with radial grooves on the electromagnet side end surface including the abutting surface that abuts against the restricting surface of the stopper, so that the magnetic pole surface of the electromagnet (stator) and the electromagnet of the armature An appropriate air gap can be secured between the side end surfaces. Along with this, it is possible to prevent poor response due to residual magnetism after the supply current (excitation current) to the electromagnet (coil) is cut off. In addition, by forming the groove bottom surface of the radial groove in an arc shape or a taper shape, a flat magnetic efficiency may be obtained even if the movement amount (lift amount) of the armature with respect to the magnetic pole surface of the electromagnet changes.
According to the eighth aspect of the present invention, the space on the inner peripheral side of the side wall of the stopper may be used as a spring chamber that houses a spring that applies a load in a direction in which the armature is separated from the regulating surface of the stopper.

According to the ninth aspect of the present invention, the electromagnetic actuator for a fuel injection device may be applied to an injector electromagnetic valve for injecting and supplying fuel to a cylinder of an internal combustion engine. Here, the injector solenoid valve is provided with a leak port for allowing excess fuel to overflow from the armature chamber of the injector solenoid valve to the low pressure side of the fuel system. The space on the inner peripheral side of the side wall of the stopper is open toward the leak port on the opposite side to the armature side.
In this case, when the armature comes into contact with the restriction surface of the stopper, the surplus fuel in the armature chamber (the fuel passage formed between the magnetic pole surface of the electromagnet and the armature) is the gap between the electromagnet and the stopper, the stopper The excess fuel in the space on the inner peripheral side of the stopper side wall passes from the leak port of the injector solenoid valve to the outside (of the fuel system). It is discharged to the low pressure side. As a result, even when the armature comes into contact with the restriction surface of the stopper, the fuel discharge passage for discharging excess fuel to the outside is not blocked.

According to the tenth aspect of the present invention, the electromagnetic actuator for a fuel injection device may be applied to an injector electromagnetic valve for injecting and supplying fuel to a cylinder of an internal combustion engine. Here, the injector solenoid valve is provided with a housing that holds and fixes the opposite end of the stopper with respect to the armature side. The space on the inner peripheral side of the side wall of the stopper is liquid-tightly closed by the housing on the opposite side to the armature side. That is, the space on the inner peripheral side of the side wall of the stopper is a bag hole.
In this case, when the armature comes into contact with the restriction surface of the stopper, the fuel in the space on the inner peripheral side of the stopper side wall passes through the through hole and the annular groove on the side wall of the stopper, and reaches the armature chamber (the magnetic pole surface of the electromagnet and the armature). To the fuel passage formed between the two. Thereby, even if the armature is in contact with the restriction surface of the stopper, the fuel in the space on the inner peripheral side of the side wall of the stopper is not increased.

According to the eleventh and twelfth aspects of the present invention, when the armature is pulled up by the electromagnetic force of the electromagnet and comes into contact with the restriction surface of the stopper, the injector solenoid valve is opened. That is, the valve of the solenoid valve for injector opens the valve hole of the valve seat.
For this reason, if the passage length in the axial direction of the gap is long and the pressure and flow rate of the fuel passing through the gap is reduced by the orifice effect, the injector solenoid valve (its own valve) is opened and then the injector (nozzle needle) ) Until the valve is opened (valve opening delay time) becomes longer and the injection quantity characteristic of the injector changes. However, as in the first and fourth aspects, the through hole and the annular By arranging the groove closer to the armature than the central portion of the stopper in the axial direction or in the vicinity of the regulating surface, it is possible to avoid the occurrence of the above problems.

The best mode for carrying out the present invention is to improve the wear resistance at the contact portion between the armature and the stopper, with a gap provided between the electromagnet and the stopper, and the outer periphery of the stopper side wall in the circumferential direction. This is realized by providing an annular groove that surrounds the inner wall of the stopper and a through hole that communicates the space on the inner peripheral side of the stopper side wall and the annular groove provided on the outer periphery of the stopper side wall.
An annular groove that provides a gap between the electromagnet and the stopper and surrounds the outer periphery of the stopper side wall in the circumferential direction is for the purpose of suppressing a change in the armature lift while preventing a decrease in the electromagnetic force of the electromagnet. This is realized by providing a through hole that communicates the space on the inner peripheral side of the side wall of the stopper and the annular groove provided on the outer periphery of the side wall of the stopper.
The purpose of improving the wear resistance at the contact portion between the armature and the stopper while preventing the pressure and flow rate of the fuel passing through the gap between the electromagnet and the stopper from being lowered is to be improved. This is realized by disposing the stopper on the armature side of the side wall of the stopper in the axial direction or in the vicinity of the regulating surface.

[Configuration of Example 1]
1 to 4 show Embodiment 1 of the present invention. FIG. 1 is a view showing a common rail fuel injection system, FIG. 2 is a view showing an injector, and FIG. 3 is a view showing an injector solenoid valve. FIG.

  The fuel injection device for an internal combustion engine of the present embodiment is mounted in an engine room of a vehicle such as an automobile, and is mainly a fuel injection system for an internal combustion engine (multi-cylinder diesel engine: hereinafter referred to as an engine) such as a diesel engine. It is a common rail type fuel injection system (accumulation type fuel injection device) known as. This common rail fuel injection system includes a supply pump (fuel injection pump, fuel supply pump) 2 having a built-in feed pump (not shown) for pumping low pressure fuel from a fuel tank 1 on the low pressure side of the fuel system, and the supply pump. 2 and a plurality of (four in this example) injectors (injectors for a diesel engine) 4 to which high pressure fuel is distributed and supplied from each fuel outlet of the common rail 3. The high-pressure fuel accumulated in the common rail 3 is injected and supplied into the combustion chamber of each cylinder of the engine via each injector 4.

  Here, the amount of current supplied to the solenoid valve (fuel metering valve) 10 of the supply pump 2 and each solenoid valve (injector solenoid valve) 12 of the plurality of injectors 4 is determined by the pump drive circuit (not shown) and the injector drive. It is configured to be controlled by an engine control unit (hereinafter referred to as ECU) that includes a circuit (EDU). The ECU includes a CPU that performs control processing and arithmetic processing, a storage device (memory such as ROM and RAM) that stores various programs and control data, an input circuit (input unit), an output circuit (output unit), and the like. The microcomputer of the known structure, the pump drive circuit connected to the solenoid valve 10 of the supply pump 2, and the injector drive circuit (EDU) connected to each solenoid valve 12 of the several injector 4 are incorporated.

  The electric signal from the fuel pressure sensor (common rail pressure sensor) 20 attached to the common rail 3 and the sensor signals from various sensors are A / D converted by the A / D converter and then input to the microcomputer. It is configured as follows. Here, not only the common rail pressure sensor 20 but also a crank angle sensor, an accelerator opening sensor, a coolant temperature sensor, a fuel temperature sensor, and the like are connected to the input portion of the microcomputer. The microcomputer also has a function as a rotational speed detecting means for detecting the engine rotational speed (NE) by measuring the interval time of NE signal pulses output from the crank angle sensor.

  Further, when an ignition switch (not shown) is turned on (IG / ON), the microcomputer controls the fuel injection pressure into the combustion chamber for each cylinder of the engine and each injector 4 based on the control program stored in the memory. The fuel injection timing and the fuel injection amount from each injector 4 are calculated, the amount of current supplied to the coil of the solenoid valve 10 of the supply pump 2 (so-called pump drive current), and each solenoid valve 12 of the plurality of injectors 4 The amount of current supplied to the coil 13 (so-called pump drive current) is electronically controlled.

  The supply pump 2 includes a feed pump having a known structure, a cam (not shown) driven by a pump drive shaft (drive shaft, cam shaft, etc.) 21, and top dead center and bottom dead center driven by the cam. One or a plurality of plungers (not shown) that reciprocate linearly between and a cylinder head fixed to the pump housing and having one or a plurality of pressurizing chambers formed therein. Yes. The feed pump is a low-pressure supply pump that pumps low-pressure fuel from the fuel tank 1 through the low-pressure pump pipe 22 by rotating the pump drive shaft 21 with the rotation of the crankshaft of the engine. A fuel filter 23 is installed in the middle of the low-pressure pump pipe 22 that connects the fuel tank 1 and the fuel inlet (inlet) of the feed pump.

  The supply pump 2 is sucked from the fuel tank 1 into one or a plurality of pressurizing chambers through the low pressure pump pipe 22, the feed pump, and the fuel suction path as each plunger reciprocates in the cylinder head. This is a high-pressure supply pump that pressurizes the low-pressure fuel to increase the pressure. Further, the supply pump 2 is provided with a leak port so that the internal fuel temperature does not become high. Leak fuel (including surplus fuel) from the supply pump 2 passes through the relief pipe 29 to the fuel tank 1. Returned. Here, in the middle of the fuel suction path from the feed pump to one or more pressurizing chambers, an electromagnetic valve 10 for adjusting the amount of fuel sucked into one or more pressurizing chambers is attached. It has been. The electromagnetic valve 10 is configured to be electronically controlled by the amount of supply current applied from the ECU. Thereby, the fuel discharge amount discharged from the supply pump 2 is controlled.

  The common rail 3 is a pressure accumulating container for accumulating high-pressure fuel corresponding to the fuel injection pressure, and is connected to a fuel discharge port (outlet) of the supply pump 2 via a high-pressure pump pipe 24 and includes a plurality of injector pipes 25. It is connected to each injector 4 via. Further, the common rail 3 is provided with a leak port so as to keep the internal fuel pressure at an optimum value, and the leak fuel from the common rail 3 is returned to the fuel tank 1 through the relief pipe 29. Here, a pressure limiter 26 is liquid-tightly attached to the leak port of the common rail 3. The pressure limiter 26 is a pressure safety valve that opens when the internal pressure of the common rail 3 (so-called common rail pressure) exceeds the limit set pressure to keep the internal pressure of the common rail 3 below the limit set pressure. Instead of the pressure limiter 26, a pressure reducing valve may be liquid-tightly attached to the leak port of the common rail 3. This pressure-reducing valve is an electromagnetic valve that is excellent in pressure-lowering performance by quickly reducing the internal pressure of the common rail 3 from a high pressure to a low pressure, for example, when decelerating or when the engine is stopped, by being electronically controlled by the amount of current supplied from the ECU .

  The plurality of injectors 4 of the present embodiment are mounted corresponding to each cylinder of the engine, and are a direct injection type internal combustion engine that injects high pressure fuel accumulated in the common rail 3 directly into the combustion chamber in a mist form. This is an engine fuel injection valve. Each injector 4 is connected to the downstream end in the fuel flow direction of a plurality of injector pipes 25 branched from the common rail 3, and a fuel injection nozzle 11 that injects fuel into the combustion chamber of each cylinder of the engine, and the fuel injection This is an electromagnetic fuel injection valve composed of an electromagnetic valve 12 or the like that drives the valve body of the nozzle 11 in the valve opening direction. In addition, a top return tube 28 having a leak port 27 formed therein is provided at the upper end portion of each solenoid valve 12 of the plurality of injectors 4 in the figure.

  The fuel injection nozzle 11 includes an injector body (injector body) 31 including a nozzle body and a nozzle holder connected to the nozzle body, and a nozzle needle (valve body of the fuel injection nozzle) 32 accommodated in the injector body 31. Yes. A nozzle injection hole portion for injecting fuel into the combustion chamber of each cylinder of the engine, that is, a plurality of injection holes 33 is provided at the lower end portion of the injector main body 31 in the figure. An axial hole that extends straight from the contact surface to which the orifice plate 34 is in close contact with the nozzle injection hole side is provided inside the injector body 31. Inside this axial hole, a nozzle needle 32 that opens and closes a plurality of injection holes 33 and a command piston 35 connected to the upper end of the nozzle needle 32 are slidably accommodated. The portion that slides with the first sliding portion (large diameter portion) of the nozzle needle 32 functions as a first sliding hole, and also slides with the second sliding portion (large diameter portion) of the command piston 35. The moving part functions as a second sliding hole.

  A fuel reservoir chamber 36 is formed as a first pressure chamber in which the oil pressure of the fuel introduced inside acts in the valve opening direction of the nozzle needle 32 on the lower side of the axial direction of the axial hole in the figure. Yes. In addition, a pressure control chamber 37 as a second pressure chamber is formed on the upper side of the axial direction of the axial hole in the axial direction in which the oil pressure of the fuel introduced therein acts in the valve closing direction of the nozzle needle 32. Yes. Furthermore, a spring accommodating chamber 39 for accommodating a spring (needle urging means) 38 that urges the nozzle needle 32 in the valve closing direction is formed in the central portion of the axial hole in the axial direction. Inside the injector main body 31, a fuel reservoir chamber 36 and a pressure control chamber 37 are connected to each fuel outlet of the common rail 3 through each injector pipe 25 from a pipe joint part (fuel inlet part of the injector 4) 40. A fuel supply passage (high-pressure fuel passage) 41 for supplying high-pressure fuel to is formed.

The pressure control chamber 37 communicates with the fuel supply passage 41 via the inlet-side orifice 42, and passes through the central portion of the orifice plate 34. The outlet-side orifice 43, the solenoid valve 12-side valve chamber 44, and the fuel discharge passage It communicates with the armature chamber 46 on the electromagnetic valve 12 side via 45 (both see FIG. 10). As shown in FIG. 10, the inlet-side orifice 42 and the outlet-side orifice 43 may be formed on one or a plurality of orifice plates.
The injector main body 31 of the fuel injection nozzle 11 is provided with a leak port 48 in parallel with the outlet-side orifice 43, and leak fuel (including surplus fuel) from the fuel injection nozzle 11 is supplied to the solenoid valve 12 side. The armature chamber 46 is configured to flow into the armature chamber 46.

  For the leaked fuel that flows into the electromagnetic valve 12 from the fuel injection nozzle 11, the sliding gap between the first sliding hole of the injector body 31 and the first sliding portion of the nozzle needle 32 from the fuel reservoir chamber 36. In addition to the leaked fuel that overflows into the spring housing chamber 39 through the fuel discharge passage 47 and reaches the leak port 48 through the fuel discharge passage 47, the sliding of the command piston 35 and the second sliding hole of the injector body 31 from the pressure control chamber 37. There is a leaked fuel that overflows into the spring accommodating chamber 39 through a sliding gap with the portion (large diameter portion) and reaches the leak port 48 through the fuel discharge passage 47.

  The solenoid valve 12 is integrally assembled with the rear end portion (the upper end portion in the figure) of the injector main body 31 of the fuel injection nozzle 11 and fuel that drives the nozzle needle 32 accommodated in the injector main body 31 in the valve opening direction. It is an electromagnetic actuator for injection devices. The electromagnetic valve 12 includes a valve 5 (see FIG. 10) for opening and closing the outlet-side orifice (valve hole) 43, an electromagnet 6 having a coil 13 that generates a magnetic force when energized, and a magnetic pole of the electromagnet 6. The armature 7 attracted | sucked to the surface side, the stopper 9 arrange | positioned inside the electromagnet 6, and the housing which forms the armature chamber 46 inside are provided.

  Here, the housing of the solenoid valve 12 is arranged so as to surround the housing (block) 51 having the top return tube 28, the connector 52 arranged so as to surround the top return tube 28, and the electromagnet 6. Between the stator case 53 provided, the retaining nut 54 disposed so as to surround each component of the solenoid valve 12 including the armature 7, and the magnetic pole surface of the electromagnet 6 and the regulating surface of the stopper 9, The valve body 55 (see FIG. 10) that forms the armature chamber 46 is used.

  Here, in the injector 4 of this embodiment, the orifice plate 34 is sandwiched between the contact surface of the injector body 31 (contact surface of the fuel injection nozzle 11) and the contact surface of the valve body 55 (contact surface of the electromagnetic valve 12). In this state, the retaining nut 54 is fastened and fixed to the outer periphery of the injector body 31 so that the contact surface of the fuel injection nozzle 11 and the contact surface of the solenoid valve 12 are brought into close contact with each other with a predetermined fastening axial force. The nozzle 11 and the solenoid valve 12 are integrated (see FIG. 10). An O-ring (seal material) 56 is attached between the outer periphery of the housing 51 and the inner periphery of the retaining nut 54 to prevent leakage of fuel from the inside of the solenoid valve 12 to the outside.

  The valve 5 is a spherical body-shaped valve body (ball valve) held on the distal end side of the shaft-like portion 59 of the armature 7, and the opening peripheral portion (valve) of the outlet-side orifice 43 of the orifice plate (valve seat) 34. The outlet side orifice 43 that functions as the valve hole of the electromagnetic valve 12 is closed and opened by being seated and removed from the seat portion. The valve 5 is seated on the orifice plate 34 to close the outlet-side orifice 43 by a valve driving device (electromagnetic actuator), and is separated from the orifice plate 34 to open the outlet-side orifice 43. Driven to two positions, the valve fully open position.

  The electromagnet 6 constituting the main component of the electromagnetic actuator includes a coil 13 that generates a magnetic flux when energized, and a stator 14 that is magnetized when an excitation current (injector drive current) flows through the coil 13. Has been. The coil 13 is wound around the outer periphery of a resin coil bobbin 15 housed in the coil housing portion of the stator 14 a plurality of times with a conductive wire coated with an insulating coating. Force). And the coil 13 has a coil part wound between a pair of hook-shaped parts of the coil bobbin 15, and a pair of terminal lead wires taken out from this coil part. A pair of terminals (external connection terminals) 19 held by the connector 52 are electrically connected to the pair of terminal lead wires via the connection terminals 16 and 17.

  The stator 14 is made of a soft magnetic material such as pure iron or low carbon steel (or ferritic stainless steel: SUS13), and is opposed to the plate portion 57 of the armature 7 with a predetermined gap therebetween. The magnetic pole surface 61 is arranged. The outer diameter side of the stator 14 in the radial direction with respect to the coil storage portion is protected by a substantially cylindrical stator case 53. A cylindrical fitting portion 62 having a fitting hole therein is provided on the inner diameter side in the radial direction from the coil housing portion of the stator 14.

  The armature 7 is formed of a soft magnetic material such as pure iron or low carbon steel (or ferritic stainless steel: SUS13), and is attracted to the magnetic pole surface side of the stator 14 by the electromagnetic force of the stator 14 of the electromagnet 6. The As a result, the valve 5 is separated from the orifice plate 34 to open the outlet-side orifice 43. Further, when the energization to the coil 13 is stopped, the armature 7 moves in the valve closing direction by the urging force (spring load) of the coil spring 63 and presses the valve 5 against the orifice plate 34. As a result, the valve 5 is seated on the orifice plate 34 to close the outlet-side orifice 43.

  That is, when the armature 7 is pushed back downward in the figure by the biasing force of the coil spring 63 and the armature 7 moves toward the upper end face in the figure of the orifice plate 34, the amount of movement of the armature 7 is changed. It is used as the first regulation surface that regulates Thus, when the valve 5 is seated on the first restriction surface of the orifice plate 34, further movement of the valve 5 and the armature 7 is restricted. That is, the position of the valve 5 is the default position. Along with this, the position of the armature 7 is regulated at the default position. Therefore, the electromagnetic valve 12 of the present embodiment constitutes a normally closed type (normally closed type) electromagnetic on-off valve.

  The armature 7 of the present embodiment includes a plate portion 57 disposed opposite to the magnetic pole surface 61 of the electromagnet 6 and a sliding hole of the valve body 55 that protrudes from the plate portion 57 to the opposite side to the stator side in the axial direction. It has a shaft-like portion 59 that is slidably supported therein. The plate portion 57 and the shaft-like portion 59 may be configured as separate parts, and both may be coupled by press-fitting or welding. In this case, bearing steel having excellent sliding resistance may be used as the material of the shaft-like portion 59. The plate portion 57 includes an end surface on the stator side facing the magnetic pole surface 61 of the electromagnet 6 (an end surface on the electromagnet side: an abutting surface abutting against the regulating surface of the stopper 9), A plurality of through holes 64 penetrating the plate portion 57 in the axial direction are formed. These through holes 64 allow unnecessary fuel to be sandwiched between the magnetic pole surface 61 of the stator 14 of the electromagnet 6 and the stator side end surface of the armature 7 when the armature 7 comes into contact with the restriction surface of the stopper 9. Is formed.

  Here, in the solenoid valve 12 of the present embodiment, in order to prevent poor response due to residual magnetism after the exciting current flowing through the coil 13 is interrupted, even when the armature 7 is fully lifted, the stator side of the plate portion 57 of the armature 7 An appropriate axial gap (air gap) is secured between the end face and the magnetic pole face 61 of the stator 14. The air gap is secured by an annular protrusion (locked portion) 65 that protrudes from the center of the plate portion 57 of the armature 7 to the stopper side by a predetermined protrusion amount (air gap). As shown in FIG. 4, an annular contact surface 66 that contacts the regulating surface of the stopper 9 when the armature 7 is fully lifted is provided on the surface of the protrusion 65 of the armature 7.

  Further, as shown in FIG. 4, only a plurality of fuel escape grooves 67 extending from the outer periphery of the contact surface 66 toward the respective through holes 64 are provided on the stator side end surface of the plate portion 57 of the armature 7. . Alternatively, the armature 7 is provided with only a plurality of radial grooves 69 on the stator side end surface including the contact surface 66. Here, the plurality of fuel escape grooves 67 have a groove width (α) of, for example, 0.8 mm, a groove depth of, for example, 0.5 mm, and the armature 7 is pulled upward by the electromagnetic force of the electromagnet 6 so that the armature 7 is a recess (fuel passage groove) for allowing fuel to escape so that a fuel discharge passage, which will be described later, is not blocked when the abutment surface 66 of the projection portion 65 abuts against the restriction surface of the stopper 9. The plurality of radial grooves 69 are extremely shallow and narrow recesses (grooves) for preventing flatness or linking.

  The stopper 9 of this embodiment is formed in a cylindrical shape by a metal material such as chromium / molybdenum steel. The stopper 9 is desirably formed of a nonmagnetic material in order to prevent a response failure due to residual magnetism after the exciting current flowing through the coil 13 is cut off. This stopper 9 is a cylindrical wall portion (in the axial direction) that extends straight from the opening end portion (first end) on the armature side toward the opening end portion (second end) on the opposite side to the armature side in the axial direction. The stopper 9 has a side wall and a cylindrical wall portion 71.

  Further, the lower end portion (first end) of the cylindrical wall portion 71 of the stopper 9 is lifted upward by the electromagnetic force of the stator 14 of the electromagnet 6 so that the armature 7 moves to the magnetic pole surface side of the stator 14. This is used as a second restriction surface (hereinafter abbreviated as a restriction surface) 72 for restricting the movement amount (full lift amount) of the armature 7. As a result, when the contact surface 66 of the projection 65 of the armature 7 contacts the restriction surface 72 of the stopper 9, further movement of the armature 7 is restricted. That is, the position of the armature 7 becomes the full lift position. Along with this, the lift amount of the valve 5 is also regulated at the full lift position.

  The upper end side (second end side) in the axial direction of the cylindrical wall portion 71 of the stopper 9 is a fitting portion (fitting hole) 73 provided on the inner peripheral portion of the housing 51 as shown in FIG. It is held and fixed inside by press fitting. The cylindrical wall 71 of the stopper 9 has an outer diameter that is smaller than the inner diameter of the stator 14 of the electromagnet 6. That is, an appropriate tube is provided between the inner peripheral surface (hole wall surface of the fitting hole) of the fitting portion 62 of the stator 14 of the electromagnet 6 and the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 so as not to interfere with each other. A gap 75 is formed. The cylindrical gap 75 is always in communication with the armature chamber 46 because the opening side end portion provided below in the drawing is opened on the outer peripheral side of the contact surface 66 of the projection 65 of the armature 7. . That is, the cylindrical gap 75 is a case where the armature 7 is pulled up by the electromagnetic force of the electromagnet 6 and the contact surface 66 of the projection 65 of the armature 7 contacts the restriction surface 72 of the stopper 9. In addition, it is possible to communicate with a fuel passage 74 formed between the magnetic pole surface 61 of the stator 14 of the electromagnet 6 and the stator side end surface of the armature 7.

  The stopper 9 has a plurality of (three or four in this example) through holes 77 so as to penetrate the annular groove 76 and the cylindrical wall 71 so as to surround the outer periphery of the cylindrical wall 71 in the circumferential direction. Is provided. In addition, a space that extends straight in the axial direction from the first end side to the second end side is provided inside the cylindrical wall portion 71. The space in the cylindrical wall 71 accommodates a coil spring 63 that applies a spring load to the armature 7 in a direction in which the contact surface 66 of the projection 65 of the armature 7 is separated from the regulating surface 72 of the stopper 9. It is used as chamber 79.

  The annular groove 76 is annularly provided on the outer peripheral surface of the cylindrical wall 71 so as to connect all the through holes 77. The annular groove 76 is recessed by a predetermined groove depth from the outer peripheral surface of the cylindrical wall portion 71 toward the inner peripheral side of the cylindrical wall portion 71 so as to increase the passage sectional area of the cylindrical gap 75 (for example, cutting) The outer diameter is cut by machining). The groove depth of the annular groove 76 is substantially the same as the passage length in the radial direction of the plurality of through holes 77. The plurality of through holes 77 penetrate the cylindrical wall portion 71 in a radial direction substantially orthogonal to the axial direction of the cylindrical wall portion 71, for example, from the outer peripheral surface of the cylindrical wall portion 71 toward the inner peripheral surface. The opening on the outer diameter side in the radial direction is opened at the groove bottom surface of the annular groove 76, and the opening on the inner diameter side in the radial direction is formed on the inner peripheral surface of the cylindrical wall portion 71. Open. These through-holes 77 communicate with the annular groove 76 and the spring accommodating chamber 79 through the through-holes themselves, and are always connected to the armature chamber 46, that is, the fuel passage 74 through the cylindrical gap 75 and the annular groove 76. Communicate. The annular groove 76 and the plurality of through-holes 77 are disposed on the armature side with respect to the axial center of the cylindrical wall portion 71 of the stopper 9, particularly in the vicinity of the regulation surface of the cylindrical wall portion 71 of the stopper 9. .

  In the spring accommodating chamber 79, the opening on the lower side (first end side) of the cylindrical wall portion 71 of the stopper 9 opens toward the armature chamber 46. The spring accommodating chamber 79 has an opening on the upper side (second end side) of the cylindrical wall portion 71 of the stopper 9 in the leak port 27 of the top return tube 28 via the fuel discharge passage 80 in the housing 51. It is open toward. As a result, the leaked fuel that has flowed into the armature chamber 46 of each solenoid valve 12 from each fuel injection nozzle 11 of the plurality of injectors 4 is discharged from the leak port 27 of each solenoid valve 12 to the relief pipe 29. After that, it is returned to the fuel tank 1.

[Operation of Example 1]
Next, the operation of the injector 4 provided with the electromagnetic valve 12 of this embodiment will be briefly described with reference to FIGS.

When a pulsed injector drive current is applied to each coil 13 of each of the plurality of injectors 4 mounted corresponding to each cylinder of the engine from the ECU via the injector drive circuit, the coil 13 and the stator 14 Electromagnetic force is generated in the electromagnet 6 formed. The armature 7 is attracted to the magnetic pole surface side of the stator 14 by the electromagnetic force of the electromagnet 6.
Then, the armature 7 moves in a direction approaching the magnetic pole surface 61 of the electromagnet 6 (one side in the axial direction), and the abutment surface 66 of the projection 65 of the armature 7 contacts the regulating surface 72 of the cylindrical wall portion 71 of the stopper 9. Abut. Thereby, the position of the armature 7 is regulated at the full lift position.

  At this time, high pressure fuel is introduced into the pressure control chamber 37 upstream of the valve 5 (and the valve chamber 44) in the fuel flow direction from the common rail 3 through the inlet side orifice 42. Further, the inside of the fuel discharge passage 45 on the downstream side in the fuel flow direction from the valve 5 (and the valve chamber 44) is via an armature chamber 46, a spring accommodating chamber 79, a fuel discharge passage 80, a leak port 27, and a relief pipe 29. The fuel tank 1 communicates with the low pressure side of the fuel system.

  For this reason, since the fuel pressure is higher on the upstream side in the fuel flow direction than on the valve 5 than on the downstream side in the fuel flow direction on the valve 5, the armature 7 moves (lifts) upward in the axial direction. At the same time, the valve 5 is detached from the orifice plate 34 and the outlet-side orifice 43 of the orifice plate 34 is opened. Therefore, the fuel filled in the pressure control chamber 37 flows into the armature chamber 46 from the pressure control chamber 37 through the outlet orifice 43 → the valve chamber 44 → the fuel discharge passage 45.

  Here, when the armature 7 is pulled upward by the electromagnetic force of the electromagnetic valve 6 and the contact surface 66 of the projection 65 of the armature 7 contacts the restriction surface 72 of the cylindrical wall portion 71 of the stopper 9, the fuel discharge passageway. As a result, the opening on the first end side of the spring accommodating chamber 79 that functions as is closed. However, the electromagnetic valve 12 of this embodiment is provided with a cylindrical gap 75 between the inner peripheral surface of the fitting portion 62 of the stator 14 of the electromagnet 6 and the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9. An annular groove 76 is provided on the outer peripheral surface of the cylindrical wall portion 71, and a plurality of through holes 77 for communicating the spring accommodating chamber 79 and the annular groove 76 are provided.

  Therefore, the leaked fuel that has flowed into the armature chamber 46 passes through a fuel passage 74 formed between the magnetic pole surface 61 of the stator 14 and the stator side end surface (and the plurality of fuel escape grooves 67) of the plate portion 57 of the armature 7. Then, it flows into the cylindrical gap 75 between the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the inner peripheral surface of the fitting portion 62 of the stator 14. The leaked fuel that has flowed into the cylindrical gap 75 passes through the annular groove 76 on the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the plurality of through holes 77 that penetrate the cylindrical wall portion 71 of the stopper 9 from the cylindrical gap 75. And flows into the spring accommodating chamber 79.

  The leaked fuel that has flowed into the spring accommodating chamber 79 flows out from the second end of the cylindrical wall portion 71 of the stopper 9, passes through the fuel discharge passage 80 and the leak port 27, and is discharged to the outside of the electromagnetic valve 12. That is, the leaked fuel discharged from the electromagnetic valve 12 is returned to the fuel tank 1 through the relief pipe 29. Accordingly, even when the contact surface 66 of the projection 65 of the armature 7 contacts the restriction surface 72 of the cylindrical wall portion 71 of the stopper 9, the fuel discharge passage (spring housing chamber 79, fuel discharge passage 80, leak The port 27 or the like is not blocked by the projection 65 of the armature 7.

  As the solenoid valve itself opens, the fuel pressure in the pressure control chamber 37 (the oil pressure acting in the direction in which the nozzle needle 32 is pushed down (the valve closing direction)) decreases, and the fuel in the fuel reservoir chamber 36 is reduced. The pressure (the oil pressure acting in the direction in which the nozzle needle 32 is pushed up (the valve opening direction)) acts on the oil pressure in the pressure control chamber 37 in the urging force of the spring 38 (the direction in which the nozzle needle 32 is pushed down (the valve closing direction)). It becomes larger than the combined force of adding the urging force. Thereby, since the nozzle needle 32 separates from the valve seat (seat surface) of the injector main body 31, the plurality of injection holes 33 are opened. That is, the valve body (nozzle needle 32) of the fuel injection nozzle 11 is opened, and high-pressure fuel accumulated in the common rail 3 is injected and supplied into the combustion chamber of each cylinder of the engine. Therefore, fuel injection into the combustion chamber for each cylinder of the engine is started.

  When the command injection period elapses from the injection timing, the energization of the coil 13 of the solenoid valve 12 is stopped by the ECU. Then, the armature 7 is moved away from the magnetic pole surface 61 of the electromagnet 6 by the urging force of the coil spring 63, and the valve 5 is pressed against the orifice plate 34. As a result, the outlet-side orifice 43 is closed, so that the high-pressure fuel supplied from the common rail 3 to the pressure control chamber 37 via the fuel supply passage 41 and the inlet-side orifice 42 is filled in the pressure control chamber 37. Accordingly, the fuel pressure in the pressure control chamber 37 rises, and when the resultant force obtained by adding the urging force of the spring 38 to the fuel pressure in the pressure control chamber 37 becomes larger than the fuel pressure in the fuel reservoir chamber 36, the nozzle Since the needle 32 is seated on the valve seat (seat surface) of the injector body 31, the plurality of injection holes 33 are closed. That is, the valve body (nozzle needle 32) of the fuel injection nozzle 11 is closed, and fuel injection into the combustion chamber for each cylinder of the engine is completed.

[Features of Example 1]
Here, in recent years, in order to cope with stricter exhaust gas regulations of diesel engines, not only the fuel injection pressure is increased, but also the solenoid valve 12 is operated twice or more during one combustion process (720 ° CA) of the engine. A technology for performing valve opening driving and performing minute injection (pilot injection) before and after main injection (main injection) is progressing. Along with this, the solenoid valve 12 is required to have a very fast operation response and a highly accurate injection amount controllability. In order to realize such performance, it is necessary to drive the valve 5 of the solenoid valve itself to open and close in a short time.

Therefore, it is necessary to increase the electromagnetic force of the electromagnet 6 and the spring load of the coil spring 63 that urges the valve 5 and the armature 7 in the valve closing direction as compared with the current one. In addition to an increase in the collision force with which the abutment surface 66 of the projection 65 of the armature 7 collides with the restriction surface 72 of the cylindrical wall 71 of the stopper 9, the armature 7 and the stopper 9 are subjected to a single combustion process of the engine. The number of collisions will be several times that of the current one.
Along with this, there is a concern that the amount of wear at the contact portion between the armature 7 and the stopper 9 becomes very large. Therefore, it is necessary to increase the contact area between the armature 7 and the stopper 9. However, reducing the inner diameter of the stopper 9 can reduce the spring load (coil of the coil spring 63 accommodated in the spring accommodating chamber 79). There is a restriction on the diameter, wire diameter, coil pitch), and increasing the outer diameter of the stopper 9 involves a decrease in the electromagnetic force of the electromagnet 6, so the contact area of the contact portion between the armature 7 and the stopper 9 is reduced. There was a problem that it could not be enlarged easily.

  Therefore, the operation stability of the valve 5 and the armature 7 of the electromagnetic valve 12 is not deteriorated, and the electromagnetic force of the electromagnet 6 is not reduced, and the contact surface 66 of the armature 7 and the regulating surface of the stopper 9 ( The purpose of improving the wear resistance of the contact portion between the contact surface 66 of the armature 7 and the restriction surface 72 of the stopper 9 by increasing (widening) the contact area of the contact portion with the contact surface 72. Thus, the internal structure of the electromagnetic valve 12, that is, the fuel discharge passage structure (leak fuel passage structure) inside the electromagnetic valve 12, is optimized as described above.

Therefore, the armature chamber 46, particularly the stator of the armature 7, is disposed inside the electromagnetic valve 12 of this embodiment, that is, between the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the inner peripheral surface of the fitting portion 62 of the stator 14. A cylindrical gap 75 communicating with the fuel passage 74 between the side end face (and the plurality of fuel escape grooves 67) and the magnetic pole face 61 of the stator 14 is provided. Further, an annular groove 76 communicating with the cylindrical gap 75 is provided on the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9. Further, the cylindrical wall portion 71 of the stopper 9 opens at the bottom surface of the annular groove 76, and the cylinder of the stopper 9 is communicated with the spring accommodating chamber 79 in the cylindrical wall portion 71 of the stopper 9 and the annular groove 76. A plurality of through holes 77 penetrating the wall portion 71 are provided.
That is, in the electromagnetic valve 12 of this embodiment, paying attention to the fact that a gap is always provided between the outer periphery of the cylindrical wall portion 71 of the stopper 9 and the inner periphery of the fitting portion 62 of the stator 14. When the armature 7 is pulled upward by the electromagnetic force of the valve 6 and the contact surface 66 of the projection 65 of the armature 7 contacts the restriction surface 72 of the cylindrical wall portion 71 of the stopper 9, the fuel discharge passage is not blocked. As described above, the cylindrical gap 75, the annular groove 76, and the plurality of through holes 77 are used as a fuel escape passage.

  Therefore, in the injector 4 employing the top return method as in the present embodiment, the armature 7 is pulled upward by the electromagnetic force of the solenoid valve 6 when the valve 5 of the solenoid valve itself is driven to open. Even when the abutment surface 66 of the protrusion 65 abuts against the restriction surface 72 of the cylindrical wall portion 71 of the stopper 9, the fuel in the armature chamber 46 causes the fuel passage 74, the cylindrical gap 75, the annular groove 76, and the plural It flows into the spring accommodating chamber 79 through the through holes 77. Accordingly, when the valve 5 of the solenoid valve itself is driven to open, when the armature 7 is pulled upward by the electromagnetic force of the solenoid valve 6, a large amount of leaked fuel is prevented from remaining in the fuel passage 74. Therefore, since the contact surface 66 of the projection 65 of the armature 7 quickly contacts the restriction surface 72 of the cylindrical wall portion 71 of the stopper 9, a very fast operation response can be obtained.

Here, in the solenoid valve 12 of the present embodiment, when the passage cross-sectional area of the fuel passage 74 is A, the total area of the cylindrical gap 75 is B, and the total area of the plurality of through holes 77 is C, A ≦ You may comprise so that the relationship of B and A <= C may be satisfied.
When the flow rate of leaked fuel discharged from the inside of the solenoid valve 12 is, for example, 50 mm ³ / st or less when the valve 5 of the solenoid valve itself is driven to open, the cylindrical gap 75 has a total area B of, for example, 1. If it is 2 mm ² (minimum passage cross-sectional area A of the fuel passage 74 at the upper part of the armature) and the diameter and number of the through holes 77 are set so that the total area C is 1.2 mm ² or more, the fuel discharge passage (The armature 7 can perform a stable operation, and an accurate fuel injection amount can be obtained). Further, when the fuel passage groove (fuel escape groove 67) remains in the armature 7 or the stopper 9, the total area of both fuel passages may be set to be 1.2 mm ² or more. Similarly, when there is a fuel passage, the total area may be set to be 1.2 mm ² or more.

Further, in the electromagnetic valve 12 of the present embodiment, the armature 7 is pulled upward by the electromagnetic force of the electromagnetic valve 6 so that the contact surface 66 of the projection 65 of the armature 7 is the regulating surface of the cylindrical wall portion 71 of the stopper 9. By using a cylindrical gap 75, an annular groove 76 and a plurality of through holes 77 as a fuel escape passage when abutting against the arm 72, it is provided on the abutting surface 66 of the armature 7 or the restricting surface 72 of the stopper 9. The existing fuel passage groove can be eliminated or reduced. For example, as shown in FIG. 4, the passage length of the plurality of fuel escape grooves 67 can be made shorter than the fuel escape groove 121 of FIG. 13, and the fuel escape grooves on the contact surface 66 of the armature 7 are eliminated. be able to.
That is, even if the fuel passage groove is not provided on the stator side end surface of the armature 7 or the restriction surface 72 of the stopper 9 or the area of the fuel passage groove such as the fuel escape groove 67 is reduced, The fuel in the passage 74 can flow into the spring accommodating chamber 79 in the cylindrical wall portion 71 of the stopper 9.

  As a result, the operation stability of the armature 7 is not deteriorated and the electromagnetic force of the electromagnet 6 is not lowered, and the contact surface 66 of the projection 65 of the armature 7 and the cylindrical wall portion 71 of the stopper 9 are regulated. The contact area of the contact portion with the surface 72 can be increased (enlarged). Along with this, the surface pressure at the contact portion between the armature 7 and the stopper 9 decreases, and the amount of wear at the contact portion between the armature 7 and the stopper 9 decreases. Therefore, since the wear resistance of the contact portion between the armature 7 and the stopper 9 can be improved, secular change in the lift amount of the armature 7 (for example, an increasing tendency of the lift amount of the armature 7) can be suppressed. As a result, an increase in the flow rate of leaked fuel discharged from the pressure control chamber 37 through the inside of the electromagnetic valve 12 to the outside can be suppressed, so that the fuel is injected from the injector 4 as the valve opening timing of the nozzle needle 32 changes. An increase in the fuel injection amount can be suppressed.

  Therefore, changes in engine performance, deterioration of exhaust gas emissions, and the like can be suppressed. In addition, since very fast operation responsiveness and highly accurate injection amount controllability can be obtained, the solenoid valve 12 is driven to open twice or more during one combustion process (720 ° CA) of the engine. Pilot injection can be effectively performed before and after main injection (main injection). That is, since the valve 5 of the solenoid valve itself can be driven to open and close in a short time, the solenoid valve 12 can cope with the recent tightening of exhaust gas regulations of diesel engines.

Here, FIG. 5 shows Comparative Example 1 relative to Example 1 of the present invention, and shows the electromagnetic valve 12 having no annular groove 76 on the outer periphery of the cylindrical wall portion 71 of the stopper 9. In contrast to Comparative Example 1, in the solenoid valve 12 of the present embodiment, as described above, the annular groove 76 is provided on the outer periphery of the cylindrical wall portion 71 of the stopper 9 so as to connect all the plurality of through holes 77. ing. This can improve the flowability of the leaked fuel flowing into the plurality of through holes 77 from the armature chamber 46, that is, the fuel passage 74 through the cylindrical gaps 75. The area can be narrowed. Further, even if one through-hole 77 of the plurality of through-holes 77 is blocked by foreign matter or the like, or the remaining through-hole 77 is blocked by foreign matter or the like leaving one through-hole 77. However, it is possible to suppress a decrease in the flowability of the leak fuel.
Further, in the solenoid valve 12 of the present embodiment, as described above, the passage of the cylindrical gap 75 between the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the inner peripheral surface of the fitting portion 62 of the stator 14 is cut off. An annular groove 76 is provided on the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 by denting from the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 toward the inner peripheral side of the cylindrical wall portion 71 so as to increase the area. Yes.

  Accordingly, even if the inner diameter of the fitting portion 62 of the stator 14 of the electromagnet 6 is not so large, the gap between the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the inner peripheral surface of the fitting portion 62 of the stator 14. Since the cylindrical gap 75 can be formed, the reduction of the magnetic pole area of the stator 14 can be suppressed, and the decrease of the electromagnetic force of the electromagnet 6 can be suppressed. Therefore, it is not necessary to increase the outer diameter of the coil 13 of the electromagnet 6 so that the electromagnetic force of the electromagnet without a gap between the stopper 9 and the stator 14 is increased. ), That is, an increase in the size of the solenoid valve 12 can be suppressed. As a result, it is possible to improve the mountability of the electromagnetic valve 12 on a vehicle such as an automobile, that is, the engine, that is, the mountability of the injector 4.

  Further, in the electromagnetic valve 12 of the present embodiment, as described above, the cylindrical wall portion 71 of the stopper 9 is formed by making the groove depth of the annular groove 76 substantially the same as the passage length of the plurality of through holes 77. Strength reduction can be suppressed. Further, in the electromagnetic valve 12 of the present embodiment, as described above, the annular groove 76 and the plurality of through holes 77 are provided on the armature side, particularly the restriction surface, with respect to the axial center of the cylindrical wall portion 71 of the stopper 9. It is arranged in the vicinity. Accordingly, the axial length of the cylindrical gap 75 between the outer peripheral surface of the cylindrical wall portion 71 of the stopper 9 and the inner peripheral surface of the fitting portion 62 of the stator 14 is shortened. Even when the cylindrical gap 75 is narrowed to the minimum required passage sectional area, the axial length of the cylindrical gap 75 is short, so that the leak fuel pressure and the leak fuel flow rate that pass through the cylindrical gap 75 are difficult to decrease. Become. Accordingly, the time (opening delay time) from when the valve 5 of the solenoid valve itself opens until the nozzle needle 32 and the command piston 35 start to lift does not increase, and the injection of the injector 4 Changes in the quantity characteristics can be suppressed.

  FIG. 6 shows a second embodiment of the present invention and is a view showing an injector solenoid valve.

  The stopper 9 of the electromagnetic valve 12 of the present embodiment has a flange portion 90 that extends in a bowl shape from the outer periphery of the upper end portion of the cylindrical wall portion 71 in the figure. The stopper 9 is held inside the fitting portion 62 of the stator 14 while being sandwiched between the illustrated upper end surface of the stator 14 of the electromagnet 6 and the illustrated lower end surface of the housing 51. Further, the electromagnetic valve 12 of the present embodiment has a fuel discharge passage 91 in addition to a fuel escape passage made up of a cylindrical gap 75, an annular groove 76, a plurality of through holes 77 and a spring accommodating chamber 79.

  In the fuel discharge passage 91, the armature 7 is pulled upward by the electromagnetic force of the electromagnetic valve 6, and the contact surface 66 of the projection 65 of the armature 7 contacts the regulation surface 72 of the cylindrical wall portion 71 of the stopper 9. At this time, leaked fuel in the armature chamber 46 causes the cylindrical gap 93 between the outer periphery of the stator 14 of the electromagnetic valve 6 and the inner periphery of the stator case 53, the upper end surface of the flange portion 90 of the stopper 9, and the housing 51 to be illustrated. It flows into the fuel discharge passage 80 through an annular gap 94 between the lower end surface. Accordingly, the fuel passage groove provided in the armature 7 and the stopper 9 can be eliminated.

  Therefore, the contact surface 66 of the projecting portion 65 of the armature 7 and the regulation surface of the cylindrical wall portion 71 of the stopper 9 without deteriorating the operational stability of the armature 7 and without reducing the electromagnetic force of the electromagnet 6. The contact area of the contact part with 72 can be increased (enlarged). Thereby, it becomes possible to improve the wear resistance of the contact portion between the armature 7 and the stopper 9. Further, in the present embodiment, the flowability of the fuel in the spring accommodating chamber 79 becomes better than that in the first embodiment, and the rising speed of the armature 7 can be made faster.

  FIG. 7 shows a third embodiment of the present invention and is a view showing an injector solenoid valve.

  In the solenoid valve 12 of this embodiment, a stopper 9 that regulates the full lift amount of the armature 7 is held inside the fitting portion 62 of the stator 14 of the electromagnet 6. The upper end side (second end side) of the cylindrical wall portion 71 of the stopper 9 is held and fixed in the fitting portion (fitting hole) 73 of the housing 51 by press fitting. In the spring accommodating chamber 79 in the cylindrical wall portion 71 of the stopper 9, the opening on the first end side of the cylindrical wall portion 71 of the stopper 9 opens toward the armature chamber 46. In the spring accommodating chamber 79, the opening on the second end side of the cylindrical wall portion 71 of the stopper 9 is closed by the bottom surface of the fitting hole 73 of the housing 51. That is, in this embodiment, the spring accommodating chamber 79 is a bag hole, and leaked fuel that flows into the armature chamber 46 when the valve 5 of the solenoid valve itself opens is discharged from the leak port provided in the injector body 31 to the outside. A side return type solenoid valve 12 for discharging is employed.

  In the injector 4 of this embodiment, when the valve 5 of the solenoid valve itself is opened, the armature 7 is pulled upward by the electromagnetic force of the solenoid valve 6 so that the contact surface 66 of the projection 65 of the armature 7 is the stopper 9. When contacting the regulating surface 72 of the cylindrical wall portion 71, the fuel in the spring accommodating chamber 79 in the cylindrical wall portion 71 of the stopper 9 passes through the plurality of through holes 77, the annular groove 76 and the cylindrical gap 75, Since the fuel flows into the fuel passage 74 between the armature chamber 46, in particular, the stator side end surface (and the plurality of fuel escape grooves 67) of the armature 7 and the magnetic pole surface 61 of the stator 14, the fuel in the spring accommodating chamber 79 is increased in pressure. There is no.

The leaked fuel that has flowed out of the armature chamber 46 of the solenoid valve 12 into the fuel discharge passage inside the injector main body 31 is discharged to the outside from a leak port 119 (see FIG. 11) provided in the injector main body 31 to be relief. It returns to the fuel tank 1 through the pipe 29.
When the valve 5 of the solenoid valve itself is closed, when the armature 7 is pushed downward by the urging force of the coil spring 63 and the armature 7 is separated from the regulation surface 72 of the cylindrical wall portion 71 of the stopper 9, the armature chamber 46 In particular, the fuel in the fuel passage 74 passes through the cylindrical gap 75, the annular groove 76, the plurality of through holes 77, and the spring accommodating chamber 79, and again flows out to the armature chamber 46, so that the fuel in the spring accommodating chamber 79 is increased in pressure. Never happen.

  Accordingly, in the side return type solenoid valve 12 as well, the cylindrical gap 75, the annular groove 76, the plurality of through holes 77 and the spring accommodating chamber 79 can be used as a fuel escape passage, so that the contact surface 66 or stopper of the armature 7 can be used. 9 can be eliminated or reduced. Accordingly, the contact area of the contact portion between the armature 7 and the stopper 9 is increased (enlarged) without deteriorating the operational stability of the armature 7 and without decreasing the electromagnetic force of the electromagnet 6. )be able to. Thereby, it becomes possible to improve the wear resistance of the contact portion between the armature 7 and the stopper 9.

  FIG. 8 shows a fourth embodiment of the present invention and is a view showing an injector solenoid valve.

  The stopper 9 of the solenoid valve 12 of the present embodiment has a flange portion 90 as in the second embodiment. The electromagnetic valve 12 of this embodiment has a fuel discharge passage 91 in addition to the fuel escape passage formed by the cylindrical gap 75, the annular groove 76, the plurality of through holes 77, and the spring accommodating chamber 79. In the fuel discharge passage 91, the armature 7 is pulled upward by the electromagnetic force of the electromagnetic valve 6, and the contact surface 66 of the projection 65 of the armature 7 contacts the regulation surface 72 of the cylindrical wall portion 71 of the stopper 9. At this time, since the fuel in the spring accommodating chamber 79 in the cylindrical wall portion 71 of the stopper 9 flows through the annular gap 94 and the cylindrical gap 93 and flows out to the armature chamber 46, the fuel in the spring accommodating chamber 79 is increased in pressure. There is no. Further, in the present embodiment, the flowability of the fuel in the spring accommodating chamber 79 becomes better than that in the third embodiment, and the rising speed of the armature 7 can be made faster.

[Modification]
In this embodiment, the electromagnet 6 is configured by the coil 13 and the stator 14, but the electromagnet 6 may be configured by only the coil 13. Further, the electromagnet 6 may be configured using another fixed core such as a yoke or a magnetic plate.
In this embodiment, the magnetic pole surface 61 of the stator 14 of the electromagnet 6 and the regulating surface 72 of the cylindrical wall portion 71 of the stopper 9 are installed on the same plane. Alternatively, the restriction surface 72 of the cylindrical wall portion 71 may be protruded to the armature side. In this case, the protrusion 65 of the armature 7 can be eliminated.

  In this embodiment, the electromagnetic actuator for a fuel injection device of the present invention is applied to an electromagnetic actuator for a fuel injection valve, that is, an electromagnetic valve for an injector. The present invention may be applied to an electromagnetic actuator for a fuel injection device that drives not only a moving body such as a shutter but also a moving body such as a shutter and a door at two positions. Further, the position of a moving body such as a valve can be changed continuously or stepwise, such as the solenoid valve (fuel metering valve) 10 of the supply pump 2 or the pressure reducing valve of the common rail 3. You may apply to an electromagnetic flow control valve.

  In this embodiment, the side wall of the stopper is directed from the opening end on the armature side (first end of the stopper 9) toward the opening end on the opposite side in the axial direction (second end of the stopper 9) from the armature side. A cylindrical wall portion 71 extending straight in the axial direction is provided, but as a side wall of the stopper, a cylindrical wall portion (side wall portion) extending from the regulating surface 72 of the stopper 9 to the opposite side in the axial direction with respect to the armature side. It may be provided.

  The annular groove 76 provided on the outer peripheral side of the cylindrical wall portion (side wall) 71 of the stopper 9 communicates with the spring accommodating chamber (space) 79 provided on the inner peripheral side of the cylindrical wall portion (side wall) 71 of the stopper 9. It is sufficient that at least one through hole 77 is provided. In the present embodiment, at least one cylindrical wall portion (side wall) 71 of the stopper 9 is penetrated straight (in a direction substantially perpendicular to the axial direction of the side wall of the stopper 9 (radial direction), radially). Although the above through-holes 77 are provided, the stopper 9 is curved and penetrates in an arc shape or S-shape from the inner peripheral surface of the cylindrical wall portion (side wall) 71 to the outer peripheral side (groove bottom surface of the annular groove 76). As such, at least one or more through holes may be provided.

It is the block diagram which showed the common rail type fuel injection system (Example 1). It is a schematic sectional drawing which showed an injector (Example 1). (A) is sectional drawing which showed the solenoid valve for injectors, (b) is the enlarged view which showed the principal part of (a) (Example 1). (Example 1) which is the top view which showed the armature. (A) is sectional drawing which showed the solenoid valve for injectors, (b) is sectional drawing which showed the principal part of (a) (comparative example 1). (Example 2) which is sectional drawing which showed the solenoid valve for injectors. (Example 3) which is sectional drawing which showed the solenoid valve for injectors. (Example 4) which is sectional drawing which showed the solenoid valve for injectors. It is sectional drawing which showed the injector (prior art). It is sectional drawing which showed the solenoid valve for injectors (prior art). It is sectional drawing which showed the injector (prior art). It is sectional drawing which showed the solenoid valve for injectors (prior art). It is the top view which showed the armature (prior art). It is sectional drawing which showed the solenoid valve for injectors (prior art).

Explanation of symbols

1 Fuel tank (low pressure side of fuel system)
4. Injector (fuel injection valve for internal combustion engine)
5 Valve 6 Electromagnet 7 Armature 9 Stopper 11 Fuel injection nozzle 12 Solenoid valve (solenoid valve for injector)
13 Coil (electromagnet)
14 Stator (electromagnet)
27 Leak port 46 Armature chamber 51 Solenoid valve housing (block)
54 Retaining nut (housing that forms the armature chamber)
62 Stator fitting portion 63 Coil spring 65 Armature projection 66 Armature contact surface 67 Armature fuel escape groove 69 Radial groove of armature 71 Cylindrical wall portion of stopper (side wall of stopper, cylindrical wall portion)
72 Restricting surface of stopper 74 Fuel passage 75 Cylindrical gap 76 Annular groove 77 Through hole 79 Spring accommodating chamber (space in the spring chamber and the cylindrical wall)
119 Leak Port

Claims (12)

(A) an electromagnet that generates magnetic force when energized;
(B) an armature that is attracted to the magnetic pole surface side of the electromagnet by the electromagnetic force of the electromagnet, and (c) disposed inside the electromagnet, and when the armature moves to the magnetic pole surface side of the electromagnet, A stopper having a regulating surface for regulating the movement amount of the armature;
(D) a housing which is disposed so as to surround at least the periphery of the armature and which forms an armature chamber for containing fuel together with the armature between the magnetic pole surface of the electromagnet and the regulating surface of the stopper. In an electromagnetic actuator for a fuel injection device,
A gap communicating with the armature chamber is provided between the electromagnet and the stopper,
The side wall of the stopper is provided with an annular groove that surrounds the outer periphery in the circumferential direction, and a through hole that communicates the space on the inner peripheral side of the side wall of the stopper with the annular groove.
The electromagnetic actuator for a fuel injection device, wherein the through hole communicates with the armature chamber through the annular groove and the gap. The electromagnetic actuator for a fuel injection device according to claim 1,
The electromagnetic actuator for a fuel injection device, wherein the annular groove is recessed from an outer peripheral surface of the side wall of the stopper toward an inner peripheral side of the side wall of the stopper so as to increase a cross-sectional area of the gap. The electromagnetic actuator for a fuel injection device according to claim 1 or 2,
An electromagnetic actuator for a fuel injection device, wherein a groove depth of the annular groove is substantially the same as a passage length of the through hole. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 3,
The electromagnetic actuator for a fuel injection device, wherein the through hole and the annular groove are arranged on the armature side or in the vicinity of the regulation surface with respect to the axial center portion of the side wall of the stopper. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 4,
A is the cross-sectional area of the fuel passage formed between the magnetic pole surface of the electromagnet and the armature, B is the total area of the gap between the electromagnet and the stopper,
When the total area of the through holes is C,
An electromagnetic actuator for a fuel injection device, characterized by satisfying the relationship of A ≦ B and A ≦ C. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 5,
The through hole is composed of a plurality of through holes that penetrate the side wall of the stopper,
The electromagnetic actuator for a fuel injection device, wherein the annular groove is provided so as to connect all of the plurality of through holes. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 6,
The electromagnetic actuator for a fuel injection device, wherein the armature has a radial groove on an end face of the electromagnet including an abutting surface that abuts on the regulating surface. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 7,
A spring for applying a load in a direction to separate the armature from the regulating surface;
An electromagnetic actuator for a fuel injection device, wherein a space on an inner peripheral side of a side wall of the stopper is used as a spring chamber for housing the spring. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 8,
Applied to an injector solenoid valve that injects fuel into a cylinder of an internal combustion engine,
The injector solenoid valve has a leak port that overflows excess fuel to the low pressure side of the fuel system,
The electromagnetic actuator for a fuel injection device, wherein the space on the inner peripheral side of the side wall of the stopper is open toward the leak port on the opposite side to the armature side. The electromagnetic actuator for a fuel injection device according to any one of claims 1 to 8,
Applied to an injector solenoid valve that injects fuel into a cylinder of an internal combustion engine,
The injector solenoid valve has a housing that holds and fixes the opposite end to the armature side of the stopper,
The electromagnetic actuator for a fuel injection device, wherein the space on the inner peripheral side of the side wall of the stopper is liquid-tightly closed by the housing on the opposite side to the armature side. The electromagnetic actuator for a fuel injection device according to claim 9 or 10,
An electromagnetic actuator for a fuel injection device, wherein the armature drives the injector electromagnetic valve to open. The electromagnetic actuator for a fuel injection device according to any one of claims 9 to 11,
The injector solenoid valve has a valve seat in which a valve hole is formed, and a valve that opens and closes the valve hole by being seated on and disengaged from the valve seat.
An electromagnetic actuator for a fuel injection device, wherein the armature drives the valve to open.

Images