JP2004137996A - Hydraulic control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic control valve capable of being highly pressurized and preventing erosion from generating. <P>SOLUTION: The hydraulic control valve is equipped with a valve body 307 having an introduction passage 312 communicating with a high-pressure fluid passage 208 and an exhaust passage 311 communicating with a low-pressure fluid passage 209, a valve part B having a needle 311, a fixed iron core 301 having a housing 302 where an opening part 302a which allows to integrally communicate with the valve body 307 and can operate a needle 313 is formed, and an electromagnetic drive part S having an electromagnetic coil C and a movable member 317. The movable member 317 and a sucking member 303 are disposed in an inner periphery of the opening part 302a, and a fuel passable fuel gallery G is provided on an air gap part B formed between the movable member 317 and the sucking member 303. A fuel groove 303m opening to the outer peripheral edge part is formed on the end surface part of the sucking member 303 forming the air gap part B. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic control valve, and more particularly to a hydraulic control valve used for controlling an injection timing of a fuel injection device that injects high-pressure fuel to a diesel engine.
[0002]
[Prior art]
As a fuel injection device, for example, a distribution type fuel injection pump is known as a fuel injection pump used for a fuel injection device of a diesel engine (Patent Document 1 and the like). In the related art disclosed in Patent Literature 1 and the like, a timer device that controls an injection timing at which fuel is injected into each cylinder of a diesel engine is provided. This timer device changes the phase of the cam movement of the face cam that reciprocates the plunger for feeding the fuel, that is, the advance timing, thereby changing the injection timing of the high-pressure fuel injected into the combustion chamber of the cylinder through the fuel injection valve. Is to adjust. The face cam has a cam profile having a plurality of peaks corresponding to the number of cylinders of the engine, and a cam roller is in rolling contact with the cam profile. When the cam roller comes into contact with the cam profile, the face cam and the plunger reciprocate a plurality of times during one rotation of the drive shaft, that is, a plurality of times according to the number of engine cylinders.
[0003]
The cam roller is supported by a roller ring, and the roller ring is connected via a rod to a timer piston constituting a timer device. The timer piston is housed in a timer pressure chamber formed in the pump housing. When the fuel pressure in the timer pressure chamber is changed by the hydraulic control valve, the timer piston is displaced in the axial direction, and this displacement displaces the roller ring through the rod in the circumferential direction. As a result, the cam roller is displaced in the circumferential direction with respect to the face cam, that is, the advance phase is changed.
[0004]
As a hydraulic control valve used in the timer device for adjusting the injection timing of the high-pressure fuel, there is a hydraulic control valve disclosed in Patent Document 2. The fuel pressure in the timer pressure chamber controlled by the hydraulic control valve becomes a high pressure substantially proportional to the injection pressure because the timer piston receives the reaction force of the face cam during the fuel pumping process by the plunger. In some cases, the fuel pressure in the timer pressure chamber reaches about 10 MPa. For this reason, the hydraulic control valve disclosed in Patent Literature 2 has a shut-off structure in which fuel pressure does not act on the coil unit due to the pressure resistance of the electromagnetic drive unit, particularly the coil unit. In this fuel shutoff structure, the fuel shutoff member reduces the fuel volume around the air gap formed by the stator core as the suction member and the needle as the movable member.
[0005]
[Patent Document 1]
JP-A-63-110640
[0006]
[Patent Document 2]
JP-A-10-121989
[0007]
[Problems to be solved by the invention]
In the conventional hydraulic control valve, since the coil portion has a fuel cutoff structure, a cooling effect due to fuel circulation or the like cannot be expected, so that the internal temperature of the electromagnetic drive unit tends to increase. The increase in the internal temperature further increases the temperature of the fuel in the fuel gallery, and in some cases, erosion may occur on the end faces of the needle and the stator core constituting the air gap.
[0008]
Also, in recent years, due to social demands, the exhaust gas regulations of diesel engines are becoming stricter year by year, and it is desired to increase the pressure of the fuel injection device. The fuel pressure in the timer pressure chamber applied to the hydraulic control valve can be further increased. There is.
[0009]
The present invention has been made in view of such circumstances, and accordingly, has as its object to provide a hydraulic control valve which has a fuel shut-off structure of an electromagnetic drive unit for achieving a high pressure and can prevent the occurrence of erosion. Is to do.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a valve body having an introduction passage communicating with the high-pressure fluid passage and a discharge passage communicating with the low-pressure fluid passage is slidably housed in the valve body. A valve section having a needle that communicates with the discharge passage and can be shut off, and a valve body that is integrally connected to the valve body to receive the needle and to form an opening through which the needle can be operated; Drive unit including a fixed core having a housing in the shape of a stator, an electromagnetic coil housed in the stator core and configured to be liquid-tight with high-pressure fluid, and a movable member movable integrally with the needle. In the hydraulic control valve provided with, the movable member and the suction member of the stator iron core facing in the axial direction are arranged on the inner periphery of the opening, and the inner periphery, the movable member And a fuel gallery portion which is defined by the suction member and which is capable of conducting fuel to an air gap formed between the movable member and the suction member which move in the axial direction by energizing and stopping the energization of the electromagnetic coil. At least one of the end surface of the suction member and the movable member forming the air gap portion is formed with a fuel groove that opens to the outer peripheral edge of the end surface.
[0011]
This makes it possible to suppress the generation of negative pressure, which is a cause of erosion.
[0012]
Generally, in order to improve the responsiveness of the hydraulic control valve, the air gap between the suction member and the movable member of the electromagnetic drive unit is minimized and minimized in consideration of the required flow rate of the high-pressure fluid that is communicated and shut off by the hydraulic control valve. Is planned. In particular, this air gap is minimized when the movable member is sucked by the suction member by the electromagnetic force generated in the electromagnetic coil by energization. In this state, the space formed in the air gap serves as a fuel passage for guiding the fuel and may hinder the flow of the fuel. Further, when the high-pressure fluid to be controlled by the hydraulic control valve is fuel in a timer pressure chamber that is substantially proportional to the fuel injection pressure, such as a hydraulic control valve used in a timer device of a fuel injection device, one fuel injection process is performed. , The pressure of the high-pressure fuel fluctuates. Therefore, a negative pressure is easily generated in the air gap. Further, since the pressure of the high-pressure fuel fluctuates, particularly during a period in which the pressure is low in the course of the fluctuation, there is a high possibility that a negative pressure is generated, that is, a cavity is generated.
[0013]
On the other hand, in the hydraulic control valve of the present invention, since the fuel groove is provided on the end face forming the air gap, even if the amount of the air gap is small, the flow of the fuel guided to the air gap is not obstructed. It is possible to suppress the generation of negative pressure, which is a cause of cavity generation. Therefore, occurrence of erosion can be prevented.
[0014]
According to the second aspect of the present invention, an annular groove facing the fuel groove is formed on the inner peripheral surface near the air gap.
[0015]
Thereby, it is possible to reduce the collapse energy of the cavity formed by the generation of the negative pressure.
[0016]
For example, when a negative pressure is generated in the air gap and a cavity is generated, the air gap expands during the lift and when high-pressure fuel flows easily, an annular groove formed around the air gap is formed. Since the volume of the fuel gallery is increased by the fuel stored in the fuel gallery, it is possible to speed up the mutual flow of the fuel. As a result, the collapse of the cavity can be suppressed and the cavity collapse energy can be reduced. Therefore, occurrence of erosion can be suppressed.
[0017]
According to claim 3 of the present invention, the housing includes a collar portion that is disposed so as to be in contact with the entire circumference of one axial end of the electromagnetic coil, and the collar portion is a part of the inner peripheral surface. Is composed.
[0018]
Thereby, the collar portion can constitute a fuel cutoff structure of the electromagnetic drive unit, particularly the electromagnetic coil.
[0019]
According to the fourth aspect of the present invention, the annular groove is formed on the inner peripheral surface of the collar portion.
[0020]
This makes it possible to suppress the occurrence of erosion without complicating the structure such as adding members as compared with the conventional structure.
[0021]
According to the fifth aspect of the present invention, a valve seat portion is provided on the inner periphery of the valve body which can be brought into contact with or separated from the needle by axial movement of the needle, and the introduction passage communicates with the fuel gallery portion. are doing.
[0022]
As a hydraulic control valve, erosion can be prevented even in a case where the introduction passage through which the high-pressure fluid is introduced and the fuel gallery section are always in communication with each other and are affected by pressure fluctuations of the high-pressure fluid.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
A specific embodiment of the fuel injection device of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating the entire configuration of the hydraulic control valve of the present embodiment. FIG. 2 is a cross-sectional view showing a part of a structure of a main part according to the present embodiment, showing a suction member in FIG. 1, wherein FIG. 2A is a vertical cross-sectional view, and FIG. It is the top view seen from the gap side. FIG. 3 is a schematic sectional view showing a schematic configuration of a distribution type fuel injection device equipped with the hydraulic control valve of the present embodiment. FIG. 4 is a cross-sectional view illustrating a structure of a main part related to the hydraulic control valve of the present invention in the distribution type fuel injection device of FIG.
[0024]
As a hydraulic drive device using the hydraulic control valve of the present invention, there is a fuel injection device 1 as shown in FIG. The fuel injection device 1 includes a drive shaft 101 to which the torque of the engine is transmitted, a pump housing 100, a feed pump 111, a pump chamber 114 formed in the pump housing 100, a plunger 106, a face cam 107 , A timer device 2 having a timer piston 203 and a timer pressure chamber 204, and a hydraulic control valve 3 for controlling the fuel pressure in the timer pressure chamber 204 of the timer device 2. The drive shaft 101 is connected to a crankshaft of the engine, and a rotational force is transmitted in synchronization with the rotation of the diesel engine. More specifically, the drive shaft 101 is driven at a reduced speed of one half of the engine speed. The drive shaft 101 rotates a vane type feed pump 111 provided in the pump housing 100, and the feed pump 111 sucks fuel from a fuel tank. The fuel sucked up by the feed pump 111 is supplied to a pump chamber 114 formed in the pump housing 100 after the pressure is regulated by a pressure regulating valve 111p. More specifically, the pressure regulating valve 111p is disposed between the pump chamber side, that is, the discharge side of the feed pump 111, and the fuel tank side, that is, the low pressure side, and controls the fuel pressure in the pump chamber 114 to the rotation speed of the feed pump 111. The pressure is adjusted to a pressure approximately proportional to or a predetermined pressure. In the present embodiment, the pressure adjusting valve 111p adjusts the fuel pressure in the pump chamber 114 to a substantially predetermined pressure (about 1 MPa in the present embodiment).
[0025]
The feed pump 111 is configured to be rotatable integrally with the drive shaft 101 and is actually provided in a direction perpendicular to the plane of the drawing, but is drawn parallel to the drive shaft 101 for the sake of drawing.
[0026]
Here, the fuel on the side communicating with the fuel tank is low-pressure fuel, and the fuel sucked up by the feed pump 111 and supplied to the pump chamber 114, that is, the fuel in the timer pressure chamber 204 of the timer device 2 described below is referred to as high-pressure fuel. Call. Note that this high-pressure fuel is distinguished from high-pressure fuel (pressurized fuel) that is pressurized by the plunger 106 in order to inject and supply it to the engine via the fuel injection valve 4.
[0027]
Further, as shown in FIG. 3, the drive shaft 101 has a signal rotor 102 mounted coaxially. A plurality of convex teeth are formed on the outer periphery of the signal rotor 102, and a rotation angle sensor 103 opposed thereto generates a pulse signal according to the engine speed by electromagnetic induction of the convex teeth of the signal rotor 102. Then, it outputs to the electronic control device 104. The electronic control device 104 has a drive circuit for driving a spill valve 105 and a hydraulic control valve 3 described later.
[0028]
As shown in FIG. 3, a face cam 107 is connected to the drive shaft 101 via a coupling (not shown) so as to be able to rotate synchronously and to reciprocate in the axial direction. A plunger 106 is connected to one end of the base of the face cam 107 so as to be integrally rotatable. The coupling is a centering device that transmits the rotation of the drive shaft 101 to the plunger 1062 and allows the plunger 106 to freely move in the axial direction.
[0029]
As shown in FIG. 3, the face cam 107 has a cam profile 107a having a plurality of peaks in the circumferential direction corresponding to the number of cylinders of the engine on a surface opposite to a surface to which the plunger 106 is connected. I have. A cam roller 110 is in rolling contact with the cam profile 107a. The face cam 107 and the plunger 106 reciprocate a plurality of times during one rotation of the drive shaft 101, that is, a plurality of times according to the number of cylinders of the engine, by the cam cam roller 110 rolling contact with the cam profile 107a. Note that the cam profile 107a is preferably set to a shape that can obtain an optimum fuel injection pressure or the like in order to adapt a desired engine performance.
[0030]
During the suction stroke of the plunger 106, the plunger 106 moves to the left in the axial direction in FIG. At this time, when one of the suction grooves 106a formed on the peripheral surface of the distal end portion of the plunger 106 communicates with the suction port 112a, the fuel in the pump chamber 114 is sucked into the pressure feeding chamber 113 formed at the distal end of the plunger 106. .
[0031]
During the compression stroke of the plunger 106, the plunger 106 moves to the right in the axial direction in FIG. When the fuel in the pumping chamber 113 is pressurized, the pressurized fuel is guided to a vertical hole 106b formed inside the plunger 106. At this time, the plunger 106 is rotating and is in sliding contact with the cylinder 112 formed in the pump housing 100. By the rotation of the plunger 106, the supply port 106c opened on the outer peripheral surface of the plunger 106 communicates with one of the plurality of discharge ports 112b opened on the inner peripheral surface of the cylinder 112, so that the pressurized fuel is injected. The fuel is supplied from the passage 115a to the fuel injection valve 4 via the delivery valve 115b.
[0032]
A spill valve 105 for releasing the pressure of the pressurized fuel in the pumping chamber 113 is provided in the dismount 115 of the fuel injection device 1. As shown in FIG. 3, in addition to the output signal from the rotation angle sensor 103, the electronic control device 104 includes a top dead center signal (TDC signal) 104a from the engine and an accelerator indicating the magnitude of the engine load. An opening signal 104c, a water temperature signal 104b from a water temperature sensor for detecting a cooling water temperature and the like are input, and fuel injection control is performed based on these signals.
[0033]
Next, the timer device 2 shown in FIGS. 2 and 3 will be described below. A cam roller 110 to which the face cam 107 is connected is supported by a roller ring 109. The roller ring 109 is connected to a timer piston 203 via a rod (slide pin) 201. The timer piston 203 is housed in a timer pressure chamber 204 formed in the pump housing 100, and the fuel in the pump chamber 114 is introduced into the timer pressure chamber 204. Note that the cylindrical outer peripheral surface 109a of the roller ring 109 is rotatable within a predetermined angle range around the axis of the drive shaft 101. The rotation allows the position of the cam roller 110 to move in the rotation direction.
[0034]
The timer pressure chamber 204 is connected to the hydraulic control valve 3 via a fuel passage 208 described later. When the fuel pressure in the timer pressure chamber 204 changes by opening and closing the hydraulic control valve 3, the timer piston 203 is displaced in the axial direction, and this displacement causes the roller ring 109 to rotate in the circumferential direction via the rod 201. As a result, the cam roller 110 is displaced in the circumferential direction relatively to the face cam 107, so that the timing at which the peak of the face cam 9 rides on the cam roller 110, that is, the advance (hereinafter referred to as timer advance) phase changes. Therefore, the fuel injection timing can be changed. The details of the structural relationship between the hydraulic control valve 3 and the timer device 2 will be described later.
[0035]
In FIG. 3, the drive shaft 101 and the timer piston 203 are drawn in parallel for the sake of drawing, but the timer piston 203 actually intersects the drive shaft 101 at right angles.
[0036]
Here, the relationship between the timer device 2 and the hydraulic control valve 3 will be described with reference to FIG. 4, a timer pressure chamber 204 above a timer piston 203 communicates with a pump chamber 114 (see FIG. 3) via a throttle 203a and a check valve 205 provided in the timer piston 203. The fuel pressure in the timer pressure chamber 204 pushes the timer piston 203 downward in the figure, and a timer spring 207 is mounted in the timer low pressure chamber 206 below the timer piston 203 in opposition thereto. The timer low-pressure chamber 206 communicates with the suction port 116 (see FIG. 3) of the feed pump 111, and the pressure is always low during operation. Since the fuel pressure of the pump chamber 114 is introduced into the timer pressure chamber 204, the timer piston 203 moves to a position where the pressing force for pressing the timer piston 203 by the fuel pressure and the urging force of the timer spring 207 are balanced. The timer advance, that is, the injection timing is determined.
[0037]
During the pressure feeding process of the plunger 106, the timer piston 203 receives the pressure feeding reaction force upward through the rod 201 by the pressure reaction force received by the face cam 107, so that the timer high pressure chamber 204 is temporarily Reach about 100 atmospheres.
[0038]
The pump housing 100 is provided with a fuel passage 208 as a high-pressure fluid passage communicating with the timer high-pressure chamber 204 and a fuel passage 209 as a low-pressure fluid passage communicating with the timer low-pressure chamber 207. These fuel passages 208 and 209 are connected via the hydraulic control valve 3. The hydraulic control valve 3 is fixed to the pump housing 100 by a flange 210 and a bolt 211. The hydraulic control valve 3 is electrically connected to an electronic control device 104 that outputs an opening / closing signal that is a control signal for the injection timing. The opening and closing of the hydraulic control valve 3 is controlled by the electronic control device 104 (duty ratio control in the present embodiment). The hydraulic control valve 3 guides a part of the fuel in the timer pressure chamber 204 to the timer low pressure chamber 206 according to the opening / closing ratio according to the duty ratio. That is, the hydraulic pressure in the timer high-pressure chamber 204 is partially released to the timer low-pressure chamber 206 side to be adjusted, and the position of the timer piston 203 and the rotational position of the roller ring 109 are changed. Thereby, the injection timing is controlled.
[0039]
Here, the hydraulic control valve 3 will be described below with reference to FIGS. As shown in FIG. 1, the hydraulic control valve 3 has a valve body 307 having an introduction passage 312 communicating with the high-pressure fluid passage 208 and a discharge passage 311 communicating with the low-pressure fluid passage 209, and sliding inside the valve body 307. A valve portion B, which is movably accommodated and communicates with the introduction passage 307 and the discharge passage 311 and has a shuttable needle 313, is integrally connected with the valve body 307 to accommodate the needle 313. At the same time, a fixed core 301 having a substantially cylindrical housing 302 in which an opening 302a capable of operating the needle 313 is formed, and is housed in the stator core 301 and is liquid-tight with respect to a high-pressure fluid. The electromagnetic drive section S includes an electromagnetic coil C and a movable member 317 that can move integrally with the needle. If the valve portion B has a valve portion structure in which the valve body 307 and the needle 313 move relatively in the axial direction, the communication between the introduction passage 312 and the discharge passage 311 formed in the valve body 307 is communicated and cut off. Any valve part may be used. In the present embodiment, as shown in FIG. 1, the needle 313 movable in the axial direction comes into contact with and separates from the valve seat portion 311 a formed in the valve body 307, so that the introduction passage 312 and the discharge passage 312 are formed. A structure for communicating and blocking the communication of 311 will be described below.
[0040]
A substantially cylindrical housing 302 constituting a part of the stator core 301 has a substantially cylindrical suction member 303 coaxially arranged with a smaller diameter than the housing 302. The suction member (hereinafter, referred to as a stator core) 303 forms a stator core together with the housing 302. An inner space 306 is formed in the center of the stator core 303, and a spring 305 described later is provided in the inner space 306 to form a spring chamber 306.
[0041]
In the housing 302, a valve body 307 having a circular cross section and a substantially annular shim 308 are arranged in this order coaxially from the left side in FIG. The valve body 307 and the shim 308 are positioned by a stepped portion 302 c formed on the inner peripheral surface of the housing 302 by the shim 308, and the valve body 307 is fixed by caulking at a left edge 301 b of the housing 302.
[0042]
The valve body 307 has a through hole 309 that is sufficiently larger than the inner diameter of the shim 308 along the axial direction. The through hole 309 constitutes a valve cylinder 310 that accommodates the needle 313 slidably except for a small diameter portion 311 at the left end in the figure. The small diameter portion 311 of the through hole 309 forms a low pressure side passage as a discharge passage. The discharge passage 311 communicates with a fuel passage 209 communicating with the timer low-pressure chamber 206 (see FIG. 4). On the side wall of the valve body 307, an introduction passage 312 communicating with the fuel flow path 208 communicating with the timer high-pressure chamber 204 is formed, and opens to the inner peripheral surface 310a of the valve cylinder 310. On the inner peripheral surface 310a of the valve cylinder 310, an annular concave portion 310b is formed at an opening position of the introduction hole 312. A valve needle 313 is inserted into the valve cylinder 310. The needle 313 is formed in a substantially rod-shaped member, and a constricted portion 313b at a position facing the shim 308 is constricted.
[0043]
An end edge 314 of the distal end of the needle 313 is formed into a conical surface, and forms a seal portion that can be brought into contact with or separated from the valve seat 311a of the valve 307. Since the concave portion 310b is formed in the inner peripheral surface 310a of the valve cylinder 310, high-pressure fuel is supplied from the timer pressure chamber 204 (see FIG. 3) to the space surrounding the needle 313. In the discharge passage 311, the stepped position of the concave portion 310 b in the inner peripheral surface 310 a of the valve cylinder 310 is an open end, and the open end 311 a is formed into a conical surface whose diameter is reduced on the left side in the figure. The receiving valve seat 311a is formed.
[0044]
The needle 313 has the same cross-sectional shape as the valve cylinder 310 except for the constricted portion 313b, and is formed so as to fold against the inner peripheral surface 310a of the valve cylinder 310. In the needle 313, a portion 313c protruding from the shim 308 toward the spring chamber 306 is press-fitted into a substantially bottomed cylindrical movable member (hereinafter referred to as an armature) 317, and is integrally connected.
[0045]
The armature 317 faces the stator core 303 with an interval (air gap) B. A spring 305 is provided in a spring chamber 306 of the stator core 303, and the spring 305 applies an urging force to the armature 317 in the left direction in the figure.
[0046]
An electromagnetic coil C is arranged between the housing 302 and the stator core 303 coaxially with them. The electromagnetic coil C includes a coil bobbin 318 and a coil 319, and the coil 319 is wound around the coil bobbin 318. When the coil 319 is energized by the electronic control unit 104 (see FIG. 3) via the terminal 320, an electromagnetic force is generated in the electromagnetic coil C. By this electromagnetic force, a suction force for sucking the armature 317 rightward in the drawing is applied to the stator core 303.
[0047]
The operation of the hydraulic control valve 3 will be described together with the operation of the fuel injection device 1. A pulse-like opening / closing control signal is input to the coil 319 of the hydraulic control valve 3. That is, when the coil 319 is not energized, the tip 314 of the needle 313 is in close contact with the valve seat 311a, and the hydraulic control valve 3 is closed as shown in FIG. The communication between the low pressure chambers 206 is shut off. On the other hand, when the coil 319 is energized, the armature 317 is attracted by the stator core 302 and moves rightward in the drawing against the spring force of the spring 305. Then, the seal portion 314 of the needle 313 integrally connected to the armature 317 is separated from the valve seat 311a of the valve body 307, the hydraulic control valve 3 is opened, and the timer pressure chamber 204 and the timer low pressure chamber are opened. 206 communicates.
[0048]
The electronic control device 104 sets the opening and closing ratio of the hydraulic control valve 3 as a duty ratio according to the command value of the fuel injection timing. By optimizing the duty ratio, the timer piston 203 stops at a position where the pressures applied to the upper and lower end surfaces (see FIG. 4) are balanced. Note that the angle is retarded as the duty ratio increases. The hydraulic control valve 3 is normally closed (normally closed) as shown in FIG. 1 in consideration of the case where the coil 319 or the like fails, so that the fuel injection timing is advanced most in this case.
[0049]
Here, the hydraulic control valve 3 of the present embodiment has the following features.
[0050]
As shown in FIG. 1, the electromagnetic coil C is accommodated in a housing 302 and a collar portion 302c which is a part of the housing 302. Further, a shaft end 318a of the coil bobbin 318 is provided over the entire periphery of the collar portion 302c. The space R defined by the housing 302, the collar portion 302c, and the coil bobbin 318 of the electromagnetic coil C is filled with a resin having relatively high heat resistance so as to keep the inside airtight. Note that the collar portion 302c and the housing 302 constitute a fuel cutoff structure for making the electromagnetic coil C airtight.
[0051]
Further, in the present embodiment, as shown in FIG. 1, an armature 317 and a stator core 303 are arranged in an opening 302a (more specifically, a collar portion 302c) of the housing 302 in which a needle 313 can be operated. A fuel gallery G is formed in a space defined by the inner periphery of the portion 302c, the armature 317, and the stator core 303. The fuel of the fuel gallery G is arranged in such a positional relationship that the fuel can be introduced into the air gap B formed by the armature 317 and the end face of the stator core 303. The air gap B is set to be larger than the gap A between the needle 313 and the shim 308 shown in FIG. (Gap A <B). The fuel gallery G communicates with the introduction passage 312 via a gap between a sliding portion of the valve cylinder 310 and the needle 313.
[0052]
Generally, in order to improve the responsiveness of the hydraulic control valve, the required air flow of the high-pressure fluid to be communicated and cut off by the hydraulic control valve is taken into consideration, and the air gap A between the stator core 303 of the electromagnetic drive unit S and the armature 317 is reduced as much as possible. Minimization is attempted. In particular, the air gap A is minimized when the armature 317 is attracted to the stator core 303 by the electromagnetic force generated in the electromagnetic coil C by energization. In this state, the space formed in the air gap B serves as a fuel passage for guiding the fuel, and may obstruct the flow of the fuel. Further, when the high-pressure fluid to be controlled by the hydraulic control valve is the fuel in the timer pressure chamber 204 that is substantially proportional to the fuel injection pressure in the timer device 2 of the fuel injection device 1, the high-pressure fuel in one fuel injection process Pressure fluctuates. Therefore, a negative pressure is easily generated in the air gap portion A. Further, since the pressure of the high-pressure fuel fluctuates, particularly during a period in which the pressure is low in the course of the fluctuation, there is a high possibility that a negative pressure is generated, that is, a cavity is generated.
[0053]
On the other hand, in the present embodiment, the inside and outside of the stator core 303 can be connected to at least one end face (the end face of the stator core 303 in the present embodiment) of the stator core 303 and the armature 317 forming the air gap portion B. A groove (hereinafter referred to as a fuel groove) 303m is provided (see FIGS. 1 and 2). More specifically, a fuel groove 303m is formed on the end face of the stator core 303 so as to open at the outer peripheral edge of the end face of the stator core 303.
[0054]
Thus, since the fuel groove 303m is provided on the end face forming the air gap B, it is possible to prevent the flow of the fuel guided to the air gap B even with a small air gap amount. In addition, it is possible to suppress the generation of negative pressure, which is a cause of cavity generation. Therefore, occurrence of erosion can be prevented.
[0055]
Further, in this embodiment, an annular concave portion (hereinafter, referred to as an annular groove) 302m is formed on the inner peripheral surface of the collar portion 302c. Specifically, an annular groove 302m is formed radially outward facing the fuel groove 303m.
[0056]
Thereby, it is possible to reduce the collapse energy of the cavity formed by the generation of the negative pressure. For example, when a negative pressure is generated in the air gap portion B and a cavity is generated, the air gap B expands during the lift, and when the high pressure fuel flows easily, the air gap B is formed around the air gap portion B. The volume of the fuel gallery B can be increased by the fuel stored in the annular groove 302m. For this reason, it is possible to speed up the mutual flow of the fuel. As a result, the collapse of the cavity can be suppressed and the cavity collapse energy can be reduced. Therefore, occurrence of erosion can be suppressed.
[0057]
As shown in FIG. 2, it is preferable that a plurality of fuel grooves 303m (four in the present embodiment) are arranged so as to face the annular groove 302m. Accordingly, the fuel flow can be further accelerated to a plurality of fuel grooves 303m by dispersing the fuel flow into a plurality of fuel grooves as compared to a single fuel groove.
[0058]
In addition, at least one of the stator core 303 and the armature 317 has an end face where the fuel groove 303m is formed, as shown in FIG. ing. It is preferable that the fuel groove 303m that can communicate between the inside and the outside of the stator core 303 described above communicates with the spring chamber as shown in FIGS.
[0059]
Furthermore, in the present embodiment, it is only necessary to form the annular groove 302m on the inner peripheral surface of the collar portion 302c constituting the fuel cutoff structure related to the electromagnetic coil C. Erosion can be suppressed without complicating the structure such as adding members as compared with the conventional structure.
[0060]
In the above-described embodiment, the hydraulic control valve 3 is provided with a fuel groove 303m on at least one of the end faces (the end face of the stator core 303 in this embodiment) of the stator core 303 and the armature 317 forming the air gap portion B. With the provision, it is possible to suppress the generation of a negative pressure, which is a factor of generating a cavity, and thus it is possible to prevent the occurrence of erosion caused by the energy accompanying the generation and collapse of the cavity. In addition, since the annular groove 302m is formed in the inner peripheral surface near the air gap portion B (in the present embodiment, the inner peripheral surface of the collar portion 302c), even if the air gap portion B generates a negative pressure, the cavity is formed. Even if erosion occurs, the collapse of the cavity can be suppressed, so that erosion due to the cavity collapse energy can be suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an entire configuration of a hydraulic control valve according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a part of a structure of a main part according to the first embodiment and illustrating a suction member in FIG. 1; FIG. 2 (a) is a vertical cross-sectional view, and FIG. FIG. 3 is a plan view seen from the air gap side.
FIG. 3 is a schematic cross-sectional view showing a schematic configuration of a distribution type fuel injection device equipped with the hydraulic control valve of the present embodiment.
FIG. 4 is a cross-sectional view illustrating a structure of a main part related to a hydraulic control valve of the present invention in the distribution type fuel injection device of FIG.
[Explanation of symbols]
1 fuel injection device
2 Timer device
203 timer piston
204 Timer pressure chamber
208 Fuel passage (high-pressure fluid passage)
209 Fuel flow path (low-pressure fluid path)
3 Hydraulic control valve
301 Stator core
302 housing
302a opening
302c color part
302m annular groove
303 Stator core (suction member)
303m fuel groove
310 valve cylinder
311 discharge passage
312 Introductory passage
311a Valve seat
317 armature (movable member)
318 Coil bobbin
318a Shaft end
B Air gap
G fuel gallery

Claims (5)

A valve body having an introduction passage communicating with the high-pressure fluid passage, and a discharge passage communicating with the low-pressure fluid passage; and a slidably housed inside the valve body, capable of communicating and blocking communication between the introduction passage and the discharge passage. A valve portion having a unique needle;
A fixed core having a substantially cylindrical housing formed with an opening through which the needle can be operated, while being integrally connected to the valve body, and housed in the stator core, In a hydraulic control valve including an electromagnetic drive unit having an electromagnetic coil configured to be liquid-tight to a high-pressure fluid and a movable member that can move integrally with the needle,
On the inner periphery of the opening, a suction member of a stator core facing the movable member and the axial direction is arranged,
An air gap formed between the movable member and the suction member, which is partitioned into the inner periphery, the movable member, and the suction member, and which moves forward and backward in the axial direction by energizing the electromagnetic coil and stopping energization. A fuel gallery part capable of conducting fuel is provided,
A hydraulic control valve, characterized in that at least one of an end surface of the suction member and the movable member forming the air gap portion is formed with a fuel groove that is open at an outer peripheral edge of the end surface. The hydraulic control valve according to claim 1, wherein an annular groove facing the fuel groove is formed on a surface of the inner periphery near the air gap. The housing includes a collar portion disposed so as to be in contact with the entire circumference of one shaft end of the electromagnetic coil,
The hydraulic control valve according to claim 1, wherein the collar portion forms a part of the inner peripheral surface. The hydraulic control valve according to claim 3, wherein the annular groove is formed on an inner peripheral surface of the collar portion. An inner periphery of the valve body is provided with a valve seat that can be brought into contact with and separated from the needle by axial movement thereof,
The hydraulic control valve according to any one of claims 1 to 4, wherein the introduction passage communicates with the fuel gallery.

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