JP2007278303A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve wherein an anchor portion of a valve element is easily molded and machined in such a manner that a change in the outer diameter of the anchor portion is suppressed to improve responsiveness and assembling workability. <P>SOLUTION: The valve element 13 is provided in a magnetic cylinder body 2 of the fuel injection valve in a slidably displaceable manner. It consists of a spherical valve portion 14 to be seated on or off a valve seat 11B of a valve seat member 11, and the cylindrical anchor portion 15 having a lower end fixed to the valve portion 14 and an upper end opposed to a small diameter sleeve portion 10B of a core cylinder 10. The anchor portion 15 is formed by using a means such as a MIM technique for injection molding metal powder of a magnetic material and sintering it so that its relative density is within a range of 95-98%. On the end face of an attracting part 15A of the anchor portion 15, a close contact preventing recessed groove 16 is formed with pressing work for preventing the close contact of the anchor portion 15 with the small diameter sleeve portion 10B of the core cylinder 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection valve suitably used for injecting fuel into, for example, an automobile engine.

  In general, a fuel injection valve used in an automobile engine or the like is configured to displace fuel supplied to a fuel passage in the casing by displacing a valve body that is displaceable in the casing by an actuator such as an electromagnetic coil. It is injected toward the combustion chamber of the engine. A prior art fuel injection valve having such a configuration is known, for example, from Japanese Patent Application Laid-Open No. H10-228707.

JP 2000-8990 A

  A fuel injection valve according to this type of prior art is provided with a magnetic cylinder formed in a cylindrical shape by a magnetic material and having a fuel passage inside, and a cylindrical shape formed by a magnetic material and inserted into the magnetic cylinder. A core cylinder, a valve seat member positioned downstream of the core cylinder and provided in the magnetic cylinder and surrounding the injection port to form a valve seat, and between the core cylinder and the valve seat member A valve body that is slidably displaced in the magnetic cylinder body and is seated on and off the valve seat of the valve seat member, and is inserted into the core cylinder to urge the valve body in the valve closing direction. A valve spring provided between the spring receiver and the valve body, a yoke made of a magnetic material provided on the outer peripheral side of the magnetic cylinder, and provided between the yoke on the outer peripheral side of the magnetic cylinder. The electromagnetic coil is generally constituted.

  The electromagnetic coil constitutes an electromagnetic actuator together with the magnetic cylinder, the core cylinder and the yoke, and resists the valve spring by forming a closed magnetic path through the core cylinder, the valve element and the yoke when energized from the outside. The valve body is separated from the valve seat of the valve seat member.

  Here, the valve body is provided by being fixed to a cylindrical anchor portion extending in the axial direction in the magnetic cylinder and having an upstream end facing the core cylinder and a downstream end of the anchor portion. And a spherical valve portion that is separated from and seated on the valve seat member. Then, the anchor part of the valve body is formed by forming a cylindrical body made of a magnetic material into a required shape using means such as cold forging and cutting, and then performing finish processing such as end face grinding and deburring processing. ing.

  Further, when the end surface of the anchor portion facing the core cylinder is a flat surface, when the end surface of the anchor section comes into contact with the end surface of the core cylinder by opening the valve body, the anchor section is interposed between the two. Due to the viscosity of the fuel, etc., the anchor part sticks to the core cylinder, and due to this adhesion phenomenon, the valve closing operation of the valve element is delayed, and the responsiveness when the valve element opens and closes may be reduced. There is.

  For this reason, the end face of the anchor part facing the core cylinder is pressed to form a concave groove for preventing adhesion, and the anchor part of the valve body is in close contact with the end face of the core cylinder. This is prevented by a concave groove.

  However, since the fuel injection valve according to the above-described prior art is formed by using means such as cold forging and cutting for the anchor portion of the valve body, a concave groove for preventing adhesion is pressed on the end surface of the anchor portion. When this occurs, there is a problem in that the meat of the portion crushed by the press escapes to the inside and outside diameter sides of the anchor portion, and the outside diameter dimension of the anchor portion changes.

  And since the outer diameter (outer peripheral surface) of the anchor portion functions as a sliding surface with respect to the magnetic cylindrical body, when the outer diameter of the anchor portion changes, the anchor portion is inserted into the inner periphery of the magnetic cylindrical body. This causes a problem that it becomes difficult to increase the sliding resistance between the two and causes the responsiveness of the valve body to deteriorate.

  On the other hand, in the prior art, in order to solve such a problem, after the concave groove for preventing adhesion is pressed on the end face of the anchor portion, finishing grinding may be performed again on the outer peripheral surface of the anchor portion. . However, in this case, the number of finishing processes increases, and there is a problem that workability at the time of production and assembly is lowered.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to easily mold and process the anchor portion of the valve body, and to prevent the outer diameter of the anchor portion from changing. It is an object of the present invention to provide a fuel injection valve that can improve responsiveness, assembly workability, and the like.

  In order to solve the above-described problems, the invention of claim 1 is directed to a valve body of a fuel injection valve, a cylindrical anchor portion extending in an axial direction in a magnetic cylinder and having an upstream end facing the core cylinder, The anchor portion is provided at a downstream end portion of the anchor portion and is configured to be attached to and detached from the valve seat of the valve seat member. The anchor portion is formed by injection molding a metal powder made of a magnetic material and has a relative density of 95 to 98. % Is formed by sintering so that the anchor portion is provided with an adhesion prevention groove on the upstream end face of the anchor portion to prevent the anchor portion from sticking to the core tube.

  According to the invention of claim 2, the adhesion preventing groove is formed by press forming a plurality of concave grooves on the end face of the anchor portion.

  According to the invention of claim 3, the adhesion preventing groove is constituted by a plurality of concave grooves formed radially on the end face of the anchor portion.

  With this configuration, in the invention of claim 1, the anchor portion of the valve body can be formed by using a metal injection molding means called a so-called MIM method (metal injection molding), and the metal structure of the anchor portion has a relative density. Is 95 to 98%, and the remaining 2 to 5% are fine independent holes formed in the anchor portion. For this reason, even if the adhesion prevention groove is formed in the end face of the anchor portion by press working or the like, the holes crushed by the press can absorb the escape to the inner and outer diameter sides of the anchor portion by the holes, and the anchor The outer diameter of the part will not change.

  Therefore, when the valve body formed in this way is assembled in the magnetic cylinder so as to be slidable, the sliding resistance between the valve body and the magnetic cylinder can be kept small, Responsiveness when the valve is closed can be improved. In addition, it is not necessary to re-finish grinding on the outer peripheral surface of the anchor part after pressing the anti-adhesion groove on the end face of the anchor part as in the prior art, so that the number of finishing processes can be surely reduced. Therefore, workability in manufacturing and assembling the valve body of the fuel injection valve can be improved.

  According to the invention of claim 2, the adhesion preventing groove is formed by press forming a plurality of concave grooves on the end face of the anchor portion. As a result, a plurality of press-molded concave grooves can be formed on the end surface of the anchor portion, and the end surfaces of the anchor portion can be prevented from sticking to the core tube by the concave grooves. .

  According to the invention of claim 3, the adhesion preventing groove is constituted by a plurality of concave grooves formed radially on the end face of the anchor portion. Thereby, the several recessed groove | channel extended radially can be formed in the end surface of an anchor part, and it can prevent favorably that the end surface of an anchor part adheres to a core cylinder.

  Hereinafter, a fuel injection valve according to an embodiment of the present invention will be described in detail with reference to FIGS.

  Reference numeral 1 denotes a valve casing that forms the outer shell of the fuel injection valve. The valve casing 1 includes a magnetic cylinder 2, a yoke 5, a resin cover 8, and the like, which will be described later.

  Reference numeral 2 denotes a stepped cylindrical magnetic cylinder constituting the main body of the valve casing 1, and the magnetic cylinder 2 is formed as a thin metal pipe having a stepped shape using, for example, a stainless steel material having magnetism. ing. In the magnetic cylinder 2, one side portion in the axial direction becomes the large-diameter portion 2A, the intermediate portion in the axial direction becomes the medium-diameter portion 2B having a smaller diameter than the large-diameter portion 2A, and the other side portion in the axial direction becomes It is formed as a stepped cylinder that becomes a small-diameter portion 2C having a smaller diameter than the medium-diameter portion 2B.

  In addition, the magnetic cylinder 2 is formed with a flange portion 2D that protrudes outward in the radial direction on one end side of the large-diameter portion 2A. The large-diameter portion 2A is provided with a fuel filter 4 to be described later on the inner peripheral side thereof, and provided with a resin cover 8 to be described later that constitutes the valve casing 1 on the outer peripheral side.

  Reference numeral 3 denotes a fuel passage provided in the magnetic cylinder 2, and the fuel passage 3 serves as a flow passage for fuel supplied from, for example, a fuel pump via a fuel supply pipe (both not shown). . In the fuel passage 3, one end of the large-diameter portion 2 </ b> A of the magnetic cylindrical body 2 serves as an inflow port, and extends in the axial direction from the inflow port to the position of the valve seat member 11.

  Reference numeral 4 denotes a fuel filter that is inserted into the inflow side of the large-diameter portion 2A of the magnetic cylinder 2 by press-fitting means. The fuel filter 4 filters and cleans the fuel supplied to the fuel passage 3. is there.

  A yoke 5 provided on the outer peripheral side of the magnetic cylinder 2 is formed in a stepped cylinder using, for example, a magnetic metal material, and constitutes the valve casing 1 together with the magnetic cylinder 2 and the like. is there. As shown in FIG. 2, the yoke 5 is formed by reducing the diameter of the enlarged diameter cylindrical portion 5A provided to cover a later-described electromagnetic coil 7 from the outer peripheral side and the other end side of the enlarged diameter cylindrical portion 5A. It is comprised from the diameter-reduced cylinder part 5B press-fit by the outer peripheral side of the small diameter part 2C of the magnetic cylinder 2. As shown in FIG.

  Reference numeral 6 denotes a connecting core provided between the enlarged diameter cylindrical portion 5A of the yoke 5 and the intermediate diameter portion 2B of the magnetic cylindrical body 2. The connecting core 6 is substantially made of the same magnetic metal material as that of the yoke 5. It is formed in a C shape and is provided so as to surround the medium diameter part 2B of the magnetic cylinder 2 from the outside.

  7 is an electromagnetic coil provided on the outer peripheral side of the medium diameter portion 2B of the magnetic cylindrical body 2 and between the enlarged diameter cylindrical portion 5A of the yoke 5, and the electromagnetic coil 7 includes the magnetic cylindrical body 2, the yoke 5 and a later-described electromagnetic coil. The electromagnetic actuator is configured together with the core cylinder 10. The electromagnetic coil 7 is energized when energized from the outside using a connector 9 to be described later, and the closed magnetic path H as shown by a dotted line in FIG. 2 is connected to the yoke 5, the small diameter portion 2C of the magnetic cylinder 2, the core. It forms through the cylinder 10, the anchor part 15 of the valve body 13 mentioned later, the connection core 6, etc.

  8 is a resin cover provided on the outer peripheral side of the large-diameter portion 2A of the magnetic cylinder 2, and the resin cover 8 is assembled with the yoke 5, the connecting core 6, the electromagnetic coil 7 and the like on the outer peripheral side of the magnetic cylinder 2. In this state, the insulating resin material is formed by injection molding in a mold (not shown). A connector 9 for feeding power to the electromagnetic coil 7 is integrally formed on the resin cover 8.

  Reference numeral 10 denotes a core cylinder that is press-fitted inside the magnetic cylinder 2. The core cylinder 10 is formed in a stepped cylinder by, for example, a magnetic metal material or the like. 5 and a closed magnetic path H by the electromagnetic coil 7 is formed as shown by a dotted line in FIG. As a result, the core cylinder 10 magnetically attracts a suction portion 15A of the anchor portion 15 described later against the spring force of the valve spring 18, and the valve portion 14 of the valve body 13 from the valve seat 11B of the valve seat member 11. It is intended to be separated.

  Here, the core cylinder 10 has a large-diameter press-fit portion 10A that is press-fitted into the medium-diameter portion 2B of the magnetic cylinder 2, and extends in the axial direction from the large-diameter press-fit portion 10A into the small-diameter portion 2C. The small-diameter sleeve portion 10B is inserted into the 2C in a loosely fitted state with a gap.

  Further, the core cylinder 10 has a large diameter press-fit portion 10A that is press-fitted into the medium-diameter portion 2B, so that the tip surface of the small-diameter sleeve portion 10B is attached to the end surface of the suction portion 15A of the anchor portion 15 described later on the shaft shown in FIG. Opposite the gap S in the direction. And the core cylinder 10 regulates the lift amount (valve opening degree) of the valve body 13 by the clearance S in the axial direction.

  Reference numeral 11 denotes a cylindrical valve seat member located in the downstream side of the core cylinder 10 and provided in the small diameter portion 2C of the magnetic cylinder 2. The valve seat member 11 has a fuel passage 3 as shown in FIG. There are provided an injection port 11A for injecting the fuel inside, and a valve seat 11B that surrounds the injection port 11A and is formed in a funnel shape (tapered shape) and through which the fuel flows.

  A nozzle plate 12 is provided so as to cover the injection port 11A of the valve seat member 11, and the nozzle plate 12 is fixed to the front end surface of the valve seat member 11 by welding means as shown in FIG. In the nozzle plate 12, a plurality of nozzle holes 12 </ b> A are formed at positions that communicate with the injection ports 11 </ b> A of the valve seat member 11.

  13 is a valve body which is located between the core cylinder 10 and the valve seat member 11 and is displaceably provided in the small diameter portion 2C of the magnetic cylinder 2. The valve body 13 includes an anchor portion 15 which will be described later, It is constituted by a spherical valve portion 14 provided at the downstream end portion of the anchor portion 15 and seated on and off from the valve seat 11B of the valve seat member 11.

  Reference numeral 15 denotes an anchor portion that constitutes the valve body 13 together with the valve portion 14, and the anchor portion 15 is located on the upstream side (one axial direction) as shown in FIGS. 2 and 3, and the small-diameter sleeve portion 10 </ b> B of the core cylinder 10. And a large-diameter suction portion 15A that is opposed to the core cylinder 10 in the axial direction, and that extends from the suction portion 15A toward the other side (downstream side) in the axial direction. And a small-diameter shaft portion 15B fixed using

  In this case, the anchor portion 15 is formed as a stepped cylindrical body extending in the axial direction by a magnetic metal material using means such as an MIM method described later. That is, the anchor portion 15 is formed by injection molding a metal powder made of a magnetic material using a mold (not shown) by the MIM method shown in FIG. 4 to be described later, and then an anchor molded body 21 to be described later shown in FIG. It is formed by sintering so that the relative density of the metal structure is in the range of 95 to 98%.

  The suction portion 15A of the anchor portion 15 has a sliding surface portion 15C formed on the outer peripheral surface thereof as a small annular step portion extending over the entire circumference, and the anchor portion 15 is formed on the inner peripheral surface of the small diameter portion 2C by the sliding surface portion 15C. Slidably touching. Further, as shown in FIGS. 6 to 8, the upstream end (one side) end face of the suction portion 15A has an annular convex portion 15D at the radially inner portion and an annular relief surface portion 15E at the radially outer portion.

  Here, the annular relief surface portion 15E surrounds the annular convex portion 15D from the outside in the radial direction, and the height position thereof substantially corresponds to the bottom surface of the concave groove 16 described later. The annular relief surface portion 15E is formed by press-molding the annular convex portion 15D so that the annular convex portion 15D side of the anchor portion 15 abuts against the end surface of the small diameter sleeve portion 10B of the core cylinder 10 when the valve body 13 is opened. This is to prevent together with the recessed groove 16 formed.

  Further, a spring accommodating portion 15F is formed inside the adsorption portion 15A, and a later-described valve spring 18 is disposed in the spring accommodating portion 15F. On the other hand, a pair of oil passage holes 15G (only one is shown) is formed in the shaft portion 15B of the anchor portion 15 in the radial direction. The oil passage holes 15G allow fuel in the fuel passage 3 to be directed to the valve portion 14 side. To be distributed.

  16, 16,... Are concave grooves formed on the upstream end surface of the anchor portion 15 as adhesion preventing grooves, and each concave groove 16 is an end surface (annular convex portion) of the suction portion 15 </ b> A of the anchor portion 15 shown in FIG. 6. 15D) is pressed as described later to form arcuate (fan-shaped) shallow grooves extending radially outward from the center O of the anchor portion 15 as shown in FIG. Further, the annular convex portion 15D of the suction portion 15A remains as convex portions 16A, 16A,... Extending radially between the concave grooves 16.

  And even if these end grooves 16 are in contact with the end surface of the small diameter sleeve portion 10B of the core cylinder 10 even when the end surface of the anchor portion 15 (annular convex portion 15D shown in FIG. By forming a minute gap between the end surfaces, the anchor portion 15 is prevented from sticking to the end surface of the small diameter sleeve portion 10B.

  Reference numeral 17 denotes a cylindrical spring receiver fixed to the inner peripheral side of the core cylinder 10 by means such as press fitting, and 18 denotes a valve spring provided in the magnetic cylinder 2 together with the spring receiver 17. As shown in FIG. 2, it is disposed in a compressed state between the valve body 13 and the spring receiver 17, and constantly biases the valve body 13 in the valve closing direction. The valve spring 18 holds the valve portion 14 of the valve body 13 in a state of being seated on the valve seat 11B of the valve seat member 11, and at this time, between the suction portion 15 </ b> A of the anchor portion 15 and the core cylinder 10. A gap S is formed as shown in FIG.

  Further, when the electromagnetic coil 7 is fed to form a closed magnetic path H (illustrated by a dotted line in FIG. 2) with the yoke 5, the core tube 10, the anchor portion 15 and the like, the attracting portion 15A of the anchor portion 15 is attached to the core tube 10. Since it is magnetically attracted, the valve body 13 separates the valve portion 14 from the valve seat 11 </ b> B of the valve seat member 11 against the spring force of the valve spring 18.

  The fuel injection valve according to the present embodiment has the above-described configuration. Next, a process of molding and processing the anchor portion 15 of the valve body 13 will be described with reference to FIGS.

  First, in step 1 in FIG. 4, the anchor portion 15 is formed as an anchor molded body 21 by the MIM method (metal injection molding) as shown in FIG. In this case, the anchor molded body 21 is obtained by uniformly kneading a binder made of a plastic material and a wax into a metal powder made of a magnetic material, and in a molten state in a mold (not shown) of an injection molding machine. It is molded by filling and filling.

  For this reason, in the anchor molded body 21 shown in FIG. 5, for example, two gate portions 22 and 22 remain on the large-diameter portion 21A side corresponding to the suction portion 15A. The anchor molded body 21 includes a small diameter portion 21B corresponding to the shaft portion 15B of the anchor portion 15, a stepped hole portion 21C corresponding to the spring accommodating portion 15F, and a pair of hole portions 21D ( Only one is shown).

  And this anchor molded object 21 removes a binder in a degreasing furnace (not shown) after taking out from the said metal mold | die, and after that, it heats and sinters in a sintering furnace (not shown), and metal It is formed so that the relative density of the tissue is in the range of 95 to 98%. For this reason, in the metal structure of the anchor molded body 21, for example, 2 to 5% of fine independent holes are formed.

  Next, in step 2 shown in FIG. 4, each gate part 22 of the anchor molded body 21 shown in FIG. 5 is removed using means such as cutting. In the next step 3, the outer peripheral surface of the large-diameter portion 21A is ground, and the anchor portion 15 is formed by cutting as shown in FIG.

  At this time, in the suction portion 15A of the anchor portion 15, a sliding surface portion 15C is formed on the outer peripheral surface as a small annular step portion over the entire circumference. And the adsorption | suction part 15A of the anchor part 15 is slidably inserted in the small diameter part 2C of the magnetic cylinder 2 via this sliding surface part 15C.

  Further, in the next step 4, as shown in FIGS. 6 and 7, the one side end face of the suction portion 15A is ground to form the annular convex portion 15D on the radially inner side, and the annular convex portion 15D is formed. An annular relief surface portion 15E that surrounds from the outside in the radial direction is formed as an annular flat surface portion. In step 5, a deburring process or the like is appropriately performed on a necessary portion of the anchor portion 15.

  Next, in step 6, the annular convex portion 15D of the suction portion 15A shown in FIG. 6 and FIG. 7 is pressed to form a plurality of concave grooves 16, 16,. It is formed as a fan-shaped (arc-shaped) shallow groove extending radially outward from the center O of the portion 15 in the radial direction. Further, the convex portions 16A, 16A,... Extending radially between these concave grooves 16 are left as non-processed portions that are not pressed.

  Then, in step 7, a plating process such as hard chrome plating is performed to complete the anchor portion 15. Further, in the anchor portion 15 formed in this way, a spherical valve portion 14 is fixed to the tip end side of the shaft portion 15B by means of laser welding or the like, and the valve body 13 shown in FIG. 3 is manufactured.

  Next, the operation of the fuel injection valve according to the present embodiment will be described. First, when the electromagnetic coil 7 is energized from the connector 9 side, a closed magnetic path H is formed as shown by a dotted line in FIG. 2, and this closed magnetic path H is a gap between the anchor portion 15 of the valve body 13 and the core cylinder 10. Pass S.

  As a result, the valve body 13 is magnetically attracted by the core cylinder 10 and is displaced in the axial direction against the valve spring 18, and the valve portion 14 is separated from the valve seat 11B of the valve seat member 11 and opened. I speak. Thereby, the fuel supplied into the fuel passage 3 is injected from the injection port 11A toward the intake pipe of the engine, the combustion chamber (not shown), and the like.

  On the other hand, when the energization to the electromagnetic coil 7 is stopped, the magnetic force between the anchor portion 15 of the valve body 13 and the core cylinder 10 is lost, so that the valve portion 14 of the valve body 13 is pushed by the urging force of the valve spring 18. By being moved, it is seated on the valve seat 11B of the valve seat member 11, and the injection port 11A is closed (closed).

  Thus, according to the present embodiment, the anchor portion 15 of the valve body 13 is formed into a stepped cylindrical shape using a metal injection molding means called a so-called MIM method, and the anchor portion 15 has a relative density of the metal structure of 95. By sintering so as to be in the range of ˜98%, fine independent pores are formed in the remaining 2% to 5% in the metal structure of the anchor portion 15.

  Therefore, after forming the anchor portion 15 by the MIM method, the concave grooves 16, 16,... For preventing adhesion may be formed by pressing or the like on the end surface of the suction portion 15A of the anchor portion 15 as shown in FIGS. It is possible to absorb the escape of the meat crushed by the press to the outer diameter side of the suction portion 15A by the air holes, and to improve the change of the outer diameter of the suction portion 15A (sliding surface portion 15C). Can be suppressed.

  In this case, it is preferable to set the relative density of the metal structure within the range of 97 to 98% in the anchor portion 15 formed by the MIM method in consideration of magnetic properties, strength, weldability, and the like. However, the above-described effects can be obtained even with the anchor portion 15 having a relative density of the metal structure in the range of 95 to 97%.

  Therefore, according to the present embodiment, the anchor portion 15 of the valve body 13 can be easily formed by using metal injection molding means such as the MIM method, and the outer diameter of the anchor portion 15 changes when the concave groove 16 is processed. Can be surely prevented.

  And when the valve body 13 which consists of the anchor part 15 formed in this way is assembled | attached in the small diameter part 2C of the magnetic cylinder 2 so that sliding displacement is possible, between the anchor part 15 of the valve body 13 and the small diameter part 2C The sliding resistance can be kept small, and the responsiveness when the valve body 13 is opened and closed can be reliably improved.

  In addition, after the concave groove 16 for preventing adhesion is pressed on the end face of the adsorption portion 15A of the anchor portion 15, it is not necessary to perform finishing grinding or the like again as in the prior art. Thereby, the man-hour of finishing can be reduced reliably, and the workability | operativity in manufacturing and assembling the valve body 13 of a fuel injection valve can be improved.

  In the embodiment described above, the plurality of grooves 16 extending radially on the end face (annular convex portion 15D) of the suction portion 15A of the anchor portion 15 are described as being press-molded. However, the present invention is not limited to this. For example, a plurality of parallel grooves extending in a straight line, a plurality of grooves extending in a curved shape, or a plurality of concave and convex portions are pressed on the annular convex portion 15D of the anchor portion 15. It may be formed by a processing means, thereby forming an adhesion preventing groove.

It is a longitudinal cross-sectional view which shows the fuel injection valve by embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the core cylinder, valve body, valve seat member, etc. in FIG. It is an expanded sectional view which shows the valve body in FIG. 1 alone. It is a flowchart which shows a shaping | molding of an anchor part, and a manufacturing process. It is an expanded sectional view which shows the anchor part shape | molded by the MIM method alone. It is an expanded sectional view which shows the state which gave the grinding process to the outer peripheral surface etc. of the anchor part. It is a top view of the anchor part shown in FIG. It is a top view in the same position as Drawing 7 showing the state where a plurality of concave grooves were formed in the end face of an anchor part.

Explanation of symbols

2 Magnetic cylinder 3 Fuel passage 5 Yoke 7 Electromagnetic coil 10 Core cylinder 11 Valve seat member 11A Injection port 11B Valve seat 13 Valve body 14 Valve part 15 Anchor part 16 Concave groove (adhesion prevention groove)
17 Spring bearing 18 Valve spring H Closed magnetic circuit

Claims (3)

A magnetic cylinder formed in a cylindrical shape with a magnetic material and having a fuel passage inside, a core cylinder formed in a cylindrical shape with a magnetic material and inserted into the magnetic cylinder, and downstream of the core cylinder A valve seat member having a valve seat that is provided in the magnetic cylinder and is disposed on the side, and is positioned between the core cylinder and the valve seat member so as to be slidable and displaceable in the magnetic cylinder. A fuel injection valve comprising a valve body provided and seated on and off of the valve seat of the valve seat member;
The valve body is provided at a cylindrical anchor portion extending in the axial direction in the magnetic cylinder body and having an upstream end facing the core tube, and a downstream end of the anchor portion. It consists of a valve part that is seated on and off the valve seat,
The anchor portion of the valve body is formed by injection molding metal powder made of a magnetic material and sintering it so that the relative density is in the range of 95 to 98%,
A fuel injection valve characterized in that an upstream end face of the anchor portion is provided with an adhesion prevention groove for preventing the anchor portion from coming into close contact with the core cylinder.   2. The fuel injection valve according to claim 1, wherein the adhesion prevention groove is formed by press-molding a plurality of concave grooves on an end surface of the anchor portion.   3. The fuel injection valve according to claim 1, wherein the adhesion prevention groove is configured by a plurality of radially extending concave grooves formed on an end surface of the anchor portion.

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