JP2008095531A - Solenoid-operated fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To absorb radial bending load caused by axial eccentricity between a mounting hole of an engine and a delivery pipe when mounting a cylinder fuel injection type injector to the engine. <P>SOLUTION: A fuel lead-in pipe part 16 is disposed between a fuel lead-in port 26 of the injector 1 and an upper part (upstream) of a fixed core 15. A plurality of grooves 16a is formed at an intermediate part of the fuel lead-in pipe part 16 at a lower part (downstream) of a seal ring 18 and a backup ring 17 provided near the fuel lead-in port 26 to prevent a leakage of fuel from a connecting hole B of fuel piping. The radial bending load caused by axial eccentricity between the cylinder block mounting hole A and the delivery pipe B in mounting the engine is absorbed by a flexible part formed of the plurality of grooves 16a. A structure of not transmitting the radial bending load to a valve seat 22 and a movable valve 8 of the injector 1 is provided to form the injector stable in the injected fuel injection flow and spraying shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic fuel injection valve, and more particularly to an internal structure of a fuel injection valve that absorbs shaft eccentricity when an engine is mounted.

  In an electromagnetic fuel injection valve (hereinafter referred to as an injector), a movable valve is attracted and separated from a valve seat by a magnetic force (magnetic attraction force) generated by energizing the inside, and fuel is injected. When an injector is used in an engine, it is known that the amount of injected fuel and the shape of fuel spray affect the combustion performance of the engine.

  In particular, an in-cylinder fuel injection injector for a gasoline engine has a structure in which fuel is directly supplied into a combustion chamber, and is required to inject and form an accurate required fuel amount and fuel spray in a short time. When mounting the injector to the injector mounting hole of the engine cylinder head or cylinder block, the outer periphery of a ring-shaped elastic member (seal ring) that is fixed at the contact surface of the mounting hole and seals the fuel provided in the fixed core of the injector The inner diameter of the delivery pipe is inserted into the.

  In general, the center of the injector mounting hole of the cylinder head or cylinder block of the engine and the center of the inner diameter of the delivery pipe each have a radial axial eccentricity, and when the injector is mounted, the diameter is set to the injector via the ring-shaped elastic member. Directional bending load is generated.

  As shown in FIG. 2, in the conventional injector structure, the bending load is deformed and absorbed only by the ring-shaped elastic body member 18, and the load is positively applied to the internal component member having a rigid body structure, for example, the fixed core 15. It does not have a function to absorb it.

  In this structure, when the bending load is large, the outer diameter part of the fuel injection hole of the rigid injector is in contact with the inner wall of the mounting hole with the axial contact surface of the injector and the cylinder head or cylinder block mounting hole as a fulcrum. There is a problem that a radial bending load is generated in the valve seat and the movable valve of the injector.

  As a configuration for solving this problem, Patent Document 1 discloses a configuration in which a fuel distribution conduit and a fuel injection valve are connected by a bellows (corrugated tube) having a thin metal wall.

JP 2005-51954 A

  In the above prior art, when the shaft mounting eccentricity of the engine and the delivery pipe are large, the bending force that cannot be absorbed by the ring-shaped elastic member is the fuel injection of the injector having a rigid structure with the contact surface between the injector and the mounting hole as a fulcrum. The outer diameter part of the hole comes into contact with the inner wall of the mounting hole. Therefore, a radial bending load acts on the valve seat and the movable valve of the injector, increasing the axial sliding resistance of the movable valve and delaying the opening / closing valve speed. It becomes a factor to deteriorate the shape.

  Moreover, the thing of patent document 1 connects and arranges a corrugated pipe | tube between a fuel distribution conduit and a fuel injection valve. The corrugated tube has two end sections, one having a configuration in which one is concentrically joined with a fuel injection valve feed section and the other with a fuel distribution conduit feed section. However, since the corrugated pipe is provided outside the fuel injection valve in the cited reference 1, both the fuel distribution conduit and the fuel injection valve must be provided with a seal mechanism and a connecting portion with the corrugated pipe, and the number of parts is large. There is a problem that the number of assembly steps increases.

  In view of the problems of the prior art, the object of the present invention is to absorb the radial bending load consisting of the shaft eccentricity generated when the injector is mounted on the engine, and to reduce the number of parts with a stable injection flow rate and spray shape. It is to provide with assembly man-hours.

  In order to achieve the above object, the injector of the present invention can be attached to an engine, and can be inserted into a connection hole of a delivery pipe for fuel transportation for an automobile, so that a fuel introduction port of an injection valve body can be directly inserted through a seal ring. The injection valve body includes a nozzle body having a valve seat and a movable valve body, a yoke that houses an electromagnetic coil, a hollow cylindrical fixed core positioned at the center of the injection valve body, The seal ring is fixed to the outer periphery with the fuel introduction port, and a fuel introduction pipe part that forms a center core of the injection valve body in cooperation with the fixed core, and a connector that covers at least a part of the center core In the electromagnetic fuel injection valve composed of the exterior resin, the intermediate portion of the fuel introduction pipe portion is flexible enough to absorb the shaft eccentricity between the engine mounting hole and the connection hole of the delivery pipe. Parts characterized by being formed.

  According to the present invention, the radial bending load formed by the shaft eccentricity of the engine cylinder mounting hole and the delivery pipe is absorbed, and the structure is such that the radial bending load is not transmitted to the valve seat and the movable valve of the injector. The fuel injection flow rate and spray shape can be stabilized by the number of parts and the number of assembly steps.

  FIG. 1 shows a cross-sectional structure of an embodiment of an injector according to the present invention. The injector of the present invention can be directly attached to the engine. This is an electromagnetic fuel injection valve in which a fuel introduction port 26 of an injection valve body can be directly inserted through a seal ring (O-ring) 18 into a connection hole B of a delivery pipe for transporting automobile fuel.

  The injection valve body includes a nozzle body having a valve seat 22 and a movable valve body 7, a yoke 4 that houses the electromagnetic coil 3, a hollow cylindrical fixed core 15 that is positioned at the center of the injection valve body, and a fuel inlet 26. The seal ring 18 is fixed to the outer periphery. Furthermore, it is comprised by the fuel introduction pipe | tube part 16 which cooperates with the fixed core 15 and forms the center core of an injection valve main body, and exterior resin with a connector which covers at least one part of the said center core. A flexible part capable of absorbing the shaft eccentricity between the engine mounting hole A and the delivery hole B of the delivery pipe is formed in the middle part of the fuel introduction pipe part 16. Hereinafter, it demonstrates in detail using FIG. 1, FIG. 3-FIG.

  The injector 1 is supplied with pressurized fuel from a fuel pump (not shown) through a connection hole B of a delivery pipe. The injector 1 opens and closes a fuel passage between the movable valve 7 and a valve seat surface (seat surface) 22 formed inside the orifice plate 8 to control the fuel injection amount from the fuel injection hole 8a. . In the vicinity of the valve seat surface 22, there is provided a fuel swirling member 9 for imparting a swirling force to the fuel for atomizing the fuel. Thereby, the injected fuel spray is formed as a conical atomized spray.

  As a means for generating the driving force of the movable valve 7, the injector 1 is provided with a coil 3. When the coil 3 is not energized and there is no magnetic attractive force, a return spring 14 as a spring member is provided so that the movable valve 7 is pressed against the valve seat surface 22 to close. When the coil 3 is energized, a magnetic flux is generated, and a magnetic attraction force is generated between the fixed core 15, the housing 24 and the movable valve 7 using the fixed core 15, the yoke 4, the housing 24 and the movable valve 7 as a magnetic circuit. . As a result, the movable valve 7 is displaced away from the valve seat surface 22 (upper side in FIG. 1), and fuel is injected from the fuel injection hole 8a. For the magnetic circuit, for example, ferritic stainless steel, which is a magnetic material, is used.

  The engine mounting hole A is a mounting hole for a cylinder head or a cylinder block of an engine in which the injector is mounted. When the axial eccentricity is large in the center of the mounting hole A and the inner diameter center of the delivery pipe B, if the axial eccentricity is large, the seal ring 18 and the injector 1 are large in the radial direction when the injector 1 is mounted. Bending load is generated. Depending on the size of the seal ring, if an example is given, the absorption of eccentricity by the seal ring (O-ring) is about 0.3 mm.

  The bending load that cannot be absorbed by the seal ring 18 is such that the nozzle tip outer diameter portion 6a of the injector 1 having a rigid structure contacts the inner wall A2 of the mounting hole A with the contact surface A1 of the injector 1 and the engine mounting hole A as a fulcrum. . For this reason, a radial bending load is generated on the valve seat surface 22 and the movable valve 7 of the injector 1, the axial sliding resistance of the movable valve 7 is increased, the opening / closing valve speed is delayed, and the fuel is injected from the fuel injection hole 8 a. This is a factor that deteriorates the fuel injection flow rate and the spray shape.

  The injector 1 of the present invention forms a flexible portion at the intermediate portion of the internal component member (fuel introduction pipe portion 16) upstream (upper side in the drawing) from the fulcrum of the contact surface A1 of the mounting hole A when the engine is mounted. The flexible portion absorbs a large bending load in the radial direction due to the axial eccentricity of the mounting hole A and the delivery pipe B, which cannot be absorbed by the ring 18 alone.

  In FIG. 1, a fuel introduction pipe portion 16 made of a metal material is provided from the fuel introduction port 26 to the upper portion of the fixed core 15, and the joining of the fixed core 15 and the fuel introduction pipe portion 16 is performed by welding, for example. The fuel introduction pipe 16 is provided with a plurality of grooves 16 a that facilitate bending deformation at the lower part of the backup ring 17 that backs up the seal ring 18. By providing the fuel introduction pipe 16 having a plurality of grooves 16 a, it is possible to absorb the bending load in the radial direction and not transmit the bending load to the valve seat surface 22 and the movable valve 7.

  The fuel introduction pipe portion 16 may be magnetic stainless steel or non-magnetic austenitic stainless steel. In the former case, the center core composed of the fixed core 15 and the fuel introduction pipe portion 16 can be integrally formed. In the latter case, the fuel introduction pipe portion 16 is formed. Can be cheap. Further, the fuel introduction pipe portion 16 may be made of a material having spring characteristics. As an example, the thickness of the fuel introduction pipe portion 16 and the groove 16a is 2 mm for the pipe portion and 0.5 to 0.8 mm for the groove portion.

  On the outside of the fuel introduction pipe portion 16, an exterior resin portion 19 is integrally formed with a connector exterior and a receiving seat (flange) 27 of the backup ring 17. In the exterior resin part 19, the exterior resin thin part 19a having a constriction is formed in a portion where the plurality of grooves 16a are exteriorized so as to cope with the bending of the groove (FIG. 3).

  The injector 1 configured as described above sets the delivery hole B of the delivery pipe in the upper part of the injector 1 after mounting the injector 1 in the engine mounting hole A of the cylinder head or cylinder block. Alternatively, after setting the connection hole B of the delivery pipe in the upper part of the injector 1, the lower part of the injector 1 is mounted in the engine mounting hole A. The injector 1 including the fuel introduction pipe portion 16 is an integrated type, so that it is robust and easy to mount with the engine attachment hole A and the delivery pipe connection hole B.

  The plurality of groove shapes 16a provided in the fuel introduction pipe portion 16 can be variously modified in addition to the rectangular shape shown in FIGS. For example, the injector shown in FIG. 4 has a V-shaped groove 16a. Further, the injector shown in FIG. 5 has an R-shaped groove 16a.

  FIG. 6 shows a partial configuration of an injector according to another embodiment of the present invention. An intermediate part of the fuel introduction pipe part 16 is formed in a waveform from the lower part of the backup ring 17 and is joined to the upper part (upstream side) of the fixed core 15. In this example, the exterior resin portion 19 is provided below the side surface of the adjuster 20, and the exterior resin thin portion 19a disposed in the middle portion of the fuel introduction pipe portion 16 is not provided as shown in FIG. In this case, the receiving seat portion 25 of the backup ring 17 can be formed by resin molding as a separate body or by joining a metal half ring to the fuel introduction pipe portion 16.

  In this way, the fuel insertion pipe portion having the flexible portion above the fulcrum of the contact surface A1 of the engine attachment hole A absorbs the radial bending load generated when the injector is attached, and the valve seat and the movable valve are in the radial direction. Since the bending load is not transmitted, it is possible to stabilize the injected fuel flow rate and the spray shape.

  Although the present invention has been described with reference to a fuel injection valve used in a cylinder injection type internal combustion engine, it can also be applied to a fuel injection valve of a port injection type internal combustion engine.

1 is a longitudinal sectional view of an injector according to an embodiment of the present invention. The fragmentary longitudinal cross-section of the injector which shows a prior art. The fragmentary longitudinal cross-section of the injector which shows the thin part of an exterior resin part. The fragmentary longitudinal cross-sectional view of the injector which shows the other example of a fuel introduction pipe groove shape. The fragmentary longitudinal cross-section of the injector which shows the further another example of a fuel introduction pipe groove shape. The fragmentary longitudinal cross-section of the injector by the other Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Injector, 2 ... Bobbin, 3 ... Electromagnetic coil, 4 ... Yoke, 5 ... Housing, 6 ... Nozzle, 6a ... Nozzle tip outer diameter part, 7 ... Movable valve, 8 ... Orifice plate, 8a ... Fuel injection hole, 9 DESCRIPTION OF SYMBOLS ... Fuel turning member, 10 ... Combustion gas seal member, 11 ... Movable valve guide, 12 ... Spacer, 13 ... Seal member, 14 ... Return spring, 15 ... Fixed core, 16 ... Fuel introduction pipe part, 16a ... Fuel introduction pipe part Outer diameter groove, 17 ... Backup ring, 18 ... Seal ring (ring-shaped elastic member), 19 ... Exterior resin part, 19a ... Exterior resin thin part, 20 ... Adjuster, 21 ... Filter, 22 ... Valve seat surface, 24 ... Housing, 25 ... receiving seat (flange), 26 ... fuel inlet, A ... engine mounting hole, A1 ... contact surface of mounting hole, A2 ... mounting hole inner wall, B ... delivery pipe (fuel) Connection hole of the material piping).

Claims (6)

An electromagnetic fuel injection valve that can be attached to an engine and in which a fuel introduction port of an injection valve body can be directly inserted into a connection hole of a delivery pipe for fuel transportation for an automobile via a seal ring,
The injection valve body includes a nozzle body having a valve seat and a movable valve body, a yoke that houses an electromagnetic coil, a hollow cylindrical fixed core positioned at the center of the injection valve body, and an outer periphery that has the fuel introduction port. The seal ring is fixed to a fuel introduction pipe part that forms a center core of the injection valve body in cooperation with the fixed core, and an exterior resin with a connector that covers at least a part of the center core. In the electromagnetic fuel injection valve
An electromagnetic fuel injection valve characterized in that a flexible part capable of absorbing an axial eccentricity between an engine mounting hole and a connection hole of a delivery pipe is formed in an intermediate part of the fuel introduction pipe part.   The electromagnetic fuel injection valve according to claim 1, wherein the flexible portion has a plurality of grooves formed on an outer peripheral surface of an intermediate portion of the fuel introduction pipe portion.   2. The electromagnetic fuel injection valve according to claim 1, wherein the flexible portion forms an intermediate portion of the fuel introduction pipe portion in a wavy shape.   Part of the exterior resin covers the outer periphery including the flexible part of the fuel introduction pipe part, and the part of the resin part covering the fuel introduction pipe part that covers the flexible part is thinner than the other part. The electromagnetic fuel injection valve according to claim 1, wherein a flange for holding the seal ring is formed in the resin portion.   The electromagnetic fuel injection valve according to any one of claims 1 to 4, wherein the fixed core and the fuel introduction pipe portion constituting the center core are made of different materials, the former being a magnetic member and the latter being a nonmagnetic member.   The electromagnetic fuel injection valve according to any one of claims 1 to 4, wherein the fixed core and the fuel introduction pipe portion constituting the center core are integrally formed of the same magnetic material.

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