JP2006002780A - Solenoid-operated fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid-operated fuel injection valve capable of exerting an excellent performance by securing a sufficient magnetic circuit while the construction is established with a small size and thin diameter and the cost is suppressed. <P>SOLUTION: Three members are coupled together by welding, i.e. a fuel introducing pipe 40 formed through press working, a stationary core 1 in a hollow cylindrical shape having a flange at the top, and a nozzle holder 18 formed into a thin and long cylinder through press working and having at the bottom an orifice plate furnished with a valve seat. The upper inside surface of the nozzle holder 18 and the peripheral surface of the stationary core 1 are welded upon fitting by pressure to each other, so as to yield an assembly welded, where a movable core 14 and a valve element 16 are coupled together through a joint 15 having a spring function. A solenoid coil 2 is arranged at the periphery of the noise holder 18, and on its outside a cylindrical yoke 4 is installed, wherein the top of the yoke 4 is welded fast to the flange 1a of the stationary core 1 and the bottom is fitted by pressure on the nozzle holder 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic fuel injection valve for an internal combustion engine.

  Conventionally, in an internal combustion engine such as an automobile, an electromagnetic fuel injection valve that is driven by an electric signal from an engine control unit has been widely used.

  This type of conventional electromagnetic fuel injection valve includes, for example, an electromagnetic coil and a yoke around a hollow cylindrical fixed core (center core) disclosed in JP-A-10-339240 and JP-A-11-132127. A nozzle body with a mover having a valve body is attached to the lower part of the yoke that houses the electromagnetic coil, and the mover is biased toward the valve seat by the force of a return spring. I am doing.

JP 10-339240 A JP-A-11-132127

  In the above-described conventional example, secondary injection due to rebound when the valve is closed is not considered.

    The objective of this invention is providing the fuel injection valve which can respond to subjects, such as prevention of the secondary injection of a fuel, by suppressing the rebound of the valve body at the time of valve closing.

  In order to achieve the above object, according to the present invention, in an electromagnetic fuel injection valve, in a fuel passage assembly, a mover formed by coupling a movable core and a valve body, and this mover is attached to the valve seat side. And a member for adjusting the spring force of the return spring is incorporated, and an electromagnetic coil is arranged on the outer periphery of the nozzle holder at a position where it is press-fitted and fitted, and a cylindrical shape is formed on the outer side thereof. The yoke is characterized in that the upper end of the yoke is welded to the flange of the fixed core and the lower end is press-fitted to the outer periphery of the nozzle holder.

A movable element having a valve body; a return spring that applies a spring load to the movable element on the valve seat side; an electromagnetic coil; and a magnetic circuit that magnetically attracts the movable element toward the valve opening side by excitation of the electromagnetic coil; In an electromagnetic fuel injection valve equipped with
The movable element has a movable core as an element of the magnetic circuit, the movable core and the valve body are connected via a joint having a spring function, and a leaf spring is incorporated in the movable element, A mass body that is movable in the axial direction independently of the mover is disposed between the return spring and the leaf spring.

  As described above, according to the present invention, it is possible to provide a fuel injection valve that suppresses the rebound of the valve body when the valve is closed and reduces the secondary injection of fuel.

  Embodiments of the present invention will be described with reference to examples shown in the drawings.

  FIG. 1 is a longitudinal sectional view of a fuel injection valve according to one embodiment of the present invention, FIGS. 2 and 3 are longitudinal sectional views showing a part thereof exploded, and FIG. 4 is a valve body and an orifice plate used in the above embodiment. FIG. 5 to FIG. 9 show components used in this embodiment, and FIG. 10 is an exploded perspective view of the whole.

  First, an overall outline of the present embodiment will be described.

  As shown by the arrow in FIG. 1, the fuel injection valve 100 is a so-called top feed in which fuel flows in from the upper part of the injection valve main body and flows in the axial direction when the valve is opened, and is injected from an orifice 20 provided at the lower end of the injection valve. The system is illustrated.

  As a main element constituting the fuel passage in the axial direction of the injection valve main body 100, press working (for example, deep drawing, extruding, etc., in which other parts described below are pressed) is also performed. Nozzle holder (referred to as a nozzle body) having a fuel-introducing fuel pipe 40, a hollow cylindrical fixed core 1 having a flange 1a at the upper end, and an orifice plate 19 with a valve seat on the lower end side, which is pressed into a long and narrow cylindrical shape by a pipe. 18).

  As shown in FIGS. 1 and 2, the fuel introduction pipe 40 is provided with flanges 40a and 40b at the upper and lower ends, and the flange 40b on the lower end side is welded to the upper surface of the flange 1a of the fixed core 1 at a position indicated by reference numeral W6. ing. This welding is performed in the circumferential direction of the flange, whereby the fixed core 1 and the fuel introduction pipe 40 are connected in advance before the assembly of the injection valve body.

  The upper inner periphery of the nozzle holder 18 and the outer periphery of the fixed core 1 are press-fitted and further welded over the entire periphery at a position indicated by reference numeral W1, whereby the nozzle holder 18 and the fixed core 1 are coupled. In this way, the pipe 40, the fixed core 1, and the nozzle holder 18 are connected in series to form one fuel passage assembly.

  In this fuel passage assembly, a movable element 5 formed by connecting a cylindrical movable core 14 and an elongated valve element (including a valve rod) 16 via a joint pipe 15 described later, and the movable element 5 are provided. A return spring 7 that is biased toward the valve seat 19a, a member that adjusts the spring force of the return spring 7 (in this example, a C-ring pipe whose cross section has a C-ring shape) 6 and the like are incorporated.

  In the nozzle holder 18, the electromagnetic coil 2 is arranged on the outer periphery of the position where the fixed core 1 is press-fitted and fitted, and the cylindrical yoke 4 is arranged on the outer side thereof.

  The yoke 4 is a pressed cylinder (the details of the shape will be described later), and its upper end is opened so that the electromagnetic coil 2 can be accommodated, and this upper end edge is indicated by a symbol W5 on the flange 1a of the fixed core 1. It is welded over the entire circumference in position. The lower end portion 4c of the yoke 4 is narrowed more narrowly than the portion 4a for accommodating the electromagnetic coil, and the lower end portion 4c is press-fitted to the outer periphery of the nozzle holder 18.

  In the fuel injection valve 100, when the electromagnetic coil 2 is energized, the yoke 4, the fixed core 1, the movable core 14, and a part of the nozzle holder 18 form a magnetic circuit. A valve opening operation is performed by suctioning against the force. When the energization of the electromagnetic coil 2 is stopped, the movable element 5 comes into contact with the valve seat 19a by the force of the return spring 7, and the valve is closed. In this example, the lower end surface of the fixed core 1 serves as a stopper for receiving the mover 5 during the valve opening operation.

  Here, the characteristics of each component described above will be described.

  The fixed core 1 is made of magnetic stainless steel and is formed into an elongated hollow cylindrical shape having a flange 1a at the upper end by pressing and cutting.

  The flange 1a is provided with a window 1b through which the terminal 29 and the pin terminal 30 of the electromagnetic coil 2 are passed.

  The fuel introduction pipe 40 is formed of a non-magnetic metal member, and a lower portion thereof is narrowed by pressing, and a C-ring pin 6 having a C-shaped cross section is press-fitted into the inner periphery of the lower portion. The load of the return spring 7 is adjusted by adjusting the press-fit amount of the pin 6. A fuel filter 31 is attached to the upper end of the fuel introduction pipe 40.

  The nozzle holder 18 is made of a magnetic material, but the periphery of the fixed core 1 where the lower end surface is located (the position where the annular groove 18d is located in this example) is subjected to non-magnetic or weak magnetic treatment by high-frequency quenching. (Hereinafter referred to as non-magnetic treatment including weak magnetic treatment).

  The position where the non-magnetic treatment is performed is the vicinity where the lower end surface (magnetic attraction surface) of the fixed core 1 is located, in other words, in the nozzle holder 4, a perpendicular line perpendicular to the axis of the fixed core 1 at the fixed core lower end position. This is a region having a width (a width slightly wider than the annular groove width H in FIG. 1) in the vertical direction centering on the position through which the An annular groove 18d having a trapezoidal cross section is provided on the outer peripheral surface of the nozzle holder in this region.

  The reason why the annular groove 18d is provided in this way is to prevent leakage magnetic flux from being generated in the magnetic circuit for magnetically attracting the mover 5 together with the nonmagnetic treatment. In other words, a part of the nozzle holder 18 of this example, [the periphery of the lower end surface (magnetic attraction surface) of the fixed core 1], is subjected to nonmagnetic treatment to cause magnetic flux leakage in the magnetic circuit near the lower end surface of the fixed core 1. This prevents magnetic flux from flowing from the fixed core 1 to the movable core 14 in a concentrated manner. However, even if a non-magnetic treatment is performed, it is difficult to completely demagnetize, and a part of the magnetic flux also flows to the non-magnetic treatment part to some extent. The holder 18 is thinned to increase the magnetic resistance.

  In the nozzle holder 18, the diameter of the portion into which the fixed core 1 is press-fitted and the upper portion 18a of the holder that accommodates the movable core 14 is the largest among the nozzle holders, and the intermediate portion 18b where the joint between the movable core 14 and the valve body 16 is located. Is formed in a tapered shape, and the lower part 18c of the holder in which the valve body located below is further narrowed to form a so-called long nozzle type nozzle holder 18.

  In addition to the above-described annular groove 18d, an annular groove 18e is provided on the outer periphery of the holder upper portion 18a with a space therebetween. Reference sign W1 in the annular groove 18e is a welded portion between the nozzle holder 18 and the fixed core 1, and the nozzle holder 18 is welded over the entire circumference of the fixed core 1 at this position W1. This weld W1 seals between the inner periphery of the nozzle holder 18 and the fixed core 1, and prevents leakage of fuel passing through the injection valve main body 100.

  In addition, by setting the welding position W1 to the annular groove 18e, welding can be performed on the thin wall portion of the nozzle holder 18, thereby saving the heat energy required for welding and thereby injecting with the heat of welding. It is possible to prevent thermal deformation of the valve body parts.

  A groove 18g for attaching a seal member is provided on the outer periphery of the holder lower portion (so-called long nozzle portion) 18c, and a seal member 42 such as a Teflon seal (“Teflon” is a registered trademark) is attached to the groove 18g.

  As shown in FIG. 11, the long nozzle portion 18c is provided with an intake valve 101, an intake / exhaust valve drive mechanism 102, an intake pipe 103, and the like in an injection system in which the fuel injection valve 100 is directly provided on the cylinder head 106 of the engine 105. When the density is high, the large-diameter injection valve body can be placed at a position away from these components and the cylinder head 106 (a position that does not interfere), and there is an advantage of increasing the degree of freedom of attachment. Conventionally, when the fuel injection valve 100 is attached to the cylinder head, a gasket is disposed between the bottom of the large-diameter yoke and the cylinder head to prevent the combustion gas leakage of the engine. The seal ring 42 provided on the outer periphery of the nozzle portion seals the outer periphery of the long nozzle portion 18c and the inner periphery of its insertion hole (on the cylinder head side) to prevent engine combustion gas leakage. Since it can be made small, it is possible to simplify the size and cost of the seal member.

  An orifice plate 19 and a fuel swirler (hereinafter referred to as a swirler) 21 are provided at the lower end (tip) of the nozzle holder 18, and these members 18, 19, and 21 are formed by separate members.

  The orifice plate 19 is formed of, for example, a stainless steel disk-like chip, and an injection hole (orifice) 20 is provided in the center thereof, and a valve seat 19a is formed in the upstream portion following the injection hole.

  The orifice plate 19 is designed to be attached to the inner periphery 18f of the lower end of the nozzle holder 18 by press fitting.

  On the other hand, the swirler 21 has a specification to be fitted to the inner periphery of the lower end of the nozzle holder 18 and is formed of a sintered alloy.

  FIG. 9 shows the detailed shape of the swirler 21, wherein (a) is a top view, (b) is a CC cross-sectional view, and (c) is a bottom view.

  The swirler 21 is a chip having a shape close to an equilateral triangle and provided with R on three sides instead of the apex, and a central hole (guide) 25 for slidingly guiding the tip (valve element) of the mover 5 at the center thereof. In the upper surface, guide grooves 24 for guiding fuel to the outer peripheral three sides 21 'are formed radially outwardly with the annular groove 24' as the center.

  On the other hand, an annular step (flow path) 23 is formed on the outer periphery of the lower surface of the swirler 21, and a plurality of passage grooves 26 for fuel swirl formation are provided between the annular flow path 23 and the central hole 25, for example, Six are arranged.

  The passage groove 26 is formed so as to be substantially tangential from the outer diameter side of the swirler 21 to the inner diameter, and is set so that a swirling force is generated in the fuel ejected from the passage groove 26 toward the lower end of the central hole 25. .

  The reason why the annular step 23 is provided is that it is necessary as a fuel reservoir. Further, a chamfer 21 ′ having three sides is formed on the outer periphery of the swirler 21. The chamfer 21 ′ secures a fuel passage between the swirler 21 and the inner periphery of the nozzle holder 18 when the swirler 21 is fitted to the tip of the nozzle holder 18, and serves as a reference when the grooves 24 and 26 are processed. Make. The R surface provided on the outer periphery of the swirler 21 fits into the inner periphery of the tip of the nozzle holder 18.

  When the shape of the swirler 21 is a shape close to a substantially equilateral triangle with an R as described above, there is an advantage that a fuel flow rate can be sufficiently secured as compared with a chip having more polygonal sides.

  An inner periphery (stepped inner periphery) 18 f with a receiving surface 18 e for mounting the swirler 21 and the orifice plate 19 is provided at the tip (one end of the fuel injection side) of the nozzle holder 18. The swirler 21 is fitted into the inner periphery of the nozzle holder so as to be received by the receiving surface 18e of the nozzle holder 18, while the orifice plate 19 is press-fitted and welded to the inner periphery so as to press the swirler 21. Reference numeral W4 is welded over the entire circumference of the orifice plate 19 at the welding position.

  By mounting the swirler 21 and the orifice plate 19 in this way, the swirler 21 is held between the receiving surface 18 e and the orifice plate 19.

  The upper surface of the swirler 21 is provided with a fuel guide groove 24 so as to be in pressure contact with the receiving surface 18 e provided on the nozzle holder 18, so that the fuel on the swirler upstream side passes through the groove 24 and the fuel flow path 22 on the outer periphery of the swirler 21. It is supposed to flow through.

  As shown in FIG. 3, the movable core 14 and the valve body 16 in the mover 5 are connected through a joint 15 having a spring function. A leaf spring (damper plate) 50 is incorporated in the mover 5 between the movable core 14 and the joint 15.

  Further, as shown in FIG. 1, a mass body (weight, movable) that is movable in the axial direction independently of the mover 5 from the shaft hole f constituting the fuel passage of the fixed core 1 to the shaft hole provided in the movable core 14. 41 (sometimes referred to as a mass or the like) 41 is arranged. The mass body 41 is located between the return spring 7 and the leaf spring 50. Therefore, the spring load of the return spring 7 is applied to the mover 5 via the mass body 41 and the leaf spring 50.

  2 and 3, the movable core 14 has an upper shaft hole 14a for introducing a part of the mass body 41 and a lower shaft hole 14b having a diameter larger than that of the upper shaft hole 14a.

  The joint 15 is composed of a cup-shaped pipe in which an upper cylindrical portion 15a and a lower cylindrical portion 15c having a diameter smaller than that are integrally formed. The upper cylindrical portion 15a is fitted into the lower shaft hole 14b of the movable core 14 and welded over the entire circumference with the movable core 14 at the position indicated by reference numeral W2, whereby the joint 15 and the movable core 14 are coupled.

  A leaf spring 50 is interposed between the inner diameter step surface 14 c between the upper shaft hole 14 a and the lower shaft hole 14 b of the movable core 14 and the upper end surface of the upper cylindrical portion 15 a of the joint 15. The upper part of the valve body (valve rod) 5 of the mover is welded to the lower cylindrical portion 15c of the joint 15 at the position indicated by the symbol W3 over the entire circumference.

  A step 15b between the upper cylindrical portion 15a and the lower cylindrical portion 15c of the joint 15 has a function as a leaf spring.

  As shown in FIG. 6, the leaf spring 50 has an annular shape, and a portion indicated by reference numeral 51 on the inside thereof is a punched portion, and by this punching, a plurality of elastic pieces 50a are formed to protrude inward, and these elastic pieces 50a. Are arranged at equal intervals in the circumferential direction.

  The lower end of the cylindrical movable mass body 41 is received by the elastic piece 50a of the leaf spring 50.

  In the present embodiment, the leaf spring 50 receives the mass body (first mass body) 41, and the leaf spring portion (step portion) 15b of the joint 15 receives the movable core (second mass body) 14. Therefore, the mass body And the leaf spring function (damper function) which receives it becomes a double structure.

  When the movable element 5 collides with the valve seat 19a due to the spring force of the return spring 7 during the closing operation of the fuel injection valve, the impact is first absorbed by the leaf spring portion 15b of the joint 15, and the movable element 5 rebounds. The kinetic energy is absorbed by the inertia of the movable mass body 9 and the elastic deformation of the leaf spring 50 to prevent rebound. In particular, according to the double damper structure of the present embodiment, even when the return spring 7 is a cylinder injection type fuel injection valve having a large spring load, the impact energy when the valve body is closed is sufficiently attenuated, Secondary injection accompanying rebound can be effectively prevented.

  FIG. 5 shows an enlarged structure of the joint 15. The joint 15 together with the mass body 41 serves as a fuel passage f, and a plurality of holes 15d through which fuel flows to the nozzle holder 18 are provided in the step portion 15d.

  A part of the movable core 14 and the valve rod 16 serves as a movable guide surface. The inner periphery of the upper cylindrical portion 18a of the nozzle holder 18 serves as a guide surface for slidingly guiding the movable core 14, and the inner periphery of the shaft hole 25 of the swirler 21 serves as a guide surface for slidingly guiding the valve rod 16. This constitutes a so-called two-point support guide system.

  The yoke 4 is formed by press-working magnetic stainless steel, and includes a cylindrical coil housing portion 4a for housing the electromagnetic coil 2, a tapered throttle portion 4b continuing below, and a cylindrical yoke lower portion continuing below the cylindrical coil housing portion 4a. 4c.

  The upper end of the yoke is opened, and the electromagnetic coil 2 is accommodated through the opening, and is positioned by being received at a bend 4d at the inner boundary between the coil accommodating portion 4a and the tapered portion 4b. The inner periphery of the yoke lower portion 4c and the outer periphery of the nozzle holder 18 are press-fitted, and an annular gap 34 surrounded by the bobbin bottom surface of the electromagnetic coil 2, the inner periphery of the tapered portion 4b, and the outer periphery of the nozzle holder 18 is fixed. An air gap for preventing magnetic flux leakage of a magnetic circuit for attracting the mover formed by the core 1, the movable core 14, the nozzle holder 18, and the yoke 4 is formed.

  In this embodiment, the stroke of the mover 5 is defined by the valve seat 19a and the lower end of the fixed core 1.

  Therefore, the lower end surface of the fixed core 1 and the upper surface of the movable core 14 collide when the valve is closed. Therefore, as shown in FIG. 61 is given.

As shown in FIG. 7, the lower end portion 1b of the fixed core 1 is provided with a radius 1c serving as a guide curved surface for press-fitting into the nozzle holder 18 (the radius 1c is within a range indicated by reference numeral L1 in FIG. 7 in this example). R 1c is about R = 12.5 mm). In this way, the lower end 1b of the fixed core 1 is tapered by the guide curved surface 1c, so that smooth press-fitting can be ensured as compared with the case where the fixed core lower end is formed in a tapered shape. That is, in the case of a tapered taper, the intersection between the taper line and the straight line that intersects with it becomes a wide-angle edge. However, this problem does not occur in this example. The hard coating treatment 60 applied to the lower end surface of the fixed core 1 extends to the lower end side surface of the fixed core 1, but the outer diameter of the lower end of the fixed core with the thickness of the hard coating treatment added does not hinder the press-fitting. Hard coating is formed from the lower end surface of the fixed core 1 to the guide curved surface 1c (which does not exceed the range of L1), and wear resistance and impact resistance are reduced. It is illustrated.

  As shown in FIG. 4, the valve body 16 of the mover 5 has a tip formed by combining a spherical surface 16a and a conical protrusion 16b. The spherical surface 16a and the conical protrusion 16b are discontinuous as shown by 16c. Has a part. The spherical surface 16a is seated on the valve seat 19a when the valve is closed. By making the surface in contact with the valve seat 19a into the spherical surface 16a, it is possible to prevent a gap from being generated between the valve seat and the valve body even if the valve body is inclined. The conical protrusion 16b has a function of reducing the dead volume of the orifice 20 and performing a fuel rectifying action.

  Further, when the discontinuous portion 16c described above is formed, there is an advantage that the polishing finish can be easily and precisely finished as compared with the case where the conical portion and the spherical portion are continuous.

  Reference numeral 27 denotes a resin mold having a connector.

  As shown in FIG. 2, the fuel introduction pipe 40 and the fixed core 1 are welded in advance. In this state, chromium plating 60 is applied to the end face of the fixed core 1.

  Further, the orifice plate 19 is press-fitted and welded to the tip of the nozzle holder 18 with the swirler 21 interposed therebetween, and the mover 5 assembled in advance is inserted into this (the mover 5 is subjected to chrome plating 61 after being assembled). The fixed core 1 is press-fitted into the nozzle holder 18. The stroke amount of the mover 5 is determined by the press-fitting allowance of the fixed core 1. The press-fitting amount of the fixed core 1 is detected by a sensor, and the press-fitting process is finished when the predetermined press-fitting amount is reached. Next, the nozzle holder 18 and the fixed core 1 are welded.

  Next, the electromagnetic coil 2 is inserted into the outer periphery of the fixed core 1 through the bobbin, and the yoke 4 is press-fitted into the upper cylindrical portion 18a of the nozzle holder 18 from the axial direction (the press-fitted portion is the lower end portion 4c of the yoke 4). Is welded to the flange 1 a of the fixed core 1.

  Thereafter, the pin terminal 30 of the electromagnetic coil is bent and the resin mold 27 is applied. In the last step, the mass body 41, the return spring 7, the spring adjustment member 6, the fuel filter 31, the O-ring 32, and the backup ring 33 are incorporated.

According to the present embodiment, the following effects can be obtained.
(1) The fuel passage assembly in the present embodiment is configured by integrally joining the fuel introduction pipe 40, the fixed core 1, and the nozzle holder 18 by welding. In this way, only the fixed core 1 to be the main magnetic circuit is made relatively thick to secure the magnetic path, and the fuel introduction pipe 40 is not a magnetic path. In addition, the nozzle holder 18 can also be thinned, and each element of the fuel passage assembly can be set to a reasonable specification according to the respective needs. Then, mass production can be performed at low cost by pressing each element of the fuel passage assembly described above.
(2) Further, even if the nozzle holder 18 is press-fitted into the fixed core 1, the yoke 4 and the fixed core 1 are joined by the weld W5, so that the magnetic gap for driving the electromagnetic valve can be reduced as much as possible. it can. Further, the magnetic path portion of the fixed core 1 is added with the portion of the nozzle holder 18 that is press-fitted and welded thereto. At the position of the annular groove 18d, the presence of the groove 18d, the nonmagnetic treatment, and the annular gap 34 cooperate with each other. The magnetic flux leakage of the circuit is minimized, and the magnetic flux flows intensively between the lower end of the fixed core 1 and the movable core 14, thereby improving the magnetic attraction characteristics of the electromagnetic valve.
(3) Since the double damper structure effectively prevents the impact and rebound of the valve body when the fuel injection valve is closed, the secondary injection can be prevented more effectively than before.

  In the above-described embodiment, the present invention is illustrated by using the fuel injection valve of the in-cylinder injection method. However, the present invention can also be applied to the fuel injection valve disposed in the intake passage.

  In the conventional electromagnetic fuel injection valves disclosed in JP-A-10-339240 and JP-A-11-132127, for example, a composite magnetic material is used in order to reduce the number of parts and improve the assemblability. One formed pipe is magnetized, and only the middle part is made non-magnetic by induction heating or the like, so that a magnetic fuel connector part, a non-magnetic intermediate pipe part and a magnetic valve body part are integrally formed. Proposed.

  In this type, a cylindrical fixed iron core is press-fitted into the fuel connector portion, and a movable core with a valve body is provided in the valve body portion. Moreover, the electromagnetic coil is arrange | positioned at the intermediate | middle outer peripheral part of the pipe, and the yoke is arrange | positioned on the outer side of the electromagnetic coil. When the electromagnetic coil is energized, a magnetic circuit is formed in the yoke, the fuel connector portion, the fixed core, the movable core, the valve body portion, and the yoke, and the movable core is magnetically attracted to the fixed core side. The nonmagnetic part plays a role of preventing a short circuit of magnetic flux between the fuel connector part and the valve body part.

  In recent years, fuel injection valves that directly inject fuel into a cylinder of an internal combustion engine have been put to practical use in gasoline engines.

  In a direct injection type fuel injection valve, a so-called long nozzle type injector in which a nozzle body provided at a lower portion of a yoke is slender and long has been proposed. When this long nozzle injector is attached to the cylinder head, if the intake valve, intake pipe, etc. are densely packed near the cylinder head, only the thin nozzle body that does not take up space is positioned on the cylinder head. Since a large-diameter body portion such as a yoke or a connector mold can be set apart so as not to interfere with other parts or the cylinder head, there is an advantage that the degree of freedom of attachment is high.

  The purpose of this embodiment is to ensure a sufficient magnetic circuit at a low cost while reducing the size and diameter so that the main body of the fuel injection valve is suitable for the direct in-cylinder injection method described above, and has excellent performance. The object is to provide an electromagnetic fuel injection valve.

The embodiments are listed below.
Embodiment 1:
In an electromagnetic fuel injection valve, a fuel introduction pipe that has been press-processed as the main elements constituting the axial fuel passage of the injection valve body, a hollow cylindrical fixed core having a flange at the upper end, and a tubular material that is pressed into an elongated cylinder A nozzle holder having an orifice plate with a valve seat on the lower end side, the fuel introduction pipe is joined to the upper surface of the flange of the fixed core by welding, and the upper inner periphery of the nozzle holder and the outer periphery of the fixed core are press-fitted Combined by fitting and welding to form one fuel passage assembly,
Inside the fuel passage assembly, there is a mover formed by coupling a movable core and a valve body, a return spring that urges the mover toward the valve seat, and a member that adjusts the spring force of the return spring. Is built in,
An electromagnetic coil is disposed on the outer periphery of the nozzle holder at a position where it is press-fitted to the fixed core, a cylindrical yoke is disposed on the outer side thereof, the upper end of the yoke is welded to the flange of the fixed core, and the lower end is An electromagnetic fuel injection valve characterized by being press-fitted into the outer periphery of a nozzle holder.
Embodiment 2:
In an electromagnetic fuel injection valve, a hollow cylindrical fixed core having a flange, an orifice plate with a valve seat on the lower end side, and a nozzle holder for housing a mover in which a valve body and a movable core are coupled to each other,
The upper inner periphery of the nozzle holder and the outer periphery of the fixed core are joined by press fitting and welding,
An electromagnetic coil is disposed on the outer periphery of the nozzle holder at a position where it is press-fitted to the fixed core, a cylindrical yoke is disposed on the outer side thereof, the upper end of the yoke is welded to the flange of the fixed core, and the lower end is An electromagnetic fuel injection valve characterized by being press-fitted into the outer periphery of a nozzle holder.
Embodiment 3:
The nozzle holder is a magnetic member, and an annular groove is provided on the outer periphery of a part thereof, that is, a portion located around the lower end of the fixed core, and the region having the annular groove is subjected to demagnetization or weakening treatment. The electromagnetic fuel injection valve according to aspect 1 or 2.
Embodiment 4:
The fuel introduction pipe is a non-magnetic member, the fixed core is a magnetic member, and the nozzle holder is a magnetic member, that is, a part located around the lower end of the fixed core is demagnetized or weakened. The electromagnetic fuel injection valve according to embodiment 1, wherein the fuel introduction pipe and the nozzle holder are thinner than the fixed core.
Embodiment 5:
The yoke has a cylindrical coil housing portion that houses the electromagnetic coil, a tapered throttle portion that follows the cylindrical coil housing portion, and a cylindrical yoke lower portion that follows the cylindrical coil housing portion, and the electromagnetic coil includes the coil housing portion. The inner periphery of the lower portion of the yoke is press-fitted into a part of the outer periphery of the nozzle holder, and the bottom surface of the bobbin of the electromagnetic coil and the tapered portion are positioned. An annular gap surrounded by the inner periphery of the nozzle holder and the outer periphery of the nozzle holder is an annular air gap for preventing magnetic flux leakage of the magnetic circuit for attracting the mover formed by the fixed core, the mover, the nozzle holder, and the yoke. The electromagnetic fuel injection valve according to any one of the first to fourth embodiments.
Embodiment 6:
The valve seat and the lower end of the fixed core define the stroke of the mover, and the outer periphery of the lower end of the fixed core is rounded as a guide curved surface of the press-fit, and the lower end surface of the fixed core The electromagnetic fuel injection valve according to any one of embodiments 1 to 5, wherein a hard coating is formed over the guide curved surface.
Embodiment 7:
The annular groove is provided in the outer periphery of the position where the said fixed core in the said nozzle holder is press-fitted, The said nozzle holder and the said fixed core are welded in the position of this annular groove in any one of Embodiment 1-6 The described electromagnetic fuel injection valve.
Embodiment 8:
In the nozzle holder, the portion that is press-fitted with the fixed core and the portion that houses the movable core have the largest diameter in the nozzle holder, and the valve body storage portion below it is narrowed down and extends downward, The electromagnetic fuel injection valve according to any one of Embodiments 1 to 7, wherein a seal ring is mounted on the outer periphery of the elongated valve body storage portion.

  As described above, according to this embodiment, the main body of the fuel injection valve is suitable for the above-described direct in-cylinder injection method, etc., while ensuring a sufficient magnetic circuit at a low cost while reducing the size and diameter. An electromagnetic fuel injection valve having excellent performance can be provided.

The longitudinal section of the fuel injection valve concerning one example of the present invention. The longitudinal cross-sectional view which decomposes | disassembles and shows a part of said fuel injection valve. The longitudinal cross-sectional view of the needle | mover of the said fuel injection valve. The expanded sectional view of the valve body and orifice plate which are used for the said Example. The top view and AA sectional drawing of the joint pipe used for the said Example. The top view and BB sectional drawing of an orifice plate used for the said Example. The partial expanded sectional view of the movable core and fixed core used for the said Example. The longitudinal cross-sectional view of the yoke used for the said Example. The top view, CC sectional drawing, and bottom view of a swirler used for the said Example. The exploded perspective view of the said Example. Explanatory drawing which shows the mounting state of the fuel injection valve which concerns on the said Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed core, 2 ... Electromagnetic coil, 3 ... Resin mold for coils (bobbin and coating), 4 ... Yoke, 5 ... Movable element, 7 ... Return spring, 14 ... Movable core, 15 ... Joint, 16 ... Valve body, 18 ... Nozzle holder, 19 ... Orifice plate, 41 ... Mass body, 50 ... Leaf spring (damper plate).

Claims (3)

A movable element having a valve body; a return spring that applies a spring load to the movable element on the valve seat side; an electromagnetic coil; and a magnetic circuit that magnetically attracts the movable element toward the valve opening side by excitation of the electromagnetic coil. In the electromagnetic fuel injection valve
The movable element has a movable core as an element of the magnetic circuit, the movable core and the valve body are connected via a joint having a spring function, and a leaf spring is incorporated in the movable element, An electromagnetic fuel injection valve characterized in that a mass body movable in the axial direction independently of the mover is disposed between a return spring and the leaf spring. The movable core has an upper shaft hole for introducing the mass body and a lower shaft hole having a diameter larger than that of the upper shaft hole, and the joint has a diameter smaller than that of the upper cylindrical portion. It consists of a pipe that is integrally formed with the lower cylinder,
The upper cylindrical portion is fitted into the lower shaft hole, the movable core and the joint are welded, and an inner diameter step surface between the upper shaft hole and the lower shaft hole of the movable core and the upper portion of the joint The leaf spring is interposed between the upper end surface of the cylindrical portion,
The upper part of the valve rod of the mover is welded to the lower cylindrical part of the joint,
The electromagnetic fuel injection valve according to claim 1, wherein a step between the upper cylindrical portion and the lower cylindrical portion of the joint has the spring function.   The electromagnetic fuel injection valve according to claim 1, wherein a hole through which fuel passes is provided in the joint.

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