JP4160594B2 - Electromagnetic fuel injection valve - Google Patents

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. In a conventional fuel injection valve, an electromagnetic coil and a yoke are arranged around a hollow cylindrical fixed core (center core), and a nozzle body in which a mover having a valve body is housed in a lower portion of the yoke that houses the electromagnetic coil. Is attached, and the mover is biased toward the valve seat by receiving the force of the return spring.

  As a conventional electromagnetic fuel injection valve, for example, one described in JP-A-10-339240 is known.

JP 10-339240 A

  However, the fuel described in Japanese Patent Laid-Open No. 10-339240 has not been sufficiently atomized. In this regard, a device provided with a fuel atomization mechanism including a fuel turning element upstream of the valve seat has been proposed, but has the following problems.

  In particular, 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 has been proposed in which a nozzle body provided in a lower part of a yoke is slender and long. When installing a long nozzle injector on the cylinder head, if the intake valve, intake pipe, and other parts are closely 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 part such as a connector mold or the like can be set apart so as not to interfere with other parts and the cylinder head, there is an advantage that the degree of freedom of attachment is high. However, as the nozzle body becomes longer, the nozzle driven by the movable core becomes longer, which makes it difficult to form the atomization mechanism of the nozzle portion.

  An object of the present invention is to provide an electromagnetic fuel injection valve that improves the atomization performance of a long nozzle type injector and simplifies the formation of the atomization mechanism.

  In order to achieve the above object, the present invention is such that the fuel swirl element attached upstream of the valve seat has a different polygonal shape on the outer periphery and a polygonal shape on the outer periphery of the surface on which the swirl groove is formed.

  ADVANTAGE OF THE INVENTION According to this invention, fuel atomization of a long nozzle type electromagnetic fuel injection valve can be improved. Moreover, the assembly to a nozzle part becomes easy.

Hereinafter, the configuration of an electromagnetic fuel injection valve according to an embodiment of the present invention will be described with reference to FIGS.
Initially, the whole structure of the electromagnetic fuel injection valve by this embodiment is demonstrated using FIG.
FIG. 1 is a longitudinal sectional view showing the overall configuration of an electromagnetic fuel injection valve according to an embodiment of the present invention.

  As shown in FIG. 1, the fuel injection valve 100 has a so-called top in which fuel flows in from the upper part of the injection valve body when the valve is opened, flows in the axial direction, and is injected from an orifice 16 provided at the lower end of the injection valve. The feed type is illustrated.

  The fuel passage in the axial direction of the fuel injection valve 100 is mainly composed of a fixed core 1 that is a hollow cylinder for introducing fuel, a hollow seal ring 19 having a flange at the bottom, and a hollow nozzle housing having a taper on the outer periphery. 13, the nozzle holder 14, and the orifice plate 16 with a valve seat are comprised from each element.

Here, the configuration of a part of the electromagnetic fuel injection valve according to the present embodiment will be described with reference to FIG.
FIG. 2 is a cross-sectional view of a part of an electromagnetic fuel injection valve according to an embodiment of the present invention. FIG. 2A is a cross-sectional view of the first example, and FIG. 2B is a cross-sectional view of another example.

  As shown in FIG. 2A, the upper end of the seal ring 19 is press-fitted to the fixed core 1 and welded at a location indicated by reference numeral W1. Further, a flange 19a is provided at the lower end portion of the seal ring 19, and is press-fitted and welded to the nozzle housing 13 at a location indicated by reference numeral W2. This welding is performed in the circumferential direction, and is joined in advance before the injection valve is assembled. That is, the seal ring 19 and the fixed core 1 and the flange 19 of the seal ring 19 and the nozzle housing 13 are fixed by press fitting. As described above, the circumferential welding between the two is performed because the fixed core 1, the seal ring 19 and the nozzle housing 13 form a fuel passage and prevent fuel leakage. It is. Therefore, compared with the case where the seal ring is fixed to the fixed core or the nozzle housing only by welding, the effect of thermal distortion due to welding can be reduced when welding for the seal ring after press-fitting. In the present embodiment, the inner diameter r2 of the seal ring 19 is larger than the inner diameter r1 of the nozzle housing 13 (r2> r1).

  Next, as shown in FIG. 1, the nozzle holder 14 is housed in the lower portion of the nozzle housing 13 via the stroke adjustment ring 17. A lower end portion of the nozzle housing 13 is fixed to the nozzle holder 14 by metal flow by plastic flow bonding. The plunger rod guide 18 is fixed inside the nozzle holder 14 by press fitting.

  As described above, the fixed core 1, the seal ring 13, the nozzle housing 13, the stroke adjusting ring 18, and the nozzle holder 14 are connected in series to form one fuel passage assembly.

  A cylindrical movable core 10, an elongated valve body 5, a joint pipe 11, a mass body 8, a return spring 7, a C ring pipe 6 and the like are incorporated in the fuel passage assembly. The valve body 5 includes a valve rod. The movable core 10, the valve body 5, and the joint pipe 11 are combined to form a movable element 12. The return spring 7 biases the mover 12 toward the valve seat 16a. The C-ring pipe 6 is a member that adjusts the spring force of the return spring 7 having a C-shaped cross section.

  The electromagnetic coil 2 is disposed on the outer periphery of the position where the fixed core 1 and the seal ring 19 are press-fitted and fitted, and the yoke 4 is disposed outside the electromagnetic coil 2. A plate housing 24 is press-fitted into the fixed core 1 and is welded to the upper end of the yoke 4 to form an assembly that houses the electromagnetic coil 2.

  When energizing the electromagnetic coil 2, the fuel injection valve 100 forms a magnetic circuit by the yoke 4, the fixed core 1, the movable core 10, the nozzle housing 13, and the plate housing 24, whereby the movable element 10 is connected to the return spring 7. A valve opening operation is performed by suctioning against the force. When the energization of the electromagnetic coil 2 is stopped, the movable element 12 comes into contact with the valve seat 16a by the urging force of the return spring 7 and the valve is closed as shown in FIG. In this example, the lower end surface of the fixed core 1 serves as a stopper for receiving the mover 12 during the valve opening operation.

Next, features of each component used in the fuel injection valve 100 of the present embodiment will be described.
The fixed core 1 is made of magnetic stainless steel, and is formed into an elongated hollow cylindrical shape by pressing and cutting. The hollow portion of the fixed core 1 serves as a fuel passage, and a C-ring pin 6 having a C-shaped cross section is press-fitted into the inner peripheral portion. The load of the return spring 7 is adjusted by the amount of press-fitting of the C ring pin 6. A fuel filter 25 is attached to the upper part of the C ring pin 6.

  The seal ring 19 is made of a nonmagnetic metal. A weak magnetic metal can also be used. As shown in FIG. 2A, the seal ring 19 has a flange portion 19a such as a lower end portion, and the cross-sectional shape is L-shaped. The fixed core 1 and the nozzle housing 13 are coupled via a seal ring 19. At this time, the positions of the lower end surface of the fixed core 1 and the upper end surface of the nozzle housing 13 are substantially the same.

  Here, the flange portion 19 a of the seal ring 19 is accommodated in a counterbore 13 b formed at the upper end portion of the nozzle housing 13. The height of the flange portion 19a and the depth of the counterbore 13b of the nozzle housing 13 are suitably about 1 to 2 mm. The flange portion 19a of the seal ring 19 blocks the magnetic flux generated in the coil 2, and the nozzle housing 13 In this structure, the movable core 10 and the fixed core 1 are efficiently guided. In the conventional structure, the nozzle housing 13 and the seal ring 19 are integrated, and the portion corresponding to the seal ring 19 is demagnetized, so that the magnetic flux is not sufficiently blocked. Since magnetic flux leakage occurred, the magnetic force was reduced. On the other hand, with the above-described structure, the magnetic flux can be concentrated on the nozzle housing 13, the movable core 10, and the fixed core 1, which are magnetic circuits, and the magnetic force necessary to attract the movable element 12 can be obtained. Can be generated. Therefore, the responsiveness at the time of valve opening can be improved.

  As shown in FIG. 2 (B), the seal ring 19c is made of a non-magnetic metal and a weak magnetic metal so as to have a hollow cylindrical shape, and the nozzle housing 13 and the fixed core 1 are also connected to attract the movable element 5. It is possible to prevent leakage magnetic flux from occurring in the magnetic circuit.

  Next, as shown in FIG. 2A, the nozzle housing 13 is made of a magnetic material and has a tapered portion on the outer peripheral portion. Further, the nozzle housing 13 includes counterbore 13b and 13c. The counterbore 13b is for accommodating the seal ring 19 and press-fitting, and the upper end surface of the seal ring flange portion 19b protrudes slightly from the upper end surface of the nozzle housing 13 in the press-fitted state. ing. This protrusion is to prevent assembling errors as much as possible during welding.

  After the seal ring 19 and the nozzle housing 13 are joined, the seal ring inner periphery 19b is cut and ground for press-fitting with the core 1. Thus, the diameter (r2) of the seal ring inner periphery 19b is set larger than the diameter (r1) of the nozzle housing inner periphery 13a, and the coaxiality between the seal ring inner diameter 19b and the nozzle housing 13 is finished with high accuracy by processing. As a result, the assembly error of the fixed core 1 can be prevented as much as possible, the operation of the injection valve 100 itself is stabilized, and the O-ring 21 and the backup ring 22 that are fuel seals are used within an appropriate usage range. Is possible.

  The seal ring 19 is welded and joined to the fixed core 1 and the nozzle housing 13 at two positions W1 and W2. The seal ring 19 passes through the injection valve main body 100 by sealing between the inner circumferences at the welded positions. Prevent fuel leaks.

  Further, the welded portion W1 can be welded to the thin wall portion of the seal ring 19, so that the heat energy required for welding can be saved, and the heat of the welding causes thermal deformation of the parts of the injection valve body. It can be prevented from occurring.

  The nozzle housing 13 includes a counterbore 13 c for housing a part of the nozzle holder 14 and the stroke adjustment ring 17, and has an annular groove 13 d necessary for coupling the nozzle housing 13 and the nozzle holder 14. .

  The nozzle housing 13 and the nozzle holder 14 shown in FIG. 1 are joined by pressing the end face of the nozzle housing 13 to plastically deform it and flowing it into two grooves 14a formed in the maximum outer diameter portion of the nozzle holder 14. By sealing the nozzle holder 14 and sealing the inner periphery with the metal flow, the leakage of fuel passing through the injection valve main body 100 is prevented.

  As shown in FIG. 2A, the nozzle housing 13 has a stepped portion 13e formed on the outer periphery of the upper end portion, and constitutes the hollow cylindrical yoke 4 and the inlay shown in FIG. By configuring the inlay, it is possible to prevent positional deviation when the yoke 4 and the nozzle housing 13 are joined by welding after the electromagnetic coil 2 is stored.

  Thereafter, the plate housing 24 is press-fitted in the axial direction until the plate housing 24 comes into contact with the upper end portion of the yoke 4, and the contact surface between the upper end portion of the yoke 4 and the plate housing 24 is joined by welding all around.

  Further, the pin terminal 20 of the electromagnetic coil is bent, and a resin mold 23 is applied to form a yoke.

Here, the assembly process of the yoke broom 52 will be described with reference to FIGS. 3 and 4.
FIG. 3 is an exploded perspective view showing the overall configuration of the electromagnetic fuel injection valve according to the embodiment of the present invention. FIG. 4 is an enlarged view of a yoke bumi 52 that is a component used in the electromagnetic fuel injection valve according to the embodiment of the present invention.

  A characteristic of the manufacturing process of the yoke bum 52 in the present embodiment is that each component is sequentially laminated from one direction. That is, in order to manufacture the yoke bum 52 shown in FIG. 4, the seal ring 19 is first press-fitted and welded from the upper direction of the nozzle housing 13. Next, the fixed core 1 is press-fitted and welded from above the seal ring 19. Next, the yoke 4 is inserted and welded from above the nozzle housing 13. Next, the electromagnetic coil 2 is housed on the inner peripheral side of the yoke 4 from above, and further, the plate housing 24 is press-fitted from the upper direction of the yoke 4 in the axial direction of the fixed core 1 and coupled by welding all around. To do. Further, the pin terminal 20 of the electromagnetic coil is bent and a resin mold 23 is applied, thereby forming a yoke bum 52 as shown in FIG.

  As described above, since the yoke buckle 52 according to the present embodiment is manufactured by sequentially stacking the components from one direction, the manufacture of the yoke buckle 52 can be easily performed.

  Next, as shown in FIG. 1, a groove 14c for attaching a seal member is provided on the outer periphery of the nozzle holder lower portion 14b, and a seal member 26, for example, a chip seal, is mounted in the groove 14c. The nozzle holder lower part 14b is longer than the conventional one and constitutes a so-called long nozzle part.

  Here, the configuration of the internal combustion engine using the fuel injection valve 100 will be described with reference to FIG.

  FIG. 5 is a cross-sectional view of an internal combustion engine using an electromagnetic fuel injection valve according to an embodiment of the present invention.

  The long nozzle portion 14b of the fuel injection valve 100 shown in FIG. 1 has a mounting density of the intake valve 101, the intake / exhaust valve drive mechanism 102, the intake pipe 103, and the like in the injection system directly provided on the cylinder head 106 of the engine 105. When it 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. Further, 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 26 provided on the outer periphery of the long nozzle portion 14b seals the outer periphery of the long nozzle portion 14b and the inner periphery of the insertion hole (on the cylinder head 106 side) to prevent engine combustion gas leakage. Since the combustion pressure receiving area can be reduced at the position, the seal member can be simplified and the cost can be reduced.

  As shown in FIG. 1, an orifice plate 16 and a fuel swirler (hereinafter referred to as “swirler”) 15 are provided at the lower end (tip) of the nozzle holder 14, and these members 14, 15, 16 are provided. Is formed by a separate member.

Here, the configuration of the orifice plate 16 will be described with reference to FIG.
FIG. 6 is an enlarged view showing the configuration of the orifice plate 15 and the tip of the mover 12 used in the electromagnetic fuel injection valve according to the embodiment of the present invention.

  As shown in FIG. 6, the orifice plate 16 is formed of, for example, a stainless steel disk-shaped tip, and an injection hole (orifice) 27 is provided at the center thereof, and a valve seat 16a is formed at the upstream portion thereof. ing.

  As shown in FIG. 1, the orifice plate 16 is attached to the inner circumference 14 d of the lower end of the nozzle holder 14 by press fitting. On the other hand, the swirler 15 is formed of a sintered alloy and is fitted to the inner periphery of the lower end of the nozzle holder 14.

Here, the configuration of the swirler 15 will be described with reference to FIG.
FIG. 7 is an enlarged view showing the configuration of the swirler 15 used in the electromagnetic fuel injection valve according to the embodiment of the present invention. 7A is a top view, FIG. 7B is a cross-sectional view taken along the line CC in FIG. 7A, and FIG. 7C is a bottom view.

  As shown in FIG. 7A, the swirler 15 is a chip having a shape close to an equilateral triangle and having R provided in three directions instead of the apex. In the center of the swirler 15, a central hole (guide) 27 for slidingly guiding the tip (valve element) of the mover 12 is provided. Further, on the upper surface of the swirler 15, guide grooves 28 for guiding the fuel to the chamfers 15 'on the three outer circumferences are formed radially outwardly with the annular groove 28' as the center.

  On the other hand, as shown in FIG. 7C, an annular step (flow path) 29 is formed on the outer peripheral edge of the lower surface of the swirler 15, and the fuel swirl between the annular flow path 29 and the central hole 27. A plurality of, for example, six passage grooves 30 are formed. The passage groove 30 is formed so as to be substantially tangential from the outer diameter side of the swirler 15 to the inner diameter, and is set so that a swirling force is generated in the fuel ejected from the passage groove 30 toward the lower end of the central hole 27. . The annular step 29 is provided for a fuel reservoir.

  Further, as shown in FIG. 7A, a three-sided chamfer 15 ′ is formed on the outer periphery of the swirler 15. The chamfer 15 ′ secures a fuel passage between the swirler 15 and the inner periphery of the nozzle holder 14 when the swirler 15 is fitted to the tip of the nozzle holder 14, and serves as a reference when processing the grooves 28 and 30. There is no. The R surface provided on the outer periphery of the swirler 15 is fitted to the inner periphery of the tip of the nozzle holder 14. When the shape of the swirler 15 is a shape close to a substantially equilateral triangle with R as described above, there is an advantage that a fuel flow rate can be sufficiently secured as compared with a chip with more polygonal sides.

  As shown in FIG. 1, an inner periphery (stepped inner periphery) 14 d with a receiving surface 14 e for mounting the swirler 15 and the orifice plate 16 is provided at the tip (one end of the fuel injection side) of the nozzle holder 14. The swirler 15 is fitted into the inner periphery of the nozzle holder so as to be received by the receiving surface 14e of the nozzle holder 14, while the orifice plate 16 is press-fitted and welded to the inner periphery 14d so as to press the swirler 15. . Reference numeral W3 indicates a welding position between the orifice plate 16 and the swirler 15 and is welded over the entire circumference of the orifice plate 15.

  By mounting the swirler 15 and the orifice plate 16 in this way, the swirler 15 is held between the receiving surface 14 e and the orifice plate 16. Since the upper surface of the swirler 15 is in pressure contact with the receiving surface 14e provided on the nozzle holder 14, as shown in FIG. 7, a fuel guide groove 28 is provided so that the fuel on the upstream side of the swirler passes through the groove 28 and the swirler 15 15 is arranged to flow through the fuel passage 31 on the outer periphery.

Here, the structure of the needle | mover 12 is demonstrated using FIG.
FIG. 8 is a side view of the mover 12 used in the electromagnetic fuel injection valve according to the embodiment of the present invention.

  As shown in FIG. 8, the movable core 10 and the valve body 5 in the mover 12 are connected via a joint 11 having a spring function. A leaf spring (damper plate) 9 is incorporated in the mover 12 between the movable core 10 and the joint 11.

  Further, as shown in FIG. 1, a mass body (weight, weight) that is movable in the axial direction independently of the mover 12 from the shaft hole f constituting the fuel passage of the fixed core 1 to the shaft hole provided in the movable core 10. 8 (which may be called a movable mass or the like) is arranged. The mass body 8 is located between the return spring 7 and the leaf spring 9. Therefore, the spring load of the return spring 7 is applied to the mover 12 via the mass body 8 and the leaf spring 9.

  As shown in FIG. 8, the movable core 10 has an upper shaft hole 10a for introducing a part of the mass body 8, and a lower shaft hole 10b having a diameter larger than that of the upper shaft hole 10a.

Here, the structure of the joint 11 is demonstrated using FIG.
FIG. 9 is an enlarged view showing the configuration of the joint 11 used in the electromagnetic fuel injection valve according to the embodiment of the present invention. FIG. 9A is a plan view of the joint 11, and FIG. 9B is a longitudinal sectional view of the joint 11.

  As shown in FIG. 9, the joint 11 is composed of an upper cylindrical portion 11a, a lower cylindrical portion 11c having a smaller diameter, and a tapered portion 11b formed integrally with the upper cylindrical portion 11a and the lower cylindrical portion 11c. It consists of a shaped pipe. The taper part 11b has a function as a leaf | plate spring.

  Then, as shown in FIG. 8, the upper cylindrical portion 11a is fitted into the lower shaft hole 10b of the movable core 10 and is welded to the movable core 10 at the position indicated by the symbol W5. The core 10 is coupled.

  A leaf spring 9 is interposed between the inner diameter step surface 10 c between the upper shaft hole 10 a and the lower shaft hole 10 b of the movable core 10 and the upper end surface of the upper cylindrical portion 11 a of the joint 11. The upper part of the valve element (valve rod) 5 of the mover is welded to the lower cylindrical portion 11c of the joint 11 at the position indicated by reference numeral W6 over the entire circumference.

Here, the configuration of the leaf spring 9 will be described with reference to FIG.
FIG. 10 is an enlarged view showing the configuration of the leaf spring 9 used in the electromagnetic fuel injection valve according to the embodiment of the present invention. FIG. 10A is a plan view of the leaf spring 9, and FIG. 10B is a longitudinal sectional view of the leaf spring 9.

  As shown in FIG. 10, the leaf spring 9 has an annular shape, and a portion indicated by reference numeral 51 on the inside thereof is a punched portion. By this punching, a plurality of elastic pieces 9a are projected inward, and these elastic pieces are formed. 9a is arrange | positioned at equal intervals in the circumferential direction. The lower end of the cylindrical movable mass body 8 is received by the elastic piece 9 a of the leaf spring 9.

  Moreover, as shown in FIG. 8, the thin part 10d is provided in the outer peripheral part of the lower side of the movable core 10 over the perimeter. Since the seal ring 19 shown in FIG. 1 is made of a non-magnetic material and does not constitute a magnetic circuit, the nozzle housing 13 and the movable core 10 located immediately below the lower end of the seal ring 19 Configure the magnetic circuit. Further, the lower end portion of the movable core 10 does not function as a magnetic circuit because the magnetic flux density decreases. A thin portion 10d is provided at the lower end of the movable core 10 that does not function as a magnetic circuit. Since the thin portion 10d does not function as a magnetic circuit, even if it has a thin shape, it does not affect the characteristics of the magnetic circuit. On the other hand, by reducing the thickness, the weight of the movable core 10 can be reduced. It is possible to reduce the weight of the movable element 12 which is a part and improve the responsiveness when the valve is opened.

  As described above, in the present embodiment, the leaf spring 9 receives the mass body (first mass body) 8, and the leaf spring portion (taper portion) 11 b of the joint 11 is the movable core (second mass body) 10. Therefore, the mass body and the leaf spring function (damper function) receiving it have a double structure.

  When the mover 5 collides with the valve seat 16a by the spring force of the return spring 7 during the closing operation of the fuel injection valve, the impact is first absorbed by the tapered portion 11b of the joint 11, and further, the mover 5 The rebound kinetic energy is absorbed by the inertia of the movable mass 8 and the elastic deformation of the leaf spring 9 to prevent the rebound. In particular, the double damper structure as described above sufficiently attenuates the impact energy when the valve body is closed, even in the case of a cylinder injection type fuel injection valve in which the spring load of the return spring 7 is large. Thus, the secondary injection accompanying the rebound can be effectively prevented.

  As shown in FIG. 9, the joint 11 together with the mass body 8 forms a fuel passage f, and the tapered portion 11b is provided with a plurality of holes 11d through which fuel passes to the nozzle holder 14 side.

  In this embodiment, the total cross-sectional area of the fuel passage hole 11d is set larger than the cross-sectional area of the fuel passage f defined inside the fixed core 1 and the mass body 8. When the inner diameter of the fuel passage f is 2φ, the total passage of the four fuel passage holes 11d with respect to the cross-sectional area (3.1 mm 2) of the fuel passage f is set by setting the inner diameter of the fuel passage hole 11d to 1.5φ. The area is (7.1 mm 2). Thereby, it is possible to reduce the pressure loss of the joint portion in the fuel passage, and it is possible to avoid an extreme flow restriction. As a result, the operation of the movable valve 12 can be stably performed, and furthermore, the operable fuel pressure as the fuel injection valve can be increased.

  In addition, the joint ring 11 has a shape with less streamline resistance by forming a cup-shaped pipe integrally formed with the tapered portion 11b between the upper cylindrical portion 11a and the lower cylindrical portion 11c. Accordingly, the fluid resistance when the mover 12 including the joint ring 11 moves can be reduced, and the responsiveness when the valve is closed is improved. The shape of the tapered portion 11b is not limited to the tapered shape, and may be a hemispherical shape.

  Further, as shown in FIG. 1, a part of the valve rod 12 serves as a movable guide surface. The inner periphery 18a of the plunger rod guide 18 serves as a guide surface for slidingly guiding the valve rod 12, and the inner periphery of the shaft hole 25 of the swirler 15 serves as a guide surface for slidingly guiding the valve rod 12. This constitutes a so-called two-point support guide system.

  The yoke 4 shown in FIG. 1 is obtained by pressing or cutting magnetic stainless steel, and has a cylindrical shape that accommodates the electromagnetic coil 2. The electromagnetic coil 2 is accommodated through the upper end of the yoke 4. The yoke lower portion 4c and a part of the outer periphery of the nozzle housing 13 are fitted, and the position of the electromagnetic coil 2 is defined by the seal ring upper end surface or the flange portion 19a.

  In the present embodiment, the stroke of the mover 12 is defined by the valve seat 16 a 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 10 collide with each other when the valve is closed. Therefore, as shown in FIG. Plating films 60 and 61 are formed. FIG. 11 is an enlarged view of main parts of the fixed core 1 and the movable core 10 used in the electromagnetic fuel injection valve according to the embodiment of the present invention.

  As shown in FIG. 11, the lower end portion 1 b of the fixed core 1 is provided with an R portion 1 c serving as a guide curved surface for press-fitting into the seal ring 19. The R portion 1c has a curvature of about R = 2.5 mm in the range indicated by the symbol L1 in FIG. As described above, the lower end portion 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 lower end portion of the fixed core 1 is formed in a tapered shape. it can. 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. Note that the hard coating treatment such as the chromium plating film 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 does not interfere with the press-fitting (add the thickness of the hard coating treatment). The fixed core lower end outer diameter is smaller than the outer diameter of the straight portion of the fixed core 1, and is rigid from the lower end surface of the fixed core 1 to the R portion (guide curved surface) 1 c (not exceeding the range of the symbol L 1). A coating is formed to provide wear and shock resistance.

  As shown in FIG. 6, the valve body 12 of the mover 5 has a tip that combines a spherical surface 12 a and a conical protrusion 12 b. The spherical surface 12a and the conical protrusion 12b have a discontinuous portion at a portion denoted by reference numeral 12c. The spherical surface 12a is seated on the valve seat 16a when the valve is closed. By making the surface in contact with the valve seat 16a into the spherical surface 12a, 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 12b has a function of reducing the dead volume of the orifice 27 and performing a fuel rectifying action. Further, when the discontinuous portion 12c 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.

  Next, the assembly process of the nozzle will be described with reference to FIG. The mover 12 shown in FIG. 1 is configured by press-welding the orifice plate 16 with the swirler 15 sandwiched between the tip of the nozzle holder 14. Into this, as shown in FIG. 8, the mover 12 assembled in advance is inserted. As shown in FIG. 4, the movable element 12 is formed with a chromium plating film 61 after being assembled. When the nozzle holder 14 is assembled with the pre-assembled yoke bumi 52 shown in FIG. 4, the stroke amount of the mover 12 can be easily set by defining the dimensions of the stroke adjusting ring 17. Thereafter, the nozzle housing 13 and the nozzle holder 14 are joined by metal flow. In the last step, the mass body 8, the return spring 7, the spring adjustment member 6, the fuel filter 31, the O-ring 32, and the backup ring 33 are incorporated.

Next, the response characteristics of the fuel injection valve according to the present embodiment will be described with reference to FIG.
FIG. 12 is a response characteristic diagram of the fuel injection valve according to the embodiment of the present invention. The horizontal axis in FIG. 12 indicates time (ms), and the vertical axis indicates the displacement (μm) of the mover.

  FIG. 12 shows the displacement of the mover when a valve closing command is given to the fuel injection valve 100 at time 0 ms. In the figure, symbol X indicates the response characteristic when the conventional fuel injection valve is closed, and it takes about 0.42 ms until the valve is closed. Here, the conventional fuel injection valve is obtained by demagnetizing a part of the nozzle holder. On the other hand, symbols Y and Z indicate response characteristics when the fuel injection valve according to the present embodiment is closed. The fuel injection valve indicated by the symbol Y is an example when the weight of the mover is reduced by providing a thin portion 10d at the lower end of the movable core 10 as shown in FIG. The response time is 0.405 ms, which is shorter than the conventional one indicated by the symbol X. Further, as shown in FIG. 3, the fuel injection valve indicated by Z is provided with a thin portion 10 d at the lower end portion of the movable core 10 to reduce the weight of the mover, and the independent non-return shown in FIG. 1. This is an example in which magnetic flux leakage is reduced by using a magnetic seal ring 19. The response time is 0.37 ms, which is shorter than the conventional one indicated by the symbol X.

  As described above, according to the present embodiment, as shown in FIG. 4, the fuel passage assembly is configured by integrally joining the nozzle housing 13 and the seal ring 19 by welding. Further, the assembly and the fixed core 1 are integrally coupled by welding. In this way, the fuel injection valve can be manufactured without impairing the assembly accuracy of the nozzle holder 13 and the fixed core 1. Further, the flange 19a is provided in the seal ring 19 so that the cross section is L-shaped. However, by adopting a non-magnetic or weak magnetic material, magnetic flux leakage of the magnetic circuit is minimized, and the magnetic flux is movable with the lower end of the fixed core 1. The magnetic attraction characteristics of the electromagnetic valve can be improved by flowing intensively with the core 10. Therefore, the responsiveness when the valve is closed can be improved.

  Further, when a part of the nozzle holder 14 is housed and coupled to the nozzle housing 13, the stroke can be determined to be a prescribed amount by way of the stroke adjusting ring 17 that regulates the stroke of the movable valve 12, thereby the fuel injection valve. It is possible to satisfy the required injection amount.

  Furthermore, since the impact and rebound of the valve body when the fuel injection valve is closed are effectively prevented by the double damper structure, secondary injection can be prevented more effectively than before.

  Moreover, because the yoke bukumi has a structure in which the components are sequentially stacked from the same direction, it is easy to assemble and can be easily automated.

  In the above description, the fuel injection valve of the in-cylinder injection method has been described, but the present invention can also be applied to a fuel injection valve disposed in the intake passage.

Next, the configuration of a fuel injection valve according to another embodiment of the present invention will be described with reference to FIGS. 13 and 14.
13 and 14 are longitudinal sectional views showing the structure of the mover of the fuel injection valve according to another embodiment of the present invention. In addition, the same code | symbol as FIG. 3 has shown the same part.

  A mover 12A shown in FIG. 13 includes a movable core 10, a damper plate 9, a joint 11, and a valve body 5A. The valve body 5 shown in FIG. 3 is a round bar, whereas the valve body 5A is constituted by a pipe. Thereby, the weight of the mover 12A can be reduced, and the responsiveness can be further improved. Since fuel also flows into the pipe-shaped valve body 5A, a fuel discharge hole is provided below the valve body 5A.

  Moreover, the needle | mover 12B shown in FIG. 14 is comprised from the movable core 10, the damper plate 9, the joint 11, and the valve body 5B. The valve body 5 shown in FIG. 3 has a round bar, while the valve body 5B has a split pin shape with a slit formed on the side. Thereby, the weight of the mover 12B can be reduced, and the responsiveness can be further improved. The valve body 5B can be easily manufactured by rounding the plate-like body so that a slit is formed on the side.

  A technique related to the present embodiment will be described below.

  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. In a conventional fuel injection valve, an electromagnetic coil and a yoke are arranged around a hollow cylindrical fixed core (center core), and a nozzle body in which a mover having a valve body is housed in a lower portion of the yoke that houses the electromagnetic coil. Is attached, and the mover is biased toward the valve seat by receiving the force of the return spring.

  As a conventional electromagnetic fuel injection valve, for example, as described in Japanese Patent Laid-Open No. 10-339240, in order to reduce the number of parts and improve assemblability, a single pipe formed of a composite magnetic material is used. It is known that a magnetic fuel connector part, a non-magnetic intermediate pipe part, and a valve body part are integrally formed by making them magnetic and making them non-magnetic only by induction heating or the like. In this electromagnetic fuel injection valve, a cylindrical fixed iron core is press-fitted into a 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, fuel connector, fixed core, movable core, valve body, and yoke, and the movable core is magnetically attracted to the fixed core. The nonmagnetic part is used to prevent a short circuit of magnetic flux between the fuel connector part and the valve body part.

  However, as described in Japanese Patent Application Laid-Open No. 10-339240, a non-magnetic intermediate pipe portion in the middle of a pipe cannot prevent sufficient magnetic flux leakage, and attracts the movable core due to magnetic flux leakage. However, there is a problem that the magnetic force is reduced and the responsiveness is lowered.

  In particular, 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 has been proposed in which a nozzle body provided in a lower part of a yoke is slender and long. When installing a long nozzle injector on the cylinder head, if the intake valve, intake pipe, and other parts are closely 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 part such as a connector mold or the like can be set apart so as not to interfere with other parts and the cylinder head, there is an advantage that the degree of freedom of attachment is high. However, as the nozzle body becomes longer, the nozzle driven by the movable core becomes longer and the weight also increases, so that a response delay due to a decrease in magnetic force becomes a significant problem.

  An object of the present embodiment is to provide an electromagnetic fuel injection valve with improved responsiveness.

(1) In order to achieve the above object, the present embodiment includes a mover having a valve body, an electromagnetic coil, and a magnetic circuit that magnetically attracts the mover toward the valve opening side by excitation of the electromagnetic coil. In the electromagnetic fuel injection valve, the magnetic circuit includes a hollow cylindrical fixed core constituting an axial fuel passage of the injection valve body, a hollow seal ring made of a nonmagnetic material or a weak magnetic material, and a hollow nozzle. The stator is composed of a housing and a movable core that constitutes a part of the mover, and the stator core and the nozzle housing are coupled via the seal ring.
With this configuration, magnetic flux leakage can be reduced, magnetic force can be improved, and responsiveness can be improved.

  (2) In the above (1), preferably, the seal ring has a flange at a lower portion thereof, and a lower portion of the fixed core is press-fitted into an upper portion of the seal ring, and is fuel-sealed by welding. The flange portion of the ring is press-fitted into the inlay portion at the upper end portion of the nozzle housing, and is sealed by welding.

  (3) In the above (2), preferably, a rounded portion or a taper portion serving as a guide curved surface for press-fitting into the seal ring is provided on the outer periphery of the lower end of the fixed core, and the rounded portion extends from the lower end surface of the fixed core. A hard film formed over the portion or the taper portion is provided.

  (4) In the above (2), preferably, the seal ring is configured such that a contact surface between the movable element and the fixed core is provided in the vicinity of an upper end portion of a flange portion of the seal ring.

  (5) In the above (1), preferably, the seal ring has a gradually enlarged diameter in the outer circumferential direction at the lower end portion of the inner diameter, and the inner diameter of the lower end portion of the seal ring is larger than the inner diameter of the nozzle housing. It is a big one.

  (6) In the above (1), preferably, a thin-walled portion is provided below the movable core.

  (7) In the above (1), preferably, the mover is composed of the movable core, a valve body, and a joint connecting the movable core and the valve body, and the joint includes an upper tube portion. And a lower cylindrical portion having a smaller diameter than the upper cylindrical portion, and a tapered or spherical connecting portion having a small streamline resistance connecting the upper cylindrical portion and the lower cylindrical portion.

  (8) In the above (7), preferably, the connecting portion of the joint has a spring property.

  (9) In the above (8), preferably, a leaf spring disposed between the movable core and the joint is provided.

(10) In the above (7), preferably, the joint connecting portion is provided with a hole through which fuel passes, and the total cross-sectional area of the hole is equal to that of the shaft hole through which the fuel provided in the mover passes. It is larger than the cross-sectional area.

It is a longitudinal section showing the whole electromagnetic fuel injection valve composition by one embodiment of the present invention. 1 is a partial cross-sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention. It is a disassembled perspective view which shows the whole structure of the electromagnetic fuel injection valve by one Embodiment of this invention. It is an enlarged view of the yoke bum 52 which is a component used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is sectional drawing of the internal combustion engine using the electromagnetic fuel injection valve by one Embodiment of this invention. It is an enlarged view which shows the structure of the front-end | tip part of the orifice plate 15 and the needle | mover 12 which are used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is an enlarged view which shows the structure of the swirler 15 used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is a side view of the needle | mover 12 used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is an enlarged view which shows the structure of the joint 11 used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is an enlarged view which shows the structure of the leaf | plate spring 9 used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is the principal part enlarged view of the fixed core 1 and the movable core 10 which are used for the electromagnetic fuel injection valve by one Embodiment of this invention. It is a response characteristic figure of a fuel injection valve by one embodiment of the present invention. It is a longitudinal cross-sectional view which shows the structure of the needle | mover of the fuel injection valve by other embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the needle | mover of the fuel injection valve by other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed core 2 ... Electromagnetic coil 3 ... Resin mold for coils 4 ... Yoke 12 ... Movable element 7 ... Return spring 8 ... Mass body 9 ... Leaf spring (damper plate),
10 ... movable core 11 ... joint 14 ... nozzle holder 16 ... orifice plate

Claims (6)

A valve seat member having a fuel nozzle and a valve seat portion formed upstream thereof;
A fuel injection valve provided with a swirling element disposed in a fuel chamber having a cylindrical peripheral wall upstream of the valve seat member and imparting a swirling force to the fuel;
The swivel element has a first surface facing the valve seat member and a second surface opposite to the first surface;
The swivel element has a through-hole formed between the first surface and the second surface at the center,
The side surface of the swivel element has three planes and three curved surfaces alternately arranged at substantially equal intervals around the side surface,
A polygonal protruding surface having a plurality of sides is formed on the first surface,
The projecting surface is provided with a fuel turning groove that extends from each side of the projecting surface to the through hole and opens at a position offset from the center.
Furthermore, the fuel injection valve which has a radiation groove which extends in the radial direction from the said through-hole in the 2nd surface, and opens to the side part formed in the said plane. The fuel injection valve according to claim 1, wherein
A polygon having a plurality of sides formed on the first surface is a hexagon;
A fuel injection valve in which three sides formed in one jump of the hexagon are formed in parallel with the three planes of the swivel element . The fuel injection valve according to claim 1, wherein
The fuel injection valve has a larger diameter between a circle in which the side surface of the swivel element is inscribed and a circle in which the side surface of the polygonal projecting surface formed on the first surface is inscribed in the circle in which the side surface of the swivel element is inscribed . The fuel injection valve according to claim 1, wherein
The fuel chamber having the cylindrical peripheral wall is formed at a tip portion of the fuel injection valve. The fuel injection valve according to claim 1, wherein
A fuel injection valve in which a diameter of a circle in which a side surface of the swivel element is inscribed and a cylindrical peripheral wall of the fuel chamber is larger than a diameter of the cylindrical peripheral wall of the fuel chamber. The fuel injection valve according to claim 1, wherein
A fuel injection valve in which the through hole guides the axial movement of the valve body.

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