JP3999777B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve mainly used in a fuel supply system of an internal combustion engine. In particular, the valve seat and a valve housing in which a valve hole penetrating the center of the valve seat is formed in a front end wall are provided in cooperation with the valve seat. The present invention relates to an improvement in a fuel injection valve that accommodates a valve body that opens and closes a valve hole and welds an injector plate having a fuel injection hole communicating with the valve hole to a front end wall of the valve housing.

Such a fuel injection valve is already known as disclosed in Patent Document 1 below.
JP-A-4-50464

  Conventionally, in such a fuel injection valve, when the injector plate is welded to the front end wall of the valve housing, the injector plate formed in a dish shape is fitted to the front end portion of the valve housing, or is attached to the front end surface of the valve housing. The disk-shaped injector plate is fitted into the formed circular recess, and the injector plate is positioned in the valve housing. However, in any positioning method, there is a positioning error due to the fitting gap of the injector plate with respect to the valve housing, so that the relative position of the fuel injection hole formed in the injector plate with respect to the valve hole in the valve housing is somewhat out of order. Will occur.

  The present invention has been made in view of such circumstances, and enables accurate welding of the injector plate to the valve housing so that the injector plate can be accurately temporarily fixed to the front end wall of the valve housing. An object of the present invention is to provide a fuel injection valve capable of stabilizing the relative position of the injection hole with respect to the valve hole of the valve housing without any error.

  In order to achieve the above-mentioned object, the present invention provides a valve body that opens and closes a valve hole in cooperation with the valve seat in a valve housing in which a valve hole penetrating the center of the valve seat is formed in the front end wall. In a fuel injection valve in which an injector plate having a fuel injection hole communicating with the valve hole is welded to the front end wall of the valve housing, the valve hole is surrounded on the outer surface of the front end wall of the valve housing. A circular recess is formed, and an injector plate having a basic shape of a smaller diameter disk is fitted into the recess, and the injector plate is pushed and bent to one side of the inner peripheral surface of the recess. However, the first feature is that a temporary fastening claw for pressing the injector plate to the other side of the inner peripheral surface of the concave portion is integrally formed, and this injector plate is liquid-tightly welded to the ceiling surface of the concave portion.

  In addition to the first feature of the present invention, the relative position of the fuel injection hole to the center of the injector plate is offset to the temporary pawl side by the difference between the inner diameter of the recess and the outer diameter of the injector plate. Is the second feature.

  Furthermore, in addition to the first or second feature, the present invention has a third feature that the injector plate is formed with notches on both sides of the temporary fastening claw for extending the effective length of the temporary fastening claw.

  According to the first feature of the present invention, the injector plate is pushed into the circular recess on the front end surface of the valve housing, and the temporary stop claw of the injector plate is deformed and locked to the inner peripheral surface of the recess. In this case, the injector plate can be temporarily fixed to the recess, and at that time, the injector plate is held in a state of being shifted to one side of the recess by the deformation reaction force of the temporary fixing claw. The position of the fuel injection hole drilled in can be always kept at a fixed position, and therefore the injector plate can be easily and accurately welded to the ceiling surface of the recess in this state.

  Further, according to the second feature of the present invention, when the injector plate is temporarily fixed, the distance between the one side of the recess and the difference between the inner diameter of the recess and the outer diameter of the injector plate is estimated. Since the relative position of the hole with respect to the center of the injector plate is offset to the temporary stopper claw side, the fixed position of the fuel hole with respect to the center line of the valve hole can always be stabilized. The position and direction of the spray foam can always be stabilized.

  Furthermore, according to the third feature of the present invention, the difference between the inner diameter of the recess and the outer diameter of the injector plate is reduced, and when the stopper is temporarily fixed to the recess of the injector plate, the lateral displacement of the injector plate is reduced as much as possible. The temporary fixing of accuracy can be performed, and at the same time, a sufficient deformation allowance can be given to the temporary fixing claws to enhance the temporary fixing function.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention, FIG. 2 is an enlarged view of part 2 of FIG. 1, FIG. 3 is a view taken along arrow 3 of FIG. FIG.

  1 and 2, a valve housing 2 of an electromagnetic fuel injection valve I is coaxially coupled to a cylindrical valve seat member 3 having a valve seat 8 at a front end and a rear end portion of the valve seat member 3. The magnetic cylinder 4, the nonmagnetic cylinder 6 coaxially coupled to the rear end of the magnetic cylinder 4, the fixed core 5 coaxially coupled to the rear end of the nonmagnetic cylinder 6, and the fixed core 5 and a fuel inlet tube 26 coaxially provided at the rear end.

  The valve seat member 3 has a connecting tube portion 3a protruding from the outer peripheral surface to the magnetic cylinder 4 side with an annular shoulder portion 3b at the rear end portion. The valve seat member 3 and the magnetic cylindrical body 4 are coaxially and liquid-tightly coupled to each other by press-fitting into the inner peripheral surface of the front end portion and bringing the front end surface of the magnetic cylindrical body 4 into contact with the annular shoulder 3b. The magnetic cylindrical body 4 and the nonmagnetic cylindrical body 6 face each other and face each other and are connected to each other coaxially and liquid-tightly by laser beam welding.

  The valve seat member 3 includes a cylindrical guide hole 9, a conical valve seat 8 connected to the front end of the guide hole 9, and a valve hole 7 penetrating through the central portion of the valve seat 8. A circular recess 45 concentrically surrounding the valve hole 7 is formed on the front end surface of the valve seat member 3, and the injector plate 10 is temporarily fixed to the recess 45 and welded to the valve seat member 3. The temporary fixing structure will be described in detail later. The injector plate 10 is provided with a plurality of annular fuel injection holes 11, 11... Concentrically surrounding the center line O of the valve hole 7.

  The valve seat 8 of the valve seat member 3 is formed in a conical shape. Between the valve seat 8 and the valve hole 7, the fuel that has passed through the valve seat 8 is collected and guided to the valve hole 7. A collective recess 35 is formed.

  Further, a flat fuel diffusion chamber that extends radially outward from the valve hole 7 and diffuses the fuel that has passed through the valve hole 7 radially outward is provided between the opposing surfaces of the valve seat member 3 and the injector plate 10. 36 is formed. The fuel diffusion chamber 36 is formed as a recess in the front end surface of the valve seat member 3 in the illustrated example. The injector plate 10 is provided with a plurality of fuel injection holes 11, 11... That open to the fuel diffusion chamber 36 at positions radially away from the valve hole 7. Therefore, the valve hole 7 and each fuel injection hole 11 communicate with each other via the fuel diffusion chamber 36.

  A hollow cylindrical fixed core 5 is press-fitted into the inner peripheral surface of the nonmagnetic cylindrical body 6 from the rear end side thereof, whereby the nonmagnetic cylindrical body 6 and the fixed core 5 are coaxially coupled to each other. At this time, a portion that does not fit with the fixed core 5 remains at the front end portion of the nonmagnetic cylindrical body 6, and the valve assembly V is accommodated in the valve housing 2 extending from the portion to the valve seat member 3.

  The valve assembly V is connected to the valve rod portion 17 including a valve portion 16 that opens and closes with respect to the valve seat 8 and a valve rod portion 17 that supports the valve portion 16, and is connected to the valve rod portion 17. It consists of a movable core 12 straddling the cylindrical body 6 and inserted into them and confronted with the fixed core 5 coaxially. The valve rod portion 17 is formed to have a smaller diameter than the guide hole 9, and the journal portion 17 a that protrudes radially outward at the outer periphery thereof and is slidably supported on the inner peripheral surface of the guide hole 9. Are integrally formed. In addition, a journal portion 17b that is slidably supported on the inner peripheral surface of the magnetic cylindrical body 4 is formed on the outer periphery of the movable core 12.

  The valve assembly V includes a vertical hole 19 that ends from the rear end surface of the movable core 12 before the valve portion 16, and a plurality of first horizontal holes 20 a that communicate with the outer peripheral surface of the movable core 12. A plurality of second lateral holes 20b are provided to communicate the vertical hole 19 with the outer peripheral surface of the valve rod part 17 between the journal part 17a and the valve part 16. At that time, an annular spring seat 24 facing the fixed core 5 is formed in the middle of the vertical hole 19.

  The fixed core 5 has a vertical hole 21 that communicates with the vertical hole 19 of the movable core 12, and a fuel inlet cylinder 26 that communicates internally with the vertical hole 21 is integrally connected to the rear end of the fixed core 5. The fuel inlet cylinder 26 is composed of a reduced diameter portion 26a connected to the rear end of the fixed core 5 and a subsequent enlarged diameter portion 26b, and a slotted pipe shape press-fitted into the vertical hole 21 from the reduced diameter portion 26a. A valve spring 22 for biasing the movable core 12 toward the valve closing side of the valve body 18 is provided between the retainer 23 and the spring seat 24. At that time, the set load of the valve spring 22 is adjusted by the depth of fitting of the retainer 23 into the vertical hole 21. A fuel filter 27 is mounted in the expanded diameter portion 26b, and a seal member 49 is mounted on the outer periphery of the expanded diameter portion 26b.

  The fixed core 5 is made of a ferrite-based high hardness magnetic material. On the other hand, a collar-like stopper element 14 surrounding the valve spring 22 is embedded in the movable core 12 on the suction surface opposite to the suction surface of the fixed core 5. The stopper element 14 has its outer end slightly protruded from the suction surface of the movable core 12 and is normally opposed to the suction surface of the fixed core 5 with a gap corresponding to the valve opening stroke of the valve body 18. The

  A coil assembly 28 is fitted to the outer periphery of the valve housing 2 so as to correspond to the fixed core 5 and the movable core 12. The coil assembly 28 includes a bobbin 29 fitted to the outer peripheral surface from the rear end portion of the magnetic cylindrical body 4 to the fixed core 5 and a coil 30 wound around the bobbin 29. The front end of the coil housing 31 that surrounds 28 is welded to the outer peripheral surface of the magnetic cylindrical body 4, and the rear end is welded to the outer peripheral surface of the yoke 5 a that protrudes in a flange shape from the outer periphery of the rear end portion of the fixed core 5. The coil housing 31 has a cylindrical shape, and a slit 31a extending in the axial direction is formed on one side.

  A part of the magnetic cylinder 4, the coil housing 31, the coil assembly 28, the fixed core 5, and the front half of the fuel inlet cylinder 26 are embedded in a synthetic resin cylindrical mold part 32 by injection molding. At that time, the mold portion 32 is filled into the coil housing 31 through the slit 31a. In addition, a coupler 34 projecting to one side is integrally formed at an intermediate portion of the mold portion 32 via an annular reinforcing collar portion 32a, and this coupler 34 holds an energization terminal 33 connected to the coil 30. To do. Further, the reinforcing collar 32a contributes to the reinforcement of the base of the coupler 34.

  Thus, when the coil 30 is demagnetized, the valve assembly V is pressed forward by the urging force of the valve spring 22, and the valve body 18 is seated on the valve seat 8. In this state, the fuel pumped from the fuel pump (not shown) to the fuel inlet cylinder 26 passes through the pipe-like retainer 23, the vertical hole 19 of the valve assembly V, and the first and second horizontal holes 20a and 20b. 3 is put on standby and used for lubrication around the journal portions 17a and 17b of the valve assembly V.

  When the coil 30 is energized by energization, the magnetic flux generated by the coil 30 sequentially travels through the fixed core 5, the coil housing 31, the magnetic cylindrical body 4, and the movable core 12, and the movable core 12 of the valve assembly V is set to the valve spring 22 by the magnetic force. Since the valve portion 16 of the valve body 18 is separated from the valve seat 8 of the valve seat member 3 against the load, the high pressure fuel in the valve seat member 3 passes through the valve seat 8. Thereafter, the fuel collecting recess 35 is guided to the valve hole 7, the flow is reversed at the valve hole 7, the gas is transferred to the fuel diffusion chamber 36, diffused outward in the radial direction, and the plurality of fuel injection holes 11 of the injector plate 10. , 11..., And fuel spray foam F can be formed.

  In FIG. 1, the end face on the valve seat member 3 side of the reinforcing collar 32 a for reinforcing the coupler 34 formed in the middle of the mold part 32 is an annular first seal seat surface 38. The end face on the valve seat member 3 side is also an annular second seal seat face 39. Accordingly, the first seal seat surface 38 has a larger diameter than the second seal seat surface 39, and the axial distance from the first seal seat surface 38 to the front end surface of the valve seat member 3 is the second seal seat surface 39. To the front end face of the valve seat member 3 is longer than the axial distance. A large-diameter seal ring 40 or a small-diameter seal ring 41 is selectively attached to the first and second seal seating surfaces 38 and 39 according to the attachment site of the electromagnetic fuel injection valve I. Yes.

  Now, with reference to FIG. 2 and FIG. 3, a temporary fixing structure of the injector plate 10 to the circular recess 45 on the front end face of the valve seat member 3 will be described.

  The injector plate 10 is basically a disc having an outer diameter d smaller than the inner diameter D of the recess 45, and a temporary fixing claw 46 is integrally projected on one side thereof. Is formed such that the length S from the tip thereof to the other side surface of the injector plate 10 on the opposite side is longer than the inner diameter D of the recess 45. The injector plates 10 on both sides of the temporary fastening pawl 46 are provided with a pair of notches 47 and 47 that extend the effective length of the temporary fastening pawl 46. The notches 47 and 47 may be U-shaped, but in the illustrated example, they are formed in a planar shape to facilitate processing.

  Thus, when the injector plate 10 is temporarily fixed to the valve seat member 3, the end of the injector plate 10 opposite to the temporary fixing claw 46 is brought into contact with a part of the inner peripheral surface of the recess 45. In the state (the chain line state in FIG. 2), the injector plate 10 is pushed into the recess 45. Then, the injector plate 10 can turn around the contact portion with the inner peripheral surface of the recess 45 as a fulcrum, and can be brought into close contact with the ceiling surface of the recess 45. Meanwhile, the temporary fastening pawl 46 is pushed and bent by the inner peripheral surface of the recess 45 and is locked to the inner peripheral surface, and the deformation reaction force presses the injector plate 10 toward the contact portion side. Thus, the injector plate 10 is always on the opposite side of the temporary stop claw 46 with respect to the center line O of the valve hole 7 and the recess 45 by a difference (D−d) between the outer diameter d of the injector plate 10 and the inner diameter of the recess 45. Temporarily secured to the recess 45 in a state of being aligned.

  At that time, in order to maintain the concentric relationship between the center Y of the fuel nozzle holes 11, 11... In the annular array of the injector plate 10 and the center line O of the valve hole 7, the center Y of the fuel nozzle holes 11, 11. Is offset from the center O ′ of the injector plate 10 toward the temporary pawl 46 by the difference (D−d) between the outer diameter d of the injector plate 10 and the inner diameter of the recess 45.

  After temporarily fixing the injector plate 10 to the recess 45, the injector plate 10 is liquid-tightly coupled to the ceiling surface of the recess 45 by a welded portion 37 formed in an annular shape so as to surround the diffusion chamber 36 by laser welding. .

  As described above, the injector plate 10 is pushed into the circular recess 45 on the front end face of the valve seat member 3 to deform the temporary fixing claw 46 of the injector plate 10 and lock it to the inner peripheral surface of the recess 45. The injector plate 10 can be temporarily fixed to the recess 45 by an extremely simple operation, and at this time, the injector plate 10 is shifted to one side of the recess 45 by the deformation reaction force of the temporary fixing claw 46. Therefore, the positions of the fuel injection holes 11 formed in the injector plate 10 can always be held at a fixed position. Therefore, the injector plate 10 can be easily and accurately welded to the ceiling surface of the recess 45 in this temporarily fixed state.

  In particular, considering the distance (D−d) between the distance at which the injector plate 10 is shifted to one side of the recess 45, that is, the difference (D−d) between the inner diameter of the recess 45 and the outer diameter d of the injector plate 10, 11... The relative position of the group to the center O ′ of the injector plate 10 is offset by the difference (D−d) toward the temporary pawl 46, so that the fuel nozzles 11, 11. Can always be aligned with the center line O of the valve hole 7 and the recess 45, and the position and direction of the fuel spray foam F can be always stabilized.

  In addition, the injector plate 10 is provided with notches 47 and 47 that extend the effective length of the temporary fastening pawl 46 on both sides of the temporary fastening pawl 46, so that the difference between the inner diameter D of the recess 45 and the outer diameter d of the injector plate 10 ( D-d) can be reduced, and when the temporary fixing of the injector plate 10 to the recess 45, the lateral displacement of the injector plate 10 can be reduced as much as possible to perform high-accuracy temporary fixing. A sufficient deformation allowance can be given to the temporary fixing function.

  3 and 4, reference numeral 48 denotes a notch for preventing wrong assembly of the front and back formed at a position approximately 90 ° on the outer periphery of the injector plate 10 on the right or left side in a predetermined direction on the right or left side. It is a mark. That is, when the injector plate 10 is fitted in the recess 45, the operator places the mark 48 in a predetermined direction with respect to the temporary fixing claw 46 so that the surface of the injector plate 10 is always outward in the fuel injection direction. Can be directed.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, in the above-described embodiment, the number of the temporary fastening claws 46 on the injector plate 10 is one, but a plurality of provisional pawls 46 may be provided on one half circumference side of the injector plate 10.

The longitudinal cross-sectional view of the electromagnetic fuel injection valve which concerns on the Example of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a view taken in the direction of arrow 3 in FIG. 2. The top view of an injector plate single-piece | unit.

Explanation of symbols

I ... Fuel injection valve O ... Valve hole and recess center line O '... Injector plate center 2 ... Valve housing 7 ... Valve hole 8 ... ··· Valve seat 10 ··· Injector plate 11 ··· Fuel injection hole 18 ··· Valve body 45 ··· Recess 16 ··· Temporary claw 47 ··· Notch

Claims (3)

A valve housing (2) in which a valve seat (8) and a valve hole (7) penetrating the center of the valve seat (8) are formed in the front end wall are formed in cooperation with the valve seat (8). The injector plate (10) having a fuel injection hole (11) communicating with the valve hole (7) is welded to the front end wall of the valve housing (2). In the fuel injection valve
A circular recess (45) surrounding the valve hole (7) is formed in the outer surface of the front end wall of the valve housing (2), and an injector plate (basic shape of a smaller diameter disk) is formed in the recess (45). 10) is fitted, and the injector plate (10) is pushed and bent to one side of the inner peripheral surface of the recess (45), and the injector plate (10) is held on the inner peripheral surface of the recess (45). A fuel injection valve characterized in that a temporary fastening claw (46) that is pressed to the other side is integrally formed, and this injector plate (10) is liquid-tightly welded to the ceiling surface of the recess (45). The fuel injection valve according to claim 1, wherein
The center (O ′) of the injector plate (10) of the fuel injection hole (11) by the difference (D−d) between the inner diameter (d) of the recess (45) and the outer diameter (D) of the injector plate (10). The fuel injection valve is characterized in that the relative position of the fuel injection valve is offset toward the temporary fastening claw (46). The fuel injection valve according to claim 1 or 2,
A fuel injection valve characterized in that notches (47, 47) for extending the effective length of the temporary fastening claws (46) are formed on both sides of the temporary fastening claws (46) in the injector plate (10).

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