JP3987039B2 - 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, and in particular, a valve seat member having a valve seat and a valve hole penetrating the central portion thereof, and the valve seat in cooperation with the valve seat. A valve body that opens and closes a hole; and an injector plate that has a plurality of fuel injection holes and is welded to an outer end surface of the valve seat member, the valve hole and the fuel injection hole between the valve seat member and the injector plate during an improvement of a fuel injection valve having a fuel passage Ru is communicating.

Such a fuel injection valve is already known as disclosed in, for example, Patent Document 1 below.
JP 2002-130074 A

Incidentally, the one disclosed in Patent Document 1, a fuel passage Ru is communicating between the valve hole and the fuel injection hole, since formed as recesses in the end face of the valve seat member, the formation of recesses in the end face of the valve seat member Therefore, it is difficult to reduce manufacturing costs. Moreover, since the injector plate consists of a single flat plate as a whole, a relatively thick plate is used so that it does not bend due to the fuel pressure in the fuel passage. to require a large amount of heat input during welding the outer end face of the member, which is not only a hindrance to the improvement of productivity, there is a possibility of causing thermal strain in the valve seat member.

  The present invention has been made in view of such circumstances, and by making the injector plate press-molded, the cutting of the fuel passage can be eliminated, and at the same time, the rigidity of the injector plate is enhanced and its thickness is reduced. Therefore, it is possible to reduce the heat input when the injector plate is welded to the outer end surface of the valve seat member, to improve productivity, and to provide a fuel injection valve that can prevent thermal distortion of the valve seat member. With the goal.

In order to achieve the above object, the present invention comprises a valve seat member having a valve seat and a valve hole penetrating the central portion thereof, a valve body for opening and closing the valve hole in cooperation with the valve seat, An injector plate having a fuel injection hole and welded to an outer end surface of the valve seat member; and an annular upper wall portion joined to the valve seat member, and an inner wall of the upper wall portion. A vertical wall portion projecting from the peripheral end to the opposite side of the valve seat member, and a flat fuel passage extending radially inward from the tip of the vertical wall portion and communicating with the valve hole between the valve seat member In the fuel injection valve, the inner peripheral surface of the vertical wall portion is formed by integrally connecting a bottom wall portion that defines a plurality of fuel injection holes to communicate the inside and outside of the bottom wall portion. and pruning by being sheared by the press-molding so as to stand substantially vertically from the bottom wall portion Together to such a cliff face to be formed, the outer peripheral surface of the vertical wall portion, the so formed as small as a ruthenate over tapered surface toward the center portion of the injector plate, by compression molding by press molding The first feature is that the vertical wall portion and the bottom wall portion are formed at the same time .

  Note that the tapered surface includes one in which the generatrix is a straight line, a curved line or a multi-stage bent line.

  In addition to the first feature, the present invention provides the second feature in that the vertical wall surface and the tapered surface of the vertical wall portion are arranged such that the axial extension line of the vertical wall surface intersects the tapered surface. And

According to the first feature of the present invention, the fuel passage can be easily formed by press-molding the injector plate, and the manufacturing is simplified as compared with the case where the fuel passage is cut in the valve seat member. , Cost can be reduced.

In addition, in the injector plate, the inner peripheral surface of the vertical wall is shear-formed by press molding, so that it is a steep wall so that it stands up substantially vertically from the bottom wall. The shape and volume of the fuel passage can be freely set by selection.

Also, the upper end and lower end of the above-mentioned wall face are prone to sag and cracks due to shear molding. When the outer peripheral surface of the vertical wall section is tapered by compression molding by press molding , Filling the lower end with the material suppresses the occurrence of sag and cracks and can form an exact wall surface, improving the dimensional accuracy of the fuel passage and contributing to the stabilization of fuel spray characteristics. obtain.

  In addition, since the vertical wall part is greatly hardened by work, and the upper wall part and the bottom wall part having a step are integrally connected, the rib effect is exerted greatly, and the rigidity of the injector plate is improved. This effectively enhances the thickness of the valve seat member. Therefore, it is possible to reduce the heat input when the injector plate is welded to the outer end surface of the valve seat member, thereby improving the productivity and improving the heat of the valve seat member. Distortion can be prevented.

  Further, according to the second feature of the present invention, when the injector plate is press-molded, the material can be more effectively filled toward the upper end and the lower end of the wall surface. It can be formed accurately.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine 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 3-3 in FIG. It is explanatory drawing of the press molding process of the injector plate of the said fuel injection valve.

  First, in FIGS. 1 and 2, a casing 1 of an electromagnetic fuel injection valve I for an internal combustion engine is connected to a cylindrical valve housing 2 (magnetic body) and a front end portion of the valve housing 2 in a liquid-tight manner. It comprises a bottom cylindrical valve seat member 3 and a cylindrical fixed core 5 which is liquid-tightly coupled with an annular spacer 4 sandwiched between the rear end of the valve housing 2.

  The annular spacer 4 is made of a non-magnetic metal such as stainless steel, and the valve housing 2 and the fixed core 5 are abutted against both end faces of the annular spacer 4 and are welded in a liquid-tight manner. A laser beam is used for the welding. .

  A first fitting tube portion 3a and a second fitting tube portion 2a are formed at opposite ends of the valve seat member 3 and the valve housing 2, respectively. The first fitting cylinder 3a is press-fitted together with the stopper plate 6 into the second fitting cylinder 2a, and the stopper plate 6 is sandwiched between the valve housing 2 and the valve seat member 3. After that, by performing laser welding or beam welding over the entire circumference of the corner sandwiched between the outer peripheral surface of the first fitting tube portion 3a and the end surface of the second fitting tube portion 2a, the valve housing 2 and the valve seat member 3 Are liquid-tightly coupled to each other.

  The valve seat member 3 includes a conical valve seat 8 having a downstream end opened at a front end surface thereof, a valve hole 10 penetrating through a central portion of the valve seat 8 and opened at an outer end surface of the valve seat member 3, A cylindrical guide hole 9 connected to the upstream end of the valve seat 8, that is, a large diameter portion is provided, and the guide hole 9 is formed coaxially with the second fitting cylinder portion 2a.

  A movable core 12 facing the front end surface of the fixed core 5 is slidably accommodated in the valve housing 2 and the annular spacer 4, and is accommodated in the movable core 12 in the guide hole 9 so as to be slidable in the axial direction. The valve body 16 is integrally coupled. The valve body 16 is in contact with the stopper plate 6 in contact with a spherical valve portion 16a that can be seated on the valve seat 8, a pair of front and rear journal portions 16b and 16b that are slidably supported in the guide hole 9. A flange 16c that defines the valve opening limit of the body 16 is integrally provided, and each of the journal portions 16b is provided with a plurality of flat surfaces 17, 17.

  The fixed core 5 has a hollow portion 21 communicating with the inside of the valve housing 2, and the movable core 12 is urged in the hollow portion 21 in the closing direction of the valve body 16, that is, in the seating direction on the valve seat 8. A coiled valve spring 22 and a pipe-shaped retainer 23 that supports the rear end of the valve spring 22 are accommodated. The retainer 23 is fixed by caulking in the hollow portion 21.

  An inlet cylinder 25 having a fuel inlet 25a communicating with the hollow portion 21 of the fixed core 5 through a pipe-like retainer 23 is integrally connected to the rear end of the fixed core 5, and a fuel filter 27 is connected to the fuel inlet 25a. Is installed.

A coil assembly 28 is fitted on the outer periphery of the annular spacer 4 and the fixed core 5. The coil assembly 28 includes a bobbin 29 fitted to the outer peripheral surfaces of the annular spacer 4 and the fixed core 5 , and a coil 30 wound around the bobbin 29, and a coil housing 31 surrounding the coil assembly 28. Is connected to the outer peripheral surface of the valve housing 2 by welding.

The coil housing 31, the coil assembly 28, and the fixed core 5 are embedded in a cover 32 made of synthetic resin, and a coupler 34 having a connection terminal 33 connected to the coil 30 is provided at an intermediate portion of the cover 32. It is connected continuously.

As clearly shown in FIG. 2, an injector plate 36 is liquid-tightly welded to the front end surface of the valve seat member 3 and a laser beam is used for the welding. The injector plate 36 includes an annular upper wall portion 37 that is joined to the valve seat member 3 by welding, and a vertical wall portion 38 that protrudes from the inner peripheral end of the upper wall portion 37 to the opposite side of the valve seat member 3. , a bottom wall 39 which defines a flat fuel passage 41 communicating with the valve hole 10 between the valve seat member 3 extending radially inwardly from the distal end of the vertical wall portion 38, the bottom wall 39 A circular raised wall 40 that rises toward the valve hole 10 from the center of the tube is integrally connected. The raised wall portion 40 has a smaller diameter than the valve hole 10 and is flush with the upper wall portion 37, and is arranged so as to form an annular gap 42 between the valve hole 10 and the opening edge to the fuel passage 41. Is done.

As shown in FIGS. 2 and 3, the fuel passage 41 includes a common diffusion chamber 41a communicating with the annular gap 42, and a plurality of branch passages 41b, 41b extending in a petal shape radially outward from the diffusion chamber 41a. A plurality of fuel injection holes 43, 43... That open these branch paths 41 b, 41 b... To the outside of the injector plate 36 are formed in the bottom wall 39.

Such an injector plate 36 is press-molded, and FIG. 4 shows the press-molding process. As shown in FIG. 4 (A), first, the injector plate 36 is placed on the die 50 and the outer periphery thereof is suppressed by the punch guide 52, and then, as shown in FIGS. 4 (B) and (C), the die plate 36 is placed. 50 and the punch 51 descending along the punch guide 52, the upper wall portion 37, the vertical wall portion 38 and the bottom wall portion 39 are simultaneously formed. At that time, in particular, the inner peripheral surface 38a of the vertical wall portion 38 is shear-formed by press forming, thereby forming a wall surface 38a so as to stand substantially vertically from the bottom wall portion 39. The outer peripheral surface 38b of the vertical wall portion 38 is compression-molded by press molding, thereby forming a tapered surface 38b having a smaller diameter toward the central portion of the injector plate 36. The absolute wall 38a and the tapered surface 38b are arranged such that the axial extension line L of the absolute wall 38a intersects the tapered surface 38b.

  Next, the operation of this embodiment will be described.

  When the coil 30 is demagnetized, the movable core 12 and the valve body 16 are pressed forward by the urging force of the valve spring 22 and are seated on the valve seat 8. Therefore, the high-pressure fuel supplied into the valve housing 2 through the fuel filter 27 and the inlet cylinder 25 is made to wait in the valve housing 2.

  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 valve housing 2, and the movable core 12, and the magnetic core is attracted to the fixed core 5 together with the valve body 16 by the magnetic force. Since the valve body 16 is separated from the valve seat 8, the high-pressure fuel in the valve housing 2 sequentially passes through the flat surfaces 17, 17... Of the valve body 16, the valve seat 8 and the valve hole 10 and fuels from the annular gap 42. It moves to the passage 41, is diffused radially in the diffusion chamber 41a of the fuel passage 41, is distributed to the plurality of branch passages 41b, 41b,..., And is injected from the fuel injection holes 43, 43. A spray foam is formed which is directed to (not shown).

  At this time, the fuel that has flowed out of the annular gap 42 into the fuel passage 41 is distributed to the plurality of fuel injection holes 43, 43... While being diffused radially in the diffusion chamber 41 a, so that the injection from the fuel injection holes 43, 43. Since atomization of fuel can be effectively promoted, a good spray foam can be obtained.

By the way, the injector plate 36 having a plurality of fuel injection holes 43, 43... Is opposite to the valve seat member 3 from the annular upper wall portion 37 welded to the valve seat member 3 and the inner peripheral end of the upper wall portion 37. a bottom wall which defines a vertical wall 38 which projects on the side, a flat fuel passage 41 communicating with the valve hole 10 between the valve seat member 3 extending radially inwardly from the distal end of the vertical wall portion 38 The fuel passage 41 can be easily formed in the injector plate 36 and the fuel passage is cut in the valve seat member 3 because it is press-molded so as to be integrated with the portion 39. Manufacturing is simplified as compared to products, and costs can be reduced.

Further, in the injector plate 36, the inner peripheral surface 38a of the vertical wall portion 38 is shear-formed by press forming so that the wall surface 38a rises substantially vertically from the bottom wall portion 39. By selecting the shape and height, the shape and volume of the fuel passage 41 can be freely set.

In particular, the upper end portion 38aa and the lower end portion 38ab of the wall surface 38a are prone to sag and cracks due to shear molding, and the wall surface 38a and the taper surface 38b of the vertical wall portion 38 are connected to the axial extension line L of the wall surface 38a. Is arranged so as to intersect with the tapered surface 38b , the material is filled into the upper end 38aa and the lower end 38ab of the pre-walled surface 38a by the compression molding of the tapered surface 38b at the time of press molding, so While the generation is suppressed, the wall face 38a can be formed accurately, and as a result, the dimensional accuracy of the fuel passage 41 can be increased, which can contribute to the stabilization of the fuel spray characteristics (flow rate, spray foam). .

  According to the test, when the injector plate 36 is made of JIS SUS304-2B, when the plate thickness of the plate 36 is T, the depth t of the fuel passage 41 can be freely set in the range of 0 <t <0.9T. I was able to set it.

  The vertical wall portion 38 formed in this way is greatly hardened by work, and connects the upper wall portion 37 and the bottom wall portion 39 having steps to each other so that a great rib effect is exhibited. , The rigidity of the injector plate 36 is effectively strengthened, and its thickness can be reduced. Therefore, since the injector plate 36 can be laser-welded to the front end surface of the valve seat member 3 with relatively little heat input, the productivity is improved and the valve seat member 3 is prevented from thermal distortion to ensure the valve closing performance. can do.

  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, the number and arrangement of the branch passages 41b and the fuel injection holes 43 can be freely selected according to the required number and shape of the fuel spray foam.

1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine 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 3-3 in FIG. 2. Explanatory drawing of the press molding process of the injector plate of the said fuel injection valve.

Explanation of symbols

I ··· Fuel injection valve L ··· Extended wall 3 · · · Valve seat member 8 · · · Valve seat 10 · · · Valve hole 16 ... valve body 36 ... injector plate 37 ... upper wall 38 ... vertical wall 38a ... ... wall face 38aa ... upper end 38ab of the wall face ... Bottom wall lower end 39 ... Bottom wall 41 ... Fuel passage 43 ... Fuel injection hole

Claims (2)

A valve seat member (3) having a valve seat (8) and a valve hole (10) penetrating through the central portion thereof, and a valve body for opening and closing the valve hole (10) in cooperation with the valve seat (8) ( 16) and an injector plate (36) which has a plurality of fuel injection holes (43) and is welded to the outer end surface of the valve seat member (3), and the injector plate (36) is connected to the valve seat. An annular upper wall portion (37) joined to the member (3), and a vertical wall portion (38) projecting from the inner peripheral end of the upper wall portion (37) to the opposite side of the valve seat member (3); , A bottom which defines a flat fuel passage (41) extending radially inward from the tip of the vertical wall portion (38) and communicating with the valve hole (10) between the valve seat member (3) and the valve seat member (3). A plurality of fuel injection holes (43) are formed in the bottom wall (39) to communicate with the inside and outside of the wall (39). In the fuel injection valve,
The inner peripheral surface of the vertical wall portion (38), with Do to said bottom wall (39) cliff face which is shearform by being sheared by substantially press-molding so as to stand vertically from (38a), said longitudinal walls and the outer peripheral surface (38), the so formed as toward the center portion diameter and a ruthenate over tapered surface of the injector plate (36) (38b), by compression molding by press molding, The fuel injection valve, wherein the vertical wall portion (38) and the bottom wall portion (39) are formed simultaneously . The fuel injection valve according to claim 1, wherein
The vertical wall portion (38) has a wall surface (38a) and a tapered surface (38b) arranged such that an axial extension line (L) of the wall surface (38a) intersects the taper surface (38b). A fuel injection valve characterized by.

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