JP2004293367A - Electromagnetic fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive electromagnetic fuel injection valve capable of providing high abrasion resistance without forming a special hard layer on slide faces of a movable core and a magnetic cylinder element. <P>SOLUTION: This electromagnetic fuel injection valve comprises a valve housing 2 sequentially coupling a valve seat member 3, a magnetic cylinder element 4 and a non-magnetic cylinder element 6; a stationary core 5 communicated with the magnetic cylinder element 4; a valve element 18 accommodated in the valve seat member 3; and a movable core 12 connected with the valve element 18 and accommodated in the magnetic cylinder element 4 and the non-magnetic cylinder element 6. The movable core 12 is slidably journaled by the magnetic cylinder element 4, and a vertical hole 19 is formed to the movable core 12 as a fuel passage. The magnetic cylinder element 4 and the movable core 12 are made of a ferrite base high hardness magnetic material, and a plurality of horizontal holes 20b opened to slide faces of the magnetic cylinder element 4 and the movable core 12 are provided to the movable core 12 perpendicular to the vertical hole 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic fuel injection valve mainly used for a fuel supply system of an internal combustion engine, and more particularly to a valve housing formed by sequentially connecting a valve seat member, a magnetic cylinder and a non-magnetic cylinder, and the magnetic cylinder. And a valve body housed in the valve seat member, the valve body being opened / closed, and connected to the valve body and provided in the magnetic cylinder and the non-magnetic cylinder so as to face the fixed core. A movable core to be accommodated, a valve spring for urging the valve body in a valve closing direction, and a valve spring are arranged so as to surround the fixed core, and the movable core is attracted to the fixed core by excitation to open the valve body. The present invention relates to an improvement in an electromagnetic fuel injection valve having a movable core slidably supported by the magnetic cylinder and a vertical hole formed as a fuel passage in the movable core.
[0002]
[Prior art]
Such an electromagnetic fuel injection valve is already known, for example, as disclosed in Patent Document 1.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-81356
[Problems to be solved by the invention]
By the way, it is effective to make the movable core slidably supported by the magnetic cylinder to stabilize the posture of the valve body. However, in general, the magnetic material constituting the movable core and the magnetic cylinder has low hardness, and When the coil is excited, side thrusts are generated on the sliding surfaces of the movable core and the magnetic cylinder when the coil is excited, so that there is a problem in wear resistance.
[0005]
Therefore, in the structure disclosed in Patent Document 1, a hardened layer is formed on the sliding surfaces of the movable core and the magnetic cylinder by shot peening or chrome plating to ensure their wear resistance.
[0006]
However, the formation of a hardened layer on the sliding surface as described above causes an increase in the number of manufacturing steps, and also requires precision control of the hardened layer. It is difficult to reduce.
[0007]
The present invention has been made in view of the above circumstances, and is an inexpensive method capable of imparting high wear resistance to a movable core and a sliding surface of a magnetic cylinder without forming a special hardened layer on the sliding surface. It is an object of the present invention to provide a simple electromagnetic fuel injection valve.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a valve housing in which a valve seat member, a magnetic cylinder and a non-magnetic cylinder are sequentially connected, a fixed core connected to the magnetic cylinder, and the valve seat. A valve body that is housed in a member and that opens and closes, a movable core that is connected to the valve body and that is housed in the magnetic cylinder and the non-magnetic cylinder so as to be opposed to the fixed core, and that closes the valve body. A valve spring for biasing in the valve direction, and a coil arranged to surround the fixed core and to attract the movable core to the fixed core by excitation to open the valve body. The magnetic cylinder and the movable core are made of a ferrite-based high-hardness magnetic material in an electromagnetic fuel injection valve in which the magnetic cylinder is slidably supported on the magnetic cylinder and a vertical hole is formed in the movable core as a fuel passage. At the same time, the magnetic cylinder is inserted into the movable core at right angles to the And the first feature in that a plurality of lateral holes opening to the sliding surface of the movable core.
[0009]
According to the first feature, the fuel that has flowed into the vertical holes can be supplied to the sliding surfaces of the movable core and the magnetic cylinder through the plurality of second horizontal holes to lubricate and cool them. In addition, the movable core and the magnetic cylinder are made of a ferrite-based high hardness magnetic material. Accordingly, both the wear resistance of the movable core and the magnetic cylinder and the response of the valve body can be improved.
[0010]
Moreover, since it is not necessary to perform a special abrasion treatment on the movable core and the magnetic cylinder made of a ferrite-based high-hardness magnetic material, the number of manufacturing steps can be reduced, and the cost can be reduced.
[0011]
Further, the lateral hole crossing the movable core can suppress generation of an eddy current in the movable core during excitation and demagnetization of the coil, and can prevent heating of the movable core due to the eddy current.
[0012]
Further, in addition to the role of the fuel passage, the vertical hole and the horizontal hole also serve to eliminate the thickness of the movable core, thereby contributing to the reduction of the weight of the movable core and the improvement of the responsiveness of the valve body.
[0013]
According to the present invention, in addition to the first feature, an annular guide convex portion is slidably fitted to one of an outer peripheral surface and an inner peripheral surface of the movable core and the magnetic cylinder opposed to each other. The second feature is that a gap is provided between the outer peripheral surface and the inner peripheral surface, and the lateral hole is opened in the sliding surface of the guide projection.
[0014]
According to the second feature, the fuel that has passed through the lateral hole is supplied to the sliding surface of the guide convex portion and the gap between the movable core and the magnetic cylinder before and after the guide convex portion, and the sliding of the guide convex portion is performed. The movable core and the magnetic cylinder can be effectively cooled as well as the surface lubrication, and the wear resistance of the movable core and the magnetic cylinder and the response of the valve can be further improved.
[0015]
Further, in the present invention, in addition to the second feature, a third feature is that the diameter of the lateral hole is set to be larger than the axial width of the guide projection.
[0016]
According to the third feature, the fuel that has passed through the lateral hole can be simultaneously supplied to the sliding surface of the guide projection and the gap between the movable core and the magnetic cylinder before and after the guide projection. Lubrication of the sliding surface and cooling of the movable core and the magnetic cylinder can be performed more effectively.
[0017]
Still further, according to the present invention, in addition to the first feature, the high-hardness magnetic material comprises 10 to 20% by weight of Cr, 0.1% by weight of Si, 1% by weight or more of at least one of Al and Ni, and a balance of ferrite. A fourth feature is that the alloy contains Fe, Mn, C, P, and S, and the total of Al and Ni is 1.15 to 6 wt%.
[0018]
According to the fourth feature, it is possible to obtain a movable core and a magnetic cylinder having excellent magnetic properties, high hardness of 200 to 400 Hmv, and excellent wear resistance by merely processing the alloy.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.
[0020]
1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is an enlarged view of a part of FIG. 1, and FIG. 3 shows a second embodiment of the present invention. FIG. 4 is a diagram showing the relationship between the total content of Al and Ni and the hardness in the movable core and the alloy for the magnetic cylinder, and FIG. 5 is a diagram showing the total content of Al and Ni in the alloy. It is a diagram which shows the relationship between magnetic flux density and volume resistance.
[0021]
First, a description will be given of the first embodiment of the present invention shown in FIGS.
[0022]
In FIG. 1, a valve housing 2 of an electromagnetic fuel injection valve I for an internal combustion engine has a cylindrical valve seat member 3 having a valve seat 8 at a front end, and is coaxially connected to a rear end of the valve seat member 3. It comprises a magnetic cylinder 4 and a non-magnetic cylinder 6 coaxially coupled to the rear end of the magnetic cylinder 4.
[0023]
The valve seat member 3 has, at its rear end, a connecting cylinder 3a protruding toward the magnetic cylinder 4 with an annular shoulder 3b from the outer peripheral surface thereof, and an annular coupling to the outer peripheral surface of the coupling cylinder 3a. A groove 38 is formed. The connecting cylinder 3a is fitted to the inner peripheral surface of the front end of the magnetic cylinder 4, and the front end of the magnetic cylinder 4 is brought into contact with the annular shoulder 3b. Then, the peripheral wall of the magnetic cylinder 4 is caulked. The valve seat member 3 and the magnetic cylinder 4 are coaxially and liquid-tightly connected to each other by making the connection groove 38 cut into the entire circumference.
[0024]
The magnetic cylinder 4 and the non-magnetic cylinder 6 are coaxially and liquid-tightly joined to each other by laser beam welding over the entire circumference with their facing end faces abutting.
[0025]
The valve seat member 3 has a valve hole 7 opened at the front end surface thereof, a conical valve seat 8 connected to the inner end of the valve hole 7, and a cylindrical guide hole 9 connected to a large diameter portion of the valve seat 8. And An injector plate 10 made of a steel plate having a plurality of fuel injection holes 11 communicating with the valve hole 7 is liquid-tightly welded to the front end surface of the valve seat member 3 in a liquid-tight manner.
[0026]
The fixed core 5 is press-fitted and fixed to the inner peripheral surface of the non-magnetic cylinder 6 from the rear end side in a liquid-tight manner. At this time, a portion that does not fit with the fixed core 5 is left at the front end of the non-magnetic cylinder 6, and the valve assembly V is accommodated in the valve housing 2 extending from the portion to the valve seat member 3.
[0027]
The valve assembly V is connected to a valve body 18 comprising a hemispherical valve part 16 for opening and closing the valve hole 7 in cooperation with the valve seat 8 and a valve rod part 17 for supporting the same, and a valve rod part 17. And a movable core 12 which extends from the magnetic cylinder 4 to the non-magnetic cylinder 6, is inserted therein, and is coaxially opposed to the fixed core 5. The valve rod 17 and the movable core 12 are fitted with a stopper element 14 formed coaxially and integrally with the valve rod 17 in a connection hole 36 at the center of the movable core 12, and the fitting depth is determined by the valve rod. It is regulated by bringing the flange 35 integrated with the part 17 into contact with the front end face of the movable core 12. Then, in order to firmly connect the movable core 12 and the valve body 18, a swaged portion 12 b is formed on the movable core 12 so as to cover a peripheral portion on the flange portion 35 side.
[0028]
The tip end of the stopper element 14 protrudes from the suction surface 12a of the movable core 12, and is usually opposed to the suction surface 5a of the fixed core 5 with a gap s corresponding to the valve opening stroke of the valve element 18. You. The amount g of protrusion of the stopper element 14 from the suction surface 12a of the movable core 12 is determined by the distance between the suction surfaces 5a and 12a of the fixed core 5 and the movable core 12 when the stopper element 14 contacts the fixed core 5. The air gap g is set so that when the coil 30 is demagnetized from the excited state, the residual magnetic flux between the cores 5 and 12 is quickly eliminated. The end surface of the stopper element 14 and the suction surface 12a of the movable core 12 are simultaneously finished by grinding after the stopper element 14 is fitted into the movable core 12. In this manner, the gap s and the air gap g related to each other can be precisely obtained.
[0029]
The valve rod portion 17 is formed to have a diameter sufficiently smaller than the guide hole 9, and its outer peripheral surface protrudes radially outward and is slidably supported on the inner peripheral surface of the guide hole 9. The first guide projection 25a is integrally formed in the vicinity of the valve portion 16.
[0030]
On the outer peripheral surface of the movable core 12, an annular second guide convex portion 25b slidably supported on the inner peripheral surface of the magnetic cylinder 4 is integrally formed. Thus, a gap 37 is provided between the movable core 12 and the magnetic cylinder 4 before and after the second guide projection 25b.
[0031]
The valve assembly V is provided with a vertical hole 19 starting from the end face of the stopper element 14 and reaching a dead end beyond the center O of the hemispherical valve portion 16, and the vertical hole 19 is located closer to the valve portion 16 than the first guide convex portion 25a. The first horizontal hole 20a communicating with the outer peripheral surface of the valve rod portion 17 and the vertical hole 19 are connected to the second horizontal hole 20b and the vertical hole 19 communicating with the outer peripheral surface of the second guide projection 25b. A third lateral hole 20c communicating with the outer peripheral surface of the valve rod portion 17 in the central portion between the second guide 12 and the first guide convex portion 25a is provided. At this time, the first horizontal hole 20 a is formed in the valve rod portion 17, and the number thereof is at least two orthogonal to the vertical hole 19. The second horizontal hole 20b is formed from the movable core 12 to the stopper element 14, and the number of the second horizontal hole 20b is at least two orthogonal to the vertical hole 19. The diameter d of the second lateral hole 20b is set to be larger than the axial width w of the second guide projection 25b.
[0032]
In the middle of the vertical hole 19, an annular spring seat 24 facing the fixed core 5 side is formed.
[0033]
The fixed core 5 has a vertical hole 21 communicating with the vertical hole 19 of the movable core 12, and a fuel inlet tube 26 internally communicating with the vertical hole 21 is integrally connected to the rear end of the fixed core 5. The fuel inlet tube 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. The pipe shape is inserted or lightly pressed into the vertical hole 21 from the reduced diameter portion 26a. A valve spring 22 for urging the movable core 12 toward the valve closing side of the valve body 18 is contracted between the retainer 23 and the spring seat 24. At this time, the set load of the valve spring 22 is adjusted by the fitting depth of the retainer 23 into the vertical hole 21, and after the adjustment, the outer peripheral wall of the reduced diameter portion 26 a is partially caulked inward to thereby retain the retainer 23. Is fixed to the reduced diameter portion 26a. A fuel filter 27 is mounted on the enlarged diameter portion 26b.
[0034]
The fixed core 5, the movable core 12, and the magnetic cylinder 4 are all made of a ferrite-based high-hardness magnetic material, and are specifically formed by cutting an alloy having the following composition.
[0035]
Cr: 10-20 wt%
Si ・ ・ ・ 0.1wt%
Al and Ni: both of them are contained, at least one of them is 1 wt% or more, and the total of both is 1.15 to 6 wt%
Remaining part: ferritic Fe, impurities Mn, C, P, S
The fact that the total of Al and Ni in the above alloys is 1.15 to 6% by weight, in particular, greatly improves the wear resistance, magnetic force and response of the fixed core 5, the movable core 12 and the magnetic cylinder 4. Involved. That is, about 95% of the total content of Al and Ni becomes precipitates, which greatly affects the hardness, magnetic flux density and volume resistance of the fixed core 5, the movable core 12 and the magnetic cylinder 4. The hardness is desirably large for obtaining abrasion resistance, the magnetic flux density is desirably large for enhancing magnetic force, and the volume resistance is desirably small for enhancing responsiveness.
[0036]
When the relationship between the total content of Al and Ni in the alloy and the hardness were examined by experiments, the results shown in the diagram of FIG. 4 were obtained. The relationship between the total content of Al and Ni in the alloy and the magnetic flux density and the volume resistance was examined by experiments, and the results shown in the diagram of FIG. 5 were obtained.
[0037]
As is clear from FIG. 4, as long as the total content of Al and Ni is 1.15 to 6 wt%, the hardness of the alloy is 200 to 400 Hmv. The hardness in this range is sufficient to impart sufficient wear resistance to the fixed core 5, the movable core 12, and the magnetic cylinder 4 without performing any special wear treatment such as plating after cutting the alloy. is there.
[0038]
As is apparent from FIG. 5, when the total content of Al and Ni exceeds 6 wt%, the magnetic flux densities of the fixed core 5, the movable core 12, and the magnetic cylinder 4 decrease, and a sufficient magnetic force cannot be obtained. In addition, the flow of the magnetic flux is delayed due to the decrease in the volume resistance, and the responsiveness of the fixed core 5 is reduced.
[0039]
Therefore, by setting the total content of Al and Ni to 1.15 to 6 wt%, the wear resistance, magnetic force, and responsiveness of the fixed core 5, the movable core 12, and the magnetic cylinder 4 can be practically satisfied. it can.
[0040]
Incidentally, 10 to 20 wt% of Cr, 0.1 wt% of Si, and the balance of ferrite-based Fe and impurities Mn, C, P and S in the alloy are generally contained in conventional magnetic materials.
[0041]
On the other hand, the valve element 18 integrally formed with the stopper element 14 is made of a material that is nonmagnetic or less magnetic than the movable core 12, for example, JIS SUS304 or SUS440C.
[0042]
Referring again to FIG. 1, a coil assembly 28 is fitted around the outer periphery of the valve housing 2 in correspondence with the fixed core 5 and the movable core 12. The coil assembly 28 includes a bobbin 29 fitted on the outer peripheral surface of the magnetic cylinder 4 from the rear end to the entire non-magnetic cylinder 6, and a coil 30 wound around the bobbin 29. The front end of the coil housing 31 surrounding the coil assembly 28 is welded to the outer peripheral surface of the magnetic cylinder 4, and the rear end is welded to the outer peripheral surface of the yoke 5 b projecting in a flange shape from the outer periphery of the rear end of the fixed core 5. Is done. The coil housing 31 has a cylindrical shape, and has a slit 31a formed on one side and extending in the axial direction.
[0043]
The coil housing 31, the coil assembly 28, the fixed core 5, and the first half of the fuel inlet tube 26 are embedded in a synthetic resin covering 32 formed by injection molding. At this time, the covering 32 is filled into the coil housing 31 through the slit 31a. A coupler 34 for accommodating a connection terminal 33 connected to the coil 30 is integrally connected to an intermediate portion of the cover 32.
[0044]
Next, the operation of the first embodiment will be described.
[0045]
In a state where the coil 30 is demagnetized, the valve assembly V is pressed forward by the urging force of the valve spring 22, and the hemispherical valve portion 16 of the valve body 18 is seated on the valve seat 8 in a conical shape of the valve seat member 3. Therefore, the tight seating state is obtained, and the valve hole 7 is reliably shut off. Therefore, fuel pumped from a fuel pump (not shown) to the fuel inlet cylinder 26 enters the valve housing 2 through the inside of the pipe-shaped retainer 23, the vertical hole 19 of the valve assembly V, and the first to third horizontal holes 20a to 20c. It is made to stand by and provided for lubrication and cooling around the first and second guide projections 25a and 25b.
[0046]
When the coil 30 is energized by energization, the magnetic flux generated by it runs through the fixed core 5, the coil housing 31, the magnetic cylinder 4 and the movable core 12 sequentially, and the movable core 12 of the valve assembly V sets the valve spring 22 by the magnetic force. The valve core 18 is separated from the valve seat 8 by being sucked by the fixed core 5 against the load, so that the valve hole 7 is opened, and the high-pressure fuel in the valve seat member 3 exits the valve hole 7 and the fuel is injected. The fuel is injected from the hole 11 toward the intake valve of the engine.
[0047]
At this time, the stopper element 14 fitted and fixed to the movable core 12 of the valve assembly V comes into contact with the suction surface 5a of the fixed core 5, so that the valve opening limit of the valve body 18 is defined, and the suction of the movable core 12 is performed. The surface 12a faces the suction surface 5a of the fixed core 5 with an air gap g therebetween, and direct contact with the fixed core 5 is avoided. In particular, by controlling the dimension of the amount of protrusion of the stopper element 14 from the suction surface 12a of the movable core 12, the air gap g can be obtained accurately and easily, and the stopper element 14 is non-magnetic or weakly magnetic. In addition, the residual magnetism between the cores 5 and 12 when the coil 30 is demagnetized disappears quickly, and the valve closing response of the valve element 18 can be improved.
[0048]
During opening and closing operations of the valve assembly V, the first and second guide projections 25a and 25b slide on the inner peripheral surface of the valve housing 2 so that the valve assembly V is always held in a proper posture without falling down. The fuel injection characteristics can be stabilized.
[0049]
In addition, a second horizontal hole 20b having a diameter d larger than the axial width w of the second guide projection 25b is opened on the outer peripheral surface of the second guide projection 25b formed on the movable core 12, so that the vertical side is vertical. The fuel that has flowed into the hole 19 is efficiently and simultaneously supplied to the sliding surface of the second guide protrusion 25b and the gap 37 between the movable core 12 and the magnetic cylinder 4 before and after the second through hole 20b. As a result, the movable core 12 and the magnetic cylinder 4 can be effectively cooled, as well as the sliding surface of the second guide projection 25b, and the responsiveness and wear resistance of the valve assembly V can be improved. Can be planned. Moreover, the movable core 12 and the magnetic cylinder 4 are made of a ferrite-based high hardness magnetic material as described above, and can exhibit good magnetic properties and high wear resistance by themselves. The responsiveness and wear resistance of the fuel cell can be further improved, and the fuel injection characteristics can be stabilized for a long period of time. Further, since it is not necessary to perform a special wear-resistant treatment on the movable core 12 and the magnetic cylinder 4 made of a ferrite-based high-hardness magnetic material, the number of manufacturing steps can be reduced, and the cost can be reduced.
[0050]
Further, the second horizontal hole 20b crossing the movable core 12 can suppress generation of an eddy current in the movable core 12 when exciting and demagnetizing the coil 30, and can prevent heating of the movable core 12 due to the eddy current.
[0051]
Further, the vertical hole 19 formed so as to go beyond the center of the hemispherical valve portion 16 and approach the distal end face thereof is provided together with the first to third horizontal holes 20a to 20c, in addition to the role of the fuel passage, as well as a valve assembly. It also plays a significant role in removing the extravagance of the three-dimensional V, and contributes to the reduction in the weight of the valve assembly V and, consequently, the improvement in responsiveness.
[0052]
Next, a second embodiment of the present invention shown in FIG. 3 will be described.
[0053]
In the second embodiment, an annular second guide convex portion 25b for slidably supporting the outer peripheral surface of the movable core 12 is formed on the inner peripheral surface of the magnetic cylinder 4, and other configurations are the same as those of the previous embodiment. Since the configuration is the same as that of the example, in FIG. 3, portions corresponding to those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0054]
The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention.
[0055]
【The invention's effect】
As described above, according to the first aspect of the present invention, a valve housing formed by sequentially coupling a valve seat member, a magnetic cylinder, and a non-magnetic cylinder, a fixed core connected to the magnetic cylinder, A valve body that is housed in the valve seat member and that opens and closes, a movable core connected to the valve body and housed in the magnetic cylinder and the non-magnetic cylinder so as to face the fixed core, A valve spring for urging the body in a valve closing direction, and a coil disposed to surround the fixed core and to open the valve body by attracting the movable core to the fixed core by excitation. A movable core is slidably supported by the magnetic cylinder, and a vertical hole is formed in the movable core as a fuel passage. In the electromagnetic fuel injection valve, the magnetic cylinder and the movable core are made of a ferrite-based high-hardness magnetic material. And the magnetic core is inserted into the movable core at right angles to the vertical hole. Since a plurality of horizontal holes are provided on the sliding surfaces of the cylinder and the movable core, the fuel flowing into the vertical holes is supplied to the sliding surfaces of the movable core and the magnetic cylinder through the plurality of second horizontal holes. That the movable core and the magnetic cylinder are made of ferrite-based high-hardness magnetic material. In addition, the wear resistance of the movable core and the magnetic cylinder and the response of the valve Sex can be improved. Moreover, since it is not necessary to perform a special abrasion treatment on the movable core and the magnetic cylinder made of a ferrite-based high-hardness magnetic material, the number of manufacturing steps can be reduced, and the cost can be reduced. Further, the lateral hole crossing the movable core can suppress generation of an eddy current in the movable core during excitation and demagnetization of the coil, and can prevent heating of the movable core due to the eddy current. Further, in addition to the role of the fuel passage, the vertical hole and the horizontal hole also serve to remove the extravagance of the valve assembly, and contribute to the reduction of the weight of the movable core and the improvement of the responsiveness of the valve body.
[0056]
According to the second aspect of the present invention, in addition to the first aspect, one of the outer peripheral surface and the inner peripheral surface of the movable core and the magnetic cylinder opposed to each other is slidably fitted to the other. An annular guide projection that fits is formed, a gap is provided between the outer peripheral surface and the inner peripheral surface, and the lateral hole is opened in the sliding surface of the guide convex portion. Is supplied to the sliding surface of the guide convex portion and the gap between the movable core and the magnetic cylinder before and after the guide convex portion, which not only lubricates the sliding surface of the guide convex portion but also cools the movable core and the magnetic cylinder. It is possible to further improve the wear resistance of the movable core and the magnetic cylinder, and the responsiveness of the valve body.
[0057]
According to the third aspect of the present invention, in addition to the second aspect, the diameter of the lateral hole is set to be larger than the axial width of the guide projection, so that the fuel passing through the lateral hole can be guided. It can be supplied simultaneously to the sliding surface of the convex part and the gap between the movable core and the magnetic cylinder before and after it, and more effectively lubricate the sliding surface of the guide convex part and cool the movable core and the magnetic cylinder. Can be done
[0058]
According to a fourth aspect of the present invention, in addition to the first aspect, the high-hardness magnetic material comprises 10-20 wt% of Cr, 0.1 wt% of Si, and 1 wt% of at least one of Al and Ni. % Or more, with the balance being ferrite-based Fe, Mn, C, P, and S, and the total of Al and Ni being 1.15 to 6 wt%. It is possible to obtain a movable core and a magnetic cylinder which are excellent, have a high hardness of 200 to 400 Hmv, and have excellent wear resistance.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine according to a first embodiment of the present invention; FIG. 2 is an enlarged view of a part of FIG. 1 FIG. 3 shows a second embodiment of the present invention; FIG. 4 is a cross-sectional view corresponding to FIG. 2; FIG. 4 is a diagram showing the relationship between the total content of Al and Ni and hardness in the movable core and the alloy for the magnetic cylinder. FIG. 5 is the total content of Al and Ni in the alloy. Diagram showing the relationship between magnetic flux density and volume resistance [Explanation of symbols]
I: Electromagnetic fuel injection valve V: Valve assembly d: Diameter w of horizontal hole (second horizontal hole): Guide protrusion (second guide protrusion) ) Axial width 2 ... Valve housing 3 Valve seat member 4 Magnetic cylinder 5 Fixed core 6 Non-magnetic cylinder 12, movable core 18, valve body 22, valve spring 25b, guide projection (second guide projection)
30 ... coil 37 ... gap

Claims (4)

A valve housing (2) formed by sequentially connecting a valve seat member (3), a magnetic cylinder (4) and a non-magnetic cylinder (6); and a fixed core (5) connected to the magnetic cylinder (4). ), A valve body (18) housed in the valve seat member (3) and opening and closing, and the magnetic cylinder body connected to the valve body (18) so as to face the fixed core (5). (4) a movable core (12) housed in the non-magnetic cylinder (6), a valve spring (22) for urging the valve body (18) in a valve closing direction, and the fixed core (5). And a coil (30) for energizing the movable core (12) to attract the movable core (12) to the fixed core (5) to open the valve element (18). ) Is slidably supported on the magnetic cylinder (4), and a vertical hole (19) is formed as a fuel passage in the movable core (12). In the fuel injection valve,
The magnetic cylinder (4) and the movable core (12) are made of a ferrite-based high-hardness magnetic material, and the movable core (12) is perpendicular to the vertical hole (19). ) And a plurality of lateral holes (20b) opening in the sliding surface of the movable core (12). The electromagnetic fuel injection valve according to claim 1,
An annular guide convex portion (25b) is formed on one of the outer peripheral surface and the inner peripheral surface of the movable core (12) and the magnetic cylinder (4) facing each other so as to be slidably fitted to the other. An electromagnetic fuel injection valve characterized in that a gap (37) is provided between the outer peripheral surface and the inner peripheral surface, and the lateral hole (20b) is opened in a sliding surface of the guide projection (25b). . The electromagnetic fuel injection valve according to claim 2,
An electromagnetic fuel injection valve, wherein a diameter (d) of the lateral hole (20b) is set to be larger than an axial width (w) of the guide projection (25b). The electromagnetic fuel injection valve according to claim 1,
The high-hardness magnetic material contains 10 to 20% by weight of Cr, 0.1% by weight of Si, 1% by weight or more of at least one of Al and Ni, and the balance includes ferrite-based Fe, Mn, C, P, S, and Al. An electromagnetic fuel injection valve characterized in that it is an alloy in which the total of Ni and Ni is 1.15 to 6 wt%.

Images