JP3978638B2 - Manufacturing method of electromagnetic fuel injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a fuel injection valve used in an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”), and more particularly to a method for manufacturing an electromagnetic fuel injection valve driven by an electromagnetic drive device.
[0002]
[Prior art]
Conventionally, an electromagnetic fuel injection valve that reciprocally drives a valve member by applying a pulse current to an electromagnetic driving device is known. The fuel injection valve is configured such that the contact portion provided on the valve member is seated on the valve seat portion of the valve body, or the contact portion is separated from the valve seat portion, so that the fuel from the nozzle hole provided on the downstream side. Is intermittently injected.
[0003]
In a fuel injection valve used for a gasoline engine or the like, for example, when fuel flows into the combustion chamber at a time other than a predetermined time due to fuel leakage when the valve is closed, the fuel is not completely burned, and hydrocarbons (HC) in the exhaust gas Will increase. Therefore, it is necessary for the fuel injection valve to seal the valve seat part and the contact part with high accuracy when the valve is closed, that is, to improve the valve density.
[0004]
[Problems to be solved by the invention]
According to the method for manufacturing a fuel injection valve disclosed in Japanese Patent Application Laid-Open No. 9-68134, the valve body and the abutting tool and a tool with a shaft on which a spherical member having the same shape is attached are rubbed together. The shape of the spherical member is transferred to the valve seat. Thereby, the shape of the valve seat part and the shape of the contact part are made to conform and the valve density is improved.
[0005]
However, in the manufacturing method disclosed in Japanese Patent Laid-Open No. 9-68134, a tool with a shaft, which is a member different from the valve member, and the valve body are rubbed together. For this reason, there is a possibility that the coaxiality between the valve body and the valve member cannot be ensured due to a tolerance when the valve body and the valve member are assembled. As a result, the valve density between the valve seat portion of the valve body and the contact portion of the valve member is not ensured, and fuel may leak.
[0006]
In order to improve the valve density, it is conceivable to further improve the processing accuracy of the valve seat part and the contact part. However, there is a problem that the manufacturing cost increases because it takes a long time to process the valve seat portion and the contact portion in order to improve the processing accuracy more than before.
In addition, in order to meet further regulations on exhaust gas in the future, it is desired to improve the valve density more than before.
[0007]
Therefore, an object of the present invention is to provide a method for manufacturing an electromagnetic fuel injection valve that can improve the valve density at low cost.
[0008]
[Means for Solving the Problems]
According to the method for manufacturing an electromagnetic fuel injection valve according to claim 1 of the present invention, the protruding portion is formed in one or both of the vicinity of the valve seat portion of the valve body and the vicinity of the contact portion of the valve member. For example, when a protrusion is formed on the valve member, after the protrusion is formed on the valve member, an electromagnetic fuel injection valve including the valve member, the valve body, and the electromagnetic drive device is assembled. Then, the valve member is driven such that the contact portion repeats the seating and the seating with respect to the valve seat. When the contact portion repeats seating and separation from the valve seat, the projecting portion formed on the valve member is deformed, and the shape of the projecting portion can be adapted to the shape of the valve seat portion. Therefore, the valve density of the electromagnetic fuel injection valve is improved, and fuel leakage when the electromagnetic fuel injection valve is closed can be prevented.
[0009]
Moreover, the deformation | transformation part can absorb the assembly | attachment error at the time of the assembly | attachment of an electromagnetic fuel injection valve by deform | transforming. Furthermore, after assembling the electromagnetic fuel injection valve, the projecting portion can be deformed simply by driving the valve member. Therefore, since it is not necessary to improve the processing accuracy of each member of the electromagnetic fuel injection valve, it is possible to improve the valve density without increasing the manufacturing cost.
[0010]
According to the method for manufacturing an electromagnetic fuel injection valve according to claim 2 of the present invention, since the projecting portion is formed by plating, the projecting portion can be easily formed.
According to the method for manufacturing an electromagnetic fuel injection valve according to claim 3 of the present invention, since the protruding portion is formed by polishing, for example, the protruding portion is formed simultaneously with forming the valve body or the valve member into a predetermined shape. Can do.
[0011]
According to the method for manufacturing an electromagnetic fuel injection valve according to claim 4 of the present invention, the coating is formed on one or both of the inner peripheral surface of the valve body and the outer peripheral surface of the valve member. For example, when a coating is formed on the outer peripheral surface of the valve member, an electromagnetic fuel injection valve including the valve member, the valve body, and the electromagnetic drive device is assembled after the coating is formed on the outer peripheral surface of the valve member. Then, the valve member is driven such that the contact portion repeats the seating and the seating with respect to the valve seat. When the contact portion repeats seating and separation from the valve seat, the coating formed on the outer peripheral surface of the valve member is deformed, and the shape of the coating can be adapted to the shape of the valve seat. Therefore, the valve density of the electromagnetic fuel injection valve is improved, and fuel leakage when the electromagnetic fuel injection valve is closed can be prevented.
[0012]
Moreover, the assembly error at the time of the assembly of the electromagnetic fuel injection valve can be absorbed by the deformation of the coating. Further, after the electromagnetic fuel injection valve is assembled, the coating can be deformed only by driving the valve member. Therefore, since it is not necessary to improve the processing accuracy of each member of the electromagnetic fuel injection valve, it is possible to improve the valve density without increasing the manufacturing cost.
[0013]
According to the method for manufacturing an electromagnetic fuel injection valve according to claim 5 or 6 of the present invention, since the coating is formed of plating or resin, it is easy to form the coating.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A plurality of examples showing embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
An example in which the electromagnetic fuel injection valve according to the first embodiment of the present invention is applied to a fuel injection valve of a gasoline engine is shown in FIG.
[0015]
A casing 10 of an electromagnetic fuel injection valve (hereinafter simply referred to as “fuel injection valve”) 1 is a molded resin that covers the magnetic pipe 11, the fixed iron core 12, the electromagnetic drive device 40, and the like. The nozzle body 20 is coupled to the magnetic pipe 11 by laser welding or the like.
A valve needle 30 as a valve member is accommodated in the magnetic pipe 11 and the nozzle body 20 so as to be reciprocally movable. A contact portion 31 of the valve needle 30 can be seated on a valve seat portion 21 formed in the nozzle body 20. is there. The magnetic pipe 11 and the nozzle body 20 constitute a valve body.
[0016]
A joint portion 32 provided on the side opposite to the contact portion 31 of the valve needle 30 is coupled to the movable iron core 15. The fixed iron core 12 and the nonmagnetic pipe 16, and the nonmagnetic pipe 16 and the magnetic pipe 11 are coupled by laser welding or the like.
A nozzle hole member 22 formed in a thin disc shape is disposed on the end surface of the nozzle body 20 on the fuel injection side. A nozzle hole 22 a is formed in the nozzle hole member 22. When the contact portion 31 of the valve needle 30 is separated from the valve seat portion 21 of the nozzle body 20, the fuel passes through the gap between the contact portion 31 and the valve seat portion 21, and the fuel is injected from the injection hole 22a. The As shown in FIG. 1, a protrusion 33 is formed in the vicinity of the contact portion 31 of the valve needle 30.
[0017]
As shown in FIG. 2, the fixed iron core 12 has a substantially cylindrical shape, and the fuel can flow therethrough. A filter member 17 for removing fine impurities contained in the fuel is disposed at the end of the fixed iron core 12 on the side opposite to the injection hole. Further, an adjusting pipe 18 is accommodated in the fixed iron core 12. A spring 19 that urges the valve needle 30 toward the valve seat 21 is disposed at the nozzle hole side end of the adjusting pipe 18.
[0018]
An electromagnetic drive device 40 is disposed on the side of the valve needle 30 opposite to the injection hole. The electromagnetic drive device 40 includes a coil 41, a spool 42 around which the coil 41 is wound, a metal plate 43 disposed so as to cover the periphery of the spool 42, the magnetic pipe 11, the fixed iron core 12, The movable iron core 15 and the metal plate 43 constitute a magnetic circuit. By energizing the coil 41, a magnetic force is generated in the magnetic circuit, and the valve needle 30 is attracted upward together with the movable iron core 15 in FIG.
[0019]
The coil 41 is located in the casing 10 so as to cover the periphery of the fixed iron core 12 and the magnetic pipe 11 positioned so as to sandwich the nonmagnetic pipe 16 and the nonmagnetic pipe 16. The coil 41 is electrically connected to the terminal 44, and a current applied to the terminal 44 is applied to the coil 41.
[0020]
When energization of the coil 41 of the electromagnetic drive device is turned on, an electromagnetic attractive force that attracts the movable iron core 15 toward the fixed iron core 12 is generated in the coil 41. When the movable iron core 15 is attracted to the fixed iron core 12 side by this electromagnetic attraction force, the valve needle 30 is moved to the fixed iron core 12 side together with the movable iron core 15, and the contact portion 31 of the valve needle 30 is the valve seat of the nozzle body 20. Separate from the part 21. When the contact portion 31 is separated from the valve seat portion 21, a gap is generated between the contact portion 31 and the valve seat portion 21, and fuel is injected from the injection hole 22a via this gap.
[0021]
When the coil 41 is turned off and the electromagnetic attractive force disappears, the movable iron core 15 and the valve needle 30 are moved toward the valve seat portion 21 by the biasing force of the spring 19, and the contact portion 31 is seated on the valve seat portion 21. . As a result, the gap between the contact portion 31 and the valve seat portion 21 is closed, and fuel injection from the nozzle hole 22a is blocked.
[0022]
Next, the protrusion 33 will be described in detail.
As shown in FIG. 1, the protrusion 33 has a substantially quadrangular cross section, and is formed to circulate around the outer periphery of the valve needle 30 in a band shape. The protrusion 33 is formed so as not to hinder the flow of fuel, the width w of the protrusion 33 with respect to the axial direction of the valve needle 30 is w ≦ 0.1 mm, and the thickness t is 2 μm ≦ t ≦ 20 μm.
[0023]
The protruding portion 33 is made of a material that is softer than the material constituting the valve needle 30 and the nozzle body 20 and has a hardness that does not easily wear due to the collision between the contact portion 31 and the valve seat portion 21. For example, when stainless steel is used as the material of the valve needle 30 and the nozzle body 20, nickel alloy plating that is softer than stainless steel or chromium plating that has higher wear resistance than nickel alloy plating is used as the material of the protrusion 33. It is possible.
[0024]
Further, instead of forming the protruding portion 33 by plating, it is possible to form the protruding portion 33 simultaneously with the molding of the valve needle 30 at the time of polishing or cutting when the valve needle 30 is molded. When the protrusion 33 is formed by polishing or the like, the valve needle 30 and the protrusion 33 are made of the same material.
[0025]
Next, a method for manufacturing the fuel injection valve 1 will be described.
(1) Each member of the fuel injection valve 1 such as the valve needle 30 and the nozzle body 20 is formed into a predetermined shape. At this time, the contact portion 31 is formed on the valve needle 30 and the valve seat portion 21 is formed on the nozzle body 20 by, for example, polishing.
[0026]
{Circle around (2)} As shown in FIG. 1, a protruding portion 33 protruding outward in the circumferential direction of the valve needle 30 is formed on the outer peripheral portion in the vicinity of the contact portion 31 of the valve needle 30. The protrusion 33 is formed by plating at a corresponding position, or is formed by polishing or the like simultaneously with the molding of the valve needle 30.
[0027]
{Circle around (3)} Each member of the fuel injection valve 1 such as the valve needle 30, the nozzle body 20, and the electromagnetic drive device 40 is assembled into a temporary product of the fuel injection valve 1.
(4) After assembling the fuel injection valve 1, the coil 41 of the electromagnetic drive device 40 is energized to operate the valve needle 30. When the valve needle 30 is operated, the contact portion 31 of the valve needle 30 is seated on the valve seat portion 21 of the nozzle body 20, and the contact portion 31 is repeatedly separated from the valve seat portion 21. When the contact portion 31 is seated on the valve seat portion 21, the protrusion portion 33 is deformed by the contact portion 31 being struck against the valve seat portion 21, and the protrusion portion 33 is formed on the valve seat portion 21 as shown in FIG. 3. Deform to a shape along the shape. The number of times of operation, that is, the number of times that the contact portion 31 is seated on the valve seat portion 21 varies depending on the material of the protruding portion 33. For example, when nickel alloy plating or chrome plating is used as the projecting portion 33 as described above, the number of operations is tens of thousands to hundreds of thousands. At this time, assuming that the frequency of the pulse current flowing through the coil 41 is 200 Hz and the operation time is 2 milliseconds, the operation time is several tens of seconds to several hundreds of seconds.
[0028]
Further, when the protruding portion 33 is formed by polishing or the like, the protruding portion 33 is formed of the same material as that of the valve needle 30, so that the hardness of the protruding portion 33 is higher than that when formed by plating. Therefore, since the time required for the protrusion 33 to deform becomes longer, the operation time of the valve needle 30 becomes longer than when the protrusion 33 is formed by plating.
[0029]
In the first embodiment, after assembling the fuel injection valve 1 in the product state, the valve needle 30 is operated, whereby the protrusion 33 formed in the vicinity of the contact portion 31 of the valve needle 30 and the valve of the nozzle body 20. The seat 21 repeats the collision. Thereby, the protrusion part 33 deform | transforms and can adapt the shape of the protrusion part 33 to the shape of the valve seat part 21. FIG. Therefore, since the valve density between the contact portion 31 and the valve seat portion 21 is improved, it is possible to prevent fuel leakage from the gap between the contact portion 31 and the valve seat portion 21 when the valve is closed. it can.
Moreover, since the contact part 31 and the valve seat part 21 can be made to adapt by deform | transforming the protrusion part 33, the tolerance by the assembly | attachment of the fuel injection valve 1 can be absorbed, and valve density can be improved. it can.
[0030]
In the first embodiment, the protrusion 33 is deformed simply by operating the valve needle 30 after the fuel injection valve 1 is assembled, and the valve density between the contact portion 31 and the valve seat portion 21 is improved. Therefore, for example, since it is not necessary to improve the processing accuracy of the valve needle 30 or the valve body 20 more than before, the processing is easy and the manufacturing cost can be reduced.
[0031]
(Second embodiment)
FIG. 4 shows a fuel injection valve according to the second embodiment of the present invention. Components that are substantially the same as those of the first embodiment are denoted by the same reference numerals.
As shown in FIG. 4, in the fuel injection valve 1 of the second embodiment, the protruding portion 23 is formed in the vicinity of the valve seat portion 21 of the nozzle body 20. The protruding portion 23 protrudes toward the inner peripheral portion of the valve body 20 and is formed so as to go around the inner peripheral portion of the valve body 20. The width and thickness of the protruding portion 23 with respect to the axial direction of the fuel injection valve 1 are the same as the protruding portion of the first embodiment. When the contact portion 31 of the valve needle 30 is seated on the valve seat portion 21, the protruding portion 23 is hit by the contact portion 31. When the protrusion 23 is struck by the contact portion 31, the protrusion 23 is deformed into a shape along the contact portion 31.
[0032]
Therefore, the shape of the contact portion 31 and the shape of the valve seat portion 21 can be adjusted, and the valve density can be improved as in the first embodiment.
As described above, in the first embodiment and the second embodiment, the protrusion is formed in the vicinity of the contact portion 31 of the valve needle 30 or the vicinity of the valve seat portion 21 of the nozzle body 20. You may form in both the seat part 21 vicinity.
[0033]
(Third embodiment)
A fuel injection valve according to a third embodiment of the present invention is shown in FIG. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals.
As shown in FIG. 5, the fuel injection valve 1 of the third embodiment has a coating 34 formed on the outer peripheral surface of the valve needle 30. The coating 34 is formed so as not to hinder the flow of fuel in the same manner as the protrusions of the first and second embodiments, and the thickness t of the coating 34 is 2 μm ≦ t ≦ 20 μm.
[0034]
As the material of the coating 34, nickel alloy or chromium can be used in the same manner as the protruding portions of the first and second embodiments, and the coating 34 can be formed by plating them. is there. Further, it is possible to form the coating 34 with a resin such as a thermosetting resin instead of a metal material.
[0035]
After the coating 34 is formed on the outer peripheral surface of the valve needle 30, the fuel injection valve 1 is assembled and the valve needle 30 is operated. By operating the valve needle 30, the contact portion 31 of the valve needle 30 and the valve seat portion 21 of the nozzle body 20 collide, and the coating 34 on the outer peripheral surface of the valve needle 30 is deformed. Thereby, the shape of the contact portion 31 can be adapted to the shape of the valve seat portion 21, and the valve density can be improved.
[0036]
In the third embodiment, a coating 34 is formed on the outer peripheral surface of the valve needle 30. Thereby, compared with the case where a protrusion part is formed like 1st Example and 2nd Example, a processing precision can be made low and manufacturing cost can be reduced more.
In the third embodiment, the coating 34 is formed only on the outer peripheral surface of the valve needle 30, but the coating is formed only on the inner peripheral surface of the nozzle body 20, or the outer peripheral surface of the valve needle 30 and the inner peripheral surface of the nozzle body 20 are formed. A film can also be formed on both.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an electromagnetic fuel injection valve according to a first embodiment of the present invention, and is an enlarged view of a circle I in FIG.
FIG. 2 is a sectional view showing an electromagnetic fuel injection valve according to a first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a fuel injection valve according to a first embodiment of the present invention, and is an enlarged view of the same portion as FIG. 1;
4 is a cross-sectional view showing a fuel injection valve according to a second embodiment of the present invention, and is an enlarged view of the same portion as FIG. 1. FIG.
FIG. 5 is a cross-sectional view showing a fuel injection valve according to a third embodiment of the present invention, and is an enlarged view of the same portion as FIG.
[Explanation of symbols]
1 Electromagnetic fuel injection valve 11 Magnetic pipe (valve body)
20 Nozzle body (valve body)
21 Valve seat part 22a Injection hole 23 Projection part 30 Valve needle 31 Contact part 33 Projection part 34 Coating 40 Electromagnetic drive device

Claims (6)

A valve body having a valve seat portion upstream of the nozzle hole, a valve member having a contact portion that can be seated on the valve seat portion, and an electromagnetic drive device that drives the valve member, and energizing the electromagnetic drive device A method for manufacturing an electromagnetic fuel injection valve in which the contact portion is seated on or separated from the valve seat portion by intermittently interrupting, and fuel injection from the nozzle hole is intermittently performed,
Forming each of the valve body and the valve member into a predetermined shape, forming the valve seat portion on the valve body, and the contact portion on the valve member;
A protrusion made of a material softer than the material constituting the valve body and the valve member is formed in one or both of the valve body in the vicinity of the valve seat portion or in the vicinity of the contact portion of the valve member. And a process of
A step of assembling the valve body, the valve member, and the electromagnetic driving device after forming the protruding portion;
After the assembly, the energization to the electromagnetic drive device is interrupted so that the contact portion repeats the seating on the valve seat portion and the separation from the valve seat portion, and the shape of the protruding portion is changed to the valve seat portion or the contact portion. a step of Ru is deformed so as to adapt to the shape of the contact portion,
The manufacturing method of the electromagnetic fuel injection valve characterized by including these. 2. The method of manufacturing an electromagnetic fuel injection valve according to claim 1, wherein the protrusion is formed by metal plating. The method of manufacturing an electromagnetic fuel injection valve according to claim 1, wherein the protrusion is formed by polishing. A valve body having a valve seat portion upstream of the nozzle hole, a valve member having a contact portion that can be seated on the valve seat portion, and an electromagnetic drive device that drives the valve member, and energizing the electromagnetic drive device A method for manufacturing an electromagnetic fuel injection valve in which the contact portion is seated on or separated from the valve seat portion by intermittently interrupting, and fuel injection from the nozzle hole is intermittently performed,
Forming each of the valve body and the valve member into a predetermined shape, forming the valve seat portion on the valve body, and the contact portion on the valve member;
Forming a coating made of a material softer than a material constituting the valve body and the valve member on one or both of the inner peripheral surface of the valve body and the outer peripheral surface of the valve member ;
After forming the coating, assembling the valve body, the valve member, and the electromagnetic driving device;
After the assembly, the energization to the electromagnetic drive device is interrupted so that the contact portion repeats seating on the valve seat portion and separation from the valve seat portion, and the shape of the coating is changed to the valve seat portion or the contact portion. a step of thereby Ru deformed to adapt to the shape of the parts,
The manufacturing method of the electromagnetic fuel injection valve characterized by including these. 5. The method for manufacturing an electromagnetic fuel injection valve according to claim 4, wherein the coating is formed by metal plating. 5. The method for manufacturing an electromagnetic fuel injection valve according to claim 4, wherein the coating is made of resin.

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