JP3861944B2 - Manufacturing method of fuel injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a fuel injection valve that supplies fuel from one end side opening of a cylindrical valve housing.
[0002]
[Prior art]
The distance from the fuel injection valve mounting position to the intake valve varies depending on the engine specifications. If the distance from the injection hole to the intake valve is long, the sprayed fuel spreads inside the intake pipe and the fuel spray is drawn into the intake pipe. It becomes easy to adhere to the inner wall and liquefy. When the liquefied fuel flows into the combustion chamber, the amount of hydrocarbon (HC) generated as an unburned component increases.
[0003]
[Problems to be solved by the invention]
If the fuel injection valve is brought close to the intake valve and fuel is injected in the vicinity of the intake valve, it is possible to suppress the fuel from adhering to the inner wall of the intake pipe and liquefying. However, the mounting position of the fuel injection valve is usually determined, and the fuel injection valve cannot be easily brought close to the intake valve.
[0004]
It is also conceivable to extend the injection side of the fuel injection valve to bring the injection hole closer to the intake valve without changing the mounting position of the fuel injection valve. However, the valve housing of the conventional fuel injection valve is composed of a plurality of members in the axial direction, and particularly the members on the fuel injection side such as the valve body are formed in a complicated shape. When the required length on the injection side of the valve is different, it is necessary to process the members having complicated shapes having different lengths. Therefore, there is a problem that the manufacturing cost increases because the number of parts increases and the parts cannot be standardized.
[0005]
An object of the present invention is to provide a method for manufacturing a fuel injection valve, in which a valve housing having a nonmagnetic portion between a fuel suction portion and a valve body can be easily integrally formed to an arbitrary length.
Another object of the present invention is to provide a fuel injection valve in which a connecting member for connecting a cylindrical member formed separately and a valve body is formed to an arbitrary length, and a valve housing can be easily formed to an arbitrary length. It is to provide a manufacturing method.
[0006]
[Means for Solving the Problems]
According to the method for manufacturing a fuel injection valve according to claim 1 or 2, the valve housing of the fuel injection valve is obtained by cutting the integrally formed bottomed cylindrical member into a predetermined length and making the predetermined portion non-magnetic. Is forming. Therefore, since the valve housing can be formed from the bottomed cylindrical member, which is a common member, through a process of cutting and demagnetization that can easily adjust the injection side length of the fuel injection valve, fuel having various injection side lengths can be formed. An injection valve can be easily manufactured by forming a nonmagnetic part in the site | part in a fixed distance from the opening end obtained, for example by cutting | disconnection.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples showing embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A first embodiment of the present invention is shown in FIG. The valve housing 11 is integrally formed from the injection side in the order of a valve body 12, an intermediate pipe 13 as a nonmagnetic part, and a fuel connector 14 as a fuel suction part. The valve body 12 and the fuel connector 14 are magnetized, and the intermediate pipe 13 is non-magnetic. An O-ring 50 that seals a connection portion with an intake manifold (not shown) is fitted on the outer peripheral side of the valve body 12, and a connection portion with a delivery pipe (fuel pipe) (not shown) is sealed on the upper outer peripheral side of the fuel connector 14. An O-ring 51 made of resin is fitted.
[0009]
A needle valve 20 as a valve member is accommodated inside the valve body 12, and an injection hole plate 15 is fixed to the outer bottom surface of the valve body 12 by laser welding or the like. A resin sleeve 16 covers the nozzle hole plate 15 and the valve body 12. The nozzle hole 15a formed in the nozzle hole plate 15 is opened and closed when the needle valve 20 is separated from the valve seat 12a and seated on the valve seat 12a.
[0010]
The needle valve 20 is urged toward the valve seat 12a by the urging force of the spring 26, and a contact portion 21 formed at the tip of the needle valve 20 can be seated on the valve seat 12a. The sliding portion 22 is formed on the side of the contact portion 21 opposite to the injection hole 12a, and is supported on the inner wall of the valve body 12 so as to be able to reciprocate. In order to form a fuel passage between the outer wall of the sliding portion 22 and the inner peripheral wall of the valve body 12, four chamfers are provided. A joint portion 23 that is coupled to the movable core 24 is formed on the needle valve 20.
[0011]
The movable core 24 is formed in a hollow shape and is coupled to the joint 23 of the needle valve 20 by press-fitting or the like. The movable core 24 is located at the upper part of the valve body 12 and substantially in the middle of the intermediate pipe 13, and the upper end surface of the movable core 24 faces the lower end surface of the fixed core 25. The movable core 24 is urged toward the valve seat 12 a by a spring 26 accommodated in the fixed core 25. An escape groove portion 13 a for smooth sliding of the movable core 24 is formed at a position corresponding to the gap between the movable core 24 and the fixed core 25 on the inner peripheral portion of the intermediate pipe 13.
[0012]
The fixed core 25 is press-fitted into the valve housing 11 across the magnetized fuel connector 14 and the non-magnetized intermediate pipe 13. The fixed core 25 is formed with a slit 25a. When the slit 25a is compressed during press-fitting, the fixed core 25 can be easily press-fitted, and after the press-fitting, the fixed core 25 is spring-backed. It is press-fitted and fixed in the valve housing 11.
[0013]
Nonmagnetic hard chrome plating is applied to both the lower end surface of the fixed core 25 and the upper end surface of the movable core 24, and this plating film is used as a solid gap. Further, two chamfered portions 23a are formed in the joint portion 23 of the needle valve 20, and the fuel flowing inside the fixed core 25 passes between the movable core 24 and the two chamfered portions 23a to be the valve body. 12 flows into the interior.
[0014]
The pipe-shaped adjuster 27 is attached to the inner peripheral side of the fixed core 25 by press fitting or the like. The urging force of the spring 26 can be adjusted by adjusting the press-fitting amount of the adjuster 27. The fuel filter 28 is disposed above the fixed core 25 and filters the fuel sent from the delivery pipe. The fuel that has passed through the fuel filter 28 passes through the inner periphery of the adjuster 27 and the spring 26 and flows toward the nozzle hole 12a.
[0015]
The solenoid 30 is attached to the outer periphery of the valve housing 11. The solenoid 30 is formed by assembling an electromagnetic coil 31, a resin spool 32 around which the electromagnetic coil 31 is wound, a yoke 33, and a resin connector 40 into a magnetic material housing 34. A terminal 41 for energizing the electromagnetic coil 31 is insert-molded in the connector 40. A solenoid 30 is mounted on the outer periphery of the valve housing 11 so that the electromagnetic coil 31 is positioned on the outer peripheral portion of the intermediate pipe 13, and the yoke 33 is sandwiched between the fuel connector 14 and the housing 34. Is fixed to the valve body 12 by spot welding.
[0016]
In the fuel injection valve 10 configured as described above, when the energization to the electromagnetic coil 31 is turned off, the movable core 24 is moved downward in FIG. The portion 21 is seated on the valve seat 12a, and the nozzle hole 15a is closed.
When energization of the electromagnetic coil 31 is turned on, a magnetic flux is generated around the electromagnetic coil 31, and the generated magnetic flux flows through a magnetic circuit surrounding the electromagnetic coil 31. This magnetic circuit includes a path of the housing 34, the yoke 33, the fuel connector 14, the fixed core 25, the movable core 24, the valve body 12, and the housing 34. The intermediate pipe 13, which is a nonmagnetic part, plays a role of preventing the magnetic flux from being short-circuited between the fuel connector 14 and the valve body 12. When magnetic flux flows through this magnetic circuit, a magnetic attractive force is generated between the fixed core 25 and the movable core 24, the movable core 24 is attracted toward the fixed core 25, and the needle valve 20 is separated from the valve seat 12a. Thereby, the fuel in the valve body 12 is injected from the injection hole 15a through the through hole 16a of the sleeve 16.
[0017]
Next, the manufacturing process of the valve housing 11 will be described.
As the disk-shaped substrate 100 shown in FIG. 2A, austenitic stainless steel or the like is used. The substrate 100 is not magnetized in the state before processing shown in FIG. The base material 100 is processed in the order of (B), (C), and (D) of FIG. Further, the cylindrical member 101 is processed in the order of FIGS. 2E and 2F by ironing from the bottom of the cylindrical member 101 to form the cylindrical member 102 as a bottomed cylindrical member that is thinner than the cylindrical member 101 and has a long axial length. In this way, the cylindrical member 102 is magnetized through drawing and ironing.
[0018]
Next, the cylindrical member 102 is cut to the required length to form the cylindrical member 103 shown in FIG. 3A, and is separated from the opening end 103a of the cylindrical member 103 by a predetermined distance by electromagnetic induction heating by the coil 104. Demagnetize the site. The cylindrical member 105 shown in FIG. 3B formed in this way is configured in the order of the magnetic part 110, the nonmagnetic part 111, and the magnetic part 112 from the bottom side. The magnetic parts 110 and 112 constitute the valve body 12 and the fuel connector 14 of the valve housing 11, respectively, and the nonmagnetic part 111 constitutes the intermediate pipe 13 of the valve housing 11. The valve housing 11 is formed by processing the details of the cylindrical member 105 provided with the nonmagnetic portion 111.
[0019]
According to the first embodiment of the present invention described above, after the cylindrical member 102 is integrally formed, the cylindrical member 102 is cut into a predetermined length to form the cylindrical member 103, and then subjected to post-processing such as electromagnetic induction heating. The intermediate pipe 13 that is a non-magnetic portion can be formed at a position separated from the opening end 103a of the cylindrical member 103 by a predetermined distance. When the fuel injection valve is brought close to the intake valve, it is only necessary to change the lengths of the needle valve 20 and the valve body 12 as constituent members of the fuel injection valve excluding the sleeve 16, and the distance from the opening end 103a to the nonmagnetic portion. Is constant regardless of the length of the fuel injection valve. Therefore, when forming the intermediate pipe 13 in fuel injection valves of various lengths, it is convenient in manufacturing that the nonmagnetic part can always be formed at a constant distance from the opening end 103a.
[0020]
Therefore, it is possible to easily form a valve housing having various lengths by extending the length of the fuel injection side, that is, the valve body. It is necessary to change the lengths of the valve member and the sleeve in accordance with the length of the valve housing. Since the fuel injection valve 10 manufactured in this way can inject fuel at a position closer to the intake valve even at the same mounting position as the conventional one, the atomized spray injected from the fuel injection valve 10 It is possible to suppress the fuel from adhering to the inner wall of the intake pipe and liquefying, and to reduce the amount of HC generated as an unburned component.
[0021]
In the first embodiment, the cylindrical member 102 is integrally molded using austenitic stainless steel that has not been magnetized before molding. However, the cylindrical member 102 is integrally molded with a material that is magnetized before molding. After cutting into a predetermined length, the valve housing 11 may be formed by demagnetizing a predetermined portion. Alternatively, the cylindrical member 102 may be cut into a predetermined length after demagnetizing a predetermined portion of the cylindrical member 102.
[0022]
Furthermore, since the magnetized valve body 12, the non-magnetized intermediate pipe 13 and the magnetized fuel connector 14 are formed by a single valve housing 11, these three members are brazed or laser welded. This eliminates the troublesome process of joining together, reduces the number of assembly steps, and reduces the manufacturing cost. In addition, the valve body 12, the intermediate pipe 13, and the fuel connector 14 are integrally formed, so that there is no positional deviation during assembly between the three. Therefore, the assembly accuracy can be easily improved, and variations in the injection amount characteristics can be reduced.
[0023]
In the first embodiment, a slit 25 a is provided in the fixed core 25, and the fixed core 25 is fixed to the inner periphery of the fuel connector 14 by press-fitting. By adjusting the press-fitting amount of the fixed core 25, the gap amount between the fixed core 25 and the movable core 24, that is, the lift amount of the needle valve 20 can be easily adjusted. Further, the fixed core 25 may be attached to the fuel connector 14 by means other than press fitting such as caulking.
[0024]
(Second embodiment)
A second 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.
The valve housing 60 includes a cylindrical member 61 as a cylindrical member, a valve body 65, and a sleeve 66 as a connecting member that connects the cylindrical member 61 and the valve body 65. The nozzle hole plate 15 is sandwiched between the valve body 65 and the sleeve 66. The contact portion 21 of the needle valve 20 can be seated on a valve seat 65 a formed on the valve body 65.
[0025]
The cylindrical member 61 includes a valve accommodating portion 62, an intermediate pipe 63 as a non-magnetic portion, and a fuel connector 64 as a fuel suction portion from the nozzle hole 15a side, and is formed in a cylindrical shape having both ends opened. The cylindrical member 61 is formed by cutting a cylindrical member integrally formed in a cylindrical shape into a predetermined length and then demagnetizing a predetermined portion. The cylindrical member 61 and the valve body 65 are laser welded to the sleeve 66 and are connected by the sleeve 66. The sleeve 66 has a simple shape with a bottomed cylinder.
[0026]
In the second embodiment, various lengths on the injection side can be obtained by changing the length of the sleeve without changing the length of the cylindrical member 61, the position of the non-magnetic intermediate pipe 64, and the shape of the valve body 65. A valve housing having a thickness can be easily formed. Therefore, since fuel can be injected at a position close to the intake valve, the atomized fuel spray injected from the fuel injection valve is prevented from adhering to the inner wall of the intake pipe and liquefying, and generation of HC as an unburned component is generated. Can reduce the amount,
In the second embodiment, the cylindrical member 61 is formed by demagnetizing a predetermined portion after being cut to a predetermined length, but the cylindrical member 61 is formed by demagnetizing the predetermined portion and then cutting to a predetermined length. May be.
[0027]
In the second embodiment, the cylindrical member 61 is integrally formed. However, the valve body, the intermediate pipe, and the fuel connector may be formed of separate members, and the cylindrical member may be formed.
In the plurality of embodiments described above, the solid gap is formed by plating the opposing surfaces of the movable core 24 and the fixed core 25, but by making a part of the movable core or the fixed core non-magnetic. A solid gap may be configured. Since the solid gap only needs to be positioned inside the intermediate pipe portion, it is not necessary to demagnetize the facing surface of the movable core or the fixed core. Since the magnetized part has a characteristic that the hardness is higher than the non-magnetic part, if the solid gap is formed by demagnetizing the position away from the opposed surface of the movable core or fixed core, the movable core and fixed core Since the collision surface is magnetized, even if the movable core and the fixed core repeatedly collide, wear and deformation of the movable core and the fixed core can be prevented.
[0028]
In the above-described embodiments, the needle valve 20 is integrally molded. For example, the abutting portion side member, the rod, and the joint portion are formed so that the needle valve can be easily processed according to the length of the valve housing. It is also possible to construct the needle valve with the other member, and to make the needle valve by changing the length of the rod only with the contact member and the joint as the common member.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a fuel injection valve according to a first embodiment of the present invention.
FIG. 2 is an explanatory view showing a manufacturing process of the valve housing of the first embodiment.
FIG. 3 is an explanatory view showing a manufacturing process of the valve housing of the first embodiment.
FIG. 4 is a longitudinal sectional view showing a fuel injection valve according to a second embodiment of the present invention.
[Explanation of symbols]
10 Fuel Injection Valve 11 Valve Housing 12 Valve Body 13 Intermediate Pipe (Nonmagnetic Part)
14 Fuel connector (fuel inlet)
15 Injection hole plate 15a Injection hole 20 Needle valve (valve member)
24 movable core 25 fixed core 30 solenoid 31 electromagnetic coil 60 valve housing 61 cylindrical member 62 valve accommodating part 63 intermediate pipe (non-magnetic part)
64 Fuel inlet (fuel connector)
65 Valve body 66 Sleeve (connecting member)
102 Cylindrical member

Claims (2)

  A fuel suction part is provided on the opening side, a valve body that accommodates a valve member that opens and closes the nozzle hole is provided on the bottom side, and a nonmagnetic part is provided between the fuel suction part and the valve body. A method for manufacturing a fuel injection valve having a bottom cylindrical valve housing, comprising a step of integrally forming a bottomed cylindrical member, cutting an opening side of the bottomed cylindrical member, and extending the bottomed cylindrical member to a predetermined length. A method of manufacturing a fuel injection valve, comprising: forming the valve housing from a step of reducing the height and a step of demagnetizing a portion separated from the opening end of the bottomed cylindrical member by a predetermined distance toward the bottom side. 2. The method of manufacturing a fuel injection valve according to claim 1, wherein the bottomed cylindrical member is formed of either a material that is magnetized before molding or a material that is magnetized in a molding process .

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