JP2007247423A - Method of manufacturing fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a fuel injection valve capable of minimizing the dead volume partitioned by a valve element, a valve body and a nozzle port plate. <P>SOLUTION: This manufacturing method of the fuel injection valve 1 comprises the valve element 12, a valve seat part 61 for seating and leaving the valve element 12, and the valve body 60 having a plate support part 63 supporting the nozzle port plate 70 having a nozzle port 71 and an opening part 62 arranged between the valve seat part 61 and the plate support part 63. The fuel injection valve 1 is manufactured by shaving a tip part 14 or any one of the plate support part 63 and the valve element 12, while seating the valve element 12 on the valve seat part 61 of the valve body 60. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a fuel injection valve.

Conventionally, a valve body, a valve seat portion on which the valve body is attached and detached, a plate support portion for supporting an injection hole plate having injection holes, and a valve seat portion and the plate support portion are provided. A fuel injection valve including a valve body having an opening is known (Patent Document 1).
Japanese Patent Laid-Open No. 2004-19610

  Usually, a fuel injection valve is manufactured by processing a valve body or a valve body as a single item, and then assembling the components. When the fuel injection valve is manufactured in this way, the machining errors of the respective parts are accumulated, and when the valve body is seated on the valve body, the tip of the valve body comes into contact with the injection hole plate. In order to prevent this, the dimensions of the valve body and the valve body are determined in consideration of processing errors of each component. As a result, the space defined by the surface of the valve body, the inner wall of the valve body, and the surface of the nozzle hole plate (hereinafter also referred to as dead volume) naturally increases.

  On the other hand, in the case of an internal combustion engine in which a fuel injection valve having a dead volume is attached to the intake pipe, the fuel in the dead volume is sucked out by the intake negative pressure even though the injection valve is closed after the end of the injection. As a result, there arises a problem that the injection amount increases from the planned injection amount. This problem becomes more prominent as the dead volume increases, which adversely affects combustion.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a fuel injection valve capable of reducing the dead volume defined by the valve body, the valve body, and the injection hole plate as much as possible. It is to provide.

  According to the first aspect of the present invention, the valve body, the valve seat part on which the valve body separates and seats, the plate support part for supporting the nozzle hole plate having the nozzle holes, and between the valve seat part and the plate support part In a method of manufacturing a fuel injection valve including a valve body having an opening provided in the plate, the plate support portion and the tip end portion of the valve body, or any one of them while the valve body is seated on the valve seat portion of the valve body It is characterized by cutting one side.

  In the conventional method for manufacturing a fuel injection valve, the valve body and the valve body are processed separately, so that when each part is assembled thereafter, the processing error of each part is integrated, and in some cases the dead volume is increased. There was.

  On the other hand, according to the present invention, the plate support portion and / or the tip end portion of the valve body are scraped while the valve body is seated on the valve seat portion of the valve body, so that the conventional technique is used. Processing errors are not accumulated. For this reason, the precision of the relative position of the axial direction of a plate support part and the front-end | tip part of a valve body can be improved. As a result, the dead volume when the nozzle hole plate is attached to the plate support portion can be made as small as possible.

  According to a second aspect of the present invention, in the method of manufacturing a fuel injection valve according to the first aspect, the plate support portion of the valve body and the tip end portion of the valve body are made to coincide with each other in the axial direction.

  According to the present invention, the nozzle hole plate is supported between the nozzle hole plate and the plate support portion by a component such as a shim that is simpler in shape than the valve body or valve body and relatively easy to improve processing accuracy. The dead volume can be made as small as possible.

  According to a third aspect of the present invention, in the method of manufacturing a fuel injection valve according to the second aspect, both the plate support portion of the valve body and the tip end portion of the valve body are shaved to pivot the plate support portion and the tip end portion. It is characterized by matching the direction position.

  According to the present invention, since both the plate support portion of the valve body and the tip end portion of the valve body are scraped simultaneously, the processing accuracy of the plate support portion of the valve body and the tip end portion of the valve body up to this step is achieved. Since it is no longer necessary to increase the manufacturing cost, an increase in manufacturing cost can be suppressed.

  According to the fifth aspect of the present invention, in the method of manufacturing the fuel injection valve according to the fourth aspect, either the plate support part of the valve body or the tip part of the valve body is shaved to remove the plate support part from the tip part. Is also located on the downstream side of the fuel.

  According to this invention, since the injection hole plate having a flat plate-like simple structure can be attached to the valve body, an increase in the manufacturing cost of the fuel injection valve can be suppressed.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the structure and operation of the fuel injection valve manufactured by the manufacturing method of the present embodiment will be described with reference to FIGS. FIG. 1 is a vertical cross-sectional view of the fuel injection valve of the present embodiment, and FIG. 2 is a cross-sectional view of the main part near the injection hole of the fuel injection valve of FIG.

  The fuel injection valve 1 of the present embodiment is attached to, for example, an intake pipe (not shown) of an internal combustion engine, and a fuel pump (not shown) from a fuel tank (not shown) based on a command signal from an ECU (not shown). ) Is an injection valve that measures the fuel pumped up. As shown in FIG. 1, the fuel injection valve 1 includes a valve unit 10, a nozzle unit 20 that houses the valve unit 10, and an actuator unit 30 that drives the valve unit 10. The valve unit 10 is accommodated in the nozzle unit 20 so as to be able to reciprocate. When the actuator unit 30 drives the valve unit 10, the amount of fuel injected from the tip of the nozzle unit 20 is adjusted, and an appropriate fuel is supplied. Is supplied to the combustion chamber.

  The nozzle unit 20 includes a magnetic pipe 21 and a housing 25. A valve body 60 and an injection hole plate 70 facing the intake pipe are attached to one end portion of the housing 25, and a magnetic pipe 21 that holds the actuator portion 30 is attached to the opposite end portion. The magnetic pipe 21 includes a magnetic member and a nonmagnetic member, and is formed in a substantially cylindrical shape. In FIG. 1, the first magnetic member 22, the nonmagnetic member 24, and the second magnetic member 23 are arranged in this order from the lower housing 25 side. Have. The first magnetic member 22 and the nonmagnetic member 24, and the nonmagnetic member 24 and the second magnetic member 23 are joined by welding. The welding is performed by, for example, laser welding. The nonmagnetic member 24 is for preventing the magnetic flux from being short-circuited between the first magnetic member 22 and the second magnetic member 23.

  A fuel passage 80 is provided inside the substantially cylindrical magnetic pipe 21. A stator 34 and a mover 35 are accommodated on the inner wall of the magnetic pipe 21 from above in FIG. 1, and a coil spring 40 and an adjusting pipe 50 are accommodated on the inner walls of the stator 34 and the mover 35. Yes. The stator 34, the mover 35, the coil spring 40, and the adjusting pipe 50 are all formed in a substantially cylindrical shape, and allow the fuel flowing from the fuel passage 80 above the magnetic pipe 21 to pass below the magnetic pipe 21. It is like that. As shown in FIG. 1, the stator 34 is fixed to the magnetic pipe 21 by welding after being inserted into the inner walls of the nonmagnetic member 24 and the second magnetic member 23. An electromagnetic coil 31 as a part of the actuator unit 30 is held outside the magnetic pipe 21.

  The housing 25 is made of a magnetic material and has a substantially cylindrical shape. A first magnetic member 22 is fixed above the housing 25 by welding. The inside of the housing 25 communicates with the fuel passage 80 so that the fuel flowing in from the fuel passage 80 flows to the tip of the housing 25.

  As shown in FIG. 2, a bottomed cylindrical valve body 60 is attached below the housing 25. Below that, an injection hole plate 70 in which a plurality of injection holes 71 are formed is attached to the distal end surface of the valve body 60 via a shim 72. This front end surface is called a plate support portion 63. Inside the valve body 60, a valve seat portion 61 on which the tip of the valve portion 10 can be seated is formed, and an opening 62 is formed below the valve seat portion 61.

  The valve unit 10 includes a needle 11 and a valve body 12. The valve body 12 is formed below the needle 11, and an abutting portion 13 that is separated from the valve seat portion 61 is formed. Above the needle 11, the mover 35 is fixed by welding. When the contact portion 13 is seated on the valve seat portion 61, the supply of fuel to the nozzle hole 71 is stopped and fuel is no longer injected from the nozzle hole 71.

  Here, the valve body 12 and the valve body 60 are dimensioned such that the distal end portion 14 of the valve body 12 does not contact the injection hole plate 70 in a state where the contact portion 13 is seated on the valve seat portion 61. In the case of this embodiment, the axial direction positions of the front end portion 14 and the plate support portion 63 are matched, and a shim 72 having a predetermined thickness is interposed between the plate support portion 63 and the nozzle hole plate 70. Thus, the nozzle hole plate 70 is attached to the valve body 60. Thereby, when the contact part 13 of the valve body 12 is seated on the valve seat part 61, the tip part 14 can be prevented from coming into contact with the injection hole plate 70 and the injection hole plate 70 being deformed. At this time, the valve body 12, the valve body 60, and the nozzle hole plate 70 define a space 81 having a predetermined volume (hereinafter referred to as a dead volume).

  The adjusting pipe 50 is press-fitted into the inner wall of the stator 34. One end of the coil spring 40 is in contact with the adjusting pipe 50, and the other end is in contact with the mover 35. The coil spring 40 always urges the movable element 35 downward, and the urging force on the movable element 35 can be adjusted by adjusting the amount of press-fitting of the adjusting pipe 50.

  The magnetic member 26 is magnetically connected to the housing 25 and is provided on the outer peripheral side of the electromagnetic coil 31. Thereby, the stator 34, the mover 35, the first magnetic member 22, the housing 25, the magnetic member 26 and the second magnetic member 23 constitute a magnetic circuit.

  A spool 32 around which the electromagnetic coil 31 is wound is attached to the outer periphery of the magnetic pipe 21. The terminal 33 is electrically connected to the electromagnetic coil 31, and a drive current is supplied to the electromagnetic coil 31 based on a command signal from the ECU. The resin housing 90 covers the outside of the magnetic pipe 21 and the electromagnetic coil 31.

  When no driving current is supplied to the electromagnetic coil 31, no magnetic attractive force is generated between the stator 34 and the mover 35. Therefore, the mover 35 moves away from the stator 34 by the urging force of the coil spring 40, that is, moves downward. Thereby, the contact part 13 of the valve body 12 integral with the needle | mover 35 is seated on the valve seat part 61, and the injection of the fuel from the nozzle hole 71 stops.

  When a drive current is supplied to the electromagnetic coil 31, the electromagnetic coil 31 is excited, and the stator 34, the mover 35, the first magnetic member 22, the housing 25, the magnetic member 26, and the second magnetic member 23 are magnetized. A circuit is formed. Thereby, a magnetic attractive force is generated between the stator 34 and the movable element 35. When the magnetic attractive force generated between the stator 34 and the mover 35 becomes larger than the urging force of the coil spring 40, the mover 35 moves toward the stator 34. The mover 35 moves until it collides with the stator 34. Therefore, the valve portion 10 integrated with the mover 34 moves upward in FIG. 1, and the contact portion 13 is separated from the valve seat portion 61. When the contact portion 13 is separated from the valve seat portion 61, the fuel flows through the passage formed between the valve body 12 and the valve seat portion 61 to the injection hole 71, and the fuel is injected from the injection hole 71.

  When the supply of the drive current to the electromagnetic coil 31 is stopped again, the magnetic attractive force between the stator 34 and the mover 35 disappears. Therefore, the mover 35 moves again away from the stator 34 by the biasing force of the coil spring 40. As a result, the contact portion 13 is seated on the valve seat portion 61, and fuel injection from the injection hole 71 is stopped.

  Next, a processing apparatus and a manufacturing method for processing the valve body and the valve body portion of the fuel injection valve of the present embodiment will be described. FIG. 3 is a processing apparatus for processing the valve body and the valve body portion of the fuel injection valve according to the first embodiment. FIG. 4 is a view showing a valve body processed by the processing apparatus of FIG. 3 and a manufacturing process of the valve body.

  As shown in FIG. 3, the processing apparatus 100 mainly includes a pressurizing unit 110 that pressurizes the needle 11 and the valve body 12 downward, a valve body 60, and the contact portion 13 of the valve body 12 of the valve body 12. A disc-like shape that supports the valve seat 61 while being seated and guides the needle 11 so as to be movable in the axial direction, the plate support 63 of the valve body 60 and the tip 14 of the valve body 12 simultaneously. It comprises a grindstone 130 and a motor 140 that rotates the grindstone 130.

  The pressurizing unit 110 is located above the needle 11 and is provided at a position to move the needle 11 while pressurizing it downward. On the other hand, a grindstone 130 is provided below the needle 11 so that the plate support 63 of the valve body 60 and the tip 14 of the valve body 12 can be cut. A motor 140 that rotates the grindstone 130 is provided below the grindstone 130, and a guide unit 120 is provided between the grindstone 130 and the pressure unit 110.

  Here, before describing the manufacturing method of the present embodiment, the conventional manufacturing process of the valve body and the valve body will be described. In a conventional method for manufacturing a fuel injection valve, a valve body, a valve body, an injection hole plate, and the like are processed in separate processing steps, and after being processed, a method of assembling each component has been adopted.

  With the conventional manufacturing method described above, even if the machining error that occurs during each machining process is very small, each part is assembled into a fuel injection valve, and the valve body is seated on the valve body. In this case, the axial positions of the plate support portion of the valve body and the tip end portion of the valve body may accumulate the respective processing errors, so that the tip end portion of the valve body may come into contact with the nozzle hole plate. For this reason, the dimensions of the respective parts are usually determined with a certain margin so that the machining errors of the respective parts are integrated when the respective parts are assembled, and the above-mentioned problems are not caused.

  However, if the dimensions of each part are determined based on the above concept, a so-called dead volume divided by the valve body, the valve body, and the nozzle hole plate tends to increase.

  By the way, in the case of an internal combustion engine in which a fuel injection valve having a dead volume is attached to the intake pipe, the fuel in the dead volume is sucked out by the negative intake pressure even after the injection is finished, even though the injection valve is closed. As a result, there arises a problem that the injection amount increases from the planned injection amount. This problem becomes more prominent as the dead volume increases, which adversely affects combustion. Further, the larger this dead volume, the more the atomization of fuel is inhibited when the injection valve is opened. However, there is a limit to reducing the dead volume for the above manufacturing reasons.

  Next, the manufacturing process of the fuel injection valve of this embodiment will be described. 4A is a cross-sectional view of the valve body and the valve body before being processed by the processing apparatus shown in FIG. 3, and FIG. 4B is the valve body and the valve body after being processed by the processing apparatus shown in FIG. FIG. 4C is a cross-sectional view of the valve body and the valve body attached to the injection hole plate after the end of processing.

  As shown in FIG. 4A, the valve body 60 and the valve body 12 processed in separate manufacturing processes are installed in the processing apparatus 100. At this time, the processing device 100 is installed so that the contact portion 13 of the valve body 12 is seated on the valve seat portion 61 of the valve body 60. At this time, as shown in FIG. 4A, the axial positions of the plate support portion 63 and the tip end portion 14 of the valve body 12 do not coincide with each other yet.

  Then, the pressurization part 110 of the processing apparatus 100 is operated, and the valve body 60 and the valve body 12 are moved below. At the same time, the motor 140 is operated to rotate one grindstone 130, and the plate support portion 63 and the tip end portion 14 of the valve body 12 are simultaneously shaved. Cutting is performed until the plate support 63 and the tip 14 are in the state shown in FIG. 4B, that is, until the plate support 63 and the tip 14 coincide with each other in the axial position. Then, the valve body 60 and the valve body 12 are taken out from the processing apparatus 100, and the nozzle hole plate 70 is attached to the plate support part 63 via the shim 72 (see FIG. 4C).

  In this embodiment, the processing apparatus 100 matches the axial positions of the plate support portion 63 and the tip portion 14 and attaches the nozzle hole plate 70 via the shim 72. The shim 72 is a component that is simpler in shape than the valve body 60 and the valve body 12 and relatively easy to improve machining accuracy. For this reason, the dead volume 81 can be made as small as possible.

  According to the manufacturing method of the present embodiment, the valve body 60 and the valve body 12 are simultaneously processed with one tool (the grindstone 130 in the present embodiment), specifically, the valve seat portion of the valve body 60. In the state where the contact portion 13 of the valve body 12 is seated on 61, the plate support portion 63 and the tip portion 14 are simultaneously processed so that the axial positions of the plate support portion 63 and the tip portion 14 are matched. . For this reason, unlike the conventional manufacturing method, since it is not necessary to consider the integration of machining errors of the valve body 60 and the valve body 12, the axial positions of the plate support portion 63 and the tip portion 14 can be easily matched with high accuracy. Can be made. As a result, the thickness of the shim 72 interposed between the plate support 63 and the nozzle hole plate 70 can be made as thin as possible, and as a result, the dead volume 81 can be made as small as possible.

  According to the present embodiment, the nozzle hole plate 70 is attached to the valve body 60 via the shim 72. The thickness of the shim 72 does not contact the nozzle hole plate 70 even if the valve body 60 and the valve body 12 change with time so that the tip part 14 of the valve body 12 protrudes below the plate support part 63. It is determined to the extent. Since the shape of the shim 72 is very simple compared to the valve body 60 and the valve body 12, the machining accuracy of the shim 72 can be easily increased as compared to the valve body 60 and the valve body 12. For the above reasons, the thickness of the shim 72 can be made as thin as possible.

  Further, according to the manufacturing method of the present embodiment, the dead volume 81 itself can be reduced in size, and the variation thereof can also be reduced. As a result, the variation in the injection characteristics of the fuel injection valve 1 can be reduced.

  Moreover, in the manufacturing method of this embodiment, since the plate support part 63 and the front-end | tip part 14 are processed simultaneously, the plate support part 63 and the front-end | tip part are processed at the time of the process of the valve body 60 and the valve body 12 until it reaches this process. Since it is not necessary to raise the processing accuracy of 14, it is possible to suppress an increase in the manufacturing cost of the fuel injection valve 1.

  Further, the injection hole plate 70 attached to the valve body 60 may be an injection hole plate 70a as shown in FIG. The nozzle hole plate 70 a has a structure in which a portion facing the opening 62 of the valve body 60 is slightly recessed with respect to the plate support 63. That is, the nozzle hole plate 70a is formed by connecting the nozzle hole plate 70a to the plate support portion 63 and seating the contact portion 13 on the valve seat portion 61. The structure is such that a gap is formed between them. According to this nozzle hole plate 70a, there is no need to attach the nozzle hole plate via the shim 72, so that the number of parts can be reduced.

(Second Embodiment)
Next, a manufacturing method according to the second embodiment will be described. FIG. 6 shows a processing apparatus for processing the valve body and the valve body portion of the fuel injection valve according to the second embodiment. FIG. 7 is a diagram illustrating a valve body processed by the processing apparatus of FIG. 6 and a manufacturing process of the valve body.

  As shown in FIG. 6, the processing apparatus 100 a is different from the processing apparatus 100 used in the manufacturing method of the first embodiment in a portion for cutting the tip portion 14 of the valve body 12.

  The motor 140 is provided with a grindstone 130a. The grindstone 130a has a substantially cylindrical shape, and the outer diameter thereof is smaller than the opening 62 of the valve body 60, and the distal end portion 14 of the valve body 12 in a state where the contact portion 13 is seated on the valve seat portion 61. Can be shaved (see FIG. 7A).

  A stopper 150 is provided on the outer wall of the motor 140. The stopper 150 stops the progress of the grindstone 130a. Since the tip of the stopper 150 is slightly lower than the end of the grindstone 130a, the axial position of the plate support 63 can be lower than the tip 14, that is, the fuel downstream side (FIG. 7). (See (b)).

  According to this processing apparatus 100a, since the axial position of the plate support 63 can be set downstream of the fuel with respect to the tip end portion 14, the nozzle hole plate is attached via the shim or the nozzle hole provided with a recess. There is no need to attach a plate, and by attaching only the flat injection hole plate 70b to the valve body 60, an appropriate gap can be provided between the tip portion 14 and the injection hole plate 70b. The increase in the manufacturing cost of 1 can be suppressed.

  In addition, although the processing apparatus 100a in this embodiment is an apparatus which cuts only the front-end | tip part 14 of the valve body 12, you may make it cut only the plate support part 63 of the valve body 60. FIG.

It is a longitudinal cross-sectional view of the fuel injection valve manufactured with the manufacturing method by 1st Embodiment of this invention. It is principal part sectional drawing of the fuel injection valve manufactured with the manufacturing method by 1st Embodiment of this invention. It is principal part sectional drawing of the nozzle hole vicinity of the fuel injection valve of FIG. It is a processing apparatus which processes the valve body and valve body of the fuel injection valve of FIG. It is a figure which shows the manufacturing process of the valve body processed with the processing apparatus of FIG. 3, and a valve body. It is a modification of the fuel injection valve manufactured with the manufacturing method by 1st Embodiment of this invention. It is the processing apparatus which processes the valve body and valve body of the fuel injection valve manufactured with the manufacturing method by 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the valve body processed with the processing apparatus of FIG. 6, and a valve body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve 10 Valve part 11 Needle 12 Valve body 13 Contact part 14 Tip part 20 Nozzle part 21 Magnetic pipe 22 1st magnetic member 23 2nd magnetic member 24 Nonmagnetic member 25 Housing 26 Magnetic member 30 Actuator part 31 Electromagnetic coil 32 spool 33 terminal 34 stator 35 mover 40 coil spring 50 adjusting pipe 60 valve body 61 valve seat 62 opening 63 plate support 70 nozzle hole plate 71 nozzle hole 72 shim 80 fuel passage 81 space (dead volume)
DESCRIPTION OF SYMBOLS 90 Resin housing 100 Processing apparatus 110 Pressurization part 120 Guide part 130 Grinding wheel 140 Motor 150 Stopper

Claims (5)

The disc,
A valve seat portion from which the valve body is seated and detached; a plate support portion for supporting an injection hole plate having an injection hole; and a valve body having an opening provided between the valve seat portion and the plate support portion. In the manufacturing method of the fuel injection valve provided,
A method for manufacturing a fuel injection valve, wherein the plate support portion and / or the tip end portion of the valve body are shaved while the valve body is seated on the valve seat portion of the valve body. In the manufacturing method of the fuel injection valve according to claim 1,
A method for manufacturing a fuel injection valve, wherein the plate support portion of the valve body and the tip end portion of the valve body are aligned at an axial position. In the manufacturing method of the fuel injection valve according to claim 2,
A method for manufacturing a fuel injection valve, wherein both the plate support portion of the valve body and the tip end portion of the valve body are shaved so that the plate support portion and the tip end portion are aligned in the axial direction. In the manufacturing method of the fuel injection valve according to claim 1,
A method for manufacturing a fuel injection valve, wherein the plate support portion of the valve body is positioned on the fuel downstream side of the tip portion of the valve body. In the manufacturing method of the fuel injection valve according to claim 4,
Either the plate support part of the valve body or the tip part of the valve body is scraped to position the plate support part on the fuel downstream side of the tip part. .

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