JP3873071B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve in which precision parts composed of a plurality of members are combined.

  An example of conventional nozzle assembly will be described using Japanese Patent Publication No. 7-10471 as a method for concentric coupling of precision parts composed of a plurality of members. In FIG. 1 of the publication, a taper hole (valve seat) 10c is formed in the inner bottom of the nozzle body (outer cylindrical part) 10 provided with an orifice 11, and a swirler with a through hole 12a is formed in the nozzle body 10. (Inner cylindrical part) 12 is installed while securing a clearance, and the swirler 12 and the nozzle body 10 are fitted by the punch 16 while the taper hole 10c and the through hole 12a of the swirler 12 are centered by the positioning guide pin 14. The vicinity of the joint (swirler 12 side) was pressed so that local plastic flow occurred, and both parts were concentrically joined by the force of this plastic flow. A fuel turning force generating groove for turning the fuel is formed inside the swirler 12, and the fuel is injected from the fuel injection valve while turning.

Japanese Patent Publication No. 7-10471

  By the way, as in the prior art, a swirler 12 of an inner cylindrical part is installed in an outer cylindrical part such as the nozzle body 10 while securing a clearance G between the two parts, and a taper hole is formed by a positioning guide pin 14. 10c and the through hole 12a of the swirler 12 are centered, and the punch 16 is pressed in the vicinity of the fitting portion of the swirler 12 so that local plastic flow occurs, and both parts are concentric by the force of this plastic flow. In the case of bonding, residual stress due to plastic flow is always generated in the bonded portion.

  If the coaxiality of the inner and outer diameters of the swirler 12 is 0, and the coaxiality of the inner diameter of the nozzle body 10 and the tapered hole 10c is 0, the residual stress is uniformly generated on the entire circumference, and ideal concentric coupling is achieved. I can do it. However, if either one of the two parts is shaken, that is, if the coaxiality is not zero, or if the coaxiality between the outer diameter and the inner diameter of the swirler 12 is not zero, the dimension of the clearance G of the entire circumference is partially In contrast, the residual stress around the entire joint is unbalanced. For this reason, if the positioning guide pin 14 is removed, the springback amount of the entire circumference differs due to imbalance, and misalignment occurs. As described above, in the conventional method, the influence of the single unit accuracy of the parts on the coaxiality after the coupling remains not a little. In the example of the publication, as shown in FIG. 5 of the publication, the concentricity after coupling is 5.8 μm on average.

  Further, when the nozzle body 10 and the swirler 12 are both a combination of materials that cannot be plastically flowed, such as a quenching material, it is impossible to connect both parts using plastic flow. Cannot be adopted.

  An object of the present invention is to provide a fuel injection valve composed of a plurality of members that is not affected by the accuracy of individual parts and that can maintain the coaxiality after the coupling.

  In order to achieve the above object, according to the present invention, a swirler is sandwiched between a plate fixed to the inner periphery of the nozzle of the fuel injection valve and a seat portion provided at the tip of the nozzle.

  More specifically, when the swirler is fixed to the nozzle body concentrically, the swirler is mounted on the bottom inside the nozzle body while ensuring a clearance between the inner diameter portion of the nozzle body and the outer diameter portion of the swirler. The two were fitted in a state of being placed, and a plate for fixing the swirler so as to sandwich the swirler in a sandwich shape was fitted on the upper surface of the swirler.

  The swirler that requires high coaxiality with the nozzle orifice is only sandwiched between the plate and the nozzle and fixed, and the springback does not act after fixing, so the nozzle orifice and swirler maintain high coaxiality. Be drunk.

Example 1
Embodiments of the present invention will be described with reference to the drawings.

  FIG. 7 is a longitudinal sectional view of a fuel injection valve for an automobile gasoline engine to which the present invention is applied.

The main part of the fuel injection valve body 1 includes a magnetic circuit including a core 41, a yoke 42 and a movable valve 43, a coil 48 for exciting the magnetic circuit, and a terminal bobbin 49 for energizing the coil 48. Inside the core 41 is a movable valve 43 having a valve seat 43a at the tip, a spring 44 that presses the seat portion 10c of the nozzle 10, an adjuster 45 that adjusts the pressing load of the spring 44, and a stroke end of the movable valve 43. There are a stopper 46, a swirler 12 that gives a turning force to the fuel, a plate 13 that fixes the swirler 12 to the nozzle 10, a ring 47 that prevents the fuel from leaking between the core 41 and the yoke 42 and supports the dry coil structure. is doing.

  When the coil 48 of the fuel injection valve body 1 is energized, the movable valve 43 moves in the direction of the core 41 against the biasing force of the spring 44, and between the ball valve 43 d at the tip of the movable valve 43 and the orifice 11. There is a gap. The pressurized fuel passes through the core 41, the adjuster 45, the ring 47, the fuel passages 43b and 43c in the movable valve, the fuel passage 10b of the nozzle 10, the fuel passage 13b of the plate 13, and swirls by the swirler groove 12b of the swirler 12. A force is applied and it is injected from the orifice 11. On the other hand, when the current of the coil 48 is interrupted, the ball valve 43d of the movable valve 43 comes into contact with the seat portion 10c by the force of the spring 44, and the valve is closed.

  A method for assembling and assembling the nozzle 10 that is the outer cylindrical part of the fuel injection valve body 1 having the above-described configuration, and the swirler 12 and the plate 13 that are incorporated therein and are the inner cylindrical part will be described below.

  1 is a first embodiment of the present invention, which is a longitudinal sectional view showing the steps of the method of connecting the components of the fuel injection valve shown in FIG. 7, FIG. 2 is a longitudinal sectional view of the punch 16, and FIG. FIG. 4 is a longitudinal sectional view of the plate 13, the swirler 12, and the nozzle 10 after being pressed by the punch 16, FIG. 4 is a longitudinal sectional view of the jig and work machine showing the operation of the component joining method shown in FIG. These are the line graphs which compared the coaxiality of the nozzle and swirler at the time of employ | adopting the coupling | bonding method by 1st Example, and the coaxiality at the time of employ | adopting the conventional method.

  (I) of FIG. 1 is a longitudinal sectional view of the nozzle 10, the swirler 12, and the plate 13 that are components to be joined. The nozzle 10 has a sheet portion 10c, the swirler 12 has an inner diameter portion 12a, and the plate 13 has a through hole 13a.

  FIG. 1 (II) shows a state where the above components are combined. First, the swirler 12 is fitted into the nozzle 10 with a clearance G between the inner and outer diameters, and the plate 13 is fitted to the upper portion of the swirler 12 so as to sandwich the swirler 12 in a sandwich shape. In addition, A in a figure shows the fitting location of the plate 13. FIG.

Next, in this fitted state, as shown in FIG. 1 (III), the inner diameter portion 12a of the swirler 12 is substantially the same diameter as this inner diameter, so that a gap is maintained rather than the inner diameter of the through hole 13a of the plate 13. The positioning pin 14 having a small outer diameter is pushed in until the pin tip 14a contacts the sheet portion 10c of the nozzle 10. The positioning pin 14 abuts against the tapered sheet portion 10c on the inner bottom of the nozzle 10, whereby the sheet portion 10c and the inner diameter portion 12a of the swirler 12 are temporarily positioned in a concentric state. In this temporary positioning, if there is a misalignment between the seat portion 10c and the inner diameter portion 12a of the swirler 12 at the stage (II) in FIG. 1, the clearance G absorbs this misalignment. .

  Next, in this temporarily positioned state, as shown in FIG. 1 (IV), a mechanical local pressing force is applied to the fitting portion A of the plate 13 to generate a plastic flow at the pressing portion. As shown in FIGS. 1 (III) to (IV), this mechanical pressing is performed by pressing the plate 13 and the swirler 12 into the nozzle 10 with the presser 15 with the positioning pin 14 inserted into the inner diameter portion 12a of the swirler 12. The fixing is performed by pressing the vicinity of the outer diameter of the plate 13 with the protrusion 16a provided at the tip of the punch 16 shown in FIG. As a result, as shown in FIG. 3, the plate 13 after being pressed by the punch 16 is plastically coupled to the nozzle 10 in a state where the swirler 12 is pressed in the direction of the sheet portion 10 c of the nozzle 10.

  In FIG. 4, when the press machine is used as the work machine and the above-described joining method is performed, first, the nozzle 10, the swirler 12, and the plate 13 are inserted and set in the receiver 33 and the receiver 35. A ram 36 of the press machine is provided with a presser 31, a presser 32, a backing plate 38, a punch holder 39, a positioning pin 14, a presser 15, a punch 16, a sub cylinder 40, a presser spring 34, and the like. The presser 15 and the punch 16 are arranged concentrically on the outer periphery of the positioning pin 14. The positioning pin 14 is attached to the sub-cylinder 40 and moves up and down as the sub-cylinder 40 moves up and down. The presser 15 is pressed in the direction of the receiver 35 by the presser spring 34, and other parts move up and down as the ram 36 moves up and down.

  The sub-cylinder 40 is lowered to lower the positioning pin 14, and the positioning pin 14 is pushed into the inner diameter portion 12 a of the swirler 12 until the pin tip 14 a contacts the sheet portion 10 c of the nozzle 10. The presser 15 fixes the plate 13 and the swirler 12 to the nozzle 10 by the force of the presser spring 34. In this state, the ram 36 is lowered, the punch 16 is moved along the outer periphery of the positioning pin 14, and the protrusion 16 a of the punch 16 comes into contact with the plate 13. When a force for lowering the ram 36 is further applied, a plastic flow is generated at the fitting portion A in the vicinity of the outer diameter of the upper surface of the plate 13, and the tightening force and the shearing force due to the plastic flow act on the inner diameter side of the nozzle 10. The nozzle 10 and the plate 13 are coupled together with 12 being sandwiched. For strong coupling, a coupling groove may be provided in either one of the fitting portions of the nozzle 10 or the plate 13. Alternatively, if the material of the plate 13 is softer than the material of the nozzle 10, good bonding can be obtained.

  After the coupling, the sub-cylinder 40 is raised while raising the ram 36, the positioning pins 14 are extracted from the swirler 12, and the ram 36 is further raised to complete the process.

  As described above, according to the first embodiment, when the swirler 12 is assembled into the nozzle 10, the plate 13, the nozzle 10, and the swirler 12 are combined using a press machine, and the combined sheet of the nozzle 10 is combined. The coaxiality between the portion 10c and the inner diameter portion 12a of the swirler 12 can be kept good.

  When the fuel injection valve is manufactured by the above process, the coaxiality of the seat portion 10c of the nozzle 10 of the fuel injection valve and the inner diameter portion 12a of the swirler 12 shown in FIG. The contact of the ball valve 43d of the movable valve 43 with the portion 10c can be ensured, and fuel leakage can be prevented. In addition, since the annular gap between the seat portion 10c and the ball valve 43d when the valve is opened can be made uniform, uneven fuel spray can be eliminated. Further, since the swirler 12 is not directly pressed and coupled, the thickness of the swirler 12 can be reduced, and the size can be reduced. Furthermore, even if the coaxiality of the inner and outer diameters of the swirler 12 is, for example, 20 μm or more, a good coaxiality with the sheet portion 10c can be obtained after the coupling, so the swirler 12 does not require precision processing such as grinding, It can be manufactured by an inexpensive manufacturing method for sintered parts and the like. For example, the swirler 12 may be a material having wear resistance such as a hardened material, a cemented carbide material, a ceramic material, or a surface treatment having wear resistance.

  FIG. 5 is a line graph showing the results of comparing and comparing the coaxiality data obtained by the conventional method with the coaxiality of the seat portion 10c and the inner diameter portion 12a of the swirler 12 when combined according to the first embodiment. The horizontal axis in FIG. 5 is the number of product samples, and the vertical axis is the coaxiality. In the conventional method, the average is 5.8 μm, but according to the first embodiment, the average is 1.5 μm, and a very high coaxiality can be achieved.

(Example 2)

  FIG. 6 shows a second embodiment of the present invention, and is a longitudinal sectional view showing the steps of the method for connecting the components of the fuel injection valve shown in FIG.

In the second embodiment, instead of the orifice 11 of the nozzle 10 of the first embodiment shown in FIG. 1, a cylindrical hole 51a is provided in the outer cylindrical part 51 as shown in FIG. 6 (I). It is. Further, the sheet portion 10c of FIG. 1 is not provided. This is not a structure in which the fuel injection valve targeted by the second embodiment is provided with a ball valve 43d on the movable valve 43 as shown in FIG. 7 and the ball valve 43d and the seat portion 10c open and close the valve. This is because a spindle type valve (not shown) is inserted into the cylindrical hole 51a of FIG. The inner diameter portion 52 a of the inner cylindrical part 52 having such a configuration is set to be larger than the inner diameter of the cylindrical hole 51 a of the outer cylindrical part 51.

  When positioning the outer cylindrical part 51, the inner cylindrical part 52, and the plate 53, as shown in (I) to (III) of FIG. 6, the positioning pin 54 is moved from the inner diameter part 52 a side of the inner cylindrical part 52. It is necessary to center the inner diameter part 52a and the cylindrical hole 51a by inserting them into the cylindrical hole 51a of the outer cylindrical part 51. Therefore, in this embodiment, the positioning pin 54 has a first portion 54a having substantially the same diameter as the inner diameter portion 52a and a second portion 54b having substantially the same diameter as the cylindrical hole 51a. Thus, a step is provided at the boundary between the first portion 54a and the second portion 54b having different diameters. The pin tip 54c of the positioning pin 54 is tapered and tapered to guide the insertion. For this reason, even when a misalignment occurs between the cylindrical hole 51a of the outer cylindrical part 51 and the inner diameter part 52a of the inner cylindrical part 52, when the positioning pin 54 is inserted, When the first portion 54a and the inner diameter portion 52a come into contact with the cylindrical hole 51a and the inner cylindrical part 52 moves in the lateral direction with the clearance G, the misalignment can be absorbed.

  Thereafter, as shown in FIG. 6 (IV), if a local plastic flow is generated at the fitting position A of the plate 53 by the punch 16, the outer cylindrical part 51 and the inner cylindrical part 52 are sandwiched between the inner cylindrical part 52 and the inner cylindrical part 52. The plate 53 is connected. In this case, since the punch 16 is moved and guided along the outer periphery of the positioning pin 54 in the same direction as the positioning pin 54, the inner cylindrical part 52 is pressed against the bottom of the outer cylindrical part 51 via the plate 53. Fixed.

  As described above, according to the second embodiment, while maintaining the coaxiality of the inner cylindrical part 52 and the outer cylindrical part 51 without being affected by the single part accuracy of the part or the springback due to the residual stress, The inner cylindrical part 52, the plate 53, and the outer cylindrical part 51 can be fixed. Further, since the plate 53 can be plastically flowed, the materials of the outer cylindrical part 51 and the inner cylindrical part 52 can be freely combined.

  According to the present invention, as described in the above embodiments, the positioning accuracy between precision parts is improved, and the outer cylindrical part and the inner cylindrical part are quickly combined with a pressing machine such as a press machine. Since it is excellent in mass production that can automatically perform the assembly work, and the degree of freedom of the combination of the component materials can be increased, the durability of the sliding portion of the fuel injection valve can be improved. Further, after the coupling, the amount of springback of the entire circumference of the inner cylindrical part does not change due to the imbalance of the residual stress at the time of fixing, so that the coaxiality can be maintained, and it is not necessary to consider the accuracy of each part. Since the coaxiality is maintained, the movable valve can be stably operated, and uneven fuel spray can be eliminated. Furthermore, the outer cylindrical part and the inner cylindrical part can be thinned, and the fuel injection valve can be reduced in size and weight.

Embodiment 1
When incorporating an inner cylindrical part having a through hole at the center into an outer cylindrical part with a bottom having a tapered hole at the center of the inner bottom,
The inner cylindrical part is fitted on the bottom inside the outer cylindrical part while ensuring a clearance between the inner diameter part of the outer cylindrical part and the outer diameter part of the inner cylindrical part. Together
Fitting the second inner cylindrical part to the outer cylindrical part so as to sandwich the inner cylindrical part between the inner bottom of the outer cylindrical part and the second inner cylindrical part;
In this fitted state, a positioning pin in which the centering surface and the insertion guide surface of the tapered hole are formed at the tip of the through-hole of the inner cylindrical part and approximately the same diameter as the through-hole, Insert until the tip contacts the tapered hole of the outer cylindrical part, perform concentric temporary positioning of the through hole of the inner cylindrical part and the tapered hole of the outer cylindrical part,
In the temporary positioning state, the punch is moved and guided along the outer periphery of the guide pin in the same direction as the insertion direction of the guide pin, and any one of the second inner cylindrical part and the outer cylindrical part is guided by the punch. The vicinity of one of the fittings is pressed so as to cause local plastic flow, and the second inner cylindrical part and the outer cylindrical part are coupled by the force of this plastic flow, and the second inner cylindrical part The inner cylindrical part is fixed by the outer cylindrical part and the outer cylindrical part, and a concentric coupling method for precision parts comprising a plurality of members.

Embodiment 2
When incorporating an inner cylindrical part having a through hole larger than the through hole of the outer cylindrical part in the center into an outer cylindrical part with a bottom having a through hole in the center of the inner bottom,
The inner cylindrical part is fitted on the bottom inside the outer cylindrical part while ensuring a clearance between the inner diameter part of the outer cylindrical part and the outer diameter part of the inner cylindrical part. Together
Fitting the second inner cylindrical part to the outer cylindrical part so as to sandwich the inner cylindrical part between the inner bottom of the outer cylindrical part and the second inner cylindrical part;
In this fitted state, a positioning pin having an insertion guide surface formed at the tip is inserted from the through hole of the inner cylindrical part to the through hole of the outer cylindrical part, and the through hole of the inner cylindrical part And concentric provisional positioning with the through hole of the outer cylindrical part,
In the temporary positioning state, the punch is moved and guided along the outer periphery of the positioning pin in the same direction as the insertion direction of the positioning pin, and the second inner cylindrical part and the outer cylindrical part are guided by the punch. The first inner cylinder and the outer cylindrical part are joined by pressing the vicinity of the fitting so that a local plastic flow is generated, and the force of the plastic flow is used to connect the second inner cylindrical part and the outer cylindrical part. A method of concentric coupling of precision parts comprising a plurality of members, wherein the inner cylindrical part is fixed by a cylindrical part and the outer cylindrical part.

Embodiment 3
In any one of Embodiments 1 to 2, the work clamp and the punch are arranged on the outer periphery of the positioning pin concentrically with the positioning pin.
In the temporary positioning state, the positioning pin is operated using a sub-cylinder of a pressure machine,
The punch is moved by the ram of the press machine separately from the positioning pin and the work press while pressing the upper surface of the second inner cylindrical part with the work press. Concentric coupling method for precision parts.

Embodiment 4
A cylindrical nozzle having a fuel injection hole and a swirler having a movable valve, a magnetic circuit for moving the movable valve, a groove for imparting a turning force to fuel, and an inner diameter portion for guiding the movement of the movable valve In the method of assembling the fuel injection valve comprising:
When the swirler is assembled into the nozzle, the clearance is secured between the inner diameter portion of the nozzle and the outer diameter portion of the swirler while the swirler is placed on the bottom inside the nozzle body. And
Furthermore, the upper surface of the swirler is fitted with a plate that has a through hole slightly larger in diameter than the through hole of the swirler and sandwiches the swirler,
In this fitted state, a positioning pin having the same diameter as the inner diameter portion and a centering surface with the fuel injection hole is inserted into the inner diameter portion of the swirler until the tip of the pin comes into contact with the nozzle. The concentric provisional positioning of the inner diameter portion of the swirler and the nozzle,
In the temporary positioning state, the punch is moved and guided along the outer periphery of the positioning pin in the same direction as the insertion direction of the positioning pin, and the fitting portion of the plate and the nozzle is locally moved by the punch. A method of assembling a fuel injection valve, wherein pressing is performed so that plastic flow occurs, and the plate is coupled to the nozzle and the swirler is fixed to the nozzle.

  As described above, according to the present invention, there is no influence of the accuracy of single parts, and the coaxiality after coupling can be maintained.

  The present invention is used in a fuel injection valve for an automobile engine.

FIG. 5 is a longitudinal sectional view showing the steps of the method for connecting the components of the fuel injection valve shown in FIG. 4 according to the first embodiment of the present invention. The longitudinal cross-sectional view of the punch 16 used in the process of the coupling | bonding method of the components of the fuel injection valve shown in FIG. The longitudinal cross-sectional view of the plate 13, the swirler 12, and the nozzle 10 after pressing with the punch 16 shown in FIG. The longitudinal cross-sectional view of the jig | tool and work machine which show the operation | work of the coupling | bonding method of the components shown in FIG. The line graph which compared the coaxiality of a nozzle and a swirler at the time of employ | adopting the coupling | bonding method by 1st Example of this invention, and the coaxiality at the time of employ | adopting the conventional method. The longitudinal cross-sectional view which shows the process of the coupling | bonding method of the components of the fuel injection valve by 2nd Example of this invention. The longitudinal cross-sectional view of a fuel injection valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Nozzle, 10c ... Sheet | seat part, 11 ... Orifice, 12 ... Swirler, 12a, 52a ... Inner diameter part, 13 ... Plate, 14 ... Positioning pin, 14a ... Pin tip, 15 ... Presser,
16 ... Punch, 16a ... Projection, 43 ... Movable valve, 43d ... Ball valve, 51 ... Outer cylindrical part,
51a ... cylindrical hole 52 ... inner cylindrical part 53 ... plate 54 ... positioning pin 54a ... first part 54b ... second part 54c ... pin tip.

Claims (3)

A cylindrical nozzle having a fuel injection hole and a swirler having a movable valve, a magnetic circuit for moving the movable valve, a groove for imparting a turning force to fuel, and an inner diameter portion for guiding the movement of the movable valve In a fuel injection valve consisting of
The swirler, the fuel injection valve characterized that you have been fixed plate coupled to said nozzle by plastic flow by said nozzle. In those described in claim 1, the material of the plate is a fuel injection valve, characterized in that the soft Rakai material than the material of the nozzle. 3. The swirler according to claim 1, wherein the swirler is a material having wear resistance such as a hardened material, a cemented carbide material, a ceramic material, or a surface treatment having wear resistance. A fuel injection valve.

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