JP2012211541A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve that can suppress the thermal deformation of swirl imparting chambers.SOLUTION: The swirl chambers 41 and a center chamber 42 are formed at the side face of one end side of a nozzle plate 8. The center chamber 42 is formed into a bottomed circular recessed shape having an internal side face 42a and a bottom 42b which are almost the same in diameter on the same axial core of a downstream opening 48 of a valve seat member 7. The thickness of a welding point 49 of a member at a side to which heat is input when fixing the nozzle plate 8 to the valve seat member 7 by welding is set thinner than heights of the swirl imparting chambers 46.

Description

  The present invention relates to a fuel injection valve used for fuel injection of an engine.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. In this publication, the passage plate in which the swirl chamber and the side hole are formed, and the injector plate in which the fuel injection hole is formed are overlapped, and heat is applied to the valve seat member in the axial direction to perform welding. Is fixed.

JP 2003-336562 A

In the technique described in Patent Document 1, since the passage plate and the injector plate are overlapped and welded, the thickness of the welded portion is increased and the heat input is increased. Therefore, the swirl chamber (swirling chamber) may be thermally deformed.
The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a fuel injection valve capable of suppressing thermal deformation of the swirl application chamber.

  In order to achieve the above object, in the present invention, when the nozzle plate is fixed to the valve seat member by welding, the thickness of the welded portion of the member that receives heat is made thinner than the height of the swirl application chamber.

  According to the present invention, thermal deformation of the swirl application chamber can be suppressed.

It is an axial sectional view of the fuel injection valve of Example 1. It is an expanded sectional view near the nozzle plate of the fuel injection valve of Example 1. It is the top view which looked at the nozzle plate of Example 1 from the axial direction other end side. It is an expanded sectional view near the nozzle plate of the fuel injection valve of the comparative example. It is the top view which looked at the nozzle plate of the comparative example from the axial direction other end side. It is an expanded sectional view near the nozzle plate of the fuel injection valve of Example 2. It is a figure which shows the external appearance of the valve seat member of Example 2. FIG. FIG. 6 is an enlarged cross-sectional view of the vicinity of a nozzle plate of a fuel injection valve of Example 3. It is a figure which shows the external appearance of the valve seat member of Example 3. FIG. It is the top view which looked at the nozzle plate of the other Example from the axial direction other end side.

[Example 1]
The fuel injection valve 1 according to the first embodiment will be described.
[Configuration of fuel injection valve]
FIG. 1 is an axial sectional view of the fuel injection valve 1. The fuel injection valve 1 is used for an automobile engine or the like.
The fuel injection valve 1 includes a magnetic cylinder 2, a core cylinder 3 accommodated in the magnetic cylinder 2, a valve element 4 slidable in the axial direction, and a valve shaft formed integrally with the valve element 4. 5, a valve seat member 7 having a valve seat 6 that is closed by the valve body 4 when the valve is closed, a nozzle plate 8 having an injection hole through which fuel is injected when the valve is opened, and a direction in which the valve body 4 is opened when energized And an electromagnetic coil 9 to be slid and a yoke 10 for inducing magnetic flux lines.

The magnetic cylinder 2 is made of a metal pipe or the like formed of a magnetic metal material such as electromagnetic stainless steel, and is stepped as shown in FIG. 1 by using means such as deep drawing or pressing or grinding. It is integrally formed in a cylindrical shape. The magnetic cylinder 2 has a large-diameter portion 11 formed on one end side and a small-diameter portion 12 having a smaller diameter than the large-diameter portion 11 and formed on the other end side.
The small diameter portion 12 is formed with a thin portion 13 that is partially thinned. The small-diameter portion 12 includes a core tube housing portion 14 that houses the core tube body 3 on one end side from the thin wall portion 13, and a valve member 15 (valve 4, valve shaft 5, valve seat member on the other end side from the thin wall portion 13. 7) and is divided into a valve member accommodating portion 16 for accommodating. The thin portion 13 is formed so as to surround a gap portion between the core cylinder 3 and the valve shaft 5 in a state where the core cylinder 3 and the valve shaft 5 described later are accommodated in the magnetic cylinder 2. The thin wall portion 13 increases the magnetic resistance between the core tube housing portion 14 and the valve member housing portion 16, and magnetically blocks between the core tube housing portion 14 and the valve member housing portion 16.

The inner diameter of the large-diameter portion 11 constitutes a fuel passage 17 for sending fuel to the valve member 15, and a fuel filter 18 for filtering the fuel is provided at one end of the large-diameter portion 11. A pump 47 is connected to the fuel passage 17. The pump 47 is controlled by a pump control device 54.
The core cylinder 3 is formed in a cylindrical shape having a hollow portion 19 and is press-fitted into the core cylinder housing portion 14 of the magnetic cylinder 2. The hollow portion 19 accommodates a spring receiver 20 fixed by means such as press fitting. A fuel passage 43 penetrating in the axial direction is formed at the center of the spring receiver 20.
The outer shape of the valve body 4 is formed in a substantially spherical shape, and has a fuel passage surface 21 cut in parallel with the axial direction of the fuel injection valve 1 on the circumference. The valve shaft 5 has a large-diameter portion 22 and a small-diameter portion 23 whose outer shape is smaller than the large-diameter portion 22.

The valve body 4 is integrally fixed to the tip of the small diameter portion 23 by welding. In addition, the black semicircle and black triangle in a figure have shown the welding location. A spring insertion hole 24 is formed at the end of the large diameter portion 22. A spring seat 25 having a smaller diameter than the spring insertion hole 24 is formed at the bottom of the spring insertion hole 24, and a stepped spring receiving portion 26 is formed. A fuel passage hole 27 is formed at the end of the small diameter portion 23. The fuel passage hole 27 communicates with the spring insertion hole 24. A fuel outflow hole 28 penetrating the outer periphery of the small diameter portion 23 and the fuel passage hole 27 is formed.
The valve seat member 7 includes a substantially conical valve seat 6, a valve body holding hole 30 formed on the one end side from the valve seat 6 so as to be substantially the same as the diameter of the valve body 4, and one end opening side from the valve body holding hole 30. An upstream opening 31 having a larger diameter and a downstream opening 48 that opens to the other end of the valve seat 6 are formed.

The valve shaft 5 and the valve body 4 are accommodated in the magnetic cylinder 2 so as to be slidable in the axial direction. A coil spring 29 is provided between the spring receiver 26 and the spring receiver 20 of the valve shaft 5 to urge the valve shaft 5 and the valve body 4 to the other end side. The valve seat member 7 is inserted into the magnetic cylinder 2 and fixed to the magnetic cylinder 2 by welding. The valve seat 6 is formed so that the diameter decreases from the valve body holding hole 30 toward the downstream opening 48 at an angle of 45 °, and the valve body 4 is seated on the valve seat 6 when the valve is closed.
An electromagnetic coil 9 is inserted into the outer periphery of the core cylinder 3 of the magnetic cylinder 2. That is, the electromagnetic coil 9 is disposed on the outer periphery of the core cylinder 3. The electromagnetic coil 9 includes a bobbin 32 formed of a resin material and a coil 33 wound around the bobbin 32. The coil 33 is connected to the electromagnetic coil control device 55 via the connector pin 34.
The electromagnetic coil control device 55 energizes the coil 33 of the electromagnetic coil 9 to energize the fuel injection valve 1 in accordance with the timing of injecting fuel into the combustion chamber calculated based on the information from the crank angle sensor that detects the crank angle. Open the valve.

The yoke 10 has a hollow through-hole, and has a large-diameter portion 35 formed on one end opening side, a medium-diameter portion 36 formed with a smaller diameter than the large-diameter portion 35, and a diameter smaller than the medium-diameter portion 36. It is composed of a small diameter portion 37 formed on the end opening side. The small diameter portion 37 is fitted on the outer periphery of the valve member housing portion 16. An electromagnetic coil 9 is accommodated on the inner periphery of the medium diameter portion 36. A connecting core 38 is disposed on the inner periphery of the large diameter portion 35.
The connecting core 38 is formed in a substantially C shape by a magnetic metal material or the like. The yoke 10 is connected to the magnetic cylinder 2 at the large-diameter portion 35 via the small-diameter portion 37 and the connecting core 38, that is, magnetically connected to the magnetic cylinder 2 at both ends of the electromagnetic coil 9. It becomes. A protector 52 for holding the O-ring 40 for connecting the fuel injection valve 1 to the intake port of the engine and protecting the tip of the magnetic cylinder is attached to the tip of the yoke 10 on the other end side.

When power is supplied to the electromagnetic coil 9 through the connector pin 34, a magnetic field is generated, and the valve body 4 and the valve shaft 5 are opened against the biasing force of the coil spring 29 by the magnetic force of the magnetic field.
As shown in FIG. 1 of the fuel injection valve 1, most of the fuel injection valve 1 is covered with a resin cover 53. The portion covered with the resin cover 53 is from the portion excluding one end portion of the large-diameter portion 11 of the magnetic cylindrical body 2 to the electromagnetic coil 9 installation position of the small-diameter portion 12 to the medium-diameter portion 36 of the electromagnetic coil 9 and the yoke 10. Between the outer periphery of the connecting core 38 and the large-diameter portion 35, the outer periphery of the large-diameter portion 35, the outer periphery of the medium-diameter portion 36, and the outer periphery of the connector pin 34. The tip of the connector pin 34 is formed by opening a resin cover 53 so that the connector of the control unit can be inserted.
An O-ring 39 is provided on the outer periphery of one end of the magnetic cylinder 2, and an O-ring 40 is provided on the outer periphery of the small diameter portion 37 of the yoke 10.
A nozzle plate 8 is welded to the other end side of the valve seat member 7. The nozzle plate 8 is injected with a plurality of swirl chambers 41 that give a swirl (swirl flow) to the fuel, a central chamber 42 that distributes the fuel to each swirl chamber 41, and a fuel that has been swirled in the swirl chamber 41. An injection hole 44 is formed.

[Configuration of nozzle plate]
FIG. 2 is an enlarged cross-sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1. FIG. 3 is a plan view of the nozzle plate 8 as viewed from the other axial end side (downstream side). The cross section of the nozzle plate 8 in FIG. 2 is a cross section cut at the position of the straight line AA in FIG. In FIG. 3, a swirl chamber 41 and a central chamber 42 formed on one end side in the axial direction of the nozzle plate 8 are indicated by dotted lines. Moreover, the hatching part of FIG. 3 shows a welding location, and the area is S1. The configuration of the nozzle plate 8 will be described with reference to FIGS.

A swirl chamber 41 and a central chamber 42 are formed on one side surface of the nozzle plate 8. The central chamber 42 is formed in a bottomed circular concave shape having an inner side surface 42a and a bottom portion 42b having substantially the same diameter on the same axis as the axis of the downstream opening 48 of the valve seat member 7.
Four swirl chambers 41 are formed, each including a communication path 45 and a swirl imparting chamber 46. The communication passage 45 is formed to extend in the radial direction of the central chamber 42. A swirl application chamber 46 is formed at the tip of the communication path 45, and the communication path 45 is connected in the tangential direction of the swirl application chamber 46. The swirl imparting chamber 46 is formed in a bottomed circular concave shape having an inner side surface 46a and a bottom 46b, and the bottom 46b is formed with an injection hole 44 which is a cylindrical through hole concentric with the swirl imparting chamber 46. Has been.
On the other end side of the nozzle plate 8, a weld 49 is formed by cutting out the edge of the disk over the entire circumference. The thickness of the welded portion 49 is formed thinner than the height of a swirl application chamber 46 described later. Further, the thickness of the welded portion 49 (B in FIG. 2) is formed to be thicker than the thickness (C in FIG. 2) of the thinnest portion of the swirl application chamber 46 in the radially outer direction.
When the nozzle plate 8 is fixed to the valve seat member 7, heat is input from the welded portion 49 toward the valve seat member 7 in the axial direction (arrow X1 direction in FIG. 2), and welding is performed over the entire circumference.

[Action]
(Fuel flow when the valve is closed)
When the coil 33 of the electromagnetic coil 9 is not energized, the valve shaft 5 is biased to the other end side by the coil spring 29 so that the valve body 4 is seated on the valve seat 6. For this reason, the space between the valve body 4 and the valve seat 6 is closed, so that fuel is not supplied to the nozzle plate 8 side.
(Fuel flow when the valve opens)
When the coil 33 of the electromagnetic coil 9 is energized, the valve shaft 5 is pulled up to one end side by the electromagnetic force against the urging force of the coil spring 29. Therefore, the space between the valve body 4 and the valve seat 6 is released, and fuel is supplied to the nozzle plate 8 side.
The fuel supplied to the nozzle plate 8 first enters the central chamber 42, collides with the bottom 42 b of the central chamber 42, thereby converting the axial flow into the radial flow and flows into each communication passage 45. Since the communication path 45 is connected in the tangential direction of the swirl application chamber 46, the fuel that has passed through the communication path 45 swirls along the inner surface 46 a of the swirl application chamber 46. A swirl force (swirl force) is applied to the fuel in the swirl imparting chamber 46, and the fuel having the swirl force is injected while swirling along the side wall portion of the injection hole 44. Therefore, the fuel spray immediately after being injected from the injection hole 44 spreads conically in a thin liquid film state by the edge portion of the opening of the injection hole 44. Thereafter, the fuel in the liquid film state is separated into droplets that are atomized. As a result, fuel vaporization can be promoted, and in particular, generation of nitrogen oxides and the like during low temperature starting can be reduced.

(Controlling thermal deformation of swirl chamber)
4 and 5 are diagrams showing a welding area when the thickness of the nozzle plate 8 is formed to be constant. FIG. 4 is an enlarged sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1. FIG. 5 is a plan view of the nozzle plate 8 viewed from the other axial end side (downstream side). In FIG. 5, a swirl chamber 41 and a central chamber 42 formed on one end side in the axial direction of the nozzle plate 8 are indicated by dotted lines. Further, the hatched portion in FIG. 5 is a welded portion, and its area S2 (S2> S1).
Since the swirl imparting chamber 46 and the injection hole 44 are arranged in the axial direction in the nozzle plate 8 of the first embodiment, when the nozzle plate 8 is formed to have a constant thickness as shown in FIG. The thickness of 8 becomes thicker. Therefore, when the nozzle plate 8 is welded to the valve seat member 7, the amount of heat input increases, and the welding area S2 increases as shown in FIG. Therefore, there is a possibility that heat is transferred to the swirl application chamber 46 during welding and is deformed.
In consideration of the above problems, it is conceivable to reduce the thickness of each plate by forming the injection holes 44 in different plates. However, since it is necessary to weld the plates in piles, the amount of heat input increases and the welding area increases. For this reason, heat transfer to the swirl chamber 46 could not be suppressed.

It is also conceivable to reduce the height of the swirl chamber 46. However, since it is necessary to secure the fuel injection amount, it is necessary to secure the volume of the swirl imparting chamber 46. Therefore, it is necessary to increase the area of the swirl imparting chamber 46 by the amount that the swirl imparting chamber 46 is lowered. The area of the nozzle plate 8 itself is determined in relation to other members, that is, increasing the area of the swirl application chamber 46 will cause the swirl application chamber 46 to approach the welding location, so the swirl application chamber 46 This will increase the heat transfer to 46.
As described above, the fuel spray immediately after being injected from the injection hole 44 spreads conically in a thin liquid film state by the edge portion of the opening of the injection hole 44. Therefore, the height of the injection hole 44 is not so necessary. That is, the height of the nozzle plate 8 is affected by the height of the swirl application chamber 46 rather than the height of the injection hole 44.
Therefore, in the fuel injection valve 1 according to the first embodiment, the thickness (a in FIG. 2) of the welded portion 49 of the nozzle plate 8 which is a member that receives heat when the nozzle plate 8 is fixed by welding is swirled. The chamber 46 was formed thinner than the height (b in FIG. 2).
Thereby, since the thickness of the welded portion 49 of the nozzle plate 8 can be reduced, the amount of heat input can be reduced, and the welding area can be reduced. Therefore, heat transfer to the swirl application chamber 46 can be suppressed, and deformation of the swirl application chamber 46 can be suppressed.

(Ensuring the strength of the nozzle plate)
In the fuel injection valve 1 according to the first embodiment, the fuel that has flowed from the downstream opening 48 of the valve seat member 7 collides with the bottom 42 b of the central chamber 42 of the nozzle plate 8. Therefore, a force acts on the nozzle plate 8 on the other end side in the axial direction (in the direction of arrow X2 in FIG. 2). The nozzle plate 8 is supported by this force at the welded portion of the welded portion 49, and bending stress (F1 in FIG. 2) acts on the periphery thereof. Further, the thinnest part of the portion where the axial force (in the direction of arrow X2 in FIG. 2) acts on the nozzle plate 8 is the thinnest part (C portion in FIG. 2) in the radially outward direction of the swirling chamber 46. Here, a shearing force (F2 in FIG. 2) acts.
In the fuel injection valve 1 of the first embodiment, the thickness of the welded portion 49 is formed to be thicker than that of the thinnest portion (C portion in FIG. 2) of the radially outer wall of the swirl application chamber 46. Welding was performed by inputting heat in the axial direction to the valve seat member 7 side.
The nozzle plate 8 is made of a uniform material. In this case, generally, the breaking strength of the material is higher with respect to the shearing force than to the bending stress. By forming the welded portion 49 to be thicker than the thinnest portion of the radially outer wall of the swirl application chamber 46, the support strength of the nozzle plate 8 with respect to the valve seat member 7 can be ensured.
The heat input direction can be a radial direction toward the boundary between the nozzle plate 8 and the valve seat member 7, but the direction in which the nozzle plate 8 and the valve seat member 7 are separated during welding (in the direction of arrow X3 in FIG. 4). The force acts on. In the fuel injection valve 1 according to the first embodiment, welding is performed by inputting heat in the axial direction from the nozzle plate 8 to the valve seat member 7 side, so that the nozzle plate 8 and the valve seat member 7 are separated from each other during welding. It is difficult for the force to act, and the liquid tightness between the nozzle plate 8 and the valve seat member 7 can be secured.

[effect]
The effects of the fuel injection valve 1 of the first embodiment are listed below.
(1) A valve body 4 provided slidably, a valve seat 6 on which the valve body 4 sits when the valve is closed, and a valve seat member 7 having a downstream opening 48 on the downstream side, and a valve seat member A nozzle plate 8 fixed by welding, the nozzle plate 8 communicates with the downstream opening 48 of the valve seat member 7, and has a central chamber 42 having a cylindrical inner surface 42a, and more than the central chamber 42. A swirl imparting chamber 46 formed on the downstream side and having a cylindrical inner side surface 46a, which swirls fuel inside to impart a turning force, and a cylindrical portion formed at the bottom 46b of the swirl imparting chamber 46 and penetrates to the outside. In the fuel injection valve having the communication hole 45 connected to the swirl application chamber 46 and the central chamber 42 while being connected to the swirl application chamber 46 in the tangential direction of the swirl application chamber 46 and the injection hole 44 When fixing 8 by welding, the thickness of the welded part 49 on the heat input side It was thinner than the height of the Le imparting chamber 46.
Therefore, since the thickness of the welded portion 49 of the nozzle plate 8 can be reduced, the amount of heat input can be reduced, and the welding area can be reduced. Therefore, heat transfer to the swirl application chamber 46 can be suppressed, and deformation of the swirl application chamber 46 can be suppressed.

(2) The member on the heat input side is the nozzle plate 8, and the welded portion 49 is formed by cutting out the edge of the disk-shaped member over the entire circumference, and the thickness of the welded portion 49 is set to the swirl chamber 46. It was formed thicker than the thinnest part of the radially outer wall, and welding was performed by inputting heat in the axial direction from the nozzle plate 8 to the valve seat member 7 side.
Therefore, the support strength of the nozzle plate 8 with respect to the valve seat member 7 can be ensured. Further, it is difficult for a force to act in the direction in which the nozzle plate 8 and the valve seat member 7 are separated during welding, and liquid tightness between the nozzle plate 8 and the valve seat member 7 can be secured.

[Example 2]
The fuel injection valve 1 according to the second embodiment will be described. In the fuel injection valve 1 of the first embodiment, a welded portion 49 is formed on the nozzle plate 8 and heat is input from the nozzle plate 8 side during welding. In the fuel injection valve 1 of the second embodiment, the welded portion is attached to the valve seat member 7. 50 was formed, and heat was input from the valve seat member 7 during welding. In the following description, the same components as those of the fuel injection valve 1 of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

[Configuration of valve seat member]
FIG. 6 is an enlarged sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1. FIG. 7 is a view showing an appearance of the valve seat member 7 after the nozzle plate 8 is welded to the valve seat member 7. A hatched portion in FIG. 7 indicates a welded portion. The configuration of the valve seat member 7 will be described with reference to FIGS.
As shown in FIG. 6, a welded portion 50 extending in the axial direction is formed at the other end portion of the valve seat member 7. The thickness a of the weld 50 is formed thinner than the height b of the swirl chamber 46. A substantially cylindrical hollow portion 50a is formed on the inner peripheral side of the welded portion 50. The nozzle plate 8 is accommodated in the hollow portion 50a. Unlike the first embodiment, the nozzle plate 8 has a uniform axial thickness.
When the nozzle plate 8 is fixed to the valve seat member 7, heat is input in the radial direction from the welded portion 50 of the valve seat member 7 toward the nozzle plate 8, and welding is performed over the entire circumference as shown in FIG. ing.

[Action]
(Controlling thermal deformation of swirl chamber)
As described with reference to FIGS. 4 and 5 in the first embodiment, since the swirl application chamber 46 and the injection hole 44 are aligned in the axial direction, the axial thickness of the nozzle plate 8 is increased. For this reason, when heat is input in the axial direction and welding is performed, the amount of heat input increases and the welding area increases, and heat may be transferred to the swirl application chamber 46 during welding to cause deformation.
Therefore, in the fuel injection valve 1 of the second embodiment, as shown in FIG. 6, the thickness a of the welded portion 50 of the valve seat member 7 which is a member on the heat input side when the nozzle plate 8 is fixed by welding, The swirl chamber 46 is formed thinner than the height b.
Thereby, since the thickness a of the welded portion 50 of the nozzle plate 8 can be reduced, the amount of heat input can be reduced, and the welding area can be reduced. Therefore, heat transfer to the swirl application chamber 46 can be suppressed, and deformation of the swirl application chamber 46 can be suppressed.

Further, in the fuel injection valve 1 of Example 2, the welded portion 50 is extended in the axial direction, and welding is performed by heat input from the welded portion 50 in the radial direction.
As a result, the portion having the largest welding area can be the radially outer side surface far from the swirl application chamber 46, so that heat transfer to the swirl application chamber 46 during welding is suppressed, and thermal deformation of the swirl application chamber 46 is suppressed. Can be suppressed.
Further, in the fuel injection valve 1 of the second embodiment, the member on the heat input side is the valve seat member 7, the welded portion 50 has a substantially cylindrical hollow portion 50a on the inner peripheral side, and the nozzle plate 8 is disposed in the hollow portion. It was accommodated in 50a, and welding was performed by inputting heat from the welded portion 50 to the nozzle plate 8 from the radial direction.
As a result, the portion having the largest welding area can be used as the side surface of the valve seat member 7 far from the swirl application chamber 46, so that heat is prevented from being transmitted to the swirl application chamber 46 during welding. Thermal deformation can be suppressed.

[effect]
(3) The weld 50 is extended in the axial direction, and welding is performed by heat input from the weld 50 in the radial direction.
Therefore, the portion having the largest welding area can be a radially outer side surface far from the swirl application chamber 46, so that heat transfer to the swirl application chamber 46 during welding is suppressed, and thermal deformation of the swirl application chamber 46 is suppressed. Can be suppressed.
(4) The member on the heat input side is the valve seat member 7, the welded portion 50 has a substantially cylindrical hollow portion 50a on the inner peripheral side, the nozzle plate 8 is accommodated in the hollow portion 50a, and the welded portion 50 The nozzle plate 8 was welded by heat input from the radial direction.
Therefore, since the portion with the largest welding area can be the side surface of the valve seat member 7 far from the swirl application chamber 46, heat transfer to the swirl application chamber 46 during welding is suppressed, and the swirl application chamber 46 Thermal deformation can be suppressed.

Example 3
A fuel injection valve 1 of Embodiment 3 will be described. In the fuel injection valve 1 of the second embodiment, the welded portion 50 is formed on the valve seat member 7 and heat is input from the valve seat member 7 during welding. However, in the fuel injection valve 1 of the third embodiment, the nozzle plate 8 A welded portion 51 is formed on the nozzle plate and heat is input from the nozzle plate 8 during welding. In the following description, the same components as those of the fuel injection valve 1 of the first embodiment and the second embodiment are denoted by the same reference numerals and the description thereof is omitted.

[Configuration of nozzle]
FIG. 8 is an enlarged cross-sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1. FIG. 9 is a view showing the appearance of the valve seat member 7 after the nozzle plate 8 is welded to the valve seat member 7. A hatched portion in FIG. 9 indicates a welded portion. The configuration of the nozzle plate 8 will be described with reference to FIGS.
As shown in FIG. 8, a welded portion 51 extending in the axial direction is formed on one end side of the nozzle plate 8. The thickness a of the weld 51 is formed to be thinner than the height b of the swirl chamber 46. A substantially cylindrical hollow portion 51 a is formed on the inner peripheral side of the welded portion 51. A small diameter portion 7a is formed by cutting out the outer periphery of the other end portion of the valve seat member 7. The outer diameter of the small diameter portion 7a is slightly smaller than the inner diameter of the hollow portion 51a, and the small diameter portion 7a is accommodated in the hollow portion 51a.
When fixing the nozzle plate 8 to the valve seat member 7, heat is input in the radial direction from the welded portion 51 of the nozzle plate 8 toward the valve seat member 7, and welding is performed over the entire circumference as shown in FIG. ing.

[Action]
(Controlling thermal deformation of swirl chamber)
As described with reference to FIGS. 4 and 5 in the first embodiment, since the swirl application chamber 46 and the injection hole 44 are aligned in the axial direction, the axial thickness of the nozzle plate 8 is increased. For this reason, when heat is input in the axial direction and welding is performed, the amount of heat input increases and the welding area increases, and heat may be transferred to the swirl application chamber 46 during welding to cause deformation.
Therefore, in the fuel injection valve 1 according to the third embodiment, the thickness of the welded portion 51 of the nozzle plate 8 which is a member that receives heat when the nozzle plate 8 is fixed by welding is set to be larger than the height of the swirl application chamber 46. Thinly formed.
Thereby, since the thickness of the welded portion 51 of the nozzle plate 8 can be reduced, the amount of heat input can be reduced, and the welding area can be reduced. Therefore, heat transfer to the swirl application chamber 46 can be suppressed, and deformation of the swirl application chamber 46 can be suppressed.

Further, in the fuel injection valve 1 of Example 3, the welded portion 51 is extended in the axial direction, and welding is performed by heat input from the welded portion 51 in the radial direction.
As a result, the portion having the largest welding area can be the radially outer side surface far from the swirl application chamber 46, so that heat transfer to the swirl application chamber 46 during welding is suppressed, and thermal deformation of the swirl application chamber 46 is suppressed. Can be suppressed.
Further, in the fuel injection valve 1 of the third embodiment, the member on the heat input side is the nozzle plate 8, the welded portion 51 has a substantially cylindrical hollow portion 51 a on the inner peripheral side, and the small diameter portion of the valve seat member 7. 7a is accommodated in the hollow portion 51a, and welding is performed by inputting heat from the welding portion 51 to the valve seat member 7 from the radial direction.
As a result, the portion with the largest welding area can be used as the side surface of the welded portion 51 extending from the nozzle plate 8, so that heat is prevented from being transferred to the swirl application chamber 46 during welding. Thermal deformation can be suppressed.

[effect]
(5) The member on the heat input side is the nozzle plate 8, the welded part 51 has a substantially cylindrical hollow part 51 a on the inner peripheral side, the valve seat member 7 is accommodated in the hollow part 51 a, and the welded part 51 Therefore, the valve seat member 7 is welded by heat input from the radial direction.
Therefore, since the portion having the largest welding area can be used as the side surface of the welded portion 51 extending from the nozzle plate 8, it is possible to prevent heat from being transferred to the swirl application chamber 46 during welding. Thermal deformation can be suppressed.

[Other Examples]
As mentioned above, although this invention has been demonstrated based on Example 1 thru | or Example 3, the concrete structure of invention is not limited to each Example, The design change etc. of the range which does not deviate from the summary of invention are carried out. Even if it exists, it is included in this invention.
In the fuel injection valve 1 of the first to third embodiments, four swirl chambers 41 are formed. However, the number of the swirl chambers 41 may be changed as appropriate according to the design of the fuel injection amount.
In the fuel injection valve 1 of the first to third embodiments, the injection hole 44 is formed concentrically with the inner surface 46a of the swirl application chamber 46. However, the injection hole 44 is different if it is the bottom of the swirl application chamber 46. You may arrange in a position.
In the fuel injection valve 1 of the first to third embodiments, the swirl chamber 46 is formed in a circular concave shape, but the outer peripheral shape may be a spiral shape, an involute curve shape, or the like.
In the fuel injection valve 1 of the first to third embodiments, the central chamber 42 is provided in the nozzle plate 8, but the central chamber 42 may not be provided.
FIG. 10 is a plan view of the nozzle plate 8 viewed from the other axial end side (downstream side). As shown in FIG. 10, the communication paths 45 may be directly connected without providing the central chamber 42.

1 Fuel injection valve
4 Disc
6 Valve seat
7 Valve seat member
8 Nozzle plate
41 Swirl room
42 Central room
42a Inside surface
42b bottom
46 Swirl grant room
46a inner surface
46b bottom
48 Downstream opening (opening)
49 Weld
50 welds
50a Hollow part
51 welds
51a Hollow part

Claims (5)

A valve body slidably provided;
A valve seat on which the valve body sits when the valve is closed, and a valve seat member having an opening on the downstream side;
A nozzle plate fixed to the valve seat member by welding;
With
The nozzle plate is
A swirl application chamber that is formed on the downstream side of the valve seat member, has a cylindrical or spiral inner surface, and applies a turning force by turning fuel inside.
An injection hole formed in a cylindrical shape at the bottom of the swirl application chamber and penetrating to the outside;
A communication path that is connected to the swirl application chamber toward the tangential direction of the swirl application chamber and intersects near the center of the nozzle plate;
In a fuel injection valve having
The fuel injection valve according to claim 1, wherein a thickness of a welded portion of a member that inputs heat when the nozzle plate is fixed by welding is made thinner than a height of the swirl application chamber. The fuel injection valve according to claim 1, wherein
The member on the heat input side is the nozzle plate, and the welded portion is formed by cutting out the edge of the disk-shaped member over the entire circumference.
Forming the thickness of the welded portion thicker than the thinnest portion of the radially outer wall of the swirl application chamber;
A fuel injection valve, wherein welding is performed by heat input in an axial direction from the nozzle plate toward the valve seat member. The fuel injection valve according to claim 1, wherein
Extending the weld in the axial direction;
A fuel injection valve, wherein welding is performed by heat input in a radial direction from the weld. The fuel injection valve according to claim 3,
The heat input side member is the valve seat member, and the welded portion has a substantially cylindrical hollow portion on the inner peripheral side,
A fuel injection valve, wherein the nozzle plate is accommodated in the hollow portion, and welding is performed by heat input from the welded portion to the nozzle plate in a radial direction. The fuel injection valve according to claim 3,
The member on the heat input side is the nozzle plate, and the welded portion has a substantially cylindrical hollow portion on the inner peripheral side,
An end portion of the valve seat member is accommodated in the hollow portion, and heat is applied from the welded portion to the nozzle plate in a radial direction to perform welding.

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