JPH10227266A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve for atomizing a fuel favorably. SOLUTION: The side part 12b of a cylinder 12 with a bottom and the outside wall 15a of a valve body 15 are laser welded at a welding position 50 and a plate part 16a provided with an injection hole 16f of an injection hole plate 16 is clamped in an axial direction between a bottom 12a of the cylinder 12 with bottom and a bottom outer wall 15c of the valve body 15. Therefore, an injection direction does not change as the plate part 16a does not expand to an injection side. Further, as the thermal deformation of a valve seat 15b by welding near the valve seat 15b can be prevented, the fuel leak at the closing time of a fuel injection valve can be prevented. Thereby, as the flow of unatomized fuel into a combustion room can be prevented, the generation amount of HC as the not burned component in the fuel can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve, and more particularly to a structure for mounting an injection hole member having an injection hole.

[0002]

2. Description of the Related Art In recent years, due to stricter regulations on exhaust gas from automobiles, atomization of fuel injected from fuel injection valves used in automobile engines is required. In order to promote atomization of fuel, an injection hole member having a thin plate portion is disposed on the fuel downstream side of a valve body having a valve seat, and an injection hole adapted to atomization is provided in the plate portion. Injection valves are known.

[0003] As a structure for attaching an injection hole member to a valve body, there is known a fuel injection valve in which a flat injection hole member is directly welded to a bottom outer wall of the valve body. Further, as shown in U.S. Pat. No. 5,335,864, a perforated plate provided with an injection hole between a valve body and a support plate is sandwiched in the axial direction,
Fuel injection valves are known in which a support plate is welded to a bottom outer wall of a valve body together with a perforated plate.

A fuel injection valve using a nozzle member formed in a cup shape having a nozzle hole as shown in FIGS. 4 and 5 is also known. In the fuel injection valve 100 shown in FIG.
An injection hole member 103 having an injection hole 103a in a valve body 102 having a valve seat 102a on which the needle valve 101 can be seated.
Is mounted on the downstream side of the valve body 102 via the support member 104. The injection hole member 103 has an opening directed toward the non-valve body 102 and a side portion 103b welded to the support member 104. The support member 104 is welded to the outer wall of the valve body 102. The protective cover 105 made of resin is for preventing a metal contact between the stopper provided on the intake pipe and the fuel injection valve 100 when the fuel injection valve 100 is attached to the intake pipe.

[0005] In the fuel injection valve 110 shown in FIG.
After the injection hole member 111 provided with 11a is fitted to the valve body 102, the side portion 111b of the injection hole member 111 and the outer wall of the valve body 102 are directly welded. Resin protective cover 11
Reference numeral 2 is for avoiding metal contact between the fuel injection valve 100 and a stopper provided in the intake pipe.

[0006]

However, in the case where the flat injection hole member as described above is directly welded to the bottom outer wall of the valve body, since the welding portion is close to the valve seat, the valve seat is heated by welding. There is a risk of deformation. Several μm deformation of valve seat
Therefore, when the fuel injection valve in which the valve member is seated on the valve seat is closed, there is a possibility that fuel leaks from a contact portion between the valve member and the valve seat. When the fuel leaks when the fuel injection valve is closed, and this non-atomized leaked fuel flows into the combustion chamber, the concentration of HC as an unburned component discharged into the exhaust gas increases.

The fuel injection valve disclosed in US Pat. No. 5,335,864 also has a welded portion close to a valve seat.
The valve seat may be deformed by the heat during welding. When the valve seat is deformed, fuel may leak when the fuel injection valve is closed as described above. When the leaked fuel that has not been atomized flows into the combustion chamber, the concentration of HC as an unburned component discharged into the exhaust gas increases.

In the case where the cup-shaped injection hole member shown in FIGS. 4 and 5 is attached to the valve body, the welding position between the valve body 102 and the support member 104 or between the valve body 102 and the injection hole member 111 is outside the valve body 102. Because it is a wall,
The distance from the position where the injection hole member is welded to the valve seat 102a becomes longer, and the deformation of the valve seat 102a due to heat can be suppressed. However, the injection hole is formed because the distance from the injection hole to the welding position is farther away. The thin plate portion of the injection hole member swells to the injection side due to the fuel injection pressure, the injection angle changes due to the expansion portion, and the engine becomes wet or the atomization is hindered and the atomization is prevented. Fuel may flow into the combustion chamber. When the fuel that has not been atomized flows into the combustion chamber, the concentration of HC as an unburned component discharged in the exhaust gas increases.

[0009] An object of the present invention is to provide a fuel injection valve capable of favorably atomizing fuel.

[0010]

According to the fuel injection valve of the present invention, the injection hole member provided with the injection hole is sandwiched in the axial direction between the inner member and the outer member. It is possible to prevent the injection hole member from expanding toward the injection side due to the fuel injection pressure. Therefore, since the injection angle is changed by the expansion portion, the inside of the engine can be prevented from being wet due to the change of the injection angle, and the atomization can be prevented from flowing into the combustion chamber without being atomized, so that the HC discharged into the exhaust gas can be prevented. The amount can be reduced. Further, since the outer member has a side portion surrounding the outer wall of the inner member, the inner member and the outer member can be fixed at a position away from the valve seat. Therefore, it is not necessary to fix the inner member and the outer member to the bottom outer wall of the inner member near the valve seat by welding, so that thermal deformation of the valve seat can be prevented. This prevents non-atomized fuel from leaking from the fuel injection valve when the fuel injection valve is closed, so that the amount of HC discharged into exhaust gas can be reduced.

According to the fuel injection valve of the second aspect of the present invention, since the outer wall of the inner member and the side portion of the outer member are welded at a position away from the valve seat, the valve seat is not deformed. The inner member and the outer member can be firmly fixed. According to the fuel injection valve according to the third aspect of the present invention, the inner member and the outer member are deformed by welding the portion where the outer wall of the inner member and the side portion of the outer member are adjacent to each other. It can be firmly fixed without.

According to the fourth aspect of the present invention, since the inner member is press-fitted inside the outer member, the number of steps for welding the outer member and the inner member can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a plurality of examples showing embodiments of the present invention will be described. (First Embodiment) FIGS. 1 and 2 show a fuel injection valve according to a first embodiment of the present invention. As shown in FIG. 2, a valve body 15 as an inner member, a needle valve 20 as a valve member, and a movable core 2 are provided in a bottomed cylindrical member 11 of the fuel injection valve 10.
4, a fixed core 25, a spring 26, an adjusting pipe 27, and a filter 28 are accommodated. An electromagnetic coil 32 wound around a spool 31 around the outer periphery of the cylindrical member 11
The resin mold 40 covers an upper part of the cylindrical member 11 from the electromagnetic coil 32.

The cylindrical member 11 comprises a bottomed cylindrical portion 12 as an outer member, a non-magnetic cylindrical portion 13, and a magnetic cylindrical portion 14.
They are arranged in this order from the lower fuel injection side. The bottomed cylindrical portion 12 includes a bottom portion 12a and side portions 12b.
A through hole 12c is formed at the center of 2a. Through hole 12
The nozzle c communicates with the injection hole 16c formed in the injection hole plate 16 as the injection hole member on the fuel downstream side of the injection hole 16c. The inner diameter of the non-magnetic cylindrical portion 13 is slightly smaller than the inner diameter of the bottomed cylindrical portion 12, and supports the movable core 24 so as to be able to reciprocate.
A fuel inlet 14a is formed on the non-injection side of the magnetic cylinder portion 14, and a filter 28 for removing foreign matter in the fuel is mounted in the fuel inlet 14a.

The valve body 15 is press-fitted into the bottomed cylindrical portion 12, and the injection hole plate 16 is sandwiched between the bottomed cylindrical portion 12 and the valve body 15 in the axial direction. Part 1
An adjacent portion between 2b and the outer wall 15a of the valve body 15 is fixed at a welding position 50 shown in FIG. 1 by laser welding. A valve seat 15b on which the contact portion 21 of the needle valve 20 can be seated is formed on the bottom inner wall of the valve body 15.

The injection hole plate 16 has a plate portion 16a formed in a thin plate shape, and the plate portion 16a is
2 is axially sandwiched between the bottom 12a of the second valve and the bottom outer wall 15c of the valve body 15. An outer peripheral portion 16b of the plate portion 16a is bent toward the valve body 15, and a notch 15 provided on an outer peripheral edge of a bottom outer wall 15c of the valve body 15 is provided.
By fitting the outer peripheral edge 16b to d, the positioning of the injection hole plate 16 can be easily performed. Injection hole 1
6c are formed on the same circumference at the center of the plate portion 16a.

The protective cap 19 made of a resin is
Press-fit. The protection cap 19 is provided for the fuel injection valve 1.
This is for preventing the stopper of the intake pipe from coming into metallic contact with the fuel injection valve 10 when attaching 0 to the intake pipe. As shown in FIG. 2, the needle valve 20 is urged toward the valve seat 15b by the urging force of the spring 26, and the contact portion 21 formed at the tip of the needle valve 20 can be seated on the valve seat 15b. It is. The sliding portion 22 includes the contact portion 2
1 and is reciprocally supported by the inner wall of the valve body 15. The outer wall of the sliding portion 22 is chamfered to form a fuel passage between the outer wall and the inner peripheral wall of the valve body 15.

A joint 23 is formed above the needle valve 20. The joint 23 and the movable core 24 are laser-welded, so that the needle valve 23 and the movable core 24 are joined together.
And reciprocate together. The outer wall of the joint 23 is chamfered to form a fuel passage with the inner peripheral wall of the movable core 24. The fuel flowing from the fuel inlet 14a through the filter 28 passes through the adjusting pipe 27 and the fixed core 25, the gap between the chamfered portion formed at the joint 23 of the needle valve 20 and the inner peripheral wall of the movable core 24, and further,
The needle valve 20 passes through a gap between the circumferential wall of the valve body 15 and the four chamfered portions formed in the sliding portion 22 of the needle valve 20.
Reaches the contact position between the contact portion 21 and the valve seat 15b. When the contact portion 21 is seated on the valve seat 15b, fuel injection from the injection hole 16c is shut off, and when the contact portion 21 is separated from the valve seat 15b, fuel is injected from the injection hole 16c.

The movable core 24 is made of a magnetic material and is formed in a cylindrical shape. The upper end surface of the movable core 24 is
Is provided so as to oppose the lower end surface of the base plate via a predetermined gap. The fixed core 25 is made of a ferromagnetic material, and the adjusting pipe 27 is press-fitted and fixed to the inner wall. By adjusting the amount of press-fit of the adjusting pipe 27, the biasing force of the spring 26 can be adjusted.
The adjusting pipe 27 may be screwed to the fixed core 21.

A spool 31 made of resin is mounted on the outer periphery of the cylindrical member 11, and an electromagnetic coil 32 is wound around the outer periphery of the spool 31. A connector portion 40a is provided so as to protrude from an outer wall of the resin mold 40, and a terminal 41 electrically connected to the electromagnetic coil 32 is embedded in the connector portion 40a.

Next, the operation of the fuel injection valve 10 will be described. (1) When the power supply to the electromagnetic coil 32 is turned off, the needle valve 20 is urged downward in FIG. 1 by the urging force of the spring 26 together with the movable core 24, and the contact portion 21 is seated on the valve seat 15b. Thereby, the fuel injection from the injection hole 16c is shut off. (2) When energization of the electromagnetic coil 32 is turned on, the movable core 2
4 is sucked toward the fixed core 25 against the urging force of the spring 27, so that the needle valve 20 is lifted. As a result, when the contact portion 21 separates from the valve seat 15b, the injection hole 16c
The fuel is injected from.

The plate portion 16a of the injection hole plate 16 includes a bottom portion 12a of the bottomed cylindrical portion 12 and a bottom outer wall 15 of the valve body 15.
Since it is sandwiched in the axial direction at a portion except for the through hole 12c between the plate portion 16c and the plate portion 16c, the plate portion 16a can be prevented from expanding toward the injection side due to the fuel injection pressure. Therefore, plate part 1
By expanding the injection side 6a toward the injection side, the injection angle is changed, so that wetting in the engine is prevented, and the atomization is prevented, so that the fuel that is not atomized can be prevented from flowing into the combustion chamber. Thus, the amount of HC generated as an unburned component in the fuel can be reduced.

Further, the injection hole plate 16 is provided on the valve body 15.
Of the bottomed cylindrical portion 12 and the valve body 1 without directly welding
5 is welded to the outer wall 15b of the bottom outer wall 15b.
valve seat 1 compared to the case where the injection hole plate 16 is directly welded to
The distance from 5b to the welding position 50 increases. Thus, thermal deformation of the valve seat 15b due to welding can be prevented.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. A step-like step 61a is formed on the outer peripheral edge of the inner wall of the bottom portion 61 of the bottomed cylindrical portion 60 as an outer member,
A step 64a that can be fitted to the step 61a is formed on the outer peripheral edge of the bottom outer wall 64 of the valve body 63. Bottomed cylinder 60
Side 62 of the valve body 63 and the outer wall 65 of the valve body 63
Laser welding is performed at a welding position 70 with an injection hole plate 66 serving as an injection hole member sandwiched between the bottom hole 64 and the bottom outer wall 64.

The injection hole plate 66 as an injection hole member has a plate portion 66a formed in a thin plate shape.
6a is axially clamped between the bottom portion 61 of the bottomed cylindrical portion 60 and the bottom outer wall 64 of the valve body 63. Plate part 6
The outer peripheral edge 66b of the nozzle hole 6a is bent so as to fit between the step 61a and the step 64a. Positioning can be easily performed. Four injection holes 66c are formed on the same circumference at the center of the plate portion 66a.

In the above-described embodiments showing the embodiment of the present invention, since the injection hole plate is sandwiched in the axial direction between the bottomed cylindrical portion and the valve body, the injection is performed by the fuel injection pressure. The hole plate can be prevented from expanding toward the injection side.
Therefore, when the injection hole plate expands toward the injection side, the injection angle changes, and wetness in the engine occurs,
Since it is possible to prevent the fuel that has not been atomized due to the atomization from being prevented from flowing into the combustion chamber, it is possible to reduce the amount of HC generated as an unburned component in the fuel.

Further, since the injection hole plate is sandwiched between the bottomed cylindrical portion and the valve body in the axial direction, it is possible to avoid welding and fixing the injection hole plate to the valve body near the valve seat. Therefore, since the deformation of the valve seat due to welding can be prevented, it is possible to prevent the fuel from leaking from the contact portion when the needle valve is seated on the valve seat. This can prevent leaked fuel that has not been atomized from flowing into the combustion chamber, so that the amount of generated HC can be reduced.

In the above embodiments, the bottomed tubular portion and the valve body are fixed by welding the side portion of the bottomed tubular portion to the outer wall of the valve body. Since the valve body receives the force pressed by the cylindrical portion, it is sufficient to simply press-fit the valve body into the bottomed cylindrical portion without welding. In addition, the bottomed cylindrical portion and the valve body are integrally formed to form an inner member,
The injection hole plate may be sandwiched in the axial direction between the bottom outer wall of the inner member and the bottom inner wall of the cup-shaped outer member. The inner and outer members are welded at the sides.

Alternatively, the injection hole member formed in a cup shape may be fitted to the inner member, and the injection hole member may be sandwiched in the axial direction between the inner member and the outer member.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a fuel injection valve according to a first embodiment.

FIG. 3 is a sectional view showing a main part of a fuel injection valve according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a fuel injection valve according to Conventional Example 1.

FIG. 5 is a sectional view showing a main part of a fuel injection valve according to Conventional Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fuel injection valve 11 Cylindrical member 12 Bottom cylinder part (outside member) 12a Side part 12b Bottom part 12c Through hole 15 Valve body (inner member) 15a Outer side wall 15b Valve seat 16 Injection plate (injection member) 16a Plate part 16c Injection hole 20 Needle valve (valve member) 21 Contact part

Claims (4)

[Claims] An injection hole member having an injection hole formed in a thin plate, a reciprocally movable valve member, and a valve seat that opens and closes when the valve member is separated and seated. An inner member provided on the fuel upstream side of the injection hole, a bottom having a through hole communicating with the injection hole on the fuel downstream side of the injection hole, and extending from the bottom to the fuel upstream and surrounding the outer wall of the inner member An outer member having a side portion, wherein the plate portion is sandwiched in the axial direction by the inner member and the outer member. 2. The fuel injection valve according to claim 1, wherein the side portion of the outer member and the outer wall of the inner member are welded. 3. The fuel injection valve according to claim 2, wherein a portion where the side portion and the outer wall are adjacent to each other is welded. 4. The fuel injection valve according to claim 1, wherein the inner member is press-fitted inside the outer member.