JP4123180B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve that injects fuel into an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”).

Conventionally, as a configuration for intermittently injecting fuel from an injection hole and supporting a movable member sucked to the fixed core side, a configuration is known in which the movable member is supported at two or more locations separated in the reciprocating direction ( For example, see Patent Document 1).
Further, a configuration is known in which the movable member is supported at one place in the reciprocating direction, and the plane of the movable member is seated on a flat valve seat (for example, see Patent Document 2).

Japanese Patent No. 3439943 US Pat. No. 5,692,723

However, in the configuration in which the movable member is supported at two or more locations separated in the reciprocating direction, the support member supports the movable member so that the movable member can be smoothly reciprocated, and is supported in order to align the centers of the movable member and the support member. It is necessary to process the member with high accuracy. Therefore, manufacture is difficult and manufacturing cost increases.
In contrast, in the configuration in which the movable member and the valve seat are in contact with each other, the movable member can be reliably seated on the valve seat even if the seating position of the movable member seated on the valve seat is shifted by the clearance of the support location. It is not necessary to process the supporting part with high accuracy. However, the plane of the movable member may be inclined with respect to the flat valve seat due to the clearance of the support portion. As a result, the posture of the movable member seated on the flat valve seat is not stable, and there is a possibility that the fuel injection amount varies and the valve sealing deteriorates.
The present invention has been made to solve the above problems, and provides a fuel injection valve that reduces the displacement of the seating position of the movable member seated on the valve seat in a configuration in which the movable member seats on the conical valve seat. The purpose is to do.

According to the first to fourth aspects of the present invention, the valve member for intermittently injecting fuel from the nozzle hole is seated on a conical valve seat whose diameter is reduced toward the nozzle hole, and the movable member is biased toward the valve seat. The engaging portion of the movable member that engages the urging member is substantially the same as the center of gravity of the movable member, or is located on the valve seat side with respect to the center of gravity. That is, the force point of the urging force that the urging member urges the movable member toward the valve seat is located substantially on the same side as the center of gravity of the movable member. Further, the movable member is supported only by the support member in the reciprocating direction when the movable member is separated from the valve seat, and is supported by only one portion of the support member. According to this configuration, since the axial displacement and inclination of the movable member when moving toward the valve seat due to the urging force of the urging member can be reduced, it is possible to prevent variations in the fuel injection amount and deterioration of valve tightness after the operation is stopped. . Further, the shift of the seating position of the movable member seated on the valve seat can be reduced without processing the support portion where the support member supports the movable member with high accuracy. Therefore, it is easy to process the support member that supports the movable member.
Further, since the valve seat is formed in a conical shape whose diameter is reduced toward the nozzle hole side, the valve member is guided to the conical surface even when the position where the valve member is seated on the valve seat is deviated from the center of the valve seat. As a result, the centers of the valve member and the valve seat coincide.

  According to the second aspect of the present invention, the locking portion of the movable member that locks the urging member is located closer to the valve seat than the support location where the movable member is supported by the support member. That is, the force point of the urging force that the urging member urges the movable member toward the valve seat is located closer to the valve seat than the fulcrum where the movable member is supported by the support member. Therefore, the axial deviation and inclination of the movable member when moving toward the valve seat by the urging force of the urging member can be reduced. According to this structure, the shift | offset | difference of the seating position of the movable member seated on a valve seat can be reduced, without processing the support location where a support member supports a movable member with high precision. Therefore, it is easy to process the support member that supports the movable member.

Further, as in the first to fourth aspects of the present invention, even if the support member supports the movable member at one location in the reciprocating direction, the displacement of the seating position of the movable member seated on the valve seat can be reduced. . Therefore, the support member can be easily processed.
Furthermore, in the invention 4 according to claims 1, movable member when said movable member moves away from the valve seat, it is supported only by the support member in the reciprocating direction, and, being supported only in one place of the support member because there, when the valve member is shifted from the center position the valve seat for the valve seat, by the valve member is guided along the conical surface of the valve seat, readily modify the deviation of the seating position of the valve seat it can.

Here, when the sliding clearance δ of the supporting portion where the supporting member supports the movable member at one location in the reciprocating direction is set to δ <10 μm, the sliding resistance of the movable member increases, and the movable member smoothly reciprocates. Is disturbed. Further, if δ> 150 μm, the displacement width of the movable member due to the sliding clearance becomes large, so that the position of the movable member seated on the valve seat may vary. Therefore, in the invention described in claim 4 , the sliding clearance δ between the movable member and the support member is set to 10 μm ≦ δ ≦ 150 μm. Thereby, while a movable member can reciprocate smoothly, the dispersion | variation in the seating position of the movable member seated on a valve seat can be reduced.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The fuel injection valve according to the first embodiment of the present invention is shown in FIG. The fuel injection valve 10 according to the first embodiment is installed in, for example, an intake pipe connected to a combustion chamber of an engine of a gasoline engine, and injects fuel into intake air flowing through an intake passage formed by the intake pipe. The fuel injection valve 10 may be applied to a direct injection type gasoline engine that directly injects fuel into a combustion chamber of a gasoline engine, or may be applied to a diesel engine.

  The pipe member 12 of the fuel injection valve 10 has a magnetic pipe 13 and a nonmagnetic pipe 14 in this order from the nozzle hole plate 18 side where the nozzle holes 18a are formed. A nonmagnetic pipe 14 is fitted over the outer peripheral side of the magnetic pipe 13 in the axial direction. The overlapping part of the magnetic pipe 13 and the nonmagnetic pipe 14 is coupled by welding or the like. The magnetic pipe 13 and the nonmagnetic pipe 14 are integrally formed without having a seam from one end in the axial direction to the other end.

  The magnetic pipe 13 as a support member accommodates the valve body 16 on the inner peripheral wall of the end opposite to the nonmagnetic pipe 14 and is fixed to the valve body 16 by welding or the like. The valve body 16 as the valve seat member forms a valve seat 17 on the inner peripheral wall on which the contact portion 23 of the valve member 22 can be seated. The valve seat 17 is a conical surface that decreases in diameter toward the nozzle hole 18a. A nozzle hole plate 18 is joined to the bottom outer wall of the valve body 16 by welding or the like. The nozzle hole plate 18 is formed with one or a plurality of nozzle holes 18a for injecting fuel.

  The nonmagnetic pipe 14 covers the outer periphery of the gap 110 formed between the movable core 26 and the fixed core 30. The nonmagnetic pipe 14 extends to the end of the fuel injection valve 10 opposite to the injection hole plate 18 and forms a fuel inlet 15. A fuel filter 60 is installed on the inner peripheral wall of the nonmagnetic pipe 14 on the fuel inlet 15 side. The fuel filter 60 removes foreign matters contained in the fuel flowing into the fuel passage 100 from the fuel inlet 15. An O-ring 54 as a seal member is fitted to the outer peripheral wall of the nonmagnetic pipe 14 on the fuel inlet 15 side. The open end of the nonmagnetic pipe 14 forming the fuel inlet 15 is bent radially outward to prevent the O-ring 54 from falling off the nonmagnetic pipe 14.

  The movable member 20 has a valve member 22 and a movable core 26. Reference numeral 200 shown in FIG. 1 is the center of gravity of the movable member 20. The valve member 22 is a bottomed cylindrical hollow and has a contact portion 23 that can be seated on a valve seat 17 formed in the valve body 16. One or more fuel holes 22 a penetrating the side wall of the valve member 22 are formed on the upstream side of the contact portion 23. The fuel that has flowed into the valve member 22 passes through the fuel hole 22a from the inside to the outside and travels toward the valve portion formed by the contact portion 23 and the valve seat 17. A clearance 102 larger than the sliding clearance is formed between the outer peripheral wall of the valve member 22 and the inner peripheral wall of the valve body 16.

  The movable core 26 is fixed to the valve member 22 on the side opposite to the valve seat 17 by welding or the like. In the first embodiment, the center of gravity 200 of the movable member 20 is substantially at the same position as the locking portion 24 where the movable member 20 locks the spring 29. The movable core 26 has a small diameter portion 27 from the valve seat 17 side, and a large diameter portion 28 having an outer diameter larger than that of the small diameter portion 27 in this order. The large diameter portion 28 is provided on the opposite side of the valve seat 17 with respect to the locking portion 24 of the valve member 22. That is, the locking portion 24 is located closer to the valve seat 17 than the support location where the movable core 26 is supported by the magnetic pipe 13. The movable core 26 has a large diameter portion 28 supported by the inner peripheral wall of the magnetic pipe 13. When the sliding clearance between the large diameter portion 28 and the magnetic pipe 13 is δ (see FIG. 3), it is desirable that 10 μm ≦ δ ≦ 150 μm.

As shown in FIG. 2, the spring 29 as an urging member has one end locked to the locking portion 24 of the valve member 22 and the other end locked to an adjusting pipe 32 press-fitted into the fixed core 30. ing. The fixed core 30 is attached and fixed in the pipe member 12.
The coil 40 is wound around a bobbin 42 and is installed on the outer periphery of the nonmagnetic pipe 14. The yoke 44 covers the outer periphery of the coil 40, is connected to the magnetic pipe 13 on the radially outer side of the movable core 26, and is connected to the nonmagnetic pipe 14 on the radially outer side of the fixed core 30. The resin housing 50 covers the outer periphery of the pipe member 12, the coil 40, and the yoke 44. The terminal 52 is electrically connected to the coil 40 and supplies a drive current to the coil 40.

Next, the operation of the fuel injection valve 10 will be described.
When the coil 40 is energized, a magnetic flux flows through a magnetic circuit formed by the yoke 44, the magnetic pipe 13, the nonmagnetic pipe 14, the movable core 26, and the fixed core 30. Since both the yoke 44 and the magnetic pipe 13 are made of a magnetic material, the magnetic resistance between the yoke 44 and the movable core 26 is small. On the other hand, the nonmagnetic pipe 14 is sandwiched between the yoke 44 and the fixed core 30. However, since the nonmagnetic pipe 14 is thin, the magnetic flux sufficiently passes between the end 46 of the yoke 44 and the fixed core 30. Therefore, the magnetic resistance between the yoke 44 and the fixed core 30 is reduced. When magnetic flux flows through the magnetic circuit, a magnetic attractive force is generated between the fixed core 30 and the movable core 26, and the movable core 26 is attracted to the fixed core 30 side. Then, as the movable core 26 is attracted toward the fixed core 30, the valve member 22 moves upward in FIG. 2 and the contact portion 23 is separated from the valve seat 17. Thereby, fuel is injected from the nozzle hole 18a formed in the nozzle hole plate 18.

When energization of the coil 40 is stopped, the magnetic attractive force between the fixed core 30 and the movable core 26 disappears. As a result, the movable core 26 moves away from the fixed core 30 by the urging force of the spring 29. The valve member 22 also moves away from the fixed core 30, that is, toward the valve seat 17.
At this time, since the locking portion 24 of the valve member 22 that locks the spring 29 is positioned on the valve seat 17 side with respect to the center of gravity 200 of the movable member 20, the movable member 20 moves toward the valve seat. The axial deviation and inclination of the movable member 20 can be reduced. As a result, variations in the seating position when the valve member 22 is seated on the valve seat 17 can be reduced. Therefore, variations in the fuel injection amount can be prevented. In addition, it is possible to prevent deterioration of valve tightness when the valve is closed.

Further, since the valve seat 17 is formed in a conical shape whose diameter is reduced toward the nozzle hole 18a, even if the seating position of the valve member 22 is shifted, the valve member 22 is aligned by being guided by the conical surface. The centers of the seat 17 and the valve member 22 coincide.
In the first embodiment, the large-diameter portion 28 of the movable core 26 is supported by the magnetic pipe 13 and slides with the magnetic pipe 13, and the small-diameter portion 27 whose outer diameter is smaller than the large-diameter portion 28 almost slides with the magnetic pipe 13. Does not move. With this configuration, the sliding length of the movable core 26 and the magnetic pipe 13 in the reciprocating direction is shortened, so that the sliding resistance of the movable core 26 is reduced. Therefore, the movable member 20 is supported by the magnetic pipe 13 and reciprocates smoothly.

(Deformation 1, 2)
Modifications 1 and 2 of the first embodiment are shown in FIGS. 4 and 5. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment.
In the first embodiment, the movable core 26 is provided with a small diameter portion 27 and a large diameter portion 28 having an outer diameter larger than the small diameter portion 27, and the large diameter portion 28 is supported by the inner peripheral wall of the magnetic pipe 13. On the other hand, in the modification 1 of 1st Embodiment shown in FIG. 4, the outer diameter of the movable core 65 is made into the same diameter. However, as in the first embodiment, the center of gravity 200 of the movable member made up of the valve member 22 and the movable core 65 is substantially at the same position as the locking portion 24 that locks the spring 29.

  In the second modification of the first embodiment shown in FIG. 5, the locking portion 24 of the movable member 20 that locks the spring 29 is on the valve seat 17 side from the center of gravity 200 of the movable member 20 including the valve member 22 and the movable core 26. Is located. Therefore, when the movable member 20 moves toward the valve seat 17 by the urging force of the spring 29, the axial deviation and inclination of the movable member 20 can be reduced.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment.
The movable member 70 of the second embodiment includes a ball 72, a cylindrical member 74, and a movable core 26. The center of gravity 200 of the movable member 20 is at substantially the same position as the locking portion 75 of the cylindrical member 74 that locks the spring 29. The ball 72, which is a valve member, can be seated on a valve seat 77 formed on a valve body 76, which is a valve seat member. The valve seat 77 is a conical surface that decreases in diameter toward the nozzle hole 18a.

(Third embodiment)
A third embodiment of the present invention is shown in FIGS. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment.
The movable member 90 of the fuel injection valve 80 of the third embodiment has a valve member 92 and a movable core 94. The valve member 92 is formed in a solid cylindrical shape.

  The movable core 94 is fixed to the side of the valve member 92 opposite to the valve seat 17 by welding or the like. As shown in FIG. 8, a communication path 120 is formed on the outer periphery of the movable core 94. The fuel that has passed through the inside of the fixed core 30 reaches the valve portion formed by the valve member 92 and the valve seat 17 from the communication passage 120. A recess is formed on the spring 29 side of the movable core 94. The bottom inner wall of the recess is a locking portion 95 that locks the spring 29. The center of gravity 200 of the movable member 90 is substantially the same position as the locking portion 95. Moreover, the latching | locking part 95 is located in the range of the axial direction of the support location which the magnetic pipe 13 supports the movable core 94 so that reciprocation is possible.

In the plurality of embodiments described above, the engaging portion of the movable member that engages the spring 29 is located at substantially the same position as the center of gravity 200 of the movable member or closer to the valve seat than the center of gravity 200. That is, the force point of the urging force that urges the movable member toward the valve seat by the spring 29 is substantially the same position as the center of gravity 200 of the movable member or is located on the valve seat side with respect to the center of gravity 200. According to this configuration, it is possible to reduce the axial deviation and inclination of the movable member when the movable member moves toward the valve seat by the biasing force of the spring 29. As a result, as in the above-described embodiments, even when the support member supports the valve member so that the support member can reciprocate in one place in the reciprocating direction, the variation in the seating position at which the movable member sits on the valve seat is varied. Can be reduced. In addition, it is possible to prevent deterioration of valve tightness when the valve is closed. Therefore, it is easy to process the magnetic pipe 13 that is a support member that supports the movable member so as to reciprocate.
Also, since the support member supports the movable member so that the support member can reciprocate is one place in the reciprocation direction, even if the seating position of the valve member seated on the valve seat deviates from the center of the valve seat, By guiding the valve member along the conical surface, the displacement of the seating position of the valve member can be easily corrected.

(Other embodiments)
In the first embodiment and the modification thereof, the locking portion 24 of the movable member 20 that locks the spring 29 is substantially the same as the center of gravity 200 of the movable member 20 or is located on the valve seat 17 side, and is magnetic. It is located closer to the valve seat 17 than the support location of the movable member 20 supported by the pipe 13. On the other hand, if the locking part 24 of the movable member 20 is substantially the same as the center of gravity 200 of the movable member 20 or is located on the valve seat 17 side, the locking part 24 is supported by the magnetic pipe 13. It may be positioned substantially the same as the support location of the movable member 20 or on the opposite side of the valve seat 17 with respect to the locking portion 24.

In the first embodiment, the desired sliding clearance δ between the movable core 26 and the magnetic pipe 13 is in the range of 10 μm ≦ δ ≦ 150 μm. However, in the present invention, other sliding clearances are set. May be.

It is sectional drawing which shows the circumference | surroundings of the movable member of the fuel injection valve by 1st Embodiment of this invention. It is sectional drawing which shows the fuel injection valve by 1st Embodiment. It is sectional drawing which shows the circumference | surroundings of the movable member of the fuel injection valve by 1st Embodiment. It is sectional drawing which shows the circumference | surroundings of the movable member by the modification 1 of 1st Embodiment. It is sectional drawing which shows the circumference | surroundings of the movable member by the modification 2 of 1st Embodiment. It is sectional drawing which shows the circumference | surroundings of the movable member of the fuel injection valve by 2nd Embodiment. It is sectional drawing which shows the fuel injection valve by 3rd Embodiment. It is sectional drawing which shows the circumference | surroundings of the movable member of the fuel injection valve by 3rd Embodiment.

Explanation of symbols

  10, 80 Fuel injection valve, 13 Magnetic pipe (support member), 16, 76 Valve body (valve seat member), 17, 77 Valve seat, 18a Injection hole, 20, 70, 90 Movable member, 22, 92 Valve member, 24, 75, 95 Locking part, 26, 94 Movable core, 29 Spring (biasing member), 30 Fixed core, 40 coils, 72 balls (valve member), 200 Center of gravity

Claims (4)

A valve member for intermittently injecting fuel from the nozzle hole, and a movable member having a movable core that reciprocally moves together with the valve member;
A cone that shuts off fuel injection from the nozzle hole when the valve member is seated, and allows fuel injection from the nozzle hole when the valve member is seated and contracts toward the nozzle hole side. A valve seat member having a shaped valve seat;
A biasing member that biases the movable member toward the valve seat;
A support member that supports the movable member in a reciprocating manner;
A fixed core that is installed on the opposite side of the nozzle hole to the movable core and faces the movable core, and generates a magnetic attractive force between the movable core;
A coil that generates a magnetic attractive force between the movable core and the fixed core by energization;
With
The locking portion of the movable member that locks the biasing member is substantially the same as the center of gravity of the movable member,
Located on the valve seat side from the center of gravity,
The movable member is supported by only the support member in the reciprocating direction when the movable member is separated from the valve seat, and is supported by only one place of the support member. Injection valve.   2. The fuel injection valve according to claim 1, wherein the locking portion is located closer to the valve seat than a portion where the movable member is supported by the support member.   3. The fuel injection valve according to claim 1, wherein the movable core is installed on a side of the valve member opposite to the valve seat, and the support member supports the movable core so as to be capable of reciprocating. 4.   4. The fuel injection valve according to claim 1, wherein a sliding clearance between the movable member and the support member is δ, and 10 μm ≦ δ ≦ 150 μm. 5.

Images