JP2005351203A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injector with a simple structure capable of reducing bound of a movable core and a valve member and showing little change in the fuel injection characteristic without increasing the number of components. <P>SOLUTION: An abutting part between a fixed core 40 and the movable core 50 is formed with a first inclined face 52 and a second inclined face 42. The first inclined face 52 and the second inclined face 42 are inclined relative to an axis. An impact force applied to the first inclined face 52 by a collision between the movable core 50 and the fixed core 40 is dispersed to the axial direction and to the radial direction. As a result, a component force in the axial direction of the impact force on the movable core 50 is reduced. Thereby, when the movable core 50 collides against the fixed core 40, a force for moving the movable core 50 to the opposite direction of the fixed core 40 by the impact force is reduced. Accordingly, the bound of the movable core 50 can be reduced and uncontrollable fuel injection can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel injection valve (hereinafter, the fuel injection valve is referred to as an “injector”).

  2. Description of the Related Art Conventionally, an injector that drives a valve member integrated with a movable core using a magnetic attractive force generated between the fixed core and the movable core by energizing a coil is known. In the case of such an injector, the valve member reciprocates in the axial direction as the coil is energized. Therefore, the movable core collides with the fixed core when moving in the direction of the fixed core, and the integral valve member collides with the valve seat when moving to the opposite side of the fixed core. As a result, a so-called bounce occurs in the movable core and the valve member due to the impact at the time of collision.

  In the case of an injector, when a bounce occurs in the valve member, the injection hole opens and closes irregularly with the bounce. As a result, uncontrollable fuel injection without reproducibility is caused from the injection hole. In particular, when the frequency of the energization pulse to the coil is low, the influence of the bounce increases, and the fuel injection amount and the shape of the fuel spray cannot be controlled with high accuracy. Therefore, an injector in which two stoppers are installed on the valve member and a movable core is disposed between the stoppers is known (see Patent Document 1).

Japanese translation of PCT publication No. 2002-528672

  In the injector disclosed in Patent Document 1, the movable core is movable in the axial direction between two stoppers. Thereby, when a valve member and another member collide, the inertia force of a mutually reverse direction will arise in a valve member and a movable core, and the impact in a collision site | part will be relieved. Furthermore, by installing a shock-absorbing spring between the movable core and the stopper, the impact caused by the collision is reduced and the occurrence of bounce is reduced.

  However, in the technique disclosed in Patent Document 1, it is necessary to install two stoppers on the valve member and install a movable core between the two stoppers so as to be movable with respect to the valve member. Furthermore, it is necessary to install a buffer spring between the movable core and the stopper. Therefore, there is a problem that the structure is complicated and the number of parts is increased. In addition, with the operation of the injector over a long period of time, it causes spring sag and wear. For this reason, the characteristics of the spring change over time, and it becomes difficult to ensure fuel injection characteristics that are stable for a long time.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an injector that has a simple structure, reduces the bounds of the movable core and the valve member, and causes little change in fuel injection characteristics without increasing the number of parts.

  In the present invention, the first inclined surface of the movable core and the second inclined surface of the fixed core are inclined with respect to the central axis. The first inclined surface and the second inclined surface form a contact portion. Thereby, when a movable core is attracted | sucked by the fixed core, the 1st inclined surface and 2nd inclined surface which the fixed core and the movable core mutually incline contact. Therefore, the impact force of the collision between the fixed core and the movable core is dispersed in the axial direction and the radial direction of the fixed core and the movable core. As a result, the impact in the axial direction of the fixed core and the movable core is reduced. Therefore, the bounce of the movable core and the valve member integral with the movable core can be reduced. Moreover, the relaxation of the impact is achieved by installing the first inclined surface on the movable core and installing the second inclined surface on the fixed core. Therefore, the installation of another member and the structure are not complicated, and the change in characteristics over time does not occur. Therefore, the number of parts is not increased, the bound of the movable core can be reduced with a simple structure, and a stable fuel injection characteristic can be obtained for a long time.

  In the invention according to claim 5, the movable core forms the first inclined surface on the inner peripheral wall of the tapered portion which is recessed toward the injection hole. During the operation of the injector, the movable core reciprocates in the axial direction. Therefore, in order to reduce the bounce and increase the response during driving, it is desirable that the mass of the movable core is small. By forming the tapered portion that is recessed toward the injection hole in the movable core, the volume of the movable core is reduced corresponding to the recessed tapered portion. As a result, the mass of the movable core is also reduced. Therefore, the bound of the movable core is reduced and the responsiveness can be improved.

  In the invention according to claim 6, the first inclined surface and the second inclined surface are respectively installed at the radially outer ends of the movable core and the fixed core. By installing the first inclined surface and the second inclined surface outside the movable core and the fixed core in the radial direction, the areas of the first inclined surface and the second inclined surface are expanded. Therefore, when the movable core collides with the fixed core, the area that receives the impact of the collision increases. As a result, the impact force caused by the collision between the movable core and the fixed core is further alleviated. Therefore, bounce can be reduced.

  According to the seventh aspect of the present invention, at least one of the movable core and the fixed core has a step portion that forms a gap with the opposed fixed core or movable core. The step portion is provided on the radially outer side or the radially inner side of the first inclined surface or the second inclined surface. Since the periphery of the movable core and the fixed core is filled with fuel, the gap is filled with fuel by forming a gap between the movable core and the fixed core by the stepped portion. Therefore, when the movable core moves toward the fixed core, the fuel is discharged while being compressed in the gap. As a result, the impact between the movable core and the fixed core is mitigated by the fuel in the gap. That is, the fuel in the gap produces a damper effect. Therefore, the impact caused by the collision between the movable core and the fixed core can be reduced, and the bounce can be reduced.

Hereinafter, a plurality of embodiments of the present invention will be described based on the drawings.
(First embodiment)
FIG. 2 shows a fuel injection valve (hereinafter referred to as “injector”) according to the first embodiment of the present invention. The injector 10 according to the first embodiment is applied to, for example, a direct injection gasoline engine. The injector 10 may be applied not only to a direct-injection gasoline engine but also to a premixed gasoline engine or a diesel engine. When the injector 10 is applied to a direct-injection gasoline engine, the injector 10 is mounted on a cylinder head (not shown).

  The housing 11 of the injector 10 is formed in a cylindrical shape. The housing 11 has a first magnetic part 12, a nonmagnetic part 13, and a second magnetic part 14. The nonmagnetic part 13 prevents a magnetic short circuit between the first magnetic part 12 and the second magnetic part 14. The first magnetic part 12, the nonmagnetic part 13, and the second magnetic part 14 are integrally connected by, for example, laser welding. Note that the portion corresponding to the non-magnetic portion 13 may be made non-magnetic by molding the housing 11 into a single piece with a magnetic material and performing heat processing.

  An inlet member 15 is installed at one end of the housing 11 in the axial direction. The inlet member 15 is press-fitted on the inner peripheral side of the housing 11. The inlet member 15 has a fuel inlet 16. Fuel is supplied to the fuel inlet 16 from a fuel pump (not shown). The fuel supplied to the fuel inlet 16 flows into the inner peripheral side of the housing 11 via the fuel filter 17. The fuel filter 17 removes foreign matters contained in the fuel.

  A nozzle holder 20 is installed at the other end of the housing 11. The nozzle holder 20 is formed in a cylindrical shape, and a nozzle body 21 is installed inside. The nozzle body 21 is formed in a cylindrical shape, and is fixed to the nozzle holder 20 by, for example, press fitting or welding. The nozzle body 21 has a valve seat 22 on a conical inner wall surface whose inner diameter decreases as it approaches the tip. The nozzle body 21 has an injection hole 23 that penetrates the nozzle body 21 and connects the inner wall surface and the outer wall surface in the vicinity of the end opposite to the housing 11.

  The needle 24 as a valve member is accommodated on the inner peripheral side of the housing 11, the nozzle holder 20 and the nozzle body 21 so as to be reciprocally movable in the axial direction. The needle 24 is disposed substantially coaxially with the nozzle body 21. The needle 24 has a seal portion 25 at the end opposite to the fuel inlet 16 in the axial direction. The seal portion 25 can come into contact with the valve seat 22 formed on the nozzle body 21. The needle 24 forms a fuel passage 26 through which fuel flows between the needle 24 and the needle body 21.

  The injector 10 has a drive unit 30 that drives the needle 24. The drive unit 30 includes a spool 31, a coil 32, a fixed core 40, a plate housing 33, and a movable core 50. The spool 31 is installed on the outer peripheral side of the housing 11. The spool 31 is formed of a resin in a cylindrical shape, and a coil 32 is wound on the outer peripheral side. The coil 32 is connected to the terminal portion 35 of the connector 34. A fixed core 40 is installed on the inner peripheral side of the coil 32 with the housing 11 in between. The fixed core 40 is formed in a cylindrical shape from a magnetic material such as iron, and is fixed to the inner peripheral side of the housing 11 by, for example, press fitting. The plate housing 33 is made of a magnetic material and covers the outer peripheral side of the coil 32.

  The movable core 50 is disposed coaxially with the fixed core 40. The movable core 50 is installed on the inner peripheral side of the housing 11 so as to be capable of reciprocating in the axial direction. The movable core 50 is formed in a cylindrical shape from a magnetic material such as iron. In the movable core 50, the needle 24 is fixed to the end opposite to the fixed core 40. The movable core 50 is in contact with the spring 18 that is an elastic member at the end on the fixed core 40 side. One end of the spring 18 is in contact with the movable core 50 in the axial direction. An adjusting pipe 19 is press-fitted into the fixed core 40. The other end of the spring 18 is in contact with the adjusting pipe 19. The spring 18 has a force in a direction extending in the axial direction. Therefore, the movable core 50 and the needle 24 integrated with the movable core 50 are pressed by the spring 18 in the direction of seating on the valve seat 22. The load of the spring 18 is adjusted by adjusting the press-fitting amount of the adjusting pipe 19 that is press-fitted into the fixed core 40. When the coil 32 is not energized, the movable core 50 and the needle 24 integrated with the movable core 50 are pressed toward the valve seat 22, and the seal portion 25 is seated on the valve seat 22.

Next, the fixed core 40 and the movable core 50 of the drive unit 30 will be described in detail.
As shown in FIG. 1, the movable core 50 has a truncated cone-shaped base 51 projecting toward the fixed core 40 at the end on the fixed core 40 side. The outer diameter of the pedestal 51 decreases as the distance from the nozzle hole 23 increases. Therefore, the outer peripheral surface of the base 51 is a first inclined surface 52 that is inclined with respect to the central axis of the movable core 50. The distance from the central axis of the movable core 50 becomes shorter as the first inclined surface 52 is further away from the nozzle hole 23. On the other hand, the fixed core 40 has a truncated conical recess 41 that is recessed toward the side opposite to the movable core 50 at the end on the movable core 50 side. The outer diameter of the recess 41 decreases as the distance from the nozzle hole 23 increases. Therefore, the inner peripheral surface of the recess 41 is a second inclined surface 42 that is inclined with respect to the central axis of the fixed core 40. Similarly to the first inclined surface 41, the second inclined surface 42 also has a shorter distance from the central axis of the fixed core 40 as the distance from the injection hole 23 increases.

  The base 51 is installed on the inner peripheral side of the movable core 50. That is, the pedestal 51 is installed on the central axis side of the movable core 50. In addition, the recess 41 is disposed so as to face the base 51 of the movable core 50. Therefore, the recess 41 is installed on the inner peripheral side of the fixed core 40. The angle θ1 formed by the first inclined surface 52 with respect to the central axis of the movable core 50 is substantially the same as the angle θ2 formed by the second inclined surface 42 with respect to the central axis of the fixed core 40. The movable core 50 and the fixed core 40 are arranged coaxially. Therefore, the first inclined surface 52 and the second inclined surface 42 are substantially parallel.

  As shown in FIG. 3, when the movable core 50 is sucked by the fixed core 40, the first inclined surface 52 can contact the second inclined surface 42. When a magnetic attractive force is generated between the fixed core 40 and the movable core 50, the movable core 50 moves toward the fixed core 40 in the upper direction of FIG. 2, that is, along the central axis. When the movable core 50 moves to the fixed core 40 side, the movable core 50 collides with the end of the fixed core 40 on the injection hole 23 side. At this time, the first inclined surface 52 and the second inclined surface 42 come into contact with each other to form the contact portion 60. When the movable core 50 collides with the fixed core 40, an impact force Fa is applied perpendicularly to the first inclined surface 52 forming the contact portion 60 as shown in FIG. The first inclined surface 52 is inclined with respect to the central axis. Therefore, the impact force Fa applied perpendicularly to the first inclined surface 52 is dispersed into the component force fp in the central axis direction and the component force fr in the radial direction.

  The bounce of the movable core 50 caused by the collision between the movable core 50 and the fixed core 40 is related to the magnitude of the force in the central axis direction among the impact forces of the collision. That is, the greater the force in the central axis direction of the impact force of the collision, the greater the bounce of the movable core 50 and the needle 24 integrated with the movable core 50. In the case of the present embodiment, the impact force Fa is formed by forming the contact portion 60 from the first inclined surface 52 and the second inclined surface 42 that are inclined with respect to the central axis, so that the impact force Fa is equal to the component force fp and the diameter in the central axis direction. It is distributed to the component force fr in the direction. Therefore, the component force fp in the central axis direction of the impact force applied to the contact portion 60 is reduced. As a result, the distance that the integral movable core 50 and the needle 24 move downward in FIG. 2 due to the impact of the collision is reduced, and the bounce of the integral movable core 50 and the needle 24 is reduced.

  In order to reduce the component force fp in the central axis direction of the impact force of the collision, the angles θ1 and θ2 formed by the first inclined surface 52 and the second inclined surface 42 and the central axis are preferably close to 90 °. That is, when the same impact force Fa is applied to the contact portion 60, the component force fp in the central axis direction decreases and the radial component force fr increases as θ1 and θ2 approach 90 °. On the other hand, the closer the θ1 and θ2 are to 90 °, the longer the axial lengths of the base 51 and the recess 41, leading to an increase in the size of the fixed core 40 and the movable core 50. Therefore, it is desirable to determine θ1 and θ2 in consideration of the influence on the bounds and the physiques of the fixed core 40 and the movable core 50.

Next, the operation of the injector 10 having the above configuration will be described.
When energization of the coil 32 is stopped, no magnetic attractive force is generated between the fixed core 40 and the movable core 50. Therefore, the integral movable core 50 and the needle 24 are moved to the opposite side of the fixed core 40 by the pressing force of the spring 18. As a result, when energization to the coil 32 is stopped, the seal portion 25 of the needle 24 is seated on the valve seat 22. Therefore, fuel is not injected from the injection hole 23.

  When the coil 32 is energized, the magnetic field generated in the coil 32 causes a magnetic flux to flow through the plate housing 33, the first magnetic part 12, the movable core 50, the fixed core 40, and the second magnetic part 14, thereby forming a magnetic circuit. . As a result, a magnetic attractive force is generated between the fixed core 40 and the movable core 50. When the magnetic attractive force generated between the fixed core 40 and the movable core 50 becomes larger than the pressing force of the spring 18, the movable core 50 moves to the fixed core 40 side. Therefore, the needle 24 moves to the fixed core 40 side with the movement of the movable core 50. As a result, the seal portion 25 of the needle 24 is separated from the valve seat 22. The movable core 50 moves toward the fixed core 40 until it collides with the end of the fixed core 40 on the nozzle hole 23 side, that is, until the first inclined surface 52 and the second inclined surface 42 come into contact with each other. When the movable core 50 collides with the fixed core 40, the movement toward the fixed core 40, that is, the lift is restricted.

  The fuel that flows into the injector 10 from the fuel inlet 16 passes through the fuel filter 17, the inner peripheral side of the inlet member 15, the inner peripheral side of the adjusting pipe 19, the inner peripheral side of the movable core 50, and the movable core 50. It flows into the fuel passage 26 via the fuel hole 53 connecting the peripheral side and the outer peripheral side and the inner peripheral side of the nozzle holder 20. The fuel that has flowed into the fuel passage 26 flows into the nozzle hole 23 via the space between the needle 24 and the nozzle body 21 that are separated from the valve seat 22. Thereby, fuel is injected from the injection hole 23.

  When energization of the coil 32 is stopped, the magnetic attractive force between the fixed core 40 and the movable core 50 disappears. The movable core 50 and the needle 24 are integrally moved by the pressing force of the spring 18 to the side opposite to the fixed core 40. Therefore, the seal portion 25 is seated on the valve seat 22 again, and the flow of fuel between the fuel passage 26 and the injection hole 23 is blocked. Therefore, the fuel injection ends.

  As described above, in the first embodiment, the contact portion 60 between the fixed core 40 and the movable core 50 is formed by the first inclined surface 52 and the second inclined surface 42. The first inclined surface 52 and the second inclined surface 42 are inclined with respect to the central axis. Therefore, the impact force applied to the first inclined surface 52 by the collision between the movable core 50 and the fixed core 40 is dispersed in the central axis direction and the radial direction. As a result, the component force in the central axis direction of the impact force applied to the movable core 50 decreases. Thereby, when the movable core 50 and the fixed core 40 collide, the force to move the movable core 50 to the opposite side of the fixed core 40 by the impact force is reduced. Therefore, the bounce of the movable core 50 can be reduced, and uncontrollable fuel injection can be reduced.

  In the first embodiment, the bounce of the movable core 50 is reduced by installing the first inclined surface 52 on the movable core 50 and installing the second inclined surface 42 on the fixed core 40. Therefore, it is not necessary to install a complicated shock absorbing mechanism or buffer mechanism around the movable core 50. Therefore, the number of parts is not increased and the structure is not complicated. Moreover, the injector 10 of 1st Embodiment does not relieve | impact the impact force of the collision with the movable core 50 and the fixed core 40 by elastic members, such as a spring, for example. Therefore, the change with time of the impact relaxation characteristics is reduced. Therefore, fuel injection characteristics that are stable for a long time can be obtained.

  In the first embodiment, the movable core 50 and the fixed core 40 are changed by changing the angles of the first inclined surface 52 and the second inclined surface 42 and the areas of the first inclined surface 52 and the second inclined surface 42. The impact relaxation characteristics at the time of collision change. Therefore, the bounce characteristics of the movable core 50 change by adjusting the angles and areas of the first inclined surface 52 and the second inclined surface 42. Therefore, the bounce characteristics of the movable core 50 can be easily controlled.

(Second Embodiment)
The principal part of the injector by 2nd Embodiment of this invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In 2nd Embodiment, as shown in FIG. 4, the movable core 50 has the protrusion part 54 which protrudes in the fixed core 40 side in the edge part of a radial direction outer side. The protruding portion 54 is arranged in an annular shape continuously in the circumferential direction of the movable core 50. The inner peripheral surface of the protrusion 54 forms a first inclined surface 55 whose inner diameter becomes smaller as it approaches the injection hole 23. Thereby, the distance from the central axis of the first inclined surface 55 becomes shorter as it approaches the nozzle hole 23. On the other hand, the fixed core 40 has a second inclined surface 43 corresponding to the first inclined surface 55 on the outer peripheral surface of the end portion on the movable core 50 side. Therefore, the distance from the central axis of the second inclined surface 43 becomes shorter as it approaches the nozzle hole 23. The 1st inclined surface 55 and the 2nd inclined surface 43 are substantially parallel like 1st Embodiment.

By installing the first inclined surface 55 and the second inclined surface 43 at the radially outer ends of the movable core 50 and the fixed core 40, the first inclined surface 55 and the second inclined surface 43 are installed on the radially inner side. Compared with the time, the contact area in the contact part of the 1st inclined surface 55 and the 2nd inclined surface 43 expands. That is, the area receiving the impact force generated by the collision between the movable core 50 and the fixed core 40 is expanded. As a result, if the impact force is constant, the pressure received by the movable core 50 at the time of the collision between the movable core 50 and the fixed core 40 decreases. Thereby, the impact applied to the movable core 50 at the time of the collision between the movable core 50 and the fixed core 40 is further alleviated without increasing the size of the movable core 50 and the fixed core 40. Therefore, the bound of the integral movable core 50 and the needle 24 can be further reduced.
In addition, in 2nd Embodiment, the example which installs the protrusion part 54 which protrudes from the movable core 50 to the fixed core 40 was demonstrated. However, the fixed core 40 may be provided with a protruding portion that protrudes toward the movable core 50 side. That is, the uneven shapes of the fixed core 40 and the movable core 50 may be reversed.

(Third and fourth embodiments)
The main part of the injector according to the third and fourth embodiments of the present invention is shown in FIG. 5 or FIG. 6, respectively. In addition, the same code | symbol is attached | subjected to the structure substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In the third embodiment, as shown in FIG. 5, the movable core 150 has a truncated cone-shaped first inclined surface 151 on the entire end portion on the fixed core 140 side. That is, the first inclined surface 151 is formed from the radially inner end to the outer end at the end of the movable core 150 on the fixed core 140 side. The first inclined surface 151 has a shorter distance from the central axis as the distance from the nozzle hole 23 increases.

  The fixed core 140 has a truncated cone-shaped second inclined surface 141 on the entire end on the movable core 150 side corresponding to the first inclined surface 151 of the movable core 150. The inner diameter of the second inclined surface 141 decreases as the distance from the nozzle hole 23 increases. For this reason, the distance from the central axis of the second inclined surface 141 decreases as the distance from the nozzle hole 23 increases. The second inclined surface 141 is substantially parallel to the first inclined surface 151.

  In the third embodiment, the end portion on the fixed core 140 side of the movable core 150 and the end portion on the movable core 150 side of the fixed core 140 respectively form a first inclined surface 151 and a second inclined surface 141 as a whole. Therefore, the contact area at the contact portion between the first inclined surface 151 and the second inclined surface 141 is increased. As a result, if the impact force is constant, the pressure received by the movable core 150 at the time of collision between the movable core 150 and the fixed core 140 decreases. Thereby, the impact applied to the movable core 150 at the time of the collision between the movable core 150 and the fixed core 140 is further alleviated. Therefore, the bounce of the integral movable core 150 and the needle 24 can be further reduced.

In 4th Embodiment, as shown in FIG. 6, the inclination of the 1st inclined surface 151 formed in the movable core 150 and the 2nd inclined surface 141 formed in the fixed core 140 is contrary to 3rd Embodiment. That is, the first inclined surface 151 and the second inclined surface 141 have a shorter distance from the central axis as they approach the injection hole 23.
In the fourth embodiment, as in the third embodiment, the pressure received by the movable core 150 when the movable core 150 and the fixed core 140 collide with each other decreases. Therefore, the bounce of the integral movable core 150 and the needle 24 can be further reduced.

(Fifth embodiment)
The principal part of the injector by 5th Embodiment of this invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In the fifth embodiment, as shown in FIG. 7, the movable core 50 has a protruding portion 56 that protrudes toward the fixed core 40 at the end portion on the fixed core 40 side. The protruding portion 56 is installed on the outer side in the radial direction of the pedestal 51 and is formed in an annular shape that continuously surrounds the pedestal 51 in the circumferential direction. The protrusion 56 is an inclined surface 57 whose outer peripheral surface is substantially parallel to the first inclined surface 52, and whose inner peripheral surface is a vertical surface 58 substantially parallel to the central axis. Thereby, the movable core 50 has the double annular base part 51 and the protrusion part 56 which protrude toward the fixed core 40 side at the end part on the fixed core 40 side.

  On the other hand, the fixed core 40 has an annular groove 44 on the radially outer side of the recess 41 corresponding to the shape of the end of the movable core 50 on the fixed core 40 side. In the annular groove 44, the outer peripheral surface is an inclined surface 45 substantially parallel to the inclined surface 57 of the movable core 50, and the inner peripheral surface is a vertical surface 46 substantially parallel to the central axis. Thereby, the fixed core 40 has the recessed part 41 and the annular groove part 44 which are depressed in the edge part by the side of the movable core 50 to the opposite side to the movable core 50. FIG.

  The depth of the annular groove 44, that is, the total length in the axial direction of the annular groove 44 is slightly larger than the height of the projection 56, that is, the total length in the axial direction of the projection 56. Therefore, a gap 61 is formed between the protrusion 56 and the annular groove 44 at the end of the protrusion 56 opposite to the nozzle hole 23. Thereby, the protrusion part 56 and the annular groove part 44 respond | correspond to the level | step-difference part of a claim. The fuel supplied from the fuel inlet 16 to the inside of the injector 10 fills the inside of the injector 10 including the periphery of the movable core 50 and the fixed core 40. Therefore, the fuel existing around the movable core 50 and the fixed core 40 is filled between the movable core 50 and the fixed core 40 facing each other. Therefore, fuel is stored in the gap 61.

  When the movable core 50 is attracted toward the fixed core 40, the volume of the gap 61 decreases as the movable core 50 moves. Therefore, the fuel stored in the gap 61 is compressed and flows out between the wall surface of the movable core 50 that forms the protruding portion 56 and the wall surface of the fixed core 40 that forms the annular groove portion 44. As a result, the fuel stored in the gap 61 has a buffering action and alleviates the impact at the time of the collision between the movable core 50 and the fixed core 40. That is, a damper effect is generated between the movable core 50 and the fixed core 40 by the fuel stored in the gap 61.

  In the fifth embodiment, the contact area at the contact portion between the movable core 50 and the fixed core 40 is increased by forming the protrusion 56 and the annular groove 44. Therefore, the pressure received by the movable core 50 when the movable core 50 and the fixed core 40 collide decreases. Therefore, the bound of the integral movable core 50 and the needle 24 can be further reduced. In addition, the impact caused by the collision between the movable core 50 and the fixed core 40 is mitigated by the damper effect of the fuel stored in the gap 61. Therefore, the bound of the integral movable core 50 and the needle 24 can be further reduced.

  In the fifth embodiment, the example in which the inclined surface 57 and the inclined surface 45 are formed substantially parallel to the first inclined surface 52 and the second inclined surface 42 has been described. However, the inclined surface 57 and the inclined surface 45 and the first inclined surface 52 and the second inclined surface 42 may give an arbitrary difference in angle, and are not limited to being substantially parallel. Further, the vertical surface 58 and the vertical surface 46 are not limited to surfaces parallel to the central axis, and may be formed at an arbitrary angle.

(Sixth embodiment)
The principal part of the injector by 6th Embodiment of this invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In the sixth embodiment, as shown in FIG. 8, the movable core 250 has a tapered portion 251 that is recessed radially inward from the opposite side of the fixed core 240. The tapered portion 251 has an inner diameter that is closer to the nozzle hole 23. Thereby, the taper part 251 forms the 1st inclined surface 252 in the internal peripheral surface. As a result, the distance between the first inclined surface 252 and the central axis becomes shorter as it approaches the nozzle hole 23. The fixed core 240 has a tapered portion 241 that protrudes toward the movable core 250 corresponding to the tapered portion 251 on the radially inner side. Thereby, the taper part 241 forms the 2nd inclined surface 242 in which an internal diameter becomes small as it approaches the nozzle hole 23 in an outer peripheral surface. Thereby, the distance between the second inclined surface 242 and the central axis decreases as the nozzle hole 23 is approached. Moreover, the 1st inclined surface 252 and the 2nd inclined surface 242 are substantially parallel.

  In the sixth embodiment, the movable core 250 is formed with a tapered portion 251 that is recessed to the opposite side of the fixed core 240, for example, compared with the case where the base portion 51 protrudes from the movable core 50 as in the first embodiment. As a result, the volume of the movable core 250 decreases. Therefore, the mass of the movable core 250 decreases. Since the movable core 250 is driven by a magnetic attractive force generated between the movable core 250 and the fixed core 240, the moment of inertia decreases as the mass decreases. Thereby, the operation responsiveness of the movable core 250 can be improved by reducing the mass of the movable core 250. Therefore, it is possible to reduce the bounce of the integral movable core 250 and the needle 24 and to reliably inject fuel at a short cycle.

  In the plurality of embodiments described above, the injector 10 that forms the nozzle hole 23 in the nozzle body 21 is shown as an example. However, for example, a nozzle hole forming member that forms a nozzle hole at the tip of the nozzle body 21 may be installed. Moreover, you may apply to the injector 10 combining several embodiment.

It is sectional drawing to which the fixed core and movable core of the injector by 1st Embodiment of this invention were expanded. It is sectional drawing which shows the injector by 1st Embodiment of this invention. It is sectional drawing to which the fixed core and movable core of the injector by 1st Embodiment of this invention were expanded. It is sectional drawing to which the fixed core and movable core of the injector by 2nd Embodiment of this invention were expanded. It is sectional drawing to which the fixed core and movable core of the injector by 3rd Embodiment of this invention were expanded. It is sectional drawing to which the fixed core and movable core of the injector by 4th Embodiment of this invention were expanded. It is sectional drawing to which the fixed core and movable core of the injector by 5th Embodiment of this invention were expanded. It is sectional drawing to which the fixed core and movable core of the injector by 6th Embodiment of this invention were expanded.

Explanation of symbols

  10 injectors (fuel injection valves), 23 injection holes, 24 needles (valve members), 32 coils, 40, 140, 240 fixed cores, 42, 43, 141, 242 second inclined surfaces, 44 annular grooves (steps), 50, 150, 250 Movable core, 52, 55, 151, 252 First inclined surface, 56 Protruding part (step part), 60 Abutting part, 61 Clearance, 251 Taper part

Claims (7)

A valve member for opening and closing the nozzle hole;
A movable core that reciprocates in the axial direction together with the valve member and has a first inclined surface that is inclined with respect to a central axis at an end opposite to the nozzle hole;
The coil has a second inclined surface that is in contact with the first inclined surface at the end on the movable core side, forms a contact portion with the first inclined surface, and is substantially parallel to the first inclined surface A stationary core that generates a magnetic attractive force that attracts the movable core to the opposite side of the nozzle hole between the movable core by energization;
A fuel injection valve comprising:   2. The fuel injection valve according to claim 1, wherein the first inclined surface and the second inclined surface have a shorter distance from a central axis as the distance from the nozzle hole increases.   2. The fuel injection valve according to claim 1, wherein the first inclined surface and the second inclined surface have a shorter distance from a central axis as they approach the injection hole.   4. The fuel injection valve according to claim 1, wherein the first inclined surface and the second inclined surface are installed on inner peripheral sides of the movable core and the fixed core, respectively.   5. The fuel injection valve according to claim 4, wherein the movable core has the first inclined surface formed on an inner peripheral wall of a tapered portion that is recessed toward the injection hole.   4. The fuel injection valve according to claim 1, wherein the first inclined surface and the second inclined surface are installed at radially outer ends of the movable core and the fixed core, respectively. .   At least one of the movable core and the fixed core is a step that forms a gap between the fixed core or the movable core on the radially outer side or the radially inner side of the first inclined surface or the second inclined surface. The fuel injection valve according to claim 1, further comprising a portion.

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