JP2019196716A - Fuel injection device - Google Patents

Abstract

To provide a fuel injection device 90 for suppressing the wear of a needle 50, a fixed core 41, and a movable core.SOLUTION: The fuel injection device 90 includes a housing 30, the fixed core 41, a first movable core 42, a second movable core 43, a coil 44, the needle 50, and a spring 61. The first movable core is constructed to transmit force directed from the side of an injection hole 32 to the side of the fixed core in an axial direction AX to the second movable core, the second movable core is constructed to transmit force directed from the side of the injection hole to the side of the fixed core in the axial direction to the needle, at least one of the first movable core and the fixed core having a space 422 where the second movable core is movable along the axial direction together with the needle in the state that the first movable core contacts the fixed core in the axial direction.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a fuel injection device.

  For example, Patent Document 1 discloses a fuel injection valve that includes a needle that opens and closes a nozzle hole and a movable core that is provided separately from the needle valve. In this fuel injection valve, the needle valve moves in the valve opening direction together with the movable core that receives the magnetic attractive force from the fixed core. After the movable core contacts the fixed core, the needle valve moves away from the movable core due to inertia and further moves in the valve opening direction. Thereafter, the needle valve is pushed back by the spring, moves in the valve closing direction, and again contacts the movable core.

Japanese Patent Laid-Open No. 2006-65545

  In the fuel injection valve (fuel injection device) described above, when the needle is pushed back by the spring and comes into contact with the movable core, a large impact force may be generated, and the contact portion between the needle and the movable core may be worn. . Suppressing wear at the contact portion is an important issue regardless of whether the fuel injection device injects liquid fuel or the fuel injection device injects gaseous fuel. In particular, in a fuel injection device that injects gaseous fuel, compared to a fuel injection device that injects liquid fuel, the squeeze force caused by the fuel that the contact portion receives when the needle and the movable core come into contact with each other is small, and the impact force is large. Therefore, the problem described above becomes more prominent.

  This indication is realizable as the following forms.

  According to one form of the present disclosure, a fuel injection device (90, 90B, 90C, 90D) is provided. The fuel injection device includes a cylindrical housing (30) in which a nozzle hole (32) for injecting fuel and a first flow path (101) communicating with the nozzle hole are formed; fixed in the housing; A cylindrical fixed core (41) in which a second flow path (102) communicating with the first flow path is formed; and the axial direction of the housing in the first flow path closer to the nozzle hole than the fixed core A first movable core (42) provided so as to be reciprocally movable along (AX), having an outer diameter larger than an inner diameter of the fixed core and having a first through hole (421); the fixed core and the The first movable core is provided so as to be capable of reciprocating along the axial direction of the housing within the first flow path, has an outer diameter smaller than the outer diameter of the first movable core, and has a second penetration A second movable core (43) having a hole (431); A coil (44) for generating a magnetic field for moving the first movable core and the second movable core toward the fixed core; an axis passing through the first through hole and the second through hole in the axial direction; A needle (50, 50B) having a portion (51) and a valve portion (52) formed at an end of the shaft portion on the nozzle hole side and capable of opening and closing the nozzle hole; A spring (61) biasing toward the hole side. The first movable core is configured to be able to transmit a force from the nozzle hole side in the axial direction toward the fixed core side with respect to the second movable core; It is configured to be able to transmit a force from the nozzle hole side to the fixed core side in the axial direction; at least one of the first movable core and the fixed core is configured such that the first movable core is connected to the fixed core. The second movable core has a space (422, 423) that can move along the axial direction together with the needle while being in contact in a direction.

  According to the fuel injection device of this aspect, the second movable core can move along the axial direction together with the needle independently of the first movable core in a state where the first movable core is in contact with the fixed core in the axial direction. Therefore, the impact force when the second movable core and the fixed core collide with each other is reduced. Therefore, wear at the contact portion between the second movable core and the fixed core can be suppressed.

  The present disclosure can also be realized in various forms other than the fuel injection device. For example, it can be realized in the form of an injector or a fuel injection method.

Explanatory drawing which shows schematic structure of the fuel-injection apparatus in 1st Embodiment. The 1st explanatory view showing valve opening operation of the fuel injection device in a 1st embodiment. 2nd explanatory drawing which shows the valve opening operation | movement of the fuel-injection apparatus in 1st Embodiment. Explanatory drawing which shows the valve closing operation | movement of the fuel-injection apparatus in 1st Embodiment. The time chart which shows an example of the waveform of the drive current in a fuel-injection apparatus. Explanatory drawing which shows schematic structure of the fuel-injection apparatus in 2nd Embodiment. Explanatory drawing which shows the valve opening operation | movement of the fuel-injection apparatus in 2nd Embodiment. Explanatory drawing which shows schematic structure of the fuel-injection apparatus in 3rd Embodiment. Explanatory drawing which shows schematic structure of the fuel-injection apparatus in other embodiment.

A. First embodiment:
As shown in FIG. 1, the fuel injection device 90 of the first embodiment includes an injector 20 and a control unit 80. The fuel injection device 90 of the present embodiment injects hydrogen gas that is gaseous fuel by the injector 20. The injection of hydrogen gas from the injector 20 is controlled by the control unit 80. The injector 20 includes a housing 30, a fixed core 41, a first movable core 42, a second movable core 43, a coil 44, a needle 50, a first spring 61, and a second spring 62. .

  The housing 30 is a cylindrical member in which an injection hole 32 for injecting fuel and a first flow path 101 communicating with the injection hole 32 are formed. The housing 30 of the present embodiment includes, in order from the nozzle hole 32 side, the nozzle tip part 31 in which the nozzle holes 32 are formed, the first magnetic part 34, the nonmagnetic part 36, the second magnetic part 35, and the inlet part. 37. A valve seat 33 is provided around the nozzle hole 32 on the inner surface of the housing 30 of the nozzle tip portion 31. Between the nozzle tip part 31 and the first magnetic part 34, between the first magnetic part 34 and the nonmagnetic part 36, between the nonmagnetic part 36 and the second magnetic part 35, and between the second magnetic part 35 and the inlet part. 37 is welded at a welded portion 38. In the present embodiment, the nozzle tip portion 31 is made of martensitic stainless steel that is a nonmagnetic material. The first magnetic part 34 and the second magnetic part 35 are made of ferritic stainless steel, which is a magnetic material. The nonmagnetic portion 36 is formed of austenitic stainless steel that is a nonmagnetic material.

  A supply pipe (not shown) for supplying fuel to the injector 20 is connected to the inlet portion 37. The supply pipe is connected so as to contact a backup ring 72 provided at the inlet portion 37. A gap between the supply pipe and the inlet portion 37 is sealed by an O-ring 73 provided on the backup ring 72. An inlet channel 103 is formed in the inlet portion 37. A filter 71 is provided in the inlet channel 103. The filter 71 collects foreign matter contained in the fuel supplied from the supply pipe and suppresses the foreign matter from flowing into the housing 30.

  The fixed core 41 is a cylindrical member fixed in the housing 30. A second flow path 102 communicating with the first flow path 101 is formed in the fixed core 41. The opposite side of the second channel 102 from the first channel 101 communicates with the inlet channel 103. In the present embodiment, the fixed core 41 is made of a ferritic stainless steel that is a magnetic material.

  The first movable core 42 is a cylindrical member provided so as to be capable of reciprocating along the axial direction AX of the housing 30 in the first flow path 101 closer to the injection hole 32 than the fixed core 41. The first movable core 42 has an outer diameter that is larger than the inner diameter of the fixed core 41. The first movable core 42 has a first through hole 421 that is smaller than the inner diameter of the fixed core 41. The surface of the first movable core 42 on the fixed core 41 side has a first recess 422 around the first through hole 421. The first recess 422 is a circular depression formed on the surface of the first movable core 42 on the fixed core 41 side. The first movable core 42 and the fixed core 41 are configured to be contactable in the axial direction AX. In this embodiment, the 1st movable core 42 is formed with the ferritic stainless steel which is a magnetic material.

  The second movable core 43 is a cylindrical member provided so as to be capable of reciprocating along the axial direction AX in the first flow path 101 between the fixed core 41 and the first movable core 42. The second movable core 43 has an outer diameter that is larger than the inner diameter of the fixed core 41 and smaller than the diameter of the first recess 422 of the first movable core 42. The second movable core 43 has a second through hole 431 that is smaller than the inner diameter of the fixed core 41. The second movable core 43 and the fixed core 41 are configured to be contactable in the axial direction AX. The second movable core 43 is configured to be accommodated in the first recess 422 of the first movable core 42. In this embodiment, the 2nd movable core 43 is formed with the ferritic stainless steel which is a magnetic material.

  The coil 44 is wound around the outer periphery of the housing 30. The outer periphery of the coil 44 is covered with a yoke 45 formed of ferritic stainless steel, which is a magnetic material. The coil 44 generates a magnetic field that moves the first movable core 42 and the second movable core 43 toward the fixed core 41 when energized. The drive current for moving the first movable core 42 and the second movable core 43 is supplied to the coil 44 from a power supply source (not shown) such as a battery, for example. The drive current supplied from the power supply source to the coil 44 is controlled by, for example, a control unit 80 configured by an engine ECU or the like.

  The needle 50 includes a shaft portion 51, a valve portion 52, a stopper portion 53, and a flange portion 54. The shaft portion 51 is provided so as to be capable of reciprocating in the first through hole 421 along the axial direction AX. The central axis of the shaft portion 51 is the same as the central axis of the fixed core 41, the central axis of the first movable core 42, and the central axis of the second movable core 43. A communication channel 104 through which fuel flows from the second channel 102 toward the first channel 101 is formed inside the shaft portion 51.

  The valve portion 52 is formed at an end portion of the shaft portion 51 on the nozzle hole 32 side. The valve portion 52 is configured to be able to come into contact with a valve seat 33 provided in the nozzle tip portion 31, and is a valve body that opens and closes the injection hole 32 when the shaft portion 51 reciprocates along the axial direction AX. . The fuel that has flowed through the housing 30 in the order of the inlet channel 103, the second channel 102, the communication channel 104, and the first channel 101 is injected from the nozzle hole 32 when the nozzle hole 32 is opened. .

  The stopper portion 53 is a disk-shaped member located on the valve portion 52 side in the shaft portion 51. The stopper portion 53 is larger than the diameter of the first through hole 421 of the first movable core 42 and the diameter of the second through hole 431 of the second movable core 43 in the radial direction of the shaft portion 51, and the first movable core. It protrudes smaller than the diameter of the first concave portion 422 of 42. Therefore, the second movable core 43 is configured to be accommodated in the first recess 422 of the first movable core 42. In the present embodiment, the stopper portion 53 is formed of austenitic stainless steel, which is a nonmagnetic material, and is press-fitted into the shaft portion 51.

  The flange portion 54 is a disk-shaped member located on the fixed core 41 side in the shaft portion 51. The flange portion 54 protrudes in the radial direction of the shaft portion 51 larger than the diameter of the second through hole 431 of the second movable core 43 and smaller than the inner diameter of the fixed core 41. In the present embodiment, the shaft portion 51, the valve portion 52, and the flange portion 54 are integrally formed. The shaft portion 51, the valve portion 52, and the flange portion 54 are made of martensitic stainless steel, which is a nonmagnetic material.

  In the present embodiment, the second movable core 43 is welded to the flange portion 54 protruding from the shaft portion 51, and is further sandwiched between the flange portion 54 and the stopper portion 53 press-fitted into the shaft portion 51, so that the needle 50 is fixed. Therefore, the second movable core 43 can transmit a force from the nozzle hole 32 side to the fixed core 41 side in the axial direction AX with respect to the needle 50. In the present specification, the stopper portion 53 and the flange portion 54 may be referred to as a fixing portion.

  In the present embodiment, the first recess 422 provided in the first movable core 42 is configured to accommodate the second movable core 43 and the stopper portion 53, and the first movable core 42 is axially disposed on the fixed core 41. The second movable core 43 forms a space that can move along the axial direction AX together with the needle 50 while being in contact with each other at AX.

  The first spring 61 is disposed in the second flow path 102. The first spring 61 urges the flange portion 54 from the fixed core 41 side toward the injection hole 32 side. In the present embodiment, the first spring 61 is a coil spring. An adjusting pipe 63 is provided upstream of the first spring 61 in the second flow path 102. The force with which the first spring 61 pushes the flange portion 54 is configured to be adjustable by adjusting the position of the end portion of the adjusting pipe 63 on the injection hole 32 side.

  The second spring 62 is disposed in the first flow path 101 and biases the first movable core 42 from the nozzle hole 32 side toward the fixed core 41 side. The second spring 62 of the present embodiment is a coil spring. In the valve closed state, the first movable core 42 is pushed by the second spring 62, and the stopper portion 53 and the first movable core 42 come into contact with each other.

  The valve opening operation performed in the fuel injection device 90 of the present embodiment will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the valve portion 52 is in contact with the valve seat 33 in the valve closed state. In the closed state, the coil 44 is not energized. The flange portion 54 is pushed from the fixed core 41 side toward the nozzle hole 32 side by the first spring 61. The first movable core 42 is pushed by the second spring 62 from the nozzle hole 32 side toward the fixed core 41 side. Therefore, the first movable core 42 and the second movable core 43 are in contact with each other. In this specification, this state is also referred to as an initial state. In the initial state, a first interval d1 is secured between the surface of the first movable core 42 on the fixed core 41 side and the surface of the fixed core 41 on the injection hole 32 side in the axial direction AX. A second interval d2 is secured between the surface of the second movable core 43 on the fixed core 41 side and the surface of the first movable core 42 on the injection hole 32 side in the axial direction AX. The second interval d2 is longer than the first interval d1. The sum of the first interval d1 and the second interval d2 is the total lift amount L2 by which the needle 50 is lifted from the injection hole 32 side to the fixed core 41 side in the valve open state.

  As shown in FIG. 2, when energization of the coil 44 is started by the control unit 80, the first movable core 42 together with the second movable core 43 and the needle 50 are sprayed by the magnetic attractive force from the fixed core 41. The first movable core 42 collides with the fixed core 41 by moving from the 32 side toward the fixed core 41 side. The distance that the first movable core 42 moves while being accelerated by the magnetic attractive force from the fixed core 41 from the initial state until it collides with the fixed core 41 is the same as the first interval d1, and therefore the total lift amount Shorter than L2. Therefore, the speed of the first movable core 42 when colliding with the fixed core 41 is smaller than that in which the first movable core 42 moves the total lift amount L2 by the magnetic attraction force from the fixed core 41, and the first movable core 42 becomes smaller. The impact force when the core 42 and the fixed core 41 collide is reduced. Since the needle 50 moves the same distance as the first interval d1 together with the first movable core 42 from the initial state until the first movable core 42 collides with the fixed core 41, the needle 50 is fixed from the injection hole 32 side. The intermediate lift amount L1 that is the same as the first interval d1 is lifted toward the 41 side. Therefore, the valve part 52 moves away from the valve seat 33 and fuel injection from the injection hole 32 is started. In this specification, the state in which the needle 50 is moved from the nozzle hole 32 side toward the fixed core 41 side by the intermediate lift amount L1 from the initial state is also referred to as a first valve opening state. As the needle 50 moves, the first spring 61 is pushed by the flange portion 54 and contracts, so that elastic energy is stored in the first spring 61.

  As shown in FIG. 3, after the first movable core 42 collides with the fixed core 41, the second movable core 43 together with the needle 50 moves from the nozzle hole 32 side to the fixed core 41 side by the magnetic attractive force from the fixed core 41. Further, the second movable core 43 collides with the fixed core 41. Since the second movable core 43 and the needle 50 are configured to be movable independently of the first movable core 42 from the first valve opening state to the collision with the fixed core 41, The impact force when the fixed core 41 collides is reduced. Since the needle 50 moves the same distance as the second interval d2 together with the second movable core 43 from the first valve opening state until the second movable core 43 collides with the fixed core 41, the needle 50 is moved from the initial state, The total lift amount L2 that is the same as the sum of the first interval d1 and the second interval d2 is lifted from the nozzle hole 32 side toward the fixed core 41 side. Therefore, the fuel injected from the injection hole 32 increases as the valve portion 52 further moves away from the valve seat 33. In this specification, the state in which the needle 50 is moved from the injection hole 32 side toward the fixed core 41 side by the total lift amount L2 from the initial state is also referred to as a second valve opening state. In this specification, the distance that the first movable core 42 moves toward the fixed core 41 may be referred to as a first distance, and the first movable core 42 contacts the fixed core 41 in the axial direction AX. In this state, the distance that the second movable core 43 moves toward the fixed core 41 may be referred to as a second distance. The second movable core 43 is stopped while being in contact with the fixed core 41 by the magnetic attractive force from the fixed core 41, and the second valve open state is maintained. The valve opening operation in the fuel injection device 90 is completed by the series of operations described above.

  The valve closing operation performed in the fuel injection device 90 of the present embodiment will be described with reference to FIG. As shown in FIG. 4, when energization of the coil 44 is stopped by the control unit 80, the magnetic attraction force from the fixed core 41 is unloaded, and the needle 50 biased by the first spring 61 is the first. The valve portion 52 and the valve seat 33 collide with the movable core 42 and the second movable core 43 moving from the fixed core 41 side toward the injection hole 32 side. Therefore, the valve is closed and the fuel injection from the nozzle hole 32 is stopped. After the valve portion 52 and the valve seat 33 collide, the first movable core 42 is configured to be further movable from the fixed core 41 side toward the injection hole 32 side by inertia. Therefore, the impact force when the valve part 52 and the valve seat 33 collide is reduced. Thereafter, the first movable core 42 is supported by the second spring 62 and returns to the initial state. The valve closing operation in the fuel injection device 90 is completed by the series of operations described above.

  FIG. 5 shows an example of the waveform of the drive current supplied from the control unit 80 to the coil 44 on the time chart. In order from the top in FIG. 5, the drive current I represents the current flowing through the coil 44. The magnetic attractive force F represents the magnetic attractive force generated by the fixed core 41 when the drive current I flows through the coil 44. The displacement X represents the displacement in the axial direction AX of the first movable core 42 from the initial state. The displacement Y represents the displacement in the axial direction AX of the second movable core 43 from the initial state. The fuel injection rate R represents the fuel injection amount per unit time in the injector 20.

  Between timing t0 and timing t1, the controller 80 does not supply the driving current I to the coil 44 (driving current I0). Therefore, no magnetic attractive force F is generated from the fixed core 41 (magnetic attractive force F0), and the displacement X of the first movable core 42 and the displacement Y of the second movable core 43 remain in the initial state. (Displacement X0, displacement Y0), fuel is not injected (fuel injection rate R0).

  Between timing t1 and timing t2, the control unit 80 first supplies a large drive current I1 to the coil 44. In the present specification, the drive current I1 may be referred to as a first current. A large magnetic attractive force F1 from the fixed core 41 is generated by the drive current I1. The first movable core 42 and the second movable core 43 move together by the magnetic attractive force F1, the first movable core 42 becomes the displacement X1, and the second movable core 43 becomes the displacement Y1. The displacement X1 of the first movable core 42 and the displacement Y1 of the second movable core 43 are both the same as the intermediate lift amount L1. Therefore, the needle 50 is lifted by the intermediate lift amount L1, and the fuel injection rate R1 corresponding to the intermediate lift amount L1 is obtained. After reaching the fuel injection rate R1, the control unit 80 supplies a drive current I2 smaller than the drive current I1 to the coil 44. A magnetic attraction force F2 smaller than the magnetic attraction force F1 is generated by the drive current I2. In order to separate the valve part 52 from the valve seat 33, a large magnetic attractive force F1 corresponding to the force of the first spring 61 and the force of the fuel pressure is required. On the other hand, after the valve portion 52 is separated from the valve seat 33, if there is a magnetic attractive force F2 corresponding to the force by the first spring 61, the displacement X1 of the first movable core 42 and the displacement Y1 of the second movable core 43 are provided. Can be displaced according to the intermediate lift amount L1, and the fuel injection rate R1 can be secured. Therefore, power saving can be achieved by reducing the drive current I supplied to the coil 44 by the control unit 80.

  Between timing t2 and timing t3, the control unit 80 supplies the coil 44 with a driving current I3 that is larger than the driving current I2 and smaller than the driving current I1. In the present specification, the drive current I3 may be referred to as a second current. The drive current I3 generates a magnetic attractive force F3 that is larger than the magnetic attractive force F2 and smaller than the magnetic attractive force F1. Since the first movable core 42 is in contact with the fixed core 41 in the axial direction AX, the displacement of the first movable core 42 remains the displacement X1. On the other hand, the second movable core 43 further moves independently of the first movable core 42, and the displacement of the second movable core 43 becomes a displacement Y2 larger than the displacement Y1. At this time, the second movable core 43 collides with the fixed core 41 because the second movable core 43 moves from the injection hole 32 side toward the fixed core 41 side by the magnetic attractive force F3 smaller than the magnetic attractive force F1. Speed is reduced. Therefore, the impact force when the second movable core 43 collides with the fixed core 41 is reduced. The displacement Y2 of the second movable core 43 is the same as the total lift amount L2. Therefore, the needle 50 is lifted by the total lift amount L2, and the fuel injection rate R2 corresponding to the total lift amount L2 is obtained.

  After timing t3, the control unit 80 supplies the drive current I4 in the opposite direction to the drive current I3 to the coil 44, and then stops supplying the drive current. By supplying the drive current I4, the magnetic attractive force F from the fixed core 41 is unloaded with good response. When the magnetic attractive force F is unloaded, the needle 50 is pushed back to the first spring 61. When the needle 50 is pushed back, the displacement X of the first movable core 42 and the displacement Y of the second movable core 43 return to the initial state, and the fuel injection is stopped.

  According to the fuel injection device 90 of the present embodiment described above, the distance that the first movable core 42 moves from the initial state until it collides with the fixed core 41 is such that the second movable core 43 is fixed from the initial state. It is shorter than the distance traveled before colliding with the core 41. Therefore, by suppressing the acceleration of the first movable core 42, the speed of the first movable core 42 when colliding with the fixed core 41 is reduced, and when the first movable core 42 and the fixed core 41 collide with each other. The impact force is reduced. Further, since the needle 50 and the second movable core 43 move independently from the first movable core 42 from the first valve opening state until the collision with the fixed core 41, the second movable core 43 and the fixed core 41 are moved. The impact force when the two collide with each other is reduced. Therefore, wear at the contact portion between the first movable core 42 and the fixed core 41 and at the contact portion between the second movable core 43 and the fixed core 41 can be suppressed.

  In particular, as in the present embodiment, when the fuel injection device 90 is in the form of injecting gaseous fuel, the contact portion between the first movable core 42 and the fixed core 41, as compared with the form of injecting liquid fuel, the second Since the squeeze force by the fuel when the contact portion between the movable core 43 and the fixed core 41 and the contact portion between the stopper portion 53 and the first movable core 42 collide is small, the impact force at each contact portion increases. Therefore, the effect of suppressing wear of each contact portion is great.

  In the present embodiment, after the first movable core 42 collides with the fixed core 41, the magnetic attraction force from the fixed core 41 is reduced by reducing the drive current supplied to the coil 44 by the control unit 80. Therefore, the speed when the second movable core 43 collides with the fixed core 41 is reduced, and the impact force when the second movable core 43 and the fixed core 41 collide can be further reduced. In particular, from the state in which the first movable core 42 is in contact with the fixed core 41 in the axial direction AX than the first distance in which the first movable core 42 moves toward the fixed core 41 as in the present embodiment, When the second distance in which the two movable cores 43 move toward the fixed core 41 is longer, the distance that the second movable core 43 is accelerated by the magnetic attractive force from the fixed core 41 becomes longer. By reducing the drive current supplied to the coil 44, the effect of reducing the impact is great.

  In the present embodiment, the fuel injection rate can be adjusted in multiple stages by adjusting the drive current supplied from the control unit 80 to the coil 44 in accordance with the required combustion injection rate.

B. Second embodiment:
As shown in FIG. 6, in the fuel injection device 90B of the second embodiment, the configuration of the injector 20B is different from that of the first embodiment. Specifically, the second movable core 43 and the needle 50B are not fixed, and the second movable core 43 contacts the flange portion 54 in the axial direction AX, so that the needle 50B is in the axial direction AX. It is configured to be able to transmit a force from the nozzle hole 32 side toward the fixed core 41 side. Therefore, the shaft portion 51 of the needle 50B can reciprocate in the second through hole 431 along the axial direction AX. Moreover, the stopper part 53 is not provided in the needle 50B. The surface of the second movable core 43 on the nozzle hole 32 side is subjected to DLC coating, so that the second movable core 43 that has received the magnetic attractive force from the fixed core 41 is easily separated from the first movable core 42. Yes. Other configurations are the same as those of the first embodiment. In addition, in this specification, the flange part 54 may be called a protrusion part.

  The valve opening operation in the fuel injection device 90B of the second embodiment will be described. The valve opening operation until the second movable core 43 collides with the fixed core 41 is the same as in the first embodiment. As shown in FIG. 7, after the second movable core 43 collides with the fixed core 41, the needle 50 further moves from the injection hole 32 side toward the fixed core 41 side due to inertia and is pushed back by the first spring 61. As a result, the second movable core 43 collides again. Thereafter, the needle 50 is supported by the second movable core 43, whereby the total lift amount L2 is ensured.

  According to the fuel injection device 90B of this embodiment, the impact force when the first movable core 42 collides with the fixed core 41 is reduced by the second movable core 43 and the needle 50 being detached from the first movable core 42. The Further, the impact force when the second movable core 43 collides with the fixed core 41 is reduced by the needle 50 being detached from the second movable core 43. Therefore, wear at the contact portion between the first movable core 42 and the fixed core 41, the contact portion between the second movable core 43 and the fixed core 41, and the contact portion between the needle 50 and the second movable core 43 can be suppressed.

  In the present embodiment, after the first movable core 42 collides with the fixed core 41, the second movable core 43 collides with the fixed core 41 by reducing the drive current supplied to the coil 44 by the control unit 80. Speed is reduced. By reducing the speed at which the second movable core 43 collides with the fixed core 41, the elastic energy stored in the first spring 61 is reduced. Therefore, it is possible to further reduce the impact force when the second movable core 43 and the fixed core 41 collide and the impact force when the needle 50 and the second movable core 43 collide.

C. Third embodiment:
As shown in FIG. 8, in the fuel injection device 90C of the third embodiment, the liquid fuel is injected by the injector 20C, which is different from the first embodiment. Examples of the liquid fuel include gasoline and light oil. Further, the nozzle tip portion 31C is different from the first embodiment in that a plurality of injection holes 32 are provided. Other configurations and opening / closing operations are the same as those in the first embodiment.

  According to the fuel injection device 90C of this embodiment, since the injector 20C is configured to inject liquid fuel, the contact portion between the first movable core 42 and the fixed core 41 compared to the configuration in which the injector 20C injects gaseous fuel. The squeeze force due to the fuel when the contact portion between the second movable core 43 and the fixed core 41 and the contact portion between the stopper portion 53 and the first movable core 42 collide is increased, and the impact force at each contact portion is increased. Get smaller.

D. Other embodiments:
(D-1) In the fuel injection device 90 in each embodiment described above, the first concave portion 422 provided on the surface of the first movable core 42 on the fixed core 41 side is provided, and the second movable core 43 and the stopper portion 53 are provided. Since the first movable core 42 is in contact with the fixed core 41 in the axial direction AX, the second movable core 43 moves along with the needle 50 along the axial direction AX. A possible space is formed. In contrast to this, as in the fuel injection device 90D shown in FIG. You may be comprised so that accommodation is possible. Even in this configuration, a space in which the second movable core 43 can move along the axial direction AX together with the needle 50 is formed with the first movable core 42 in contact with the fixed core 41 in the axial direction AX.

(D-2) In the fuel injection device 90 in each of the above-described embodiments, the control unit 80 causes the first current (drive current I1) after the first movable core 42 collides with the fixed core 41 with respect to the coil 44. A smaller second current (drive current I3) is supplied. On the other hand, the control unit 80 may supply the first current (drive current I1) to the coil 44 even after the first movable core 42 collides with the fixed core 41.

(D-3) In the fuel injection device 90 in the first embodiment and the fuel injection device 90C in the third embodiment described above, the second movable core 43 is sandwiched between the flange portion 54 and the stopper portion 53. The needle 50 is fixed. On the other hand, the second movable core 43 may be fixed to the needle 50 by being welded to the shaft portion 51 or the like instead of being fixed by being sandwiched between the flange portion 54 and the stopper portion 53.

(D-4) In the fuel injection device 90 in each of the above-described embodiments, the first movable core 42 is axially directed to the fixed core 41 rather than the first distance in which the first movable core 42 moves toward the fixed core 41 side. The second distance by which the second movable core 43 moves toward the fixed core 41 side from the state of contact in AX is longer. On the other hand, the first distance may be equal to or less than the second distance.

  The present disclosure is not limited to the above-described embodiment, and can be realized with various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments are appropriately replaced or combined to solve part or all of the above-described problems or to achieve part or all of the above-described effects. Is possible. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

20, 20B, 20C injector, 30 housing, 31, 31C nozzle tip part, 32 nozzle hole, 33 valve seat, 34 first magnetic part, 35 second magnetic part, 36 nonmagnetic part, 37 inlet part, 38 welded part, 41 fixed core, 42 first movable core, 43 second movable core, 44 coil, 45 yoke, 50, 50B needle, 51 shaft portion, 52 valve portion, 53 stopper portion, 54 flange portion, 61 first spring, 62 first 2 spring, 63 adjusting pipe, 71 filter, 72 backup ring, 73 O-ring, 80 control unit, 90, 90B, 90C, 90D fuel injection device, 101 first flow path, 102 second flow path, 103 inlet flow path 104 communication channel, 421 first through hole, 422 first recess, 423 second recess, 431 second penetration , AX axis, d1 first distance, d2 a second distance, L1 intermediate lift, L2 total lift.

Claims (6)

A fuel injection device (90, 90B, 90C, 90D),
A cylindrical housing (30) in which a nozzle hole (32) for injecting fuel and a first flow path (101) communicating with the nozzle hole are formed;
A cylindrical fixed core (41) fixed in the housing and formed with a second channel (102) communicating with the first channel;
It is provided so as to be capable of reciprocating along the axial direction (AX) of the housing in the first flow path on the nozzle hole side of the fixed core, and has an outer diameter larger than the inner diameter of the fixed core, A first movable core (42) having one through hole (421);
A reciprocating movement is provided in the first flow path between the fixed core and the first movable core along the axial direction of the housing, and has an outer diameter smaller than the outer diameter of the first movable core. A second movable core (43) having a second through hole (431),
A coil (44) for generating a magnetic field for moving the first movable core and the second movable core toward the fixed core by energization;
A shaft portion (51) that passes through the first through hole and the second through hole in the axial direction, and a valve portion (52) that is formed at an end portion of the shaft portion on the nozzle hole side and that can open and close the nozzle hole. And a needle (50, 50B) having
A spring (61) for urging the needle toward the nozzle hole;
With
The first movable core is configured to be able to transmit a force from the nozzle hole side toward the fixed core side in the axial direction with respect to the second movable core,
The second movable core is configured to be able to transmit a force from the nozzle hole side in the axial direction toward the fixed core side with respect to the needle.
At least one of the first movable core and the fixed core is such that the second movable core moves along the axial direction together with the needle while the first movable core is in contact with the fixed core in the axial direction. With possible spaces (422, 423),
Fuel injection device. The fuel injection device according to claim 1,
A fixed portion (53, 54) to which the needle and the second movable core are fixed;
The second movable core is a fuel injection device that transmits a force from the injection hole side in the axial direction toward the fixed core side to the needle via the fixed portion. The fuel injection device according to claim 1,
The shaft portion has a protruding portion (54) that protrudes larger in the radial direction than the diameter of the second through hole on the fixed core side with respect to the second movable core,
The second movable core is a fuel injection device that transmits a force from the nozzle hole side to the fixed core side in the axial direction to the needle by contacting the protruding portion in the axial direction. The fuel injection device according to any one of claims 1 to 3,
From the state in which the first movable core is in contact with the fixed core in the axial direction than the first distance in which the first movable core moves toward the fixed core by the energization, the second movable core is The fuel injection device, wherein the second distance moved toward the fixed core side by energization is longer. The fuel injection device according to any one of claims 1 to 4,
A fuel injection device for injecting gas as the fuel. The fuel injection device according to any one of claims 1 to 5,
And a control unit (80) for controlling the energization of the coil,
The controller supplies the coil with a first current that moves the first movable core and the second movable core from the nozzle hole side toward the fixed core side, and then the first current Supplying a smaller second current,
Fuel injection device.

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