JP2021105350A - Fuel injection valve - Google Patents

Abstract

To suppress deterioration of an impact reduction effect caused by a damper chamber.SOLUTION: A fuel injection valve 100 includes a housing 20, a fixed core 60, a movable core 50, a needle 40 and a coil 70. The housing includes: a first inner surface 121 on which the needle slides in a longitudinal direction Z; a second inner surface 122 on which the movable core slides in the longitudinal direction; and a third inner surface 123 to which the fixed core is fixed. A step surface 124 is provided between the first inner surface and the second inner surface. A damper chamber 25 in which fuel is sealed is defined by the second inner surface, the step surface, the needle and the movable core, and the second inner surface is provided on the inner side in the radial direction of the third inner surface.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a fuel injection valve.

Patent Document 1 describes a fuel injection valve having a damper chamber surrounded by a housing and a movable core. In this fuel injection valve, the movable core is decelerated by using the pressure change of the fuel in the damper chamber due to the movement of the movable core, so that the impact due to the collision between the movable core and the fixed core at the time of valve opening and the needle at the time of valve closing The impact caused by the collision between the valve seat and the valve seat is reduced.

JP-A-2018-189002

In a fuel injection valve, for example, when fuel is supplied from the outside or when it is mounted on an engine or the like, an axial force along the longitudinal direction may act on a portion of the housing to which a fixed core is fixed. be. In this case, strain may occur in the sliding portion of the housing where the movable core slides, and the size of the gap between the portion and the movable core may change. Therefore, the pressure change for decelerating the movable core with respect to the fuel in the damper chamber cannot be generated as intended, and the impact reduction effect of the damper chamber may be reduced.

The present disclosure can be realized in the following forms.

According to the first aspect of the present disclosure, a fuel injection valve (100, 100c) is provided. This fuel injection valve has a longitudinal direction (Z), and has a tubular housing (20, 20c) provided with an injection hole (31) for injecting fuel at one end in the longitudinal direction, and the inside of the housing. With the movement of the fixed core (60) fixed to the fixed core, the movable core (50) arranged on one end side of the fixed core and movable in the housing along the longitudinal direction, and the movable core. A needle (40) for opening and closing the injection hole by moving in the housing along the longitudinal direction, and a coil (70) for generating a magnetic field for moving the movable core are provided. The housing is provided in order from the one end side, on the first inner side surface (121) on which the needle slides along the longitudinal direction, and on the outer side in the radial direction where the needle intersects the first inner side surface in the longitudinal direction. The movable core has a second inner surface surface (122, 122c) that slides along the longitudinal direction, and a third inner surface surface (123) to which the fixed core is fixed. It has a stepped surface (124,126) provided between the first inner surface and the second inner surface, and the fuel is provided by the second inner surface, the stepped surface, the needle, and the movable core. The damper chambers (25, 25c) in which the fuel is sealed are partitioned, and the second inner side surface is provided inside the third inner side surface in the radial direction.

According to the fuel injection valve of this form, the housing is provided with a second inner surface on which the movable core slides in the radial direction with respect to the third inner surface on which the fixed core is fixed. It is possible to suppress a change in the size of the gap between the second inner surface and the movable core when an axial force along the longitudinal direction acts on the inner surface. Therefore, it is possible to suppress a decrease in the impact reduction effect of the damper chamber.

According to the second aspect of the present disclosure, a fuel injection valve (100b) is provided. This fuel injection valve has a longitudinal direction (Z), and is fixed in the tubular housing (20b) provided with a injection hole (31) for injecting fuel at one end in the longitudinal direction. For the movement of the cylindrical fixed core (60b), the movable core (50) arranged on one end side of the fixed core and movable in the housing along the longitudinal direction, and the movable core. Along with this, a needle (40b) that opens and closes the injection hole by moving in the housing along the longitudinal direction, and a coil (70) that generates a magnetic field that moves the movable core are provided. The needles are, in order from the one end side, a shaft portion (41) provided along the longitudinal direction, a diameter-expanded portion (43) having an outer diameter larger than the outer diameter of the shaft portion, and the longitudinal direction. The fixed core has an extension portion (46) having an outer diameter smaller than the outer diameter of the enlarged diameter portion, and the fixed core is an inner surface surface of a first core on which the enlarged diameter portion slides. 161), a second core inner surface (162) having an inner diameter smaller than the inner diameter of the first core inner surface and to which the extension portion slides, and the first core inner surface and the said in the fixed core. It has a core stepped surface (163) provided between the inner side surface of the second core, and the fuel is filled by the enlarged diameter portion, the extension portion, the inner surface surface of the first core, and the stepped surface of the core. The damper room (25b) to be used is partitioned.

According to this type of fuel injection valve, since the damper chamber is provided inside the fixed core, when an axial force along the longitudinal direction acts on the housing, the diameter-expanded portion of the needle and the first fixed core It is possible to suppress changes in the size of the gap between the inner surface of the core and the size of the gap between the extension of the needle and the inner surface of the second core of the fixed core. Therefore, it is possible to suppress a decrease in the impact reduction effect of the damper chamber.

The first explanatory view which shows the schematic structure of the fuel injection valve of 1st Embodiment. A partially enlarged view of part A in FIG. The second explanatory view which shows the schematic structure of the fuel injection valve of 1st Embodiment. The explanatory view which shows the schematic structure of the fuel injection valve of 2nd Embodiment. FIG. 4 is a partially enlarged view of part B in FIG. The explanatory view which shows the schematic structure of the fuel injection valve of 3rd Embodiment. FIG. 6 is a partially enlarged view of part C in FIG.

A. First Embodiment:
As shown in FIG. 1, the fuel injection valve 100 in the first embodiment includes a housing 20, a needle 40, a movable core 50, a fixed core 60, a coil 70, a first urging member 81, and a second. It includes an urging member 82. In FIG. 1, arrows along the X, Y, and Z directions orthogonal to each other are shown. In other figures as well, arrows along the X, Y, and Z directions are appropriately represented. The X, Y, Z directions in FIG. 1 and the X, Y, Z directions in other figures represent the same direction. The fuel injection valve 100 injects fuel. In the present embodiment, the fuel injection valve 100 injects hydrogen gas, which is a gaseous fuel. The fuel injection valve 100 may inject a gaseous fuel such as coal gas, acetylene gas, propane gas, or natural gas instead of hydrogen gas. The fuel injection valve 100 may inject a liquid fuel such as gasoline or light oil instead of the gaseous fuel.

The housing 20 has a longitudinal direction along the Z direction. In the housing 20, the injection nozzle 30, the first cylinder member 21, the second cylinder member 22, the third cylinder member 23, and the fourth cylinder member 24 are connected in this order toward the + Z direction side. It is configured. The injection nozzle 30 and the tubular members 21 to 24 each have a cylindrical shape centered on the central axis CL along the Z direction. An injection hole 31 for injecting fuel is provided at the end of the injection nozzle 30 on the −Z direction side. A valve seat 32 with which the valve portion 42 of the needle 40 comes into contact is provided on the peripheral edge of the injection hole 31 of the injection nozzle 30. In the present embodiment, between the injection nozzle 30 and the first cylinder member 21, between the first cylinder member 21 and the second cylinder member 22, and between the second cylinder member 22 and the third cylinder member 23. , The third cylinder member 23 and the fourth cylinder member 24 are fixed to each other by welding, press fitting, or the like, respectively. The injection nozzle 30 and the first cylinder member 21 are made of martensitic stainless steel, which is a metal material, and are hardened so as to have a predetermined hardness. The second cylinder member 22 and the fourth cylinder member 24 are made of ferritic stainless steel, which is a magnetic material. The third tubular member 23 is made of austenitic stainless steel, which is a non-magnetic material.

A fuel introduction pipe 12 is connected to the fourth cylinder member 24. In the present embodiment, the fourth cylinder member 24 and the fuel introduction pipe 12 are fixed to each other by welding. The fuel introduction pipe 12 has a cylindrical shape centered on the central axis CL. An introduction port 14 for introducing fuel is provided at the end of the fuel introduction pipe 12 on the + Z direction side. A supply pipe for supplying fuel to the fuel injection valve 100 is connected to the fuel introduction pipe 12. A backup ring 91 is provided on the outer peripheral portion of the fuel introduction pipe 12. The fuel introduction pipe 12 and the supply pipe are sealed by an O-ring 92 provided on the surface of the backup ring 91 on the + Z direction side. A filter 13 is provided in the fuel introduction pipe 12. The filter 13 collects foreign matter mixed in the fuel that has flowed in from the introduction port 14 and suppresses the foreign matter from flowing into the housing 20.

The needle 40 is movably arranged in the housing 20 along the central axis CL. The needle 40 has a shaft portion 41, a valve portion 42, and a diameter-expanded portion 43. The shaft portion 41 has a cylindrical shape centered on the central axis CL. The valve portion 42 is provided at the end portion of the shaft portion 41 on the −Z direction side. The injection hole 31 is closed when the valve portion 42 comes into contact with the valve seat 32, and the injection hole 31 is opened when the valve portion 42 is separated from the valve seat 32. In the present embodiment, the enlarged diameter portion 43 is provided at the end portion of the shaft portion 41 on the + Z direction side. The outer diameter of the enlarged diameter portion 43 is larger than the outer diameter of the shaft portion 41. The enlarged diameter portion 43 comes into contact with the end face of the movable core 50 on the + Z direction side. Inside the shaft portion 41 and the diameter-expanded portion 43, a fuel passage 44 through which fuel flows along the central shaft CL is provided. The fuel passage 44 has an opening on the end surface of the enlarged diameter portion 43 on the + Z direction side. A communication hole 45 communicating with the fuel passage 44 is provided on the side surface of the shaft portion 41.

The movable core 50 is movably arranged in the housing 20 along the central axis CL. The movable core 50 has a cylindrical shape centered on the central axis CL. The shaft portion 41 penetrates the inside of the movable core 50, and the shaft portion 41 slides on the inner wall surface of the movable core 50 along the Z direction. Sliding is not only that one object slides on the surface of the other object when the two objects are in contact with each other, but also that the fluid is interposed between the two objects that are close to each other. It also means that an object slides on the surface of the other object. The movable core 50 has a large diameter portion 56 and a small diameter portion 57. The outer diameter of the large diameter portion 56 is larger than the outer diameter of the small diameter portion 57. The small diameter portion 57 is provided so as to project from the large diameter portion 56 toward the −Z direction side. The enlarged diameter portion 43 comes into contact with the end face of the large diameter portion 56 on the + Z direction side.

In the present embodiment, the movable core 50 is composed of a first movable core member 51 formed of a magnetic material and a second movable core member 52 having a hardness higher than the hardness of the first movable core member 51. .. The hardness of the first movable core member 51 and the hardness of the second movable core member 52 can be examined by a Vickers hardness test (JIS Z 2244). The main body of the movable core 50 is composed of a first movable core member 51. The portion of the movable core 50 that contacts or slides on the housing 20, the portion that the needle 40 contacts or slides on, and the portion that contacts the fixed core 60 are composed of a second movable core member 52. .. In the present embodiment, the first movable core member 51 is made of ferritic stainless steel, which is a magnetic material. The second movable core member 52 is made of martensitic stainless steel, which is a metal material, and is hardened so as to have a predetermined hardness. The first movable core member 51 and the second movable core member 52 are fixed to each other by press fitting, welding, or the like.

The fixed core 60 is fixed to the + Z direction side of the movable core 50 in the housing 20. In the present embodiment, the fixed core 60 is fixed to the fourth cylinder member 24 by welding or the like. The fixed core 60 has a cylindrical shape centered on the central axis CL. The enlarged diameter portion 43 of the needle 40 slides on the inner wall surface of the fixed core 60. The movable core 50 that moves along the central axis CL comes into contact with the end face of the fixed core 60 on the −Z direction side. An adjusting pipe 11 having a cylindrical shape centered on the central axis CL is fixed to the portion on the + Z direction side inside the fixed core 60 by press fitting.

In the present embodiment, the fixed core 60 is composed of a first fixed core member 61 formed of a magnetic material and a second fixed core member 62 having a hardness higher than the hardness of the first fixed core member 61. .. The hardness of the first fixed core member 61 and the hardness of the second fixed core member 62 can be examined by a Vickers hardness test (JIS Z 2244). The main body portion of the fixed core 60 facing the first movable core member 51 is composed of the first fixed core member 61. The portion of the fixed core 60 on which the enlarged diameter portion 43 slides is composed of the second fixed core member 62. In the present embodiment, the first fixed core member 61 is made of ferritic stainless steel, which is a magnetic material. The second fixed core member 62 is made of martensitic stainless steel, which is a metal material, and is subjected to a quenching treatment so as to have a predetermined hardness. The first fixed core member 61 and the second fixed core member 62 are fixed to each other by press fitting.

The first urging member 81 is arranged between the adjusting pipe 11 and the diameter-expanded portion 43 inside the fixed core 60. The first urging member 81 urges the needle 40 toward the −Z direction side. In the present embodiment, the first urging member 81 is composed of a coil spring that expands and contracts along the Z direction. The end of the first urging member 81 on the + Z direction side is in contact with the adjusting pipe 11, and the end of the first urging member 81 on the −Z direction side is in contact with the enlarged diameter portion 43. .. By adjusting the position of the adjusting pipe 11 in the Z direction, the force with which the first urging member 81 urges the needle 40 can be adjusted. In the present embodiment, the adjusting pipe is such that the force of the first urging member 81 for urging the needle 40 is larger than the force for urging the movable core 50 by the second urging member 82, which will be described later. The position of 11 is adjusted.

The second urging member 82 is arranged between the first cylinder member 21 and the large diameter portion 56. The second urging member 82 urges the movable core 50 toward the + Z direction side. In the present embodiment, the second urging member 82 is composed of a coil spring that expands and contracts along the Z direction. The end of the second urging member 82 on the −Z direction side is in contact with the first cylinder member 21, and the end of the second urging member 82 on the + Z direction is in contact with the large diameter portion 56. There is.

A bobbin 71 around which the coil 70 is wound is arranged on the outer wall surface of the housing 20. In the present embodiment, the bobbin 71 is arranged so as to straddle the outer wall surface of the third cylinder member 23 and the outer wall surface of the fourth cylinder member 24. A portion of the outer wall surface of the fourth cylinder member 24 where the bobbin 71 is not arranged and a part of the outer wall surface of the fuel introduction pipe 12 are covered with a resin material. A connector 15 is provided on the side of the fourth cylinder member 24 so as to protrude from the outer wall surface of the fourth cylinder member 24. The connector 15 is provided with a terminal 16 electrically connected to the coil 70. In the present embodiment, the metal terminal 16 is provided on the resin connector 15 by insert molding. A power source such as a battery is electrically connected to the terminal 16 via a switching element or the like.

The coil 70 generates a magnetic field by receiving a current supply from a power source. The magnetic field generated by the coil 70 forms a magnetic circuit that passes through the second cylinder member 22, the first fixed core member 61, the first movable core member 51, and the fourth cylinder member 24. Therefore, a magnetic attraction force is generated between the movable core 50 and the fixed core 60. A tubular holder 17 is provided on the outer periphery of the coil 70 so as to cover the coil 70. An annular cover 18 is provided between the fourth tubular member 24 and the holder 17. The holder 17 and the cover 18 are each made of a magnetic material and form a part of the above-mentioned magnetic circuit.

As shown in FIG. 2, the housing 20 has a first inner side surface 121, a second inner side surface 122, and a third inner side surface 123 in this order from the −Z direction side. In the present embodiment, the first inner side surface 121 and the second inner side surface 122 are provided on the first cylinder member 21. The third inner side surface 123 is provided so as to straddle the first cylinder member 21, the second cylinder member 22, the third cylinder member 23, and the fourth cylinder member 24. The shaft portion 41 of the needle 40 slides along the Z direction on the first inner side surface 121, and the small diameter portion 57 of the movable core 50 slides on the second inner side surface 122 along the Z direction. A fixed core 60 is fixed to the third inner surface 123. A large diameter portion 56 of the movable core 50 is movably arranged on the −Z direction side of the fixed core 60 in the third inner side surface 123. The first inner surface 121, the second inner surface 122, and the third inner surface 123 each have a cylindrical shape centered on the central axis CL. The inner diameter of the second inner surface 122 is larger than the inner diameter of the first inner surface 121. The inner diameter of the third inner surface 123 is larger than the inner diameter of the second inner surface 122. A first stepped surface 124 that connects the first inner surface 121 and the second inner surface 122 is provided between the first inner surface 121 and the second inner surface 122 in the housing 20. A second stepped surface 125 connecting the second inner surface 122 and the third inner surface 123 is provided between the second inner surface 122 and the third inner surface 123 in the housing 20. The first stepped surface 124 and the second stepped surface 125 have an annular shape centered on the central axis CL. The state in which the fuel injection valve 100 is mounted on the mounting object OB such as an engine is referred to as a mounted state. The fuel injection valve 100 has a support surface 90 that is supported by the mounting object OB from the −Z direction side in the mounted state. In this embodiment, the support surface 90 is provided on the outer surface of the holder 17. The first inner side surface 121 and the second inner side surface 122 are provided on the −Z direction side with respect to the support surface 90.

Inside the housing 20, a damper chamber 25 is provided which is partitioned by a second inner side surface 122, a first stepped surface 124, a shaft portion 41, and a small diameter portion 57. Fuel is sealed in the damper chamber 25. Encapsulation of fuel does not mean that the fuel is completely contained, but that the fuel is contained to the extent that the free entry and exit of the fuel is restricted. The damper chamber 25 has a gap between the first inner side surface 121 and the shaft portion 41, a gap between the second inner side surface 122 and the small diameter portion 57, and a gap between the shaft portion 41 and the inner wall surface of the movable core 50. It communicates with the outside of the damper chamber 25 through the gap between the two. In the present embodiment, there is a gap between the first inner side surface 121 and the shaft portion 41, a gap between the second inner side surface 122 and the small diameter portion 57, and between the shaft portion 41 and the inner wall surface of the movable core 50. Since the housing 20, the movable core 50, and the needle 40 are provided so that the gaps between the two are several micrometers to several tens of micrometers, respectively, the free entry and exit of fuel is restricted.

In the present embodiment, the housing 20 and the movable core 50 are arranged so that the gap between the third inner side surface 123 and the large diameter portion 56 is larger than the gap between the second inner side surface 122 and the small diameter portion 57. Is provided. Therefore, the gap between the third inner side surface 123 and the large diameter portion 56 is set as the gap between the second inner side surface 122 and the small diameter portion 57 so that the large diameter portion 56 slides on the third inner side surface 123. Similarly, the machining of the housing 20 and the movable core 50 can be facilitated as compared with the case of machining to the same size as the gap between the second inner side surface 122 and the small diameter portion 57.

The valve opening operation for switching the fuel injection valve 100 from the valve closed state shown in FIG. 1 to the valve opened state shown in FIG. 3 will be described. As shown in FIG. 1, in the valve closed state, the valve portion 42 is in contact with the valve seat 32, so that the injection hole 31 is closed. In the closed state, no current is supplied to the coil 70. The needle 40 is urged toward the −Z direction by the first urging member 81, and the movable core 50 is urged toward the + Z direction by the second urging member 82. Therefore, the needle 40 and the movable core 50 are stationary in a state where the enlarged diameter portion 43 and the large diameter portion 56 are in contact with each other. A gap is provided between the movable core 50 and the fixed core 60 so that the movable core 50 can move in the valve opening operation. The fuel flowing in from the introduction port 14 flows in the order of the fuel introduction pipe 12, the inside of the fixed core 60, the fuel passage 44, and the communication hole 45, and is guided to the injection hole 31. A part of the fuel flowing in from the introduction port 14 is a gap between the second inner side surface 122 and the small diameter portion 57, a gap between the first inner side surface 121 and the shaft portion 41, and the shaft portion 41 and the movable core. It flows into the damper chamber 25 through a gap between the inner wall surface of the 50 and the inner wall surface of the 50. Therefore, the damper chamber 25 is filled with fuel.

When the supply of electric current to the coil 70 is started, a magnetic attraction force is generated between the fixed core 60 and the movable core 50, and the movable core 50 moves toward the fixed core 60 in the + Z direction. .. When the enlarged diameter portion 43 is pushed by the large diameter portion 56, the needle 40 moves together with the movable core 50. The movement of the needle 40 causes the valve portion 42 to move away from the valve seat 32, and fuel injection from the injection hole 31 is started.

By increasing the volume of the damper chamber 25 in response to the movement of the movable core 50 in the + Z direction, the pressure of the fuel in the damper chamber 25 decreases. Therefore, a force for decelerating the movable core 50 and the needle 40 acts on the movable core 50. When the movable core 50 collides with the fixed core 60, the movement of the movable core 50 is stopped. In other words, the fixed core 60 regulates the movement of the movable core 50 in the + Z direction. Since the movable core 50 is decelerated by the damper chamber 25, the impact force when the movable core 50 collides with the fixed core 60 is reduced.

After the movable core 50 collides with the fixed core 60, the needle 40 continues to move in the + Z direction by inertia independently of the movable core 50. The first urging member 81 is pushed by the enlarged diameter portion 43 and contracts in response to the movement of the needle 40, so that elastic energy is stored in the first urging member 81. After that, the needle 40 is pushed back toward the movable core 50 in the −Z direction by the elastic energy stored in the first urging member 81. When the enlarged diameter portion 43 collides with the large diameter portion 56, the movement of the needle 40 is stopped. Since the needle 40 is decelerated by the damper chamber 25 when moving together with the movable core 50, the elastic energy stored in the first urging member 81 is reduced. Therefore, the impact force when the enlarged diameter portion 43 collides with the large diameter portion 56 is reduced. After the movement of the movable core 50 is stopped, fuel flows into the damper chamber 25 through a gap or the like between the second inner side surface 122 and the small diameter portion 57. By the series of operations described above, the fuel injection valve 100 is brought into the valve open state shown in FIG. In the valve open state, a predetermined amount of fuel is injected from the injection hole 31. The fuel injection valve 100 is kept in the open state while the current supply to the coil 70 is continued.

The valve closing operation for switching the fuel injection valve 100 from the valve open state shown in FIG. 3 to the valve closed state shown in FIG. 1 will be described. By stopping the supply of electric current to the coil 70, the magnetic attraction force between the fixed core 60 and the movable core 50 disappears. Therefore, the needle 40 is pushed by the first urging member 81 and moves toward the −Z direction side. When the large diameter portion 56 is pushed by the enlarged diameter portion 43, the movable core 50 moves toward the −Z direction side together with the needle 40.

As the volume of the damper chamber 25 is reduced in response to the movement of the movable core 50 in the −Z direction, the pressure of the fuel in the damper chamber 25 increases. Therefore, a force for decelerating the movable core 50 and the needle 40 acts on the movable core 50. When the pressure of the fuel in the damper chamber 25 rises, the fuel in the damper chamber 25 gradually flows out of the damper chamber 25 through a gap or the like between the second inner side surface 122 and the small diameter portion 57. When the valve portion 42 collides with the valve seat 32, the movement of the needle 40 is stopped. In other words, the valve seat 32 regulates the movement of the needle 40 in the −Z direction. Since the needle 40 is decelerated by the damper chamber 25, the impact force when the valve portion 42 collides with the valve seat 32 is reduced. When the valve portion 42 comes into contact with the valve seat 32, the injection hole 31 is closed, so that the injection of fuel from the injection hole 31 is stopped.

After the needle 40 collides with the valve seat 32, the movable core 50 continues to move in the −Z direction by inertia independently of the needle 40. Since the volume of the damper chamber 25 is further reduced by the movement of the movable core 50, a force for decelerating the movable core 50 acts on the movable core 50. The second urging member 82 is pushed by the movable core 50 and contracts in response to the movement of the movable core 50, so that elastic energy is stored in the second urging member 82. After that, the movable core 50 is pushed back toward the + Z direction by the elastic energy stored in the second urging member 82. When the large diameter portion 56 comes into contact with the enlarged diameter portion 43, the movement of the movable core 50 is stopped. Since the movable core 50 is decelerated by the damper chamber 25, the elastic energy stored in the second urging member 82 is reduced. Therefore, the impact when the large diameter portion 56 comes into contact with the enlarged diameter portion 43 is reduced. By the series of operations described above, the fuel injection valve 100 is brought into the closed state shown in FIG. In the closed state, the injection of fuel from the injection hole 31 is stopped.

According to the fuel injection valve 100 of the present embodiment described above, the gap between the first inner side surface 121 of the housing 20 and the shaft portion 41 of the needle 40, the second inner side surface 122 of the housing 20, and the movable core 50. The impact at the on-off valve is reduced by the damper chamber 25 in which fuel enters and exits through the gap between the small diameter portion 57 and the gap between the shaft portion 41 and the inner wall surface of the movable core 50. Various strains can occur in the housing 20. For example, when fuel is supplied to the fuel injection valve 100 from the supply pipe, the backup ring 91 receives pressure from the fuel via the O-ring 92, so that the third inner side surface 123 of the housing 20 An axial force along the Z direction acts on the provided portion, and elastic strain may occur in the housing 20. In addition, when the fuel injection valve 100 is mounted on the mounting target OB such as an engine, the holder 17 is held by an operator or the like, and the support surface 90 is pressed against the mounting target OB, thereby causing the housing. Axial force along the Z direction acts on the portion of 20 provided with the third inner side surface 123, which may cause plastic strain in the housing 20. In the present embodiment, since the housing 20 is provided with the first inner side surface 121 and the second inner side surface 122 inside the third inner side surface 123 in the radial direction, the third inner side surface 123 of the housing 20 is provided. Even when the above-mentioned axial force acts on the portion, the size of the gap between the first inner surface 121 and the shaft 41 and the space between the second inner surface 122 and the small diameter portion 57 It is possible to suppress the change in the size of the gap. Therefore, it is possible to prevent the damper chamber 25 from reducing the impact reduction effect. In particular, when the fuel injection valve 100 injects hydrogen gas, which is a gaseous fuel, as in the present embodiment, the viscosity is lower than that of the liquid fuel, so that the impact at the time of the on-off valve tends to be large. Therefore, by suppressing the decrease in the impact reduction effect due to the damper chamber 25, it is possible to effectively suppress the wear and failure of the movable core 50 and the like.

Further, in the present embodiment, the housing 20 is provided with the first inner side surface 121 and the second inner side surface 122 on the −Z direction side with respect to the support surface 90 that bears the above-mentioned axial force. It is possible to more effectively suppress the occurrence of strain in the portion provided with the first inner side surface 121 and the portion provided with the second inner surface 122. Therefore, it is possible to more effectively suppress changes in the size of the gap between the first inner side surface 121 and the shaft portion 41 and the size of the gap between the second inner side surface 122 and the small diameter portion 57. ..

Since the gap between the third inner side surface 123 and the large diameter portion 56 of the movable core 50 is not a gap for ensuring the impact reduction effect of the damper chamber 25, the third inner side surface 123 and the large diameter portion 56 are not provided. Even if the size of the gap between the damper chamber 25 is changed, the impact reduction effect of the damper chamber 25 is hardly affected. Since the gap between the third inner surface 123 and the large diameter portion 56 is provided larger than the gap between the second inner surface 122 and the small diameter portion 57, the large diameter portion 56 is the third inner surface. It is possible to prevent the movable core 50 from being unable to move along the Z direction due to interference with 123, and to prevent the large diameter portion 56 and the third inner side surface 123 from rubbing against each other and being worn. Since the above-mentioned axial force is not transmitted to the needle 40 and the movable core 50, the size of the gap between the shaft portion 41 and the inner wall surface of the movable core 50 is unlikely to change.

B. Second embodiment:
As shown in FIG. 4, in the fuel injection valve 100b of the second embodiment, the shape of the needle 40b, the shape of the fixed core 60b, and the arrangement of the damper chamber 25b are different from those of the first embodiment. Other configurations and on-off valve operation are the same as those in the first embodiment unless otherwise specified.

The needle 40b has an extension portion 46 protruding from the diameter expansion portion 43 toward the + Z direction. The extension portion 46 has a cylindrical shape centered on the central axis CL. The outer diameter of the extension portion 46 is smaller than the outer diameter of the expansion portion 43. The fuel passage 44b has an opening on the end surface of the extension portion 46 on the + Z direction side.

As shown in FIG. 5, in the fixed core 60b, the inner side surface 161 of the first core in which the enlarged diameter portion 43 slides in the Z direction and the extension portion 46 slide in the Z direction in order from the −Z direction side. It has a moving second core inner surface 162. The inner side surface 161 of the first core and the inner side surface 162 of the second core each have a cylindrical shape centered on the central axis CL. The inner diameter of the inner surface 161 of the first core is larger than the inner diameter of the inner surface 162 of the second core. The fixed core 60b has a core step surface 163 that connects between the inner side surface 161 of the first core and the inner side surface 162 of the second core. The core stepped surface 163 has an annular shape centered on the central axis CL. In the present embodiment, the inner side surface 161 of the first core, the inner side surface 162 of the second core, and the stepped surface 163 of the core are provided on the second fixed core member 62.

The damper chamber 25b is partitioned by a diameter-expanded portion 43, an inner side surface 161 of the first core, a core stepped surface 163, and an extension portion 46. The inside of the damper chamber 25b communicates with the outside of the damper chamber 25b through a gap between the inner side surface 161 of the first core and the enlarged diameter portion 43 and a gap between the inner side surface 162 of the second core and the extension portion 46. ing.

In the present embodiment, the gap between the second inner side surface 122b of the first tubular member 21b of the housing 20b and the small diameter portion 57 of the movable core 50 is the second of the first tubular member 21 of the housing 20 in the first embodiment. It is provided wider than the gap between the inner side surface 122 and the small diameter portion 57 of the movable core 50. Therefore, the space partitioned by the second inner side surface 122b, the first stepped surface 124, the shaft portion 41, and the small diameter portion 57 does not function as a damper chamber. In this embodiment, the second urging member 82 is arranged in this space. The housing 20b may have the same configuration as that of the first embodiment. That is, the space surrounded by the second inner side surface 122b, the first stepped surface 124, the shaft portion 41, and the small diameter portion 57 may have a function as a damper chamber as in the first embodiment, and may have a second function. The urging member 82 may be provided at the same position as in the first embodiment.

In the valve opening operation of the fuel injection valve 100b, when the movable core 50 and the needle 40b move in the + Z direction, the volume of the damper chamber 25b is reduced, so that the damper chamber 25b causes the movable core 50 and the needle 40b to move. It will be decelerated. Therefore, the impact when the movable core 50 collides with the fixed core 60b is reduced. After the movable core 50 collides with the fixed core 60b, when the needle 40b moves independently of the movable core 50, the volume of the damper chamber 25b is further reduced, and the needle 40b is further decelerated. Therefore, the elastic energy stored in the first urging member 81 is reduced. Further, when the needle 40b is pushed back in the −Z direction by the first urging member 81, the volume of the damper chamber 25b is expanded, so that the needle 40b is decelerated. Therefore, the impact when the enlarged diameter portion 43 collides with the large diameter portion 56 of the movable core 50 is reduced.

In the valve closing operation of the fuel injection valve 100b, when the needle 40b and the movable core 50 move in the −Z direction, the volume of the damper chamber 25b is expanded. Is decelerated. Since the needle 40b is decelerated, the impact when the valve portion 42 collides with the valve seat 32 is reduced. Since the movable core 50 is decelerated, the elastic energy stored in the second urging member 82 is reduced. The impact when the movable core 50 is pushed back in the + Z direction by the second urging member 82 and the large diameter portion 56 comes into contact with the enlarged diameter portion 43 is reduced.

According to the fuel injection valve 100b of this form, the gap between the inner surface 161 of the first core of the fixed core 60b and the enlarged diameter portion 43 of the needle 40b, and the inner surface 162 of the second core of the fixed core 60b and the needle 40b The impact at the time of the on-off valve is reduced by the damper chamber 25b in which the fuel enters and exits through the gap between the extension portion 46 and the fuel. Even if the housing 20b is distorted, the needle 40b and the fixed core 60b are hardly distorted. Therefore, even when the housing 20 is distorted, the size of the gap between the inner side surface 161 of the first core and the enlarged diameter portion 43 and the gap between the inner side surface 162 of the second core and the extension portion 46 It is possible to prevent the damper chamber 25b from reducing the impact reduction effect due to the change in the size of the damper chamber 25b.

C. Third Embodiment:
As shown in FIG. 6, in the fuel injection valve 100c of the third embodiment, the shim 26 is provided in the housing 20c, and the damper chamber 25c is provided by the end surface 126 of the shim 26 instead of the first step surface 124c of the housing 20c. Is different from the first embodiment in that is partitioned. Other configurations and on-off valve operation are the same as those in the first embodiment unless otherwise specified.

As shown in FIG. 7, the shim 26 is provided between the second inner side surface 122c of the first tubular member 21c of the housing 20c and the shaft portion 41 of the needle 40. The shim 26 has a cylindrical shape centered on the central axis CL. The shaft portion 41 penetrates the inside of the shim 26, and the shaft portion 41 slides on the inner wall surface of the shim 26. In this embodiment, the shim 26 is fixed to the second inner surface 122c by press fitting. The end face 126 on the + Z direction side of the shim 26 faces the end face on the −Z direction side of the small diameter portion 57 of the movable core 50. In the radial direction of the housing 20c, the end face 126 is provided between the first inner side surface 121 and the second inner side surface 122c in the housing 20c. The end face 126 is provided so as to connect a step generated between the second inner side surface 122c of the housing 20c and the inner wall surface of the shim 26. Therefore, in the following description, the end surface 126 is referred to as a third step surface 126.

The damper chamber 25c is partitioned by a second inner side surface 122c, a third stepped surface 126, a shaft portion 41, and a small diameter portion 57. Inside the damper chamber 25c, there is a gap between the second inner side surface 122c and the small diameter portion 57, a gap between the shaft portion 41 and the inner wall surface of the movable core 50, and the inner wall surface of the shim 26 and the shaft portion 41. It communicates with the outside of the damper chamber 25c through a gap between them.

According to the fuel injection valve 100c of this form, the volume of the damper chamber 25c can be easily adjusted by adjusting the position of the shim 26 in the Z direction. Therefore, the impact reduction effect of the damper chamber 25c can be easily adjusted.

D. Other embodiments:
(D-1) In the fuel injection valves 100 to 100c of each of the above-described embodiments, the first inner side surface 121 and the second inner side surface 122 to 122c are provided on the −Z direction side with respect to the support surface 90. On the other hand, the second inner side surfaces 122 to 122c may be provided at positions intersecting the support surface 90, and the first inner side surface 121 may be provided on the −Z direction side with respect to the support surface 90. The second inner side surfaces 122 to 122c may be provided on the + Z direction side of the support surface 90, and the first inner side surface 121 may be provided on the −Z direction side of the support surface 90. The second inner side surfaces 122 to 122c may be provided on the + Z direction side with respect to the support surface 90, and the first inner side surface 121 may be provided at a position where the support surface 90 intersects. The first inner side surface 121 and the second inner side surfaces 122 to 122c may be provided on the + Z direction side of the support surface 90.

(D-2) In the fuel injection valve 100 of the first embodiment and the fuel injection valve 100c of the third embodiment described above, the second urging member 82 is arranged outside the damper chambers 25 and 25c. On the other hand, the second urging member 82 may be arranged in the damper chambers 25 and 25c.

(D-3) In the fuel injection valves 100 to 100c of each of the above-described embodiments, the first cylinder members 21 to 21c of the housings 20 to 20c and the injection nozzle 30 are composed of separate members. On the other hand, the first cylinder member 21 to 21c and the injection nozzle 30 may be composed of one member. In this case, the injection hole 31 and the valve seat 32 may be provided at the ends of the first cylinder members 21 to 21c on the −Z direction side.

(D-4) In the fuel injection valves 100 to 100c of each of the above-described embodiments, the movable core 50 has a large diameter portion 56 and a small diameter portion 57 having different outer diameters from each other. On the other hand, the movable core 50 does not have to have portions having different outer diameters from each other. That is, the outer diameter of the movable core 50 may be constant.

(D-5) In the fuel injection valves 100 to 100c of each of the above-described embodiments, the movable core 50 is composed of a first movable core member 51 and a second movable core member 52. On the other hand, the movable core 50 may be composed of only the first movable core member 51.

(D-6) In the fuel injection valves 100 to 100c of each of the above-described embodiments, the fixed cores 60 and 60b are composed of a first fixed core member 61 and a second fixed core member 62. On the other hand, the fixed cores 60 and 60b may be composed of only the first fixed core member 61.

The present disclosure is not limited to the above-described embodiment, and can be realized by various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments may be replaced or combined as appropriate to solve some or all of the above-mentioned problems, or to achieve some or all of the above-mentioned effects. Is possible. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

11 ... Adjusting pipe, 12 ... Fuel introduction pipe, 13 ... Filter, 14 ... Introduction port, 15 ... Connector, 16 ... Terminal, 17 ... Holder, 18 ... Cover, 20 ... Housing, 21 ... First cylinder member, 22 ... 2nd cylinder member, 23 ... 3rd cylinder member, 24 ... 4th cylinder member, 25 ... damper chamber, 26 ... shim, 30 ... injection nozzle, 31 ... injection hole, 32 ... valve seat, 40 ... needle, 41 ... shaft Part, 42 ... Valve part, 43 ... Diameter expansion part, 44 ... Fuel passage, 45 ... Communication hole, 46 ... Extension part, 50 ... Movable core, 51 ... First movable core member, 52 ... Second movable core member, 56 ... Large diameter part, 57 ... Small diameter part, 60 ... Fixed core, 61 ... First fixed core member, 62 ... Second fixed core member, 70 ... Coil, 71 ... Bobbin, 81 ... First urging member, 82 ... No. 2 urging member, 90 ... support surface, 91 ... backup ring, 92 ... O ring, 100 ... fuel injection valve, 121 ... first inner surface, 122 ... second inner surface, 123 ... third inner surface, 124 ... second 1 step surface, 125 ... second step surface, 126 ... third step surface, 161 ... first core inner surface, 162 ... second core inner surface, 163 ... core step surface

Claims (6)

Fuel injection valve (100, 100c)
A tubular housing (20, 20c) having a longitudinal direction (Z) and having a injection hole (31) for injecting fuel at one end in the longitudinal direction.
A fixed core (60) fixed in the housing and
A movable core (50) arranged on one end side of the fixed core and movable in the housing along the longitudinal direction,
A needle (40) that opens and closes the injection hole by moving along the longitudinal direction in the housing as the movable core moves.
A coil (70) that generates a magnetic field that moves the movable core, and
With
The housing is provided in order from the one end side, on the first inner side surface (121) on which the needle slides along the longitudinal direction, and on the outer side in the radial direction where the needle intersects the first inner side surface in the longitudinal direction. The movable core has a second inner surface (122, 122c) that slides along the longitudinal direction, and a third inner surface (123) to which the fixed core is fixed.
It has a stepped surface (124,126) provided between the first inner surface and the second inner surface in the housing.
The damper chamber (25, 25c) in which the fuel is sealed is partitioned by the second inner surface surface, the stepped surface, the needle, and the movable core.
The second inner surface is a fuel injection valve provided inside the third inner surface in the radial direction. The fuel injection valve according to claim 1.
The fuel injection valve has a support surface (90) supported by the mounting object from one end side in the mounted state when the fuel injection valve is mounted on the mounting object (OB).
The second inner surface is a fuel injection valve provided between the support surface and the injection hole in the longitudinal direction. The fuel injection valve (100) according to claim 1 or 2.
A tubular shim (26) fixed between the second inner surface and the movable core is provided.
The stepped surface is a fuel injection valve provided on the shim. The fuel injection valve according to any one of claims 1 to 3.
The fuel is a gas fuel, a fuel injection valve. The fuel injection valve according to any one of claims 1 to 4.
The fuel is a hydrogen fuel, a fuel injection valve. It is a fuel injection valve (100b)
A tubular housing (20b) having a longitudinal direction (Z) and having a injection hole (31) for injecting fuel at one end in the longitudinal direction.
A tubular fixed core (60b) fixed in the housing and
A movable core (50) arranged on one end side of the fixed core and movable in the housing along the longitudinal direction,
A needle (40b) that opens and closes the injection hole by moving along the longitudinal direction in the housing as the movable core moves.
A coil (70) that generates a magnetic field that moves the movable core, and
With
The needles are, in order from the one end side, a shaft portion (41) provided along the longitudinal direction, a diameter-expanded portion (43) having an outer diameter larger than the outer diameter of the shaft portion, and the longitudinal direction. It has an extension portion (46) provided along the above and having an outer diameter smaller than the outer diameter of the enlarged diameter portion.
The fixed core has an inner surface (161) of the first core on which the enlarged diameter portion slides and an inner diameter smaller than the inner diameter of the inner surface of the first core, and the inside of the second core on which the extension portion slides. It has a side surface (162) and a core stepped surface (163) provided between the inner surface of the first core and the inner surface of the second core in the fixed core.
A fuel injection valve in which a damper chamber (25b) in which the fuel is sealed is partitioned by the enlarged diameter portion, the extension portion, the inner surface surface of the first core, and the stepped surface of the core.

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