JP7323445B2 - fuel injector - Google Patents

Description

The present disclosure relates to fuel injectors.

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, by decelerating the movable core using the pressure change of the fuel in the damper chamber accompanying the movement of the movable core, the impact due to the collision between the movable core and the fixed core when the valve opens and the needle when the valve closes. and valve seat.

Japanese Patent Application Laid-Open No. 2018-189002

In the fuel injection valve described above, the movable core has a large-diameter portion and a small-diameter portion with different outer diameters, which slide on portions with different inner diameters of the housing. Since the portion where the large diameter portion slides and the portion where the small diameter portion slides are provided in one member, it is difficult to machine each portion with high dimensional accuracy. If the actual gap between the moving core and the housing becomes narrower than the designed gap, the sliding resistance between the moving core and the housing increases, and in the worst case, the moving core may be locked and unable to move. There is Therefore, if the design gap between the movable core and the housing is increased, there is a possibility that the impact reduction effect of the damper chamber will not be sufficiently exhibited.

The present disclosure can be implemented as the following forms.

According to one aspect of the present disclosure, a fuel injector (100, 100b, 100c, 100d) is provided. This fuel injection valve has a longitudinal direction (Z) and has a cylindrical housing (20, 20d) provided with an injection hole (31, 31d) for injecting fuel at one end in the longitudinal direction; A fixed core (60) fixed in a housing, a movable core (50) arranged on the one end side of the fixed core and movable in the housing along the longitudinal direction, and movement of the movable core a needle (40) for opening and closing the nozzle hole by moving along the longitudinal direction in the housing along with the needle (40); and a coil (70) for generating a magnetic field for moving the movable core. The movable core has a large-diameter portion (56) facing the fixed core and a small-diameter portion (57) provided closer to the one end than the large-diameter portion and having an outer diameter smaller than the outer diameter of the large-diameter portion. ), the housing includes a first portion (122) in which the small diameter portion is movably arranged, and a large diameter portion is movably arranged and has an inner diameter larger than the inner diameter of the first portion. and a stepped portion (125) provided between the first portion and the second portion in the housing, and the stepped portion in the housing is in contact with the stepped portion. A cylindrical inner member (90, 90b, 90c, 90d) having a flange portion (92, 92b) that extends across the longitudinal direction so that a gap is formed with the first portion in a radial direction that intersects the longitudinal direction. is disposed, and a damper chamber (25) in which the fuel is enclosed is defined in the housing by the inner surface of the second portion, the flange portion, the small diameter portion, and the large diameter portion, and the large diameter portion slides on the inner surface of the second portion, and the outer surface of the small diameter portion slides on the inner surface of the inner member.

According to this embodiment of the fuel injection valve, the housing that slides on the large-diameter portion of the movable core and the inner member that slides on the small-diameter portion of the movable core are made of separate members. Easier to process. Therefore, it becomes easy to provide the gap between the large diameter portion and the housing and the gap between the small diameter portion and the inner member with the intended size, so that it is possible to prevent the movable core from being locked and unable to move. In addition, the impact reduction effect of the damper chamber can be sufficiently exhibited.

1 is a first explanatory diagram showing a schematic configuration of a fuel injection valve according to a first embodiment; FIG. FIG. 2 is a partially enlarged view of part A in FIG. 1; FIG. 2 is a second explanatory diagram showing a schematic configuration of the fuel injection valve of the first embodiment; Explanatory drawing which shows schematic structure of the fuel injection valve of 2nd Embodiment. FIG. 5 is an explanatory diagram showing a schematic configuration of a fuel injection valve according to a third embodiment; Explanatory drawing which shows schematic structure of the fuel injection valve of 4th Embodiment. FIG. 7 is a partially enlarged view of a B portion in FIG. 6;

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

The housing 20 has a longitudinal direction along the Z direction. The housing 20 is configured by connecting a first cylinder member 21, a second cylinder member 22, a third cylinder member 23, and a fourth cylinder member 24 in this order toward the +Z direction side. Each of the tubular members 21 to 24 has 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 first cylindrical member 21 on the -Z direction side. A valve seat 32 with which the valve portion 42 of the needle 40 contacts is provided on the periphery of the nozzle hole 31 of the first cylindrical member 21 . In this embodiment, between the first tubular member 21 and the second tubular member 22, between the second tubular member 22 and the third tubular member 23, and between the third tubular member 23 and the fourth tubular member 24, The spaces are fixed to each other by welding, press-fitting, or the like. The first cylindrical member 21 is made of martensitic stainless steel, which is a metal material, and is quenched so as to have a predetermined hardness. The second cylindrical member 22 and the fourth cylindrical member 24 are made of ferritic stainless steel, which is a magnetic material. The third cylindrical member 23 is made of austenitic stainless steel, which is a non-magnetic material.

An inner member 90 is housed inside the first cylindrical member 21 . The inner member 90 has a cylindrical shape centered on the central axis CL along the Z direction. In this embodiment, the inner member 90 is housed inside the first tubular member 21 so that a gap is formed between the inner member 90 and the first tubular member 21 in the radial direction. As will be described later, the inner member 90 is fixed by being pressed against the first cylindrical member 21 in the -Z direction by the second biasing member 82 . The inner member 90 is made of martensitic stainless steel, which is a metal material, and is quenched so as to have a predetermined hardness. A specific configuration of the inner member 90 will be described later.

The fuel introduction pipe 12 is connected to the fourth tubular member 24 . In this embodiment, the fourth cylindrical 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 inlet 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 filter 13 is provided inside the fuel introduction pipe 12 . The filter 13 collects foreign matter mixed in the fuel flowing from the inlet 14 and suppresses the foreign matter from flowing into the housing 20 .

The needle 40 is arranged in the housing 20 so as to be movable along the central axis CL. The needle 40 has a shaft portion 41 , a valve portion 42 and an enlarged diameter 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 nozzle hole 31 is closed when the valve portion 42 contacts the valve seat 32 , and the nozzle hole 31 is opened when the valve portion 42 separates from the valve seat 32 . The enlarged diameter portion 43 is provided at the +Z direction side end portion of the shaft portion 41 . 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 contacts the +Z direction end surface of the movable core 50 . A fuel passage 44 through which fuel flows along the central axis CL is provided inside the shaft portion 41 and the enlarged diameter portion 43 . The fuel passage 44 has an opening on the +Z direction side end surface of the enlarged diameter portion 43 . A side surface of the shaft portion 41 is provided with a communication hole 45 that communicates with the fuel passage 44 .

The movable core 50 is arranged in the housing 20 so as to be movable along the central axis CL. The movable core 50 has a cylindrical shape centered on the central axis CL. A shaft portion 41 passes through the inside of the movable core 50 , and the shaft portion 41 slides on the inner wall surface of the movable core 50 . Sliding refers not only to the sliding movement of one object on the surface of the other object while the two objects are in contact with each other, but also to the sliding movement of two objects close to each other with a fluid interposed between them. It also means that an object slides on the surface of another 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 protrude from the large diameter portion 56 in the -Z direction. The large-diameter portion 43 contacts the end surface of the large-diameter portion 56 on the +Z direction side.

In this embodiment, the movable core 50 is composed of a first movable core member 51 made of a magnetic material and a second movable core member 52 having hardness higher than that 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). A body portion of the movable core 50 is composed of a first movable core member 51 . The portion of movable core 50 that slides on housing 20, the portion that contacts fixed core 60, the portion that contacts or slides needle 40, and the portion that contacts or slides on inner member 90 are the first. It is composed of two movable core members 52 . In this 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 quenched 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 on the +Z direction side of the movable core 50 in the housing 20 . In this embodiment, the fixed core 60 is fixed to the fourth cylindrical member 24 by welding or the like. Fixed core 60 has a cylindrical shape centered on 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 moving along the central axis CL contacts the end surface of the fixed core 60 on the -Z direction side. The adjusting pipe 11 having a cylindrical shape centered on the central axis CL is press-fitted to the +Z direction side portion inside the fixed core 60 .

In this embodiment, the fixed core 60 is composed of a first fixed core member 61 made of a magnetic material and a second fixed core member 62 having a hardness higher than that of the first fixed core member 61. . The hardness of the first stationary core member 61 and the hardness of the second stationary core member 62 can be examined by a Vickers hardness test (JIS Z 2244). A body portion of the fixed core 60 facing the first movable core member 51 is configured by the first fixed core member 61 . A portion of the fixed core 60 on which the expanded diameter portion 43 slides is constituted by a second fixed core member 62 . A portion of the fixed core 60 that the movable core 50 contacts from the -Z direction side is constituted by a second fixed core member 62 . In this embodiment, the fixed core is configured so that the end surface of the second fixed core member 62 on the -Z direction side protrudes several tens of micrometers in the -Z direction side from the end surface of the first fixed core member 61 on the -Z direction side. It is When the movable core 50 contacts the fixed core 60 , the second movable core member 52 contacts the second fixed core member 62 , and a gap is formed between the first fixed core member 61 and the first movable core member 51 . is provided. In this embodiment, the first stationary core member 61 is made of ferritic stainless steel, which is a magnetic material. The second stationary core member 62 is made of martensitic stainless steel, which is a metallic material, and is quenched 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 fixed core 60 is configured so that the end surface of the first fixed core member 61 on the -Z direction side and the end surface of the second fixed core member 62 on the -Z direction side are flush with each other. The movable core 50 may be configured such that the end surface of the +Z direction side of the first movable core member 51 protrudes several tens of micrometers toward the +Z direction side from the +Z direction side end surface of the first movable core member 51 .

The first biasing member 81 is arranged inside the fixed core 60 between the adjusting pipe 11 and the enlarged diameter portion 43 . The first biasing member 81 biases the needle 40 in the -Z direction. In this embodiment, the first biasing member 81 is configured by a coil spring that expands and contracts along the Z direction. The +Z direction side end of the first biasing member 81 is in contact with the adjusting pipe 11, and the -Z direction side end of the first biasing member 81 is in contact with the enlarged diameter portion 43. . The force with which the first biasing member 81 biases the needle 40 can be adjusted by adjusting the position of the adjusting pipe 11 in the Z direction. In the present embodiment, the adjusting pipe is arranged such that the force with which the first biasing member 81 biases the needle 40 is greater than the force with which the second biasing member 82 described later biases the movable core 50 . Eleven positions have been adjusted.

The second biasing member 82 is arranged between the inner member 90 and the small diameter portion 57 . The second biasing member 82 biases the movable core 50 in the +Z direction. In this embodiment, the second biasing member 82 is configured by a coil spring that expands and contracts along the Z direction. The −Z direction side end of the second biasing member 82 is in contact with the bottom surface portion 93 of the inner member 90 described later, and the +Z direction side end of the second biasing member 82 is in contact with the small diameter portion 57 . in contact.

A bobbin 71 around which a coil 70 is wound is arranged on the outer wall surface of the housing 20 . In this embodiment, the bobbin 71 is arranged across the outer wall surface of the third cylindrical member 23 and the outer wall surface of the fourth cylindrical member 24 . A portion of the outer wall surface of the fourth cylindrical member 24 where the bobbin 71 is not arranged and a portion of the outer wall surface of the fuel introduction pipe 12 are coated with a resin material. A connector 15 is provided on the side of the fourth tubular member 24 so as to protrude from the outer wall surface of the fourth tubular member 24 . The connector 15 is provided with a terminal 16 electrically connected to the coil 70 . In this embodiment, metal terminals 16 are provided on a 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 being supplied with current from a power supply. The magnetic field generated by the coil 70 forms a magnetic circuit passing through the second tubular member 22 , the first fixed core member 61 , the first movable core member 51 and the fourth tubular member 24 . Therefore, a magnetic attractive force is generated between the movable core 50 and the fixed core 60 . A cylindrical holder 17 is provided around 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 constitute a part of the magnetic circuit described above.

As shown in FIG. 2, the housing 20 has, in order from the -Z direction side, a first inner side surface 121 that accommodates the shaft portion 41, a second inner side surface 122 that accommodates the inner member 90, and a large diameter portion 56. and a moving third inner surface 123 . The first inner side surface 121, the second inner side surface 122, and the third inner side 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 . The first inner side surface 121 and the second inner side surface 122 are connected by a first stepped surface 124 . A second step surface 125 connects the second inner surface 122 and the third inner surface 123 . The first stepped surface 124 and the second stepped surface 125 each have an annular shape centered on the central axis CL. In the housing 20, the portion provided with the second inner surface 122 may be referred to as the first portion, and the portion provided with the third inner surface 123 may be referred to as the second portion. The portion where the second stepped surface 125 is provided is sometimes called a stepped portion.

The inner member 90 has a tubular portion 91 , a flange portion 92 and a bottom portion 93 . The tubular portion 91 has a cylindrical shape centered on the central axis CL. The inner wall surface of the tubular portion 91 is provided with a fourth inner surface 191 on which the small diameter portion 57 slides. The flange portion 92 is provided along the second step surface 125 and protrudes radially outward of the tubular portion 91 from the +Z direction side end of the tubular portion 91 . The bottom surface portion 93 is provided along the first stepped surface 124 and protrudes radially inward of the tubular portion 91 from the −Z direction side end of the tubular portion 91 . The flange portion 92 and the bottom portion 93 each have an annular shape centered on the central axis CL. The outer diameter of the flange portion 92 is smaller than the inner diameter of the third inner side surface 123 . The outer diameter of the cylindrical portion 91 is smaller than the inner diameter of the second inner side surface 122 . The inner diameter of the bottom portion 93 is larger than the outer diameter of the shaft portion 41 . Therefore, in the radial direction, a gap of a predetermined width is provided between the flange portion 92 and the third inner side surface 123, and a gap of a predetermined width is provided between the cylindrical portion 91 and the second inner side surface 122. A gap is provided, and a gap having a predetermined width is provided between the bottom surface portion 93 and the shaft portion 41 . A gap having a predetermined width is provided between the bottom surface portion 93 and the first stepped surface 124 in the Z direction. As described above, the second biasing member 82 is provided between the bottom surface portion 93 and the small diameter portion 57, and the inner member 90 is biased toward the −Z direction by the second biasing member 82. ing. Therefore, the flange portion 92 is pressed against the second stepped surface 125 in the -Z direction, and the sealing performance between the flange portion 92 and the second stepped surface 125 is ensured.

A damper chamber 25 surrounded by the third inner surface 123 , the second stepped surface 125 , the flange portion 92 , the small diameter portion 57 and the large diameter portion 56 is provided in the housing 20 . Fuel is enclosed in the damper chamber 25 . Encapsulated fuel does not mean that the fuel is completely enclosed, but rather that the fuel is enclosed to such an extent that its free ingress and egress is restricted. The inside of the damper chamber 25 communicates with the outside of the damper chamber 25 through a gap between the third inner side surface 123 and the large diameter portion 56 and a gap between the fourth inner side surface 191 and the small diameter portion 57 . . In the present embodiment, the gap between the third inner surface 123 and the large diameter portion 56 and the gap between the fourth inner surface 191 and the small diameter portion 57 are each set to several micrometers to ten and several micrometers. Since the housing 20, the movable core 50, and the inner member 90 are provided in such a manner that the fuel flows freely in and out, the fuel is restricted.

A valve opening operation for switching the fuel injection valve 100 from the valve closed state shown in FIG. 1 to the valve open state shown in FIG. 3 will be described. As shown in FIG. 1, in the closed state, the valve portion 42 is in contact with the valve seat 32, so the nozzle hole 31 is closed. In the closed state, the coil 70 is not energized. The needle 40 is biased toward the −Z direction by the first biasing member 81 , and the movable core 50 is biased toward the +Z direction by the second biasing member 82 . Therefore, the needle 40 and the movable core 50 are stationary while the enlarged diameter portion 43 of the needle 40 and the large diameter portion 56 of the movable core 50 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 during the valve opening operation. The fuel that has flowed in from the inlet 14 flows through the fuel inlet pipe 12 , the inside of the fixed core 60 , the fuel passage 44 , and the communication hole 45 in that order, and is led to the injection hole 31 . Part of the fuel that has flowed in from the inlet 14 enters the damper chamber 25 through the gap between the third inner side surface 123 and the large diameter portion 56 and the gap between the fourth inner side surface 191 and the small diameter portion 57. flow into Therefore, the damper chamber 25 is filled with fuel.

When the current supply to the coil 70 is started, a magnetic attraction force is generated between the first fixed core member 61 of the fixed core 60 and the first movable core member 51 of the movable core 50, and the movable core 50 moves toward the fixed core 60 in the +Z direction. The needle 40 moves together with the movable core 50 by the enlarged diameter portion 43 being pushed by the large diameter portion 56 . Due to the movement of the needle 40, the valve portion 42 is separated from the valve seat 32, and fuel injection from the injection hole 31 is started.

The volume of the damper chamber 25 is expanded in accordance with the movement of the movable core 50 in the +Z direction, thereby reducing the pressure of the fuel in the damper chamber 25 . Therefore, a force that decelerates the movable core 50 and the needle 40 acts on the movable core 50 . When the second movable core member 52 of the movable core 50 collides with the second fixed core member 62 of the fixed core 60, the movement of the movable core 50 is stopped. In other words, the fixed core 60 restricts the movement of the movable core 50 in the +Z direction. Since the damper chamber 25 decelerates the movable core 50 , the impact force when the second movable core member 52 of the movable core 50 collides with the second fixed core member 62 of 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 . As the needle 40 moves, the first biasing member 81 is pushed by the enlarged diameter portion 43 and contracts, whereby elastic energy is stored in the first biasing 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 biasing member 81 . Movement of the needle 40 is stopped when the enlarged diameter portion 43 collides with the large diameter portion 56 . As described above, since the needle 40 and the movable core 50 are decelerated by the damper chamber 25, the impact force when the second movable core member 52 collides with the second fixed core member 62 is reduced. Furthermore, since the needle 40 is decelerated by the damper chamber 25 when the needle 40 moves together with the movable core 50, the elastic energy stored in the first biasing member 81 is reduced. Therefore, the impact force when the expanded 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 such as between the third inner surface 123 and the large diameter portion 56 . Through the series of operations described above, the fuel injection valve 100 is brought into the open state shown in FIG. A predetermined amount of fuel is injected from the nozzle hole 31 in the valve open state. While the current supply to the coil 70 continues, the fuel injection valve 100 is kept open.

A valve closing operation for switching the fuel injection valve 100 from the open state shown in FIG. 3 to the closed state shown in FIG. 1 will be described. By stopping the current supply to the coil 70, the magnetic attraction force between the first fixed core member 61 and the first movable core member 51 disappears. Therefore, the needle 40 is pushed by the first biasing member 81 and moves in the -Z direction. As the large-diameter portion 56 of the movable core 50 is pushed by the enlarged-diameter portion 43 of the needle 40 , the movable core 50 moves together with the needle 40 toward the −Z direction.

As the movable core 50 moves in the -Z direction, the volume of the damper chamber 25 is reduced, thereby increasing the pressure of the fuel in the damper chamber 25 . Therefore, a force that decelerates 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 such as between the third inner surface 123 and the large diameter portion 56 . Movement of the needle 40 is stopped by the collision of the valve portion 42 with the valve seat 32 . In other words, the valve seat 32 restricts 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. Since the injection hole 31 is closed by the contact of the valve portion 42 with the valve seat 32 , fuel injection 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 that decelerates the movable core 50 acts on the movable core 50 . As the movable core 50 moves, the second biasing member 82 is pushed by the movable core 50 and contracts, whereby elastic energy is stored in the second biasing member 82 . After that, the movable core 50 is pushed back in the +Z direction by the elastic energy stored in the second biasing member 82 . The movement of the movable core 50 is stopped by the contact of the large-diameter portion 56 with the enlarged-diameter portion 43 . Since the damper chamber 25 decelerates the movable core 50, the elastic energy stored in the second biasing member 82 is reduced. Therefore, the impact when the large-diameter portion 56 contacts the enlarged-diameter portion 43 is reduced. Through the series of operations described above, the fuel injection valve 100 is brought into the closed state shown in FIG. In the valve closed state, injection of fuel from the injection hole 31 is stopped.

According to the fuel injection valve 100 of the present embodiment described above, through the gap between the third inner side surface 123 and the large diameter portion 56 and the gap between the fourth inner side surface 191 and the small diameter portion 57, etc. The damper chamber 25 through which fuel flows in and out reduces the impact when opening and closing the valve. A third inner surface 123 on which the large diameter portion 56 slides is provided on the housing 20, and a fourth inner surface 191 on which the small diameter portion 57 slides is provided on an inner member 90 which is a member different from the housing 20. there is Therefore, compared to the case where the third inner surface 123 and the fourth inner surface 191 are provided on the same member, it is easier to process the third inner surface 123 and the fourth inner surface 191 with high dimensional accuracy. Therefore, it becomes easy to provide the gap between the large-diameter portion 56 and the third inner side surface 123 and the gap between the small-diameter portion 57 and the fourth inner side surface 191 with desired sizes, so that the movable core 50 can be locked. In addition, it is possible to make it easier for the damper chamber 25 to fully exhibit the impact reduction effect.

In particular, when the fuel injection valve 100 is configured to inject hydrogen gas, which is a gaseous fuel, as in the present embodiment, the viscosity of the fuel is lower than that of liquid fuel. Therefore, the impact reduction effect of the damper chamber 25 can effectively suppress wear, failure, and the like. Further, in the present embodiment, the gap between the third inner side surface 123 and the large diameter portion 56 and the gap between the fourth inner side surface 191 and the small diameter portion 57 can be processed more precisely. . Therefore, the impact reduction effect of the damper chamber 25 can be enhanced. Furthermore, since the volume of the damper chamber 25 can be adjusted by adjusting the plate thickness of the flange portion 92, the impact reduction effect of the damper chamber 25 can be easily adjusted. Therefore, variations in the impact reduction effect for each individual fuel injection valve 100 can be suppressed.

B. Second embodiment:
As shown in FIG. 4, in the fuel injection valve 100b of the second embodiment, the shape of the flange portion 92b of the inner member 90b differs from that of the first embodiment. Other configurations and opening/closing valve operations are the same as in the first embodiment unless otherwise specified.

The flange portion 92b has an inner peripheral portion 94 provided on the outer periphery of the tubular portion 91 in the radial direction, and an outer peripheral portion 95 provided on the outer periphery of the inner peripheral portion 94 in the radial direction. The inner peripheral portion 94 is in contact with the second stepped surface 125 , and a gap is provided between the outer peripheral portion 95 and the second stepped surface 125 . In the present embodiment, the surface of the flange portion 92b on the +Z direction side is provided flat, and the surface of the flange portion 92b on the -Z direction side is provided with a step so that the inner peripheral portion 94 and the outer peripheral portion 95 are separated. is provided. A plate thickness t2 of the outer peripheral portion 95 is smaller than a plate thickness t1 of the inner peripheral portion 94 .

Fuel flows from the damper chamber 25 into the gap between the outer peripheral portion 95 and the second step surface 125 . Since the inner peripheral portion 94 is in contact with the second stepped surface 125 , the inflow of fuel from the damper chamber 25 is restricted between the inner peripheral portion 94 and the second stepped surface 125 . The pressure of the fuel that has flowed into the gap between the outer peripheral portion 95 and the second step surface 125 is the same as the pressure of the fuel inside the damper chamber 25 . Therefore, the surface of the outer peripheral portion 95 on the +Z direction side receives a force along the Z direction from the fuel in the damper chamber 25, and the surface of the outer peripheral portion 95 on the -Z direction side is the force between the outer peripheral portion 95 and the second stepped surface 125. The force along the Z direction received from the fuel that has flowed into the gap is balanced. When the pressure of the fuel in the damper chamber 25 increases, the inner circumferential portion 94 receives force in the -Z direction. The bottom portion 93 receives a force in the −Z direction from the second biasing member 82 . Therefore, the inner peripheral portion 94 is pressed against the second step surface 125 . On the other hand, when the pressure of the fuel in the damper chamber 25 is lowered, the inner peripheral portion 94 receives force in the +Z direction. The bottom portion 93 receives a force in the −Z direction from the second biasing member 82 . The force applied to the bottom surface portion 93 in the −Z direction by the second biasing member 82 is greater than the force applied to the inner peripheral portion 94 in the +Z direction due to the pressure change of the fuel in the damper chamber 25. An outer peripheral portion 95 is provided with an area of . Therefore, even when the pressure of the fuel in the damper chamber 25 is lowered, the inner peripheral portion 94 is pressed against the second stepped surface 125 .

According to the fuel injection valve 100b of this configuration, the inner peripheral portion 94 in contact with the second stepped surface 125 and the outer peripheral portion 95 away from the second stepped surface 125 are provided in the flange portion 92b. The displacement of the inner member 90b in the +Z direction with respect to the housing 20 is suppressed when the pressure of the fuel inside decreases. Therefore, deterioration of the sealing performance between the inner peripheral portion 94 and the second stepped surface 125 can be suppressed, so that deterioration of the impact reduction effect of the damper chamber 25 can be suppressed.

C. Third embodiment:
As shown in FIG. 5, in the fuel injection valve 100c of the third embodiment, an elastic seal member 97 is provided between the cylindrical portion 91 of the inner member 90c and the second inner surface 122 of the housing 20. is different from the first embodiment. Other configurations and opening/closing valve operations are the same as in the first embodiment unless otherwise specified.

The elastic seal member 97 is composed of a rubber O-ring. The elastic seal member 97 is fitted in a groove portion 96 provided on the outer wall surface of the tubular portion 91 . The elastic seal member 97 is arranged so as to be radially crushed by the cylindrical portion 91 and the second inner side surface 122 . Therefore, the elastic sealing member 97 enhances the sealing performance between the cylindrical portion 91 and the second inner side surface 122 . When fuel flows between the cylindrical portion 91 and the second inner side surface 122, the elastic seal member 97 is crushed along the Z direction by the pressure from the fuel and swells in the radial direction. The sealing performance between 91 and the second inner surface 122 is further improved. A groove may be provided in the second inner side surface 122 instead of the tubular portion 91 , and the elastic seal member 97 may be fitted into the groove provided in the second inner side surface 122 .

According to the fuel injection valve 100c of this configuration, the elastic sealing member 97 not only improves the sealing performance of the damper chamber 25, but also reduces the pressure of the fuel in the damper chamber 25 due to the frictional force from the elastic sealing member 97. In this case, the displacement of the inner member 90c in the +Z direction with respect to the housing 20 is suppressed. Therefore, deterioration of the sealing performance between the flange portion 92 and the second stepped surface 125 can be suppressed, so that deterioration of the impact reduction effect of the damper chamber 25 can be suppressed.

D. Fourth embodiment:
As shown in FIG. 6, the fuel injection valve 100d of the fourth embodiment differs from the first embodiment in that a third biasing member 83 is arranged between the housing 20d and the inner member 90d. Other configurations and opening/closing valve operations are the same as in the first embodiment unless otherwise specified.

In this embodiment, the housing 20d has the injection nozzle 30 at the end on the -Z direction side. The injection nozzle 30 is fixed to the first cylindrical member 21d by press fitting, welding, or the like. 31 d of injection holes and 32 d of valve seats are provided in the injection nozzle 30 instead of the 1st cylinder member 21d. In this embodiment, the injection nozzle 30 is made of martensitic stainless steel, which is a metallic material, and is quenched to have a predetermined hardness.

As shown in FIG. 7, the housing 20d has a fifth inner surface 126 on the -Z direction side of the first inner surface 121. As shown in FIG. The fifth inner side surface 126 has a cylindrical shape centered on the central axis CL. The inner diameter of the fifth inner surface 126 is larger than the inner diameter of the first inner surface 121 . A third step surface 127 connects between the fifth inner surface 126 and the first inner surface 121 . The third step surface 127 has an annular shape centered on the central axis CL.

The inner member 90d has an extension 98 projecting from the inner peripheral end of the bottom surface 93 toward the -Z direction. The extension 98 extends from the bottom surface 93 into the fifth inner surface 126 . A biased portion 99 protruding outward in the radial direction of the extension portion 98 is provided at the end portion of the extension portion 98 on the -Z direction side. In this embodiment, the biased portion 99 is fixed to the extension portion 98 by press fitting or the like. The extension portion 98 and the biased portion 99 each have a cylindrical shape centered on the central axis CL. The shaft portion 41 passes through the inner side of the extension portion 98 and the inner side of the biased portion 99 .

A third biasing member 83 is arranged between the third step surface 127 and the biased portion 99 . The third biasing member 83 biases the biased portion 99 in the -Z direction. In this embodiment, the third biasing member 83 is configured by a coil spring that expands and contracts along the Z direction. The third biasing member 83 may be made of rubber or the like, for example. The −Z direction side end of the third biasing member 83 is in contact with the biased portion 99 , and the +Z direction side end of the third biasing member 83 is in contact with the third step surface 127 . ing.

According to the fuel injection valve 100d of this configuration, the urged portion 99 fixed to the inner member 90d is urged by the third urging member 83 in the -Z direction, and the flange portion 92 moves toward the second stepped surface 125. , the displacement of the inner member 90d in the +Z direction with respect to the housing 20d when the pressure of the fuel in the damper chamber 25 decreases is suppressed. Therefore, deterioration of the sealing performance between the flange portion 92 and the second stepped surface 125 can be suppressed, so that deterioration of the impact reduction effect of the damper chamber 25 can be suppressed.

E. Other embodiments:
(E-1) In the fuel injection valves 100 to 100c of the first to third embodiments described above, the first cylindrical member 21 of the housing 20 is provided with the injection hole 31 and the valve seat 32 . On the other hand, in the fuel injection valves 100 to 100c, like the fuel injection valve 100d of the fourth embodiment, the injection nozzle 30 is fixed to the first cylindrical member 21, and the injection hole 31 and the valve seat 32 are It may be provided in the injection nozzle 30 instead of the first cylinder member 21 .

(E-2) In the fuel injection valve 100b of the second embodiment described above, the flange portion 92b of the inner member 90b is provided with a step on the surface on the -Z direction side so that it comes into contact with the second step surface 125. An inner peripheral portion 94 and an outer peripheral portion 95 having a gap between the second stepped surface 125 are provided. On the other hand, in the fuel injection valve 100b, the flange portion 92b is not provided with a step, but the second step surface 125 is provided with a step. An outer peripheral portion 95 having a gap from the step surface 125 may be provided on the flange portion 92b.

(E-3) In the fuel injection valve 100c of the third embodiment described above, the flange portion 92 of the inner member 90c has an inner periphery contacting the second stepped surface 125 like the fuel injection valve 100b of the second embodiment. It may have a portion 94 and an outer peripheral portion 95 having a gap between it and the second stepped surface 125 . In this case, the displacement of the inner member 90c in the +Z direction with respect to the housing 20 can be suppressed more effectively.

(E-4) In the fuel injection valve 100d of the fourth embodiment described above, the flange portion 92 of the inner member 90d has an inner periphery contacting the second stepped surface 125 like the fuel injection valve 100b of the second embodiment. It may have a portion 94 and an outer peripheral portion 95 having a gap between it and the second stepped surface 125 . In this case, it is possible to more effectively suppress the displacement of the inner member 90d in the +Z direction with respect to the housing 20d. Furthermore, like the fuel injection valve 100c of the third embodiment, an elastic seal member 97 may be provided between the tubular portion 91 and the second inner side surface 122 of the housing 20d. In this case, it is possible to more effectively suppress the displacement of the inner member 90d in the +Z direction with respect to the housing 20d.

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

(E-6) In the fuel injection valves 100 to 100d of each embodiment described above, the fixed cores 60 and 60b are composed of the first fixed core member 61 and the second fixed core member 62 . On the other hand, the stationary cores 60 and 60b may be composed of the first stationary core member 61 alone.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the present disclosure. For example, the technical features in the embodiments may be appropriately replaced or combined in order to solve some or all of the above problems or achieve some or all of the above effects. is possible. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 11... Adjusting pipe, 12... Fuel introduction pipe, 13... Filter, 14... Inlet, 15... Connector, 16... Terminal, 17... Holder, 18... Cover, 20... Housing, 21... First cylindrical member, 22... Second cylindrical member 23 Third cylindrical member 24 Fourth cylindrical member 25 Damper chamber 30 Injection nozzle 31 Injection hole 32 Valve seat 40 Needle 41 Shaft 42 Valve portion 43 Enlarged diameter portion 44 Fuel passage 45 Communication hole 50 Movable core 51 First movable core member 52 Second movable core member 56 Large diameter portion 57 Small diameter portion , 60... Fixed core 61... First fixed core member 62... Second fixed core member 70... Coil 71... Bobbin 81... First biasing member 82... Second biasing member 83... Third Biasing member 90... Inner member 91... Cylindrical part 92... Flange part 93... Bottom part 94... Inner circumference part 95... Outer circumference part 96... Groove part 97... Elastic sealing member 98... Extension part , 99... biased portion 100... fuel injection valve 121... first inner side surface 122... second inner side surface 123... third inner side surface 124... first step surface 125... second step surface 126 ... fifth inner surface, 127 ... third step surface, 191 ... fourth inner surface

Claims (6)

A fuel injection valve (100, 100b, 100c, 100d),
Cylindrical housings (20, 20d) having a longitudinal direction (Z) and having nozzle holes (31, 31d) for injecting fuel provided at one end in the longitudinal direction;
a fixed core (60) fixed within the housing;
a movable core (50) arranged on the one end side of the fixed core and movable in the housing along the longitudinal direction;
a needle (40) for opening and closing the nozzle hole by moving in the housing along the longitudinal direction as the movable core moves;
a coil (70) for generating a magnetic field that moves the movable core;
with
The movable core has a large-diameter portion (56) facing the fixed core and a small-diameter portion (57) provided closer to the one end than the large-diameter portion and having an outer diameter smaller than the outer diameter of the large-diameter portion. ) and
The housing includes a first portion (122) in which the small diameter portion is movably arranged, and a second portion (123) in which the large diameter portion is movably arranged and has an inner diameter larger than that of the first portion. ) and a stepped portion (125) provided between the first portion and the second portion in the housing,
The housing has flange portions (92, 92b) in contact with the stepped portion, and has a tubular shape so as to form a gap with the first portion in a radial direction crossing the longitudinal direction. Inner members (90, 90b, 90c, 90d) are arranged,
A damper chamber (25) in which the fuel is enclosed is defined in the housing by the inner surface of the second portion, the flange portion, the small diameter portion, and the large diameter portion,
The fuel injection valve, wherein the outer surface of the large diameter portion slides on the inner surface of the second portion, and the outer surface of the small diameter portion slides on the inner surface of the inner member. A fuel injection valve according to claim 1,
The flange portion has an inner peripheral portion (94) provided on the inner portion in the radial direction, and an outer peripheral portion (95) provided on the outer portion in the radial direction from the inner peripheral portion. ,
The inner peripheral portion is in contact with the stepped portion,
A fuel injection valve, wherein a gap is provided between the stepped portion and the outer peripheral portion. A fuel injection valve according to claim 1 or claim 2,
A fuel injection valve comprising an elastic sealing member (97) disposed between said first portion and said inner member for sealing between said first portion and said inner member. The fuel injection valve according to any one of claims 1 to 3,
a biased portion (99) provided in a flange shape at the end portion of the inner member on the one end side;
a biasing member (83) biasing the biased portion toward the one end;
A fuel injection valve. The fuel injection valve according to any one of claims 1 to 4,
The fuel injection valve, wherein the fuel is gaseous fuel. The fuel injection valve according to any one of claims 1 to 5,
The fuel injection valve, wherein the fuel is hydrogen fuel.

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