JP2009174398A - Fuel injection valve and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve increasing a design flexibility of injection holes, facilitating formation of injection holes, and providing desired spray shape, and also to provide a method for manufacturing the same. <P>SOLUTION: An injector (fuel injection valve) 1 includes: a cylindrical nozzle body (valve element) 30; and a needle opening and closing the injection holes 36 injecting fuel by seated on and separated from the same at an inside of the nozzle body 30. An opening part 300 is provided at a top side of the nozzle body 30, and an injection hole forming member 31 which is a separate body from the nozzle body 30 is joined to the opening part 300. The injection holes 36 providing communication between the inside and outside of the nozzle body 30 are formed by providing a plurality of injection hole forming grooves 34 in the injection hole forming member 31 facing a joint boundary surface 35 between the nozzle body 30 and the injection hole forming member 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that injects and supplies fuel to, for example, an internal combustion engine and a method for manufacturing the same.

Conventionally, various fuel injection valves that supply fuel to an internal combustion engine or the like are known (see Patent Document 1).
Examples of the fuel injection valve include a cylindrical valve body and a needle that opens and closes an injection hole for injecting fuel by being seated and separated from the inside of the valve body. In such a fuel injection valve, conventionally, a hole is formed on a member such as a valve body from one direction by using a processing method such as discharge, drilling or pressing.

JP-A-5-10223

  However, when a hole is formed from one direction using a processing method such as electric discharge, drill, or press, the shape of the hole depends on the shape of the electrode, drill, punch, etc. It is subject to the above restrictions. For this reason, the design freedom of the nozzle holes is low, and it is difficult to form the nozzle holes with complicated shapes, and a desired spray shape cannot be easily obtained.

  The present invention has been made in view of such conventional problems, and a fuel injection valve capable of increasing the design freedom of the injection hole, facilitating the formation of the injection hole, and obtaining a desired spray shape, and a method for manufacturing the same. Is to provide.

1st invention is a fuel injection valve which has a cylindrical valve body, and a needle which opens and closes a nozzle hole which injects fuel by seating and separating inside the valve body,
An opening is provided on the distal end side of the valve body, and an injection hole forming member formed separately from the valve body is joined to the opening,
By providing a plurality of nozzle hole forming grooves in the valve element and / or the nozzle hole forming member facing the joint interface between the valve element and the nozzle hole forming member, the inside and the outside of the valve element are communicated with each other. The fuel injection valve is characterized in that the injection hole is formed (claim 1).

  In the fuel injection valve of the present invention, the valve body and the nozzle hole forming member are configured separately, and the nozzle hole forming groove is provided in one or both of them. And in the joining interface of the said valve body and the said nozzle hole formation member, a nozzle hole is formed in the space divided by the said nozzle hole formation groove | channel. That is, in the present invention, the nozzle hole is formed by joining the valve body configured separately and the nozzle hole forming member. Therefore, it is possible to easily form the injection hole as compared with the case where the injection hole is formed from one direction by using a processing method such as discharge, drilling, pressing, or the like on a single member as in the prior art. it can.

Further, in the present invention, the nozzle hole forming groove may be processed in a portion facing the joint interface between the valve body and the nozzle hole forming member in order to form the nozzle hole. Therefore, it is not necessary to perform hole processing as in the prior art, and processing necessary for forming the nozzle hole can be facilitated.
Moreover, the said valve body and the said nozzle hole formation member are comprised separately. Therefore, it is possible to easily process the nozzle hole forming groove for each. Thereby, the design freedom of the nozzle hole defined by the nozzle hole forming groove can be increased, and a complicatedly shaped nozzle hole that cannot be realized by the conventional processing method can be realized. Moreover, since the position and shape of the nozzle hole can be freely changed within a processable range, a desired spray shape can be easily obtained.

  Thus, according to the present invention, it is possible to provide a fuel injection valve that can increase the design freedom of the injection hole, facilitate the formation of the injection hole, and obtain a desired spray shape.

A second invention is a method of manufacturing a fuel injection valve having a tubular valve body and a needle that opens and closes a nozzle hole for injecting fuel by being seated and separated inside the valve body,
In forming the nozzle hole, prepare the valve body having an opening on the tip side, and a nozzle hole forming member joined to the opening of the valve body,
Forming a plurality of nozzle hole forming grooves on the inner peripheral joint surface of the valve body and / or the outer peripheral joint surface of the nozzle hole forming member facing a surface that becomes a joint interface between the valve body and the nozzle hole forming member;
Thereafter, the injection hole that communicates the inside and the outside of the valve body is formed by the injection hole forming groove by joining the valve body and the injection hole forming member. It exists in a manufacturing method (Claim 7).

  In the method of manufacturing a fuel injection valve according to the present invention, in forming the nozzle hole, the inner peripheral joint surface of the valve body facing the surface that serves as a joint interface between the valve body and the nozzle hole forming member, and the jet nozzle are formed. A plurality of nozzle hole forming grooves are formed in one or both of the outer peripheral joint surfaces of the hole forming member. Thereafter, the valve body and the nozzle hole forming member are joined to form a nozzle hole in a space defined by the nozzle hole forming groove. That is, in the present invention, the nozzle hole is formed by joining the valve body configured separately and the nozzle hole forming member. Therefore, it is possible to easily form the nozzle hole as compared with the case where the hole is formed from one direction using a processing method such as electric discharge, drilling, pressing, or the like on a single member as in the prior art. it can.

Further, in the present invention, in order to form an injection hole, a portion facing a surface that becomes a bonding interface between the valve body and the injection hole forming member, that is, an inner peripheral joint surface of the valve body and the injection hole forming member. What is necessary is just to process the said nozzle hole formation groove | channel in the outer peripheral joint surface of this. Therefore, it is not necessary to perform hole processing as in the prior art, and processing necessary for forming the nozzle hole can be facilitated.
Moreover, the said valve body and the said nozzle hole formation member are comprised separately. Therefore, it is possible to easily process the nozzle hole forming groove for each. Thereby, the design freedom of the nozzle hole defined by the nozzle hole forming groove can be increased, and a complicatedly shaped nozzle hole that cannot be realized by the conventional processing method can be formed. Moreover, since the position and shape of the nozzle hole forming groove can be freely changed within a processable range, the nozzle hole can be formed so as to obtain a desired spray shape.

  As described above, according to the manufacturing method of the present invention, it is possible to manufacture a fuel injection valve that can increase the design freedom of the injection hole, facilitate the formation of the injection hole, and obtain a desired spray shape.

In the first invention, it is preferable that the nozzle hole forming grooves are provided at equal intervals in the circumferential direction.
In this case, the fuel can be uniformly injected in each direction, and for example, a spray shape such as a hollow cone shape can be easily formed with high accuracy.
In addition, the position, shape, etc. of the nozzle hole forming groove can be variously changed depending on the position, shape, etc. of the nozzle hole to be formed.

The nozzle hole forming groove is preferably provided only in the nozzle hole forming member.
In this case, since it suffices to perform processing only on the nozzle hole forming member, the processing necessary for forming the nozzle holes becomes easier, and productivity can be improved.
As described above, the injection hole forming groove can be provided only in the valve body, or can be provided in both the valve body and the injection hole forming member.

In addition, the joint interface between the valve body and the nozzle hole forming member is preferably a conical surface, an elliptical cone surface, or a polygonal pyramid surface whose diameter increases as it approaches the tip side of the valve body. ).
In this case, the contact position between the valve body and the nozzle hole forming member can be easily determined, and the accuracy of the nozzle hole arrangement position can be increased.

The cross-sectional area of the nozzle hole is preferably gradually increased from the upstream side to the downstream side.
In this case, the flow rate of the fuel passing through the nozzle hole can be prevented from being impaired. Therefore, an effect of suppressing deposit accumulation in the nozzle hole can be obtained.
In addition, it can also be set as the structure from which the cross-sectional area of the said nozzle hole becomes small gradually from the upstream to the downstream, or the structure same from the upstream to the downstream.

Further, it is preferable that the adjacent nozzle holes communicate with each other at the downstream side openings.
In this case, the adjacent nozzle holes formed independently on the upstream side communicate with each other in the circumferential direction on the downstream side, and are connected over the entire circumference. Therefore, a spray shape such as a holocorn shape can be easily formed with high accuracy by the fuel injected from the nozzle hole.
In addition, the said adjacent nozzle hole can also be set as the structure by which the opening part of an upstream is connected mutually. That is, it is possible to adopt a configuration in which the adjacent nozzle holes formed independently on the downstream side communicate with each other in the circumferential direction on the upstream side. In this case, the fuel can be easily introduced into the nozzle hole.

  Further, when the adjacent nozzle holes are independently formed on the downstream side, the adjacent nozzle holes are independently formed on the upstream side or communicated with each other. In either case, the openings on the downstream side of the nozzle holes are arranged at intervals. Therefore, a space in which fuel is not injected is formed between the adjacent nozzle holes. Thereby, introduction of air is promoted with respect to the fuel spray injected from the nozzle hole, and fuel atomization and spray rolling can be promoted.

In the second invention, various known processing methods can be used as the method for forming the nozzle hole forming groove. For example, processing methods such as cutting and polishing can be used, and these processing methods can be used in combination.
Moreover, as a method of joining the said valve body and the said nozzle hole formation member, various well-known joining methods can be used. For example, by performing metal plating such as copper on the bonding interface of the base material to be joined, heating the contact portion to mutually diffuse the metal and joining, or melting the base materials to be joined together by high temperature plasma A method such as plasma bonding for bonding may be used.

Example 1
A fuel injection valve (hereinafter referred to as an injector) according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the injector 1 of this example is applied to, for example, a direct injection gasoline engine. The injector 1 is mounted on an engine head (not shown). The injector 1 is not limited to a direct-injection gasoline engine, but can also be applied to a premixed gasoline engine, a diesel engine, or the like.
Moreover, in the injector 1 of this example, let the side in which the nozzle hole 36 is provided be a front end side, and let the opposite side be a rear end side.

  As shown in FIG. 1, the injector 1 includes a cylindrical pipe 10. The pipe 10 includes a first magnetic part 11, a nonmagnetic part 12, and a second magnetic part 13, and is integrally connected by laser welding or the like, for example. The first magnetic part 11 and the second magnetic part 13 are made of a magnetic material. The nonmagnetic portion 12 is made of a nonmagnetic material and prevents a magnetic short circuit between the first magnetic portion 11 and the second magnetic portion 13.

  A fixed core 21 is accommodated on the inner peripheral side of the pipe 10 by press-fitting. The fixed core 21 is formed in a cylindrical shape from a magnetic material. An adjusting pipe 28 and a spring 26 described later are accommodated on the inner peripheral side of the fixed core 21.

  An external connector 19 is press-fitted into the rear end portion 102 of the pipe 10. The external connector 19 has a fuel inlet 191 formed at the rear end. Fuel is supplied to the fuel inlet 191 from a fuel tank by a fuel pump (not shown). The fuel supplied to the fuel inlet 191 flows into the inner peripheral side of the pipe 10 via the filter member 18 provided inside the external connector 19. The filter member 18 removes foreign matters contained in the fuel.

  A nozzle holder 14 is disposed on the tip side of the pipe 10. The nozzle holder 14 is formed in a cylindrical shape from a magnetic material. The nozzle holder 14 is joined to the tip portion 101 of the pipe 10. A nozzle body (valve element) 30 is accommodated in the tip portion 141 of the nozzle holder 14. The nozzle body 30 is formed in a cylindrical shape, and is fixed to the tip portion 141 of the nozzle holder 14 by, for example, press fitting, welding, or the like. The nozzle body 30 has a valve seat 304 on a conical inner peripheral surface whose inner diameter decreases as it approaches the tip.

  A movable core 22 is accommodated on the inner peripheral side of the pipe 10. The movable core 22 is formed in a cylindrical shape from a magnetic material. The movable core 22 is disposed to face the fixed core 21 in the axial direction, and is configured to be attracted to the fixed core 21 by a magnetic attraction force generated between the movable core 22 and the fixed core 21 by energizing a coil 51 described later. ing. The movable core 22 can reciprocate in the axial direction on the inner peripheral side of the pipe 10.

  Further, on the inner peripheral side of the pipe 10, the nozzle holder 14, and the nozzle body 30, a needle 40 is accommodated so as to be capable of reciprocating in the axial direction. The needle 40 is arranged coaxially with the nozzle body 30. The needle 40 has a rear end joined to the movable core 22. Therefore, the movable core 22 and the needle 40 can reciprocate in the axial direction integrally. The needle 40 has a seal portion 42 at the tip. The seal portion 42 can be seated on the valve seat 304 of the nozzle body 30.

  The needle 40 is in contact with the spring 26 that is an elastic member at the rear end. One end portion of the spring 26 is in contact with the rear end portion of the needle 40, and the other end portion is in contact with the adjusting pipe 28. The elastic member is not limited to a spring, and for example, a leaf spring or a gas or liquid damper can be applied.

  Moreover, the adjusting pipe 28 is press-fitted into the inner peripheral side of the fixed core 21 as described above. By adjusting the press-fitting amount of the adjusting pipe 28, the load of the spring 26 is adjusted. The spring 26 has a force that extends in the axial direction. Therefore, the integral needle 40 and the movable core 22 are pressed by the spring 26 in the direction in which the seal portion 42 is seated on the valve seat 304.

As shown in the figure, a coil assembly 50 is disposed on the outer peripheral side of the pipe 10. The coil assembly 50 is integrally composed of a coil 51, a mold resin 52 and an electrical connector 53.
The coil 51 is covered with a mold resin 52. The coil 51 is formed in a cylindrical shape in a state where the outer peripheral side and the inner peripheral side are covered with the mold resin 52. The coil 51 continuously covers the outer peripheral side of the pipe 10 in the circumferential direction. The coil 51 is connected to the terminal 55 of the electrical connector 53 by a wiring member 54. Further, the mold resin 52 and the electrical connector 53 are integrally formed of resin.

  A housing plate 15 is disposed on the outer peripheral side and the rear end side of the coil 51. The housing plate 15 is formed in a cylindrical shape from a magnetic material, and is disposed so as to cover the outer peripheral side and the rear end side of the coil 51. The housing plate 15 holds the coil 51 covered with the mold resin 52 between the pipe 10 and the housing plate 15.

As shown in FIGS. 2 to 5, the injector 1 of the present example is provided with an opening 300 on the tip side of the nozzle body 30, and the nozzle 300 is formed separately from the nozzle body 30 in the opening 300. Are joined. Further, the injector 1 communicates the inside and outside of the nozzle body 30 by providing a plurality of nozzle hole forming grooves 34 in the nozzle hole forming member 31 facing the joint interface 35 between the nozzle body 30 and the nozzle hole forming member 31. A nozzle hole 36 is formed.
This will be described in detail below.

  As shown in FIG. 2, the nozzle body 30 has an opening 300 at its tip 301. Further, the nozzle body 30 has an inner peripheral joint surface 302 whose inner diameter increases on the inner peripheral surface of the tip portion 301 as it approaches the tip side of the nozzle body 30. The inner peripheral joint surface 302 is a conical surface. The inner peripheral joint surface 302 and the valve seat 304 are connected by a connecting inner peripheral surface 303 having the same diameter in the axial direction.

As shown in FIGS. 3 and 4, the nozzle hole forming member 31 has a conical joint 32 whose outer diameter decreases as it approaches the rear end side (rear end surface 312), and as it approaches the front end side (front end surface 311). And a conical non-joining portion 33 having a small outer diameter.
As shown in FIGS. 3 to 5, the joint portion 32 has an outer peripheral joint surface 321 on the outer peripheral surface thereof. The outer peripheral joint surface 321 is a conical surface. A plurality of nozzle hole forming grooves 34 are provided in the outer peripheral joint surface 321 in the radial direction. The nozzle hole forming groove 34 is gradually widened from the rear end 323 to the front end 322 of the outer peripheral joint surface 321 and has a large cross-sectional area, and has a shape in which a part of a cone is cut out from the outer peripheral joint surface 321. ing. Four nozzle hole forming grooves 34 are provided at equal intervals in the circumferential direction on the outer peripheral joint surface 321.

  As shown in FIG. 2, the nozzle hole forming member 31 is joined to the opening 300 of the nozzle body 30 so as to close the opening 300. The nozzle hole forming member 31 is bonded by bringing the outer peripheral bonding surface 321 of the bonding portion 32 into contact with the inner peripheral bonding surface 302 of the nozzle body 30. By joining the inner peripheral surface 302 of the nozzle body 30 and the outer peripheral joint surface 321 of the joint portion 32 of the nozzle hole forming member 31, the space defined by the nozzle hole forming groove 34 at the joint interface 35 is disposed inside the nozzle body 30. A nozzle hole 36 communicating with the outside is formed. Note that the bonding interface 35 in this example is a conical surface.

  As shown in the figure, the injection hole 36 is formed from the rear end face 312 of the injection hole forming member 31 to the outer peripheral non-joint surface 331 that is the outer peripheral face of the non-joint portion 33. Therefore, the nozzle hole inlet 361 is formed on the rear end surface 312 of the nozzle hole forming member 31, and the nozzle hole outlet 362 is formed on the outer peripheral non-bonding surface 331 of the non-bonding portion 33. The nozzle hole 36 has the same shape as the nozzle hole forming groove 34. For this reason, the cross-sectional area of the injection hole 36 gradually increases from the injection hole inlet 361 to the injection hole outlet 362. Four injection holes 36 are formed at equal intervals in the circumferential direction at the bonding interface 35.

Next, a method for manufacturing the injector 1 having the above configuration will be briefly described.
In this example, when forming the nozzle hole 36, first, the nozzle body 30 having the opening 300 on the tip side and the nozzle hole forming member 31 joined to the opening 300 of the nozzle body 30 were prepared.
Then, a plurality of nozzle hole forming grooves 34 were formed on the outer peripheral joint surface 321 of the joint portion 32 of the nozzle hole forming member 31 facing the surface serving as the joint interface 35 between the nozzle body 30 and the nozzle hole forming member 31. In this example, the nozzle hole forming groove 34 is formed by performing cutting, polishing or a combination thereof.

Thereafter, the nozzle body 30 and the nozzle hole forming member 31 were joined to form the nozzle hole 36 that communicates the inside and the outside of the nozzle body 30 by the nozzle hole forming groove 34.
In this example, copper plating is performed on the outer peripheral joint surface 321 of the joint portion 32 of the nozzle hole forming member 31, and the inner peripheral joint surface 302 of the nozzle body 30 is contacted and heated, and copper is mutually diffused at the contact portion and joined. The nozzle body 30 and the nozzle hole forming member 31 were joined by diffusion joining. In addition, it can replace with diffusion bonding and can also perform by the plasma joining joined by fuse | melting the base materials to join by high temperature plasma.

Next, the operation of the injector 1 having the above configuration will be described.
When energization of the coil 51 is stopped, no magnetic attractive force is generated between the fixed core 21 and the movable core 22. Therefore, the movable core 22 is separated from the fixed core 21 by the pressing force of the spring 26. As a result, when energization of the coil 51 is stopped, the seal portion 42 of the needle 40 is seated on the valve seat 304 (valve closed state). Therefore, fuel is not injected from the injection hole 36.

  When the coil 51 is energized, magnetic flux flows through the magnetic circuit formed in the nozzle holder 14, the pipe 10, the movable core 22, the fixed core 21, and the housing plate 15 due to the magnetic field generated in the coil 51. Therefore, a magnetic attractive force is generated between the fixed core 21 and the movable core 22 that are separated from each other. Thereby, when the magnetic attraction force generated between the fixed core 21 and the movable core 22 becomes larger than the pressing force of the spring 26, the integral movable core 22 and the needle 40 move in the direction of the fixed core 21. As a result, the seal portion 42 of the needle 40 is separated from the valve seat 304 (valve open state).

  The fuel flowing in from the fuel inlet 191 of the external connector 19 passes through the filter member 18 and the inner peripheral side of the pipe 10, that is, the inner peripheral side of the adjusting pipe 28, the inner peripheral side of the fixed core 21, and the inner peripheral side of the movable core 22. Via. The fuel that has flowed into the needle 40 from the inner peripheral side of the movable core 22 passes between the pipe 10 and the needle 40 through the fuel hole 45 that communicates the inside and the outside of the needle 40, and the needle 40, the nozzle holder 14, and the like. Flows in between. Then, it passes through between the needle 40 separated from the valve seat 304 and the nozzle body 30, and is injected from the injection hole 36 formed at the joining interface 35 between the nozzle body 30 and the injection hole forming member 31.

  When energization of the coil 51 is stopped, the magnetic attractive force between the fixed core 21 and the movable core 22 disappears. Thereby, the integral movable core 22 and the needle 40 are moved in the opposite direction to the fixed core 21 by the pressing force of the spring 26. As a result, the seal portion 42 of the needle 40 is again seated on the valve seat 304 (closed state). Therefore, the fuel injection from the nozzle hole 36 is completed.

Next, the effect in the injector 1 of this example is demonstrated.
In the injector 1 of this example, the nozzle body 30 and the injection hole forming member 31 are formed separately, and the injection hole forming groove 34 is provided in one of them (the injection hole forming member 31). An injection hole 36 is formed in a space defined by the injection hole forming groove 34 at the joint interface 35 between the nozzle body 30 and the injection hole forming member 31. That is, in this example, the nozzle hole 36 is formed by joining the nozzle body 30 and the nozzle hole forming member 31 which are configured separately. Therefore, the injection hole 36 is easily formed as compared with the case where the injection hole 36 is formed by performing hole processing from one direction using a processing method such as discharge, drilling, pressing, or the like on a single member as in the prior art. be able to.

Moreover, in this example, in order to form the nozzle hole 36, the nozzle hole is formed in a portion facing the bonding interface 35 between the nozzle body 30 and the nozzle hole forming member 31 (the outer peripheral bonding surface 321 of the bonding portion 32 of the nozzle hole forming member 31). The formation groove 34 may be processed. Therefore, it is not necessary to perform hole processing as in the prior art, and processing necessary to form the injection hole 36 can be facilitated.
The nozzle body 30 and the nozzle hole forming member 31 are configured separately. Therefore, the nozzle hole forming groove 34 can be easily processed with respect to the nozzle hole forming member 31, and the nozzle hole forming grooves 34 having various shapes can be formed. Thereby, the design freedom of the nozzle hole 36 defined by the nozzle hole forming groove 34 can be increased, and the complicatedly shaped nozzle hole 36 that cannot be realized by the conventional processing method can be realized. Moreover, since the position and shape of the injection hole 36 can be freely changed within a processable range, a desired spray shape can be easily obtained.

In this example, the nozzle hole forming grooves 34 are provided at equal intervals in the circumferential direction. Therefore, fuel can be injected uniformly in each direction, and for example, a spray shape such as a hollow cone shape can be easily formed with high accuracy.
Further, the joining interface 35 between the nozzle body 30 and the nozzle hole forming member 31 is a conical surface. Therefore, the contact position between the nozzle body 30 and the injection hole forming member 31 can be easily determined, and the accuracy of the arrangement position of the injection hole 36 can be increased.
The cross-sectional area of the injection hole 36 gradually increases from the upstream side to the downstream side. Therefore, the flow rate of the fuel passing through the injection hole 36 can be prevented from being impaired. Thereby, the effect which suppresses the accumulation of the deposit in the nozzle hole 36 is acquired.

  Thus, according to this example, it is possible to provide a fuel injection valve (injector) that can increase the design freedom of the injection hole, facilitate the formation of the injection hole, and obtain a desired spray shape.

  In this example, the cross-sectional area of the injection hole 36 is gradually increased from the upstream side to the downstream side, but the cross-sectional area of the injection hole 36 is gradually decreased from the upstream side to the downstream side. (See FIG. 6), or the same configuration from the upstream side to the downstream side.

(Example 2)
In this example, as shown in FIGS. 7 and 8, the configuration of the injection hole forming member 31 is changed.
In FIG. 7, the nozzle hole forming member 31 has six nozzle hole forming grooves 34 on the outer peripheral joint surface 321 of the joint portion 32. The nozzle hole forming grooves 34 are provided at equal intervals in the circumferential direction on the outer peripheral joint surface 321. In the state where the nozzle hole forming member 31 is assembled to the nozzle body 30, the adjacent nozzle holes 36 are not connected to each other on the downstream side (the nozzle hole outlet 362), and are arranged at intervals. . Note that the upstream side opening (injection hole inlet 361) is not in communication with each other and is formed independently.
Other configurations are the same as those in the first embodiment.

In this case, as shown in the figure, there is a portion where the fuel injection region 360 of each injection hole 36 does not overlap with the fuel injection region 360 of the adjacent injection hole 36. That is, a space 37 in which fuel is not injected is formed between adjacent nozzle holes 36. The space 37 formed between the nozzle holes 36 facilitates the introduction of air to the fuel spray injected from the nozzle holes 36, and can promote atomization of the fuel and the rising of the spray.
The other functions and effects are the same as those of the first embodiment.

In FIG. 8, the nozzle hole forming member 31 has six nozzle hole forming grooves 34 on the outer peripheral joint surface 321 of the joint portion 32. The nozzle hole forming grooves 34 are provided at equal intervals in the circumferential direction on the outer peripheral joint surface 321. In a state where the nozzle hole forming member 31 is assembled to the nozzle body 30, the adjacent nozzle holes 36 are in communication with the downstream opening (the nozzle hole outlet 362). The upstream side opening (injection hole inlet 361) does not communicate with each other and is formed independently.
Other configurations are the same as those in the first embodiment.

In this case, as shown in the figure, each nozzle hole 36 is connected over the entire circumference on the downstream side. That is, a portion where the fuel injection regions 360 of the adjacent injection holes 36 do not overlap does not occur. Therefore, the fuel can be sprayed from the injection hole 36 into the shape of a holographic cone with high accuracy.
The other functions and effects are the same as those of the first embodiment.

  In addition, as a modification of FIG. 8, it is possible to adopt a configuration in which the upstream opening (the injection hole inlet 361) communicates with each other in the adjacent injection holes 36. At this time, the openings on the downstream side (the nozzle hole outlet 362) do not communicate with each other and are formed independently. In this case, the fuel can be easily introduced into the injection hole 36.

  7 and 8 show a state where the nozzle hole forming member 31 is assembled to the nozzle body 30. FIG. Therefore, the opening 300 in which the nozzle hole forming member 31 is disposed, the nozzle hole 36 formed by joining the nozzle body 30 and the nozzle hole forming member 31, the nozzle hole inlet 361, and the nozzle hole outlet 362 are illustrated.

(Example 3)
In this example, as shown in FIGS. 9 and 10, the configuration of the nozzle hole forming groove 34 (the nozzle hole 36) is changed.
In FIG. 9, the nozzle hole forming groove 34 is provided only in the nozzle body 30. That is, the nozzle hole forming groove 34 is provided on the inner peripheral joint surface 302 of the nozzle body 30. In a state where the nozzle hole forming member 31 is bonded to the nozzle body 30, the nozzle hole 36 is formed in a space defined by the nozzle hole forming groove 34 provided in the nozzle body 30 at the bonding interface 35 between them.
The other configuration is the same as that of the first embodiment, and has the same operation and effect.

In FIG. 10, the nozzle hole forming groove 34 is provided in both the nozzle body 30 and the nozzle hole forming member 31. That is, the nozzle hole forming groove 34 is provided on both the inner peripheral joint surface 302 of the nozzle body 30 and the outer peripheral joint surface 321 of the joint portion 32 of the nozzle hole forming member 31. In the state where the nozzle hole forming member 31 is bonded to the nozzle body 30, the nozzle hole 36 is formed in the space defined by the nozzle hole forming groove 34 provided in both at the bonding interface 35 between them.
The other configuration is the same as that of the first embodiment, and has the same operation and effect.

Explanatory drawing which shows the structure of the injector in Example 1. FIG. Sectional drawing which expanded the front-end | tip part of the injector in Example 1. FIG. FIG. 3 is a perspective view showing an injection hole forming member in Example 1. The figure which looked at the nozzle hole formation member in Example 1 from the side. The figure which looked at the nozzle hole formation member in Example 1 from the rear end side. The figure which looked at the nozzle hole formation member in Example 1 from the rear end side. The figure which looked at the nozzle hole formation member in Example 2 from the rear end side. The figure which looked at the nozzle hole formation member in Example 2 from the rear end side. Sectional drawing which expanded the front-end | tip part of the injector in Example 3. FIG. Sectional drawing which expanded the front-end | tip part of the injector in Example 3. FIG.

Explanation of symbols

1 Injector (fuel injection valve)
30 Nozzle body (valve)
300 opening 31 injection hole forming member 34 injection hole forming groove 35 joint interface 36 injection hole

Claims (7)

A fuel injection valve having a cylindrical valve body and a needle for opening and closing a nozzle hole for injecting fuel by being seated and separated from the inside of the valve body,
An opening is provided on the distal end side of the valve body, and an injection hole forming member formed separately from the valve body is joined to the opening,
By providing a plurality of nozzle hole forming grooves in the valve element and / or the nozzle hole forming member facing the joint interface between the valve element and the nozzle hole forming member, the inside and the outside of the valve element are communicated with each other. A fuel injection valve, wherein the injection hole is formed.   2. The fuel injection valve according to claim 1, wherein the nozzle hole forming grooves are provided at equal intervals in the circumferential direction.   3. The fuel injection valve according to claim 1, wherein the nozzle hole forming groove is provided only in the nozzle hole forming member.   4. The conical surface, elliptical conical surface, or polygonal pyramid whose diameter increases as the joint interface between the valve body and the injection hole forming member approaches the distal end side of the valve body according to claim 1. A fuel injection valve characterized by being a surface.   5. The fuel injection valve according to claim 1, wherein a cross-sectional area of the nozzle hole is gradually increased from the upstream side to the downstream side. 6.   The fuel injection valve according to any one of claims 1 to 5, wherein the adjacent nozzle holes have downstream openings communicating with each other. A method of manufacturing a fuel injection valve having a cylindrical valve body and a needle that opens and closes a nozzle hole for injecting fuel by being seated and separated from the inside of the valve body,
In forming the nozzle hole, prepare the valve body having an opening on the tip side, and a nozzle hole forming member joined to the opening of the valve body,
Forming a plurality of nozzle hole forming grooves on the inner peripheral joint surface of the valve body and / or the outer peripheral joint surface of the nozzle hole forming member facing a surface that becomes a joint interface between the valve body and the nozzle hole forming member;
Thereafter, the injection hole that communicates the inside and the outside of the valve body is formed by the injection hole forming groove by joining the valve body and the injection hole forming member. Production method.

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