JP5516140B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve that injects and supplies fuel to an internal combustion engine.

  2. Description of the Related Art Conventionally, a fuel injection valve having a configuration in which an urging member or an elastic member is provided on a valve seat side of a movable core through which a needle is inserted in order to suppress excessive bounce when the needle is seated is known. In the fuel injection valve of Patent Document 1, an elastic member that biases the movable core in the valve opening direction is provided on the valve seat side of the movable core. A biasing member that biases the needle and the movable core in the valve closing direction is provided on the side of the movable core opposite to the valve seat. In this fuel injection valve, sliding surfaces (guide surfaces) with the housing are formed at two locations in the axial direction of the needle (near the nozzle hole side end portion and in the axial direction). In addition, a sliding surface with the movable core is formed in the vicinity of the end portion on the opposite side to the nozzle hole of the needle. That is, the needle has sliding surfaces with other members in a total of three locations.

  When a load does not act uniformly on the contact surface between the elastic member and the biasing member, the movable core, and the needle, a lateral load acts on the three sliding surfaces. Thereby, there exists a possibility that the sliding resistance of a needle and a housing may deteriorate. Therefore, in the case of the fuel injection valve having such a configuration, the elastic member that biases the movable core in the valve opening direction and the biasing member that biases the needle and the movable core in the valve closing direction are designed with strict tolerances. There is a need. In addition, since the direction of the attractive force generated by the magnetic circuit is not limited to the axial direction of the movable core, a lateral load acts on the movable core during attraction. As a result, the sliding resistance between the needle and the housing may be further deteriorated.

  In the fuel injection valves described in Patent Documents 2 to 4, like the fuel injection valve in Patent Document 1 described above, a biasing member or an elastic member is provided on the valve seat side of the movable core, which is opposite to the valve seat of the movable core. A biasing member is provided on the side. The needle has sliding surfaces with the housing or the movable core at three locations in the axial direction. Therefore, also in the fuel injection valves described in Patent Documents 2 to 4, a lateral load acts on the needle for the same reason as described above, and the sliding resistance may be deteriorated. When the sliding resistance is deteriorated, fuel that is greater than or less than the required injection amount is injected from the fuel injection valve, and as a result, there is a possibility of causing a situation such as deterioration of emission and inability to comply with exhaust gas regulations.

Japanese translation of PCT publication No. 2003-502573 Special table 2003-512557 gazette JP 2007-218204 A Japanese Utility Model Publication No. 6-4367

  The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the sliding resistance while suppressing bounce when the needle is seated, and to control the fuel injection amount with high accuracy. Is to provide.

  The invention described in claim 1 includes a housing, an injection nozzle, a needle, a movable core, a coil, a fixed core, a first biasing member, and a second biasing member. The housing is formed in a cylindrical shape, and a fuel passage is formed inside. The injection nozzle has a bottom portion and a cylindrical portion. A nozzle hole and a valve seat are formed at the bottom. The cylindrical portion extends in a cylindrical shape from the outer edge end of the bottom portion and is provided so as to connect to one end portion of the housing. The needle is formed in a rod shape and is accommodated in the housing so as to be reciprocally movable. The needle has a seal part, a sliding part, and a collar part. The seal portion is formed at the end of the needle on the injection nozzle side. The sliding portion is formed at a position separated from the needle seal portion by a predetermined distance in the axial direction, and is slidable with the inner wall of the cylinder portion of the injection nozzle. The collar portion is formed so as to extend from an end portion of the needle opposite to the injection nozzle toward the inner wall of the housing. The needle opens and closes the injection hole when the seal portion is separated from the valve seat of the injection nozzle or seated on the valve seat. The movable core is formed in a cylindrical shape so that the needle is inserted inside. In the movable core, at least a part of the inner wall is slidable with the outer wall of the needle, at least a part of the outer wall is slidable with the inner wall of the housing, and one end surface in the axial direction can be in contact with the collar of the needle As shown in FIG. The coil is provided outside the housing and generates a magnetic force when electric power is supplied. The fixed core is provided inside the coil and the housing. When a magnetic force is generated in the coil, the fixed core is attracted together with the needle in the valve opening direction. The first urging member is provided so that one end thereof is in contact with the end of the needle on the flange side, and urges the needle together with the movable core in the valve closing direction. The second urging member is provided so that one end is in contact with the end surface of the movable core opposite to the collar portion, and urges the movable core together with the needle in the valve opening direction. With this configuration, excessive bounce when the needle is seated is suppressed.

In the present invention, when the needle reciprocates in the housing, there are two places where the needle and other members (housing and movable core) slide in the axial direction of the needle (the sliding portion and the movable core). (Sliding part) only. Therefore, even if a lateral load is applied to the sliding portion between the needle and the other member, the needle is compared with the conventional fuel injection valve configured to form three or more sliding portions between the needle and the other member. The total amount of sliding resistance acting can be reduced. This eliminates the need to strictly design tolerances for the first biasing member and the second biasing member. Further, since the sliding resistance of the needle is reduced, the amount of fuel injected from the fuel injection valve can be controlled with high accuracy. As a result, it is possible to effectively suppress the emission discharged from the internal combustion engine that is the fuel injection supply target.
In the present invention, since the needle is configured such that both end portions (the sliding portion side end portion and the movable core side end portion) are slidably supported, shaft shake is suppressed when reciprocating in the housing. The Therefore, the seating position of the seal part of the needle is stable.

In the first aspect of the invention, the inner wall of the movable core is formed with an inner sliding surface slidable with the outer wall of the needle. Further, an outer sliding surface that can slide with the inner wall of the housing is formed on the outer wall of the movable core. The clearance between the outer wall of the sliding part of the needle and the inner wall of the cylinder part of the injection nozzle is Ca, the clearance between the outer wall of the needle and the inner sliding surface of the movable core is Cb, and the outer sliding surface of the movable core When the clearance between the inner wall of the housing is Cc, the needle, the injection nozzle, the movable core and the housing are formed so as to satisfy the relationship Ca ≦ Cb <Cc.

  In addition, when the seal part of the needle is seated on the valve seat of the injection nozzle and the movable core is in contact with the collar part of the needle, the distance from the seal part to the inner sliding surface of the movable core is Da, and the seal part When the distance from the outer sliding surface of the movable core to Db is Db and the distance from the seal portion to the second urging member is Ds, the needle, the injection nozzle, the movable core, the second urging member, and the housing have Ds <Da ≦ Db is provided so as to satisfy the relationship.

  In this configuration, the amount of needle tilt (the degree of needle tilt relative to the housing) is defined by Ca and Cb + Cc, and Da and Db. Further, most of the lateral load caused by the needle collapse, the magnetic circuit attractive force, and the biasing force of the first biasing member and the second biasing member acts on the outer sliding surface of the movable core, and the inner sliding of the movable core. The lateral load acting on the surface is small. Further, the lateral load acting on the needle can be further reduced by arranging the acting point of the lateral load in the vicinity of the movable core that is far from the seal portion. Here, while satisfying the relationship of Ca ≦ Cb <Cc and Ds <Da ≦ Db, each value is set appropriately to suppress fuel leakage from the nozzle hole due to the needle falling, and It becomes possible to reduce sliding resistance.

In the invention according to claim 2, when the surface roughness of the inner wall of the movable core and the outer wall of the needle is Fca, and the surface roughness of the outer wall of the movable core and the inner wall of the housing is Fch, the needle, the movable core and the housing are , Fca <Fch. Therefore, the sliding resistance between the needle and the movable core is smaller than the sliding resistance between the movable core and the housing. Further, when the movable core moves while sliding on the housing, the movable core slides while a lateral load is applied to the wall surface (the outer wall of the movable core and the inner wall of the housing) having a surface roughness Fch. The sliding resistance works. Thereby, the undershoot more than necessary of the movable core can be prevented, and the responsiveness required for fuel injection can be ensured.

Sectional drawing which shows the fuel injection valve by one Embodiment of this invention. The fragmentary sectional view which shows the principal part of the fuel injection valve by one Embodiment of this invention. (A) is the sectional view on the AA line of FIG. 2, (B) is the sectional view on the BB line of FIG. 2, (C) is the sectional view on the CC line of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(One embodiment)
A fuel injection valve according to an embodiment of the present invention is shown in FIG. The fuel injection valve 10 is used in a fuel injection device for an internal combustion engine (not shown) and supplies fuel to the internal combustion engine.

The fuel injection valve 10 includes a housing 20, an injection nozzle 30, a needle 40, a movable core 50, a coil 60, a fixed core 70, a spring 80 as a first urging member, a spring 90 as a second urging member, and the like. I have.
As shown in FIG. 1, the housing 20 includes a first cylinder member 21, a second cylinder member 22, and a third cylinder member 23. The first cylinder member 21, the second cylinder member 22, and the third cylinder member 23 are all formed in a substantially cylindrical shape, and are coaxial in the order of the first cylinder member 21, the second cylinder member 22, and the third cylinder member 23. Arranged and connected to each other.

  The 1st cylinder member 21 and the 3rd cylinder member 23 are formed, for example with magnetic materials, such as ferritic stainless steel, and the magnetic stabilization process is performed. The first cylinder member 21 and the third cylinder member 23 have a relatively low hardness. On the other hand, the second cylindrical member 22 is formed of a nonmagnetic material such as austenitic stainless steel, for example. The hardness of the second cylinder member 22 is higher than the hardness of the first cylinder member 21 and the third cylinder member 23.

  The injection nozzle 30 is provided at the end of the first cylinder member 21 of the housing 20 opposite to the second cylinder member 22. The injection nozzle 30 is made of a metal such as martensitic stainless steel. The injection nozzle 30 is subjected to a quenching process so as to have a predetermined hardness.

  The injection nozzle 30 is formed in a substantially bottomed cylindrical shape and has a bottom portion 31 and a cylindrical portion 32. The bottom portion 31 closes one end portion of the cylindrical portion 32. An injection hole 311 that connects the inner wall and the outer wall is formed in the bottom 31. An annular valve seat 312 is formed on the inner wall of the bottom 31 so as to surround the nozzle hole 311. The cylinder portion 32 is connected to the first cylinder member 21 such that the outer wall is fitted to the inner wall of the first cylinder member 21. The fitting part of the cylinder part 32 and the 1st cylinder member 21 is welded.

  The needle 40 is formed in a rod shape from a metal such as martensitic stainless steel. The needle 40 is subjected to a quenching process so as to have a predetermined hardness. The hardness of the needle 40 is set substantially equal to the hardness of the injection nozzle 30.

  The needle 40 is accommodated in the housing 20 so as to be capable of reciprocating in the axial direction. A seal portion 41 that can contact the valve seat 312 is formed at the end of the needle 40 on the injection nozzle 30 side. The needle 40 has a sliding portion 42 at a position away from the seal portion 41 in the axial direction by a predetermined distance. The sliding part 42 is formed in a substantially cylindrical shape, and a part of the outer wall 421 is chamfered. The sliding portion 42 is slidable with the inner wall 321 of the cylindrical portion 32 of the injection nozzle 30 at a portion where the outer wall 421 is not chamfered. As a result, the needle 40 is guided to reciprocate at the tip of the nozzle hole 311 side. The relationship between the sliding part 42 and the cylinder part 32 will be described in detail later.

  Further, the needle 40 has a flange 43 formed to extend from the end opposite to the injection nozzle 30 toward the inner wall 24 of the housing 20. In this embodiment, the collar part 43 is formed in the substantially annular shape. The needle 40 opens and closes the nozzle hole 311 when the seal portion 41 is separated (separated) from the valve seat 312 or abuts (sits) the valve seat 312. Hereinafter, the direction in which the needle 40 is separated from the valve seat 312 is referred to as the valve opening direction, and the direction in which the needle 40 contacts the valve seat 312 is referred to as the valve closing direction. The flange 43 side of the needle 40 is formed in a hollow cylindrical shape, and a hole 44 that connects the inner wall 45 and the outer wall 46 is formed.

  The movable core 50 is formed in a substantially cylindrical shape by a magnetic material such as ferritic stainless steel. The movable core 50 is subjected to a magnetic stabilization process. The hardness of the movable core 50 is relatively low and is substantially equal to the hardness of the first cylindrical member 21 and the third cylindrical member 23 of the housing 20.

  The movable core 50 is provided inside the housing 20 so that the needle 40 is inserted inside. In the movable core 50, a part of the inner wall 51 can slide with the outer wall 46 of the needle 40, and a part of the outer wall 52 can slide with the inner wall 24 of the housing 20. Thereby, the movable core 50 can reciprocate inside the housing 20 while sliding with the needle 40 and the housing 20.

  At this time, the needle 40 can reciprocate inside the housing 20 while sliding with the movable core 50. As a result, the needle 40 is guided to reciprocate at the end opposite to the nozzle hole 311. Thus, the needle 40 is supported at two locations in the axial direction (sliding locations (sliding portion 42) with the cylindrical portion 32 of the injection nozzle 30 and sliding locations with the movable core 50), and the housing 20 Move back and forth inside. The relationship between the movable core 50, the needle 40, and the housing 20 will be described in detail later.

The movable core 50 is formed with a hole 55 that connects one end surface 53 and the other end surface 54 in the axial direction. In the present embodiment, four holes 55 are formed in the circumferential direction of the movable core 50. Since the hole 55 is formed, when the movable core 50 reciprocates in the housing 20, the pressure on the end surface 53 side of the movable core 50 and the pressure on the end surface 54 side become equal. The movement can be made smooth.
Further, the end surface 53 of the movable core 50 can be brought into contact with the end surface of the flange portion 43 of the needle 40 on the injection nozzle 30 side.

  The coil 60 is formed in a substantially cylindrical shape, and is provided so as to surround the outer side in the radial direction of the second cylindrical member 22 and the third cylindrical member 23 of the housing 20. The coil 60 generates a magnetic force when electric power is supplied.

  The fixed core 70 is formed in a substantially cylindrical shape by a magnetic material such as ferritic stainless steel. The fixed core 70 is subjected to a magnetic stabilization process. The fixed core 70 has a relatively low hardness and is approximately equal to the hardness of the movable core 50. The fixed core 70 is provided inside the coil 60 and the housing 20. The fixed core 70 and the third cylindrical member 23 of the housing 20 are welded.

  When a magnetic force is generated in the coil 60, a magnetic circuit is formed in the fixed core 70, the movable core 50, the first cylindrical member 21, and the third cylindrical member 23. Thereby, the movable core 50 is attracted to the fixed core 70. At this time, the end face 53 of the movable core 50 abuts against the collar portion 43 of the needle 40, so that the needle 40 moves together with the movable core 50 toward the fixed core 70, that is, in the valve opening direction. As a result, the seal portion 41 is separated from the valve seat 312 and the nozzle hole 311 is opened. Further, the movable core 50 is restricted from moving in the valve opening direction by the end surface 53 coming into contact with the fixed core 70.

  The spring 80 is provided so that one end is in contact with the end of the needle 40 on the flange 43 side. The other end of the spring 80 is in contact with one end of the adjusting pipe 11 that is press-fitted and fixed inside the fixed core 70. The spring 80 has a force extending in the axial direction. Thereby, the spring 80 urges the needle 40 together with the movable core 50 in the valve closing direction.

The spring 90 is provided so that one end is in contact with the bottom surface of the groove portion 541 formed on the end surface 54 of the movable core 50. The other end of the spring 90 is in contact with an annular step surface 211 formed inside the first cylindrical member 21 of the housing 20. The spring 90 has a force that extends in the axial direction. Thereby, the spring 90 urges the movable core 50 together with the needle 40 in the valve opening direction.
In this embodiment, the urging force of the spring 80 is set larger than the urging force of the spring 90. Therefore, in a state where power is not supplied to the coil 60, the seal portion 41 of the needle 40 is in contact with the valve seat 312, that is, a valve-closed state.

  A substantially cylindrical fuel introduction pipe 12 is press-fitted and welded to the end of the third cylinder member 23 opposite to the second cylinder member 22. A filter 13 is provided inside the fuel introduction pipe 12. The filter 13 collects foreign matters in the fuel that has flowed from the introduction port 14 of the fuel introduction pipe 12.

  The radially outer sides of the fuel introduction pipe 12 and the third cylinder member 23 are molded with resin. A connector 15 is formed in the mold part. The connector 15 is insert-molded with a terminal 16 for supplying power to the coil 60. A cylindrical holder 17 is provided outside the coil 60 in the radial direction so as to cover the coil 60.

  The fuel that has flowed from the introduction port 14 of the fuel introduction pipe 12 flows inside the fixed core 70, the adjusting pipe 11 and the needle 40, the hole 44, between the first tubular member 21 and the needle 40, and between the injection nozzle 30 and the needle 40. Between them and led to the nozzle hole 311. That is, a fuel passage 18 through which fuel flows is formed inside the housing 20.

  Next, the relationship between the sliding portion 42 of the needle 40 and the cylindrical portion 32 of the injection nozzle 30 and the relationship between the movable core 50, the needle 40 and the housing 20 will be described in detail with reference to FIGS. 3 (A) to 3 (C) show cross sections of each part of the fuel injection valve 10 shown in FIG. 2, but the hatches indicating the cross sections are omitted in order to avoid complication of the drawing. . 3A shows only the needle 40 and the injection nozzle 30, FIG. 3B shows only the first cylindrical member 21 (housing 20), the needle 40 and the movable core 50, and FIG. Only the second cylindrical member 22 (housing 20), the needle 40 and the movable core 50 are shown.

  As shown in FIG. 2, a substantially cylindrical inner sliding surface 511 slidable with the outer wall 46 of the needle 40 is formed on the inner wall 51 of the movable core 50 from the end surface 54 in the middle of the axial direction. . That is, a portion of the inner wall 51 of the movable core 50 other than the inner sliding surface 511 has a larger inner diameter than the inner sliding surface 511 and forms a predetermined gap with the outer wall 46 of the needle 40. Further, a substantially cylindrical outer sliding surface 521 that can slide with the inner wall 24 of the housing 20 is formed on the outer wall 52 of the movable core 50 from the end surface 53 in the middle of the axial direction. That is, a portion of the outer wall 52 of the movable core 50 other than the outer sliding surface 521 has a smaller outer diameter than the outer sliding surface 521 and forms a predetermined gap with the inner wall 24 of the housing 20.

As shown in FIG. 3A, a clearance Ca is formed between a portion of the outer wall 421 of the sliding portion 42 of the needle 40 that is not chamfered and the inner wall 321 of the cylindrical portion 32 of the injection nozzle 30. . In addition, as shown in FIG. 3B, a clearance Cb is formed between the outer wall 46 of the needle 40 and the inner sliding surface 511 of the movable core 50. Further, as shown in FIG. 3C, a clearance Cc is formed between the outer sliding surface 521 of the movable core 50 and the inner wall 24 of the housing 20. Here, the needle 40, the injection nozzle 30, the movable core 50, and the housing 20 are
Ca ≦ Cb <Cc Formula 1
It is formed to satisfy the relationship.

As shown in FIG. 2, in a state where the seal portion 41 of the needle 40 is seated (contacted) on the valve seat 312 and the end surface 53 of the movable core 50 is in contact with the flange portion 43, the seal portion 41 is moved from the movable core to the movable core 50. 50, the distance from the inner sliding surface 511 to Da, the distance from the seal portion 41 to the outer sliding surface 521 of the movable core 50 as Db, and the distance from the seal portion 41 to the spring 90 as Ds, the needle 40, injection The nozzle 30, the movable core 50, the spring 90, and the housing 20 are
Ds <Da ≦ Db Formula 2
It is provided to satisfy the relationship.

Further, in this embodiment, when the surface roughness of each of the inner wall 51 of the movable core 50 and the outer wall 46 of the needle 40 is Fca, and the surface roughness of each of the outer wall 52 of the movable core 50 and the inner wall 24 of the housing 20 is Fch, the needle 40, the movable core 50 and the housing 20,
Fca <Fch ... Formula 3
It is formed to satisfy the relationship.

Next, the operation of the fuel injection valve 10 will be described.
When the coil 60 is energized, the movable core 50 is attracted to the fixed core 70. Thereby, the needle 40 moves to the fixed core 70 side integrally with the movable core 50, and the seal portion 41 is separated from the valve seat 312. Thereby, the nozzle hole 311 will be in the open state (valve open state). The fuel flowing in from the inlet 14 of the fuel introduction pipe 12 flows through the fuel passage 18 and is injected from the injection hole 311.

  On the other hand, when the energization of the coil 60 is turned off, the needle 40 comes into contact with the valve seat 312 and closes. Therefore, fuel injection is interrupted. In the present embodiment, excessive bounce when the needle 40 is seated can be suppressed by providing the spring 90 on the injection nozzle 30 side of the movable core 50. In the present embodiment, the needle 40 is configured to be slidably supported at both end portions (the end portion on the sliding portion 42 side and the end portion on the movable core 50 side). Shaking is suppressed. Therefore, the seating position of the seal portion 41 of the needle 40 is stable.

  As described above, in the present embodiment, when the needle 40 reciprocates in the housing 20, the portion where the needle 40 and other members (the housing 20 and the movable core 50) slide is in the axial direction of the needle 40. There are only two places (sliding part 42 and sliding part with movable core 50). Therefore, compared with the conventional fuel injection valve having a configuration in which three or more sliding portions between the needle and the other member are formed even if a lateral load is applied to the sliding portion between the needle 40 and the other member. The total amount of sliding resistance acting on 40 can be reduced. This eliminates the need to strictly design the tolerances of spring 80 and spring 90. Further, since the sliding resistance of the needle 40 is reduced, the amount of fuel injected from the fuel injection valve 10 can be controlled with high accuracy. As a result, it is possible to effectively suppress the emission discharged from the internal combustion engine that is the fuel injection supply target.

  In the present embodiment, the inner wall 51 of the movable core 50 is formed with an inner sliding surface 511 that can slide with the outer wall 46 of the needle 40. An outer sliding surface 521 that can slide with the inner wall 24 of the housing 20 is formed on the outer wall 52 of the movable core 50. The clearance between the outer wall 421 of the sliding portion 42 of the needle 40 and the inner wall 321 of the cylindrical portion 32 of the injection nozzle 30 is Ca, and the clearance between the outer wall 46 of the needle 40 and the inner sliding surface 511 of the movable core 50 is If the clearance between Cb and the outer sliding surface 521 of the movable core 50 and the inner wall 24 of the housing 20 is Cc, the needle 40, the injection nozzle 30, the movable core 50, and the housing 20 have a relationship of Ca ≦ Cb <Cc. It is formed to satisfy.

  Further, in a state where the seal portion 41 of the needle 40 is seated on the valve seat 312 of the injection nozzle 30 and the movable core 50 is in contact with the flange portion 43 of the needle 40, the inner core slides from the seal portion 41. When the distance from the surface 511 is Da, the distance from the seal portion 41 to the outer sliding surface 521 of the movable core 50 is Db, and the distance from the seal portion 41 to the spring 90 is Ds, the needle 40, the injection nozzle 30, the movable core 50, the spring 90, and the housing 20 are provided so as to satisfy the relationship of Ds <Da ≦ Db.

  In this configuration, the tilting amount of the needle 40 (the degree of inclination of the needle 40 with respect to the housing 20) is defined by Ca and Cb + Cc, and Da and Db. Further, most of the lateral load generated by the needle 40 falling, the magnetic circuit attractive force, and the biasing force of the spring 80 and the spring 90 acts on the outer sliding surface 521 of the movable core 50, and the inner sliding surface 511 of the movable core 50. The lateral load acting on the surface is slight. Further, the lateral load acting on the needle 40 can be further reduced by disposing the side load acting point in the vicinity of the movable core 50 that is far from the seal portion 41. Here, while satisfying the relationship of Ca ≦ Cb <Cc and Ds <Da ≦ Db, by appropriately setting each value, it is possible to suppress fuel leakage from the nozzle hole 311 due to the needle 40 falling, The sliding resistance of the needle 40 can be reduced.

  Furthermore, in this embodiment, when the surface roughness of the inner wall 51 of the movable core 50 and the outer wall 46 of the needle 40 is Fca, and the surface roughness of the outer wall 52 of the movable core 50 and the inner wall 24 of the housing 20 is Fch, the needle 40, the movable core 50 and the housing 20 are formed so as to satisfy the relationship of Fca <Fch. Therefore, the sliding resistance between the needle 40 and the movable core 50 is smaller than the sliding resistance between the movable core 50 and the housing 20. Further, when the movable core 50 moves while sliding on the housing 20, a lateral load acts on the movable core 50 on the wall surface having the surface roughness Fch (the outer wall 52 of the movable core 50 and the inner wall 24 of the housing 20). A predetermined sliding resistance works by sliding. Thereby, the undershoot more than necessary of the movable core 50 can be prevented, and the responsiveness required for fuel injection can be ensured.

(Other embodiments)
In the above-described embodiment, the needle, the injection nozzle, the movable core, the second urging member, and the housing are formed so as to satisfy both “the relation of the above formula 1 and the above formula 2” and “the relation of the above formula 3”. The configuration provided is shown. On the other hand, in another embodiment of the present invention, the needle, the injection nozzle, the movable core, the second urging member, and the housing have the relationship of the above formula 1 and the formula 2 or the relationship of the formula 3 above. It is good also as a structure formed and provided so that one side may be satisfy | filled. In another embodiment of the present invention, the needle, the injection nozzle, the movable core, the second urging member, and the housing have any one of “the relation of the above formula 1 and the above formula 2” and “the relation of the above formula 3”. It is good also as a structure formed and provided without satisfying.

In the above-described embodiment, an example in which the housing and the injection nozzle are formed separately has been described. On the other hand, in another embodiment of the present invention, the housing and the injection nozzle may be integrally formed.
Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 10 ... Fuel injection valve 18 ... Fuel passage 20 ... Housing 21 ... 1st cylinder member (housing)
22 ... 2nd cylinder member (housing)
23 ... Third cylinder member (housing)
30 ... Injection nozzle 31 ... Bottom 311 ... Injection hole 312 ... Valve seat 32 ... Tube part 40 ... Needle 41 ... Seal part 42 ... Sliding part 43 ...鍔 part 50 ・ ・ ・ movable core 60 ・ ・ ・ coil 70 ・ ・ ・ fixed core 80 ・ ・ ・ spring (first urging member)
90 ... Spring (second biasing member)

Claims (2)

A cylindrical housing with a fuel passage formed inside;
An injection nozzle having a bottom portion in which a nozzle hole and a valve seat are formed, and a cylindrical portion extending in a cylindrical shape from an outer edge end of the bottom portion and connected to one end portion of the housing;
A seal part that is accommodated in the housing so as to be able to reciprocate, and is formed at a predetermined distance in the axial direction from the seal part that is formed at the end on the injection nozzle side, and is slidable with the inner wall of the cylinder part A sliding portion and a flange portion formed to extend from an end opposite to the injection nozzle toward the inner wall of the housing, and the seal portion is separated from the valve seat or the valve seat A rod-shaped needle that opens and closes the nozzle hole by sitting on
It is formed in a cylindrical shape so that the needle is inserted inside, at least a part of the inner wall is slidable with the outer wall of the needle, at least a part of the outer wall is slidable with the inner wall of the housing, and is axially A movable core provided so as to be able to reciprocate inside the housing so that one end face can come into contact with the flange portion;
A coil that is provided outside the housing and generates magnetic force when supplied with power;
A fixed core that is provided inside the coil and the housing and sucks the movable core together with the needle in a valve opening direction when a magnetic force is generated in the coil;
A first urging member provided so that one end abuts against an end of the needle on the flange side and urges the needle together with the movable core in a valve closing direction;
A second urging member provided with one end abutting against an end surface of the movable core opposite to the flange, and urging the movable core together with the needle in a valve opening direction ;
An inner sliding surface slidable with the outer wall of the needle is formed on the inner wall of the movable core,
An outer sliding surface slidable with the inner wall of the housing is formed on the outer wall of the movable core,
The clearance between the outer wall of the sliding portion and the inner wall of the cylindrical portion is Ca, the clearance between the outer wall of the needle and the inner sliding surface is Cb, and the outer sliding surface and the inner wall of the housing are If the clearance between them is Cc,
The needle, the injection nozzle, the movable core, and the housing are formed to satisfy a relationship of Ca ≦ Cb <Cc,
In a state where the seal portion is seated on the valve seat and the movable core is in contact with the flange portion, the distance from the seal portion to the inner sliding surface is Da, and the outer slide from the seal portion When the distance to the surface is Db and the distance from the seal portion to the second urging member is Ds,
The needle, the injection nozzle, the movable core, the second biasing member and the housing, a fuel injection valve characterized that you have provided so as to satisfy the relationship of Ds <Da ≦ Db. When the surface roughness of each of the inner wall of the movable core and the outer wall of the needle is Fca, and the surface roughness of each of the outer wall of the movable core and the inner wall of the housing is Fch,
2. The fuel injection valve according to claim 1, wherein the needle, the movable core, and the housing are formed to satisfy a relationship of Fca <Fch.

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