JP2008274792A - Fluid injection nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection nozzle 1, in which sealability is improved without increasing abrasion of a seat, supply of fluid flowing a very small clearance is facilitated to provide good atomization of spray, and accuracy in injection of very small amount is improved. <P>SOLUTION: A seal part of two point seal structure having a first seal part S1 upstream of an opening part of a first injection hole 7 formed to a conic valve seat 22 of a nozzle body 9 and a second seal part S2 downstream of the opening part, is provided. Between the first seal part S1 and the second seal part S2, provided is an abutting part A in which a first valve element 10 and a valve seal 22 are abutted in a planar manner when the first valve element 10 and the valve seat 22 are abutted to block a flow of high-pressure fluid into the first injection hole 7. At least in one of a portion between the opening part and the first seal part S1, and a portion between the opening part and the second seal part S2, a reservoir chamber Q storing the high-pressure fluid therein, and a communication passage R flowing the high-pressure fluid between the reservoir chamber Q and the opening part through the abutting part A, are provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid ejection nozzle.

[Conventional technology]
The fluid injection nozzle performs atomization supply by atomizing a fluid and is used in various industrial fields. In the field of automobiles, it is widely applied to a fuel injection valve of a fuel injection device of an internal combustion engine that uses fuel as a fluid. In recent years, exhaust gas regulations of internal combustion engines (hereinafter referred to as engines) have been strengthened year by year for environmental improvement, and development has been promoted with the problem of reducing PM emissions, NOx emissions, and CO2 emissions.

  In particular, for diesel engines, measures to increase the pressure of the injection fluid and multistage injection are being investigated for this problem. In response to multistage injection, the fuel injection valve shortens the multistage injection interval by improving the responsiveness of the on-off valve. Further, there is a demand for improvement in precision control technology such as improvement in the accuracy of minute amount injection used in multistage injection.

  Conventionally, in a diesel engine, a variable injection hole type fuel injection nozzle has been used in order to cope with atomization of the spray in a low rotation range of the engine and a large amount of short-term injection in a high rotation range. The variable nozzle type fuel injection nozzle has a plurality of nozzle holes that are sequentially opened at least in two stages, and the number of nozzle holes that can be opened can be changed according to the injection amount.

  As shown in FIG. 7, the conventional variable injection hole type fuel injection nozzle 110 (hereinafter referred to as the nozzle 110) has a nozzle body 103 having a guide hole 123 formed therein, and the guide hole 123. The end of the combustion chamber is limited by a valve seat 122, at least one injection hole 101 is formed in the valve seat 122, and further has a valve hollow needle 104, and the valve hollow needle 104 is guided. The end portion 130 of the valve hollow needle 104 facing the valve seat 122 forms a valve seal surface 128 that can be lifted in the longitudinal direction within the hole 123. A first seal region 124 on the upstream side of the hole 101 and a second seal region 125 on the downstream side are formed. When the valve hollow needle 104 abuts (sits) the valve seat 122, the first and second seal regions 1 4, 125 and the valve seal surface 128 form seal portions S11, S12 between the valve seat 122 to form a two-point seal structure, and block high-pressure fuel from flowing into the nozzle hole 101. (For example, see Patent Documents 1 and 2).

  In the nozzle 110 disclosed in Patent Document 1, as shown in FIG. 7, three conical surfaces are formed on the valve seal surface 128, and conical angles toward the apexes of the conical surfaces are formed at different angles. An edge is formed at the transition of the conical surface. This edge portion constitutes the first and second seal regions 124 and 125, and an annular annular groove structure disclosed in, for example, Patent Document 2 is provided between the first and second seal regions 124 and 125. The contact portion is formed in the shape of a conical surface, the contact portion forms the valve seal surface 128, reduces the seal surface pressure of the valve seal surface 128, and suppresses to a predetermined seal surface pressure, While obtaining a seal, excessive wear is prevented.

[Problems with conventional technology]
However, although it is easy to suppress seat wear by lowering the seal surface pressure, the surface seal structure in which the nozzle hole 101 is closed by the valve seal surface 128 causes a minute gap when the valve hollow needle 104 is initially lifted. The flow resistance of the fuel passing therethrough increases, and as a result, the fuel pressure flowing into the nozzle hole 101 is lowered, and the high-pressure fuel flowing into the opening becomes insufficient, and good atomization cannot be obtained. There's a problem.
JP 2005-530091 Gazette JP-T-2006-505745

  A first seal region on the upstream side of the injection hole and a second seal region on the downstream side of the nozzle hole with the edge portion formed at the transition portion of the conical surface having a different cone angle at the end of the valve body contacting the valve seat In a fluid injection nozzle having a two-point seal structure that forms and seals, in order to suppress seat wear over time, a valve seal surface including a surface-shaped contact portion that closes the nozzle hole is provided with a first seal area and a second seal area. When it is formed between the seal area and abuts against the nozzle hole to reduce the seal surface pressure, the flow resistance of the fluid passing through the minute gap increases at the time of minute lift at the initial stage of valve opening. Insufficient high-pressure fluid flows into the tank, and satisfactory atomization is not obtained. Therefore, a fluid injection nozzle that can suppress the wear of the seat while ensuring high sealing performance, and at the time of micro lift at the initial stage of valve opening, can obtain good atomization of the spray and improve the accuracy of micro injection. Providing becomes an issue.

  The present invention has been made in order to solve the above-mentioned problems, and improves the sealing characteristics without deteriorating the seat wear. Further, the present invention provides a fluid supply that flows through a minute gap at the time of minute lift in the initial stage of valve opening. An object of the present invention is to provide a fluid ejection nozzle that can easily obtain a good atomization and can improve the accuracy when a minute amount is ejected.

[Means of Claim 1]
According to the first aspect of the present invention, the nozzle body includes a nozzle body in which the nozzle hole is formed, and a valve body that is movably accommodated inside the nozzle body, and the valve body and the nozzle body are brought into contact with or separated from each other. And a first seal portion provided on the upstream side of the opening of the nozzle hole, having a function as a seal portion that opens and closes the nozzle hole and blocks or allows high-pressure fluid to flow into the nozzle hole. In a fluid ejection nozzle having a second seal portion provided on the downstream side of the opening, when the valve body abuts on the nozzle body, the valve body and the nozzle body are between the first seal portion and the second seal portion. Has a contact portion that contacts the surface of the nozzle body, and when the valve body contacts the nozzle body, a storage chamber for storing high-pressure fluid is provided between the first seal portion and the opening, or 2 Formed on at least one of the seal part and the opening part It is characterized.

  Thereby, by providing the contact portion in which the valve body and the nozzle body contact in a planar shape, the seal surface pressure can be reduced, and the first seal portion and the second seal portion can be suppressed to a predetermined seal surface pressure value. Sufficient sealing performance can be ensured, and promotion of seat wear can be suppressed. Furthermore, since the fluid flow to the nozzle hole is facilitated by providing the storage chamber, it is possible to obtain a good atomization at the time of micro lift at the initial stage of valve opening, and it is possible to improve the accuracy at the time of micro quantity injection.

[Means of claim 2]
According to the means described in claim 2, when the valve body and the nozzle body are initially contacted, the contact portion is formed with a slight gap between the contact portion and the nozzle body, Thereafter, when the valve body further approaches the nozzle body and stably contacts the nozzle body, the valve body and the nozzle body are formed so as to contact each other in a planar shape.

  As a result, the seal surface pressure can be reduced at the abutting portion that abuts in a planar shape, while the first seal portion and the second seal portion are allowed to undergo microscopic elastic deformation, and thus do not lead to seat wear. It becomes easy to secure a predetermined surface pressure value, and the sealing characteristics can be further improved.

[Means of claim 3]
According to the means described in claim 3, the storage chamber includes an upstream storage chamber provided between the first seal portion and the opening, and a downstream storage chamber provided between the second seal portion and the opening. It is characterized by having.
As a result, the high pressure fluid that flows in through the minute gap between the first seal portion and the second seal portion can supply the fluid stored in both the upstream storage chamber and the downstream storage chamber at the time of the micro lift in the initial stage of valve opening. The fluid flow to the nozzle hole is facilitated, and good atomization is more easily obtained.

[Means of claim 4]
According to the means described in claim 4, the storage volume of the upstream storage chamber and the storage volume of the downstream storage chamber are set to substantially the same volume.
As a result, the occurrence of uneven injection pressure at the initial stage of injection can be suppressed, so that the fluid flow from the upstream and downstream can be easily equalized, and the fluid flow is less likely to be disturbed. And the accuracy at the time of minute amount injection can be improved.

[Means of claim 5]
According to the means of the fifth aspect, when the valve body and the nozzle body are brought into contact with each other so as to block the high pressure fluid from flowing into the nozzle hole, the contact between the storage chamber and the opening is made through the contact portion. It has a communication path through which a high-pressure fluid flows.

  As a result, the high pressure fluid that flows in through the minute gap between the first seal portion and the second seal portion at the time of the minute lift in the initial stage of the valve opening is stored because the communication area between the storage chamber and the opening is expanded. A large amount of fluid can be supplied immediately and a rapid fluid flow to the nozzle hole is possible. Therefore, it becomes easier to obtain good atomization of the spray, and accuracy at the time of injection of a minute amount can be improved.

[Means of claim 6]
According to the means described in claim 6, a plurality of sets of abutting portions and communication paths are alternately arranged adjacent to each other.
As a result, the atomization of the fluid from the plurality of nozzle holes arranged in the circumferential direction can be made uniform and good, and the variation in the injection amount can be kept small, and the accuracy at the time of minute injection can be improved. It becomes possible.

[Means of Claim 7]
According to the means described in claim 7, the communication path is provided to be inclined with respect to the axial line of the valve body.
Thereby, the processing man-hour of the communicating path attached to a contact part can be reduced significantly.

[Means of Claim 8]
According to the means described in claim 8, the abutting portion is located at the axial position of the valve body when the valve body and the nozzle body are abutted so as to block the high-pressure fluid from flowing into the nozzle hole. The valve body and the nozzle body are brought into contact with each other only in a region covering the entire circumference including the entire opening where the opening is provided, and a part of the opening cross section of the entire opening cross section of the opening is provided. And is formed such that a region between the first seal portion and the second seal portion other than the contact portion is formed as a storage chamber.

  As a result, the storage chamber and the opening communicate with each other even when the engine is stopped, so that the fluid to be stored is directly filled up to the opening.Therefore, there is a minute lift at the initial stage of injection at startup. In addition, a large amount of the stored fluid can be supplied immediately, and a rapid fluid flow to the nozzle hole becomes possible. Therefore, it becomes easier to obtain good atomization of the spray, and accuracy at the time of injection of a minute amount can be improved.

[Means of Claim 9]
According to the means of the ninth aspect, the abutting portion is located at the axial position of the valve body when the valve body and the nozzle body are abutted so as to block the high pressure fluid from flowing into the nozzle hole. The valve body and the nozzle body are brought into a non-contact state in a region covering the entire circumference including the entire opening where the opening is provided, and the valve body is formed so as not to block the entire opening cross section of the opening. It is characterized by that.

  Thereby, since the valve body does not block the entire opening cross section of the opening, the storage chamber and the opening are communicated even when stopped, and the stored fluid is directly filled up to the opening. In the initial stage of injection at start-up, a large amount of stored fluid can be supplied immediately even with a minute lift, and a rapid fluid flow to the nozzle hole is possible. Therefore, it becomes easier to obtain good atomization of the spray, and accuracy at the time of injection of a minute amount can be improved.

[Means of Claim 10]
According to the means of claim 10, the valve body is accommodated in the first valve body that opens and closes the first nozzle hole that is opened first in the nozzle hole, and the first valve body. And a second valve body that opens and closes a second nozzle hole that is opened after the first nozzle hole, the first valve body has a contact portion, and the first valve body A storage chamber is formed when contacting the nozzle body.

  Thereby, there exists an effect | action and effect similar to the means of Claim 1.

  The best mode of the present invention will be described together with Example 1 shown in the drawings. In the first embodiment, the fluid injection nozzle is applied to the automobile field and is a fuel injection nozzle suitable for application to a fuel injection device of an internal combustion engine that uses fuel as a fluid.

[Configuration of Example 1]
The configuration of the fuel injection nozzle of this embodiment will be described with reference to FIG. FIG. 1A is a schematic cross-sectional view schematically showing a configuration of a fuel injection nozzle, a fuel injection valve, and a fuel injection device, and FIG. 1B is an enlarged cross-sectional view of a main part of the fuel injection nozzle. .
A fuel injection nozzle 1 (hereinafter referred to as nozzle 1) is mounted on each cylinder of an internal combustion engine (hereinafter referred to as engine), for example, a direct injection engine (not shown) such as a multi-cylinder diesel engine, and burns. The fuel is injected into the chamber. Further, in order to cope with atomization of the spray in the low rotation region of the engine and short-term large-quantity injection in the high rotation region, the variable injection hole type can change the number of injection holes to be opened according to the injection amount.

  The nozzle 1 constitutes a fuel injection valve 3 together with an electromagnetic valve 2 that repeatedly activates and deactivates in response to a command from an electronic control unit (ECU) (not shown). The fuel injected from the fuel injection valve 3 is high-pressure fuel discharged at a high pressure by a known injection pump (not shown), and is supplied to the nozzle 1 via a known common rail 4. That is, the fuel injection valve 3 constitutes a fuel injection device that injects and supplies fuel to the engine together with the injection pump, the common rail 4 and the like, and the nozzle 1 supplies high-pressure fuel using the injection pump and the common rail 4 as a predetermined supply source. Receive.

  As shown in FIG. 1A, the nozzle 1 includes a nozzle body 9 having first and second injection holes 7 and 8 that are opened in two stages, and first and second injection holes 7 and 8. The first valve body 10 that opens and closes the first nozzle hole 7 that opens first, the second nozzle hole 8 that opens after the first nozzle hole 7 opens and closes, and is coaxial with the first valve body 10. And the second valve body 11 moving to the position. The other ends of the first and second valve bodies 10 and 11 abut (seat) the valve seat 22 provided at the other end of the nozzle body 9 so that fuel flows into the first and second injection holes 7 and 8. In addition, the fuel is allowed to flow into the first and second nozzle holes 7 and 8 by being separated (separated) from the valve seat 22. At this time, a structural portion having a function of blocking the inflow of fuel by contacting the other ends of the first and second valve bodies 10 and 11 to the valve seat 22 is referred to as a seal portion. Moreover, the contact part of the 1st, 2nd valve bodies 10 and 11 which comprise a seal part is called a seat part.

  The nozzle body 9 is a substantially hollow cylindrical body with a bottom, and includes a guide hole 12 that accommodates the first valve body 10 and the second valve body 11 in a reciprocating manner therein, a valve seat 22, and a first jet. A hole 7 and a second nozzle hole 8 are formed. The guide hole 12 extends in the axial direction inside the nozzle body 9 and accommodates the first valve body 10 and the second valve body 11 so as to be movable in the axial direction. The guide hole 12 has one end connected to the back pressure chamber 17 and the other end connected to the valve seat 22.

  As shown in FIG. 1B, the valve seat 22 is formed in a substantially conical shape, and in the order of the first injection hole 7 and the second injection hole 8 toward the downstream side of the fuel flow of the valve seat 22. The first nozzle hole 7 is formed so as to be located outside the valve seat 22. Further, the valve seat 22 is configured with respective seal portions that block or allow fuel to flow in by the second valve body 11 as the inner needle and the first valve body 10 as the outer needle seated or separated. Has been.

  As shown in FIG. 1A, the first valve body 10 is formed in a substantially cylindrical shape, and is loosely fitted in the guide hole 12 through a predetermined gap. A first upper end face 31 that receives the pressure in the back pressure chamber 17 is formed on the side opposite to the injection hole of the first valve body 10, and faces the valve seat 22 on the injection hole side of the first valve body 10, and is substantially A conical first lower end surface 32 is formed.

  As shown in FIG. 1B, the first lower end surface 32 is formed with a contact surface 32 having a substantially conical inclined surface similar to the valve seat 22, and upstream of the substantially conical contact surface 32. On the side and the downstream side, there are formed substantially conical inclined surfaces 33 and 34 having conical angles toward the apex of the substantially conical shape formed at different angles. Edge portions are formed at the transition portions of the conical inclined surfaces 33 and 34, and the edge portions form first seat portions 32 a and 32 b that abut against the valve seat 22.

  The first seat portion 32a, 32b is in contact with the valve seat 22, and the first seal portion S1 is disposed upstream of the first injection hole 7 for blocking fuel from flowing into the first injection hole 7. A seal portion having a two-point seal structure of the second seal portion S2 is formed on the downstream side of the first injection hole 7. At this time, the first valve body 10 is seated or separated so as to block or allow the fuel to flow into the first nozzle hole 7. The high pressure fuel can also flow in from the fuel passage 18 in a predetermined gap formed between the first valve body 10 and the second valve body 11 on the downstream side of the hole 7, and this high pressure fuel flows in. In order to prevent this, a two-point seal structure in which a seal portion is formed on the upstream and downstream sides with respect to the first injection hole 7 is required. A gap (first gap) 16 is formed between the first lower end surface 32 and the valve seat 22 so as to expand and contract by seating or separation, and the first gap 16 constitutes a fuel path through which fuel flows.

  As described above, the inclination of the substantially conical inclined surface is slightly changed to form the first sheet portions 32a and 32b at the transition portions of the substantially conical inclined surfaces 33 and 34, and this first sheet portion 32a, By contacting 32b with the valve seat 22 having a substantially conical inclined surface, a seal portion of a two-point seal structure that blocks or allows the inflow of fuel is configured. Although this is not different from the conventional one, in particular, in the present embodiment, in order to suppress the acceleration of the sheet wear of the first sheet portions 32a and 32b, it is possible to reduce the seal surface pressure by contacting the surface. The contact portion A is characterized in that the contact portion A is disposed between the first sheet portions 32a and 32b via the concave groove portion U.

  Hereinafter, this configuration will be described in detail with reference to FIG. FIG. 2A is an enlarged configuration diagram of the valve portion of the nozzle 1, schematically showing the right half seated in a sectional view and the left half in a sectional view without being sectioned. FIG. 2B is a plan view of the valve portion of the nozzle 1 as viewed from the other side.

  As shown in FIG. 2A, the first seat portions 32a and 32b are substantially conical inclined surfaces with the seat portions 32a and 32b as base points, that is, the apex angle formed by the conical surfaces is the top formed by the valve seat 22. In theory, a circular line seal portion is formed by forming it slightly different from the corner. Two circular groove portions U having a predetermined width and depth in a direction facing each other with each circular line seal portion as a base point (hereinafter, the outer concave groove portion U is a first concave groove portion U1, and the inner side is a second concave groove portion. U2) is provided. In addition, a contact portion A that contacts the valve seat 22 in a planar shape is formed between the first and second groove portions U1 and U2, and only the groove width of the first and second groove portions U1 and U2 is provided. It has a reduced effective width H.

  The abutting portion A that abuts in a planar manner matches the virtual conical surface B formed by the two-point seal structure (hereinafter referred to as the outer two-point seal structure) of the first sheet portions 32a and 32b. Accordingly, the two-point seal structure of the second sheet portions 35a and 35b (hereinafter referred to as the inner two-point seal structure) between the first sheet portions 32a and 32b, and the second sheet portion 35a of the inner two-point seal structure. , 35b, a face seal portion 38 is formed. First and second seal portions S1 and S2 that block or allow fuel to flow into the first injection hole 7 by the first seat portions 32a and 32b contacting or separating from the valve seat 22; When the seat portions 35a and 35b contact or separate from the valve seat 22, the third seal portion S3 and the fourth seal portion S4 that block or allow the fuel to flow into the first injection hole 7 are formed. . Further, the face seal portion 38 of the contact portion A contacts or separates from the opening peripheral portion which is the outer peripheral edge of the opening portion of the first injection hole 7 of the valve seat 22, so that the fuel is more reliably supplied to the first injection hole 7. It will be blocked or allowed to enter.

  However, in the actual processing of the first and second concave groove portions U1 and U2, it is extremely difficult to perform the concave groove processing with the first sheet portions 32a and 32b being the line seal portions. Therefore, it is allowed to shift the groove base point until the first sheet portions 32a and 32b are equal to or smaller than the allowable surface width (for example, 50 μm at maximum), and a feasible processing method is adopted. Preferably, assuming that the first seat portions 32a and 32b are slightly elastically deformed or conformally deformed microscopically, the first valve body 10 and the valve seat 22 at the contact portion A when initially contacted Is provided so as to be separated with a slight gap (for example, about several μm), and the first valve body 10 and the valve seat 22 are further brought closer to the stable position than in the initial contact state. In this case, the contact portion A is slightly lower than the virtual conical surface B in advance so that the surface width of the first seat portions 32a and 32b is less than the allowable surface width (for example, a maximum of 50 μm) and contacts the valve seat 22 ( It may be configured to cut deeply. In any case, the first valve body 10 is seated on the valve seat 22, the contact portion A reduces the sealing surface pressure by the face seal portion 38, and the first seat portions 32a and 32b are microscopically elastic. It does not increase the surface pressure more than the predetermined surface pressure value due to deformation, familiar deformation, or slight contact (initial) wear, but the minimum required surface pressure value (allowable surface pressure value and Any structure may be used as long as it is easy to ensure a high sealing performance while suppressing seat wear.

  Further, the first and second concave groove portions U1 and U2 attached to the first valve body 10 and provided substantially symmetrically on the upstream and downstream sides of the fuel flow with the first injection hole 7 interposed therebetween are the first seat portion 32a, When the valve 32b and the second seat portions 35a and 35b come into contact with the valve seat 22, the storage chamber Q that stores fuel (hereinafter referred to as the first storage chamber Q1 and the second storage chamber Q formed in the first concave groove portion U1). The storage chamber Q formed in the concave groove portion U2 is called a second storage chamber Q2. The storage chamber Q facilitates the supply of fuel that promotes good spraying at the initial stage of fuel injection. Therefore, in order to improve the fuel spray characteristic at the time of the micro lift at the initial stage of fuel injection, the first and second storage chambers Q1, Q2 for storing the fuel are within the range below the allowable surface pressure value of the contact portion A. It is desirable to be formed close to the opening peripheral edge of one nozzle hole 7, and the point is to set the effective width H of the face seal portion 38 formed in the contact portion A as small as possible. As a result, the flow resistance of the fuel flowing through the minute gap during the minute lift is reduced, and the stored fuel is made to flow in a large amount and immediately into the first injection hole 7 for good atomization of the spray. Can be obtained.

  As described above, in the present embodiment, the two first and second concave groove portions U1 and U2 are provided approximately symmetrically across the first injection hole 7 inside the outer two-point seal structure, and the inner two-point seal structure is further provided. Constitute. Then, a contact portion A is provided between the inner two-point seal structure to form a surface seal portion 38, the seal surface pressure is lowered, and the seal surface pressure of each seal portion of each two-point seal structure is reduced to a predetermined surface. By suppressing the pressure value, acceleration of seat wear is suppressed. Further, by providing the first and second storage chambers Q1 and Q2 in which fuel is stored when the abutting portion A is seated, fuel supply at the time of minute lift is facilitated, and fuel spray characteristics are improved. It is characterized by.

  The relative position between the abutting portion A and the first sheet portions 32a and 32b and the effective width H of the abutting portion A are mainly the surface pressure to be reduced, that is, the allowable surface pressure value that can suppress the promotion of sheet wear. Is determined by the size of Therefore, there is a case where the effective width H has to be increased, but the abutting portion A only needs to be between the first sheet portions 32a and 32b. Therefore, the concave groove portion U is connected to the first sheet portions 32a and 32b. It is sufficient if it is provided on at least one side between the first nozzle holes 7. Further, when the effective width H is small, the concave groove portion U can be provided on both sides, and preferably the upstream and downstream sides of the first injection hole 7 so as not to cause uneven injection pressure at the initial stage of injection. The center of the contact portion A is located at a position that divides the distance between the first and second storage chambers Q1 and Q2 by 2 and the first and second storage chambers Q1 and Q2 are also in the first nozzle hole 7. It is preferable to set the storage volumes of the first and second storage chambers Q1 and Q2 to be substantially the same volume, being positioned substantially symmetrically on the upstream and downstream sides with respect to the central axis.

  The first and second storage chambers Q1 and Q2 are constituted by first and second concave groove portions U1 and U2 having a concave groove shape, but the first and second concave groove portions U1 and U2 are grooves. The cross-sectional shape is not limited to a concave shape, and may be an arc shape, a triangular shape, a square shape, or a polygonal shape having more than that. Preferably, a cross-sectional shape that forms an angle of attack where the fuel smoothly flows into the first and second storage chambers Q1 and Q2 at the time of the minute lift is suitable.

  In this embodiment, as shown in FIG. 2, when the first valve body 10 is brought into contact with the valve seat 22 so as to block the high-pressure fuel from flowing into the first injection hole 7, the contact portion The apex direction (axis) formed by the conical inclined surface on the conical inclined surface of the contact portion A so that the high-pressure fuel flows between the storage chamber Q and the opening of the first injection hole 7 through A. A communication path R in which a plurality of slit-shaped U-shaped grooves along the direction) is radially arranged is configured.

  The slit-shaped U-shaped groove preferably has a depth similar to the depth of the first and second concave groove portions U1 and U2 forming the first and second storage chambers Q1 and Q2, and is deeper than this. Even if it has length, if it is the length which does not exceed the 1st sheet parts 32a and 32b used as the starting point of formation of the 1st and 2nd ditch parts U1 and U2, it will not restrict to this. Further, the width of the slit-shaped U-shaped groove may be larger than the opening diameter of the first nozzle hole 7, and the arrangement pitch (interval) of the plurality of U-shaped grooves may be smaller than the first nozzle hole 7. As long as it is smaller than the diameter of the opening, and a plurality of sets of the contact portions A and the communication passages R are arranged adjacent to each other, a plurality of sets of openings of the plurality of first injection holes 7 are arranged in the circumferential direction. It is configured to always communicate with any one of the communication paths R (see FIG. 2B).

  As a result, the communication path R increases the flow area through which fuel flows between the first and second storage chambers Q1 and Q2 and the opening of the first injection hole 7, so that the first and second storage chambers Q1 and Q2 It is possible to flow the fuel stored in a large amount and immediately into the first nozzle hole 7 to further improve the spray characteristics at the time of micro lift. Therefore, the slit-shaped U-shaped groove constituting the communication path R is not limited to being provided on the first valve body 10 side, and may be provided on the valve seat 22 side. Further, the cross-sectional shape is not limited to a U-shape, and may be a triangular shape, a square shape, or a polygonal shape having more than that.

  The slit-shaped U-shaped groove provided on the conical inclined surface of the contact portion A is a vertical groove radially disposed along the apex direction, that is, the axial direction (vertical direction in the drawing) formed by the conical inclined surface. However, the present invention is not limited to this, and oblique grooves (see, for example, FIG. 3 (a)) that are radially inclined with respect to the axial direction, or a lattice-like structure in which the oblique grooves are inclined in opposite directions to intersect with each other It may be a slant groove. Moreover, it may replace with inclination and the spiral groove (for example, refer FIG.3 (b)) which arranges a U-shaped groove | channel helically on a cone inclined surface may be sufficient. Thereby, compared with the longitudinal groove processing of an axial direction, reduction of a process man-hour can be anticipated.

  Further, as shown in FIG. 3C, at least one U-shaped lateral groove T continuous in the circumferential direction connecting the center position of the first injection hole 7 is formed at the approximate center in the axial direction of the longitudinal groove of this embodiment. The provided lateral groove structure may be used. According to this structure, the fuel supply for injection to the plurality of first injection holes 7 is supplied not only by the vertical grooves but also by the horizontal grooves T, so that the fuel spray at the time of the minute lift becomes better. Furthermore, by providing at least one horizontal groove T, restrictions such as the groove width and arrangement pitch of the vertical grooves are eliminated. For example, a groove arrangement of at least one vertical groove and at least one horizontal groove T is provided. As a result, fuel for injection to the plurality of first injection holes 7 can be supplied. Preferably, the number of longitudinal grooves is equal to or less than that of the first nozzle holes 7, and one transverse groove T is preferably provided substantially in the center. By adopting this configuration, the number of processing steps of the communication path R can be greatly reduced. I can expect.

  Further, as shown in FIG. 1, a sleeve 19 forming the back pressure chamber 17 is disposed between the first upper end surface 31 and the back pressure chamber 17, and the sleeve 19 and the first valve body 10 side are disposed. Between the fixed seat 20, the 1st spring 5 as an urging | biasing means is arrange | positioned. The first spring 5 is configured to bias the first valve body 10 in the seating direction (valve closing direction) in which the first spring 5 is seated on the valve seat 22. By adjusting the pressure in the back pressure chamber 17, the first valve body 10 is reciprocated in the axial direction. A fuel passage 23 is formed between the outer periphery of the first valve body 10 and the inner periphery of the guide hole 12 of the nozzle body 9 facing the outer periphery. The fuel passage 23 constitutes a fuel path that guides the high-pressure fuel supplied through the fuel reservoir chamber 14 to the first injection hole 7.

  The 2nd valve body 11 is formed in the substantially cylindrical shape, and is accommodated in the inside of the 1st valve body 10 so that reciprocation is possible. Specifically, it is accommodated in the guide hole 13 of the first valve body 10 so as to be able to reciprocate. A second lower end surface 42 is formed on the nozzle hole side of the second valve body 11 so as to face the valve seat 22. The second lower end surface 42 is formed so as to be slightly inclined with respect to the valve seat 22, that is, so that the apex angle formed by the conical inclined surface is slightly increased.

  Accordingly, the third seat portion 42 a is formed on the outer peripheral side of the second valve body 11, and the third seat portion 42 a is seated on or separated from the valve seat 22, so that the fuel flows into the second injection hole 8. Block or allow. At this time, the upstream side of the second injection hole 8 forms a fifth seal portion S5 that blocks fuel from flowing into the second injection hole 8 when the third seat portion 42a is seated. The fifth seal portion S5 is formed on the outer peripheral side of the second injection hole 8 of the valve seat 22, that is, on the upstream side of the fuel flow, and when the second valve body 11 is seated on the valve seat 22, the fifth seal portion S5 is separated from the upstream side. The inflow of fuel into the second injection hole 8 of high pressure fuel can be blocked. A gap (second gap) 27 is formed between the second lower end surface 42 and the valve seat 22 so as to expand and contract by seating and separation, and the second gap 27 constitutes a fuel path through which fuel flows.

  Further, a second upper end surface 41 that receives the pressure in the back pressure chamber 17 is formed on the side opposite to the injection hole of the second valve body 11, and the second upper end surface 41 is separated from the second upper end surface 41 by a predetermined distance. A flange 43 having a larger area than the upper end surface 41 is provided. Between the flange 43 and the back pressure chamber 17, the second spring 6 as an urging means urges the second valve body 11 in the seating direction (valve closing direction) in which the valve seat 22 is seated. Has been placed. By adjusting the pressure in the back pressure chamber 17, the second valve body 11 can be reciprocated in the axial direction. A fuel passage 18 is formed between the inner periphery of the guide hole 13 of the first valve body 10 and the outer periphery of the second valve body 11. The fuel passage 18 constitutes a fuel path that guides the relatively high pressure fuel in the back pressure chamber 17 to the first and second injection holes 7 and 8.

  The valve body 30 includes a back pressure chamber 17, and a fuel supply passage 24 and a return passage 25 are connected to the back pressure chamber 17. The fuel supply passage 24 is provided with an inlet throttle 28, and the return passage 25 is provided with an outlet throttle 29. The fuel supply passage 24 is branched from the high pressure fuel passage 15 in order to supply high pressure fuel to the back pressure chamber 17 and the fuel reservoir chamber 14. The return passage 25 is connected to a return fuel path for returning surplus fuel in the back pressure chamber 17 to the fuel tank 26. Then, the nozzle body 9 is screwed and fastened to the valve body 30 by the retaining nut 40 to constitute the fuel injection valve 3.

  An electromagnetic two-way valve 21 that switches communication between the return passage 25 and the low-pressure passage on the fuel tank 26 side and shut-off is provided on the downstream side of the return fuel path. By adjusting the area ratio of the channel cross-sectional area of the inlet throttle 28 and the outlet throttle 29 with the electromagnetic valve 2, the balance between the inflow amount and the outflow amount of the high-pressure fuel in the back pressure chamber 17 can be adjusted. Accordingly, the fuel pressure increase / decrease rate in the back pressure chamber 17 can be adjusted. The back pressure chamber 17 is a common pressure control chamber that applies pressure in the seating direction (valve closing direction) to the first valve body 10 and the second valve body 11.

[Operation of Example 1]
The operation of the nozzle 1 having the above configuration will be described with reference to FIGS. 1 and 4. Here, FIG. 4 is a partially enlarged cross-sectional view showing the operation of the valve portion and the seal portion of the fuel injection nozzle, where (a) shows when the injection is stopped, and (b) shows when the valve is open with only the first injection hole. , (C) shows the time when the second nozzle hole is opened. In FIGS. 4A to 4C, substantially the same components as those in FIG.

(When injection stops)
As shown in FIGS. 1 and 4A, the high-pressure fuel accumulated in the common rail 4 is supplied to the back pressure chamber 17 and the fuel reservoir chamber 14 through the high-pressure fuel passage 15 and the fuel supply passage 24. . At this time, since the solenoid valve 2 is not energized, the solenoid two-way valve 21 is closed. Accordingly, the first and second valve bodies 10 and 11 are seated on the valve seat 22 by the urging force of the high-pressure fuel and the urging forces of the first spring 5 and the second spring 6, and the first seat of the first valve body 10. The portions 32a and 32b generate a seal surface pressure with the valve seat 22, and the high pressure fuel flows into the first injection hole 7 exclusively by the outer two-point seal structure including the first and second seal portions S1 and S2. Further, the seal surface pressure is lowered to a predetermined surface pressure value by the surface seal portion 38 of the contact portion A, and the first injection hole 7 is closed by the contact portion A. It is not injected from the injection hole 7. Similarly, the third seat portion 42a of the second valve body 11 generates a predetermined surface pressure with the valve seat 22 to block fuel from flowing into the second injection hole 8 formed by the fifth seal portion S5. Therefore, the fuel is not injected from the second injection hole 8 downstream of the fuel flow.

(When opening only the first nozzle hole)
As shown in FIG. 1 and FIG. 4B, when the electromagnetic valve 2 is energized in response to a command from the ECU and the electromagnetic two-way valve 21 is opened, the back pressure fuel is supplied from the back pressure chamber 17 through the return passage 25. Is discharged and the back pressure decreases. The reduction in the back pressure is reduced at a predetermined lowering speed according to the area ratio between the inlet throttle 28 and the outlet throttle 29. When the fuel pressure in the back pressure chamber 17 decreases to the valve opening pressure of the first valve body 10, the first valve body 10 is lifted, the first seat portions 32a, 32b are separated from the valve seat 22, and the first valve The body 10 is opened. For this reason, the injection is started from the first injection hole 7 and the injection amount (referred to as the first injection rate) from the first injection hole 7 increases with the lift of the first valve body 10.

  At this time, immediately after the opening of the first nozzle hole 7, the first gap between the valve body 10 and the valve seat 22 of the first seal portion S 1 is larger than the effective cross-sectional area (first nozzle hole effective area) of the first nozzle hole 7. Since the effective area of 16 (first gap effective area) is smaller, the first injection rate is governed by the first gap effective area. Therefore, in the micro lift at the initial stage of injection, the effective area of the first gap is very small, and the fuel flowing through the small first gap 16 is extremely small, but the first and second storage chambers Q1 and Q2 are provided. As a result, a large amount of fuel is supplied immediately and a predetermined first injection rate can be obtained while being a minute lift, and good spray characteristics can be exhibited. Thereafter, since the effective area of the first gap increases with the lift of the first valve body 10, the first injection rate continues to increase.

  When the first clearance effective area becomes larger than the first injection hole effective area of the first injection hole 7, the first injection rate is controlled by the first injection hole effective area, and the first injection hole effective area is Since it is constant regardless of the lift of the first valve body 10, the first injection rate is constant without increasing.

(When opening the second nozzle hole)
As shown in FIGS. 1 and 4C, when the fuel pressure in the back pressure chamber 17 further decreases to the valve opening pressure of the second valve body 11, the second valve body 11 starts to lift. Then, the third seat portion 42a is separated from the valve seat 22, and the second valve body 11 is opened. When the second valve body 11 is opened, the fuel in the back pressure chamber 17 and the fuel passage 18 flows into the second injection hole 8, and the fuel is injected from the second injection hole 8. At this time, immediately after the opening of the second nozzle hole 8, the second valve body 11 and the valve seat 22 of the fifth seal portion S 5 are larger than the effective cross-sectional area (second nozzle hole effective area) of the second nozzle hole 8. Since the effective area of the two gaps 27 (second gap effective area) is smaller, the injection amount (referred to as the second injection rate) from the second nozzle holes 8 is governed by this second gap effective area. Since the effective area of the second gap increases with the lift of the second valve body 11, the second injection rate continues to increase.

  When the second gap effective area becomes larger than the second nozzle hole effective area of the second nozzle hole 8, the second injection rate is governed by the second nozzle hole effective area, and the second nozzle hole effective area is the second nozzle hole effective area. Since the two-valve body 11 is constant regardless of the lift, the second injection rate is constant without increasing. The increase and constant characteristics of the second injection rate are not different from those of the first injection ratio, but the increase and constant characteristics of the second injection rate correspond to short-term large-volume injection in the high engine speed range. As a result, the sum of the first and second injection rate characteristics is injected into each cylinder of the engine.

(At the end of injection)
As shown in FIG. 1, when the electromagnetic two-way valve 21 stops operating and closes in response to a command from the ECU, the discharge of back pressure fuel through the return passage 25 stops, and the high pressure fuel flows through the fuel supply passage 24. The pressure chamber 17 is supplied as back pressure fuel, and the back pressure increases. As a result, first, in the first valve body 10, the urging force acting in the valve closing direction becomes larger than the urging force acting in the valve opening direction, and the first valve body 10 starts to descend. Next, in the second valve body 11, the urging force acting in the valve closing direction becomes larger than the urging force acting in the valve opening direction, and the second valve body 11 starts to descend.

  At this time, if the first gap effective area becomes smaller than the first nozzle hole effective area, the first injection rate is controlled by the first gap effective area, and the first injection rate starts to decrease. Since the first gap effective area decreases as the first valve body 10 descends, the first injection rate continues to decrease. Then, the first valve body 10 is seated on the valve seat 22 and the first injection hole 7 is closed. As a result, the first injection rate becomes zero.

  When the second gap effective area is smaller than the second nozzle hole effective area, the second injection rate is controlled by the second gap effective area, and the second injection rate starts to decrease. And since the 2nd clearance effective area reduces with the fall of the 2nd valve body 11, the 2nd injection rate continues decreasing. Then, the second valve body 11 is seated on the valve seat 22 and the second injection hole 8 is closed. As a result, the second injection rate becomes 0, and the overall injection rate also becomes 0.

[Effect of Example 1]
The fuel injection nozzle 1 of the present invention includes a nozzle body 9 having a first injection hole 7 and a valve seat 22, a first valve body 10 movably accommodated in the nozzle body 9, a first valve body 10 and a valve A seal portion that blocks high-pressure fuel from flowing into the first nozzle hole 7 by contact with the seat 22, and is provided on the upstream side of the opening of the first nozzle hole 7; A seal portion having a two-point seal structure having a second seal portion S2 provided on the downstream side is provided, and high-pressure fuel flows into the first injection hole 7 between the first seal portion S1 and the second seal portion S2. When the first valve body 10 and the valve seat 22 are brought into contact with each other so as to cut off the contact, the contact portion A where the first valve body 10 and the valve seat 22 abut in a planar shape, and the first seal portion S1 Between the first seal hole and the opening of the first injection hole 7 or at least one of the second seal part S2 and the opening of the first injection hole 7. A valve body 10 and the valve seat 22 when brought into contact to form a reservoir chamber Q for storing fuel therein.

  By providing the contact portion A where the first valve body 10 and the valve seat 22 are in contact with each other in a planar shape, the seal surface pressure can be reduced, and the first seal portion S1 and the second seal portion S2 are brought to a predetermined seal surface pressure. By suppressing it, it is possible to ensure sufficient sealing performance and to suppress the acceleration of seat wear. Furthermore, the provision of the storage chamber Q facilitates the fuel supply to the first injection hole 7, so that it is possible to obtain good atomization at the time of micro lift at the initial stage of valve opening, and to improve the accuracy at the time of micro quantity injection. It becomes possible.

  Further, a first storage chamber (upstream storage chamber) Q1 and a downstream second seal portion S2 between the first seal portion S1 on the upstream side of the first injection hole 7 and the opening portion of the first injection hole 7. Since two second storage chambers (downstream storage chambers) Q2 are provided between the opening of the first nozzle hole 7 and the storage volumes of the respective storage chambers Q1 and Q2 are set to substantially the same volume, The high-pressure fuel that flows in through the minute gap between the first seal part S1 and the second seal part S2 during the minute lift becomes easier to supply the stored fuel in the respective storage chambers Q1, Q2, and moreover, Since the stored fuel can be supplied evenly and the occurrence of uneven injection pressure at the initial stage of injection can be suppressed, good atomization of the spray can be easily obtained, and the accuracy at the time of injection of a small amount can be improved.

  Further, when the first valve body 10 and the valve seat 22 are brought into contact with each other so as to block the high pressure fuel from flowing into the first injection hole 7, the storage chamber Q and the first injection hole are passed through the contact portion A. The communication passage R is provided so that the high-pressure fuel flows between the openings 7 and the contact portions A and the communication passage R are arranged in a plurality of pairs adjacent to each other. Accordingly, since the communication area between the storage chamber Q and the opening of the first injection hole 7 is enlarged and evenly arranged in the circumferential direction, the first seal portion S1 and the second seal portion S2 at the time of minute lift are provided. The high-pressure fuel flowing in through the minute gap can flow into the first injection hole 7 in a larger amount instantly and without variation. Therefore, it becomes easier to obtain good atomization of the spray, and accuracy at the time of injection of a minute amount can be improved.

[Configuration of Example 2]
A second embodiment of the present invention is shown in FIG. FIG. 5 is an enlarged cross-sectional view and a plan view showing the main part of the nozzle 1. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the nozzle 1 of the first embodiment, the high pressure fuel is blocked from flowing into the first injection hole 7 by the contact between the first valve body 10 and the valve seat 22 upstream of the opening of the first injection hole 7. A first valve seated between the first seal part S1 and the second seal part S2 is provided with a seal part of a two-point seal structure having a first seal part S1 to be performed and a second seal part S2 on the downstream side. The body 10 and the valve seat 22 abut on each other in a planar shape, a contact portion A that contacts the entire opening cross section of the opening portion of the first injection hole 7, an opening portion of the first injection hole 7, and the first seal portion S1. Or at least one between the second seal portion S2 and a storage chamber Q for storing fuel when the first valve body 10 and the valve seat 22 are brought into contact with each other. A communication path R through which high-pressure fuel flows is provided between Q and the opening of the first injection hole 7.

  In the present embodiment, the abutment portion A that abuts in a planar shape is different from the embodiment 1 in which the abutment portion A abuts on the entire opening cross section of the opening portion of the first injection hole 7, and a part of the opening portion of the first injection hole 7. It is comprised so that it may contact | abut only to the opening cross section. Then, the effective width H of the contact portion A is set so that the surface seal portion 38 of the contact portion A has a predetermined surface pressure value or less, and at least the region other than the region where the contact portion A is provided is the storage chamber Q. Set as Therefore, at least one of the two storage chambers Q formed between the first seal portion S1 and the second seal portion S2 is wrapped and stopped upstream or downstream of the opening of the first nozzle hole 7. Even at times, the storage chamber Q and the opening of the first nozzle hole 7 communicate with each other.

  As shown in FIG. 5, the first seat portions 32a and 32b are arranged so as to be in contact with or separated from the valve seat 22, and form a first seal portion S1 and a second seal portion S2 that block or allow the inflow of fuel. is doing. The first seat portions 32 a and 32 b are theoretically formed by forming conical inclined surfaces with the seat portions 32 a and 32 b as the base points, that is, the apex angle formed by the conical surfaces is slightly different from the apex angle formed by the valve seat 22. Specifically, it forms a circular line seal portion. The two first groove portions U1 and the second groove portion U2 having a predetermined width and depth in a direction facing each other with the circular line seal portion as a base point, to the vicinity of the opening center portion of the first injection hole 7, It extends at least across the peripheral edge of the opening. By the first and second concave groove portions U1 and U2, the contact portion A forms a face seal portion 38 having an effective width H reduced by an enlarged groove width of the two concave groove portions U1 and U2. That is, the abutting portion A does not abut against the entire opening cross section of the opening of the first nozzle hole 7, but the opening center part is connected in the circumferential direction, and a part of the opening is opened by the annular surface seal portion 38. Abutting on the cross section, the periphery of the opening is always configured to communicate with either or both of the first groove portion U1 and the second groove portion U2.

  Thereby, between the two-point seal structure of the first sheet portions 32a and 32b (hereinafter referred to as the outer two-point seal structure), the two-point seal structure of the second sheet portions 35a and 35b (hereinafter referred to as the inner two-point seal structure). The surface seal portion 38 is formed between the second sheet portions 35a and 35b of the inner two-point seal structure. The first seat portions 32a and 32b are brought into contact with or separated from the valve seat 22, thereby forming the first and second seal portions S1 and S2, and blocking the flow of fuel into the first injection hole 7. Alternatively, at the same time as allowing, the second seat portions 35a, 35b contact or separate from the valve seat 22 to form the third and fourth seal portions S3, S4, and the fuel flows into the first injection hole 7. Block or allow. Further, the surface seal portion 38 of the contact portion A contacts or separates from the opening center portion of the first injection hole 7 of the valve seat 22 to reduce the seal surface pressure, and the fuel flows into the first injection hole 7. It is the structure which interrupts | blocks or accepts.

  At this time, the face seal portion 38 of the contact portion A has only an effective width H that contacts only a part of the opening cross section of the opening portion of the first injection hole 7, so that the third two-point seal structure is the third. Along with the seal part S3 and the fourth seal part S4, the opening part of the first injection hole 7 is not directly cut off. Blocking or allowing fuel to flow into the first injection hole 7 is exclusively performed by the first seal portion S1 and the second seal portion S2 of the outer two-point seal structure. However, since the surface seal portion 38 of the contact portion A has a predetermined effective width H, the seal surface pressure can be reduced, and the flow of fuel into the first injection hole 7 is blocked or allowed. By suppressing the seal portion of the outer two-point seal structure to a predetermined seal surface pressure, it is possible to ensure sufficient sealing performance and to suppress the promotion of seat wear.

  Further, the communication path R may be configured by radially attaching a plurality of slit-shaped U-shaped grooves along the apex direction formed by the conical inclined surface to the conical inclined surface of the contact portion A. The arrangement of the communication path R is a case where the effective width H of the contact portion A becomes larger depending on the setting of the allowable surface pressure value that suppresses the acceleration of seat wear, and the first and second concave groove portions U1 and U2 are arranged. This is particularly effective when the groove width is slightly in communication with a part of the opening of the first injection hole 7. Therefore, since the communication area between the first and second storage chambers Q1 and Q2 and the opening of the first injection hole 7 is enlarged, a large amount of fuel is stored in the first and second storage chambers Q1 and Q2, and It is possible to immediately flow into the first nozzle hole 7 and further improve the spray characteristics at the time of micro lift. Therefore, in addition to the communication through the lap between the first and second concave groove portions U1 and U2 and the opening of the first nozzle hole 7, the flow through the communication path R can be secured, so the spray characteristics from the time of the minute lift are further improved. It becomes easy to do.

  This is the only difference between the first embodiment and the first embodiment, the other configurations are not changed, and the conditions such as the depth and width of the U-shaped groove related to the arrangement of the communication path R are also changed. Absent. Accordingly, the same operations and effects as those of the first embodiment are obtained. That is, the surface seal portion 38 of the contact portion A reduces the seal surface pressure and suppresses the acceleration of seat wear by suppressing the seal surface pressure of each seal portion of the two-point seal structure to a predetermined surface pressure value. Further, when the contact portion A is seated, a part of the opening of the first injection hole 7 and at least one of the first and second storage chambers Q1 and Q2 communicate with each other. Since communication between the storage chambers Q1 and Q2 and the opening can be ensured by the communication path R, a large amount of fuel stored in the first and second storage chambers Q1 and Q2 can be immediately supplied to the first nozzle hole 7. This makes it possible to improve the spray characteristics at the time of minute lift. Moreover, compared with Example 1, the structure of a valve body can be simplified and reduction of a process man-hour is attained.

[Configuration of Example 3]
A third embodiment of the present invention is shown in FIG. FIG. 6 is an enlarged cross-sectional view and a plan view showing the main part of the nozzle 1 in the third embodiment. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, unlike the nozzle 1 of the first embodiment, the contact portion A having the face seal portion 38 does not contact the entire opening cross section of the opening portion of the first injection hole 7, and the second embodiment Thus, it does not contact only a part of the opening cross section. When the contact portion A and the valve seat 22 are brought into contact with each other, the face seal portion 38 facing the opening portion of the first injection hole 7 forms a non-contact state with the entire opening cross section of the opening portion. It is the structure which contact | abuts the opening peripheral part of the upstream and downstream of an opening part on both sides of a part.

  That is, in detail, as shown in FIG. 6, the third storage chamber Q3 is formed by the third concave groove U3, like the first and second storage chambers Q1 and Q2. The contact portion A is divided into two substantially at the center by the third concave groove portion U3, and the first contact portion A1 on the upstream side and the second contact on the downstream side across the first injection hole 7. The face seal portion 38 that constitutes the contact portion A2 and has the effective widths H1 and H2 of the contact portions A1 and A2 so that the first and second contact portions A1 and A2 have a predetermined surface pressure value or less. Preferably, the third storage chamber Q3 communicates with the first and second storage chambers Q1 and Q2 in the first contact portion A1 on the upstream side or the second contact portion A2 on the downstream side. R is provided.

  The first seat portions 32a and 32b are disposed so as to be able to contact and separate from the valve seat 22, and form a first seal portion S1 and a second seal portion S2 that block and allow the inflow of fuel. The first seat portions 32 a and 32 b are theoretically formed by forming conical inclined surfaces with the seat portions 32 a and 32 b as the base points, that is, the apex angle formed by the conical surfaces is slightly different from the apex angle formed by the valve seat 22. Specifically, it forms a circular line seal portion. Two first groove portions U1 and second groove portions U2 having a predetermined width and depth are provided up to the opening peripheral edge portion of the first injection hole 7 in a direction facing each other with the circular line seal portion as a base point. ing. Although the contact portion A is reduced by the groove widths of the two recessed groove portions U1 and U2 by the first and second recessed groove portions U1 and U2, the wide contact portion A that contacts the opening peripheral edge of the first injection hole 7 is used. (So far, this is the same mode as in Example 1).

  In the present embodiment, the face seal portions 38 that contact the peripheral edge of the opening are further provided on the upstream side and the downstream side at positions substantially opposite the opening portion of the first injection hole 7 at the substantially central portion of the contact portion A. A third groove U3 is formed to form the first contact portion A1 and the second contact portion A2. That is, the opening of the first injection hole 7 is not contacted by the contact part A, but the opening peripheral part is the first contact part A1 on the upstream side and the second contact part is on the downstream side. The opening of the first nozzle hole 7 is contacted at A2, and is formed between the first contact part A1 and the second contact part A2 upstream and downstream of the opening part across the opening part. It is comprised so that it may block | close in the state connected with the 3rd storage chamber Q3.

  Thereby, between the two-point seal structure of the first sheet portions 32a and 32b (hereinafter referred to as the outer two-point seal structure), the two-point seal structure of the second sheet portions 35a and 35b (hereinafter referred to as the inner two-point seal structure). And a two-point seal structure (hereinafter referred to as the innermost two-point seal structure) of the fourth sheet portions 36a and 36b is formed between the inner two-point seal structure. Further, between the second sheet portion 35a and the fourth sheet portion 36a (that is, the first contact portion A1) and between the second sheet portion 35b and the fourth sheet portion 36b (that is, the second contact portion). A face seal portion 38 is formed in each of A2).

  Accordingly, the first seat portions 32a and 32b abut against or separate from the valve seat 22, thereby forming the first and second seal portions S1 and S2, and blocking the flow of fuel into the first injection hole 7. Or tolerate. The second seat portions 35a and 35b abut or separate from the valve seat 22 to form the third and fourth seal portions S3 and S4, and the fourth seat portions 36a and 36b further form the valve seat 22. The sixth and seventh seal portions S6 and S7 are formed by abutting or separating from each other. Therefore, in principle, since the seals are serialized by the triple structure of the two-point seal structure, it is easy to obtain high sealing performance. However, as described later, the first and second contact portions A1 and A2 When the communication passage R is provided, the fuel flow into the first injection hole 7 is blocked or allowed by the two-point seal structure outside the first and second seal portions S1 and S2. It has a configuration.

  At this time, when blocking the fuel from flowing into the first injection hole 7, the face seal portions 38 of the first and second contact parts A 1 and A 2 come into contact with the peripheral edge of the opening of the first injection hole 7. The seal surface pressure can be reduced, and each seal portion of the two-point seal structure that blocks or allows the fuel to flow into the first injection hole 7 is suppressed to a predetermined seal surface pressure value, thereby achieving high sealing performance. As well as the promotion of seat wear. Further, since the third storage chamber Q3 is provided facing the opening of the first injection hole 7, the stored fuel is immediately flowed into the first injection hole 7 to further improve the spray characteristics during micro lift. It becomes possible to make it.

  Further, a plurality of slit-shaped U-shaped grooves along the apex direction formed by the conical inclined surface are radially attached to the conical inclined surface of the contact portion A in the same manner as in the first embodiment so as to communicate with the communication path R. May be configured. The slit-shaped U-shaped groove is a case where the effective widths H1 and H2 of the first and second contact portions A1 and A2 are increased depending on the setting of the allowable surface pressure value. This is particularly effective when the flow resistance of the fuel flow from Q1, Q2 to the third storage chamber Q3 increases and the injection pressure decreases, and the first, second storage chambers Q1, Q2 and the third storage chamber Q3 In order to increase the communication area with the fuel, the fuel stored in the first and second storage chambers Q1 and Q2 flows into the first nozzle hole 7 in a large amount without any flow resistance, and is sprayed at the time of minute lift. The characteristics can be further improved. Therefore, even when the effective widths H1 and H2 of the first and second contact portions A1 and A2 are small depending on the setting of the allowable surface pressure value, the first and second storage chambers Q1 and Q2 and the third storage chamber Q3 are used. Since the communication area is expanded, it becomes easier to improve the spray characteristics at the time of micro lift.

  In the present embodiment, the contact portion A is divided into two first and second contact portions A1 and A2, and a first storage chamber Q3 is provided between the two contact portions A1 and A2 to provide a first. Although it connects with the opening part of the nozzle hole 7, the structure which divides | segments the contact part A into 2 or more many more and connects with it by the storage chamber Q may be sufficient not only in this. Further, the effective widths H1 and H2 of the first and second contact portions A1 and A2 divided into two do not necessarily have to be equal widths, and do not have to be finite widths. That is, the effective width H1 and the effective width H2 may be different from each other as long as the seal surface pressure of the contact portion A can be reduced to a predetermined surface pressure value or less. The structure which a mutual storage chamber connects may be sufficient.

This is the only difference between the first embodiment and the first embodiment, and other configurations and conditions remain unchanged. Accordingly, the same operations and effects as those of the first embodiment are obtained.
A third storage chamber is provided between the first contact portion A1 having the effective width H1 of the face seal portion 38 and the second contact portion A2 having the effective width H2 which is equal to or less than the allowable surface pressure value that suppresses the promotion of seat wear. Q3 is provided to abut against the opening peripheral edge of the first injection hole 7 to block the fuel from flowing into the first injection hole 7, and through the first and second contact parts A1 and A2, Since the communication passage R through which the fuel flows through the first and second storage chambers Q1 and Q2 and the third storage chamber Q3 is provided, a large amount of fuel stored in the first and second storage chambers Q1 and Q2 And it becomes possible to make it flow into the 1st nozzle hole 7 immediately, and to improve the spraying characteristic at the time of a micro lift more. Moreover, compared with Example 1, the structure of a valve body can be simplified and reduction of a process man-hour is attained.

[Other Examples]
The nozzle 1 of Example 1 thru | or Example 3 seals the upstream and downstream sides across the 1st injection hole 7 (outside injection hole) by the 1st valve body 10 (outside needle) of what is called a variable injection hole type nozzle. Although the present invention is applied to the seal structure, the present invention is not limited to this case. The purpose is to seal a variable nozzle type nozzle constituted by a one-point seal structure of the outer needle on the upstream side of the outer nozzle hole and the inner needle on the downstream side. You may apply to. Further, the present invention can be applied to a normal two-point seal structure other than the variable nozzle type nozzle, and similar effects can be obtained. Moreover, although the nozzle 1 of Example 1 thru | or Example 3 demonstrated the case where the fluid used a fuel, it cannot be overemphasized that it can apply also to fluids other than a fuel.

(A) is a schematic cross section which shows typically the structure of a fuel injection nozzle, a fuel injection valve, and a fuel injection apparatus, (b) is an expanded sectional view of the principal part of a fuel injection nozzle (Example 1). (A) is an enlarged configuration diagram of the main part of the fuel injection nozzle, the right half is a cross-sectional view when seated, and the left half is schematically illustrated without a cross-section when separated. (B) These are the top views which looked at the valve part of the fuel injection nozzle from the other side (Example 1). It is the elements on larger scale which show the structure of the communicating path provided in the contact part of the fuel injection nozzle (modified example of Example 1). It is a partial expanded sectional view of a valve part and a seal part which shows operation of a fuel injection nozzle, (a) at the time of injection stop, (b) at the time of valve opening of only the 1st nozzle hole, (c) at the 2nd nozzle hole (Example 1) is shown. (A) is an enlarged configuration diagram of the main part of the fuel injection nozzle, the right half is a sectional view when seated, the left half is schematically shown without a cross section, and (b) is a fuel injection nozzle. It is the top view which looked at the valve part from the other side (Example 2). (A) is an enlarged configuration diagram of the main part of the fuel injection nozzle, the right half is a sectional view when seated, the left half is schematically shown without a cross section, and (b) is a fuel injection nozzle. It is the top view which looked at the valve part from the other side (Example 3). It is an expanded sectional view of the principal part of a fuel injection nozzle, a right half shows a section at the time of seating, and a left half shows typically a section at the time of separation without a section (conventional example).

Explanation of symbols

1 Fuel injection nozzle (nozzle)
7 First nozzle hole (outer nozzle hole)
8 Second nozzle hole 9 Nozzle body 10 First valve body (outer needle)
11 Second valve body (inner needle)
22 Valve seat 38 Face seal part (contact surface)
A contact portion A1 first contact portion A2 second contact portion Q storage chamber Q1 first storage chamber (upstream storage chamber)
Q2 Second storage chamber (downstream storage chamber)
Q3 3rd storage chamber R Communication path S Seal part S1 1st seal part S2 2nd seal part S3 3rd seal part S4 4th seal part S5 5th seal part S6 6th seal part S7 7th seal part

Claims (10)

A nozzle body in which a nozzle hole is formed;
A valve body movably accommodated inside the nozzle body,
The valve body and the nozzle body are brought into contact with or separated from each other, and have a function as a seal portion that opens and closes the nozzle hole to block or allow high-pressure fluid to flow into the nozzle hole.
In the fluid ejection nozzle, the seal portion includes a first seal portion provided on the upstream side of the opening of the nozzle hole and a second seal portion provided on the downstream side of the opening.
The valve body has an abutting portion in which the valve body and the nozzle body abut in a planar shape between the first seal portion and the second seal portion when abutting on the nozzle body,
When the valve body comes into contact with the nozzle body, a storage chamber for storing a high-pressure fluid is provided between the first seal portion and the opening portion, or between the second seal portion and the opening portion. A fluid ejection nozzle formed on at least one of the two. The fluid ejection nozzle according to claim 1,
The contact portion has a slight gap formed between the contact portion and the nozzle body when the valve body and the nozzle body initially contact each other.
After the initial contact, the valve body and the nozzle body are formed so as to contact each other when the valve body approaches the nozzle body and stably contacts the nozzle body. Fluid injection nozzle. The fluid ejection nozzle according to claim 1 or 2,
The storage chamber is
An upstream storage chamber provided between the first seal portion and the opening;
A fluid ejection nozzle, comprising: a downstream storage chamber provided between the second seal portion and the opening. The fluid ejection nozzle according to claim 3,
The fluid ejection nozzle according to claim 1, wherein the storage volume of the upstream storage chamber and the storage volume of the downstream storage chamber are set to be substantially the same volume. The fluid ejection nozzle according to any one of claims 1 to 4,
When the valve body and the nozzle body are brought into contact with each other so as to block the high-pressure fluid from flowing into the nozzle hole, the high-pressure fluid passes between the storage chamber and the opening through the contact portion. A fluid ejecting nozzle having a communicating passage for circulation. The fluid ejection nozzle according to claim 5,
A plurality of the contact portions and the communication path are arranged adjacent to each other and arranged alternately. The fluid ejection nozzle according to claim 6, wherein
The fluid ejection nozzle, wherein the communication path is provided to be inclined with respect to an axial line of the valve body. The fluid ejection nozzle according to claim 6 or 7,
The contact portion is provided with the opening at an axial position of the valve body when the valve body and the nozzle body are contacted so as to block high pressure fluid from flowing into the nozzle hole. The valve body and the nozzle body are brought into contact with each other only in a region covering the entire circumference including the entire opening, and the valve body has a part of the opening cross section of the entire opening cross section of the opening. Provided to block,
The fluid ejecting nozzle, wherein a region other than the contact portion between the first seal portion and the second seal portion is formed as the storage chamber. The fluid ejection nozzle according to claim 6 or 7,
The contact portion is provided with the opening at an axial position of the valve body when the valve body and the nozzle body are contacted so as to block high pressure fluid from flowing into the nozzle hole. The valve body and the nozzle body are brought into a non-contact state in a region covering the entire circumference including the entire opening, and the valve body is formed so as not to block the entire opening cross section of the opening. A fluid injection nozzle characterized by the above. The fluid ejection nozzle according to claim 1,
The valve body includes a first valve body that opens and closes a first nozzle hole that is opened first in the nozzle hole;
The second valve body is accommodated in the first valve body, moves in the same direction as the first valve body, and opens and closes the second injection hole opened after the first injection hole.
The first valve body has the contact portion;
The fluid ejection nozzle, wherein the storage chamber is formed when the first valve body comes into contact with the nozzle body.

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