JP4983782B2 - Fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device that supplies fuel to a combustion chamber, and is suitably applied to, for example, a fuel injection valve that injects and supplies fuel to an internal combustion engine.

As a conventional fuel injection device, a fuel injection valve that requires a centering function and a sealing function of an actuator or the like is known (see, for example, Patent Document 1). In order to support a piezo stack as an actuator, this conventional fuel injection valve has a structure in which the spherical surface portion of the actuator base is brought into contact with the funnel-shaped surface portion of the main body so as to be aligned on the combustion chamber side. Then, by screwing with a nut from the opposite side of the combustion chamber, the main body is sandwiched between the nut and the actuator base, and the actuator base is aligned and fixed with respect to the main body. Thus, the contact portion between the spherical surface portion and the funnel-shaped surface portion contributes to alignment and is also a seal portion to which stress due to tightening of a nut or the like is applied.
International Publication No. 2007/033859 A1 Pamphlet

  However, since the contact portion of the prior art is configured by contact between the spherical surface portion and the funnel-shaped surface portion, since the contact area is small, the stress concentration tends to increase further, and durability performance as a seal portion is increased. There's a problem.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a fuel injection device capable of achieving both the alignment function and ensuring the durability of the seal portion.

The present invention employs the following technical means to achieve the above object. That is, in the invention of the fuel injection device according to the first aspect, the housing is provided with the nozzle hole through which the fuel is jetted, and is provided inside the housing, and is reciprocated to open and close the nozzle hole. A valve member that allows and stops fuel injection and a housing that is extended and retracted in the axial direction to reciprocate and displace the piston, thereby controlling the internal pressure of the pressure control chamber and reciprocatingly displace the valve member. An actuator, a support member provided inside the housing to support the actuator and having a flange projecting radially outward; and a member that closes the inside of the housing from the outside, and is fastened to the support member; A lid member having a flange portion that sandwiches an end portion in the axial direction of the housing with the flange portion of the support member,
The portion of the surface where the collar portion of the lid member and the end portion in the axial direction of the housing contact is configured by a combination in which a cross section parallel to the axial direction of the housing forms a curved surface portion and an inclined surface portion.
The surface portion where the end portion of the housing in the axial direction and the flange portion of the support member come into contact with each other is configured such that a cross section parallel to the axial direction of the housing is in surface contact between the flat portions. To do.

  According to this invention, the actuator is aligned with respect to the housing by the combination of the contact surface portion that forms the curved surface portion and the inclined surface portion, and receives a load in a wide area by the surface contact between the flat surface portions, so that the inside and the outside of the housing are connected. Demonstrate the function of sealing. Thereby, since the alignment function and the sealing function are realized by separate contact portions, a fuel injection device which is superior in the durability of the sealing portion to the above-described conventional technology and can sufficiently secure both functions is obtained.

  According to a second aspect of the present invention, in the first aspect of the present invention, the portion of the surface where the collar portion of the lid member and the end portion in the axial direction of the housing are in contact, and the end portion in the axial direction of the housing The part of the surface which contacts the collar part of a supporting member is arrange | positioned so that it may rank with the axial center direction of a housing.

  According to the present invention, since the parts of the respective surfaces that come into contact with each other come to act so that the force acting on the surface contact part between the flat parts is along the axial direction of the housing, the acting force is applied to the surface contact part. I can receive it reliably. Therefore, the vibration of the actuator can be reduced.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the female screw portion provided in the lid member and the male screw portion provided in the support member are screwed together, and the lid member becomes the support member. It is characterized by being fastened. According to the present invention, since the screw portion of the lid member is arranged on the radially outer side than the screw portion of the support member, the lid member is arranged so that the distance between the screw portion of the lid member and the flange portion in the radial direction is small. Can be configured. Therefore, the shape and size of the lid member can be simplified.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also a combination of the embodiments even if they are not clearly shown unless there is a problem with the combination. It is also possible.

(First embodiment)
Hereinafter, a first embodiment as an example of a fuel injection device according to the present invention will be described with reference to FIGS. 1 and 2. The fuel injection device is, for example, a device used for a direct injection type engine that directly injects into a cylinder of a diesel engine or a direct injection spark ignition internal combustion engine (hereinafter referred to as a direct injection gasoline engine). A fuel injection valve 1 as an example of a fuel injection device is attached to a cylinder head such that an injection hole 8 formed at a tip for injecting fuel is connected to a combustion chamber in a cylinder (not shown). FIG. 1 is a longitudinal sectional view showing the configuration of the fuel injection valve 1. Hereinafter, in the present embodiment, the fuel injection valve 1 will be described as a valve for injecting high-pressure fuel distributed and supplied from a common rail as a pressure accumulating container common to each cylinder (not shown). Further, the fuel injection valve 1 according to the present embodiment can be used for a fuel injection unit that injects fuel into, for example, an intake port below the cylinder.

  As shown in FIG. 1, the fuel injection valve 1 includes a housing body 2, a nozzle body 3 that forms a housing together with the housing body 2, a needle 7 as a valve member, a needle guide cylinder 71, a piston 6, and a piston A guide cylinder 61, an actuator 5, a stack housing 10 as a support member for supporting the actuator, and a lid member 4 as a closing member for closing the housing are provided.

  The housing of the fuel injection valve 1 is composed of a housing body 2 and a nozzle body 3. The housing main body 2 is a cylindrical body that is open at both ends and mainly accommodates the stack housing 10, the actuator 5, the piston 6, and the piston guide cylinder 61 therein. The housing body 2 is connected to the nozzle body 3 at one end in the axial direction (the lower end shown in FIG. 1), and the lid member 4 at the other end in the axial direction (the upper end shown in FIG. 1). And the stack housing 10. The nozzle body 3 is a component constituting the nozzle portion of the fuel injection valve 1 and is a cylindrical body that mainly accommodates the needle 7 and the needle guide cylinder 71 therein. The nozzle body 3 has a nozzle hole 8 formed at one end in the axial direction (the lower end shown in FIG. 1), and the other end in the axial direction (the upper end shown in FIG. 1) is the nozzle body 3. To be connected to.

  The nozzle hole 8 is a pore that communicates the inner wall surface and the outer wall surface of the nozzle body 3, and the needle 7 is attached to the inner wall surface facing the nozzle hole 8 (the inner wall surface positioned at the periphery of the inlet portion of the nozzle hole 8). A seat 81 for seating is provided. A fuel reservoir 75 is formed between the needle 7 and the inner wall surface of the nozzle body 3 inside the nozzle body 3 and around the inlet portion of the nozzle hole 8. The valve seat 81 is a seating surface located on the inner wall surface between the fuel reservoir 75 and the inlet portion of the injection hole 8.

  In the housing body 2, an inflow port 21 connected to a common rail (not shown) is formed on a side surface, and a fuel passage 9 through which fuel flows is formed. The fuel passage 9 is supplied with fuel having substantially the same pressure as that inside the common rail. The fuel reservoir 75 constitutes a part of the fuel passage 9.

  The needle 7 is accommodated in the housing main body 2 so as to be reciprocally movable, and is reciprocally displaced to open and close the injection hole 8 to permit and stop the injection of fuel from the injection hole 8. The needle 7 is formed with a communication hole 74 that allows the back pressure chamber 73 communicating with the fuel passage 9 and the fuel reservoir chamber 75 to communicate with each other. The tip side surface portion 78 of the needle is a portion that is seated in contact with the valve seat 81. When the tip side surface portion 78 of the needle is separated from the state where it is seated on the valve seat 81, the fuel reservoir chamber 75 and the injection hole 8 come to communicate with each other, that is, the injection hole 8 and the fuel passage 9 are connected to the back pressure chamber. Therefore, fuel injection from the nozzle hole 8 is allowed. On the other hand, when the tip side surface portion 78 of the needle is seated on the valve seat 81, the fuel passage 9 and the injection hole 8 are blocked, and fuel injection from the injection hole 8 is stopped.

  The needle guide cylinder 71 is a cylindrical body, and one axial end (the lower end shown in FIG. 1) is in contact with the inner wall of the nozzle body 3 on the nozzle hole 8 side, and the other axial end (see FIG. 1 is fixed to the piston guide cylinder 61. The back pressure chamber 73 is brought into contact with the other end of the needle guide cylinder 71 in the axial direction and the other end in the axial direction of the piston guide cylinder 61 (the lower end shown in FIG. 1). 7 is a space formed between the end portion on the side of the counter-injection hole 8 (the other end portion in the axial center direction (the upper end portion shown in FIG. 1)). The back pressure chamber 73 communicates with the fuel passage 9 through a passage 67 that penetrates the piston guide cylinder 61.

  The outer peripheral wall of the needle 7 is in contact with the inner peripheral wall of the needle guide cylinder 71 (the needle 7 can slide in the axial direction with respect to the needle guide cylinder 71). The needle 7 is guided by a needle guide cylinder 71 so as to be reciprocally movable in the axial direction. When the needle 7 is seated on the valve seat 81, a predetermined gap is formed between the needle 7 and the other axial end of the piston guide cylinder 61. Due to this gap, the needle 7 can move from a position in contact with the valve seat 81 to a position in contact with the other axial end of the piston guide cylinder 61. That is, the maximum lift amount of the needle 7 is defined by the gap. An annular pressure control chamber 77 is formed between the outer wall of the needle 7 on the nozzle hole 8 side, the inner peripheral wall of the needle guide cylinder 71, and the inner wall surface of the nozzle body 3.

  The back pressure chamber 73 accommodates a first spring 72 as a first biasing member. The first spring 72 has one axial end (the lower end shown in FIG. 1) in contact with the needle 7, and the other axial end (the upper end shown in FIG. 1) is the piston guide cylinder 61. And urges the needle 7 in the direction toward the valve seat 81, that is, in the valve closing direction. Fuel flows into the fuel reservoir 75 from the back pressure chamber 16 through the communication hole 74.

  The piston guide cylinder 61 is guided on its inner peripheral wall so that the piston 6 can slide. The piston 6 is a cylindrical body, and includes a flange 68 that extends radially outward at one end in the axial direction of the piston 6. The piston 6 is inserted into the inner peripheral wall of the piston guide cylinder 61 from the other end side in the axial direction of the piston guide cylinder 61 toward one side in the axial direction (downward in FIG. 1). A hydraulic chamber 65 is formed between the inner peripheral wall. The outer peripheral wall of the piston 6 is in contact with the inner peripheral wall of the piston guide cylinder 61 so as to be slidable in the axial direction. The piston 6 is guided by the inner peripheral wall of the piston guide cylinder 61 so as to be reciprocally movable in the axial direction.

  A second spring 62 as a second biasing member is provided on the outer peripheral side of the piston guide cylinder 61. The second spring 62 has one end in the axial direction in contact with the piston guide cylinder 61 and the other end in the axial direction in contact with the flange portion 68 of the piston 6. ), That is, in a direction in which the volume of the hydraulic chamber 65 increases. When the piston 6 moves in the direction in which the volume of the hydraulic chamber 65 increases due to the urging force of the second spring 62, the pressure in the hydraulic chamber 65 decreases.

  A passage 63 that communicates the fuel passage 9 and the hydraulic chamber 65 is formed in the piston 6. The passage 63 is provided with a check valve 64 that closes the passage 63 with a spring biased in the other axial direction. When the volume of the hydraulic chamber 65 increases and the check valve 64 becomes negative pressure, the check valve 64 is pushed by the fuel filled in the fuel passage 9 and moves in one axial direction (direction toward the injection hole 8). Release the blockage. As a result, the fuel in the fuel passage 9 flows into the hydraulic chamber 65 through the passage 63.

  The hydraulic chamber 65 communicates with the pressure control chamber 77 by a passage 66 formed in the piston guide cylinder 61 and a passage 76 formed in the needle guide cylinder 71. As a result, when the piston 6 moves in one axial direction (direction toward the injection hole 8) and the volume of the hydraulic chamber 65 decreases and the pressure increases, the pressure is transferred to the pressure control chamber 77 through the passage 66 and the passage 76. Accordingly, the pressure in the pressure control chamber 77 is increased, and the needle 7 is moved in the other axial direction (the direction away from the nozzle hole 8) against the elastic force of the first spring 72. When the needle 7 moves in the other axial direction, the tip side surface portion 78 of the needle is separated from the state where the needle seat 7 is seated on the valve seat 81, and the nozzle hole 8 and the fuel passage 9 are connected via the back pressure chamber 73 and the like. Thus, the fuel injection from the nozzle hole 8 is allowed.

  The actuator 5 is provided on the other side in the axial direction than the piston 6 (on the side opposite to the injection hole 8). The actuator 5 has a piezo stack 51 made of a piezoelectric element that is an electric drive unit, and drives the piston 6 by expansion and contraction of the piezo stack 51. The piezo stack 51 is formed by alternately stacking piezoelectric ceramic layers such as PZT and electrode layers, and extends in the stacking direction, that is, in the axial direction of the housing body 2 when charged with electrical energy. On the other hand, the electric energy is discharged from the piezo stack 51 and contracts in the axial direction.

  The piezo stack 51 expands and contracts while the side portion is supported by the casing 52. A push rod 54 that contacts the other axial end of the piston 6 is provided at one end of the piezo stack 51 in the axial direction (the direction toward the injection hole 8). The push rod 54 gives an acting force corresponding to the expansion and contraction of the piezo stack 51 to the piston 6.

  A stack housing 10 that supports the piezo stack 51 together with the casing 52 is provided at one end in the axial direction of the piezo stack 51 (on the side opposite to the injection hole 8). The stack housing 10 has a threaded portion 101 formed at the other axial end, and a stack projecting radially outwardly toward the axial direction one side (direction toward the nozzle hole 8) from the threaded portion 101. The housing includes a flange portion 102 and an electrode passage 103 penetrating in the axial direction at the center portion for passing a lead wire connected to the electrode portion of the piezo stack 51. The lid member 4 fastened to the stack housing 10 is formed with a through-hole 43 communicating with the electrode passage 103, and the lead wire passes through the electrode passage 103 and the through-hole 43 to the outside of the housing body 2. It is taken out and connected to the drive circuit of the piezo stack 51.

  An inward protruding portion 22 that protrudes radially inward is formed at the other axial end of the housing body 2. When the threaded portion 41 of the lid member 4 is screwed (screwed) to the threaded portion 101 of the stack housing 10, the inwardly projecting portion 22 is stacked with the flange portion 42 projecting radially outward of the lid member 4. The lid member 4 and the stack housing 10 are fixed to the housing body 2 because they are sandwiched from both sides by the flange portion 102 of the housing.

  When the components of the fuel injection valve 1 are assembled, the needle 7, the needle guide cylinder 71, the piston 6 and the piston guide cylinder 61 are integrated at a predetermined position of the nozzle body 3, and the actuator The housing body 2 having 5 etc. arranged at predetermined positions is combined and fixed together. Then, by fastening the lid member 4, the other axial end portion of the housing body 2 is sandwiched between the stack housing 10 and the lid member 4, and the components are integrated and assembled.

  FIG. 2 is a partial cross-sectional view showing the alignment portion and the seal portion in the stack housing 10. A spherical surface portion 42a is formed on the side surface on one side (the lower side in FIGS. 1 and 2) in the axial direction of the flange portion 42 of the lid member. The spherical surface portion 42a is a surface portion in which the shape of the longitudinal section, which is a surface along the axial direction, is a curved surface in which the radially inner portion is located closer to the nozzle hole 8 than the radially outer portion. A funnel-shaped surface portion 22 a whose opening becomes smaller as it approaches the nozzle hole 8 is formed on the side surface on the other side in the axial center direction (the upper side in FIGS. 1 and 2) of the inward projecting portion 22 of the housing body 2. The funnel-shaped surface portion 22a is a surface portion in which the shape of the longitudinal section, which is a surface along the axial direction, is an inclined surface in which the radially inner portion is located closer to the nozzle hole 8 than the radially outer portion. With such a configuration, the portion of the surface where the collar portion 42 of the lid member and the end portion (inwardly projecting portion 22) in the axial direction of the housing body 2 are in contact is a cross section parallel to the axial direction of the housing body 2. Is configured by a combination of a spherical surface portion and an inclined surface portion.

  Further, a flat surface portion 22b is formed over the entire inner wall surface portion of the inner projecting portion 22 of the housing body 2 on one side in the axial direction (lower side in FIGS. 1 and 2), and the flange portion 102 of the stack housing is formed. A flat surface portion 102a is formed over the entire circumference on the side surface on the other side in the axial direction (upper side in FIGS. 1 and 2). The flat surface portion 22b and the flat surface portion 102a are in contact with each other and come into contact with each other as the lid member 4 is fastened to the stack housing 10, and are configured by flat surfaces that are parallel to each other. With such a configuration, the cross-section parallel to the axial direction of the housing body 2 is formed on the surface portion where the end portion (inwardly projecting portion 22) of the housing body 2 contacts the flange portion 102 of the stack housing. It is comprised by the surface contact of plane parts. Moreover, although the plane part 22b and the plane part 102a in this embodiment are planes orthogonal to the axial center direction of the housing main body 2 or the needle 7, they are planes that exhibit a predetermined inclination angle with respect to the axial direction. There may be.

  In such a configuration, when the lid member 4 is fastened to the stack housing 10, the spherical surface portion 42 a of the lid member 4 approaches the funnel-shaped surface portion 22 a of the housing body 2 as the engagement length of the screw portions increases. I will come in contact soon. When the fastening is further advanced, the spherical surface portion 42a and the funnel-shaped surface portion 22a are in contact with each other, and the contact portions of both gradually move, whereby the relative position of the lid member 4 with respect to the housing body 2 changes. Accordingly, since the relative position of the stack housing 10 integrated with the lid member 4 changes, the relative position of the actuator 5 with respect to the housing body 2 is displaced to a predetermined position, and the actuator 5 moves to the housing body 2. It is aligned with it.

  As the alignment process proceeds, the flat surface portion 22b of the housing body 2 and the flat surface portion 102a of the stack housing 10 come into close contact with each other, and a force acts between them. The force acting between the two is due to the force due to the fastening of the lid member 4 and the internal pressure of the fuel existing in the fuel passage 9. When the lid member 4 is fastened, a force pressing the funnel-shaped surface portion 22a from the spherical surface portion 42a acts, and a force pushing the planar portion 102a of the stack housing 10 against the planar portion 22b of the housing body 2 acts. Furthermore, the force which pushes the collar part 102 of a stack housing upward acts with the internal pressure of a fuel. Since these forces act on the seal portion, which is a surface contact portion between the flat portions constituted by the flat portion 22b and the flat portion 102a, a large stress is applied to the seal portion, and it is required to withstand this for a long time. .

  In the present embodiment, since the seal portion is formed by adhesion between flat surfaces, the contact area is large, and stress is received at this contact area, so that stress concentration can be reduced and the stress peak in the seal portion is reduced. can do.

  Furthermore, the contact portion between the spherical surface portion 42a and the funnel-shaped surface portion 22a and the contact portion between the flat surface portion 22b and the flat surface portion 102a are preferably arranged side by side along the axial direction in these longitudinal sections. That is, preferably, as shown in FIG. 2, the lid member collar 42, the stack housing collar 102, and the housing body so that both contact portions are located on the imaginary line X (axial direction) of FIG. 2. The relative positional relationship of the inward projecting portion 22, the radius of curvature of the spherical surface portion 42 a (the degree of curvature), the inclination angle of the funnel-shaped surface portion 22 a, and the radial lengths of both flat surface portions 22 b and 102 a are set. That is. By adopting such a configuration, since the force acting between the flat surface portion 22b and the flat surface portion 102a gathers in the vicinity of the imaginary line X, the acting force can be reliably received at the seal portion. It can also contribute to reducing the deflection of the actuator 5.

  Next, the operation of the fuel injection valve 1 in the above configuration will be described. When the piezo stack 51 is not charged, the piezo stack 51 is contracted. At this time, since the piston 6 is urged upward in FIG. 1 by the second spring 62, the pressure in the hydraulic chamber 65 is not high, and the pressure in the pressure control chamber 77 communicating with the hydraulic chamber 65 is also equal. Further, the pressure of the fuel in the fuel passage 9 also acts on the back pressure chamber 73, and the needle 7 is pushed downward in FIG. 1 by this pressure. Therefore, the force of the needle 7 urged downward in FIG. 1 by the first spring 72 and the pressure by the fuel in the back pressure chamber 73 rather than the force pushed upward in FIG. Since it is larger, it moves downward in FIG. 1, and the tip side surface portion 78 of the needle is in contact with the valve seat 81 and is seated. Therefore, when the piezo stack 51 is not charged, fuel injection from the nozzle hole 8 is stopped.

  When charging of the piezo stack 51 is started, the piezo stack 51 extends, and the piston 6 moves downward in FIG. 1 against the urging force of the second spring 62 by the push rod 54. As the piston 6 moves, the fuel in the hydraulic chamber 65 is pressurized, and the pressure in the pressure control chamber 77 communicating with the hydraulic chamber 65 increases. And the force which pushes the needle 7 upward of FIG. 1 by the pressure of the pressure control chamber 77 becomes large. When the force pushing the needle 7 upward in FIG. 1 becomes larger than the urging force of the first spring 72 and the like, the needle 7 moves upward in FIG. 1 and the tip side surface portion 78 of the needle moves away from the valve seat 81. As a result, the nozzle hole 8 is opened, and the fuel in the back pressure chamber 73 flows from the fuel reservoir chamber 75 to the nozzle hole 8 through the communication hole 74. Therefore, when the piezo stack 51 is charged, the nozzle hole 8 is opened and fuel is injected from the nozzle hole 8.

  When discharging starts after the piezo stack 51 is charged, the piezo stack 51 contracts. As the piezo stack 51 contracts, the piston 6 moves upward in FIG. 1 together with the piezo stack 51 by the urging force of the second spring 62. As the piston 6 moves upward in FIG. 1, the hydraulic pressure in the hydraulic chamber 65 decreases and the pressure in the pressure control chamber 77 also decreases. When the force that pushes the needle 7 upward in FIG. 1 due to the pressure in the pressure control chamber 77 becomes smaller than the urging force of the first spring 72 and the like, the needle 7 moves downward in FIG. Sits on the valve seat 81 again. Accordingly, the communication between the fuel reservoir chamber 75 and the nozzle hole 8 is closed, and the fuel injection from the nozzle hole 8 ends.

  The effect which the fuel injection valve of this embodiment brings is described. The fuel injection valve 1 is provided inside the housing body 2, supports the actuator 5, and has a stack housing 10 having a flange protruding radially outward, and closes the inside of the housing body 2 from the outside. And a lid member 4 having a flange 42 that is fastened to 10 and sandwiches the inward protruding portion 22 of the housing body 2 with the flange 102 of the stack housing. And the part of the surface where the collar part 42 of the lid member and the inwardly projecting part 22 of the housing body 2 come into contact is configured by a combination in which a cross section parallel to the axial direction of the housing forms a curved surface part and an inclined surface part. . Furthermore, the cross section parallel to the axial direction of the housing of the surface portion where the inward projecting portion 22 of the housing body 2 and the flange portion 102 of the stack housing contact each other is configured by surface contact between the flat portions.

  In the configuration having a contact portion that serves both as a centering function and a sealing function as in the prior art described above, a large load is applied to the inclined surface portion due to the wedge effect, and the curved surface portion and the inclined surface portion are in contact with each other. The stress peak becomes large, and the surface portion is liable to deteriorate, resulting in a durability problem. Here, the wedge effect means that the curved surface portion and the inclined surface portion are in line contact with each other, and the load applied to the point on the curved surface portion in the cross section parallel to the axial direction of the housing body 2 is supported by the inclined surface portion. This is an effect that the force line is firmly fixed at the line contact portion with the inclined surface portion without being dispersed, and the curved surface portion bites into the inclined surface portion.

  According to this embodiment, the actuator 5 is aligned with respect to the housing body 2 by a combination of the contact surface portion that forms the curved surface portion and the inclined surface portion, compared with such problems of the prior art. It is possible to receive a load over a wide area by surface contact. For this reason, while being able to receive a high surface pressure load, the seal part in which the peak of the stress in a contact part is not high can be provided. Therefore, the function of sealing the inside and the outside of the housing body 2 on the high pressure side can be sufficiently exhibited. Thus, in this embodiment, the alignment function and the sealing function are realized by separate contact portions. Therefore, the fuel injection valve 1 can be obtained in which the durability or reliability of the seal portion is superior to the above-described conventional technology and both functions can be sufficiently secured.

  In addition, a high surface pressure load can be received by the seal portion between the flat portions that are separate from the aligning function, and the perpendicularity of the power transmission member such as the piezo stack 51 and the piston 6 can be easily specified. Stable behavior can be realized.

  Further, the fuel injection valve 1 is configured such that the internal thread portion provided on the lid member 4 and the external thread portion provided on the stack housing 10 are screwed together so that the lid member 4 is fastened to the stack housing 10. . According to this configuration, since the screw portion 41 of the lid member 4 is disposed radially outside the screw portion 101 of the stack housing 10, the screw portion 41 and the flange portion 42 of the lid member 4 are connected as much as possible in the radial direction. Can be placed close together. Therefore, the length of the lid member 4 in the radial direction can be shortened, the shape of the lid member 4 can be simplified and miniaturized, and productivity can be increased. Moreover, since it is not necessary to arrange the screw part 41 of the lid member 4 on the radially inner side of the screw part 101 of the stack housing 10, the through hole 43 through which the lead wire passes can be formed large.

(Second Embodiment)
2nd Embodiment demonstrates the other form about the alignment part and seal part in a fuel injection valve according to FIG. FIG. 3 is a partial cross-sectional view showing the alignment portion and the seal portion in the fuel injection valve of the present embodiment. In FIG. 3, the components given the same reference numerals as those in the drawing described in the first embodiment are the same components and have the same effects.

  As shown in FIG. 3, the present embodiment is different from the first embodiment in the relationship relating to the fastening between the lid member 4A and the stack housing 10A. Specifically, since the screw portion 41 of the lid member 4A is a male screw and the screw portion 101 of the stack housing 10A is a female screw, the screwing relationship is such that the lid member 4A is male and the stack housing 10A is female. It has become. Even in such a configuration, the alignment portion (contact relationship between the spherical surface portion 42a and the funnel-shaped surface portion 22a) and the seal portion (contact relationship between the flat surface portion 22b and the flat surface portion 102a) are the same as in the first embodiment. By providing the above, the same operational effects can be achieved.

(Other embodiments)
In the above-described embodiment, the preferred embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. It is.

  In the above-described embodiment, a spherical surface portion is provided on the collar portion 42 of the lid member, and a funnel-shaped surface portion having an inclined cross section is provided on the inward projecting portion 22 of the housing body 2. However, the embodiment is limited to such a form. It is not something. The point is that the portion of the surface where the flange portion 42 of the lid member and the inwardly projecting portion 22 of the housing main body 2 come into contact is configured by a combination in which the cross section parallel to the axial direction of the housing forms a curved surface portion and an inclined surface portion. Just do it. For example, a spherical surface portion may be provided in the housing body 2 and a conical surface portion having a sloped cross section may be provided in the lid member 40.

It is a longitudinal cross-sectional view which shows the structure of the fuel injection valve which concerns on 1st Embodiment. It is a fragmentary sectional view which shows the alignment part and seal part in the stack housing of a piezo stack. It is a fragmentary sectional view which shows the alignment part and seal part in the fuel injection valve of 2nd Embodiment.

Explanation of symbols

1 ... Fuel injection valve 2 ... Housing body (housing)
3. Nozzle body (housing)
4 ... Lid member 5 ... Actuator 6 ... Piston 7 ... Needle (valve member)
8 ... Injection hole 10 ... Stack housing (support member)
22 ... inward protrusion (end of the housing in the axial direction)
22a ... funnel-shaped surface (inclined surface)
22b ... plane part 41 ... screw part (male screw part)
42 ... The buttock (buttock) of the lid member
42a ... spherical surface (curved surface)
77 ... Pressure control chamber 101 ... Screw part (female screw part)
102: The collar part of the stack housing (the collar part of the support member)
102a ... plane part

Claims (3)

A housing having a nozzle hole through which fuel is ejected;
A valve member provided inside the housing, reciprocally displaced to open and close the nozzle hole, and to permit and stop the ejection of the fuel from the nozzle hole;
An actuator that is provided inside the housing and that reciprocates and displaces the piston in the axial direction to control the internal pressure of the pressure control chamber and to reciprocate the valve member;
A support member provided inside the housing for supporting the actuator and having a flange projecting radially outward;
A lid member that closes the inside of the housing from the outside and has a flange that is fastened to the support member and sandwiches an end portion in the axial direction of the housing between the flange of the support member When,
With
The portion of the surface where the flange portion of the lid member and the end portion in the axial direction of the housing contact each other is configured by a combination in which a cross section parallel to the axial direction of the housing forms a curved surface portion and an inclined surface portion.
The portion of the surface where the end portion of the housing in the axial center direction and the flange portion of the support member come into contact with each other is configured such that a cross section parallel to the axial direction of the housing is a surface contact between the flat portions. A fuel injection device.   The portion of the surface where the flange portion of the lid member contacts the axial end portion of the housing, and the portion of the surface where the axial end portion of the housing contacts the flange portion of the support member The fuel injection device according to claim 1, wherein the fuel injection devices are arranged so as to be aligned in an axial direction of the housing.   The female screw part provided in the lid member and the male screw part provided in the support member are screwed together, and the lid member is fastened to the support member. The fuel injection device described.

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