JP2009264212A - Injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injector inhibiting misalignment of a needle to a seat part of a fuel injection hole and capable of reducing dispersion among injection holes of spray of fuel injected from each injection hole and dispersion of injection quantity. <P>SOLUTION: The injector 2 including an outlet orifice plate 11 between a ceiling part 14 of a high pressure fuel chamber 8a and a cylindrical member 10 slidably supporting the needle 9. Since the outlet orifice plate 11 has a flat shape on a surface at a side contacting the ceiling part 14, and a convex curved surface at a side contacting the cylindrical member 10, the outlet orifice plate 11 and the cylindrical member 10 can move on the flat surface and the curved surface at the contact parts. Misalignment of the needle caused by working dispersion of each component is corrected when a needle 9 is seated on an injection hole seat part 19, and dispersion of sprays among injection holes and dispersion of injection quantity can be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injector.

  In recent years, in order to improve the combustibility of a diesel internal combustion engine, more complicated fuel injection control and refinement of the fuel spray particle size are required. Therefore, a common rail fuel injection device that can achieve complicated fuel injection control and refinement of the spray particle size by increasing the fuel injection pressure is widely applied to diesel internal combustion engines.

  An injector of a common rail fuel injection device includes a nozzle body into which high-pressure fuel flows from a fuel supply body, a needle that opens and closes a fuel injection hole in the nozzle body, a cylindrical member that slidably supports the needle, and a cylindrical member There are some that include a ceiling portion of a high-pressure fuel chamber that supports the end portion of this, a spring that urges the cylindrical member toward the ceiling portion, and a control chamber formed by these. This injector operates a control valve with an actuator, opens the control chamber, allows high-pressure fuel to flow out of the control chamber, and reduces the pressure in the control chamber to drive the needle to open the nozzle hole. Further, the control valve is operated, the control chamber is closed, the control chamber is filled with high-pressure fuel, and the needle is driven to increase the pressure in the control chamber to close the nozzle hole.

  Here, the contact portion between the cylindrical member and the ceiling portion of the high-pressure fuel chamber has a configuration in which the cylindrical member can move the ceiling portion in the horizontal axis direction orthogonal to the needle axis, so that the needle, the cylindrical member, It is possible to correct the seating deviation in the horizontal axis direction with respect to the nozzle hole of the needle shaft, which is caused by processing variations of parts such as the ceiling.

  An apparatus similar to the injector having such a configuration is disclosed in Patent Document 1, for example.

JP-T-2004-518906

  By the way, in recent years, a fuel injection device mounted on a vehicle performs complex fuel injection control combining a main injection and a plurality of pilots, post injections, etc. within one cycle in order to improve the fuel consumption, exhaust emission, etc. of the vehicle. There is a demand for reducing the spray particle size of the injected fuel. For this reason, the fuel pressure supplied to the injector is increasing. Along with the increase in the pressure of the supplied fuel, the control chamber formed by the ceiling portion of the high-pressure fuel chamber, the needle and the cylindrical member prevents the high-pressure fuel in the nozzle body from flowing into the control chamber from a place other than the inlet orifice. A higher sealing performance is required. Therefore, the clearance of each contact part is set very small, and very high processing accuracy is required for coaxial processing of the cylindrical member and the sliding part of the needle.

  However, it is actually that processing variation occurs when processing a cylindrical member, a needle, or the like. When the fuel injection device is assembled by a cylindrical member having a processing variation, a needle or the like, the processing variation may cause the needle to be eccentric with respect to the seat portion that opens and closes the nozzle hole. Here, the needle can be slidably supported by the cylindrical member, and the cylindrical member can be configured to support the end surface of the needle movably in the horizontal direction on the ceiling of the high-pressure fuel chamber. With such a configuration, when the needle is seated on the seat portion that opens and closes the nozzle hole, the eccentricity in the horizontal direction perpendicular to the needle shaft can be eliminated. However, since the needle is restrained by the cylindrical member, the eccentricity in the axial inclination direction is not eliminated when the needle is seated on the nozzle hole sheet portion. Due to the eccentricity of the needle in the axial inclination direction, a difference occurs in the fuel supply amount, pressure, etc., to each injection hole of the injector. Therefore, it is conceivable that the spray variation between the injection holes and the injection amount vary.

  Accordingly, the present invention provides an injector that reduces the variation between the spray nozzle holes and the variation in the injection amount by suppressing the needle eccentricity with respect to the nozzle hole sheet portion, and realizes good combustibility of the internal combustion engine. For the purpose.

  An injector of the present invention that solves this problem includes a control valve that is operated by an actuator, a nozzle hole formed at the tip, and a high-pressure fuel chamber and a ceiling formed on the base end side of the high-pressure fuel chamber inside A nozzle body formed with a fuel relief channel that is opened and closed by the control valve, a needle disposed in the high-pressure fuel chamber, a base end side of the needle, and the high-pressure fuel A cylindrical member formed with an inlet orifice into which high-pressure fuel flows from the chamber, and is disposed between the ceiling and the cylindrical member, and forms a control chamber together with the proximal end of the needle and the cylindrical member. An outlet orifice plate in which an outlet orifice for communicating the fuel relief flow path and the control chamber is formed, and the cylindrical member is biased toward the base end side And a biasing means, said outlet orifice plate is characterized by contacting with a curved surface and one of said tubular member and at least said ceiling portion (claim 1). By adopting such a configuration, it is possible to suppress the variation between the spray nozzle holes and the injection amount due to the eccentricity of the needle with respect to the fuel nozzle hole, thereby improving the combustibility of the internal combustion engine.

  In the injector of the present invention, an outlet orifice plate is disposed between the tubular member and the ceiling portion of the high-pressure fuel chamber, and the outlet orifice plate is curved with at least either the tubular member or the ceiling portion of the high-pressure fuel chamber. Adopting a configuration that makes contact with. Therefore, the cylindrical member or the outlet orifice plate itself can move in the horizontal axis direction and the needle axis tilting direction on the curved surface which is the contact portion, and the needle supported by the cylindrical member is only in the horizontal axis direction. There is no restriction on the direction of the axis tilt. Therefore, when the needle is eccentric due to processing variations of the cylindrical member or needle, when the needle is seated on the nozzle hole sheet portion, the cylindrical member or the outlet orifice plate moves on the curved surface of the contact portion. The eccentricity in the horizontal axis direction and the axis tilt direction can be corrected. Thus, the injector of the present invention can suppress the eccentricity of the needle with respect to the fuel injection hole sheet portion.

  By suppressing the eccentricity of the needle as described above, the uniformity of the supply amount and pressure of the high-pressure fuel with respect to each injection hole of the injector is maintained. Therefore, it is possible to suppress the spray variation between the nozzle holes and the injection amount, thereby improving the combustibility of the internal combustion engine.

  In particular, the injector of the present invention can include a rotation restricting means for restricting the rotation of the outlet orifice plate about a horizontal axis orthogonal to the needle axis (Claim 2).

  By setting it as such a structure, the outlet orifice provided in the outlet orifice plate can connect a control chamber and a fuel relief flow path. Therefore, even if the outlet orifice plate or the cylindrical member moves on the curved surface of the contact portion, a high-pressure fuel flow path between the control chamber and the fuel relief flow path can be secured.

  In addition, the outlet orifice plate of the injector of the present invention can be characterized by having a convex curved surface (claim 3).

  Furthermore, the outlet orifice plate of the injector of the present invention can be characterized by having a concave curved surface (claim 4).

  With such a configuration, the outlet orifice plate and the cylindrical member, or the opening of the ceiling portion of the high-pressure fuel chamber are in contact with each other with a convex or concave curved surface. Can move on a curved surface. Therefore, the axial inclination of the cylindrical member and the needle is not constrained, and the eccentricity of the needle with respect to the fuel injection hole can be suppressed even when the cylindrical member and the needle have processing variations.

  The injector of the present invention includes an outlet orifice plate that contacts at least a ceiling portion or a cylindrical member with a curved surface, so that even when there is processing variation in the cylindrical member or the needle, the needle eccentricity with respect to the seat portion of the nozzle hole Can be suppressed. Therefore, it is possible to reduce the spray hole variation and the injection amount variation, and improve the combustibility of the internal combustion engine.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a common rail fuel injection system 1 incorporating an injector 2 of the present embodiment.

  The common rail fuel injection system 1 is a system mounted on a vehicle and injects fuel for each cylinder of a multi-cylinder engine (for example, a diesel engine). The injector 2, the fuel pump 3, the common rail 4, the ECU 5, It is comprised by EDU6 etc.

  The fuel stored in the fuel tank 7 is sucked by the fuel pump 3, discharged to the common rail 4 at a high pressure, and accumulated. The fuel pump 3 is rotationally driven by a camshaft synchronized with engine rotation.

  The common rail 4 is a container for accumulating high-pressure fuel supplied to the injector 2. The fuel discharged from the fuel pump 3 is accumulated in the common rail 4 to a pressure necessary for injection, and is supplied to each injector 2 through a high-pressure pipe. The common rail 4 is provided with a pressure reducing valve 4a. The ECU 5 instructs to open the pressure reducing valve 4a when the common rail pressure output from the rail pressure sensor 4b exceeds a specified value. Then, by discharging the fuel from the pressure reducing valve 4a, the common rail pressure is always adjusted to be equal to or lower than a specified value. The fuel discharged from the pressure reducing valve 4a is returned to the fuel tank 7 through the relief pipe.

  An injector 2 is mounted on each cylinder of the engine. The high-pressure fuel supplied from the common rail 4 through the high-pressure pipe is injected and supplied into each port or cylinder of the engine by the injector 2 according to an instruction from the ECU 5. Then, the leaked fuel from the injector 2 is returned to the fuel tank 7 through the relief pipe. The details of the injector 2 will be described later.

  The ECU 5 is a computer including a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read Only Memory) that stores programs and the like, and a RAM (Random Access Memory) that stores data and the like. The ECU 5 reads detection results from a crank angle sensor, a cam angle sensor, an air flow meter, a throttle position sensor, a water temperature sensor, and the like, and controls the operation of the injector 2. Also, the operation of the common rail fuel injection control system 1 is integratedly controlled by reading the detection result of the common rail pressure sensor 4b and adjusting the common rail pressure by opening and closing the pressure reducing valve 4a.

  The EDU 6 is a drive unit that energizes an actuator (not shown) in the injector 2 based on an instruction from the ECU 5. The EDU 6 may be built in the case of the ECU 5.

  Next, a detailed configuration of the injector 2 will be described with reference to FIGS. 2 and 3. FIG. 2 is an explanatory diagram showing a schematic configuration of the injector 2 of the present embodiment. FIG. 3 is an exploded view showing the internal structure of the nozzle body 8 of the injector 2. 2 and 3 show only the configuration of the tip portion of the injector 2.

  The injector 2 includes a control valve 13 operated by an actuator, a nozzle body 8 having a high-pressure fuel chamber 8a therein, a nozzle hole 18 formed at the distal end portion of the nozzle body 8, and a base end side of the high-pressure fuel chamber 8a. Are attached to the ceiling 14, the fuel relief passage 21 that opens and closes by the control valve 13, the needle 9 that is disposed in the high-pressure fuel chamber 8 a, and the needle base end 9 a, and the high pressure A cylindrical member 10 in which an inlet orifice 16 into which high-pressure fuel flows from the fuel chamber 8 a is formed, is disposed between the ceiling portion 14 and the cylindrical member 10, and the control chamber 12 together with the needle base end portion 9 a and the cylindrical member 10. And an outlet orifice plate 11 in which an outlet orifice 17 for communicating the fuel relief passage 21 and the control chamber 12 is formed, the tubular member 10 and A spring 15 that is an urging means for urging the outlet orifice plate 11 toward the ceiling 14, a nozzle hole seat 19 on which the needle 9 is seated to open and close the nozzle hole 18, and a spring support 20 that receives the spring 15. It is the composition provided with.

  The nozzle body 8 is provided at the tip portion of the injector 2 and protrudes into the cylinder of the engine. The high-pressure fuel supplied from the common rail 4 and accumulated in the high-pressure fuel chamber 8 a inside the nozzle body 8 is injected into the engine cylinder from the injection hole 18 in accordance with an instruction from the ECU 5.

  The needle 9 provided inside the nozzle body 8 is supported by a cylindrical member 10 so that the needle base end portion 9a is slidable in the needle axis direction. When the needle 9 is seated on the nozzle hole sheet 19 at the tip of the nozzle body 8, the nozzle hole 18 is closed and fuel injection stops. Further, when the needle 9 is separated from the injection hole sheet portion 19, the injection hole 18 is opened and fuel is injected. The needle 9 moves in the valve opening direction or the valve closing direction of the nozzle hole 18 by a change in the fuel pressure in the control chamber 12 or the like.

  The needle 9 is provided with a spring support portion 20. A spring 15 is disposed between the spring support portion 20 and the tubular member 10. The restoring force of the spring 15 biases the tubular member 10 and the outlet orifice plate 11 toward the ceiling portion 14 of the high-pressure fuel chamber 8a. The spring support portion 20 may be provided on the nozzle body 8 side.

  The cylindrical member 10 that slidably supports the needle 9 includes an inlet orifice 16 on its side wall. From here, the high-pressure fuel in the high-pressure fuel chamber 8a flows into the control chamber 12, and the control valve 13 closes the fuel relief flow path 21, whereby the pressure in the control chamber 12 increases. The end surface of the cylindrical member 10 is in contact with the outlet orifice plate 11. The contact portion of the cylindrical member 10 with the outlet orifice plate 11 can be formed in a concave curved surface or a tapered shape so as to easily move on the outlet orifice plate 11 which is a convex curved surface.

  The outlet orifice plate 11 disposed between the tubular member 10 and the ceiling portion 14 includes an outlet orifice 17 penetrating from the control chamber 12 toward the ceiling portion 14. When the control valve 13 is opened, the high-pressure fuel in the control chamber 12 passes through the outlet orifice 17 and flows out to the fuel relief flow path 21 opened in the ceiling portion 14, thereby reducing the pressure in the control chamber 12. Let

  The outlet orifice plate 11 according to the present embodiment has a flat planar shape on the side in contact with the ceiling portion 14. When the outlet orifice plate 11 is in contact with the ceiling portion 14 in a plane, the outlet orifice plate 11 itself can move in the horizontal axis direction perpendicular to the needle axis on the plane of the ceiling portion 14. Accordingly, it is possible to correct the eccentricity of the needle shaft in the horizontal axis direction with respect to the nozzle hole caused by the processing variation of the parts. Further, since the ceiling portion 14 is in contact with the plane, the outlet orifice plate 11 itself is restricted from rotating around a horizontal axis perpendicular to the needle axis. The planar shape of the outlet orifice plate 11 restricts the rotation of the outlet orifice plate 11 around the horizontal axis orthogonal to the needle axis and the means for suppressing needle eccentricity in the horizontal axis direction orthogonal to the needle axis of the present invention. Corresponds to rotation regulation means. In this case, the ceiling portion 14 may have a flat planar shape, or may have a shape that facilitates movement of the outlet orifice plate 11 in the horizontal axis direction (for example, a convex shape).

  Further, the outlet orifice plate 11 has a convex curved surface on the side in contact with the tubular member 10. When the outlet orifice plate 11 and the cylindrical member 10 are in contact with each other on a curved surface, the cylindrical member 10 can move on the curved surface. This makes it possible to correct the eccentricity of the needle shaft tilting direction with respect to the nozzle hole of the needle shaft, which is caused by processing variations of parts. The convex curved surface of the outlet orifice plate 11 corresponds to a means for suppressing needle eccentricity in the needle axis direction of the present invention.

  The control chamber 12 is formed by the needle 9, the tubular member 10 and the outlet orifice plate 11. In the control chamber 12, high-pressure fuel flows from the high-pressure fuel chamber 8 a through the inlet orifice 16, and high-pressure fuel flows out to the ceiling portion 14 and the fuel relief flow path 21 through the outlet orifice 17. A control valve 13 is provided in the fuel relief channel 21. The control valve 13 is operated by an actuator (for example, an electromagnetic valve, a piezo element, etc.), and opens and closes the fuel relief channel 21.

  When the control valve 13 is open, the high-pressure fuel that has flowed from the inlet orifice 16 flows out from the fuel relief flow path 21 that opens to the ceiling portion 14 through the outlet orifice 17, so that the pressure in the control chamber 12 is low. Then, due to the pressure difference between the high-pressure fuel in the high-pressure fuel chamber 8 a and the low-pressure fuel in the control chamber 12, the needle 9 is urged in the valve opening direction of the nozzle hole 18 to open the nozzle hole 18. When the control valve 13 is closed, the high-pressure fuel that has flowed into the control chamber 12 from the inlet orifice 16 remains in the control chamber 12, so that the pressure in the control chamber 12 is equal to the pressure in the nozzle body 8. The needle 9 is biased in the valve closing direction of the nozzle hole 18 by the restoring force of the spring 15 to close the nozzle hole 18.

  When the needle 9 closes the nozzle hole 18, it is actually that the needle 9 is eccentric in the horizontal axis direction and the axis tilt direction with respect to the nozzle hole sheet portion 19 due to processing variations in each part. is there. However, in the injector 2 of the first embodiment, the outlet orifice plate 11 is on the ceiling portion 14 and the tubular member 10 is the convex shape of the outlet orifice plate 11 so that the needle 9 can be properly seated on the nozzle hole sheet portion 19. Can move on a curved surface. Since the eccentricity of the needle 9 in the horizontal axis direction and the axial inclination direction can be corrected by the above feature, the eccentricity of the needle 9 with respect to the injection hole sheet portion 19 is suppressed, and the amount of fuel supplied to each injection hole 18 of the injector 2・ It is possible to maintain the uniformity of pressure.

  As described above, the injector 2 according to the first embodiment can suppress the eccentricity of the needle 9 with respect to the nozzle hole sheet portion 19. Thereby, the variation between spray nozzles and the variation in the injection amount can be reduced, and the combustibility of the internal combustion engine can be improved.

  Next, a second embodiment of the present invention will be described. FIG. 4 is an explanatory diagram showing a schematic configuration of the injector 22 of the embodiment. In addition, about the component similar to Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  In the injector 22 according to the second embodiment, the surface of the outlet orifice plate 23 that comes into contact with the ceiling 24 is a convex curved surface. Since the outlet orifice plate 23 comes into contact with the ceiling portion 24 in a curved surface, the outlet orifice plate 23 itself can move on the ceiling portion 24 in the needle axis tilt direction. As a result, it is possible to correct the eccentricity of the needle shaft in the direction of tilting the needle shaft with respect to the injection hole of the needle shaft, which is caused by processing variations of the parts. The convex curved surface of the outlet orifice plate 23 corresponds to a means for suppressing needle eccentricity in the needle axis tilt direction of the present invention. In this case, the ceiling portion 24 can have a shape (for example, a concave shape or a tapered shape) such that the outlet orifice plate 23 can easily move.

  In addition, the outlet orifice plate 23 of the present invention has a flat planar surface on the side in contact with the tubular member 25. When the outlet orifice plate 23 and the cylindrical member 25 are in contact with each other in a plane, the cylindrical member 25 can move in the horizontal axis direction on the plane. As a result, it is possible to correct the eccentricity in the horizontal axis direction with respect to the nozzle hole of the needle shaft, which is caused by processing variations of parts. Moreover, since the cylindrical member 25 is in contact with the plane, the outlet orifice plate 23 itself is restricted from rotating about a horizontal axis perpendicular to the needle axis. The planar shape of the outlet orifice plate 23 restricts the rotation of the outlet orifice plate 23 around the horizontal axis orthogonal to the needle axis and the means for suppressing needle eccentricity in the horizontal axis direction orthogonal to the needle axis of the present invention. Corresponds to rotation regulation means. In this case, the contact portion on the cylindrical member 25 side can be formed into a planar shape, a tapered shape, or a convex curved shape according to the planar shape of the outlet orifice plate 23.

  Thus, in the fuel injection device of the second embodiment, the outlet orifice plate 23 is on the curved surface of the ceiling portion 24 and the cylindrical member 25 is the outlet orifice so that the needle 9 can be properly seated on the nozzle hole seat portion 19. It can move on the plane of the plate 23. Since the axial inclination of the needle 9 can be corrected by the above feature, the eccentricity of the needle 9 with respect to the nozzle hole seat portion 19 is suppressed, and the uniformity of the fuel supply amount, pressure, etc., to each nozzle hole 18 of the injector 22 is maintained. be able to.

  As described above, the injector 22 according to the second embodiment can suppress the eccentricity of the needle 9 with respect to the nozzle hole sheet portion 19. Thereby, the variation between spray nozzles and the variation in the injection amount can be reduced, and the combustibility of the internal combustion engine can be improved.

  Subsequently, Example 3 of the present invention will be described. FIG. 5 is an explanatory diagram showing a schematic configuration of the injector 26 of the embodiment. In addition, about the component similar to Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  The outlet orifice plate 27 according to the third embodiment has a flat surface on the side in contact with the ceiling portion 14. When the outlet orifice plate 27 is in contact with the ceiling portion 14 in a plane, the outlet orifice plate 27 itself can move on the ceiling portion 14 in the horizontal axis direction. Accordingly, it is possible to correct the eccentricity of the needle shaft in the horizontal axis direction with respect to the nozzle hole caused by the processing variation of the parts. Further, since the ceiling portion 14 is in contact with the flat surface, the outlet orifice plate 27 itself is restricted from rotating around a horizontal axis perpendicular to the needle axis. The planar shape of the outlet orifice plate 27 restricts the rotation of the outlet orifice plate 27 around the horizontal axis orthogonal to the needle axis and the means for suppressing needle eccentricity in the horizontal axis direction orthogonal to the needle axis of the present invention. Corresponds to rotation regulation means. In this case, the ceiling portion 14 may have a flat planar shape, or may have a shape that facilitates movement of the outlet orifice plate 11 in the horizontal axis direction (for example, a convex shape).

  Further, the outlet orifice plate 27 of the present invention has a concave curved surface on the side in contact with the cylindrical member 28. When the outlet orifice plate 27 and the cylindrical member 28 come into contact with each other on a curved surface, the cylindrical member 28 can move on the curved surface. This makes it possible to correct the eccentricity of the needle shaft tilting direction with respect to the nozzle hole of the needle shaft, which is caused by processing variations of parts. The concave curved surface of the outlet orifice plate 27 corresponds to the means for suppressing needle eccentricity in the needle axis direction of the present invention. In this case, the contact portion on the cylindrical member 28 side can be a convex curved surface or a tapered shape in accordance with the concave curved surface of the outlet orifice plate 27.

  As described above, in the injector 26 of the third embodiment, the outlet orifice plate 27 is on the ceiling portion 14 and the cylindrical member 28 is the concave shape of the outlet orifice plate 27 so that the needle 9 can be properly seated on the nozzle hole seat portion 19. Can move on a curved surface. Since the eccentricity of the horizontal axis direction and the axial inclination direction of the needle 9 can be corrected by the above feature, the eccentricity of the needle 9 with respect to the nozzle hole sheet portion 19 is suppressed, and the spray nozzle hole variation and the injection amount variation are reduced. The combustibility of the internal combustion engine can be improved.

  Note that the outlet orifice plate 27 of the injector 26 may have a concave curved surface on the side in contact with the ceiling portion 14 and a flat surface on the side in contact with the tubular member 28. In this case, the ceiling portion 14 in contact with the outlet orifice plate 27 can have a convex shape in accordance with the concave curved surface on the outlet orifice plate 27 side. Further, the contact portion on the cylindrical member 28 side can have a planar shape, a tapered shape, or a convex curved surface shape in accordance with the planar shape of the outlet orifice plate 27.

  Further, a fourth embodiment of the present invention will be described. FIG. 6 is an explanatory diagram showing a schematic configuration of the injector 29 of the embodiment. In addition, about the component similar to Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  In the outlet orifice plate 30 of the fourth embodiment, the surface on the side in contact with the ceiling portion 14 has a planar shape. When the outlet orifice plate 30 is in contact with the ceiling portion 14 in a plane, the outlet orifice plate 30 itself can move on the ceiling portion 14 in the horizontal axis direction. Further, since the ceiling portion 14 is in contact with the flat surface, the outlet orifice plate 30 itself is restricted from rotating around a horizontal axis perpendicular to the needle axis. The planar shape of the outlet orifice plate 30 restricts the rotation of the outlet orifice plate 30 around the horizontal axis orthogonal to the needle axis and the means for suppressing needle eccentricity in the horizontal axis direction orthogonal to the needle axis of the present invention. Corresponds to rotation regulation means. In this case, the ceiling portion 14 may have a flat planar shape, or may have a shape that facilitates movement of the outlet orifice plate 11 in the horizontal axis direction (for example, a convex shape).

  In the outlet orifice plate 30 of the present invention, the contact portion with the cylindrical member 31 has a concave curved surface. When the outlet orifice plate 30 and the cylindrical member 31 come into contact with each other on the concave curved surface, the cylindrical member 31 can move on the curved surface. This makes it possible to correct the eccentricity of the needle shaft in the tilt direction with respect to the nozzle hole of the needle shaft, which is caused by processing variations of parts. The concave curved surface of the outlet orifice plate 30 corresponds to the means for suppressing needle eccentricity in the needle axis direction of the present invention. In this case, the contact portion on the cylindrical member 31 side can be a convex curved surface or a tapered shape in accordance with the concave curved surface of the outlet orifice plate 30.

  Thus, in the injector 29 of the present invention, the outlet orifice plate 30 is on the ceiling portion 14 and the tubular member 31 is on the concave curved surface of the outlet orifice plate 30 so that the needle 9 can be properly seated on the nozzle hole sheet portion 19. Can move. The eccentricity of the needle 9 in the horizontal axis direction and the axis inclination direction can be corrected by the above feature, so that the eccentricity of the needle 9 with respect to the nozzle hole sheet portion 19 is suppressed, and the amount of fuel supplied to each nozzle hole 18 of the injector 29 Uniformity such as pressure can be maintained.

  As described above, the injector 29 of the present invention can suppress the eccentricity of the needle 9 with respect to the nozzle hole sheet portion 19. Thereby, the variation between spray nozzles and the variation in the injection amount can be reduced, and the combustibility of the internal combustion engine can be improved.

  The outlet orifice plate 30 of the injector 29 may have a concave curved surface as a contact portion with the ceiling portion 14 and a flat surface as a side in contact with the tubular member 31. In this case, the ceiling portion 14 in contact with the outlet orifice plate 30 can have a convex shape in accordance with the concave curved surface on the outlet orifice plate 30 side. Further, the contact portion on the cylindrical member 31 side can have a planar shape, a tapered shape, or a convex curved surface shape in accordance with the planar shape of the outlet orifice plate 30.

  The above embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to these, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

  For example, like the injector 32 shown in FIG. 7, the outlet orifice plate 33 has both the surface on the side in contact with the ceiling portion 34 and the surface on the side in contact with the cylindrical member 35 as convex curved surfaces. It is also possible to adopt a configuration provided with a flange portion 33a extending in the direction. In this case, the biconvex curved surface of the outlet orifice plate 33 corresponds to means for suppressing needle eccentricity in the horizontal axis direction orthogonal to the needle axis and the needle axis tilt direction of the present invention. The flange portion 33a extending in the horizontal axis direction of the outlet orifice plate 33 corresponds to a rotation restricting means for restricting the rotation of the outlet orifice plate 33 around the horizontal axis orthogonal to the needle axis. Further, the outlet orifice plate 33 of the injector 32 includes a flange portion 33a extending in the horizontal axis direction, with both the surface on the side in contact with the ceiling portion 34 and the surface on the side in contact with the tubular member 35 being concave curved surfaces. You can also take

It is explanatory drawing which showed schematic structure of the common rail type fuel injection system incorporating the injector of Example 1. FIG. It is explanatory drawing which showed schematic structure of the injector of Example 1. FIG. It is explanatory drawing which showed the structure inside the nozzle body of the injector of Example 1. FIG. It is explanatory drawing which showed schematic structure of the injector of Example 2. FIG. It is explanatory drawing which showed schematic structure of the injector of Example 3. FIG. It is explanatory drawing which showed schematic structure of the injector of Example 4. FIG. It is explanatory drawing which showed schematic structure of the injector incorporating the outlet orifice plate in which the contact part with the ceiling part of a high pressure fuel chamber and the contact part with a cylindrical member were formed in the convex curved surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Common rail type fuel injection system 2 Injector 3 Fuel pump 4 Common rail 5 ECU
8 Nozzle body 8a High pressure fuel chamber 9 Needle 9a Needle base end portion 10 Tubular member 11 Outlet orifice plate 12 Control chamber 13 Control valve 14 Ceiling portion 15 Spring 16 Inlet orifice 17 Outlet orifice 18 Injection hole 19 Injection hole seat portion 20 Spring support Part 21 Fuel relief flow path

Claims (4)

A control valve operated by an actuator;
A nozzle hole is formed at the tip, and a fuel relief flow path is formed that opens into a high-pressure fuel chamber and a ceiling formed on the base end side of the high-pressure fuel chamber and is opened and closed by the control valve. A nozzle body;
A needle disposed in the high-pressure fuel chamber;
A cylindrical member attached to the proximal end of the needle and having an inlet orifice into which high-pressure fuel flows from the high-pressure fuel chamber;
An outlet orifice is formed between the ceiling and the cylindrical member, forms a control chamber together with the proximal end of the needle and the cylindrical member, and communicates the fuel relief channel with the control chamber. An outlet orifice plate,
Urging means for urging the tubular member toward the base end side,
The injector, wherein the outlet orifice plate is in contact with at least one of the ceiling and the tubular member with a curved surface. The injector according to claim 1, wherein
An injector comprising rotation restriction means for restricting rotation of the outlet orifice plate about a horizontal axis orthogonal to the needle axis. The injector according to claim 1, wherein
The outlet orifice plate has a convex curved surface. The injector according to claim 1, wherein
The outlet orifice plate has a concave curved surface.

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