JP2017534794A - Fuel injector - Google Patents

Abstract

The present invention relates to an injector comprising an actuator, a valve (26) and a nozzle. The actuator body (22), the valve body (50), and the nozzle body are firmly connected to each other as a coaxial laminate by an injector retaining screw. The injector further comprises a device (92) for coaxially positioning the actuator body (22) and the valve body (50). The positioning device (92) has the same two main bodies (22, 50) as the radial positioning means (94) for preventing the actuator main body (22) and the valve main body (50) from moving out of alignment. Angular positioning means (96) that prevent the two from rotating relative to each other, the two positioning means (94, 96) being separate and independent.

Description

  The present invention relates to a fuel injector provided with means for aligning with a component of an injector body.

  Fuel injectors conventionally include a movable needle that slides under the influence of a differential pressure between a control chamber and an injection nozzle. The pressure in the control chamber changes under the influence of the movement of the solenoid valve, which includes an armature stem assembly that is attracted by the magnetic field of the coil and repelled by the valve spring. The needle and armature stem assembly can slide within the body of the injector, which itself is made up of several elements including an actuator body, a valve body and a nozzle body. These elements of the injector body are firmly connected to each other by an injector retaining screw, which is supported on the shoulder of the nozzle body and is screwed to the actuator body, the nozzle body and the actuator Compress the valve body with the body.

  In order to align elements of the body that need to remain coaxial, a known procedure is between two adjacent elements in a complementary mesh hole formed in each of the two adjacent elements of the body. Using two partially inserted cylindrical pins. For this reason, two eccentric and substantially diametrically opposite pins align the injector body and valve body, and similarly, two separate pins align the valve body and nozzle body. .

  This alignment with the pins is subject to manufacturing tolerances and is therefore not perfect, and the tolerances will cause some deviations, indicating that the quality improvement and the pressure required for the injectors are gradually increasing. In view of this, this deviation is no longer acceptable.

  The present invention proposes to solve these problems at least in part by proposing a fuel injector extending along the longitudinal axis and comprising an actuator, a valve and a nozzle.

  The actuator includes a main body that extends from the head to the lower surface. The actuator has a hole that opens to the lower surface, and the coil of the electromagnet is fixed to the hole. The valve includes a body that extends from the top surface to the bottom surface along a longitudinal axis, the valve is formed with a receiving portion that forms a wide low pressure chamber, and the fluid distribution hole is pivoted from the center of the bottom of the wide low pressure chamber. Extend in the direction. The valve includes a movable armature stem assembly, a magnetic armature in the form of a thick disc that moves within the low pressure chamber, and a cylindrical stem that slides within the distribution hole. The nozzle comprises a body in the form of a stepped spindle from the top surface to the closed end forming the injection nozzle. The nozzle further includes a needle disposed in an axially sliding manner within the main body.

  The actuator body, valve body and nozzle body are firmly connected to each other as a coaxial stack along the longitudinal axis by means of an injector retaining screw, which supports the outer shoulder of the nozzle body. And surrounding the valve and screwed to the actuator body, the injector further comprises a device for coaxially positioning the actuator body and the valve body.

  The positioning device includes a radial positioning means for preventing the actuator body and the valve body from moving out of a radially aligned state, and an angular positioning for preventing the same two bodies from rotating relative to each other. And the two positioning means are separate and independent.

  The radial positioning means comprises a rotating cylindrical ring, which is partially in the positioning hole formed in the valve body and partially in the complementary positioning hole formed in the actuator body. Is attached.

  Further, the positioning hole formed in the valve main body is a counter bore that forms the outer periphery of the low-pressure chamber, and the positioning hole formed in the actuator main body forms the outer periphery of the hole that opens to the lower surface of the actuator main body.

  The positioning hole formed in the valve body is attached to the low pressure chamber via a circular shoulder, and the cylindrical ring abuts and supports the circular shoulder.

  Furthermore, the cylindrical ring forms a narrow portion that opens to the lower surface of the actuator body in the hole.

  The coil is disposed in a hole in the actuator body that abuts and supports the circular edge of the ring so that the coil is pushed into the hole and the low pressure chamber extends into the actuator body. The child moves inside the actuator body.

  More specifically, on the outer surface of the coil, a reduced diameter portion and a connecting shoulder portion forming a collar portion are formed, and the collar portion is inserted into a cylindrical ring, whereby the coil is It is flush with the lower surface of the actuator body, and the magnetic armature moves inside the valve body.

  The cylindrical ring can be made from a non-magnetic metal.

  Further, the angular positioning means includes a male member, and the male member is partially formed in the actuator body at a peripheral position with respect to the hole in which the coil is disposed and into the receiving portion that opens to the lower surface of the actuator body. In addition, the valve body partially extends to a receiving portion formed in the valve body at a peripheral position with respect to the low pressure chamber and opening to the upper surface of the valve body.

  In particular, the male member is a pin, the two receptacles are two aligned holes, and the pins are inserted partially into one hole and partially into the other hole. Yes.

  Embodiments of the present invention will now be described with reference to the following drawings.

It is an axial sectional view showing an injector provided with alignment means according to the present invention. It is an enlarged detailed axial sectional view showing an area of an injector provided with the above-mentioned means generated by the first embodiment. It is an enlarged detailed axial sectional view showing an area of an injector provided with the above means generated by the second embodiment.

  FIG. 1 shows an axial cross-sectional view of a fuel injector 10 that has a longitudinal axis from an injector head 12 depicted at the top of the drawing to an injection nozzle 14 depicted at the bottom of the drawing. It extends along A1.

  For the purpose of clearly simplifying the description, the random arrangement of FIG. 1 is used, ie terms such as “top, bottom, upper, lower, upper or lower” limit the scope of the description or the invention. Can be used without.

  The injector 10 includes a head 12, in which a high-pressure inlet opening 16 and a low-pressure outlet opening 18 are arranged, and this low-pressure outlet opening is only partially visible. . The injector head 12 is firmly connected to an actuator 20 which has an actuator body 22 which itself uses an injector retaining screw 24 to the control valve 26 and to the injection nozzle 14. Is firmly connected to the main body 28 of the main body.

  The actuator body 22 is substantially a rotating cylinder having a longitudinal axis A 1 and extends from the head 12 to the lower surface 30. Further, a male screw 32 is provided on the outer cylindrical surface of the actuator main body near the lower surface 30, and this male screw is screwed to a female screw 34 which is a pair of the injector retaining screw 24. Designed to engage. Similarly, a cylindrical inner hole 36 is formed in the actuator body, and this cylindrical inner hole is coaxial with the longitudinal axis A1 but along a second axis A2 slightly shifted from the longitudinal axis. Extend. The hole 36 opens to the lower surface 30, and the coil 38 of the electromagnet 40 is fixedly disposed in the hole 36. Electrical connection means 42, such as a cable, extends along a specific conduit to a connector 44 provided with terminals that allow the coil 38 to be connected to an external control unit (not shown). Extends toward the injector head 12. The coil 38 itself is formed with a central hole 46 in which a valve spring 48 is disposed.

  The control valve 26 includes a rotating cylindrical valve body 50, which has a longitudinal axis A1 and extends between an upper surface 52 and a lower surface 54. The valve body has a second axis A2. An axial hole 56 is formed with two sections that are coaxial with each other. The first section is open to the top surface 52 and is a wide and shallow counterbore that forms a low pressure chamber 58 and the second section that forms the fluid distribution holes 62 is the low pressure chamber. It extends from the center of the bottom 60 toward the lower surface 54. Some channel inlets open laterally into the axial mekra distribution hole 62.

  Furthermore, the injector shown in FIG. 1 on which this description is based is merely a non-limiting example, and various alternative designs exist and are mentioned, although these alternatives may be omitted are claimed. Is not excluded from the scope protected by the scope. For example, just what is embodied is that the longitudinal axis A1 and the second axis A2 are separate and parallel. This misalignment was introduced by EP 1693563 and has various advantages, but is not essential and an injector with two axes coincident is present without difficulty from the suggestion of the present invention. Can be obtained.

  In addition, the control valve 26 includes an armature stem assembly 64 disposed in a manner that is movable within the axial bore 56. The assembly comprises a magnetic armature 66 and a valve stem 68, which has the overall shape of a thick disk, which is located in the low pressure chamber 58, and the valve stem 68 is of various diameters. It is a cylindrical shaft provided with a section. One end of the stem 68 is embedded in the center of the armature 66 and pressed against the armature, and is thus attached, and the valve stem 68 extends perpendicular to the armature 66 and distributes. A tight slip fit is provided in the hole 62. The valve stem 68 slides directly in the distribution hole 62 as shown in FIG. 2, or in a cylindrical sleeve with a plurality of radial holes radially drilled in an alternative, not shown, It is inserted into the distribution hole 62.

  As shown, the coil 38, the coil central hole 46, the valve spring 48, the valve body axial hole 56, the magnetic armature 66 and the valve stem 68 are coaxial and extend along the second axis A2. . The valve spring 48 is compressed between the bottom of the central hole 46 of the coil and the valve stem 68 whose head is flush with the center of the armature 66, and separates the armature stem assembly 64 from the coil 38. Energize toward the position to do.

  The injection nozzle 14 for this part comprises a nozzle body 28, a needle 70 and a needle spring 72.

  The nozzle body 28 is cylindrical, has a longitudinal axis A1, and the second wide section 78 and the second narrow section closed by the tip at the bottom end portion of the nozzle body where a plurality of injection holes are formed. 80, a stepped spindle extending downward from the upper surface 76, allowing pressurized fuel to be injected from the injector 10. The outer surfaces of the two sections 78 and 80 are connected to each other at a horizontal disk-shaped surface 82, and the injector retaining screw 24 is in contact with and supports the disk-shaped surface.

  As shown in FIG. 1, the upper surface 76 of the nozzle body is in surface contact with the lower surface 54 of the valve body, and similarly, the upper surface 52 of the valve body is in surface contact with the lower surface 30 of the actuator body. An integral hermetic laminate can be formed utilizing the injector retaining screw 24, which fits around the second narrow section 80 of the nozzle body, Abutting and supporting the disk-like surface 82 of the nozzle body and extending in the axial direction along the longitudinal axis A1, the pair of screws 32, 34 surrounding the control valve 26 and described above. Is screwed to the actuator body 22 using The surface is sealed by the mirror surface quality in the state of the contact surface and by a sufficiently high fastening torque of the retaining screw 24, which provides high compression between the bottom of the actuator body, the valve body and the nozzle body. generate.

  The needle 70 of the injector described in this example is guided in the nozzle body between the top guide part and the bottom guide part, and these top guide part and bottom guide part are incorporated in the nozzle body. Alternatively, there are a plurality of injectors whose top guide part is a part separated from the nozzle body, and the top guide part is interposed between the valve and the nozzle body in the state of a compressed laminate of such injectors. Has been.

  For the purpose of aligning the actuator body 22 and the valve body 50 coaxially along the longitudinal axis A1 and before fastening the retaining screw 24 with the risk of moving the parts out of alignment. The injector 10 is provided with a positioning device 92, which is a radial positioning means 94 for preventing the two bodies 22, 50 from moving out of alignment and one body. Angular positioning means 96 for preventing the other body from rotating relative to the other body.

  The positioning device 92 according to the first embodiment will now be described with reference to FIG.

  The radial positioning means 94 includes a cylindrical ring 98 having an inner diameter larger than the outer diameter of the magnetic armature 66 and an outer diameter equal to the diameter of the hole 36 in the actuator body.

  As can be seen, a counter bore 100 is formed on the outer periphery of the low pressure chamber 58. The outer diameter of the counter bore is the diameter of the hole 36 in the actuator body, and similarly to the outer diameter of the ring 98. Equally, the counter bore 100 extends along the second axis A2 to the shoulder 102, and the cylindrical ring 98 abuts and supports the shoulder. The ring 98 has a height that is greater than the depth of the counterbore 100, and the shoulder 102 is located at that depth relative to the upper surface 52 of the valve body and is thus disposed, and thus the ring 98 protrudes beyond the upper surface 52 of the valve body and forms a cylindrical body having a second axis A2 as its rotation axis.

  Further, a reduced diameter section that forms a collar 104 is provided on the lateral outer surface of the coil 38 at the bottom end of the coil close to the valve, and this collar 104 is slightly smaller than the inner diameter of the ring 98. The collar 104 has a diameter and a length greater than the length of the protruding portion of the ring 98, and the collar 104 is connected to the lateral surface of the body of the coil 38 via another shoulder.

  For this reason, when installed, the ring 98 aligns the counterbore 100 of the valve body 50 and the hole 36 of the actuator body along the second axis A2 via the outer cylindrical surface of the ring 98. The magnetic armature 66 moves within the low pressure chamber 58 in the center of the ring 98 and the coil collar 104 engages within the ring 98 so that the lower surface of the coil is flush with the lower surface 30 of the actuator body. become.

  Therefore, the ring 98 prevents the displacement due to the radial displacement between the actuator body 22 and the valve body 50. In contrast, the ring does not prevent the actuator body and the valve body from rotating about the second axis A2 with respect to each other, and for this purpose angular positioning means 96 are provided, this angular positioning means. Comprises a pin 106 which is inserted into a hole 108 formed in the actuator body 22 and is tightly fitted in a paired hole 110 formed in the valve body 50. Further, the pin is eccentric to the outside of the ring 98 around the actuator body 22 and the valve body 50. When positioned in this way, the two bodies 22, 50 already held by the ring 98 are likewise prevented from rotating relative to each other by the eccentric pins 106.

  Here, the second embodiment will be described with respect to the difference from the above embodiment and with reference to FIG.

  The main difference is that the coil 38 does not have a collar 104 with respect to the radial positioning means 94. Therefore, the ring 98 is inserted into the hole 36 of the actuator body, and the diameter of the hole is narrowed, so that the coil 38 is pushed into the hole 36 and abuts and supports the top of the ring 98. Therefore, the coil 38 is not flush with the lower surface 30 of the actuator body.

  As can be seen in FIG. 3, the low pressure chamber 58 occupies a predetermined space that extends partially into the valve body 50 and partially into the hole 36 of the actuator body.

  Since the coil 38 is in the retracted position inside the hole 36, the valve stem 68 is longer than the stem according to the first embodiment, and in the portion of the low pressure chamber 58 that extends into the injector body, the magnetic armature 66. Is still located as close as possible to the coil 38.

  Regardless of the embodiment, the cylindrical ring 98 can be formed of a non-magnetic metal to help maximize the magnetic force of the coil in the armature.

  Coaxially positioning the actuator body and the valve body achieved by the cooperation of separate and complementary radial positioning means and angular positioning means is likewise the valve body and nozzle body, or In the alternative mentioned, the valve body and the top guide can be used for perfect alignment.

  In addition, the injector 10 is formed with an inner channel and conduit with complementary sections between the elements of the injector, the channel and conduit forming a high voltage circuit 112 and a low pressure feedback circuit 114, which Fuel flows through the circuit during operation.

  The overall operation of the injector 10 and the various movements of the moving parts will now be briefly described.

  In the first stage, the coil 38 is not powered and the coil does not form the next time and therefore does not attract the magnetic armature 66. The valve spring 48 pulls the armature stem assembly 64 away to a position where the valve stem 68 breaks the fluid connection between the axial bore 56 and the low pressure chamber 58, thereby preventing fuel from entering the feedback circuit 114. To do. With high pressure fuel constantly entering the injector and unable to drain, the pressure increases in the control chamber 90 and pushes the needle 70 downward to a position that prevents fuel injection.

  In the second stage, the coil 38 is energized, thus generating a magnetic field that attracts the armature 66, which rises despite the biasing of the valve spring 48 and the armature is in the control chamber. And move toward the coil 38 to a position that opens the fluid connection between the low pressure chamber. Thereafter, fuel previously captured in the control chamber 90 can flow to the low pressure chamber 58 and the return circuit 114. This rapid drain creates a vacuum in the control chamber 90 that pulls the needle 70 upward into a position that allows fuel to be dispensed.

  In the description, the following reference symbols are used.

DESCRIPTION OF SYMBOLS 10 Fuel injector 12 Injector head 14 Injection nozzle 16 High pressure inlet opening 18 Low pressure outlet opening 20 Actuator 22 Actuator body 24 Injector retaining screw 26 Control valve 28 Nozzle body 30 Lower surface 32 of actuator body Male screw 34 of actuator body Female thread 36 of retaining screw 38 Hole 38 of actuator body 40 Coil 40 Electromagnet 42 Electrical connection means 44 Connector 46 Central hole 48 of coil Valve spring 50 Valve body 52 Upper surface of valve body 54 Lower surface of valve body 56 Low pressure chamber 60 Low pressure chamber bottom 62 Fluid distribution hole 64 Armature stem assembly 66 Magnetic armature 68 Valve stem 70 Injector needle 72 Needle spring 76 Nozzle body upper surface 78 First wide section 80 Second narrow section 82 Nozzle body Horizontal disk-like surface 90 Chamber 92 Positioning device 94 Radial positioning means 96 Angular positioning means 98 Tubular ring 100 Counter bore 102 on the outer periphery of the low pressure chamber Shoulder 104 on the bottom of the counter bore Collar 106 Pin 108 Hole 110 on the actuator body Valve body High voltage circuit 114 Low voltage feedback circuit A1 Longitudinal axis A2 Second axis

Claims (10)

A fuel injector (10) extending along a longitudinal axis (A1) and comprising an actuator (20), a valve (26) and a nozzle (14),
The actuator (20) includes a main body (22) extending from the head (12) to the lower surface (30), and the actuator is formed with a hole (36) that opens to the lower surface (30). 40) the coil (38) is fixed in the hole (36),
The valve (26) comprises a body (50) extending from the upper surface (52) to the lower surface (54) along the longitudinal axis (A1), the valve forming a wide low pressure chamber (58). A fluid distribution hole (62) extends axially from the center of the bottom (60) of the wide low pressure chamber, and the valve (26) is connected to the movable armature stem assembly (64). A magnetic armature (66) in the form of a thick disk-like body that moves in the low-pressure chamber (58), and a cylindrical stem (68) that slides in the distribution hole (62). ,
The nozzle (14) comprises a main body (28) in the form of a stepped spindle from the upper surface (76) to the closed end forming the injection nozzle, the nozzle being axial (A1) within the main body (28). And a needle (70) disposed in a sliding manner.
The actuator body (22), the valve body (50), and the nozzle body (28) are firmly connected to each other by a coaxial laminated body along the longitudinal axis (A1) by an injector retaining screw (24). The injector retaining screw supports an outer shoulder of the nozzle body, surrounds the valve (26), and is screwed to the actuator body (22). The injector (10) And a device (92) for coaxially positioning the actuator body (22) and the valve body (50),
A radial positioning means (94) for preventing the positioning device (92) from moving out of the aligned state of the actuator body (22) and the valve body (50), and the two body ( 22 and 50) angular positioning means (96) for preventing rotation relative to each other, the two positioning means (94, 96) being separate and independent. And fuel injector.   The radial positioning means (94) includes a rotating cylindrical ring (98), the rotating cylindrical ring partially in a positioning hole (100) formed in the valve body, and 2. The fuel injector according to claim 1, wherein the fuel injector is partially mounted in a complementary positioning hole (36) formed in the actuator body.   The positioning hole (100) formed in the valve body is a counter bore (100) that forms the outer periphery of the low-pressure chamber (58), and the positioning hole (36) formed in the actuator body is the counter bore (100). The fuel injector according to claim 2, wherein an outer periphery of the hole (36) opening to the lower surface (30) of the actuator body is formed.   The positioning hole (100) formed in the valve body is attached to the low pressure chamber (58) via a circular shoulder (102), and the cylindrical ring (98) connects the low pressure chamber. The fuel injector according to claim 3, wherein the fuel injector is abutted and supported.   The fuel injector according to claim 4, wherein the cylindrical ring (98) forms a narrow portion in the hole (36) that opens to the lower surface (30) of the actuator body.   The coil (38) is disposed in the hole (36) of the actuator body that abuts and supports the circular edge of the ring (98), whereby the coil (38) is disposed in the hole (36). The low pressure chamber (58) extends into the actuator body (22) and the magnetic armature (66) moves inside the actuator body (22). The fuel injector according to claim 5.   On the outer surface of the coil (38), a reduced diameter portion and a connecting shoulder portion forming a collar portion (104) are formed, and the collar portion (104) is inserted into the cylindrical ring (98). Thus, the coil (38) is flush with the lower surface (30) of the actuator body, and the magnetic armature (66) moves inside the valve body (50). The fuel injector according to claim 5.   The fuel injector according to any one of claims 2 to 7, wherein the cylindrical ring (98) is made of a non-magnetic metal.   The angular positioning means (96) includes a male member (106), and the male member is formed in the actuator body at a peripheral position with respect to the hole (36) in which the coil (38) is disposed. The valve main body is formed in the valve main body (50) partially in the housing portion (108) that opens to the lower surface (30) of the actuator main body and at a peripheral position with respect to the low-pressure chamber (58). 9. The fuel injector according to claim 1, wherein the fuel injector extends partially to a housing part (110) that opens to the upper surface (52) of (50).   The male member is a pin (106), the two receiving portions (108, 110) are two aligned holes, and the pin (106) is in one of the two holes. The fuel injector according to claim 9, wherein the fuel injector is inserted partially into the other hole and partially into the other hole.

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