FUEL INJECTION VALVE

Abstract

A fuel injector comprises a needle (20) (a valve body), a fixed core (13), a movable core (30), a first spring element (SP1) (a spring element), and a cup (50) (a valve closing force transmission element). The movable core has a first core contact surface (32c) that contacts the valve body when the movable core is moved a predetermined distance away from a nozzle opening, and a second core contact surface (32b) that contacts the cup when the movable core is moved away from the nozzle opening. The movable core, cup, and needle form a fuel storage chamber B1, which is surrounded by the movable core, cup, and needle for collecting fuel. The first core contact surface is located inside the fuel storage chamber.A section of the cup, which contacts the second core contact surface, separates an inner and an outer side of the fuel storage chamber, and the first core contact surface and the second core contact surface have a communication groove (32e) through which the inner and outer sides of the fuel storage chamber communicate with each other. As a result, variation in the fuel injection quantity can be reduced while simultaneously adopting a core boost structure.

Description

CROSS-REFERENCE TO SIMILAR REGISTRATIONS

[0001] This application is based on Japanese patent application No. 2017-189883, filed on September 29, 2017, and on Japanese patent application No. 2018-169993, filed on September 11, 2018, and includes their disclosures. Technical field

[0002] The present disclosure relates to a fuel injector that injects fuel. BACKGROUND

[0003] A conventional fuel injector comprises a fixed core that, when a coil is energized, generates a magnetic attraction; a movable core that is attracted and moved by the fixed core; and a valve body that is actuated by the movable core to open the valve, allowing fuel to be expelled from a nozzle orifice. In recent years, fuel pressures have increased, and the valve closing force pressing on the valve body has tended to increase. Therefore, a large valve opening force is required to open the valve against the large valve closing force.

[0004] As a countermeasure to the points mentioned above, patent literature 1 discloses a core boost structure or core thrust structure described below. This means that, for the valve opening process of the valve body, the movement of the movable core is initially started in a state where the movable core is not engaged with the valve body. Then, when the movable core is moved a predetermined distance, it is brought into contact with the valve body to initiate the valve opening process.

[0005] According to the core boost structure described above, since the moving core is not yet engaged with the valve body immediately after the start of excitation, and is not subject to the force of fuel pressure, the moving core can rapidly increase its speed of movement through an initially small magnetomotive force. Because the moving core then comes into contact with the valve body and begins the valve opening process when the speed of movement becomes sufficiently high—that is, when the moving core has traveled the predetermined distance—the valve opening process can be carried out by means of a collision force of the moving core in addition to a magnetic attraction force. Therefore, the valve opening process can be carried out even at high fuel pressure. Furthermore, the magnetic attraction force required to open the valve can be reduced.

[0006] Further state of the art is described in DE 11 2016 004 490 T5 (D1) and EP 1 801 409 A1 (D2). LITERATURE ON THE STATE OF TECHNOLOGY PATENT LITERATURE

[0007] Patent Literature 1: JP 2013-104340 A SUMMARY OF THE INVENTION

[0008] In the core boost structure described above, the movable core moves in two stages: a movement from the start of excitation until contact with the valve body; and a subsequent movement while maintaining contact with the valve body. This leads to the new problem that a change in the time interval from the start of excitation to the start of the valve opening process is directly related to a change in the amount of fuel injected during the valve opening process. Furthermore, it is important not only to reduce the time interval from the start of excitation until the valve opens, but also the time interval from the end of excitation until the valve closes.

[0009] The purpose of the present disclosure is to provide a fuel injector that uses a core boost structure while simultaneously reducing variation in the amount of fuel injected.

[0010] According to a first aspect of the present disclosure, a fuel injector comprises the following: a valve body comprising a nozzle hole ora nozzle opening for injecting fuel; a solid core that generates a magnetic attraction when a coil is energized; a movable core that is attracted by the solid core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when moved a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element that is elastically deformed by the valve opening operation of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing operation; and a valve closing force transmission element that is movable relative to the valve body and transmits the elastic valve closing force to the valve body by moving relative to the nozzle opening and contacting or touching the valve body.The movable core comprises a first core contact surface that contacts the valve body at the predetermined distance as the movable core moves away from the nozzle opening, and a second core contact surface that contacts the valve closing force transmission element as it moves away from the nozzle opening. The movable core, the valve closing force transmission element, and the valve body form a fuel storage chamber in which fuel accumulates when the valve body closes the nozzle opening. The fuel storage chamber is surrounded by the movable core, the valve closing force transmission element, and the valve body. The first core contact surface is located within the fuel storage chamber. A portion of the valve closing force transmission element that contacts the second core contact surface separates an interior space of the fuel storage chamber from an exterior space.The first core contact surface and the second core contact surface have a communication groove through which the interior of the fuel storage chamber communicates with the exterior.

[0011] In short, the fuel injector, from its first aspect, has a core-boost structure in which the moving core contacts a valve body at the point when the moving core is moving a predetermined distance away from the nozzle opening to open the valve. The fuel injector includes the valve closing force transmission element, which contacts the valve body to transmit an elastic force to the valve body by moving relative to the valve body towards the nozzle opening. The first core contact surface and the second core contact surface of the moving core feature the communication groove. The inner and outer surfaces of the fuel storage chamber, which are surrounded by the moving core, the valve closing force transmission element, and the valve body, communicate with each other through the communication groove.

[0012] When the fuel in the fuel storage chamber is compressed as the moving core moves away from the nozzle opening, the core's movement is blocked. Consequently, the core's velocity at the point of contact with the valve body over the predetermined travel distance is reduced. This diminishes the aforementioned effect of the core boost structure, which allows the valve body to open even at high fuel pressure, while reducing the magnetic attraction required to open the valve. Furthermore, because the moving core's movement is restricted, the valve body's opening timing and the fuel injection quantity become more variable.

[0013] On the other hand, according to the first aspect described above, since the inner and outer surfaces of the fuel storage chamber communicate with each other via the communication groove, the fuel accumulated in the fuel storage chamber flows outwards through the communication groove when the movable core moves away from the nozzle opening. Therefore, the compression of the fuel accumulated in the fuel storage chamber is reduced, allowing the movable core to move freely. For this reason, a reduction in the collision speed of the movable core can be prevented, thus promoting the effect of reducing the magnetic attraction force through the core boost structure. Furthermore, because the movable core moves freely, variations in the valve body opening timing, and consequently variations in the fuel injection quantity, can be reduced.

[0014] According to the first aspect, the communication groove is provided in the movable core, whereas in the patent literature described above, the communication groove is provided in a receiving element for the flange section. However, if the communication groove is provided in the valve closing force transmission element as described above, the communication groove is gradually covered by the wall surface of the valve body as the movable core moves away from the nozzle opening. Thus, the cross-sectional area of ​​the communication groove is gradually reduced, and a function that allows fuel to flow outwards from the fuel storage chamber is not adequately demonstrated.

[0015] On the other hand, in the first aspect, since the communication groove is provided in the moving core, the cross-sectional area of ​​the communication groove is maintained without decrease, even when the moving core contacts the valve body, as well as during a period in which the moving core moves a predetermined distance away from the nozzle opening. For this reason, the function of allowing the fuel to flow outwards from the fuel storage chamber can be adequately represented, and a decrease in the collision velocity force of the moving core can be sufficiently reduced.

[0016] According to a second aspect of the present disclosure, a fuel injector comprises the following: a valve body which has a nozzle hole ora nozzle opening for injecting fuel; a solid core that generates a magnetic attraction when a coil is energized; a movable core that is attracted by the solid core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when the movable core is moved a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element that is elastically deformed by the valve opening operation of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing operation; and a valve closing force transmission element that is movable relative to the valve body and transmits the elastic valve closing force to the valve body by moving relative to the nozzle opening and contacting the valve body.The movable core, the valve closing force transmission element, and the valve body form a fuel storage chamber in which fuel accumulates when the valve body closes the nozzle orifice. The fuel storage chamber is surrounded by the movable core, the valve closing force transmission element, and the valve body. The valve body has an internal passage through which the fuel flows to the nozzle orifice. The valve body has a connecting port through which the fuel storage chamber communicates with this internal passage.

[0017] In short, according to the second aspect, the fuel injector has a core-boost structure in which the moving core contacts the valve body at the point when the moving core is moving a predetermined distance away from the nozzle openings to open the valve. During the valve closing process, the valve closing force transmission element moves relative to the valve body towards the nozzle opening to contact the valve body and transmit an elastic force to it. The valve body has a connecting port through which the internal passage provided inside the valve body communicates with the fuel storage chamber.

[0018] As the movable core moves away from the nozzle opening, the fuel accumulated in the fuel storage chamber flows outwards through the connecting opening. This reduces the compression of the fuel accumulated in the fuel storage chamber, allowing the movable core to move freely. As in the first embodiment, this reduces the collision speed of the movable core, thereby increasing the effect of the core boost structure on reducing the magnetic attraction force. Furthermore, because the movable core moves freely, variations in the valve body opening timing, and consequently variations in the fuel injection quantity, are reduced.

[0019] According to a third aspect of the present disclosure, a fuel injector comprises the following: a valve body which has a nozzle hole ora nozzle opening for injecting fuel; a solid core that generates a magnetic attraction when a coil is energized; a movable core that is attracted by the solid core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when moved a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element that is elastically deformed by the valve opening operation of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing operation; and a valve closing force transmission element that is displaceable relative to the valve body and transmits the elastic valve closing force to the valve body by sliding in the direction of the nozzle opening and contacting the valve body.The movable core, the valve closing force transmission element, and the valve body form a fuel storage chamber in which fuel accumulates when the valve body closes the nozzle orifice. The fuel storage chamber is surrounded by the movable core, the valve closing force transmission element, and the valve body. The valve body has a valve body-side sliding surface on which the valve closing force transmission element slides. The valve closing force transmission element has a transmission element-side sliding surface on which the valve body slides. The valve body-side sliding surface or the transmission element-side sliding surface has a sliding surface communication groove through which an interior of the fuel storage chamber communicates with an exterior space.

[0020] In short, according to the third aspect, the fuel injector has a core boost structure in which the moving core contacts the valve body at the point in time when the moving core is moving away from the nozzle openings by the predetermined distance to open the valve. During the valve closing process, the valve closing force transmission element moves relative to the valve body in the direction of the nozzle opening to contact the valve body and transmit an elastic force to the valve body. The sliding surface communication groove, through which the inner and outer surfaces of the fuel storage chamber are connected, is provided on the valve body-side sliding surface on which the valve closing force transmission element slides, or on the transmission element-side sliding surface of the valve closing force transmission element on which the valve body slides.

[0021] As the movable core moves away from the nozzle opening, the fuel accumulated in the fuel storage chamber flows out through the sliding surface communication groove. This reduces the compression of the fuel accumulated in the fuel storage chamber, allowing the movable core to move freely. As in the first embodiment, this reduces the collision speed of the movable core, thereby increasing the effect of reducing the magnetic attraction force through the core boost structure. Furthermore, because the movable core moves freely, variations in the valve body opening timing, and consequently variations in the fuel injection quantity, are reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a sectional view of a fuel injector according to a first embodiment. Fig. Figure 2 is an enlarged view of a nozzle opening section of Fig. 1. Fig. Figure 3 is an enlarged view of a moving core section of Fig. 1. Fig. Figure 4 is a schematic representation of the function or operation of the fuel injection valve according to the first embodiment, wherein (a) in Fig. 4 a closed state of the valve, (b) in Fig. 4 a state in which a movable core, moving by a magnetic attraction, collides with a valve body, and (c) in Fig. Figure 4 shows a state in which the movable core, which continues to move due to the magnetic attraction, collides with a guide element. Fig. 5 is a timing diagram showing the operation of the fuel injector according to the first embodiment, wherein (a) in Fig. 5 a change in a drive impulse, (b) in Fig. 5 a change in a drive current, (c) in Fig. 5 a change in a magnetic attraction force and (d) in Fig. 5 shows the behavior of a moving section. Fig. Figure 6 is a flowchart showing an assembly process of the movable section according to the first embodiment. Fig. Figure 7 is an exploded view of a movable section according to the first embodiment. Fig. Figure 8 is a sectional view of the moving section, showing the state of the pressing process of a cup against a needle during the assembly process of Fig. 6 shows. Fig. Figure 9 is a sectional view of the moving section, showing a state in which an initial interference fit of the Fig. 6 is completed. Fig. 10 is a perspective view of Fig. 9. Fig. Figure 11 is a stress-strain diagram of the needle and a sleeve according to the first embodiment. Fig. Figure 12 is a sectional view showing the shape of a communication groove provided in the movable core according to the first embodiment. Fig. 13 is a top view of the in Fig. Figure 12 shows the movable core as seen from a side opposite a nozzle opening. Fig. 14 is a sectional view along a line XIV-XIV of Fig. 13. Fig. 15 is a sectional view showing modification B1 in relation to Fig. 12 shows. Fig. 16 is a top view of the in Fig. 15 movable core shown, viewed from the side opposite the nozzle opening. Fig. 17 is a sectional view of modification B2 in relation to Fig. 12. Fig. 18 is a top view of the in Fig. 17 shown movable core, viewed from the side opposite the nozzle opening. Fig. 19 is a sectional view showing modification B3 in relation to Fig. 12 shows. Fig. 20 is a top view of the in Fig. 19 shown movable core, viewed from the side opposite the nozzle opening. Fig. 21 is a sectional view showing the B4 modification in relation to Fig. 12 shows. Fig. 22 is a sectional view showing the B5 modification in relation to Fig. 12 shows. Fig. 23 is a sectional view showing the B6 modification in relation to Fig. 12 shows. Fig. Figure 24 is a sectional view showing the shape of a feed flow channel provided in a needle according to the first embodiment. Fig. 25 is a top view of the in Fig. 24 Needle shown, viewed from the side opposite the nozzle opening. Fig. 26 is a sectional view along a line XXVI-XXVI of Fig. 25. Fig. 27 is a sectional view showing modification C1 compared to Fig. 26 shows. Fig. 28 is a sectional view showing the C2 modification in relation to Fig. 26 shows. Fig. 29 is a sectional view showing the C3 modification in relation to Fig. 26 shows. Fig. Figure 30 is a top view of the needle from the side opposite the nozzle opening, which represents the C4 modification in relation to Fig. 25 shows. Fig. Figure 31 is a top view of the needle from the side opposite the nozzle opening, which represents the C5 modification in relation to Fig. 25 shows. Fig. 32 is a sectional view through the Fig. 31, and (a) is a section along a line XXXIIa-XXXIIa and (b) is a section along a line XXXIIb-XXXIIb. Fig. 33 is a sectional view of modification C6 in relation to Fig. 24. Fig. 34 is a sectional view showing the C7 modification in relation to Fig. 24 shows. Fig. 35 is a top view of a Fig. Plate 34 shown, viewed from the side of the nozzle opening. Fig. Figure 36 is a cross-sectional view showing the shape of a recessed surface provided in a guide element at the time of complete lifting according to the first embodiment. Fig. Figure 37 is a sectional view showing the shape of the recessed area that was provided in the guide element at the time of closing the valve according to the first embodiment. Fig. Figure 38 is a sectional view showing a gap between a movable core and a holder at the time of closing the valve according to the first embodiment. Fig. 39 is a top view of the in Fig. 38 Needle shown, viewed from the side opposite the nozzle opening. Fig. 40 is a sectional view showing the modification E1 in relation to Fig. 38 shows. Fig. 41 is a sectional view showing the modification E2 in relation to Fig. 38 shows. Fig. 42 is a sectional view showing the E3 modification in relation to Fig. 38 shows. Fig. Figure 43 is a sectional view of a fuel injector according to a second embodiment. Fig. Figure 44 is a sectional view of a fuel injector according to a third embodiment. DETAILED DESCRIPTION

[0022] Several embodiments for implementing the present disclosure are described below with reference to the drawings / figures. In each embodiment, a part corresponding to an item described in a previous embodiment may be assigned the same reference numeral, and the superfluous description for the part may be omitted. If only one part of a configuration is described in an embodiment, another previous embodiment may be applied to the other parts of the configuration. The parts may be combined, even if it is not expressly stated that the parts may be combined. The embodiments may be partially combined, even if it is not expressly stated that the embodiments may be combined, provided that the combination is harmless. (First embodiment)

[0023] A in Fig. The fuel injector 1 shown is attached to a cylinder head or cylinder block of an internal combustion engine mounted on a vehicle. Gasoline fuel accumulated in a vehicle-mounted fuel tank is pressurized by a fuel pump (not shown) and supplied to a fuel injector 1, and the supplied high-pressure fuel is injected directly from the nozzle openings 11a provided in the fuel injector 1 into a combustion chamber of the internal combustion engine.

[0024] The fuel injector 1 comprises a nozzle opening body 11, a main body 12, a solid core 13, a non-magnetic element 14, a coil 17, a support element 18 or a bearing element 18, a first spring element SP1, a second spring element SP2, a needle 20, a movable core 30, a sleeve 40, a cup 50, a guide element 60, and similar components. The nozzle opening body 11, the main body 12, the solid core 13, the support element 18 or the bearing element 18, the needle 20, the movable core 30, the sleeve 40, the cup 50, and the guide element 60 are made of metal.

[0025] As in Fig. As shown in Figure 2, the nozzle body 11 has multiple nozzle holes 11a for injecting fuel. The needle 20 is located inside the nozzle body 11, and a flow channel 11b, which allows high-pressure fuel to flow to the nozzle openings 11a, is provided between an outer circumferential surface of the needle 20 and an inner circumferential surface of the nozzle body 11. A housing-side seat 11s, on which a valve-body-side seat 20s formed on the needle 20s is separated, is located on the inner circumferential surface of the nozzle body 11. The valve-body-side seat 20s and the housing-side seat 11s are shaped such that they extend annularly around an axis C of the needle 20. When the needle 20 is detached and sits on the body-side seat 11s, the flow channel 11b is opened and closed and the nozzle openings 11a are opened and closed.

[0026] The main body 12 and the non-magnetic element 14 are cylindrical in shape. A cylindrical end section of the main body 12, located closer to the nozzle openings 11a (on one nozzle opening side), is welded to the nozzle opening body 11. A cylindrical end section of the main body 12 on a side facing away from the nozzle openings 11a (on a side opposite the nozzle openings) is welded to a cylindrical end section of the non-magnetic element 14. A cylindrical end section of the non-magnetic element 14 on the side opposite the nozzle opening is welded to the solid core 13.

[0027] A nut element 15 is attached to a threaded section 13N of the solid core 13 in a state where it is locked to a locking section 12c of the main body 12. An axial force generated by the attachment produces a surface pressure that pulls the nut element 15, the main body 12, the non-magnetic element 14, and the solid core 13 in the direction of the axis line C (in the vertical direction). Fig. 1) presses against each other. Instead of creating such surface pressure by means of fastening screws, the surface pressure can also be created by pressing in or press fit.

[0028] The main body 12 is made of a magnetic material such as stainless steel and has a flow channel 12b to allow the fuel to flow into the nozzle openings 11a inside. The needle 20 is movably mounted in the flow channel 12b in the direction of the axis C. The main body 12 and the non-magnetic element 14 form a "holder" with a movable chamber 12a filled with fuel. A movable section M (see Fig. 9 and Fig. 10), which is an assembly or structure in which the needle 20, the movable core 30, the second spring element SP2, the sleeve 40 and the cup 50 are joined together, is movably housed in the movable chamber 12a. A in Fig. The gap L1a shown in Figure 9 indicates the size of a gap between a valve closing contact surface 21b and a valve closing force transmission contact surface 52c in the direction of the axis line C. The size of the gap L1a corresponds to the size of a gap L1 that is located in a column (a) of Fig. 4 is shown.

[0029] The flow channel 12b is shaped such that it communicates with a downstream side of the movable chamber 12a and extends in the direction of axis C. A center line of the flow channel 12b and the movable chamber 12a coincides with a cylindrical center line (axis C) of the main body 12. A nozzle-opening-side section of the needle 20 is slidably supported by an inner wall surface 11c of the nozzle opening body 11, and a section of the needle 20 on a side opposite the nozzle openings is slidably supported by an inner wall surface 51b of the cup 50 (see Fig. 8 and Fig. 12) Two positions of an upstream end section and a downstream end section of the needle 20 are slidably mounted in this way, thereby limiting the movement of the needle 20 in the radial direction and limiting the inclination of the needle 20 relative to the axis line C of the main body 12.

[0030] The needle 20 corresponds to a "valve body" that opens and closes the nozzle openings 11a and is made of a magnetic material such as stainless steel, with a shape extending along the axis C. The valve body-side seat 20s described above is formed on a downstream end face of the needle 20. When the needle 20 moves downstream along the axis C (valve closing operation), the valve body-side seat 20s engages the housing-side seat 11s to close the flow channel 11b and the nozzle openings 11a. When the needle 20 moves upstream along the axis C (valve opening operation), the valve body-side seat 20s disengages from the housing-side seat 11s to open the flow channel 11b and the nozzle openings 11a.

[0031] The needle 20 has an inner passage 20a and side openings 20b so that the fuel can flow through the nozzle openings 11a (see Fig. 3) The multiple lateral openings 20b are provided circumferentially. The multiple lateral openings 20b are provided at regular intervals circumferentially. The inner passage 20a has a shape that extends in the direction of the axis C of the needle 20. An inlet port is provided at an upstream end of the internal passage 20a, and the lateral openings or holes 20b are connected to a downstream end of the internal passage 20a. The lateral openings 20b extend in a direction that intersects the direction of the axis C and are connected to the movable chamber 12a.

[0032] As in Fig. As shown in Figure 7, the needle 20 has a contact section 21, a core sliding section 22, a press-fit section 23, an outlet section 24, a first large-diameter section 25, a first small-diameter section 26, a second large-diameter section 27, a second small-diameter section 28, and a nozzle-opening-side bearing section 29 in a specified order from the opposite side (upper end) to the lower end of the valve body-side seat 20s. The contact section 21 has the valve closing contact surface 21b, which contacts the contact surface 52c of the cup 50 to transmit the valve closing force.

[0033] The cup 50 is slidably assembled with the contact section 21, and an outer circumferential surface of the contact section 21 slides with an inner circumferential surface of the cup 50. The movable core 30 is slidably connected to the core sliding section 22, and an outer circumferential surface of the core sliding section 22 slides with an inner circumferential surface of the movable core 30. A sleeve 40 is pressed or press-fitted into the press-fit section 23. The lateral openings 20b are provided in the outlet section 24.

[0034] The outer diameter D1 of the contact section 21 is larger than the outer diameter D2 of the core sliding section 22, the outer diameter D2 of the core sliding section 22 is larger than the outer diameter D3 of the press-fit section 23, and the outer diameter D3 of the press-fit section 23 is larger than the outer diameter of the outlet section 24. A connecting part 22a between the core sliding section 22 and the press-fit section 23, and a connecting part 23a between the press-fit section 23 and the outlet section 24, are each inclined. The diameter of an inner circumferential surface 41a of the sleeve 40 in a state prior to pressing or press-fitting is adjusted so that it is smaller than the outer diameter D3 of the press-fit section 23, and the pressing or press-fitting can then be carried out.

[0035] The outer diameters of the first large-diameter section 25 and the second large-diameter section 27 are larger than the outer diameters of the first small-diameter section 26 and the second small-diameter section 28. The weight reduction is achieved through the first small-diameter section 26 and the second small-diameter section 28. The first large-diameter section 25 and the second large-diameter section 27 serve as bearing and support sections, respectively, when the needle 20 is cut. The second small-diameter section 28 acts as an outlet section, ensuring that a cutting tool does not obstruct the cutting of the nozzle-opening-side bearing section 29. The nozzle-opening-side bearing section 29 is slidably supported by the inner wall surface 11c of the nozzle opening body 11.

[0036] The cup 50 has a circular cup section 52 with a circular plate shape and a cylindrical section 51 with a cylindrical shape. The circular plate section 52 has a through-opening 52a extending in the direction of the axis line C. A surface of the circular plate section 52 on a side opposite the nozzle openings acts as a spring contact surface 52b, which contacts the first spring element SP1. A surface of the circular plate section 52 on the side of the nozzle opening acts as a contact surface 52c for transmitting the valve closing force, which contacts the needle 20 and transmits a first elastic force (an elastic force for closing the valve, or an elastic valve closing force). The circular plate section 52 corresponds to a "valve body transmission section" that contacts the first spring element SP1 and the needle 20 to transmit the first elastic force to the needle 20.The cylindrical section 51 has a cylindrical shape extending from an outer circumferential end of the circular plate section 52 towards the nozzle opening side. A nozzle opening-side end surface of the cylindrical section 51 acts as a core contact end surface 51a, which contacts the movable core 30. The inner wall surface 51b of the cylindrical section 51 slides with the outer circumferential surface of the contact section 21 of the needle 20.

[0037] The solid core 13 is made of a magnetic material such as stainless steel and has a flow channel 13a to allow the fuel to flow through the nozzle openings 11a. The flow channel 13a communicates with the inner passage 20a, which is located inside the needle 20 (see Fig. 3) and an upstream side of the movable chamber 12a, and extends in the direction of the axis line C. The flow channel 13a accommodates the guide element 60, the first spring element SP1 and the support element 18.

[0038] The support element 18 has a cylindrical shape and is press-fitted into an inner wall surface of the solid core 13. The first spring element SP1 is a coil spring located on the downstream side of the support element 18 and deforms elastically in the direction of the axis C. An upstream end face of the first spring element SP1 is supported by the support element 18, and a downstream end face of the first spring element SP1 is supported by the cup 50. A force generated by the elastic deformation of the first spring element SP1 (a first elastic force) pushes the cup 50 towards the downstream side. The degree of the press fit of the support element 18 in the direction of the axis C is adjusted to set a specific elastic force acting on the cup 50 (a first set load).

[0039] As in Fig. As shown in Figure 3, the guide element 60 has a cylindrical shape made of a magnetic material such as stainless steel and is press-fitted into an enlarged-diameter section 13c formed in the solid core 13. The enlarged-diameter section 13c has a shape in which the flow channel 13a is enlarged in the radial direction. The guide element 60 has a circular plate section 62 and a cylindrical section 61. The circular plate section 62 has a through-opening 62a extending along the axis C. A surface of the circular plate section 62 on the side opposite the nozzle openings contacts an inner wall surface of the enlarged-diameter section 13c. The cylindrical section 61 has a cylindrical shape extending from the outer circumferential end of the circular plate section 62 to the side of the nozzle opening.A nozzle-opening end surface of the cylindrical section 61 acts as a stopper contact end surface 61a, which contacts the movable core 30. An inner wall surface of the cylindrical section 51 forms a sliding surface 61b, which slides with an outer circumferential surface 51d of the cylindrical part 51 of the cup 50 (see . Fig. 12).

[0040] In short, the guide element 60 has a guiding function, whereby the outer circumferential surface of the cup 50 slides in the direction of the axis line C, and a stopping function, whereby the movable core 30, which moves in the direction of the axis line C, is touched and the movable core 30 is prevented from moving to the side opposite the nozzle openings. In other words, the guide element 60 corresponds to a “stopper element” that touches the movable core 30 and prevents the movable core 30 from moving away from the nozzle openings 11a.

[0041] A resin element 16 is provided on an outer circumferential surface of the solid core 13. The resin element 16 has a connector housing 16a, and a terminal 16b is housed in the connector housing 16a. The terminal 16b is electrically connected to the coil 17. An external connector (not shown) is connected to the connector housing 16a, and the coil 17 is supplied with electrical energy via the terminal 16b. The coil 17 is wound around a coil former 17a, which has electrical insulating properties, thus forming a cylindrical shape, and is located on a radially outer side of the solid core 13, the non-magnetic element 14, and the movable core 30. The solid core 13, the mother element 15, the main body 12, and the movable core 30 form a magnetic circuit to conduct a magnetic flux generated by a power supply (excitation) to the coil 17 (see dashed arrow in Figure 1). Fig. 3).

[0042] As in Fig. As shown in Figure 3, the movable core 30 is arranged on the nozzle opening side with respect to the fixed core 13 and is housed in the movable chamber 12a in a state movable in the direction of the axis line C. The movable core 30 has an outer core 31 and an inner core 32. The outer core 31 has a cylindrical shape made of a magnetic material such as stainless steel, and the inner core 32 has a cylindrical shape made of a non-magnetic material such as stainless steel that possesses magnetic properties. The outer core 31 is pressed into an outer circumferential surface of the inner core 32.

[0043] The needle 20 is inserted into a cylindrical inner section of the inner core 32. The inner core 32 is mounted to the needle 20 such that it is displaceable relative to the needle 20 along axis C. A gap (inner gap) between an inner circumferential surface of the inner core 32 and an outer circumferential surface of the needle 20 is adjusted to be smaller than a gap (outer gap) between an outer circumferential surface of the outer core 31 and an inner circumferential surface of the main body 12. These gaps are adjusted such that the outer core 31 does not touch the main body 12, while the inner core 32 touches the needle 20.

[0044] The inner core 32 contacts the guide element 60 as a stop element, the cup 50, and the needle 20. For this reason, a material with a higher degree of hardness than that of the outer core 31 is used for the inner core 32. The outer core 31 has a movable core surface 31c opposite or facing the fixed core 13, and a gap is provided between the movable core surface 31c and the fixed core 13. Therefore, in a state where a magnetic flux flows due to excitation of the coil 17 as described above, a magnetic attraction force, attracted by the fixed core 13, acts on the outer core 31 by virtue of the gap.

[0045] The sleeve 40 corresponds to a "solid element" that is pressed into or press-fitted into the needle 20. The sleeve 40 consists of a cylindrical metal part with a through-bore or through-opening 40a (see Fig. 7) and comprises a cylindrical insertion section 41, a connecting section 42, and a bearing section 43. The cylindrical insertion section 41 has a cylindrical shape and is press-fitted into the press-fit section 23 of the needle 20. The connecting section 42 has a cylindrical shape, in which the cylindrical insertion section 41 is enlarged in the radial direction, and connects the cylindrical insertion section 41 and the bearing section 43. The connecting section 42 guides the second spring element SP2 to reduce any positional deviation of the second spring element SP2 in the radial direction. The bearing section 43 has an annular flange shape that extends from the nozzle-opening-side end section of the connecting section 42 to the radially outer side.In other words, the bearing section 43 has a plate shape extending from the nozzle-opening end section of the connecting section 42 to the radially outer side, and a ring shape extending around the axis line C. A surface of the bearing section 43 on the side opposite the nozzle opening acts as a support surface 43a for supporting the nozzle-opening end surface of the second spring element SP2.

[0046] The second spring element SP2 is a coil spring located on the side opposite the nozzle openings with respect to the bearing section 43 and is elastically deformed in the direction of the axis C. An end face of the second spring element SP2 on the side opposite the nozzle opening is supported by the movable core 30, more precisely by the outer core 31. A nozzle-opening-side end face of the second spring element SP2 is supported by the bearing section 43. The force generated by the elastic deformation of the second spring element SP2 (the second elastic force) pushes the outer core 31 in the direction opposite the nozzle openings. By adjusting the degree of interference fit of the cylindrical insertion section 41 in the direction of the axis C, the magnitude of the second elastic force for pushing the movable core 30 (a second adjustable load) at the time of valve closure is set.The second adjustable load, based on the second spring element SP2, is smaller than the first adjustable load, based on the first spring element SP1. Furthermore, the magnitude of the second elastic force can be adjusted as the second adjustable load not only when the valve is closed, but also when the movable core 30 is compressed in another situation, by adjusting the degree of press fit. <Beschreibung des Vorgangs bzw. des Betriebs>

[0047] Next, the operation of fuel injector 1 will be explained using the Fig. 4 and Fig. 5 described.

[0048] As in a column (a) of Fig. As shown in Figure 4, in a state where the coil 17 is de-energized, no magnetic attraction force is generated, so that the magnetic attraction force driven towards the valve opening side does not act on the movable core 30. The cup 50, which is pressed towards the valve closing side by the first elastic force generated by the first spring element SP1, contacts the valve closing contact surface 21b of the needle 20 (see Figure 4). Fig. 3) and the inner cores 32 to transmit the first elastic force.

[0049] The movable core 30 is forced towards the valve closing side by the first elastic force of the first spring element SP1, transmitted by the cup 50, and the movable core 30 is forced towards the valve opening side by the second elastic force of the second spring element SP2. Since the first elastic force is greater than the second elastic force, the movable core 30 is pushed through the cup 50 and moved towards the nozzle openings (lifted downwards). The needle 20 is forced towards the valve closing side by the first elastic force transmitted by the cup 50 and pushed through the cup 50 towards the nozzle opening side (lifted downwards), i.e., placed on the housing-side seat 11s to close the valve. In the closed state of the valve, a gap exists between the valve opening contact surface 21a (see Fig. 3) the needle 20 and the movable core 30 (the inner core 32) are provided, and the length of the gap in the direction of the axis line C in the closed state of the valve is referred to as the gap L1.

[0050] As in a column (b) of Fig. As shown in Figure 4, in the state immediately after the excitation of coil 17 switches from OFF to ON, the magnetic attraction force pressed towards the valve opening side acts on the movable core 30, and the movable core 30 begins to move towards the valve opening side. When the movable core 30 then moves while the cup 50 is pushed upwards, and the amount of movement reaches the gap L1, the inner core 32 collides with the valve opening contact surface 21a of the needle 20. At the time of the collision, a gap is provided between the guide element 60 and the inner core 32, and the length of the gap in the direction of the axis line C is referred to as the stroke L2.

[0051] Since the elastic force of the first spring element SP1 only acts on the needle 20 at the moment of collision, the collision speed of the movable core 30 can be increased accordingly. Because such a collision force is added to the magnetic attraction force and used as the valve opening force of the needle 20, the needle 20 can be actuated in such a way that the valve is opened even with high-pressure fuel, thereby preventing an increase in the magnetic attraction force required to open the valve. The elastic force of the first spring element SP1 acts on the needle 20 towards the valve closing side in the state shown in column (a), but does not act on the needle 20 in the state shown in column (b). For this reason, the inhibition of the increase in the magnetic attraction force required to open the valve can be further promoted.

[0052] After the collision, the movable core 30 continues to move due to the magnetic attraction, and when the amount of movement after the collision reaches the elevator L2, the inner core 32 collides with the guide element 60 and stops the movement, as shown in column (c) of Fig. Figure 4 shows a separation distance between the housing-side seat 11s and the valve body-side seat 20s in the direction of the axis line C at the time the movement stops corresponds to a full stroke of the needle 20 and corresponds to the stroke L2 described above.

[0053] If the above-described process refers to Fig. 5, as described in detail, begins when the excitation is switched on at time t1, as shown in column (a) of Fig. As shown in Figure 5, a drive current flowing through coil 17 increases (see column (b)), and the magnetic attraction force begins to increase with the increase in drive current (see column (c)). If a value obtained by subtracting the second elastic force from the first elastic force (elastic valve closing force) is defined as the actual valve closing elasticity F0, the movable core 30 begins to move towards the valve opening side at time t2 when the magnetic attraction force increases to the actual valve closing elasticity F0. Before the drive current reaches a peak value, the movable core 30 begins to move. A boost voltage obtained by increasing a battery voltage is applied to coil 17 until the drive current reaches the peak value, and the battery voltage is applied to coil 17 after the drive current has reached the peak value.

[0054] Then, at time t3, when the movement of the movable core 30 reaches the gap L1, the movable core 30 collides with the needle 20, and the needle 20 begins the valve opening process (see column (d)). As a result, fuel is injected from the nozzle openings 11a. Subsequently, the movable core 30 lifts the needle 20 against the elastic closing force of the valve, and at time t4, when the movable core 30 collides with the guide element 60, the stroke of the needle 20 reaches its full stroke (stroke L2). A zero point shown on a vertical axis of column (d) indicates a collision position between the movable core 30 and the needle 20 at time t3.

[0055] The magnetic attraction then maintains a full stroke of the needle 20, and fuel injection continues. Subsequently, when the excitation is switched off at time t5, the magnetic attraction also decreases with a decrease in the drive current. At time t6, when the magnetic attraction reaches the actual valve closing elastic force, or the elastic valve closing force F0, the movable core 30 begins to move towards the valve closing side together with the cup 50. The needle 20 is pushed by the pressure of the fuel injected between the needle 20 and the cup 50 to initiate the downward movement (the valve closing process) simultaneously with the start of the movement of the movable core 30.

[0056] Then, at time t7, when the needle 20 is lifted downwards by the stroke L2, the valve body-side seat 20s rests on the housing-side seat 11s to close the flow channel 11b and the nozzle openings 11a. The movable core 30 then moves further towards the valve closing side together with the cup 50, and the movement of the cup 50 towards the valve closing side is stopped at time t8 when the cup 50 contacts the needle 20. Afterwards, the movable core 30 continues to move towards the valve closing side due to an inertial force (inertial motion), and then the movable core 30 moves towards the valve opening side due to the elastic force of the second spring element SP2 (rebound).Then the movable core 30 collides with the cup 50 at time t9 and moves together with the cup 50 towards the valve opening side (rebounds), but is quickly pushed back by the elastic closing force of the valve and converges to an initial state which is in the column (a) of . Fig. 4 is shown.

[0057] The smaller the rebound and the shorter the time required for convergence, the shorter the time from the end of the injection until the return to the initial state. For this reason, in multi-stage injection, where fuel is injected several times per combustion cycle of the internal combustion engine, the interval between injections can be shortened and the number of injections included in the multi-stage injection can be increased. Furthermore, by shortening the convergence time as described above, the injection quantity can be controlled with high accuracy when performing partial-stroke injection, as described below. In partial-stroke injection, a small quantity is injected due to a short valve opening time. This occurs when the excitation of coil 17 is stopped and the valve closing process is initiated before the needle 20, which performs the valve opening process, reaches the full-stroke position. <Beschreibung des Herstellungsverfahrens>

[0058] Next, a method for manufacturing the fuel injection valve 1 is described.

[0059] This manufacturing process includes the initial adjustment of the adjusting load, the process for assembling the moving section, the welding process, the fastening process, and the resin molding process described below.

[0060] In a manufacturing process for the movable section, the movable core 30, the second spring element SP2, the sleeve 40, and the cup 50 with the needle 20 are assembled to produce the movable part M. As will be described in detail later, the movable part M is manufactured such that the elastic force exerted on the second spring element SP2 by the movable core 30 becomes a setpoint value for the second adjustable load.

[0061] In the next welding process, the nozzle opening body 11 is first welded and connected to the main body 12. Next, the movable section M is positioned in the movable chamber 12a of the main body 12, and then the fixed core 13, on which the support element 18 and the first spring element SP1 are mounted, the main body 12, on which the movable section M is positioned, and the non-magnetic element 14 are welded and coupled together.

[0062] In the next fastening process, the coil 17a or the coil carrier 17a, in a state where the coil 17 is wound, is positioned between the mother element 15 and the solid core 13. The mother element 15 is then attached to the solid core 13, so that the main body 12, the non-magnetic element 14, and the solid core 13 are joined together by generating surface pressure.

[0063] In the next resin molding process, the resin element 16 with the connector housing 16a is cast in resin by pouring and solidifying molten resin onto the outer circumferential surface of the solid core 13.

[0064] In the subsequent initial adjustment process for the adjustment load, the first spring element SP1 is first mounted onto the flow channel 13a of the solid core 13. Then, the support element 18 is press-fitted into the flow channel 13a of the solid core 13 to a predetermined position. The predetermined position of the press fit can be determined in accordance with the variations in the elastic modulus of the first spring element SP1 and its length along the axis C, as well as the variations in the dimensions of the respective sections of the solid core 13. In any case, the predetermined position (press-in position or press-fit position) is set such that the first elastic force exerted by the needle 20 becomes a target value of the first adjustment load. The fuel injector 1 is manufactured according to the manufacturing process, including the aforementioned operations. <Detaillierte Beschreibung der Konfigurationsgruppe A>

[0065] Next, among the configurations of the fuel injection valve 1 according to the present embodiment, a configuration group A, which includes at least the press-fit section 23 formed on the needle 20 and the configuration associated with the press-fit section 23, is described in detail.

[0066] The assembly of the movable section described above includes the parts shown in Fig. 6 detailed steps S10 to S15. First, in step S10, as in Fig. As shown in Figure 7, the movable core 30, the second spring element SP2, and the sleeve 40 are inserted into the needle 20s from the side (the lower end) of the valve body seat 20s. In this step S10, as shown in Fig. Figure 8 shows the insertion of the sleeve 40 stopped at a position of the outflow section 24 before the press-fit section 23.

[0067] In the subsequent step S11, the needle 20 is pressed against the cup 50 in a state in which the cup 50 is assembled with the contact section 21 of the needle 20 and the contact surface 52c touches the valve closing contact surface 21b to transmit the valve closing force (see Fig. 8) As a result, the core contact end surface 51a is positioned closer to the nozzle opening than the valve opening contact surface 21a by the amount corresponding to the gap L1.

[0068] In the subsequent step S12, the sleeve 40 is temporarily press-fitted into the press fit section 23 with a predetermined degree of press fit. For example, while the cup 50 is supported in the direction of the axis C using a support device J1, the press fit load F2 is applied to the load application surface 43b of the sleeve 40 in the direction of the axis C using the load application device J2. During a temporary press fit, the movable core 30 contacts the cup 50, the second spring element SP2 contacts the sleeve 40 and the movable core 30, and the second spring element SP2 is in an elastically deformed state. Therefore, the support device J1 has a reaction force F1 against the second elastic force exerted by the second spring element SP2 to support the cup 50.

[0069] The temporary press fit is a first press fit, and afterwards a second press fit (main press fit) is performed in step S15 (described later). The degree of the press fit in the temporary press fit is a predetermined amount, independent of any variation in machine differences, and the temporary press fit is performed, for example, at a location separated from the nozzle-opening end section of the press fit section 23 by a predetermined length in the direction of axis C towards the side opposite the nozzle openings.

[0070] In the subsequent step S13, the second elastic force exerted by the second spring element SP2, i.e., the second set load, is measured. For example, a force (reaction force F1) by which the support device J1 is pressed by the second elastic force is measured using a measuring device (not shown). In this step S13, the measurement is performed in a state where the cup 50 is positioned above the needle 20, i.e., in a state where the direction of the movable section M is set in the direction of an arrow indicating the vertical direction. Fig. 8 is displayed.

[0071] In the subsequent step S14, the shortfall of the measured second settling load compared to a second target settling load is calculated, and an additional degree of interference fit is calculated accordingly. For example, the modulus of elasticity of the second spring element SP2 can be measured in advance, and the additional degree of interference fit can be calculated based on the measured shortfall and the modulus of elasticity. Alternatively, the modulus of elasticity of the second spring element SP2 can be considered a standard value, and the additional degree of interference fit can be calculated based on the measured shortfall and the standard value.

[0072] In the subsequent step S15, the sleeve 40 is further press-fitted into the press-fit section 23 with the additional press-fit tolerance calculated in step S14 (main press fit). As described above, the assembly of the movable section M is complete. In short, the second setting load is measured during the press-fitting process, and a main press fit is performed according to the measured value. Each step described above is an example for configuration group A described above.

[0073] As described above, the fuel injection valve 1, according to the present embodiment, comprises the needle 20 (valve body), the fixed core 13, the movable core 30, the first spring element SP1, the sleeve 40 (fixed element), and the second spring element SP2. The movable core 30 contacts the needle 20 at the point when the movable core 30 is attracted by the fixed core 13 and moved by a predetermined amount to the side opposite the nozzle openings, thus opening the needle 20. The first spring element SP1 is elastically deformed during the opening process of the needle 20 and exerts the first elastic force to close the needle 20. The sleeve 40 is attached to the needle 20. The second spring element SP2 is clamped between the sleeve 40 and the movable core 30 and is elastically deformed, exerting the second elastic force to push the movable core 30 to the side opposite the nozzle opening.The needle 20 has the press-fit section 23, into which the sleeve 40 is press-fitted on the side opposite the nozzle openings, and the sleeve 40 is attached to the needle 20 by press-fitting into the press-fit section 23.

[0074] In short, according to the present embodiment, the fuel injector 1 has a core-boost structure in which the fuel injector 1 contacts the needle 20 at the moment when the movable core 30 is moved laterally by a predetermined distance relative to the nozzle openings to open the fuel injector 1. The sleeve 40 supports the second spring element SP2, which pushes the movable core 30 laterally relative to the nozzle openings. The sleeve 40 is attached to the needle 20 by press-fitting, and the press-fit direction of the sleeve 40 is the same as the press-fit direction of the second spring element SP2. This makes it possible to adjust and fix the degree of press fit and simultaneously measure the second elastic force, which increases with the progress of the press fit.Therefore, the second elastic force can be set with high accuracy to the target set load of the second spring element SP2 at the time of completion of the press fit.

[0075] The set load is a second elastic force exerted by the elastic deformation of the second spring element when it is assembled with the fuel injector. Since the magnitude of the set load influences the valve body's opening and closing timing, adjusting the set load to the target value with high accuracy contributes to reducing the variation in the fuel injection quantity. Unlike the current embodiment, where the fixed element is press-fitted into the valve body, in a design where the fixed element is welded and attached to the valve body, the welded section cannot be adjusted during the measurement of the second elastic force. Therefore, the set load varies due to differences between individuals, such as...Fluctuations in the machine difference of the second spring element and fluctuations in the valve body length, as well as due to the thermal stress from welding.

[0076] On the other hand, in the present embodiment, since the fixed element is press-fitted into the valve body, the set load can be adjusted to the target value with high accuracy, as described above. This makes it possible to reduce the variation in the fuel injection quantity while simultaneously retaining the core boost structure.

[0077] Furthermore, in the fuel injection valve 1 according to the present embodiment, at least one section of the sleeve 40, which is in contact with the press-fit section 23, has a different hardness than the press-fit section 23. For example, metal base materials with different hardnesses can be used for the sleeve 40 and the needle 20, or a surface treatment such as a heat treatment can be carried out on the metal base material of the sleeve 40 to make a section of the sleeve 40, which is in contact with the press-fit section 23, locally harder than the sleeve 40.

[0078] In contrast to the present embodiment, where the sleeve 40 and the press fit section 23 have the same hardness, there is a concern that the sleeve 40 and the press fit section 23 will adhere to each other if the press fit process is temporarily stopped during measurement while adjusting the press fit. If adhesion occurs, the stress required to resume the press fit increases, and the workability of the press fit deteriorates. Therefore, according to the present embodiment with the different hardness, the aforementioned adhesion problem can be reduced, and the workability of the press fit can be improved. The needle 20 is preferably harder than the sleeve 40. The sleeve 40 preferably has a higher hardness than that of the movable core 30. A specific example of the material for the needle 20 is martensitic stainless steel.A specific example of the material used for sleeve 40 is ferritic stainless steel.

[0079] Furthermore, in the fuel injection valve 1 according to the present embodiment, at least one section of the sleeve 40, which is in contact with the press-fit section 23, has a lower hardness than the press-fit section 23.

[0080] In an interference fit, at least one of the two elements to be pressed in must be plastically deformed. Since the hardness is lower, the element can be plastically deformed more easily, and the interference fit load required for pressing in or the interference fit can be reduced. Because the needle 20 requires a (high) hardness to withstand the collision with the housing-side seat 11s (valve seat), there is a concern that the force required for the interference fit or the interference fit load will increase if the sleeve 40 is harder than the needle 20 to create a hardness difference. Therefore, according to the present embodiment, in which the sleeve 40 has a lower hardness than the interference fit section 23, the aforementioned concern regarding the improvement of interference fit processability can be mitigated.Since the sleeve 40 does not come into contact with the movable core 30 according to the present embodiment, a material can be used that is softer than that of the inner core 32 or similar material that requires contact.

[0081] For example, the solid lines A1 and A2 show in Fig. 11 The stress-strain-L diagrams of needle 20 and sleeve 40, obtained from a tensile test, are shown. As the test results indicate, the stress at the yield strength (yield stress σ1), at which sleeve 40 begins plastic deformation, is lower than that of needle 20. In the case of needle 20, a test specimen broke as soon as the yield stress was reached. The test results show that the yield stress σ1 can be reduced by increasing the hardness of sleeve 40 and decreasing the press fit load required for the press fit.

[0082] Furthermore, in the fuel injection valve 1 according to the present embodiment, the sleeve 40 and the movable core 30 are separated from each other without touching each other, even when the movable core 30 is moved to its maximum relative movement towards the nozzle openings with respect to the needle 20. For example, after the valve closes, the movable core 30 continues to move towards the nozzle opening side, and the recoil occurs as described above. A condition in which the further movement of the movable core 30 occurs after the valve closes and the interval between the lines of the second spring element SP2 becomes zero, so that the elastic deformation of the second spring element SP2 is maximized, is illustrated as a specific example of a case in which the relative movement is maximized.

[0083] In contrast to the present embodiment, a structure in which the sleeve 40 and the movable core 30 are in contact with each other requires a large clearance for the press fit and increases the plastic deformation caused by the press fit, since it is necessary to reinforce the press fit of the sleeve 40. Therefore, according to the present embodiment of the structure in which the sleeve 40 and the movable core 30 do not contact each other, the need for reinforcing the press fit can be reduced, thus reducing the press fit load required for the press fit and improving the machinability of the press fit.

[0084] Furthermore, in the fuel injection valve 1 according to the present embodiment, the sleeve 40 has the cylindrical insertion section 41 with a cylindrical shape, which is inserted into the press fit section 23, and the inner circumferential surface 41a of the cylindrical insertion section 41 is press-fitted into the outer circumferential surface of the press fit section 23 over its entire circumference. Since the internal stress generated in the cylindrical insertion section 41 can be distributed over its entire circumference, damage to the sleeve 40 can be reduced by the concentration of the internal stress according to the configuration described above.

[0085] In the method for manufacturing the fuel injection valve 1 according to the present embodiment, the fuel injection valve 1 is to be manufactured with the following structure. In other words, the needle 20 (valve body), which opens and closes the nozzle openings 11a for injecting the fuel, is actuated to close the valve by the first elastic force, which is generated by the first elastically deformed and flared spring element SP1, and to open the valve by the movable core 30, which is moved by the magnetic attraction force. Additionally, the movable core 30 is forced to the side opposite the nozzle openings by the second elastic force, which is generated by the second spring element SP2. This spring element is elastically deformed by being clamped between the sleeve 40 (fixed element) attached to the needle 20 and the movable core 30.The manufacturing process described above comprises steps S12 and S15 (press-fit procedure and press-fit procedure, respectively) of press-fitting the sleeve 40 (fixed element) into the press-fit section 23 of the needle 20. This press-fits the sleeve 40 into the press-fit section 23 formed in the needle 20, which contacts the movable core 30 and initiates the valve opening process when the movable core 30 is moved by a predetermined amount by the magnetic attraction force. Furthermore, the manufacturing process described above includes step S13 (the load measurement procedure) of measuring the second elastic force in a state where the movable core 30 is immobilized during the press-fit process. In the press-fit procedure, the degree of press fit is adjusted based on the measurement result to complete the press fit.

[0086] In short, in the manufacturing process according to the present embodiment, the fuel injection valve 1 is to be manufactured with the core reinforcement structure comprising the sleeve 40, which carries the second spring element SP2 to push the movable core 30 towards the side opposite the nozzle openings. While the sleeve 40 is being press-fitted into the press fit section 23 of the needle 20, the second elastic force is measured while the movable core 30 remains stationary, and the degree of press fit is adjusted based on the measurement result to complete the press fit. Therefore, the second elastic force can be set with high accuracy to the target set load of the second spring element SP2 at the time of completion of the press fit.

[0087] Since, as described above, the magnitude of the set load influences the valve opening and closing timing of needle 20, adjusting the set load to the target value with high accuracy contributes to reducing variation in the fuel injection quantity. Therefore, according to the present embodiment, in which the set load can be adjusted to the target value with high accuracy as described above, the fluctuation in the fuel injection quantity can be reduced using the core boost structure.

[0088] Furthermore, in the manufacturing process according to the present embodiment, the next fuel injector 1 is to be manufactured. The fuel injector 1 is arranged so that it is movable relative to the needle 20 and comprises the cup 50, which contacts the needle 20 by moving relative to the fuel nozzle openings and transmitting the first elastic force from the first spring element SP1 to the needle 20. In the manufacturing process described above, in step S13 (load measurement process), the cup 50 is moved relative to the needle 20, and the cup 50, in the contacting state, is brought into contact with the movable core 30, thereby regulating the movement of the movable core 30.

[0089] The magnitude of the second settling load applied by the second spring element SP2 is important to prevent the movable core 30 from moving towards the nozzle opening after the valve closes; that is, this is crucial for rapid rebound convergence. Therefore, setting the second elastic force in the closed state as the second settling load, or adjustment load, is advantageous for managing rebound convergence. Since the second elastic force is measured by regulating the movement of the movable core 30 through contact with the cup 50, which touches the needle 20, the second elastic force is measured in the closed state of the valve. This allows for easy management of rebound convergence. <Detaillierte Beschreibung der Konfigurationsgruppe B>

[0090] Next, among the configurations of the fuel injector 1 according to the present embodiment, a configuration group B is defined, comprising at least the fuel storage chamber B1, which is described below, and the configuration relating to the fuel reservoir B1, with reference to the Fig. Sections 12 to 14 are described in detail. Furthermore, a modification of configuration group B will be described later with reference to the Fig. Described in sections 15 to 23.

[0091] As in Fig. As shown in Figure 12, the fuel storage chamber B1 is a section in which the fuel is accumulated in a state where it is surrounded by the movable core 30, the cup 50, and the needle 20. In the following description, a surface of the inner core 32 on the side opposite the nozzle opening, which contacts the needle 20, is referred to as the first core contact surface 32c, a surface of the inner core 32 which contacts the cup 50 is referred to as the second core contact surface 32b, and a surface of the inner core 32 which contacts the guide element 60 is referred to as the third core contact surface 32d.

[0092] Since the movable core 30 is pressed against the cup 50 by the second elastic force, the movable core 30 is always in contact with the cup 50, except when, after the valve closes, the movable core 30 moves inertly and separates from the cup 50. More precisely, the second core contact surface 32b of the inner core 32 is always in contact with the core contact end surface 51a of the cup 50. The cylindrical section 51 of the cup 50, which forms the core contact end surface 51a, separates the inner and outer sides of the fuel storage chamber B1. The outer side is the area where the fuel is present radially outside the outer circumferential surface 51d of the cup 50, the first core contact surface 32c is located inside the fuel storage chamber B1, and the third core contact surface 32d is located outside the fuel storage chamber B1.

[0093] The fuel storage chamber B1 is a region enclosed by the outer circumferential surface of the core sliding section 22 of the needle 20, the valve opening contact surface 21a, the inner wall surface of the through-hole 32a of the inner core 32, the first core contact surface 32c, and the inner circumferential surface of the cylindrical section 51 of the cup 50. The fuel storage chamber B1 is a region enclosed as described above in a state where the movable core 30 and the cup 50 are in contact with each other. The fuel storage chamber B1 is a region enclosed as described above in a state where the valve body-side valve seat 20s is in contact with the body-side seat 11s and the needle 20 is closed.

[0094] Communication grooves 32e are provided in the first core contact surface 32c and the second core contact surface 32b of the inner core 32. The communication grooves 32e connect the interior and exterior of the fuel storage chamber B1 in a state where the second core contact surface 32b touches the core contact end surface 51a. The exterior is a different space than the fuel storage chamber B1 when the cup 50 and the movable core 30 are in contact.

[0095] Here, the outer surface of the fuel storage chamber B1 corresponds to a region, which is illustrated below as an example. In other words, a first region between the stopper contact end surface 61a and the third core contact surface 32d of the guide element 60 corresponds to an outer surface. The first region is a region formed in a state where the cup 50 and the movable core 30 are in contact with each other, and the movable core 30 and the guide element 60 are not in contact with each other. A surface of the fixed core 13 facing the movable core 30 is referred to as the fixed side surface of the core 13b. A surface of the outer core 31 facing the fixed core 13 is referred to as the movable core surface 31c. A second region between the surface 13b facing the fixed core and the surface 31c facing the movable core, which is connected to the first region, corresponds to the outer surface.A third area, which is connected to the second area, between the inner circumferential surfaces of the main body 12 (holder) and the non-magnetic element 14 (holder) and the outer circumferential surface of the outer core 31 corresponds to the outside.

[0096] As in Fig. As shown in Figure 13, multiple (e.g., four) communication grooves 32e are provided, and these multiple communication grooves 32e are arranged at regular intervals in the circumferential direction, as seen from the direction of movement of the movable core 30. Each communication groove 32e has a shape extending linearly in the radial direction. Each of the multiple communication grooves 32e has the same shape. The circumferential positions of the communication grooves 32e differ from the circumferential positions of the through-openings 31a.

[0097] The inner core 32 corresponds to a "contact section" in which the first core contact surface 32c and the second core contact surface 32b are formed. The outer core 31 corresponds to a "core body section" made of a different material than the inner core 32, on which the movable core surface 31c facing the fixed core 13 is formed. The core body section lies outside the area in which the communication grooves 32e extend. In other words, the communication grooves 32e are provided in the inner core 32, but not in the outer core 31.

[0098] The communication grooves 32e are provided over the entire surface in the radial direction of the inner core 32 and extend from the inner circumferential surface to the outer circumferential surface of the inner core 32. In other words, the communication grooves 32e are provided over the entire surface in the radial direction of the first core contact surface 32c, the second core contact surface 32b, and the third core contact surface 32d.

[0099] As in Fig. As shown in Figure 14, the communication grooves 32e each have a bottom wall surface 32e1, a vertical wall surface 32e2, and an inclined surface 32e3. The bottom wall surface 32e1 has a shape that extends perpendicular to the direction of movement of the movable core 30, the vertical wall surface 32e2 has a shape that extends from the bottom wall surface 32e1 in the direction of movement of the movable core 30, and the inclined surface 32e3 has a shape that extends from the vertical wall surface 32e2 to the groove opening 32e4, thereby increasing the flow area. In a Fig. In the example shown in Figure 14, the sloping surface 32e3 has a shape that extends linearly from an upper end of the vertical wall surface 32e2.

[0100] Examples of machining methods for the communication grooves 32e include laser machining, electrical discharge machining (EDM), end milling, and similar processes. First, a groove with a rectangular cross-section, including the vertical wall surface 32e2 and the lower wall surface 32e1, is machined. At this stage, a burr generated during machining may remain in the circumferential section of the groove opening 32e4 and in the vertical wall surface 32e2. Subsequently, however, the tapered surface 32e3 with a trapezoidal cross-section is machined to remove the burr.

[0101] When the fuel present in the fuel storage chamber B1 is compressed while the movable core 30 moves to the side opposite the nozzle openings, the movement of the movable core 30 is impeded. This reduces the speed of movement (collision velocity) when the movable core 30 moves a predetermined amount and contacts the needle 20. As a result, the aforementioned effect of the core boost structure—that is, the effect that the valve body can be actuated to open even with high-pressure fuel, while reducing the magnetic attraction force required to open the valve—is diminished. Furthermore, because the movement of the movable core 30 is impeded, there is a large variation in the valve opening timing of the needle 20 and a large variation in the fuel injection quantity.

[0102] On the other hand, according to the present embodiment, the fuel injection valve 1 comprises the needle 20 (valve body), the fixed core 13, the movable core 30, the first spring element SP1 (spring element), and the cup 50 (element for transmitting the valve closing force or a valve closing force transmission element). The movable core 30 contacts the needle 20 at a point in time when the movable core 30 is attracted by the fixed core 13 and moved by a predetermined amount to the side opposite the nozzle openings, thus opening the needle 20. During the process of opening the valve, the first spring element SP1 is elastically deformed, and the valve exhibits an elastic closing force for closing the needle 20.The cup 50 is arranged so that it is movable relative to the needle 20, and when the cup 50 is moved relative to the side of the nozzle opening, the cup 50 contacts the needle 20 to transmit the elastic closing force of the valve to the needle 20. The movable core 30 has the first core contact surface 32c and the second core contact surface 32b, and the communication grooves 32e are provided in the first core contact surface 32c and the second core contact surface 32b to connect the inside and outside of the fuel storage chamber B1.

[0103] When the movable core 30 moves to the side opposite the nozzle openings, the fuel accumulated in the fuel storage chamber B1 flows outwards through the communication grooves 32e. This inhibits the compression of the fuel accumulated in the fuel storage chamber B1, allowing the movable core 30 to move freely. Consequently, the reduction in the collision speed of the movable core 30 is inhibited, thus promoting the reduction of the magnetic attraction force by the core boost structure. Furthermore, because the movable core 30 moves freely, the variation in the valve opening timing of the needle 20, and therefore the variation in the fuel injection quantity, can be reduced.

[0104] Furthermore, in the fuel injection valve 1 according to the present embodiment, the plurality of communication grooves 32e are provided, and the multiple connection grooves 32e are arranged at regular intervals in the circumferential direction, as seen from the direction of movement of the movable core 30.

[0105] According to the configuration above, the sections or parts that easily flow outwards from the fuel storage chamber B1 are present at regular intervals in the axial direction. Therefore, when the movable core 30 moves in the axial direction, any change in the inclination direction of the movable core 30 with respect to the axial direction can be reduced. Since the behavior of the movable core 30 can be prevented from becoming unstable, the variation in the valve opening behavior can be further reduced. If three or more communication grooves 32e are provided at regular intervals in the circumferential direction, the effect of inhibiting behavioral instability is enhanced.

[0106] Furthermore, according to the present embodiment, the movable core 30 in the fuel injection valve 1 comprises the inner core 32 (contact section) and the outer core 31 (core body section), which are made of a different material than the inner core 32. The inner core 32 is formed by the first core contact surface 32c and the second core contact surface 32b, and the outer core 31 is formed by the movable core surface 31c facing the fixed core 13. The outer core 31 is excluded from a region in which the communication grooves 32e are provided.

[0107] Since the surface 31c of the outer core 31 facing the movable core can have a flat shape without a groove, the magnetic attraction force drawn by the fixed core 13 cannot be reduced by the communication grooves.

[0108] Furthermore, in the fuel injection valve 1 according to the present embodiment, the third core contact surface 32d of the movable core 30, which contacts the guide element 60, is located outside the fuel storage chamber B1. The communication grooves 32e are also provided in the third core contact surface 32d in addition to the first core contact surface 32c and the second core contact surface 32b.

[0109] When the needle 20 is in the full-stroke position, the inner core 32 touches the guide element 60. In the aforementioned contact state, if the stopper contact end surface 61a of the guide element 60 and the third core contact surface 32d of the inner core 32 are in close contact, there is a concern that a phenomenon (bonding phenomenon) will occur in which the third core contact surface 32d is barely separated from the stopper contact end surface 61a. Since the communication grooves 32e are also provided in the third core contact surface 32d in the present embodiment, fuel will be supplied to the third core contact surface 32d in a state of contact between the stopper contact end surface 61a and the third core contact surface 32d when the movable core 30 begins to move towards the nozzle opening side with the excitation switched off.Since the movable core 30 can be prevented from coming into close contact with the guide element 60 and can only separate from it with difficulty, the possibility that the start of the movement of the movable core 30 towards the nozzle opening side is delayed due to the aforementioned adhesion force can be reduced. Therefore, the response time of the valve closing, from the switching off of the excitation until the closing of the needle 20, can be reduced, and the valve closing behavior can be improved.

[0110] Furthermore, in the fuel injection valve 1 according to the present embodiment, the communication grooves 32e each have the lower wall surface 32e1, which extends perpendicular to the direction of movement of the movable core 30, and the vertical wall surface 32e2, which extends from the lower wall surface 32e1 in the direction of movement.

[0111] To remove burrs that form in the groove opening 32e4 of the communication grooves 32e, it is desirable to polish the first core contact surface 32c and the second core contact surface 32b. For example, polishing is carried out by a two-point catenary line in Fig. The polishing process is carried out in the position shown in section 14 and in the position shown by a solid line. In the present embodiment, after the inner core 32 has been assembled with the outer core 31, the communication grooves 32e and the outer communication grooves 31e are created by cutting or similar means, and then the polishing process mentioned above is carried out simultaneously on the outer core 31 and the inner core 32.

[0112] In contrast to the present embodiment, in the case where the vertical wall surface 32e2 is absent and the shape is represented by a single-point catenary, the cross-sectional area of ​​the communication grooves 32e becomes small, and the ratio of the cross-sectional area to be polished to the cross-sectional area of ​​the communication grooves 32e becomes large. Consequently, the influence of the polishing depth variation on the cross-sectional area of ​​the communication grooves 32e becomes significant, resulting in a large variation in the cross-sectional area of ​​the communication grooves 32e. For this reason, the degree of fuel exiting the fuel storage chamber B1 through the communication grooves 32e also becomes large, as does the mobility of the movable core 30, thus hindering a reduction in the variation of the valve opening timing of the needle 20.On the other hand, according to the present embodiment, since the vertical wall surface 32e2 is provided, the ratio of the cross-sectional area to be polished becomes small, and the influence of the variation in polishing depth on the cross-sectional area of ​​the communication grooves 32e becomes small. For this reason, the fluctuation in the degree of fuel outflow from the fuel storage chamber B1 to the outside through the communication grooves 32e is reduced, and the variation in the valve opening time of the needle 20 can be promoted. [Modification B1]

[0113] Although the in Fig. The communication grooves 32e shown in section 12 are not provided in the outer core 31, as shown in Fig. As shown in Figure 15, in addition to the communication slots 32e provided in the inner core 32, communication slots (outer communication slots 31e) can be provided in the outer core 31. In a Fig. In the example shown in Figure 15, the inner diameter-side end section of the outer communication grooves 31e communicates directly with the outer diameter-side end section of the communication grooves 32e.

[0114] As in Fig. As shown in Figure 16, several (e.g., four) outer communication grooves 31e are provided and arranged at regular intervals in the circumferential direction in the direction of movement of the movable core 30. Each of the outer communication grooves 31e has a shape extending linearly in the radial direction. The circumferential position of the outer communication grooves 31e differs from the circumferential position of the through-openings 31a.

[0115] The outer communication slots 31e and the communication slots 32e are in the same position circumferentially. In an example of Fig. 16. Four outer communication grooves 31e are arranged at regular intervals in the circumferential direction, but six outer communication grooves 31e can be arranged at regular intervals in the circumferential direction. In this case, it is desirable to determine the position of the through-openings 31a in the circumferential direction such that the circumferential distance to the adjacent outer communication grooves 31e is the same.

[0116] The outer communication grooves 31e extend radially across the entire surface of the outer core 31 and from the inner circumferential surface to the outer circumferential surface of the outer core 31. In other words, the outer communication grooves 31e extend radially across the entire surface 31c facing the movable core. The cross-sectional shape of the outer communication grooves 31e is the same as that shown in Fig. The cross-sectional shape of the communication grooves 32e shown in Figure 14, and the outer communication grooves 31e, have the same bottom wall area, vertical wall area, and inclined surface as the communication grooves 32e. As described above, Fig. 14 a sectional view along a line XIV-XIV of Fig. Figure 13 shows the cross-sectional shape of the communication groove 32e, which extends in the radial direction of the movable core 30, and which was taken perpendicular to the direction of extension. The cross-sectional shape of the outer communication grooves 31e is the same as that of the communication grooves 32e, and the cross-sectional shape has a lower wall surface, a vertical wall surface and a tapered surface in a cross-section of the outer communication grooves 31e, taken perpendicular to the direction of extension.

[0117] As described above, after the present modification with the outer communication grooves 31e, since the fuel flowing out of the outer diameter-side end section of the communication grooves 32e diffuses through the outer communication grooves 31e, an increase in fuel pressure at the outer diameter-side end section of the communication grooves 32e is prevented and the fuel flowing through the communication grooves 32e is conveyed. This prevents an increase in fuel pressure between the guide element 60 and the inner core 32.

[0118] Since, in the present modification, the end section on the inner diameter side of the outer communication grooves 31e communicates directly with the outer diameter-side end section of the communication grooves 32e, the outflow of fuel from the end section on the outer diameter side can be further promoted.

[0119] Since the outer communication grooves 31e extend radially over the entire surface of the surface 31c facing the movable core, in the present modification the fuel exiting the outer diameter-side end section of the outer communication grooves 31e flows directly into the gap between the inner circumferential surface of the holder and the outer circumferential surface of the outer core 31. For this reason, an increase in fuel pressure at the outer diameter-side end section of the outer communication grooves 31e can be prevented, and fuel flow through the communication grooves 32e and the outer communication grooves 31e can be promoted.

[0120] Furthermore, in the present modification, with regard to the dimensions of the outer communication grooves 31e, the width dimension (circumferential dimension) of a section of the outer communication grooves 31e opening towards the fixed core 13 is set smaller than the depth dimension (axis dimension C) of the outer communication grooves 31e. According to the above configuration, the cross-sectional area of ​​the flow channel of the outer communication grooves 31e can be increased, while a reduction in the area 31c facing the moving core, caused by the provision of the outer communication grooves 31e, can be prevented. The "flow channel cross-sectional area" is an area with a cross-section perpendicular to the flow direction when the fuel flows radially outwards through the outer communication grooves 31e in the fuel storage chamber B1.In other words, since the width dimension is smaller than the depth dimension, as described above, fuel discharge from the fuel storage chamber B1 can be realized at the time of the valve opening process, while preventing a reduction in the magnetic attraction force. [Modification B2]

[0121] In the present case, in Fig. 17 and Fig. In the modification shown in Figure 18, a connecting groove 32f is provided for connecting the multiple communication grooves 31e. The connecting groove 32f has an annular shape extending around the through-hole 32a and connects all (four in one example of Fig. 18) Communication grooves 31e with each other. The connecting groove 32f connects the outer diameter-side end section of the communication grooves 31e. The connecting groove 32f is produced by cutting the outer diameter-side edge section of the inner core 32. In addition, the inner diameter-side edge section of the outer core 31 is cut such that the connecting groove 32f extends over both the outer core 31 and the inner core 32.

[0122] In the Fig. 15 and Fig. The embodiment shown in 16 can also be the one described in the Fig. 17 and Fig. 18 connection groove 32f shown are provided, and each of the several communication grooves 32e and the several outer communication grooves 31e can be connected to each other by the connection groove 32f.

[0123] As described above, after the present modification with the connecting groove 32f, since the fuel flowing out of the outer diameter-side end section of the communication grooves 32e diffuses through the connecting groove 32f, an increase in the fuel pressure at the outer diameter-side end section of the communication grooves 32e is prevented and the fuel flowing out through the communication grooves 32e is conveyed.

[0124] Furthermore, by connecting the multiple communication grooves 31e, a change in the inclination direction of the movable core 30 with respect to the axial direction can be prevented when the movable core 30 moves axially, since the fuel can be conveyed for a uniform flow from the multiple communication grooves 31e. Because the behavior of the movable core 30 can be prevented from becoming unstable, the variation in the valve opening behavior can be further reduced. [Modification B3]

[0125] The in Fig. The communication grooves 32e shown in Figure 12 are formed over the entire front face of the inner core 32. On the other hand, communication grooves 32g are shown according to the diagram in Figure 12. Fig. 19 and Fig. The modification shown in Figure 20 provides communication grooves 32g over a portion of the first core contact surface 32c, the entire surface of the second core contact surface 32b, and a portion of the third core contact surface 32d. More precisely, the communication grooves 32g are not provided over the entire surface of the first core contact surface 32c in the radial direction, but only partially in a section of the first core contact surface 32c that adjoins the second core contact surface 32b. The communication grooves 32g are provided over the entire surface of the second core contact surface 32b in the radial direction. The communication grooves 32g are not provided over the entire surface of the third core contact surface 32d in the radial direction, but only partially in a section of the third core contact surface 32d that adjoins the second core contact surface 32b.

[0126] The in Fig. The communication grooves 32e shown in Figure 12 have a shape extending linearly in the radial direction, whereas the communication grooves 32g, according to the present modification, have an oblique shape. In other words, as shown in Fig. As shown in Figure 20, the communication slots 32g are circular when viewed from the direction of axis line C, and as in Fig. As shown in Figure 19, the communication grooves 32g are triangular in cross-sectional view.

[0127] As described above, according to the present modification with the inclined communication grooves 32g, the communication grooves 32g can be produced only by pressing a drill blade tip against the movable core 30, and therefore the communication grooves 32g can be easily machined. [Modification B4]

[0128] In the Fig. In the embodiment shown in Figure 12, the communication grooves 32e are provided in the contact surface of the movable core 30, so that the inner and outer sides of the fuel storage chamber B1 communicate with each other. In the present modification, which is shown in Fig. In contrast, as shown in 21, the interior of the fuel storage chamber B1 and the inner passage 20a of the needle 20 are connected by providing connecting openings 20c in the needle 20.

[0129] In a state where the cup 50 contacts the valve closing contact surface 21b and in a state where the cup 50 contacts the second core contact surface 32b, the connecting openings 20c are arranged at a position including the first core contact surface 32c in the direction of the axis line C. Alternatively, all connecting openings 20c are arranged on the side opposite the nozzle openings with respect to the first core contact surface 32c. Multiple connecting openings 20c are provided and are arranged at regular intervals in the circumferential direction, viewed from the direction of movement of the needle 20. The connecting openings 20c have a shape that extends linearly in the radial direction of the needle 20.

[0130] As described above, after the present modification, in which the connecting openings 20c are provided in the needle 20, the fuel accumulated in the fuel storage chamber B1 flows out through the connecting openings 20c into the inner passage 20a (the outside) of the needle 20 when the movable core 30 moves to the side opposite the nozzle openings. Therefore, the compression of the fuel accumulated in the fuel storage chamber B1 is inhibited, allowing the movable core 30 to move freely. Consequently, the reduction in the collision speed of the movable core 30 can be inhibited, thus promoting the effect of reducing the magnetic attraction force through the core boost structure. Furthermore, because the movable core 30 moves freely, the variation in the valve opening timing of the needle 20, and therefore the variation in the fuel injection quantity, can be reduced. [Modification B5]

[0131] In the present case, in Fig. In the modification shown in Figure 22, sliding surface communication grooves 20d are provided in the needle 20, so that the interior of the fuel storage chamber B1 and the inner passage 20a of the needle 20 communicate with each other. The sliding surface communication grooves 20d are located in the valve body-side sliding surface 21c (see Figure 22). Fig. 7) provided for the needle 20, on which the cup 50 slides.

[0132] The majority of the sliding surface communication grooves 20d are provided, and the majority of the sliding surface communication grooves 20d are arranged at regular intervals in the circumferential direction, viewed from the direction of movement of the needle 20. The sliding surface communication grooves 20d each have a shape that extends linearly in the direction of the axis line C of the needle 20.

[0133] As described above, after the present modification, in which the sliding surface communication grooves 20d are provided in the valve body-side sliding surface 21c, which is the sliding surface between the needle 20 and the cup 50, the fuel accumulated in the fuel storage chamber B1 flows outwards through the sliding surface communication grooves 20d when the movable core 30 moves to the side opposite the nozzle openings. In this description, the outside is a gap between the valve closing contact surface 21b and the valve closing force transmission contact surface 52c and the inner passage 20a. Therefore, the compression of the fuel accumulated in the fuel storage chamber B1 is inhibited, allowing the movable core 30 to move freely.For this reason, the reduction in the collision speed of the movable core 30 can be inhibited, thus promoting the effect of reducing the magnetic attraction force through the core boost structure. Furthermore, since the movable core 30 can move easily, the variation in the valve opening timing of the needle 20, and therefore the variation in the fuel injection quantity, can be reduced. [Modification B6]

[0134] In the present case, in Fig. In the modification shown in Figure 23, second sliding surface communication grooves 32h are provided in the inner core 32h, so that the interior of the fuel storage chamber B1 and the movable chamber 12a are connected to each other. The second sliding surface communication grooves 32h are provided on the surface of the inner core 32 on which the needle 20 slides, i.e., on the inner circumferential surface of the inner core 32.

[0135] Multiple second sliding surface communication grooves 32h are provided, and these grooves are arranged at regular intervals in the circumferential direction, viewed from the direction of movement of the movable core 30. Each second sliding surface communication groove 32h has a shape that extends linearly in the direction of the axis line C of the movable core 30.

[0136] As described above, according to the present modification, in which the second sliding surface communication grooves 32h are provided on the sliding surface between the needle 20 and the inner core 32, the fuel accumulated in the fuel storage chamber B 1 flows through the communication grooves of the second sliding surface 32h into the movable chamber 12a (the outer side) when the movable core 30 moves to the side opposite the nozzle openings. Therefore, the compression of the fuel accumulated in the fuel storage chamber B 1 is inhibited, allowing the movable core 30 to move freely. Consequently, the reduction in the collision velocity of the movable core 30 can be inhibited, thus promoting the effect of reducing the magnetic attraction force through the core boost structure.Since the movable core 30 can be moved easily, the variation in the valve opening time of the needle 20 and thus the variation in the fuel injection quantity can also be reduced. <Detaillierte Beschreibung der Konfigurationsgruppe C>

[0137] Next, among the configurations of the fuel injection valve 1 according to the present embodiment, a configuration group C is defined, comprising at least one supply flow channel to be described below and a configuration related to the supply flow channel with reference to the Fig. Sections 24 to 26 and 12 are described in detail. Furthermore, a modification of configuration group C will be described later with reference to the Fig. 27 to 35 described.

[0138] As in Fig. As shown in Figure 24, main flow channels 20e with grooves are provided in the valve closing contact surface 21b of the needle 20. As shown in Fig. As shown in Figure 25, the valve closing contact surface 21b is formed in a region that extends annularly from the direction of movement of the movable core 30, and the main flow channels 20e are each shaped such that they extend to connect an annular inner surface and an annular outer surface over an annular region in which the valve closing contact surface 21b is formed. The main flow channels 20e each have a straight section 201 that extends linearly from the direction of movement of the movable core. In the present embodiment, the entirety of the main flow channels 20e corresponds to the entirety of the straight section 201.

[0139] The annular inner surface corresponds to an inner passage 20a of the needle 20. The annular outer surface corresponds to a gap B2 (see Fig. 12) between the inner surface of the cup 50 and the outer surface of the needle 20, which is provided in a state in which the valve closing contact surface 21b touches the cup 50. Therefore, the main flow channels 20e communicate the inner passage 20a of the needle 20 with the gap B2 in a state in which the valve closing contact surface 21b touches the cup 50.

[0140] The main flow channels 20e (supply flow channels) each have a shape extending such that they connect an inner circumferential surface of the needle 20, defining the inner passage 20a, and an outer circumferential surface of the needle 20. The outer circumferential surface of the needle 20 acts as the wall surface of a passage through which the fuel flows through the nozzle openings 11a. The fuel flowing through the passage formed by the gap between the outer circumferential surface of the needle 20 and the inner circumferential surface of the cylindrical section 51 flows into the fuel storage chamber B1. Subsequently, the fuel flows through a gap between the inner circumferential surface of the movable core 30 and the outer circumferential surface of the needle 20, and a gap between the outer circumferential surface of the movable core 30 and the inner circumferential surface of the main body 12, into the movable chamber 12a and flows through the flow channel 12b into the nozzle openings 11a.

[0141] As in Fig. As shown in Figure 25, an inner circumferential edge section 201a and an outer circumferential edge section 201b of the valve closing contact surface 21b in the needle 20 are chamfered. The main flow channels 20e (supply flow channels) each have a shape that connects the inner circumferential edge section 201a and the outer circumferential edge section 201b.

[0142] As in Fig. As shown in Figure 25, several (e.g., four) main flow channels 20e are provided, wherein the several main flow channels 20e are arranged at regular intervals in the circumferential direction in the direction of movement of the movable core 30. In other words, the several main flow channels 20e are arranged at regular intervals in the circumferential direction on the valve closing contact surface 21b of the needle 20. The main flow channels 20e each have a shape that extends linearly in the radial direction. Each of the several main flow channels 20e has the same shape. As shown in Fig. As shown in Figure 26, the cross-section of the straight section 201 of the main flow channels 20e has a shape with an arcuate bottom surface that is convex towards the nozzle opening side. The edge sections of the outer circumferential section and the inner circumferential section of the contact section 21 of the needle 20 are chamfered, and the outer circumferential section and the inner circumferential section of the contact section 21 are conically shaped.

[0143] A depth dimension 201h of the main flow channels 20e is defined as a dimension of the main flow channels 20e in the direction of the axis line C, and a width dimension 201w of the main flow channels 20e is defined as a dimension of the needle 20 around the direction of the axis line C (see Fig. 24). The depth dimension 201h of the main flow channels 20e is larger than the width dimension 201w of the main flow channels 20e.

[0144] In the case of the core-boost structure, where the cup 50 touches the needle 20 at the moment when the movable core 30, together with the cup 50, begins to move by a predetermined amount due to the start of coil excitation, the following concern arises. In other words, if the cup 50 and the needle 20 are in close contact and touching each other, the phenomenon occurs that the cup 50 is difficult to separate from the needle 20 (chaining phenomenon), thus delaying the start of the movement of the movable core 30 by a predetermined amount, which leads to the concern that the valve opening behavior will be degraded.

[0145] To address the aforementioned problem, the present embodiment comprises the needle 20 (valve body), the fixed core 13, the movable core 30, the first spring element SP1 (spring element), and the cup 50 (element for transmitting the valve closing force). When the movable core 30 is attracted by the fixed core 13 and moved by a predetermined amount, the movable core 30 contacts the valve opening contact surface 21a formed on the needle 20 and actuates the needle 20 to open the valve. During the valve opening process, the first spring element SP1 elastically deforms the needle 20, and the valve exerts an elastic closing force, or valve closing force, to close the needle 20. The cup 50 contacts the valve closing contact surface 21b formed on the needle 20 and transmits the elastic valve closing force to the needle 20.When the movable core 30, together with the cup 50, begins to move by the predetermined amount, the cup 50 contacts the valve closing contact surface 21b. The needle 20 has the main flow channels 20e (supply flow channels) for supplying fuel to the valve closing contact surface 21b in the contact state with the cup 50.

[0146] When the movable core 30 begins to move by the predetermined amount, the fuel is supplied to the valve closing contact surface 21b in a state where the movable core 30 is in contact with the cup 50. This reduces the likelihood that the cup 50 will not make close contact with the needle 20 and will be difficult to separate from it. As a result, the start of the movable core 30's movement is delayed by the predetermined amount due to the aforementioned force of close contact. Therefore, the valve opening response time, from the start of coil 17 excitation to the start of needle 20 opening, is shortened, and the valve opening behavior is improved. Furthermore, the variation in the valve opening time due to the restraint of the movable core 30's movement is reduced, thus minimizing the variation in the fuel injection quantity.

[0147] Furthermore, in the fuel injection valve 1 according to the present embodiment, the main flow channels 20e (supply flow channels) are formed by the grooves provided in the valve closing contact surface 21b of the needle 20. For this reason, the machining of the supply flow channels can be simplified, and the supply flow channels can be easily provided compared to the case where the through-holes are provided as supply flow channels in the needle 20 or the cup 50.

[0148] Furthermore, in the fuel injection valve 1 according to the present embodiment, the valve closing contact surface 21b is formed in an annular region, extending in the direction of movement of the movable core 30, and the main flow channels 20e of the supply flow channels extend such that they connect the annular inner and outer surfaces across this region. For this reason, the fuel is supplied from both sides of the annular inner and outer surfaces of the valve closing contact surface 21b, thus promoting the reduction of the coupling phenomenon through the aforementioned close contact.

[0149] Furthermore, in the fuel injection valve 1 according to the present embodiment, multiple main flow channels 20e are provided, and these multiple main flow channels 20e are arranged at regular intervals in the circumferential direction, as viewed from the direction of movement of the movable core 30. According to the above configuration, the sections in which a force from the cup 50, which comes into close contact with the needle 20, is relieved or absorbed, are located at regular intervals in the axial direction. Once the movable core 30 begins to move by the predetermined amount in the axial direction, the inclination direction of the movable core 30 with respect to the axial direction can no longer be changed. Since the behavior of the movable core 30 can be prevented from becoming unstable, the variation in the valve opening behavior can be further reduced.If three or more main flow channels 20e are provided at regular intervals in the circumferential direction, the effect of reducing behavioral instability is promoted.

[0150] If, in this example, the depth dimension 201h of the main flow channels 20e is too small, and the cross-sectional area of ​​the main flow channels 20e decreases with progressive wear of the valve closing contact surface 21b, the flow rate of the fuel flowing through the main flow channels 20e cannot be adequately ensured. If the width dimension 201w of the main flow channels 20e is too large, the surface pressure when the cup 50 is pressed against the needle 20 by the elastic valve closing force becomes too high, and the pressure-bearing area of ​​the valve closing contact surface 21b cannot be adequately secured. This accelerates the wear progression of the valve closing contact surface 21b.

[0151] In light of the above points, according to the present embodiment, the depth dimension 201h of the main flow channels 20e in the fuel injection valve 1 is set larger than the width dimension 201w of the main flow channels 20e. For this reason, the flow rate of the fuel flowing through the main flow channels 20e can be sufficiently ensured, and the progression of wear on the valve closing contact surface 21b due to excessive surface pressure can be prevented. [Modification C1]

[0152] In the present modification, the cross-sectional shape of the main flow channels 20e is modified. In other words, the straight section 201 of the Fig. The main flow channels 20e shown in Figure 26 have a cross-sectional shape with an arcuate bottom surface. Alternatively, the straight section 201 can have a triangular cross-sectional shape, as shown in Figure 26. Fig. 27 shown, or have a rectangular cross-sectional shape, as in Fig. 28 shown.

[0153] As in Fig. As shown in Figure 29, the straight section 201 can have a cross-sectional shape that combines a rectangle with a trapezoid. Specifically, the main flow channels 20e each have a bottom wall surface 20e1, a vertical wall surface 20e2, and an inclined surface 20e3. The bottom wall surface 20e1 has a shape that extends perpendicular to the direction of movement of the movable core 30, the vertical wall surface 20e2 has a shape that extends from the bottom wall surface 20e1 in the direction of movement, and the inclined surface 20e3 has a shape that extends from the vertical wall surface 20e2 to a groove opening 20e4, thereby increasing the flow area. In a Fig. In the example shown in Figure 29, the sloping surface 20e3 has a shape that extends linearly from an upper end of the vertical wall surface 20e2.

[0154] As a processing method of the in Fig. Figure 29 illustrates the main flow channels 20e, demonstrating laser processing, electrical discharge machining (EDM), machining with an end mill, and similar processes. First, a groove with a rectangular cross-section, including the vertical wall surface 20e2 and the lower wall surface 20e1, is machined. At this stage, burrs generated during or at the time of processing may remain in a circumferential section of the groove opening 20e4 on the vertical wall surface 20e2. Subsequently, however, these burrs are removed by machining the inclined surface 20e3 with a trapezoidal cross-section. [Modification C2]

[0155] In the present case, in Fig. In the modification shown in Figure 30, the supply flow channel includes a branch flow channel 205 that branches off from the main flow channels 20e and connects them, in addition to the straight sections 201, which are the main flow channels 20e. The branch flow channel 205 has an annular shape when viewed from the direction of movement of the movable core 30. In particular, the branch flow channel 205 has a ring shape that surrounds the inner passage 20a. The branch flow channel 205 has a groove shape with the same depth as the straight section 201. The branch flow channel 205 has a shape that extends around the entire circumference to connect all the main flow channels 20e.

[0156] In one example of Fig. 25 Four main flow channels 20e are provided; however, in the present modification, eight main flow channels 20e are provided, and the multiple main flow channels 20e are arranged at regular intervals in the circumferential direction, viewed from the direction of movement of the movable core 30. A branch flow channel 205 with an annular shape is provided.

[0157] In one example of Fig. 25 The valve closing contact surface 21b is divided circumferentially by the straight section 201. On the other hand, in the present modification in Fig. 30, since the branch flow channel 205 is provided in addition to the straight section 201, the valve closing contact surface 21b is divided in the radial direction in addition to the division in the circumferential direction.

[0158] In a state where the needle 20 touches the cup 50, a portion of the fuel flowing into the main flow channels 20e from both sides of the annular inner and outer surfaces is supplied to the valve closing contact surface 21b from the circumferential direction. Furthermore, the fuel that has flowed into the branch flow channel 205 after entering the main flow channels 20e is supplied to the valve closing contact surface 21b from the radial direction.

[0159] As described above, in the present modification, the supply flow channel has, in addition to the main flow channels 20e, a branch flow channel 205, which connects the annular inner and outer surfaces. Therefore, the fuel is directed to the valve closing contact surface 21b from both the main flow channels 20e and the branch flow channel 205. This, through the close contact mentioned above, promotes a reduction of the bonding phenomenon.

[0160] Furthermore, according to the present modification, the branch flow channel 205 in the fuel injection valve has an annular shape when viewed from the direction of movement of the needle 20. For this reason, both ends of the branch flow channel 205 communicate with the main flow channels 20e, thus facilitating the flow of fuel from the main flow channels 20e to the branch flow channel 205 and the supply of fuel to the valve closing contact surface 21b. [Modification C3]

[0161] In the present modification, which is in Fig. As shown in Figure 31, the main flow channels 20e each have the straight sections 201 and the inlet sections 202. The straight sections 201 each have a shape that extends linearly from the direction of movement of the movable core 30. The inlet section 202 communicates with the straight section 201, thus forming an inlet port 203 for the fuel to the main flow channel 20e. A flow channel cross-section of the inlet section 202 has a larger shape than a flow channel cross-section of the straight section 201. In particular, in the figure shown in (b) Fig. In the sectional view shown in Figure 32, the inlet section 202 has a shape in which the groove width increases towards the nozzle opening. In a top view shown in Figure 32, the inlet section 202 has a shape in which the groove width increases towards the nozzle opening. Fig. As shown in Figure 31, the inlet section 202 has a shape in which the groove width increases towards the radially outer side.

[0162] Of the fuel inlet openings 203 and 204 provided at both ends of the main flow channels 20e, the inlet 203, located outside the aforementioned annular region, is provided with an inlet section 202 having an enlarged area. Conversely, the inlet 204, located within the annular region, is not provided with an inlet section having an enlarged area. The edge sections of the outer circumferential section and the inner circumferential section of the contact section 21 of the needle 20 are chamfered, and the outer circumferential section and the inner circumferential section of the contact section 21 are conically shaped.

[0163] The main flow channels 20e are manufactured by laser processing or by a laser process. A single-point catenary in Fig. Figure 32 shows the center of a laser beam. First, as shown in column (a) of Fig. Figure 32 shows a groove created by a laser in a section corresponding to the straight section 201. More precisely, the laser processing is started from the inside in a radial direction, and the laser beam is moved from the inside out. During the processing of the straight section 201, a focal point of the laser beam is aligned with a bottom surface of the groove.

[0164] After the laser beam has been moved to the outer end section of the straight section 201 to complete the processing of the straight section 201, the laser beam is moved further to the radially outer side, and the groove in the section corresponding to the inflow section 202 is processed by the laser, as shown in column (b) of Fig. Figure 32 illustrates this. The focal point of the laser beam at the time of processing the inlet section 202 is adjusted to coincide with the focal point of the laser beam at the time of processing the straight section 201. Since the outer circumferential section of the contact section 21 is conically shaped, the lower surface of the inlet section 202 is cut at a location other than the focal point of the laser beam. Because the cut width on the bottom surface of the inlet section 202 is greater than the cut width on the bottom surface of the straight section 201, the inlet section 202 is formed in a shape where the groove width is greater towards the nozzle opening side.

[0165] As described above, according to the present modification, the main flow channels 20e have the straight section 201, which extends linearly from the direction of movement of the movable core 30, and the inlet section 202, which connects to the straight section 201 to form the fuel inlet port 203. The cross-sectional area of ​​the inlet section 202 is shaped with a larger area compared to the cross-sectional area of ​​the straight section 201. Therefore, compared to the case where the inlet section 202 is not present, the fuel flows easily from the inlet port 203 into the straight section 201, thus facilitating the fuel supply to the valve closing contact surface 21b. [Modification C4]

[0166] The in Fig. The feed flow channel shown in Figure 24 is formed by the grooved main flow channel 20e in the needle 20. In contrast, in the present modification, which is shown in Fig. Figure 33 shows a through-hole 52d in the cup 50, and the through-hole 52d provides a supply flow channel for the supply of fuel to the valve closing contact surface 21b.

[0167] According to the configuration above, when the movable core 30 begins to move by a predetermined amount, the fuel of the flow channel 13a is supplied to the valve closing contact surface 21b in a state where the movable core 30 contacts the cup 50 through the through-opening 52d. For this reason, similar to the embodiment of Fig. 24, the responsiveness of the valve opening is improved and the variation in the fuel injection quantity due to the variation in the valve opening time is reduced, as it can be prevented that the cup 50 comes into close contact with the needle 20 and is difficult to separate from the needle 20. [Modification C5]

[0168] In the Fig. In the feed flow channel shown in 24, the grooved main flow channels 20e are provided in the needle 20. On the other hand, in the present, in Fig. 34 and Fig. In the modification shown in Figure 35, a grooved main flow channel 210e is provided in a plate 210, which is described below.

[0169] The plate 210 is arranged between the needle 20 and the cup 50 and is circular, plate-shaped, and made of metal. In the illustrated example, the main flow channel 210e is provided on the surface of the plate 210 on the nozzle opening side; alternatively, it can be formed on the surface of the plate 210 on the side opposite the nozzle opening. Several (e.g., four) main flow channels 210e are provided, and these channels are arranged at regular intervals in the circumferential direction, viewed from the direction of movement of the movable core 30. The main flow channels 210e each have a linear shape extending radially. All the main flow channels 210e have the same shape.

[0170] The main flow channels 210e each have a shape that extends such that they form the annular inner and outer surfaces over the annular area in which the valve closing contact surface 21b is formed, in the same way as in Fig. The main flow channels 20e shown in the diagram connect. Therefore, the main flow channels 210e each communicate the inner passage 20a of the needle 20 with the gap B2 in a state in which the valve closing contact surface 21b touches the cup 50 through the plate 210.

[0171] The plate 210 is not coupled to the needle 20 and the cup 50, but is defined as part of the needle 20 or the cup 50. A through-opening 52a of the cup 50 and a through-opening 210a, which is connected to the inner through-opening 20a of the needle 20, are provided in the plate 210.

[0172] As described above, according to the present modification, when the movable core 30 begins to move by a predetermined amount, the fuel in the flow channel 13a of the valve closing contact surface 21b is supplied in a state in which the movable core 30 contacts the cup 50 through the plate 210 via the main flow channel 210e. For this reason, similar to the embodiment of Fig. 24, the needle 20 is prevented from coming into close contact with the plate 210 and is difficult to separate from the plate 210, the response of the valve opening is improved and the variation in the fuel injection quantity due to the variation in the valve opening time is reduced. [Modification C6]

[0173] The in Fig. The supply flow channel shown in Figure 24 is formed by the grooved main flow channel 20e in the valve closing contact surface 21b of the needle 20. In the present modification, however, the main flow channel 20e is eliminated, and the supply flow channel is formed by irregularities described below. In other words, shot peening, to collide an abrasive material with the valve closing contact surface 21b, is performed to increase the surface roughness of the valve closing contact surface 21b, thus providing the valve closing contact surface 21b with irregularities. These irregularities are replaced by the main flow channel 20e, which forms the supply flow channel. In other words, the surface roughness of the valve closing contact surface 21b is made rougher than that of the inner circumferential surface of the part that forms the inner passage 20a of the surface of the needle 20.Alternatively, the surface roughness of the valve closing contact surface 21b is made rougher than that of the outer circumferential surface of the needle 20.

[0174] The unevenness of the valve closing contact surface 21b increases the hardness of the valve closing contact surface 21b due to shot peening. Therefore, the wear resistance of the valve closing contact surface 21b can be improved by the repeated collision of the cup 50 with the needle 20.

[0175] Instead of blasting the needle 20 as described above to create the irregularities, blasting can also be carried out on the contact surface 52c of the closing force transmission of the valve of the cup 50 to create the irregularities. In this case, the supply flow channel is formed by the irregularities that form on the contact surface 52c of the valve closing force transmission. <Detaillierte Beschreibung der Konfigurationsgruppe D>

[0176] Next, among the configurations of the fuel injection valve 1 according to the present embodiment, a configuration group D with at least one recessed surface 60a, which is described below, and a configuration related to the recessed surface 60a with reference to the Fig. 36 and Fig. 37 described in detail.

[0177] As described above, the inner circumferential surface of the cylindrical section 61 of the guide element 60 forms the sliding surface 61b, which slides with the outer circumferential surface 51d of the cylindrical section 51 of the cup 50. The sliding surface 61b displaces the outer circumferential surface 51d of the cup 50 to guide the movement of the cup 50 in the direction of the axis C and simultaneously limit the movement of the cup 50 in the radial direction. The sliding surface 61b is a surface with a shape that runs parallel to the direction of the axis C.

[0178] The recessed surface 60a is formed on a surface of the inner surface of the guide element 60 that is connected to the side opposite the nozzle openings of the sliding surface 61b. The recessed surface 60a is shaped such that it is recessed in a direction that increases the gap to the cup 50 in the radial direction. The recessed surface 60a has a shape that extends annularly around the axis C and has the same shape in every cross-section in the circumferential direction.

[0179] A surface 60a1 of the recessed surface 60a adjacent to the sliding surface 61b is a surface connected to the sliding surface 61b on the side opposite the nozzle opening and is shaped such that it gradually increases a gap CL1 from the cup 50 in the radial direction as the distance from the sliding surface 61b increases. The adjacent surface 60a1 includes an oblique surface 60a2 that extends linearly in a cross-section that includes the axis line C. A boundary section 60b, or limiting section 60b, of the guide element 60, which forms a boundary between the adjacent surface 60a1 and the sliding surface 61b, has a shape that is curved such that it is convexly directed inwards in the radial direction, i.e., an R-shape. This prevents the cup 50 from being carried by the guide element 60.

[0180] A chamfered section 61c is provided on a section connecting the stopper contact end surface 61a and the sliding surface 61b. This chamfered section is formed by chamfering in an oblique shape. The edge section, including the boundary between the chamfered section 61c and the sliding surface 61b, has a radially inwardly convex shape and prevents the cup 50 from being worn by the guide element 60.

[0181] In the cup 50, an edge section 51g, which connects the outer circumferential surface 51d and the core contact end surface 51a, and an edge section 51h, which connects the transmission element-side sliding surface 51c and the core contact end surface 51a, are chamfered such that they have an oblique shape or an R-shape. An edge section 21d of the needle 20, which connects the valve body-side sliding surface 21c and the valve opening contact surface 21a, is also chamfered so that it has an oblique shape or an R-shape. A marginal section 21e, which includes a boundary between the chamfered section formed on the side opposite the nozzle opening with respect to the valve body sliding surface 21c and the valve body sliding surface 21c, has a shape that is curved in such a way that it is convex or bulged outwards in the radial direction and prevents wear between the cup 50 and the needle 20.

[0182] In the following description, a portion of the surface of the cup 50, comprising the outer circumferential surface 51d of the cylindrical section 51 of the cup 50 and extending parallel to the direction of the axis line C, is referred to as a parallel surface. In an example of Fig. 36 corresponds to the entire outer circumferential area 51d of a parallel surface, and an area that is in Fig. 37, indicated by the symbol M1, is a parallel surface in the surface of the cup 50.

[0183] Furthermore, a surface connected to the side opposite the nozzle openings of the parallel surface and located on the radially inner side of the parallel surface is designated as the connecting surface 51e. The connecting surface 51e is curved such that it projects convexly out of the cup 50 in the radial direction. A region is formed on the surface of the cup 50 that is Fig. The connecting surface 51e, designated by the symbol M2, is located at 37. The surface of the connecting surface 51e, which is connected to the side opposite the parallel surface, is a spring contact surface upon which the first elastic force is exerted by contact with the first spring element SP1. The spring contact surface has a shape that extends perpendicular to the direction of the axis line C.

[0184] A boundary line between the parallel surface and the connecting surface 51e is called the connecting boundary line 51f (see circle in Fig. 37). When the movable core 30 moves in the direction of the axis line C, the cup 50 also moves in the direction of the axis line C. A movable area M3 of the connecting boundary line 51f in the direction of the axis line C lies completely within an area N1 of the recessed surface 60a in the direction of the axis line C due to the above movement.

[0185] The outer circumferential surface of the guide element 60 is press-fitted into the section 13c with the enlarged diameter of the solid core 13. Because the guide element 60 is press-fitted into the solid core 13, it is not tilted relative to the solid core 13. However, a dimensional tolerance of the outer circumferential surface of the guide element 60 or the inner circumferential surface of the enlarged diameter section 13c is present. On the other hand, since the cup 50 is slidably arranged relative to the guide element 60, a sliding gap CL1 is provided between the cup 50 and the guide element 60. Accordingly, the cup 50 can be tilted relative to the solid core 13 and the guide element 60. In other words, the axis C of the cup 50 can be inclined with respect to the axis C of the solid core 13.

[0186] Since the needle 20 is slidably arranged on the cup 50, a sliding gap CL2 is provided between the needle 20 and the cup 50. Therefore, the needle 20 can be inclined further relative to the tiltable cup 50. In other words, the axis C of the needle 20 can be inclined further relative to the axis C of the tiltable cup 50. Therefore, an angle (maximum inclination angle) at which the needle 20 and the cup 50 are tilted maximally in the same direction as the needle 20 corresponds to the assumed maximum inclination angle θ2 (see Fig. 36), in which the cup 50 is tilted. The inclined surface 60a2 is shaped such that an angle of inclination θ1 (see Fig. 36), in which the inclined surface 60a2 is inclined relative to the sliding surface 61b of the guide element 60, is greater than the maximum inclination angle θ2 of the cup 50.

[0187] The gap CL1 between the parallel surface of the cup 50 and the sliding surface 61b of the guide element 60 is set larger than the gap CL2 between the cup 50 and the needle 20. Therefore, the inclination angle of the cup 50 when the gap CL2 is zero is larger than the inclination angle of the needle 20 when the gap CL1 is zero.

[0188] The sliding path between the cup 50 and the guide element 60 in the gap CL1 is set to be longer than the sliding path between the cup 50 and the needle 20 in the gap CL2. In this example, the inclination caused by the gap is smaller the longer the sliding path. For example, the longer the sliding path in the gap CL1, the smaller the inclination of the cup 50 relative to the guide element 60. The longer the sliding path in the gap CL2, the smaller the inclination of the needle 20 relative to the cup 50. Even when these two inclinations are at their maximum, the connecting surface 51e is set so that it does not touch the guide element 60.

[0189] The guide element 60 is made of a magnetic material, and the cup 50 is made of a non-magnetic material. Generally, a non-magnetic material has a lower hardness than a magnetic material. However, in the present embodiment, the cup 50 and the guide element 60 have the same hardness. In other words, a non-magnetic material with high hardness is used for the cup 50 instead of a general non-magnetic material. The hardness of the cup 50 (cup hardness) and the hardness of the guide element 60 (guide element hardness) are, for example, values ​​ranging from Vickers hardness HV600 to HV700. If the deviation of the guide element hardness with respect to the cup hardness is within a range of -10% to +10% of the cup hardness, both hardness grades are considered to be of equal hardness.

[0190] As wear progresses due to sliding between the cup 50 and the guide element 60, the cup 50 tilts considerably relative to the guide element 60, and consequently the needle 20 tilts considerably along with the cup 50. As the tilt of the needle 20 increases, the valve opening and closing timing of the needle 20 varies, and the variation in the fuel injection quantity increases.

[0191] To address the above-mentioned problem, the present embodiment comprises the needle 20 (valve body), the fixed core 13, the movable core 30, the first spring element SP1 (spring element), the cup 50 (element for transmitting the valve closing force) and the guide element 60.

[0192] The movable core 30 contacts the needle 20 at a point in time when the movable core 30 is attracted by the fixed core 13 and moved by a predetermined amount, causing the needle 20 to perform the valve opening operation. During the valve opening process, the first spring element SP1 elastically deforms the needle 20, and the valve exerts an elastic closing force, or valve closing force, to close the needle 20. The cup 50 has a valve body transmission section (circular plate part 52) ​​that contacts the first spring element SP1 and the needle 20 to transmit the elastic valve closing force to the needle 20, and a cylindrical section 51 that pushes the movable core 30 toward the nozzle openings.The guide element 60 has a sliding surface 61b that displaces the outer circumferential surface 51d of the cylindrical section 51 such that the movement of the cylindrical section 51 is guided in the direction of the axis line C and its movement in the radial direction is limited. The guide element 60 is provided with the recessed surface 60a, which is a surface connected to the sliding surface 61b on the side opposite the nozzle opening and which is recessed in a direction that increases the gap with the cup 50 in the radial direction. The valve body transmission section is a circular plate part 52 with a circular plate shape, and the cylindrical section 51 is a shape that extends from the outer circumferential edge of the circular plate of the circular plate part 52 towards the nozzle opening side.

[0193] The surface of the cup 50 includes a surface that encloses the outer circumferential surface of the cylindrical section 51 and extends parallel to the direction of the axis line C; a surface connected to the parallel surface on the side opposite the nozzle openings and located on the radially inner side of the parallel surface is the connecting surface 51e; and a boundary line between the parallel surface and the connecting surface 51e is the connecting boundary line 51f. The movable area M3 of the connecting boundary line 51f in the axial direction lies entirely within an area N1 of the recessed surface 60a in the axial direction. In other words, the position of the connecting boundary line 51f in the axial direction lies within the area N1 where the recessed surface 60a is located, regardless of whether the needle 20 is fully raised or closed.

[0194] When the cup 50 moves axially while sliding on the guide element 60, the connection boundary line 51f is therefore opposite the recessed surface 60a and does not touch the sliding surface 61b. This prevents the cup 50 from being pressed against the guide element 60 in a state where the surface pressure component in the axial direction is large, and reduces wear on the cup 50. Consequently, the inclination of the cup 50, and therefore the inclination of the needle 20, can be reduced, thus minimizing the variation in the fuel injection quantity due to variations in the valve opening and closing timing of the needle 20.

[0195] Furthermore, in the fuel injection valve 1 according to the present embodiment, the surface 60a1 of the recessed surface 60a adjacent to the sliding surface 61b is shaped such that the gap CL1 between the fuel injection valve 1 and the cup 50 gradually increases in the radial direction with increasing distance or length from the sliding surface 61b. In this example, in contrast to the present embodiment, if the adjacent surface 60a1 has a shape in which the radial direction is increased in steps, the surface pressure is increased when the edge section of the stepped section is pressed against the cup 50 moving towards the nozzle opening side, and there is a concern that wear will be accelerated.Since the adjacent surface 60a1 has a shape that gradually expands in the radial direction according to the present embodiment, the aforementioned surface pressure can be mitigated and the fear of promoting wear between cup 50 and guide element 60 can be reduced.

[0196] Furthermore, in the fuel injection valve 1 according to the present embodiment, the adjacent surface 60a1 comprises the inclined surface 60a2, which extends linearly in the sectional view. The angle of inclination θ1 at which the inclined surface 60a2 is inclined relative to the sliding surface 61b is greater than the assumed maximum angle of inclination θ2 at which the cup 50 is inclined. For this reason, the possibility of the tilted cup 50 coming into contact with the inclined surface 60a2 can be reduced, and the risk of promoting wear between the cup 50 and the guide element 60 can be decreased.

[0197] Furthermore, in the fuel injection valve 1 according to the present embodiment, the limiting section 60b, including the boundary between the adjacent surface 60a1 and the sliding surface 61b, has a radially inwardly convex shape. In contrast to the present embodiment, in this example, if the edge section has a sharp shape, the surface pressure is increased when the edge section is pressed against the cup 50 moving towards the nozzle opening side, and there is a concern that wear will be promoted. Since the edge section 60b in the present embodiment has a radially inwardly curved shape, the surface pressure can be mitigated in light of the above-mentioned circumstances, and the concern about wear promotion is reduced.

[0198] Furthermore, in the fuel injection valve 1 according to the present embodiment, the guide element 60 is made of a magnetic material and the cup 50 of a non-magnetic material. According to the configuration described above, the parallel surface of the cup 50 is prevented from being pressed against the sliding surface 61b of the guide element 60 by the electromagnetic attraction force acting on the cup 50 in a radial direction. This reduces wear between the cup 50 and the guide element 60.

[0199] Furthermore, in the fuel injection valve 1 according to the present embodiment, the cup 50 and the guide element 60 have the same hardness. Generally, a non-magnetic material has a lower hardness than a magnetic material. However, in the present embodiment, as described above, a very hard non-magnetic material is used for the cup 50 instead of a general non-magnetic material. For this reason, the possibility of accelerated wear of the element on the side of lower hardness due to a difference in hardness is avoided, thus preventing the electromagnetic attraction force acting on the cup 50.

[0200] Furthermore, in the fuel injection valve 1 according to the present embodiment, the gap CL1 between the parallel surface of the cup 50 and the sliding surface 61b of the guide element 60 is larger than the gap CL2 between the cup 50 and the needle 20.

[0201] In this example, the needle 20 can be opened and closed in a tilted state relative to the direction of the axis line C. When the needle 20 is tilted, the cup 50 is tilted by a tilting force, and when the cup 50 is tilted, the force with which the cup 50 is pressed against the guide element 60 increases, which can lead to wear. Therefore, according to the present embodiment, in which the recessed surface 60a is used in a configuration where the wear described above is a concern, the wear-reducing effect of the recessed surface 60a can be more effectively utilized. <Detaillierte Beschreibung der Konfigurationsgruppe E>

[0202] Next, a configuration group E, comprising at least the press-fit structure between the outer core 31 and the inner core 32 and the configuration associated with the press-fit structure, is described in detail among the configurations of the fuel injector 1 according to the present embodiment with reference to the Fig. 38 and Fig. 39. Furthermore, a modification of configuration group E will be described later with reference to the Fig. Described in sections 40 to 42.

[0203] As in Fig. Figure 38 shows a press fit surface 31p, formed on the inner circumferential surface of the outer core 31, and a press fit surface 32p, formed on the outer circumferential surface of the inner core 32, which are press-fitted into one another. The press fit surfaces 31p and 32p are not formed over the entire area in the direction of the axis C, but only partially in the direction of the axis C.

[0204] In the present embodiment, the press fit surfaces 31p and 32p are formed on a portion of the movable core 30 on the side opposite the nozzle opening. In the following description, a section of the outer core 31 in which the press fit surface 31p is formed, and the entire section in the direction of the axis line C including the press fit surface 31p, is referred to as the press fit area 311. A section of the outer core 31 in which the press fit surface 31p is not formed, and the entire portion in the radial direction that does not include the press fit surface 31p, is referred to as the non-press fit area 312. In other words, in the direction of the axis line C, the outer core 31 is divided into a press fit area 311 on the side opposite the nozzle opening and a non-press fit area 312 on the side of the nozzle opening that adjoins the press fit area in the direction of the axis line C.

[0205] The non-press-fit area 312 is formed by a locking section 31b, which contacts a locking section 32i of the inner core 32 in the direction of the axis line C. The locking section 32i prevents the inner core 32 from being deflected towards the nozzle opening side relative to the outer core 31 by a collision of the inner core 32 with the guide element 60 and the like. In the inner circumferential surface of the non-press-fit area 312, a gap B3 is provided from the inner core 32 in a section extending from the locking section 31b to the boundary of the press-fit area 311. In other words, the gap B3 is located at the boundary between the press-fit area 311 and the non-press-fit area 312.

[0206] Gap B3 serves as a containment area for burrs that form during the press fit of the inner core 32 into the outer core 31. Since the material of the outer core 31 is softer than that of the inner core 32, the burrs are generated on the press-fit surface 31p of the outer core 31. More precisely, the aforementioned burrs are generated when the nozzle-opening end section of the press fit surface 32p of the inner core 32 scrapes away part of the press fit surface 31p of the outer core 31.

[0207] In the present embodiment, after the inner core 32 is assembled with the outer core 31, the communication grooves 32e and the outer communication grooves 31e are produced by cutting or similar means, and then the first core contact surface 32c and the second core contact surface 32b are ground. As a result, the positions of the first core contact surface 32c and the second core contact surface 32b are aligned in the axis line C.

[0208] The outer circumferential surface of the outer core 31, which in Fig. 39, indicated by a solid line, shows a state before press-fitting with the inner core 32 and is circular (perfect circle) in plan view. On the other hand, in the state after press-fitting with the inner core 32, the outer circumferential surface of the press-fit area 311 of the outer core 31 expands radially outwards, as shown by a dashed line in Fig. Figure 39 is shown. However, a section in which the through-holes 31a are present (small expansion section 331a or expansion section 311a) is less likely to expand than a section in which the through-holes 31a are not present (large expansion section 331b or expansion section 311b). Therefore, the outer circumferential surface of the press-fit area 311 after press-fitting is not a perfect circle, and the large expansion section 311b has a shape with a larger diameter than the small expansion section 311a. In the pre-press-fit state, the diameter of the outer circumferential surface of the press-fit area 311 is equal to the diameter of the non-press-fit area 312. Therefore, in the post-press-fit state, the outer circumferential surface of the press-fit area 311 has a larger diameter than the outer circumferential surface of the non-press-fit area 312 (see Figure 39). Fig. 38).

[0209] The holder for the movable reception of the movable core 30 has the main body 12, which is a magnetic element, and the non-magnetic element 14, which adjoins the main body 12 in the direction of movement. An end face of the main body 12 and an end face of the non-magnetic element 14 are welded together. A section of the holder facing the outer circumferential surface of the press-fit area 311 is defined as a section H1 facing the press-fit area, and a section of the holder facing the outer circumferential surface of the non-press-fit area 312 is defined as a section H2 facing the non-press-fit area.A minimum radial gap between the inner circumferential surface of section H1 facing the press fit section and the outer circumferential surface of the press fit area 311 is defined as a press fit section gap CL3, and a minimum radial gap between the inner circumferential surface of section H2 facing the non-press fit area and the outer circumferential surface of the non-press fit area 312 is defined as a non-press fit section gap CL4. A minimum inner diameter of section H1 facing the press fit section is set larger than a minimum inner diameter of section H2 facing the non-press fit area, such that the press fit section gap CL3 is larger than the non-press fit section gap CL4.

[0210] The inner circumferential surface of section H1 facing the press fit section has a shape that extends parallel to the direction of movement of the movable core 30 (in the direction of the axis line C). The inner circumferential surface of section H2 facing the non-press fit section has a parallel surface H2a extending parallel to the direction of movement and a connecting surface H2b that joins the inner circumferential surface of section H1 facing the press fit section and the parallel surface H2a. The connecting surface H2b has a shape in which the inner diameter gradually decreases towards the parallel surface H2a. Although part of the main body 12 is contained within section H2 facing the non-press fit section, the non-magnetic element 14 is not contained within section H2 facing the non-press fit section, and the parallel surface H2a and the connecting surface H2b are formed by the main body 12.In other words, the main body 12 has a shape in which the parallel surface H2a and the connecting surface H2b have different inner diameter dimensions. The non-press-fit section gap CL4, which is the smallest gap between the section H2 facing the non-press-fit area and the non-press-fit area 312, corresponds to a gap in the parallel surface H2a formed by the main body 12.

[0211] More precisely, a flow channel cross-sectional area defined by the press-fit section gap CL3 is larger than a flow channel cross-sectional area defined by the non-press-fit section gap CL4. These flow channel cross-sectional areas are surfaces with a cross-section perpendicular to the axis C of the flow channel, defined by the press-fit section gaps CL3 and CL4.

[0212] The inner circumferential surface H1a of the section H1 facing the press-fit section has a shape parallel to the direction of movement. The section H1 facing the press-fit section comprises a portion of the non-magnetic element 14 and a portion of the main body 12. The non-magnetic element 14 is shaped such that it has a uniform inner diameter dimension along its entire axis in the C direction. The gap of the press-fit section, or the press-fit section gap CL3, which is the smallest gap between the section H1 facing the press-fit section and the press-fit area 311, corresponds to a gap on a section of the main body 12 on the side opposite the nozzle opening with respect to the connecting surface H2b or on the non-magnetic element 14.

[0213] When the movable core 30, attracted by the fixed core 13, is configured by an interference fit of the inner core 32 for collision with the guide element 60 and the like, and of the outer core 31 for the magnetic circuit, the outer diameter of the outer core 31 is slightly enlarged by the pressing. As a result, the gap between the inner circumferential surface of the holder that accommodates the movable core 30 and the outer circumferential surface of the outer core 31 becomes small, and the flow resistance that the movable core 30 experiences from the fuel present in the gap becomes large. Since it is difficult to compensate for the amount by which the outer diameter expands due to the interference fit, a mechanical differential variation in the magnitude of the flow resistance occurs, leading to a change in the speed of movement of the movable core 30.As a result, there is a variation in the machine's response behavior to the valve opening, leading to a large variation in the injection quantity.

[0214] On the other hand, according to the present embodiment, the fuel injection valve 1 comprises the needle 20 (valve body), the fixed core 13, the movable core 30, the main body 12 (holder), the non-magnetic element 14 (holder), and the guide element 60 (stop element). The movable core 30 has a cylindrical shape and moves together with the needle 20 by magnetic attraction to open the nozzle openings 11a. The holder has a movable chamber 12a filled with fuel and receives the movable core 30 in the movable chamber 12a in a movable state. The guide element 60 contacts the movable core 30 and prevents it from moving away from the nozzle openings 11a. The movable core 30 has the inner core 32, which touches the guide element 60, and the outer core 31, which is press-fitted into the outer circumferential surface of the inner core 32.The outer core 31 has the press-fit area 311, which is press-fitted into the outer circumferential surface of the inner core 32 in the direction of movement of the movable core 30, and the non-press-fit area 312, which is not pressed into the outer circumferential surface of the inner core 32 and adjoins the press-fit area 311 in the direction of movement. Of the gaps or spaces between the inner circumferential surface of the holder and the outer circumferential surface of the movable core 30, the smallest gap CL3 in the press-fit area 311 is larger than the smallest gap CL4 in the non-press-fit area 312.

[0215] In this example, the flow resistance experienced by the movable core 30 from the fuel present in the gap between the outer circumferential surface of the outer core and the inner circumferential surface of the holder is strongly influenced by the smallest gap when the gap size changes according to the axial position. The gap CL3 in the press-fit area 311, in the gap between the inner circumferential surface of the holder and the outer circumferential surface of the movable cores, is larger than the gap CL4 in the non-press-fit area 312. Therefore, in contrast to the current embodiment, if the minimum gap CL3 in the press-fit area 311 is smaller than the minimum gap CL4 in the non-press-fit area 312, the flow resistance is strongly influenced by the gap CL3 in the press-fit area 311. As a result, there is a large variation in flow resistance between the machines.In contrast, according to the present embodiment, the minimum gap CL3 in the press-fit area 311 is larger than the minimum gap CL4 in the non-press-fit area 312. For this reason, the flow resistance through the gap CL3 in the press-fit areas 311 cannot be influenced, and the movement speed of the movable core 30 cannot be varied. This prevents variations in the machine differential in the valve opening behavior and thus reduces variations in the injection quantity.

[0216] Furthermore, in the fuel injection valve 1 according to the present embodiment, the inner circumferential surface H1a of the section H1 facing the press-fit section has a shape parallel to the direction of movement. The inner circumferential surface of the section H2 facing the non-press-fit area has a parallel surface H2a extending parallel to the direction of movement and a connecting surface H2b that connects the inner circumferential surface of the section H1 facing the press-fit section and the parallel surface H2a. The connecting surface H2b has a shape in which the inner diameter gradually decreases towards the parallel surface H2a.

[0217] A boundary between a section (large expansion section 311b) where the expansion is largely generated by press fits and a section (small expansion section 311a) where the expansion is hardly generated is gradually expanded. In view of the above circumstances, according to the present embodiment, the gap of the magnetic circuit formed by the section of the connecting surface H2b, whose inner diameter gradually decreases, can be made as small as possible. As in Fig. As shown in Figure 38, the connecting surface H2b can have an oblique shape in which the inner diameter changes linearly and gradually, a curved shape in which the inner diameter changes in a curved manner, or a stepped shape in which the inner diameter changes in steps.

[0218] Furthermore, according to the present embodiment, the holder in the fuel injection valve 1 has the main body 12 (magnetic element) with magnetism and the non-magnetic element 14 adjacent to the main body 12 in the direction of movement, and the end face of the main body 12 and the end face of the non-magnetic element 14 are welded together. This makes it possible to perform a step to increase or decrease the inner diameter of the holder and a step to remove a weld mark from the inner circumferential surface of the holder in a series of operations, thereby reducing the work required for increasing or decreasing the inner diameter of the holder.

[0219] Furthermore, in the fuel injection valve 1 according to the present embodiment, three or more through-openings 31a are provided in the outer core 31 at regular intervals in the circumferential direction. According to the above configuration, there are three or more locations at regular intervals in the axial direction where the flow resistance encountered by the moving core 30 from the fuel in the moving chamber 12a is low. For this reason, when the moving core 30 moves in the direction of the axis C, the change in the inclination direction of the moving core 30 relative to the axis C can be reduced. Since the behavior of the moving core 30 can be prevented from becoming unstable, the variation in the valve opening behavior can be further reduced. [Modification E1]

[0220] In the present case, in Fig. In the modification shown in Figure 40, the maximum outer diameter of the outer core 31 in the press fit area 311 is smaller than the maximum outer diameter of the outer core 31 in the non-press fit area 312.

[0221] In particular, the outer diameter of the press fit area 311 is shaped such that it is sufficiently smaller than the outer diameter of the non-press fit area 312 before press fitting, and the outer diameter of the press fit area 311 is shaped such that it remains smaller than the outer diameter of the non-press fit area 312 even after the press fit area 311 is expanded by the press fit. In short, in a pre-press fit state, the outer circumferential surface of the press fit area 311 is cut to create a recess section 311c, and the cutting depth of the recess section 311c is set so that the recess section 311c is retained even after expansion by the press fit. Furthermore, the inner diameter dimension of the section H2 facing the non-press fit area in the direction of axis C is the same as that of the section H1 facing the press fit area.

[0222] Since, as described above, the outer circumferential area of ​​the press fit area 311 is smaller than the area without a press fit 312, and the inner circumferential area of ​​the section H2 facing the non-press fit area is the same as that of the pressed-in, opposite section H1, the press fit section gap CL3 is larger than the non-press fit section gap CL4. For this reason, the same effects as in the fuel injector 1 are observed in the present modification. Fig. 39 shown. [Modification E2]

[0223] In the present modification, which is in Fig. As shown in Figure 41, the entire section H1 of the holder facing the press fit consists of the non-magnetic element 14, and the main body 12 is not included in the press-fit section H1. For example, the length of the press fit surfaces 31p and 32p in the direction of the axis line C is opposite the structure of Fig. 39 is shortened so that the entire section H1 facing the press-fit section consists of the non-magnetic element 14. Alternatively, compared to the structure in Fig. 39 the length of the non-magnetic element 14 is extended in the direction of the axis line C, so that the entire section H1 facing the press-fit section consists of the non-magnetic element 14. Since in the present modification the press-fit section gap CL3 is larger than the non-press-fit section gap CL4, the same effects as in the fuel injector 1 are also achieved in the present modification. Fig. 39 shown. [Modification E3]

[0224] In the present modification, which is in Fig. As shown in Figure 42, a section of the press-fit area 311, which is widened or extended in the radial direction by the pressing-in process, is removed, and the maximum outer diameter of the outer core 31 in the press-fit area 311 is formed so that it matches the maximum outer diameter of the outer core 31 in the non-press-fit area 312.

[0225] More precisely, in a state prior to press fitting with the inner core 32, the outer core 31, whose outer circumferential surface is circular in plan view (perfect circle), is prepared (preparation process) and press-fitted with the inner core 32 (press fitting process). Afterwards, the large expansion section 311b, expanded by the press fitting (see Fig. 39) cut after the press fit (cutting process), whereby the outer core 31 is shaped such that the outer circumferential surface becomes circular (a perfect circle) in plan view. The inner diameter dimensions of the section H1 facing the press fit section and the section H2 facing the non-press fit section are equal in the direction of the axis line C. Therefore, the press fit section gap CL3 and the non-press fit section gap CL4 are equal. Therefore, the present modification shows the same effects as that of Fig. 39. (Second embodiment)

[0226] While the valve closing force transmission element according to the first embodiment is formed by the cup 50, a valve closing force transmission element according to the present embodiment is formed by a first cup 501, a second cup 502 and a third spring element SP3 (see Fig. 43) formed, which are described below. With the exception of the configuration to be described below, the configuration of a fuel injector according to the present embodiment is the same as the configuration of the fuel injector according to the first embodiment.

[0227] The first cup 501 contacts a first spring element SP1 and a needle 20 and transmits an elastic valve closing force from the first spring element SP1 to the needle 20. In short, the first cup 501 has the same function as the circular plate section 52 of the cup 50 according to the first embodiment. The first cup 501 is designed with a through-opening 52a similar to that of the first embodiment.

[0228] The third spring element SP3 is an elastic element that is elastically deformed in the axial direction to exert an elastic force. One end of the third spring element SP3 contacts a contact surface 501a of the first cup 501, and the other end of the third spring element SP3 contacts a contact surface 502a of the second cup 502. As a result, the third spring element SP3 is clamped between the first cup 501 and the second cup 502 and is elastically deformed in the axial direction, exhibiting an elastic force due to this elastic deformation.

[0229] The second cup 502 contacts the movable core 30 during the valve closing process to push the movable core 30 towards the nozzle openings. In short, the second cup 502 has the same function as the cylindrical section 51 of cup 50 according to the first embodiment. The third spring element SP3 performs a function of transmitting a force in the axial direction between the first cup 501 and the second cup 502.

[0230] The needle 20 has a main body section 2001 and an enlarged diameter section 2002, or a section with an enlarged diameter 2002. A valve closing contact surface 21b is formed at one end of the main body section 2001 on the side opposite the nozzle openings. The valve closing contact surface 21b contacts a valve closing force transmission contact surface 52c of the valve closing force transmission element (first cup 501) in the same manner as in the first embodiment.

[0231] The section with the enlarged diameter 2002 is located closer to the side of the nozzle opening than the valve closing contact surface 21b and has a circular plate shape in which the diameter of the main body section 2001 is enlarged. A valve opening contact surface 21a is formed on a surface of the nozzle opening side of the enlarged diameter section 2002. The valve opening contact surface 21a contacts the first core contact surface 32c of the movable core 30 in the same way as in the first embodiment. The length of a gap between the valve opening contact surface 21a and the first core contact surface 32c in the direction of the axis line C in the valve-closing state corresponds to a gap L1 according to the first embodiment.

[0232] In the state immediately following the switching of the excitation of a coil 17 from OFF to ON, a magnetic attraction force acts on the movable core 30 to initiate its movement towards the valve opening side. Then, as the movable core 30 moves while the second cup 502 is pushed upwards, and the movement reaches the gap L1, the first core contact surface 32c of the movable core 30 collides with the valve opening contact surface 21a in the needle 20.

[0233] In the present embodiment, the guide element 60 is eliminated, and the movable core 30 contacts the fixed core 13, thereby regulating the valve opening process amount or stroke of the needle 20. When the movable core 30 collides with the needle 20 as described above, a gap is created between the fixed core 13 and the movable core 30, and the length of the gap in the direction of the axis line C corresponds to a stroke L2 of the first embodiment.

[0234] The elastic force of the first spring element SP1 also acts on the needle 20 until the moment of collision. After the collision, the movable core 30 continues to move due to the magnetic attraction, and when the amount of movement after the collision reaches a stroke L2, the movable core 30 collides with the fixed core 13 and ceases to move. A separation distance between the housing-side seat 11s and the valve body-side seat 20s in the direction of the axis line C at the moment the movement ceases corresponds to a full stroke of the needle 20 and is equal to the stroke L2 described above. (Third embodiment)

[0235] According to the first embodiment, the valve closing force transmission element (cup 50) has a cup shape with a cylindrical section 51 and a circular plate part 52. On the other hand, according to the present embodiment, a valve closing force transmission element has a circular plate shape configured by a circular plate section 52 in which the cylindrical section 51 is eliminated (see Fig. 44). With the exception of the configuration to be described below, the configuration of a fuel injector according to the present embodiment is the same as the configuration of the fuel injector according to the first embodiment.

[0236] In the first embodiment, a surface (core contact end surface 51a) of the valve closing force transmission element is formed in the cylindrical section 51, with which the contact surface (second core contact surface 32b) of the movable core 30 is in contact. On the other hand, in the present embodiment, a surface of the circular plate section 52 on the nozzle opening side functions as a core contact end surface 52e (see Fig. 44), which touches the movable core 30. (Other embodiments)

[0237] The disclosure contained herein is not limited to the combinations of components and / or elements shown in the embodiments. The disclosure may include additional sections or parts that may be added to the embodiments. The disclosure includes the omission of components and / or elements of the embodiments. The disclosure includes the exchange or combination of components and / or elements between one embodiment and another. For example, the fuel injector 1 according to the first embodiment includes all configuration groups A, B, C, D, and E, but may be a fuel injector with any combination of configuration groups A, B, C, D, and E.

[0238] In the first embodiment, the temporary press fit is performed once, as in Fig. Figure 6 shows that the load measurement can be performed for each temporary press fit by repeating the temporary press fit two or more times. According to the configuration above, the second setpoint load can be adjusted to the target value with high accuracy. Furthermore, since the load is measured at each multiple of temporary press fit operations, the elastic modulus of the second spring element SP2 can be measured, and the degree of press fit at that operation can be calculated with high accuracy.

[0239] At the in Fig. In the press fit procedure shown in Figure 6, the second settling load is measured in a state where the press fit process is stopped and the press fit is terminated, but the second settling force can be measured during the press fit. In other words, the press fit is performed while the second settling load is being measured, and the press fit is stopped and completed when the measured second settling load reaches the target value.

[0240] At the in Fig. In the press-fit process or pressing-in process shown in Figure 6, the second setting load is measured while the cup 50, in the state of contact with the needle, restricts the movement of the movable core 30; but the second setting load can be measured while the contact section 21 of the needle 20 restricts the movement of the movable core 30.

[0241] The in Fig. The communication grooves 32e shown in Figure 12 are provided on the third core contact surface 32d in addition to the first core contact surface 32c and the second core contact surface 32b, but cannot be provided on the third core contact surface 32d. Although the Fig. Since the communication grooves 32e shown in Figure 12 are provided over the entire area of ​​the first core contact surface 32c in the radial direction, it is sufficient that the communication grooves 32e are provided at least in a section of the first core contact surface 32c next to the second core contact surface 32b.

[0242] Although the in Fig. The outer communication grooves 31e shown in Figure 16 are arranged such that they are not in contact with the through-openings 31a, or the outer communication grooves 31e can be arranged such that they are in contact with the through-openings 31a. The Fig. The communication grooves 32g shown in Figure 19 are provided via the first core contact surface 32c, the second core contact surface 32b and the third core contact surface 32d, but cannot be provided on the third core contact surface 32d.

[0243] In the examples of Fig. 21, Fig. 22 and Fig. In 23, the communication grooves 32e are eliminated, and in place of the communication grooves 32e, the connecting openings 20c, the sliding surface communication grooves 20d, and the second sliding surface communication grooves 32h are provided. On the other hand, the fuel injector 1 can contain two or more of the communication grooves 32e, the connecting openings 20c, the sliding surface communication grooves 20d, and the second sliding surface communication grooves 32h.

[0244] Although in an example of Fig. 22 the sliding surface communication grooves 20d are provided in the needle 20, the sliding surface communication grooves can be in the transmission element-side sliding surface 51c (see Fig. 22) of the cup 50, on which the needle 20 slides, are provided. In an example of Fig. 23 the second sliding surface communication grooves 32h are formed in the inner core 32, but the second sliding surface communication groove can be provided in the surface of the needle 20 which slides with the inner core 32.

[0245] In one example of Fig.24 The main flow channels 20e for supplying the fuel to the valve closing contact surface 21b in the state of contact with the cup 50 are provided by the grooves provided in the needle 20, but can also be provided by the grooves provided in the cup 50. In particular, the supply flow channel can be provided by grooves in the core contact end surface 51a of the cylindrical section 51.

[0246] In the first embodiment, the movable section M is supported radially at two points on the needle 20, i.e., on the section facing the inner wall surface 11c of the nozzle opening body 11 (the needle tip portion) and the outer circumferential surface 51d of the cup 50. Alternatively, the movable section M can be supported radially at two points: on the outer circumferential surface of the movable core 30 and on the needle tip portion or section.

[0247] In the first embodiment, the inner core 32 is made of a non-magnetic material, but can be made of a magnetic material. If the inner core 32 is made of a magnetic material, it can be made of a weakly magnetic material that is less magnetic than the outer core 31. Likewise, the needle 20 and the guide element 60 can be made of a weakly magnetic material that is less magnetic than the outer core 31.

[0248] In the first embodiment, the cup 50 is inserted between the first spring element SP1 and the movable core 30 to create a core boost structure in which the movable core 30 contacts the needle 20 to initiate the valve opening process when the movable core 30 moves a predetermined distance. Alternatively, the cup 50 can be omitted, and a core boost structure can be used in which a third spring element, distinct from the first spring element SP1, is provided, and the movable core 30 is pressed towards the nozzle opening by this third spring element.

[0249] In the first embodiment, a non-magnetic element 14 is arranged between the solid core 13 and the main body 12 to prevent a magnetic short circuit between them. Instead of the non-magnetic element 14, a magnetic element with a magnetic choke section to prevent the magnetic short circuit can be arranged between the solid core 13 and the main body 12. Alternatively, the non-magnetic element 14 can be eliminated, and a magnetic choke section can be formed in the solid core 13 or in the main body 12 to prevent the magnetic short circuit.

[0250] The sleeve or socket 40 according to the first embodiment has a shape in which the connecting section 42 extends on the top of the bearing section 43 (on the side opposite the nozzle openings) and the cylindrical insertion section 41 extends on the top of the connecting part 42. Alternatively, the sleeve 40 can have a shape in which the connecting section 42 extends below the bearing section 43 (on the nozzle opening side) and the cylindrical insertion section 41 extends further below the connecting section 42. The sleeve 40 can also be a hollow, annular ring that extends in a ring shape around the needle 20. In this case, the upper surface of the ring supports the second spring element SP2, and the inner circumferential surface of the ring is press-fitted into the press-fit section 23.

[0251] The cup 50 according to the first embodiment has a cup shape with the circular plate section 52 and the cylindrical section 51. Alternatively, the cup 50 can have a flat plate shape. In this case, the upper surface (top) of the flat plate contacts the first spring element SP1 and the lower surface (bottom) of the flat plate contacts the movable core 30.

[0252] According to the first embodiment, the support element 18 has a cylindrical shape, but can have a C-shaped cross-sectional shape in which a slot extending in the direction of the axis line C is cylindrically formed.

[0253] The movable core 30 according to the first embodiment has a two-part structure, i.e., with an outer core 31 and an inner core 32. The inner core 32 is made of a material with a higher hardness than the outer core 31 and has a surface that contacts the cup 50 and the guide element 60, as well as a surface that slides with the needle 20. Alternatively, the movable core 30 can have a structure in which the inner core 32 is eliminated.

[0254] If the movable core 30 has the structure in which the inner core 32 is eliminated as described above, it is preferable that the contact surface of the movable core 30, which contacts the cup 50 and the guide element 60, and the sliding surface, which slides with the needle 20, are plated. A specific example of a coating applied to the contact surface is chromium. A specific example of a coating applied to the sliding surface is nickel-phosphorus.

[0255] The fuel injection valve 1 according to the first embodiment has a structure in which the movable core 30 comes into contact with the guide element 60 attached to the fixed core 13. Alternatively, the movable core 30 may contact the fixed core 13, with the guide element 60 being eliminated. In short, the inner core 32 may contact the guide element 60, or the inner core 32 may contact the fixed core 13, with the guide element 60 being eliminated. Furthermore, a structure can be used in which the movable core 30, with the inner core 32 eliminated, contacts the guide element 60, or a structure in which the movable core 30, with the inner core 32 eliminated, contacts the fixed core 13, with the guide element 60 being eliminated.

[0256] In the case where the movable core 30 has the structure in which the inner core 32 is eliminated as described above, the surface of the movable core 30 on the side opposite the nozzle opening, which touches the needle 20, corresponds to the first core contact surface 32c. Furthermore, in the structure in which the guide element 60 is eliminated as described above, the surface of the movable core 30, which touches the fixed core 13, corresponds to the third core contact surface 32d.

[0257] In the first embodiment, the communication grooves 32e are provided in the section of the inner core 32 that contacts the guide element 60. Conversely, in the design where the guide element 60 is eliminated as described above, the communication grooves 32e are provided in the section of the inner core 32 that contacts the fixed core 13. If the movable core 30 has the structure in which the inner core 32 is eliminated as described above, the communication grooves 32e are provided in the section of the movable core 30 that contacts the fixed core 13.

[0258] According to the first embodiment, the cup 50 slides in the direction of the axis line C while contacting the inner circumferential surface of the guide element 60. Alternatively, the cup 50 can be configured to move in the direction of the axis line C, thereby defining a predetermined gap with the inner circumferential surface of the guide element 60.

[0259] In the first embodiment, the inner circumferential surface of the second spring element SP2 is guided through the connecting section 42 of the sleeve 40. Alternatively, the outer circumferential surface of the second spring element SP2 can be guided through the outer core 31.

[0260] In the first embodiment, one end of the second spring element SP2 is supported by the movable core 30 and the other end of the second spring element SP2 by the sleeve 40 attached to the needle 20. Alternatively, the sleeve 40 can be eliminated, and the other end of the second spring element SP2 can be supported by the main body 12.

[0261] While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to these embodiments and constructions. Rather, the present disclosure is intended to cover various modifications and equivalent arrangements. Furthermore, the various elements shown in different combinations and configurations, which are exemplary, as well as other combinations and configurations that include additional, fewer, or only a single element, are also included in the basic concept and scope of the present disclosure.

Claims

[1] Fuel injector comprising: a valve body (20) that opens or closes a nozzle opening (11a) for injecting a fuel; a solid core (13) which generates a magnetic attraction force when a coil (17) is excited; a movable core (30) which is attracted by the fixed core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when the movable core is moved by a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element (SP1) that is elastically deformed by the valve opening process of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing process; and a valve closing force transmission element (50) which is movably arranged relative to the valve body and transmits the elastic valve closing force to the valve body by moving relative to the nozzle opening and contacting the valve body, wherein the movable core has a first core contact surface (32c) that touches the valve body at the predetermined distance at which the movable core is moved in the direction away from the nozzle opening, and a second core contact surface (32b) that touches the valve closing force transmission element when it moves in the direction away from the nozzle opening, the movable core, the valve closing force transmission element and the valve body form a fuel storage chamber (B1) in which the fuel is accumulated when the valve body closes the nozzle opening, the fuel storage chamber being surrounded by the movable core, the valve closing force transmission element and the valve body, the first core contact surface is located inside the fuel storage chamber, a section of the valve closing force transmission element that touches the second core contact surface, separates an interior of the fuel storage chamber from an exterior space, and the first core contact surface and the second core contact surface have a communication groove (32e, 32g) through which the interior of the fuel storage chamber is connected to the exterior. [2] Fuel injection valve according to claim 1, wherein The communication channel is one of several communication channels, and The majority of the communication grooves are arranged at regular intervals in a circumferential direction when viewed from a direction of movement of the movable core. [3] Fuel injection valve according to claim 2, wherein the movable core has a connecting groove (32f) which connects the majority of the communication grooves. [4] Fuel injector according to any one of claims 1 to 3, wherein the movable core comprises the following: a contact section (32) on which the first core contact surface and the second core contact surface are formed; and a core body section (31) which differs in material from the contact section and has a surface (31c) facing the solid core, and the core body section is located outside an area in which the communication grooves extend. [5] Fuel injection valve according to any one of claims 1 to 4, further comprising: a stopper element (60) that touches the movable core to limit the movement of the movable core in the direction away from the nozzle opening, wherein the movable core has a third core contact surface (32d) which touches the stopper element and is located outside the fuel storage chamber, and the first core contact surface, the second core contact surface and the third core contact surface have the communication groove. [6] Fuel injection valve according to one of claims 1 to 5, wherein the communication groove has a bottom wall surface (32e1) extending perpendicular to a direction of movement of the movable core and a vertical wall surface (32e2) extending from the bottom wall surface in the direction of movement. [7] Fuel injector comprising: a valve body (20) that opens or closes a nozzle opening (11a) for injecting a fuel; a solid core (13) which generates a magnetic attraction force when a coil (17) is excited; a movable core (30) which is attracted by the fixed core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when the movable core is moved by a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element (SP1) that is elastically deformed by the valve opening process of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing process; and a valve closing force transmission element (50) which is movably arranged relative to the valve body and transmits the elastic valve closing force to the valve body by moving relative to the nozzle opening and contacting the valve body, wherein the movable core, the valve closing force transmission element and the valve body form a fuel storage chamber (B1) in which the fuel is accumulated when the valve body closes the nozzle opening, the fuel storage chamber being surrounded by the movable core, the valve closing force transmission element and the valve body, the valve body has an internal passage (20a) inside the valve body through which the fuel flows to the nozzle opening, and the valve body has a connecting opening (20c) through which the fuel storage chamber communicates with the internal passage. [8] Fuel injector comprising: a valve body (20) that opens or closes a nozzle opening (11a) for injecting a fuel; a solid core (13) which generates a magnetic attraction force when a coil (17) is excited; a movable core (30) which is attracted by the fixed core and moved in a direction away from the nozzle opening, the movable core coming into contact with the valve body when the movable core is moved by a predetermined distance to cause the valve body to initiate a valve opening operation; a spring element (SP1) that is elastically deformed by the valve opening process of the valve body and exerts an elastic valve closing force that causes the valve body to perform a valve closing process; and a valve closing force transmission element (50) which is arranged to be displaceable relative to the valve body and which transmits the elastic valve closing force to the valve body by sliding in the direction of the nozzle opening and contacting the valve body, wherein the movable core, the valve closing force transmission element and the valve body form a fuel storage chamber (B1) in which fuel is accumulated when the valve body closes the nozzle opening, the fuel storage chamber being surrounded by the movable core, the valve closing force transmission element and the valve body, and the valve body has a sliding surface (21c) on the valve body side, on which the valve closing force transmission element slides, the valve closing force transmission element has a transmission element-side sliding surface (51c) on which the valve body slides, and the valve body-side sliding surface or the transmission element-side sliding surface has a sliding surface communication groove (20d) through which an interior of the fuel storage chamber communicates with an exterior space.

Images