Fuel injection device

Abstract

The present invention prevents armature bolt malfunction due to deposits originating from fuel. A pressure control valve (30) of a fuel injection device (10) has: an electromagnet (31) that generates an electromagnetic force; an armature plate (36) that is attracted by the electromagnetic force; an armature bolt (50) that is provided with, at one end in the axial direction, a valving element (41) that opens and closes a discharge hole (34) and is engaged with the armature plate (36); and an armature guide (37) having a sliding hole (37a) that slidably supports the armature bolt (50). The armature bolt (50) has one or a plurality of recesses (54, 55, 57) provided in a region extending from the inside to the outside of an opening (37aa) of the sliding hole (37a).

Description

[0001]

Document Name

[0002]

Title of the Invention

[0003]

Technical Field

[0004]

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[0005]

Background Art

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[0009]

Prior Art Documents

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Patent Documents

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[0012] [Patent Document 1] Japanese Unexamined Patent Publication No. 2017-110536

[0013] [Summary of the Invention]

[0014] [Problems that the invention aims to solve]

[0015] [〇 0 0 6] However, in the pressure control valve of Patent Document 1, the gap between the armature bolt and the sliding hole of the armature guide is narrow, and deposits caused by fuel may be generated. In particular, in fuel injection systems that use a bicarbonate fuel such as FAME (Fatty Acid Methyl Ester), deposits are more likely to be generated in the aforementioned narrow gap compared to fuel injection systems that use conventional fuels. If the amount of deposit buildup becomes large, it will create sliding resistance for the armature bolt, and there is a risk that the fuel injection system will not be able to supply the desired amount of fuel to the engine.

[0016] [〇 0 0 7] The present invention has been made in view of the above problems, and provides a fuel injection device that can prevent malfunction of the armature bolt and supply a desired amount of fuel to the engine, even when deposits caused by fuel occur around the armature bolt.

[0017] [Means for solving the problem]

[0018] [〇 0 0 8] In order to solve the above problems, according to one aspect of the present invention, a fuel injection device is provided comprising: a housing having a fuel injection hole formed at one end for injecting fuel; a nozzle needle provided inside the housing so as to be reciprocally movable and for opening and closing the fuel injection hole; a pressure control chamber formed inside the housing into which the fuel flows and generates pressure that pushes the nozzle needle toward the fuel injection hole; a discharge hole for discharging the fuel that has flowed into the pressure control chamber; and a pressure control valve for opening and closing the discharge hole, wherein the pressure control valve comprises an electromagnet for generating an electromagnetic force; an armature plate attracted by the electromagnetic force; an armature bolt engaged with the armature plate and having a valve body for opening and closing the discharge hole provided at one end in the axial direction; and an armature guide having a sliding hole for slidably supporting the armature bolt, wherein the armature bolt has one or more recesses provided in a region extending inside and outside the opening of the sliding hole.

[0019] [Effects of the Invention]

[0020] [0 0 0 9] As described above, according to the present invention, even if deposits caused by fuel occur around the armature bolt, malfunction of the armature bolt can be prevented and the desired amount of fuel injection can be supplied to the engine.

[0021] [Brief explanation of the drawing]

[0022] [ 0 0 1 0 ]

[0023] [Figure 1] A schematic diagram showing an example of the basic configuration of a fuel injection system according to an embodiment of the present disclosure.

[0024] [Figure 2] This is a partial cross-sectional view showing the configuration of a pressure control valve in a fuel injection system according to an embodiment of the present disclosure.

[0025] [Figure 3] This is an explanatory diagram showing a first example of an armature bolt of a pressure control valve of a fuel injection system according to the same embodiment.

[0026] [Figure 4] This is an explanatory diagram showing a second example of an armature bolt of a pressure control valve of a fuel injection system according to the same embodiment.

[0027] [Figure 5] This is a cross-sectional view of the armature bolt shown in Figure 4.

[0028] [Figure 6] This is an explanatory diagram showing a third example of an armature bolt of a pressure control valve of a fuel injection system according to the same embodiment.

[0029] [Figure 7] This is an explanatory diagram showing a third example of a modified armature bolt of the pressure control valve of the fuel injection system according to the same embodiment.

[0030] [Modes for carrying out the invention]

[0031] [0 0 1 1] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numeral, and redundant explanations will be omitted. Also, in the following description, the directions up, down, left, and right refer to the directions up, down, left, and right as shown in the figures.

[0032] [0 0 1 2] Fuel Injection System > First, an example of the configuration of a fuel injection system according to an embodiment of the present disclosure will be described.

[0033] [0 0 1 3] Figure 1 shows a cross-sectional view of fuel injection device 1. The illustrated fuel injection device 1 is, for example, provided in a fuel injection system equipped with a common rail, and injects fuel into the cylinders of an internal combustion engine, which is distributed by a common rail that stores the fuel pumped from the fuel supply pump.

[0034] [0 0 1 4] The fuel injection system 1 comprises an injector housing 11, a nozzle body 13, a nozzle nut 14, a nozzle needle 19, a piston 23, and a holder 25. The nozzle body 13 is attached to the front end of the injector housing 11 using the nozzle nut 14. The holder 25 is attached to the rear end of the injector housing 11 by press-fitting or screwing.

[0035] [0 0 1 5] The injector housing 11 has a hole extending in the axial direction, and a piston 23 is arranged in the hole so as to be able to reciprocate. The nozzle body 13 has a hole extending in the axial direction, and a nozzle needle 19 is arranged in the hole so as to be able to reciprocate. A fuel injection hole 12 is formed at the tip (lower end) of the hole. The hole in the injector housing 11 and the hole in the nozzle body 13 are provided coaxially. Between the piston 23 and the nozzle needle 19, an intermediate member 21 is arranged in contact with the piston 23 and the nozzle needle 19, respectively. The intermediate member 21 is constantly biased toward the nozzle needle 19 by the biasing force of a spring 22, biasing the nozzle needle 19 toward the fuel injection hole 12 (valve closing direction).

[0036] [0 0 1 6] The fuel injector 1 has a first fuel passage 15 and a second fuel passage 16 through which high-pressure fuel distributed from the common rail via an inlet body (not shown) passes. The high-pressure fuel flowing through the first fuel passage 15 is introduced into a gallery provided in the middle of the hole in the nozzle body 13. The pressure of the high-pressure fuel introduced into the gallery biases the nozzle needle 19 toward the rear end (in the valve opening direction). The high-pressure fuel flowing through the second fuel passage 16 is introduced into a pressure control chamber 17 formed on the rear end side of the piston 23. The pressure of the high-pressure fuel introduced into the pressure control chamber 17 biases the piston 23 toward the tip (in the valve closing direction).

[0037] [0 0 1 7] The fuel injection device 1〇 is equipped with a pressure control valve 3〇 that discharges high-pressure fuel from the pressure control chamber 17. When the sum of the pressure in the pressure control chamber 17 and the biasing force of the spring 22 exceeds the pressure in a gallery (not shown), the fuel injection hole 12 is closed by the nozzle needle 19. On the other hand, when high-pressure fuel is discharged from the pressure control chamber 17 and the pressure in the pressure control chamber 17 decreases, and the sum of the pressure in the pressure control chamber 17 and the biasing force of the spring 22 falls below the pressure in a gallery (not shown), the nozzle needle 19 retracts and the fuel injection hole 12 opens and fuel injection is performed.

[0038] [0 0 1 8] The operation of the fuel injector 1 is controlled by a control device based on rail pressure and target injection amount. The control device controls fuel injection by opening the pressure control valve 30 to discharge fuel from the pressure control chamber 17. The discharged fuel is discharged to the return piping via a connector (not shown) connected to the holder 25 and returns to a fuel tank (not shown).

[0039] [ 0 0 1 9 ]

[0040] <Pressure Control Valve> Figure 2 is a partial cross-sectional view showing a detailed example of the configuration of a pressure control valve 30. In Figure 2, the armature bolt 50 is shown in a side view, and the others are shown in a cross-sectional view.

[0041] [0 0 2 0] The pressure control valve 30 is a solenoid valve that opens and closes a discharge port 34 that communicates with the pressure control chamber 17. The pressure control valve 30 comprises an electromagnet 31, an armature plate 36, an armature bolt 50, an armature guide 37, a first spring 39, and a second spring 38. The armature bolt 50 is inserted into the armature plate 36 and engaged by a retaining plate b42 that fits into an engagement groove 51. The armature bolt 50 is inserted into the armature guide 37. The first spring 39 provides a biasing force to the armature bolt 50 toward the pressure control chamber 17. The second spring 38 applies a biasing force to the electromagnet 31 side relative to the armature plate 36.

[0042] [0 0 2 1] The pressure control valve 30 also includes a holder 25 in which a fuel return channel 28 for returning fuel to a fuel tank (not shown) is formed. The holder 25 and the electromagnet 31 are integrated within the electromagnet housing 32 and fastened to the joint with the injector housing 11 by a nut 33. Part of the internal space of the electromagnet housing 32 forms an armature chamber 32a in which an armature plate 36 is placed.

[0043]

[0022] When a driving current is supplied to the electromagnet 31 from a control circuit (not shown), an electromagnetic force is generated to attract the armature plate 36. The armature bolt 50 has a head portion 52 that engages with the armature plate 36 on the rear end side (holder 25 side). Further, the armature bolt 50 includes a valve holder 40 on the tip side (pressure control chamber 17 side). The valve holder 40 holds a valve body 41 that opens and closes the discharge hole 34. Also, the armature bolt 50 has a flange portion 53 erected in a direction perpendicular to the central axis of the armature bolt 50 on the tip side. The upper surface portion of the flange portion 53 (the main surface portion on the head portion 52 side in the flange portion 53) contacts the end surface of the armature guide 37 to limit the sliding range.

[0044]

[0023] The armature guide 37 is a cylindrical body having an axially extending sliding hole 37a. The armature bolt 50 is inserted into the sliding hole 37a so as to be slidable in the axial direction. The armature guides 37 are all positioned by ring-shaped spacers 43 and fixing bolts 35 and fixed to the injector housing 11. The armature guide 37 contacts the flange portion 53 of the armature bolt 50 at the lower end surface. The size of the gap between the upper end of the armature guide 37 and the lower end of the armature plate 36 is designed as a narrow gap of about 20 μm, for example. The armature guide 37 has a plurality of holes 37b for flowing the fuel discharged from the discharge hole 34 to the fuel reflux path 28.

[0045]

[0024] The first spring 39 is provided in a compressed state between the rear end portion of the armature bolt 50 and the holder 25, and biases the armature bolt 50 toward the valve body 41 side from the head portion 52. The second spring 38 is provided in a compressed state between the armature plate 36 and the armature guide 37, and biases the armature plate 36 toward the electromagnet 31 side.

[0046]

[0025] When high-pressure fuel is supplied to the pressure control chamber 17 and the valve body 41 blocks the discharge hole 34, the nozzle needle 19 closes the fuel injection hole 12 due to the pressure in the pressure control chamber 17 received via the piston 23 and the biasing force of the spring 22 (see Fig. 1).

[0047]

[0026] On the other hand, when the electromagnet 3I of the pressure control valve 3〇 is excited and the armature plate 36 is attracted to the electromagnet 31 side, the armature bolt 50 is also pulled up. Along with this, the valve body 41 is lifted by the pressure in the pressure control chamber 17 to open the discharge hole 34, and the high-pressure fuel in the pressure control chamber 17 is released to the pressure control valve 3〇 side through the discharge hole 34. As a result, the pressure inside the pressure control chamber 17 decreases, the piston 23 and the nozzle needle 19 move to the rear end side, the fuel injection hole 12 is opened, and fuel injection is performed.

[0048]

[0027] Further, when the power supply to the electromagnet 3! of the pressure control valve 3〇 is stopped, the attracting force of the electromagnet 31 on the armature plate 36 decreases. As a result, the armature bolt 50 is returned to the discharge hole 34 side by the first spring 39, and the valve body 41 closes the discharge hole 34. When the discharge hole 34 is closed, fuel pressure acts on the piston 23 in the pressure control chamber 17, and the piston 23 and the nozzle needle 19 move to the front end side. As a result, the fuel injection hole 12 is closed, and the fuel injection ends.

[0049] [0 0 2 8] When the pressure control valve 3〇 operates, the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 50 slide against each other, deposits caused by fuel may be generated on the sliding surface. For example, low-pressure fuel enters the sliding surface through the gap between the inner surface of the sliding hole 37a of the armature guide 37, located on the flange portion 53 side of the armature bolt 50, and the outer surface of the armature bolt 5〇. The gap between the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 5〇 is an extremely narrow gap, for example, designed to be about 2 m or less, and is not designed to forcibly enter this gap for lubrication. Therefore, there is almost no pressure gradient in the gap, making it difficult for fuel to enter or exit the gap, and causing the fuel present in the gap to accumulate.

[0050] [0 0 2 9] If fuel that has entered the gap remains, deposits may be generated depending on the components of the fuel and the temperature conditions. For example, in fuel injection systems that use biofuels, deposits are more likely to be generated on the sliding surface compared to fuel injection systems that use ordinary fuels. A portion of the deposit generated on the sliding surface moves toward the opening 37aa on the upper end side of the sliding hole 37a and gradually accumulates. The generated deposit can accumulate to a thickness of, for example, about 2〃 m, which corresponds to the size of the gap between the inner circumferential surface of the sliding hole 37a of the armature guide 37 and the outer circumferential surface of the armature bolt 5〇. If the amount of accumulated deposit increases, it becomes a sliding resistance of the armature bolt 50, causing a response delay in the pressure control valve 30. If there is a delay in the response of the pressure control valve 30, the operation of the nozzle needle 19 will also be delayed, which may prevent the fuel injector 10 from injecting the desired amount of fuel at the desired timing.

[0051] [0 0 3 0] In contrast, the fuel injection device 10 according to this embodiment has one or more recesses 54 in the armature bolt 50. As a result, the fuel injection device 10 reduces the area or axial distance in which fuel can accumulate in the gap between the inner circumferential surface of the sliding hole 37a of the armature guide 37 and the outer circumferential surface of the armature bolt 50, and has a configuration that makes it easier for fuel that has entered the gap to flow out into the armature chamber 32a.

[0052] [0 0 3 1] Armature bolt > Next, we will explain an example of the configuration of the armature bolt 5 0 of the pressure control valve 3.

[0053] [ 0 0 3 2 ]

[0054] (First Example) Figure 3 is an explanatory diagram showing a first example of an armature bolt 50. In Figure 3, the armature bolt 50 is shown in a side view, and the retaining plate 42, armature plate 36, and armature guide 37 are shown in a cross-sectional view. Note that in Figure 3, the distance between the lower end of the armature plate 36 and the upper end of the armature guide 37 is shown enlarged to facilitate understanding of this disclosure.

[0055] [0 0 3 3] The armature bolt 50 has an engagement groove 51, a head portion 52, a flange portion 53, and a recess 54. The recess 54 is provided in the region between the engagement groove 51 and the flange portion 53 along the axial direction. The recess 54 is provided in the region extending inside and outside the opening 37aa, which is located on the armature plate 36 side of the sliding hole 37a of the armature guide 37, of which openings 37aa and 37ab are located at both ends.

[0056] [ 0 0 3 4 ]

[0057] "The recess is provided in a region extending both inside and outside the opening" means that, when one or more recesses are viewed as a single unit, one end of the recess is located outside the opening and the other end is located inside the opening, i.e., within the sliding hole, in the direction along the axial direction of the armature bolt.

[0058] [0 0 3 5] In the first example, the recess 54 is formed as a small-diameter portion 55 which is a smaller diameter portion of a part of the armature bolt 50. The end 54a of the recess 54 on the head portion 52 side is located outside the opening 37aa of the armature guide 37, and the end 54b of the recess 54 on the flange portion 53 side is located inside the sliding hole 37a of the armature guide 37. The recess 54, consisting of the small-diameter portion 55, forms a continuous space extending both inside and outside the opening 37aa of the sliding hole 37a of the armature guide 37.

[0059] [0 0 3 6] As a result, fuel that has entered the gap between the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 50 moves toward the opening 37aa on the upper end side of the sliding hole 37a and can flow out into the recess 54. The fuel that has flowed out into the recess 54 flows out into the armature chamber 32a through the gap between the armature plate 36 and the armature guide 37. Therefore, it is possible to suppress the accumulation of fuel flow and the formation of deposits.

[0060] [0 0 3 7] Furthermore, even if deposits are generated on the sliding surface between the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 50, fuel flows from the gap between the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 50 to the armature chamber 32a, thereby suppressing the adhesion of deposits to the sliding surface between the inner surface of the sliding hole 37a of the armature guide 37 and the outer surface of the armature bolt 50. Therefore, malfunction of the armature bolt can be prevented and the desired amount of fuel injection can be supplied to the engine.

[0061] [0 0 3 8] The area in which the recess 5 4 is provided may be designed to cover the area in which deposits are expected to adhere, based on actual equipment or simulations. By reducing the diameter of the entire area in which deposits are expected to adhere, the certainty of suppressing deposit adhesion can be increased. The depth of the recess 5 4 may be designed such that the sum of the design value of the gap between the inner circumferential surface of the sliding hole 3 7 a of the armature guide 3 7 and the outer circumferential surface of the armature bolt 5 0 and the depth of the recess 5 4 is greater than or equal to the diameter of the deposit. This makes it less likely for deposits to accumulate in the gap between the inner circumferential surface of the sliding hole 3 7 a of the armature guide 3 7 and the outer circumferential surface of the armature bolt 5 0, and allows the deposits to flow out into the armature chamber 3 2 a.

[0062] [0 0 3 9] In addition, in the first example, since the recess 54 is formed as a single small-diameter portion 55, it is easy to process in manufacturing and can suppress an increase in production costs.

[0063] [ 0 0 4 0 ]

[0064] (Second example) In contrast to the first example where it was formed as a single small-diameter portion 5 5, in the second example the recess 5 4 has a plurality of axial grooves 5 6 provided both inside and outside the opening 37aa of the sliding hole 37a along the axial direction of the armature bolt 5 0.

[0065] [0 0 4 2] In the second example as well, the recess 54 is provided in the region extending inside and outside the opening 37aa, which is located on the armature plate 36 side of the openings 37aa and 37ab at both ends of the sliding hole 37a of the armature guide 37. In addition, each axial groove 56 forms a continuous space extending inside and outside the opening 37aa of the sliding hole 37a of the armature guide 37.

[0066] [0 0 4 3] This allows the same effect as in the first example to be obtained in the second example as well. In addition, in the second example, multiple axial grooves 5 6 with a depth greater than the expected thickness of the deposit are provided throughout the entire area where the deposit is expected to adhere, thus the armature bolt

[0067] This method can suppress an increase in the sliding resistance of the armature bolt 50 without excessively reducing its strength, even when deposits are present.

[0068] [0 0 4 4] In the second example, since the recess 54 is composed of multiple axial grooves 56, there is a degree of freedom in the combination of the width and number of each axial groove 56, making it possible to design a system that ensures the strength of the armature bolt 50 and suppresses the increase in the sliding resistance of the armature bolt 50.

[0069] [ 0 0 4 5 ]

[0070] (Third Example) Figure 6 is an explanatory diagram showing a third example of the armature bolt 50. Figure 6 is an explanatory diagram corresponding to Figure 3 above, in which the armature bolt 50 is shown in a side view, and the retaining plate 42, armature plate 36, and armature guide 37 are shown in a cross-sectional view.

[0071] [0 0 4 6] In the first example, the recess 54 was formed as a single small-diameter portion 55 in which the diameter of a part of the armature bolt 50 was reduced, whereas in the third example, the recess 54 has a plurality of circumferential grooves 57 arranged in the axial direction of the armature bolt 50, both inside and outside the opening 37aa of the sliding hole 37a.

[0072] [0 0 4 7] In the third example, the circumferential groove 57 located furthest towards the head portion 52 is located outside the opening 37aa of the armature guide 37, and the circumferential groove 57 located furthest towards the flange portion 53 is located inside the sliding hole 37a of the armature guide 37. By forming a recess 54 with such multiple circumferential grooves 57, fuel can be intentionally allowed to stagnate in each circumferential groove 57, and even if deposits are formed, the deposits can be retained inside the circumferential groove 57. Therefore, it is possible to suppress the adhesion of deposits to the sliding surface between the inner circumferential surface of the sliding hole 37a of the armature guide 37 and the outer circumferential surface of the armature bolt 5〇. Therefore, malfunctions of the armature bolt can be prevented, and the desired amount of fuel injection can be supplied to the engine.

[0073] [0 0 4 8] In addition, in the third example, the recess 54 consists of multiple circumferential grooves 57, which makes it easy to manufacture and suppresses an increase in production costs.

[0074] [ 0 0 4 9 ]

[0075] (Other variations) In the first example above, the small diameter portion 5 5 was formed with a uniform diameter, but the small diameter portion 5 5 may have a tapered shape or a shape with an uneven diameter.

[0076] [0 0 5 0] In the second example above, the axial groove 56 was formed along the axial direction of the armature bolt 50, but the axial groove may be formed along a direction inclined with respect to the axial direction of the armature bolt 50. Even in this configuration, each axial groove has a continuous space extending both inside and outside the opening 37aa of the sliding hole 37a, so that fuel that has entered the gap between the outer surface of the armature bolt 50 and the sliding hole 37a of the armature guide 37, or deposits generated in the gap, can be drained into the armature chamber 32a.

[0077] [0 0 5 1] In addition, in the third example above, the circumferential groove 57 was formed on a surface perpendicular to the axial direction of the armature bolt 50, but the circumferential groove may be formed on a surface that intersects with the axial direction of the armature bolt 50 at a predetermined angle. Even in this configuration, fuel can be intentionally allowed to stagnate in each circumferential groove, and even if deposits are formed, the deposits can be retained inside the circumferential grooves. Therefore, it is possible to suppress the adhesion of deposits to the sliding surface between the inner circumferential surface of the sliding hole 37a of the armature guide 37 and the outer circumferential surface of the armature bolt 50.

[0078] [0 0 5 2] In addition, in the third example above, the circumferential groove 5 7 had a rectangular cross-section, but the cross-section of the circumferential groove 5 7 is not limited to a rectangle. Figure 7 shows an example of a circumferential groove having a triangular cross-section. The illustrated circumferential groove 5 7 has a shape in which the deepest part in the depth direction of the groove is located below the opening of the circumferential groove 5 7. With a circumferential groove 5 7 of this shape, deposits accumulated inside the circumferential groove can be retained so as not to flow out of the circumferential groove 5 7. Therefore, it is possible to suppress the adhesion of deposits to the sliding surface between the inner circumferential surface of the sliding hole 37a of the armature guide 3 7 and the outer circumferential surface of the armature bolt b 5 0.

[0079] [0 0 5 3] In addition, in the above embodiment, a recess 5 4 was provided in the region extending inside and outside the opening 37aa on the armature plate 36 side of the sliding hole 37a of the armature guide 37, but instead of the region extending inside and outside the opening 37aa on the armature plate 36 side, or in combination with the region extending inside and outside the opening 37aa on the armature plate 36 side, a recess may be provided in the region extending inside and outside the other opening 37ab. In this case, when the valve body 4 1 provided at the lower end of the armature bolt 50 closes the discharge hole 3 4, and the flange portion 5 3 of the armature bolt 50 is spaced apart from the end face of the armature guide 3 7, a recess is provided in the area extending both inside and outside the opening 3 7 ab.

[0080] [0 0 5 4] As a result, repeated contact and separation between the flange portion 53 of the armature bolt 50 and the end face of the armature guide 37 allows fuel that has entered the gap between the outer surface of the armature bolt 50 and the sliding hole 37a of the armature guide 37 to flow out to the flange portion 53, thereby suppressing the adhesion of deposits to the sliding surface between the outer surface of the armature bolt 50 and the sliding hole 37a of the armature guide 37.

[0081] [0 0 5 5] Although preferred embodiments of the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to such examples. It is clear to any person with ordinary skill in the art to which the present invention belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these are also understood to be within the technical scope of the present invention.

[0082] [Explanation of symbols]

[0083] [ 0 0 5 6 ]

[0084] 1 〇:Fuel injection device

[0085] 1 1: Injector Housing

[0086] 1 2 :Fuel injection hole

[0087] 17: Pressure Control Room

[0088] 1 9: Nozzle Needle

[0089] 2 3: Piston

[0090] 3 ○: Pressure control valve

[0091] 3 1: Electromagnet

[0092] 3 2 a: Armature chamber

[0093] 3 4 :Drain hole

[0094] 3 6: Armature Plate

[0095] 3 7: Armature Guide

[0096] 3 7 a:Sliding hole

[0097] 3 7 aa: Opening S

[0098] 3 7 ab: Opening S

[0099] 4 1: Valve body

[0100] 5 ○: Armature Bolt

[0101] 5 4: Recess

[0102] 5 5: Small diameter part

[0103] 5 6: Axial direction groove

[0104] 5 7 : Zhou Fangxiang Ditch

Claims

[Document Name] Scope of Claim

1. An injector housing (11) having a fuel injection hole (12) formed at one end for injecting fuel; a nozzle needle (19) provided reciprocally within the injector housing (11) for opening and closing the fuel injection hole (12); a pressure control chamber (17) formed within the injector housing (11) for which the fuel flows in and generates pressure to push the nozzle needle (19) toward the fuel injection hole (12); a discharge hole (34) for discharging the fuel that has flowed into the pressure control chamber (17); and a pressure control valve (30) for opening and closing the discharge hole (34), wherein the pressure control valve (30) comprises an electromagnet (31) for generating an electromagnetic force, an armature plate (36) attracted by the electromagnetic force, and the armature plate (36) A fuel injection device comprising: an armature bolt (50) engaged with and having a valve body (41) for opening and closing the discharge hole (34) provided at one end in the axial direction; and an armature guide (37) having a sliding hole (37a) for slidably supporting the armature bolt (50), wherein the armature bolt (50) has one or more recesses (54, 55, 57) provided in a region extending inside and outside the opening (37aa) of the sliding hole (37a).

2. The fuel injection device according to Claim 1, characterized in that the one or more recesses (54) have a continuous space extending inside and outside the opening (37 aa) of the sliding hole (37 a).

3. The fuel injection device according to claim 2, characterized in that the one or more recesses (54) are a single small-diameter portion (55) provided both inside and outside the opening (37 aa) of the sliding hole (37 a).

4. The fuel injection device according to claim 2, characterized in that the one or more recesses (54) are a plurality of axial grooves (56) provided in and out of the opening (37 aa) of the sliding hole (37 a) along the axial direction of the armature bolt (50).

5. The fuel injection device according to Claim 1, characterized in that the one or more recesses (54) are a plurality of circumferential grooves (57) arranged in a region extending inside and outside the opening (37 aa) of the sliding hole (37 a) along the axial direction of the armature bolt (50).

6. The fuel injection device according to claim 1, characterized in that the one or more recesses (57) are provided in a region extending inside and outside the opening (37aa) of the sliding hole (37a) that is located on the armature plate (36) side. 9

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