Fuel injection valve

Abstract

The invention provides a fuel injection valve which suppresses fuel injection performance deviation caused by strain of an orifice. A fuel injection valve is provided with a fuel passage (1) into which fuel is introduced, and an orifice member (3) press-fitted into the inner wall of the fuel passage (1). The orifice member (3) is provided with: a cylindrical section (6) fixed to the inner wall of the fuel passage (1) by press fitting; an end wall part (7) which covers one end of the cylindrical part (6) and is provided with an orifice (2); and an annular stress absorbing section (8) that is interposed between one end of the cylindrical section (6) and the outer periphery of the end wall section (6) and that absorbs stress caused by the press-fitting.

Description

Technical Field

[0001] The present invention relates to a fuel injection valve provided with an orifice component, wherein the orifice component has an orifice in a fuel passage. Background Art

[0002] Conventionally, there is known a fuel injection valve having a throttle hole component, wherein a throttle hole is provided in a fuel passage inside a housing of the throttle hole component (for example, see Patent Document 1). The fuel injection valve is provided with a fuel inlet tube connected to a fuel distribution cap, the fuel distribution cap is branched from a fuel rail pipe connected to a discharge port of a fuel pump, and the throttle hole component is installed at the inlet of the fuel inlet tube.

[0003] The throttle hole component is composed of a cylindrical mounting tube and a metal diaphragm provided in a manner covering the upstream end of the mounting tube. A throttle hole is provided in the center of the metal diaphragm. A cylindrical fitting recess and an annular step portion connected to the downstream end are formed on the inner circumferential surface of the inlet portion of the fuel inlet tube connected to the fuel distribution cover.

[0004] The mounting flange of the fuel filter is placed on the annular step portion, and the fuel filter is mounted. Thereafter, the mounting cylinder portion of the orifice component is pressed into the fitting recess of the fuel inlet cylinder so that the downstream end of the mounting cylinder portion is closely attached to the flange of the fuel filter, thereby mounting the orifice component on the fuel inlet cylinder.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-139378 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the fuel injection valve of the above-mentioned Patent Document 1, the orifice component is mounted on the fuel inlet barrel by pressing the mounting cylinder of the orifice component into the fitting recess of the fuel inlet barrel. Therefore, the orifice component is deformed by the compressive force applied to the mounting cylinder during the press-in operation, and the deformation is transmitted to the orifice, which may cause strain in the orifice. The strain may cause deviation in the fuel injection performance of the fuel injection valve.

[0010] In view of the above-mentioned problems in the prior art, an object of the present invention is to provide a fuel injection valve that suppresses the variation in fuel injection performance caused by the strain of the orifice.

[0011] Means for solving problems

[0012] The fuel injection valve of the present invention comprises a fuel passage and a throttle hole component, wherein the fuel passage is for introducing injected fuel, and the throttle hole component has a throttle hole and is pressed into the inner wall of the fuel passage. The fuel injection valve is characterized in that the throttle hole component comprises: a cylindrical portion, which is fixed to the inner wall by the pressing; an end wall portion, which covers one end of the cylindrical portion and is provided with the throttle hole; and an annular stress absorbing portion, which is located between the one end of the cylindrical portion and the outer periphery of the end wall portion, and absorbs the stress caused by the pressing.

[0013] According to the present invention, the cylindrical portion of the throttle hole component pressed into the inner wall of the fuel passage has strain caused by the stress received from the inner wall when pressed. However, the strain is absorbed by the annular stress absorbing portion between the cylindrical portion and the end wall portion, and the strain is suppressed from being transmitted from the end wall portion to the throttle hole. Therefore, the throttle hole can maintain the designed size as much as possible, thereby providing a fuel injection valve that suppresses the deviation of fuel injection performance.

[0014] In the present invention, the annular stress absorbing portion may be connected to the one end of the cylindrical portion and the end wall portion via a curved portion, respectively. Thus, the stress during press-in can be controlled by the curved portion to be transferred from the cylindrical portion to the annular stress absorbing portion, and further from the annular stress absorbing portion to the end wall portion, thereby suppressing stress concentration at both end edges of the annular stress absorbing portion. Therefore, combined with the stress absorption effect of the annular stress absorbing portion, strain of the orifice can be more effectively avoided.

[0015] In the present invention, the end wall portion may be located on the downstream side of the cylindrical portion, and the throttle member may also include a flange portion extending radially outward from the upstream end of the cylindrical portion. Thus, when the throttle member is pressed into the fuel passage, the position of the throttle member can be easily confirmed by making the flange portion contact with the opening of the fuel passage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view showing an orifice member of a fuel injection valve according to a first embodiment of the present invention.

[0017] Figure 2 It means forming Figure 1 Schematic diagram of the situation of the throttle orifice component.

[0018] Figure 3 In Figure 3 A~3C means Figure 1 Schematic diagram of a situation in which a throttle hole component is pressed into a fuel inlet cylinder of a fuel injection valve.

[0019] Figure 4 In Figure 4A to 4C are schematic diagrams showing a state where a conventional orifice member having no annular stress absorbing portion is press-fitted into a fuel inlet tube portion of a fuel injection valve.

[0020] Figure 5 It means that Figure 1 A graph showing the measured results of the relationship between the interference [μm] when the orifice component is press-fitted into the fuel inlet cylinder of the fuel injection valve and the deformation amount (diameter change [μm]) of the orifice.

[0021] Figure 6 It means that Figure 1 A graph showing the measured results of the relationship between the interference [μm] when the orifice component is press-fitted into the fuel inlet cylinder of the fuel injection valve and the press-fitting load [N] required for press-fitting.

[0022] Figure 7 is used with Figure 7 B's existing throttle orifice components are compared to illustrate Figure 7 A through Figure 1 An explanatory diagram of the effect of preventing orifice strain achieved by the orifice component.

[0023] Figure 8 It is a cross-sectional view showing an orifice member of a fuel injection valve according to a second embodiment of the present invention.

[0024] Fig. 9 It is a cross-sectional view showing an orifice member of a fuel injection valve according to a third embodiment of the present invention.

[0025] Fig.10 It is a cross-sectional view showing an orifice member of a fuel injection valve according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described using the drawings. Figure 1 1 shows a throttle hole component of a fuel injection valve according to a first embodiment of the present invention. Figure 1 As shown, the fuel injection valve includes a fuel passage 1 and a throttle hole component 3. The fuel passage 1 is arranged in the housing of the fuel injection valve for introducing the injected fuel; the throttle hole component 3 has a throttle hole 2 and is pressed into the inner wall of the fuel passage 1.

[0027] Specifically, the orifice member 3 is press-fitted into and fixed to the fuel inlet cylindrical portion 5 on the upstream side of the portion of the fuel passage 1 where the fuel filter 4 is provided.

[0028] The throttle hole component 3 includes a cylindrical portion 6, an end wall portion 7, and an annular stress absorbing portion 8. The cylindrical portion 6 is fixed to the inner wall of the fuel passage 1 by the above-mentioned press-fitting; the end wall portion 7 covers one end of the cylindrical portion 6 and is provided with the throttle hole 2; the annular stress absorbing portion 8 is interposed between the one end of the cylindrical portion 6 and the outer periphery of the end wall portion 7 and absorbs the stress generated by the above-mentioned press-fitting. In this embodiment, the one end of the cylindrical portion 6 refers to the end on the downstream side.

[0029] The annular stress absorbing portion 8 is connected to one end of the downstream side of the cylindrical portion 6 and the end wall portion 7 via the bent portion 9. The end wall portion 7 is located on the downstream side of the cylindrical portion 6. The orifice member 3 includes a flange portion 10 extending radially outward from the upstream end of the cylindrical portion 6. The flange portion 10 contacts the end of the fuel inlet cylindrical portion 5.

[0030] Figure 2 It shows the situation of forming the throttle hole component 3. Figure 2 As shown, the orifice member 3 is formed by punching a metal plate as a base material using upper and lower dies 11 and 12 having the shape of the orifice member 3 to provide the orifice 2. For example, a stainless steel plate can be used as the metal plate.

[0031] Figure 3 A to 3C show the situation where the throttle hole component 3 is pressed into the fuel inlet tube 5. First, Figure 3 As shown in A, the orifice member 3 is positioned at the opening of the fuel inlet tube 5 so that the orifice 2 side faces the downstream direction. Figure 3 As shown in FIG. 2B , the orifice member 3 is pressed downstream by the pressing member 13 . At this time, the downstream end of the cylindrical portion 6 receives a radially inner force F from the inner wall of the fuel inlet cylindrical portion 5 , generating stress (strain) S in the cylindrical portion 6 .

[0032] However, the stress (strain) S is absorbed and suppressed by the annular stress absorbing portion 8 and the bent portions 9 on both sides thereof, and is therefore not greatly transmitted to the end wall portion 7. The orifice member 3 is further pressed, as shown in FIG. Figure 3 As shown in C, when the flange portion 10 abuts against the end of the fuel inlet tube portion 5, the press-fitting step is completed, and the installation of the throttle hole component 3 to the fuel inlet tube portion 5 is completed.

[0033] At this time, the stress (strain) S caused by the force F from the inner wall of the fuel inlet tube 5 is also absorbed and suppressed by the annular stress absorbing portion 8 and the curved portions 9 on both sides thereof, and is not likely to be transmitted to the end wall portion 7. Therefore, the throttle hole 2 in the throttle hole component 3 after installation can maintain the designed shape and position as much as possible.

[0034] Figure 4A to 4C show the case where the conventional orifice member 3b without the annular stress absorbing portion 8 is pressed into the fuel inlet tube 5. In this case, Figure 4 As shown in A, the throttle hole component 3b is positioned at the opening of the fuel inlet cylinder 5, as shown in FIG. Figure 4 As shown in FIG. 1B, when the orifice member 3b is pressed in by the pressing member 13, the downstream end of the cylindrical portion 6b is subjected to a radially inner force F from the inner wall of the fuel inlet cylindrical portion 5, generating stress (strain) S in the cylindrical portion 6b. The stress (strain) S is directly transmitted to the end wall portion 7b.

[0035] And, if Figure 4 As shown in FIG. 3 , even at the moment when the press-fitting step is completed, the stress (strain) S caused by the force F from the inner wall of the fuel inlet tube 5 is not absorbed but transmitted to the end wall 7b. Therefore, the throttle hole 2 in the throttle hole component 3b after installation is completed. Figure 3 Compared with the orifice 2 in this embodiment, the shape and position of C are changed.

[0036] Figure 5 It is the measured result showing the relationship between the interference [μm] when the throttle hole component 3 is pressed into the fuel inlet cylinder 5 and the deformation amount (diameter change [μm]) of the throttle hole 2. The result is represented by the graph curve A in the figure. According to the result, within the assumed range W of the interference amount during mass production, the diameter change of the throttle hole 2 is approximately 7 [μm] or less.

[0037] On the other hand, in the conventional orifice member 3b (see Figure 4 In the case of (A to 4C), as shown by point B in the figure, the diameter change of the orifice 2 when the interference is 60 [μm] within the assumed range W is 30 [μm], which is much larger than the diameter change of the present embodiment.

[0038] Figure 6 The measured results show the relationship between the interference [μm] and the press-fit load [N] required for press-fitting when the orifice member 3 is press-fitted into the fuel inlet tube 5. The results are shown in the graph curve C. In view of the equipment requirements, the press-fit load is targeted to be 1000 [N] or less.

[0039] like Figure 6 As shown in the curve C in FIG. 1 , it can be seen that within the assumed range W of the interference during mass production, the press-fit load is generally below 400 [N], which is sufficiently lower than the target press-fit load of 1000 [N].

[0040] On the other hand, in the conventional orifice member 3b (see Figure 4In the case of A to 4C), as shown by point D in the figure, the press-in load when the interference is 60 [μm] within the assumed range W is about 750 [N], which is smaller than the target press-in load of 1000 [N], but much larger than the press-in load of the present embodiment.

[0041] As described above, according to the present embodiment, the cylindrical portion 6 of the throttle hole component 3 pressed into the inner wall of the fuel passage 1 absorbs the strain caused by the stress received from the inner wall during the pressing by the annular stress absorbing portion 8, thereby suppressing the strain from being transmitted to the throttle hole 2. Therefore, the throttle hole 2 can maintain the designed size as much as possible, thereby providing a fuel injection valve that suppresses the deviation of the fuel injection performance.

[0042] In addition, the annular stress absorbing portion 8 is connected to one end of the cylindrical portion 6 and the end wall portion 7 via the bent portion 9, respectively. Therefore, the bent portion 9 can be used to control the stress during press-in to be transferred from the cylindrical portion 6 to the annular stress absorbing portion 8 and then to the end wall portion 7, thereby suppressing the stress concentration at the two end edges of the annular stress absorbing portion 8.

[0043] Therefore, according to the throttle hole component 3 of this embodiment, Figure 7 As shown in A, Figure 7 Compared with the conventional orifice component 3b shown in FIG. 1B which is not provided with the annular stress absorbing portion 8, the force F applied to the cylindrical portion 6 during press-in is combined with the stress absorption effect of the annular stress absorbing portion 8 through the curved portion 9, which can more effectively avoid the stress (strain) S generated in the end wall portion 7, and can prevent the orifice 2 from being strained as much as possible. In addition, the pressing force required for press-in can also be reduced.

[0044] In addition, the throttle hole component 3 has a flange portion 10 extending radially outward from the upstream end of the cylindrical portion 6. Therefore, when the throttle hole component 3 is pressed into the fuel passage 1, the posture of the throttle hole component 3 can be easily confirmed by making the flange portion 10 contact with the opening portion of the fuel passage 1.

[0045] Figure 8 The orifice component of the fuel injection valve according to the second embodiment of the present invention is shown. The orifice component 3c corresponds to Figure 1 The throttle hole component 3 is a component obtained by removing the flange portion 10. The other structures of the throttle hole component 3c are the same as those of Figure 1 The throttle hole component 3 is the same and has the same effect.

[0046] Fig. 9 The throttle hole component of the fuel injection valve according to the third embodiment of the present invention is shown. In the throttle hole component 3d, the annular stress absorbing portion 8d has a truncated cone shape whose diameter decreases toward the upstream side. In addition, the diameter of the end wall portion 7d is Figure 1The diameter of the end wall portion 7 of the throttle hole component 3 is about half.

[0047] Therefore, the cylindrical portion 6d is larger than Figure 1 The cylindrical portion 6 of the orifice member 3 is longer. The bending angle of the bent portion 9d between the cylindrical portion 6d and the annular stress absorbing portion 8d is about 45°. The bending angle of the bent portion 9d between the annular stress absorbing portion 8c and the end wall portion 7d is about 135°.

[0048] When the orifice component 3d is used, the force F applied to the cylindrical portion 6 when the orifice component 3d is pressed into the fuel inlet cylinder portion 5 can be more effectively suppressed by combining the stress absorption effect of the curved portion 9d and the annular stress absorbing portion 8d, thereby more effectively suppressing the stress (deformation) S generated in the end wall portion 7d and preventing the orifice 2 from deforming as much as possible. Figure 1 The situation of the throttle hole component 3 is the same and has the same effect.

[0049] Regarding the analytical prediction value of the deformation amount of the diameter of the orifice 2 caused by press-fitting, for example, if Figure 1 In the case of the orifice component 3, it is 0.008 [mm], and in the case of the orifice component 3d, it is about 0.01 [mm]. In addition, regarding the analytical prediction value of the press-in load when the fuel inlet cylinder 5 is pressed, if the Figure 1 In the case of the orifice component 3, it is 419.1 [N], and in the case of the orifice 2 using the orifice component 3d, it is about 707.3 [N].

[0050] Fig.10 The throttle hole component 3e of the fuel injection valve according to the fourth embodiment of the present invention is shown. In the throttle hole component 3e, the annular stress absorbing portion 8e, the bent portions 9e on both sides thereof, and the end wall portion 7e are located on the upstream side of the cylindrical portion 6e. In addition, a tapered guide portion 14 whose diameter decreases toward the downstream side is formed at the lower end of the cylindrical portion 6e to form a guide when the throttle hole component 3e is pressed into the fuel inlet cylindrical portion 5.

[0051] That is, in addition to the guide portion 14, the orifice member 3e has Figure 8 The upstream and downstream sides of the throttle hole component 3c are reversed. In addition to not having the effect of the flange portion 10, the throttle hole component 3e also has other functions similar to Figure 1 The same effect is achieved as in the case of the throttle hole component 3.

[0052] Regarding the analytical prediction value of the deformation amount of the diameter of the orifice 2 caused by press-fitting, for example, if Figure 1In the case of the orifice component 3, it is 0.008 [mm], and in the case of the orifice component 3e, it is about 0.017 [mm]. In addition, regarding the analytical prediction value of the press-in load when the fuel inlet cylinder 5 is pressed, if the Figure 1 In the case of the orifice component 3, it is 419.1 [N], and in the case of the orifice component 3e, it is about 547.4 [N].

[0053] Although the embodiments of the present invention have been described above, the present invention is not limited thereto. For example, the bent portions on both sides of the annular stress absorbing portion may not be provided.

[0054] Explanation of symbols

[0055] 1…fuel passage; 2…throttle hole; 3, 3b, 3c, 3d, 3e…throttle hole component; 4…fuel filter; 5…fuel inlet cylinder; 6, 6b, 6c, 6d, 6e…cylindrical portion; 7, 7b, 7c, 7d, 7e…end wall portion; 8, 8c, 8d, 8e…annular stress absorbing portion; 9, 9c, 9d, 9e…bent portion; 10…flange portion; 11…mold; 12…mold; 13…pressing component; 14…guide portion; A…chart curve; B…point; C…chart curve; D…point; F…force; S…stress (strain); W…assumed range of interference.

Claims

1. A fuel injection valve comprising a fuel passage and a throttle member, wherein the fuel passage is for introducing injection fuel, and the throttle member has a throttle hole and is pressed into the inner wall of the fuel passage, The fuel injection valve is characterized in that The throttle hole component comprises: a cylindrical portion, which is fixed to the inner wall by the press-fitting; an end wall portion, which covers one end of the cylindrical portion and is provided with the throttle hole; and an annular stress absorbing portion, which is located between the one end of the cylindrical portion and the outer periphery of the end wall portion and absorbs the stress caused by the press-fitting.

2. The fuel injection valve according to claim 1, characterized in that: The annular stress absorbing portion is connected to the one end of the cylindrical portion and the end wall portion via a bent portion, respectively.

3. The fuel injection valve according to claim 1, characterized in that: The end wall portion is located on the downstream side of the cylindrical portion, and the orifice member includes a flange portion extending radially outward from an upstream end portion of the cylindrical portion.

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