GASOLINE DIRECT-INJECTION RAIL

Abstract

To make it possible to prevent damage to a brazed part without increasing the thickness of a rail body even when the rail body and an end cap are fixed to each other by brazing, in view of high-pressure gasoline direct injection systems of the future. A gasoline direct injection rail comprising end caps 2 disposed inside respective ends of a rail body 1, with an outer circumference 3 of each end cap 2 and an inner circumference 4 of the rail body 1 being fixed to each other by brazing, wherein a reinforcing ring 6 having an axial length L of L5 mm is provided on the outer circumference 3 of the rail body 1; a first end 10 on an end cap 2 side of the reinforcing ring 6 is positioned so as not to overlap a brazed part 12 between the rail body 1 and the end cap 2; a distance X from the first end 10 of the reinforcing ring 6 to a distal end 13 of the brazed part 12 is 0 mmX15 mm; and a thickness of the reinforcing ring 6 is 40% or more of a thickness of the rail body 1.

Claims

1. A gasoline direct injection rail comprising end caps disposed inside respective ends of a rail body, with an outer circumference of each end cap and an inner circumference of the rail body being fixed to each other by brazing, wherein a reinforcing ring having an axial length L of L5 mm is provided on an outer circumference of the rail body; a first end on an end cap side of the reinforcing ring is positioned so as not to overlap a brazed part between the rail body and the end cap; a distance X from the first end of the reinforcing ring to a distal end of the brazed part is 0 mmX15 mm; and a thickness of the reinforcing ring is 40% or more of a thickness of the rail body.

2. A gasoline direct injection rail comprising end caps disposed inside respective ends of a rail body, with an outer circumference of each end cap and an inner circumference of the rail body being fixed to each other by brazing, wherein a reinforcing ring is provided on an outer circumference of the rail body; a first end on an end cap side of the reinforcing ring is positioned so as to overlap a brazed part between the rail body and the end cap; a distance Y from a distal end of the brazed part to a second end of the reinforcing ring is Y5 mm; and a thickness of the reinforcing ring is 40% or more of a thickness of the rail body.

3. The gasoline direct injection rail according to claim 1, wherein the axial length L of the reinforcing ring is L30 mm.

4. The gasoline direct injection rail according to claim 2, wherein the distance Y from the distal end of the brazed part to the second end of the reinforcing ring is Y30 mm.

5. The gasoline direct injection rail according to claim 1, wherein the reinforcing ring is fixed to the rail body by way of brazing, shrink fitting, or welding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a cross-sectional view showing the first embodiment of the present invention.

[0027] FIG. 2A and FIG. 2B depict graphs showing the relationship between the stress ratio and the distance X from the first end of the reinforcing ring to the distal end of the brazed part.

[0028] FIG. 3 is a perspective view showing the first embodiment.

[0029] FIG. 4 is a cross-sectional view showing the second embodiment.

[0030] FIG. 5 is a cross-sectional view showing the third embodiment.

[0031] FIG. 6 is a perspective view showing the third embodiment.

[0032] FIG. 7 is a cross-sectional view showing a conventional example.

[0033] FIG. 8 is a cross-sectional view showing a conventional example when an internal pressure is exerted.

MODES FOR CARRYING OUT THE INVENTION

First Embodiment

[0034] The first embodiment of the first invention of the present application will now be described below with reference to FIGS. 1 to 3. First, (1) indicates a rail body, and the rail body (1) has an outer diameter of 22 mm and an inner diameter of 17 mm. The ratio of a thickness t to an outer diameter D of the rail body (1) is 0.1. The rail body (1) is made of stainless steel. In this embodiment, the rail body (1) is made of stainless steel as described above, whereas the rail body (1) can also be made of steel in other embodiments. Cylindrical end caps (2), each having an outer diameter corresponding to the inner diameter of the rail body (1), are disposed inside the respective ends of the rail body (1).

[0035] A brazing filler metal (5) is disposed between an outer circumference (3) of each end cap (2) and an inner circumference (4) of the rail body (1) to fix the end cap (2) and the rail body (1) to each other by brazing. A reinforcing ring (6) is attached to an outer circumference (7) of the rail body (1). The reinforcing ring (6) is in a cylindrical shape and has an axial length L=20 mm, and the inner circumference thereof is fixed to the outer circumference (7) of the rail body (1) by way of brazing. In this embodiment as well as the second and third embodiments below, the reinforcing ring (6) is fixed to the rail body (1) by brazing as described above, but it is also possible in other embodiments that the reinforcing ring (6) is securely disposed on the rail body (1) by way of shrink fitting or welding.

[0036] The reinforcing ring (6) has a thickness that is 120% of the thickness t of the rail body (1). The reinforcing ring (6) and the end cap (2) are made of stainless steel or steel. The rail body (1) used in the gasoline direct injection rail of the present invention preferably have dimensions such that the outer diameter D is 10 mm to 25 mm, the inner diameter is 7 mm or more, and the ratio of the thickness t to the outer diameter D is t/D=0.1 to 0.25.

[0037] In this embodiment, as shown in FIG. 1, the reinforcing ring (6) is attached to the rail body (1) such that the first end on the end cap (2) side of the reinforcing ring (6) is positioned so as not to overlap a brazed part (12) between the rail body (1) and the end cap (2), and a distance X from a first end (10) of the reinforcing ring (6) to a distal end (13) of the brazed part (12) is X=5 mm.

[0038] As described above, the length L of the reinforcing ring (6) is L5 mm, the distance X from the first end (10) of the reinforcing ring (6) to the distal end (13) of the brazed part (12) is 0 mmX15 mm, and the thickness of the reinforcing ring (6) is 40% or more of the thickness of the rail body (1), and thereby the reinforcing ring (6) is provided on a part of the outer circumference (7) of the rail body (1) where the stress or the displacement generated due to an internal pressure is large. Accordingly, deformation of the rail body (1) in the diameter increasing direction can be suppressed, and it is thus possible to prevent damage to the brazed part (12).

Second Embodiment

[0039] While the distance X from the first end (10) of the reinforcing ring (6) to the distal end (13) of the brazed part (12) is X=5 mm in the first embodiment, X is 0 mm in the second embodiment of the first invention of the present application as shown in FIG. 4. As for the other dimensions, the reinforcing ring (6) has an axial length L=20 mm, and the thickness thereof is 120% of the thickness of the rail body (1), as in the first embodiment. Thus, in the second embodiment as well, X is within a range of 0 mmX15 mm, moreover the length L of the reinforcing ring (6) is L5 mm, and the thickness of the reinforcing ring (6) is 40% or more of the thickness of the rail body (1), and thereby, in the second embodiment as well, the reinforcing ring (6) is provided on a part of the outer circumference (7) of the rail body (1) where the stress or the displacement is large. Accordingly, deformation of the rail body (1) in the diameter increasing direction is suppressed, thus making it possible to prevent damage to the brazed part (12).

Third Embodiment

[0040] While the reinforcing ring (6) is securely disposed on the rail body (1) such that the first end (10) on the end cap (2) side of the reinforcing ring (6) is positioned so as not to overlap the brazed part (12) between the rail body (1) and the end cap (2) in the first and second embodiments above, the reinforcing ring (6) is securely disposed such that the first end (10) on the end cap (2) side of the reinforcing ring (6) is positioned so as to overlap the brazed part (12) between the rail body (1) and the end cap (2) in the third embodiment in the second invention of the present application.

[0041] When the third embodiment is explained in reference to FIGS. 5 and 6, the outer diameter and the inner diameter of the rail body (1), the ratio between the outer diameter D and the thickness t of the rail body (1), and the material of the rail body (1) in this embodiment are the same as those in the first embodiment. The cylindrical end caps (2), each having an outer diameter corresponding to the inner diameter of the rail body (1), are disposed inside the respective ends of the rail body (1), and the outer circumference (3) of each end cap (2) and the inner circumference (4) of the rail body (1) are brazed to each other with the brazing filler metal (5). The reinforcing ring (6) is attached to the outer circumference (7) of the rail body (1). The reinforcing ring (6) is in a cylindrical shape and has an axial length L=30 mm, and the inner circumference thereof is fixed to the outer circumference (7) of the rail body (1) by way of brazing. The thickness of the reinforcing ring (6) is 120% of the thickness of the rail body (1).

[0042] As shown in FIGS. 5 and 6, the reinforcing ring (6) is attached to the rail body (1) such that the first end (10) on the end cap (2) side of the reinforcing ring (6) is positioned so as to overlap the brazed part (12) between the rail body (1) and the end cap (2), and the end face on the first end side of the rail body (1) is flush with the end face on the first end (10) side of the reinforcing ring (6). Moreover, the distance Y shown in FIG. 5 from the distal end (13) of the brazed part (12) between the rail body (1) and the end cap (2) to the second end (11) of the reinforcing ring (6) is Y=20 mm.

[0043] As described above, the reinforcing ring (6) is securely disposed on the rail body (1) such that the first end (10) on the end cap (2) side of the reinforcing ring (6) is positioned so as to overlap the brazed part (12) between the rail body (1) and the end cap (2), the distance Y from the distal end (13) of the brazed part (12) to the second end (11) of the reinforcing ring (6) is Y5 mm, and the thickness of the reinforcing ring (6) is 40% or more of the thickness of the rail body (1), and thereby the reinforcing ring (6) is provided on a part of the outer circumference (7) of the rail body (1) where the stress or the displacement generated in the rail due to an internal pressure is large. Accordingly, deformation of the rail body (1) in the diameter increasing direction can be suppressed, and it is thus possible to prevent damage to the brazed part (12).

DESCRIPTION OF THE REFERENCE NUMERALS

[0044] 1 Rail body [0045] 2 End cap [0046] 3 Outer circumference (End cap) [0047] 4 Inner circumference [0048] 6 Reinforcing ring [0049] 7 Outer circumference (Rail body) [0050] 10 First end [0051] 11 Second end [0052] 12 Brazed part [0053] 13 Distal end