JPH04314960A - Gasket for fuel injection nozzle - Google Patents

Abstract

PURPOSE:To correctly position a gasket between the opposed bottom surfaces of a nozzle and an installation hole by the linear contact of the upper and lower surfaces of the gasket. CONSTITUTION:A gasket 30 has the annular supporting parts 36 and 38 which are formed by bending the section to each mountain shape, on one-side surface and has an annular supporting part 40 which is formed by bending the section to a mountain shape, on the other surface. Further, the gasket 30 has a supporting part 42 having the section projecting in the radial direction in a mountain shape on the peripheral edge part. The gasket 30 linear-contacts the opposed wall surfaces 22-1 and 24-1 of a nozzle 22 and a nozzle hole 24, in annular form at the top edges of the annular supporting parts 36, 38, and 40. Accordingly, when the nozzle 22 is tightened on an installation hole 24, the gasket 30 slides in the lateral direction, and eccentricity is corrected, and correct positioning can be achieved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a gasket for a fuel injection nozzle used in the attachment of the fuel injection nozzle to a cylinder head in an internal combustion engine, such as a diesel engine.

0002

2. Description of the Related Art In a diesel engine, when a fuel injection nozzle is attached to a fuel injection nozzle attachment hole formed in a cylinder head, a sealing gasket is interposed between the opposing bottom surfaces of the attachment hole and the fuel injection nozzle. Utility Model Application Publication No. 58-45951 as the structure of the conventional gasket
In this issue, an annular support part is formed on the surface facing the bottom of the mounting hole that is bent into a chevron-shaped cross section so as to protrude toward the opposite surface, and an annular support section is formed on the gasket surface facing the bottom surface of the fuel injection nozzle on the opposite surface. The structure has surface contact at the center.

0003

[Problems to be Solved by the Invention] When installing a fuel injection nozzle, the gasket is first inserted into the fuel injection nozzle hole, and then the fuel injection nozzle is inserted, and the fuel injection nozzle is screwed into the mounting hole. Since the fuel injection nozzle hole is inclined with respect to the vertical plane, the gasket is positioned downwardly with respect to the hole due to its weight before being fastened. Such eccentricity is normally absorbed by some lateral movement of the gasket during tightening. However, in the prior art, one surface of the gasket is in line contact with the opposing bottom surfaces of the mounting hole and the bottom surface of the fuel injection nozzle, but the other surface is in surface contact. Therefore, the friction with the gasket at the area of surface contact is large, making it difficult to move in the lateral direction smoothly, and it tends to be difficult to correct eccentricity during tightening. As a result, in the conventional technology, when tightening, the peripheral edge of the gasket gets wedged like a wedge in the gap between the opposing peripheral surfaces of the fuel injection nozzle and the mounting hole, and a force pushing the nozzle in the lateral direction is applied, resulting in so-called nozzle stick. may occur. The purpose of this invention is to prevent nozzle sticking and to ensure that the gasket is always properly positioned between the nozzle mounting hole and the opposing bottom surface of the fuel injection nozzle.

0004

[Means for Solving the Problems] According to the present invention, in a structure in which a fuel injection nozzle is attached to a nozzle attachment hole formed in a cylinder head via a gasket, the gasket is connected to a surface facing the bottom surface of the nozzle attachment hole. There is provided a gasket for a fuel injection nozzle, characterized in that an annular support portion is formed on each of the surfaces opposite to the bottom surface of the fuel injection nozzle, the annular support portion being bent to have a chevron-shaped cross section so as to protrude toward the opposing surface. Ru.

[0005]

[Operation] When the fuel injection nozzle is attached to the nozzle mounting hole, the gasket located between the opposing surfaces of the nozzle and the mounting hole is in line contact with both opposing surfaces,
Perform the gasket's lateral movement so that the gasket is properly centered and positioned.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, which is a sectional view of the vicinity of a combustion chamber of a diesel engine, 10 is a cylinder head, 12 is a cylinder block, and 14 is a piston. A sub-chamber element 16 is fitted from the bottom of the cylinder head 10 to form a combustion chamber 18. 20 is a glow plug, and 22 is a fuel injection nozzle, which are provided so as to face the combustion chamber 18. To explain the mounting structure of the fuel injection nozzle 22 in more detail, the cylinder head 10 forms a fuel injection nozzle mounting hole 24 whose axis is inclined with respect to a vertical plane. This hole 24 communicates with the combustion chamber 18 via a connecting hole 26 . Opposing bottom surface 24- between the hole 26 and the fuel injection nozzle 22
1 and 22-1, a gasket 30 made of a heat-resistant metal thin plate is arranged.

FIG. 2 shows a perspective view of a single gasket 30, and for ease of understanding, the gasket 30 is shown divided in half along the diameter line. The gasket 30 is the fuel injection nozzle 22
It has an annular shape with a hole 34 in the center that allows passage of fuel injected from the hole. The gasket 30 has an annular first support portion 36 and an outer annular second support portion 38.
and a third annular support part 40 between the first support part 36 and the second support part 38, and the cross-sectional shape of the first and second support parts 36, 38 is chevron-shaped. It is bent, and its chevron-shaped tip projects upward. A third annular support portion 40 is provided between the first support portion 36 and the second support portion 38 and is bent into a chevron-shaped cross section, with the tip of the chevron protruding downward. Further, a fourth annular support portion 42 is provided along the outer periphery of the gasket 30, and this fourth
The supporting portion 42 has a chevron-shaped tip protruding outward in the radial direction. This fourth portion 42 includes an upper side 42-1 and a lower side 42-1.
-2.

FIG. 3 shows the fuel injection nozzle 22 installed in the mounting hole 24 via the gasket 30 of the present invention. In the gasket 30, a first support part 36 and an annular second support part 38 on the outside thereof are in annular line contact with the bottom surface 22-1 of the fuel injection nozzle 22, and the bottom surface 22-1 of the mounting hole 24
4-1, the third annular support portion 40 is in annular line contact with the support portions 36, 38, and 40. In this attached state, the angular shapes of the support portions 36, 38, and 40 are flattened, and the diameters are slightly larger, but the attachment holes are Although the fourth support portion 42 is in contact with the inner circumferential surface of 24, some clearance δ remains at the upper portion.

FIG. 4 shows the state in which the gasket 30 is initially installed in the mounting hole for mounting the fuel injection nozzle. Since the center line of the mounting hole 24 is inclined with respect to the vertical plane, the supporting portion 42 of the gasket 30 contacts the lower inner circumferential surface of the mounting hole 24 . That is, the gasket 30
is mounted eccentrically downward with respect to the mounting hole 24, leaving a large clearance Δ on the upper side. At this time, each of the supporting portions 36, 38, 40, and 42 of the gasket 30 assumes the original chevron-shaped angle.

When inserting and fastening the fuel injection nozzle 22 into the mounting hole 24, the gasket 30 is attached to the fuel injection nozzle 2.
The first support portion 36 and the annular second support portion 38 outside the first support portion 36 are in annular line contact with the bottom surface 22-1 of the second
The fourth support portion 40 contacts the bottom surface 24 - 1 of the attachment hole 24 , and the fourth support portion 42 contacts the lower inner circumferential surface of the attachment hole 24 . By tightening these support parts 36, 38,
40,42 are crushed. During this crushing process, the gasket 30 is gradually flattened, and the support portion 42 is attached to the mounting hole 2.
Coupled with the fact that the upper and lower support parts 36, 38, 40 are in contact with the lower inner peripheral surface of 4, the upper and lower support parts 36, 38, 40 are
The eccentricity is alleviated and the clearance Δ gradually decreases, eventually reaching the state shown in Figure 3 (
Clearance = δ).

In the present invention, the fourth support portion 42 protruding in the radial direction on the outer periphery has the upper and lower chevron-shaped surfaces 42-1 and 42-1.
-2. Surface 42- opposite to surface 22-1
1 is inclined downward, so there is no risk of it getting caught in the annular gap between the opposing circumferential surfaces of the fuel injection nozzle 22 and the mounting hole 24. Therefore, the line contact between the upper and lower support parts 36, 38, 40 and the opposing surfaces 22-1, 24-1 makes it easy to slide, and "alignment" by sliding during tightening can be easily performed. be exposed. When the gasket 30 is inserted vertically opposite to the orientation shown in FIGS. 3 and 4, the first support portion 36 and the second support portion 38 contact the bottom surface 24-1 of the nozzle hole 24. , the third support part 40 on the opposite side contacts the bottom surface 22-1 of the nozzle 22, but since it is only a line contact, the function of eliminating eccentricity by sliding can be obtained in the same manner as in FIGS. 3 and 4. Further, the fourth support portion 42 has upper and lower sides 42-1 and 42-2 forming a chevron-shaped cross section.
Even if the gasket is installed upside down, the same anti-entanglement function can be obtained.

FIG. 5 shows the case of an annular gasket 130 having a circular cross section, which is the most usual structure, but when assembled, the gasket 130 is positioned offset so as to butt against the lower peripheral surface of the mounting hole 124 (with a gap Δ remains on the top)
Since this is unavoidable, when the fuel injection nozzle 122 is fastened, the gasket 130 is inserted into the annular gap between the opposing circumferential surfaces of the fuel injection nozzle 122 and the mounting hole 124 with the arrow a.
It is easy to get caught in the nozzle 12 due to its wedge action.
2 is pressed in the lateral direction as shown by arrow b, which may cause nozzle stick.

FIG. 6 shows the case of Utility Model Application No. 58-45951. The gasket 230 has an annular support portion 230-1 having a chevron-shaped cross section on its lower surface, but its upper surface 230-2 is flat. In this case, since the contact area on the upper surface 230-2 is large, the gasket 230-2 is tightened due to friction.
Sliding is difficult to occur. Second, since the peripheral portion 230-3 faces upward, there is a drawback that the peripheral portion 230-3 is likely to be caught in the gap between the opposing circumferential surfaces of the fuel injection nozzle 222 and the attachment hole 224. (a) shows the state before tightening, and (b) shows the tightening process. (b), the peripheral part 230-3 of the gasket 230 is the nozzle body 2.
22 and the nozzle hole 234 are shown in a state where they are caught in an annular gap between the opposing peripheral surfaces.

[0014]

[Effects of the Invention] In this invention, the annular support portions on the upper and lower surfaces of the gasket are supported by support portions with a chevron-shaped cross section, and since both surfaces are in line contact with the opposing surface, the eccentricity correcting action due to sliding during tightening is effective. Biting can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the vicinity of a combustion chamber of a diesel engine.

FIG. 2 is a perspective view showing the gasket of the present invention cut in half.

FIG. 3 is a sectional view showing the gasket of the present invention in a fully assembled state.

FIG. 4 is a sectional view showing the gasket of the present invention in a state before assembly.

FIG. 5 is a sectional view showing a conventional gasket in a state of being assembled.

FIG. 6 is a cross-sectional view showing another conventional gasket in a state before assembly (a) and in a state after assembly (b).

[Explanation of symbols]

10...Cylinder head 12...Cylinder block 14...Piston 22...Fuel injection nozzle 24...Nozzle mounting hole 30...Gasket 36...First support part 38...Second support part 40...Third support part 42...Fourth support part

Claims (1)

[Claims] Claim 1: In a structure in which a fuel injection nozzle is attached to a nozzle mounting hole formed in a cylinder head via a gasket, the gasket has a surface facing the bottom of the nozzle mounting hole and a surface facing the bottom of the fuel injection nozzle. 1. A gasket for a fuel injection nozzle, characterized in that an annular support portion is formed on each of the surfaces thereof, the annular support portion being bent into a chevron-shaped cross section so as to protrude toward the opposing surface.