JPH05248583A - Connection structure of branch pipe in manifold for high pressure fuel - Google Patents

Abstract

PURPOSE:To surely connect a main pipe to a branch pipe by externally fitting a joint metal piece a circumferential wall part of the main pipe, engaging a pushingly pressing head part of the branch pipe with the pressure receiving seat of a through hole in the circumferential wall part of the main pipe, and then screwing a nut built in the branch pipe into the screw hole of the joint metal piece. CONSTITUTION:A plurality of drilled through holes 3 which communicate with an inner flow passage 2 are provided in a circumferential wall part of a main pipe 1 where high pressure fuel flows in the longitudinal direction. The respective branch pipes are continuously provided in the respective through holes 3. In this case, the inner circumference of the tips of the respective through holes 3 are formed on the pressure receiving seat 3' opening outward. A separate joint metal piece 4 is externally fitted to the outer circumferential wall part of the main pipe 1 side so as to surround the pressure receiving seat 3'. In addition, a pushingly pressing head part 6 formed in the connection end part of the branch pipe 5 is engaged with the pressure receiving seat 3'. In this condition, the branch pipe 5 is connected to the main pipe 1 by screwing the nut 7 built in the branch pipe 5 side into the screw hole of the joint metal piece 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a diesel internal combustion engine for various vehicles and the like, and a high pressure fuel manifold disposed near the engine as a fuel supply path to the engine, particularly 1000 kg.
The present invention relates to an improvement in the connection structure of branch branch pipes in an ultrahigh pressure fuel manifold of f / cm ² or more.

[0002]

2. Description of the Related Art In recent years, as a connection structure of this kind, for example, as shown in FIG. 3, a plurality of internal flow passages are provided in the circumferential wall of a main pipe (11) through which a high pressure fuel flows, along the lengthwise direction thereof. Road (1
In the present condition in which the branch branch pipe (14) is inserted into each of the through-holes (13) connected to 2) and brazed or welded (W) to each other so as to be connected to each other and subjected to the practical test. there were.

[0003]

However, in such a connection structure, due to the mutual fitting state requiring connection strength and uncertain welding, etc., when the engine mechanism is improved, it is difficult to use. Leakage due to brittleness of the brazed part or welded (W) part and branch branch pipe due to repeated supply of ultra-high flow pressure exceeding 1000 kgf / cm ² and vibration from the engine
There was a tendency to have problems such as withdrawal of (14).

In order to solve the above-mentioned problems extremely effectively, the present invention surrounds the pressure-receiving seat surface portion of the through hole by a separate fitting and externally fits it to the main pipe side, and a branch branch is provided in the through hole portion. By connecting the pressing head of the connecting end on the pipe side by abutting and screwing and tightening with a nut, it is possible to connect easily without requiring welding at the connecting part with the branch branch pipe. It is an object of the present invention to propose a connection structure that can sufficiently cope with the above-mentioned ultra-high flow pressure even under a vibrating state, and at the same time there is no fear of leakage at the connection portion and disconnection of the branch branch pipe. It is what

[0005]

SUMMARY OF THE INVENTION According to the present invention, a branch pipe is provided in a peripheral wall portion of a main pipe through which high-pressure fuel flows and a plurality of through holes connected to internal flow passages provided along the length direction of the main pipe. In the connection structure formed by continuously connecting the through holes, the inner circumference of the tip of each of the through holes is formed as a pressure receiving seat surface that opens outward, and the pressure receiving seat surface portion is further surrounded by an outer peripheral wall portion on the main pipe side from a separate body. Of the fitting metal fitting, which is fitted to the pressure receiving seat surface portion with the pressing head formed at the connecting end portion of the branch branch pipe in abutting engagement with the pressure receiving seat surface portion, The gist of the present invention is a connecting structure of a branch branch pipe in a high-pressure fuel manifold that is connected by being screwed into a screw hole. Further, the joint fitting is a short circular ring body or a square ring body. The pressure receiving seat surface is provided in a conical shape or an arc shape. Conical comprising a pressing head from truncated, or is to constitute in an arc shape.

[0006]

Since the present invention is constructed in this manner, the pressing head of the branch pipe is abutted and engaged with the pressure receiving seat surface portion by the fitting fitting fitted on the peripheral wall portion of the main pipe and screwed by the nut. Will be tightened and connected.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a side view showing a connecting structure of branch and branch pipes in a high-pressure fuel manifold of the present invention, and FIG. 2 is a part of FIG. It is a longitudinal sectional view by notch, (1) outer diameter is about 20 mm, wall thickness 6 mm
It is a main pipe made of a thick metal tube with a relatively small diameter, and a plurality of inner ends of the tip are opened outward in a conical or arcuate shape along the lengthwise direction on the peripheral wall portion thereof. Pressure bearing surface
As (3 '), a through hole (3) connected to the internal flow passage (2) is provided. (4) is a short circular ring body or a square ring body that surrounds each pressure receiving seat surface (3 ') part and is externally fitted to the outer peripheral wall part on the main pipe (1) side. The pressure receiving seat surface is a fitting metal fitting that is a conical or arcuate pressing head (6) formed by a truncated head formed at the connection end of the branch pipe (5).
Tighten by screwing the nut (7) assembled on the side of the branch pipe into the screw hole formed on the inner peripheral surface of the fitting (4) in the state of abutting engagement with (3 '). Then, they are connected and configured.

A sealing material such as a copper packing material may be interposed between the pressing head portion (6) and the pressure receiving surface (3 ').

[0009]

As described above, the connection structure according to the present invention is based on the connection structure of the branch branch pipe (5) by the nut (7) at the fitting metal fitting (4) fitted on the main pipe (1). Therefore, no brazing or fine welding work is required at the connection with the branch branch pipe (5) at the time of connection, and the nut (7) can be easily connected by screwing and tightening, and the fitting (4 ), It is possible to sufficiently cope with ultra-high flow pressure even under the vibrating state by the engaging structure over the entire circumference of the main wall (1) to the outer peripheral wall of the main pipe (1). This is a very useful connection structure in which there is no fear of leakage of the pipe and separation of the branch branch pipe (5).

[Brief description of drawings]

FIG. 1 is a side view of a connection structure of a branch pipe in a high pressure fuel manifold showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view taken along the partially cutaway view of FIG.

FIG. 3 is a partially cutaway vertical sectional view showing a conventional example.

[Explanation of symbols]

 1 main pipe 3 through hole 3'pressure receiving surface 4 joint fitting 5 branching branch pipe 6 pressing head 7 nut

Claims (3)

[Claims] 1. A connection in which a branched branch pipe is continuously provided in a peripheral wall portion of a main pipe through which high-pressure fuel flows, along a lengthwise direction thereof, and in a plurality of through-hole portions connected to internal flow passages. In the structure, the inner circumference of the tip of each of the through holes (3) is made a pressure receiving seat surface (3 ') that opens outward, and the pressure receiving seat surface portion is further surrounded by the outer peripheral wall portion on the main pipe (1) side. A state in which a separate fitting (4) is fitted onto the pressure receiving surface (3 ') and the pressing head (6) formed at the connecting end of the branch branch pipe (5) is abutted and engaged. Then, the fitting (4) by the nut (7) incorporated on the side of the branch pipe
A connection structure for branching branch pipes in a high-pressure fuel manifold, characterized in that they are connected to each other by being screwed into the screw holes of the. 2. The fitting according to claim 1, wherein
(4) A connecting structure of branch and branch pipes in a high-pressure fuel manifold, characterized in that (4) is provided in a short-sized annular ring body or a square ring body. 3. The pressure-receiving seat surface (3) according to claim 1,
') Is provided in a conical or arcuate shape, and the pressing head (6) is formed in a conical or arcuate shape consisting of a frusto-conical shape. Connection structure.