JP2599652B2 - Connection structure of branch pipe in high pressure fuel manifold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a high-pressure fuel manifold, especially a high-pressure fuel manifold, which is disposed in the vicinity of a diesel internal combustion engine such as various axles as a fuel supply path to the engine.
The present invention relates to an improvement in a connection structure of a branch pipe in an ultrahigh-pressure fuel manifold of 0 kgf / cm ² or more.

[0002] In recent years, the pressure of supplied fuel has been increased to reduce particulates and NOx in diesel internal combustion engines. However, the higher the pressure of the fuel, the more difficult it is to control the timing of the fuel injection device with respect to the fuel injection pump, particularly at the beginning and end of the injection. Therefore, the fuel is previously pressurized to an ultra-high pressure of 1000 kgf / cm ² or more by a high-pressure pump and stored in the storage chamber, and the injection nozzle is pressurized by providing a mechanically or electrically controlled opening / closing valve. A method of controlling the supply of the ultra-high pressure fuel to the combustion chamber by opening and closing the valve has been devised.

[0003]

2. Description of the Related Art As shown in FIG. 3, for example, as a connection structure used in this type of system, the connection structure extends over the peripheral wall of a main pipe (11) serving as a pressure storage chamber through which high-pressure fuel flows. Through holes (1) connected to internal flow passages (12)
In each of the parts 3), the branch branch pipes (14) to be connected to the high-pressure pump side or the injection nozzle side are fitted and brazed or welded (W) to each other in a state of being inserted, and subjected to a practical test. Was in the current situation.

[0004]

However, in such a connection structure, the above-mentioned state of insertion and unreliable welding, etc., which require connection strength, cause a problem when the engine mechanism is used to improve the engine mechanism. The repetitive supply of an ultra-high flow pressure of 1000 kgf / cm ² or more, and the vibration from the engine often cause leakage and detachment of the branch pipe (14) due to embrittlement of a brazed or welded (W) part. There was a tendency to have problems such as occurrence.

In order to solve the above-mentioned problem extremely effectively, the present invention surrounds the pressure receiving seat surface of the through hole by a separate fitting, and is fitted to the main pipe side. The pressing head of the connection end on the pipe side is abutted and engaged and screwed and fastened with a nut to form a connection, so that welding and the like at the connection with the branch branch pipe are not required and connection can be made easily. It is an object of the present invention to provide a connection structure that can sufficiently cope with the ultra-high flow pressure even under a vibrating state, and at the same time, has no fear of leakage at a connection portion and detachment of a branch branch pipe. It is assumed that.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a through-hole which is continuous with a plurality of internal flow passages provided in a peripheral wall portion of a thick and small-diameter main pipe through which high-pressure fuel flows. In a connection structure in which thick and small-diameter branch branch pipes are respectively connected to the portions, a conical or arc-shaped pressure receiving seat surface that opens outward at the tip end of each through hole, A separate fitting fitting is externally fitted to the outer peripheral wall of the main pipe side surrounding the pressure receiving seat surface, and a truncated conical shape formed at the connection end of the branch pipe on the pressure receiving seat surface, or A branch in a high-pressure fuel manifold connected and fastened by screwing the joint fitting into a threaded hole with a nut incorporated into the branch branch pipe while the pressing head of the arcuate shape is in abutting engagement. It is intended to have a connection structure of a branch pipe, and further, the joint fitting is a short annular body, or And it constitutes provided in the ring body.

[0007]

Since the present invention is constructed as described above, the conical or arc-shaped pressure receiving seat surface is formed by a fitting fitting externally fitted to the peripheral wall of the thick and thin main pipe acting as an accumulating chamber. By contacting and engaging a conical or arc-shaped pressing head consisting of a thick, thin-diameter branch branch pipe with a truncated end, tightening it by screwing with a nut, and connecting it under vibration, Even with this, it is possible to sufficiently cope with an ultra-high flow pressure of 1000 kgf / cm ² or more, and at the same time, to achieve a connection structure free from leakage at the connection portion and detachment of the branch pipe.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a connection structure of a branch pipe in a high-pressure fuel manifold of the present invention, and FIG. 2 is a part of FIG. It is a longitudinal cross-sectional view by notch, (1) is a main pipe made of a relatively thin and thick metal pipe having an outer diameter of about 20 mm and a thickness of about 6 mm, and a peripheral wall portion having a length. A plurality of through-holes (3) are formed as pressure-receiving seat surfaces (3 ') that open outwardly in a conical or arcuate shape at a plurality of inner peripheral ends in a direction. is there. (4) a short annular body or a square annular body which surrounds each of the pressure receiving seat surfaces (3 ') and is externally fitted to the outer peripheral wall on the main pipe (1) side. A pressure fitting head (6) formed of a truncated cone formed at the connection end of a thick and small-diameter branch branch pipe (5). ), The nut (7) assembled on the side of the branch branch pipe is screwed into a screw hole formed on the inner peripheral surface of the joint fitting (4) to tighten and connect. Make up.

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

[0010]

As described above, the connection structure according to the present invention is based on the connection structure of the branch branch pipe (5) with the nut (7) at the joint fitting (4) fitted externally to the main pipe (1). This eliminates the need for brazing or fine welding at the connection with the branch branch pipe (5) at the time of connection, making it possible to easily connect the nut (7) by screwing and tightening, and to further improve the joint fitting (4). ), The entire peripheral surface of the main pipe (1) is engaged with the outer peripheral wall at the mounting hole, so that it is possible to sufficiently cope with an ultra-high flow pressure even under a vibrating state. This is a very useful connection structure, for example, with no fear of leakage of the branch and the detachment of the branch pipe (5).

[Brief description of the drawings]

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

FIG. 2 is a vertical cross-sectional view of FIG. 1 with a partial cutout.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main pipe 3 Through hole 3 'Pressure receiving seat surface 4 Joint fitting 5 Branch branch pipe 6 Pressing head 7 Nut

Claims (2)

(57) [Claims] 1. A thick and thin through-hole portion connected to a plurality of internal flow passages extending along the length of the thick-walled, thin-diameter main wall through which high-pressure fuel flows. In a connection structure in which branch branch pipes having diameters are connected in series, the inner periphery of the tip of each through hole (3) is formed as a conical or arcuate pressure receiving seat surface (3 ') that opens outward, and A joint fitting (4) made of a separate body is externally fitted to the outer peripheral wall of the main pipe (1) side surrounding the pressure receiving seat surface, and a branch branch pipe (5) is attached to the pressure receiving seat surface (3 '). In a state where a conical or arcuate pressing head (6) formed at the connection end and having a truncated cone shape is brought into contact with and engaged with the joint fitting (4), the nut (7) is incorporated into the branch branch. 3.) A connection structure for a branch branch pipe in a high-pressure fuel manifold, wherein the branch pipe is connected by being screwed into a screw hole of (2). 2. The coupling fitting (4) is a short annular body,
2. The connection structure for a branch branch pipe in a high-pressure fuel manifold according to claim 1, wherein the branch pipe is provided on an angular ring.