JPH09280458A - Connection structure of branch connecting body in common rail - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute certain and stable connection without any leakage due to looseness, by arranging screw in a circulating pass side hole continued to a pressure receiving seat surface formed of the through-hole of a main pipe rail having a circulating pass inside a shaft core, and screwing a screw surface arranged at an end by being continued to a pushing/ pressing seat surface on a branch connecting body side to a screw on a rail side. SOLUTION: In a main pipe rail 1 as a common rail, the shaft core inside thereof is formed to serve as a circulating pass 1', and a plurality of opened through-holes 1" pressure receiving seat surface 2 having an interval in an axial circumferential wall, is arranged to be communicated with the circulating pass 1'. A screw 2' is formed in a circulating pass side hole continued to this pressure seat surface 2. A branch connecting body 3 has a channel 3' communicated with the circulating pass 1' in its inside, and a screw surface 4 is arranged by being continued to the pushing/pressing seat surface 3" of the end of branch connecting body 3, then the pushing/pressing seat surface 3" is brought into contact with the pressure receiving seat surface 2 following to screwing and tightening of this screw surface 4 to a screw 2' on a rail side 1. Also, a lock function can be obtained by screwing a nut 6 into a reverse screw surface 4' arranged in the upper part on the outside of the pushing/pressing seat surface 3".

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a connecting structure of a branch connecting pipe such as a branch branch pipe or a branch fitting in a common rail such as a high pressure fuel manifold or a block rail in a diesel internal combustion engine. .

[0002]

2. Description of the Related Art Conventionally, as a connection structure of this kind, as shown in FIG. 3, for example, a through hole (11) communicating with an internal flow passage (11 ') provided in a peripheral wall portion on the main rail (11) side. ″)
On the pressure-receiving seat surface (12) that is opened to the outside by using a joint fitting (14) that surrounds the outer peripheral portion of the main rail (11) near the pressure-receiving seat surface, the end portion is formed into a tapered conical shape. With the pressing seat surface (13 ″) formed on the side of the branch connector (13) having the expanded diameter portion (13 ′) in contact with and engaged with each other, the screw wall (14) protruding from the joint fitting (14). ′) To the branch connector (1
The mounting nut (15) incorporated on the side (3) is screwed and connected by being pressed by the enlarged diameter portion (13 '). Incidentally, (16) is a sleeve washer.

[0003]

However, in such a conventional connecting structure, since the surrounding joint fitting (14) is used, the weight of the product at the connecting portion is increased, and the branched connecting body is used. Due to the structure of the connecting head (13 ') whose diameter has been expanded by buckling in (13), an annular pocket portion (17) is created inside the head to increase the fuel flow resistance, and the nut. The direct screw-fastening structure of (15) has a problem that it causes loosening for a long period of time to induce leakage and make the connection unstable.

The present invention has been made in view of the above-mentioned problems of the prior art. The use of the surrounding joint metal fittings as in the prior art is not necessary at all, and the weight of the product is extremely reduced, and the branch connection is made. It does not require a diameter-expanded portion near the end formed by the body-side pressing seat surface, and the screwing and low-welding structure significantly enhances the mechanical strength of the vicinity.
A branch connector in a common rail that eliminates the anxiety of increasing fuel flow resistance, and at the same time eliminates leakage due to looseness at the mutual abutting and engaging parts for a long period of time, ensuring reliable and stable operation. It is intended to provide a connection structure of

[0005]

In order to achieve the above object, the present invention provides a plurality of through holes at intervals in the peripheral wall portion in the axial direction of a main rail having a flow passage inside the shaft core, and A pressure receiving seat surface is formed on the peripheral surface of the through hole, the branch seat having a flow path communicating with the flow passage, and a pressure receiving seat surface that is open to the outside is formed to contact the tapered conical pressing seat surface of the branch connector. In the connection structure in which the main rails are connected by being brought into close contact with each other, a screw portion is provided in a lower portion connected to the pressure receiving seat surface formed by the through hole of the main rail, and on the other hand, at the tip portion connected to the pressing seat surface on the branch connector side The gist of the present invention is to provide a connection structure of a branch connecting body in a common rail that is connected in an abutting engagement state by screwing with the screw portion on a provided screw surface, and further outside a pressing seat surface of the branch connecting body. The nut with the reverse screw surface is screwed on the upper part and the outer peripheral surface of the main rail Remembering stop function around and pressed engagement,
Further, a mutual screwing portion of the screw surface and the screw portion, a mutual engaging portion of the pressing seat surface and the pressure receiving seat surface, a screwing portion between the main rail and the reverse screw surface of the nut, or At least one of the engaging portions between the nut and the main rail is welded by brazing.

Since the present invention is constructed as described above, a reliable connection structure is formed by direct screwing and low welding between the main rail side and the branch connection body so that no joint metal fittings are enclosed. It is not necessary to make the product extremely lightweight, and the structure that does not require a diameter-expanded portion near the end of the pressing seat surface eliminates the need for molding and significantly improves the mechanical strength of the vicinity. It is possible to eliminate the anxiety of increasing the fuel flow resistance, etc., and to prevent leakage due to slack at the mutual abutting and engaging parts for a long period of time to obtain a reliable and stable connection. It will be possible.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of a connection state of a connecting structure of a branch connecting body in a common rail according to the present invention due to a partial cutout, FIG. 2 is a view corresponding to FIG. 2 showing another embodiment, in which (1) is a main rail as a common rail,
For example, a metal pipe having a thick and thin diameter of about 20 m / m and a wall thickness of about 8.0 m / m, and the inside of its axis serves as a flow passage (1 '), and a space is provided on the peripheral wall in the axial direction. A through hole (1 ″) that holds and forms an outwardly open pressure receiving seat surface (2) is provided through the flow passage (1 ′), and the flow passage (1 ′) is connected to the pressure receiving seat surface. ) A screw portion (2 ') is formed in the side hole portion.

On the other hand, (3) is a branch connecting body composed of a branch branch pipe or a branch fitting, and the flow passage (1 ') is provided inside.
And a threaded surface (4) is provided at the tip of the pressure bearing surface (3 ″) near the end of the pressure bearing surface (3 ″). The pressing seat surface (3 ″) is brought into abutting engagement with the pressure receiving seat surface (2) as the screw surface is screwed and fastened to the screw portion (2 ′) on the main rail (1) side. is there.

[0009] Then, in a corresponding contact engagement state, it is made of a metal brazing material such as copper, a copper alloy or the like in which the mutual engagement portion or the screwed portion, or both the mutual engagement portion and the screwed portion are provided in advance in the portion. The brazing material in the form of paste, ring or plating is melted by heat treatment and brazed (5) for connection.

Reference numeral (6) is a nut, which is screwed to a separate reverse screw surface (4 ') provided on the outer upper side of the pressing seat surface (3 ") of the branch connector (3) if desired. The lock function is provided to apply pressure to the outer peripheral surface of the pipe rail (1), and the lock function is exerted at the abutting engagement portion to prevent loosening, and as shown in FIG. Not only the mutual abutting engagement portion and the screwed portion formed by the pressure receiving seat surface (2) and the pressing seat surface (3 ″), but also the reverse screw surface of the main rail (1) and the nut (6) ( It is preferable that the threaded portion 4 ') and the pressure portion between the nut and the main rail (1) are further low-welded (5), because a more stable connection can be obtained.

[0011]

As described above, the connection structure of the branch connecting body in the common rail according to the present invention is directly connected to the screw portion (2 ') provided in the through hole (1 ") on the main rail (1) side. The threaded surface (4) connected to the pressing seat surface (3 ″) that does not require the expanded diameter portion formed on the branch connection body (3) side is screwed and tightened,
And preferably, the screw surface (4) and the screw portion (2 ') are mutually screwed together, the pressing seat surface (3) and the pressure receiving seat surface (2) are mutually engaged, and the main rail is provided. (1) and nut (6)
At least one of the screwed portion with the reverse screw surface (4 ') with the screw or the engagement portion between the nut (6) and the main rail (1).
Due to the structure that firmly and securely connects the two by low welding (5), it is possible to make the product extremely lightweight by eliminating the need for any additional fitting metal fittings surrounding the connection.
Further, it is possible to remarkably increase the mechanical strength near the end formed by the pressing seat surface (3 ″) and eliminate the anxiety of increasing the fuel flow resistance, etc., and further abut and engage each other for a long period of time. This is a very useful connection structure of a branch connection body in a common rail, such that leakage due to loosening at a portion can be eliminated and reliable and stable connection can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a connection state of a connection structure of a branch connection body in a common rail according to an embodiment of the present invention, the connection structure being partially cut away.

FIG. 2 is a view corresponding to FIG. 1 showing another embodiment.

FIG. 3 is an enlarged cross-sectional view of a connection structure of a branch connection body in a common rail showing a conventional example, with a partly cutaway.

[Explanation of symbols]

 1 Main rail 1 ″ Through hole 2 Pressure receiving seat surface 2 ′ Screw part 3 Branch connection body 3 ″ Pressing seat surface 4 Screw surface 5 Low welding

Claims (3)

[Claims] 1. A plurality of through holes are provided at an axial peripheral wall portion of a main rail having a flow passage inside a shaft core while maintaining a space therebetween, and a flow which leads to the flow passage is provided on a peripheral surface portion of the through hole. In a connection structure formed by forming a pressure receiving seat surface that is open to the outside for continuously connecting branch connecting bodies having a path and connecting the tapered conical pressing seat surfaces of the branch connecting bodies by abutting engagement with each other, Pressure bearing surface (2) formed by the through hole (1 ″) of the main rail (1)
The screw portion (2 ') is provided in the hole on the side of the flow passage extending to the above, and the screw surface (4) provided at the tip end is connected to the pressing seat surface (3 ") on the side of the branch connector (3). A connection structure of a branch connection body in a common rail, characterized in that the connection is configured in a contact engagement state by screwing with a screw portion (2 '). 2. A main rail (1) is engaged by screwing a nut (6) having a reverse screw surface (4 ') on the upper outside of the pressing seat surface (3 ") of the branch connector (3). The connection structure of a branch connection body in a common rail according to claim 1, wherein the connection structure has a detent function by pressing. 3. The threaded portion between the screw surface (4) and the screw portion (2 '), the engaging portion between the pressure seat surface (3) and the pressure receiving seat surface (2), and the book. Pipe rail (1) and nut (6)
At least one of the screwed portion with the reverse screw surface (4 ') with the screw or the engagement portion between the nut (6) and the main rail (1).
The connection structure of a branch connector in a common rail according to claim 1 or 2, wherein the two are low-welded (5).