JPH084973A - Connecting structure of branch joint for high pressure manifold - Google Patents

Abstract

PURPOSE:To connect a branch joint to a main pipe without using welding or brazing, by opposing the distal end of the branch joint against an attaching hole in a first nut, and by screwing a second nut onto a second thread. CONSTITUTION:A first thread 16 having a large diameter is formed in a main joint pipe 4 which is attached to a main pipe 1 and which surrounds a pressure receiving seat surface 3' in the pipe 1. A first nut 7a having a large diameter is fastened onto a first thread 16, being opposed to the pressure receiving seat surface 3' in a gas-tight manner. This first nut 7a is axially formed therein with an attaching hole 20 in which a second thread 21 is formed. A branch pipe 5 is surrounded by the inner periphery of the attaching hole 20, being opposed against a press head part 6 of a press seat surface 17. A second nut 25 is inserted onto the branch pipe 5, and is screwed onto the second thread 2 so that a conical press seat surface 17 of the press head part 6 is opposed against a conical surface 22 of the attaching hole 20, thereby it is possible to secure the branch pipe 5 to the main pipe 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting structure of a branch connecting body such as a branch branch pipe or a branch fitting in a high pressure fuel manifold, and more particularly to a fuel supply passage to a diesel internal combustion engine.
The present invention relates to a connection structure of a branch connector in a high pressure fuel manifold of 00 kgf / cm ² or more.

[0002]

2. Description of the Related Art FIG. 5 is a side view including a cross-sectional view showing a connecting structure of a branch connector in a conventional high-pressure fuel manifold, in which a main passage 11 is formed with a flow passage 10 for circulating high-pressure fuel. A plurality of through holes 13 are formed in the axial direction with respect to the passage 10 (only one through hole 13 is shown in FIG. 5).

A contact surface 13a is formed on the main pipe 11 continuously from each through hole 13 in the outer peripheral direction.
The branch branch pipe 14 as a branch connection body is fitted into the main pipe 11 with the tip end a and the branch pipe 14 and the main pipe 11 connected to each other.
Are fixed at the connecting portion w by means of brazing or welding, and the flow passage 10 of the main pipe 11 and the flow passage 12 of the branch pipe 14 communicate with each other.

Conventionally, the high-pressure fuel manifold having such a structure branches the high-pressure fuel flowing through the flow passage 10 of the main pipe 11 from the flow passage 12 of the branch branch pipe 14 by each branch branch pipe 14.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-mentioned conventional connecting structure of the branch connector in the high-pressure fuel manifold, 1000
The ultra-high pressure flow of more than kgf / cm ² is repeatedly supplied, and vibration is further applied from the diesel internal combustion engine, so that a crack occurs in the connecting portion w, leakage such as fuel scattering occurs, and the branch branch pipe 14 is formed. I sometimes left.

Further, it is difficult to finish the facing surface 13a of the main pipe 11 into a predetermined curved surface with sufficient smoothness, which may cause fuel leakage or other leakage.

The present invention has been made in view of the present situation of the connection structure of this kind of branch connection body as described above, and the purpose thereof is to easily connect the branch connection body to the main pipe without using welding or brazing. It can be connected to each other, and the branch connector can be easily disassembled for storage and inspection. Also, when the branch connector is disassembled, the fittings can rotate or move axially with respect to the main pipe and become dusty inside. It is to provide a connection structure of a branch connector in a high-pressure fuel manifold that can prevent the intrusion of gas and the like, and the connection is not incomplete due to repeated supply of an ultra-high pressure flow or vibration from a diesel internal combustion engine. .

[0008]

To achieve the above object, according to the present invention, through holes are formed at a plurality of axial positions in a peripheral wall of a flow passage axially formed in a main pipe through which high-pressure fuel flows. A connecting structure of a branch connecting body in a high-pressure fuel manifold in which a branch connecting body having a flow path communicating with the flow passage is connected to the through hole, the main pipe communicating with the through hole, A pressure receiving seat surface that is open in the circumferential direction of the pipe is formed, and a first screw is formed in a joint fitting that is attached to the main pipe so as to surround the pressure receiving seat surface.
And a second nut is formed on the inner peripheral surface of the first nut so that the pressing seat surface is airtight to the pressure receiving seat surface. Mounting hole is provided in the axial direction, the branch-branch connecting body is inserted into the mounting hole, and the flow path of the branch-connecting body is communicated with the mounting hole of the first nut. The front end of the first nut is brought into contact with the bottom of the mounting hole of the first nut, the second nut is screwed into the second screw, and the branch connector is fixed to the main pipe. ing.

[0009]

According to the present invention, the first screw is formed in the joint metal fitting surrounding the pressure receiving seat surface of the main pipe and attached to the main pipe.
Nut is screwed onto the first screw. Since the screw surface of the first nut has a large diameter, a large thrust force can be obtained,
A high surface pressure is generated between the main pipe and the first nut, so that the pressure seat surface of the first nut is airtightly attached to the pressure seat surface. Since the pressure receiving seat surface has a relatively large diameter, a large correction moment acts on the first nut against the axial displacement of the first nut, and the pressing seat surface of the first nut moves against the pressure receiving seat surface. It is arranged in an airtight manner in a state where it is fully centered.

By screwing the first nut in this manner, the joint fitting, the main pipe and the first nut are preliminarily positioned at the correct positions, and the subsequent attachment and detachment of the branch connector becomes extremely easy. .

The branch connector is inserted through the mounting hole formed on the first nut and having the second screw formed on the inner peripheral surface thereof, and the second nut is screwed onto the second screw. A state in which the flow path formed in the branch connector is communicated with the mounting hole of the first nut by the second nut, and the tip of the branch connector is in contact with the bottom of the mounting hole of the first nut. It is attached to the main with.

The pressing seat surface of the first nut and the conical surface of the bottom portion of the mounting hole are turned into spiral cuts to improve the sealing performance.

In this manner, the first nut is air-tightly attached to the main pipe by being sufficiently centered, and the branch connection body is properly positioned by the second nut in the attachment hole of the first nut. Since the branch connector is attached to the main pipe in an airtight and highly accurate manner, the branch connector can be easily attached, and the branch connector can be easily disassembled. At the time of disassembly, the joint fitting is positioned and held with respect to the main pipe without rotating or moving in the axial direction, so that it is possible to prevent dust or the like from entering the inside.

[0014]

Embodiments of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, for example, an outer diameter of 20 mm,
A flow passage 2 is formed in a main pipe 1 made of a relatively thick metal pipe having a thickness of 6 mm, and a plurality of through holes 3 are formed in the longitudinal direction of the flow passage 2 and are continuous with the through hole 3. A pressure receiving surface 3'opened in the circumferential direction of the main pipe 1 is formed. The pressure receiving seat surface 3 ′ is formed in a curved surface forming a rotation surface centering on the axis of the through hole 3.

A joint metal fitting 4 is attached to the main pipe 1 so as to surround the pressure receiving seat surface 3 ', and a large diameter first screw 16 is formed on the joint metal fitting 4. The large-diameter first nut 7a is screwed onto the first screw 16 and is attached to the main pipe 1.
The conical pressing seat surface 18 formed at the tip portion is brought into contact with the pressure receiving seat surface 3 ′ via the seal member 19 and is hermetically attached.

The conical pressing seat surface 18 can be formed with a good sealing property by making a spiral cut by turning or the like.

A mounting hole 20 communicating with the flow passage 2 in the mounted state is formed in the first nut 7a in the axial direction.
A second screw 21 is formed on the inner circumference of the mounting hole 20.

A conical surface 22 having a good sealing property is formed by making a spiral cut on the inner periphery of the bottom of the mounting hole 20 by turning or the like.
The branch head 5 having the pressing head 6 formed at the end of the conical surface 22 and penetrating the flow path 5a makes the conical pressing seat surface 17 of the pressing head 6 abut. Are arranged. The second nut 25 is inserted into the outside of the branch pipe 5, and the second nut 25 is screwed into the second screw 21 to attach the conical pressing seat surface 17 of the pressing head 6 to the mounting hole. The branch branch pipe 5 is fixed to the main pipe 1 so as to be in contact with the conical surface 22 of 20.

As described above, according to the first embodiment, for the pressure bearing surface 3'which is relatively difficult to smooth and finish, the cone of the tip portion of the first nut 7a having a large diameter screw surface is used. In a state in which the pressing seat surface 18 in the shape of a ring is brought into contact with the seal member 19 to maintain airtightness between the main pipe 1 and the first nut 7a,
The first nut 7a can be sufficiently centered and attached to the main pipe 1 with a high surface pressure due to a large thrust force. The seal member 19 is not always required as long as the sealability between the pressure receiving surface 8'and the pressing seat surface 18 can be secured. Since the pressure bearing surface 3'has a large diameter during this mounting, even if the first nut 7a is misaligned,
A large correction moment acts on the nut 7a of the first nut 7a, and the first nut 7a is accurately centered and attached to the main pipe 1.

On the other hand, the conical surface 22 at the bottom of the mounting hole 20 of the first nut 7a and the pressing seat surface of the pressing head 6 of the branch pipe 5 can be easily processed by turning or the like. As a result, a spiral cut is generated to improve the sealing performance, so that the pressing seat surface 17 of the pressing head 6 and the conical surface 22 of the mounting hole 20 can be brought into contact with each other with high accuracy and improved sealing performance. Therefore, the branch branch pipe 5 is moved to the first nut 7 by screwing the second nut 25 into the second screw 21 while being accurately positioned with respect to the first nut 7a.
It can be fixed to a.

Therefore, according to the first embodiment, first of all,
The nut 7a is attached to the main pipe 1 in a state of being accurately centered, and then the branch branch pipe 5 is correctly positioned and fixed to the first nut 7a. With the branch pipe 5 properly positioned,
Since it can be attached airtightly, it can be easily disassembled by removing the nuts 25 and 7a at the time of maintenance and inspection, and the joint fitting 4 does not rotate or move axially when the branch branch pipe 5 is disassembled. It is possible to prevent dust and the like from entering the inside.

In the second embodiment, as shown in FIG. 2, the pressure receiving seat surface 3'a is made to be a horizontal plane continuous with the through hole 3 and is opposed to the pressure receiving seat surface 3'a as compared with the first embodiment. First nut 7
The pressing seat surface 18a of a is also made into a horizontal plane with good sealing property as a spiral cut by turning or the like, and a ring-shaped seal is provided between the pressure receiving seat surface 3'a and the pressing seat surface 18a of the first nut 7a as necessary. The material 19a is arranged.

Further, in the second embodiment, the branch connector is composed of the branch fitting 5 '. This embodiment uses a branch fitting such as an elbow, a pressure equalizing valve, a damping valve, a delivery valve and a discharge valve in order to avoid interference with other parts caused by a large curvature when bending the branch branch pipe. This is made in consideration of a case where a branch metal fitting internally having a mechanism such as a valve is used.

In the second embodiment, the branch connecting body connected to the main pipe 1 is composed of a branch fitting 5 ', and one end of the branch fitting 5'is pressed by a pressing head 6 in a conical shape as in the previous embodiment. Seat 1
8 and has a conical surface 22 provided at the bottom of the first nut 7a.
The second nut 25 is screwed into and brought into contact with and engaged with. On the other hand, the other end of the branch fitting 5'is connected to a branch branch pipe 5 "which is fixed by screwing a cap nut 27 through a sleeve 26.

According to the second embodiment, the branched branch pipe 5 ″ can be led out in parallel with the longitudinal direction of the main pipe 1.

The structure, operation and effect of the other parts of the second embodiment are the same as those of the first embodiment already described.

As shown in FIG. 3, in each embodiment, the packing member 30 is fixed by caulking to the pressing seat surface 17 of the pressing head 6 of the branch pipe 5 or the branch fitting 5'to further improve the sealing property. You can also let it.

Further, as shown in FIG. 4, in each embodiment, a resin coating 31 is applied to the pressing seat surface 17 of the pressing head 6 of the branch pipe 5 or the branch fitting 5 ', and the pressing seat of the pressing head 6 is provided. It is also possible to improve the contact sealability between the surface 17 and the conical surface 22 of the first nut 7a.

[0030]

As described in detail above, according to the present invention, the branch connection body can be fastened to the main pipe with two separate nuts, and the large diameter screw surface of the first nut can be used to make the branch connection body larger. Since a thrust force is generated and a high surface pressure is generated between the main pipe and the main pipe, it can be fixed in an airtight manner by a simple operation, and the branch connector can be easily disassembled for maintenance and inspection. At the same time, since the fittings do not rotate or move in the axial direction, it is possible to prevent dust and other foreign matter from entering the interior, and to prevent leakage of fuel due to repeated pressurization of the ultrahigh pressure fuel flow and vibration of the diesel internal combustion engine. It is possible to provide a connection structure of a branch connection body in a high-pressure fuel manifold that does not cause disconnection of the connection portion.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a second embodiment.

FIG. 3 is an enlarged sectional view of another embodiment of the branch connector.

FIG. 4 is an enlarged cross-sectional view of a branch connector according to still another embodiment.

FIG. 5 is a partial cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 main pipe 2 flow passage 3 through hole 3 ', 3'a pressure receiving surface 4 joint fitting 5 branch branch pipe 5'branching fitting 5a flow path 6 pressing head 7a first nut 16 first screw 17 pressing seat surface 18 pressing seat surface 18a pressing seat surface 19 seal member 19a ring-shaped seal member 20 mounting hole 21 second screw 22 conical surface 25 second nut 30 packing member 31 resin coating

Claims (2)

[Claims] 1. A through hole is formed at a plurality of axial positions in a peripheral wall of a flow passage formed in the main pipe in the axial direction and through which high-pressure fuel flows, and each of the through holes has a flow passage communicating with the flow passage. In the connection structure of the branch connecting body in the high-pressure fuel manifold in which the branch connecting bodies are continuously provided, the main pipe is formed with a pressure receiving surface that communicates with the through hole and is open in the circumferential direction of the main pipe. A first screw is formed on a joint fitting attached to the main pipe so as to surround the pressure receiving seat surface, and the first screw is screwed to the first fitting, and the pressing seat surface is attached to the pressure receiving seat surface. A first nut is attached so as to be airtight, and an attachment hole having a second screw formed on the inner peripheral surface is axially provided in the first nut, and the branch connection body is provided in the attachment hole. Is inserted, the flow path of the branch connection body is communicated with the mounting hole of the first nut, The tip of the branch connector is brought into contact with the bottom of the mounting hole of the first nut, the second nut is screwed onto the second screw, and the branch connector is fixed to the main pipe. The connection structure of the branch connector in the high-pressure fuel manifold. 2. A branch connector of a high pressure fuel manifold according to claim 1, further comprising a seal member interposed between the pressure receiving surface of the main pipe and the pressing seat surface of the first nut. Connection structure.