JPH11230438A - Common rail - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the more prefect sealing performance while preventing the generation of seizure and deformation of a metal by coating a pressure receiver seat surface part of a branch hole with the oil or performing the treatment for hardening the pressure receiver seat surface part with heat treatment, and thereafter, making a presser seat surface part of a branch pipe abut thereon for engagement. SOLUTION: A main pipe rail 1 as a common rail for diesel engine or the like is formed with a flow passage 1-1 inside of a core, and while formed with plural boss parts 1-4 with a space in the axial direction. Each boss part 1-4 is bores with a branch hole 1-2 communicated with the flow passage 1-1 and having a pressure receiver seat surface 1-3, and a presser seat surface part 2-3 of a connecting head part 2-2 of the branch pipe 2 is made to abut on the pressure receiver seat surface 1-3 of the main pipe rail 1 for engagement. In this case, the pressure receiver seat surface part 1-3 is coated with the oil or a part of the presser receiver seat surface 1-3 is hardened by quenching so as to prevent the generation of seizure and deformation at that part, and the excellent sealing performance is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates generally to common rails such as high pressure fuel manifolds or block rails in diesel internal combustion engines.

[0002]

2. Description of the Related Art Conventionally, as this kind of common rail, for example, those shown in FIGS. 1 to 5 are known.
The common rail shown in FIG. 1 communicates with a plurality of bosses 1-4 provided at intervals on an axial peripheral wall of the main rail 1 made of a circular pipe, and with a flow passage 1-1 of the main rail 1. ,
And a branch hole 1 having a pressure receiving seat surface 1-3 that opens outward.
2, and the pressing seat surface 2-3 formed by the connection head 2-2 on the branch pipe 2 side is brought into contact with the pressure receiving seat face 1-3 on the main pipe rail 1 side, and the connection is made in advance to the branch pipe side. The connection head 2 is screwed into the boss portion 1-4 with the built-in external screw nut 3 for fastening.
(2) There is known a system in which a connection is made by fastening together with pressing under a neck. In the figure, 2-1 is the flow path of the branch pipe 2, 4
Is a fastening sleeve washer.

The common rail shown in FIG. 2 has a plurality of bosses 11-4 provided at intervals on an axial peripheral wall of the main rail 11 made of a circular pipe, and a flow passage 11- of the main rail 11. Pressure receiving seat surface 11- which opens to the outside
3 is formed, and the pressing seat surface 12-3 formed by the connection head 12-2 on the branch pipe 12 side is connected to the main pipe rail 11.
The connection head is brought into contact with the pressure receiving seat surface 11-3 on the side, and a fastening cap nut 13 previously assembled on the branch pipe side via a washer 14 is screwed into the boss portion 11-4. Part 1
There is known a system in which a connection is made by tightening according to the pressing in 2-2. In the figure, reference numeral 12-1 denotes a flow path of the branch pipe 12.

Although FIGS. 1 and 2 illustrate a common rail having a boss portion integral with the main rail, the boss portion may be formed separately from the main rail.

A common rail shown in FIG. 3 is an internal flow passage 2 provided on a peripheral wall portion on the side of a main pipe rail 21 made of a circular pipe.
A pressure receiving seat surface 21-3 that opens outward from a branch hole 21-2 that communicates with the main hole 1-1 is provided on the main pipe rail 21 near the pressure receiving seat surface.
A cylindrical sleeve nipple 23 is attached to the outer peripheral wall of the main pipe rail 22 by a welding or brazing, and the pressure seating surface 22-3 formed by the connection head 22-2 of the branch pipe 22 is formed by the pressure receiving seat surface 2 of the main rail 21 side.
1-3, the sleeve nipple 23 and the tightening nut 24 previously assembled on the branch pipe side are screwed together with the connection head 22-2 and pressed down under the neck. A connection type is known. In the figure, 22-1
Is a flow path of the branch pipe 22.

The common rail shown in FIG. 4 is an internal flow passage 3 provided on the peripheral wall of the main pipe rail 31 made of a circular pipe.
A pressure receiving seat surface 31-3 that opens outwardly from a branch hole 31-2 that communicates with the main line 1-1, and the main pipe rail 31 near the pressure receiving seat surface is formed.
The use of the ring-shaped joint fitting 33 surrounding the outer periphery of the pipe 3 allows the end of the branch pipe 3 to be formed by buckling forming a conical tapered cone.
A pressing seat surface 32-3 formed by the second connection head 32-2 is brought into contact with and engaged with the screw wall 33-1 protruding from the joint fitting 33.
There is known a system in which a connection is formed by tightening together with a pressing under the neck of the connection head 32-2 by screwing a portion and a tightening nut 34 previously assembled on the branch pipe side. In the figure, 32
-1 is a flow path of the branch pipe 32, and 35 is a sleeve washer.

The common rail shown in FIG. 5 is an example applied to a block rail, and a connection hole 41 provided on the main rail 41 side.
-4, a branch hole 41-2 having a pressure receiving seat surface 41-3 communicating with the flow passage 41-1 of the main pipe rail 41 and opening outward is provided at the bottom of the connection head 42 on the branch pipe 42 side. -2, the pressure seat surface 42-3 formed on the main rail 41 side.
3 and is connected by tightening a tightening nut 44 screwed into the connection hole 41-4.

[0008]

However, the common rail as shown in FIGS. 1 to 5 has the following problems. That is, the branch pipes 2, 12, 22, 32, 42 and each The connecting portion with the pipe rails 1, 11, 21, 31, 41 is connected to the connecting head 1 of each branch pipe 2, 12, 22, 32, 42.
2, 12-2, 22-2, 32-2, 42-2, and the pressure receiving seat surfaces 1-3, 11-3, 21-3, 31-
The seal is made by the metal-to-metal contact caused by the axial force applied to 3, 41-3, but the contact part is pressed by a minute roughness part, deformed, and adheres to each other. This causes a problem that sealing is incomplete. Further, in the case of a common rail made of a soft metal, the internal pressure applied to the main rail is high and fluctuates. Therefore, a high axial force is generated to withstand this high and fluctuating internal pressure. There is a problem that the metal is deformed in the contact portion and the sealing is incomplete as described above. If the seal is incomplete, there is a possibility that the fluid leaks from the portion. Therefore, in order to prevent such a problem, it is necessary to prevent the above-mentioned seizure and deformation of the metal. However, in practice, no effective remedy has been taken for this problem.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a common rail which prevents seizure and deformation of a metal and has a more complete sealing performance.

[0010]

In order to achieve the above object, a common rail according to a first embodiment of the present invention comprises a main rail having a flow passage in an axial direction inside a main rail in an axial direction. A plurality of bosses provided at intervals are provided with a branch hole having a pressure receiving seat surface that opens to the outside and opens to the flow passage, and is provided at an end of a branch pipe having a flow passage communicating with the flow passage. A pressing seat surface formed by the provided connection head is brought into contact with and engaged with the pressure receiving seat surface, so that the boss portion is pressed under the neck of the connection head by screwing of a tightening nut previously assembled on the branch pipe side. In the common rail which is tightened and connected together, oil is applied to the pressure receiving seat surface portion of the branch hole, or at least one process of hardening the pressure receiving seat surface portion by heat treatment is performed, and the branch pipe side The pressing seat surface portion is brought into contact with and engaged with the pressing seat surface portion.

In a common rail according to a second embodiment of the present invention, a plurality of branch holes are provided at intervals in an axial peripheral wall portion of a main rail having a flow passage in an axial center thereof, and A pressure receiving seat surface is formed on a peripheral surface portion of the branch hole, the branch surface having a flow path communicating with the flow passage, and an outwardly open pressure receiving seat surface is formed to form a connection head provided at an end of the branch tube. The pressing seat surface portion is brought into abutting engagement, and the sleeve nipple attached to the main pipe rail by welding or brazing and a nut previously incorporated on the branch pipe side are screwed together with the pressing under the connection head neck. In the common rail which is fastened and connected, oil is applied to the pressure receiving seat surface of the branch hole, or at least one of treatments for hardening the pressure receiving seat surface by heat treatment is performed, and the pressure seat on the branch pipe side is performed. Characterized in that the surfaces are brought into abutment engagement.

In a common rail according to a third embodiment of the present invention, a plurality of branch holes are provided at intervals in an axial peripheral wall of a main rail having a flow passage in an axial center thereof, and A pressure receiving seat surface is formed on a peripheral surface portion of the branch hole, the branch surface having a flow path communicating with the flow passage, and an outwardly open pressure receiving seat surface is formed to form a connection head provided at an end of the branch tube. The pressing seat surface portion is brought into abutment engagement, and tightened with the pressing under the connection head by screwing a ring-shaped joint fitting surrounding the outer peripheral portion of the main pipe rail and a nut previously assembled on the branch pipe side. In the common rail which is attached and connected, oil is applied to the pressure receiving seat surface of the branch hole, or at least one of processing of hardening the pressure receiving seat surface by heat treatment is performed, and the pressure seat surface on the branch pipe side is performed. Are brought into contact with each other.

Further, in a common rail according to a fourth embodiment of the present invention, a plurality of branch holes are provided at intervals in a longitudinal peripheral wall portion of a block rail having a flow passage therein, and the branch hole is provided with a plurality of branch holes. A pressure seating surface that opens outward is formed by connecting a branch pipe having a flow path that communicates with the flow passage on the peripheral surface part, and a pressing seat surface part formed by a connection head provided at an end of the branch pipe is formed. It is brought into contact engagement, and tightened with a pressing under the connection head by screwing a connection hole provided in connection with the pressure receiving seat surface of the block rail and a nut previously assembled on the branch pipe side. In the common rail to be connected, oil is applied to the pressure receiving seat surface portion of the branch hole, or at least one process of hardening the pressure receiving seat surface portion by heat treatment is performed to abut the pressure seat surface portion on the branch pipe side. It is characterized by being engaged.

That is, the first feature of the present invention is that oil is applied to the pressure receiving seat surface of the branch hole to prevent the seizure of the pressure receiving seat surface on the main pipe rail side by the pressing force of the branch pipe side pressing seat surface. We are trying to prevent it. Here, the oil to be used may be any oil having lubricity, for example, an engine oil, a hydraulic oil, or the like, and is more preferably an oil or grease having heat resistance and containing an extreme pressure additive. is there. A second feature of the present invention is to prevent the deformation of the metal due to the internal pressure by hardening the pressure receiving seat surface by heat treatment, and quenching is generally used as the heat treatment. The hardness of the pressure-receiving seat portion for preventing large deformation of the pressure-receiving seat portion is not particularly limited, but at least Hv250 or more, preferably Hv350 or more is appropriate.

As described above, according to the present invention, it is possible to prevent seizure or deformation in the seal portion by lubricating the oil applied to the pressure receiving seat portion and / or increasing the hardness of the pressure receiving seat surface by heat treatment. And the sealing performance at the connection between the main pipe rail and the main pipe rail can be improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The common rail shown in FIGS. 1 to 5 will be described as an example. Main rails 1, 11, 21, 31, and 41 as common rails have a diameter of 28 mm, for example.
It is a steel pipe of material STS480 or a forged product of material S45C having a thickness of 9 mm and having a relatively thick tubular portion,
The inside of the shaft core is machined by a boring gun drill or the like so that the flow passages 1-1, 11-1, 21-1, 31-1, and
41-1 and a plurality of bosses 1-4, 11-4 or sleeve nipples 2 while maintaining an interval in the peripheral wall in the axial direction.
3, a ring-shaped joint fitting 33 or a connection hole 41-4 is provided.

The common rail shown in FIG. 1 has a plurality of bosses 1-4 provided at intervals on the peripheral wall in the axial direction on the main rail 1 side as described above.
1, a branch hole 1-2 having a pressure receiving seat surface 1-3 which is open outward is formed, and a pressing seat surface 2-3 formed by a connection head 2-2 on the branch pipe 2 side is connected to a main pipe. The connecting head 2 is brought into contact with the pressure receiving seat surface 1-3 on the rail 1 side, and the external thread nut 3 for tightening, which has been previously assembled on the branch pipe side, is screwed into the boss portion 1-4. In this common rail, oil is applied to a pressure-receiving seat surface 1-3 provided at an outer opening of the branch hole 1-2. Or hardening the portion of the pressure receiving seat surface 1-3 by, for example, quenching, or performing both treatments.

In the case of the common rail shown in FIG. 2, a pressure-receiving seat surface 11-3 which is provided at an outer end of a branch hole 11-2 which communicates with a flow passage 11-1 of the main pipe rail 11 and which is open outward is provided. In the case of the common rail shown in FIG. 3, an internal flow passage 21-1 provided on the peripheral wall portion on the side of the main pipe rail 21 made of a circular pipe.
In the case of a common rail shown in FIG. 4, the pressure receiving seat surface 21-3 is formed on the outer end of the branch hole 21-2 that communicates with the main rail 31. Hole 31-2 communicating with the internal flow passage 31-1
Pressure receiving seat surface 31-3 formed at the outer end of the cylinder and opening outwardly
In the case of the common rail shown in FIG.
The pressure receiving seat surface 41-formed at the outer end of the branch hole 41-2 provided at the bottom of the connection hole 41-4 provided on the side so as to communicate with the flow passage 41-1 of the main pipe rail 41. 3
Then, oil is applied, or the respective pressure receiving seat surface portions are hardened by quenching or the like, or both processes are performed.

As described above, the pressure receiving seat surfaces 1-3, 11-3, 21-3, 31-3, and 41- of the respective common rails.
In the case where oil or grease is applied to 3, the lubricating action of the applied oil or grease causes the pressing seat surfaces 2-3, 12-3, 22-3, 32-3, and 42- by press contact with the respective pressure receiving seat surfaces. 3
Is prevented, and the seal can be completely sealed.
When the pressure receiving seat surface 1-3 is hardened by quenching, even if a high internal pressure is generated in the main pipe rail 1, the pressure receiving seat surface 1-3 is hardened.
3 does not deform, so that high sealing performance can be obtained.

[0020]

As described above, the common rail according to the present invention has a high sealing performance by preventing seizure or deformation of the pressure receiving seat surface formed at the outer end of the branch hole and opening outward. Since it is obtained, there is an excellent effect that a stable function can be exerted reliably without fluid leakage.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a branch pipe connecting structure of a common rail having a boss portion to which the present invention is applied.

FIG. 2 is a longitudinal sectional view showing an example of a branch pipe connection structure portion of another common rail having a boss portion to which the present invention is applied.

FIG. 3 is a longitudinal sectional view showing an example of a branch pipe connecting structure of a sleeve nipple type common rail to which the present invention is applied.

FIG. 4 is a longitudinal sectional view showing an example of a branch pipe connection structure of a retainer type common rail to which the present invention is applied.

FIG. 5 is a longitudinal sectional view showing an example of a branch pipe connection structure of a block rail type common rail to which the present invention is applied.

[Explanation of symbols]

1, 11, 21, 31, 41 Main pipe rail 1-2, 11-2, 21-2, 31-2, 41-2 Branch hole 2, 12, 22, 32, 42 Branch pipe 3 External thread nut for tightening 4 Tightening sleeve washer 13 Tightening cap nut 14 Washer 23 Sleeve nipple 24, 34, 44 Tightening nut 33 Joint fitting 35 Sleeve washer

Claims (4)

[Claims] 1. A plurality of bosses provided at intervals in an axial peripheral wall portion of a main pipe rail having a flow passage in the axial center thereof, and open to the outside through the flow passage. A branch hole having a pressure receiving seat surface is provided, and a pressing seat surface portion formed by a connection head provided at an end of a branch pipe having a flow path communicating with the flow passage is brought into contact with and engaged with the pressure receiving seat surface, and the boss portion is formed. Oil is applied to the pressure receiving seat surface of the branch hole on the common rail which is tightened and connected together with the pressing under the connection head neck by screwing of the tightening nut previously incorporated in the branch pipe side. Alternatively, a common rail is characterized in that at least one of a process of hardening the pressure receiving seat surface portion by heat treatment is performed, and a pressing seat surface portion on the branch pipe side is brought into abutment engagement. 2. A plurality of branch holes are provided in an axial peripheral wall portion of a main rail having a flow passage in the axial center thereof with a space therebetween, and a plurality of branch holes are formed in a peripheral surface portion of the branch hole. Forming a pressure receiving seat surface that opens outward to connect a branch pipe having a communicating flow path, and abuts a pressing seat surface part formed by a connection head provided at an end of the branch pipe; A common rail which is fastened and connected together with a press under the connection head neck by screwing a sleeve nipple attached to the rail by welding or brazing and a nut previously incorporated on the branch pipe side, Oil is applied to the pressure receiving seat surface portion of the branch hole, or at least one of processing of hardening the pressure receiving seat surface portion by heat treatment is performed and the pressing seat surface portion on the branch pipe side is brought into contact with and engaged. Common rail. 3. A plurality of branch holes are provided at intervals in an axial peripheral wall portion of a main pipe rail having a flow passage in the axial center thereof, and each of said branch holes has a circumferential surface portion formed in said flow passage. Forming a pressure receiving seat surface that opens outward to connect a branch pipe having a communicating flow path, and abuts a pressing seat surface part formed by a connection head provided at an end of the branch pipe; A ring-shaped joint fitting surrounding the outer peripheral portion of the rail and located in the branch hole and a nut previously incorporated into the branch pipe side are tightened and connected together with the pressing under the connection head by screwing. In the common rail, the oil pressure is applied to the pressure receiving surface of the branch hole, or the pressure receiving surface is hardened by heat treatment, and the pressure receiving surface of the branch pipe is brought into abutment engagement. A common rail that is characterized by being hampered. 4. A plurality of branch holes are provided at intervals in a longitudinal peripheral wall portion of a block rail having a flow passage therein, and a flow passage communicating with the flow passage is provided on a peripheral surface of the branch hole. Forming a pressure receiving seat surface that opens outward to connect the branch pipes with each other, and abuts a pressing seat surface portion formed by a connection head provided at an end portion of the branch pipe so that the pressure receiving seat surface of the block rail is pressed. In a common rail which is tightened and connected together with a connection hole provided in continuation of the seat surface and a screw threaded between a nut previously assembled on the branch pipe side under the connection head, the pressure receiving of the branch hole A common rail, wherein at least one of a process of applying oil to a seat surface portion and a process of hardening the pressure receiving seat surface portion by heat treatment is performed so that a pressing seat surface portion on a branch pipe side is brought into abutment engagement.