JP2004174532A - Branch structure and face-to-face joining method for holder used for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a branch structure which is manufactured at cost, is suitable for mass production and is free from the possibility of a degradation in sealability between a main body and a branch pipe even when the pressure of an internal fluid is high. <P>SOLUTION: A holder 3 is face-to-face joined by a liquid phase diffusion joining method to the main body 1 having therein a flow passage 2. To a joint surface 7 compressive force by internal fluid pressure is applied. The branch pipe 5 is attached to the holder 3 and the tip of the pipe is brought into metal-to-metal touch with the main body 1. The holer can be face-to-face joined to the main body in the state of applying the compressive force to the joint surface of the main body and the holder by inserting a wedge-like tool to the side of the tip of the holder 3 opposite to the joint surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a branch structure used to constitute a piping system having a pipeline for fluid conveyance therein, and more particularly, to a pipeline system or a piping system of a pressure piping system or a fluid transportation system. The present invention relates to a branch structure as a constituent element and a surface joining method of a holder used for manufacturing the same.
[0002]
[Prior art]
[Patent Document 1] JP-A-2002-195125 [Patent Document 2] JP-A-2001-280218
In a piping system containing a carrier fluid, a piping system is often constructed with a branch structure having a function of taking the fluid from one direction and branching the fluid into a plurality of directions. Although there are many types of this branch structure, such as a Y-shaped one and a T-shaped one, it is considered that it is functionally almost equivalent to a T-shaped branch. Such a branch structure is referred to as a "tee" or "T-branch", and plays an important role in a conduit for a carrier fluid. In this specification, a branch structure having a role of branching a fluid flowing from one direction is generally referred to as a tee.
[0004]
By the way, when the fluid flowing inside the tee is a pressurized fluid, there is a stress concentration on the inner surface of the pipe at the time of branching. Alternatively, other material properties may be required. In particular, when the branch direction is perpendicular to the main body (main pipe) and the branched pipe (branch pipe) has a small diameter with respect to the main body, the tendency becomes strong. Therefore, a material and a structure different from the main body are often required for the tee, and the manufacturing technique is an important and difficult technique particularly in the pressure piping.
[0005]
For example, a steam reservoir (header) of a thermal power plant has a plurality of the tees arranged in parallel, and the diameter of the branch pipe may be about 1/10 of the diameter of the main body. As a specific example, a large number of small-diameter steel pipes having an inner diameter of 15 mm are vertically arc-welded to a steel pipe having an inner diameter of 100 mm. However, this header is a large-sized structure with a length of at least 5 m for collecting pipes and has a large working margin. In addition, since the steam, which is the carrier fluid, collects from small-diameter steel pipes and flows into the main body, the stress at the weld joints is reduced. It can be manufactured by arc welding because of the relatively low concentration.
[0006]
As described above, arc welding has been mainly used in the manufacture of tees, but when the fluid pressure is low, a method of integral molding by casting or the like is also adopted, and when the fluid pressure is high such as exceeding 1000 MPa. A method of shaving or drilling a forged product is adopted. However, in any case, there is a problem that the above-mentioned method for producing tea is not suitable for mass production and must be expensive.
[0007]
In addition, a branch structure called a common rail is used in a common rail fuel injection device of an engine. This distributes pressurized fuel to the injection nozzles of the engine, and a number of branch pipes are arranged vertically on the side surface of the main body. The above-mentioned Patent Document 1 discloses a common rail manufactured by a method of cutting the whole from a block. Since the common rail of Patent Document 1 does not have a welded joint, there is no risk of liquid leakage, but it is unavoidable that the manufacturing cost is extremely high.
[0008]
Patent Document 2 discloses a common rail in which a branch pipe and a main body are metal-touch-sealed by a cap nut type. The essential part of the common rail of this patent document 2 is as shown in FIG. 11, 50 is a main body, 51 is a branch member (holder) which is turned around the main body 50 and is welded to fillet, and 52 is a branch which is screwed to the branch member 51. Tube. The pressure of the fuel causes a stress load in the branch pipe 52 in a direction away from the main body 50, and whether or not the metal pipe surface 53 can withstand this and maintain the sealing property depends on the strength of the welded portion 54. For this reason, when the main body 50 and the branch member 51 are difficult-to-weld materials or are repeatedly subjected to fatigue stress, there is a possibility that the durability of the welded portion 54 decreases and the sealing performance becomes insufficient.
[0009]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has a low production cost and is suitable for mass production. In addition, even when the pressure of the internal fluid is high, there is no possibility that the sealing performance between the main body and the branch pipe is reduced. The present invention has been made to provide a surface bonding method of a structure and a holder used for manufacturing the structure.
[0010]
[Means for Solving the Problems]
A branch structure of the present invention made in order to solve the above-mentioned problem, a holder is joined to a main body having a flow path therein, and in a branch structure in which a branch pipe is attached to the holder, the main body and the holder are connected. It is characterized in that it is surface-joined on a surface that receives a compressive force due to internal fluid pressure. Preferably, the branch pipe mounted on the holder and the main body are sealed with a metal touch. Further, the branch structure of the present invention may be a common rail in which a plurality of branch pipes are provided vertically in a main body to which fuel is supplied. Alternatively, in addition to a common rail in which branch pipes are arranged in a single row, a plurality of rows may be provided, or a fluid collecting pipe in which pressure fluid is transferred from the branch pipe to the main body, for example, a header of a boiler which is a high-temperature pressure vessel. it can. The surface bonding between the main body and the holder is preferably liquid phase diffusion bonding.
[0011]
Further, in the method for bonding a holder of the present invention used for manufacturing the branch structure, a concave portion into which the tip of the holder is inserted is formed on an outer wall surface of a main body having a flow path therein, and the concave portion is inserted into the concave portion. The wedge-shaped jig is inserted on the opposite side to the joint surface at the tip of the holder, and the holder is surface-joined to the main body while compressive force is applied to the joint surface between the main body and the holder. .
[0012]
In the branch structure of the present invention, since the main body and the holder are surface-joined on a surface that receives a compressive force due to the internal fluid pressure, the strength and soundness of the joint are problematic unless the groove of the joint is destroyed. And the sealing performance between the branch pipe mounted on the holder and the main body is not impaired. According to the holder surface joining method of the present invention, the holder can be surface-joined to the main body in a state where the compressive force of the joint surface between the main body and the holder is applied, so that the branch structure of the present invention can be easily manufactured. It becomes.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
FIG. 1 is a cross-sectional view showing a first embodiment of a branch structure, wherein 1 is a main body having a circular cross section, and 2 is a flow path 2 of a pressurized fluid formed inside the main body 1. A holder 3 having a female screw 4 is fixed to an upper portion of the main body 1, and a branch pipe 5 is screwed into the holder 3.
[0014]
As shown in the figure, two V-shaped concave portions 6 are formed on both upper side portions of the main body 1, and two opposing upper planes of these concave portions 6 are joined to a joint surface 7 that extends toward the outer periphery of the main body 1. It has become. On the other hand, the distal end portion 8 of the holder 3 has a cross-sectional shape that can be inserted into these two V-shaped concave portions 6, and the inner surface of the distal end portion 8 is a flat surface that can be in close contact with the bonding surface 7. Then, at these joint surfaces 7, the main body 1 and the holder 3 are surface-joined.
[0015]
There are various types of methods for surface bonding of the bonding surface 7, such as brazing, which is the simplest method, diffusion brazing, liquid phase diffusion bonding, solid phase diffusion bonding, etc., and an arbitrary surface bonding method is adopted. be able to. However, it is advantageous to employ liquid phase diffusion bonding for bonding difficult-to-bond materials or dissimilar metal materials. In this liquid phase diffusion bonding, an alloy having a lower eutectic point than the material to be joined is supplied to the groove by means such as foil, powder, or plating, and the entire joint or the material to be joined is heated to the eutectic temperature or higher. Heating causes the molten metal to appear between the grooves and diffuses the element that forms the eutectic point, most often B or P, into the material to be joined, raising the melting point of the molten metal. This is a joining technology that forms a joint by realizing it.
[0016]
Since liquid phase diffusion bonding is surface bonding, the bonding time is constant irrespective of the bonding area, and since it passes through the liquid phase, unlike normal solid phase diffusion bonding, the bonding time is short and the necessary groove is required. It is characterized in that the application of stress to the surface is small. Furthermore, even in the case of a narrow groove having no gap into which a welding torch normally enters or a groove not opening to the outside, it can be applied by setting a heat source supply form to high-frequency induction heating or the like. Has advantages.
[0017]
On the other hand, from the supply form of the joining metal to the gap, it is necessary to have high processing and butting accuracy of the groove, the surface between the groove is a sufficient surface pressure, the state in which the liquid phase appeared, It must have been obtained during the isothermal solidification process. This means that, for example, when the temperature of the liquid phase diffusion bonding is set to 1100 to 1200 ° C., there is a very small portion where the contact pressure is not sufficient due to the hot plastic deformability and rigidity of the material to be bonded. This suggests that just performing a bonding defect will result in a bonding defect.
[0018]
However, as shown in FIG. 1, in the present invention, the inner side surface of the distal end portion 8 of the holder 3 and the bonding surface 7 of the main body 1 can be accurately butted, and liquid phase diffusion bonding can be employed. In particular, by employing the surface joining method described in claim 6, the joining can be performed with a sufficient surface pressure applied between the grooves. In this method, as shown in FIG. 9, a wedge-shaped jig 9 is inserted into the opposite side of the joint surface 7 at the tip of the holder 3 inserted into the concave portion 6 of the main body 1 to thereby form a joint surface 7 between the main body 1 and the holder 3. This is a method of performing surface joining while applying a compressive force to the surface. Although the tip angle of the wedge-shaped jig 9 is exaggerated in FIG. 9, the wedge-shaped jig 9 is also provided between the lower side surface 10 of the two V-shaped recesses 6 and the tip of the holder 3 in the branch structure of FIG. 1. This method can be adopted by forming a gap that can be inserted.
[0019]
It should be noted that there is no problem even if the same steel material as the material to be joined is used as the wedge-shaped jig 9, and austenitic steel can be used in view of a high expansion coefficient at a high temperature. In this case, although there is no particular limitation on the chemical components, it is necessary that the compound always has an FCC structure from room temperature to the bonding temperature and does not melt at a normal liquid phase diffusion bonding temperature of 1100 to 1200 ° C. The wedge-shaped jig 9 can be removed after joining, but may be left as it is when the tip of the jig is joined to the material to be joined by discharging the joining foil or when the structure of the material to be joined is beneficial. The wedge-shaped jig 9 does not necessarily need to be made of metal, but may be made of ceramics such as oxides, nitrides and carbides having high temperature rigidity, refractory bricks or the like, or fired products thereof.
[0020]
The branch pipe 5 is screwed into the holder 3 surface-joined to the main body 1 as described above. A tapered sealing surface 11 is formed at the tip of the branch pipe 5, and a metal touch seal is made in close contact with the conical concave surface on the upper surface of the main body 1. In this state, the branch flow path 12 formed inside the main body 1 communicates with the internal flow path 13 of the branch pipe 5. When the fluid flowing through these channels is a pressurized fluid, a force in the direction of separating the branch pipe 5 acts on the main body 1 by the internal fluid pressure, but in the branch structure shown in FIG. 1, and the fluid pressure therein acts to apply a compressive force to the joint surface 7. For this reason, a compressive stress acts on the joint surface 7 during use, and a tensile stress does not act unlike the conventional structure shown in FIG. Therefore, even when the pressure of the internal fluid is high, the sealing performance between the main body 1 and the branch pipe 5 does not decrease. Moreover, by combining the three parts, mass production can be performed at low cost.
[0021]
The compressive stress applied to the joint surface 7 is mainly caused by the internal pressure of the fluid as described above. However, when the holder 3 is, for example, a common rail, external stress due to vibration of an engine to which the holder 3 is attached, and when the header is a header, Compressive stress is also caused by an external force due to system stress caused by thermal expansion / contraction occurring in the entire piping system. The effect of the present invention is exerted on the stress caused by the external force as well as the internal pressure, and the stress separating the holder 3 from the main body can be converted into the compressive stress of the joint surface.
[0022]
In the second embodiment shown in FIG. 2, the tip of the holder 3 extends inward at a right angle, and the concave portion 6 of the main body 1 has a corresponding shape, but other configurations are the same as those of the first embodiment. And is common. In the second embodiment, the joint surface 7 between the main body 1 and the holder 3 is a plane perpendicular to the longitudinal direction of the branch pipe 5 (vertical direction in FIG. 2), and is preferably subjected to liquid phase diffusion joining. Also in this branch structure, since the joint surface 7 receives a compressive force due to the internal fluid pressure, the sealing performance between the main body 1 and the branch pipe 5 does not decrease even when the pressure of the internal fluid is high.
[0023]
In the third embodiment shown in FIGS. 3 and 4, concave portions 6 are formed on both side surfaces of the main body 1, and the tips of the holders 3 that are shaped to cover from above the main body 1 are bent inward and inserted into these concave portions 6. Have been. The joint surface 7 of the two is an inclined surface that expands outward in the direction of the branch pipe 5, and is also a joint surface 7 on which a compressive force acts by the internal fluid pressure. If the holder 3 is formed in a square shape as described above, the adhesion to the main body 1 can be further enhanced.
[0024]
In the fourth embodiment shown in FIG. 5, a holder 3 having a shape that wraps the main body 1 from the outside is used. In this case, the joining surface 7 is the lower surface of the main body 1 (the surface opposite to the branch pipe 5). 7, a compressive force is applied, and the sealing performance between the main body 1 and the branch pipe 5 does not decrease. With this structure, the area of the joint surface 7 can be made large, and the reliability can be further improved.
[0025]
FIGS. 6 and 7 show a fifth embodiment in which the present invention is applied to a common rail. Its cross-sectional structure is the same as that of the first embodiment shown in FIG. 1, and a plurality of holders 3 slidably fitted from the end faces on the upper surface of the elongated main body 1 are provided vertically, and the liquid Phase diffusion bonded. As shown in FIG. 7, a branch pipe 5 is screwed into each holder 3, and the distal end thereof is metal-sealed with the main body 1.
[0026]
The sixth embodiment shown in FIG. 8 is the same as that of the fifth embodiment except for the boiler header in which the main body 1 has a circular cross section. Such a header is a device for collecting and transporting the high-pressure fluid supplied from the flow path 2 to the main body 1, and the integrity of the joint surface 7 is impaired even when used under a state of receiving thermal stress. In addition, the sealability does not decrease due to the internal pressure of the fluid.
[0027]
FIG. 10 is a graph showing the fatigue characteristics of the structure of the present invention and the conventional product shown in FIG. As is clear from this graph, the branched structure of the present invention shows extremely excellent fatigue properties.
[0028]
【The invention's effect】
As described above, the branch structure of the present invention has an advantage that the manufacturing cost is inexpensive and suitable for mass production, and even when the pressure of the internal fluid is high, the sealing performance between the main body and the branch pipe is not reduced. As such, it is of high practical value as a tee, common rail or header. Further, according to the holder surface joining method of the present invention, surface joining can be easily performed in a state where a compressive force is applied to the joining surface, which is useful for manufacturing the branch structure of the present invention.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a first embodiment.
FIG. 2 is a cross-sectional view illustrating a second embodiment.
FIG. 3 is a sectional view showing a third embodiment.
FIG. 4 is a perspective view showing a third embodiment.
FIG. 5 is a sectional view showing a fourth embodiment.
FIG. 6 is a perspective view showing a fifth embodiment.
FIG. 7 is a sectional view showing a fifth embodiment.
FIG. 8 is a perspective view showing a sixth embodiment.
FIG. 9 is a cross-sectional view illustrating a method of bonding surfaces of the holder.
FIG. 10 is a graph showing fatigue characteristics of the product of the present invention and a conventional product.
FIG. 11 is a sectional view showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main body 2 Flow path 3 Holder 4 Female thread 5 Branch pipe 6 Depression 7 Joint surface 8 Tip 9 Wedge-shaped jig 10 Lower side surface 11 Seal surface 12 Branch flow path 13 Internal flow path 50 Main body 51 in the prior art Turn-filled Branch member 52 Branch pipe 53 Metal touch surface 54 Weld

Claims (6)

In a branch structure in which a holder is joined to a main body having a flow path therein, and a branch pipe is attached to the holder, it is required that the main body and the holder are surface-joined on a surface which receives a compressive force due to internal fluid pressure. Characteristic branch structure. The branch structure according to claim 1, wherein the branch pipe mounted on the holder and the main body are metal-touch sealed. The branch structure according to claim 1 or 2, wherein a plurality of branch pipes are provided vertically in a main body to which fuel is supplied, thereby forming a common rail. The branch structure according to claim 1, wherein a plurality of branch pipes are arranged in a plurality of rows in the main body, and a header for a pressure vessel configured to supply a pressure fluid from the branch pipe to the main body is configured. The branch structure according to any one of claims 1 to 4, wherein the surface bonding between the main body and the holder is a liquid phase diffusion bonding. A concave portion is formed on the outer wall surface of the main body having a flow path therein, into which the tip of the holder is inserted. A surface joining method of a holder, characterized in that a surface of a holder is joined to a main body while a compressive force is applied to a joining surface of the holder.

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