JP4863255B2 - How to connect a branch connector to an accumulator - Google Patents

Description

  The present invention relates to a connection structure of a branch connection body by a branch branch pipe or a branch joint fitting in a cylindrical fuel accumulator vessel or a spherical fuel accumulator vessel such as a high pressure fuel manifold or a high pressure fuel block, particularly in a diesel internal combustion engine or the like. The present invention relates to an improvement in the connection structure of a branch connection body in a fuel pressure accumulator that supplies high-pressure fuel exceeding 100 MPa.

Conventionally, a cylindrical fuel pressure accumulating vessel having a cylindrical inner peripheral wall surface, as shown in FIG. 9, is connected directly or jointed to a cylindrical pressure accumulating vessel 111 whose inside is a flow passage with a branch branch pipe 112 as a branch connector. A configuration in which welding is connected through a metal fitting or the like is used. In the figure, 112-1 is a welding beat. Further, as the spherical fuel pressure accumulating vessel having a spherical inner peripheral wall surface, a branch branch pipe as a branch connecting body is directly or jointed to a spherical fuel container having a space having a spherical inner peripheral wall surface at least partially. The fuel accumulator vessel is connected via, for example.
In the connection structure as described above, a sudden change in supply pressure that is constantly repeated by a high-pressure fluid exceeding 100 MPa, especially a counterpart member (a counterpart seating surface due to vibration from the engine and an increase or decrease in ambient temperature) ) Due to the relative dimensional change between them, a large stress is generated at the pressure accumulating vessel opening end of the branch branch pipe or the branch joint fitting as the branch connection body, and the opening end is the starting point, and cracks are likely to occur. It often causes fuel leakage.
In general, as measures to increase the internal pressure fatigue strength of the open end of the pressure accumulator vessel of the branch connector, a method using high strength steel, a method of increasing material strength by heat treatment including carbonitriding, etc., forging the shape of the pressure accumulator vessel Means such as a type or an assembly type (eye joint type) is taken.
However, the method using high-strength steel for the branch branch pipe or branch joint fitting as the branch connection body has a problem in durability because the high-strength steel is very difficult to weld and cannot be hardened by heat treatment. Further, the method of increasing the material strength by heat treatment including carbonitriding has a drawback that it cannot withstand high pressure because the brazing material is deteriorated by the heat treatment and the strength cannot be increased. Furthermore, the forging and assembly types have the disadvantages of being heavy and expensive.

Improving the above-mentioned drawbacks, lowering the maximum stress value generated at the inner peripheral edge of the lower end of the branch branch pipe or branch joint fitting by inserting the branch connection body into the through hole provided in the peripheral wall portion of the pressure accumulating vessel, and reducing the internal pressure fatigue strength A connection structure as shown in FIG. 10 is disclosed as a connection structure of a branch connection body of a fuel pressure accumulating vessel that can be improved (see, for example, Patent Document 1). In the connection structure shown in FIG. 10, the flow path 111b is provided in the center of the cylindrical pressure accumulating vessel 111, and the connection end 112a of the branch branch pipe 112 having the flow path 112b in the center of the through hole 111c provided in the side wall. A connection structure is proposed in which the tip end 112c of the connection end 112a is protruded from the inner peripheral wall surface 111a of the pressure accumulating container to the inside of the container. In the figure, 112-1 is a brazing material.
In this connection structure, the end of the branch connection body consisting of the branch branch pipe or the branch joint fitting is inserted into the pressure accumulating vessel to form a protrusion and brazed to each other. As a result, the same internal pressure as the external pressure acts on the outer wall portion of the projecting portion to cancel both of them. As a result, the effect of significantly reducing the fatigue stress at the pressure accumulating vessel opening end of the branch connector is obtained. At the same time, a large pulling strength can be obtained by compressing the brazing filler metal and the diffusion bonding portion at the joint portion between the branch connection body and the pressure accumulating vessel by the internal pressure acting on the branch connection body. Accordingly, it is said that a high-pressure branch connection structure having high internal pressure fatigue characteristics can be provided at low cost even through a manufacturing process involving heat treatment such as brazing or diffusion bonding.
JP 2003-278623 A

However, in the above method, welding, brazing, or the like is used for connection between the pressure accumulating vessel main body and the branch connection body. For example, in the case of welding, there is a drawback that the metal structure of the welded portion becomes brittle, cracks or the like occur at the boundary of the structure, and cannot withstand high pressure. Also, when brazing, it is very difficult to secure the ideal brazing clearance, and the strength of the connecting part varies between the base metal strength and the brazing material strength. There is a concern that it is difficult to secure and various problems are likely to occur.
The present invention has been made to solve the above-mentioned problems, and does not use a brazing material that is expensive and is feared of a decrease in strength. The object of the present invention is to obtain a connection structure that is free from voids, has high strength at the joint, and is excellent in durability and reliability.

According to the connecting method of the branch connector in the pressure accumulating vessel of the present invention, the difference (d ₂ -d ₁ ) between the opening diameter d ₂ of the inner peripheral wall surface and the opening diameter d ₁ of the outer peripheral wall surface is at least one place in the accumulator vessel. A tapered through hole having a diameter of 02 to 0.04 mm is provided, and the diameter d ₁ of the minimum diameter portion is the same as the opening diameter of the outer peripheral wall surface of the through hole, and the diameter d _{2 of the} maximum diameter portion is It is the same as the opening diameter of the inner peripheral wall surface of the through hole, and the minimum diameter portion and the maximum diameter portion have a tapered shape having the same gradient as the through hole, and is opposite to the pressure storage container of the minimum diameter portion. A branch connection body having a flange is inserted by shrink fitting , and a wedge-shaped spacer is inserted and fixed between the flange and the pressure accumulating vessel surface .
According to this method, the branch connector can be brought into close contact with the through hole by driving a wedge-shaped spacer.

According to another connection method of the branch connector in the pressure accumulating vessel of the present invention, the difference (d ₂ −d ₁ ) between the opening diameter d ₂ of the inner peripheral wall surface and the opening diameter d ₁ of the outer peripheral wall surface is at least one place of the accumulator vessel. A tapered through hole having a diameter of 0.02 to 0.04 mm is provided, and after the pressure accumulating vessel is heated to 350 to 400 ° C., the diameter d ₁ of the smallest diameter portion is opened in the through hole on the outer peripheral wall surface of the through hole. is the same as the diameter, the diameter d ₂ of the largest diameter is the same as the opening diameter of the inner peripheral wall surface of the through hole, and a tapered shape outermost small diameter portion and the maximum diameter portion has the same slope as the through hole The branch connection body maintained at a low temperature of −50 to 0 ° C. is inserted by shrink fitting to return to normal temperature .
According to this method, the branch connection body can be brought into close contact with the through hole by fitting the branch connection body into the through hole using thermal expansion and cooling and contracting.

Furthermore, in the connection method of the branch connection body in the pressure accumulating vessel of the present invention, after the branch connection body is fitted into the through hole by the above method, a method of heating and holding at 700 ° C. or more in a reducing atmosphere is adopted. Can do.
According to this method, since the metallographic structure of the bonding surface forms a diffusion bonding in which the metal structures are integrated by thermal diffusion, a stronger connection can be achieved.

  According to the present invention, there is no direct diffusion bonding between the base materials without using welding that is likely to cause the metal structure to become brittle or cracking at the metal structure boundary, or a brazing material that is expensive and is feared to decrease in strength. Therefore, there is no occurrence of structural changes, micro cracks, and voids, the strength of the joint is increased, and a connection structure with excellent durability and reliability can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings.
First, a reference example of the present invention will be described.
FIG. 1 is a view showing a reference example of members constituting a connection structure of a branch connector in a pressure accumulating container according to the present invention, wherein (a) is an external view showing the vicinity of an insertion portion of the branch connector, and (b) is It is sectional drawing which shows the through-hole vicinity of a pressure accumulation container. Here, the branch joined body may be a branch branch pipe, or may be a branch joint fitting.
As shown in FIG. 1 (a), the branch connection body 1 used in the present invention is made of a pressure-resistant steel pipe, and the straight pipe portion 11 on the side opposite to the pressure accumulating vessel 2 and the straight pipe on the pressure accumulating vessel 2 side . It is comprised from the taper part 13 which connects between the parts 12. FIG. The diameter of the straight pipe portion 11 on the side opposite to the pressure accumulating container 2 is d ₁ , and the diameter of the straight pipe portion 12 on the pressure accumulating container 2 side is d ₂ , and has a tapered shape of d ₁ <d ₂ . The tapered portion 13 connects the straight pipe portion 11 on the opposite side of the pressure accumulator vessel 2 and the straight pipe portion 12 on the pressure accumulator vessel 2 side with a linear gradient, and the length L is substantially the same as the wall thickness t of the pressure accumulator vessel described later. It is configured. The taper portion 13 is a portion that is inserted into a through hole provided in a pressure accumulating vessel, which will be described later, and is tightly bonded. Therefore, the surface of the taper portion 13 is preferably finished by polishing or the like so that the average surface roughness Ra is about 12.5 μm to 3.2 μm.

The pressure accumulating vessel 2 used in the present invention is a vessel made of a pressure-resistant steel pipe having a thickness t as shown in FIG. 1 (b), and a through hole 23 that penetrates the outer peripheral wall surface 21 and the inner peripheral wall surface 22 thereof. Is provided. The outer peripheral wall surface 21 side of the inner diameter of the through-hole 23 is _{d 1,} the inner diameter of the inner peripheral wall surface 22 side is _{d 2.} These inner diameter d _1, d ₂ is the same as the diameter d ₂ of the diameter d ₁ and accumulating container 2 side of the straight pipe portion 12 of the previous branching connection body 1 of the accumulator container 2 opposite the straight pipe portion 11 cage, opening diameter d ₂ of the inner peripheral wall surface is set to slightly larger taper hole than the opening diameter d ₁ of the outer peripheral wall surface. Therefore, the gradient portion 13 of the branch connector 1 and the through-hole 23 of the pressure accumulating vessel 2 are precisely finished to the same dimensions of a short diameter d ₁ and a long diameter d ₂ at room temperature. The inner wall surface of the through hole 23 is preferably polished to an average surface roughness Ra of about 12.5 μm to 3.2 μm.

Next, a reference example of a method for forming the connection structure of the present invention by inserting the branch connector 1 into the through hole 23 will be described.
In this reference example, since the branch connection body and the through hole have the same taper shape, there is no problem when the pressure accumulation container is thick and the branch connection body can be inserted from the inside of the pressure accumulation container. However, in general, the branch connection body is often inserted from the outside of the pressure accumulating container.
When inserting the branch connector from the outside of the pressure accumulator uses shrink-fit technique of heating one to a high temperature. FIG. 2 shows the dimensional relationship of each part during shrink fitting.
If the coefficient of thermal expansion of the material constituting the branch connector and the through hole is β, and the heating temperature of the pressure accumulating vessel at the time of shrink fitting is T ° C., the opening diameter d ₁ of the outer peripheral wall surface of the through hole becomes D ₁ by thermal expansion. Swell. Inflated D ₁ of the time this must be greater than the diameter d ₂ of the accumulator vessel 2 side of the straight pipe portion 12 of the branch connection body. That is, it is necessary to satisfy d ₂ <D ₁ .
The relationship between D ₁ and d ₁ during shrink fitting is
D ₁ = d ₁ (1 + βT) (1)
It becomes. That is, the opening diameter D ₁ of the outer peripheral wall surface at the time of shrink fitting is proportional to the opening diameter d ₁ of the outer peripheral wall surface at the normal temperature. The larger than the value of D ₁ is (1), can be inserted branching connection body from the outside of the accumulator container by shrink fitting.
(1) from the equation, the ratio _D 1 / _{d 1} of _{D 1} and _{d 1} are
D ₁ / d ₁ = (1 + βT) (2)
Also, the difference between D ₁ and d ₁ (D ₁ -d ₁ ) is
D ₁ −d ₁ = d ₁ βT (3)
Thus, the difference between D ₁ and d ₁ (D ₁ −d ₁ ) is proportional to d ₁ . If thermal expansion and D ₁ of the case has is greater than the diameter d ₂ of the branching connection body pressure accumulator 2 side of the straight pipe portion 12 of, it is possible to shrink fit.
When shrink-fitting, if the branch connection body is kept at a lower temperature and the heating temperature of the pressure accumulating vessel is increased, the dimensional difference between the through hole and the branch connection body becomes larger, and therefore the fitting becomes easy.

To enable shrink fit, it is necessary to form a minor diameter d ₁ and the major axis d ₂ of the insertion portion of the through hole and the branch connection of pressure accumulator so as to satisfy the relation (1) above.
When the temperature is returned to room temperature after completion of shrink fitting, the diameters d ₁ and d _{2 of} the branch connector and the inner diameters d ₁ and d ₂ of the through holes of the pressure accumulating vessel are the same.
Usually, the thermal expansion coefficient β of the pressure-resistant high-strength steel constituting the pressure accumulating vessel or the branch connection body is about 1.3 × 10 ⁻⁵ / ° C., and the shrinkage working temperature T is about 350 ° C. to 400 ° C.
Now, the branched connecting body 1 made of pressure-resistant high-strength steel having a diameter d ₁ (= inner diameter on the outer peripheral wall surface 21 side of the through-hole 23 of the pressure accumulating vessel) of the straight pipe portion 11 on the opposite side to the pressure accumulating vessel 2 is When used, the diameter d ₂ of the straight pipe portion 12 on the pressure accumulating container 2 side (= the inner diameter on the inner peripheral wall surface 22 side of the through hole 23) is obtained. d ₂ need only be smaller than the D ₁ during the shrink fitting.
When d ₁ is 5 mm, substituting d ₁ = 5 mm, β = 1.3 × 10 ⁻⁵ / ° C., and T = 350 ° C. into Equation (3),
D ₁ −d ₁ = 5 × 1.3 × 10 ⁻⁵ × 350 = 22.75 × 10 ⁻³ ≈2.3 × 10 ⁻² (mm), that is, d ₂ is 0.023 mm larger than d ₁ It will be a good thing.
Similarly, when d ₁ is 10 mm, D ₁ −d ₁ = 10 × 1.3 × 10 ⁻⁵ × 350 = 3.6 × 10 ⁻² ≈4 × 10 ⁻² , that is, d ₂ is d If it is larger than ₁ by 0.04 mm, it will suffice.
If the branch connection body is kept at a low temperature of 0 ° C. to −50 ° C. using dry ice or liquid nitrogen, and the accumulator vessel is heated to a high temperature close to 400 ° C., even a fairly thick branch connection body can be easily and reliably obtained. A strong connection structure can be obtained by insertion.

From the above results, when the diameter of the straight pipe portion 11 on the side opposite to the pressure accumulating vessel 2 of the branch connector 1 is 5 to 10 mm, the diameter d ₂ of the straight pipe portion 12 on the pressure accumulator vessel 2 side of the branch connector 1. Is 0.02 to 0.04 mm larger than the diameter d ₁ of the straight pipe portion 11 on the side opposite to the pressure accumulating vessel 2, and the inner diameter of the through hole formed in the pressure accumulating vessel is also adjusted to the dimensions of the branch connector 1. , so that the inner diameter _{d 2} of the inner circumferential wall surface 22 side it is sufficient to 0.02~0.04mm larger than the inner diameter _{d 1} of the outer peripheral wall 21 side. Of course, in this case, it is important that the tapered portion of the branch connector and the inner peripheral wall surface of the through hole are finished to the same gradient.

In FIG. 3, a branch branch pipe is inserted as the branch connection body 1 into the through hole 23 of the pressure accumulating vessel 2 configured as described above, and the tapered portion 13 of the branch connection body 1 is shrink-fitted into the through hole 23 to be closely bonded. A reference example in the previous state is shown, and FIG. 4 shows a reference example in a state where the tapered portion 13 of the branch connector 1 is shrink-fitted and tightly joined.
In the state in which it was cooled to normal temperature after the shrink-fitting, the opening diameter d ₂ of the opening diameter d ₁ and the inner circumferential wall surface of the outer peripheral wall surface of the through-hole 23, respectively accumulator container 2 of the branch connection body 1 opposite to the straight pipe portion 11 is the same as the diameter _{d 2} of the straight tube portion 12 of a diameter _{d 1} and a pressure accumulator 2 side. Therefore, it is important to precisely finish the inner wall surface of the through hole 23 and the outer peripheral surface of the tapered portion 13 of the branch connector 1 at this time.
By adopting such a tapered connection structure, even if a high pressure is applied from the inside of the pressure accumulating vessel, a force in the direction of expanding the pressure accumulating vessel 2 from the tapered portion of the branch connection body 1 works, and the adhesion force is further increased. High-pressure contents do not leak from the section.
Further, according to this connection structure, since the heating temperature at the time of production is low, the metal structure is not fragile and cracks or the like are not generated at the boundary of the structure, so that a strong connection structure that can withstand high pressure can be obtained.
Furthermore, the difficult work of ensuring a delicate clearance is not required in the production work.

Next, examples of the present invention will be described.
FIG. 5: shows the external view which shows the insertion part vicinity of the branch connection body used in 1st Example of the method of connecting a branch connection body to the pressure accumulation container concerning this invention. The difference between the branch connector used in the first embodiment and the branch connector used in the reference example shown in FIG. 1A is the opposite side of the pressure accumulating container 2 at the smallest diameter portion of the branch connector 1. This is a point having a flange 14. The flange 14 is for inserting a spacer between the outer wall of the pressure accumulator vessel and forming a connection structure as will be described later, and further increasing the adhesion by using a tapered shape.
The dimensions of the diameter d ₂ of the diameter d ₁ and accumulating container 2 side of the straight pipe portion 12 of the accumulator container 2 opposite the straight pipe portion 11 of the branch connection body 1, because it is exactly the same as in the previous Example Description is omitted.

FIG. 6A shows a plan view of the spacer used in the first embodiment of the present invention.
The spacer 3 used in the first embodiment of the present invention has a cutout portion 31 in which a part of an annulus is cut out in plan projection, and the inner diameter R of the cutout portion 31 is the diameter of the smallest diameter portion of the branch connector. It is formed slightly larger than. The thickness of the view from the side when the spacer 3 as shown in FIG. 6 (b), the thickness t ₁ of the distal end side of the cutout portion 31 have become slightly thinner than the thickness t ₂ of the flat portion of the central It has a tapered part, and the central part is composed of parallel surfaces.
Figure 7 shows a cross-sectional view of a connecting structure definitive to the first embodiment using this spacer.
As shown in the figure, after inserting the branch connector 1 into the through-hole 23 of the pressure accumulator vessel 2, the spacer 3 is driven between the outer wall surface of the pressure accumulator vessel 2 and the flange 14 of the branch connector 1. Since the tip of the spacer 3 is gradually inclined so as to increase in thickness, when the spacer 3 is driven, a force that is pushed upward further acts on the branch connection body 1 to branch from the through hole 23 of the pressure accumulating vessel 2. The connection body 1 comes into close contact with the tapered portion 13 with a stronger pressure.
In this way, a strong connection structure that can withstand high pressure can be obtained.

In the second embodiment of the present invention, a branch joint fitting is used in place of a branch branch pipe as a branch connection body. FIG. 8 shows a cross-sectional view of the connection structure according to the second embodiment using a branch joint fitting.
As shown in the figure, the branch joint fitting 4 is composed of a neck portion 41 having a large outer diameter that protrudes from the outer wall surface of the pressure accumulating vessel 2, and a tapered portion 42 that is inserted into the through hole 23 of the pressure accumulating vessel 2. A flow passage 43 is perforated.
A pressure-receiving seat surface 44 whose peripheral edge opens in a conical shape is formed at the tip of the flow passage 43 on the neck 41 side, and is connected to a branch branch pipe (not shown). A screw thread 45 for fitting a cap nut for connecting and fixing the branch branch pipe is cut outside the neck portion 41. The tapered portion 42 is precisely machined to the same size as the through hole 23 of the pressure accumulating container 2 as in the case of the above-described reference example and the first embodiment of the present invention. That is, the dimension of the diameter d ₂ of the diameter d ₁ and accumulating container 2 side of the straight pipe portion 47 of the accumulator container 2 opposite the straight pipe portion 46 of the tapered portion 42 is completely the same as in the previous Example Since the relationship is satisfied to satisfy the expressions (2) and (3), the description is omitted.
After the branch joint fitting 4 is inserted into the through hole 23 of the pressure accumulator vessel 2, it is the same as that used in the case of the second embodiment between the outer wall surface of the pressure accumulator vessel 2 and the neck 41 of the branch joint fitting 4. Drive in the spacer 3. As a result, the through hole 23 of the pressure accumulating container 2 and the tapered portion 42 of the branch joint fitting 4 come into close contact with each other with a stronger pressure.
In this way, a strong connection structure that can withstand high pressure can be obtained.

In the third embodiment of the present invention, in the connection structure formed in the previous reference example and the first and second embodiments of the present invention, the joint surface of the through hole and the branch connector is integrally formed by thermal diffusion. .
That is, after the connection structure is formed as described in the reference example and the first and second embodiments of the present invention , the joint is heated to 700 ° C. or more in a reducing atmosphere to thermally diffuse the joint. Although the heating time depends on the heating temperature, it should be, for example, about 30 minutes at 850 ° C., and excessively high temperature or prolonged heating should be avoided in order to prevent embrittlement of the material.
An example of a reducing atmosphere is a non-oxidizing gas atmosphere of hydrogen: 11 vol%, carbon monoxide: 9 vol%, carbon dioxide: 7 vol%, nitrogen: 73 vol%, and dew point: 5-7 ° C.
By thermally diffusing the bonded portion, the metal structure is integrated to form a stronger bonded structure.

The inner diameter is 1.8 mm, the diameter of the straight pipe portion opposite to the pressure accumulator vessel 2 is 6.35 mm at the end, the diameter of the straight pipe portion on the pressure accumulator vessel 2 side is 6.39 mm, and the average surface roughness (Ra) is 3. A branched connection body made of a thick pressure-resistant steel pipe having a tapered portion having an outer surface of 2 to 12.5 μm was produced. A pressure accumulating vessel made of a thick pressure resistant steel pipe having an outer diameter of 30 mm and an inner diameter of 10 mm has an opening diameter of the outer peripheral wall surface of 6.35 mm, an opening diameter of the inner peripheral wall surface of 6.39 mm, and an average surface roughness (Ra) of 3.2. A through hole having an inner surface of ˜12.5 μm was provided.
In producing the connection structure, a flanged branch connection body and a spacer as shown in FIGS. 5 and 6 were used. The flange of the branch connection body was provided at a position where the clearance from the outer peripheral wall of the pressure accumulator vessel was 2.8 mm when fitted into the pressure accumulator vessel. Moreover, the thickness of the center part of the spacer was 3 mm, and the tip on the side of the notch part was thinned and processed into an inclined surface.

Insertion of the branch connector into the pressure accumulator was performed using shrink fitting. For shrink fitting, the accumulator was heated to 400 ° C., and the branch connector was cooled to 0 ° C. and inserted.
After inserting the branch connection body into the pressure accumulator vessel, a spacer was driven into the gap between the outer peripheral wall surface of the pressure accumulator vessel and the flange of the branch connection body, and the temperature was brought to room temperature.
Further, this connection structure was heated to 850 ° C. for 30 minutes in a non-oxidizing gas atmosphere of hydrogen: 11 vol%, carbon monoxide: 9 vol%, carbon dioxide: 7 vol%, nitrogen: 73 vol%, dew point: 6 ° C.
As a result, the metal structure of the joint was not fragile and cracks were not generated at the boundary of the structure, and a strong connection structure capable of withstanding high pressure was obtained, and the contents such as fuel did not leak.

It is a figure which shows the reference example of the member which comprises the connection structure of the branch connection body in the pressure accumulation container of this invention, Comprising: (a) is an external view which shows the insertion part vicinity of a branch connection body, (b) is the penetration of a pressure accumulation container It is sectional drawing which shows the hole vicinity. It is a figure which shows the dimensional relationship of each part at the time of shrink fitting in the structural member same as the above . It is a figure which shows the state before shrink-fitting a branch connection body to the through-hole of an accumulator container same as the above . It is a figure which shows the state which carried out shrink fitting of the branch connection body to the through-hole of the same pressure accumulation container. Is an external view showing an insertion portion near the branching connection body definitive to the first embodiment of a method of connecting a branch connection body according accumulator container present invention. It is a top view which shows the spacer concerning this invention . Also it is shown to cross-sectional view of the connecting structure definitive to the first embodiment of the present invention. It is sectional drawing which similarly shows the connection structure in 2nd Example of this invention. It is a figure which shows the connection structure of the branch connection body of the conventional fuel storage container. It is a figure which shows the other example of the connection structure of the branch connection body of the conventional fuel storage container.

DESCRIPTION OF SYMBOLS 1 Branch connection body 2 Accumulation container 3 Spacer 4 Branch joint metal fitting 11 , 46 Straight pipe part 12 on the opposite side to a pressure accumulation container , 47 Straight pipe part 13 on the pressure accumulation container side , 42 Taper part 14 Flange 21 Outer peripheral wall surface 22 Inner peripheral wall surface 23 Through hole 31 Notch 41 Neck 43 Flow passage 44 Pressure-receiving seat surface 45 Screw thread

Claims (3)

The difference between the opening diameter _{d 1} of the opening diameter _{d 2} and the outer peripheral wall surface of the inner peripheral wall surface in at least one place of the pressure accumulator _(d 2 -d ₁₎ is provided with a a tapered through hole 0.02~0.04mm is the same as the opening diameter of the outer peripheral wall surface of the diameter d ₁ of the minimum diameter portion to the through hole is the through hole, the diameter d ₂ of the largest diameter is the same as the opening diameter of the inner peripheral wall surface of the through hole, And the minimum diameter portion and the maximum diameter portion have a tapered shape having the same gradient as the through hole, and a branch connection body having a flange on the side opposite to the pressure storage container of the minimum diameter portion is inserted by shrink fitting , A method for connecting a branch connector in a pressure accumulating vessel, wherein a wedge-shaped spacer is inserted and fixed between the flange and the surface of the pressure accumulating vessel. The difference between the opening diameter _{d 1} of the opening diameter _{d 2} and the outer peripheral wall surface of the inner peripheral wall surface in at least one place of the pressure accumulator _(d 2 -d ₁₎ is provided with a a tapered through hole 0.02~0.04mm After the pressure accumulating vessel is heated to 350 to 400 ° C., the diameter d ₁ of the minimum diameter portion of the through hole is the same as the opening diameter of the outer peripheral wall surface of the through hole, and the diameter d _{2 of the} maximum diameter portion is the through hole. It is the same as the opening diameter of the inner peripheral wall surface of the hole, and the minimum diameter portion and the maximum diameter portion have a taper shape having the same gradient as the through hole, and is maintained at a low temperature of −50 to 0 ° C. A method of connecting a branch connection body to a pressure accumulating vessel, wherein the branch connection body is inserted by shrink fitting and returned to room temperature.   3. A method for connecting a branch connector to a pressure accumulating vessel, wherein the branch connector is connected to the pressure accumulating vessel by the method of claim 1 or 2 and then heated and maintained at 700 ° C. or higher in a reducing atmosphere.

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