JPH04175462A - Connecting structure of branch connector in high pressure fuel block - Google Patents

Abstract

PURPOSE:To eliminate a deformation of the periphery of a pressure receiving seat surface, and to obtain an even surface pressure constantly, by specifying the position of the contact line between an almost spherical surface form of pressing seat surface at the top of a pressing head which is unitary with a branch connector screwed to a fuel block, and a pressure receiving surface, in respect of the width of the pressure receiving seat surface. CONSTITUTION:A branch pipe 5 furnishing a flow passage 20 as a branch connector is fastened square to the axial direction of a main pipe to compose a high pressure fuel of fuel block 1. A pressing head 6 is formed at the end of the branch pipe 5. To the tip of the pressing head 6, a regular spherical pressing seat surface 18 is formed. The branch pipe 5 is assembled to the fuel block 1 by squeezing a circular projection 20a through a sleeve 20c provided on the circular projection 20a, and fastening a nut 7 to a screw hole 16'. In this case, a contact line P of the pressing seat surface 18 and the pressure receiving seat surface 3' of the pressing head 6, and the distance lfrom the inner end of the pressure receiving seat surface 3' are set to the width W of the pressure receiving seat surface 3', within the scope 1/5W<l<9/10W, so as to suppress a deformation of the pressure receiving seat surface 3'.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a connection structure for branch connections such as branch pipes, branch fittings, etc. in a high-pressure fuel block, and particularly relates to a connection structure for branch connections such as branch pipes and branch fittings in a high-pressure fuel block, and in particular for fuel supply to diesel internal combustion engines. 101000st road
This invention relates to a connection structure of a branch connection body in a high pressure fuel block of /aJ or more. (Prior Art) FIG. 8 is a side view including a cross section showing a branch connection body in a conventional high-pressure fuel manifold, for example, a connection structure to a branch branch pipe, and shows a flow path through which high-pressure fuel flows into the main pipe 11. 10 is formed, and a plurality of through holes 13 are formed in the axial direction with respect to the flow passage 10 (only one through hole 13 is shown in FIG. 8). A branch pipe 14 is inserted and the branch pipe 14 and the main pipe 11 are fixed at a connecting part 15 by brazing or welding, and the flow path 1 of the main pipe 11 is fixed.
0 and the flow path 12 of the branch pipe 14 are communicated with each other.

(Problems to be Solved by the Invention) In the connection structure of the branch connection body in the conventional high-pressure fuel manifold described above, ultra-high pressure flow of 100,100 O/cJ or more is repeatedly supplied, and vibrations from the diesel internal combustion engine are also added. As a result, cracks may occur in the connection of the connecting portion 15 or in the heat-affected zone near the connecting portion 15, resulting in disassociation, fuel scattering and leakage, or separation of the branch pipe 14.

The present invention was made in view of the current state of the connection structure of this type of branch connection body as described above, and its purpose is to easily connect a branch connection body to a high-pressure fuel block without welding or brazing. High-pressure fuel that can obtain uniform surface pressure and connect while maintaining a firm seal, and that does not cause incomplete connections due to repeated supply of ultra-high pressure flow or vibrations from diesel internal combustion engines. The object of the present invention is to provide a connection structure for a branch connection body in a block.

(Means for Solving the Problems) ゛In order to achieve the above object, the present invention provides through holes at a plurality of positions in the axial direction in the peripheral wall of a flow passage formed in the axial direction in the fuel block and through which high-pressure fuel flows. formed so that the through-holes are connected with branch connectors each having a flow path communicating with the flow path,
A pressure receiving surface with an enlarged opening in the circumferential direction of the fuel block is formed, and a pressing head formed at the end of the branch connecting body is abutted and engaged with the pressure receiving surface, so that the branch connecting body side is brought into contact with the pressure receiving surface. ,
The branch connection body is fixed to the fuel block by screwing onto the fuel block side, and the abutting and engaging portion of the pressing head has a substantially spherical surface centered on the axis of the branch connection body. The abutting and engaging portion of the pressure receiving surface is formed into a
The receiving pressure is formed on a rotating surface centered on the axis of the through hole, and is at the intersection of a contact line between the spherical surface and the rotating surface and a surface passing through the axis of the through hole and parallel to the axial direction of the fuel block. The distance 1 from the inner end of the seat is set to 1/S W (41<9/10W, where W is the width of the pressure-receiving seat of the fuel block. Distance 1 is 1/4W) (1 (415W
is preferable, and more preferably 1/3 W <1 <3/4 W.

(Function) In the present invention, the contact line between the rotating surface of the pressure receiving surface formed at the abutting and engaging portion of the approximately spherical pressing surface at the tip of the pressing head and the pressing neck, and the through hole. The distance 1 from the inner end of the pressure-receiving surface of the intersection point passing through the axis and parallel to the axial direction of the fuel block is 115, where W is the width of the pressure-receiving surface of the fuel block.
Since W < J < 9/10W, there is no deformation of the periphery of the pressure bearing surface on the inner peripheral side in the press-sealed state, and no deformation occurs in the circumferential direction on the outer peripheral side of the pressure bearing surface. Uniform surface pressure is obtained, and accidents such as fuel scattering due to poor sealing performance are prevented.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 7.

Here, FIGS. 1(a) and (b) are explanatory views showing the contact state between the pressing head and the pressure-receiving seat in one embodiment, and FIG. 2 is a part showing the overall configuration of the embodiment in FIG. cross-sectional side view,
3 to 6 are sectional views showing main parts of other embodiments, FIG. 7(a) is a partially broken side view of still another embodiment, and FIG. 7(b) and (C ) are respectively shown in Figure 7(a).
FIG. 2 is a cross-sectional view and a front view taken along line B-B of the example.

First, as shown in FIG. 2, a branch branch pipe 5 having a flow path 20 as a branch connection body is fastened to a high-pressure fuel block 1 by a nut 7 at right angles to the axial direction of the main pipe 1.
It consists of A flow passage 2 is formed in the fuel block l, a through hole 3 is formed in this flow passage 2, and an axis of the through hole 3 that is enlarged and opened toward the outer circumferential surface of the main pipe 1 is formed at the end of the through hole 3. A conical pressure-receiving seat surface 3' is formed as a rotating surface around the core.

The above-mentioned through hole 3 has a conical pressure receiving surface 3° which forms a rotating surface around the axis of the through hole 3, and a communication hole 2 connected to the conical pressure receiving surface 3°.
The fuel block 1 has a straight hole 3"° opening to the fuel block 1, and a screw hole 16° extending from the through hole toward the outer circumferential surface of the fuel block 1.

A pressing head 6 is formed at the end of the branch pipe 5, and a spherical pressing seat surface 18 is formed at the tip of the pressing head 6. A circular annular protrusion 20a is formed at the upper part of the pressing seat surface 18.

In this state, with the pressing bearing surface 18 of the pressing head 6 of the branch pipe 5 facing the pressure receiving bearing surface 3°, a sleeve 20c is arranged on the annular protrusion 2Oa, and an annular shape is formed through the sleeve 20c. The branch pipe 5 is assembled to the fuel block 1 by tightening the nut 7 into the screw hole 16'' so as to press the protrusion 20a.

are pressed against each other, and the flow path 2 of the fuel block 1 is connected to the flow path 20 of the branch pipe 5 in an airtight manner. In this case, a sealing material such as a packing material such as copper may be interposed between the pressing head 6 and the pressure-receiving seat surface 3'.

In addition, as another embodiment, as shown in FIG.
The outer shape is formed into a substantially cylindrical shape, and the pressure bearing surface 18 that abuts and engages with the pressure receiving surface 3' is formed into a spheroidal surface centered on the axis of the flow path 20 of the branch pipe 5. The pressure receiving surface 3' is formed into a substantially spherical surface centered on the axis X of the through hole 3. The structure of other parts of this practical example is already the same as the structure of the embodiment shown in FIG.

In yet another embodiment, as shown in FIG. 4, the arrangement of the sleeve on the annular protrusion 2Oa is omitted, and the pressing head 6 has a conical outer shape cut at right angles to the axis of the tip. The pressing seat surface 18 is formed into a truncated conical surface centered on the axis of the channel 20 of the branch pipe 5. Further, the pressure receiving surface 3' is formed into a conical surface centered on the axis of the through hole 3.

The structure of other parts of this embodiment is already the same as the structure of the embodiment shown in FIGS. 2 and 3.

In the above-described embodiments, the pressure receiving surface 3' is a spherical surface and a conical surface, but this specification is not limited to these, and includes a parabolic surface of revolution, a hyperbolic surface of rotation, an ellipsoid of revolution, etc. Although the seat surface 18 is a true spherical surface, a spheroidal surface, and a truncated conical surface, the present invention is not limited to these examples, and may be a surface of rotation about the axis of the flow path 20. ,
For example, a parabolic surface of rotation, a hyperbolic surface of rotation, etc., or a combination thereof may be formed, and in this specification, all of these surfaces are defined as a "sphere".

By the way, in each example, FIGS. 1(a) and (b)
As shown in FIG.
The distance #iI from the inner end of the pressure bearing surface 3° of the intersection between the contact line P with the through hole 3 and the plane parallel to the axial direction of the fuel block 1 passing through the axis X of the through hole 3 is the distance #iI from the inner end of the pressure bearing surface 3°. The width of ° is 115
W (J (9/10W). If this distance p is less than 115W, the inner circumference am of the pressure receiving surface 3' of the through hole 3 will be easily deformed, especially the fuel block. If the fuel block 1 is designed to be lightweight and compact and the straight hole is short by 3', the axial direction side of the fuel block 1 at the peripheral edge will be deformed, making the seal incomplete and accidents such as fuel scattering likely to occur. In addition, when the distance p becomes 9/10W or more, deformation tends to occur in the circumferential direction on the outer circumferential side of the fuel block 1 at the pressure receiving surface of 3 degrees, the contact line length becomes longer, the surface pressure decreases, and the same as above occurs. Seal performance deteriorates and fuel scattering accidents are more likely to occur.

The present inventors set various distances 1 corresponding to widths W of 3° of various pressure-receiving surfaces, conducted experiments on changes in sealing performance, and obtained a basic value of 115 W (J (9/, 10 W)). We found that under the necessary conditions, the deformation of the pressure-receiving seat surface 3' is small, and therefore the variation in the circumferential direction of the width of the contact line P is also small. Even better sealing characteristics can be obtained by setting the conditions such that 1/3 W (1<415 W). did it.

In this way, the fuel block 1 passes through the contact line P between the pressing bearing surface 18 of the pressing head 6 and the pressure receiving bearing surface 3' and the axis X of the two through holes 3.
Since the distance 1 from the inner end of the pressure-receiving surface 3゛ of the intersection with the plane parallel to the axial direction of is set to the optimum range corresponding to the width W of the pressure-receiving surface 3゛, the pressure-receiving surface The deterioration of the sealing performance due to the deformation of the inner circumferential edge of the 3° or the circumferential deformation of the outer circumferential side of the pressure-receiving seat 3° increases the contact line length and reduces the surface pressure. is prevented.

In the above embodiment, the branch branch pipe 5 was shown as the branch connection body, but in the present invention, when bending the branch pipe 5, an elbow is used in order to avoid interference with other parts caused by a large curvature. The present invention can also be applied to the branch fitting 5° as shown in FIG. 5, taking into consideration the case where an equal pressure valve, damping valve, delivery valve, discharge valve, etc. are installed internally.

That is, one end of the branch fitting 5' has a pressing seat surface 18 formed into a substantially spherical surface as in the previous embodiment, and a screw 21 provided on the outer periphery of the branch fitting 5' is screwed into the screw hole 16 of the fuel block 1. By fitting, the pressure receiving surface 3' of the fuel block 1 is brought into abutting engagement, and the other end is provided with a bag via the sleeve 22.
This configuration is such that it is fixed by screwing the connector 23 and the branch pipe 5 is connected.

Furthermore, the present invention can also be used with a bag 24 as shown in FIG. A cylindrical protrusion 25 is formed in the center of the cap nut 24, and the inner circumferential screw 24 of the cap nut 24 is connected to the protruding wall 4 which is integrated with the fuel block 1 and protrudes in the radial direction. Outer circumference screw 16°.

This protrusion 25 causes the warasha 26 to
The annular protrusion 20a is pressed downward through the pressing seat surface 1.
8 is abutted and engaged with the pressure receiving surface 3°.

A projecting wall 4 integral with the fuel block 1 is provided outward in the radial direction of the fuel block 1, and within this projecting wall 4, a second design
Similarly, if a screw hole 16 is provided, the branch connection body can be fixed and connected to the fuel block using an ordinary slot 7, as shown in FIGS. 7(a) to (C). can.

In each of the embodiments described above, the pressing seat surface 18 of the pressing head 6 is substantially spherical, and is configured to make circular line contact with the pressure receiving surface 3', which is a rotating surface about the axis X of the through hole 3. Ru.

(Effects of the Invention) As explained in detail above, according to the present invention, even when repeatedly pressurized with an ultra-high pressure fuel flow or vibrations of a diesel internal combustion engine, there is no possibility of fuel splashing, leakage, or separation of connections. In particular, the distance of the contact line between the pressure bearing surface and the pressure bearing surface from the inner edge of the pressure bearing surface is set to an optimal range for the width of the pressure bearing surface of the fuel block, and the distance on the inner peripheral side of the pressure bearing surface is The peripheral edge of the pressure receiving surface is not deformed, and the outer circumferential side of the pressure receiving surface is not deformed in the circumferential direction, so uniform surface pressure is obtained and deterioration of sealing performance is completely prevented.・ .

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams showing the state of contact between the pressing head and the pressure-receiving seat in one embodiment of the present invention;
The figure is a partially cross-sectional side view showing the overall configuration of the embodiment shown in FIG.
3 to 6 are sectional views showing essential parts of other embodiments, FIG. 7(a) is a partially cutaway side view of still another embodiment of the present invention, and FIG. 7(b) and (C) are the seventh
FIG. 8(a) is a sectional view and front view taken along line B-B of the embodiment, and FIG. 8 is a side view including a sectional portion showing the structure of a conventional high-pressure fuel manifold. 1-...Fuel block, 2...-Flow path, 3...Through hole, 3゛...Pressure receiving surface, 5--Branch branch pipe, 5'...Branch fitting -16...Press Head, 7...-Natsuto, 16.
16゛...Screw hole, 18...Press bearing surface, 20a-...
- Annular protrusion. Patent applicant: Usui Kokusai Sangyo Co., Ltd. Figure 1 (a) Figure 1 (b) Figure 3? Figure 4 Figure 6 Figure 7 (b) Figure 7 (C)

Claims (3)

[Claims] (1) Through holes are formed at multiple positions in the axial direction in the peripheral wall of a flow passage formed in the axial direction in the fuel block and through which high-pressure fuel flows, and each of the through holes has a branch that has a flow passage leading to the flow passage. A pressure receiving surface with an enlarged opening in the circumferential direction of the fuel block is formed so that the connecting body is connected to the fuel block, and a pressing head formed at the end of the branch connecting body is brought into contact with the pressure receiving surface. The branch connection body is fixed to the fuel block by screwing the branch connection body side to the fuel block side, and the abutment engagement portion of the pressing head is configured to
The abutting and engaging portion of the pressure receiving surface is formed into a substantially spherical surface centered on the axis of the branch connection body, and the contact engagement portion of the pressure receiving surface is formed into a rotating surface centered on the axis of the through hole. The distance l from the inner end of the pressure bearing surface to the intersection of the contact line with the rotating surface and the plane passing through the axis of the through hole and parallel to the axial direction of the fuel block is determined by the pressure bearing surface of the fuel rail. 1 where the width of the surface is W
A connection structure of a branch connection body in a high-pressure fuel block, characterized in that /5W<l<9/10W. (2) In the connection structure of the branch connection body in the high-pressure fuel rail according to claim (1), 1/4W<l<4/5W
A connection structure of a branch connection body in a high-pressure fuel block, characterized in that the connection structure is set as follows. (3) In the connection structure of the branch connection body in the high-pressure fuel rail according to claim (1), 1/3W<l<3/4W
A connection structure of a branch connection body in a high-pressure fuel block, characterized in that the connection structure is set in a high-pressure fuel block.