JP2019167898A - Process of manufacture of fuel rail and fuel rail - Google Patents

Abstract

To provide a process of manufacture of fuel rail and the fuel rail manufactured by this process of manufacture, in which a stress concentration restriction location can be easily formed at a peripheral wall inner surface side of an open hole in respect to the fuel rail in which a cylindrical peripheral wall through which fuel can flow is formed with an open hole.SOLUTION: A process of manufacture of a fuel rail 40 provided with a cylinder 42 through which fuel flows is carried out in such a way that an open hole 50 is formed at a peripheral wall 43 of a cylinder 42 under application of a first cutting tool 60 and then a second cutting tool 62 is inserted into the open hole 50 from outside the cylinder 42, the second cutting tool 62 is rotated to cut an edge part of a peripheral wall inner surface 43A of the open hole 50 and then a diameter of a side of a peripheral wall inner surface 43A at the open hole 50 is expanded.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel rail manufacturing method and a fuel rail.

  Patent Document 1 discloses a method for manufacturing a common rail used in a fuel injection system of an internal combustion engine. In this manufacturing method, a flow passage is formed in the rail body portion, a branch passage branched from the flow passage is formed in the branch pipe portion formed integrally with the rail body portion, and then the abrasive is swirled in the flow passage. However, the edge of the entrance of the branch path located at the intersection of the flow path and the branch path is chamfered (blasting). The common rail manufactured by the above manufacturing method is suppressed from stress concentration at the branch path entrance located at the intersection of the flow path and the branch path.

JP 2008-88887 A

  In the manufacturing method disclosed in Patent Document 1, it is necessary to set a blast device to chamfer the edge of the branch path after forming the flow path and the branch path in the rail body and the branch section, and the common rail manufacturing process. Tends to be cumbersome.

  In view of the above facts, the present invention provides a fuel rail in which a stress concentration suppressing portion can be easily formed on the inner surface of the peripheral wall of the through hole with respect to the fuel rail in which the through hole is formed in the peripheral wall of the cylindrical body through which fuel can flow. It is an object of the present invention to provide a manufacturing method and a fuel rail manufactured by the manufacturing method.

  A fuel rail manufacturing method according to a first aspect of the present invention is a fuel rail manufacturing method including a cylindrical body through which fuel can flow, wherein a through hole is formed on a peripheral wall of the cylindrical body using a first cutting tool, A second cutting tool is inserted into the through hole from the outside of the cylindrical body, and the second cutting tool is rotated to cut an edge of the through hole on the inner surface side of the peripheral wall so that the inner surface side of the peripheral wall of the through hole is Increase the diameter.

In the fuel rail manufacturing method of the first aspect, first, a through hole is formed in the peripheral wall of the cylindrical body using the first cutting tool. Next, the second cutting tool is inserted into the through hole from the outside of the cylinder. And the 2nd cutting tool is rotated, the edge part of the surrounding wall inner surface side of a through-hole is cut, and the surrounding wall inner surface side of a through-hole is expanded. In this way, by expanding the diameter of the inner surface side of the peripheral wall of the through hole, that is, by forming an enlarged diameter portion (stress concentration suppressing portion) in the through hole, for example, the through hole has a cylindrical body as compared to a through hole. When a tensile force (expansion pressure) in the circumferential direction is applied, the concentration of tensile stress on the inner surface side of the peripheral wall of the through hole can be suppressed.
Here, in the manufacturing method described above, the inner diameter of the through hole can be increased by using the second cutting tool. Therefore, after the through hole is formed in the peripheral wall of the cylinder, the cylinder is made into another processing apparatus (for example, blasting). Compared with the manufacturing method set in the apparatus, a stress concentration suppressing portion can be easily formed on the inner surface side of the peripheral wall of the through hole. Furthermore, in the manufacturing method described above, it is not necessary to set the cylinder in another processing apparatus, so that the manufacturing time can be shortened.

  A fuel rail manufacturing method according to a second aspect of the present invention is the fuel rail manufacturing method according to the first aspect, wherein the second cutting tool includes a shaft portion and a cutting projecting radially outward from a tip portion of the shaft portion. The cutting portion is inserted into the through hole in a state where the axis of the shaft portion and the center of the through hole are shifted, and the axis of the shaft portion and the center of the through hole are made to coincide with each other. In this state, the shaft portion is rotated, and the edge portion of the through hole is cut by the cutting portion.

  In the fuel rail manufacturing method of the second aspect, the cutting part is inserted into the through hole in a state where the axis of the shaft part of the second cutting tool and the center of the through hole are shifted, and then the shaft center of the shaft part and the through hole are inserted. The shaft portion is rotated in a state where the centers of the holes are aligned, and the edge portion on the inner surface side of the peripheral wall of the through hole is cut at the cutting portion. In the above manufacturing method, the second cutting tool having a simple structure including the shaft portion and the cutting portion protruding radially outward from the tip portion of the shaft portion is used, and when the cutting portion is inserted into the through hole, The shaft center and the center of the through hole are shifted, and when cutting the edge on the inner surface side of the peripheral wall of the through hole at the cutting part, the shaft center is aligned with the center of the through hole. A stress concentration suppressing portion can be formed on the inner surface side of the peripheral wall of the hole.

  A fuel rail manufacturing method according to a third aspect of the present invention is the fuel rail manufacturing method according to the first aspect or the second aspect, wherein the cylindrical body is formed of a metal material, and the peripheral wall inner surface side of the through hole. After the diameter is expanded, a fuel rail component is brazed to the cylinder.

  In the fuel rail manufacturing method according to the third aspect, after the diameter of the inner surface of the peripheral wall of the through hole is increased, the fuel rail component is brazed to the cylinder. Here, in the above manufacturing method, the fuel rail components are brazed to the cylindrical body, and therefore, the manufacturing process of the fuel rail can be simplified as compared with, for example, a manufacturing method in which a flow passage or the like is formed in a casting by cutting.

  A fuel rail according to a fourth aspect of the present invention is a fuel rail manufactured by using the fuel rail manufacturing method according to any one of the first aspect to the third aspect. A cylindrical body in which a through hole is formed in the peripheral wall, the inner surface side of the through hole being larger in diameter than the outer surface side of the peripheral wall, and one end of the cylindrical body, and fuel is supplied to the cylindrical body and the cylindrical body A connecting portion for connecting a high-pressure pipe to be sent, a closed portion provided at the other end of the cylindrical body, and a closed portion for closing the other end; provided on an outer surface of the cylindrical body; And a housing to which a fuel injection member for supplying fuel to the fuel supply target by injection is attached.

  In the fuel rail of the fourth aspect, the diameter of the inner surface of the peripheral wall of the through hole formed in the cylindrical body is larger than that of the outer surface of the peripheral wall. That is, an enlarged diameter portion (stress concentration suppressing portion) is formed on the inner surface side of the peripheral wall of the through hole. For this reason, in the fuel rail, for example, when a through-hole formed in the cylinder has a constant diameter, when a circumferential tensile force (expansion pressure) acts on the cylinder, the inner surface of the peripheral wall of the through-hole It is possible to suppress the concentration of tensile stress on the side.

  As described above, according to the present invention, a fuel that can easily form a stress concentration suppressing portion on the inner surface side of the peripheral wall of the through hole with respect to the fuel rail in which the through hole is formed in the peripheral wall of the cylindrical body through which the fuel can flow. A rail manufacturing method and a fuel rail manufactured by this manufacturing method can be provided.

It is a perspective view of the fuel rail manufactured with the manufacturing method of the fuel rail concerning one embodiment of the present invention. It is a disassembled perspective view of the fuel rail shown in FIG. It is a top view of the cylinder which comprises the fuel rail shown in FIG. It is the 4X-4X sectional view taken on the line of the cylinder shown in FIG. FIG. 5 is a cross-sectional view of the cylinder shown in FIG. 2 taken along the line 5X-5X. It is the top view which looked at the surrounding wall inner surface of the cylinder shown in FIG. 5 from the arrow 6X direction. It is sectional drawing of the cylinder for demonstrating the manufacturing method of the fuel rail shown in FIG. 1, and has shown the operation | movement which forms a through-hole using the 1st cutting tool in a cylinder. It is sectional drawing of the through-hole periphery of a cylinder which shows the operation | movement which inserts a 2nd cutting tool in the through-hole of the cylinder formed in FIG. It is sectional drawing of the through-hole periphery of a cylinder which shows the operation | movement which makes the axial center of the 2nd cutting tool inserted in the through-hole in FIG. 8, and the center of a through-hole correspond. It is sectional drawing of the through-hole periphery part of a cylinder which shows the operation | movement which rotates the 2nd cutting tool inserted in the through-hole in FIG. 9, and cuts the inner edge part of the through-hole of a cylinder by a cutting part. FIG. 10 is a cross-sectional view of the periphery of the through hole of the cylindrical body showing an operation of extracting the second cutting tool from the through hole after the operation of FIG. 9. It is sectional drawing of the periphery of the through-hole of the cylinder which comprises the fuel rail which concerns on the other Example of this invention. It is sectional drawing of the periphery of the through-hole of the cylinder which comprises the fuel rail which concerns on the other Example of this invention. It is sectional drawing of the periphery of the through-hole of the cylinder which comprises the fuel rail which concerns on the other Example of this invention.

  Hereinafter, a fuel rail manufacturing method and a fuel rail according to an embodiment of the present invention will be described with reference to the drawings.

  First, the fuel rail 40 manufactured using the manufacturing method of the fuel rail of this embodiment is demonstrated. Next, a method for manufacturing the fuel rail 40 will be described.

<Fuel rail 40>
As shown in FIG. 1, the fuel rail 40 is a pressure accumulator used in a fuel supply system for supplying the fuel in the fuel tank 22 to the engine 20 of the automobile in a high pressure state. Specifically, the fuel in the fuel tank 22 is sent to the fuel rail 40 via the collective pipe 24 of the automobile, the high-pressure pump 26 and the high-pressure pipe 28 and is stored in the fuel rail 40 in a high-pressure state. The fuel in the fuel rail 40 is injected from the injector 30 connected to the fuel rail 40 into the cylinder 32 of the engine 20.

  As shown in FIGS. 1 and 2, the fuel rail 40 includes a cylindrical body 42, a connection portion 44, a closing portion 46, and a housing 48.

(Cylinder 42)
The cylinder 42 is formed of a metal material (for example, carbon steel, stainless steel, etc.). The inside of the cylindrical body 42 is a flow passage through which fuel can flow. A plurality of through holes 50 (see FIG. 5) are formed in the peripheral wall 43 of the cylindrical body 42 at intervals in the axial direction of the cylindrical body 42. As shown in FIG. 6, the through hole 50 is a round hole, and the hole portion 50 </ b> A located on the inner surface 43 </ b> A side of the peripheral wall 43 is larger in diameter than the hole portion 50 </ b> B located on the peripheral wall outer surface 43 </ b> B side. Specifically, as shown in FIG. 5, in the through hole 50, the hole diameter φA of the hole 50A is larger than the hole diameter φB of the hole 50B. Further, a step portion 50C is formed between the hole portion 50A and the hole portion 50B of the through hole 50 due to a difference in diameter. The step 50C is formed in parallel with the peripheral wall inner surface 43A. Specifically, as shown in FIG. 5, the distance L (the length along the radial direction of the cylindrical body 42 (circumferential wall 43)) L from the peripheral wall inner surface 43A to the stepped portion 50C is constant. Further, the hole wall surface of the hole 50A is parallel to the hole center HC.

(Connection 44)
The connecting portion 44 is provided at one end 42A of the cylinder 42 (the left end of the cylinder 42 in FIGS. 2 and 3). The connecting portion 44 is a part for connecting the cylindrical body 42 and the high-pressure pipe 28 that sends fuel to the cylindrical body 42. 1 to 14, the axial direction of the cylindrical body 42 is indicated by an arrow Y, and the radial direction of the cylindrical body 42 is indicated by an arrow R.

(Blocking part 46)
The blocking portion 46 is provided at the other end 42B of the cylinder 42 (the right end of the cylinder 42 in FIGS. 2 and 3). The closing portion 46 is a portion that closes the other end 42B of the cylindrical body 42 (see FIG. 4).

(Housing 48)
The housing 48 is provided on the outer surface 43B of the cylindrical body 42 (circumferential wall 43). The inside of the housing 48 communicates with the inside of the cylindrical body 42 through the through hole 50. For this reason, the fuel is fed into the housing 48 from the inside of the cylindrical body 42 through the through hole 50. An injector 30 is attached to the housing 48. The fuel in the housing 48 is supplied to the cylinder 32 of the engine 20 through the injector 30.

  The housing 48 is formed with a screw hole 48A. A mounting bolt 34 that passes through a through hole of a mounting bracket (not shown) is screwed into the screw hole 48A.

  Further, a cylindrical receiving portion 52 is formed on the other end 42 </ b> B side of the cylindrical body 42. The inside of the receiving portion 52 communicates with the inside of the cylinder body 42 through a through hole 51 (see FIG. 4) formed in the cylinder body 42. As shown in FIG. 1, a pressure sensor 36 (see FIG. 2) for measuring the fuel pressure in the cylindrical body 42 is attached to the receiving portion 52. The through hole 51 of the cylindrical body 42 is a round hole, like the through hole 50, and the diameter of the hole located on the inner surface 43A side of the peripheral wall 43 is larger than the diameter of the hole located on the outer peripheral surface 43B side. ing.

  The fuel rail 40 of the present embodiment is integrally formed by brazing the cylindrical body 42, the connecting portion 44, the closing portion 46, the housing 48, and the receiving portion 52, which are fuel rail components.

<Method for Manufacturing Fuel Rail 40>
Next, the manufacturing method of the fuel rail 40 of this embodiment is demonstrated.

  First, a cylindrical body 42 made of a metal material is prepared and set in a cutting device (not shown).

  Next, as shown in FIG. 7, a through hole 50 is formed in the peripheral wall 43 of the cylindrical body 42 using a first cutting tool 60 (for example, a drill). After the through hole 50 is formed, the first cutting tool 60 is pulled out from the through hole 50.

  Next, as shown in FIGS. 8 to 11, a through hole is formed using a second cutting tool 62 including a shaft portion 64 and a cutting portion 66 protruding radially outward from a tip portion 64 </ b> A of the shaft portion 64. Cutting is performed on the edge of the peripheral wall inner surface 43A side of 50. Specifically, as shown in FIG. 8, the axial center AC of the shaft portion 64 of the second cutting tool 62 and the hole center HC of the through hole 50 are shifted from the outside of the cylindrical body 42 to the through hole 50. The cutting part 66 of the second cutting tool 62 is inserted. After the cutting part 66 passes through the through hole 50, as shown in FIG. 9, the shaft part 64 is moved so that the axial center AC of the shaft part 64 and the hole center HC of the through hole 50 coincide. Next, as shown in FIG. 10, the shaft portion 64 is rotated in a state in which the axial center AC and the hole center HC coincide with each other, and the edge portion on the peripheral wall inner surface 43 </ b> A side of the through hole 50 is cut by the cutting portion 66. The diameter of the peripheral wall inner surface 43A side of the through hole 50 is increased.

After cutting the edge of the through-hole 50 on the peripheral wall inner surface 43A side, as shown in FIG. 11, the axial center AC is moved to displace the axial center AC and the hole center HC. Pull out from the through hole 50. Thereby, the through-hole 50 formed in the cylinder 42 has the hole part 50A, the hole part 50B, and the step part 50C.
Then, the through hole 51 is formed in the peripheral wall 43 in the same procedure as the procedure for forming the through hole 50 in the peripheral wall 43.

  Next, the fuel rail components (connecting portion 44, closing portion 46, housing 48, receiving portion 52) are brazed to the cylindrical body 42. Thereby, the cylinder 42, the connection part 44, the obstruction | occlusion part 46, the housing 48, and the receiving part 52 are shape | molded integrally.

  Next, the method for manufacturing the fuel rail and the function and effect of the fuel rail 40 according to this embodiment will be described.

  As described above, in the method of manufacturing the fuel rail 40, first, the through hole 50 is formed in the peripheral wall 43 of the cylindrical body 42 using the first cutting tool 60, and then the through hole 50 is used using the second cutting tool 62. The edge part of the peripheral wall inner surface 43A side is cut, and the diameter of the peripheral wall inner surface 43A side of the through hole 50 is increased. Thus, by enlarging the diameter of the peripheral wall inner surface 43 </ b> A side of the through hole 50, that is, by forming a hole portion 50 </ b> A (stress concentration suppressing portion) larger than the hole portion 50 </ b> B in the through hole 50, for example, the through hole 50 As compared with a constant diameter, when a tensile force (expansion pressure) in the circumferential direction is applied to the cylindrical body 42, the concentration of tensile stress on the side of the inner surface 43A of the through hole 50 can be suppressed. In other words, the tensile stress generated on the peripheral wall inner surface 43A side of the through hole 50 can be dispersed.

  Further, in the above manufacturing method, since the diameter of the peripheral wall inner surface 43A side of the through hole 50 can be increased using the second cutting tool 62, after the through hole 50 is formed in the peripheral wall 43 of the cylindrical body 42, the cylindrical body is subjected to other processing. Compared with the manufacturing method set in a device (for example, a blast device), the hole portion 50A, which is a stress concentration suppressing portion, can be easily formed on the side of the inner surface 43A of the through hole 50. Furthermore, in the manufacturing method described above, it is not necessary to reset the cylindrical body 42 to another processing apparatus, so that the manufacturing time can be shortened.

  In the manufacturing method described above, the cutting portion 66 is inserted into the through-hole 50 in a state where the axial center AC of the shaft portion 64 of the second cutting tool 62 and the hole center HC of the through-hole 50 are shifted, and then the axial center of the shaft portion 64. The shaft part 64 is rotated in a state where the AC and the hole center HC of the through hole 50 are aligned, and the edge part on the peripheral wall inner surface 43 </ b> A side of the through hole 50 is cut by the cutting part 66. In the manufacturing method described above, the second cutting tool 62 having a simple structure including the shaft portion 64 and the cutting portion 66 protruding radially outward from the tip portion of the shaft portion 64 is used. Is inserted into the axial center AC of the shaft portion 64 and the hole center HC of the through hole 50 is shifted, and when the cutting portion 66 cuts the edge of the through hole 50 on the peripheral wall inner surface 43A side, the shaft of the shaft portion 64 is inserted. The hole 50A, which is a stress concentration suppressing portion, can be formed on the side of the peripheral wall inner surface 43A of the through hole 50 by a simple operation of matching the center AC with the hole center HC of the through hole 50.

  Further, in the above manufacturing method, after the hole portion 50A is formed in the through hole 50, the fuel rail components (connecting portion 44, closing portion 46, housing 48, receiving portion 52) are brazed to the cylindrical body 42. Here, in the above manufacturing method, the fuel rail components are brazed to the cylindrical body 42. Therefore, the manufacturing process of the fuel rail can be simplified as compared with, for example, a manufacturing method in which a flow passage or the like is formed in a casting by cutting. .

  In the fuel rail 40 manufactured by the above manufacturing method, as described above, when a circumferential tensile force (expansion pressure) acts on the cylinder, the tensile stress concentrates on the side of the peripheral wall inner surface 43 </ b> A of the through hole 50. It is suppressed. For this reason, generation | occurrence | production of a malfunction is suppressed for the said fuel rail 40 over a long period of time.

  In the above embodiment, as shown in FIG. 5, the hole wall surface of the hole 50A of the through hole 50 is parallel to the hole center HC, but the present invention is not limited to this configuration. For example, the hole wall surface of the hole portion 70A may be inclined with respect to the hole center HC as in the through hole 70 shown in FIG. 12, or the hole portion as in the through hole 72 shown in FIG. The hole wall surface of 72A may be curved in an arc concave shape with respect to the hole center HC. The through hole 70 is formed by a hole portion 70A on the peripheral wall inner surface 43A side, a hole portion 70B on the peripheral wall outer surface 43B side, and a step portion 70C. The through-hole 72 is formed by a hole 72A on the peripheral wall inner surface 43A side, a hole 72B on the peripheral wall outer surface 43B side, and a stepped portion 72C.

  In the above-described embodiment, as shown in FIG. 5, the through hole 50 is formed by the hole portions 50A and 50B and the step portion 50C. However, the present invention is not limited to this configuration. For example, a plurality of hole portions 74A, 74B, and 74C and step portions 74D and 74E may be formed as in the through hole 74 shown in FIG. The hole 74A is located closest to the inner surface 43A of the peripheral wall, and has a larger diameter than the holes 74B and 74C. As described above, the tensile stress can be dispersed in a plurality of stages by increasing the diameter of the through hole 74 stepwise toward the peripheral wall inner surface 43A side.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

20 Engine (subject to fuel supply)
28 High-pressure piping 30 Injector (fuel injection member)
40 fuel rail 42 cylinder 42A one end 42B other end 43 peripheral wall 43A peripheral wall inner surface 43B peripheral wall outer surface 44 connection portion 46 closing portion 48 housing 50 through hole 50A hole portion (inner wall inner surface side of through hole)
50B hole (outer wall outer surface side of the through hole)
51 Through-hole 60 First cutting tool 62 Second cutting tool 64 Shaft portion 64A Tip portion 66 Cutting portion 70 Through-hole 70A Hole portion (the inner surface side of the peripheral wall of the through-hole)
70B hole (on the outer wall side of the through hole)
72 through hole 72A hole (inner wall inner surface side of the through hole)
72B hole (outer wall side of through hole)
74 through hole 74A hole (inner wall inner surface side of the through hole)
74C Hole (Outside surface of the peripheral wall of the through hole)
AC shaft center (axis of the shaft part of the second cutting tool)
HC hole center (center of through hole)

Claims (4)

A method of manufacturing a fuel rail comprising a cylinder through which fuel can flow,
A through hole is formed on the peripheral wall of the cylindrical body using the first cutting tool,
A second cutting tool is inserted into the through hole from the outside of the cylindrical body, and the second cutting tool is rotated to cut an edge of the through hole on the inner surface side of the peripheral wall so that the inner surface side of the peripheral wall of the through hole is A fuel rail manufacturing method for expanding the diameter. The second cutting tool includes a shaft portion, and a cutting portion protruding radially outward from a tip portion of the shaft portion,
The cutting part is inserted into the through hole in a state where the axis of the shaft part and the center of the through hole are shifted, and the shaft part is aligned with the axis of the shaft part and the center of the through hole being aligned. The method of manufacturing a fuel rail according to claim 1, wherein the edge of the through hole is cut by the cutting portion by rotation. The cylinder is made of a metal material,
The fuel rail manufacturing method according to claim 1 or 2, wherein a fuel rail component is brazed to the cylindrical body after the inner diameter side of the peripheral wall of the through hole is expanded. A fuel rail manufactured using the fuel rail manufacturing method according to any one of claims 1 to 3,
A cylindrical body in which fuel is allowed to flow in a cylindrical shape, a through hole is formed in a peripheral wall, and the inner surface side of the through hole is larger in diameter than the outer surface side of the peripheral wall;
A connecting portion that is provided at one end of the cylindrical body and connects the cylindrical body and a high-pressure pipe that sends fuel to the cylindrical body;
A closing portion that is provided at the other end of the cylindrical body and closes the other end;
A housing that is provided on the outer surface of the cylinder, has an interior communicating with the cylinder through the through hole, and a fuel injection member that supplies fuel to the fuel supply target by injection; and
With fuel rail.