JP2023088230A - Manufacturing method of fuel introduction inlet - Google Patents

Abstract

To accurately mold a fuel introduction inlet without forming a parting line, to elongate a life of a metal mold, to eliminate a material loss, and to achieve a low cost.SOLUTION: By cold-forging a columnar molding raw material X from its axial direction by using a cold forging machine 30 having a halved fixed metal mold 31 and a halved variable metal mold 32 composed of a cemented carbide or high-speed metal, a solid molding 10A having a fuel introduction shaft part 13 having a columnar screw coupling end part 11a at a tip part, and an attachment leg part 14 to a delivery pipe 1 protruding from a rear-end lower part of the fuel introduction shaft part 13 while obliquely being inclined or orthogonal to an axial direction of the fuel introduction shaft part 13 is molded, after that, screw-processing is applied to an external periphery of the columnar screw coupling end part 11a in a succeeding process, and a fuel introduction port 12 and a communication hole 15 are formed at the fuel introduction shaft part 13 of the solid molding 10A.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method of manufacturing a fuel inlet attached to a delivery pipe used in an internal combustion engine.

2. Description of the Related Art Conventionally, in an internal combustion engine, a delivery pipe is used to distribute fuel supplied from a fuel supply pipe to a fuel injection valve provided in each cylinder.

Conventionally, this type of delivery pipe is made of a cylindrical body, and a plurality of insertion portions for mounting a fuel injection valve are provided at predetermined intervals in the longitudinal direction of the cylindrical body having a fuel passage. Each insertion portion is provided with an insertion opening communicating with the fuel passage of the delivery pipe, and a rear end of a fuel injection valve (not shown) is inserted into the insertion opening. One end of the delivery pipe is integrally provided with a fuel inlet portion having a threaded end for screwing a joint portion of a high-pressure fuel supply pipe (not shown) connected to a high-pressure fuel pump. there is Further, a plurality of bolt holes for fixing the delivery pipe to the cylinder head of the internal combustion engine are provided in the cylindrical body portion of the delivery pipe.

Japanese Patent Application Laid-Open No. 2007-54884

By the way, in the above-described delivery pipe, in order to obtain an optimum attachment to the threaded end of the fuel inlet of the joint part of the high-pressure fuel supply pipe even when the engine layout of the internal combustion engine is changed, the high-pressure fuel supply In some fuel delivery pipes, the fuel inlet portion, which is to be connected to the pipe, is positively inclined with respect to the longitudinal direction of the delivery pipe, so that the threaded connection end protrudes in an inclined posture.
In this case, the fuel inlet portion has a complicated shape that protrudes from the delivery pipe in an inclined posture with respect to the axial direction thereof, so that it is very complicated to form the fuel inlet portion integrally with the delivery pipe. becomes difficult.

Therefore, at present, apart from the delivery pipe, the fuel introduction inlet (hereinafter referred to as the inlet), which is the connection part of the high-pressure fuel supply pipe, is formed by hot forging, and then, in the post-process, the screw is processed and the communication hole is processed. and the inlet is attached to one end of the delivery pipe.
In that case, the cylindrical forming material X shown in (a) of FIG. 15 is first preheated, and then in the first step of hot forging, half-split forming recesses are formed as shown in (b) of FIG. A half-split stationary mold (not shown) and a half-split movable mold (not shown) having a half-split molding recess are used to perform burr removal forging from the diameter direction of the cylindrical forming material X, and a circle is formed at the tip. A burr 20a having a fuel introduction shaft portion 23 having a columnar screw connection end portion 21a and a mounting leg portion 24 projecting from one end side portion of the fuel introduction shaft portion 23 perpendicularly to the axial direction thereof and attached to the delivery pipe. A solid molded body 20A is molded. At this time, the burr 20a of the solid molded body 20A is formed thickly on the entire circumference on the center line dividing the fuel introduction shaft portion 23 and the mounting leg portion 24 into two symmetrical shapes. Next, in the second step of hot forging, the burr 20a portion is removed from the burred solid compact 20A by punching to form the solid compact 20A having the outer shape of the inlet shown in FIG. 15(c). . After that, the solid molded body 20A is cooled, and in a post-process, the scale is removed by shot blasting, and further, the cylindrical threaded joint end portion 21a is threaded, and the fuel introduction port of the fuel introduction shaft portion 23 is communicated. The inlet is formed into a desired shape by applying processing such as holes.
The inlet is attached by welding, brazing, or the like in such a manner that the fuel introduction shaft portion 23 protrudes obliquely with respect to the axial direction of the delivery pipe.
However, in the case of forming the inlet by hot forging as described above, first, the solid formed body 20A with burrs is formed by burr removal forging in the first step, and then the solid formed body 20A with burrs is formed in the second step. Since the solid molded body 20A is formed by removing the burr 20a portion from the molded body 20A by punching, there is a problem that a large parting line remains in the solid molded body 20A. is likely to cause variations in the dimensions of the solid molded body 20A, and due to the variation in dimensions, the solid molded body 20A may be held in a posture or holding position by a chuck or the like when processing a screw, a fuel inlet, and a communication hole in a post-process. There was a problem that the force was not constant and the repeatability in the post-process processing was low. Moreover, in hot forging, the life of the metal mold is short, and since the burr 20a portion is removed, the material loss of the molding material X is large, which makes the whole process uneconomical.

Therefore, the present invention was invented to solve the above-described drawbacks of the conventional art, and apart from the delivery pipe provided with a plurality of insertion portions for mounting the fuel injection valve, it becomes a connection portion of the high pressure fuel supply pipe. When molding fuel inlets with complex shapes, the parting line is zero or as thin as possible, and while the variation in overall dimensions is kept small while the volume movement is large, it is possible to mass-produce high-precision solid inlet moldings. As a result, the molded body can be firmly held and formed with high repeatability in the post-process machining of screws and communication holes.In addition, the life of the mold can be extended, material loss can be eliminated, and cost can be reduced. An object of the present invention is to provide a method for manufacturing a fuel introduction inlet that can be manufactured.

The invention according to claim 1 of the present application is a method of manufacturing a fuel introduction inlet to be attached to a delivery pipe having a fuel passage and a plurality of insertion portions for attaching a fuel injection valve. Using a cold forging machine equipped with a half fixed mold having a half forming recess made of cemented carbide or high speed steel and a half movable mold having a half forming recess, these halves A cylindrical molding material is cold-forged from its axial direction by a movable mold and a half fixed mold, and a fuel introduction shaft portion having a cylindrical threaded end portion at the tip and a rear end of the fuel introduction shaft portion. A solid compact is formed from the lower part with a mounting leg portion for attachment to the delivery pipe protruding at a right angle or obtuse angle to the axial direction of the fuel introduction shaft, and then the solid compact is cold-rolled. After removing from the forging machine, in a subsequent process, the outer periphery of the cylindrical threaded end of the molded body is threaded to form a threaded end, a fuel inlet is formed in the center of the threaded end, and the fuel is introduced. It is characterized in that a communication hole is formed which communicates with the port and is open to the rear end side surface of the fuel introduction shaft portion to communicate the fuel introduction port with the fuel passage.

The invention according to claim 2 of the present application is the method for manufacturing a fuel introduction inlet according to claim 1 of the present application, wherein the cylindrical threaded connection end is connected to the tip of the fuel introduction shaft through a stepped portion. On the other hand, the shaft diameter of the cylindrical forming material is the same or smaller than the shaft diameter of the cylindrical screw connection end, and the forming material is cold forged from the axial direction so that the load can be applied. When applied, the volume of the molding material is transferred to the fuel introduction shaft molding part and the mounting leg molding part in both molds at once by using the gap space due to the shaft diameter difference between the molding material and the fuel introduction shaft part. 3. The fuel introducing shaft and the mounting leg protruding from the rear end lower portion of the fuel introducing shaft are formed simultaneously.

According to the method of manufacturing a fuel inlet according to the present invention, the inlet formed separately from the delivery pipe is formed into a columnar shape by a cold forging machine whose mold is made of cemented carbide or high-speed steel. Since the material is cold-forged from its axial direction, the parting line of the cold-forged solid compact can be made zero or as thin as possible, and the variation in overall dimensions is small, resulting in high precision. Actual compacts can be mass-produced. As a result, it can be stably and accurately held in a chuck for processing in a post-process, and the repeatability can be remarkably improved during processing of screws and communication holes to maintain processing quality. In addition, in cold forging, it is possible to extend the life of the mold and at the same time suppress the material loss of the molding material, so that the cost can be reduced as a whole.

In addition, while the cylindrical screw connection end portion is set at the tip of the fuel introduction shaft portion with a diameter smaller than that of the fuel introduction shaft portion via a stepped portion, the cylindrical screw connection end portion of the fuel introduction shaft portion is used as a cylindrical molding material. By using a material having the same diameter as or smaller than the shaft diameter of the fuel introduction shaft, that is, a material having a smaller diameter than the shaft diameter of the fuel introduction shaft, the material to be formed is cold forged from the axial direction and a load is applied to the material to be formed. When the pressure is applied, a large volume of the molding material is transferred to the fuel introduction shaft molding part and the mounting leg molding part in both molds by using the gap space due to the shaft diameter difference between the molding material and the fuel introduction shaft part. By doing this all at once, the fuel introduction shaft and the mounting leg protruding from the rear end lower portion of the fuel introduction shaft can be simultaneously formed at once. As a result, the solid molded body having the fuel introduction shaft portion having the cylindrical threaded end portion and the mounting leg portion projecting from the rear end lower portion of the fuel introduction shaft portion can be manufactured with less variation in overall dimensions and higher height. Accurate solid molding can be molded.

1 is a partially omitted perspective view of a delivery pipe to which an inlet manufactured by a manufacturing method according to the present invention is attached; FIG. FIG. 4 is a side view of an inlet manufactured by the manufacturing method according to the present invention; It is a front view of the same inlet. It is a front view center longitudinal cross-sectional view of the same inlet. It is an explanatory view showing a cold forged state of the same inlet. 1 is a front view of a cylindrical molding material; FIG. 1 is a side view of a cold forged solid compact; FIG. FIG. 11 is a side view of an inlet with a different shape for the mounting legs; It is a front view of the same inlet. It is a front view center longitudinal cross-sectional view of the same inlet. It is an explanatory view showing a cold forged state of the same inlet. It is a side view of the same cold forged solid compact. It is explanatory drawing which shows another closed cold forging state. It is explanatory drawing which shows another closed cold forging state. It is a conventional explanatory view.

An embodiment of a method for manufacturing a fuel introduction inlet according to the present invention will be described below with reference to the drawings.

First, FIG. 1 shows a delivery pipe 1 for an internal combustion engine fitted with an inlet 10 manufactured by the manufacturing method of the present invention.
The delivery pipe 1 is a cylindrical casting, and has an insertion portion 2 for mounting a fuel injection valve (not shown) in the longitudinal direction of a cylindrical body portion 1a having a fuel passage (not shown). 2 are provided at predetermined intervals, and each of the insertion portions 2 . . . 2 is provided with an insertion port 2a . . . , the rear end of the fuel injection valve is inserted into 2a. A plurality of bolt holes 3 . . . 3 for fixing the delivery pipe 1 to the cylinder head of the internal combustion engine are provided in the cylindrical body portion 1a of the delivery pipe 1. As shown in FIG.
One end of the delivery pipe 1 is a portion to which a tip portion 5 of a high-pressure fuel supply pipe 4 connected to a high-pressure fuel pump (not shown) is screwed. A fuel introduction inlet 10 is separately provided by welding, brazing, or the like, protruding from 1 in a posture inclined with respect to the axial direction.

As shown in FIGS. 2 to 4, the inlet 10 is made of a forged body formed by a cold forging machine whose mold is made of cemented carbide or high speed steel (high speed steel), separately from the delivery pipe 1 .
Specifically, as shown in FIGS. 2 to 4, a cylindrical fuel introduction shaft has a threaded end 11 at its tip, which serves as a connecting portion for the high-pressure fuel supply pipe 4, and a fuel introduction port 12 at its center. 13, and a mounting leg 14 (protruding downward in FIGS. ) on the rear end side of the fuel introduction shaft portion 13, and when the fuel introduction shaft portion 13 is attached to the delivery pipe 1 via the mounting leg portion 14, the fuel introduction port 12 is aligned with the fuel passage of the delivery pipe 1. A communication hole 15 for communication is formed.

As shown in FIG. 1, the inlet 10 is attached to one end of the delivery pipe 1 in an inclined position with respect to its longitudinal direction by welding or brazing. By attaching the inlet 10 to one end of the delivery pipe 1 in an inclined position with respect to the delivery pipe 1 in this way, it is possible to widely adapt to changes in the layout of the internal combustion engine, etc., and to maintain high pressure in an optimum state. The tip portion 5 of the fuel supply pipe 4 can be attached to the threaded end 11 of the fuel introduction shaft portion 13 .
Further, when the inlet 10 is attached to one end of the delivery pipe 1 by, for example, welding in a posture inclined with respect to the delivery pipe 1, the fuel inlet 12 of the inlet 10 is connected to the fuel of the delivery pipe 1 through the communication hole 15. It will be communicated and connected to the passage without leakage.

As a result, the fuel supplied from the high-pressure fuel supply pipe 4 passes through the fuel passage of the cylindrical body portion 1a of the delivery pipe 1 from the fuel introduction port 12 of the inlet 10 through the communication hole 13, and flows through the insertion portions 2...2. is distributed to each fuel injection valve through the insertion openings 2a . . . 2a of the engine and supplied into the fuel chamber of the engine.

Next, a method of manufacturing the fuel introduction inlet 10 formed and used as described above will be described.
As a method of manufacturing the inlet 10, first, as shown in FIG. Using a cold forging machine 30 equipped with a half-movable mold (punch) 32 having a forming recess 32a, the half-fixed mold 31 and the half-movable mold 32 are used to form a mold as shown in FIG. A cylindrical molding material X is cold forged from its axial direction, and a fuel introduction shaft portion 13 having a cylindrical threaded end portion 11a at the tip shown in FIG. A solid molded body 10A is molded from a solid molded body 10A having mounting legs 14 projecting perpendicularly to the axial direction of the delivery pipe 1. As shown in FIG.
Here, in FIG. 5, the dotted line on the solid molded body 10A indicates the abutting surfaces of the lower fixed half mold 31 and the upper movable half mold 32 when molding the solid molded body 10A. This abutting surface is formed on an extension of a horizontal line that divides the thickness of the mounting leg portion 14 in FIG. The molding recess 32a formed in the bottom surface of the half-split movable mold 32 forms a molding space for the upper half of the solid molded body 10A. are doing. Then, with the molding material X interposed between the lower half fixed mold 31 and the upper half movable mold 32, the upper half movable mold 32 is moved to the lower half fixed metal mold. It is moved to the die 31 side, and the molding material X is cold-forged by the forming force and closing force of the half-split fixed mold 31 and the half-split movable mold 32, and the mounting leg portion 14 is laterally protruded into the desired shape. A real molded body 10A is molded.

After that, the solid molded body 10A molded as shown in FIG. 7 is taken out from the cold forging machine 30, and in a post-process, the outer peripheral portion of the cylindrical threaded connection end portion 11a is appropriately threaded by a threading machine (not shown). Cutting is performed to form a threaded end 11 as shown in FIG. 2, and a fuel inlet 12 is formed by appropriately drilling a hole in the center of the threaded end 11 using a drilling machine (not shown), Further, a communication hole 15 is formed which communicates with the fuel introduction port 12 and opens at the rear end side surface of the fuel introduction shaft portion 13 to communicate the fuel guide 12 with the fuel passage of the delivery pipe 1. of the fuel introduction inlet 10 is formed.

As described above, according to the method of manufacturing a fuel introduction inlet of the present invention, the inlet 10 formed separately from the delivery pipe is formed into a columnar shape by a cold forging machine whose mold is made of cemented carbide or high-speed steel. Since the material X is formed by cold forging from its axial direction, the parting line of the cold forged solid formed body 10A can be made zero or as thin as possible, and the variation in the overall dimensions is small and high. It is possible to mass-produce the solid molded bodies 10A with high accuracy. As a result, it can be stably and accurately held in a chuck for processing in a post-process, and the repeatability can be remarkably improved during processing of screws and communication holes to maintain processing quality. In addition, in cold forging, it is possible to extend the life of the mold and at the same time suppress the material loss of the molding material, so that the cost can be reduced as a whole.
Even if the parting line of the solid molded body is slightly thin, it can be easily removed by barrel treatment or the like, and can be stably held in the cutting chuck in the next process, thereby maintaining processing quality.

Further, in the above-described embodiment, the cylindrical threaded end portion 11a is set at the tip of the fuel introducing shaft portion 13 via a stepped portion to have a diameter smaller than that of the fuel introducing shaft portion 13. The shaft diameter is the same as or smaller than the shaft diameter of the cylindrical threaded end portion 11a of the introduction shaft portion 13, that is, the shaft diameter is set to be smaller than the shaft diameter of the fuel introduction shaft portion 13 is used. In the case of setting in this manner, when the forming material is subjected to cold forging from its axial direction and a load is applied to the forming material, the gap space due to the shaft diameter difference between the forming material and the fuel introduction shaft portion 13 is utilized. At once, a large volume of the molding material is transferred to the fuel introduction shaft portion molding portion and the mounting leg portion molding portion in both molds, and the fuel introduction shaft portion 13 and the rear end lower portion of the fuel introduction shaft portion 13 protrude. The mounting leg portion 14 can be formed at once at the same time. As a result, the solid body 10A, which includes the fuel introduction shaft portion 13 having the cylindrical threaded end portion 11a and the mounting leg portion 14 protruding from the lower rear end portion of the fuel introduction shaft portion 13, can be manufactured without variation in overall dimensions. It is possible to mold a solid molded body 10A that is smaller and has higher precision.

Further, in the above-described embodiment, the inlet 10 provided with the mounting leg portion 14 projecting (horizontally protruding) to the delivery pipe 1 perpendicularly to the axial direction of the fuel introduction shaft portion 13 has been described. , to the delivery pipe 1 projecting obliquely at an obtuse angle with respect to the axial direction of the fuel introduction shaft portion 13 from the longitudinal middle portion of the fuel introduction shaft portion 13 as shown in FIGS. The inlet 10 having the mounting leg portion 14 (protruding downward in FIGS. 8 to 10) is also manufactured by the manufacturing method of the present invention by the cold forging machine 30 shown in FIG. and similar effects can be obtained.

In this case, the portion indicated by the dotted line in FIG. 11 of the solid molded body 10B indicates the abutting surfaces of the lower fixed half mold 31 and the upper movable half mold 32. As shown in FIG. In other words, this abutting surface is formed by a slanted line that divides the thickness of the obliquely protruding mounting leg 14 into two in the thickness direction, and an orthogonal line of the fuel introduction shaft 13 that connects to the base end of the slanted line. will be formed on the line connecting The molding hole 31a of the fixed mold half 31 and the knockout pin 33 form a molding space for the lower half of the solid molded body 10B. 32a forms a molding space for the upper half of the solid molded body 10A.

In the solid body 10B shown in FIG. 12, both sides of the fuel introduction shaft portion 13 are flattened 13a, 13a to form an oval shape. It is possible to perform secondary processing such as screw processing and cutting with high precision after the substrate is securely and firmly fixed by the chuck on the table side.

In addition, the cold forging in the present invention is not limited to the cold forging of the configuration of the above-described embodiment, but is a concept including closed cold forging. Therefore, as another embodiment, for example, as shown in FIGS. 13 and 14, in each half movable mold 31 in the cold forging machine 30 of the above two embodiments, on the side of the half recess 31a It has a closed cold forging structure with a built-in movable forming pin 34 that moves forward and backward. Further, closed cold forging is performed by applying a forming force by advancing (downwardly moving) the movable forming pin 34 toward the half recess 32a, thereby forming the solid formed body 10A or the solid formed body 10B. may

Further, in the above-described embodiments, the description has been given of the one-stage cold forging process for forming the above-described solid molded body 10A or 10B, but it is not limited to the above-described embodiments. Instead, for example, a plurality of stages of cold forging processes, such as preforming the cylindrical forming material X at one end in a previous process, are performed, and the solid molded body 10A or the solid molded body 10B is cold forged step by step. You may do so.

Reference Signs List 1 delivery pipe 1a cylindrical body 2 insertion portion 2a insertion port 10 fuel introduction inlet 10A solid molded body 10B solid molded body 11 threaded end 11a cylindrical threaded end 12 fuel inlet 13 fuel introduction shaft 14 Mounting leg 15 Communication hole X Forming material

Claims (2)

A method of manufacturing a fuel introduction inlet in a delivery pipe having a fuel passage and having a plurality of insertion parts for mounting a fuel injection valve, firstly, a mold made of cemented carbide or high speed steel is divided into halves. Using a cold forging machine equipped with a half fixed mold having a molding recess and a half movable mold having a half molding recess, these half movable molds and half fixed molds A cylindrical molding material is cold forged from its axial direction, and a fuel introduction shaft portion having a cylindrical threaded end portion at the tip, and a fuel introduction shaft portion from the lower rear end of the fuel introduction shaft portion to the axial direction of the fuel introduction shaft portion to form a solid molded body provided with a mounting leg for a delivery pipe projecting at a right angle or obtuse angle, then remove the solid molded body from the cold forging machine, and in a post process, the molded body The outer periphery of the cylindrical threaded end of the is threaded to form a threaded end, and a fuel inlet is formed in the center of the threaded end, and communicates with the fuel inlet and behind the fuel inlet shaft. 1. A method of manufacturing a fuel inlet, characterized by forming a communication hole which is open on an end side surface and communicates a fuel introduction port with a fuel passage. The cylindrical threaded end portion is set at the tip of the fuel introduction shaft portion via a stepped portion to have a diameter smaller than that of the fuel introduction shaft portion, and the shaft diameter of the cylindrical molding material is set to the shaft diameter of the cylindrical threaded end portion. When the material is cold forged from its axial direction and a load is applied, the space created by the difference in axial diameter between the material and the fuel introduction shaft is utilized to The volume of the fuel introduction shaft molding part and the mounting leg molding part in the mold is transferred at once, and the fuel introduction shaft part and the mounting leg projecting from the rear end lower part of the fuel introduction shaft part are molded at the same time. 2. A method of manufacturing a fuel introduction inlet according to claim 1, wherein the method is as follows.

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