JPH05200429A - Manufacture of high pressure fuel injection tube material - Google Patents

Abstract

PURPOSE:To provide the method for manufacturing the high pressure fuel injection tube wherein an inclined surface whose diameter is contracted in the injection direction of high pressure fuel is formed on the inner peripheral surface. CONSTITUTION:A core metal 2 forming an inclined surface T on its outer peripheral surface is inserted into a cylindrical origin tube 1, the origin tube 1 with an inserted core metal 2 is passed through a drawing hole 3' of a drawing member 3 provided with the drawing hole 3' having the inner diameter smaller than the outside diameter of the origin tube 1, a inclined surface T is formed on the inner peripheral surface of an intermediate worked tube 1', thereafter, the core metal 2 is extracted from the intermediate worked tube 1'. In this way, the high-pressure fuel injection tube material having, on the inner peripheral surface, an inclined surface whose diameter is contracted in the injection direction of high-pressure fuel can be manufactured with high quality by a simple stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high pressure fuel injection pipe material, and more particularly to a method for manufacturing a high pressure fuel injection pipe material used in a diesel internal combustion engine.

[0002]

2. Description of the Related Art In a diesel internal combustion engine, there is a strong tendency to increase the pressure of fuel in order to reduce NOx and prevent black smoke. Recently, the injection time is 1 to 2 msec and the maximum flow velocity is 50 m / se.
c, internal pressure 600 to 1000 Kgf / cm ² (peak value)
It is required to inject high-pressure fuel. For this reason, high-pressure fuel injection pipes used in diesel internal combustion engines require (1) durability against repeated high-pressure fatigue, (2) cavitation erosion resistance (3) durability against vibration from the engine and vehicle body. There is. In response to this request, a high-pressure fuel injection pipe of this kind has a diameter of 25 to
Using a thick thin steel tube having a wall thickness of 40%, the inner peripheral surface of which is subjected to a special internal cutting treatment for drawing and annealing (Japanese Patent Publication No. 51-21391), or a thick steel pipe. The inner tube made of stainless steel with a flow passage formed inside is press-fitted to the outer tube made of to form a double metal tube, and the wall thickness of the stainless steel inner tube is set to the outer diameter of the entire double metal tube. It is set to 1.5 to 8.5% (Japanese Patent Publication No. 1-46712).

On the other hand, in this type of high-pressure fuel injection pipe, if a reduction pipe whose cross-sectional area is reduced along the axial core is used, it is effective for high pressure generation due to the dynamic action of fluid in the pipe. , Especially when using a fuel injection pump with a high oil transfer rate,
It has been confirmed that the effect of high pressure generation is enhanced (Proceedings of the 67th Ordinary General Meeting of the Japan Society of Mechanical Engineers Vol.
B).

[0004]

Conventionally, as described above,
(1) Durability against repeated high-pressure fatigue (2) Cavitation erosion resistance (3) Satisfies durability against vibration from the engine and vehicle body, and the inner peripheral surface is reduced in diameter in the downstream direction of injection of the high-pressure fuel As a method of manufacturing a high-pressure fuel injection pipe material with a taper formed, a cylindrical pipe material is cut into a large number of blocks at right angles to the axis, and the inner peripheral surface of each block is cut to form a part of the injection taper. It is slightly suggested that these blocks are sequentially fixed to each other by holding clamps so that the injection taper is concentric with each other to obtain a high-pressure fuel injection pipe material having a continuous injection taper formed in steps on the inner peripheral surface. It's just that. However, the proposed method requires complicated cutting work and requires a holding and tightening tool, which increases the number of parts and complicates the structure.

The present invention has been made in view of the present situation of the high-pressure fuel injection pipe of this kind as described above, and its purpose is to reduce the diameter of at least a part of the inner peripheral surface in the injection direction of the high-pressure fuel. An object of the present invention is to provide a method for manufacturing a high-pressure fuel injection pipe material having an inclined surface.

[0006]

The above-mentioned object is to provide a high-pressure fuel injection pipe for supplying high-pressure fuel in which at least a part of the inner peripheral surface is formed with an inclined surface whose diameter is reduced in the injection direction (nozzle direction) of the high-pressure fuel. In the method for producing a high-pressure fuel injection pipe material to be produced, an inserting step of inserting a core metal having an inclined surface formed on an outer peripheral surface in the raw pipe, and the raw pipe in which the core metal is inserted are provided outside the raw pipe. A drawing step of passing the drawing hole of a drawing member having a drawing hole having an inner diameter smaller than the diameter once to form an intermediate processing tube and forming the inclined surface on the inner peripheral surface of the intermediate processing tube; It is achieved by providing a withdrawing step of withdrawing the cored bar from the intermediate processed pipe that has passed through, and performing each of the steps at least once.

[0007]

According to the present invention, the core metal having the straight or curved inclined surface tapering from the rear end side to the front end side is inserted into the original pipe and passed through the drawing hole of the drawing member to perform the pulling process. ,
A cylindrical inner peripheral surface with a single inner diameter is successively and closely adhered to the outer peripheral surface of a cored bar having an inclined surface to form a conical continuous inclined surface, and then the cored metal is removed to form an inner peripheral surface. It is possible to easily obtain a high-pressure fuel injection pipe material having an inclined surface.

Further, by repeating the steps of inserting the core metal, pulling the core metal, and extracting the core metal several times in order, the difference between the minimum inner diameter and the maximum inner diameter of the inner peripheral surface can be increased, or the inner diameter of the inner pipe can be adjusted in advance. It is also possible to insert a stainless pipe having excellent corrosion resistance as a pipe and perform the above steps to form a double pipe.

[0009]

Embodiments of the present invention will be described below with reference to FIGS.

1 to 3 are explanatory views of a first embodiment of the present invention. In this embodiment, the outer diameter D1 is φ in the inserting step.
Cylindrical J with 9.3 m / m and inner diameter d1 of φ3.7 m / m
ISG 3455 STS370 raw pipe 1 has a piano wire core in which an outer peripheral surface is formed with an inclined surface T having a tip diameter of φ1.5 m / m, a rear end diameter of φ2.0 m / m and a length of 500 m / m. Gold 2 is inserted at the tip side of 255 m / m. Then, in the drawing step, the raw pipe 1 into which the core metal 2 is inserted is drawn by a pulling member 3 having a pulling hole 3'having a smaller diameter than the outer diameter D1 of the raw pipe 1 and an inner diameter D2 of φ6.4 m / m. As shown in FIG. 1, drawing is performed in the arrow direction. By the drawing process in this drawing process, an intermediate processed pipe 1'having an inclined surface T of 500 m / m in length formed on the inner peripheral surface as shown in FIG. 2 is manufactured. The core metal 2 is pulled out from the intermediate working pipe 1'by an extracting step, and the intermediate working pipe 1'is cut at a position A-A corresponding to the insertion end of the core metal 2 as shown in FIG. The diameter is φ6.4 m / m, the minimum inner diameter on the injection direction (nozzle direction) side is φ1.6 m / m, the maximum inner diameter on the pump side (upstream side of high-pressure fuel injection) is φ2.0 m / m, and the inclined surface T is provided. ,
High-pressure fuel injection pipe material 5 with a substantially cylindrical shape and a length of about 500 m / m
Is formed, and a high-pressure fuel injection pipe having an inner peripheral surface as an inclined surface is produced from the high-pressure fuel injection pipe material 5 through predetermined terminal processing.

In the first embodiment, since the inner peripheral surface of the raw pipe 1 is pressed against the outer peripheral surface of the cored bar 2 in the drawing step, the high pressure fuel injection pipe material 5 has a continuous inclined surface T and is homogeneous and dense. A high quality inner peripheral surface is formed.

In the first embodiment, the minimum inner diameter D3 of the high-pressure fuel injection pipe member 5 is 1.6 m / m and the maximum inner diameter d2 is φ.
At 2.0 m / m, d2 = D3 + 0.4 m / m and a minimum inner diameter D3 up to about 30% can be produced. When the maximum inner diameter d2 is larger than the minimum inner diameter D3, the thickness of the raw material 1 is excessively crushed by the core metal 2 on the maximum inner diameter side, which may cause breakage in the drawing process.

In the first embodiment, as shown in FIGS. 1 to 3, not only the target inclined surface T is obtained by passing through the drawing hole once, but the inner diameter of the drawing hole is the outer diameter of the target injection pipe material. Using a plurality of drawing members that gradually come close to each other, and at the same time, use a plurality of metal cores with an inclination formed so that the metal core also gradually comes close to the target inclined surface T, and by sequentially combining these, performing multiple drawing processes. As a result, it becomes possible to manufacture a high-pressure fuel injection pipe material having higher quality and a larger difference between the minimum inner diameter and the maximum inner diameter of the inner peripheral surface.

In the first embodiment, the cored bar 2 is made of steel, spring steel, piano wire or the like, which is hard and has a relatively high tensile strength in consideration of the subsequent drawing process. The surface is treated by electrolytic polishing or the like, or by using a lathe to form an inclined surface, and then hard chrome plating or tin plating is applied to harden the surface, or the surface is treated to make it compatible or releasable. used. Further, in the drawing step, fluorine resin, molybdenum disulfide, expanded pipe oil, etc. were used as a separating material between the raw pipe 1 and the core metal 2.

FIGS. 4 to 6 are explanatory views of the second embodiment of the present invention. In the second embodiment, as shown in the finished product of FIG. An inclined surface T1 that reduces in diameter in the injection direction (nozzle direction) of the high-pressure fuel is formed at an intermediate position in the direction, and the inner circumference of the raw pipe 1 on the nozzle side and the pump side (upstream side of high-pressure fuel injection) of the raw pipe 1 is formed. This is a case where the surfaces are formed on circumferential surfaces having the same diameter with the axis as the center. In this case, the peripheral surface on the front end side is a small-diameter peripheral surface and the peripheral surface on the rear end side is a large-diameter peripheral surface, and the front end is located at an intermediate position in the axial direction of the peripheral surface sandwiched between these peripheral surfaces. A cored bar 2 having an inclined surface T1 whose diameter is reduced on the side is used. A substantially cylindrical high-pressure fuel injection pipe material 5 as shown in FIG. 6 is formed through the insertion process, the withdrawal process, and the extraction process similar to those of the first embodiment, and the high-pressure fuel injection pipe material 5 is end-processed. As a result, a high-pressure fuel injection pipe having an inclined surface at an intermediate position on the inner peripheral surface is created. Also in the second embodiment, the large-diameter intermediate processing pipe processed in the first embodiment is subjected to the drawing process by using the core metal having the inclination in the intermediate portion in the axial direction, so that the inner circumference is further improved in quality. It is possible to manufacture high pressure fuel injection tubing where the difference between the minimum and maximum inner diameters of the faces is greater. Other manufacturing conditions and effects of the second embodiment are the same as those of the first embodiment already described.

7 to 9 are explanatory views of the third embodiment. In the third embodiment, as shown in the finished product of FIG. 9, the high pressure fuel injection pipe member 5 is provided on the inner peripheral surface on the pump side. , In the case of forming the inclined surface T2 having a reduced diameter in the injection direction of the high-pressure fuel (the nozzle direction). In the third embodiment, the core metal 2 has a peripheral surface on the tip end side which is a circumferential surface having the same diameter with the shaft center as the center, and an inclined surface T2 which is reduced in diameter toward the tip end on the peripheral surface on the rear end side. To use. Also in this case, the same insertion step, withdrawal step, and
After the extraction step, a substantially cylindrical high-pressure fuel injection pipe material 5 is formed as shown in FIG. 9, and the high-pressure fuel injection pipe material 5 is end-processed to form an inclined surface on the inner peripheral surface that is reduced in diameter toward the pump side. A high pressure fuel injection tube having is created. In the third embodiment as well, the large-diameter intermediate processed pipe processed in the first embodiment is subjected to the drawing process by using the core bar having the inclined surface on the rear end side that is reduced in diameter toward the front end. It is possible to manufacture a high-pressure fuel injection pipe material having a high quality and a large difference between the minimum inner diameter and the maximum inner diameter of the inner peripheral surface. Other manufacturing conditions and effects of the third embodiment are the same as those of the first embodiment already described.

FIGS. 10 and 11 are explanatory views of the fourth embodiment. In the fourth embodiment, as shown in the completed view of FIG. 11, the inner peripheral surface of the intermediate working pipe 1'is directed in the nozzle direction. This is a case where the diameter is reduced to form the inclined surface T3 having a curved cross-sectional shape in the axial direction. In this case, the cored bar 2 is used in which the inclined surface T3 whose diameter is reduced in the front end direction and whose axial cross-sectional shape is curved is formed on the outer peripheral surface. Also in this case, as in the first embodiment, as shown in FIG. 11, after the insertion step, the withdrawal step, and the withdrawal step,
A substantially cylindrical high-pressure fuel injection pipe material 5 is formed, and the high-pressure fuel injection pipe material 5 is end-processed to form a high-pressure fuel injection pipe having a curved axial cross section on its inner peripheral surface. Fourth
Also in the embodiment, the high-pressure fuel injection pipe material having a higher quality and a larger difference between the minimum inner diameter and the maximum inner diameter of the inner peripheral surface is manufactured by performing the drawing process a plurality of times as in the first embodiment. It is possible.

12 and 13 are explanatory views of the fifth embodiment. In this fifth embodiment, a thin hollow inner tube 1a made of SUS304 is previously inserted into a raw material 1 made of STS35,
Next, after inserting the cored bar 2 having the inclined surface T4, a drawing process is performed using the drawing member 3 having the drawing-out hole 3'to form an intermediate processed tube 1 ', and then the cored bar 2 is extracted. By cutting this at the position AA in FIG. 13, a high-pressure fuel injection pipe material having the SUS inner pipe 1a and having the inclined surface T4 on the inner peripheral surface is obtained.

Next, FIGS. 14 and 15 show sixth and seventh embodiments. In the sixth embodiment, a stainless inner pipe 1a is provided inside the raw pipe 1 over substantially the entire length of the raw pipe 1. After inserting and swaging the ends in advance, the core metal 2 is inserted and passed through the extraction hole D2 of the extraction member 3 to perform the extraction process to extract the core metal, and in the seventh embodiment, the stainless steel pipes are preliminarily separated from each other. After forming it on the polymerization tube, insert and pull out the core metal,
A high pressure fuel injection pipe material having an inclined surface on each inner peripheral surface is obtained by performing a core metal extracting step.

The embodiment of FIGS. 12 to 14 is as follows.
In the manufacturing method in which the steps of inserting the cored bar, withdrawing the cored bar, and extracting the cored bar are repeated several times, the inner tube 1a can be inserted into the intermediate processed tube 1'before the final step.

As described above, according to each of the embodiments, a straight or curved slanted surface whose diameter is reduced in the injection direction of the high-pressure fuel is formed by a simple process, and a homogeneous and dense high quality is obtained. It becomes possible to manufacture a high-pressure fuel injection pipe material having an inner peripheral surface of

In the embodiment, on the inner peripheral surface of the high-pressure fuel injection pipe material, an inclined surface whose diameter is reduced to the nozzle side over the entire surface, an inclined surface whose diameter is reduced to the nozzle side at an intermediate position in the axial direction, and a pump side is attached to the nozzle side. The case of manufacturing the high-pressure fuel injection pipe material in which the diameter of the inclined surface is reduced to the nozzle side on the entire surface and the curved inclined surface is formed in the axial cross section has been described. However, the present invention is not limited to the examples,
For example, when the inner peripheral surface of the high-pressure fuel injection pipe material has different inclinations and an inclined surface composed of a plurality of inclined surfaces having a reduced diameter on the nozzle side is formed, the inclined surface whose diameter is reduced on the nozzle side is a nozzle of the high-pressure fuel injection pipe material. It is applied when various inclined surfaces are formed, such as when it is formed only on the side.

[0023]

According to the present invention, a high-pressure fuel injection pipe material having a uniform, dense and high-quality inner peripheral surface on which an inclined surface whose diameter is reduced in the high-pressure fuel injection direction is formed by a simple process is manufactured. It is possible to produce a high-quality high-pressure fuel injection pipe.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a drawing process of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a sampling process of the first embodiment of the present invention.

FIG. 3 is an explanatory view of a high-pressure fuel injection pipe material manufactured according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a drawing process of a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a sampling process of the second embodiment of the present invention.

FIG. 6 is an explanatory view of a high-pressure fuel injection pipe material manufactured according to the second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a drawing process of the third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a sampling process according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram of a high-pressure fuel injection pipe material manufactured according to the third embodiment of the present invention.

FIG. 10 is an explanatory diagram of a drawing process of a fourth embodiment of the present invention.

FIG. 11 is an explanatory diagram of a high-pressure fuel injection pipe material manufactured according to the fourth embodiment of the present invention.

FIG. 12 is an explanatory diagram of a drawing process of the fifth embodiment of the present invention.

FIG. 13 is an explanatory diagram of a high-pressure fuel injection pipe material manufactured according to the fifth embodiment of the present invention.

FIG. 14 is a schematic explanatory diagram of a drawing process of a sixth embodiment of the present invention.

FIG. 15 is a schematic explanatory diagram of a drawing process of a seventh embodiment of the present invention.

[Explanation of symbols]

 1 original pipe 1'intermediate processing pipe 1a inner pipe 2 core metal 3 drawing member 3'drawing hole 5 high-pressure fuel injection pipe material T, T1, T2, T3, T4 inclined surface

Claims (2)

[Claims] 1. A method of manufacturing a high-pressure fuel injection pipe for producing a high-pressure fuel injection pipe, wherein at least a part of an inner peripheral surface of the high-pressure fuel has an inclined surface whose diameter is reduced in the injection direction of the high-pressure fuel. An inserting step of inserting a cored bar having an inclined surface formed on the outer peripheral surface into the tube, and a withdrawal member having an extraction hole having an inner diameter smaller than the outer diameter of the original tube, the original tube having the cored bar inserted thereinto. A drawing step of forming an inclined surface on the inner peripheral surface of the intermediate processed tube by passing through the drawing hole to form an intermediate processed tube;
And a step of extracting the cored bar from the intermediate processed tube that has undergone the drawing step, and each step is performed at least once. 2. An inner tube is inserted into the raw tube to perform the core bar inserting step, the drawing step and the core bar extracting step.
A method for producing the high-pressure fuel injection pipe material described.