KR100407913B1 - Manufacturing methool of high pressure fuel injection pipe's deformation - Google Patents

Abstract

The present invention relates to a method for forming a high pressure fuel injection pipe mainly used as a fuel supply line in ships, automobiles or various engines.

In general, the fuel injection pipe should include a connection head at the end to form a smooth injection path having a constant diameter over the entire length. Looking at the US patent (jan. 16, 1979 NO. 4134430), which is a conventional molding method, After the pipe 1 has been reduced in diameter through a shaft pipe work, it is cold pressed by a crimping mold 4 to form the head 3, followed by reaming, drilling, and polishing. It was made. However, in the conventional method, the problem of high hardness of the end head 3 of the pipe 1 after the cold pressing operation and a high crack rate 3 'formed after the cold pressing operation are high. It was.

The present invention is to solve the above problems, the gist of the pipe 101 is formed in the shape of the head 103 in the center of the injection path 102 in the longitudinal direction in the center without the conventional tube work The lathe work is performed by cutting the lathe to fit the pipe 101 on which the inclined surface 106 is formed. After fixing it to the fixing base 105, the end of the pipe 101 is cold pressed by a pressing die 104 having a protrusion 104 " On the surface, a head 103 is formed in which a crack 103 " Method of forming high pressure fuel injection pipe to obtain finished product by polishing polisher after reamer work or drill work to grind 103 ') to diameter of injection pipe 102 of original pipe 101 with reamer or drill. It is

Description

Manufacturing methool of high pressure fuel injection pipe's deformation

The present invention relates to a method for forming a high pressure fuel injection pipe mainly used as a fuel supply line in ships, automobiles or various engines.

In general, the fuel injection pipe should include a connection head at the end to form a smooth injection path having a constant diameter over the entire length. If the injection molding of the head does not form a smooth injection path with the same diameter, high pressure is required. If the pressure on the wall surface is not constant, such as a recess, it may cause gradual corrosion from the weak hardness and also cause vibration of the fluid, which may cause abnormal operation of the engine. Cracks and breaks may occur from inside the walls to the outside.

Therefore, a method of forming a high-pressure fuel injection pipe forming a smooth injection path having a constant diameter over the entire length including the head to overcome the above problems is known from the US patent (jan. 16, 1979 NO. 4134430). This is as follows.

Figure 1 is a conventional high-pressure fuel injection pipe forming method process drawing, the diameter of the pipe (1) as a raw material through the tube work to reduce the diameter and then cold pressing work by the pressing die (4) followed by reamer work or drill work and polishing It shows the process of making the finished product by polishing.

Referring to FIG. 2 in detail, the pipe 1 which compresses the end of the pipe 1 (see FIG. 2A) having the injection path 2 formed in the longitudinal direction at the center thereof becomes a small injection path 2 ′. ') (See FIG. 2B). After fixing it to the holder (5), the conical or bow-shaped surface by cold pressing the narrow pipe (1 ') with a crimping mold (4) in which the shaped portion (4') of the head (3) is formed. To make a part of the head (3) (see Fig. 2C). After the process is completed, cracks 3 'are formed in the narrow injection path 2' of the head 3, and finely roughened surfaces are formed on the surface thereof (see FIG. 2D). 2) Grinding and polishing polished to the same diameter as the inlet 2 of the original pipe 1 with a reamer or drill to obtain a finished product (see FIG. 2E).

However, in the conventional method, since the hardness of the pipe (1) end head (3) becomes very high after the cold pressing operation, the hardness of the pipe (1) is relatively low and the hardness of the pipe (1) is low at high pressure. There was a crack or breakage. In addition, in the case where the crack 3 'formed after the cold pressing operation is similar to or larger than the diameter of the injection passage 1, the crack 3' remains after the reamer work or even though the crack 3 'is formed. Even if (3 ') disappears, there is a problem in the defective rate which cannot be used because the hardness is greatly different.

The present invention is to solve the above problems, without the shaft tube work as in the prior art to form the inclined surface at the end of the pipe from the beginning to maintain the hardness of the head portion similar to the pipe portion after cold pressing work cracking The size of the crack is also small.

1 is a process chart of a conventional high pressure fuel injection pipe forming method

Figure 2 is a diagram illustrating a conventional high pressure fuel injection pipe forming method

"2A" is the pipe before processing

"2B" is the state after pipe work

"2C" is cold pressing

"2D" is the state after cold pressing

"2E" is the finished product

3 is a flow chart of a method for forming a high pressure fuel injection pipe of the present invention.

4 is an explanatory diagram of a method for forming a high pressure fuel injection pipe according to the present invention;

"4A" is the pipe before processing

"4B" is the state after lathe

"4C" is cold pressing

"4D" is the state after cold pressing

"4E" is the finished product

Figure 5 is a tissue photograph taken the head portion of the pipe after the cold pressing operation by the method of the present invention

6 is a value measured by the Vickers hardness tester of the head portion of the pipe after cold pressing operation by the method of the present invention

* Explanation of symbols for important parts of the drawings

3-head with 1, 1'-pipe 2, 2'-injection

3'-crack 4-compression mold 4'-form

5-fixture

101-pipe 102, 102'-injection 103-head

103'-crack 103 "-crack 104- crimp mold

104'-molding 104 "-projection 105-fixture

106-slope

This will be described in detail with reference to the accompanying drawings.

3 is a process chart of the method for forming a high-pressure fuel injection pipe according to the present invention by the pressing die 104 after turning the end of the pipe 101, which is a raw material, to form an inclined surface 106 suitable for the shape of the head 103. It shows the process of making the finished product by cold pressing, followed by reaming or drilling and polishing.

4, the end of the pipe 101 (see FIG. 4A) having the injection passage 102 formed in the longitudinal direction at the center thereof may be cut into a lathe to fit the shape of the head 103 to be inclined surface 106. This formed pipe 101 is obtained (see Fig. 4B). After fixing it to the fixing base 105, the end of the lathed pipe 101 is formed by a pressing die 104 in which a protrusion 104 ″ is formed in a circular shape in the shape of the head 103. Is cold pressed to form a head 103 having a conical or bow-shaped surface and in which no crack 103 " is formed on the surface thereof (see Fig. 4C). After the above process, a small crack 103 'is formed in the narrow injection path 102' of the head 103, and finely roughened surfaces are formed on the surface thereof (Fig. 2D). Grinding and polishing the same diameter as the injection path 102 of the original pipe 101 with a reamer or a drill to obtain a finished product (see Fig. 4e).

In the above-described invention, since the lathe work for forming the end of the pipe 101 into the inclined surface 106 is performed without the conventional shaft pipe work in the forming of the high-pressure fuel injection pipe, the cold pressing work is performed with the pressing die 104. When the deformation of the pipe 101 is small, the hardness of the head 103 portion is prevented from becoming very high. In other words, since the end of the pipe 101 is machined into a lathe according to the shape of the head 103 from the beginning, the cold pressing process with the pressing mold 104 is much simpler, but it saves time and money, and the conventional two-stage crimping. The hardness of the head 103 is slightly different from that of the pipe 101 because only one step of pressing (cold pressing operation) is performed without excessive deformation of the pipe 101 without performing (axial pipe work and cold pressing work). It became. Figure 5 is a photograph of the structure of the head 103 of the pipe 101 after the cold pressing operation by the method of the present invention, the only difference in the structure of the crack groove (103 ') portion is found to show a slight difference in the rest 6 is measured by a Vickers hardness tester. The crack 103 'is a portion which is lost when grinding with a reamer or a drill. In the finished product, the hardness of the injection paths 102 and 102' becomes constant, and above all, the crack ( Since the size of 103 ') is small, there is almost no defect rate, which is a very effective invention in the work yield.

In addition, by forming a pressing mold 104 to form a protrusion 104 ″ in a circular shape on the shaped portion 104 ′ of the head 103, the cold pressing operation is better and the appearance is good.

Claims (1)

Turning the end of the pipe 101, the injection path 102 is formed in the center in the longitudinal direction to the shape of the head 103 to the lathe to obtain a pipe 101 formed with an inclined surface 106 After fixing it to the holder 105, the end of the pipe 101, which is lathed with a pressing die 104, in which a protrusion 104 " is formed in a circular shape in the shape of the head 103, 104 '. After cold pressing, cold pressing is performed to form a head 103 having a conical or bow-shaped surface, and the crack 103 is not formed in a circular shape on the surface thereof. After reaming or drilling a narrow injection path 102 'and a crack groove 103' formed therein with a reamer or a drill to have the same diameter as the injection path 102 of the original pipe 101. High pressure fuel injection pipe forming room with polished polishing to get the finished product .