JPH0544593A - Manufacture of fuel distributing pipe made of synthetic resin - Google Patents

Abstract

PURPOSE:To completely suppress production of burrs by preventing provision of gaps among the mating surfaces of a moving core and a stationary mold, and a moving mold in a way that the tip part of the moving core is pressed in a state to nip it between the stationary mold and the moving mold. CONSTITUTION:During completion of mating of molds with each other, an outer periphery 12A of the tip part of a first moving core 12 for forming a combustion chamber F is reliably and securely fitted in a tip fitting hole 13A of a second moving core 13. Even when high pressure molten resin is injected in a cavity, the first moving core 12 is prevented from making contact with the stationary mold 10 and the moving mold 11, and no gap is formed among the mating surfaces of the stationary mold 10, the moving mold 11, and the moving core. During molding, production of burrs on the part, opened to a combustion chamber, of, for example, a fuel injection valve mounting hole is completely suppressed.

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 fuel distribution pipe used in a fuel injection device for an internal combustion engine. In the fuel distribution pipe, pressurized fuel discharged from the fuel pump is supplied to the fuel chamber through the fuel inflow passage, and this fuel is distributed to the fuel injection valve arranged in the intake pipe through the plurality of fuel injection valve mounting holes. It is supplied and communicated to the pressure regulator via the fuel discharge passage.

[0002]

2. Description of the Related Art A conventional fuel distribution pipe is, for example, an actual Kaihei 2-5.
No. 0171 and the like. According to this, a fuel inflow path communicating with the fuel pump opens in the fuel chamber at one end of the fuel distribution pipe, and the fuel distribution pipe has a plurality of fuel injection valve mounting holes from one end to the other end along the longitudinal axis. Open in the fuel chamber at intervals, and a fuel injection valve connected to the intake manifold is attached to the fuel injection valve mounting hole.

On the other hand, inside the fuel chamber of the fuel distribution pipe, a pipe-shaped fuel discharge passage is arranged along the longitudinal axis of the fuel distribution pipe, and one end of the fuel discharge passage on the inflow side is located at the other end of the fuel distribution pipe. An opening is made in the fuel chamber, the other end on the outflow side of the fuel discharge passage is opened to the outside from the fuel chamber near one end of the fuel distribution pipe, and this opening is connected to the pressure regulator.

And, the fuel distribution pipe has a reduced weight,
In order to reduce the manufacturing cost, a return pipe receiver, which is injection-molded from a synthetic resin material and supports an end portion of the return pipe forming the fuel discharge passage, is formed so as to project into the fuel chamber of the fuel distribution pipe.

[0005]

Considering the conventional method for manufacturing a fuel distribution pipe, the outer portion of the distribution pipe main body of the fuel distribution pipe is a fixed mold and a movable mold movable opposite to this. Formed by and.

The fuel chamber has a first movable core which is arranged to move forward and backward between the mold mating surfaces of a fixed mold and a movable mold from one side, and a first movable core which is also movable forward and backward from the other side. It is formed by a second movable core arranged so as to face the child.

That is, the front end portions of the first movable core and the second movable core which face each other abut on each other in the fuel chamber formed by these movable cores. This is because when the return pipe receiver projects into the fuel chamber, an undercut portion is formed when casting is formed on one side only by the movable core on one side, and molding is impossible. The opposing end surfaces of the first movable core and the second movable core are in contact with each other at the pipe receiving portion.

On the other hand, the distribution pipe body of the fuel distribution pipe is provided with a plurality of fuel injection valve mounting holes which open into the fuel chamber along the longitudinal axis of the distribution pipe body. Since it is necessary to prepare a fuel injection valve for each
The number of fuel injection valve mounting holes is three, four, five, and six depending on the engine.

By providing a plurality of fuel injection valve mounting holes in the fuel distribution pipe as described above, the length of the longitudinal axis of the fuel chamber formed by the movable core tends to be long. For example, the length of the fuel distribution pipe used for a 6-cylinder engine reaches 300 millimeters.

Here, considering the resin molding of the fuel distribution pipe, the fixed mold, the movable mold, and, for example, the fixed mold and the movable mold are brought into contact with each other in order to form the fuel injection valve mounting hole by casting. Molten resin having a high pressure of 700 Kg / Cm @ 2 is injected into the cavity formed in the mold by the movable core.

According to this, as described above, the movable core for forming the fuel chamber of the fuel distribution pipe having a long overall length swings to the side orthogonal to the longitudinal axis line due to the injection pressure of the molten resin. The runout of the movable core may cause a gap between the fixed mold and the mating surface of the movable mold and the movable core. This gap causes the opening of the fuel injection valve mounting hole to the fuel chamber. Thin burr is generated on the part. Especially in the resin molding, the fluidity of the molten resin is good, so that it is remarkable.

The burr thus generated must be removed after molding, and at the same time, the removed burr must be completely discharged from the product. These man-hours increase the cost of the product and are not preferable. ..

Further, it is considered to increase the mechanical strength of the movable core itself, but this is not preferable because it increases the material cost and the processing cost of the core.

The present invention has been made in view of the above problems, and provides a manufacturing method in which burr is not particularly generated in a fuel injection valve mounting hole during injection molding of a fuel distribution pipe using a synthetic resin material. There is.

[0015]

According to the present invention, in order to achieve the above object, a distribution pipe main body having a fuel chamber formed inside along a longitudinal axis XX thereof, and one end thereof having a fuel chamber. And a fuel inflow path for supplying pressurized fuel discharged from the fuel pump into the fuel chamber, a fuel discharge path for connecting the pressure regulator and the fuel chamber at one end, and one end for the fuel chamber. And a plurality of fuel injection valve mounting holes connected to the fuel injection valve and formed in a synthetic resin material, the fixed mold and the movable mold are arranged so as to be opposed to the fixed mold. At least an outer portion of the distribution pipe main body is formed by the movable mold, and at least a fuel chamber is formed by a first movable core that is arranged between the fixed mold and the movable mold so as to move back and forth. Fixed the outer circumference of the tip of the first movable core It is obtained by pressing clamped by the mold and the movable mold.

[0016]

The tip of the movable core is pressed and sandwiched by the fixed mold and the movable mold, so that both ends of the movable core are fixed by the mold, which causes a high pressure in the cavities. The molten resin is injected, and the swing of the movable core is also suppressed by the injection pressure, so there is no gap between the mating surface of the movable core and the fixed mold, and the movable mold, and burr is generated. Was completely suppressed.

[0017]

EXAMPLE An example of a method of manufacturing a synthetic resin fuel distribution pipe according to the present invention will be described below. 1 is a vertical cross-sectional view showing an assembled state as a fuel distribution pipe, FIG. 2 is a vertical cross-sectional view taken along the line P-P of FIG. 1, FIG. 3 is a vertical cross-sectional view of the distribution pipe main body in FIG. 1, and FIG. FIG. 5 is a vertical cross-sectional view taken along the line RR in FIG. 4, in which a mold assembly for molding the pipe body is formed.
FIG. 6 is a vertical sectional view showing another embodiment. In addition, in the description, the upper, lower, left, and right are referred to in the drawings, and the present invention is not limited thereto.

As for 1, the one end 1A on the right side has a large diameter hole 1B, the other end 1C on the left side has a small diameter hole 1D, and the medium diameter hole 1E extends from the large diameter hole 1B toward the small diameter hole 1D. It is a distribution pipe body that has been drilled.

The large-diameter hole 1B and the medium-diameter hole 1E are provided with a locking step portion 1F.
These medium diameter holes 1E form a fuel chamber F, and the longitudinal axis XX of the fuel chamber F extends in the horizontal direction. The longitudinal axis XX of the distribution pipe body 1 is also the fuel chamber F.
The same axis as the longitudinal axis X-X.

Reference numeral 2 denotes a pair of guide grooves formed so as to face the inner peripheral surface 1G of the medium diameter hole 1E (in other words, the inner peripheral surface 1G of the fuel chamber F). a and a groove depth h, and extends along the longitudinal axis XX of the distribution pipe body 1.

3 is inserted into the large-diameter hole 1B, and the locking step portion 1
The partition body has a flange portion 3A disposed in contact with F and extends from the flange portion 3A into the fuel chamber F and is a plate-shaped member that is inserted and guided in the guide groove 2.

The partition body 3 will be described in more detail. Both lateral ends of the partition body 3 are guided by a pair of opposing guide grooves 2 to extend along the longitudinal axis XX of the distribution pipe body 1 and fixed. Further, the left end of the partition body 3 does not come into contact with the other end 1C of the distribution pipe body 1. That is, the gap S is formed.

By arranging the partition body 3 in the fuel chamber F of the distribution pipe body 1 as described above, the collar portion 3A of the partition body 3 abuts on the locking step portion 1F of the distribution pipe body 1, and Stop section 1F
The fuel chamber F that opens to the bottom is closed, while the fuel chamber F is
1 along the longitudinal axis XX of the distribution pipe body 1
It is divided into a secondary flow passage 4A and a secondary flow passage 4B, and the primary flow passage 4A and the secondary flow passage 4B are communicated with each other by a gap (S) in the vicinity of the other end 1C of the distribution pipe body 1. .. (The distribution pipe main body 1 is divided by the partition body 3 into the primary side flow passage 4A and the secondary side flow passage 4
It can be read as B. )

Regarding the gap (S), the end of the partition body 3 is brought into contact with the other end 1B of the distribution pipe body 1, and the partition body 3
The hole may be provided at the end of the hole, and can be replaced with other means.

A fuel inflow path 5 communicating with a fuel pump (not shown) is opened in the primary side flow path 4A located at one end 1A of the distribution pipe body 1 and located at one end 1A of the distribution pipe body 1. A fuel discharge passage 6 communicating with a pressure regulator (not shown) is opened in the secondary side passage 4B, and a plurality of fuel injection valves (not shown) are attached to the secondary side passage 4B. The fuel injection valve mounting hole 7 opens along the longitudinal axis XX of the distribution pipe body 1. In this example, the fuel injection valve mounting hole 7
Was drilled in 3 places.

Then, the first closing member 8 is arranged above the flange portion 3A of the partition 3 in the large diameter hole 1B to close the large diameter hole 1B, and the opening portion of the small diameter hole 1D is the second opening. It is closed by the closing body 9.

The fuel distribution pipe is formed as described above,
Particularly, the distribution pipe body 1 as shown in FIG. 3 is formed by injection molding of a synthetic resin material. Distribution pipe body 1
A mold assembly diagram for molding the will be described with reference to FIGS. 4 and 5.

Reference numeral 10 denotes a fixed die fixed to the molding machine, and the outer portion of the upper half of the distribution pipe body 1 is engraved on the die matching surface. (The outer part of the upper half is YY in FIG.
The outer part above. )

Reference numeral 11 denotes a movable mold which is moved by a molding machine and abuts against and separates from the fixed mold 10. The outer half of the lower half of the distribution pipe body 1 is engraved on the mold matching surface.
(The outer part of the lower half is the outer part below the Y-Y line in FIG. 3)

The fixed mold 10 and the movable mold 11 are brought into contact with each other at the mold matching surface N, whereby the shape of the outer portion of the distribution pipe body 1 (upper half and lower side) between the two molds 10 and 11. The shape of the combined half) can be defined.

Reference numeral 12 is a first movable core for forming the fuel chamber F, which is located between the fixed mold 10 and the movable mold 11 and is located between the mold matching surfaces N. Mold 11
The first movable core 12 is arranged so as to be movable rightward in FIG.

Reference numeral 13 denotes a second movable core which is arranged between the fixed mold 10 and the movable mold 11 and is movable between the fixed mold 10 and the movable mold 11 so as to move back and forth. It is arranged so as to face the first movable core 12 with a gap at the time of completion of mold matching, and in this example, it is arranged so as to be movable leftward in FIG. The tips of the first movable core 12 and the second movable core 13 should not be in direct contact with each other.

The tip end outer periphery 12A provided at the tip of the first movable core 12 has a first movable core tip fitting hole 13 formed at the tip of the second movable core 13 at the time of completion of mold matching.
It is fitted in A.

The molds 10 and 11 and the movable cores 12 and 13 are formed as described above, and a cavitation is formed in the mold as shown in FIG.

In the completed mold matching state, the distribution pipe body 1 shown in FIG. 3 could be molded by injecting a molten resin material into the cavities, cooling and solidifying and then opening the mold.

According to the above, when the mold matching is completed,
The outer periphery 12 of the tip end portion of the first movable core 12 forming the fuel chamber F
Since A can be securely fitted and fixed in the tip fitting hole 13A of the second movable core 13, even if the high-pressure molten resin is injected into the cavity, the first movable core 12 is fixed to the fixed mold 10. Since the movable mold 11 is prevented from swinging, a gap is not formed in the mating surface between the fixed mold 10, the movable mold 11 and the movable core, and at the time of molding, for example, the fuel injection valve mounting hole It was possible to completely prevent the occurrence of burrs at the opening to the fuel chamber.

The embodiment shown in FIG. 6 has the first movable core 1
The outer circumference 12A of the tip end portion 2 is directly supported by the fixed mold 10 and the movable mold 11 without using the second movable core 13, which makes the second movable core 13 unnecessary. As a result, the die manufacturing cost can be reduced, and the drive source for moving the second movable core 13 back and forth is not necessary, so that the die and device manufacturing costs can be reduced.

[0038]

As described above, the distribution pipe main body having the fuel chamber formed therein along the longitudinal axis XX and the pressurization discharged from the fuel pump with one end opened into the fuel chamber. A fuel inflow path for supplying fuel into the fuel chamber, a fuel discharge path for connecting the pressure regulator and the fuel chamber with one end opening into the fuel chamber, and a plurality of fuels connected with the fuel injection valve for opening one end into the fuel chamber. In a fuel distribution pipe formed of a synthetic resin material, which includes an injection valve mounting hole, a fixed mold,
At least an outer portion of the distribution pipe body is formed by a movable mold that is movably arranged so as to face the fixed mold, and the movable mold is movably arranged between the fixed mold and the movable mold. At least the fuel chamber is formed by the movable core, and the outer periphery of the tip end portion of the first movable core is arranged so as to be movable back and forth between the mold matching surfaces of the fixed mold and the movable mold, and faces the first movable core. By pressing and sandwiching it by the second movable core that is arranged in the same manner, the runout of the first movable core during molding can be completely eliminated. Since it was possible to completely suppress the gap generated on the mating surface with the child, it was possible to obtain a piping body that completely eliminated burrs generated at this part, and it was possible to achieve a significant reduction in manufacturing cost. ..

Further, a distribution pipe main body in which a fuel chamber is formed along the longitudinal axis XX, and one end opened into the fuel chamber, the pressurized fuel discharged from the fuel pump is supplied to the fuel chamber. To the fuel inflow path to supply to, and one end opens into the fuel chamber,
In a fuel distribution pipe formed of a synthetic resin material, a fuel discharge passage that connects the pressure regulator and the fuel chamber, and a plurality of fuel injection valve mounting holes that open at one end into the fuel chamber and are continuous with the fuel injection valve are provided. , The fixed mold and the movable mold that is movably arranged facing the fixed mold form at least the outer portion of the distribution pipe body, and can move back and forth between the mold matching surfaces of the fixed mold and the movable mold. At least the fuel chamber is formed by the first movable core that is disposed in the first movable core, and the outer periphery of the tip end portion of the first movable core is supported by the fixed mold and the movable mold. It is possible to suppress the above, and to reduce the cost of manufacturing the mold or the cost of manufacturing the molding machine.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an assembled state of a fuel distribution pipe.

FIG. 2 is a vertical cross-sectional view taken along the line PP of FIG.

FIG. 3 is a vertical cross-sectional view of the distribution pipe body in FIG.

FIG. 4 is a mold assembly diagram for molding a distribution pipe body.

5 is a vertical cross-sectional view taken along the line RR of FIG.

FIG. 6 shows another embodiment of a mold assembly diagram for molding the distribution pipe body.

[Explanation of symbols]

 1 minute piping main body 1A One end 1C The other end F Fuel chamber 5 Fuel inflow path 6 Fuel discharge path 7 Fuel injection valve mounting hole 10 Fixed mold 11 Movable mold 12 First movable core 12A First outer periphery of the first movable core 13 2nd movable core 13A Tip fitting hole of 2nd movable core

Claims (2)

[Claims] 1. A distribution pipe main body in which a fuel chamber is formed along a longitudinal axis XX thereof, and one end of which is opened into the fuel chamber to pressurize fuel discharged from a fuel pump into the fuel chamber. A fuel inflow path for supplying fuel to the fuel chamber, a fuel discharge path connecting one end to the fuel chamber and connecting the pressure regulator and the fuel chamber, and a plurality of fuel injection valve mounting holes connecting one end to the fuel chamber and connecting to the fuel injection valve. In the fuel distribution pipe formed of a synthetic resin material, a fixed mold and at least an outer portion of the distribution pipe main body is formed by a movable mold movably arranged facing the fixed mold. At least a fuel chamber is formed by a first movable core that is arranged to move back and forth between the mating surfaces of the fixed mold and the movable mold, and the outer periphery of the tip end of the first movable core is fixed to the movable mold. Made of synthetic resin that is pressed and clamped by the mold Manufacturing method of fuel distribution pipe. 2. A distribution pipe body in which a fuel chamber is formed along a longitudinal axis XX thereof, and one end of which is opened into the fuel chamber to pressurize fuel discharged from a fuel pump into the fuel chamber. A fuel inflow path for supplying fuel to the fuel chamber, a fuel discharge path connecting one end to the fuel chamber and connecting the pressure regulator and the fuel chamber, and a plurality of fuel injection valve mounting holes connecting one end to the fuel chamber and connecting to the fuel injection valve. In the fuel distribution pipe formed of a synthetic resin material, a fixed mold and at least an outer portion of the distribution pipe main body is formed by a movable mold movably arranged facing the fixed mold. At least a fuel chamber is formed by a first movable core that is arranged to move back and forth between the mating surfaces of the fixed mold and the movable mold, and the outer periphery of the tip end portion of the first movable core is movable with the fixed mold. It is placed so that it can move back and forth between the mating surfaces with the mold. And a synthetic resin fuel distribution pipe supported by a second movable core that is disposed opposite to the first movable core.