JPH0649897Y2 - Structure of fuel delivery pipe in internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a fuel delivery pipe for distributing and supplying fuel from a fuel pump to fuel injection valves in respective cylinders of a fuel injection type internal combustion engine. Related to the improvement of.

[Conventional technology and its problems]

Conventionally, a fuel injection valve is connected to a fuel delivery pipe by forming an insertion hole in a direction perpendicular to the axis of the fuel delivery pipe in a connection boss portion integrally formed on the outer peripheral surface of the fuel delivery pipe.
The fact that the connector portion at one end of the fuel injection valve is detachably inserted into this insertion hole is well described, for example, as described in Japanese Utility Model Laid-Open No. 57-78769. Are known.

On the other hand, as shown in FIGS. 4 and 5, the fuel delivery pipe is usually manufactured by casting or die-casting with a circular cross section. Therefore, the fuel delivery pipe A is integrally molded. The inner surface c of the insertion hole C in the connecting boss B is finished by machining after casting or die-casting of the fuel delivery pipe A to an inner diameter dimension that exactly matches the outer dimension of the connector portion of the fuel injection valve. It is to be processed.

When finishing the inner surface c of the insertion hole C, of the opening edge portion of the insertion hole C into the fuel delivery pipe A,
There is a possibility that a large amount of machining burr E will be generated in the portion D where the inner surface c of the insertion hole C and the inner surface a of the fuel delivery pipe A form an obtuse angle, and the machining burr E may cause a problem such as clogging of the fuel injection valve. Therefore, this processing burr E is formed on the inner surface c of the insertion hole C.
It must be removed after the finishing process.

However, since the opening corner edge portion of the insertion hole C into the fuel delivery pipe A has a three-dimensionally curved shape, the processing burr E generated in this portion is cut off by mechanical chamfering processing. This is extremely difficult, and since it has to be cut out by a manual process such as sanding by hand, it takes a lot of time and labor, which causes a significant increase in cost. .

The present invention provides a fuel delivery pipe having a structure capable of reducing the machining burr generated at the opening edge portion of the insertion hole and facilitating the cutting of the machining burr even when the machining burr is generated. That is the purpose.

[Means for solving problems]

In order to achieve this object, the present invention has a circular cross section, and integrally forms a connecting boss portion on the outer periphery, and has an insertion hole for inserting a fuel injection valve in this connecting boss portion. In a fuel delivery pipe made by casting or die-casting, in a portion of the inner surface of the fuel delivery pipe where the insertion hole opens with respect to the inner surface, a recess formed into a flat surface substantially perpendicular to the axis of the insertion hole, The fuel delivery pipe is formed when it is cast or die-cast.

[Function and effect of device]

As described above, in the inner surface of the casting or die-cast fuel delivery pipe having a circular cross section, the recess having a flat surface substantially perpendicular to the axis of the insertion hole is formed in the portion where the insertion hole is opened with respect to the inner surface. When the delivery pipe is formed during casting or die casting, the insertion hole opens in the flat surface of the recess, so that the opening edge edge of the insertion hole into the fuel delivery pipe is the entire inner surface of the insertion hole. Since there is no part that becomes a right angle over the circumference and has an obtuse angle as in the conventional case, during finishing processing on the inner surface of the insertion hole, processing burr generated at the edge portion of the opening of the insertion hole to the fuel delivery pipe is reduced. And you can also
Since this opening corner edge is a straight line parallel to the plane perpendicular to the axis of the insertion hole, even if a machining burr is generated on the opening corner edge, the machining burr is mechanically different from the opening corner edge. It can be cut very easily by various chamfering processes.

Therefore, according to the present invention, there is an effect that it is possible to reduce the processing cost of the fuel delivery pipe made of cast or die cast.

〔Example〕

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 3). Reference numeral 1 denotes a fuel delivery pipe made by casting or die casting, and the fuel delivery pipe 1 has an outer peripheral surface,
A plurality of boss portions 2 for connecting a fuel injection valve to each cylinder in an internal combustion engine and a mounting seat 7 are integrally provided and are formed in a circular cross section.

Each of the bosses 2 is formed with an insertion hole 3 of the fuel injection valve so that its axis 3a is perpendicular to the axis 1a of the fuel delivery pipe 1, and the inner surface 3b of the insertion hole 3 is , Finished to an inner diameter that exactly matches the outer dimensions of the connector of the fuel injection valve.

Then, in the inner surface of the fuel delivery pipe 1, at a portion where each of the insertion holes 3 opens with respect to the inner surface, a recess 4 having a flat surface 5 that is substantially perpendicular to the axis 3a of each of the insertion holes 3 is formed. , The fuel delivery pipe 1 is formed at the same time when the fuel delivery pipe 1 is cast or die cast.

With this configuration, the fuel delivery pipe 1 of each insertion hole 3
The angled edge portion 6 that opens inward becomes a right angle over the entire circumference of the inner surface 3b of each insertion hole 3 and there is no obtuse angle portion as in the conventional case. Therefore, when finishing the inner surface 3a of each insertion hole 3 It is possible to reduce the processing burr generated at the opening corner edge 6 of the insertion hole 3 to the fuel delivery pipe 1, and the opening corner edge 6 is perpendicular to the axis 3a of the insertion hole 3. Since it is a straight line parallel to the flat surface, even if a machining burr is generated on the opening corner edge 6, the machining burr can be cut off very easily by mechanical chamfering of the opening corner edge 6. Can be done.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a partially cutaway front view of a fuel delivery pipe, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. 3 is FIG. III-III enlarged cross-sectional view of FIG. 4, FIG. 4 is an enlarged view of a main part of a conventional fuel delivery pipe, and FIG. 5 is a VV cross-sectional view of FIG. 1 ... Fuel delivery pipe, 1a ... Fuel delivery pipe axis,
2 ... connection boss, 3 ... insertion hole, 3a ... insertion hole axis, 3b ... insertion hole inner surface, 4 ... recess, 5 ... flat surface.

Claims (1)

[Scope of utility model registration request] 1. A casting or die-cast product having a circular cross section, a connection boss portion integrally formed on the outer periphery, and an insertion hole for inserting a fuel injection valve formed in the connection boss portion. Of the fuel delivery pipe, the fuel delivery pipe is formed at a portion of the inner surface of the fuel delivery pipe where the insertion hole opens with respect to the inner surface, when the fuel delivery pipe substantially perpendicular to the axis of the insertion hole is cast or die-cast. A structure of a fuel delivery pipe in an internal combustion engine characterized by the above.