JP2873975B2 - Fuel delivery pipe and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a fuel delivery pipe composed of a cylindrical hollow socket and a communication pipe, and more particularly, to a body part having a circular cross section. A method of manufacturing a fuel delivery pipe formed by connecting a plurality of sockets, each having a circular pipe having an outer diameter smaller than the outer diameter of the portion projecting in the right and left directions at right and left sides by using a communication pipe, and this manufacturing method It relates to the fuel delivery pipe obtained.

(Prior Art) FIG. 9 shows a typical structure of a fuel delivery pipe for injecting fuel toward three cylinders on one side of a fuel injection V-type six-cylinder engine. The fuel delivery pipe 90 is connected so that three cylindrical sockets 91 for receiving the introduction shaft (cylindrical portion) of the fuel injector communicate with each other through a communication pipe 92 at regular intervals. It is arranged. These sockets 91 are made by cutting a forged product, and a part of the inner surface receives the O-ring on the fuel injector side and has extremely high roundness and burnishing to achieve perfect liquid tightness. Processing is applied.

An opening is formed in the cylindrical wall 93 of each socket in a direction perpendicular to the central axis and penetrating the center of the diameter or a position slightly eccentric, and the continuous end of the communication pipe 92 will fit into this opening. It is fixed by the attaching portion 94. At the upper end of the cylindrical wall 93, there are provided flange portions 95 having bolt holes on the right and left sides, respectively, so that a cap for fixing the fuel injector can be tightened with screws.

The fuel delivery pipe shown in FIG. 9 is of a type called a bottom flow type. Since fuel passes through the center of the socket and is injected, it is hardly affected by vapor, and the mounting height is low. There is an advantage that it can be reduced.

Since the conventional bottom flow type fuel delivery pipe is configured as shown in FIG. 9, a complicated work for brazing is required for the connection work between the socket and the communication pipe, and further, the space between the sockets is required. Strict dimensional accuracy is required for the spacing and the mounting angle, so that a large number of man-hours are required for the assembling work and inspection, resulting in an increase in cost.

In particular, when a pipe having a circular cross section is inserted into a cylindrical wall of a socket having a circular cross section for connection, it is well known that the connection portion has a plurality of saddle shapes. Various proposals have been made for the structure of the connection portion.

For example, Japanese Utility Model Publication No. 43-5515 "Exhaust stack" and Japanese Utility Model Publication No. 49-11
No. 84420, "Connecting Structure of Branched Capillary Tube and Base Pipe", proposes a method of connecting pipes by bending the wall surface.

However, in order to form the protruding portion by bending the wall surface of the pipe in a saddle shape in this way, the thickness of the pipe must be small, and a thick pipe for high temperature and high pressure or vibration It cannot be applied to such piping.

Since the fuel delivery pipe and the like used for fuel injection of the engine as shown in FIG. 9 must withstand the high temperature of the engine and withstand strong vibration, the connection method described above is used because the wall thickness becomes large. Can not do. For this reason, although the cutting process or the cutting process is performed so that the connection portion of the two circular cross-section cylindrical portions to be connected has an accurate saddle shape, a gap is formed when both cylindrical portions are connected. However, there was a drawback that welding was incomplete and oil leakage was caused.

Further, when connecting the pipe and the left and right sockets, there is a disadvantage that the phase of the angle is shifted due to the twist in the rotational direction.

A method has been proposed in which a ring-shaped bead portion is provided around the periphery of the end of the pipe on the insertion side and this is used as a stopper. There is a disadvantage that the phase is not determined. Also, if the tip of the pipe on the insertion side remains cut off at a right angle, it will protrude into the inner surface of the pipe on the receiving side without conforming to the inner shape of the pipe, obstructing the cross section of the flow path and hindering insertion of the fuel injector become.

Therefore, a branch socket with a shape in which circular pipes project at right and left from the body part having a circular cross section to the right and left, respectively, is formed as an integral type by cold forging or hot forging, and cutting is performed to add a branch. A method of completing a socket with a hole has been proposed.

However, in the case of such forging, it is difficult to process a product having a biased wall thickness by cold forging, so that the wall thickness is left in an unnecessary portion, and the number of steps of the cutting process is increased. Therefore, in the case of cold forging, it is difficult to directly forge a socket with branches.

On the other hand, when hot forging is used, the outer shape of the socket with branches can be formed, but the space in the center cannot be formed, and a step of cutting out the center by cutting is required. Will further increase.

(Problems to be Solved by the Invention) An object of the present invention is to reduce a part of complicated processing steps, reduce the number of processing steps, and reduce costs.

Another object of the present invention is to provide a manufacturing method that can easily cope with fuel delivery pipes having different specifications.

(Means for Solving the Problems and Their Functions) The above-mentioned object of the present invention is, in the first mode,
A cylindrical socket body is formed by cold forging from a rod-shaped material, and a socket branch is formed by cold forging from a rod-shaped material, and the socket body and the socket branch are brazed and / or welded. And a through hole penetrating through the socket body portion and the socket branch portion, and communicating with the hollow socket by performing brazing or welding with one end of the communication pipe inserted into the socket branch portion. This is achieved by a method of manufacturing a fuel delivery pipe that integrates a tube, thereby forming an integrated fuel delivery pipe.

Based on such a structure, according to the processing method of the present invention, the socket branch portion is joined to the cylindrical socket body portion. One end of the branch portion is formed into a saddle shape at the time of cold forging, and the other is formed into a shape which is simultaneously cut off into a vertical cylindrical shape.

There is no need to pre-drill a hole in the socket body to insert the branch. Further, the socket branch portion is formed without a through hole, and after joining to the socket body portion, a hole penetrating both is formed, so that the hole processing is facilitated. Prior to the drilling, a centering recess is preferably provided in the center of the socket branch portion in advance.

Conventionally, a saddle-shaped hole was machined on the body part side, and the end of the communication pipe was cut in a saddle shape. Therefore, cutting or cutting by a plurality of strokes was necessary, and saddles on the left and right (both ends) were required. Although the phase of the shape had to be processed with high precision, the method of the present invention allows the through hole to be processed in one stroke, and the processing time is significantly reduced.

In the fuel delivery pipe, the center axis of the body portion and the center axis of the branch portion are often offset from each other because the jet flow must be rotated inside the socket.
In such a case, conventionally, the position of the hole in the body portion had to be changed in accordance with each offset amount, and a lot of man-hours were required for setting and inspecting the jig. According to the method of the present invention, since it is not necessary to make a hole in the body portion in advance, it is possible to easily cope with a fuel delivery pipe having a different specification, thereby reducing the cost.

According to a second aspect of the present invention, in a fuel delivery pipe composed of a cylindrical hollow socket and a communication pipe, a cylindrical socket body portion formed by cold forging a rod-shaped material, and a rod-shaped A socket branch portion formed by cold forging from a material and fixed to the socket body portion; a through hole passing through the socket body portion and the socket branch portion; A fuel delivery pipe including a communication pipe integrated with a hollow socket by brazing or welding with one end inserted.

This fuel delivery pipe is easy to process, reduces costs, and can easily cope with different specifications.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

(Embodiment) FIGS. 1 to 3 show the whole of a fuel delivery pipe 10 manufactured by the manufacturing method according to the present invention. The fuel delivery pipe 10 is used for supplying fuel to four cylinders on one side of a V-type eight-cylinder engine.

The fuel delivery pipe 10 includes four hollow sockets 21 arranged at predetermined intervals, communication pipes 22, 23, 24, and fittings 25, 26 attached to the fuel inlet and outlet sides,
It is composed of an inlet pipe 27 and an outlet pipe 28 connected to the respective fittings, and two brackets 29 fixed to the communication pipe.

FIG. 4 shows a method of manufacturing the hollow socket 21.
The socket 21 is brazed and / or brazed with a socket body part 31 formed by a cold forging from a rod-shaped material into a hollow cylindrical shape, and a socket branch part 32, 33 similarly formed by a cold forging from a rod-shaped material. It is formed by welding.

After the two are fixed, a through hole 41 is formed by a drill or the like along the central axis of the branch portion.
Is bored in a state where the axis 36 is offset from the center axis 35 of the cylindrical body portion 31 by the dimension E. That is, the hatched portions in FIG. 4 are cut off at this stage. However, a step for a stopper can be formed inside the through hole as described later.

The upper end of the body portion 31 is formed with a flange 38, and the left and right protruding portions are provided with screw holes 39 for tightening the injector, respectively.

FIG. 5 shows a longitudinal section along the line AA in FIG. 4, and FIG. 6 shows a longitudinal section along the line BB in FIG. If the stepped portion 43 is left inside when the through hole 41 is opened, it can be used as a stopper for inserting the end of the communication pipe 22 as shown in FIG. Assembly is facilitated. According to the present invention, since the communication pipes 22, 23, 24 (FIG. 1) are brazed or welded while being inserted into the branch portions of the hollow sockets, respectively, the connection pipes can be formed as in the prior art. It is possible to completely prevent oil from leaking from the gap.

7 and 8 show another embodiment of the hollow socket. In this embodiment, the screw hole 39 of the flange surface 38 of the socket body is mounted at an angle offset from the center axis 35 of the body. ing. Since the specification of the fuel delivery pipe is determined according to the shape of the corresponding engine, it is preferable that the fuel delivery pipe has a structure that can be applied to various specifications. According to the present invention, since the trunk portion and the branch portion are formed separately, it is possible to meet a wide range of specifications by replacing one of them.

(Effects of the Invention) As described above in detail, according to the present invention, the number of processing steps is greatly reduced, the number of steps is simplified, and the manufacturing cost is reduced. In particular, since the phase shift of the angle is eliminated, a fuel delivery pipe that can conform to various specifications with high accuracy is realized. In addition, the technical effect is extremely remarkable, such as oil leakage from a joint portion between the communication pipe and the hollow socket is completely prevented to improve reliability.

[Brief description of the drawings]

1 is a front view showing the entire fuel delivery pipe according to the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a left side view thereof, FIG. 4 is an enlarged plan view showing a method of manufacturing a hollow socket, 5 is a longitudinal sectional view taken along line AA in FIG. 4, FIG. 6 is a longitudinal sectional view taken along line BB in FIG. 4, and FIG. 7 is a plan view showing another embodiment of the hollow socket. FIG. 8, FIG. 8 is a front view, and FIG. 9 is a perspective view showing a conventional fuel delivery pipe. 10 Fuel delivery pipe 21 Hollow socket 22, 23, 24 Communication pipe 27 Inlet pipe 28 Outlet pipe 31 Socket body part 32, 33 Socket branch part 35, 36 Center axis line 41: Through-hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02M 55/02

Claims (3)

(57) [Claims] 1. A method of manufacturing a fuel delivery pipe comprising a cylindrical hollow socket and a communication pipe, comprising: forming a cylindrical socket body by cold forging from a rod-shaped material; Forming a socket branch portion by inter-forging, fixing the socket body portion and the socket branch portion by brazing and / or welding, and forming a through hole penetrating the socket body portion and the socket branch portion. The hollow socket and the communication tube are integrated by brazing or welding with one end of the communication tube inserted into the socket branch portion, thereby forming an integral fuel delivery pipe. A method for manufacturing a fuel delivery pipe. 2. The manufacturing method according to claim 1, wherein the fixing is performed with the center axis of the body portion and the center axis of the branch portion being offset. 3. A fuel delivery pipe comprising a cylindrical hollow socket and a communication pipe, wherein: a cylindrical socket body portion formed by cold forging from a rod material; and a cold forging from a rod material. A socket branch part formed by the following and fixed to the socket body part; a through hole passing through the socket body part and the socket branch part; and one end of the communication pipe inserted into the socket branch part. A fuel delivery pipe comprising a hollow socket and a communication pipe integrated with the hollow socket in a state by brazing or welding.