JPS6059427B2 - Delivery pipe in fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device, and particularly to the structure of a delivery pipe that supplies fuel to an injection valve (injector) of the fuel injection device.

It is widely known that a carburetor is normally used as a fuel supply means for a gasoline engine, but recently there has been a trend to adopt a fuel injection method for the purpose of reducing exhaust gas and improving fuel efficiency.

This fuel injection device is equipped with an injection valve (injector) that can be electromagnetically controlled to open and close on the intake manifold of each cylinder, and injects a predetermined amount of fuel into the intake manifold from this injection valve according to the intake air amount and engine operating conditions. It is now being injected into the air. By the way, since the injection valve is connected to the fuel pump via the delivery pipe, fuel pressurized to a constant pressure is distributed through the delivery pipe.

Therefore, this type of delivery pipe is required to have a high degree of liquid tightness. When this type of delivery pipe is constructed by cutting an extruded aluminum material into the required length, the openings at both ends of the delivery pipe must be closed liquid-tight, and usually a stopper is attached to this opening. In some cases, it is blocked. As a conventional plug mounting structure, there is a structure in which female threads are cut on the inner circumferential surface of the opening at both ends of a delivery pipe, and an iron plug is screwed into the threaded portions via an O-ring. This structure has advantages such as high seal reliability, but due to the structure in which the internal thread is carved into the delivery pipe, the pipe itself needs to have a certain wall thickness, and in order to secure the threading amount, This increases the axial length of the delivery pipe, which not only increases weight but also complicates the structure and increases cost. Another example is one in which plugs made of different metals are welded to the openings at both ends of the delivery pipe.

According to this structure, compared to the one in which the plug body is screwed in,
It has the advantage of simplifying the structure of the plug attachment part and making the delivery pipe lighter and more compact.
Cost-related problems remain, such as requiring expensive manufacturing equipment and making it unprofitable unless mass-produced. As a countermeasure to this problem, welding an aluminum stopper may be considered, but this tends to cause pinholes and the like to occur in the welded portion, resulting in problems such as a decrease in the reliability of the seal.

The present invention was made based on these circumstances, and
The purpose is to have a simple structure and a small number of parts.
The present invention aims to provide a delivery vibe for a fuel injection device that not only reduces costs but also makes the delivery vibe more compact and has a highly reliable seal and is safe.

That is, in order to achieve the above object, the present invention comprises a delivery vibe made of an extruded aluminum material having a through hole inside, and the openings at both ends of the through hole are formed on the outer circumferential surface in the circumferential direction. It is closed by inserting an aluminum plug with a continuous groove, and this plug is fixed with an adhesive applied to the outer circumferential surface of the plug on the outside of the groove in the direction of insertion. , and in a state in which the plug is inserted, the openings at both ends of the through hole are caulked to prevent the plug from coming off.

The present invention will be explained below based on an embodiment shown in the drawings.

FIG. 1 shows a 4-cycle, 4-air engine that employs a fuel injection system, where 1 is a cylinder block, 2 is a cylinder head, 3 is a piston, and 4 is a combustion chamber.

The cylinder head 2 is provided with an exhaust valve 9 that opens and closes an exhaust boat 5 provided in the combustion chamber 4, and an intake valve 10 that opens and closes the intake boat 6. 11 and an intake cam 12 to open and close the valve. An intake manifold 13 is connected to the four intake boats 5 (only one is shown) of the cylinder head 2, and the two ends of the intake manifold 13 on the intake boat 5 side include:
An injection valve (injector) 14 is attached to each of them. This injection valve 14 is not shown in detail, but its internal discharge valve is electromagnetically controlled to open and close based on commands from an electronic control unit, and four nozzle portions at the tips are introduced into the intake manifold 13. A delivery vibe 15 that distributes and supplies fuel to each injection valve 14 is connected to the base end of the injection valve 14 . This delivery vibe 1
If the structure of 5 is explained with reference to FIGS. 2 to 9, 16 is the main body of the vibrator, and the main body 1
6 is constructed by dividing an extruded material 17 made of aluminum or aluminum alloy into required lengths. Inside the extruded material 17, along the longitudinal direction,
Through holes 18 are provided at both end faces of the extruded material 17, and the through holes 18 are integrally formed when the extruded material 17 is extruded. Four mounting holes 1) 9 corresponding to the number of cylinders are formed in one end surface of the vibrator body 16. These mounting holes 19 communicate with the through hole 18, and the base end of the injection valve 14 is connected thereto. The opening sides of both ends of the through hole 18 are formed with a large inner diameter to form a mounting portion 20, into which a plug 21 for closing the opening is press-fitted. The plug body 21 is made of the same kind of aluminum or aluminum alloy as the vibrator body 16, and a concave groove 22 continuous in the circumferential direction is carved in the middle of the outer peripheral surface of the plug body 21. An anaerobic adhesive such as Loctite is applied seamlessly to the outer circumferential surface 23 of this plug body 21 on the outside in the press-fitting direction from the concave groove 22, so that the plug body 21 It is fixed in the mounting part 20 by the above-mentioned press-fitting and adhesive, and the openings at both ends of the through hole 18 are liquid-tightly sealed. It constitutes a fuel passage 24 as a space through which fuel flows.The groove volume of the groove 22 is set to be larger than the amount of adhesive applied to the outer peripheral surface of the plug body 21. When the plug body 21 is press-fitted, the adhesive applied to the outer peripheral surface is prevented from flowing inside the groove. After that, it is caulked using a jig 25. This jig 25 has four punch parts 26 arranged side by side at equal intervals in the circumferential direction, and the punch parts 26... By pressing the opening edge in the axial direction, caulking portions 27 protruding inward are formed at four locations spaced apart by 90 mm in the circumferential direction on the opening edge of the through hole 18. These caulking parts 27...
* is engaged with the outer end surface of the plug body 21 to hold the plug body 21 in the mounting portion 20 so as not to come off. Further, on the end surface of the vibrator main body 16 opposite to the side where the mounting holes 19... are opened, screw holes 28, 28 are opened at both ends along the longitudinal direction. hole 28,
28 communicates with the through hole 18, that is, the fuel passage 24.

And the screw holes 28, 28 have fuel vibes 29, 29, respectively.
is connected. One fuel vibe 29 is connected to a fuel tank via a fuel pump (not shown) to constitute a fuel delivery path, while the other fuel vibe 29 is connected to the fuel tank to constitute a fuel return path, and the other fuel vibe 29 is connected to the fuel tank to constitute a fuel return path. The fuel passage 24 is filled with fuel at a constant pressure pressurized by a fuel pump. However,
According to this configuration, the plug body 21 is fixed to the openings at both ends of the through hole 18 by a combination of press-fitting and adhesive, and the openings at both ends of the through hole 18 are liquid-tightly sealed. As a result, the seal structure becomes double, improving the reliability of the seal.

Moreover, after the plug body 21 is press-fitted into the openings at both ends of the through-hole 18, it is held in place by caulking the opening edges of the through-hole 18, so that the tightening effect due to the press-fitting and the adhesive strength of the adhesive are maintained. Together with this, the fixation is ensured and the reliability of the seal is further improved. Further, there is no need to provide a threaded portion on the vibrator body 16 or the plug body 21 unlike the conventional structure in which the plug body is screwed in, and since the O-ring can also be omitted, the structure can be simplified and the number of parts can be reduced. Furthermore, compared to welding the plug, it is easier to work with and does not require large-scale equipment, so manufacturing costs can be reduced. Therefore, as can be seen from the above description, this structure has the advantage of improving the reliability of the seal and making the delivery vibe 15 more compact, as well as solving cost problems.

Further, a concave groove 22 is provided on the outer peripheral surface of the plug body 21, and
The adhesive is applied to the outer circumferential surface 23 on the outside of this groove 22 in the press-fitting direction.
Since the adhesive is applied to the fuel passage 24, this adhesive is prevented from flowing into the fuel passage 24.

That is, when the plug body 21 is fixed with an anaerobic adhesive, if this adhesive adheres to the portion facing into the fuel passage 24, this adhesive reacts with the fuel and becomes jelly-like.
This jelly-like reactant is mixed with fuel at the injection valve 14.
This may lead to clogging of the injection valve 14. However, according to this configuration, even if the adhesive tries to flow out to the fuel passage 24 side, this adhesive will not flow into the groove 22.
Since the concave groove 22 prevents the fuel from flowing out to the fuel passage 24 side, there is no risk of it reacting with the fuel, and therefore, the injection valve 14 will not be clogged. In the present invention described in detail above, the delivery vibe is constructed of an extruded aluminum member having a through hole therein as a fuel passage, and the openings at both ends of the through hole extend in the circumferential direction on the outer peripheral surface. The plug is closed by inserting an aluminum plug with a continuous groove, and this plug is fixed with an adhesive applied to the outer peripheral surface of the groove on the outside in the direction of insertion. When the plug is inserted, the openings at both ends of the through hole are caulked to prevent the plug from coming off.

According to this, the plug is fixed by caulking in addition to the adhesive force of the adhesive, so that the plug is securely fixed and the reliability of the seal is greatly improved. Moreover, unlike the conventional structure where the plug is screwed in, there is no need to thread the delivery vibe or the plug itself, and the O-ring can also be omitted, simplifying the structure and reducing the number of parts. Can be configured compactly. In addition, even when compared with a structure in which the plug body is welded, it is easier to work with and does not require large-scale manufacturing equipment, so manufacturing costs can be reduced. In addition, since there is no risk of the adhesive flowing out to the fuel passage side beyond the groove, there is no possibility that the fuel and adhesive will react and produce a jelly-like solid. Even though the injection valve is stuck, it has excellent effects such as no clogging of the injection valve.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a cross-sectional view of an internal combustion engine employing a fuel injection system, Fig. 2 is a front view of a delivery pipe, and Fig. 3 is a line 1 in Fig. 2. A cross-sectional view along
Figure 4 is a cross-sectional view along the line ■-■ in Figure 2, and Figure 5 is a cross-sectional view of the
Figure 6 is a cross-sectional view taken along line ■-■ in Figure 2, Figure 7 is a cross-sectional view that does not show the state in which the plug is attached, and Figure 8θ is a cross-sectional view of the plug. Cross-sectional view showing the fixed state, No. 9
The figure is a view taken along the line ■-■ in FIG. 4... Cylinder (combustion chamber), 13... Intake passage (intake manifold), 14... Injection valve, 15... Delivery vibe, 17... Extruded material, 18... Through hole, 2
1... Plug body, 22... Concave groove, 24... Fuel passage,
27...Caulking part.

Claims (1)

[Claims] 1 In a delivery pipe that is equipped with a fuel passage through which fuel at a constant pressure is distributed and which is connected to a plurality of injection valves provided in each cylinder or intake passage of an internal combustion engine, and distributes and supplies fuel to the injection valves, this delivery pipe is An extruded aluminum material having a through hole as the fuel passage inside is divided into required lengths, and the openings at both ends of the through hole are provided with concave grooves continuous in the circumferential direction on the outer peripheral surface. It is closed by inserting an aluminum plug, and this plug is fixed to the openings at both ends of the through hole with an adhesive applied to the outer peripheral surface on the outer side in the insertion direction than the groove. 1. A delivery pipe for a fuel injection device, characterized in that the plug body is fixed to prevent it from coming off by caulking both end openings of the through hole in a state in which the plug body is inserted.