JPH11270442A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve of an internal combustion engine, in which the acceptability of sealing for the connection part with a fuel supply pipe can be inspected accurately. SOLUTION: A fuel injection valve is configured so that an O-ring 5 to seal the peripheral surface 33a of the base end 3 and the internal circumferential surface 7a of the outgoing end 7 of a fuel supply pipe is furnished at the peripheral surface of the base end of a fuel injection valve 1 so as to ensure the air-tightness and a step 31 for location of the O-ring 5 is formed on the peripheral surface 33a of the base end 3, wherein a groove 32 stretching in the direction crossing the O-ring 5 is provided in the step surface 31a which supports the O-ring 5, while a gap S stretching in the direction crossing the O-ring 5 is formed between the O-ring 5 and step surface 31a, and thereby communication is generated between the inside and outside of the contact surface part of the O-ring 5 with step surface 31a so as not to establish the sealed condition even if the O-ring 5 is put in tight attachment to the step surface 31a, and thus it is possible to accurately judge the acceptability of sealing for the peripheral surfaces 33a and 7a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine, and more particularly to the prevention of occurrence of erroneous determination in an airtight inspection of the fuel injection valve.

[0002]

2. Description of the Related Art In an internal combustion engine, a fuel injection valve is connected to a fuel supply pipe for supplying fuel to the fuel injection valve by connecting a base end of the fuel injection valve where a fuel inlet is formed to an outlet end of the fuel supply pipe. It is performed by fitting. An O-ring made of rubber or the like is tightly fitted to the outer periphery of the base end of the fuel injection valve so as to seal the peripheral surface of the base end of the fuel injection valve and the inner peripheral surface of the outlet end of the fuel supply pipe. Has become. In addition, the base end generally forms a step with a small diameter on the fuel inlet side, and an O
The ring is supported and positioned.

[0003] The quality of the seal by the O-ring is checked in an airtight inspection before the fuel injection valve is actually connected to the fuel supply pipe. For example, a fuel injection valve is connected to a cap-shaped inspection jig simulating an outlet end of a fuel supply pipe via an O-ring, immersed in oil, and air is fed into the inspection jig. It is determined by observing whether or not air bubbles or the like are generated at the connection portion between the inspection tool and the inspection jig.

[0004]

However, at the time of airtight inspection,
Poor sealing between the O-ring and the inspection jig can be determined by the occurrence of air bubbles and the like. However, even if the sealing property between the O-ring and the peripheral surface of the base end portion is poor, if the sealing property between the O-ring and the stepped surface is good, no bubbles are generated. Therefore, even if the sealing property between the O-ring and the peripheral surface of the base end portion is poor, if the sealing properties between the O-ring and the inspection jig and between the O-ring and the stepped surface are good, bubbles are generated. Therefore, the fuel injection valve is determined to have good sealing performance.

When the fuel injection valve determined in this way is installed in an actual vehicle, under severe operating conditions of the internal combustion engine,
If the O-ring vibrates along the peripheral surface of the base end portion of the fuel injection valve and loosens between the step surface and the O-ring, complete sealing performance may not be secured.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a fuel injection valve capable of accurately determining whether an O-ring seal, particularly a seal between a peripheral surface of a base end portion and an O-ring, is good in an airtight inspection.

[0007]

According to the first aspect of the present invention, a fuel injection valve has a base end having a fuel inlet formed therein, fitted into an outlet end of a fuel supply pipe, and provided on an outer periphery of the base end. The O-ring keeps airtight, and a step for positioning the O-ring is formed on the peripheral surface of the base end. In addition to this configuration, a groove is provided on the step surface of the step portion supporting the O-ring in a direction crossing the O-ring.

A gap is formed between the O-ring and the step surface in a direction crossing the O-ring by the groove. Even if the O-ring is in close contact with the step surface, the gap allows the inside and outside of the O-ring to sandwich the contact portion, and thus no sealing is performed on the step surface. Therefore, if the seal between the peripheral surface of the base end portion and the O-ring is defective, it can always be found at the time of airtightness inspection.

According to the second aspect of the present invention, one end of the groove is opened in the peripheral surface of the base end portion, so that the O-ring is in contact with the step surface of the O-ring regardless of any deformation. The inside and outside communicate reliably.

[0010]

FIG. 1 shows an overall side view of a fuel injection valve of an internal combustion engine according to the present invention, and FIG. 2 shows a cross section of the fuel injection valve along the line AA in FIG. The fuel injection valve basically has the structure of a normal electromagnetic fuel injection valve. A fuel flow path 1c (see FIG. 2) is formed along the axis, and the fuel injection valve communicates with the injection hole 1a of the distal end portion 2. I have. The base end 3 of the fuel injection valve 1 is a portion connected to the outlet end 7 of the fuel supply pipe indicated by a phantom line. The base end 3 is provided with a supply port 1b serving as a fuel intake port. The fuel is delivered to the flow path 1c.
A connector 4 for power supply protrudes slightly diagonally above the base end 3.

A base end 3 of the fuel injection valve 1 is provided with a fuel supply port 1.
The step 31 is formed with the b side as the small diameter portion 33 and the tip 2 side as the large diameter portion 34. An O-ring 5 for sealing and a ring 6 for preventing the O-ring 5 from coming off are provided coaxially with the base end portion 3 on the outer periphery of the small diameter portion 33 of the base end portion 3. The ring 5 is inserted into the small-diameter portion 33 to abut against the step surface 31a of the step portion 31 for positioning, and then the ring 6 is inserted into the annular groove (not shown) formed in the peripheral surface 33a of the small-diameter portion 33 to form a base. Secure to end 3.

The O-ring 6 fits the base end 3 of the fuel injection valve 1 into the outlet end 7 of the fuel supply pipe and connects the fuel injection valve 1 to the outlet end 7 of the fuel supply pipe. The radial surface of the fuel injection valve 1 is compressed in the radial direction,
a and the peripheral surface 7a inside the outlet end portion 7 of the fuel supply pipe, and an annular contact surface is formed between the peripheral surfaces 33a and 7a to maintain airtightness.

A groove 32 is provided in the annular step surface 31a of the base end portion 3 in the width direction thereof. One end of the groove 32 reaches the outer peripheral edge of the step surface 31 and is formed on the peripheral surface 34a of the large diameter portion 34. It is open and the other end of the groove 32 reaches the inner peripheral edge of the annular step surface 31a. The groove 32 forms a gap S between the O-ring 5 and the annular step surface 31 a in a direction crossing the O-ring 5.
Due to the gap S, a corner C formed by the annular step surface 31a, the peripheral surface 33a of the small diameter portion 33, and the O-ring 5, and the outside that sandwiches the annular contact surface between the O-ring 5 and the annular step surface 31a. Are connected.

The cross-sectional shape of the groove 32 can be any shape such as a quadrangle or a triangle. The number of the grooves 32 is one in the illustrated example, but may be plural.

An airtight inspection of the fuel injection valve 1 will be described with reference to FIGS. FIG. 3 shows the base end 3 side at the time of the airtightness inspection of the fuel injection valve 1. In order to inspect the airtightness of the fuel injection valve 1, a cap-shaped simulating the outlet tip 7 (FIG. 1) of the fuel supply pipe is provided at the base end of the fuel injection valve 1 as in the case of the conventional fuel injection valve. The inspection jig 8 (FIG. 3) is covered, and air or the like is fed into the inspection jig 8 to check whether there is any leakage of the air or the like. Leakage of air or the like flows out between the inspection jig 8 and the base end 3 of the fuel injection valve 1 as indicated by an arrow in FIG.

If the seal on the peripheral surface 33a of the base end 3 is defective, the air or the like sent into the inspection jig 8 passes through the defective seal to the corner C. In the case of a conventional fuel injection valve having no groove on the stepped surface, the air or the like that has escaped to the corner C may escape to the outside of the O-ring when the O-ring is pressed against the stepped surface and airtightness occurs. In contrast, in the case of the fuel injection valve 1 of the present invention, air or the like escaping to the corner C passes through the gap S intersecting with the O-ring 5, whereas the seal failure may not be found. Thus, the O-ring 5 is pulled out of the O-ring 5, and a defective seal on the peripheral surface 33a of the base end 3 can be reliably found.

If the seal on the inner peripheral surface 8a of the inspection jig 8 is defective, air or the like sent into the inspection jig 8 leaks to the outside of the O-ring 5 through the defective seal. This finds a bad seal.

A seal on the peripheral surface 33a of the base end 3;
It is known that if there is no failure with any of the seals on the inner peripheral surface 8a of the inspection jig 8, leakage of air or the like does not occur and the seal of the O-ring 5 is good.

As described above, according to the fuel injection valve of the present invention, regardless of whether the O-ring is in close contact with the positioning step surface and airtightness is generated, the small-diameter portion at the base end can be accurately formed. The quality of the seal on the peripheral surface can be determined.

Although one end of the groove is opened on the peripheral surface of the large-diameter portion at the base end, communication between the corner and the outside is ensured, but one end of the groove is sufficiently positioned outside the annular stepped surface. It is not limited as long as it is close to the periphery and communication between the corner and the outside is ensured.

[Brief description of the drawings]

FIG. 1 is a side view of a fuel injection valve of the present invention.

FIG. 2 is a cross-sectional view of the fuel injection valve taken along line AA in FIG.

FIG. 3 is a partial cross-sectional side view of a fuel injection valve of the present invention and a jig for airtightness inspection connected thereto.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel injection valve 1 b fuel supply port (fuel inlet) 2 tip 3 base end 31 step 31 a step 32 groove 33 small diameter section 33 a peripheral surface 34 large diameter section 34 a peripheral surface 5 O-ring 7 outlet of fuel supply pipe End 8 Inspection jig

Claims (2)

[Claims] 1. A base end having a fuel inlet formed therein is fitted into an outlet end of a fuel supply pipe, and an O-ring provided on an outer periphery of the base end seals the airtightness between the base end and the outlet end. A fuel injection valve having an O-ring positioning step formed on the peripheral surface of the base end portion, wherein the O-ring supporting step is provided on the step surface of the step supporting the O-ring. A fuel injection valve characterized in that a groove is provided in a direction intersecting with the fuel injection valve. 2. The fuel injection valve according to claim 1, wherein one end of the groove is opened in a peripheral surface of the base end.