JP2003083199A - Pulsation damper for fuel delivery pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulsation damper for a fuel delivery pipe having superior assembling and mounting workability with a simple structure. SOLUTION: This pulsation damper 30 comprises a housing communicated with a pipe body 20, an elastic sealed hollow member 25 is mounted in the housing, and a volume of the hollow member 26 is increased and decreased when the fuel pressure in the fuel delivery pipe 10 pulsates. The shape of the hollow member 26 is preferably spherical, and the hollow member 26 may have heatproof resin foam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulsation damper for absorbing pulsation generated when fuel is supplied by a fuel injection valve of an automobile engine, for example.

[0002]

2. Description of the Related Art Generally, a fuel injection type automobile engine has a plurality of fuel injection valves, and in order to supply fuel to these fuel injection valves, a plurality of cylinders that receive an introduction shaft of the fuel injection valves. A fuel delivery pipe having a socket is used.

In the fuel delivery pipe, fuel pressure pulsation occurs as fuel is injected from the fuel injection valve. In order to damp this pulsation, a pulsation damper is generally attached to the fuel delivery pipe.

A conventional pulsation damper is generally provided with a diaphragm arranged in a metal case and a spring for pressing the diaphragm, and is connected to a fuel delivery pipe through a pipe or the like connected to the case. Things were used.

For example, Japanese Unexamined Patent Publication No. 2000-104636 includes a diaphragm which is divided into a fuel chamber and an air chamber which communicates with the atmosphere. The diaphragm is supported by a spring mounted in the air chamber, and is outside the fuel chamber. A pulsation damper having a connection flange is disclosed.

This pulsation damper is bolted to a mounting portion having a flange provided at one end of the fuel delivery pipe, a socket tube is fixed to the fuel chamber of the pulsation damper, and a fuel supply hose is inserted into this socket tube. It is designed to be fixed.

[0007]

However, the above-mentioned conventional pulsation damper is difficult to assemble because it is composed of many parts such as a diaphragm, a spring and a case.
There was also a problem that it took time to attach the fuel delivery pipe.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel delivery pipe having a pulsation damper which has a simpler structure and is easy to assemble and install.

[0009]

In order to achieve the above object, the first aspect of the present invention is to provide a housing communicating with a fuel delivery pipe, wherein an elastic sealed hollow body is provided in the housing. A pulsation damper for a fuel delivery pipe, wherein the volume of the hollow body is increased or decreased when the fuel pressure in the fuel delivery pipe pulsates.

According to the above invention, the elasticity of the gas inside the sealed hollow body is utilized to increase or decrease the volume of the hollow body accommodated in the housing in accordance with the pulsation, so that the pulsation of the fuel pressure is effectively suppressed. Can be attenuated. Further, since the pulsation damper is composed of only the housing and the hollow body, the number of parts is small, the cost can be reduced, the structure is simplified, and the assembling and mounting operations are facilitated.

A second aspect of the present invention provides the pulsation damper for a fuel delivery pipe according to the first aspect, wherein the hollow body has a spherical shape.

According to the above invention, since the hollow body has a spherical shape, when the pressure due to pulsation is applied, the stress is dispersed without being concentrated at a specific location. Therefore, the hollow body is less consumed and the life of the parts can be extended.

A third aspect of the present invention provides the pulsation damper for a fuel delivery pipe according to the first or second aspect, wherein the hollow body has a heat-resistant resin foam.

According to the above invention, the hollow body can be easily manufactured by using the resin foam as the hollow body.
Further, since the hollow body can be manufactured according to the shape of the housing, it can be easily mounted in the housing.

A fourth aspect of the present invention provides the pulsation damper for a fuel delivery pipe according to any one of the first to third aspects, wherein at least one annular groove is provided on the surface of the hollow body. To do.

According to the above invention, among the surfaces of the hollow body,
Since the portion surrounded by the annular groove is easily bent, the volume of the hollow body is easily increased or decreased, and the response and reliability of the increase or decrease in volume with respect to pulsation can be improved.

[0017]

1 to 3 show one embodiment of a pulsation damper for a fuel delivery pipe according to the present invention. FIG. 1 is an exploded perspective view of a pulsation damper for a fuel delivery pipe of the present invention, FIG. 2 is a view showing the pulsation damper, where (a) is a front view, (b) is a side view, and (c) is. 3 is a plan view and FIG. 3 is a view showing a housing portion of the pulsation damper, where (a) is a cross-sectional view when the fuel pressure is low, and (b) is a cross-sectional view when the fuel pressure is high.

As shown in FIGS. 1 and 2, the fuel delivery pipe 10 has a pipe body 20 having at one end a nipple 21 to which a fuel supply pipe (not shown) is connected.
The pipe main body 20 is made of a synthetic resin integrally molded pipe, and has cylindrical sockets 22 connected to a fuel injection valve of an engine (not shown) at three positions in the longitudinal direction. Further, two tongue pieces 24 each having a mounting hole 23 are formed between the three sockets 22 and are fixed to a predetermined position of the engine.

At the end of the pipe body 20 on the side opposite to the nipple 21, the inner circumference of the end of the pipe body 20 of the fuel delivery pipe is expanded to form a cylindrical shape, and that portion serves as a pulsation damper case 25. Has become. And
A cap 27 is welded to an end of the case 25 to form a housing 28, and the hollow body 26 is provided inside the housing 28.
Is accommodated to form the pulsation damper 30.

In the present invention, the pipe main body 20 and the housing 28 communicating with the pipe main body 20 may be integrally formed as shown in FIG. 1, and the pipe main body 20 and the housing 28 are separate bodies. It may be connected by a rubber tube or the like. The material of the pipe body 20 is not particularly limited to synthetic resin and may be metal or the like. The housing 28 may be provided at a position other than the end portion of the pipe body 20, or may be provided at the central portion of the pipe body 20 or the like.

As shown in FIG. 3, the hollow body 26 has a spherical shape, is housed so as to abut the inner wall of the housing 28, and is attached to the pipe body 20 with a part of the spherical body protruding. Has been done.

The material forming the hollow body 26 is not particularly limited as long as it has elasticity when the hollow body is formed.
Examples thereof include rubber, elastomer and resin. Particularly preferable materials from the viewpoint of heat resistance and gasoline resistance are fluorine-based rubbers as rubber materials, and nylon resins, polypropylene resins, polyacetal resins and polyphenyl sulfide resins as resins.

The shape of the hollow body 26 is not particularly limited, and examples thereof include a spherical shape, a cylindrical shape, a hexagonal shape, a spindle shape, and the like. However, since the stress due to pulsation can be dispersed throughout the hollow body, It is preferably shaped.

The size of the hollow body 26 is appropriately selected so as to abut the inner wall of the housing 25.
Is spherical, the diameter is preferably 20 to 30 mm. The thickness of the coating film forming the hollow body 26 can be appropriately selected depending on the elasticity of the material and the fuel permeability, but is preferably in the range of 1 to 5 mm.

The hollow body 26 is hermetically sealed with gas enclosed therein. The enclosed gas may be air or a gas other than air such as nitrogen. Further, the pressure of the enclosed gas is not particularly limited, and it can be enclosed under normal pressure or in a pressurized state.

Next, the operation of the pulsation damper for the fuel delivery pipe will be described. The fuel delivery pipe 10 has a fuel supply pipe (not shown) connected to the nipple 21, and a socket 22 connected to a fuel injection valve of an engine (not shown). And fuel each socket 2
2 to the fuel injection valve.

At this time, pulsation may occur in the fuel pressure in the fuel delivery pipe 10 due to the opening and closing of the fuel injection valve. However, as shown in FIG. 3A, when the fuel pressure in the fuel delivery pipe 10 is not large, the surface of the hollow body 26 in the pulsation damper 30 that projects into the pipe body 20 is the end surface 20 a of the pipe body 20. When the fuel pressure increases, the hollow body 26 is pushed in by the pressure due to the pulsation and its volume is reduced, and the hollow body 26 is deformed into an oval shape. Attenuate.

As described above, in this embodiment, the housing 2 that communicates with the pipe body 20 of the fuel delivery pipe 10.
Since the pulsation damper 30 can be composed of only the hollow body 26 and the hollow body 26, the pulsation damper 30 can be easily assembled and attached, and the number of parts can be reduced to reduce the cost.

4 and 5 show another embodiment of the pulsation damper for the fuel delivery pipe of the present invention. FIG. 4 is an exploded perspective view of the pulsation damper for the fuel delivery pipe, and FIG. 5 is a view showing the pulsation damper. In each of the embodiments described below,
The same reference numerals will be given to the substantially same parts as those in the above-mentioned embodiment, and the description thereof will be omitted.

The fuel delivery pipe 11 basically has the same structure as the embodiment of FIG. 1, but the structure of the pulsation damper 30a is different. That is, in the pulsation damper 30a, a hollow cylindrical body 26a is used instead of the hollow hollow body 26.
The difference from the first embodiment is that a resin foam 29 is provided inside a. Here, as the material of the resin foam 29, any resin foam having heat resistance may be used, and polyolefins such as nylon and polypropylene can be exemplified.

The method for molding the hollow body 26a is not particularly limited. For example, the resin foam 29 is molded in advance into a predetermined shape, in this embodiment a cylindrical shape, and then a film 29a for sealing is provided on the surface. it can.

As shown in FIG. 5, in the hollow body 26a, the circumferential surface of the hollow body 26a abuts on the inner peripheral surface of the case 25, and the expanded diameter step portion 25a of the case 25 and the inner surface of the cap 27 are hollow. Both end faces of the body 26a are inserted in contact with each other. As a result, when the fuel pressure is low, the hollow body 26
The a is arranged in a state of being spread inside the housing 28. When the fuel pressure is applied, the volume of the resin foam 29 in the hollow body 26a is reduced due to the elasticity of the bubbles, and the hollow body 26a is deformed to cause pulsation as in the first embodiment. Attenuate.

According to the pulsation damper 30a, since the resin foam is used as the hollow body, it is easy to manufacture the hollow body having the same shape. Further, since it is possible to manufacture a hollow body matching the shape of the housing 28, the case 2
5 can be easily installed.

6 and 7 show another embodiment of the pulsation damper for the fuel delivery pipe according to the present invention. FIG. 6 shows a hollow body to be inserted into the pulsation damper, where (a) is a side view and (b) is a front view.
(C) is a side sectional view and (d) is a perspective view. Further, FIG. 7 is a diagram showing the pulsation damper, which includes (a)
FIG. 4B is a cross-sectional view in the state where the fuel pressure is low, and FIG. 9B is a cross-sectional view in the state where the fuel pressure is high.

The pulsation damper 30b has a hollow body 40 formed by joining a pair of plate-shaped thin plates 41 and 42 made of metal or the like. Each thin plate 4
1 and 42 have bulging parts 41a and 42a in the center, and the periphery forms flange parts 41b and 42b. Furthermore, the annular grooves 41c and 42c are formed around the bulging portions 41a and 42a.
Are formed. Then, the bulging portions 41a, 42a are directed outward, the flange portions 41b, 42b are abutted, and the flange portions 41a, 42b are joined by means such as welding or adhesion, whereby the hollow body 40 is formed.

In this hollow body 40, the flange portion 41b is brought into contact with the enlarged diameter step portion 25a of the case 25 formed at the end portion of the pipe body 20 of the fuel delivery pipe, and the cap 27 is formed.
The spinning portion 42b is brought into contact with and housed. And
In the state where the fuel pressure is small, as shown in FIG. 7A, the other bulging portion 41b is held in a state of protruding toward the pipe body 20 side.

When the fuel pressure increases due to the pulsation, as shown in FIG. 7B, the bulging portions 41a, 42a surrounded by the annular grooves 41c, 42c of the hollow body 40.
However, when it is pushed into the inside, it becomes a flat shape as shown in FIG. 7B, and absorbs the pressure fluctuation due to pulsation. In this case, the annular grooves 41c, 42c cause the bulges 41a, 4
Since 2a is easily deformed, a reliable volume change is possible, and the responsiveness and reliability to pressure fluctuation due to pulsation are improved.

[0038]

As described above, according to the present invention,
By increasing or decreasing the volume of the hollow body housed in the housing, the pulsation of the fuel pressure can be received by the piston and effectively damped. Moreover, since the pulsation damper is composed of only the housing and the hollow body, the number of parts is small, the cost can be reduced, and the structure is simplified.
Assembly and installation work is also easy.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a pulsation damper for a fuel delivery pipe of the present invention.

FIG. 2 is a view showing the pulsation damper,
(A) is a front view, (b) is a side view, and (c) is a plan view.

3A and 3B are cross-sectional views showing a housing portion of the pulsation damper, in which FIG. 3A is a cross-sectional view when the fuel pressure is low, and FIG. 3B is a cross-sectional view when the fuel pressure is high.

FIG. 4 is an exploded perspective view showing another embodiment of the pulsation damper for a fuel delivery pipe of the present invention.

FIG. 5 is a cross-sectional view showing a housing portion of the pulsation damper in a state where fuel pressure is low.

FIG. 6 is a view showing a hollow body used in still another embodiment of the pulsation damper for a fuel delivery pipe of the present invention, (a) is a side view, (b) is a front view, and (c).
Is a side sectional view, and (d) is a perspective view of a hollow body.

7A and 7B are cross-sectional views showing a housing portion of the pulsation damper, in which FIG. 7A is a cross-sectional view when the fuel pressure is low, and FIG. 7B is a cross-sectional view when the fuel pressure is high.

[Explanation of symbols]

10, 11 Fuel delivery pipe 20 Pipe body 21 nipples 22 socket 25 cases 26, 26a, 40 Hollow body 27 caps 28 housing 29 Resin foam 30, 30a, 30b Pulsation damper 41, 42 thin plate 41a, 42a bulging portion 41b, 42b Flange part 41c, 42c annular groove

Claims (4)

[Claims] 1. A housing which communicates with a fuel delivery pipe, wherein a sealed hollow body having elasticity is provided in the housing, and when the fuel pressure in the fuel delivery pipe pulsates, the hollow body is provided. A pulsation damper for a fuel delivery pipe, which is characterized by increasing and decreasing the volume of. 2. The pulsation damper for a fuel delivery pipe according to claim 1, wherein the hollow body has a spherical shape. 3. The pulsation damper for a fuel delivery pipe according to claim 1, wherein the hollow body has a heat-resistant resin foam. 4. The method according to claim 1, wherein at least one annular groove is provided on the surface of the hollow body.
Pulsation damper for the fuel delivery pipe described in section 3.