JPH0135035Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a diaphragm-type fuel damper used for smoothing pulsation of fuel discharged from a fuel pump in a fuel supply system of an internal combustion engine.

<Prior Art> As a conventional fuel damper, there is one shown in FIG. 3, for example (see Utility Model Application No. 58-79052, etc.).

The diaphragm type fuel damper shown in Figure 3 is
A resin casing 1 whose internal space 7 is communicated with a fuel supply passage 8, a metal cap 2 fitted over the casing 1, and a metal cap 2 which is sandwiched between the casing 1 and the cap 2 to It includes a rubber diaphragm 3 that closes a space 7, an armature 4 attached to the center of the diaphragm 3, and a coil spring 5 that elastically biases the armature 4 from the cap 2 side to the casing 1 side. As the material of the casing 1, resin is used, especially when used with an in-tank fuel pump, for example, nylon resin mixed with glass fiber is used. Reference numeral 6 denotes a holder which fixes the armature 4 to the diaphragm 3 and holds the spring 5.
It is a member that receives the elastic force of.

FIG. 4 shows a portion A of FIG. 3 in an enlarged manner. As shown in the figure, in the conventional fuel damper, a groove 9 is formed along the peripheral edge of the casing 1.
A convex portion 31 formed integrally with the peripheral edge of the diaphragm 3 is fitted into the groove 9, thereby sealing the inside of the casing 1. 9a indicates a seal portion formed on the bottom surface of the groove 9. The diaphragm 3 is made by stacking two diaphragms 3a and 3b, and a convex portion 31 is integrally formed on the lower diaphragm 3a. Further, 21 indicates a caulking portion of the cap 2.

<Problems to be solved by the invention> However, in the conventional fuel damper described above, since resin is used for the casing 1, the heat resistance is poor, so the seal portion 9a may be heated and shrunk. However, due to variations in the force with which the convex portion 31 of the diaphragm 3 is tightened, there is a problem in that the sealing condition at that portion tends to be poor. In fact, when we attempted a temperature alternation test, an airtight leak occurred.

Another problem was that the seal portion 9a on the bottom surface of the groove 9 into which the convex portion 31 of the diaphragm 3 fits is easily damaged, and this also tends to cause the sealing condition of the casing 1 to become poor.

Incidentally, the solid line arrow in FIG. 3 indicates the route of airtight leakage due to the above-mentioned seal failure.

The present invention was devised to solve the above-mentioned problems, and its purpose is to solve the problems without making any major changes to the material of the casing or to the overall configuration. An object of the present invention is to provide a fuel damper that can obtain a stable and good sealing state with good reproducibility.

<Means for solving the problems> The present invention, as a means to achieve the above objectives,
A resin casing whose internal space communicates with the fuel supply path, a metal cap that fits over the casing, and a rubber diaphragm that is held between the casing and the cap and closes the space inside the casing. , an armature attached to the center of the diaphragm, and a spring that elastically biases the armature from the cap side to the casing side, and the diaphragm is fitted into a groove formed along the peripheral edge of the casing. In a fuel damper in which the inside of the casing is sealed by fitting a convex portion integrally formed on the peripheral edge, an annular metal frame member is molded along the inside of the groove, and the metal frame member is molded along the inside of the groove. The convex portion of the diaphragm is fitted inside the diaphragm.

<Function> By the above means, variations in dimensional accuracy within the groove into which the convex portion of the diaphragm fits is reduced, and as a result, the force for tightening the convex portion becomes constant,
A stable and good sealing condition can be obtained with good reproducibility. Further, since the seal portion on the bottom surface of the groove into which the convex portion is fitted is made of the metal frame member, it is difficult to be damaged, and as a result, a stable and good sealing state can be obtained with good reproducibility. Furthermore, the metal frame member can be molded simultaneously with the molding of the casing by integral molding. This makes it possible to ensure excellent suitability for mass production, which is not much different from the case where the casing is formed only from resin.

<Example> An example of the present invention will be described below based on FIG. 1.

The fuel damper, the main part of which is shown in Figure 1, is used to smooth the pulsation of fuel discharged from the fuel pump, and its basic configuration is the same as the conventional one described above. be. Therefore, the following explanation will mainly focus on the parts that are different from the conventional one.
Explanation of overlapping parts will be omitted.

In this fuel damper, an annular metal frame member 10 is molded along the inside of a groove 9 formed on the peripheral edge of a resin casing 1. The convex portion 31 of the diaphragm 3 is fitted inside this metal frame member 10. As a result, the convex portion 31 of the diaphragm 3
It is pressed against and pinched by a seal portion 10a formed on the bottom surface of the groove. Incidentally, protrusions 10b are provided on both sides of the metal frame member 10, and the outer surface is made rough to improve moldability.
In this case, moldability is further improved by forming irregularities on the outer surface of the metal frame member 10 as shown in FIG. 2, for example.

Further, in this embodiment, a groove 11 is formed along the outer peripheral edge of the casing 1. This groove 1
1, an O-ring 12 is fitted. At the same time, the peripheral edge of the cap 2 is caulked to the outside of the peripheral edge of the casing 1. The O-ring 12 is pressed between the caulked portion 21 and the outer peripheral edge of the casing 1.

Now, in the above-mentioned fuel damper, first, since the groove portion into which the convex portion 31 of the diaphragm 3 is fitted is made of metal, heat shrinkage is smaller than in the case of resin. As a result, the force for tightening the convex portion 31 becomes constant, and a stable and good sealing state can be obtained with good reproducibility.

Further, since the seal portion 10a on the bottom surface of the groove into which the convex portion 31 is fitted is made of the metal frame member 10, it is hard to be damaged.
This also makes it possible to obtain a stable and good sealing state with good reproducibility.

Furthermore, the metal frame member 10 can be molded simultaneously with the molding of the casing 1 by integral molding. This makes it possible to ensure excellent suitability for mass production, which is not much different from the case where the casing 1 is formed only of resin.

As described above, a stable and good sealing state can be obtained with good reproducibility without making any major changes to the material of the casing or without making any major changes to the overall configuration.

Furthermore, the O-ring 12 doubles the seal of the casing 1, thereby making it possible to obtain a more reliable sealing state.

<Effects of the invention> As is clear from the description of the embodiments above, the fuel damper according to the invention has improved heat resistance without making any major changes to the material of the casing or to the overall configuration. This has the effect of preventing damage to the sealing portion and achieving a stable and good sealing condition with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a fuel damper according to the present invention, showing a portion corresponding to part A in FIG. 3; FIG. 2 is a sectional view showing a modified example of a metal frame member; FIG. 3 is a cross-sectional view showing the overall structure of a fuel damper, and FIG. 4 is an enlarged cross-sectional view of an example of a conventional fuel damper, showing a portion corresponding to section A in FIG. 1... Resin casing, 2... Metal cap, 3... Diaphragm, 4... Armature,
5... Spring, 9... Groove, 10... Metal frame member,
31...Protrusion.

Claims (1)

[Scope of utility model registration request] A resin casing whose internal space communicates with the fuel supply path, a metal cap that fits over the casing, and a rubber diaphragm that is held between the casing and the cap and closes the space inside the casing. , an armature attached to the center of the diaphragm, and a spring that elastically biases the armature from the cap side to the casing side, and the diaphragm is fitted into a groove formed along the peripheral edge of the casing. In a fuel damper in which the inside of the casing is sealed by fitting a convex portion integrally formed on the peripheral edge, an annular metal frame member is molded along the inside of the groove, and the metal frame member is molded along the inside of the groove. A fuel damper characterized in that a convex portion of the diaphragm is fitted inside the diaphragm.