JPS6316589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical fuel pump, and more particularly to a mechanical fuel pump that is improved so that there is no fear of fuel leakage and the installation state of the diaphragm can be visually confirmed during assembly. Regarding.

Conventional mechanical fuel pumps had an upper body and a lower body made of die-cast metal, but recently the upper body, or outer casing, has been made of sheet metal in order to reduce material and processing costs and to reduce weight. Mechanical fuel pumps are widely used.

For example, there is a known mechanical fuel pump having a structure as shown in FIG. 1, but this known fuel pump still has some problems that need to be improved.

The structure and problems of a known mechanical fuel pump will be explained below with reference to FIG.

In the figure, 1 is a die-cast lower body, and a rocker arm 2, a pull rod 3, a diaphragm spring, etc. are accommodated in the lower body 1. The lower body 1 has a flange 4 at its upper end, and the outer peripheral edge of a diaphragm 5 is supported on the flange 4. The center of the diaphragm 5 is connected to the pull rod 3, and the space below the diaphragm 5 forms a lower pump chamber. A sheet metal separator 7 constituting the upper pump chamber 6 is disposed above the diaphragm 5, and the separator 7 has a flange portion 8 at its lower end.
It is overlaid on the outer periphery of the . Separator 7
An outer casing 9 made of sheet metal is disposed above, and the outer casing 9 press-fits the flange portion 8 of the separator 7 and the outer peripheral edge of the diaphragm 5 onto the flange 4 of the lower body 1 at its lower end, and The lower end portion is also caulked to the flange 4 of the lower body 1. The inner space of the outer casing 9 is divided into two parts, and a suction chamber 10 and a discharge chamber 11 are formed above the separator 7. The suction chamber 10 has a suction pipe 12.
is attached, and a discharge chamber 13 is inserted into the discharge chamber 11. The separator 7 has a suction valve 14 that allows communication between the suction chamber 10 and the upper pump chamber 6.
A discharge valve 15 is provided which allows communication between the discharge chamber 11 and the upper pump chamber 6.

When assembling a known mechanical fuel pump having the above structure, the diaphragm 5 and the separator 7 are placed on the flange 4 of the lower body 1, and then the outer casing 9 is pressed against the lower end of the outer casing 9. However, since the diaphragm cannot be seen from the outside after assembly is completed, according to such a known structure, it is necessary to visually check whether the diaphragm 5 is crimped in the correct state. There was a problem that it was not possible. In the above structure, the outer diameter of the diaphragm before assembly is designed to be larger than the outer diameter of the flange 4 of the lower body 1 in order to form the curved portion 5a in the diaphragm 5 after assembly. If you are not careful enough to prevent the outer periphery of the diaphragm 5 from protruding to the outside of the flange 4 when covering it over the flange 4, the outer periphery of the diaphragm 5 may be rolled up to the outside of the flange 4 by the lower end of the outer casing 9. If you continue to assemble without noticing such a condition, the airtightness between the flange 4 of the lower body 1, diaphragm 5, and separator 7 will deteriorate, resulting in the production of defective products. There was a possibility that it would go away. Furthermore, the above structure has the problem that even if the outer circumferential edge of the diaphragm 5 curls up to the outside of the flange 4, it cannot be visually confirmed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved mechanical fuel pump that solves the above-mentioned problems and allows the installation state of the diaphragm to be visually checked and the probability of producing defective products to be greatly reduced. It is.

Next, embodiments of the present invention will be described with reference to FIGS. 2 to 4.

In the fuel pump improved by the present invention,
As shown in FIGS. 2 and 3, the separator 7
A folded part 8a that is bent radially inward is connected to the outer circumferential edge of the flange part 8, and the outer circumferential edge of the flange 5 is held between the flange part 8 and the folded part 8a.

Therefore, when assembling, first integrate the diaphragm assembly (diaphragm 5 and pull rod 3) and separator 7 as shown in FIG.
Place the separator 7 on the flange 4 of the lower body 1, insert the pull rod 3 into the lower body 1, and press the flange 8 of the separator 7 with the outer casing 9. It is tightened.

By allowing the separator 7 to support the diaphragm 5 in this manner, it is possible to visually confirm the gripping state of the outer peripheral edge of the diaphragm 5, and the diaphragm 5 can always be installed correctly, and moreover, it is possible to avoid incorrect installation. will not occur.
Moreover, the outer peripheral edge of the diaphragm 5 is formed by a separator 7.
and the outer casing 9, and the small gaps along the upper and lower surfaces of the outer periphery of the diaphragm 5 open toward the center of the diaphragm 5, so that the airtightness is better than that of a conventional fuel pump. It is very high compared to

FIG. 5 shows a modified embodiment of the present invention. In this embodiment, in order to improve workability during assembly, a notch step 4a is provided on the flange 4 of the lower body 1 along the outer periphery. The folded portion 8a of the separator 7 is configured to fit into the cutout step portion 4a. According to this configuration, the separator 7 can be easily positioned on the lower body 1, and there is no worry that the separator 7 will move on the lower body 1 when the outer casing 9 is caulked from above the separator 7, and the positioning of the separator 7 with respect to the lower body 1 can be ensured. In addition, the outer casing 9 can be attached accurately and quickly.

As described above, according to the present invention, the diaphragm can be installed accurately, the installation state can be visually confirmed, and effects such as improved workability during assembly and improved airtightness can be expected. , an improved mechanical fuel pump is provided.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a conventional mechanical fuel pump, FIG. 2 is a vertical cross-sectional view of a mechanical fuel pump improved according to the present invention, and FIG. 3 is a vertical cross-sectional view of a conventional mechanical fuel pump.
FIG. 4 is an assembled view of a part of the pump of FIG. 2, and FIG. 5 is a view similar to FIG. 3, showing another embodiment of the present invention. 1: lower body, 2: rotsker arm, 3:
Pull rod, 4: (lower body) flange,
5: diaphragm, 6: upper pump chamber,
7: separator, 8: flange part (of separator), 8a: folded part (of flange part 8), 9: outer casing, 10: suction chamber, 11: discharge chamber, 12: suction pipe, 13: discharge pipe, 14 : Suction valve, 15: Discharge valve.

Claims (1)

[Scope of Claims] 1. A lower body made of cast iron having a flange at its upper end and housing a rocker arm, a pull rod, and a diaphragm spring therein, an outer peripheral edge supported on the flange, and a central portion connected to the pull rod. a diaphragm; a separator made of sheet metal having a flange portion at its lower end disposed above the diaphragm and pressed against the outer peripheral edge of the diaphragm and forming a pump chamber above the diaphragm; a sheet metal disposed at the lower end of which the flange portion of the separator and the outer peripheral edge portion of the diaphragm are caulked onto the flange of the lower body, and which constitutes a suction chamber and a discharge chamber above the separator; In a mechanical fuel pump having an outer casing made of integrating the separator and the diaphragm by sandwiching the outer peripheral edge of the diaphragm;
The mechanical fuel pump is further characterized in that the flange portion and the folded portion of the separator are configured to be caulked onto the flange of the lower body by a lower end portion of the outer casing.