JPH1030514A - Check valve installing structure for diaphragm fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the depth of a pump acting chamber, and form a diaphragm fuel pump in a compact size by inserting each cylindrical projection formed integratedly with the bulk head of a pump cabinet made of thermoplastic resin into opening holes arranged on intake/discharging side check valves, caulking the end part of the projection by means of heat, and fixing the check valves to a bulk head. SOLUTION: Each cylindrical projection 14 which is enabled to deforme by heating and push-pressing is formed on the bulk head 4 of a pump cabinet 1 formed of thermoplastic resin integratedly with the bulk head 4. After the projections 14 are inserted into inserting hole arranged on intake/discharging side check valves 5, 7, end surfaces of the projection 14 are heated and push- pressed by a heated trowel 15, they are caulked by heat, and then the check valves 5, 7 are fixed to a bulk head 4. The thickness of the end part which is heating-caulked and whose diameter is enlarged in the projection 14 is formed lower than the height of the head of a screw member or the head of a gromet. It is thus possible to make reduce the depth (d) of the pump operating chamber 9, and form a diaphragm fuel pump in a compact size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a structure for attaching a check valve to a suction passage and a discharge passage of a pump working chamber in a membrane fuel pump in which a pumping operation is performed by bending vibration of a flexible membrane.

[0002]

2. Description of the Related Art FIG.
Taking the membrane fuel pump proposed with 936 as an example,
BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the example of the conventional structure of the membrane fuel pump to which this application is applied, 1 is a pump housing | casing, 2 is a pump housing | casing 1
The cover 3 disposed on one end face of the pump housing 3 is a flexible membrane sandwiched between the pump housing 1 and the cover 2, and the partition wall 4 is formed between both end faces of the pump housing 1. In the partition 4, a suction passage 6 provided with a suction-side check valve 5 and a discharge passage 8 provided with a discharge-side check valve 7 are opened, and the flexible membrane 3 and the partition 4 are opened. A pump action chamber 9 in which a pump action is performed by the bending vibration of the flexible film body 3 is formed. FIG.
Are not intended to limit the scope of application of the present application, and will not be described.

In the membrane fuel pump shown in FIG. 4, both the suction-side check valve 5 and the discharge-side check valve 7 are made of a circular resin film, and a through hole formed in the center of the resin film. A grommet 10 made of a resilient rubber material is inserted into and fixed to the through hole formed in the partition wall 4 of the pump housing, and a screw member is screwed into the partition wall 4 of the pump housing 1. Some are fixed (see Japanese Utility Model Laid-Open No. 61-88084). In FIG. 5, reference numeral 4 denotes a partition wall of the pump housing 1,
Or 7 is a suction-side check valve or discharge-side check valve, 6 or 8 is a suction passage or discharge passage, and 11 is a screw member screwed into the partition wall 4. 6, the same reference numerals as those in FIG. 5 indicate the same parts as those in FIG. 5, and reference numeral 10 denotes a grommet.

In the configuration shown in FIG. 5 in which the screw member 11 is screwed into the partition wall 4 to fix the suction-side check valve 5 or the discharge-side check valve 7, if a cheap screw member is used, rust is reduced. The use of a stainless steel material, for example, a SUS material, leads to an increase in cost, and the use of a screw member generates chips when the screw member is screwed into the partition wall 4 and causes vibration of the engine. This may cause loosening of the screw member. As shown in FIG. 6, if a grommet is used, there is no loosening due to rust, chips and vibration, but it is expensive.

In a membrane fuel pump, the pump action chamber 9
Is smaller, that is, the shallower the depth of the pump action chamber 9 shown in FIG. For example, when the engine is started by recoil, the air or fuel vapor existing in the pump action chamber 9 is quickly eliminated with a small number of recoils, and the fuel is quickly supplied to the engine to facilitate the start of the engine. Become. However, on the other hand, when the flexible membrane 3 comes into contact with the head of the screw member 11 fixing the suction-side check valve 5 or the head of the grommet 10 during the flexural oscillation, the flexural oscillation of the flexible membrane 3 occurs. And the pump action is impaired, the depth d of the pump action chamber 9 (FIG. 4) depends on the head height h of the screw member 11 or the head height h of the grommet 10 (FIGS. 5 and 6). Be constrained. The height h of the head of the ready-made screw member 11 is fixed, and the grommet 10
The height h of the head cannot be unnecessarily reduced because it requires a strength to tighten the suction-side check valve 5 or the discharge-side check valve 7 to the partition wall 4. If the depth d of the pump action chamber 9 can be made shallow, not only the startability of the engine can be improved, but also the height of the pump housing 1 can be reduced, which is effective for making the membrane fuel pump compact.

[0006]

The depth of the pump action chamber 9 is reduced by improving the mounting structure of the suction check valve 5 or the discharge check valve 7 to the suction passage 6 or the discharge passage 8, respectively. It is an object of the present invention to improve the startability of the engine and to make the membrane fuel pump compact and to reduce the cost of the membrane fuel pump.

[0007]

A flexible membrane 3 is disposed between one end face of the pump housing 1 and a lid 2 on the end face side thereof. A suction passage 6 provided with a suction-side check valve 5 and a discharge passage 8 provided with a discharge-side check valve 7 are opened in a partition wall 4 formed between the surfaces to open the flexible membrane 3 and A membrane type fuel pump in which a pump action chamber 9 in which a pump action is performed by bending vibration of the flexible membrane body 3 is formed between the partition wall 4 and the pump housing 1, which is formed of a thermoplastic resin. A columnar projection is formed integrally with the partition wall, and an insertion hole of the columnar projection is formed in the suction-side check valve 5 and the discharge-side check valve 7. After the columnar projection is inserted through the columnar projection, the suction-side check valve 5 or the discharge-side non-return valve 7 is moved by heat caulking at an end of the columnar projection. The fixed structure to the wall 4.

[0008]

When the pump housing 1 is made of a thermoplastic resin, the end of the columnar projection formed on the partition wall 4 can be deformed by heating and pressing. After inserting the columnar projection into the insertion hole provided in the discharge side check valve 7, the end face of the columnar projection is heated and pressed, and the suction side check valve 5 and the discharge side check valve 7 are inserted into the partition wall 4 by heat caulking. Can be fixed. The thickness of the large-diameter end portion of the columnar protrusion that is thermally caulked can be made smaller than the height h of the head of the screw member 11 or the head of the grommet 10. The depth d can be reduced, and the height H of the pump housing 1 is also reduced, so that the membrane fuel pump can be made compact. If the pump housing 1 is formed of a thermosetting resin or an aluminum or zinc alloy, even if the columnar projections are formed, the end portion cannot be thermally caulked.

A component for attaching the suction-side check valve 5 and the discharge-side check valve 7 to the partition wall 4 of the pump housing 1 becomes unnecessary, and the man-hour for heat caulking is smaller than the man-hour for mounting the screw member 11 or the grommet 10. Thus, the cost of the membrane fuel pump is reduced.

[0010]

FIG. 1 is a sectional view of an example of a membrane fuel pump to which a check valve mounting structure according to the present invention is applied.
FIG. 1 shows an example of a pulsating pressure type membrane fuel pump in which a flexible membrane member 3 bends and vibrates by a pulsating pressure generated in a crankcase or an intake pipe of an engine to perform a pumping operation. Is not limited to a pulse pressure type membrane fuel pump, but is also applied to a membrane type fuel pump that flexibly vibrates the flexible membrane 3 mechanically, such as a lever type or a push rod type. is there. In FIG. 1, reference numerals 1 to 9 denote the same parts as those shown in FIG.
Reference numeral 2 denotes an end portion of a columnar projection (described later) formed integrally with the partition wall 4 of the pump housing 1 and having a large diameter due to thermal caulking. 13 is a fuel inlet.

The end portion 1 having a large diameter due to the heat caulking.
The height d of the pump action chamber 9 can be reduced by the fact that the height of the pump action chamber 9 is low and that there is nothing protruding on the pump action chamber 9 side. And the engine can be easily started.
Height is reduced, which is effective in reducing the size of the membrane fuel pump.

FIG. 2 shows a state before thermal caulking is performed.
14 is a partially enlarged view of the columnar projection 14 formed on the partition 4 of the pump housing 1 integrally with the partition 4, and 15 is the columnar projection 1.
With a heated iron for performing thermal caulking at the end of No. 4, the end face of the columnar projection 14 is pressed in the direction of the arrow to perform thermal caulking. In FIG. 2, 5 or 7 is a suction-side check valve or a discharge-side check valve, respectively, and 6 or 8 is a suction passage or a discharge passage, respectively, as in the case of FIG. 1 or FIG.

1 and 2, the central portion of the suction-side check valve 5 or the discharge-side check valve 7 made of a circular resin film is thermally caulked by a columnar projection 14 formed on the partition wall 4 of the pump housing 1. Although an example of attachment is shown, in the present invention, a long suction-side check valve 5 or a discharge-side check valve 7 that opens and closes a suction passage 6 or a discharge passage 8 formed of one through hole is disposed at a center in a longitudinal direction. The invention is also applied to a so-called cantilever check valve which is eccentrically fixed on a line. In FIG. 3, 5 or 7 is a long suction-side check valve or discharge-side check valve, 6 or 8 is a suction passage or a discharge passage, and 12 is a partition wall 4.
This is the end of the columnar projection 14 after thermal caulking. When the so-called cantilever check valve fixed at the eccentric position in the longitudinal direction is turned around the fixed position, the suction passage 6 or the discharge passage 8 cannot be closed. The check valve is provided with an opening 17, and the engagement between the projection 16 and the opening 17 prevents turning. The cantilevered check valve is made of a resin film or a sheet of elastic metal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a membrane fuel pump to which a check valve mounting structure for a membrane fuel pump according to the present invention is applied.

FIG. 2 is an enlarged view showing a structural example of the present invention in which a check valve is fixed at a central portion of the check valve.

FIG. 3 is an enlarged view showing a structural example of the present invention for fixing a check valve at an eccentric position of the check valve.

FIG. 4 is a view showing an example of a conventional membrane fuel pump having a check valve mounting structure.

FIG. 5 is a partially enlarged view showing a conventional check valve mounting structure using a screw member.

FIG. 6 is a partially enlarged view showing a conventional check valve mounting structure using a grommet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump housing 2 Lid 3 Flexible film body 4 Pump housing partition wall 5 Suction-side check valve 6 Suction passage 7 Discharge-side check valve 8 Discharge passage 9 Pump working chamber 10 Grommet 11 Screw member 12 Formed on partition wall End after heat crimping of the formed columnar projection 13 Fuel inlet 14 Columnar projection 15 Heated trowel 16 Other projection 17 Opening through which other projection is inserted

Claims (1)

[Claims] A flexible membrane (3) sandwiched between one end face of a pump housing (1) and a lid (2) on the end face side.
And a suction passage (6) provided with a suction-side check valve (5) in a partition (4) formed between both end faces of the pump housing (1) and a discharge-side check valve (7). The discharge passage (8) provided is opened, and a pump action is performed between the flexible film body (3) and the partition (4) by bending vibration of the flexible film body (3). In a membrane fuel pump having a pump working chamber (9) formed therein, wherein the pump housing (1) is formed of a thermoplastic resin, the partition wall (4) has a columnar projection (14). The columnar projection (14) is formed integrally with the partition (4), and the suction-side check valve (5) and the discharge-side check valve (7) are provided with insertion holes for the columnar projections (14). After the insertion of the check valve (14), the suction-side check valve (5) or the discharge-side check valve (7) is moved to the partition wall by thermal caulking at the end of the columnar projection (14). Check valve mounting structure of the membrane fuel pump, characterized in that fixed to 4).