JPH09217662A - Membrane fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form each rib in an '0' ring shape at the outer periphery of each flexible membrane member, thereby hold each flexible membrane member, provide each groove for compressing and housing the rib at the outer periphery of each flexible membrane for the surfaces of a pump casing and a lid body, both of which are made of resinous material, deposit the surfaces of the casing and the lid body at the outer periphery of each groove, and thereby eliminate a need for each gasket. SOLUTION: A rib 2-1 in an '0' ring shape is formed at both surfaces of the outer periphery of a first flexible membrane member 2 partitioning a pulse pressure chamber 8 and a pumping chamber 9, a rib 5-1 in an '0' ring shape is formed at both surfaces of the outer periphery of a second flexible membrane member 5 so as to allow a fuel suction and a fuel delivery chamber 10 and 11 to be partitioned, and a rib 5-2 in an '0' ring shape is formed at both surfaces of a portion partitioning an air chamber 12 corresponding to the aforesaid chambers. Grooves 1-1, 4-1, 1-2, 3, 6-1 and 2 for compressing and housing the ribs 2-1, 5-1 and 2 of the first and second flexible membrane members 2 and 5, are formed in the surfaces of the pump casing 1 and the first and second lid bodies 4 and 6, which are made of resinous material, and hold the first and second flexible membrane members 2 and 5. Yet, the pump casing 1 is deposited with the first and second lid bodies 4 and 6 at contact surfaces 19 and 20 at the outer periphery of each groove.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane fuel pump, in which a pump casing for holding a flexible membrane member and a lid are made of resin, and the pump casing and the lid are welded to each other. Concerning

[0002]

2. Description of the Related Art A pulsating pressure type membrane fuel pump in which fuel is pumped by pulsating pressure generated in an engine crankcase or an intake pipe is taken as an example, and a conventional membrane fuel pump structure is shown in FIG. Will be explained. In FIG. 10, reference numeral 1 is a pump housing, 2 is a first flexible membrane member, 3 is an annular gasket, 4 is a first lid, and 5 is a second.
Of the flexible membrane member, 3a is a gasket, 6 is a second lid, and the first lid 4 has the first flexible membrane member 2 and the annular gasket 3 interposed therebetween, and The second lid 6 is fastened to both end surfaces of the pump casing 1 by the through screw member 7 via the second flexible membrane member 5 and the gasket 3a. The structure shown in FIG. 10 is a structure in which the first flexible film member 2 and the second flexible film member 5 are rubber films containing a base cloth, but when a resin film is used, The annular gasket 3 is also provided between the pump casing 1 and the first flexible membrane member 2.
However, the gasket 3a is also held between the pump housing 1 and the second flexible membrane member 5 (details of the reason are omitted).

A pulse pressure chamber 8 is provided between the first flexible membrane member 2 and the first lid body 4, and the pump casing 1 and the first flexible membrane member 2 are connected to each other. A pump action chamber 9 is formed between them, and a fuel suction chamber 10 and a fuel discharge chamber 11 are formed between the pump housing 1 and the second flexible membrane member 5, thereby providing a second flexibility. Air chambers 12 corresponding to the fuel suction chamber 10 and the fuel discharge chamber 11 are formed between the membrane member 5 and the second lid 6.

The pump action chamber 9 and the fuel suction chamber 10 communicate with each other through a fuel passage 15 in which a suction valve 13 is arranged, and the pump action chamber 9 and the fuel discharge chamber 11 communicate with each other through a fuel passage 15 in which a discharge valve 14 is arranged so as to suck the fuel. The valve 13 and the discharge valve 14 are attached to the pump housing 1 by a grommet 16.
In FIG. 10, the passage for introducing the pulsating pressure generated by the engine into the pulse pressure chamber 8, the fuel inflow hole for introducing the fuel into the fuel suction chamber 10, and the fuel outflow hole for outflowing the fuel from the fuel discharge chamber 11 to the engine are omitted. There is.

The coil spring 17 for urging the first flexible membrane member 2 in the direction of expanding the pulse pressure chamber 8 depends on the nature of the pulsating pressure introduced into the pulse pressure chamber 8 from the intake pipe or the crankcase. It may or may not be used.

[0006]

In the conventional configuration shown in FIG. 10, the pump casing 1 and the first lid 4 are generally made of metal such as aluminum die casting, and fuel, especially It is necessary to use a heat-insulating resin material when gasoline has a problem of causing vapor lock due to the heat of the engine, but if a thermoplastic resin material that is injection-molded is used, the penetration screw member 7 may be tightened. Thermosetting resins are used because of the problem of creep deformation. However, the productivity of thermosetting resins is poor. Further, even if there is a thermoplastic resin with little creep deformation, it is expensive and difficult to use.

Another problem of the conventional structure shown in FIG. 10 is that the annular gasket 3 and the gasket 3a held together with the first flexible membrane member 2 and the second flexible membrane member 5 are also expensive. When assembling the membrane fuel pump, the pump housing 1
First flexible membrane member 2, one or two annular gaskets 3, first lid 4, second flexible membrane member 5, one or two gaskets 3a, second This means that the man-hours required to stack and tighten the lid 6 increase the cost.

Therefore, even if low-priced thermoplastic resin is used for the pump housing 1, the first lid body 4, and the second lid body 6, creep deformation does not occur and one or two sheets are used. SUMMARY OF THE INVENTION It is an object of the present invention to obtain a membrane fuel pump which does not require the use of the expensive annular gasket 3 described above, as well as one or two expensive gaskets 3a, and can reduce the number of assembling steps.

[0009]

A flexible membrane member is sandwiched between a pump housing and a lid body to provide a space between the pump housing and the flexible membrane member and between the lid body and the lid body. In a membrane fuel pump that forms a space defined by the flexible membrane member with the flexible membrane member, an O-ring rib is formed on an outer peripheral edge of the flexible membrane member, A groove for compressing and accommodating the rib of the outer peripheral edge of the flexible membrane member is provided on the surface of the pump housing that holds the flexible membrane member and the surface of the lid, and the pump housing and the lid body are provided. It is made of a resin material, and the surface of the casing and the surface of the lid are welded to each other at the outer peripheral edge of the groove (claim 1).

The O-ring rib formed on the outer peripheral edge of the flexible film member must be made of an elastic material in order to maintain airtightness, but a resin film having no elasticity is used as the flexible film member. When used, it is necessary to separately form an O-ring rib on the outer peripheral edge of the flexible film member by baking with an elastic material, and this portion may be separated from the resin film. A small hole is provided along the outer peripheral edge of
Ribs formed on both sides of the resin film, which are baked on each side of both sides of the resin film, are connected through the small holes to prevent the ribs from coming off the resin film. 2).

When the above configuration is applied to the conventional pulse pressure type membrane fuel pump shown in FIG. 10, the following configuration is obtained.

Between the pump casing 1 and the first lid 4, there is a first
The flexible membrane member 2 is sandwiched between the pump casing 1 and the second lid 6 to separate the pulsating pressure chamber 8 into which the pulsating pressure of the engine is introduced from the pump action chamber 9. The second flexible membrane member 5 is sandwiched between the fuel suction chamber 10 and the fuel discharge chamber 11, and the air chamber 12 corresponding to the fuel suction chamber 10 and the fuel discharge chamber 11 is separated from each other. In the membrane fuel pump,
The pump housing 1, the first lid body 4, and the second lid body 6 are made of a thermoplastic resin, and are made of a material having elasticity on both outer peripheral edges of the first flexible membrane member 2. The second flexible membrane member 5 forms an O-ring-shaped rib on the outer peripheral edge of the second flexible film member 5 and separates the fuel suction chamber 10 and the fuel discharge chamber 11 from each other, and simultaneously forms the fuel. O-ring-shaped ribs made of an elastic material are formed on both surfaces of a portion that separates the air chamber 12 corresponding to the suction chamber 10 and the air chamber 12 corresponding to the fuel discharge chamber 11, A groove for compressing and accommodating the rib of the first flexible membrane member 2 is provided on the surface of the pump housing 1 that holds the flexible membrane member 2 and the surface of the first lid body 4, The ribs of the second flexible membrane member 5 are compressed and housed on the surface of the pump housing 1 that holds the flexible membrane member 5 and the surface of the second lid body 6. Forming a groove in the periphery of the outer groove, the pump housing 1 and the first cover 4, configurations pump housing 1 and is welded to the second lid 206 (Claim 3).

[0013]

EFFECT OF THE INVENTION Since the pump casing and the lid are made of resin, the fuel inside the pump is better than the membrane fuel pump in which the pump casing and the lid are made of metal having high thermal conductivity. Is rarely heated by the heat of the engine.

Since the pump housing and the lid are joined together by welding and the through screw member is not used for tightening, creep deformation occurs even if an inexpensive thermoplastic resin is used for the pump housing and the lid. I don't.

By eliminating the gasket and the through screw member, the number of parts is reduced, and it becomes possible to use inexpensive thermoplastic resin for the pump housing and the lid, and the cost of parts is reduced.
Assembly man-hours are also reduced and the cost of the membrane fuel pump is reduced.

The weight can be reduced by eliminating the screw member.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a pulse fuel pump according to the present invention. The reference numerals 1, 2, 4, 5, 6, and 8 to 17 are shown in FIG. In addition to showing the same parts as the same reference numerals, 18 is an introduction passage for the pulsating pressure generated in the engine.

Thus, the O-ring-shaped ribs 2 made of an elastic material are formed on both sides of the outer peripheral edge of the first flexible film member 2.
-1 is formed, and the second flexible film member 5 has an O-ring-shaped rib 5 which is made of an elastic material along both outer peripheral edges.
-1 is formed, and the fuel suction chamber 10 and the fuel discharge chamber 11 are formed.
And an air chamber 12 corresponding to the fuel suction chamber 10 and a fuel discharge chamber 11 at the same time.
O-ring-shaped ribs 5-2 made of an elastic material are formed on both surfaces of the part that separates and, and the surface of the pump housing 1 that holds the first flexible membrane member 2 is formed. , The first lid 4
And a groove 1-1 and a groove 4-1 for compressively accommodating the ribs 2-1 on the outer peripheral edge of the first flexible film member 2 are formed on the surface of the second flexible film member 2. Pump housing 1 that holds 5
2 and the surface of the second lid body 6, the ribs of the second flexible membrane member 5, and the groove 1- 1 for compressing and accommodating 5-1 and 5-2, respectively.
2, 1-3 and grooves 6-1 and 6-2 are formed.

When assembling, first the first flexible membrane member 2 is provided between the pump housing 1 and the first lid 4, and the first flexible membrane member 2 is provided between the pump housing 1 and the second lid 6. After holding the second flexible membrane member 5, the contact surface between the outer peripheral edge of the groove 1-1 of the pump housing 1 and the outer peripheral edge of the groove 4-1 of the first lid body 4. The contact surface between the outer peripheral edge of the groove 1-2 of the pump housing 1 and the outer peripheral edge of the groove 6-1 of the second lid 6 is welded by, for example, ultrasonic welding. Reference numeral 19 denotes a welding surface between the pump casing 1 and the first lid body 4,
Reference numeral 20 denotes a welding surface between the pump casing 1 and the second lid 6.

FIG. 2 is a partially enlarged view of the joint surface between the pump housing 1 and the first lid body 4, and the same reference numerals as those in FIG. 1 indicate the same portions. First flexible membrane member 2 shown in FIG.
Shows the case of a rubber cloth containing a base cloth. FIG. 3 shows an enlarged view of a joint portion between the pump housing 1 before assembly and the first lid body 4 or the second lid body 6. Reference numeral 19a denotes an inclined surface of the pump housing 1 on the side facing the first lid 4, forming the welding surface 19, and 20a denotes the pump housing 1 on the side facing the second lid 6. Reference numeral 21 denotes an inclined surface forming the welding surface 20, and reference numeral 21 denotes the inclined surface 19a or the inclined surface of the concentric stepped surface formed on the pump housing 1 side of the first lid 4 or the second lid 6. Two
The welding of the pump housing 1 and the first lid body 4 or the pump housing 1 and the second lid body 6 at the rounded outer peripheral portion facing 0a is performed by the rounded outer peripheral portion 21. And the slope 19
a or contact with the slope 20a. The surface 22 of the pump housing 1, the surface of the first lid body 4 or the surface 23 of the second lid body 6,
That is, the outer surface of the groove and the inner surface of the welding surface have a gap of zero or more after welding, and the surface 2 of the pump housing 1 inside the groove.
4, the surface of the first lid 4 or the surface 25 of the second lid 6 is the first
A gap of zero or more is provided between the flexible membrane member 2 and the surface of the second flexible membrane member 5.

The shape of the joint between the pump housing 1 and the first lid 4 or the second lid 6 can be simplified as shown in FIG. Ribs 2 on the outer peripheral edge of the first flexible film member 2
1 is a groove 1-1 of the pump casing 1 and a groove 4-1 of the first lid 4.
The rib 5-1 on the outer peripheral edge of the second flexible film member 5 according to
Is aligned with the groove 1-2 of the pump casing 1 and the groove 6-1 of the second lid body 6 and welded. 19b is a surface to be welded to the first lid body 4 or the second lid body 6.

FIG. 5 is an enlarged view of the outer peripheral edge portion when a resin film is used for the first flexible film member 2 or the second flexible film member 5. When the base cloth-inserted rubber film is used for the first flexible film member 2 or the second flexible film member 5, the O-ring-shaped rib is made of the same material as the film portion as an elastic material, for example. Although NBR is used and the rib is not supported by the base cloth and does not fall off from the membrane portion, when a resin membrane is used for the membrane portion, the rib is an elastic material and is As in the case, for example, NBR or the like is used, and the material is different from that of the film portion, so that the small hole 2-2 or the small hole 5-3 is provided in the portion where the rib of the film is provided so that the rib does not separate from the film portion. . FIG. 6 shows a state of the film portion before the rib 2-1 is attached to the first flexible film member 2 using the resin film. 2-2 is a small hole that prevents the rib 2-1 from coming off. The small holes in the rib attachment portion of the second flexible film member 5 will be described later.

FIG. 7 shows the shape of the ribs of the first flexible film member 2, and FIG. 8 shows the shape of the ribs of the second flexible film member 5.
The first flexible film member 2 has only the outer peripheral rib 2-1 but the second flexible film member 5 has the outer peripheral rib 5-1 as well as the fuel suction chamber 10 and the fuel discharge chamber. 11 and a rib 5-2 for maintaining airtightness of the partition between the air chamber 12 corresponding to the fuel suction chamber 10 and the air chamber 12 corresponding to the fuel discharge chamber 11. To be FIG. 9 shows a rib 5-1 and a rib 5-2 on the second flexible film member 5.
The state of the film portion before mounting is shown, and 5-3 is a rib 5-
The small holes 5-4 prevent the ribs 5-2 from coming off.

The above-described structure of the present invention is not limited to the pulse pressure type membrane fuel pump having two flexible membrane members, but a pulse pressure type and leverage type fuel having one flexible membrane member. Of course, it can be applied to a pump.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the configuration of a membrane fuel pump of the present invention.

FIG. 2 is a view showing a joint portion between a pump housing and a first lid body.
A partially enlarged view of FIG.

FIG. 3 is a partially enlarged view showing the shape of the joint between the pump housing of FIG. 1 and the first lid or the second lid before joining.

FIG. 4 is a partially enlarged view showing another embodiment of the shape of the joint between the pump housing and the first lid or the second lid.

FIG. 5 is a partially enlarged view showing a shape of a rib forming portion when a resin film is used as a flexible film member.

FIG. 6 is a diagram showing a state before forming ribs on the first flexible film member using a resin film.

FIG. 7 is a diagram showing a rib shape of a first flexible film member.

FIG. 8 is a diagram showing a rib shape of a second flexible film member.

FIG. 9 is a view showing a state before forming ribs on a second flexible film member using a resin film.

FIG. 10 is a sectional view showing an example of a conventional configuration of a membrane fuel pump.

[Explanation of symbols]

 1 Pump Housing 1-1 Groove 1-2 Groove 1-3 Groove 2 First Flexible Membrane Member 2-1 Rib 2-2 Small Hole 4 First Lid 4-1 Groove 5 Second Flexibility Membrane member 5-1 Rib 5-2 Rib 5-3 Small hole 5-4 Small hole 6 Second lid 6-1 Groove 6-2 Groove 8 Pulse pressure chamber 9 Pump action chamber 10 Fuel suction chamber 11 Fuel discharge Chamber 12 Air chamber 13 Intake valve 14 Discharge valve 15 Fuel passage 16 Grommet 17 Coil spring 18 Passage for introducing pulsating pressure of engine 19 Welding surface 19a Slope 19b Welding surface 20 Welding surface 20a Slope 21 Rounded surface Outer circumference

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryo Matsuzaka 309 Toyama, Takizawa, Takizawa-mura, Iwate-gun, Iwate Prefecture Mikuniadek Co., Ltd.

Claims (3)

[Claims] 1. A flexible membrane member is sandwiched between a pump housing and a lid body, and the lid body and the flexible membrane member are sandwiched between the pump housing and the flexible membrane member. In the membrane fuel pump that forms a space defined by the flexible membrane member between the flexible membrane member and the flexible membrane member, an O-ring rib is formed on the outer peripheral edge of the flexible membrane member. A groove for compressing and accommodating the rib of the outer peripheral edge of the flexible membrane member is provided on the surface of the pump housing holding the member and the surface of the lid, and the pump housing and the lid are made of a resin material. And a membrane fuel pump formed by welding the surface of the housing and the surface of the lid at the outer peripheral edge of the groove. 2. An O-ring rib formed by forming the flexible film member with a resin film, providing small holes along the outer peripheral edge of the resin film, and baking the outer peripheral edge of the resin film. 2. The flexible film member according to claim 1, wherein ribs that are baked on both surfaces of the resin film are connected through the small holes to prevent the ribs from being separated from the resin film. 3. A pulse pressure in which a pulsating pressure of an engine is introduced by sandwiching a first flexible membrane member (2) between a pump casing (1) and a first lid (4). The chamber (8) and the pump action chamber (9) are separated from each other, and the second flexible membrane member (5) is held between the pump casing (1) and the second lid (6). hand,
Membrane fuel pump which separates a fuel suction chamber (10) and a fuel discharge chamber (11) from an air chamber (12) corresponding to the fuel suction chamber (10) and the fuel discharge chamber (11). In the pump casing (1), the first lid (4) and the second lid (6) are made of a thermoplastic resin, and both outer peripheral edges of the first flexible membrane member (2) are formed. O-ring-shaped ribs made of an elastic material are formed on the outer periphery of the second flexible membrane member (5). ) And the fuel discharge chamber (11) are separated from each other, and at the same time, an air chamber (12) corresponding to the fuel suction chamber (10) and an air chamber (12) corresponding to the fuel discharge chamber (11) are separated from each other. A flexible O-ring-shaped rib is formed on both sides of the first flexible film member (2).
A groove for compressing and accommodating the rib of the first flexible membrane member (2) is provided on the surface of the pump housing (1) that holds the pump and the surface of the first lid (4), and the second flexible A groove for compressing and accommodating the rib of the second flexible membrane member (5) on the surface of the pump housing (1) holding the flexible membrane member (5) and the surface of the second lid body (6). And a membrane formed by welding the pump casing (1) and the first lid (4), and the pump casing (1) and the second lid (6) at the outer peripheral edge of the groove. Type fuel pump.