JP4284608B2 - Pulsating diaphragm fuel pump - Google Patents

Description

  The present invention relates to a pulsating diaphragm fuel pump that transports fuel to be supplied to an engine driven by pulsating pressure generated in a crankcase or an intake pipe as the engine is operated.

  2. Description of the Related Art Pulsating diaphragm fuel pumps that have the advantage of being simple in structure and capable of being driven without mechanical loss are widely used as means for transporting fuel supplied to a two-cycle or four-cycle small gasoline engine.

  FIG. 3 is a longitudinal sectional view showing a well-known pulsating diaphragm fuel pump 1D that has been conventionally used. The pump chamber is partitioned by a pump diaphragm 52 into one side of a pump body 53 and a diaphragm cover body 64. 54 and a pulse pressure chamber 55, and on the other side, a suction chamber 57 and a discharge chamber 58 and cushion chambers 59a and 59b defined by pulsator diaphragms 56a and 56b. A suction wall check valve 61 a and a discharge side check valve 61 b are provided on the partition wall 60 that partitions the pump chamber 54, the suction chamber 57, and the discharge chamber 58 of the pump main body 53.

  In the pulsating diaphragm fuel pump 1C, the pulsating pressure generated in the crankcase and the intake pipe, mostly in the crankcase with the operation of the engine, is introduced into the pulsating pressure chamber 55 by the pulsating pressure introducing passage 65, and the pump diaphragm 52 The fuel in the fuel tank that has entered the suction chamber 57 through the fuel inlet 61 is fed into the pump chamber 54 through the suction-side check valve 61a, and discharged through the discharge-side check valve 61b. The fuel is delivered to the chamber 58, sent from a fuel delivery port 62 to a carburetor (not shown), and supplied to the engine.

  However, such a pulsating diaphragm fuel pump 1C has a suction check valve 61a and a discharge check valve 61b on the partition wall 60, as shown in FIG. 4 which is a cross-sectional view taken along line YY of FIG. One check valve is installed, and in addition, these check valves are set to open / close characteristics in a range that works according to the magnitude of pulsation pressure, so the maximum flow rate is limited. In some cases, it is difficult to cope with a case where a large fuel flow rate is required.

  In order to solve this problem, Japanese Patent Laid-Open No. 5-1635 discloses a structure in which two pulsating diaphragm fuel pumps are opposed to each other, and Japanese Patent Laid-Open No. 11-193783 discloses a structure behind the suction chamber and the discharge chamber. A pulsating diaphragm fuel pump provided with a communication passage that allows the cushion chambers to communicate with each other is described.

The former pulsating diaphragm fuel pump achieves a large fuel flow rate by using two pumps, but the pulsating diaphragm fuel used mainly for small engines due to the increase in pump size and cost. It is difficult to install as a pump. On the other hand, the latter pulsating diaphragm fuel pump is a pump that increases the displacement of the pulsator diaphragm by introducing the pressure fluctuation generated in one cushion chamber into the other cushion chamber through the communication path for the cushion chamber partitioned by the pulsator diaphragm. Although an attempt is made to enhance the function, since the open / close characteristics of the suction side check valve and the discharge side check valve do not change, the increase in the fuel flow rate is not sufficient.
JP-A-5-1635 Japanese Patent Laid-Open No. 11-193783

  The present invention is intended to solve the above-described problems, and in a pulsating diaphragm fuel pump, it is possible to cope with an increase in the fuel flow rate without increasing the size of the device or significantly increasing the manufacturing cost. The challenge is to do so.

  Therefore, in the present invention, the pump main body in which the pump chamber is formed and the diaphragm cover body in which the pulse pressure chamber is formed are overlapped on the outer peripheral edge with the pump diaphragm partitioning the pump chamber and the pulse pressure chamber interposed therebetween. The suction side check valve and the discharge side check valve for the pulsating diaphragm fuel pump in which the suction side check valve and the discharge side check valve are installed in the partition wall separating the pump chamber from the suction chamber and the discharge chamber A plurality of valves were provided.

  That is, in the conventional pulsating diaphragm fuel pump, the ratio of the area occupied by the suction side check valve and the discharge side check valve to the area of the partition wall is small. It is possible to easily arrange multiple suction-side check valves and discharge-side check valves, without increasing the size, and increase the fuel transportation capacity with little increase in equipment size and manufacturing cost. Thus, the fuel flow rate can be increased.

  In addition, if the same number of suction side check valves and discharge side check valves installed on the partition wall are arranged so as to be substantially symmetrical with each other, the number of installations can be increased without difficulty. It becomes easy to realize a large fuel flow rate. In this case, the cross-sectional shape of the pump chamber is substantially square, and the suction chamber and the discharge chamber are installed across the partition wall on the bisector, and the suction side check valve and the discharge side check valve are sandwiched between the partition walls. The valves can be installed in the pump chamber at a high density if they are arranged almost symmetrically with each other, but the cross-sectional shape of the pump chamber is substantially square and the suction chamber is sandwiched between the diagonally formed partition walls. If the discharge chamber is installed and the suction-side check valve and the discharge-side check valve are arranged at positions that are close to each other and at opposite angles with the partition wall in between, the number of valves per bottom area of the pump chamber Therefore, it is possible to easily increase the fuel flow rate.

  According to the present invention in which a plurality of suction-side check valves and discharge-side check valves are arranged on the partition wall, the fuel transportation capacity can be increased without increasing the size of the device and significantly increasing the manufacturing cost. Therefore, it is possible to easily increase the fuel flow rate.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is characterized by the arrangement of the suction-side check valve and the discharge-side check valve in the partition wall. The other basic configuration and basic operation of the pulsating diaphragm 1C shown in FIG. Therefore, the description thereof will be omitted, and the characteristic portion will be described in detail with reference to FIGS. 1 and 2.

  FIGS. 1A and 1B show a longitudinal sectional view and a transverse sectional view of a pulsating diaphragm fuel pump 1A according to the first embodiment of the present invention. The configuration of this pulsating diaphragm fuel pump 1A is substantially the same as that of the conventional pulsating diaphragm fuel pump 1C shown in FIG. 3, and a pump body 3A in which a pump chamber 4A is formed and a diaphragm cover body in which a pulsating pressure chamber 5 is formed. 14 is superposed on the outer periphery with the pump diaphragm 2 partitioning the pump chamber 3A and the pulse pressure chamber 5 interposed therebetween, and is sucked into the partition wall 10A that separates the pump chamber 3A from the suction chamber 7A and the discharge chamber 8A. A side check valve 1a and a discharge side check valve 1b are provided.

  In this embodiment, two of these suction-side check valves 1a and two discharge-side check valves 1b are arranged at substantially symmetrical positions with a partition wall 9A separating the suction chamber 7A and the discharge chamber 8A interposed therebetween. In addition, the area of the partition wall 10A and the volume of the pump chamber 3A, the suction chamber 7A, and the discharge chamber 8A are substantially the same as the conventional one shown in FIG. Further, each suction side check valve 1a has one suction chamber 7A, to which the fuel introduction port 11 is connected, and each discharge side check valve 1b also has one discharge chamber 8A, to which fuel is fed. An outlet 12 is connected.

  The two suction-side check valves 1a and the two discharge-side check valves 1b are simultaneously opened / closed to greatly increase the flow rate of fuel passing through them, so that the pump chamber 4A, the suction chamber 7A, the discharge chamber The pressure change of 8A becomes large, and as a result, a large amount of fuel can be transported following the displacement of the pump diaphragm 2.

  FIG. 2A shows a second embodiment of the present invention, wherein the suction chamber 7B and the discharge chamber are sandwiched by sandwiching a partition wall 9B provided on the diagonal line with the cross-sectional shape of the pump chamber 4B being substantially square. A pulsating diaphragm fuel pump 1B is provided, in which a suction side check valve 1a and a discharge side check valve 1b are arranged at diagonally opposite positions on both sides of the partition wall 9B. Show. The pump chamber 4B in this embodiment has a cross-sectional shape that is substantially square with four corners rounded and chamfered, and includes three suction-side check valves 1a, 1a, and 1a and three discharge-side check valves 1b. , 1b, 1b are arranged. Further, the suction chamber 7B of each suction side check valve 1a and the discharge chamber 8B of each discharge side check valve 1b are one each, and the cross-sectional shape is substantially an isosceles triangle. A fuel delivery port 12 is connected.

  With this configuration, the suction-side check valve 1a and the discharge-side check valve 1b can be installed at a high density on the partition wall 10B. It is possible to greatly increase the flow rate of fuel passing through the hour, and to make the fuel transport capacity of the pump extremely high.

  FIG. 2 (B) shows a third embodiment of the present invention. In the partition wall 10C, three suction side check valves 1a and three discharge side check valves 1b are respectively connected to two pump chambers 4C. A pulsating diaphragm fuel pump 1C is shown that is arranged on a straight line and substantially symmetrical with respect to a partition wall 9C provided on an equidistant line. In the present embodiment, the suction-side check valves 1a, 1a, 1a and the discharge-side check valves 1b, 1b, 1b are substantially in line with the suction chamber 7C and the discharge chamber 8C having a substantially rectangular cross section. is set up. By adopting such a configuration, the fuel transport capability of the pump can be made extremely high as in the pulsating diaphragm fuel pump 1B of FIG.

  As described above, by installing a plurality of suction side check valves and discharge side check valves on the partition wall, the fuel transport capacity can be sufficiently increased in a limited pump size. It is possible to easily realize a large fuel flow rate while avoiding an increase in size and a significant increase in manufacturing cost.

(A) is a cross-sectional view showing the first embodiment of the present invention, (B) is a cross-sectional view along the line XX. (A) is a cross-sectional view showing a second embodiment of the present invention, (B) is a cross-sectional view showing a third embodiment of the present invention. The longitudinal cross-sectional view which shows a prior art example. Sectional drawing which follows YY of FIG.

Explanation of symbols

1A, 1B, 1C Pulsating diaphragm fuel pump, 1a Suction side check valve, 1b Discharge side check valve, 2 Pump diaphragm, 3A, 3B, 3C Pump body, 4A, 4B, 4C Pump chamber, 5 Pulse pressure chamber, 7A, 7B, 7C Suction chamber, 8A, 8B, 8C Discharge chamber, 9A, 9B, 9C Partition, 10A, 10B, 10C Partition wall, 14 Diaphragm cover body

Claims (1)

The pump body in which the pump chamber is formed and the diaphragm cover body in which the pulse pressure chamber is formed are overlapped at the outer peripheral edge with the pump diaphragm partitioning the pump chamber and the pulse pressure chamber interposed therebetween, In a pulsating diaphragm fuel pump in which a suction side check valve and a discharge side check valve are installed in a partition wall separating the chamber, the suction chamber and the discharge chamber,
The pump chamber has a substantially square cross-sectional shape, and a suction chamber and a discharge chamber are provided with a partition formed on the diagonal line, and a plurality of suction-side check valves and discharge-side check valves are sandwiched between the partition walls. A pulsating diaphragm fuel pump, characterized in that the pulsating diaphragm fuel pump is disposed at positions that are close to each other and substantially diagonal to each other .

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