JP4392636B2 - Pulsating diaphragm pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulsating diaphragm pump that is driven by pressure pulsation generated in a crankcase or an intake manifold as the engine is operated, and is used to supply fuel mainly to a two-cycle gasoline engine.
[0002]
[Prior art]
Pulsating diaphragm pumps have a structure compared to mechanical and electromagnetic pumps as a means of supplying fuel to small or double-cycle gasoline engines that are power sources for agricultural machinery, outboard motors, and mini vehicles. Is widely used because it has the advantages of being simple and capable of being driven without mechanical loss.
[0003]
FIG. 4 is a cross-sectional view showing an example of a conventional general pulsating diaphragm pump, in which a pump diaphragm 52 and a cover body 53 are overlapped on one surface of a main body 51 and provided on the main body 51. The hollow covered with the diaphragm 52 forms a pump chamber 54, and the inside of the cover body 53 forms a pulse chamber 55 and houses a diaphragm spring 57.
[0004]
A pulsator diaphragm 58 and a cap 59 are overlapped on the other surface of the main body 51, and two recesses provided in the main body 51 and covered with the pulsator diaphragm 58 form a suction chamber 60 and a discharge chamber 62, The cap 59 forms an air chamber 64 communicating with the atmosphere. Further, a suction valve 65 is provided between the suction chamber 60 and the pump chamber 54, and a discharge valve 67 is provided between the pump chamber 54 and the discharge chamber 62.
[0005]
The pressure pulsation of air generated in the crankcase or the intake manifold as the engine is operated, and generally the pressure pulsation generated in the crankcase is introduced into the pulse chamber 55 from the pulse introduction port 56 provided in the cover body 53. The pump diaphragm 52 is reciprocally displaced, and fuel in a fuel tank (not shown) is sent from the fuel inlet 61 to the fuel outlet 63 via the suction chamber 60, the suction valve 65, the pump chamber 54, the discharge valve 67, and the discharge chamber 62, and is not shown in the figure. Supplied to the engine from the vessel. In the suction chamber 60 and the discharge chamber 62, the pulsation of the fuel is smoothed by the pulsator diaphragm 58, so that the suction efficiency and the discharge efficiency are improved.
[0006]
[Problems to be solved by the invention]
The suction valve 65 and the discharge valve 67 are check valves attached to the bottom wall that partitions the pump chamber 54, the suction chamber 60, and the discharge chamber 62 of the main body 51, and are valves that communicate the suction chamber 60 and the pump chamber 54. The valve bodies 66 and 68 that open and close the valve seats communicating with the seat ports and the pump chamber 54 and the discharge chamber 62 are the minimum necessary parts, and act on the valve bodies in order to ensure the valve closing. Many check valves are also used which are constructed using parts such as a valve closing spring and a spring receiver for holding the valve closing spring.
[0007]
For this reason, it is difficult to meet the demand for purchasing a pump having a reliable pump function at a low cost with a large number of pump components and a large number of assembly steps.
[0008]
The present invention has been made to solve such a problem, and the number of parts is small, so that the assembly man-hour can be reduced and it can be provided at a low cost, and the reliability for the pump function is impaired. It aims at obtaining the pulsation type diaphragm pump which does not have this.
[0009]
[Means for Solving the Problems]
The present invention relates to a fuel suction chamber and a discharge chamber, a pump chamber, a pump diaphragm that reciprocally displaces due to pressure pulsation generated by engine operation, and a volume of the fuel generated in the suction chamber and the discharge chamber. There is a pulsating diaphragm pump comprising a pulsator diaphragm for smoothing pulsation, a suction valve for communicating / blocking the suction chamber and the pump chamber, and a discharge valve for communicating / blocking the pump chamber and the discharge chamber. The above-mentioned problem caused by the suction valve and the discharge valve is solved as follows.
[0010]
That is, for the suction valve, the valve seat is protruded into the pump chamber, and the valve body that opens and closes the valve seat opening by contacting and separating from the seat surface that is the end face thereof faces the valve seat body of the pump diaphragm. It was. For the discharge valve, the valve seat is protruded into the discharge chamber, and the valve body that opens and closes the valve seat opening by contacting and separating from the seat surface, which is the end face, faces the valve seat of the pulsator diaphragm. It was.
[0011]
The pump diaphragm moves away from the seat surface in the suction stroke that is displaced in the direction of expanding the pump chamber volume, but is in contact with the seat surface in the discharge stroke that is displaced in the direction of reducing the volume of the pump chamber. On the other hand, the pulsator diaphragm contacts and seats on the sheet surface in the suction stroke, but moves away from the sheet surface in the discharge stroke. As described above, the two diaphragms that reciprocally move themselves function as the valve bodies of the suction valve and the discharge valve, respectively, so that the fuel suction and discharge in the pump chamber can be appropriately performed.
[0012]
And by using the pump diaphragm and pulsator diaphragm conventionally provided as functional parts in this way for the valve body, it is possible to reduce the number of parts, thus reducing the number of assembly steps and providing it at low cost. The object of obtaining a reliable pulsating diaphragm pump that does not impair the functions of the suction valve and the discharge valve as a check valve is achieved.
[0013]
In order to ensure complete contact and seating of the valve body on the seat surface when the suction valve and discharge valve are closed, the diaphragm retainer of the pump diaphragm is eccentrically provided at a position that does not overlap the seat surface. Alternatively, it is preferable that the pump diaphragm is formed in a flat surface shape and is in contact with the sheet surface in a flat surface state. In addition, for either or both of the suction valve and the discharge valve, the seat surface of the valve seat body is formed by an elastic seal member, or the valve body portion of the diaphragm is formed to be thickened toward the seat surface. Alternatively, it is preferable that the diaphragm base fabric is shifted to the surface opposite to the sheet surface.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. 1. A pump diaphragm 3 and a cover body 5 are overlapped on one surface of a main body 1, and are provided on the main body 1 and covered with the pump diaphragm 3. The depression forms a pump chamber 6. The cover body 5 has a pulse introduction port 7 connected to an engine crankcase or an intake manifold, and the inside of the cover body 5 forms a pulse chamber 8 and houses a diaphragm spring 9.
[0015]
A pulsator diaphragm 10 and a cap 11 are overlapped on another surface parallel to the surface of the main body 1, and two recesses provided in the main body 1 and covered with the pulsator diaphragm 10 are a suction chamber 12 and a discharge chamber. 14, the suction chamber 12 has a fuel inlet 13 connected to the fuel tank, and the discharge chamber 14 has a fuel outlet 15 connected to the vaporizer. The inside of the cap 11 forms an air chamber 16 communicating with the atmosphere.
[0016]
A cylindrical valve is provided in the suction chamber 12 of the bottom wall 2 that defines the pump chamber 6, the suction chamber 12, and the discharge chamber 14 that are formed on the two surfaces of the main body 1 so as to be formed back to back. A seat body 22 is provided so as to protrude into the pump chamber 6, and the valve seat body 22 has a valve seat port 23 that is a passage communicating the suction chamber 12 and the pump chamber 6, and is provided on the pump chamber 6 side. The front end surface is a sheet surface 24. The seat surface 24 is located at a position close to the pump diaphragm 3 so that the pump diaphragm 3 which is reciprocally displaced contacts at an appropriate position in the middle of the displacement stroke, and a portion of the pump diaphragm 3 facing the seat surface 24 is a valve seat. It functions as a valve body 25 that opens and closes the mouth 23. The valve seat body 22, the valve seat port 23, the seat surface 24, and the valve body 25 constitute a suction valve 21.
[0017]
On the other hand, a cylindrical valve seat 27 is provided in a portion of the discharge chamber 14 of the bottom wall 2 so as to protrude into the discharge chamber 14. The valve seat 27 includes the pump chamber 6, the discharge chamber 14, and the like. And a front end surface on the discharge chamber 14 side is a sheet surface 29. The seat surface 29 is located at a position where the pulsator diaphragm 10 comes into contact with the non-operating position when the engine is stopped or at an appropriate position in the middle of the reciprocating displacement stroke, and the portion facing the seat surface 29 of the pulsator diaphragm 10 is the valve seat 28. It functions as a valve body 30 that opens and closes. The valve seat body 27, the valve seat port 28, the seat surface 29, and the valve body 30 constitute a discharge valve 26.
[0018]
The diaphragm retainer 4 that is superimposed on the pump diaphragm 3 and receives the diaphragm spring 9 may be concentric with the pump diaphragm 3 in the same manner as the conventional product. However, in the embodiment shown in FIG. The diaphragm retainer 4 does not overlap the seat surface 24 when the suction valve 21 is closed, and only the flexible pump diaphragm 3 overlaps the seat surface 24 so that the valve can be completely closed. . Further, in this way, the pump diaphragm 3 contacts and separates from the seat surface 24 with a portion of the diaphragm spring 9 that is not generally limited by a small stroke as a valve body 25, so that the intake valve 21 is opened largely to make the fuel The flow rate can be increased.
[0019]
In the present embodiment having such a configuration, when pressure pulsation generated in the crankcase as the engine is operated is introduced into the pulse chamber 8 from the pulse introduction port 7, the engine piston moves to the top dead center. Due to the negative pressure, the pump diaphragm 3 is displaced toward the pulse chamber 8 to generate a negative pressure in the pump chamber 6 and the valve body 25 is separated from the seat surface 24. As a result, the fuel in the suction chamber 12 flows into the pump chamber 6, while the pulsator diaphragm 10 is sucked by the negative pressure in the pump chamber 6 and is brought into close contact with the seat surface 29 to close the discharge valve 26.
[0020]
When the pump diaphragm 3 is displaced toward the pump chamber 6 by the positive pressure generated by the movement of the engine piston to the bottom dead center, the fuel in the pump chamber 6 is pressurized and the pulsator diaphragm 10 is displaced toward the air chamber 16. Then, when the valve body 30 is separated from the seat surface 29, the fuel in the pump chamber 6 is sent from the discharge chamber 14 to the fuel outlet 15. On the other hand, the valve body 25 of the pump diaphragm 3 is brought into contact and contact with the seat surface 24 to close the suction valve 21.
[0021]
By repeating the above, the fuel is sent from the suction chamber 12 to the discharge chamber 14 through the pump chamber 6, and at this time, the suction valve 21 and the discharge valve 26 use the valve bodies 25 and 30 as the pump diaphragm 3, pulsator which are functional parts of the pump. By using the diaphragm 10 which is formed by the diaphragm 10 and does not use a dedicated valve body which operates independently by a pressure difference, the strokes of the two diaphragms 3, 10 in particular the valve bodies 25 and 30 and the positions of the seat surfaces 24 and 29 Therefore, a large fuel flow rate can be easily obtained.
[0022]
Next, FIG. 2 (A) shows a flat surface shape in which the peripheral portion sandwiching the pump diaphragm 3 between the main body 1 and the cover body 5 and the effective diameter portion that is reciprocally displaced are located on the same plane at the non-operating position when the engine is stopped. In this state, the valve body 25 is in contact with the seat surface 24. The flat surface shape is the same as that of the pulsator diaphragm 10 and completes the closing of the suction valve 21 during the discharge stroke.
[0023]
Further, in FIG. 2B, in order to complete the closing of the suction valve 21 and the discharge valve 26, a seal member 32 made of an O-ring is attached to the tip portions of the valve seat bodies 22 and 27, and the valve The seat surfaces 24 and 29 with which the bodies 25 and 30 come into contact with and away from each other are formed by the elastic seal member 32, and the valve bodies 25 and 30 of the diaphragms 3 and 10 are in elastic contact with the seal member 32. Make a complete close-close state.
[0024]
Further, FIG. 2C is also an embodiment for causing the suction valve 21 and the discharge valve 26 to be completely closed. In this structure, the valve bodies 25 and 30 facing the seat surfaces 24 and 29 at the tips of the valve seat bodies 22 and 27 are thickened so that these portions of the diaphragms 3 and 10 are raised toward the seat surfaces 24 and 29. The valve closing force which is formed by the above and the rubber member which is the material of the diaphragms 3 and 10 is strengthened in the portions of the valve bodies 25 and 30 so as to be completely in close contact with the seat surfaces 24 and 29 Make a state.
[0025]
Further, FIG. 2D is an embodiment for causing the suction valve 21 and the discharge valve 26 to be completely closed. This is one in which a base cloth 34 embedded in the diaphragms 3 and 10 is embedded by being offset to the surface opposite to the sheet surfaces 24 and 29, and the elastic force possessed by the rubber that is the material of the diaphragms 3 and 10. The valve bodies 25 and 30 are brought into contact with the seat surfaces 24 and 29 by fully utilizing the above, thereby creating a complete valve closing state.
[0026]
The embodiments shown in FIGS. 2B, 2C, and 2D are not necessarily applied to both the suction valve 21 and the discharge valve 26, and can be applied to only one of them. Further, different embodiments can be appropriately selected and applied to the suction valve 21 and the discharge valve 26. For example, the one shown in FIGS. 2B, 2C, and 2D is applied to the discharge valve 26 in the embodiment shown in FIG.
[0027]
Fig. 3 shows a comparison test of the fuel flow rate with that of the embodiment shown in Fig. 1 in which six pulsating diaphragm pumps manufactured and sold at home and abroad are of the same capacity are selected. The results are shown, and it can be seen that the present invention product provides a larger fuel flow rate than the conventional products No.1, No.2, No3, No.4, No.5, No.6. It was.
[0028]
【The invention's effect】
As described above, according to the present invention, the valve body of the suction valve and the discharge valve is formed by the pump diaphragm and the pulsator diaphragm which are functional parts of the pump itself, so that the number of parts is small, and therefore, the number of assembly steps can be reduced and the cost can be reduced. It is possible to provide a reliable pump having a suction valve and a discharge valve that does not impair the function as a check valve because it is opened and closed using the reciprocal displacement of each diaphragm. is there. In addition, it is possible to easily obtain a large fuel flow rate as compared with the conventional one.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
2 (A), (B), (C), and (D) are longitudinal sectional partial views showing different embodiments of the present invention. FIG.
FIG. 3 is a performance comparison diagram between the product of the present invention and the conventional product.
FIG. 4 is a longitudinal sectional view showing a conventional example.
[Explanation of symbols]
3 Pump diaphragm, 4 Diaphragm retainer, 6 Pump chamber, 9 Diaphragm spring, 10 Pulsator diaphragm, 12 Suction chamber, 14 Discharge chamber, 21 Suction valve, 22, 27 Valve seat body, 23, 28 Valve seat port, 24, 29 seat Surface, 25, 30 valve body, 26 discharge valve, 32 seal member,

Claims (6)

Fuel suction chamber and discharge chamber, pump chamber, pump diaphragm that reciprocally displaces due to pressure pulsation generated by engine operation, and pulsation of fuel generated in the suction chamber and discharge chamber In a pulsating diaphragm pump comprising a pulsator diaphragm for smoothing, a suction valve for communicating / blocking the suction chamber and the pump chamber, and a discharge valve for communicating / blocking the pump chamber and the discharge chamber,
The suction valve projects the valve seat into the pump chamber, and contacts and separates the valve seat from the seat surface which is the end face of the suction valve to face the valve seat of the pump diaphragm. The discharge valve has a valve seat that projects into the interior of the discharge chamber and that opens and closes the valve seat opening by contacting and separating from the seat surface that is the end face thereof. A pulsating diaphragm pump, characterized in that the pulsator diaphragm is formed at a portion facing the valve seat body of the pulsator diaphragm. 2. The pulsating diaphragm pump according to claim 1, wherein a diaphragm retainer of the pump diaphragm is eccentrically provided at a position not overlapping with a seat surface of the suction valve. 2. The pulsating diaphragm pump according to claim 1, wherein the pump diaphragm is formed in a flat surface shape and is brought into contact with a seat surface of the suction valve in a flat surface state. The seat member which is elastic is provided in the valve seat body of at least one of the suction valve and the discharge valve, and the seat surface which the valve body contacts / separates is formed with the seal member. Pulsating diaphragm pump. 2. The pulsating diaphragm pump according to claim 1, wherein the valve body portion of at least one of the pump diaphragm and the pulsator diaphragm is formed to have a thick wall rising toward the seat surface. 2. The pulsating diaphragm pump according to claim 1, wherein at least one base fabric of the pump diaphragm and the pulsator diaphragm is offset to a surface opposite to the seat surface.

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