JP2001248561A - Pulsation type diaphragm pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable pulsation type diaphragm pump capable of reducing assembling man-hours with redeemed number of parts and having a stable pump action. SOLUTION: This pump consists of valve seat bodies 22, 27 protruding a suction valve 21 and a discharge valve 26 in a pump chamber 6 and a discharge chamber 14 and valve elements 25, 30 formed by parts facing the valve seat bodies 22, 27 of a pump diaphragm 3 and a pulsator diaphragm 10. Two diaphragms 3, 10 reciprocating and displacing by pressure pulsation to feed fuel serve also as the valve elements 25, 30. Air is introduced into a fuel flowing into the pump chamber 6 through an air introduction port 32 to provide the compressibility, and a reciprocating and displacement amount of the pump diaphragm 3 is made large to open and close the suction valve 21 and the discharge valve 26 securely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for supplying fuel to an engine, and more particularly to a pulsating diaphragm pump driven by pressure pulsation generated in a crankcase or an intake manifold as the engine operates. It is.

[0002]

2. Description of the Related Art A pulsating diaphragm pump is a mechanical or electromagnetic pump as a means for supplying fuel to a two-cycle or four-cycle small gasoline engine which is a power source of an agricultural machine, an outboard motor, a light vehicle, or the like. It is widely used because it has an advantage that it has a simpler structure and can be driven without mechanical loss.

FIG. 2 is a cross-sectional view showing an example of a conventional general pulsating diaphragm pump. A pump diaphragm 52 and a cover 53 are overlapped on one surface of a main body 51 and provided on the main body 51. Pump diaphragm 5
The recess covered by 2 forms a pump chamber 54, and the inside of the cover body 53 forms a pulse chamber 55, in which a diaphragm spring 57 is housed.

A pulsator diaphragm 58 and a cap 59 are overlapped on another surface of the main body 51. Two dents provided in the main body 51 and covered by the pulsator diaphragm 58 define a suction chamber 60 and a discharge chamber 62. The interior of the cap 59 is formed in the air chamber 6 communicating with the atmosphere.
4 are formed. 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.

A pressure pulsation of air generated in the crankcase or the intake manifold with the operation of the engine, generally a pressure pulsation generated in the crankcase, is transmitted from a pulse inlet 56 provided in the cover 53 to a pulse chamber 55. After being introduced, the pump diaphragm 52 is reciprocally displaced, and fuel in a fuel tank (not shown) is supplied from the fuel inlet 61 to the suction chamber 60,
The fuel is sent to the fuel outlet 63 through the suction valve 65, the pump chamber 54, the discharge valve 67, and the discharge chamber 62, and supplied to the engine from a carburetor (not shown). The pulsator diaphragm 58 works to smooth the pulsation of the fuel in the suction chamber 60 and the discharge chamber 62 to improve the suction efficiency and the discharge efficiency.

[0006]

The suction valve 65 and the discharge valve 67 are check valves attached to the bottom wall of the main body 51 which divides the pump chamber 54, the suction chamber 60, and the discharge chamber 62.
The valve members 66 and 68 for opening and closing the valve seats that communicate the suction chamber 60 and the pump chamber 54 and the valve seats that communicate the pump chamber 54 and the discharge chamber 62 are the minimum necessary parts, so that the valve can be reliably closed. In order to achieve this, a check valve configured using components such as a valve closing spring that acts on the valve bodies 66 and 68 and a spring receiver that presses the valve closing spring is often used.

For this reason, it is inevitable that the number of components of the pump is large and the number of assembling steps is increased. In particular, since the components of the suction valve 65 and the discharge valve 67 are extremely small and minute components, assembly is troublesome. .

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the suction valve and the discharge valve are configured not to use dedicated fine parts, so that the number of parts is small, and the number of assembling steps is reduced. It is an object of the present invention to provide a pulsating diaphragm pump that can be provided at a low cost and that exhibits a reliable pump function.

[0009]

The present invention provides a fuel suction chamber,
A discharge chamber and a pump chamber, a pump diaphragm that reciprocates and changes the volume of the pump chamber due to a pressure pulsation generated during operation of the engine, and a pulsator diaphragm that smoothes the pulsation of fuel generated in the suction chamber and the discharge chamber. 2. Description of the Related Art A pulsating diaphragm pump having a suction valve that communicates and shuts off a suction chamber and a pump chamber and a discharge valve that communicates and shuts off a pump chamber and a discharge chamber is provided, especially because of a suction valve and a discharge valve. The above-mentioned problem has been solved as follows.

That is, the suction valve has a valve body consisting of a valve seat protruding into the pump chamber and a portion facing the valve seat of the pump diaphragm, and the discharge valve is provided inside the discharge chamber. A protruding valve seat and a valve body comprising a portion of the pulsator diaphragm facing the valve seat were provided.

In the suction stroke in which the pump diaphragm is displaced in the direction of increasing the volume of the pump chamber, the valve body part is separated from the seat surface which is the end face of the valve seat of the suction valve, but the discharge is displaced in the direction of reducing the volume of the pump chamber. During the stroke, the valve body contacts and seats on the seat surface. On the other hand, the valve body portion of the pulsator diaphragm is in contact with and seats on the seat surface which is the end surface of the valve seat of the discharge valve during the suction stroke, but separates from the seat surface during the discharge stroke. In this way, the two reciprocating diaphragms themselves function as the respective valve elements of the suction valve and the discharge valve, and perform the fuel suction and discharge of the pump chamber.

By using the pump diaphragm and the pulsator diaphragm which are originally provided as functional parts for the valve body, the suction valve and the discharge valve are constituted without using dedicated fine parts. Since the number of parts is small, it is possible to reduce the number of assembling steps and provide an inexpensive product.

According to the present invention, as described above, in order for the suction valve and the discharge valve to function properly as check valves and to exhibit a reliable pump function, a fuel suction path from the fuel tank to the suction valve is provided. An air inlet is provided in the fuel cell to mix air into the fuel flowing into the pump chamber.

The amount of reciprocating displacement of the pump diaphragm caused by pressure pulsation generated during operation of the engine is generally very small. This is because the pump chamber is filled with fuel, which is an incompressible fluid, and acts as a resistance to a reciprocating displacement operation. For this reason, unlike the conventional product in which the valve body of the suction valve and the discharge valve is dedicated to opening and closing according to the pressure difference between the pump chamber, the suction chamber, and the discharge chamber, the valve body has a pump diaphragm and a pulsator diaphragm. In the means of the present invention, which is made to be a part and is opened and closed only depending on the amount of reciprocal displacement thereof, when the amplitude of pressure pulsation changes due to the engine operating state, or when there is variation in the dimensions of each pump component However, there is a concern that the opening and closing of the valve may be incomplete and the function as a check valve may not be fulfilled, resulting in a case where the fuel suction efficiency and the discharge efficiency are reduced and the fuel may not be transported.

According to the present invention in which air is mixed into fuel flowing into the pump chamber, the fuel in the pump chamber and the discharge chamber has compressibility due to the mixing of air,
The resistance to the reciprocating displacement of the pump diaphragm is reduced to increase the reciprocating displacement.The reciprocating displacement of the pulsator diaphragm that operates in accordance with the pump diaphragm is also increased, and the opening and closing operations of the suction valve and the discharge valve are ensured. And make it possible to exert a reliable pump function.

It is preferable that the air introduction port is provided with a jet to control the amount of air entrapment. In this case, the fuel can be given appropriate compressibility while securing the required flow rate of the engine. In addition, it is preferable that the diaphragm retainer of the pump diaphragm is eccentric to a position that does not overlap with the valve seat body of the suction valve. Since it works as a valve body, the suction valve can be opened greatly to improve the suction efficiency.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 provided on the main body 1. The depression covered by the pump diaphragm 3 forms a pump chamber 6. The cover body 5 has a pulse introduction hole 7 connected to the crankcase or intake manifold of the engine.
The inside of which forms a pulse chamber 8 and accommodates a diaphragm spring 9.

A pulsator diaphragm 10 and a cap 11 are overlapped on another surface parallel to the above-mentioned surface of the main body 1, and two dents provided in the main body 1 and covered by the pulsator diaphragm 10 are suction chambers. The suction chamber 12 has a fuel inlet 13 connected to a fuel pipe 19 extending from a fuel tank 18, and the discharge chamber 14 has a fuel outlet 15 connected to a carburetor (not shown). Have. The inside of the cap 11 forms an air chamber 16 communicating with the atmosphere.

A pump chamber 6 and a suction chamber 12, which are open to two surfaces of the main body 1 and have recesses provided back to back,
A cylindrical valve seat 22 is provided in the portion of the suction chamber 12 of the bottom wall 2 that partitions the discharge chamber 14 into the interior of the pump chamber 6. The pump chamber 6 has a valve seat port 23 serving as a passage communicating with the pump chamber 6, and a front end surface on the pump chamber 6 side is a seat surface 24.
The seat surface 24 is located at a position close to the pump diaphragm 3, and the seat surface 2 of the pump diaphragm 3 is
The part facing 4 is a valve body 25 for opening and closing the valve seat opening 23.
Work as The above-mentioned valve seat body 22, valve seat opening 23, seat surface 24 and valve body 25 constitute a suction valve 21.

On the other hand, a cylindrical valve seat 27 is provided in the discharge chamber 14 of the bottom wall 2 so as to protrude into the discharge chamber 14, and the valve seat 27 is connected to the pump chamber 6 and the discharge chamber 14. Room 14
And a valve seat port 28 which is a passage for communicating with the discharge chamber 14. The seat surface 29 is located at a position close to the pulsator diaphragm 10, and a portion of the pulsator diaphragm 10 facing the seat surface 29 functions as a valve 30 that opens and closes a valve seat 28. The valve seat 27, the valve seat 28, the seat surface 29 and the valve 30 constitute a discharge valve 26.

Diaphragm retainer 4 superposed on pump diaphragm 3 and receiving diaphragm spring 9
May be concentric with the pump diaphragm 3 as in the conventional product, but in the illustrated embodiment, it is eccentric toward the discharge chamber 14 and the diaphragm retainer 4 overlaps the seat surface 24 when the suction valve 21 is closed. Therefore, only the flexible pump diaphragm 3 is brought into contact with the seat surface 24. Since the portion of the pump diaphragm 3 forming the valve body 25 is greatly displaced without being restricted by the stroke of the diaphragm spring 9, not only is the suction valve 21 opened greatly to increase the fuel flow rate and improve the suction efficiency, but also to improve the suction efficiency. Can be expected to prevent the function as a check valve from being impaired by closing the valve.

In the pump having the structure described above, when pressure pulsation in the crankcase is introduced into the pulse chamber 8 from the pulse introduction port 7 in the crankcase or in the intake manifold with the operation of the engine, the engine piston is moved. The pump diaphragm 3 is displaced toward the pulse chamber 8 by the negative pressure generated by moving to the top dead center to generate a negative pressure in the pump chamber 6, and the valve element 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 of the pump chamber 6 and comes into contact with the seat surface 29 to close the discharge valve 26.

When the pump diaphragm 3 is displaced toward the pump chamber 6 by the positive pressure generated when the engine piston moves to the bottom dead center, the fuel in the pump chamber 6 is pressurized and the pulsator diaphragm 10 is moved to the air chamber 16. And the valve body 30 is separated from the seat surface 29 to send the fuel in the pump chamber 6 from the discharge chamber 14 to the fuel outlet 15. On the other hand, the valve body 25 of the pump diaphragm 3 comes into contact with the seat surface 24 to close the suction valve 21.

By repeating the above, the fuel is supplied to the suction chamber 12.
The suction valve 21 and the discharge valve 26 are formed by the pump diaphragm 3 and the pulsator diaphragm 10 which are functional parts of the pump, and the suction valve 21 and the discharge valve 26 are formed by the pump diaphragm 6 and the pulsator diaphragm 10. Since it has a structure that does not use a dedicated valve element that operates independently, and further does not use a valve closing spring or a spring receiver, it is possible to reduce the number of parts and assembling steps and to provide the device at low cost.

Next, in the illustrated embodiment, an air inlet 32 made of a pipe having a length reaching above the highest fuel position inside the pump is attached to the fuel inlet 13 made of a joint pipe protruding from the main body 1. A jet 33 was mounted on the upper end of the air inlet 32.

When the suction valve 21 is opened and fuel flows from the fuel tank 18 to the pump chamber 6 through the fuel pipe 19, the fuel inlet 13, and the suction chamber 12, air whose flow rate is regulated by the jet 33 is discharged. The entrained fuel is mixed with the fuel flow, and the air-mixed fuel passes through the suction chamber 12, the pump chamber 6, and the discharge chamber 14. Air is mixed in as air bubbles, and the fuel is in a state containing many air bubbles. By setting the air inlet 32 to the above-mentioned length, the inconvenience that fuel overflows from the upper end is eliminated.

As described above, the pump diaphragm 3
Is small, and it may be difficult to expect a sufficiently large displacement even if the valve body 25 is a portion that is not restricted by the stroke by the diaphragm spring 9 as in the illustrated embodiment. In the illustrated embodiment, the fuel inlet 1
By mixing the air with the fuel in step 3, the fuel, which is an incompressible fluid, becomes compressible, and the resistance to the reciprocating displacement operation of the pump diaphragm 3 is reduced to increase the reciprocating displacement. In addition, the reciprocating displacement of the pulsator diaphragm 10 which operates in accordance with the pump diaphragm 3 also increases, and as a result, the stroke of the valve bodies 25 and 30 increases and the amplitude of the pressure pulsation changes, or the size of each pump component is reduced. When there is a variation, complete close contact with the seat surfaces 24 and 29 and sufficient separation from the seat surfaces 24 and 29 are repeated to fulfill the function as a check valve, and a stable pump action can be obtained.

The air inlet 32 is not limited to the fuel inlet 13, but may be provided in the fuel pipe 19 and the suction chamber 12 as a fuel suction path from the fuel tank 18 to the suction valve 21.

[0029]

As described above, according to the present invention, the valve elements of the suction valve and the discharge valve are formed by the pump diaphragm and the pulsator diaphragm which are the functional parts of the pump itself, so that the number of parts is small, and the assembling man-hour is reduced. It can be reduced and provided at low cost. In addition, since the fuel mixed with air is caused to flow into the pump chamber, the reciprocating displacement of the pump diaphragm and the pulsator diaphragm corresponding thereto becomes large, and the suction valve does not impair the function as a check valve. Thus, a reliable pump having a discharge valve can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a conventional example.

[Explanation of symbols]

3 pump diaphragm, 4 diaphragm retainer,
6 pump chamber, 10 pulsator diaphragm, 12 suction chamber, 14 discharge chamber, 21 suction valve, 22, 27 valve seat, 25, 30 valve, 26 discharge valve, 32 air inlet, 33 jet,

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F16K 15/14 F04B 9/12 H // F16K 7/17 21/00 H 31/126 21/02 G F Terms (reference) 3H056 AA07 BB32 BB33 CA08 CB03 CC20 CD10 GG01 GG18 3H058 AA13 BB22 BB29 CA12 CA23 CC01 DD19 EE01 EE15 3H071 AA07 BB01 CC17 CC25 CC31 CC32 CC34 DD03 DD04 DD12 DD13 CC14 DA31 CC32 DA03 CC03 DA03 CC03 DA03 DA16 DA17 DA19 DB10 3H077 AA03 BB01 CC02 DD03 EE01 EE04 EE34 EE35 FF03 FF04 FF12 FF14 FF21 FF60

Claims (3)

[Claims] 1. A pump diaphragm for changing the volume of the pump chamber by reciprocating displacement due to pressure pulsation generated by operation of an engine, a suction chamber, a discharge chamber, and a pump chamber of fuel. A pulsating diaphragm pump including a pulsator diaphragm for smoothing generated fuel pulsation, a suction valve for communicating and shutting off the suction chamber and the pump chamber, and a discharge valve for communicating and shutting off the pump chamber and the discharge chamber. In the above, the suction valve is provided with a valve body comprising a valve seat body protruding into the inside of the pump chamber and a portion of the pump diaphragm facing the valve seat body, and the discharge valve is It is provided with a valve body comprising a valve seat body protruding into the discharge chamber and a portion of the pulsator diaphragm facing the valve seat body. The pulsatile diaphragm pump, characterized in that air inlet openings of mixing air to the fuel flowing into the pump chamber is provided in the fuel inlet path from the fuel tank to the suction valve. 2. The pulsating diaphragm pump according to claim 1, further comprising a jet for regulating an amount of air mixed into said air inlet. 3. The pulsating diaphragm pump according to claim 1, wherein a diaphragm retainer of said pump diaphragm is eccentric to a position not overlapping with a valve seat of said suction valve.