JP2001099008A - Negative pressure type fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically reset a discharge pressure of a fuel pump when it is lowered to a specified value or less in a negative pressure type fuel supply device. SOLUTION: A pump chamber P is determined by a pump diaphragm 3 and a left side surface 1A of a pump main body 1, while a pulsative pressure chamber A is determined by the pump diaphragm 3 and a first cover 2. First and second fuel chambers F1, F2 are determined by a damper diaphragm 5 and a right side surface 1C of the pump main body 1. A damper chamber D are determined by the damper diaphragm 5 and a second cover 4. A third fuel chamber F3 is determined by a regular diaphragm 7 and an upper side surface 1G of the pump main body 1. A spring chamber S is determined by the regular diaphragm 7 and a fourth cover 6. An accumulation chamber C is determined by an accumulation diaphragm 16 and the right side surface 1C of the pump main body 1. An atmospheric chamber E is determined by the accumulation diaphragm 16 and a third cover 15. The accumulation chamber C is communicated with the third fuel chamber F3 through a seventh flow passage G7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump chamber which is divided by a pump diaphragm and increases or decreases the volume of the pump chamber by a pulsating pressure, thereby sucking fuel in a fuel source into the pump chamber and increasing the pressure.
The present invention relates to a negative pressure type fuel supply device which regulates the boosted fuel pressure to a constant pressure and supplies it to a consuming unit, and is used for a fuel supply device of an internal combustion engine, for example.

[0002]

2. Description of the Related Art A negative pressure type fuel pump which performs a pumping operation by increasing or decreasing a chamber volume of a pump chamber by a pulsating pressure is well known. This means that a pump diaphragm is sandwiched between a pump body and a cover to form a pump chamber and a pulsating pressure chamber, and a suction path having a suction-side check valve and a discharge path having a discharge-side check valve in the pump chamber. Opens. Pulsating pressure is introduced into the pulsating pressure chamber through a pressure passage, whereby the pump diaphragm increases or decreases the volume of the pump chamber by the pulsating pressure, and the fuel in the fuel source is pumped through the suction path. The fuel that is sucked into the room and then pressurized in the pump chamber is supplied to an external consuming unit via a discharge path.
On the other hand, a fuel pressure control valve that regulates a boosted fuel pressure to a constant pressure is also well known, and a partition body having a valve body is sandwiched between an upper end of a valve body and a lower end of a cover, and the partition body A fuel chamber is formed on the valve body side, and a spring chamber is separately formed on the cover side. The fuel chamber has a concave shape, the fuel inflow path and the fuel outflow path open in the fuel chamber, and the fuel return path further includes a valve seat that is opened and closed by a valve body that moves synchronously with the partition body. Open to When the fuel pressurized from the fuel inflow passage flows into the fuel chamber, the partition operates according to the pressure in the fuel chamber. When the fuel pressure in the fuel chamber rises above a predetermined pressure, the partition moves to the spring chamber side. And the valve element opens the valve seat to discharge fuel from the fuel return passage. According to the above,
The pressure in the fuel chamber is controlled to a predetermined pressure, and the fuel controlled to the predetermined pressure is supplied to the outside from a fuel outflow passage.

[0003]

The conventional fuel supply apparatus having the negative pressure type fuel pump and the fuel pressure control valve individually has the following disadvantages. (1) When the pressure of the fuel introduced from the negative pressure type fuel pump into the fuel chamber of the fuel pressure control valve temporarily decreases, the fuel pressure toward the consuming unit also decreases in synchronization with the predetermined pressure determined by the consuming unit. Cannot supply fuel. For example, when the pulsation pressure applied to the pulsation pressure chamber of the negative pressure fuel pump temporarily decreases, the fuel pressure discharged from the fuel pump also decreases in synchronization with the pulsation pressure. This reduced fuel pressure acts.
According to this, even if the valve opening time of the fuel injection valve is controlled to a predetermined time, the amount of fuel injected from the fuel injection valve toward the engine temporarily corresponds to the pressure drop. Become. (2) The negative pressure type fuel pump and the fuel pressure control valve that constitute the fuel supply device are separately prepared, and according to this, the device cannot be made compact. The number of parts increases, resulting in high manufacturing costs. A pipe connection between the fuel pump and the pressure control valve is required, and the appearance is poor. The problem described above occurs. According to the above, it is inconvenient to dispose the fuel supply device in a limited space, such as a motorcycle. Exposing the pipe to the outside is not preferable in terms of the appearance of the motorcycle.

[0004] The negative pressure type fuel supply device according to the present invention has been made in view of the above-mentioned problem, and the fuel pressure supplied from the negative pressure type fuel pump to the fuel pressure control valve is temporarily reduced to a pressure below a certain value. Provided is a negative-pressure fuel supply device capable of suppressing the pressure drop and automatically raising the fuel pressure to the original pressure value and returning when the pressure drops.
It is another object of the present invention to provide a negative-pressure fuel supply device for supplying fuel adjusted to a constant pressure at a small size and at a low cost, and to provide the device excellent in mountability and appearance in particular on a motorcycle.

[0005]

In order to achieve the above object, a negative pressure type fuel supply device according to the present invention has a pump diaphragm sandwiched between a left side surface of a pump body and a first cover covering the same, and a right side of the pump diaphragm. A pump chamber is formed by the surface and the pump body, a pulsating pressure chamber is formed by the left side surface of the pump diaphragm and the first cover, and a damper diaphragm is sandwiched by the right side surface of the pump body and the second cover covering the pump body. A first fuel chamber and a second fuel chamber separated from each other by the left side surface of the damper diaphragm and the pump body; a damper chamber formed by the right side surface of the damper diaphragm and the second cover; The pressure accumulating diaphragm is sandwiched between the right side surface and the third cover that covers the right side surface, and the left side surface of the pressure accumulating diaphragm and the pump body are sandwiched. A pressure accumulator is formed by the pressure accumulator diaphragm, an atmosphere chamber is formed by the right side surface of the pressure accumulator diaphragm and the third cover, and a regulator diaphragm is sandwiched by an upper surface of the pump body and a fourth cover covering the pump body. A third fuel chamber is formed by the lower surface and the pump body, a spring chamber is formed by the upper surface of the regulator diaphragm and the fourth cover, a pressure passage is opened in the pulsating pressure chamber, and a fuel source is formed in the first fuel chamber. A second flow path having one end connected to the pump chamber and one end connected to the pump chamber and having a suction-side check valve is opened, and a second fuel chamber having one end connected to the pump chamber and having a discharge-side check valve. The third flow path and the fourth flow path connected to the third fuel chamber are opened, and the third fuel chamber is provided with the fourth flow path.
A fifth flow path that opens with a flow path and a valve seat, a sixth flow path that connects to the consuming unit, and a seventh flow path that connects to the pressure accumulating chamber are opened, and a valve unit that moves synchronously with the regulator diaphragm in the spring chamber is valved. A first feature is that a regulator spring that presses toward the seat is contracted and a pressure accumulating spring that presses the pressure accumulating diaphragm toward the pressure accumulating chamber is contracted in the atmosphere chamber.

[0006] The present invention provides a third aspect in addition to the first aspect.
A second feature is that the flow path is disposed above the second flow path in the direction of gravity, and the third fuel chamber is disposed further above the third flow path.

Further, the present invention has a third feature in that a jet is disposed in one or both of the fourth and fifth flow paths in addition to the first invention.

[0008] The present invention further provides a fourth aspect in addition to the first aspect.
A fourth feature is that the flow path and the seventh flow path are formed in the pump body.

Further, the present invention provides a seventh aspect in addition to the first aspect.
A fifth feature is that the flow path is opened at a position above the accumulator in the direction of gravity.

Further, according to the present invention, in addition to the first aspect, the pressure accumulating spring is a coil spring, and a large-diameter coil spring having a large diameter and a small-diameter coil spring having a small diameter are arranged in parallel in an atmosphere chamber. This is the sixth feature.

[0011]

According to the first feature of the present invention, when the pressure of the fuel flowing into the third fuel chamber rises above a certain value, the valve portion opens the valve seat to allow the fuel in the third fuel chamber to flow through the fifth fuel chamber. The fuel is discharged to the outside through the passage, whereby the fuel adjusted to a constant pressure is supplied from the sixth passage toward the consuming portion. On the other hand, the constant fuel pressure in the third fuel chamber is introduced into the accumulator through the seventh flow path, and the accumulator diaphragm is displaced toward the atmosphere chamber against the spring force of the accumulator spring, and The volume is increased to accumulate fuel pressure in the accumulator. Here, when the fuel pressure in the third fuel chamber decreases to a pressure equal to or lower than a certain value and the pressure in the accumulator decreases in synchronism therewith, the accumulator diaphragm is displaced toward the accumulator by the spring force of the accumulator spring and accumulates. The volume of the chamber can be reduced, and the boosted fuel pressure in the accumulator can be applied to the sixth flow path via the third fuel chamber. In addition, the pump body is provided with a pump chamber having a pumping function, first and second fuel chambers, a third fuel chamber having a pressure regulating function, and a pressure accumulating chamber having a pressure accumulating function. Can be achieved.

According to the second feature of the present invention, bubbles generated in the vicinity of the pump chamber can be converged to the third fuel chamber located at an upper position, and this can be effectively conveyed through the fifth flow path which opens to the atmosphere. Can be discharged.

According to the third feature of the present invention, the pressure fluctuation of the fuel flowing from the fourth flow passage into the third fuel chamber can be suppressed, and the pressure fluctuation of the fuel discharged through the fifth flow passage can be suppressed. Is suppressed, so that the fuel discharged from the sixth flow path toward the consuming portion can be further suppressed.

According to a fourth feature of the present invention, a fourth passage serving to connect the negative pressure type fuel pump to the fuel pressure control valve and a fourth passage serving to connect the fuel pressure control valve to the pressure accumulator are provided. Since the seven flow paths are formed in the pump main body, the pipe connection can be reduced, the external appearance can be simplified, and the compatibility with the motorcycle can be improved in combination with the compactness.

According to the fifth aspect of the present invention, bubbles generated in the accumulator can be discharged through the seventh flow path.

According to the sixth aspect of the present invention, the spring constant of the spring in the atmosphere chamber can be reduced, the responsiveness to the fluid pressure acting in the pressure accumulating chamber can be improved, and the atmosphere in which the spring is housed can be obtained. The overall height of the room can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a negative pressure type fuel supply apparatus according to the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a pump body, which is provided with a pump chamber concave portion 1B in a left side surface 1A thereof, and a right side surface 1A.
C, a first fuel chamber recess 1E and a second fuel chamber recess 1F separated from each other by a partition 1D are recessed, a pressure accumulation chamber recess 1L is recessed, and a third fuel chamber recess 1H is further formed on an upper surface 1G. It is recessed.

The pump diaphragm 3 is sandwiched between the left side surface 1A of the pump body 1 and the first cover 2 covering the left side surface 1A, whereby the pump chamber P is formed by the right side surface 3A of the pump diaphragm 3 and the pump chamber recess 1B. The left side 3B of the pump diaphragm 3 and the first cover 2
Thus, the pulsating pressure chamber A is formed. In the pulsating pressure chamber A, a pressure passage A1 is opened.
A pulsating pressure generated in the engine is introduced via the pulsating pressure.

A damper diaphragm 5 is sandwiched between a right side surface 1C of the pump body 1 and a second cover 4 covering the same, whereby the left side surface 5 of the damper diaphragm 5 is formed.
A and the first fuel chamber recess 1E form a first fuel chamber F1, and the left side face 5A and the second fuel chamber recess 1F form a second fuel chamber F2. At this time, the first fuel chamber F1 and the second It is isolated from the second fuel chamber F2 by the partition 1D. Then, the right side surface 5B of the damper diaphragm 5 and the second cover 4
Thus, a damper chamber D facing the first and second fuel chambers F1 and F2 is formed.

A pressure accumulating diaphragm 16 is sandwiched between the right side 1C of the pump body 1 and the third cover 15 covering the same, whereby the pressure accumulating chamber C is defined by the left side 16A of the pressure accumulating diaphragm 16 and the pressure accumulating chamber recess 1L. An atmosphere chamber E is formed by the right side surface 16B of the pressure accumulating diaphragm 16 and the third cover 15. The pressure-accumulating diaphragm 16 is urged toward the pressure-accumulating chamber C by a pressure-accumulating spring 17 contracted into the atmosphere chamber E. When the pressure in the pressure-accumulating chamber C is low, the pressure-accumulating diaphragm 16 is on the right side and Keep the chamber volume of C to a minimum.

The regulator diaphragm 7 is sandwiched between the upper surface 1G of the pump body 1 and the fourth cover 6 covering the upper surface 1G, whereby the lower surface 7A of the regulator diaphragm 7 and the third fuel chamber recess 1H form the third fuel chamber. F3 is formed, and a spring chamber S is formed by the upper surface 7B of the regulator diaphragm 7 and the third cover 6.

The first fuel chamber F1 has a first fuel chamber T connected to the first fuel chamber T1.
The flow path G1 and a second flow path G2 connected to the pump chamber P are open, and the second flow path G2 has a suction-side check valve C1 that allows only the fuel flow from the first fuel chamber F1 to the pump chamber P. Is arranged. Further, a third flow path G3 connected to the pump chamber P and a fourth flow path G4 connected to the third fuel chamber F3 are opened in the second fuel chamber F2, and the third flow path G3 is connected to the third flow path G3 from the pump chamber P. A discharge check valve C2 that allows only the fuel flow to the second fuel chamber F2 is provided.

Further, the third fuel chamber F3 is provided with the fourth flow path G4.
Then, the fifth flow path G5 and the sixth flow path G6 are opened. One end of the fifth flow path G5 opens to the third fuel chamber F3 with the valve seat 8, and the other end faces the outside, and is connected to, for example, a fuel source T or the like. One end of the sixth flow path G6 is open to the third fuel chamber F3, and the other end is connected to a consuming unit Y such as a fuel injection valve. The regulator diaphragm 7 has a valve portion 9 for opening and closing the valve seat 8.
The valve portion 9 is urged toward the valve seat 8 by a regulator spring 10 contracted in the spring chamber S.

Further, the fuel pressure in the third fuel chamber F3 or the sixth flow path G6 is introduced into the pressure accumulating chamber C via the seventh flow path G7.

Next, the operation will be described. When the pulsating pressure generated in the engine is introduced into the pulsating pressure chamber A via the pressure passage A1, the pump diaphragm 3 reciprocates to increase or decrease the chamber volume in the pump chamber P. Increases, the suction-side check valve C1 opens the second flow path G2, and the fuel in the fuel source T flows through the first flow path G1-the first fuel chamber F1-the second flow path G2 into the pump chamber. Inhaled into P. At this time, the discharge-side check valve C2 keeps the third flow path G3 closed. Next, when the chamber volume of the pump chamber P is reduced,
The fuel in the pump chamber P is pressurized, and the discharge-side check valve C2
Opens the third flow path G3, and pressurized fuel in the pump chamber P is supplied to the third fuel chamber F3 via the third flow path G3-the second fuel chamber F2-the fourth flow path G4. You. At this time, the suction side check valve C1 keeps the second flow path G2 closed.

The fuel supplied to the third fuel chamber F3 supplies the fuel whose pressure has been increased to the external consuming section Y via the sixth flow path G6. Here, the third fuel chamber F
When the fuel pressure supplied to the fuel cell 3 rises above a predetermined constant pressure, the regulator diaphragm 7 is displaced toward the spring chamber S according to the pressure rise against the spring force of the regulator spring 10, and is synchronized with the regulator diaphragm 7. The valve part 9 which moves in a suitable manner opens the valve seat 8, and discharges the increased pressure to the outside through the fifth flow path G5.
According to the above, the fuel pressure in the third fuel chamber F3 is again controlled to the predetermined fuel pressure, and the fuel adjusted to the predetermined fuel pressure from the sixth flow path G6 is supplied to the consuming unit Y. Is done. By arranging the damper chamber D facing the first fuel chamber F1 and the second fuel chamber F2, the pulsation of the fuel generated when the pump chamber P operates as a pump can be damped.

Attention is paid here to the pressure accumulating chamber C. When the engine is stopped, the pump chamber P is in a non-driving state, and the pressurized fuel is not supplied to the pressure accumulating chamber C via the seventh flow path G7. According to the above, the pressure accumulation diaphragm 16 is pressed by the pressure accumulation spring 17 and is closest to the pressure accumulation chamber C, and the pressure accumulation diaphragm 16 contacts the accumulation pressure chamber recess 1L. This state is shown in FIG. On the other hand, as described above, when the engine is operated and the pump chamber P performs a pumping operation, and the pressurized fuel is supplied to the third fuel chamber F3, the fuel pressure is increased via the seventh passage G7 to the pressure accumulating chamber C. According to this, the pressure accumulating diaphragm 16 receives the fuel pressure in the pressure accumulating chamber C, is displaced toward the atmosphere chamber E against the spring force of the pressure accumulating spring 17, and the chamber volume of the pressure accumulating chamber C is increased. And the fuel is stored in the pressure accumulating chamber C. Such a state is continuously maintained while the fuel pressure in the third fuel chamber F3 is equal to or higher than a certain pressure value.

In such a negative pressure fuel supply device, the fuel pressure discharged from the pump chamber P may temporarily drop below a certain pressure value. For example, a sudden acceleration operation of the engine corresponds to this, and this is because the pulsating pressure generated in the engine during the rapid acceleration operation temporarily decreases. In such a state, the negative pressure type fuel supply device according to the present invention can suppress the temporary decrease in the pressure, immediately return the fuel pressure to a constant pressure value, and
Can be supplied. That is, from the pump chamber P to the third fuel chamber F
When the fuel pressure supplied to the fuel tank 3 drops below a certain pressure value, the reduced fuel pressure acts on the pressure accumulating chamber C via the seventh flow path G7. According to the above, the pressure accumulation diaphragm 16
Is immediately stored in the pressure accumulating chamber C by the spring force of the pressure accumulating spring 17.
The fuel stored in the pressure accumulating chamber C is pressurized and pressurized, and the pressurized fuel is displaced to the third side through the seventh flow path G7. Acting on the fuel chamber F3, it is possible to suppress a decrease in fuel pressure from the sixth flow path G6 toward the consuming section Y. According to the above description, even if the pressure value of the fuel discharged from the pump chamber P temporarily drops to a certain pressure value or less, the fuel immediately increased in pressure by the accumulator is supplied to, for example, a fuel injection valve as a consuming part. Therefore, the amount of fuel injected from the fuel injection valve does not temporarily decrease, and appropriate fuel can be supplied from the fuel injection valve to the engine, so that good acceleration operation of the engine can be performed. . Although the above description has been given of the case of the acceleration operation of the engine, when the pressure of the fuel discharged from the fuel pump P falls below a certain pressure value for some reason, the fuel pressure is similarly increased toward the certain pressure value. be able to.

Further, according to the negative pressure type fuel supply device of the present invention, in particular, the pump chamber recess 1B forming the pump chamber P of the fuel pump and the pressure accumulating chamber recess 1L forming the pressure accumulating chamber C of the pressure accumulator.
And the third fuel chamber recess 1H forming the third fuel chamber F3 of the pressure control valve are provided in the single pump body 1 in common, the following effects can be achieved. (1) The fuel supply device can be made compact. (2) The number of parts can be reduced and the number of assembling steps can be reduced, so that the manufacturing cost can be greatly reduced. (3) At the time of mounting on the vehicle, only the pump body 1 needs to be mounted on the vehicle by the mounting means, so that the work of mounting on the vehicle is extremely easy. The fuel pump and pressure control valve can be removed.

A third flow path G3 connecting the pump chamber P and the second fuel chamber F2 is disposed above the second flow path G2 connecting the first fuel chamber F1 and the pump chamber P in the direction of gravity. Further, the third fuel chamber F is located above the third flow path G3.
According to the arrangement of the third fuel cell 3, the air bubbles in the first fuel chamber F1, the pump chamber P, and the second fuel chamber F2 which are generated during the pumping operation of the pump chamber P are favorably transferred from the third fuel chamber F3 to the atmosphere. The fuel can be discharged from the flow path G5, thereby achieving an accurate pumping action, and suppressing the incorporation of bubbles into the fuel flowing to the consuming portion Y.

Further, according to the opening of the seventh flow path G7 connected to the third fuel chamber F3 at a position above the pressure accumulating chamber C in the direction of gravity, the air in the pressure accumulating chamber C converges to the position above and at the same time. Since the fuel is discharged to the outside via the seventh flow path G7, the third fuel chamber F3, and the fifth flow path G5, when the pressure accumulating diaphragm 16 compresses the pressure accumulating chamber C, the fuel in the accumulating chamber C is effectively pressurized. it can. If air remains in the pressure accumulating chamber C, the air is compressed, and the pressure in the pressure accumulating chamber C cannot be sufficiently increased.

J1 is a jet disposed in the fourth flow path G4. The jet J1 regulates the fuel pressure from the fourth flow path G4 to the third fuel chamber F3. That is, when the pressure of the fuel flowing in the fourth flow path G4 forms a large pulsating pressure, the jet J1 suppresses the pressure on the positive pressure side, reduces the fluctuation range of the pulsating pressure, and supplies it to the third fuel chamber F3. According to the above, the pulsation of the fuel supplied from the sixth flow path G6 to the consuming portion Y can be reduced, which is suitable for regulating the pressure.

J2 is a jet disposed in the fifth flow path G5, and the jet J2 controls the fuel pressure from the fifth flow path G5 toward the atmosphere. That is, the valve section 9 is
When the valve is opened, the fuel pressure in the third fuel chamber F3 is released from the fifth flow path G5 at a stretch and the pressure in the third fuel chamber F3 is greatly reduced. Since the fuel pressure in F3 is limited and released by the jet J2, the pressure in the third fuel chamber F3 is not greatly reduced, so that the fuel is supplied from the sixth flow path G6 to the consuming unit Y. Fuel pulsation can be reduced. In addition, a jet J1 is arranged in the fourth flow path G4 and a fifth flow path G5
If the jet J2 is disposed at the same position, the above effects can be obtained synergistically.

A fourth flow path G4 connecting the fuel pump function part and the pressure control valve function part and a seventh flow path G7 connecting the pressure control valve function part and the pressure accumulation function part are formed in the pump body 1. In this case, a special connecting pipe is not required, so that the number of parts and the number of assembling steps can be reduced, and the external shape can be simplified without the connecting pipe being exposed to the outside.

In addition, the pressure accumulating spring 17 compressed and contracted in the atmosphere chamber E is a coil spring and a large-diameter large-diameter coil spring 17A, and a small-diameter small-diameter coil spring 17B is disposed in parallel with the coil spring. According to this, the spring constants of these springs can be laid down, whereby the overall height of each of the springs 17A and 17B can be reduced, the depth of the atmosphere chamber E can be reduced, and the overall height of the entire apparatus can be reduced.

[0036]

As described above, according to the first feature of the negative pressure type fuel supply device according to the present invention, when the fuel pressure discharged from the negative pressure pump temporarily decreases, the pressure is immediately increased by the pressure accumulation chamber. Since the supplied fuel is supplied to the consuming unit, an appropriate fuel pressure can be continuously supplied, and thus good operability of the engine can be obtained. In addition, the fuel supply device can be made compact, the manufacturing cost can be reduced, and the maintainability can be greatly improved. As with a motorcycle, the storage space is particularly limited, and the cost for the fuel supply device is greatly reduced. Effective in what is required.

According to the second feature of the present invention, air bubbles in the first fuel chamber, the pump chamber, and the second fuel chamber can be satisfactorily discharged through the third fuel chamber and the fifth flow path. As a result, an accurate pumping operation of the negative pressure pump can be achieved, and a stable fuel supply can be performed.

Further, according to the third feature of the present invention, the pulsating pressure of the fuel from the sixth flow passage toward the consuming portion can be reduced more effectively.

According to the fourth feature of the present invention, the fourth flow path connecting the fuel pump to the pressure control valve and the seventh flow path connecting the pressure control valve to the pressure accumulating chamber are formed in the pump body. Since the fuel supply device is directly exposed to the outside without the need for a separate member such as a pipe and the like, the pipe is not exposed to the outside, it is preferable in improving the appearance of the motorcycle.

Further, according to the fifth aspect of the present invention, since the air in the accumulator can be satisfactorily discharged through the seventh flow path, the pressure can be effectively increased when the accumulator is compressed.

Further, according to the sixth aspect of the present invention, the height in the atmosphere chamber can be reduced, which is effective in making the fuel supply device compact.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a negative pressure type fuel supply device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump main body 2 1st cover 3 Pump diaphragm P Pump chamber F1 1st fuel chamber F2 2nd fuel chamber F3 3rd fuel chamber S Spring chamber 6 4th cover 7 Regulator diaphragm 8 Valve seat 9 Valve part G1 1st channel G2 Second flow path G3 Third flow path G4 Fourth flow path G5 Fifth flow path G6 Sixth flow path G7 Seventh flow path Y Consumption unit T Fuel source C Accumulation chamber E Atmosphere chamber 16 Accumulation diaphragm

Claims (6)

[Claims] A pump diaphragm (3) is sandwiched between a left side surface (1A) of a pump body (1) and a first cover (2) covering the left side surface (1A) of the pump body (3).
To form a pump chamber P, and the pump diaphragm 3
A pulsating pressure chamber A is formed by the left side surface 3B of the pump body 1 and the first cover 2, and a damper diaphragm 5 is sandwiched between the right side surface 1C of the pump body 1 and the second cover 4 covering the same, and the left side of the damper diaphragm 5 A first fuel chamber F1 and a second fuel chamber F2 separated from each other by the surface 5A and the pump body 1 are formed, and the right side surface 5 of the damper diaphragm 5 is formed.
B and the second cover 4 form a damper chamber D. Further, the right side 1C of the pump body 1 and the third cover 15 covering the same hold the pressure accumulating diaphragm 16, and the left side 16A of the pressure accumulating diaphragm 16 and the pump A pressure accumulation chamber C is formed by the main body 1, and an atmosphere chamber E is formed by the right side surface 16 </ b> B of the pressure accumulation diaphragm 16 and the third cover 15.
Furthermore, the upper surface 1G of the pump body 1 and the fourth
The third diaphragm 7 is formed by the lower face 7A of the regulator diaphragm 7 and the pump body 1, and the spring chamber S is formed by the upper face 7B of the regulator diaphragm 7 and the fourth cover 6. And a pressure passage A is formed in the pulsating pressure chamber A.
1, a first flow passage G1 connected to the fuel source T in the first fuel chamber F1, and a suction check valve C1 connected to the pump chamber P at one end.
A second flow path G2 having a discharge side check valve C2 having an end connected to the pump chamber P and connected to the second fuel chamber F2.
The flow path G3 and the fourth flow path G4 connected to the third fuel chamber F3 are opened, and the fifth flow path G5 opened to the third fuel chamber F3 with the fourth flow path G4 and the valve seat 8 and the consuming unit Y are opened. A sixth spring G6 connected to the pressure accumulating chamber C and a seventh passage G7 connected to the pressure accumulating chamber C are opened, and a regulator spring 10 which presses a valve portion 9 which moves synchronously with the regulator diaphragm 7 toward a valve seat 8 in a spring chamber S. And a pressure accumulating spring 17 for pressing the pressure accumulating diaphragm 16 toward the pressure accumulating chamber C in the atmosphere chamber E.
A negative pressure type fuel supply device characterized in that: 2. The apparatus according to claim 1, wherein the third flow path G3 is disposed above the second flow path G2 in the direction of gravity, and the third fuel chamber F3 is disposed further above the third flow path G3. The negative pressure fuel supply device as described in the above. 3. The negative pressure fuel supply device according to claim 1, wherein the jets J1 and J2 are arranged in one or both of the fourth flow path G4 and the fifth flow path G5. 4. The negative pressure type fuel supply device according to claim 1, wherein the fourth flow path G4 and the seventh flow path G7 are formed in the pump body 1. 5. The negative pressure fuel supply device according to claim 1, wherein the seventh flow path G7 is opened at a position above the pressure accumulation chamber C in the direction of gravity. 6. A large-diameter coil spring 1 having a large diameter while using the pressure accumulating spring 17 as a coil spring.
The negative-pressure fuel supply device according to claim 1, wherein the small-diameter coil spring (17B) and the small-diameter coil spring (17B) are arranged in parallel in the atmosphere chamber (E).