JP4243704B2 - Vaporizer plunger type acceleration pump device - Google Patents

Description

  The present invention relates to a carburetor that adjusts and controls the amount and concentration of an air-fuel mixture supplied to an engine, and injects fuel for acceleration into an intake passage that penetrates the carburetor body during rapid acceleration operation of the engine. More particularly, the present invention relates to a plunger type acceleration pump device in which a plunger is slidably disposed in a cylinder hole.

A conventional plunger type acceleration pump device is shown in FIG.
Reference numeral 1 denotes a carburetor body having an intake passage 2 penetrating therethrough, and the intake passage 2 is opened and closed by a throttle valve (not shown).
This throttle valve is a sliding valve attached to the throttle valve shaft and reciprocating linearly in a rotating butterfly valve or sliding valve guide cylinder.
Reference numeral 3 denotes a floating chamber body disposed below the vaporizer body 1, and a floating chamber 4 is formed by the vaporizer body 1 and the floating chamber body 3, and a valve seat and a float (not shown) are formed in the floating chamber 4. A constant oil level XX is formed and held by the cooperative action of the valves.
A cylindrical cylinder hole 5 is formed in the mounting flange 3a above the floating chamber body 3 so as to open, and fuel is sucked from the bottom of the cylinder hole 5 to below the oil level XX of the floating chamber 4. A path 6 is drilled.
A suction-side check valve 7 that allows fuel flow from the float chamber 4 to the cylinder hole 5 is disposed in the fuel suction path.
A fuel discharge path 8 branches from a fuel suction path 6 between the suction side check valve 7 and the cylinder hole 5, and a discharge side check valve 9 is disposed in the fuel discharge path 8. The downstream side of the side check valve 9 opens into the intake passage 2 through the nozzle hole 10 a of the pump nozzle 10.
The guide collar 11 is screwed into the opening 5a above the cylinder hole 5 that opens to the attachment flange 3a of the floating chamber body 3 to close the opening.
The guide collar 11 is provided with a guide hole 11c penetrating from the upper end 11a to the lower end 11b, and a ring-shaped locking groove 11d is provided on the outer periphery in the vicinity of the upper end 11a.
A cylindrical plunger 13 that slides in the vertical direction is movably disposed in the cylinder hole 5, and an operating rod 13 b that is integrally formed with the upper end 13 a of the plunger 13 is provided on the guide collar 11. The guide collar 11 is disposed so as to protrude upward from the upper end 11a of the guide collar 11 through the guide hole 11c.
In addition, the plunger 13 has its upper end 13a abutted against the lower end 11b of the guide collar 11 at its ascent stop position, and its ascent position is limited.
Further, an upper cylinder hole 5 a formed between the lower end 11 b of the guide collar 11 and the upper end 13 a of the plunger 13 is formed below the constant oil level XX of the float chamber 4.
Further, a return passage 12 is opened in the upper cylinder hole, and the other end 12a is opened above the oil level XX of the float chamber 4.
Since the return passage 12 has one end 12b opened in the upper cylinder hole 5a as described above, the one end 12b of the return passage 12 opened in the upper cylinder hole 5a below the oil level XX. .
A rubber cap 14 is formed in a bellows shape by a rubber material, and a lower end 14a thereof is fitted and disposed in a locking groove 11d of the guide collar 11, and an upper end 14b is fitted in an upper outer peripheral portion of the operation rod 13b.
The upper end 14b of the rubber cap 14 moves synchronously with the operating rod 13b, and the lower end 14a is fitted and fixed to the guide collar 11.

When the throttle valve is suddenly opened during the rapid acceleration operation of the engine, the operation lever 15 rotates counterclockwise in FIG. 3 in synchronization with this, and according to this, the operation lever 13b is included. The plunger 13 descends at a high speed in the cylinder hole 5 to compress the lower cylinder hole 5b, and the fuel in the lower cylinder hole 5b facing the lower end 13b of the plunger 13 is pressurized and pump nozzle 10 Accelerating fuel is ejected into the intake passage 2 from the nozzle hole 10a, and the engine is accelerated.
That is, the plunger 13 reciprocates up and down in the cylinder hole 5 in accordance with the opening of the throttle valve. When the plunger 13 is moved upward, the fuel is injected into the cylinder hole 5b below the fuel suction passage 6. And the fuel in the lower cylinder hole 5 a is ejected toward the fuel discharge path 8 and the pump nozzle 10 when the plunger 13 moves downward.

During the operation of the engine, sudden acceleration and deceleration may be repeated continuously in a short time. According to this, the fuel that has entered the cylinder hole 5a above the plunger 13 is sufficiently returned to the return passage 12. Without being able to be discharged further, it gradually accumulates in the upper cylinder hole 5a, and a part of this fuel may overflow from the upper end 11a of the guide collar 11 through the guide hole 11c of the guide collar 11.
Float which, above the cylinder hole 5a is opened upward in the cylinder bore 5a which one end 12b of the return passage 12 is under the oil level X-X is formed in a lower oil level X-X, from the return passage 12 This is attributed to the deterioration of the fuel discharge into the chamber 4, the return passage 12 being blocked by the fuel, and the upper cylinder hole 5 a being in a sealed chamber state.
On the other hand, the fuel overflowing from the upper end 11a of the guide collar 11 is prevented from scattering directly to the outside by the rubber cap 14 arranged around the upper end 11a. In the case where the inner diameter portion expands due to the use over, or the molding accuracy of the rubber cap 14 is poor, the sealing performance of the rubber cap 14 is hindered, and the fuel is discharged from the lower end 14a of the rubber cap 14 to the outside. There is a danger of overflowing towards you.
The rubber cap 14 serves to prevent foreign matter from entering the guide hole 11c and the cylinder hole 5 from the outside.

  The plunger type acceleration pump device according to the present invention is made in view of the above problems, and when the plunger arranged in the cylinder hole is continuously operated, the fuel in the cylinder hole is guided to the guide hole. It is an object of the present invention to provide a plunger type acceleration pump device that rises to the upper end of the guide collar through the nozzle and does not overflow the fuel from the upper end of the guide collar.

In order to achieve the above object, the present invention provides a carburetor body in which an intake passage penetrates and is opened , and the intake passage is opened and closed by a throttle valve, or disposed below the carburetor body, and the carburetor body In addition, a cylinder hole is drilled in the float chamber main body that forms a float chamber that holds the oil level XX inside, and a guide collar is disposed in the opening above the cylinder hole so that it can slide in the cylinder hole. An operating rod formed integrally with the plunger arranged in the cylinder protrudes outward through a guide hole formed in the guide collar, and a return passage toward the float chamber opens in the cylinder hole. ,
On the other hand, the lower end of the bellows-like rubber cap is attached to the upper end outer periphery of the guide collar, in the plunger-type acceleration pump apparatus of the carburetor at the upper end is mounted on the outer periphery of the operating rod projecting upward from the guide collar, the cylinder bore The upper cylinder hole formed between the lower end of the guide collar and the upper end of the plunger is always formed in the oil level XX formed in the float chamber at the plunger ascending stop position and descending stop position. The upper cylinder hole is formed at a higher position, and the upper cylinder hole is always opened in the float chamber above the oil level XX through the return passage.

When the plunger moves from the upper stop position to the lower stop position, the volume of the upper cylinder hole increases, and the fuel in the lower cylinder hole is sucked through the gap between the cylinder hole and the plunger. Although the upper cylinder hole is formed at a position above the oil level, the difference in the fuel intake head can be increased, and the fuel in the lower cylinder hole can be moved into the upper cylinder hole. Is difficult to inhale.
In addition, one end of the return passage that opens into the upper cylinder hole is not blocked by the plunger even when the plunger is in the raised stop position, so that the plunger moves from the raised stop position to the lowered stop position. Thus, even when the volume of the upper cylinder hole is increased, the pressure in the upper cylinder hole can always be kept close to the atmospheric pressure without reducing the pressure.
Therefore, in the acceleration state from the ascending position to the descending position, it is possible to effectively suppress the inflow of fuel into the upper cylinder hole.
Also, since the opening at one end and the opening at the other end of the return passage are both above the oil level and the return passage is always located above the oil level, the return passage is not blocked by the fuel, Even if the fuel enters the upper cylinder hole, it can be immediately discharged into the float chamber, and the fuel does not accumulate or accumulate in the upper cylinder hole.
From the above, even when the engine is accelerating or continuously accelerating, the fuel does not overflow from the upper end of the guide collar.
Further, according to the above, the rubber cap swells and deteriorates due to the overflowing fuel, and the sealing performance is not hindered.

Hereinafter, an embodiment of a plunger type acceleration pump device for a vaporizer according to the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a plunger type acceleration pump device, showing a state where the plunger is stopped.
FIG. 2 is a longitudinal sectional view showing a state where the plunger of FIG. It is.
In addition, about the same component as FIG. 3, the description is abbreviate | omitted using the same code | symbol.
A large-diameter cylinder hole 20a having a diameter larger than that of a plunger, which will be described later, is formed in the carburetor body 1 so as to open toward the mounting flange 3a above the floating chamber body 3. A cylinder hole 20b (which has a diameter slightly larger than the diameter of the plunger and slides and supports the plunger with a minute gap) that opens to face the hole 20a is formed by penetrating vertically.
A guide collar 21 having a guide hole 21a formed therethrough is screwed into the opening 20c above the cylinder hole 20b.
Reference numeral 22 denotes a plunger that is slidably disposed in the cylinder hole 20b formed in the vaporizer main body 1 with a small gap, and is regulated to have a smaller diameter than the cylinder hole 20b and the plunger 22 from the upper end 22a upward. A protrusion 22b is formed to protrude, and an operating rod 22d is formed to protrude upward from the upper end 22c of the restriction protrusion 22b.
The plunger 22 is slidably disposed in the cylinder hole 20b, and the lower end of the plunger 22 is disposed so as to enter the large-diameter cylinder hole 20a and is contracted in the large-diameter cylinder hole 20a. The plunger 22 is biased upward by the provided plunger spring S.
According to this, the raising of the plunger 22 stops at a position where the upper end 22c of the restricting projection 22b contacts the lower end 21b of the guide collar 21. (The state of the plunger 22 is the rising stop position.)
On the other hand, the operating rod 22d protrudes upward through the guide hole 21a of the guide collar 21, and an operating lever similar to that shown in FIG. 3 is arranged facing the upper end of the operating rod 22d. (This control lever is omitted.)
Similarly to FIG. 3, reference numeral 23 denotes a rubber cap having a bellows shape, and its upper end 23 a is mounted on the operating rod 22 d and its lower end 23 b is attached to the outer periphery of the upper end of the guide collar 21.

According to the above , the upper cylinder hole F is formed in the cylinder hole 20b between the lower end 21b of the guide collar 21 and the upper end 22a of the plunger 22.
The upper cylinder hole F is formed above the oil level XX at the ascending stop position (shown in FIG. 1) and the descending stop position (shown in FIG. 2) of the plunger 22.
Further, 24 is a return passage, one end 24a opened to the upper side of the cylinder hole F, the other end 24b is formed to open upward position than the oil level X-X, whereby the return passage 24 is the oil surface X- Placed on X.
Here, in particular, one end 24a of the return passage 24 opens into the upper cylinder hole F. At this time, since the diameter of the restricting projection 22b is smaller than the diameter of the plunger 22, the one end 24a of the return passage 24 is planned. It is not blocked by the jar 22. Therefore, the upper cylinder hole F is always maintained at atmospheric pressure by the return passage 24 regardless of the position of the plunger 22.

Next, the operation will be described.
In the low-opening operation state of the throttle valve, the plunger 22 is in the ascending stop position as shown in FIG. 1. At this time, the plunger 22 is in contact with the lower end 21 b of the guide collar 21 at the upper end 22 c of the restricting projection 22 b. At the most elevated position, air is introduced into the upper cylinder hole F from the opening of one end 24a of the return passage 24, and the atmospheric pressure is maintained.

Next, when the throttle valve is rapidly opened from the above state and the acceleration operation of the engine is performed, the operating rod 22d is pressed by an operating lever (not shown), and the plunger 22 including the operating rod 22d moves downward in the figure. It moves and displaces to the descent stop position state shown in FIG.
According to the above, the fuel in the large-diameter cylinder hole 20a is compressed by the plunger 22, the pressurized fuel is supplied to the fuel discharge path 8 and the pump nozzle 10, and the acceleration fuel is sucked through the injection hole 10a. The engine 2 is injected into the passage 2 so that the engine can be accelerated.

On the other hand, during the acceleration operation, the volume of the upper cylinder hole F increases, thereby reducing the pressure in the cylinder hole F, but one end 24a of the return passage 24 is placed in the upper cylinder hole F. Since the atmosphere is introduced from the opening, the pressure in the cylinder hole F is maintained at atmospheric pressure without decreasing.
According to the above, the fuel in the large-diameter cylinder hole 20a is not sucked into the upper cylinder hole F through the gap between the plunger 22 and the cylinder hole 20b.

Next, when the acceleration operation is finished and the throttle valve is returned to the low opening operation state again, the operation lever (not shown) rotates in synchronization with the throttle valve, and the plunger 22 is the spring force of the plunger spring S. To return to the lift stop position state of FIG. 1 again.
According to the above, as the chamber volume of the large-diameter cylinder hole 20a below the plunger 22 increases, the fuel in the float chamber 4 is sucked into the cylinder hole 20a via the fuel suction passage 6, and the next acceleration operation is performed. Can be provided.
During the upward movement of the plunger 22, the rubber cap 23 is displaced from the contracted state to the extended state, and the chamber volume in the rubber cap 23 increases to generate a negative pressure. This negative pressure is generated in the guide hole 21a. It acts on the upper cylinder hole F via.
Here, paying attention to the upper cylinder hole F, since the upper cylinder hole F is always in communication with the atmosphere via the return passage 24, even if the negative pressure acts on the upper cylinder hole F, the negative pressure is applied. Is discharged to the atmosphere side through the return passage 24, so that the upper cylinder hole F is not kept in a negative pressure state and is always maintained in an atmospheric pressure state.
Therefore, the fuel in the large-diameter cylinder hole 20a is not sucked into the upper cylinder hole F through the gap between the plunger 22 and the cylinder hole 20b.

  In particular, the upper cylinder hole F is always located above the oil level XX at the position where the plunger 22 is raised and lowered, and the openings of the one end 24a and the other end 24b including the return passage 24 are oiled. According to the arrangement above the plane XX, it is difficult for the fuel to flow into the upper cylinder hole F and the return passage 24, and even if the fuel flows into them, it is immediately discharged and the upper cylinder hole F is not cut off from the atmosphere and becomes a sealed chamber.

As described above, according to the plunger type acceleration device of the present invention, in particular, the return passage including the upper cylinder hole and the one end opening of the return passage and the other end opening are all positioned above the oil level formed in the float chamber. When the plunger moves back and forth in the cylinder hole, the fuel in the cylinder hole flows into the upper cylinder hole and goes outward from the upper end of the guide collar. Never overflow.
In addition, since it can be performed simply by selecting the shape and dimensions of the parts included in the conventional plunger type acceleration pump device, that is, the guide collar, the operating rod, and the rubber cap, an increase in manufacturing cost and a vaporizer can be achieved. There is no increase in size.

It is a longitudinal cross-sectional view which shows one Example of the plunger type acceleration pump apparatus of this invention, Comprising: The raise stop position of a plunger is shown. The longitudinal cross-sectional view which shows the descent stop position of the plunger of FIG. It is a longitudinal cross-sectional view of the conventional plunger type acceleration pump apparatus, and shows the raising position of the plunger. The longitudinal cross-sectional view which shows the descent | fall stop position of the plunger of FIG.

Explanation of symbols

4 Float chamber 20b Cylinder hole 21 Guide collar 21b Lower end 22 of guide collar Plunger 22a Upper end 22b of plunger Restriction protrusion F Upper cylinder hole XX Oil level

Claims (1)

An intake passage (2) passes through the inside and is disposed below the carburetor body (1) that is opened or closed by a throttle valve, or the carburetor body (1). The cylinder hole (20b) is drilled in the float chamber body (3) that forms the float chamber (4) that holds the oil level (X)-(X) inside, and an opening above the cylinder hole. A guide collar (21) is disposed on (20c), and an operating rod (22d) formed integrally with a plunger (22) slidably disposed in the cylinder hole (20b) is provided with a guide collar (21). And a return passage (24) toward the float chamber (4) is opened in the cylinder hole (20b) through a guide hole (21a) drilled in
On the other hand, the lower end (23b) of the bellows-like rubber cap (23) is attached to the outer periphery of the upper end of the guide collar (21), and the upper end (23a) of the operating rod (22d) protrudes upward from the guide collar (21). In the plunger type acceleration pump device of the vaporizer mounted on the outer periphery, between the lower end (21b) of the guide collar (21) and the upper end (22a) of the plunger (22) in the cylinder hole (20b) The upper cylinder hole (F) formed in the upper position is always positioned above the oil level (X)-(X) formed in the float chamber (4) at the ascending stop position and the descending stop position of the plunger (22). The plunger of the carburetor is characterized in that the upper cylinder hole is always opened in the float chamber (4) above the oil level (X)-(X) through the return passage (24). Expression Pump device.

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