JPH0754711A - Constant pressure device of constant pressure carburetor for engine - Google Patents

Abstract

PURPOSE:To provide a constant pressure device of a constant pressure type carburetor for engine capable of securely preventing the clogging, by a gasket of the air intake path side opening of a constant pressure connecting path. CONSTITUTION:The air intake path side opening 12a of a constant pressure connecting path 12 which is arranged around the outer periphery of the start end side opening 2a of an air intake path 2 is connected to the purification chamber 4 of an air cleaner 3 through a connecting cylindrical part 14 passed through a gasket 8. Thus the air intake path side opening 12a can not be covered with the gasket 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure equalizing device for a pressure equalizing carburetor of an engine.

[0002]

2. Description of the Related Art As the same pressure device of this type, there is a conventional device shown in FIGS. As shown in FIG. 6, the same-pressure type carburetor (1) for a cutting engine has an air cleaner (3) with a gasket (8) interposed in a start end side opening (2a) of an air intake passage (2) thereof. ), The air purifying chamber (4) is attached in a communicating state, and the terminal side opening (2b) of the air intake passage (2) is, for example, an air cooling side valve engine (4).
And the float chamber (6) communicates with the air suction passage (2) through the same pressure communication passage (7) so that the inside of the float chamber (6) has the same pressure as the air suction passage (2). Is configured.

As clearly shown in FIGS. 6 and 7, the float chamber side opening (7a) of the same pressure communication passage (7).
Is disposed in the vicinity of the side end of the carburetor body, and the air suction passage side opening (7b) of the pressure communication passage (7) has an air suction passage (2) as shown in FIGS. 8 and 9. ) Is formed in the concave surface portion (9) which is recessed rearward with respect to the peripheral wall of the opening (2a) on the starting end side. Gasket (8)
Aligns the vent hole (8a) with the opening portion (2a) on the starting side of the air suction passage (2) so as to hold it between the peripheral wall of the opening (2a) on the starting side and the air purifying chamber (4). Fixed.

[0004]

The opening 7b on the air intake passage side of the same-pressure communication passage 7 is, as shown in FIGS.
A gasket is provided on the concave surface portion 9 which is recessed with respect to the peripheral wall of the opening 2a on the starting end side of the air suction passage 2, and between the peripheral wall of the opening on the starting end side of the air suction passage 2 and the purifying chamber 4 of the air cleaner 3. 8 is interposed. However, the vent hole 8a of the gasket 8 deviates from the normal position which coincides with the air intake passage side opening 7b as shown by the one-dot chain line in FIG. 8, and the air intake passage side opening 7b of the same pressure communication passage 7 is formed. When the gasket 21 covers the front side of the gasket 8, turbulent flow occurs in the back portion of the gasket 8 and negative pressure is generated in the air intake passage-side opening 7b, or the passage cross-sectional area of the front space of the opening 7b is increased. Is smaller and the passage resistance is larger, the float chamber 6
The negative pressure of the liquid becomes large, and it becomes difficult for the liquid fuel (gasoline) in the float chamber 6 to be sucked into the venturi portion 10,
Fuel shortage causes torque drop and output shortage.

Further, for example, an agricultural single wheel type management machine may be operated in a considerably inclined state in a field.
However, as shown in FIG. 7, since the float chamber side opening 7a of the same pressure communication passage 7 is disposed in the vicinity of the side end of the carburetor body, the carburetor body is located on the float chamber side opening 7a side. When the inclination toward the downward slope is large, the opening 7a on the float chamber side is submerged below the liquid surface of the float chamber 6, so that the gasoline in the float chamber 6 passes through the communication passage 7 for equal pressure to the air. The air-fuel ratio of the air-fuel mixture flowing into the intake passage 2 becomes excessive, and harmful incomplete combustion gas is emitted, resulting in a deteriorated exhaust gas / emission state.

Therefore, according to the present invention, it is possible to reliably prevent the air suction passage side opening of the same pressure communication passage from being blocked by the gasket, and to flow the liquid fuel from the same pressure communication passage to the air suction passage even when it is inclined. The technical problem is to prevent the above as much as possible.

[0007]

The present invention is characterized in that the same pressure device of the same pressure type carburetor of an engine is configured as follows as a technical means for achieving the above-mentioned problems. Invention 1. (See FIGS. 1 to 3) Outside the peripheral edge of the opening 2a on the starting end side of the air suction passage 2, the opening 12a on the air suction passage side of the communication passage 12 for the same pressure is
The air purifying chamber 4 of the air cleaner 3 is communicated with the communication cylinder portion 14 and the communication cylinder portion 14 is penetrated through the gasket 8.

Invention 2. (See FIGS. 4 and 5) In the same pressure device for the same pressure type carburetor for an engine according to the first aspect of the invention, a communication hole 17 is used instead of the communication cylinder portion 14, and the communication hole 17 is used for the air suction passage 2 Open the choke valve shaft 16a of the choke valve 16 in the
7, the air suction passage side opening 1 of the same pressure communication passage 15
5a is connected to the air suction passage 2.

Invention 3. (See FIGS. 1, 2, and 4) In the same pressure device for the same pressure type carburetor for an engine according to the first or second aspect of the invention, the float chamber side openings 12b and 15b of the same pressure communication passages 12 and 15 are provided. On the upper surface of the float chamber 6 near the center near the main nozzle 13.

[0010]

[Action]

Invention 1. (See FIGS. 1 to 3) When installing the air cleaner 3, the air suction passage 2
Of the same pressure communication passage 1 arranged outside the peripheral edge of the opening 2a on the starting end side of the
The air suction passage side opening 12a of No. 2 is communicated with the air purifying chamber 4 of the air cleaner 3 through the communication cylinder portion 14 in a positioning state in which the communication cylinder portion 14 is penetrated with respect to the gasket 8. A part of the front side of the air suction passage side opening 12a of the passage 12 is not covered with the gasket 8, and the same pressure communication passage 12 is correctly communicated with the air suction passage 2 through the air purification chamber 4 of the air cleaner 3. Therefore, the internal pressure of the float chamber can always be kept constant at a predetermined value.

Invention 2. (See FIGS. 4 and 5) The air suction passage side opening 15a of the same pressure communication passage 15 is connected to the air suction passage 2 through the communication hole 17 formed in the choke valve shaft 16a of the choke valve 16 separated from the gasket 8. Since they communicate with each other, the gasket 8 does not block the inlet side of the air intake passage-side opening 15a. Moreover, since the communication hole 17 is formed in the choke valve shaft 16a of the choke valve 16, the same pressure communication passage 15 formed in the carburetor main body is formed.
Can be formed by simple processing.

Invention 3. (See FIGS. 1, 2, and 4) Float chamber side opening 12b of the same pressure communication passages 12,15.
15b is the main nozzle 13 on the upper surface of the float chamber 6.
Since the opening is in the central portion close to, the float chamber side openings 12b and 15b have almost no fluctuation in the liquid level height at the position below the carburetor 1 in any direction. Therefore, the liquid fuel is not immersed in the liquid, and the liquid fuel does not flow out to the air intake passage 2 through the same pressure communication passages 12 and 15. Therefore, the tilt allowable angle at the time of tilting the engine can be set to a large value, and the tilting performance is significantly improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Example 1. (See FIGS. 1 to 3) FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a partially cutaway bottom view of the carburetor main body, and FIG. 3 is a left side view of the same pressure type carburetor 1. 6 and 8 showing the prior art in these figures, the same or equivalent parts are designated by the same reference numerals, and the description thereof will be omitted. Differences from those in FIGS. 6 to 8 are as follows. The air suction passage side opening 12a of the same pressure communication passage 12 is formed in a concave shape as shown in FIGS. 1 and 2 at a position outside the peripheral edge of the starting end side opening 2a of the air suction passage 2 as shown in FIG. In addition, the float chamber side opening 12b of the same pressure communication passage 12 is
The float chamber 6 as shown in FIGS. 1 and 2 respectively.
It is arranged on the upper surface near the center near the main nozzle 13, and on the other hand, it is fitted into the recess of the air suction passage side opening 12a of the same pressure communication passage 12 from the purifying chamber 4 of the air cleaner 3 so as to communicate therewith. Only the configuration is such that the communication cylinder portion 14 is provided in a protruding manner, and the gasket 8 is provided with the insertion hole 8b of the communication cylinder portion 14.

Therefore, when the air cleaner 3 is attached, the air cleaner is attached to the opening 12a on the air intake passage side of the same-pressure communication passage 12 which is arranged in a concave shape outside the opening 2a on the starting end side of the air intake passage 2. 3 communication cylinder part 1
Since 4 is inserted into the insertion hole 8b of the gasket 8 in a positioned state, the air suction passage side opening 12a of the same pressure communication passage 12 is completely blocked by the gasket 8 at a part of the front side. At the same time, the air suction passage 2 is surely communicated with the air cleaner 3 through the air purification chamber 4 of the air cleaner 3, so that the internal pressure of the float chamber 6 can be always kept constant.

The opening 12b on the float chamber side of the same pressure communication passage 12 is located on the upper surface of the float chamber 6 and is the main nozzle 1.
Since the float chamber side opening 12b is disposed in the central portion close to 1, the liquid level below the float chamber side opening 12b is equal to that of the carburetor 1.
Since there is almost no change with respect to the inclination in any direction of 1, the liquid fuel is not immersed in the liquid, and the liquid fuel does not flow out to the air intake passage 2 through the same pressure communication passage 12. Therefore, it is possible to set a large allowable tilt angle during the tilt operation of the engine, so that the tilt operation performance is significantly improved.

Example 2. (Refer to FIG. 4 and FIG. 5) FIG. 4 is a longitudinal sectional view of an essential part of Embodiment 2 of the present invention, and FIG. 5 is a left side view thereof. In these figures, the same or equivalent parts as those in FIGS. 1 to 3 are designated by the same reference numerals and the description thereof will be omitted. The structure in which the float chamber side opening 15b of the same pressure communication passage 15 is arranged in the float chamber 6 near the center of the main nozzle 13 is similar to that of the first embodiment. The difference from the first embodiment is that a communication hole 17 is formed in the choke valve shaft 16 of the choke valve 16 and one end opening of this communication hole 17 communicates with the air intake passage side opening 15a of the same pressure communication passage 16. It is the only configuration.

Therefore, also in the second embodiment, the other end opening of the communication hole 17 communicating with the air intake passage side opening 15a is formed in the valve valve shaft 16 of the choke valve 16 separated from the gasket 8. Does not block part of it. The opening 15b on the float chamber side of the same pressure communication passage 15 has the main nozzle 1 in the float chamber 6.
The same effect as in the first embodiment is obtained in that the tilting operation performance is remarkably improved by being arranged in the central portion close to 3. When the float chamber side opening 15b of the same pressure communication passage 15 is arranged in the vicinity of the center of the upper surface of the float chamber 6, the air suction passage side opening 15a is arranged at the choke valve 16 position. Although it may be difficult to perform the complicated processing due to the relationship with the installation position, in the second embodiment, the choke valve 16 is used.
Since the communication hole 17 is formed in itself, the same-pressure communication passage 15 formed in the carburetor main body can be formed simply by performing a simple process, and a problem such as an increase in the number of steps does not occur.

[0018]

As described above, according to the same pressure device of the same pressure type carburetor for an engine of the present invention, the following effects can be obtained. Invention 1. The air intake passage side opening of the same-pressure communication passage arranged outside the periphery of the opening end side opening portion of the air intake passage is passed through the gasket to form the air cleaner's air purifying chamber through the communication cylinder. When the air cleaner is attached, the front part of the air suction passage side opening of the same pressure communication passage is not covered with the gasket when the air cleaner is attached, and the float chamber is cleaned for the same pressure communication passage and the air cleaner. It is possible to always communicate properly with the air intake passage through the air chamber, and it is possible to always maintain the float chamber pressure at a proper value and maintain the mixture ratio properly.

Invention 2. Further, since the air suction passage side opening of the same pressure communication passage is communicated with the communication hole formed in the choke valve shaft of the choke valve that is separated from the gasket, the gasket closes the front side of the air suction passage side opening. Never. Moreover, since the communication hole is formed in the choke valve shaft of the choke valve, the same-pressure communication passage formed in the carburetor body can be formed by simple processing.

Invention 3. Further, since the float chamber side opening of the same pressure communication passage is arranged in a portion near the center on the upper surface of the float chamber near the main nozzle, the float chamber side opening is no matter which direction the carburetor is inclined, Since the liquid level at the lower position of this does not change much, it is not immersed in the liquid and liquid fuel does not flow out into the air intake passage through the same pressure communication passage.
The tilt allowable angle at the time of tilt operation of the engine can be set to a large value, and tilt operation performance is significantly improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is a partially cutaway bottom view of the carburetor main body.

FIG. 3 is a left side view of the same.

FIG. 4 is a vertical cross-sectional view of the essential parts of Embodiment 2 of the present invention.

FIG. 5 is a left side view of the same.

FIG. 6 is a vertical sectional view of a conventional technique.

FIG. 7 is a partially cutaway bottom view of the carburetor main body.

FIG. 8 is a left side view of the same.

FIG. 9 is a perspective view of the main part of the same.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Same-pressure type carburetor, 2 ... Air suction passage, 2a ... 2 opening end side opening part, 3 ... Air cleaner, 4 ... Purification chamber, 6 ... Float chamber, 8 ... Gasket, 12 ... Same pressure communication passage, 12a
... 12 air intake passage side openings, 12b ... 12 float chamber side openings, 13 ... main nozzles, 14 ... communication cylinders,
15 ... Communication passage for equal pressure, 15a ... 15 air intake passage side opening, 15b ... 15 float chamber side opening, 16 ... Choke valve, 16a ... Choke valve shaft, 17 ... Communication hole.

Claims (3)

[Claims] 1. A float chamber (6) of a constant pressure vaporizer (1).
Is communicated with the air intake passage (2) through the same pressure communication passage (12) so that the inside of the float chamber (6) has the same pressure as the inside of the air intake passage (2). ), The air cleaner (3) is attached to the opening (2a) of the start end side of the engine (2) so as to be in communication with the gasket (8) sandwiched between the air cleaner (3) and the air intake passage (2). Outside the periphery of the opening (2a) on the starting end side of the air cleaner, the opening (12a) on the air intake passage side of the communication passage (12) for equal pressure is cleaned by the air cleaner (3) via the communication cylinder (14). It communicates with the chamber (4), and this communication cylinder (1
4) A pressure equalizing device for an equal pressure type carburetor for an engine, characterized in that the gasket (8) is penetrated. 2. The pressure equalizing device for an equal pressure type carburetor for an engine according to claim 1, wherein a communication hole (17) is used instead of the communication cylinder portion (14), and the communication hole (17) is Open the choke valve shaft (16a) of the choke valve (16) in the air intake passage (2),
An equal pressure type vaporization of an engine, characterized in that the air suction passage side opening (15a) of the same pressure communication passage (15) is made to communicate with the air suction passage (2) through this communication hole (17). Pressure device of the vessel. 3. The float chamber side openings (12b) (15b) of the same pressure communication passages (12) (15) are located in the upper surface of the float chamber (6) near the center near the main nozzle (13). Claim 1 or Claim 2 formed by opening
The same pressure device of the same pressure type carburetor of the engine according to.