JP2000080959A - Constant vacuum sliding throttle valve carburetor - Google Patents

Abstract

(57) [Problem] To make the movement of the tip of a forced operation lever driven by a throttle valve operating lever and the movement of the tip of a driven lever engaged with a sliding throttle valve the same. SOLUTION: A negative pressure chamber 14 is defined above a film 5 sandwiched between an upper end wall of a vaporizer main body 6 and an upper cover 4, and an atmosphere chamber 13 is defined below. A sliding throttle valve 26 coupled to the membrane 5 is supported in the guide opening 17 orthogonal to the intake passage 33 of the carburetor body 6 so as to be able to move up and down. The rotary shaft 7 for connecting the throttle valve operating lever 56 is disposed in the atmosphere chamber 13, and the driven lever 8 supported by the rotary shaft 7 to be freely rotatable is provided with a throttle valve operating lever according to the opening degree of the sliding throttle valve 26. Forced operation lever 58 to be disengaged from 56
Is axially supported by a throttle valve operating lever 56. Driven lever 8
Is engaged with the pin 25 of the wall plate 22 on the side of the sliding throttle valve 26. The membrane 5 and the holding plate 10 are overlapped on the upper surface of the upper end flange 26a, and the reinforcing plate 50 integral with the wall plate 22 is overlapped on the lower surface and fastened by bolts 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable bench lily carburetor mounted on an internal combustion engine such as a two-wheeled vehicle, and more particularly, to a negative pressure responsive sliding throttle valve for controlling a bench lily area according to an air flow rate in an intake passage. Is driven by a throttle valve operating lever disposed in an atmosphere chamber of a carburetor main body.

[0002]

2. Description of the Related Art In a constant vacuum sliding throttle valve type carburetor according to Japanese Patent Application No. 9-220955 filed by the present applicant, an upper cover is connected to a top end wall of a carburetor body with a circular film interposed therebetween. A negative pressure chamber is defined above the membrane, and an atmosphere chamber is defined below the membrane. The upper end of a sliding throttle valve that is inserted into a guide opening orthogonal to the intake path of the carburetor so as to be able to move up and down is connected to the membrane. A pressure switching valve driven by a throttle valve operating lever is supported inside the sliding throttle valve so as to be able to move up and down, and the pressure switching valve introduces a negative pressure in the intake passage or the atmosphere into the negative pressure chamber to slide the throttle. The opening of the valve is controlled.

In the above-described constant-vacuum sliding throttle valve carburetor, the pressure switching valve is switched in relation to the operation of the sliding throttle valve. For example, in the acceleration operation of the engine, the negative pressure passage is opened and the atmosphere passage is closed to introduce the intake negative pressure in the intake passage into the negative pressure chamber. Conversely, during the deceleration operation of the engine, the negative pressure passage is closed and the atmospheric passage is open.

Accordingly, the valve body and the valve seat of the four pressure switching valves are present in the negative pressure passage and the atmospheric passage, and air leaks due to the adhesion of foreign substances to the valve seat and changes with time occur. It will be easier. In order to accommodate the valve bodies and valve seats of as many as four pressure switching valves inside the sliding throttle valve, it is necessary to reduce the size of each member, and the passage area of the negative pressure passage is also restricted.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to move the tip of a forced operation lever driven by a throttle valve operation lever in a forced operation range of a sliding throttle valve, and
It is an object of the present invention to provide a constant-vacuum sliding throttle valve carburetor in which the movement of the tip of a driven lever engaged with the sliding throttle valve is made the same.

Another object of the present invention is to provide a constant-vacuum sliding throttle in which an interlocking mechanism between a sliding throttle valve and a driven lever is integrally formed with a reinforcing plate sandwiched between an upper end flange of the sliding throttle valve and a film. It is to provide a valve type vaporizer.

Another object of the present invention is to provide a constant-vacuum sliding throttle valve carburetor in which the attitude of the fuel metering needle valve with respect to the sliding throttle valve does not change due to fluctuations in the intake negative pressure. .

Another object of the present invention is to provide a constant-vacuum sliding throttle valve vaporizer which can selectively engage a stopper piece of a remote control cable with a throttle valve operating lever.

[0009]

In order to solve the above-mentioned problems, a configuration of the present invention is to provide a negative pressure chamber above a membrane sandwiched between an upper end wall of a vaporizer main body and an upper cover, and a lower pressure chamber below the membrane. A throttle valve operating lever for controlling a degree of opening of the sliding throttle valve by supporting a sliding throttle valve coupled to the membrane in a guide opening orthogonal to the intake path of the carburetor body so as to be able to move up and down. A forcible for disposing a driven lever freely rotatably supported on the rotating shaft in accordance with the opening degree of the sliding throttle valve with respect to the throttle valve operating lever by disposing a rotating shaft for coupling In a constant-vacuum sliding throttle valve type carburetor in which an operating lever is axially supported by the throttle valve operating lever, a wall plate in which a notch provided at the tip of the driven lever is disposed parallel to a side wall surface of the sliding throttle valve. Of the upper end flange, and the reinforcing plate on the lower surface. Overlapping each combined, screwed bolt extending through the upper flange and the holding plate to the reinforcing plate, characterized in that the wall plate is formed integrally with the reinforcing plate.

In the structure of the present invention, the reinforcing plate having the wall plate and the valve plate of the sliding throttle valve may be integrally formed, or the reinforcing plate and the valve plate of the sliding throttle valve may be formed separately. Then, a holding plate sandwiching the film and an upper end flange of the sliding throttle valve are fastened to the reinforcing plate by bolts, and a slit of the valve plate is engaged with a protruding edge of the reinforcing plate.

Further, in the structure of the present invention, the hole through which the fuel metering needle valve of the sliding throttle valve is inserted and supported is formed as a negative pressure passage for guiding the intake negative pressure of the intake passage to the negative pressure chamber. The base flange is pressed against the inclined surface formed at the bottom of the cylindrical portion provided inside the valve by the force of a spring interposed between the upper cover and the base flange of the fuel metering needle valve,
The tip of the fuel metering needle valve is inserted into the high-speed fuel supply nozzle while being inclined to the downstream side of the intake passage, and abuts on the inner peripheral surface of the high-speed fuel supply nozzle.

Further, in the configuration of the present invention, a stopper piece extending in a direction perpendicular to the remote control cable at an end of the remote control cable connecting the acceleration lever and the operating member connected to the outer end of the rotating shaft is provided. The acceleration lever is provided with a hole for selectively engaging one of the remote control cable and the retaining piece extending in the same direction.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a forcible operating lever is supported by a throttle valve operating lever. The forcibly operated lever is a driven lever that is freely rotatably supported on the rotation axis of the throttle valve operating lever, and is constrained in the low opening range of the sliding throttle valve, and the tip of the throttle valve operating lever and the driven lever move in the same way. And release outside the low opening range.

At the time of deceleration operation of the sliding throttle valve, the throttle valve operating lever pushes the driven lever in the closing direction, and the on-off valve is opened by the negative pressure in the negative pressure chamber, and the atmosphere in the atmosphere chamber enters the negative pressure chamber. The negative pressure chamber is instantaneously brought to the atmospheric pressure, and no force acts to prevent the sliding throttle valve from returning during deceleration operation.

The driven lever is connected to the sliding throttle valve by a pin engaged with a notch at the tip of the driven lever.
The pin is supported on a wall plate integral with a reinforcing plate coupled to the upper flange of the sliding throttle valve together with the membrane and the holding plate. The valve plate of the sliding throttle valve can also be formed integrally with the reinforcing plate.

[0016]

1 is a side sectional view of a sliding throttle valve carburetor according to the present invention, and FIG. 2 is a plan sectional view of the sliding throttle valve carburetor. The sliding throttle valve type carburetor according to the present invention comprises a carburetor body 6.
A guide opening 17 having a rectangular cross section orthogonal to the intake passage 33 is provided above the intake passage 33 that penetrates the intake passage 33, and a pair of left and right guide grooves 20 is provided at a front end (a downstream end of the intake passage 33) of the guide opening 17. A valve plate 2 provided with a sliding throttle valve 26 having a rectangular cross section is connected to the guide opening 17 and to the front wall surface of the sliding throttle valve 26.
2 are fitted into the guide grooves 20 so as to be able to move up and down. A bowl-shaped atmosphere chamber 13 is formed at an upper end of the carburetor body 6, and a bottom portion of the atmosphere chamber 13 passes through a cylindrical portion 9 of the intake path 33 at a rear end (upstream end of the intake path 33). Part). An air cleaner (not shown) is connected to the cylindrical portion 9. A high-speed fuel supply nozzle 30, a low-speed fuel passage 38, a starting fuel passage represented by a bleed pipe 35a, and an accelerating fuel passage 34 are provided below the carburetor body 6. These protrude into a float type fuel storage tank (not shown) connected to the carburetor body 6.

A bowl-shaped upper cover 4 made of a synthetic resin or the like is connected to the upper end of the vaporizer main body 6 so as to sandwich the periphery of the circular film 5. A negative pressure chamber 14 is defined above the membrane 5, and an atmosphere chamber 13 is defined below the membrane 5. The holding plate 10 is superimposed on the upper surface of the membrane 5, and the upper end flange 26a of the sliding throttle valve 26 and the metal reinforcing plate 50 are superimposed on the lower surface of the membrane 5, and are connected to each other by a plurality of bolts 41 (FIG. 9). Is done. A cylindrical portion 24 communicating with the negative pressure chamber 14 is formed near the center of the holding plate 10, the membrane 5, and the sliding throttle valve 26.

In order to cast out the supporting portion of the rotary shaft 7 of the throttle valve operating lever 56 in the carburetor body 6, the center of the circular membrane 5 is positioned with respect to the high-speed fuel supply nozzle 30 on the side of the air purifier (the intake passage 3).
3) (upstream of 3). As a result, the mounting portion of the throttle valve operating lever 56 is widened, the distance between the center of the sliding throttle valve 26 and the rotating shaft 7 and the throttle valve operating lever 5
The degree of freedom of design for the shape 6 and the like is increased, and the assembling is facilitated.

An air funnel 54 is inserted into the cylindrical portion 9 of the vaporizer main body 6, and the tip of the air funnel 54 is locked to the cylindrical portion 9. That is, a plurality of cut-and-raised pieces 55 bent outward from the tip of the air funnel 54 are
It is locked in a groove 47 provided in the cylindrical portion 9.

For the convenience of die casting, the first and second insertion grooves 63 and 43 orthogonal to the intake path 33 are provided in the carburetor body 6.
Then, the first and second inserts 65 and 45 are engaged from the atmosphere chamber 13. That is, the wedge-shaped first insert 65 is engaged with the first insertion groove 63, and the block-shaped second insert 45 is engaged with the second insertion groove 43. In the first and second insertion grooves 63, 43, an intake path that is continuous with the intake path 33 of the carburetor body 6 is formed.

As shown in FIGS.
a air hole 16 connecting the negative pressure chamber 14 and the air chamber 13 provided in
The stem 15b of the on-off valve 15 is inserted so as to be able to move up and down. A soft valve body 15 is provided on the lower surface of the upper end flange of the on-off valve 15.
The spring 19 is interposed between the lower surface of the upper end flange 26a of the sliding throttle valve 26 and the spring seat 18 locked to the lower end of the stem 15b of the on-off valve 15.

As shown in FIGS. 6 and 7, the on-off valve 15 is supported so that the stem 15b can be raised and lowered in a through hole 16a formed in the upper end flange 26a. 4 around the through hole 16a
One air hole 16 is formed. A cylindrical valve seat 16b is provided on the holding plate 10 from the upper end flange 26a.
1 protruded into the inside of the valve body and connected to the lower surface of the on-off valve 15
When 5a is pressed against the valve seat 16b by the force of the spring 19, the air hole 16 is closed. However, sliding throttle valve 2
6, the stem 15b hits the carburetor body 6, more specifically the second insert 45, and the on-off valve 15 is
b.

As shown in FIG. 1, an inclined surface 24a (FIG. 3) for supporting a spring seat 27 connected to the upper end of a fuel metering needle valve 29 is formed at the bottom of the cylindrical portion 24 of the sliding throttle valve 26. You. A through hole 26b into which the fuel metering needle valve 29 is inserted and a plurality of axial grooves 26c are formed below the inclined surface 24a of the sliding throttle valve 26. The spring 3 is interposed between the spring seat 27 and the upper cover 4. Buckling of the upper half of the spring 3 is suppressed by the guide rod 2 projecting from the upper cover 4. The fuel metering needle valve 29 is inserted into the high-speed fuel supply nozzle 30 through the through hole 26b, and is pressed against the front peripheral wall surface of the cylindrical portion of the high-speed fuel supply nozzle 30 (downstream of the intake passage 33). Fluctuation in fuel amount due to wobble of the valve 29 is suppressed.

As shown in FIG. 2, the left and right 1
The valve plate 22 guided on both sides by the pair of guide grooves 20 is formed of a metal plate. The inverted conical tip of the rivet 48 fixed to the lower end in advance is provided on the front surface of the synthetic resin sliding throttle valve 26. The horizontal V-groove formed at the upper end of the valve plate 22 is engaged with the vertical trapezoidal groove 49 provided in the vertical direction.
Is engaged with the protruding edge 50b having a V-shaped cross section.

In the embodiment shown in FIG. 4, the valve plate 22 is formed at its upper end with an elongated transverse slit 22a. The slit 22a is a triangular protruding edge 50 of a U-shaped reinforcing plate 50.
b. The reinforcing plate 50 is screwed with a bolt 41 shown in FIG.
And the upper end flange 26a and the reinforcing plate 50 are connected to each other. The pin 25 is supported by a wall plate 50a extending downward from one side edge of the reinforcing plate 50. As shown in FIG. 5, the valve plate 22 and the wall plate 50a are integrally formed, and the valve plate 22 is
May be superimposed on the front wall of the vehicle and connected by bolts.

As shown in FIG. 1, the cylindrical portion 35 projecting downward from the carburetor body 6 is inserted into a fuel storage tank (not shown) connected to the lower end of the carburetor body 6. Many through holes 3
0a is provided at the upper end of the intake passage 3
3 and a lower end portion thereof is projected into the cylindrical portion 35. A passage 31 extending rearward from the inside of the cylindrical portion 35 and communicating with the cylindrical portion 9 is formed in a lower wall portion of the carburetor body 6, and an air jet 32 is fitted to an end of the passage 31.

A rotating shaft 7 is rotatably supported by a boss 6a inside the atmosphere chamber 13 on the rear wall of the vaporizer main body 6. As shown in FIG. 2 and FIG.
The throttle valve operating lever 56 is externally fitted to the deformed shaft portion 7b at the inner end of the rotating shaft 7, is fixed by the bolt 23, and the driven lever 8 is supported to be freely rotatable.

As shown in FIG. 8, a pin 25 of a wall plate 50a extending downward from a side edge of the reinforcing plate 50 is engaged with a notch 8b formed at the tip of the driven lever 8. A forcible operation lever 58 composed of a bell crank is supported by a shaft 57 on the arm 56 b of the forked valve operation lever 56. Axis 57
The forcible operation lever 58 is urged to rotate clockwise in FIG. Between the idle position of the throttle valve operating lever 56 and the set opening,
The protrusion 8a protruding laterally from the driven lever 8 includes an arm 56a of the throttle valve operating lever 56 and an arm 58 of the forcibly operating lever 58.
a, the driven lever 8 is the throttle valve operating lever 5
6 forcibly rotates in the forward and reverse directions.

As shown in FIG. 1, the first insertion groove 63 is provided on the side wall downstream of the sliding throttle valve 26 of the carburetor body 6, and is connected to the first inserting groove 63 by the valve of the sliding throttle valve 26. A first insert 65 made of the same material as the vaporizer main body 6 is inserted from the upper side so as to be in contact with the front surface of the plate 22, and is coupled to the vaporizer main body 6. The bi-starter 44 is formed in the first insert 65. The bistarter 44 inserts a plunger 66 into a cylinder 64 provided on a first insertion body 65 and
The rod connected to 6 protrudes out of the vaporizer body 6,
And the start button 70 (FIG. 2) is connected. The outer end of the rod is covered by bellows 72. The starting fuel passage 68 extending from the bleed tube 35a of the cylindrical portion 35 is
4 to the end. A starting air passage opening to the atmosphere chamber 13 across the cylinder 64 and a starting fuel passage opening to the intake passage 33 are provided. When the engine start operation is performed, when the start button 70 is pulled outward, the start air passage and the start fuel passage communicate with the cylinder 64, and the fuel from the start fuel passage 68 and the air from the start air passage pass through the cylinder 64. The mixed and rich mixture is supplied to the intake path 33. The configuration of the bi-starter 44 is not directly related to the gist of the present invention and will not be described further.

As shown in FIG. 2, an acceleration pump 73 is formed in the second insert 45. The acceleration pump 73 inserts a piston 75 into a cylinder 74 formed in the second insert 45 to partition a pump chamber 76, and moves the piston 75 to the rotating shaft 7 by the force of a spring 77 housed in the pump chamber 76. The pump chamber 76 is connected to the acceleration fuel passage 34 (FIG. 1) via a not-shown passage by engaging with the formed notch cam 7a. The acceleration fuel passage 34 communicates with the inner space of the high-speed fuel supply nozzle 30 via the passage 37a, the annular groove 37 of the high-speed fuel supply nozzle 30, and the passage 37b. High-speed fuel supply nozzle 3
A screw 39 having a fuel jet 40 is screwed into the lower end of the zero.

As shown in FIGS. 10 and 11, an acceleration lever 91 is connected to the outer end of the rotating shaft 7, and is interlocked with and connected to an operation member attached to the portable work machine by a remote operation cable 97. An auxiliary plate 92 is connected to the peripheral edge of the acceleration lever 91 formed of a fan-shaped plate. The distance between the peripheral edge of the auxiliary plate 92 and the peripheral edge of the acceleration lever 91 is set so that the remote control cable 97 can be inserted. I have. The space between the auxiliary plate 92 and the acceleration lever 91 is wider on the axial center side than the peripheral edge, and a hole 93 through which the retaining piece 94 is inserted is provided. The hole 93 has a radial slit 95 through which the remote control cable 97 can be inserted.
Connected to Accordingly, the retaining piece 9 extending vertically from the remote control cable 97 of the terminal of the remote control cable 97.
4 is inserted into the hole 93 from a direction perpendicular to the plate surface of the acceleration lever 91, and the remote control cable 97 is connected to the slit 9.
When the cable 5 is inserted into the groove 98 between the acceleration lever 91 and the auxiliary plate 92, the remote control cable 97 is guided while being wound around the groove 98. When the remote control cable 97 is pulled in the direction of the arrow x in FIG. 10, the acceleration lever 91 rotates clockwise together with the rotation shaft 7, the opening of the sliding throttle valve 26 increases, and Accelerated.

When the axial stopper piece 96 is locked to the end of the remote control cable 97, the distance between the acceleration lever 91 and the auxiliary plate 92 shown in FIG. To the hole 99. The remote control cable 97 is guided into the narrow groove 98 as shown in FIG. 13, and the retaining piece 96 is locked in the step 90 between the hole 99 and the groove 98 shown in FIG.

Next, the operation of the sliding throttle valve type carburetor according to the present invention will be described. Prior to the start of the engine, when the start button 70 is pulled to the right by hand and released in FIG. 2, the fuel in the bleed tube 35a passes through the start fuel passage 68 to the cylinder 6
4, the air in the atmosphere chamber 13 enters the cylinder 64, and the two are mixed and supplied from the cylinder 64 to the intake passage 33. Thus, when the bi-starter 44 is in the operating state, the engine can be started. When the sliding throttle valve 26 is in the idle position shown in FIG. 1, the forcibly operating lever 58 supported by the throttle valve operating lever 56 shown in FIG. 8 protrusions 8
a is sandwiched between the arm 56a of the throttle valve operation lever 56 and the arm 58a of the forced operation lever 58. The air flowing in the upper part of the intake passage 33 in the direction of arrow x (FIG. 1)
6, but eventually hits the valve plate 22 and passes under the valve plate 22. At this time, the high-speed fuel supply nozzle 3
Zero fuel is sucked and supplied to the engine while mixing with air.

When the throttle valve operating lever 56 of the rotary shaft 7 is rotated clockwise in FIGS. 1 and 8 by the acceleration lever 91 during the acceleration operation of the engine, the driven lever 8 is integrally formed with the throttle valve operating lever 56. 8 from the position shown in FIG. 8 to the position shown in FIG. When the throttle valve operating lever 56 rotates by a set angle (set opening of the sliding throttle valve 26), the forced operating lever 58
Of the release pin 61 fixed to the carburetor body 6
, The arm 58a of the forced operation lever 58 is separated from the projection 8a.

As shown in FIGS. 14 and 15, during the rapid acceleration operation of the engine, the forced operation lever 58 forcibly pushes the sliding throttle valve 26 up to the set opening regardless of the negative pressure in the intake passage 33, and the film is moved. 5 is pushed up by about half a stroke. At this time, since the on-off valve 15 is open, it does not exert a drag on the acceleration operation of the throttle valve operation lever 56. When the throttle valve operating lever 56 of the rotating shaft 7 is further rotated clockwise (acceleration direction) in FIG. 1 by the acceleration lever 91, the on-off valve 15 closes, and the arm 58b of the forcibly operating lever 58 shown in FIG. The arm 58a separates from the protruding portion 8a at 61. Intake path 3
3 acts on the negative pressure chamber 14 through the groove 26c of the sliding throttle valve 26 (FIG. 3) and the cylindrical portion 24, and together with the film 5 due to the pressure difference between the negative pressure chamber 14 and the atmosphere chamber 13. Sliding throttle valve 26
The fuel metering needle valve 29 is sucked up. At the same time as the amount of air passing through the intake passage 33 increases, the amount of fuel sucked into the intake passage 33 from the fuel storage tank via the high-speed fuel supply nozzle 30 increases. Following the clockwise rotation of the throttle valve operating lever 56, the driven lever 8 that engages with the pin 25 of the wall plate 50a of the sliding throttle valve 26 rotates clockwise, and the protrusion of the driven lever 8 protrudes. 8a is in contact with the arm 56a of the throttle valve operating lever 56.

As described above, when the throttle valve operating lever 56 is accelerated from the idle position, the sliding throttle valve 26 is quickly opened to the set opening, and then the opening and closing valve 15 is used to open the atmosphere hole 1.
6 is closed, the opening degree of the sliding throttle valve 26 becomes
As shown by the line A, the pressure increases rapidly according to the strength of the intake negative pressure in the intake passage 33, and a smooth acceleration operation of the engine can be obtained.
When the holding plate 10 of the membrane 5 comes into contact with the upper cover 4, the sliding throttle valve 26 fully opens the intake passage 33.

Conversely, when the throttle valve operating lever 56 of the rotating shaft 7 is turned counterclockwise during the deceleration operation of the engine, the driven lever 8 is pushed down by the arm 56a of the throttle valve operating lever 56, and the sliding throttle Valve 26 is depressed. The on-off valve 1 is actuated by the negative pressure of the negative pressure chamber 14 acting on the valve body 15a of the on-off valve 15.
5 is opened, and the negative pressure in the negative pressure chamber 14 decreases. Therefore, when the sliding throttle valve 26 descends, the drag of the negative pressure in the negative pressure chamber 14 to suck up the sliding throttle valve 26 becomes small as shown by the line B in FIG. The valve 26 descends smoothly.

The spring 3 which pushes down the sliding throttle valve 26 against the negative pressure of the negative pressure chamber 14 is long and the spring constant of the spring 3 is small, so that the posture and operation of the spring 3 are stable, and the engine can be operated at high speed. In this range, the load of the spring is not so large, and the driver's operation burden on the acceleration lever 91 is reduced.

[0039]

According to the present invention, an on-off valve is used instead of the pressure switching valve, and the on-off operation of the on-off valve is performed only at the atmospheric pressure and the sliding throttle valve is operated without difficulty. During the acceleration operation, the negative pressure of the intake passage is introduced into the negative pressure chamber through the negative pressure passage. At this time, since the atmosphere passage is closed, the air enters the negative pressure chamber and the negative pressure in the negative pressure chamber is reduced. It will not be done.

At the time of deceleration operation of the sliding throttle valve, the driven lever is pushed in the closing direction by the throttle valve operating lever, and even if the on-off valve is pushed down, the air hole is opened by the negative pressure of the negative pressure chamber,
Since the atmosphere in the atmospheric chamber enters the negative pressure chamber and the negative pressure chamber instantaneously becomes atmospheric pressure, no force acts to prevent the sliding throttle valve from returning due to the deceleration operation.

A hole for inserting and supporting the fuel metering needle valve of the sliding throttle valve is formed as a negative pressure passage for guiding the intake negative pressure of the intake passage to the negative pressure chamber, and the intake negative pressure of the intake passage is provided on the upstream side of the valve plate. Therefore, even if the open / close valve is open, the amount of air taken into the engine does not increase, and the idle speed of the engine does not change.

Since the operation of the sliding throttle valve can be achieved only by opening and closing the atmosphere passage, the air passage can be designed to be optimal, and the malfunction of the sliding throttle valve due to air leakage from the air passage can be prevented. .

The valve plate and the reinforcing plate of the sliding throttle valve are formed integrally or separately, and a holding plate sandwiching the membrane and an upper flange are fastened to the reinforcing plate with bolts, and the wall plate is attached to the reinforcing plate. With the arrangement, the configuration of the sliding throttle valve is not complicated, and the operation of the sliding throttle valve is light.

The proximal flange is pressed against the inclined surface formed at the bottom of the cylindrical portion provided inside the sliding throttle valve by the force of a spring interposed between the upper cover and the proximal flange of the fuel metering needle valve. Since the tip of the fuel metering needle valve is inclined to the downstream side of the intake passage and inserted into the high-speed fuel supply nozzle and abuts against the inner peripheral surface of the high-speed fuel supply nozzle, the area of the negative pressure passage can be made sufficiently large. The posture of the fuel metering needle valve is stable with respect to the fluctuation of the intake negative pressure in the intake passage, and a stable fuel amount can be obtained.

Both the vertical extension and the axial extension of the retaining piece at the end of the remote control cable can be easily locked to the acceleration lever at the outer end of the rotating shaft.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a constant-vacuum sliding throttle valve type vaporizer according to the present invention.

FIG. 2 is a plan sectional view of an identified vacuum sliding throttle valve type vaporizer.

FIG. 3 is an enlarged side sectional view showing a main part of the identified vacuum sliding throttle valve type vaporizer.

FIG. 4 is a perspective view showing a configuration of a valve plate and a wall plate of the identified vacuum sliding throttle valve type vaporizer.

FIG. 5 is a perspective view showing another configuration of a valve plate and a wall plate of the identified vacuum sliding throttle valve type vaporizer.

FIG. 6 is a side sectional view of an on-off valve in the identified vacuum sliding throttle valve type carburetor.

FIG. 7 is a plan sectional view of the on-off valve.

FIG. 8 is a side view showing a state of a forcible operation range of a throttle valve operating lever of the identified vacuum sliding throttle valve type carburetor.

FIG. 9 is a side view showing a state in which the throttle valve operating lever of the identified vacuum sliding throttle valve type carburetor is out of a forced operation range.

FIG. 10 is a side view of an acceleration lever of the identified vacuum sliding throttle valve type carburetor.

FIG. 11 is a front sectional view taken along line 11A-11A in FIG. 10;

FIG. 12 is a front sectional view taken along line 12A-12A of FIG. 10;

FIG. 13 is a front sectional view taken along line 13A-13A of FIG. 10;

FIG. 14 is a diagram illustrating a forced operation region and a constant vacuum operation region of the identified vacuum sliding throttle valve.

FIG. 15 is a diagram illustrating a forced operation region and a constant vacuum operation region of the identified vacuum sliding throttle valve.

[Explanation of symbols]

3: Spring 4: Upper cover 5: Membrane 6: Vaporizer body
7: Rotating shaft 7a: Notched cam 8: Follower lever 8a:
Projection 8b: Notch 9: Cylindrical part 10: Holding plate 13: Atmospheric chamber 14: Negative pressure chamber 15: On-off valve 16: Atmospheric hole 1
7: Opening 19: Spring 20: Guide groove 22: Valve plate 2
3: Bolt 24: Cylindrical part 24a: Slope 25: Pin 26: Sliding throttle valve 26a: Upper flange 26b:
Through hole 26c: groove 27: spring seat 29: fuel metering needle valve 30: high speed fuel supply nozzle 33: intake path 34: acceleration fuel path 37: annular groove 38: low speed fuel path 4
1: bolt 43: second insertion groove 44: bistarter 45: second insertion body 47: groove 48: rivet 4
9: groove 50: reinforcing plate 50a: wall plate 50b: protruding edge 5
0c: inclined surface 56: throttle valve operating lever 56a, 56
b: Arm 58: Forced operation lever 58a, 58b: Arm
61: Release pin 63: First insertion groove 64: Cylinder 65: First insertion body 66: Plunger 68: Start fuel passage 70: Start button 73: Acceleration pump 7
4: Cylinder 75: Piston 78: Forced operation lever 78a, 78b: Arm 80: Return spring 90: Step
91: acceleration lever 92: auxiliary plate 94: retaining piece 9
5: slit 96: retaining piece 97: remote control cable 98: groove 99: hole

Claims (6)

[Claims] 1. A negative pressure chamber is defined above a membrane sandwiched between an upper end wall of a vaporizer main body and an upper cover, and an atmosphere chamber is defined below a membrane, and is orthogonal to an intake passage of the vaporizer main body. A sliding throttle valve coupled to the membrane is supported in the guide opening so as to be able to move up and down, and a rotary shaft for connecting a throttle valve operating lever for controlling the opening of the sliding throttle valve is arranged in the atmosphere chamber, A forced operating lever for engaging and disengaging a driven lever rotatably supported on a shaft with the throttle valve operating lever in accordance with the opening of the sliding throttle valve;
In a constant-vacuum sliding throttle valve type carburetor which is axially supported by the throttle valve operating lever, a notch provided at the tip of the driven lever is connected to a pin of a wall plate disposed parallel to a side wall surface of the sliding throttle valve. Combined, the film and the holding plate on the upper surface of the upper flange,
A constant vacuum slide wherein a reinforcing plate is overlapped on the lower surface, a bolt penetrating the holding plate and the upper end flange is screwed to the reinforcing plate, and the wall plate is formed integrally with the reinforcing plate. Throttle valve carburetor. 2. A constant-vacuum sliding throttle valve type vaporizer according to claim 1, wherein the reinforcing plate having the wall plate and a valve plate of the sliding throttle valve are integrally formed. 3. The reinforcing plate and a valve plate of a sliding throttle valve are formed separately, and a holding plate sandwiching the membrane and the upper end flange are fastened to the reinforcing plate by bolts, and the protrusion of the reinforcing plate is formed. The constant-vacuum sliding throttle valve type carburetor according to claim 1, wherein a slit of the valve plate is engaged with an edge. 4. The constant vacuum according to claim 1, wherein the hole for supporting the fuel metering needle valve of the sliding throttle valve is configured as a negative pressure passage for guiding an intake negative pressure of an intake passage to the negative pressure chamber. Sliding throttle valve type carburetor. 5. The base of a sliding throttle valve is provided with a spring interposed between the upper cover and a base flange of a fuel metering needle valve on an inclined surface formed at the bottom of a cylindrical portion provided inside the sliding throttle valve. 2. The high-speed fuel supply nozzle according to claim 1, wherein the end flange is pressed, the tip of the fuel metering needle valve is inclined toward the downstream side of the intake passage, inserted into the high-speed fuel supply nozzle, and abuts on the inner peripheral surface of the high-speed fuel supply nozzle. Constant vacuum sliding throttle valve carburetor. 6. A remote control cable, which is provided at an end of a remote control cable connecting an acceleration lever and an operation member connected to an outer end of the rotating shaft and extends in a direction perpendicular to the remote control cable. 2. The constant-vacuum sliding throttle valve type vaporizer according to claim 1, wherein a hole for selectively engaging one of the retaining pieces extending in the same direction is provided in the acceleration lever.