JP2002221097A - Rotary throttle valve type caburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel rotary throttle valve type caburetor excellent in the durability without changing the fuel restriction value during the long-time operation, preventing the value from exceeding an exhaust gas restriction value. SOLUTION: In the rotary throttle valve type caburetor, the opening of a restriction hole 20 of the throttle valve 12 is increased/reduced by the rotation of the throttle valve 12, and the opening of a fuel injection hole 19 of a fuel feed pipe 18 projecting toward the restriction hole 20 is increased/reduced by the axial movement of the throttle valve 12 and a fuel adjusting needle 15. A housing 32 with a bottom wall 45 for closing a valve chamber 17 is connected to the upper wall of a caburetor body 33 and a valve shaft 43 for connecting a throttle lever 2 to a boss part 41 on the upper surface of the bottom wall 45 is supported in the housing. A cam mechanism consists of a cam disk 10 abutting to the lower surface of the bottom wall 45 and a pin 46 with a follower 29 supported at the upper end of the throttle valve 12. A return spring 6 is engaged between a projecting piece 9 projecting from the cam disk 10 toward the inside of the housing 32 via an opening 28 of the bottom wall 45 and the throttle lever 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel rotary throttle valve carburetor having excellent durability that does not exceed a fuel regulation value during operation.

[0002]

2. Description of the Related Art In a conventional rotary throttle valve carburetor, a fuel adjusting needle is provided on a valve shaft of a rotary throttle valve (hereinafter, simply referred to as a throttle valve). After several turns, the set value of the fuel amount may fluctuate, though very slightly. Further, in the conventional rotary throttle valve type carburetor, since the throttle valve and the valve shaft are integrated, when the valve shaft becomes long, precise processing is required to obtain concentricity between the throttle valve and the valve shaft. When the valve shaft of the throttle valve becomes longer, when the inner wire locked to the throttle valve lever is pulled strongly, a bending moment acts on the valve shaft and the throttle valve to tilt them, and the bearing portion of the valve shaft and the throttle valve Wear is promoted on the fitting portion of the valve chamber. Further, since the outer end of the valve shaft and the throttle valve lever are open to the outside, there is a possibility that dust or moisture in the atmosphere may enter the inside of the throttle valve.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a novel rotary throttle valve having excellent durability, in which the amount of fuel changes during long-term operation and does not exceed an exhaust gas regulation value. It is to provide a type vaporizer.

Another object of the present invention is to provide a rotary throttle valve type carburetor which is suitable for a relatively large internal combustion engine, particularly for a two-wheeled vehicle, a four-wheeled buggy vehicle and the like.

Another object of the present invention is to provide a rotary throttle valve type carburetor which does not require a high degree of machining precision in concentricity between the throttle valve and the valve shaft.

[0006]

According to the present invention, a throttle valve having a throttle hole is rotatably and axially moved in a valve chamber orthogonal to an intake passage passing through a carburetor body. A fuel adjustment needle supported by a throttle valve is fitted into a fuel supply pipe which is fitted as possible and protrudes from the fuel chamber to the throttle hole, and the degree of opening of the throttle hole is adjusted by turning the throttle valve. In the rotary throttle valve type carburetor, which adjusts the opening of the fuel injection hole of the fuel supply pipe by axial movement of the fuel supply pipe, a housing having a bottom wall for closing a valve chamber is connected to an upper wall of the carburetor body, and A cam mechanism is formed from a cam disc that contacts a lower surface of the bottom wall and a pin that has a follower supported on the upper end surface of the throttle valve, supporting a valve shaft that couples a throttle valve lever to a boss portion on the upper surface, The interior of the housing from the cam disk through the opening in the bottom wall Characterized in that lock the spring back between the projecting pieces projecting and the throttle valve lever.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention does not require any troublesome equipment such as a limiter cap and the like. Even if the driver adjusts the fuel amount on his own, the simple structure can reduce the low-speed fuel amount within a range not exceeding the exhaust gas regulation value. Be able to adjust. Since the movable part around the valve shaft is completely sealed by the housing, dust and moisture do not enter the inside of the vaporizer.

The low-speed fuel adjusting mechanism is a low-speed fuel adjusting bolt screwed to the outer wall of the housing, and is adjusted by rotating the cam disk about the valve shaft of the throttle valve.

When the throttle valve is rotated in a direction to increase the amount of intake air, the cam surface of the cam disk is set so that the opening of the fuel injection hole of the fuel supply pipe increases.

When the cam disk is rotated in a state where the throttle valve does not move, the throttle valve and the fuel adjustment needle fixed to the valve shaft move in the axial direction in accordance with the inclination of the cam disk. The opening of the fuel injection hole will increase or decrease.

Since the low-speed fuel adjustment bolt is screwed to the outer wall of the housing, adjustment is easy, and the fuel set value does not change even if the throttle valve is turned.

Since the atomization characteristics of fuel during high-speed operation of the internal combustion engine can be improved and the amount of fuel in the low-speed fuel passage can be freely changed in accordance with the characteristics of the internal combustion engine, the minimum amount of fuel optimal for the internal combustion engine can be used. This makes it possible to obtain a rotary throttle valve type carburetor having excellent fuel efficiency and excellent exhaust gas characteristics.

[0013]

1 is a front sectional view of a rotary throttle valve carburetor according to the present invention, and FIG. 2 is a plan sectional view of the rotary throttle valve carburetor. In the carburetor body 33 through which the intake passage 34 passes, a cylindrical valve chamber 17 orthogonal to the intake passage 34 is provided, and the throttle valve 12 having the throttle hole 20 in the valve chamber 17 is rotatably and vertically movable. Be mounted. A not-shown, preferably film-type constant-pressure fuel chamber (not shown) is connected to the bottom wall of the vaporizer main body 33. The fuel supply pipe 18 is provided on the projected wall 22 of the bottom wall of the vaporizer main body 33.
Are fitted and supported, and a cylindrical portion 21 is formed on the throttle valve 12 so as to externally fit the protruding wall 22 and communicate with the throttle hole 20. The constant pressure fuel chamber communicates with the fuel supply pipe 18 via the fuel passage 23. A fuel injection hole 19 is formed at the upper end of the fuel supply pipe 18, and a fuel adjustment needle 15 projecting downward from the valve shaft 43 of the throttle valve 12 is fitted. At the inlet of the intake passage 34, a high-speed fuel injection hole 35 for supplying fuel from the constant pressure fuel chamber to the intake passage 34 via the fuel passage 36 is provided.

A cylindrical housing 32 is fitted on the upper wall of the vaporizer main body 33 and is fixed by bolts 37. A boss 4 integral with the bottom wall 45 is provided at the axis of the housing 32.
The valve shaft 43 is rotatably fitted to the boss portion 41. The throttle valve lever 2 is connected to the upper end of the valve shaft 43, and a remote control cable 50 is connected to one end of the throttle valve lever 2.
The locking hole 4 for locking the end retaining piece of the inner wire 56 of FIG. 2 is formed. The inner wire 56 is wound around an annular groove 7 formed on the peripheral wall of the fan-shaped throttle valve lever 2 and protrudes outside the housing 32. The upper end of the housing 32 is closed by a lid 31 made of a transparent material.

One end of the return spring 6 lightly wound around the boss portion 41 is connected to the throttle valve lever 2, and the other end is connected to the projection 9 projecting from the cam disk 10 through the opening 28 of the bottom wall 45 into the housing 32. Locked. The throttle valve lever 2, the valve shaft 43 and the throttle valve 12 are urged to rotate to the idle position by the force of the return spring 6, and the cam disk 10 and the follower 2 are rotated.
9 is pushed down by the cam mechanism. The base end 42 of the fuel adjusting needle 15 is screwed into the inner space of the valve shaft 43 and closed by the stopper 3. A coil spring interposed between the base end portion 42 of the fuel adjustment needle 15 and the inner space of the valve shaft 43 prevents the threaded portion of the base end portion 42 of the fuel adjustment needle 15 from being loosened. I have. Notches 13 are provided at both ends of the plate-like lever 16 connected to the lower end of the valve shaft 43. A circular recess 14 provided in the upper end wall of the throttle valve 12
The notch 13 is engaged with a pair of pins 46 having a follower 29 supported on the upper end of the throttle valve 12.

As shown in FIG. 2, the throttle valve lever 2 has a fan shape, and an end of the throttle valve lever 2 is returned to an idle position adjusting bolt 5 screwed to a wall 32a of a housing 32 by a return spring 6. And the housing 3
The low-speed fuel adjusting bolt 8 screwed to the second wall portion 32b has a protruding piece 9 projecting from the cam disk 10 through the opening 28 of the bottom wall 45 adjacent to the other end of the throttle valve lever 2 into the housing 32. Are brought into contact by the force of the return spring 6. A coil spring 5b for preventing the idle position adjusting bolt 5 from loosening is interposed between the head 5a of the idle position adjusting bolt 5 and the side wall of the carburetor body 33. Similarly, a coil spring 8b for preventing the low-speed fuel adjustment bolt 8 from loosening is interposed between the head 8a of the low-speed fuel adjustment bolt 8 and the side wall of the carburetor body 33. The head 8a is formed in a cup shape.
When the low-speed fuel adjusting bolt 8 is screwed until the abutment with the side wall of the carburetor body 33, the low-speed fuel amount becomes maximum. The remote control cable 50 is configured by inserting the inner wire 56 into the outer tube 53. The outer tube 53 is fitted and supported via a soft tube 51 on a metal support tube 52 connected to the projecting wall of the housing 32. Inner wire 56
The part projecting from the opening of the housing 32 is the bellows 5.
4 is covered.

When the throttle valve lever 2 is rotated in the direction of arrow x in FIG. 2 from the idle position shown in FIG. 1, the throttle valve 12 is also rotated in the same direction via the lever 16 at the lower end of the valve shaft 43, and the throttle hole is rotated. The opening degree of the intake passage 20 with respect to the intake path 34 increases. At the same time, the throttle valve 12 is pushed up by the cam mechanism including the cam disk 10 and the follower 29, and the fuel adjustment needle 1
5, the opening degree of the fuel injection hole 19 increases. The fuel in the constant pressure fuel chamber is supplied to the intake passage 34 via the fuel passage 23, the fuel injection hole 19 of the fuel supply pipe 18, and the throttle hole 20. The fuel in the constant-pressure fuel chamber is supplied to the fuel passage 36 and the high-speed fuel injection hole 3.
5 and is supplied to the intake path 34.

In the present invention, the valve shaft 43 and the throttle valve 12 are formed separately, and the lever 16 at the lower end of the valve shaft 43 is
Is engaged with the pair of pins 46 supported on the valve shaft 43.
When the throttle valve 12 is rotated by the throttle valve lever 2, even if a force that tilts the valve shaft 43 is applied, the tilt of the valve shaft 43 is reduced.
The throttle valve 12 smoothly rotates inside the valve chamber 17 while always maintaining concentricity with the valve chamber 17. Even if the valve shaft 43 is lengthened in order to mount the return spring 6, the throttle valve 12 is not adversely affected by the movement of the valve shaft 43 falling down by the throttle valve lever 2. Even if the valve shaft 43 is formed of a synthetic resin, the throttle valve 12 is not affected by the shape change due to the temperature of the valve shaft 43. Further, only the valve shaft 43 can be detached from the carburetor main body 33, so that the fuel and air adjusting portions of the carburetor can be easily disassembled and cleaned.

As shown in FIG. 3, the cam disk 10 is brought into contact with the lower surface of the bottom wall 45 of the housing 32, and a pair of followers 29 projecting from the upper end of the throttle valve 12 are arranged on the cam disk 10 with respect to the center. Since the cam mechanism 10 is engaged with the pair of cam surfaces 10a formed in a point symmetry, the operation of the cam mechanism is controlled by the valve shaft 4.
A smooth cam operation can always be obtained without being affected by the inclination or inclination of the cam 3.

[0020]

According to the present invention, as described above, a throttle valve having a throttle hole is rotatably and axially fitted in a valve chamber orthogonal to an intake passage passing through the carburetor body, and is inserted from the fuel chamber. A fuel adjustment needle supported by a throttle valve is fitted into a fuel supply pipe protruding into the throttle hole, the opening of the throttle hole is adjusted by turning the throttle valve, and the fuel in the fuel supply pipe is adjusted by axial movement of the throttle valve. In a rotary throttle valve type carburetor for adjusting the degree of opening of an injection hole, a housing having a bottom wall for closing a valve chamber is connected to an upper wall of the carburetor body, and a throttle valve lever is provided on a boss on an upper surface of the bottom wall. A cam mechanism is formed from a cam disk that supports the valve shaft to be coupled and abuts on the lower surface of the bottom wall and a pin having a follower that is supported on the upper end surface of the throttle valve. A projecting piece projecting into the housing through an opening and the throttle valve lever And which was sealed return lock the spring between the can driver without exceeding the emission control value to adjust the low-speed fuel quantity by low speed fuel adjustment bolt.

A protruding piece projecting from the cam disk through the opening in the bottom wall of the housing to the inside of the housing abuts on the low-speed fuel adjustment bolt, and the cup-shaped head of the low-speed fuel adjustment bolt abuts on the wall of the housing. When the amount of fuel at the idle position becomes maximum and the low-speed fuel adjustment bolt is unscrewed, the opening of the fuel injection hole becomes small, so that the air-fuel ratio does not exceed the regulation value.

Since the opening degree of the throttle hole and the opening degree of the fuel injection hole at the idle position can be separately adjusted, an appropriate air-fuel ratio can be set for the entire operation range.

Since the operation part of the throttle valve is completely sealed by the housing, it is possible to prevent dust and moisture from entering the inside of the vaporizer.

By making the housing lid transparent,
The engagement state of the throttle valve lever and the inner wire can be checked from the outside.

By optimizing the shape of the engagement groove of the throttle valve lever and the shape of the inner wire, the end of the inner wire can be removed by merely inserting the inner wire from the opening of the housing without removing the housing cover. Can be locked.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a rotary throttle valve carburetor according to the present invention.

FIG. 2 is a plan sectional view of the rotary throttle valve type carburetor.

FIG. 3 is a bottom view of a cam disk in the rotary throttle valve carburetor.

[Explanation of symbols]

2: throttle valve lever 4: locking hole 5: idle position adjusting bolt 6: return spring 7: groove 8: low speed fuel adjusting bolt 9: projecting piece 10: cam disk 10a: cam surface 12: throttle valve 13: notch 14 : Hollow 15: fuel adjusting needle 16: lever 17: valve chamber 18: fuel supply pipe 19: fuel injection hole 20: throttle hole 21: cylindrical portion 22: projecting wall 23: fuel passage 28: opening 29: follower 31: lid 32 : Housing 33: Vaporizer main body 34: Intake path 35: High-speed fuel injection hole 36: Fuel passage 37: Bolt 41: Boss 42:
Inside space 43: Valve shaft 45: Bottom wall 46: Pin 50: Remote control cable 5
2: Support tube 53: Outer tube 54: Bellows
56: Inner wire

Claims (8)

[Claims] 1. A throttle valve having a throttle hole is rotatably and axially fitted in a valve chamber orthogonal to an intake passage passing through a carburetor body, and a fuel supply projecting from the fuel chamber to the throttle hole. A fuel adjusting needle supported by a throttle valve is fitted into the pipe, and the opening of the throttle hole is adjusted by rotating the throttle valve, and the opening of the fuel injection hole of the fuel supply pipe is adjusted by moving the throttle valve axially. In a rotary throttle valve type carburetor, a housing having a bottom wall closing a valve chamber is connected to an upper wall of the carburetor body, and a valve shaft connecting a throttle valve lever to a boss on an upper surface of the bottom wall is supported. A cam mechanism is formed from a cam disk abutting on the lower surface of the bottom wall and a pin having a follower supported on the upper end surface of the throttle valve. From the cam disk, the inside of the housing passes through an opening in the bottom wall. A return spring is locked between the protruding piece and the throttle valve lever. Rotary throttle valve type carburetor, characterized in that. 2. The valve shaft and the throttle valve are formed separately, and a plate-like lever having a U-shaped notch at each end engaged with the pin is connected to a lower end of the valve shaft. A rotary throttle valve type carburetor according to the above. 3. A rotary throttle valve carburetor according to claim 2, wherein a cam surface of said cam disk and two pins supported by said throttle valve are provided symmetrically with respect to said valve axis. 4. The low-speed fuel adjusting mechanism according to claim 3, wherein the cam disk is rotatable about the valve shaft.
A rotary throttle valve type carburetor according to the above. 5. A rotary throttle valve carburetor according to claim 4, wherein a cover made of a transparent material is provided on said housing covering said throttle valve lever. 6. The rotary throttle valve carburetor according to claim 4, wherein a bench lily is provided at an inlet of said intake passage, and said bench lily is provided with a high-speed fuel injection hole. 7. After the fuel adjusting needle is screwed into a screw hole in an inner space of the valve shaft to set a predetermined fuel amount, the fuel adjusting needle is screwed into the inner space so that the fuel adjusting needle cannot be adjusted from the outside. The rotary throttle valve type vaporizer according to claim 4, wherein the stopper is press-fitted. 8. The rotary throttle valve type according to claim 4, wherein a groove portion for engaging a remote control cable provided on a peripheral edge of said throttle valve lever is provided axially inward of a tip of said valve shaft. Vaporizer.