JPH10141139A - Choke valve operating device of rotary throttle valve type carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact engine capable of improving the start operability, while effecting sure start by enabling the shift to load running after start with a simple operation without needing operations of both a choke lever and throttle level in the start of the engine. SOLUTION: In a choke valve operating device of a rotary type throttle valvecarburetor 100 provided with a choke valve, a choke valve 17 can be operated manually in the start of an engine, while a start operating mechanism interlocked with the rotation of the throttle valve of the carburetor 100 to open automatically the choke valve 17 is disposed side by side with the carburetor 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a choke valve operating device for an engine provided with a choke valve and a rotary throttle valve (throttle valve) in a carburetor.

[0002]

2. Description of the Related Art In general-purpose small general-purpose engines,
The carburetor is equipped with a choke valve, and the choke lever for operating the choke valve and the throttle lever are individually operated.When the engine is started, the choke valve is closed, the pressure around the fuel nozzle is reduced, and the fuel supply is increased. By doing so, the starting is facilitated, and after the engine is started, the choke valve is opened, and at a predetermined air-fuel ratio, the throttle valve, that is, the throttle valve is opened and closed by the throttle lever, thereby adjusting the engine output.

[0003] As one of the carburetors with a rotary throttle valve for such a small engine, a device disclosed in Japanese Utility Model Laid-Open Publication No. 6-83943 has been conventionally provided. FIG. 4 to FIG.
FIG. 4 shows an outline of a choke valve operating device in No. 83943, FIG. 4 is a longitudinal sectional view of a carburetor, FIG.
FIG. 5 is a sectional view taken along the line AA in FIG. 4.

In FIGS. 4 to 6, reference numeral 100 denotes a vaporizer,
5 is a rotary throttle valve, that is, a throttle valve, 021 is a throttle valve lever, A is an upper fuel increasing mechanism,
B is a constant pressure fuel supply mechanism, and C is a primer pump. In this small engine, the operation lever is manually turned at the time of starting to increase the degree of opening of the fuel nozzle of the carburetor, thereby increasing the supply fuel. The first operation lever is automatically returned to control the opening degree of the fuel nozzle by rotation of the throttle valve lever, and the choke valve is omitted.

In such a conventional small engine, during engine operation, the amount of fuel is controlled by rotation of the throttle valve 05 and axial movement. As shown in FIG. 6, the cylindrical cam member 045 provided with the manual operation lever 045a is provided with a plurality of cam surfaces 060a and 060b having different heights from the axis. When the engine is cold started, when the cylindrical cam member 045 is rotated by the operation lever 045a against the force of the spring 049, the flat cam surface 060b contacts the lower surface of the throttle valve lever 021. As a result, the throttle valve lever 021 is pushed upward, the fuel amount is increased, and the cold start of the engine is facilitated.

After the engine starts, the throttle valve lever 02
When 1 is rotated in the full opening direction, the cam surface 060b of the cylindrical cam member 045 is disengaged from the side edge 021a of the throttle valve lever 211, whereby the cylindrical cam member 045 is pushed back to the original position by the spring 049. Such an engine is easy to start, and the starting position of the throttle valve is stably maintained without being affected by vibration and the like, and a rich air-fuel mixture can be stably supplied at the time of starting.

[0007] Japanese Patent Application Laid-Open No. 4-30241 discloses a technique in which a choke valve and a throttle valve (throttle valve) are operated in association with each other to facilitate starting.

In this invention, a cam arm fixed to the rotating shaft of the choke valve is provided, and an outer periphery of the cam arm is provided at a swing position corresponding to the opening degree of the choke valve during warm-up operation and cold operation of the engine. A choke valve provided with a locking portion for locking the arm and a lock arm at a swinging position corresponding to the opening degree of the throttle valve at the time of each operation against each elastic machine (spring); By pulling the operating device, the choke valve and the throttle valve are fixed at the starting position, and after starting the engine, the operating device of the choke valve is pushed in to switch to the warm-up operation position,
Then, the operation device of the throttle valve is operated by a small amount in the opening direction to return to the original position.

[0009]

In a conventional general small engine, a choke lever and a throttle lever (throttle valve operating lever) are individually operated, the choke valve is closed when the engine is started, and after the engine is started. The choke valve is opened, and the engine output is adjusted by a throttle lever. Each lever is operated individually. Therefore, it takes time and effort to drive the engine, and there is a problem in driving operability.

Further, the prior art shown in Japanese Utility Model Laid-Open No. 6-83943 has a system in which the choke valve is omitted and the fuel nozzle of the carburetor is opened at startup to increase the amount of fuel. Is simple, but the mechanism for operating the opening of the fuel nozzle is complicated, and a low pressure is not applied around the fuel nozzle, so that a reliable start may not be obtained.

Further, in the prior art provided in Japanese Utility Model Laid-Open No. 4-30241, when the choke valve is opened after the engine has been started, the choke operating device is operated to open the choke valve and open the throttle valve. It is necessary to operate in the direction, and the complexity of the operation at the time of starting is the same as that of the conventional general small engine.

In view of the above-mentioned problems in the prior art, the present invention improves the start operability by enabling the operation to be switched to the load operation after the start by a simple operation without having to operate both the choke lever and the throttle lever at the start of the engine. It is another object of the present invention to provide a small engine capable of reliably starting.

[0013]

According to the present invention, there is provided a choke valve operating device for a rotary throttle valve carburetor having a choke valve at an inlet of a carburetor, wherein the choke valve is an engine. A start operation mechanism that can be manually operated at the time of starting and that automatically opens the choke valve in conjunction with the rotation of the throttle valve of the carburetor after the engine is started is provided in the carburetor. A choke valve operating device for a rotary throttle valve type carburetor is proposed.

Further, a second invention embodies the first invention, and in the choke valve operating device,
A choke lever provided rotatably at the air inlet to open and close the air inlet, a choke lever provided on a rotation shaft of the choke valve and having an engagement arm portion, A throttle valve operating lever having an end engaged with the engaging arm of the choke lever when the throttle valve is closed, and the throttle valve closing lever when the engine is started when the throttle valve is closed. An end of the throttle valve operating lever is engaged with the engagement arm of the choke lever to hold the choke valve in the closed position, and at a predetermined rotation angle of the throttle valve, the engagement arm and the end portion The engagement is released, the choke valve is opened, and after the engine is started, the output can be adjusted only by the throttle valve operating lever.

According to this invention, when the engine is started, the choke lever urged in the opening direction of the choke valve by the spring is operated in the closing direction against the elasticity of the spring, and the engagement of the choke lever is performed. Lock the arm to the end of the throttle valve operating lever (throttle lever).

When the engine is started in this state (the choke valve is closed), the pressure in the carburetor throttle drops because the choke valve is closed as described above,
Fuel is increased and a rich mixture is delivered into the cylinder to ensure a reliable start.

After the engine is started, after the idling operation (warm-up operation), when the throttle valve operating lever is pulled in the direction of increasing the fuel, the end of the throttle valve operating lever is disengaged from the engagement arm of the choke lever. However, since the choke lever is biased by a spring so that the choke valve is opened, when the engagement arm is disengaged from the end, the choke valve is actuated by the spring via the choke lever. It is automatically moved in the opening direction by the elastic force, and shifts to the state of normal load operation with the choke valve open.

As described above, in the present invention, after starting,
When starting the load operation, the operation can be shifted simply by operating the throttle valve operating lever without requiring the operation of the choke lever, and the starting operation becomes extremely easy. It becomes possible. In addition, at the time of starting, the choke valve maintains the closed state of the choke valve by the engagement between the engagement arm of the choke lever and the end of the throttle operation lever, so that the start is reliably performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 is a plan view of a choke valve operating device of a rotary throttle valve type carburetor for a small engine according to an embodiment of the present invention, FIG. 2 is a view taken in the direction of the arrow Z in FIG. 1, and FIG. It is an arrow view.

1 to 3, reference numeral 1 denotes an air cleaner cover, 2 denotes an air cleaner case, and 100 denotes a carburetor provided between the air cleaner case and an engine body (not shown). Is a rotary throttle valve type carburetor provided with a throttle valve (throttle valve). A furnace member (not shown) is housed in an air cleaner chamber formed inside the air cleaner case 2 and the air cleaner cover 1 to purify intake air.

3 is a vaporizer body of the vaporizer 100, 3a
Is an intake passage provided in the carburetor body 3, and 4 is a heat insulating joint pipe for connecting the carburetor body 3 to the engine body. Reference numeral 5 denotes a cylindrical rotary throttle valve type throttle valve, and reference numeral 5a denotes a throttle shaft to which the throttle valve 5 is fixed and which serves as a rotation shaft. Reference numeral 6 denotes a throttle lever which is fixed to the throttle shaft 5a. The throttle valve 5, the throttle shaft 5a, and the throttle lever 6 are integrally movable up and down.
It is urged downward by a compression spring (not shown).

Reference numeral 6a denotes a cam plate provided integrally with the throttle lever 6. The cam plate 6a has an inclined cam whose thickness increases counterclockwise in FIG.
Reference numeral 7 denotes a main body cover of the vaporizer 100, and reference numeral 7a denotes a cam pressing piece provided on the main body cover 7. When the inclined cam of the cam plate 6a is engaged with the cam pressing piece 7a and the throttle lever 6 rotates clockwise, that is, as the throttle valve 5 is opened, the throttle lever 6 is pushed upward, and the fuel nozzle ( (Not shown). Reference numeral 8 denotes a swivel for stopping an end of an operation wire 11 rotatably attached to the throttle lever 6. Reference numeral 9 denotes a support plate, which is attached to the main body cover 7 and supports a protection tube for the operation wire 11 of the throttle lever 6.

Reference numeral 15 denotes a choke lever, 16 denotes a choke lever shaft to which the choke lever 15 is fitted, 17 denotes a choke valve, and 18 denotes a return spring. The choke lever 15, the choke lever shaft 16, and the choke valve 17 are integrally combined and can rotate around the choke lever shaft 16. Reference numeral 15a denotes an engagement arm provided on the choke lever 15, and a step portion 15b capable of engaging with an end portion 6b of the throttle lever 6, which will be described later, is formed at the tip of the arm 15a. 18 is a torsion spring type return spring attached to the choke lever 15,
It is urged in a direction to open the choke valve 17, that is, in a counterclockwise direction in FIG.

In FIG. 2, the position of the choke lever 15 indicated by a solid line and the position of the choke valve 17 indicated by a broken line indicate a state in which the choke valve 17 blocks the inlet of the air supply passage 3a when the engine is started. At the position of the choke lever 15, as shown in FIG. 3, the step 15b of the engagement arm 15a of the choke lever 15 is engaged with the end 6b of the throttle lever 6, and
Are locked when the choke valve 17 is closed. In FIG. 2, the positions of the choke lever 15 ′ and the choke valve 17 indicated by a two-dot chain line indicate a state where the choke valve 17 ′ is open, that is, a position in a load operation state of the engine.

The return spring 18 may be a tension spring that pulls the choke lever 15 in the choke valve opening direction. Further, the throttle portion of the carburetor 100 according to this embodiment, and the constant pressure fuel supply mechanism and the primer pump connected thereto may have the same structure as the conventional one shown in FIG.

Next, the operation of the choke valve operating device configured as described above will be described. When the engine is started, first, the tip of the choke lever 15 is manually pushed, and the choke lever 15 is rotated against the return spring 18 to change the choke valve 17 from "open" to "closed". As a result, the step 15b of the choke lever 15a is locked by the end 6b of the throttle lever 6, and the choke valve 17 maintains the "closed" state.

Next, the engine is started by operating a starter (not shown). At this time, since the choke valve 17 holds the "closed" state as described above,
The air pressure in the throttle of the carburetor 100 is reduced, the fuel is increased and sucked in, and the rich mixture is sent to the combustion chamber of the engine, so that the engine can be started easily. After the engine is started, a warm-up operation is performed, then the operation wire 11 is pulled, and the throttle lever 6 is rotated clockwise in FIG. 1 to increase the fuel flow rate and increase the engine output.

With this operation, when the rotation angle of the throttle lever 6 becomes a in FIG. 1A, the step 15b of the engagement arm 15a of the choke lever hooked on the end 6b is disengaged from the end 6b. As a result, the choke valve 17 is rotated by the return spring 18 and automatically opened.
And normal operation becomes possible. At this time, the throttle lever is at the position 6 'in FIG. The choke lever 15 is maintained in a state of being separated from the end 6b of the throttle lever 6 by a return spring 18, and the choke valve 1
7 remains open as described above, and the load operation continues smoothly.

[0030]

As described above, according to the present invention, the choke valve is closed, the engagement arm thereof is engaged with the end of the throttle lever, and after the engine is started, the engine is warmed up and the load operation is started. When entering, if the throttle lever, that is, the throttle valve operating lever is rotated, the engagement arm and the end of the throttle valve operating lever are disengaged, and the choke lever is resiliently moved by the spring force of the choke valve spring. Thereby, the choke lever is automatically returned to the position where the choke valve is opened. Therefore, the choke valve can be opened only by moving the throttle valve operating lever to the high-speed side after starting,
The starting operation becomes extremely easy.

At the time of starting, the choke valve is kept closed by the engagement between the engagement arm of the choke lever and the end of the throttle valve operating lever, so that the start can be reliably performed. Further, since the mechanical engagement structure is formed by the engagement arm, the end portion, and the spring, the structure is simple and a low-cost device can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a choke valve operating device of a rotary throttle valve carburetor for a small engine according to an embodiment of the present invention.

FIG. 2 is a view taken in the direction of the arrow Z in FIG. 1;

FIG. 3 is a view as viewed in the direction of the arrow Y in FIG. 1;

FIG. 4 is a longitudinal sectional view of a conventional small engine carburetor.

FIG. 5 is a plan view of the conventional vaporizer.

FIG. 6 is a sectional view taken along line AA of FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 carburetor 2 air cleaner case 3 carburetor body 3a air supply passage 5 throttle valve 5a throttle shaft 6 throttle lever 6a cam plate 6b end 7a cam pressing piece 15 choke lever 15a engagement arm 15b step 17 choke valve 18 return spring

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[Procedure amendment]

[Submission date] March 28, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

With this operation, when the rotation angle of the throttle lever 6 becomes a in FIG. 1A, the step 15b of the engagement arm 15a of the choke lever hooked on the end 6b is disengaged from the end 6b. As a result, the choke valve 17 is rotated by the return spring 18 and automatically opened.
And normal operation becomes possible. At this time, the throttle lever is at the position 6 'in FIG. The choke lever 15 is maintained in a state of being separated from the end 6b of the throttle lever 6 by a return spring 18, and the choke valve 1
7, as described above, while the result open load operation is continued smoothly.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (2)

[Claims] 1. A choke valve operating device for a rotary throttle valve type carburetor having a choke valve at an air inlet of a carburetor, wherein the choke valve is manually operable when the engine is started, and the engine is started. A choke valve operation of the rotary throttle valve type carburetor, wherein a start operation mechanism for automatically opening the choke valve in conjunction with rotation of the throttle valve of the carburetor is provided in the carburetor. apparatus. 2. A choke valve operating device for a rotary throttle valve type carburetor having a choke valve at an air inlet of a carburetor, wherein the choke valve is rotatably provided at the air inlet so that the air inlet is connected to the choke valve. A choke lever configured to open and close and having an engagement arm provided on a rotation shaft of the choke valve; a spring for urging the choke valve in an opening direction; and the choke lever when the throttle valve is closed. A throttle valve operating lever having an end engaged with the engaging arm of the throttle valve, wherein the end of the throttle valve operating lever engages with the engaging arm of the choke lever when the throttle valve is closed when the engine is started. Then, the choke valve is held at the closed position, the engagement between the engagement arm and the end is released at a predetermined rotation angle of the throttle valve, and the choke valve is opened, After Jin started, the rotary throttle valve type carburetor choke valve device being characterized in that a possible output adjustment only by the throttle valve lever.