JPH0454827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve control device for appropriately controlling the valve opening of a carburetor for an internal combustion engine depending on the warm-up state of the engine. Concerning improvements to the two-stage complete detonation mechanism.

[Prior Art] Generally, in order to increase the opening degree of the choke valve when starting an engine, a bimetal whose resistance increases when the engine temperature is low is coupled to the choke lever, and
This choke lever is connected via a connecting rod and a diaphragm rod to a diaphragm that responds to the negative pressure of the engine.

Furthermore, Utility Model Application Publication No. 15956/1983,
As described in Japanese Patent Application Laid-open No. 177421 and Japanese Patent Application Laid-Open No. 54-60626, a two-stage switching spring is provided between the connecting rod and the diaphragm to control the choke valve in two stages. With this configuration, the opening of the choke valve is controlled in accordance with the difference between the resistance force of the bimetal and the biasing force of the two-stage switching spring.

[Problems to be Solved by the Invention] As described above, the CHYOK valve is controlled in two stages due to the difference between the resistance force of the bimetal and the biasing force of the two-stage switching spring, but there is no external force between them. If this happens, the intake valve may not be closed when the engine is not yet warmed up, resulting in a lean air-fuel ratio, or the intake valve may be closed after the engine has been warmed up, causing the air-fuel ratio to become rich.

However, in the above-mentioned conventional technology, since the two-stage switching spring is a compression spring, the biasing force applied to the shoe yoke lever varies depending on the seat.

The above-mentioned conventional technology has a structure in which the connecting rod slides using the opening of the diaphragm chamber as a guide, and friction occurs when the connecting rod moves.

In addition, in the above-mentioned conventional technology, the connecting rod is made of, for example, a press-formed steel plate or a
Quite heavy materials are used, such as ~4 mm soft iron rods. Also, steel was used for the grommet that connects the connecting rod and the choke lever. In this way, since the materials used for each part were quite heavy, the inertia caused by changes in engine vibration increased.

In this way, in the above-mentioned conventional technology, the load fluctuation due to the seat of the two-stage switching spring, the friction between the diaphragm rod and the diaphragm chamber,
Also, a large inertial force due to vibration changes was applied between the bimetal and the two-stage switching spring, making it impossible to obtain an appropriate opening degree of the yoke valve in accordance with the warm-up of the engine.

An object of the present invention is to provide a two-stage complete explosion mechanism for an automatic choke device that can reduce the external force applied between the bimetal and the two-stage switching spring, and obtain an appropriate choke valve opening depending on the warm-up of the engine. be.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a tension spring between the diaphragm rod and the choke lever for controlling two-stage switching of the choke valve,
The connecting rod that transmits the movement of the diaphragm to the choke lever is made of piano wire, and
Bend both ends of this piano wire into a hook shape, cover that part with a grommet molded with resin, provide a pin that slides on the inner circumference of this grommet, connect the piano wire to the piano wire via this pin, and connect the diaphragm chain. The opening of the bar is sized so as not to come into contact with the diaphragm rod.

[Function] With the above configuration, firstly, the spring that controls the two-stage switching of the choke valve disposed between the diaphragm rod and the choke lever is a tension spring instead of a compression spring. , load fluctuations due to sitting shoes do not occur.

Furthermore, since the connecting rod that transmits the movement of the diaphragm to the choke lever is made of piano wire, and the grommet that links the connecting rod and the choke lever is made of resin, weight can be reduced. Therefore, the inertial force caused by changes in engine vibration can be reduced.

Furthermore, since the opening of the diaphragm chamber and the diaphragm rod do not come into contact with each other, the occurrence of friction can be eliminated.

〔Example〕

Before explaining the present invention, a first example of the prior art will be explained.
This will be explained with reference to FIGS. 2 and 3.

Figure 1 is a partial diagram of the complete explosion mechanism, diaphragm 1
is integrated with guide 2 and diaphragm chamber 3
Built-in spring 4.

The diaphragm rod 5 moves within the case 2 against the two-stage switching spring 6.

The tooth yoke lever 7 is loosely engaged with the yoke shaft 8 as an axis, and is connected to the diaphragm rod 5 via a connecting rod 9.

The yoke valve 10 is fixed to the yoke shaft 8. The conduit 11 transmits the suction negative pressure downstream of the throttle valve to the diaphragm chamber 3.

FIG. 2 is a sectional view showing the connecting portion of the connecting rod 9, which is connected via grommets 13, 13' with pins 12, 12' as axes.

FIG. 3 is an opening characteristic diagram of the check valve 10, which shows the lean limit a, rich limit b, variation ranges c and c' of the check valve opening characteristic of the prior art, and the check valve of the present invention based on the engine's required mixture ratio. The variation ranges d and d' of the opening characteristics are shown.

The conventional structure has the disadvantage that the stroke of the diaphragm 1 is not accurately transmitted as the valve opening α° due to variations in the two-stage switching spring 6, sliding friction between the diaphragm rod 5 and the guide 2, and play in the connecting rod 9. be.

For this reason, there are many variations in the opening characteristics of the choke valve, and those with a large opening will approach the lean limit a, causing operational problems, and conversely, those with a small opening will approach the rich limit b, resulting in fouling of the spark plug, waste of fuel, and harmful Disadvantages such as increased exhaust gas arise.

The present invention eliminates such disadvantages, and a side view of an embodiment is shown in FIG. 4.

The diaphragm rod 14 is integral with the diaphragm 1 and has a hole 16 in which a spring 15 is inserted.

The chain lever 18 is provided with a plurality of holes 19 for hanging the springs 15. Diaphragm rod 1
4 and chain lever 18 are connecting rod 2
It is linked with 0.

FIG. 5 is a plan view of the present invention. The thermostat cover 21 is provided with a heater 22 and a bimetal 23. One end of the bimetal 23 is in contact with a lever 24 fixed to the teak yoke shaft 8, and when the temperature is low, the bimetal 23 is activated. The spring force of the contraction acts to close the valve 10.

A pin 25 fixed to the yoke shaft 8 works in conjunction with an adjustment arm 26 of the yoke lever 18 to open the yoke valve 10.

FIG. 6 shows details of the interlocking part of the connecting rod 20.

A grommet 27 and a grommet 28 are provided at both ends of the connecting rod 20, and a long groove 29 is provided in the grommet 27 to form a gap e between it and the pin 12.
has been established. The thrust washers 30, 30' facilitate the sliding movement of the grommets 27, 28.

When the engine is started at low temperature, the engine's suction negative pressure is sucked into the diaphragm 1 and the stroke f
, and rotates the check lever 18 to open the check valve 10. The reaction force of spring 15 is binary 2
3, and when the reaction force of the bimetal 23 is strong, the spring 15 is deflected and the gap e is
Therefore, the opening of the check valve 10 becomes smaller.

As the engine warms up, the bimetal 23
is heated by the heater 22, and the reaction force that tends to close the expansion valve 10 becomes smaller.

At a certain point in time, the reaction force of the spring 16 becomes strong, the gap e disappears, and the opening of the choke valve 10 increases, resulting in a two-stage complete explosion opening.

Fine adjustment of the full explosion opening degree is done with β, and the difference between 1st and 2nd stage is determined by e. The play between the grommets 27 and 28 is absorbed by the spring 15. The reaction force of spring 15 can be adjusted using hole 1.
It can be corrected at position 9.

FIG. 7 is a detailed view of the connecting rod 20, in which hooks 32 and 33, which are made by bending rigid thin wire such as piano wire or stainless steel wire at both ends so as to surround the long groove 29 and hole 31, are attached to resin grommets 27 and 2, respectively.
8 and is integrally molded.

[Effects of the Invention] As explained above, according to the present invention, load fluctuations due to the seat of the two-stage switching spring and friction between the diaphragm rod and the diaphragm chamber are eliminated, and furthermore, the fluctuations due to vibration changes are eliminated. Since the generated inertia force is reduced, the external force applied between the bimetal and the two-stage switching spring can be eliminated, and the two-stage complete explosion of the automatic chyo-yoke device makes it possible to obtain the appropriate chyo-yoke valve opening depending on the warm-up of the engine. mechanism can be realized.

[Brief explanation of the drawing]

Fig. 1 shows the complete detonation mechanism of the prior art, Fig. 2 shows its connecting rod, Fig. 3 shows the complete detonation characteristics of the prior art and the present invention, and Fig. 4 is a side view of the embodiment of the present invention. , FIG. 5 is a plan view, FIG. 6 shows details of the interlocking part of the connecting rod, and FIG. 7 is a diagram showing the structure of the connecting rod. DESCRIPTION OF SYMBOLS 1...Diaphragm, 2...Guide, 3...Diaphragm chamber, 4...Spring, 5...Diaphragm rod, 6...Two-stage switching spring, 7...Chewing lever, 8...Chewy yoke shaft, 9... Connecting rod, 10... Chiyoke valve, 11...
... Conduit, 12, 12'... Pin, 13, 13'...
...Grommet, 14...Diaphragm rod, 1
5... Spring, 16... Hole, 18... Chain lever, 19... Hole, 20... Connecting rod,
21...Thermostat cover, 22...Heater, 23...Bimetal, 24...Lever, 25
... Pin, 26 ... Adjustment arm, 27 ... Grommet, 28 ... Grommet, 29 ... Long groove, 3
0,30'...Thrust washer, 31...Hole,
32, 33... Futsuku.

Claims (1)

[Claims] 1 A spring is interposed between a diaphragm operated by engine suction negative pressure and a chiyok lever that interlocks with the chiyoke valve, and the chiyoke valve is opened and closed by the displacement of the bimetal. In a two-stage complete explosion mechanism of an automatic choke device, the opening degree is controlled in two stages, and a diaphragm rod for connecting the diaphragm and a connecting rod is inserted into an opening provided in a diaphragm chamber for storing the diaphragm. , a tension spring for controlling two-stage switching of the choke valve is provided between the diaphragm rod and the choke lever, and the connecting rod for transmitting the movement of the diaphragm to the choke lever is formed of piano wire; Bend both ends of the piano wire into a hook shape, cover that portion with a grommet molded with resin, provide a pin that slides on the inner periphery of the grommet, and connect the piano wire to the piano wire via the pin, and A two-stage complete explosion mechanism for an automatic choke device, characterized in that the opening of the diaphragm chamber is configured to a size that does not make contact with the diaphragm rod.