JPS6137812Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an idling opening adjustment device for a sliding throttle valve type carburetor mainly applied to a vehicle engine.

Conventionally, this type of device has a stopper surface consisting of a downwardly inclined surface facing a screw for adjusting the throttle opening on the side surface of a slidable throttle valve in a guide cylinder extending upward from the carburetor body. A type of valve is known in which the valve is stopped at a position where the stopper surface contacts the screw when the valve is closed, and a predetermined idling opening position is obtained. is allowed to rotate more or less, causing the angular position to change, and is also allowed to be more or less tilted, causing it to fall down, which is disadvantageous in that its opening area tends to change more or less. More specifically, the throttle valve is prevented from rotating by engaging with the guide groove by the guide pin on the side, but it is rotatable within the range of the clearance, and the inner peripheral surface of the guide cylinder is formed on the outer periphery of the throttle valve. There is some clearance between them, and the screw can be tilted freely within that range, so that the angular position tends to change, and the pressing force of the screw acting on the stopper surface or further downstream thereof is likely to change. A relatively high negative pressure tends to cause collapse, which is accompanied by the above-mentioned disadvantages.

The present invention aims to provide a device free of such inconveniences, and includes a slidable throttle valve 3 fitted into a guide tube 2 extending upward from the carburetor body 1.
An axial guide groove 9 that engages with the guide pin 8 in the guide tube 2 and an obliquely downward facing screw 4 for adjusting the idling opening in the guide tube 2 are formed on both sides in the diametrical direction perpendicular to the intake flow. The stopper surface 5 is characterized in that the stopper surface 5 is configured as a compound slope surface that is also inclined obliquely in the front-rear direction of the intake air flow.

The throttle valve 3 has a cylindrical shape as a whole, has a spring 6 applied to its upper surface, and has a needle valve 7 extending downward, and is further prevented from rotating by a guide pin 8 on its side surface that engages with a guide groove 9. This point is not particularly different from the conventional one. According to the present invention, as described above, the stopper surface 5 is a compound inclined surface, that is, it is inclined diagonally downward and further inclined diagonally forward or obliquely backward in the front and rear direction of the intake flow. In this case, it is tilted forward, that is, slightly inclined toward the upstream side with respect to the flow of intake air in the carburetor main body 1. This angle of inclination is, for example, as shown by angle α in FIG. 2, and such a compound inclined surface can be easily obtained by, for example, single-angle milling. To explain its operation, consider the case where the throttle valve 3 is pushed down by the spring 6 and stops when it hits the screw 4 at the stopper surface 5. In this case, the screw 4 moves through the stopper surface 5. It acts to give the throttle valve 3 a pressing force in the horizontal direction, that is, a pressing force directed toward the downstream side of the flow of intake air, and a pressing force in the rotational direction, that is, a pressing force clockwise in FIG. The valve 3 is moved in one direction within each clearance and is always set at a predetermined angular position and at a predetermined inclination angle.
In other words, the idling opening of the engine is always maintained at a predetermined idling opening, thereby stabilizing the idling operation of the engine.

In this way, according to the present invention, the adjustment screw 4
The stopper surface 5, which is a diagonally downwardly inclined surface opposite to the stopper surface 5, is formed into a compound inclined surface that also slopes diagonally in the front-rear direction of the intake flow. As a result, it is not only pressed against the side surface inside the guide tube 2 facing the screw 4, but also pressed against the downstream side of the intake flow inside the guide tube 2, eliminating the degree of freedom due to the clearance and ensuring a stable position at all times. Thus, together with the negative suction pressure of the engine, the sealing performance is improved, and has the effect of making the supply of idle air-fuel mixture to the engine highly accurate.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of one example of the device of the present invention, FIG. 2 is a cross-sectional plan view thereof, FIG. 3 is a perspective view of the throttle valve, and FIG. 4 is a cross-sectional view taken along the line --. 1... Carburetor main body, 2... Guide tube, 3... Throttle valve, 4... Screw, 5... Stopper surface.

Claims (1)

[Scope of utility model registration request] A slidable throttle valve 3 fitted into a guide tube 2 extending upward from the carburetor main body 1 has an axial direction that engages with a guide pin 8 in the guide tube 2 on both diametrical sides perpendicular to the intake flow. A guide groove 9 and a stopper surface 5 consisting of a downwardly inclined surface facing the screw 4 for adjusting the idling opening in the guide tube 2, the stopper surface 5 is arranged diagonally also in the longitudinal direction of the intake flow. An idle opening adjustment device for a sliding throttle valve type carburetor, characterized in that it is configured with a complex inclined surface.