| 摘要 |
PURPOSE:To obtain a constant vacuum type carburetor capable of smoothly operating by providing a disklike sliding throttle valve on the variable piston side of a constant vacuum type carburetor, and further constituting the sliding throttle valve with two sheets of main-and sub-valves, and making the subthrottle valve movable to the direction of suction air flow. CONSTITUTION:On the side surface on the engine side of a variable piston 24 which moves up and down introducing the vacuum pressure of a venturi part V into a chamber 28, a disklike main throttle valve 19 which is moved up and down by a lever, and a subthrottle valve 20 which is integrally moved up and down together with the main throttle valve 19 on the engine side by means of the main throttle valve 19 are provided. Between the main throttle valve 19 and the subthrottle valve 20, a pressure receiving chamber 22 into which the negative pressure at the downstream side of the throttle valve is introduced is provided. When the throttle valve moves up and down, even if the valve is attracted by the negative pressure of intake air to cause a large friction resistance, the negative pressure is introduced into the pressure receiving chamber 22 to retract the subthrottle valve, and accordingly the friction force is lessened to operate the throttle valve smoothly.
|
