How does the accelerator pedal control the accelerator through the cable? Why does the throttle opening change when stepping on the pedal?

One end of the accelerator cable is installed on the semi-circular wheel, the cable sheath is fixed with the carburetor, the throttle valve and the semi-circular wheel are installed on the same shaft, and the other end of the accelerator cable is fixed on the cab floor. When the foot steps on the accelerator pedal, the accelerator cable drives the semi-circular wheel to rotate, and the semi-circular wheel rotates with the accelerator shaft, thus opening the throttle valve, and changing the opening of the throttle valve by changing the distance of the accelerator pedal. When the foot leaves the accelerator pedal, the throttle valve is closed under the action of the return spring. Although there is no integral reward, I am still willing to answer your question.