The principle of operation is as simple as it is effective. Inside the pump there is a shaft (whose diameter can be varied if necessary), which is directly connected to the brake pedal by means of a rod. The pumping element is mounted on the shaft, a sort of ring whose function is pushing the oil into the system circuit and directing it to the caliper. Once the brake is pressed, the flow of the oil is immediate, given the absence of play and friction present in the pumps with leverage. The intensity of the braking effect is directly related to the size of the shaft you decide to mount. In fact, the volume of oil that the flange pushes is obtained from the difference between the total volume of the internal chamber of the brake master cylinder and its volume. With the same flange, therefore, if the diameter of the rod is increased, the volume of oil to be moved is reduced and the pressure generated by the system increases. In other words, by applying the same force to the brake pedal, a rod with a larger diameter allows for greater braking power.
In the above interactive animation you can see the operation of the Italfreno pump. In the first part of the animation it is possible to see how an internal shaft with a smaller diameter exerts an X force. In the second part of the animation, however, it is shown how, as the diameter of the stem increases, the pressure generated in the system with the same force exerted on the pedal.
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