Dual-piston valve unit for bicycle anti-lock braking systems

Abstract

The dual-piston valve unit (20) for the bicycle anti-lock brake system comprises an outer valve body (21) having an axially elongated inner cavity (22), in which a main piston valve member (23) slides, separating the upstream chamber (25) and the downstream chamber (24). The main piston valve member (23) forms an internal axial channel (40), in which a secondary piston valve member (41) slides. An electric motor (28) simultaneously linearly displaces the main piston valve member (23) and the secondary piston valve member (41) in opposite axial directions. During use, the upstream chamber (25) is in fluid communication with the master cylinder operated by the rider. The volume of brake fluid in the upstream chamber (25) is kept constant, so the rider does not feel the ABS system operating when squeezing the brake lever.

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