HYDRAULIC FLUID RESERVOIR AND HYDRAULIC PRESSURE CONTROL UNIT

摘要

A piston 74 is guided by a two-point guide thus allowing a working liquid to smoothly flow into or flow out from a liquid chamber 82. The liquid chamber 82 is formed into a donut shape and an opening of a passage of the working liquid is arranged at a center portion of the donut. The piston 74 adopts the stepped structure which has a large-diameter portion 74L and a small-diameter portion 745. The large-diameter portion 74L is fitted into a cylinder bore 560 and a small-diameter portion 74S is fitted into a second cylinder bore 562. The working liquid flows into or flows out from the hydraulic chamber 82 through groove passages 90 formed on an outer periphery of the small-diameter portions 74S.