Patent ID: 8752682

Claim:
A piston assembly of a shock absorber, comprising: a piston body penetrated at a central portion thereof by a piston rod which reciprocates within a cylinder of the shock absorber, and a plurality of compression passages and a plurality of rebound passages alternately penetrating the piston body are formed around the piston rod; a compression retainer placed over the piston body, in which a plurality of connection holes corresponding to the compression passages penetrate the compression retainer; and a rebound retainer placed under the piston body, in which a plurality of connection holes corresponding to the rebound passages penetrate the rebound retainer, wherein a lower end of a compression passage is an inlet; an upper end of a rebound passage is an inlet; and cross-sectional areas of the inlets of the compression passage and the rebound passage are larger than cross-sectional areas of outlets of the compression passage and the rebound passage, wherein the compression retainer comprises a step-shaped protrusion squared out therefrom, which is inserted into an inlet of at least one rebound passage among the plurality of rebound passages.