Patent ID: 9074650
Filing Date: 2015-07-07
Classification: F16F

Abstract:
1. A piston assembly of a shock absorber provided on a vehicle, the piston assembly comprising: a piston body provided with a center penetrated by a piston rod reciprocating in a cylinder and a repetitive pattern in which a compression fluid passage having an inlet at a lower end thereof and a tension fluid passage having an inlet at an upper end thereof alternately penetrate the piston body, wherein the inlets of the compression fluid passage and the tension fluid passage have larger cross-sectional areas than corresponding outlets of the compression fluid passage and the tension fluid passage, and the compression fluid passage and the tension fluid passage are kept open; a compression retainer seated at an upper portion of the piston body and penetrated by a connection hole corresponding to the compression fluid passage; a tension retainer seated at a lower portion of the piston body and penetrated by a connection hole corresponding to the tension fluid passage; and a seating unit formed between the compression retainer and the piston body and between the piston body and the tension retainer to determine positions at which the compression retainer and the tension retainer are coupled to the piston body, wherein the seating unit comprises: a first seating assembly provided at an edge of a first rod hole formed at a center of the piston body and penetrated by the piston rod and at an edge of a second rod hole formed at a center of the compression retainer and penetrated by the piston rod, the edge of the second rod hole facing the edge of the first rod hole; and a second seating assembly provided at the edge of the first rod hole and at an edge of a third rod hole formed at a center of the tension retainer and penetrated by the piston rod, the edge of the third rod hole facing the edge of a first rod hole, and wherein: a contact surface of the compression retainer arranged between the second rod hole and the connection hole of the compression retainer to adjoin the piston body is provided with a raised step protruding toward the piston body to have a stepped shape; and a contact surface of the tension retainer arranged between the third rod hole and the connection hole of the tension retainer to adjoin the piston body is provided with a raised step protruding toward the piston body to have a stepped shape, wherein the first seating assembly comprises: at least one first protrusion protruding from the edge of the first rod hole toward the compression retainer; a first ring groove depressed along the edge of the second rod hole to accommodate the first protrusion; and a plurality of first auxiliary protrusions arranged along the first ring groove to be spaced apart from each other by a distance corresponding to a distance between both ends of the first protrusion and protruding toward the piston body.