Patent ID: 11898615
Assignee: HITACHI ASTEMO, LTD.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  B | IPC B  F

Claim 0:
1. A cylinder apparatus comprising:
a first cylinder sealingly containing hydraulic fluid therein;
a first piston slidably fitted in the first cylinder and defining an inside of this first cylinder into a rod-side chamber and a bottom-side chamber;
an oil passage provided at the first piston and configured to establish communication between the rod-side chamber and the bottom-side chamber;
a disk valve configured to suppress a movement of the hydraulic fluid flowing in the oil passage to generate a damping force;
a piston rod coupled with the first piston;
a closing member provided on one end side of the first cylinder and configured to close the first cylinder with the piston rod inserted therethrough; and
a stopper mechanism configured to operate when the piston rod extends and moves toward an end portion inside the first cylinder,
wherein the stopper mechanism includes:
a second cylinder provided movably relative to the piston rod, the second cylinder including a bottom portion on the one end side of the first cylinder and a cylinder portion extending from the bottom portion toward the other end side of the first cylinder, at least a portion of an outer periphery of the second cylinder being configured to be slidably moved relative to the first cylinder; and
a second piston provided so as to be able to move along with a movement of the piston rod to be fitted to the second cylinder,

wherein a spring member is provided between the second cylinder and the closing member,
wherein a first communication passage is provided at the second cylinder, the first communication passage being configured to establish communication between an inside of the second cylinder and a chamber on the closing member side, the first communication passage being provided at the bottom portion, and
wherein a passage area variable mechanism is provided in the first communication passage, the passage area variable mechanism being configured to reduce a passage area of the first communication passage during an extension stroke of the piston rod and increase the passage area of the first communication passage during a compression stroke of the piston rod.