Cylinder device and manufacturing method therefor

A cylinder device, comprising:

• a cylinder in which working fluid is sealed;
• a piston that is fit-inserted to be slidable in the cylinder and divides an inside of the cylinder;
• a piston rod that is coupled to the piston;
• a rod guide for guiding the piston rod in a slidable manner by allowing the piston rod to be inserted through the rod guide, the rod guide being mounted to the cylinder;
• and
• a locking mechanism that is actuated when the piston rod extends to reach a full extension position of the cylinder,
• wherein the locking mechanism comprises:
• a lock piston that is provided on the piston rod on the rod guide side with respect to the piston;
• and
• a lock cylinder portion that is provided in the cylinder on a projecting end side of the piston rod and is provided to allow the look piston to be slidably inserted through the look cylinder portion,
• wherein the lock piston comprises:
• a flow path limiting-opening mechanism for limiting a flow path when the lock piston moves into the lock cylinder portion, and opening the flow path when the lock piston moves out of the lock cylinder portion;
• a piston-side fixing portion for supporting the flow path limiting-opening mechanism from the piston side, the piston-side fixing portion being provided on an outer peripheral side of the piston rod;
• and
• an annular rod-guide-side fixing member for restricting the flow path limiting-opening mechanism from moving to the rod guide side, the annular rod-guide-side fixing member being fitted in a groove that is formed along the piston rod, and
• wherein the annular rod-guide-side fixing member comprises a radially shrinkable and expandable ring made of a metal material, the radially shrinkable and expandable ring being inserted along the piston rod with a gap on an inner peripheral side of the radially shrinkable and expandable ring, and being fitted into the groove by being pressed in a radial direction.

A manufacturing method for a cylinder device, the cylinder device comprising:

• a cylinder in which working fluid is sealed;
• a piston that is fit-inserted to be slidable in the cylinder and divides an inside of the cylinder;
• a piston rod that is coupled to the piston;
• a rod guide for guiding the piston rod in a slidable manner by allowing the piston rod to be inserted through the rod guide, the rod guide being mounted to the cylinder;
• and
• a locking mechanism that is actuated when the piston rod extends to reach a full extension position of the cylinder,
• the locking mechanism comprising:
• a lock piston that is provided on the piston rod on the rod guide side with respect to the piston;
• and
• a lock cylinder portion that is provided in the cylinder on a projecting end side ox the piston rod and is provided to allow the lock piston to be slidably inserted through the lock cylinder portion,
• the lock piston comprising:
• a flow path limiting-opening mechanism for limiting a flow path when the lock piston moves into the lock cylinder portion, and opening the flow path when the lock piston moves out of the lock cylinder portion;
• a piston-side fixing portion for supporting the flow path limiting-opening mechanism from the piston side, the piston-side fixing portion being provided on an outer peripheral side of the piston rod;
• and
• an annular rod-guide-side fixing member for restricting the flow path limiting-opening mechanism from, moving to the rod guide side, the annular rod-guide-side fixing member being fitted in a groove that is formed along the piston rod, the manufacturing method for the cylinder device comprising:
• fixing the piston-side fixing portion to the piston rod after inserting the piston-side fixing portion from the piston side;
• mounting the flow path limiting-opening mechanism, after inserting the flow path limiting-opening mechanism from the rod guide side;
• and
• fixing the annular rod-guide-side fixing member by fitting the annular rod-guide-side fixing member into the groove after inserting the annular rod-guide-side fixing member from the rod guide side.