Damper
A damper includes a piston and a cylinder housing the piston, and generates a braking force based on a movement or relative movement of the piston. The piston includes a trunk portion and a seal ring surrounding the trunk portion. A first seal portion against an inner wall of the cylinder is formed on an outer peripheral portion in the seal ring, and a second seal portion against a circumference wall portion projecting from the trunk portion is formed in a front end portion positioned on a pressure chamber side. Also, a support rib portion is provided outside the trunk portion, which allows the seal ring to move within a predetermined range along a moving direction of the piston in a state wherein a movement gap for a fluid is formed between the trunk portion and an inner peripheral portion of the seal ring.
1. A damper comprising a piston and a cylinder housing the piston, and generating a braking force based on a movement or relative movement of the piston,
wherein the piston includes a trunk portion and a seal ring surrounding the trunk portion, and
the trunk portion includes:
a circumference wall portion projecting from an outer surface of the trunk portion and formed on a pressure chamber side,
a plurality of support rib portions projecting radially outwardly from the outer surface along a moving direction of the trunk portion and spaced from each other in a circumferential direction of the trunk portion to form spaces therebetween in the circumferential direction, and
movement control portions projecting radially outwardly from ends of the support rib portions, so that a movement of the seal ring within a predetermined range along the moving direction of the piston is made in a state wherein movement gaps for a fluid are formed between the trunk portion and an inner peripheral portion of the seal ring by the support rib portions and the movement control portions.
2. A damper according to claim 1 , wherein front ends of the support rib portions positioned on a pressure chamber side are integrated with the circumference wall portion.
3. A damper according to claim 1 , wherein the seal ring includes a circumference projecting portion projecting backwardly from a base portion positioned on a pressure chamber side, wherein an outer peripheral portion on a projecting end side thereof is a first seal portion against an inner wall of the cylinder.
4. A damper according to claim 3 , wherein the seal ring further includes an inner circumference projecting portion projecting backwardly from the base portion inside the circumference projecting portion, wherein a projecting end side thereof is a sliding contact portion against the support rib portions.
5. A damper according to claim 4 , wherein a projecting size from the base portion of the circumference projecting portion is larger than a projecting size form the base portion of the inner circumference projecting portion.
6. A damper according to claim 3 , wherein a second seal portion is formed by a circumference projecting piece formed in a front end portion of the seal ring.
7. A damper comprising a piston and a cylinder housing the piston, and generating a braking force based on a movement or relative movement of the piston,
wherein the piston includes a trunk portion and a seal ring surrounding the trunk portion, and
the trunk portion includes:
a circumference wall portion projecting from an outer surface of the trunk portion and formed on a pressure chamber side,
a plurality of support rib portions projecting radially outwardly from the outer surface along a moving direction of the trunk portion and spaced from each other in a circumferential direction of the trunk portion to form spaces therebetween in the circumferential direction, and
movement control portions projecting radially outwardly from ends of the support rib portions, so that a movement of the seal ring within a predetermined range along the moving direction of the piston is made in a state wherein movement gaps for a fluid are formed between the trunk portion and an inner peripheral portion of the seal ring by the support rib portions and the movement control portions,
wherein the seal ring includes a circumference projecting portion projecting backwardly from a base portion positioned on a pressure chamber side, wherein an outer peripheral portion on a projecting end side thereof is a first seal portion against an inner wall of the cylinder,
wherein the seal ring further includes an inner circumference projecting portion projecting backwardly from the base portion inside the circumference projecting portion, wherein a projecting end side thereof is a sliding contact portion against the support rib portions,
wherein a projecting size from the base portion of the circumference projecting portion is larger than a projecting size form the base portion of the inner circumference projecting portion, and
wherein the inner circumference projecting portion is located between the circumference wall portion and the movement control portions, and an end portion of the circumference projecting portion away from the base portion is located outside the movement control portions.
8. A damper according to claim 1 , wherein the trunk portion further includes a circumference outer flange spaced from the circumference wall portion in the moving direction, the movement control portions being provided on the circumference outer flange.