VARIABLE BACK-UP RING AND A SEALING STRUCTURE HAVING THE SAME
A variable back-up ring includes: a first half shell; a second half shell having a symmetrical shape to the first half shell; and an inner cavity defined by the first half shell and the second half shell. The first half shell and the second half shell are deformable depending on a magnitude of a fluid pressure acting on the first half shell and the second half shell.
1 . A variable back-up ring, comprising:
a first half shell;
a second half shell having a symmetrical shape to the first half shell; and
an inner cavity defined by the first half shell and the second half shell,
wherein the first half shell and the second half shell are deformable depending on a magnitude of a fluid pressure acting on the first half shell and the second half shell.
2 . The variable back-up ring according to claim 1 , wherein the first half shell and the second half shell have a reference shape when the fluid pressure is lower than a reference pressure, and
wherein the reference shape is a shape in which the first half shell and the second half shell contract radially inward.
3 . The variable back-up ring according to claim 1 , wherein the first half shell and the second half shell have an expanded shape when the fluid pressure is higher than a reference pressure, and
wherein the expanded shape is a shape in which the first half shell and the second half shell expand radially outward.
4 . The variable back-up ring according to claim 2 , wherein the shape of the first half shell and the second half shell varies between the reference shape and an expanded shape as the magnitude of the fluid pressure varies.
5 . A sealing structure, comprising:
a first connector body having a groove;
a second connector body encompassing the first connector body;
an O-ring partially received in the groove of the first connector body; and
a variable back-up ring partially received in the groove of the first connector body, holding the O-ring, the variable back-up ring being deformable in a radial direction depending on a magnitude of a fluid pressure applied between the first connector body and the second connector body.
6 . The sealing structure according to claim 5 , wherein the variable back-up ring includes an inner circumferential surface contacting the groove of the first connector body and an outer circumferential surface facing an inner circumference of the second connector body, and
wherein a position of the outer circumferential surface of the variable back-up ring is variable in the radial direction of the variable back-up ring depending on the magnitude of the fluid pressure.
7 . The sealing structure according to claim 5 , wherein the shape of the variable back-up ring is variable so that the outer circumferential surface of the variable back-up ring is brought into contact with the inner circumference of the second connector body when the magnitude of the fluid pressure is higher than a reference pressure.
8 . The sealing structure according to claim 5 , wherein the groove of the first connector body includes a base surface recessed radially inward from an outer circumference of the first connector body, a first side relatively close to a source of the fluid pressure, and a second side opposing the first side,
wherein the O-ring is relatively close to the first side, and
wherein the variable back-up ring is relatively close to the second side.