Variable back-up ring and a sealing structure having the same
View Patent ↗A sealing structure includes 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 and holding the O-ring. The variable back-up ring is deformable in a radial direction depending on a magnitude of a fluid pressure applied between the first connector body and the second connector body.
1. 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 and holding the O-ring,
wherein the variable back-up ring is deformable in a radial direction depending on a magnitude of a fluid pressure applied between the first connector body and the second connector body,
wherein the back-up ring includes a first half shell extending in an annular shape, a second half shell symmetrically connected to the first half shell, and an inner cavity defined by the first half shell and the second half shell, and
wherein the inner cavity is a closed cavity.
2. The sealing structure according to claim 1 , 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
a position of the outer circumferential surface of the variable back-up ring is variable in a radial direction of the variable back-up ring depending on the magnitude of the fluid pressure.
3. The sealing structure according to claim 2 , wherein a 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.
4. The sealing structure according to claim 1 , 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;
the O-ring is relatively close to the first side; and
the variable back-up ring is relatively close to the second side.