Patent ID: 9151256
Filing Date: 2015-10-06
Classification: B60K,F02M,F16K

Abstract:
1. An overfill prevention valve disposed in an evaporant line of a fuel tank device, the fuel tank device comprising a full-tank regulation valve which closes an outlet of fuel vapor when a fuel level reaches a predetermined height at a refueling time, and the evaporant line through which an inside of a fuel tank communicates with an outside canister, the overfill prevention valve including: a valve housing comprising: a parent valve which is disposed slidably within the valve housing so as to come close to and go away from the first valve seat and the second valve seat, and which includes an internal space within which the parent valve is disposed, the parent valve including: a first urging unit which urges the parent valve toward the first valve seat; a child valve which is disposed slidably within the parent valve so as to come close to and go away from the third valve seat; a second urging unit which is disposed within the parent valve and which urges the child valve toward the third valve seat; and an air passage forming unit which forms an air passage between the parent valve and the first valve seat when the parent valve abuts on the first valve seat, wherein an urging force of the first urging unit and an urging force of the second urging unit are set such that: in a first state where an internal pressure of the fuel tank is lower than a first predetermined value, the parent valve abuts on the first valve seat due to the urging force of the first urging unit, and the child valve abuts on the third valve seat due to the urging force of the second urging unit; in a second state where the internal pressure of the fuel tank exceeds a second predetermined value which is higher than the first predetermined value, the parent valve slides against the urging force of the first urging unit and abuts on the second valve seat, and the child valve goes away from the third valve seat against the urging force of the second urging unit; and in a third state where the internal pressure of the fuel tank becomes lower than the second predetermined value but is still higher than the first predetermined value, a valve opening pressure of the child valve from the third valve seat is higher than a valve opening pressure of the parent valve from the second valve seat, so that the child valve abuts on the third valve seat due to the urging force of the second urging unit during when the parent valve is abutting on the second valve seat.