Patent ID: 8657140
Filing Date: 2014-02-25
Classification: B60K

Abstract:
1. A filler cap for a fuel tank, wherein the filler cap is attached to a filler opening of a fuel tank, and arranged with an air passage channel to connect between inside and outside the fuel tank in a cap main body comprised of an outer cap and an inner cap and with a valve mechanism portion in this air passage channel; wherein, the valve mechanism portion comprises: a cylinder main body arranged with a first space of a columnar shape arranged almost at a center position of an inner plane of the inner cap so as to be connected to inside the fuel tank, a second space of a columnar shape having a smaller diameter than the first space and arranged so as to be connected to the first space, and a third space arranged so as to be connected to this second space and at the same time to outside the fuel tank, a valve-body-supporting member arranged in the first space with a large diameter portion so as to form a connection channel to inside the fuel tank and with a small diameter portion having a smaller outer diameter than the large diameter portion and arranged on an upper plane of the small diameter portion with an air passage channel connected to this connection channel, and a valve body formed of a non-air-permeable, elastic material having a thin form with elasticity and flexibility, and also having a circular plain view with a larger diameter than the small diameter portion of the valve-body-supporting member, wherein the valve body is put on the small diameter portion with a peripheral edge part of the valve body being slightly apart from a first surface that is slanted upward so as to connect between a second surface to form the second space of the cylinder main body and a third surface to form the third space, and at the same time, a central part of the valve body under the state of putting on in a manner as mentioned above is facing to the third space; wherein, when a pressure inside the fuel tank is increased by a vaporized gas evaporated from a fuel in the fuel tank, the valve body moves upward by the vaporized gas via the air passage channel and the connection channel between inside the fuel tank and the valve-body-supporting member so that a peripheral part of the valve body may contact to the first surface of the cylinder main body thereby shutting down the connection between the second space and the third space, when the pressure inside the fuel tank is further increased above a pressure for a deformation strength prescribed to the valve body, a central part of the valve body moves upward further and enters into the third space thereby causing deformation so as to shorten the outer diameter of the valve body to form wrinkles; and as a result, in the peripheral part of the valve body are formed a portion contacting to a lower end of the third surface to form the third space of the cylinder main body and a concave portion not contacting thereto, and consequently, the second space and the third space are connected via a space of this concave portion to release an excessive pressure to outside the fuel tank thereby bringing the pressure inside the fuel tank to lower than the pressure for the deformation strength, and when the pressure inside the fuel tank becomes negative by consumption of the fuel inside the fuel tank under the state that a fluid pressure of the fuel is acting to the valve body, the peripheral part of the valve body is sucked toward the fuel tank by this negative pressure whereby the peripheral part of the valve body hangs down by using an upper peripheral edge part of the small diameter portion of the valve-body-supporting member as a pivot point thereby enlarging a gap between the first surface of the cylinder main body and the valve body so as to connect between the second space and the third space thereby introducing an atmospheric air into the fuel tank so as to bring the state of an atmospheric pressure; whereby functioning as a safety valve as well as a one-way valve.