TECHNICAL FIELD

The disclosure in this specification relates to a ventilation control valve for a fuel tank.

BACKGROUND ART

A float valve is used for a refueling control valve which is one application. The refueling control valve is also called a full tank control valve for controlling a full tank (state in which the fuel has been supplied to an upper limit of the fuel tank). When a liquid level reaches the float, this device closes the passage by the float floating on the fuel. When the passage is closed, a liquid level in the filler pipe rises and an automatic cut function of a refueling gun is promoted.

SUMMARY

This disclosure provides a ventilation control valve for a fuel tank disposed in a ventilation passage communicating an inside and an outside of a fuel tank. A ventilation control valve for a fuel tank, comprising: a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state; a volume chamber in which volume changes in accordance with a vertical movement of the float; and a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state, wherein the volume chamber includes: a fixed piston disposed on a case; and a movable cylinder disposed on the float and movably accommodating the fixed piston. The volume chamber includes a fixed piston disposed on the case and a movable cylinder disposed on the float and movably accommodating the fixed piston.

According to a disclosed ventilation control valve for a fuel tank, the volume chamber functions as a damper that regulates a valve closing motion and/or valve opening motion by the float. The flow rate adjusting mechanism sets the outflow of the fluid from the inside to the outside of the volume chamber into the first state and sets the inflow from the outside to the inside into the second state different from the first state. The volume chamber has a fixed piston disposed on the case and a movable cylinder disposed on the float and accommodating the fixed piston so as to be relatively movable. As a result, the volume chamber that functions as a damper that restricts the movement of the float is formed.

This disclosure provides a ventilation control valve for a fuel tank disposed in a ventilation passage communicating an inside and an outside of a fuel tank. A ventilation control valve for a fuel tank, comprising: a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state; a volume chamber in which volume changes in accordance with a vertical movement of the float; and a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state, wherein a gas reservoir which stores gas; and a through hole which penetrates from the gas reservoir to the volume chamber and supplies the gas from the gas reservoir to the volume chamber.

According to a disclosed ventilation control valve for a fuel tank, the volume chamber functions as a damper that regulates a valve closing motion and/or valve opening motion by the float. The flow rate adjusting mechanism sets the outflow of the fluid from the inside to the outside of the volume chamber into the first state and sets the inflow from the outside to the inside into the second state different from the first state. Since the gas reservoir stores the gas, even if the liquid enters into an inside of the float, a buoyancy of the float is compensated by supplying the gas from the through hole. Therefore, a damper action is given to the valve opening motion without impairing the responsiveness of the valve closing motion.

This disclosure provides a ventilation control valve for a fuel tank disposed in a ventilation passage communicating an inside and an outside of a fuel tank. A ventilation control valve for a fuel tank, comprising: a valve mechanism which has a float being capable of floating and moving up and down on a liquid level of a fuel, and which switches a passage cross sectional area of the ventilation passage in conjunction with the float into an open state and a restricted state in which the passage cross sectional area is restricted than the open state; a volume chamber in which volume changes in accordance with a vertical movement of the float; and a flow rate adjusting mechanism which sets an outflow of a fluid from an inside to an outside of the volume chamber in a first state, and which sets an inflow from the outside to the inside in a second state different from the first state.

According to a disclosed ventilation control valve for a fuel tank, the ventilation passage is provided with a valve mechanism. The valve mechanism performs a valve opening motion and a valve closing motion. The valve mechanism is provided with a volume chamber and a flow rate adjusting mechanism. The float provides a valve closing motion and a valve opening motion by moving up and down. The volume chamber functions as a damper that regulates the movement of the float. Therefore, the volume chamber functions as a damper that regulates the valve closing motion and/or the valve opening motion of the float. The flow rate adjusting mechanism sets the flow of the fluid from the inside of the volume chamber to the outside to a first state and sets the flow from the outside to the inside to a second state different from the first state. For example, the flow rate adjusting mechanism adjusts the valve closing motion and/or the valve opening motion slower. When the valve closing motion is adjusted slower, the energy at the time of valve closing is suppressed. When the valve opening motion is adjusted slower, a stroke amount for valve opening can be suppressed without impairing the responsiveness of the valve closing motion, and the energy at the next valve closing is suppressed. As a result, it is possible to prevent an undesirable collision.

The disclosed aspects in this specification adopt different technical solutions from each other in order to achieve their respective objectives. Reference numerals in parentheses described in claims and this section exemplarily show corresponding relationships with parts of embodiments to be described later and are not intended to limit technical scopes. The objects, features, and advantages disclosed in this specification will become apparent by referring to following detailed descriptions and accompanying drawings.

