Nippon Seiki Co., Ltd.

Kiyoshi Enomoto

Koichi Sato

Yoshiyuki Shimazaki

Tadao Nakagawa

Yoshihiro Kamimura

Shigeki Koide

Tetsuya Sato

Toshio Hayakawa

Tetsuya Satoh

The present invention provides a liquid surface detection devicein which corrosion is restrained even when liquid having conductivity is used so that a longer lifespan is achieved, including a liquid surface detection sensorthat outputs a signal indicating a variation in liquid level as a variation in resistance value by the sliding movement of a contact pointon an electrode connected to a resistor, and a control unitthat controls supply and stops a supply of electric power to the liquid surface detection sensorat predetermined intervals, in which a vehicle state determination unit that determines a state of a vehicle is provided and the control unitcontrols the duration to stop the supply of electric power to the liquid surface detection sensorwhen the vehicle state determination unit determines that the vehicle is in a traveling state.

Liquid surface detection device

The present invention provides an inexpensive small-sized liquid level detector. A liquid level detectorincludes a float moving in accordance with variations in liquid level, a hard circuit board, resistorsandprovided on the circuit board, a first sliding pathmade of a plurality of electrodesprovided on the circuit boardand connected to the resistorsand, and a first contactcoming into contact with the first sliding path, and the liquid level detectoroutputs an electrical signal based on the resistances of the resistorsandwhich are varied by the first contactcoming into contact with at least one of the plurality of electrodesforming the first sliding pathin accordance with a variation of the float. A second sliding pathelectrically connected to the first sliding pathis provided on the circuit board, a second contactcoming into contact with the second sliding pathis provided, and each of the first and second contactsandis electrically connected to an external circuit.

Liquid level detector

A liquid level detecting apparatus resistant to the deterioration and corrosion thereof is provided while holding down an increase in the manufacturing cost thereof. This apparatushas fixed electrodeson which a sliding contact pointis slidingly moved in accordance with a fluctuation of a float, and a first resistorconnected to the fixed electrodes, the fixed electrodesbeing made of at least silver (Ag), palladium (Pd) and a glass component, a weight ratio of the silver (Ag) to palladium (Pd) being not lower than 75 wt. % to not higher than 25 wt. %, a sliding portionof the fixed electrodeson which the sliding contact pointis slidingly moved being covered with second resistorsa resistance value of which is lower than that of the first resistor

Liquid level sensor

A resistance-type liquid level measuring apparatus which suppresses a detection voltage error due to silver sulfide within a permissible range in practical use and enables measurement indication with accuracy, and comprises a resistance-type sensor including a float floating according to a liquid level, an insulating substrate having a plurality of conductor electrodes connected with a resistor , and a movable contact interlocked with a movement of the float to come in contact with the conductor electrodes on the insulating substrate , in which a material containing silver is used as a material of the conductor electrodes or the movable contact, a voltage dividing resistance is connected with a power source BA in series with the resistor , and a voltage of a connection point between the voltage dividing resistance and the resistor is outputted as a signal corresponding to the liquid level, and resistance values of the voltage dividing resistance and the resistor are set so that a voltage drop VS due to silver sulfide generated between the conductor electrode and the movable contact becomes % or less, preferably % or less with respect to a difference between a voltage VF equivalent to a full tank of the liquid level and a voltage VE equivalent to a low region.

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Niigata, Japan

Kiyoshi Enomoto