Ngk Spark Plug Company, Limited

Toshiya Oya

Seiji Oya

Tatsuya Suzuki

Toshinori Nishi

Akio Mori

A temperature sensor () including: a temperature sensing element () including a temperature sensing portion () having an electrical characteristic which varies depending on temperature, and an electrode wire () for outputting an electrical signal from the temperature sensing portion (); and a sheath core wire (signal wire) () electrically connected to the electrode wire (). The electrode wire () is formed from a platinum-palladium-rhodium alloy containing Pt, Pd and Rh. The alloy contains a total of 0.1 to 1.2 mol % of at least one alkaline-earth metal selected from the group consisting of Ca, Sr and Ba; 0.1 to 43.0 mol % of Pd; and 1.0 to 43.0 mol % of Rh, and the balance is Pt and incidental impurities. In the platinum-palladium-rhodium alloy, second-phase precipitated grains mainly containing Pt, Pd and the alkaline-earth metal are dispersed in a matrix phase.

Temperature sensor

A temperature sensor includes: a temperature sensing element including a temperature sensing portion, electrical characteristics of which vary depending on temperature, and an electrode wire for outputting an electric signal from the temperature sensing portion to the outside; and a sheath core wire (signal wire) electrically connected to the electrode wire. The electrode wire is made of a platinum-rhodium alloy. The platinum-rhodium alloy is composed of 0.1 to 1.5 mol % of Sr, 22 to 40 mol % of Rh, and a remainder composed of Pt and unavoidable impurities. The platinum-rhodium alloy has a second-phase mainly composed of Sr and Pt whose precipitated grains are dispersed in a matrix phase. An area ratio of the second phase at a cross section is not greater than 25%.

A temperature sensor includes a temperature sensitive element, a sheath portion, a surrounding portion, and a holding member. This temperature sensor has a void formed forward of a temperature sensitive body. When the void is projected in an axial direction of the surrounding portion from a forward end side of the surrounding portion, the void contains at least a forward end surface of the temperature sensitive body.

Temperature sensor with improved sheath

A temperature sensitive element in a temperature sensor includes a covering member formed from alumina and aluminosilicate glass, and the volume ratio of the alumina to the aluminosilicate glass (the alumina/the aluminosilicate glass) in the covering member is 30 vol %/70 vol %. The aluminosilicate glass contained in the covering member is high heat-resistant glass having a softening point of 900&#xb0; C. or higher. The covering member can hold output lines and pads and can restrain separation of the output lines from the pads and separation of the pads from a ceramic substrate even in an environment of higher temperature as compared with the case where the covering member is formed of the aluminosilicate glass only.

Temperature sensitive element and temperature sensor

In a temperature sensitive element, a covering member containing a glass as a main component and having a thermal expansion coefficient smaller than that of output lines is provided on pads to cover at least portions of output lines located on the pads. The pads are formed of a glass-based material which contains, as main components, a metal and a glass having a thermal expansion coefficient smaller than that of a ceramic substrate, and the thermal expansion coefficient of the pads is set to be smaller than that of the output lines. Accordingly, in the case where the temperature sensitive element is exposed to a temperature change between a high temperature and ordinary temperature, compressive stress can be applied to the output lines by the covering member and the pads. Thus, the fixing force between the output lines and the pads can be increased.

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Nagoya, Japan

Toshiya Oya