Ngk Spark Plug Company, Limited

Yoshihito Ikai

Yutaka Sekiguchi

Takeshi Mitsuoka

Hiroki Takeuchi

Ryo Suzuki

Yutaka Yokoyama

Masayuki Segawa

Yosuke Yatsuya

Koji Funaki

Toshiyuki Sakurai

Saori Narita

A ceramic heater includes a substrate containing a ceramic, and a resistor containing another ceramic and embedded in the substrate. The resistor includes two lead portions, a joint portion that connects the two lead portions, an electrode portion formed integrally with at least one lead portion, having one end portion connected to the one lead portion, extending in a direction crossing an axis of the one lead portion, and having the other end portion exposed at the surface of the substrate. In a cross section of the electrode portion taken along an imaginary plane passing through the axis of the one lead portion and parallel to an extending direction of the electrode portion, 0.1&#x2264;A/B&#x2264;0.8 is satisfied, where A is the length of the other end portion parallel to the axis, and B is the length of the one end portion parallel to the axis.

Ceramic heater and glow plug

A ceramic heater includes a substrate containing a ceramic, and a resistor containing another ceramic and embedded in the substrate. The resistor includes two lead portions, a joint portion connecting the two lead portions, and an electrode portion formed integrally with at least one lead portion and extending in a direction crossing an axial line of the one lead portion. The electrode portion has a base end portion connected to the one lead portion, a distal end portion exposed at an outer surface of the substrate, and a connection portion disposed between the base end portion and the distal end portion and connecting the base end portion and the distal end portion together. A cross section of either the base end portion, the distal end portion, and the connection portion has an imaginary plane perpendicular to an extension direction of the electrode portion and has a streamline shape.

A ceramic heater wherein in at least one cross section of the ceramic heater orthogonal to the axial direction, a first resistor cross section has no protrusion on a first inner portion of the contour of a first resistor cross section, and has two or more protrusions on a first outer portion of the contour of the first resistor cross section and a method of manufacturing the ceramic heater.

Ceramic heater, glow plug, method of manufacturing ceramic heater and method of manufacturing glow plug

A ceramic heater elementincludes an insulating substrate, and a heating resistorembedded in the insulating substrate. The insulating substratecontains a main phase formed of &#x3b2;-SiAlON or a multiphase SiAlON of &#x3b2;-SiAlON and &#x3b1;-SiAlON; a grain boundary phase containing a rare earth element; and a silicide of at least one species selected from among Cr, W, Mo, V, and Fe. The heating resistorcontains a main phase formed of an electrically conductive compound containing at least one species selected from among silicide, nitride, and carbide of Mo, and silicide, nitride, and carbide of W; &#x3b2;-SiAlON or a multiphase SiAlON of &#x3b2;-SiAlON and &#x3b1;-SiAlON; and a grain boundary phase containing a rare earth element.

Ceramic heater element, ceramic heater, and glow plug

A ceramic heater () includes a substrate () and a resistor element () buried in the substrate (). The resistor element () includes a heat-generating portion (), lead portions (), and intermediate portions () located between the heat-generating portions () and the lead portions (). The intermediate portions () are formed such that, when cross sections at arbitrary two points Pand Palong the axis XA direction are compared, both the diameter CL of an imaginary circumscribed circle CG containing cross sections of the resistor elementand the total cross sectional area HS of the cross sections become small in the front end side cross section as compared with those in the rear end side cross section.

Disclosed is a ceramic heater capable of preventing failures due to the thermal stress, such as cracks, and corrosion by a calcium component. The ceramic heater has a heating element including at least one substance selected from silicides, nitrides and carbides of molybdenum and silicides, nitrides and carbides of tungsten as a main component, and a base mainly containing silicon nitride in which the heating element is embedded, wherein the base includes: a rare earth element component in an amount from 4 to 25% by mass in terms of an oxide thereof; a silicide of chromium in an amount from 1 to 8% by mass in terms of chromium silicide; and an aluminum component in an amount from 0.02 to 1.0% by mass in terms of aluminum nitride.

Growing community of inventors

Tsushima, Japan

Yoshihito Ikai