Denso Corporation

Other

Nippon Soken, Inc.

Takumi Kataoka

Eturo Yasuda

Akira Fujii

Kaoru Kuzuoka

Masanori Yamada

Naohito Seko

Hitoshi Shindo

Itsuhei Ogata

Kentaro Yutani

Takashi Yamamoto

Toshiatsu Nagaya

Atsuhiro Sumiya

Hiroo Imamura

Yasuhiro Fukagawa

A valve device includes: a valve having a ball surface having a convex spherical shape, and a first opening opened in the ball surface to allow fluid to pass through; and a seat having an annular shape and opposing the ball surface to be in sliding contact, the seat being pressed against the ball surface, the seat having a second opening to communicate with the first opening. The seat has a sealing surface in a sliding contact with the ball surface at a valve closed time when the ball surface and the second opening overlap with each other, and a seat contact surface in a sliding contact with an opening inner wall surface or an opening end surface of the first opening at a valve opened time when the first opening and the second opening overlap with each other.

Valve device

A PZT dielectric ceramic material is sintered at a desired low temperature to prevent deterioration of the performance of the base material. An auxiliary oxide is used that is made by adding the oxide of at least one of tungsten and molybdenum to lead oxide in the following proportions:PbO+(WO+MoO)where x+y+z=1, 0.005&#x3c;y+z&#x3c;0.4 and y, z&#x2267;0. 0.5 mol % to 20 mol % of this auxiliary oxide is added to a mixture of a stock material of dielectric ceramic material or its calcination having a composition of ABOtype dielectric ceramic material where 0.9 molar ratio or more lead is included in site A assuming the proportion of site B is 1, and the material is mixed, formed and sintered. The content of tungsten and molybdenum combined is less than 0.098 mole in proportion to 1 mole of lead and the density of the dielectric ceramic material after sintering is 7.5 g/cmlarger. The auxiliary oxide is dispersed in the calcined powder to form a liquid phase at a desired temperature, to accelerate the sintering, thus making it possible to sinter at a lower temperature.

Dielectric ceramic material and method for producing the same

The thermistor element of the present invention is composed of a mixed sintered body aM M O bY O of a composition M M O (wherein M is Y, and M is at least one element selected from the elements such as Cr, Mn, Ti, etc.) as a perovskite compound and Y O , wherein molar fractions a and b satisfy the relations 0.05&lE;a<1.0, 0<b&lE;0.95 and a&plus;b&equals;1. Another wide-range type thermistor element of the present invention is composed of a perovskite compound M (M M )O , wherein M is at least one element selected from the elements of the groups II and IIIA excluding La in the Periodic Table, and each of M and M is at least one element selected from the elements of the groups IIB, IIIB, IVA, VA, VIA, VIIA and VIII. a and b satisfy the relations a&plus;b&equals;1 and 0<b<0.1, where a is a molar fraction of M and b is a molar fraction of M in M (M M )O .

Wide-range type thermistor element and method of producing the same

A ceramic piezoelectric transformer is provided which includes a compression mechanism. The compression mechanism is made up of, for example, a bolt and a nut which add a given compressive stress to a transformer body in a lengthwise direction thereof for absorbing a tensile stress arising from oscillations of the transformer body during operation, thereby allowing output energy from the transformer to be increased. In a modified form, a weight block is mounted on an end of the transformer body to increase the range of the output energy.

Piezoelectric transformer having increased voltage output

A lighting driver for a discharge lamp is provided. The discharge lamp is designed to be ignited in response to application of a voltage higher than a given set voltage and to maintain stable emission of light through supply of a given current. The lighting driver includes two voltage source circuits one of which applies a first voltage having a first frequency to a piezoelectric transformer for igniting the discharge lamp and the other applying a second voltage of a second frequency for keeping stable emission of light from the discharge lamp. The lighting driver also includes a frequency switch which switches between communication of the first voltage source circuit with the piezoelectric transformer and communication of the second voltage source circuit with the piezoelectric transformer depending on whether the discharge lamp has been ignited or not, thereby keeping the stable emission of light from the discharge lamp after ignited.

Lighting driver for discharge lamp

The thermistor element of the present invention is composed of a mixed sintered body aM,M,O,.bY,O,of a composition M,M,O,(wherein M,is Y, and M,is at least one element selected from the elements such as Cr, Mn, Ti, etc.) as a perovskite compound and Y,O,, wherein molar fractions a and b satisfy the relations 0.05&lE;a<1.0, 0<b&lE;0.95 and a&plus;b&equals;1. Another wide-range type thermistor element of the present invention is composed of a perovskite compound M,(M,M,)O,, wherein M,is at least one element selected from the elements of the groups II and IIIA excluding La in the Periodic Table, and each of M,and M,is at least one element selected from the elements of the groups IIB, IIIB, IVA, VA, VIA, VIIA and VIII. a and b satisfy the relations a&plus;b&equals;1 and 0<b<0.1, where a is a molar fraction of M,and b is a molar fraction of M,in M,(M,M,)O,.

PZT piezoelectric ceramics for forming a piezoelectric transformer includes a main composition consisting of Pb [Zr.sub.A Ti.sub.B (Zn.sub.1/3 Nb.sub.2/3).sub.c (Mn.sub.1/2 W.sub.1/2).sub.D ]O.sub.3. When A/B is in a range of 0.92-1.13, C is 0 or larger, D is in a range of 0.02-0.08 and total of A, B, C and D is 1, the piezoelectric transformer is fired at 1,100.degree. C. or lower, while having relatively high voltage rising ratio and efficiency. Therefore, a relatively low-priced Ag--Pd electrode having heat resistance of approximately 1,100.degree. C. can be used as an inside electrode of a laminated-type transformer. Thus, production cost of the piezoelectric transformer is reduced while the transformer has relatively high voltage rising ratio and efficiency.

Growing community of inventors

Nishio, Japan

Takumi Kataoka