Abstract: An improved piezoelectric sensor for detecting pressure, vibration, acceleration or the like physical quantity is disclosed. The pressure sensor to be attached to a cylinder block of an internal combustion engine includes a main body adapted to be attached to the cylinder and defining an axially extending hole therewithin, a diaphragm attached to one end of the main body for closing the hole; and a piezoelectric element disposed within the hole so that the pressure within the cylinder is transmitted to the piezoelectric element through the diaphragm. The piezoelectric element is a circular or polygonal disc with a thickness of 0.3-1.5 mm and is formed of a single crystal piezoelectric ceramic having a Curie temperature greater than 500.degree. C., such as LiNbO.sub.3.

Abstract: An oxygen sensor element comprises a reference-gas-side electrode on one surface of a solid electrolyte having oxygen-ion conductivity, a detection-gas-side electrode on another surface, and a porous coated layer formed of a heat-resistant metal oxide formed on the surface of the detection-gas-side electrode, wherein at least a part of said coated layer is formed of a nonstoichiometric compound of transition metal (Ti, Co, Ni) oxide, and a portion formed of said nonstoichiometric compound carries a catalyst for equilibrating gas components of a detection gas. The catalyst (Pt, Rh) is 0.2-5 mole % relative to the portion formed of said nonstoichiometric compound. The coated layer may be thickened at the distal end portion.

Abstract: A jacket having a pair of small helical gears is spline-fitted around a splined shaft. Since the small helical gears have an adverse helix angle to each other, the jacket moves along the spline shaft in the axial direction so as to distribute an equal torque to both small helical gears. The splited torque is transmitted to a pair of drive shafts each of which drives the main rotor of a helicopter through a combination of gear and pinion. The drive shafts are fixed axially and therefore helical gears or double-helical gears can be used in the combination of gear and pinion.

Abstract: A refrigerator with heat exchanger optimally configured to conserve electricity and improve a food storing capability at its best state. The refrigerator includes: a freezing room connected from an evaporator through a circulating passage, the freezing room having the circulating passage which circulates an air cooled by the evaporator; a storage room connected to the freezing room, in which a temperature of the storage room is set higher than that of the freezing room; a flow-in passage connected to the storage room where the air cooled by the evaporator flows into the storage room; a flow-out passage connected from the storage room where a chilled air flows out of the storage room; and a heat exchanger for exchanging heat between the cooled air flowing through the circulating passage and the chilled air flowing through the flow-out passage, so that the temperature inside the storage room is evenly and smoothly stable.

Abstract: In an oxygen sensor of the type having an oxygen ion conductive tube of solid electrolyte, a ceramic heater disposed within the oxygen ion conductive tube for heating the same is in the form of a quadrangular prism or a bar of a rectangular cross section. The ceramic heater is formed by piling up ceramic green sheets with metallic thick-film patterns for heat generating resistors interposed between adjacent two of the ceramic green sheets. The ceramic heater is so shaped as to satisfy the relation of b/a=0.75.about.1 where "a" is the width and "b" is the thickness of the ceramic heater. The metallic thick films, which the metallic thick-film patterns are turned to by firing, are arranged so as to be parallel to the side surfaces opposed in the thickness direction of the ceramic heater.

Abstract: Oxygen-sensor element comprises reference-gas-side and detection-gas-side electrodes on both surfaces of a solid-electrolyte body, and a porous protective layer on the surface of the detection-gas-side electrode, wherein at least a part (including at least a surface layer) of said porous protective layer is formed by a granular texture of a grain size of 0.1 to 0.5 .mu.m formed mainly of a nonstoichiometric compound of a transition metal oxide (TiO.sub.x), and a catalyst for having gas components of the gas to be measured react is carried in at least a part (including at least a surface layer) of the porous protective layer. Oxidation reaction of gas components is improved to prevent deterioration of the responsive property.

Abstract: A physical quantity sensor e.g., temperature sensor having a resistor pattern and a ceramic support carrying the resistor pattern. The resistor pattern has an ionizing component retention conductor pattern which is branched at its negative terminal side.The resistor pattern with branched pattern are stacked between the ceramic support layers.Migration in the resistor pattern is suppressed to prevent the resistance of the resistor pattern from being increased for assuring accurate measurement of temperature. The sensor is operated without cooling to 0.degree. C.

Abstract: Oxygen sensor for air-fuel ratio control is provided with a sensor element having an oxygen ion-conductive main body and electrodes on both sides thereof, and at least one porous protective layer covering the electrode on the exhaust gas side. The protective layer includes an oxygen storage component OSC without copresence of a noble metal catalyst. The protective layer is intermeshingly connected to the main body via spherical protrusions of the main body. Double-layered protective layer structure includes OSC noncontaining layer (optionally containing catalyst) and OSC containing layer, as inner and outer protective layer or vice versa. OSC containing layer is formed by impregnation with OSC-solution through immersing the respective porous protective layer, or by cosintering the OSC containing green coating layer. By impregnation 0.2-8 wt %, or by cosintering 0.2-30 wt %, of OSC metal element is containable. The outer protective layer is thinner and more porous than the inner protective layer.

Abstract: A device for detecting a change in internal pressure of a cylinder includes a cylinder head, an ignition plug threadingly fitted into a plug insertion hole of the cylinder head. An annular piezoelectric sensor is secured in the plug insertion hole by screwing the plug into the insertion hole. The sensor has such an outer periphery that, when the ignition plug is screwed into the plug hole, a part of the outer periphery of the sensor placed is brought into engagement with an inside periphery of the plug hole and is thereby prevented from being further rotated in the screwing direction. By using a gasket having the same relative shape to the periphery of the plug insertion hole as that of the above sensor, rotation of the sensor can be prevented even when the sensor does not have such a relative shape.

Abstract: Poisoning-preventive and poisoning-resistant materials including: a poisoning-preventive layer-possessing support comprising a support and, formed thereon, a poisoning-preventive layer having a compound containing at least one element selected from the Group IIa element of the periodic table; a poisoning-resistant catalyst for catalytic converter, which comprises a support, a noble metal catalytic component deposited on the support, and a poisoning-preventive layer formed on the side of the catalytic component exposed to an exhaust gas, the poisoning-preventive layer having a compound containing at least one element selected from the Group IIa elements of the periodic table; an exhaust gas converter device comprising a poisoning-preventive material provided on the exhaust gas inlet side, the poisoning-preventive material being either a ceramic material or the poisoning-preventive layer-possessing support as described above, the ceramic material comprising a compound containing at least one element selected fr

Abstract: A retaining ring is provided for temporarily holding a pressure sensor in place within a spark plug attaching hole prior to installation of a spark plug. The retaining ring is resiliently deformed into a stressed positioned to attach itself to a circumferential wall of the spark plug attaching hole. In one embodiment, a gasket is adapted to serve also as such a retaining ring.

Abstract: A pressure sensor having a ceramic support, a first ceramic layer attached to a peripheral portion of one side of the ceramic support, and a second ceramic layer which is attached to a peripheral portion of another side of the ceramic support such that the pressure sensor is shaped as an integral assembly. The ratio of the thickness of the first ceramic layer to that of the second ceramic layer is in the range of 1:10 to 1:1. The ratio of the thicknesses of the first and second ceramic layers to thickness of the ceramic support is no more than 1:2. The pressure sensor further includes a hollow space formed between the ceramic support and at least one of the first and second ceramic layers so that, after shaping as an integral assembly, the ceramic layer or layers will work as a diaphragm that is capable of deformation under pressure.

Abstract: A pressure sensor including at least two ceramic layers formed as elongated sheets and bonded together with a gap therebetween at one end so as to form a diaphragm of a portion of one of the ceramic layers that faces the gap and that receives on an outer surface thereof the pressure to be measured, a pressure-sensitive electrode portion from which an electric output corresponding with the pressure to be measured is generated on the basis of the amount of strain of the diaphragm that develops under the pressure to be measured, the pressure-sensitive electrode portion being provided on or around the diaphragm, and a plurality of conductor paths that are connected to the pressure-sensitive electrode portion and that extend along the length of the ceramic layers, the conductor paths having terminals at the other end of the bonded ceramic layers for connection to an external electric circuit.

Abstract: A pressure sensor having a ceramic substrate formed from a first unsintered ceramic material, and a diaphragm capable of deformation under pressure, and formed of a second unsintered ceramic material having a factor of shrinkage upon sintering smaller than that of the first material. The diaphragm is fixed to the periphery of a surface of the ceramic substrate to form an integral assembly having a hollow space formed therebetween upon sintering due to the difference in the factor of shrinkage of the first and second materials.

Abstract: A tool is provided for loosening or tightening a spark plug while interposing a gasket and a pressure sensor between the spark plug and a cylinder head. The tool consists of concentric, relatively rotatable inner and outer cylinders. The inner cylinder is engageable with the spark plug for rotation together therewith and for loosening or tightening the same. The outer cylinder is lockingly engageable with a cylinder head by means of an axial projection of the outer cylinder and a groove of the cylinder head. The outer cylinder is further lockingly engageable with the gasket by means of a locking leg of the outer cylinder and a peripheral cut of the gasket. The gasket is thus lockingly engageable with the cylinder head by way of the outer cylinder for preventing the pressure sensor from rotating relative to the cylinder head when the spark plug is loosened or tightened.

Abstract: Oxygen sensor for air-fuel ratio control is provided with a sensor element having an oxygen ion-conductive main body and electrodes on both sides thereof, and at least one porous protective layer covering the electrode on the exhaust gas side. The protective layer includes an oxygen storage component OSC without copresence of a noble metal catalyst. The protective layer is intermeshingly connected to the main body via spherical protrusions of the main body. Double-layered protective layer structure includes OSC noncontaining layer (optionally containing catalyst) and OSC containing layer, as inner and outer protective layer or vice versa. OSC containing layer is formed by impregnation with OSC-solution through immersing the respective porous protective layer, or by cosintering the OSC containing green coating layer. By impregnation 0.2 -8 wt %, or by cosintering 0.2-30 wt %, of OSC metal element is containable. The outer protective layer is thinner and more porous than the inner protective layer.

Abstract: A cylinder with a connected sleeve for supply and displacement of fluid through connection to an external piping, as well as an apparatus for and a method of manufacturing same are disclosed. An opening is formed to extend through the wall of a tubular body of the cylinder to provide a communication between the interior and the exterior thereof. A substantially flat abutment is formed on the outer surface around the opening. The outer peripheral surface of a connected sleeve is annularly in contact with the inner peripheral edge of the flat abutment, and the tubular body and the connected sleeve are joined together as by a welding operation.

Abstract: A zirconia-base solid electrolyte function element comprising a zirconia-base solid electrolyte substrate, wherein a reinforcing layer is formed directly on each side of said zirconia-base solid electrolyte substrate, the ratio of the shrinkage modulus to the zirconia-base electrolyte substrate to the reinforcing layers is 1.01 to 1.08, and the substrate and the reinforcing layers have been sintered simultaneously.

Abstract: A valve sleeve is fitted around valve rotor to define a rotary valve. The valve sleeve is characterized by the configuration of axially extending grooves which are formed in its internal surface. Specifically, the axial groove has a bottom surface which includes a lengthwise portion having a constant depth. The bottom surface of the groove is connected to the wall surfaces which are located at the opposite lengthwise ends as well as with the opposite lateral side walls by arcuate surfaces. At least one of the wall surfaces which are located at the lengthwise ends has an angle of inclination which exceeds 60.degree..

Abstract: An air/fuel ratio sensor with a solid electrolyte oxygen pump and oxygen sensor defining a closed space therebetween. At least in the oxygen pump, porous electrodes sandwich an ionic oxygen conductive solid electrolyte. The voltage impressed on the electrodes of the pump is limited to a predetermined level, e.g., 6 V, in order to prevent blackening and cracking.