Abstract: The valve seat includes an iron-based sintered alloy subjected to oxidation treatment, which is obtained by subjecting an iron-based sintered alloy including: 4 mass % to 15 mass % of Co particles; and hard particles each containing at least one compound of an intermetallic compound, a carbide, a silicide, a nitride, or a boride that has one or more kinds of elements selected from group 4a to 6a elements in a periodic table, and having a hardness of from 600 HV to 1,600 HV to oxidation treatment, and which has an oxide mainly including triiron tetraoxide (Fe3O4) and cobalt oxide (CoO) formed on a surface and in an interior of the iron-based sintered alloy. The iron-based sintered alloy subjected to oxidation treatment has an area ratio of the oxide of from 5% to 25% in a cross section thereof in a state prior to installation on the cylinder head.

Abstract: Provided is a valve seat having excellent strength and wear resistance. In a valve seat using an iron-based sintered alloy, an oxide mains composed of triiron tetroxide is formed by oxidation treatment on the surface and interior of the iron-based sintered alloy, and the average area ratio of the oxide mainly composed of triiron tetroxide in a cross section of the iron-based, sintered alloy in the state prior to installation on a cylinder head is 5 to 20%. Preferably, the iron-based sintered alloy contains hard particles formed from at least one compound of carbides, silicides, nitrides, borides, and intermetallic compounds containing one or more elements selected from groups 4a to 6a of the periodic table, and the average area ratio of the hard particles in the cross section of the iron-based sintered alloy in the state prior to installation on a cylinder head is 5 to 45%.

Abstract: The valve seat includes an iron-based sintered alloy subjected to oxidation treatment, which is obtained by subjecting an iron-based sintered alloy including: 4 mass % to 15 mass % of Co particles; and hard particles each containing at least one compound of an intermetallic compound, a carbide, a silicide, a nitride, or a boride that has one or more kinds of elements selected from group 4a to 6a elements in a periodic table, and having a hardness of from 600 HV to 1,600 HV to oxidation treatment, and which has an oxide mainly including triiron tetraoxide (Fe3O4) and cobalt oxide (CoO) formed on a surface and in an interior of the iron-based sintered alloy. The iron-based sintered alloy subjected to oxidation treatment has an area ratio of the oxide of from 5% to 25% in a cross section thereof in a state prior to installation on the cylinder head.

Abstract: The valve seat includes an iron-based sintered alloy subjected to oxidation treatment, which is obtained by subjecting an iron-based sintered alloy including: 4 mass % to 15 mass % of Co particles; and hard particles each containing at least one compound of an intermetallic compound, a carbide, a silicide, a nitride, or a boride that has one or more kinds of elements selected from group 4a to 6a elements in a periodic table, and having a hardness of from 600 HV to 1,600 HV to oxidation treatment, and which has an oxide mainly including triiron tetraoxide (Fe3O4) and cobalt oxide (CoO) formed on a surface and in an interior of the iron-based sintered alloy. The iron-based sintered alloy subjected to oxidation treatment has an area ratio of the oxide of from 5% to 25% in a cross section thereof in a state prior to installation on the cylinder head.

Abstract: The valve seat includes an iron-based sintered alloy subjected to oxidation treatment, which is obtained by subjecting an iron-based sintered alloy including: 4 mass % to 15 mass % of Co particles; and hard particles each containing at least one compound of an intermetallic compound, a carbide, a silicide, a nitride, or a boride that has one or more kinds of elements selected from group 4a to 6a elements in a periodic table, and having a hardness of from 600 HV to 1,600 HV to oxidation treatment, and which has an oxide mainly including triiron tetraoxide (Fe3O4) and cobalt oxide (CoO) formed on a surface and in an interior of the iron-based sintered alloy. The iron-based sintered alloy subjected to oxidation treatment has an area ratio of the oxide of from 5% to 25% in a cross section thereof in a state prior to installation on the cylinder head.

Abstract: Provided is a valve seat having excellent strength and wear resistance. In a valve seat using an iron-based sintered alloy, an oxide mains composed of triiron tetroxide is formed by oxidation treatment on the surface and interior of the iron-based sintered alloy, and the average area ratio of the oxide mainly composed of triiron tetroxide in a cross section of the iron-based, sintered alloy in the state prior to installation on a cylinder head is 5 to 20%. Preferably, the iron-based sintered alloy contains hard particles formed from at least one compound of carbides, silicides, nitrides, borides, and intermetallic compounds containing one or more elements selected from groups 4a to 6a of the periodic table, and the average area ratio of the hard particles in the cross section of the iron-based sintered alloy in the state prior to installation on a cylinder head is 5 to 45%.

Abstract: A sintered alloy for valve seats is comprised of carbon at 1 to 2 percent by weight, chromium at 3.5 to 4.7 percent by weight, molybdenum at 4.5 to 6.5 percent by weight, tungsten at 5.2 to 7.0 percent by weight, vanadium at 1.5 to 3.2 percent by weight, and the remainder of iron and unavoidable impurities. Enstatite particles at 1 to 3 percent by weight, hard alloy particles (A) with a Vickers hardness of 500 to 900 at 15 to 25 percent by weight, and hard alloy particles (B) with a Vickers hardness of 1000 or more at 5 to 15 percent by weight (A+B=35 percent by weight or less) are dispersed in the matrix of the sintered alloy skeleton distributed with carbide. Copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of the skeleton.

Abstract: A sintered alloy for valve seats is comprised of carbon at 1 to 2 percent by weight, chromium at 3.5 to 4.7 percent by weight, molybdenum at 4.5 to 6.5 percent by weight, tungsten at 5.2 to 7.0 percent by weight, vanadium at 1.5 to 3.2 percent by weight, and the remainder of iron and unavoidable impurities. Enstatite particles at 1 to 3 percent by weight, hard alloy particles (A) with a Vickers hardness of 500 to 900 at 15 to 25 percent by weight, and hard alloy particles (B) with a Vickers hardness of 1000 or more at 5 to 15 percent by weight (A+B=35 percent by weight or less) are dispersed in the matrix of the sintered alloy skeleton distributed with carbide. Copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of the skeleton.

Abstract: To provide an electronic timepiece enabling reliable detection of a state of rotation of an indication wheel such as a date dial. An ultrasonic motor 1130 has an ultrasonic rotor pinion 1134b. A date dial 1120 is disposed on a main plate 1102 in such a way as to rotate relative thereto. The ultrasonic rotor pinion 1134b is meshed with an intermediate date driving gear wheel 1142a. A date driving wheel 1150 is rotatably disposed on the main plate 1102. A date driving gear wheel 1150b is meshed with an intermediate date driving pinion 1142b. A date driving gear portion 1150b is meshed with a dial gear portion 1120a. A contact point spring 1160 is disposed on a spring guiding portion 1150d. The contact point spring 1160 rotates integrally with the date driving wheel 1150 through the rotation of the date driving wheel 1150. The state of rotation of the date driving wheel 1150 can be detected by contact of the contact point spring 1160 with the contact point pattern 1174.

Abstract: An electronic timepiece has a wheel train mounted for undergoing rotation and a transmission wheel for undergoing rotation in accordance with rotation of the wheel train. A contact point spring is connected to the transmission wheel for rotation therewith. The contact point spring extends substantially linearly through a rotational center of the transmission wheel. First and second detection patterns contact the contact point spring during rotation of the transmission wheel to generate a rotational position detecting signal corresponding to a rotational position of the transmission wheel. The first and second detection patterns are disposed at an angle of substantially 180 degree relative to the rotational center of the transmission wheel.

Abstract: A calendar electronic timepiece comprises a signal generating circuit for generating a date signal, a driving circuit for outputting a driving signal in accordance with the date signal generated by the signal generating circuit, and an ultrasonic motor driven by the driving signal outputted by the driving circuit. The ultrasonic motor is comprised of a piezoelectric vibrator having an electrode pattern and being driven by the driving signal outputted from the driving circuit to undergo expansion and contraction movement, a vibrating member connected to the piezoelectric vibrator and vibrationally driven by expansion and contraction movement of the piezoelectric vibrator, and a date dial disposed on the vibrating member to be frictionally driven by expansion and contraction movement of the piezoelectric vibrator.

Abstract: To provide an electronic timepiece enabling reliable detection of a state of rotation of an indication wheel such as a date dial.An ultrasonic motor 1130 has an ultrasonic rotor pinion 1134b. A date dial 1120 is disposed on a main plate 1102 in such a way as to rotate relative thereto. The ultrasonic rotor pinion 1134b is meshed with an intermediate date driving gear wheel 1142a. A date driving wheel 1150 is rotatably disposed on the main plate 1102. A date driving gear wheel 1150b is meshed with an intermediate date driving pinion 1142b. A date driving gear portion 1150b is meshed with a dial gear portion 1120a. A contact point spring 1160 is disposed on a spring guiding portion 1150d. The contact point spring 1160 rotates integrally with the date driving wheel 1150 through the rotation of the date driving wheel 1150. The state of rotation of the date driving wheel 1150 can be detected by contact of the contact point spring 1160 with the contact point pattern 1174.

Abstract: This invention provides a method for the prevention of oxidation of resulting methacrolein immediately after its discharge from a reaction tube upon production of the methacrolein by vapor-phase oxidation of isobutylene, tertiary butanol or methallyl alcohol with a molecular-oxygen-containing gas in the presence of a catalyst. An inert gas and/or recirculated reaction gas or a mixed gas of an inert gas and/or recirculated reaction gas and air is fed and mixed with a reaction product gas immediately after an outlet of the reaction tube.

Abstract: Disclosed herein is a process for bringing methacrylic acid, which has been obtained by the catalytic oxidation of compound having 4 carbon atoms, into contact with a basic anion-exchange resin so as to remove byproduced dibasic acids and the like from the methacrylic acid and to purify the same.

Abstract: A water jet discharge pipe which produces a wide effective spray area and long water reach at low pressure and water volume. Compressed air is injected around the periphery of the pressurized water stream produced through an inner cylindrical member and which is throttled by a nozzle extending into such inner cylindrical member. The injected air prevents reduction of the flow velocity of the water by contact with the inner wall of the cylindrical member. In addition, external air is introduced through air inlets in an outer cylindrical member extending from the inner cylindrical member so as to straighten the air layer accompanying the water jet exiting from the inner cylindrical member and suppress premature dispersal of the water stream prior to ejection from the outer cylindrical member. After such ejection, expansion of the injected air atomizes the water stream to provide large area coverage thereof.

Abstract: A sheet-wound transformer comprises a magnetic core, a number of coil windings formed of sheet conductors wound around the magnetic core, and a plurality of cooling panels inserted in the coil windings. A number of ribs are provided in each cooling panel so as to extend in parallel with each other for guiding the flow of a coolant therethrough. Leading and trailing ends of the ribs are located respectively on two lines, the inclination of each line being varied between the central portion and end portions thereof, so that the displacement between two ends of adjacent pair of ribs located on an end portion of the line is made larger than the displacement between two ends of ribs located on the central portion of the line.

Abstract: A spraying device for a fire hose is provided with a bulb having a large inlet in one side and a plurality of small outlets in another side, the inlet being connected to the top end of a fire hose by way of a broad pipe, the outlets being connected to a plurality of annular nozzles by way of narrow pipes respectively in a manner that each narrow pipe is in the normal relation to the bulb wall, so as to convert the velocity head of water into pressure head through the bulb and deliver water through the nozzles a long distance in spray form.