Abstract: A moving core includes a magnetic body having a rough face-shaped wall portion at a side facing a stationary core, a plated layer portion provided on the magnetic body and including a micro concave and convex portion on the surface layer of the plated layer portion, and a lubricating layer portion provided so as to cover the plated layer portion to store lubricating particles in the concave portions of the plated layer portion. A clearance between adjacent convex portions of the micro concave and convex portion is smaller than a clearance between adjacent convex portions of concavity and convexity of the plated layer portion. The lubricating particle is larger than the clearance between the adjacent convex portions of the micro concave and convex portion and smaller than the clearance between adjacent convex portions of the plated layer portion.

Abstract: A torque increase resonator for facilitating delivery of intake air to a combustion chamber of an engine by resonating with intake air pulsation generated by the delivery of intake air to the combustion chamber includes a chamber wall. The chamber wall projects in a surge tank of an intake manifold to define a resonance chamber. The resonance chamber is prevented from communicating with intake air. The chamber wall includes a resonating member, which is a thin film and resonates with the intake air pulsation. The chamber wall is integrally formed.

Abstract: A sound quality control apparatus includes an air intake duct defining a suction passage, through which air is supplied to an engine, and having a double tube part, and an air cleaner that filters the air flowing through the suction passage. The double tube part includes an outer pipe and an inner pipe disposed in the outer pipe. The inner pipe defines a communicating passage communicating with the suction passage. The outer pipe and the inner pipe define a resonant chamber therebetween. The outer pipe has a branch opening part that opens in a vehicle interior of an automobile, or a branch opening part that opens toward a vicinity of the vehicle interior of the automobile. The inner pipe has a thin film partition wall that divides the resonant chamber airtightly from the communicating passage.

Abstract: According to a method for producing a duct, a cylindrical preform, which opens at its both end portions in a longitudinal direction and has a central part, is formed. The central part is narrowed with respect to the both end portions. The central part has a smaller cross-sectional area than that of the both end portion. The preform is formed from a thermoplastic material, which increases in strength when stretched. Next, the preform is heated. Then, stretch blow molding is performed on the preform by stretching the preform in axial and radial directions thereof, such that the cross-sectional area of the central part becomes generally the same as that of the both end portion, or equal to or larger than that of the both end portion. The central part is narrowed to such an extent that it retains predetermined strength after performing the molding on the preform.

Abstract: A silencer for attenuating a sound includes an inner duct in which gas flows, and an outer duct surrounding the inner duct with a gas layer formed between the outer duct and the inner duct. The sound is generated in one of an upstream side of the inner duct in a gas flow direction, a downstream side of the inner duct in the flow direction, and an inside of the inner duct. The inner duct includes a thin film over its entire surface. The film has a first reinforcement section formed in a direction parallel to the flow direction, and a plurality of vibrating surfaces. The film is bent at the first reinforcement section. Each combination of adjacent two of the plurality of vibrating surfaces is connected by the first reinforcement section. The first reinforcement section of the inner duct is fixed to the outer duct.

Abstract: An electromagnetic valve generally has a housing, a valve element, an electromagnetic driving portion and a filter. The housing forms a fluid flow passage therein. The valve element is installed in the housing to control a flow of a fluid through the fluid flow passage. The electromagnetic driving portion is installed in the housing to generate a magnetic attraction force when it is energized to actuate the valve element. At least a part of the electromagnetic coil is within the fluid flow passage. The filter is installed in the fluid flow passage on an upstream side of the at least a part of the electromagnetic driving portion to filtrate the fluid flowing through the fluid flow passage.

Abstract: An air-intake device having a noise reduction mechanism includes a surge tank connected to an intake manifold for introducing intake air into an internal combustion engine, an air duct connected to an upstream end of the surge tank and a resonator connected to the surge tank and the air duct. The resonator forms a resonator chamber connected to both the surge tank and the air duct. The surge tank is separated from the resonator chamber by a first vibrating member, and the air duct is separated from the resonator chamber by a second vibrating member. The noises in the surge tank are offset or reduced by resonating vibrations of the first vibrating member, and the noises in the air duct are offset or reduced by resonating vibrations of the second vibrating member. Thus, the intake air noises are effectively reduced by a simple combination of the resonator and the vibrating members.

Abstract: A noise reduction apparatus includes an intake passage forming member defining an intake passage, a resonator, and a vibration film. Intake air drawn into a combustion chamber of an internal combustion engine flows through the intake passage. The resonator has an inner volume part branching from the intake passage. The vibration film is placed to separate the intake passage from the inner volume part. The vibration film is vibrated by a sound pressure of a sound that is generated in the combustion chamber and that propagates through the intake passage. The vibration film has a projection part, which separates the vibration film into an inner vibration film part and an outer vibration film part.

Abstract: A moving core includes a magnetic body having a rough face-shaped wall portion at a side facing a stationary core, a plated layer portion provided on the magnetic body and including a micro concave and convex portion on the surface layer of the plated layer portion, and a lubricating layer portion provided so as to cover the plated layer portion to store lubricating particles in the concave portions of the plated layer portion. A clearance between adjacent convex portions of the micro concave and convex portion is smaller than a clearance between adjacent convex portions of concavity and convexity of the plated layer portion. The lubricating particle is larger than the clearance between the adjacent convex portions of the micro concave and convex portion and smaller than the clearance between adjacent convex portions of the plated layer portion.

Abstract: An electromagnetic valve generally has a housing, a valve element, an electromagnetic driving portion and a filter. The housing forms a fluid flow passage therein. The valve element is installed in the housing to control a flow of a fluid through the fluid flow passage. The electromagnetic driving portion is installed in the housing to generate a magnetic attraction force when it is energized to actuate the valve element. At least a part of the electromagnetic coil is within the fluid flow passage. The filter is installed in the fluid flow passage on an upstream side of the at least a part of the electromagnetic driving portion to filtrate the fluid flowing through the fluid flow passage.