摘要:
Disclosed herein is a sound wave control device which is shaped in a lens form or a prism form from an acoustically rigid porous material, wherein numerous paths having different path lengths are provided and the apparent medium density is varied. This second wave control device is used to improve the sound quality and the directivity of the sound waves from a speaker and the directional control of noises.
摘要:
Disclosed herein is an engine noise control device for use in automobiles or the like comprising a noise control member which is attached to an opening of an engine room of an automobile or the like. The noise control member has a plurality of hollow conduit passages penetrating from one of surfaces to the other surface thereof. The hollow conduit passages are so arranged that the length of the conduit passages becomes shorter from the central portion to the peripheral portion of the noise control member. Thereby, a noise-propagating direction is changed by controlling the noise to reduce the energy of sounds radiated and/or diffracted to the outside.
摘要:
A carbon nanotube orientated composite formed by orientating carbon nanotubes in a given direction in a matrix having a heat conductivity lower than that of carbon nanotube, in which at least a part of carbon nanotubes are contacted with each other to be continuous from one end to the other end between both ends in the orientated direction, is provided as a material having a heat conductivity considerably higher than that of copper, aluminum or the like or a material to be disposed in rubber material having a low heat releasing characteristic to considerably improve the heat conduction, and also there are provided a method of producing the same as well as a pneumatic tire, a wheel for a vehicle, a tire-wheel assembly and a disc brake using this material.
摘要:
An elastic wheel includes a disk (1) having a base rim (2), a rim (3) for supporting a tire (10), and an annular elastic rubber body (4) arranged between the outer peripheral surface of the base rim (2) and the inner peripheral surface of the rim (3). A gap is formed between the elastic rubber body (4) and the outer peripheral surface of the base rim (2) or the inner peripheral surface of the rim (3). The elastic rubber body (4) with the gap has a spring constant that shifts from a smaller value to a larger value as the input load increases, so that it absorbs vibration under small input conditions while being prevented from undergoing substantial deformation under large input conditions. The elastic wheel ensures riding comfortablesess performance and provides improved vibrationproof performance and soundproof performance, regardless of whether the input load is small or large, without sacrificing durability and safety. In terms of soundproof performance, provision of the gap is particularly effective in suppressing high-frequency noise of 100 Hz or higher.
摘要:
A method for electrically attenuating a noise in an area for a sound wave to be propagatable in a three dimensional direction by making up a drive signal from the information on the noise and previously given filter coefficients by use of an adaptive digital filter and then generating an additional sound wave in accordance with the drive signal for cancellation of the noise. In the electric noise attenuation method, there are provided in a given region for noise attenuation, first and second error sensor groups for detecting an interference sound wave produced between the noise and additional sound wave, at a sampling time, a filter coefficient is calculated based on the information relating to the first error sensor group, at the next sampling time, another filter coefficient is calculated based on the information relating to the second error sensor group, and these operations are repeatedly executed sequentially for each error sensor to thereby update the filter coefficient of the adaptive digital filter.
摘要:
A noise reducing apparatus is disclosed, comprising a lens-type hollow body consisting of a plurality of inclined hollow tubular passages. The lens-type hollow body has a plane incident surface and a curved emission surface and the length L.sub.2 of the hollow tubular passage is optimized in accordance with relevant dimensional parameters of setting of the lens-type hollow body in a sound field, to reduce noise from a spot sound source efficiently.
摘要:
A noise control device which produces behind it an enlarged sound reducing region is disclosed. The device comprises a hollow structural body composed of a plurality of elongate hollow passages which are different in length and constructed such that the passage length is made the longest at a substantially center part in a vertical direction and is made gradually shorter from the center part toward upper and lower edges of the hollow structural body. The upper and lower edges allow direct propagation sound emitted from a noise source to pass thereover and therethrough.
摘要:
An elastic wheel having a disk 1 equipped with a base rim 2 and a rim 3 for supporting a tire includes a pair of guides 4 fixed annularly on the inner peripheral surface of the rim 3 and a pair of wall portions 5 fixed annularly on the both side areas in the axial direction of the wheel on the outer peripheral surface of the base rim 2, where rubber elastic bodies 6 are fitted annularly between the side surfaces of the guides 4 and the side surfaces of the wall portions, respectively. The elastic bodies 6 being installed are able to absorb vibrations by their shearing deformations, so that especially the riding comfortableness performance, the vibrationproof performance, and the soundproof performance can be improved against the small input load. Regarding the soundproof performance, furthermore, it is extremely effective on a high frequency area of 100 Hz or higher.
摘要:
A vibration free container for transportation comprises vibration isolating device which are arranged under the container and comprises a lower layer and an upper layer. The lower layer consists of at least two long laminated rubber bodies in the form of a parallelepiped extending in parallel with each other and upper layer consists of a plurality of column-shaped vibration isolators fixed between a bottom plate of the container and upper surfaces of the lamianted rubber bodies. Each of the laminated rubber bodies comprises rubber layers and metal plates alternately laminated. In another aspect the vibration free container comprises an outer casing and an inner casing received in the outer casing, and the vibration insulating device is interposed between the outer and inner casing to support the inner casing relative to the outer casing.
摘要:
A device for controlling a propagation direction of noise, which is preferably associated with a sound insulating wall to significantly improve its sound reducing effect of alleviating noise emitted from a noise source such as a railroad, highway and the like on which an electric car and automobiles run. The device comprises a hollow structural body composed of a plurality of elongated vertical hollow passages arranged at right angles to a substrate and spaced apart from each other by means of partition walls. The upper noise inlet side surface of the hollow passages face a propagation direction of noise emitted from the noise source and serve to refract and lag in phase the noise passed therethrough, thereby producing a sound reducing region located intermediate between a direct sound propagation and the refracted sound propagation. In one embodiment, a pair of hollow structural bodies are arranged in opposition to each other to form an arch type device. In another embodiment, the hollow structural body may be provided at its noise inlet or outlet side surface with an extension of the hollow passages.