42results about How to "Reduce sound radiation" patented technology

Vibro-acoustic attenuation or reduced energy transmission. The present invention relates to devices that display frequency zones of strong vibro-acoustic attenuation or reduced energy transmission. This can be used in particular, although not necessarily solely, in applications that require lightweight materials with good mechanical properties and good vibro-acoustic response or in applications that require materials with high sound reflection, absorption or sound isolation in a certain frequency band.

A muffler system for a compressor includes an expansion chamber muffler for reducing pressure pulses at the compressor's fundamental pulsation frequency and a side-branch muffler for filtering high-frequency pressure pulses. The expansion muffler is positioned along the compressor discharge stream at a location that maximizes pulsation reduction at the compressor's fundamental pulsation frequency. The side-branch muffler is tuned to the frequency at which the pulsation reduction for the expansion muffler is at a minimum.

The invention discloses a vehicle brake system simulation testing stand. The testing stand includes a testing stand, a column and a fixing stand, wherein one end of a top portion of the testing standis equipped with the fixing stand through a bolt, one side of the fixing stand is equipped with a vehicle bridge portion through a mounting support, one side of the vehicle bridge portion is connectedwith a brake disc through a rotation shaft, one side of the brake disc is welded with a connection shaft, one end of the connection shaft is connected with the rotation shaft through a coupling, a top portion of the vehicle bridge portion is equipped with a casing through a bolt, the casing is internally provided with a doughnut shape-like oil cavity, two sides at a bottom end in the doughnut shape-like oil cavity are provided with a piston through a mounting member, two sides of a top end of the brake disc are provided with friction blocks, and the other end of a top portion of the testing stand is equipped with a supporting plate through a bolt. The testing stand is advantaged in that functions are various, operation is simple, production is convenient, multiple test demands are satisfied, and the testing stand is suitable for wide popularization and application.

The invention relates to the field of rail damping and denoising, in particular to a damping jacket for a railway rail and an assembly method thereof. The damping jacket for the railway rail comprises an expansion layer clung to the rail base and rail web of the railway rail, wherein a coating is formed outside the expansion layer, sealing layers are formed at two ends of the expansion layer and the coating, a closed space is formed by the expansion layer, the coating and the sealing layers, and the closed space is filled with liquid damping material. The assembly method comprises the steps as follows: (1) connecting the expansion layer, the coating and the sealing layer at one side together; (2) injecting the liquid damping material to a cavity; (3) arranging the other sealing layer at the opening position; (4) sleeving the damping jacket from one end of the railway rail; and (5) arranging sleepers at the bottom of the railway rail. According to the invention, the damping jacket filled with the damping material is coated on the rail, and the damping material has the damping and the denoising functions, so that the wheel rail noise generated by the rail vibration is effectively reduced.

The invention discloses a low-shrinkage HIPS composite material for solving abnormal sound, and a preparation method thereof. The material comprises, by weight, 60-80 parts of HIPS resin, 3-10 parts of a rubber composite material, 8-20 parts of a reinforcing agent, 3-10 parts of a blocking agent, 0.3-1.5 parts of a weather-proof agent, 0.1-0.6 part of an antioxidant and 0.1-0.6 part of a lubricant. The material not only has excellent strength, toughness and dimensional stability, but also can play a role in vibration and noise reduction, can solve the common abnormal sound problem of current household appliances and improve the living environment of people, and is low in comprehensive cost and wide in application range.

A shape for sheet metal stampings is provided that will minimize the radiation of sound from the panel, to thereby reduce or eliminate the need to add supplemental acoustical absorbing or barrier materials. The sheet metal panel shape includes a crown portion, a peripheral flange that extends around the boundary of the crown portion, a flat portion that truncates the crown, and a bead pattern that is formed in at least the flat portion of the panel, whereby the crown and the flat and the bead pattern cooperate to define a panel shape that has low sound radiation. The bead pattern can also extend part way or more into the crown portion.

The invention discloses an active control device for propeller shaft transverse vibration. The active control deice comprises a stern bearing, a middle bearing and a thrust bearing which are sequentially distributed in an axial direction of a propeller shaft, and further comprises an electromagnetic bearing assembly, wherein one end, close to the stern bearing, of the propeller shaft is connectedto counterweight, and the other end of the propeller shaft is connected to a motor; the electromagnetic bearing assembly comprises an electromagnetic bearing, a displacement sensor, a controller and apower amplifier, wherein the electromagnetic bearing is arranged on the propeller shaft; the displacement sensor is mounted on the electromagnetic bearing; the displacement sensor is connected to thecontroller; and the power amplifier is separately connected to the controller and the electromagnetic bearing. The active control device can reduce load of the stern bearing or the middle bearing, sothat bearing friction force is reduced or eliminated.

The invention provides a light wood structure sound-proof wall system and a manufacturing method thereof, and belongs to the technical field of building engineering. Through the structural design of discontinuous floor board and a double-deck sound-proof wall, under a premise of meeting the safety, and the purpose of reducing lateral sound transmission caused by the floor board and a top layer ceiling in the structurally horizontal direction is realized. Meanwhile, the joint connection of a wall body frame structure and a floor board frame structure is designed, and structural sound transmission between a partition frame and the floor board frame is reduced. The floor board structure is designed to reduce the influence of floor board impact sound on adjacent rooms in the perpendicular andhorizontal directions.

Systems and devices of the various embodiments may provide a low-drag, variable-depth acoustic liner having shared inlet volumes. Various embodiments may include a low-drag, variable-depth acoustic liner providing aircraft noise reduction. Acoustic liners according to the various embodiments may be used in engine nacelles and / or on external surfaces of an aircraft to reduce acoustic radiation. Acoustic liners according to various embodiments may provide increased broadband acoustic performance with less drag than conventional liners. Various embodiments may provide an acoustic liner with a reduced open area of the facesheet, and therefore reduced drag of the liner, when compared with conventional acoustic liners.

A device for active noise reduction has a chamber, which is arranged laterally in relation to a gas flow, and a chamber opening constructed in one wall of the chamber. In the area of the chamber opening, a deflection device is adjustably arranged. The deflection device, in a first position, at least partially directs the gas flow running by the chamber opening into the chamber, in order to compress air there, and, in a second position, directs the gas from the chamber to the gas flow, in order to release the gas inside the chamber. The resulting alternating pressure inside the chamber is radiated through the chamber opening as sound and overlays the disturbing sound.

The invention discloses a ship noise reduction device. The ship noise reduction device is characterized by comprising a carrying board 1, a hollow damping mass block 2, a sound absorption material 3 and a band board 4. The hollow damping mass block 2 is installed on the carrying board 1. The middle portion of the carrying board is broken and the hollow damping mass block is fixed to the position between the two parts of the carrying board. The band board 4 is fixed to the hollow damping mass block 2. The sound absorption material 3 is installed on the band board 4. By the adoption of the ship noise reduction device, vibration and sound radiation in an engine compartment section of a ship are effectively reduced, the benefit ratio is high, economic cost is saved, the quality is guaranteed, and the production yield is increased.

The invention supplied a method that can decline echo without reducing vibration of the board or diaphragm, but instead with the superficial of the board or diaphragm being densely covered with chase and gaping place.

A bearing bush is for a holder, which is for fastening a component, particularly of a fuel distributor, to an add-on structure. The bearing bush has an inner bush part, which is made of a metallic material, and an outer bush part, which is made of a metallic material, and an elastically deformable damping element. The outer bush part has a continuous recess, in which the inner bush part is situated. The damping element is situated between the inner bush part and the outer bush part. A holder having such a bearing bush is also specified. In addition, a fuel-injection system having a fuel distributor and at least one holder is specified, which is used for fastening the fuel distributor on an internal combustion engine.

The invention relates to a fuel injection system (10) having a high-pressure fuel pump (18) which has an intake valve (28), wherein a non-return valve (42) is arranged upstream of the intake valve (28) in the direction of flow of a fuel (12) in the fuel injection system (10), which blocks the return flow of a fuel volume, which has not been conveyed by the high-pressure fuel pump (18) into a high-pressure region (36), into a low-pressure system (32) of the fuel injection system (10).

The invention discloses a bottom plate for an engineering machine cab. The bottom plate comprises an upper-layer flat plate, a lower-layer prestress reinforcement plate and a locating plate, the upper-layer flat plate, the lower-layer prestress reinforcement plate and the locating plate are all made of steel plates, the upper-layer flat plate is welded to the top face of the lower-layer prestress reinforcement plate, and the locating plate is welded to the bottom face of the lower-layer prestress reinforcement plate. Through the stamping technology, reinforcement ribs are formed on the surface of the lower-layer prestress reinforcement plate, and structural prestress is formed in the lower-layer prestress reinforcement plate. According to the bottom plate, the problems that vibration and sound radiation of the flat bottom plate of a current traditional engineering machine cab are obvious, and the bending and torsion resisting capacity is insufficient can be solved.

The invention discloses a train noise-reducing wheel, which comprises a web (1), a rim (2) and a hub (3). An annular noise shielding plate (4) is fixed, the outer edge of the noise shielding plate (4) is in contact with the rim (2) of the wheel, and the inner edge is in contact with the hub (3) of the wheel. The wheel can suppress noise generation, hinder noise transmission, has good noise reduction effect, is easy to install, does not change the shape of the main body of the wheel, and is easy to popularize and implement.

The invention proposes a closed cavity type PVDF thin-film loudspeaker. The closed cavity type PVDF thin-film loudspeaker comprises a main structure and an impedance converter; the main structure comprises a PVD thin film, a sound absorbing material layer and a glass fiber reinforced plastics back cavity; the PVDF thin film has double-sided electrodes; the double-sided electrodes respectively leadout external electrodes; the PVDF thin film and the double-sided electrodes are subjected to insulation encapsulation, and parts of the external electrodes are exposed during the insulation encapsulation; an open surface of the glass fiber reinforced plastics back cavity is a cambered surface with a rectangular projection, and the PVDF thin film after being subjected to the insulation encapsulation is sealed and fixedly connected with the edge of the open surface of the glass fiber reinforced plastics back cavity through a sealant; the sound absorbing material layer is fixed inside the glassfiber reinforced plastics back cavity body, and the sound absorbing material layer is not in contact with the PVDF thin film; and the main structure is connected with an external standard power amplifier through the impedance converter. The closed cavity type PVDF thin-film loudspeaker provided by the invention can effectively improve the sound radiation efficiency of the PVDF thin-film loudspeaker and reduce the sound radiation behind the PVDF thin-film loudspeaker, so as to solve the problems of the driving difficulty of the PVDF thin-film loudspeaker, the poor low frequency effect and the noise pollution behind the loudspeaker.

The invention relates to a multi-stage piston compressor which comprises a compressor unit (1) having a plurality of air-cooled cylinders (10a-10c), the crankshaft (8) of said compressor unit being housed in a crankcase (6) and driving a motor unit (3) that is flange-mounted on an end face (2) on said compressor. On the opposing end face (4) of the compressor unit (1), a cooler unit (5) is arranged, mounted on said compressor unit and driven by the crankshaft (8), the integrated axial fan wheel (9) of said cooler unit blowing the generated cooling air substantially outwards along the compressor unit (1) and, in order to conduct cooling air externally in the region of said compressor unit (1), at least one air guide housing (7) which extends at least partially radially around the crankcase (6) in a curved manner being mounted on said cooler unit (5) on the air inlet side and being mounted on the compressor unit (1) crankcase (6) on the air outlet side such that the axial air flow which is generated by said axial fan wheel (9) is at least partially taken in by the air guide housing (7) and at least partially guided around the crankcase (6) in the radial direction so as to reach at least one cylinder (10a) arranged on the air outlet side of said air guide housing (7).