33results about How to "Anechoic frequency bandwidth" patented technology

A pressure self-adaptation low-frequency broadband elastic resonance noise-abatement device comprises a liquid pipeline. An opening in the pipe wall of the liquid pipeline is communicated with a sealing cavity on the outer side through a cavity neck, the opening end of the cavity is sealed by an elastic wall board and a sealing pad, a flange part is arranged at the end of a shell of the cavity, the elastic wall board and the sealing pad are connected with the flange part of the cavity in a fastening mode, the other side of the elastic wall board is connected with a compression ring in a sealing mode, or the other side of the elastic wall board is connected with a hollow shell with a backpressure cavity in a sealing mode, high-pressure gas or liquid is filled into the backpressure cavity, and when liquid is filled into the backpressure cavity, viscoelastic damping rubber or noise absorbing rubber needs to be bonded on the inner wall surface of the backpressure cavity. The pressure self-adaptation low-frequency broadband elastic resonance noise-abatement device can achieve low-frequency noise abatement of the liquid pipeline and is small in structure size, the pressure self-adaptation low-frequency broadband elastic resonance noise-abatement device is used according to noise-abatement frequency combination, therefore, broadband noise abatement can be achieved, and the using requirement for bearing the pressure of a flow channel in the pipeline can be also met.

The invention discloses a frequency-adjustable type single-pole multi-frequency resonance muffler. According to the frequency-adjustable type single-pole multi-frequency resonance muffler, a pluralityof noise elimination peak values are in a concerned frequency band, and the noise elimination frequency range can be adjusted. According to the single-pole muffler, a shell part is composed of a fixed shell and a movable shell, and the movable shell can move in a certain range. An even number of pieces of fixed inserting plates and movable inserting plates (above six pieces) are axially insertedin a hollow cavity formed by an exhaust pipe and the two shells, the fixed inserting plates and the movable inserting plates are tightly attached to one another to divide the hollow cavity into an even number (above six) of parallel resonant cavities, a different number of noise elimination holes are formed in the exhaust pipe in the axial direction to form an even number (above six) of parallel resonant cavities, and the number of the cavities is equal to the number of the resonant frequencies. A plurality of coupled holes are formed in the fixed inserting plates, and the fixed inserting plates with the coupled holes and the fixed inserting plates without the coupled holes are arranged at intervals. According to the design, the movable shell can be adjusted to change the range of the noise elimination frequency band. According to the frequency-adjustable type single-pole multi-frequency resonance muffler, a serial-parallel resonant noise elimination structure is constructed in a limited space of the single-pole muffler, and the noise elimination effect is greatly improved.

The invention relates to an automobile electrical machine heat dissipation fan noise-reduction and anti-vibration system. An electrical machine includes a pedestal, an electrical machine housing which is arranged on the pedestal, a rear cover which is in fixed connection to the electrical machine housing, heat dissipation fins which are evenly disposed on the electrical machine housing, a drive shaft which is disposed inside the electrical machine housing and an electromagnetic coil. An apparatus includes a hydraulic coupler which is in transmission connection to the drive shaft, heat dissipation blades which are evenly disposed in the periphery of a turbine of the hydraulic coupler, an electromagnetic clutch which brings a pump impeller of the hydraulic coupler and the drive shaft into transmission connection, a bypass cooling pipeline which is arranged in the electromagnetic coil, an electromagnetic valve which is disposed in the bypass cooling pipeline, and an ECU controller which is separate and electrical connection to the hydraulic coupler, the electromagnetic coupler and the electromagnetic valve. Compared with prior art, according to the invention, the system herein realizes heat dissipation by combining oil cooling and air cooling, in combination with a micropunch noise elimination structure, can effectively noise of an automobile electrical machine heat dissipation fan and reduce self vibration.