5results about How to "Reduce low frequency noise" patented technology

This invention relates to the field of vehicles, providing a housing structure, a rear bumper assembly, a vehicle body, and a vehicle. The housing structure includes a housing body with a receiving groove for accommodating a pressure relief valve on a rear side panel. The housing body can be positioned on the outside of the rear side panel of the vehicle, and an exhaust passage communicating with the pressure relief valve is formed between the receiving groove and the rear side panel. The exhaust passage has an exhaust port facing the rear end of the vehicle. When the vehicle is in motion, the airflow outside the vehicle bypasses the housing body and flows towards the rear end of the vehicle. Since the exhaust port of the exhaust passage faces the rear end of the vehicle, the airflow outside the exhaust passage passing through the exhaust port causes minimal pressure changes within the exhaust passage, resulting in minimal pressure differential fluctuations between the exhaust passage and the inner side of the rear side panel. This effectively reduces the frequency and amplitude of the pressure relief valve's flapping action, thereby reducing low-frequency noise generated by pressure differential fluctuations in the acoustic cavity and ensuring passenger comfort.

This invention relates to a high-voltage, capacitor-free, low-noise linear regulator. It comprises a high-voltage switching voltage follower, a self-zeroing error amplifier, and voltage divider resistors. The high-voltage switching voltage follower significantly enhances the system's transient response to load changes and improves power supply rejection in the mid-frequency range. The self-zeroing error amplifier, together with the high-voltage switching voltage follower, forms a global slow loop. The self-zeroing error amplifier employs a ping-pong self-zeroing method, effectively reducing low-frequency flicker noise and offset while ensuring continuous operation in the time domain. This invention introduces a settling phase between the self-zeroing and amplification phases of the ping-pong module, significantly reducing output glitches caused by amplifier settling time. This invention operates stably without an external output capacitor, supports a wide input and output voltage range, and possesses excellent characteristics such as low noise, high power supply rejection, and fast response, making it suitable for various demanding high-voltage power supply applications.

The utility model discloses an air inlet noise reduction structure and gas heating water heater, the air inlet noise reduction structure comprises a noise reduction pipe and noise reduction cotton, the noise reduction pipe is provided with an air inlet end, an air buffer end and a connecting end, the air inlet end is provided with a trumpet-shaped air inlet, the air buffer end is of a round inverted L-shaped structure, and the connecting end is connected with the noise reduction cotton. The joining end is provided with a joining port for joining a premixer; the silencing cotton sleeve is arranged at one end of the air inlet end close to the air inlet. According to the air inlet noise reduction structure, through the structure that the noise reduction pipe is combined with the noise reduction cotton, the noise reduction cotton is used for absorbing noise generated by friction between air and the inner wall of the pipeline in the air inlet process, the air inlet noise is prevented from being further expanded through the pipeline, and through the action of the long and smooth noise reduction pipe, the air inlet noise is further reduced; the ignition deflagration sound of the subsequent water heater and the low-frequency noise generated during small fire combustion are reduced.

This invention discloses a multi-layer composite sound insulation cotton for drain pipes. It comprises, from the outside in, a release paper layer, a first butyl rubber layer, an IXPE foam layer, a second butyl vibration damping layer, and a non-woven protective layer, stacked sequentially. The first butyl rubber layer is made of modified butyl rubber; the IXPE foam layer is made of cross-linked polyethylene foam with an independent closed-cell structure; and the second butyl vibration damping layer is made of high-damping butyl rubber. The sound insulation cotton of this invention achieves low-temperature continuous bonding and initial vibration damping and waterproofing through the first butyl rubber layer; it achieves sound absorption, sound insulation, and heat preservation through the IXPE foam layer; it forms a constrained damping structure with the second butyl vibration damping layer, the first butyl rubber layer, and the IXPE foam layer to suppress pipe vibration and block sound bridge transmission; and it forms a double waterproof structure with the non-woven protective layer and the first butyl rubber layer to prevent external water vapor penetration. It integrates multiple functions such as bonding, vibration damping, sound absorption, sound insulation, heat preservation, waterproofing, and protection.

The application discloses a double-layer noise reduction air guide ring, which comprises an inner air guide ring layer and an outer air guide ring layer. The inner air guide ring layer comprises a circular ring segment, a mounting panel, an inlet flow guide segment and an outlet diffuser segment. The inlet flow guide segment and the outlet diffuser segment are fixedly connected with the two ends of the circular ring segment respectively. The inlet flow guide segment is in a circular arc shape. The mounting panel is fixedly connected with the side of the inlet flow guide segment, which is away from the circular ring segment. The outer air guide ring layer comprises a flat segment, a circular arc segment and a partition plate. The end of the circular arc segment, which is close to the inner air guide ring layer, is provided with an outer layer outlet end. The end of the circular arc segment, which is away from the inner air guide ring layer, is provided with an outer layer inlet end. The mounting panel and the flat segment are provided with a connecting structure. The partition plate is provided with a plurality of partition plates. The resonant cavities between the adjacent partition plates are different in size. The application further discloses a fan comprising the double-layer noise reduction air guide ring. The application has the advantages of high fan efficiency and low air inlet noise.