32results about How to "Reduce acoustic noise" patented technology

The invention provides a control IC, controlling a switch power supply (4) providing a driving voltage (Vout) for one end of an LED string (6) through intermittence drive. A pulse modulation machine (19) generates a pulse signal (Spwm) whose duty ratio is adjusted during a lightening period, enabling a detection voltage (VLED) of an output voltage (Vout) of the switch power supply (4) to be consistent with a regulated voltage references (Vref). A driver (28) drives a switch transistor (M1) of the switch power supply (4) based on the pulse signal (Spwm). The pulse modulation machine (19) enables the duty ratio of the pulse signal (Spwm) to descend with time during the time from the lightening period to a quenching period. The control IC (100) inhibits the noise of coils at the time of PWM driving.

The invention relates to a capping device of a conduit mouth of a ship body, which comprises a cylinder body 1, cover plates 2 and a cover plate driving device 3, wherein the 2-6 cover plates 2 which can realize 90-degree rotation are symmetrically distributed on the vertical circular section close to a cylinder mouth of the cylinder body 1 as far as possible, in the cylinder body 1, along the central line of the circular section, the rotation axial lines of the cover plates 2 are parallel to the central line of the circular section, and all the cover plates can just seal the vertical circular section of the cylinder body when the cover plates are closed; a driving rotating shaft 4 and a driven rotating shaft 5 are connected at the two ends of each cover plate 2, the driving rotating shafts 4 and the driven rotating shafts 5 are respectively fixed on the cylinder body 1 through bearing seats 6, the axial lines are superimposed, and the driving rotating shafts and the driven rotating shafts can rotate along the axial lines respectively; and the cover plate driving device 3 is fixed on the cylinder body 1 and can drive the driving rotating shafts to drive the cover plates 2 to realize the 90-degree rotation. The capping device can reduce acoustic noise generated by the open conduit mouth and improve the working conditions of a ship-borne acoustic detection system; and the structure is simple and reliable, the conventional relay control can be adopted, the operation and the maintenance are convenient, and the cost is low.

A damper assembly comprising: a body defining a continuous fluid path extending between a first opening and a second opening; and a damper rotatable within the body to control fluid flow through the subject. The body includes an engagement edge extending circumferentially over the inner surface of the body. The damper is rotatable relative to the body to sealingly engage the outer edge of the damper with the engagement edge. The engagement edge of the body can be oriented on the inner surface such that the surface area of ​​the outer edge engaging the engagement edge increases progressively as the damper is rotated to seal the damper to the body.

The invention relates to a control method for a motor (13) of a hybrid power transmission assembly (1) to charge a storage battery (17) of a certain power for electric traction. The control method is configured such that the electric machine (13) extracts an extracted torque from the heat engine (11) with an upper limit, and the upper limit has been subtracted from a driver's setpoint to comply with acoustic constraints. According to the invention, when the driver's setting is greater than a torque threshold, the method limits the extracted torque to a lower limit to ensure charging of the battery (17) for electric traction.