70results about How to "Suppress vibration noise" patented technology

In accordance with the present invention an aircraft floor panel is provided comprising a honeycomb core element having an upper core surface, a lower core surface, and a core thickness. An upper face sheet assembly is mounted to and seals the upper core surface and includes at least one upper material sheet impregnated with an upper epoxy resin. A lower damping face sheet assembly is mounted to and seals the lower core surface and includes at least one lower material sheet infused with a highly damped lower epoxy resin. The lower damping face sheet assembly dampens vibrational noise.

The invention discloses a polyphase permanent magnet synchronous motor current waveform optimal control method, comprising the following steps of A, current reference value coordinate transformation; B, current multiple proportion resonance regulation; and C, coupling compensation. In the control method, based on polyphase permanent magnet synchronous motor vector control, a polyphase synchronous rotating coordinate system current reference value is transformed to a current reference value of each phase in a polyphase static coordinate system through polyphase coordinate transformation, the current reference value of each phase and a current feedback value of each phase of a motor are respectively subjected to improved multiple superposition proportion resonance regulation, and a resonance separation method is introduced, decoupling is realized by feed-forward compensation, and floating tracking and harmful subharmonic restraining for highly dynamic property fundamental waves and usable subharmonic are realized. The method can restrain the adverse impacts, such as motor loss, torque ripple and vibration noise, caused by a harmful harmonic current of the polyphase motor, can explore the positive effects of the usable harmonic current, gives full play to the advantages of the polyphase motor and improves the system performance.

The invention discloses an adjustable damping device for a ship base. The adjustable damping device for the ship base comprises webs (1), a flat plate (2), a vibration isolating cushion (3), a spring assembly (4), a base (5), base stand bars 5 (1), a base support 5 (2), vertical bolts (6), a supporting block (7), transverse bolts (8), an arc-shaped toggle plate (9), a foot pad (10), fixing plates (11) and fixing bolts (12). By the adoption of the adjustable damping device for the ship base, a whole ship can be better hidden, and the comfort of the whole ship is improved. The adjustable damping device for the ship base has the advantages of being reasonable, simple, easy to manufacture and low in cost.

A silent chain transmission utilizes two different kinds of link plates. In a first kind of link plate, the inner flank pitch line is farther than the outer flank pitch line from the chain pitch line. In a second kind of link plate the inner flank pitch line is closer than the outer flank pitch line from the chain pitch line. Every four successive links includes at least one link composed of one type of link plate and at least one link composed of the other type of link plate.

A heat resistant air hose which is excellent in oil-bleeding resistance and causes reduced vibration noise is provided. The heat resistant air hose has an inner layer formed of an inner layer material comprising silicone rubber as a major component thereof; and an outer layer provided on an outer periphery of the inner layer and formed of an outer layer material comprising acrylic rubber as a major component thereof, and the acrylic rubber contains not less than 50 wt % of ethyl acrylate and has a dissipation factor (tanδ) of not less than 0.09 at 150 ° C. and a storage elastic modulus (E′) of not less than 7.0 MPa.

The invention discloses a sandwich plate vibration absorbing structure based on micro local resonance subarrays. The sandwich plate vibration absorbing structure comprises a sandwich plate and at least one resonance subarray arranged in the sandwich plate, wherein each resonance subarray comprises a pair of parallel installation limiting supports and a plurality of vibrator units suspended between the installation limiting supports, and the vibrator units are used for absorbing low-frequency vibration energy from outside. The resonance subarray is arranged in the sandwich plate, so that the sandwich plate has a good sound insulation property at the low frequency, particularly near the low order natural frequency of the sandwich plate. The sandwich plate vibration absorbing structure has the advantages of low cost, simple control system and high reliability.

The invention discloses a rotor core of a segmented skewed-pole motor and a permanent magnet synchronous motor. The rotor core comprises a plurality of rotor core sections which are mutually staggeredat a preset angle, and the rotor core sections are formed by laminating rotor punching sheets; magnetic steel grooves are distributed in each rotor core section along the circumferential direction, and magnetic steel can be arranged in the magnetic steel grooves; a plurality of axially-penetrating auxiliary grooves are formed in the outer circumferential face of each rotor core section, the positions and/or the section shapes of the auxiliary grooves in each rotor core section are not completely the same, and the auxiliary grooves are used for restraining torque pulsation and vibration noisegenerated when the motor rotates. According to the scheme, the plurality of axially-penetrating auxiliary grooves are formed in the outer circumferential surface of each rotor core section; and the positions and/or the section shapes of the auxiliary grooves on the rotor core sections are not completely the same, so that the torque pulsation and the radial electromagnetic force generated by the rotor core of each section are respectively suppressed at a relatively low level, the overall torque pulsation and the radial electromagnetic force of the motor are reduced, and the vibration noise of the motor is effectively suppressed.

The invention discloses a noise-reduction damping device of a train wheel. The structure of the noise-reduction damping device is characterized in that a noise shielding plate is formed by alternately bonding and superimposing at least two circular ring-shaped metal plates (3a,3b) and at least one circular ring-shaped viscoelastic damping layer (4); the outer circumference of the noise shielding plate is fixed on the rim (1a) of a wheel (1) through an outer mounting ring (2) by screw threads; and the inner circumference is clamped on a hub (1c) and an axle (1d) through a clamping ring (10). The damping device has good noise-reduction effect and does not change the shape of the main body of the wheel, thereby being easy to popularize and implement.

The invention provides a terahertz low-noise communication system transmit-receive front end based on GaAs monolithic integration, and belongs to the technical field of terahertz wireless communication, the terahertz low-noise communication system transmit-receive front end comprises an intermediate frequency circuit and a terahertz circuit, the terahertz circuit comprises a local oscillator frequency tripler, a local oscillator homodromous 3dB filtering coupler, a radio frequency 180-degree filtering coupler and two terahertz GaAs monolithic integration subharmonic mixers; the local oscillator equidirectional 3 dB filtering coupler and the radio frequency 180-degree filtering coupler comprise an annular cylindrical resonant cavity and four rectangular waveguides, the annular cylindrical resonant cavity is divided into a large fan annular resonant cavity and three small fan annular resonant cavities through four fan annular grooves, and the central angle of the large fan annular resonant cavity is twice that of the small fan annular resonant cavities; and the four rectangular waveguides are correspondingly connected with the four sector-ring-shaped resonant cavities respectively. According to the invention, the local oscillator same-direction 3dB filtering coupler and the radio frequency 180-degree filtering coupler which have coupling and filtering functions are adopted, so that the low local oscillator noise suppression transceiving front end is realized.

The invention discloses a device and method for actively suppressing the jitter of a test optical path. The active suppression test optical path jitter device is composed of a beacon light, a beam splitter, a piezoelectric fast mirror, and a control computer. The overall method is to emit beacon light at the detection end of the test optical path, use an optical splitter to couple and incorporate the test light, and reversely transmit it to the light input end of the test optical path in the test optical path. A piezoelectric fast mirror, a beam splitter and a detection camera are installed at the light incident end of the test light path. The beacon light is separated into the test light by the beam splitter, and the spot jitter is collected by the detection camera, which is the test light path jitter. The control computer uses the centroid algorithm to calculate the off-target amount of the beacon light and controls the vibration compensation of the piezoelectric fast mirror. The invention can effectively suppress the jitter caused by the platform and the like in the test light path.

The invention relates to a low-noise centrifugal pump with a staggered non-uniform symmetric impeller/guide vane structure. According to the low-noise centrifugal pump with the staggered non-uniform symmetric impeller/guide vane structure, a conventional uniform and symmetric arrangement mode of impeller vanes is broken through, the arrangement angles between impellers and adjacent vanes of the guide vanes are designed according to the periodic trigonometric function relation, the arrangement angles between the vanes conform to the periodic distribution rule, the superimposed effect of pressure waves generated by dynamic and static interference between fluid at outlets of the impellers and the guide vanes is restrained, and the pressure pulsation amplitude is reduced. Meanwhile, rib plates are arranged between the impellers and the guide vanes, the impellers and the guide vanes are arranged in a staggered mode through the rib plates, the flow of liquid flowing out of impeller runners and guide vane runners at the same time is reduced, the dynamic and static interference effect between the movable vanes and the static vanes of the centrifugal pump is further weakened, the purpose of reducing vibration noise is achieved, and on the premise that the efficiency is not influenced, the operation stability of the centrifugal pump is improved.

The present invention provides a control method for inhibiting single-phase capacitor run motor vibration noise. The circuit of the method comprises a primary winding, a secondary winding, a start capacitor and an adjustable run capacitor. The induction electromotive force of the secondary winding when the primary winding is powered and the secondary winding is disconnected and the induction electromotive force of the primary winding when the secondary winding is powered and the primary winding is disconnected are detected when a motor is in a no-load operation, and the effective turn ratio of the primary winding and the secondary winding is obtained. Rated voltage is applied to the motor to allow the motor to drive a load to run, a start capacitor is disconnected after normal running, the adjustable run capacitor is connected, the voltage of the primary winding, the secondary winding and the adjustable run capacitor at that time are detected, the ovality information of a gap magnetic field is obtained, the capacitance value of the adjustable run capacitor is changed according to the information, the vibration noise in common single-phase capacitor run motor load running can be effectively inhibited, the adjustable run capacitor can be changed according to different loads dragged by the motor, and the vibration noise is small when multiple types of loads are dragged by the motor.

This invention provides a seatbelt retractor capable of effectively suppressing occurrence of a vibration and a noise, a base frame (12) is composed of a first frame (16) for rotatably supporting a spool, and a second frame (17) to be attached to a motor vehicle body. The first frame (16) is composed of a pair of flat plate-shaped first and second supporting members (18 and 19), and spacing members (20, 21, 22, and 23) that couple the pair of the first and second supporting members (18 and 19). Further, the degree of the parallelization of the pair of the first and second supporting members (18 and 19) is obtained with high accuracy by the spacing member. Accordingly, an assembling accuracy for a spool can be improved and, thereby, a vibration and a noise caused by a rotation of the spool can be suppressed.

The invention provides an integrated washing and drying machine with a drying unit with excellent installation performance and a good universality. The integrated washing and drying machine comprisesa machine body, a cylinder body and the drying unit, wherein the cylinder body is arranged in the machine body, and the drying unit is arranged in the machine body and communicated with the cylinder body. The integrated washing and drying machine is characterized in that the drying unit comprises a drying main assembly, an air suction connector assembly connected to the drying main assembly and anair supply connector assembly connected to the drying main assembly.

The invention provides a vibration noise smoothing method and system for attitude time series data. The method comprises the following steps of dividing original attitude time sequence data accordingto a preset time window to form the multiple segments of attitude time sub-sequence data, conducting vibration noise smoothing processing on each segment of attitude time sub-sequence data at the sametime. The processing efficiency can be improved, high real-time performance is achieved, the vibration noise in the attitude time sub-sequence data can be restrained, and smooth transition of continuous same-working-condition and different-attitude data is supported.