Variable-acceleration curved-surface spiral gear transmission mechanism for variable-speed mass damping system

Abstract

The invention provides a variable acceleration curved surface spiral gear transmission mechanism for a variable speed mass damping system. An orthogonal orbital planetary gear set moves along the parallel arc guide rails, so that a concave curved surface spiral gear and a convex curved surface spiral gear are meshed at different radiuses, the continuous change of the gear ratio is realized, and the purpose of changing the acceleration of an additional mass block is achieved. The spiral curve limiting guide grooves are formed on the surfaces of the concave curved surface spiral gear and the convex curved surface spiral gear in advance, the change speed of the gear ratio is adjusted by designing different spiral curves, and the change speed of the acceleration of the additional mass block iscontrolled. According to the mechanism, by adjusting the gear ratio of the gearbox and controlling the acceleration of the additional mass block, when the earthquake displacement of a main structuregets closer to the peak value, the inertia damping force provided by the mechanism is larger, and when the main structure vibrates at a small amplitude near a balance position, the gear ratio of the main structure becomes smaller, and the stroke of the additional mass block becomes smaller, so that the service life of a spring, a viscous damper or other components, can be prolonged.

Description

technical field [0001] The invention belongs to the technical field of passive control of bridge structures, relates to bridge damping technology, and particularly relates to a variable-acceleration curved-surface helical gear transmission mechanism for a variable-speed mass damping system. Background technique [0002] When the long-span suspension bridge undergoes an earthquake, the longitudinal displacement of the main girder is large, and the inertial force of the main girder will be transmitted to the cable tower, causing the cable tower to bear a large bending moment. At present, the usual shock absorption methods are: (1) using viscous dampers between the main beam and the anchorage or between the main beam and the cable tower; (2) using anti-seismic bearings; (3) using a variable speed mass damping system. Although the conventional tuned mass damper (TMD) has a certain damping function, its applicable frequency range is narrow and requires a large additional mass, so...

AI Technical Summary

Problems solved by technology

Although the conventional tuned mass damper (TMD) has a certain damping function, its applicable frequency range is narrow, and it needs a large additional mass block, and the seismic damping effect applied to bridges is not obvious

The variable speed mass damping system has a good shock absorption effect, but since the transmission ratio of the variable speed transmission mechanism is fixed, in order to reduce the structural response under the maximum earthquake force, a larger transmission ratio needs to be designed, but under wind load or temperature Under normal loads such as changes, the stroke of the additional mass block is too large, which will reduce the service life of the spring and viscous damping components

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