Especially in the case of fast high-quality elevators, travelling comfort has become an aim of increasing importance, but this question is receiving more attention in the case of other elevators as well. One of the factors affecting travelling comfort is the noise heard in the elevator car. Various noises generated by the elevator equipment reach the ears of passengers in the car. To reduce the noise penetrating into the car, the cabin is provided with sound insulation, but often it is not possible to achieve a sufficient damping of the noise carried into the elevator car by conventional means and at a reasonable cost without making unreasonable compromises relating to the usability of the elevator. The conventional sound insulation used in the walls of the cabin is primarily intended for the suppression of air-borne noise and is therefore in most cases insufficient for the insulation of structure-borne noise. This noise includes the noise generated by roller and sliding guides as they run along the guide rails, and also the noise originating from the bearings of roller guides. This kind of noise tends to be transmitted into the cabin via the guide seat and the car frame. In roller guides, each roller is generally provided with springs permitting roller motion relative to the guide frame. The springs are primarily designed to damp the excitations resulting from the unevenness of the guide rails or junctions of guide rails and causing relatively low-frequency oscillations of the elevator car. For the same reason, sliding guide shoes are provided with springs or elastic spacers to attach the sliding blocks to the guide frame. A significant portion of the higher-frequency oscillations, and especially of the oscillation component propagating as structure-borne noise, is passed through this type of spring systems because the springs of guide rollers and sliding blocks are primarily designed with a view to the oscillation of the relatively large mass of the elevator car. The problem of structure-borne noise is emphasized in self-supporting car solutions with the guides attached directly to the shell of the cabin.
USPTO Backgrounds
USPTO Backgrounds