Elastic Pneumatic Cylinder for Vibration Suppression in Slip Bearings

Abstract

Vibrations in machines and their effect on performance are analyzed. One of the main sources of vibrations in machine parts is the slip bearing, in which the shaft passes through a bush with some gap. Impact arises when that gap closes. The operation of vibroprotective systems based on an elastic shock absorber is considered. The influence of the rigidity of the elastic element on the performance of slip bearings is analyzed. An elastic pneumatic element of increased rigidity is proposed, in the form of a cylinder with limited radial deformation. This element is able to center the shaft relative to the geometric axis of the bearing under the action of a radial load, thanks to the difference in contact area of the external surface of the bearing housing and the surface of the elastic cylinder. A method is developed for increasing the contact of the elastic element (the pneumatic cylinder with limited radial deformation) and the surface through which the external load is transmitted, with specified bearing parameters: the cylinder length; and the excess gas pressure within the cylinder. The shaft is assumed to fit in the bearing without a gap and the cylinder casing is regarded as inextensible. The deformation and rigidity of the elastic pneumatic cylinder with limited radial deformation are found to depend on the cylinder length and the excess gas pressure within the cylinder cavity. The mathematical formulas obtained permit the determination and specification of the parameters of the pneumatic element (the cylinder length and the excess gas pressure within the cylinder) as a function of the slip bearing’s operating conditions.