| 摘要 |
A feed system for machine tools in which rapidly changing cutting forces occur in milling machines with an hydraulic piston drive, a position control system and a carriage supporting either the tool or the workpiece for relative movement. The carriage is movably mounted on guides with preloadable bearings shiftably or swivelably. Dry-running friction bearings on the carriage are equipped with an automatically readjusting pressure arrangement, by means of which an adjustable shifting resistance is generated, which corresponds at least to the magnitude of the cutting force occurring. Preferably, the pressure arrangement consists of a pressure piston which may be acted upon by means of an adjustable pressure. In the case of the use of post guides, the bearings are equipped with three slide surfaces mutually displaced by 120 DEG and the pressure piston acts radially on one of the three slide surfaces. The adjustability of the shifting resistance permits chatter-free milling even when slight masses are to be shifted and the cutting forces change greatly. The slide surfaces of the dry friction bearings have sharp edges acting as wipers, permitting use in highly dusty conditions. |
