GB906818A - Hydrostatic bearing - Google Patents

Abstract

906,818. Machine-tool details. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 1, 1960 [April 2, 1959], No. 11318/59. Class 83 (3). [Also in Group XXXIV] In a fluid bearing means are provided for measuring the variation in resistance to flow of fluid through a clearance space 6 and for varying the supply pressure to maintain constant the flow of fluid through the space. The resistance to flow through a restriction 2 is represented in Fig. 3 by a resistance R 1 and that through the clearance space 6 by a resistance R 2 . The pressure P s of the fluid supplied from a valve 10 is connected to one end of the valve casing and the pressure P 1 of the fluid passing to the clearance space is connected to the other end of the valve casing. Since the areas of valve spools 13, 14 are in the ratio 2: 1 the pressure P 1 = ¢ P s . The resistance R 2 is thereby maintained as a constant proportion of R 1 , say 0.3 to 0.7 R 1 . Two such systems may be employed on the slide of a lathe, milling machine or profile checking machine as shown in Fig. 4, there being no need to ensure a fine finish on the main bearing areas 33, 34, 35, 36. To prevent damage in case of sudden loads or failure of the fluid pressure supply, pads 50, Fig. 5, may be used to convey the fluid to the auxiliary bearing surfaces 37, 39, 38, 40 of Fig. 4. The pads 50 are carried on rods 51 which can be moved axially against springs 54 if the pads contact the slideway. Such pads can be used on dividing heads, sighting instruments and vertical bearings. Additional conventional pads may also be provided.