GB1072684A - Improvements in or relating to fluid bearings - Google Patents

Abstract

1,072,684. Drilling. INTERWOOD Ltd. Dec. 9, 1964 [Dec. 10, 1963], No. 48773/63. Heading B3C. [Also in Division F2] A power unit for a machine tool, e.g. a drilling machine, comprises an electric motor 45, 46 having a power-output shaft or spindle 14 that is supported in a housing 10-13 by fluid bearings wherein pressurized fluid, e.g. air, flows axially from a plurality of radial nozzles 22 through annular spaces 21 between fixed sleeves 19, 20 and journals 17, 18 to escape through vents 47, 48 and an aperture 15 in the housing adjacent a chuck 16 for a rotary cutter or drill. Axial thrust on the shaft 14 is taken up by pressurized fluid flowing radially from a plurality of axial nozzles 35 through spaces 32 between a fixed thrust-plate 27, the journal 18 and a brake plate 30 attached to the end of the shaft 14. A vent 37 in the plate 27 allows fluid to escape from an annular clearance-space 31 for the shaft 14. Fluid enters the nozzles 22. 35 through ports 24, 26, 36 in the housing, and annular channels 23, 25, 33 in the sleeves 19, 20 and the plate 27 respectively, the nozzles 35 being connected to the channel 33 by radial bores 34. A plate 39 having a friction lining 39a can be pressed against the plate 30 by manual actuation of a lever 42 pivotally connected to an axially-movable shaft carrying a plate 40 to which the plate 39 is attached by bolts passing through compression springs 41, whereby rotation of the shaft 14 is prevented or checked. A second embodiment of the power unit, Fig. 2 (not shown), differs from that shown in Fig. 1 chiefly in that the nozzles 22, 35 are connected to a common fluid-supply passage (52) in the housing. Rotation of the shaft 14 can be prevented or checked by a pneumaticallyoperated brake comprising a pair of brakeshoes (57) of the caliper-type provided with friction linings (56) that engage with a drum (54) attached to the shaft adjacent the plate 27. The brake is held " on " by a spring (not shown in the drawing) and released by a pneumatic piston-and-cylinder device (not shown in the drawing) that is actuated when the motor 45, 46 is started and fluid, e.g. air, is supplied to the passage (52), said device being provided with a switch for controlling the motor starter. The said device may be controlled by a manuallyoperated valve. Fluid escaping through the aperture 15 may serve to remove waste material in the region of the cutter or drill.