WORM-RACK TRANSMISSION WITH HYDROSTATIC TOOTH BEARINGS

摘要

1,203,728. Machine tool details. INGERSOLL MILLING MACHINE CO. 22 Feb., 1968 [27 Feb., 1967; 22 May, 1967], No. 8731/68. Heading B3B. [Also in Division F2] A rack and worm transmission 14, 20 with hydrostatic fluid bearings 37 between opposed areas of rack-teeth 17 and the worm-thread 19 comprises fluid-supply passages 45 in the rack communicating with ports 42 containing restrictor valves opening on the face of the side wall 41, and a fluid distributer 40, one wall 43 of which is in sliding hydrostatic engagement with the wall 41 and contains fluid-supply ports 44. The worm is shorter than the rack, and the disposition of the ports 44 is limited to a length of the wall 43 which is shorter than the worm (Fig. 2, not shown); thus, fluid is distributed only to those rack-teeth actually engaging the worm. The fluid-pressure developed in the chambers 64 is used to lessen the clearance in the fluid bearing between the walls 41, 43 by means of pistons 67 acting against a thrust-plate 48. Gear teeth 29 may be cut in the periphery of the worm-thread; these mesh with the teeth of a spiral gear (31) (Fig. 4, not shown) disposed beneath the worm and provided with a suitable power source. Reference has been directed by the Comptroller to Specification 1,112,380.