| 摘要 |
A high speed machining system (10) including a machine tool (16) mounted on a hollow shaft (14) rotatable at high speeds and the tool (16) being operable at high feed rates. Liquid cutting coolant (22) flows to the tool (16) through the hollow shaft (14) to flush away debris from the tool (16) and for cooling the system (10). Drive means (18) including windings rotate the shaft (14), which is supported by bearings. The windings and bearings have the characteristic of long life in an environment free of liquid cutting coolant (22). The high speed machining system (10) includes a seal assembly (30) to prevent the liquid (22) from entering the liquid-free environment of the bearings and the windings. The seal assembly (30) includes annular means for urging (52) a stationary sealing face (42) against and in annular contact with a rotating hardened sealing surface (38) to form an annular primary seal (54) for isolating the liquid (22 ) from the bearings and windings. First means for sealing (66) are positioned between an enlarged diameter portion of an annular face seal (40) and an inner cylindrical wall (60) of an annular retainer (58) to suppress leakage of liquid (22) therebetween. Second means for sealing (68) are positioned between an outer cylindrical wall (62) of the retainer (58) and a bore (56) defined within a housing (12) to form a tertiary seal (68) and suppress leakage of liquid (22) therebetween. In cooperation, the annular primary seal (54) and the secondary and the tertiary seals (68) cooperate to substantially eliminate leakage of liquid (22) outside the seal assembly (30) when the liquid (22) is flowing through the hollow shaft (14) to the machine tool (16) at sufficiently high pressures and volumes to remove debris from adjacent the machine tool (16), and to cool the high speed machining system (10) while the shaft (14) rotates at high speed. In alternate embodiments of the invention, different structures of seal interface are disclosed. Each has the attribute of using the pressure of liquid (22) flowing in the liquid path to augment the annular means (52) for urging the annular face seal (40) against and in annular contact with the hardened sealing surface (38) to form the primary seal (66) therebetween.
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