Spindelvorrichtung mit eingebautem Motor

摘要

A spindle device with a built-in motor comprises a casing (18), a working spindle (26) having a large radius portion (21) formed with a bore (28) and a small radius portion (22) extending from the large radius portion (21), the large radius portion (21) being housed in the casing (18), and the small radius portion (22) protruding from the casing (18) and having a working tool (24) mounted thereon, a cylindrical motor rotor (33) attached to an inner surface of the large radius portion (21) of the working spindle (26), a fixed shaft (36) provided in the casing (18) and loosely inserted into the motor rotor (33), and a motor stator (38) mounted on an outer surface of the fixed shaft (36) opposed to the motor rotor (33). The casing (18) is formed with an air passageway (49) having a plurality of injection nozzles (48, 49) which are open at an inner surface of the casing (18) opposed to an outer surface of the large radius portion (21) of the working spindle (26). The working spindle (26) that is rotating is supported by supplying air consecutively from the injection nozzles (48, 49) to a narrow space (50) formed between the inner surface of the casing (18) and the outer surface of the large radius portion (21) of the working spindle (26).