| 摘要 |
PROBLEM TO BE SOLVED: To reduce noises in the case of a rotary motion by absorbing operating sounds generated by a turning motor and an epicycle reduction mechanism. SOLUTION: A sound absorbing cover 41 is formed of a lower-side housing section sound absorbing cover 42, an upper-side housing section sound absorbing cover 43, a turning-motor section sound absorbing cover 44, a valve-section sound absorbing cover 45 and an oil-drainage pipe section sound absorbing cover 46, and a housing 9 and the outer circumferential surface of a turning motor 13 are covered. Thus, the sound absorbing cover 41 can absorb the operating sounds of both the turning motor 13 and the epicycle reduction mechanism, and can reduce noises in the case of rotating operation. Since the sound absorbing cover 41 is divided and installed into the sound absorbing covers 42-46 and these covers are assembled integrally, the housing 9 and the turning motor 13 can be covered with the sound absorbing covers 42-46 having simple shapes.
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