| 摘要 |
An automatic balancing device (50; 150; 150a; 250; 350) for counterbalancing an out-of-balance mass present in a body (12) which is rotatable about an axis (18; 118; 118a; 218; 318), the automatic balancing device (50; 150; 150a, 250; 350) comprising a plurality of counterbalancing masses (60, 70; 160, 170, 190; 160a, 170a; 264, 274; 374), each of which is movable in a circular path about the axis (18, 118, 118a, 218, 318) so as to generate a balancing force (FB; FB1, Fb1; FB2). In use, the balancing forces (FB; FB1, Fb1; FB2) combine to produce a resultant balancing force (FR) which is variable between a minimum value and a maximum value. The automatic balancing device (50; 150; 150a; 250; 350) is configured so that, at a first speed of rotation of the body (12) about the axis (18; 118; 118a; 218; 318), the movement of at least one of the counterbalancing masses (60, 70; 160, 170; 160a, 170a; 264, 274; 374) is restrained so that a substantially constant, non-zero resultant balancing force (FR) is produced, the said resultant balancing force (FR) being freely movable about the axis (18; 118; 118a; 218; 318). At a second speed of rotation of the body (12) about the axis (18; 118; 118a; 218; 318), the counterbalancing masses (60, 70; 160, 170, 190; 160a, 170a; 264, 274; 374) are free to adopt a position in which the out-of-balance mass is counterbalanced. The device (50; 150; 150a; 250; 350) allows at least partial counterbalancing of the out-of-balance mass at speeds below the critical speed of the system in which it is used and this reduces the maximum excursion of the body (12) through the critical speeds. |
