A winch provided with an automatic shifting planetary gear transmission comprises a power mechanism motor or a hydraulic motor (1), a transmission (2), a winding drum (3), a brake (4), a rack (5) and a sensor (6), and is characterized in that a flange at the end of the power mechanism (1) is fixed on a left rack (5.1) through a joint (1.1) by bolts;
- the transmission (2) is arranged in the winding drum (3), conical or cylindrical reinforcing sections I (2.1 a) and II (2.1 b) are arranged on the outer diameters of the two sides of a transmission shell (2.1) with the tapered inner diameter, the outer diameter of the left reinforcing section I (2.1 a) is smaller than that of the right reinforcing section II (2.1 b), and the left end face of the transmission shell (2.1) is fixed on the rack (5.1) through bolts, a plurality of axial grooves (2.1 a1) are formed in the upper half part of the reinforcing section I (2.1 a), oil pipes for gear shifting and lubricating and strong and weak electric lines enter the lead-out transmission shell (2.1) from the axial grooves (2.1 a1) through a rack hole (5.1 a), and a transmission right end cover (2.1 c) is fixed on the end face of the reinforcing section II (2.1 b) through bolts, a bearing (7) arranged in the central hole is combined with an n-stage planetary gear overhead output shaft (2.2 b1), a bearing (7) with an inner ring inner spline arranged on the inner diameter of a hollow output shaft (2.2 b1) is combined with a driving shaft outer spline (2.31), and a half coupling (2.7) is arranged between the hollow output shaft (2.2 b1) and a winding drum (3) for connection, a pressing plate (2.74) is arranged on the left end face of the half coupling (2.7), the gap between a half coupling driving member (2.72) and a driven member (2.73) is increased, so that the hollow output shaft (2.2 b1) can freely rotate by an angle alpha, and the angle alpha is multiplied by the angle alpha of one tooth pitch p of an n-stage planetary gear (2.2) transmission ratio i gt=n-stage planetary gear left clutch II (2.5 b1);
- a bearing (7) arranged on the inner diameter of the left side of the winding drum (3) is combined with the outer diameter of a transmission shell reinforcing section I (2.1 a), a right end cover (3.2) of the winding drum is connected with a rope winding part drum body (3.1) through bolts, a bearing (7) arranged on the center hole of the right end cover (3.2) of the winding drum is combined with a right hollow support frame (5.2 a), and the hollow support frame (5.2 a) is fixed on a right rack (5.2), the right rack (5.2) is bolted to a frame cross member (5.3) and a base (5.4);
- a driving shaft (2.3) provided with external splines penetrates through central holes (2.2 a1) of each central sun gear, a bearing (7) arranged on the left side is installed on a rack (5.1), a bearing (7) arranged on the right side is installed in a hollow support frame (5.2 a), and a coupler (1.2) arranged at the end part of the left side is connected with a power mechanism (1), The clearance between a coupling driving part (1.21) and a coupling driven part (1.22) is increased, so that the driving shaft can freely rotate by more than or equal to the angle of one pitch p of a driving shaft power output gear (2.3 a);
- a clutch I (2.4) and a displacement sensor (6.2) are arranged on the left side of a first-stage planetary gear (2.2) of the transmission (2);
- a clutch gear shifter (2.5) is arranged between each planetary gear (2.2), and a planetary gear carrier (2.2 b) on the left side is connected with a central sun gear (2.2 a) on the right side through a clutch gear shifter execution unit tubular member (2.5 b), a gear clutch shifter drive unit II (2.5 a) selected by the gear shift command drives a clutch shifter execution unit tubular member (2.5 b) sleeved on a driving shaft to move to the right, a left clutch II (2.5 b1) is separated, and a driving shaft power output gear (2.3 a) positioned in the clutch shifter execution unit tubular member (2.5 b) on the right is combined with a right central sun gear (2.2 a), a power mechanism (1) drives a selected gear central sun gear (2.2 a) to an n-stage planetary gear carrier (2.2 b) through a driving shaft (2.3) to drive a winding drum (3) to rotate, a displacement sensor (6.2) is arranged between each stage of planetary gear (2.2) and connected with a programmable logic controller (PLC), the PLC controls an indicator lamp and an alarm, receives and sends out instructions, and the automatic gear shifting is completed through programming control.