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| Illustration 1 | g02162008 |
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Swing drive (1) First stage carrier (2) First stage planetary gear (3) Second stage carrier (4) Ring gear (5) Second stage planetary gear (6) Roller bearing (7) Roller bearing (8) Pinion shaft (11) First stage sun gear (12) Second stage sun gear (14) Housing (15) Bearing gear (swing gear) | |
The right swing drive and the left swing drive are identical in construction and operation. As a typical example, the description is given for the left swing drive.
The swing drive consists of a series of planetary gears. The planetary gears reduce the rotational speed of the swing motor. The swing motor is bolted to the top of the swing drive. The swing drive is bolted to the upper structure. The teeth of the swing drive output pinion shaft (8) engage with bearing gear (15) of the swing bearing. The pinion shaft (8) rotates around bearing gear (15). This causes the machine to swing. Bearing gear (15) is attached to the lower structure.
The swing drive is divided into the following two groups :
- The first group is a double reducer of motor speed. The first stage reduction group consists of the following components : first stage sun gear (11), first stage planetary gear (2), ring gear (4) and first stage carrier (1). The second stage reduction consists of the following components : second stage sun gear (12), second stage planetary gear (5), ring gear (4) and second stage carrier (3).
- The second group is the group for reduced output speed of the motor. The second group consists of the following components : roller bearing (6), roller bearing (7) and pinion shaft (8). The roller bearings are installed in housing (14) and the roller bearings support pinion shaft (8).
The swing speed is reduced by a ratio of teeth on the sun gear to ring gear teeth by planetary reduction. Since the sun gear is inside of the ring gear, the swing drive is more compact than reduction units with external teeth.
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| Illustration 2 | g02268295 |
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Operation of the first stage planetary assembly (1) First stage carrier (2) First stage planetary gear (4) Ring gear (11) First stage sun gear (16) Shaft (first stage planetary gear) | |
The swing motor output shaft is splined to first stage sun gear (11). First stage planetary gears (2) of first stage carrier (1) mesh with first stage sun gear (11). When first stage sun gear (11) rotates counterclockwise, first stage planetary gears (2) rotate in a clockwise direction on shafts (16). First stage planetary gears (2) move counterclockwise around ring gear (4). Ring gear (4) is bolted to housing (14). First stage carrier (1) rotates counterclockwise.
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| Illustration 3 | g02162021 |
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Swing drive (1) First stage carrier (2) First stage planetary gear (3) Second stage carrier (4) Ring gear (5) Second stage planetary gear (6) Roller bearing (7) Roller bearing (8) Pinion shaft (11) First stage sun gear (12) Second stage sun gear (17) Inner circumference | |
Splines on inner circumference (17) of first stage carrier (1) engage with the splines on second stage sun gear (12). This causes second stage sun gear (12) to rotate counterclockwise when the first stage carrier rotates. Second stage planetary gears (5) turn clockwise on the shafts and second stage planetary gears (5) move in a counterclockwise direction around ring gear (4). Second stage carrier (3) turns counterclockwise. The splines on the inner circumference of second stage carrier (3) engage with the splines of pinion shaft (8). When the second stage carrier turnscounterclockwise, pinion shaft (8) rotates counterclockwise.
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| Illustration 4 | g02162024 |
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Rotation of pinion shaft (8) Pinion shaft (15) Bearing gear (swing bearing) (18) Position of moving pinion shaft | |
Pinion shaft (8) engages with bearing gear (15) on the inner circumference of the swing bearing. As pinion shaft (8) rotates counterclockwise, pinion shaft (8) moves in a clockwise direction around bearing gear (15). Bearing gear (15) is bolted to the lower structure. This causes the upper structure to swing to the right (clockwise rotation).