Скачать или смотреть Lego Technic orrery version 2

This is a Lego orrery I put together some time ago. It features a 365-day year, a 30-day lunar month, and a mechanism to keep the earth’s axis pointing the same way throughout the year.

I do admit to using non-standard Lego parts—the earth and moon are marbles held on with poster putty and the sun is a stress ball. Other than that everything is Technic parts. The large base bearing with the 140-tooth ring gears is copied from Lego's Rough Terrain Crane (set 42082).

The 1:365 ratio for the year is achieved as follows: the input shaft that turns once per “day” is connected to one input side of a 28-tooth differential, and the output connects to the 140-tooth ring gear in the base through a worm gear and 36-tooth gear. This achieves a ratio of 360:1 (2 from the differential, 36 from the worm gear arrangement, and 5 from the 28:140 pair), but the 36:1 gear also feeds back into the other side of the differential, subtracting one turn every 72 turns, so the overall ratio there is 73:1. Combined with the 5:1 from the large ring gear the total is 365:1. Conveniently, the shaft that turns the earth’s axis is also geared down 5:1, so the 73:1 shaft is also connected to that.

I’m working on a Lego clock that I hoped would be able to connect to this and drive it in real time, but I need the parts from this, so you will not see any more of this orrery.

0:00 Intro
0:43 Timelapse of one full rotation
1:11 Top view
1:39 Detail of gearing
2:37 Outro