Hypotrochoidal planetary gear speed changers

摘要

Each of several types of speed changers comprise a pair of generally dish-shaped housing sections releasably secured in confronting relation around their peripheries with a high speed shaft journaled in an axial bore of one section, and a low speed shaft or hub journaled in the other section coaxially of the high speed shaft. At least one two-step cluster gear is secured to the inner end of the high speed shaft and has a pinion section drivingly engaged with a set (three) of two-step planetary cluster gears that are rotatably mounted on three shafts that are fixed at opposite ends in a pair of circular carrier plates which also are journaled coaxially in the housing sections to be rotatable therein in unison. The pinion sections of the planetary cluster gears are drivingly engaged with the teeth of an internal sun gear secured in the housing coaxially thereof. A feature of the invention is that merely by adding additional sets of driving and planetary cluster gears to a unit, all which gears may be similar in construction, various ratios of speed change can be achieved inexpensively.