Adaptable layshaft type gearbox using a planetary gearset, in particular for automobile vehicles

Abstract

A gearbox comprises parallel primary or input and secondary or output shafts in a casing. An output gear train of two constant-mesh gearwheels is fastened to the secondary shaft. An independent input gear train of four constant-mesh gearwheels and a first and a second clutch are mounted on the primary shaft. A third clutch is mounted on the secondary shaft. The first and third clutches respectively couple the input train to the primary shaft and to the secondary shaft. A three-element planetary gearset concentric with the primary shaft comprises a sun gear fastened to the input train, a planet carrier coupled to the primary shaft by the second clutch and a ring gear fastened to the output train. Thus the gearbox features three gear ratios by respective combinations of pairs of the three clutches. This arrangement constitutes a basic gearbox. More complex gearboxes derived from the basic gearbox comprise a supplementary gear train and a fourth clutch and/or a first brake and/or a second brake for respectively driving and/or immobilizing the sun gear and/or the planet carrier. This provides numerous additional forward and reverse gear ratios that are always well distributed and easy to control.

Dependencies are inferred from the claim text.