| 摘要 |
<p>A continuously variable transmission (CVT) (10) operable in a plurality of regimes is described. It comprises a ratio-varying unit ('variator') (11), an epicyclic unit (12, 13), a plurality of ratio combinations, a plurality of regime engaging couplers (C, L, M, H, F, R), a clutch (60) and a drive output shaft (25). The epicyclic unit includes a splitting epicyclic gear (12) and the CVT (10) being arranged such that: a) two components of the splitter epicyclic gear (12) are connected to opposite ends of the variator (11); b) the epicyclic unit (12, 13) has a plurality of outputs connectable in a plurality of different ways to the drive output shaft (25) by way of the plurality of ratio combinations and the plurality of regime engaging couplers (C, L, M, H, F, R) in order to provide the plurality of regimes, and c) the clutch (60) is engageable on starting from rest to provide speeds from zero upwards. The epicyclic unit may also include a recirculating epicyclic gear (13) with the CVT (10) being further arranged such that: a) the saidtwo components of the splitter epicyclic gear (12) are commoned with two components of the recirculating epicyclic gear (13); b) the epicyclic unit (12, 13) and variator (11) ratios are chosen so that at a predetermined variator ratio the epicyclic unit (12, 13) rotates as one whereby alternate regime changes occur at the predetermined variator ratio; c) the recirculating epicyclic gear (13) provides an additionnal output from the epicyclic unit (12, 13) which is connectable to the output shaft (25) to provide one or more creep regimes with speed ranges including zero, and d) the clutch (60) may be (i) locked when starting from rest with one of the creep regimes operative or (ii) gradually engaged when starting from rest with a non-creep regime operative in order to by-pass the creep regime(s).</p> |
