| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable the automatic gear change of a second transmission, in a power transmission device comprising the second transmission which is interposed between a stepped first transmission and has an engaging clutch.SOLUTION: A power transmission device comprises a second transmission 40 having a planetary gear mechanism 45 in which a ring gear 47 and a planetary carrier 49 are connected to an output shaft 27 of a first transmission 25 and drive wheels, a dog clutch 50 which performs the connection and release of the ring gear 47 and the planetary carrier 49, and a two-way clutch 52 interposed between a sun gear 46 of the planetary gear mechanism 45 and a transmission case 22. The two-way clutch 52 regulates the rotation of the sun gear 46 in a direction opposite to the ring gear 47 at forward traveling. When the dog clutch 50 is released, and a pedal-in amount of an accelerator pedal is reduced, the second transmission 40 is gear-changed by being engaged with the dog clutch 50 accompanied by a decrease of a rotation number of the ring gear 47 and an increase of a rotation number of the sun gear 46.</p> |
