Abstract: Disclosed is a clearance control swash plate device for a transmission or reducer and a single-shaft two-speed drive system, including the clearance control swash plate device, with a friction clutch. The clearance control swash plate device includes: an action plate mounted on a power transfer shaft; a first thrust bearing disposed on the action plate, and configured to prevent rotation force, received from the action plate, from being transferred; a first clearance swash plate disposed on the first thrust bearing; a second clearance swash plate disposed on the first clearance swash plate; a worm engaged with a worm gear formed on the outer circumference of the second clearance swash plate; a second thrust bearing disposed on the second clearance swash plate, and configured to prevent rotation force, received from the second clearance swash plate, from being transferred; and a thrust washer disposed on the second thrust bearing.

Abstract: Disclosed herein is a single-shaft two-speed drive system including a synchronizer. The single-shaft two-speed drive system includes: a housing; a motor unit including a stator and a rotor; a first planetary gear set including a first sun gear, a plurality of first planetary gears, a first ring gear, and a first carrier; a second planetary gear set including a fastening cone, an integrating cone, a synchronizer, a second sun gear, a plurality of second planetary gears, a second ring gear, and a second carrier; and a differential; wherein the sleeve is moved in a direction of the fastening cone and coupled to the fastening cone to thus obtain a single gear reduction ratio and the sleeve is moved in a direction of the integrating cone and coupled to the integrating cone to thus obtain driving power without gear reduction.