The invention relates to the 
assembly of a unidirectional bearing, which comprises a unidirectional bearing semiautomatic roller loading 
machine capable of automatically conducting suction, delivery, feeding, discharging and loading of rollers and rotation of a holder at an angle. Two round pneumatic roller storage disks capable of automatically orienting and delivering rollers are arranged inside a workpiece basket positioned on one side of a rectangular 
workbench, a rectangular vertical controller is arranged on the other side of the rectangular 
workbench, a PLC 
chip is equipped inside the controller for controlling the operation of the unidirectional bearing semiautomatic roller loading 
machine by 
programming the PLC 
chip, two completely same holder mechanisms are arranged at the front end of the rectangular 
workbench for manually placing a holder into a serrated holder seat; two completely same transposition mechanisms are arranged below the holder mechanisms for controlling the powering on sequence of five solenoid valves via the PLC in the controller, so as to press the rollers in the roller storage disks into a material guide 
pipe and wait for the action of a rolling pushing 
machine; and when the rolling pushing machine pushes a first roller into a pocket hole of the holder, the transposition mechanisms start to operate by the steps of rotating an angle in accordance with a predetermined angle, waiting for the pushing of a second roller, and repeating and stopping until the pocket hole of the holder is full of rollers, and then the holder is removed and a holder not filled with rollers is loaded to start the next round roller loading operation by pressing a 
loop start button on a controller panel. The inventive 
assembly has the advantages of easy 
assembly of the unidirectional bearing and high assembly efficiency.