Speed-switchable reduction gear

A speed-switchable reduction gear comprising:

• an input shaft;
• an output shaft which outputs a rotational driving force transmitted from the input shaft, to an outside;
• a plurality of output-side geared-wheels which are mounted on the output shaft correspondingly to respective reduction ratios, each of the reduction ratios being a ratio of a rotating speed of the input shaft to a rotating speed of the output shaft, so as to be capable of transmitting the rotational driving force from the input shaft to the output shaft and switching the reduction ratios;
• a shifter which selectively connects one of the plurality of output-side geared-wheels to the output shaft to allow the rotational driving force to be transmitted from the output-side geared-wheels to the output shaft;
• a plurality of bearing pairs which are provided to each of the plurality of output-side geared-wheels, respectively, the bearing pairs including respective first bearings and respective second bearings and formed with respective cells, the first bearing and the second bearing in each of the bearing pairs being disposed on an outer peripheral surface of the output shaft and spaced in an axial direction of the output shaft so as to form the cell between the first bearing and the second bearing for supplying lubricating oil to the first bearing and the second bearing, the first bearings and the second bearings supporting the output-side geared-wheels, respectively, so as to allow the output-side geared-wheels to be rotated relatively to the output shaft;
• and
• a plurality of dividing walls each provided in each of the cells on an inner side of each of the plurality of output-side geared-wheels so as to protrude radially outward from the outer peripheral surface of the output shaft, wherein:
• each of the first bearings is a shifter-side bearing provided at a position where each of the first bearings allows the lubricating oil to be supplied to the shifter through each of the first bearings, the position being closer to the shifter than each of the dividing walls, and each of the second bearings is a non-shifter-side bearing positioned on opposite side of each of the dividing walls to each of the first bearings;
• the output shaft includes an axial lubricating-oil flow path, which extends along axially of the output shaft in the output shaft to allow the lubricating oil to flow in the axial lubricating-oil flow path, and a plurality of supply flow paths which extend radially outward from the axial lubricating-oil flow path to make communication with the cells;
• and
• the dividing walls divide the cells into a plurality of first cell portions adjacent to the first bearings and a plurality of second cell portions adjacent to the second bearings, respectively, and allows the lubricating oil to be supplied from the supply flow paths into the first cell portions and to be supplied from the supply flow paths into the second cell portions so as to make pressure of the lubricating oil in the first cell portions be higher than pressure of the lubricating oil in the second cell portions.