Power transmission device

Claim 1

A power transmission device comprising: a casing with means for connection to an output member; a driving shaft with means for connection to an input member and coaxially disposed within said casing so as to be relatively rotated with said casing; a driving gear disposed within said casing and coaxially fixed to said driving shaft; at least two driven gears rotatably supported by said casing and engaged with said driving gear within said casing; at least two fluid inlet chambers and at least two fluid outlet chambers formed within said casing with said driving gear and with said at least two driven gears within said casing; a fluid storage chamber formed within said casing; a fluid inlet passage and a fluid outlet passage of which one ends are communicated with said at least two fluid inlet chambers and said at least two fluid outlet chambers, respectively and the other ends thereof being communicated with said fluid storage chamber; and a discharged fluid control device disposed in said fluid outlet passage, said discharged fluid control device being provided with a valve means which closes said fluid outlet passage at a rotative speed of said casing under a predetermined speed and opens said fluid outlet passage at a rotative speed of said casing above the predetermined speed; a non-return device disposed in an opening portion of said fluid inlet passage into said fluid storage chamber for preventing the fluid from flowing out of said fluid inlet passage reversely, said non-return device including centrifugal force-activated means for substantially instantaneously opening and closing said fluid inlet passage in dependence upon whether said casing is rotating faster or slower than a predetermined speed.