Shift fork lubricating system for transmission

In a transmission of the type including a plurality of shiftable gears each having a circumferential groove, a shift fork shaft having a hollow interior, a plurality of shift forks, each said shift fork having a leading end with a forked pawl portion engaged in one said circumferential groove of one of said shiftable gears and a bearing portion fitted on said shift fork shaft for supporting the respective shift forks, at least one said shift fork being slidable axially along said shift fork shaft, and sliding control means for moving said at least one shift fork along said shift fork shaft for shifting one of said shiftable gears, said shift fork shaft having an outer circumference, each said bearing portion having an inner circumference and a center area of said inner circumference, each of said forked pawl portion having an end face and side surfaces,

• a shift fork lubricating system which is characterized in that said bearing portions of said at least one slidable shift forks have their said inner circumferences formed at their said center areas with annular oil grooves which are axially elongated in the direction of sliding of said shift forks along said shift fork shaft and which are always respectively maintained in communication with said hollow interior of said shift fork shaft by corresponding oil ports opened into said outer circumference of said shift fork shaft, said slidable shift forks having their said bearing portion inner circumferences each also formed at both ends, respectively, of said annular oil grooves with sliding faces of substantially equal axial length which are slidable on said shift fork shaft and which define the respective ends of said annular oil grooves, said shift forks each being formed with oil passages therein having one end opening into said forked pawl portions thereof at locations eccentric to end face thereof rotationally entered by said shiftable gears, said oil passages being in communication at their other ends with said annular oil grooves in said bearing portions, said annular oil grooves enclosing said oil ports in said shift fork shaft.