side low pressure oil discharge hole 119 y then the oil flows through the oil passage l 1 extending rearwardly and moves toward the oil cooler 139 and the low pressure oil filter 140 the oil that has cooled by the oil cooler and is purified by the low pressure oil filter and passes through the outflow oil passage l 2 communicating with an oil outflow pipe 140 a placed at the center portion of the low pressure oil filter moves to the right in fig1 via the oil passage l 3 the oil in the high pressure discharge passages 121 x 121 z of the high pressure oil pump 90 h interflows and is discharged from the right side high pressure oil discharge hole 125 w to enter the high pressure oil filter 141 for purification then the purified oil flows out from the outflow oil passage h 1 communicating with the center portion of the high pressure oil filter and moves rearwardly through the oil passage h 2 in addition on the midway the purified oil changes its direction to the right in fig1 through the passage h 3 and moves upwardly through a passage not shown and is used to lubricate the static hydraulic type continuously variable transmission 55 fig1 depicts the horizontal cross section of the oil pump assembly 90 the water pump 143 and an oil passage subsequent to the oil passage l 3 of the low pressure oil pump as viewed from above the oil passage l 3 of the low pressure oil pump shown in fig1 further extends to the right and connects with an oil passage l 4 at the midway thereof and then the oil passage l 4 extends forwardly the oil passage l 4 connects at its end.