| 摘要 |
PURPOSE:To prevent mixing of two kinds of oil, by combining an ordinary oil seal with an oil seal with thread grooves which is capable of increasing the suction pressure from the atmosphere side to oil side through utilization of a turning shaft. CONSTITUTION:Thread grooves 39 are formed in the inner peripheral surface of the lip 37a of an oil seal 33 at its tapered part 37b located on an atmosphere side, such that the suction pressure from a back atmospheric side is increased in connection with the direction of rotation of an output shaft 18. By employing such an arrangement, almost all of oil splashed and introduced into a space 34 at the back of oil seals 32, 33 via an air breather 35 is returned through the oil seal 33, so that the amount of oil leaked through the oil seal 32 is reduced substantially to zero. |
