| 摘要 |
PURPOSE:To appropriately hold down the pressure of lubricating oil applied to an oil seal, by defining oil escape passages between a crankshaft and an external gear fitted thereon and connecting the oil escape passages to a crankcase. CONSTITUTION:The front end of the crankshaft 14 projects out of the crankcase 12 through a pump housing 10. The external gear 16 is fitted on the crankshaft 14. An internal gear 20 is eccentrically engaged with the external gear 16. The inside surface of the external gear 16 having a center hole is so cut that the lubricating oil escape passages, which communicate with the crankcase 26 through an annular chamber 26, are formed between the crankshaft 14 and the external gear 16. As a result, the lubricating oil in the annular chamber 26 is allowed to return to the crankcase 12. Therefore, the pressure of the chamber 26 is held down and proper sealing-up is performed by the oil seal 24. |
