Connection structure of oil passage

摘要

A large diameter part is formed in a case-side oil passage, an O-ring is fitted into the large diameter part, and an oil pump is installed to the transmission case by adjusting a discharge hole thereof and the case-side oil passage in alignment with each other. A notch is formed in radial direction from an inner peripheral surface of the large diameter part to an outer peripheral surface of a seat part. When the discharge hole and the case-side oil passage are communicated without the O-ring in the large diameter part, an oil passing through the discharge hole leaks from the notch. Thus in a state the O-ring is not assembled, an oil pressure is not increased by positively leaking the oil through the notch, whereby it can be easily detected that the O-ring is not assembled by mistake.