Oil filter incorporating a drain valve

摘要

An oil filter includes a housing having a case and a cap detachably engaged with each other and a filter element detachably contained in the housing. An oil-draining hole is provided at a bottom portion of the case. The oil filter further includes a plug member for opening and closing the draining oil hole and a spring member for operating the plug member according to an engagement state of the case and the cap. At an intermediate condition of the engagement state of the case and the cap, the plug member moves to the cap side to open the oil-draining hole. Therefore, before changing the filter element, oil staying in the oil filter can be readily securely discharged to the outside.