Patent ID: 8887871

Claim:
A check valve of a cylinder head, which controls oil supply to the cylinder head in accordance with oil pressure of a hydraulic pump, comprising: a lower cover of cylindrical shape comprising upper and lower surfaces, the upper surface being bored and the lower surface having at least one first oil hole for receiving oil from the hydraulic pump; an upper cover coupled to the upper surface of the lower cover and having a slide axle and at least one second oil hole; a first plate mounted in the lower cover, sliding axially along the slide axle, and having at least one third oil hole that is disposed eccentrically to the at least one second oil hole; and a second plate disposed between the first plate and the lower cover, sliding axially along the slide axle, and having at least one fourth oil hole disposed eccentrically to the first, second, and third oil holes; wherein the at least one first oil hole and the at least one fourth oil hole do not communicate with each other in the case that the second plate is contacted with the lower cover; wherein the at least one fourth oil hole and the at least one third oil hole overlap with each other in an axial direction of the slide axle by as much as a first overlapped portion in the case that the second plate is contacted with the first plate; wherein the second, third, and fourth oil holes overlap in the axial direction of the slide axle with each other by as much as a second overlapped portion in the case that the second plate is contacted with the first plate and the first plate is also contacted with the upper cover, and wherein the first overlapped portion is larger than the second overlapped portion and oil amount supplied to the cylinder head is proportional to the first and second overlapped portions.