| 摘要 |
PROBLEM TO BE SOLVED: To provide a relief valve structure capable of controlling/switching the discharge pressure and the flow rate of oil within the individual low/medium/high rotation number regions of an engine properly in the individual optimum states, and making the structure extremely simple.SOLUTION: A relief valve structure comprises: a valve body B including discharge openings at a large diameter cylindrical part 4, a small diameter head 5 and a rear end side, and a communication hole 62 for communicating an in-valve passage 61 and the outside of the small diameter head 5; a valve housing A1 having a valve element passage 11, a first relief discharge hole 2 and a second relief discharge hole 3 formed therein; and an elastic member 7 for biasing the valve body B toward the side of a relief passage 12 of a valve element passage 11. In a low rotation range of the engine, the small diameter head part holds the relief passage 12 in a closed state; in an intermediate rotation area, the valve body B moves so that the small diameter valve head 5 leaves the relief passage to open the relief passage 12 thereby to provide the communication between the in-valve passage 61 and the first relief discharge hole 2; and, in a high rotation area, the large diameter cylindrical part 4 brings the second relief discharge hole 3 into the open state. |
