| 摘要 |
PROBLEM TO BE SOLVED: To achieve appropriate damping effect regardless of a temperature of operating oil, without increase in size of a device or increase in number of parts. SOLUTION: Hydraulic damping structure of a variable valve train includes: a piston 13 connected with a valve 12; a control chamber 23 having a piston insertion hole 22 in which the piston 13 is slidably inserted; and a hydraulic control mechanism 14 controlling valve open timing or valve close timing of the valve 12, by controlling introduction and discharge of the operating oil into/from the control chamber 23. In the hydraulic damping structure, a cutout 26 is disposed to a corner part of a distal end of the piston 13, and a damping chamber 27, in which the distal end of the piston 13 enters, is formed in the control chamber 23. By making the distal end of the piston 13 enter into the damping chamber 27 along with lift of the valve 12, the operating oil is discharged from the damping chamber 27 through a clearance between the cutout 26 and the damping chamber 27 and the valve 12 is damped. The piston 13 is made from material higher in linear expansion coefficient than material constituting the control chamber 23 and the damping chamber 27. COPYRIGHT: (C)2011,JPO&INPIT |
