| 摘要 |
PROBLEM TO BE SOLVED: To prevent heat curing due to abrasion and frictional heating of a cushion member by improving lubrication condition between the cushion member of a chain guide and a timing chain. SOLUTION: A semicircular shaped thrust projection 43, which projects on the side of a sprocket flange 41 of an intake/outlet cam axis 32 and abuts to the upper half of a thrust surface 41a of the sprocket flange 41, and is provided on an end surface 36a of a cam bearing 36. A notch portion 51 is provided on the thrust projection 43 in the middle portion of the circumferential direction, while a chain guide 56 is formed with its inner surface 59a standing aslope toward a chain slide portion 60 from near the thrust projection 43. With this configuration, oil gushing from the end surface 36a of the cam bearing 36 is supplied into a cushion member 61 attached to the bottom surface of the cushion slide portion 60. Then, lubrication between the cushion member 61 and a second timing chain 18 is done satisfactorily, and therefore abrasion therebetween is reduced and heat curing due to abrasion and frictional heating of the cushion member 61 is prevented.
|
