| 摘要 |
PURPOSE:To lubricate bearings of crank shaft sufficiently, by feeding lubricating oil flowing over the wall surface and received in wall-surface-oil capturing grooves to crank bearings for other cylinders. CONSTITUTION:At the region where lower wall surface on the side of crank chamber 16 and inner wall surface of brank chamber 16 are connected, there are formed substantially horizontal flat lands 22. At portions of these flat lands 22 near the crank shaft, there are formed wall-surface-oil capturing grooves 23 which are communicated to respective oil passages 24 formed in a metal threaded to crank case 3. Oil passage 24 for a first cylinder is communicated via check valve 25 to oil passage 8a formed in a third bearing 5. With such an arrangement, when pressure in one crank chamber is positive, pressure in other crank chambers becomes negative. Therefore, by the function of this differential pressure, wall-surface oil captured by grooves 23 is fed to crank bearings 4, 5 for other cylinders. |
