| 摘要 |
PURPOSE:To lower the noise produced by an engine, by forming a plurality of bearing supporting partition walls side by side at a lower portion of the cylinder, constituting a bearing beam by connecting lower partition walls mating respectively to the upper partition walls to each other at the bottom thereof, and thereby increasing the flexural rigidity of the cylinder block. CONSTITUTION:A cylinder block 10 is formed with bearing supporting partition walls 11a in the manner that they are integral with the cylinder block 10 and located between cylinders. Further, lower bearing supporting partition walls 11b mating respectively to the upper bearing supporting partition walls 11a are provided for supporting crank shaft bearings. These partition walls 11a, 11b are divided at the center of bearings and shaped as a whole in a trapezoidal form that is enlarged toward its bottom. Further, a bearing beam 12 extending in parallel with the axis of the crank shart is fixed integrally to the bottom of partition walls 11b. The bearing beam 12 is shaped to have a width W1 equal to the width of partition walls 11b at the bottom thereof and fixed to the partition walls 11a by bolts 13. With such an arrangement, it is enabled to increase the flexural rigidity of cylinder block 10 in both of vertical and horizontal directions. |
