| 摘要 |
PURPOSE:To shift natural vibration modes whose directions on a cover shell are different between each other and suppress vibration by forming the cup- shaped cover shell of an enclosed case with plural ridge lines having specific forms and curved faces connecting the parts between said ridge lines. CONSTITUTION:Since vibration which is generated due to the compression of a refrigerant and the like in a cylinder 7 is transmitted to an enclosed case 11 via a bearing 8, etc., the enclosed case 11 is vibrated generating noise. In this case, plural ridge lines 11br having small-curvature R forms are provided on a front cover shell 11b which forms the enclosed case 11 from the center part toward an opening part, the parts between the ridge lines 11br are connected by curved faces 11bh having larger curvatures, and the relative positions of the ridge lines 11br are placed between the arms 8a of the bearing 8. Thereby, the natural frequencies of natural vibration modes which deformingly vibrate in the axial direction and the axial and perpendicular directions of the front cover shell 11b can be shifted between each other, suppressing deformation and vibration in the radial direction. |
