| 摘要 |
A casing comprises a casing body (1), a lid (3) fastened to the casing body by means of screws (9) which pass through the lid with clearance via screw passages (7), and an O-ring (6) interposed between said body and lid. Some screw passages (7) open out within the perimeter defined by the O-ring and into cavities (8) which are made in the lid and which permanently communicate with the interior of the casing. When the heads (10) of the screws in these passages do not contact the lid, fluid communication of the interior of the casing with the outside of the casing is effected by the passages. One application of the present invention is the production of a simple and economical hydraulic motor and the invention alleviates the necessity of a separate bleed screw. <IMAGE> |
