| 摘要 |
A hydraulic servo cylinder, particularly for hydraulic steering assistance in motor vehicles, has two pistons (4; 5) each provided with a seal (15; 14) between the piston and the inner cylinder wall. The cylinder (3), which simultaneously forms the steering casing, has an enlarged diameter (12; 13) over at least part of its circumference at its inner wall in the zone of maximum stroke of each piston (end position). This enlarged diameter provides a gap between the seal and inner wall of the cylinder adjacent a low pressure chamber (8) arranged behind the piston when the piston is moved into the enlarged diameter. Each seal (15; 14) has a sealing portion (19) extending radially outwards and consisting of an elastic material, and a base portion (20) arranged axially in the piston (4; 5). A ring (21) of rigid material is located over the base portion (20) with little play in the diameter. <IMAGE> |
