| 摘要 |
The present invention relates to an actuator for turning a shaft (11) to a limited degree, e.g. the shaft of a butterfly valve or the like, the actuator comprising a housing (2) having a cylindrical chamber (6), inlets and outlets (7, 8) for a pressure fluid to the cylindrical chamber, a piston (9) in the cylindrical chamber, which can be displaced in the cylindrical chamber by means of a pressure fluid and is provided with a rack (10) with a toothed segment ( 27) cooperating with a gear ring segment (22), fixedly mounted on said shaft (11), which extends right through the cylindrical chamber (6) and through the wall of the housing (2). The characteristic feature of the invention is that the toothed segment (27) is disposed at the bottom of a groove (26) in the rack (10), that said gear ring segment (22) has a breadth in the axial direction, which corresponds to the breadth of said groove, and that said gear ring segment is provided in the groove (26) to mesh with the toothed segment, the shaft (11) in this way being fixed in the axial direction in the housing (2). <IMAGE> |
