| 摘要 |
The diaphragm comprises a peripheral zone (12) and a central zone (16) in the same plane. Between these zones there is a corrugated zone comprising 2n corrugated portions (181 to 184) which are separated by connection zones (201 to 204). Any one corrugated portion may be derived from the adjacent corrugated portion by a rotation through 180 DEG about the connection zone, or else by a rotation of 2 pi /2n about the diaphragm axis followed by a symmetry about the housing plane. |
