摘要:
A flextensional transducer (1 ) that can be stored at room temperature and activated and operated at an elevated temperature in excess of 200°C, comprises (i)an elongate driver (2), (ii)a flextensional housing shell (3) containing the elongate driver, comprising a pair of contact portions (4) located on opposite sides of the housing shell and in mechanical contact with the ends of the driver, and having a different coefficient of thermal expansion from that of the driver, and (iii)thermal compensating members (29); the flextensional housing shell moving by flexing on actuation, the thermal compensating members being located in, or on, parts (17) of the housing shell that move on actuation, and comprising a material having a different coefficient of thermal expansion from that of surrounding parts of the housing shell, such that as the temperature increases up to the said elevated temperature the thermal compensating members expand more or less than the said surrounding parts of the housing shell, causing the housing shell to flex so as to urge the contact portions (4) of the housing shell towards each other to compensate for the greater thermal expansion of the housing relative to that of the driver member (2).
摘要:
A flextensional transducer (1 ) that can be stored at room temperature and activated and operated at an elevated temperature in excess of 200°C, comprises (i)an elongate driver (2), (ii)a flextensional housing shell (3) containing the elongate driver, comprising a pair of contact portions (4) located on opposite sides of the housing shell and in mechanical contact with the ends of the driver, and having a different coefficient of thermal expansion from that of the driver, and (iii)thermal compensating members (29); the flextensional housing shell moving by flexing on actuation, the thermal compensating members being located in, or on, parts (17) of the housing shell that move on actuation, and comprising a material having a different coefficient of thermal expansion from that of surrounding parts of the housing shell, such that as the temperature increases up to the said elevated temperature the thermal compensating members expand more or less than the said surrounding parts of the housing shell, causing the housing shell to flex so as to urge the contact portions (4) of the housing shell towards each other to compensate for the greater thermal expansion of the housing relative to that of the driver member (2).
摘要:
A multistage flextensional transducer comprises at least one inner elongate driver member (202) within and mechanically coupled to an inner shell (203) that is nested within an outer shell (208); the inner shell comprising a pair of contact portions (204) abutting the driver member and a pair of transmission portions (211) on opposite sides of the inner shell between the contact portions; the outer shell being arranged so that the transmission portions act as bridging driver members between the said inner and outer shells. Flexure of the outer shell being driven, on actuation of the transducer, by movement of the bridging driver members results in amplified motion of transmission members (61). The transducer may act as a push or pull actuator or sensor, may magnify displacement and may employ smart materials as driver members. Also cylindrical modules containing thin flextensional actuators may provide axial displacement in a downhole environment and may move a device axially along a downhole pipe or close a valve opening or inch along the pipe.