摘要:
A transmission fluid circuit includes a transmission, a cooler, and a valve. The valve includes a housing, a spool and an actuator. The spool is movable inside the housing between a first position and a second position. The actuator includes a smart material configured to be activated in response to the temperature of the fluid exhibiting at least a first temperature such that the actuator is in a first state. The smart material is configured to be deactivated in response to the fluid being a sufficient number of degrees less than the first temperature such that the actuator is in a second state. The fluid flows from the housing to the transmission and from the transmission the cavity when the spool is in the first position. The fluid flows from the housing to the cooler and from the cooler to the transmission when the spool is in the second position.
摘要:
A method of controlling a shape memory alloy actuator utilizing the change in resistance exhibited by the actuator over an actuation cycle, or a derivative thereof, to identify at least one event, such as, for example, a peak, valley, change in slope without reaching a valley, or a jump in resistance within the signal plot that corresponds to the start of actuation, end of actuation, an overload case, and the introduction of a resistive element respectively, and generating a response based upon the event.
摘要:
A method of sensing an ambient heat transfer condition surrounding a shape memory alloy element includes heating the shape memory alloy element, sensing the resistance of the shape memory alloy element, and measuring the period of time taken to heat the shape memory alloy element to a pre-determined level of a resistance characteristic. The ambient heat transfer condition surrounding the shape memory alloy element is calculated by referencing a relationship between the period of time taken to heat the shape memory alloy to the pre-determined level of the resistance characteristic and the ambient heat transfer condition.
摘要:
A method for controlling welding forces of a weld tip to a work piece during a vibration-welding process includes positioning an Active Material (AM) element adjacently to a welding interface, and varying a property of the AM element to regulate the welding force. The AM element may be disposed between the weld tip and a weld face thereof, or between the work piece and an anvil. The property may be varied as a function of heat generated by the welding process. A property of each of a plurality of AM elements may be independently and selectively varied via an energy source, or passively. A vibration welding system includes a weld tip and an AM element connected adjacently to a welding interface. The system regulates a welding force applied by the weld tip to a work piece during the welding process by varying a property of the AM element.
摘要:
Active material actuator assemblies are provided that enable simplified control systems and faster actuator cycle times. A movable member is provided that has multiple active material components operatively connected to it. The active material components are separately selectively activatable for moving the movable member. Movement of the movable member via activation of a first of the active material components triggers activation of the second active material component to further move the movable member. Alternatively or in addition, previously activated active material components are protected from undesired stretching during activation of another active material component or, when desired, an active material component may be reset via activation of another of the active material components in order to prepare it for subsequent activation.
摘要:
A method of reducing an initial stress on a cable includes stretching the cable to a first length to thereby define the initial stress. The cable has a central longitudinal axis, and includes a plurality of wires each twisted around the axis and formed from a shape memory alloy transitionable in response to a signal between a first state wherein each of the wires has a first temperature-dependent length, and a second state wherein each of the wires has a second temperature-dependent length that is less than the first. After stretching, the method includes activating the alloy by exposing the alloy to the signal such that the alloy transitions from the first to the second temperature-dependent state. Concurrent to activating, the method includes elongating the cable to a second length that is greater than the first to define a second stress on the cable that is less than the first.
摘要:
In an embodiment, a device comprises an active material. Activation of the active material causes deformation within the device to conform to and/or retain an object without engaging the object below a surface of the object. In another embodiment, contact with an object causes deformation within the device to conform to and/or retain the object. In yet another embodiment, an object holder can comprise: a recess, a cover disposed over the recess, and a switch configured to cause the active material to retain a deformed shape in the recess. The cover comprises an active material. The active material is configured to deform into the recess when contacted with an object.
摘要:
A method of adaptively assembling first and second workpieces utilizing shape memory polymer activation to facilitate alignment and retention, wherein the workpieces present and the method employs at least one active nub and/or mated receptacle, and the modulus shifting and shape memorization capabilities of shape memory polymer are alternatively used to further engage the nub and receptacle during assembly.
摘要:
A heat engine includes a first rotatable pulley and a second rotatable pulley spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes a first wire, a second wire, and a matrix joining the first wire and the second wire. The first wire and the second wire are in contact with the pulleys, but the matrix is not in contact with the pulleys. A timing cable is disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.