Thermal isolator for actuator and valve assembly
An exhaust valve assembly includes a valve body, a valve supported by a shaft within the valve body, and an actuator that drives the shaft to move the valve relative to the valve body. A thermal isolator is associated with the shaft to reduce heat transfer from the valve to the actuator.
1 . An exhaust valve assembly comprising:
a valve body;
a valve supported for movement within said valve body;
an actuator that varies a position of said valve within said valve body to control exhaust flow; and
a thermal isolator associated with said valve to reduce heat transfer from said valve to said actuator.
2 . The exhaust valve assembly according to claim 1 including a shaft that supports said valve with said actuator driving said shaft to control the position of the valve within the valve body.
3 . The exhaust valve assembly according to claim 2 wherein said shaft comprises a valve shaft, and including an actuator shaft driven by said actuator wherein said thermal isolator comprises a coupling that couples said actuator shaft to said valve shaft to transfer torque between said actuator and said valve.
4 . The exhaust valve assembly according to claim 3 wherein said coupling comprises a bellows.
5 . The exhaust valve assembly according to claim 4 wherein said bellows comprises a flexible metal bellows.
6 . The exhaust valve assembly according to claim 3 wherein said coupling comprises a rigid connector made from an insulating material.
7 . The exhaust valve assembly according to claim 6 wherein said insulating material comprises one of ceramic and silicon.
8 . The exhaust valve assembly according to claim 6 wherein said valve shaft is made from a metallic material.
9 . The exhaust valve assembly according to claim 6 wherein said rigid connector, said valve shaft, and said actuator shaft are co-axial.
10 . The exhaust valve assembly according to claim 3 wherein said valve shaft is offset from said actuator shaft and wherein said coupling comprises a linkage.
11 . The exhaust valve assembly according to claim 10 wherein said linkage includes at least a first link member coupled to said valve shaft and a second link member coupled to said actuator shaft with said first and second link member cooperating with each other to transfer torque between said actuator and said valve.
12 . The exhaust valve assembly according to claim 3 wherein said coupling comprises a flexible shaft.
13 . The exhaust valve assembly according to claim 2 wherein said actuator comprises an electric actuator.
14 . The exhaust valve assembly according to claim 2 wherein said valve comprises a flapper valve and said valve body comprises an exhaust tube.