Fan blades having variable pitch compliantly responsive to a linear actuator
A variable pitch fan blade mechanism, particularly well suited for automotive applications, wherein the blade pitch is compliantly responsive to selective actuation of a linear actuator. A linear actuator is disposed in the fan shaft composed of an electric drive component drivingly engaged with a follower component, a set of fan blades resiliently attached to a head of the follower component, and a push assembly connected to the fan shaft composed of a push plate and a plurality of push rods, one push rod for each fan blade. Each push rod engages its respective fan blade adjacent an edge thereof. The fan blades are resiliently biased toward the push rods such that axial movement of the push rods in response to actuation of the linear actuator results in compliant changes of pitch of the blades.
1. A variable pitch fan blade mechanism, comprising:
a fan shaft having a proximal end portion;
a linear actuator connected with said fan shaft at said proximal end thereof, said linear actuator comprising a drive component seated in said fan shaft and a follower component slidably movable axially with respect to said fan shaft responsive to actuation of said linear actuator;
a plurality of push rods connected to said fan shaft; and
a plurality of fan blades connected to said follower component, each push rod abutting a respective fan blade, wherein each fan blade is resiliently biased toward its respective push rod;
wherein actuation of said linear actuator results in said follower component moving in relation to said fan shaft such that each said fan blade moves in relation to its respective push rod such that a blade pitch of each said fan blade is compliantly changed with respect to a blade rotation plane.
2. The variable pitch fan blade mechanism of claim 1 , wherein:
said drive component further comprises:
a motor receptacle formed in said proximal end portion of said fan shaft;
an electric motor non-rotatably seated in said motor receptacle, said electric motor having a threaded motor shaft; and
a follower receptacle formed in said fan shaft in communicating relation to said motor receptacle, said follower receptacle having a splined sidewall; and
said follower component further comprises:
a splined pedestal meshed with said splined sidewall so that said pedestal is non-rotatably slidable axially with respect to said fan shaft, said pedestal having a threaded bore into which said threaded motor shaft is threaded, wherein actuation of said motor causes said follower to axially slide in said follower receptacle; and
a head connected to said pedestal, wherein said fan blades are connected to said head.
3. The variable pitch fan blade mechanism of claim 2 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.
4. The variable pitch fan blade mechanism of claim 2 , further comprising:
a plurality of torsion bars, each torsion bar connecting an inside end of a respective fan blade to said head, wherein each torsion bar has a torsional bias which resiliently biases its respective fan blade abuttingly toward its respective push rod; and
wherein each push rod abuts its respective fan blade adjacent an edge thereof so as to establish a torque moment with respect to the push rod.
5. The variable pitch fan blade mechanism of claim 4 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.
6. The variable pitch fan blade mechanism of claim 4 , wherein each said torsion bar is connected to said head in tangential relation thereto.
7. The variable pitch fan blade mechanism of claim 6 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.
8. A fan assembly comprising at least one fan, wherein each fan comprises:
a fan shaft having a proximal end portion;
a plurality of fan blades rotatively driven by said fan shaft; and
a variable pitch fan blade mechanism, comprising:
a linear actuator connected with said fan shaft at said proximal end thereof, said linear actuator comprising a drive component seated in said fan shaft and a follower component slidably movable axially with respect to said fan shaft responsive to actuation of said linear actuator; and
a plurality of push rods connected to said fan shaft, wherein said plurality of fan blades are connected to said follower component, each push rod abutting a respective fan blade, wherein each fan blade is resiliently biased toward its respective push rod;
wherein actuation of said linear actuator results in said follower component moving in relation to said fan shaft such that each said fan blade moves in relation to its respective push rod such that a blade pitch of each said fan blade is compliantly changed with respect to a blade rotation plane.
9. The fan assembly of claim 8 , wherein:
said drive component further comprises:
a motor receptacle formed in said proximal end portion of said fan shaft;
an electric motor non-rotatably seated in said motor receptacle, said electric motor having a threaded motor shaft; and
a follower receptacle formed in said fan shaft in communicating relation to sad motor receptacle, said follower receptacle having a splined sidewall; and
said follower component further comprises:
a splined pedestal meshed with said splined sidewall so that said pedestal is non-rotatably slidable axially with respect to said fan shaft, said pedestal having a threaded bore into which said threaded motor shaft is threaded, wherein actuation of said motor causes said follower to axially slide in said follower receptacle; and
a head connected to said pedestal, wherein said fan blades are connected to said head.
10. The fan assembly of claim 9 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.
11. The fan assembly of claim 9 , further comprising:
a plurality of torsion bars, each torsion bar connecting an inside end of a respective fan blade to said head, wherein each torsion bar has a torsional bias which resiliently biases its respective fan blade abuttingly toward its respective push rod; and
wherein each push rod abuts its respective fan blade adjacent an edge thereof so as to establish a torque moment with respect to the push rod.
12. The fan assembly of claim 11 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.
13. The fan assembly of claim 11 , wherein each said torsion bar is connected to said head in tangential relation thereto.
14. The fan assembly of claim 13 , further comprising:
a push plate connected to said proximal end portion of said fan shaft, wherein said push rods are connected to said push plate in upstanding relation thereto.