Electric shift transfer case
AssigneeBorgWarner Inc.
InventorsGary Oliveira, Fredric Tubbs
Life of this patent
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Abstract
A shift fork restrictor operably disposed in a transfer case for the purpose of allowing the shift motor to transfer energy to the currently existing double wound spring, where the energy is stored until the shift motor sensor indicates that the motor is in the proper range location. When the motor is in the proper range location, the stored energy in the spring is released by the shift fork restrictor releasing the cam allowing for maximum torque and speed to be provided through the secondary rail, cam, and shift fork to complete the requested range shift. This configuration can be used to, among other things, select a high or low range in the transfer case, as well as couple the input and output shafts together, which have different gear ratios.
Claims20
A shift mechanism for a transfer case comprising:
- a drive member having a bi-directionally rotating output;
- a rotatable helical cam;
- a shift fork having a cam follower operably associated with said helical cam;
- an energy storing spring operably disposed between said rotating output of said drive assembly and said cam;
- and
- a two-position solenoid, for selectively inhibiting and allowing motion of said rotatable helical cam.
A method for performing a synchronized electronic shift in a two-speed transfer case, having an input shaft, and an output shaft, comprising the steps of:
- providing for restriction of movement of a rotatable helical cam through the use of a solenoid;
- providing for the use of a shift fork possessing a cam follower that is received by said rotatable helical cam;
- providing for a drive member having a bi-directional rotating output;
- providing for the storing of energy through the use of a spring assembly, which is operably disposed between and couples said drive member and said helical cam, and;
- providing for two sensors that can detect the position of said shift fork.
A method of storing energy to be used for performing high-speed shifts in a transfer case comprising the steps of:
- storing energy in a spring assembly, and;
- selectively restricting the motion of a helical cam by use of a solenoid, upon release of which performs requested shift.
Dependencies are inferred from the claim text.