Residual magnetic devices and methods

1. A clutch for use in coupling a first element to a second element, the clutch comprising:

a core housing coupled to one of the first element and the second element;

an armature positioned adjacent to the core housing, the armature coupled to one of the first element and the second element; and

a coil positioned in the core housing, the coil receiving a magnetization current to create a substantially closed magnetic path including an air gap from approximately 0.002 inches to approximately 0.005 inches between the core housing and the armature in order to create an irreversible residual magnetic force with a magnetic air gap energy of at least 6652 (line-amp-turn)/cm 3 and to couple the first element to the second element in the subsequent absence of the magnetization current and in the absence of any other magnetic force.

2. The clutch of claim 1 further comprising a controller to provide the coil with the magnetization current to create the irreversible residual magnetic force between the armature and the core housing.

3. The clutch of claim 1 wherein magnetic domains become misaligned in at least one of the armature and the core housing in order to null the irreversible residual magnetic force by at least one of a controller providing a demagnetization current to the coil and a release mechanism increasing an air gap between the armature and the core housing.

4. The clutch of claim 3 wherein the controller restores the irreversible residual magnetic force by providing the magnetization current again to the coil.

5. The clutch of claim 1 wherein the irreversible residual magnetic force substantially prevents a shear force from causing movement between the armature and the core housing.

6. The clutch of claim 1 wherein the irreversible residual magnetic force allows rotational movement of the first element.

7. The clutch of claim 6 wherein the irreversible residual magnetic force allows translational movement of the first element.

8. The clutch of claim 1 wherein the irreversible residual magnetic force allows translational movement of the first element.

9. The clutch of claim 1 wherein a first cross-sectional area of an inner core of the core housing is substantially equal to a second cross-sectional area of an outer core of the core housing, which is substantially equal to a third cross-sectional area of the armature, which is substantially equal to a fourth cross-sectional area of a yoke of the core housing.

10. The clutch of claim 1 wherein at least one of the armature and the core housing are constructed of at least one of SAE 1002 steel, SAE 1018 steel, SAE 1044 steel, SAE 1060 steel, SAE 1075 steel, and SAE 52100 steel.

11. The clutch of claim 1 wherein at least one of the armature and the core housing are constructed of chromium steel.

12. The clutch of claim 1 wherein a controller determines whether the irreversible residual magnetic force is present between the core housing and the armature.

13. The clutch of claim 1 wherein substantially all portions of the core housing and the armature magnetically saturate at substantially the same time.

14. The clutch of claim 1 wherein a demagnetization current is a substantially constant value due to the core housing and the armature being magnetically saturated when the irreversible residual magnetic force is created.

15. A clutch for use in coupling a first element to a second element, the clutch comprising:

electromagnetic assembly means coupled to the first element and the second element; and

controller means for providing a magnetization current to the electromagnetic assembly means to create a substantially closed magnetic path including an air gap from approximately 0.002 inches to approximately 0.005 inches in order to create an irreversible residual magnetic force with a magnetic air gap energy of at least 6652 (line-amp-turn)/cm 3 and to couple the first element to the second element in a subsequent absence of the magnetization current and in the absence of any other magnetic force.

16. The clutch of claim 15 wherein the controller means provides a demagnetization current to the electromagnetic assembly means to null the irreversible residual magnetic force in order to allow the first element to move with respect to the second element.

17. The clutch of claim 15 and further comprising separation means for physically increasing an air gap between the armature and the core housing and substantially nulling the irreversible residual magnetic force.

18. The clutch of claim 15 and further comprising means for misaligning magnetic domains in the electromagnetic assembly means in order to null the irreversible residual magnetic force.

19. The brake of claim 18 wherein the controller means restores the irreversible residual magnetic force in the electromagnetic assembly means by providing the magnetization current again.