Magnetic gears, and related systems and methods
A magnetic gear may comprise a first gear member comprising a plurality of permanent magnets arranged to have a first number of magnetic pole pairs and a second gear member positioned relative to the first gear member. The second gear member may comprise a plurality of individually rotatable magnetized elements each driven and synchronized with one another to selectively generate a second number of magnetic pole pairs that differs from the first number of magnetic pole pairs. The magnetic gear may further comprise a plurality of interpole elements positioned between the first and second gear members. The plurality of interpole elements may be disposed to harmonically couple the magnetic pole pairs of the first gear member with the magnetic pole pairs of the second gear member for each selectively generated second number of magnetic pole pairs.
1. A magnetic gear comprising:
a first gear member comprising a plurality of permanent magnets arranged to have a first number of magnetic pole pairs;
a second gear member positioned relative to the first gear member, the second gear member comprising a plurality of individually rotatable magnetized elements each driven and synchronized with one another to selectively generate a second number of magnetic pole pairs that differs from the first number of magnetic pole pairs; and
a plurality of interpole elements positioned between the first and second gear members, the plurality of interpole elements disposed to harmonically couple the magnetic pole pairs of the first gear member with the magnetic pole pairs of the second gear member for each selectively generated second number of magnetic pole pairs.
2. The device of claim 1 , wherein the first number of magnetic pole pairs is greater than the second number of magnetic pole pairs.
3. The device of claim 1 , wherein the plurality of individually rotatable magnetized elements comprise a plurality of individually rotatable permanent magnets.
4. The device of claim 1 , wherein the plurality of individually rotatable magnetized elements comprise a plurality of individually rotatable magnetized cylinders.
5. The device of claim 1 , wherein the plurality of interpole elements comprise a plurality of free-spinning magnetized elements.
6. The device of claim 5 , wherein the plurality of free-spinning magnetized elements are arranged into at least two groups of free-spinning magnetized elements.
7. The device of claim 1 , wherein the plurality of interpole elements comprise a plurality of free-spinning magnetized cylinders.
8. The device of claim 1 , wherein the plurality of interpole elements comprise a plurality of magnetizable wedges.
9. The device of claim 8 , wherein the plurality of magnetizable wedges are arranged into at least two groups of magnetizable wedges.
10. The device of claim 1 , wherein the individually rotatable magnetized elements are driven by a motor that is controlled by a controller to synchronize the speed and position of each magnetized element.
11. The device of claim 10 , wherein the controller is configured to adjust relative angular positions of each individually rotatable magnetized element relative to neighboring individually rotatable magnetized elements.
12. The device of claim 11 , wherein the second number of magnetic pole pairs is based on the relative angular positions.
13. The device of claim 1 , wherein the first gear member comprises an outer gear ring and the second gear member comprises an inner gear ring.
14. A method of varying a magnetic gear ratio of a magnetic gear, the method comprising:
selectively adjusting a relative rotation angle of a plurality of individually rotatable magnetized elements to generate a number of magnetic pole pairs of a first gear member; and
harmonically coupling the magnetic pole pairs of the first gear member with magnetic pole pairs of a second gear member for at least two numbers of magnetic pole pairs of the first gear member from the selectively adjusting.
15. The method of claim 14 , wherein the harmonically coupling the first gear member with the second gear member comprises harmonically coupling using a plurality of interpole elements between the first and second gear members.
16. The method of claim 15 , wherein the interpole elements are chosen from free-spinning magnetized cylinders and magnetizable wedges.
17. The method of claim 15 , wherein the harmonically coupling the first gear member with the second gear member comprises harmonically coupling using a plurality of interpole elements arranged into at least two groups.
18. A system comprising:
the magnetic gear of claim 1 ;
a high speed, low torque input shaft operatively coupled to a high speed gear ring of the magnetic gear;
a low speed, high torque output shaft operatively coupled to a low speed gear ring of the magnetic gear
rotary equipment associated with an oil drilling rig operatively coupled to be driven by the output shaft.
19. The system of claim 18 , wherein the rotary equipment is chosen from a top drive, a mud pump, and a drawworks.