Valve with magnetic detents

1. A motor, comprising:

a piston disposed within a cylinder;

a first pilot valve disposed in a first end of the cylinder;

a second pilot valve disposed in a second end of the cylinder opposite the first end; and

a main valve configured to control a flow of a fluid into the cylinder, wherein the main valve comprises:

a housing;

a valve member disposed in the housing; and

a magnetic detent configured to resist movement of the valve member within the housing by applying a magnetic force to the valve member;

wherein the first and second pilot valves are configured to be actuated by the piston.

2. The motor of claim 1 , wherein the valve member comprises a spool valve.

3. The motor of claim 1 , wherein the main valve comprises a shock absorber disposed in the housing near an end of a path through which the valve member is configured to travel.

4. The motor of claim 3 , wherein the shock absorber comprises polyurethane.

5. The motor of claim 1 , wherein the main valve is configured to alternate an airflow between opposing sides of the piston.

6. The motor of claim 1 , wherein the valve member seals directly against the housing without intervening sealing members.

7. The motor of claim 1 , wherein the housing is coupled to a first side of the cylinder via a first fluid passage and a second side of the cylinder via a second fluid passage, wherein the first side is on a different side of the piston from the second side.

8. The motor of claim 1 , wherein the magnetic detent comprises a static magnet coupled to the housing and a moving magnet coupled to the valve member, wherein the moving magnet moves with the valve member, and wherein the moving magnet and static magnet are oriented such that they have opposite magnetic poles facing each other.

9. The motor of claim 1 , wherein the magnetic detent comprises a magnet coupled to the housing and wherein the valve member comprises a magnetically responsive material.

10. The motor of claim 1 , wherein the magnetic detent comprises a magnet coupled to the valve member and a magnetically responsive material coupled to the housing.

11. The motor of claim 1 , comprising another magnetic detent, wherein the magnetic detents are disposed on opposite sides of the valve member.

12. A valve, comprising:

a housing;

a spool valve disposed in the housing, the spool valve comprising a middle seal that defines an upper chamber and a lower chamber in the housing; and

a magnetic detent between the housing and the spool valve, wherein the magnetic detent comprises a stationary magnet coupled to the housing, wherein the spool valve comprises a magnetically responsive material, and wherein the spool valve is configured to be magnetically biased by the stationary magnet.

13. The valve of claim 12 , wherein the housing comprises:

a primary fluid intake positioned to flow fluid into either the upper chamber or the lower chamber, depending on the position of the middle seal;

an upper fluid outlet in fluid communication with the upper chamber; and

a lower fluid outlet in fluid communication with the lower chamber.

14. The valve of claim 13 , wherein the spool valve is biased against the housing by the magnetic detent such that the middle seal is disposed on a side of the primary fluid intake.

15. The valve of claim 12 , wherein the spool valve does not comprise a magnet.

16. A method of operating an air motor, the method comprising:

magnetically biasing a valve member in a housing against a first side of the housing to hold the valve member in a first position;

directing a fluid flow to a first end of a cylinder having a piston disposed therein when the valve member is in the first position, wherein the fluid flow drives the piston from a first end of the cylinder to a second end of the cylinder opposite the first end;

actuating a first pilot valve disposed in the second end of the cylinder via the piston; and

pneumatically overcoming the magnetic bias by adjusting a pressure of a fluid in contact with the valve member to drive the valve member to a second position in response to the actuation of the first pilot valve.

17. The method of claim 16 , comprising magnetically biasing the valve member against an opposing side of the housing in the second position.

18. The method of claim 17 , comprising pneumatically driving the valve member back to the first position.

19. The method of claim 16 , comprising absorbing energy with a shock absorber when the valve member reaches the second position.

20. The method of claim 16 , comprising:

magnetically biasing the valve member against a second side of the housing to hold the valve member in the second position;

directing the fluid flow to a second end of the cylinder when the valve member is in the second position, wherein the fluid flow drives the piston from the second end of the cylinder back to the first end of the cylinder;

actuating a second pilot valve disposed in the first end of the cylinder via the piston; and

pneumatically overcoming the magnetic bias by adjusting the pressure of the fluid in contact with the valve member to drive the valve member back to the first position in response to the actuation of the first pilot valve.