Drive systems for retractable vehicle step
View Patent ↗A retractable step assist for a vehicle comprises a step, an actuator, an optical fiber sensor, and a safety. The step is movable between a retracted position and a deployed position that is downward and outboard from the retracted position. The actuator is mechanically connected to the step to position the step. The optical fiber sensor has an output that varies when pressure is applied to the optical fiber sensor. The safety is triggered by this output from the optical fiber sensor. The safety is configured to terminate retraction of the step when the optical fiber sensor senses pressure from an object pinched by the step deck.
1. A drive system for use with a retractable vehicle step having (i) a first arm with an upper portion rotatably mountable with respect to an underside of a vehicle so as to be rotatable about a first axis of rotation and (ii) a step member rotatably connected to said first arm so as to be movable in an inboard-outboard direction of movement between a retracted position and an extended position, said first axis being transverse to said inboard-outboard direction of movement, said drive system comprising:
an electric motor having an armature configured to rotate about an armature axis generally parallel to said first axis;
a pinion gear drivingly connected with respect to said motor, said pinion gear having a first outside diameter; and
an output gear in meshing engagement with said pinion gear, said output gear having a second outside diameter;
wherein said pinion gear and said output gear achieve a gear reduction of at least 3:1, and the larger of said first outside diameter and said second outside diameter is no more than 3.0 times the smaller of said first outside diameter and said second outside diameter.
2. The system of claim 1 , wherein said output gear is configured to rotate about said first axis.
3. The system of claim 1 , wherein said pinion gear is configured to rotate about a pinion axis generally parallel to said inboard-outboard direction of movement.
4. The system of claim 1 , wherein said output gear comprises a helical gear.
5. The system of claim 1 , wherein the larger of said first outside diameter and said second outside diameter is no more than 2.0 times the smaller of said first outside diameter and said second outside diameter.
6. The system of claim 1 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.5 times the smaller of said first outside diameter and said second outside diameter.
7. The system of claim 1 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.2 times the smaller of said first outside diameter and said second outside diameter.
8. The system of claim 1 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.1 times the smaller of said first outside diameter and said second outside diameter.
9. The system of claim 1 , wherein said output gear and said pinion gear achieve a gear reduction of at least 5:1.
10. The system of claim 1 , further comprising an output shaft on which said output gear is mounted, and a tolerance ring coupling said output gear to said output shaft.
11. The system of claim 3 , wherein said armature axis is located inboard of said first axis.
12. A drive system for use with a retractable vehicle step configured to be associated with an outboard edge of a vehicle, said step having a lateral axis oriented generally parallel to said outboard edge, said drive system comprising:
an electric motor having an armature configured to rotate about an armature axis;
a pinion gear drivingly connected with respect to said motor, said pinion gear having a first outside diameter;
an output gear in meshing engagement with said pinion gear, said output gear having a second outside diameter; and
an output shaft having a drive end configured for driving engagement with said retractable vehicle step, said output gear mounted on said output shaft, said output shaft configured to rotate about an output shaft axis generally parallel to said armature axis and said lateral axis;
wherein said pinion gear and said output gear achieve a gear reduction of at least 3:1, and the larger of said first outside diameter and said second outside diameter is no more than 3.0 times the smaller of said first outside diameter and said second outside diameter.
13. The drive system of claim 12 , wherein the larger of said first outside diameter and said second outside diameter is no more than 2.0 times the smaller of said first outside diameter and said second outside diameter.
14. The drive system of claim 12 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.5 times the smaller of said first outside diameter and said second outside diameter.
15. The drive system of claim 12 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.2 times the smaller of said first outside diameter and said second outside diameter.
16. The drive system of claim 12 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.1 times the smaller of said first outside diameter and said second outside diameter.
17. The drive system of claim 12 , wherein said pinion gear and said output gear achieve a gear reduction of at least 5:1.
18. The drive system of claim 12 , further comprising a retractable vehicle step drivingly connected with respect to said output shaft.
19. A drive system for use with a retractable vehicle step having (i) a first arm with an upper portion rotatably mountable with respect to an underside of a vehicle so as to be rotatable about a first axis of rotation and (ii) a step member rotatably connected to said first arm so as to be movable in an inboard-outboard direction of movement between a retracted position and an extended position, said first axis being transverse to said inboard-outboard direction of movement, said drive system comprising:
an electric motor having an armature configured to rotate about an armature axis generally parallel to said first axis;
a pinion gear drivingly connected with respect to said motor;
an output gear in meshing engagement with said pinion gear; and
an output shaft having a drive end configured for driving engagement with said retractable vehicle step, said output gear mounted on said output shaft, said output shaft configured to rotate about an output shaft axis; and
a breakaway member connecting said output gear to said output shaft, said breakaway member preventing relative angular motion of said output gear and said output shaft, except in response to application of a breakaway torque to one of said output gear and said output shaft.
20. The drive system of claim 19 , wherein said breakaway member comprises a cylindrical spring member.
21. The drive system of claim 19 , wherein said breakaway member comprises a tolerance ring.
22. The drive system of claim 20 , wherein said spring member is positioned between an outside diameter of said output shaft and an inside diameter of said output gear.
23. The drive system of claim 20 , wherein said spring member forms a number of ridges extending generally parallel to said output shaft axis.
24. The drive system of claim 23 , wherein at least one of said ridges forms an apex which bears against one of an outside diameter of said output shaft and an inside diameter of said output gear.
25. A drive system for use with a retractable vehicle step having (i) a first arm with an upper portion rotatably mountable with respect to an underside of a vehicle so as to be rotatable about a first axis of rotation oriented generally parallel to the ground and (ii) a step member rotatably connected to said first arm so as to be movable generally along an inboard-outboard axis between a retracted position and an extended position, said drive system comprising:
an electric motor having an armature configured to rotate about an armature axis generally parallel to said first axis;
a pinion gear drivingly connected with respect to said motor, said pinion gear having a first outside diameter; and
an output gear in meshing engagement with said pinion gear, said output gear having a second outside diameter;
wherein said pinion gear and said output gear achieve a gear reduction of at least 3:1, and the larger of said first outside diameter and said second outside diameter is no more than 3.0 times the smaller of said first outside diameter and said second outside diameter and wherein said pinion gear and said output gear comprise crossed helical gears.
26. The system of claim 25 , wherein said pinion gear has a helix angle of about 75 degrees, and said output gear has a helix angle of about 15 degrees.
27. The system of claim 25 , wherein said output gear is configured to rotate about said first axis.
28. The system of claim 25 , wherein said pinion gear is configured to rotate about a pinion axis generally parallel to said inboard-outboard axis.
29. The system of claim 25 , wherein the larger of said first outside diameter and said second outside diameter is no more than 2.0 times the smaller of said first outside diameter and said second outside diameter.
30. The system of claim 25 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.5 times the smaller of said first outside diameter and said second outside diameter.
31. The system of claim 25 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.2 times the smaller of said first outside diameter and said second outside diameter.
32. The system of claim 25 , wherein the larger of said first outside diameter and said second outside diameter is no more than 1.1 times the smaller of said first outside diameter and said second outside diameter.
33. The system of claim 25 , wherein said output gear and said pinion gear achieve a gear reduction of at least 5:1.
34. The system of claim 25 , further comprising an output shaft on which said output gear is mounted, and a tolerance ring coupling said output gear to said output shaft.
35. The system of claim 28 , wherein said armature axis is located inboard of said first axis.