Gearbox for vehicle seat adjustment mechanism
A vehicle seat adjustment mechanism may include a gearbox, a first gear, a second gear, and a spindle screw. The first gear is received in the gearbox and is rotatable relative to the gearbox about a first axis. The second gear is received in the gearbox and is rotatable relative to the gearbox about a second axis that is perpendicular to the first axis. The first and second gears are meshingly engaged with each other. The spindle screw is meshingly engaged with the second gear and extends through the second gear along the second axis. The spindle screw may have trapezoidal threads.
1. A vehicle seat adjustment mechanism comprising:
a gearbox;
a first gear received in the gearbox and rotatable relative to the gearbox about a first axis;
a second gear received in the gearbox and rotatable relative to the gearbox about a second axis that is perpendicular to the first axis, wherein the first and second gears are meshingly engaged with each other; and
a spindle screw meshingly engaged with the second gear and extending through the second gear along the second axis,
wherein the spindle screw is selected from the group consisting of:
a first spindle screw having trapezoidal threads and defined by Tr 8×3 (P1.5) (8 mm nominal diameter, 3 mm lead, and 1.5 mm pitch),
a second spindle screw having trapezoidal threads and defined by Tr 9×3 (P1.5) (9 mm nominal diameter, 3 mm lead, and 1.5 mm pitch),
a third spindle screw having trapezoidal threads and defined by Tr 11×4 (P2) (11 mm nominal diameter, 4 mm lead, and 2 mm pitch), and
a fourth spindle screw having trapezoidal threads and defined by Tr 12×4 (P2) (12 mm nominal diameter, 4 mm lead, and 2 mm pitch).
2. The vehicle seat adjustment mechanism of claim 1 , further comprising a motor driving the first gear, wherein the motor has a maximum rotational velocity of 5,500 revolutions per minute.
3. The vehicle seat adjustment mechanism of claim 2 , wherein the gearbox, the first gear, and the second gear are configured to move along the second axis at one of:
(i) a comfort speed having a linear adjusting speed ranging from 17 mm/s to 22 mm/s,
(ii) a high speed having a linear adjusting speed ranging from 55 mm/s to 60 mm/s, or
(iii) a ultra-high speed having a linear adjusting speed ranging from 85 mm/s to 90 mm/s.
4. The vehicle seat adjustment mechanism of claim 3 , wherein the first gear is a cylindrical worm gear and the second gear is one of a helical gear or a single enveloping worm gear.
5. The vehicle seat adjustment mechanism of claim 4 , wherein a gear ratio of the first gear to the second gear is selected from the group consisting of: 3.333, 3.25, 3.2, 2.833, 2.8, 2.75, 2.6, 2.4, and 2.2.
6. The vehicle seat adjustment mechanism of claim 4 , wherein a gear ratio of the first gear to the second gear is selected from the group consisting of: 8.5, 7.5, 6.5, 5.667, 5.333, 4.667, 4.333, 3.667, and 3.333.
7. A seat track assembly comprising the vehicle seat adjustment mechanism of claim 1 , and further comprising a lower seat track and an upper seat track that is configured to engage the lower seat track and slide along a length of the lower seat track, wherein the gearbox is configured to be mounted to the upper seat track.
8. The vehicle seat adjustment mechanism of claim 1 , wherein the gearbox includes:
a first portion including a first body, the first body defining a first longitudinal recess and a first peripheral recess in fluid communication with the first longitudinal recess; and
a second portion including a second body, the second body define a second longitudinal recess and a second peripheral recess in fluid communication with the second longitudinal recess.
9. The vehicle seat adjustment mechanism of claim 8 , wherein:
the first body includes a first curved surface that is concave,
the second body includes a second curved surface, the second curved surface being convex and having an equal and opposite curvature compared to the first curved surface, and
in an assembled configuration:
the first curved surface is in contact with the second curved surface,
the first longitudinal recess communicates with the second longitudinal recess to define a longitudinal passage, and
the first peripheral recess communicates with the second peripheral recess to define a peripheral receptacle.
10. The vehicle seat adjustment mechanism of claim 9 , wherein the first curved surface and the second curved surface both define (i) a portion of an ellipsoidal surface, (ii) a portion of a conical surface, or (iii) a portion of a spherical surface.
11. The vehicle seat adjustment mechanism of claim 10 , wherein:
one of the first portion and the second portion includes a frusto-conical projection extending from a respective one of the first curved surface and the second curved surface,
the other of the first portion and the second portion includes a frusto-conical receptacle defined by a respective one of the first curved surface and the second curved surface, and
in the assembled configuration, the frusto-conical receptacle receives the frusto-conical projection.
12. The vehicle seat adjustment mechanism of claim 11 , wherein:
the one of the first portion and the second portion further includes an annular projection extending from the respective one of the first curved surface and the second curved surface, the annular projection being disposed around a base of the frusto-conical projection and coaxial with the frusto-conical projection,
the other of the first portion and the second portion further includes an annular depression defined by a respective one of the first curved surface and the second curved surface, the annular depression coaxial with the frusto-conical receptacle, and
in the assembled configuration, the annular depression receives the annular projection.
13. The vehicle seat adjustment mechanism of claim 12 , wherein the frusto-conical projection includes a first frusto-conical projection and a second frusto-conical projection, the frusto-conical receptacle includes a first frusto-conical receptacle and a second frusto-conical receptacle, the annular projection includes a first annular projection and a second annular projection, and the annular depression includes a first annular depression and a second annular depression.
14. The vehicle seat adjustment mechanism of claim 9 , further comprising an elastic layer disposed on at least one of the first curved surface or the second curved surface.
15. The vehicle seat adjustment mechanism of claim 9 , wherein:
one of the first portion and the second portion includes an integral rivet extending from a respective one of the first curved surface and the second curved surface, and
the other one of the first portion and the second portion includes an aperture defined in a respective one of the first curved surface and the second curved surface, the aperture being configured to receive a portion of the integral rivet.
16. The vehicle seat adjustment mechanism of claim 1 , wherein the spindle screw is the first spindle screw and has a minimum axial strength of 19 kN.
17. The vehicle seat adjustment mechanism of claim 1 , wherein the spindle screw is the second spindle screw and has a minimum axial strength of 25 kN.
18. The vehicle seat adjustment mechanism of claim 1 , wherein the spindle screw is the third spindle screw and has a minimum axial strength of 37 kN.
19. The vehicle seat adjustment mechanism of claim 1 , wherein the spindle screw is the fourth spindle screw and has a minimum axial strength of 45 kN.
20. A vehicle seat adjustment mechanism comprising:
a gearbox;
a first gear received in the gearbox and rotatable relative to the gearbox about a first axis;
a second gear received in the gearbox and rotatable relative to the gearbox about a second axis that is perpendicular to the first axis, wherein the first and second gears are meshingly engaged with each other;
a motor driving the first gear, wherein the motor has a maximum rotational velocity of 5,500 revolutions per minute; and
a spindle screw meshingly engaged with the second gear and extending through the second gear along the second axis,
wherein the spindle screw is selected from the group consisting of:
a first spindle screw having trapezoidal threads and defined by Tr 8×3 (P1.5) (8 mm nominal diameter, 3 mm lead, and 1.5 mm pitch),
a second spindle screw having trapezoidal threads and defined by Tr 9×3 (P1.5) (9 mm nominal diameter, 3 mm lead, and 1.5 mm pitch),
a third spindle screw having trapezoidal threads and defined by Tr 11×4 (P2) (11 mm nominal diameter, 4 mm lead, and 2 mm pitch), and
a fourth spindle screw having trapezoidal threads and defined by Tr 12×4 (P2) (12 mm nominal diameter, 4 mm lead, and 2 mm pitch),
wherein the gearbox includes:
a first portion including a first body, the first body defining a first longitudinal recess and a first peripheral recess in fluid communication with the first longitudinal recess; and
a second portion including a second body, the second body define a second longitudinal recess and a second peripheral recess in fluid communication with the second longitudinal recess,
wherein the first body includes a first curved surface that is concave,
wherein the second body includes a second curved surface, the second curved surface being convex and having an equal and opposite curvature compared to the first curved surface, and
wherein in an assembled configuration:
the first curved surface is in contact with the second curved surface,
the first longitudinal recess communicates with the second longitudinal recess to define a longitudinal passage, and
the first peripheral recess communicates with the second peripheral recess to define a peripheral receptacle.