BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prospective view of a vehicle seat provided with a tilt adjustment apparatus made according to the present invention;
FIG. 2 is an exploded perspective view of the tilt adjustment apparatus;
FIG. 3 is a side elevation view of the tilt adjustment apparatus;
FIG. 4 is a cross-sectional view taken in a radially extending plane through the tilt adjusting apparatus; and
FIG. 5 is a perspective view of the tilt adjusting apparatus.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Referring to FIG. 1, the vehicle seat 10 is illustrated that includes a seat base 12 and a seat back 14 that are interconnected by a tilt adjuster 16, or tilt adjustment apparatus. The tilt adjuster 16 is driven by a motor 18 by means of a flexible drive shaft 20 that is shown diagrammatically in FIG. 1. It should be noted that two tilt adjusters 16 are shown in FIG. 1.
Referring to FIG. 2 tilt adjuster 16 is shown in an exploded perspective view. An inner gear plate 24 and an outer gear plate 26 are shown separated from each other. A driver 28 is provided on the outer side of the outer gear plate 26. A cam ring 20 which is received within the outer gear plate 26 supports the first and second wedges 32 and 34 within a bearing ring 36. A spring 40 is operatively interposed between the first and second wedges 32 and 34 to bias the wedges 32, 34 into engagement with the cam ring 30 and bearing ring 36. A driver cap 42 is provided on the opposite side of the inner gear plate 24 that is secured to the driver 28 to hold the tilt adjuster 16 together. A dust cap 44 is provided between the outer gear plate 26 and the driver 28 to shield the component parts of the tilt adjuster 16 from contaminants.
The inner gear plate 24 is provided with a plurality of internal gear teeth 48. The inner gear plate 24 also has a central bore 50 in which the driver 28 is partially received. Rivet receiving openings 52 are provided in the inner gear plate 24 to secure the inner gear plate 24 to the seat base 12 as shown in FIG. 1. The outer gear plate 26 has a plurality of external gear teeth 56 that are engaged at a single meshing point with internal gear teeth 48 of the inner gear plate 24. The number of external teeth 56 is less than the number of internal gear teeth 48. The number of external gear teeth 56 may be at least one tooth less than the number of internal gear teeth 48. The central axis of the internal gear teeth 48 and the external gear teeth 56 are offset relative to each other. A bearing bore 58 is defined by the outer gear plate 26 that receives the bearing ring 36. The outer gear plate 26 also has rivet opening 60 in which rivets 54, or other fasteners, are received to secure the outer gear plate 26 to the seat back 14.
The cam ring 30 includes a driving protrusion 64 that extends radially outwardly from the cam ring. A locking peripheral section 66 is also provided on the cam ring 30 that extends radially outwardly from an outer diameter 68 of the cam ring 30.
The wedges 32, 34 each include a bearing engaging surface 72 and a cam engaging surface 74. Notches 76 are provided in the wedges 32 and 34 that receive first and second axially extending ends 78, 80 of the spring 40.
The driver 28 includes first and second driver segments 84, 86 that are assembled to the cam ring 30 on the surface designated as the outer diameter 68 of the cam ring 30. The first driver segment 84 and second driver segment 86 are inserted between the driver protrusion 64 and one of the first and second wedges 32, 34. The driver also includes a drive shaft receiving bore 88 that has a plurality of splines 90 that are engaged by splines 92 formed on the drive shaft 20.
Referring to FIGS. 3 and 4, operation of the tilt adjuster 16 will be described. When a seat occupant wishes to change the angular orientation of the seat back 14 the motor 18 is actuated to rotate the drive shaft 20. With reference to FIGS. 3 and 4, the drive shaft 20 rotates the driver 28, for example in the clockwise direction and the first and second driver segments 84, 86 move with the driver freely until the second driver segment 84 contacts the driving protrusion 64, of the cam 30. The second driver segment 86, in turn, contacts the first wedge 32. At this point, the wedge 32 moves toward the wedge 34 against the biasing force exerted by the spring 40. The wedges 32, 34 are at this point released from the bearing ring and the entire cam assembly including the cam ring 30, first wedge 32 and second wedge 34 slip on the bearing ring 36 allowing the outer gear plate 26 to rotate relative to the inner gear plate 24. The external gear teeth 56 rotate on the internal gear teeth 48 to change the point of engagement of the inner gear plate 24 and outer gear plate 26. The first and second driver segments 84 and 86 each include a radially extending face 94 that may engage a radially extending end 96 formed on each of the wedges 32 and 34.
To operate the locking mechanism in the opposite direction the drive shaft 20 is rotated in the counterclockwise direction and the cam assembly is rotatable in the opposite direction. First driver segment 84 engages the driving projection 64. Second driver segment 86 engages the second wedge 34 with the radially extending face of the second driver segment 86 engaging the radially extending end 96 of the second wedge 34.
Referring to FIG. 5, the tilt adjuster 16 is shown assembled together. The tilt adjuster includes an inner gear plate 24 that is secured to the outer gear plate 26. The dust cap 44 is retained on the inner gear plate 24. The drive shaft receiving bore 88 and the splines 90 provided in the bore 88 are also shown in FIG. 5.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Patent Application
20080061616
