Stamped splined locking mechanism for rotating automotive seat bracket

A vehicle seat rotates in response to activation of an electric motor. The electric motor is part of a non-back-drivable mechanism such that it acts to lock the seat in position. The seat mechanism is assembled from stamped components for efficient manufacturing. A bracket includes integrally formed gear teeth which mesh with gear teeth driven by the electric motor. The bracket is held between two stamped parts using four-point angular contact ball bearings. The races of the ball bearings are stamped into the respective stamped parts.

TECHNICAL FIELD

The present disclosure relates generally to a rotating mechanism for a vehicle seat, and more specifically to a mechanism including a stamped spline.

BACKGROUND

In some applications, it may be desirable for a vehicle seat to swivel, for example, 180 degrees. Vehicles, such as vans, may include these seats so that their seating configuration is flexible. When the vehicle is driven, the seat should be locked in a forward-facing direction. Additionally, in the forward-facing position, structural security standards are elevated due to crash-worthiness demands.

SUMMARY

A vehicle seat includes a stamped bracket, a base, and a plurality of rolling elements. The stamped bracket defines a first aperture. Internal gear teeth are integrally formed in the first aperture. The stamped bracket is adapted for fixation to a seat frame. The base is adapted for fixation to vehicle structure. The rolling elements are arranged between the base and the stamped bracket to locate the first aperture with respect to the base and to permit rotation of the stamped bracket with respect to the base about an axis of rotation. The rolling elements may be arranged along two circles, each circle centered on the axis of rotation. The base may include a lower stamping and an upper stamping wherein a portion of the rolling elements are arranged between the lower stamping and the stamped bracket and a remainder of the rolling elements are arranged between the stamped bracket and the upper stamping. A first bearing race may be integrally formed in a top surface of the lower stamping. A second bearing race may be integrally formed in a bottom surface of the stamped bracket. A third bearing race may be integrally formed in a top surface of the stamped bracket. A fourth bearing race may be integrally formed in a bottom surface of the upper stamping. The first through fourth bearing races may be shaped to establish four-point angular contact bearing assemblies. An electric-motor driven actuator may have a shaft with external gear teeth meshing with the internal gear teeth. The shaft may extend through a second aperture defined in the base. The electric-motor driven actuator may be non-back-drivable, thereby locking the seat in position when not electrically powered. J-channels may be stamped into each of the lower stamping and the stamped bracket such that the J-channels interlock when the seat is in a forward-facing position.

A method of manufacturing a vehicle seat includes stamping a bracket, providing a base, and arranging a plurality of rolling elements between the base and the bracket. The bracket defines a first aperture having internal gear teeth integrally formed therein. The bracket is adapted for fixation to a seat frame. The rolling elements locate the first aperture with respect to the base and permit rotation of the bracket with respect to the base about an axis of rotation. Providing the base may include stamping a lower part, stamping an upper part, and fastening the lower part to the upper part after arranging the plurality of rolling elements. Stamping the lower part may include forming a first bearing race in a top surface of the lower part. Stamping the bracket may include forming a second bearing race in a bottom surface of the bracket and forming a third bearing race in a top surface of the bracket. Stamping the upper part may include forming a fourth bearing race in a bottom surface of the upper part. A portion of the rolling elements may be placed between the first and second bearing races and a remainder of the rolling elements may be placed between the third and fourth races. J-channels may be formed into the lower part and the bracket such that they engage each other when the vehicle seat is in a forward-facing position. An electric actuator may be inserted such that a shaft extends through a second aperture formed in the base and external gear teeth fixed to the shaft mesh with the internal gear teeth.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It should be appreciated that like drawing numbers appearing in different drawing views identify identical, or functionally similar, structural elements. Also, it is to be understood that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

The terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the following example methods, devices, and materials are now described.

FIG. 1schematically illustrates a motorized swiveling vehicle seat. The seat is attached to vehicle structure such as floorpan10. The seat swivels about axis12in response to operation of an electric motor driven actuator14. A base assembly16is rigidly attached to the vehicle structure. As noted below, base assembly16is fabricated from two stampings30and32which are fastened to one another during assembly of the seat mechanism. A bracket18is supported, via bearings, to rotate with respect to the base assembly about the axis12. The actuator is mounted to vehicle structure and projects through a hole in the base assembly to interface with the bracket to adjust a rotational position of the seat. A seat frame20is rigidly fixed to the bracket and supports a seat cushion22and a seat back24.

FIG. 2is an exploded view of the support mechanism, including the base assembly16and the bracket18. Base assembly16includes a lower stamping30and an upper stamping32fastened to one another by bolts34and nuts36. The lower stamping30includes a hole38through which the actuator projects. The lower stamping30is separated from the bracket18by a first set of ball bearings40. The upper stamping32is separated from the bracket18by a second set of ball bearings42. The ball bearings are situated along two circles and guided by circular bearing races formed in the lower stamping, bracket, and upper stamping. In cross section, the bearing races are shaped such that each ball contacts each respective race in two positions, thereby forming four-point angular contact ball bearing assemblies. The four-point angular contact bearings may be pre-loaded to resist relative radial movement between the races without play.

Fabrication and assembly of the support mechanism is illustrated byFIGS. 3-5.FIG. 3shows lower stamping30. Lower stamping30is formed from flat sheet metal stock by a sequence of stamping operations. Some operations cut the sheet metal stock while other operations bend the metal to a desired shape. Several features of note are formed into lower stamping30by the stamping process. A first set of holes50are formed which provide for eventual fixation to vehicle structure. A second set of holes52are formed which enable eventual bolting to upper stamping32. As previously mentioned, a hole38is formed on one side for actuator14. A circular groove54is formed in the top surface to act as a bearing race for ball bearings40. Finally, a set of J-channels56are formed. As discussed later, these engage with J-channels formed in the bracket to provide greater security when the seat is in the forward-facing position.

FIG. 4shows the bracket18which is also formed by a stamping process. Bracket18includes a central opening with internal gear teeth60. This opening and these gear teeth are integrally formed during the stamping process, reducing cost relative to provision of a separate component formed by conventional gear tooth manufacturing methods. Flanges62are formed on front and rear sides of the bracket. Holes64in flanges62facilitate eventual attachment of the seat frame20. A circular groove66is formed in the bottom surface to act as a bearing race for ball bearings40. During assembly, ball bearings40are placed in groove54of the lower stamping and then bracket18is positioned such that the balls are in groove66. Another circular grove68is formed in the top surface to act as a bearing race for ball bearings42.

A set of J-channels70are formed in bracket18. J-channels70project downward from bracket18. Each J-channel70includes an outward projecting lip. J-channels56project upwards from lower stamping30and include an inward projecting lip. When the bracket is aligned with the lower stamping, in the position illustrated inFIG. 4, the J-channels interlock. This resist forces that would pull the bracket upwards or tilt the bracket during a vehicle collision. Preferably, the seat is in this position during driving. In normal operation, the bearings provide sufficient support in any rotational position of the seat. During assembly of bracket18to lower stamping30, bracket18is first brought into contact with the bearing in a rotated position and then rotated into the position shown inFIG. 4.

FIG. 5shows the upper stamping. Holes72line up with holes52. A circular groove74is formed in the bottom surface to act as a bearing race for ball bearings42. During assembly, ball bearings42are placed in groove68of bracket18and then upper stamping32is positioned such that the balls are in groove74. Then, bolts34and nuts36are installed to complete assembly of the support mechanism. The stamped parts may also include a network of ridges to add stiffness.

FIG. 6illustrates the position of the actuator after the support mechanism is installed in the vehicle. An external gear80is attached to an electric motor rotor shaft. The external gear teeth of gear80mesh with the internal gear teeth60. When the motor is powered, seat bracket18rotates in response. Motor-driven actuator14is designed such that it is not back-drivable. In other words, it resists rotation when not electrically powered. Therefore, the actuator acts as a position-lock whenever the motor is not electrically powered.