Patent Description:
The present invention relates to a disc recliner mechanism for use in an automotive vehicle.

Disc recliner mechanisms for use in an automotive vehicle are known in the art. Typical disc recliner mechanisms include a guide plate and a tooth plate with an outer lip, wherein the outer lip rotatably engages the guide plate and has a plurality of teeth extending radially inward therefrom. At least one pawl is mounted between the guide plate and tooth plate. The pawl includes a toothed outer edge and a radially inner cam surface. Often a cam is rotatably mounted between the guide plate and the tooth plate. The cam includes a radially outer cam profile with at least one cam lobe, and the cam lobe has an engagement surface for selectively engaging the radially inner cam surface of the pawl. Rotation of the cam moves the pawl between a first position in which the pawl engages the tooth plate to lock the disc recliner mechanism and a second position in which the pawl disengages the tooth plate to unlock the disc recliner mechanism. However, the disc recliner mechanisms known in the art can push grease radially outward from between the tooth plate and the guide plate due to a flat-to-flat contact area where the outer lip of the tooth plate rotatably engages the guide plate, leading to potential grease mitigation and increased friction. Furthermore, the disc recliner mechanisms known in the art can be difficult to operate efficiently due to increased friction when the cam engages the pawl at slow actuation speeds. <CIT> discloses a disc recliner mechanism according to the preamble of claim <NUM>.

According to the invention, a disc recliner mechanism is provided for use in an automotive vehicle. The disc recliner mechanism includes a guide plate and a tooth plate with an outer lip extending circumferentially therearound. The outer lip rotatably engages the guide plate and has a plurality of teeth extending radially inward therefrom. At least one pawl is mounted between the guide plate and tooth plate, and the pawl includes a toothed outer edge and a radially inner cam surface. A cam is rotatably mounted between the guide plate and the tooth plate. The cam includes a radially outer cam profile for selectively engaging the radially inner cam surface of the pawl. Rotation of the cam moves the pawl between an extended position in which the pawl engages the tooth plate to lock the disc recliner mechanism and a retracted position in which the pawl disengages the tooth plate to unlock the disc recliner mechanism. Additionally, the outer lip of the tooth plate includes a channel for retaining lubricant and reducing rotational friction between the tooth plate and the guide plate.

Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:.

Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a disc recliner mechanism for use in an automotive vehicle is shown generally at <NUM>. The disc recliner mechanism <NUM> includes a tooth plate <NUM> rotatably coupled to a guide plate <NUM>. A radially outer lip <NUM> extends circumferentially around the tooth plate <NUM> and includes an axially outer surface <NUM> and opposite, substantially parallel, radially outer and radially inner edges <NUM>, <NUM>. A plurality of teeth <NUM> extend radially inward from the inner edge <NUM> of the tooth plate <NUM>. A plurality of pawls <NUM> with opposite, substantially parallel, first and second sides <NUM>, <NUM> are oriented between a pair of guides 30a, 30b extending axially from the guide plate <NUM>. Each pair of guides 30a, 30b is laterally spaced apart and has opposing, substantially parallel, inner guiding surfaces 32a, 32b that engage the first and second sides of each pawl <NUM>, <NUM>. Each pawl <NUM> further includes a toothed radially outer edge <NUM> disposed between the first and second sides <NUM>, <NUM> that is capable of selectively and complementarily engaging the teeth <NUM> extending from the inner edge <NUM> of the tooth plate <NUM>.

The disc recliner mechanism <NUM> further includes a cam <NUM> rotatably mounted between the tooth plate <NUM> and the guide plate <NUM>. Referring to <FIG>, rotation of the cam <NUM> moves the pawls <NUM> between an extended position in which the toothed edges <NUM> of the pawls <NUM> engage the tooth plate <NUM> to lock the disc recliner mechanism <NUM> (shown in <FIG>) and prevent rotation of the tooth plate <NUM> relative to the guide plate <NUM>, and a retracted position in which the toothed edges <NUM> of the pawls <NUM> disengage the tooth plate <NUM> to unlock the disc recliner mechanism <NUM> (shown in <FIG>) and allow rotation of the tooth plate <NUM> relative to the guide plate <NUM>. The cam <NUM> includes a radially outer cam profile <NUM> with at least one cam lobe <NUM> for selectively engaging a radially inner cam surface <NUM> of the pawls <NUM>. The radially inner cam surface <NUM> is disposed on the pawls <NUM> opposite the toothed edge <NUM> and extends between the first and second sides <NUM>, <NUM>. At least one cam follower <NUM> is disposed on the inner cam surface <NUM> of the pawls <NUM>. The cam lobes <NUM> each have an engagement surface <NUM> that selectively contacts the inner cam surface <NUM> of the pawls <NUM> as the cam <NUM> is rotated.

Referring to <FIG>, at least one of the cam lobes <NUM> includes a notch <NUM> extending axially from a first end <NUM> to a second end <NUM> of the engagement surface <NUM> or between opposite axial sides of the cam <NUM>. The notch <NUM> creates a gap between the cam lobe <NUM> and the cam follower <NUM> to reduce friction during selective sliding engagement of the cam lobe <NUM> along the cam follower <NUM>. A control mechanism, such as a cam shaft <NUM> to which a handle or the like may be coupled, is attached to the cam <NUM> to facilitate rotation thereof. The cam shaft <NUM> also extends through a central aperture <NUM> in the tooth plate <NUM> and a central aperture <NUM> in the guide plate <NUM>. In a preferred embodiment, the outer cam profile <NUM> includes first and second cam lobes <NUM> that correspond to and engage first and second cam followers <NUM> disposed on the inner cam surface <NUM> of the pawls <NUM>. The notch <NUM> is disposed on the engagement surface <NUM> of the first cam lobe <NUM>. However, it is to be appreciated that the disc recliner mechanism <NUM> may include any number of notches <NUM> and any number of cam lobes <NUM> and cam followers <NUM> without varying the scope of the invention. Further, it is to be appreciated that the notch <NUM> may also be placed on any one or any number of the cam lobes <NUM> to control an amount of friction between the cam lobe <NUM> and cam follower <NUM> as desired without varying the scope of the invention.

A spring <NUM> is operatively coupled to the cam shaft <NUM> to rotatably bias the cam <NUM> in a first direction (counterclockwise when viewed from <FIG>) to move the pawls <NUM> to the extended position. However, it is to be appreciated that alternative means of biasing the pawls <NUM> to the extended position may be used without varying the scope of the invention. One potential alternative biasing means is a pair of springs <NUM>, where each spring <NUM> is operatively coupled to opposite sides of the cam <NUM>, as is described in <CIT>, the disclosure of which is hereby incorporated by reference in its entirety. Rotation of the cam <NUM> in the first direction by one or more of the springs <NUM> causes the cam lobes <NUM> to engage the cam followers <NUM>, thereby pushing the pawl <NUM> radially outward between the inner guiding surfaces 32a, 32b of the guides 30a, 30b to the extended position in which the toothed edge <NUM> of the pawls <NUM> engages the teeth <NUM> extending from the tooth plate <NUM> to lock the disc recliner mechanism <NUM>.

The control mechanism, cam shaft <NUM>, rotates the cam <NUM> in a second direction (clockwise when viewed from <FIG>) against a biasing force of the spring <NUM> to move the pawls <NUM> to the retracted position. A pawl retractor plate <NUM> is operatively mounted adjacent the cam <NUM> and rotates in tandem with the cam <NUM> and the cam shaft <NUM> to facilitate return of the pawls <NUM> to the retracted position. The pawl retractor plate <NUM> includes a plurality of slots <NUM> for receiving a pip <NUM> extending axially from each pawl <NUM>. Rotation of the pawl retractor plate <NUM> in the second direction due to corresponding rotation of the cam shaft <NUM> and cam <NUM> in the second direction thereby urges the pawls <NUM> to move radially inward as the pip <NUM> of each pawl <NUM> engages the slots <NUM> of the pawl retractor plate <NUM>. The pawls <NUM> are thereby moved to the retracted position in which the toothed edge <NUM> of the pawls <NUM> disengages the teeth <NUM> extending from the tooth plate <NUM> to unlock the disc recliner mechanism <NUM>. It is also to be appreciated that alternative means of returning the pawls <NUM> to the retracted position, including various cam lobe <NUM> and cam follower <NUM> configurations, may be used without varying the scope of the invention. One such potential configuration of cam lobes <NUM> and cam followers <NUM> used to return the pawls <NUM> to the retracted position is described in <CIT>.

Referring to <FIG>, a radially outer lip <NUM> extends circumferentially around the guide plate <NUM> and includes an axially outer surface <NUM> and opposite, substantially parallel, radially outer and radially inner edges <NUM>, <NUM>. The outer lip <NUM> of the guide plate <NUM> has an outer diameter larger than that of the outer lip <NUM> of the tooth plate <NUM>. Thus, the outer lip <NUM> of the tooth plate <NUM> nests within and is encapsulated by the outer lip <NUM> of the guide plate <NUM>. The tooth plate <NUM> and the guide plate <NUM> are thereby rotatably coupled such that the inner edge <NUM> of the guide plate <NUM> contacts the outer edge <NUM> of the tooth plate <NUM>, and the outer surface <NUM> of the tooth plate <NUM> rotatably engages the guide plate <NUM> at a planar surface <NUM> disposed substantially perpendicularly from the inner edge <NUM> of the guide plate <NUM>.

Referring to <FIG>, a channel <NUM> is recessed in and extends concentrically around the outer surface <NUM> of the tooth plate <NUM>. The channel <NUM> has a pair of substantially parallel radially outer and radially inner walls <NUM>, <NUM> with a channel floor <NUM> extending between the inner and outer walls <NUM>, <NUM>. The channel <NUM> eliminates flat-to-flat contact of and helps retain a lubricant, such as grease, between the tooth plate <NUM> and the guide plate <NUM>, thereby reducing mitigation of the lubricant and reducing friction between the tooth plate <NUM> and the guide plate <NUM>. A plurality of dividers <NUM> intersecting the channel <NUM> may be used to separate the channel <NUM> into multiple segments, as is shown in <FIG>. However, it is to be appreciated that the channel <NUM> may include any number of dividers <NUM> or may omit the dividers <NUM> entirely without varying the scope of the invention.

Referring to <FIG>, a stepped retaining ring <NUM> rotatably secures the tooth plate <NUM> to the guide plate <NUM> and includes a radially outer planar edge <NUM> and a radially inner planar edge <NUM> with a plurality of axially extending protrusions <NUM>. The outer planar edge <NUM> of the retaining ring <NUM> is attached to the outer surface <NUM> of the guide plate <NUM> by a weld <NUM> extending axially into the guide plate <NUM>. The protrusions <NUM> engage a rear planar surface <NUM> of the tooth plate <NUM> disposed opposite from and substantially parallel to the outer surface <NUM> of the tooth plate <NUM>, thereby preventing axial separation of the tooth plate <NUM> and the guide plate <NUM> while still allowing the tooth plate <NUM> to rotate relative to the guide plate <NUM>. Because the retaining ring <NUM> is coupled to the outer surface <NUM> of the guide plate <NUM> rather than, for instance, extending around the outer edge <NUM> of the guide plate <NUM>, the retaining ring <NUM> is ultimately inconsequential to the overall diameter of the disc recliner mechanism <NUM>.

The disc recliner mechanism <NUM> can be adapted for use in various capacities within the automotive vehicle. In one such capacity, the disc recliner mechanism <NUM> can be coupled between a seat back and a seat cushion in a seat assembly to allow selective pivotal movement of the seat back relative to the seat cushion. In another such capacity, the disc recliner mechanism <NUM> can be coupled between the seat cushion and a seat base for allowing the seat assembly to move between numerous positions, including a stowed position, an easy entry position, and a design position.

Referring to operation of the preferred embodiment of the disc recliner mechanism <NUM>, the cam shaft <NUM> is rotated in the second direction (clockwise when viewed from <FIG>) to overcome the biasing force of the spring <NUM> and simultaneously rotate the cam <NUM> and the pawl retractor plate <NUM> in the second direction. As the pawl retractor plate <NUM> rotates in the second direction, the slots <NUM> engage the pips <NUM> extending from the pawls <NUM> to move the pawls <NUM>, guided by the guiding surfaces 32a, 32b, radially inward to the retracted position. The toothed edge <NUM> of the pawls <NUM> disengages the teeth <NUM> extending from the tooth plate <NUM>, thereby unlocking the disc recliner mechanism <NUM> and allowing rotational movement between the guide plate <NUM> and the tooth plate <NUM>. A user may then rotate the disc recliner mechanism <NUM> to a desired position. Lubricant displaced radially outward during rotation between the guide plate <NUM> and the tooth plate <NUM> is trapped within the channel <NUM> extending concentrically around the outer surface <NUM> of the tooth plate <NUM> to continuously reduce rotational friction therebetween.

Once the user has selected the desired position for the disc recliner mechanism <NUM>, the biasing force of the spring <NUM> rotates the cam shaft <NUM> and cam <NUM> in the first direction (counterclockwise when viewed from <FIG>). As the cam <NUM> rotates in the first direction, the engagement surfaces <NUM> of the cam lobes <NUM> initially engage the cam followers <NUM>, pushing the pawls <NUM> radially outward, guided by the guiding surfaces 32a, 32b, toward the outer lip <NUM> of the tooth plate <NUM>. As the cam <NUM> continues to rotate and the engagement surfaces <NUM> of the cam lobes <NUM> slide further across the cam followers <NUM>, the first cam follower <NUM> skips across the notch <NUM> in the engagement surface <NUM> of the first cam lobe <NUM>, thereby reducing friction and easing return of the pawls <NUM> to the extended position. The cam <NUM> then comes to rest engaged with the pawls <NUM> such that the first cam lobe <NUM> is in full contact with the first cam follower <NUM>, and the second cam lobe <NUM> is in full contact with the second cam follower <NUM>. The pawls <NUM> are disposed in the extended position where the toothed edges <NUM> are engaged with the teeth <NUM> extending from the inner edge <NUM> of the tooth plate <NUM>, thereby locking the disc recliner mechanism <NUM> and preventing rotation of the tooth plate <NUM> relative to the guide plate <NUM>.

Claim 1:
A disc recliner mechanism (<NUM>) for use in an automotive vehicle, the disc recliner mechanism (<NUM>) comprising:
a guide plate (<NUM>);
a tooth plate (<NUM>) with an outer lip (<NUM>) extending circumferentially therearound, the outer lip (<NUM>) rotatably engaging the guide plate (<NUM>) and having a plurality of teeth (<NUM>) extending radially inward therefrom;
at least one pawl (<NUM>) mounted between the guide plate (<NUM>) and tooth plate (<NUM>), the pawl (<NUM>) including a toothed outer edge (<NUM>) and a radially inner cam surface (<NUM>); and
a cam (<NUM>) rotatably mounted between the guide plate (<NUM>) and the tooth plate (<NUM>), the cam (<NUM>) including a radially outer cam profile (<NUM>) for selectively engaging the radially inner cam surface (<NUM>) of the pawl (<NUM>), wherein rotation of the cam (<NUM>) moves the pawl (<NUM>) between an extended position in which the pawl (<NUM>) engages the tooth plate (<NUM>) to lock the disc recliner mechanism (<NUM>), and a retracted position in which the pawl (<NUM>) disengages the tooth plate (<NUM>) to unlock the disc recliner mechanism (<NUM>); and
characterised in that the outer lip (<NUM>) of the tooth plate (<NUM>) includes a channel (<NUM>) for retaining lubricant and reducing rotational friction between the tooth plate (<NUM>) and the guide plate (<NUM>).