Patent Publication Number: US-8523281-B2

Title: Reclining mechanism for vehicle seats

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a U.S. national phase of PCT Appln. No. PCT/US2009/036123, filed Mar. 5, 2009, the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates reclining mechanisms for vehicle seating assemblies and, more specifically, to manually operated reclining mechanisms. 
     2. Background Art 
     Vehicle seats normally include a seat base and a seat back that are connected by a reclining mechanism that allows the seat back to be positioned to accommodate different body types and the personal comfort of seat occupants. Reclining mechanisms for vehicle seats permit the seat back to pivot to allow a passenger to recline or incline the seat. 
     Manually operated reclining mechanisms have a locked position in which the seat back cannot pivot and an unlocked position in which the seat back can be pivoted. The reclining mechanism is manually moved from a locked position to an unlocked position. Full engagement of the reclining mechanism must be assured in the locked position after adjusting the reclining mechanism. 
     Reclining mechanisms must meet or exceed performance specifications and must be simple for customers to use. The components of reclining mechanisms must be manufactured to close tolerances to assure acceptable performance. Components that do not meet tolerances requirements for components may lead to inconsistent results, unacceptable levels of scrap, and other manufacturing problems. 
     Recliner mechanisms generally include a gear plate and a guide plate that rotate relative to each other. Both plates may be formed of metal in a fine blanking operation to meet the required close tolerances. The gear plate and the guide plate may create a scraping noise when the recliner is used to adjust the position of the seat back. The scraping noise is caused by metal-to-metal contact between the gear plate and the guide plate. If the guide plate has a bearing surface proximate the gear teeth of the gear plate, there is a substantial likelihood of a scraping noise being created by the guide plate coming into contact with the gear teeth. 
     The present invention is directed to overcoming the above problems and other problems that are addressed by this invention as summarized below. 
     SUMMARY OF THE INVENTION 
     A reclining mechanism for a vehicle seat is provided that has a guide plate adapted to be secured to one of a seat bottom or a seat back and a gear plate adapted to be secured to the other of the seat bottom or seat back. The gear plate is pivotally connected to the guide plate about a pivotal axis. The gear plate is provided with a plurality of gear teeth. A cam is provided that is pivotally connected to the gear plate. The cam has at least two cam surfaces. At least two lock elements are provided that cooperate with the guide plate and the cam for translation relative to the guide plate. The lock elements each have an external gear segment on a radially outwardly oriented portion of each lock element that cooperate with the gear teeth. The lock elements each provide an engagement element that cooperate with the cam pawl. Rotation of the cam causes the engagement elements of the cam surfaces to move the lock elements radially inwardly. The external gear teeth are unlocked from each of the internal gear teeth when the lock elements are moved radially inwardly. Two springs are provided on the guide plate for urging the cam to drive the external gear teeth into engagement with the internal gear teeth. A clip is assembled into an opening that forms an inner diameter of the gear plate. The clip forms a bearing surface upon which the gear plate rotates relative to the guide plate. 
     A reclining system for use in a vehicle is provided that has a pair of reclining mechanisms. Each of the pair of reclining mechanisms includes a guide plate that is adapted to be secured to one of a seat bottom or a seat back and a gear plate that is adapted to be secured to the other of the seat bottom or seat back. The gear plate is connected to the guide plate to pivot about a pivotal axis. The gear plate is provided with internal gear teeth. A cam is provided with at least two cam surfaces. Two lock elements cooperate with the guide plate and the cam. The lock elements each have a radially outwardly oriented gear segment that engages the internal gear teeth. Each of the lock elements have an engagement element that cooperates with one of the cam surfaces. The cam is rotated to cause the cam surfaces to contact the engagement elements of the lock elements to unlock the external gear teeth from the internal gear teeth. Springs are provided that cooperate with the guide plate and the cam to urge the cam to translate the lock element which causes external gear teeth to engage the internal gear teeth of the gear plate. A bushing causes the cam to rotate about the pivotal axis. The bushing is configured to receive a shaft that connects one of the reclining mechanisms to a second reclining mechanism. A clip is assembled between the bushing and the gear plate. The clip provides a bearing surface for the gear plate that receives the clip within an inner diameter of an opening in the gear plate. 
     A seat assembly for use in a vehicle is provided with a seat bottom, a seat back, a pair of reclining mechanisms and a shaft. A bushing receives a shaft that connects the pair of reclining mechanisms. Each of the reclining mechanisms has a guide plate that is adapted to be secured to the seat bottom and a gear plate that is adapted to be secured to the seat back which is pivotally connected to the guide plate about a pivotal axis. Each gear plate is provided with internal gear teeth and has an inner diameter. A cam is provided that has at least two cam surfaces. Two lock elements are moved by the cam relative to the guide plate. The lock elements each have an external gear segment that faces radially outwardly to cooperate with one of the internal gear teeth. The cam engages each lock element at two contact points to drive the external gear teeth into the internal gear teeth when the pair of reclining mechanisms is in a locked position. The lock elements each have an engagement element that cooperates with the cam pawl. The cams rotate to cause the cam surfaces to engage the engagement elements at one contact point to move the lock elements. The cam is pivoted to unlock the external gear teeth from the internal gear teeth. Two springs cooperate with the guide plate and the cam to urge the cam to move the external gear teeth into engagement with the internal gear teeth. A retainer clip is attached to the bushing and has a bearing surface that receives the inner diameter of the gear plate. 
     These and other features of the invention will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a seat assembly; 
         FIG. 2  is an inside elevation view of one embodiment of a gear plate of a reclining mechanism; 
         FIG. 3  is an inside elevation view of the guide plate, cam, locking elements, and springs of the reclining mechanism of  FIG. 2 ; and 
         FIG. 4  is a cross-sectional view of the reclining mechanism taken along the line  4 - 4  in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     Referring now to  FIG. 1 , a seat assembly is illustrated and referenced generally by numeral  20 . The seat assembly  20  includes a generally horizontal seat base  22 . The seat assembly  20  also includes an upright seat back  24 . A pair of reclining mechanisms  26 ,  26 ′ connect the seat base  22  to the seat back  24 . The reclining mechanisms  26 ,  26 ′ are connected together by a shaft  28 . The shaft  28  links the reclining mechanisms  26 ,  26 ′ so that a handle  29  may be used to lock or unlock the seat back  24  relative to the seat bottom  22 . 
     Referring to  FIG. 2 , the inner surface of a gear plate  30  is shown that forms part of the reclining mechanism  26 . The gear plate  30  has a ring of internal gear teeth  32  that are inwardly oriented teeth provided on an axially extending cylindrical surface of the gear plate  30 . An inner diameter  36 , or bearing surface, is defined by the gear plate  30 . The inner diameter  36  comprises a cylindrical surface of a central opening provided in the gear plate  30 . A plurality of welding lands  38  are arrayed about the inner diameter  36 . The welding lands  38  are intended to be welded to a seat back or seat base and may be welded by a MIG welder, laser welder, or the like. A case  40  extends across the width of the gear plate  30  to hold the reclining mechanism  26  together, as will be more fully described with reference to  FIGS. 3 and 4  below. 
     Referring to  FIG. 3 , the inside of a guide plate  42  is shown to include a plurality of guide features  44 , or guide sections. The guide features  44  are formed in the guide plate  42  in a metal stamping operation. The guide features  44  guide translational movement of locking elements  46 . The locking elements  46  are engaged by a cam  48 . Cam  48  includes a cam surface  50  that is adapted to engage a cam engagement surface  52  formed on one side of the locking elements  46 . The cam  48  is pivoted to cause the cam surface  50  to engage the cam engagement surface  52  of the locking elements  46  to move the locking elements radially inwardly and outwardly. Each of the locking elements  46  have a plurality of external teeth  53  that engage the internal teeth  32  when the locking elements are moved radially outwardly. 
     A hub  54  receives the gear plate  30 , guide plate  42  and cam  48 . Springs  56  are secured to spring retainers  58  that may be integrally formed on the guide plate  42 . The springs  56  engage spring engagement lobes  60  that are provided on the cam  48 . The springs  56  bias the cam  48  into the position shown in  FIG. 3  with the locking elements  46  being extended and external teeth  53  engage the inner teeth  32  shown in  FIG. 2 . 
     Referring more specifically to the cam surface  50  and cam engagement surface  52 , a pair of shoulders  62  are formed on the cam  48  on opposite sides of a cam hook  64 . The shoulders  62  engage the cam engagement surface  52  of the locking elements  46  at two spaced engagement points  68 . A hook receiver  70  is provided between the two spaced engagement points  68  for receiving one of the cam hooks  64 . The cam hooks  64  are rotated into engagement with the hook receiver  70  to pull the locking elements  46  radially inwardly while being guided by the guide features  44 . 
     Referring to  FIG. 4 , a clip  74  is shown to provide a bearing surface  76  against which the inner diameter/bearing surface  36  bears as the reclining mechanism  26  is manipulated. The clip  74  includes a lip  80  that is received in a groove  82  formed in the hub  54 . The lip  80  retains the reclining mechanism  26  on the hub  54  by capturing the reclining mechanism  26  between clip  74  and a radial flange  84  that is formed to extend radially outwardly from the other parts of the hub  54 . 
     A bearing surface  86  is provided on the hub  54  that is engaged by an inner diameter  88  of the guide plate  42 . The guide plate  42  is permitted to rotate relative to the hub  54  with the inner diameter  88  of the guide plate  42  riding on the bearing surface  86  formed on the hub  54 . 
     A cam receiving ring  90  is provided on the hub  54  for receiving the cam  48 . The cam  48  is non-rotatably secured to the cam receiving ring  90  by means of splines or other connecting elements so that as the hub  54  is pivoted, the cam  48  is positively engaged by the hub  54 . 
     The handle  29  is used to pivot the hub  54 . The handle  29  may be secured to the hub  54  by means of splines (not shown) as is well known in the art. 
     The gear plate  30  is secured to the guide plate  42  by means of the case  40 . Case  40  is a cup-shaped annular member that includes an axially extending rim  94  and a radially inwardly extending flange  96 . The axially extending rim  94  is welded or otherwise secured to the guide plate  42 . The radially inwardly extending flange  96  of the case  40  extends on the other side of the gear plate  30  from the guide plate  42  and captures the gear plate between the radially inwardly extending flange  96  and the guide plate  42 . A plastic ring may be provided inside the radially inwardly extending leg to reduce friction. The ring may be formed of polytetrafluoroethylene (PTFE) to further reduce friction and promote smooth movement of the gear plate  30  relative to the guide plate  42  when the recliner  26  is adjusted. 
     As shown in  FIG. 4 , a substantial space is provided between the guides  44  and the teeth  32  to prevent unwanted noise caused by the teeth  32  engaging the guides  44  as the gear plate  30  is rotated relative to the guide plate  42 . The inner diameter  36  of the gear plate  30  tightly engages the bearing surface  76  of the clip  74  so that the gear plate  30  can rotate smoothly relative to the guide plate  42 . 
     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.