Abstract:
A hub seal assembly includes a hub having a groove with a first radial wall, a first floating seal including a second radial wall, and a resilient element. The first floating seal is axially displaced by the resilient element so that the second radial wall contacts the first radial wall. In an example embodiment, the first floating seal includes polytetrafluoroethylene. In some example embodiments, the resilient element is an o-ring. In an example embodiment, the first floating seal includes a circumferential groove or a notch and the o-ring is at least partially disposed in the groove or the notch.

Description:
FIELD 
     The invention relates generally to a hub seal assembly, and more specifically to a hub seal assembly having a floating seal and a resilient element. 
     BACKGROUND 
       FIG. 2  is a top-half section view of torque converter  100  with a prior art hub seal configuration. 
       FIG. 3  is a detail view of region  3  in  FIG. 2  with an enlarged groove shown for clarity. The following should be viewed in light of  FIGS. 2 and 3 . Hub seals are known. Converter  100  is a twin plate design. That is, converter  100  includes piston plate  102  drivingly connected to cover  104  through leaf springs  106  and drive plate  108 . Cover  104  is drivingly connected to a prime mover (not shown), such as an automobile engine, at lugs  110 . Therefore, piston plate  102  is rotationally connected to the engine through cover  104 . 
     Drive plate  112  is axially disposed between piston plate  102  and cover  104  so that hydraulic pressure acting on piston plate  102  clamps drive plate  112  between piston  102  and cover  104 . Piston  102 , cover  104  and drive plate  112  may be collectively referred to as clutch assembly  114 . When clutch assembly  114  is engaged, torque from cover  104  is transmitted to damper  116  through tabs  118  of drive plate  112 . Tabs  118  engage complementary tabs  120  of cover plate  122  and torque is transmitted from plates  122  and  124  through springs  126  to plates  128  and  130 . Torque from plates  128  and  130  is transmitted to flange  132  through springs  134  and  135 . Flange  132  is fixed to hub  136  by riveting, staking, or welding, for example. Hub  136  is drivingly engaged with an input shaft (not shown) of a transmission (not shown) at splines  137 . Therefore, when clutch  114  is engaged, torque from the engine is transmitted to the input shaft through damper  116  and hub  136 . Piston plate  102  and hub  136  have the same relative speed except for minimal differences due to fluctuation in damper  116 . 
     When the vehicle is stopped, there is a considerable rotational speed difference between piston  102  and hub  136 . For example, when clutch  114  is disengaged and the vehicle is stopped, the engine rotational speed (and the piston rotational speed) may be 800 revolutions per minute (RPMs) or more, while the input shaft rotational speed (and the hub rotational speed) is 0 RPMs. Therefore, seal  138 , disposed in groove  140  and acting between piston  102  and hub  136 , must be specially designed for high relative speeds. For example, seal  138  may be a square-cut or rectangular-cut floating seal made of polytetrafluoroethylene (PTFE). By floating, I mean that the seal is disposed in groove  140  but is not compressed by radial walls  141  and  143  of groove  140 . That is, width  142  of seal groove  140  is greater than width  144  of floating seal  138  so that seal  138  is not tightly retained by groove  140 . Floating seals are generally preferred over compression seals to seal components with high relative speeds. 
     Seal  138  is disposed in groove  140 . Width  142  of groove  140  is greater than width  144  of seal  138  to ensure proper assembly of seal  138 . When hydraulic pressure is introduced to apply piston  102  and engage clutch  114 , some oil can leak past seal  138  as indicated by arrow  146 . This leakage degrades performance and reaction time of clutch  114 . Furthermore, once pressure builds seal  138  may move abruptly in direction of arrow  148  resulting in a rapid pressure rise and harsh engagement of clutch  114 . 
     BRIEF SUMMARY 
     Example aspects broadly comprise a hub seal assembly including a hub having a groove with a first radial wall, a first floating seal including a second radial wall, and a resilient element. The first floating seal is axially displaced by the resilient element so that the second radial wall contacts the first radial wall. In an example embodiment, the first floating seal includes polytetrafluoroethylene. In some example embodiments, the resilient element is an o-ring. In an example embodiment, the first floating seal includes a circumferential groove or a notch and the o-ring is at least partially disposed in the groove or the notch. 
     In an example embodiment, the hub seal assembly includes a second floating seal. The resilient element is disposed between the first and second floating seals. In some example embodiments, the resilient element includes a coil spring. In an example embodiment, the hub includes a notch and the coil spring is axially retained by the notch. 
     In some example embodiments, the hub seal includes a piston plate. The piston plate includes a first circumferential surface and the first floating seal includes a second circumferential surface in contact with the first circumferential surface. In an example embodiment, the hub seal includes a backing ring attached to the piston plate. The resilient element includes a coil spring and the backing ring axially retains the coil spring. In an example embodiment, the resilient element includes a diaphragm spring. 
     In some example embodiments, the hub seal assembly includes an annular ring with an axial tab extending therefrom, and the axial tab includes the resilient element. In an example embodiment, the hub seal assembly includes a piston plate and the annular ring is attached to the piston plate. In some example embodiments, the annular ring is axially retained by the hub. In an example embodiment, the hub seal assembly includes a flange fixed to the hub and a thrust washer attached to the flange. The annular ring is disposed between the flange and the thrust washer. 
     In some example embodiments, the hub seal assembly includes a snap ring with a first angled surface. The groove includes a second angled surface matingly engaged with the first angled surface and the snap ring includes the resilient element. In an example embodiment, engagement of the first angled surface with the second angled surface urges the snap ring towards the first seal. 
     Other example aspects broadly comprise a torque converter including a cover arranged for driving engagement with a prime mover, a piston plate drivingly engaged with the cover, a hub including a circumferential groove with a first width and a radial wall, and a dynamic seal disposed at least partially in the circumferential groove. The dynamic seal includes a circumferential surface contacting the piston plate, a surface in constant contact with the radial wall, and a second width less than the first width. In an example embodiment, the dynamic seal is urged into contact with the radial wall by an o-ring, a coil spring, a diaphragm spring, or an axial tab of an annular ring. In an example embodiment, the torque converter includes a wedge element at least partially disposed in the groove. The groove includes a first conical surface, the wedge element includes a second conical surface in contact with the first conical surface, and the wedge element is radially expanded by contact with the dynamic seal and the first conical surface. 
     Other example aspects broadly comprise a torque converter including a cover arranged for driving engagement with a prime mover, a piston plate drivingly engaged with the cover, a hub forming an output for the torque converter and including a circumferential groove with a first width and a radial wall, a dynamic seal and a resilient element. The dynamic seal is disposed at least partially in the circumferential groove and includes a second width less than the first width, a first surface engaged with the radial wall, and a circumferential surface engaged with the piston plate. The resilient element urges the first surface into contact with the radial wall and is selected from the group consisting of an o-ring, a coil spring, a diaphragm spring, and an axial tab of an annular ring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
         FIG. 1A  is a perspective view of a cylindrical coordinate system demonstrating spatial terminology used in the present application; 
         FIG. 1B  is a perspective view of an object in the cylindrical coordinate system of  FIG. 1A  demonstrating spatial terminology used in the present application; 
         FIG. 2  is a top-half section view of a torque converter with a prior art hub seal configuration; 
         FIG. 3  is a detail view of region  3  in  FIG. 2  with an enlarged groove shown for clarity; 
         FIG. 4  is a top-half section view of a torque converter with a hub seal configuration; 
         FIG. 5A  is a detail view of region  5  in  FIG. 4  with a seal design including an o-ring, according to an example aspect; 
         FIG. 5B  is a detail view of region  5  in  FIG. 4  with a seal design including two floating seals and an o-ring, according to an example aspect; 
         FIG. 5C  is a detail view of region  5  in  FIG. 4  with a seal design including two floating seals with circumferential grooves and an o-ring, according to an example aspect; 
         FIG. 5D  is a detail view of region  5  in  FIG. 4  with a seal design including a floating seals with a fillet and an o-ring, according to an example aspect; 
         FIG. 5E  is a detail view of region  5  in  FIG. 4  with a seal design including a floating seals with a notch and an o-ring, according to an example aspect 
         FIG. 5F  is a detail view of region  5  in  FIG. 4  with a seal design including a coil spring, according to an example aspect; 
         FIG. 5G  is a detail view of region  5  in  FIG. 4  with a seal design including a diaphragm spring, according to an example aspect; 
         FIG. 5H  is a detail view of region  5  in  FIG. 4  with a seal design including a coil spring and backing ring, according to an example aspect; 
         FIG. 5I  is a detail view of region  5  in  FIG. 4  with a seal design including an annular ring, according to an example aspect; 
         FIG. 5J  is a radial view of the annular ring of  FIG. 5I  taken generally along line J-J in  FIG. 5I ; 
         FIG. 5K  is a detail view of region  5  in  FIG. 4  with a seal design including an snap ring, according to an example aspect; 
         FIG. 5L  is a detail view of region  5  in  FIG. 4  with a seal design including an annular ring and a thrust washer, according to an example aspect. 
     
    
    
     DETAILED DESCRIPTION 
     At the outset, it should be appreciated that like drawing numbers appearing in different drawing views identify identical, or functionally similar, structural elements. Furthermore, it is understood that this invention is not limited only to the particular embodiments, methodology, materials and modifications described herein, and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
     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 invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the following example methods, devices, and materials are now described. 
       FIG. 1A  is a perspective view of cylindrical coordinate system  80  demonstrating spatial terminology used in the present application. The present invention is at least partially described within the context of a cylindrical coordinate system. System  80  has a longitudinal axis  81 , used as the reference for the directional and spatial terms that follow. The adjectives “axial,” “radial,” and “circumferential” are with respect to an orientation parallel to axis  81 , radius  82  (which is orthogonal to axis  81 ), and circumference  83 , respectively. The adjectives “axial,” “radial” and “circumferential” also are regarding orientation parallel to respective planes. To clarify the disposition of the various planes, objects  84 ,  85 , and  86  are used. Surface  87  of object  84  forms an axial plane. That is, axis  81  forms a line along the surface. Surface  88  of object  85  forms a radial plane. That is, radius  82  forms a line along the surface. Surface  89  of object  86  forms a circumferential plane. That is, circumference  83  forms a line along the surface. As a further example, axial movement or disposition is parallel to axis  81 , radial movement or disposition is parallel to radius  82 , and circumferential movement or disposition is parallel to circumference  83 . Rotation is with respect to axis  81 . 
     The adverbs “axially,” “radially,” and “circumferentially” are with respect to an orientation parallel to axis  81 , radius  82 , or circumference  83 , respectively. The adverbs “axially,” “radially,” and “circumferentially” also are regarding orientation parallel to respective planes. 
       FIG. 1B  is a perspective view of object  90  in cylindrical coordinate system  80  of  FIG. 1A  demonstrating spatial terminology used in the present application. Cylindrical object  90  is representative of a cylindrical object in a cylindrical coordinate system and is not intended to limit the present invention in any manner. Object  90  includes axial surface  91 , radial surface  92 , and circumferential surface  93 . Surface  91  is part of an axial plane, surface  92  is part of a radial plane, and surface  93  is part of a circumferential surface. 
     The following description is made with reference to  FIGS. 4 and 5A .  FIG. 4  is a top-half section view of torque converter  300  with a hub seal configuration and prime mover  115 .  FIG. 5A  is a detail view of region  5  in  FIG. 4  with a seal design including an o-ring, according to an example aspect. Seal  138  is urged in direction of arrow  148  by resilient element  150 . Element  150  may be a rubber o-ring, for example. Element  150  urges seal radial wall  152  into contact with groove radial wall  141  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . Element  150  is compressed in groove  140  between seal  138  and radial wall  143 . Seal  138  also seals to piston  102  at circumferential wall  154  of piston  102 . 
     The following description is made with reference to  FIG. 5B-5E .  FIG. 5B  is a detail view of region  5  in  FIG. 4  with a seal design including two floating seals and an o-ring, according to an example aspect.  FIG. 5C  is a detail view of region  5  in  FIG. 4  with a seal design including two floating seals with circumferential grooves and an o-ring, according to an example aspect.  FIG. 5D  is a detail view of region  5  in  FIG. 4  with a seal design including a floating seals with a fillet and an o-ring, according to an example aspect.  FIG. 5E  is a detail view of region  5  in  FIG. 4  with a seal design including a floating seals with a notch and an o-ring, according to an example aspect. 
     The description of the embodiment shown in  FIG. 5A  is generally applicable to the embodiments shown in  FIG. 5B-5E  except as described below. In  FIGS. 5B and 5C , seal  156  is disposed between resilient element  150  and radial wall  143 . Element  150  is compressed between seal  138  and seal  156 . In  FIG. 5C , seals  138  and  156  include respective circumferential grooves  158  and  160  for receiving element  150 . In  FIG. 5D , seal  138  includes fillet  162  for receiving element  150 . In  FIG. 5E , seal  138  includes notch  164  for receiving element  150 . 
     The following description is made with reference to  FIGS. 4 and 5F .  FIG. 5F  is a detail view of region  3  in  FIG. 2  with a seal design including a coil spring, according to an example aspect. Seal  138  is urged in direction of arrow  148  by resilient element  170 . Element  170  may be a coil spring, for example. Element  170  urges seal radial wall  152  into contact with groove radial wall  141  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . Element  170  is compressed between seal  138  and radial wall  172  of notch  174 . That is, hub  136  includes notch  174  for axially retaining coil spring  170 . 
     The following description is made with reference to  FIGS. 4 and 5G .  FIG. 5G  is a detail view of region  5  in  FIG. 4  with a seal design including a diaphragm spring, according to an example aspect. Seal  138  is urged in direction of arrow  149  by resilient element  180 . Element  180  may be a diaphragm spring, for example. Element  180  urges seal radial wall  153  into contact with groove radial wall  143  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . Element  180  is compressed between seal  138  and radial wall  182  of hub  136 . Wall  182  may be created by staking. That is, element  180  may be staked to hub  136 . 
     The following description is made with reference to  FIG. 5H .  FIG. 5H  is a detail view of region  5  in  FIG. 4  with a seal design including a coil spring and backing ring, according to an example aspect. The description of the embodiment shown in  FIG. 5F  is generally applicable to the embodiment shown in  FIG. 5H  except as described below. Piston plate  102  includes backing ring  175 . Ring  175  may be attached to piston  102  by rivet  176 , for example. Ring  175  includes radial wall  177  and circumferential wall  178 . Element  170  is axially retained by wall  177  and radially centered by wall  178 . 
     The following description is made with reference to  FIGS. 5I-5J .  FIG. 5I  is a detail view of region  5  in  FIG. 4  with a seal design including an annular ring, according to an example aspect.  FIG. 5J  is a radial view of the annular ring of  FIG. 5I  taken generally along line J-J in  FIG. 5I . Piston plate  102  includes annular ring  190  with axial tab  192 . Ring  190  may be attached to piston plate  102  by rivet  194 , for example. Axial tab  192  extends from ring  190  towards seal  138 . Tab  192  urges seal radial wall  152  into contract with groove radial wall  141  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . 
     The following description is made with reference to  FIG. 5K .  FIG. 5K  is a detail view of region  5  in  FIG. 4  with a seal design including an snap ring, according to an example aspect. Seal  138  is urged in direction of arrow  148  by resilient element  200 . Element  200  may be a snap ring, for example. Element  200  urges seal radial wall  152  into contact with groove radial wall  141  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . Element  200  is disposed in groove  140  between seal  138  and angled surface  204  of groove  140 . Angled, or conical, surface  202  of ring  200  is matingly engaged with angled surface  204 . Engagement of groove angled surface  204  with snap ring angled surface  202  urges snap ring  200  towards seal  138 . That is, snap ring  200  is a split ring expanded to fit into groove  140 , so tendency of ring  200  to contract urges ring  200  in the direction of arrow  148  due to interaction of angled surfaces  202  and  204 . 
     The following description is made with reference to  FIGS. 4 and 5L .  FIG. 5L  is a detail view of region  5  in  FIG. 4  with a seal design including an annular ring and a thrust washer, according to an example aspect. Hub  136  includes annular ring  210  with axial tab  212  disposed between flange  132  and thrust washer  214 . Washer  214  is attached to flange  132  with tabs  216 , for example. Axial tab  212  extends from ring  210  towards seal  138 . Tab  212  urges seal radial wall  152  into contract with groove radial wall  141  to restrict flow of oil as described supra. That is, seal  138  is sealingly engaged with hub  136 , thereby improving engagement of clutch  114 . 
     Of course, changes and modifications to the above examples of the invention should be readily apparent to those having ordinary skill in the art, without departing from the spirit or scope of the invention as claimed. Although the invention is described by reference to specific preferred and/or example embodiments, it is clear that variations can be made without departing from the scope or spirit of the invention as claimed.